EnvironmentalProtectionDepartment
AgreementNoCE45/99 ExtensionofExistingLandfills andIdentificationof PotentialNewWasteDisposalSites
FinalStrategicEnvironmentalAssessmentReport Volumel
January2003
ScottWilsonLtd Extension of Existing Landfills and Identification Scott Wilson Ltd of Potential New Waste Disposal Sites January 2003
VOLUME I – TABLE OF CONTENTS Page PART A – INTRODUCTION TO SEA AND METHODOLOGY
1. INTRODUCTION ...... 1-1 1.1 Background...... 1-1 1.2 Strategic Environmental Assessment Requirements...... 1-1 1.3 The Long-listed Sites ...... 1-2 1.4 SEA Methodology Working Paper ...... 1-4 1.5 Report Structure...... 1-5
2. STRATEGIC ISSUES...... 2-1 2.1 Environmental Impact Assessment ...... 2-1 2.2 Strategic Environmental Assessments – International Perspective...... 2-2 2.3 Strategic Environmental Assessment – Hong Kong ...... 2-3 2.4 Sustainability...... 2-4 2.5 Global Warming – Greenhouse Gasses ...... 2-6
3. THE CONSTRUCTION WORKS AND THEIR IMPLEMENTATION ...... 3-1 3.1 Introduction ...... 3-1 3.2 Artificial Islands – Construction...... 3-1 3.3 Artificial Islands – Outline Planning and Implementation Programme ...... 3-4 3.4 Land-Based Filling – Construction...... 3-6 3.5 Land-Based Filling – Outline Planning and Implementation Programme ...... 3-7 3.6 Coastal Reclamation – Construction ...... 3-8 3.7 Coastal Reclamation – Outline Planning and Implementation Programme...... 3-8 3.8 Principal Environmental Construction and Operation Issues...... 3-9
4. SEA METHODOLOGY...... 4-1 4.1 Outline of the SEA Methodology...... 4-1 4.2 Applying the Environmental Evaluation Framework ...... 4-3 4.3 Assumptions ...... 4-4
5. ENVIRONMENTAL IMPACTS AND EVALUATION CRITERIA ...... 5-1 5.1 Introduction ...... 5-1 5.2 Air Quality...... 5-1 5.3 Noise...... 5-5 5.4 Water Quality...... 5-8 5.5 Waste Management / Materials Balance ...... 5-11 5.6 Ecology ...... 5-14 5.7 Fisheries ...... 5-18 5.8 Cultural Heritage Impacts ...... 5-19 5.9 Landscape and Visual Impacts...... 5-21 5.10 Landfill Gas Issues ...... 5-27
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VOLUME I – TABLE OF CONTENTS Page PART B –SITE SPECIFIC DETAILS
6. DEEP BAY ISLAND LANDFILL...... 6-1 6.1 Basic Information...... 6-1 6.2 Outline of Planning and Implementation Programme ...... 6-2 6.3 Possible Impacts on the Environment ...... 6-2 6.4 Environmental Protection Measures to be incorporated into Design and Further Environmental Implications...... 6-13 6.5 Summary ...... 6-15
7. SHA CHAU ISLAND LANDFILL ...... 7-1 7.1 Basic Information...... 7-1 7.2 Outline Of Planning and Implementation Programme ...... 7-2 7.3 Possible Impacts on the Environment ...... 7-2 7.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 7-11 7.5 Summary ...... 7-13
8. LANTAU NORTH WEST ISLAND LANDFILL ...... 8-1 8.1 Basic Information...... 8-1 8.2 Outline Of Planning and Implementation Programme ...... 8-2 8.3 Possible Impacts on the Environment ...... 8-2 8.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 8-11 8.5 Summary ...... 8-13
9. SOKO ISLANDS LANDFILL...... 9-1 9.1 Basic Information...... 9-1 9.2 Outline of Planning and Implementation Programme ...... 9-2 9.3 Possible Impacts on the Environment ...... 9-2 9.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 9-10 9.5 Summary ...... 9-12
10. SOUTH CHEUNG CHAU SLAND LANDFILL ...... 10-1 10.1 Basic Information...... 10-1 10.2 Outline of Planning and Implementation Programme ...... 10-1 10.3 Possible Impacts on the Environment ...... 10-2 10.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 10-11 10.5 Summary ...... 10-12
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11. LAMMA BREAKWATER ISLAND LANDFILL...... 11-1 11.1 Basic Information...... 11-1 11.2 Outline of Planning and Implementation Programme ...... 11-1 11.3 Possible Impacts on the Environment ...... 11-2 11.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 11-12 11.5 Summary ...... 11-14
12. EAST TUNG LUNG ISLAND LANDFILL ...... 12-1 12.1 Basic Information...... 12-1 12.2 Outline of Planning and Implementation Programme ...... 12-2 12.3 Possible Impacts on the Environment ...... 12-2 12.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 12-10 12.5 Summary ...... 12-12
13. EASTERN WATERS ISLAND LANDFILL ...... 13-1 13.1 Basic Information...... 13-1 13.2 Outline Of Planning and Implementation Programme ...... 13-1 13.3 Possible Impacts on the Environment ...... 13-2 13.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 13-10 13.5 Summary ...... 13-12
14. TAI LONG WAN OFFSHORE ISLAND LANDFILL ...... 14-1 14.1 Basic Information...... 14-1 14.2 Outline of Planning and Implementation Programme ...... 14-1 14.3 Possible Impacts on the Environment ...... 14-2 14.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 14-11 14.5 Summary ...... 14-12
15. SOUTHEAST OFFSHORE ISLAND LANDFILL...... 15-1 15.1 Basic Information...... 15-1 15.2 Outline of Planning and Implementation Programme ...... 15-1 15.3 Possible Impacts on the Environment ...... 15-1 15.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 15-9 15.5 Summary ...... 15-11
16. LAMMA NORTH ISLAND LANDFILL...... 16-1 16.1 Basic Information...... 16-1 16.2 Outline Of Planning and Implementation Programme ...... 16-1 16.3 Possible Impacts on the Environment ...... 16-2 16.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 16-11 16.5 Summary ...... 16-12
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17. LAMMA SOUTH ISLAND LANDFILL ...... 17-1 17.1 Basic Information...... 17-1 17.2 Outline Of Planning and Implementation Programme ...... 17-1 17.3 Possible Impacts on the Environment ...... 17-2 17.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 17-10 17.5 Summary ...... 17-12
18. PILLAR POINT VALLEY NORTH LANDFILL ...... 18-1 18.1 Basic Information...... 18-1 18.2 Outline of Planning and Implementation Programme ...... 18-2 18.3 Possible Impacts on the Environment ...... 18-2 18.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 18-6 18.5 Summary ...... 18-8
19. NENT LANDFILL EXTENSION SITE...... 19-1 19.1 Basic Information...... 19-1 19.2 Outline of Planning and Implementation Programme ...... 19-2 19.3 Possible Impacts on the Environment ...... 19-2 19.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 19-7 19.5 Summary ...... 19-13
20. WENT LANDFILL EXTENSIONS SITE...... 20-1 20.1 Basic Information...... 20-1 20.2 Outline of Planning and Implementation Programme ...... 20-2 20.3 Possible Impacts on the Environment ...... 20-2 20.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications...... 20-8 20.5 Summary ...... 20-12
21. CONCLUSIONS AND RECOMMENDATIONS ...... 21-1 21.1 Introduction ...... 21-1 21.2 Approach to the Strategic Environmental Assessment...... 21-1 21.3 Brief Comparison of Environmental Impacts Associated with Land Based Sites and Marine Sites...... 21-3 21.4 Discussion of Impacts...... 21-4 21.5 Conclusions ...... 21-20
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22. STRATEGIC ENVIRONMENTAL MONITORING AND AUDIT...... 22-1 22.1 Introduction ...... 22-1 22.2 Design Issues to be taken into Account During the Development of a New Landfill Site / Extension to an Existing Landfill Site...... 22-2 22.3 Strategic Follow Up Actions...... 22-5 22.4 The Next Steps ...... 22-9
Appendix I: Extract of Final Water Quality and Hydrodynamic Assessment Report (November 2002) Appendix II: Technical Note: WENT and NENT Landfill Archaeological Relics (November 2002)
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Final Strategic Environmental Assessment Volume II
List of Figures
Figures No. Description
Figure 1.1 Site Location Plan
Figure 5.1 General Current Pattern in Hong Kong
Figure 5.2 EPD Sediment and Marine Water Quality Monitoring Station
Figure 6.1 Key Environmental Issues : Site M.1 Deep Bay Island Landfill
Figure 6.2 Programme for Implementation of Deep Bay Island Landfill (DBIL)
Figure 6.3 Deep Bay Island Landfill – Landscape Context
Figure 6.4 Deep Bay Island Landfill – Landscape Character Areas and Designations
Figure 6.5 Deep Bay Island Landfill – Approximate Visual Envelope
Figure 6.6 Deep Bay Island Landfill – Key Views
Figure 6.7A Deep Bay Island Landfill – Photomontages
Figure 6.7B Deep Bay Island Landfill – Photomontages
Figure 6.7C Deep Bay Island Landfill – Photomontages
Figure 6.8 Deep Bay Island Landfill – Outline Landscape / Visual Mitigation Measures
Figure 7.1 Key Environmental Issues : Site M.2 Sha Chau Island Landfill
Figure 7.2 Programme for Implementation of Sha Chau Island Landfill (SCIL)
Figure 7.3 Sha Chau Island Landfill – Landscape Context
Figure 7.4 Sha Chau Island Landfill – Landscape Character Areas and Designations
Figure 7.5 Sha Chau Island Landfill – Approximate Visual Envelope
Figure 7.6 Sha Chau Island Landfill – Key Views
Figure 7.7A Sha Chau Island Landfill – Photomontages
Figure 7.7B Sha Chau Island Landfill – Photomontages
Figure 7.8 Sha Chau Island Landfill – Outline Landscape / Visual Mitigation Measures
Figure 8.1 Key Environmental Issues : Site M.3 Lantau Northwest Island Landfill
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Figures No. Description
Figure 8.2 Programme for Implementation of Lantau Northwest Island Landfill (LNWIL)
Figure 8.3 Lantau North-West Island Landfill – Landscape Context
Figure 8.4 Lantau North West Island Landfill – Landscape Character Areas and Designations
Figure 8.5 Lantau North West Island Landfill – Approximate Visual Envelope
Figure 8.6 Lantau North-West Island Landifll – Key Views
Figure 8.7A Lantau North-West Island Landfill – Photomontages
Figure 8.7B Lantau North-West Island Landfill – Photomontages
Figure 8.8 Lantau North-West Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 9.1 Key Environmental Issues : Site M.4 Soko Islands Landfill
Figure 9.2 Programme for Implementation of Soko Islands Landfill (SIL)
Figure 9.3 Soko Islands Landfill – Landscape Context
Figure 9.4 Soko Islands Landfill – Landscape Character Areas and Designations
Figure 9.5 Soko Islands Landfill – Approximate Visual Envelope
Figure 9.6 Soko Islands Landfill – Key Views
Figure 9.7A Soko Islands Landfill – Photomontages
Figure 9.7B Soko Islands Landfill – Photomontages
Figure 9.8 Soko Islands Landfill – Outline Landscape / Visual Mitigation Measures
Figure 10.1 Key Environmental Issues : Site M.5 South Cheung Chau Island Landfill
Figure 10.2 Programme for Implementation of South Cheung Chau Island Landfill (SCCIL)
Figure 10.3 South Cheung Chau Disposal Grounds – Landscape Context
Figure 10.4 South Cheung Chau Island Landfill – Landscape Character Area and Designations
Figure 10.5 South Cheung Chau Island Landfill – Approximate Visual Envelope
Figure 10.6 South Cheung Chau Disposal Grounds – Key Views
Figure 10.7A South Cheung Chau Disposal Grounds – Photomontages
Figure 10.7B South Cheung Chau Disposal Grounds – Photomontages
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Figures No. Description
Figure 10.7C South Cheung Chau Disposal Grounds – Photomontages
Figure 10.8 South Cheung Chau Island Landfill – Outline Landscape / Visual Mitigation Measures
Figure 11.1 Key Environmental Issues : Site M.6 Lamma Breakwater Island Landfill
Figure 11.2 Programme for Implementation of Lamma Breakwater Island Landfill (LBIL)
Figure 11.3 Lamma Breakwater Island Landfill – Landscape Context
Figure 11.4 Lamma Breakwater Island Landfill – Landscape Character Areas and Designations
Figure 11.5 Lamma Breakwater Island Landfill – Approximate Visual Envelope
Figure 11.6 Lamma Breakwater Island Landfill – Key Views
Figure 11.7A Lamma Breakwater Island Landfill – Photomontages
Figure 11.7B Lamma Breakwater Island Landfill – Photomontages
Figure 11.8 Lamma Breakwater Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 12.1 Key Environmental Issues: Site M.7 East Tung Lung Chau Island Landfill
Figure 12.2 Programme for Implementation of East Tung Lung Chau Island Landfill (ETLIL)
Figure 12.3 East Tung Lung Chau Island Landfill – Landscape Context
Figure 12.4 East Tung Lung Chau Island Landfill – Landscape Character Areas and Designations
Figure 12.5 East Tung Lung Chau Island Landfill – Approximate Visual Envelope
Figure 12.6 East Tung Lung Chau Island Landfill – Key Views
Figure 12.7A East Tung Lung Chau Island Landfill – Photomontages
Figure 12.7B East Tung Lung Chau Island Landfill – Photomontages
Figure 12.8 East Tung Lung Chau Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 13.1 Key Environmental Issues: Site M.8 Eastern Waters Island Landfill
Figure 13.2 Programme for Implementation of Eastern Waters Island Landfill (EWIL)
Figure 13.3 Eastern Waters Island Landfill – Landscape Context
Figure 13.4 Eastern Waters Island Landfill – Landscape Character Areas and Designations
Figure 13.5 Eastern Waters Island Landfill – Approximate Visual Envelope
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Figures No. Description
Figure 13.6 Eastern Waters Island Landfill – Key Views
Figure 13.7 Eastern Waters Island Landfill – Photomontages
Figure 13.8 Eastern Waters Island Landfill - Outline Landscape/Visual Mitigation Measures
Figure 14.1 Key Environmental Issues: Site M.9 Tai Long Wan Offshore Island Landfill
Figure 14.2 Programme for Implementation of Tai Long Wan Offshore Island Landfill (TLWOIS)
Figure 14.3 Tai Long Wan Offshore Island Landfill – Landscape Context
Figure 14.4 Tai Long Wan Offshore Island Landfill – Landscape Character Areas and Designations
Figure 14.5 Tai Long Wan Offshore Island Landfill – Approximate Visual Envelope
Figure 14.6 Tai Long Wan Offshore Island Landfill – Key Views
Figure 14.7A Tai Long Wan Offshore Island Landfill – Photomontages
Figure 14.7B Tai Long Wan Offshore Island Landfill – Photomontages
Figure 14.8 Tai Long Wan Offshore Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 15.1 Key Environmental Issues: Site M.10 Southeast Offshore Island Landfill
Figure 15.2 Programme for Implementation of Southeast Offshore Island Landfill (SEOIL)
Figure 15.3 Southeast Offshore Island Landfill – Landscape Context
Figure 15.4 Southeast Offshore Island Landfill – Landscape Character Areas and Designations
Figure 15.5 Southeast Offshore Island Landfill – Approximate Visual Envelope
Figure 15.6 Southeast Offshore Island Landfill – Key Views
Figure 15.7 Southeast Offshore Island Landfill – Photomontages
Figure 15.8 Southeast Offshore Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 16.1 Key Environmental Issues: M.11 Lamma North Island Landfill
Figure 16.2 Programme for Implementation of Lamma North Island Landfill (LNIL)
Figure 16.3 Lamma North Island Landfill – Landscape Context
Figure 16.4 Lamma North Island Landfill – Landscape Character Areas and Designations
Figure 16.5 Lamma North Island Landfill – Approximate Visual Envelope
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Figures No. Description
Figure 16.6 Lamma North Island Landfill – Key Views
Figure 16.7A Lamma North Island Landfill - Photomontages
Figure 16.7B Lamma North Island Landfill - Photomontages
Figure 16.7C Lamma North Island Landfill – Photomontages
Figure 16.8 Lamma North Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 17.1 Key Environmental Issues : M.12 Lamma South Island Landfill
Figure 17.2 Programme for Implementation of Lamma South Island Landfill (LSIL)
Figure 17.3 Lamma South Island Landfill – Landscape Context
Figure 17.4 Lamma South Island Landfill – Landscape Character Areas and Designations
Figure 17.5 Lamma South Island Landfill – Approximate Visual Envelope
Figure 17.6 Lamma South Island Landfill – Key Views
Figure 17.7A Lamma South Island Landfill – Photomontages
Figure 17.7B Lamma South Island Landfill – Photomontages
Figure 17.8 Lamma South Island Landfill – Outline Landscape/Visual Mitigation Measures
Figure 18.1 Key Environmental Issues: Site L.1 Pillar Point Valley North Landfill
Figure 18.2 Programme for Implementation of Pillar Point Valley North Landfill (PPVNL)
Figure 18.3 Pillar Point Valley North Landfill – Landscape Context
Figure 18.3A Pillar Point Valley North Landfill – Landscape Resources
Figure 18.4 Pillar Point Valley North Landfill – Landscape Character Areas and Designations
Figure 18.5 Pillar Point Valley North Landfill – Approximate Visual Envelope
Figure 18.6 Pillar Point Valley North Landfill – Key Views
Figure 18.7A Pillar Point Valley North Landfill – Photomontages
Figure 18.7B Pillar Point Valley North Landfill – Photomontages
Figure 18.8 Pillar Point Valley North Landfill – Outline Landscape/Visual Mitigation Measures
Figure 19.1 Key Environmental Issues: Site E.2/3 NENT Landfill Extension Site
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Figures No. Description
Figure 19.2 Programme for Implementation of NENT Landfill Extension (NLES)
Figure 19.3 NENT Landfill Extension – Landscape Context
Figure 19.3A NENT Landfill Extension – Landscape Resources
Figure 19.4 NENT Landfill Extension – Landscape Character Areas and Designations
Figure 19.5 NENT Landfill Extension – Approximate Visual Envelope
Figure 19.6 NENT Landfill Extension – Key Views
Figure 19.7A NENT Landfill Extension – Photomontages
Figure 19.7B NENT Landfill Extension – Photomontages
Figure 19.8 NENT Landfill Extension – Outline Landscape/Visual Mitigation Measures
Figure 20.1 Key Environmental Issues: Site E.1 WENT Landfill Extension Site
Figure 20.2A Programme for Implementation of WENT A Landfill Extension (WLES(A))
Figure 20.2B Programme for Implementation of WENT B Landfill Extension (WLES(B))
Figure 20.3 WENT Landfill Extension – Landscape Context
Figure 20.3A WENT Landfill Extension – Landscape Resources
Figure 20.4 WENT Landfill Extension – Landscape Character Areas and Designations
Figure 20.5 WENT Landfill Extension – Approximate Visual Envelope
Figure 20.6 WENT Landfill Extension – Key Views
Figure 20.7A WENT Landfill Extension - Photomontages
Figure 20.7B WENT Landfill Extension - Photomontages
Figure 20.8 WENT Landfill Extension – Outline Landscape/Visual Mitigation Measures
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PART A INTRODUCTION TO SEA AND METHODOLOGY
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Extension of Existing Landfills and Identification Scott Wilson Ltd of Potential New Waste Disposal Sites January 2003
1. INTRODUCTION 1.1 Background 1.1.1 The Environmental Protection Department (EPD) has commissioned Scott Wilson Ltd, in association with the Enviros Group, Urbis Limited, GHK (Hong Kong) Ltd and BMT Asia Pacific Ltd, to carry out a Study into the Extension of Existing Landfills and the Identification of Potential New Waste Disposal Sites (Agreement CE 45/99). 1.1.2 The objectives of the Study are clearly set out in the Inception Report carried out under this agreement (Scott Wilson, May 2000). In summary, the objectives are to:
• Determine the future need for additional landfilling capacity and new waste disposal facilities, having regard to the generation of Municipal Solid Waste (MSW), Construction & Demolition Material / Waste, and other waste requiring disposal. • Identify measures to maximise the use of the available void space and to extend the life of the existing strategic landfills. • Identify those strategic landfills that are suitable for extension; develop possible extension schemes and determine the principal requirements. • Identify potential sites within Hong Kong that are suitable for the development of various types of new waste disposal facilities to meet Hong Kong’s waste disposal needs for the 30 years after exhaustion of the existing/extended landfills. • Formulate an implementation plan.
1.2 Strategic Environmental Assessment Requirements 1.2.1 In order to fulfil the above objectives, the Study Brief identifies the need for a Strategic Environmental Assessment (SEA) (page 7-8,9-10 clause ix) of extended and new sites. The Brief requires a level of detail … “such that collection of further detailed environmental information would be unlikely to affect the environmental recommendations and conclusions.” 1.2.2 The Study Brief has seven requirements for the SEA, which are summarised below:
(i) Establish baseline conditions (including water quality, air quality, noise, environmental control and mitigation measures currently in place, land use, habitats (ecology), marine traffic and road traffic related issues and access); (ii) Justify the selection of sites (on environmental and non-environmental grounds); (iii) Evaluate the potential environmental performance and their environmental acceptability (issues to be addressed include ecology, heritage/archaeology, landscape, noise, water, air, landfill gas hazards, sewage infrastructure, and cumulative effect); (iv) Draw SEA conclusions; (v) Identify potential improvements / mitigation for the selected site(s); (vi) Discuss the implications of the extensions and new sites in an SEA Report; (vii) Develop a Strategic Environmental Monitoring and Audit SEM&A programme.
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1.3 The Long-listed Sites 1.3.1 The sites to be assessed were determined through a site search process [see previous reporting]. The SEAs (in Part B, this Volume) include all 15 of the long-listed sites, as shown in Figure 1.1 (in Part C, Volume II): • M.1 Deep Bay. • M.2 Sha Chau. • M.3 Lantau North-west. • M.4 Soko Islands. • M.5 South Cheung Chau Disposal Ground. • M.6 Lamma Breakwater. • M.7 East Tung Lung Chau. New Sites • M.8 Eastern Waters. • M.9 Tai Long Wan Offshore. • M.10 Southeast Offshore. • M.11 Lamma North. • M.12 Lamma South. • L.1 Pillar Point Valley North. • E.1 NENT Landfill Extension. Extensions at Existing • E.2 & 3 WENT Landfill Extensions. Strategic Landfill Sites
1.3.2 Specific layouts for an artificial island at each of the marine sites were developed within the constraining site envelope. For most sites (eg. sites M.1, M.2, M.3, M.4, M.6, M.7, M.11 and M.12), the available area within the site envelope was the principle factor; with the island layout and shape maximised to fit the site envelope, whilst being of an efficient shape to minimise the cost of shoreline protection against wind and wave attack, especially under monsoon and typhoon conditions. Where the site envelope was larger, the artificial island was located away from shipping routes (eg sites M.8, M.9 and M.10 in Eastern Waters where container traffic is accessing the Mainland’s eastern ports, including the Yantian Container Terminal). For sites such as M.5, M.8, M.9 and M.10, the artificial island was located to maximise the distance from key sensitive receivers. Where possible in the context of other constraints, the artificial island was located in shallower water with lesser depths of marine deposits. 1.3.3 A scheme for each of the new sites was developed and these are described briefly as follows: Deep Bay (Site M.1) 1.3.4 The Deep Bay site would be located to the north of the existing WENT Landfill within the ecologically sensitive Deep Bay, and within the SAR boundary. Because the site would be relatively close to land, the site could be served by a road bridge to allow direct road delivery of waste. 1.3.5 The schematic layout developed for an artificial island on this site would result in a 670ha island with the landfill developed on the island having a capacity of about 110Mcum. Sha Chau (Site M.2) 1.3.6 The Sha Chau site would be located to the south west of Tuen Mun and east of Sha Chau Island. 1.3.7 The schematic layout developed for an artificial island on this site would result in a 350ha island with the landfill developed on the island having a capacity of about 50Mcum. Lantau North West (Site M.3) 1.3.8 The Lantau North West site would be located to the north west of Lantau, south west of the Hong Kong International Airport and directly west and adjacent to the Lantau coastline opposite Tai O.
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1.3.9 The schematic layout developed for an artificial island on this site would result in a 230ha island with the landfill developed on the island having a capacity of about 40Mcum. Soko Islands (Site M.4) 1.3.10 The Soko Islands site would be located to the west of the Soko Islands in an area previously used for sand dredging. 1.3.11 The schematic layout developed for an artificial island on this site would result in a 475ha island with the landfill developed on the island having a capacity of about 75Mcum. South Cheung Chau (Site M.5) 1.3.12 The South Cheung Chau site would be located to the south of the western end of Lantau and south of Cheung Chau to generally coincide with the area used for mud disposal, known as the South Cheung Chau Disposal Ground. 1.3.13 The schematic layout developed for an artificial island on this site would result in a 850ha island with the landfill developed on the island having a capacity of about 140Mcum. Lamma Breakwater (Site M.6) 1.3.14 The Lamma Breakwater site would be located to the south west of Lamma, and midway between Lamma and Cheung Chau; this site would be near to the previously PADS proposed Lamma Breakwater. 1.3.15 The schematic layout developed for an artificial island on this site would result in a 585ha island with the landfill developed on the island having a capacity of about 130Mcum. East Tung Lung Chau (Site M.7) 1.3.16 The East Tung Lung Chau site would be located on the western side of the Ninepin Group of Islands, and to the east of the Clear Water Bay Peninsula. 1.3.17 The schematic layout developed for an artificial island on this site would result in a 390ha island with the landfill developed on the island having a capacity of about 65Mcum. Eastern Waters (Site M.8) 1.3.18 The Eastern Waters site would be located on the eastern boundary of SAR waters and east of the Clear Water Bay Peninsula. 1.3.19 The schematic layout developed for an artificial island on this site would result in a 875ha island with the landfill developed on the island having a capacity of about 140Mcum. Tai Long Wan Offshore (Site M.9) 1.3.20 The Tai Long Wan site would be located on the eastern boundary of SAR waters and east of Tai Long Wan. 1.3.21 The schematic layout developed for an artificial island on this site would result on a 875ha island with the landfill developed on the island having a capacity of about 140Mcum. Southeast Offshore (Site M.10) 1.3.22 The Southeast Offshore site would be located on the south eastern boundary of SAR waters and east of Po Toi. 1.3.23 The schematic layout developed for an artificial island on this site would result in a 850ha island with the landfill developed on the island having a capacity of about 140Mcum. Lamma North (Site M.11) 1.3.24 The Lamma North site would be located to the northwest of Lamma.
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1.3.25 The schematic layout developed for an artificial island on this site would result in a 435ha island with the landfill developed on the island having a capacity of about 85Mcum. Lamma South (Site M.12) 1.3.26 The Lamma South site would be located to the south of Lamma within SAR waters. 1.3.27 The schematic layout developed for an artificial island on this site would result in a 450ha island with the landfill developed on the island having a capacity of about 65Mcum. Pillar Point Valley North (Site L.1) 1.3.28 The Pillar Point Valley North site would be located to the north of the existing Pillar Point Valley Landfill in the North West New Territories. The site would be located within the confines of a borrow area site designated within Defence Lot 16 (Castle Peak Firing Range). 1.3.29 The schematic layout developed for a landfill on this site (including access road) would have a 100ha footprint and would provide a landfill capacity of about 65Mcum. 1.4 SEA Methodology Working Paper 1.4.1 In July 2000 a draft SEA Methodology Working Paper was circulated to Government for their comment. The purpose of the SEA Methodology Working Paper was to identify the methods by which the assessment would be carried out, including identifying assessment criteria for each of the environmental disciplines; and developing a consistent framework that could be applied to each of the potential extensions / new sites. Various comments were received regarding the draft Working Paper and the methodology was subsequently discussed and agreed during a meeting with Government in October 2000. 1.4.2 The methods developed for this SEA have fully considered the Environmental Impact Assessment Ordinance (EIAO) and its associated Technical Memorandum (as well as other supporting environmental legislation) in order to follow its guidance on environmental acceptability and feasibility. 1.4.3 This SEA does not fully assess impacts in accordance with the EIAO, rather it aims to identify the most environmentally acceptable scheme(s) at a strategic level. Further, more detailed, assessments would follow during subsequent Technical Feasibility Statement (TFS) and Feasibility Studies, including an EIA under the EIAO, which recognises that any new landfill is a Designated Project.
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1.5 Report Structure Part A (Volume I) – Introduction To SEA And Methodology Section 2 Strategic Environmental Assessment Section 3 The Construction Works and their Implementation Section 4 SEA Methodology Section 5 Environmental Impacts and Evaluation Criteria
Part B (Volume I) – Site Specific Details Part C (Volume II) – Figures and Drawings
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2. STRATEGIC ISSUES 2.1 Environmental Impact Assessment 2.1.1 Environmental Impact Assessment (EIA) is the process of predicting and evaluating an action’s impacts on the environment, the conclusions to be used as a tool in decision-making. It aims to prevent environmental degradation by giving decision-makers better information about the consequences that development actions could have on the environment. Briefly, EIA involves:
• Reviewing the existing state of the environment and the characteristics of the proposed action (and possibly alternative actions). • Predicting the state of the future environment with and without the action (the difference between the two is the action’s impact). • Considering methods for reducing or eliminating any negative impacts; preparing an EIA report that discusses these points. • After a decision is made about whether the action should proceed, possibly monitoring the actual impacts of the action.
2.1.2 EIA, as an approach to environmental issues, can be characterised as multi-disciplinary and predictive. Project-based environmental assessment systems have been operating well in Hong Kong for more than 15 years, with formal legislation since April 1998, the EIA process has also been applied to major policies and planning strategies. 2.1.3 In addition to project level assessment, it is recognised that environmental assessment should also be applied to the earlier, more strategic tiers of decision-making – policies, plans, and programmes (referred to generically as PPPs). Consideration of environmental issues at these higher levels is known as Strategic Environmental Assessment (SEA). 2.1.4 The development of the proposed evaluation framework for the SEA for this Study has taken into account all existing environmental (and related) legislation. Of particular note are the Environmental Impact Assessment Ordinance (Cap 499, S.16) and Technical Memorandum that were formally adopted in April 1998. Under the EIAO, “designated projects” are projects and proposals that may create an adverse environmental impact. For the two landfill extensions the applicable designated projects are as follows: G1 A landfill for waste as defined in the Waste Disposal Ordinance (Cap. 354); and G4 A waste disposal facility, or waste disposal activity, for refuse.
2.1.5 For the new marine disposal sites, the types of designated projects would include the above and also the following: C1 Reclamation of > 5 hectares (including associated dredging works); C10 A marine dumping area; and C11 A public dumping area of not less than 2 hectares in size.
2.1.6 To aid identification of key issues, other designated projects that may apply to marine disposal sites on a case-by-case basis are introduced under the respective assessments in Part B.
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2.2 Strategic Environmental Assessments – International Perspective 2.2.1 There is no single SEA process that can be applied in all circumstances, rather there are principles and key elements that should be integrated into existing procedures for the formulation of PPPs. 2.2.2 Different countries adopt different approaches to SEA. For example, the European Union (EU) formally adopted SEA Directive 2001/42/EC on 5th June 2001. Forward thinking countries have already enacted such legislation, e.g. the Netherlands Government set up a statutory SEA system in 1987 and is currently strengthening it. The New Zealand authorities have required the preparation of SEAs since late 1991. The UK’s Department of the Environment, Food and Rural Affairs (DEFRA) has recently recommended procedures resembling those of SEA. 2.2.3 In some instances, SEA is seen solely as an extension of EIA for projects at an earlier stage in the decision-making process. However, in other instances it is seen as being closely linked to the concept of sustainability; SEA may be the most direct way of making judgements about sustainability operational. 2.2.4 In May 2001, the Final Report was released on SEA and Integration of the Environment into Strategic Decision-Making (Icon Consultants Limited, UK) which aimed to evaluate the role of SEA in integrating the environment into strategic decision-making. The focus of that study was on the way in which environmental considerations are included in PPP in all sectors, rather than simply raising the profile of environment policies. 2.2.5 The study reviewed 20 detailed case studies from the EU (e.g. Austria, Denmark, Germany, UK, etc.) and non-EU countries (e.g. Canada, New Zealand, etc.) and from one international financing institution (the World Bank), reflecting a range of SEA and integration mechanisms and geographical spread. This enabled the identification of four broad models of SEA that embrace environmental integration and SEA’s role within it:
• EIA-Inspired SEA – Originating from ecological and/or resource management disciplines, and includes a baseline assessment of the preferred option or alternative locations. There is more emphasis on technical methodologies and a necessity to undergo a systematic assessment procedure. This form of SEA is generally used at the programme level and is often an incremental development from EIA. • Policy Analysis / Appraisal-inspired SEA – Originating from political science, impacts of a preferred option are appraised against objectives. There is no baseline survey and often little or no direct public participation. This model is often seen within regional / spatial land use planning and sustainability appraisal. • Integrationary SEA – This focuses on an objective-led process and is a combination of the first two models. Impacts are appraised against a combination of an environmental baseline survey and objectives. The process begins early in the development of the policy and investigates alternative means of achieving these objectives. Public participation is normally an important component of the process. This form of SEA is most likely to be found where there is a strong national environmental legislation and policy framework. • Ad Hoc Mechanisms of Environmental Integration – These are a collection of independent institutions and processes such as roundtables, audit committees and state-of-the-environment reports. These tools often fulfil similar roles found within elements of an SEA. However, there is no systematic process providing discrete hooks into the developing policy.
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2.3 Strategic Environmental Assessment – Hong Kong 2.3.1 With regards to the SEA for this Study, it is the intention that the SEA would fulfil the objectives of being both an environmental assessment of a plan / programme and would take the findings of the SUSDEV21 Study into account and so include the objectives of sustainability into the decision-making process. 2.3.2 Whilst Hong Kong has no formal SEA legislation, the following list of studies are examples where the environmental assessment has been applied at the strategic and regional level:
• Port and Airport Development Strategy, 1989. • Tseung Kwan O New Town Feasibility Study of Opportunities for Further Development, 1989. • North Lantau Development Plan, 1992. • Railway Development Study, 1993. • North West New Territories (Yuen Long District) Development Statement Study, 1994. • Freight Transport Study, 1994. • Territorial Development Strategy Review, 1996. • Third Comprehensive Transport Study, 1999. • Second Railway Development Study, 2000. • Future Strategic Growth Areas - North Western New Territories, North Eastern New Territories, and Hong Kong Island South and Lamma, 2002.
2.3.3 From the examination of these Hong Kong SEAs, it can be concluded that SEA in Hong Kong generally follows the “EIA-Inspired” model described in paragraph 2.2.5. 2.3.4 The SEA Evaluation Framework, set out in Section 4, has been based on international good practice in the SEA field, including methods specified in the following: • EU Directive 2001/42/EC on Strategic Environmental Assessment (EU June 2001). • Guidance on the Methodology for Multi-Modal Studies (UK, DETR, 2000). • A New Deal for Trunk Roads in England: Guidance on the New Approach to Appraisal (NATA). (DETR, 1998). • Manual on SEA in the Framework of the Trans-European Transport Network - Strategic Environmental Assessment of Transport Infrastructure (European Commission, 1998).
2.3.5 Consideration has also been given to information in the following publications: • Strategic Environmental Assessment (Therivel, Wilson, Thompson, Heaney and Pritchard: Earthscan, 1992). • Environmental Assessment in Practice (Harrop and Nixon, 1999).
2.3.6 Within Hong Kong, there are a number of areas of global concern, which would need to be integrated into the SEA at a strategic level, rather that at a site-specific level. The two main areas are those of sustainability and of global warming – specifically greenhouse gases.
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2.4 Sustainability 2.4.1 In 1997, Planning Department commissioned the SUSDEV21 Study – a study aimed at plotting Hong Kong’s course towards sustainable development in the 21st Century. There are a number of guiding principles that were developed under SUSDEV21 that are relevant to the SEA for this Study. The following principles of sustainable development in Hong Kong have been integrated into the proposed evaluation framework (the following information is derived from SUSDEV21 publications): Natural Resources 2.4.2 The SUSDEV21 guiding principle for natural resources is: “ Hong Kong should promote the sustainable use of natural resources to minimise its ecological footprint through improving consumption efficiency, minimising the use of non-renewable resources and re-using, recycling waste and recovering energy from wastes. ”
2.4.3 Natural resources are finite, and the abstraction, processing and transport of those resources has multiple social, environmental and economic impacts locally, nationally and internationally. The efficient use of resources therefore plays a major role in economic, social and environmental sustainability, both within Hong Kong, nationally and internationally. Hong Kong has always been dependent upon natural resources lying beyond its boundaries. Thus, the sustainability of Hong Kong depends to a considerable extent upon the efficient use of both locally and externally sourced natural resources such as water and energy fuels. 2.4.4 The extraction of the maximum beneficial use from our natural resources minimises both the amounts consumed to meet our needs, and the amount of wastes requiring final disposal. This latter point relieves pressure upon another function that the environment performs, that of assimilating wastes and pollutants. 2.4.5 Human activity can relieve pressure on this assimilative role – an engineered landfill is a man- made enhancement of the natural methane-generating anaerobic process by which organic material decomposes. Extracting the energy from the collected methane reduces our dependence on other energy sources and reduces GHG contributions. Isolating polluting leachate from the environment (and subsequently treating it) reduces the need for the surrounding environment to assimilate this pollutant. Biodiversity 2.4.6 The SUSDEV21 guiding principle for biodiversity is: “ To maintain the biodiversity of Hong Kong and to minimise any threat which consumption in Hong Kong may have on biodiversity elsewhere. ”
2.4.7 Unlike other guiding principles, the value of biodiversity is not human centred; the protection of biodiversity recognises that Hong Kong's population, Government and activities should respect other species and their natural habitats, both within the SAR and in other regions affected by Hong Kong's cultural and economic development. 2.4.8 Hong Kong contains large areas of natural landscapes which support a diverse assemblage of plant and animal species ranging from rare mammals, such as the Chinese White Dolphin, to over two hundred species of butterflies and some 380 native species of trees. Hong Kong's highest values of biological diversity are concentrated in small habitat patches located throughout the SAR in both protected and unprotected areas.
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2.4.9 The concept of biodiversity is also attracting greater attention on an international level as large-scale habitat destruction in some countries is increasingly being viewed as depleting global biodiversity resources. Biodiversity provides a number of important support functions for the world's human population, including food and fibre, genetic resources (e.g. medicines and chemical ingredients for a variety of products), and ecological insurance against catastrophic change. Aside from these functions, biodiversity also contributes to amenity resources, such as recreational and scenic areas, and the assimilative capacity of the environment. Although Hong Kong is not a formal signatory to the Convention on Biological Diversity, there is a growing recognition that Hong Kong's biodiversity resources must be protected in order to demonstrate support for global conservation efforts.
Environmental Quality 2.4.10 The SUSDEV21 guiding principle for environmental quality is: “ Hong Kong should be pro-active in avoiding environmental problems for present and future generations, seek to find opportunities to enhance environmental quality, and minimise the unwanted side effects, locally, nationally and internationally, of development and inefficiencies such as air, noise and water pollution or land contamination. ”
2.4.11 Maintaining (or restoring) environmental quality is a basic concept of sustainability and is reflected in Agenda 21. It is important both for its own intrinsic value and for its defining role in the quality of life for the present and future human population. 2.4.12 High levels of environmental quality are generally associated with low levels of impact and low levels of wastage (inefficiencies) from human activities; increasing levels of pollution degrade the components of the environment (air, marine and freshwater, soil), and their ability to assimilate pollutants, with correspondingly poorer quality of life standards for the population of that environment as a result. This degradation manifests itself in many specific ways familiar to Hong Kong residents, such as declining air quality at street level, smog impeding visibility from local viewpoints, poor bathing water quality at beaches, and excessive noise throughout the urban areas. 2.4.13 The need for a good quality environment is not limited to the SAR; Hong Kong, as a highly developed economy, also shares global efforts in limiting its pollutant contributions to the global environment, for example the production and release of greenhouse gases. To preserve Hong Kong and global environmental quality for current and future generations, pollutant loading should be minimised and the environmental efficiency of current practices improved to restore and subsequently maintain the natural capital stock of the SAR.
Sustainability Assessment 2.4.14 On 31st October 2001, a question was asked in LegCo regarding the role of the Government’s Sustainable Development Unit (set up in April 2001) and the establishment of Sustainability Assessment (SA). The Chief Secretary (CS) replied on the possible future need for a SA for “an initiative or major programme that may bring about significant or prolonged implications to the economic, social or environmental condition of Hong Kong”. The CS added “an early assessment will help scope out cross-sectoral issues and sensitive areas that require special attention or further detailed examination by the relevant bureaux or departments”. 2.4.15 In December 2001, the SDU issued guidelines to Government Bureaux and Departments, and the requirement to conduct SAs for major projects has been implemented since April 2002.
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2.4.16 In terms of this Study, although the concept of sustainability is included in the SEA methodology and design approach, this SEA should not be viewed as a SA. The Sustainable Development Unit is presently finalising recommendations for conducting SA. 2.5 Global Warming – Greenhouse Gases 2.5.1 The Earth’s atmosphere contains a naturally occurring shield of "greenhouse gases" (GHGs). Radiant (short-wave) energy from the sun passes through the atmosphere and warms the earth’s surface. Some of this energy is reflected back to the atmosphere as infrared (long- wave) energy, which is blocked by the GHG shield and re-emitted back to the earth’s surface. This further warms the surface of the earth and the lower atmosphere. 2.5.2 It has been estimated that without this natural greenhouse effect, the Earth would be around 30°C cooler, on average, and too cold to support human life. However, it has also been observed that concentrations of GHGs are rising above their natural levels as a result of anthropogenic (man-made) influences. The potential long-term effects of these higher concentrations of GHGs on global climate are the subject of much international debate. 2.5.3 Internationally, landfilling of wastes has a significant effect upon the generation of GHGs. This section provides background information on GHG and describes the conditions against which the site-specific greenhouse gas issues have been addressed. To this end, and in the spirit of the SEA process, the approach to addressing GHG issues in this Study is not quantitative in nature, although numeric justification has been provided where it has been deemed necessary to support a qualitative conclusion. Further assumptions on the generation of GHGs for this Study are presented in Section 4.3.
International Effort 2.5.4 The global nature of climate change, has presented a unique need for inter-governmental co- operation to address the issues. This is focused through the Inter-governmental Panel on Climate Change (IPCC) established in 1988 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP). 2.5.5 Internationally, efforts to limit climate change caused by emissions of GHGs are centred on the United Nations Framework Convention on Climate Change (UNFCCC), established by the IPCC. This convention aims to stabilise the concentration of GHGs in the atmosphere at a level that would prevent dangerous interference with the climate system. The UNFCCC provides the overall policy framework for addressing climate change issues. The IPCC supports the UNFCCC through its work on methodologies for National Greenhouse Gas Inventories, which have been adopted by major Governments around the world. 2.5.6 The parties present at the Kyoto conference reached an agreement (the “Kyoto Protocol”) for limiting GHG emissions from “Annex 1” countries. The commitment was to reduce their greenhouse gas emissions to least 5% below their 1990 levels by the period 2008-2012. The revised requirement is to now reduce the emission levels of 6 GHGs below their 1990 levels by 2008-12. Although China has ratified to Kyoto Protocol on 3 September 2002 at the Johannesburg Conference on Sustainable Development, China is not an Annex 1 country and so this does not apply to China.
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Hong Kong Position 2.5.7 Currently, there is no relevant legislation and/or assessment criteria for GHGs in Hong Kong, However, in 1997 the Advisory Council on the Environment (ACE) indicated:
“Hong Kong cannot become party to the Convention. Nevertheless, Hong Kong recognises the objectives of the Convention. Although we have not announced the Convention’s objectives as our official policy aims, we have used them as a basis for our actions” (ACE paper 47/97).”
2.5.8 In the spirit of this commitment, Hong Kong is carrying out a number of initiatives to establish the extent to which Hong Kong’s activities contribute to global warming and any actions needed to control emissions. The Greenhouse Gas Emission Control Study is currently being carried out by EPD to determine the extent and effect of Hong Kong’s GHG emissions. This study will establish emission inventories for Hong Kong and assess the appropriate way forward in terms of emissions reductions.
Greenhouse Gas Assessment Rationale 2.5.9 To enable a standardised approach in determining emissions inventories, the IPCC guidelines establish the concept of Global Warming Potential (GWP) which is a measure of the warming capacity of the gas, relative to that of carbon dioxide (the most common GHG) over a 100-year time period. Actual values are then expressed in terms of the “carbon dioxide equivalent” to allow direct comparison. Carbon dioxide has a GWP of 1.0. 2.5.10 The aim of the Kyoto Protocol is to control the emissions of the six main GHGs, namely, Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs) and Sulphur Hexafluoride (SF6). Emissions of these gases are weighted GWP and the target is to reduce emissions in terms of total GWP. Thus, an increase in the emission of one gas can be offset by equivalent GWP reductions in others.
2.5.11 For the purpose of this assessment only CO2, CH4 and N2O are considered. Emissions of HFCs, PFCs and SF6 included in the Kyoto Protocol would not be significantly increased by either the transport of waste or the operation of a landfill facility. 2.5.12 The methodology adopted to evaluate emissions is based upon the guidelines provided by IPCC in which GWPs are utilised to combine emissions of different gases to arrive at a CO2 equivalent emission level. Internationally accepted GWPs, as detailed by the IPCC, are presented Table 2.1, below. The listed GWP represent a 100-year time horizon. Table 2.1: Global Warming Potentials of Greenhouse Gases (100 year time horizon)
Gas GWP Gas GWP
CO2 1 HFC-23 11,700
CH4 21 HFC-32 650
N2O 310 HFC-125 2,800 HFC-134a 1,300 PFC-116 9,200 HFC-143a 3,800 PFC-218 7,000 HFC-152a 140 PFC-410 7,000 HFC-227ea 2,900 HFC-236fa 6,300
SF6 23,900 HFC-245ca 560 Greenhouse Gases – the Global Situation
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2.5.13 The GWP of CO2 is lower than either CH4 or N2O, however, it is the most common GHG produced by anthropogenic activities and accounts for about 60% of the increase in global 1 warming (IPCC, 1992 ). In addition, CO2 also has a long (50-200yrs) life in the atmosphere. By far the largest source of CO2 emissions is the oxidation of carbon from burning of fossil fuels, which accounts for 70-90% of total anthropogenic CO2 emissions (IPCC, 1996).
2.5.14 The overall contribution of CH4 to global warming is second only to CO2. CH4 contributes to 2 approximately 24% of the global warming increase and N2O about 10% (IPCC, 1996 ). Primary sources of CH4 include, livestock, coal and natural gas, solid wastes and wastewaters. Actual amounts and relative proportions contributed from the different sources vary between different countries considerably.
2.5.15 CH4 from solid waste disposal contributes a significant proportion of annual global CH4 emissions, although the estimation is subject to a great deal of uncertainty. Estimates of global CH4 emissions from solid waste disposal range from about 5% to 20% of the total estimated emissions of 375Tg/yr from anthropogenic sources globally (IPCC, 19963). Greenhouse Gases – the Hong Kong Situation 2.5.16 At the time of writing, EPD’s Greenhouse Gas Emission Control Study has not been completed and so any assumptions or reported data referred to in this Report are subject to verification. 2.5.17 The principal sources of relevant data for Hong Kong are the Study on Sustainable Development for the 21st Century and the information presented in the Discussion Paper on Greenhouse Gases for the LegCo Panel on Environmental Affairs (dated 3 July 2001), which presents a slightly updated set of data to that shown in the SUSDEV21 Study. Both papers concur in that Hong Kong emissions reflect the global trend with CO2 being the most significant greenhouse gas, followed by CH4 and then N2O.
2.5.18 Between 1990 and 1997, CO2 emissions constituted 83-88% of the total emissions of GHGs in Hong Kong. Methane contributed 11-14% and N2O contributed 1-2%. 2.5.19 GHG emissions in Hong Kong have exhibited a general decline from the period from beginning 1994, This is as a result of a combination of factors, such as changes in modes of power generation, relocation of industry outside of Hong Kong and higher utilisation of public transport. Within this overall trend, the relative contribution of CO2 to total GHG emissions declined in comparison with the other GHGs from 1992 to 1997. 2.5.20 The Final Report of the SUSDEV21 Study categorised the key sources of GHG emissions (in 1997) as follows:
• Energy Industries (combustion of fossil fuels by power stations, transport, manufacturing industries and construction), accounted for 97% of CO2 emissions, 1% of CH4 emissions and 78% of N2O emissions. Of the 97% of CO2 emissions, about 64% came from power generation, and 24% came from transport related emissions.
1 IPCC (1992), Climate Change 1992: The Supplementary Report to the IPCC Scientific Assessment. The Intergovernmental Panel on Climate Change (WMO/UNEP) Cambridge University Press, UK.
2 IPCC (1996): Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories: Reference Manual.
3 IPCC (1996), Climate Change 1995. The Science of Climate Change. (J.T. Houghton, et al. (eds)). Published for IPCC World Meteorological Organization/UNEP, Cambridge University Press, UK.
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• Industrial Processes (emissions from physical/chemical transformation of materials, e.g. cement manufacturing, “towngas”, etc.) contributed to 3% of CO2 emissions. • Agricultural Activities (including livestock and manure management, cultivation, burning and soils) produced less than 1% of CO2, CH4 and N2O emissions. • Waste Management (including waste degradation in landfills, incinerators and wastewater and sludge treatment processes), accounted for less than 1% of CO2 emissions, 98% of CH4 emissions and 21% of N2O emissions. The principal source of CH4 emissions was from landfills.
2.5.21 The anaerobic degradation of wastes in a landfill results in the production of landfill gas, (LFG) which includes the GHGs CH4 and CO2. The proportion of CH4 in LFG varies but is typically around 60%. The actual amount and rate of LFG produced is a function of the quantity of organic material as well as factors controlling methanogenic bacteria including the availability of nutrients, moisture, pH and temperature.
2.5.22 Whilst CO2 is also a component of LFG, under the IPCC Guidelines, CO2 emissions from waste degradation are considered to be biogenic, rather than anthropogenic in nature. Oxidation of waste to produce CO2 is considered to be a natural process, which would occur with or without the processes of landfilling, and therefore is simply part of the natural process of carbon cycling. On the other hand, CH4 production is considered to be anthropogenic, were it not for human intervention to create an artificially anaerobic environment by landfilling, the process of methane generation would not occur.
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3. THE CONSTRUCTION WORKS AND THEIR IMPLEMENTATION 3.1 Introduction 3.1.1 This Section outlines the mode of construction and the statutory procedures for implementation of new sites and extensions. 3.1.2 Formation of the new sites and extensions options involves three different modes of construction, comprising:
• Artificial Island. • Land based Filling. • Coastal Reclamation. 3.1.3 Table 3.1, below, shows the method of construction for each proposed site, together with the site-name abbreviations used throughout the remainder of this Report:
Table 3.1: Long-Listed Sites
Method of Type Location Abbrev. Construction M.1 Deep Bay Island Landfill DBIL M.2 Sha Chau Island Landfill SCIL M.3 Lantau Northwest Island Landfill LNWIL M.4 Soko Islands Landfill SIL M.5 South Cheung Chau Island Landfill SCCIL M.6 Lamma Breakwater Island Landfill LBIL Artificial Island New Sites M.7 East Tung Lung Island Landfill ETLIL M.8 Eastern Waters Island Landfill EWIL M.9 Tai Long Wan Offshore Island Landfill TLWOIL M.10 Southeast Offshore Island Landfill SEOIL M.11 Lamma North Island Landfill LNIL M.12 Lamma South Island Landfill LSIL L.1 Pillar Point Valley North Landfill PPVNL Land based Filling Extension E.1 NENT Landfill Extension Site NLES Sites E.2&3 WENT Landfill Extensions Sites WLES + Coastal Reclamation
3.1.4 The SEA for each of the above sites will include an implementation programme in order to provide greater clarity on implementation issues.
3.2 Artificial Islands – Construction 3.2.1 Sites constructed as artificial islands are envisaged to be “co-disposal sites”, i.e., designated initially as a public filling area, to be followed by development and operation as a landfill. 3.2.2 A typical island site would range from 200 to 900 hectares in size and could accommodate a landfill with a capacity varying from around 40Mcum to 150Mcum. The island would be constructed in cells such that, on completion of the first phase of reclamation in Cell 1, landfilling operations could commence while the next phase of island formation is being carried out. This also allows for phased restoration and landscaping as each area of waste disposal is completed.
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3.2.3 Construction and subsequent operation as a landfill would entail the following: • Construction of an encircling seawall and shoreline protection in a series of two or three cells. • Public filling of the area behind the encircling seawall for a number of years in order to form an “artificial” island to provide the necessary land for subsequent landfill development. • Settlement / surcharging of reclamation. • Site preparation for landfill development. • Construction of a marine waste reception area and passenger / vehicle jetty. • Phased development of landfill, including environmental pollution control systems (leachate treatment, landfill gas management/utilisation, waste water treatment, etc.). • Provision of utilities. • Construction of offices, canteen, welfare facilities, etc. • Construction of landfill infrastructure (weighbridges, wheel washing, vehicle cleaning, vehicle maintenance, etc.). • Delivery of solid waste by marine vessel for landfilling. • Operation of landfill (compacting waste, placing daily cover, road construction, etc.). • Operation of landfill gas treatment facilities (including landfill gas utilisation) leachate treatment plant, etc. • Phased landfill restoration and landscaping.
3.2.4 In order to reduce the overall environmental impacts to the water column during construction, the design approach for the formation of the island sites is to eliminate the need for dredging of underlying muds during the reclamation process. Consequently the construction sequence allows for adequate settlement of the marine muds under the loading of reclamation fill and surcharging. 3.2.5 To provide suitable foundations, granular columns would be installed in the underlying muds to support the seawalls. Whilst this “no-dredge” technique is considered suitable for seawalls in sheltered areas, the ability of this approach to provide adequate stability for seawalls in more exposed locations is subject to verification. Some of the sites, (particularly those in southern and eastern waters) will be exposed to considerable wind and wave action and may require a dredged foundation trench to ensure adequate stability. For the purposes of this SEA and the water quality modelling exercise, a “worst case” approach was adopted that includes for dredging of the seawalls at sites in eastern and southern waters. However, the viability of the no-dredge option for all seawalls should be confirmed in subsequent stages of the project. 3.2.6 The sequence and method of construction for an artificial island with dredging for the “exposed” seawalls would be as follows:
(a) The first cell (cell 1) of the island would be constructed first; this typically would be an area of 200 to 350 hectares and would be in the most exposed part of the island. Once constructed, it would provide shelter for the remaining works. (b) Dredging of the marine muds to form a foundation trench for the most exposed seawall sections of cell 1 would be carried out. (c) The dredged foundation trench would be filled progressively with screened inert C&D material as the dredging progresses. (d) The seawall mound would be placed over the filled dredged foundation trench using screened inert C&D material. Oversize material (rock and concrete fragments) would be placed as outer protection on the seaward side of the mound.
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(e) With protection provided by the first section of seawall, the granular column reinforcement of the seabed under the footprint of the seawall on the more sheltered sides of the cell 1 could proceed. Any adverse water quality impacts (such as elevated suspended solids) arising from the placement of the granular columns would be monitored, to ensure water quality remained within an acceptable limits. (f) After the granular column ground reinforcement is completed, the seawall mound for the those parts of the cell 1 island would be constructed. The seawall mound would be progressed until it encircled the cell 1 island, but leaving a entry and exit point for barges on the least exposed side of the island. The entry and exit point would be protected by a floating boom and silt curtain to minimise the transport of sediment and floating litter. (g) With an encircling seawall formed, a 2 to 3m granular blanket layer would be put down over the seabed marine muds by barge bottom dumping across the footprint of the first area to be reclaimed within the encircling seawall. This granular blanket layer could be produced by processing C&D material through one of CED’s Material Sorting Facilities that includes a crushing plant. (h) Vertical band drains would be installed through the granular blanket layer into the underlying marine muds using barge mounted equipment. (i) Layers of C&D materials (unscreened) would be placed by bottom dumping over the completed granular blanket layer and vertical band drains. (j) The reclamation would be raised to, say, +8mPD (this includes a 2 m surcharge layer) and be left for a final 12-month settlement/surcharge period. (k) Surcharge would be removed. (l) Following completion of an area of reclamation sufficient to allow landfilling to commence (say, 50ha), a further area of reclamation within the cell 1 island would be reclaimed and the process continued until the reclamation of cell 1 was completed. (m) Subsequently the seawall would be extended to construct cell 2 and the process repeated.
3.2.7 The sequence and method of construction for an artificial island without seawall dredging would be as follows:
(a) The first cell (cell 1) of the island would be constructed first; this typically would be an area of 200 to 350 hectares and would be in the most exposed part of the island. Once constructed, it would provide shelter for the remaining works. (b) Granular column reinforcement of the seabed would be installed along the alignment of the cell 1 seawall. (c) As granular column reinforcement proceeds, the seawall mound would be constructed over the prepared foundation by the placing of screened inert C&D material. Oversize material (rock and concrete fragments) would be placed as outer protection on the seaward side of the mound. (d) The granular column reinforcement and the seawall mound construction would proceed until the encircling seawall of the cell 1 island was formed, but leaving a entry and exit point for barges on the least exposed side of the island. The entry and exit point would be protected by a floating boom and silt curtain to minimise the transport of sediment and flotsam. (e) With an encircling seawall formed, a 2 to 3 m granular blanket layer would be put down over the seabed marine muds by barge bottom dumping across the footprint of the first area to be reclaimed within the encircling seawall. This granular blanket layer could be produced by processing C&D material through one of CED’s Material Sorting Facilities that includes a crushing plant.
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(f) Vertical band drains would be installed through the granular blanket layer into the underlying marine muds using barge mounted equipment. (g) Layers of C&D materials (unscreened) would be placed by bottom dumping over the completed granular blanket layer and vertical band drains. (h) The reclamation would be raised to, say, +8mPD (this includes a 2m surcharge layer) and be left for a final 12-month settlement/surcharge period. (i) Surcharge would be removed. (j) Following completion of an area of reclamation sufficient to allow landfilling to commence (say, 50ha), a further area of reclamation within the cell 1 island would be reclaimed and the process continued until the reclamation of cell 1 was completed. (k) Subsequently the seawall would be extended to construct cell 2 and the process repeated.
3.3 Artificial Islands – Outline Planning and Implementation Programme Statutory Approvals 3.3.1 The island sites are not covered by any statutory plans. To facilitate the proposed reclamation project, preparation of a new statutory plan under the provisions of the Town Planning Ordinance to cover the proposed site would be required. 3.3.2 The reclamation would need to be gazetted under the Foreshore and Sea-bed (Reclamations) Ordinance. 3.3.3 The necessary feasibility studies (including marine traffic impact, environmental impact, ground investigations and preliminary design) as well as procedures under the Town Planning Ordinance (TPO) and the Foreshore and Sea-bed (Reclamations) Ordinance (FSRO) would need to be completed before final approval. 3.3.4 Assuming the necessary feasibility studies commence in 2004, ExCo Approval is envisaged in 2009. This programme is based on the guidance given in Planning, Environmental and Lands Bureau Technical Circular No. 3/97, and recognises that:
• The TPO was amended in April 1998 to the effect that a submission of a draft plan to the Chief Executive in Council (CEC) can be made within 9 months after the expiration of the exhibition period of the draft plan, and of any subsequent amendment to the draft plan. Also, on application by the Town Planning Board, the CEC may extend the 9 months period for not more than 6 months.
• Any artificial island project would be controversial and, for planning purposes, a 39- month period has been included in the programme for the parallel processing of a scheme under the TPO and the FSRO up to ExCo approval in view of the complexities involved in resolving possible objections, especially from Green Groups and the Fishing Industry. 3.3.5 As the landfill would be classified as a Designated Project (DP), under the EIAO the EIA would need to be issued for public inspection, prior to final approval and issue of an Environmental Permit (EP) under the EIAO. Works cannot commence unless a valid EP is in place. For any DP, the proponent needs to take in to consideration the requirements of Works Bureau Technical Circular No. 18/98, (also issued as Planning Environmental and Lands Bureau Technical Circular 10/98). This Circular has been updated and amended by Works Bureau Technical Circular No. 33/2001 and Works Bureau Technical Circular No. 19/98A issued in December 2001. The amendments to the procedures allow for statutory gazettal of public works projects in parallel with the EIA process, rather than on completion of the EIA process, as was previously the case. The decision as to whether the gazettal procedures should run in parallel, however, rests with the Works Director of the DP. If, as a result of the EIA, changes are necessary to the gazetted scheme, then re-gazettal may be required.
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3.3.6 At this stage of this Study, and in view of the expected complexities in approvals, it is envisaged that gazettal in parallel with the EIAO would not be carried out. 3.3.7 The feasibility studies would include a Recommended Outline Development Plan (RODP), based on which Planning Department (PlanD) would prepare an OZP for the proposed reclamation. Subject to agreement by the Town Planning Board (TPB), and after consulting relevant District Councils, the draft OZP would be published for public inspection. 3.3.8 In parallel with the preparation of the draft OZP, the proponent would follow the procedures laid down for authorisation under the FSRO. Upon completion of the feasibility studies, the proponent in consultation with the Lands Department (LandsD) would prepare a plan and notice for gazetting the reclamation under the FSRO. The gazetting of the reclamation under the FSRO would, as far as practicable, be at the same time that the draft OZP was published for public inspection. 3.3.9 After expiry of the public inspection period for the draft OZP, the TPB would consider and hear any objections received. The draft OZP, together with any unwithdrawn objections and a schedule of the amendments made to meet objections, would then be submitted to the CEC, who would consider whether or not to approve the OZP or refer it to the TPB for further consideration or amendment. 3.3.10 Similarly, after expiry of the objection period under the FSRO, the proponent, in consultation with LandsD, would consider objections received and seek to meet or overcome the objections. After giving the objectors an opportunity to express any further views, the proponent would submit the plan and scheme to the CEC, who would consider whether or not to approve the plan and reclamation, with or without amendments. 3.3.11 Ideally, submission to the CEC under the TPO and FSRO would be carried out simultaneously although Town Planning procedures must be completed prior to formal authorisation of the reclamation under the FSRO. 3.3.12 The proponent could submit a Public Works Sub-committee (PWSC) paper for partial upgrading of the PWP project to Category A for funds for consultants fees and detailed investigations in advance of, or in parallel with, the preparation of the submissions to the CEC. 3.3.13 If the CEC approves the OZP for the reclamation under the TPO and authorises it under the FSRO, the Secretary for the Treasury could then submit the finalised paper to PWSC immediately after the authorisation.
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Implementation Process 3.3.14 Once the project is in PWP Category A, a design for the reclamation for the public filling area could be finalised and construction tenders called. The Preliminary Implementation Programme is based on a seawall and reclamation contract for cell 1 of the island being awarded 15 months after ExCo and Finance Committee give their approval to the project. 3.3.15 This reclamation contract would utilise inert C&D material received from the various Public Filling Barging Points that should by then be set up around the SAR. 3.3.16 Accounting for the “additional” filling necessary to accommodate the settlement of the mud under sites, it is envisaged that a 900ha artificial island could take over 20 years to fill. 3.3.17 The island would be divided into two or three cells, each of which is say 200 to 300ha. 3.3.18 Within the cell 1 island, following completion of at least 50ha of reclamation, a 12-month surcharge and settlement period would be necessary, recognising that the reclamation (and subsequent landfilling) would be constructed over marine muds without dredging. 3.3.19 Subsequent to the surcharge period, it is envisaged that the landfill contractor would commence development of the landfill infrastructure, and within a further 24 months waste deposition could commence. 3.3.20 In parallel with the landfill development, the reclamation work to form the remainder of cell 1 of the artificial island would continue. Following completion of cell 1, the other cells would be formed in a similar way. Based on the start date for construction on the Preliminary Implementation Programme of 2011, completion of the entire island could be in the period 2020 to 2040, depending on the size of the island and the delivery rate of public fill. 3.3.21 If the landfill started to accept waste in 2019 and assuming it was accepting 15,000 tonnes of waste per day, it would have a life of about 20 years (based on a 100Mcum capacity), i.e. it would be full by say 2040. Nevertheless progress on the reclamation of the artificial island would need to match the intake of waste into the site. 3.4 Land Based Filling – Construction 3.4.1 Sites falling under this category include: • Pillar Point Valley North Landfill. • NENT B Landfill Extension. • WENT A Landfill Extension. • Land based area of WENT B Landfill Extension.
3.4.2 In all cases, the landfill would be developed by excavating a “landfill bowl” that would be lined and waste placed within it. 3.4.3 Construction and subsequent landfilling would entail the following: • Site clearance and resumption. • Construction or improvement of site access road as necessary. • Phased excavation of the landfill bowl, including rock excavation. • On completion of the first phase excavation, undertake landfill lining works in preparation for waste acceptance. • On-site reuse of excavated material (public fill) for landfill construction. • In accordance with phased excavation, conduct phased development of associated facilities such as landfill gas management system, leachate treatment plant, etc. • Provision of utilities, offices and staff facilities. • Construction of other landfill infrastructure, including weighbridges, wheel washing and vehicle cleaning facilities. • Operation of landfill, including compacting waste, placing cover, etc.
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• Operation of landfill gas treatment facilities (including landfill gas utilisation), leachate treatment plant. • Phased restoration landfill and landscaping works as waste cells are completed.
3.5 Land Based Filling – Outline Planning and Implementation Programme Statutory Approvals 3.5.1 The site of Pillar Point Valley North Landfill is in an area that is not covered by any statutory plan, although access to the site would require construction of a road access through a Green Belt zone under the coverage of the Tuen Mun OZP. 3.5.2 The NENT B Landfill Extension primarily falls within the area of the Wo Keng Shan OZP. For the extension scheme to go ahead a revised OZP would need to be approved. 3.5.3 The WENT A and WENT B Extensions are in an area that is not covered by any statutory plan. The District Planning Office of PlanD has advised that they have no programme to issue an OZP for this area. 3.5.4 Construction of new roads and any roads that require re-alignment would need to be gazetted under the Roads (Works, Use and Compensation) Ordinance. 3.5.5 The necessary feasibility studies (including environmental impact assessment, drainage impact, traffic impact, marine impact, ground investigation and preliminary design) would need to be completed; and would include the preparation of a RODP. 3.5.6 As the landfill would be a Designated Project under the EIAO, the EIA would be published for public inspection, leading to the issue of an Environment Permit (EP) under the EIAO before the construction and operation of the landfill. 3.5.7 Where land resumption is required, action would need to be taken under the Lands Resumption Ordinance.
Sites Requiring OZP or Revised OZP 3.5.8 The RODP prepared under the feasibility studies would be used as basis on which PlanD would prepare an OZP for the proposed development and carry out the necessary procedures under the Town Planning Ordinance. Subject to agreement by the TPB, and after consulting relevant District Councils, the draft OZP would be published for public inspection. 3.5.9 After expiry of the public inspection period for the OZP, the TPB would consider and hear any objections received. TPB may amend the OZP to meet the objections. The draft OZP, together with any unwithdrawn objections and a schedule of the amendments made to meet objections, would then be submitted to the CEC, who would consider whether or not to approve the OZP or refer it to the TPB for further consideration or amendment. 3.5.10 The proponent could submit a PWSC paper for partial upgrading of the PWP project to Category A for funds for consultants fees and detailed investigations in advance of, or in parallel with, the preparation of the submission to the CEC. 3.5.11 If the CEC approves the OZP, the Secretary for the Treasury could then submit the finalised paper to PWSC immediately after the authorisation.
Sites Not Requiring OZP 3.5.12 Once the RODP prepared under the feasibility studies is agreed amongst Government Bureau(x) and Department, and endorsed by CPLD, the development of the site could proceed. 3.5.13 Once the RODP is endorsed by CPLD, the proponent could submit a PWSC paper for upgrading of the PWP project to Category A for funds for consultants fees and detailed investigations.
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Implementation Process 3.5.14 Once the project is in PWP Category A and, provided all statutory procedures are completed, tenders documents could be prepared and tenders called for the development and operation of the landfill under a DBO contract (subject to other studies that confirm the DBO form of contract is to be used). An alternative approach could be to let an advance works contract to provide some initial infrastructure followed by the DBO contract. In the case of the Pillar Point Valley North Landfill, an advance works contract could be let for the construction of the access road to the site. 3.6 Coastal Reclamation – Construction 3.6.1 The only site to fall under this category is the WENT B Extension. 3.6.2 The area occupied by the existing CLP Pulverised Fuel Ash (PFA) Lagoons would have to be filled and surcharged. Only the construction methodology for this area is described here, the construction methodology for the remainder of the WENT B Extension is described under Section 3.4. 3.6.3 Construction would entail the following: • Site clearance of existing CLP area. • Construction of seawall; it is envisaged that this would involve construction of a new seawall on the alignment of the existing CLP bund or parallel to it. • Filling of lagoon area behind seawall using public filling material. • Settlement and surcharging of filled area. • Site preparation for landfill development and road diversion. • Phased development of landfill. • Construction of road diversion.
3.7 Coastal Reclamation – Outline Planning and Implementation Programme Statutory Approvals 3.7.1 It may be necessary to gazette the lagoon area under the FSRO particularly if the new seawall extends outside the area previously gazetted for the CLP Lagoons. The necessity for any gazettel, if the proposed filling was entirely within the CLP area, would need to be decided. 3.7.2 In any event, CLP have a licence to use the lagoons area until 2047 and currently they have indicated that unless this site is re-provided, they would be reluctant to surrender the site any earlier. Currently CLP use the lagoons area for the deposition of surplus PFA from the burning of coal at the Castle Peak Power Station. Although the Black Point Power Station burns gas, it is understood that an allowance was made in the operation of this power station to permit the fuel to be switched to coal, if economic/financial factors dictate this. Therefore the lagoons could potentially also take PFA from Black Point Power Station as well. 3.7.3 Taking a conservative assumption that the site would need to be gazetted under the FSRO, a similar sequence would need to be followed as that described under Section 3.3.
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Implementation Process 3.7.4 The implementation programme for the WENT B Extension has assumed that the landward area would be acquired first and the CLP lagoon area would be surrendered later, say in 2015. It is assumed that agreement would be reached with CLP by early 2004 for surrender of the area of the lagoons in 2015 and allows time for the TPO and FSRO procedures (as necessary). 3.7.5 The Preliminary Implementation Programme for the WENT B Landfill assumes that the landward part of the site would be developed initially and allows landfilling to proceed in that area, with the lagoon area being included in the site in 2015. 3.8 Principal Environmental Construction and Operation Issues 3.8.1 The following sections outline the main issues and design approach to combating the principal environmental impacts associated with landfill construction and operation, namely, good site practice and the management of leachate and LFG. These issues are considered to be fundamental to the pursuit of sustainability in the development, management and aftercare of the landfill, irrespective of its location, and are thus common to all sites.
Good Site Practice 3.8.2 Good site practice is generally recommended to reduce the impacts of construction and operation primarily to air, noise and water. The specific mitigation requirements (if any) at each site would need to be determined during the EIA. 3.8.3 In terms of air quality, good site would include reduction of dust and odour by:
• Paving and subsequent regular sweeping of long-term haul roads within the site. • Regular dampening of unpaved roads. • Vehicle washing (both body wash and wheel wash) before leaving site. • Immediate cover to odorous waste, eg. sludge, after disposal • Daily covering of the current tipping face with inert material (e.g. selected construction and demolition material, tarpaulin covers, foam spray, etc.). • Interim cover of any operational areas which are not currently in use. • Design of enclosed-loop leachate collection / management system; • Proper design, operation, management and maintenance of landfill gas combustion facilities to ensure destruction of odorous organic compounds.
3.8.4 In terms of noise levels, good site management would include:
• Using powered mechanical equipment with built-in acoustic shielding. • Not using percussive piling. • Where necessary, constructing temporary noise barriers and/or earth bunds.
3.8.5 In terms of water quality, good site management would include:
• Providing adequate surface water collection systems (both temporary and permanent) to channel potentially muddy and/or contaminated water away from watercourses. • Providing sedimentation tanks for surface water prior to discharge to reduce the levels of suspended solids. • Regular cleaning of sedimentation tanks to ensure they operate efficiently, especially during the wet season.
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Leachate Collection and Treatment 3.8.6 The landfilling of waste gives rise to a contaminated liquid known as leachate. As organic waste within a landfill breaks down, it releases a number of highly polluting materials that dissolve in any water that infiltrates or is present in the landfill. The leachate that is formed as a result of this process percolates through the waste, and unless it is controlled, would seep out of the base of the landfill and pollute any bodies of water it mixes with. 3.8.7 The conventional approach to leachate management is that the design and operation of a landfill should minimise the amount of water that enters the waste, and control its migration from the site. The landfill design should provide for containment, with a low permeability liner to the landfill base sides and cap. The design and sequence of components in the liner would be subject to detailed consideration at a later stage. Essentially however, it is likely to require some or all of the following components: • Filter geotextile. • Leachate drainage. • Cushion geotextile. • Composite low permeability geomembrane. • Cushion Geotextile. • Groundwater drainage (if any).
3.8.8 If possible, landfilling should commence early in the dry season, and the active working areas through which water most readily enters the waste should be kept to a minimum. In this way, the quantity of infiltration would be minimised. 3.8.9 Any surface water accumulating on the surrounding land should be prevented from flowing into the landfill and the waste. This would be done by intercepting the surface water that could flow into the site and draining it away from the landfill. During waste disposal operations, “clean” surface water within the landfill area should also be segregated and disposed of separately from contaminated water or leachate. 3.8.10 A capping layer should be laid progressively over the exposed operational areas of waste or the final restoration surfaces of the landfill. The final capping layer should include a low permeability membrane placed on a layer of compacted fill. The membrane should be overlain by a drainage layer, compacted fill and soil/sub-soil. 3.8.11 Within the leachate drainage layer, lying immediately above the basal liner, there would be a series of regularly spaced slotted leachate collection pipes, most likely in a herringbone pattern, leading to a central spine drain in each phase. These main spine drains would run in the direction of the slope of the base, and act as the principal conduits for the collected leachate, which would be extracted from the low point via a sidewall riser pipe and would then drain by gravity or be pumped to the leachate treatment facilities. 3.8.12 The leachate generated by typical Hong Kong waste would likely have a high organic load, high oxygen demand, and high ammonia content and would require some form of treatment to bring it up to an acceptable level for discharge into the local sewage system (for subsequent downstream treatment) or directly into a natural water body. 3.8.13 The risk of settlement of the landfill base (perhaps exacerbated by the “no dredge” construction) would be monitored to ensure the performance of the leachate collection system performance remains unaffected 3.8.14 The performance requirements for the leachate treatment plant should ensure that no unacceptable water quality impacts arise from the effluent – this is fundamental to the operation of the landfill. In case of breaches, or temporary excessive leachate generation within the landfill that exceeds the capacity of the leachate treatment plant, provision should be made to re-circulate leachate within the landfill, or else store it in temporary ponds within the site for treatment at a later date – this is common existing practice within Hong Kong.
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3.8.15 There are a number of leachate treatment plants currently operating in Hong Kong at operational landfills and at the restored landfills. The technology employed at each landfill is not necessarily the same – at NENT leachate is treated by aeration lagoons, whereas at SENT, WENT and most or the restored landfills, modular Sequential Batch Reactors with ammonia stripping are utilised. Irrespective of the design, however, all leachate treatment facilities are required to produce an effluent that complies with the performance specification in terms of maximum or minimum values for a range of physical and chemical parameters. 3.8.16 The design of the leachate treatment plant depends upon a number of factors, including: • Strength of leachate (in terms of physical and chemical properties). • Leachate production rate (maximum, minimum and seasonal averages). • Area available to construct the treatment plant. • Contractor’s experience and preference of various technologies. • Effluent discharge requirements (in terms of total loading).
3.8.17 Given the number of factors that determine treatment plant design, in terms of this SEA the actual technology employed to treat leachate is not as important as the recognition that whatever technology is eventually used, the effluent from the plant should comply with discharge standards specified by EPD and so be deemed acceptable.
Landfill Gas Collection and Utilisation 3.8.18 Combined with air, methane forms an explosive mixture when exposed to an ignition source under suitable conditions. LFG accumulating in a restricted space, such as in a building or a room, presents a risk of suffocation because of oxygen displacement and toxic effects of elevated carbon dioxide. Carbon dioxide is also phytotoxic, and can displace soil oxygen. 3.8.19 The LFG mixture has a density similar to that of air, although this varies according to its exact composition. Upward movement of LFG is usually a result of excess pressure over ambient conditions rather than buoyancy. Changes in atmospheric pressure will influence venting of landfill gas to atmosphere as well as subsurface lateral migration. 3.8.20 Bulk gas movements may be caused by the pumping effect of a rising water table, whereas sub-surface lateral diffusion through semi-porous strata and cracks and faults may also be due to a concentration gradient. 3.8.21 Because of the risks associated with uncontrolled off-site migration, LFG should be positively managed within a landfill by means of a LFG containment and collection system. The landfill liner, primarily designed to contain leachate, should also be designed to restrict any possible off-site migration. Primary control should consist of slotted vertical extraction wells and rockfilled collector trenches constructed within the landfill at regular spacings. The vertical pipework would be connected to horizontal collector systems laid on the final surface of the waste, allowing for extraction to a LFG. Secondary control should be a perimeter system of wells and vent trenches designed to intercept any gas at the boundary of the site. 3.8.22 Based on environmental considerations, energy efficiency and availability of alternative users, as much LFG as possible should be utilised either on site or off site. LFG that cannot be utilised should be flared to reduce odour and emissions of VOCs. 3.8.23 Exhaust emissions from the thermal destruction of landfill gas have the potential to cause air quality impacts in the areas surrounding the thermal oxidiser (flare). The destruction efficiency of landfill gas flares is a function of its design and is affected by the design temperature and the “residence time” of landfill gas within the combustion chamber. All of the strategic landfills and most of the restored landfills in Hong Kong use thermal oxidisation systems for the destruction of landfill gas. Through performance specifications and careful siting of a flare within the landfill coupled with verification through modelling and monitoring, all have been shown to operate within the relevant AQOs
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3.8.24 Energy production from LFG generally requires some degree of processing, to remove contaminants. The viability of any off-site gas to energy project is subject to detailed analysis of the associated costs and the local environmental impacts. Such schemes tend to be most effective when the user demands for LFG match the production rates and the user/customer is within close proximity to the LFG source. Typical uses for LFG, both on-site and off-site, include:
• Electricity Generation by Internal Combustion Engines or Turbine Engines – LFG could be used on the landfill site to provide all electricity requirements. Surplus electricity, could be sold directly to off-site users or sold to utilities operators and input to the grid system, however, this off-site use would depend upon the availability of electricity transmission infrastructure in the locality.
• Direct Gas Use in Boilers or Industrial Processes – LFG could be used on the landfill site to provide process heat, for example to ammonia stripping process in the leachate treatment plant. Surplus gas could be directly utilised off-site as a medium- energy fuel for processes such as kiln operations, cement manufacture or asphalt production where the LFG is used as a replacement or supplementary fuel. Again, this off-site use would depend on the nearby location of such industries.
• Natural Gas Pipeline Injection – LFG could be processed and sold to a natural gas supplier. This technique is feasible where large volumes of LFG are available for a significant period of time but again required suitable infrastructure to be in place and a potential market for natural gas close by. 3.8.25 In practice, the most viable LFG utilisation option (other than on-site use) is likely to be the generation of electricity for off-site distribution and sale. This would require the co-operation of the relevant electricity utility company, a sale and purchase agreement, and agreement with Government with respect to the allocation of costs, revenues and risks associated with LFG utilisation.
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4. SEA METHODOLOGY 4.1 Outline of the SEA Methodology 4.1.1 The Study Brief states that the consultants should “carry out strategic environmental assessment for: - the potential extensions; - those sites short-listed for the development of waste disposal facilities.”
4.1.2 The Consultants’ interpretation of the requirement for SEA is that environmental screening should be used in the decision-making process from the outset of the Study. For this project, this began by identifying the “Areas of Absolute Exclusion” (see New Sites Studies: Site Selection Exercise (Revised) – Scott Wilson, September 2000) where landfills would not be permitted. The major areas identified for exclusion included:
• Existing and proposed areas of residential, commercial and industrial use. • Existing and proposed areas for port and airport use. • Existing and proposed areas for Government, Institution or Community use. • Existing and proposed village areas. • Existing and proposed Country Parks, Marine Parks and Marine Reserves. • Sites of Special Scientific Interest. • Ramsar sites. • Water gathering grounds. • Major infrastructure areas. • Fairways and shipping lanes.
4.1.3 Following the elimination of “Areas of Absolute Exclusion”, a long-list of potentially available sites in the SAR of the required size was identified for possible development as landfill sites. The long-listed sites were screened at a broad brush level taking account of a number of criteria (see Working Paper WP 3.1 (Revised) – New Sites Studies : Site Search Short-list – Scott Wilson, January 2001 and Short Note – Landfill Extensions Studies : Long-list of Sites – Scott Wilson, October 2000):
• Planning, lands and social factors. • Environmental factors (including detailed water quality monitoring, ecological, cultural heritage and landscape & visual impacts). • Engineering factors (including ground conditions and ease of construction). • Traffic and access.
4.1.4 The long-listed sites were evaluated against these criteria and a number of extension sites and potential new landfill sites were short-listed. 4.1.5 Following this, further environmental screening is to be applied at a more detailed level to all the sites selected, to ascertain the likely environmental affects – this is documented within this SEA Report. 4.1.6 In effect, progressively finer environmental screening and assessments are used – from the development of a long list of sites, to the drawing up of a short list, to assessing potential impacts of a preferred option. This process is in line with the purposes and meaning of SEA outlined in Section 2 of this SEA Report. 4.1.7 In order to efficiently and effectively carry out the seven requirements of the SEA set out in the Study Brief (outlined in Section 1), an assessment framework for the SEA was agreed with Government. The intention is that the SEA would act as a key decision-making tool in determining the options available for the provision of future waste disposal facilities.
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4.1.8 The objective of the assessments is to provide a comparative assessment and qualitative evaluation of key environmental issues, which leaves a fully auditable trail so that the decision-making process is fully transparent. In summary, the overall methodology is set out below:
• Agree the SEA evaluation framework. • Establish the necessary baseline environmental conditions surrounding the landfills and across the SAR (to identify new sites). • Present baseline data, relevant environmental standards and legislation and sensitive receivers. • Carry out preliminary environmental (and other) screening in order to short list sites. • Apply Framework to screened short-list. • Assess new sites / extensions in terms of their environmental performance. • Select preferred new site / extension options.
4.1.9 It is stressed that the impact assessment has not been carried out to the same level of detail as required by the EIAO, although the evaluation has considered the need to be able to identify whether the landfill new site or extension option is environmentally feasible. The SEA takes into consideration the potential short-term, long-term, residual, cumulative and trans- boundary environmental implications of each landfill new site or extension option. 4.1.10 Delft 3D water quality modelling has been carried out to allow a better understanding of the water quality impacts of the proposed landfill site. Simulations were carried out for 15-day spring-neap tidal cycles during the dry and wet seasons. Baseline conditions, and scenarios with the proposed island during both construction phase and operational phase were simulated. The construction phase was further sub-divided into 3 phases to reflect the change in hydrodynamic conditions due to the presence of island and the dredging/dumping rate at different stages. The water quality impact assessments in this SEA were based on the detailed modelling results presented in the Water Quality and Hydrodynamic Assessment Report1. 4.1.11 Strategic environmental conclusions are drawn based on the outcome of the impact evaluations and includes local environmental issues as well as regional issues such as air quality and aquatic environment characteristics and global issues such as greenhouse gas emissions. 4.1.12 Where required, specific environmental mitigation measures are identified through which environmental impacts can be controlled to within acceptable levels. This assessment aims to build on the mitigation measures already in place at the strategic landfill sites such as existing landfill and leachate control/treatment systems. 4.1.13 In addition, recommendations for a Strategic Environmental Monitoring and Audit (SEM&A) programme are made. The SEM&A is intended to identify major follow-up actions for the subsequent planning, design and operation phases, to identify the parties required to facilitate these actions, and to enable to facilitate auditing of the assumptions made in this SEA. Section 22 provides further discussion of SEM&A. 4.1.14 Based upon the strategic environmental assessments highlighted above, specific conclusions are drawn regarding the environmental acceptability of the new sites / extension options – these conclusions facilitate the further assessment in future PPFS, Feasibility Studies and site-specific EIAs.
1 EML(2002).Water Quality and Hydrodynamic Assessment Report.
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4.2 Applying the Environmental Evaluation Framework 4.2.1 Having identified potential new sites and extensions, further environmental screening was carried out of these long-listed sites based on a set of strategic evaluation criteria, documented in the SEA Methodology Working Paper. The evaluation criteria set out below follow the basic principles and guidelines of the EIAO and its associated Technical Memorandum, without going into quantitative assessment processes. The purpose of this approach is to facilitate further consideration of the short listed options under the EIAO process as part of further studies emanating from this current Assignment. 4.2.2 The development of the proposed evaluation framework for the SEA has taken into account all existing environmental (and related) legislation. Of particular note, the EIAO (Cap 499, S.16) and its associated Technical Memorandum on the Environmental Impact Assessment Process, and Hong Kong Planning Standards. 4.2.3 The environmental sub-criteria which will be assessed, in terms of this SEA, are: • Air Quality. • Noise. • Water Quality (including freshwater, marine waters & groundwater). • Waste Management. • Ecology. • Fisheries. • Cultural Heritage. • Landscape and Visual. • Landfill Gas Issues.
4.2.4 All sub-criteria are given equal weighting within the environmental evaluation framework, which is common practice in SEA. Instead, focus is giving to identifying the major issues for each of the proposed sites, likely mitigation measures required, and likelihood or difficulty to address the impacts satisfactorily. This would facilitate an informed decision at the early stage. 4.2.5 Within each of the sub-criteria, various influencing factors determine the overall impacts related to that issue. For example, if noise impacts are considered, key influencing factors would be the distance between the landfill and the sensitive receiver, the number of sensitive receivers affected, the topography, etc. For each “influencing factor” a symbol has been applied as follows within the evaluation:
“+ +” Positive – High “+” Positive “O” Neutral “O / -” Neutral / Negative – Low “-” Negative – Low “- / - -” Negative – Low / High “- -” Negative – High
4.2.6 The evaluation for each site is accompanied by a commentary outlining a description of the scheme and the key environmental issues associated with development at that site. As construction and operation of major strategic landfills happens concurrently, the impacts of construction and / or operation are combined (i.e. assessed together). Thus impacts are assessed for the “construction / operation phase”.
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4.2.7 The evaluation of impacts for each sub-criterion has been based on a combination of qualitative judgement and quantitative assessment. Whilst the assessment process presented in Part B uses the score technique for clarity, the final evaluation is based upon professional judgement and it is not the intention that the scores for each site are compared numerically. 4.3 Assumptions General Environmental Controls 4.3.1 In addition to the best practice approach to environmental design of landfills described in Section 3.8 it is assumed that standard environmental controls are put in place contractually during construction and operation to minimise noise, dust emissions, polluted runoff, etc. in accordance with the NCO, APCO, WPCO and other relevant legislation. Hence the assessment assumes standard mitigation measures and good site practice are in place for any new site or extension. Such generic measures are outlined in Section 5. Plant and Operating Methods 4.3.2 Any new site or extension would have approximately the same number and type of plant operating on it. As it is also assumed that all operating procedures would be more or less the same, noise and dust emissions from the site would be more or less equal. LFG and GHG 4.3.3 Irrespective of location, landfill gas collection and management systems and leachate collection and treatment systems would operate to the same environmental performance criteria, in terms of efficiency and effluent quality, and would therefore have similar impacts on the environment. 4.3.4 For any landfill new site or extension, it is assumed that the same types of waste are received and daily waste inputs (whether by road, rail or marine) would be more or less equal. 4.3.5 It is further assumed that LFG emissions from a new and / or extended landfill would be essentially similar per unit mass of waste delivered and that the LFG would be controlled by similarly efficient gas management systems. This being the case, it is assumed that GHGs would be essentially similar for any landfill development, irrespective of its location, and thus will not be addressed specifically for each site. The underlying assumptions for GHGs are:
• The waste being transported to the individual sites, under any scenario considered for this study, would be landfilled. This study does not compare landfilling against any other waste disposal technologies. • Waste would be delivered to the landfill site in purpose built containers via truck or waste transport ship, and on site, purpose-built vehicles would handle these containers. • The landfill gas collected from the landfill would be utilised to generate heat for the leachate treatment process, as well as for electricity generation for on-site uses. • Any landfill gas not utilised for heat or electricity generation would be destroyed within the landfill gas flaring system.
4.3.6 GHG emissions associated with different transportation modes and routes will, however, be qualitatively considered. Where there is the potential for off-site use of this would also be considered on a site-by-site basis.
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Land Contamination 4.3.7 Land contamination is not considered a major issue within this assessment as any minor amounts of contamination that may be encountered on the chosen site / sites can be disposed of, or used within the landfill. As this would not be an important, decision-making issue, it is not addressed further within this SEA. Detailed assessment of contamination issues at preferred sites may be made during future more detailed studies. Marine sediment contamination is however an issue that is considered under the water quality section. Landfill Aftercare and Afteruse 4.3.8 It is assumed that any new or extended landfill would have a comprehensive aftercare system put in place contractually that would last for 20-30 years. This being the case, aftercare impacts are assumed to be managed and are thus not a major consideration within this SEA. In addition, potential aftercare impacts would be subject to separate environmental assessment at an appropriate time when the landfill(s) cease to receive waste, and when the afteruse (if any) of the landfill is known.
Balance of Materials 4.3.9 Impacts associated with the balance of construction and demolition (C&D) materials (particularly public fill) are likely to vary depending on the nature of the site developed, (i.e., land based or marine based) as well as external factors affecting the supply and demand of public fill across Hong Kong and therefore the opportunities for use of public fill arising from other projects. 4.3.10 New sites and extensions can be divided in to those that are land based or marine based. Marine sites are characterised by their need for some form of reclamation and can include: • Extension sites formed as coastal reclamation (e.g. adjacent to existing shoreline). • Extension sites involving a land based filling. • New sites formed by land based filling. • New sites formed by the reclamation of an artificial island.
4.3.11 For both land and marine sites, public fill is a valuable resource for landfill development as it is necessary for engineering fill and daily cover during landfilling operations. 4.3.12 In general terms, as a result of excavation to form void space, land based sites result in the generation of public fill that can match the on-site demand for landfill development given sufficient area within the footprint for temporary stockpiling. For marine sites, reclamation to form the site on which the landfill is subsequently developed would require the importation of filling material (assumed to be inert C&D material supplied through the SAR’s network of public filling areas/public fill barging points) 4.3.13 The EPD “Study on the Waste Management Plan : Collection and Forecast of Waste Data”, Agreement FP 99-055 DFR July 2000, (C&FWD Study) has identified that the amount of public fill generated in the SAR would continue to increase. Therefore, for the purposes of this SEA it is assumed that: • A land based site would meet its own requirements for fill materials with no net surplus or deficit. • A marine based landfill (i.e. an artificial island) would provide a “sink” for the projected surplus of public fill material arising across Hong Kong. This would reduce the need to stockpile surplus fill within Hong Kong and would indirectly contribute to the reduction of C&D materials public fill being sent to existing landfill sites.
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4.3.14 At the project level, a balance of materials, with no net requirement for either import or export of materials is generally considered the optimal situation in terms of negating environmental impacts. However, as noted above there is a projected surplus of public fill across Hong Kong which would need to be managed. Notwithstanding the potential for secondary environmental impacts, from a strategic perspective, a landfill extension or new site that provides a sink for surplus C&D materials is considered to have greater overall environmental benefits.
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5. ENVIRONMENTAL IMPACTS AND EVALUATION CRITERIA 5.1 Introduction 5.1.1 This Section identifies the potential environmental impacts that may arise from the construction and operation of new landfill sites and extension options. Given the likely phased approach to construction of any new site/extension, it is envisaged that construction and operation would be carried out simultaneously. Following initial development of void space, landfilling can commence in tandem with the construction of the environmental control measures and preparation of the next phase of void space. 5.1.2 Environmental legislation and controls affecting the proposals are identified and the evaluation criteria for each environmental sub-criterion are introduced. This Section also identifies typical environmental protection measures (applicable to all sites) that may be recommended to reduce overall impacts. 5.2 Air Quality Introduction 5.2.1 The geographical extent of air quality impacts has been considered up to 500m from the new site/landfill extension operations as well as up to 500m from a line source of vehicular traffic, where road delivery is employed. In addition, the total emission of air pollutants associated with the transportation of waste has been considered in terms of the mode of transport and the distance travelled to each site. 5.2.2 The reclamation / landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition. • Gaseous emissions from vehicles (road and marine) transporting waste during operation.
Government Legislation and Standards 5.2.3 In this Study, reference has been made to the Hong Kong Planning Standards & Guidelines (HKPSG), the Environmental Impact Assessment Ordinance (EIAO) and the associated Technical Memorandum (EIAO-TM). 5.2.4 The main legislative instrument to control air quality within Hong Kong is the Air Pollution Control Ordinance (APCO), Cap. 311, and its subsidiary regulations. Potentially relevant parts of the Ordinance include: • Air Pollution Control (Dust and Grit Emission) Regulations. • Air Pollution Control (Smoke) Regulations. • Air Pollution Control (Specified Processes) Regulations. • Air Pollution Control (Open Burning) Regulation. • Air Pollution Control (Construction Dust) Regulation.
5.2.5 Whilst not directly applicable to landfills, Chapter 9 of the HKPSG recommends suitable buffer distances between small-scale community-based polluting uses and sensitive receivers. Examples of recommended buffers are given in Table 5.1:
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Table 5.1 : HKPSG Recommended Buffer Distances for Land Uses
Polluting Uses Sensitive Uses Buffer Distance Odour sources Sensitive uses 200m Dusty uses Sensitive uses 100m
Air Sensitive Receivers 5.2.6 According to the EIAO-TM, Air Sensitive Receivers (ASRs) include (but are not limited to) any domestic premises, hotel, hostel, hospital, clinic, nursery, temporary housing accommodation, school, educational institution, office, factory, shop, shopping centre, place of public worship, library, court of law, sports stadium, or performing arts centre. 5.2.7 Any other premises or place with which, in terms of duration or number of people affected, has a similar sensitively to the air pollutants as the premises or place is also be considered to be a sensitive receiver.
Generic Air Quality Mitigation 5.2.8 Good site practice would include reduction of dust and odour by: • Paving and subsequent regular sweeping of long-term haul roads within the site. • Regular dampening of unpaved roads. • Vehicle washing (both body wash and wheel wash) before leaving site. • Immediate cover to odorous waste, eg. sludge, after disposal • Daily covering of the current tipping face with inert material (e.g. selected construction and demolition material, tarpaulin covers, foam spray, etc.). • Interim cover of any operational areas which are not currently in use. • Design of enclosed-loop leachate collection / management system; • Proper design, operation, management and maintenance of landfill gas combustion facilities to ensure destruction of odorous organic compounds.
Evaluation of Air Quality Impacts 5.2.9 The evaluation criteria for assessing air quality impacts are shown in Table 5.2. These criteria will be applied to each site on a qualitative basis taking into account known parameters and conditions that could result in relative improvement or exacerbation of impacts.
Further Assessment within SEA 5.2.10 Following the above process to identify the likelihood of impacts occurring, a qualitative and/or semi-quantitative assessment has been carried out where significant air quality impacts are considered possible. 5.2.11 Where the potential for cumulative air quality impacts has been identified, a qualitative assessment of the likely impacts has been carried out (taking into account ambient conditions), whilst recognising the potential for significant changes in baseline conditions (i.e. new developments) by the time the landfill site is developed.
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5.2.12 In addition to local impacts upon identified ASRs, more widespread impacts upon air quality may arise from the transport of waste from the refuse transfer stations to a landfill site. The total emissions of air pollutants from this source contribute to the general air quality patterns of Hong Kong. These have been addressed qualitatively, in terms of both the mode of transport used to convey waste (i.e. marine vessel or road-based refuse collection trucks) and the overall round-trip distances that must be travelled to reach the various landfill sites. Whilst actual emissions associated with the two modes of transport would vary depending upon fuel, engine type etc. for the purposes of this SEA, it is assumed that overall, air quality impacts arising from marine transport are lower than those which would arise by truck as marine vessels can carry almost 100 times more waste thereby allowing significant economies of scale.
5.2.13 For the air quality assessment, developments that emit TSPs, NOx, CO, SO2, which could add to the emissions from the landfill, have been considered within 5km from the emission source (i.e. the landfill). 5.2.14 Following the cumulative assessment of likely air quality impacts, an assessment has been made as to whether impacts are likely to comply with the EIAO and the EIAO-TM, or whether air quality exceedances are likely. This has been carried out by reference to previously endorsed EIAs. By reviewing endorsed EIAs, potential impacts of emissions from the proposed landfills have been reviewed against quantitative data (from comparable studies) to further substantiate the potential for significant air quality impacts.
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Table 5.2: Air Quality Evaluation Criteria
Criteria Score Construction / Operation 1 Distance to areas of air O >500m sensitive land use O 500-100m (if <10 properties affected) - 500-100m (if >=10 properties affected) - <100m (if <10 properties affected - - <100m (if >=10 properties affected) 2 Presence of topographic + High hills between LF and ASRs features which could decrease O Low hills between LF and ASRs or exacerbate local impacts - Flat land between LF and ASRs - - Air shed may trap Air from LF 3 Occurrence of meteorological + Prevailing wind blows from ASRs towards LF conditions which could O No prevailing wind exacerbate impacts - Prevailing winds blow from LF towards ASRs 4 Cumulative impacts of relevant O No additional relevant emissions within 5km emissions (TSP (construction), - Relevant emissions present within 5km NOx, CO, SO2 – LFG Flare) (AQOs unlikely to be exceeded) taking into account ambient conditions Relevant emissions present within 5km - - (AQOs likely to be exceeded on occasions) 5 Total Emissions of Air O Primarily by sea, accumulated distance to be Pollutants from the territory- travelled < 300km wide waste transportation O/ - Primarily by sea, accumulated distance to be between the RTSs and the travelled ≥ 300km but < 400km Site Primarily by sea, accumulated distance to be - travelled ≥ 400km or by sea & road (combined) - - Primarily by road
6 Overall impact O Neutral - Negative – Low - - Negative – High
Note: For criterion 1: The upper bound distance of 500m has been selected, as it is the Study area for air quality assessments commonly adopted for project level EIAs. The lower distance of 100m has been selected as it minimum buffer distance recommended in the HKPSG. For criterion 5: The benchmark distances selected to differentiate between scores are derived from the Preliminary Marine Review for the Study. The range of distances for marine transport is between 200 – 500km. Distances travelled were divided around the “average” (i.e., ~350km), with the average taken as any distance between 300 and 400km (scored as “o/-“). From this basis, benchmarks of 300km and 400km were derived that were scored lower (i.e., “o”) and higher (i.e., “-“) respectively. The rationale for assigning “- -” for road transportation is on the basis that marine vessels can carry almost 100 times more waste than a truck, and so the total emissions per unit waste transported will be greatest for waste transported “primarily by road”.
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5.3 Noise Introduction 5.3.1 The geographical extent of noise impacts would typically be local, extending a radius of around 300m from any land based landfill extension operations as well as a 300m radius from a line source of vehicular traffic, where road delivery is employed. For marine based sites, noise from transportation is not considered to be a key concern as all such sites have been located away from existing land based Noise Sensitive Receivers (NSRs). 5.3.2 Operations are likely to involve noise-generating plant and machinery with the potential to impact directly upon statutory noise limits for adjacent NSRs and indirectly upon habitats of conservation importance through disturbance. 5.3.3 There would be potentially noisy operations occurring at the landfill site during:
• Construction – from the delivery of filling material and other construction materials, placing fill material, piling works and general construction activities. • Operation – from the use of heavy plant, marine vessels (for marine based sites), the waste reception area, pumping plant, etc.
5.3.4 Despite any description or assessment made in this Report on construction noise aspects, there is no guarantee that a Construction Noise Permit (CNP) will be issued for the project construction. The Noise Control Authority will consider a well-justified CNP application, once filed, for construction works within restricted hours as guided by the relevant Technical Memoranda issued under the NCO. The Noise Control Authority will take into account of contemporary conditions/situations of adjoining land uses and any previous complaints against construction activities at the site before making a decision in granting a CNP. Nothing in this Report binds the Noise Control Authority in making a decision. If a CNP is to be issued, the Noise Control Authority will include in it any conditions he thinks fit. Failure to comply with any such conditions will lead to cancellation of the CNP and prosecution action under the NCO. 5.3.5 It is possible that, during construction and operation, activities could continue into, or even through, the night-time period. This would need to be confirmed once the potential for noise impacts are agreed.
Government Legislation and Standards 5.3.6 The following noise related legislation has been considered: Construction Phase 5.3.7 Technical Memoranda on: • Noise from Percussive Piling (PP-TM). • Noise from Construction Work Other Than Percussive Piling (GW-TM). • Noise from Construction Work in Designated Areas (DA-TM). • British Standard BS 5228.
Operational Phase 5.3.8 For noise emanating from the landfill during the operational phase, the noise level should be kept to within the criteria stated in the EIAO-TM. 5.3.9 With regards to road traffic noise, it is recommended that noise levels are kept below 70 dB(A), L10, 1 hour for residential areas and 65 dB(A), L10, 1 hour for education facilities as according to the EIAO-TM. The assessment of the traffic noise should follow the procedures given in the UK Department of Transport document “The Calculation of Road Traffic Noise”.
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Noise Sensitive Receivers 5.3.10 The potential noise sensitive receivers include, but are not limited to, the following:
• Residential Uses (all domestic premises including temporary housing). • Institutional Uses. − educational institutions (including kindergartens and nurseries). − hospitals / medical clinics. − homes for the aged / convalescent homes. − places of public worship. − libraries. − courts of law. − performing arts centre. − auditoria / amphitheatres. • Others. − hostels. − country parks.
Generic Noise Mitigation 5.3.11 The degree to which noise impacts can be mitigated would vary depending on the location and nature of the noise source in relation to the sensitive receivers. In general, noise impacts from site areas, are likely to be more easily mitigated due to the fact that the areas are contained and there is greater flexibility in terms of constructing temporary bunds etc. As they are off-site, impacts arising from vehicles using haulage routes may be less easy to mitigate through simple techniques described for on-site activities. In the event that noise levels are found to exceed standards, possible noise mitigation measures as per Annex 13 S.6 of EIAO- TM, for example noise barriers, may be required for affected sensitive receivers. 5.3.12 During both construction and operation, any necessary overnight activities should be assessed on a case-by-case basis to evaluate their overall noise impact. During the operation and aftercare of the landfill, noise will be generated from the plant and machinery required to manage leachate and landfill gas, such as:
• Leachate treatment works. • Landfill gas extraction system. • Thermal Oxidiser (Flare). • Electricity Generators (Landfill Gas GenSets).
5.3.13 Mitigation can be applied through acoustic shielding in the specification and through verification by modelling and monitoring. All of the strategic landfills and most of the restored landfills in Hong Kong use the plant and equipment listed in Section 5.3.12, and all have been shown to operate within the requirements of the NCO.
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Evaluation of Noise Impacts 5.3.14 The evaluation criteria for assessing noise impacts are shown in Table 5.3. These criteria will be applied to each site on a qualitative basis taking into account known parameters and conditions that could result in relative improvement or exacerbation of impacts.
Table 5.3 : Noise Evaluation Criteria
Criteria Score Construction / Operation 1 Distance to areas of noise O >300m sensitive land use O 100-300m (if <10 properties affected) - 100-300m (if >=10 properties affected) - <100m (if <10 properties affected) - - <100m (if >=10 properties affected) 2 Topographic features + High hills block line of sight between LF & NSRs (only applicable if there are O Low hills block line of sight between LF & NSRs NSRs within 300m) - Line of sight between LF & NSRs - - Line of sight + reflective source between LF & NSRs 3 Cumulative impacts of O No additional noise sources within 300m developments within 300m - Minor noise sources within 300m - - Major noise sources within 300m 4 Overall impact O Neutral - Negative – Low - - Negative – High
Note: The upper bound distance of 300m has been selected, as it is the Study area for noise impact assessments commonly adopted for project level EIAs
Further Assessment within SEA 5.3.15 Following the above process to identify the likelihood of impacts occurring, a qualitative and/or semi-quantitative assessment has been carried out where significant noise impacts are considered possible. 5.3.16 Where the potential for cumulative noise impacts has been identified, a qualitative assessment of the likely impacts has been carried out, whilst recognising the potential for significant changes in baseline conditions (i.e. new developments) by the time the landfill site is developed. For the noise assessment, the cumulative impacts of noise sources within 300m of the landfill have been considered. 5.3.17 Following the cumulative assessment of likely noise impacts, an assessment has been made as to whether impacts are likely to comply with the EIAO and the EIAO-TM, or whether noise exceedences are likely. This has been carried out by reference to previously endorsed EIAs. By reviewing endorsed EIAs, potential noise impacts emanating from the proposed landfills have been reviewed against quantitative data (from comparable studies) to further substantiate the potential for significant noise impacts.
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5.4 Water Quality Introduction 5.4.1 During construction, impacts would principally arise from extensions of coastal landfill sites or the development of artificial island sites. During landfilling operations and the aftercare the principal source of impact would be from uncontrolled releases of leachate. 5.4.2 The geographical extent of potential water quality impacts would vary depending upon the receiving waters and the proximity of the new landfill site / landfill extension to those water bodies. Potential impacts include breaches of Water Quality Objectives (WQO) and limits for discharges as well as potential impacts on beneficial uses. Impacts upon sites of ecological and fisheries importance are addressed separately. 5.4.3 The reclamation / landfill development has the potential to cause the following water quality impacts: • Sediment transport during the site-formation phase. • Sediment laden run-off entering the water during the landfill construction / operation phase. • Leachate discharges from the leachate treatment plant. • Accidental discharges from liquids / material stored on site.
5.4.4 A major reclamation would need to be carefully controlled and appropriate mitigation measures specified to ensure water quality impacts during construction were minimised. In particular the possible “disturbance” of seabed sediments and the suspension of sediments would need to be controlled. 5.4.5 The construction of an artificial island could affect hydrodynamics and cause changes to currents and flow velocities; and in certain instances potentially change the flushing characteristic of key channels around Hong Kong Waters. Generalised patterns of currents in Hong Kong waters are shown in Figure 5.1. 5.4.6 On the basis of experience gained from existing landfills, the assumption is made that for an operating landfill all site-based discharges would be controlled, so that the risk of associated water quality impacts during operation can be managed to acceptable levels. However, this assumption should be addressed in further detail, including a risk assessment (e.g. of a leachate breakout incident) during the detailed EIA stage of the project. The design of the landfill would have to incorporate environmental protection orientated designs to cater for such potential incidents.
Government Legislation and Standards 5.4.7 The SEA has taken into account the following relevant Hong Kong legislation:
• Water Pollution Control Ordinance (Cap. 358). • Water Pollution Control (General) Regulations. • Water Pollution Control (Sewerage) Regulations. • Water Quality Objectives (WQO). • EIAO and EIAO-TM.
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Water Quality Sensitive Receivers 5.4.8 Ecological and fisheries issues, with respect to water quality, are considered in Sections 5.6 and 5.7 respectively. Existing or potential beneficial uses in Hong Kong (excluding ecological /fisheries receivers) include, but are not limited to : • Areas for abstraction of water for potable water supply. • Water abstraction for irrigation and aquaculture. • Beaches and other recreational areas. • Water abstraction for cooling, flushing and other industrial purposes. • Areas for navigation/shipping including typhoon shelters, marinas and boat parks.
5.4.9 In addition, given the nature of impacts on water quality, potential impacts on identified sensitive receivers in Chinese Waters are also subject to consideration. 5.4.10 Detailed locations and nature of the water sensitive receivers are tabulated in Table 3.1 and shown in Figure 3.1 and 3.2 of the Water Quality and Hydrodynamic Assessment Report. Extracts are shown in Appendix I. Locations of EPD routine sediment and water quality monitoring stations are shown in Figure 5.2.
Generic Water Quality Mitigation 5.4.11 For artificial island sites, mitigation is likely to be required to avoid impacts associated with sediment releases and transport within the water column through dredging, and/or filling activities. The proposed method of construction described in Section 3.2 has been developed to minimise the potential for construction related sedimentation of the water column, by providing a sheltered area for construction behind the outer seawall which faces predominant wind and wave action. As is customary, mitigation measures should be specified in terms of construction procedures, which define the location, rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood). 5.4.12 If significant impacts are anticipated for those marine sites that require dredging and filling, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments. In addition, a floating boom should be used to control the spread of any flotsam and also reduce the dispersal of any litter within public fill. 5.4.13 During construction, sediment-laden runoff from site can be controlled by installing settlement tanks, which allow sediments to settle prior to discharge. Run-off would be generated during periods of high rainfall and so the temporary surface water drainage works and settlement tanks would need to be sized according to the works. 5.4.14 During operation, the surface water drainage system should be designed to intercept stormwater, channel it away from active areas and discharge it as clean water from the site. Any stormwater that enters the active area and thereby becomes contaminated will be considered leachate and diverted to the leachate treatment plant. 5.4.15 To accommodate the unforeseen event of leachate breakout, from completed areas, provision should be made in the design to enable sections of the surface water drainage channels to be isolated in order to trap any leachate before it escapes from the site.
Evaluation of Water Quality Impacts 5.4.16 The evaluation criteria for assessing water quality impacts are shown in Table 5.4. Both qualitative and quantitative assessment approaches would be employed in the evaluation of water quality impacts.
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Table 5.4 : Water Quality Evaluation Criteria
Criteria Score Construction / Operation 1 Watercourse diversion O No diversion necessary - Minor diversion (e.g. to man-made channel / nullah) - - Major diversion (e.g. to natural river) 2 Potential for sediment O Area not contaminated / No dredging required contaminant release - Minor contamination present - - Major contamination present 3 Potential impacts on WSRs O Pollutant levels less than WQOs (including increase or - <10% exceedance of WQOs exceedance of WQOs) (minor mitigation measures required) - - >10% exceedance of WQOs (major mitigation measures required) 4 Potential impacts on O No groundwater issues / aquifer groundwater - Minor aquifer present - - Major aquifer present 5 Potential cumulative impacts O Low (potential for concurrent - Medium projects to exacerbate preceding impacts) - - High 6 Overall impact O Neutral - Negative – Low - - Negative – High
Note: Criterion 3 is a quantitative output from hydrodynamic modelling exercise.
Further Assessment within SEA 5.4.17 Water quality impacts associated with land based sites are, in general, relatively simple and the magnitude of impact is relatively small provided that there is proper implementation of on- site pollutant control measures. Qualitative analysis would be sufficient to identify the nature and magnitude of potential impacts. Consequently, a qualitative approach has been employed for the water quality impact assessment of land based sites. 5.4.18 For marine based sites, the assessment of water quality impacts is more complex, since the magnitude of impact could be significant. For this reason, water quality impacts for marine based sites have been assessed quantitatively using the Delft 3D hydrodynamic computer model, as well as by qualitative means. 5.4.19 The Delft 3D model is capable of accurately simulating the stratified conditions and salinity transport within the modelled area. Cumulative impacts due to other concurrent projects, activities or pollution sources that might affect marine waters and sensitive receivers have been identified and incorporated into the model. 5.4.20 The modelling results have been assessed for compliance with Water Quality Objectives at selected sensitive receivers for respective sites. Daily sedimentation rate has been modelled and results have been incorporated into the ecological and fisheries assessments as appropriate. Further details of the modelling methodology are shown in Appendix I.
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5.5 Waste Management / Materials Balance Introduction 5.5.1 Impacts associated with the management of wastes and the balance of fill material may arise during the construction and landfilling operations. The principal source of waste arisings would be during the landfill construction phase. 5.5.2 Specific issues affecting the nature of impacts associated with public fill have been outlined in Section 3.5. For both land and marine sites, public fill is a valuable resource for landfill development as it is necessary for engineering fill and daily cover. 5.5.3 In general, land based sites result in the generation of material that can match the on-site demand for landfill development. For marine sites, reclamation for the construction of the platform on which the landfill would subsequently be developed would require additional fill material. 5.5.4 For the construction of an artificial island, inert C&D materials would be brought in from a network of barging points within the SAR, and the assumption is made that this would generally be public fill (except for some of the edge protection and other built infrastructure). Whilst this material would be sorted and selected prior to transfer to the site, some litter materials can be expected in the material. Various options for construction have been considered, the current strategy has minimised the need for dredging for all sites. In the event that a scheme is pursued which involves a limited amount of dredging, these excavated muds could be disposed of within the area to be reclaimed with public fill, thereby limiting the need for transport and disposal elsewhere. During operation daily cover requirements could be sourced from incoming C&D material. 5.5.5 For a land based site, the aim has been to ensure a balance of cut and fill requirements during construction, i.e., no net import or export of fill materials. Because of this, there is limited use of public fill during the construction phase, although during operation daily cover requirements could be sourced from incoming C&D material. Greenhouse Gas Emissions as a Function of Mode of Waste Transport 5.5.6 As stated in paragraph 4.3.6, the GHG emissions associated with different waste transportation modes and routes will be qualitatively considered. The basis for this assessment would be the average mass of GHG released per kilogram of fuel used to transport the waste :
Table 5.5 : Road Transport – US Diesel Vehicles
US Heavy Duty Diesel Vehicles (Advanced Control; Assumed Fuel Economy: 2.4km/litre (41.7 l/100km)
Parameter CO2 CH4 N2O Average (g/km) 987 0.04 0.025 Average (g/kg fuel) 3,172 0.14 0.08
Source: Revised 1996 IPCC Guidelines Reference Manual; Table 1-32; page 1.75.
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Table 5.6 : Road Transport – European Diesel Vehicles
European Diesel Heavy Duty Vehicles (Moderate Control; Assumed Fuel Economy: 3.3km/litre (29.9 l/100km)
Parameter CO2 CH4 N2O (g/km) 770 0.06 0.03 (g/kg fuel) 3,140 0.2 0.1
Source: Revised 1996 IPCC Guidelines Reference Manual; Table 1-39; page 1.82.
Table 5.7 : Freight Road Mileage Conversion Factors
Diesel Truck Type CO2 (g/km) Articulated 938 Rigid 1,072
Source: UK DEFRA Environmental Reporting - Guidelines for Company Reporting on Greenhouse Gas Emissions July 2001, (Annex 6 – Transport Conversion Tables – Table 10)
Table 5.8 : Marine Transport – Non-Ocean Going Vessels
Boats
Parameter CO2 CH4 N2O (g/kg fuel) 3,188* 0.23 0.08
Source: Revised 1996 IPCC Guidelines Reference Manual; Table 1-47; page 1.89.
Note: * This CO2 generation figure of 3,188 g/kg fuel utilised is supported by information in “Wright A.A., Effective Marine Exhaust Emission Controls, Lloyd’s Register of Shipping (1996).
5.5.7 It should be noted that waste transferred from the transfer stations to the landfills is done so by special-built refuse transfer vessels. The above-mentioned CO2 factor is a function of marine oil fuels which all have essentially the same carbon content (85.0 – 87.5%) and generate the 3,188g of CO2 per every kg of fuel consumed. 5.5.8 From Tables 5.5 to 5.8, it can be seen that the average mass of GHG released per kilogram of fuel used is similar, whether the transportation is by road vehicle or marine vessel. However, the economies of scale between a road vehicle transporting one container and a marine vessel transporting, say, 100 containers is obvious. Therefore, the assessment would be based on the premise that is more beneficial, in terms of GHG emission, to transport waste by marine vessel than by road.
Government Legislation and Standards 5.5.9 The following legislation covers, or has some bearing upon, the handling, treatment and disposal of wastes:
• EIAO and EIAO-TM • Waste Disposal Ordinance (Cap 354). • Waste Disposal (Chemical Waste) (General) Regulation (Cap 354). • Public Health and Municipal Services Ordinance (Cap 132) - Public Cleansing and Prevention of Nuisances Regulation. • Dumping at Sea Ordinance (1995).
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Generic Waste Management Mitigation 5.5.10 The principal approach to waste management is to achieve a materials balance or alternatively provide a valuable sink for excess C&D materials. This will require detailed consideration of generation rates and timing of materials arisings (particularly for marine sites), to avoid negative impacts. 5.5.11 For artificial island sites to be constructed using public fill, a silt curtain may be installed around the immediate works area to prevent dispersion of silt and other fines during filling activities. In addition, a floating boom should be used to control the spread of any flotsam. 5.5.12 Various potentially polluting materials may be stored, handled and transported to / from the island site. Examples may include leachate, chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site. All waste materials would need to be stored, handled and transported in an agreed and appropriate manner that complies with the Waste Disposal Ordinance (Cap 354) and subsidiary regulations such as the Waste Disposal (Chemical Waste) (General) Regulation. For this assessment it is assumed that potential impacts from dangerous goods would be controlled through appropriate designs and management systems.
Evaluation of Waste Impacts 5.5.13 The evaluation criteria for assessing waste impacts are shown in Table 5.9. These criteria will be applied to each site on a qualitative basis taking into account known parameters and conditions that could result in relative improvement or exacerbation of impacts.
Table 5.9 : Waste Management Evaluation Criteria
Criteria Score Construction / Operation 1 Balance of materials + Public fill required for landfill development, assuming overall surplus of public fill in Hong Kong (surplus / deficit of public fill needed for landfill O Materials balance development) - Virgin materials required / Surplus of material 2 GHG emissions by mode of O Primarily by sea, accumulated distance to be transport for delivery of waste travelled < 300km to the site from RTSs O/ - Primarily by sea, accumulated distance to be travelled ≥ 300km but < 400km
Primarily by sea, accumulated distance to be - travelled ≥ 400km or by sea & road (combined) - - Primarily by road
3 Overall impact + Positive O Neutral - Negative – Low - - Negative – High
Note: For criterion 2: The benchmark distances selected to differentiate between scores are derived from the Preliminary Marine Review for the Study. The range of distances for marine transport is between 200 – 500km. Distances travelled were divided around the “average” (i.e., ~350km), with the average taken as any distance between 300 and 400km (scored as “o/-“). From this basis, benchmarks of 300km and 400km were derived that were scored lower (i.e., “o”) and higher (i.e., “-“) respectively. The rationale for assigning “- -” for road transportation is on the basis that marine vessels can carry almost 100 times more waste than a truck, and so the total emissions of greenhouse gases per unit waste transported will be greatest for waste transported “primarily by road”.
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Further Assessment within SEA 5.5.14 Following the above process to identify the likelihood of waste impacts occurring, a qualitative and/or semi-quantitative assessment has been carried out where significant waste management impacts are considered possible. 5.5.15 Where the potential for cumulative waste impacts has been identified, a qualitative assessment of the likely impacts has been carried out, whilst recognising the potential for significant changes in waste production (e.g. by the time the landfill site is developed). For the waste assessment, the cumulative impacts of public fill and marine mud generation across the SAR have been considered in consultation with CED’s Fill Management Division (FMD). 5.5.16 Following the cumulative assessment of likely waste impacts, an assessment has been made as to whether impacts are likely to comply with the EIAO and the EIAO-TM. This has been carried out by reference to previously endorsed EIAs and FMD’s register of projects and by use of professional judgement. By reviewing endorsed EIAs, potential waste impacts arising from proposed landfills have been reviewed against quantitative data (from comparable studies) to further substantiate the potential for significant waste impacts. 5.6 Ecology Introduction - Terrestrial / Freshwater Ecology 5.6.1 The principal source of impact on terrestrial resources would be during the landfill construction phase arising from habitat loss and potential severance within and immediately adjacent to the footprint of the new landfill site / landfill extension area. There is also potential for direct, localised noise and visual disturbance impacts upon nearby species and communities. Disturbance of adjacent species and communities may also potentially occur during landfill operation, although such impacts should be avoidable / readily controllable through extension of existing landfill management measures that have been demonstrated to be effective in Hong Kong.
Introduction - Marine Ecology 5.6.2 The principal source of impact on marine resources would be during the landfill construction phase from the loss and disturbance of benthic habitat within and adjacent to the footprint of the landfill new site / extension area. The extent of benthic habitat smothering from sediment dispersal from dredging (as may be required) and reclamation activities is a function of water column depth and site-specific hydrodynamic patterns. As such, the spatial extent of aquatic ecology impacts has been quantified based on the outcome of the numerical modelling exercise that has been conducted for the water quality assessment for all marine sites. 5.6.3 Sediment plume formation / dispersal will induce a decline in dissolved oxygen levels in the water column that may lead to impacts upon less mobile species (fish larvae) and sessile benthic species in particular. The quality of disturbed sediment will also be significant in terms of mobilising and increasing the bio-availability of adsorbed contaminants as may be relevant. 5.6.4 The presence of marine mammals throughout the HKSAR’s marine waters requires that attention be given to potential physical (vessel collision) and noise impacts during site construction and operation.
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Government Legislation and Standards 5.6.5 The following Hong Kong SAR Government legislation and guidelines are relevant for the SEA : • EIAO and EIAO-TM • Forests and Countryside Ordinance (Cap. 96), • Wild Animals Protection Ordinance (Cap. 170), • Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187) • Town Planning Ordinance (Cap. 131), • Country Parks Ordinance (Cap. 208); and • Marine Parks Ordinance (Cap. 476) and associated subsidiary legislation.
5.6.6 In addition, the Study makes reference to the following Technical Memoranda, Technical Circular and Guidelines for guidance on conservation, impact assessment and mitigation : • "Guidelines for Implementing the Policy on Off-site Ecological Mitigation Measures" (PELB Technical Circular 1/97, Works Branch Technical Circular 4/97, • Hong Kong Planning Standards and Guidelines: Chapter 10, "Conservation",
5.6.7 This Study also takes note of the following relevant international agreements :
• Convention on Wetlands of International Importance Especially as Waterfowl Habitat ("Ramsar Convention"). • Convention on the Conservation of Migratory Species of Wild Animals ("Bonn Convention"). • Convention on International Trade in Endangered Species of Wild Fauna and Flora ("CITES"). • Convention on Biological Diversity (“Rio Convention”).
Ecologically Sensitive Receivers 5.6.8 The following Protected Areas / Recognised Sites Of Conservation Importance are considered ecologically sensitive receivers : • Existing or gazetted proposed Special Areas. • Existing or gazetted proposed Country Parks. • Existing or gazetted proposed Marine Reserves. • Existing or gazetted proposed Marine Parks. • Restricted Areas listed under the Wild Animals Protection Ordinance Chapter 170; • Sites of Special Scientific Interest. • The Mai Po & Inner Deep Bay Ramsar Site, and associated Wetland Conservation Area (WCA) and Wetland Buffer Area (WBA). • Any other declared by the Government as having special conservation importance.
5.6.9 Using Annex 8 of the EIAO-TM as a guide, further ecological assessment would be recommended if the proposed development is likely to affect any one of the following important habitats: • Terrestrial / Freshwater – Mature native woodland, freshwater/brackish marshes and natural stream courses/rivers. • Marine / Coastal – Undisturbed natural coast, inter-tidal mudflats/established mangrove stands, established sea-grass beds and established coral communities.
It should be noted that the list of habitat types above for which more detailed ecological assessment may be required is not exhaustive.
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5.6.10 Further ecological assessment has been recommended if the proposed development is likely to affect habitats supporting significant populations of wild fauna or flora that are Species of Conservation Importance: • Listed in IUCN Red Data Books or those of the South China region. • Listed in international conventions for conservation of wildlife. • Endemic to Hong Kong or South China. • Listed under local legislation, or • Considered as rare in the SAR or having special conservation importance by scientific studies other than those listed above.
Generic Ecological Mitigation 5.6.11 The application of measures for noise and water quality can be applied to mitigate impacts on marine ecology, whilst air quality and visual impact control measures (particularly fugitive dust control) can also be applied for terrestrial resources. 5.6.12 Mitigation measures designed to minimise impacts to the seasonal population of marine mammals include restrictions on vessel speed and the use of bubble curtains during any underwater percussive piling work for marine structures such as jetties. Other mitigation measures designed to mitigate impacts to water quality to acceptable levels (compliance with WQOs) would also mitigate impacts on marine ecological resources. 5.6.13 Whilst not considered to be a mitigation measure, ecological enhancement measures can be applied to marine based sites. A number of reclamation design features, such as rubble mounds, armour rock or concrete armour edge protection would have consequent ecological benefits, facilitating colonisation by intertidal organisms and corals. As an additional habitat enhancement measure, artificial reefs could be deployed adjacent to an artificial island.
Evaluation of Ecological Impacts 5.6.14 The evaluation criteria for assessing ecological impacts are shown in Table 5.10. 5.6.15 The inherent differences in character between terrestrial and marine habitats, particularly with regard to sediment transport and dispersal processes, dictate that the type of ecological impacts on biological resources would differ. Whilst impacts on marine resources are largely felt through a change in water quality and are controlled by hydrodynamic processes, impacts on terrestrial resources may be more diverse but in most cases are also likely to be more localised. As such, it is appropriate that separate evaluation criteria be developed. 5.6.16 There are a number of “wetland habitats” within the HKSAR that, for the purpose of this SEA, may be considered either as terrestrial resources or as marine resources. Under the “Ramsar Convention”, to which the HKSAR Government is a signatory, wetlands includes all fresh, brackish and marine waters to a depth of no greater than 6 metres at low tide. Included with terrestrial resources are all freshwater and brackish wetlands, with all marine and estuarine wetlands (influenced tidal processes) included with the marine resources.
Further Assessment within SEA 5.6.17 Following the above process to identify the likelihood of ecology impacts occurring, a qualitative and/or semi-quantitative assessment has been carried out where significant ecology impacts are considered possible. 5.6.18 Where the potential for cumulative impacts has been identified, a qualitative assessment of the likely impacts has been carried out, whilst recognising the potential for significant changes in baseline conditions by the time the landfill site is developed. For the marine ecology assessment, no specific distance criteria have been applied to determine cumulative impacts as this is subject to specific hydrodynamic patterns that differ greatly between marine sites. As a rule of thumb a distance of 500m has been adopted for terrestrial sites as is commonly used to define the limit of the Study Area for designated EIA projects.
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Table 5.10: Ecological Evaluation Criteria
Criteria Score Construction / Operation Terrestrial Marine 1 Potential for secondary O >500m No impact anticipated environmental impacts on “Areas of Absolute Exclusion” - 100-500m Minor potential for impact - - <100m Major potential for impact Terrestrial Marine 2 Affects an important habitat O 100-500m No impact anticipated - <100m Minor impact anticipated - - landtake Major impact anticipated 3 Affects a species of O No disturbance conservation importance - Minor disturbance - - Major disturbance 4 Potential for cumulative O No / limited potential for cumulative impacts ecological impacts on sites of - Minor potential for cumulative impacts recognised value - - Major potential for cumulative impacts 5 Overall impact O Neutral - Negative – Low - - Negative – High
Notes : 1. Disturbance / disruption includes impacts arising from noise, dust, water pollution (e.g. hydrodynamic / sedimentation); habitat fragmentation and severance etc. 2. All freshwater wetlands are included under “Terrestrial” 3. All marine waters and marine / estuarine wetlands (Ramsar defined) are included under “Marine”
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5.7 Fisheries Introduction 5.7.1 The farming and harvesting of aquatic resources is termed either “aquaculture” (for “land based” confined wetland resources such as shrimp, fish and duck ponds) or “mariculture” (off- shore fish culture zones). Aquaculture activities only occur on a significant scale in the NWNT of Hong Kong and have been considered within the terrestrial ecology assessment (Section 5.6 refers). As such, the fisheries assessment section of the SEA refers only to mariculture and open-sea fisheries. 5.7.2 The principal source of impact on fisheries resources would be during the landfill construction phase through the direct displacement of important fisheries areas or mariculture areas, and from an associated increase in suspended sediment levels (decline in dissolved oxygen) from dredging / reclamation activities. During landfill operation there may also be a decline in water quality induced by hydrodynamic change (i.e. decreased flushing capacity and increased retention time of water quality parameters).
Government Legislation and Standards 5.7.3 Hong Kong SAR Government ordinances and regulations relevant to the consideration of fisheries and mariculture include : • Fisheries Protection Ordinance (Cap. 171) and Regulations aims to promote the conservation of fish and other forms of aquatic life within the waters of Hong Kong and to regulate fishing practices and to prevent activities detrimental to the ‘fishing industry' (preamble). The Ordinance provides for Regulations to prohibit the use of explosives and fish poisons, such substances being listed in the Schedule. The Fisheries Protection Regulations enable enforcement of these prohibitions. • Marine Fish Culture Ordinance (Cap. 353) and associated subsidiary legislation. • Environmental Impact Assessment Ordinance (Cap. 499) and its associated Technical Memorandum (EIAO-TM) that presents criteria for evaluating fisheries impacts (Annex 9).
Fisheries Sensitive Receivers 5.7.4 The following are considered SRs with regard to fishery impacts within the SEA : • Mariculture (gazetted marine fish culture zones). • Spawning / fry nursery areas e.g. mangrove areas. • Oyster beds.
Generic Fisheries Mitigation 5.7.5 The application of measures to maintain appropriate water quality can be applied to mitigate impacts on fisheries resources.
Evaluation of Fisheries Impacts 5.7.6 The evaluation criteria for assessing impacts upon fisheries are shown in Table 5.11. These criteria will be applied to each site on a qualitative basis taking into account the findings of the water modelling exercise for marine sites. For terrestrial sites, the criteria are applied on a qualitative basis taking into account the proximity of aquaculture areas. 5.7.7 The criteria for marine fisheries impact assessment are broadly the same as those for the marine resources as presented in Section 5.6.
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Table 5.11: Fisheries Evaluation Criteria
Criteria Score Construction / Operation 1 Potential for secondary O No impact anticipated environmental impacts on “Areas of Absolute Exclusion” - Minor potential for impact - - Major potential for impact 2 Affects an important O No impact anticipated mariculture/ fisheries - Minor potential for impact resources (including spawning / nursery ground) - - Major potential for impact 3 Potential for cumulative O No / limited potential for cumulative impacts fisheries Impacts on sites of - Minor potential for cumulative impacts recognised value - - Major potential for cumulative impacts 4 Overall impact O Neutral - Negative – Low - - Negative – High
Note: Disturbance / disruption includes impacts arising from water pollution (e.g. hydrodynamic / sedimentation); habitat fragmentation and severance etc.
Further Assessment Within SEA 5.7.8 Where the potential for cumulative fisheries impacts has been identified, a qualitative assessment of the likely impacts has been carried out. For the fishery assessment, cumulative impacts have been considered where the impact of another scheme / development is predicted to affect the same resource(s) as the proposed landfill. 5.7.9 Following the cumulative assessment of likely fisheries impacts, an assessment has been made as to whether impacts are likely to comply with the EIAO and the EIAO-TM. This has been carried out by reference to previously endorsed EIAs and by use of professional judgement. By reviewing endorsed EIAs, potential fisheries impacts arising from proposed landfills have been reviewed against quantitative data (from comparable studies) to further substantiate the potential for significant fishery impacts. 5.8 Cultural Heritage Impacts Introduction 5.8.1 Cultural heritage impacts would primarily occur during the landfill construction phase arising from the destruction of any previously known areas of importance (e.g. areas where significant archaeological finds may have occurred) and any unknown sites of archaeological interest within the footprint of the new landfill or landfill extension area. The potential geographical extent of potential impacts is likely to be localised. There should not be any additional operational impacts. 5.8.2 Whilst Declared Monuments, Graded Historical Buildings and Structures, Deemed Monuments and Archaeological Sites have been identified as “Areas of Absolute Exclusion”, it is possible that during excavations, new sites of archaeological interest may be located. Thus the areas potential value may need to be considered. 5.8.3 There is no quantitative standard for determining the relative importance of sites of cultural heritage, but in general sites of unique, archaeological, historical or architectural should be considered as highly significant.
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Government Legislation and Standards 5.8.4 The EIA Ordinance stipulates that consideration must be given to issues associated with cultural heritage and archaeology as part of the EIA process. Annexes 10 and 19 of the EIAO-TM outline criteria for evaluating the impacts on sites of cultural heritage and guidelines for impact assessment, respectively. 5.8.5 The principal legislation relevant to cultural heritage and archaeological issues is the Antiquities and Monuments Ordinance (Cap 53). Human artefacts, relics and built structures may be gazetted and protected as monuments under this Ordinance. 5.8.6 The Antiquities and Monuments Office (AMO) is responsible for advising the Government on sites that merit protection. The AMO has further responsibility for the protection of buildings, items of historical interest and areas of archaeological significance. The excavation and search for such relics requires a licence under the Ordinance. For archaeological sites, all relics dated prior to 1800AD belong to the Hong Kong Government under the Antiquities and Monuments Ordinance.
Sensitive Receivers 5.8.7 Archaeological sites are administratively classified into three categories, as follows : • Designated – those that have been declared as monuments and are to be protected and conserved at all costs. • Administrative Protection – those which are considered to be of significant value but which are not declared as monuments and should be either protected, or if found not possible to protect these sites then salvaged. • Monitored – those which are of lesser significance or whose potential is not fully assessed which should not be disturbed with the exception of minor works if they are permitted and monitored by AMO.
Generic Cultural Heritage Mitigation Measures 5.8.8 The EIAO-TM identifies a general presumption in favour of the protection and conservation of all sites of cultural heritage, and requires impacts on sites of cultural heritage to be “kept to a minimum”.
Evaluation of Cultural Heritage Impacts 5.8.9 The evaluation criteria for assessing cultural heritage impacts are shown in Table 5.12. These criteria will be applied to each site on a qualitative basis taking in to account known parameters and conditions that could result in relative improvement or exacerbation of impacts. 5.8.10 A fundamental difference between evaluating cultural heritage impacts arising from marine based sites and land based sites, is the greater understanding of the cultural heritage of land areas in Hong Kong. There is still a relatively poor understanding of the marine archaeological potential for most areas of Hong Kong waters. This could potentially lead to a disparity in the subjective evaluation of land based sites and marine based sites. Therefore, for marine based sites, impacts will also be assessed in terms of whether a site has a reasonable potential to yield deposits of archaeological interest, by virtue of known land based activities in their vicinity. 5.8.11 It is also considered that for marine based sites, the absence of existing information does not at this stage preclude it from further investigation. However, it has been requested that any marine based sites investigated further under this project should include a marine archaeological investigation as part of the future studies.
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Table 5.12: Cultural Heritage Evaluation Criteria
Criteria Score Construction / Operation 1 Important cultural O No direct or indirect impacts caused to an important (Declared, Deemed or Graded site. Sites) / archaeological sites - Minor impacts (e.g. potential for vibration impacts to a building or affects the setting surroundings) - - Major direct impact to an important site 2 Potential for archaeological O No / limited potential for archaeological finds value - Minor potential for archaeological finds - - Major potential for archaeological finds 3 Potential for cumulative cultural O No / limited potential for cumulative impacts heritage Impacts on sites of - Minor potential for cumulative impacts recognised value - - Major potential for cumulative impacts 4 Overall impact O Neutral - Negative – Low - - Negative – High
Further Assessment within SEA 5.8.12 Following the above process to identify the likelihood of cultural heritage impacts occurring, a qualitative and/or semi-quantitative assessment has been carried out where significant cultural heritage impacts are considered possible. 5.8.13 Where the potential for cumulative cultural heritage impacts has been identified, a qualitative assessment of the likely impacts has been carried out. For the cultural heritage assessment, cumulative impacts have been considered where the impact of another scheme / development is predicted to affect the same resource(s) as the proposed landfill. 5.8.14 Following the cumulative assessment of likely cultural heritage impacts, an assessment has been made as to whether impacts are likely to comply with the EIAO and the EIAO-TM. This has been carried out by reference to previously endorsed EIAs and by use of professional judgement. By reviewing endorsed EIAs, potential cultural heritage impacts arising from proposed landfills have been reviewed to further substantiate the potential for significant cultural heritage impacts. 5.9 Landscape and Visual Impacts Introduction 5.9.1 The objective of the Strategic Landscape and Visual Assessment is to assess at a broad level, the significance of impacts of each of the proposed landfill new sites / landfill extensions on the existing landscape and visual baseline conditions. 5.9.2 As it is part of a strategic impact assessment, the landscape and visual impact assessment does not include the level of detail specified by the Environmental Impact Assessment Ordinance (EIAO) or its Technical Memorandum. This detailed level of information would be provided at subsequent detailed assessment stage of this project, carried out under other investigations, separate from this Study. The SEA, although at outline level, is sufficiently detailed to ensure that the collection of further detailed information at EIA stage would be unlikely to affect its conclusions.
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Government Legislation and Standards 5.9.3 There is no primary legislation specifically related to landscape and visual impacts in Hong Kong. The assessment of landscape and visual impacts within this SEA broadly follows the guidelines in Annex 18 and Annex 10 of the Technical Memorandum of the EIA Ordinance. 5.9.4 For the purposes of assessing compatibility with landscape planning intention, the following designations are assumed to be relevant to landscape : Territory Development Strategy Review (TDSR)
• Conservation Area - Countryside character with extensive area of high quality natural landscape. No development is envisaged. • Marine Park/Reserve - Countryside character with extensive area of high quality natural landscape. No development is envisaged. • Landscape Protection Area - Countryside character with areas of high quality natural landscape. Presumption against development, but certain compatible uses (e.g. agriculture and some types of recreation) may be considered. • Inshore Water Protection Area - Countryside character with areas of high quality natural landscape. Presumption against development, but certain compatible uses (e.g. some types of recreation) may be considered. • Development Area Countryside - Rural character with areas of scenic quality. Low density development and uses which are compatible with rural character. • Development Area High Landscape Value - Suburban character with areas of scenic quality. Selected but constrained urban/suburban land use". (extracted from “Final Technical Report on TDSR” , 1995, p.40)
Outline Zoning Plan (OZP)
• SSSI - to conserve and to protect fauna and flora and other natural features with special scientific value. • Country Park - to encourage recreation and tourism, protect vegetation and wildlife, preserve and maintain buildings and sites of historical or cultural significance. • Coastal Protection Area - to retain natural coastline. • Conservation Area - to retain existing natural features and rural use. • Green Belt - to define limits of urban development areas by conserving landscape features. (extracted from “Hong Kong Planning Standards and Guidelines, Chapter 10 – Conservation” para 3.3.2.).
Visually Sensitive Receivers 5.9.5 For the purposes of landscape and visual assessment, the following are assumed to be sensitive receivers: Landscape Resources 5.9.6 This includes features such as ; topography; hydrology (water features including areas of sea); vegetation; human features (including settlements, notable buildings or other features). Landscape Character 5.9.7 Landscape character is the aggregate impression or feeling created by the specific combination of landscape resources in a given landscape.
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Visual Sensitive Receivers (VSRs) 5.9.8 Visual sensitive receivers are those people who will view a proposed development. They are classified into four general types: residential, recreational, travelling and working. The sensitivity of receivers to visual impacts is influenced by the immediate context of the viewer, the activity in which they are engaged and the value that they attach to this location in particular. 5.9.9 As data on the precise numbers of VSRs affected at any given location at any given time is not available, the numbers of receivers is estimated on an indicative “order of magnitude” basis, using the terms “very few”, “few”, “many” and “very many”. For example, locations such as small rural settlements might be said to have “very few” VSRs, when compared to an urban area of Hong Kong Island, which might be said to have “very many”. 5.9.10 The Study has also considered VSRs in future developments which are committed, but has not considered those VSRs in developments that are the subject of tentative proposals or feasibility studies (such as the current resort proposals for South Lantau). It may be appropriate to consider VSRs in these latter types of development at full EIA stage, if they have become committed developments. 5.9.11 Residential Receivers - Those who view the scheme from their homes are considered to be highly sensitive to any visual intrusion. This is because the attractiveness, or otherwise, of the view will have a notable effect on a residents’ general quality of life and acceptability of their home environment. VSRs are identified for the purpose of this Study at a broad, aggregate level only. 5.9.12 Recreational Receivers - For those who view the scheme whilst engaging in outdoor leisure pursuits, visual sensitivity varies depending on the type of recreational activity and the amount of time spent in a particular location. Those taking a stroll in a park, for example, would be classified as a high sensitivity group compared to football players who would have a low sensitivity rating. 5.9.13 Working Receivers - Those people who view the scheme from their workplace are considered relatively less sensitive to visual intrusion. This is because they are employed in activities where visual outlook plays a less important role in the perception of the quality of the working environment. They are classified as a low sensitivity group. 5.9.14 Travelling Receivers - For those people who view the scheme from public thoroughfares, the degree of visual intrusion experienced depends on the speed of travel and whether views are continuous or only occasional. Generally, the slower the speed of travel and the more continuous the viewing experience, then the greater the degree of sensitivity.
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Evaluation 5.9.15 The evaluation of landscape and visual impacts comprises four basic parts as set out in Table 5.13 below:
Table 5.13: Landscape and Visual Impact Evaluation Criteria
Criteria Score 'Construction / Operation' and 'Afteruse' 1 Implications for landscape + Positive planning and designations O Neutral/Insubstantial - Negative – Low - - Negative – High 2 Landscape resources + Positive O Neutral/Insubstantial - Negative – Low - - Negative – High 3 Landscape character + Positive O Neutral/Insubstantial - Negative – Low - - Negative – High 4 Visual + Positive O Neutral/Insubstantial - Negative – Low - - Negative – High 5 Overall impact + Positive O Neutral/Insubstantial - Negative – Low - - Negative – High
5.9.16 The specific method of evaluation and assessment for each of these elements is set out below. Implications for Landscape Planning and Designations 5.9.17 A broad review of the landscape planning context is carried and relevant landscape designations are mapped. The compatibility of the proposal with the landscape planning objectives for the study area of each option is then assessed. Compatibility is assessed only against the planning designation that actually covers the site on which the landfill lies. No assessment is made against designations that cover adjacent areas. Impacts on Landscape Resources 5.9.18 Baseline mapping of landscape resources is achieved by site visit (for land based sites) and desk-top study of topographical maps, information databases and photographs. Locations of principal landscape resources are mapped. Resources are identified predominantly on a qualitative, not quantitative, basis.
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5.9.19 The principal elements of the construction works and operational procedures that would cause landscape resource impacts are then identified. (These are outlined in Part A). 5.9.20 A brief overall assessment of the significance of landscape impacts is presented for each option. The significance of impacts is assumed to be a function of the magnitude of the impact and the sensitivity of the landscape resource. Impacts are assessed during construction/operation; during afteruse without mitigation; and during afteruse with mitigation at Year 10. Impacts on landscape resources and landscape character are presented separately. Impacts on Landscape Character 5.9.21 Baseline assessment of landscape character is achieved primarily by site visit (for land based sites) supported by desk-top study of topographical maps, information databases and photographs. Locations of Landscape Character Areas (LCAs) are mapped. LCAs are areas of consistent and homogenous landscape character. 5.9.22 The principal elements of the construction works and operational procedures that would cause landscape character impacts are then identified. (These are outlined in Part A ). 5.9.23 A brief overall assessment of the significance of landscape impacts is presented for each option. The significance of impacts is assumed to be a function of the magnitude of the impact and the sensitivity of the landscape character affected. Impacts are assessed during construction/operation; during afteruse without mitigation; and during afteruse with mitigation at Year 10. Impacts on Visual Receivers 5.9.24 The 'visual envelope' for each completed landfill is identified. The visual envelope is that area from which any part of the completed landfill can be seen. Identification of the visual envelope is achieved by site visit and desk-top study of topographic maps and photographs to determine visibility of the project from various locations. This is supported by computer analysis of the visual envelope. Visibility contours and sections are not presented. 5.9.25 All principal VSRs within the visual envelope are identified, at an aggregated level. The principal elements of the construction works and operational procedures that would cause visual impacts are identified. (These are outlined in Part B of the Report). 5.9.26 A brief overall assessment of the significance of landscape impacts is presented for each option. The significance of impacts is assumed to be a function of the magnitude of the impact and the sensitivity of the VSR. Impacts are assessed during construction/operation; during afteruse without mitigation; and during afteruse with mitigation at Year 10. 5.9.27 Visual impacts for each VSR group are tabulated and significant impacts are assessed as “Substantial”, “Moderate” or “Slight”. Impacts which are not significant are “Insubstantial”. 5.9.28 When assessing the effect of mitigation measures in reducing the significance of visual impacts, the following assumptions have been made:
• For island landfills, during the construction/operation phase, visual mitigation measures are more effective on VSRs at sea/ground level than on VSRs who view sites from an elevated level. This is because the former will have views screened by progressively vegetated bunds while the latter will see over these bunds into the landfilling areas;
• During the construction/operation phase, visual mitigation measures are more effective on distant VSRs than on those close to the sites. This is because in close views, intrusive details such as seawalls, leachate plants, haul roads, etc are still clearly visible (despite mitigation), whereas the effect of young planting is not as good. In more distant views, intrusive details are not visible in any case, whereas the overall effect of vegetation is more pronounced.
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• For island landfills, during the afteruse phase, visual mitigation is generally more effective on distant VSRs than on very close ones. This is because a new island in close proximity to a VSR will have the effect of dramatically changing the character of the view, meaning that mitigation measures such as ground shaping and vegetation cannot possibly remedy this. In more distant views, the effects of mitigation measures such as ground shaping and vegetation are more important in reducing those impacts which do arise. Illustrations and Graphic Material 5.9.29 The assessments for each potential landfill site are supported by illustrations, showing at a general or approximate level :
• Landscape resources (map, where applicable). • Landscape character (photograph). • Landscape planning designations (plan). • Visual envelope (plan). • Views of key visual receiver groups (photographs). • Outline mitigation measures (plan). • Photomontages will be prepared for each option, showing the completed landfill without mitigation and with mitigation at Year 10 of afteruse. The number of locations from which photomontages are prepared is between 1 and 3, as agreed with Planning Department for each site.
Generic Landscape/Visual Mitigation 5.9.30 This section sets out in broad terms, mitigation measures generic to all landfill sites. Mitigation is specified at a broad level only as it is assumed that it would be developed in more detail at full EIA stage. 5.9.31 Landscape and visual mitigation measures for the landfill sites will generally include:
• Good working practice to reduce impact on surrounding vegetation during construction/operation phase (where applicable). • Advance screen planting (where possible). • Mitigation of visual impacts of landfill temporary slope works. • Progressive restoration to minimise landscape/visual impacts over time. • Careful location and colour treatment of associated structures (haul roads, leachate plant, engineered slopes and run-off channels). • Variation in height profile of restored extension. • Variation in contouring of slopes. • Re-use as publicly accessible open space linked to nearby hiking trails. • Re-vegetation to simulate natural shorelines and naturally vegetated hillsides.
5.9.32 Re-vegetation to simulate natural shorelines and naturally vegetated hillsides. (Generally, landscape restoration should aim to achieve natural vegetation patterns and typical mix of ecologically appropriate species, where possible and consistent with other land use requirements to be determined later.) 5.9.33 Each site will be restored to pre-agreed contours, through landscaping and vegetation planting, as shown in the agreed Master Landscape Plan, by the landfill contractor. 5.9.34 To minimise the landscape and visual impact of landfilling operations, the site should be progressively restored, and a vegetation cover established as early as possible. This would also assist in reducing erosion of the capping layer and would minimise infiltration of rainwater.
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5.9.35 During the aftercare period, LFG and leachate would continue to be generated within the landfill (albeit leachate at a lower rate) and so the collection and management systems must continue to operate, resulting in a low level of landscape/visual impact. 5.10 Landfill Gas Issues Introduction 5.10.1 As described in Section 3.8, LFG issues are considered a primary environmental concern in the development of landfill sites. LFG is a flammable and asphyxiating mixture of methane and carbon dioxide, often with trace amounts of toxic volatile compounds. It is a product of the anaerobic decomposition of solid wastes. Explosion can occur when methane in concentrations between 5% and 15% by volume (representing the lower and upper explosive limits, LEL and UEL respectively) is mixed with air in confined spaces and given a source of ignition, such as an electrical spark. 5.10.2 LFG comprises mainly methane and carbon dioxide, both of which are greenhouse gasses. Methane is the more potent of the two gasses, by a factor of around 21. To reduce the greenhouse gas impacts from methane, it must be oxidised (into carbon dioxide) through combustion :
• Direct on-site use of LFG as an energy source, e.g., heating leachate during treatment. • Using a gas-engine/generator to convert LFG into electricity, e.g., to provide all site electricity requirements. • Flaring of surplus LFG.
5.10.3 LFG is capable of migrating from its source to the potential target along any permeable media, such as cracks and fissures in the surrounding rock and other preferential paths of least resistance, such as utility routes (trenches and ducts). 5.10.4 Carbon dioxide emissions from waste degradation are considered to be biogenic, rather than anthropogenic in nature. Aerobic degradation of waste (through oxidation, which produces carbon dioxide) is a natural phenomenon and therefore part of the natural process of carbon cycling. For the purposes of assessing greenhouse gas impacts, it has been assumed that all collected methane would be oxidised to carbon dioxide and therefore the process of landfilling would have a neutral impact on greenhouse gas emission. 5.10.5 However, if the combustion of methane produces electricity for off-site use, which would otherwise have had to be generated at a power station by burning fossil fuels, then there would be an overall benefit. This “saving” would be equivalent to the mass of carbon dioxide not produced by burning fossil fuels to generate the electricity provided by on-site generation.
Government Legislation and Standards 5.10.6 There is no primary legislation covering hazards to development caused by LFG. A ProPECC Note, “Landfill Gas Hazard Assessment for Developments adjacent to Landfills” (PN3/96) has been issued by EPD. This Note sets out the conditions under which a LFG hazard assessment should be carried out. EPD have also produced a “Landfill Gas Hazard Assessment Guidance Note”(EPD TR8/97) which issues further guidance on undertaking LFG hazard assessments. The guidelines recommend that in general, assessment of risks from LFG are required for proposed developments that lie within a 250m “Consultation Zone” around the landfill site. 5.10.7 Chapter 9, of the Hong Kong Planning Standards and Guidelines also includes guidance on siting of developments in the vicinity of landfills. The guidance states that safe distances depend on factors such as the existence of gas control systems, barriers, landfill site configuration and geological conditions. Sections 1.1(f) of Annex 7 and Section 3.3 of Annex 19 of the EIAO Technical Memorandum also refer.
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Landfill Gas Sensitive Receivers 5.10.8 LFG sensitive receivers or “Targets” include any enclosed areas where people congregate where landfill gas can accumulate. This includes elements of buildings as well as excavations, tunnels etc. The degree to which such targets are “at-risk” from the effects of landfill gas is a function of the nature and proximity of the waste body, the occurrence of potential routes for LFG migration as well as the specific nature of the target. 5.10.9 During construction of the landfill, the contractor and others working on the landfill would be exposed to LFG hazards. This issue should be addressed by enforcing the contractor (and others working on the landfill) to adhere to strict working protocols and health and safety regulations, as part of their contract. This issue is not considered further at this stage within the SEA.
Generic Landfill Gas Mitigation 5.10.10 The principal approach to mitigating landfill gas impacts is through mitigation at source through effective controls implemented in the landfill design, as described in Section 3.8. 5.10.11 In addition specific measures can be applied to protect Targets, through implementation of a variety of measures defined on a case by case basis according to the specific degree of risk as concluded through a landfill gas hazard assessment as part of an EIA. 5.10.12 Combustion of collected LFG oxidises methane to carbon dioxide, a less potent greenhouse gas, and can be achieved either through flaring the gas and/or utilising it in a gas-engine to generate electricity for on-site and/or off-site use. Raw LFG can also be piped off-site for use by a third party (e.g. as a substitute for “towngas” manufacture).
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Evaluation of Landfill Gas Impacts 5.10.13 The evaluation criteria for assessing Landfill gas impacts are shown in Table 5.14.
Table 5.14: Landfill Gas Impact Evaluation Criteria
Criteria Score Construction / Operation 1 Distance between the new / O >500m (precautionary 2 x Landfill gas extended landfill and SRs consultation limit) - 250-500m - - <250m (within landfill gas consultation zone) 2 Number of receivers within O None 250m (i.e. Consultation Zone) - Up to 10 - - Over 10 3 Man-made / natural pathways O None for LFG migration - Pathway near landfill but indirect to SR - - Pathway from landfill and direct to SR 4 Additional utilisation of LFG to + Potential nearby user of surplus LFG / electricity reduce GHG emissions O No potential users of LFG (other than on-site use) 5 Overall impact O Neutral - Negative – Low - - Negative – High
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PART B SITE SPECIFIC DETAILS
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6. DEEP BAY ISLAND LANDFILL 6.1 Basic Information Project Title 6.1.1 Deep Bay Island Landfill (DBIL) – marine site M.1. Nature of Project 6.1.2 The Project would form a new marine based waste disposal site in the middle of Deep Bay (Figure 6.1). 6.1.3 The Deep Bay waste disposal site would require the construction of an artificial island of approximately 670ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 6.1.4 The DBIL site is located approximately 0.8km to the north of the existing WENT Landfill and would cover a site area of some 670ha. Approximately 150Mcum of fill material would be required to construct the artificial island, with a final site formation level to +6 mPD. The capacity of the landfill site would be 110Mcum. 6.1.5 Seabed levels in this area vary from 2 to 5m below Chart Datum, with generally shallower waters towards the southern boundary of the site. The shallow water depths may pose some constraints on the selection and operation of marine vessels that would be required to supply materials and equipment to the site. It is understood that there would be no need for dredging works.
History of Site 6.1.6 The DBIL is located within open marine waters and would be entirely formed as part of this project. There has been no previous development activity specifically within the proposed site area. 6.1.7 There are proposed works for the Shenzhen Western Corridor (SWC) and Deep Bay Link (DBL) nearby. The gazetted works for SWC will be a bridge linking Shekou (in Shenzhen) and the Northwest New Territories in the HKSAR, and for DBL will be a trunk road linking the proposed SWC from its HKSAR landing point to the existing Yuen Long Highway. The landfall for the SWC on the Shenzhen side will be on an area of reclaimed land (in Dongjiaotou) over 2km north of the DBIL site, and the HKSAR landing point will be at Ngau Hom Shek in Yuen Long. 6.1.8 The proposed Waste-to-Energy Facility (WEF) at Ha Pak Nai is located some 1.8km south of the DBIL Site, although this has not yet been confirmed. As the WEF, SWC and DBL are designated under the EIA Ordinance, an EIA Study and other specialised studies are being undertaken for these projects.
Number and Types of Designated Projects covered 6.1.9 The DBIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1.
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6.2 Outline of Planning and Implementation Programme 6.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 6.2. Assuming landfill operations start in 2016, DBIL would be full during the period 2030 to 2040, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 6.2.2 The site is currently not covered by any statutory town plans. As described in Section 3.3, Town Planning Ordinance procedures to cover the proposed site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 6.2.3 The site is outside of the Study Area for the Planning and Development Study on North West New Territories. However, developing a landfill on this site is unlikely to be compatible with the planning intention of this area, especially as Deep Bay is recognised as an area of high ecological significance. 6.2.4 The Deep Bay, Mai Po Marshes and its adjacent area (collectively known as the Deep Bay Area) is recognised as a wetland of international importance. It is a habitat for a variety of species of waterbirds, and a stopover point for thousands of migratory birds. The Deep Bay Area comprises natural and man-made wetlands that provide a wide range of habitats to support a high diversity of biota. The Mai Po Marshes, the Inner Deep Bay and the surrounding fishponds have been listed as a “Wetland of International Importance” (the “Ramsar Site”) since 1995. Such designation recognises the ecological importance of the Deep Bay Area as a wetland habitat and landing and resting point for a number of migratory birds. 6.2.5 The northern shore line of this part of the North West New Territories to the south of this site is designated as a Coastal Protection Zone and is included under the Sheung Pak Nai & Ha Pak Nai OZP Plan No. S/YL-PN/4. 6.3 Possible Impacts on the Environment 6.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the DBIL are outlined below. Figure 6.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 6.1 and 6.2.
Air Quality 6.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation (following reclamation). • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
6.3.3 No Air Sensitive Receivers (ASRs) exist within a 500m radius from the boundary of this site. The closest ASR is Ha Pak Nai Village that is located some 1.8km south of the site boundary. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated.
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6.3.4 The SWC running adjacent to the site will be completed in the year 2005/2006. There will likely be vehicular emissions (RSP and NO2) arising from future vehicle traffic that may contribute to the operational phase emissions. The WEF at Ha Pak Nai and the Black Point Power Station located over 3km to the southwest of the site will also give rise to gaseous emissions (NO2 and SO2). However, as there are no identified ASRs, no cumulative impacts are anticipated. 6.3.5 The DBIL is a marine site and the mode of transportation will likely be by marine vessels. As such, the site will likely be served by those refuse transfer stations with marine / transfer facilities. According to the information provided in the Preliminary Marine Review Report (March 2002), the estimated cumulative distance travelled for waste delivery is approximately 380km, assuming the proposed site will receive waste delivered from the existing network of marine transfer stations (including Island East, Island West, West Kowloon, North Lantau, South East Kowloon and Outlying Islands Transfer Stations). Given the likely distance to be travelled and the benefit of the use of marine transport, the regional impacts from waste transportation are considered to be neutral to minor. 6.3.6 The site lies in an open marine area with the prevailing wind direction from the northeast. The site location is not within an airshed and there would not be any accumulation of air pollutants.
Noise 6.3.7 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
6.3.8 No existing or planned noise sensitive receivers (NSRs) have been identified within 300m of the site. 6.3.9 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue. 6.3.10 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 6.3.11 The SWC running adjacent to the site will be completed in the year 2005/2006. There will be road traffic noise arising from the future road link that may be cumulative to the operational noise. However, as there are no NSRs identified, no cumulative impacts are anticipated. 6.3.12 The DBIL can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
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Water Quality Baseline Conditions at the Site 6.3.13 Deep Bay is a large shallow bay on the east bank of the Pearl Estuary, adjacent to the relatively deep flood channel of Urmston Road. The Bay has a surface area of approximately 112km2 (11,200ha), with a length of about 15km and an average depth of 3m. The total catchment area of the Bay is about 535km2, with 51% of the catchment in Shenzhen and Shekou and the remaining 49% in Hong Kong.1 6.3.14 Due to its conservation significance and increasing pressures from development within its catchment, in 1990 Deep Bay was designated by the Hong Kong - Guangdong Environmental Protection Liaison Group as the highest priority study area requiring protective conservation action. As a result a study to evaluate the Bay’s dispersive and assimilative capacity and develop strategic management options to improve the water quality in the Bay was commissioned in 1995 and completed in 1998. 6.3.15 The Deep Bay Water Quality Control Zone can be divided into the inner and outer sub-zones, across which the site extends. Based on data from EPD’s routine marine water monitoring programme for the year 2000, the water quality in the inner sub-zone is generally of poorer quality that that in the outer sub-zone; particularly for suspended solids and inorganic nutrients. It is noted however that background levels of suspended solids in Deep Bay are high due to the nature of the Pearl River discharge. 6.3.16 The hydrodynamic regime of the Deep Bay area is unidirectional and the current direction reverses during ebb and flood tides. During an ebb tide, currents gradually form at the river mouth in the Deep Bay catchment, then flow from the inner subzone towards the outer subzone with an increasing magnitude, and finally join the southward currents originating from the Pearl River Estuary. During a flood tide, the flow direction reverses with currents flowing from the outer subzone towards the inner subzone. The currents originate from the eastern and southern waters of Hong Kong and are generally stronger in magnitude than the currents during an ebb tide. As the ebb flows leaving Deep Bay are much weaker than the incoming flood flows, pollutants from inner Deep Bay are not well dispersed following discharge at the river mouth. 6.3.17 Past studies have previously identified the breakdown of the overall pollution loading to Deep Bay and particularly the significance of the contribution of the rivers discharging into Inner Deep Bay (i.e. the inner sub-zone). The EPD data for year 2000 shows levels of total inorganic nitrogen (TIN) above the WQO at all monitoring stations, with non-compliance for un-ionised ammonia throughout the inner sub-zone. 6.3.18 Marine sediment quality tests were performed at the central section of Deep Bay under the Shenzhen Western Corridor site investigation works contract. The results of the test indicate the sediment samples tested consisted of Category L, Category M and Category H sediment. The sediment was deemed suitable for either open sea disposal or disposed at a Confined Marine Disposal Ground. Elutriate tests were also conducted to estimate the potential for contaminant release in the marine waters during dredging for the SWC works and revealed that there was high potential for release of copper, zinc, arsenic and tributly-tin (TBT) from the sediment.2
1 Hyder Consulting Ltd & CES Ltd (1998). Deep Bay Regional Water Quality Control Strategy Study: Final Report. For EPD, Government of the HKSAR. 2 Arup (2002). Shenzhen Western Corridor: Draft Final Report on Water Quality Mathematical Modelling Study and Water Quality Impact Assessment. February 2002.
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Key Issues and Sensitive Receivers 6.3.19 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
6.3.20 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the site. These include:
• Secondary contact recreation subzone at the shoreline from Black Point to Tai Shui Hang and the Yung Lung non-gazetted beach to the southeast; and • Cooling water intake for CLP’s Black Point Power Station.
6.3.21 In addition, there are a range of aquatic and inter-tidal ecological receivers within the site that would be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed within the ecology and fisheries subsections. The sensitive receivers include:
• The Inner Deep Bay Site of Special Scientific Interest (SSSI) to the east; • Fu Tian mudflat and mangrove Nature Reserve in Shenzhen to the east; • Mai Po Marshes SSSI to the southeast; • Tsim Bei Tsui SSSI to the southeast; • Pak Nai SSSI and nearby seagrass areas to the south; • Horseshoe Crab habitat (sub-tidal and inter-tidal) near Ha Pak Nai • Mudflat and mangroves near Ngau Hom Shek; • Mariculture subzone at the southern boundary of the site (i.e. oyster/shellfish beds at Lau Fa Shan and generally along the southwest Deep Bay coastline); and • Oyster beds at Shekou (Mainland waters).
6.3.22 The Study Area coincides with the northern boundary of the Chinese White Dolphin habitat. Dolphin sightings have been recorded in inner and outer Deep Bay during summer and autumn months by the AFCD. The waters of the Lung Kwu Chau and Sha Chau Marine Park to the southwest where dolphin activity is concentrated are also potentially sensitive. The locations and uses of the WSRs are shown in Figure 6.1. Reclamation and Site Formation 6.3.23 During reclamation and site formation phase of the artificial island, sediment handling may lead to water quality impacts from increased suspended solids and reduced dissolved oxygen. There is also potential for sediment plumes to form and be dispersed by the prevailing water current. The extent of the sediment plume dispersal will depend on the size and character of the fill material(s) (i.e. dredged sand or muds) and hydrodynamic conditions. 6.3.24 The hydrodynamic and water quality modelling predicted significant exceedances above the WQO (30%) during both the wet and dry season for all three construction phases at SI1 (54.68% increase to 191.65% increase) and SG1 (35.15% increase to 126.96% increase) to the west of Sheung Pak Nai in Deep Bay. Elevated SS levels (up to 14.98%) were predicted at OB2, MG, S12, OB1 and CW1 in Deep Bay for both the wet and dry season for all three construction phases and at MA in Inner Deep Bay for the dry season for all three construction phases.
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Hydrodynamic and Water Quality Impacts Following Island Formation 6.3.25 The presence of the island will not cause any noticeable changes to momentary or accumulated flow for the East Lamma or West Lamma Channels; however, the accumulated flow across the Tathong Channel is predicted to increase by 14.43% during the wet season and 0.05% during the dry season. The presence of the proposed island would cause a significant increase in current (38.22% on average) in the channel formed to the east, between the artificial island and the New Territories. 6.3.26 As the island would be located between the inner and outer Deep Bay cross sections, it was predicted that the site would reduce the fluxes through both inner and outer Deep Bay Channels with a considerably higher relative reduction (ranged from -5.37% to -7.02%) at outer Deep Bay as compared to inner Deep Bay (ranged from +0.06% to -2.08%). It is believed that the proposed island would reduce the flushing capacity of Deep Bay. The pollutant levels within Deep Bay would potentially increase as more pollutant (discharged from the Deep Bay catchments) would tend to accumulate inside the bay due to the reduction in the flushing capacity. This can be further supported by the changes in salinity levels at the stations within inner Deep Bay. The model predicted that the salinity levels would decrease in inner Deep Bay due to the proposed island suggesting that more freshwater (and thus more pollutants) discharged from the rivers flowing into inner Deep Bay would be accumulated inside the bay. 6.3.27 The water quality modelling, under the baseline scenario, identified that a significant amount of nutrients from the Pearl River would be washed into Deep Bay. The presence of the island would reduce the tidal flows into Deep Bay and thus block part of the nutrients from entering Deep Bay, however, the island is not a preferred site in terms of water quality impact due to the fact that the proposed island would potentially reduce the self-cleansing capacity of Deep Bay, and there are uncertainties about the future pollution loading discharged into Deep Bay, especially as a portion of the pollutants loadings is from Shenzhen, which is not under the control of HKSAR Government, 6.3.28 In the Hydrodynamic and Water Quality Modelling, 7 sensitive receivers that are close to the site were selected for presentation. Of the 7 chosen indicator points, 4 are located in the inner Deep Bay WCZ (MA, SI2, OB1 and SI1), 2 are located in the outer subzone of Deep Bay (SG1 and CW1) and the remaining 1 is located in Mainland waters (OB2). 6.3.29 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 7.01 to 7.85mg/L and 6.70 to 7.76mg/L respectively which complied with the WQO of ≥4mg/L for depth averaged DO and ≥2 for bottom layer DO. The predicted DO levels at OB2 (ranged from 7.47 to 8.77mg/L) also complied with the Mainland standard of >5mg/L. 6.3.30 The predicted average dry season salinity ranged from 27.27 to 28.29ppt. The differences in salinity levels caused by the presence of the island were minimal (less than 1%) at all the selected indicator points and the differences are well below the WQO of 10%. 6.3.31 The predicted dry season SS levels at the indicator points were in the range of 10.66 to 16.97mg/L. The percentage differences caused by the presence of the island were within 3%. Recognising that the WQO requires that any waste discharge should not raise the natural ambient level by more than 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, the differences in SS at all indicator points are considered to be small.
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6.3.32 The average E.coli levels in the dry season ranged from 20 to 5851count/100ml. Comparing to the WQO of 610cfu/100ml, exceedances were found at MA and SI2 (5851count/100ml and 5781count/100ml respectively). However, the differences caused by the island were minimal (less than 1%) at these 2 stations. The average E.coli level at OB2 is 2 which complied with the Mainland standards of 14count/100ml for shellfish culture zone. The predicted E.coli levels at all other stations were low and well within the WQO of 610count/100ml. 6.3.33 The predicted average dry season UIA (0.00233 – 0.00848mg/L) were very small as compared to the WQO of 0.021mg/L as well as the Mainland standard of 0.02mg/L. 6.3.34 The dry season TIN levels ranged from 0.166 to 0.342mg/L. For OB2 in Mainland waters, the predicted dry season TIN level with the presence of the island is 0.166mg/L which complied with the Mainland standard of 0.3mg/L. Since the Hong Kong WQO of TIN is an annual mean value, the predicted mean TIN levels for the dry and wet seasons were averaged to represent the annual mean values. The calculated concentrations (ranged from 0.350 to 0.466mg/L) showed to be below the WQO for TIN of 0.5mg/L and 0.7mg/L for Deep Bay WCZ (outer subzone) and Deep Bay WCZ (inner subzone) respectively. 6.3.35 According to the wet season water quality modelling results, for the indicator points in Deep Bay WCZ, the predicted 90%ile DO for depth averaged and bottom layers ranged from 5.05 to 8.54mg/L and the values are above the WQO of 4mg/L and 2mg/L respectively. The predicted DO levels at OB2 (ranged from 6.49 to 7.95mg/L) also complied with the Mainland standard of 5mg/L. 6.3.36 The predicted average wet season salinity at the indicator points ranged from 1.91 to 5.05ppt. It is predicted that the presence of the island would reduce the salinity at all of the indicator points in Deep Bay with the largest reduction at SG1 of 3.75%. The predicted differences are considered small as compared to the WQO that requires change due to any waste discharge should not raise the natural ambient level by more than 10%. 6.3.37 The predicted wet season SS levels at the indicator points in Deep Bay WCZ were in the range of 15.06 to 38.97mg/L. It is predicted that the island would increase the SS levels at most of the indicator points in Deep Bay WCZ. Recognising the WQO requirement that any waste discharge should not raise the natural ambient level by 30%, the predicted differences are however small (within 5%). OB2 showed an increase in the SS level by 7.67% but the predicted increase complied with the Mainland standard that man-made increment shall not exceed 100mg/L. 6.3.38 The predicted wet season E.coli levels at the indicator points in Deep Bay ranged from 1 to 2879count/100mL. Exceedances were found at MA and SI2 (2100count/100ml and 2879count/100ml respectively). However, the differences caused by the island were minimal (less than 2%) at these 2 stations. The average E.coli level at OB2 was 1 which complied with the Mainland standards of 14count/100ml for shellfish culture zone. The predicted E.coli levels at all other stations were low and well within the WQO of 610count/L. 6.3.39 The predicted average wet season UIA (0.00581 – 0.00635mg/L) at the indicator points in Deep Bay were low and well below the WQOs of 0.021mg/L. Compared to the baseline water quality results, the percentage differences caused by the presence of the island were small (less than 0.2%). 6.3.40 For predicted wet season TIN levels at the indicator points in Deep Bay WCZ, the values were quite high and ranged from 0.206 – 0.679mg/L. Since the Hong Kong WQO of TIN is an annual mean value, the predicted mean TIN levels for the dry and wet seasons were averaged to represent the annual mean values which were discussed in Section 6.3.34. OB2 was identified to have an increase in the TIN level of 4.25%. The wet season mean TIN levels at OB2 for both the baseline and operational scenarios (0.400 and 0.417mg/L respectively) exceeded the Mainland standard of 0.3mg/L.
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Cumulative Impacts 6.3.41 Outer Deep Bay, which overlaps with the site, is currently gazetted for sand dredging with constraints. From a logistical point of view, the construction of the artificial island is based on the premise that all potential dredging or marine borrowing at the same location will have been completed prior to construction. Thus, it is not anticipated that any borrowing activities will occur concurrently with the construction of the artificial island. As such, no cumulative impact in this regard is expected. 6.3.42 The bridge alignment has been gazetted for the SWC project. As such, there will be dredging works required for the bridge piles and coastal reclamation works at the Shekou Peninsula. However, such works would be complete before the start of works for the proposed artificial island site – scheduled for circa. 2011. There is, however, potential for cumulative hydrodynamic effects from the SWC reclamation and the hydrodynamic change induced by any artificial island in Deep Bay. The extent and magnitude of cumulative impacts would need to be considered further under a detailed EIA study.
Waste Management / Disposal Impacts 6.3.43 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessels, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 6.3.44 Various options for construction have been explored for this site and it is anticipated that muds would not need to be excavated to facilitate construction of the outer seawall, prior to public filling. Upon completion of construction, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 6.3.45 Anticipated volume of materials are as follows:
• Volume of public fill that could be accepted for island construction: 150Mcum.
6.3.46 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples include chemicals for wastewater / leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 6.3.47 Waste delivery, to DBIL will be by marine vessel, which will have a lower GHG emission rate (in term of per kg waste handled) compared to delivery by road transport, given the amount of waste that can be carried by a marine vessel is 100 times more than a truck. The cumulative distance between marine RTSs and the site is around 380km (as stated in the Preliminary Marine Review (March 2002)) and therefore the potential GHG emissions from waste delivery to this site is considered to be neutral to minor.
Ecology Baseline Conditions 6.3.48 The ecological value of the broader Deep Bay area has been documented by a number of academic and Government-commissioned studies. The Inner Deep Bay area in particular is the most studied ecosystem (in fact, series of ecosystems) in the HKSAR by virtue of its habitat diversity and relative isolation. Much of the land and coastal area in Inner Deep Bay is protected within the Mai Po Marshes Nature Reserve (MPMNR) that was designated a ‘Restricted Area’ and SSSI in the mid-1970s. As defined under the Wild Animals Protection Ordinance (Cap. 170, Schedule 6), the Restricted Area includes “Mai Po Marshes, all the mangrove swamps adjoining the Marshes, and the intertidal mud flats and shallow waters of Inner Deep Bay”.
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6.3.49 The estuarine waters of Inner Deep Bay were designated as a SSSI in 1986, and in recognition of the area’s diverse range of wetland habitats and its special conservation value for migratory birds, the Mai Po & Inner Deep Bay Ramsar Site was established in September 1995. 6.3.50 Due to its cross-boundary situation, there have also been a number of ecological studies of Inner Deep Bay solely or jointly undertaken by Mainland authorities and organisations. In contrast, there has been relatively little study into the habitat and community types outside Inner Deep Bay due to relative habitat homogeneity and the lack of inter-tidal expanses that otherwise provide habitat for a range of communities (e.g. mangrove, mudflat and brackish marsh). 6.3.51 The hydrodynamics in Deep Bay influences a range of sub-tidal and inter-tidal ecologically sensitive receivers in Inner Deep Bay (subsection 6.3.21 and Figure 6.1 refer). The ecological significance of these receivers is summarised in Table 6.1 below.
Table 6.1: Significance of ecologically sensitive receivers in the Study Area
Name of Receiver Significance Inner Deep Bay SSSI The largest and most important mangrove habitat in the HKSAR, and the mudflats – that are of high conservation value in their own right due to endemic infauna species - are also a vital feeding ground for tens of thousands of resident and migratory birds. Fu Tian Nature Reserve Only remaining area of mudflat and mangrove habitat in Shenzhen. Mai Po Marshes SSSI Largest area of dwarf mangrove habitat in the HKSAR and has high scientific and educational value due to the number of waterbirds it supports in its ponds. Tsim Bei Tsui SSSI A mature mangrove community including a good assemblage of uncommon mangrove species. Pak Nai SSSI Important roosting site for gulls and herons. Locally and regionally rare seagrass / Horseshoe Crabs nearby. Ha Pak Nai / Ngau Hom Shek Seagrass and Horseshoe Crab nursery / breeding habitat. coastline Chinese White Dolphins High profile protected species that inhabits the Pearl River Estuary waters. Sources: Consultants / Aspinwall Clouston & Wetland Intl (1997) 3.
6.3.52 There is a range of species of high conservation importance in the Inner Deep Bay area, as well as beyond the Inner Bay closer to the site. Species of particular note in Inner Deep Bay wetland bird community are the Dalmatian Pelican, Chinese Egret, Oriental Stork and Saunders’ Gull that are listed on Appendix I of the Bonn Convention. Globally threatened bird species include Nordmann’s Greenshank and the Spoon-billed Sandpiper. 6.3.53 Other species of conservation importance in the area include the seagrass, Haolphila baccarii, and two of Southeast Asia’s three species of Horseshoe Crab (Tachypleus tridentatus and Carcinoscorpius rotundicauda) have been identified near Ha Pak Nai. Mammals, including the Chinese otter and Crab-eating mongoose that have been observed at Mai Po and Tsim Bei Tsui, may include other areas along the Ha Pak Nai coastline within their ranges. 6.3.54 Accordingly, any deterioration in water quality or change in hydrodynamics brought about by the proposed disposal facility may potentially adversely affect these ecological resources.
3 Aspinwall Clouston & Wetland Intl (1997). Development of a Comprehensive Conservation Strategy and Management Plan for the Mai Po & Inner Deep Bay Ramsar Site: Final TP4.
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Direct Habitat Loss 6.3.55 The site footprint covers a surface area of 670ha. The existing site area is entirely sub-tidal, thus generally providing no feeding opportunities for water birds or other terrestrial species, and is comprised of soft muds. Specific details on the benthic assemblages at the site are not known, although it is known that two species of Horseshoe Crab inhabit the general area (with sightings along the Ha Pak Nai coast). As Horseshoe Crabs feed mainly on molluscs and polychaetes it is likely that these prey taxa are well represented in the sub-tidal waters, just as they are in the inter-tidal waters of Inner Deep Bay. There is also likely to be a variety of crustaceans in the area. Adult Horseshoe Crabs will also form an important component of the sub-tidal marine environment of the site; and site formation activities could potentially lead to adverse impacts on what may be important spawning and nursery grounds for these species. 6.3.56 During construction works for the DBIL there is potential for sediment plume formation and dispersal, affecting sensitive ecological receivers. The final results of the water quality and hydrodynamic modelling exercise reveal that suspended solids levels at Pak Nai SSSI and at the seagrass / Horseshoe Crab habitat at Ha Pak Nai would be greatly increased during all island formation phases, with suspended solids levels at Pak Nai SSSI reaching 40mg/L (183% above baseline levels at Pak Nai SSSI (SI1)). The dry season concentrations at the seagrass habitat that is particularly sensitive to sedimentation effects are predicted to be in the order of 127%. Water Quality / Hydrodynamics 6.3.57 Locating DBIL across the middle of Deep Bay would further restrict the flow of water in an area of already limited dispersive capacity. The decreased flushing capacity may decrease the assimilative capacity of the Inner Bay, meaning that inorganic and organic pollutants in riverine discharges would be retained longer in Inner Bay and would thus be more readily available for biological uptake. The resulting decline in water quality could have significant effects for the benthic community on the inter-tidal mudflats of Inner Deep Bay. The mudflat area is the principal feeding ground for tens of thousands of migratory birds (including several globally endangered and internationally protected species) that rely on feeding opportunities provided by the diverse and abundant benthic community. 6.3.58 The island may induce change in sediment deposition and erosion patterns, with potentially significant adverse impacts on some areas of mudflat in Inner Deep Bay where sedimentation provides an opportunity for mangrove and grass encroachment, thus reducing the area of valuable mudflat habitat as a feeding ground by birds (i.e. potentially reducing the carrying capacity of the mudflat). Any increase in suspended solids or sedimentation would have an adverse effect on the seagrass habitat located due south of the site. There may also be increased scouring of inter-tidal habitats with the result that areas of mudflat and mangrove habitat are eroded and undermined. This would also further increase suspended sediment levels in the water column with effects on water quality. 6.3.59 Despite these potential hydrodynamic effects, the model output does not indicate that site would lead to any significant change in water quality from baseline conditions. The most significant result is a predicted increase in E.coli levels at Pak Nai SSSI of 15 counts / 100ml (22% above baseline). Whilst this increase is not significant in terms of WQOs, there could conceivably be some effect on the ecological function of the coastal habitat, such as a change in benthic community composition affecting bird feeding opportunities.
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6.3.60 There is high potential for cumulative ecological impacts induced by hydrodynamic and water quality changes during the operation stage of the site, from the committed SWC that will involve coastal reclamation works at Shekou, Shenzhen and at Ngau Hom Shek, Hong Kong if the bridge option is selected. The extent and magnitude of cumulative impacts would be considered further at the detailed EIA stage of the project, when further information regarding the implementation programme is known. Marine Vessel Disturbance 6.3.61 Sightings of the Chinese White Dolphin Sousa chinensis have been made in the area between June and August, with observations all year round at the mouth of Deep Bay and along Urmston Road. Marine transportation of fill and construction material, and operational marine traffic all give rise for potential collision and noise disturbance with these mammals. This may be a particular concern given the shallow water depth and hence the limited water column available for impact avoidance.
Fisheries Marine Fisheries 6.3.62 The Study Area is not a key fishing area due to shallow water depths that constrain vessel navigation and the abundance of cargo vessels (mainly marine vesselss) that ply these waters between the Shenzhen River and the Pearl River. 6.3.63 A consultancy study investigating fishing resources and operations in the HKSAR was commissioned by the AFCD in the mid-1990s. A series of sampling techniques were used to determine fisheries yield. It was originally envisaged (prior to field survey) that a gillnetting exercise off Ha Pak Nai would produce a low fish yield, however a high yield was recorded. Purse seining was conducted at the location of the proposed artificial island where the fisheries yield was considered “low”.4 Oyster Fisheries 6.3.64 According to AFCD sources, oyster culture has been practised along the inter-tidal mudflat of Deep Bay for some 200 years. The current culturing practice involves fattening of young oysters imported from the Mainland typically for between six to twelve months before marketing. For operation convenience and faster growth, fattening is carried out mostly by raft culture. Oyster production in 2000 was some 76 tonnes with a value of $3 million.5 6.3.65 It is understood from AFCD that there are oyster raft culture activities within the site boundary of the DBIL. Whilst there are no specific details of these activities, the DBIL would lead at best to displacement of these activities to other inshore waters, and at worst to a cessation of the operation altogether. The potential for water quality impacts associated with the DBIL works would possibly make recommencement of the oyster farming in nearby waters unfeasible. 6.3.66 There are also oyster-farming activities in Mainland waters near Shekou. The water quality for oyster farming zones in Hong Kong and Mainland waters of Deep Bay has been predicted using the numerical water quality / hydrodynamic model. The output for the Hong Kong oyster zone (OB1) shows a peak increase in suspended solids levels during the island formation works of around 2mg/L to (a 15% increase above baseline). The increase at Shekou (OB2) is negligible (< 1mg/L). These increases would not be expected to be significant as they fall within the baseline range. The model does not predict any significant change in hydrodynamics / water quality as a result of the development of this site.
4 Environmental Resources Management (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to the Agriculture and Fisheries Department, Hong Kong Government. 5 AFCD (2001). “Aquaculture Fisheries” [AFCD Website: www.afcd.gov.hk/web/english/fisheries/fish/aquac.htm].
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6.3.67 In the short-term, the planned SWC project will involve engineering works in the vicinity of the oyster production area along the Deep Bay coastline. It is understood that as the SWC will require inter-tidal and sub-tidal construction works, compensation is to be provided to oyster farm operators for loss of income. As the SWC Study is ongoing, precise details of impacts and the future of oyster production in this area are unavailable. However, given the economic climate of oyster farming in the Deep Bay area, the DBIL and / or the planned SWC would lead to adverse impacts upon this industry.
Cultural Heritage 6.3.68 There is no immediate evidence of archaeological remains in this area. However a number of land based archaeological sites lie along the coastline of Deep Bay and provide evidence that the coastal area of Tuen Mun and Yuen Long was occupied by early human settlement, and also frequently used by seafaring people for several thousand years. 6.3.69 From west to east, these archaeological sites include:
• Tsang Tsui Archaeological Site (to the west of the WENT Landfill); • Ha Pak Nai Archaeological Site (to the east of the WENT Landfill); • Tsuen Ng Ka Yuen Archaeological Site; • Long Jok Tsuen Archaeological Site; • Pak Nai Archaeological Site; • Fu Tei Au & Ngau Hom Shen Archaeological Site; • Sha Kong Archaeological Site; • Tseung Kong Wai So Kwun Tsai Archaeological Site; • Hang Hau Tsuen Archaeological Site; • Tung Tau Tsuen Archaeological Site; and • Lau Fau Shan Archaeological Site.
6.3.70 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 6.3.71 Landscape Planning Designations - while this area of landscape is not covered by any planning designations reflecting landscape values, the close proximity of the site to the existing coast line will conflict with the intention of the adjacent Coastal Protection Area identified in the Outline Zoning Plans for Sheung Pak Nai and Ha Tsuen. The relationship between coast and sea will be fundamentally changed although the coast itself will not actually be affected and resulting impacts will be slight. 6.3.72 Landscape Resources - as the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 6.3.73 Landscape Character - the site falls within the Deep Bay LCA (Figures 6.3 and 6.4). This is a shallow and contained coastal bay between the western New Territories and Shenzhen. The bay is low-lying and exposed and contains numerous mud flats that are exposed at low tide. The bay generally has a remote and undisturbed character save for the proximity of high-rise building in Shenzhen. The Castle Peak uplands form a dramatic natural coastline on the southern side of the bay, although the coast is somewhat degraded by power station development.
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6.3.74 There exists potential for high impacts on landscape character resulting from construction/operation works, which will introduce new artificial elements that are incompatible with the existing open and natural characteristics of the bay and coastal landscape. Upon restoration of the landfill, these impacts are likely to be reduced somewhat. The somewhat artificial character of the island, however, will contrast with the generally natural characteristics of the existing coastline. As a consequence of this, impact on landscape character will be substantial to moderate during the construction/operation phase, whilst during the afteruse phase; the residual impact will reduce to moderate. 6.3.75 VSRs - VSRs affected by the proposals are identified in Tables 6.4 and 6.5. The extent of the project visual envelope is shown in Figure 6.5. 6.3.76 Located on the eastern edge of Deep Bay, the site is largely screened from high-density residential areas in Hong Kong by the Castle Peak Range. However, VSRs in taller buildings in Tin Shui Wai and Shenzhen will have distant views of the site. Key residential VSRs in the area are found at the villages of Ha Pak Nai, Sheung Pak Nai, Ngau Hom Sha, Lau Fau Shan and Sha Tu Tsuen as well as the two larger settlements mentioned above (Figure 6.6). The distance of these settlements from the source varies from 800m to 5km. Occupational VSRs include those working at the WENT Landfill and Black Point Power Station. Other VSRs include vessels using Deep Bay, road traffic along Nim Wan Road as well recreational users along Castle Peak Trail. Future potential VSRs of the island fill are the travellers on the proposed Shenzhen Western Corridor (SWC). If the SWC is completed, it will become an important “gateway” into Hong Kong and the location of the island landfill will have a substantial detrimental impact on these future VSRs. 6.3.77 The VSRs will experience works on the landfill (shipping, marine vessels, construction of the bridge and partially constructed island) as relatively close artificial elements contrasting with the natural qualities of the existing landscape. The coastal villages will be most noticeably affected by the construction / operation of the landfill, resulting in the loss of open and expansive views across Deep Bay, and for these villages the impact will continue through the afteruse phase. However the magnitude of this is offset to a small degree by the area's sparse population levels. The aggregate visual impacts will therefore be substantial during the construction/operation phase. After the restoration of the landfill, the aggregate visual impact of the island will be reduced from substantial to moderate. 6.3.78 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 6.8.
Landfill Gas 6.3.79 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 6.3.80 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
6.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 6.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to the Deep Bay artificial island site.
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Air Quality 6.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 6.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 6.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the reclamation of the island. Construction procedures, defining the rates and method of dredging and filling taking into account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments, although the effectiveness of silt curtains in mitigating high suspended solids impacts would need to be addressed.
Waste Management 6.4.5 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Ecology 6.4.6 At Ha Pak Nai and Ngau Hom Shek there are Seagrass colonies that require a relatively clear water column for photosynthetic activity. Whilst important in its own right, this habitat is of broader conservation significance for the shelter it provides the populations of Horseshoe Crab that occupy the shallow sub-tidal and inter-tidal environment. These habitats and species are all vulnerable to adverse impacts from sediment mobilisation and potential transportation over the broader area during reclamation works. The application of silt curtains around this Seagrass habitat should be investigated.
Fisheries 6.4.7 As with aquatic ecology, the transport of suspended sediment to the oyster aquaculture area and an overall decline in water quality from reduced flushing capacity in the area is a key concern. Any decline in the ability of these waters to disperse and assimilate water quality parameters such as heavy metals and faecal coliforms will increase the potential for absorption by shellfish and benthic invertebrates that form the basis of the food-chain. Whilst certain localised measures can be taken to control sediment levels, there would be no direct mitigation against a general decline in water quality.
Cultural Heritage 6.4.8 No specific measures are recommended at this stage for the protection of cultural heritage resources.
Landscape and Visual 6.4.9 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 6.8.
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6.5 Summary 6.5.1 A summary of the SEA for the DBIL is provided in Tables 6.1 and 6.2:
Table 6.2: Summary of Deep Bay Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment 1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within land use 500m of the proposed artificial island site. 2 Presence of topographic features O The site does not lie within any airshed and generally which could decrease or exacerbate experiences wind. It is unlikely that dust or odours impacts would accumulate around the site. 3 Occurrence of meteorological O Wind blows both towards and away from ASRs. No conditions which could exacerbate prevailing wind direction has been identified. impacts 4 Cumulative Impacts of relevant - The proposed Shenzhen Western Corridor may be emissions (TSP (construction), NOx, operational in year 2005/2006. There will likely be CO, SO2 – LFG Flare) taking into vehicular emissions (RSP and NO2) arising from the account ambient conditions future road traffic. 5 Total emission of air pollutants from O / - Access to the site would likely be by marine vessel territory-wide waste transportation only, with the cumulative distance to be travelled from RTSs to the landfill site estimated to be 380km. 6 Overall Air Quality Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment 1 Distance to areas of noise sensitive O There are no noise sensitive receivers (NSRs) within land use 300m of the site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (only applicable if there are NSRs Therefore, this criterion is not applicable. within 300m) 3 Cumulative Impacts of - The proposed Shenzhen Western Corridor running developments within 300m adjacent to the site will be completed in the year 2005/2006. There will be road traffic noise arising from the future road link that may be cumulative to the operational noise. 4 Overall Noise Impact O ‘Neutral’ – due to no NSRs are found within the assessment area.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial island. Not relevant. 2 Potential for sediment contaminant - Sediment testing undertaken in Inner Deep Bay and release close to the site has identified the presence of contaminated material. Disturbance of bottom sediment during reclamation may disturb and mobilise contaminants. 3 Potential impacts on WSRs - - WQO exceedance for SS is predicted to be (including increase or exceedance exceeded during the construction of the island. of WQO) It is predicted that the E. Coli and TIN in the operational phase will exceed their respective standards. Nevertheless, these were also exceeded in the baseline scenario. However the reduced flushing capability of Deep Bay due to the presence of the island in the operational phase may make the dispersion of pollutants from Deep Bay less efficient. Therefore, the presence of the island would cause significant impact to the water quality. 4 Potential Impacts on Groundwater O Artificial island. Not relevant. 5 Potential Cumulative Impacts - The proposed Shenzhen Western Corridor may induce cumulative impacts on the hydrodynamic regime and sedimentation. Discharges to Inner Deep Bay from the Pearl River and Shenzhen River may also compound changes in water quality and hydrodynamics brought about by the project. 6 Overall Impact - - Due to the significant exceedance of the SS WQO during the construction of the artificial island to the west of Sheung Pak Nai in Deep Bay and, nevertheless, the self-cleansing capability of Deep Bay would be suffered and, consequently more vulnerable to suffer impaired water quality; in particularly the pollution from Deep Bay catchment is uncertain. Therefore, the overall water quality impact is assessed as ‘Negative – High’.
Waste Management Assessment 1 Balance of Materials (surplus/deficit + The site could accommodate significant amounts of of public fill needed for landfill public fill (150Mcum), thus negating the need to development) import filling material for site formation. This site will not require the dredging of any muds. 2 GHG emissions from mode of O / - Waste will be delivered to the site via marine vessel. transport for delivery of waste to the The distance travelled from marine RTSs to the site site from RTSs to the site has been estimated to be 380km. 3 Overall Waste Impact O ‘Neutral’
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary - - The Works would affect the Pak Nai SSSI through environmental impacts on “Areas of water quality decline and sediment deposition / Absolute Exclusion” erosion. 2 Affects an important habitat - - Seagrass / Horseshoe Crab habitat at Ha Pak Nai would be affected. 3 Affects a species of conservation - - The Horseshoe Crab population and Seagrass on importance the south Deep Bay coastline are of high conservation value. . 4 Potential for Cumulative Ecological - Hydrodynamic changes from the SWC may affect impacts on sites of recognised value water quality and sediment dynamics in the area, including Inner Deep Bay. Riverine discharges to Inner Deep Bay may also lead to cumulative water quality / hydrodynamic impacts with direct primary and secondary ecological impacts. 5 Overall Ecological Impact - - The overall impact potential is rated as ‘Negative – High’ due to the sensitivity of the shallow Deep Bay ecosystem to change in hydrodynamics and water quality. The cumulative hydrodynamic / water quality effect of the SWC reclamation would exacerbate the potential for adverse ecological impacts in the Bay.
Fisheries Assessment 1 Potential for secondary - - The oyster mariculture zone at Lau Fau Shan and environmental impacts on “Areas of along the northwest NT coast is an “Area of Absolute Absolute Exclusion” Exclusion” but may be affected by the Works from an increase in suspended solids. 2 Affects an important mariculture / - - As above, DBIL would be located approximately 1km fisheries resources (including from the oyster (mariculture) zone and but water spawning / nursery ground) quality impacts may be of local significance. 3 Potential for Cumulative Fisheries - There is potential for a cumulative hydrodynamic Impacts on sites of recognised value effect on water quality from the proposed SWC reclamation. 4 Overall Impact - / - - ‘Negative – Low / High’. Overall, whilst the medium- term economic viability of oyster farming in the area is not good, the site has been included in the evaluation for the time being. The impact of the proposed island development on mariculture activities may be significant, whilst the cumulative effect on hydrodynamics of the SWC reclamation and island site would deteriorate water quality for oyster farming.
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Impacts Score Commentary
Cultural Heritage Assessment 1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites 2 Potential for archaeological value - There is evidence of land based archaeological finds along the Deep Bay Coastline, suggesting that the coastal area was occupied by early human settlement, and frequented by seafaring people for several thousand years. Recognising the lack of archaeological data currently available for the site, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative Heritage O / - The adjacent land based archaeological sites are Impacts on sites of recognised value coastal in nature. Given their proximity to the site, a reduction in flow along this area, could result in sedimentation and burial of any offshore / intertidal archaeological deposits. 4 Overall Cultural Heritage Impact - The potential impacts on cultural heritage are considered to be ‘Negative – Low’. Whilst there is no direct evidence of cultural heritage remains in the location of the site, the occurrence of remains along the adjacent coastline increases the potential for marine archaeological finds.
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Impacts Score Commentary
Landscape and Visual Impact Assessment 1 Implications for Landscape Planning - While this area of landscape is not directly covered and Designations by any planning designations reflecting landscape values, the landfill will conflict with the intention of the Coastal Protection Area on the adjacent coast. Overall impacts will therefore be Negative – Low. 2 Impacts on Landscape Resources O As the site lies in a marine area, there will be no significant impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral. 3 Impacts on Landscape Character - - The landfill will have substantial impacts open and natural character of the landscape. The somewhat artificial character of the restored landfill, however, will contrast with the generally natural characteristics of the existing coastline. Overall impacts on landscape character will be Negative – High. 4 Visual Impacts - - The site will have a substantial impact on the visual amenity of VSRs in villages located along the Sheung Pak Nai coastline, due to the loss of open and expansive views of Deep Bay, as well as upon distant residential VSRs in Shenzhen and in Tin Shui Wai. Overall visual impacts will be Negative – High.
4 Overall Landscape & Visual Impact - - Overall, landscape and visual impacts will be ‘Negative – High’ for the following reasons:
• There will be indirect impacts on the designated Coastal Protection Area.
• The site is a marine one and so no significant landscape resources are affected;
• The open and natural landscape character of the coastline to the north of Ha Pak Nai will be lost. The artificial characteristics of the island will contrast unfavourably with the natural characteristics of the coastline. • A small number of residential VSRs in villages will have their entire view of Deep Bay removed, whilst large numbers of distant residential VSRs in Tin Shui Wai and Shenzhen will also be affected.
Landfill Gas Assessment 1 Distance between the new / O Tnearest sensitive receivers are >250m from the site. extended landfill and SRs 2 Number of Receivers within 250m O There are no sensitive receivers within 250m of the (i.e. the LFG Consultation Zone) site. 3 Man Made/Natural Pathways for O None. LFG Migration 4 Additional Utilisation of LFG to O There are no potential users of LFG (other than on- Reduce Greenhouse Gas Emissions site use) 5 Overall Landfill Gas Impact O ‘Neutral’
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Table 6.3: Summary of Deep Bay Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact - - Negative – High Overall Waste Management Impact O Neutral Overall Ecological Impact - - Negative – High Overall Fisheries Impact - / - - Negative – Low / High Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - - Negative – High Overall Landfill Gas Impact O Neutral
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Table 6.4 Assessment of Significance of Visual Impacts for Deep Bay Island Landfill During Construction / Operation Phase (Note: All Impacts are adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Construction / High) before Mitigation (Insubstantial, Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR 1 Sha Tu Tsuen 5km Few Small High Moderate Moderate VR 2 Tin Shui Wai 45km Many Intermediate High Moderate to Moderate Substantial VR 3 Lau Fau Shan 2.5km Few Large High Substantial Substantial VR 4 Ngau Hom Shek 1.4km Very Few Large High Substantial Substantial VR 5 Sheung Pak Nai 0.8km Very Few Large High Substantial Substantial VR 6 Ha Pak Nai 1.7km Very Few Large High Substantial Substantial VR 7 Shenzhen (Shekou) 5km Very Many Intermediate High Moderate to Moderate Substantial Occupational VSRs VR 8 Workers at WENT Landfill 1.7km Very Few Intermediate Low Slight to Moderate Slight VR 9 Workers in Black Point 3km Very Few Intermediate Low Slight to Moderate Slight Power Station Recreational VSRs VR 10 Hikers on Castle Peak 5.5km Very Few Small Medium Moderate to Slight Moderate to Slight Peninsula VR 11 Area for Boating, Fishing, 0.5km - 10km Very Few Large Medium Substantial to Moderate Diving and other water (varies) Moderate sports activities Travelling VSRs VR 12 Nim Wan Road Users 1km Few Intermediate Medium Moderate Moderate VR 13 Users of the Proposed 0 - 0.5km Moderate Large Medium Substantial Substantial Shenzhen Western Corridor VR 14 Vessels in Deep Bay > 1km Very Few Small Medium Moderate to slight Slight
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Table 6.5 Assessment of Significance of Visual Impacts for Deep Bay Island Landfill During Afteruse Phase (Note: All Impacts are adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Afteruse High) before Mitigation (Insubstantial, Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR 1 Sha Tu Tsuen 5km Few Small High Moderate Insubstantial VR 2 Tin Shui Wai 4.5km Many Intermediate High Moderate to Slight Substantial VR 3 Lau Fau Shan 2.5km Few Large High Substantial Substantial to Moderate VR 4 Ngau Hom Shek 1.4km Very Few Large High Substantial Substantial to Moderate VR 5 Sheung Pak Nai 0.8km Very Few Large High Substantial Substantial to Moderate VR 6 Ha Pak Nai 1.7km Very Few Large High Substantial Substantial to Moderate VR 7 Shenzhen (Shekou) 5km Very Many Intermediate High Moderate to Slight to Substantial Insubstantial Occupational VSRs VR 8 Workers at WENT Landfill 1.7km Very Few Intermediate Low Slight to Moderate Insubstantial VR 9 Workers in Black Point 3km Very Few Intermediate Low Slight to Moderate Insubstantial Power Station Recreational VSRs VR 10 Hikers on Castle Peak 5.5km Very Few Small Medium Moderate to Slight Slight Peninsula VR 11 Area for Boating, Fishing, 0.5km - 10km Very Few Large Medium Substantial to Moderate Diving and other water (varies) Moderate sports activities Travelling VSRs VR 12 Nim Wan Road Users 1km Few Intermediate Medium Moderate Insubstantial VR 13 Users of the Proposed 0 - 0.5km Moderate Large Medium Substantial Moderate Shenzhen Western Corridor VR 14 Vessels in Deep Bay > 1km Very Few Small Medium Moderate to slight Insubstantial
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7. SHA CHAU ISLAND LANDFILL 7.1 Basic Information Project Title 7.1.1 Sha Chau Island Landfill (SCIL) – marine site M.2. Nature of Project 7.1.2 The Project would form a new marine based waste disposal site in waters located east of Sha Chau and slightly south of the Urmston Road channel (Figure 7.1). 7.1.3 The SCIL would require the construction of an artificial island of approximately 350ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A, Section 3.2.
Location and Scale of Project 7.1.4 The SCIL is located off the southern end of Urmston Road; approximately 3km south of CLP Castle Peak Power Station, 3km north of Chek Lap Kok, and <2km east of Sha Chau. The waters around Sha Chau together with Lung Kwu Chau form the Sha Chau and Lung Kwu Chau Marine Park. Part of the proposed site encroaches into the East Sha Chau Contaminated Mud Disposal Area. 7.1.5 Seabed levels in the vicinity of the artificial island are 6-7m below Chart Datum. There would be no need for dredging works to develop the site because the site is relatively sheltered and so the seawall would not need to be dredged to achieve the required stability. Approximately 100Mcum of fill material will be required to construct the artificial island, with a final site formation level to around +6mPD. The capacity of the landfill site would be 50Mcum.
History of Site 7.1.6 The site is located within open marine waters and is to be entirely formed as part of this project. The western portion of the artificial island site will be in very close proximity to the contaminated mud disposal pits at the east of Sha Chau. There are four mud pits with a total disposal capacity of about 46Mcum. Mud Pits I, II and III have been filled up with contaminated mud and capped with clean sand and mud. A recent CED Study estimated that the still operational Mud Pit IV would be exhausted by late 2007.1 As an interim measure, before a long-term disposal facility is available to accept contaminated muds from 2010, CED is to conduct a site selection study for a proposed contaminated mud disposal facility within the Airport East / East of Sha Chau area that can accept muds between 2007 and 2010. The East of Sha Chau study area for this CED Study overlaps with the proposed location of the artificial island. 7.1.7 The marine waters around Sha Chau, Tree Island and Lung Kwu Chau were designated a SSSI in 1979, and were upgraded to full Marine Park status in November 1996. This designation has resulted in restrictions on fishing activities and on marine vessel speeds in the area due to potential impacts on resident dolphin. There has however been some past works in the area by the Airport Authority that constructed an Aviation Fuel Receiving Facility pier at Sha Chau.
1 CED (2001). Strategic Assessment and Site Selection for Contaminated Mud Disposal.
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Number and Types of Designated Projects Covered 7.1.8 This proposal would qualify as a Designated Project under the five categories listed in Part A, Section 2.1. 7.2 Outline Of Planning and Implementation Programme 7.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 7.2. Assuming landfill operations start in 2017, SCIL would be full during the period 2025 to 2030, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 7.2.2 The proposed site is currently not covered by any statutory town plans. As described in Section 3.3, Town Planning Ordinance procedures to cover the proposed site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 7.2.3 The site is located over part of the East Sha Chau Contaminated Mud Disposal Site, which is a gazetted disposal area. Since December 1992, the East Sha Chau area has been used for contained disposal facilities for contaminated mud arising from the SAR’s dredging and reclamation projects. Mud is disposed of in a series of purpose-built pits or by the backfilling of exhausted sand borrow areas. 7.2.4 Tuen Mun lies to the north of this site and is covered by the Draft Tuen Mun OZP Plan no. S/TM/16 issued in April 2002. The nearest developments to the site in the southwest area of Tuen Mun New Town include the River Trade Terminal, CLP’s Castle Peak Power Station, a cement plant and steel works. A site in Tuen Mun Area 38 has also been reserved for Special Industries and is currently being considered for a Recovery Park for the recycling and reprocessing of waste products. 7.2.5 Chek Lap Kok lies to the south of this site and is covered by the Chek Lap Kok OZP Plan no. S/I-CLK/3. The nearest development to the site in Chek Lap Kok is the northern airport runway of the Hong Kong International Airport. The airport site is protected by a Marine Exclusion Zone. 7.3 Possible Impacts on the Environment 7.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the SCIL are outlined below. Figure 7.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 7.1 and 7.2.
Air Quality 7.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation (following reclamation). • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition, and leachate treatment.
7.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site. The closest being the Tin Hau Temple at Sha Chau that is over 800m away from the site’s western boundary. As such, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated.
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7.3.4 The site is located in open marine waters with no topographic features situated between the site and the nearest ASR at Sha Chau. As such, no accumulation of air pollutants is anticipated. 7.3.5 One project with potential dust generating activities is the proposed Recovery Park at Tuen Mun Area 38, located over 2km from the site, for which the first phase is scheduled for 2004. Castle Peak Power Station, which is approximately 3km away from the site, will be the major source of gaseous emissions (SO2 and NO2) located closest to the site. Green Island Cement Works and Shiu Wing Steel Mill are approximately 2.4km away from the site. However, as these various facilities are located very far from the site and there are no existing or planned ASRs in the vicinity of the artificial island, cumulative impacts are not anticipated. 7.3.6 This is a marine site, and marine vessels will be the mode of transportation for waste delivery to the site. The amount of air pollutants resulting from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 300km. In view of these, the regional impacts associated with the territory-wide waste delivery are considered to be neutral to minor.
Noise 7.3.7 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
7.3.8 No existing or planned noise sensitive receivers (NSRs) have been identified within 300m of the site. 7.3.9 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue for this site. 7.3.10 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the land filling operations. 7.3.11 There will possibly be an interim contaminated mud disposal pit operating between 2007 and 2010. However, given the nature of the activities (controlled sediment disposal) the associated operational noise levels are not expected to be significant. Moreover, no NSRs are identified in the vicinity of the site and thus, no cumulative noise impacts are anticipated. 7.3.12 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 7.3.13 EPD conducts routine marine water and sediment quality monitoring in the Study Area. The three closest water quality monitoring stations to SCIL are: NM3 to the east, NM5 to the north and NM6 to the south, with sediment quality monitoring stations at the same locations: NS3 to the east, NS4 to the north and NS6 to the south.
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7.3.14 Marine water in the area is strongly influenced by nitrogen and phosphorus discharges from the Pearl River and by HKSAR-derived sewage discharges (after preliminary treatment) from three marine outfalls. Despite these influences, there was full compliance with the Water Quality Objectives for dissolved oxygen and un-ionised ammonia for the year 2000. EPD data also shows marine sediment quality to be generally good in the area, with only levels of the metalloid arsenic exceeding the Lower Chemical Exceedance Level.2 Key Issues and Sensitive Receivers 7.3.15 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
7.3.16 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the proposed site. These include:
• Cooling water intake for Castle Peak Power Station; • Cooling water intake for Black Point Power Station; • Cooling water intake for Hong Kong International Airport; • WSD cooling and flushing water intakes at Tuen Mun; and • Gazetted Beaches in Tuen Mun District.
7.3.17 In addition, this area is of significance as a fisheries resource and as part of the core area for the Chinese White Dolphin, Sousa chinensis. Due to the conservation value of the dolphin, the marine waters around the Sha Chau and Lung Kwu Chau were designated as a Marine Park in November 1996. Impacts upon ecological and fisheries resources are assessed separately. 7.3.18 The locations of sensitive receivers are shown in Figure 7.1. Reclamation and Site Formation 7.3.19 During the reclamation and site formation phase of the artificial island, sediment handling may lead to water quality impacts from increased suspended solids and reduced dissolved oxygen. There is also potential for sediment plumes to form and be dispersed by the prevailing current. The extent of the sediment plume dispersal will depend on the size and character of the fill material(s) and specific hydrodynamic conditions. 7.3.20 Given the strength and direction of the prevailing current along Urmston Road (the section immediately to the north of the proposed site), coupled with a background of elevated suspended solids, reclamation and site formation works may potentially generate impacts on water quality sensitive receivers. The WQ sensitive receiver that may be most exposed to potential impacts during the ebb tide is the cooling water intake for the Hong Kong International Airport at Chek Lap Kok. The gazetted bathing area at Butterfly Beach and the WSD seawater abstraction points at Tuen Mun to the east are also close to SCIL. However, generalised current details for the area indicate that these receivers at Tuen Mun are in sufficiently sheltered waters not to be adversely affected (ibid.). 7.3.21 The hydrodynamic and water quality monitoring did not predict any exceedances of SS level with respect to WQO during construction. Elevated SS levels, up to a maximum of 17.40% (Phase 3 construction, dry season period) were identified in the vicinity of the northern end of the Hong Kong International Airport.
2 EPD (2001). Marine Water Quality in Hong Kong in 2000. EPD, Government of the HKSAR – 2001.
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Hydrodynamic Water Quality Impacts Following Island Formation 7.3.22 Hydrodynamic modelling for the study area predicted significant increases in accumulated flows in the East Lamma (up to 12.63%) and Tathong Channel (up to 35.48%) and significant reductions in the West Lamma Channel (up to 19.46%). The presence of the island is predicted to cause small increases in average current velocities (1.12% to 3.00%) in the vicinity of the proposed island. 7.3.23 The modelling results also indicated that the presence of the island would result in small reduction (<3%) in the calculated fluxes across Tai Lam Channel during the dry season: at spring ebb and neap flood periods; and the wet season: at spring flood, neap flood and neap ebb periods. During all the remaining tidal phases, there would be minimal increases in the tidal fluxes across the channel (<0.2%). This implied that the presence of the island would have a general minor reduction of flow through the harbour west area, and consequently, the pollution dispersion capacity of the harbour west area would be slightly reduced. 7.3.24 In the hydrodynamic and water quality and hydrodynamic modelling, 10 sensitive receivers that are close to the site were selected for presentation. Of the 10 chosen indicator points, 6 are located in the North Western WCZ (WD1, WI1, GB1, CW2, CW7, MP3), 1 in the North Western Supplementary WCZ (WD3), 2 in Western Buffer WCZ (FC1, GB2) and 1 in Deep Bay WCZ Outer Subzone (CW1). 7.3.25 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.28 to 7.17mg/L which is above the WQO of 4mg/L and 2mg/L respectively. The percentage differences caused by the presence of the island were insignificant (less than 3%). 7.3.26 The predicted average dry season salinity ranged from 28.21 to 33.14ppt. The differences in salinity levels caused by the presence of the island were minimal (less than 1%) at all of the selected indicator points as compared to the WQO requirements that change due to any waste discharge should not exceed 10% of natural ambient level. 7.3.27 The predicted dry season SS levels at the indicator points were in the range of 5.54 to 10.73mg/L. The percentage increases in the SS levels caused by the island were less than 3%. Comparing to the WQO requirement that any waste discharge should not raise the natural ambient level by 30%, the differences are considered small. 7.3.28 The predicted E.coli in the dry season levels ranged from 1 to 215count/100ml and are below the WQO of 610cfu/ 100ml. Only GB1 showed an increase in the E coli levels of 6.09% while CW7 showed a reduction in the E coli levels of 2.78%. No notable changes were observed at any of the remaining stations. 7.3.29 The predicted average dry season UIA (0.00263 – 0.00433mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L. 7.3.30 The dry season TIN levels ranged from 0.161 to 0.251mg/L. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The calculated annual mean values ranged from 0.272 - 0.281mg/L for FC1, GB2 (Western Buffer WCZ), 0.345 to 0.448mg/L for WD1, WI1, GB1, CW2, CW7, MP3 (North Western WCZ) and 0.463mg/L for CW1 (Deep Bay WCZ Outer Subzone). The annual mean WQO for TIN is 0.4mg/L for Western Buffer WCZ and 0.5mg/L for both North Western WCZ and Deep Bay WCZ Outer Subzone. Therefore, the calculated annual mean TIN values at all the selected indicator points complied with their respective WQO.
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7.3.31 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average and bottom layers ranged from 4.78 to 5.07mg/L and is above the WQO of 4mg/L and 2mg/L respectively. It is predicted that the presence of the island would reduce both the 90%ile depth-averaged DO and 90%ile bottom DO at most of the indicator points. Compared to the baseline water quality results, the percentage differences for both 90%ile depth-averaged DO and 90%ile bottom DO were minimal of less than 1.5% at all indicator points. 7.3.32 The predicted average wet season salinity ranged from 4.50 to 18.17ppt. It is predicted that the island would change the salinity at CW1, WD1, CW7 and CW2 by -11.07%, -9.71%, - 8.42% and +10.71% respectively. Compared to the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level, the differences at these 3 stations are considered quite significant. The differences at all the remaining stations were less than 4%. 7.3.33 The predicted SS levels in the wet season at the indicator points were in the range of 6.97 to 15.69mg/L. It is predicted that the island would increase the SS levels at most of the sensitive receivers with the largest differences of 13.11% predicted at Station CW7. Compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30%, the predicted differences are considered small. 7.3.34 The predicted wet season E.coli levels in the wet season ranged from 1 to 174count/mL and are well below the WQO of 610cfu/100mL. 7.3.35 The predicted average wet season UIA (0.00553 – 0.00674mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L. 7.3.36 The predicted wet season TIN levels were quite high and ranged from 0.382 – 0.688mg/L. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The calculated annual mean values ranged from 0.272 - 0.281mg/L for FC1, GB2 (Western Buffer WCZ), 0.345 to 0.448mg/L for WD1, WI1, GB1, CW2, CW7, MP3 (North Western WCZ) and 0.463mg/L for CW1 (Deep Bay WCZ Outer Subzone). The annual mean WQO for TIN is 0.4mg/L for Western Buffer WCZ and 0.5mg/L for both North Western WCZ and Deep Bay WCZ Outer Subzone. Therefore, the calculated annual mean TIN values at all the selected indicator points complied with their respective WQO. 7.3.37 The water quality modelling results indicated that the water quality impacts due to the proposed island on the Sea Water intake would be minimal. The pollutant levels at WI1 (WSD Sea Water Intake at Tuen Mun) complied with the WQO of Sea Water for Flushing Supply. Cumulative Impacts 7.3.38 Site formation and construction works with the potential for cumulative water quality impacts are reclamation works at Yam O and further development work at Tung Chung. Generalised information on prevailing water currents in the area indicates that works at Tung Chung are unlikely to contribute to cumulative impacts due to weak currents in Tung Chung Bay / south of Chek Lap Kok area, which have limited potential for sediment transport. It is also expected that works at Yam O would be completed some time before the start of development activities for the proposed Sha Chau island site: presently scheduled for around 2010.
Waste Management / Disposal Impacts 7.3.39 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time.
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7.3.40 Various options for construction have been explored for this site and it is anticipated that muds would not need to be excavated to facilitate construction of the outer sea wall, prior to public filling. Upon completion of construction, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 7.3.41 The anticipated volume of materials is as follows:
Volume of public fill that could be accepted for island construction: 100Mcum 7.3.42 Various potentially dangerous materials may be stored, handled and transported to / from the site. Examples include chemicals for wastewater / leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 7.3.43 Regarding GHG emissions, waste delivery to the Sha Chau Site will be by marine vessel which will have a lower GHG emission per kg waste handled, compared to road traffic, given the capacity for a marine vessel is almost 100 times higher than a truck. The cumulative distance between marine RTSs and the site is around 300km. As such, according to the assessment ranking scale (as presented in Section 5), the potential impacts associated with the GHG emissions are considered to be neutral to minor.
Ecology Baseline Conditions 7.3.44 The key significance of the Sha Chau area in ecological terms is its status as part of the core area for activity of the Chinese White Dolphin Sousa chinensis. Due to the conversation value of the dolphin, the marine waters around the Sha Chau and Lung Kwu Chau were designated as a Marine Park in November 1996. 7.3.45 The Sha Chau and Lung Kwu Chau Marine Park covers a marine and coastal area of about 1,200ha, excluding the land area of Sha Chau, Lung Kwu Chau and Pak Chau. In HKSAR waters the core dolphin habitat area also encompasses waters to the north through Urmston Road and around the mouth of Deep Bay and east towards The Brothers. Whilst dolphins are observed in the general North Lantau area throughout the year, the periods of greatest abundance are June through November.3 7.3.46 According to an AFCD Study, the proposed artificial island site is located at the centre of an ecologically important spawning habitat for a number of fish species, including a number of commercially valuable species.4 Species of note in the Sha Chau and Lung Kwu Chau Marine Park include the fish Cynoglossus macrolepidotus, Solea orata and Lateolabrax japonicus, and a range of shrimp species. There are also records of solitary corals in the area, with the hard coral reported at Sha Chau.5
3 AFCD (2001). Marine Conservation: Chinese White Dolphin – Abundance [www.afcd.gov.hk/con_new/homepage.htm]
4 Environmental Resources Management (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to the Agriculture and Fisheries Department, Hong Kong Government.
5 ERM (1995). EIA for Proposed Aviation Fuel Receiving Facility at Sha Chau. For Provisional Airport Authority.
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7.3.47 The predominant benthic infauna taxa in the area is the polychaetes; with this taxa comprising between 40-70% of the community. Molluscs, crustaceans and echinoderms are also well represented.6 The epifauna community in the area was investigated in 1995 and more recently in the May 2001. In both case the survey was by trawling. The 1995 survey reported that crustaceans were most abundant, with 19 species of crab and 13 shrimp / prawns from a total community catch of 69 species. Bivalves and gastropods (snails and sea slugs) were also well represented, with 8 and 10 species respectively.7 The community was similarly structured based on the 2001 survey, still being dominated by crabs, but with diversity of shrimps / prawns and gastropods being more similar (23 and 24 species respectively).8 7.3.48 In May 2002, as part of the mitigation for the temporary aviation fuel line at Sha Chau, the deployment of artificial reefs was completed in the Sha Chau and Lung Kwu Chau Marine Park and the Chek Lap Kok Marine Exclusion Zone. The reefs were designed to enhance fisheries resources and promote marine bio-diversity and feeding opportunities for the Chinese White Dolphins.9 7.3.49 Due to the disposal of contaminated mud at East of Sha Chau, compliance environmental monitoring has been conducted on behalf of CED since opening of the mud pits and will continue until 2 years after closure of Mud Pit IV to ensure that there are no adverse impacts. Due to the level of seabed disturbance in the East Sha Chau it is anticipated that neither a diverse nor abundant benthic community exists. There are however a number of demersal fish species in the area. Direct Habitat Loss 7.3.50 The site footprint covers a surface area of 350ha. The site area is entirely sub-tidal and its benthic community comprises a range of common species. The immediate waters around the artificial island area do not provide a particularly valuable feeding area for marine species, although as the waters form part of the continuous open water habitat that is heavily used by the Chinese White Dolphin loss of the area may be of some ecological significance. Water Quality / Hydrodynamics 7.3.51 The strong water currents that characterise the area, and particularly the waters of Urmston Road to the immediate north of the artificial island, mean that any decline in water quality brought about as a result of site formation and reclamation activities could affect aquatic species. The Chinese White Dolphin that inhabits the area is native to the Pearl River Delta that is characterised by high levels of suspended sediment. Given that sediment levels are naturally high, and that the dolphins feed by echolocation, any increase in suspended solids from the artificial island works is not anticipated to lead to any significant impacts on this species. 7.3.52 Output from the completed numerical modelling exercise predicts a maximum increase in suspended solids levels in the dolphin habitat (WD1) due north (off Castle Peak) to be just 1mg/L to a total concentration of 10.5mg/L (a 12% increase above baseline). Predicted levels above baseline in the Sha Chau & Lung Kwu Chau Marine Park (MP3) are comparable, although there is a greater range of levels due to more exposure to the Pearl River flow.
6 Binnie Consultants (1995). REMOTS and Grab Sample Survey to Assess Benthic Recolonisation following Backfilling at East of Sha Chau Marine Borrow Pit. For CED, HKSAR Government.
7 ERM (1997). EIA Study for Disposal of Contaminated Mud in the East of Sha Chau Marine Borrow Pit. For CED, HKSAR Government.
8 Mouchel (2001a). EM&A for Contaminated Mud IV at East of Sha Chau: Quarterly Report (May – July 2001). For CED.
9 AFCD (2001). Fisheries: Artificial Reefs Programme. [http://www.afcd.gov.hk/fish/ard/webpage/English/index.html].
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7.3.53 Impacts on adult pelagic and particularly demersal fish would be more locally significant due to greater sensitivity to increased suspended sediment levels. As the waters are also an important spawning ground for a number of species, there is potential for a greater impact on less mobile and more physiologically sensitive juvenile fishes. There is also potential for water quality impacts upon the artificial reef programme that has been developed, and particularly at the reefs deployed in the Airport Exclusion Zone some 1.5km southeast. 7.3.54 Given the water depth, the distance of the artificial island site from coastal areas and the absence of sensitive inter-tidal habitats nearby (i.e. mudflat / mangal), no adverse hydrodynamic impacts are anticipated. This assumption is supported by the results of the modelling exercise, with the greatest change for any of the ecological receivers being a 12% increase in suspended solids at WD1 (from a 9.43mg/L baseline to 10.53mg/L), during Phase 2 construction, Dry Season. Marine Vessel Disturbance 7.3.55 Marine transportation of fill and construction material, and operational marine traffic all give rise for potential collision and noise disturbance with these mammals. There is potential for an increase in incidences of vessel collision with dolphins due to the inevitable increase in marine traffic required for site formation / reclamation activities. Dolphins may feasibly be attracted to the area because of temporary feeding opportunities provided by the works (i.e. disturbance of benthic fish by the works), thus increasing the chances of collision.
Fisheries 7.3.56 Fishing activities conducted without a valid permit are prohibited within the Sha Chau & Lung Kwu Chau Marine Park. 7.3.57 Due to their importance as a spawning ground for commercial fisheries resources, the marine waters between Sha Chau & Lung Kwu Chau Marine Park and The Brothers (bounded by the Castle Peak and Chek Lap Kok coastlines), have been recommended for protection.4 These waters cover part of four main “fishing areas” (from west to east): Lung Kwu Sha Chau; Tap Shek Kok; Mong Hau Shek, and The Brothers.10 7.3.58 Of these four fishing areas, The Brothers is the most productive in terms of adult fish, fish fry and value. Adult fish productivity at the Lung Kwu Sha Chau fishing area is also above average for the HKSAR and as such there is some potential for adverse impacts on fisheries from the development of the potential SCIL in these waters. 7.3.59 Commercially valuable fish species in the area include Leiognathus brevirostrus (pony fish), Lateolabrax japonicus (sea bass) and Clupanodon punctatus (gizzard shad), with commercially valuable shrimp species such as Penaeus penicillatus and Metapenaeus ensis also present.11 The Port Survey 96/97 also identified the following species of adult fish that were abundant in the Lung Kwu Sha Chau fishing area: Caranx kalla (shrimp cad); Sardinella jussieu (sardine); and Trichiurus haumela (hairtail). 7.3.60 As stated in the ecology sub-section, artificial reefs have been deployed in the Sha Chau & Lung Kwu Chau Marine Park and in the Airport Exclusion Zone to enhance fisheries productivity in the area. Any decline in water quality may thus generate adverse water quality impacts, and particularly at the reef area in the Airport Exclusion Zone.
Cultural Heritage 7.3.61 There is no immediate evidence of archaeological remains in this area. However the site lies in one of the most important shipping routes to the Pearl River and has been used by seafarers for several thousand years. Archaeological finds dating to the Neolithic Period have been unearthed on the Archaeological Sites of Sha Chau and Lung Kwu Chau.
10 AFCD (1998). Port Survey 96/97. Fisheries Management Division, AFCD. 11 AFCD (2001). Marine Parks Database: Sha Chau & Lung Kwu Chau [http://parks.afcd.gov.hk/marine/mpark/scmp.htm]
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7.3.62 The coastal area of Tuen Mun was developed with early human settlements. During the Tang and Song Dynasties, (960-1279 AD) Guangzhou (Canton) grew into the largest port in China. Tuen Mun has long been of special strategic importance to coastal defence, maritime trade and sea traffic en route to Canton in the historical past. Located on the Pearl River estuary with waterway access to Guangdong Province (and the port of Canton), Tuen Mun Bay was an important harbour for the Persians, the Arabs and the traders from India, Indo-China and East Indies from the 7th century. 7.3.63 Merchant ships previously used to anchor and gather at Tuen Mun before entering the Pearl River. There is a possibility, therefore, that significant marine archaeological remains could be lying on the seabed of this site. 7.3.64 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site, a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 7.3.65 Landscape Planning Designations - this area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 7.3.66 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 7.3.67 Landscape Character - the SCIL lies adjacent to the existing islands of Sha Chau and Lung Kwu Chau at the mouth of the Chi Shui-Men LCA, lying between Lantau Island to the south and the western New Territories to the north (Figure 7.3). It has a relatively contained character with little major shipping passing through it (Figure 7.4). Within the character area are the Brothers, two small sedimentary islands located in the middle of it. Formerly natural landforms, the islands were levelled as part of the construction of the Hong Kong International Airport at Chek Lap Kok and now comprises low, level platforms with a simple grass cover. 7.3.68 There exists potential for significant impacts on landscape resulting from construction/operation works. The SCIL will be incompatible with the existing open character of the LCA and in particular the relationship of Chi Shui-Men to the Pearl River Estuary. During the afteruse phase, these impacts are likely to be reduced slightly as the island begins to appear more natural. As a consequence of this, the long-term impact on landscape character will be substantial/moderate. 7.3.69 VSRs - VSRs affected by the proposals are identified in Tables 7.3 and 7.4. The extent of the project visual envelope is shown in Figure 7.5. Key views of visual receivers are illustrated in Figure 7.6. 7.3.70 The SCIL is located adjacent to heavily populated coastal areas and has a high degree of visibility. It is also adjacent to an important transportation node into the city, namely the Hong Kong International Airport. The key residential VSRs are the high-rise, high density developments at Tuen Mun and Tung Chung (still undergoing development) as well as various locations along the coastal edge. The above mentioned VSRs are identified as they are the closest to the site and will therefore have the largest degree of impact. 7.3.71 Occupational VSRs include the industrial activities at Pillar Point, the Hong Kong International Airport and numerous ferries that cross the area. Recreational VSRs include Butterfly Beach, Lantau Peak and Castle Peak. Of notable importance are the travelling VSRs arriving at Chek Lap Kok, and using the Airport Express and the ferries. For air travellers, although the view is often short in length, it can often be their first of Hong Kong as a new arrival. For this reason, this area has important visual quality as a tourist gateway to the city.
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7.3.72 VSRs will experience works on the landfill (shipping, marine vessels, construction of the bridge and partially constructed island) as relatively close artificial elements reducing open views across Chi Shui-Men and the visual impacts will be generally substantial to moderate. After the restoration of the landfill island, its visual impact will be reduced to moderate overall.
Landfill Gas 7.3.73 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 7.3.74 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source. 7.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 7.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to the Sha Chau site.
Air Quality 7.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 7.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 7.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the artificial island reclamation. Construction procedures, defining the rates and method of dredging and filling taking into account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Waste Management 7.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5). Ecology 7.4.6 Vessel movements in the area should be reviewed to minimize disturbance of and the potential for collision with the Chinese White Dolphin population.
Fisheries 7.4.7 No special measures are recommended for fisheries mitigation. Cultural Heritage 7.4.8 No specific measures are recommended at this stage for the protection of cultural heritage resources.
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Landscape & Visual 7.4.9 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 7.8. Given the proximity of the proposed island landfill to the Hong Kong International Airport flight paths, the orientation of landscape mitigation and choice of appropriate vegetation species should be made with reference to aviation authorities at the full EIA stage.
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7.5 Summary 7.5.1 A summary of the SEA for the potential the SCIL is provided in Tables 7.1 and 7.2.
Table 7.1: Summary of Sha Chau Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive land use O There are no air sensitive receivers (ASRs) within 500m of the site.
2 Presence of topographic features which O The site does not lie within any airshed and could decrease or exacerbate impacts generally experiences wind. It is unlikely that dust or odours would accumulate around the site.
3 Occurrence of meteorological conditions O Wind blows both towards and away from which could exacerbate impacts ASRs. No prevailing wind direction has been identified.
4 Cumulative Impacts of relevant emissions - Whilst there may be dust generated from the (TSP (construction), NOx, CO, SO2 – LFG Recovery Park at Tuen Mun Area 38 and Flare) taking into account ambient Green Island Cement Works, and gaseous conditions emissions from Castle Peak Power Station and Shiu Wing Steel Mill, these are distant sources. Furthermore, there are no ASRs within 500m of the site. Hence no cumulative impacts are anticipated.
5 Total Emissions of Air Pollutants from the O / - Waste will be delivered to the site by marine territory-wide waste transportation vessel and the cumulative distance to be between the RTSs and the site travelled is estimated to be 300km.
6 Overall Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment
1 Distance to areas of noise sensitive land O There are no noise sensitive receivers (NSRs) use within 300m of the site.
2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site (Only applicable if there are NSRs within boundary. Therefore, this criterion is not 300m) applicable.
3 Cumulative Impacts of developments - Depending on the development programme for within 300m the artificial island there may be noisy activities associated with the interim contaminated mud disposal pit. However, there are no NSRs in the works area.
4 Overall Impact O ‘Neutral’
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Impacts Score Commentary
Water Quality Assessment
1 Water Course Diversion O Artificial island. Not relevant.
2 Potential for sediment contaminant - EPD’s marine sediment testing reveals that the release sediment outside the ESC contaminated mud pits is not contaminated. However, as the site would partially overlap with that of the mud pits, there is some potential for disturbance of contaminated mud therein and thus potential for release of contaminated mud into the water column during reclamation works.
3 Potential impacts on WSRs (including - The WQO for salinity is predicted to be increase or exceedance of WQO) exceeded to the north-west of Black Point and in the vicinity of the northern end of Chek Lap Kok airport. Elevated salinity levels are also predicted near Castle Peak Bay and south of Urmston Road.
4 Potential Impacts on Groundwater O Artificial island. Not relevant.
5 Potential Cumulative Impacts O Whilst there are reclamation works scheduled at Tung Chung and Yam O, the hydrodynamics would not generate a cumulative impact. Furthermore, the activities at Yam O (closest to the site) would be completed before the commencement of any construction activities at the site.
6 Overall Impact - Overall the potential for adverse water quality impact is considered as ‘Negative – Low’. There is some potential for disturbance and mobilisation to the water column of contaminated muds due to overlap of the site with the ESC contaminated mud pits. There are also water intakes in the area that may be affected by sediment plume formation and transport.
Waste Management Assessment
1 Balance of Materials (surplus/deficit of + The site could accommodate a large volume of public fill needed for landfill development) public fill (100Mcum) negating the need to import filling material for site formation. This site will not require the dredging of any muds.
2 GHG emissions from mode of transport O / - Waste will be delivered to the site via marine for delivery of waste to the site from RTSs vessel. The distance travelled from marine Mode of transport for delivery of waste to RTS(s) to the site has been estimated to be the site 300km.
3 Overall Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance between the benefit for being able to accommodate surplus C&D material and the relatively larger amount of GHG emissions for the longer distance travelled.
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Impacts Score Commentary
Ecological Assessment
1 Potential for secondary environmental - Model output shows there is some potential for impacts on “Areas of Absolute Exclusion” water quality (suspended sediment) impacts on ecological resources in the Sha Chau & Lung Kwu Chau Marine Park and SSSI – both excluded areas.
2 Affects an important habitat - - The potential island location is within a fish spawning area of ecological importance, and within part of the core dolphin habitat area. Habitat loss and vessel disturbance may be significant.
3 Affects a species of conservation - / - - Whilst the Chinese White Dolphin may be able importance to avoid the works area and frequent other undisturbed waters, the site is located within their core habitat and so there is potential for adverse impacts upon this protected species during site construction and operation.
4 Potential for Cumulative Ecological O It is considered that there is no potential for Impact on sites of recognised value cumulative effects from either the proposed development works at Tung Chung or at Yam O due to water current and the timing of these works relative to activities at the potential Sha Chau island site.
5 Overall Impact - / - - The site is located within an important habitat for fisheries (of ecological value) and forms part of the core area for the Chinese White Dolphin. These pelagic groups however are adapted to the high background concentrations in suspended solids and also have the ability to avoid areas of disturbance at the proposed site. Overall the impact potential is considered to be ‘Negative – Low / High’.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary environmental O There are no “Areas of Absolute Exclusion” in impacts on “Areas of Absolute Exclusion” the vicinity of the works area. 2 Affects an important mariculture/ fisheries - - The site is located in an area regarded as resources (including spawning / nursery economically important for fish spawning, and ground) supports several fish species of commercial value. 3 Potential for Cumulative Fisheries O It is considered that there is no potential for Impacts on sites of recognised value cumulative effects from either the proposed development works at Tung Chung or at Yam O due to water current and the timing of these works relative to activities at the potential Sha Chau island site. 4 Overall Fisheries Impact - The area is of importance as a spawning ground for several commercially valuable fish species. As the extent of the impact zone from site reclamation activities is not expected to infringe on the core area of the fisheries zone, impacts should be limited, so overall: ‘Negative – Low’.
Cultural Heritage Assessment
1 Important cultural (Declared, Deemed or O There are no known sites of cultural heritage Graded sites) / archaeological sites significance. 2 Potential for archaeological value - The site is located in a known shipping route, and there is evidence of land based archaeological finds on adjacent islands of Sha Chau and Lung Kwu Chau. Recognising the lack of archaeological data currently available at the site, it is considered that the likelihood of archaeological remains in this area is good. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative Heritage Impacts O The adjacent land based archaeological sites on sites of recognised value are coastal. Given their proximity to the site, a reduction in flow along this area, could result in sedimentation and burial of any offshore / intertidal archaeological deposits. 4 Overall Impact - ‘Negative – Low’. The nearest sites of cultural heritage value are land based, (on Lung Kwu Chau (3km) and Sha Chau, (1km)). They would not be affected by this development. There are no planned or confirmed projects, which may cause cumulative heritage impacts.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape Planning and O This area of seascape is not covered by any Designations planning designations reflecting landscape / seascape values and so there will be no impact on these values. Overall impacts on landscape designations will therefore be Neutral.
2 Impacts on Landscape Resources O As the site lies in a marine area, there will be no significant impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral.
3 Impacts on Landscape Character - - The site will have a substantial impact on landscape character by reducing the open character of Chi Shui-Men and changing its relationship to the Pearl River Estuary. During the afteruse phase the natural character of the island will increase but the open character will still be adversely impacted upon. Overall impacts will be Negative – High.
4 Visual Impact - - The site is close to two heavily populated residential areas (Tung Chung and Tuen Mun) as well as to the North Lantau Expressway. It will be seen by very significant numbers of VSRs. The landfill will therefore have a significant visual impact and overall impacts will be Negative – High.
5 Overall Impact - - Overall, landscape and visual impacts will be ‘Negative – High’ for the following reasons:
• There are no landscape designations covering the disposal site.
• As a marine site, no significant landscape resources are affected.
• The open landscape character of Chi Shui-Men and its relationship to the Pearl River will be changed with the construction of an island at the opening to this area.
• There are large numbers of residential VSRs surrounding the site that will be adversely impacted upon by the construction and operation of the island landfill. The site is also close to the North Lantau Expressway.
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Impacts Score Commentary
Landfill Gas Assessment
1 Distance between the new / extended O This is a marine site, the nearest sensitive landfill and SRs receivers are >500m from the site.
2 Number of Receivers within 250m (i.e. O There are no sensitive receivers within 250m of Consultation Zone) the site.
3 Man-Made/Natural pathways for LFG O None. Migration
4 Additional Utilisation of LFG to Reduce O There are no potential users of LFG (other than GHG Emissions on-site use)
5 Overall Impact O ‘Neutral’
Table 7.2: Summary of Sha Chau Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - - Negative – High Overall Landfill Gas Impact O Neutral
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Table 7.3 Assessment of Significance of Visual Impacts for Sha Chau Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Construction / High) before Mitigation (Insubstantial, Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR 21 Tung Chung 6km Many Intermediate High Moderate to Substantial to Substantial Moderate VR 28 Residential Tower in Tuen 4.5km Very Many Large High Substantial Substantial Mun VR 29 Siu Lam San Tsuen 7km Few Small High Moderate Moderate VR 30 Ma Wan 12km Few Intermediate High Moderate to Moderate Substantial Occupational VSRs VR 31 Pillar Point Power Station 1.5km Very Few Intermediate Low Slight to moderate Slight and Cement Works VR 22 Hong Kong International 2.2km Few Intermediate Medium Moderate Moderate Airport VR 23 Shekou, Lantau Island and 0.1+km Very Few Intermediate Medium Moderate Moderate Tuen Mun Ferries Recreational VSRs VR 32 Butterfly Beach 3.75km Few Intermediate Medium Moderate Moderate VR 20 Lantau Peak 9km Very Few Small Medium Moderate to Slight Insubstantial VR 11 Area for Boating, Fishing, 0.5 – 10km Very Few Large Medium Substantial to Moderate Diving and other water (varies) Moderate sports activities VR 10 Castle Peak 4.5km Few Small Medium Moderate to Slight Insubstantial Travelling VSRs VR 25 Hong Kong International 0-3km Many Large Medium Substantial to Substantial to Airport Moderate Moderate VR 26 Airport Expressway 7.5km Many Intermediate Low Slight to Moderate Slight VR 27 Shekou, Lantau Island and 0.5 - 3km Few Intermediate Low Slight to Moderate Slight Tuen Mun Ferries
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Table 7.4 Assessment of Significance of Visual Impacts for Sha Chau Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Afteruse High) before Mitigation (Insubstantial, Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR 28 Residential Tower in Tuen 4.5km Very Many Large High Substantial Moderate Mun VR 29 Siu Lam San Tsuen 7km Few Intermediate High Moderate to Slight Substantial VR 30 Ma Wan 12km Few Intermediate High Moderate to Slight Substantial VR 21 Tung Chung 6km Many Intermediate High Moderate to Moderate Substantial Occupational VSRs VR 31 Pillar Point Power Station 1.5km Very Few Intermediate Low Slight to moderate Insubstantial and Cement Works VR 22 Hong Kong International 2.2km Few Intermediate Medium Moderate Slight Airport VR 23 Shekou, Lantau Island and 0.1+km Very Few Intermediate Medium Moderate Slight Tuen Mun Ferries Recreational VSRs VR 32 Butterfly Beach 3.7km Few Intermediate Medium Moderate Slight VR 20 Lantau Peak 9km Very Few Small Low Insubstantial to Insubstantial Slight VR 11 Area for Boating, Fishing, 0.5 – 10km Very Few Large Medium Substantial to Moderate to Slight Diving and other water (varies) Moderate sports activities VR 10 Castle Peak 4.5km Few Small Low Insubstantial to Insubstantial Slight Travelling VSRs VR 25 Hong Kong International 0 - 3km Many Large Medium Substantial to Slight Airport Moderate VR 26 Airport Expressway 7.5km Many Intermediate Low Slight to Moderate Insubstantial VR 27 Shekou, Lantau Island and 0.5 - 3km Few Intermediate Low Slight to Moderate Slight Tuen Mun Ferries
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8. LANTAU NORTH WEST ISLAND LANDFILL 8.1 Basic Information Project Title 8.1.1 Lantau North West Island Landfill (LNWIL) – marine site M.3. Nature of Project 8.1.2 The Project would form a new marine based waste disposal site in waters located within the North West Lantau (Figure 8.1). 8.1.3 The LNWIL would require the construction of an artificial island of approximately 230ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 8.1.4 The LNWIL is located at the north west of Lantau Island, in proximity to Tai O to the east. The Hong Kong International Airport is located approximately 7km to the northeast of LNWIL. 8.1.5 Seabed levels in the vicinity of LNWIL are 7-10m below Chart Datum. There would be no need for dredging works to develop the site. Approximately 65Mcum of fill material will be required to construct the site, with a final site formation level to around +6mPD. The capacity of the landfill site would be approximately 40Mcum.
History of Site 8.1.6 The site is located within open marine waters and would be entirely formed as part of this project. Prior to the “handover” in 1997 the site area was located in Mainland PRC waters. However, post-handover the boundary of the HKSAR was extended 2-4km westward and it is in this zone that LNWIL is located. 8.1.7 There has been no previous development activity within the site area. However, geotechnical site investigations were undertaken nearby to the northeast for the Airport development works, and there is a 240m long sewage outfall from Tai O located to the east of the site. 8.1.8 A Consultancy Study to undertake an EIA for a sheltered boat anchorage at Tai O was completed in the year 2000. The project will involve construction of a 4ha boat anchorage. Associated with the anchorage there will be a breakwater and a promenade with landing on 0.3-0.4ha. reclaimed land. The project will be implemented in December 2002 through March 2005. 8.1.9 The coastal waters are of some conservation significance, although the San Chau SSSI is the only designated conservation site in the vicinity. This SSSI was designated in May 1999 due to coastal vegetation. The protection of the waters off southwest Lantau within a Marine Park / Reserve has been endorsed by the Country and Marine Parks Board.1 Subject to further study, the boundary of the proposed Marine Park / Reserve would be in proximity to Yi O.2 Number and Types of Designated Projects Covered 8.1.10 LNWIL would qualify as a Designated Project under the five categories listed in Part A, Section 2.1.
1 AFCD (1998). Study on the Suitability of Southwest Lantau to be established as Marine Park or Marine Reserve' Commissioned by AFCD, March 1998. 2 PlanD (2001). South West New Territories Development Strategy Review: Recommended Development Strategy - Final Report. July 2001.
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8.2 Outline Of Planning and Implementation Programme 8.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 8.2. Assuming landfill operations start in 2017, LNWIL would be full during the period 2020 to 2025, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 8.2.2 The site is currently not covered by any statutory town plans. As described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 8.2.3 The LNWIL coincides with one of the sites proposed for development under the C&D Materials Study. It is also immediately to the south of an area proposed under the Port Development Strategy Review as one of four sites for a long-term container terminal. This scheme will be reviewed under the Study for the Hong Kong Port - Master Plan 2020 that commenced in July 2002. 8.2.4 The Recommended Development Strategy formulated under the South West New Territories Development Strategy Review identified the potential for developing this area into a religious and recreation node, but with due regard to the conservation and protection of the natural and cultural heritage of the area. A Recommended Outline Development Plan has been developed under the Tai O Revitalisation Study. A boat anchorage has been proposed at Tai O to revitalise the fishing industry of the area. 8.2.5 AFCD has initiated a proposal to designate the waters immediately to the south of this site as a potential Marine Park. In late 1999, a Provincial Nature Reserve was designated by the Guangdong authorities outside SAR waters, to the immediate west of the site. The Reserve was designated for the protection of Chinese White Dolphin. It is proposed to upgrade this nature reserve from provincial to national status. 8.3 Possible Impacts on the Environment 8.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the LNWIL are outlined below. Figure 8.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 8.1 and 8.2.
Air Quality 8.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
8.3.3 There are Air Sensitive Receivers (ASRs) found within a 500m radius from the boundary of this site. These are the Tai O Police Quarters in Tai O (Shek Tsai Po), Tai O Barracks, and village house in Nga Ying Kok, which are some 300m east of the site boundary. There are other ASRs located in Tai O and Yi O San Tsuen which are approximately 0.8km and 1.0km from the site boundary. 8.3.4 The LNWIL lies in an open marine area, with the existing village developments in Tai O located to the east of the site. A sheltered boat anchorage has been proposed to be constructed within Tai O Bay, and current available information indicates that the construction works will continue until end of 2003. This is unlikely to cause any cumulative air quality impacts as the boat anchorage construction will likely be completed well before any works to be commenced at this site, although a check should be carried out at the detailed study stage
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to determine whether the Tai O Sheltered Boat Anchorage project construction programme has been delayed in which case there could be an overlapping of the works. Nonetheless, there are no other known developments (existing or planned) within 5km from the site that will cause any cumulative impacts. Since this site lies in an open marine area, the build up of air pollutants is not anticipated. 8.3.5 This is a marine site and marine vessels will be the mode of transportation for waste delivery to the site. The amount of air pollutants emission from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. However, the estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 490km. Based on the relatively large distance to be travelled, the regional air quality impacts are considered to be moderate.
Noise 8.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
8.3.7 There are Noise Sensitive Receivers (NSRs) found near this site. These are the Tai O Police Quarters in Tai O (Shek Tsai Po), Tai O Barracks, and village house in Nga Ying Kok, which are marginally within 300m radius east of the site boundary. There may be potential noise impacts associated with the reclamation, construction and operation of the landfill facility. Given this distance separation, noise impacts can be significantly reduced by distance attenuation. Mitigation measures requirements will need to be investigated at the later detailed design stage. 8.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. The Area Sensitivity Rating for the NSRs in Tai O area is ‘A’ and so the permissible night time noise limit is 45dBA (for non-designated area under NCO). As such there may be some potential for noise impact should night time works take place. However, night time works will be governed by the Construction Noise Permit system. 8.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. In addition, cumulative noise may result from the operation of the Tai O Sheltered Boat Anchorage development. 8.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 8.3.11 The site is located some 500m off the northwest coast of Lantau Island, and falls within the North Western Supplementary Water Control Zone (WCZ). The water quality in the area is influenced by the flow from the Pearl River Estuary. 8.3.12 Background marine water quality in the area was established using EPD routine monitoring data. Monitoring data for the year 2000 from the nearest marine station (‘NM8’), some 2km northeast of the site, shows full compliance with key WQOs such as dissolved oxygen, TIN,
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un-ionised ammonia and E. Coli. 3 From recent monitoring within Tai O Bay the water quality is good, with relatively low levels of nutrients, organic pollutants and heavy metals, and high dissolved oxygen levels.4 The results also show the importance of tidal flushing in maintaining good water quality by diluting potential water quality pollutants. 8.3.13 The LNWIL is sheltered to the south and east by Lantau Island. During the ebb tide, the current is from the direction of the Pearl River, and flows in a southeast direction. The current changes its direction to southwest and gains in strength as it approaches the western coast of Lantau Island. During flood tide, the current originates from the southern waters of Hong Kong and flows in a reverse direction. It flows from south to north in a north-easterly direction around the site. The tidal currents at the site are strong; up to 1.5m/sec. The flood tide current is generally weaker in magnitude than the current during ebb tide. 8.3.14 No site-specific marine sediment survey has been conducted previously. EPD sediment monitoring data from station ‘NS6’, some 5km to the north-east, indicates that the level of all pollutants in the sediment are less than the Lower Chemical Exposure Limit (LCEL), suggesting that the sediment is uncontaminated. The sediment was deemed suitable for open sea disposal. Since no dredging has been proposed for this site, the potential for impacts associated with mud dredging is not considered significant. Key Issues and Sensitive Receivers 8.3.15 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns). 8.3.16 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the site. These include:
• Secondary contact recreation subzone at the western shoreline of Lantau Island, from Sai Tso Wan to Sham Shek Tsuen; and • Cooling water intake at the east of the Hong Kong International Airport apron.
8.3.17 In addition, there are a range of aquatic and inter-tidal ecological receivers within the vicinity of the site that may be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the ecology and fisheries subsections. The sensitive receivers include:
• Mangrove stands along Tai O Creek (including mangrove habitat creation / enhancement proposals); • Horseshoe Crab habitat near Tai O South and North; • The proposed Marine Parks at South-west Lantau and at Soko Island; • The Sha Chau and Lung Kwu Chau Marine Park; and • Fishing activities
8.3.18 The site also coincides with habitat of the Indo-Pacific Humpbacked (Chinese White) Dolphin, Sousa chinensis. Dolphin activity is concentrated in marine waters around the Lung Kwu Chau and Sha Chau Marine Park. The locations and uses of these sensitive receivers are shown in Figure 8.1.
3 EPD, Marine Water Quality in Hong Kong for 2000, (EPD 2000)
4 Scott Wilson (Hong Kong) Ltd (2000). Tai O Sheltered Boat Anchorage Environmental Impact Assessment - Final Report. For CED, HKSAR Government.
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Reclamation and Site Formation 8.3.19 Based on the preliminary engineering design, no dredging of sediment is proposed for NWLIL. This significantly reduces the extent of any sediment plume likely to be generated and eliminates any pollutant releases to the water column as a result of dredging work. The placement of fill for island construction may still lead to increases in suspended solid levels and reduced dissolved oxygen. 8.3.20 Given the strength and current direction at the site, the WSR’s most exposed to potential impacts from suspended sediment is the secondary contact recreation subzone between Sai Tso Wan and to Sham Shek Tsuen. During Phase 1 construction, marginal compliance with the WQO level increase (30%) was predicted at HC2 (29.23%) to the west of Hung Fai Shek in the dry season. HC3, the Horseshoe Crab area to the North of Tai O, also was predicted to suffer high SS Level (21.23%), although it complied with WQO. During Phase 2 construction, WQO exceedance is predicted during the dry season (40.24%) at HC2 whilst the wet season would remain marginally compliance (24.15%). Predictions for HC3 indicate that the SS levels in this location would remain marginally compliance during the dry season (24.93%). During Phase 3 construction, WQO exceedance is predicted at HC2 during the dry season (53.25%) and wet season (31.29%) and at HC3 (31.18%) during the dry season. Hydrodynamic and Water Quality Impacts Following Island Formation 8.3.21 The presence of an artificial island could locally affect the flow regime in the area. The hydrodynamic and water quality modelling did not predict any obvious difference in the momentary flow between the baseline and operational scenarios for either the wet or dry season. There is also no significant change predicted in the accumulated flow for the East or West Lamma Channels. For the Tathong Channel, however, an increase in accumulated flow of 16.69% is predicted for the wet season. In addition, the modelling predicts that a significant increase in velocity (94% on average) may occur between Tai O Bay and the island. However, the velocity is predicted to decrease further to the north (14% on average). 8.3.22 From the previous studies, it is known that Tai O Bay receives pollutants from various sources including the treated wastewater discharges from the Kau San Tei sewage treatment facility, sewage discharges from Tai O village and from vessels that operate in the area. A reduction in water circulation and flushing in the bay area may increase the residence time for potential water quality parameters such as BOD and E.coli. 8.3.23 In the water quality and hydrodynamic modelling, 5 sensitive receivers that are close to the site were selected for presentation. Of the 5 chosen indicator points, 2 are located in Mainland waters (WD2 and WD3) and 3 in the North Western Supplementary WCZ (HC2, HC3 and MP13). 8.3.24 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.62 to 7.18mg/L and 6.59 to 6.94mg/L respectively which complied with the WQOs of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO as well as the Mainland sea water quality standard of >6mg/L. Compared to the baseline water quality results, the percentage differences in DO caused by the presence of the island were minimal (less than 1%). 8.3.25 The predicted average dry season salinity ranged from 30.12 to 33.10ppt. The differences in salinity levels caused by the presence of the island were minimal (less than 1%) at all the selected indicator points as compared to the WQO requirements that change due to any waste discharge should not exceed 10% of natural ambient level. 8.3.26 The predicted dry season SS levels at the indicator points were in the range of 5.19 to 8.85mg/L. The island would increase the SS levels at MP13, HC3, HC2 and WD2 by 1.37%, 1.11%, 0.72% and 0.36% respectively. Compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 10mg/L, these differences are considered very small.
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8.3.27 The average in the dry season E.coli levels ranged from 1 to 4count/100mL which are well within the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. 8.3.28 The predicted average dry season UIA (0.00263 – 0.00275mg/L) at all indicator points was very small as compared to the WQO of 0.021mg/L for annual mean. The Mainland standard of 0.02mg/L and was comparable to the wet season data. 8.3.29 The dry season TIN levels ranged from 0.097 to 0.173mg/L which are below the annual mean WQO for TIN of 0.3mg/L for North Western WCZ. Since the WQO for TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The annual averaged values ranged from 0.303 to 0.420mg/L which breached the annual mean WQO of 0.3mg/L as well as the Mainland standard of 0.2mg/L. However, the averaged baseline values also exceeded the WQO. 8.3.30 The predicted 90%ile DO for depth average and bottom layer ranged from 4.91 to 5.07mg/L and 4.54 to 4.83mg/L respectively which complied with the WQO of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO. The DO levels predicted at WD2 and WD3 however did not comply with the Mainland standard of >6mg/L. However, the baseline values for these 2 stations also exceeded the Mainland standard. Comparing to the baseline water quality results, the percentage differences in DO caused by the presence of Site M3 were insignificant (less than 2%). 8.3.31 According to the wet season water quality modelling results, the predicted average salinity ranged from 6.17 to 12.09ppt. The differences in salinity levels caused by the presence of the site are small (less than 3%) as compared to the WQO requirements that change due to any waste discharge should not exceed 10% of natural ambient level. 8.3.32 The predicted wet season SS levels at the indicator points were in the range of 9.57 to 13.57mg/L. The percentage changes were within 4% which complied with the WQO of 30% as well as the Mainland standard that man-made increment should not exceed 10mg/L. 8.3.33 The average wet season E.coli levels ranged from 1 to 6count/100mL which were well below the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. 8.3.34 The predicted average wet season UIA (0.00476 – 0.00578mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L as well as the Mainland standard of 0.02mg/L. The largest derivation with the baseline scenario was at HC2 with value of 1.1%. 8.3.35 For the predicted wet season TIN levels, the values were relatively higher as compared to the dry season data and ranged from 0.5095 to 0.667mg/L. Compliance of the predicted values with the annual mean WQO for TIN is discussed in Section 8.3.29 above. Cumulative Impacts 8.3.36 Construction of the proposed Tai O Sheltered Boat Anchorage Area is planned between December 2002 and March 2005. Even if there is a slip in the construction programme the works for the boat anchorage would be completed many years before any works are due to commence for the LNWIL. As such, construction phase cumulative impacts are not anticipated. However, the long-term cumulative impacts on the hydrodynamics and water quality within Tai O Bay could still be significant. The extent and magnitude of cumulative impacts should be considered further at the detailed EIA stage of the project. 8.3.37 There are also further development works proposed at Tung Chung. The ongoing Comprehensive Feasibility Study for the Tung Chung New Town Development indicates that Phase 4 would be completed around 2011, and so there is some potential for works to overlap with reclamation at the proposed island site. Whilst the water current in Tung Chung Bay / south of Chek Lap Kok area is generally weak there would be potential for any sediment arising to be flushed through the confined water “channel” between San Tau and the south airport apron towards the site.
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Waste Management / Disposal Impacts 8.3.38 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 8.3.39 Various options for construction have been explored for this site and it is anticipated that muds would not need to be excavated to facilitate construction of the outer seawall, prior to public filling. Upon completion of construction, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 8.3.40 Anticipated volume of materials are as follows:
• Volume of public fill that could be accepted for island construction: 65Mcum.
8.3.41 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples include chemicals for wastewater / leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 8.3.42 Regarding the GHG emissions, waste delivery to the LNWIL will be by marine vessel which will have a lower GHG emission per kg waste handled compared to road transport given the capacity is almost 100 times larger for a marine vessel than a truck. The cumulative distance between marine RTSs and the site is around 490km as estimated in the Preliminary Marine Review (March 2002). As such, the potential impacts associated with GHG emissions (from waste transportation) are considered to be moderate.
Ecology Baseline Conditions 8.3.43 The Sha Chau and Lung Kwu Chau Marine Park is approximately 7km north of the site at its closest point. The Marine Park was designated in November 1996 with the primary objective of protecting the Chinese White Dolphin Sousa chinensis and its habitat. The dolphin is protected under the Wild Animal Protection Ordinance, under Mainland PRC conservations law (Class I protected species) and is listed on Appendix I of CITES. Other sites of conservation importance in the area are the proposed Marine Parks / Reserves at southwest Lantau and at the Soko Islands. 8.3.44 The benthic community in the vicinity of the site has been investigated through field survey and was reportedly dominated by polychaete worms, with molluscs and crustaceans also abundant.5 Study of the benthic community in Tai O Bay compared to the offshore seabed some 6km north revealed that the density and diversity of the Tai O community was markedly lower. The benthic community in the abandoned saltpans in Tai O was dominated by the polychaetes Mediomastus californiensis, Melinna sp. and Neanthes glandicincta.6 8.3.45 The most significant epibenthic invertebrate to utilize the waters in the vicinity of the site is the Horseshoe Crab Carcinoscorpius rotundicauda. The crab can be found in the shallow sub- tidal waters of northwest Lantau, including Tai O and Yi O, and has been observed to a limited extent on muddy intertidal areas in inner Tai O Bay (ibid.). Other species observed at the Tai O saltpans that are representative of sheltered muddy inter-tidal zones in the HKSAR include the fiddler crabs Uca lactea, U. borealis, and U. arcuata; whilst the Mudskipper Periophthalmus cantonensis and the gastropod Cerithidea rhizophorarum were also abundant. A key component of the shallow water habitats in Tai O Bay is the mangrove habitat, with a variety of mangroves and associates recorded. These include Acanthus
5 Greiner Maunsell (1991). New Airport Master Plan: Environmental Impact Assessment – Final Report. For Provisional Airport Authority – Hong Kong. 6 Scott Wilson (Hong Kong) Ltd (2000). Tai O Sheltered Boat Anchorage Environmental Impact Assessment - Final Report. For CED, HKSAR Government.
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ilicifolius, Acrostichum aureum, Aegiceras corniculatum, Avicennia marina, Bruguiera gymnorrhiza, Clerodendrum inerme, Excoecaria agallocha, Hibiscus tiliaceus and Kandelia candel. 8.3.46 According to an AFCD Study, the LNWIL is located in the vicinity of an ecologically important spawning habitat for a number of fish species, including a number of commercially valuable species7. The ecological linkage with the Marine Park is such that the same range of species is expected in waters around the site. [See also ‘Fisheries’ sub-section below]. 8.3.47 Other ecologically significant areas in the vicinity of the site include the Tai O Egretry that provides breeding sites for the Chinese Pond Heron, Night Heron and Little Egret. There are important wetland sites at Leung Uk marsh (habitat to the rare Rough-skinned Floating Frog) and Tai O reed-bed (one of the largest areas in the HKSAR). Direct Habitat Loss 8.3.48 The site footprint covers a surface area of 230ha and is entirely sub-tidal. The benthic community in the area is comprised of a range of common species, although in more shallow coastal waters near Tai O the seabed is habitat to the Horseshoe Crab, Carcinoscorpius rotundicauda, which is of limited distribution in the HKSAR. It is quite possible that the range of this species in the NW Lantau area overlaps in part with that of the site footprint. Any impact on the breeding ground of this species may be reflected in ecosystem dynamics in other areas such as Tai O and Yi O. 8.3.49 The waters around LNWIL form part of the continuous open water habitat that is heavily used by the Chinese White Dolphin. The coastal waters around the site are also of importance to fisheries in the area. Water Quality / Hydrodynamics 8.3.50 The Chinese White Dolphin that inhabits the area is native to the Pearl River Delta that is characterised by high levels of suspended sediment. Given that sediment levels are naturally high, and that the dolphins feed by echolocation, any increase in suspended solids from reclamation activities is not anticipated to lead to any significant impacts on this species. This initial assumption is supported by the output of the hydrodynamic and water quality modelling exercise, with only a marginal increase in suspended solids levels (by < 1mg/L) in the dolphin habitat to the north (WD3). Impacts on adult pelagic and particularly demersal fish would be more locally significant due to greater sensitivity to increased suspended sediment levels. As the waters are also an important spawning ground for a number of species, there is potential for a greater impact on less mobile and more physiologically sensitive juvenile fish. 8.3.51 Of greater potential for adverse impact is the effect of smothering and hydrodynamic change on inter-tidal habitats and the benthic community. Soft inter-tidal habitats that are most prone to sedimentation exist at Tai O and Yi O (e.g., mudflat / mangrove). The LNWIL would also be across the mouths of Tai O and Yi O bays; and in waters used by the Horseshoe Crab. The numerical model predicts a potentially significant increase in suspended solids levels in coastal waters north and south of Tai O. Suspended solids levels at the Horseshoe Crab habitat to the north (HC3) are predicted to increase by up to 2.5mg/L over baseline to around 10mg/L, whilst levels to the south (HC2) may increase by 3.5mg/L to around 11mg/L. Whilst these absolute concentrations are not great, the effects on visibility / Horseshoe Crab feeding habit are unknown. 8.3.52 The results of modelling do not indicate that there would be any adverse ecological effects on the potential Marine Park / Marine Reserve at Southwest Lantau from the site, or on any of the ecological receivers once the island has been constructed.
7 Government Environmental Resources Management (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to the Agriculture and Fisheries Department, Hong Kong.
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Marine Vessel Disturbance 8.3.53 Marine transportation of fill and construction material, and operational marine traffic all give rise for potential collision and noise disturbance with these mammals. There is potential for an increase in incidences of vessel collision with dolphins due to the inevitable increase in marine traffic required for site formation / reclamation activities. Dolphins may feasibly be attracted to the area because of temporary feeding opportunities provided by the works (i.e. disturbance of benthic fishes by the works), thus increasing the chances of collision.
Fisheries 8.3.54 The closest designated fishing areas to the LNWIL are Shum Wat (0017) and Sha Lo Wan (0018). “Shum Wat” is the nearest of the two areas to the LNWIL, but there is no overlap with the site. Data from the Port Survey 96/97 undertaken by AFCD shows these fishing areas to be ranked 34th and 75th for adult fish productivity (per hectare) respectively.8 The “catch value” ranking is almost identical (34th and 77th, respectively). As such, compared to the deduced HKSAR-wide average as shown in Table 7.1, these fishing areas – particularly Shum Wat – are “productive”. Amongst the most important adult fish species caught in the Shum Wan fishing area (by weight) are: Caranx kalla (shrimp cad); Argysomus spp. (croaker); Sardinella jussieu (sardine); and Trichiurus haumela (hairtail). 8.3.55 With defined areas of spawning importance to the northeast and the south of Lantau, the LNWIL is located in proximity to waters beyond the immediate LNWL footprint that are important spawning grounds for a range of commercially valuable fish and crustaceans. The species of commercial value that spawn in these waters include the fish Leiognathus brevirostrus, Lateolabrax japonicus, Clupanodon punctatus, Johnius belengeri and the shrimp Metapenaeus joyneri. Commercially valuable shrimp species such as Penaeus penicillatus and Metapenaeus ensis are also found toward the Sha Chau and Lung Kwu Chau Marine Park.9 8.3.56 Given that these spawning areas fall on either side of the site, it is likely that the waters immediately around the site are also of comparable economic importance. This is supported by the fact that Tai O has a seafood industry that supports its fishing community. Some local fishermen sell their catches directly in the Tai O market while some deliver their catches to food processing companies for the production of salted fish and shrimp paste that are famous products of Tai O. Modelling results predict that there may be localised increases in suspended solids around the coastline north and south of Tai O. There is thus some potential for adverse impacts on coastal fisheries resources. 8.3.57 There are no fish culture zones in the vicinity of the site: the nearest being at Ma Wan off northeast Lantau.
Cultural Heritage 8.3.58 There is no immediate evidence of archaeological remains in this area. However the site lies adjacent to Tai O, which has recognised historical significance. 8.3.59 Tai O Bay is strategically located at the heart of the Hong Kong-Macau-Guangzhou triangle. As this area provides an excellent natural harbour, it has been the focus for a range of maritime activities over the years. 8.3.60 Archaeological discoveries indicate that the western shore of Lantau was occupied by early human settlement. A number of archaeological sites have been identified, such as the Tai O and Yi O Archaeological Sites. This also suggests that the earliest inhabitants were seafarers, making frequent landings ashore.
8 AFCD (1998). Port Survey 96/97. Fisheries Management Division, AFCD 9 AFCD (2001). Marine Parks Database: Sha Chau & Lung Kwu Chau [http://parks.afcd.gov.hk/marine/mpark/scmp.htm]
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8.3.61 Archaeological discoveries made on Lantau show that the island has had settlements since Neolithic times. Fishing, salt making and lime burning were the three main industries of the island for many centuries. Salt production in intertidal salt lagoons at Tai O is one of the earliest industrial activities recorded in Hong Kong and there is evidence of these activities dating from the 18th Century. 10 8.3.62 Tai O was one of the six guard stations established for land based coastal defence of Hong Kong during the Ming Dynasty. It was also a guard station during the late Ching Dynasty. 8.3.63 A marine archaeological investigation was carried out in 2000, in the inner harbour of Tai O under the recommendations of the Sheltered Boat Anchorage EIA, (Ibid) no artefacts or relics were found. 8.3.64 Recognising the rich history of this area and the likelihood of archaeological remains in this area, a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 8.3.65 Landscape Planning Designations - this area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 8.3.66 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 8.3.67 Landscape Character - the site is located in the Pearl River Estuary LCA on the northwestern coast of Lantau Island, adjacent to the harbour entrance of Tai O (Figures 8.3 and 8.4). The Pearl River Estuary LCA has a remote and exposed character, broken by frequent ferries and occasional shipping. The coastline of Lantau in this area is dramatic and natural. Scattered along the coastline are small, steep rising granitic islands. 8.3.68 There exists potential for substantial impacts on landscape resulting from construction/operation works that will introduce new elements that are incompatible with the existing natural landscape. The location of the island landfill will impact upon the relationship of Tai O to the Pearl River Estuary as well as substantially contrasting with the natural quality of the adjacent Lantau uplands and coastline. Upon completion of the LNWIL landfill and the commencement of the afteruse phase, these impacts are likely to be reduced somewhat, as the completed island is restored. The somewhat artificial character of the island however will still be inconsistent with the natural character of the surrounding landscape. As a consequence of this, the long-term impact on landscape character will be substantial to moderate. 8.3.69 VSRs - VSRs affected by the site are identified in Tables 8.3 and 8.4 the extent of the project visual envelopes is shown in Figure 8.5. 8.3.70 Although not located close to any densely populated VSRs, the site will impact substantially upon the residential VSRs of Tai O, Ching Ting and Shek Tsai Po Peninsula. Recreational VSRs include users of trails on Lantau while travelling VSRs will include passengers on the Tai O and Macau ferries and passengers on aircraft using Hong Kong International Airport. 8.3.71 VSRs will experience works on the landfill (shipping, marine vessels, and partially constructed island) as relatively close artificial elements contrasting with the natural, coherent qualities of the existing landscape. Open views from Tai O and Shek Tsai Po will be the most notably effected with a loss of open views connecting the area to the Pearl River Delta. Resulting aggregate visual impacts will be substantial to moderate. After the restoration of the landfill, its
10 Scott Wilson (Hong Kong) Ltd (2000) Tai O Sheltered Boat Anchorage Environmental and Drainage Impact Assessment, EIA-Final Assessment Report. Civil Engineering Department, Hong Kong Government.
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visual impact will be reduced to moderate to slight for more distant VSRs, while impacts will remain substantial for those such as VSRs in Tai O who are close to the site (Figure 8.6).
Landfill Gas 8.3.72 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 8.3.73 Given the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source. 8.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 8.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to LNWIL.
Air Quality 8.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 8.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5). Night time construction works, if any, will be controlled by a Construction Noise Permit procedure.
Water Quality 8.4.4 Mitigation is likely to be required to prevent impacts during filling for the reclamation for the island. Construction procedures, defining the rates and method of filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments. 8.4.5 Where long term cumulative hydrodynamic and water quality impacts are proved to exist within the Tai O Bay, the setting and shape of the island may need to be modified in the detailed design stage.
Waste Management 8.4.6 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 8.4.7 Vessel movements in the area should be reviewed to minimize disturbance of and the potential for collision with the Chinese White Dolphin population.
Fisheries 8.4.8 There are no special measures recommended for fisheries mitigation.
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Cultural Heritage 8.4.9 No specific measures are recommended at this stage for the protection of cultural heritage resources. Landscape & Visual 8.4.10 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 8.8. Given the proximity of the site to the Hong Kong International Airport flight paths, the orientation of landscape mitigation and choice of appropriate vegetation species should be made with reference to aviation authorities at the full EIA stage.
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8.5 Summary 8.5.1 A summary of the SEA for the LNWIL is provided in Tables 8.1 and 8.2:
Table 8.1: Lantau North West SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive - Tai O Police Quarters, Tai O Barracks, and a small land use number of village houses in Nga Ying Kok are within 500m of LNWIL site.
2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours would or exacerbate impacts accumulate around the site.
3 Occurrence of meteorological O Wind blows both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts
4 Cumulative Impacts of relevant O The site is located in open marine waters to the south emissions (TSP (construction), west of Hong Kong International Airport. The proposed NOx, CO, SO2 – LFG Flare) Tai O Sheltered Boat Anchorage will be constructed in Tai taking into account ambient O Bay and completed in Year 2003. Therefore, it is unlikely conditions that there will be overlapping of construction works with the LNWIL. No other known developments that have relevant emissions in the site vicinity. Hence no cumulative impacts are anticipated.
5 Total Emissions of Air Pollutants - Waste will be delivered to the site by marine vessel and from the territory-wide waste the cumulative distance to be travelled is estimated to be transportation between the RTSs 490km. and the site
6 Overall Impact O / - Given the presence of ASRs within 500m and the potential for regional air quality impacts (due to the long distance to be travelled for waste delivery), the overall impacts are considered to be ‘Neutral / Negative – Low’.
Noise Assessment
1 Distance to areas of noise O Tai O Police Quarters, Tai O Barracks, and a small sensitive land use number of village houses in Nga Ying Kok are some 300m of LNWIL. At night time the BNL for these NSRs is reduced to 45dBA and there is a potential for noise impacts.
2 Topographic Features O / - The site is located within open marine waters. No particular features are found between NSRs and the site. (Only applicable if there are However, NSRs are located marginally within 300m from NSRs within 300m) site boundary.
3 Cumulative Impacts of O / - The proposed Tai O Sheltered Boat Anchorage will be developments within 300m constructed in Tai O Bay and completed in Year 2003. Therefore, it is unlikely that there will be overlapping of construction works with the LNWIL. However, there may be cumulative noise during the operational phase.
4 Overall Impact O / - ‘Neutral / Negative – Low’
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O As a marine site, no watercourse diversions are required. 2 Potential for sediment O No dredging (neither for reclamation nor seawall contaminant release construction) has been proposed for this site. As such, the release of sediment bound contaminants from the dredging work is not anticipated. 3 Potential impacts on WSRs - - Filling may result in a localised increase in suspended solids level in the water column. No dredging has been proposed and this together with placing the fill materials within a confined cell unit will reduce the extent of sediment plume.
It is predicted that both DO and TIN standards in the operational phase would be breached, however, these were both breached in the baseline scenario and the elevations due to the presence of island were not significant, therefore, the island would not be the cause of the exceedances. 4 Potential Impacts on O As a marine site, so there are no groundwater issues. Groundwater 5 Potential Cumulative Impacts - / - - The Tai O sheltered boat anchorage development will be (Potential for concurrent projects completed prior to the construction of LNWIL and so to exacerbate preceding there is no potential for cumulative construction phase impacts) effects. However, given the close proximity of the island to Tai O Bay, there may be cumulative effects on hydrodynamics in the Bay area with associated potential for decreased flushing capacity and water quality decline.
Further development works at Tung Chung may also contribute to water quality impacts in the area transmitted through the semi-enclosed channel between the San Tau and the south of the airport apron. 6 Overall Impact - ‘Negative – Low’. There are potential impacts on the secondary contact zone from sediment plume formation / transport along the nearby coastline. Water quality modelling predicts WQO exceedance for SS to the north and south of Tai O Village during construction. No other WQO exceedance is anticipated.
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Impacts Score Commentary
Waste Management Assessment
1 Balance of Materials + The site could accommodate a major volume of public fill (surplus/deficit of public fill (65Mcum) negating the need to import filling material for needed for landfill development) site formation. This site will not require the dredging of any muds.
2 GHG emissions from mode of - Waste will be delivered to the site via marine vessel transport for delivery of waste to marine vessel. The distance travelled from marine the site from RTSs RTS(s) to the site has been estimated to be 490km.
3 Overall Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance out of the benefit for being able to accommodate C&D surplus materials and the relatively larger amount of GHG emissions for the longer distance travelled.
Ecological Assessment
1 Affects a protected Area O The modelling results predict that there would be no (Protected areas are ‘Areas of construction or operational effects upon the water quality Absolute Exclusion’ – this or hydrodynamics in the proposed South-West Lantau assumes no land take) Marine Park / Reserve.
2 Affects an important habitat - - The shallow sub-tidal and inter-tidal habitat to the north and south of Tai O is important for the Horseshoe Crab. The coastal waters are also well utilised by the Chinese White Dolphin that would suffer habitat loss.
3 Affects a species of conservation - - Whilst the Chinese White Dolphin may be able to avoid importance the works area and frequent other undisturbed waters, the site is located within their core habitat and so there is potential for adverse impacts upon this protected species during site construction and operation. The coast is also a habitat of the Horseshoe Crab.
4 Potential for Cumulative - / - - There is slight potential for cumulative impacts on dolphin Ecological impacts on sites of use in the area from future works at Tung Chung, but recognised value greater potential for disturbance of shallow sub-tidal and inter-tidal habitat that is used by the Horseshoe Crab and a diverse benthic community.
5 Overall Impact - - ‘Negative – High’. The site is located within an important habitat for Horseshoe Crabs, whilst the area is part of the range of the protected Chinese White Dolphin.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary O There are no “Areas of Absolute Exclusion” in the vicinity environmental impacts on “Areas of the works area. of Absolute Exclusion” 2 Affects an important mariculture - / - The site is located in the vicinity of waters that are of / fisheries resources (including economic importance for fish spawning, whilst Tai O Bay spawning / nursery ground) may be of limited importance as a nursery for certain fish species of commercial value. 3 Potential for Cumulative - /- - There is some potential for cumulative impacts on Fisheries Impacts on sites of fisheries in outer Tai O and along the NW Lantau coast recognised value between Tai O and Tung Chung from future development of Tung Chung. 4 Overall Impact - The broader area is of importance as a spawning ground for several commercially valuable fish species, and there is some potential for cumulative effects. There are however no protected fisheries areas immediately around the site, and so overall impacts will be limited: ‘Negative – Low’.
Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites
2 Potential for archaeological - The site is located adjacent to Tai O, a natural harbour value with a recognised maritime history and evidence of early salt production and fortifications. It is considered that the likelihood of archaeological remains in this area is high. A detailed marine archaeological investigation should be carried out in any future studies.
3 Potential for Cumulative O / - The adjacent land based saltpans are intertidal. Given Heritage Impacts on sites of their proximity to the site, a change in flow characteristics recognised value through Tai O Creek could result in sedimentation or erosion of these cultural relics.
4 Overall Impact - ‘Negative – Low’. The nearest area of cultural heritage value is Tai O (<1km), which is recognised for its cultural heritage value through a long history of salt production, trade and fortification. The integrity of relic intertidal saltpans is at risk in the event of changes in hydrodynamic regime of Tai O Creek.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts on landscape designations will therefore be Neutral.
2 Impacts on Landscape O As the site lies in a marine area, there will be no Resources significant impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral.
3 Impacts on Landscape - - The island landfill will have a substantial impact on the Character natural character of the Lantau Coastline. The island will impact on the relationship of Lantau to the Pearl River Estuary. Overall impacts on landscape character will therefore be Negative – High.
4 Overall Visual Impacts - / - - Although, the visual envelope is not heavily populated, the island will have substantial visual impacts on those residential receivers in close proximity to it. These substantial impacts will last throughout the afteruse phase and will include significant visual impacts on some VSRs, notably residents in Tai O. Overall visual impacts will therefore be Negative – Low/Moderate.
5 Overall Impact - / - - Overall the landscape impacts are considered to be ‘Negative – Low / High’ for the following reasons:
• There are no landscape designations covering the disposal site.
• As the site is a marine one, no significant landscape resources are affected.
• There will be significant impacts on the natural character of the Lantau coast and on the relationship of Tai O to the Pearl River Estuary.
• Small numbers of VSRs (at Tai O and Shek Tsai Po) will experience very substantial visual impacts.
Landfill Gas Assessment
1 Distance between the new / O The nearest sensitive receivers are >250m from the site. extended landfill and SRs
2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. Consultation Zone)
3 Man made/Natural Pathways for O None. LFG Migration
4 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce GHG Emissions use)
5 Overall Impact O ‘Neutral’
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Table 8.2: Summary of Lantau North West Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O / - Neutral / Negative – Low Overall Water Quality Impact - Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - - Negative – High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - / - - Negative – Low / High Overall Landfill Gas Impact O Neutral
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Table 8.3 Assessment of Significance of Visual Impacts for Northwest Lantau Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Construction / High) before Mitigation (Insubstantial, Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR 33 Residents at Tai O and 1.5km Many Large High Substantial Substantial Environs VR 34 Residents at Ching Ting 3.5km Few Intermediate High Moderate to Moderate Substantial VR 35 Residents at Shek Tsai Po 0.5km Few Large High Substantial Substantial Peninsula Occupational VSRs VR 36 Fishing Boats at Tai O 0.5km Few Large Low Moderate Moderate to Slight Recreational VSRs VR 33a Visitors at Tai O and 1.5km Many Large Medium Substantial to Substantial to Environs Moderate Moderate VR 34a Visitors at Ching Ting 3.5km Few Intermediate Medium Moderate Moderate to Slight VR 35a Visitors at Shek Tsai Po 0.5km Few Large Medium Substantial to Substantial to Peninsula Moderate Moderate VR 20 Hikers at Lantau Peak 5km Few Intermediate Medium Moderate Moderate to Slight VR 37 Hikers within Lantau North 3km Very Few Intermediate Medium Moderate Moderate County Park VR 38 Hikers at Coastal Footpath 1km Very Few Large Medium Substantial to Substantial to between Yi O and Tai O Moderate Moderate VR 11 Area for Boating, Fishing, 0.5 - 10km Very Few Large Medium Substantial Substantial Diving and other water sports activities VR 39 Hikers at Coastal Footpath 1km Very Few Large Medium Substantial to Moderate between Kau San Tei and Moderate Sha Lo Wan Travelling VSRs VR 40 Passengers aboard Hong 5.5km Moderate Intermediate Medium Moderate Moderate to Slight Kong - Macau Ferries VR 25 Passengers aboard Aircraft N/A Moderate Intermediate Medium Moderate Moderate approaching / departing Chek Lap Kok Airport VR 41 Tai O Ferry 0.5km Few Intermediate Medium Moderate Moderate
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Table 8.4 Assessment of Significance of Visual Impacts for Northwest Lantau Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx. Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Between (order of Impact During (Low, Medium, Significance Residual Impacts VSR VSR and magnitude only) Afteruse High) before Mitigation (Insubstantial, Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR 33 Residents at Tai O and 1.5km Many Large High Substantial Substantial Environs VR 34 Residents at Ching Ting 3.5km Few Intermediate High Moderate to Moderate to Slight Substantial VR 35 Residents at Shek Tsai Po 0.5km Few Large High Substantial Substantial Peninsula Occupational VSRs VR 36 Fishing Boats at Tai O 0.5km Few Large Low Moderate Slight Recreational VSRs VR 33a Visitors at Tai O and 1.5km Many Large Medium Substantial to Substantial to Environs Moderate Moderate VR 34a Visitors at Ching Ting 3.5km Few Intermediate Medium Moderate Slight VR 35a Visitors at Shek Tsai Po 0.5km Few Large Medium Substantial to Substantial to Peninsula Moderate Moderate VR 20 Hikers at Lantau Peak 5km Few Intermediate Medium Moderate Slight VR 37 Hikers within Lantau North 3km Very Few Large Medium Substantial to Slight County Park Moderate VR 38 Hikers at Coastal Footpath 1km Very Few Large Medium Substantial to Slight between Yi O and Tai O Moderate VR 11 Area for Boating, Fishing, 0.5 - 10km Very Few Large Medium Substantial to Moderate to Slight Diving and other water Moderate sports activities VR 39 Hikers at Coastal Footpath 1km Very Few Large Medium Substantial to Moderate to Slight at Fu Shan, Tai O Moderate Travelling VSRs VR 40 Passengers aboard Hong 5.5km Moderate Intermediate Medium Moderate Insubstantial Kong - Macau Ferries VR 25 Passengers aboard Aircraft N/A Moderate Intermediate Medium Moderate Insubstantial approaching / departing Chek Lap Kok Airport VR 41 Tai O Ferry 0.5km Few Intermediate Medium Moderate Moderate
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9. SOKO ISLANDS LANDFILL 9.1 Basic Information Project Title 9.1.1 Soko Islands Landfill Site, (SIL) – marine site M.4. Nature of Project 9.1.2 The Project would form a new marine based waste disposal site adjacent to the Soko Islands, (Figure 9.1). 9.1.3 The SIL would require construction of an artificial island of approximately 475ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. 9.1.4 Construction works would be as described in Part A, Section 3.2. In addition works for SIL would include: - Dredging of 8Mcum of underlying muds for seawall construction.
Location and Scale of Project 9.1.5 The SIL is situated 1.5km to the west of the Soko Islands and about 3km south of the Shek Pik Reservoir on Lantau Island. Seabed levels in this area vary from 5 to 20m below Chart Datum, (the deeper waters coincide with an area previously dredged as part of the West Soko’s Marine Borrow Area). This site is bound by the SAR boundary to the south and west, a major shipping channel to the north and the proposed Soko Islands Marine Park to the east. 9.1.6 The SIL would cover an area of 475ha to an elevation of +6 mPD. The artificial island would accommodate a landfill with a capacity of 75Mcum to an elevation of +56 mPD. The site would accommodate approximately 125Mcum of fill material.
History of Site 9.1.7 The site includes the West Soko’s Marine Borrow Area, enclosing partially exploited sand borrow pits (9Mcum of sand was extracted for the Hong Kong International Airport). It is understood that sand extraction activities are no longer carried out.
Number and Types of Designated Projects Covered 9.1.8 The SIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. The site is in close proximity to a potential Marine Park around the Soko Islands, (see Figure 9.1). Therefore, the site may also qualify as a Designated Project under the following Clauses of Schedule 2 of the EIA Ordinance:
C2 Reclamation of > 1ha (including associated dredging works), a boundary of which is less than 500m from an existing or planned Marine Park or Reserve.
9.2 Outline of Planning and Implementation Programme 9.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 9.2. Assuming landfill operations start in 2018, SIL would be full during the period 2030 to 2035, depending upon the rate of waste arisings and the number of other landfills operating concurrently.
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9.2.2 The proposed site is currently not covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the proposed site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. The area lies just to the south of a site being studied for designation as a Fisheries Protection Area. 9.2.3 This site falls within the boundary of the study area of the South West New Territories Development Strategic Review (SWNTDSR). The SWNTDSR identified the coastal waters off south west Lantau, Soko Islands and South Lamma as potential Marine Parks. The waters around the Soko Islands were identified in the Territorial Development Strategy Review as having high potential recreational / ecological value, and as a significant area for marine ecology. The planning intention of this Marine Park is to protect and conserve the relatively unspoilt marine environment, and provide recreational and educational opportunities to the public in areas, as appropriate. The area of the Soko Islands (particularly Tai A Chau) is being actively considered for resort develop opportunities by the Commissioner for Tourism. In addition, preparation works for the designation of the waters off Southwest Lantau and Soko Islands as Marine Parks are at their final phase. 9.3 Possible Impacts on the Environment 9.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of SIL are outlined below. Figure 9.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 9.1 and 9.2.
Air Quality 9.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation (following reclamation). • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
9.3.3 No air sensitive receivers have been identified within 500m of the site. There are no residents on the Soko Islands and the nearest ASRs are on South Lantau at Chung Hau, (Sha Tsui Detention Centre and Shek Pik Prison) at a distance of approximately 4km. Significant air quality impacts are not anticipated. However, potential operational phase air quality impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other landuses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. Afteruse issues are not considered further in the SEA. 9.3.4 This is a marine site and marine vessels will be used for waste delivery to the site. The amount of air pollutants resulting from the territory-wide waste delivery to the site is anticipated to be less compared to a land based site that relies on road transport. However, the estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 440km. Given the distance to be travelled and the benefit of the use of marine transport, the regional impacts of waste transportation is considered to be moderate.
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Noise 9.3.5 The reclamation and landfill development has the potential to cause the following noise impacts:
• construction – from dredging, tipping, piling works and general construction activities; • operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
9.3.6 No noise sensitive receivers have been identified within 300m of the site, the nearest NSRs are on South Lantau at Chung Hau, (Sha Tsui Detention Centre and Shek Pik Prison) at a distance of approximately 4km. Significant noise impacts are not anticipated. However, potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other landuses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 9.3.7 Whilst it is not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an off-shore site with no noise sensitive receivers in the vicinity, the more stringent requirements for noise emissions during the evening and night time periods are not expected to be an issue for this site. 9.3.8 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 9.3.9 The site is located within the Southern Water Control Zone (WCZ). The current through this area mainly flows in a south-east / north-west and north-west / south-east direction. Background water quality conditions have been established from EPD routine monitoring stations, the latest available data are that collected in 2000, (EPD 20011). The site is situated in the western waters of Hong Kong which are characterised by elevated levels of suspended solids, (compared to Eastern Waters) as a result of the influence of the Pearl River Estuary. Locations of the nearest water quality monitoring stations (SM20 and SM17) are presented in Figure 9.1. 9.3.10 Water quality data for 2000 at the monitored stations indicates full compliance with the Southern WCZ Water Quality Objectives (WQOs) for key parameters such as dissolved oxygen, (DO), E. Coli, and un-ionised ammonia. However, levels of total inorganic nitrogen (TIN) exceeded WQOs at both stations. 9.3.11 The nearest regular EPD sediment monitoring station in this area is SS6, which lies approximately 5km to the east. Sediments at SS6 are considered to be uncontaminated according to EPD data. The potential for impacts associated with marine muds is considered limited. Water quality modelling is being carried out separately and will be included in separate reporting.
1 EPD (2001) Marine Water Quality in Hong Kong (in 2000). Environmental Protection Department, Hong Kong Government.
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Key Issues and Sensitive Receivers 9.3.12 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
9.3.13 Sediment plumes may have some influence on beaches on south Lantau. However, as these sensitive receivers are not along the main flow path, impacts are anticipated to be minor. 9.3.14 The area north of Soko Island has no other WQSRs within 1,000m, the nearest gazetted beach is on Lantau Island – Tong Fuk which is over 6.8km away. Other beaches on Lantau Island include Cheung Sha Upper (7.6km), Cheung Sha Lower (8.8km) and Pui O (11.0km). Reclamation and Site Formation 9.3.15 Due to the exposed location of the site, localised dredging is likely to be necessary for the seawalls prior to construction of the reclamation. However, the dredged material can be placed within the existing gazetted Soko Islands borrow area (within the footprint of the reclamation) reducing transport and spillage losses. 9.3.16 The placement of fill for island construction is also likely to lead to localised increases in suspended solid levels. Hydrodynamic and Water Quality Modelling predicts that the WQO for increase in SS would be exceeded at SC19 (36.09%), to the north of the Soko Islands during the dry season period in Phase 3 construction. Whilst not exceeding WQO, raised levels of SS were predicted at MP13 (19.53%) near south-west Lantau during the Phase 1 construction dry season of, at MP5, SC19 and MP13 (14.68%, 21.3% and 20.9% respectively) during the Phase 2 construction dry season and wet season (9.42%, 15.09% and 9.49% respectively) and at MT5, MP13 and SC19 (20.38%, 21.09% and 36.09% respectively) during the Phase 3 construction dry season and at SC19 (20.35%) in the wet season. Hydrodynamic and Water Quality Impacts Following Island Formation 9.3.17 The presence of an island could locally affect the flow current in the area. Tidal currents in this area are moderate, (depending on the phase tidal cycle). On the ebb tide, the flows accelerate around the southern tip of Lantau to pass by the Soko’s, (ERM 19992). The impacts on flow through the major channels, predicted due to the presence of the island, would be small, with the largest difference being a 4.03% increase of accumulated flow predicted at West Lamma Channel during the wet season. An increase in currents to the west and north of the island at 3.7% and 29.9% (on average) was also predicted. 9.3.18 In the water quality modelling, 16 sensitive receivers that are close to the site were selected for presentation. Of the 16 chosen indicator points, 5 are located in the Southern WCZ (MP5, FP4, SC19, MP12 and RD), 1 in the North Western Supplementary WCZ (MP13) and 10 in Mainland waters (WD2, MF2 to MF7 and MF10 to MF12). WD2 (Chinese White Dolphin Conservation Zone) and MFs (Fish/Scollop/Rockshore Culture Areas) are classified as Category 1 and 2 respectively in the Mainland Sea Water Standard.
2 ERM-Hong Kong Ltd (1999) Strategic Assessment and Site Selection Study for Contaminated Mud Disposal – Strategy Selection Report, Civil Engineering Department.
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9.3.19 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.34 to 6.75mg/L and were above the WQO of 4mg/L and 2mg/L respectively as well as the Mainland standard of 6mg/L (category 1) and 5mg/L (Category 2). Compared to the baseline water quality results, the presence of the island would reduce both 90%ile depth-averaged and bottom DO at MP5 (Potential Marine Park/ Marine Reserve near Fan Lau), FP4 (Finless Porpoise Area near Tung Wan, Lantau Island), MF7 and MF11 (Fish/Scallop/Rockshore Culture Areas near Aizhou Islands and Baili Island). The percentage decreases at these sensitive receivers were less than 2%. 9.3.20 The predicted average dry season salinity ranged from 32.75 to 34ppt. The differences in the dry season salinity levels caused by the presence of the island were minimal (less than 1%) at all the selected indicator points as compared to the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 9.3.21 The predicted dry season SS levels at the indicator points were in the range of 3.82 to 5.49mg/L. Compared to the baseline water quality results, the percentage differences in SS level caused by the presence of the island were less than 4%. Recognising the WQO requires that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 10mg/L (Category 1) and 100mg/L (Category 2), these differences are considered small. 9.3.22 The predicted dry season E.coli levels at all indicator point were 1count/100ml and were well below the WQO of 610cfu/100ml and the Mainland standard of 200count/100ml. No notable change in E.coli levels was observed at any of the indicator points. 9.3.23 The predicted average dry season UIA (0.00207 – 0.00344mg/L) at all indicator points were very small and well below the WQO of 0.021mg/L and the Mainland standard of 0.020mg/L. Both MP5 (Potential Marine Park/ Marine Reserve near Fan Lau) and FP4 (Finless Porpoise Area near Tung Wan, Lantau Island) show an increase in the UIA level of 11.06% and 5.08% respectively while no notable change or reductions were observed in the remaining receivers. 9.3.24 The predicted dry season TIN levels at the indicator points in Mainland waters ranged from 0.0935 to 0.109mg/L. The predicted levels were below the Mainland waters Standard of 0.2mg/L (Category 1) and 0.3mg/L (Category 2). Meanwhile in Hong Kong waters, MP5 (Potential Marine Park/ Marine Reserve near Fan Lau) and FP4 (Finless Porpoise Area near Tung Wan, Lantau Island) showed an increase in TIN level of 14.17% and 6.52% respectively. Since the Hong Kong WQO of TIN is an annual mean value, the predicted levels for the dry and wet seasons were averaged and compared with the WQO. The results are discussed below in Section 9.3.30. 9.3.25 According to the water quality modelling results for the wet season, the predicted 90%ile DO for depth average and bottom layer at the sensitive receivers in Hong Kong waters ranged from 4.62 to 5.38mg/L and the values were above the WQOs of 4mg/L and 2mg/L respectively. However, for the sensitive receivers in Mainland waters, most of the sensitive receivers breached the marine water standards. For WD2 (Chinese White Dolphin Conversation Zone), the depth-averaged and bottom layer DO of 4.97 and 4.8mg/L were below the Mainland water standards of 6mg/L for Category 1. The 90%ile DO levels at MF2 to MF6, (ranged between 4.5 to 5.0mg/L), breached the Mainland water standards of 5mg/L for Category 2. However, the DO baseline levels at these indicator points also breached the relevant standards. Compared to the baseline water quality results, the percentage differences for 90%ile depth-averaged and bottom DO at all indicator points were less than 4%. 9.3.26 The predicted average salinity in the wet season ranged from 11.40 to 26.50ppt. The percentage differences were within 5% and are below the WQO of 10%.
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9.3.27 The predicted wet season SS levels at all the indicator points were in the range of 4.36 to 10.07mg/L. Compared to the baseline water quality results, the percentage differences in SS level caused by the presence of the island were in the range of 0.1 to 8.15%. Recognising the WQO requirements that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 10mg/L (Category 1) and 100mg/L (Category 2), these differences are considered very small. 9.3.28 The predicted E.coli wet season concentrations at all indicator points were low and ranged from 1 to 8count/100mL which were well below the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100ml. 9.3.29 The predicted average wet season UIA (0.00338– 0.00498mg/L) at all indicator points were low and were well below the WQO of 0.021mg/L and the Mainland standard of 0.020mg/L. 9.3.30 For the predicted wet season TIN levels, the values ranged from 0.1852 to 0.5238mg/L. The wet season TIN levels at WD2 for both baseline scenario (0.516mg/L) and operational scenario (0.523mg/L) exceeded the Mainland standard for Category 1 of 0.2mg/L. The TIN levels at MF2 to MF6 in Mainland waters were in the range from 0.3557 to 0.4988mg/L which is above the Mainland standard for Category 2 of 0.3mg/L. It should be noted that the predicted TIN levels for the baseline scenario also exceeded the relevant Mainland Standards. Meanwhile, since the Hong Kong WQO of TIN is a yearly value, the predicted mean TIN levels at MP5, FP4, MP13, SC19, MP12 and RD for the dry and wet seasons were averaged to represent the annual mean values. Of the 6 indicator points, only MP13 was shown to comply with the WQO. The remaining 5 sensitive receivers, located in the Southern WCZ breached the WQO of 0.1mg/L with calculated annual mean values ranged from 0.229 to 0.242mg/L. The calculated averaged baseline concentrations at these stations also exceeded the WQO. Cumulative Impacts 9.3.31 There are no known proposed or committed marine developments currently planned within the area of the site. CED has advised that the South Cheung Chau Disposal Ground (which receives uncontaminated dredged muds) has little or no capacity remaining. It is assumed that mud-dumping activities at the Disposal Ground will have ceased by the time of construction.
Waste Management / Disposal Impacts 9.3.32 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points across the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 9.3.33 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 9.3.34 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 125Mcum • Volume of muds to be dredged for the outer sea wall: 8Mcum
9.3.35 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5.
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9.3.36 Waste delivery to the site will be by marine vessel which will have a lower GHG emission per kg waste handled, compared to the road transport given the fact that the capacity of a marine vessel is almost 100 times more than a truck. The cumulative distance between marine RTSs and the site is around 440km as estimated in the Preliminary Marine Review (March 2002). In view of these, the potential GHG impacts are considered to be moderate.
Ecology Baseline Conditions 9.3.37 Notwithstanding the previous sand extraction over a portion of the site area, there are a number of ecological resources of conservation interest in the vicinity of the potential SIL. 9.3.38 The site lies in an area known to contain fish spawning and nursery grounds. There are medium density sightings of the Chinese White Dolphin and Finless Porpoise as well as coral communities at the nearby Soko Islands. There are proposals to designate the adjacent Soko islands as a Marine Park. The site is one of six that has been short-listed for deployment of an artificial reef (AR) by AFCD, (ERM 1999a3). Figure 9.1 shows the locations of ecologically sensitive areas in the vicinity of the site. 9.3.39 Ecological surveys have been undertaken at the west and northern coast of the adjacent Soko Islands (Siu A Chau), under the Coastal Ecology Studies conducted by CED (BCL 1997 4 ) and as summarised in the Artificial Reef Deployment Study, (ERM 1999a). The surveys concluded that overall, the coral, fish and invertebrate communities at the Soko Islands (adjacent to the site) were low to moderate both in terms of species diversity and abundance. 9.3.40 Notwithstanding their low abundance and diversity, the occurrence of both hard and soft corals was considered to be notable. Corals generally exhibit a low tolerance to elevated sediments in the water column and distribution was previously thought to be restricted to the clearer waters east of Lamma Island, which are less affected by sediment loads of the Pearl River Estuary. It is not clearly understood why hard corals have been able to colonise in this area, however it is thought that the backwash from boats passing along the shipping channel immediately to the north may help to prevent sedimentation of corals in this location. 9.3.41 Benthic invertebrate surveys during 1976 and 1977 as part of a territory wide study (Shin and Thompson, 1982) identified that the south west waters, (including Soko Islands) dominated by polychaete communities (82.5%), with a high species diversity. More recent grab surveys within the site footprint of the proposed SIL, (at the edge of the former marine borrow area) confirmed the dominance of polychaete communities, and also recorded very high numbers of benthic macroinvertebrates. However, it was postulated that the marked increase in macroinvertebrates may have been due to a recruitment pulse immediately prior to sampling (ERM 1997a)5. 9.3.42 Cetacean surveys in Hong Kong waters, between 1995 and 2000, (Jefferson 1998 and 2000) indicate that the area is a habitat for the Chinese White Dolphin and Finless Porpoise The site does not fall within the critical habitat areas for either of these species, (see Figure 9.1). Frequency by Finless Porpoise is generally low, (their core habitat is further east toward South Lamma). However, Chinese White Dolphin can be abundant particularly during summer and autumn months6.
3 ERM-Hong Kong Ltd (1999a) Artificial Reef Deployment Study: Technical Paper 3 – Site Selection, Agriculture & Fisheries Department, Hong Kong Government.
4 Binnie Consultants Limited (1997) Coastal Ecology Studies: Soko Islands Qualitative Survey Final Report. Civil Engineering Department, Hong Kong Government.
5 ERM-Hong Kong Ltd (1997a) Seabed Ecology Studies: Soko Islands Final Report, Civil Engineering Department, Hong Kong Government.
6 http://www.afcd.gov.hk/con_new/cdp_distribution.htm
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9.3.43 The nearest sites designated for their conservation interest are the proposed Marine Parks at the Soko Islands and at South Lantau (which are approximately 1.5km to the west and 2km to the north respectively). 9.3.44 The key sensitive receivers during construction phase are ecological habitats near the site. Therefore the sediment plume impact from the site is likely to be significant. 9.3.45 The sheltered bays around Tong Fuk, (South Lantau) are a recognised habitat for Horseshoe Crab. Given the lack of disturbance to the existing South Lantau coastline west of Tong Fuk it is also likely these species are to be found in isolated undisturbed bays on south west Lantau, closer to the SIL, and possibly around the Soko Islands. Direct Habitat Loss 9.3.46 The site footprint covers an area of 475ha, and partially coincides with the former borrow area. No direct studies on the recolonisation of the former borrow are have been carried out, however, the site is comparatively ecological poor, and direct impacts are likely to be moderate. Loss of water column habitat and feeding ground is also likely to impact upon the Chinese White Dolphins / Finless Porpoise. Water Quality / Hydrodynamics 9.3.47 Ecologically important habitats at the Soko Islands and South Lantau are relatively close to the potential SIL and impacts on local flow regime and disturbance to the status quo may be significant. Fish and coral habitat may be adversely affected if sediment is transported / deposited around the Soko Islands and at the proposed Artificial Reef. 9.3.48 The results of numerical modelling do not indicate a significant decline in water quality associated with works for the SIL. Suspended solids concentrations at the coral community at north Siu A Wan (SC19) are predicted to increase by 1.5mg/L above baseline levels. However, the spread of the sediment plume may potentially be significant as levels of suspended solids as far west as the potential Southwest Lantau Marine Park / Reserve (MP13) and as far north as the potential Fan Lau Marine Reserve (MP5) are predicted to increase by an average of 1mg/L. Thus, the diversity and number of ecological receivers exposed to this marginal increase may be significant. 9.3.49 The model output does not indicate that there will be any significant operational change in hydrodynamics / water quality. Marine Vessel Disturbance 9.3.50 Increased vessel movements in the area will increase the likelihood of vessel disturbance of marine mammals. Whilst the area is not a core habitat for Chinese White Dolphin, sightings are moderate, and the incidence of vessel collision, particularly during summer and spring months is likely to be significant.
Fisheries 9.3.51 Baseline data on fisheries is available from Port Survey Data and data from the Consultancy Study, Fisheries Resources and Fishing Operations in Hong Kong waters (Fisheries Resources Survey, ERM 1998)7. 9.3.52 The site lies in an area identified as having significant spawning and nursery grounds as well as holding significant fish stocks. Trawl surveys to the north and east of the Soko Islands under the Fisheries Resources Survey yielded large fish catches compared to other areas of Hong Kong surveyed indicating a high value fishery area. The majority of the catch comprised mantis shrimp, which have a high commercial value.
7 ERM-Hong Kong Ltd (1998) Fisheries Resources and Fishing Operations in Hong Kong Waters, Agriculture & Fisheries Department, Hong Kong Government.
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9.3.53 A trawl survey conducted under the Fisheries Resources Survey reported the highest mean catch weight per month from sites in southern waters, particularly South Cheung Chau, South Lantau, and South Lamma. As noted in the C&D Materials Study, (Conceptual Layout Study Report, March 2002), the data collected under the Fisheries Resources Survey was from a single survey and the findings run contrary to the relative production estimates from the fisher and port surveys. This indicates that the area is potentially richer in resources than its current exploitation rate would imply. As the site footprint covers an area of 475ha, there would be a direct fisheries impact through the loss of spawning / nursery grounds. 9.3.54 There are no fish culture zones in HKSAR waters in the vicinity of the proposed SIL. Two sites, located to the immediate east and west of Tai A Chau (approximately 3km from the SIL) are reportedly being examined as a potential Fish Culture Zones, (ERM 1997b)8. As reported in the ‘Ecology’ sub-section above, the results of the modelling exercise for waters around the Soko Islands predict only a marginal increase in suspended solids levels of 1.0 - 1.5mg/L above baseline. There are five fish culture areas in Mainland waters to the south and southwest of the proposed SIL (MF2 – MF6). The predicted increase in suspended solids levels at these sites does not exceed 1mg/L above baseline conditions during construction, and there are no predicted increases in any modelled parameter during facility operation.
Cultural Heritage 9.3.55 There is no immediate evidence of archaeological remains in this area. However Siu A Chau and Tai A Chau land based archaeological sites are located on the nearby Soko Islands. Archaeological finds on these islands indicate occupation of the islands during prehistoric times and during the Tang Dynasty. This suggests that the coastal area of the Soko Islands has been used by seafaring people for several thousands of years. 9.3.56 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 9.3.57 Landscape Planning Designations – This area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 9.3.58 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 9.3.59 Landscape Character – The island landfill site falls within the Southern Coastal Waters LCA and partly within the South Lantau Waters LCA (Figure 9.4). The landscape of this part of the former is characterised by a generally expansive and open water, whilst that of the latter is a more sheltered coastal landscape characterised by the relationships of outlying islands and areas of sea between them. The coastal waters of South Lantau are extremely natural and undisturbed (Figure 9.3). Numerous islands are scattered along the coast, with the Sokos forming a coherent group. Key islands in this area include Lantau, the Soko Islands as well as islands in PRC territorial waters (Figure 9.4). 9.3.60 There exists potential for a large magnitude of impact on landscape character, resulting from construction works that will introduce new artificial elements which are incompatible with the existing mainly open and natural characteristics of the marine landscape. The predicted impact on landscape character during the construction/operation phase of the life cycle of the project will be substantial. During the afteruse phase, these impacts are likely to be reduced a little, as the completed island is restored and the landscape mitigation measures are fully implemented. As a consequence, the long-term impact on landscape character will be moderate/substantial.
8 ERM-Hong Kong Ltd (1997b) Site Search for a New Power Station: Preliminary Site Search (Revised Final Technical Report No. 2), Hongkong Electric Company, Ltd.
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9.3.61 VSRs – VSRs affected by the proposals are identified in Tables 9.3 and 9.4. The extent of the project visual envelopes is shown in Figure 9.5 and the key views to the proposed island landfill are shown in Figure 9.6. Recreational VSRs, such as Chinese White Dolphin watchers, boating, fishing, diving, water sports activities and visitors to Fan Lau Fort near Lantau Trail, will be most affected by the proposed islands as they are possibly the closest VSRs. Other recreational VSRs affected will be those at Lantau Peak (Fung Wong Shan) Trail, Tai Long Wan Beach, Tian Tan Buddha Status and Pui O Wan Beach. 9.3.62 Because of the location of the island there are no large areas of population within the primary visual envelope. Key residential VSRs in the area include mainly the population of Tai Long Wan Village (Shek Pik). Institutional VSRs will be affected at Chung Hau Prison and the Sha Tsui Detention Centre in Chung Hau. Other VSRs, such as travellers on vessels using the fairways and shipping lanes as well as the South Lantau Road, are often transient and so resulting visual impacts are less. 9.3.63 All VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as relatively close artificial elements contrasting with the coherent natural qualities of the existing landscape. Resulting impacts during construction/operation period will be moderate to substantial. After the restoration of the landfill island, its visual impact will be reduced and the overall residual visual impacts on major VSRs during the afteruse phase will be slight to moderate. 9.3.64 Mitigation Measures – Landscape and visual mitigation measures are outlined in Section A of the Report and illustrated in Figure 9.8.
Landfill Gas 9.3.65 There are no sensitive receivers (targets) or pathways within 500m of the site. Therefore, there are no potential off-site landfill gas hazards. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 9.3.66 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source. 9.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 9.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are those which are site-specific.
Air Quality 9.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice.
Noise 9.4.3 No specific noise mitigation measures are recommended at this stage, other that good site practice.
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Water Quality 9.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the artificial island reclamation. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in any EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Solid Waste 9.4.5 As an artificial island site, application of a floating boom curtain to control the dispersal of litter within public fill. Ecology 9.4.6 No specific measures to protect areas of ecological value are recommended at this stage. The application of measures to prevent unacceptable impacts on water quality will also apply to ecological resources, and are likely to be necessary. Given the sensitivity and close proximity of adjacent ecological resources, the likely effectiveness of any mitigation measures would need to be carefully evaluated. 9.4.7 It is envisaged that given adequate edge protection design, assemblages typical of those adapted to hard substrates would colonise the rubble mound sea wall of the artificial island. Ecological enhancement through construction of an artificial reef, would be appropriate, at SIL, as the site has been identified as a potential site for an AR under the AFCD Study9. Fisheries 9.4.8 Mitigation applied for the protection of ecological resources would apply equally to the protection of fisheries resources.
Cultural Heritage 9.4.9 No specific measures for the protection of cultural heritage are deemed necessary at this stage. This should be re-evaluated in the event that a marine archaeological assessment is carried out as part of an EIA if this site is investigated further.
Landscape & Visual 9.4.10 Landscape and visual mitigation measures are identified in Part A of the Report.
9 ERM-Hong Kong Ltd (1998). Artificial Reef Deployment Study, Final Report.
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9.5 Summary 9.5.1 A summary of the SEA for the SIL is provided in Tables 9.1 and 9.2:
Table 9.1: Soko Islands Landfill SEA
Impacts Score Commentary
Air Quality Assessment 1 Distance to areas of air O There are no ASRs within 500m of the site. sensitive land use 2 Presence of topographic O There are no features which would affect air dispersal. In features which could addition as there are no ASRs within 3km, this criterion is not decrease or exacerbate applicable. impacts 3 Occurrence of O The predominant wind direction is towards ASRs. However the meteorological conditions remoteness of ASRs is such that this criterion is not which could exacerbate applicable. impacts 4 Cumulative Impacts of O Review of all known planning information (OZPs and the relevant emissions (TSP SWNT Development Strategy Review) indicate there are no (construction), NOx, CO, other confirmed or planned developments within 3km of this SO2 – LFG Flare) taking marine site, which could contribute to cumulative air quality into account ambient impacts. conditions 5 Total Emissions of Air - Waste will be delivered to the site by marine vessel and the Pollutants from the cumulative distance to be travelled is estimated to be 440km. territory-wide waste transportation between the RTSs and the Site 6 Overall Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment 1 Distance to areas of noise O There are no NSRs within 300m of the site. sensitive land use 2 Topographic Features O The area between the proposed landfill site and the nearest land mass Soko Islands is marine (flat). Notwithstanding, as (only applicable if there there are no NSRs within 3km this criterion is not directly are NSRs within 300m) applicable. 3 Cumulative Impacts of O No developments that could cause cumulative impacts. developments within 300m 4 Overall Impact O ‘Neutral’. Negligible noise impacts on surrounding NSRs due to its remote siting.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O As a marine site, no water-course diversions are required. 2 Potential for sediment O The site is a partially within the Soko Islands marine Borrow contaminant release Area. EPD routine monitoring data indicates the potential for impacts associated with contaminated muds is limited.
3 Potential impacts on - Exceedance of the WQO for SS is predicted in one location, WSRs SC19 (to the north of the Soko Islands) during construction. It is predicted that both DO and TIN standards in the operational phase would be breached, however, these were both breached in the baseline scenario and the elevations due to the presence of island were not significant, therefore, the island would not be the cause of the exceedances. 4 Potential Impacts on O This is a marine site - there are no groundwater issues. Groundwater 5 Potential Cumulative O No major marine developments currently planned around the Impacts (Potential for site. concurrent projects to
exacerbate preceding impacts) 6 Overall Impact - Potential water quality impacts are considered to be ‘Negative – Low’. There are a limited number of WSRs in the area; Soko Islands in close proximity may experience significant SS levels during construction of the artificial island.
Waste Management Assessment 1 Balance of Materials + The site could accommodate a major volume of public fill (surplus/deficit of public fill (125Mcum) negating the need to import filling material for site needed for landfill formation. Dredged muds will be incorporated with the fill development) materials within the island footprint. 2 GHG emissions from - Waste will be delivered to the site via marine vessel. The mode of transport for distance travelled from marine RTS(s) to the site has been delivery of waste to the estimated to be 440km. site from RTSs 3 Overall Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance out of the benefit for being able to accommodate C&D surplus materials and the relatively larger amount of GHG emissions for the longer distance travelled.
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary _ The model output indicates that sediment plume from the environmental impacts on Works may affect most likely in a limited manner the waters “Areas of Absolute around the potential Marine Parks / Reserves at Soko Islands, Exclusion” Southwest Lantau and South Lantau (Fan Lau). 2 Affects an important - - Benthic habitats previously disturbed, not considered of major habitat importance. Coral at Soko Islands susceptible to sedimentation impacts. Loss of habitat for fish (feeding habitat for Chinese White Dolphin) and potential disturbance of habitat for Horseshoe Crab S Lantau. 3 Affects species of - /- - This site may disturb an area of moderate density sighting of conservation importance Chinese White Dolphin and coral habitat off north Siu A Chau. 4 Potential for Cumulative O No major marine developments currently planned around the Ecological Impacts on site. sites of recognised value 5 Overall Impact - / - - Ecological impacts are considered to be ‘Negative – Low / High’ due to the close proximity to two proposed Marine Parks as well as the potential impacts upon species of conservation interest.
Fisheries Assessment 1 Potential for secondary - There is some potential for slight increases in suspended environmental impacts on solids levels on a number of Mainland FCZ to the south. The “Areas of Absolute potential Marine Parks at Soko Islands, Southwest Lantau and Exclusion” South Lantau (Fan Lau) may also experience marginal increases in suspended solids levels. 2 Affects important - - This site is within a known spawning ground of a productive mariculture/ fisheries fishing area. Whilst predicted increases in suspended solids resources (including are low, there would be direct habitat loss. spawning / nursery ground) 3 Potential for Cumulative O No major developments planned within 5km of the site. Fisheries Impacts on sites of recognised value 4 Overall Fisheries Impact - / - - The potential fishery impacts are considered to be ‘Negative – Low / High’, due to the potential direct impact on fisheries and spawning grounds, as well as indirect impacts on nursery function of beaches on S. Lantau.
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Impacts Score Commentary
Cultural Heritage Assessment 1 Important cultural O There are no known sites of cultural heritage significance. (Declared, Deemed or Graded Sites) / archaeological sites 2 Potential for - There is evidence of land based archaeological finds nearby archaeological value on the adjacent Soko Islands, suggesting that the coastal area of the Soko Islands has been used by seafaring people for several thousands of years. Recognising the lack of archaeological data currently available, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land based, (on Heritage Impacts on sites the Soko Islands (1.5km), therefore they would not be affected of recognised value by this development. There are no planned or confirmed projects, which may cause cumulative heritage impacts. 4 Overall Impact - The potential impacts on cultural heritage are considered to be ‘Negative – Low’. Whilst there is not direct evidence of cultural heritage remains in the site area, the occurrence of remains on nearby Soko Islands increases the potential for marine archaeological finds.
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of landscape is not covered by any planning Planning and Designations designations reflecting landscape/landscape values and so there will be no impact on these values. Overall impacts will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no significant Resources impacts on landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - - The proposed SIL is incompatible with the open, isolated and Character natural qualities of this area of sea and coast and resulting impacts on landscape character will be Negative – High. 4 Visual Impact - / - - The numbers of VSRs affected by the proposal is comparatively small. The most affected VSRs are a limited number residents in Tai Long Wan Village and visitors who use that part of the sea area for active and passive recreation and the impact on them is substantial to moderate. Generally, visual impacts will be Negative – Low/High.
5 Overall Impact - / - - Overall, landscape and visual impacts will be ‘Negative – Low / High’ for the following reasons:
• There are no landscape designations covering the disposal site;
• No significant landscape resources are affected;
• The open, natural and isolated landscape character of the Southern Coastal Waters will be significantly compromised;
• There are very low numbers of residential VSRs within the visual envelope of the Site and an extremely small number close to it.
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Impacts Score Commentary
Landfill Gas Assessment 1 Distance between the new O This is a marine site located over 1.5km west of Soko Islands / extended landfill and SRs which are uninhabited. The nearest sensitive receivers are >250m away 2 Number of Receivers O There are no sensitive receivers within 250m of the site. within 250m (i.e. Consultation Zone) 3 Man-made / Natural O None Pathways for LFG Migration 4 Additional Utilisation of O LFG would be utilised on-site. There are no potential off-site LFG to Reduce GHG users of LFG. Emissions 5 Overall Impact O ‘Neutral’
Table 9.2: Summary of Soko Islands Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact - / - - Negative – Low / High Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - / - - Negative – Low /High Overall Landfill Gas Impact O Neutral
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Table 9.3 Assessment of Significance of Visual Impacts for Soko Islands Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted) Identity Key Visually Sensitive Approx Minimum Nos. of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Construction / High) before Mitigation (Insubstantial, and Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR42 Tai Long Wan Village (Shek 5km Very Few Intermediate High Moderate to Moderate Pik) Substantial Institutional VSRs VR43 Chung Hau Prison and Sha 5.5km Few Intermediate Low Slight to Moderate Slight to Moderate Tsui Detention Centre Recreational VSRs VR44 Tai Long Wan Beach 5km Few Intermediate Medium Moderate Moderate to Slight VR45 Tian Tan Buddha Statue (Po 9km Many Intermediate Medium Moderate Moderate Lin Monastery) VR20 Lantau Peak (Fung Wong 11km Very Few Intermediate Medium Moderate Moderate Shan) VR46 Pui O Wan Beach 13km Few Small Medium Moderate to Slight Slight VR11 Area for Chinese White 0km - 13km Few Large Medium Substantial to Substantial to Dolphin Watching, Boating, (varies) Moderate Moderate Fishing and Diving activities VR47 Near Lantau Trail at Fan Lau 2km Few Large Medium Substantial to Substantial to Fort, Fan Lau Moderate Moderate Travelling VSRs VR48 South Lantau Road (Shek Pik 5km Many Small Low Slight Insubstantial Reservoir) VR49 On Vessels using the Fairways 1km Many Intermediate Low Slight to Moderate Slight to Moderate and Shipping Lanes
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Table 9.4 Assessment of Significance of Visual Impacts for Soko Islands Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted) Identity Key Visually Sensitive Approx Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Afteruse High) before Mitigation (Insubstantial, and Source(s) Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR42 Tai Long Wan Village (Shek 5km Very Few Intermediate High Moderate to Moderate Pik) Substantial Institutional VSRs VR43 Chung Hau Prison and Sha 5.5km Few Intermediate Low Slight to Moderate Slight Tsui Detention Centre Recreational VSRs VR44 Tai Long Wan Beach 5km Few Intermediate Medium Moderate Slight VR45 Tian Tan Buddha Statue (Po 9km Many Intermediate Medium Moderate Slight Lin Monastery) VR20 Lantau Peak (Fung Wong 11km Very Few Intermediate Medium Moderate Slight Shan) VR46 Pui O Wan Beach 13km Few Small Medium Slight Insubstantial VR11 Area for Chinese White 0km - 13km Few Large Medium Substantial to Moderate Dolphin Watching, Boating, (varies) Moderate Fishing and Diving activities VR 47 Near Lantau Trail at Fan Lau 2km Few Large Medium Substantial to Moderate Fort, Fan Lau Moderate Travelling VSRs VR48 South Lantau Road (Shek Pik 5km Many Small Low Slight Insubstantial Reservoir) VR49 On Vessels using the Fairways 1km Many Intermediate Low Slight to Moderate Slight and Shipping Lanes
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10. SOUTH CHEUNG CHAU ISLAND LANDFILL 10.1 Basic Information Project Title 10.1.1 South Cheung Chau Island Landfill Site (SCCIL) – marine site M.5. Nature of Project 10.1.2 The Project would form a new marine based waste disposal site situated on the existing disposal ground for uncontaminated dredged mud situated south of Cheung Chau (see Figure 10.1). 10.1.3 The SCCIL would require construction of an artificial island of approximately 850ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. 10.1.4 Construction works would be as described in Part A, Section 3.2. In addition works for SCCIL would include: - Dredging of 20Mcum of underlying muds for seawall construction.
Location and Scale of Project 10.1.5 The SCCIL is located approximately 5km south of the western end of Lantau and 3km south of Cheung Chau. The island of Shek Kwu Chau lies 2.5km to the north west. The site coincides with the area used for mud disposal. Seabed levels in this area vary from 10 to 20m below Chart Datum. This site is bound by the SAR boundary to the south and a major shipping channel to the north. 10.1.6 The SCCIL would cover an area of 850ha to an elevation of +6 mPD. The artificial island would accommodate a landfill with a capacity of 140Mcum to an elevation of +56mPD. The SCCIL would accommodate approximately 225Mcum of fill material.
History of Site 10.1.7 The original mud disposal ground was gazetted in 1982, with further extensions in 1988 and in the early 1990s (1992-93). No formal EIA was carried out in relation to either of these series of extensions. This area was filled extensively with uncontaminated mud throughout the mid-1990s from the PADS and other projects. It is understood from CED that this Disposal Ground has little, if any, remaining capacity to accept further disposal. It is thus most unlikely that the disposal ground would operate during the construction of the island.
Number and Types of Designated Projects Covered 10.1.8 The SCCIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1.
10.2 Outline of Planning and Implementation Programme 10.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 10.2. Assuming landfill operations start in 2019, SCCIL would be full during the period 2035 to 2045, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 10.2.2 The proposed site is currently not covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the proposed site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. There are no future major committed developments on South Cheung Chau or Shek Kwu Chau (according to Layout Plans (L/I-CCE/2 and L/I-CCC/2A).
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10.2.3 This site falls within the boundary of the study area of the South West New Territories Development Strategic Review (SWNTDSR). The SWNTDSR identified the coastal waters off south west Lantau, Soko Islands and South Lamma as potential Marine Parks. The planning intention of the Marine Park is to protect and conserve the relatively unspoilt marine environment, and provide recreational and educational opportunities to the public in areas, as appropriate. 10.2.4 The SCCIL coincides with one of the sites proposed for development under the C&D Materials Study. 10.3 Possible Impacts on the Environment 10.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of SCCIL are outlined below. Figure 10.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 10.1 and 10.2.
Air Quality 10.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation (following reclamation). • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
10.3.3 No air sensitive receivers have been identified within 500m of the site, The nearest ASRs are on Shek Kwu Chau (approximately 3km to the nearest) and on Cheung Chau (approximately 4km). Significant air quality impacts are not anticipated. However, potential operational phase air quality impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other landuses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. Afteruse issues are not considered further in the SEA. 10.3.4 Marine vessel will be the mode of transportation for waste delivery to the site. The amount of air pollutants resulting from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 290km. As such, no impacts are anticipated.
Noise 10.3.5 The reclamation and landfill development has the potential to cause the following noise impacts:
• construction – from dredging, tipping, piling works and general construction activities; • operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
10.3.6 No noise sensitive receivers have been identified within 300m of the site, The nearest NSRs are on Shek Kwu Chau (approximately 3km to the nearest site boundary) and on Cheung Chau (approximately 4km). Significant noise impacts are not anticipated. However, potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other landuses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations.
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10.3.7 Whilst it is not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an off-shore reclamation site with no noise sensitive receivers in the vicinity, the more stringent requirements for noise emissions during the evening and night time periods are not expected to be an issue for this site. 10.3.8 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 10.3.9 The site is located within the Southern Water Control Zone (WCZ). The current through this area mainly flows in an east/west and west/east direction. Background water quality conditions have been established from EPD routine monitoring stations, the latest available data being that collected in 2000, (EPD 20011). The site is situated in the western waters of Hong Kong which are characterised by slightly elevated levels of suspended solids, (compared to Eastern Waters) as a result of the influence of the Pearl River Estuary. Locations of water quality monitoring stations are presented in Figure 10.1. 10.3.10 The South Cheung Chau Disposal Ground was used by the Airport Authority for the disposal of dredged mud from the airport platform development from 1992 to 1994. 10.3.11 The nearest regular EPD sediment monitoring station in this area is SS3, which lies approximately 5km to the east. Sediments at SS3 are considered to be uncontaminated according to the latest published data (EPD 2001). The South Cheung Chau Disposal Ground accepts uncontaminated marine muds. The potential for impacts associated with contaminated muds is considered limited. Key Issues and Sensitive Receivers 10.3.12 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
10.3.13 Sediment plumes may have some influence on beaches on south Lantau and Cheung Chau. However, these sensitive receivers are not along the main flow path and modelling findings indicate that the impacts will be minor (up to 15.2%) and that the WQO will not be exceeded. 10.3.14 The area south of Cheung Chau has no other WSRs within 1,000m, the nearest beach is on eastern side of Cheung Chau – Kwan Yam Wan which is over 4.5km away. Other beaches on Cheung Chau include Tung Wan (4.8km) and Tai Kwai Wan (5.2km). There are also 4 gazetted beaches on south Lantau all of which are at a distance of over 8km and not within the main flow channels. Reclamation and Site Formation 10.3.15 Due to the exposed location of the site, localised dredging is likely to be necessary for the seawalls prior to construction of the reclamation. However, the dredged material can be placed within the existing dumping grounds (within the footprint of the reclamation) reducing transport and spillage losses.
1 EPD (2001) Marine Water Quality in Hong Kong (in 2000). Environmental Protection Department, Hong Kong Government.
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10.3.16 Dredging would have to be monitored and controlled through dredging management. This area has been subject to sediment disposal since 1982 and was subject to extremely high disposal rates in the early 1990s (e.g. over 80Mcum in 1992). Thus whilst the levels of suspended solids in this area will rise as a result of the works, they are not anticipated to reach the levels experienced during dumping operations. 10.3.17 The hydrodynamic and water quality modelling predicts that the increase in SS level due to construction may exceed the WQO (30%) at NS3 (south-west of Cheung Chau) during both the dry (31.25%) and wet (30.77%) season for Phase 1 construction. Whilst not exceeding WQO, increases were predicted during Phase 1 construction at SC19 (10.78%), MP12 (16.97%) and RD (19.80%) in the vicinity of the Soko Islands and FP7 (15.09%) to the south west of Shek Kwu Chau, during the dry season. Increases were also predicted at these locations (13.28%, 17.22%, 16.28% and 14.83% respectively) during the Phase 2 construction dry season and at NS1 (9.09%) to the south of Cheung Chau during the Phase 2 construction wet season, and at FP7 (14.32%) (in the dry season) and NS1 (11.53%) (in the wet season) during the Phase 3 construction. Furthermore, it is most unlikely that the South Cheung Chau Disposal Ground would operate during the construction of the island, and so cumulative compacts would not arise. Hydrodynamic and Water Quality Impacts Following Island Formation 10.3.18 The presence of the island would cause only slight changes in momentary flow in the major channels. Accumulated flows through the West Lamma Channel were predicted to increase by 7.92% and 7.45% during the dry and wet seasons respectively, whilst an increase of 9.84% was predicted during the wet season for the Tathong Channel. The presence of the artificial island was not predicted to have a significant effect on the current velocity field during either the wet or dry season. It was however predicted that the proposed island would cause significant change to the current velocity with average percentage increases of 16.54% and 19.70% being predicted to the northeast and northwest respectively. 10.3.19 In the hydrodynamic and water quality modelling, the relative differences in tidal flux between major channels, including Victoria Harbour, East and West Lamma Channels and Adamasta Channel, were investigated. It is predicted that the presence of the island would cause a small reduction in the accumulated fluxes during the wet season neap ebb and neap flood periods in both Victoria Harbour (-1.44% and -0.91% respectively) and East Lamma Channel (-0.52% and -1.34% respectively) and small increases in the remaining tidal phases. The increment ranged from 0.00% to + 0.41% for Victoria Harbour and from +0.05% to +1.17% for East Lamma Channel. 10.3.20 It is also predicted that the island would cause minimal impact on the tidal fluxes during the dry season (changes of 0.00% were predicted by the model) to West Lamma Channel. There would be small increases (ranged from +0.58% to +2.53%) in accumulated fluxes during the wet season for all tidal phases except only for spring flood period where a small reduction (- 3.77%) in the accumulated fluxes was predicted by the model. 10.3.21 The effect on the Adamasta Channel is predicted to be minimal during the dry season (changes of 0.00% were predicted by the model. The effect however would be quite large during the wet season. There would be a large reduction in the calculated fluxes during the wet season spring ebb and neap ebb periods (-24.40% and -63.64%) respectively. During the wet season spring flood and neap flood periods, the effects were predicted to be relatively smaller (+11.6% and 0.94% respectively). 10.3.22 The overall changes in flow discharges through these four channels would however be small. The net reductions would be within 0.1%. This relatively small change in flow indicated that the dispersion capability of harbour west area would not be changed by the presence of the artificial island on this site. However, the flow would be redistributed from the Adamasta Channel to the other channels and the West Lamma Channel would receive the least share of redistribution.
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10.3.23 In the Water Quality and Hydrodynamic Modelling, 27 sensitive receivers that are close to the site were selected for presentation. Of the 27 chosen indicator points, 22 are located in the southern WCZ (CW4, GB11-13, HC1, GB3, FP7, FP1-3, 8, MP6, 12, SC19, 20, RD, NS1-4 and NS10-11) and the remaining 5 are all located in Mainland waters (MF5-9). All MFs are classified as Category 2 in the Mainland Sea Water Standard. 10.3.24 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.31 to 7.45mg/L and was above the WQO of ≥4mg/L for depth-average and ≥2mg/L for bottom DO as well as the Mainland Standard of 5mg/L. The predicted average salinity ranged from 33.70 to 34.00ppt. Compared to the baseline water quality results, the percentage differences in salinity and DO levels caused by the presence of the island were insignificant (less than 2%) at the selected indicator points. For salinity, the difference was well below the WQO which states that any change due to any waste discharge should not exceed 10% of natural ambient level. 10.3.25 The predicted SS levels for the dry season at the indicator points were in the range of 3.83 to 5.22mg/L. It is predicted that the island would not cause significant impacts to the SS levels in the vicinity. The greatest increase in SS level was observed in NS11 (Fishery Nursery/Spawning Ground South of Lantau Island) with 6.86%. The percentage difference of all of the selected indicator points were below the WQO that states that change due to waste discharge should not raise the natural ambient level by more than 30% as well as the Mainland standard that man-made increment shall not exceed 100mg/L. 10.3.26 For E.coli, the predicted dry season levels were in the range of 1 to 82count/100mL which were well below the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. The highest deviations from the baseline scenario were observed at indicator point MP12 (Potential Marine Park/Marine Reserve & Fishery Nursery/Spawning Ground near Soko Island) with a 100% or 1count/100mL increase of E.coli levels and HC1 (Horseshoe Crab Area near Tong Fuk) with a 48.28% or 14count/100mL reduction of E.coli levels. The baseline and operational phase scenarios for the remaining indicator points were similar. 10.3.27 The predicted average dry season UIA (0.00067 – 0.00350mg/L) at all indicator points were very small and well below the WQO of 0.021mg/L and the Mainland standard of 0.02mg/L. NS11 (Fishery Nursery/Spawning Ground South of Lantau Island) and GB11 (Gazetted Beaches in Cheung Chau) showed a large reduction in UIA level with differences of 14.75% or 0.00032mg/L and 14.96% or 0.00035mg/L respectively. 10.3.28 The predicted dry season TIN levels (0.0862 – 0.0975) at the indicator points in Mainland waters (MF5-9) were very small and well below the Mainland standard of 0.3mg/L. Since the Hong Kong WQO of TIN is an annual mean value, the predicted mean TIN levels at the indicator points in Hong Kong waters for the dry and wet seasons were averaged to represent the annual mean values. All 22 indicator points breached the WQO of 0.1mg/L with calculated annual mean values ranging from 0.1455 to 0.2549mg/L. However, The calculated average baseline concentrations at these stations also exceeded the WQO. 10.3.29 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer at the indicator points in Hong Kong waters ranged from 4.64 to 6.73mg/L, with the values were well above the WQOs of ≥4mg/L for depth-averaged and ≥2mg/L for Bottom DO. Meanwhile, for sensitive receivers in Mainland waters, MF5 and MF6 (Fish/Scallop/Rockshore Culture Areas near Zhizhou Islands) breached the WQO of 5mg/L for 90%ile DO for the bottom layer. However, the DO baseline levels at these 2 indicator points also breached the relevant standards. 10.3.30 The predicted average salinity in the wet season ranged from 16.50 to 25.10ppt. Compared to the baseline water quality results, the percentage differences in salinity caused by the presence of the island were in the range of 1.00 to 7.30%. The presence of the island would cause reduction in the salinity at all indicator points except MF9 where no notable changes were observed. The percentage difference is below the WQO that states that change due to any waste discharge should not exceed 10% of natural ambient level.
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10.3.31 The predicted average SS levels in the wet season at the indicator points were in the range of 4.49 to 7.79mg/L. In comparison to the baseline, the predicted percentage differences complied very well with the WQO that states that waste discharge should not to raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 10mg/L. 10.3.32 The predicted E.coli levels in the wet season were in the range from 1 to 9count/100mL which complied very well with the WQO of 610count/100ml and the Mainland standard of 200count/100mL. 10.3.33 The predicted average wet season UIA (0.00450 – 0.00553mg/L) at all indicator points were low and were well below the WQO of 0.021mg/L as well as the Mainland standard of 0.020mg/L. NS3 (Fishery Nursery/Spawning Ground Southwest of Cheung Chau) showed the largest reduction in UIA level with 10.83% or 0.00052mg/L. 10.3.34 The predicted wet season TIN levels (0.2241 – 0.4111mg/L) at the indicator points in Mainland were quite high. Both MF5 and MF6 (Fish/Scallop/Rockshore Culture Areas near Zhizhou Islands) breached the Mainland standard of 0.3mg/L. However, the predicted TIN levels for the baseline scenario in these 2 stations also exceeded the corresponding Mainland standard. Meanwhile, the predicted TIN levels (0.2737 – 0.4231mg/L) at the indicator points in Hong Kong waters were relatively higher as compared to the dry season data. All stations in Hong Kong waters breached the WQO of 0.1mg/L as discussed in Section 10.3.28 above. Cumulative Impacts 10.3.35 There are no major marine developments currently planned within the area of the proposed SCCIL, however, the possible breakwater in the West Lamma Channel could cause cumulative water quality and hydrodynamic impacts. This issue requires further investigation once the status of the breakwater is ascertained.
Waste Management / Disposal Impacts 10.3.36 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 10.3.37 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 10.3.38 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 225Mcum • Volume of muds be dredged for outer sea wall: 20Mcum
10.3.39 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 10.3.40 Regarding the GHG emissions, waste delivery to the site will be by marine vessel which will have a lower GHG emission per kg waste handled compared to road transport given the capacity is almost 100 times larger for a marine vessel than a truck. The cumulative distance between marine RTSs and the site is around 290km (Preliminary Marine Review (March 2002)). The GHG impacts are considered to be neutral.
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Ecology Baseline Conditions 10.3.41 This SCCIL coincides with the footprint for the South Cheung Chau Disposal Ground. This area has been subject to significant disturbance over a number of years from filling with dredged muds. Over 10m of marine mud has been dumped in this area over the last 17 years. 10.3.42 Figure 10.1 shows the locations of ecologically sensitive areas potentially affected by the project. 10.3.43 Several benthic invertebrate surveys have been undertaken at the Disposal Ground (Binnie Consultants Ltd 19942, ERM 19973, SAIC & Binnie 19944, Binnie Consultants Ltd 1995a5 and 1995b6). The only surveys conducted prior to gazettal of the site as a dumping ground were during 1976 and 1977 as part of a territory wide study (Shin and Thompson, 19827). 10.3.44 The benthic survey data collected in 1976/77 by Shin and Thompson (Ibid) indicates that prior to dumping, the sea bed showed a diverse community of polychaetes supported by a physical habitat characterised by a southeast-northwest gradient of sand/silt content. During dumping, grab surveys indicated that polychaetes still dominate the area, however, along with a change in physical habitat, the polychaete community became more dominated by opportunistic species such as the spionids which are often found in disturbed areas. ROV and dive surveys conducted since dumping began, indicate that within the dumping ground, consolidated mud sites support the highest abundance and diversity of epi-benthic invertebrate and fish communities. Whip corals were among those able to colonise the consolidated shell/mud/debris areas. 10.3.45 The survey data collected prior and since dumping has been carried out indicates that within the disposal ground, the polychaete community is less diverse than prior to dumping (and compared to reference sites), and is dominated by more opportunistic species. Above the mud, significant communities exist particularly where the mud has had sufficient time and opportunity to consolidate to form a reasonable habitat base. Records of hard corals on exposed rock pieces shows the potential of the area should hard substrate become available.
2 Binnie Consultants Limited (1994) South Cheung Chau and Sulphur Channel, Seabed Ecology Pilot Survey by Grab Sample, Draft Report. Report to Civil Engineering Department, Geotechnical Engineering Office.
3 ERM-Hong Kong Ltd (1997) Seabed Ecology Studies: Composite Report. Report to Geotechnical Engineering Office, Civil Engineering Department.
4 SAIC & Binnie (1994) REMOTS Survey of Soft-bottom Environments in Coastal Waters of Hong Kong: Demonstration of Rapid Bottom Mapping Technique. Report to Geotechnical Engineering Office, Hong Kong Government.
5 Binnie Consultants Limited (1995a) Working Paper on Benthic Recolonization in Relation to Dredging and Disposal Activities in Hong Kong Coastal Waters. Report to Civil Engineering Department, Geotechnical Engineering Office.
6 Binnie Consultants Limited (1995b) Underwater Dive Surveys of Hong Kong Waters. Report to Civil Engineering Department, Geotechnical Engineering Office.
7 Shin PKS and Thompson GB (1982) Spatial Distribution of the Infaunal Benthos of Hong Kong. Mar Ecol Prog Ser 10: 37-47.
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10.3.46 As a result of previous activities, the site is considered relatively ecologically poor when compared to areas of undisturbed seabed. In addition, the waters have consistently contained higher levels of suspended solids than other areas not subject to similar influences and elevated levels of suspended solids are likely to be “normal” for this site and the associated marine resources. 10.3.47 The key sensitive receivers during construction phase are ecological habitats near Soko Islands. Since there is some distance between the proposed site and Soko Islands, the sediment plume impact is likely to be moderate. 10.3.48 Cetacean surveys in Hong Kong waters, between 1995 and 2000, (Jefferson 19988 and 20009) during the period of mud dumping indicate that there is no significant presence of Chinese White Dolphin or Finless Porpoise within the site area. (see Figure 10.1). 10.3.49 The nearest protected areas are the proposed Soko Islands and South Lantau Marine Parks (which are 7.2km and 10.3km distant respectively) to the west. In addition, the proposed South Lamma Marine Park is 9km to the east. 10.3.50 Additional field surveys have been proposed for this site under C&D Materials Study (Agreement CE 46/2000), and should be taken in to account should this site be investigated further as part of an EIA. Direct Habitat Loss 10.3.51 The SCCIL covers an area of 850ha, and coincides with the disposal ground. Whilst some recolonisation of the seabed has occurred, the site is comparatively ecological poor, and direct impacts are likely to be moderate. Water Quality / Hydrodynamics 10.3.52 As described in the Section on Water Quality, the waters have consistently contained higher levels of suspended solids than other areas not subject to similar influences and elevated levels of suspended solids are likely to be “normal” for this site and the associated marine resources. Protected areas at Soko Islands, South Lantau and Lamma are relatively remote from this area and impacts are likely to be mitigable. There are no major marine developments currently planned in the vicinity of the site, however the possible breakwater in the West Lamma Channel could cause cumulative ecological impacts. This issue requires further investigation once the status of the breakwater is ascertained. Marine Vessel Disturbance 10.3.53 Current levels of mud dumping may discourage the presence of cetaceans within the disposal ground area. Further disturbance as a result of reclamation to form an artificial island for subsequent landfill development, is unlikely to exacerbate the situation.
8 Jefferson TA (1998) Population Biology of the Indo-Pacific Hump-Backed Dolphin (Sousa chinensis Osbeck, 1765) in Hong Kong Waters: Final Report. Final Report to Agriculture and Fisheries Department, HKSAR.
9 Jefferson TA (2000) Conservation Biology of the Finless Porpoise (Neophocaena phocaenoides) in Hong Kong Waters: Final Report. Final Report to the Agriculture, Fisheries and Conservation Department, HKSAR.
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Fisheries 10.3.54 Baseline data on fisheries is available from Port Survey Data and data from the Consultancy Study, Fisheries Resources and Fishing Operations in Hong Kong waters (Fisheries Resources Survey, ERM 199810). Due to the historical mud dumping activities, neither of these studies examined the fisheries resources directly within the area of the proposed site. A baseline survey of the disposal ground has been commissioned under the C&D Materials Study. 10.3.55 The SCCIL site lies within two fishing areas; Cheung Chau (Area 30) and Shek Kwu Chau (Area 31). Port Survey Data from 1996/97 (AFD 1998) shows the total production per hectare of Area 30 is reasonable, whilst Area 31 is low. Of a total 210 fishing areas in Hong Kong, Area 30 and Area 31 ranked 36 and 118 respectively in terms of production per hectare. 10.3.56 The Areas support significant fishing effort, with up to 34% of Hong Kong's larger fishing vessel fleet (>15m) using these waters and up to 11% of Hong Kong's smaller vessels fishing in the area, (Scott Wilson (2002) C&D Materials Study, Conceptual Layout Study Report). 10.3.57 A trawl survey conducted under the Fisheries Resources Survey reported the highest mean catch weight per month was recorded from sites in southern waters, particularly South Cheung Chau, South Lantau, and South Lamma. As noted in the C&D Materials Study, (Conceptual Layout Study Report, March 2002), whilst the data collected under the Fisheries Resources Survey was from a single survey, the findings run contrary to the relative production estimates from the fisher and port surveys. This indicates that the area is potentially richer in resources than its current exploitation rate would imply. 10.3.58 Evidence for a nursery zone within Area 30 was also found from trawl survey, regular survey, interviews and site observations that appeared to show that there was a high abundance of juveniles in the area. The site footprint covers an area of 850ha, and coincides with that of the disposal ground. Whilst evidence exists for potential spawning grounds with fishing Area 30 as a whole, dumping activities at the site, suggest that spawning grounds are unlikely to be directly affected. It should be noted that there is a slight increase of suspended solids at NS3, but this is not significant (< 2mg/L above baseline). 10.3.59 The nearest fish culture zones are some distance away, on eastern Lamma (12km distant) and southern Lantau (7.5km distant). These would not be affected. Impacts on the nearby Fish Culture Areas in Mainland waters (i.e. MF7, MF8 and MF9) will be insignificant due to the dispersion effect. 10.3.60 The results from models show that there are no significant operational changes in water quality and hydrodynamics. Hence, the overall impacts on fisheries resources will not be significantly affected relative to the current situation. Cultural Heritage 10.3.61 There is no immediate evidence of any significant archaeological remains in this area. However on nearby Cheung Chau there is a rock carving that has been designated as a declared monument (the Cheung Chau Rock Carving). It is believed that the carving was carried out about three thousand years ago by early seafarers inhabiting the area and was intended as a magical symbol of the appeasement of the powers of the sea, or to invoke their protection. This suggests that seafaring people used the natural harbour of Cheung Chau for a considerable period. 10.3.62 Recognising the extent of mud disposal activities in this area over the past 20 years, archaeological impacts are not anticipated to be significant. However, given the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
10 ERM-Hong Kong Ltd (1998) Fisheries Resources and Fishing Operations in Hong Kong Waters, Agriculture & Fisheries Department, Hong Kong Government.
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Landscape and Visual 10.3.63 Landscape Planning Designations - this area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 10.3.64 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 10.3.65 Landscape Character – the proposed landfill lies in the Southern Coastal Waters LCA (Figure 10.4). The landscape of this part of Hong Kong is characterised by a generally expansive and open extent of water with numerous distant islands on the horizon, including Lantau, Cheung Chau and Lamma as well as islands in PRC territorial waters (Figure 10.3). These islands appear natural and unspoilt and provide a coherent, varied and relatively complex landscape. Shipping introduces movement and artificial elements into what is otherwise a predominantly natural landscape. 10.3.66 There exists potential for substantial impacts on landscape character resulting from construction works which will introduce new artificial elements which are incompatible with the existing landscape. During the afteruse phase of the island landfill, these impacts are likely to be reduced somewhat, as the completed island is restored. However, somewhat artificial character of the proposed island will be inconsistent with the natural character of the landscape. As a consequence of this, the long-term impact on landscape character will be reduced from moderate to substantial. 10.3.67 VSRs – VSRs affected by the proposals are identified in Tables 10.3 and 10.4. The extent of the project visual envelopes is shown in Figure 10.5. Because of the location of the proposed site, there are no large areas of population close to the site. Other VSRs (such as those on vessels) are often transient. Generally, VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as distant artificial elements, contrasting with the coherent qualities of existing landscape views (Figure 10.6). Generally, visual impacts will be moderate during construction/operation. After the restoration of the landfill island, the visual impact of the island will be reduced to slight to insubstantial for most VSRs given the remote location of the island. The exception to this is the VSR group at Cheung Chau where the visual impact will be moderate. 10.3.68 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 10.8.
Landfill Gas 10.3.69 There are no sensitive receivers (targets) or pathways within 500m of the site. Therefore, there are no potential off-site landfill gas hazards. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 10.3.70 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
10.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 10.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to South Cheung Chau.
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Air Quality 10.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 10.4.3 No specific noise mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5). Water Quality 10.4.4 Although no WQO exceedances were predicted during either the operation or the construction phase, there were WQO exceedances in TIN in all baseline, construction and operation phases. In addition, mitigation could still be required to prevent impacts during dredging and filling for the artificial island reclamation subject to the confirmation of the filling and dredging rate. Construction procedures, defining the rates and method of dredging and filling taking into account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in any EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments. In addition, specific protection may be required to protect the cooling water intake at the Lamma Power Station.
Solid Waste 10.4.5 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Ecology 10.4.6 No specific measures to protect areas of ecological value are deemed necessary at this stage; the application of measures to prevent unacceptable impacts on water quality will also apply to ecological resources. It is envisaged that given adequate edge protection design, assemblages typical of those adapted to hard substrates would colonise the rubble mound sea wall of the artificial island.
Fisheries 10.4.7 Mitigation applied for the protection of ecological resources would apply equally to the protection of fisheries resources.
Cultural Heritage 10.4.8 No specific measures for the protection of cultural heritage are deemed necessary at this stage. This should be re-evaluated in the event that a marine archaeological assessment is carried out as part of an EIA if this site is investigated further.
Landscape & Visual 10.4.9 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 10.8.
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10.5 Summary 10.5.1 A summary of the SEA for the SCCIL is provided in Tables 10.1 and 10.2:
Table 10.1: South Cheung Chau Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment 1 Distance to areas of air O There are no ASRs within 500m of the site. sensitive land use 2 Presence of topographic O There are no features which would affect air dispersal. In features which could addition as there are no ASRs within 3km, this criterion is not decrease or exacerbate applicable. impacts 3 Occurrence of O / - The predominant wind direction is towards ASRs. However the meteorological conditions remoteness of ASRs is such that this criterion is not applicable. which could exacerbate impacts 4 Cumulative Impacts of O Review of all known planning information (OZPs and the SWNT relevant emissions (TSP Development Strategy Review) indicate there are no other (construction), NOx, CO, confirmed or planned developments within 5km of this marine SO2 – LFG Flare) taking site, which could contribute to cumulative air quality impacts. into account ambient conditions 5 Total Emissions of Air O Waste will be delivered to the site by marine vessel and the Pollutants from the cumulative distance to be travelled is estimated to be 290km. territory-wide waste transportation between the RTSs and the site 6 Overall Impact O ‘Neutral’. Negligible air quality impacts due to its remote siting. Noise Assessment 1 Distance to areas of noise O There are no NSRs within 300m of the site. sensitive land use 2 Topographic Features O The area between the proposed landfill site and Cheung Chau (only applicable if there is marine (flat). Notwithstanding, as there are no NSRs within are NSRs within 300m) 3km this criterion is not directly applicable. 3 Cumulative Impacts of O No developments that could cause cumulative impacts. developments within 300m 4 Overall Impact O ‘Neutral’. Negligible noise impacts on surrounding NSRs due to its remote siting.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial island. Not relevant 2 Potential for sediment O The site is a designated ground for dumping of uncontaminated contaminant release dredged muds. The potential for impacts associated with contaminated muds is limited.
3 Potential impacts on O / - Potential impacts considered limited. Nearest beaches (on WSRs Cheung Chau – Kwan Yam Wan over 4.5km), are not within the main flow channels. Modelling predicts that SS WQO will be exceeded in both the wet and dry season during construction.
It is predicted that both DO and TIN standards in the operational phase would be breached, however, these were both breached in the baseline scenario and the elevations due to the presence of island were not significant, therefore, the island would not be the cause of the exceedances. 4 Potential Impacts on O Artificial island. Not relevant. Groundwater 5 Potential Cumulative O No major marine developments currently planned around the Impacts (Potential for site. The possible Lamma breakwater requires further concurrent projects to investigation once the status of the breakwater is ascertained. exacerbate preceding impacts) 6 Overall Impact O / - Potential water quality impacts are considered to be ‘Neutral / Negative – Low’. The area has been a mud disposal ground for over 17 years and has thus been subject to impacted water quality for many years. Waste Management Assessment 1 Balance of Materials + The site could accommodate major volume of public fill (surplus/deficit of public fill (225Mcum) negating the need to import filling material for site needed for landfill formation. Dredged muds will be incorporated with the fill development) materials within the island footprint. 2 GHG emissions from O Waste will be delivered to the site via marine vessel. The mode of transport for distance travelled from marine RTS(s) to the site has been delivery of waste to the estimated to be 290km. site from RTSs 3 Overall Impact + ‘Positive’.
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary O / - Limited impacts anticipated. The nearest protected areas are environmental impacts on the proposed Soko Islands and South Lantau Marine Parks “Areas of Absolute (7.2km and 10.3km respectively) to the west. The proposed S Exclusion” Lamma Marine Park is 9km to the east. 2 Affects an important O / - The proposed site is a marine disposal ground and the seabed habitat habitat is of relatively low ecological value (compared to undisturbed sea-bed). Nearest habitat of interest is moderate value corals at Soko’s. 3 Affects species of O / - This site is likely to disturb an area where Finless Porpoise conservation importance occur, although the density of sightings in this area is only moderate. 5 Potential for Cumulative O No major marine developments currently planned around the Ecological Impacts on site. The possible Lamma breakwater requires further sites of recognised value investigation once the status of the breakwater is ascertained. 6 Overall Impact O / - Ecological impacts are considered to be ‘Neutral / Negative – Low’. The site is not a core area for identified marine mammals, and those individuals surveyed have been recorded despite the historical effects of mud dumping. Most ecological receivers of importance are remote from the site and no significant impacts are envisaged. Fisheries Assessment 1 Potential for secondary O / - The site would not impinge on any areas of Absolute Exclusion, environmental impacts on (eg. Fish Culture Zones) “Areas of Absolute Exclusion” 2 Affects important O / - This site is within an area of commercially valuable fisheries. mariculture/ fisheries However, assuming sediment impacts are not exacerbated resources (including significant above existing, impacts are not considered likely to spawning / nursery be significant. ground) 3 Potential for Cumulative O No major developments planned within the area of the site. The Fisheries Impacts on sites status of the Lamma breakwater would require further of recognised value investigation if this site is pursued 4 Overall Impact O / - The site is within and area generally recognised as having a high fisheries potential. However, the potential fishery impacts are considered to be ‘Neutral / Negative – Low’, on the basis of the long history of mud dumping.
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Impacts Score Commentary
Cultural Heritage Assessment 1 Important cultural O There are no known sites of cultural heritage significance. (Declared, Deemed or Graded sites) / archaeological sites 2 Potential for O / - The potential for archaeological finds in this site is considered archaeological value limited due to previous disturbance. However, given the lack of archaeological data currently available, the need for a detailed marine archaeological investigation should be reviewed in future studies, particularly when preparing the EIA Study Brief. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land based, (on Heritage Impacts on sites Shek Kwu Chau (2.6km) and on Cheung Chau – over 2.8km of recognised value away). They will be unaffected by this development. There are no planned or confirmed projects, which may cause cumulative heritage impacts. 4 Overall Impact O Cultural heritage impacts are considered to be ‘Neutral’. The extensive site disturbance resulting from dredging significantly limits the potential for archaeological finds. Recognising the current uncertainty related to lack of information, this is subject to verification. Landscape and Visual Impact Assessment 1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts on landscape resources will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no significant Resources impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral. 3 Impacts on Landscape - - The open, natural character the Southern Coastal Waters Character Landscape Character Area will be significantly affected by the proposals. Resulting impacts will be Negative High. 4 Visual Impacts - / - - The location of the island is at a considerable distance from most populated areas and as a result will generally only have a moderate or slight impact on their visual amenity. Recreational receivers on Cheung Chau will be most impacted by the proposal. Overall visual impacts will be ‘Negative – Low / High’. 5 Overall Impact - / - - Overall, landscape and visual impacts will be ‘Negative – Low / High’ for the following reasons: • There are no landscape designations covering the disposal site. • The site is a marine one and so no significant landscape resources are affected; • There will be significant impacts on the open and natural character of the Southern Coastal Waters LCA. • There are relatively low numbers of visual receivers close to the site.
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Impacts Score Commentary
Landfill Gas Assessment 1 Distance between the new O This is a marine site located over 3km south of Cheung Chau, / extended landfill and SRs the nearest sensitive receivers are >250m away 2 Number of Receivers O There are no SRs within 500m within 250m (i.e. Consultation Zone) 3 Man-made / Natural O None Pathways for LFG Migration 4 Additional Utilisation of O LFG would be utilised on-site. There are no potential off-site LFG to Reduce GHG users of LFG. Emissions 5 Overall Impact O ‘Neutral’.
Table 10.2: Summary of South Cheung Chau Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O Neutral Overall Noise Impact O Neutral Overall Water Quality Impact O /- Neutral / Negative – Low Overall Waste Management Impact + Positive Overall Ecological Impact O / - Neutral / Negative – Low Overall Fisheries Impact O / - Neutral / Negative – Low Overall Cultural Heritage Impact O Neutral Overall Landscape & Visual Impact - /- - Negative – Low / High Overall Landfill Gas Impact O Neutral
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Table 10.3 Assessment of Significance of Visual Impacts for South Cheung Chau Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Approx No.s of VSRs Magnitude of VSR Impact Significance Significance of No. of Sensitive Receiver Minimum (order of Impact During Sensitivity before Mitigation Residual Impacts VSR (VSR) Distance magnitude only) Construction / (Low, Medium, Measures (Insubstantial, Slight, Between VSR Operation High) (Insubstantial, Slight, Moderate, Substantial) and Source(s) Moderate, Substantial) (Negligible, Small, Intermediate, Large) Residential VSRs VR50 Cheung Chau 3km Many Intermediate High Moderate to Substantial Moderate VR51 Sea Ranch 8km Very Few Small High Moderate Moderate VR52 Yung Shue Wan 10km Many Small High Slight Slight
VR53 Pokfulam 15km Very Few Negligible High Insubstantial Insubstantial Occupational VSRs VR54 Lamma Power Station 10km Very Few Small Low Insubstantial to Slight Insubstantial VR49 Maritime Vessels 5km Very Few Intermediate Low Slight to Moderate Slight Recreational VSRs
VR55 Cheung Chau 2.5km Many Intermediate High Moderate to Substantial Moderate VR20 N/S Lantau Country 6.5km Very Few Negligible Medium Insubstantial Insubstantial Parks VR56 Lantau Trail 8km Very Few Intermediate High Moderate to Substantial Moderate VR57 Lamma Lookout Point 10.5km Very Few Small High Moderate Moderate to Slight pavilion at Headland on trail between Hung Shing Yeh Beach and Soh Kwu Wan, VR11 Area for Boating, 0 - 10km Very Few Large High Substantial Substantial to Moderate Fishing and Diving Activities (varies) VR58 Victoria Peak 16km Many Negligible High Insubstantial Insubstantial Travelling VSRs
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Identity Key Visually Approx No.s of VSRs Magnitude of VSR Impact Significance Significance of No. of Sensitive Receiver Minimum (order of Impact During Sensitivity before Mitigation Residual Impacts VSR (VSR) Distance magnitude only) Construction / (Low, Medium, Measures (Insubstantial, Slight, Between VSR Operation High) (Insubstantial, Slight, Moderate, Substantial) and Source(s) Moderate, Substantial) (Negligible, Small, Intermediate, Large) VR40 Macau/ Sea Ranch 5km Few Small Medium Slight Insubstantial Ferries VR59 Lamma/ Cheung 10km Few Small Medium Slight Insubstantial Chau Ferries
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Table 10.4 Assessment of Significance of Visual Impacts for South Cheung Chau Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Approx No.s of VSRs Magnitude of VSR Impact Significance Significance of No. of Sensitive Receiver Minimum (order of Impact During Sensitivity before Mitigation Residual Impacts VSR (VSR) Distance magnitude only) Afteruse (Low, Medium, Measures (Insubstantial, Slight, Between VSR (Negligible, Small, High) (Insubstantial, Slight, Moderate, Substantial) and Source(s) Intermediate, Large) Moderate, Substantial) Residential VSRs VR50 Cheung Chau 3km Many Intermediate High Moderate to Substantial Moderate VR51 Sea Ranch 8km Very Few Small High Moderate Slight VR52 Yung Shue Wan 10km Many Small High Slight Slight to Insubstantial
VR53 Pokfulam 15km Very Few Negligible High Insubstantial Insubstantial Occupational VSRs VR54 Lamma Power Station 10km Very Few Small Low Insubstantial to Slight Insubstantial VR49 Maritime Vessels 5km Very Few Intermediate Low Slight to Moderate Slight to Insubstantial Recreational VSRs
VR55 Cheung Chau 2.5km Very Few Intermediate High Moderate to Substantial Slight to Insubstantial VR20 N/S Lantau Country 6.5km Very Few Negligible High Insubstantial Insubstantial Parks VR56 Lantau Trail 8km Very Few Intermediate High Moderate to Substantial Slight to Insubstantial VR57 Lamma Island, 10.5km Very Few Small High Moderate Insubstantial Lookout Point pavilion at Headland on trail between Hung Shing Yeh Beach and Soh Kwu Wan, VR11 Area for Boating, 0 - 10km Very Few Large High Substantial Moderate to Slight Fishing and Diving Activities (varies) VR58 Victoria Peak, Hong 16km Many Negligible High Insubstantial Insubstantial Kong Island
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Identity Key Visually Approx No.s of VSRs Magnitude of VSR Impact Significance Significance of No. of Sensitive Receiver Minimum (order of Impact During Sensitivity before Mitigation Residual Impacts VSR (VSR) Distance magnitude only) Afteruse (Low, Medium, Measures (Insubstantial, Slight, Between VSR (Negligible, Small, High) (Insubstantial, Slight, Moderate, Substantial) and Source(s) Intermediate, Large) Moderate, Substantial) Travelling VSRs VR40 Macau/ Sea Ranch 5km Few Small Medium Slight Insubstantial Ferries VR59 Lamma/ Cheung 10km Few Small Medium Slight Insubstantial Chau Ferries
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11. LAMMA BREAKWATER ISLAND LANDFILL 11.1 Basic Information Project Title 11.1.1 Lamma Breakwater Island Landfill, (LBIL) marine site M.6. Nature of Project 11.1.2 The Project would form a new marine based waste disposal site to the south west of Lamma Island (Figure 11.1). 11.1.3 The LBIL would require construction of an artificial island of approximately 585ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. 11.1.4 Construction works would be as described in Part A, Section 3.2. In addition works for the LBIL would include: - Dredging of about 10Mcum of underlying muds for construction of an outer seawall.
Location and Scale of Project 11.1.5 The LBIL is situated 2.5km to the west of Lamma Island and about 5km south east of Cheung Chau. Seabed levels in this area vary from 15 to 20m below Chart Datum. 11.1.6 The LBIL would cover an area of 585ha to an elevation of +6mPD. The artificial island would accommodate a landfill with a capacity of 130Mcum to an elevation of +56mPD. The site would accommodate approximately 225Mcum of fill material.
History of Site 11.1.7 The site falls within the Hong Kong Island South & Lamma Island Planning and Development Study, and is on the boundary of the South West New Territories Development Strategy Review area. The site coincides with that previously considered for developed as a possible breakwater to facilitate port operations. The coastal marine waters around south Lamma have been proposed for protection as a Marine Reserve / Park.
Number and Types of Designated Projects Covered 11.1.8 The LBIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. 11.2 Outline of Planning and Implementation Programme 11.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 11.2. Assuming landfill operations start in 2019, LBIL would be full during the period 2035 to 2045, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 11.2.2 The site is currently not covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 11.2.3 The Recommended Development Strategy formulated under the South West New Territories Development Strategy Review identified the potential of Cheung Chau and Lamma as tourist and recreation developments; this recognised their mountain scenery, appealing coastal areas and the large number of archaeological and historical sites.
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11.2.4 Lamma Island lies to the east of this site and is covered by the Lamma Island OZP Plan no. S/I – LI/3 issued in October 2001. The general planning intentions of the Lamma Island OZP are to conserve the natural landscape, the cultural heritage, the rural character and the car- free environment of Lamma Island; and to enhance the role of Lamma Island as a leisure destination. The Island has been subject to further investigation under the Planning and Development Study on Hong Kong Island South and Lamma Island. 11.2.5 The LBIL coincides partly with one of the sites proposed for development under the C&D Materials Study. 11.2.6 The LBIL also coincides partly with a site proposed for development of a breakwater under the PADS Studies. The PADS breakwater was proposed to provide protection to the Lantau Port and create an additional area of sheltered anchorage within the Western Harbour. The landward side of the breakwater was proposed to provide about 400ha of reclaimed land for port backup, although no specific usage was identified in the Lantau Port & Western Harbour Development Studies. Subsequently this site was identified in the Recommended Strategy under the South West New Territories Development Strategy Review as a “Possible Breakwater” and an area for “Possible Special/Port Related Industries”. The Port and Maritime Board have advised that the status of the “Lamma Breakwater” in the Port Development Programme is linked to the identification of a new container terminal site; a number of sites for which were considered under the Port Development Strategy Review. A new study on Hong Kong Port – Master Plan 2020 started in the second half of 2002 and will formulate a master plan for port development for the next 20 years. 11.3 Possible Impacts on the Environment 11.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the LBIL are outlined below. Figure 11.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 11.1 and 11.2.
Air Quality 11.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation (following reclamation). • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
11.3.3 There are no air sensitive receivers within 500m of the site. The nearest ASRs are isolated village houses on South Lamma at a distance of approximately 5km. As the site lies in an open marine area (i.e., no airshed) there would not be any accumulation of air pollutants. The HEC Lamma Power Station is located at some distance from the site - some 4km to the north. Significant air quality impacts are not anticipated. 11.3.4 This is a marine site and waste will be delivered to the site by marine vessel. The amount of air pollutants resulting from the territory-wide waste delivery (per kg of waste deposited at the site) is anticipated to be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is 250km. As such, no regional impacts are expected to arise from waste delivery.
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Noise 11.3.5 The reclamation and landfill development has the potential to cause the following noise impacts:
• construction – from dredging, tipping, piling works and general construction activities; • operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
11.3.6 No noise sensitive receivers have been identified within 300m of the site; The nearest NSRs are on South Lamma, at a distance of approximately 5km to the east. Significant noise impacts are not anticipated. However, potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other landuses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 11.3.7 Whilst it is not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an off-shore reclamation site with no noise sensitive receivers in the vicinity, the more stringent requirements for noise emissions during the evening and night time periods are not expected to be an issue for this site. 11.3.8 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicle is not a concern for this site.
Water Quality Baseline Conditions at the Site 11.3.9 The site is located within the Southern Water Control Zone (WCZ). This area has converging / diverging currents. Flood and ebb currents split into two branches, one flowing north/south to Ma Wan, and the other flowing east / west toward the Soko Islands. Currents are generally low, with the velocity of flood flows reduced by the presence of Lamma island, (ERM 1997b1). 11.3.10 Background water quality conditions have been established from EPD routine monitoring stations, the latest available data being that collected in 2000, (EPD 20012). The site is situated in the western waters of Hong Kong which are generally characterised by elevated levels of suspended solids, (compared to Eastern Waters) as a result of the influence of the Pearl River Estuary. Locations of the nearest routine EPD water quality monitoring stations (SM5, SM6, SM7 and SM18) are presented in Figure 11.1. 11.3.11 Water quality data for 2000 at the monitored stations indicates full compliance with the Southern WCZ Water Quality Objectives (WQOs) for key parameters such as dissolved oxygen, (DO), E. Coli, and un-ionised ammonia. However, consistent with long-term trends (data measured annually since 1991) levels of total inorganic nitrogen (TIN) exceeded WQOs at all stations. 11.3.12 The nearest regular EPD sediment monitoring station in this area is SS3, which lies approximately 240m to the north. Sediments at SS3 are considered to be uncontaminated according to EPD data. The potential for impacts associated with contaminated marine muds is considered limited.
1 ERM-Hong Kong Ltd (1997b) Site Search for a New Power Station: Preliminary Site Search (Revised Final Technical Report No. 2), Hongkong Electric Company, Ltd.
2 EPD (2001) Marine Water Quality in Hong Kong (in 2000). Environmental Protection Department, Hong Kong Government.
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Key Issues and Sensitive Receivers 11.3.13 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
11.3.14 Identified Water Sensitive Receivers (WSRs) present in the vicinity of the site are:
• Cooling water intake for HEC Lamma Power Station (5km); • Gazetted beach near the Power Station at Hung Shing Ye (5.2km); • Gazetted beaches at Lo So Shing, SW Lamma (4.2km), and Cheung Chau (6km); and • Secondary contact recreation sub-zone around the west and south Lamma coastlines.
11.3.15 In addition, there are a number of ecological resources around the project area that may be sensitive to any decline or change in water quality or sediment deposition / erosion patterns. Potential impacts upon these are discussed in the “Ecology” subsection. These receivers include:
• Green Turtle nesting habitat at Lamma Island Sham Wan beach; • Core habitat area for the Finless Porpoise at Ha Mei Tsui; and • General Marine and coastal waters around the proposed South Lamma Marine Park / Reserve.
11.3.16 The locations and uses of the WSRs are shown in Figure 11.1 Reclamation and Site Formation 11.3.17 Due to the exposed location of the site, localised dredging is likely to be necessary for the seawalls prior to construction of the reclamation. The dredged material can be placed within the footprint of the reclamation, reducing transport and spillage losses. 11.3.18 The placement of fill for island construction is also likely to lead to localised increases in suspended solid levels. The hydrodynamic and water quality modelling indicated that although no WQO exceedences were predicted, the suspended solids levels would increase at FP2 (13.95%), SC20 (12.00%), NS2 (19.15%), NS1 (15.23%) and FP8 (20.90%) in the dry season during the Phase 1 construction. Increases were also predicted at FP1 (16.10), MP6 (16.37%) and NS4 (18.61%) during the wet season. During Phase 2 construction increases were predicted at SC20 (16.24%), NS2 (19.15%) and FP8 (28.03%) in the dry season and at FP1 (17.41%), MP6 (19.20%) and NS4 (21.05%) in the wet season. During Phase 3 construction increases were predicted at NS2 (16.67%) and FP8 (28.27%) in the dry season and FP1 (17.13%), MP6 (18.44%) and NS4 (20.11%) in the wet season.
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Hydrodynamic and Water Quality Impacts Following Island Formation 11.3.19 The presence of the artificial island is predicted to significantly increase the accumulated flow through the East Lamma Channel (45.02%) and to reduce the flow in the West Lamma Channel (32.03%) during the dry season. In the wet season, a reduction in accumulated flow is predicted in all three major channels of between 4.26% (East Lamma Channel) and 7.91% (Tathong Channel). The presence of the artificial island is predicted to significantly increase the velocity between the island and Lamma Island during the neap ebb tide and to cause some significant changes in flow pattern between Peng Chau and Lamma Island during the neap flood tide in the wet season. In the dry season, the velocity was predicted to increase between the island and Lamma Island and around the western part of the island during the spring ebb tide. Significant increases in flow velocity were also predicted around the island during neap ebb tide. The overall average current magnitude was predicted to increase by up to 23.59% to the north-east of the island. 11.3.20 In the hydrodynamic and water quality modelling, the relative differences in tidal flux between major channels, including Victoria Harbour, East and West Lamma Channels and Adamasta Channel, were investigated. It is predicted that the presence of the island would cause a small increase in the accumulated fluxes in Victoria Harbour (ranged from 0.96% to 2.74%) for all tide phases except during the wet season neap flood period when there would be a small reduction in the calculated fluxes (-3.02%). 11.3.21 It also predicted that the island would increase the accumulated fluxes in East Lamma Channel for all tidal phases (ranged from 1.08% to 7.25%), however, decrease in the fluxes would occur in West Lamma Channel for all tidal phases (ranged from -4.87% to -9.66%). 11.3.22 However, the effect on Adamasta Channel would be quite large. The model predicted that there would be increases in the tidal fluxes through the channel at all tide phases (that ranged from +6.05% to +89.66%). 11.3.23 Overall, the presence of the island would, in general, reduce the fluxes through West Lamma Channel and redistribute flow to the remaining three channels. East Lamma Channel would receive the largest proportion of the West Lamma Channel flow. The effect of the overall changes in the flow discharges through the four channels would however be small based on the finding that the net reductions were within 1%, and therefore, the pollutant dispersion capability of harbour west area would only be marginally reduced. 11.3.24 In the hydrodynamic and water quality modelling, 17 sensitive receivers that are close to the site were selected for presentation. Of the 17 chosen indicator points, 15 of them (FP8, GB4, FC2, GB11, FP2, CW4, FP1 and MP6) are located in the Southern WCZ. While the remaining 2 (MF8-9) are located in Mainland waters and classified as Category 2 in the Mainland Sea Water Standard. 11.3.25 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.38 to 7.43mg/L which complied with the WQOs of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO as well as the Mainland standard of 5mg/L. Comparing to the baseline water quality results, the percentage differences are minimal (ranged from 0.15 to 1.82%). 11.3.26 The predicted average dry season salinity ranged from 33.86 to 34.00ppt. The differences in salinity levels caused by the presence of the island were also minimal (less than 1%) at all the selected indicator points as compared to the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 11.3.27 The predicted dry season SS levels at the indicator points were in the range of 3.82 to 5.63mg/L. The largest difference of 3.98% and 3.81% were predicted at NS2 (Fishery Nursery/Spawning Ground South of Nam Tam Wan, Cheung Chau) and NS1 (Fishery Nursery/Spawning Ground South of Pak Tso Wan, Cheung Chau) respectively. Compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, these differences are considered very small.
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11.3.28 The change in average dry season E.coli levels caused by the presence of the island is significant at Stations GB4 (Gazetted Beach at Silvermine Bay) and FC2 (Fish Culture Zone at Cheung Sha Wan). For FC2, there would be a 140% increase of E.coli levels. However, the predicted E.coli levels at this station with value of 24count/100mL would be quite small when compared with the WQO of 610cfu/100mL. The predicted average E.coli levels for the remaining indicator points were low (1 – 18count/100mL). 11.3.29 The predicted average dry season UIA levels (0.000778 – 0.00350mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L and the Mainland standard of 0.020mg/L. 11.3.30 The predicted dry season TIN levels (0.0906 – 0.0913mg/L) at the 2 indicator points were very small and well below the Mainland standard of 0.3mg/L. Since the Hong Kong WQO of TIN is an annual mean value, the predicted mean TIN levels at the indicator points in Hong Kong waters for the dry and wet seasons were averaged to represent the annual mean values. All 15 indicator points in Hong Kong waters breached the WQO of 0.1mg/L with calculated annual mean values ranging from 0.1013 to 0.1984mg/L. However, the calculated averaged baseline concentrations at these stations also exceeded the WQO. 11.3.31 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average and for bottom DO ranges from 4.73 to 6.97mg/L. The values complied with the WQOs of ≥4mg/L for depth-average and ≥2mg/L for bottom DO as well as the Mainland standard of 5mg/L. Four indicator points, namely GB11 (Gazetted Beach in Cheung Chau), CW4 (Cooling Water Intake at Lamma Island), FP2 (Finless Porpoise Area near Cheung Chau) and NS2 (Fishery Nursery/Spawning Ground South of Nam Tam Wan, Cheung Chau), showed reductions in DO levels in comparison with the baseline values. The percentage reduction ranged from 0.18 to 2.24%. 11.3.32 The predicted average salinity in the wet season ranged from 19.20 to 25.10ppt. Comparing to the baseline water quality results, the differences in salinity caused by the presence of the island were small ranging from 0.72 to 4.04%. The differences were below the WQO requirement of 10%. 11.3.33 The predicted SS levels in the wet season at the indicator points were in the range of 4.50 to 8.40mg/L. The percentage differences ranged from 0.37 to 10.83% with the largest difference at GB4 (Gazetted Beach at Silvermine Bay). Compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, the differences are considered small. 11.3.34 The predicted wet season E.coli levels ranged from 1 to 32count/100mL which is well below the WQO of 610cfu/100mL and the Mainland standard of 200count/100mL. 11.3.35 The predicted average wet season UIA levels (0.00374 – 0.00558mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L for annual mean and the Mainland standard of 0.020mg/L. The largest increase compared with the baseline scenario was at NS3 (Fishery Nursery/Spawning Ground Southwest of Cheung Chau) with a percentage difference of 5.42%. 11.3.36 The predicted wet season TIN levels (0.2241 – 0.2779mg/L) at the indicator points in Mainland were below the Mainland standard of 0.3mg/L. However, the predicted TIN levels (0.2682 – 0.3153mg/L) at the indicator points in Hong Kong waters were relatively higher as compared to the dry season data. All stations in Hong Kong waters breached the WQO of 0.1mg/L as discussed in Section 11.3.30 above. Cumulative Impacts 11.3.37 Currently, there are ongoing extensions including dredging and reclamation at the southern side of the Lamma Power Station. However, these works are scheduled for completion by mid 2003 and no cumulative water quality impacts are envisaged.
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11.3.38 The Lamma Power Station extension was investigated (along with others), as a potential site for construction of a Waste-to-Incinerator Energy Facility (WEIF). Whilst the final decision on this project, (i.e. preferred site and implementation programme) has not been made, the siting of a WEIF at Lamma was not recommended on environmental grounds (CDM 1998.3). For the purposes of this assessment it is assumed that any future facility would not be located at Lamma Island. 11.3.39 The site coincides with that for the potential Lamma Breakwater, which includes for port related back-up facilities. The potential for cumulative impacts lies in the future need for the Lamma Breakwater, the effects of which may be facilitated to some extent by the LBIL if this option is pursued. This issue will require further investigation and confirmation.
Waste Management / Disposal Impacts 11.3.40 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points across the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 11.3.41 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 11.3.42 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 225Mcum • Volume of muds to be dredged for the outer sea wall: 10Mcum
11.3.43 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 11.3.44 Regarding GHG emissions, waste delivery to the site will be by marine vessel which has a lower GHG emission rate (per kg waste handled) compared to road transport. Based on the information given in the Preliminary Marine Review (March 2002), it is noted that the cumulative distance between marine RTSs and the site is around 250km. According to the ranking scale (see Section 5), the GHG impacts are considered to be neutral.
Ecology Baseline Conditions 11.3.45 There are a number of ecological resources of conservation interest and significance in the general area of the LBIL, principally those located at South Lamma. The LBIL would be near to the Sham Wan SSSI and approximately 2km from the eastern edge of the proposed South Lamma Marine Reserve / Park. The potential LBIL would also be just over 2.3km from the Ha Mei Tsui headland at the southeast Lamma coastline. 11.3.46 Figure 11.1 shows the locations of ecologically sensitive areas in the vicinity of the site.
3 CDM (1998). Feasibility Study of Waste-to-Energy Incineration Facilities: Site Assessment Report – Lamma Island. Submitted to EPD, July 1998.
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11.3.47 The Green Turtle Chelonia mydas is the only turtle species known to breed locally, with nesting only reported thus far at the sandy beach at Sham Wan, south Lamma.4 The Green Turtle is protected under the Wild Animals Protection Ordinance, Cap.170 and is listed under Appendix I of CITES. The beach at Sham Wan and the nearby shallow waters were designated a SSSI in June 1999, whilst (since 1999) approximately 0.5ha of the nesting area including the beach is a “Restricted Area” between June and November. 11.3.48 The Black Finless Porpoise frequents the waters around the LBIL area and generally around south Lamma throughout the year. Seasonal distribution data collated by the AFCD shows that the waters around Ha Mei Tsui are a very important part of the species’ core habitat between September and May, with the peak season for the Finless Porpoise being between March and May (“Spring”). The Chinese White Dolphin prefers waters further to the west, although there have been occasional sightings in the site area.5 11.3.49 The area with the greatest concentration of Finless Porpoise sightings is immediately off the Ha Mei Tsui headland, South Lamma. The AFCD distribution map for the “Spring” period shows most sightings within a 1km radius from this headland: a total of 29 sightings, with most of these in waters 0.5-1km offshore. The exact reasons for the apparent concentration in activity at this location are not known, although it has been hypothesized that the unusual bathymetry in the few hundred metres closest to the headland provides a good habitat for the primary prey species of the Finless Porpoise. 11.3.50 Inter-tidal resources at southwest Lamma were investigated under the HEC Power Station Extension study. The macroinvertebrate and macroalgae community around Ha Mei Tsui was relatively diverse amongst the six west coast survey locations. The most abundant species were the Chiton Acanthopleura japonica, the Limpet Patelloida saccharina, and the macroalgae Neogoniolithon misakiense. None of the intertidal community species are of particular conservation significance. 11.3.51 The Power Station Extension study described the shallow sub-tidal waters at southwest Lamma, as being characterised by steep rocky substrate comprised of boulders. This substrate character (combined with the peninsula status of the location and the water current) appears to be conducive to coral establishment as the greatest coral diversity on the west Lamma coast is to be found in this area. Hard coral of the genus Tubastrea was reported as abundant on the southwest-facing coast, whilst three species of soft coral, three of sea whip, one sea pen and one sea fan were also observed in the 1998 survey. Other abundant coral reef associates reported in large numbers were the sea cucumber Colochirus crassus and the long-spined sea urchin Diadema setosum (ERM, 1999). It was concluded that the coastal sub-tidal habitat around Ha Mei Wan, southwest Lamma, is of “high ecological value”. Direct Habitat Loss 11.3.52 No specific surveys of the benthos at the site area have been carried out, however given the depth of water at this site approximately 20m, it is reasonably anticipated that hard corals would be absent due to the low light levels, although the presence of soft corals and gorgonians cannot be discounted, (ERM 1997c6). It is expected that benthic communities will be representative of similar communities in southern waters as surveyed by Shin and Thompson, (1982), dominated by polychaetes, molluscs and crustaceans. It is anticipated that the benthic community will generally be of low ecological significance.
4 AFCD (2001). AFCD Website. Conservation: Protection of Green Turtles. [www.afcd.gov.hk/con_new/turtle.htm]. 5 AFCD (2001). AFCD Website. Conservation: Chinese White Dolphin. www.afcd.gov.hk/con_new/cdp_ distri4.htm].
6 ERM-Hong Kong Ltd (1997c) Stage 1 EIA for a New Power Station: Stage 1 EIA Report Volume I, Hongkong Electric Company, Ltd.
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11.3.53 The site footprint covers a surface area of 585ha and the site is entirely sub-tidal. It is anticipated that there will be no benthic species of particular ecological significance in the area. 11.3.54 Using AFCD data, the total number of sightings of Finless Porpoise at set distances from the Ha Mei Tsui headland has been identified. The number of sightings in consecutive 500m “bands” from the headland is as follows:
Distance # Finless Porpoise Cumulative Total within 3km (%) Sightings 0.0 – 0.5km 8 13 0.5 – 1.0km 21 46 1.0 – 1.5km 12 65 1.5 – 2.0km 10 81 2.0 – 2.5km 5 89 2.4 – 3.0km 7 100 0.0 – 3.0km 63 100
11.3.55 The data confirms that the highest number of sightings (33%) occurs between 0.5km and 1km from the headland, with over 80% of sightings within 2km of the Ha Mei Tsui headland. The distance between the headland and the potential LBIL is approximately 2.3km. There has also been a further amendment in the LBIL footprint to move the site some 500m further west of the location indicated in the Draft SEA, thereby further increasing the distance from the apparent core area for the Finless Porpoise. 11.3.56 The above table has been generated from AFCD data to provide an indication of the distribution of Finless Porpoise sightings in the waters in between the Ha Mei Tsui headland and the potential location of the LBIL. For the purpose of this SEA the AFCD data has been simply presented to try and define more accurately the “core” area for the Finless Porpoise. The results of this exercise are that the core area does not overlap with the potential LBIL site, although given the inherent secrecy of the Finless Porpoise it would be prudent that this issue is further investigated at the detailed EIA stage. 11.3.57 The final configuration of the LBIL would also be subject to more detailed investigation at the detailed design stage and would be affected by the findings of further investigation into the distribution and behaviour of the Finless Porpoise off southwest Lamma Island. 11.3.58 The Finless Porpoise may also be prone to adverse impact from general disturbance associated with landfill development and operation, including vessel noise / vibration. Whilst it is known that vessel collision is a significant source of mortality for the Finless Porpoise, the mammal would be able to avoid impacts to a certain extent and it is also recommended that marine vessel access to any future LBIL be routed to avoid the coastal waters of South Lamma and the Ha Mei Tsui headland as far as practicable. 11.3.59 The modelling results show that a slight increment (around 1mg/L) in suspended solids levels would occur and rise to a level < 6.5mg/L at FP1, MP6 and NS4 during Phase 2 construction in the wet season. This sediment concentration (1mg/L) rise to a level less than 6.5mg/L may also apply to NS4 during Phase 3 construction in the wet season. The resulting reduction in water quality may adversely affect the above sensitive areas. These areas include the Finless Porpoise Area, Potential Marine Park and Fishery Nursery/Spawning Ground, south to the southwest of Lamma Island. There are no operational changes in water quality.
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Water Quality / Hydrodynamics 11.3.60 The SSSI designated turtle breeding beach at Sham Wan (South Lamma) is protected from the effects of LBIL due to the coastal morphology. The Finless Porpoise, for which the area forms part of the core habitat, could be driven out by dredging and reclamation activities. Any deterioration in water quality would drive fish from the area due to their sensitivity to increased suspended sediment levels, resulting in reduced feeding opportunities for the Green Turtle and Finless Porpoise in these waters. Further discussion of potential impacts on the Green Turtle is discussed in Chapter 17, (Lamma South Island Landfill). Marine Vessel Disturbance 11.3.61 From a study conducted on behalf of the AFCD, it is known from data on strandings of Black Finless Porpoise specimens that vessel collision is a significant cause of death (Jefferson, 2001). As the South Lamma area is part of the core habitat for Finless Porpoise, any increase in marine traffic required for site formation / reclamation activities and facility operation could lead to an increase in incidences of vessel collision. 11.3.62 The marine waters in the area to the south of Lamma area are important for the Green Turtle. Given the location of the potential LBIL relative to the turtle’s nesting ground at Sham Wan, there is the potential for disturbance of the turtles during their breeding season.
Fisheries 11.3.63 There are two fishing zones in the vicinity of the LBIL: Ha Mei (zone 98) and Tai Kok (zone 99). Available data indicates that both of these zones are similarly popular in terms of the number of fishing vessels utilizing the zone compared against other fishing zones to the north (“North Lamma” report refers). Likewise, the productivity of these two zones is similar on a unit area basis. In terms of value ranking for adult fish, Tai Kok ranks 50 / 210 zones compared with 66 / 210 for Ha Mei. Ha Mei has slightly better ranking for fry fish 45 / 89 compared with 49 / 89 for Tai Kok. The overall value of both Tai Kok and Ha Mei were high for the HKSAR, ranking 84th and 70th respectively out of 210 fishing zones (ERM, 1999). 11.3.64 The numerical model predicts that the small increase in suspended solids levels during construction phases 2 and 3 in the wet season may temporally impose adverse impacts on the Fishing Nursery/Spawning Ground located South of Lamma Island (NS4). 11.3.65 The most commonly caught species in these two zones were the same, including the scad Caranx spp., the sardine Sardinella jussieui, and the croaker Argyrosomus spp. The catch of Mantis shrimp Oratosquilla spp. – a commercially valuable species – was the 5th most important in terms of species weight in both zones (ibid.). Other commercially important species for which the South Lamma area is a known spawning ground include the coastal mud shrimp Solenocera crassicornis, and the Jinga shrimp Metapenaeus affinis. The marine waters are also an important nursery area for the shrimp Metapenaeopsis barbata and M.palmensis, and croaker and grouper fry, amongst others (ERM, 1998). Due to their importance as a nursery area for commercial fish species it has been proposed that the waters around South Lamma be designated a Fisheries Protection Area (ibid.). 11.3.66 Overall, the construction of the LBIL has potential to create a significant adverse impact on fisheries resources in the area. Marine dredging works will have considerable potential to affect fisheries in the area; particularly on the ebb tide when the ebb tide current from the West Lamma Channel may transport sediment south from the works area and deeper into the productive fisheries grounds. General reclamation and site formation activities may also lead to adverse impacts from sediment dispersal away from the works location. 11.3.67 There are no fish culture zones in the area of the proposed LBIL. The nearest FCZ is located a considerable distance away on the eastern side of Lamma Island at Sok Kwu Wan.
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Cultural Heritage 11.3.68 There is no immediate evidence of archaeological remains in this area. However there are a significant number of archaeological sites on both Lamma and Cheung Chau. The presence of sites on land strongly suggests that seafarers would have used the natural harbours of the islands and the waters around the LBIL for several thousand years. 11.3.69 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 11.3.70 Landscape Planning Designations – This area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 11.3.71 Landscape Resources - The site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 11.3.72 Landscape Character – The island landfill site falls within the Southern Coastal Waters LCA (Figure 11.4). The landscape of this part of Hong Kong is exposed offshore water with little sense of containment other than distant islands in PRC waters and the distant islands of Lantau, Lamma and Cheung Chau (Figure 11.3). The area is given some landscape context by the proximity of Lamma Island. Shipping introduces movement and artificial elements into what is otherwise a predominantly natural setting. 11.3.73 There exists potential for substantial impacts on landscape character resulting from construction/operation works, which will introduce new elements which are incompatible with the existing open landscape. During the afteruse phase of the island landfill, these impacts are likely to be reduced, as the completed island is restored. The character of the island will be generally inconsistent with the open, natural character of the surrounding landscape. As a consequence of this, the long-term impact on landscape character will be moderate to substantial. 11.3.74 VSRs - VSRs affected by the island landfill are identified in Tables 11.3 and 11.4. The extent of the project visual envelopes is shown in Figure 11.5 and the key views to the island landfill are shown in Figure 11.6. 11.3.75 Because of the location of the island there are no large areas of population close to the site. VSRs that will be the most affected are residential VSRs in Nam Tam, Cheung Chau and recreational VSRs in Lamma Island Trail and visitors using these areas for boating, fishing and other water sport activities. Other recreational VSRs that will be less affected are the visitors to the Hung Shing Ye Beach, Fa Peng Beach and Lo So Shing Beach as their locations are further away from the island and at sea/ground level. Occupational VSRs are affected at Lamma Island Power Station. Other VSRs, such as travellers on vessels using the Shipping Lanes, are often transient. 11.3.76 The VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as relatively close artificial elements contrasting with the coherent natural qualities of the existing landscape. Resulting visual impacts will generally be substantial to moderate. After the restoration of the landfill island, the visual impact of the island will be reduced. The somewhat artificial profile of the island will however still contrast with the existing character of views (Figure 11.7). Therefore, the residual visual impact on major VSRs during the afteruse phase will be reduced to moderate to slight. 11.3.77 Mitigation Measures – Landscape and visual mitigation measures are outlined in Part A of the Report and are illustrated in Figure 11.8.
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Landfill Gas 11.3.78 There are no sensitive receivers (targets) or pathways within 500m of the site. Therefore, there are no potential off-site landfill gas hazards. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 11.3.79 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it would be used as an on-site energy source. 11.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 11.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are those which are site-specific.
Air Quality 11.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice.
Noise 11.4.3 No specific noise mitigation measures are recommended at this stage, other that good site practice.
Water Quality 11.4.4 Although no WQO exceedances were found during either the operation or the construction phase, there were WQO exceedances in TIN in all baseline, construction and operation phases. In addition, mitigation could still be required to prevent impacts during dredging and filling for the artificial island reclamation subjected to the confirmation of the filling and dredging rate. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in any EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments. In addition, specific protection may be required to protect the cooling water intake at the Lamma Power Station.
Solid Waste 11.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 11.4.6 Specific controls on vessel movements to minimise impacts on the Finless Porpoise are recommended if this site is investigated further. Tentatively, routing of marine vessels through waters away from the coastline of South Lamma and sufficiently far from the Ha Mei Tsui headland to avoid the “core” habitat (once more suitably defined by field investigation) is recommended. 11.4.7 The application of measures to prevent unacceptable impacts on water quality will also apply to ecological resources, and are likely to be necessary.
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11.4.8 Through the course of this SEA, the location of the LBIL within the site search envelope has been modified to increase the distance of the site from the core area for the Finless Porpoise. If the LBIL is selected for more detailed investigation, it is recommended that opportunities to maximise the distance of the site from the core area be investigated further.
Fisheries 11.4.9 Mitigation applied for the protection of ecological resources would apply equally to the protection of fisheries resources. Cultural Heritage 11.4.10 No specific measures for the protection of cultural heritage are deemed necessary at this stage. This should be re-evaluated in the event that a marine archaeological assessment is carried out as part of an EIA if this site is investigated further.
Landscape & Visual 11.4.11 Mitigation Measures – Landscape and visual mitigation measures are outlined in Part A of the Report and are illustrated in Figure 11.8.
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11.5 Summary 11.5.1 A summary of the SEA for the LBIL is provided in Tables 11.1 and 11.2: Table 11.1: Lamma Breakwater Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment 1 Distance to areas of air O There are no ASRs within 500m of the site. sensitive land use 2 Presence of topographic O There are no features which would affect air dispersal. In features which could addition as there are no ASRs within 3km, this criterion is not decrease or exacerbate applicable. impacts 3 Occurrence of O The predominant wind direction is towards ASRs. However the meteorological conditions remoteness of ASRs is such that this criterion is not which could exacerbate applicable. impacts 4 Cumulative Impacts of - Review of all known planning information (OZPs and the relevant emissions (TSP SWNT Development Strategy Review) indicate there are no (construction), NOx, CO, other confirmed or planned developments within 5km of this SO2 – LFG Flare) taking marine site, which could contribute to cumulative air quality into account ambient impacts. The HEC Lamma Power Station is located conditions approximately 4.2km to the north of the site. There are no ASRs located within 500m of the island site and hence no cumulative air quality impacts are anticipated. 5 Total Emissions of Air O Waste will be delivered to the site by marine vessel and the Pollutants from the cumulative distance to be travelled is estimated to be 250km. territory-wide waste transportation between the RTSs and the site 6 Overall Impact O Overall air quality impacts is considered to be ‘Neutral’ because local impacts are not anticipated due to the absence of ASRs within 500m. Noise Assessment 1 Distance to areas of noise O There are no NSRs within 300m of the site. sensitive land use 2 Topographic Features O The area between the proposed landfill site and the nearest (only applicable if there land mass Soko Islands is marine (flat). Notwithstanding, as are NSRs within 300m) there are no NSRs within 3km this criterion is not directly applicable. 3 Cumulative Impacts of O No developments that could cause cumulative impacts. developments within 300m 4 Overall Impact O ‘Neutral’. Negligible noise impacts on surrounding NSRs due to its remote siting.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial Island. Not Relevant. 2 Potential for sediment O None. EPD routine sediment quality monitoring data collected contaminant release near to the site indicates uncontaminated marine sediments. 3 Potential impacts on - Water quality modelling indicates that the construction of the WSRs island may cause some increase in SS but that this remains below the WQO.
It is predicted that TIN standard in the operational phase would breached, however, it was also breached in the baseline scenario and the elevation due to the presence of island was not significant, therefore, the island would not be the cause of the exceedance. The impact is assessed to be at the upper end of ‘Negative – Low’ category. In addition, the island will slightly reduce the flushing capability of Western Harbour.
4 Potential Impacts on O Artificial Island. Not Relevant. Groundwater 5 Potential Cumulative O There are no major marine developments currently planned Impacts (Potential for around the site that could result in cumulative impacts. The concurrent projects to site coincides with that for the potential Lamma Breakwater. exacerbate preceding The potential for cumulative impacts lies in the future status of impacts) the Lamma Breakwater which will require confirmation.
6 Overall Impact - Potential water quality impacts are considered to be ‘Negative – Low’. The works will result in increases in suspended solid levels during dredging / reclamation and potential reduction in flushing capacity of Ha Mei Wan during operation. Although LBIL was categorised as ‘Negative – Low’, the water quality impact, in fact, can either be in the upper end of ‘Negative – Low’ or lower end of ‘Neutral / Negative – Low’ category. It was finally categorized as ‘Negative – Low’ so that the relative differences in water quality impacts with respect to SCCIL can be illustrated.
Waste Management Assessment 1 Balance of Materials + The site could accommodate a major volume of public fill (surplus/deficit of public fill (225Mcum) negating the need to import filling material for site needed for landfill formation. Dredged muds will be incorporated with the fill development) materials within the island footprint. 2 GHG emissions from O Waste will be delivered to the site via marine vessel. The mode of transport for distance travelled from marine RTS(s) to the site has been delivery of waste to the estimated to be 250km. site from RTSs 3 Overall Impact + Overall the site is considered to have a ‘Positive’ impact due to the ability to accommodate surplus C&D material and the avoidance of land based secondary environmental impacts.
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary O The proposed S Lamma Marine Park is located some 2km to environmental impacts on the east. Hydrodynamic modelling indicates marginally “Areas of Absolute significant construction phase impacts in the wet season and Exclusion” insignificant operational phase impacts to the water quality or hydrodynamics which may affect this area. 2 Affects an important - / - - The site is in the vicinity of the core habitat for the Finless habitat Porpoise. There are also coral communities of high conservation value located at Ha Mei Tsui (southwest Lamma), these areas are situated at some distance from the site and therefore the impacts associated with water quality reduction are anticipated to be marginally significantly only. 3 Affects species of - - This site is located in the vicinity of the core area for the conservation importance Finless Porpoise. This Cetacean is listed under Appendix I of CITES and is protected under the Wild Animals Protection Ordinance (Cap. 170) and may suffer significant direct impacts, particularly during operation. 5 Potential for Cumulative O There are no known concurrent works in the vicinity of the Ecological Impacts on artificial island location that have potential to create cumulative sites of recognised value ecological impacts, however this would require verification on the basis of the final decision for the proposals for the Lamma Breakwater (and back-up facilities). 6 Overall Impact - /- - Ecological impacts are considered to ‘Negative – Low / High’ due to the close proximity to the proposed South Lamma Marine Park, and the core habitat for the Finless Porpoise. Fisheries Assessment 1 Potential for secondary O There are no existing “Areas of Absolute Exclusion” (eg. Fish environmental impacts on Culture Zones) that may be affected by the works. “Areas of Absolute Exclusion” 2 Affects important - - The two fishing zones in the vicinity of the potential artificial mariculture/ fisheries island are ranked highly in terms of fisheries productivity in the resources (including HKSAR. The waters around the potential site are an important spawning / nursery spawning and nursery ground for a range of commercially ground) important fish and crustaceans. It has been proposed that the waters around South Lamma are designated a “Fisheries Protection Area”. 3 Potential for Cumulative O There are no anticipated cumulative impacts. Fisheries Impacts on sites of recognised value 4 Overall Impact - The potential fisheries impacts are considered to be ‘Negative – Low’ due to minor sediment input to the fisheries and spawning grounds, south of Lamma Island (NS4) during the construction phase in the wet season.
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Impacts Score Commentary
Cultural Heritage Assessment 1 Important cultural O There are no known sites of cultural heritage significance. (Declared, Deemed or Graded sites) / archaeological sites 2 Potential for - No marine based deposits of archaeological interest have archaeological value been found in the site area, although there is evidence of land based archaeological finds nearby on Lamma Island. This suggests that the coastal area of Lamma Island has been used by seafaring people for several thousands of years. Recognising the lack of archaeological data currently available, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land based, (on Heritage Impacts on sites Lamma Island. Therefore they would not be affected by this of recognised value development. 4 Overall Impact - The potential impacts on cultural heritage are considered to be ‘Negative – Low’. Whilst there is not direct evidence of cultural heritage remains in the site area, the occurrence of remains on nearby Lamma Island increases the potential for marine archaeological finds.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts on landscape planning designations will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no significant Resources impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral. 3 Impacts on Landscape - - The island landfill will contrast with the open and natural Character character of the Southern Coastal Waters Landscape Character Area. The impact on this character area will be substantial reducing to moderate/substantial with the restoration of the island. Overall impacts on landscape character will be Negative – High. 4 Visual Impact - / - - The most affected VSRs will be residents in Nam Tam, Cheung Chau and a few recreational receivers who use that part of the sea area for active and passive recreation. The impact on these VSRs will be substantial to moderate. After the restoration of the landfill island with mitigation measures fully implemented, the visual impact of the island will be reduced to moderate. Overall visual impacts will be Negative – Low/High. 5 Overall Impact - / - - Overall, landscape and visual impacts will be ‘Negative – Low / High’ for the following reasons: • There are no landscape designations covering the disposal site. • Because it is a marine site, no significant landscape resources will be affected. • The island landfill will significantly affect the open and natural landscape character of the coastline to the south- west of Lamma. • There are reasonably low numbers of residential visual receivers within the visual envelope.
Landfill Gas Assessment
1 Distance between the new O This is a marine site located over 4km west of Lamma Island. / extended landfill and SRs The nearest sensitive receivers are >250m away 2 Number of Receivers O There are no SRs within 500m within 250m (i.e. Consultation Zone) 3 Man-made / Natural O None Pathways for LFG Migration 4 Additional Utilisation of O LFG would be utilised on-site. There are no potential off-site LFG to Reduce GHG users of LFG. Emissions 5 Overall Impact O ‘Neutral’
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Table 11.2: Summary for Lamma Breakwater Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O Neutral Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact + Positive Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - / - - Negative – Low / High Overall Landfill Gas Impact O Neutral
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Table 11.3 Assessment of Significance of Visual Impacts for Lamma Breakwater Island Landfill During Construction / Operation Phase for Lamma Breakwater (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum Nos. of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Construction High) before Mitigation (Insubstantial, and Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR50 Cheung Chau 5km Few Large High Substantial Moderate Occupational VSRs VR54 Lamma Island Power Station 5km Few Intermediate Low Moderate Slight Recreational VSRs VR60 Hung Shing Ye Beach, Lamma 5km Few Large Medium Substantial Moderate Island VR55 Fa Peng Beach, Cheung Chau 5.5km Few Large Medium Substantial Moderate VR60a Lo So Shing Beach, Lamma 5km Few Large Medium Substantial Moderate Island VR57 Lamma Island Trail, Lookout 5km Few Large Medium Substantial Moderate Point pavilion at headland on trail between Hing Shing Yeh Beach and Soh Kwu Wan VR11 Area for Boating, Fishing, 0km - 15km Few Large Medium Substantial Moderate Diving and other water sports (varies) activities Travelling VSRs VR49 Maritime Vessels 2km Moderate Moderate Medium Moderate Slight
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Table 11.4 Assessment of Significance of Visual Impacts for Lamma Breakwater Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Afteruse High) before Mitigation (Insubstantial, and Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR50 Cheung Chau 5km Few Large High Substantial Moderate Occupational VSRs VR54 Lamma Island Power Station 5km Few Intermediate Low Moderate Slight Recreational VSRs VR60 Hung Shing Ye Beach, Lamma 5km Few Intermediate Medium Moderate Slight Island VR55 Fa Peng Beach, Cheung Chau 5.5km Few Intermediate Medium Moderate Slight VR60a Lo So Shing Beach, Lamma 5km Few Intermediate Medium Moderate Slight Island VR57 Lamma Island Trail 5km Few Large Medium Substantial Moderate VR11 Area for Boating, Fishing, 0km - 15km Few Intermediate Medium Moderate Slight Diving and other water sports (varies) activities Travelling VSRs VR49 Maritime Vessels 2km Moderate Small Medium Moderate Slight
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12. EAST TUNG LUNG ISLAND LANDFILL 12.1 Basic Information Project Title 12.1.1 East Tung Lung Island Landfill (ETLIL) – marine site M.7. Nature of Project 12.1.2 The Project would form a new marine based waste disposal site in waters located to the west of Ninepin Group (Figure 12.1). 12.1.3 The ETLIL would involve the construction of an artificial island of approximately 390ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 12.1.4 The ETLIL is located approximately 2.5km to the east of Tung Lung Chau, 2km southeast of the Clear Water Bay Peninsula and some 1km to the west of South Ninepin. Approximately 175Mcum of fill material will be required to construct the artificial island, with a final site formation level to +6mPD. The capacity of the landfill site would be in the order of 65Mcum. 12.1.5 Seabed levels in this area vary from 20 to 30m below Chart Datum. There would be a requirement to dredge some 4Mcum of muds to facilitate seawall construction.
History of Site 12.1.6 The site is located within open marine waters and would be formed entirely as part of this project. The site location coincides with that of the former East Tung Lung Chau (ETLC) Borrow Area that is currently being used as a marine disposal site for uncontaminated muds. Sand dredging at the ETLC Borrow Area was undertaken between the early and mid-1990s 12.1.7 The general environs are of marine conservation value, and the formation of the Shelter Island Marine Park has been proposed, with its southern boundary some 1.5km to the north.
Number and Types of Designated Projects Covered 12.1.8 The ETLIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. 12.2 Outline of Planning and Implementation Programme 12.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 12.2. Assuming landfill operations start in 2018, the ETLIL would be full during the period 2025 to 2030, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 12.2.2 The site is currently not covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 12.2.3 According to the Territorial Development Strategy Review, the area where the site is located is of potentially high recreational value. There are no other identified uses in this area.
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12.2.4 The South East New Territories (SENT) Development Strategy Review focused on conserving the natural environment of the sub-region. The SENT Strategy Review proposed areas for inshore water recreation in the coastal area of Port Shelter, around Kau Sai Chau, Sharp Island and Tai Tau Chau, and between Jin Island and Bluff Island to accommodate the increasing demand for marine activities. To conserve the marine ecology of this area and to maintain its natural setting, a potential Marine Park was identified in Port Shelter, and a potential Marine Conservation Area was identified around the coastline of Tai Long Wan/High Island and Kau Shai Chau, Bluff Island, Basalt Island, Town Island, Wang Chau and Sharp Island. 12.3 Possible Impacts on the Environment 12.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the ETLIL are outlined below. Figure 12.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 12.1 and 12.2.
Air Quality 12.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
12.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site. The closest ASR is the Clear Water Bay Golf and Country Club that is located 2km to the northwest of the site. The site is located in open marine waters with no topographic features situated between the site and the Clear Water Bay peninsula. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 12.3.4 No existing or planned developments that emit similar gaseous emissions are found within 3km from the site boundary. Moreover, there are no existing or planned ASRs in the vicinity of the artificial island. Therefore, cumulative impacts are not anticipated. 12.3.5 Marine vessels will be the mode of transportation for waste delivery to the site. The amount of air pollutants emission from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 300km. As such, the regional impacts are considered to be neutral to minor.
Noise 12.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
12.3.7 No noise sensitive receivers are found within a 300m radius from the boundary of this site. Thus, no significant noise impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated.
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12.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night time periods are not expected to be an issue for this site. 12.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the land filling operations. 12.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicle is not a concern for this site.
Water Quality Baseline Conditions at the Site 12.3.11 The site is located in the Eastern Waters of Hong Kong, between Tung Lung Chau and the Ninepin Group and falls within the Mirs Bay Water Control Zone (WCZ). The generalised current pattern in the area is from west to east / southeast on the ebb tide, with the result that the artificial island site is only very slightly exposed to water quality influence from more westerly waters. On the flood tide the current direction is from the northeast to west / northwest during the dry season, and from the south during the wet season. Apart from the dry season flood tide when the current flows across the site, the current around the site is generally very weak. However, with the weak currents, the arrival of the southwest monsoon (wet season) around late April will have the effect of driving surface waters to the northeast. 12.3.12 There are no routine marine water quality / sediment quality monitoring stations located immediately in the proximity of the artificial island site. However, monitoring data from nearby stations in the Mirs Bay WCZ (MM8 to the south and MM14 to the northeast) and Port Shelter WCZ (PS8 and PS11 to the north) provides an indication of water quality in the area. Sediment data is available from the same two monitoring locations in Mirs Bay (MM8 and MS14 respectively) and from the same location as PS8 in Port Shelter (ref. PS6). 12.3.13 The quality of the marine waters at these three stations is good, with full compliance with the WQO for dissolved oxygen, total inorganic nitrogen (TIN), un-ionised ammonia and E. Coli for each of the past three years.1 Given the current characteristics for the area the water quality at these three locations will reflect that around the artificial island site. The water at routine monitoring locations west of Tung Lung Chau in the Eastern Buffer WCZ also complied with the WQOs established for dissolved oxygen and TIN for the year 2000. 12.3.14 EPD’s routine sediment quality data for the afore-mentioned locations shows no breach of the Lower Chemical Exceedance Level for any of the parameters tested. Excavated sediment from dredging activities would thus be suitable for open sea disposal. Key Issues and Sensitive Receivers 12.3.15 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
1 EPD, Marine Water Quality in Hong Kong for 2000, (EPD 2000)
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12.3.16 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the site. These include:
• Secondary contact recreation subzone (southeast Hong Kong Island and inland waters between southeast Tung Lung Chau and outer Port Shelter); • Gazetted beaches at Shek O and Clear Water Bay; and • Seawater abstraction point at Cape D’Aguilar
12.3.17 In addition, there are a range of aquatic and inter-tidal ecological receivers in the vicinity of the site that may be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the “Ecology” and “Fisheries” subsections. The sensitive receivers include:
• Fish Culture Zones at Tung Lung Chau and Po Toi O; • Cape D’Aguilar Marine Reserve; • Cape D’Aguilar SSSI; • Proposed Marine Park / Reserve at Shelter Island; and • Potential Marine Park / Reserve at Bluff Island and North & South Ninepin; • Potential Marine Park / Reserve at Long Ke Wan and Pak Lap Wan; and • Coral / Green Turtle habitat around the Ninepin Group, Po Toi Islands, Sun Kong Island, Tung Lung Chau and Ching Chau.
12.3.18 The study area also coincides with a broad area of activity for the Black Finless Porpoise, Neophocaena phocaenoides. From sightings data, one of the core areas for this species is east and northeast of Po Toi between June and November, with very uncommon observations of the species closer to the site area during the year. Reclamation and Site Formation 12.3.19 Dredging of some 4Mcum of uncontaminated sediment is proposed for the site development, and there will be reclamation works to create a site footprint of around 390ha. Sediment handling for these activities may give rise to potential water quality impacts from increased suspended solids and reduced dissolved oxygen levels. 12.3.20 The placement of fill for island construction is likely to lead to localised increases in suspended solids levels. The water quality and hydrodynamic modelling indicated that WQO for suspended solids would not be exceeded during the construction of the artificial island but predicted that there would be raised levels of SS at SC5 during Phase 1 construction wet season (17.30%), Phase 2 construction dry and wet seasons (15.34% and 27.80% respectively) and Phase 3 construction wet season (20.88%). Raised levels of SS were also predicted at SC7 (18.19%) during the Phase 2 construction wet season. 12.3.21 During the southwest monsoon there would be a greater potential that the sediment plume would be transported towards the Port Shelter secondary contact recreation subzone and the gazetted beaches at Clear Water Bay, although the water current is generally weak in these waters and is at its strongest from the northeast. This would indicate that the potential for plume dispersal to the north is limited by these forces. Dive surveys during the excavation at the ETLC Borrow Area in 1992 support this scenario, as although the observed extent of the dredging plume was greater during the southwest monsoon (May – June) than the northeast monsoon (March), the area affected was limited to waters immediately around North and South Ninepin islands for both conditions (not reaching as far as East Ninepin islands).2 The sediment plume caused by dredging for the artificial island dredging is not predicted to have significant effects on WSRs to the north.
2 Binnie Consulting Ltd (1995). Underwater Dive Surveys - Volume II: Ninepin Monitoring Update, July 1992.
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Hydrodynamic and Water Quality Impacts Following Island Formation 12.3.22 The water quality and hydrodynamic modelling indicates that the presence of the island would have a minor impact on the flow through the major channels. The most affected is the Tathong Channel where reductions of accumulated flow of 6.72% and 4.57% were predicted in the dry and wet seasons respectively. The modelling also indicated that changes in the flow velocity fields would be small and localised and that overall increases in current magnitude would also be small (1.72% to 1.92%). 12.3.23 In the hydrodynamic and water quality modelling, 39 sensitive receivers that are close to the site were selected for presentation. Of the 39 chosen indicator points, 12 are located in the Port Shelter WCZ (FC6-11, GB7-10, MP7 & SC16), 16 in the Mirs Bay WCZ (FP9, SC5-8, FN1a-d, MP9-11, and SC12-15), 1 in the Eastern Buffer WCZ (FC5) and the remaining 10 in the Southern WCZ (NS6-7, SC3-4, SC11, SC18, MR1, GB6, FP6 & GT2). 12.3.24 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.32 to 7.06mg/L which comply with the WQOs that requires ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO. Compared to the baseline water quality results, the percentage differences of DO levels were minimal with values ranged from -0.31 to 0.46%. 12.3.25 The predicted average dry season salinity ranged from 33.98 to 34.0ppt. Compared with the baseline scenario, the island would cause minimal impacts on salinity levels at all sensitive receivers with maximum percentage differences of 0.03%. The changes in salinity levels were well within the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 12.3.26 The predicted dry season SS levels at the indicator points were in the range of 2.24 to 4.47mg/L. It is predicted that the waste disposal on the site would change the baseline SS levels from -1.95% to 2.54%. The largest percentage increase (2.54%) was predicted at SC7 (Surveyed Corals and Green Turtle site near Ching Chau). Recognising the WQO requirement that the SS levels should not raise the natural ambient level by 30%, all the differences are considered very small. 12.3.27 The predicted average dry season E.coli concentrations (ranged from 1 to 232count/100mL) were well below the WQO of 610cfu/100mL. 12.3.28 The predicted average dry season UIA levels (0.00176 – 0.00348mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L. 12.3.29 The predicted dry season TIN levels for the dry season ranged from 0.0477 to 0.0964mg/L which were below the corresponding WQO for Southern and Port Shelter WCZ (0.1mg/L), for Mirs Bay WCZ (0.3mg/L) and for Eastern Buffer (0.4mg/L). Since the WQO for TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the yearly values. The calculated annual mean was the range from 0.068 to 0.156mg/L. Twelve sensitive receivers (FP6, GT2, MR1, SC3, SC4, SC11, SC18, GB6, GB7, FC6, NS6 and NS7), located in Southern and Port Shelter WCZ, exceeded the WQO of 0.1mg/L. However, the averaged baseline values at these indicator points also exceeded the WQO. The largest percentage increase in the annual mean TIN value was found at GB6 (Shek O Beach) with a value of 2.22%. 12.3.30 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average ranged from 4.27 to 5.46mg/L. and the values complied with the WQOs of ≥4mg/L. The percentage differences ranged from -0.79 to 8.14%. 12.3.31 For 90%ile bottom DO, the values ranged from 2.01 to 5.21mg/L which complied with the WQO of ≥2mg/L. Compared to the baseline water quality results, increases of bottom DO levels were predicted at most of the indicator points with percentage differences ranging from 1.91% to 35.12%.
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12.3.32 The predicted average wet season salinity ranged from 24.78 to 30.13ppt. Compared to the baseline water quality results, the percentage differences in salinity caused by the presence of the island ranged from -0% to 2.08% at the selected indicator points which is lower than the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 12.3.33 The predicted wet season SS levels at the indicator points were in the range of 2.28 to 4.65mg/L. Compared to the baseline scenario, a number of indicator points were identified to have a rise in SS levels with increases that ranged from 0.48% to 16.67%. The largest increase (16.67%) of SS levels was predicted at FC11 (Fish Culture Zone at Tai Tau Chau). These values were regarded as small when compared with the WQO requirement that any waste discharge should not raise the natural ambient level by 30%. 12.3.34 The predicted average wet season E.coli levels caused by the presence of the island ranged from 1 to 130count/100mL, which is well below the WQO of 610cfu/100mL. 12.3.35 The predicted average wet season UIA (0.00332 – 0.00632mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L for the annual mean. 12.3.36 The predicted TIN concentration for the wet season was in the range from 0.0842 to 0.2182mg/L. Compared with baseline levels, the largest increase (3.12%) was predicted at GB6 (Shek O Beach). Since the WQO for TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The results are discussed in Section 12.3.29 above. Cumulative Impacts 12.3.37 The exhausted sand borrow pits at East Tung Lung Chau are currently being used for disposal of uncontaminated muds. An EIA Study for backfilling the exhausted sand borrow pits was endorsed by the EPD in 1998 but does not provide a programme for disposal activities. Despite this, it is possible that fill borrow and disposal activities in the general vicinity of the ETLC (including east of the Ninepin) will continue for some years and thus there is potential for cumulative effects. 12.3.38 The East of Ninepin open sea mud disposal area is located some 5km east of the artificial island location. As of June 2001 this disposal area was still active, reportedly with a remaining disposal capacity of 9.4Mcum. Although only uncontaminated mud is being disposed of at this site, there may be cumulative impacts on the water quality in term of elevated suspended solid level if this project starts before the end of the service life of the East Ninepin Disposal Area. The extent and magnitude of cumulative impacts would be considered further at the detailed EIA stage of the project when further details of the implementation programme are known.
Waste Management / Disposal Impacts 12.3.39 For construction of the artificial island, inert C&D material would be brought in exclusively by marine vessel from a network of barging points in the HKSAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 12.3.40 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 12.3.41 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 175Mcum • Volume of muds be dredged for outer sea wall: 4Mcum
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12.3.42 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 12.3.43 Waste delivery to the site will be by marine vessel and therefore the GHG emission per kg waste handled will be smaller compared to road transport (given the capacity for a marine vessel is 100 times more than a truck). The cumulative distance between marine RTSs and the site is around 300km (extracted from the Preliminary Marine Review (March 2002)). In view of these, the GHG impacts are considered to be neutral to minor.
Ecology Baseline Conditions 12.3.44 The waters around Tung Lung Chau generally mark the limit of influence of the Pearl River flow, and as a result are characterised by high salinity levels (year 2000 mean ~32ppt). These more oceanic conditions and other factors such as the general absence of activities that would otherwise lead to a decline in water quality and low turbidity favour relatively diverse communities, including coral reef ecosystems. 12.3.45 An indication of the character of the benthic invertebrate community immediately east of Tung Lung Chau can be obtained from a review of survey data collected using the belt transect method in August 1993. Dive surveys off the east coast of the island reported molluscs to be abundant in the rocky near-shore community, with rock oysters and mussels equally abundant.3 These are not expected to be present in any great numbers in offshore waters as the substrate is unsuitable (being predominantly silty) and feeding opportunities would be limited. The seabed habitat would likely be dominated by burrowing polychaete worms, with echinoderms and crustaceans also occasionally present. The scavenging gastropod Nassarius siquijorensis was recorded further north at Basalt Island, and polychaetes dominated the benthic infauna in the same area4. 12.3.46 The east coast of Tung Lung Chau was surveyed during the CED’s Underwater Dive Surveys from which was reported a high abundance and diversity of fish, several species of hard coral, soft coral, sponges and an inter-tidal community supporting barnacles, tunicates, anemones and bryozoans. The conservation value of the two east coast sites surveyed was considered “high”.4 A number of dives undertaken along the west coasts of North and South Ninepin and the south coast of Ching Chau for the same study reported a similarly high quality habitat, particularly for hard corals. The artificial island would be located between Tung Lung Chau, Ching Chau and the Ninepin Group and so any deterioration in water quality or change in hydrodynamics brought about by the island landfill may potentially adversely affect these ecological resources. 12.3.47 There are also coral communities further south around Beaufort Island and Sun Kong Island (inc. Fury Rocks) and at the Cape D’Aguilar Marine Reserve. Dive survey reports for several locations report that the conservation value of these site to be “high”. 12.3.48 From AFCD’s public data on the Black Finless Porpoise Neophocaena phocaenoides it is known that this species frequents the waters south of the island, with a core area east of Po Toi through summer and autumn. There have also been very occasional sightings of the Finless Porpoise in the immediate vicinity of the island site (one 1km south of Tung Lung Chau and one 1km west of North Ninepin in spring (March – May)). Locally the Finless Porpoise is protected under the Wild Animals Protection Ordinance (Cap. 170) and is a "Grade II National Key Protected Species” in the Mainland. Internationally the Finless Porpoise is listed as "Insufficiently Known" in the IUCN Red Data Book and is listed in CITES Appendix I (i.e. highest protection).
3 Binnie Consulting Ltd. (1994). Underwater Dive Surveys – Volume II: Marine Ecology of the Ninepins. 4 Binnie Consulting Ltd. (1994). Underwater Dive Surveys – Volume I.
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12.3.49 The Green Turtle Chelonia mydas has been observed in coastal waters around Tung Lung Chau, Ching Chau, around the Ninepin Group of islands and also further afield in the waters off southwest Po Toi. The Green Turtle has the same protection and conservation status as the Finless Porpoise. Direct Habitat Loss 12.3.50 The site footprint covers a surface area of 390ha that corresponds with the minimum area of seabed habitat that would be lost from the works. Associated with this loss there would be smothering and dislocation of benthic species and demersal fishes. As the site is located in waters between 20 and 30m deep there would also be a large loss of water column as a habitat to fisheries and other pelagic species such as the Finless Porpoise and Green Turtle. Water Quality / Hydrodynamics 12.3.51 As the baseline water quality conditions in the area are good, the potential for water quality decline is related to increased suspended sediment / sediment deposition and turbidity during dredging and reclamation works, and the associated potential for decreased dissolved oxygen levels. 12.3.52 The sub-tidal coral communities that surround the island site at East Tung Lung Chau, Ching Chau and throughout the Ninepin Group are prone to sediment transport and deposition from dredging and reclamation activities – particularly the communities along the west coast of North and South Ninepin islands. It is noted that the precursor to the Coastal Ecology Surveys (i.e., Underwater Dive Surveys) commissioned by CED reported significant damage to the coral community on the west coast of North Ninepin following sand dredging at the ETLC Borrow Area. As the artificial island site location more or less overlaps with that of the former ETLC Borrow Area, and as dredging of marine mud will also be required, there is potential for impact on the coral communities at the Ninepin. 12.3.53 The results of the water quality and hydrodynamic modelling exercise predict that the spread of sediment from all three works phases would generally be to the southwest, with only a negligible increase in suspended solids levels (~0.3mg/L on average) at coral communities around the Po Toi group of islands. The model did not predict any significant increase in sediment levels on the coral communities around the Ninepin Group of islands to the east or in waters to the north during either the wet or dry seasons. 12.3.54 The model output does not indicate that there would be any hydrodynamic change or associated water quality decline during operation of the island landfill. Marine Vessel Disturbance 12.3.55 Whilst there have been sightings of the Finless Porpoise in the vicinity of the site, it seems from data available that the area is not part of the core habitat at any time of year. Depending on the direction of marine traffic to the site during its construction and operation however, there is potential for disturbance of the population in the more frequently used waters around Po Toi. Likewise, vessel movement in the area may affect Green Turtles through increased potential for vessel collision and vessel engine noise / vibration.
Fisheries 12.3.56 There are spawning grounds and nursery grounds for commercially important fish in the vicinity of the artificial island location. Spawning grounds exist within the Eastern Waters zone that includes Port Shelter and the marine waters east and southward of Tung Lung Chau, Cape D’Aguilar and Po Toi, and at the South East Hong Kong zone that also includes waters around Po Toi.5 Spawning for most of the commercially valuable fish species is concentrated in the period of June to September.
5 ERM (1998). Fisheries Resources and Fisheries Operations in Hong Kong Waters. For AFCD, Govt. of HKSAR.
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12.3.57 Due to the importance of the fishing in the ETLC area, two key initiatives have been proposed for the area. Under the second phase of the AFCD’s artificial reefs programme a “no take AR deployment area” was proposed at Outer Port Shelter, whilst a working group on fisheries management proposed the establishment of a Fisheries Protection Area at Port Shelter.6 12.3.58 Commercially important fish species in the Eastern Waters zone include: Apogon quadrifasciatus (broadbanded cardinalfish), Parapristipoma trilineatum (chicken grunt), Sebasticus marmoratus (scorpionfish), Trichiurus haumela, Upeneus sulphureus (sulphur goatfish) and U. tragula (freckled goatfish). The waters in the Eastern Waters zone have been recommended for protection under the study. Port Shelter, to the north of the artificial island site, is also an important nursery area for P.trilineatum as well as fry and juveniles of the high value red pargo Chrysophrys major and gold lined seabream Rhabdosargus sarba. Commercially valuable species in the South East Hong Kong zone include Cynoglossus macrolepidotus (tonguefish) and Pseudosciaena crocea (yellow croaker). 12.3.59 Siting the artificial island at this location would thus lead to direct loss of an important spawning area for a range of fish species. Impacts on demersal species such as C.macrolepidotus would be particularly great, whilst any disturbance of the coral reef ecosystem could affect future spawning of fishes. Sediment plumes may be transported south towards coral reef communities at Po Toi, Beaufort Island and Cape D’Aguilar or north of the Ninepin Group on the southwest monsoon, potentially affecting fisheries resources over a large area. 12.3.60 The fish culture zones at Tung Lung Chau and Po Toi O are located approximately 5km to the west and northwest respectively of the artificial island site. Regardless, the model output does not predict any works phase impact upon these fish culture zones.
Cultural Heritage 12.3.61 There is no immediate evidence of archaeological remains in this area. A Custom Station (Declared Monument) was set up at Fat Tong Chau (at the mouth of Tseung Kwan O Bay) during the Song Dynasty (960-1279) to collect taxes from foreign trade ships arriving from South-east Asia. In addition, a fort (Declared Monument) was built in 1717 (Qing Dynasty) on Tung Lung Island located approximately 3km to the west of the site. The Fort was built to control and protect the marine traffic to the mainland, especially from pirates. The fort was abandoned in 1810 when its personnel moved to another fort on the Kowloon Peninsula. The fort is situated on the northeastern side of the island, 35m above the water with cliffs on three sides and commands the approach along the Fat Tong Mun channel. 12.3.62 A late Ming Cannon was found during dredging activities at Joss House Bay directly opposite Tung Lung Island in 1956. 12.3.63 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 12.3.64 Landscape Planning Designations – This area of landscape is located in an Inshore Protection Area as defined by the TDSR Planning designations and the island would have a substantial impact on the intention of this designation. 12.3.65 Landscape Resources - The site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources.
6 AFCD (2001). Fisheries. [http://www.afcd.gov.hk/web/english/fisheries/fish/].
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12.3.66 Landscape Character - The island landfill site falls within the Eastern Coastal Waters Landscape Character Area. The landscape of this part of Hong Kong is expansive open water adjacent to the Clear Water Bay Peninsula, (Figures 12.3 and 12.4). There are no major shipping routes through this area, but a shipping lane is located in the vicinity, and the most notable features are the remote Ninepin Group of islands that is approximately 3km east of the site. The islands are steep-sided, uninhabited and covered only with grass, forming a coastal landscape which is rugged, tranquil and remote. 12.3.67 There exists potential for significant impacts on landscape character resulting from construction works that will introduce new artificial elements incompatible with the existing natural and tranquil landscape character. The predicted impact on landscape character during the construction/operation phase of the project will be substantial. At the end of the construction/operation phase, these impacts are likely to be reduced, as the completed island is restored and the landscape mitigation measures are fully implemented. However, the scale of the island is large and the form and the profile of the island and the coastal edge finishing will be rather artificial in nature. The character of the island is therefore incompatible with the existing natural landscape character. As a consequence, the long-term impact on landscape character will be moderate/substantial. 12.3.68 VSRs – VSRs affected by the island landfill are identified in Tables 12.3 and 12.4. The extent of the project visual envelope is shown in Figure 12.5 and the key views to the island landfill are shown in Figure 12.6. 12.3.69 As the potential island landfill site is approximately 5km from the Clear Water Bay Peninsula, VSRs on the Peninsula will be adversely affected by the imposition of the artificial island. VSRs that will be the most affected are very few land based recreational VSRs that use the area for passive and active recreation. However, the magnitude of impact on them will be small. Other distant recreational VSRs will be affected at Shek O, Siu Sai Wan, and Clear Water Bay. Recreational VSRs using the area for marine recreation will experience substantial or moderate impacts due to their proximity to the island, although their numbers are relatively low. Other VSRs, such as travellers on vessels using the shipping route, are often transient. Overall the island will have a moderate impact during the construction/operation phase, reducing to a slight impact during the afteruse phase.
Landfill Gas 12.3.70 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 12.3.71 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
12.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 12.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to East Tung Lung Chau artificial island site.
Air Quality 12.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
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Noise 12.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5). Water Quality 12.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the artificial island reclamation. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Waste Management 12.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 12.4.6 It is proposed that marine vessel movements to the artificial island avoid the waters east of Po Toi due to the importance of the area as a habitat for the Finless Porpoise. Fisheries 12.4.7 There are no particular measures that are proposed for fisheries resource protection. Cultural Heritage 12.4.8 There are no particular measures that are proposed for protection of cultural heritage resources. Landscape & Visual 12.4.9 Landscape and visual mitigation measures are identified in Part A of the Report and are illustrated in Figure 12.8.
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12.5 Summary 12.5.1 A summary of the SEA for the ETLIL is provided in Tables 12.1 and 12.2: Table 12.1: East Tung Lung Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within 500m of land use the artificial island site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odour would or exacerbate impacts accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant O The site is located in open marine waters to the east of emissions (TSP (construction), Tung Lung Chau, with no known developments that have NOx, CO, SO2 – LFG Flare) relevant emissions within 5km from the site. taking into account ambient conditions 5 Total Emissions of Air Pollutants O / - Waste will be delivered to the site by marine vessel and from the territory-wide waste the cumulative distance to be travelled is estimated to be transportation between the RTSs 300km. and the site 6 Overall Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment
1 Distance to areas of noise O There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the artificial island site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (Only applicable if there are Therefore, this criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O ‘Neutral’
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O As a marine site, no watercourse diversions are required. 2 Potential for sediment O According to EPD’s routine sediment quality monitoring contaminant release data for nearby locations that are representative of the island site, the sediment in the artificial island area is not contaminated. As such, contaminant release is not a key issue. 3 Potential impacts on WSRs - Dredging and reclamation activities would result in the dispersal of sediment towards WSRs in the area but no WQO exceedance would be caused in the construction phases.
It is predicted that TIN standard in the operational phase would be breached, however, it was also breached in the baseline scenario and the elevation due to the presence of island was not significant, therefore, the island would not be the cause of the exceedance. Therefore, the water quality impact is minor. 4 Potential Impacts on O Marine site – no groundwater issues. Groundwater 5 Potential Cumulative Impacts - The exhausted sand borrow area at East Tung Lung (Potential for concurrent projects Chau is currently being used for controlled marine mud to exacerbate preceding disposal. Due to the proximity of the sites it is assumed impacts) that this activity would be complete before any works for the artificial island were undertaken.
The East Ninepin Marine Disposal Area (open water) to the east of the artificial island site is currently in operation. Subject to operational details for this disposal area there may be potential for concurrent works that may give rise to cumulative impacts from sediment plume formation.
The extent and magnitude of cumulative impacts would be considered further at the detailed EIA stage of the project. 6 Overall Impact - WSRs in the area that may be impacted are the corals and Green Turtle site at Tung Lung Chau. Impacts on other WSRs are not anticipated due to the hydrodynamics of the area. There is also some potential for cumulative effects from fill management works that have been and are currently active in the area. As the potentially affected WSRs are relatively isolated, the potential for adverse water quality impacts is considered ‘Negative – Low’.
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Impacts Score Commentary
Waste Management Assessment 1 Balance of Materials + The site could accommodate major volume of public fill (surplus/deficit of public fill (175Mcum) negating the need to import filling material for needed for landfill development) site formation. Dredged muds will be incorporated with the fill materials within the island footprint. 2 GHG emissions from mode of O / - Waste will be delivered to the site via marine vessel. The transport for delivery of waste to distance travelled from marine RTS(s) to the site has the site from RTSs been estimated to be 300km. 3 Overall Waste Impact O ‘Neutral’ Ecological Assessment 1 Potential for secondary - The model does not predict that the works phase will give environmental impacts on “Areas rise to any significant impact upon the Cape D’Aguilar of Absolute Exclusion” Marine Reserve and SSSI or upon the proposed Shelter Island Marine Park / Reserve to the north. However, the hydrodynamics in the area are complex and although significant impacts are not anticipated, there is still potential that the sediment levels in the vicinity of these receivers may be come elevated. 2 Affects an important habitat - - The coral reef habitats in the coastal waters at East Tung Lung Chau and possibly to the south around the Po Toi group of islands may be affected by elevated sediment levels.
The open waters around the artificial island site are a habitat to fisheries spawning grounds of ecological importance (i.e., many coral reef species). There have also been a number of sightings of the Finless Porpoise to the south and the Green Turtle to the north of the site. 3 Affects a species of conservation - / - - All hard (stony) corals are protected in the HKSAR under importance the Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187). These include many coral species found around the study area. The fish and benthic communities associated with the reefs are also of conservation importance as they are integral to functioning of a healthy reef ecosystem.
Beyond the immediate site area, both the Finless Porpoise and the Green Turtle have been observed. Both species are protected under local and international conservation laws: WAPO, Cap. 170 and CITES Appendix I. The Finless Porpoise is also a Grade II protected species in the Mainland. These species migrate over a wide area and would be prone to direct impact from vessel disturbance / collision and from loss of habitat and possibly feeding / breeding grounds. 4 Potential for Cumulative - Any concurrent mud disposal activity at the exhausted Ecological impacts on sites of sand borrow area at East Tung Lung Chau or the East recognised value Ninepin Marine Disposal Area may give rise to cumulative impacts on coral communities from sediment plume formation. Likewise with other fill management works that may take place in the area. 5 Overall Ecological Impact - - Although modelling does not predict significant water quality decline associated with the works, the presence of protected areas of conservation importance, ecologically valuable coral reef habitat and associated species of conservation importance all around the potential site means the overall impact potential is ‘Negative – High’.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary - The fish culture zones at Tung Lung Chau and Po Toi O environmental impacts on “Areas and the proposed “Fisheries Protection Area” and “no of Absolute Exclusion” take artificial reefs deployment area” proposed at Port Shelter are not predicted to be affected by the works. 2 Affects an important mariculture - / - - The island area is within an important spawning ground / fisheries resources (including for a number of commercially valuable fish species. This spawning / nursery ground) zone includes waters south and east of the site area and so may be subject to a series of effects. The waters at Port Shelter to the north form an important nursery area and although they would not be directly affected, there is potential for secondary and other effects on fisheries resources. 3 Potential for Cumulative - As with ecology, there would be potential for adverse Fisheries Impacts on sites of cumulative impacts (sediment induced) should recognised value concurrent fill management marine works be in progress. 4 Overall Impact - The immediate site area is of fisheries significance as a spawning ground, whilst the Port Shelter area to the north is also a nursery ground where fisheries protection measures including a FPA and artificial reef have been proposed. Despite this, the modelling exercise indicates that there is limited potential for adverse impact upon fisheries resources at Port Shelter. Therefore, overall: ‘Negative – Low’. Cultural Heritage Assessment
1 Important cultural (Declared, O The nearest designated site is a Declared Monument, Deemed or Graded sites) / (Fort) located on Tung Lung Chau, 3km from the site. archaeological sites The Fort is located high on the island, and would not be affected by the development of ETLIL. 2 Potential for archaeological - The site is located in the vicinity of land based value archaeological sites with links to maritime activities. Recognising the lack of archaeological data currently available at the site, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land Heritage Impacts on sites of based, (on Tung Lung Chau (3km), therefore they would recognised value not be affected by this development. There are no planned or confirmed projects, which may cause cumulative heritage impacts. 4 Overall Impact - The potential impacts on cultural heritage are considered to be ‘Negative – Low’. Whilst there is not direct evidence of cultural heritage remains in the site area, the occurrence of remains on adjacent land increases the potential for marine archaeological finds.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape - - This area of seascape is located in an Inshore Water Planning and Designations Protection Area and will have a substantial impact on the planning intention for this area. Overall impacts will therefore be High. 2 Impacts on Landscape O As the site lies in a marine area, there will be no Resources significant impacts on landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - - Construction and operation of the island will be Character incompatible with the open and natural and tranquil landscape qualities of the area. Once completed, the afteruse mitigation will reduce the overall impact of the island a little. However, the landfill will still be incompatible with existing landscape character and resulting overall impacts will be Negative – High. 4 Visual Impacts - / - - The number of VSRs affected by the site will be relatively low, but those affected have a high visual amenity resulting, from the strong natural character of the area. The most affected VSRs are a number of recreational VSRs that use the area for passive and active recreation. Generally therefore, visual impacts will be Negative – Low/High. 5 Overall Impact - - Overall, landscape and visual impacts will be ‘Negative – High’ for the following reasons: • The Inshore Water Protection Area will be impacted upon. • No significant landscape resources are affected; • The open, natural and isolated landscape character of the Eastern Coastal Waters and the Ninepin will be substantially compromised; • There are low numbers of residential VSRs within the visual envelope of the site and a very small number close to it.
Landfill Gas Assessment 1 Distance between the new / O The nearest sensitive receivers are >250m from the site. extended landfill and SRs 2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. the LFG Consultation Zone) 3 Man Made Pathways for LFG O None. Migration 4 Natural (e.g. Geological) O None. Pathways for LFG Migration 5 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce Greenhouse Gas use) Emissions 6 Overall Landfill Gas Impact O ‘Neutral’
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Table 12.2 Summary of East Tung Lung Island Landfill SEA
Overall Impacts Score Commentary Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - - Negative – High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - - Negative – High Overall Landfill Gas Impact O Neutral
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Table 12.3 Assessment of Significance of Visual Impacts for East Tung Lung Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Construction / Medium, High) before Mitigation (Insubstantial, and Source(s) only) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential Receivers VR92 Siu Sai Wan 8km Many Intermediate High Moderate to Moderate Substantial Recreational Receivers VR68 Shek O 9km Many Intermediate Medium Moderate Slight VR69 Clear Water Bay 5km Many Large Medium Substantial to Moderate Moderate VR69a Clearwater Bay Golf Course 2.7km Few Large Medium Substantial to Moderate to Moderate Substantial VR71 Leung Shuen Wan Chau (High 12km Very Few Small Medium Moderate to Slight Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 10km Few Intermediate Medium Substantial Substantial to Diving and other Water sports (Varies) Moderate activities Travelling Receivers VR49 On Vessels using the Shipping 0.5 – 10km Very Few Intermediate Low Slight to Moderate Slight Lanes (Varies)
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Table 12.4 Assessment of Significance of Visual Impacts for East Tung Lung Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Afteruse Medium, High) before Mitigation (Insubstantial, and Source(s) only) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential Receivers VR92 Siu Sai Wan 8km Many Intermediate High Moderate to Slight to Substantial Insubstantial Recreational Receivers VR68 Shek O 9km Many Intermediate Medium Moderate Slight to Insubstantial VR69 Clear Water Bay 5km Many Large Medium Substantial to Slight to Moderate Insubstantial VR69a Clearwater Bay Golf Course 2.7km Few Large Medium Substantial to Moderate to Slight Moderate VR71 Leung Shuen Wan Chau (High 12km Very Few Small Medium Moderate to Slight Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 10km Few Intermediate Medium Substantial to Moderate Diving and other Water sports (Varies) Moderate activities Travelling Receivers VR49 On Vessels using the Shipping 0.5 – 10km Very Few Intermediate Low Slight to Moderate Insubstantial Lanes (Varies)
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13. EASTERN WATERS ISLAND LANDFILL 13.1 Basic Information Project Title 13.1.1 Eastern Waters Island Landfill (EWIL) – marine site M.8. Nature of Project 13.1.2 The Project would form a new marine based waste disposal site in the remote Eastern Waters of Hong Kong (Figure 13.1). 13.1.3 The EWIL would require construction of an artificial island of approximately 875ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. 13.1.4 Construction works would be as described in Part A, Section 3.2. In addition works for the EWIL would include: - Dredging of about 25Mcum of underlying muds for construction of an outer seawall.
Location and Scale of Project 13.1.5 The EWIL is located adjacent to the eastern boundary of SAR waters. It is 17km east of the Clear Water Bay Peninsula and 11km east of both Basalt Island and the Ninepin Group of Islands. Seabed levels in this area are approximately 25m below Chart Datum, except for Victor Rock, an isolated underwater pinnacle formation consisting of a number of outcrops at a depth of about -10mPD. Victor Rock is approximately 3km to the northwest of the site. 13.1.6 The EWIL would cover an area of 875ha to an elevation of +6 mPD. The artificial island would accommodate a landfill with a capacity of 140Mcum to an elevation of +56mPD. The site would accommodate approximately 400Mcum of fill material.
History of Site 13.1.7 The site is located within open marine waters and is to be formed entirely as part of this project. There has been no previous development activity within the site area.
Number and Types of Designated Projects Covered 13.1.8 The EWIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1.
13.2 Outline Of Planning and Implementation Programme 13.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 13.2. Assuming landfill operations start in 2022, EWIL would be full during the period 2040 to 2050, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 13.2.2 The site is currently not covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 13.2.3 According to the Territorial Development Strategy Review, the area where the site is located is of potentially high recreational value. There are no other identified uses in this area. 13.2.4 The South East New Territories (SENT) Development Strategy Review focused on conserving the natural environment of the sub-region. The SENT Strategy Review proposed areas for inshore water recreation marine park and marine conservation areas in the coastal areas of Port Shelter.
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13.3 Possible Impacts on the Environment 13.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the EWIL are outlined below. Figure 13.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 13.1 and 13.2.
Air Quality 13.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts:
• Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
13.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 13.3.4 The site lies in an open marine area, with no known developments (existing or planned) within 5km of the site boundary. The build-up of air pollutants is not anticipated. 13.3.5 Marine vessels will be the mode of transportation for waste delivery to the site. The amount of air pollutants resulting from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 410km. Given the likely distance to be travelled, the regional impacts from waste transportation may be moderate.
Noise 13.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
13.3.7 No noise sensitive receivers are found within a 300m radius from the boundary of this site. Thus, no significant noise impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 13.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue for this site. 13.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the land filling operations.
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13.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicle is not a concern for this site.
Water Quality Baseline Conditions at the Site
13.3.11 The site is located within the Mirs Bay Water Control Zone (WCZ). The site is located at some distance offshore and is predominantly influenced by oceanic currents which flow to the south west in the winter and north east in the summer. Background water quality conditions have been established from EPD routine water quality monitoring stations, the latest available data being that collected in 2000, (EPD 2001). Locations of the nearest water quality monitoring stations (MM14 and MM15) are presented in Figure 13.1. 13.3.12 Water quality data for 2000 at the monitored stations indicates full compliance with the Mirs Bay WCZ Water Quality Objectives (WQOs) for key parameters such as dissolved oxygen, (DO), E. Coli, total inorganic nitrogen (TIN) and un-ionised ammonia. 13.3.13 The nearest regular EPD sediment monitoring station in this area is MS14, which lies approximately 1.3km to the southwest. Sediments at MS14 are considered to be uncontaminated according to EPD data. The potential for impacts associated with contaminated marine muds is considered to be limited. Key Issues and Sensitive Receivers 13.3.14 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
13.3.15 There are no Water Sensitive Receivers (WSRs) in the immediate vicinity of the site. The nearest WSRs are:
• Gazetted beach at Clear Water Bay First (18km); and • Gazetted beach at Clear Water Bay Second (18km).
13.3.16 In addition, there are a number of ecological resources around the site that may be sensitive to any decline or change in water quality or sediment deposition / erosion patterns. Potential impacts upon these are discussed in the “Ecology” subsection. These receivers include:
• Corals and associated marine fauna at Victor Rock (3km); • Corals at the Ninepin Group (11km); • Bluff Island and Basalt Island SSSI; • Potential Marine Park / Reserve at Bluff Island and North & South Ninepin; • Potential Marine Park / Reserve at Long Ke Wan and Pak Lap Wan; • Potential Marine Park / Reserve at Tai Long Wan; • Occasional Finless Porpoise; • Fisheries protection area at Clear Water Bay (9km); and • Marine Reserve at Cape D’Aguilar (16km).
13.3.17 The locations and uses of the WSRs are shown in Figure 13.1.
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Reclamation and Site Formation
13.3.18 The placement of fill for island construction may lead to localised increases in suspended solids levels. The water quality and hydrodynamic modelling indicated that the impacts of the island construction on SS were fairly small, and that no the predicted levels would not approach or exceed WQO. The highest SS level increase is predicted to occur at SC14 (12.75%) during the Phase 2 construction wet season. Hydrodynamic and Water Quality Impacts Following Island Formation 13.3.19 The water quality and hydrodynamic modelling indicated that the presence of the artificial island would have minimal impacts on the accumulated flows through major channels, with the largest impact occurring in the Tathong Channel in the dry season, where a 1.49% increase is predicted. The modelling also indicated that the changes in the flow velocity fields would be small and localised. The predicted overall change in current magnitude is predicted to be 3.3% to the northeast and 16.3% to the southwest of the island. 13.3.20 For the hydrodynamic and water quality modelling, 46 sensitive receivers that are close to the site were selected for presentation. Of the 46 chosen indicator points, 12 are located in the Port Shelter WCZ (FC6-11, GB7-10, MP7 & SC16), 22 in the Mirs Bay WCZ (FP9, SC5-8, FN1a-d, MP4, 8-11, 8b, GT3 and SC12-14, 15, 17, 21), 1 in the Eastern Buffer WCZ (FC5), 1 in the Mainland waters (MF) and the remaining 10 in the Southern WCZ (NS6-7, SC3-4, 11, MR1, GB6, FP6, SC18 and GT2). 13.3.21 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 5.89 to 7.10mg/L which comply with the WQOs of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO as well as the Mainland sea water quality standard of >5mg/L. Compared to the baseline water quality results, the largest percentage decrease in DO caused by the presence of the island would be less than 4% which were predicted at FC7 (Ma Nam Wat Fish Culture Zone and Trio Beach). 13.3.22 The predicted average salinity in the dry season ranged from 33.96 to 34.00ppt. The differences in salinity levels caused by the presence of the island would be minimal (less than 0.05%) at all the selected indicator points as compared to the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 13.3.23 The predicted dry season SS levels at the indicator points were in the range of 1.59 to 4.47mg/L. It is predicted that the waste disposal on the island would increase the SS levels at some of the sensitive receivers with the largest differences of 6.65%, 6.88%, 12.50% and 8.16% predicted at Station MP8b (Tai Long Wan), FC10 (Kai Lung Wan fish culture zone), FC11, (Tai Tau Chau fish culture zone) and GT3 (Green Turtle site near Port Island) respectively. Comparing to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, these differences are still considered small. 13.3.24 The predicted average dry season E.coli levels ranged from 1 to 45count/100mL which were well within the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. 13.3.25 The predicted average dry season UIA (0.00170 – 0.00349mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L as well as the Mainland standard of 0.02mg/L.
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13.3.26 The dry season TIN levels ranged from 0.0456 to 0.0949mg/L and below the annual mean WQO for TIN of 0.1mg/L for both the Southern WCZ and Port Shelter WCZ and 0.3 and 0.4mg/L for the Mirs Bay WCZ and Eastern Buffer WCZ respectively. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. As a result, exceedances were found at SC3, SC4, SC11, SC16, SC18, GB6 and 7, FP6, GT2, MR1, NS6 and 7 and FC6 (ranged from 0.10 to 0.15mg/L). However, the averaged baseline values (0.10 to 0.15mg/L) at these 13 stations also exceeded the WQO. All these stations are located in Port Shelter WCZ and Southern WCZ with an annual mean WQO of 0.1mg/L. The predicted values at the remaining stations complied with their respective WQOs. The TIN results for the Mainland station (MF) also complied with the Mainland standard of 0.3mg/L for both the dry and wet season. 13.3.27 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average ranged from 3.99 to 5.46mg/L and the values complied with the WQOs of ≥4mg/L except for GB9 and FC7. The 90%ile DO of 3.99mg/L was predicted at both GB9 and FC7 which breached the WQO with a percentage difference of 0.25% and –6.34% as compared to the baseline values of 3.98 and 4.26mg/L respectively. At other stations where there was a decrease in 90%ile DO levels, the percentage reduction were all below 3.0%. The DO results for MF (4.79mg/L) also breached the Mainland standard of 5mg/L. 13.3.28 For 90%ile bottom DO, the values ranged from 1.44 to 5.17mg/L. Only FC8 (Fish Culture Zone at Kau Sai) with value of 1.44mg/L breached the WQO of ≥2mg/L for bottom DO level. However, the baseline values of FC8 also breached the WQO. 13.3.29 The predicted average wet season salinity ranged from 24.98 to 31.22ppt. Comparing to the baseline water quality results, the percentage differences in salinity caused by the presence of the island were small (less than 3%) at all the selected indicator points as compared to the WQO requirement that change due to any waste discharge should not exceed 10% of natural ambient level. 13.3.30 The predicted wet season SS levels at the indicator points were in the range of 1.62 to 4.57mg/L. It is predicted that the island would increase the SS levels at most of the sensitive receivers with the largest differences of 6.78%, 8.24%, 8.96%, and 18.70% predicted at Station SC11 (Po Toi Island surveyed corals), GB10 (Silverstrand Beach), GB9 (gazetted beach at Hebe Haven) and FC7 (Fish Culture Zone at Ma Nam Wat) respectively. Compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, these differences are still considered acceptable. 13.3.31 The predicted average wet season E.coli levels ranged from 1 to 32count/100mL and well below the WQO of 610cfu/100mL and the Mainland standard of 200count/100mL. 13.3.32 The predicted average wet season UIA (0.00310 – 0.00709mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L for annual mean and the Mainland standard of 0.02mg/L. The largest percentage increase caused by the island as compared with the baseline scenario was at GB9 (gazetted beach at Hebe Haven) and FC7 (Fish Culture Zone at Ma Nam Wat) with values of 7.91% and 7.59% respectively. 13.3.33 For the predicted wet season TIN levels, the values were quite high and ranged from 0.0685 – 0.2163mg/L. The largest two levels were at GT2 (Green Turtle site at Po Toi) and SC3 (surveyed corals near Beaufort Island) with values of 0.2163 and 0.2093mg/L respectively. Compliance of the predicted values with the annual mean WQO for TIN is discussed in Section 13.3.26.
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Cumulative Impacts 13.3.34 A proposed submarine gas pipeline connecting the Liquefied Natural Gas Receiving Terminal (GRT) at Cheng Tou Jiao in China to the Power Station at Lamma Island is currently under examination. The overall feasibility and preferred alignment has not been confirmed. If the project proceeds, the alignment is likely to run in close proximity to the EWIL site. It is assumed that construction would be completed before works on an island landfill. However, if construction works for these two projects were to be undertaken concurrently, there would likely be cumulative water quality impacts, in particular the localised increased in suspended solids and associated impacts. 13.3.35 The open sea mud disposal areas at East of Ninepin and East Tung Lung Chau are currently being used for disposal of uncontaminated muds. These are discussed further in Chapter 12 (East Tung Lung Island Landfill). Although only uncontaminated mud is being disposed of at these sites, there may be cumulative impacts on the water quality in term of elevated suspended solid level if the EWIL starts before the end of the service life of the disposal areas. 13.3.36 The extent and magnitude of cumulative impacts would be considered further at the detailed EIA stage of the project when further details of the implementation programmes are known.
Waste Management / Disposal Impacts 13.3.37 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 13.3.38 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 13.3.39 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 400Mcum • Volume of muds be dredged for outer sea wall: 25Mcum
13.3.40 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 13.3.41 Regarding the GHG emissions, waste delivery to the site will be by marine vessel which will have a lower GHG emission per kg waste handled than road transport given the fact that its capacity is almost 100 times larger than a truck. However, the cumulative distance between marine RTSs and the site is around 410km (referred to Preliminary Marine Review (March 2002)), the impacts associated with GHG emissions is considered to be moderate.
Ecology Baseline Conditions 13.3.42 Due to the remoteness of the site, there are relatively few ecological resources of recognised conservation interest in the near vicinity of the EWIL. However there are sites of high ecological value closer to the Sai Kung and Clear Water Bay Peninsulas.
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13.3.43 The isolated islands and submerged rocks of the Eastern Waters support some of the most diverse and locally important coral habitats in Hong Kong (ERM 1998a)1. This includes the coral habitats found at the Ninepin Group of islands and Basalt Island (both about 11km west of the EWIL) as well as Victor Rock, the submerged rocky pinnacle about 3km north west of the site. These sites are characterised by diverse communities of hard and soft coral, gorgonians, sponges, holothurians, sea urchins, sea fans and fish species. The Bluff Island and Basalt Island SSSI (11km to the west) has been designated primarily due to its unique grassland community, however, the value of rocky shore communities on both islands is graded as high. In addition, a study is currently being carried out by Hong Kong Institute of Education2 to determine the suitability of the area around Sai Kung Peninsula (Bluff Island to Tai long Wan) for designation as a Marine Park or Marine Reserve. 13.3.44 Underwater dive surveys of Victor Rock and East Ninepin (Shue Long Chau) indicated a high diversity and abundance of marine ecology at Victor Rock and a medium to high diversity and abundance of marine ecology at East Ninepin. Both sites were noted as having a “high conservation value” (Binnie, 1995c)3. Six major types of corals including all hard (stony) corals are protected in the HKSAR under the Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187). 13.3.45 The benthic habitat in the general area of the EWIL, is characteristic of soft sediments, regular trawling in the area has resulted in a uniformly disturbed habitat. Grab samples taken at the East of Ninepin disposal ground showed that the recolonised dumped material was distinct from surrounding reference stations, being dominated by spionid polychaetes with an overall lower diversity (ERM 1997d 4 ). The surveyed areas were categorised as being “moderately disturbed”. 13.3.46 According to recent cetacean survey data, the site is outside of the range of Chinese White Dolphin and there is a low density of sightings of Finless Porpoise, the core area of which is around Ha Mei Tsui at the south west of Lamma Island. Direct Habitat Loss 13.3.47 The site footprint covers a surface area of 875ha. As result of the disturbance due to extensive trawling in the area, it is anticipated that there will be no benthic species of particular ecological interest in the area and loss of this habitat is unlikely to be significant. Water Quality / Hydrodynamics 13.3.48 Dredging and reclamation activities may result in noise disturbance and changes in water quality, which in turn may drive the Finless Porpoise out of the area. Any deterioration in water quality would also drive fish from the area due to their sensitivity to increased suspended sediment levels, resulting in reduced feeding opportunities for the Finless Porpoise. However as this is not a core habitat for this species, impacts are anticipated to be acceptable.
1 ERM-Hong Kong Ltd (1998A) Environmental Impact Assessment, of Backfilling marine Borrow Areas at East of Tung Lung Chau. Civil Engineering Department, Hong Kong Government
2 Hong Kong Institute of Education. Study on the suitability of Tai Long Wan Area as marine park or marine reserve Hong Kong Institute of Education. Study on the suitability of Long Ke Wan and East High Island Dam, Pak Lap Tsai and Pak Lap as marine park or marine reserve. Hong Kong Institute of Education. Study on the suitability of Bluff Island, North and South Ninepin as marine park or marine reserve.
3 Binnie Consultants Limited (1995c) Fill Management Study - Phase IV Investigation and Development of Marine Borrow Areas: Marine Ecology of Hong Kong: Report on Underwater Dive Surveys Oct 1991 – Nov 1994 Vol I. Civil Engineering Department, Hong Kong Government.
4 ERM-Hong Kong Ltd (1997d) Seabed Ecology Studies: East of Ninepins Final Report, Civil Engineering Department, Hong Kong Government.
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13.3.49 There is potential for adverse water quality impact on sub-tidal coral communities, from sediment deposition and increased turbidity that may affect photosynthetic activity of this diverse and ecologically fragile community. The results of the water quality / hydrodynamic modelling exercise show that levels of suspended solids at various sensitive receivers in Inner Eastern Waters would be above background concentrations to the order of around 5mg/L. Taking a precautionary approach, such an increase may adversely affect the sub-tidal coral and associated benthic community. 13.3.50 Given its closer proximity to the site, the ecologically sensitive Victor Rock coral habitat (SC14) is potentially more at risk from the effects of sediment disturbance / transport and the effects of any increase in other water quality parameters. This location represents the worst-case scenario for all ecologically sensitive receivers modelled in the area. 13.3.51 During the construction phase, the model output shows that suspended sediment levels in the vicinity of the coral community at Victor Rock (SC14) during the wet season Phase 1 works (i.e., initial filling of the water column) increase by 10.55% above the baseline level. This is equivalent to a mean daily sedimentation rate of 2.2 g/m2 that, depending on the actual deposition area, could potentially generate give rise to an adverse impact on the coral community. Likewise, during the Phase 2 construction wet season there is a predicted increase over the baseline of 4.3 g/m2/day; with sedimentation from Phase 3 construction wet season predicted to be 2.3 g/m2/day. 13.3.52 The worst-case dry season scenario would be a predicted mean sedimentation rate of 0.2 g/m2/day; insignificant when compared with the sedimentation limit of 100 g/m2/day. 13.3.53 Following construction of the EWIL, the island site may result in changes to the hydrodynamics of the area, including slightly increased velocities in the north south direction between the island and the Sai Kung Peninsula, with a possible reduction in circulation within Inner Port Shelter. Any minor increase in flow velocities would benefit filter-feeding opportunities for the coral and the benthic communities around the Ninepin and Basalt Island. Any reduction in flows within Port Shelter would likely reduce the flushing capacity of these sheltered waters with a consequent negative impact upon fish fry and capture fisheries. 13.3.54 With respect to the effect on hydrodynamics from the operational EWIL, as predicted by the numerical model, there is no significant change in the flux of water at two key assessment points in the vicinity of the EWIL. From this it can be confirmed that no significant hydrodynamic effects would arise. 13.3.55 As regards potential changes in water quality induced by hydrological change, there would be no significant change. Model output data in the vicinity of Victor Rock shows no significant change in concentrations of key parameters during the wet season (i.e., worst-case scenario). The greatest percentage change is predicted for Total Inorganic Nitrogen (TIN) with a 1.24% increase (to 0.122mg/L). A decline in salinity at Victor Rock of 1%, or 0.3ppt is also predicted. As such, there would be no negative impacts upon the coral communities in the vicinity. 13.3.56 The worst-case increase in suspended sediment levels at the coral communities closest to the potential EWIL is 0.07mg/L at SC13 (coral near Pak Lap Wan) during the dry season, and an increase of 0.08mg/L at SC8 (coral near Basalt Island) during the wet season. The increase under both of these scenarios is negligible and of no impact potential to the coral communities. Marine Vessel Disturbance 13.3.57 It is known from data on strandings of Finless Porpoise specimens that vessel collision is a significant cause of death (Jefferson, 2001). Whilst the area is not a core area for the species, the increase in marine traffic required for site formation and landfill operations could lead to an increase in incidences of vessel collision.
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Fisheries 13.3.58 The fisheries of the sites located in the Eastern Waters, (M8, M9 and M10) are generally of low significance compared to other fishing areas in Hong Kong waters. The Eastern Waters as a whole are productive, but this productivity tends to be restricted to inland areas. Trawl catches at Ninepin, Basalt Island waters are characterised by high biomass of commercially valuable Grouper, Yellow Croaker and Pomfret species. Purse seine vessels are based mainly in ports in the Eastern Waters of Hong Kong and concentrate their activity there. Less than 7% of their time is spent fishing outside Hong Kong waters and their catches contribute the largest portion of the entire fishing fleets catch from Hong Kong waters, (ERM 19985). 13.3.59 Port Shelter is recognised as a nursery area for commercial fish species and it also includes a number of fish culture zones. In addition, the Artificial Reef Deployment Study (ERM 1999a6 has identified an area adjacent to Basalt Island as being suitable for construction of an artificial reef. Due to the importance of the fisheries in the Port Shelter area, two key initiatives have been proposed for the area. Under the second phase of the AFCD’s artificial reefs programme a “no take AR deployment area” was proposed at Outer Port Shelter, whilst a working group on fisheries management proposed the establishment of a Fisheries Protection Area at Port Shelter7. 13.3.60 As noted above, the presence of the island site may result in minor changes to flow patterns in and around Port Shelter, possible affecting the fisheries resources in this relatively sheltered bay. However, effects are anticipated to be minimal. Marine dredging works will have potential to affect fisheries in the area; again impacts are not anticipated to be significant. Overall, the potential impact of constructing the EWIL upon fisheries resources is considered limited primarily due to it remoteness to areas of high fisheries value.
Cultural Heritage 13.3.61 This site is located some distance offshore. There is no immediate evidence of archaeological remains in this area or in the near vicinity. The nearest sites of known archaeological interest are located at the Sai Kung Peninsula. In addition, an historic shipwreck was found in the waters now occupied by High Island Reservoir (formerly known as Kwun Mun Channel) in 1974. The shipwreck, dating to late Song-early Ming Dynasties, was found during the construction of the High Island Water Scheme. Together with the shipwreck, some pottery and porcelain shards and glass beads of Indian origin were also recovered. 13.3.62 Given the remoteness of this site from known land based sites of cultural heritage interest, the likelihood of archaeological remains in this area appears limited. However, given the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 13.3.63 Landscape Planning Designations – This area of seascape is not covered by any planning designations reflecting landscape values and so there will be no impact on these values. 13.3.64 Landscape Resources - The site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources.
5 ERM-Hong Kong Ltd (1998) Fisheries Resources and Fishing Operations in Hong Kong Waters, Agriculture & Fisheries Department, Hong Kong Government.
6 ERM-Hong Kong Ltd (1999a) Artificial Reef Deployment Study: Technical Paper 3 – Site Selection, Agriculture & Fisheries Department, Hong Kong Government.
7 AFCD (2001). Fisheries. [http://www.afcd.gov.hk/web/english/fisheries/fish/].
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13.3.65 Landscape Character - The island landfill site falls within the Eastern Coastal Waters Landscape Character Area. The seascape of this part of Hong Kong is an expansive area of open water to the East of Clear Water Bay Peninsula, lying on the edge of the boundary of the HKSAR waters (Figures 13.3 and 13.4). There are no major shipping channels in the vicinity of EWIL and the most notable features are the remote Ninepin Group of islands that is approximately 10km west of the site. The islands are steep-sided, uninhabited and covered only with grass and form a coastal landscape character which is rugged and remote. 13.3.66 There exists potential for significant impacts on landscape character resulting from construction works that will introduce new artificial elements incompatible with the existing natural and tranquil landscape character. The predicted impact on landscape character during the construction/operation phase of the project will be substantial. At the end of the construction/operation phase, these impacts are likely to be reduced, as the completed island is restored and the landscape mitigation measures are fully implemented. However, the scale of the island is large and the form and the profile of the island and the coastal edge finishing will be rather artificial in nature. The character of the proposed island is therefore incompatible with the existing natural landscape character. As a consequence, the long-term impact on landscape character will be moderate/substantial. 13.3.67 VSRs – VSRs affected by the island landfill are identified in Tables 13.3 and 13.4. The extent of the project visual envelope is shown in Figure 13.5 and the key views to the island landfill are shown in Figure 13.6. 13.3.68 As the island landfill site is approximately 16km from the Clear Water Bay Peninsula, there are no VSRs close to the site. VSRs that will be the most affected are very few recreational receivers that use the area for passive and active recreation. However, the magnitude of impact on them will be small. Other distant recreational VSRs will be affected at Shek O, Clear Water Bay, Tai Wan Beach of Tai Long Wan/Maclehose Trail, Leung Shuen Chau. Other receivers, such as travellers on vessels using the shipping route, are often transient. Generally, all VSRs are far away from the site, and the residual visual impact during the construction/operation and afteruse phase will be insubstantial. 13.3.69 Mitigation Measures – Landscape and visual mitigation measures are identified in Part A of the Report and are illustrated in Figure 13.8.
Landfill Gas 13.3.70 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 13.3.71 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
13.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 13.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to EWIL.
Air Quality 13.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
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Noise 13.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 13.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the artificial island reclamation. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Waste Management / Disposal Impacts 13.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 13.4.6 No specific mitigation measures to protect ecological resources are recommended at this stage, other than good site practice as described in Part A (Section 5).
Fisheries 13.4.7 There are no particular measures that are proposed for fisheries resource protection. Cultural Heritage 13.4.8 There are no particular measures that are proposed for protection of cultural heritage resources.
Landscape & Visual 13.4.9 Landscape and visual mitigation measures are identified in Part A of the Report and are illustrated in Figure 13.8.
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13.5 Summary 13.5.1 A summary of the SEA for the EWIL is shown in Tables 13.1 and 13.2:
Table 13.1: Evaluation Summary for Eastern Waters Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within land use 500m of the artificial island site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours or exacerbate impacts would accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant O The site is located in open marine waters to the emissions (TSP (construction), southern HKSAR waters fringe, with no known NOx, CO, SO2 – LFG Flare) developments that have relevant emissions within 5km taking into account ambient from the site. conditions 5 Total Emissions of Air Pollutants - Waste will be delivered to the site by marine vessel and from the territory-wide waste the cumulative distance to be travelled is estimated to transportation between the RTSs be 410km. and the site 6 Overall Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment
1 Distance to areas of noise O There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the artificial island site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (only applicable if there are Therefore, this criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O ‘Neutral’.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial island. Not relevant. 2 Potential for sediment O None. EPD routine sediment quality monitoring data contaminant release collected near to EWIL shows that the marine sediment is not contaminated. 3 Potential impacts on WSRs O / - The presence of the artificial island will result in very (including increase or minor changes to the hydrodynamics in the area. No exceedance of WQO) WQO exceedance would be caused in the construction phases.
It is predicted that both DO and TIN standards in the operational phase would be breached, however, these were both breached in the baseline scenario and the elevations due to the presence of island were not significant, therefore, the island would not be the cause of the exceedances. 4 Potential Impacts on O Artificial island. Not relevant. Groundwater 5 Potential Cumulative Impacts O / - There are a number of dredging and backfilling projects in the area, (East Tung Lung / E of Ninepin) which may contribute to the filling related pollutants in the water column. Assumed that the potential submarine gas pipeline connecting (GRT) at Cheng Tou Jiao in China to Lamma PS would be completed prior to EWIL construction. 6 Overall Impact O / - ‘Neutral / Negative – Low’. The site is some distance from WSRs, however marginal decrease in water quality anticipated during construction and operation. Waste Management Assessment 1 Balance of Materials + The site could accommodate a major volume of public (surplus/deficit of public fill fill (400Mcum) negating the need to import filling needed for landfill development) material for site formation. Dredged muds will be incorporated with the fill materials within the island footprint. 2 GHG emissions from mode of - Waste will be delivered to the site via marine vessel. transport for delivery of waste to The distance travelled from marine RTS(s) to the site the site from RTSs has been estimated to be 410km. 3 Overall Waste Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance out of the benefit for being able to accommodate C&D surplus materials and the relatively larger amount of GHG emissions for the longer distance travelled.
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary - Whilst distant, minor impacts possible at the Bluff environmental impacts on “Areas Island & Basalt Island SSSI and Marine Reserve at of Absolute Exclusion” Cape D’Aguilar (11km and 16km to the west, respectively). In addition, a Conservation Area has been proposed around Sai Kung Peninsula, (Bluff Island to Tai Long Wan). 2 Affects an important habitat - / - - The primary concern regards potential sedimentation and increased turbidity of the water column around the ecologically sensitive Victor Rock (~3km from the potential EWIL) that is habitat to a diverse coral community of conservation importance. The Inner Eastern Waters also support scattered coral communities of conservation value that could potentially be adversely affected by filling works.
The area is not a core part of the Chinese White Dolphin or Finless Porpoise habitat. Benthic habitats are not of high conservation value. 3 Affects a species of conservation - /- - All hard (stony) corals, such as those prevalent at importance Victor Rock, are protected in the HKSAR under the Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187).
The Finless Porpoise is listed under Appendix I of CITES and is protected under the Wild Animals Protection Ordinance (Cap. 170). The density of sightings in this area is moderate. 4 Potential for Cumulative - There are a number of dredging and backfilling projects Ecological Impacts on species / in the area, (East Tung Lung / E of Ninepin) which may habitat of recognised value contribute to the filling related pollutants in the water column. The Lamma Power Station / Shenzhen submarine gas pipeline would be completed prior to EWIL construction. 5 Overall Ecological Impact - / - - Although modelling does not predict significant water quality decline associated with the works, the area is of broad conservation value as illustrated by the proposal to designate a Conservation Area around the Sai Kung Peninsula. In particular, the area is of conservation value due to the presence of ecologically valuable and sensitive coral reef habitat at Victor Rock, and a range of scattered coral communities around Inner Eastern Waters. As such, the overall impact potential is ‘Negative – Low / High’.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary - There are no existing “Areas of Absolute Exclusion” environmental impacts on “Areas likely to be affected by the works. However, a of Absolute Exclusion” Fisheries Protection Area has been proposed at Port Shelter, with a “no take artificial reefs deployment area”, proposed at Outer Port Shelter. Whilst there is some potential for impact, the output of the numerical modelling exercise does not support the potential for direct impacts. 2 Affects an important mariculture - The fishing zone in the vicinity of the site has generally / fisheries resources (including low fisheries productivity in the HKSAR. Spawning and spawning / nursery ground) nursery ground for a range of commercially important fish and crustaceans are found some distance from the site at Port Shelter. 3 Potential for Cumulative - Backfilling projects in the area, (East Tung Lung / E of Fisheries Impacts on sites of Ninepin) may contribute to the filling related pollutants recognised value in the water column negatively impacting fish species. 4 Overall Impact - Fisheries impacts are considered to be ‘Negative – Low’. The site area itself is of relatively low fisheries importance. The nearest areas of high value fisheries are located at inland waters. However the Port Shelter area to the west is also a nursery ground where fisheries protection measures including a FPA and artificial reef have been proposed. Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites 2 Potential for archaeological - The site is remote from land based archaeological sites value with links to maritime activities. An historic shipwreck together with pottery / porcelain shards and glass beads was found in the waters now occupied by High Island Reservoir in 1974. Notwithstanding the lack of archaeological data currently available at the site, it is considered that the likelihood of archaeological remains in this area is limited. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O There are no planned or confirmed projects, which may Heritage Impacts on sites of cause cumulative heritage impacts. recognised value 4 Overall Impact O ‘Neutral’. The potential impacts on cultural heritage are considered to be negligible. Whilst the occurrence of a shipwreck at High Island Reservoir is of interest, the site is remote from land based archaeological sites with links to maritime activities. A detailed marine archaeological investigation should be carried out in any future studies.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no Resources significant impacts on landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - - Construction and operation of the island will be Character incompatible with the open and natural and tranquil landscape qualities of the area. Once completed, the afteruse mitigation will reduce the overall impact of the island a little. However, this landfill will still be incompatible with existing landscape character and resulting impacts will be Negative – High. 4 Visual Impacts - The number of VSRs affected by the site is very few and most of these are very distant. The most affected VSRs are a limited number of recreational VSRs which use the area for passive and active recreation. Generally therefore, visual impacts will be Negative – Low. 5 Overall Impact - Overall, landscape and visual impacts will be ‘Negative – Low’ for the following reasons: • There are no landscape designations covering the disposal site; • No significant landscape resources are affected; • The open, natural and isolated landscape character of the Eastern Coastal Waters will be significantly compromised; • There are very low numbers of residential VSRs within the visual envelope of the site and an extremely small number close to it.
Landfill Gas Assessment 1 Distance between the new / O The nearest sensitive receivers are >250m from the extended landfill and SRs site. 2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. the LFG Consultation Zone) 3 Man Made/Natural Pathways for O None. LFG Migration 5 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce Greenhouse Gas use) Emissions 6 Overall Landfill Gas Impact O ‘Neutral’.
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Table 13.2: Summary of Eastern Waters Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact O / - Neutral / Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact O Neutral Overall Landscape & Visual Impact - Negative – Low Overall Landfill Gas Impact O Neutral
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Table 13.3 Assessment of Significance of Visual Impacts of Eastern Waters Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum Nos. of Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR of magnitude Construction High) before Mitigation (Insubstantial, and Source(s) only) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Recreational Receivers VR68 Shek O 23km Many Negligible Medium Insubstantial Insubstantial VR69 Clear Water Bay 16km Many Negligible Medium Insubstantial Insubstantial VR70 Tai Wan Beach, Tai Long 16km Few Negligible Medium Insubstantial Insubstantial Wan/Maclehose Trail VR71 Leung Shuen Wan Chau (High 19km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0-15km Very Few Small Medium Moderate to Slight Insubstantial Diving and other Water sports activities Travelling Receivers VR49 Maritime Vessels 10-20km Few Negligible Low Insubstantial Insubstantial
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Table 13.4 Assessment of Significance of Visual Impacts of Eastern Waters Island Landfill During Afteruse Phase (Note: All impacts are adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR of magnitude Afteruse High) before Mitigation (Insubstantial, and Source(s) only) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Recreational Receivers VR68 Shek O 23km Many Negligible Medium Insubstantial Insubstantial VR69 Clear Water Bay 16km Many Negligible Medium Insubstantial Insubstantial VR70 Tai Wan Beach, Tai Long 16km Few Negligible Medium Insubstantial Insubstantial Wan/Maclehose Trail VR71 Leung Shuen Wan Chau (High 19km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0-15km Very Few Small Medium Moderate to Slight Insubstantial Diving and other Water sports activities Travelling Receivers VR49 Maritime Vessels 10-20km Few Negligible Low Insubstantial Insubstantial
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14. TAI LONG WAN OFFSHORE ISLAND LANDFILL 14.1 Basic Information Project Title 14.1.1 Tai Long Wan Offshore Island Landfill (TLWOIL) – marine site M.9. Nature of Project 14.1.2 The Project would form a new marine based waste disposal site in waters located within Tai Long Wan Offshore (Figure 14.1). 14.1.3 The TLWOIL would require the construction of an artificial island of approximately 875ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. The Tai Long Wan Offshore waste disposal facility would be constructed as a “stand alone” facility, procured through competitive tendering. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 14.1.4 The TLWOIL is located approximately 8km to the east of Tai Long Wan. Approximately 380Mcum of fill material will be required to construct the artificial island, with a final site formation level to around +6mPD. The capacity of the landfill site would be in the order of 140Mcum. 14.1.5 Seabed levels in this area vary from 20 to 35m below Chart Datum. There would be a requirement to dredge some 15Mcum of marine muds in the construction of the seawall.
History of Site 14.1.6 The TLWOIL is located within open marine waters and is to be formed entirely as part of this project. There has been no previous development activity within the site area.
Number and Types of Designated Projects Covered 14.1.7 The TLWOIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. 14.2 Outline of Planning and Implementation Programme 14.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 14.2. Assuming landfill operations start in 2022, the TLWOIL would be full during the period 2040 to 2050, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 14.2.2 The site is not currently covered by any statutory town plans, as described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 14.2.3 According to the Territorial Development Strategy Review, the area where the site is located is of potentially high recreational value. There are no other identified uses in this area. 14.2.4 The South East New Territories (SENT) Development Strategy Review focused on conserving the natural environment of the sub-region. The SENT Strategy Review proposed areas for inshore water recreation marine park and marine conservation areas in the coastal areas of Port Shelter. 14.3 Possible Impacts on the Environment 14.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the TLWOIL are outlined below. Figure 14.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 14.1 and 14.2.
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Air Quality 14.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
14.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site: the closest one being Sai Kung East Country Park which is located some 7km east of the site boundary. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 14.3.4 The site lies in an open marine area, with no known developments (existing or planned) within 5km from the site boundary. The build-up of air pollutants is not anticipated. 14.3.5 Maine vessels will be used for delivering waste to the site. The amount of air pollutants emitted from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. However, the estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 490km. Given the distance to be travelled, the regional air quality impacts may be moderate.
Noise 14.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
14.3.7 No noise sensitive receivers are found within a 300m radius from the boundary of this site. Thus, no significant noise impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 14.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue for this site. 14.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 14.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
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Water Quality Baseline Conditions at the Site 14.3.11 The site is located at the eastern-most waters of Hong Kong at the mouth of Mirs Bay, and falls within the Mirs Bay Water Control Zone. It is sited in the exposed waters approximately 6km east of the Sai Kung Peninsula, and to the south of the Dapeng Bandao (within Mainland waters). The current in the vicinity of the artificial island site is weak during both the dry and wet seasons, with a flow of < 0.5m/s. The strongest current in the area is the dry season flood tide from the northeast. 14.3.12 EPD routine marine water and sediment quality monitoring is undertaken at stations MM15 and MS15 some 2km southwest of the island site. The monitoring data obtained from these two stations indicates that the marine water quality is good, with full compliance with the WQOs for dissolved oxygen (DO), total inorganic nitrogen (TIN), un-ionised ammonia and E- Coli for the past three years.1 Likewise, the marine sediment in the area is of good quality, with no exceedance to the Lower Chemical Exceedance Level. The sediment is thus suitable for open sea disposal and the potential for impacts associated with contaminated muds is considered limited. Key Issues and Sensitive Receivers 14.3.13 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
14.3.14 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the site. These include:
• Secondary contact recreation subzone along the eastern coastline of the Sai Kung Peninsula from Sha Tau Kok to Tung Lung Chau including the coastline of Bluff Island, Fu Tau Fan Chau Wang Chau and Basalt Island; • Gazetted beaches at Clear Water Bay; and • Ungazetted beaches at Tai Long Wan.
14.3.15 In addition, there are a range of aquatic and inter-tidal ecological receivers in the vicinity of the site that would be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the “Ecology” and “Fisheries” subsections. The sensitive receivers include:
• SSSIs at Tai Long Wan, Bluff Island / Basalt Island, and the Ninepin Group; • Proposed Sheltered Island Marine Park / Reserve; • Potential Marine Park / Reserve at Bluff Island and North & South Ninepin; • Potential Marine Park / Reserve at Long Ke Wan and Pak Lap Wan; • Potential Marine Park / Reserve at Tai Long Wan; • Coral and Green Turtle habitats near Ninepin Group, Basalt Island, Ching Chau and Tung Lung Chau; and • Fish culture zones at Tap Mun and Kau Lau Wan.
1 EPD, Marine Water Quality in Hong Kong for 2000, (EPD 2000)
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Reclamation and Site Formation 14.3.16 Dredging of some 15Mcum of uncontaminated sediment is proposed for the site development, and there will be reclamation works to create a site footprint of around 875ha. Sediment handling for these activities may give rise to potential water quality impacts from increased suspended solids and reduced dissolved oxygen levels in the water column. Whilst dredging is proposed for this site, EPD data shows that the sediment quality in this area is uncontaminated with no potential for contaminant release. 14.3.17 The placement of fill for island construction may lead to localised increases in suspended solids levels. The modelling in the Water Quality and Hydrodynamic Assessment Report indicates that the impacts of island construction on SS are fairly small and at no time do the predicted levels approach or exceed WQO. In addition, the predicted sedimentation rates at the surveyed corals are well below the assessment criterion of 100/m2/day. The highest SS level increase is predicted to occur at SC14 (4.83%) during the Phase 2 construction dry season. Hydrodynamic and Water Quality Impacts Following Island Formation 14.3.18 It is predicted that the island would not cause any significant differences (less than 3%) on accumulated flow through major channels. The presence of the artificial island may cause some localised significant changes in velocity fields in the vicinity. The modelling predicted that the presence of the island would cause an overall increase in average current velocity of 18.89% to the north and an overall reduction in average current velocity of 3.57% to the south-east. 14.3.19 In the hydrodynamics and water quality modelling, 34 sensitive receivers that are close to the site were selected for presentation. Of the 34 chosen indicator points, 18 are located in the Mirs Bay WCZ (MP4, FC14, MP1, FC13, GT3, SC10, FC12, SC6, FN1a, MP8, MP8b, MP9, SC8, SC12-14, SC17, SC21), 2 in Tolo Harbour & Channel WCZ (MP2, SC9), 4 in Port Shelter WCZ (MP7, SC16, GB7 and FC6), 8 in Southern WCZ (SC3, 4, 11, 18, NS6, 7, FP6, GT2) and 2 are located within the boundary of Mainland (MF, SB). 14.3.20 According to the dry season water quality modelling results, the predicted 90%ile DO at Hong Kong sensitive receivers for depth average and bottom layer ranged from 5.86 to 6.89mg/L which complied with the WQO of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO. The predicted depth averaged DO levels at the 2 indicator points in Mainland waters (MF and SB) also complied with the Mainland standard of ≥5mg/L. 14.3.21 The predicted average salinity levels in the dry season were in the range of 33.88 to 34.00ppt. The predicted levels for operational phase were comparable to baseline scenario with the largest deviation of 0.03%. These differences are minimal in comparison to the WQO of ±3ppt for Tolo Harbour and Channel WCZ as well as 10% for all remaining WCZ. 14.3.22 The predicted SS levels in the dry season ranged from 0.95 to 4.30mg/L. The largest increase in SS levels caused by the presence of the island would be at MP8b (Water Quality Monitoring Station at Tai Long Wan) with a percentage increase of 11.18%. Recognising that the WQO requires that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, these differences are considered acceptable. 14.3.23 The predicted E Coli levels in the dry season at all of the selected indicator points would be 2 or less count/100mL that are well below the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. Compared to the baseline scenario, no notable changes were observed at any of the indicator points. 14.3.24 The predicted average dry season UIA (0.00178-0.00348mg/L) would be quite small in comparison to the WQO of 0.021mg/L and the Mainland standard of 0.02mg/L. The largest increase caused by this site would be at MP8b (Water Monitoring Station at Tai Long Wan) with a value of 5.23%.
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14.3.25 The dry season TIN levels ranged from 0.0690 to 0.0958mg/L that is below the WQO of 0.1mg/L for Port Shelter and Southern WCZ and 0.3mg/L for Mirs Bay WCZ as well as the Mainland standard of 0.3mg/L. Since the WQO for TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the yearly values. The calculated annual mean would be in the range from 0.070 to 0.1537mg/L and exceedances were found at SC3, 4, 11, 16, 18, GB7, FC6, NS6, 7, FP6 and GT2. However, the averaged baseline values (0.1026 to 0.1547mg/L) at these 11 stations also exceeded the WQO. All these stations are located in Port Shelter WCZ and Southern WCZ with an annual mean WQO of 0.1mg/L. The predicted values at the remaining stations complied with their respective WQOs. The maximum percentage increase would be at SC11 (Surveyed Corals at Po Toi Island) with value of 3.3%. 14.3.26 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average and bottom layers ranged from 1.70 to 5.33mg/L. In Hong Kong waters, indicator points FC14 (Fish Culture Zone at O Pui Tong), MP1 (Yat Chau Tong Marine Park) and FC13 (Fish Culture Zone at Wong Wan) breached the WQO for DO in Mirs Bay WCZ while MP2 (Hoi Ha Wan Marine Park) and SC9 (Surveyed Corals near Tolo Channel) breached the Channel Subzone of Tolo Harbour WCZ for 90%ile bottom DO. However, the predicted 90%ile DO for the baseline scenario at these 5 points would also be below the WQO. The maximum percentage reduction from baseline levels for these 5 indicator points would be at FC14 (Fish Culture Zone at O Pui Tong) with value of 4.41% or 0.16mg/L. In Mainland waters, the predicted bottom 90%ile DO levels at MF (ranged from 3.63 to 5.00mg/L) and SB (ranged from 1.49 to 4.24mg/L) exceeded the Mainland standard of 5mg/L but, again, the predicted baseline values at these 2 stations also exceeded the Mainland standards. The predicted DO levels at the remaining stations complied with the WQO of ≥4mg/L for depth averaged 90%ile DO and ≥2mg/L for bottom layer 90%ile DO. 14.3.27 The predicted average wet season salinity would be in the range of 25.00 to 31.41ppt. It is predicted that the island would cause small impacts to the baseline salinity level at all of the indicator points. The largest predicted deviation would be at SC11 with a value of -1.47% or 0.39ppt. The percentage differences in salinity level caused by the presence of this site would be very small as compared to the WQO that change due to any waste discharge shall not exceed 10% of natural ambient level. 14.3.28 The predicted SS levels in the wet season ranged from 1.62 to 4.55mg/L. The largest increase in SS levels caused by the presence of the island was at SC11 of 3.77%. The percentage increases are small, recognising that the WQO requires that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man- made increment should not exceed 100mg/L. 14.3.29 The predicted E.coli levels in the wet season at all of the selected indicator points would be 2 or less count/100mL that are very low and well below the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. Comparing to the baseline scenario, no notable changes were observed at any of the indicator points. 14.3.30 The predicted average wet season UIA (0.00302 - 0.00497mg/L) were very small as compared to the WQO of 0.021mg/L as well as the Mainland standard of 0.02mg/L. 14.3.31 The predicted wet season TIN levels ranged from 0.0678 to 0.2147mg/L. The largest TIN level was predicted at GT2 (Green Turtle site at Po Toi) with value of 0.2147mg/L. Comparing with baseline levels, the percentage changes ranged a between –1.66 to 4.37%, with the largest increase (4.37%) located at FC6 (Fish Culture Zone at Po Toi Island). Since the WQO for TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The results are discussed in Section 14.3.25 above. Meanwhile, for Mainland waters, the predicted TIN values (ranged from 0.0623 to 0.802mg/L) at the 2 indicator points, MF and SB, would be well below the relevant standard of 0.3mg/L.
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Cumulative Impacts 14.3.32 It is understood that a submarine pipeline is to be installed through Mirs Bay to carry LPG from Cheng Tou Jiao (northeast Mirs Bay) to the Lamma Island power station. The pipeline will run nearby to the west of the artificial island site. These works however are due to be complete within two years of commencement (pending) and would not give rise to any potential for cumulative effects. 14.3.33 Whilst there are fill management activities in the general Eastern Waters area, there are no activities in the vicinity of the artificial island site. Furthermore, there are unlikely to be any future such activities in the immediate vicinity as previous investigations on behalf of CED have identified the area to be too “sensitive” (i.e., on environmental or other grounds).2 The nearest areas of activity are the South of Victor Rock sand borrow area (10km south) and the adjacent East of Ninepin mud disposal area. Given the weak current in the area, there is limited potential for cumulative effects with works at these areas.
Waste Management / Disposal Impacts 14.3.34 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 14.3.35 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 14.3.36 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 380Mcum • Volume of muds be dredged for outer sea wall: 15Mcum
14.3.37 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 14.3.38 Waste delivery to the TLWOIL will be by marine vessel, which has lower GHG emission rate (per kg waste handled) than delivery by vehicle road truck. However, the cumulative distance between marine RTSs and the site is around 490km (refer to Preliminary Marine Review (March 2002)), the impacts associated with GHG emissions is considered to be moderate.
Ecology Baseline Conditions 14.3.39 The site is located in offshore waters in Mirs Bay, some 6km due east of Tai Long Wan in the Sai Kung East Country Park. Coastal areas of the Sai Kung West (Extension) Country Park and the Plover Cove (Extension) Country Park are located some 14km and 16km northwest respectively. The Tung Ping Chau Marine Park is located 14km due north, whilst the Hoi Ha Wan Marine Park and the Double Haven Marine Park are located 16km and 21km northwest respectively.
2 CED (2001). Map of Marine Fill Resources, Mud Disposal Areas and Major Reclamations. Fill Management Division.
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14.3.40 It is noted that a Potential Marine Conservation Area for the area has been proposed. The Conservation Area would encompass coastal waters (-10mPD) around the East Sai Kung Peninsula from Tai Long Wan to Bluff Island and Kau Sai Chau in Port Shelter.3 14.3.41 Some 8km west of the site is the Tai Long Wan SSSI. Other protected areas in the broader area to the southwest include the Ninepin SSSI (14km), the Bluff / Basalt Island SSSI (14.5km) and the proposed Shelter Island Marine Reserve / Park (16km). Beyond these, the Cape D’Aguilar Marine Reserve and SSSI are 26km southwest of the artificial island site. 14.3.42 There have been a number of marine ecology surveys undertaken in the vicinity of the proposed TLWOIL site, including a series of surveys undertaken under the Fill Management Study – Phase IV by CED. Reference is made to these surveys as follows: 14.3.43 A number of underwater dive surveys were made in coastal waters between 1991 and 1994. Surveys of the northeast Sai Kung peninsula (8km northwest of the site) reported encrusting hard corals, soft coral and gorgonians. The seaweed Sargassum was reportedly abundant at shallow sub-tidal Tai Long Wan beach (8km west) and provided a good habitat for a range of crabs and small fish, whilst barnacles and hard coral was present at the north tip of the Bay (Tai Long Tsui Wan – 6km west). The coral communities at Breaker Reef and Shek Ngau Chau (8km north) supported a highly diverse community of reef fish, hard and soft corals. 14.3.44 Victor Rock (8km southeast) is a submerged rocky pinnacle and a recognised as a site of conservation importance by virtue of its diverse communities of hard and soft coral, gorgonians, sponges, holothurians, sea urchins, sea fans and fish species. 14.3.45 The surveys concluded that the conservation value of each of these dive sites was “high”. There have been no events in recent times that would have devalued the conservation value of these sites. 14.3.46 The same study concluded that the more distant coral communities at the Ninepin Group (14km southwest) and Bluff Island / Basalt Island (14.5km southwest) are also of high conservation value. These sites are characterised by diverse communities of hard and soft coral, gorgonians, sponges, holothurians, sea urchins, sea fans and fish species. It is noted that six major types of corals including all hard (stony) corals are protected in the HKSAR under the Animals and Plants (Protection of Endangered Species) Ordinance (Cap. 187). 14.3.47 For benthic community, dive surveys east of the Ninepin Group showed that the seabed was dominated by burrowing spionid polychaetes. 4 Other abundant groups in the epi-benthic community would be echinoderms and crustaceans, whilst the scavenging gastropod Nassarius siquijorensis was abundant at seabed areas around Basalt Island. Given the similarity in sediment character and water column depth at these locations and the proposed Tai Long Wan Offshore site, benthic community assemblages at the site are expected to be similar. From dive surveys at Breaker Reef, the benthic community at –15mPD was reported to support soft corals, gorgonians and sea anemones.5 14.3.48 There have been occasional sightings of the Black Finless Porpoise Neophocaena phocaenoides in offshore waters around the artificial island site. Compared with observations of this species in other offshore waters around the HKSAR, it can be concluded that the waters around the site do not form part of the core habitat for the species. The Finless Porpoise is protected under the Wild Animals Protection Ordinance (Cap. 170) and are listed in CITES Appendix I. There is some likelihood that the Green Turtle visits Mirs Bay as it has been observed at a number of locations to the southeast of the area (i.e., Tung Lung Chau, Ching Chau, Ninepin and Po Toi).
3 City Planning (2001). Study On South East New Territories Development Strategy Review: Conservation Summary. For PlanD, Govt. of HKSAR. 4 ERM-Hong Kong Ltd (1997d) Seabed Ecology Studies: East of Ninepins Final Report, Civil Engineering Department, Hong Kong Government.
5 Binnie Consulting Ltd. (1995). 1994 Hypoxia and Mass Mortality Event in Mirs Bay: Final Report. For CED.
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Direct Habitat Loss 14.3.49 Around 875ha of benthic habitat and some 20-30m of water column over this seabed area will be lost to the island landfill development. Although the area is large, the ecological value of the seabed is not expected to be significant. The loss of water column would be reflected in loss of fisheries habitat. From available data, the area does not appear to be of particular ecological value to either the Finless Porpoise or Green Turtle. Water Quality / Hydrodynamics 14.3.50 As the baseline water quality conditions in the area are good, the potential for water quality decline is related to increased suspended sediment / sediment deposition and turbidity during dredging and reclamation works, and the associated potential for decreased dissolved oxygen levels. 14.3.51 There are a number of coral communities within a range of 6-8km of the island site that are of high conservation value. These communities are located in all directions to the north, west and south of the site and thus any transport of sediment in these directions will give rise to potential adverse impacts on the coral reef community. If any sediment plume that was to form were transported southeast of the site there may be potential for impacts upon a wide range of sensitive receivers from the mouth of Port Shelter to Po Toi. 14.3.52 During the construction phase, the model output shows that suspended sediment levels in the waters around the site may experience a marginal increase in suspended solids levels. Under a worst-case scenario for each of the three construction phases, wet season works display the highest predicted sediment levels. During Phase 1 construction the highest predicted sedimentation rate is 1.2 g/m2/day at the East Ninepin coral community (SC6). Phase 2 construction gives a worst-case scenario of 1.9 g/m2/day at the coral community near Victor Rock (SC14), whilst the worst-case sedimentation rate for Phase 3 consturction is 1.4 g/m2/day – also near SC14. 14.3.53 The dry season sedimentation rates do not exceed 1.4 g/m2/day (predicted at SC14). In all cases the predicted sedimentation rates are not significant compared with the limit of 100 g/m2/day. 14.3.54 It is noted that intrusion of hypoxic water into Mirs Bay in 1994 lead to deaths of a large number of marine organisms in the north of the bay, whilst the effects of hypoxia were relatively minor at Breaker Reef. This was attributed to sufficient mixing of the water column around Breaker Reef due to the greater oceanic influence in this area.6 Thus, there is some theoretical potential that the site may reduce water column mixing on the leeward side (north and northeast), and thereby generate more favourable conditions for stratification and a decline in water quality. 14.3.55 Despite this potential, the model does not predict any significant effect on ecological receivers in the vicinity of the site. The worst-case operational phase increases in suspended sediment being 0.15mg/L near the coral community at Pak Lap Wan (SC13) (southwest of the site) and 0.18mg/L near the coral community at Wong Mau Chau (SC21) (northwest of the site). Marine Vessel Disturbance 14.3.56 From available data, the site area does not appear to be particularly important as a habitat for the Finless Porpoise. However, if marine vessels approach the site via the south of Po Toi group of islands there will be some potential for vessel collision with the Finless Porpoise and possibly the Green Turtle. There would also be greater likelihood for general disturbance from vessel movements through this area (e.g., vessel engine noise and vibration).
6 Binnie Consulting Ltd. (1995). 1994 Hypoxia and Mass Mortality Event in Mirs Bay: Final Report. For CED.
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Fisheries 14.3.57 The broader “Eastern Waters” area is of ecological and commercial fisheries importance, although it is the inland waters between Port Shelter, Tung Lung Chau, Cape D’Aguilar and Po Toi that are by far the most productive.7 This area has been proposed as a fisheries spawning area. The inland waters are an important spawning ground for a number of commercially species, including Apogon quadrifasciatus (broadbanded cardinalfish), Parapristipoma trilineatum (chicken grunt), Sebasticus marmoratus (scorpionfish), Trichiurus haumela, Upeneus sulphureus (sulphur goatfish) and U. tragula (freckled goatfish). Port Shelter is also an important nursery area for P.trilineatum as well as fry and juveniles of the high value red pargo Chrysophrys major and gold lined seabream Rhabdosargus sarba. 14.3.58 In the offshore waters that are more characteristic of the artificial island site, there is still fishing activity, albeit less concentrated. The fisheries value of the waters around the site are not known as fishing effort tends to be concentrated in inland waters, although the area is likely to be of importance for natural fisheries recruitment. In support of this statement dive surveys in the area around Breaker Reef (8km north) reported a wide range of reef fish including P. trilineatum, tuna and mackerel. At nearby Shek Ngau Mei, “schools of Chromis, some wrasse and other small reef fish” were reported. 14.3.59 The key concern with respect to fisheries activities is the potential for sediment plume formation and transport from dredging and reclamation activities. The hydrodynamics of the area may carry sediment in almost any direction. Particularly sensitive would be the commercially valuable inshore fisheries around the Sai Kung Peninsula to the west and southwest. Beyond these waters, further inland and / or southwest, there is potential for impact upon an important fisheries spawning zone between the Ninepin Group and Tung Lung Chau that has been proposed for protection. 14.3.60 Whilst there are a number of fish culture zones in the broader area, those northeast of the site at Tap Mun and Kau Lau Wan (both 12km away) are the closest. Reference to the generalised water current patterns alone for the area would not suggest that these zones would be affected by any sediment plume from dredging and reclamation activities, although under the combined influence of the southwest monsoon and southeast offshore winds there is some slight potential for impact upon one or both of these zones. It is not considered likely that the other fish culture zones in sheltered areas to the southwest would be affected due to the distance and hydrodynamics.
Cultural Heritage 14.3.61 This site is located some distance offshore. There is no immediate evidence of archaeological remains in this area or in the near vicinity. The nearest sites of known archaeological interest are located at the Sai Kung Peninsula. The Ham Tin Archaeological Site is situated at Tai Long Wan, approximately 10km from the site. This Archaeological Site is of high archaeological interest as cultural relics of the late Neolithic and Bronze Age dated between 4,000 to 2,500 years ago have been found. 14.3.62 An historic shipwreck was found in the waters now occupied by High Island Reservoir (formerly known as Kwun Mun Channel) in 1974. The shipwreck, dating to late Song-early Ming Dynasties, was found during the construction of the High Island Water Scheme. Together with the shipwreck, some pottery and porcelain shards and glass beads of Indian origin were also recovered. 14.3.63 Given the remoteness of this site from known land based sites of cultural heritage interest, the likelihood of archaeological remains in this area appears limited. However, given the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
7 ERM (1998). Fisheries Resources and Fisheries Operations in Hong Kong Waters. For AFCD, Govt. of HKSAR.
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Landscape and Visual 14.3.64 Landscape Planning Designations – This area of landscape is not covered by any planning designations reflecting landscape values and so there will be no impact on these values. 14.3.65 Landscape Resources - As the site lies in a marine area, there are no impacts on landscape resources. 14.3.66 Landscape Character - The island landfill lies in the Eastern Coastal Waters LCA. This is an expansive area of open water to the east of Sai Kung Country Park, lying on the edge of the South China Sea. There are no major shipping channels in the vicinity of the site. Approximately 18km to the west of the site, is Tai Long Wan and Sai Kung East Country Park, an area of undeveloped upland countryside characterised by largely natural hillsides, coves and beaches. The offshore landscape of this area is natural, remote and tranquil. 14.3.67 There exists potential for significant impacts on landscape character resulting from construction works that will introduce new artificial elements incompatible with the existing natural and tranquil landscape character. The predicted impact on landscape character during the construction/operation phase of the project will be substantial. At the end of the construction/operation phase, these impacts are likely to be reduced, as the completed island is restored and the landscape mitigation measures are fully implemented. However, the scale of the island is large and the form and the profile of the island and the coastal edge finishing will be rather artificial in nature. The character of the island is therefore incompatible with the existing natural landscape character. As a consequence, the long-term impact on landscape character will be moderate/substantial. 14.3.68 VSRs - VSRs affected by the island landfill are identified in Tables 14.3 and 14.4 the extent of the project visual envelopes is shown in Figure 14.5. 14.3.69 As the site is approximately 18km from the Sai Kung Country Park, there are no VSRs close to the site. VSRs significantly affected by the island landfill are limited to recreational VSRs in Sai Kung East Country Park (principally on the Maclehose Trail, Tai Long Wan, Sai Wan and Ham Tin Wan). Other recreational VSRs will be the visitors to the potential areas for boating, fishing, diving and other water sports activities. Other VSRs, such as travellers on vessels using the shipping route, are few in number and transient. 14.3.70 The VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as relatively close artificial elements contrasting with the coherent qualities of the existing landscape. However, given the distance between the VSRs and the landfill island, the visual impacts will be generally slight to insubstantial. After the restoration of the landfill island, the visual impact of the island will be reduced further.
Landfill Gas 14.3.71 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 14.3.72 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
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14.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 14.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to this artificial island site.
Air Quality 14.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 14.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 14.4.4 No specific water quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Waste Management / Disposal Impacts 14.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 14.4.6 It is proposed that marine vessel movements to the site are routed to avoid passage through areas of high ecological value, such as the Ninepin Group SSSI and the Finless Porpoise habitat the east of Po Toi.
Fisheries 14.4.7 There are no particular measures that are proposed for fisheries resource protection.
Cultural Heritage 14.4.8 There are no particular measures that are proposed for protection of cultural heritage resources.
Landscape & Visual 14.4.9 Mitigation Measures – Landscape and visual mitigation measures are identified in Part A of the Report and are illustrated in Figure 14.8.
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14.5 Summary 14.5.1 A summary of the SEA for the TLWOIL is provided in Tables 14.1 and 14.2:
Table 14.1: Tai Long Wan Offshore Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within 500m land use of the artificial island site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours would or exacerbate impacts accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant O The site is located in open marine waters to the west of emissions (TSP (construction), Tai Long Wan, with no known developments that have NOx, CO, SO2 – LFG Flare) relevant emissions within 5km from the site. taking into account ambient conditions 5 Total Emissions of Air Pollutants - Waste will be delivered to the site by marine vessel and from the territory-wide waste the cumulative distance to be travelled is estimated to be transportation between the RTSs 490km. and the site 6 Overall Impact O / - Overall air quality impacts are considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment
1 Distance to areas of noise O There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the artificial island site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (Only applicable if there are Therefore, this criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O ‘Neutral’.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O As a marine site, no water course diversion is required. 2 Potential for sediment O The sediment in the area has been proved to be contaminant release uncontaminated as part of EPD’s routine monitoring programme. As such, the potential for the release of sediment bound contaminants from the dredging work is considered to be limited.
3 Potential impacts on WSRs O / - Water quality modeling indicates that the construction of the island may cause some increase in SS but that remains below the WQO.
It is predicted that both DO and TIN standards in the operational phase would be breached, however, these were both breached in the baseline scenario and the elevations due to the presence of island were not significant, therefore, the island would not be the cause of the exceedances. 4 Potential Impacts on O As a marine site, there are no groundwater issues. Groundwater 5 Potential Cumulative Impacts - There is a proposal for installing a submarine gas (Potential for concurrent projects pipeline linking Cheng Tou Jiao in China to the Power to exacerbate preceding Station at Lamma Island. The alignment of the proposed impacts) gas pipeline may run in a close proximity to the artificial island site. If the works were to be undertaken concurrently, there would likely be cumulative water quality impacts, in particular localised increased in suspended solids.
It is considered that there is potential for fill management marine activities in the area to be concurrent with development of the artificial island site. However, due to the distance involved and the hydrodynamics in the area the potential for cumulative impacts is limited.
6 Overall Impact - Dredging and reclamation activities may increase sediment level in the water column. The Sai Kung Peninsula to the west is a very popular beach and coastal recreation area that would be adversely affected by any decline in water quality. There is also limited potential for cumulative effects from fill management works in the waters south of the site. Primarily due to the recreational value of the Tai Long Wan inshore area the overall impact potential is ‘Negative – Low’.
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Impacts Score Commentary
Waste Management Assessment 1 Balance of Materials + The site could accommodate significant amounts of (surplus/deficit of public fill public fill (380Mcum), thus negating the need to import needed for landfill development) filling material for site formation. Dredged muds will be incorporated with the fill materials within the island footprint. 2 GHG emissions from mode of - Waste will be delivered to the site via marine vessel. The transport for delivery of waste to distance travelled from marine RTSs to the site is the site from RTSs estimated to be 490km. 3 Overall Waste Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance of the benefit of being able to accommodate C&D surplus materials and the relatively larger amount of GHG emissions for the longer distance travelled. Ecological Assessment 1 Potential for secondary - / - - There are a number of potential Marine Parks / Reserves environmental impacts on “Areas along the coast of the Sai Kung peninsula, in addition to of Absolute Exclusion” the existing Tai Long Wan SSSI. Whilst the numerical model does not predict any significant adverse water quality impact related to island development, there is some potential for localised impacts on ecologically sensitive coral communities in these areas. 2 Affects an important habitat - / - - There are coral habitats of high conservation value around the island site. The water column is of fisheries conservation value, and the sub-tidal waters around the Sai Kung East peninsula to a depth of –10mPD have also been proposed as a Marine Conservation Area. 3 Affects a species of conservation - / - - There have been very occasional observations of the importance Finless Porpoise in waters around the site, although given the scarcity of these sightings the impact potential is marginal. Several species of hard coral are also of conservation importance. 4 Potential for Cumulative O / - There is slight potential for cumulative effects on water Ecological impacts on sites of quality in the area from possible future fill management recognised value activities at the South of Victor Rock sand borrow area and the East of Ninepin marine disposal area. 5 Overall Ecological Impact - / - - The coastal waters around the Sai Kung peninsula are of ecological conservation value. The number of coral reefs makes these waters particularly susceptible to increased sediment levels. Overall, there is potential for a ‘Negative – Low / High’ impact.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary O / - The nearest fish culture zones are at Tap Mun and Kau environmental impacts on “Areas Lau Wan – some 12km northwest of the island site. The of Absolute Exclusion” model does not predict any significant adverse effect upon these sites.
2 Affects an important mariculture - The site is near an important fish spawning area in / fisheries resources (including Eastern Waters, and an important fish nursery area in spawning / nursery ground) Port Shelter. However, given the hydrodynamics in the area, there is no more than a limited chance of adverse impact on these areas.
3 Potential for Cumulative O / - Given the hydrodynamics and locations of potential Fisheries Impacts on sites of concurrent works at South of Victor Rock and East of recognised value Ninepin, there is only any slight potential for cumulative effects on fisheries resources. 4 Overall Impact O / - The remote location of the artificial island site relative to areas of fisheries importance means that the hydrodynamics are unlikely to cause adverse impact. However, as there are sensitive areas to the northwest and the southeast there is slight potential, so overall: ‘Neutral / Negative – Low’. Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites 2 Potential for archaeological - The site is remote from land based archaeological sites value with links to maritime activities. Notwithstanding the lack of archaeological data currently available at the site, it is considered that the likelihood of archaeological remains in this area is low. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O There are no planned or confirmed projects, which may Heritage Impacts on sites of cause cumulative heritage impacts. recognised value 4 Overall Impact O ‘Neutral’. The potential impacts on cultural heritage are considered to be negligible. The site is remote from land based archaeological sites with links to maritime activities. A detailed marine archaeological investigation should be carried out in any future studies.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there are no impacts on Resources landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - - Construction and operation of the island will be Character incompatible with the remote, natural and tranquil landscape qualities of the area. Once completed, the afteruse mitigation will reduce the overall impact of the island a little. However, the landfill will still be incompatible with existing landscape character and resulting impacts will be Negative – High. 4 Overall Visual Impacts - The number of VSRs affected by the island is very few and most of these are very distant. The most affected VSRs are a limited number of recreational VSRs that use the area for passive and active recreation. Generally therefore, visual impacts will be Negative – Low. 5 Overall Impact - Overall, landscape and visual impacts will be ‘Negative – Low’ for the following reasons: • There are no landscape designations covering the disposal site; • No significant landscape resources are affected; • The natural, tranquil and remote landscape character of the Eastern Coastal Waters will be significantly compromised; • There are very low numbers of residential VSRs within the visual envelope of the site and an extremely small number close to it.
Landfill Gas Assessment 1 Distance between the new / O The nearest sensitive receivers are >250m from the site. extended landfill and SRs 2 Number of Receivers within O There are no sensitive receivers within 250m of the 250m (i.e. the LFG Consultation proposed extension. Zone) 3 Man Made/Natural Pathways for O None. LFG Migration 4 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce Greenhouse Gas use) Emissions 5 Overall Landfill Gas Impact O ‘Neutral’.
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Table 14.2: Summary of Tai Long Wan Offshore Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact O / - Neutral / Negative – Low Overall Cultural Heritage Impact O Neutral Overall Landscape & Visual Impact - Negative – Low Overall Landfill Gas Impact O Neutral
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Table 14.3 Assessment of Significance of Visual Impacts for Tai Long Wan Offshore Island Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Construction / Medium, High) before Mitigation (Insubstantial, and Source(s) only) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Recreational Receivers VR70 Tai Wan Beach, Tai Long 10km Small Negligible Medium Insubstantial Insubstantial Wan/Maclehose Trail VR93 Sai Wan 10km Few Negligible Medium Insubstantial Insubstantial VR71 Leung Shuen Wan Chau (High 10km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 15km Very Few Small Medium Moderate to Slight Insubstantial Diving and other Water sports activities Travelling Receivers VR49 On Vessels using the Shipping 13km Few Small Low Slight Insubstantial Lanes
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Table 14.4 Assessment of Significance of Visual Impacts for Tai Long Wan Offshore Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Afteruse Medium, High) before Mitigation (Insubstantial, and Source(s) only) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Recreational Receivers VR70 Tai Wan Beach, Tai Long 10km Small Negligible Medium Insubstantial Insubstantial Wan/Maclehose Trail VR93 Sai Wan 10km Few Negligible Medium Insubstantial Insubstantial VR71 Leung Shuen Wan Chau (High 10km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 15km Very Few Negligible Medium Insubstantial Insubstantial Diving and other Water sports activities Travelling Receivers VR49 On Vessels using the Shipping 13km Few Negligible Low Insubstantial Insubstantial Lanes
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15. SOUTHEAST OFFSHORE ISLAND LANDFILL 15.1 Basic Information Project Title 15.1.1 Southeast Offshore Island Landfill (SEOIL) – marine site M.10. Nature of Project 15.1.2 The Project would form a new marine based waste disposal site in the remote Eastern Waters to the southeast of Hong Kong(Figure 15.1). 15.1.3 The SEOIL would require the construction of an artificial island of approximately 850ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 15.1.4 The SEOIL is located adjacent to the eastern boundary of SAR waters, approximately 18km east of Po Toi Island. Approximately 370Mcum of fill material will be required to construct the artificial island, with a final site formation level to +6mPD. The capacity of the landfill site would be in the order of 140Mcum. 15.1.5 Seabed levels in this area vary from 20 to 30m below Chart Datum. There would be a requirement to dredge some 15Mcum of muds to facilitate seawall construction.
History of Site 15.1.6 The SEOIL is located within open marine waters and is to be formed entirely as part of this project. There has been no previous development activity within the site area.
Number and Types of Designated Projects Covered 15.1.7 This proposal would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. 15.2 Outline of Planning and Implementation Programme 15.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 15.2. Assuming landfill operations start in 2021, SEOIL would be full during the period 2040 to 2050, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 15.2.2 As described in Section 3.3, the site is currently not covered by any statutory town plans, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 15.2.3 According to the Territorial Development Strategy Review, the general area where the site would be located is of recreational value, although in this context these waters in the southeast quadrant of Hong Kong are considered too remote to be of any high value. There are no other identified uses in this area.
15.3 Possible Impacts on the Environment 15.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the SEOIL are outlined below. Figure 15.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 15.1 and 15.2.
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Air Quality 15.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
15.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 15.3.4 No existing or planned developments that emit similar gaseous emissions are found within 3km from the site boundary. Moreover, there are no existing or planned ASRs in the vicinity of the artificial island. Cumulative air quality impacts are not anticipated. 15.3.5 This is a marine site and so marine vessel will be the mode of transportation for waste delivery to the site. The amount of air pollutants emitted from the territory-wide waste delivery to the site will be less compared to a land based site that solely relies on road transport. However, the estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 450km, the regional air quality impacts related to waste delivery is considered to be moderate.
Noise 15.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
15.3.7 No noise sensitive receivers are found within a 300m radius from the boundary of this site. Thus, no significant noise impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 15.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue for this site. 15.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 15.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
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Water Quality Baseline Conditions at the Site 15.3.11 The site is located in the Eastern Waters of Hong Kong, some 18km east of Po Toi Island and 12km to the southeast of Ninepin Group, and falls within the Mirs Bay Water Control Zone (WCZ). The generalised current pattern in the area is from west to east / southeast on the ebb tide, with the result that the artificial island site is only very slightly exposed to water quality influence from more westerly waters. On the flood tide the current direction is from the northeast to west / northwest during the dry season, and from the south during the wet season. Apart from the dry season flood tide when the current flows across the site, the current around the site is generally very weak. However, with the weak currents the arrival of the southwest monsoon (wet season) around late April will have the effect of driving surface waters to the northeast. 15.3.12 Marine water and sediment quality data for the area is available from EPD’s routine monitoring station in Mirs Bay: MM13 and MS13. These stations are located approximately 2km north of the site. The quality of the marine waters in the area is good, with full compliance to the WQO for dissolved oxygen (DO), total inorganic nitrogen (TIN), un-ionised ammonia and E-Coli for the past three years.1 EPD’s routine sediment quality data for the afore-mentioned locations shows no breach of the Lower Chemical Exceedance Level for any of the parameters tested. Excavated sediment from dredging activities would thus be suitable for open sea disposal. Key Issues and Sensitive Receivers 15.3.13 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
15.3.14 There are no Water Sensitive Receivers (WSRs) in the immediate vicinity of the site. Those WSRs most susceptible are common to the area around the East Tung Lung Chau artificial island and include:
• Secondary contact recreation subzone around the Po Toi islands and the east and southeast coasts of Hong Kong Island; • Gazetted beaches at Shek O; and • Seawater abstraction point at Cape D’Aguilar
15.3.15 In addition, there are a range of aquatic ecological receivers in the vicinity of the site that would be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the “Ecology” and “Fisheries” subsections. The sensitive receivers include:
• Cape D’Aguilar Marine Reserve and SSSI; • Ninepin Group SSSI; • Finless Porpoise Area near Po Toi and Wong Ma Kok; and • Coral and Green Turtle habitats near Po Toi, Sun Kong Island and Beaufort Island.
1 EPD, Marine Water Quality in Hong Kong for 2000, (EPD 2000)
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Reclamation and Site Formation 15.3.16 Dredging of some 15Mcum of uncontaminated sediment is proposed for the site development, and there will be reclamation works to create a site footprint of around 850ha. Sediment handling for these activities may give rise to potential water quality impacts from increased suspended solids and reduced dissolved oxygen levels. Whilst dredging is proposed for this site, EPD data shows that the sediment quality in this area is uncontaminated with no potential for contaminant release. 15.3.17 The placement of fill for island construction may lead to localised increases in suspended solid levels. The water quality and hydrodynamic modelling indicated that the impacts of island construction on SS levels at sensitive receivers would be fairly small and at no time would the predicted levels approach or exceed WQO. In addition, the predicted sedimentation rates at the surveyed corals would be well below the assessment criterion of 100/m2/day. The highest SS level increase is predicted to occur at FP9 (4.94%) in the Phase 3 construction wet season. Hydrodynamic and Water Quality Impacts Following Island Formation 15.3.18 The site would be located 12km offshore, with the nearest landfall being the Ninepin Group of islands. The site would be large, with a surface area of some 850ha, and would require a fill volume of approximately 370Mcum to develop. The site would also be located in waters some 20-30m deep and would be a new ‘barrier’ to the oceanic current from the south. No significant impact on accumulated flow in major channels was predicted in the modelling which indicated that all changes would be between –0.98% and 0.28%. The flow velocity fields indicated a significant decrease to the immediate northeast of the island during the wet season, however the overall reduction in current magnitude was only predicted to be 2.65% to the north east, and no overall change in current magnitude was predicted to the north. 15.3.19 In the hydrodynamics and water quality modelling, 46 sensitive receivers that are close to the site were selected for presentation. Of the 46 chosen indicator points, 12 are located in the Port Shelter WCZ (FC6-11, GB7-10, MP7 & SC16), 22 in the Mirs Bay WCZ (FP9, SC5-8, FN1a-d, MP4, 8-11, 8b, GT3 and SC12-14, 15, 17, 21), 1 in the Eastern Buffer WCZ (FC5), 1 in the Mainland waters (MF) and the remaining 10 in the Southern WCZ (NS6-7, SC3-4, 11, MR1, GB6, FP6, SC18 & GT2). 15.3.20 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 5.92 to 7.06mg/L which complied with the WQO of ≥4mg/L for depth averaged DO and ≥2mg/L for bottom layer DO as well as the Mainland sea water quality standard of >5mg/L. 15.3.21 The predicted average dry season salinity ranged from 33.96 to 34.00ppt. Compared to the baseline water quality results, the percentage changes in salinity caused by the presence of the island would be minimal (the largest difference is only 0.03%). 15.3.22 The predicted dry season SS levels at the indicator points would be in the range of 1.47 to 4.46mg/L. The increases in the SS level caused by the presence of the island would be minimal (less than 1%). Recognising that the WQO requires that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, the difference is considered very small. 15.3.23 The predicted E.coli levels in the dry season ranged from 1 to 232count/100mL that complied with the WQO of 610cfu/100mL. The predicted E.coli level at the Mainland station MR (1count/100mL) also complied with the Mainland standard of 200count/100mL. The island would not cause any changes in E.coli levels at all the indicator points.
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15.3.24 The predicted average dry season UIA (0.00176 – 0.00348mg/L) at all indicator points would be low and well below the WQOs of 0.021mg/L as well as the Mainland standard of 0.02mg/L. 15.3.25 The dry season TIN levels ranged from 0.0476 to 0.0956mg/L that would be very small but the wet season data would be significantly higher. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. The calculated annual mean values ranged from 0.1278 - 0.1549mg/L for NS6-7, SC3-4, 11, MR1, GB6, FP6, SC18 & GT2 (Southern WCZ), 0.119mg/L for FC5 (Eastern Buffer WCZ), 0.0768 - 0.1178mg/L for FP9, SC5-8, FN1a-d, MP4, 8-11, 8b, GT3 and SC12-14, 15, 17, 21 (Mirs Bay WCZ) and 0.0704 – 0.1059mg/L for FC6-11, GB7-10, MP7 & SC16 (Port Shelter WCZ). The annual mean WQO for TIN would be 0.1mg/L for both Southern WCZ and Port Shelter WCZ, and 0.3 and 0.4mg/L for Mirs Bay WCZ and Eastern Buffer WCZ respectively. As a result, exceedances of the annual mean WQO were found at all selected indicator points in the Southern WCZ (NS6-7, SC3-4, 11, MR1, GB6, FP6, SC18 & GT2) as well as Station FC6 in Port Shelter WCZ. It should be noted that the annual mean baseline values predicted at these 11 stations (0.1026 to 0.1546mg/L) also exceeded the relevant WQO of 0.1mg/L. The largest increase caused by the island was found at FP9 of 4.22%. The TIN levels for MF complied with the Mainland standard of 0.3mg/L for both the dry and wet seasons. 15.3.26 According to the wet season water quality modelling results, the predicted 90%ile DO for depth average at the indicator points within Hong Kong waters ranged from 4.27 to 5.50mg/L which complied with the WQO of ≥4mg/L. The predicted depth averaged DO at MF (4.75 – 5.10mg/L) breached the Mainland standard of 5mg/L but the exceedance was not caused by the presence of the island as the baseline values at MF (4.68 – 4.99mg/L) also breached the relevant standard. 15.3.27 For 90%ile bottom DO, the values ranged from 2.33 to 5.19mg/L which complied with the WQO of ≥2mg/L. Meanwhile, the bottom DO at MF (ranged from 3.69 – 4.43mg/L) exceeded the Mainland standard of 5mg/L. However, the baseline value of bottom DO at MF (ranged from 3.56 – 4.29mg/L) also exceeded the Mainland standard. 15.3.28 The predicted average in the wet season salinity ranged from 24.60 to 31.14ppt. Compared to the baseline water quality results, the percentage changes in salinity caused by the presence of the island would be minimal with the largest difference at FP9 of –1.08%. Recognising the WQO requires that change due to any waste discharge should not exceed 10% of natural ambient level, the differences are considered very small. 15.3.29 The predicted wet season SS levels at the indicator points were in the range of 1.76 to 4.63mg/L. The largest increase in the SS level caused by the site was found at GB9 of 17.54%. Recognising the WQO requires that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L, the difference is considered acceptable. 15.3.30 The predicted E.coli wet season levels ranged from 1 to 132count/100mL would be low and well below the WQO of 610cfu/100mL and the Mainland standard of 200count/100mL. 15.3.31 The predicted average wet season UIA (0.00298 – 0.00644mg/L) at all indicator points would be low and well below the WQO of 0.021mg/L and the Mainland standard of 0.02mg/L. 15.3.32 The wet season TIN levels ranged from 0.0674 to 0.2174mg/L which was quite high as compared to the relevant WQO. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. Compliance of the annual mean WQO for TIN is discussed in Section 15.3.25 above.
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Cumulative Impacts 15.3.33 It is understood that a submarine pipeline is soon to be installed through Mirs Bay to carry LPG from Cheng Tou Jiao (northeast Mirs Bay) to the Lamma Island power station. The pipeline will run southwards towards the artificial island site but will veer southwest several km before the site is reached. These works however are due to be complete within two years of commencement and would not give rise to any potential for cumulative effects. 15.3.34 Marine disposal areas and sand borrow pits in the area include the East of Ninepin open sea mud disposal area, the East Tung Lung Chau marine disposal area, sand deposit at South of Victor Rock and Marine Borrow Area at West Po Toi. From generalised information on water currents in the area there is some potential for a cumulative effect on sediment levels in the water column should work at any of these sites be concurrent with dredging or reclamation activities at the artificial island site.
Waste Management 15.3.35 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 15.3.36 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 15.3.37 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 370Mcum • Volume of muds be dredged for outer sea wall: 15Mcum
15.3.38 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 15.3.39 Waste delivery to the site will be by marine vessel, which is preferable in terms of GHG emission. However, as the cumulative distance between marine RTSs and the site is around 450km (referred to the Preliminary Marine Review (March 2002)), the potential GHG emissions could still be moderate.
Ecology Baseline Conditions 15.3.40 The SEOIL is remote, with the nearest landfall being at the Ninepin Group of islands some 12km to the northwest. No marine ecology studies have been identified specifically at the site location, although several studies have been undertaken in waters nearby. Dive surveys indicate that the seabed habitat would likely be dominated by burrowing polychaete worms, with echinoderms and crustaceans also occasionally present. The scavenging gastropod Nassarius siquijorensis was recorded from seabed areas around Basalt Island, and polychaetes dominated the benthic infauna in the same area.2 The disturbed seabed area east of the Ninepin Group is dominated by spionid polychaetes.3 Regular trawling in the broader area has resulted in a uniformly disturbed habitat and, given the consistency in
2 ERM (1997). Seabed Ecology Studies: Basalt Island – Final Report. March 1997.
3 ERM-Hong Kong Ltd (1997d) Seabed Ecology Studies: East of Ninepins Final Report, Civil Engineering Department, Hong Kong Government.
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sediment character and water column depth, benthic community assemblages are not expected to vary much across the general area. 15.3.41 The high value of the coral reef community at the Ninepin Group was documented following the underwater surveys in the area in the early 1990s. The coral communities at Victor Rock some 14km north and at the south coast of Basalt Island some 17km to the northwest are also of high conservation value. These sites are characterised by diverse communities of hard and soft coral, gorgonians, sponges, holothurians, sea urchins, sea fans and fish species. 15.3.42 The marine environment south and west of the Ninepin Group towards the Cape D’Aguilar Marine Reserve, Po Toi and associated islands also supports coral communities of high conservation value. The more open marine waters at the south of this area are habitat to the Black Finless Porpoise Neophocaena phocaenoides, with the waters to east of Po Toi forming part of this species’ core habitat through summer and autumn. 15.3.43 The Green Turtle Chelonia mydas has been observed in coastal waters between Tung Lung Chau, Ching Chau and the Ninepin Group of islands, and is reported to use the waters off southwest Po Toi. Both the Finless Porpoise and the Green Turtle are protected under the Wild Animals Protection Ordinance (Cap. 170) and are listed in CITES Appendix I. Direct Habitat Loss 15.3.44 Around 935ha of benthic habitat and some 20-30m of water column over this seabed area will be lost to the development. Although the area is large, the ecological value of the seabed is not expected to be significant. The loss of water column would be reflected in loss of fisheries habitat. 15.3.45 From available data, the area does not appear to be of particular ecological value to the Finless Porpoise or Green Turtle. However, it is also noted that the site is far from coastal waters and there has been no little study as to the utilization of the area by these species. Water Quality / Hydrodynamics 15.3.46 As the baseline water quality conditions in the area are good, the potential for water quality decline is related to increased suspended sediment / sediment deposition and turbidity during dredging and reclamation works, and the associated potential for decreased dissolved oxygen levels. 15.3.47 Whilst there are no coral communities in the immediate vicinity of the site there is potential for sediment plumes to be transported westwards towards the coastline around Po Toi, Sun Kong and Waglan Island where coral communities of high conservation value exist. Settlement of sediment may occur in more sheltered coastal waters where corals thrive, thereby potentially leading to smothering effects. Likewise, there is some potential for impact on the nearby Cape D’Aguilar Marine Reserve. Given the existing hydrodynamics of the area no impacts upon the coral communities at east Tung Lung Chau, Ching Chau and the Ninepin Group are anticipated. 15.3.48 Modelling predicted that as a worst case scenario (Phase 3 construction wet season;), only a minor elevation (< 0.2mg/L) of suspended solids levels above baseline would occur in the vicinity of the potential island site (FP9). No operational impacts were predicted by the model.
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Marine Vessel Disturbance 15.3.49 From available data, the site area does not appear to be particularly important as a habitat for the Finless Porpoise. However, if marine vessels approach the site via the south of Po Toi group of islands there will be some potential for vessel collision with the Finless Porpoise and possibly the Green Turtle. There would also be greater likelihood for general disturbance from vessel movements through this area (e.g., vessel engine noise and vibration).
Fisheries 15.3.50 The broader the Eastern Waters area is of ecological and commercial fisheries importance, although it is the inland waters between Port Shelter, Tung Lung Chau, Cape D’Aguilar and Po Toi that are by far the most productive.4 This area has been proposed as a fisheries spawning area. The inland waters are an important spawning ground for a number of commercially species, including Apogon quadrifasciatus (broadbanded cardinalfish), Parapristipoma trilineatum (chicken grunt), Sebasticus marmoratus (scorpionfish), Trichiurus haumela, Upeneus sulphureus (sulphur goatfish) and U. tragula (freckled goatfish). Accordingly it is in this area that commercial fishing activities are concentrated. The spawning period for most of the commercially valuable fish species is between June and September. 15.3.51 Port Shelter to the northwest of the site is an important nursery area for P.trilineatum as well as fry and juveniles of the high value red pargo Chrysophrys major and gold lined seabream Rhabdosargus sarba. Commercially valuable species in the South East Hong Kong zone that includes the coastal waters around the Po Toi group of islands include Cynoglossus macrolepidotus (tonguefish) and Pseudosciaena crocea (yellow croaker). 15.3.52 In the offshore waters that are more characteristic of the artificial island site there is still fishing activity, albeit less concentrated. The fisheries value of this area is not known, as fishing effort tends to be concentrated in inland waters, although the area is likely to be of importance for natural fisheries recruitment. 15.3.53 The key concern with respect to fisheries activities is the potential for sediment plume formation and transport from the dredging and reclamation activities towards sensitive areas to the west. In particular, the hydrodynamics for the area indicate that any sediment plume may be carried towards the fisheries spawning area at between Po Toi / Sun Kong and south of Tung Lung Chau. The Tung Lung Chau Fish Culture Zone and the Po Toi O Fish Culture Zones are located approximately 16km to the northwest of the artificial island site and in relatively sheltered waters. No impact on these zones is anticipated. Likewise, the Po Toi FCZ is located on the leeward side of Po Toi Island some 18km west of the site and is not anticipated to be exposed to any sediment plume.
Cultural Heritage 15.3.54 This site is located some distance offshore. There is no immediate evidence of archaeological remains in this area or in the near vicinity. The nearest sites of known archaeological interest are land based, at Tung Lung Chau and Fat Tong Chau, (as discussed in Chapter 12 (East Tung Lung Island Landfill). 15.3.55 Given the remoteness of this site from known land based sites of cultural heritage interest, and the fact that it is not in a area frequented by merchant vessels the likelihood of archaeological remains in this area appear limited. However, given the lack of archaeological data currently available for this site a detailed marine archaeological investigation should be carried out in any future studies.
4 ERM (1998). Fisheries Resources and Fisheries Operations in Hong Kong Waters. For AFCD, Govt. of HKSAR.
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Landscape and Visual 15.3.56 Landscape Planning Designations - This area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 15.3.57 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 15.3.58 Landscape Character - The island landfill site falls within the Eastern Coastal Waters Landscape Character Area (Figure 15.4). The landscape of this part of Hong Kong lies offshore and is an expansive area of open offshore water (Figure 15.3). There are neither islands / landforms in this area nor any major shipping channels in the vicinity of the SEOIL. This means that its character is open, exposed, tranquil and remote. 15.3.59 There exists potential for slight impacts on landscape character resulting from construction/operation works that will introduce new artificial elements that are incompatible with the existing landscape. The character of the island during afteruse will be inconsistent with the natural and tranquil character of the landscape. However, the distance of the island from other landforms will mean that its artificial characteristics will not be unduly emphasised and resulting long-term impact on the landscape character would be slight. 15.3.60 VSRs - VSRs affected by the island landfill are identified in Tables 15.3 and15.4 the extent of the project visual envelopes is shown in Figure 15.5. The island landfill site is approximately 25km from Stanley and Shek O, and the landfill island will have almost no impact on those VSRs. 15.3.61 There are very few VSRs who will see the site from short range. Such VSRs will include visitors to the area for boating, fishing, or other water sports activities. Other VSRs, such as travellers on vessels using the shipping route, are transient. These VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as relatively close artificial elements contrasting with the simple, open and tranquil qualities of the existing landscape. However, given the small number of these VSRs, visual impacts will be insubstantial during both the operation/construction phase and the afteruse phase.
Landfill Gas 15.3.62 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazards. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 15.3.63 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However it will be used as an on-site energy source.
15.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 15.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to Southeast Offshore artificial island site.
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Air Quality 15.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 15.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 15.4.4 No specific water quality mitigation measures are recommended at this site. However, this site is located in a position that is exposed to significant wind and wave action. In the event that they are required, application of mitigation measures such as silt curtains (as described in Part A - Section 5) would prove difficult.
Waste Management / Disposal Impacts 15.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 15.4.6 It is proposed that marine vessel movements are controlled to avoid passage through areas of high Finless Porpoise utilization to the east of Po Toi. Fisheries 15.4.7 There are no particular measures that are proposed for fisheries resource protection. Cultural Heritage 15.4.8 There are no particular measures that are proposed for protection of cultural heritage resources. Landscape & Visual 15.4.9 Landscape and visual mitigation measures are outlined in Part A.
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15.5 Summary 15.5.1 A summary of the SEA for the SEOIL is provided in Tables 15.1 and 15.2: Table 15.1: Southeast Offshore Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within 500m land use of the artificial island site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours would or exacerbate impacts accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant O The site is located in open marine waters to the emissions (TSP (construction), southeastern of the HKSAR waters fringe, with no known NOx, CO, SO2 – LFG Flare) developments that have relevant emissions within 5km taking into account ambient from the site. conditions 5 Total Emissions of Air Pollutants - Waste will be delivered to the site by marine vessel and the from the territory-wide waste cumulative distance to be travelled is estimated to be transportation between the RTSs 450km. and the site 6 Overall Impact O / - Overall air quality impacts is considered to be ‘Neutral / Negative – Low’. This is because local impacts are not anticipated due to the absence of ASRs within 500m from the site but there are potential for regional impacts (from waste delivery).
Noise Assessment
1 Distance to areas of noise O There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the artificial island site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. Therefore, this (Only applicable if there are criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O ‘Neutral’.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O As a marine site, no watercourse diversions are required. 2 Potential for sediment O The sediment in the area has been proved to be contaminant release uncontaminated as part of EPD routine monitoring programme. As such, the potential impact from the release of sediment bound contaminants associated with the dredging work is considered to be limited. 3 Potential impacts on WSRs O / - No WQO exceedances were predicted in the construction phases. Although exceedances in DO and TIN were predicted in the operational phase, their standards were also breached in the baseline scenario and the elevations in DO and TIN in the presence of island were not considered high.
Therefore, the island would not be the cause of the exceedances and the impact is not considered high. 4 Potential Impacts on O A marine site, so there are no groundwater issues. Groundwater 5 Potential Cumulative Impacts O / - Installation of the LPG submarine pipeline through Mirs (Potential for concurrent projects Bay to Lamma Island will be complete before any work to exacerbate preceding starts for the artificial island site. impacts) The site is isolated and the anticipated track of any sediment plume would be to the southeast of the site. As such, whilst there may be concurrent works in the broader area from fill management activities at East of Ninepin, East Tung Lung Chau, South of Victor Rock and / or West Po Toi, the likelihood of cumulative effects on the secondary recreational contact sub-zone around the Po Toi group of islands is remote. 6 Overall Impact O / - The isolation of this site means there is little potential for impact on WSRs to the west. Likewise, although there may be concurrent works with fill management activities in the general area of Eastern Waters, the potential for cumulative effects is considered marginal. Whilst impacts are not anticipated to be significant, the exposed nature of the site could present difficulties in implementing mitigation measures. Overall impact considered to be ‘Neutral / Negative – Low’.
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Impacts Score Commentary
Waste Management Assessment 1 Balance of Materials + The site could accommodate significant amounts of public (surplus/deficit of public fill fill (370Mcum) negating the need to import filling material needed for landfill development) for site formation. Dredged muds will be incorporated with the fill materials within the island footprint. 2 GHG emissions from mode of - Waste will be delivered to the site via marine vessel. The transport for delivery of waste to distance travelled from marine RTS(s) to the site has the site from RTSs been estimated to be 450km. 3 Overall Waste Impact O ‘Neutral’. Overall the site is considered to have neutral impact due to the balance of the benefit of being able to accommodate C&D surplus materials and the relatively larger amount of GHG emissions from the long distance travelled. Ecological Assessment 1 Potential for secondary O The nearest marine based “Area of Absolute Exclusion” is environmental impacts on “Areas the Bluff / Basalt Island SSSI (17km northwest). The of Absolute Exclusion” distance is such that adverse impacts are not anticipated. 2 Affects an important habitat O / - Any sediment plume that may form has the potential to affect pelagic and inter-tidal resources of ecological value around the Po Toi group of islands. These particularly include the coral reef communities at the Cape D’Aguilar Marine Reserve and Po Toi, Beaufort Island, Sun Kong Island and Fury Rocks. The open waters around the artificial island site are habitat to fishes and possibly the Finless Porpoise and Green Turtle, albeit not a significant one. 3 Affects a species of conservation O / - The Finless Porpoise and the Green Turtle have both importance been observed in the broader area, although sightings suggest that neither species has any significant use of the waters within and adjacent to the site. 4 Potential for Cumulative O / - Installation of the LPG submarine pipeline through Mirs Ecological impacts on sites of Bay to Lamma Island will be complete before any work recognised value starts for the artificial island site.
The site is isolated and the anticipated track of any sediment plume would be to the southeast of the site. As such, whilst there may be concurrent works in the broader area from fill management activities at East of Ninepin, East Tung Lung Chau, South of Victor Rock and / or West Po Toi, the likelihood of cumulative effects on ecological receivers around the Po Toi group is slight. 5 Overall Ecological Impact O / - There is marginal potential for impact under each of the evaluation criteria, and hence ‘Neutral / Negative – Low’ overall.
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Impacts Score Commentary
Fisheries Assessment 1 Potential for secondary O / - There is a Fisheries Protection Area (FPA) and an environmental impacts on “Areas artificial reef (AR) deployment area at Port Shelter. The of Absolute Exclusion” potential for any sediment plume to be carried towards this area is remote given the distance and the hydrodynamics across the area. 2 Affects an important mariculture - The site is not an important spawning or nursery ground, / fisheries resources (including but any sediment plume that may form could be spawning / nursery ground) transported west of the site and through an important spawning area for commercially valuable fish species. 3 Potential for Cumulative O / - As with ecology, there would be potential for adverse Fisheries Impacts on sites of cumulative impacts (sediment induced) should concurrent recognised value fill management related marine works be in progress. 4 Overall Impact O / - There is potential for adverse impact on the fisheries spawning area west of the site, and marginal potential for impact upon the FPA and AR deployment area at Port Shelter. The cumulative impact potential is marginal, so overall: ‘Neutral / Negative – Low’. Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage significance. Deemed or Graded sites) / archaeological sites 2 Potential for archaeological - The site is remote from land based archaeological sites value with links to maritime activities. Notwithstanding the lack of archaeological data currently available at the site, it is considered that the likelihood of archaeological remains in this area is low. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O There are no planned or confirmed projects, which may Heritage Impacts on sites of cause cumulative heritage impacts. recognised value 4 Overall Impact O ‘Neutral’. The potential impacts on cultural heritage are considered to be negligible. The site is remote from land based archaeological sites with links to maritime activities. A detailed marine archaeological investigation should be carried out in any future studies.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts will therefore be Neutral.
2 Impacts on Landscape O As the site lies in a marine area, there are no impacts on Resources landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - Construction and operation of the island will contrast with Character the simple, open and tranquil qualities of the area. Once completed, the afteruse mitigation will reduce the overall impact of the island somewhat. The absence of any surrounding landforms will serve to mitigate the artificial qualities of the island landform. Overall resulting impacts on landscape character will be Negative – Low. 4 Overall Visual Impacts - The number of VSRs affected by the island landfill is very few and most are so distant (over 20km) that the island would not affect them. The most affected VSRs are a very limited number of recreational VSRs that use the area for passive and active recreation. Generally therefore, visual impacts will be Negative – Low. 5 Overall Impact - Overall, landscape and visual impacts will be ‘Negative – Low’ for the following reasons: • There are no landscape designations covering the disposal site; • No significant landscape resources are affected; • The open, natural and isolated landscape character of the Eastern Coastal Waters will be slightly compromised; • There are very low numbers of residential VSRs within the visual envelope of the site and an extremely small number close to it.
Landfill Gas Assessment 1 Distance between the new / O The nearest sensitive receivers are >250m from the site. extended landfill and SRs 2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. the LFG Consultation Zone) 3 Man Made/Natural Pathways for O None. LFG Migration 4 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce Greenhouse Gas use) Emissions 5 Overall Landfill Gas Impact O ‘Neutral’.
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Table 15.2: Summary of Southeast Offshore Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O / - Neutral / Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact O / - Neutral / Negative – Low Overall Waste Management Impact O Neutral Overall Ecological Impact O / - Neutral / Negative – Low Overall Fisheries Impact O / - Neutral / Negative – Low Overall Cultural Heritage Impact O Neutral Overall Landscape & Visual Impact - Negative – Low Overall Landfill Gas Impact O Neutral
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Table 15.3 Assessment of Significance of Visual Impacts for Southeast Offshore Island Landfill During Construction / Operation Phase for SE Offshore Island Landfill (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Construction / Medium, High) before Mitigation (Insubstantial, and Source(s) only) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential Receivers VR65 Stanley 25km Many Negligible Low Insubstantial Insubstantial Recreational Receivers VR68 Shek O 21km Many Negligible Medium Insubstantial Insubstantial VR69 Clear Water Bay 21km Many Negligible Medium Insubstantial Insubstantial VR71 Leung Shuen Wan Chau (High 30km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 25km Very Few Small Medium Moderate to Slight Insubstantial Diving and other Water sports (Varies) activities Travelling Receivers VR49 On Vessels using the Shipping 0.5 – 25km Very Few Small Low Slight Insubstantial Lanes (Varies)
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Table 15.4 Assessment of Significance of Visual Impacts for Southeast Offshore Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of Magnitude of Receptor Impact Significance of No. of Receiver (VSR) Distance Receivers (order Impact During Sensitivity (Low, Significance Residual Impacts VSR Between VSR of magnitude Afteruse Medium, High) before Mitigation (Insubstantial, and Source(s) only) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential Receivers VR65 Stanley 25km Many Negligible Low Insubstantial Insubstantial Recreational Receivers VR68 Shek O 21km Many Negligible Medium Insubstantial Insubstantial VR69 Clear Water Bay 21km Many Negligible Medium Insubstantial Insubstantial VR71 Leung Shuen Wan Chau (High 30km Few Negligible Medium Insubstantial Insubstantial Island) VR11 Area for Boating, Fishing, 0.5 – 25km Very Few Small Medium Moderate to Slight Insubstantial Diving and other Water sports (Varies) activities Travelling Receivers VR49 On Vessels using the Shipping 0.5 – 25km Very Few Small Low Slight Insubstantial Lanes (Varies)
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16. LAMMA NORTH ISLAND LANDFILL 16.1 Basic Information Project Title 16.1.1 Lamma North Island Landfill (LNIL) – marine site M.11. Nature of Project 16.1.2 The Project would form a new marine based waste disposal site in waters located off the northwest of Lamma Island (Figure 16.1). 16.1.3 The project would require the construction of an artificial island of approximately 435ha. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 16.1.4 The LNIL is located approximately 0.6km to the north of Lamma Island and 1.1km from the HEC Lamma Power Station at the nearest point within the West Lamma Channel waters. Approximately 125Mcum of fill material will be required to construct the artificial island, with a final site formation level to +6mPD. The capacity of the landfill site would be approximately 85Mcum. 16.1.5 Seabed levels in this area are in the range 7 to 8m below Chart Datum. There would be no apparent need for dredging works to develop the site.
History of Site 16.1.6 The LNIL is located off the northwest coast of Lamma Island and would be entirely formed as part of this project. The site falls within the Hong Kong Island South & Lamma Island Planning and Development Study, and is on the boundary of the South West New Territories Development Strategy Review area. The site area currently includes designated shipping anchorages at “North Lamma” and “North West Lamma”. 16.1.7 There has been no previous development activity within the site. Coastal reclamation works have been undertaken for the existing Lamma Power Station that is located south of Yung Shue Wan, Lamma. There are also ongoing works to extend this Power Station, including reclamation activities slightly south into Ha Mei Wan. A Feasibility Study for siting a Waste-to- Energy Incineration Facility (WEIF) adjoining the south of the Lamma Power Station extension site has been completed. It is understood that a more detailed site selection study is presently being conducted on behalf of EPD.
Number and Types of Designated Projects covered 16.1.8 The LNIL would qualify as a Designated Project under the five categories listed in Part A; Section 2.1. 16.2 Outline Of Planning and Implementation Programme 16.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 16.2. Assuming landfill operations start in 2018, LNIL would be full during the period 2030 to 2035, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 16.2.2 The site is currently not covered by any statutory town plans. As described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 16.2.3 This site falls within the boundary of the South West New Territories Development Strategy Review. No recommendations for this area were made under this strategy.
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16.2.4 The Recommended Development Strategy formulated under the South West New Territories Development Strategy Review identified the potential of Cheung Chau and Lamma as tourist and recreation developments; this recognised their mountain scenery, appealing coastal areas and the large number of archaeological and historical sites. 16.2.5 Lamma Island lies to the south of this site and is covered by the Lamma Island OZP Plan no. S/I – LI/3 issued in October 2001. The general, planning intentions of the Lamma Island OZP are to conserve the natural landscape, the cultural heritage, the rural character and the car- free environment of Lamma Island; and to enhance the role of Lamma Island as a leisure destination. The Island has been subject to further investigation under the Planning and Development Study on Hong Kong Island South and Lamma Island. 16.3 Possible Impacts on the Environment 16.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the LNIL are outlined below. Figure 16.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 16.1 and 16.2.
Air Quality 16.3.2 The LNIL development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation; • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.); and • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
16.3.3 There are Air Sensitive Receivers (ASRs) found within a 500m radius from the boundary of this site, with the closest being a number of village houses in Pak Kok San Tsuen that is some 400m southeast of the site boundary. There are other ASRs located along the shoreline of Yung Shue Wan approximately 0.6km from the site boundary. 16.3.4 The existing HEC Lamma Power Station is located approximately 1.1km from the site boundary. The HEC’s air quality monitoring programme at Pak Kok San Tsuen shows that levels of sulphur dioxide and nitrogen dioxide did not exceed the relevant AQOs in year 2000.1 16.3.5 For the operational landfill, as the site lies in an open marine area (i.e., no airshed) there would not be any accumulation of air pollutants. 16.3.6 Marine vessel will be the mode of transportation for waste delivery to the site. The amount of air pollutants emitted from the territory-wide waste delivery to the site will be less compared to a land based site that relies on road transport. The estimated cumulative distance to be travelled from the existing and planned marine RTSs to the site is approximately 200km. Given the likely distance to be travelled and the benefit of the using marine transport, the regional impacts from waste transportation are considered to be insignificant.
Noise 16.3.7 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities;
1 EPD (2001). Air Quality in Hong Kong 2000. Air Services Group, Environmental Protection Department, HKSAR Govt.
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• Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc.
16.3.8 There are no NSRs within 300m of the LNIL site; the nearest NSRs are located at Pak Kok San Tsuen, approximately 400m to the southeast. Whilst the distance separation should significantly attenuate noise propagation, the effectiveness (compared to attenuation over a similar distance on land) would be diminished due to the lack of topographical features, vegetation etc. The extent of any noise impacts arising from reclamation, operation and construction of the landfill would be dependent upon the plant, programme and general scale of works. The acceptability of impacts would need to be confirmed during an EIA. 16.3.9 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. The Area Sensitivity Rating for the village area is “A” and so the permissible night time noise limit is 45dBA. As such there is some potential for adverse noise impact should night time works take place. 16.3.10 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 16.3.11 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 16.3.12 The site would fall wholly within the Southern Water Control Zone (WCZ) although impacts upon water quality may potentially also extend to waters within the Western Buffer WCZ due west of the site. EPD conducts routine marine water quality monitoring at two locations in proximity to the artificial island site: SM7 in the Southern WCZ to the south and WS1 in the Western Buffer WCZ to the west, with sediment quality monitoring stations at the same locations – SS4 to the south and WS2 to the west. 16.3.13 Marine waters in the area are influenced by nitrogen and phosphorus discharges from the Pearl River, with nutrient levels generally declining along a north-south gradient in the West Lamma Channel.2 Due to this influence there was non-compliance with the WQO for total inorganic nitrogen (TIN) at station SM7 in the year 2000, although there was full compliance with the WQOs for dissolved oxygen and un-ionised ammonia. There is a long-term trend of increased TIN in Ha Mei Wan that may also be due, at least in part, to the relatively low water current in this bay area and the influence of the Pearl River discharge. Water quality around station WS1 is similar to that at SM7 although there was full compliance with the WQO for TIN in the year 2000 due to a higher objective (0.4mg/L compared with 0.1mg/L as at SM7). 16.3.14 EPD data also shows marine sediment quality to be good in the area, with only levels of silver exceeding the Lower Chemical Exceedance Level at WS2 and no LCEL exceedance at SS4. Key Issues and Sensitive Receivers 16.3.15 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and
2 EPD (2001). Marine Water Quality in Hong Kong in 2000. EPD, Government of the HKSAR – 2001.
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• Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns).
16.3.16 A number of Water Sensitive Receivers (WSRs) are present in the vicinity of the site. These include:
• Cooling water intake for HEC Lamma Power Station; including New Extension intake; • Seawater intakes (flushing) at Western District and Ap Lei Chau; • Seawater intake (cooling) at Pok Fu Lam; • Gazetted beach near the Power Station at Hung Shing Ye; • Gazetted beach at Lo So Shing; and • Secondary contact recreation sub-zone along north and west Lamma coastline.
16.3.17 In addition, there are a range of aquatic and inter-tidal ecological receivers within the vicinity of the site that may be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the “Ecology” and “Fisheries” subsections. The sensitive receivers include:
• Coral community at Shek Kok Tsui, northwest Lamma; • Coral and Green Turtle habitat near Boulder Point (Pak Kok), northeast Lamma; • Coral community at Green Island; • The western / southwestern waters of the proposed South Lamma Marine Park; and • Lo Tik Wan Fish Culture Zone.
16.3.18 The area around the site coincides with the approximate northern habitat boundary of the Black Finless Porpoise, Neophocaena phocaenoides. From sightings data, it is known that the Finless Porpoise move into the waters of West Lamma in December and reach their peak abundance around southwest Lamma between March and May.3 16.3.19 The locations and uses of these sensitive receivers are shown in Figure 16.1. Reclamation and Site Formation 16.3.20 During reclamation and site formation activities, sediment handling may lead to adverse water quality impacts from increased suspended solids and reduced dissolved oxygen levels. There is also potential for sediment plumes to form and be dispersed by the prevailing current, although from a review of generalised current pattern data for the area it would seem that the currents in the area are not strong. 16.3.21 The placement of fill for island construction is likely to lead to localised increases in suspended solid levels. The hydrodynamic and water quality modelling indicated that WQO exceedence would occur at SC1 (33.59%) in the dry season and at SC20 in both the dry (80.00%) and wet (38.66%) seasons during Phase 1 construction. Increased levels of SS were also predicted in the Phase 1 construction dry season at WI3 (16.94%), FC3 (24.51%), WI2 (15.11%), NS9 (18.51%) and NS8 (16.55%). In the Phase 2 construction WQO exceedence was predicted at SC1 (32.68%) and SC20 (70.35%) in the dry season. Increased levels of SS were also predicted in the Phase 2 construction dry season at W13 (15.16%), FC3 (21.74%) and NS9 (16.83%) and in the wet season at SC20 (28.01%). In the Phase 3 construction, WQO exceedence were predicted in the dry season at SC1 (42.41%) and FC3 (32.65%) and in both the dry and wet season at SC20 (161.18% and 85.91% respectively). Increased levels of SS were also predicted at WI3 (17.38%), WI2 (16.22%), NS9 (21.63%) and NS8 (17.99%).
3 AFCD (2001). Finless Porpoise: Distribution & Abundance [http://www.afcd.gov.hk/con_new/fin_distri4.htm].
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Hydrodynamic and Water Quality Impacts Following Island Formation 16.3.22 Hydrodynamic modelling showed that locating an island at North Lamma could reduce the cumulative flow significantly at East Lamma (approximately 17% in both seasons), West Lamma (29.84% in the wet season) and Tathong Channels (14.87% in the wet season). Although the site would be located approximately 400m off the northwest Lamma coastline with water depths between the island site and the coast of between 6 and 10m, the impact on water sensitive receivers to the north/northwest of Lamma Island would not significant. The flow velocity is predicted to increase significantly in the area to the north of the island during the wet season spring ebb tide. The overall current magnitude is predicted to increase by 29.18% and 4.44% to the west and east of the island respectively. 16.3.23 In the hydrodynamic and water quality modelling, 13 sensitive receivers that are close to the site were selected for presentation. Of the 13 chosen indicator points, 7 are located in the Southern WCZ (FP8, NS9, NS8, SC20, CW4, FC4, FC3), 3 in the Victoria Harbour WCZ (CW6, CW5, WI3) and 3 in the Western Buffer WCZ (CW3, WI2, SC1). 16.3.24 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 5.13 to 7.32mg/L which complied with the WQOs of ≥4mg/L for depth-averaged DO and ≥2mg/L for bottom layer DO. Compared to the baseline water quality results, the percentage differences in DO caused by the presence of the island were minimal (less than 2.1%). 16.3.25 The predicted average dry season salinity ranged from 33.75 to 33.99ppt. Compared to the baseline water quality results, the island would reduce the salinity at a number of indicator points. The differences in salinity levels were minimal (less than 1%) at all of the selected indicator points as compared to the WQO requirements that change due to any waste discharge should not exceed 10% of natural ambient level. 16.3.26 The predicted dry season SS levels indicated points were in the range of 3.60 to 5.73mg/L. The predicted differences caused by the presence of the island ranged from 0.2 to 3.26%. Comparing to the WQO requirements that any waste discharge should not raise the natural ambient level by 30%, these differences are considered very small. 16.3.27 The predicted E.coli levels in the dry season ranged from 1 to 4,060count/100mL. Only CW6 with the E.coli levels of 4,060count/100mL exceeded the WQO of 610 cuf/100ml but the baseline value predicted at this station (4,097count/100mL) also exceeded the WQO. The predicted E.coli levels at all other stations are significantly lower (ranged from 1 to 287count/100ml). 16.3.28 The predicted average dry season UIA (0.00258 – 0.01418mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L for annual mean. 16.3.29 The dry season TIN levels ranged from 0.0724 to 0.563mg/L. Since the WQO of TIN is an annual mean value, the predicted mean TIN levels for both the dry and wet seasons were averaged to represent the annual mean values. It was found that all indicator points in the Southern WCZ (SC1, CW4, FC4, NS8, NS9 and SC20) breached the annual mean WQO of 0.1mg/L but the averaged baseline values at these stations also exceeded the WQO. The percentage increases in the annual mean TIN values caused by the island were less than 5.1% at these stations. 16.3.30 According to the water quality modelling results for the wet season, the predicted 90%ile DO for depth averaged and bottom layers ranged from 4.89 to 6.37mg/L which comply with the WQO of ≥4mg/L for depth-averaged DO and ≥2mg/L for bottom layer DO. Compared to the baseline water quality results, the percentage differences for 90%ile depth-averaged DO and bottom DO were small (less than 2%). 16.3.31 The predicted average wet season salinity ranged from 20.07 to 24.93ppt. Compared to the baseline water quality results, the largest difference was found at WI2 of 5.79%. The difference is considered small as compared to the WQO of 10%.
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16.3.32 The predicted wet season SS levels at the indicator points were in the range of 4.84 to 6.84mg/L. It is predicted that the island would increase the SS level at most of the indicator points. The largest increase in SS levels was predicted at SC20 with percentage difference of 1.89% which is considered small as compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30%. 16.3.33 The predicted E.coli levels in the wet season ranged from 1 to 3,729count/100 mL. Only CW6 with E Coli levels of 3,729count/100mL exceeded the WQO of 610 cuf/100ml but the baseline value predicted at this station (3,743count/100mL) also exceeded the WQO. The predicted E.coli levels at all other stations were significantly lower (ranging from 1 to 307count/100ml). 16.3.34 The predicted wet season UIA (0.00406 – 0.00689mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L. The predicted UIA levels would increase at most of the indicator points with the percentage increase of 0.16% to 1.98%. 16.3.35 For predicted wet season TIN levels, the values were high and ranged from 0.230 to 0.3031mg/L. It is predicted that the presence of the island would increase the TIN levels at most of the indicator points. Non-compliance of the annual mean WQO was found at all the indicator points in Southern WCZ (SC1, CW4, FC4, NS9, NS8 and SC20) as discussed in Section 16.3.29. 16.3.36 The modelling results also indicated that the water quality impacts due to the site on Sea Water Intakes were minimal. The pollutant levels at WI2 (WSD Sea Water Intake at Ap Lei Chau) and WI3 (WSD Sea Water Intake at Kennedy Town) complied with the WQO of Sea Water for Flushing Supply. Cumulative Impacts 16.3.37 The capacity of the existing HEC Power Station on Lamma is presently being increased. The EIA Study for the Lamma Power Station Extension that was completed in 1999 assumed that the first of the six 300MW gas-fired units of the extension will be operational by 2003, with the fifth and sixth commissioned during 2012.4 This project would involve a southward extension of the existing site into the northern end of Ha Mei Wan. The reclamation would be complete before 2010 – the earliest commencement date for development activities for the LNIL. 16.3.38 The Feasibility Study completed for the siting of a potential Waste-to-Energy Incineration Facility (WEIF) at Lamma indicated that commissioning of the facility would be five years after the start of initial reclamation works. The reclamation area would cover a maximum area of 17ha and reclamation and dredging works for a seawall and breakwater would last for approximately one year.5 The EIA Study for the Lamma Power station extension concluded that there would be insignificant impacts on water quality / circulation patterns from the extension alone and from the combined Power Station extension and potential Waste to Energy Incineration Facility (WEIF) at Lamma. 16.3.39 Ultimately siting of a WEIF at Lamma was not recommended on environmental grounds (ibid.). Although there are ongoing studies for the development of a “waste to energy facility” for the HKSAR, for the purpose of this assessment it is assumed that any future facility would not be located at Lamma Island. As such, there is no potential for cumulative hydrodynamic / water quality impacts.
4 ERM (1999). EIA Study for 1,800 MW Gas-fired Power Station at Lamma Extension. Hongkong Electric Co. Ltd.
5 CDM (1998). Feasibility Study of Waste-to-Energy Incineration Facilities: Site Assessment Report – Lamma Island. Submitted to EPD, July 1998.
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Waste Management 16.3.40 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 16.3.41 Various options for construction have been explored for this site and it is anticipated that muds would not need to be excavated to facilitate construction of the outer seawall, prior to public filling. Upon completion of construction, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 16.3.42 Anticipated volume of materials are as follows:
• Volume of public fill that could be accepted for island construction: 125Mcum
16.3.43 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 16.3.44 Waste will be delivered to the LNIL by marine vessel only. This will have the benefit of lowering the GHG emission per kg waste handled compared to delivery by road vehicle. Besides, the cumulative distance to be travelled (between marine RTSs and the site) is around 200km (referred to Preliminary Marine Review (March 2002)), the impacts associated with the GHG emissions are considered to be neutral.
Ecology Baseline Conditions 16.3.45 Data and information on aquatic resources in the area is available from the EIA Study Report on the HEC Power Station Extension. The EIA summarised the findings of past survey work on the benthic infauna for the general environs around the Lamma Power Station. Amongst the most relevant studies summarised were data from grab-sampling work undertaken in 1991 / 92 for the EIA for the Lantau Port and Harbour Development Study. This data showed the infauna community to be dominated by polychaete worms, whilst overall infauna community diversity and biomass was greater during the dry season survey than the wet season survey.6 16.3.46 A similar pattern of dominance was discovered from grab sampling conducted for the Lamma Power Station Navigation Channel and Jetty Modification Works Study in 1994, with molluscs and crustaceans also abundant in the benthic community. From a review of data from various locations across the HKSAR, it appears that benthic community biomass in the vicinity of the Power Station and the LNIL is relatively low (ERM, 1999). 16.3.47 Inter-tidal resources on the northwest Lamma Coastline were also investigated under the HEC Power Station Extension study and are reportedly characterised by molluscs and crustaceans. The most abundant fauna species included the Chiton Acanthopleura japonica, the Snail Nodilittorina trochoides, the Barnacle Balanus amphitrite and particularly the Limpet Patelloida saccharina.
6 APH Consultants (1992). Lantau Port and Harbour Development Study: Marine Baseline Studies. Submitted to CED, HKSAR Government. October 1992.
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16.3.48 The encrusting hard coral Psammocora superficialis and small colonies of the family Faviidae were also observed along the northwest Lamma coast around Shek Kok Tsui. The coral density at this site was reported as 1.67% and is not of conservation importance. In contrast the density of the community of soft corals and gorgonians in the shallow sub-tidal waters around Pak Kok, northeast Lamma, is in the order of 13%. The Pak Kok community is of conservation significance.7 There are also hard corals of some conservation significance around the coast of Green Island, some 6km north of Lamma Island 16.3.49 The Green Turtle Chelonia mydas – one of 3 species of sea turtles found in Hong Kong – has also been observed in waters around Pak Kok. So far the Green Turtle is the only turtle species known to breed locally, with nesting only reported thus far at the sandy beach at Sham Wan, south Lamma.8 The Green Turtle is protected under the Wild Animals Protection Ordinance, Cap.170. 16.3.50 Observations of the Black Finless Porpoise in the area of the site are limited to occasional sightings made during the period September to May. Data on seasonal abundance and distribution for this species gives peak abundance during March to May. By the summer (June through August) the species has moved from West Lamma waters to the south and southwest waters – apparently coinciding with intrusion by the Chinese White Dolphins – and by autumn (September to November) species abundance in Hong Kong waters is at a low point. The species moves back into the waters of Lamma and South Lantau from December.9 From observations data collated by the AFCD, the core area for this species is in the costal waters off southwest Lamma. 16.3.51 Fisheries resources of ecological significance in the area are present south of Cheung Chau and south of Lamma Island. These areas are important spawning and nursery grounds for a range of fish and crustacean species.10 These waters also support the squid Loligo sp., the lion-head fish Collichthys lucida and the tiger-tooth croaker Otolithes argenteus that comprise the most common and numerically important prey species of the Finless Porpoise.11 Direct Habitat Loss 16.3.52 The site footprint covers a surface area of 435ha. The site area is entirely sub-tidal and its benthic community is dominated by common polychaetes, with molluscs and crustaceans also abundant. Whilst the exact island location has not been investigated, it is not expected that there are benthic species of ecological significance in the area. 16.3.53 Distribution data for the Black Finless Porpoise shows that this species is seasonally observed off northwest Lamma, and that these waters appear not to be a key habitat area. However, this species is relatively shy and elusive compared to the Chinese White Dolphin and tends not to socialize in surface waters as much (Jefferson, 2001). As such, there is some potential that it may be more abundant in the immediate environs of the site than field observations alone would suggest.
7 Binnie Consultants Ltd. (1995). Fill Management Study – Phase IV. Marine Ecology of Hong Kong: Report on Underwater Dive Surveys. Volume I, January 1995.
8 AFCD (2001). AFCD Website. Conservation: Protection of Green Turtles. [www.afcd.gov.hk/con_new/turtle.htm]. 9 AFCD (2001). AFCD Website. Conservation: Finless Porpoise. [www.afcd.gov.hk/con_new/finpor.htm].
10 ERM (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to AFCD, HKSAR Govt.
11 Jefferson, T.A. (2001). Conservation Biology of the Finless Porpoise in Hong Kong Waters. Submitted to AFCD, HKSAR Government.
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Water Quality / Hydrodynamics 16.3.54 Any deterioration in water quality would drive fish from the area due to their sensitivity to increased suspended sediment levels, resulting in reduced feeding opportunities for the Finless Porpoise in these waters. However, as the site is not a key area for the Finless Porpoise, the significance of a decline in water quality would not be expected to be greatly significant. 16.3.55 The model predicts that suspended solids levels around the small sub-tidal coral community at Shek Kok Tsui, northwest Lamma would increase by 1.8mg/L over the baseline to around 6mg/L under the Phase 3 construction dry season. Sediment levels at the ecologically valuable coral community at Pak Kok are predicted by the model to increase significantly by 7mg/L to around 11mg/L under the same scenario. It is noted that the Green Turtle has been observed in these waters. The model does not predict an adverse effect on the hard coral communities around Green Island. Whilst the exact effects of increased suspended sediment upon sedentary species such as the corals at Pak Kok cannot be predicted, they may potentially be increased stress brought about by decreased sunlight penetration that would affect photosynthesis or a change in localised sedimentation affecting filter feeding. Effects on motile species would most likely be insignificant due to their ability to actively avoid certain areas at certain times. 16.3.56 The northern boundary of the proposed South Lamma Marine Reserve / Park is some 5km south of the artificial island site. Whilst there is potential for sediment transport towards this area on the ebb tide, the current strengths are not considered great enough to carry suspended sediment this far (assuming standard control measures are in place during reclamation works). Likewise, due to the distances involved and the strengths of the water current it is not considered that any deterioration in water quality would be localised around the North Lamma area and would not affect the Finless Porpoise habitat or the important fisheries areas at South Cheung Chau and South Lamma. Marine Vessel Disturbance 16.3.57 From a study conducted on behalf of the AFCD, it is known from data on strandings of Black Finless Porpoise specimens that vessel collision is a significant cause of death (Jefferson, 2001). The increase in marine traffic required for site formation / reclamation activities and operational marine traffic could potentially lead to an increase in incidences of vessel collision.
Fisheries 16.3.58 The LNIL is located around the delineation of three fishing zones: Pak Kok (zone 0096), Po Lo Tsui (0097) and West Lamma Channel (0109). The Ha Mei fishing zone is located to the southeast. Available data indicates that Ha Mei is the most popular area in terms of the number of fishing vessels utilizing the zone, although on a unit area basis Po Lo Tsui is the most productive zone for both adult and fry fish, ranking 43rd of 210 zones and 39th of 89 zones respectively. In terms of value ranking, Po Lo Tsui is 27th of 210 zones, with Pak Kok, West Lamma Channel and Ha Mei ranking 128th, 113th and 70th respectively (ERM, 1998). 16.3.59 Commercially important species (adult fish) caught in the area are the Yellow Croaker Pseudosciaena crocea at Pak Kok and Po Lo Tsui, and the Mantis shrimp Oratosquilla spp. around Ha Mei (ibid.). The catch of low value pelagic species such as scad Caranx spp. and sardine Sardinella jussieui is also high in these areas. Overall, the development of the artificial island may have an adverse impact on fisheries resources in the Po Lo Tsui due to the small area and relatively high productivity of this zone. Impacts on the other nearby zones would not be expected to be significant given their relatively low productivity / commercial value, and general distance from the works area. 16.3.60 It is predicted by the numerical model that there may be a small increase in suspended solids levels at Lo Tik Wan fish culture zone (FC3) by less than 1.5mg/L above baseline to around 5.5mg/L during the dry season, Phase 3 construction.
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Cultural Heritage 16.3.61 There is no immediate evidence of archaeological remains in this area. However there are a significant number of archaeological sites on both Lamma and Cheung Chau. The presence of sites on land strongly suggests that seafarers would have used the natural harbours of the islands and the waters around the site for several thousand years. 16.3.62 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site, a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 16.3.63 Landscape Planning Designations - This area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 16.3.64 Landscape Resources - The site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources. 16.3.65 Landscape Character - The site is located in the West Lamma Channel LCA, approximately 1km off the northwest coast of Lamma Island. The character of the area is open with some sense of containment provided by the outlying islands of Cheung Chau, Peng Chau and further on to Lantau Island which frames the area (Figures 16.3 and 16.4). There is a strong relationship between these outlying islands. The area is relatively undisturbed by major shipping although ferries to outlying islands, PRC and Macau regularly pass through the area providing some variation in visual character. 16.3.66 Construction/operation works will introduce new artificial elements which are incompatible with the existing natural characteristics of the landscape, resulting in substantial impacts on landscape character. During the afteruse phase of the island landfill, these impacts are likely to be reduced somewhat, as the completed island is restored. By virtue of its proximity to Lamma, the island will however contrast unfavourably with the natural landforms of Lamma Island. As a consequence of this, the long-term impact on landscape character will be moderate to substantial. 16.3.67 VSRs - VSRs affected by the proposals are identified in Table 16.3 and 16.4. The extent of the project visual envelope is shown in Figure 16.5 and the key views to the site are shown in Figure 16.6. 16.3.68 The close proximity of the island to Lamma and Hong Kong Islands results in a number of residential VSRs being very significantly impacted upon by the site. Of note, is the large number of residential VSRs in Yung Shue Wan on Lamma Island and on Hong Kong Island who will experience high levels of visual impact. The occupational VSRs at the Lamma Power Station will also be affected as well as a number of recreational VSRs on Hong Kong Island, Cheung Chau and Lamma. A significant number of travelling VSRs will also be affected, including those in vessels and ferries using the shipping lanes. 16.3.69 These VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as relatively close artificial elements contrasting with the open and natural qualities of the existing landscape. Resulting visual impacts will be substantial to moderate. After the restoration of the landfill island, its visual impact will be reduced somewhat during the afteruse phase, with the exception of VSRs located close to the site, such as Yung Shue Wan who will lose their views of the West Lamma Channel and Lantau. Generally, residual visual impacts for VSRs will be as moderate to substantial.
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Landfill Gas 16.3.70 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 16.3.71 There may be some potential for use of LFG as an energy source for surrounding communities at Lamma North, or possibly the Lamma Power Station. In any event LFG could be used as an on-site energy source. 16.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 16.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to the site.
Air Quality 16.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Noise 16.4.3 No specific noise mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Water Quality 16.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the artificial island reclamation. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Waste Management 16.4.5 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Ecology 16.4.6 As a precaution, given the anticipated elevated limits of SS, water quality mitigation measures should be implemented to protect sensitive ecological SRs such as the coral reef community around Pak Kok, northeast Lamma.
Fisheries 16.4.7 No special measures are proposed to protect fisheries resources.
Cultural Heritage 16.4.8 No special measures are proposed to protect cultural heritage resources. Landscape & Visual 16.4.9 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A and are illustrated in Figure 16.8.
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16.5 Summary 16.5.1 A summary of the SEA for the LNIL is provided in Tables 16.1 and 16.2:
Table 16.1: Lamma North Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air - A small number of village houses in Pak Kok San Tsuen sensitive land use are within 500m of the site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours would or exacerbate impacts accumulate around the site. 3 Occurrence of meteorological O Wind blows both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant - The site is located in an open marine area. HEC Lamma emissions (TSP (construction), Power Station is located approximately 1.1km from the NOx, CO, SO2 – LFG Flare) site. Emissions from the Power Station may already taking into account ambient contribute a considerable portion of the ambient conditions condition. 5 Total Emissions of Air O Waste will be delivered to the site by marine vessel and Pollutants from the territory- the cumulative distance to be travelled is estimated to be wide waste transportation 200km. between the RTSs and the site 6 Overall Impact - ‘Negative – Low’. Given the fact that ASRs are located within 500m from the site and there are potential for cumulative impacts from the HEC Lamma Power Station.
Noise Assessment
1 Distance to areas of noise - There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the site. However, at night time the BNL for the village area is reduced to 30dBA and so potential for adverse impacts exists. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (Only applicable if there are Therefore, this criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O / - ‘Neutral / Negative – Low’.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial island. Not relevant. 2 Potential for sediment O The sediment in the vicinity of the North Lamma artificial contaminant release island is not contaminated, and so there is no potential for contaminant release. 3 Potential impacts on WSRs - - Generalised current pattern data indicates that there is (including increase or little potential for impacts upon WSRs in north Ha Mei exceedance of WQO) Wan. However, there is greater potential for impacts upon the beach and secondary contact sub-zone in mid and southern Ha Mei Wan, including a potential decrease in flushing within the Bay area. WQO non-compliance was predicted at various nearby areas included the surveyed coral and Green Turtle sites at north Lamma. 4 Potential Impacts on O Artificial island. Not relevant. Groundwater 5 Potential Cumulative Impacts O There are no anticipated cumulative impacts as the Lamma Power Station reclamation works will be complete, whilst the proposed WEIF site has not been recommended on environmental grounds. 6 Overall Impact - There is potential for adverse water quality impact on a number of WSRs in the Ha Mei Wan area including the secondary contact recreation sub-zone and popular bathing beaches. However, as impacts are not anticipated for the other evaluation criteria the overall likelihood is ‘Negative – Low’. Waste Management Assessment
1 Balance of Materials + The site could accommodate a significant amount of (surplus/deficit of public fill public fill (125Mcum), thus negating the need to import needed for landfill development) filling material for site formation. This site will not require the dredging of any muds. 2 GHG emissions from mode of O Waste will be delivered to the site via marine vessel. The transport for delivery of waste to distance travelled from marine RTSs to the site has been the site from RTSs estimated to be 200km. 3 Overall Impact + ‘Positive’.
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Impacts Score Commentary
Ecological Assessment
1 Potential for secondary O There are no “Areas of Absolute Exclusion” in the vicinity environmental impacts on that may be affected by the works. “Areas of Absolute Exclusion” 2 Affects an important habitat - - The model predicts a potentially significant increase in suspended solids levels in the vicinity of the coral communities at Shek Kok Tsui, northwest Lamma and at Pak Kok, northeast Lamma. Although not part of the core habitat area, the waters around the site are of marginal importance to the Finless Porpoise. The area is also of limited ecological importance as a fisheries area. 3 Affects a species of - - The coral community at Pak Kok supports species of conservation importance conservation importance that the model predicts may be adversely affected during the construction of the island landfill. There is some potential for disturbance of the Finless Porpoise, either directly through loss of habitat and through marine vessel disturbance, or through the food chain by loss of feeding opportunities in the area during / after site development activities. 4 Potential for Cumulative O There are no anticipated cumulative impacts as the Ecological Impacts on species / Lamma Power Station reclamation works will be habitat of recognised value complete, whilst the proposed WEIF site has not been recommended on environmental grounds. 5 Overall Ecological Impact - / - - The waters near the site are of ecological value due to the presence of the coral community at Pak Kok that the model predicts would be exposed to a significant increase in suspended solids. The waters to the south are also of limited use by the Finless Porpoise, although marine access to the site may lead to increased potential for vessel collision. As such, the overall the impact potential and significance is considered to be ‘Negative – Low / High’. Fisheries Assessment 1 Potential for secondary - The Lo Tik Wan fish culture zone located on the east environmental impacts on “Areas Lamma coast is the nearest “Area of Absolute Exclusion” of Absolute Exclusion” to the site. The model predicts that sediment levels at this zone would become elevated during the works, and thus the potential for adverse fisheries impacts exists. 2 Affects an important mariculture - The Po Lo Tsui fisheries zone is the closest to the site / fisheries resources (including and the most likely to be affected by a decline in water spawning / nursery ground) quality from the works. This zone is also the smallest and most productive (commercially valuable). The other zones are larger and less productive per unit area. Despite this, any impact on the water column from the works would drive the fish from these coastal waters into other protected waters. Thus the potential impact would be marginal. There is also potential for impact upon the Lo Tik Wan fish culture zone as mentioned above. 3 Potential for Cumulative O There are no anticipated cumulative impacts as the Fisheries Impacts on sites of Lamma Power Station reclamation works will be recognised value complete, whilst the proposed WEIF site has not been recommended on environmental grounds. 4 Overall Impact - The model predicts the potential for adverse water quality impact upon the Lok Tik Wan Fish Culture Zone. There would also be direct loss of part of the relatively productive Po Lo Tsui fisheries zone. The overall impact on fisheries is considered to be ‘Negative – Low’.
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Impacts Score Commentary
Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites 2 Potential for archaeological - No marine based deposits of archaeological interest value have been found in the vicinity of the site, although there is evidence of land based archaeological finds nearby on Lamma Island. This suggests that seafaring people have used the coastal area of Lamma Island for several thousands of years. Recognising the lack of archaeological data currently available, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land Heritage Impacts on sites of based (on Lamma Island). Therefore they would not be recognised value affected by this development. 4 Overall Impact - The potential impacts on cultural heritage are considered to be ‘Negative – Low’. Whilst there is not direct evidence of cultural heritage remains in the site area, the occurrence of remains on nearby Lamma Island increases the potential for marine archaeological finds.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no significant Resources impacts on landscape resources. Overall impacts on landscape resources will therefore be Neutral. 3 Impacts on Landscape - - The open, natural character of the West Lamma Character Character Area will be lost with the introduction of the landfill island and the proximity of the island landfill adjacent to the Lamma coast will serve to emphasize its artificial qualities. Impacts on landscape will reduce through the afteruse phase but overall will be Negative – High. 4 Visual Impacts - - Substantial numbers of VSRs in Yung Shue Wan, Hong Kong Island and ferry routes will be substantially impacted upon by the island landfill during both the operation / construction phase and the afteruse phase. Their open and expansive views across to the other outlying islands will be lost. Visual impacts on VSRs in Yung Shue Wan will be especially significant. Overall visual impacts will be Negative – High. 5 Overall Impact - - Overall, landscape and visual impacts will be 'Negative – High’ for the following reasons: • There are no landscape designations covering the disposal site. • As the site is a marine one, no significant landscape resources are affected. • The open, natural landscape character of the outlying islands will be significantly affected by the introduction of the artificial island. • There are large numbers of VSRs surrounding the site (many in very close proximity) that will experience significant visual impacts as a result of the construction/operation and afteruse of the island landfill.
Landfill Gas Assessment
1 Distance between the new / O The nearest sensitive receivers are >250m from the site. extended landfill and SRs 2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. Consultation Zone) 3 Man Made/Natural Pathways for O None. LFG Migration 4 Additional Utilisation of LFG to + There are potential users of LFG at North Lamma (village Reduce GHG Emissions houses and Power Station). 5 Overall Impact O / + ‘Neutral / Positive – Low’
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Table 16.2: Summary of Lamma North Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact - Negative – Low Overall Noise Impact O / - Neutral / Negative – Low Overall Water Quality Impact - Negative – Low Overall Waste Management Impact + Positive Overall Ecological Impact - / - - Negative – Low / High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - - Negative – High Overall Landfill Gas Impact O / + Neutral / Positive – Low
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Table 16.3 Assessment of Significance of Visual Impacts for Lamma North Island Landfill During Construction / Operation (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum Nos. of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Construction / High) before Mitigation (Insubstantial, and Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR 61 Wah Fu, Hong Kong Island 3km Many Intermediate High Moderate to Moderate to Substantial Substantial VR 61a Cyber Port, Hong Kong Island 3km Many Intermediate Medium Moderate Moderate VR 52 Yung Shue Wan, Lamma 1.5km Many Large High Substantial Substantial Island Occupational VSRs VR 54 Lamma Island Power Station 0.8km Few Large Low Moderate Moderate Recreational VSRs VR58 Victoria Peak, Hong Kong 5.5km Few Intermediate Medium Moderate Moderate Island VR55 Cheung Chau 7km Many Intermediate Medium Moderate Slight VR62 Chi Ma Wan, Lantau 10km Few Intermediate Medium Moderate Slight VR63 Penny’s Bay (Future 10km Many Intermediate Medium Moderate Slight Disneyland) VR64 Coastal Headland trail 0.4km Few High Medium Substantial to Substantial to between Yung Shue Wan and Moderate Moderate Tsang Tsai Au, Lamma Island VR11 Area for Boating, Fishing, 0.5 – 10km Many Large High Substantial Substantial Diving and other water sports activities Travelling VSRs VR49 Maritime Vessels 0.5 – 10km Many Large Medium Substantial to Moderate to Moderate Substantial
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Table 16.4 Assessment of Significance of Visual Impacts for Lamma North Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Afteruse High) before Mitigation (Insubstantial, and Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR61 Wah Fu, Hong Kong Island 3km Many Intermediate High Moderate to Moderate Substantial VR 61a Cyber Port, Hong Kong Island 3km Many Intermediate Medium Moderate Slight VR 52 Yung Shue Wan, Lamma 1.5km Many Large High Substantial Substantial Island Occupational VSRs VR 54 Lamma Island Power Station 0.8km Few Large Low Moderate Moderate to Slight Recreational VSRs VR58 Victoria Peak, Hong Kong 5.5km Few Intermediate Medium Moderate Slight Island VR55 Cheung Chau 7km Many Intermediate Medium Moderate Insubstantial VR62 Chi Ma Wan, Lantau 10km Few Intermediate Medium Moderate Insubstantial VR63 Penny’s Bay (Future 10km Many Intermediate Medium Moderate Insubstantial Disneyland) VR64 Coastal Headland Trail 0.4km Few High Medium Substantial to Moderate to Slight between Yung Shue Wan and Moderate Tsang Tsai Au, Lamma Island VR11 Area for Boating, Fishing, 0.5 – 10km Many Large High Substantial Substantial Diving and other water sports activities Travelling VSRs VR49 Maritime Vessels 0.5 – 10km Many Large Medium Substantial Moderate
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17. LAMMA SOUTH ISLAND LANDFILL 17.1 Basic Information Project Title 17.1.1 Lamma South Island Landfill (LSIL) – marine site M.12. Nature of Project 17.1.2 The Project would form a new marine based waste disposal site in waters located off the south of Lamma Island (Figure 17.1). 17.1.3 The LSIL would require the construction of an artificial island of approximately 450ha in size. The site would be designated as a public filling area for the receipt of inert C&D material; once the reclamation is completed, the site would be developed as a landfill for subsequent operation for the disposal of waste. Construction works would be as described in Part A; Section 3.2.
Location and Scale of Project 17.1.4 The LSIL is located approximately 1km to the south of Lamma Island and near the southern fringe of SAR waters. It would cover a site area of some 450ha. Approximately 215Mcum of fill material will be required to construct the artificial island, with a final site formation level to +6mPD. The capacity of the landfill site would be in the order of 65Mcum. 17.1.5 Seabed levels in this area vary from 20 to 22m below Chart Datum. There would be a need to dredge some 10Mcum of muds for the construction of seawalls for the artificial island.
History of Site 17.1.6 The LSIL falls within the Hong Kong Island South & Lamma Island Planning and Development Study, and is on the boundary of the South West New Territories Development Strategy Review area. The site area currently includes designated shipping anchorages at south Lamma. 17.1.7 There are no development recommendations for the site, although there is the possibility that a future breakwater will be developed to the east-northeast. The coastal marine waters around south Lamma have been proposed for protection as a Marine Reserve / Park.
Number and Types of Designated Projects Covered 17.1.8 The LSIL would qualify as a Designated Project under the five categories listed in Part A, Section 2.1.
17.2 Outline Of Planning and Implementation Programme 17.2.1 An outline for the planning and implementation of this site is summarised in Part A; Section 3.3 and an outline programme is shown in Figure 17.2. Assuming landfill operations start in 2020, the LSIL would be full during the period 2030 to 2035, depending upon the rate of waste arisings and the number of other landfills operating concurrently. 17.2.2 The site is currently not covered by any statutory town plans. As described in Section 3.3, Town Planning Ordinance procedures to cover the site would be required and the reclamation would need to be gazetted under the Foreshore & Sea-bed (Reclamations) Ordinance. 17.2.3 This site falls within the boundary of the South West New Territories Development Strategy Review. No recommendations for this area were made under this strategy. 17.2.4 The Recommended Development Strategy formulated under the South West New Territories Development Strategy Review identified the potential of Cheung Chau and Lamma as tourist and recreation developments; this recognised their mountain scenery, appealing coastal areas and the large number of archaeological and historical sites.
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17.2.5 Lamma Island lies to the north of this site and is covered by the Lamma Island OZP Plan no. S/I – LI/3 issued in October 2001. The general planning intentions of the Lamma Island OZP are to conserve the natural landscape, the cultural heritage, the rural character and the car- free environment of Lamma Island; and to enhance the role of Lamma Island as a leisure destination. The Island has been subject to further investigation under the Planning and Development Study on Hong Kong Island South and Lamma Island. 17.2.6 The site is immediately south of a potential Marine Park, recommended under the Strategy Review. 17.3 Possible Impacts on the Environment 17.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the LSIL are outlined below. Figure 17.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 17.1 and 17.2.
Air Quality 17.3.2 The reclamation and landfill development has the potential to cause the following air quality impacts: • Dust (TSP / RSP) and exhaust emissions from on-site plant during construction and operation. • Gaseous emissions during landfill operation and aftercare arising from non-point source emissions and gas flaring / utilisation (including emissions of methane, carbon dioxide, carbon monoxide, sulphur dioxide, nitrous oxides, etc.). • Odours arising during the operation of the landfill from waste decomposition and leachate treatment.
17.3.3 No Air Sensitive Receivers (ASRs) are found within a 500m radius from the boundary of this site. Thus, no significant air quality impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated. 17.3.4 The site lies in an open marine area, with no known developments (existing or planned) within 5km of the site boundary. The build-up of air pollutants is not anticipated. 17.3.5 This is a marine site and marine vessels will be used for waste delivery to the site. The amount of air pollutants resulting from the territory-wide waste delivery (per kg waste handled) to the site is anticipated to be lower, compared to a land based site that relies solely on road transport. The estimated cumulative distance to be travelled from the existing and planned (South East Kowloon RTS to be commissioned in 2012) marine RTSs to the site is approximately 290km. Given the likely distance to be travelled and the benefit of the use of marine transport, the regional impacts from waste transportation are considered to be neutral.
Noise 17.3.6 The reclamation and landfill development has the potential to cause the following noise impacts:
• Construction – from dredging, tipping, piling works and general construction activities; • Operation – from the use of fixed plant, marine vessels, waste reception area, pumping plant, possible helicopter noise etc. 17.3.7 No noise sensitive receivers are found within a 300m radius from the boundary of this site. Thus, no significant noise impacts associated with reclamation, operation and construction of the landfill facility within the site are anticipated.
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17.3.8 Although not anticipated at this stage, it is possible that activities could continue beyond normal working hours during the construction and operation phases. This would depend upon working arrangements for fill delivery, day-to-day landfill operations and the overall construction programme. However, as this is an offshore site with no NSRs in the vicinity, the more stringent requirements for noise emissions during the evening and night-time periods are not expected to be an issue for this site. 17.3.9 Potential operational phase noise impacts would need to be considered in subsequent studies in the event that the island reclamation is used for other land uses (in addition to landfill) or a separate afteruse is developed on top of the landfill following completion of the landfilling operations. 17.3.10 The site can only be accessed by marine traffic during both operation and construction phase. Noise from land based waste delivery vehicles is not a concern for this site.
Water Quality Baseline Conditions at the Site 17.3.11 The site would fall wholly within the Southern Water Control Zone (WCZ). Broadly representative water quality data for the area is available from two of EPD’s routine marine water quality monitoring stations: SM18 some 5km to the west and SM19 5km to the east. There is no sediment quality monitoring station at these locations, although there is one such station (ref. SS3) also around 5km distant to the northwest of the site (near the potential new Lamma Breakwater waste disposal site (Site M6). 17.3.12 As with the North Lamma site, the marine waters around the South Lamma site are also influenced by discharges from the Pearl River, albeit to a lesser extent. The mean TIN concentration for the year 2000 at station SM7 (north Lamma) was 0.24mg/L compared with levels at SM18 and SM19 (south Lamma) of 0.13mg/L. There were similar trends at these locations for nitrate-nitrogen and TKN. As with north Lamma waters, the WQO for TIN at stations SM18 and SM19 was exceeded (non-compliance), whilst those for dissolved oxygen and un-ionised ammonia were fully complied with (EPD, 2001). 17.3.13 It is also of note that levels of BOD, E.coli and faecal coliforms were relatively low at the southern locations compared with station SM7. This could be due to factors such as sewage discharges into the West Lamma channel and greater flushing capacity (increasing oceanic influence) in the waters around south Lamma. Generalised data shows that the ebb tide current through the area is the strongest, and particularly during the wet season. The flood tide current is relatively weak – especially in the wet season due to southward flow from the Pearl River. 17.3.14 EPD data at station SS3 shows marine sediment quality to be good at this location, with all tested parameters within the Lower Chemical Exceedance Level. The sediment quality around the site is considered to be of similarly good quality. Key Issues and Sensitive Receivers 17.3.15 The project has the potential to cause the following water quality impacts:
• Sediment loss to the water column during dredging / reclamation; • Runoff with elevated levels of suspended solids from the site during landfill construction (post-reclamation); and • Change in the hydrodynamic regime (i.e., change in flushing capacity and sediment deposition / erosion patterns). 17.3.16 Identified Water Sensitive Receivers (WSRs) present in the vicinity of the site are:
• Cooling water intake for HEC Lamma Power Station; • Gazetted beach near the Power Station at Hung Shing Ye; • Gazetted beach at Lo So Shing; and
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• Secondary contact recreation sub-zone around the west and south Lamma coastline.
17.3.17 In addition, there are a range of aquatic and inter-tidal ecological receivers within the vicinity of the site that may be sensitive to any decline or change in the water quality or sediment deposition / erosion patterns. Impacts upon these are discussed under the “Ecology” and “Fisheries” subsections. The sensitive receivers include:
• Green Turtle nesting habitat at Sham Wan beach; • Core habitat area for the Black Finless Porpoise at Ha Mei Tsui; and • General Marine and coastal waters around the proposed South Lamma Marine Park / Reserve.
17.3.18 The locations and uses of these sensitive receivers are shown in Figure 17.1. Reclamation and Site Formation 17.3.19 Reclamation and site formation activities, if not carefully controlled, may potentially lead to adverse water quality impacts from increased suspended solids levels in the water column and reduced dissolved oxygen levels. Sediment may be carried by the prevailing flood tide current towards WSRs at Ha Mei Wan to the north. However, water circulation in this bay area is negligible and it is considered that sediment would not reach either of the gazetted beaches. Given the stronger water current at the mouth of the bay, it is considered that there is more potential for any sediment plume that may form to be transported towards the water intake for the Lamma Power Station. The placement of fill for island construction is likely to lead to localised increases in suspended solid levels. The hydrodynamic and water quality modelling indicated that there would be no WQO exceedance in Phase 1 construction. Increases are however predicted at MP6 (21.22%), FP1 (19.58%), NS4 (22.61%) and NS5 (23.04%) in the dry season and at NS5 (16.86%) in the wet season. No WQO exceedence is predicted in Phase 2 construction, however, increased levels of SS are predicted at MP6 (17.26%), FP1 (15.61%), NS4 (18.84%) in the dry season and at NS5 in both the dry (17.72%) and wet (22.48%) seasons. In Phase 3 construction, WQO exceedence is predicted at MP6 (38.10%), FP1 (33.78%), NS4 (38.19%) and NS5 (44.30%). An increased level of SS is also predicted at NS5 (17.25%) in the wet season. Hydrodynamic and Water Quality Impacts Following Island Formation 17.3.20 It is predicted that the presence of the island would cause a significant increase (45.50%) in the accumulated flow through the East Lamma Channel, and a decrease (26.56%) through the West Lamma Channel during the dry season. In the wet season a significant flow (23.48%) is predicted for the Tathong Channel and reductions (approximately 9%) would occur at East and West Lamma Channels. The two velocities were predicted to increase significantly in the area between the island and Lamma Island during the neap flood tide of the wet season. The overall current magnitude is predicted to reduce by 2.5% and 12.32%, on average, to the northeast and north west of the site respectively. 17.3.21 In the hydrodynamic and water quality modelling, 22 sensitive receivers that are close to the site were selected for presentation. Of 22 indicator points, 17 chosen indicator points (MP6, FP1, GT1, CW4, FC4, FC3, GB5, SC2, FP5, GT2, SC3, FP6, NS4-6, NS8-9) are located in the Southern WCZ. The remaining 5 indicator points are located in Mainland waters (MF8-9, MF13-15) and classified as Category 2 in the Mainland Sea Water Standard. 17.3.22 According to the dry season water quality modelling results, the predicted 90%ile DO for depth average and bottom layer ranged from 6.20 to 7.03mg/L and are above the WQO of 4mg/L and 2mg/L respectively as well as the Mainland standard of 5mg/L. The largest reduction in 90%ile depth averaged DO was found at FC4 (Fish Culture Zone at Sok Kwu Wan) with difference of 3.96%. For the 90%ile bottom DO, where there were decreases in the predicted values, the reduction were all below 1%, except for FC4 (Fish Culture Zone at Sok Kwu Wan) where the difference was 4.11%.
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17.3.23 The predicted average dry season salinity ranged from 33.89 to 34.00ppt. The differences in salinity levels caused by the presence of the island were minimal (less than 1%) at all the selected indicator points as compared to the WQO requirements that change due to any waste discharge should not exceed 10% of natural ambient level. 17.3.24 The predicted dry season SS levels indicator points were in the range of 3.65 to 4.37mg/L. Comparing to the baseline water quality results, the percentage differences in SS level are considered small at all indicator points (within 8%) and are well below the WQO of 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L. 17.3.25 The predicted E.coli levels in the dry season ranged from 1 to 18count/100ml. The increase in average E.coli levels caused by the presence of the island were significant at NS9, GB5 and FC4 but the predicted E.coli levels at these 3 indicator points (11, 15 and 18count/100ml respectively) were still well within the WQO of 610cfu/100mL and the Mainland standard of 200count/100ml. The predicted average E.coli levels are 1count/100mL for most of the indicator points. 17.3.26 The predicted average dry season UIA (0.00253 – 0.00358mg/L) at all indicator points were very small as compared to the WQO of 0.021mg/L and the Mainland standard of 0.020mg/L. 17.3.27 The predicted dry season TIN levels (0.0750 – 0.0912mg/L) at the indicator points in Mainland were well below the Mainland standard of 0.3mg/L. Since the Hong Kong WQO of TIN is an annual mean value, the predicted mean TIN levels at the indicator points in Hong Kong waters for the dry and wet seasons were averaged to represent the annual mean values. All of the 17 indicator points in Hong Kong waters have breached the WQO of 0.1mg/L with calculated annual mean values ranged from 0.1390 to 0.1941mg/L. However, the calculated averaged baseline concentrations at these stations have also exceeded the WQO. 17.3.28 According to the water quality modelling results for the wet season, the predicted average 90%ile DO for depth averaged and bottom layers ranged from 4.97 to 6.29mg/L and the values are above the WQOs of 4mg/L and 2mg/L respectively as well as the Mainland standard of 5mg/L. Comparing to the baseline water quality results, the percentage differences for 90%ile depth-averaged DO were minimal with differences of less than 1.5% at all indicator points. The percentage differences in 90%ile bottom DO were also small with values from 0.19 to 3.93%. 17.3.29 The predicted average salinity in the wet season ranged from 20.19 to 30.50ppt. Compared to the baseline water quality results, the percentage differences in salinity caused by the presence of the island were minimal (less than 2%) at all of the selected indicator points. The differences were well below the WQO requirement that change due to any waste discharge should not raise the natural ambient level by 10%. 17.3.30 The predicted SS levels in the wet season at the indicator points were in the range of 3.06 to 5.58mg/L. The differences were less than 3% which are small as compared to the WQO requirement that any waste discharge should not raise the natural ambient level by 30% as well as the Mainland standard that man-made increment should not exceed 100mg/L. 17.3.31 The predicted wet season E.coli levels indicator points were low and ranged from 1 to 16count/100mL which are well below the WQO of 610cfu/100ml. The increase in average E.coli levels caused by the presence of the island were significant at GB5, FC4 and NS9 but the actual values at these 3 indicator points were very small (8, 9 and 12count/100ml respectively) and were well within the WQO of 610cfu/100mL as well as the Mainland standard of 200count/100mL. 17.3.32 The predicted average wet season UIA (0.00250 – 0.00522mg/L) at all indicator points were low and well below the WQOs of 0.021mg/L for annual mean and the Mainland standard of 0.020mg/L. It is predicted that the island would increase the UIA levels at most of the indicator points with the largest increase at NS5 (Fishery Nursery/Spawning Ground South of Lamma Island) with value of 4.76%.
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17.3.33 The predicted wet season TIN levels (0.1095 – 0.2798mg/L) at the indicator points in Mainland were below the Mainland standard of 0.3mg/L. Meanwhile, the predicted TIN levels (0.186 – 0.291mg/L) were relatively higher as compared to the dry season data. All stations in Hong Kong waters were breached the WQO of 0.1mg/L as discussed in Section 17.3.27 above. Cumulative Impacts 17.3.34 Two other projects in the vicinity of the site with potential for a cumulative effect on hydrodynamics / water quality are the ongoing extension of the Lamma Power Station and the potential establishment of a Waste-to-Energy Incineration Facility (WEIF) adjoining the Power Station extension. 17.3.35 The Power Station extension is due to be fully completed by the year 2012. It was concluded in the EIA Study for the Lamma Power station extension that development of the extension in isolation and in tandem with the potential WEIF would not lead to any adverse hydrodynamic / water quality impacts. Ultimately the siting of a WEIF at Lamma was not recommended on environmental grounds.1 Although there are ongoing studies for the development of a “waste to energy facility” for the HKSAR, for the purpose of this assessment it is assumed that any future facility would not be located at Lamma Island. As such, this precludes the potential for cumulative hydrodynamic / water quality impacts.
Waste Management / Disposal Impacts 17.3.36 For construction of the “island” on which the landfill would be located, inert C&D material would be brought in exclusively by marine vessel, from a network of barging points in the SAR. The location of barging points would vary during the filling process, according to the source of materials at any given time. 17.3.37 Whilst various options for construction that avoid dredging have been investigated, it is anticipated that muds would need to be excavated to facilitate construction of the outer seawall, prior to public filling. Excavated muds would then be disposed of within the area to be reclaimed with public fill. Following this, the “island” would act as a major recipient of municipal solid waste and other landfilled waste streams. 17.3.38 Anticipated volumes of materials are as follows:
• Volume of public fill that could be accepted for island construction: 215Mcum • Volume of muds be dredged for outer seawall: 10Mcum
17.3.39 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. These would be managed as described in Section 5.5. 17.3.40 Only marine vessels will be used to deliver waste to the site. As such, the GHG emission rate (per kg waste handled) is expected to be low compared to using road transport. Based on the information contained in the Preliminary Marine Review (March 2002), the cumulative distance to be travelled is around 290km. In view of this, the impacts associated with GHG emissions are considered to be insignificant (neutral).
Ecology Baseline Conditions 17.3.41 There are a number of ecological resources of conservation interest and significance in the vicinity of the site.
1 CDM (1998). Feasibility Study of Waste-to-Energy Incineration Facilities: Site Assessment Report – Lamma Island. Submitted to EPD, July 1998.
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17.3.42 The Green Turtle Chelonia mydas is the only turtle species known to breed locally, with nesting only reported thus far at the sandy beach at Sham Wan, south Lamma.2 The Green Turtle is protected under the Wild Animals Protection Ordinance, Cap.170 and is listed under Appendix I of CITES. The beach at Sham Wan and the nearby shallow waters were designated a SSSI in June 1999, whilst (since 1999) approximately 0.5ha of the nesting area including the beach is a “Restricted Area” between June and November. 17.3.43 The Black Finless Porpoise frequents the waters around the site and generally around south Lamma throughout the year. Seasonal distribution data collated by the AFCD shows that the waters around Mei Ha Tsui are a very important part of the species’ core habitat between September and May.3 The Chinese White Dolphin prefers waters further to the west, although there have been occasional sightings in the West Lamma Channel around 5km from the site.4 17.3.44 Inter-tidal resources at southwest Lamma were investigated under the HEC Power Station Extension study. The macroinvertebrate and macroalgae community around Ha Mei Tsui was relatively diverse amongst the six west coast survey locations. The most abundant species were the Chiton Acanthopleura japonica, the Limpet Patelloida saccharina, and the macroalgae Neogoniolithon misakiense. None of the intertidal community species are of particular conservation significance. 17.3.45 The Power Station Extension study described the shallow sub-tidal waters at southwest Lamma, as being characterised by steep rocky substrate comprised of boulders. This substrate character (combined with the peninsula status of the location and the water current) appears to be conducive to coral establishment as the greatest coral diversity on the west Lamma coast is to be found in this area. Hard coral of the genus Tubastrea was reported as abundant on the southwest-facing coast, whilst three species of soft coral, three of sea whip, one sea pen and one sea fan were also observed in the 1998 survey. Other abundant coral reef associates reported in large numbers were the sea cucumber Colochirus crassus and the long-spined sea urchin Diadema setosum (ERM, 1999). It was concluded that the coastal sub-tidal habitat around Ha Mei Wan, southwest Lamma, is of “high ecological value”. 17.3.46 Nearby, at the mouth of Sham Wan, a separate dive survey identified hard coral of the genus Acropora at depths of up to 5mPD, concluding that the conservation value of this location was high.5 17.3.47 The sub-tidal benthic community at the site is not likely to be as diverse as the shallow coastal waters. The greater offshore water depth (around 20m) will limit the community type, whilst the substrate will not be characterised by boulders as at Ha Mei Tsui. The seabed is likely to be more homogenous, comprised of relatively uniform silty sand as at EPD’s sediment monitoring station SS3 (“Water Quality” subsection refers). It is anticipated that polychaetes, molluscs and crustaceans will be the most abundant groups in the benthic community at the site (see also “Fisheries” subsection). 17.3.48 Fisheries resources of ecological significance in the area are present south of Cheung Chau and south of Lamma Island. These areas are important spawning and nursery grounds for a range of fish and crustacean species.6 These waters also support the squid Loligo sp., the lion-head fish Collichthys lucida and the tiger-tooth croaker Otolithes argenteus that comprise the most common and numerically important prey species of the Finless Porpoise.7
2 AFCD (2001). AFCD Website. Conservation: Protection of Green Turtles. [www.afcd.gov.hk/con_new/turtle.htm].
3 AFCD (2001). AFCD Website. Conservation: Finless Porpoise. [www.afcd.gov.hk/con_new/finpor.htm].
4 AFCD (2001). AFCD Website. Conservation: Chinese White Dolphin. [www.afcd.gov.hk/con_new/cdp_distri4.htm].
5 Binnie (1995). Marine Ecology of Hong Kong. Report on Dive Surveys – Volume I. Fill Management Study –Phase IV. Submitted to CED, HKSAR Govt.
6 ERM (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to AFCD, HKSAR Govt.
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Direct Habitat Loss 17.3.49 The site footprint covers a surface area of 450ha and the site is entirely sub-tidal. It is anticipated that there will be no benthic species of particular ecological significance in the area. 17.3.50 As regards open waters, distribution data for the Black Finless Porpoise collated by AFCD shows that the marine waters in this area are part of the core habitat for this species. The Finless Porpoise can be found in the area of the site throughout the year. 17.3.51 The marine waters in this area are also important for the Green Turtle. Given the location of the site relative to the turtle’s nesting ground at Sham Wan, there is a high chance that the site would be directly in the line of the female turtle’s approach to Sham Wan as it migrates back for egg laying. The waters may also be important to the Green Turtle as a breeding ground. Water Quality / Hydrodynamics 17.3.52 Given the sensitivity of the area for Green Turtle breeding, any change in water quality could have adverse impacts upon the use of the area by this species. Likewise, a change in beach morphology from sediment deposition from dredging / reclamation activities, or any other disturbance, may be sufficient to disturb the Green Turtle. Similarly, the Finless Porpoise, for which the area forms part of the core habitat, could be driven out by dredging and reclamation activities. Any deterioration in water quality would drive fish from the area due to their sensitivity to increased suspended sediment levels, resulting in reduced feeding opportunities for the Green Turtle and Finless Porpoise in these waters. 17.3.53 The model predicts that increases in suspended solids would be negligible in the area (< 2.0mg/L), including off the Ha Mei Tsui peninsula that forms part of the core area for Finless Porpoise sightings (FP1). Negligible increases in sediment levels are also predicted during the construction phase near to the Sham Wan SSSI (close to NS5 – “Fisheries” sub- section refers) and the southern edge of the potential South Lamma Marine Reserve / Park (MP6). The predicted worst-case scenario increase, under Phase 3 construction dry season, is no greater than 1.5mg/L and would not affect the ecological receivers in the area. Marine Vessel Disturbance 17.3.54 The Sham Wan “Restricted Area” was established in order to protect the nesting Green Turtle from any form of disturbance during their nesting season. It is noted that any development and human activities that change the natural environment of the nesting site and/or cause obstructions to their migratory route may deter nesting and return of turtles. 17.3.55 Particular threats to the turtle include illumination (possibly from the new waste facility) that may deter the female from egg laying and / or if eggs are laid the hatchlings may be disorientated when approaching the sea (hatchling orientation towards the sea is guided by moonlight). There is also potential for construction and operational debris from the site to wash ashore at Sham Wan, thus impinging the movement of nesting females and hatchlings. Vessel movement in the area may also affect the turtles through increased potential for vessel collision and vessel engine noise / vibration. 17.3.56 From a study conducted on behalf of the AFCD, it is known from data on strandings of Black Finless Porpoise specimens that vessel collision is a significant cause of death (Jefferson, 2001). As the south Lamma area is part of the core habitat for Finless Porpoise any increase in marine traffic required for site formation / reclamation activities and facility operation could lead to an increase in incidences of vessel collision.
7 Jefferson, T.A. (2001). Conservation Biology of the Finless Porpoise in Hong Kong Waters. Submitted to AFCD, HKSAR Government.
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17.3.57 The Finless Porpoise may also be prone to adverse impact from general disturbance associated with facility development and operation, including vessel noise / vibration.
Fisheries 17.3.58 There are two fishing zones in the vicinity of the site: Ha Mei (zone 0098) and Tai Kok (zone 0099). Available data indicates that both of these zones are similarly popular in terms of the number of fishing vessels utilising the zone compared with other fishing zones to the north (“North Lamma” report refers). Likewise, the productivity of these two zones is similar on a unit area basis. In terms of value ranking for adult fish, Tai Kok ranks 50 / 210 zones compared with 66 / 210 for Ha Mei. Ha Mei has slightly better ranking for fry fish 45 / 89 compared with 49 / 89 for Tai Kok. The overall value of both Tai Kok and Ha Mei were high for the HKSAR, ranking 84th and 70th respectively out of 210 fishing zones (ERM, 1999). 17.3.59 The most commonly caught species in these two zones were the same, including the scad Caranx spp., the sardine Sardinella jussieui, and the croaker Argyrosomus spp. The catch of Mantis shrimp Oratosquilla spp. – a commercially valuable species – was the 5th most important in terms of species weight in both zones (ibid.). Other commercially important species for which the south Lamma area is a known spawning ground include the coastal mud shrimp Solenocera crassicornis, and the Jinga shrimp Metapenaeus affinis. The marine waters are also an important nursery area for the shrimp Metapenaeopsis barbata and M.palmensis, and croaker and grouper fry, amongst others (ERM, 1998). Due to their importance as a nursery area for commercial fish species it has been proposed that the waters around south Lamma be designated as a Fisheries Protection Area (ibid.). 17.3.60 Construction of the LSIL has potential to create adverse impacts on fisheries resources in the area. Marine dredging works may affect fisheries in the area; particularly on the ebb tide when the current from the West Lamma Channel may transport sediment south from the works area into productive fisheries grounds. General reclamation and site formation activities may also lead to adverse impacts from sediment dispersal away from the works location. Despite these potential impacts, the model predicted only a slight and insignificant increase in suspended solids levels in open water nursery / spawning area (NS4 & NS5) close to the site. These worst-case scenario predicted increases above the baseline were during Phase 3 construction dry season and amount to 1.52mg/L at NS4 and 1.75mg/L at NS5. Under the worst-case scenario (i.e., NS5) a total sediment concentration of 5.70mg/L is predicted - significantly lower than the generally accepted threshold for “adult fish” of 50mg/L. Even taking a precautionary approach whereby the permissible sediment concentration at spawning / nursery areas is far lower that for adult fish (say, 50% lower, or 25mg/L), no adverse impacts would arise.
Cultural Heritage 17.3.61 There is no immediate evidence of archaeological remains in this area. However there are a significant number of archaeological sites on Lamma. The presence of sites on land strongly suggests that seafarers would have used the natural harbours of the islands and the waters around the site for several thousand years. 17.3.62 Recognising the likelihood of archaeological remains in this area and the lack of archaeological data currently available for this site, a detailed marine archaeological investigation should be carried out in any future studies.
Landscape and Visual 17.3.63 Landscape Planning Designations - this area of landscape is not covered by any planning designations reflecting landscape/landscape values and so there will be no impact on these values. 17.3.64 Landscape Resources - the site lies in a marine area, so that the only landscape resource affected will be an area of offshore water. Given the low sensitivity of this resource, there will be no significant impacts on landscape resources.
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17.3.65 Landscape Character- the site is located in the Southern Coastal Waters LCA, immediately to the south of Lamma Island (Figure 17.4). The landscape of this part of Hong Kong is open and in exposed offshore waters with little sense of containment other than distant islands in PRC waters and the distant islands of Lantau, Lamma and Cheung Chau. The area is given some landscape context by the proximity of Lamma Island. Shipping introduces movement and certain artificial elements into what is otherwise a predominantly natural setting (Figure 17.3). 17.3.66 There exists potential for substantial impacts on landscape character resulting from construction / operation works, which will introduce new elements which are incompatible with the existing natural landscape. During the afteruse phase of the landfill, these impacts are likely to be reduced, as the completed island is restored. The character of the island is however generally inconsistent with the open, natural character of the other landscape, and the island's proximity to Lamma will further emphasise its artificial characteristics. As a consequence of this, the long-term impact on landscape character will remain as moderate to substantial. 17.3.67 VSRs - VSRs affected by the proposals are identified in Tables 17.3 and 17.4. The extent of the project visual envelopes is shown in Figure 17.5. 17.3.68 Because of the location of the island there are no areas of large population close to the site. Key residential VSRs in the area are found at Stanley and Nam Tam. They are however approximately 7km and 10km from the site respectively (Figure 17.6). Recreational VSRs will be affected, such as visitors to Shan Tei Long, Chung Hom Kok Park, Fa Peng Beach and those engaged in marine or other water sport activities. Other VSRs, such as travellers on vessels using the fairways and shipping lanes, although transient, will also be affected. 17.3.69 These VSRs will experience works on the landfill (shipping, marine vessels and partially constructed island) as artificial elements contrasting with the coherent qualities of the existing landscape, and resulting visual impacts will be substantial to moderate for close VSRs. The impact of the island is greatly reduced by the viewing distance of the majority of VSRs. After the restoration of the landfill, the visual impact of the island will be reduced to slight to insubstantial for most VSRs given the remote location of the island. The exception to this is the VSR group at Shan Tei Long where the visual impact will remain moderate to substantial.
Landfill Gas 17.3.70 There are no sensitive receivers (targets) or pathways within 500m of the site and therefore no potential off-site landfill gas hazard. Landfill gas would have safety implications for those working on the site. In the event that the reclamation on which the landfill would be constructed is also developed for other afteruses, the potential operational phase landfill gas hazards would need to be considered for those developments. 17.3.71 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source in surrounding communities, is not considered practical. However, it will be used as an on-site energy source.
17.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 17.4.1 Environmental design measures have been identified in Part A (Section 3.8) and generic approaches to mitigating impacts on different environmental parameters are outlined in Part A (Section 5). Whilst the specific requirement for environmental mitigation would be dependent upon the findings of an EIA, the following environmental protection measures are site-specific to Lamma South artificial island site.
Air Quality 17.4.2 No specific air quality mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
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Noise 17.4.3 No specific noise mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Water Quality 17.4.4 Mitigation is likely to be required to prevent impacts during dredging and filling for the reclamation. Construction procedures, defining the rates and method of dredging and filling taking in to account the hydrodynamics of the surrounding waters and tidal effects (ebb and flood) should be defined in the EIA. If significant impacts are predicted, a silt curtain may be installed around the immediate works area to prevent dispersion of sediments.
Waste Management 17.4.5 No specific waste management mitigation measures are recommended at this stage, other than good site practice as described in Part A (Section 5).
Ecology 17.4.6 It is proposed that marine vessel movements to and from the LSIL should avoid the waters around southwest Lamma due to the importance of the area as a habitat for the Finless Porpoise. In particular, vessel movement from the north should ideally approach the site via the East Lamma Channel.
Fisheries 17.4.7 There are no particular measures that are proposed for fisheries resource protection. Cultural Heritage 17.4.8 There are no particular measures that are proposed for protection of cultural heritage resources.
Landscape & Visual 17.4.9 Mitigation Measures - Landscape and visual mitigation measures are outlined in Section A of the Report and are illustrated in Figure 17.8.
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17.5 Summary 17.5.1 A summary of the SEA for the LSIL is provided in Tables 17.1 and 17.2:
Table 17.1: Evaluation Summary for Lamma South Island Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no air sensitive receivers (ASRs) within 500m land use of the site. 2 Presence of topographic O The site does not lie within any airshed and generally features which could decrease experiences wind. It is unlikely that dust or odours would or exacerbate impacts accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative Impacts of relevant O The site is located in open marine waters to the southern emissions (TSP (construction), HKSAR waters fringe, with no known developments that NOx, CO, SO2 – LFG Flare) have relevant emissions within 5km from the site. taking into account ambient conditions 5 Total Emissions of Air Pollutants O Waste will be delivered to the site by marine vessel and from the territory-wide waste the cumulative distance to be travelled is estimated to be transportation between the RTSs 290km. and the site 6 Overall Impact O ‘Neutral’.
Noise Assessment
1 Distance to areas of noise O There are no noise sensitive receivers (NSRs) within sensitive land use 300m of the site. 2 Topographic Features O The site is located within open marine waters with no NSRs located within 300m from the site boundary. (Only applicable if there are Therefore, this criterion is not applicable. NSRs within 300m) 3 Cumulative Impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. 4 Overall Impact O ‘Neutral’.
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Impacts Score Commentary
Water Quality Assessment 1 Water Course Diversion O Artificial island. Not relevant. 2 Potential for sediment O None. EPD routine sediment quality monitoring data contaminant release collected near the site shows that the marine sediment is not contaminated. 3 Potential impacts on WSRs - - Dredging and reclamation activities during construction (including increase or would cause WQO exceedances in the dry season. exceedance of WQO) It is predicted that TIN standard in the operational phase would breached, however, it was also breached in the baseline scenario and the elevation due to the presence of island was not significant, therefore, the island would not be the cause of the exceedance. 4 Potential Impacts on O Artificial island. Not relevant. Groundwater 5 Potential Cumulative Impacts O Given that the reclamation works for the ongoing Lamma Power Station extension will be complete some time before 2010, and the conclusion that the Lamma WEIF is too environmentally sensitive, no cumulative impacts are anticipated. 6 Overall Impact - There is some potential for adverse water quality impact on WSRs in south Ha Mei Wan and more potential for impact upon the secondary contact recreation sub-zone at south Lamma. However, the impact potential is moderate and impacts are not anticipated for the other evaluation criteria, so overall: ‘Negative – Low’. Waste Management Assessment 1 Balance of Materials + The site could accommodate major volume of public fill (surplus/deficit of public fill (215Mcum) negating the need to import filling material for needed for landfill development) site formation. Dredged muds will be incorporated with the fill materials within the island footprint. 2 GHG emissions from mode of O Waste will be delivered to the site via marine vessel. The transport for delivery of waste to distance travelled from marine RTS(s) to the site has the site from RTSs been estimated to be 290km. 3 Overall Waste Impact + ‘Positive’.
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Impacts Score Commentary
Ecological Assessment 1 Potential for secondary - - The Sham Wan SSSI and “Restricted Area” is located environmental impacts on “Areas 1km north of the site. There is potential that sediment of Absolute Exclusion” would be transported north towards the coastal areas during reclamation and dredging works. The area has also been proposed as a Marine Park. 2 Affects an important habitat - - The waters in the area are part of the core habitat for the Finless Porpoise and are used as a breeding / feeding area by the Green Turtle. The area of usage by these species includes the footprint of the site. There are also coral communities of high conservation value located at Ha Mei Tsui (southwest Lamma) and at the tip of Sham Wan (south Lamma). 3 Affects a species of conservation - - Both the Finless Porpoise and the Green Turtle are listed importance under Appendix I of CITES and are protected under the Wild Animals Protection Ordinance (Cap. 170). These species would be susceptible to impact from habitat loss and injury / disturbance related to vessel movement. 4 Potential for Cumulative O There are no concurrent works in the vicinity of the site Ecological Impacts on species / that have potential to create cumulative ecological habitat of recognised value impacts. 5 Overall Ecological Impact - - The site would be immediately adjacent to the proposed Lamma South Marine Park, and is approximately 1km south of the Green Turtle Restricted Area at Sham Wan. The area is the most important in the HKSAR for the Green Turtle and is near to a core habitat for the Finless Porpoise. There are also coral communities of high conservation value on the south-facing Lamma coastline. Given this conservation value, the site is considered as having ‘Negative – High’ impact potential. Fisheries Assessment 1 Potential for secondary O There are no existing “Areas of Absolute Exclusion” that environmental impacts on “Areas would be affected by the works. of Absolute Exclusion” 2 Affects an important mariculture - / - - The waters around the site are an important spawning / fisheries resources (including and nursery ground for a range of commercially spawning / nursery ground) important fish and crustaceans. The same area has been proposed for protection as fisheries spawning ground. The two fishing zones in the vicinity of the artificial island are ranked highly in terms of fisheries productivity in the HKSAR. These areas may be put under some stress from the predicted increase in sediment levels during construction works. 3 Potential for Cumulative O There are no anticipated cumulative impacts. Fisheries Impacts on sites of recognised value 4 Overall Impact - The waters off south Lamma around the site are of fisheries importance as a spawning and nursery ground for species of commercial value. However, there are no impacts on protected areas or cumulative effects, so overall: ‘Negative – Low’.
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Impacts Score Commentary
Cultural Heritage Assessment
1 Important cultural (Declared, O There are no known sites of cultural heritage Deemed or Graded sites) / significance. archaeological sites 2 Potential for archaeological - No marine based deposits of archaeological interest value have been found in the vicinity of the site, although there is evidence of land based archaeological finds nearby on Lamma Island. This suggests that sea-faring people have used the coastal area of Lamma Island for several thousands of years. Recognising the lack of archaeological data currently available, it is considered that the likelihood of archaeological remains in this area is reasonable. A detailed marine archaeological investigation should be carried out in any future studies. 3 Potential for Cumulative O The nearest sites of cultural heritage value are land Heritage Impacts on sites of based, (on Lamma Island). Therefore they would not be recognised value affected by this development. 4 Overall Impact - The potential impacts on cultural heritage are considered to be ‘Negative – low’. Whilst there is not direct evidence of cultural heritage remains around the site, the occurrence of remains on nearby Lamma Island increases the potential for marine archaeological finds.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for Landscape O This area of seascape is not covered by any planning Planning and Designations designations reflecting landscape/seascape values and so there will be no impact on these values. Overall impacts will therefore be Neutral. 2 Impacts on Landscape O As the site lies in a marine area, there will be no significant Resources impacts on landscape resources. Overall impacts will therefore be Neutral. 3 Impacts on Landscape - - The open, natural character of the south coast of Lamma Character Island will be lost as well as the isolated character of the Southern Coastal Waters Landscape Character Area. The impact on this character area will be exacerbated by the proximity of the island to Lamma Island which will have the effect of emphasizing the artificial characteristics of the landfill island. Resulting overall impacts on landscape character will be Negative – High. 4 Visual Impacts - / - - The location of the island is a considerable distance from most populated areas and as a result will have a slight to moderate impact on their visual amenity. Recreational receivers will be most impacted by the site receiving substantial to moderate impacts. During the afteruse phase, the impacts will reduce to slight to insubstantial for most VSRs, given their relative viewing distances. Again the exception is the recreational VSRs in close proximity to the site. Resulting overall visual impacts will be Negative – Low / High. 5 Overall Impact - / - - Overall, landscape and visual impacts will be ‘Negative – Low / High’ for the following reasons: • Being a marine site, no significant landscape resources are affected. • There are no significant landscape designations covering the disposal site. • The open, natural and isolated landscape character of the coastline to the south of Lamma will be significantly compromised. • There are low numbers of residential visual receivers close to the island, and the impact on these receivers will not generally be very high.
Landfill Gas Assessment 1 Distance between the new / O The nearest sensitive receivers are >250m from the extended landfill and SRs project site. 2 Number of Receivers within O There are no sensitive receivers within 250m of the site. 250m (i.e. the LFG Consultation Zone) 3 Man Made/Natural Pathways for O None. LFG Migration 4 Additional Utilisation of LFG to O There are no potential users of LFG (other than on-site Reduce Greenhouse Gas use) Emissions 5 Overall Landfill Gas Impact O ‘Neutral’.
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Table 17.2: Summary for Lamma South Island Landfill SEA
Overall Impacts Score Commentary
Overall Air Quality Impact O Neutral Overall Noise Impact O Neutral Overall Water Quality Impact - Negative – Low Overall Waste Management Impact + Positive Overall Ecological Impact - - Negative – High Overall Fisheries Impact - Negative – Low Overall Cultural Heritage Impact - Negative – Low Overall Landscape & Visual Impact - / - - Negative – Low / High Overall Landfill Gas Impact O Neutral
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Table 17.3 Assessment of Significance of Visual Impacts for Lamma South Island Landfill Phase During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum Nos. of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Construction / High) before Mitigation (Insubstantial, and Source(s) Operation Measures Slight, Moderate, (Negligible, Small, (Insubstantial, Substantial) Intermediate, Slight, Moderate, Large) Substantial) Residential VSRs VR 65 Stanley 7km High Intermediate High Moderate to Slight Substantial Recreational VSRs
VR 66 Shan Tei Long (Mt. 2km Few Large High Substantial Substantial Stenhouse), Lamma Island VR 67 Chung Hom Kok Park 7km Few Intermediate High Moderate to Moderate to Slight Substantial VR 55 Cheung Chau 10km Few Small High Moderate Slight to Insubstantial VR 11 Area for Boating, Fishing, 0.5km - 10km Few Large High Substantial to Substantial to Diving and other water sports (varies) Moderate Moderate activities Travelling VSRs VR 49 Maritime Vessels 0.5km - 10km Few Intermediate Low Slight to Moderate Slight (varies)
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Table 17.4 Assessment of Significance of Visual Impacts for Lamma South Island Landfill During Afteruse Phase (Note: All impacts adverse unless otherwise noted)
Identity Key Visually Sensitive Approx Minimum No.s of VSRs Magnitude of VSR Sensitivity Impact Significance of No. of Receiver (VSR) Distance (order of Impact During (Low, Medium, Significance Residual Impacts VSR Between VSR magnitude only) Afteruse Phase High) before Mitigation (Insubstantial, and Source(s) (Negligible, Small, Measures Slight, Moderate, Intermediate, (Insubstantial, Substantial) Large) Slight, Moderate, Substantial) Residential VSRs VR 65 Stanley 7km High Intermediate High Moderate to Slight to Substantial Insubstantial Recreational VSRs VR 66 Shan Tei Long (Mt. 2km Few Large High Substantial Moderate to Stenhouse), Lamma Island Substantial VR 67 Chung Hom Kok Park 7km Few Intermediate High Moderate to Slight Substantial VR 55 Fa Peng Beach 10km Few Small High Moderate Insubstantial VR 11 Area for Boating, Fishing, 0.5km - 10km Few Large High Substantial Slight Diving and other water sports (varies) activities Travelling VSRs VR 49 Maritime Vessels 0.5km - 10km Few Moderate Moderate Moderate Insubstantial (varies)
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18. PILLAR POINT VALLEY NORTH LANDFILL 18.1 Basic Information Project Title 18.1.1 Pillar Point Valley North Landfill (PPVNL). Nature of Project 18.1.2 The Project would form a new landfill, designated as PPVNL, which would occupy a valley located between the existing un-restored Pillar Point Valley Landfill and the restored Siu Lang Shui Landfill (Figure 18.1). 18.1.3 The PPVNL would be designed to accept waste from the time at which the disposal capacity of the existing/extended landfills has been reached. 18.1.4 If it is assumed that the PPVNL would be constructed as a “stand alone” facility, procured through competitive tendering, construction works would be as described in Section 3.4 (Part A). In addition specific issues for the PPVNL would include: - Delivery of waste by road-vehicle.
Location and Scale of Project 18.1.5 The site is located in the North West New Territories (NWNT) some 2km west of Tuen Mun, overlooking Urmston Road and Lantau Island. Excepting the Pillar Point Valley Landfill and the Siu Lang Shui Landfill, there are no developments (industrial or residential) within 700m of this site. 18.1.6 Ground elevations within the proposed site vary from +120mPD to +320mPD. 18.1.7 The PPVNL is located within the boundary of a “Land Borrow Area” designated on Lands Department Plan No. DL16-SO that is entirely within the Castle Peak Firing Range (also known as Defence Lot No. 16). 18.1.8 More than 700m to the south of the PPVNL lies Tuen Mun Area 38, the last phase of which is currently under reclamation. This area is currently occupied by a temporary public filling barging point and CED is planning to establish and operate a fill bank for temporary stockpiling of public fill between early 2003 and 2005. The site is earmarked for a number of permanent facilities in the future, including an aviation fuel facility, a petrochemical plant, a recovery park and other waste management facilities. To the east of Area 38 is the River Trade Terminal and to the west lies the Shiu Wing Steel Mill and Castle Peak Power Station. Black Point Power Station is located approximately 3.5km to the north of the PPVNL. Although not yet confirmed, a Waste-to-Energy Facility (WEF) has been proposed at Ha Pak Nai, which is about 4km to the north of the PPVNL. 18.1.9 The PPVNL occupies an area of some 100ha, with a net void capacity in the region of 65Mcum, subject to final contouring, and assuming balanced earthworks. An access road would be required from Lung Mun Road to the landfill.
History of Site 18.1.10 Due to its inclusion within the Castle Peak Firing Range, the site is relatively undisturbed and has not been developed in any way. Consequently, there is little history to report. 18.1.11 This site is currently within Defence Lot No. 16 for use by the Garrison. It is not envisaged that this site would be available for landfill development in the short term. However, the Firing Range is a potential area for landfill development. Consequently this site is being considered as a possible long-term site for development as a landfill in the event that some areas of the “Defence Lot” are released for other uses. There is precedent for this as both the Pillar Point Valley Landfill and the WENT Landfill encroach into the “Defence Lot”.
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Number and Types of Designated Projects Covered 18.1.12 The PPVNL would be a Designated Project under the following Schedules of the EIAO:
• G1 - A landfill for waste as defined in the Waste Disposal Ordinance (Cap 354) • G4 - A waste disposal facility for refuse.
18.2 Outline of Planning and Implementation Programme 18.2.1 A generic outline for the planning and implementation is summarised in Section 3.5 (Part A), and a specific outline programme for the PPVNL is shown in Figure 18.2. 18.2.2 There is no statutory plan for the area in which this site is located. However the landfill would require the construction of a new access road to the landfill that would cross a “Green Belt” zone, on the draft Tuen Mun Outline Zoning Plan No. S/TM/16, to the south of the site. In addition the waste reception area and leachate treatment plant would fall partially within the “Green Belt” zone. 18.2.3 Other than the designation of this area as being in the Castle Peak Firing Range (which is a “Defence Lot”), there are no other identified uses for this site; however a portion of this “Defence Lot” adjacent to the closed Pillar Point Valley Landfill has been designated as a “Land Borrow Area”. 18.3 Possible Impacts on the Environment 18.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the PPVNL are outlined below. Figure 18.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 18.1 and 18.2.
Air Quality 18.3.2 There are no ASRs within 500m of the site or the access road to the site. Residential developments are located at a lower elevation some 700m to the west and Tuen Mun is located approximately 2km to the east. This area of Hong Kong is subject to investigation for a number of industrial related developments. There are a number of industrial developments located 700m to the south, including those at Tuen Mun Area 38 such as the Permanent Aviation Fuel Supply Facilities and a C&D Materials Sorting Facilities. 18.3.3 The site lies at an elevated position within a hilly area, with turbulent air flow. Given the distance to the nearest ASRs, it is unlikely that there would be any noticeable impacts. Within 5km from the site, Castle Peak Power Station, Shiu Wing Steel Mill, River Trade Terminal and Green Island Cement Works are located west of the site; these and other existing and proposed industrial facilities in Tuen Mun Area 38 may give rise to cumulative impacts. Black Point Power Station and a proposed WEF, STF and ACTF are located north of the site and may also give rise to cumulative air quality impacts. However, although the site is located within the Deep Bay Airshed, it is unlikely that air would stagnate within the vicinity of the site because of prevailing winds. 18.3.4 This is a land based site and will have road access only. The cumulative distance to be travelled from the existing network of inland RTSs (eg. NWNT RTS, Shatin RTS) to the site is estimated to be 99km. Given the fact that only road vehicles can be used for waste delivery, the total emissions of air pollutants to this site will likely be higher than a marine based site of equivalent capacity.
Noise 18.3.5 The landfill development, including access roads and reception area, has the potential to cause the following noise impacts:
• Excavation, site formation and general construction activities. • Heavy mobile plant used during operation.
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• Waste collection vehicles, etc. entering and leaving the site during operation. • Fixed plant noise.
18.3.6 There are unlikely to be any significant noise implications associated with this site because there are no NSRs within 300m of the site or the access road. 18.3.7 During construction and operation phases, it is possible that activities could continue into, or even through, the night-time period. This would depend upon day-to-day landfill operations and the overall landfill development programme employed by the landfill contractor. 18.3.8 Impacts from the various existing and proposed facilities in Tuen Mun Area 38 were considered, but are too far distant from the site to cause cumulative impacts.
Water Quality 18.3.9 The landfill development, including the access road and reception area, has the potential to cause the following water quality impacts: • Sediment-laden runoff escaping from the site during landfill construction. • Effluent from the leachate treatment plant during operation and aftercare. • Accidental leachate breakout into surface water drainage during operation and aftercare.
18.3.10 The site is located in a hilly area and while there is potential for sediment-laden and leachate- contaminated runoff during construction, the fact that the majority of construction works would be undertaken within a “bowl” should negate this potential. During operation and aftercare, surface water drainage channels would be constructed to prevent significant uncontrolled run- off from the completed landfill surface area. 18.3.11 The assumption is made that for an operating landfill all discharges would be controlled, so that there would be no water quality impacts during operation. However, this assumption should be addressed in further detail, including a risk assessment (e.g. of a leachate breakout incident) during the detailed EIA stage of the project. The design of the landfill would have to incorporate environmental protection orientated designs to cater for such potential incidents. 18.3.12 Any discharges from the PPVNL would ultimately enter the North West WCZ, where a “zero discharge” policy is not in force, instead of Deep Bay.
Waste Management / Disposal Impacts 18.3.13 Given the remote location of the site, the conceptual design has provided for a material balance within the site, i.e., there is no significant import to site or export from site of materials. 18.3.14 The operation of the landfill would include:
• Local deliveries of MSW and other waste from the Tuen Mun area by road • Waste delivered by road from NWNTRTS
18.3.15 Depending on other facilities then in place:
• Waste could also be delivered to this site by road from STTS • Waste could also be delivered to this site by private waste hauliers from elsewhere in the SAR
18.3.16 An option would also existing for waste delivered by sea to the existing WENT Landfill waste reception area to be transferred by road to the PPVNL either by a dedicated road across the WENT Landfill and the Castle Peak Firing Range, or by using the public highway via Nim Wan Road and Lung Mun Road.
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18.3.17 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. 18.3.18 All waste materials would need to be stored, handled and transported in an agreed and appropriate manner that complies with the Waste Disposal Ordinance (Cap 354) and subsidiary regulations such as the Waste Disposal (Chemical Waste) (General) Regulation. For this assessment it is assumed that potential impacts from polluting goods would be controlled through appropriate design and management systems. 18.3.19 This site can only be accessed by road and thus all waste delivery will be by road vehicle. The potential GHG emissions (per kg of waste transferred) from territory-wide waste delivery to this site will likely be high compared to an equivalent the marine based site.
Ecology 18.3.20 The site is located within the Castle Peak Firing Range and so has been relatively undisturbed for a number of years. The site comprises a steep-sided valley with two ephemeral streams running roughly northeast to southwest and merging towards the middle of the site. 18.3.21 The general environs of Castle Peak have long been recognized as being of conservation value by virtue of the flora of the area. The Tsing Sham Tsuen SSSI, designated in 1976 due to its unique tree flora, is located 3km east-northeast of the site. According to the SUSDEV21 study, the ecological value of this SSSI is graded as “medium”. The Castle Peak SSSI, designated in 1980 also due to its floristic value, is located approximately 1.5km northeast of the site. In particular, this SSSI supports well-developed populations of the Balloon Flower Platycodon grandiflora, which is protected under the Forestry Regulations, (subsidiary of the Forestry and Countryside Ordinance (Cap. 96)), whilst the ravines below the summit provide a habitat for rare shrubs. The ecological value of this SSSI is graded as “high”. 18.3.22 Vegetation is well established all over the site, generally comprising mixed scrub with grass, but also with pockets of tall scrub and semi-mature woodland. Given the undisturbed nature of the site, and its ecological linkage with other undisturbed habitat particularly to the north and east, it is likely to provide habitat for a range of fauna. Likewise, linkage with undisturbed vegetated areas to the north, east and west (including the two SSSIs) means there is potential for flora of conservation significance to be present within or adjacent to the site. 18.3.23 The coastal waters off Pillar Point are a habitat for the Chinese White Dolphin, Sousa chinensis. The Sha Chau & Lung Kwu Chau Marine Park is located some 4km west of the point of discharge of the site’s streams into the coastal waters. The waters around the Marine Park are also part of an ecologically important fisheries area. However, impacts on coastal resources are not anticipated, as water quality control measures will be incorporated during site formation to control surface run-off, and into site design to ensure there are no operational impacts on coastal waters.
Fisheries 18.3.24 The site is located some 1.5km inland from the reclaimed coastline at Tuen Mun Area 38, and is situated in an undisturbed upland area. As such there are no mariculture or aquaculture activities at the site that would be directly affected by any development thereat. 18.3.25 The closest site of aquaculture activity to the site is at Ha Pak Nai, located some 5km due north of the site. There is no natural drainage from the site in this direction and so there would be no impacts on aquaculture activities.
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18.3.26 The coastal waters off Tuen Mun Area 38 form the northern boundary of the “Northeast Lantau” fish spawning ground that is bound by Chek Lap Kok in the south, “the Brothers” in the east and the Sha Chau & Lung Kwu Chau Marine Park in the west. The area has been identified as an important spawning ground for commercial species including Leiognathus brevirostrus, Lateolabrax japonicus and Clupanodon punctatus, and has been recommended for protection.1 Commercially valuable shrimp species such as Penaeus penicillatus and Metapenaeus ensis are also present in the area.2 The Sha Chau & Lung Kwu Chau Marine Park is of particular importance as a fish spawning ground, and artificial reefs have been deployed here to enhance fisheries resources.3 18.3.27 As with ecology, impacts on coastal fisheries resources are not anticipated, as water quality control measures will be incorporated during site formation to control surface run-off and into site design to ensure there are no operational impacts.
Cultural Heritage 18.3.28 There are numerous grave sites in the area surrounding the PPVNL, although none are considered to be of historic or cultural significance. Should any such graves be encountered during the development of the PPVNL then these would be dealt with in accordance with standard procedures – this has been a common occurrence during the development of the strategic landfills and so no particular difficulties are envisaged. 18.3.29 There have been no detailed archaeological surveys undertaken at the PPVNL and given the undeveloped nature of the site and also the steep topography, it is less likely that significant relics would be located in this area. However, this should be investigated further in later studies.
Landscape and Visual 18.3.30 Landscape Planning Designations - The area of the PPVNL is not covered by any planning designations reflecting landscape values and so there will be no impacts on these values. The landfill reception area and the southern section of the access road, however, are located within the Green Belt as indicated by the Draft Tuen Mun OZP S/TM/16 (see Figure 18.4). Resulting impacts will be slight at all phases of the project. 18.3.31 Landscape Resources - The PPVNL is a terrestrial site and as a consequence there is an impact upon landscape resources. The key resources consist of:
• Steep natural slopes. • Grassland/ scrub and grassland and tall scrub. • Short lengths of stream courses which may be ephemeral.
18.3.32 Resources are shown in Figure 18.3A. As a consequence of the existing land use of the site, the degree of disturbance to the area has been limited to the loss of vegetation and erosion of soil areas caused by “badlands” and the Castle Peak Firing Range. Given the (relatively) limited size of the site, the PPVNL will result in slight impacts during the construction/operation phase and during the afteruse phase.
1 Environmental Resources Management (1998). Fisheries Resources and Fishing Operations in Hong Kong Waters. Report to the Agriculture and Fisheries Department, Hong Kong Government.
2 AFCD (2001). Marine Parks Database: Sha Chau & Lung Kwu Chau [http://parks.afcd.gov.hk/marine/mpark/scmp.htm]
3 AFCD (2001). Fisheries: Artificial Reefs Programme. [http://www.afcd.gov.hk/fish/ard/webpage/English/index.html].
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18.3.33 Landscape Character - The PPVNL falls within the Castle Peak Uplands LCA, a predominantly upland landscape dominated by Castle Peak (Tsing Shan) at 553mPD (Figures 18.3 and 18.4). The PPVNL will have the effect of creating an elongated summit with two closely linked peaks at 320mPD in the area, by the filling of an existing valley. The presence of a second peak in close proximity to Castle Peak, will have the effect of reducing its dominance within the surrounding landscape. However, the presence of the two existing landfills will tend to reduce the impacts on landscape character. Impacts during the construction/operation phase will therefore be moderate with slight impacts during the afteruse phase. 18.3.34 VSRs - Because of the location and elevated nature of the site, there are no large areas of population within the primary visual envelope (Figures 18.5 and 18.6). Visual sensitive receivers are listed in Tables 18.3 and 18.4. Across much of the envelope close to the site, views are significantly interrupted by the natural landform, the location of roads in artificial cutting, and existing vegetation. A small number of hikers in the vicinity of Castle Peak will experience significant visual impacts during the construction / operation of the landfill. There are no visual impacts on residential VSRs within the primary envelope. For all other VSRs visual impacts will be slight or insubstantial. After completion of restoration, the site will appear as a largely vegetated landform. The change in topography, however, will mean that the impacts on the hikers on and in the vicinity of Castle Peak will be moderate. For the remainder of visual VSRs the visual impacts will be reduced to insubstantial. 18.3.35 Mitigation - Mitigation measures are outlined in Part A and are shown in Figure 18.8.
Landfill Gas 18.3.36 There are no sensitive receivers within 250m of the PPVNL. Furthermore, the PPVNL is outside the 250m LFG consultation zones for the Pillar Point Valley Landfill and the Shiu Lang Shui Landfill. 18.3.37 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source, e.g., exporting via pipeline to be used as a substitute for “towngas” or LPG in surrounding communities, is not considered practical. These options have also not been considered practical for the LFG generated by the existing Pillar Point Valley Landfill and Shiu Lang Shui Landfill. However, LFG would be used as an on-site energy source. 18.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 18.4.1 Environmental design measures have been identified in Section 3.8 (Part A) and generic approaches to mitigating impacts on different environmental parameters are outlined in Section 5 (Part A). Specific environmental mitigation requirements for the PPVNL, including the access road and reception area, are outlined below but are subject to the findings of the EIA:
Air Quality 18.4.2 It is unlikely that any construction, operation or aftercare activities would have a significant impact on ASRs, and so no air quality mitigation measures are recommended at this stage, other that good site practice.
Noise 18.4.3 Noise generated by the construction of the PPVNL is not expected to cause any significant impact, since there are no NSRs within 300m of the site. 18.4.4 During construction, the topography of the site provides natural acoustic shielding, nevertheless, good site practice is recommended.
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18.4.5 During operation, it is likely that the most significant noise source would be from landfill- related vehicular traffic on the internal haul roads and the site access road from Lung Mun Road. Minor sources would be from on-site plant such as leachate treatment works, pumps, generators and the flare. In the event that changes in future land uses surrounding the site itself result in predicted noise impacts which exceed the appropriate standards, the design and layout should locate fixed noise sources away from NSRs and maximize the shielding effects of other non-noise emitting landfill related facilities. In the event that future NSRs are found to be affected by vehicles using the access route from Lung Mun Road, possible noise mitigation measures as per Annex 13 S.6 of EIAO-TM, for example noise bunding and barriers, should be investigated. To mitigate the most significant sources, the location of fixed plant should be carefully reviewed and permanent noise barriers could possibly be placed alongside roads where necessary.
Water Quality 18.4.6 The PPVNL would include a leachate treatment works. Leachate would initially be passed through the leachate treatment plant to reduce the BOD and ammonia levels. Effluent from the leachate treatment plant could then be discharged to the nearby Pillar Point Sewage Treatment Works for further treatment. Effluent from the Pillar Point Sewage Treatment Work is discharged by outfall into marine waters. The leachate treatment facilities would be designed to achieve the water quality parameters set under the WPCO TM Standards, Environmental Permit and contract specifications. 18.4.7 Surface water would be collected by perimeter drains around the landfill and pass through settlement lagoons before being discharged into existing stream courses and surface water drains. All discharge points would include monitoring facilities to establish that WPCO TM Standards and any standards set under the Environmental Permit and contract specifications were being achieved. The settlement lagoons would be used to remove any suspended solids, and oil interceptors would be used to remove oil and grease.
Waste Management 18.4.8 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Ecology 18.4.9 There are no areas of ecological importance that require specific environmental protection. 18.4.10 However, as vegetation clearance would be necessary for development of the PPVNL, revegetation works should be undertaken at suitable locations and using suitable native species. The exact location of revegetation activities and the species to be used should be determined at the detailed EIA Study stage of the project after a detailed vegetation survey and habitat mapping has been conducted. The revegetation works should adopt a “landscape ecology” approach in that planting proposals should be co-developed by competent landscape architect with support from a botanist / vegetation ecologist.
Fisheries 18.4.11 As the site is totally land based, there will be no impacts to marine fisheries. Furthermore, there is no (freshwater) fish-farming in the area that would be disturbed by the PPVNL.
Cultural Heritage 18.4.12 There are no known areas of cultural heritage importance that require specific protection measures.
Landscape & Visual 18.4.13 It is envisaged that the restored site would not be wholly incompatible with the surrounding natural landscape. If the restored landfill is to be made available for low-intensity recreational use, hiking trails and panoramic lookout points with viewing pavilions could be provided.
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18.5 Summary 18.5.1 A summary of the SEA for the PPVNL is provided in Tables 18.1 and 18.2:
Table 18.1: Pillar Point Valley North Landfill SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O There are no ASRs within 500m of the site or the new land use access road. 2 Presence of topographic O High hills, such as Castle Peak, separate the PPVNL features which could decrease from major urban areas, such as Tuen Mun. It is unlikely or exacerbate impacts that dust or odours would accumulate around the PPVNL. 3 Occurrence of meteorological O Prevailing winds are from the south-west. The conditions which could predominant wind direction would blow over the Castle exacerbate impacts Peak Firing Range, away from populated areas. 4 Cumulative impacts of relevant - Relevant emissions are present within 5km, from the emissions (TSP (construction), existing Pillar Point Valley Landfill and Shiu Lang Shui NOx, CO, SO2 – LFG Flare) Landfill. Other sources of emissions in the vicinity are the taking into account ambient existing Castle Peak Power Station, the Green Island conditions Cement Works, the Shiu Wing Steel Mill, the Black Point Power Station, together with proposed waste management facilities in Tuen Mun Area 38 and Ha Pak Nai. However AQOs are unlikely to be exceeded. 5 Total Emissions of Air Pollutants - - The site is only accessible by road and hence all waste from the territory-wide waste will be delivered by road vehicles. transportation between the RTSs and the site 6 Overall impact - Overall it is considered that the PPVNL would not cause detrimental air quality impacts. This is generally because the location of the site means that sensitive receivers are more than 500m away and therefore unlikely to be affected. However, given the fact that road-based transportation will be used for waste delivery, the overall impact is considered to be ‘Negative – Low’.
Noise Assessment
1 Distance to areas of noise O There are no NSRs within 300m of the site. sensitive land use 2 Topographic features O As the PPVNL is separated from the major urban areas by hills, noise impacts upon them would be negligible. (only applicable if there are Impacts would thus be within acceptable levels. NSRs within 300m) 3 Cumulative impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. This site is remote from NSRs and there are no surrounding developments within 300m which could cause cumulative impacts. 4 Overall Impact O Overall it is considered that the PPVNL will have minimal noise impacts on surrounding NSRs due to its remote siting. Therefore a ‘Neutral’ impact overall.
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Impacts Score Commentary
Water Quality Assessment
1 Watercourse diversion - The natural streams within the valley would be destroyed, not diverted, by the PPVNL. Although they are not considered as major watercourses, they would nevertheless be lost to development. 2 Potential for sediment O The landfill would be constructed in a relatively steep contaminant release area and so sediment-laden run-of is a potential issue during construction. The landfill would be designed to minimise run-off, and to channel it through control measures, such as sedimentation tanks, prior to discharge, thereby removing any suspended contaminants. 3 Potential impacts on WSRs O Any effluents arising from the construction and operation of the site would be treated on site and then discharged (including increase or through Pillar Point Sewage Treatment Works to the exceedance of WQOs) North-west WCZ. As such, impacts would be minimal. 4 Potential impacts on O Groundwater may be present as perched water tables groundwater above rockhead and in fissures within the underlying rock mass. However, within the vicinity of the site it is believed that, in common with most of Hong Kong, groundwater is not utilised as a resource. Impacts on background groundwater quality would be minimised by design of a suitable impermeable liner for the landfill, that would prevent discharge of significant quantities of contaminants into groundwater beneath the site. 5 Potential cumulative impacts - There are a number of existing and planned facilities (potential for concurrent projects within the vicinity of the PPVNL, all of which ultimately to exacerbate preceding discharge into the North-west WCZ. impacts) 6 Overall impact O A number of watercourses would be lost within the landfill bowl and there is a possibility of sediment entering the local watercourses. There are unlikely to be any significant impacts to the receiving water body or to groundwater resources, however, there may be a cumulative impact when other facilities are considered. Therefore a ‘Neutral’ impact overall.
Waste Management Assessment
1 Balance of materials O The PPVNL has been designed to have a balance of cut and fill. (surplus / deficit of public fill needed for landfill development) 2 GHG emissions from mode of - - There is no marine access to the site and so all waste transport for delivery of waste to would be delivered by road vehicle. the site from RTSs 3 Overall impact - Although the PPVNL has been designed to achieve a material balance, there is no marine access and so all waste would have to be delivered by road. The overall impact on waste management is considered to be ‘Negative – Low’.
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Impacts Score Commentary
Ecological Assessment
1 Potential for secondary O The nearest “Areas of Absolute Exclusion” to the site are environmental impacts on “Areas the SSSIs at Tsing Sham Tsuen (3km east-northeast) of Absolute Exclusion” and at Castle Peak (1.5km northeast). Both of these SSSIs are designated for their floristic value and the distance separation between these and the site means there is no potential for secondary impacts. 2 Affects an important habitat - - The majority of this site is mixed scrub and grassland, with pockets of semi-mature woodland. The area is presently undisturbed and given the ecological linkage with areas of conservation importance to the east, north and west, there is good potential that the site holds some importance as a habitat. There are also two watercourses within the site boundary that are good examples of their type. 3 Affects a species of conservation - There are known species of conservation importance in importance nearby areas. However, because access to the site is prohibited due to unexploded ordinance, it has not been possible to visit and examine the site, nevertheless, the ecological linkage with undisturbed areas nearby means there is good potential that flora of conservation significance is present. There is also some potential that fauna of conservation importance may use the site (e.g., mammals and birds) or, if utilizing adjacent areas, may be disturbed by site formation and operation activities. 4 Potential for cumulative O There are no known developments or activities in the ecological impacts on sites of area that would lead to cumulative ecological impact. recognised value 5 Overall impact - Development of a landfill on this site would adversely affect an otherwise undisturbed habitat that supports a mosaic of habitat types. There is potential that flora of conservation importance are within the site, whilst fauna may use the site directly or use the adjacent undisturbed areas. As the site is in a valley area with no other activities planned, there is no potential for cumulative impacts. The overall impact has been assessed as ‘Negative – Low’.
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Impacts Score Commentary
Fisheries Assessment
1 Potential for secondary O Land based site – no impact anticipated. environmental impacts on “Areas
of Absolute Exclusion” 2 Affects an important mariculture/ O Land based site – no impact anticipated. fisheries resources (including
spawning / nursery ground) 3 Potential for cumulative fisheries O Land based site – no impact anticipated. impacts on sites of recognised
value 4 Overall impact O This is a land based site and so there will be no fisheries impacts, i.e., ‘Neutral’.
Cultural Heritage Assessment
1 Important cultural (Declared, O There are no important cultural / archaeological sites that Deemed or Graded sites) / would be affected by the PPVNL. archaeological sites 2 Potential for archaeological O It is considered unlikely that there is any potential for value archaeological value within the site boundary. 3 Potential for cumulative heritage O There are no important cultural / archaeological sites that Impacts on sites of recognised would be affected by other developments. value 4 Overall impact O It is unlikely that the PPVNL would cause any impacts to cultural or archaeological sites. Therefore, the overall impact has been assessed as ‘Neutral’.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for landscape - The area of the PPVNL is not covered by any planning planning and designations designations reflecting landscape values and so there will be no impacts on these values. The landfill reception area and part of the leachate treatment facilities, and the southern section of the access road, however, are located within a Green Belt zone. 2 Landscape resources - The site is terrestrial and as a consequence there is an impact upon landscape resources. The key resources consist of: - • steep natural slopes • grassland/ scrub and grassland and tall scrub • short lengths of stream courses which may be ephemeral These are not sensitive resources and given the (relatively) limited size of the landfill, resulting impacts will be low. 3 Landscape character - The site falls within the Castle Peak Uplands LCA, a predominantly upland landscape dominated by Castle Peak (Tsing Shan) at 553mPD. The presence of a second peak in close proximity to Castle Peak, will have the effect of reducing slightly its dominance within the surrounding landscape. However, the presence of the existing landfill site will tend to reduce the impacts on landscape character. 4 Visual - Because of the location of the site, there are no large areas of population close to the site. Within the primary visual envelope those most affected will be recreational VSRs on Castle Peak. Other affected VSRs are all distant and include occupational/ travelling receivers on the Shekou, Lantau Island and Tuen Mun Ferry, Hong Kong International Airport and the Airport Expressway on Lantau Island. 5 Overall Impact - Overall landscape and visual impacts will be ‘Negative – Low’, for the following reasons: • There are no landscape planning designations covering the disposal site, although designations (Greenbelt) do cover the area of the proposed access road and reception area. • There are no significant landscape resources at the disposal site; • Landscape character is already somewhat degraded by the existing Pillar Point Valley Landfill; • Visual receivers are few in number, distant from the disposal site and often transient.
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Impacts Score Commentary
Landfill Gas Assessment
1 Distance between the new / O There are no sensitive receivers within 250m. extended landfill and SRs 2 Number of receivers within 250m O There are no sensitive receivers within 250m. (i.e. Consultation Zone) 3 Man-made / natural pathways for O There are no known man-made or natural pathways LFG migration between the PPVNL and any sensitive receivers. 4 Additional utilisation of LFG to O There are no potential off-site users of LFG at this time. reduce GHG emissions 5 Overall impact O There are no particular issue regarding LFG and so the impact is considered to be ‘Neutral’.
Table 18.2: Summary of Pillar Point Valley North Landfill SEA
Overall Impacts Score Commentary Overall Air Quality Impact - Negative – Low Overall Noise Impact O Neutral Overall Water Quality Impact O Neutral Overall Waste Management Impact - Negative – Low Overall Ecological Impact - Negative – Low Overall Fisheries Impact O Neutral Overall Cultural Heritage Impact O Neutral Overall Landscape & Visual Impact - Negative – Low Overall Landfill Gas Impact O Neutral
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Table 18.3 Assessment of Significance of Visual Impacts for Pillar Point Valley North Landfill During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
VSR Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Construction (Low, Medium, High) before Mitigation Residual Impacts VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR21 Tung Chung 10.5km Many Negligible High Insubstantial Insubstantial
Occupational Receivers VR22 Hong Kong International 6.6km Moderate Negligible Moderate Insubstantial Insubstantial Airport VR23 Shekou, Lantau Island and 4km Very Few Small Low Slight Insubstantial Tuen Mun Ferries
Recreational Receivers VR10 Castle Peak 1.3km Few Large Low Moderate Moderate VR20 Lantau Peak 15km Few Negligible Low Insubstantial Insubstantial VR24 Sunset Peak 14.6km Few Negligible Low Insubstantial Insubstantial
Travelling Receivers VR25 Hong Kong International 6.6km Many Small Low Slight Insubstantial Airport VR26 Airport Expressway 9.5km Moderate Small Low Slight Insubstantial VR27 Shekou, Lantau Island 4km Moderate Small Low Slight Insubstantial and Tuen Mun Ferries
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual sensitive receivers shown in Figure 18.5.
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Table 18.4 Assessment of Significance of Visual Impacts for Pillar Point Valley North Landfill During Afteruse Phase (Year 10 after Restoration) (Note: All impacts adverse unless otherwise noted)
Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Afteruse (Low, Medium, High) before Mitigation Residual Impacts
VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR21 Tung Chung 10.5km Many Negligible High Insubstantial Insubstantial
Occupational Receivers VR22 Hong Kong International 6.6km Moderate Negligible Moderate Insubstantial Insubstantial Airport VR23 Shekou, Lantau Island and 4km Very Few Small Low Slight Insubstantial Tuen Mun Ferries
Recreational Receivers VR10 Castle Peak 1.3km Few Intermediate Low Moderate Moderate VR20 Lantau Peak 15km Few Negligible Low Insubstantial Insubstantial VR24 Sunset Peak 14.6km Few Negligible Low Insubstantial Insubstantial
Travelling Receivers VR25 Hong Kong International 6.6km Many Small Low Slight Insubstantial Airport VR26 Airport Expressway 9.5km Moderate Small Low Slight Insubstantial VR27 Shekou, Lantau Island and 4km Moderate Small Low Slight Insubstantial Tuen Mun Ferries
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual sensitive receivers shown in Figure 18.5.
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19. NENT LANDFILL EXTENSION SITE 19.1 Basic Information Project Title 19.1.1 NENT Landfill Extension Site (NLES). Nature of Project 19.1.1 The Project would form an extension to the existing NENT landfill, designated as the NLES, which would occupy the valley in which the existing NENT Landfill Stockpile and Borrow Area is located (Figure 19.1). The NLES would be designed to accept waste from the time at which the disposal capacity of the existing NENT Landfill has been reached. 19.1.2 The landfill extension would require two rockfill bunds, constructed from material excavated on-site, to raise the perimeter low points located to the north and south to required levels. The maximum depth of fill in the eastern corner is envisaged at about 90m. In this location, the final restoration level would be +230mPD. The maximum elevation of the final restoration profile would be +245mPD along the south easternmost boundary. 19.1.3 If it is assumed that the NLES would be constructed as a “stand alone” facility, procured through competitive tendering, construction works would be as described in Section 3.4 (Part A). In addition specific issues for the NLES would include:
• Delivery of waste by road-vehicle.
19.1.4 However, if the project was constructed as an “addition” to the existing NENT Landfill, procured through a negotiated extension with the existing landfill contractor, then the following facilities could be shared, thus reducing the scope and cost of the works:
• Weighbridges, wheel washing and vehicle cleaning facilities. • Facilities for recording and processing waste inputs and other site activities. • Accommodation for Government supervisory staff and Independent Consultants. • Accommodation for landfill contractor’s staff. • Plant garaging, workshop and maintenance facilities. • Container handling areas. • Mess and welfare facilities. • Fire fighting facilities. • Site security and fencing.
Location and Scale of Project 19.1.5 The NLES is located partially on the site of the NENT Landfill Stockpile and Borrow Area that was formed to the east of the existing landfill as part of the original site development of the NENT Landfill. 19.1.6 The extension site covers an area of 70ha and would accommodate a landfill with a capacity of 19Mcum. 19.1.7 For the most part of the NLES would fall within the existing NENT Landfill Stockpile and Borrow Area zoned “Other Specified Uses (Landfill)” on the approved Wo Keng Shan OZP No. S/NE-WKS/3. However, part of the site would be outside the Stockpile and Borrow Area and extend into the surrounding “Green Belt” zone. 19.1.8 Approval from the relevant policy bureau(x) and the Town Planning Board would need to be sought on this scheme. In particular, approval from the Town Planning Board on the rezoning of the affected “Green Belt” zone for the NLES would be required. The current OZP would therefore need to be amended accordingly.
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History of Site 19.1.9 The existing NENT Landfill was commissioned in 1995 and receives waste mainly by road from the North East New Territories, and the Kowloon Bay and Shatin Refuse Transfer Stations. This inland landfill occupies approximately 67ha and is located in a remote valley 2km west of Robin’s Nest (Hung Fa Leng), 6km north-east of Fanling in the very northern part of the New Territories, and is adjacent to the Closed Boundary Area to the north. 19.1.10 The site was first developed under a CED Contract CV/91/05, which formed an initial area of the site ready for waste deposition, and also created a Stockpile and Borrow Area, where spoil from the initial excavation was stored for later reuse. CED’s contractor also constructed the waste reception area and a 2km access road and water main from Sha Tau Kok Road to serve the landfill (Contract CV/90/07). These works are referred to in the NENT Landfill Contract as “Advance Works”, and also included advance construction of a leachate treatment plant. 19.1.11 The NENT Landfill Contract EP/SP/12/92 was awarded by EPD to Far East Landfill Technologies Ltd (FELT) (referred to subsequently as “the landfill contractor”) in 1994; and was the last in the series of three Strategic Landfill Contracts to be awarded on a Design- Build-and-Operate basis.
Number and Types of Designated Projects Covered 19.1.12 The NLES would be a Designated Project under the following Schedules of the EIAO:
• G1 - A landfill for waste as defined in the Waste Disposal Ordinance (Cap 354) • G4 - A waste disposal facility for refuse.
19.2 Outline of Planning and Implementation Programme 19.2.1 A generic outline for the planning and implementation is summarised in Section 3.5 (Part A), and a specific outline programme for the NLES is shown in Figure 19.2. 19.3 Possible Impacts on the Environment 19.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the NLES are outlined below. Figure 19.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 19.1 and 19.2.
Air Quality 19.3.2 The nearest ASRs within 500m of the landfill extension are a number of village houses in Tong To Shen Tsuen and Wo Keng Shan. Beyond this, lies Lin Ma Hang which is situated some 900m from the site and is unlikely to be affected by the extension. 19.3.3 The site lies within a hilly area, with turbulent air flow, however there are no significant topographic features between the site and the ASRs. Although the site is located within the Deep Bay Airshed, it is unlikely that air would stagnate within the vicinity of the site because of prevailing winds. 19.3.4 Notwithstanding the adjacent village of Tong To Shan, the site is located in a remote area, with few known developments (existing or planned) except the NENT Landfill. However, given the preliminary nature of this SEA, the status of this issue should be reviewed in subsequent, more detailed, studies. 19.3.5 It should also be noted that previous studies (NENT Landfill Final Report in 1988 and the Supplementary Environmental Impact Assessment in 1995) on the existing NENT Landfill reported that no significant air quality impacts were expected.
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19.3.6 This is a land based site with road access only. The cumulative distance to be travelled from the existing network of inland RTSs (eg. NWNT RTS, Shatin RTS) to the site is estimated to be 96km. Given the fact that only road vehicles can be used for waste delivery, the total emissions of air pollutants to this site will likely be higher than an equivalent marine based site.
Noise 19.3.7 The landfill development has the potential to cause the following noise impacts:
• Excavation, site formation and general construction activities. • Heavy mobile plant used during operation. • Waste collection vehicles, etc. entering and leaving the site during operation. • Fixed plant noise.
19.3.8 Given the remote location of the site, there are few NSRs in the area, (see Figure 19.1). 19.3.9 An assessment of potential noise impacts arising from the construction and landfilling operations of the existing NENT landfill was carried out as part of a Supplementary Environmental Impact Assessment1 (SEIA) by the landfill operator in 1995. Predictions of noise impacts from vehicular delivery of waste, landfilling activities as well as fixed plant, (i.e. LFG flare, leachate treatment plant) indicated that cumulative noise impacts from these sources would exceed recommended noise limits at NSRs surrounding the landfill, such as at Wo Keng Shan, Ping Yeung, Ha Heung Yeung and Tsung Yeung. The NLES, however, is located at some distance away from of most of these NSRs. Of the previously assessed NSRs, only Wo Keng Shan remains within 300m of the NLES. However, Tong To Shan Tsuen now falls just within 300m of the northeast boundary of the site. 19.3.10 The noise impact assessment for the existing landfill was based on a number of assumptions in terms of phasing of works and included a worst case scenario that involved minimal down- time and continuous works activities. Notwithstanding this, impacts were predicted to be mitigable to within acceptable levels. 19.3.11 A combination of temporary and permanent noise mitigation measures was recommended in the SEIA for the existing landfill, including mobile noise barriers and temporary noise bunds for various landfill phases. Whilst outside the scope of SEIA study, it was also recommended that vehicular noise impacts to Wo Keng Shan could be mitigated by construction of permanent noise barriers along the public access road at the entrance to the site. 19.3.12 In the event, however, noise barriers along the site entrance have not been required and the experience to date has shown that noise levels at the existing landfill are within acceptable levels. Potential noise impacts associated with the NLES are likely to include those associated with vehicle movements on the residents at Wo Keng Shan, as well as noise from landfilling operations on residents at Tong To Shan Tsuen. 19.3.13 During construction and operation phases, it is possible that activities could continue into the night-time period, depending upon day-to-day landfill operations and the overall landfill development programme employed by the landfill contractor. However, it should be noted that under the currently proposed arrangements, landfill activities outside of normal working hours are not envisaged. 19.3.14 Given the isolated nature of villages in the area, the number of affected dwellings is likely to be small. Whilst experience at the existing landfill indicates no significant impacts, on the basis of the previous EIA for the landfill development further more detailed investigation is likely to indicate that predicted impacts require mitigation.
1 ERM Hong Kong (1995) NENT Landfill: Supplementary Environmental Impact Assessment, Far East Landfills Technologies
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Water Quality 19.3.15 The landfill development has the potential to cause the following water quality impacts:
• Sediment-laden runoff escaping from the site during landfill construction. • Effluent from the leachate treatment plant during operation and aftercare. • Accidental leachate breakout into surface water drainage during operation and aftercare.
19.3.16 The stream located in the valley of Lin Ma Hang is close to the NLES and is a WSR by virtue of its ecological sensitivity (see below). No other WSRs have been identified in the vicinity. Uncontaminated stormwater discharges are not considered to be a potential source of impact. 19.3.17 Although the NLES is located in a hilly area and while there is potential for sediment-laden and leachate-contaminated runoff, the majority of construction works would be undertaken within a “bowl” and so runoff would not be possible. During operation and aftercare, any uncontrolled surface run-off or “leachate breakout” would be intercepted by the surface water drainage channels and so would not cause impacts to any nearby WSRs. 19.3.18 Based on the findings of the EIA and SEIA for the existing NENT Landfill (NENT Landfill Final Report in 1988 and the Supplementary Environmental Impact Assessment in 1995), it is understood that groundwater resources in the area may be used for irrigation purposes and/or may also feed into local surface watercourses. 19.3.19 On the basis of experience gained from the development and management of the existing strategic landfills, the assumption is made that all discharges from the NLES would be controlled, such that the risk of water quality impacts during construction and operation would be managed to acceptable levels. This assumption could be further addressed by including a risk assessment (e.g. of a “leachate breakout” incident) during the detailed EIA. The design of the NLES would ensure environmental protection is maintained.
Waste Management / Disposal Impacts 19.3.20 Given the remote location of the site, the conceptual design has provided for a material balance, i.e., there is no significant import to site or export from site of materials. To construct the NLES, about 8.5Mcum of material would need to be excavated. The majority of this material would then be utilised to form the southern bund (2Mcum), the northern bund (3Mcum) and to elevate the areas of the base to the required levels (1.5Mcum). The surplus 2Mcum are required for a 1.5m thick layer of material for capping of the waste, for the base and sidewall lining system, and a 1m thick leachate drainage layer. This material balance has also taken into consideration the daily cover requirements. 19.3.21 With regard to the transportation of waste to the site, given its inland location all waste would be delivered by road vehicle and so the benefits of marine transportation cannot be realised. 19.3.22 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc. 19.3.23 All waste materials would need to be stored, handled and transported in an agreed and appropriate manner that complies with the Waste Disposal Ordinance (Cap 354) and subsidiary regulations such as the Waste Disposal (Chemical Waste) (General) Regulation. For this assessment it is assumed that potential impacts from polluting goods would be controlled through appropriate design and management systems. 19.3.24 This site is located inland and can only be accessed by the existing road. As such, road vehicles will be the only means for waste delivery to the site. Given the use of road vehicles, the potential GHG emissions (per kg of waste transferred) from territory-wide waste delivery to this site will likely be high.
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Ecology 19.3.25 There are a number of ecologically important / sensitive sites in the environs of the NLES. Details of these and the potential for adverse effects of the NLES upon them are provided as follows. Figure 19.1 shows the locations and extent of the ecologically sensitive areas discussed in relation to the NLES. 19.3.26 According to the recommendations of the Territorial Development Strategy Review prepared by the Planning Department, the majority of upland area of Robin’s Nest has been identified as a potential country park. The surrounding area is botanically significant and known for its diversity of plant species. The boundary of the potential Country Park abuts the boundary of the existing NENT Landfill only at the south-east. 19.3.27 The area surrounding the existing NENT Landfill is botanically significant and known for its diversity of plant species. There is a particularly diverse tall scrub / semi-mature woodland habitat growing in three of the steep ravines that surround the existing landfill site, which offer protection from hill-fires2 These three areas are to the immediate northwest, north and east of NENT (see Figure 19.1) and would not be affected by the NLES. 19.3.28 The upland plateau vegetation in the immediate vicinity of the existing landfill supports a number of shrub species that collectively form a habitat that is likely to be of ecological value. Vegetation around the southeast of the existing landfill that may be affected by development of the NLES includes Baekia frutescens, Rhodomytus tormentosa, Rhaphiolepsis indica and Liquidambar formosana. In this respect, any vegetation clearance to facilitate the development of the NLES would need to be preceded by a detailed vegetation survey that could subsequently be used to guide compensatory planting. 19.3.29 To the north of site is the Lin Ma Hang Lead Mine SSSI. This is one of the most important bat colonies in Hong Kong and would be located within the boundary of the proposed Robin’s Nest Country Park. However, this site is located almost 1km from the NLES and is unlikely to be adversely affected. 19.3.30 Lin Ma Hang Stream is a typical lowland freshwater stream and has a rich collection of primary freshwater fish including five rare and uncommon species. Whilst it would seem that the main area of importance for these fish species is the lowland waters, developments that may affect any part of the stream catchment may potentially lead to an adverse impacts on the water quality downstream. There is a buffer of approximately 200m between the southern- most boundary of this stream (i.e., the stream’s headwaters) and the northern-most extent of the NLES. Nevertheless, it considered close enough to warrant consideration of additional provisions (in the works contract) to safeguard the stream during construction of the NLES. Details of suitable ecological and stream water quality control measures are provided in Section 19.4 and shown in Figure 19.1. 19.3.31 There is a “fung shui” woodland, with several sizeable Camphor trees, located near to Wo Keng Shan village, and Bamboo Bats have been reported to have roosted there. However, this area is around 500m south of the existing NENT Landfill and the NLES does not encroach further south than the existing landfill. Therefore the “fung shui” woodland and the habitat for Bamboo Bats are unlikely to be adversely affected. 19.3.32 Figure 19.1 shows the locations and extent of the ecologically sensitive areas discussed above in relation to the NLES. Apart from the ecologically significant sites and species of conservation importance, there are no other reported significant habitats or species of conservation importance within 500m of the NLES. Furthermore, there are not believed to any species of conservation importance that would be disturbed by the NLES.
2 BMT (2002). NENT Landfill Site: Terrestrial Monitoring. Annual Summary Report for the Year 2001.
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19.3.33 It is noted that drainage improvement works have been proposed at Lin Ma Hang, under the Drainage Master Plan Study in the Northern New Territories. Although the findings of that study are not available to the Consultants, cumulative drainage impacts are considered unlikely, given that Lin Ma Hang village is more than 500m from the NLES. This issue should be confirmed during the detailed EIA stage.
Fisheries 19.3.34 As the site is totally land based, there will be no impacts to marine fisheries. Furthermore, there is no (freshwater) fish-farming in the area that would be disturbed by the NLES.
Cultural Heritage 19.3.35 Commissioned by the Antiquities and Monuments Office of the Leisure and Cultural Services Department, the Hong Kong Institute of Archaeology conducted an archaeological survey and assessment in the project area of the NLES during August and September 2001. During the survey, the archaeological team identified a “Settlement District” mainly distributed in the northern part of the project area with Tong To Shan as its centre, and dated from the first half of the 17th century to the early 20th century. Tong To Shan is situated immediately adjacent to the NLES. Figure 19.1 indicates the areas of archaeological importance. 19.3.36 Within the Tong To Shan Settlement District, a total of 91 stone structural features were found mainly distributed in the Tong To Shan area in the east of the northern project area as well as 40 graves in the Ngong Tong area in the west of the northern project area. 19.3.37 The stone features, all built of roughly cut mountain rocks, can be classified into three major categories based on their shape and inferred function, namely building, slope-protection wall and path. The category of building includes remains of nine houses and one cistern. The houses are all characterised with rectangular shape and stone-built walls but they vary in size, room-number, height and wall decoration, suggesting different functions in use, such as residential house, animal pen or storage room. The cistern is two-layered and roughly square in shape. 19.3.38 Seventy-four slope-protection walls were found in the Settlement District. The function of the slope-protection walls would have been to protect the hill slopes from soil erosion and collapsing. But, judging from the characteristics of location, artefact association and topographic setting, these stone walls could also have been used in different ways, to protect either the terraced fields, the banks of water courses or the flat activity areas on the slope in and around the residential area. 19.3.39 Six paths were identified and were covered on the surface with flat stone slabs. Two of these paths are quite long, stretching about 300m into the surrounding woodland. One is located in the Ngong Tong area and the other, in the Tong To Shan area. 19.3.40 Forty grave sites were found in the Settlement District. Of this number, 14 graves appear to have been moved to some other site, leaving only grave pits or scattered bricks. Among the remaining graves, 20 are dated, including seven original graves and 13 re-built graves. The original graves are dated from 1874 to 1930; the re-built graves are dated from 1743 to 2000, but all the graves that have been rebuilt in the 20th century have used the original grave tablets, some dating back to the Qing dynasty.
Landscape and Visual 19.3.41 Landscape Planning Designations - the area of landscape in which the site lies is designated “GB” and “OU” under the Wo Keng Shan OZP (S/NE-WKS/3) (Figure 19.4). The entire site area is also zoned “Conservation Area” under the Territorial Development Strategy Review 1995 Landscape Strategy. Resulting impacts on landscape planning intentions will be moderate during construction/operation and slight during afteruse.
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19.3.42 Landscape Resources - The landscape elements of the site are already significantly prejudiced by the presence in that area of the existing NENT Landfill Stockpile and Borrow Area and comprise:
• Steep natural slopes. • Grassland / scrub and grassland and tall scrub. • Small areas of abandoned agricultural land. • Short lengths of stream course (which may be ephemeral).
19.3.43 Landscape resources are shown in Figure 19.3A. Given the extensive disturbance that has been caused by the Stockpile and Borrow Area of the existing NENT Landfill, resulting impacts on landscape resources (all of the above) will be slight during construction/operation of the landfill and during afteruse. 19.3.44 Landscape Character - The site falls within the Hung Fa Leng Uplands LCA in north-east New Territories, a predominantly natural upland landscape dominated by the peak of Robin’s Nest (Hung Fa Leng) at +492mPD (Figure 19.3). The NLES will have the effect of slightly degrading this natural landscape. However, the fact that there is already a significant landfill in this landscape will in part offset impacts on landscape character. During construction/operation of the extension, impacts on landscape character will be moderate. During afteruse, impacts on landscape character will be slight. 19.3.45 VSRs - Because of the location of the site, there are no large areas of population close to the site (Figure 19.5). Visual sensitive receivers are shown in Tables 19.3 and 19.4. Across much of the visual envelope close to the site, views are significantly interrupted by vegetation, buildings or small landforms. A small number of residential VSRs in villages and hikers close to the extension site will be exposed to substantial visual impacts during construction/operation phase (Figure 19.6). Future residents and those working in Fanling North, Ping Che and Ta Kwu Ling NDAs, of which the need and timing of development is still subject to review, will experience slight impacts. For all other VSRs, during construction/operation of the landfill, visual impacts will be slight or insubstantial. During afteruse, the landfill will appear as a largely vegetated upland landform and residual visual impacts will be reduced to insubstantial for most VSRs and slight for certain residential and recreational VSRs. 19.3.46 Mitigation - Landscape and visual mitigation is outlined in Section A and is illustrated in Figure 19.8.
Landfill Gas 19.3.47 The NLES is within the 250m consultation zone of the existing NENT Landfill and so a LFG Hazard Assessment would be required during the EIA stage. There are no sensitive receivers (targets) or pathways within 250m of the NLES – the upper reaches of the Lin Ma Hang Stream are not considered to be a LFG “target”. Therefore, there are no potential off-site landfill gas hazards. 19.3.48 Although the NLES would generate significant amounts of LFG during the operation and aftercare phases, it has been assumed that the landfill would be designed as a containment landfill with an efficient LFG collection system that would eliminate off-site migration. 19.3.49 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source, e.g., exporting via pipeline to be used as a substitute for “towngas” or LPG in surrounding communities, is not considered practical. 19.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 19.4.1 Environmental design measures have been identified in Section 3.8 (Part A) and generic approaches to mitigating impacts on different environmental parameters are outlined in Section 5 (Part A). Specific environmental mitigation requirements for the NLES are outlined below but are subject to the findings of the EIA:
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Air Quality 19.4.2 It is unlikely that any construction, operation or aftercare activities would have a significant impact on ASRs, and so no air quality mitigation measures are recommended at this stage, other that good site practice.
Noise 19.4.3 Noise generated by the construction of the NLES is not expected to cause a significant increase to that generated by the operation of the existing NENT Landfill. There are few NSRs within 300m of the site, however, on the basis of the existing SEIA for landfill development, noise levels could exceed standard limits unless mitigated. 19.4.4 During construction, the topography of the site provides natural acoustic shielding, nevertheless, good site practice is recommended. This would include using only powered mechanical equipment with built-in acoustic shielding and not using percussive piling. Where necessary, temporary noise barriers and /or earth bunds could be constructed. 19.4.5 During operation, it is likely that the most significant noise source would be from landfill- related vehicular traffic on the internal haul roads and the access road. Minor sources would be from on-site plant such as leachate treatment works, pumps, generators and the flare. To mitigate the most significant sources, the location of fixed plant should be carefully reviewed and permanent noise barriers could possibly be placed alongside roads where necessary particularly in the vicinity of Wo Keng Shan at the entrance to the landfill.
Water Quality NENT Leachate Management 19.4.6 The existing leachate treatment plant occupies an area of approximately 4ha, and is situated approximately 1km to the north of the existing waste reception facilities. The facility comprises leachate storage and aeration lagoons and an ammonia stripper, prior to discharge to Shek Wo Hui Sewage Treatment Works (SHWSTW). Upgrading of leachate treatment facilities at the NENT Landfill has been required in order comply with the WPCO TM standards for effluents discharged into foul sewers leading to Government STWs, regarding total nitrogen concentration. An ammonia stripper has been installed in order to allow the standard of 200mg/L for total nitrogen to be met. 19.4.7 The current quantities of leachate produced by the NENT Landfill range from 800 cum/day in the dry season to 1,200 cum/day in the wet season. Following completion of the landfill and final capping, this has been predicted to fall to approximately 100 m3/day. The decrease in flow is expected to happen relatively rapidly once waste placement ceases and final capping is in place. 19.4.8 Leachate will be generated from the NLES as soon as waste placement commences. The quantity of leachate generated by the NLES has been estimated at 600 – 1,300 m3/day, which is approximately the same as from the existing NENT Landfill. The overall quantities of leachate generated from the two landfill sites can be minimised by:
• Ensuring smooth handover between the landfills, such that there is only a limited period of “double-tipping” when waste is being placed in both sites. • Ensuring that capping of the existing NENT Landfill is carried out to a high standard and in the shortest possible time. • Commencing placement of waste at NLE and capping at the existing NENT Landfill at the start of the dry season, so capping can be completed, or be well advanced, by the beginning of the wet season. • Increased leachate recirculation within the existing NENT Landfill following capping to increase leachate retention time and hence smooth out any temporary peak in leachate generation.
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19.4.9 It is possible that, in the period immediately following closure of the existing NENT Landfill and opening of the NLES, the combined average leachate flows may exceed 1,000 m3/day. For flows of this magnitude, the permitted standard for discharge to STWs is 100mg/L for total nitrogen (i.e. half of the currently permitted concentration of 200mg/L). If additional treatment is carried out to meet this standard, the overall nitrogen loading would remain constant compared to the existing situation even if the quantity of leachate generated were to double, which is not expected. 19.4.10 Since there may be an overlap period during which leachate is being generated both from the NLES and from the existing NENT Landfill prior to final capping, it may be necessary to increase leachate treatment capacity to cope with the temporary increase in flow as described above. This could be achieved either by increasing capacity at the existing plant or installing a separate plant for the NLES. Increased treatment capacity may be put into place at the NENT site by installing:
• Additional aeration lagoon capacity. • Additional ammonia stripping capacity.
19.4.11 The current NENT Leachate Treatment Plant occupies approximately 4ha. Assuming a similar area of 4ha is required, the only suitable areas of undeveloped flat land within close proximity to the NLES are to the north (within the Closed Boundary Area) or at Wo Keng Shan to the south of the existing waste reception facilities. 19.4.12 If these sites are not available, an area for the plant could be created within EPD’s existing GLA adjacent to the existing waste reception facilities. The current waste transfer facilities within the Waste Reception Area are likely to become redundant following completion of the marine transfer facilities for the South East Kowloon Refuse Transfer Station that will replace the Kowloon Bay Refuse Transfer Station. Space will therefore be available within this area, and additional space could be formed by earthworks in the immediate vicinity if required. Ammonia strippers occupy a relatively small space, so the overall space required will be determined primarily by the size of the aeration lagoons. There would be the potential to site temporary aeration lagoons or tanks within the footprint of the NLES. Although they would ultimately need to be relocated to allow the void capacity to be fully utilised, the life expectancy of the landfill is such that temporary facilities may be able to operate for a number of years prior to relocation. 19.4.13 If leachate treatment was addressed in this manner, the effluent from the NLES Leachate treatment plant would be pumped to the existing plant where the effluent would be discharged into the intake structure of the rising main to the SWHSTW. 19.4.14 Currently, treated leachate is pumped to SWHSTW via a rising main for final treatment. Pumping is carried out almost continually from 0700 to 2300 hours, at a rate of between 700 and 1,200 cum/day. SWHSTW discharges into the Deep Bay catchment area. Government policy severely restricts the input of pollutants into the sensitive environment of Deep Bay. 19.4.15 Additional pumping capacity may be required during the overlap period, when leachate is being produced from the NENT Landfill and the NLES. The capacity of the existing pipeline would depend on the pressure rating of the pipe, and other factors such as the length of pipe, the level of particulates in the leachate, and the provision of surge tanks to prevent potential pipe failure due to surging. The capacity of the pipe is unlikely to be a constraint on the rate of leachate pumping.
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19.4.16 The existing flow varies from 800 – 1,200 cum/day. SWHSTW currently treats approximately 70,000 cum/day (annual average), so the leachate from the existing NENT Landfill represents approximately 2% of flow. Following capping of the existing NENT Landfill, the total combined leachate flows is expected to stabilise rapidly to a level approximately 100 cum/day higher than currently. There is the possibility that SWHSTW will be upgraded to a capacity of 160,000 cum/day. The additional 100 cum/day of leachate represents approximately 0.15% of existing capacity or 0.06% of potential future capacity, in either case a very small proportion. Should double-tipping be necessary for a short time, the effect on capacity of SWHSTW will be equally small. Pollution loading in Deep Bay would remain unchanged. 19.4.17 If required, additional pre-treatment may be carried out to reduce nitrogen loading in the effluent on a pro-rata basis, to maintain a zero net gain in nitrogen loading from this source. This could be achieved by setting a lower outlet ammonia concentration for the ammonia stripper. Any increase in loading of metals or trace organics is unlikely to be measurable in the final effluent from the sewage treatment works, and would be well within the normal range of variability. NENT Sewerage 19.4.18 The existing landfill and the NLES fall within the Deep Bay Catchment Area. Since the pollution loading of the Deep Bay and its catchment areas have well exceeded its assimilative capacity, any new facilities or development have to demonstrate that they do not impose an additional pollution loading onto Deep Bay. 19.4.19 In the vicinity of the existing landfill and the extension site, there is no sewage infrastructure development. Therefore all new developments are required to provide on-site sewage treatment facilities. 19.4.20 Sewage from the existing NENT Landfill (from site offices and facilities) is currently fed into the aeration lagoons, where it is mixed with leachate, treated and pumped to SWHSTW. The amounts of sewage generated are very small in comparison with quantities of leachate. It is proposed that sewage from the NLES would be disposed of in a similar manner. The net increase in sewage arising is expected to be minimal in comparison with daily leachate generation, and is not expected to give rise to a measurable increase in pollutant loading. NENT Surface Water Drainage 19.4.21 Following restoration, drainage would run off from the landfill surface to the perimeter. The perimeter drainage channels would direct the flow to two main discharge areas located at the toe of the northern and southern bunds respectively. The drainage to the south would then follow existing drainage courses presently running through the landfill infrastructure whereas drainage to the north runs into stream courses flowing into the Sham Chun River approximately 1.5km to the north. 19.4.22 All water that has passed through areas containing waste should be classed as leachate, and will therefore be treated and discharged as described above. Storm water run-off generated during construction and operation of the NLES is not classed as leachate, but may contain elevated concentrations of suspended solids, as well as oils and other contaminants from road surfaces. Treatment of run-off water may be carried out using settlement tanks to remove suspended solids, and oil interceptors to remove oil and grease. 19.4.23 The quality of the discharge would be regulated by means of a Discharge Consent issued in accordance with the WPCO TM for discharge to inland waters. Standards for discharge into Group B Inland Waters (the general category for watercourses in largely agricultural areas) are 30mg/L of suspended solids and 10mg/L of oil and grease.
Waste Management 19.4.24 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
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Ecology 19.4.25 Due to the close proximity of the Lin Ma Hang Stream and the boundary of the proposed Robin’s Nest Country Park to the NLES, special provision should be included within the contract documents to ensure that these sensitive areas are afforded maximum protection. Suitable measures that may be taken to protect the upper reaches of the Lin Ma Hang stream include construction of a cut-off trench or channel along the northern boundary of the potential NLES site, and that should be subject to more detailed investigation at the EIA stage as to their practicability. This would divert drainage / run-off from the eastern portion of landfill extension into storm drains outside the Lin Ma Hang stream catchment via adequately designed sediment removal facilities (i.e., silt / sediment traps). 19.4.26 The various measures outlined in the ProPECC Note 1/94 on Construction Site Drainage, and particularly the various means to control surface run-off, should also be implemented. 19.4.27 As vegetation clearance would be necessary for development of the NLES, revegetation works should be carried out at suitable locations and using suitable native species. The exact location of revegetation activities and the species to be used should be determined at the detailed EIA Study stage of the project after a detailed vegetation survey and habitat mapping has been conducted. The revegetation works should adopt a “landscape ecology” approach in that planting proposals should be co-developed by a competent landscape architect with support from a botanist / vegetation ecologist.
Fisheries 19.4.28 As the site is totally land based, there will be no impacts to marine fisheries. Furthermore, there is no (freshwater) fish-farming in the area that would be disturbed by the NLES.
Cultural Heritage 19.4.29 The Tong To Shan Settlement District is a site of great cultural and historical significance. This settlement district has been preserved well, reflecting many aspects of human life in Hong Kong during a period of nearly 300 years, and this district, therefore, can become an ideal field for the multi-disciplinary study of the late historical period in Hong Kong history. 19.4.30 Because of the high cultural heritage value of the Tong To Shan Settlement (TTSS) district, the primary approach to developing the NLES has been to avoid the archaeological site altogether. However, due to its location and the need to provide a minimum landfill capacity to achieve the aims of the Study, total avoidance of the TTSS is not considered to be a viable option. As such the schematic design prepared under this Study has been developed to reduce the overlap between the site boundary for the NLES and the TTSS as far as practicable (see Figure 19.1). However, whilst impacts have been minimised, in order to accommodate the NLES it is likely that some of the graves in the Ngong Tong area as well as portions of two stone paths and one slope protection wall in the TTSS would be directly impacted. 19.4.31 In addition to the revisions to the boundary of the NLES, a number of options have been considered to minimise the impacts upon the TTSS, these are discussed and described in Appendix II and include:
• Preservation Insitu by Burial Beneath the Landfill: This approach leaves the affected relics where they are, but assumes they could be exhumed later if desired. However this option is constrained due the fact that the relics are at ground-level and are vulnerable to damage from construction of the landfill. Any later exhumation, would also damage the integrity of the landfill, and could result in uncontrolled release of leachate through the base liner.
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• Preservation Insitu Using a Cavern Structure: This approach leaves the affected relics where they are, and allows access to them through a cavern specially constructed in the earth embankment to the north of the landfill. This option, would allow the relics to be preserved insitu, without being damaged. However, there are a number of uncertainties in relation to cost-effectiveness, practicality and overall feasibility. In addition, significant protection measures would be required to mitigate the hazards associated with landfill gas ingress into the caverns. • Preservation by Detailed Recording, Burial and Display: This approach includes the preparation of detailed photographic, cartographic and video records of the affected relics, with selected artefacts displayed in a location and manner, which promotes community understanding and knowledge of Hong Kong’s archaeology and cultural heritage. The remaining portion of the site would then be used for construction of the NLES. This option is the most feasible and practicable approach, although it is also the least preferred, as it would result in the loss of some relics, as well as a portion of the TTSS for future investigations.
19.4.32 As part of an EIA and the development of the design, opportunities to maximise the preservation of archaeological features of the TTSS should be pursued. For those portions of the stone footpaths and slope protection walls in the TTSS that cannot be preserved insitu, a suitable plan for rescue excavation should be drawn up for approval by AMO. In the Ngong Tong area, grave sites that cannot be avoided by the NLES should be surveyed and any considered to be worthy of preservation (eg. due to early dating or unique structural styles) should be included in the rescue excavation plan. All excavation works should be completed (to the satisfaction of AMO) prior to commencement of any construction works. All graves and portions of slope protection walls should be recorded and photographed during excavation. 19.4.33 The arrangements for ensuring the long-term management of the archaeological features is subject to agreement between the project proponent and EPD.
Landscape & Visual 19.4.34 It is envisioned that the restored site would blend in with the restoration of the original NENT Landfill, and that both should blend in with the surrounding natural landscape. If the restored landfill is to be made available for low-intensity recreational use, hiking trails and panoramic lookout points with viewing pavilions could be provided.
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19.5 Summary 19.5.1 A summary of the SEA for the NLES is provided in Tables 19.1 and 19.2:
Table 19.1: NENT Landfill Extension SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive - >10 village houses in Tong To Shan Tsuen and Wo Keng land use Shan are within 500m of the site. 2 Presence of topographic O The site lies within the Deep Bay Airshed. The site is features which could decrease enclosed by hills, and generally experiences wind. It is or exacerbate impacts unlikely that dust or odours would accumulate around the site. 3 Occurrence of meteorological O Winds blow both towards and away from ASRs. No conditions which could prevailing wind direction has been identified. exacerbate impacts 4 Cumulative impacts of relevant - The site is located in a remote area, with no known emissions (TSP (construction), developments (existing or planned) within 5km of the NOx, CO, SO2 – LFG Flare) NLES. During construction of the NLES, the existing NENT taking into account ambient Landfill would be operating, however, during operation of conditions the NLES the original landfill would be closed. 5 Total Emissions of Air Pollutants - - The site is only accessible by road and hence all waste will from the territory-wide waste be delivered by road vehicle. transportation between the RTSs and the site 6 Overall impact - The NLES is in a remote location, far from urban areas and there are few habitations in the vicinity. There are no known developments planned for the area and so cumulative impacts are not expected to be severe. Road traffic will be the only mean accessing to the site (for waste delivery). The overall impact on air quality is therefore considered to be ‘Negative – Low’.
Noise Assessment
1 Distance to areas of noise - >10 village houses in Tong To Shan Tsuen and Wo Keng sensitive land use Shan are within 300m of the site. 2 Topographic features - Line of sight to Wo Keng Shan & Tong To Shan Tsuen. The site is surrounded by hills, and which are expected to (only applicable if there are provide attenuation of noise. NSRs within 300m) 3 Cumulative impacts of O The site is located in a remote area, with no known developments within 300m developments (existing or planned) within 300m of the NLES. During construction of the NLES, the existing NENT Landfill would be operating, however, during operation of the NLES the original landfill would be closed. 4 Overall Impact O / - The NLES is in a remote location, far from urban areas and there are few habitations in the vicinity. There are no known developments planned for the area and so cumulative impacts are not expected to be severe. The NSRs are predicted to require some form of mitigation. The overall impact on noise levels is therefore could be ‘Neutral / Negative – Low’.
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Impacts Score Commentary
Water Quality Assessment
1 Watercourse diversion O No watercourses diversions are likely to be necessary during the works. 2 Potential for sediment - The landfill would be constructed in a relatively steep area contaminant release and so sediment-laden run-off is a potential issue during construction. The landfill would be designed to minimise run-off, and to channel it through control measures, such as sedimentation tanks, prior to discharge, thereby minimising potential impacts. 3 Potential impacts on WSRs - The valley of Lin Ma Hang Stream is close to the landfill boundary and is considered to be a sensitive receiver. (including increase or exceedance of WQOs) 4 Potential impacts on O Based on the findings of the EIA for the existing NENT groundwater Landfill, it is understood that groundwater resources in the area may be used for irrigation purposes. Impacts on groundwater quality would be minimised by design – e.g. use of an impermeable liner that would prevent the discharge leachate into groundwater beneath the site. 5 Potential cumulative impacts O There are no other known projects in the vicinity that would (potential for concurrent projects exacerbate the impacts generated by this project. to exacerbate preceding impacts) 6 Overall impact O The NLES is in a remote location, far from urban areas, and so the local watercourses are of high quality. Of particular note in this regard is the Lin Ma Hang Stream. There are no known developments planned for the area and so cumulative impacts are not expected to be severe. The overall impact on water quality is considered to be ‘Neutral’.
Waste Management Assessment
1 Balance of materials O The NLES has been designed to have a balance of cut and fill. (surplus / deficit of public fill needed for landfill development) 2 GHG emissions from mode of - - There is no marine access to the site and so all waste transport for delivery of waste to would be delivered by road vehicle. the site from RTSs 3 Overall impact - The NLES is in a remote location, and this has necessitated a material balance. However, there is no marine access and so all waste would have to be delivered by road. The overall impact on waste management is considered to be ‘Negative – Low’.
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Impacts Score Commentary
Ecological Assessment
1 Potential for secondary - The site is adjacent to a proposed Country Park at Robin’s environmental impacts on ‘Areas Nest. of Absolute Exclusion’ 2 Affects an important habitat - / -- The site is some 200m from the upper reaches of the ecologically sensitive Lin Ma Hang Stream. Particular care will be needed in order to prevent impacts upon this sensitive habitat. There is also potential for transient effects upon an important terrestrial habitat in the area (i.e. ecologically important vegetation). However, with adequate planning and implementation, potential impacts can likely be compensated for in the medium-term. 3 Affects a species of conservation - Unless mitigated, it is possible that the works could impact importance upon sensitive species of freshwater fish within Lin Ma Hang Stream. With mitigation however, it is considered that impacts on the downstream water quality (and hence aquatic resources within) can be avoided. 4 Potential for cumulative O Cumulative impacts are considered unlikely, since there ecological impacts on sites of are not believed to be any significant developments in the recognised value vicinity of the site, other than the existing NENT Landfill. 5 Overall impact - The NLES is in a remote location, far from urban areas, and so the local ecology is of high quality. There are particular concerns regarding the proposed Robin’s Nest Country Park and Lin Ma Hang Stream, although the project boundary has been revised to avoid direct footprint impacts. Also, the effectiveness of mitigation is considered to be high. The overall impact on ecology is thus considered to be ‘Negative – Low’.
Fisheries Assessment
1 Potential for secondary O Land based site – no impact anticipated. environmental impacts on ‘Areas
of Absolute Exclusion’ 2 Affects an important mariculture/ O Land based site – no impact anticipated. fisheries resources (including
spawning / nursery ground) 3 Potential for cumulative fisheries O Land based site – no impact anticipated. impacts on sites of recognised
value 4 Overall impact O This is a land based site and so there will be no fisheries impacts, i.e., ‘Neutral’.
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Impacts Score Commentary
Cultural Heritage Assessment
1 Important cultural (Declared, - - The Tong To Shan Settlement District is immediately Deemed or Graded sites) / adjacent to the site. Some graves in the Ngong Tong area archaeological sites are located within the site. 2 Potential for archaeological - The site area has been occupied from the 17th Century value onwards and it is likely that additional archaeological structures, albeit minor, remain undiscovered in the area. 3 Potential for cumulative heritage O There is a limited potential for cumulative impacts. Impacts on sites of recognised value 4 Overall impact - - The NLES site contains a number of archaeological sites, whilst the majority of the Tong To Shan Settlement District is now excluded from the footprint of the site, the cultural heritage impact is considered to be ‘Negative – High’.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for landscape - On completion of the project, vegetation will take some planning and designations years to establish and landforms will never look totally natural. The area of landscape in which the NLES lies is designated “GB” and “OU”. The entire site area is also zoned “Conservation Area” under the Territorial Development Strategy Review 1995 Landscape Strategy. Extension of the landfill in this area will not be consistent with the landscape planning intention for the area, as it will reduce its natural characteristics further (though it should be noted that these effects will be offset considerably by the existing landfill works in the area). 2 Landscape resources - The landscape resources of the extension site are already significantly prejudiced by the presence in that area of the existing NENT Landfill Stockpile and Borrow Area, which have and will continue to degrade the landscape resources of a significant area of the proposed extension site. Given the extensive disturbance that has been caused by the borrow area of the existing NENT Landfill, the magnitude of potential impacts will be limited. 3 Landscape character - / - - On completion of the project, vegetation will take some years to establish and landforms will never look totally natural. The site falls within the Hung Fa Leng Uplands Landscape Character Area (LCA) in north-east New Territories. The NLES will have the effect of further degrading an area of natural landscape. The fact that there is already a significant landfill in this landscape will however in part offset impacts. 4 Visual - Presence of exposed refuse, earthworks, temporary slope works, vehicles and associated structures during construction. On completion, vegetation will take some years to establish and landforms will never look totally natural. The presence of gas flares will represent an incongruous visual element at all stages of the project. There are no large areas of population within the primary visual envelope and across much of the visual envelope close to the site, views toward the site are significantly interrupted by vegetation, buildings or small landforms A small number of residential VSRs in villages close to the extension site will be exposed to substantial visual impacts. For all other VSRs, visual impacts will be slight or insubstantial. After completion of restoration, the extension will appear as a largely vegetated landform.
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Impacts Score Commentary
5 Overall Impact - Overall, landscape and visual impacts will be ‘Negative – Low’, for the following reasons: The extension is not compatible with existing landscape planning intentions for the area. • Landscape resources on the site are not of particular sensitivity. • Landscape character is of medium sensitivity, and is degraded by the presence of the existing landfill. Once complete, the restored landfill will not be inconsistent with the scale or character of existing landscape. • Visual VSRs are very few in number, often distant from the extension site and often transient. • The site will eventually be restored to simulate natural landforms/vegetation, but this will take time (decades).
Landfill Gas Assessment
1 Distance between the new / O Other than buildings associated with the existing landfill, extended landfill and SRs the nearest sensitive receivers are >250m away. 2 Number of receivers within 250m O Other than buildings associated with the existing landfill, (i.e. Consultation Zone) the nearest sensitive receivers are >250m away. 3 Man-made / natural pathways for - There are believed to be man-made pathways in the LFG migration vicinity of the site, consisting of the services leading to the existing landfill. However, the pathways via these services to sensitive receivers are long and indirect. Faults are present in the vicinity of the site, but these do not lead directly to sensitive receivers. 4 Additional utilisation of LFG to O There are no potential off-site users of LFG at this time. reduce GHG emissions 5 Overall impact O There are no particular issue regarding LFG and so the impact is considered to be ‘Neutral’.
Table 19.2: Summary of NENT Landfill Extension SEA
Overall Impacts Score Commentary
Overall Air Quality Impact - Negative – Low Overall Noise Impact O / - Neutral / Negative – Low Overall Water Quality Impact O Neutral Overall Waste Management Impact - Negative – Low Overall Ecology Impact - Negative – Low Overall Fisheries Impact O Neutral Overall Cultural Heritage Impact - - Negative – High Overall Landscape & Visual Impact - Negative – Low Overall Landfill Gas Impact O Neutral
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VSR Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Construction (Low, Medium, High) before Mitigation Residual Impacts VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR72 Tong To Shan Tsuen 0.3km None N/A N/A N/A N/A (abandoned) VR73 Lin Ma Hang 0.6km Very Few Intermediate High Substantial Substantial VR74 Wo Keng Shan 0.6km Very Few Large High Substantial Substantial
VR75 Ping Yueng 1.8km Very Few Small High Moderate Moderate VR76 Ping Che 1.9km Few Small High Moderate Moderate VR77 Villages west of Ping Che 2.3km-3.5km approx Few Small High Moderate Slight Road including Ha Shan Kai Wat / Sheung Shan Kai Wat / Hung Lung Hang / Lei Uk / Tai Po Lin / Chow Tin Tsuen VR78 Villages south of Sha Tau 3.5km-5.5km approx Few Negligible High Insubstantial Insubstantial Kok Road including Kwan Tei and Ma Liu Shui San Tsuen VR79 High-rise buildings in 5km approx Very Few Small High Moderate Slight eastern Fanling VR80 High-rise buildings in 3km approx Many Small High Moderate Slight Shenzhen VR81 Future Residents of 5-6km Very Few Negligible High Insubstantial Insubstantial Fanling North NDA VR92 Residents of Heung Yuen 1.3km Few Intermediate High Moderate to Slight to moderate Wai substantial
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VSR Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Construction (Low, Medium, High) before Mitigation Residual Impacts VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Occupational Receivers VR82 Workers east of Ping Che 0.5km-2.5km Very Few Intermediate Low Moderate Slight Road VR83 Workers west of Ping Che 2km-3.5km Few Small Low Slight Insubstantial Road VR84 Military personnel in 3.8km Few Negligible Low Insubstantial Insubstantial Barracks on Sha Tau Kok Road VR85 High-rise buildings in 3km approx Many Small Low Slight Insubstantial Shenzhen VR 86 Future workers of Ping 1-2km Few Intermediate Low Moderate Slight Che / Ta Kwu Ling NDA
Recreational Receivers VR87 Hikers on Robins Nest 2km Very Few Intermediate Medium Moderate Moderate VR88 Hikers in Pat Sin Leng 3km-6km Very Few Small Medium Slight Insubstantial Country Park VR89 Hikers on Pak Tai To Yan 9.5km Very Few Negligible Medium Insubstantial Insubstantial
Travelling Receivers VR90 Ping Che Road 1.9km-2.5km Few Small Low Slight Insubstantial VR91 Sha Tau Kok Road 2.8km-5km Many Small Low Slight Insubstantial
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual sensitive receivers shown in Figure 19.5.
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Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Afteruse (Low, Medium, High) before Mitigation Residual Impacts
VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR72 Tong To Shan Tsuen 0.3km None N/A N/A N/A N/A (abandoned) VR73 Lin Ma Hang 0.6km Very Few Intermediate High Substantial Slight VR74 Wo Keng Shan 0.6km Very Few Large High Substantial Slight
VR75 Ping Yueng 1.8km Very Few Small High Moderate Insubstantial
VR76 Ping Che 1.9km Few Small High Moderate Insubstantial VR77 Villages west of Ping Che 2.3km-3.5km approx Road including Ha Shan Kai Wat/ Sheung Shan Few Negligible High Slight Insubstantial Kai Wat/ Hung Lung Hang/ Lei Uk/ Tai Po Lin/ Chow Tin Tsuen VR78 Villages south of Sha Tau 3.5km-5.5km approx Few Negligible High Insubstantial Insubstantial Kok Road including Kwan Tei and Ma Liu Shui San Tsuen VR79 High-rise buildings in 5km approx Very Few Small High Slight Insubstantial eastern Fanling VR80 High-rise buildings in 3km approx Few Small High Slight Insubstantial Shenzhen VR 81 Future Residents of 5-6km Very Few Negligible High Insubstantial Insubstantial Fanling North NDA VR 92 Residents of Heung Yuen 1.3km Few Small High Moderate Slight to Wai Insubstantial
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Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Afteruse (Low, Medium, High) before Mitigation Residual Impacts
VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Occupational Receivers VR82 Workers east of Ping Che 0.5km-2.5km Very Few Small Low Slight Insubstantial Road VR83 Workers. west of Ping Che 2km-3.5km Few Negligible Low Insubstantial Insubstantial Road VR84 Military personnel in 3.8km Few Negligible Low Insubstantial Insubstantial Barracks on Sha Tau Kok Road VR85 High-rise buildings in 3km approx Few Small Low Insubstantial Insubstantial Shenzhen VR 86 Future workers of Ping 1-2km Few Small Low Slight Insubstantial Che / Ta Kwu Ling NDA
Recreational Receivers VR87 Hikers on Robins Nest 2km Very Few Intermediate Medium Moderate Slight VR88 Hikers in Pat Sin Leng 3km-6km Very Few Negligible Medium Insubstantial Insubstantial Country Park VR89 Hikers on Pak Tai To Yan 9.5km Very Few Negligible Medium Insubstantial Insubstantial
Travelling Receivers VR90 Ping Che Road 1.9km-2.5km Few Negligible Low Insubstantial Insubstantial VR91 Sha Tau Kok Road 2.8km-5km Many Negligible Low Insubstantial Insubstantial
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual sensitive receivers shown in Figure 19.5.
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20. WENT LANDFILL EXTENSIONS SITE 20.1 Basic Information Project Title 20.1.1 WENT Landfill Extensions Sites (WLES). Nature of Project 20.1.2 The Project would form two new landfills (Figure 20.1) previously designated as:
• WENT A Landfill Extension • WENT B Landfill Extension
20.1.3 The WLES would be designed to accept waste from the time at which the disposal capacity of the existing WENT Landfill has been reached. WENT A Landfill Extension 20.1.4 The project involves formation of a new landfill, adjacent to the existing WENT Landfill by forming a series of stepped terraces, due to the steep rise in topography. The design assumes that the landfill bowl would be formed with slopes cut in a series of benches with overall gradients of 1(V) on 1.5(H) for soil and 2(V) on 1(H) for rock. 20.1.5 Because of its small capacity, it is unlikely that it would be viable to open the WENT A Extension as a completely “stand-alone” landfill under a separate contract. It is envisaged that this project would be procured through competitive tendering but with certain services provided by the existing landfill contractor. Construction works would be as described in Section 3.4 (Part A). In addition specific issues for the WENT A Extension would include:
• Delivery of waste by road-vehicle or by marine vessel.
20.1.6 The WENT A Extension could share the following infrastructure with the existing WENT Landfill:
• Weighbridges, wheel washing and vehicle cleaning facilities. • Facilities for recording and processing waste inputs and other site activities. • Accommodation for Government supervisory staff and Independent Consultants. • Leachate treatment • Container handling areas.
WENT B Landfill Extension 20.1.7 The WENT B Landfill Extension is located in the area to the west of the WENT A Landfill Extension and requires the realignment of Nim Wan Road. The project involves the formation of a series of terraces, increasing in height towards the south. 20.1.8 If it is assumed that the WENT B Extension would be constructed as a “stand alone” facility, procured through competitive tendering, construction works would be as described in Section 3.4 (Part A). In addition specific issues for the WENT B Extension would include:
• Delivery of waste by road-vehicle or by marine vessel.
20.1.9 If, however, the project was constructed as an “addition” to the existing WENT Landfill, procured through a negotiated extension with the existing landfill contractor, then a number of facilities could be shared, thus reducing the scope and cost of the works.
Location and Scale of Project 20.1.10 The site is located in the North West New Territories (NWNT) some 5km north-west of Tuen Mun, overlooking Deep Bay. The site is 175ha overall.
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20.1.11 The WENT A Landfill Extension is located in Tsang Kok valley, immediately to the west of the existing WENT Landfill. The Castle Peak Firing Range lies to the south of the existing WENT Landfill and the WENT A Landfill Extension. The valley extends at its southern end into the Firing Range; however, the project is to utilise the northern part of the valley only, with the area of waste disposal not extending into the Firing Range Proper. The WENT A Landfill Extension is a small extension, with a net void capacity of 6Mcum assuming balanced earthworks. 20.1.12 The WENT B Landfill is a significantly larger scheme then WENT A, with a net void capacity of 65Mcum, assuming balanced earthworks. 20.1.13 For the remainder of this SEA, the WENT A and WENT B will be referred to as the WENT Landfill Extensions Sites (WLES), since they are located adjacent to each other and, if selected would be investigated further together.
History of Site 20.1.14 The existing WENT Landfill was commissioned in 1993 and receives publicly collected waste from the North West New Territories by road. Waste is received by marine vessel from a number of Refuse Transfer Stations comprising Island East, Island West, West Kowloon, Outlying Islands and North Lantau. Waste is also transferred by road from the NWNT Refuse Transfer Station near Yuen Long. 20.1.15 The existing landfill also receives containerised sludges from various Sewage Treatment Works, including the Stonecutters Island Sewage Works constructed under SSDS. 20.1.16 The existing landfill is a coastal site and occupies an area of approximately 106ha. Approximately 20ha of the site was formed by reclamation from the sea, using the soil and rock excavated from the site formation for the landfill void as filling material. Some of the initial formation works were carried out under a CED contract which included an initial area of the site ready for waste deposition, formed an area of reclamation, and constructed a waste reception area, a leachate pumping station and pumping main. 20.1.17 The WENT Landfill Contract was subsequently awarded by EPD to Swire BFI Waste Services Ltd (now Swire SITA Waste Services Ltd) in 1993, and was the first of the three Strategic Landfill Contracts to be awarded on a Design-Build-and-Operate basis.
Number and Types of Designated Projects Covered 20.1.18 The WLES would be a Designated Project under the following Schedules of the EIAO:
• G1 - A landfill for waste as defined in the Waste Disposal Ordinance (Cap 354) • G4 - A waste disposal facility for refuse.
20.2 Outline of Planning and Implementation Programme 20.2.1 A generic outline for the planning and implementation is summarised in Section 3.5 (Part A), and a specific outline programme for the WLES is shown in Figures 20.2A and 20.2B.
20.3 Possible Impacts on the Environment 20.3.1 Possible impacts on the environment during the construction, operation and aftercare phases of the WLES are outlined below. Figure 20.1 provides details of identified sensitive receivers. The individual assessments are summarised in Tables 20.1 and 20.2.
Air Quality 20.3.2 There are Air Sensitive Receivers (ASRs) found within a 500m radius from the boundary of this site, with the closest being the CLP Black Point Power Station that is 400m west of the site boundary. There are other ASRs located in the village of Ha Pak Nai, which is situated 1km to the east and Pak Long and Nam Long, which are 1.8km to the south.
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20.3.3 The site lies within a hilly area, with turbulent air flow; although there are no significant topographic features between the site and the ASRs. Although the site is located within the Deep Bay Airshed (north-easterly), it is unlikely that air would stagnate within the vicinity of the site because of prevailing winds, which blow away from ASRs at Ha Pak Nai. Black Point Power Station is located just outside of the Deep Bay Airshed. A proposed Waste-to-Energy Facility is located at Ha Pak Nai, though it is yet to be confirmed. These developments will generate emissions that may be cumulative to the emissions from the WLES. It is possible that the topography will change after the completion of landfilling of the WLES and the dispersion pattern may differ. Therefore, cumulative air quality impacts due to this site should be carried out at the EIA study stage. 20.3.4 Whilst the duration of parallel operation of existing WENT Landfill and the WLES would be minimal, there is scope for cumulative odour impacts from the WLES and the existing WENT Landfill, to impact residents in Ha Pak Nai. Therefore, design and operational procedures / monitoring of the WLES should take this into account to minimise the impacts. 20.3.5 The site is located in a remote area. Existing developments include the original WENT Landfill, CLP’s Black Point Power Station (and PFA lagoons) and the Castle Peak Firing Range. Planned developments may include additional waste management and waste to energy infrastructure projects, however, these have yet to be confirmed. There are also plans to construct the Deep Bay Coastal Road along an alignment to the west and north of the existing WENT Landfill. This scheme would upgrade the existing Nim Wan Road and provide a link between the Proposed Lingdingyang Bridge (which has a tentative landfall near Black Point Power Station) and the Shenzhen Western Corridor (which has a tentative landfall to the east of the existing landfill near Ngau Hom Shek). Given the preliminary nature of this SEA, and the uncertain status of planned projects, the issue of surrounding developments should be reviewed in subsequent, more detailed, studies. The key is to develop a design that has minimal impacts. 20.3.6 The information currently available from studies for adjacent facilities indicates that the overall impacts are acceptable. Cumulative impacts would not be anticipated, however, this should be reviewed at later stage. 20.3.7 It should also be noted that previous studies (WENT Landfill Conceptual EIA in 1987 and the Supplementary Environmental Impact Assessment in 1993) on the existing WENT Landfill reported that no significant air quality impacts were expected, provided that on-site mitigation measures (predominantly dust suppression on haul roads) were fully implemented. 20.3.8 The existing WENT Landfill has both marine frontage and road access for waste delivery. It is assumed that the future WLES will utilise similar transportation arrangements. The total emissions of air pollutants and hence regional air quality impacts from waste delivery will likely be moderate, i.e. higher than a marine based site but lower than a land based site that relies entirely on road transport.
Noise 20.3.9 The landfill development has the potential to cause the following noise impacts:
• Excavation, site formation and general construction activities. • Heavy mobile plant used during operation. • Waste collection vehicles, etc. entering and leaving the site during operation. • Fixed plant noise.
20.3.10 There are unlikely to be any significant noise implications associated with this site because there are very few NSRs within 300m of the site one shrine / temple, near Tsang Tsui, is found within the site boundary, however, in the event the WLES is pursued, this would be demolished as part of the works. Identified NSRs are shown on Figure 20.1.
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20.3.11 During construction and operation phases, it is possible that activities could continue into, or even through, the night-time period. This would depend upon day-to-day landfill operations and the overall landfill development programme employed by the landfill contractor. 20.3.12 Based on previous studies (WENT Landfill Conceptual EIA in 1987 and the Supplementary Environmental Impact Assessment in 1993) the major noise impacts at Ha Pak Nai were from the reclamation works for the existing WENT Landfill. Since the WLES does not include any reclamation works near Ha Pak Nai, it is unlikely that this community would be unduly affected by the construction or operation of the WLES.
Water Quality 20.3.13 The landfill development has the potential to cause the following water quality impacts:
• Sediment-laden runoff escaping from site during landfill construction. • Effluent from the leachate treatment plant during operation and aftercare. • Accidental leachate breakout into surface water drainage during operation and aftercare.
20.3.14 The project would cause the loss of the Tsang Kok valley; limited water impacts are expected in this respect. 20.3.15 The site is located in a hilly area and while there is potential for sediment-laden and leachate- contaminated runoff during construction, the fact that the majority of construction works would be undertaken within a “bowl” should negate this potential. During operation and aftercare, surface water drainage channels would be constructed to prevent significant uncontrolled run- off from the completed landfill surface area. 20.3.16 The assumption is made that for an operating landfill all discharges would be controlled, so that there would be no water quality impacts during operation. However, this assumption should be addressed in further detail, including a risk assessment (e.g. of a leachate breakout incident) during the detailed EIA stage of the project. The design of the landfill would have to incorporate environmental protection orientated designs to cater for such potential incidents. 20.3.17 Given the current pollution loading in Deep Bay WCZ and its “zero discharge” policy, it is not desirable for any additional pollutant loading to result from the construction and operation of the WLES. Therefore, stricter performance requirements may well be necessary – these would be prepared in subsequent, more detailed studies, although some suggestions are outlined in Section 20.4.
Waste Management / Disposal Impacts 20.3.18 Given the remote location of the site, the conceptual design provides for a material balance within the site, i.e., there is no significant import to site or export from site of materials. Lining, capping and leachate drainage would require about 3Mcum of material for WENT A and 5Mcum for WENT B and these requirements would be provided for by excavation within the site. Existing PFA lagoons are included within the footprint of the WLES. It is anticipated that the PFA would remain in place during construction of the WLES, with no requirement to excavate and relocate the PFA. 20.3.19 With regard to the transportation of waste to the site, waste would be delivered by both road vehicle and by marine transport. 20.3.20 Various potentially polluting materials may be stored, handled and transported to / from the site. Examples may include chemicals for waste water/leachate treatment, waste oils, fuel for plant working on the site, etc.
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20.3.21 All waste materials would need to be stored, handled and transported in an agreed and appropriate manner that complies with the Waste Disposal Ordinance (Cap 354) and subsidiary regulations such as the Waste Disposal (Chemical Waste) (General) Regulation. For this assessment it is assumed that potential impacts from polluting goods would be controlled through appropriate design and management systems. 20.3.22 The existing WENT Landfill has both marine frontage and road access for waste delivery. It is assumed that the future WLES will utilise similar transportation arrangements. GHG impacts are considered to be moderate, i.e., higher than a marine based site but lower than a land based site that relies entirely on road transport.
Ecology 20.3.23 There are no Protected Areas within 500m of the WLES. The nearest Protected Areas are the Sha Chau and Lung Kwu Chau Marine Park (over 4km to the south west) and an SSSI at Sheung Pak Nai (3.5km to the north east). 20.3.24 The majority of this site is grassland / man made lagoons of low or no ecological value. However, there are a few small areas of mixed shrub-land and approximately 4,000sq.m of semi-mature native woodland that are of conservation value, whilst Tsang Kok Stream is largely natural. 20.3.25 The immature native woodland has developed from tall scrub habitat over the past 8 years, and as such is not yet old enough to support a diverse and stable vegetation community. The habitat is situated at the foot of a slope that adjoins an upland area that is naturally vegetated and has a similar community structure, albeit with more tall grasses. As such, a similar habitat type (tall scrub with tall grass) with a similar ecological function is well represented in the broader area. Furthermore, the proximity of the immature woodland to human activities at the existing WENT Landfill makes it most unlikely to attract sensitive birds or other wildlife. 20.3.26 Tsang Kok Stream is predominantly a natural fast-flowing and permanent stream. The natural upper and mid sections are characterized by good water quality and a typically stony substrate. The lower sections of the stream along the boundary of the existing WENT Landfill site have been culverted and are partly within the tidal range, thus influenced by marine water quality to a certain extent. The infauna of the natural stream sections is characterized by nymphs of mayfly, dragonfly / damselfly and caddisfly which are also biological indicators of good water quality. There are few fish noted in the stream. The stream community is thus moderately diverse but by no means exceptional, and the numerous other streams draining the upland area to the east would be expected to support a similar community. 20.3.27 It is noted that bird surveys for the WEF study identified that two bird species, namely the Little Grebe and the Little Ringed Plover, are of some conservation significance. Both species are essentially passage migrants, although they also have resident populations in the NWNT. They are localised but not uncommon. 20.3.28 These bird species rely on shallow wetland habitats for foraging and, in the case of the Little Grebe, nesting. The existing ash lagoons beside the WENT Landfill likely represent the principal wetland habitat in the area used by these species. As such, the loss of the lagoons for WEF formation will also eliminate this habitat and thus the attractiveness of the area to these birds. The loss of wetland habitat favoured by these species from any WENT extension would be restricted to a relatively small area for inter-tidal flats at the mouth of Tsang Kok Stream that these birds do not inhabit. 20.3.29 The EIA Report for the existing WENT Landfill refers to a population of the Pitcher Plant Nepenthes mirabilis that was found in the Tsang Kok valley, the proposed site of WENT A. All species of the genus Nepenthes are protected in the HKSAR under the Forestry Regulations (Cap. 96), primarily due to past over-exploitation for use in Chinese medicine. Of the species of Nepenthes in Hong Kong, Nepenthes mirabilis is the most widespread, being found on hillsides across the New Territories. Thus, whilst Nepenthes mirabilis is uncommon it is not considered threatened. Further investigation would be required as part of the detailed EIA for the project.
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20.3.30 This area is already disturbed by the existing landfill and Black Point Power Station. However the potential for cumulative impacts exists with a number of the planned projects, referred to earlier.
Fisheries 20.3.31 As the site is totally land based, there will be no impacts to marine fisheries. Furthermore, there is no (freshwater) fish-farming in the area that would be disturbed by the WLES.
Cultural Heritage 20.3.32 Commissioned by the Antiquities and Monuments Office (AMO) of the Leisure and Cultural Services Department, Field Archaeology Consultants conducted an archaeological survey and assessment in the WLES site during August and September 2001. 20.3.33 Tsang Tsui Archaeological Site (TTAS) was identified by AMO under the preliminary project feasibility study of a Sludge Treatment Facility in October 2000. Archaeological relics dated to late Neolithic period (c. 2500 – 1500 BC) were unearthed at the site. Furthermore, TTAS is a recorded item of, and should be protected by, the Antiquities and Monuments Ordinance, Cap.53. 20.3.34 The site covers the existing boundary of TTAS. In this connection, the study area is of high archaeological potential. In order to ascertain the archaeological potential of the landfill extension, 44 auger holes were drilled and 8 test pits were excavated in the study area including the platform just in the front of TTAS and the gentle slope at the north-west side of an abandoned fish pond. 20.3.35 The result of the archaeological survey concluded that Nim Wan was a suitable area for human settlement well before the 1970s. However, with the construction of former BBC station, the existing WENT Landfill and the PFA lagoons, part of the area with significant archaeological deposits were very much disturbed. The result of this survey further revealed that with the exception of the existing TTAS, it is very unlikely that any further archaeological remains would be found within the site. 20.3.36 As noted above, the TTAS lies in the centre of the boundary of the proposed WLES, (see Figure 20.1). In view of the overall space available in the search envelope, construction of the WLES in a manner that avoids direct impact upon the TTAS (whilst providing a viable void space to achieve the aims of the Study) is not feasible. As the TTAS would be totally buried by significant depths of waste, preservation insitu is not considered a feasible option and impacts are anticipated to be significant unless the relics are relocated.
Landscape and Visual 20.3.37 Landscape Planning Designations – Under the Territorial Development Strategy Review (TDSR) 1995 Landscape Strategy, the northern part of the site is zoned “Development Area High Landscape Value”. The zoning allows “ selected but constrained urban/suburban land use”. The southern part of the site is zoned “Conservation Area” under the TDSR “no development is envisaged’ on account of its “countryside character with extensive area of high quality natural landscape”. There is no OZP covering the site (Figure 20.4). 20.3.38 Extension of the landfill in this area will not be consistent with the landscape planning intention for the southern part of the area and resulting impacts will be slight/moderate during construction/operation and slight thereafter. 20.3.39 Landscape Resources - The landscape elements of the extension site are complex and comprise:
• An upland spur falling to sea level degraded having been subject to many minor landslips. • Degraded coastal terrain; • Existing ash lagoons
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• Stream courses which tumble down the steeply fissured slopes; • Abandoned agriculture; • Scrub and degraded industrial sites.
20.3.40 Landscape resources are shown in Figure 20.3A. The landfill will, amongst other things, affect areas of low scrub, grass, tall scrub, small areas of woodland, stream courses and degraded upland terrain. However, given the extensive disturbance already caused to the site by industrial development, roadworks and landslides and the (relatively) limited magnitude of the extension, impacts on landscape resources during construction/operation and during afteruse, will be slight. 20.3.41 Landscape Character - The WLES lies within two Landscape Character Areas (Figure 20.4). The first, the Castle Peak Uplands, is an extensive area of upland topography, which falls in a series of steep ridges and gullies to the sea. The area is generally covered in scrub and grassland although in places there are significant areas of bare earth and rock resulting from landslides and/or the presence of the Castle Peak Firing Range (Figure 20.3). 20.3.42 At the foot of the uplands lies the Western New Territories Coast, a low-lying narrow coastal landscape formerly characterised by dispersed villages and areas of arable agriculture on flatter areas, broken by areas of scrub and woodland. Whilst these features still exist, most fields have been abandoned and the area now contains a wide variety of incoherent and degraded features such as Black Point Power Station, WENT Landfill, highways development and storage yards. 20.3.43 The WLES will introduce a new feature into a landscape, which is already somewhat degraded by the existing WENT Landfill and by features such as power stations and ash lagoons on the coast. This will result in moderate impacts on landscape character during the construction / operation phase and slight impacts during afteruse. 20.3.44 VSRs - Because of the location of the site, there are no large areas of population within the primary visual envelope, although areas of Shenzhen (Shekou) have a line of sight to the WLES from some 7km (Figure 20.5). Visual Sensitive Receivers are listed in Tables 20.3 and 20.4. 20.3.45 Generally, visual impacts are offset by the indifferent visual quality of this area of the coast and in particular the presence of the existing WENT Landfill, Black Point Power Station and ash lagoons. A small number of residential VSRs in Lung Kwu Sheung Tan will be exposed to moderate visual impacts during operation of the extension. In addition, users of Nim Wan Road will also experience moderate impacts from road works and views of the landfill works (Figure 20.6). For all other VSRs, during construction/operation of the landfill, visual impacts will be slight or insubstantial. During the afteruse phase, impacts will be reduced to insubstantial for most visual VSRs, and slight for a small number of VSRs. 20.3.46 Mitigation – Mitigation measures are outlined in Part A and are shown in Figure 20.8.
Landfill Gas 20.3.47 The WLES is within the 250m consultation zone of the existing WENT Landfill and so a Landfill Gas Hazard Assessment would be required during the EIA stage. There are no sensitive receivers within this consultation zone and therefore there are no potential off-site LFG hazards. 20.3.48 It should be noted, however, that two geological fault lines run from the existing WENT Landfill, through the WLES and terminate below Black Point Power Station and, as such, may provide a natural pathway for LFG migration. 20.3.49 Although the WLES would generate significant amounts of LFG during the operation and aftercare phases, it has been assumed that the WLES would be designed as a containment landfill with an efficient LFG collection system that would eliminate off-site migration.
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20.3.50 Given the remote location of the site and the lack of any sizeable population nearby, the direct off-site use of LFG as an energy source, e.g., exporting via pipeline to be used as a substitute for “towngas” or LPG in surrounding communities, is not considered practical. 20.4 Environmental Protection Measures to be Incorporated into Design and Further Environmental Implications 20.4.1 Environmental design measures have been identified in Section 3.8 (Part A) and generic approaches to mitigating impacts on different environmental parameters are outlined in Section 5 (Part A). Specific environmental mitigation requirements for the WLES are outlined below but are subject to the findings of the EIA:
Air Quality 20.4.2 It is unlikely that any construction, operation or aftercare activities would have a significant impact on ASRs, and so no air quality mitigation measures are recommended at this stage, other that good site practice.
Noise 20.4.3 Noise generated by the construction of the WLES is not expected to cause a significant increase to that generated by the operation of the existing WENT Landfill. There are few NSRs within 300m of the site. 20.4.4 During construction, the topography of the site provides natural acoustic shielding, nevertheless, good site practice is recommended. This would include using only powered mechanical equipment with built-in acoustic shielding and not using percussive piling. Where necessary, temporary noise barriers and/or earth bunds could be constructed. 20.4.5 During operation, it is likely that the most significant noise source would be from landfill- related vehicular traffic on the internal haul roads, the access road and on Nim Wan Road. Minor sources would be from on-site plant such as leachate treatment works, pumps, generators and the flare. To mitigate the most significant sources, the location of fixed plant should be carefully reviewed and permanent noise barriers could possibly be placed alongside roads where necessary.
Water Quality WENT Leachate Management 20.4.6 The leachate treatment facility at the WENT Landfill originally covered approximately 1ha. However, this area has recently been extended by the construction of additional storage lagoons of approximately 2ha in area. 20.4.7 The estimated mean daily leachate production rate for the WENT B Landfill Extension is approximately 500cum/day. During the wet season, the peak monthly leachate generation is calculated at approximately 36,000cum, equivalent to 1,200cum/day averaged over the month. It is assumed that leachate treatment would be similar to that at the existing WENT Landfill, namely treatment followed by pumping to Lung Kwu Sheung Tan and discharge into the North West New Territories Trunk Sewer and outfall into marine waters at Urmston Road offshore from Castle Peak. 20.4.8 If the existing leachate treatment facilities were used for WENT B Landfill Extension, there would be a requirement to construct an additional lagoon to replace the one currently used, which lies within the perimeter of the existing WENT Landfill. As with the existing WENT Landfill, this lagoon could be situated within the WENT B Landfill Extension perimeter, in an area where filling would not take place until late in the life of the landfill.
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20.4.9 If completely separate leachate treatment facilities were constructed, the most feasible site for these would be on the CLP lagoon area. The WENT B extension extends onto the CLP ash lagoons, but leaves an area of approximately 20ha free to accommodate possible bulk waste reduction facilities currently in the planning stages. The area of these facilities is not currently known, but it is considered that the 20ha area allocated is likely to be more than adequate for the likely scale of such facilities. It is therefore likely that a space of up to 4ha could be made available on the CLP lagoons for a leachate treatment facility. Alternatively, the perimeter of the WENT B Landfill Extension could be adjusted to allow sufficient extra space on the CLP lagoons for leachate treatment facilities. 20.4.10 Construction of the WENT B Landfill Extension would entail the diversion of the existing Nim Wan Road and the existing leachate pumping main, although this may occur some considerable time after the initial phases of the WENT B Landfill Extension have become operational. When diversion of the road does occur, it would be feasible to include a rising main of suitable capacity along the new road alignment to a suitable discharge point. 20.4.11 The existing WENT Landfill pumps treated leachate south, along the alignment of Nim Wan Road, to a pumping station from where it is pumped out to sea via a long sea outfall. There are currently 4 pumps (2 of which are stand-by pumps). With two pumps working, the overall pumping capacity is 140 litre/s at 110m head, equivalent to a capacity of approximately 8,000cum/day over a 16-hour operating cycle. The maximum permitted discharge rate is 1,800cum/day. Typical mean pumping rates for the period August 2000 to March 2001 were in the range 700 to 1,600cum/day. The existing pumps are therefore capable of dealing with the quantity of leachate that would be produced by both the existing WENT Landfill and the WENT Landfill Extensions. 20.4.12 The existing pipeline from the WENT Landfill to Lung Kwu Sheung Tan is planned for replacement in 2003. The replacement pipeline would be pressure rated at PN20 in the pumping main section. The existing landfill contractor has carried out a surge analyses for this pipeline with an assumed velocity of 193L/s, and has concluded that the maximum pressures are well below the 20bar rating. A flow rate of 193L/s over a twelve-hour period is equivalent to over 8,000cum/day (the current consented limit is 1,800cum/day). This suggests that the pipeline is capable of dealing with both the existing leachate from the WENT Landfill and a similar additional volume from the WLES. More detailed analyses would be required at a later stage to confirm these preliminary calculations. 20.4.13 Leachate from the existing WENT Landfill is subject to pretreatment (consisting of ammonia stripping and SBR treatment), prior to discharge via the NWNT long sea outfall to Urmston Road. The discharge point lies within the North Western Water Control Zone rather than Deep Bay, and hence impacts on the sensitive Deep Bay area are expected to be minimised. The quality of treated leachate that is should be in accordance with the WPCO Technical Memorandum. The upper concentration limits for discharges to Coastal Waters of the North Western Water Control Zone is 50mg/L total nitrogen, and 300mg/L COD, for discharges of between 1,000 and 1,500cum/day. 20.4.14 The WENT A Landfill Extension occupies a valley to the west of the existing WENT Landfill, and the toe bund of the extension terminates directly to the south of the existing leachate treatment facilities. Given that the overall capacity of the proposed WENT A Landfill Extension is approximately 6Mcum (compared to the total capacity of the existing WENT Landfill of approximately 55Mcum), the provision of separate leachate treatment facilities is likely to be relatively costly over the relatively short operating period. If however this provision was deemed essential, there is considerable flat land for development available on the site of the CLP ash lagoons, adjacent to WENT A Landfill Extension. WENT Sewerage 20.4.15 The existing WENT Landfill and the WLES fall within the Deep Bay Catchment Area. Since the pollution loading of the Deep Bay and its catchment areas have well exceeded its assimilative capacity, any new facilities or development have to demonstrate that they do not impose an additional pollution loading onto Deep Bay.
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20.4.16 In the vicinity of the existing landfill and the extension site, there is no sewage infrastructure development. Therefore all new developments are required to provide on-site sewage treatment facilities. 20.4.17 The amounts of sewage generated will be very small in comparison with quantities of leachate. It is proposed that sewage from the WLES would be disposed of by being fed into the SBR treatment facilities of the leachate treatment plant, and then disposed of to the outfall in Urmston Road together with the treated leachate. The net increase in sewage arising is expected to be minimal in comparison with daily leachate generation, and is not expected to give rise to a measurable increase in pollutant loading. WENT Surface Water Drainage 20.4.18 During construction of the landfill bowl for the WLES, surface water drainage would be shed to the northern perimeter bund via drains cut into the perimeter haul roads to the west and utilising the existing WENT Landfill perimeter drainage to the east. The gradients of these drains would be 1(V) on 4(H); therefore intermediate and final flow attenuation measures would be required. 20.4.19 Following restoration, storm water runoff would flow from the landfill surface and be collected in perimeter drainage. The perimeter drainage would in turn discharge in the west into the main drainage line along the proposed Nim Wan Road diversion; and in the east into the drainage channels flowing through the existing WENT Landfill. To prevent ponding two areas require infilling along the original Nim Wan Road cutting to the west and within the valley situated at the uppermost levels to the east. A minor cut is required to allow flow from this valley to the east. 20.4.20 All water that has passed through areas containing waste should be classed as leachate, and will therefore be treated and discharged as described above. Storm water run-off generated during construction and operation of the WLES is not classed as leachate, but may contain elevated concentrations of suspended solids, as well as oils and other contaminants from road surfaces. Treatment of run-off water may be carried out using settlement tanks to remove suspended solids, and oil interceptors to remove oil and grease. The quality of the discharge would be regulated by means of a Discharge Consent issued in accordance with the WPCO. Standards for discharge into coastal waters of Deep Bay are 25-50mg/L of suspended solids and 10-20mg/L of oil and grease, depending on the volume of water discharged. 20.4.21 It should be noted that many of the existing slopes in the vicinity of the WLES are unvegetated and heavily eroded, and may therefore give rise to considerable concentrations of suspended solids in run-off water under current conditions. Following appropriate treatment, it is envisaged that the concentrations of contaminants in stormwater would be sufficiently low to have no significant impact upon Deep Bay, and would be similar in quality to the existing run-off from the roads and partially vegetated slopes under current conditions.
Waste Management 20.4.22 No specific waste management mitigation measures are recommended at this stage, other that good site practice as described in Part A (Section 5).
Ecology 20.4.23 As vegetation clearance would be necessary for development of the WLES, revegetation works should be undertaken at suitable locations and using suitable native species. The exact location of revegetation activities and the species to be used shall be determined at the detailed EIA Study stage of the project after detailed vegetation survey and habitat mapping has been conducted. The revegetation works should adopt a “landscape ecology” approach in that planting proposals should be co-developed by competent landscape architect with support from a botanist / vegetation ecologist.
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Fisheries 20.4.24 As the site totally land based, there will be no impacts to marine fisheries. Furthermore, there is no (freshwater) fish-farming in the area that would be disturbed by the WLES.
Cultural Heritage 20.4.25 Opportunities to revise the boundary of the WLES to avoid the TTAS were investigated, but are not considered likely to be practicable. A number of options to minimise the impacts on the TTAS, have been considered these are discussed and described in Appendix II and include:
• Preservation Insitu by Burial Beneath the Landfill: This approach leaves the affected relics where they are, but assumes they could be exhumed later if desired. However this option is constrained due the fact that the relics are just below ground-level and are vulnerable to damage from construction of the landfill. Any later exhumation, would also damage the integrity of the landfill, and could result in uncontrolled release of leachate through the base liner. • Preservation by Removal: This approach includes preparation of an archaeological record of the site prior to commencement of the landfill construction. The end result of the programme would be publications that reflect the significance of the data collected, and the creation of a display, either at an existing museum, or at a dedicated facility / visitor centre. This option is the most feasible and practicable approach and has the advantage that it would allow the development of the WLES to continue and at the same time the archaeological relics and findings from the programme could be displayed at a suitable location within the HKSAR as an educational facility that would benefit the community. However, it is also the least preferred as it would result in the loss of some relics as well as a portion of the TTAS for future investigations.
20.4.26 As part of an EIA, a suitable plan for rescue excavation should be drawn up for approval by AMO. All excavation works should be completed (to the satisfaction of AMO) prior to commencement of any construction works. All artefacts should be recorded and photographed during excavation. The arrangements for ensuring the long-term management of the archaeological features is subject to agreement between the project proponent and EPD. However, all artefacts should be displayed in a location and manner which promotes community understanding and knowledge of Hong Kong’s archaeology and cultural heritage. 20.4.27 The study concluded by Field Archaeology Consultants noted that as the two archaeological surveys in Nim Wan area were quite conclusive, no further archaeological survey is considered necessary within the study area covered by those surveys.
Landscape & Visual 20.4.28 It is envisioned that the restored site would blend in with the restoration of the original WENT Landfill, and that both should blend in with the surrounding natural landscape. If the restored landfill is to be made available for low-intensity recreational use, hiking trails and panoramic lookout points with viewing pavilions could be provided.
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20.5 Summary 20.5.1 A summary of the SEA for the WLES is provided in Tables 20.1 and 20.2:
Table 20.1: WENT Landfill Extension SEA
Impacts Score Commentary
Air Quality Assessment
1 Distance to areas of air sensitive O The WLES is situated between the existing WENT Landfill land use and Black Point Power Station. Black Point Power Station is considered as an ASR and it is within 500m from this site. A temple near Tsang Tsui is another ASR. Other ASRs located outside 500m from the site and the associated new access road include the village of Ha Pak Nai which is situated over 1km to the north east, Pak Long and Nam Long which are over 1.8km to the south. 2 Presence of topographic O Major Urban areas such as Tuen Mun and Yuen Long are features which could decrease separated from the WLES by hills, which would assist in or exacerbate impacts minimising air quality impacts. The fact that the WLES is within the Deep Bay air shed may compound impacts upon Ha Pak Nai (1km to the north east) and Pak Long and Nam Long (over 1.8km to the south), however their distance from the site would mean impacts are not significant. It is unlikely that dust or odours would accumulate around the WLES. 3 Occurrence of meteorological O Prevailing winds are from the south-west. The conditions which could predominant wind direction would blow towards exacerbate impacts Shenzhen. However the remoteness of ASRs is such that this criterion is not significant. 4 Cumulative impacts of relevant - Relevant emissions are present within 5km. Sources of emissions (TSP (construction), emissions in the vicinity are the existing WENT Landfill, Nox, CO, SO2 – LFG Flare) Black Point Power Station and proposed waste taking into account ambient management facilities (eg. WEF in Ha Pak Nai) that are conditions currently in the planning stage. There is little road traffic in the area, and so emissions from traffic are likely to be low. 5 Total Emissions of Air Pollutants - The site can utilise both road and marine access. from the territory-wide waste transportation between the RTSs and the site 6 Overall impact - Overall it is considered that the WLES would have a minimal / low air quality impact on surrounding ASRs due to its remote siting. Levels of TSP, NOx, CO, SO2 etc. arising from the landfill are unlikely to exceed AQOs at surrounding ASRs. With good site practice it is highly unlikely that emissions from the WLES would cause any air quality exceedences during construction or operation, although cumulative impacts need to be carefully considered should this option progress to the Detailed Stage. Therefore a ‘Negative – Low’ impact overall.
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Impacts Score Commentary
Noise Assessment
1 Distance to areas of noise O The WLES is situated between the existing WENT sensitive land use Landfill and Black Point Power Station. There are no villages or major urban areas within 300m. The village of Ha Pak Nai is situated over 1km to the north east. Pak Long and Nam Long are over 1.8km to the south. 2 Topographic features O As the WLES is separated from the major urban areas (Tuen Mun) by hills, noise impacts upon them would be (only applicable if there are negligible. Ha Pak Nai is more exposed, however, it NSRs within 300m) would be separated from the WLES by the existing landfill which would prevent line of sight. Impacts would thus be within acceptable levels. 3 Cumulative impacts of O There are no known developments (existing or planned) developments within 300m within 300m of the site. This site is remote from NSRs and there are no surrounding developments which could cause cumulative impacts. 4 Overall Impact O Overall it is considered that the WLES will have minimal noise impacts on surrounding NSRs due to its remote siting. Therefore a ‘Neutral’ impact overall.
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Impacts Score Commentary
Water Quality Assessment
1 Watercourse diversion O No watercourses diversions are likely to be necessary during the works, although a small valley would be lost. Thus there are no significant watercourse issues although drainage issues would need to be addressed. 2 Potential for sediment O Part of the WENT B Landfill Extension would be contaminant release constructed over the PFA Lagoons situated north-east of Black Point Power Station. Whilst some contamination may be present, it should be relatively straight forward to mitigate impacts with sensitive environmental engineering. A phased contaminated land assessment should be undertaken during subsequent, more detailed studies. 3 Potential impacts on WSRs - The site is adjacent to the Deep Bay WCZ which has a zero discharge policy due to its ecological importance. (including increase or Therefore no discharges can be made to Deep Bay that exceedance of WQOs) would adversely affect water quality or WSRs. 4 Potential impacts on O Groundwater may be present as perched water tables groundwater above rockhead and in fissures within the underlying rock mass. However, within the vicinity of the site it is believed that, in common with most of Hong Kong, groundwater is not utilised as a resource. Impacts on background groundwater quality would be minimised by design of a suitable impermeable liner for the landfill, that would prevent discharge of significant quantities of contaminants into groundwater beneath the site. 5 Potential cumulative impacts - There are a number of planned projects adjacent to the (potential for concurrent projects WLES and each of these would likely discharge effluent, to exacerbate preceding to the detriment of the receiving waters. impacts) 6 Overall impact O The site is adjacent to Deep Bay and whilst there is potential for runoff to enter Deep Bay, it is considered that the site and technology are sufficiently well known to be able to control impacts to acceptable levels. Knowledge gained from the construction and operation of the existing WENT Landfill would be invaluable in planning for drainage and leachate management for the proposed extensions. Therefore a ‘Neutral’ impact overall.
Waste Management Assessment
1 Balance of materials O The WLES has been designed to have a balance of cut and fill. (surplus / deficit of public fill needed for landfill development) 2 GHG emissions from mode of - The site has a marine frontage, and is close to the transport for delivery of waste to marine reception facilities at existing WENT landfill. the site from RTSs Waste transportation would be primarily by sea and road. 3 Overall impact O / - With a material balance and waste transportation by sea and road, overall the strategic waste issues associated with the WLES are considered to be ‘Neutral / Negative- Low’.
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Impacts Score Commentary
Ecological Assessment
1 Potential for secondary O There are no protected areas within 500m of the WLES. environmental impacts on “Areas The nearest Protected Areas are the Sha Chau and Lung of Absolute Exclusion” Kwu Chau Marine Park (over 4km to the south west) and an SSSI at Sheung Pak Nai (3.5km to the north east). 2 Affects an important habitat - The majority of this site is grassland / man made lagoons of low or no ecological value. However, there are a few small areas of mixed shrub-land and approximately 4,000m2 of immature native woodland that are of conservation value. Tsang Kok stream would also be lost. 3 Affects a species of conservation - The EIA Report for the existing WENT Landfill refers to a importance population of the Pitcher Plant Nepenthes mirabilis that was found in the valley of the Tsang Kok stream, the site of WENT A Landfill Extension. Although the species is protected, it is reported as being locally abundant in Hong Kong. Further investigation would be required as part of the detailed EIA for the project. 4 Potential for cumulative O / - This area is already disturbed by the existing landfill. ecological impacts on sites of However the potential for cumulative impacts also exists recognised value with planned projects such as WEF. 5 Overall impact - Although there are no Protected Areas within 500m, the WLES would adversely affect an important habitat and a species of conversation importance, albeit ones that are located elsewhere. Nevertheless, together with the likely cumulative impacts from proposed adjacent developments, the overall impact has been assessed as ‘Negative – Low’.
Fisheries Assessment
1 Potential for secondary O Land based site – no impact anticipated. environmental impacts on “Areas
of Absolute Exclusion” 2 Affects an important mariculture/ O Land based site – no impact anticipated. fisheries resources (including
spawning / nursery ground) 3 Potential for cumulative fisheries O Land based site – no impact anticipated. impacts on sites of recognised
value 4 Overall impact O This is a land based site and so there will be no fisheries impacts, i.e., ‘Neutral’.
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Impacts Score Commentary
Cultural Heritage Assessment
1 Important cultural (Declared, - - The WENT B Landfill Extension would cover the existing Deemed or Graded sites) / boundary of the Tsang Tsui Archaeological Site (TTAS), archaeological sites a recorded item under the Antiquities and Monuments Office. Recent excavations in this area have revealed extensive remains of the late Neolithic period (c 2500- 1500 BC). There is also a large grave of the Tang Clan, dating to the late Qing period (c. 100 years old). There are no other declared, deemed or graded sites in the vicinity. 2 Potential for archaeological - Surveys have revealed that TTAS has a high cultural value heritage/ archaeological value. 3 Potential for cumulative heritage O There are no known developments in the vicinity that are Impacts on sites of recognised expected to impact on TTAS. value 4 Overall impact - - Construction of WENT B Landfill Extension could lead to the loss of an important archaeological site, albeit one with no above-ground features of cultural or historic significance. It would also lead to the loss of a large Tang Clan grave. Therefore, the overall impact has been assessed as ‘Negative – High’.
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Impacts Score Commentary
Landscape and Visual Impact Assessment
1 Implications for landscape - Under the Territorial Development Strategy Review planning and designations (TDSR) 1995 Landscape Strategy, the northern part of the site is zoned “Development Area High Landscape Value”, areas of “suburban character with areas of scenic quality”. The WLES will not be consistent with the landscape planning intention for the southern part of the area. Development is not inconsistent with the landscape planning intention for the northern part of the area. 2 Landscape resources - Landscape resources on the site are not very sensitive, there is extensive disturbance already caused by industrial development and landslides, and the magnitude of the potential impacts is (relatively) limited. 3 Landscape character - The effect of the WLES will be to introduce a new landscape feature into an upland area, which is already characterised by an existing landfill and by incongruous power station developments. This will result in impacts on landscape character. 4 Visual - Only limited numbers of VSRs fall within the visual envelope of the WLES. The most significantly impacted VSRs include users of the Nim Wan Road, residents in Lung Kwu Sheung Tan and hikers on the Castle Peak peninsula. Generally however, visual impacts are offset by the indifferent visual quality of this area of the coast and in particular the presence of the existing WENT Landfill, Black Point Power Station and ash lagoons. 5 Overall Impact - Overall, landscape and visual impacts will be ‘Negative – Low’, for the following reasons: • The extension is not compatible with existing landscape planning intentions for the area. • Landscape resources on the site are not of particular sensitivity. • Landscape character is of medium/slight sensitivity, and is already degraded by the presence of the existing landfill, power station and ash lagoons. • VSRs are very few in number, often distant from the WLES and often transient. • The site will eventually be restored to simulate natural landforms and will be given landscape context by existing uplands.
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Impacts Score Commentary
Landfill Gas Assessment
1 Distance between the new / O Other than buildings associated with the existing landfill, extended landfill and SRs the nearest sensitive receivers are >250m away. 2 Number of receivers within 250m O Other than buildings associated with the existing landfill, (i.e. Consultation Zone) the nearest sensitive receivers are >250m away. 3 Man-made / natural pathways for - There are utility routes in the vicinity of the site, LFG migration consisting of the services leading to the existing landfill. However, the pathways via these services to sensitive receivers are long and indirect. There are not considered to be any significant geological pathways from the landfill. 4 Additional utilisation of LFG to O There are no potential off-site users of LFG at this time. reduce GHG emissions 5 Overall impact O There are no particular issue regarding LFG and so the impact is considered to be ‘Neutral’.
Table 20.2: Summary of WENT Landfill Extension SEA
Overall Impacts Score Commentary
Overall Air Quality - Negative – Low Overall Noise O Neutral Overall Water Quality O Neutral Overall Waste Management O / - Neutral / Negative – Low Overall Ecology - Negative – Low Overall Fisheries O Neutral Overall Cultural Heritage - - Negative – High Overall Landscape & Visual - Negative – Low Overall Landfill Gas O Neutral
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Table 20.3 Assessment of Significance of Visual Impacts for WENT Landfill Extension During Construction / Operation Phase (Note: All impacts adverse unless otherwise noted)
VSR Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Construction (Low, Medium, High) before Mitigation Residual Impacts VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR15 Lung Kwu Sheung Tan 1km Very Few Negligible High Insubstantial Insubstantial VR6 Ha Pak Nai 2km Very Few Small High Moderate Slight VR5 Sheung Pak Nai/ Ngau 5km approx Very Few Negligible High Insubstantial Insubstantial Hom Sha VR2 Lau Fau Shan Coast 6km-10km Few Negligible High Insubstantial Insubstantial VR7 Shenzhen (Shekou) 7km Many Negligible High Insubstantial Insubstantial
Occupational Receivers VR16 Workers in Black Point 400m Very Few Intermediate Low Slight to Moderate Slight Power Station VR17 Workers in fields around 1km Very Few Intermediate Low Slight to Moderate Slight Lung Kwu Sheung Tan VR18 Workers in fields around 200m-3.5km Very Few Small Low Slight Insubstantial Ha Pak Nai VR14 Vessels in Deep Bay 500m+ Very Few Intermediate Low Moderate Slight VR19 Workers in Shenzhen 7km approx Many Negligible Low Insubstantial Insubstantial (Shekou)
Recreational Receivers VR10 Hikers on Castle Peak 50m-5km Very Few Small Medium Moderate to Slight Slight Peninsula VR20 Hikers on Lantau 16km Very Few Negligible Medium Insubstantial Insubstantial
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VSR Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Construction (Low, Medium, High) before Mitigation Residual Impacts VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Travelling Receivers VR12 Nim Wan Road 50m Few Large Medium Substantial Moderate VR13 Users of Proposed 6km Moderate Small Medium Moderate to Slight Slight Shenzhen Western Corridor VR14 Vessels in Deep Bay 500m+ Very Few Small Medium Moderate Slight
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual receivers shown in Figure 20.5.
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Table 20.4 Assessment of Significance of Visual Impacts for WENT Landfill Extension During Afteruse Phase (Year 10 after Restoration) (Note: All impacts adverse unless otherwise noted)
Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Afteruse (Low, Medium, High) before Mitigation Residual Impacts
VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Residential Receivers VR15 Lung Kwu Sheung Tan 1km Very Few Intermediate High Moderate Slight VR6 Ha Pak Nai 2km Very Few Small High Slight Insubstantial VR5 Sheung Pak Nai/ Ngau 5km approx Very Few Negligible High Insubstantial Insubstantial Hom Sha
VR2 Lau Fau Shan Coast 6km-10km Few Negligible High Insubstantial Insubstantial
VR7 Shenzhen (Shekou) 7km Many Negligible High Insubstantial Insubstantial
Occupational Receivers VR16 Workers in Black Point 400m Very Few Intermediate Low Slight to Moderate Slight Power Station VR17 Workers in fields around 1km Very Few Intermediate Low Slight to Moderate Insubstantial Lung Kwu Sheung Tan VR18 Workers in fields around 200m-3.5km Very Few Small Low Insubstantial Insubstantial Ha Pak Nai VR14 Vessels in Deep Bay 500m+ Very Few Intermediate Low Slight Slight VR19 Workers in Shenzhen 7km approx Many Negligible Low Insubstantial Insubstantial (Shekou)
Recreational Receivers VR10 Hikers on Castle Peak 50m-5km Very Few Small Medium Moderate to Slight Slight Peninsula VR20 Hikers on Lantau 16km Very Few Negligible Medium Insubstantial Insubstantial
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Key Visually Sensitive Approx. Minimum Nos. of Receivers Magnitude of Impact Receptor Sensitivity Impact Significance Significance of Receiver (VSR) Distance Between (order of magnitude During Afteruse (Low, Medium, High) before Mitigation Residual Impacts
VSR and Source(s) only) (Negligible, Small, (Insubstantial, Slight, (Insubstantial, Slight, Intermediate, Large) Moderate, Moderate, Substantial) Substantial)
Travelling Receivers VR12 Nim Wan Road 50m Few Intermediate Medium Moderate Slight VR13 Users of Proposed 6km Moderate Small Medium Slight Insubstantial Shenzhen Western Corridor VR14 Vessels in Deep Bay 500m+ Very Few Small Medium Slight Slight
Notes: Assessment of Impacts does not account for possible off-site visual mitigation, which may have the effect of reducing certain impacts further. Locations of most important visual receivers shown in Figure 20.5.
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21. CONCLUSIONS AND RECOMMENDATIONS 21.1 Introduction 21.1.1 This Chapter presents a discussion of the findings of the site specific evaluations presented in Chapters 6 to 20 and identifies those sites that are likely to be considered acceptable if investigated further in an EIA. Table 21.1 provides a comparative summary of these evaluations. 21.1.2 All the sites considered in this assessment have been chosen through a site selection exercise, which contributes to the entire SEA process. The site selection process identified a number of environmentally sensitive receivers, where it was considered that development of a new landfill or landfill extension would not be acceptable under any circumstances, (“Areas of Absolute Exclusion”). Locations that were considered likely to be acceptable for development were also identified. This long-list of sites corresponds to the thirteen new sites and two extension sites assessed in this report. 21.1.3 Whilst the site selection exercise allowed the identification of areas of Hong Kong that are suitable in principle for development, the exercise did not take into account the specific environmental impacts associated with landfill development, or the sensitivity of adjacent sensitive receivers to those impacts. The purpose of this SEA is to qualitatively assess the specific environmental impacts of landfill development at each of the sites, taking those factors in to account. 21.2 Approach to the Strategic Environmental Assessment Design Issues 21.2.1 At this stage in the project a number of issues have yet to be determined, precluding detailed quantitative environmental assessment of impacts. One of the benefits of addressing environmental impacts at this early stage of the overall process is that it allows a greater flexibility in design. Hong Kong has designed and implemented some of the most sophisticated landfill environmental control technology in the world. This has been successfully applied to the existing strategic landfills and in the restoration of old landfills. On the basis of Hong Kong’s proven knowledge of the efficacy of existing control technologies, as well as an acknowledgement of the need to keep abreast of future developments, it is assumed in this SEA that certain environmental emissions (for example, effluent discharges and landfill gas flare emissions during landfill operations) can be effectively mitigated through design. 21.2.2 In order to reduce the overall impacts on water quality during construction of marine based sites, the design approach for the formation of the island sites has been to eliminate the need for dredging of underlying muds during the reclamation process. 21.2.3 In terms of wind and waves, whilst this “no-dredge” technique is considered suitable for “protected” seawalls, the ability of this approach to provide adequate stability for “exposed” seawalls is subject to verification. Some of the sites (particularly those in southern and eastern waters) will be exposed to considerable wave action and may require a dredged foundation trench to ensure adequate stability. For the purposes of this SEA and the water quality modelling exercise, a “worst case” approach has been adopted which includes for dredging of the foundation trench of exposed seawalls at sites in eastern and southern waters. However, the viability of the no-dredge option for all seawalls should be confirmed in subsequent stages of the design.
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Table 21.1: Comparative Summary of Evaluations
Overall Impacts
Site Air Quality Noise Water Quality Waste Management Ecology Fisheries Cultural Heritage Landscape & Visual Landfill Gas
M.1 Deep Bay Island Landfill O / - O - - O - - - / - - - - - O
M.2 Sha Chau Island Landfill O / - O - O - / ------O
M.3 Lantau Northwest Island Landfill O / - O / - - O - - - - - / - - O
M.4 Soko Islands Landfill O / - O - O - / - - - / - - - - / - - O
M.5 South Cheung Chau Island Landfill O O O / - + O / - O / - O - / - - O
M.6 Lamma Breakwater Island Landfill O O - + - / - - - - - / - - O
M.7 East Tung Lung Island Landfill O / - O - O ------O
M.8 Eastern Waters Island Landfill O / - O O / - O - / - - - O - O
M.9 Tai Long Wan Offshore Island Landfill O / - O - O - / - - O / - O - O
M.10 Southeast Offshore Island Landfill O / - O O / - O O / - O / - O - O
M.11 Lamma North Island Landfill - O / - - + - / ------O / +
M.12 Lamma South Island Landfill O O - + - - - - - / - - O
L.1 Pillar Point Valley North Landfill - O O - - O O - O
E.1 NENT Landfill Extension - O / - O - - O - - - O
E.2&3 WENT Landfill Extensions - O O O / - - O - - - O
Notes: “+ +” Positive – High “+” Positive “O” Neutral “O / -” Neutral / Negative – Low “-” Negative – Low “- / - -” Negative – Low/ High “- -” Negative – High
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Selection and Application of Evaluation Criteria 21.2.4 The evaluation criteria for each environmental discipline are described in Part A – Section 5. Because the assessment is qualitative in nature, the evaluation criteria have been developed to ensure an assessment of sites that is transparent and consistent. To allow for future assessment of a preferred site under the EIAO-TM, evaluation criteria and individual thresholds have been developed based on the EIAO assessment criteria, but adapted on the basis of professional judgement where considered appropriate for a strategic environmental assessment. Modification has also been necessary to accommodate the different types of impact associated with land based development and marine development. 21.3 Brief Comparison of Environmental Impacts Associated with Land Based Sites and Marine Sites General 21.3.1 As might be expected, the nature of impacts associated with land and marine based sites are quite different. A feature of the design approach to this Study has been to alleviate the burgeoning problem of managing a projected surplus of inert C&D material. At certain times, in the absence of identified public filling sites, C&D Material has been disposed of at the existing strategic landfills. This prematurely reduces landfill void space and lifespan. Because all marine sites can accept significant volumes of public fill for site formation, these sites provide enormous strategic benefits, both in the management of the supply of landfill space and the disposal of C&D material. This “strategic” factor contributes to the overall pursuit of sustainability for Hong Kong, but could result in adverse project-level impacts. Therefore it has not specifically been included in the assessment process, however, it may be taken into account when selecting a preferred site(s) from those ultimately identified in the site selection exercise.
Marine based Sites vs Land based Sites 21.3.2 By their nature, the principal impacts associated with marine based sites are those impacts upon water quality, and perhaps more importantly, the related impacts to marine ecology and fisheries. The impacts themselves are more complex and diverse than for land based sites. This is due to the media through which impacts arise and are transmitted as well as the relatively better understanding of the baseline situation and effects of development upon land based sensitive receivers. 21.3.3 The hydrodynamic effects and resulting water quality impacts will vary across Hong Kong waters according to the existing and future predicted conditions. The geographical range over which marine based site formation can impact upon sensitive receivers is considerably greater than for land based sites, with significant variation depending upon the exact position of the site in Hong Kong waters. Water quality and associated impacts for marine sites have been assessed on the basis of a hydrodynamic and water quality modelling exercise carried out separately under this study. The assessment presented in this Report has taken into account the results of that modelling exercise. 21.3.4 Conversely, land based sites are characterised by the relatively localised effects of impacts. Whilst the actual degree of severity of any particular impact is dependent upon the nature of the sensitive receiver, land based sites tend to have greater opportunity for mitigation of impacts.
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21.4 Discussion of Impacts 21.4.1 The following sections present a discussion of the predicted impacts upon each environmental discipline, as summed up in Table 21.1. Recognising that the SEA has been carried out in a qualitative manner, the following sub-sections identify sites which, if investigated further, are unlikely to comply with the EIAO-TM, (for that particular media), as well as those which are considered suitable for further investigation. This evaluation of “compliance ” should be taken in the context of this SEA, and it should be recognised that the actual design of new sites and extensions is preliminary in nature and an EIA under the EIAO will be necessary for those sites selected for further investigation. 21.4.2 The evaluation of likely acceptability of impacts has been based on a combination of qualitative judgement and quantitative assessment. Whilst the assessment process presented in Table 21.1 uses a simple scoring technique for clarity, the final evaluation is also based upon professional judgement. It is not the intention that the scores in Table 21.1 are compared numerically for each site. Furthermore, one of the purpose of the SEA is to identify those sites that are suitable for further investigation, the weighting of individual criteria has been avoided with each environmental discipline evaluated on its own merit. 21.4.3 Ranking of those sites considered likely to have acceptable environmental impacts has generally been avoided. However, in order to facilitate a clear understanding of the nature of predicted impacts, sites have been divided into broad categories according to the general severity of impacts, which in turn relate to the likely degree of mitigation that may be required. Because the sites have been divided in to broad categories, each categorisation does not necessarily correspond directly to the scores presented in Table 21.1.
Air / Noise / Landfill Gas 21.4.4 Impacts upon air quality, noise and landfill gas are considered to be acceptable for all sites. 21.4.5 For marine based sites this is predominantly due to the site selection exercise, which ensured that new sites are located well away from land based sensitive receivers. The influence of noise upon ecological sensitive receivers has been addressed under that section. 21.4.6 The effects of air/noise/landfill gas impacts upon construction workers, (for landfill gas) and afterusers, (for noise, air and landfill gas) is recognised – but can be readily mitigated through design. However the mitigation measures and their acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. 21.4.7 For land based extension sites, there is a potential for impacts, however, this is still limited. The process of site search and selection that was carried out for the existing NENT and WENT Landfills ensured that these are located in remote areas. Therefore, the proposed extensions are also located in remote areas where the effects upon sensitive receivers are likely to be limited. 21.4.8 Whilst landfill gas can be used as an energy source to support on-site activities at all sites, at this time there are no readily identifiable off-site users, to further offset greenhouse gas emissions.
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Water Quality 21.4.9 The following sub-sections present a brief discussion of the key water quality impacts of each site. The water quality evaluation has been carried out with regard to the results of the water quality and hydrodynamic modelling exercise. Sites with Overall Very Low Water Quality Impacts 21.4.10 The sites considered to have the lowest potential impact upon water quality are:
• Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES); and • WENT Landfill Extensions (WLES).
21.4.11 The land based sites (PPVNL, NLES, WLES) are considered to have relatively low potential impacts. For these sites, impact avoidance can be readily achieved through sensitive design, and where necessary impact mitigation, can be achieved with a reasonably high degree of assurance on the basis of previous experience, both through design and management. 21.4.12 The existing strategic landfills (to which NLES and WLES would be extensions) have provisions in place for disposing of waste water discharges (e.g. an effluent discharge pumping main). Whilst the actual design has yet to be completed, the necessary infrastructure can either accommodate the additional loading or be upgraded to suit as necessary. 21.4.13 For PPVNL, the potential impacts are considered to be low because of the low sensitivity of the surrounding waters, coupled with the proven ability to manage site discharges during construction and operation. 21.4.14 At this strategic and qualitative level of assessment, these sites are considered likely to have acceptable impacts upon water quality. However, their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Low to Medium Water Quality Impacts 21.4.15 The sites considered to have potential to cause negative low to medium level impacts upon water quality are those sites generally located around the southern waters, and include:
• South Cheung Chau Island Landfill (SCCIL); • Lamma Breakwater Island Landfill (LBIL); • Eastern Waters Island Landfill (EWIL); and • Southeast Offshore Island Landfill (SEOIL).
21.4.16 All the sites are characterised by uncontaminated sediments. LBIL and SCCIL have a low potential for cumulative effects from adjacent marine developments. The exception to this is the potential Lamma Breakwater, the location of which coincides with LBIL and which may, if constructed impact on the SCCIL and LBIL, however, the status of this project is uncertain. At EWIL, there is potential for cumulative effects from a number of dredging and backfilling projects in the area.
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21.4.17 The potential for WQO exceedance for SS during construction has been predicted for SCCIL. The presence of an island at any of the sites during operation is not anticipated to contribute to any WQO exceedance. In addition, these sites are influenced to some degree by the Pearl River Estuary and generally have higher baseline levels of WQO criteria pollutants, than the eastern waters. 21.4.18 Although LBIL was categorised as ‘Negative – Low’, the water quality impacts, in fact, can either be at the upper end of ‘Negative – Low’ or at the lower end of ‘Neutral / Negative – Low’. It was finally categorised as ‘Negative – Low’ so that the relative differences in water quality impacts with respect to SCCIL could be illustrated. Therefore, it is more appropriate to assign LBIL as having the low to medium water quality impacts. 21.4.19 Anticipated impacts upon EWIL, are judged to be marginally greater. Whilst the site is situated in oceanic waters, remote from WSRs, there are a number of projects in the general area (such as backfilling of East Tung Lung Chau MBA) that may give rise to cumulative impacts. 21.4.20 SEOIL is very remote, situated in waters heavily influenced by oceanic currents. The potential for impacts upon water quality sensitive receivers is low due to the high dispersion of sediment from dredging, also, due to its remoteness, the site is not likely to significantly impact upon the hydrodynamics of Hong Kong inland waters, however, due to its exposed location, the incidence of high winds and waves is likely to make it difficult to implement mitigation measures (should they be required). 21.4.21 At this strategic and qualitative level of assessment, a number of water quality issues were identified but the potential impacts could be minimised by careful design and planning of the facilities in the design stage. The overall acceptability would be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Medium Water Quality Impacts 21.4.22 The sites considered to have potential to cause medium level impacts upon water quality sensitive receivers include:
• Sha Chau Island Landfill (SCIL); • Lantau Northwest Island Landfill (LNWIL); • Soko Islands Landfill (SIL); • East Tung Lung Island Landfill (ETLIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); • Lamma North Island Landfill (LNIL); and • Lamma South Island Landfill (LSIL).
21.4.23 TLWOIL, LNWIL, SIL and LNIL are characterised by uncontaminated sediments and are generally either within the anticipated hydrodynamic influence of a number of WSRs or are in an area where there is the potential for cumulative impacts from adjacent marine based developments. 21.4.24 TLWOIL is remote, situated in waters heavily influenced by oceanic currents (similar to EWIL). The likelihood of impacts upon secondary contact recreation sub-zones along the Sai Kung Peninsula (including Tai Long Wan) is considered limited, however impacts could be exacerbated by cumulative impacts from the mud disposal at south of Victor Rock and the East Ninepin Marine Disposal Area.
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21.4.25 SIL, LNIL, LSIL and LNWIL are all situated such that exceedance of WQO for SS is predicted at nearby water quality sensitive receivers during construction. For SIL, the water quality sensitive receiver is the north side of the Soko Islands; for LNIL, it is the north and north-west of Lamma; and for LNWIL, it is Tai O village and its environs. For LSIL, it is the south Ha Mei Wan and the secondary sub-zone located at south Lamma. For LNWIL there is also potential for cumulative impacts arising from further development at Tung Chung, although the likely influence is considered to be limited. 21.4.26 SCIL is located, in part, over the boundary of the East Sha Chau Contaminated Mud Disposal Area. Filling operations may result in release of contaminated sediment. In addition, cooling water intakes at Chek Lap Kok as well as Black Point and Castle Peak Power stations are close to the site and may be adversely impacted. No WQO exceedance is predicted during construction, however, the presence of the island is predicted to cause salinity WQO exceedance, due to the low baseline salinity in the area. 21.4.27 ETLIL is located in the eastern waters that are generally have high background water quality conditions. Nevertheless, according to the Hydrodynamic and Water Quality Modelling there is an exceedance in the baseline condition. The contribution of the island to exceedance during the operational phase was not significant. Also, no exceedance would be caused due to the construction of the island. However, the site is likely to impact on secondary contact recreation areas around Po Toi as well as cooling water intakes at Cape D’Aguilar. The site is in close proximity to the East Ninepin Marine Disposal Area, and cumulative impacts are likely. 21.4.28 Further investigation is required to determine the details of the design and mitigation measures to reduce the potential impacts to an acceptable level. The overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall High Level Water Quality Impacts 21.4.29 The only site considered to have potential to cause overall higher levels of impact upon water quality sensitive receivers,was:
• Deep Bay Island Landfill (DBIL). 21.4.30 DBIL is located in Deep Bay and in an area of contaminated sediments. The site is located close to the landmass of NWNT and impacts upon secondary contact recreation areas along the coastline are likely during construction when significant exceedance of the SS WQO is predicted. These impacts are likely to be exacerbated by the construction of the proposed SWC. During operational phase, the flushing capability of Deep Bay is predicted to be reduced. This is likely to make Deep Bay more vulnerable to deterioration of water quality due to increase in pollutant loading inside Deep Bay.
Waste Management 21.4.31 The following sections present a brief discussion of the predicted strategic-level impacts associated with waste management. Impacts associated with each site are considered in terms of materials balance, as well as relative greenhouse gas emissions associated with transportation of waste to the individual sites both in terms of distance and mode of transport.
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Sites with Overall Positive Waste Management Impacts 21.4.32 The sites considered to have an overall positive waste management impact include:
• South Cheung Chau Island Landfill (SCCIL); • Lamma Breakwater Island Landfill (LBIL); • Lamma North Island Landfill (LNIL); and • Lamma South Island Landfill (LSIL).
21.4.33 All of these marine sites are considered to have an overall positive impact on waste management / materials balance. As discussed in Section 21.3, marine sites can accept high volumes of public fill for site formation, providing significant strategic benefits in managing the predicted surplus of C&D materials across Hong Kong. In addition, off-shore sites would accept wastes via marine vessel, thereby rendering secondary environmental benefits of reduced greenhouse gas emissions (compared to land based delivery). Compared to other marine based sites, these sites are comparatively close to the source of waste (less than 300km), and consequently have comparatively lower overall GHG emissions. 21.4.34 All sites are considered likely to have acceptable impacts upon waste management, if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Neutral Waste Management Impacts 21.4.35 The sites considered to have an overall neutral waste management impact include:
• Deep Bay Island Landfill (DBIL); • Sha Chau Island Landfill (SCIL); • Lantau Northwest Island Landfill (LNWIL); • Soko Islands Landfill (SIL); • East Tung Lung Island Landfill (ETLIL); • Eastern Waters Island Landfill (EWIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); and • Southeast Offshore Island Landfill (SEOIL).
21.4.36 These sites benefit from the same characteristics (i.e. off-shore based, with marine delivery of wastes) as the sites identified as having an overall positive impact on waste management above, however they are marginally differentiated by their increased distance from the source of waste. 21.4.37 All sites are considered likely to have acceptable impacts upon waste management, if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Neutral to Negative Low Waste Management Impacts 21.4.38 The sites considered to have an overall neutral to negative low, waste management impact include:
• Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES); and • WENT Landfill Extensions (WLES).
21.4.39 All land based sites are considered to have a neutral or low adverse impact on waste management / materials balance. Whilst they do not provide a sink for surplus C&D material, these sites do achieve a materials balance in terms of cut and fill for landfill development.
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21.4.40 WLES has a marine frontage, so it can accept wastes from both land and sea. Whilst this has operational benefits, the secondary environmental benefits of reduced GHG emissions are not as high as for marine based sites. Similarly these benefits are not achieved for PPVNL and NLES, which would receive wastes exclusively by road (although PPVNL could be designed to accept waste transferred by road from the existing WENT Landfill Marine Waste Reception Area). 21.4.41 All sites are considered likely to have acceptable impacts upon waste management, if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out.
Ecology 21.4.42 Through the efforts of botanists, biologists and ecologists, there is a broad ecological database available for habitats and species across the SAR. For most of the waste disposal site options there have been specific studies conducted in the immediate vicinity of the sites that give good insight as to the conservation value of their existing ecological resources. For other more remote marine sites however, such as SEOIL and TLWOIL, site-specific data and information is scarce. In these cases reasonable assumptions have been made based on available data from adjacent waters. The following sections present a brief discussion of the predicted impacts upon ecology. Sites with Overall Low to Medium Ecological Impacts 21.4.43 The sites considered to have the lowest potential ecological impact include:
• South Cheung Chau Island Landfill (SCCIL); and • Southeast Offshore Island Landfill (SEOIL).
21.4.44 Potential impacts at SCCIL are considered low because the site footprint and adjacent waters do not provide a habitat to any species of note. There have been observations of marine mammals in the area, but these are relatively scarce compared to other waters in the west and the south of the SAR. Other sensitive ecological receivers in south-west waters are remote from the site and given the history of the site as a mud disposal ground there is only marginal potential for adverse ecological impacts. 21.4.45 Although proposed for open waters that are contiguous with ecologically valuable coastal waters, SEOIL is considered too remote to be of significant threat to ecological receivers. The potential for impacts upon water quality sensitive is low due to the high dispersion and dilution of dredged / disturbed sediment. 21.4.46 These sites are considered likely to have marginal impacts upon the ecosystem in their vicinity. Development at these sites is not expected to give rise to any significant ecological impacts. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Medium Ecological Impacts 21.4.47 The sites considered to have moderate potential ecological impact include:
• Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES); and • WENT Landfill Extensions (WLES).
21.4.48 Development of PPVNL would adversely affect an otherwise undisturbed habitat that supports a mosaic of habitat types. There is potential that flora of conservation importance are within the site, whilst fauna may use the site directly or use the adjacent undisturbed areas. As the site is in a valley area with no other activities planned, there is limited potential for cumulative impacts.
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21.4.49 The ecological impacts associated with land based NLES are potentially significant. The site is adjacent to the proposed Country Park at Robin’s Nest and NLES would also be in proximity (about 200m) to the Lin Ma Hang stream that is of high conservation value. The site is in a location which is sensitive, but which is marginally acceptable assuming strict protection of adjacent sensitive receivers (particularly Lin Ma Hang Stream). 21.4.50 WLES would be developed adjacent to the existing WENT Landfill and there is also some flora of conservation value in the area: in this case, a population of the Pitcher Plant Nepenthes mirabilis in the valley of Tsang Kok stream. This species is protected, but is also abundant in Hong Kong and, subject to further investigation at the EIA stage its loss could likely be mitigated. 21.4.51 Overall it is considered that these sites possess some attributes of ecological importance, and that potential impacts upon these could be adequately mitigated. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Medium to High Ecological Impacts 21.4.52 The sites considered to have medium to high potential ecological impact include:
• Sha Chau Island Landfill (SCIL); • Soko Islands Landfill (SIL); • Lamma Breakwater Island Landfill (LBIL); • Eastern Waters Island Landfill (EWIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); and • Lamma North Island Landfill (LNIL);
21.4.53 SCIL is located within an ecologically important fisheries habitat and forms part of the core area for the Chinese White Dolphin Sousa chinensis. Whilst the pelagic groups are adapted to the high background concentrations in suspended solids and also have the ability to avoid areas of disturbance at the island landfill site, ecological impacts from the site works may be significant. 21.4.54 SIL is in proximity to two proposed Marine Parks and habitat for species of conservation value, including corals at the Soko Islands and open water habitat for the Chinese White Dolphin Sousa chinensis. Another species of note in the broader area that may be adversely affected by direct habitat loss and off-site sediment plume includes the Horseshoe Crab. 21.4.55 The proposed South Lamma Marine Park and the Sham Wan SSSI / “Restricted Area” are located 2km and 5km to the east of LBIL respectively. Construction and operational phase water quality and hydrodynamic impacts could adversely affect these waters. The site is also adjacent to the core habitat area of the Finless Porpoise – a locally, regionally and internationally protected species. 21.4.56 EWIL is located in the eastern oceanic waters of the SAR. The inner eastern waters support scattered coral communities of high conservation value and in this regard the waters around the Sai Kung Peninsula are currently being investigated by AFCD to determine their suitability for designation as Marine Park / Reserve1. To the north of EWIL is the submerged pinnacle of Victor Rock that is of recognised conservation value for the high diversity community of hard and soft corals and associated reef species it supports.
1 Hong Kong Institution of Education. Study on the suitability of Tai Long Wan Area as marine park or marine reserve. Hong Kong Institution of Education. Study on the suitability of Long Ke Wan and East High Island Dam, Pak Lap Tsai and Pak Lap as marine park or marine reserve. Hong Kong Institution of Education. Study on the suitability of Bluff Island, North and South Ninepin as marine park or marine reserve.
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21.4.57 In the vicinity of TLWOIL, the Tai Long Wan SSSI and other coastal areas of the Sai Kung East Country Park and coral habitats of conservation value in the area are prone to adverse impact from increased suspended sediment levels from dredging and reclamation activities. The potential for cumulative effects is considered marginal due to the distance and hydrodynamics between the island landfill site and possible reclamation to the south. 21.4.58 The waters near LNIL are of ecological value due to the presence of the coral community at Pak Kok. Water quality modelling predicts that corals would be exposed to a significant increase in suspended solids. The waters to the south are of limited use by the Finless Porpoise, although marine access to the site may lead to increased potential for vessel collision. 21.4.59 The ecological significance of these sites is notable, including proximity to particular habitats and species of high conservation significance. There are also a number of areas in the vicinity of these sites that are of designated conservation importance, either existing or proposed. Mitigating potential impacts upon ecological sensitive receivers from the development of any of the above sites is likely to be very difficult. Proposals to develop any one of the above sites should be subject to very thorough ecological investigation as part of an EIA Study. 21.4.60 From a review of AFCD data for the distribution of the Finless Porpoise, although LBIL is in proximity to the core habitat, it does not appear to be within the core area. It is considered that there is potential to avoid unacceptable adverse impacts upon this species. However, this will be subject to confirmation at the detailed EIA stage. In contrast, AFCD data for the Chinese White Dolphin shows that SCIL is located within the core area of this mammal, as such, relocating SCIL would not significantly reduce the potential for disturbance / vessel collision on this species. 21.4.61 For the remaining four ‘Medium to High Impact’ sites the key issues relate to coral communities that are sedentary and, as such, are unable to avoid sediment-induced impacts. However, in most cases the landfill site location is not immediately adjacent to the coral communities and it is thus considered that there is some opportunity to manage the works in such a manner that impacts (i.e., from sediment release / transportation) may be avoidable or limited to within acceptable levels. It is thus recommended that these sites be subject to detailed investigation at the EIA stage. The exception to this is SIL that has added sensitivity due to proposals to establish a Marine Park / Reserve in coastal waters around the Soko Islands. Sites with Overall High Ecological Impacts 21.4.62 There are a number of sites for which the potential ecological impacts are anticipated to be unacceptably high to the extent that they could not be adequately mitigated. These include:
• Deep Bay Island Landfill (DBIL); • Lantau Northwest Island Landfill (LNWIL); • East Tung Lung Island Landfill (ETLIL); and • Lamma South Island Landfill (LSIL).
21.4.63 Deep Bay has a unique ecological context. The immediate vicinity of DBIL is a habitat of Horseshoe Crab – a restricted species – and is close to the Pak Nai SSSI. The Inner Deep Bay ecosystem is comprised of shallow sub-tidal waters and inter-tidal flats and mangroves that together form one of the most bio diverse ecosystems in the South China region. The potential adverse impacts on Deep Bay from a decline in water quality and hydrodynamic change would not be acceptable.
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21.4.64 The ecological significance of LNWIL is broadly similar to that of Deep Bay in that the immediate footprint area would infringe upon, or be in proximity to, habitat for the Horseshoe Crab. There is also a diverse array of shallow sub-tidal and inter-tidal habitats and species along the adjacent Lantau coastline. Whilst the habitat and species diversity is not as great as DBIL, the deeper coastal and offshore waters are at the edge of the core habitat for the Chinese White Dolphin Sousa chinensis. There is also potential for adverse impacts on water quality from hydrodynamic change and cumulative effects from future works at Tung Chung. 21.4.65 The aquatic environment at ETLIL is quite different from that in the vicinity of DBIL and LNWIL. The waters around ETLIL are only marginally influenced by flow from the Pearl River and so water clarity is far greater. This is conducive to coral growth on island shelves. Accordingly, there are highly valued coral communities and associated species of conservation importance on all sides of the site, including SSSIs of ecological importance. 21.4.66 LSIL would be immediately adjacent to the proposed Lamma South Marine Park, and is approximately 1km south of the Green Turtle Restricted Area at Sham Wan. The area is the most important in the SAR for the Green Turtle and is near to a core habitat for the Finless Porpoise. There are also coral communities of high conservation value on the south-facing Lamma coastline, and so overall the area is of high ecological sensitivity and conservation value.
Fisheries 21.4.67 The following sections present a brief discussion of the predicted impacts on fisheries resources, indicating that impacts upon fisheries are likely to be acceptable at all sites. Sites with Overall Very Low Fisheries Impacts 21.4.68 Sites with neutral or very low potential for fisheries impact are the three land based sites:
• Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES) and • WENT Landfill Extensions (WLES)
21.4.69 The three terrestrial sites are not in proximity to any land based aquaculture activities. Likewise there is no potential for mariculture zone impacts from NLES. There is in theory some potential impact on mariculture and coastal / marine fisheries from the development of PPVNL or WLES as watercourses from both of these sites will ultimately drain into the coastal waters off Castle Peak. These coastal waters are of some fisheries significance. However, water quality control measures can effectively be incorporated into landfill design to ensure there are no construction or operational phase discharges to coastal waters. Sites with Overall Low to Medium Fisheries Impacts 21.4.70 Sites with low to medium potential fisheries impact include:
• South Cheung Chau Island Landfill (SCCIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); and • Southeast Offshore Island Landfill (SEOIL).
21.4.71 SCCIL is located across two moderately productive fishing zones. However, assuming sediment impacts are not exacerbated significantly above existing, impacts are not considered to be insurmountable.
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21.4.72 The remote location of TLWOIL relative to areas of fisheries importance means that the hydrodynamics are not particularly conducive to generate adverse impact. However, as there are sensitive areas to the north-west and the south-east there is slight impact potential. Likewise, the remoteness of SEOIL is such that there is very little potential for adverse fisheries impact. Fisheries resources of note in the broader area are the fisheries spawning area west of the site, and marginal potential for impact upon the Fisheries Protection Area and the artificial reef deployment area at Port Shelter, some 20km to the north-west of SEOIL. The potential for cumulative impacts at these sites is also marginal. 21.4.73 These sites are considered likely to have acceptable impacts related to fisheries if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Medium Fisheries Impacts 21.4.74 The sites considered to have moderate potential fisheries impact are the marine sites:
• Sha Chau Island Landfill (SCIL); • Soko Islands Landfill (SIL); • Lamma Breakwater Island Landfill (LBIL); • Eastern Waters Island Landfill (EWIL); • Lamma North Island Landfill (LNIL); and • Lamma South Island Landfill (LSIL).
21.4.75 The area around SCIL is of importance as a spawning ground for several commercially valuable fish species. However, as the extent of the impact zone from site reclamation activities is not expected to infringe on the core fisheries resource area, impacts should be limited. 21.4.76 The southern waters of Hong Kong have been identified as an important spawning and nursery ground for a range of commercially important fish and crustaceans. This “zone” encompasses the waters around SIL, LBIL and LSIL. However, the area of this productive spawning zone is considerable and the water quality impacts from development activities for these sites are generally not anticipated to be significant. 21.4.77 The fishing zone in the vicinity of EWIL has generally low fisheries productivity in the SAR. Spawning and nursery ground for a range of commercially important fish and crustaceans are found some distance from the site at Port Shelter. Whilst not considered likely to be significant, any reduction in water circulation / quality in inner Port Shelter could result in adverse impacts upon capture fisheries. 21.4.78 The small but productive Po Lo Tsui fisheries zone is closeto LNIL. Any impact on the water column from reclamation works would drive the fish from these coastal waters into other protected waters. Thus the potential impact would be marginal. 21.4.79 These sites are considered likely to have acceptable impacts related to fisheries if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Medium to High Fisheries Impacts 21.4.80 The sites considered to have medium to high potential fisheries impact include:
• Deep Bay Island Landfill (DBIL); • Lantau Northwest Island Landfill (LNWIL); and • East Tung Lung Island Landfill (ETLIL).
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21.4.81 DBIL would be located adjacent to the mariculture sub-zone in Deep Bay where historical oyster farming activities continue today. The short-term economic viability of these activities is questionable, particularly given the proximity of the proposed Shenzhen Western Corridor. However, for DBIL the fisheries impact is considered to be of medium to high significance. 21.4.82 At LNWIL the broader area is of importance as a spawning ground for several commercially valuable fish species, with productive fish spawning areas defined at northeast and south Lantau. The coastal waters near the site, including Outer Tai O, support several fish species of commercial value. There is also some potential for cumulative effects in the area. As the Tai O fishery is still active the potential for adverse fisheries impact at this site is potentially significant. 21.4.83 The immediate ETLIL area is of fisheries significance as a spawning ground, whilst the Port Shelter area to the north is also a nursery ground where fisheries protection measures including designation of a Fisheries Protection Area and artificial reef deployment have been undertaken. Whilst impacts may be significant in the immediate vicinity of the site, it is considered that there is limited potential for adverse impact upon fisheries resources at Port Shelter due to the hydrodynamics of the area. 21.4.84 These sites are considered likely to have acceptable impacts related to fisheries if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out.
Cultural Heritage 21.4.85 The following sections present a brief discussion of the predicted impacts upon cultural heritage. As noted in Section 5.8, a fundamental difference between evaluating impacts upon marine based sites and land based sites, is the greater understanding of the existing archaeological value of land based sites. In this regard, marine based sites have been considered to have potentially adverse cultural heritage impacts where they have a reasonable potential to yield deposits of archaeological interest, by virtue of known land based activities in their vicinity. 21.4.86 For marine based sites, the absence of existing information prevents evaluation of potential impacts in the same manner as for the land based sites, which have been subject to detailed investigation. At this stage no marine sites have been excluded from further investigation. However, it has been requested that any marine based sites that are investigated further should include a marine archaeological investigation as part of future studies. Sites with Overall Low Potential Cultural Heritage Impacts 21.4.87 The sites considered to have an overall low potential to cause impacts upon cultural heritage include:
• South Cheung Chau Island Landfill (SCCIL); • Eastern Waters Island Landfill (EWIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); • Southeast Offshore Island Landfill (SEOIL); and • Pillar Point Valley North Landfill (PPVNL).
21.4.88 None of these sites demonstrate any direct evidence of archaeological potential / impact. This is due to the absence of previous investigations in these areas. 21.4.89 SCCIL is located over disposal / borrow areas and as such has been subject to considerable disturbance, rendering the likelihood of finding or impacting upon any remains of cultural heritage interest remote.
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21.4.90 The sites located in the eastern waters, EWIL, TLWOIL and SEOIL are situated in open waters remote from land based sites of known historical significance. Whilst there remains considerable uncertainty over the potential for marine archaeological finds at these sites, their remote location in open waters limits the possibility of potential impacts, compared to say inland sites, close to recognised land based sites with historical links to maritime activities. 21.4.91 PPVNL is situated within the boundary of the Castle Peak Firing Range (no known surveys have been carried out here due to the limited access). 21.4.92 These sites are considered likely to have acceptable impacts upon cultural heritage if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall Low to Medium Potential Cultural Heritage Impacts 21.4.93 The sites considered to have an overall low to medium potential to cause impacts upon cultural heritage include:
• Deep Bay Island Landfill (DBIL); • Sha Chau Island Landfill (SCIL); • Lantau Northwest Island Landfill (LNWIL); • Soko Islands Landfill (SIL); • Lamma Breakwater Island Landfill (LBIL); • East Tung Lung Island Landfill (ETLIL); • Lamma North Island Landfill (LNIL); and • Lamma South Island Landfill (LSIL).
21.4.94 None of these sites have any direct evidence of archaeological potential / impact. With the exception of LNWIL, this is due to lack of previous investigations in these areas. The marine archaeological investigation previously carried out in the vicinity of LNWIL was confined to the inner bay of Tai O but did not yield any evidence of historical interest. 21.4.95 ETLIL is located over disposal / borrow areas and as such has been subject to considerable disturbance, rendering the likelihood of finding or impacting upon any remains of cultural heritage interest remote. 21.4.96 All marine based sites in this category are those considered to have the potential to yield information of cultural heritage interest and are potentially subject to negative impacts. All sites are located in inland waters either in reasonable proximity to land based sites with a known history of maritime activities and/ or are situated in marine vessel routes used by merchants along the South China Coast. Of this group of sites, due to its slightly exposed location in more open waters, and the history of sand dredging over part of its area, SIL is considered least likely to yield finds of archaeological interest. 21.4.97 Notwithstanding, these sites are considered likely to have acceptable impacts upon cultural heritage if considered further in an EIA. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. Sites with Overall High Potential Cultural Heritage Impacts 21.4.98 The sites considered to have an overall high potential to cause impacts upon cultural heritage include:
• NENT Landfill Extension (NLES) and • WENT Landfill Extensions (WLES).
21.4.99 Both these sites include areas of recognised historical and archaeological significance and have been surveyed by the Antiquities and Monuments Office (AMO).
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21.4.100 NLES is located adjacent to the Tong To Shan Settlement (TTSS) District, which dates back a period of nearly 300 years and is of recognised cultural and historical significance. The settlement district comprises a scattering of stone footpaths, ancient walls and buildings. The footprint of NLES impacts upon some, but not all, representatives of these features. 21.4.101 Because of its high cultural heritage value, it is recommended that the TTSS be protected as much as possible, with as many of its stone features excluded from the design of NLES as possible. Whilst complete avoidance of the TTSS is the preferred approach, this option is not considered practicable, and a portion of two stone footpaths overlaps with the NLES footprint. Options for minimising impacts, including construction of a cavern to access relics, have been considered. However, the most practicable option involves creating a record of all relics to be lost prior to construction of the landfill. Where features cannot be preserved, these should be excavated and relocated to a visitor centre set up in the vicinity of the TTSS. The Ngong Tong area can be used for the landfill development but some graves with early dating and unique structural style should be preserved. If historic graves have to be removed before the commencement of the proposed construction, photographic and cartographic recording of the historic graves should be carried out by a qualified archaeologist in accordance with requirements provided by AMO. 21.4.102 NLES is considered likely to have acceptable impacts upon cultural heritage, if considered further in an EIA. However, the design should be developed in order to maximise the in-situ preservation of existing relics of the TTSS as far as possible, with survey and relocation of other elements of cultural heritage interest as required by AMO. 21.4.103 Part B of WLES is located over the existing boundary of the Tsang Tsui Archaeological Site (TTAS), that is a recorded item by AMO. Recent excavations in this area have revealed extensive remains of the late Neolithic period (c 2500-1500 BC). There is also a large grave of the Tang Clan, dating to the late Qing period (c. 100 years old). If historic graves have to be removed before the commencement of the proposed construction, photographic and cartographic recording of the historic graves should be carried out by a qualified archaeologist in accordance with requirements provided byAMO. There are no other declared, deemed or graded sites in the vicinity. 21.4.104 As construction of WLES would result in the loss of the TTAS, impacts upon cultural heritage are considered to be significant. Due to its location, opportunities to avoid the TTAS have been investigated but are considered unacceptable due to the significant loss in landfill capacity. For an acceptable development option at this site, relocation of the relevant features would be required. Details of the mitigation measures required would be subject to agreement with AMO during subsequent studies. 21.4.105 However the mitigation measures for these sites and their acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out.
Landscape and Visual Impacts 21.4.106 The following sections present a brief discussion of the merits or otherwise of each site in terms of landscape and visual impact.
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Sites with Overall Negative Low Landscape/Visual Impact 21.4.107 The sites considered to have an overall potential to cause low negative landscape and visual impacts include:
• Eastern Waters Island Landfill (EWIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); • Southeast Offshore Island Landfill (SEOIL); • Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES); and • WENT Landfill Extensions (WLES).
21.4.108 The site with the lowest landscape and visual impact is SEOIL. This is due to its remoteness from VSRs, especially land based ones, which are over 20km distant and who would not be significantly impacted by the project. In addition, the remoteness of the site from the coast and landscape context will serve to reduce its impacts on landscape character. 21.4.109 The land based landfills give rise to lower levels of landscape and visual impact than all other island sites, for the following reasons:
• They are located adjacent to existing landfills in areas where existing landscape character is somewhat degraded and where further landfilling will not appear wholly incongruous.
• They are also located in or adjacent to upland areas where they can be modelled to simulate surrounding upland topography, thus reducing impacts on landscape character. Upland locations also tends to reduce the extent of their visual envelopes;
• They are located in areas where population density and therefore the number of VSRs is low. 21.4.110 Of the land based sites, PPVNL has the least impact, as both the NLES and WLES are covered by landscape planning designations, which construction of the landfills will be contrary to. 21.4.111 EWIL will give rise to no landscape resource or landscape planning impacts. There will be impacts on landscape character due to the somewhat artificial character of the new island. The site will give rise to low levels of visual impact due to its distance from the shore, where for most of the time, it will be scarcely visible and due to the fact that only a relatively small number of VSRs are exposed to it, compared to those sites on the western side of Hong Kong. 21.4.112 TLWOIL will give rise to similar levels of landscape and visual impact to EWIL, However, these impacts will be slightly higher due to the closer proximity of the island landfill to the coast (giving rise to increased impacts on landscape character) and to recreational VSRs in Sai Kung East Country Park (giving rise to increased levels of visual impact). 21.4.113 Assuming sensitive development of the design in future studies, there is potential for mitigation proposals to be further refined at detailed EIA stage such that the significance of landscape and visual impacts are likely to be acceptable. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out.
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Sites with Overall Negative Low/High Landscape/Visual Impact 21.4.114 The sites considered to have an overall potential to cause low to high landscape and visual impacts include:
• Lantau Northwest Island Landfill (LNWIL); • Soko Islands Island Landfill (SIL); • Lamma Breakwater Island Landfill (LBIL); • South Cheung Chau Island Landfill (SCCIL); and • Lamma South Island Landfill (LSIL).
21.4.115 LNWIL will not give rise to landscape planning or resource impacts and is actually more remote from VSR centres of population than some of the other sites in this category. However, the landfill will have extremely high impacts on VSRs in Tai O due to its proximity to them and will have very significant impacts on the landscape character of Lantau coast, due to its coastal setting. 21.4.116 SIL will have no landscape planning or resource impacts. In addition, the landfill is located away from major VSR centres of population. The landfill's proximity to an overwhelmingly natural area of coastal landscape will give rise to very significant impacts on landscape character. 21.4.117 Similarly, LSIL will have no landscape planning or resource impacts. It is slightly more exposed visually to major VSR population centres than SIL (notably distant ones on Hong Kong Island), and will similarly have very significant impacts on the coastal landscape character of south Lamma. 21.4.118 LBIL, like the other sites in the Low/High ranking, does not give rise to landscape planning or resource impacts. It is however visually exposed to significant VSR centres on Hong Kong Island, Lamma, Cheung Chau, ferries etc. Its proximity to the coast of Lamma will mean that, like the sites above, it will give rise to very significant impacts on landscape character. 21.4.119 SCCIL will have no landscape planning or resource impacts. It is more visually exposed to VSR centres (notably on Lantau and on ferry routes) than the above sites and, like them, will have very significant impacts on landscape character. Sites with Overall Negative High Landscape/Visual Impact 21.4.120 The sites considered to have an overall potential to cause overall negative high landscape and visual impacts include:
• Deep Bay Island Landfill (DBIL); • Sha Chau Island Landfill (SCIL); • East Tung Lung Island Landfill (ETLIL); and • Lamma North Island Landfill (LNIL).
21.4.121 DBIL will give rise to indirect impacts on a designated Coastal Protection Area, but will not give rise to landscape resource impacts. Its proximity to the coast will give rise to very significant impacts on landscape character. In addition, the landfill will be extremely visible and will change the character of views of high numbers of VSRs in Shenzhen and those using the future Shenzhen Western Corridor. 21.4.122 SCIL will not give rise to landscape planning or resource impacts. It is however located close to significant centres of VSR population in Tung Chung and Tuen Mun as well as being exposed to the Hong Kong International Airport and the North Lantau Expressway. In addition, it will have a significant impact on the landscape character of Chi Shui-men and its relationship to the Pearl River Estuary.
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21.4.123 Assuming sensitive development of the design in future studies, there is potential for mitigation proposals to be further refined at detailed EIA stage such that the significance of landscape and visual impacts are likely to be acceptable. However their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out. 21.4.124 ETLIL will give rise to significant impacts on the designated Inshore Protection Area, but will not give rise to landscape resource impacts. Its proximity to the coast will mean that it gives rise to very significant impacts on the natural landscape character of the area. The area is also the locus of relatively high numbers of recreational receivers who will also experience high levels of visual impact. 21.4.125 LNIL will not give rise to landscape planning or resource impacts. However, its proximity to significant numbers of VSRs on Hong Kong Island, Lamma, Cheung Chau, Penny's Bay Theme Park and major ferry routes means that visual impacts will be extremely significant. In addition, its proximity to the coast of Lamma will result in very significant impacts on landscape character. 21.4.126 These sites are considered likely to have impacts that are "too excessive" and therefore "unacceptable" if considered further in an EIA. 21.4.127 To some extent, this assessment would depend on future development of the engineering designs and associated landscape and visual mitigation measures. However, the currently assessed “high” adverse landscape and visual impacts for these sites derive largely from the close proximity of the sites to valued landscapes and/or highly sensitive VSRs, and the ability to mitigate such impacts with mitigation measures is considered to be relatively low.
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21.5 Conclusions 21.5.1 Following on from a site selection exercise, this strategic environmental assessment has assessed the environmental impacts associated with the development and operation of twelve marine based new landfill sites, one new land based landfill site and two extensions to existing landfills. 21.5.2 Following assessment of the potential environmental impacts associated with the construction and operation of the landfill, each site has been assessed on the basis of whether it would have significant impacts if investigated further under the EIAO, or whether it is likely to have acceptable impacts if investigated further. Table 21.2 summarises the likely environmental acceptability of the sites under the EIAO, although it should be recognised that the environmental acceptability of any sites considered suitable for further investigation should be confirmed in an EIA Study, when more project details are available. 21.5.3 The following sites are considered likely to have insurmountable environmental impacts, if investigated further under the EIAO and are not recommended for further investigation:
• Deep Bay Island Landfill (DBIL); • Sha Chau Island Landfill (SCIL); • Lantau Northwest Island Landfill (LNWIL); • Soko Islands Landfill (SIL); • East Tung Lung Island Landfill (ETLIL); • Lamma North Island Landfill (LNIL); and • Lamma South Island Landfill (LSIL).
21.5.4 Recognising the qualitative nature of the assessment, the following sites are considered acceptable for further investigation however their overall acceptability needs to be confirmed in the EIA stage when more detailed analyses would be carried out:
• South Cheung Chau Island Landfill (SCCIL); • Lamma Breakwater Island Landfill (LBIL); • Eastern Waters Island Landfill (EWIL); • Tai Long Wan Offshore Island Landfill (TLWOIL); • Southeast Offshore Island Landfill (SEOIL); • Pillar Point Valley North Landfill (PPVNL); • NENT Landfill Extension (NLES); and • WENT Landfill Extensions (WLES).
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Table 21.2: Summary of Environmental Acceptability of Sites
Overall Acceptability
Site Air Quality Noise Water Quality Waste Management Ecology Fisheries Cultural Heritage Landscape & Visual Landfill Gas for Recommended Further Investigation
M.1 Deep Bay Island Landfill No
M.2 Sha Chau Island Landfill No
M.3 Lantau Northwest Island Landfill No
M.4 Soko Islands Landfill No
M.5 South Cheung Chau Island Landfill Yes
M.6 Lamma Breakwater Island Landfill ? Yes
M.7 East Tung Lung Island Landfill No
M.8 Eastern Waters Island Landfill ? Yes
M.9 Tai Long Wan Offshore Island Landfill ? Yes
M.10 Southeast Offshore Island Landfill Yes
M.11 Lamma North Island Landfill ? No
M.12 Lamma South Island Landfill No
L.1 Pillar Point Valley North Landfill Yes
E.1 NENT Landfill Extension ? Yes
E.2&3 WENT Landfill Extensions ? Yes
Notes: “” Denotes anticipated impacts likely to be acceptable “?“ Denotes anticipated impacts potentially high, requirements for mitigation would require further investigation “” Denotes anticipated impacts are not acceptable
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22. STRATEGIC ENVIRONMENTAL MONITORING AND AUDIT 22.1 Introduction 22.1.1 It should be noted at the outset that Strategic Environmental Monitoring and Audit (SEM&A) is not a higher-level version of the project Environmental Monitoring and Audit (EM&A), which assesses actual changes the physical environment as a result of the construction (and operation) of a project. 22.1.2 SEM&A should, perhaps, be referred to as Strategic Project Monitoring and Audit, since it identifies strategic-level actions to facilitate the development of a preferred option for a project in a sustainable manner. 22.1.3 This SEA has included a predominantly qualitative assessment of the potential impacts associated with the construction and operation of twelve marine based new sites, one new land based site and two extensions to existing landfills. To facilitate a strategic perspective on the overall evaluation of potential impacts, a methodology has been developed that accommodates the qualitative nature of the assessment and facilitates a consistent and transparent approach to the impact assessment. 22.1.4 It has been concluded that it is technically feasible to develop either a new marine based landfill site and / or an extension to an existing landfill site. The sites considered suitable for further investigation, (on environmental grounds) include:
• M.5 South Cheung Chau Island Landfill (SCCIL) • M.6 Lamma Breakwater Island Landfill (LBIL) • M.8 Eastern Waters Island Landfill (EWIL) • M.9 Tai Long Wan Offshore Island Landfill (TLWOIL) New Sites • M.10 South East Offshore Island Landfill (SEOIL) • L.1 Pillar Point Valley North Landfill (PPVNL)
• E.1 NENT Landfill Extension (NLES) Extensions at • E.2&3 WENT Landfill Extensions (WLES) Existing Landfills
22.1.5 Following this Study, the preferred site(s) will be subject to further investigation followed by preparation of preliminary designs upon which a quantitative Environmental Impact Assessment will be carried out in accordance with the EIA Ordinance. 22.1.6 By addressing key environmental issues during the early stages of a project, there remains sufficient flexibility in the design process to maximise opportunities for impact avoidance, such that the need for impact mitigation is reduced as far as is practicable and applied only where absolutely necessary. Key environmental issues associated with each of the individual sites considered acceptable are discussed in the relevant Sections of Part B of this SEA. This Section identifies the key areas that should be addressed and investigated further, during the subsequent stages, in the development of the overall project. The purpose of this section is to:
• Highlight key design issues that should be addressed as the project develops; and • Identify strategic-level actions to facilitate the development of a preferred option in a sustainable manner.
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22.2 Design Issues to be taken into Account During the Development of a New Landfill Site / Extension to an Existing Landfill Site 22.2.1 The SEA has identified that the potential environmental impacts caused by the preferred development options fall into two distinct groups, depending on whether the options are land or marine based. These issues will need to be examined in detail during the EIA stage to confirm that the baseline environmental conditions and assumptions made in this SEA have not altered and that the findings of the SEA remain valid. 22.2.2 Generic approaches to mitigation of impacts are presented in Part A of this SEA, and likely requirements for each site have been identified in Part B. At the next stage of the project, further refinement of the design can ultimately reduce the overall need for mitigation. The following sections set out recommended design issues for further consideration during the project development; these are summarised in Table 22.1.
Marine Water Quality Issues 22.2.3 As discussed in Chapter 21, marine based sites have the benefit of being able to accommodate the projected surplus of inert C&D material. However, at a local level, the primary environmental issue associated with marine based development is that it has the potential to impact directly upon marine water quality and indirectly upon marine ecological and fisheries resources. 22.2.4 Opportunities to minimise such impacts are a key consideration that should be focused upon throughout the development of the design. To refine the findings of the territory-wide water modelling carried out under this Study, it is recommended that a local hydrodynamic and water quality model be developed for the selected site. This will accommodate changes in the future baseline situation, (such as changes in water quality inputs from other sources) and facilitate development of the optimal environmentally friendly design. This may be achieved in a number of ways, including, repositioning of the artificial island within the site search envelope, refinement of the island shape, and the re-consideration of the layout of landfill infrastructure and afteruse facilities, including discharge points. 22.2.5 The refined model should be a 3-D hydrodynamic and water quality model (such as Delft- 3D) with a sufficiently fine grid at key flow channels and around the island site to reflect in detail the influence of the island configuration. It is suggested that a 25 m grid size in the vicinity of the island should be adequate for detailed modelling. In addition, the refined model should cover all sensitive receivers and water control zones locations where notable impacts have been predicted by the wider model used in this current Study. 22.2.6 Water quality modelling carried out in this Study aimed at addressing the water quality and hydrodynamic impacts. However, the morphological changes such as change in coastline, potential erosion or siltation should also be assessed in the later detailed study stage. 22.2.7 In addition, the water quality modelling has assumed a worst case scenario in which dredging would be necessary for all sites and the modelling assumptions are listed in Appendix I – an extract of the Final Water Quality and Hydrodynamic Assessment Report for future reference. However, the Study does aim to minimise dredging as far as practicable. This approach should remain the principal focus of the design process whilst ensuring the overall integrity of the site. The “no-dredge” option should be pursued in line with a risk assessment of the effects of major storm events on the integrity of exposed seawalls and the landfill liner.
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Landscape Design and Landfill Optimisation 22.2.8 The design schemes presented in the SEA are based upon current assumptions regarding waste arisings and are preliminary in nature. As discussed further in Section 22.3, a strategic follow up recommendation is to refine the projections of waste arisings to facilitate the development of detailed designs, which are based upon the specific capacity requirements of landfills extensions and / or new sites. The detailed designs should ensure that the profiles and elevations of landfills optimise the void space available for landfilling whilst balancing the landscape and visual issues. 22.2.9 For artificial island sites, in order to maximise the available void space, the feasibility of utilising inert residues from waste treatment in the construction of the reclamation (upon which the landfill would be constructed) should be investigated further, including an assessment of both the technical and environmental impacts. By diverting these materials away from the landfill itself, this approach would provide greater void space for non-inert solid wastes.
Best Practice Design in Landfill Technologies 22.2.10 Hong Kong has designed and implemented some of the most sophisticated landfill environmental control technologies in the world. The application of the best available technology should continue through subsequent stages of this project. International best practice should be monitored in tandem with local experience, to ensure appropriate design of wastewater and leachate treatment facilities, as well as those for landfill gas management such as extraction, flare, capping and liner technologies. Due to the long-term nature of the project, overall selection of technologies should take in to account “whole life” costing, including consideration of capital costs and recurrent costs.
Greenhouse Gas Issues 22.2.11 In Hong Kong, Municipal Solid Waste (MSW) is the primary source of methane, which is a Greenhouse Gas (GHG). Thermal oxidation of methane to carbon dioxide and water reduces the overall global warming effect of the MSW, as CO2 has a lower GWP than CH4 (as discussed in Section 2) The resultant energy can be put to beneficial use, providing power for adjacent, or on-site facilities. It is recommended that opportunities to minimise the long-term contribution of solid waste to Hong Kong’s GHG emissions are explored further. 22.2.12 Whilst potential landfill afteruse development is not within the scope if this Study, opportunities to develop afteruse facilities that can utilise the surplus energy should be explored further. This is considered further as a Strategic Follow Up Action in Section 22.3, below. 22.2.13 For the key design considerations shown in Table 22.1 there are no auditable targets to be achieved. Specific measures for formal monitoring and audit are not considered necessary. Measures and requirements should be included in Study Briefs for future design elements of the overall project and the opportunities evaluated accordingly.
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Table 22.1: Design Issues to be Pursued During Development of the Project in order to Minimise Environmental Impacts
Site Issue Action Implementation Implementation Stage Agent
All Sites Manage regional contribution Minimise CH4 emissions and off-set contributions of GHG from other Feasibility Study: Environmental of GHG and reduce the sources: Maximise utilisation of LFG derived energy on-site, and Preliminary Design Consultant & requirement for provision of further explore possible offsite uses of LFG, or consider potential Environmental power to future landfill afteruse landfill afteruse developments which can utililse LFG derived energy. Protection Department facilities. Ensure long-term best practice Monitor international development and implement Best Available Feasibility Study: Engineering Consultant approach to design of waste Technology for design of wastewater treatment facilities and leachate Preliminary Design / water treatment facilities & treatment plant to ensure compliance with discharge standards, Detailed Design landfill Liner taking in to account whole-life costing. Ensure long-term best practice Monitor international development and implement Best Available Feasibility Study: Engineering Consultant approach to design of LFG Technology for design of LFG treatment management facilities to Preliminary Design / treatment facilities ensure compliance with air quality objectives taking in to account Detailed Design whole-life costing. Maximise void space whilst Develop designs to ensure that profiles and elevations of landfill sites Feasibility Study: Environmental balancing landscape & visual optimize void capacity for landfilling whilst balancing potential adverse Preliminary Design / Consultant and impacts landscape and visual impacts. Detailed Design Engineering Consultant Marine Sites Further reduction of water Carry out refined hydrodynamic (HD) and water quality (WQ) Feasibility Study: EIA Environmental quality impacts and secondary modelling using a local model of the selected site and key areas Consultant impacts on ecology / fisheries predicted to be impacted by the wider model grid used in this Study. Optimise position of site within site search envelope on basis of Feasibility Study: EIA Environmental additional WQ and HD modelling exercise Consultant Optimise environmental benefits of Island shape and layout of landfill Feasibility Study: EIA Environmental infrastructure facilities on basis of additional WQ and HD modelling Consultant and exercise incorporating possible afteruse discharge emissions. Engineering Consultant Further reduction of water Confirm viability of no-dredge opportunities in the construction of the Feasibility Study: Engineering Consultant quality impacts & Minimise artificial island. Preliminary Design / volumes of dredged mud Detailed Design requiring management Maximize void space of new Investigate opportunities to utilise inert residues from waste treatment Feasibility Study Engineering Consultant landfills in the construction of the artificial island to divert them from the landfill Preliminary Design site itself.
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22.3 Strategic Follow Up Actions 22.3.1 In addition to the design issues, which may affect the overall environmental impacts, there are also certain broader issues that could be adopted to maximise strategic environmental benefits and allow improved planning to minimise project level impacts. To achieve this aim, the following sections set out recommendations for consideration by ETWB, these are summarised in Table 22.2.
Explore Interface with Complimentary Projects 22.3.2 This Study has identified an opportunity to utilise the projected surplus of inert C&D material (public fill) over the next 30 years for the formation of marine sites prior to construction of the landfill. The preferred arrangements to manage the projected surplus of public fill (as well as uncontaminated dredged mud) are being investigated under a separate study, Agreement No. CE 46/2000: Study on the Long Term Arrangements to Accommodate Inert Construction and Demolition Materials and Uncontaminated Dredged Mud, (C&D Materials Study) by the Civil Engineering Department. The recommendations of the C&D Materials Study are to utilise the surplus public fill for the construction of an artificial island. The C&D Materials Study also includes an investigation of possible afteruses to be developed on the formed land, one of which includes landfill development. 22.3.3 As the two projects progress, it is recommended that a co-ordinated approach is adopted to maximise the strategic environmental benefits of utilising the C&D material.
Maximise Afteruse Development Opportunities for Strategic Planning of “Bad Neighbour” Environmental Infrastructure 22.3.4 The development of landfill extensions and new sites will ultimately result in the formation of land, which can be developed for public facilities. Due to their relatively close proximity to residential areas, afteruse recreation opportunities on Hong Kong’s existing closed landfills have focused upon passive development for the surrounding community. Given the particularly remote location of marine sites considered suitable for landfill development, an opportunity also exists to utilise the formed land to develop necessary infrastructure, (e.g. waste to energy facilities, correctional services facilities, etc.) which, if built on existing land, would likely cause objection by local residents, or (because of their need to be located in remote areas) could result in environmental impacts upon previously undisturbed areas. 22.3.5 At this early stage in project development, afteruse requirements cannot be readily defined, however, the future requirements and any resultant implications for site size and method of construction, should be considered and it is recommended that an interdepartmental group be developed to review the likely afteruse opportunities.
Review Waste Management Plan & Refine Projections of Municipal Solid Waste Arisings and C&D Materials Arisings 22.3.6 For both this Study and the C&D Materials Study, the anticipated size and construction programme of sites has been determined on the basis of the overall size of available areas (following the constraints mapping site search exercises) and the predicted rate of materials generation over the project horizon. Under both studies, the materials generation models were based on number of materials generation scenarios, which took into account various combinations of assumptions, such as the introduction of landfill charging. The actual volume and timing of the generation of MSW and C&D material can have a profound influence over the environmental impacts of marine landfill site formation, as there is a direct correlation between the rate of filling and the release of fines into the water column.
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22.3.7 Whilst CED’s Public Fill Committee (PFC) maintains a register of anticipated public fill generation, it is recommended that the landfill expectancy model and overall review of any waste management programme be reviewed regularly. A longer term Strategic Plan is also recommended, which takes in to account the long-term infrastructure needs. The review of the life expectancy model should encompass the effects of issues such as the introduction of landfill charging, introduction of waste to energy facilities, as well as wider measures such as those being introduced under the Waste Reduction Framework Plan. The model could then be used during the development of new landfill sites, to allow more accurate determination of landfill development programme and facilitate future waste management planning beyond the scope of this current Study.
Define Sustainability of Landfills Extensions and Development of New Sites in the Context of Other Waste Management Initiatives. 22.3.8 In the evaluation of potential impacts, this SEA has broadly taken into account issues of sustainability (as described in Section 2.4). However, in order to ensure the proposals adhere to the principles of sustainability and to facilitate transparent and informed decision- making, it is recommended that a formal Sustainability Assessment (SA) is carried out using the Computer Assisted Sustainability Evaluation Tool (CASET). The CASET SA evaluation should include various scenarios relating to the implementation of other proposed waste management strategies, such as the C&D Materials Study, the potential waste to energy facility, and the proposals for management of contaminated dredged muds. This process would be a progression of the “View Sharing Meeting on Future Landfill Development in Hong Kong”, held in March 2001 and could be coupled with a public consultation exercise to maximise the overall sustainability of Hong Kong’s long-term waste management strategy.
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Table 22.2. Strategic Follow Up Actions Recommended for the Development of Selected Landfills Extensions and New Landfill Sites
Issue Proposed Action Implementation Explore Interface with As the two projects progress, it is recommended that a co-ordinated ETWB to consolidate projects, Consider joint Complimentary Waste approach be investigated to maximise the strategic environmental benefits EPD/CED task force for development. Management Projects of utilising the C&D materials. Maximise Afteruse Development Due to their particularly remote locations, new marine based sites present ETWB to consider establishing joint landfill Opportunities for Strategic opportunities to develop afteruses that could present significant afteruse development task force (comprising Planning of “Bad Neighbour” environmental and social dis-benefits if developed elsewhere in Hong e.g. EPD, PlanD, CSD) to determine long-term Environmental infrastructure Kong. Long term planning needs of such facilities should be considered in afteruse development opportunities. the planning of afteruse developments. Review Waste Management Predictions of materials arising (including public fill for marine sites and On the basis of the landfill life expectancy model Plan & Refine Projections of municipal solid waste arisings) are based on a variety of assumptions developed under this Study EPD to continue to Municipal Solid Waste Arisings subject to external influences (such as implementation of landfill charging monitor and refine projected arisings. and C&D Materials Arisings etc). Review the waste management programme, and introduce a longer Term Strategic Plan, encompassing a review of the Hong Kong landfill life expectancy model to facilitate the planning and implementation of landfills extensions and development of new sites as well as longer term waste management strategies. Define Sustainability of Landfills Carry out a formal SA, using CASET, and a public consultation exercise SDU and EPD to conduct CASET evaluation of Extensions and Development of taking in to account different development scenarios, including the landfill extensions/new sites final New Sites in the Context of implementation of other waste management measures currently being recommendations as well as other waste Other Waste Management investigated. management initiatives. Initiatives.
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22.4 The Next Steps 22.4.1 This Section has identified both environmental design-related issues that should be taken forward in to the next phases of the development of the design, as well as more strategic issues for consideration by Government. 22.4.2 Design issues discussed in Section 22.2 should be implemented through the specific consultant’s Briefs for the preliminary design and in the detailed design. Government should consider the strategic EM&A recommendations discussed in Section 22.3 further and an appropriate action plan should be developed following internal consultation and consideration of the most appropriate implementation strategy.
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APPENDIX I EXTRACT OF FINAL WATER QUALITY AND HYDRODYNAMIC ASSESSMENT REPORT (NOVEMBER 2002)
Final SEA Report – Appendix I \enviro\r\98347\FinalSEA\Divider
Hydrodynamic and Water Quality Modelling Services Scott Wilson (Hong Kong) Ltd For Potential New Waste Disposal Sites – Final Water Quality and Hydrodynamic Assessment Report
1. INTRODUCTION
1.1.1.1 Scott Wilson (Hong Kong) Ltd was commissioned by Environmental Protection Department (EPD) to carry out the Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites Study under Agreement No. CE 45/99. Environmental Management Ltd is the sub-consultant of Scott Wilson to undertake preliminary water quality modelling of reclaimed and offshore sites.
1.1.1.2 An artificial island would be constructed to provide new land for provision of a landfill site. The fill materials to be used for filling consist of inert construction and demolition (C&D) materials and uncontaminated sediment. The major components of the C&D materials are rock, soil and concrete. The carrying out of filling activities would cause the release of fines and sediment particles into the surrounding water environment leading to water pollution. After the completion of the filling operations, the artificial island would be formed. The presence of the artificial island may change the hydrodynamic and water quality conditions in the surrounding waters.
1.1.1.3 The purpose of the modelling works is to determine the feasibility of the potential new waste disposal sites through the assessment of the potential impacts on hydrodynamic and water quality during the construction and operation of the Project. Figure 1.1 shows the locations of the potential sites for construction of the artificial island. The Sites are divided into Western Sites and Eastern Sites and are listed as follows:
Western Sites • M1 – Deep Bay • M2 – Sha Chau • M3 – Lantau Nouthwest • M4 – Soko Islands • M5 – South Cheung Chau Disposal Ground • M6 – Lamma Breakwater • M11 – Lamma North • M12 – Lamma South
Eastern Sites • M7 – East Tung Lung Chau • M8 – Eastern Waters • M9 – Tai Long Wan Offshore • M10 – South East Offshore
1.1.1.4 This report presents the assessment of the potential hydrodynamic and water quality impacts during the construction and operation of the Project. The modelling methodology and relevant legislation and guidelines for the assessment are included and the approach to assess the water quality impacts arising from the construction and operational phases of the Project are also presented.
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1.1.1.5 The structure of this report is outlined as follows:
Section Title Content
1 Introduction General introduction of the background of the Study and the purpose of the report
2 Legislation and Legislation and guidelines relevant to the water Guidelines quality impact assessment of the present study
3 Key Water Quality A list of the key water quality parameters to be Parameters and assessed and identification of water quality Sensitive Receivers sensitive receivers
4 Modelling Tools Description of the model set up, model input data and model verification
5 Model Runs Details of the baseline, construction phase and operational phase model runs 6 Operational Phase Discussion of the changes in hydrodynamic and Modelling Results water quality conditions due to the presence of the artificial island. 7 Construction Phase Sediment plume modelling results for the Modelling Results assessment of the increase in suspended solids (SS) levels in the surrounding waters and the nearby water quality sensitive receivers during the construction phase. 8 Summary and Conclusion of the assessment Conclusion
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2. LEGISLATION AND GUIDELINES
2.1.1.1 The relevant legislation and guidelines to be used for water quality impact assessment within the Hong Kong waters include: • Water Pollution Control Ordinance (WPCO) Chapter 358 (as amended by the Water Pollution Control (Amendment) Ordinance 1990 and 1993); • Water Pollution Control (General) Regulations (as amended by the Water Pollution Control (General) (Amendment) Regulations 1990 and 1994); • Environmental Impact Assessment Ordinance (EIAO) (Cap. 499), Technical Memorandum on Environmental Impact Assessment Process (EIAO-TM), Annexes 6 and 14; • Water Quality Objectives (WQOs) for relevant Water Control Zones (WCZs).
2.1.1.2 The 12 potential new waste disposal sites for construction of the artificial island fall within the following WCZs: • Deep Bay Water Control Zone (DBWCZ); • North Western Water Control Zone (NWWCZ); • North Western Supplementary Water Control Zone (NWSWCZ); • Second Southern Supplementary Water Control Zone (SSSWCZ); • Southern Water Control Zone (SWCZ); and • Mirs Bay Water Control Zone (MBWCZ).
2.1.1.3 Table 2.1 summarizes the WQOs for marine waters in Hong Kong.
2.1.1.4 The Water Supplies Department (WSD) issued Water Quality Objectives of Sea Water for Flushing Supply (at intake point). The criteria for assessing the water quality impacts on the WSD’s seawater intakes will be based on the objectives shown in Table 2.2.
2.1.1.5 The locations of some of the Sites are near the waters in Shenzhen. The assessment of the water quality impacts within the Mainland waters will make reference to the Sea Water Quality Standard (GB3097-1997) established under the National Standard of the People’s Republic of China UCD 551463. Table 2.3 shows some of the selected parameters included in the Sea Water Quality Standard.
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Table 2.1 Summary of Water Quality Objectives (WQOs) for Marine Waters of Hong Kong
Parameters Water Quality Objective Water Control Zone (WCZ)/Part(s) of zone/Subzones to which the WQOs apply
D.O. (within 2 Not less than 2 mg/L for 90% samples Marine waters of all WCZs except Tolo Harbour & Channel WCZ m of bottom) D.O. (Depth Not less than 4 mg/L for 90% samples Marine waters of all WCZs except Tolo Harbour & Channel WCZ averaged) D.O. (within 2 Not less than 2mg/L Harbour Subzone, Tolo Harbour & Channel WCZ m of bottom) Not less than 3mg/L Buffer Subzone, Tolo Harbour & Channel WCZ Not less than 4mg/L Channel Subzone, Tolo Harbour & Channel WCZ D.O. (rest of Not less than 4mg/L Tolo Harbour & Channel WCZ – whole zone water column) Nutrients Not to be present in quantities that Marine waters of all WCZs except Tolo Harbour & Channel WCZ cause excessive algal growth Nutrients Annual mean depth average inorganic Marine waters of Southern WCZ and Port Shelter WCZ nitrogen not to exceed 0.1 mg/L Annual mean depth average inorganic Marine waters of Mirs Bay WCZ, Junk Bay WCZ, North Western nitrogen not to exceed 0.3 mg/L WCZ (Castle Peak Subzone) Annual mean depth average inorganic Marine waters of Eastern Buffer WCZ, Western Buffer WCZ, nitrogen not to exceed 0.4 mg/L Victoria Harbour WCZ Annual mean depth average inorganic Marine waters of Deep Bay WCZ (Outer Subzone) and North nitrogen not to exceed 0.5 mg/L Western WCZ (Whole zone except Castle Peak Subzone). Annual mean depth average inorganic Marine waters of Deep Bay WCZ (Inner Subzone) nitrogen not to exceed 0.7 mg/L Unionized Annual mean not to exceed 0.021 All WCZs (whole zone) except Tolo Harbour & Channel WCZ ammonia mg/L E.coli Annual geometric mean not to exceed Secondary contact recreation subzones in Tolo Harbour & 610cuf/100mL Channel WCZ, Southern WCZ, Port Shelter WCZ, Mirs Bay WCZ, Deep Bay WCZ, North Western WCZ, Western Buffer WCZ Annual geometric mean not to exceed Fish culture subzones in Tolo Harbour & Channel WCZ, Southern 610cuf/100mL WCZ, Port Shelter WCZ, Junk Bay, Mirs Bay WCZ, Deep Bay WCZ, Eastern Buffer WCZ, Western Buffer WCZ pH To be in the range 6.5 – 8.5, change Marine waters of all WCZs except Tolo Harbour & Channel WCZ due to waste discharge not to be exceed 0.2 pH Change due to waste discharge not to Harbour Subzone, Tolo Harbour & Channel WCZ be greater than ±0.5 Change due to waste discharge not to Buffer Subzone, Tolo Harbour & Channel WCZ be greater than ±0.3 Change due to waste discharge not to Channel Subzone, Tolo Harbour & Channel WCZ be greater than ±0.1 Salinity Change due to waste discharge not to All WCZs (Whole zone) except Tolo Harbour & Channel WCZ exceed 10% of natural ambient level Change due to waste discharge not to Tolo Harbour & Channel WCZ be greater than ±3ppt Temperature Change due to waste discharge not to All WCZs (Whole zone) except Tolo Harbour & Channel WCZ exceed 20C Change due to waste discharge not to Tolo Harbour & Channel WCZ exceed 10C Suspended Waste discharge not to raise the Marine waters of all WCZs except Tolo Harbour & Channel WCZ solids natural ambient level by 30% nor cause the accumulation of suspended solids which may adversely affect aquatic communities Toxicants Not to be present at levels producing All WCZs (Whole zone) significant toxic effect Chlorophyll-a Not to exceed 20mg/m3(µg/L) Harbour subzone, Tolo Harbour & Channel WCZ calculated as running arithmetic mean of 5 daily measurements for any location and depth Not to exceed 10mg/m3(µg/L) Buffer Subzone, Tolo Harbour & Channel WCZ calculated as running arithmetic mean of 5 daily measurements for any location and depth Not to exceed 6mg/m3(µg/L) Channel Subzone, Tolo Harbour & Channel WCZ calculated as running arithmetic mean of 5 daily measurements for any location and depth
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Table 2.2 Water Quality Objectives of Sea Water for Flushing Supply (at Intake Point) Parameters Target Colour (H.U.) < 20 Turbidity (N.T.U.) < 10 Threshold Odour No. < 100 Ammonical Nitrogen (mg/L) < 1 Suspended Solids (mg/L) < 10 Dissolved Oxygen (mg/L) > 2 Biochemical Oxygen Demand (mg/L) < 10 Synthetic Detergents (mg/L) < 5 E.coli (count per 100 mL) < 20,000 Source: Water Supplies Department, Hong Kong
Table 2.3 Relevant Mainland Sea Water Quality Standard No Item Category 1 Category 2 Category 3 Category 4 1 Floating matter No oil film, floating foam and other debris on water No obvious oil film, floating foam and other surface debris on water surface 2 Colour, Odour, Taste No abnormal colour, odour and taste should be presented No disgusting colour, odour and taste should in sea water be presented in sea water 3 Suspended matter Man-made Man-made increment ≤ 100 Man-made increment ≤ 150 increment ≤10 4 Coliform index 10000; ≤ 700 for shellfish culture zone － (count/L) 5 Faecal coliform 2000; ≤ 140 for shellfish culture zone － (count/L) 6 Pathogen Should not be contained in the water of shellfish culture zone 7 Temperature (°C) Man-made increment should not Man-made increment should not exceed 4 exceed 1 in summer and 2 in other seasons 8 pH 7.8 - 8.5 and change in pH level 6.8～8.8 and change in pH level should not exceed 0.5 pH unit as should not exceed 0.2 pH unit as compared to the ambient level compared to the ambient level 9 Dissolved oxygen > 6 > 5 > 4 > 3 10 Chemical oxygen ≤ 2 ≤ 3 ≤ 4 ≤ 5 demand（COD） 11 Biochemical oxygen ≤ 1 ≤ 3 ≤ 4 ≤ 5
demand (BOD5） 12 Inorganic（as N） ≤ 0.20 ≤ 0.30 ≤ 0.40 ≤ 0.50 13 No-ionic ammonia ≤ 0.020 (as N） 14 Activated phosphate ≤ 0.015 ≤ 0.030 ≤ 0.045 (as P） 15 Mercury ≤ 0.00005 ≤ 0.0002 ≤ 0.0005 16 Cadmium ≤ 0.001 ≤ 0.005 ≤ 0.010 17 Lead ≤ 0.001 ≤ 0.005 ≤ 0.010 ≤ 0.050 18 Chromium (VI) ≤ 0.005 ≤ 0.010 ≤ 0.020 ≤ 0.050 19 Total Chromium ≤ 0.05 ≤ 0.10 ≤ 0.20 ≤ 0.50 20 Arsenic ≤ 0.020 ≤ 0.030 ≤ 0.050 21 Copper ≤ 0.005 ≤ 0.010 ≤ 0.050 22 Zinc ≤ 0.020 ≤ 0.050 ≤ 0.10 ≤ 0.50 23 Selenium ≤ 0.010 ≤ 0.020 ≤ 0.050 24 Nickel ≤ 0.005 ≤ 0.010 ≤ 0.020 ≤ 0.050 Remarks: 1. Category 1 represents marine fisheries zone, marine natural reserve area and critically endangered marine habitat protection area; 2. Category 2 represents marine cultural zone, marine bathing water, secondary contact or marine recreation area, and marine water which is directly related to human consumption; 3. Category 3 represents marine water for general industrial use and marine scenic area; 4. Category 4 represents marine harbour area and marine development area; and 5. All units in mg/L unless otherwise stated. Source: Sea Water Quality Standard GB3097-1997
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3. KEY WATER QUALITY PARAMETERS AND SENSITIVE RECEIVERS
3.1 Key Water Quality Parameters
3.1.1.1 The key concern during the construction phase of the Project is the release of contaminants from the filling actives. The fill materials are mainly inert C&D materials and uncontaminated sediment, and would not contain biodegradable and toxic substances. Sediment plume modelling will therefore be conducted to assess the increase in suspended solids (SS) levels in the surrounding waters and the nearby water quality sensitive receivers.
3.1.1.2 For the operational phase, the changes in hydrodynamic and water quality conditions due to the presence of the artificial island are of concern. The flushing capacity through the major channels in Hong Kong will be calculated to determine the reduction rate. The major water quality parameters assessed for the operational phase impact assessment include dissolved oxygen (DO), salinity, total inorganic nitrogen (TIN), unionized ammonia (UIA), SS, and E.coli.
3.2 Sensitive Receivers
3.2.1.1 The Western and Eastern Sites are located within 4 WCZs and 2 supplementary WCZs. The influence from the Sites may depend on the distance between the Sites and the locations of the affected areas. The water quality sensitive receivers that are potentially affected by this Project may include:
Hong Kong Waters • Marine parks at Sha Chau and Lung Kwu Chau, Yan Chau Tong, Hoi Ha Wan, Tung Ping Chau and a marine reserve at Cape D’Aguilar • Potential marine parks/marine reserve near Fan Lau, south of Lamma Island, Shelter Island, Long Ke Wan and Tai Long Wan Region, Ninepin Islands and Soko Islands • Finless Porpoise Area • Seagrass bed and horseshoe crab area near Ha Pak Nai • Chinese White Dolphin feeding ground in the area covering Urmston Road Channel, and in the waters north, east and south of Lantau Island • Secondary contact recreational zones • Gazetted beaches • Fish culture zones • Cooling water intakes • Pak Nai Site of Special Scientific Interest (Pak Nai SSSI) • Tai Long Wan SSSI • Oyster beds near Lau Fau Shan and Pak Nai • Mai Po Nature Reserve in the Inner Deep Bay • Tsim Bei Tsui SSSI • WSD seawater intakes • Sensitive coral areas such as near Beaufort Island, Tung Lung Chau and Ching Chau • Proposed Fisheries Protection Area (FPA) at Port Shelter
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Mainland Waters • Oyster beds at Shekou • Mangroves and mudflat at Futian • Swimming beaches • Fish, scallop and rockshore culture area
3.2.1.2 Table 3.1 lists the potential water quality sensitive receivers to be included in the water quality models. The locations of these sensitive receivers are shown in Figure 3.1a and 3.1b. Figure 3.2 shows the secondary contact recreation zones.
3.2.1.3 The EPD marine water sampling stations within the concerned WCZs and in the WCZs close to the potential waste disposal sites are also included in the models as indicator points. Figure 3.3 shows the locations of these stations.
Table 3.1 Water Quality Sensitive Receivers No. Sensitive Receivers 1 CW1 Cooling Water Intake at Black Point 2 CW2 Cooling Water Intake at New Air Port 3 CW3 Cooling Water Intake at Tsing Yi 4 CW4 Cooling Water Intake at Lamma Island & Gazetted Beach at Lamma Beach 5 CW5 Cooling Water Intakes near Wanchai 6 CW6 Cooling Water Intakes at South East Kowloon Development 7 CW7 Cooling Water Intakes at Castle Peak Power Station 8 FC1 Fish Culture Zone at Ma Wan 9 FC2 Fish Culture Zone at Cheung Sha Wan 10 FC3 Fish Culture Zone at Lo Tik Wan 11 FC4 Fish Culture Zone at Sok Kwu Wan 12 FC5 Fish Culture Zone at Tung Lung Chau 13 FC6 Fish Culture Zone at Po Toi O 14 FC7 Fish Culture Zone at Ma Nam Wat & Gazetted Beach at Trio Beach 15 FC8 Fish Culture Zone at Kau Sai 16 FC9 Fish Culture Zone at Leung Shuen Wan 17 FC10 Fish Culture Zone at Kai Lung Wan 18 FC11 Fish Culture Zone at Tai Tau Chau 19 FC12 Fish Culture Zone at Tap Mun 20 FC13 Fish Culture Zone at Wong Wan 21 FC14 Fish Culture Zone at O Pui Tong 22 FN1a-d Fisheries Protection Area (FPA) at Port Shelter 23 FP1 Finless Porpoise Area (near Lamma Island South) 24 FP2 Finless Porpoise Area Fishery Nursery/Spawning Ground near Cheung Chau 25 FP3 Finless Porpoise Area (near Mong Tung Wan, Lantau Island) 26 FP4 Finless Porpoise Area (near Tung Wan, Lantau Island) 27 FP5 Finless Porpoise Area (near Wong Ma Kok) 28 FP6 Finless Porpoise Area (near Po Toi)
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No. Sensitive Receivers 29 FP7 Finless Porpoise Area (offshore to the South of Lantau Island) 30 FP8 Finless Porpoise Area (near Lamma Island East) 31 FP9 Finless Porpoise at Southeast Offshore Island Landfill 32 GB1 Gazetted Beaches in Tuen Mun District 33 GB2 Gazetted Beaches in Tsuen Wan District 34 GB3 Gazetted Beach at Cheung Sha 35 GB4 Gazetted Beach at Silvermine Bay 36 GB5 Gazetted Beach in Southern District 37 GB6 Gazetted Beach at Shek O 38 GB7 Gazetted Beach at Clear Water Bay 39 GB8 Gazetted Beaches at Kiu Tsui and Hap Mun Bay & Surveyed Coral near Sharp Island 40 GB9 Gazetted Beach at Hebe Haven 41 GB10 Gazetted Beach at Silverstrand 42 GB11 Gazetted Beaches in Cheung Chau (Tung Wan and Kwun Yan Wan) 43 GB12 Gazetted Beach at Tong Fuk 44 GB13 Gazetted Beach at Pui O 45 HC1 Horseshoe Crab Area near Tong Fuk 46 HC2 Horseshoe Crab Area Tai O South 47 HC3 Horseshoe Crab Area Tai O North 48 MA Mai Po Nature Reserve Area 49 MP1 Yat Chau Tong Marine Park 50 MP2 Hoi Ha Wan Marine Park 51 MP3 Sha Chau Lung Kwun Chau Marine Park 52 MP4 Tung Ping Chau Marine Park 53 MP5 Potential Marine Park/Marine Reserve near Fan Lau 54 MP6 Potential Marine Park/Marine Reserve to the South of Lamma Island 55 MP7 Potential Marine Park/Marine Reserve near Shelter Island 56 MP8 Potential Marine Park/Marine Reserve and SSSI at Tai Long Wan 57 MP8b Water Quality Monitoring Station at Tai Long Wan 58 MP9 Potential Marine Park/Marine Reserve at Long Ke, Pak Lap Tsai and Pak Lap 59 MP10 Potential Marine Park/Marine Reserve near North Ninepin Island 60 MP11 Potential Marine Park/Marine Reserve near South Ninepin Island 61 MP12 Potential Marine Park/Marine Reserve & Fishery Nursery/Spawning Ground near Soko Island 62 MP13 Potential Marine Park/Marine Reserve at South West Lantau 63 MR1 Cape D’ Aguilar Marine Reserve 64 NS1 Fishery Nursery/Spawning Ground South of Pak Tso Wan, Cheung Chau 65 NS2 Fishery Nursery/Spawning Ground South of Nam Tam Wan, Cheung Chau
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No. Sensitive Receivers 66 NS3 Fishery Nursery/Spawning Ground Southwest of Cheung Chau 67 NS4 Fishery Nursery/Spawning Ground South of Lamma Island 68 NS5 Fishery Nursery/Spawning Ground South of Lamma Island 69 NS6 Fishery Nursery/Spawning Ground North of Po Toi Island 70 NS7 Fishery Nursery/Spawning Ground near Sung Kong and Waglan Island 71 NS8 Fishery Nursery/Spawning Ground north of Ngai Tau, Lamma Island 72 NS9 Fishery Nursery/Spawning Ground off Sok Kwu Wan, Lamma Island 73 NS10 Fishery Nursery/Spawning Ground West of Cheung Chau 74 NS11 Fishery Nursery/Spawning Ground South of Lantau Island 75 OB1 Oyster Beds near Lau Fau Shan 76 SC1 Surveyed Corals and Green Turtle Site near Lamma Island North 77 SC2 Surveyed Corals near Round Island 78 SC3 Surveyed Corals near Beaufort Island 79 SC4 Surveyed Corals near Sun Kong Island 80 SC5 Surveyed Corals and Green Turtle Site near Tung Lung Chau 81 SC6 Surveyed Corals and Green Turtle Site near Nine Pine Island 82 SC7 Surveyed Corals and Green Turtle Site near Ching Chau 83 SC8 Surveyed Corals near Basalt Island 84 SC9 Surveyed Corals near Tolo Channel 85 SC10 Surveyed Corals near Ocean Point 86 SC11 Surveyed Corals near Po Toi Island 87 SC12 Surveyed Corals near Long Ke Wan 88 SC13 Surveyed Corals near Pak Lap Wan 89 SC14 Surveyed Corals near Victor Rock 90 SC15 Surveyed Corals & Potential Marine Park near Bluff Island 91 SC16 Surveyed Corals near Tai Lak Lei (Trio Island) 92 SC17 Surveyed Corals near Breakers Reef 93 SC18 Surveyed Corals near Waglan Island 94 SC19 Surveyed Corals near Soko Island 95 SC20 Surveyed Corals near Shek Kok Tsui, Green Island 96 SC21 Surveyed Corals near Wong Mau Chau 97 SI1 Pak Nai SSSI 98 SI2 Tsim Bei Tsui SSSI 99 SG Seagrass Bed and Horseshoe Crab Area at Ha Pak Nai 100 GT1 Green Turtle Site at Lamma Island 101 GT2 Green Turtle Site at Po Toi 102 GT3 Green Turtle Site near Port Island 103 WI1 WSD Sea Water Intake at Tuen Mum 104 WI2 WSD Sea Water Intake at Ap Lei Chau 105 WI3 WSD Sea Water Intake at Kennedy Town 106 WI4 WSD Sea Water Intake at Chai Wan 107 WD1 Chinese White Dolphin Feeding Ground
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No. Sensitive Receivers 108 WD2 Chinese White Dolphin Conservation Zone in Mainland waters (offshore to the southwest of Lantau Island) 109 WD3 Chinese White Dolphin in Mainland waters (offshore to the west of the New Airport) 110 RD Proposed Resort Development at Tai A Chau 111 MF Fish Culture Areas (Mainland Waters) 112 MF2 Fish/Scallop/Rockshore Culture Areas near Zhongxinzhou (Mainland Waters) 113 MF3 Fish/Scallop/Rockshore Culture Areas near Northern Guishan Island (Mainland Waters) 114 MF4 Fish/Scallop/Rockshore Culture Areas near Eastern Guishan Island (Mainland Waters) 115 MF5 Fish/Scallop/Rockshore Culture Areas near Zhizhou Islands (Mainland Waters) 116 MF6 Fish/Scallop/Rockshore Culture Areas near Zhizhou Islands (Mainland Waters) 117 MF7 Fish/Scallop/Rockshore Culture Areas near Aizhou Islands (Mainland Waters) 118 MF8 Fish/Scallop/Rockshore Culture Areas near Heizhou (Mainland Waters) 119 MF9 Fish/Scallop/Rockshore Culture Areas near Wailingding Island (Mainland Waters) 120 MF10 Fish/Scallop/Rockshore Culture Areas near Dong'ao Island (Mainland Waters) 121 MF11 Fish/Scallop/Rockshore Culture Areas near Baili Island (Mainland Waters) 122 MF12 Fish/Scallop/Rockshore Culture Areas near Hengzhou Island (Mainland Waters) 123 MF13 Fish/Scallop/Rockshore Culture Areas near Beijian Island (Mainland Waters) 124 MF14 Fish/Scallop/Rockshore Culture Areas near Erzhou Island (Mainland Waters) 125 MF15 Fish/Scallop/Rockshore Culture Areas near Dangan Island (Mainland Waters) 126 MG Mangroves at Futian (Mainland Waters) 127 OB2 Oyster Beds at Shekou (Mainland Waters) 128 SB Da & Xiao Mei Sha Swimming Beaches (Mainland Waters)
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4. MODELLING TOOLS
4.1 General
4.1.1.1 The Delft3D suite of models is used as a modelling platform for the hydrodynamic and water quality simulations. The Delft3D suite of models can perform 3- dimensional simulations of water movement and dispersion of pollutants with chemical reaction and decay. The vertical water column can be divided up to 10 layers for hydrodynamic computations. This reproduces the stratification condition in the water column.
4.1.1.2 The Delft3D suite of models consists of a range of modules to perform different types of simulation. The main modules that are applied in this study include Delft3D- FLOW and Delft3D-WAQ. The Delft3D-FLOW is programmed for hydrodynamic simulation. The key parameters of computations include water level, current magnitude, current direction, temperature and salinity. A set of governing equations for conservation of mass and momentum are solved numerically in this module.
4.1.1.3 The Delft3D-WAQ module, which incorporates the transport of substances and associated water quality processes, is for water quality simulation. This module allows physical transport, chemical / biological reactions, or accumulation of substances in the segments to calculate the concentrations of the substances. The water quality simulation can cover a wide range of substances such as suspended solids, biochemical oxygen demand, dissolved oxygen, E.coli, nutrients, etc. The water body is divided into homogeneous segments between which mass transport is allowed through the interfacial layer. This module is capable of simulating sediment plume dispersion generated from dredging and filling activities.
4.1.1.4 In this study, two detailed models with refined grid sizes have been used for hydrodynamic and water quality simulations. In addition, the Update model, which was developed under “Update on Cumulative Water Quality and Hydrological Effect of Coastal Development and Upgrading of Assessment Tool (Agreement No. CE42/97)” have also been used to provide boundary conditions to the two detailed models. This larger model covers the discharges from the major Pearl River estuaries, which include Humen, Jiaomen, Hongqili, Hengmen, Muodaomen, Jitimen, Hutiaomen and Aimen. The influences on hydrodynamics and water quality due to the discharges from Pearl River estuaries can be incorporated into the detailed models.
4.2 Detailed Models
Model Setup
4.2.1.1 Two detailed models namely the Western Model and the Eastern Model have been developed based on the Fine Grid Model and the Tolo Harbour Model to cover the Western Sites and Eastern Sites. The Fine Grid and Tolo Harbour Models had been calibrated for hydrodynamics under a separate study but not for water quality. The modelling domain of the Fine Grid Model covers all the Western Sites. Therefore, only water quality simulation has been verified for the Western Model under the present study. Expansion of the model coverage of the Tolo Harbour Model is
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required in order to cover all the Eastern Sites. Therefore, verification for both the hydrodynamic and water quality simulations has been conducted for the Eastern Model.
4.2.1.2 Model grid is generated using the Delft-RGFGRID module. Curvilinear grid lines are adopted to take into account the coastline configuration of the study area. This aims to achieve the requirements of smoothness and orthogonality. A high grid resolution is applied in the areas near the sensitive receivers, which are potentially affected by the Project, and the major channels. A low grid resolution is adopted in open waters. Figures 4.1 and 4.2 shows the grid schematizations for the Eastern and Western Models.
4.2.1.3 The bathymetry configurations of the Western and Eastern Models were interpolated from the bathymetry data adopted in the Fine Grid Model, Tolo Harbour Model and the Update Model. For the operational phase assessment, the bathymetry conditions as a result of forming the artificial island have been updated to reflect the size and shape of the island.
4.2.1.4 The coastline configurations for the detailed models have been updated based on the latest and planned coastal developments. The present Project is proposed to commence in 2007 and is expected to complete in 2025. Table 4.1 summarizes the major development and reclamation projects that have been incorporated into the models to form the coastline configurations.
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Table 4.1 Developments to be Included in Coastline Configurations Developments Construction Phase Operational Phase (2007 – before 2025) (2025) South East Kowloon √ √ Development – KTAC Reclamation, Hoi Sham (Earth Bund and Phase 1 Stages 1 & 2, and Kwun Tong Typhoon Shelter. South East Kowloon X (before 2011) √ Development – Hoi Sham √ (after 2011) Phase 1 Stage 3 and Phase 2 and Cha Kwo Ling Central Reclamation Phase III √ √ Wan Chai Development Phase √ √ II Tseung Kwan O Reclamation √ √ Jordan Road Reclamation √ √ Phase III Lamma Island Reclamation √ √ (Yung Shue Wan Development Engineering Works, Phase II) Container Terminal No. 9 √ √ Penny’s Bay Stages I & II √ √ Reclamation Peng Chau Reclamation √ √ Tuen Mun Area 38 √ √ Reclamation North Lantau Development √ √ Chok Ko Wan Link Road √ √ Reclamation North Tsing Yi District Open √ √ Space and Government, Institute and Community Facilities Reclamation Yam O Reclamation √ √ Yau Tong Bay Reclamation √ √ Pak Shek Kok and Ma Liu √ √ Shui Reclamation Notes: 1. √ represents the development to be included in the construction/operational phase model runs; 2. X represents the development not to be included in the construction/operational phase model runs; and 3. The sites proposed for Container Terminals CT10 and CT11 are reserved for the Theme Part at Penny’s Bay. Therefore, CT10, CT11 and the Lamma Breakwater will not be included in the model runs.
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4.2.1.5 The Western and Eastern Models are constructed as 3-dimensional detailed models to simulate the vertical structure of the water body and the distribution of pollutants in the water column.
4.2.1.6 The hydrodynamic computations of the detailed models provide input data to drive the water quality computations. The model set up for water quality simulation incorporates suitable meteorological forcing, initial and boundary conditions, flow aggregation and modelling substances. The substance file used for water quality simulation incorporates the substances of salinity, temperature, dissolved oxygen, suspended solids, BOD, E.coli, phytophankton, organic and inorganic nitrogen, phosphorus and silicate. In addition, the water quality simulation takes into account air-water exchange and benthic processes. The contaminant in the C&D materials would mainly contain suspended solids and this parameter would be the key factor to be determined in the construction phase water quality impact assessment. The other major parameters as included in the substance file have been considered to assess the changes in water quality during the operational phase of the project.
Simulation Period
4.2.1.7 Hydrodynamic and water quality model runs cover at least a real sequence of 15 days spring-neap tidal cycle in the dry and wet seasons. The model spin up covers 7 days prior to the actual model simulation period. Meanwhile, the 7-days spin-up uses ‘warm-start’ conditions, obtained from the Update Model results that had been simulated for 22 days. The proposed dry and wet season simulation periods are presented in Table 4.2.
Table 4.2 Model Simulation Periods Season Spin Up Model Start Time Model End Time Wet 19 July 2025 04:00 26 July 2025 04:00 10 August 2025 04:00 – 26 July 2025 04:00 Dry 2 Feb 2025 12:00 9 Feb 2025 12:00 24 Feb 2025 12:00 – 9 Feb 2025 12:00
Meteorological Forcing
4.2.1.8 The ambient environmental conditions are closely linked to the processes of water quality changes. Meteorological forcing including wind speed, solar surface radiation and water temperature for the dry and wet seasons need to be defined in the hydrodynamic and water quality computations of the detailed models. The data for meteorological forcing was based on the past records from Hong Kong Observatory.
4.2.1.9 The wind conditions applied in the hydrodynamic simulation are 5 m/s NE for dry season and 5 m/s SW for the wet season. Monthly averaged values of solar surface radiation and water temperature were used in the models. It is assumed that solar radiation and water temperature are constant over the entire domain of the models. Solar radiation is recorded only at King’s Park station by Hong Kong Observatory. The monthly averaged solar radiation was calculated based on the hourly data
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recorded at this station. The average values of solar radiation adopted are 132 W/m2 in the dry season and 237 W/m2 in the wet season.
4.2.1.10 The ambient water temperature was determined based on the EPD routine monitoring data collected within the WCZs. The average water temperature values used in the water quality models are 16 °C in the dry season and 29 °C in the wet season.
Initial and boundary conditions
4.2.1.11 The Western and Eastern Models are linked to the Update model. Hydrodynamic computations were first carried out using the Update model to generate the open boundary conditions for the two detailed models. In order to start the water quality model run from a more realistic condition, a longer spin-up period of two full spring/neap cycles was adopted prior to the actual water quality simulation. After performing the spin-up, the influence on initial conditions would be subsided and would not affect the concentrations of the simulated parameters.
Flow Aggregation
4.2.1.12 Aggregation of the hydrodynamics has been performed to reduce the vertical resolution from 10 layers to 5 layers. The vertical distribution of the layers for the detailed water quality model is 10%, 20%, 20%, 30% and 20% of the hydrodynamic layers from surface to bottom. This optimizes the computational time and data storage without a significant influence on the quality of the modelling results. A 2x2 flow aggregation was applied in the spatial level.
Model Outputs
4.2.1.13 Statistical analysis of water quality changes was conducted at representative indicator points near the filling sites. Some of the indicator points are located at the water quality sensitive receivers and at the same locations as EPD’s routine marine water sampling stations to check for WQO compliance. The locations of all the indicator points and EPD marine water sampling stations are shown in Figures 3.1a, 3.1b and 3.3.
4.2.1.14 Meanwhile, for hydrodynamic results, the impacts due to the proposed sites are assessed in terms of accumulated flow and current velocity. Figure 4.3 shows the location of the cross sections where the accumulated flow are assessed while Figure 6.1 shows the location of the indicator points where the current velocities are assessed.
4.2.1.15 The model outputs are presented in form of table, contour plot, vector plot and time series plot. All contour and vector plots in the operational and construction phase assessments are ‘snapshot’ results indicating periods at either “mid-flood” or “mid- ebb”. All results presented in the tables are depth-averaged (except for bottom DO) and time-averaged (except for 90%ile DO and 90%ile depth-averaged DO) values.
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5. MODEL RUNS
5.1.1.1 The model runs were divided into two packages. Package 1 model runs consist of Sites M4, M5, M6 (Western Sites) and M8 (Eastern Site). Package 2 model runs cover Sites M1, M2, M3, M11 and M12 (Western Sites) and Sites M7, M9 and M10 (Eastern Sites).
5.1.1.2 The modelling scenarios for each of the packages include the baseline, construction phase and operational phase.
5.2 Baseline Model Runs
5.2.1.1 The baseline scenario represents the case without the project and is to provide background conditions for comparison with the water quality conditions in the operational phase of the Project so as to evaluate the potential impacts. As such, the year of simulation for the baseline scenario is 2025 and is the same as the year to be adopted in the operational phase model runs.
5.2.1.2 Hydrodynamic and water quality computations using the Western and Eastern Models were carried out to obtain the baseline conditions. There will be no wastewater discharges or release of contaminants from filling activities at the locations of the potential new waste disposal sites over the entire simulation period. The discharges to be included in the water quality simulation will be from the existing outfalls, stormdrains, nullahs and rivers. At this stage, it is difficult to estimate the changes in pollution loads, which enter the Hong Kong waters, after 20 years or more. In addition, the water quality impact assessment for this study is to compare the cases with and without the Project and there would be no discharge from the project site. It is, therefore, proposed that the pollution loading to be adopted in the baseline model runs will be based on the pollution load inventory compiled under the “Review of North District and Tolo Harbour Sewerage Master Plans” for year 2016. Reference was also made to the pollution load inventory derived under “Update on Cumulative Water Quality and Hydrological Effect of Coastal Development and Upgrading of Assessment Tool”.
5.2.1.3 Model results to be obtained from the baseline model runs include: • Momentary and accumulated flows through East Lamma Channel, Tathong Channel and West Lamma Channel for the Western Model as well as Tolo Channel, Mirs Bay and Tathong Channel for the Eastern Model; and • Water quality conditions including the parameters of 90%ile depth-averaged dissolved oxygen (DO), 90%ile bottom DO, depth-averaged salinity, depth- averaged total inorganic nitrogen (TIN), depth-averaged unionized ammonia (UIA), depth-averaged SS, and depth-averaged E.coli.
5.3 Construction Phase Model Runs
5.3.1.1 The potential water quality impacts that may arise during the construction phase of the Project would be the release of fines and sediment particles from the filling and dredging activities. Sediment plume modelling will be conducted to predict the dispersion of sediment and the increases in SS levels in the surrounding waters.
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5.3.1.2 The hydrodynamic conditions to be generated using the two detailed models for hydrodynamic computations will be used for the sediment plume modelling. The processes of settling of sediment particles and exchange of sediment particles between the water column and the seabed govern the sediment transport. Sediment deposition and erosion would occur when the bed shear stress is below or above the critical shear stress. The deposition rate and erosion rate were calculated using the following equations:
(1) Bed Shear Stress (τ) < Critical Shear Stress for Deposition (τd = 0.05 Pascal) Deposition rate = Vs Cb (1 - τ / τd)
Where: Vs = settling velocity (= 0.1mm/s); and Cb = bottom layer SS concentration
(2) Bed Shear Stress (τ) > Critical Shear Stress for Erosion (τe = 0.15 Pascal) Erosion rate = Re (τ / τe – 1)
2 Where: Re = erosion coefficient (= 0.0002 kg/m /s).
5.3.1.3 The sediment loss rate is the key factor affecting the water quality conditions in the surrounding waters. The fine content of C&D materials may vary in a wide range and would be up to 40%. The fine content of sediment would be lower when compared to the C&D materials. As the fill materials include both the C&D materials and uncontaminated sediment. A higher value of fine content of 30% is assumed to determine the sediment loss rate.
5.3.1.4 It is assumed that bottom dumping dredger with a capacity of 2,000m3 would be used to carry out the filling. Filling is assumed to be a 3-minute per 2.5-hour cycle. The allowable working hour would be from 7 a.m. to 7 p.m. with a total of 12 working hours each day for the filling activities. There would be 6 working days per week. The maximum weekly rate of production is therefore calculated to be approximately 57,600m3 (=2,000m3 x 12hr/day ÷ 2.5hr x 6day/week). The estimated loss rate is calculated assuming that the bulk density of the fill materials is 2,000 kg/m3 and the total quantity of fines that will be lost to suspension is 5%. Given a fine content of 30% for C&D materials as discussed above, the estimated loss rate for a release duration of 3 minutes would therefore be 333 kg/s.
5.3.1.5 The artificial island will be formed in a series of approximately 50 hectare cells of a regular shape and seawalls protection will be constructed for the cells. It is proposed that dredging will not be carried out during the reclamation process. However, for a number of sites in the unsheltered area where the seawalls are exposed to considerable wind and wave action, a dredged foundation trench may be required to ensure adequate stability. In order to take a ‘worst case’ approach, it is assumed that dredging for seawall formation be carried out at the following sites:
• Western Sites: M4 to M6 and M12
• All Eastern Sites: M7 to M10
5.3.1.6 It is assumed that Trailing Suction Hopper Dredgers (TSHD) are utilized for dredging. The operation of dredging is assumed to be continuous (i.e. 7 days per week and 24 hours per day). The sediment loss rate during dredging for the TSHD is assumed to
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be 7kg/m3. Thus, the sediment loss rate in unit time would equal to the product of the dredging rate and the sediment loss rate (7kg/m3) for TSHD. Table 5.1 summarised for each site the sediment loss rates that were adopted in the sediment plume model as well as the volume of dredged mud, dredging duration and the corresponding dredging rates.
Table 5.1 Assumed Dredging Rates and Sediment Loss Rates Volume of Dredged Sediment Loss Rate Sites Required Dredging Duration Dredging Rates1 Mud Adopted in Model2 Dredging (month) (m3/s) (x106 m3) (kg/s) Western M4 8 12 0.254 1.78 M5 20 24 0.318 2.23 M6 10 12 0.318 2.23 M12 10 12 0.318 2.23 Eastern M7 4 6 0.254 1.78 M8 25 36 0.265 1.85 M9 15 24 0.238 1.67 M10 15 24 0.238 1.67 Note 1. Dredging Rates = Volume of Dredged Mud / (Dredging Duration/12x52x7x86400) 2. Sediment Loss Rate [kg/s] = Dredging Rate [m3/s] x 7 [kg/m3]
5.3.1.7 The seawall formation and the subsequent dredging activities will be taken place concurrent with the filling activities. In the model, discharge points representing dredging activities were situated where the foundation trenches are most likely be constructed. Meanwhile, in order to model the worse case scenario, the discharge locations for the filling activities of the construction phases are placed closest to the sensitive receivers or shoreline. Figure 4.3 shows the locations of the dredging and filling discharge points modelled in the water quality scenarios.
5.3.1.8 The modelling scenarios for the construction phase include:
Phase Description Dredging/Filling Construction At the early stage of the Project Assumed both dredging Phase 1: when the filling activities begin and filling activities will be carried out Construction At approximately mid-stage of the Assumed both dredging Phase 2: Project where half of the proposed and filling activities will island (in size) have been be carried out constructed Construction At the closing stage of the Project Assumed only filling Phase 3: where the island reaches its activities will be carried proposed size. out.
5.3.1.9 It is assumed that dredging activities will be carried out during Construction Phase 1 and 2 only while filling activities will be carried throughout the 3 construction phases.
5.3.1.10 The year of simulation for the Construction Phase 1 model runs will be 2007. The sediment loss will be evenly distributed in the vertical water column of a grid cell, which represents the filling location. In general, tidal current speeds are higher near the water surface. The sediment particles in the upper layer take a longer time to settle onto the seabed than the sediment particles in the lower layer.
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5.3.1.11 After a prolonged period of filling, the artificial island will be created at the filling location and it may affect the tidal flows in the area near the island. For Construction Phases 2 and 3, the dispersion of sediment will be influenced by the presence of the artificial island. It is assumed that Construction Phase 2 would exist between 2011 and 2016. The coastline configurations for this case would be the same as the operational phase. The sediment loss will be evenly distributed in the vertical water column from the submerged ground surface at the filling location to the water surface. Figure 4.4 shows the configuration of Construction Phase 2.
5.3.1.12 For the Construction Phase 3 model runs, hydrodynamic data for year 2025 with the artificial island in place were used for the sediment plume modelling. All the sediment loss was allocated into the upper layer of the grid cell in the immediate vicinity of the artificial island. Appropriate coastline configurations for various construction phase simulations were adopted.
5.3.1.13 The sediment plume modelling results are compared with the Water Quality Objective for SS at the nearby water quality sensitive receivers to check for compliance. The daily sedimentation rates at the coral sites near the potential filling locations/artificial islands are presented.
5.4 Operational Phase Model Runs
5.4.1.1 The expected completion date for this Project is in 2025. The presence of the artificial island may affect the hydrodynamic and water quality conditions in the surrounding waters and may affect the flushing capacity through the major channels.
5.4.1.2 During the model setup, sections at the major channels including East Lamma Channel, Tathong Channel and West Lamma Channel for the Western Model as well as Tolo Channel, Mirs Bay and Tathong Channel for the Eastern Model were defined to calculate the inflow and outflow through these channels during the hydrodynamic simulation. The Western and Eastern Models produced both the accumulated flow and momentary flow through these major channels. Comparisons between the baseline conditions and the operational phase conditions were made to assess whether there would be any effects on the exchange of flow through these major channels.
5.4.1.3 For the water quality simulation, the pollution loading adopted in the operational phase model runs are based on the pollution load inventory compiled under the “Review of North District and Tolo Harbour Sewerage Master Plans” for year 2016. The predicted water quality conditions at the sensitive receivers and EPD marine water sampling stations near the artificial island were assessed. The water quality parameters to be assessed will include 90%ile depth-averaged dissolved oxygen (DO), 90%ile bottom DO, depth-averaged salinity, depth-averaged total inorganic nitrogen (TIN), depth-averaged unionized ammonia (UIA), depth-averaged SS, and depth- averaged E.coli. Comparisons of the operational phase conditions with the baseline conditions and the relevant WQOs were also made.
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APPENDIX A: Additional Flow Analysis
This section provides supplementary information on the effect of flow via major channels due to the presence of Sites M1 (Deep Bay), M2 (Sha Chau), M5 (South Cheung Chau) and M6 (Lamma Breakwater). The relative changes of tidal flow through major channels due to the presence of the proposed island were calculated for the following tide phases:
• Wet season spring flood phase • Wet season spring ebb phase • Wet season neap flood phase • Wet season neap ebb phase • Dry season spring flood phase • Dry season spring ebb phase • Dry season neap flood phase • Dry season neap ebb phase
For each particular site, the relative differences in tidal flux are compared between different major channels. Based on the review of the flow data, it was found that the presence of the island would not induce any phase shift in tidal flow at a same channel. However, the tidal flow would experience minor phase shift spatially across different channels. Based on the review of momentary flow and water level data at different channels, the time periods chosen for different tide phases for different channels were adjusted to take into account such minor phase change and to make sure that the tidal elevations for different channels that are using for the comparison are exactly in phase.
Site M2 From Table 1, it can be seen that the presence of Site M2 would result in small reduction (<3%) in the calculated fluxes across Tai Lam Channel during dry season: at spring ebb and neap flood periods; and wet season: at spring flood, neap flood and neap ebb periods. During all the remaining tide phases, there would be minimal increases in the tidal fluxes across the channel (<0.2%).
This means that the presence of the M2 island will have a general minor reduction of flow through the harbour west area. Consequently, the pollution dispersion capacity of the harbour west area will be slightly reduced.
Site M5 Table 2 presents the predicted accumulated fluxes across Victoria Harbour Channel, East Lamma Channel, West Lamma Channel and Adamasta Channel. Figure 1 shows the locations of these major channels.
Victoria Harbour The presence of Site M5 would cause a small reduction in the accumulated fluxes during wet season neap ebb and neap flood periods (-0.91% and -1.44% respectively). Changes in the tidal fluxes were minimal during all the other remaining tide phases (ranged from 0.00% to + 0.41%).
East Lamma Channel Again, the presence of Site M5 would cause a small reduction in the accumulated fluxes during wet season neap ebb and neap flood periods (-1.34% and -0.52% respectively). There would be small increases in the accumulated fluxes at all the remaining tide phases (ranged from +0.05% to +1.17%)
West Lamma Channel The presence of Site M5 would cause moderate impact on the tidal fluxes during dry season (changes of –5.38% to +14.76% were predicted by the model). There would be small increases (ranged from +0.58% to +2.53%) in accumulated fluxes during wet season at all tide phases except only for spring flood period where a small reduction (-3.77%) in the calculated fluxes was predicted by the model.
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Adamasta Channel The effect on Adamasta Channel is moderate during dry season (changes of –14.66% to 0.00% were predicted by the model. The effect is however considered quite large during the wet season. There would be a large reduction in the calculated fluxes during wet season spring ebb and neap ebb periods (-24.40% and –62.64%) respectively. During wet season spring flood and neap flood periods, the effects were predicted to be relatively smaller (+11.6% and 0.94% respectively).
Overall Effect The effect on the overall changes in flow discharges through these four channels is however small. The net reductions are within 2% (average change is negligible). This relatively small change in flow indicating that the dispersion capability of harbour west area has not been changed by the presence of the island M5. However, the flow has been redistributed to from Adamasta Channel to the other channels. West Lamma Channel received the least share of redistribution.
Site M6 Table 3 presents the predicted accumulated fluxes across Victoria Harbour Channel, East Lamma Channel, West Lamma Channel and Adamasta Channel. Figure 1 shows the locations of these major channels.
Victoria Harbour The presence of Site M6 would cause a small increase in the accumulated fluxes (ranged from 0.96% to 2.74%) at all tide phases except for during wet season neap flood period where there would be a small reduction in the calculated fluxes (-3.02%).
East Lamma Channel The proposed island would increase the accumulated fluxes at all tide phases (ranged from 1.08% to 7.25%).
West Lamma Channel The proposed island would reduce the accumulated fluxes at all tide phases (ranged from -4.87% to - 9.66%).
Adamasta Channel
The effect on Adamasta Channel is considered quite large. The model predicted that there would be increases in the tidal fluxes through the channel at all tide phases (ranged from +6.05% to +89.66%).
Overall Effect It is considered that the presence of the proposed island would in general reduce the fluxes through West Lamma Channel and redistributed to the remaining three channels. East Lamma Channel receives the largest share of the West Lamma Channel flow. The effect on the overall changes in the flow discharges through the four channels is however small. The net reductions are within 1% (average change is less than 0.5%). Therefore, the pollutant dispersion capability of harbour west area has only been marginally reduced.
Site M1 The results for accumulated total discharges through inner Deep Bay and outer Deep Bay were analyzed. Table 4 shows the changes in the predicted fluxes due to Site M1. Figure 2 shows the locations of the cross sections used. The island would be located in between the inner and outer Deep Bay cross sections. It was predicted that Site M1 would reduce the fluxes through both inner and outer Deep Bay Channels with a considerably higher relative reduction (ranged from -5.37% to -7.02%) at the outer Deep Bay as compared to the inner Deep Bay (ranged from +0.06% to -2.08%). It is believed that the proposed island would reduce the flushing capacity of Deep Bay. The pollutant levels within Deep Bay would potentially be increased as more pollutant (discharged from the Deep Bay catchments) would tend to accumulate inside the bay due to the reduction in the flushing capacity. This can be further supported by the changes in salinity levels at the stations within the inner Deep Bay. The model predicted that the salinity levels would be decreased in the inner Deep Bay due to the proposed island suggesting that more freshwater (and thus
C:\Documents and Settings\chahyc.000\My Documents\98347\wqm\App A - add flow_v2.doc A-2 Hydrodynamic and Water Quality Modelling Services For Potential New Waste Disposal Sites – Final Water Quality and Hydrodynamic Assessment Report more pollutants) discharged from the rivers flowing into the inner Deep Bay would be accumulated inside the bay.
The apparent reduction in nutrient levels is due to the fact that a very conservative pollution loading (for year 1998) was adopted for Pearl River discharges whilst a less conservative scenario (for year 2016) was adopted for the pollution discharged from the Deep Bay catchments. Under the baseline scenario (without the island), the model predicted that a significant amount of nutrients from Pearl River would be washed into the Deep Bay. The presence of Site M1 would reduce the tidal flows into Deep Bay and thus blocking part of the nutrients from entering the Deep Bay. Although the water quality modelling revealed that there would be an improvement in the nutrient levels inside the Deep Bay, it is considered that Site M1 is not a preferred site in terms of water quality impact due to the fact that the proposed island would potentially reduce the self-cleansing capacity of Deep Bay, and there are uncertainties about the future pollution loading discharged into Deep Bay, especially a portion of the pollutants loadings is from Shenzhen, which is not under the control of HKSAR Government, (i.e. the future pollution loading from Pearl River would likely be smaller than that currently adopted in the model while the future pollution loading discharged from the Deep Bay catchments may not be as low as currently predicted).
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Figure 1 Location of Major Channels
Tai Lam Channel
Victoria Harbour Channel
Adamasta Channel
East Lamma Channel
West Lamma Channel
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Figure 2 Locations of Deep Bay Channels
Inner Deep Bay
Outer Deep Bay
C:\Documents and Settings\chahyc.000\My Documents\98347\wqm\App A - add flow_v2.doc A-5 Table 1 Changes in Accumulated Flow at Tai Lam Channel Due to Site M2
Table 1 Tai Lam Accumulated Flow (m3) Baseline Scenario Operational Scenario Difference Relative Difference Dry Season Spring Tide Flood Phase 2/11/2025 16:00 -7.04712E+08 -7.14612E+08 2/11/2025 22:15 -1.30291E+09 -1.31381E+09 Difference -5.98200E+08 -5.99200E+08 -1.00E+06 0.17%
Ebb Phase 2/11/2025 22:30 -1.30041E+09 -1.31141E+09 2/12/2025 5:45 -3.86882E+08 -3.98421E+08 Difference 9.13530E+08 9.12991E+08 -5.39E+05 -0.06%
Neap Tide Flood Phase 2/18/2025 7:45 -1.28259E+09 -1.23019E+09 2/18/2025 14:00 -1.77559E+09 -1.70999E+09 Difference -4.93000E+08 -4.79800E+08 1.32E+07 -2.68%
Ebb Phase 2/18/2025 15:00 -1.76279E+09 -1.69679E+09 2/18/2025 19:45 -1.41549E+09 -1.34919E+09 Difference 3.47300E+08 3.47600E+08 3.00E+05 0.09% Wet Season Spring Tide Flood Phase 7/26/2025 5:00 1.42E+07 1.47E+07 7/26/2025 10:30 -5.92E+08 -5.83E+08 Difference -6.06E+08 -5.97E+08 8.90E+06 -1.47%
Ebb Phase 7/26/2025 11:15 -6.07E+08 -5.97E+08 7/26/2025 18:45 3.91E+08 4.01E+08 Difference 9.98E+08 9.99E+08 1.20E+06 0.12%
Neap Tide Flood Phase 7/31/2025 20:00 -1.51E+08 -6.21E+07 8/1/2025 3:00 -6.22E+08 -5.25E+08 Difference -4.71E+08 -4.62E+08 8.50E+06 -1.81%
Ebb Phase 8/1/2025 3:30 -6.17E+08 -5.20E+08 8/1/2025 8:15 -3.31E+08 -2.37E+08 Difference 2.86E+08 2.83E+08 -3.22E+06 -1.12%
Convention : -ve means flow leaving the control voulme bounded by Victoria Harbour, East & West Lamma, Adamasta and Tai Lam Channel. Table 2 Changes in Accumulated Flow through Major Channels Due to Site M5
Table 2 Victoria Harbour East Lamma Channel West Lamma Channel Adamasta Channel Overall Changes Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Baseline Operational Relative Baseline Relative Baseline Operational Baseline Operational Relative Baseline Relative Scenario Scenario Difference Difference Scenario Operational Scenario Difference Difference Scenario Scenario Difference Relative Difference Scenario Scenario Difference Difference Scenario Operational ScenarioDifference Difference Dry Season Spring Tide Flood Phase 2/11/2025 16:00 8.33E+08 8.32E+08 -3.10E+09 -3.10E+09 2.43E+09 2.47E+09 3.21E+08 2.75E+08 2/11/2025 21:30 9.26E+08 9.26E+08 -2.81E+09 -2.81E+09 2.75E+09 2.79E+09 3.52E+08 3.06E+08 Difference 9.36E+07 9.37E+07 1.00E+05 0.11% 2.88E+08 2.89E+08 1.00E+06 0.35% 3.21E+08 3.21E+08 0.00E+00 0.00% 3.05E+07 3.05E+07 0.00E+00 0.00% 7.34E+08 7.35E+08 1.10E+06 0.15%
Ebb Phase 2/11/2025 22:00 9.25E+08 9.25E+08 -2.81E+09 -2.81E+09 2.74E+09 2.76E+09 3.55E+08 3.09E+08 2/12/2025 4:15 8.16E+08 8.16E+08 -3.38E+09 -3.38E+09 2.30E+09 2.34E+09 3.16E+08 2.69E+08 Difference -1.09E+08 -1.09E+08 -2.00E+05 0.18% -5.72E+08 -5.73E+08 -1.00E+06 0.17% -4.44E+08 -4.20E+08 2.39E+07 -5.38% -3.96E+07 -3.96E+07 0.00E+00 0.00% -1.17E+09 -1.14E+09 2.27E+07 -1.95%
Neap Tide Flood Phase 2/18/2025 7:45 1.33E+09 1.33E+09 -3.44E+09 -3.44E+09 2.82E+09 2.85E+09 2.52E+08 2.06E+08 2/18/2025 13:30 1.42E+09 1.41E+09 -3.15E+09 -3.15E+09 3.04E+09 3.07E+09 2.62E+08 2.15E+08 Difference 8.90E+07 8.90E+07 0.00E+00 0.00% 2.89E+08 2.89E+08 1.50E+05 0.05% 2.20E+08 2.20E+08 0.00E+00 0.00% 9.81E+06 9.81E+06 0.00E+00 0.00% 6.08E+08 6.08E+08 1.50E+05 0.02%
Ebb Phase 2/18/2025 14:00 1.41E+09 1.41E+09 -3.15E+09 -3.15E+09 2.98E+09 3.04E+09 3.18E+08 2.61E+08 2/18/2025 19:00 1.36E+09 1.36E+09 -3.34E+09 -3.35E+09 2.85E+09 2.89E+09 2.43E+08 1.96E+08 Difference -5.12E+07 -5.12E+07 0.00E+00 0.00% -1.95E+08 -1.96E+08 -6.00E+05 0.31% -1.33E+08 -1.52E+08 -1.96E+07 14.76% -7.57E+07 -6.46E+07 1.11E+07 -14.66% -4.55E+08 -4.64E+08 -9.10E+06 2.00% Wet Season Spring Tide Flood Phase 7/26/2025 4:45 3.92E+07 3.93E+07 1.63E+09 1.63E+09 -2.12E+09 -2.12E+09 5.75E+08 5.77E+08 7/26/2025 9:45 1.10E+08 1.10E+08 2.02E+09 2.03E+09 -1.84E+09 -1.85E+09 6.33E+08 6.41E+08 Difference 7.06E+07 7.09E+07 2.64E+05 0.37% 3.93E+08 3.98E+08 4.60E+06 1.17% 2.79E+08 2.68E+08 -1.05E+07 -3.77% 5.74E+07 6.40E+07 6.65E+06 11.60% 8.00E+08 8.01E+08 1.01E+06 0.13%
Ebb Phase 7/26/2025 11:00 9.99E+07 1.00E+08 2.04E+09 2.04E+09 -1.81E+09 -1.83E+09 6.32E+08 6.42E+08 7/26/2025 16:30 -2.58E+07 -2.59E+07 1.54E+09 1.54E+09 -2.38E+09 -2.40E+09 6.15E+08 6.29E+08 Difference -1.26E+08 -1.26E+08 -5.10E+05 0.41% -4.95E+08 -5.00E+08 -5.12E+06 1.03% -5.69E+08 -5.72E+08 -3.30E+06 0.58% -1.68E+07 -1.27E+07 4.10E+06 -24.40% -1.21E+09 -1.21E+09 -4.83E+06 0.40%
Neap Tide Flood Phase 7/31/2025 8:30 1.05E+08 9.93E+07 3.22E+09 3.21E+09 -4.12E+09 -4.21E+09 1.03E+09 1.11E+09 7/31/2025 13:15 1.65E+08 1.59E+08 3.49E+09 3.48E+09 -3.98E+09 -4.07E+09 1.07E+09 1.15E+09 Difference 6.02E+07 5.94E+07 -8.70E+05 -1.44% 2.71E+08 2.69E+08 -1.42E+06 -0.52% 1.45E+08 1.46E+08 1.62E+06 1.12% 3.62E+07 3.65E+07 3.40E+05 0.94% 5.12E+08 5.11E+08 -3.30E+05 -0.06%
Ebb Phase 7/31/2025 14:00 1.62E+08 1.55E+08 3.50E+09 3.49E+09 -3.97E+09 -4.06E+09 1.07E+09 1.15E+09 7/31/2025 18:15 9.74E+07 9.15E+07 3.34E+09 3.33E+09 -4.15E+09 -4.25E+09 1.07E+09 1.15E+09 Difference -6.45E+07 -6.39E+07 5.90E+05 -0.91% -1.58E+08 -1.56E+08 2.11E+06 -1.34% -1.84E+08 -1.88E+08 -4.65E+06 2.53% -1.74E+06 -6.50E+05 1.09E+06 -62.64% -4.08E+08 -4.09E+08 -8.60E+05 0.21%
Convention : -ve means flow leaving the control voulme bounded by Victoria Harbour, East & West Lamma, Adamasta and Tai Lam Channel.
Dry Spring Dry Neap Wet Spring Wet Neap Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour 0.11% 0.00% 0.37% -1.44% Flood Western Harbour Flood Western Harbour Flood Western Harbour Flood Western Harbour Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) 0.15% 0.02% 0.13% -0.06% Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma 0.00% 0.35% 0.00% 0.05% 11.60% 1.17% 0.94% -0.52%
W , Lamma W , Lamma W , Lamma W , Lamma 0.00% 0.00% -3.77% 1.12%
Dry Spring Dry Neap Wet Spring Wet Neap Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour 0.18% 0.00% 0.41% -0.91% Ebb Western Harbour Ebb Western Harbour Ebb Western Harbour Ebb Western Harbour Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) -1.95% 2.00% 0.40% 0.21% Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma 0.00% 0.17% -14.66% 0.31% -24.40% 1.03% -62.64% -1.34%
W , Lamma W , Lamma W , Lamma W , Lamma -5.38% 14.76% 0.58% 2.53% Table 3 Changes in Accumulated Flow through Major Channels Due to Site M6
Table 3 Victoria Harbour East Lamma Channel West Lamma Channel Adamasta Channel Overall Changes Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Accumulated Flow (m3) Baseline Relative Baseline Relative Baseline Operational Baseline Operational Relative Baseline Relative Scenario Operational Scenario Difference Difference Scenario Operational Scenario Difference Difference Scenario Scenario Difference Relative Difference Scenario Scenario Difference Difference Scenario Operational Scenario Difference Difference Dry Season Spring Tide Flood Phase 2/11/2025 15:45 8.33E+08 8.33E+08 -3.10E+09 -3.03E+09 2.42E+09 2.35E+09 3.33E+08 3.43E+08 2/11/2025 19:00 9.26E+08 9.27E+08 -2.81E+09 -2.72E+09 2.74E+09 2.64E+09 3.68E+08 3.81E+08 Difference 9.36E+07 9.45E+07 9.00E+05 0.96% 2.88E+08 3.09E+08 2.09E+07 7.25% 3.18E+08 2.93E+08 -2.49E+07 -7.83% 3.45E+07 3.78E+07 3.31E+06 9.60% 7.34E+08 7.35E+08 2.10E+05 0.03%
Ebb Phase 2/11/2025 22:00 9.25E+08 9.26E+08 -2.81E+09 -2.72E+09 2.74E+09 2.65E+09 3.71E+08 3.84E+08 2/12/2025 2:15 8.16E+08 8.15E+08 -3.38E+09 -3.31E+09 2.29E+09 2.21E+09 3.29E+08 3.38E+08 Difference -1.09E+08 -1.11E+08 -1.80E+06 1.65% -5.72E+08 -5.86E+08 -1.40E+07 2.45% -4.55E+08 -4.33E+08 2.28E+07 -5.01% -4.22E+07 -4.54E+07 -3.21E+06 7.61% -1.18E+09 -1.18E+09 3.79E+06 -0.32%
Neap Tide Flood Phase 2/18/2025 7:30 1.33E+09 1.33E+09 -3.44E+09 -3.21E+09 2.76E+09 2.52E+09 3.07E+08 3.46E+08 2/18/2025 10:15 1.42E+09 1.42E+09 -3.15E+09 -2.91E+09 2.98E+09 2.72E+09 3.19E+08 3.59E+08 Difference 8.90E+07 9.01E+07 1.10E+06 1.24% 2.89E+08 3.03E+08 1.43E+07 4.95% 2.16E+08 1.96E+08 -1.96E+07 -9.09% 1.19E+07 1.35E+07 1.63E+06 13.71% 6.06E+08 6.03E+08 -2.61E+06 -0.43%
Ebb Phase 2/18/2025 14:00 1.41E+09 1.41E+09 -3.15E+09 -2.91E+09 2.98E+09 2.72E+09 3.18E+08 3.58E+08 2/18/2025 17:15 1.36E+09 1.36E+09 -3.34E+09 -3.11E+09 2.79E+09 2.54E+09 2.99E+08 3.38E+08 Difference -5.12E+07 -5.22E+07 -1.00E+06 1.95% -1.95E+08 -2.01E+08 -5.20E+06 2.66% -1.89E+08 -1.80E+08 9.21E+06 -4.87% -1.92E+07 -2.06E+07 -1.39E+06 7.24% -4.55E+08 -4.53E+08 1.62E+06 -0.36% Wet Season Spring Tide Flood Phase 7/26/2025 4:30 3.92E+07 3.90E+07 1.63E+09 1.63E+09 -2.12E+09 -2.12E+09 5.75E+08 5.75E+08 7/26/2025 8:30 1.10E+08 1.11E+08 2.02E+09 2.04E+09 -1.84E+09 -1.87E+09 6.33E+08 6.36E+08 Difference 7.06E+07 7.17E+07 1.09E+06 1.55% 3.93E+08 4.12E+08 1.91E+07 4.86% 2.79E+08 2.52E+08 -2.63E+07 -9.44% 5.74E+07 6.04E+07 3.05E+06 5.32% 8.00E+08 7.97E+08 -3.06E+06 -0.38%
Ebb Phase 7/26/2025 10:45 9.99E+07 1.01E+08 2.04E+09 2.06E+09 -1.81E+09 -1.84E+09 6.32E+08 6.34E+08 7/26/2025 16:00 -2.58E+07 -2.79E+07 1.54E+09 1.54E+09 -2.38E+09 -2.37E+09 6.15E+08 6.12E+08 Difference -1.26E+08 -1.28E+08 -2.79E+06 2.22% -4.95E+08 -5.17E+08 -2.24E+07 4.53% -5.69E+08 -5.31E+08 3.81E+07 -6.69% -1.68E+07 -2.22E+07 -5.40E+06 32.14% -1.21E+09 -1.20E+09 7.51E+06 -0.62%
Neap Tide Flood Phase 7/31/2025 20:30 1.05E+08 9.31E+07 3.22E+09 3.16E+09 -4.12E+09 -3.98E+09 1.03E+09 9.92E+08 8/1/2025 0:45 1.65E+08 1.52E+08 3.49E+09 3.43E+09 -3.98E+09 -3.84E+09 1.07E+09 1.03E+09 Difference 6.02E+07 5.84E+07 -1.82E+06 -3.02% 2.71E+08 2.74E+08 2.91E+06 1.08% 1.45E+08 1.37E+08 -7.45E+06 -5.15% 3.62E+07 3.84E+07 2.19E+06 6.05% 5.12E+08 5.07E+08 -4.17E+06 -0.82%
Ebb Phase 8/1/2025 3:30 1.62E+08 1.48E+08 3.50E+09 3.44E+09 -3.97E+09 -3.84E+09 1.07E+09 1.03E+09 8/1/2025 6:00 9.74E+07 8.18E+07 3.34E+09 3.27E+09 -4.15E+09 -4.00E+09 1.07E+09 1.03E+09 Difference -6.45E+07 -6.63E+07 -1.77E+06 2.74% -1.58E+08 -1.69E+08 -1.11E+07 7.07% -1.84E+08 -1.66E+08 1.78E+07 -9.66% -1.74E+06 -3.30E+06 -1.56E+06 89.66% -4.08E+08 -4.04E+08 3.29E+06 -0.81%
Convention : -ve means flow leaving the control voulme bounded by Victoria Harbour, East & West Lamma, Adamasta and Tai Lam Channel.
Dry Spring Dry Neap Wet Spring Wet Neap Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour 0.96% 1.24% 1.55% -3.02% Flood Western Harbour Flood Western Harbour Flood Western Harbour Flood Western Harbour Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) 0.03% -0.43% -0.38% -0.82% Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma 9.60% 7.25% 13.71% 4.95% 5.32% 4.86% 6.05% 1.08%
W , Lamma W , Lamma W , Lamma W , Lamma -7.83% -9.09% -9.44% -5.15%
Dry Spring Dry Neap Wet Spring Wet Neap Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour Tai Lam Victoria Harbour 1.65% 1.95% 2.22% 2.74% Ebb Western Harbour Ebb Western Harbour Ebb Western Harbour Ebb Western Harbour Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) Total (no Tai Lam) -0.32% -0.36% -0.62% -0.81% Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma Adamasta E. Lamma 7.61% 2.45% 7.24% 2.66% 32.14% 4.53% 89.66% 7.07%
W , Lamma W , Lamma W , Lamma W , Lamma -5.01% -4.87% -6.69% -9.66% Table 4 Changes in Accumulated Flow through Deep Bay Due to Site M1
Table 4 Inner Deep Bay Outer Deep Bay Accumulated Flow (m3) Accumulated Flow (m3) Baseline Operational Relative Baseline Operational Relative Scenario Scenario Difference Difference Scenario Scenario Difference Difference Dry Season Spring Tide Flood Phase 2/11/2025 16:15 1.55E+07 1.50E+07 -2.01E+07 -1.91E+07 2/11/2025 19:00 4.54E+07 4.43E+07 6.06E+07 5.59E+07 Difference 2.99E+07 2.92E+07 -6.20E+05 -2.08% 8.07E+07 7.50E+07 -5.66E+06 -7.02%
Ebb Phase 2/11/2025 22:00 6.95E+07 6.93E+07 1.20E+08 1.13E+08 2/12/2025 2:15 2.00E+07 2.00E+07 -2.51E+07 -2.16E+07 Difference -4.95E+07 -4.93E+07 1.81E+05 -0.37% -1.45E+08 -1.35E+08 9.67E+06 -6.68%
Neap Tide Flood Phase 2/18/2025 8:00 1.58E+07 1.39E+07 -6.13E+07 -5.82E+07 2/18/2025 10:45 3.90E+07 3.71E+07 7.27E+06 6.12E+06 Difference 2.33E+07 2.32E+07 -4.40E+04 -0.19% 6.86E+07 6.43E+07 -4.21E+06 -6.14%
Ebb Phase 2/18/2025 14:00 5.78E+07 5.69E+07 5.06E+07 4.89E+07 2/18/2025 19:30 3.70E+07 3.59E+07 -9.23E+06 -7.73E+06 Difference -2.08E+07 -2.09E+07 -1.85E+05 0.89% -5.98E+07 -5.66E+07 3.21E+06 -5.37% Wet Season Spring Tide Flood Phase 7/26/2025 5:30 -1.76E+07 -1.80E+07 7.12E+06 6.80E+06 7/26/2025 8:30 2.11E+07 2.00E+07 1.15E+08 1.07E+08 Difference 3.87E+07 3.80E+07 -6.90E+05 -1.78% 1.07E+08 1.00E+08 -7.46E+06 -6.95%
Ebb Phase 7/26/2025 10:45 4.68E+07 4.78E+07 1.81E+08 1.73E+08 7/26/2025 16:00 -2.20E+07 -2.07E+07 -1.76E+07 -1.29E+07 Difference -6.88E+07 -6.85E+07 3.13E+05 -0.45% -1.98E+08 -1.86E+08 1.28E+07 -6.43%
Neap Tide Flood Phase 7/31/2025 20:30 -4.70E+07 -4.71E+07 -3.37E+07 -3.20E+07 8/1/2025 0:45 -1.71E+07 -1.72E+07 5.29E+07 4.94E+07 Difference 2.98E+07 2.99E+07 1.70E+04 0.06% 8.66E+07 8.14E+07 -5.12E+06 -5.91%
Ebb Phase 8/1/2025 3:30 -7.72E+06 -7.54E+06 7.65E+07 7.27E+07 8/1/2025 6:00 -2.23E+07 -2.20E+07 3.43E+07 3.34E+07 Difference -1.46E+07 -1.45E+07 1.03E+05 -0.71% -4.22E+07 -3.93E+07 2.92E+06 -6.92%
Convention : -ve means flow leaving Deep Bay Extension of Existing Landfills and Identification Scott Wilson Ltd of Potential New Waste Disposal Sites January 2003
APPENDIX II TECHNICAL NOTE: WENT AND NENT LANDFILL ARCHAEOLOGICAL RELICS (NOVEMBER 2002)
Final SEA Report – Appendix II \enviro\r\98347\FinalSEA\Divider
Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
TABLE OF CONTENTS Page
1.1 INTRODUCTION ...... 2
1.2 WASTE MANAGEMENT IN HONG KONG ...... 2
1.3 PRESERVATION OF ARCHAEOLOGICAL RELICS ...... 3
1.4 ASSESSMENT OF PREFERRED PRESERVATION OPTION ...... 4
1.5 WENT LANDFILL...... 4
1.6 NENT LANDFILL ...... 7
1.7 SUMMARY ...... 11
enviro\r\98347\app ii-amo note II-1 6 November 2002
Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
1.1 Introduction
1.1.1 In order to provide additional landfill capacity in the HKSAR for the disposal of solid waste it has been proposed, amongst other measures, that the existing WENT and NENT Landfills should be extended.
1.1.2 For the WENT site (located near Castle Peak in the West New Territories), two proposed extension areas (WENT A and WENT B) have been identified, both of which are located to the west of the current landfill site. The WENT B Extension site includes the full area of the Tsang Tsui Archaeological Site (TTAS) (see Drawing 305B).
1.1.3 For the NENT site (located near Robin’s Nest in the North West New Territories), an extension to the south-east of the current landfill site has been proposed. The NENT Extension site overlaps the area at Tong To Shan and Ngong Tong, where a previous settlement has been discovered. The NENT Extension site coincides with a small part of the proposed Tong To Shan Archaeological Site and a larger area in Ngong Tong where graves have been identified (see Drawing 116D).
1.1.4 It is planned that construction of both the NENT and WENT Landfill Extensions would start in 2011.
1.2 Waste Management in Hong Kong
1.2.1 A study (CE45/99) has been carried out on behalf of the HKSAR Government to identify the necessary landfill capacity for waste disposal until 2050. This study identified that, assuming that waste-to-energy facilities and other measures to reduce waste are commissioned, the HKSAR needs to provide a total landfill capacity of about 515 M tonnes up to 2050.
1.2.2 A variety of options for providing this capacity were identified as follows:
Remaining capacity in SENT, NENT and WENT Landfills at the end 117 M tonnes of 2001 Landfill Extensions: • NENT B Landfill Extension 21 M tonnes • WENT A Landfill Extension 6 M tonnes • WENT B Landfill Extension 72 M tonnes New Series Landfills: • New land based landfill site at Pillar Point Valley North 72 M tonnes • New marine landfill site at South Cheung Chau 154 M tonnes TOTAL 442 M tonnes SHORTFALL 73 M tonnes
1.2.3 An exhaustive search of the HKSAR has been made and no other land based sites are available. The only way that the shortfall can be made up would be to develop another marine landfill site.
1.2.4 The existing landfills will be exhausted in the coming 10 to 15 years, with SENT by 2009, WENT and NENT by 2013 at the earliest.
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Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
1.2.5 Due to the lead-in time required for consultation, design and, in the case of South Cheung Chau, the construction of the artificial island, the new landfills cannot be commissioned before 2020. There is thus a definite need to extend the capacity of the existing landfills to ensure the availability of landfill capacity until the new series landfills are available. Failure to secure adequate extension of capacity would result in the current capacity being used up before new capacity could be made available, and hence there would be a discontinuity to the essential waste disposal services for the whole community.
1.2.6 To ensure the waste disposal system can be operated in an environmentally acceptable standard, at least two landfills at different locations should be maintained at all time. As there is no extension scheme identified for the SENT Landfill, both the extensions to the WENT and NENT Landfills are indispensable.
1.2.7 Even with the introduction of waste minimisation techniques throughout the HKSAR, the community will continue to generate waste at a similar rate to the present rate. Using current waste generation assumptions, it is estimated that approximately 40 M tonnes will be produced in the 7 year-long discontinuity (between 2013 and 2020). During this period, the HKSAR Government would have to manage this waste in order to avoid illegal fly-tipping. If no capacity is available at suitably engineered waste disposal landfill sites, the Government would be forced to either utilise a less highly engineered site, which is untenable (even if a suitable site could be located), or to provide temporary storage for the waste until such a time as the new series landfill sites are able to start receiving waste. Temporary storage of waste has many inherent problems including:
• The need to identify a suitably large site,
• Environmental issues such as noise, odour, dust, visual impact, hygiene problems in the surrounding area etc. will have to be managed and mitigated,
• Some form of containment system would have to be constructed to retain the waste. This should ideally limit the volume of water entering the waste, and must allow leachate and/or gas to be collected and treated.
• The cost of temporary storage per tonne of waste will be significantly higher than landfilling, due to the volume of temporary works that would be required, the double handling of the waste as it is eventually transferred to the landfill site and the likely remediation that would be required at the temporary storage site once it is no longer required.
1.3 Preservation of Archaeological Relics
1.3.1 The preferred method of preservation of archaeological relics is to preserve them insitu, i.e. to avoid them altogether. This would be done by amending the proposed development scheme so as to exclude the area of the relics from the development area. The costs and benefits of preservation insitu must be weighed against all other material considerations including the relative importance and significance of the relics themselves.
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Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
1.3.2 A further technique for preservation that is sometimes used is preservation insitu by burying the archaeological relics under earthworks or the foundations of structures so that they are preserved undamaged for posterity. In this case care must be taken to ensure that the earthworks (designed to protect the archaeological remains) do not cause damage to the relics, either during construction or due to the load imposed upon them.
1.3.3 Where it is not possible to preserve relics insitu, an acceptable alternative may be to preserve them by relocation, i.e. to arrange for a rescue excavation of the area prior to commencement of construction. During the excavation the archaeological evidence is recorded and the results of the excavation published.
1.4 Assessment of Preferred Preservation Option
1.4.1 For each landfill a number of alternative options were assessed for practicability, feasibility and effectiveness.
1.5 WENT Landfill
Background on Tsang Tsui Archaeological Site (TTAS)
1.5.1 The TTAS was initially identified by the Antiquities and Monuments Office (AMO) of the Leisure and Cultural Services Department in October 2000, during the preliminary feasibility study for a Sludge Treatment facility. Relics dating from the late Neolithic Period (c.2500-1500 B.C) were found at the site.
1.5.2 The TTAS is a recorded item by AMO and is thus protected by the Antiquities and Monuments Ordinance, Cap. 53.
1.5.3 The proposed WENT B Extension to the existing WENT Landfill overlaps the boundary of the TTAS, and thus, to ascertain the archaeological potential of the proposed extension a preliminary archaeological survey, comprising the excavation of 8 test pits together with drilling of 44 auger holes, was carried out between August and September 2001.
1.5.4 The investigation concluded that the construction of the former BBC station, the WENT Landfill and the CLP ash lagoons has left the area very disturbed and that, with the exception of the existing TTAS it was very unlikely that archaeological remains would be found in this area. The Preliminary Archaeological Report on the Proposed Extensions of WENT Landfill at Nim Wan Site, Tuen Mun concluded that no further archaeological survey would be required.
1.5.5 The report on the archaeological investigation proposed that the extension of WENT Landfill should be allowed to go ahead, but that the existing TTAS should not be disturbed and that prior consent from AMO would be necessary for any proposed development within the boundary of the TTAS.
Options
Preservation Insitu by avoiding Archaeological Site
1.5.6 The first option considered was to preserve the TTAS by amending the landfill extension boundary to avoid the area where the relics are located. enviro\r\98347\app ii-amo note II-4 6 November 2002
Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
1.5.7 The TTAS is located near the centre of the WENT B Extension area, in the area where it is likely that the greatest depth of waste would be placed.
1.5.8 Amending the boundary of the landfill extension so as to avoid the TTAS is likely to reduce the capacity of the extension by 41 M tonnes (between half and two-thirds of the proposed volume). As mentioned in Section 1.2 it is predicted that even with the construction of two new landfill sites, and the extension of the existing landfills, there would be a shortfall of approximately 73 M tonnes in the landfill capacity available in Hong Kong until 2050. Loss of capacity of the WENT B Extension would result in the shortfall in capacity increasing to 114 M tonnes.
1.5.9 In addition to the loss of capacity, the unit cost of providing waste disposal capacity (currently assessed to be approximately $50/tonne) is likely to increase as it would not be possible to realise the same economies of scale.
1.5.10 Based on current waste generation rates in Hong Kong, it is likely that if the full capacity of the WENT Extensions cannot be provided, there would be a “gap” in the provision of landfill capacity in the Tuen Mun area. This area will be serving nearly two-thirds of the total waste generated in the HKSAR by that time. The waste which would have been disposed of at the WENT site will have to be diverted to the extended NENT site, but this in turn would cause the NENT site to become filled more quickly, and it’s capacity would be exhausted before the new landfills can be made operational. The implications of this are discussed in Sections 1.2.5 to 1.2.7 with the capacity of all the existing and extension sites becoming exhausted before any new site is available.
1.5.11 The costs of construction for the WENT B Extension and an island landfill are $50 per tonne and $200 per tonne respectively. The additional cost to the Government in compensating the capacity lost at the WENT B site by building another island landfill has been estimated at $6 billion (i.e. 41 M tonnes x ($200-$50)). Besides, the building of another island landfill would shift the environmental impacts of a land-based landfill to a marine-based one with more severe implications.
Preservation Insitu by Burial
1.5.12 The second option considered was to preserve the TTAS insitu, but buried under the landfill. This preservation method is based on the assumption that it would be possible to exhume the relics in the future, if this is desired.
1.5.13 However, as the relics are located within one metre below the ground level, they would be easily damaged during the clearance operation and subsequent site formation to provide a stable foundation for the landfill liner. Also, after burial, the eventual loading imposed by up to 100 metres depth of waste could lead to the relics being damaged insitu.
1.5.14 Besides, any future exhumation of the relics would be difficult, costly and undesirable, as it could compromise the integrity of the landfill liner, and the excavation through large depths of waste would have significant safety, environmental and health concerns.
Preservation by Removal
1.5.15 The third option considered was to remove the relics using rescue excavation techniques before the construction of the landfill. enviro\r\98347\app ii-amo note II-5 6 November 2002
Agreement No. CE 45/99 Extension of Existing Landfills and Identification of Potential New Waste Disposal Sites WENT and NENT Landfill Archaeological Relics
1.5.16 This would involve archaeological recording of the site prior to commencement of the landfill construction. A programme, which would normally include fieldwork, would be set up to collect specified data within given time and cost restraints. The scope of this programme would be agreed with AMO. The end result of the programme would be publications that reflect the significance of the data collected, and the creation of an archive deposited in an appropriate place to allow continuing curation and legitimate access to the artefacts.
1.5.17 This preservation method has the advantages that it would allow the development of the WENT B Extension to continue and at the same time the archaeological relics and findings from the programme could be displayed at a suitable location within the HKSAR as an educational facility that would benefit the community.
Summary
1.5.18 All options were considered to identify the most practical and feasible means.
1.5.19 The following options were considered:
(a) Preservation Insitu by avoiding Archaeological Site:
Because of capacity loss to the landfill and the additional costs of allocating the landfill capacity elsewhere, this option is not considered feasible.
(b) Preservation Insitu by Burial
Because of: • the potential damage to the relics during clearance and site formation, and subsequently by the loading of waste; • the unlikelihood that the landfill would be “mined” in the future; • the difficulty of excavating through a depth of waste, which could be as much as 100 m; and • the associated health/safety issues and environmental risks; this option is not considered feasible.
(c) Preservation by Removal
From a conservation point of view, this is the least attractive of the options because it involves the removal of the relics and the loss of the site for future investigations. Nevertheless as a last resort, recognising the impracticability and non-feasibility of the other options, this is the most practical and feasible option.
It is envisaged that the relics would be put on display at either an existing museum or a dedicated facility/visitors’ centre developed as part of the landfill scheme. Putting the excavated relics on display would enable the public to better appreciate Hong Kong’s varied historical background than if these relics remained buried in the ground.
Alternatively rather than a site specific display of relics in a visitors’ centre, a regional museum facility could be developed to enable the rich and varied archaeological findings along the shoreline of the North West New Territories (TTAS enviro\r\98347\app ii-amo note II-6 6 November 2002
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being one of many archaeological sites along this part of the SAR’s coast) to be put on display and include relics from the numerous archaeological sites along the eastern shoreline of Deep Bay and around Lung Kwu Tan.
1.6 NENT Landfill
Background
1.6.1 A preliminary archaeological survey and assessment of the proposed NENT Landfill site was carried out in August and September 2001. In this survey a “settlement district” dated from the first half of the 17th century to the early 20th century was discovered in the northern part of the area and centred at Tong To Shan. The features identified include 91 stone structural features, mainly distributed in the vicinity of Tong To Shan and 40 graves in the Ngong Tong area to the west of the northern part of the survey area.
1.6.2 The stone structural features comprise buildings (remains of houses and a cistern), slope protection walls and trackways.
1.6.3 The report on the archaeological survey concluded that the Tong To Shan Settlement has great cultural, historical and archaeological significance as it has been well preserved and reflects many aspects of human life in Hong Kong during a period of over 300 years. It was recommended that the site should be protected as much as possible, and that the Tong To Shan area, which was considered to be more important than the Ngong Tong area, should be singled out as the “Tong To Shan Archaeological Site” (TTSAS) and excluded from the area of the proposed NENT Landfill Extension. The report indicated that part of the Ngong Tong area could be used for the proposed landfill project, but that some of the graves, with important historical and cultural significance should be preserved and that other graves should be removed prior to construction.
Options
Preservation Insitu by avoiding Archaeological Site
1.6.4 The first option considered was to preserve the TTSAS by amending the landfill extension boundary to avoid the area where the relics are located.
1.6.5 The TTSAS is located in and adjacent to the central northern part of the NENT Extension area.
1.6.6 In order to minimise the impact on the TTSAS, the initial NENT B Extension has been amended by revising the extension boundary so as to minimise the overlap between the NENT B Extension area and the TTSAS1. The loss of waste filling capacity resulting from this amendment was about 0.4 M tonnes. There is also some cost implication in building steep slopes by reinforced earth techniques than traditional methods. However, this mitigation ensures that the majority of the features at the TTSAS are left insitu, except that some of the graves in the Ngong Tong area and parts of two of the stone paths and one slope protection wall would need to be removed/buried. If the NENT B Extension cannot
1 The initial scheme for NENT B is shown on Drawing 98347/129; with the slopes of the earth embankment on the northern side of the landfill would extend significantly into TTSAS. Drawing 98347/129B illustrates a revised scheme with steepened slopes on the north side of the earth embankment achieved using reinforced earth techniques to avoid much of TTSAS. enviro\r\98347\app ii-amo note II-7 6 November 2002
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be implemented, the waste that would be disposed of at this site (approximately one-third of the total waste generated in Hong Kong by that time) would have to be diverted to the extended WENT site. This would cause the WENT site to become filled more quickly, and it’s capacity would be exhausted before the new landfills can be made operational. The implications of this are discussed in Sections 1.2.5 to 1.2.7.
1.6.7 Further amending the boundary of this site so as to avoid the TTSAS entirely is likely to reduce the capacity of the extension by some 5 M tonnes (approximately one quarter of the capacity of the site). The costs of construction for the NENT B Extension and an island landfill are $110 per tonne and $200 per tonne respectively. The additional cost to the Government in compensating the capacity lost at the NENT B site by building another island landfill has been estimated at $450 million (i.e. 5 M tonnes x ($200-$110)). Besides, the building of another island landfill would shift the environmental impacts of a land- based landfill to a marine-based site with more severe implications.
Preservation Insitu by Burial
1.6.8 The second option considered was to preserve the TTSAS insitu, but buried under the landfill. This preservation method is based on the assumption that it would be possible to exhume the relics in the future, if this is desired.
1.6.9 However, as the relics are situated at the ground level, they would be damaged during the clearance operation and subsequent site formation to provide a stable foundation for the landfill liner.
1.6.10 Besides, any future exhumation of the relics would be difficult, costly and undesirable, as it could compromise the stability of the embankment and integrity of the landfill liner, and the excavation through large depths of soil/waste would have significant safety, environmental and health concerns.
Preservation Insitu by using a Cavern Structure
1.6.11 The third option considered was to preserve the stone paths and stone walls in caverns built into the earth embankment on the north side of the landfill. These caverns would provide access to the stone paths and walls for archaeological investigation and inspection.
1.6.12 The caverns are envisaged as being something similar to a road subway with concrete side walls and a roof soffit. Lighting would be provided, and the height and width of the cavern would be such that small excavation machinery could enter, with an “excavation corridor” on either side of the stone path, enabling archaeological investigations to continue inside the cavern. However, the caverns would be vulnerable to landfill gas accumulation, with the possibility of gas migrating from the waste in the landfill. Appropriate venting and monitoring would be needed before anyone could enter a cavern.
Preservation by Detailed Recording
1.6.13 The fourth option considered was to prepare a detailed record of the stone paths and walls before they were destroyed/covered up by the construction of the landfill extension.
1.6.14 This would involve archaeological recording of the parts of the TTSAS that conflict with the NENT B Extension site prior to commencement of construction. A programme, which would normally include fieldwork, would be set up to collect specified data within given enviro\r\98347\app ii-amo note II-8 6 November 2002
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time and cost restraints. The stone paths and walls would be recorded by photographic, cartographic and video means before being destroyed/covered up by the landfill development. The scope of this programme would be agreed with AMO. The end result of the programme would be publications that reflect the significance of the data collected, and the creation of an archive deposited in an appropriate place to allow continuing curation and legitimate access to the relics.
1.6.15 This preservation method has the advantages that it would allow the development of the full capacity of the NENT B Extension, whilst at the same time preserving the majority of the TTSAS insitu. The archaeological remains that had to be moved for the NENT B Extension to go ahead could be rescued and displayed at a suitable location within the HKSAR as an educational facility that would benefit the community.
1.6.16 As part of the relocation of those remains that fall within the NENT B footprint, the remaining TTSAS area could be improved so that the public could inspect those remains that are preserved insitu. This together with the visitors’ centre could enhance the value of the TTSAS as an educational resource.
Summary
1.6.17 All options were considered to identify the most practical and feasible means.
1.6.18 The following options were considered:
(a) Preservation Insitu by avoiding Archaeological Site
Because of capacity loss to the landfill and the additional costs of allocating this landfill capacity elsewhere, this option is not feasible.
The possibility of allocating the 5 M tonne capacity to other sites has been carefully considered. No further opportunity to transfer this capacity to land based sites can be identified, including the opportunities of increasing the size of the WENT Landfill Extensions.
In this context the following requirements of HKSAR’s landfill strategy for the period up to 2020 were key considerations:
(i) At least two landfills at different locations should be operating at any one time to ensure an acceptable waste disposal service to the HKSAR’s householders, industrialists, commercial operators, contractors etc who are all producing waste, and rely on the Government to provide a seamless service for waste disposal.
(ii) At least one of the two landfills should be a land based site so that in the case of severe weather conditions, at times of monsoons and typhoons there would be an alternative destination for waste if the marine vessels used to serve an island landfill are unable to operate.
(iii) The major landfill extensions at WENT B and NENT B would be indispensable to ensure the continuous provision of a waste disposal service for the HKSAR during the period after the existing landfills are filled to capacity (2014) and enviro\r\98347\app ii-amo note II-9 6 November 2002
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the first of the new landfills (including the island landfill) is available to take waste (2020). It is also necessary to ensure a smooth transition between the existing landfills and their extensions and the new series landfills, and therefore the landfill extensions should continue in operation to at least 2021.
(b) Preservation Insitu by Detailed Recording by Burial
From a conservation point of view this is the least attractive of the options because it involves burying some of the stone paths and walls and the loss of part of the site for future investigations.
For those relics that are buried, it is likely that they would be lost because of: • the potential damage to the relics during clearance and site formation; • the unlikelihood that the landfill would be “mined” in the future; • the difficulty of excavating through the large depth of waste as well as the earth embankment on the north side of the landfill; • the possibility that the excavation could prejudice the stability of the earth embankment; • and the associated health/safety issues and environmental risks.
Nevertheless as a last resort, recognising the impracticability and non-feasibility of the other options, this would be the most practical and feasible option.
For future reference, the stone paths and walls would be recorded by photographic, cartographic and video means before being buried by the landfill development. The end result of the programme would be publications that reflect the significance of the data collected, and the creation of an archive deposited in an appropriate place to allow continuing curation and legitimate access to the relics.
As a further mitigation measure, some of the relics could be excavated and put on display at a dedicated facility/visitors’ centre developed as part of the landfill scheme. Putting the excavated relics on display would enable the public to better appreciate Hong Kong’s varied historical background than if these relics remained buried in the ground.
(c) Preservation Insitu by using a Cavern Structure
By including a cavern structure into the earth embankment on the north side of the landfill, access to the stone paths and walls could be provided for continued archaeological investigation and inspection. However, the existing features and landscape setting of the stone paths would be lost due to the embankment construction. There would also be health and safety concerns about the risk of landfill gas migration into the caverns that could potentially cause an explosion if gas is present in its most critical composition. Nevertheless with careful monitoring, venting and other arrangements for the cavern, the stone paths could be accessed for archaeological and tourism purposes.
This would be a median option: feasible but not cost- effective nor practical.
enviro\r\98347\app ii-amo note II-10 6 November 2002
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In view of the uncertainties in cost-effectiveness, practicality and feasibility of this preservation option, it is recommended that these areas be further investigated under the Feasibility Study and EIA Stage of this Project.
1.7 Summary
1.7.1 The development of the WENT B Extension is critical to ensuring continued waste disposal capacity in the HKSAR until such a time that the new sites at Pillar Point Valley North and South Cheung Chau can be brought into operation. This, together with the cost of the capacity loss caused by preservation of the TTAS insitu ($6 billion) make this preservation option untenable. It is recommended that archaeological recording and a rescue excavation be carried out at this site, the relics removed to an appropriate location and the findings published. The relics could be displayed in a suitable facility to enable them to be used as an educational resource for the HKSAR. Detailed programme and rescue operations can be worked out in the Feasibility Study and EIA Stage.
1.7.2 The NENT B Extension boundary has already been mitigated so as to ensure that most of the relics at the TTSAS can be preserved insitu. Avoidance of the TTSAS entirely would result in a further cost to the Government of $450 million to build another island landfill in compensating for the capacity loss. In addition, the building of another island landfill would shift the environmental impacts of a land-based landfill to a marine-based one with more severe implications. The total removal of the archaeological relics in the overlapping area to allow the NENT B Extension to go ahead is considered the most feasible and practical option. The excavated/rescued relics could be displayed in a suitable facility to enable them to be used as an educational resource for the HKSAR. The building of cavern structures under the earth embankment to protect the stone paths could be an alternative, but it involves many uncertainties in cost-effectiveness, practicality and feasibility that need to be further investigated under the Feasibility Study and EIA Stage.
enviro\r\98347\app ii-amo note II-11 6 November 2002