Proposed Upgrade to Berths 601, 602, 603 and 604 and Associated Deepening of the Ben Schoeman Dock, Port of Cape Town
Draft Environmental Impact Report
Report Prepared for Transnet Limited
Report No 367079/2
February 2007
SRK Consulting BSD Deepening EIR Page i Proposed Upgrade to Berths 601, 602, 603 and 604 and Associated Deepening of the Ben Schoeman Dock, Port of Cape Town
Draft Environmental Impact Report
Transnet Limited
SRK Project Number 367079 SRK Consulting The Administrative Building Albion Spring 183 Main Road Rondebosch 7700 South Africa
Postnet Suite #206 Private Bag X18 Rondebosch 7701 South Africa
Tel: (021) 659-3060 Fax: (021) 685-7105
Sharon Jones, [email protected]
February 2007
Compiled by: Reviewed by:
SRK Consulting Project Consultants Partner
Authors: S. Jones, S. Reuther
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page ii Table of Contents 1 General Introduction and Approach...... 1 1.1 Background...... 1 1.2 History of EIA Process ...... 2 1.2.1 Scoping Process...... 2 1.2.2 Revision of Plan of Study for EIA...... 2 1.3 Objectives and Approach to the EIA ...... 3 1.3.1 Objectives of the EIA ...... 3 1.3.2 Approach to EIA Phase ...... 3 1.4 Assumptions and Limitations ...... 6 1.5 Report Structure...... 6 2 Legal Framework and Regulatory Requirements ...... 8 2.1 Environment Conservation Act 73 of 1989 ...... 9 2.2 National Environmental Management Act 107 of 1998 ...... 10 2.2.1 NEMA EIA Regulations...... 11 2.3 Marine Living Resources Act 18 of 1998...... 12 2.4 National Heritage Resources Act 25 of 1999 and other legislation applicable to marine archaeological sites...... 13 2.5 Dumping at Sea Control Act 73 of 1980 ...... 15 2.6 National Ports Act 12 of 2005 ...... 16 2.7 London Protocol 1996 ...... 17 2.8 Strategic Environmental Assessment: Port of Cape Town...... 18 3 Project Description...... 20 3.1 Project Motivation ...... 22 3.2 Basin Deepening...... 24 3.2.1 Characterisation of Material to be Dredged...... 24 3.2.2 Drilling and Blasting ...... 28 3.2.3 Dredging Equipment...... 28 3.2.4 Dredging Options ...... 33 3.2.5 Transport and Disposal of Dredge Spoil...... 39 3.3 Berth Upgrades ...... 40 3.3.1 Berth Deck Alteration Equipment ...... 40 3.3.2 Berth Deck Alteration Method ...... 40 3.3.3 The Installation of New Cranes ...... 43 3.4 Project Timeline...... 45 3.5 Contractors’ Yard ...... 45 4 Project Alternatives...... 50 4.1 “No Development” Alternative ...... 50 4.2 Project Aspect Alternatives ...... 50
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page iii 4.2.1 Project Aspect Alternatives Screened Out After the Scoping Phase ...... 51 4.2.2 Project Aspect Alternatives Considered in the EIA Phase ...... 52 4.3 Other Alternatives Considered in the EIA Phase...... 55 5 Description of the Affected Environment...... 56 5.1 Biophysical Environment ...... 56 5.1.1 Climate ...... 56 5.1.2 Geology ...... 57 5.1.3 Oceanography...... 61 5.1.4 Marine Ecosystem ...... 62 5.2 Socio-Economic and Cultural Environment ...... 65 5.2.1 Port Infrastructure and Operations...... 65 5.2.2 Port of Cape Town within the Socio-Economic Environment of the Western Cape...... 65 5.2.3 Tourism and Recreational Activities in Table Bay...... 66 5.2.4 Marine Archaeology...... 66 5.2.5 Visual and Aesthetic Environment ...... 67 5.2.6 Traffic and Transport...... 69 6 Public Consultation Process ...... 71 6.1 Introduction...... 71 6.2 Objectives of the Public Consultation Process ...... 71 6.3 Public Consultation during the Scoping Phase ...... 71 6.3.1 Issues raised during Scoping Process ...... 72 6.4 Public Participation during the EIA Phase...... 74 6.4.1 Identification of IAPs ...... 74 6.4.2 Discussions with Key Stakeholders...... 75 6.4.3 Notification of Draft EIR Release for Comment ...... 75 6.4.4 Release of Draft EIR for comment ...... 75 6.4.5 Public Open Day...... 75 7 Assessment of Environmental Impacts...... 76 7.1 Introduction...... 76 7.2 Impact Rating Methodology ...... 76 7.2.1 Impact Rating Procedure ...... 76 7.2.2 Cumulative and Indirect Impacts...... 79 7.2.3 Integration of Studies into the EIA...... 79 7.3 Potential Marine Impacts...... 79 7.3.1 Marine Impact Study Introduction and Terms of Reference ...... 79 7.3.2 Marine Baseline Information...... 82 7.3.3 Marine Impact Assessment...... 85 7.3.4 Cumulative Impacts on the Marine Environment...... 113 7.3.5 Recommended Mitigation Measures: Potential Marine Impacts...... 113 7.4 Potential Noise, Shock and Vibration Impacts ...... 115
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page iv 7.4.1 Noise, Shock and Vibration Study Introduction, Terms of Reference and Methodology ...... 115 7.4.2 Noise, Shock and Vibration Baseline Information ...... 117 7.4.3 Noise, Shock and Vibration Impact Assessment ...... 119 7.4.4 Recommended Mitigation Measures: Potential Noise and Vibration Impacts ...... 126 7.5 Potential Traffic Impacts ...... 127 7.5.1 Traffic Study Introduction, Terms of Reference and Methodology...... 127 7.5.2 Traffic Study Baseline Information ...... 128 7.5.3 Traffic Study Impact Assessment...... 130 7.5.4 Recommended Mitigation Measures: Potential Traffic Impacts ...... 135 7.6 Potential Visual Impacts ...... 135 7.6.1 Visual Study Introduction, Terms of Reference and Methodology ...... 135 7.6.2 Visual Study Baseline Information...... 135 7.6.3 Visual Study Impact Assessment...... 136 7.6.4 Recommended Mitigation Measures: Potential Visual Impacts ...... 140 7.7 Potential Maritime Archaeological Impacts ...... 140 7.7.1 Maritime Archaeology Study Introduction, Terms of Reference and Methodology ...... 140 7.7.2 Maritime Archaeology Study Baseline Information...... 141 7.7.3 Maritime Archaeology Study Impact Assessment...... 141 7.7.4 Mitigation measures: Maritime Archaeological Impact ...... 143 8 Evaluation and Recommendations ...... 145 8.1 Evaluation...... 145 8.2 Environmental Suitability of Alternative Dredge Disposal Sites ...... 149 8.3 Principal Findings and Key Decision Making Factors ...... 149 8.4 Recommendations...... 153 8.4.1 General Recommendations...... 153 8.4.2 Specific Recommendations and Mitigation Measures...... 154 9 Way Forward ...... 159 10 References ...... 161
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page v Appendices Appendix A: Plan of Study for EIA and Acceptance by DEAT Appendix B: Public Consultation Appendix B1: List of Registered Stakeholders Appendix B2: Letter to Registered Stakeholders Appendix C: Marine Specialist Study Appendix C1: Integrated Marine Specialist Study Appendix C2: Dredge Disposal Site Selection and Characterisation Appendix C3: Dredging and Disposal of Dredge Spoil Modelling Specialist Study Appendix C4: Sediment Toxicology and Ecology Specialist Study Appendix C5: Shoreline Stability Specialist Study Appendix D: Maritime Archaeology Specialist Study Appendix E: Noise and Vibration Specialist Study Appendix F: Traffic Specialist Study Appendix G: Visual Specialist Study
Please note: Appendices C to G, containing copies of the specialist studies conducted for this EIA, are contained in a separate volume.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page vi List of Tables Table 1-1: Activities undertaken during the berth deepening EIA...... 5 Table 1-2: Specialist studies undertaken during the EIA Phase...... 5 Table 3-1: Berth Lengths in Ben Schoeman Dock...... 20 Table 3-2: Dredge material...... 24 Table 3-3: Dredge rates for Option 1 (CSD and BHD)...... 33 Table 3-4: Dredge rates for Option 2 (TSHD and BHD) ...... 35 Table 3-5: Dredge rates for Option 3 ...... 37 Table 3-6: Spoil disposal rates for dredging options 1 – 3...... 39 Table 3-7: Approximate Crane Dimensions...... 45 Table 4-1: Project alternatives identified during scoping...... 51 Table 5-1: Average temperatures and rainfall during winter...... 56 Table 5-2: Average temperatures and rainfall during summer...... 56 Table 6-1: Summary of consultation activities during the Scoping Phase ...... 72 Table 6-2: Issues identified in the Scoping phase requiring further investigation ...... 73 Table 6-3: Summary of consultation activities during the EIA Phase...... 74 Table 7-1: Criteria used to determine the consequence of the impact...... 77 Table 7-2: Method used to determine the consequence score ...... 77 Table 7-3: Probability classification...... 77 Table 7-4: Impact significance ratings ...... 78 Table 7-5: Impact status and confidence classification...... 78 Table 7-6: Significance of the potential removal of biological communities in the dredge target areas ...... 87 Table 7-7: South African Water Quality Guidelines for the water column...... 88 Table 7-8: ANZECC water quality guidelines ...... 89 Table 7-9: Significance of the potential generation of suspended sediment plumes and potential impact on biological organisms in the harbour...... 90 Table 7-10: Significance of potential settlement of suspended sediments and the effects on sediment biota and ecological processes...... 91 Table 7-11: Significance of the potential importation of alien species by dredgers and associated ecological effects in the harbour ...... 92 Table 7-12: Significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 1 ...... 95 Table 7-13: Significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 2 ...... 97 Table 7-14: Significance of the potential alteration of benthic biological communities through toxins in dredge spoil at Site 1...... 98 Table 7-15: Significance of the potential alteration of benthic biological communities through toxins in dredge spoil at Site 2...... 98 Table 7-16: Significance of the potential effects of turbidity from dredge spoil disposal on habitats adjacent to Site 1...... 105
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page vii Table 7-17: Significance of the potential effects of turbidity from dredge spoil disposal on habitats adjacent to Site 2...... 105 Table 7-18: Potential effects on water quality in the Table Mountain National Park MPA and resulting effects on biota as a result of sediment plumes for disposal at Site 1...... 107 Table 7-19: Potential effects on water quality in the Table Mountain National Park MPA and resulting effects on biota as a result of sediment plumes for disposal at Site 2...... 107 Table 7-20: Significance of the potential importation of alien species by dredgers and associated ecological effects at dredge disposal sites...... 108 Table 7-21: Significance of the potential effects of turbidity during dredge spoil dumping on endangered coastal seabirds ...... 109 Table 7-22: Significance of the potential erosion of the shoreline as a result of dredge disposal at Site 1....110 Table 7-23: Significance of the potential erosion of the shoreline as a result of dredge disposal at Site 2....111 Table 7-24: Significance of the potential deposition of sediments from the dredging operations in existing dredge areas and/or navigation channels ...... 112 Table 7-25: Significance of the potential interference with existing shipping...... 113 Table 7-26: Measured ambient noise levels in and around the Port...... 117 Table 7-27: Distances of residential areas surrounding the port from the construction area ...... 118 Table 7-28: Adding and subtracting noise levels ...... 120 Table 7-29: Calculated noise levels at discrete receptors...... 123 Table 7-30: Significance of the potential noise impacts...... 124 Table 7-31: Recommended maximum threshold values of peak particle velocity for different types of structure...... 125 Table 7-32: Significance of the potential impacts of blasting and vibrations ...... 126 Table 7-33: Level of Service indicators for intersections...... 128 Table 7-34: Predicted external hourly trips generated during construction periods...... 131 Table 7-35: Significance of potential increase in heavy vehicle traffic on the external road network as a result of temporary crane rail and berth construction ...... 133 Table 7-36: Significance of potential increase in heavy vehicle traffic on the internal road network ...... 134 Table 7-37: Significance of potential conflict between construction traffic and train movements...... 134 Table 7-38: Significance of the potential visual impact of dredge plume...... 138 Table 7-39: Significance of the potential visual impact of construction activities...... 138 Table 7-40: Approximate dimensions of cranes...... 139 Table 7-41: Significance of the potential visual impact from new cranes ...... 139 Table 7-42: Significance of potential impact on marine archaeology...... 142 Table 8-1: Impact rating summary for the proposed upgrades to berths and associated deepening of Ben Schoeman Dock ...... 146
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page viii List of Figures Figure 1-1: The EIA Process ...... 4 Figure 2-1: Table Mountain NP MPA northern boundary ...... 13 Figure 2-2: Table Bay Rock Lobster Sanctuary ...... 13 Figure 3-1: Aerial view of the Ben Schoeman Dock...... 20 Figure 3-2: Location of the Ben Schoeman Dock and berths in the Port of Cape Town ...... 21 Figure 3-3: Decrease in vessel movements per year ...... 22 Figure 3-4: Increase in TEU volumes shipped per year ...... 22 Figure 3-5: Extent of area to be dredged...... 25 Figure 3-6: Sediment thickness ...... 27 Figure 3-7: Schematic drawing of a Trailing Suction Hopper Dredger ...... 29 Figure 3-8: Representative photo: Trailing Suction Hopper Dredger ...... 30 Figure 3-9: Schematic drawing of a Cutter Suction Dredger ...... 31 Figure 3-10: Representative photo: Cutter Suction Dredger ...... 31 Figure 3-11: Schematic drawing of a Backhoe Dredger ...... 32 Figure 3-12: Representative photo: Backhoe Dredger ...... 32 Figure 3-13: Indicative dredging timelines: Option 1 (above – higher BHD dredge rate, below – lower BHD dredge rate) ...... 34 Figure 3-14: Indicative dredging timelines: Option 2 (above – higher BHD dredge rate, below – lower BHD dredge rate) ...... 36 Figure 3-15: Indicative dredging timelines: Option 3 (above – higher BHD dredge rate, below – lower BHD dredge rate) ...... 38 Figure 3-16: Proposed deck upgrades ...... 41 Figure 3-18: Existing Cranes at Ben Schoeman Dock ...... 44 Figure 3-19: Diagram of Existing Crane – Noell ...... 44 Figure 3-20: Diagram of proposed new Cranes...... 45 Figure 3-21: Position of Culemborg Site, to be used as Contractors Yard...... 46 Figure 3-22: Culvert underneath N1 providing access to the Culemborg Site...... 47 Figure 3-23: Proposed Access to Contractor's Yard...... 49 Figure 4-1: Proposed dredge spoil disposal sites...... 54 Figure 5-1: Bathymetry of Table Bay ...... 58 Figure 5-2: Sediment and Bedrock Distribution in Table Bay...... 59 Figure 5-3: Shoreline features and key faunal populations in Table Bay...... 60 Figure 5-4: Macrobenthos abundance and biomass at dredge disposal sites 1 and 2...... 64 Figure 5-5: Industrial, residential and commercial areas around Port of Cape Town...... 68 Figure 5-6: Port of Cape Town and surroundings ...... 69 Figure 7-1: Typical distribution of wave heights and directions in Table Bay ...... 84 Figure 7-2: Predicted exceedence (days) of 20mg/l suspended sediment concentration at mid-depth during cutter suction dredged operations...... 90
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page ix Figure 7-3: Predicted mean thickness of deposition at dump Site 1 for the cutter suction dredger ...... 94 Figure 7-4: Predicted mean thickness of deposition at dump Site 2 for the cutter suction dredger ...... 96 Figure 7-5: Predicted exceedance (days) of 20mg/l of suspended sediment within the bottom layer of the greater study area for the dredge spoil dumped at Site 1 (worst case scenario) ...... 100 Figure 7-6: Predicted exceedance (days) of 20mg/l of suspended sediment within the bottom layer of the greater study area for the dredge spoil dumped at Site 2 (worst case scenario) ...... 101 Figure 7-7: Predicted exceedance (days) of 100mg/l of suspended sediment in the bottom layer of the greater study area for Site 1 (worst case scenario)...... 103 Figure 7-8: Predicted exceedance (days) of 100mg/l of suspended sediment in the bottom layer of the greater study area for Site 2 (worst case scenario)...... 104 Figure 7-9: Location of noise monitoring points and residential areas surrounding the port...... 117 Figure 7-10: Daytime noise contours during construction ...... 121 Figure 7-11: Night-time noise contours during construction ...... 122 Figure 7-12: Primary routes and rail lines serving the Port of Cape Town...... 128
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page x Glossary
Archaeology The scientific study of aspects of the human past, primarily through material evidence. Artifact An object used or produced by people in the past. Ballast Water Use of water in specialised ballast tanks to aid in controlling a ship’s trim and draft, especially when sailing empty or with light cargoes. Bathymetry The sea bed “topography” derived from measurements of depths of water. Before Present An archaeological term denoting the number of years before 1950 (“present”), when Carbon Dating was introduced. Benthic Referring to organisms living in, or on, the sediments of aquatic habitats (lakes, rivers, ponds, sea etc.). Benthos The sum total of organisms living in, or on, the sediments of aquatic habitats Biodiversity The variety of life forms, including the plants, animals and micro-organisms, the genes they contain and the ecosystems and ecological processes of which they are a part. Bulking The process whereby the volume of sand or sediment is increased by increasing the porosity or instititial spaces between the individual grains within the sediment. This typically occurs when sediments are excavated/dredged. Chart Datum Reference measure of depth. In the Port of Cape Town, Chart Datum is 0.7 m below mean sea level (i.e. 14 m below Chart Datum is the same as 14.7 m below mean sea level). Community An assemblage of organisms characterised by a distinctive combination of species occupying a common environment and interacting with one another. Community structure All the types of taxa present in a community and their relative abundance. Contaminant Biological (e.g. bacterial and viral pathogens) and chemical introductions capable of producing an adverse response (effect) in a biological system, seriously injuring structure or function or producing death. Cope line The outer edge of the quay wall. dBA Unit of sound level. The weighted sound pressure level by the use of the A metering characteristic and weighting specified in ANSI Specifications for Sound Level Meter. Decibel (dB) A measure of sound. It is equal to 10 times the logarithm (base 10) of the ratio of a given sound pressure to a reference sound pressure. The reference sound pressure used is 20 micropascals, which is the lowest audible sound. Effluent A complex waste material (e.g. liquid industrial discharge or sewage) that may be discharged into the environment. Environment The external circumstances, conditions and objects that affect the existence and development of an individual, organism or group. These circumstances include biophysical, social, economic, historical and cultural aspects. Environmental Impact A study of the environmental consequences of a proposed course of action. Assessment (EIA) Excavation The practice of documenting, uncovering and recovering of artifacts and finds, together with associated information Habitat The place where a population (e.g. animal, plant, micro-organism) lives and its surroundings, both living and non-living. LC Annex I substances Annex I substances are defined in the London Convention to include organohalogen compounds, mercury and mercury compounds, cadmium and cadmium compounds, persistent plastic or similar synthetic compounds, crude oil and associated wastes, radioactive wastes, material for biological and chemical warfare. The London Convention prohibits the dumping of wastes or other matter listed in Annex I.
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LC Annex II substances Annex II substances include wastes containing significant amounts of arsenic, beryllium, chromium, copper, lead, nickel, vanadium, zinc and compounds of these metals, organosilicon compounds, cyanides, fluorides, pesticides and their by-products and any other material, though of a non-toxic nature, that may become harmful due to the quantities in which they are dumped. The dumping of wastes or other material listed in Annex II requires a prior special permit from the relevant national authority. Macrofauna Animals >1 mm in size Maritime archaeology The scientific study of people’s past relations to the sea through surviving material evidence and all available additional evidence of whatever nature Pollution The introduction of unwanted components into waters, air or soil, usually as result of human activity; e.g. hot water in rivers, sewage in the sea, oil on land. Probable Effect Level A threshold above which in situ adverse biological effects are probable ( i.e. a threshold (PEL) value above which adverse biological affects usually or always occur). Prohibition category Substances at concentrations exceeding a level (Prohibition Level) that will cause significant deleterious biological responses. These materials may not be dumped unless made acceptable for dumping through the use of management techniques or processes that could include treatment, such as separation of contaminated fractions and disposal management techniques such as placement on or burial in the sea floor followed by clean sediment capping, utilization of geo-chemical interactions and transformations of substances in dredged material when combined with sea water or bottom sediment, selection of special sites such as abiotic zones, or methods of containing dredged material in a stable manner. Recruitment The replenishment or addition of individuals of an animal or plant population through reproduction, dispersion and migration. Scoping A procedure to consult with stakeholders to determine issues and concerns and for determining the extent of and approach to an EIA, used to focus the EIA. Scoping report A written report describing the issues identified to date for inclusion in an EIA. Scour protection trench A trench created to contain the scour protection system to ensure that the top of the scour protection does not protrude above the dock bed level. Scour protection A protection system used to prevent undermining of a structure through scour by ship propellers, bow thrusters, currents or waves. It is proposed to protect the quay wall in this instance. Sediment Unconsolidated mineral and organic particulate material that settles to the bottom of the aquatic environment. Special care category substances at concentrations lying above a lower limit below which there are little environmental concerns and below an upper limit that avoids acute or chronic effects on human health or on sensitive marine organisms representative of the marine ecosystem. Dredge material in the Special Care require a more detailed assessment before their suitability for dumping can be determined. Species A group of organisms that resemble each other to a greater degree than members of other groups and that form a reproductively isolated group that will not produce viable offspring if bred with members of another group. Surficial sediments Those sediments on the seabed located at the seawater - seabed interface. Suspended material Total mass of material suspended in a given volume of water, measured in mg/l. Taxon (Taxa) Any group of organisms considered to be sufficiently distinct from other such groups to be treated as a separate unit (e.g. species, genera, families). Threshold Effect Level A threshold value below which in situ adverse biological effects are considered unlikely ( i.e. (TEL) represents no significant hazard to aquatic organisms Toxicity The inherent potential or capacity of a material to cause adverse effects in a living organism. Turbidity Measure of the light-scattering properties of a volume of water. Visual absorption The potential of an area to conceal the proposed development, or absorb the visual impact. capacity Vulnerable A taxon or species is vulnerable when it is not Critically Endangered or Endangered but is facing a high risk of extinction in the wild in the medium-term.
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Abbreviations
ANZECC Australian and New Zealand Environment Conservation Council BHD Backhoe Dredger BP Before Present BSD Ben Schoeman Dock CD Chart Datum CSD Cutter Suction Dredger CSIR Council for Scientific and Industrial Research DEA&DP Department of Environmental Affairs and Development Planning (Provincial) DEAT Department of Environmental Affairs and Tourism (National) ECA Environment Conservation Act EIA Environmental Impact Assessment EIR Environmental Impact Report EMP Environmental Management Plan GN Government Notice HWC Heritage Western Cape IAPs Interested and Affected Parties IUCN International Union for Conservation of Nature and Natural Resources LOS Level of Service MCM Marine and Coastal Management Directorate of DEAT MPA Marine Protected Area NEMA National Environmental Management Act NP National Park NPA National Ports Authority of South Africa PoSEIA Plan of Study for EIA PCP Public Consultation Process PPV Peak Particle Velocity SAHRA South African Heritage Resources Agency SAMSA South African Maritime Safety Authority SDF Spatial Development Framework for Port of Cape Town TEU Twenty-foot Equivalent Unit TSHD Trailing Suction Hopper Dredger RoD Record of Decision UNESCO United Nations Educational, Scientific and Cultural Organisation VAC Visual Absorption Capacity
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 The Administrative Building Albion Spring 183 Main Road 7700, Rondebosch
Postnet Suite #206 Private Bag X18 Rondebosch 7701 South Africa
e-Mail: [email protected] URL: http://www.srk.co.za
Tel: +27 (21) 659 3060 Fax: +27 (21685 7105
February 2007 367079 Proposed Upgrade to Berths 601, 602, 603 and 604 and Associated Deepening of the Ben Schoeman Dock at the Port of Cape Town - Draft Environmental Impact Report 1 General Introduction and Approach
1.1 Background As part of a programme for improving the efficiency of the Port of Cape Town, Transnet Limited (“Transnet”), including the two divisions of the National Ports Authority of South Africa (NPA) and South African Port Operations (SAPO), proposes to undertake the following activities:
• Deepening the Ben Schoeman dock (BSD);
• Conduct upgrades to berths 601, 602, 603 and 604; and
• Replace gantry cranes with new cranes with a higher and wider reach. These upgrades are necessary to accommodate larger container vessels that have a greater draught (i.e. require a greater basin depth) and beam (i.e. width). In terms of the Environmental Impact Assessment (EIA) Regulations promulgated under section 21 of the Environment Conservation Act (Act No. 73 of 1989) (ECA) 1, the proposed activities require environmental authorisation from the relevant authority prior to commencement.
1 Since the EIA application was lodged prior to the promulgation of the new EIA Regulations issued under the National Environmental Management Act (Act No. 107 of 1998) in 2006, the remainder of the process is to be completed in terms of the Environmental Conservation Act (Act No. 73 of 1989). Partners MJ Braune, JM Brown, JAC Cowan, CD Dalgliesh, T Hart, PR Labrum, LGA Maclear, RRW McNeill, HAC Meintjes, Cape Town +27 (0) 21 409 2400 BJ Middleton, MJ Morris, GP Murray, GP Nel, VS Reddy, PN Rosewarne, PE Schmidt, PJ Shepherd, AA Smithen, , PJ Terbrugge, KM Uderstadt, DJ Venter, HG Waldeck, A Wood Durban +27 (0) 31 312 1355 Directors AJ Barrett, PR Labrum, BJ Middleton, MJ Morris, PE Schmidt, PJ Terbrugge, MB Zungu, S Mayekiso Associates JCJ Boshoff, SA McDonald, DM Duthe, R Gardiner, WA Naismith, JP Odendaal, VM Simposya, D Visser, East London +27 (0) 43 748 6292 AC White, AC Woodford
Consultants AC Burger, B Sc (Hons); IS Cameron-Clarke, PrSci Nat, MSc; JH de Beer, PrSci Nat, MSc; GA Jones, PrEng, Harare +263 (4) 496 182 PhD; WD Ortlepp, PrEng, Meng; TR Stacey , PrEng, DSc; OKH Steffen, PrEng, PhD; RJ Stuart, PrTech Eng, GDE; DW Warwick, PrSci Nat, BSc (Hons) Johannesburg +27 (0) 11 441 1111 Corporate Shareholder: Kagiso Enterprises (Pty) Ltd Pietermaritzburg +27 (0) 33 345 6311
SRK Consulting (South Africa) (Pty) Ltd Port Elizabeth +27 (0) 41 581 1911 Reg No 1995.012890.07 Pretoria +27 (0) 12 361 9821
Rustenburg +27 (0) 14 594 1280
SRK Consulting BSD Deepening EIR Page 2
1.2 History of EIA Process
1.2.1 Scoping Process In 2005, NPA commissioned Shangoni Consulting to undertake the Scoping Phase of the EIA for the “Proposed Upgrade to Berths 601, 602, 603 and 604 and Associated Deepening of the Ben Schoeman Dock at the Port of Cape Town” (“Berth Deepening EIA”). The Scoping Study was concluded and submitted to the provincial Department of Environmental Affairs and Development Planning (DEA&DP) for authorisation in April 2005 2. The Scoping Report was accepted by the national Department of Environmental Affairs and Tourism (DEAT) on 9 June 2005 and a Plan of Study for the EIA phase (PoSEIA) of the Berth Deepening EIA was subsequently submitted by the CSIR to DEAT/DEA&DP for authorisation in April 2006. At the time of compilation and submission of the Scoping Report and PoSEIA, the proposed activities investigated in the Berth Deepening EIA were linked to the proposed Container Terminal Expansion project. This linkage gave rise to the identification of particular alternatives that were to be assessed in the Berth Deepening EIA. However, Transnet has subsequently separated the two projects, which are independent of each other, and will be assessed in separate EIA’s. As a result, the scope of activities and alternatives to be assessed in this Berth Deepening EIA have been amended.
1.2.2 Revision of Plan of Study for EIA In August 2006, SRK Consulting (SRK) was appointed to undertake the EIA phase of the Berth Deepening EIA (i.e. the deepening of Ben Schoeman dock, and upgrade to the berths, but excluding the container terminal expansion). SRK revised the PoSEIA previously submitted to take account of the amended scope of activities and alternatives. The revised PoSEIA contained the following key amendments:
• Details of the new EIA Consultants (i.e. SRK Consulting);
• Revised scope of works and changes in alternatives to be assessed in the EIA; and
• Changes in applicants details 3 This PoSEIA was submitted to DEAT on 5 September 2006 and was accepted on 31 October 2006.
2 The decision-making authority for this application was initially delegated from the national Department of Environmental Affairs and Tourism (DEAT, charged with issuing authorizations lodged by state organisations) to the provincial Department of Environmental Affairs and Development Planning (DEA&DP) in June 2005. SRK has however been instructed that decision-making will revert to DEAT who will request DEA&DP to provide comment on relevant documents. SRK will thus submit documents to and communicate primarily with DEAT (and copy all such correspondence and documentation to DEA&DP) 3 Although the original application was submitted under the name of NPA, it has since been confirmed that the NPA does not constitute a legal body in its own right. Applications are thus to be submitted under the name of Transnet.
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1.3 Objectives and Approach to the EIA
1.3.1 Objectives of the EIA The main objectives of the EIA are to:
• Inform the broadest possible range of Interested and Affected Parties (IAPs) about the proposed project and the EIA process followed;
• Obtain contributions of IAPs (including the applicant, consultants, relevant authorities and the public) and ensure that all issues, concerns and queries raised are fully documented and addressed in this report;
• Gather issues and concerns of IAPs to identify, screen and evaluate potential "fatal flaws" in the proposals 4;
• Identify and assess significant impacts associated with the proposed deepening of Ben Schoeman dock, and associated upgrades to berths 601, 602, 603 and 604;
• Indicate whether the two possible sites identified for the disposal of dredge spoil are environmentally acceptable locations;
• Formulate mitigation measures to minimise impacts and enhance benefits; and
• Produce a Final Environmental Impact Report (EIR) which will help DEAT to decide whether (and under what conditions) to authorise the proposed project.
1.3.2 Approach to EIA Phase The general approach adopted in this study has been guided by applicable legislation (see Chapter 2), and by the principles of Integrated Environmental Management (IEM). The IEM principles require that environmental factors associated with a proposed development are considered timeously so that appropriate design and planning modifications can be made to address critical environmental concerns. In accordance with the Integrated Environmental Management guidelines, an open, transparent approach, which encourages accountable decision-making, has been adopted. The underpinning principles of IEM require:
• informed decision making;
• accountability for information on which decisions are made;
• a broad meaning to the term “environment”;
• an open participatory approach in the planning of proposals;
• consultation with interested and affected parties;
• due consideration of alternative options;
4 Note that the gathering of issues and concerns of IAPs to screen the proposal and identify fatal flaws was primarily undertaken during the scoping phase of the project, although the issues and concerns are addressed during the EIA phase.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 4 • an attempt to mitigate negative impacts and enhance positive impacts of proposals;
• an attempt to ensure that the social costs of development proposals are outweighed by the social benefits;
• democratic regard for individual rights and obligations;
• compliance with these principles during all stages of the planning, implementation and decommissioning of proposals; and
• the opportunity for public and specialist input in the decision-making process. The approach has also been governed by the National Environmental Management Act, No 107 of 1998 (NEMA) and the ECA EIA regulations. The EIA regulations are more focused and practical and help to determine the detailed approach to, and define the objectives of, the EIA. Figure 1-1 below shows schematically the various elements which comprise the EIA process and the sequence in which they occur.
BSD Project - EIA Process
Plan of Study for Scoping PUBLIC INVOLVEMENT
Scoping Scoping Report Public Consultation accepted by DEAT in Scoping Report June 2005
Review
If more information is required by If no more DEAT information is required by Environmental DEAT Impact Assessment
Aug 2006 – Mar 2007
Record of Decision
Opportunity for Appeal
Figure 1-1: The EIA Process
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 5 The activities undertaken to date in the EIA Phase, following the completion and acceptance of the Scoping Study submitted by Shangoni Consulting, are outlined in Table 1-1. Table 1-1: Activities undertaken during the berth deepening EIA Activity Objectives EIR Reference Submission of Inform authorities of the proposed EIA Process; Appendix A (revised) Plan of Inform authorities of the change in scope of the EIA and Study for EIA alternatives to be considered in the EIA; Inform authorities of the proposed terms of reference for specialist studies; and Gain input on the required scope and content of the Environmental Impact Report and associated Specialist Studies. Stakeholder Notify all IAPs registered during the scoping process of the Appendix B consultation change in scope of the EIA and alternatives to be considered in the EIA; Ensure that the requirements of key stakeholders (including DEAT Marine and Coastal Management [MCM] and the Two Oceans Aquarium) were identified. Specialist Studies Provide a description of the affected environment; Chapter 6 Identify the impacts of the project and assess the significance of Appendix C-G the impacts; Recommend mitigation measures to reduce the impacts; and Provide an indication of the suitability of the location, blasting method, dredge spoil disposal sites and the proposed berth extension. Draft Environmental Integrate and evaluate the assessment of environmental impacts SRK Draft Report Impact Report undertaken by specialists; 367079/2 Indicate the environmental suitability of the activities involved in the berth deepening project; Identify the preferred alternative site (if applicable) for the disposal of dredge spoil, based on all specialist studies; and Present the overall findings of the EIA in a draft format for public and authority comment. The range of specialist studies undertaken during the EIA phase were informed by the issues identified in the Final Scoping Report as warranting further investigation. The specialist studies are listed in Table 1-2. Results from those studies have been incorporated into the EIR, particularly into the project description (Chapter 3), description of the affected environment (Chapter 5), and impact assessment (Chapter 7). Table 1-2: Specialist studies undertaken during the EIA Phase Specialist Study Specialist Integrated Marine Specialist Study, summarising the Roy van Ballegooyen, CSIR following marine specialist studies: Dredge Disposal Site Selection and Characterisation Roy van Ballegooyen, CSIR Dredging and Disposal of Dredge Spoil Modelling Roy van Ballegooyen, CSIR Specialist Study Sediment Toxicology and Marine Ecology Specialist Dr. Robin Carter, Lwandle Technologies Study Shoreline Stability Specialist Study Geoff Smith, CSIR Noise and Vibration Specialist Study Demos Dracoulides, DDA Environmental Traffic Specialist Study Stef Naudé, HHO Africa Visual Specialist Study Belinda Gebhardt, SRK Consulting Maritime Archaeology Specialist Study Bruno Werz
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1.4 Assumptions and Limitations The findings of the report are affected by the following:
• It has been assumed that information provided by other consultants, specialists and the proponent is accurate with respect to the proposed deepening of the BSD, upgrades to the berths and associated activities; the construction methods and equipment to be used;
• It is assumed that the assessment of the nature and significance of the impacts associated with the project is objective and not influenced by any bias on the part of any party;
• Assessment of the significance of impacts of the proposed development on the affected environment has been based on the assumption that the activities will be undertaken within the constraints of the project description provided in Chapter 3 of this report. If there are any substantial changes to the project description, the significance of impacts may need to be reassessed;
• The extensive public participation process undertaken during the scoping phase of this project has identified all relevant concerns of Interested and Affected Parties (IAPs) related to the proposed berth deepening at Port of Cape Town; and
• Transnet will in good faith implement the mitigation measures identified in this report.
1.5 Report Structure This report describes the proposed activity and its context, details the public participation process followed, rates the impacts of the proposed upgrading of the berths and deepening of the dock, indicates the acceptability of each of the alternative dredge disposal sites and presents a suite of findings and recommendations.
Chapter 1: Introduction Provides an introduction and background to the proposed project and outlines the approach to the study.
Chapter 2: Legislative Framework and Regulatory Requirements Provides an overview of the main South African environmental legislation as well as the key policies and guidelines applicable to the proposed project.
Chapter 3: Project Description Provides Transnet’s motivation for the project and a description of the proposed development activities.
Chapter 4: Project Alternatives Provides a brief description of the alternatives that have been considered during scoping, providing motivation for the exclusion of certain alternatives from the EIA phase. Alternatives which are assessed in the EIA are discussed in more detail.
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Chapter 5: Affected Environment Briefly describes the biophysical and socio-economic receiving environments that DEAT will consider in their assessment of the project.
Chapter 6: Public Consultation Process Details the approach to public consultation and the key issues and concerns raised by IAPs.
Chapter 7: Assessment of Environmental Impacts Identifies and rates environmental impacts associated with the proposed project and recommends mitigation measures.
Chapter 8: Evaluation and Recommendations Indicates the environmental acceptability of the proposed project and each of the two alternative dredge disposal sites, evaluates the proposed project and presents the principal findings, key decision factors for DEAT to consider and recommended mitigation measures, which it is assumed will be implemented.
Chapter 9: Way Forward Outlines the remaining steps in the EIA process, including the issuing of a Record of Decision (RoD) by DEAT. Please note: Appendices C to G, containing copies of the specialist studies conducted for this EIA, are contained in a separate volume.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 8 2 Legal Framework and Regulatory Requirements There are a number of regulatory requirements at local, provincial and national level with which the proposed alteration of the BSD will have to conform. Some of the key environmental legal statutes include:
• Environmental Impact Assessment Regulations, promulgated in terms of the Environment Conservation Act 73 of 1989;
• National Environmental Management Act 107 of 1998;
• Marine Living Resources Act 18 of 1998;
• National Heritage Resources Act 25 of 1999 (and other relevant legislation applicable to archaeological material at sea);
• Dumping at Sea Control Act 73 of 1980 5; and
• National Ports Act 12 of 2005. Other guidelines and policy documents applicable to the proposed activities include:
• London Protocol of 1996 (on the Prevention of Marine Pollution by Dumping of Wastes and other Matter);
• Strategic Environmental Assessment: Port of Cape Town;
• National Ports Authority policies and management plans, including but not limited to:
− NPA Environmental/SHEQ Policy;
− NPA Environmental Management System;
− NPA Waste Management Plan;
− NPA Ballast Water Management Plan;
− NPA Marine Mammal & Seabird Management Plan; and
− NPA Dredging Environmental Management Plan;
• Transnet Projects Environmental Management Plan, which includes:
− Construction Environmental Management Plan
− Standard Environmental Specification
− Project Environmental Specification A brief summary of these key requirements, as understood by SRK Consulting, is provided below. Note that other legislative requirements may pertain to the proposed development, but identification and interpretation of these is beyond the brief of this study. As such, the summary provided below is
5 As amended by the Dumping at Sea Control Amendment Act 73 of 1995 and the Environmental Law Rationalisation Act 51 of 1997.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 9 not intended to be definitive or exhaustive, and serves to highlight key environmental legislation and obligations only.
2.1 Environment Conservation Act 73 of 1989 Section 21 of the Environment Conservation Act 73 of 1989 (ECA) makes provision for the assessment of activities that are potentially substantially detrimental to the environment. Section 21 of the ECA provides that the Minister (of Environmental Affairs and Tourism) may identify those activities which (in the Minister’s opinion) may have a substantial detrimental effect on the environment. Section 22 of the ECA prohibits any person from carrying out any activities which have been identified (in terms of section 21 of the ECA) by the Minister, without prior written authorisation from the Minister or a competent authority duly designated in the Government Gazette . Section 22 of the ECA also stipulates that the authorisation may only be issued after consideration of reports concerning the impact of the proposed activity and alternative proposed activities on the environment. Activities that require authorisation from the relevant authority, based on the findings of an assessment of the impact of the proposed activity on the environment, have been identified in the Environmental Impact Assessment (EIA) Regulations 6. Identified activities that are relevant for the proposed project include: 1. The construction, erection or upgrading of: (c) with regard to any substance which is dangerous or hazardous and is controlled by national legislation- ii. manufacturing, storage, handling, treatment or processing facilities for any such substance (e) marinas, harbours and all structures below the high- water mark of the sea and marinas, harbours and associated structures on inland waters. The proposed deepening and alteration of the BSD thus requires authorisation in terms of the ECA. The environmental assessment process stipulated in the EIA Regulations is divided into a number of phases. Initially a Scoping Study , including public consultation, is completed to determine whether there are any significant environmental issues associated with the proposed activity. Should the findings of the Scoping Study indicate that there are no significant issues that require detailed assessment, or that the issues identified can be effectively managed and the authorities are of the opinion that sufficient information has been provided, a Record of Decision will be issued by the relevant authority. However, should the Scoping Study indicate that there are potentially significant environmental impacts associated with the proposed activity and the authorities require more information, they will request that a full Environmental Impact Assessment be undertaken. The EIA includes specialist assessment of any significant impacts of the proposed development as identified in the scoping process as well as alternatives (unless application has been made for exemption from consideration of alternatives), with the resulting information being presented in an Environmental Impact Report (EIR). Following public consultation regarding the findings of the EIR it is presented to the relevant authority, who will issue an RoD.
6 Government Notice No. R1182, September 1997. Promulgated in terms of Section 21 of the Environment Conservation Act 73 of 1989.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 10 The Environment Conservation Act also makes provision for appeal against any decision issued by the relevant authorities (DEAT) (Section 35(3)). In terms of the Regulations, appeals have to be lodged with the Minister of Environmental Affairs and Tourism, in writing, within thirty days of the issue of the Record of Decision.
Legal requirements for this project The proposed deepening and alteration to BSD contain elements that are listed activities requiring authorisation. Transnet is consequently obliged in terms of Sections 21, 22 and 26 of the Environment Conservation Act 73 of 1989 to obtain an authorisation in terms of section 22 of the ECA (read with the regulations promulgated in GN R1183 on 5 September 1997, as amended). The listed activity related with the storage of hazardous substances (Activity 1(c) ii) relates specifically to the temporary storage of fuel for construction purposes, while all works below the high water mark of the sea require authorisation in terms of Activity 1(e). Please Note : New EIA Regulations were promulgated in terms of the National Environmental Management Act (NEMA) in April 2006, replacing the EIA Regulations promulgated in terms of ECA. The NEMA EIA Regulations came into force on 3 July 2006 and provide that the activities identified in those Regulations may not commence without an environmental authorisation granted in terms of Section 24 of the NEMA.
2.2 National Environmental Management Act 107 of 1998 The National Environmental Management Act 107 of 1998 (NEMA) establishes a set of principles, which all authorities (organs of State) have to consider when exercising their powers, that may significantly affect the environment, for example during the granting of permits. These include the following:
• Development must be sustainable;
• Pollution must be avoided or minimised and remedied;
• Waste must be avoided or minimised, reused or recycled;
• Negative impacts must be minimised;
• Responsibility for the environmental consequences of a policy, project, product or service applies throughout its life cycle. Section 28(1) of NEMA states that “every person who causes, has caused or may cause significant pollution or degradation of the environment must take reasonable measures to prevent such pollution or degradation from occurring, continuing or recurring”. If such pollution cannot be prevented then appropriate measures must be taken to minimise or rectify such pollution. These measures may include:
• Assessing the impact on the environment;
• Informing and educating employees about the environmental risks of their work and ways of minimising these risks;
• Ceasing, modifying or controlling actions which cause pollution/degradation;
• Containing pollutants or preventing movement of pollutants;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 11 • Eliminating the source of pollution; and
• Remedying the effects of the pollution.
Legal requirements for this project Transnet has a responsibility to ensure that the proposed activity and the EIA process conform to the principles of NEMA. Transnet is obliged, under Section 28 to take actions to prevent pollution or degradation of the environment in terms of Section 28 of NEMA.
2.2.1 NEMA EIA Regulations New EIA Regulations 7 were promulgated in terms of NEMA on 3 July 2006, replacing the EIA Regulations promulgated under the ECA (see Section 2.1). Section 24 of NEMA provides that the Minister may identify (among other things) activities which may not commence without an environmental authorisation from the competent authority. Regulation 84 which provides for transitional arrangements between the previous EIA Regulations promulgated under the ECA and the new regime under the NEMA specifies that: “An application for authorisation of an activity submitted in terms of the previous regulations and which is pending when these Regulations take effect, must despite the repeal of the previous regulations, be dispensed with in terms of the previous regulations as if the previous regulations were not repealed.” The application for authorisation of the proposed BSD project was submitted to the relevant authority in 2005 and therefore falls under the EIA Regulations promulgated in terms of the ECA. However, should the proposed project include an activity that was not previously listed under the ECA EIA Regulations but is now listed under the NEMA EIA Regulations, this activity needs to be separately authorised under the new NEMA EIA Regulations. The following activities listed in terms of the new EIA Regulations apply to the proposed BSD project: GN R 3868 (s6): The excavation, moving, removal, depositing or compacting of soil, sand, rock or rubble covering an area exceeding 10 square metres in the sea or within a distance of 100 metres inland of the high-water mark of the sea. GN R 3879 (s9): Construction or earth moving activities in the sea or within 100 metres inland of the high-water mark of the sea, excluding an activity listed in item 2 of Government Notice No. R. 386 of 2006 but including construction or earth moving activities in respect of –
• facilities associated with the arrival and departure of vessels and the handling of cargo;
• piers;
• coastal harbours.
7 G.N. No. R. 385, R. 386 and R387, July 2006. Promulgated in terms of section 24(5) of NEMA (Act No. 107 of 1998). 8 Activities listed in GN R 386 require a Basic Assessment. 9 Activities listed in GN R 387 require a Full Environmental Assessment.
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Legal requirements for this project Activities listed in sections 6 of R 386 and section 9 of R 387 of the NEMA EIA Regulations are considered to cover the same components of the proposed BSD project as were listed in section 1 (e) of the previous ECA EIA Regulations. Thus the application is to be continued under the old regulations and it is assumed no authorisation is required under the new regulations.
2.3 Marine Living Resources Act 18 of 1998 The Marine Living Resources Act 18 of 1998 governs Marine Protected Areas (MPAs) and states in Section 43 that: (2) No person shall in any marine protected area, without permission in terms of subsection (3)— (b) take or destroy any fauna and flora other than fish; (c) dredge, extract sand or gravel, discharge or deposit waste or any other polluting matter, or in any way disturb, alter or destroy the natural environment; (e) carry on any activity which may adversely impact on the ecosystems of that area. (3) The Minister may, after consultation with the Forum 10 , give permission in writing that any activity prohibited in terms of this section may be undertaken, where such activity is required for the proper management of the marine protected area.
Legal requirements for this project The following areas in which marine resources are protected occur in the vicinity of Table Bay:
• Table Mountain National Park (NP) Marine Protected Area (MPA) (see Figure 2-1);
• Table Bay Rock Lobster Sanctuary (see Figure 2-2)
• Robben Island Exclusion Zone 11 and national heritage site. The proposed dredge spoil disposal sites lie just to the north of the Table Mountain NP MPA but within the Table Bay Rock Lobster Sanctuary. This is an important distinction, because the Marine Living Resources Act’s (MLRA) section 43(2) prohibits (without permission) the activities described in that sub-section if they are sought to be undertaken in (rather than adjacent to) an MPA. The proposed dump sites will not be static sites and the material deposited may be transported away from the sites as a turbid plume. The potential adverse impacts of this on the Table Mountain National Park MPA (due to the proximity of the dump sites to the MPA) have been investigated as part of the EIA process. Depending on the extent of these impacts (if any), the activities carried out by Transnet might trigger the application of the duty of care provisions in section 28 of the NEMA. The rock lobster sanctuary is not a Marine Protected Area as anticipated in the Marine Living Resources Act, but rather as a closed area in terms of Regulation 47 of the Regulations promulgated
10 “Forum” means the Consultative Advisory Forum for Marine Living Resources established under section 5 of the Act. 11 Robben Island is a provincial nature reserve with no formal marine protected area, however the sea area within a 1 nautical mile radius of Robben Island can be considered to be environmentally sensitive because of its conservation importance to African Penguins and Bank Cormorants.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 13 in terms of the MLRA (published in GN R1111 in Government Gazette 19205 of 2 September 1998). The effect of this is that “[n]o person shall, in any manner or for any purpose , engage in … disturbing West Coast Rock Lobster” 12 within that area. Insofar as the proposed dumping of dredge spoil will disturb West Coast Rock Lobster within the Table Bay Rock Lobster Sanctuary, such activity is prohibited in terms of the Regulations, and any activity which results in the disturbance of rock lobster within the closed area is unlawful. As part of the EIA process an assessment of the presence of Rock Lobster at the disposal sites and whether the turbidity plumes impact on the Rock Lobster are being investigated. GN 490 in Government Gazette 28876 of 26 May 2006 declares Robben Island (including an area of 1 nautical mile surrounding the island) as a national heritage site in terms of section 27 of the National Heritage Resources Act. 13 (NHRA). Section 27(18) of the NHRA provides that “no person may destroy, damage, deface, excavate, alter, remove from its original position, subdivide or change the planning status of any heritage site without a permit issued by the heritage resources authority responsible for the protection of such site.” Insofar as the dumping activities would destroy or damage the Robben Island heritage site then a permit would be required from SAHRA in terms of the NHRA. The potential impacts of the turbidity plumes on Robben Island heritage site have been investigated as part of the EIA process.
Table Mountain NP BSD MPA border Table Bay Rock Lobster Sanctuary
BSD
Figure 2-1: Table Mountain NP Figure 2-2: Table Bay Rock Lobster MPA northern boundary Sanctuary Source: SanParks Source: DEAT
2.4 National Heritage Resources Act 25 of 1999 and other legislation applicable to marine archaeological sites The South African legislative system includes several acts which are relevant to the protection of archaeological sites, both on land and underwater. Although most of these acts were not formulated
12 Regulation 47. 13 Act 25 of 1999.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 14 with this specific purpose of protecting archaeological sites, they contain some clauses and conditions which regulate aspects of management and control. Relevant legislation which touches on or incorporates submerged archaeological sites is described in the following acts:
• Sea Shore Act 21 of 1935 (as amended);
• Merchant Shipping Act 57 of 1951 (as amended);
• Customs and Excise Act 91 of 1964;
• Legal Succession to the South African Transport Services Act 9 of 1989;
• National Heritage Resources Act 25 of 1999. The first four acts deal mainly with the sites of shipwrecks and with shipwrecks and their contents, without specific reference to the cultural and historical-archaeological values of such remains. The National Heritage Resources Act of 1999, however, specifically acknowledges these values and includes detailed regulations in this regard. The protection and management of South Africa’s heritage resources are thus controlled by the National Heritage Resources Act 25 of 1999. It is the only act within the South African legal system which specifically attributes historical-archaeological and cultural values to shipwrecks. The Act states in Section 35(1) that “… the protection of any wreck in the territorial waters and the maritime cultural zone shall be the responsibility of SAHRA” (South African Heritage Resources Agency). In terms of the Act, historically important features such as wrecks, graves, trees, archaeological artefacts and fossil beds are protected. Similarly, culturally significant symbols, spaces and landscapes are also afforded protection. In terms of Section 38 of the National Heritage Resources Act, SAHRA can call for a Heritage Impact Assessment (HIA) where certain categories of development are proposed. The Act also makes provision for the assessment of heritage impacts as part of an EIA process and indicates that if such an assessment is deemed adequate, a separate HIA is not required. The activities identified in the Act as requiring a notification of SAHRA include:
• Section 38 (1) (c): Any development or other activity which will change the character of a site 14
• exceeding 5,000 m 2 in extent.
• The total area to be deepened by dredging amounts to approximately 1,100,000 m2 and thus exceeds the above threshold that requires notification of SAHRA.
14 “site” means any area of land, including land covered by water, and including any structures or objects thereon;
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Legal requirements for this project The Ben Schoeman Dock is an existing component of an active port, and deepening the basin, which has been previously dredged, will not change the current character of the site where large container vessels will continue to be loaded and unloaded. The activities listed in Section 38 of the Heritage Resources Act thus do not apply to the proposed project and notification of the relevant authorities is not required. Nevertheless, SAHRA was notified of the proposed project in May and October 2006 and a heritage specialist was commissioned during the EIA to assess the proposed development for potential negative impacts on heritage resources. According to SAHRA, a permit for the proposed activity is required from SAHRA, which can be issued to the project’s maritime archaeologist. SAHRA further requires the monitoring of dredging activities by a suitably qualified maritime archaeologist at the proponent’s cost.
2.5 Dumping at Sea Control Act 73 of 1980 The Dumping at Sea Control Act 73 of 1980, as amended by the Dumping at Sea Control Amendment Act 73 of 1995, controls the dumping of substances at sea. The Act lists substances that are prohibited to be dumped at sea (Schedule 1) and substances whose dumping at sea is restricted (Schedule 2): Schedule 1 prohibited substances include:
• Organohalogen compounds;
• Mercury and its compounds;
• Cadmium and its compounds;
• Persistent plastics and other persistent synthetic materials;
• High-level radio-active waste or other high-level radio-active matter; and
• Substances in whatever form produced for biological and chemical warfare. Schedule 2 restricted substances include:
• Arsenic and its compounds;
• Lead and its compounds;
• Copper and its compounds;
• Zinc and its compounds;
• Organosilicon compounds;
• Cyanides;
• Fluorides;
• Pesticides and their by-products not included in Schedule 1;
• Beryllium and its compounds;
• Chromium and its compounds;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 16 • Nickel and its compounds;
• Vanadium and its compounds;
• Containers, scrap metal and any substances or articles that by reason of their bulk may interfere with fishing or navigation;
• Radio-active waste or other radio-active matter not included in Schedule 1; and
• Ammunition. Substances listed in Schedule 1 may not be dumped at sea, while a permit must be obtained from the Minister of Environmental Affairs and Tourism (Marine and Coastal Management) if substances listed in Schedule 2 are to be dumped. In issuing a permit the Minister must take into account characteristics and composition of the substance and characteristics of the dumping or disposal site and method of disposal.
Legal requirements for this project Dredge material per se is not a listed substance under either Schedules 1 or 2 of the Act. However, Schedule 2 lists “any substances or articles that by reason of their bulk may interfere with fishing or navigation”. The dumped sediment may have an impact on wave action and vessels will dump the material within a busy shipping zone. As such a permit should be obtained. An analysis of the sediment to be dredged and disposed of has also shown that it contains trace metals (see Section 3.2.1 and CSIR, 2006b). As these are listed substances, their dumping requires a permit. This permit must be obtained from the Department of Environmental Affairs and Tourism: Marine and Coastal Management (MCM). A permit application will be submitted to MCM in parallel to the submission of the EIR to DEAT, although the permit will not be issued until a Record of Decision is issued for the proposed activities in terms of the ECA (see Section 2.1 above). As a result of this requirement, there has been ongoing correspondence between SRK Consulting and MCM, as well as Kevin Weerts, the consultant submitting the permit application on behalf of the applicant, to ensure that studies undertaken as part of the EIA process also meet the information requirements by MCM to issue the permit, once the need arises. MCM have been kept informed throughout the dredge disposal site identification and characterisation.
2.6 National Ports Act 12 of 2005 The National Ports Act 12 of 2005 aims to promote the development of an effective and productive South African ports industry that is capable of contributing to economic growth and development of the country. In terms of the Act the, relevant responsibilities of the National Ports Authority (NPA) include the maintenance and improvements of port infrastructure. The NPA is also required to regulate and control, among others, the development of ports and pollution and protection of the environment within the port limits. The NPA is required to ensure that a fair and reasonable balance is achieved between the protection of the environment and the establishment, development and maintenance of ports.
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Legal requirements for this project While promoting the upgrade of infrastructure in the Port of Cape Town to ensure that the port is able to continue contributing to the economic growth and development of the country, NPA needs to ensure that the upgrades occur in such a manner that the negative effects on the natural environment are minimized.
2.7 London Protocol 1996 The 1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and other Matter (London Convention 1972) is an international treaty that limits the discharge of wastes that are generated on land and disposed of at sea. Requirements of the London Convention has been given effect to in South African law by the Dumping at Sea Control Act and it is in terms of that Act that the activity of dumping dredge material at sea will be regulated. Annex I and Annex II of the London Convention provide lists of substances of which dumping is prohibited or requires a permit (referred to as LC Annexes in this report). In terms of this convention “special care” and “prohibition” levels of contaminant concentrations have been determined. Contaminant concentrations at “special care” limits may result in minor environmental effects, although they do not exceed the levels at which acute or chronic effects on human health or sensitive marine organisms could occur. Care must thus be exercised in the disposal of substances in this category, to ensure that the environmental effects are minimized. At “prohibition: levels, substances could cause significant deleterious biological responses. Materials falling into this category may generally not be dumped at sea The London Protocol 1996 is a separate agreement that modernized and updated the London Convention, following a detailed review that began in 1993. The London Protocol 1996 will eventually replace the London Convention. South Africa is a Contracting Party to the London Protocol 1996 and as such has to adhere to its stipulations. Article 4(1) of the London Protocol 1996 specifies that Contracting Parties shall prohibit the dumping of any wastes or other matter with the exception of those listed in Annex 1. Matter that may be considered for dumping in the sea as identified in Annex 1 of the protocol includes dredged material . However, Annex 2 specifies that both the waste and proposed dump site must be characterised as described below before a permit can be issued: Annex 2 (s8): Characterisation of the wastes and their constituents shall take into account:
• origin, total amount, form and average composition;
• properties: physical, chemical, biochemical and biological;
• toxicity;
• persistence: physical, chemical and biological; and
• accumulation and biotransformation in biological materials or sediments.
• Annex 2 (s11): Information required to select a dump-site shall include:
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 18 • physical, chemical and biological characteristics of the water-column and the seabed;
• location of amenities, values and other uses of the sea in the area under consideration;
• assessment of the constituent fluxes associated with dumping in relation to existing fluxes of substances in the marine environment; and
• economic and operational feasibility. Article 4(2) of the London Protocol 1996 states that the dumping of wastes or other matter listed in Annex 1 shall require a permit. Annex 2 (s9 and 10) further clarifies that only waste with a toxicity below a certain threshold as specified in a national Action List developed by each Contracting Party can be dumped. DEAT has the responsibility of implementing the protocol of the London Convention in South Africa.
Requirements for this project In accordance with the Dumping at Sea Control Act the applicant has to apply for a permit before dumping the dredge material at sea. Transnet needs to ensure that the permit application procedure in terms of the Dumping at Sea Control Act is taken into account (see Schedule 3 to the Act which expressly lists the factors to be taken into account by the relevant decision-making authority in granting a permit in terms of the Act). The required characterisation of the sediment to be dredged and disposed of, as well as characterisation of the proposed disposal sites (both alternatives) have been integrated into the specialist marine studies undertaken as part of this EIA, and will inform the permit application.
2.8 Strategic Environmental Assessment: Port of Cape Town A Strategic Environmental Assessment (SEA) was undertaken for the Port of Cape Town in 2004 and as a result a Sustainability Framework for the Port was developed. The SEA is related to the Port Development Framework in that it aims to provide a framework that will facilitate integrative port planning and provide solutions that are acceptable to all stakeholders from a biophysical, social and economic perspective. (CSIR, 2004) The SEA sets out a number of sustainability objectives, targets and indicators to direct future port planning and development, taking into consideration the existing state of the environment. SEA guidelines for port planning and environmental management that are of particular relevance to the proposed development can be summarised as follows: Marine Ecosystems
• For physical port expansion, consideration should be given to the impact on the sandy beach ecosystems, including assessing the impact of future port development on the shoreline stability;
• Water quality management should be implemented, including sediment quality sampling prior to dredging and dumping operations (in terms of the London Convention and Protocol); and
• Prevent the introduction of alien invasive organisms and pathogens in Table Bay by prohibiting untreated ballast water discharges in Table Bay and or the port by vessels of distant origin (which would include dredgers).
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 19 Maritime Archaeology
• Baseline studies of marine archaeology are to be undertaken in any area of proposed expansion;
• Any work in designated area must take the possible presence, important and sensitivity of maritime archaeological sites into consideration;
• Potential future surveys and excavation must be undertaken by suitably trained and qualified personnel; and
• Excavation and recovery of any material found can only be done once a licence has been issued by the Department of Customs and Excise and a permit from SAHRA. Shoreline Stability
• Computational modelling of wave transformation, resulting sediment transport and shoreline evolution should be used to assist with conceptual designs of future port expansion.
Requirements for this project Transnet must ensure that the development proposals take cognisance of the sustainability objectives and guidelines for port development, as detailed in the SEA. The requirements in terms of marine ecosystems, maritime archaeology and shoreline stability have been addressed in this EIA.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 20 3 Project Description The BSD is located within the Port of Cape Town, north-east of the Duncan Dock and east of the Victoria Basin. The basin of the BSD measures approximately 113 ha and has a depth of approximately 10 m to 15 m. The BSD has 12 berths at which ships can dock. Four berths, numbered 601 through to 604, are used for cargo handling with a total length of approximately 1.1 km. The remaining 8 berths are unsuitable for the handling of cargo. The individual lengths of each of berths 601 to 604 are indicated in Table 3-1. Table 3-1: Berth Lengths in Ben Schoeman Dock Berth Number Length 601 236 m 602 305 m 603 305 m 604 305 m Total 1,151 m Source: Transnet
NPA Building Victoria Basin
Ben Berths Schoeman 601-604 Port Dock Administration Duncan Building Dock
Culemborg Site
Figure 3-1: Aerial view of the Ben Schoeman Dock Source: Transnet Transnet proposes to undertake the following activities at the Ben Schoeman Dock within the Port of Cape Town (also see Figure 3.2):
• Deepening the Ben Schoeman Dock basin within the Port of Cape Town from current 10 - 15 m below Chart Datum (CD) to a depth of 15.5 m below CD. The total area to be deepened by dredging amounts to approximately 1,100,000 m 2 or 110 ha, from which approximately 1,230,000 m 3 of material is expected to be dredged. This also includes the dredging of a scour trench to 17.0 m below CD alongside the berths 601 to 604;
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Figure 3-2: Location of the Ben Schoeman Dock and berths in the Port of Cape Town Source: Transnet
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 22 • Widening the deck of berths 601, 602, 603 and 604 of the Ben Schoeman Dock by 10 m and constructing an additional crane rail to accommodate replacement container gantry cranes;
• Replacing four of the existing (Demag) cranes with initially six super post Panamax cranes, with the long term intention to increase the number of cranes serving the Dock;
• Minor resurfacing using concrete and asphalt paving landward of berth 601 to 604; and
• Minor additions and/or alterations to existing services. The proposed deepening of the Ben Schoeman Dock includes dredging of a layer of material approximately 4.8m thick from the area of Berth 600, 2.7m near Berth 601 and 1.5m from the western section (berths 602-604).
3.1 Project Motivation There is a global trend showing that the number of vessel movements is decreasing, while the number of TEUs (Twenty Foot Equivalent Units) moved increases year-by-year (see Figure 3-3 and Figure 3-4). These opposing trends imply that a decreasing number of vessels carry an increasing number of containers or cargo per vessel and that, as such, vessels are becoming larger.
10,000
8,000
6,000
4,000
2,000 No of vessel movements No of vessel
0 2002 2003 2004 2005
Figure 3-3: Decrease in vessel movements per year Source: Shangoni (2006)
600
500
400
300
200 No No of TEUs (1,000s)
100
0 1997 1998 1999 2000 2001 2002 2003 2004
Figure 3-4: Increase in TEU volumes shipped per year Source: Shangoni (2006)
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 23 Fifth-generation container vessels, with a capacity of approximately 4 880 TEU have come into service on the South African Trade route since 2004, while sixth-generation vessels, with a capacity of up to 6 000 TEU have already been designed and built (Shangoni, 2006). These so-called ‘new generation vessels’ typically have greater working drafts (or depths) and wider beams (or ship widths) than conventional vessels. Various shipping lines that form part of the South African European Communities Service Conference have indicated that they will be investing in such new generation container liner vessels. The larger size of vessels has three implications for ports used by those ships:
• Basins and associated berths need to be sufficiently deep to accommodate the draft of the vessels;
• Basins and associated berths need to be sufficiently wide to accommodate the beam of the vessel; and
• Ship-to-shore cranes need to have sufficient reach to be able to load and offload containers from taller and wider ships. To accommodate these larger vessels and remain competitive in a global environment, Transnet proposes to increase the current working depth of the basin and berths of the Ben Schoeman Dock at the Cape Town harbour and to install cranes with a taller and wider reach to accommodate both fifth and sixth generation container vessels. It is expected that, once deepened to a depth of 15.5m, the BSD would be suitable for the next 30 years, as container vessels are built with an anticipated lifespan of between 20 and 30 years. Moreover, it is likely that future container vessel development will result in longer and wider, but not significantly deeper vessels as further increases in the draft of vessels may start to compromise their stability (Shangoni, 2006). The expansion of Cape Town’s container handling capacity is closely linked to broader Western Cape and National economic and trade conditions. The Western Cape Province represents around 15 % of the National economy, based primarily upon the presence of Metropolitan Cape Town. The city generates around 77 % of the Region’s Gross Domestic Product (GDP) and is the major centre for population, employment and commercial activities. There is an expectation that the Western Cape economy will continue to expand between 4 and 5 % over the medium term. With the primary drivers remaining stable, expansion will be primarily led by consumer demand and capital investment. The Cape Town Metropolitan Area has a dominant position within the Western Cape with regard to commercial activity and as a consequence freight distribution. As previously stated it accounts for an estimated 77 % of the Region’s GDP, 66 % of the population and 61 % of formal employment. Reflecting this concentration, it is estimated that 75 % of Cape Town’s container throughput is generated or destined for locations within 50km of the port. Of the balance an estimated 15 % is distributed within a hinterland stretching 50-200km from the Port and the balance related to other South African destinations, notably Gauteng.
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3.2 Basin Deepening Transnet proposes to deepen the basin of the Ben Schoeman Dock from approximately 10 to 15 m below CD (although some portions of the basin are currently shallower and some deeper) to a depth of approximately 15.5 m below CD. A total area of approximately 1 100 000 m2 or 110 ha would be deepened by dredging, removing approximately 1 230 000 m 3 of material. The method of dredging is influenced by port operational constraints as well as the requirement that only one berth is non- operational at a time. The extent of the area to be dredged is outlined in Figure 3-5.
3.2.1 Characterisation of Material to be Dredged The basin contains both soft and hard material. Table 3-2 provides an overview of the types and approximate quantities of material that will be dredged. Table 3-2: Dredge material Type of material Quantity (m 3) % of total Soft material Gravel 37 977 3% Sand 512 691 40% Mud (finer than 0.063 mm) 398 760 34% Sub total soft material 949 428 77% Soft rock 192 944 16% Hard rock 86 956 7% Sub-total rock 279 900 23% Total 1 229 328 100% Source: Transnet Soft material, mostly consisting of sand and mud, as well as soft rock accounts for the overwhelming majority of material that is to be dredged, while hard rock accounts for approximately 7% of material to be removed. Once removed from the bottom of the basin, the dredged material is expected to expand (or “bulk up”).
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Figure 3-5: Extent of area to be dredged Source: Transnet, adapted by CSIR (2006a)
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Figure 3-6 indicates the current thickness of soft sediment within the Ben Schoeman Dock Basin. The figure clearly shows that in several areas soft sediment is less than 1.5 m thick.
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Entrance to Ben Schoeman Dock
Figure 3-6: Sediment thickness Source: CSIR The nature of the contaminants and level of contamination of the material to be dredged was investigated during 2005 and 2006. The sampling found that in the surficial sediment (CSIR, 2006a and CSIR, 2006b):
• Individual London Convention (LC) Annex II trace metal concentrations exceed special care (action level) thresholds at all sampling points along the periphery of the basin but not at those towards the centre of the basin;
• Cadmium and mercury, both LC Annex I contaminants, exceed the special care (action level) threshold at three (cadmium) and seven (mercury) of the 18 sampled sites respectively;
• For both LC Annex I and II individual trace metal concentrations most of the exceedances are close to the lower end of the defined thresholds;
• The combined LC Annex I and II trace metal concentrations exceed the special care thresholds in all cases except at one sampling location, which is however located approximately 11 m outside of the proposed dredge area for which prohibition levels are exceeded;
• The concentrations of the individual PAH (polycyclic aromatic hydrocarbons) compounds in surficial sediment is low; and
• Total aliphatic and petroleum hydrocarbon (TPH) concentrations are consistently below screening level thresholds.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 28 The dredge spoil is thus characterised by trace metal concentrations higher than the London Convention special care (action level) thresholds 15 and BCLME (Benguela Current Large Marine Ecosystem) threshold effect levels (TEL) 16 , although they do not exceed the prohibition thresholds 17 (i.e. levels above which they may not be disposed of at sea). The subsurface sediments lying 0.9 m and more below the seabed of the BSD show significantly less contamination than the higher-lying sediment layers (CSIR, 2006a). This is consistent with the assumption that modern anthropogenic sources are responsible for the observed contamination in the surficial sediment layers.
3.2.2 Drilling and Blasting There is approximately 87 000 m 3 of hard rock in the Ben Schoeman Dock Basin that may require blasting before it can be dredged and disposed. It is proposed that 'small parcel' blasting will be used, minimising environmental risks. This entails the drilling of blast holes in an underwater formation and loading them with explosives to form column charges which shatter the rock. This method of blasting also takes account of financial considerations, the confined environment of the Port of Cape Town in order to avoid surface blasting due to the uncontrolled nature and severe environmental impacts of surface explosions. Underwater blasting does not result in excessive noise levels. The blasting method entails the following:
• A specially designed drilling pontoon is positioned for drilling;
• Mobile percussion or rotary drills on the pontoon drill the blast holes in the required pattern;
• Blast holes are charged with explosives and suitable priming and timing equipment; and
• The pontoon is retired and blast holes are detonated sequentially in a so-called “ripple charge” procedure according to a specific time delay sequence. For the above blasting activities, a drill programme is determined. The programme specifies factors such as the blast hole pattern, maximum explosive charge per delay and firing pattern of the charges (Entech and CSIR, 2006).
3.2.3 Dredging Equipment The dredging of the Ben Schoeman Dock may utilise different dredging equipment, including: 1. Trailing Suction Hopper Dredger (hydraulic dredger); 2. Cutter Suction Dredger (hydraulic dredger); and 3. Back Hoe Dredger (mechanical dredger).
15 Concentrations of substances at levels which may result in minor environmental effects, but below the level which would result in acute or chronic effects on human health of sensitive marine organisms. 16 The water quality threshold value below which in situ adverse biological effects are considered unlikely. 17 Concentrations of substances at levels which will cause significant deleterious biological responses, and may thus not be disposed of at sea.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 29 The equipment is described in more detail in the following sections. The dredge equipment utilised will depend on the availability of equipment at the time of dredging and can thus not be specified at this stage.
3.2.3.1 Trailing Suction Hopper Dredger A Trailing Suction Hopper Dredger (TSHD) operates very much like a floating vacuum cleaner. It sails slowly over the area to be dredged filling its hopper, contained within its hull, as it proceeds. The pumps are usually inboard, but may be fitted in the trailing suction pipe. On approach to the dredge area, the suction pipe is swung overboard and/or lowered below the surface of the water. The intake end of the suction pipe is fitted with a “draghead”, which maximises the concentration of material entrained from the seabed. On completion of loading the dredger sails to the disposal site where the cargo can be discharged, either by opening the doors or valves in the hopper bottom, by using the dredging pump to deliver to a shore pipeline (not applicable in this case), or directly to shore by using a special bow jet (not applicable in this case). This last technique is known as rainbowing and is commonly used for reclamation and beach nourishment (see Figure 3-7 and Figure 3-8).
Figure 3-7: Schematic drawing of a Trailing Suction Hopper Dredger Source: Transnet
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 30 TSHD’s operate best by skimming off layers of material in long runs, such as might be found in channel dredging. They are unable to get into corners and can be difficult to manoeuvre in confined spaces close to quays and jetties. They are not very effective on hard materials such as the stiffer clays, but can dredge rock which has been blasted, or loosened by a cutter dredger. These dredgers are very efficient for the materials they can handle effectively. Most harbour maintenance dredging today is carried out by trailers, and they are also employed for capital projects, pipe trenching and reclamation.
Figure 3-8: Representative photo: Trailing Suction Hopper Dredger Source: www.dredging.com
3.2.3.2 Cutter Suction Dredger A Cutter Suction Dredger (CSD) is a dredger which makes use of a cutter head to loosen the material to be dredged. It pumps the dredged material via a pipeline ashore or into barges. Cutter suction dredgers operate by swinging about a central working spud - a large pole (known as a spud) that can anchor a ship while allowing a rotating movement around the point of anchorage - using moorings leading from the lower end of the ladder to anchors. By pulling on alternate sides the dredger clears an arc of cut, and then moves forward by pushing against the working spud using a spud carriage (see Figure 3-9 and Figure 3-10). A generally smooth bottom can be achieved, and modern instrumentation allows profiles and side slopes to be dredged accurately. The cutter head can be replaced by several kinds of suction heads for special purposes, such as environmental dredging.
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Figure 3-9: Schematic drawing of a Cutter Suction Dredger Source: Transnet
Figure 3-10: Representative photo: Cutter Suction Dredger Source: www.dredging.com
3.2.3.3 Backhoe Dredger A backhoe dredger (BHD) is a dredger, moved on anchors or on spud poles. Small BHD’s can be track mounted and work from the banks of ditches. In the case of dredging the berths at Port of Cape Town, a land-based or marine-based BHD can be used. A backhoe dredger is a hydraulic excavator equipped with a half open shell. This shell is filled moving towards the machine. Usually the dredged material is loaded onto barges. This machine is mainly used in harbours and other shallow waters (see Figure 3-11 and Figure 3-12).
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Figure 3-11: Schematic drawing of a Backhoe Dredger Source: Transnet
Figure 3-12: Representative photo: Backhoe Dredger Source: www.dredging.com In terms of the use of a BHD in the basin deepening and berth upgrade activities, there are aspects of the dredger which are well suited to this task:
• Unlike other types of dredgers, it does not require anchors or mooring lines whose use could prove problematic given the limited space of the BSD;
• The backhoe dredger has a lower production rate compared to the two alternative pieces of dredging equipment. An aspect of the berth deck alterations is a scour protection trench required along the north-eastern quayside of the BSD, which can only be dredged in limited stages. The BHD is thus suited to this type of operation; and
• Since the backhoe dredger is able to remove some of the rock, its use could assist with the limitation of rock blasting (Entech and CSIR, 2006).
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 33 3.2.4 Dredging Options The dredging equipment discussed in Section 3.2.3 can be used for the proposed deepening of the BSD in a number of ways and combinations. The most likely dredge options are discussed below: 1. A combination of a CSD with a dredge rate of approximately 100 000 m3 per week and BHD with a dredge rate of either 10 000 m 3 or 20 000 m 3 per week. 2. A combination of TSHD with a dredge rate of approximately 100 000 m 3 per week and BHD with a dredge rate of either 10 000 m 3 or 20 000 m 3 per week. 3. BHD(s) only with a dredge rate of between 10 000 m 3 and 20 000 m 3 per week.
3.2.4.1 Option 1: Cutter Suction Dredger (CSD) and Backhoe Dredger (BHD) This option assumes a continuous operation of the CSD for approximately 12 weeks during the assumed 136 week total duration of the dredging operations. The BHD would operate intermittently for a total of about 8 to 16 weeks, depending on the dredge rate, to keep three of the Berths 601 to 604 operational at all times. The CSD would remove the bulk of the material in the Ben Schoeman Dock while the BHD is used in the areas that are more difficult to access and to dredge berths 601 to 604 (see Figure 3-13) (CSIR, 2006b). The CSD is assumed to dredge 100 000 m 3 (in situ volume) of material a week, while two dredging rates of between 10 000 m 3 and 20 000 m 3 ( in situ volume) a week have been assumed for the BHD (CSIR, 2006b) (see Table 3-3). Table 3-3: Dredge rates for Option 1 (CSD and BHD) Volume to be dredged Approximate Dredging Dredge Rate Method (m 3) * 1 duration (m 3/week) Higher Dredge Rate Scenario CSD 1 210 000 12 weeks ~ 100 000 BHD 143 000 8 weeks ~ 20 000 Lower Dredge Rate Scenario CSD 1 210 000 12 weeks ~ 100 000 BHD 143 000 16 weeks ~ 10 000 *1 in-situ volumes that include an additional 10% “safety margin”.
Source: CSIR (2006b)
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Figure 3-13: Indicative dredging timelines: Option 1 (above – higher BHD dredge rate, below – lower BHD dredge rate) 18 Source: CSIR (2006b)
18 Note: dredge areas in this figure are indicative only and are not to scale. Volume are in situ that include an additional 10% “safety margin”
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 35 3.2.4.2 Option 2: Trailing Suction Hopper Dredger (TSHD) and Backhoe Dredger (BHD) This option assumes a continuous operation of the TSHD for approximately 10 weeks during the assumed 136 week total duration of the dredging operations. The BHD would operate intermittently for a total of about 16 to 32 weeks, depending on the dredge rate, to keep three of the Berths 601 to 604 operational at all times. The TSHD would remove the bulk of the soft material mostly in the outer area of the Ben Schoeman Dock, while the BHD will be used in the areas that are more difficult to access and to dredge berths 601 to 604 (see Figure 3-14) (CSIR, 2006b) including all rock, treated or untreated. The TSHD is assumed to dredge 100 000 m 3 (in situ volume) of material a week, while two dredging rates of 10 000 m 3 and 20 000 m 3 ( in situ volume) a week have been assumed for the BHD (CSIR, 2006b) (see Table 3-4). Table 3-4: Dredge rates for Option 2 (TSHD and BHD) Volume to be Approximate Dredging Dredge Rate Method dredged (m 3) * 1 duration (m 3/week) Higher Dredge Rate Scenario TSHD 1 045 000 10 weeks ~ 100 000 BHD 308 000 16 weeks ~ 20 000 Lower Dredge Rate Scenario TSHD 1 045 000 10 weeks ~ 100 000 BHD 308 000 32 weeks ~ 10 000 *1 In-situ volumes that include an additional 10% “safety margin”. Source: CSIR (2006b)
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Figure 3-14: Indicative dredging timelines: Option 2 (above – higher BHD dredge rate, below – lower BHD dredge rate) 19 Source: CSIR (2006b)
19 Note: dredge areas in this figure are indicative only and are not to scale. Volume are in situ that include an additional 10% “safety margin”
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 37 3.2.4.3 Option 3: Backhoe Dredger only This option assumes the continuous operation of one BHD (potentially supplemented with a land- based dredger or another BHD), which would operate for approximately 68 – 136 weeks, depending on dredge rates. Two dredging rates of 10 000 m 3 and 20 000 m 3 ( in situ volume) a week have been assumed for the BHDs (CSIR, 2006b) (see Table 3-4 and Figure 3-15). Table 3-5: Dredge rates for Option 3 Volume to be Approximate Dredging Dredge Rate Method dredged (m 3) * 1 duration (m 3/week) Higher Dredge Rate Scenario BHD 1 353 000 68 weeks ~ 20 000 Lower Dredge Rate Scenario BHD 1 353 000 136 weeks ~ 10 000 *1 In-situ volumes that include an additional 10% “safety margin”.
Source: CSIR (2006b)
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Figure 3-15: Indicative dredging timelines: Option 3 (above – higher BHD dredge rate, below – lower BHD dredge rate) 20 Source: CSIR (2006b)
20 Note: dredge areas in this figure are indicative only and are not to scale. Volume are in situ that include an additional 10% “safety margin”
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 39 For the purposes of this EIA, the possibility of making use of any of the above dredge options has been considered, and in each case the “worst case” scenario assessed.
3.2.5 Transport and Disposal of Dredge Spoil The material dredged from the BSD would be loaded by the dredge equipment onto a hopper barge lying alongside in the BSD (or, in the case of the TSHD, into the hopper contained within the TSHD’s hull). While loading the hopper barge with dredged material, the already loaded sediment within the hopper sinks to the bottom of the barge and separates from the water that was loaded together with the dredged material. The remaining water is called ‘lean mixture’ or ‘tailings’ and contains reduced sediment concentrations. Should it be allowed to dispose of this water from the hopper barge within the BSD, more space will be available in the barge to load dredged sediment and fewer trips will be required, resulting in significant cost savings. The procedure of disposing the water is called ‘lean mixture overboard’. However, should lean mixture overboard be allowed this will increase the sediment concentrations in the hopper barge and potentially increase impacts from within the port and on beneficial uses in the port and surroundings. For the purposes of this assessment, it has been assumed that lean mixture overboard will be allowed21 . Once filled, the hopper barge sails to a suitable dredge disposal site offshore, where the dredged material is dumped in the water 22 . The precise method of dredge spoil disposal will depend on which of the dredging options discussed in Section 3.2.4 is employed. The required disposal scenarios for the different options are summarised in Table 3-6. Table 3-6: Spoil disposal rates for dredging options 1 – 3 Total no of Daily no of Volume to be Dredging Nominal hopper Method hopper hopper dredged (m 3) * 1 duration barge size (m 3) loads loads Option 1 – CSD and BHD CSD 1 210 000 12 weeks 3 500 672 8 BHD 143 000 8 -16 weeks 2 500 112 2 Option 2 – TSHD and BHD TSHD 1 045 000 10 weeks 4 800 420 6 BHD 308 000 16-32 weeks 2 750 224 2 Option 3 – BHD BHD 1 353 000 68-136 weeks 2 750 952 2 *1 In-situ volumes that include an additional 10% “safety margin”. Source: CSIR (2006a) Each dumping operation should be such that the sediment is distributed over the entire dredge disposal site to avoid creating dump mounds. It is expected that the seabed will be raised by on average approximately 30 cm at the disposal site by the disposal of dredge spoil (CSIR, 2006b)
21 This is considered the “worst case” scenario in terms of impacts on the marine environment. 22 See Section 4 for a discussion of the selection of suitable disposal sites.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 40 although the possibility of mounds with peak heights of 60 to 70cm height are anticipated. This would represent a decrease in water depth of less than 2% for a site of 40 depth, and approximately 1% for a site of 70m depth, based on anticipated mount heights. At the dump site, most of the material will be transferred to the seabed by convective descent of the sediment mass. It has been conservatively assumed that 10% of the fine sediment ( i.e. mud) will initially enter the water column as suspended load, while 90% will be deposited on the seabed. The material deposited on the seabed may subsequently be re-suspended during strong wave or current events and transported away from the dumpsite as a turbid plume (CSIR, 2006b).
3.3 Berth Upgrades The existing berth decks comprise concrete block walls topped with in-situ reinforced concrete capping, which contains two service tunnels. The founding conditions are variable, ranging from hard rock beneath a portion of Berth 601 to poor material which was selectively replaced beneath the foundations of portions of Berths 602-604. The proposed alteration to Berths 601 to 604 includes (also see Figure 3-16):
• Constructing a concrete suspended deck quay structure supported on piles (columns) extending approximately 10m beyond the existing quay face (into the basin) at each of the four berths; and
• Constructing a single crane rail at a distance of approximately 30 m from the existing landside crane rail on the existing quay to enable the use of new super post Panamax container gantry cranes.
3.3.1 Berth Deck Alteration Equipment The equipment that will be used to construct the proposed extension of the berths includes, but is not limited to:
• Piling rig with hydraulic hammer(potentially from a barge);
• Casings;
• Material delivery wagons (to deliver concrete, formwork and reinforcement);
• Waste Disposal trucks;
• Drilling rig;
• Crawler crane; and
• Barge or barge mounted crane (possibly).
3.3.2 Berth Deck Alteration Method The method of construction of the decks of Berths 601 to 604 is influenced by port operational constraints as well as by the sequencing of the berth deck upgrades, which will be planned so that only one berth is non-operational at a time.
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Figure 3-16: Proposed deck upgrades
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2006 SRK Consulting BSD Deepening EIR Page 42 The method of construction involves the following:
• Dredging a scour protection trench adjacent to the quay wall. This will require drilling and blasting of rock at berth 601 and dredging of the coarse and fractured blast material. A backhoe dredger can be utilised, but some soft material could be dredged using a land-based grab (see Section 3.2.4).
• Installing the piles, which are necessary to support the deck extension, approximately 7 m from the cope line. It is envisaged that driven tube piles will be used, because a pile permanently encased in steel tubes is ideal for marine work. Pile installation can be either bottom- or top- driven. The bottom-driven method involves the following:
− The tubes are placed over the pile position and a measured quantity of semi-dry concrete, a “plug”, is discharged into the tube.
− A cylindrical hydraulic hammer which operates within the bore of the tube is used to compact the concrete, which is then topped with another plug until the tube is full. In so doing, the hydraulic hammer drives down the plug which drives down the closed bottom of the steel tube. The next section of tube is then welded on top of the leader tube, and consecutive tubes as required.
− The bottom-driven method is better suited to hard driving conditions but places more stress on the steel tube, increasing the risk of the tube splitting. The top-driven method entails the following:
− The hydraulic hammer drives the top end of the steel tube, and as the tube drives into the ground, subsequent tubes are welded on until the founding stratum has been reached. Top- driving places less stress on the steel tubes, but is not as efficient in hard driving conditions as a large proportion of the hammer’s energy is absorbed by the tube itself. Top-driving is also noisy and should be avoided in built-up residential and commercial areas.
− Mounting a drilling rig on top of the installed piles to core out the inside for the insertion of rebar and the casting of concrete. In both cases, once the tube is driven, a reinforcing cage is lowered into position and the shaft of the pile concreted using a high slump self-compacting mix.
• Laying down a 1 m thick scour protection mattress of 50 kg – 100 kg of rock.
• Extending the existing quay wall by constructing a 10 m reinforced-concrete deck extension to be supported by the installed piled foundations. This can be done by casting the concrete in situ , or by using pre-cast concrete. Casting the concrete in situ involves the following:
− Bracing the piles, attaching temporary formwork to the top of the piles and installing temporary pre-fabricated shuttering spanning between the piles;
− Completing the crane rail beam by putting the rebar in place and casting the concrete; and
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 43 − Re-using the formwork, installing temporary shuttering between the crane rail beam and the existing cope line, putting rebar in place and casting concrete to form the deck. Using pre-cast concrete involves the following:
− Bracing the piles and attaching temporary formwork to the top of the piles to form hollow pile-cap supports;
− Forming a channel between the pile caps by installing a pre-fabricated concrete shuttering system;
− Forming a permanent crane rail support by stitch-up, rebar and casting of concrete; and
− Using permanent formwork, placing the pre-fabricated concrete deck between the crane rail beam and the cope line, fixing the rebar and casting the concrete.
3.3.3 The Installation of New Cranes The BSD currently accommodates four Demag and two Noell ship to shore cranes (Figure 3-17 to Figure 3-19), which are located on rails running parallel to the edge of Berths 600 – 604. The cranes are rail-mounted and can be moved on the rails along the berths as required to load and offload containers onto and from vessels moored along the berths.
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Figure 3-17: Existing Cranes at Ben Schoeman Dock
Figure 3-18: Diagram of Existing Crane – Noell To accommodate the larger container vessels that will be utilising the Port, larger ship-to-shore cranes are required. Initially, the four Demag cranes will be replaced by six new super post pananmax cranes, resulting in a total of eight working cranes. The intention is to eventually replace these existing cranes with up to a total of 12 new cranes to suit the demand. The dimensions of the new cranes are depicted in Figure 3-20.
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Figure 3-19: Diagram of proposed new Cranes The approximate dimensions of the existing and proposed future cranes are indicated in Table 3-7. Table 3-7: Approximate Crane Dimensions Crane Approximate Height Approximate Length (with jib in upright position) Demag 75 m 90 m Noell 92 m 105 m Proposed new cranes 99 m 105 m Source: Transnet To enable the use of these new super post Panamax container gantry cranes, a single crane rail at a distance of approximately 30 m from the existing landside crane rail needs to be constructed.
3.4 Project Timeline The upgrading of the berth structures is scheduled to take place in phases over a four year period, commencing in the later half of 2007 (subject to environmental authorisation) and completing during the latter part of 2011. The first phase comprises the construction of a temporary crane rail for berths 603 and 604. The second phase entails the proposed upgrade of the berths and deepening of the dock. The anticipated duration of dredging for the different dredging options is discussed in Section 3.2.4. In most cases, the activities are expected to continue for a total of 136 weeks, or approximately 2.6 years, alternative dredge equipment operating intermittently for shorter periods within that total duration. The dredging activities are anticipated to commence in January 2008 (subject to environmental authorization) and complete during the latter part of 2010.
3.5 Contractors’ Yard It is proposed that the Culemborg site is to be used as a construction contractors’ storage area(contractor’s yard) for the duration of the project, as the ongoing port operations limit the available space at the Ben Schoeman Dock.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 46 This site measures 1.8 ha and is situated on the Cape Town Foreshore, east of Lower Church Road between Woodstock and the Port and to the south of the N1 Freeway. Figure 3-20 indicates the position of the Culemborg site in relation to the BSD.
Figure 3-20: Position of Culemborg Site, to be used as Contractors Yard Source: Transnet It is expected that all movements of construction material by truck will take place via Marine Drive, Container Road and Duncan Road to the Contractors’ Yard. Access to the yard will be opposite the Elliot Basin access via the existing rail culvert underneath the N1, which provides a link between the Spoornet commuter and Port rail lines (HHO Africa, 2006a) and is shown in Figure 3-21. This requires that a temporary gravel road be constructed along the western barrel of the culvert and pre-cast concrete slabs be constructed across the railway lines. Traffic movement crossing the commuter and port rail lines will need to be regulated relative to freight train movements. A traffic marshal in communication with train operators at the central train control centre will ensure this regulation. A four-way stop controlled intersection is proposed at the intersection of the Contractors’ Yard access road and Duncan Road.
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Figure 3-21: Culvert underneath N1 providing access to the Culemborg Site It is assumed that all material delivered for the BSD project will be transported to the construction site through the Contractors’ Yard except for scour protection rock that will be delivered directly to the construction site (HHO, 2006a). The Contractor’s Yard will be used for the:
• Storage of construction materials;
• Housing of a concrete batching plant;
• Temporary storage of fuel required for construction equipment (in above-ground fuel storage tanks); and
• Fabrication of required elements such as pre-casting of concrete. The equipment that is assumed to be operating at the Contractors’ Yard includes (DDA, 2006):
• Concrete Mixing Truck;
• Concrete Batching Plant;
• Truck offloading facilities;
• Front-end loader;
• Welding equipment; and
• Small cranage.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 48 The site will require organisation and infrastructure, which will entail the following:
• Preparing the surface area of the site by laying down a geotextile followed by a levelling layer of stone;
• Erecting fencing and lighting for security;
• Connecting the site to the municipal services system, e.g. water and electricity;
• Providing a temporary site office and ablution facilities for security and construction personnel;
• Converting a three-way traffic intersection at Duncan Road to a four-way intersection using signage and road markings to provide access for construction traffic from the Contractors’ Yard to BSD; and
• Closure of the road on the north-western side of this intersection to public traffic, as indicated on Figure 3-23. Material employed for the alteration of the berth deck will be sourced from commercial sources. Waste produced during construction will include hard rock from the basin invert, trimmings from piles and existing concrete aggregate from resurfacing works. Waste will be disposed of at a suitable landfill site or, where possible, will be crushed so that the crushed aggregate can be re-used. Management of the contractors’ camp, and construction activities will be undertaken in accordance with a Construction Phase Environmental Management Plan, in order to ensure that potential environmental impacts as a result of construction activities are minimised. Note: It has recently been indicated by City of Cape Town officials that some road proposals identified as part of the N1 Corridor upgrading project, may be implemented as part of a package of infrastructure projects in preparation for World Cup 2010. This will necessitate the Contractors’ Yard being relocated to another site within the port area. Two possible areas which may be considered (although others may be identified) include a hard standing area adjacent to Panama Jack’s restaurant and an area in the marshalling yard east of Ben Schoeman Dock.
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Figure 3-22: Proposed Access to Contractor's Yard
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 50 4 Project Alternatives In terms of the EIA regulations (Regulation 6 (1) (d) GN No. R1183, dated 5 September 1997) and NEMA, the applicant is required to demonstrate that alternatives to the proposed project have been described and considered in sufficient detail.
4.1 “No Development” Alternative The “No Development” (i.e. “do nothing”) alternative implies that none of the proposed development components are implemented. For the purposes of this study this means that neither the upgrade of Berths 601, 602, 603 and 604 nor the deepening of the BSD basin takes place. As such, the environmental status quo in respect of the biophysical environment would be maintained. However, as described in Section 3.1, shipping lines use increasingly bigger cargo vessels that require deeper basins and ship-to-shore cranes with wider reach. Without modifications to the Port, these vessels would not be able to enter the Port of Cape Town due to inadequate water depth and berth infrastructure. Cargo vessels currently provide important business to the Port of Cape Town and a reduction in the number of vessels using the Port as a result of inadequate port infrastructure is likely to threaten the global competitiveness of the Port, with a knock-on effect on other industrial and business areas that depend on income from port activities.
4.2 Project Aspect Alternatives The Scoping Report (Shangoni, 2005) identified and considered a number of alternatives for aspects the proposed berth deepening project. Table 4-1 shows these alternatives. Options that were screened out during the Scoping Phase are shaded in light grey. The motivation for excluding these options is provided in the Final Scoping Report (Shangoni, 2005), which was accepted by DEA&DP in June 2005 and informed the scope of the EIA phase conducted by SRK. As such, the exclusion of these options has been approved by the authorities and the motivations are not laid out again in detail in this EIR. Alternatives screened out after the Scoping phase, but before the EIA phase, are shaded in darker grey.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 51 Table 4-1: Project alternatives identified during scoping Aspect Alternatives Current Status Project No Development alternative Assessed in EIA phase Location Ben Schoeman Dock (Port of Cape Town) Assessed in EIA phase Duncan Dock (Port of Cape Town) Screened out during Scoping Port of Saldanha Screened out during Scoping Berth Alteration Retain the existing quay structure Screened out during Scoping Extend deck by 10 m into the basin Assessed in EIA phase Extend deck by 20 m into the basin Screened out during Scoping Spoil Disposal Land-based disposal of sediment Screened out before EIA Phase Deepwater disposal (40m + depth) Assessed in EIA phase Near-shore disposal (~15 m depth) Screened out before EIA Phase Surf zone disposal (3 m – 5 m depth) Screened out before EIA Phase Blasting Surface blasting Screened out during Scoping Buried multiple small charges Assessed in EIA phase Source: adapted from Shangoni (2006)
4.2.1 Project Aspect Alternatives Screened Out After the Scoping Phase All dredge spoil disposal alternatives identified during the Scoping phase and listed in Table 4-1 were considered to be potentially viable in the Final Scoping Report. However, three of the four dredge spoil disposal alternatives were screened out following the submission of the Final Scoping Report and before the start of the EIA phase. The alternatives excluded at this stage are: 1. Land-based disposal of sediment; 2. Near-shore disposal of sediment; and 3. Surf zone disposal of sediment. This approach and the motivations for screening out these disposal options were detailed in the Plan of Study for EIA submitted by SRK in September 2006. The Plan of Study, and hence the approach, were accepted by DEAT in October 2006. The motivations for exclusion of these alternatives in the EIA are detailed below.
4.2.1.1 Land-based disposal of dredge spoil Two land-based disposal options for dredge spoil were considered during Scoping: 1. Disposal of dredge spoil that is contaminated and not compliant with the London Convention in a hazardous waste landfill site, as such dredge spoil cannot be disposed of at sea; and 2. Use of rock dredged from the BSD as construction material in the Container Terminal Expansion (CTE) project. These alternatives have been screened out following the Scoping phase and are not assessed in detail in the EIA phase for the following reasons:
• Compliance of sediment with London Convention: The analysis of sediment to be dredged has shown that the material’s contamination levels lie below the prohibition levels defined in the London Convention (CSIR 2006b, also see Section 3.2.1 of this EIR). As such, the dredge spoil can be disposed of at sea and land-based disposal at a hazardous waste landfill is not required;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 52 • Separation of CTE and berth deepening projects: The CTE and berth deepening projects were linked and to be implemented in parallel when the Scoping phase for the berth deepening project was undertaken. This proposed parallel execution of the projects gave rise to the option of using dredged material from the BSD in the construction of the CTE. However, the two projects are independent of each other, and have since been separated. As such, the dredged material from the BSD is no longer required for the CTE project.
4.2.1.2 Near-shore and surf zone disposal of dredge spoil Although considered viable alternatives in the Scoping Report, there are a number of potential impacts associated with the disposal of dredge spoil at near-shore or surf zone disposal sites, which has led to the decision by Transnet to exclude these options from the EIA phase in favour of alternatives less likely to generate adverse impacts and public concern. These potential impacts, as identified during the scoping phase, include:
• Shoreline stability: Coastlines are dynamic in nature and reshape constantly as a result of current, wave and wind action. As such, there is concern that the disposal of sediment close to or on the shore may alter the existing sediment regime and wave and current patterns within Table Bay. This would lead to increased erosion or accretion of sediment in areas of Table Bay. As there are a number of developments close to the shore of the Table Bay, some already affected by erosion, the public also expressed significant concern about the potential alteration of the coastline;
• Health impacts: Specialists expressed concern that it would prove difficult to assess with confidence the potential health impacts from disposing the dredged sediment close to human receptors and recreational areas. It also became clear during the Scoping phase that this was of significant concern to the public; and
• Visual impacts: Visual impacts from disposing of sediment near or on the shore could result from turbidity plumes in the water and distinct deposits of differently-coloured sediment on the shore. The potential significance of these impacts is increased as the proposed disposal sites would be located near human receptors and recreational areas within a scenic beach landscape.
4.2.2 Project Aspect Alternatives Considered in the EIA Phase For all project aspects, one potentially viable alternative per aspect was retained and is assessed in more detail in the EIA phase. However, for the deepwater disposal of dredged sediments, three potential deepwater dredge disposal sites were identified in the EIA phase. These include:
• The dredge disposal site of the Port of Cape Town identified in CSIR (1991), located approximately 275 km from the Port of Cape Town at a water depth of 3 500 m;
• “Site 1”, located about 13 km from the Port of Cape Town at a water depth of approximately 65 m; and
• “Site 2”, located about 9 km from the Port of Cape Town at a water depth of approximately 40 m. These deepwater dredge disposal site alternatives are discussed in more detail in the sections below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 53 4.2.2.1 Dredge Disposal Site at 3 500 m Depth This site was identified by the CSIR in 1991 in its “First Report on The Situation of Waste Management and Pollution Control in South Africa” as a potential disposal site for dredge material from the Port of Cape Town. In this EIA for the berth deepening project, this site is not considered to be viable and was screened out as a potential disposal site for dredge spoil from the BSD for the following reasons:
• Economically unfeasible: As the site is located some 275 km from the BSD, hopper barges would take approximately one day for a return trip to the disposal site to dump dredged material. As such, significantly more resources in terms of hopper barges, fuel and personnel would be required for disposal of dredge spoil at this site than would be needed if spoil was disposed at a site located closer to the BSD. It is also likely that Trailer Suction Hopper Dredgers, providing the shortest duration of dredging operation, could not be used if disposal were to take place at this site (CSIR 2006d).
• Dispersal of sediment: Disposing dredge spoil at this site is also likely to result in a large dispersal of mud into the water column during disposal due to the long distance between water surface and seabed.
• Limited accessibility of site: The characterisation and monitoring of the site would be problematic, as its distance and great depth would require long trips and the use of specialised equipment that is costly and difficult to obtain.
4.2.2.2 Dredge Disposal Site 1 at 65 m Depth and Site 2 at 40 m Depth To identify two alternative deep water dredge disposal sites for consideration in this EIA, a number of criteria were applied. As far as feasible, a site was sought where (CSIR, 2006a):
• Seabed sediment composition is similar to that of the disposed material;
• Material is either retained in a discrete area (if sediment is of different composition than the general receiving environment) or allowed to disperse to facilitate habitat recovery;
• Impacts on biodiversity and/or rare and endangered species are limited;
• No existing sensitive areas are in the vicinity;
• Potential impacts on shoreline stability are avoided;
• Site characterisation is possible; and
• Disposal of dredge spoil is financially feasible, as significantly determined by the distance of the site from the dredged area. Based on an existing high resolution bathymetric chart of Table Bay, two sites with a seemingly sandy seabed composition were preliminarily selected for further investigation. The location of Site 1 (~13 km from the Port and ~65 m deep) and Site 2 (~9 km from the Port and ~40 m deep) is indicated in Figure 4.1. Each of these potential dredge disposal sites is approximately 3 km x 2 km, or 6 km 2, in size.
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Small Stormwater Outfalls
Industrial & Sewage Outfalls
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3760000 65000 60000 55000 50000 45000 Figure 4-1: Proposed dredge spoil disposal sites Source: Lwandle, 2006a The assumptions that were made about the composition of the seabed at both sites based on the bathymetric chart were subsequently confirmed by a second high resolution bathymetric chart that extends further west than the originally used chart (CSIR, 2006a). Side-scan sonar and single beam bathymetric surveys were conducted at Site 1 and Site 2 on 31 August 2006. The analogue side-scan record was used to select suitable grab sampling sites to collect seabed samples for site characterisation. At each sampling site, five replicate van Veen grab
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 55 samples were retrieved. The sampled sediment was analysed for granulometric (sediment particle size and texture) and chemical characteristics as well as for benthic macrofauna at the two sites, as required for the permit application in terms of the Dumping at Sea Control Act 73 of 1980 and the London Protocol 1996. Data from these surveys was also used to identify and confirm the suitability of the candidate sites for harbour dredge spoil disposal and to provide a baseline for the impact assessment (CSIR, 2006a). The geological and ecological characteristics of Site 1 and Site 2 thus determined are described in Chapter 5: Description of the Affected Environment (Sections 5.1.2 and 5.1.4). Site 1 and Site 2 were both deemed potentially viable for the disposal of dredge spoil from the BSD. Their suitability for disposal of dredged material in general and suitability relative to each other is assessed in Chapter 7: Assessment of Environmental Impacts.
4.3 Other Alternatives Considered in the EIA Phase Project implementation alternatives such as different dredging options making use of a combination of Trailing Suction Hopper Dredger, Cutter Suction Dredger and/or Backhoe Dredger, with different associated durations of dredging options, are described in Chapter 3: Project Description (Section 3.2.4).
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5 Description of the Affected Environment
5.1 Biophysical Environment
5.1.1 Climate The Cape Peninsula has a Mediterranean climate with well-defined seasons. The complex system of folded mountains which dominate the coastal plains of the Cape Peninsula, is the main physical feature which impacts the prevailing weather systems. Winter months extend from May to August and are considered mild, with a July average maximum temperature of 18°C and average minimum temperature of 7°C. The Western Cape is a winter rainfall area, with occasional rain during the summer season. Rain during this time is a result of large cold fronts originating over the south Atlantic Ocean which approach Cape Town from the northeast. Strong northerly and north-westerly winds, which may reach gale force, generally accompany these cold fronts. Due to the varied topography of the peninsula, average rainfall in particular places can vary between 600 mm and 2 500 mm per year. The average daily temperatures and rainfall figures for the Cape Peninsula during the winter months are provided in Table 5-1. Table 5-1: Average temperatures and rainfall during winter Month Average Daily Max Average Daily Min Average Monthly Temperature (°C) Temperature (°C) Rainfall (mm) May 20 9 69 June 18 8 93 July 18 7 82 August 18 8 77 Summer in Cape Town extends from November to March and is characterised by warm and dry conditions. The average January minimum temperature is 16°C and the average maximum temperature is 26°C, with strong South Easterly winds occurring throughout the season, often blowing continuously for several days. The South Atlantic high pressure cell which is situated off the south coast during this period, causes these wind conditions, which can exceed 30km/hr for more than 20% of the time. The average daily temperatures and rainfall figures for the Cape Peninsula during the winter months are provided in Table 5-2. Table 5-2: Average temperatures and rainfall during summer Month Average Daily Max Average Daily Min Average Monthly Temperature (°C) Temperature (°C) Rainfall (mm) November 24 13 14 December 25 15 17 January 26 16 15 February 27 16 17
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 57 5.1.2 Geology
Table Bay Table Bay is a log spiral bay anchored by rocky headlands at Mouille Point in the south and Blouberg in the north. The bay contains Robben Island and the economically important Port of Cape Town. The maximum water depth in the centre of the bay is approximately 35 m, increasing to 70– 80 m outside of a line between Mouille Point and the western shores of Robben Island (Figure 5-1) (Lwandle, 2006). The seabed is mainly covered by thin layers of sand but has areas of partly exposed bedrock. Fine sand is generally confined to the eastern nearshore region between Blouberg and the harbour. However, a tongue of fine sediments extends from the nearshore zone seaward to a depth of approximately 25 m between Table View and Rietvlei. Smaller pockets of fine sand are found at the bay entrance and on the eastern shore of Robben Island. Medium coarse sand covers the remaining areas of Table Bay, as indicated in Figure 5-2 (Lwandle, 2006). The major sources of the sand in Table Bay are seasonal (mainly winter) inputs from the Diep and Salt Rivers and local erosion of Malmesbury shales. There is no substantial sediment supply to the bay from longshore transport from the south. Sediment is transported out of Table Bay by local wave and storm driven transport. The overall residence time for surficial sediments is estimated at 2-3 years (Lwandle, 2006).
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SITE 2
SITE 1
Figure 5-1: Bathymetry of Table Bay Source: Lwandle, 2006a
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Very Fine Sand (0.063-0.125mm) Fine Sand (0.125-0.250mm)
Medium Sand (0.250-0.500mm) Coarse Sand (0.500-1.0mm)
Very Coarse Sand (1.0-2.0mm) 3740000 Bedrock
Blouberg Rocks Robben Island
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0 km 2.5 km 5 km 3760000 65000 60000 55000 50000 45000 Figure 5-2: Sediment and Bedrock Distribution in Table Bay Source: Lwandle, 2006a The shoreline of Table Bay (see Figure 5-3) from Blouberg to Mouille Point consists of 3 km of rocky shore (at Blouberg and at Mouille Point), 13 km of sandy beach (between Blouberg and Table Bay harbour) and 4 km of artificial shore protection and breakwaters comprising the Port of Cape Town. Robben Island has a total shoreline of 9 km, of which 91% is rocky (Lwandle, 2006).
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Non-breeding Seal Colony White Mussel Beds Intertidal Sandy Shores Intertidal Rocky Shores Bank Cormorant Colony African Penguin Breeding Colony Kelpbeds Bloubergstrand
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Figure 5-3: Shoreline features and key faunal populations in Table Bay Source: Lwandle, 2006a
Port of Cape Town The current depth of the Ben Schoeman Basin varies between 10 m below CD in the eastern part of the basin near Berth 600 and 15 m below CD. Surficial sediments comprise:
• Dark grey, very loose to loose silty sand (equivalent spherical diameter particle size range <2.00mm - > 0.063mm); and
• Dark grey to black, soft sandy silt sediments, mainly mud (< 0.063 mm) with a small component of gravels (> 2.00 mm). The distribution varies throughout the dock basin, but the average composition is 43% – 50% sand, 21% – 44% mud and 5% – 19% gravel. The thickness of these sediments is typically 1 to 2 m (CSIR,
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 61 2006a). The presence of mud, silt and clay sized particles in the surficial sediments indicates that areas within the Ben Schoeman Dock basin are depositional in nature. This is expected, as harbours are usually located in quiet water areas so that shear stresses at the sea bed would be low, allowing fine material to deposit on the seabed. The variable thickness of the surficial sediment layer may be attributable to previous dredging and construction activities that altered the depth of the coarser material underlying the surficial sediments. Initial construction activities associated with the Ben Schoeman Dock occurred in the early 1970s, so that sediments would have been accumulating then (CSIR, 2006a). The material underlying the surficial sediments consists of:
• Very stiff silt and sandy silt from residual greywacke and shale of the Tygerberg Formation; and
• Very soft rock to hard rock shale and greywacke at depths ranging from 0.3 m to 7.05 m below the seabed (CSIR, 2006a). Rock covers approximately 35,000 m² in the south-eastern corner of the Ben Schoeman Dock.
Proposed Disposal Sites Two potential sites for the disposal of dredge material were identified during this study. On the basis of a side-sonar scan conducted in August 2006, a high resolution bathymetry chart and sampling results it was established that Site 1 is covered by sediment rather than rock. The sediment consists predominantly of sand with an admixture of mud. The variability of sampled sediment across the site is low, indicating that this site is relatively uniform. The seafloor becomes rocky to the west and sandy to the north-west of Site 1 (CSIR, 2006a; CSIR, 2006b). Site 2 consists of a small patch of sand surrounded by rocky reefs (CSIR, 2006b). Sediments consist predominantly of sand. Compared to Site 1 there is very little mud at Site 2 but a higher proportion of gravel-sized particles. Variability of sampled sediments across the site was high, indicating that the composition of the seafloor at Site 2 is less uniform than at Site 1. Ripples on the seabed also suggest a higher degree of sediment mobility at Site 2 (CSIR, 2006a). Trace metal concentrations in sediments measured at both sites are low and well within accepted thresholds. Sediment samples at Site 1 show higher trace metal concentrations than those at Site 2, which may be attributed to the presence of clay minerals at Site 1. The trace metals appear to be lithogenic in origin and may be representative of natural background concentrations in the geological setting of Table Bay (CSIR, 2006a).
5.1.3 Oceanography Table Bay is located within the southern Benguela upwelling system and its circulation and water properties are characteristic of the region. Water movement within the bay is primarily wind-driven, with shelf currents further offshore and tides playing a minor role. Wave-driven flows have an important effect in the nearshore. There are significant differences in the water conditions of the bay between summer and winter. In summer , wind from a south-easterly direction results in currents that flow northwards in an anti- clockwise motion within the bay. Upwelling cold water (9 - 13 °C) invades Table Bay from the Oudekraal upwelling centre south of Table Bay, resulting in generally shoreward bottom flows. Water temperatures can increase rapidly to more than 20 °C during relaxation phases of the
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 62 upwelling cycle as water flows into Table Bay from the north and north-west. Upwelling and solar heating in summer leads to a highly stratified water column (CSIR, 2006a). In winter , wind from a north/north-westerly direction drives water towards the south, producing a slight clockwise motion. Winter seawater temperatures are more uniform than in summer and fall into the narrow range of 14 - 16 °C, as there is no upwelling of cold water and strong mixing of water columns during storms (CSIR, 2006a). Typical wind-driven surface current velocities are between 20 and 30 cm/s. Bottom current velocities reach less than 5 cm/s. Recent studies showed comparatively short residence times for surficial sediments in Table Bay, suggesting that the main driver for sediment turnover are episodic winter storms that probably also flush the waters of the bay. Salinity in Table Bay appears to be quite uniform and ranges between 34.7 and 35.3 ppt. Two rivers, the Diep and Salt River, flow into Table Bay, lowering the salinity in the vicinity of the discharge area (CSIR, 2006a).
5.1.4 Marine Ecosystem
Table Bay The marine ecosystems in Table Bay comprise seven different recognisable ecological habitats , each supporting a characteristic biological community:
• Sandy beaches, extending from the Salt River mouth north past Blouberg;
• Rocky shores, at Blouberg Rocks and Robben Island and extending south of the harbour past Sea Point;
• Artificial surfaces of the harbour itself plus the shore protection extending towards Salt River;
• Subtidal sand substrata;
• Subtidal rock substrata in the bay;
• Water body in Table Bay; and
• Water body in the Port of Cape Town. The habitats and water upwelling process in Table Bay support well-developed biological communities that are typical of the west and south coast regions of the Western Cape. They include pelagic (e.g. pilchards and anchovy) and demersal (e.g. hake and kingklip) fish stocks, nearshore stocks (e.g. linefish, rock lobster and abalone), mammals (e.g. seals and whales) and seabirds (e.g. penguins, gannets and cormorants) (Lwandle, 2006a). Table Bay does not appear to be critically important for marine fauna as either a foraging or breeding area or for the fishing industry. Exceptions are endemic seabirds that occur in the bay, such as the Bank Cormorants and African Penguin, which feed and breed in Table Bay. Both species are considered vulnerable in terms of the IUCN criteria. The African Black Oystercatcher is classified as near-threatened (Lwandle, 2006a). There are resident, semi-resident and migrant cetaceans (e.g. dolphins and whales) in Table Bay. The most common is the Southern Right Whale, which seasonally migrates into South African waters between May – October/November and is regularly sighted in Table Bay. Southern Right Whales are classified as Vulnerable under the IUCN criteria (Lwandle, 2006a).
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 63 Four species of seals are found around the West Coast. The Cape Fur Seal is the most common in Table Bay but has no breeding colonies there. A historical seal colony at Robben Island was destroyed by disturbance and sealing in the early 20th century. Other, far less common, seal species include the Subantarctic Fur Seal, the Leopard Seal and the Southern Elephant Seal (Lwandle, 2006a). Table Bay is a receiving environment for discharges and spills from port activities and effluents and contaminants from stormwater outfalls of the City of Cape Town. While there is some contamination of sediments and biota adjacent to contamination sources, there is no evidence of contamination build-up in the bay, which is regularly flushed by wave and circulation processes (Lwandle, 2006a). Some of the marine resources in Table Bay are exploited by commercial and recreational fisheries . These include (Lwandle, 2006a):
• Abalone – There are commercial fishing zones from Cape Point to Mouille Point, Blouberg to Cape Columbine and at Robben Island. Most abalones are found on rocky reefs shallower than 10 m and are closely associated with kelp beds;
• White mussel – White mussels are harvested recreationally for bait and consumption. A large population occurs at Bloubergstrand (Big Bay) and Milnerton Beach;
• Commercial linefisheries – The Table Bay region supports commercial linefisheries for a number of species such as Hottentot, Snoek, Long Fin Tuna, Chub Mackerel and Chokka. The number of boats involved in the fishery is relatively large, with up to 100 boats on the water during snoek 'runs', particularly around Robben Island. Hottentot is most regularly fished in deeper reefs 3.5 – 5.5 km offshore south of Mouille Point.
Port of Cape Town Species associated with artificial surfaces in the port may have different community structures than those found in more natural habitats. Harbours are also typical locations for the introduction of alien species through ships transporting organisms on their hulls or in their ballast waters (Lwandle, 2006a). Large numbers of juvenile rock lobsters can be found on the vertical faces of the outer harbour wall . Other major components of the wall community are encrusting corallines, barnacles, sea urchins, mussels and sponges. The biofouling community appears to be well-developed at the outer harbour areas (Lwandle, 2006a). Further into the harbour , benthic species diversity declines drastically. In addition to a few barnacles, sea squirts and green algae, the alien anemone Metridium senile and alien European shore crab Carcinus maenas have been found. The sites with the lowest diversity and sparsest cover are near the dry dock and the synchro-lift in the Alfred Basin. Benthos inhabiting the sediments within the harbour appears to be limited if not completely absent in the interior of the Victoria and Alfred Basins, attributed to a high level of anoxia within the sediments and pollution in these basins. No benthos sampling results have been reported for the Ben Schoeman Dock or the outer areas of the harbour (Lwandle, 2006a). There appears to be no published information on communities inhabiting the water column in the harbour. It is known that euphausiids occasionally occur in the port, reaching densities sufficiently high to clog the Two Oceans Aquarium seawater intakes. Small shoals of Mullet can be common in
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 64 the outer harbour area, particularly along the seawalls between the entrance to Duncan Dock and the western breakwater. There is also a resident or semi-resident Fur Seal population within the Port (Lwandle, 2006a).
Proposed Dredge Disposal Sites Site 1 (see Figure 5-1) displays a higher benthic biomass and biomass richness and evenness than Site 2. Site 2 has a lower benthic biomass and an increased diversity in benthic macrofaunal community structure, in line with the higher diversity of habitats within Site 2. Both sites display taxon/abundance relationships that do not indicate any pollution effects (Lwandle, 2006a). The macrobenthic fauna abundance on Site 1 is dominated by Annelida, most of which are polychaete worms. Crustaceans and molluscs are also represented. Despite being relatively minor contributors in terms of abundance, molluscs and other fauna dominate the biomass. There appears to be a high degree of homogeneity across the site. Rare taxa appear to be well represented (see Figure 5-4) (Lwandle, 2006a). The macrobenthic fauna abundance on Site 2 is even more clearly dominated by Annelida (polychaete worms) than on Site 1. Molluscs and other taxa also make smaller contributions to the benthic macrofauna community biomass than at Site 1 (see Figure 5-4) (Lwandle, 2006a). The distribution of abundance amongst the taxa is more skewed on Site 2 than on Site 1, in line with the wider range of sedimentary habitats on Site 2. They may be more unstable than in those on Site 1, as indicated by the well developed ripples in the coarser sediments shown on the side-scan.
Block #1: Abundance Block 1: Biomass
Crustacea Mollusca Annelida Other Crustacea Mollusca Annelida Other
Block #2: Abundance Block 2: Biomass
Crustacea Mollusca Annelida Other Crustacea M ollusca Annelida Other
Figure 5-4: Macrobenthos abundance and biomass at dredge disposal sites 1 and 2 23 Source: Lwandle, 2006a
23 Note that “Block 1” and “Block 2” essentially represent the characteristics of macrobenthic fauna at “Site 1” and “Site 2” respectively, but also include some sampling points outside of the actual site in each case (i.e. thus representing a larger area in each case)
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 65 5.2 Socio-Economic and Cultural Environment
5.2.1 Port Infrastructure and Operations The Ben Schoeman Dock is located within the Port of Cape Town, which is situated at the southern shore of Table Bay, to the north-east of Cape Town Central Business District (CBD) and north of Table Mountain. Besides the Ben Schoeman Dock the Port of Cape Town also comprises the Duncan Dock and the Victoria Basin. The Port houses various economic activities, including commercial activities such as cold storage facilities, fishing and import and export. Between 4 000 and 5 000 vessels per annum utilise the port. The areas surrounding the Victoria Basin have been redeveloped to house the world-renowned recreational and commercial facilities which comprise the V&A Waterfront. The basins themselves currently house local fishing fleets and port marine services such as tugs and crane vessels. The Robinson Dry Dock and the Syncrolift ship lift are important ship repair facilities which are also situated here. The Duncan Dock houses the Fresh Produce Terminals as well as the Multi Purpose Terminal, which facilitates the bulk and break-bulk cargoes in the port. The Royal Cape Yacht Club occupies the small craft basin which is also situated in the Duncan Dock. The Sturrock Dry Dock, the Tanker Basin which handles fuel throughput, as well as the Eastern Mole which facilitates other liquid bulk products, are also situated in this dock. The Ben Schoeman Dock, which is the site of the proposed berth deepening, is the dock which facilitates all containerised cargo. The Cape Town Container Terminal is situated here. The berth deepening is being proposed to support the increased demands of this terminal (Shangoni, 2006).
5.2.2 Port of Cape Town within the Socio-Economic Environment of the Western Cape The Port of Cape Town is a landmark feature of the City of Cape Town, lending a maritime dimension which is integral to the city’s cultural landscape. It is a gateway to the city’s tourism industry, standing side-by-side with the world-renowned V&A Waterfront. The Port is a key feature in the regional economy of the Western Cape, and influences the city’s spatial development and employment opportunities. The Port is the site of a number of economic activities. These include:
• Commercial activities such as cold storage facilities and container depots;
• Import and export: the Port’s export function is an important contributor to the Western Cape economy. Through its export of fresh produce - much of which is grown in the region - it is integrally linked to the agricultural sector. In 1997 its exports contributed 16% to the Western Cape’s Gross Regional Product and supported economic activities which employed almost 500 000 people;
• The leasing of terminals to private enterprises;
• The transport of petroleum products, with a throughput of 3 million tonnes per annum;
• Fishing, with the Port representing an important support and control site for the fishing industry; and
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 66 • Tourism and recreation activities, with the berthing of cruise liners and the Two Oceans Aquarium, as well as the close and complex relationship that exists between the Port and the V&A Waterfront. The maritime atmosphere which the Port provides is a key attraction for visitors to the Waterfront and to Cape Town. The Port of Cape Town provides a range of employment opportunities, both from direct employment as well as from related activities such as ship repair and engineering services. The Port property also hosts a number of businesses whose activities are unrelated to the Port. In 1998, it was calculated that approximately 5 300 people relied on the Port (directly) for employment. More than 90% of those employed directly in Port operations come from the impoverished areas of the Cape Flats. The Port is thus a key contributor of income to these poorer communities. In addition to the benefits through employment which the Port provides to the City of Cape Town, a more integrated relationship between the Port and the City could improve road infrastructure planning, as well as capitalising on tourism opportunities and improving public access to the Port; The expansion of Cape Town’s container handling capacity is closely linked to broader Western Cape and National economic and trade conditions. The Western Cape Province represents around 15 % of the National economy, based primarily upon the presence of Metropolitan Cape Town. The city generates around 77 % of the Region’s Gross Domestic Product (GDP) and is the major centre for population, employment and commercial activities. There is an expectation that the Western Cape economy will continue to expand between 4 and 5 % over the medium term. With the primary drivers remaining stable, expansion will be primarily led by consumer demand and capital investment. It is estimated that 75 % of Cape Town’s container throughput is generated or destined for locations within 50km of the port. Of the balance an estimated 15 % is distributed within a hinterland stretching 50-200km form the Port and the balance related to other South African destinations, notably Gauteng.
5.2.3 Tourism and Recreational Activities in Table Bay Robben Island, the world-famous site of Nelson Mandela’s imprisonment, is situated in Table Bay. The Island has been declared a National Monument, as well as receiving World Heritage Status, and receives thousands of local and foreign visitors annually. The tours launch from the Port and as such, Robben Island provides a critical marketing link to the Port. Table Bay is also the site of a number of recreational activities, including fishing, power boating, leisure cruises, surfing and sailing events (Shangoni, 2006). The Victoria and Alfred Waterfront serves as a significant tourist facility, including a number of restaurants, shopping and entertainment facilities as well as the Two Oceans Aquarium.
5.2.4 Marine Archaeology The Table Bay region is the site of significant heritage resource material. This material comprises three categories: pre-historical material under water and on shore, shipwrecks and anchorage debris. However, as a result of extensive blasting and dredging activities that took place in the Port of Cape Town during the 1970’s, there are areas of the port where much of this heritage resource material has either disappeared, or is no longer in situ , thereby losing its contextual archaeological value. The
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 67 areas which were less disturbed during the 1970’s have higher archaeological significance because of the increased likelihood of finding heritage artifacts in these areas (Werz, 2006). Pre-historical material underwater and on shore: On 4 February 1995, one of the most pristine examples of an Acheulean hand axe, dating to the Paleolithic period, was discovered approximately 100 metres offshore opposite Paarden Eiland. This provided evidence of the earliest periods of human presence in the Table Bay region. Human burials of indigenous people along the shores of Blaauwberg, Milnerton and Paarden Eiland dating to 3000 Before Present (BP), as well as more recent burials dating to the early colonial period, also provide archaeological evidence of human presence in the region. Shipwrecks: During the nineteenth and twentieth centuries, the Port of Cape Town developed in response to its importance as a shipping route, with a proportional increase in shipping traffic and the associated shipping incidents which often led to total loss of vessels and their contents. The types of vessels ranged from large merchantmen which plied the trade routes between Europe and Asia, to smaller vessels for fishing, reconnaissance and the transfer of goods and passengers. These shipwrecks represent the richest source of heritage resource material for maritime archaeologists, especially as they are derived from at least 21 different nations. The cause of the wrecks could most often be attributed to natural conditions, with the strong westerly and north-westerly winds trapping the ships in the bay and pushing them into the shallows or onto shore. The majority of the 360 identified wrecks in Table Bay are near the south and south- eastern shores of the bay and, owing to land reclamation since the latter half of the nineteenth century, many of the sites are now covered by the Foreshore and the Cape Town Waterfront. Anchorage debris: The old anchorage grounds, or roadstead, opposite the Castle, have been partly covered by later developments. The remaining roadstead may, however, be the site of anchorage debris, which includes lost anchors and equipment and cargo lost or jettisoned overboard. In addition, owing to the lack of exact demarcation of the roadstead, as well as that ships may have put anchor beyond the anchorage grounds, it is not possible to demarcate an exact area where anchorage debris may be found, but suggests a general area east of 18°24’ longitude and south of 33°50’ latitude (CSIR, 2004).
5.2.5 Visual and Aesthetic Environment The City of Cape Town and the area around the port in particular accommodate a number of different activities and users that influence the sense of place at a micro and macro scale. Areas outside of but adjacent to the Port of Cape Town to the east and south, particularly Paarden Eiland and Beach Road in Woodstock, are industrial in nature. Areas located further to the south and south- west, including Woodstock, Zonnebloem, the Central Business District (CBD) and the V&A Waterfront, are dominated by residential and commercial uses. Relevant areas are indicated on Figure 5-5.
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Figure 5-5: Industrial, residential and commercial areas around Port of Cape Town The Port of Cape Town itself is a working harbour with a long history. The port is now a modern harbour serving Cape Town and its hinterland. It is equipped with an extensive industrial infrastructure designed to accommodate, load and offload vessels with a wide range of sizes and cargoes. The sense of place is one of a working harbour in a visually appealing context, which creates a visual character that is industrial but congruent. The mountains surrounding the city and Table Bay provide a number of viewpoints over the bay, which includes the port. These view points include the tops of Table Mountain (accessible on foot or by cable car), Lion’s Head (accessible on foot) and Signal Hill (accessible by car) (see Figure 5-6).
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Table Mountain
Paarden Lion’s Island Head Signal Cape Town Hill CBD BSD
Port of Cape Town V&A
Waterfront Figure 5-6: Port of Cape Town and surroundings
5.2.6 Traffic and Transport The transport infrastructure within the vicinity of the Port of Cape Town comprises both a road and rail network. The roads primarily serving the port are Duncan Road (not a public road), Marine Drive; the N1 Freeway and the N2:
• The N1 links Central Cape Town and the Port to the rest of the metropolitan area and the hinterland. In the vicinity of the Port, the N1 carries very high commuter peak period flows and operates under congested conditions (due to commuter traffic) in the peak direction of flow for approximately two hours during each of the weekday commuter peak periods;
• Marine Drive links Central Cape Town and the Port to Milnerton and Table View as well as the industrial areas of Paarden Eiland, Marconi Beam and Montague Gardens. Traffic conditions on Marine drive during a typical working day can be summarised as follows:
− AM peak period (06h30 – 09h00): high levels of congestion along Marine Drive in the southbound direction; lower levels of congestion in the northbound direction, but significant delays accessing Marine Drive via the N1 Freeway.
− Inter-peak period (09h00 – 16h00): lower levels of congestion along Marine Drive in north- and southbound directions, although due to the occurrence of “peak extension” and general traffic growth, these levels are steadily being raised.
− PM peak period (16h00 – 18h00): relatively low levels of congestion along Marine Drive in the southbound direction; high levels of congestion in the northbound direction.
• Duncan Road lies within the port’s functional area. Peak hour flows on Duncan Road also reflect commuter patterns related to the CBD as this route is used as a “rat-run” for traffic wishing to bypass congestion at the Marine Drive interchange with the N1. It should be noted that these flows are at present considerably lower than in 2003, when a previous survey was done, due to the stricter controls at the access points to the Port.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 70 The following freight rail operations are relevant to this investigation:
• Along the Harbour/ Monte Vista rail line, which runs adjacent to Marine Drive and then adjacent to Duncan Road within the port functional area, and terminates at the Unity Yard. Currently, there are approximately 18 train movements along this line during the day (between 06h00 and 18h00), and 12 at night. This translates into average train headways (time intervals between successive trains) of 40 minutes during the day, and 60 minutes at night; and
• Between the Paarden Eiland and Unity Yard along the rail culvert underneath the N1 Freeway. Currently there are approximately 12 train movements along this line during the day, and 8 at night. This translates into average train headways of 60 minutes during the day, and 90 minutes at night.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 71 6 Public Consultation Process
6.1 Introduction Public consultation is a key component of the EIA process. It usually occurs in three phases:
• Phase 1: Identification of and consultation with key stakeholders or Interested and Affected Parties (IAPs), which was initiated upon commencement of the Scoping Study to identify potential issues and impacts to consider in the Scoping Report.
• Phase 2: Public consultation with key IAPs to solicit comment on the Draft Scoping Report to refine the specialist Terms of Reference and ensure that the relevant impacts are assessed.
• Phase 3: Public consultation with key IAPs to solicit comment on the draft Environmental Impact Report (EIR) prior to finalisation and submission to DEAT. The objectives of the public consultation process are outlined below, followed by a summary of the approach and issues raised to date.
6.2 Objectives of the Public Consultation Process The objectives of the public consultation process are to:
• Identify and inform key IAPs, including relevant authorities, about the proposed activities to be undertaken at the Ben Schoeman Dock;
• Ensure timely dissemination of information that is understandable and accessible to all IAPs;
• Provide IAPs with the opportunity to identify key issues and concerns associated with the project;
• Identify potential impacts which need to be assessed in the EIA;
• Gauge the level of acceptance of the proposed project; and
• Allow for IAP comments on the draft reports produced as a result of the EIA process (Scoping Report and EIR).
6.3 Public Consultation during the Scoping Phase The Scoping Phase of the study, and hence that phase’s Public Consultation Process, were undertaken by Shangoni and resulted in the identification of a number of issues and concerns. The activities undertaken as part of the Public Consultation Process during the Scoping Phase are described in the Final Scoping Report for the project (Shangoni, 2006). In response to comments received by IAPs on the Draft Scoping Report (DSR) released in May 2005, Shangoni revised the report significantly and re-released it for public comment in September 2005. A summary of the Scoping Phase public consultation activities as laid out in the Final Scoping Report is provided in Table 6-1 below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 72 Table 6-1: Summary of consultation activities during the Scoping Phase Activity Responsible Date Submission of Plan of Study for Scoping to DEA&DP and Shangoni 11 April 2005 DEAT Acceptance of the Plan of Study for Scoping by DEA&DP DEA&DP Date not available Phase 1 Consultation – Initiation Phase Advertisement of the commencement of the study and call for Shangoni Date not available IAP registration in local and regional newspapers Identification of key stakeholders Shangoni April – May 2005 Circulation of Background Information Document and Shangoni May 2005 pamphlets to identified IAPs Phase 2 Consultation – Scoping Phase Notification of registered IAPs of the public review period of the Shangoni 30 May 2005 Draft Scoping Report (DSR) in the Cape Times Comment period following the release of the DSR Shangoni 27 May 2005 – 30 June 2005 Stakeholder scoping meeting Shangoni 27 May 2005 Public meeting Shangoni 9 June 2005 Notification of registered IAPs of the public review period of the Shangoni 21 - 22 September 2005 Revised DSR in the Cape Times Shangoni 21 September 2005 - Comment period following the release of the Revised DSR 21 October 2005 Submission of Final Scoping Report to DEAT and DEA&DP Shangoni March 2006 Acceptance of Final Scoping Report by DEAT DEAT 9 June 2006 Source: Shangoni (2006)
6.3.1 Issues raised during Scoping Process A detailed record of issues and comments from IAPs during the scoping process can be found in Annex B of the Final Scoping Report (Shangoni, 2006). In the Final Scoping Report (FSR), issues were classified as:
• Issues that could be adequately addressed or resolved in the Scoping phase (for which responses were provided in Section 6.2 of the FSR); and
• Issues that require further investigation, in particular through the involvement of specialists as presented in the Plan of Study for EIA (Section 6.3 of FSR).
• A summary of the issues requiring further specialist investigation during the EIA is presented in Table 6-2. Based on the decision to eliminate the land-based and nearshore (~15m) dredge disposal option and the exclusion of the Container Terminal Expansion project from this EIA, some of these issues are no longer applicable, and have been indicated as such in the table.
• These issues informed the Terms of Reference for the Specialist Studies undertaken as part of this EIA, and the relevant specialist study through which each issue has been addressed has been indicated.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 73 Table 6-2: Issues identified in the Scoping phase requiring further investigation Key Issues Reference 1) Dredging and Disposal of Dredge Spoil Identification of dredging method and transport of dredged material Integrated Marine Report from the BSD to the marine disposal site. (Appendix C) Duration of dredging operations for proposed activities; seasonal and Integrated Marine Report daily dredging schedule. (Appendix C) Identification and assessment of impacts for alternative marine Integrated Marine Report dredge disposal locations, ranging from deepwater sites (>40m water (Appendix C) depth) through to disposal into the surfzone or beach area. Options to be assessed in the EIA have been narrowed to two deepwater sites at ~40m and ~65m depths. Uncertainty regarding the frequency with which turbidity thresholds Integrated Marine Report (for marine ecology) are exceeded at disposal site(s) in Table Bay (Appendix C) and implications for the construction programme (i.e. would construction have to stop for these periods). Implications of dredge disposal to a deep water anoxic environment. Integrated Marine Report (Appendix C) Concerns regarding the disposal of the non London Convention (LC)- Characterisation of the material to compliant portion of the spoil material to a suitable land-based waste be dredge has indicated that no facility and the associated transport and processing requirements non-LC compliant dredge sediment (e.g.. dewatering of the spoil etc). Identification of a suitable will be dredged, and land-based hazardous waste facility with available capacity. disposal is thus not required. 2) Shoreline Dynamics Potential effects of changes in wave, current and sediment transport Integrated Marine Report regimes as a result of disposal of dredge spoil from the deepening of (Appendix C) BSD on shoreline evolution within Table Bay. 3) Sediment Toxicology and Marine Ecology Impacts associated with dredging and blasting during construction on Integrated Marine Report the ecological environment in BSD. Investigate the implications of the (Appendix C) chemical characteristics of the dredge spoil for ecology. Relocation of marine mammals (e.g. seals) from BSD during Integrated Marine Report construction activities (in particular, blasting) and the identification of (Appendix C) suitable facilities and potential partners (e.g. Cape Nature) for such purposes, should relocation be required. Need to confirm requirements with Cape Nature 24 . During construction, ecological implications of dredge spoil at various Integrated Marine Report locations in the marine environment in terms of smothering of marine (Appendix C) organisms (e.g. filter-feeders) and turbidity. During construction, turbidity thresholds that should be applied to Integrated Marine Report avoid a significant impact on marine organisms. (Appendix C) Impacts of noise, vibration and shock on the marine ecology within Integrated Marine Report the BSD basin. (Appendix C) 4) Noise, Vibration and Shock Identification of the most significant sources of noise during the Noise Shock and Vibration Study construction and operation of the proposed project (including (Appendix D) frequency and nature of noise). Identification of main receptors for acoustic impacts (e.g. surrounding Noise Shock and Vibration Study communities and businesses). (Appendix D) Analysis of noise impacts on the ambient (current) noise environment. Noise Shock and Vibration Study (Appendix D) Impacts of vibration and shock on existing port infrastructure. Noise Shock and Vibration Study (Appendix D)
24 Note that Cape Nature will need to be contacted in this regard in determining exact procedures to be followed, for inclusion in the EMP.
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5) Traffic and Transportation Impacts of road-based transport associated with construction Traffic Impact Assessment activities on traffic movements in port and nearby road infrastructure. (Appendix E) Identification of additional traffic volumes, routes and vehicle types Traffic Impact Assessment generated during the construction and operation of the proposed (Appendix E) activities. Cumulative impacts of road-based transport associated with Traffic Impact Assessment simultaneous constructions activities from the BSD and Container (Appendix E) Terminal Expansion projects. Risks and transport impacts associated with transport of Characterisation of the material to contaminated dredge spoil by road to a suitable land-based be dredge has indicated that no hazardous waste facility. non-LC compliant dredge sediment will be dredged, and land-based disposal is thus not required. 6) Visual Aspects Visual impacts of surface turbidity plumes (especially during calm Visual Impact Assessment periods). (Appendix F) 7) Maritime Archaeology Potential impacts on heritage (i.e. archaeological and historical Maritime Archaeology Assessment features associated with the BSD project). Need to consult with the (Appendix G) South African Heritage Resources Agency (SAHRA). 8) Risk Profile of Port Impacts of proposed activities and use of larger vessels on the risk Although this has to some extent profile of the Port with regards to pollution events. been addressed in Appendix C, it is essentially outside the scope of the EIA
6.4 Public Participation during the EIA Phase The EIA Phase of the study, and the associated Public Consultation Process, are being undertaken by SRK. The main activities that have been and are to be undertaken as part of the Public Consultation Process during the EIA Phase are listed in Table 6-3. Table 6-3: Summary of consultation activities during the EIA Phase Activity Responsible Date Phase 3 Consultation – EIA Phase Submission of Plan of Study for EIA to DEA&DP CSIR April 2006 Submission of revised Plan of Study for EIA to DEAT SRK 5 September 2006 Acceptance of revised Plan of Study for Scoping by DEAT DEAT 31 October 2006 Notification of registered IAPs of change in consultant and SRK 20 November 2006 project scope Notification of registered IAPs of the public review period of the SRK 9 February 2007 Draft Environmental Impact Report (EIR) SRK 12 February 2007 - Comment period following the release of the Draft EIR 13 March 2007 Focus Group meetings (if and when required) SRK 19 February – 2 March 2007 Open Day SRK 27 February 2007 Submission of Final EIR to DEAT and DEA&DP SRK 29 March 2007 (forecast)
6.4.1 Identification of IAPs SRK has amended the database of IAPs that was compiled by Shangoni during the Scoping Phase to include additional IAPs that have been identified since. To date, approximately 140 stakeholders are included in SRK’s database for this project. A list of IAPs involved in the process is provided in Appendix B.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 75 All IAPs on the database were informed by letter on 20 November 2006 of the change in consultant and scope of the project.
6.4.2 Discussions with Key Stakeholders During the EIA phase, SRK Consulting and CSIR (responsible for the integrated marine study) held discussions with the following key stakeholders, to ensure that their information requirements would be met:
• DEAT Marine and Coastal Management (regarding information requirements for the permit application, the suitability of the proposed dredge disposal sites, and characterisation of these sites and the sediments to be disposed of);
• Two Oceans Aquarium (regarding water quality requirements, due to the location of their seawater intake within the harbour); and
• South African Maritime Safety Authority (regarding the potential risk to existing shipping activities)
6.4.3 Notification of Draft EIR Release for Comment The release of the Draft Environmental Impact Report (EIR) for public review as well as the date for the associated Public Open Day on 27 February 2007 will be communicated to all registered IAPs by post, email or fax on 9 February 2007.
6.4.4 Release of Draft EIR for comment The Executive Summary of the Draft EIR will be circulated to all stakeholders on 9 February 2007. Full hardcopies of the report will be placed at the following venues:
• Cape Town Library
• Milnerton Library; and
• SRK Office, Rondebosch, Cape Town. The report can also be accessed as an electronic copy on Transnet’s website www.transnet.co.za/TransnetProjects.aspx (on the Home page select “Doing business with Transnet” followed by “Transnet Projects”). Stakeholders will be provided with a 30-day comment period which will commence on Monday 12 February 2007 and end on Tuesday 13 March 2007. Comments received will be incorporated into the Final EIR.
6.4.5 Public Open Day A Public Open Day will be held on 27 February 2007 from 15h00 – 19h00. All registered IAPs will be invited to attend and the public open day will be advertised in the press. The purpose of the Open Day will be to allow IAPs access to the results of the EIA Phase and to provide an opportunity for questions and comments.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 76 7 Assessment of Environmental Impacts
7.1 Introduction During the Scoping process, potential environmental impacts associated with the proposed deepening of the Ben Schoeman basin, and associated upgrade to Berth 601, 602, 603 and 604 have been identified. The specialist studies undertaken to address these issues listed in chapter 6 of this report included:
• Integrated Marine Assessment including:
• Shoreline Stability;
• Sediment movement associated with dredging and dredge disposal;
• Marine Ecology and Toxicology;
• Noise, Shock and Vibration Assessment;
• Traffic Impact Assessment;
• Visual Impact Assessment; and
• Marine Archaeology Assessment. Proposed Terms of Reference for each of the specialist studies, based on the project description provided in Chapter 3 were included in the Revised Plan of Study for EIA, as approved by DEAT. Each of the specialist studies, presented in this chapter, assessed impacts associated with the upgrade to berths, cranes and dredging activities at the Ben Schoeman Dock, and where appropriate, the impacts of disposal of dredge spoil at each of the two potential dredge disposal sites identified. All specialists were required to rate the significance of anticipated impacts and to recommend practical mitigation measures, where appropriate. The specialist studies have been collated in a separate Supplementary Volume of Specialist Reports, which accompanies this Draft EIR.
7.2 Impact Rating Methodology
7.2.1 Impact Rating Procedure Each specialist provided a description of the baseline conditions at the site as well as the description and assessment of the potential impacts on the environment. The assessment of impacts was based on the professional judgment of the specialists, fieldwork and desk-top analysis. The significance of potential impacts that may result from the proposed project were determined in order to assist decision-making by DEAT. The significance of an impact is defined as a combination of the consequence of the impact occurring and the probability that the impact will occur. The criteria used to determine the consequence of an impact are presented in Table 7-1 below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 77 Table 7-1: Criteria used to determine the consequence of the impact
Rating Definition of Rating Score A. Extent – the area in which the impact will be experienced None 0 Local Confined to project or study area or part thereof (e.g. site) 1 Regional The region, which may be defined in various ways, e.g. cadastral, catchment, 2 topographic (Inter)national Nationally or beyond 3 B. Intensity – the magnitude or size of the impact None 0 Low Wider (off site) natural and/or social functions and processes are negligibly altered 1 Medium Wider (off site) natural and/or social functions and processes continue albeit in a 2 modified way High Wider (off site) natural and/or social functions or processes are severely altered 3 C. Duration – the time frame for which the impact will be experienced None 0 Short-term Up to 2 years 1 Medium-term 2 to 15 years 2 Long-term More than 15 years 3 The combined score of these three criteria corresponds to a Consequence Rating , as set out in Table 7-2: Table 7-2: Method used to determine the consequence score
Combined Score (A+B+C) 0 – 2 3 – 4 5 6 7 8 – 9 Consequence Rating Not significant Very low Low Medium High Very high
Once the consequence was derived, the probability of the impact occurring was considered, using the probability classifications presented in Table 7-3 below. Table 7-3: Probability classification
Probability of impact – the likelihood of the impact occurring Improbable < 40% chance of occurring Possible 40% - 70% chance of occurring Probable > 70% - 90% chance of occurring Definite > 90% chance of occurring The overall s ignificance of impacts was determined by considering consequence and probability using the rating system prescribed in Table 7-4.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 78 Table 7-4: Impact significance ratings
Significance Rating Consequence Probability Insignificant Very Low & Improbable Very Low & Possible Very Low Very Low & Probable Very Low & Definite Low & Improbable Low & Possible Low Low & Probable Low & Definite Medium & Improbable Medium & Possible Medium Medium & Probable Medium & Definite High & Improbable High & Possible High High & Probable High & Definite Very High & Improbable Very High & Possible Very High Very High & Probable Very High & Definite Finally the impacts were also considered in terms of their status (positive or negative impact) and the confidence in the ascribed impact significance rating. The prescribed system for considering impacts status and confidence (in assessment) is laid out in Table 7-5 below. Table 7-5: Impact status and confidence classification
Status of impact Indication whether the impact is adverse + ve (positive – a ‘benefit’) (negative) or beneficial (positive). – ve (negative – a ‘cost’) Neutral Confidence of assessment The degree of confidence in predictions Low based on available information, SRK’s Medium judgment and/or specialist knowledge. High The impact significance rating should be considered by DEAT in their decision-making process based on the implications of ratings ascribed below:
• Insignificant : the potential impact is negligible and will not have an influence on the decision regarding the proposed activity/development.
• Very Low : the potential impact should not have any meaningful influence on the decision regarding the proposed activity/development.
• Low : the potential impact may not have any meaningful influence on the decision regarding the proposed activity/development.
• Medium : the potential impact should influence the decision regarding the proposed activity/development.
• High : the potential impact will affect the decision regarding the proposed activity/development.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 79 • Very High : The proposed activity should only be approved under special circumstances. Specialists were required to recommend mitigation measures, and rate impacts both without and with implementation of the mitigation measures recommended. Mitigation measures are either:
• Essential : must be implemented and are non negotiable; or
• Optional: should be considered, and sound reasons provided by Transnet if not implemented. As the implementation of “optional” mitigation measures cannot be assumed, the rating of impacts with mitigation assumes only the implementation of essential mitigation measures.
7.2.2 Cumulative and Indirect Impacts Where appropriate, specialists were required to assess cumulative and indirect impacts. In most cases these assessments were qualitative and descriptive.
7.2.3 Integration of Studies into the EIA The completed specialist studies and their findings have been integrated into the Draft EIR. The key findings of each specialist were evaluated in relation to each other to provide an overall and integrated assessment of the project impacts. SRK has considered the suite of potential impacts in a holistic manner and in certain instances, based on independent professional judgment and this integrated approach, has altered impact significance ratings. Where this has been done it has been indicated in the relevant section of the report.
7.3 Potential Marine Impacts
7.3.1 Marine Impact Study Introduction and Terms of Reference This section of the report has been based on the Integrated Marine Study undertaken by CSIR and attached as Appendix C1. This Integrated Marine Study is based on three detailed specialist studies including:
• Specialist study on Sediment Toxicology and Marine Ecology, undertaken by Lwandle Technologies (Pty) Ltd (Appendix C2);
• Specialist study on Shoreline Dynamics in Table Bay, undertaken by the CSIR (Appendix C3); and
• Specialist study on Dredging and Disposal of Dredge Spoil, undertaken by the CSIR (Appendix C4). Each of these individual specialist studies have undergone external specialist review, and relevant comments by reviewers, as well as responses to the comments, as provided by CSIR included in Appendix C5. Where appropriate, responses to comments by reviewers have been addressed in the final specialist reports used for the purposes of this EIA.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 80 Integrated Marine Study: The approach to the Integrated Marine Study was as follows:
• A preliminary characterisation was undertaken of the physical and biogeochemical properties of the material to be dredged from the Ben Schoeman Dock. Based on this characterisation, available literature and other information such as bathymetric charts, a screening of potential dredge disposal sites was undertaken and two sites identified (as required by the project brief). Field surveys were then planned to characterise the physical, biogeochemical and ecological characteristics and significance of these proposed dredge disposal sites;
• The field survey was undertaken over a period of three days (31 August 2006 to 2 September 2006) and included a bathymetric survey, a side-scan sonar survey and sampling of the sediments at the seabed. The sampling was undertaken based on the geophysical characteristics of the seabed and habitats inferred from the side-scan sonar survey;
• Sediment samples from the disposal sites were characterised in terms of their physical properties (grain size analysis), biogeochemical properties (trace metals) and benthos. Simultaneously, the existing geotechnical cores from the Ben Schoeman Dock were sub-sampled and analysed to ascertain the trace metal loads in the deeper sediments to be dredged from the Ben Schoeman Dock. (The characteristics of the surface sediments were already known from previous CSIR survey within the Port of Cape Town.);
• An assessment of potential impacts in the marine environment was undertaken based on:
− the quantities and characterisation of the sediments to be dredged;
− the characterisation of the proposed dredge disposal sites,
− consideration of potential environmental effects of dredging and dredge disposal activities, and
− the sensitive ecosystems and existing beneficial uses of regions likely to suffer impacts, A simulation modelling approach was used to predict the behaviour and distributions of suspended sediments, associated contaminants and discharged sediments associated with the proposed dredging of the Ben Schoeman Dock basin. Modelling considered:
• each of the three dredging options;
• disposal at each of the two potential dredge disposal sites; and
• disposal of dredge spoil under summer and under winter conditions. The approach used in the assessment of marine impacts has been to select the apparent worst case scenarios and to evaluate the associated impacts. The approach is thus essentially conservative. Included is this conservative approach is the modelling and assessment of marine impacts with the assumption that volumes of spoil dredged from the harbour are 10% 25 larger than stated in the project description (Table 3-2). This is a safety margin to ensure a robust EIA description should
25 This is a factor of safety as the exact volume of material to be removed cannot be accurately estimated, and does not relate to the “bulking” of sediments once brought to the water surface.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 81 there be over dredging. The specific terms of reference for each of the individual marine-related specialist studies were as follows: Sediment Toxicology and Marine Ecology:
• Assess the dredge sediment properties in terms of particle size distributions, contaminant concentrations, and toxic condition. The data for this will be drawn from the CSIR sediment property surveys and previous investigations commissioned by the NPA. These will be supplemented by analyses to confirm the vertical distribution of chemical properties such as metals in the sediments to be dredged. These supplemental analyses will require access to and sub-samples (mid-depth and full depth of proposed dredging) of the drilled cores in the Ben Schoeman Dock. The analyses will comprise assessment of total metals in the samples as well as grain size analyses;
• Identify areas that may be at risk from the proposed activities. For dredge spoil disposal this will require access to the results of the dredge spoil simulation modelling to be conducted as part of the EIA by CSIR;
• Identify the biological communities that may be at risk from the proposed operations. This will be based on information sourced during the container terminal expansion EIA and the recent SEA conducted for the port as well as the proposed fieldwork;
• Qualify the risks that the proposed operations may pose in terms of accepted water and sediment quality guidelines. This will be based on the recently (2006) compiled water quality guidelines for the BCLME programme. These Guidelines are based on up-to-date international best practice, Australian and New Zealand practice, DWAF water quality guidelines for RSA coastal waters and work published in the scientific literature;
• If water/sediment quality guidelines are exceeded, quantify the risks in terms of the proportions of biological populations under threat and qualify these in terms of ecological consequences;
• Where required, identify the need for mitigation and suggest methods to achieve this;
• Devise a practical monitoring programme that will, firstly, allow real time control of project activities to reduce environmental risks and, secondly, facilitate a qualitative determination of actual versus predicted project impacts;
• Conform to any relevant guidelines for specialist studies issued by the DEA&DP. Shoreline Dynamics:
• Confirm whether disposal of dredge spoil at depths of 40 - 70 m or 70 - 100 m have any significant impact on shoreline stability (erosion/accretion) in Table Bay using a review of recent literature;
• If the study indicates a likely impact on shoreline stability, undertake the contingency study as outlined in the contract documentation 26 ; and
26 The outcome of the initial literature survey and screening study indicated that the contingency study as proposed was not necessary, provided that specific requirements in terms of the nature of the dredge disposal could be fulfilled by the dredging contractor.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 82 • Conform to any relevant guidelines for specialist studies issued by the DEA&DP. Dredging and Disposal of Dredge Spoil:
• Identify likely dredging methods and options of transporting dredged material from the BSD to the marine disposal site;
• Estimate the likely duration of dredging operations as well as seasonal and daily dredging schedules;
• Locate and characterise two sites at between 40m to 70m and 70m to 100m of depth, respectively, that would be suitable for the disposal of dredge spoil using preliminary side-scan and bathymetric survey techniques as well as sampling of sediment;27
• Produce a model of the disposal of dredge material at the following disposal sites:
• Deep water (between 40m and 70m) dredge disposal; and
• Deep water (between 70m and 100m) dredge disposal;
• If required, assess concerns regarding the disposal of the non LC-compliant portion of the spoil material to a suitable land-based waste facility and the associated transport and processing requirements (e.g. dewatering of the spoil etc); and
• Conform to any relevant guidelines for specialist studies issued by the DEA&DP. In the case of the marine study, much of the work undertaken was aimed at identifying suitable dredge methodologies, dredge disposal sites, and obtaining baseline information, based on which an assessment of the marine (and other) impacts could be undertaken.
7.3.2 Marine Baseline Information A detailed description of the marine environment has been provided in the integrated marine report (and associated specialist reports) as well as in Chapter 5 of this EIR. Baseline information relevant to the impacts on the marine environment has been summarised in this section for ease of reference. Important components of the marine ecosystem in Table Bay are the habitats within the bay, the benthos, the Table Bay pelagic communities, the Table Bay harbour communities, seabirds and marine mammals. Important resources and recreational fisheries in Table Bay include:
• Three important commercial abalone zones;
• White mussel ( D. Serra ) that are harvested recreationally for bait and human consumption;
• Commercial line fisheries for Hottentot, Snoek and other species including Long Fin Tuna, Chub Mackerel and Chokka.
27 Note that although the original requirement was to identify one of the sites at 70 to 100m depth, the suitable site identified during the side scan sonar ranges from 65 to 75m depth. This is not considered problematic in any way, and the identification of this site has been discussed in detail with MCM.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 83 In terms of biogeography and unique biodiversity resources, the rocky shore and sandy beach communities (with the exception of dense white mussel beds at Bloubergstrand), the benthic communities and the pelagic fish and marine mammals occurring in Table Bay are typical of the West Coast and not unique to Table Bay. Table Bay therefore cannot be classified as a locally, regionally or internationally important biodiversity resource. The only strong exception to the above statement are the seabirds of the area (especially the African Penguin and the Bank Cormorant whose population size, endemism and conservation classification make these seabirds significant biodiversity resources). Existing beneficial uses in Table Bay include:
• Marine Protected and Conservation Areas (i.e. the Table Bay Rock Lobster Sanctuary, the Table Mountain National Park Marine Protected Area and Robben Island which is a provincial nature reserve with no formal Marine Protected Area, however the sea area within a 1 nautical mile radius of Robben Island can be considered to be environmentally sensitive because of its conservation importance to African Penguins and Bank Cormorants;
• Marine outfalls (Green Point pipeline and Chevron/Caltex pipeline);
• Used and disused sea cables with landfalls at Milnerton and Melkbosstrand and from Granger Bay and Murrays Harbour and the Port of Cape Town;
• Vessel navigation and anchorages;
• Recreational activities (surfing, sailing, kite-surfing, swimming, fishing, etc).
• Tourism (e.g. Victoria and Alfred waterfront)
• The Two Oceans Aquarium that is located in the Victoria and Alfred Basin. Biological species diversity and numbers in the harbour are generally low, due to the disturbed nature of the harbour environment. Benthos inhabiting the sediments appear to be limited, if not completely absent due to the existing high pollutant levels in the basin, associated with current activities and stormwater inlets. Dredge disposal Site 1 has a higher benthic biomass and biomass richness than Site 2. Although Site 2 has a lower biomass, it has a higher diversity in benthic macrofauna, due to the higher diversity of habitats represented on this site. Dredge disposal Site 1 is situated approximately 13km offshore of the nearest beach in Table Bay. The nearest beach to the south is Clifton, situated approximately 6km to the south-east of this site. Dredge disposal Site 2 is situated approximately 9km away from the nearest sandy beach in Table Bay. Clifton beach is once again the closest sandy beach to the south, situated about 5km from this site. The beaches that could be affected by a mound of sediment disposed offshore are those which lie in the path of the waves that may conceivably be disturbed by the mound. Figure 7-1 below indicates the typical distribution of wave heights and directions offshore of Table Bay. This indicates that waves from disposal Site 2 move towards to the shoreline in Table Bay ~9km away. Although Camps Bay and Clifton beaches are about 5km away, they are positioned such that they are not on the path of the waves moving from the disposal sites under most conditions. The exception would be
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 84 rare northerly wind-generated waves, although these waves generally have short periods and therefore would be unaffected by small bathymetry changes at depths of about 40m and more.
Figure 7-1: Typical distribution of wave heights and directions in Table Bay
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7.3.3 Marine Impact Assessment Impacts assessed in this section of the report have been broadly divided as follows:
• Impacts on the harbour environment, largely related with dredging activities;
• Impacts on dredge spoil disposal sites, and surrounding areas, largely related to the disposal of dredge spoil; and
• Impacts on existing activities in Table Bay. Potential Impacts on the Harbour The following potential impacts associated with the dredging operation in the harbour were rated as being insignificant and thus not requiring mitigation. They have thus not been discussed in further detail in this report 28 :
• Remobilisation of contaminants in dredged sediments disrupting ecological processes and/or compromising biological organisms;
• Reductions in dissolved oxygen concentrations due to introduction of organic matter previously held in the sediments to the water column affecting biogeochemical processes;
• Release of nutrients previously held in pore waters in the sediments to the water column promoting eutrophication;
• Altered seawater quality through, e.g., remobilised contaminants in the dredged sediment affecting other beneficial uses of the harbour environment;
• The effects of noise from the dredging activities on biological organisms in the harbour;
• The effects of dredging activities on endangered seabirds; and
• Mortality to harbour biota from shock waves generated by small parcel blasting to remove rock. Potential impacts on the harbour environment associated with the dredging operation which have been assessed further in this report include:
• Removal/destruction of biological communities in the dredge target areas;
• Effects of turbid plumes generated by dredging on organisms inhabiting harbour sediments and structures;
• Settlement of material suspended during dredging and alteration of sediment characteristics and associated biological communities;
• Importation of alien species by dredgers and associated ecological effects; and
• Effects of turbidity on endangered coastal seabirds (specifically the African Penguin.
28 Details of the nature and assessment of these impacts are provided in the integrated marine report, and supporting specialist studies.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 86 Potential Impacts on Dredge Disposal Sites The following potential ecological impacts associated with the disposal of the dredge spoil to the designated dredge disposal site were rated as being insignificant and have not been assessed further in this report:
• Potential erosion of the shoreline as a result of dumping of the dredge material.
• Toxic effects of trace metal contaminated dredge spoil on benthos at the dredge spoil dump site and its immediately adjacent area and disruption to ecological processes;
• Effects of turbidity from dredge spoil on habitats adjacent in dump area(s);
• Reductions in water column oxygen concentration in spoil dump area(s) and effects on biological communities; and
• Inundation of intertidal shores in the adjacent marine protected areas. Potential impacts on the dredge disposal sites, and surrounding areas, as a result of the disposal of dredge soil , which have been assessed further in this report include:
• Deposition of discharge sediment and effects on benthic macrofauna;
• Alteration of benthic biological communities through toxins associated with dredge spoil;
• Effects of turbidity generated by dredge spoil disposal on habitats adjacent to the dredge spoil disposal sites;
• Effects on water quality in the Table Mountain National Park MPA (and other MPA’s) and resulting effects on biota as a result of sediment plumes; and
• Introduction of alien species to dredge disposal sites. Potential Impacts on existing activities in Table Bay Two possible impacts of dredging activities and the disposal of dredge material on other existing activities in Table Bay, as assessed in this report include:
• Deposition of sediments in existing dredge areas and/or navigation channels; and
• Interference with existing shipping. Although a potential impact on the Two Oceans Aquarium has been identified due to the seawater intake being positioned in the Victoria and Alfred basin, the Two Oceans Aquarium has established emergency procedures to cope with unsuitable quality intake water. These include running the aquarium system in recirculation mode and/or obtaining seawater from an alternative location such as Granger Bay and using road tankers to transport the water to the aquarium. Therefore, although unlikely to be required, the Two Oceans Aquarium does have procedures in place that would protect it from compromised water quality in the region of its seawater intakes. This potential impact is thus considered to be of low significance and has not been assessed further in this report. Potential marine impacts are described and assessed in more detail in the following sub-sections (both without and with the implementation of the mitigation measures listed in Section 7.3.5)
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 87 7.3.3.1 Impacts on harbour environment Although various dredge scenarios are being considered, the impacts of dredging on the harbour environment are expected to be similar in each case, and where they may differ, the worst case scenario has been assessed for each potential impact.
Impact 1: Removal of biological communities in the dredge target areas During the proposed dredging, approximately 1.23 million m3 of material (which includes hard and soft rock) will be dredged from the port. This material will have marine biota associated with them which will be removed along with the dredge spoil. There is a marked gradient within the port in biofouling organisms on harbour structures, biomass declining rapidly with distance from the harbour entrance. There are no reported surveys on spatial distributions of benthos in the sediments but spot sampling in Duncan Dock, Victoria Basin and Alfred Dock showed a complete absence of fauna (CMS 1995a). This was attributed to anoxic sediments and hydrocarbon pollution. Such a severe situation is not expected for Ben Schoeman Dock Basin sediments, but it is likely that the soft sediment benthos is impoverished. As a result of dredging operations sediments and their associated organisms will be physically removed from the seabed along the path of the dredger during dredging. An area of approximately 1.1 km 2 within the harbour will be affected. The majority of the benthic organisms are likely to die or be removed from the dredge area, although the overall numbers of organisms affected is expected to be low. Due to the local extent of the impact (limited to the harbour area), and the fact that it will occur in what can essentially be considered an artificial habitat, the significance of this impact is considered to be very low, and no mitigation measures are considered necessary or feasible. An assessment of this impact “with mitigation” has thus not been provided below. Table 7-6: Significance of the potential removal of biological communities in the dredge target areas
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Medium Short-term Very low Definite VERY LOW -ve High mitigation 1 2 1 4 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential removal of biological communities in the dredge areas is therefore rated as very low .
Impact 2: Effects of turbid (sediment) plumes generated by dredging on organisms inhabiting harbour sediments and structures Dredging activities characteristically generate turbid plumes of suspended sediment. High suspended solid concentrations can exert negative effects on organisms through light attenuation (phytoplankton and algae), interference with filter feeding (zooplankton, mussels, oysters, barnacles), damage to gills and respiratory processes (mussels, oysters, abalone, fish), reduction of visibility reducing foraging success (cormorants, penguins, predatory fish) but also assisting predator avoidance in fish (Clark 1997a), etc .
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 88 The South African Water Quality Guidelines for the Natural Environment (DWAF, 2005) provide an upper limit for dissolved trace metals as well as a guideline for suspended sediments in the water column. The relevant guidelines are summarised in Table 7-7 below. Table 7-7: South African Water Quality Guidelines for the water column Constituent Upper Limit The following target values apply to marine waters outside of a specific sacrificial zone: Should not be more than 35 Hazen units above ambient concentrations (colour) Colour/turbidity/clarity Should not reduce the depth of the euphotic zone by more than 10 % of ambient levels measured at a suitable control site (turbidity) Should not be increased by more than 10 % of ambient concentrations. Suspended solids This is largely based on aesthetic impacts. Dissolved oxygen should not fall below 5 mg/l (99 % of the time) and Dissolved oxygen below 6 mg/l (95 % of the time) Ammonium, Nitrate, Waters should not contain concentrations of dissolved nutrients that Nitrite, Phosphate, are capable of causing excessive or nuisance growth of algae or other Silicate aquatic plants or reducing dissolved oxygen concentrations below the target range indicated for Dissolved oxygen (see above) + Ammonia 20 µg N per litre (as NH 3) or 600 µg N per litre (as NH 3 plus NH 4 ) Arsenic (As) 12 µg/l Cadmium (Cd) 4 µg/l Chromium (Cr) 8 µg/l Copper (Cu) 5 µg/l Lead (Pb) 12 µg/l Mercury (Hg) 0.3 µg/l Nickel (Ni) 25 µg/l Zinc (Zn) 25 µg/l Source: CSIR (2006b) Due to the fact that the harbour is an environment which is already disturbed, and would not have water quality found under natural conditions the following water quality guidelines and suspended sediment limits that were developed for already disturbed ecosystems, are considered applicable:
• Australian and New Zealand Environment Conservation Council (ANZECC) water quality guidelines (2000) for a moderately to highly disturbed or polluted system (aiming to protect 80% of species with a 95% certainty). These guidelines specify higher limits for trace metals, as shown in Table 7-8 below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 89 Table 7-8: ANZECC water quality guidelines Constituent Upper Limit Cadmium (Cd) 36 µg/l Chromium (Cr) 85 µg/l Copper (Cu) 8 µg/l Lead (Pb) 12 µg/l Nickel (Ni) 560 µg/l Zinc (Zn) 43 µg/l Source: CSIR (2006b)
• Guidelines for suspended sediment concentrations in the water column from dredging activities at the West Coast of southern Africa developed by Embecon (2004). Embecon suggest that total suspended sediment concentrations below 100 mg/l represent limited risks for biota; and
• Guidelines for sediment with comparable levels of contamination to those in the BSD quoted by Geffard et al. (2002) (quoted in Lwandle 2006a), which indicate that significant toxicity effects may only be generated at 2000 mg/l suspended sediment. The suspended sediment concentrations thresholds applicable to the harbour are those of EMBECOM (2004) These identify exposures to 20mg/l for continuous periods of three days or longer as the lower threshold of possible adverse ecological effects. Probable adverse effects may be generated in exposures to 80mg/l but 100mg/l concentrations have proven negative impacts. This assessment utilises 20mg/l suspended sediment as a low risk threshold and 100mg/l as the upper permissible limit. The limited assessments of total suspended sediment concentrations that have been made in Cape Town harbour indicate that ambient levels are relatively high (average 30mg/l). It is inferred that both the biofouling community on the harbour walls and benthos in the sediment have accommodated this. The worst case scenario in terms of exceedance of the 20mg/l suspended sediment threshold demonstrated by the simulation modelling of turbidity plumes generated by the proposed dredging (CSIR 2006c) is illustrated in Figure 7.229 . This is expected to be caused by the cutter suction dredger at mid-depth. The figure shows that the turbidity plumes should be contained within the Ben Schoeman Dock and that the 20mg/l threshold may be exceeded for 5-10 days of the period modelled (90 days). The biota within the Ben Schoeman Dock may be exposed to suspended concentrations of ~50mg/l for 5-10 days during the dredging period. This is half the critical level identified by EMBECOM (2004).
29 Note that in this and all subsequent turbidity modelling figures referred to in this report, the number of days for which relevant sediment levels are exceeded related to the cumulative total of time during which these levels are exceeded within a 90 day period.
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Source CSIR 2006a Figure 7-2: Predicted exceedence (days) of 20mg/l suspended sediment concentration at mid-depth during cutter suction dredged operations. Benthos in the harbour is found to be impoverished in the majority of the area to be dredged and the generation of suspended sediment plumes in the dredge area over the dredge period and potential sublethal or lethal impacts on biological organisms and/or communities inhabiting the harbour sediments and structures is rated as being very low. Water quality modelling predicts that the thresholds will not be exceeded at any point outside the immediate dredge area, and that the potential effects should be limited to the duration of the dredging activity. Due to the limited extent of the impact mitigation is not considered necessary. An assessment of this impact “with mitigation” has thus not been provided below. Table 7-9: Significance of the potential generation of suspended sediment plumes and potential impact on biological organisms in the harbour
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very low Possible VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the generation of suspended sediment plumes in the dredge area and potential sublethal or lethal impacts on biological organisms and/or communities inhabiting harbour sediments and structures is therefore rated as very low .
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Impact 3: Settlement of material suspended during dredging and alteration of sediment characteristics and effects on sediment biota and ecological processes The harbour is by design a quiet water area and it is likely that the majority of the fines in dredge hopper overwash and those suspended by dredge head turbulence will resettle in the harbour. This may lead to inundation of sediment biota adjacent to the dredge areas, possibly altering community structure and/or disrupting ecological processes (e.g. by smothering benthos in the harbour sediments). As stated previously the harbour sediment community is relatively impoverished and may be kept that way by pollution and physical disturbance (e.g. sediment suspension) by shipping and stormwater outfalls into the harbour. Benthic macrofauna have been shown to survive short term inundation and examples of bivalve molluscs and gastropods have been found to migrate vertically up to 16cm when inundated with sand; with some amphipods, crabs and polycheates migrating vertically up to 30cm. Therefore given the generally slow sedimentation rates of fine particles, the probable non-unique biological community that is present and the ability of benthic macrofauna to survive relatively rapid sedimentation events, the maximum inundation depths predicted by simulation modelling of 5-10cm, significant disruption of the benthos in the harbour area is not expected. Due to the low significance of this impact, mitigation measures are not considered necessary. An assessment of this impact “with mitigation” has thus not been provided below. Table 7-10: Significance of potential settlement of suspended sediments and the effects on sediment biota and ecological processes.
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very low Definite VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential settlement of suspended sediment and the effects on sediment biota and ecological processes is therefore rated as very low .
Impact 4: Importation of alien species by dredgers and associated ecological effects Dredgers may transport alien biota in ballast water, in residual sediment in their hoppers or even attached as biofouling organisms on their hulls. The release of alien species into the Port of Cape Town by dredgers carries the risks of allowing the establishment of populations and potential competitive exclusion (food, space, nutrients) of indigenous species. In the worst case such imports may lead to the development of invasive populations with the capacity to severely disrupt and modify communities and ecological processes. Despite a long history of international shipping passing through South African ports there are only 16 confirmed cases of alien species becoming established in the country's coastal waters and/or ports. The best known of these is the Mediterranean mussel Mytilus galloprovincialis , currently the mainstay of the local mussel farming industry, the ascidian Ciona intestinalis , a biofouling organism common in harbours, and the European shore-crab Carcinus maenas . Other alien species that have or may exert deleterious effects on ecological processes or industries dependent on these include the harmful algal bloom dinoflaggelate species Alexandrium tamarense and Gymnodinium cf . mikimotoi
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 92 and the brown microalgae Aureococcus anophagefferens. In addition to these, 22 species are classified as 'cryptogenic', i.e. organisms with wide distributions suspected of being alien. The mussel and ascidian can be regarded as invasive in that they have replaced or displaced indigenous fauna and have economic implications. The other species have small, restricted populations. This notwithstanding, the Port of Cape Town is known to support established communities of ~ 5 alien species, and is also known to be inhabited by a range of cryptogenic species that have become established but do not possess large populations. The impact of the import and release of alien species by dredgers and their establishment in habitats within the harbour area is considered to be of a local-to-regional extent, with a possible extension to national significance. Impacts would be long term to permanent as, once established, it is unlikely that alien species would be obliterated by natural processes of competition, predation etc. The probability and thus the significance of this impact occurring can be mitigated through the application of the applicable ballast water management protocols stipulated in the International Maritime Organisation (IMO) International Convention for the Control and Management of Ship’s Ballast Water and Sediments, which have been shown to reduce viable organisms by 95%. Although the probability of the impacts occurring would be reduced, it must be noted that ballast water treatment measures would not address the risk resulting from residual sediments in these vessels. Rigorous flushing and washing of both dredger and barge hoppers may constrain the risks here but it is not clear how this can be achieved. Table 7-11: Significance of the potential importation of alien species by dredgers and associated ecological effects in the harbour
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Medium Long-term High Probable HIGH -ve Medium mitigation 2 2 3 7 With Regional Medium Long-term High Improbable LOW -ve Medium mitigation 2 2 3 7 The significance of the potential importation of alien species by dredgers and the associated ecological effects, assuming the implementation of mitigation measures, therefore rated as low . Note: Although the prescribed impact rating methodology results in a medium significance rating with mitigation, based on the experience and opinion of the specialists and EIA consultant, this impact is considered to be of low significance, primarily due to the existing risk posed by the large number of vessels entering the port from international waters.
7.3.3.2 Impacts on Dredge Spoil Disposal Sites In most cases, the impacts of the disposal of dredge spoil material on the dredge spoil site will differ for Site 1 and Site 2, and separate impact ratings have been provided for each site, to facilitate a comparative assessment of the suitability of each of the dredge disposal sites, in Chapter 8.
Impact 5: Deposition of discharged sediment and effects on benthic macrofauna The discharge of ~1.23 million m 3 of dredge spoil to the dredge spoil disposal site will inundate the resident benthos, possibly disrupting community structure and ecological processes at the site. The identified dump sites are approximately 3 km x 2 km in size which should result in an average inundation depth of 0.3m (30cm). Most of the major faunal classes in the benthos have been shown to be able to withstand such burial depths and once the dumped sediment has stabilised, it is likely
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 93 that fauna will both migrate into the spoil dump area and recruit to it with a relatively short recovery period. However, due to the spoil dumping practices followed by dredgers and/or barges carrying dredge spoil it is considered to be highly unlikely that an even distribution of dumped dredge spoil will be achieved. It is possible that there could be unevenness leading to mound heights that exceed 0.3 m. It is anticipated that localised mounds with peaks of up to 0.6 to 0.7 m could occur due to the nature of the proposed dredge spoil dumping and the difficulty in obtaining an even distribution of sediments over the dump-site. This could cause higher mortality levels in the benthos, in localized areas. Recovery periods should however be equally short. The two potential dredge spoil disposal sites differ in sediment properties and in benthos community structure. Consequently the potential impact of sediment deposition on the benthos is evaluated separately for each site. Site 1 Site 1 is characterised by a more or less uniform fine sand sediment and a high similarity in benthos community structure across the site. The 'worst case' average deposition pattern which would result from dredge spoil discharge during the use of a cutter suction dredger (based on simulation modelling undertaken by CSIR, 2006), would result in the bulk of the deposition occurring on the designated disposal site. The surrounding area, including the northern edge of the Table Mountain Marine Protected Area (MPA) is however also expected to receive dispersed sediment. Average depositional thickness is predicted to be low outside of the disposal site, however, ranging from 1cm-5cm. Most of the affected area within the MPA will have deposition <1cm in thickness, as indicated in Figure 7-3 below.
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Source: CSIR 2006 Figure 7-3: Predicted mean thickness of deposition at dump Site 1 for the cutter suction dredger The deposition of dredge spoil at Site 1 may thus smother benthos on the dredge spoil site and adjacent areas, resulting in benthos mortality and disrupting ecological processes. These impacts would occur on a local scale, and be restricted to within a 5km radius of the centre of the spoil site. Although some organisms may burrow to the surface after being covered by sediment, burial depths may prevent this on the disposal site itself. Biomass at the disposal site would thus be reduced and the community structure altered. Deposition depths outside the dump site are insignificant and there should be limited effects on the benthos inhabiting these areas. The spatial extent of the impacts is expected to be relatively small compared to the amount of similar habitat in Table Bay. In addition, the impacts are expected to be short-lived, with rapid recolonisation (1-3 years) as most of the sediment being dumped is similar to that already in the area.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 95 It is recommended (see Section 7.7.5) that during sediment discharge, sediment is deposited in thin layers, which would decrease the mortality of benthos, and could make this impact insignificant. As this is however not an essential mitigation measure, and the implementation cannot be guaranteed, the reduced significance of the impact has not been reflected in the assessment table below. Table 7-12: Significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 1
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Medium Short-term Very Low Probable VERY LOW -ve High mitigation 1 2 1 4 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 1 is therefore rated as very low. Site 2 The 'worst case' average deposition pattern which would once again result from dredge spoil discharge during the use of a cutter suction dredger (based on simulation modelling undertaken by CSIR, 2006), at Site 2, is depicted in Figure 7-4. Similar to Site 1, the bulk of the discharged sediment is contained within the designated disposal site. However, there is an extensive area outside the disposal site where deposition of sediment occurs, albeit in shallow layers (<1cm thick). Some of this deposition extends into the coast adjacent and south of Mouille Point, in the Table Mountain National Park MPA.
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Source: CSIR 2006 Figure 7-4: Predicted mean thickness of deposition at dump Site 2 for the cutter suction dredger Site 2 has a wider range of sediment properties that have a patchy distribution across the site than found at Site 1. There is a matching higher dissimilarity in benthos community structure. The site also has exposed rock on it supporting its own biological community. Coarse sediments and rock surfaces have longer recolonisation periods than fine sands (estimated at approximately 5 years). Although data is limited, it would appear from detailed bathymetry that the conditions at Site 2 are less widely distributed in Table Bay than those of Site 1, making it a more unique habitat. The deposition of dredge spoil at Site 2 may smother benthos on the dredge spoil site and adjacent areas, resulting in benthos mortality and disruption of ecological processes. Although the actual effect may be restricted to areas on and adjacent to the disposal site, the habitat is not known to be
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 97 widely distributed in Table Bay and/or the wider region. The fact that deposition will extend into Table Bay may also affect low relief emergent rock surfaces evident in detailed bathymetric charts of the area. As a result the impact would be considered to be of regional significance. Although some organisms may burrow to the surface, burial depths may prevent this on the dump site itself. This would result in a reduction in biomass and the community structure being altered. Deposition depths outside of the dump site are insignificant but the seafloor in this area may be rock rather than sand, and deposition of sediment may thus alter the biological structure on these surfaces. The duration of these impacts would be medium term, with rocky environments requiring a recovery time of approximately 5 years. As no mitigation can be recommended to reduce the significance of these impacts, other than not making use of this site for disposal of dredge spoil, no assessment of the impact with mitigation has been provided. Table 7-13: Significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 2
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Medium- Regional Medium Medium mitigation term Probable MEDIUM -ve High 2 2 6 2 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of sediment deposition on benthic macrofauna at dredge disposal Site 2 is therefore rated as medium.
Impact 6: Alteration of benthic biological communities through toxins associated with dredge spoil The dredge spoil is characterised by trace metal concentrations higher than the London Convention special care (action level) thresholds and threshold effect levels (TEL), although they do not exceed the prohibition thresholds (i.e. levels above which they may not be disposed of at sea). Dredge spoil therefore has the potential to alter benthos community structure on the site used for spoil disposal and immediately adjacent areas, as a result of the contamination of the sediments. The toxicity potential of the dumped sediments depends on the bioavailability of trace metals which are expected to be limited due to probable adsorption to iron (ferric) and manganese (manganous) hydroxides present in the now oxic sediments (and based on elutriation tests undertaken). Trace metals should thus remain in the particulate phase. If the sediment is sufficiently toxic to cause adverse effects, the toxicity is likely to be relatively rapidly dissipated by wave generated resuspension and advection of silt and clay sized particles away from the dump site area (having a dilution effect, and thus reducing the possibility of toxic effects). Re-deposition of these sediments away from the dump site should be sufficiently small to mitigate any latent toxicity. Therefore any toxic effects on biota in and adjacent to the dump site should be worked out of the community within a few generations. The probability of toxic effects occurring are considered to be low, as there is only a single instance of a trace metal in the sediments to be dredged exceeding the probable effect level (PEL), and this
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 98 should be reduced below this threshold once disposed of through dilution with less contaminated sediments and the spoil dumping process. Because of differing benthos community structure in the two potential dredge disposal sites implications of potential toxic effects would differ, and the significance of the potential impact on these two sites have therefore been assessed separately. Site 1 As the sediment deposition at Site 1 will largely be limited to the immediate area of the dump site, as indicated in Figure 7-2 the extent of the potential toxic effects on benthic biological communities impacts would be local. The significance of this impact is considered to be very low, due to the spatial and temporal extent of any effect being small relative to the amount of similar habitat in Table Bay and no mitigation measures are considered necessary or feasible. No assessment of this impact with mitigation has thus been provided. Table 7-14: Significance of the potential alteration of benthic biological communities through toxins in dredge spoil at Site 1
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very Low Improbable VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential alternation of benthic biological communities through toxins in dredge spoil at dredge disposal Site 1 is therefore rated as very low . Note: Although the prescribed impact rating methodology results in a significance rating of “insignificant”, based on the experience and opinion of the specialists and EIA consultant, this impact is considered to be of very low significance. Site 2 The significance of this impact at Site 2 is considered to be higher than at Site 1. Although the actual effect may be restricted to the areas in and adjacent to the dredge disposal site, the habitat existing at this site may not be widely distributed in Table Bay and/or the wider region, and the influence of this impact occurring may thus be considered regional. There is a potential biodiversity “loss” due to the possible uniqueness of the habitat in Table Bay and the fact that only part of the area has sediment similar to that proposed for dumping. As no mitigation, other than not making use of this site for disposal of dredge spoil, can be recommended to reduce the significance of these impacts, no assessment of the impact with mitigation has been provided. Table 7-15: Significance of the potential alteration of benthic biological communities through toxins in dredge spoil at Site 2
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Low Short-term Very Low Improbable LOW -ve High mitigation 2 1 1 4 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential alternation of benthic biological communities through toxins in dredge spoil at dredge disposal Site 2 is therefore rated as low .
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 99 Note: Although the prescribed impact rating methodology results in a significance rating of “insignificant”, based on the experience and opinion of the specialists and EIA consultant, this impact is considered to be of low significance.
Impact 7: Effects of turbidity generated by the dredge spoil dumping on habitats adjacent to the dredge spoil dump area(s) The suspended sediment concentrations thresholds applicable to the dredge spoil dump sites are those of EMBECOM (2004). These identify exposures to 20mg/l for continuous periods of three days or longer as the lower threshold of possible adverse ecological effects. Probable adverse effects may be generated in exposures to 80mg/l but 100mg/l concentrations have proven negative impacts. This assessment utilises 20mg/l suspended sediment as a low risk threshold and 100mg/l as the upper permissible limit. Simulation modelling of suspended sediment distributions in the surface layers of the water column show that levels >20mg/l do not extend beyond the borders of either of the dredge spoil dump sites for any of the dredging scenarios tested. This is not the case for the bottom layer as shown in Figures 7.5 and 7.6. These are the 'worst case' predictions and apply to the winter “combination cutter suction dredger and backhoe” scenario. (Scenarios for “combination Trailing suction hopper dredger and backhoe” dredging operations are slightly less severe but those for backhoe only dredging much smaller due to lower spoil dump rates.)
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Source: CSIR 2006a Figure 7-5: Predicted exceedance (days) of 20mg/l of suspended sediment within the bottom layer of the greater study area for the dredge spoil dumped at Site 1 (worst case scenario) Figure 7.5 indicates that turbid water near the sea floor may invade large areas of Table Bay; mostly within a ~5km radius of the centre of disposal Site 1 but there is also a patch of longer exceedances of the 20mg/l threshold in inner Table Bay, north of the harbour entrance. Exceedances in these areas are predicted to be >15<30 days indicating a strong likelihood that exposure durations may be
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 101 longer than three days. There is therefore a possibility of deleterious impacts within these areas. The number of days when the threshold is exceeded outside of these areas is low (2-5 days) and durations in excess of 3 days are considered to be unlikely with a low probability of deleterious effects. Sediments disposed of at dredge disposal Site 2 have a far greater area of impact and higher days of exceedance than at disposal Site 1, as indicated in Figure 7.6.
Source: CSIR 2006a Figure 7-6: Predicted exceedance (days) of 20mg/l of suspended sediment within the bottom layer of the greater study area for the dredge spoil dumped at Site 2 (worst case scenario)
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 102 The simulation modelling predicts that a large proportion of the Table Bay seabed, and associated biota, will be exposed to suspended sediment concentrations >20mg/l for >30 days. According to the adopted thresholds of possible adverse ecological effects, disposal of dredge spoil at Site 2 under this scenario therefore has negative implications for an appreciable proportion of the Table Bay benthos. Whereas exceedance of the 20mg/l suspended sediment threshold for dredge spoil dumping at both dump sites is extensive in Table Bay, that for the 100mg/l limit is not, being largely contained within the site boundaries. However, the area affected is larger for Site 2 than for Site 1 (Figures 7.7 and 7.8) which is probably a function of depth differences. Therefore the areas of probable adverse ecological effects of suspended sediments on benthos are mainly limited to the specific dump sites and may be exerted on biota already compromised by inundation (as discussed above). However, Site 2 has a larger area of probable effects associated with it, extending northwards towards Robben Island.
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Source: CSIR 2006a Figure 7-7: Predicted exceedance (days) of 100mg/l of suspended sediment in the bottom layer of the greater study area for Site 1 (worst case scenario)
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Source: CSIR 2006a Figure 7-8: Predicted exceedance (days) of 100mg/l of suspended sediment in the bottom layer of the greater study area for Site 2 (worst case scenario) Due to the apparent differences in areal scales of potential impacts of suspended sediments the two dredge spoil dump sites are assessed separately. Site 1 The negative effects of turbid plumes as a result of dredge spoil disposal at Site 1 would be local, largely restricted to within an approximately 5km radius of the centre of the spoil dump site but with
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 105 an isolated patch of longer exceedances immediately north of the harbour entrance. Durations of exceedances of concentrations above the 20mg/l threshold outside of these areas are probably <3 days and concentrations >100mg/l are predicted to be restricted to the dump site and immediately adjacent areas. The effects of turbidity on habitats is expected to be short-lived, with recovery commencing on completion of the dredging programme, and largely attained within 1-3 years. Due to the small spatial extent of the effects relative to the amount of similar habitat in Table Bay and the expected rapid recolonisation, this impact is considered to be insignificant, and no mitigation is required. Table 7-16: Significance of the potential effects of turbidity from dredge spoil disposal on habitats adjacent to Site 1
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very Low Possible INSIGNIFICANT -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of turbidity from the disposal of dredge spoil on habitats surrounding the dredge disposal Site 1 is therefore rated as insignificant. Site 2 The negative effects of turbid plumes as a result of dredge spoil disposal at Site 1 would be Regional; as a large proportion of the Table Bay sea floor will be exposed to suspended sediment concentrations above 20mg/l for periods exceeding the set three days of continuous exposure limit and concentrations >100mg/l are predicted to affect the seabed north of the dump site itself. The effects may lead to temporary shifts in community structure, which may have implications for biodiversity because of the diversity of habitats that may be affected. The impact is considered to be of medium significance, as the potential spatial extent of the impact is large relative to the known distributions of habitat types and Table Bay itself. However, recolonisation should be rapid. No viable essential mitigation measures have been identified to reduce the significance of this impact (other than not making use of this disposal site), and no assessment with mitigation has been provided. Table 7-17: Significance of the potential effects of turbidity from dredge spoil disposal on habitats adjacent to Site 2
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Medium Short-term Low Probable MEDIUM -ve Medium mitigation 2 2 1 5 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of turbidity from the disposal of dredge spoil on habitats surrounding the dredge disposal Site 2 is therefore rated as medium. Note: Although the prescribed impact rating methodology results in a low significance rating, based on the experience and opinion of the specialists and EIA consultant, this impact is considered to be of medium significance.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 106 Impact 8: Effects on water quality in the Table Mountain National Park Marine Protected Area and resulting effects on biota as a result of sediment plumes Simulation modelling of the generation of sediment plumes as a result of the disposal of dredge spoil indicate that in the worst case scenario (winter making use of the cutter suction dredger), suspended sediment concentrations greater than the 20mg/l possible effect threshold may invade the bottom waters of the Table Mountain National Park MPA and the Robben Island exclusion zone, as indicated in Figures 7-5 and Figure 7-6 respectively. Suspended sediment concentrations >100mg/l (the probable effect level) are predicted not to extend into the Table Mountain National Park MPA for sediments discharged at dredge disposal Site 1 for longer than a day 30 (Figure 7.7) but may well do so for spoil discharged at Site 2 (Figure 7.8) with respect to the Robben Island exclusion zone. This is not expected to occur for Cutter Suction Dredger operations in summer or for any of the other dredging scenarios tested. The predicted 'worst case' simulated time series of bottom water suspended sediment concentrations at 0.5 km and 1 km south of the northern boundary of the MPA for both dredge spoil disposal sites show that, for disposal at Site 1, there are two occurrences of suspended sediment concentrations in excess of 20mg/l that have durations in excess of three days immediately south of the dump site. The durations are similar at the 0.5 km and 1 km locations but peak concentrations are higher deeper into the MPA. Exceedances southwest of Site 2 are marginal and short lived. The maximum exposure period in the simulations appears to be ~seven days. For dredge disposal at Site 2, there will be less frequent occurrences of suspended sediment concentrations >20mg/l and none of these are predicted to have durations in excess of three days. For disposal at either of the sites, suspended sediment concentrations >20mg/l are predicted to extend into the Karbonkelberg sanctuary area within the Table Mountain National Park MPA (Figures 7.5 and 7.6). However, the number of days of exceedance is low at less than two days for Site 1 and less than five days for Site 2. The three day duration threshold will not be transgressed for the latter dump site. The potential impact of high suspended sediment concentration water invading the Table Mountain National Park MPA and/or the Robben Island exclusion zone for the two dredge spoil disposal sites is assessed separately for the dump sites below. Site 1 Although the potential effects on water quality in the Table Mountain National Park MPA and/or Robben Island exclusion zone, and potential resultant effects on biota would be limited to the northern area of the Table Mountain National Park MPA, these would be considered of regional extent, due to the regional importance of the MPA. Effects would be short-lived, and likely to extend only over the duration of the Cutter Suction Dredging phase. This impact is thus considered to be insignificant. Undertaking dredging with Cutter Suction Dredgers during summer would however reduce the impacts, as the penetration of >20mg/l suspended sediment load into the Table Mountain National Park MPA is reduced, and is not
30 It should be noted that durations of sediment plumes are related to total duration associated with multiple sediment disposal events within a 90 day period.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 107 expected to reach the Karbonkelberg sanctuary area. As this can however not be guaranteed, assessment with the implementation of this mitigation measure has not been provided. Table 7-18: Potential effects on water quality in the Table Mountain National Park MPA and resulting effects on biota as a result of sediment plumes for disposal at Site 1
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Low Short-term Very Low Possible Insignificant -ve Medium mitigation 2 1 1 4 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of turbidity from the disposal of dredge spoil on water quality and thus biota in the Table Mountain National Park MPA and/or Robben Island exclusion zone as a result of disposal of dredge spoil at Site 1 is therefore rated as insignificant. Site 2 The potential effects on water quality and potential resultant effects on biota in the case of disposal at Site 2, may be exerted in both the Table Mountain National Park MPA and the Robben Island exclusion zone with the latter being probable due to the penetration of suspended sediment concentrations in excess of 100mg/l into the western and southern sections. These areas are of regional significance, and the extent of the impact would thus be considered regional. Effects would be short-lived, and likely to extend only over the duration of the Cutter Suction Dredging phase. The probability of the effect occurring is higher for the Robben Island exclusion zone than for the Table Mountain National Park MPA. This impact is considered to be of low significance, but could be mitigated by not making use of this dredge disposal site. As this is however not considered an essential mitigation measure, this has not been considered in the assessment table below. Table 7-19: Potential effects on water quality in the Table Mountain National Park MPA and resulting effects on biota as a result of sediment plumes for disposal at Site 2
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Medium Short-term Low Probable Low -ve Medium mitigation 2 2 1 5 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of turbidity from the disposal of dredge spoil on water quality and thus biota in the Table Mountain National Park MPA and/or Robben Island exclusion zone as a result of disposal of dredge spoil at Site 2 is therefore rated as low.
Impact 9: Introduction of alien species to dredge disposal sites Dredgers may transport alien biota in ballast water, in residual sediment in their hoppers or even attached as biofouling organisms on their hulls. The release of alien species into Table Bay by dredgers carries the risks of allowing the establishment of populations and potential competitive exclusion (food, space, nutrients) of indigenous species. In the worst case such imports may lead to the development of invasive populations with the capacity to severely disrupt and modify communities and ecological processes.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 108 The potential exists for importing alien species to the dredge disposal site, although this risk should be limited to the first spoil dump events. After these any alien species that may have been in the hoppers should have been released. There is an existing risk of this occurring due to current vessels entering Table Bay, however the existing risk may not be specifically linked to the proposed dredge disposal sites. The import and release of alien species by dredgers and their establishment at and/or adjacent to the dredge spoil disposal area would have a similar effect at either of the two sites being considered, and a single assessment is thus valid for both sites. This impact, should it occur, would be considered to be of local to regional (within Table Bay) and possibly national significance. Once established it is unlikely that alien species would be obliterated by natural processes of competition, predation etc, and the impact would thus be expected to have long-term to permanent effects. The probability of this impact occurring (although not the significance) can be reduced through the application of the applicable ballast water management protocols stipulated in the IMO International Convention for the Control and Management of Ship’s Ballast Water and Sediments, which have been shown to reduce viable organisms by 95%, as well as the relevant requirements of NPA’s Ballast Water Management Plan. Although the probability of the impacts occurring would be reduced, it must be noted that ballast water treatment measures would not address the risk resulting from residual sediments in these vessels. Rigorous flushing and washing of both dredger and barge hoppers may constrain the risks here but it is not clear how this can be achieved. Table 7-20: Significance of the potential importation of alien species by dredgers and associated ecological effects at dredge disposal sites
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Medium Long-term High Possible MEDIUM -ve Medium mitigation 2 2 3 7 With Regional Medium Long-term High Improbable MEDIUM -ve Medium mitigation 2 2 3 7 The significance of the potential importation of alien species by dredgers and associated ecological effects at the dredge disposal site is therefore rated as medium.
Impact 10: Effects of turbidity generated during dredge spoil dumping on endangered coastal seabirds, specifically the African Penguin Spheniscus demersus The African Penguin (included in the red data list of endangered species) forages in the areas of the proposed dredge spoil dump sites and there is a breeding colony on Robben Island. A marked decline in the global breeding population size from ~22 000 pairs in 1987 – 2001 to ~11 000 pairs in 2003 – 2006 has occurred recently. This has placed the African Penguin population in a precarious situation in terms of its survival in the wild and potential disturbances on penguins therefore have to be strictly guarded against. Penguins are visual hunters and reduced visibility in the upper water column can reduce foraging success, although it is unknown at what level turbidity begins to influence foraging. However, for the purposes of this assessment a lower concentration limit of 10mg/l total suspended solids above background in surface waters, i.e. the concentration at which the associated plume becomes visible is considered to be the threshold which begins to interfere with penguin foraging.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 109 The predicted 'worst cases' for upper water column turbidity for the proposed dredge spoil disposal at both dump sites indicate that 10mg/l suspended sediment concentrations will be exceeded for <5 days in the immediate vicinity of the dump sites and an area immediately north of Mouille Point. These are small proportions of the proposed dredging period and the water surface in Table Bay. Elevated turbidity levels are likely to be of short duration, but possible deleterious effects on the local penguin population level could be long term to permanent due to the small population size. It should however be noted that there are no explicit links between turbidity, foraging success and population level effects and the level of confidence for the evaluation of this impact is thus low. In such a case, however the precautionary approach needs to be taken. Due to the small area affected in the case of disposal at either of the two potential dredge disposal sites as well as the expected turbid plume dissipation rates the significance of this impact is rated as low without mitigation. Essential under any interpretation of the application of the precautionary principle embodied in NEMA and the Biodiversity Conservation Act of 2002, it is recommended that care is taken to ensure that there is no chronic build up of turbidity in the area of the dredge disposal site through allowing sufficient time for turbidity to disperse between dump events. The implementation of this mitigation measure would reduce the intensity of the impact, thus reducing the significance of the impact to very low. As the exact requirements in this regard cannot be provided based on current information and the implementation of this mitigation measure cannot be guaranteed, the assessment of this impact with mitigation has not been presented in the table below. Table 7-21: Significance of the potential effects of turbidity during dredge spoil dumping on endangered coastal seabirds
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Medium Short-term Low Improbable LOW -ve Low mitigation 1 3 1 5 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential effects of turbidity resulting during the disposal of dredge spoil at either of the dredge spoil disposal sites on endangered coastal seabird, especially the African Penguin, foraging in the area is thus rated as low . Note: Although the prescribed impact rating methodology results in a very low significance rating, based on the experience and opinion of the specialists and EIA consultant, as well as implementation of the precautionary principle this impact is considered to be of low significance.
Impact 11: Potential erosion of shoreline as a result of dumping of dredge material The potential effects of the project on shoreline stability in Table Bay would be limited to those associated with disposal of the dredge spoil at the selected disposal site. Dredging activities are contained within the Ben Schoeman Dock and are not expected to affect the local wave conditions or shoreline of Table Bay. The disposal of dredge spoil from the Ben Schoeman Dock at either of the potential dredge disposal sites would result in changes to the character of the sea bed at the disposal site, including the depth, depending on the height of the sediment mound created. Although initially assumed that a mound of approximately 0.3m average height would result from the dredge spoil disposal, it is recognized that
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 110 given the uneven distribution of the dredge material, it is possible that there could be unevenness leading to mound heights that exceed 0.3 m. It is anticipated that localised mounds with peaks of up to 0.6 to 0.7 m could occur due to the nature of the proposed dredge spoil dumping and the difficulty in obtaining an even distribution of sediments over the dump-site. This is unlikely to cause problems if these are isolated and not too extensive. A mound of material of this height could affect the shoreline as a result of the effect of wave refraction. Variation in the bathymetry of the sea bed close to the shore, such as that which would result from a mound of disposed material can affect both the height and direction of the waves reaching the shoreline. Such changes in wave conditions could cause changes in the rate of longshore sand transport, thus potentially affecting the average shoreline position, through erosion or accumulation of sand on a seasonal basis or even on a longer timescale. The dimensions of the mound would determine the effect of the wave refraction, while the longevity of the mound would determine how long any wave refraction effects persist. Due to the distance of the potential dredge disposal sites from the shoreline, it is not expected that disposed material would affect the shoreline by serving as a source of sand. Refraction effects resulting from a local change in bathymetry of the seabed diminish with distance. Previous studies indicate that e.g. erosion in the order of 0.5m may be induced at a distance of up to 4km from the dredge dump site but would be negligible at a distance of 9km from the dump site. Site 1 The results of an analysis of the potential effects of dredge disposal on the sandy beaches in Table Bay indicated that minor erosion (on average 0.5m) could result from a sediment mound with a height of 0.3m above the sea bed. The effects of a mound in 40m depth (with an average elevation of 0.3m) were found (as described below) for Site 2 to cause negligible shoreline erosion, and it can be inferred that a similar mound dumped at a depth of ~65m would also have a negligible effect since the effects of refraction diminish with water depth. Changes to longshore sediment transport that consequently could affect shoreline stability (i.e . result in minor shoreline erosion and/or accretion) is much less likely for the greater water depths at Site 1 than for the shallower Site 2. As no impact is expected in the case of dredge spoil disposal at Site 1, no mitigation is considered necessary. Table 7-22: Significance of the potential erosion of the shoreline as a result of dredge disposal at Site 1
Extent Intensity Duration Consequence Probability Significance Status Confidence Without None None None Not Improbable INSIGNIFICANT neutral High mitigation 0 0 0 Significant With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential erosion of the shoreline as a result of dredge disposal at Site 1 is thus rated as insignificant .
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 111 Site 2 The results of an analysis of the potential effects of dredge disposal on the sandy beaches in Table Bay indicated that minor erosion (on average 0.5m) could result from a sediment mound with a height of 0.3m above the sea bed. However, recognizing that Site 2, at a depth of ~40m is about 9km from the sandy erodible shoreline, the decay of wave refraction effects over this distance would result in negligible (i.e. in the order of centimeters at most) erosion effects on the shoreline. In the case of any effects occurring, these would be on a local scale, and considered to be of low intensity with natural functions and processes on the beach, in terms of amenity, protection afforded to property and structures and functioning of dune and beach ecosystems negligibly altered. Any potential impacts which could occur would be expected to be of medium term duration. Any minute shoreline erosion would become virtually non-existence within 2-15 years as a result of erosion of the mound. It should be noted that the assessment of this impact assumes an average conservative mound height of 0.3m, although the possibility of isolated peaks is recognised. Isolated peaks in mound height above this elevation are unlikely to affect wave conditions, provided that these peaks are limited in number and size. Mitigation of possible erosion, which would be in the order of centimeters if it occurred, would not be considered essential. The only practical means of mitigation would be the periodic supply of sand to the beach. It is very likely that sufficient sand of suitable size characteristics would be available to mitigate a minor erosion effect if desired, thus eliminating the impact. As this mitigation can however not be guaranteed, the assessment of this impact with mitigation has not been presented in the table below. Table 7-23: Significance of the potential erosion of the shoreline as a result of dredge disposal at Site 2
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Medium- Local Low Very Low mitigation term Possible INSIGNIFICANT -ve High 1 1 4 2 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential erosion of the shoreline as a result of dredge disposal at Site 2 is thus rated as insignificant .
7.3.3.3 Impacts on existing uses in Table Bay
Impact 12: Potential deposition of sediments from dredging operations in existing dredge areas and/or navigation channels There is a concern that the dredge material disposed of at the dredge disposal sites may be transported into the bay and be deposited in existing dredge areas and/or navigation channels, thus requiring a degree of maintenance dredging to maintain channel depths. The model results however indicate this impact to be small and greatly reduced in winter, when little or no sediments are predicted to settle in the entrance channel to the Port of Cape Town.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 112 Model simulations of the movement of sediments in the Port during dredging and around the potential dredge disposal sites as a result of disposal of dredged material indicate that deposition in the outer extremity of the port entrance channel does not exceed 1cm in the case of disposal of dredge spoil at Site 1 and 5cm for disposal at Site 2. Closer to the harbour entrance sedimentation does not exceed 0.5cm for disposal at Site 1 and 1cm for disposal at Site 2. These are however considered to be conservative estimates (i.e. are expected to be lower than estimated). As the sediments will continue to the redistributed for an extended period of time, the duration of this impact is considered to be medium term. Although long term changes to navigation channels and dredge areas within the bay cannot be accurately estimated based on the short simulations (resulting in low to medium confidence), the probability of substantial movement of materials other than muds towards the port entrance channel is greatly reduced for Site 1 compared to Site 2, although the impact ratings would be considered similar. A single assessment table, applicable to both disposal sites has thus been provided. No mitigation measures can be implemented for this potential impact, other than maintenance dredging of the potentially affected areas, if considered necessary. As such dredging is not considered essential, or proposed as part of the current project, an assessment assuming the implementation of this mitigation measure has not been provided. Table 7-24: Significance of the potential deposition of sediments from the dredging operations in existing dredge areas and/or navigation channels
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Medium- Local Medium Low Low to mitigation term Probable LOW -ve 1 2 5 medium 2 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential deposition of sediments from the dredging operations in existing dredge areas and/or navigation channels is thus rated as low .
Impact 13: Interference with existing shipping During the intensive dredging operations, between 8 to 10 hopper barge loads per day will be moving between the dredger in the harbour and the dredge disposal site. As a result of the increase number of barges moving between the port and the dredge spoil site, there is a risk that this would interfere with existing shipping traffic entering and exiting the port, as well as increase the risk of collision between vessels. Furthermore there is a remote possibility that there may be break-down (e.g. stuck hopper doors) that would result in the hopper barges occupying the navigational channels and entrance to the port and, in so doing, interfere with other ships making use of the port. The potential impact is local in scale; however, should there be a collision of vessels, the consequences could be regional. Consultations with the South African Maritime Safety Association and the Port Captain have indicated that the proposed dump sites, while carrying some risk in terms of shipping (particularly in the case of dredgers or hopper barges breaking down) are acceptable and that the associated risks can be managed.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 113 Existing port shipping management systems should allow for the movement of vessels to be suitably managed, resulting in an impact of very low, which would be limited to the duration of the dredge operations. No mitigation would be required to reduce this impact, and an assessment with mitigation has thus not been provided in the table below. Table 7-25: Significance of the potential interference with existing shipping
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very Low Definite VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential interference with existing shipping is thus rated as very low .
7.3.4 Cumulative Impacts on the Marine Environment The proposed dredging operations will take place in a high shipping traffic working port that receives contaminants from ship operations, bunkering, urban stormwater flows and ship repairs amongst other sources. The port can therefore not be considered as a 'pristine' environment in any sense and it probably does not have any functional ecological links with Table Bay, aside from providing rock lobster habitat on the outer port structures. Therefore disturbances associated with the proposed dredging within the port are considered to be unlikely to exert any cumulative effects on the already compromised ecological functioning of the harbour, or in Table Bay. Further, possible cumulative effects on the natural environment associated with increased shipping in the Table Bay area are likely to be negligible and not discernible within the range of effects already generated by the high shipping traffic. None of these possible effects are considered further here. Table Bay receives effluent from stormwater flows and rivers draining the urban catchment of Cape Town, the Chevron/Caltex outfall at Milnerton and the Green Point and Robben Island outfalls that discharge primarily domestic effluent. Despite the pollution loads any ecological effects in the subtidal areas of Table Bay would appear to be limited as evidenced by environmental surveys conducted for the Chevron/Caltex outfall and the benthos community distributions determined in this assessment (above). Transferring contaminated sediment from the proposed dredge area to one of the candidate dredge spoil dump sites would add to this pollution load. Effects may be expressed at the dredge spoil dump site through long term (> 5 years) modification of benthos community structure or in the build up of contaminants in important components of the local benthic food chain such as mussels. The system-wide ecological consequences of this remain unknown, however and cannot be assessed with any degree of confidence.
7.3.5 Recommended Mitigation Measures: Potential Marine Impacts Essential mitigation measures include: 1. Apply the relevant ballast water management protocols stipulated in the IMO International Convention for the Control and Management of Ship's Ballast Water and Sediments as well as NPA requirements for ballast water management, with verification of application; and 2. Dispose of dredged material in such a way that an average mound elevation of 0.3m is achieved in order to prevent unexpected wave refraction effects occurring, particularly at Site 2.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 114 3. Include specifications of turbidity levels not to be exceeded at the entrance/exit to Ben Schoeman Dock in the Environmental Management Plan and Dredge Tender documents. Recommended levels are likely to range from 80 to 100mg/l, but will need to be both reasonable and sufficiently conservative to mitigate specific predicted environmental impacts. It is best left to the dredge operators to select appropriate mitigation measures to meet these specifications, rather than specifying these in the Environmental Management Plan. The EMP should however make allowance for monitoring of these levels. Optional mitigation measures include: 1. Lure seals, marine mammals and marine birds out of Ben Schoeman Dock to sea during blasting periods. 2. Should a Cutter Suction Dredger be chosen, undertake dredging during summer rather than winter; 3. Ensure that sediments are deposited in thin layers when discharged at the sediment disposal site, in an attempt to achieve a fairly even sediment distribution, rather than mounds, to reduce mortality of benthos; 4. Prevent the chronic build up of turbidity in the area of the dredge disposal site through allowing sufficient time for turbidity to disperse between dump events, thus reducing impacts on penguin populations foraging in the area; 5. Dispose of dredge spoil at Site 1 rather than Site 2; 6. In the case of Site 2 being selected as the dredge disposal site, undertake a limited wave modelling study for this site, to confirm the effect of uneven dumping on the wave climate is sufficiently limited to prevent changes in shoreline stability; 7. Reassess the potential impacts on the marine environment in the case of dredge technology, nature of operations or durations being significantly different to those assessed in the specialist study (based on current project description provided in Chapter 3); 8. Confirm the potential remobilization of toxins with additional (more comprehensive) elutriation analyses of the sediments targeted to be dredged, prior to dredging; 9. If possible, find a beneficial use for rock to be removed from the basin; 10. Obtain an appropriate environmental baseline for the potential impacts from dredging operations (e.g. water quality at the Two Oceans Aquarium intake). The baseline should specifically be obtained for “indicator” trace metals (copper and zinc) and suspended sediments (and possibly nutrient, particularly ammonium levels). These quantities are to be appropriately monitored at the Two Oceans Aquarium during the dredging operations; 11. In the case of water quality at the intake point not being suitable for use by the aquarium and attributable to dredging or dredge disposal activities, the implementation of mitigation measures (e.g. running of a closed system, or obtaining seawater from elsewhere) should be considered; Optional monitoring with respect to marine impacts include: 1. Utilise survey data gained on the candidate dump sites to track changes associated with dredge spoil dumping over a realistic time span to show rates of benthos recovery and provide information on dumped dredge spoil behaviour. Opportunities for this have not been created in
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 115 the past and the baseline data set will be an invaluable tool in understanding the effects and implications of the marine disposal of dredge spoil on South Africa's inner continental shelf. 2. Undertake further simulation modeling analyses of the life cycles and distributions of dredge spoil dump site surface layer turbidity plumes throughout the various phases of the dredging programme. In terms of the possible effects on African Penguins foraging in Table Bay, this may lead to mitigation solutions based on timing of the various phases of dredging and spoil dumping. Although the evaluation of the predicted effects on penguins yielded a low significance rating, public perceptions merit serious attention being given to efforts to ameliorate any possible impacts. 3. Monitor beneficial use areas of the V&A waterfront such as filter performance levels at the Two Oceans Aquarium and through real time monitoring (instrumented buoy and telecommunication system) located near the entrance to the harbour. The buoy system would also allow real time control of the dredging operations in terms of limiting exceedances of critical suspended sediment concentrations such as those envisaged in EMBECON (2004). 4. Operate a mussel watch programme (through DEAT/MCM) that incorporates sampling points around the Port of Cape Town. Sampling intervals in this programme are six months. During the dredging period it is recommended that monthly coverage is requested to show short term effects, if any, of remobilised contaminants in filter feeders. This monitoring can be augmented by suspension of mussels adjacent to the selected dredge spoil dump site to confirm that released or remobilised contaminants are below any level of concern. 5. Utilise the monitoring of the proposed dredging operation, together with supplementary measurements, to better constrain uncertainties in the model predictions. In particular, measurements supporting the more accurate specification of critical shear stresses of deposition, critical shear stresses of erosion and re-suspension rates at the seabed, should be taken.
7.4 Potential Noise, Shock and Vibration Impacts
7.4.1 Noise, Shock and Vibration Study Introduction, Terms of Reference and Methodology This section of the report is based on the Noise and Vibration Impact Assessment, attached as Appendix D, which was undertaken by Demos Dracoulides and Associates (DDA). The purpose of the Noise and Vibration Impact Assessment was to estimate the noise emissions and vibration associated with the proposed construction and dredging operations and assess the associated impacts on the adjacent areas and communities.
• Specific terms of reference for the noise and vibration study were to:
• Identify the most significant sources of noise vibration and shock during the construction and operation of the proposed project (including frequency and nature of these noises);
• Identify the main receptors for noise impacts (e.g. surrounding communities and businesses);
• Analyse noise impacts on the ambient (current) noise environment;
• Assess the impacts of vibration and shock on existing port infrastructure;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 116 • Assess the cumulative impacts of noise associated with simultaneous construction activities from the BSD and berth upgrade; and
• Provide general recommendations for the mitigation of the noise and vibration impacts. The approach for the noise study incorporated the measurement of daytime and night-time ambient noise at six locations, five within the perimeter of the port and one in the adjacent Zonnebloem residential area, since it has a direct line of sight with the BSD, where the construction activities will take place. The noise levels within and around the port area, due to all the construction equipment and operations, were estimated with the use of the internationally accepted MITHRA prediction software package. The determination of the sound power levels for the various equipment to be used during the construction operations were based on:
• the latest update of the equipment database included in the British Standard 5228: Part 1: 1984 “Noise Control on Construction and Open Sites Part 1: Code of Practice for Basic Information and Procedures for Noise Control” and
• measurements taken by the consultants at various construction sites. The impact of noise in the areas surrounding the site was assessed in terms of the difference between the existing measured or typical noise levels in that area and the predicted levels for the construction/dredging activities. This difference was assessed in accordance with the guidelines provided in the SANS Code of Practice 10103:2004 “The measurement and rating of environmental noise with respect to annoyance and to speech communication”, as well as the noise regulations applicable to the Western Cape (DEAT, 1998). The latter regulations define noise as ‘disturbing’ if it causes the ambient noise level to increase by 7 dBA or more over an area’s typical noise level, as designated in SANS 10103 or as otherwise designated by the local authority. As a worst-case scenario, it was assumed that equipment utilised for the quay wall extension and berth deepening and the dredging of the basin will operate simultaneously. In addition to the main construction operations, the noise from material handling at the Contractors’ Yard 31 was also taken into consideration. The assessment of impacts associated with vibrations related to blasting and other construction activities such as piling was more qualitative. Potential impacts associated with underwater blasting as a result of ground vibrations, watershock (an explosive shock wave with a steep leading edge, followed by a number of secondary pulses caused by the expansion and collapse of the explosion gas bubble), explosion gas bubble and airblast were taken into consideration in the report entitled Removal of Rock in the Port of Cape Town (Szendrei et al, 2006) which investigated the different methods of breaking rock, and determine the need for blasting. These potential impacts informed the proposed blasting regime (as described in Section 3.2.2) based on which the impacts of blasting have been assessed.
31 For the purposes of the noise impact assessment it was assumed that the Contractors Yard will be situated on the Culemborg Site.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 117 7.4.2 Noise, Shock and Vibration Baseline Information 7.4.2.1 Baseline Noise The average values of ambient noise measurements at each of 5 locations within the port, as well as Zonnebloem, as indicated in Figure 7-9, are presented in Table 7-26 below. Table 7-26: Measured ambient noise levels in and around the Port Monitoring Daytime Night-time District SANS Guideline Point dBA dBA Daytime Night-Time R1 71 67 Industrial 70 60 R2 77 75 Industrial 70 60 R3 77 71 Industrial 70 60 R4 60 52 Industrial 70 60 R5 68 55 Industrial 70 60 R6 59 57 Residential 55 45
Figure 7-9: Location of noise monitoring points and residential areas surrounding the port The potential receptors and closest residential areas to the port are Woodstock, Brooklyn, Milnerton, Zonnebloem and the V &A Waterfront hotels. Table 7-27 below shows the approximate distances from the BSD deepening operations and the Contractors’ Yard (Culemborg) to the various areas and noise receptors.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 118 Table 7-27: Distances of residential areas surrounding the port from the construction area Area Land Use Distance (m) SANS Guideline BSD Culemborg Daytime Night- Time Woodstock Commercial / Residential 1,500 700 60 50 Brooklyn Residential 2,500 2,700 55 45 Zonnebloem Residential 2,550 2,250 55 45 Milnerton Residential 4,000 4,750 55 45 Woodbridge island Residential 4,500 5,200 55 45 V & A Waterfront Commercial / Residential 1,500 3,200 60 50 To the south of the port is the commercial and residential area of Woodstock. The distances from the BSD and the Contractors’ Yard are 1.5 km and 0.7 km respectively. There are a variety of industries in the area. The noise environment is dominated by local traffic on the main road network, rail traffic as well as by industrial and commercial sources. The area can be characterised as ‘Urban district with some workshops, with business premises, and with main roads’. In accordance with SANS, the typical recommended ambient noise levels during the daytime and night-time are 60 dBA and 50 dBA respectively. The residential area of Brooklyn is situated approximately 2.5 km east of the proposed construction operations. Brooklyn is shielded from the construction operations by the Paarden Eiland industrial area. It is expected that the industrial buildings in Paarden Eiland will shield most of the noise from the dredging operations. The current noise environment in this area is dominated by the N1 highway, Koeberg Road and Marine Drive traffic. According to the procedures specified in SANS 10103, the Brooklyn area can be described as an ‘Urban’ district, with typical daytime and night- time noise levels of 55 dBA and 45 dBA respectively. The Zonnebloem residential area is in direct line of sight to the BSD area. This means that the construction operations could potentially have a negative impact on noise levels under certain meteorological conditions. The area, however, is situated quite far from the port (approximately 2.5 km) and the current noise levels in Zonnebloem are quite high, i.e. exceeding the SANS guideline for an ‘Urban’ district (see position R6 in Table 7-24). The noise levels in this area are consistently around 58 dBA throughout the day- and night-time. The main contributors to these high noise levels are local traffic, as well as traffic along the N1 and N2 highways and the existing port operations. Milnerton and Woodbridge Island residential areas are situated more than 4 km north-east of the port. The present ambient noise climate is dominated by the waves breaking on the beach, as well as traffic on Milner Drive and the local road network. Current noise levels are likely to exceed the SANS guideline for an ‘Urban’ district. The distance between the V & A Waterfront and the northern section of the BSD is approximately 1.5 km. There are a number of port buildings that could shield most of the Waterfront area from the noise emissions of the dredging operations. Noise emissions from the current port activities, the central business district and traffic on the local road network dominate the noise environment. The area can be characterised as ‘Urban district with some workshops, with business premises, and with main roads’, and is expected to have noise levels of 60 dBA and 50 dBA during day-time and night-
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 119 time respectively. This is also confirmed by the noise measurements performed at Point 4 (Figure 7- 9). From Table 7-26 it is also evident that the highest noise levels were recorded in close proximity to the current operations around the BSD, i.e. points R1 to R3. The existing noise environment in the general port area is dominated by:
• The loading and offloading operations at the Duncan and Ben Schoeman Docks;
• Traffic along Duncan Road and Marine Drive;
• Traffic along the N1 and N2 highways; and
• Commercial activities in the Central Business District (CBD).
7.4.2.2 Baseline Vibrations Unlike baseline noise levels, baseline vibration levels are almost always zero, or so small as to be insignificant, and generally immeasurable. Unlike the assessment of noise impacts, which are related to the change in noise levels, the assessment of vibrations is made on the actual predicted or measured absolute vibration values, which is the parameter that causes disturbance to humans or potential damage to buildings and marine animals. The baseline environment is therefore assumed to be pristine, i.e. completely free of shock and vibration before construction and/or blasting commences, and carrying out baseline measurements is not necessary or usual. Vibrations from natural and normal activities, including container offloading, crane and ship movements, are small compared to the energy of blasting.
7.4.3 Noise, Shock and Vibration Impact Assessment Key impacts assessed in this section are:
• Potential Increase in noise levels; and
• Potential impacts of shock and vibration resulting from blasting. These potential impacts are described and assessed in more detail in the following sub-sections (both without and with the implementation of the mitigation measures listed in Section 7.4.4).
Impact 1: Potential Increase in Noise The proposed dredging and construction activities in and around the Ben Schoeman Dock will require the use of a variety of vehicles and equipment that could result in an impact on the noise levels in the area. These would include dredge equipment and barges associated with the disposal of dredge spoil, pile driver(s), pneumatic drills, concrete batching plants, as well as large trucks transporting construction materials. The impact of noise has been assessed in terms of the difference between the ambient (existing) noise levels in the area and the predicted levels for the construction activities. While it is acknowledged that existing port activities already generate noise it should be noted that since the decibel (dB) scale used to measure noise levels is logarithmic rather than linear, two sources producing the same level of noise would not result in the amount of noise being double in the case of both producing noise simultaneously.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 120 The human ear is not equally receptive to all frequencies of sound. The A-weighting of sound levels is a method used to approximate how the human ear would perceive a sound, mostly by reducing the contribution from lower frequencies by a specified amount. The unit for the A-weighted sound levels is dBA. Table 7-28 below provides an approximation of the resulting noise levels if the difference between the levels of two sources is 1 to 10 or more decibels. For example, by removing a noise source that individually generates 6 dBA below the ambient noise level, the resulting noise level reduction would be 1 dB. Table 7-28: Adding and subtracting noise levels Quantity to be added to or Difference between the two subtracted from the higher level sound levels (dBA) (dBA) 0 3 1 2.5 2 2.1 3 1.8 4 1.5 5 1.2 6 1 7 0.8 8 0.6 9 0.5 10 or more 0 Small changes in ambient sound levels will not be able to be detected by the human ear. Most people will not notice a difference in loudness of sound levels of less than 3 dBA, which is a two- fold change in the sound energy. A 10-dBA change in sound levels would be perceived as doubling of sound loudness. Figures 7-10 and 7-11 show the predicted noise contours around the proposed work areas during daytime and night-time conditions, during the construction period, based on the noise levels associated with the equipment to be used.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 121
N
40 40 R4 45
50 45 BROOKLYN 55 R7 R2 60
50 55 70 40 R9 65 45 40 50R1 75 65 50 60 55 45
R8 R3 R5 55 60 40 40 45 50 65 55 45 dBA
50 WOODSTOCK R11 45 40 40
R6 0 1000m
Source: DDA, 2006 Figure 7-10: Daytime noise contours during construction As indicated on Figure 7-10, the 70 dBA noise contour, which represents the industrial district guideline, was found to be contained within the site’s boundaries for the BSD deepening and the Contractors’ Yard during the day. The 45 dBA zone which represents the night-time guideline noise level for residential areas, extended approximately 0.9 km from the main construction area and to the south reached the northern section of Woodstock. Areas such as Brooklyn, Zonnebloem and the Waterfront are beyond the 40 dBA zone. This means that based on the measured and adopted guideline noise levels in these areas, the difference between the construction generated noise and the existing ambient noise is greater than 9 dBA. Therefore, the noise contribution from the construction activities will be well below 1 dBA. (as indicated in Table 7-24 above) Figure 7-11 indicates the relevant noise contours for the night-time conditions. It can be seen that these conditions improve sound propagation, thus producing noise zones that extend further from the construction area. In addition, there are more stringent guidelines regarding the night-time period.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 122
N 45 40 R4 45 40
50 50 BROOKLYN 45 R7 R2 55 40 60 55 70 R9 65 R1 75 40 45 65 60 50 40 45 50 40 R8 55 R3 40 60 R5 65 40 dBA
45 50 55 50
WOODSTOCK45 R11 40
40 45
R6 0 1000m
Source: DDA, 2006 Figure 7-11: Night-time noise contours during construction The 60 dBA contour, which represents the night-time guideline for industrial districts, was found to be contained within the port while the 45 dBA zone extended half way towards (but did not reach) Brooklyn. The Contractors’ Yard under night-time conditions generated a 60 dBA zone that extended beyond its boundaries, but was, however, contained within the surrounding industrial area. The 50 dBA contour just reached the Woodstock area. Table 7-29 below indicates predicted construction noise levels at several discrete receptors, the positions of which are indicated on Figure 7-9. As can be seen, the noise levels were well below the guideline for day-time and night-time periods (i.e. lower than the guideline by approximately 6 dBA or more). The only exceptions were at the BSD quay (R1, R2 and R3) and in the Woodstock area (R11), where the noise level exceeded the night-time guideline (R1) or was marginally lower (R2, R3 and R11).
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 123 Table 7-29: Calculated noise levels at discrete receptors Receptor Location SANS District Modelled Guideline Modelled Guideline (day) dBA (night) dBA dBA dBA R1 Port Admin building Industrial 64.4 70 64.8 60 R2 BSD quay Industrial 56.1 70 59.1 60 R3 Weighing bridge Industrial 55.8 70 57.3 60 R4 NPA building area Industrial 34.3 70 38.2 60 R5 Yacht club Industrial 43.2 70 47.2 60 R6 Zonnebloem Urban 36.4 55 39.3 45 R7 Brooklyn Urban 34.4 55 38.8 45 R8 Central CBD 36.7 65 41.1 55 Waterfront Urban with 34.0 60 38.7 50 R9 business R10 Woodbridge Island Urban 23.6 55 26.7 45 Woodstock Urban with 46.7 60 49.2 50 R11 business As indicated by the noise measurements (see Table 7-26, point R2), the existing levels at the BSD quay range between 70 dBA and 77 dBA and are currently well above the SANS guideline. This means that the expected noise increase in these locations attributed to the construction operations would be approximately 1 dBA. Since the BSD quay falls within the project site, all impacts here can be regarded as occupational (a limited number of people [workers] exposed over a limited period) rather than environmental and different standards will apply. In the Woodstock area the night-time noise contribution of the construction activities is expected to be 3 dBA if the noise level in the area is around the SANS guideline of 50 dBA, and 1 dBA or less if the area’s existing noise level is higher than the guideline. The second scenario is considered to be most probable, since the existing noise environment in the area is currently impacted by heavy traffic, commercial and industrial activities. The modelling of noise associated with the proposed project thus indicates that during dredging and construction activities, the noise impact will be area specific. Neither the daytime guideline noise level of 70 dBA or the night time guideline level of 60dBA applicable to industrial districts would be exceeded outside the site boundaries. The dredging and construction activities at BSD will thus have a negligible effect on the existing noise levels in the nearby residential areas, i.e. well below 1 dBA. The community in the nearest residential area of Woodstock is expected to have no observed reaction since the noise increase will not be noticeable. The same applies to Zonnebloem and Woodbridge Island. In terms of the SANS guidelines, a change in noise levels of 3dBA or less would be only slightly noticeable, and would be considered to be a very low noise impacts, which would result in little to no community response. Due to the low noise impact that is expected to result, no essential mitigation of noise impacts is required, and an assessment of the noise impact “with mitigation” has thus not been provided. Recommendations have, however, been made in section 7.4.4 of measures that could be implemented to reduce noise levels.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 124 Table 7-30: Significance of the potential noise impacts
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very Low Definite VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential noise impacts associated with dredging and construction activities is thus rated as very low .
Impact 2: Shock and vibration as a result of blasting Shock and vibrations resulting from the blasting of rock in the harbour as well as piling could have an effect on humans, structures surrounding the area in which blasting is to take place, as well as marine animals. The impacts on marine ecology have been addressed in the integrated marine study, and found to be insignificant and are therefore not addressed further in this section of the report. Unlike most other construction related impacts, blasting is an infrequent event which affects the environment for only a very short time, usually seconds. For that reason the impact of blasting is usually low even if the instantaneous vibration level is significant either from the point of view of human reaction or building response. Vibrations from pile driving operations, which may be far longer in duration, are not significant at distances of 50m or more, even if the piles are large and impact driving methods are used. Humans are extremely sensitive to low levels of vibration and can detect levels of ground vibration of less than 0.1 mm/s, which is less than 1/100 th of the levels which could cause even minor cosmetic damage to a normal building. Complaints and annoyance regarding ground vibration are therefore much more likely to be determined by human perception than by noticing minor structural damage. However, these effects, and the startling effect of sudden impulses of both sound and vibration are often perceived as intrusion of privacy and could be a source of considerable annoyance to the local community. Both an acoustic pulse transferred to the air from the water and ground surfaces and ground vibration can give rise to secondary noise in a building, such as the rattling of windows and other loose objects which are in a state of neutral equilibrium. This is often experienced as a far more threatening occurrence than it really is. An additional complication is that a blast will generally contain frequencies below those which can be detected by the human ear i.e. below 20Hz. These low frequencies also contain sufficient energy to give rise to secondary noise, just as with ground vibration, making it characteristically difficult to differentiate between the effects and the perception of airborne sound and ground-transmitted vibration. Blasting operations are unlikely to have any damaging effect on humans, if these blasting operations are designed and carried out with due regard to good blasting practice. There is wide agreement in the industry that the Peak Particle Velocity (PPV) is the parameter which best correlates with observed damage to structures caused by vibration and is widely applied in assessments. The first observable damage to structures, the forming of hairline cracks in plaster, begins at a PPV of about 25mm/s. The US Bureau of Mines recommends twice this value, 50mm/s, as the limit for residential property. Minor structural damage can occur at values in excess of 100mm/s, and serious damage occurs at values in excess of 200mm/s, according to a range of
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 125 authors (Lear, 1992). Effects on temporary structures are likely to occur at values which are lower than for masonry structures, though the high variability in the type and construction quality of such structures renders reliable prediction of these values difficult. The maximum threshold values of PPV for different types of structures, as recommended by African Explosives Limited are presented in Table 7-29. Table 7-31: Recommended maximum threshold values of peak particle velocity for different types of structure. Recommended maximum level Blasting Situation (mm/s) Heavily reinforced concrete structures 120 Property owned by the concern performing blasting 84 operations where minor plaster cracks are acceptable Private property in reasonable repair where public concern 50 is not an important consideration Private property if public concern is important or if blasting is 10 conducted on a regular and frequent basis The PPV for a ground blast is related to the distance from the charge, the mass of the explosive, as well as two site-specific constants. The first relating to the efficiency of excitation of the ground by a given charge, and depends on local geology, explosive coupling efficiency, resonance effects, ground condition and water content; the second expresses attenuation of the PPV over distance. These relationships enable the size of the charge to be determined so that the PPV at a specified distance can be kept below a predefined limit. Typically it is recommended in the first instance that a set of test blasts should be considered before operations begin to determine the site specific constants for the site and calculate actual PPVs at sensitive buildings, so that levels can be controlled by competent blast design. The nature and magnitude of the response to vibration from underwater blasting operations will depend critically on the blasting regime chosen, the nature of the rock to be blasted, the size and depth of the charge, the type of explosive, local topography and geology, and the detonation sequence. The closest dwellings around the site are at distances of approximately 1.5 km from the nearest point of blasting and are therefore too distant to be affected in any way by the vibration from blasting operations. Neither is ground vibration from blasting operations likely to have any damaging effect on humans or buildings on the dock, if these blasting operations are designed and carried out with due regard to good blasting practice and with the desire to obtain cost-effective results in operational terms. Due to the low significance of the impacts resulting from blasting and vibrations, no essential mitigation is required, and an assessment of the impact “with mitigation” has thus not been provided. Prior notification of blasting activities at predetermined times on stated days, would however contribute significantly to the minimisation of the perceived impact of blasting on the surrounding community.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 126 Table 7-32: Significance of the potential impacts of blasting and vibrations
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short-term Very Low Definite VERY LOW -ve High mitigation 1 1 1 3 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential impacts associated with blasting and vibrations is thus rated as very low .
7.4.4 Recommended Mitigation Measures: Potential Noise and Vibration Impacts No essential mitigation measures are required for the management of noise and vibration impacts. Optional mitigation measures include: 1. Maintain construction equipment and ensure that silencer systems function efficiently at all times; 2. Position stockpiled materials so as to provide screening and reduce noise from specific construction operations beyond the site boundaries; 3. Notify occupants of surrounding areas, as well as divers of proposed blasting activities at predetermined times on stated days; 4. Carefully design the blasting regime to reduce the levels of ground borne vibration; 5. Design and carry out blasting operations with due regard to good blasting practice. This would include:
− Calculating the charge size and timing delay to keep ground vibration levels below pre- determined acceptable values;
− Correct stemming of blast holes to reduce noise and vibration generation and improve blasting efficiency; and
− Monitoring of ground vibration and human response by an independent third party entity to ensure that agreed levels are in fact acceptable to the occupants of surrounding areas and are being adhered to, and to modify the blasting design if required to reduce impacts. 6. Undertake a set of test blasts prior to the start of the main blasting operations, in order to determine the two site-specific coefficients which would allow for the calculation of the actual peak particle velocity at sensitive buildings, so that levels can be controlled by competent blast design. 7. Undertake biannual noise monitoring along the site’s boundaries during the construction period in order to ensure conformity with the regulations and indicate relevant corrective measures to be implemented. The measurements should be performed in accordance with procedures stipulated in the South African National Standard (SANS) Code of Practice: SANS 10103:2004.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 127 7.5 Potential Traffic Impacts
7.5.1 Traffic Study Introduction, Terms of Reference and Methodology This section is based on the Traffic Baseline and Impact Assessment, undertaken by HHO Africa, which is attached as Appendix E. The purpose of the study is to describe the existing traffic flows on the main routes servicing the Port of Cape Town, in particular the Marine Drive/ Paarden Eiland/ Container Road intersection and to assess the impact of the construction traffic generated by the berth deepening activities on these traffic flows. The Terms of Reference for the traffic study are listed below:
• Assess anticipated weekday peak and off peak hour construction traffic demand through consultation with berth deepening consulting engineers (and hazardous waste specialists if disposal of contaminated sediment is required) 32 ;
• Predict weekday peak and off peak hour traffic flows at the critical Marine Drive intersections in the vicinity of the container terminal for the construction phase, by superimposing the berth deepening construction traffic on the background traffic flows;
• Analyse the critical Marine Drive intersections in the vicinity of the container terminal during the weekday peak and off peak hours, for the construction phase, using capacity analysis techniques;
• Assess the operation and impact of the proposed Contractors’ Yard (Culemborg site) access on Duncan Road; and
• Conform to any relevant guidelines for specialist studies issued by the DEA&DP. The baseline study of current traffic flows was conducted using “worst case” traffic statistics from the weekday morning – AM (07h00-09h00), midday (11h00-12h00) and evening –PM (16h00- 18h00) peak times, along Marine Drive, Duncan Road and the N1 Freeway. The data for the impact assessment incorporated planning information for proposed future roads that may impact the Port, as well as data on the proposed construction activities at the Port such as access routes for construction vehicles, the quantity of materials to be delivered to the Contractors’ Yard and time frames for construction activities. For the purpose of this assessment, the performance criteria in Table 7-32 below have been used to assess the Level of Service (LOS), for signalised and unsignalised intersections respectively.
32 As there is no contaminated sediment as a result of the dredging operations which will need to be disposed of at a land-based disposal site, no consultation with hazardous waste specialists was undertaken.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 128 Table 7-33: Level of Service indicators for intersections Level of Service (LOS) Average Delay (seconds/vehicle) Signalised Unsignalised Intersections Intersections A 0 – 10 0 – 10 B 10 – 20 10 – 15 C 20 – 35 15 – 25 D 35 – 55 25 – 35 E 55 – 80 35 – 50 F >80 > 50
7.5.2 Traffic Study Baseline Information The port is currently served by a number of key roads and rail lines, as indicated on Figure 7-12.
Figure 7-12: Primary routes and rail lines serving the Port of Cape Town 7.5.2.1 Existing road based traffic The primary routes serving the port, as well as the existing traffic conditions have been described in detail in Chapter 5, and relevant baseline traffic conditions summarised below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 129 Marine Drive Peak hour flows along Marine Drive are predominantly southbound in the mornings (AM peak hour) and northbound in the afternoons (PM peak hour), although the flows in the opposite (non-peak) direction are also significant. During the weekday AM peak hour, the southbound flow on Marine Drive, north of Container Road, is approximately 2 100 vehicles per hour (veh/hr). The inability of the Marine Drive interchange to accommodate more than ± 1 850 veh/hr on the Marine Drive onramp to the City results in queue backup through the Marine Drive/ Container Road/ Paarden Eiland Road intersection and hence over utilisation of this intersection. Northbound flows on Marine Drive are somewhat lower and are unimpeded by traffic. During the midday peak hour, the northbound and southbound flows are approximately 1 250 to 1 550 veh/hr north of Container Road, and approximately 1 550 to 1 700 veh/hr south of Container Road. There is some spare capacity on Marine Drive during this peak hour, which also broadly reflects conditions between commuter peak periods (i.e. 09h00 - 16h00). However, increasing levels of congestion have lately been experienced during this period, as congestion starts to extend beyond the normal commuter peak periods. Furthermore, the Marine Drive/ Container Road/ Paarden Eiland Road intersection operates at a high LOS i.e. traffic experiences minimal delays during this peak period. During the PM peak hour, the northbound flow on Marine Drive is close to 2 500 veh/hr south of Container Road, and ± 2 750 veh/hr north of this road. These flows are approaching capacity conditions and the northbound carriageway cannot accommodate significant flow increases. It is also noted that the southbound flow is high, especially south of Container Road (2 000 veh/hr). Duncan Road Peak hour flows on Duncan Road also reflect commuter patterns related to accessing the CBD as this route is used as a “rat-run” for traffic wishing to bypass congestion at the Marine Drive interchange with the N1. Flows are at present considerably lower than in 2003, when a previous survey was done, due to the stricter controls in force at the access points to the Port. During the weekday AM peak hour, the major southbound flow on Duncan Road is approximately 400 veh/hr, whereas during the weekday PM peak hour, the major northbound flow is approximately 750 veh/hr. Weekday peak hour two-way flows on Duncan Road are less than the capacity of a two lane road of 2 000 veh/hr (two-way flow). The flows during all peak hours considered are significantly lower than capacity. Traffic conditions applicable to construction vehicles The traffic conditions which construction vehicles accessing the Contractors’ Yard will experience during a typical working day can be summarised as follows:
• During the AM peak period (06h30 – 09h00), there are high levels of congestion along Marine Drive in the southbound direction, lower levels of congestion in the northbound direction, but significant delays accessing Marine Drive via the N1 Freeway.
• During the inter-peak period (09h00 – 16h00), there are lower levels of congestion along Marine Drive in north- and southbound directions, although due to “peak extension” and general traffic growth, these levels are steadily being raised.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 130 • During the PM peak period (16h00 – 18h00), there are relatively low levels of congestion along Marine Drive in the southbound direction and high levels of congestion in the northbound direction. From the above, it is clear that the Port, and hence the access to the Contractors’ Yard will be least accessible during the weekday AM and PM peak periods and more accessible during the daytime inter-peak period.
7.5.2.2 Existing freight rail operations Current freight rail operations in and around the port are as follows:
• Along the Harbour/ Monte Vista rail line, which runs adjacent to Marine Drive and then adjacent to Duncan Road within the Port functional area and terminates at the Unity Yard. Currently, there are approximately 18 train movements along this line during the day (between 06h00 and 18h00), and 12 at night. This translates into average train headways (time intervals between successive trains) of 40 minutes during the day, and 60 minutes at night.
• Between the Paarden Eiland and Unity Yard along the rail culvert underneath the N1 Freeway. Currently there are approximately 12 train movements along this line during the day, and 8 at night. This translates into average train headways of 60 minutes during the day, and 90 minutes at night.
7.5.3 Traffic Study Impact Assessment The potential traffic impacts associated with the proposed project, as assessed in this section include the following:
• An increase in heavy vehicle traffic on the external road network as a result of the construction activities;
• An increase in traffic along Duncan Road at its intersection with the Elliot Basin access and proposed Contractors’ Yard access; and
• The potential conflict between construction related vehicles and train movements along the Harbour and Paarden Eiland rail lines. These potential impacts are described and assessed in more detail in the following sub-sections (both without and with the implementation of the mitigation measures listed in Section 7.5.4)
Impact 1: Increase in heavy vehicle traffic on the external road network It is assumed that the number of external truck movements destined for the Port would be at a peak during the construction of the temporary crane rail, which will be higher than the movements when the actual berth deepening takes place. This is due to the restricted time scale allowed for establishing the crane rail, in spite of the smaller quantities of material involved. Although the impacts of construction traffic on the external road network have been assessed separately for temporary crane rail construction and berth construction in the specialist study, a single assessment - indicating the worst case - has been provided in this report.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 131 The predicted number of external trips (i.e. making use of external roads rather than movements between the Contractors’ Yard and the construction area) by heavy construction vehicles during the relevant construction periods is presented in Table 7-34 below. Table 7-34: Predicted external hourly trips generated during construction periods Construction Period External Peak Hour Vehicle Trips Peak hour In 1 Out 1 Total 1 AM Temp Crane Rail 22 (14) 15 (12) 37 (24) Berth 16 (8) 9 (6) 25 (14) Midday Temp Crane Rail 17 (12) 17 (12) 34 (24) Berth 11 (6) 11 (6) 22 (12) PM Temp Crane Rail 15 (12) 22 (14) 37 (24) Berth 9 (6) 16 (8) 25 (14)
1 : Total (heavy) vehicle flows (veh/hour). It has been assumed that construction related vehicle movements will be the same for all three peak hours and that each such vehicle will perform one trip in and one trip out of the Port area during the peak hour. During the temporary crane rail construction period, 12 (truck) trips in and 12 trips out will be made during each peak hour. During the berth deepening construction period, 6 (truck) trips in and 6 trips out will be made during each peak hour. “Operational vehicles” used by construction site staff would total 10 peak hourly vehicles entering the port area, of which 2 are public transport vehicles (buses or trucks) conveying workers. Of these, 3 vehicles are assumed to exit the port area during the peak hour. The operational vehicle movements will be more variable, in that a greater proportion of vehicles will be arriving and leaving the Port during the AM (10 trips in; 3 trips out) and PM peak hours (3 trips in; 10 trips out) compared with the midday peak hour (5 trips in; 5 trips out). The trip distribution patterns to and from the Contractors’ Yard assume the predominant movement to be along the N1, via Marine Drive Interchange and along Marine Drive (80%), with the remainder from the north (20%), also along Marine Drive. All external construction related traffic is therefore routed via the Marine Drive/ Container Road/ Paarden Eiland Road intersection, along Container Road and then Duncan Road towards the Contractors yard. It is assumed that no construction related traffic would access the Contractors’ Yard via the southern section of Duncan Road. This is considered a reasonable assumption since it is very unlikely that construction related traffic will be routed through Cape Town CBD. It has recently been indicated by City of Cape Town officials that some road proposals identified as part of the N1 Corridor upgrading project, may be implemented as part of a package of infrastructure projects in preparation for World Cup 2010. This will necessitate the Contractors’ Yard being relocated to another site within the port area. This relocation will not, however, have any consequences for the impact of the berth deepening project on the external road network, since the routing of all construction traffic via Marine Drive and its intersection with Container Road is independent of internal routing and circulation arrangements.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 132 The impact of traffic generated by the berth deepening construction project, superimposed on existing commuter traffic, has been assessed by analysing the performance in terms of LOS of the following two intersections in the vicinity of the container terminal:
• Marine Drive/Paarden Eiland/Container Road Signalised Intersection; and
• Interchange Ramp from N1 to Marine Drive Unsignalised Intersection Marine Drive/Paarden Eiland/Container Road Intersection At present, this intersection operates at reasonable levels of service (LOS C) during both the weekday AM and PM peak hours, and at a high level of service (LOS B) during the midday peak hour. However, the analysis does not truly reflect the operation of this intersection during the AM peak hour due to backup from the city-bound N1 onramp at the Marine Drive interchange. During the PM peak hour, the effective metering of traffic from the N1 due to congestion on the N1, allows it to function at the indicated level of service. For the construction scenario, the performance of the intersection will deteriorate only marginally during all peak hours considered. The levels of service will not change and the effective impact on the intersection during both the crane rail and berth deepening construction periods will be negligible. Marine Drive/ Northbound Ramp Intersection At present, the critical northbound through-movement at this intersection operates at a high level of service (LOS A) during the weekday AM peak hour, at an acceptable level of service (LOS D) during the midday peak hour, and at a very low level of service (LOS F) during the PM peak hour. For the construction scenario, the northbound through movement at the intersection will continue to operate at similar levels of service to the current situation. It should however be noted that delays experienced under congested conditions increase exponentially as demand increases. The increased heavy vehicle traffic flows in and out of the Port will thus result in marginally higher levels of utilization of intersections and routes in the vicinity of the site (notably along Marine Drive), which are currently unable to absorb traffic growth during peak periods. Port and metropolitan traffic will experience some increased traffic delay during commuter peak periods. Although traffic associated with the temporary rail construction is expected to be higher than for the berth construction, the increase would still be fairly minor and would be for only a short period of time. In the case of the berth construction, the increase in traffic would occur for a longer period of time. The impact of increased traffic on the external road system can be mitigated to a degree by scheduling the bulk arrivals and departures of trucks conveying construction materials to outside peak commuter periods, thereby facilitating movement of construction vehicles to and from the Port area.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 133 Table 7-35: Significance of potential increase in heavy vehicle traffic on the external road network as a result of temporary crane rail and berth construction
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Regional Low Medium- Low Definite LOW – ve High mitigation term 2 1 2 5 With Regional Low Medium- Low mitigation term Definite LOW – ve High 2 1 2 5 The significance of the potential increase in heavy traffic on the external road network is thus rated as low as a result of construction activities.
Impact 2: Increase in traffic at Duncan Road/ Elliot Basin Access/ proposed Contractors’ Yard access Internal traffic movements comprising mostly heavy vehicles will take place as follows, as indicated on Figure 7-12:
• During the construction of the temporary crane rail and then the deepening of Berth 601, all related internal movements will take place between the Contractors’ Yard via the culvert link beneath the N1 freeway and the 4th leg to the Elliot Basin intersection, across Duncan Road towards the Ben Schoeman Dock.
• During the deepening of Berths 602 to 604, traffic will have to turn right from the Contractors’ Yard into Duncan Road, then proceed up to Container Road, then turn left towards the container terminal buildings, routed along the perimeter gravel road alongside the sea edge. At present, the unsignalised three-way stop controlled intersection (of Duncan Road and the Elliot Basin Access) operates at high levels of service (LOS B) during the weekday AM and inter-peak hours, and at reasonable levels of service (LOS C) during the weekday PM peak hour. For the construction scenario, a fourth leg will be added to this intersection, which will be four-way stop controlled. The existing traffic that utilises Elliot Road will be rerouted to the west to make use of the alternative access to the yacht club (Alkmaar access). In the future, this intersection will continue to operate at high levels of service (LOS B) during the weekday AM and inter-peak hours, and at reasonable levels of service (LOS C) during the weekday PM peak hour, with overall intersection delay virtually unchanged. The movement of berth deepening related construction traffic along the proposed link to the Contractors’ Yard will need to be regulated with respect to the train movements along the Harbour and Paarden Eiland rail lines. This will most readily be achieved by the deployment of a traffic marshal, who will need to be in communication with train operators at the central traffic control centre with regard to train movements. It should be noted that precedent for at grade (level) crossing of the harbour rail lines is well established. The existing major access to the Port at Oswald Pirow operates on the same principle and accommodates significantly higher traffic flows. The increase in traffic along Duncan Road and its intersection with the access points to the Elliot Basin and proposed Contractors Access Yard would lead to only a marginal increase in travel time delay for vehicles traveling along this route. Due to the very low significance of this impact it is not
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 134 considered necessary to implement mitigation measures and an assessment “with mitigation” has not been provided in the table below. Table 7-36: Significance of potential increase in heavy vehicle traffic on the internal road network
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Medium- Very Low Definite VERY LOW – ve High mitigation term 1 1 2 4 With mitigation n/a n/a n/a n/a n/a n/a n/a n/a
The significance of the potential increase in heavy traffic on the internal road network is thus rated as very low .
Impact 3: Potential conflict between construction and train movements The Contractors’ Yard, situated on the Culemborg site, will be accessed via the culvert beneath the N1 Freeway. This requires that a temporary gravel road be constructed along the western barrel of the culvert and pre-cast concrete slabs be placed across the railway lines on exit from the culvert. This will not impact on freight rail operations significantly, since a rail line is only operational along the eastern barrel of the rail culvert. Traffic movements crossing rail lines will need to be regulated to take account of freight train movements. A traffic marshal in communication with train operators at the central train control centre will ensure this regulation. A four-way stop controlled intersection is proposed at the intersection of the Contractors’ Yard access road and Duncan Road. The alignment of the proposed Contractors’ Yard access road across the Harbour and Paarden Eiland rail lines, creates a potential conflict point between construction-related vehicles and trains. The nature of the impact is such that a traffic marshal will need to be deployed at this point, who will need to be in communication with train and signal operators at the central traffic control centre. It is not considered necessary to introduce additional mitigation measures to address the above impact, given its very low significance, the deployment of a traffic marshal is considered an essential mitigation measure, although this would not result in a decrease in the impact rating. Table 7-37: Significance of potential conflict between construction traffic and train movements
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Medium- Very Low Definite VERY LOW – ve High mitigation term 1 1 2 4 With n/a n/a n/a n/a n/a n/a n/a n/a mitigation The significance of the potential conflict between construction traffic and train movements is thus rated as very low .
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 135
7.5.4 Recommended Mitigation Measures: Potential Traffic Impacts Essential mitigation measures include: 1. Schedule the bulk of arrivals and departures of truck conveying construction material during the commuter inter-peak periods (between 09h00 and 16h00 and 18h00 – 06h30); 2. Implement a stop control at the Contractors’ Yard access road approach to Duncan Road; and 3. Deploy a traffic marshal at the crossing of the access road from the Contractors yard with the Harbour and Paarden Eiland rail lines. The traffic marshal is to maintain communication with the train and signal operators at the central traffic control centre.
7.6 Potential Visual Impacts
7.6.1 Visual Study Introduction, Terms of Reference and Methodology This section is based on the Visual Baseline and Impact Assessment, undertaken by SRK Consulting, which is attached as Appendix F. The specialist visual assessment seeks to give insight into the visual character and quality of the area, its visual absorption capacity and the potential significance of the visual impacts created by the proposed project in order to evaluate these impacts from a visual perspective. The Terms of Reference for the visual specialist study were as follows:
• Provide an overview of existing visual conditions in the affected environment;
• Identify potentially affected parties and viewpoints;
• Identify the sources of the visual impacts, (including dredging activities);
• Where required, identify the need for mitigation and suggest methods to achieve this; and
• Conform to any relevant guidelines for specialist studies issued by the DEA&DP. The magnitude or intensity of the visual impacts for the activities at the port and the alternative dredge disposal sites was determined through analysis and synthesis of the following factors:
• Visibility and viewing distance;
• Visual absorption capacity;
• Landscape / townscape integrity; and
• Sensitivity of viewers. Assessment of the visual impacts associated with the dredging activities has also been informed by the Integrated Marine Impact Assessment undertaken by the CSIR, which included modelling of the distribution of sediments/plumes in the ocean.
7.6.2 Visual Study Baseline Information The Port of Cape Town has a unique sense of place or strongly defined visual character. This is created by the activities of the working harbour, with the associated visual elements such as the stacks of containers, gantry cranes and shipping vessels. This is complemented by the backdrop of the surrounding visually appealing mountains and sea. Overall the sense of place is one of a working
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 136 harbour in a visually appealing context, which creates a visual character that is industrial but congruent with its surrounds. The Visual Absorption Capacity (VAC) is the potential of an area to conceal a proposed development, or absorb visual impacts. The VAC of the BSD is considered to be high due to the existing highly urbanised (industrial) nature of the site and the screening provided by the buildings and structures in the harbour and surrounds (particularly the CBD). Additionally, the background conditions of the sea in the bay absorb much of the visual impact generated by the sediment plumes. Sediments entering the sea from river estuaries naturally result in visible plumes, and there is naturally occurring suspended sediment concentration in the surf-zone. These factors, together with reflected light and the colour of the sea, contribute to the VAC of the sea Cape Town has a number of points that offer scenic views of the city and surrounding areas, including the Port of Cape Town, several multi-storey hotels located within the Cape Town CBD and in close vicinity to the V&A Waterfront, elevated natural features including Table Mountain and Signal Hill, which are popular tourist attractions, transport routes on the slopes of Table Mountain (e.g. N2 and De Waal Drive) as well as residential areas and recreational areas along the eastern shoreline of Table Bay. There is generally a very low-to-low visibility from the affected viewpoints due to typically low angles from view points relative to sea level or long distances to the affected area.
7.6.3 Visual Study Impact Assessment Potential visual impacts associated with the proposed deepening of the Ben Schoeman Dock and upgrade to the berths include impacts as a result of:
• Dredging and disposal and associated sediment plumes;
• Berth deck construction activities; and
• New crane installations. Potential visual impacts are described and assessed in more detail in the following sub-sections, both without and with the implementation of the mitigation measures listed in Section 7.6.4.
Impact 1: Visual impacts of dredging and disposal and associated sediment plumes The visual impact of the sediment plumes is caused by suspension of fine sediment in surface water during dredging and the disposal of dredge spoil. The visibility of the suspended sediment, in the form of a plume, depends on a number of factors such as the:
• Colour of the suspended sediment;
• Concentration of the suspended sediment;
• Background concentration of sediment in the water, which may vary seasonally;
• The state of the sea;
• Angle of the sun (light conditions); and
• Elevation of the viewer.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 137 Currently, natural sediment plumes are regularly experienced in Table Bay. These plumes result from the river inflows from the Salt and Diep Rivers and from sediment entrained in the surfzone. They vary in colour and the darker sediments entering the Bay from the Salt River closer to the Port are significantly less visible than the lighter sediments entering the Bay from the Diep River further north. It is anticipated that the sediments dredged from the BSD will be dark-coloured mud. The plumes resulting during dredging and disposal of dredge spoil will therefore consist of dark sediment against the background of the darker blue water. Sediment plumes become visible at suspended sediment concentrations of between 9 and 13 mg/l, with a significantly more visible plume occurring at a concentration of 23 mg/l. Based on background conditions for Table Bay it is assumed that sediment concentrations are likely to become visible at about 10 mg/l. (CSIR, 2006a) The plumes in the BSD will be temporary, generated only during dredging activities. Sediment plumes as a result of dredged material being flushed out of the port and accumulating in the quieter regions of the bay are only likely to be visible for a total of 2 to 5 days out of a 90 day period and are likely to occur close to the shore (near Mouille Point). The dark plumes in the BSD will have low visibility against the dark blue background of the water. Plumes created at the disposal sites will only occur when dredged material is dumped. The plumes will only be visible for a short duration and are expected to be visible for a cumulative total of 2 to 5 days in a 90 day period. Various scenarios for disposal are being considered (based on various dredge options available) and the scenarios with a greater number of dumps per day will therefore have a marginally greater visual impact. The impact, although negligible, is greatest for the “combination cutter suction dredger and backhoe dredger” operation due to the greater number of hopper barge dumps assumed per day for these scenarios. The creation of sediment plumes is predicted to be greatest in winter, however the spatial extent of plumes in winter is likely to be masked by the generally higher turbidity expected during this season. The plumes are only likely to be visible from certain elevated positions such as Table Mountain, Signal Hill and certain view points from the N2 and De Waal Drive. Even then, the visibility of the plumes is expected to be limited by the following factors:
• The relatively low angle of the viewer relative to the water surface from most of these view points (the closer the viewer is to sea level the less visible the plume will be);
• The relatively short period of time most viewers are expected to spend at any given viewpoint;
• The relatively short period of time the plumes are expected to be visible;
• The distance of most view points from the affected areas (2.5 km +); and
• The occasional natural occurrence of sediment plumes along the Table Bay coastline, indicating that the dredging plume would not be a highly unusual phenomenon for the area. As such, the significance of the visual impact of the dredging and dumping activities is considered to be very low and no essential mitigation of this impact is required. Assessment of this impact “with mitigation” is thus not provided in the table below.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 138 Table 7-38: Significance of the potential visual impact of dredge plume
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short term Very Low Probable Very Low -ve Medium- mitigation 1 1 1 3 High With mitigation n/a n/a n/a n/a n/a n/a n/a n/a
The significance of the potential visual impacts of sediment plumes resulting from dredging and the disposal of dredge spoil is thus rated as very low .
Impact 2: Visual impacts of berth deck construction activities The extension of the berth deck involves the dredging of a scour protection trench, the driving of piles into the sea bed to support the deck extension and the construction of a concrete deck extension, casting the concrete in situ or using pre-cast concrete. Visual impacts at the BSD will be mainly related to these construction activities, as well as machinery and material moving on the site. In addition, storage of construction materials, concrete batching and welding activities are proposed to take place on the 1.8 ha Contractors’ Yard south of the BSD. This site is surrounded by industrial infrastructure of the BSD and the Woodstock industrial area and not easily accessible or visible to the public. The impact on the visibility of the construction areas is expected to be limited by:
• The current visual context and industrial nature of the area, which will visually absorb additional construction machinery and activities at the BSD and the Contractors’ Yard;
• The fact that vessels of different sizes are already using the BSD, so that additional dredging- related vessels would not be highly noticeable;
• The relatively short period of time most viewers are expected to spend at any given viewpoint;
• The distance of most tourist view points from the BSD (2.5 km +); and
• The temporary nature of the construction activities. Some mitigation measures to reduce the negative visual impacts of construction are suggested in Section 7.6.4. However these are not expected to significantly reduce the visual impact and the very low rating therefore remains the same. Table 7-39: Significance of the potential visual impact of construction activities
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Short term Very Low Probable Very Low -ve High mitigation 1 1 1 3 With Local Low Short term Very Low Probable Very Low -ve High mitigation 1 1 1 3 The significance of the potential visual impact of the berth construction activities, assuming the implementation of mitigation measures, is thus rated as very low .
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Impact 3: Visual impact of new crane installations The BSD currently accommodates four Demag and two Noell ship to shore cranes, which are located on rails running parallel to the edge of berths 601 – 604. The cranes are mobile and can be moved on the rails along the berths as required to load and load containers onto and from vessels moored along the berths. Initially, the four Demag cranes will be replaced by six new cranes, resulting in a total of eight working cranes. The intention is to eventually replace these existing cranes with up to a total of 12 new cranes , dependent on demand. The approximate dimensions of the existing and proposed cranes are indicated in Table 7-39. Table 7-40: Approximate dimensions of cranes Crane Approximate Height Approximate (with jib in upright Length position) Demag 75 m 90 m Noell 92 m 105 m Proposed new cranes 99 m 105 m Source: Transnet The main visual impact from the new cranes would thus result from their greater height (7 m higher than Noell cranes and 24 m higher than Demag cranes) and potentially from the increased number of cranes. They are therefore likely to have increased visibility from a number of viewpoints, including certain points along De Waal Drive and the N2, from Table Mountain and some of the surrounding hotels. The visual impact of the newly installed cranes is however expected to be limited due to:
• The existing industrial nature of the site, which includes crane installations both at the BSD and Duncan Dock, which is located much closer to viewers, so that the installation of new cranes - even though higher - at the BSD will not significantly alter the existing visual environment;
• The distance of most tourist view points from the BSD (2.5 km +); and
• The relatively short period of time most viewers are expected to spend at any given viewpoint. Some mitigation measures to reduce the negative impacts of the new crane installations are suggested in Section 7.6.4. However these are not expected to significantly reduce the visual impact and the rating therefore remains the same. Table 7-41: Significance of the potential visual impact from new cranes
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local Low Long term Low Probable Low -ve High mitigation 1 1 3 5 With Local Low Long term Low Probable Low -ve High mitigation 1 1 3 5 The significance of the potential visual impact of the new cranes, assuming the implementation of mitigation measures, is thus rated as low .
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 140 7.6.4 Recommended Mitigation Measures: Potential Visual Impacts No Essential mitigation measures are required to reduce the visual impacts associated with the project. Optional mitigation measures include: 1. Consider the visual impacts of sediment plumes in selection of the most suitable dredge method. 2. Limit the area used for construction activities including the associated storage of waste, materials and equipment; 3. Ensure that rubble and waste material are removed regularly from the site; 4. Store construction equipment and material in an orderly manner on a designated site; 5. Unless considered a safety risk, paint cranes a colour that will be least visible against the skyline (grey/blue); and 6. Monitor and react to complaints about plumes generated by project activities. .
7.7 Potential Maritime Archaeological Impacts
7.7.1 Maritime Archaeology Study Introduction, Terms of Reference and Methodology This section is based on the Maritime Archaeology Baseline and Impact Assessment, undertaken by Bruno Werz, which is attached as Appendix G. The purpose of the study was to identify the underwater heritage resources that may be present in the study area, and to assess the impact of the proposed project on these resources. The Terms of Reference for the assessment were as follows:
• Review existing studies at the Port of Cape Town, e.g. the Strategic Environmental Assessment of the Port of Cape Town and the Container Terminal Expansion, to identify maritime archaeological features in the vicinity of the proposed activities;
• Review legal requirements in terms of heritage legislation relevant to this EIA;
• Identify potential maritime archaeological issues related to the proposed project;
• Consult with the South African Heritage Resources Agency (SAHRA) to confirm the approach and findings of the review as well as compliance with relevant heritage legislation;
• Where required, identify the need for mitigation and suggest methods to achieve this;
• Devise a practical monitoring programme that will, firstly, allow real time control of project activities to reduce environmental risks and, secondly, facilitate a qualitative determination of actual versus predicted project impacts; and
• Conform to any relevant guidelines for specialist studies issued by the DEA&DP. Determination of the potential existence of material of archeological, cultural or historical value within the areas to be affected by the project included a desk top analysis of relevant literature, databases and archival documents; the interpretation of cartographic material; as well as interviews with oceanographers, geologists and archaeologists from the University of Cape Town and the South
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 141 African Museum regarding wind and current patterns in the bay, beach morphology, prehistoric material onshore and historical sites within the harbour area.
7.7.2 Maritime Archaeology Study Baseline Information Details of the maritime archaeological material previously encountered in Table Bay has been described in detail in Section 5.2.4. Available information does not allow for the accurate prediction of the exact location, nature, current state and extent of the underwater cultural resource that may be encountered during the proposed works, and the assessment undertaken and proposed mitigation measures have been based on the potential for material to be uncovered, based on what is known to exist in the broader region. Due to previous dredging operations in the Ben Schoeman Dock, it is likely that much of the material that may have occurred in this area has been disturbed and removed. The possibility (although small) however exists that some such material may still exist in some areas.
7.7.3 Maritime Archaeology Study Impact Assessment In the case of material of archaeological value existing in the Ben Schoeman Dock, the potential impact of the proposed project would be the disturbance of such archaeological sites and the resulting damage to and dispersal of cultural material, mainly as a result of blasting and dredging activities. The potential impact is described and assessed in more detail in the following table, both without and with the implementation of the mitigation measures listed in Section 7.7.4
Impact 1: Impact on Marine Archaeology The proposed deepening of the Ben Schoeman Dock includes dredging of a layer of material approximately 4.8m thick from the area of Berth 600, 2.7m near Berth 601 and 1.5m from the western section (berths 602-604). An estimated volume of 86,956m³ of hard rock is present in the area, which will require blasting making use of multiple small charges. Although blasting may damage archaeological material should it occur in the area, the impact will be less than in the case of indiscriminate blasting. Various dredging options are being considered, although the nature of the dredge equipment that will be used cannot yet be finalised and the assessment of the impacts of dredging on archaeological material that may occur in the area has thus assumed a worst case scenario. From an archaeological point of view, a dredger with relatively limited capacity would reduce the damage that may be caused, especially to larger items, such as parts of a shipwreck’s hull. A dredge operation which would allow dredged material to be expelled onto an exposed surface, would allow for the option of visually monitoring at least part of the removed deposits. This visual control, combined with the option to temporarily stop dredging activities to recover cultural material, represents the most important mitigating factors from an archaeological perspective for this specific project. The use of a TSHD does not seem to offer such opportunity. In the case of the use of a backhoe dredger, this will facilitate temporarily movement to another area should archaeological material be
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 142 found. In this way, dredging can continue while there is an option to survey specific areas elsewhere for more archaeological material. In terms of the disposal of dredged material, the use of the shallower of the two potential sites (Site 2) would be considered more favourable than the deeper site (Site 1) from an archaeological perspective (not marine ecology perspective). This would allow a limited chance that objects or materials of archaeological value to still be recovered following disposal. This would be seriously hampered in the case of disposal at Site 1, due to the need for specialized diving equipment in order to recover such materials. The potential impact on marine cultural resources is considered to be of high intensity, due to the uncertainty of the existence of material that may exist in the basin (and thus application of the precautionary principle). In the case of such material being present, disturbance as a result of blasting and dredging activities is inevitable. As this material will be permanently lost if suitable measures are not taken to recover and record the position and existence of the find, the rating of this impact without mitigation is considered medium. The extent of the impact which could occur relates specifically to the physical remains of the underwater cultural heritage that may be present in the basin. The extent is thus considered local, although this does not take into consideration the non-tangible values that can be attributed to this heritage. If, for example, parts of a 19 th century British shipwreck are uncovered, its attributed value to the history and culture of South Africa and Britain is not taken into consideration, but merely the fact that it is located in the BSB. Making allowance for intervention and monitoring by a suitably qualified maritime archaeologist during dredging activities would allow for the significance of this impact to be reduced, as any material which may be encountered could be recorded and recovered where considered necessary. Table 7-42: Significance of potential impact on marine archaeology
Extent Intensity Duration Consequence Probability Significance Status Confidence Without Local High Long-term High Possible MEDIUM – ve High?? mitigation 1 3 3 7 With Local Low Long-term Low Possible LOW – ve High mitigation 1 1 3 5 The significance of the potential impact on archaeological material that may be present in the Ben Schoeman Dock, assuming the implementation of mitigation measures, is thus rated as low . Note: Although the specialist has rated the probability of this impact occurring (without mitigation) as probable , resulting in a high significance rating, based on the opinion of the EIA consultant, with more holistic view of the overall impacts, this probability rating has been reduced to possible , resulting in a medium significance (without mitigation). This is based on the fact that the area to be dredged has been extensively dredged in the past, and much of the cultural resource which may have occurred is likely to have been disturbed in the past.
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7.7.4 Mitigation measures: Maritime Archaeological Impact Essential mitigation measures include: 1. Where applicable, take the recommendations of the Maritime Archaeologist into account when planning and conducting blasting and dredge operations to minimize impacts on the potential cultural resource; 2. Inform both NPA and SAHRA of the exact location and extent of the dredge disposal site; 3. Ensure that all contractors and subcontractors are made aware of the potential existence of underwater heritage resources, and instructed on the correct procedure for preserving the integrity thereof. Also instruct sub-contractors to monitor dredging activities (through visual inspection of at least part of the dredge material brought to the surface before being deposited at the disposal site, where possible) for any cultural material that may be uncovered. In the case of material being uncovered, a qualified archaeologist is to be notified immediately and the material secured and kept for inspection; 4. Ensure that monitoring is particularly vigilant during dredging of the area from Berth 603 westwards; 5. Formally inform SAHRA in writing of the planned development; 6. Retain a suitably qualified archaeologist as a consultant for the duration of the dredging operations to provide advice to the Contractor as and when required. This person may have to: liaise with SAHRA and the client / dredger operators; pay ad hoc site visits to monitor blasting and dredging activities; secure the necessary licences and permits from the Controller of Customs and Excise and the SAHRA; and render assistance should any cultural material be dredged up; 7. Provide assistance should the maritime archaeologist deem it necessary to undertake an underwater survey and/or remove material. This may include support from NPA divers and others; 8. Make provisions for essential mitigating activities related to underwater cultural material that may be recovered. This would include:
− making funds available for monitoring activities to be undertaken by the project’s maritime archaeologist if required;
− funding for potential limited underwater fieldwork if required;
− funding for the basic preservation and documentation of dredged up material if required; and
− allocation of a suitable area where recovered material may be temporarily stored and treated if required; and 9. Allow for any valuable material recovered during dredging to be adequately stored and preserved. Excavation and recovery can only be done after a licence from the Department of Customs and Excise has been issued and a permit from the SAHRA has been obtained.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 144 Optional mitigation measures are: 1. Where practicable and cost effective, preferably make use of a backhoe dredger, which allows for visual monitoring of the dredge spoil before it is removed. This is especially the case in the archaeologically sensitive area from berth 603 towards the entrance channel; and 2. Preferably dispose of dredge spoil in an area that will allow future recovery of heritage resources. It should be noted that either of the proposed dredge disposal sites would allow for this, although the associated costs would be higher for a deeper site.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 145 8 Evaluation and Recommendations This chapter provides an integrated evaluation of the potential impact of the proposed deepening of the Ben Schoeman dock and associated upgrades to Berths 601 – 604. The principal findings of the specialist studies and Environmental Impact Assessment are presented in this chapter, followed by a discussion of the key factors which DEAT will have to consider in order to take a decision leading to a sustainable outcome. Mitigation measures, which this assessment assumes will be implemented, have been copied for ease of reference directly from Chapter 7.
8.1 Evaluation The evaluation is undertaken in the context of:
• the information provided to date;
• the assumptions made for this Draft EIR;
• the recommended essential mitigation measures which it is assumed will be effectively implemented;
• the assessments provided by the specialists; and
• the practicality of the recommendations for mitigation.
• This evaluation aims to provide answers to a series of key questions posed as objectives at the outset of this report, which are repeated here:
• Identify and assess significant impacts associated with the proposed deepening of Ben Schoeman Dock and associated upgrades to Berths 601, 602, 603 and 604;
• Indicate whether the two possible sites at depths of ~40 m and ~70 m respectively, are environmentally acceptable locations for the disposal of dredge spoil;
• Formulate mitigation measures to minimise impacts and enhance benefits; and
• Produce a Final Environmental Impact Report (EIR) which will help DEAT to decide whether (and under what conditions) to authorise the proposed berth deepening project. The evaluation and the basis for the subsequent discussion are represented concisely in Table 8-1 below. This table indicates the significance of each impact, associated with the overall project, in the case of disposal of dredge spoil at each of the two dredge spoil disposal sites identified as alternatives. Where impacts are not related with dredge spoil disposal, the same impact rating has been provided in the case of each of the two alternatives. Impact ratings provided in the table assume the implementation of all essential mitigation measures, but not of optional mitigation measures.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 146 Table 8-1: Impact rating summary for the proposed upgrades to berths and associated deepening of Ben Schoeman Dock Impact Significance (with Potential Impact Status Key Mitigation Measures / Recommendations mitigation) Marine Impacts Impacts of dredging activities on the harbour environment Removal of biological communities in dredge areas -ve Very Low No mitigation required Impact of sediment plumes in dredge area on organisms -ve Very Low No mitigation required in the harbour Impacts of settlement of suspended sediment and -ve Very Low No mitigation required changes in sediment characteristics on sediment biota Apply both the NPA Ballast Water Management Plan and the relevant ballast water management protocols stipulated in the IMO International Importation of alien species into dredge area by dredgers -ve Low Convention for the Control and Management of Ship’s Ballast Water and Sediments and verify implementation. Impacts on dredge spoil disposal sites and surrounds Dredge disposal Dredge disposal
site 1 site 2 Effects of sediment deposition on benthic macrofauna -ve Very Low Medium Ensure that sediments are discharged in thin layers where possible. Alteration of benthic biological communities through -ve Very Low Low No feasible mitigation available toxins in dredge spoil Effects of turbidity from dredge spoil disposal on habitats -ve Insignificant Medium No feasible mitigation available surrounding disposal site Effects of sediment plumes on water quality and biota in -ve Insignificant Low No feasible mitigation available Table Mountain National Park MPA Apply both the NPA Ballast Water Management Plan and the relevant ballast water management protocols stipulated in the IMO International Introduction of alien species to dredge disposal sites -ve Medium Medium Convention for the Control and Management of Ship’s Ballast Water and Sediments and verify implementation. Effects of turbidity resulting from dredge spoil disposal on Ensure there is no chronic build up of turbidity in the area of the dredge endangered coastal seabirds (specifically the African -ve Low Low disposal site through allowing sufficient time for turbidity to subside Penguin) between dump events. Potential erosion of the shoreline as a result of disposal of -ve No impact Insignificant No mitigation required dredge material Impacts on existing uses in Table Bay Deposition of sediments in existing dredge areas and/or -ve Low No feasible mitigation available navigation channels
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Impact Significance (with Potential Impact Status Key Mitigation Measures / Recommendations mitigation) Interference with existing shipping operations -ve Very Low No feasible mitigation available
Noise, Shock and Vibration Impacts Potential increase in noise levels -ve Very Low Implement normal noise control measures during construction. Lure seabirds and marine mammals out of the harbour prior to blasting. Provide prior notification of blasting to people in areas surrounding the Impacts of shock and vibration from blasting and -ve Very Low site. construction Design and carry out blasting operations with due regard to good blasting practice. Traffic Impacts Where possible schedule bulk arrivals and departures of trucks carrying Increase in heavy vehicle traffic on external road network -ve Low construction materials outside peak commuter periods. Increase in heavy vehicle traffic on internal road network -ve Very Low No mitigation required Deploy a traffic marshal at crossing of contractor’s yard access road with Potential conflict between construction and train -ve Very Low harbour and Paarden Eiland rail lines to communicate with train and movements signal operators at the central traffic control centre. Visual Impacts Visual impacts of dredging and sediment plumes -ve Very Low No mitigation required Implement good housekeeping during construction to reduce visual Visual impacts of berth deck construction activities -ve Very Low impacts of construction activities and at contractor’s yard. Consider painting cranes a colour that will be least visible against the Visual impacts of new crane installations -ve Low skyline (blue/grey) taking due consideration of safety implications. Impacts on Marine Archaeology Ensure all archaeological material encountered can be recorded, recovered and stored. Disturbance of archaeological material that may occur in Appoint a maritime archaeologist to monitor and advise on -ve Low Ben Schoeman Dock archaeological finds. Obtain necessary permits and licenses prior to removal of archaeological material.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 148 Relevant observations with regard to the overall impact ratings , assuming mitigation measures are effectively implemented, are:
• The predicted very low impacts of dredging activities on the biological communities within the harbour , due to the previous disturbance in this area and generally low levels of species diversity. The impact of the introduction of alien species by ballast water in dredge equipment is rated as low , provided that ballast water is suitably managed;
• The predicted very low impacts of the disposal of dredge spoil on the biological communities and habitats at Site 1 due to the limited dispersion of sediments from this deeper site as well as the large amount of similar habitat in Table Bay. The impacts of dredge spoil disposal at Site 2 will have low to medium impacts due to dispersion of sediments over a larger area (including into the TMNP Marine Protected Area) due to increased wave effects at this shallower site, as well as the fact that the extent of similar habitat in Table Bay may be limited. At both sites, the introduction of alien species as a result of ballast water from dredgers and hopper barges would have a medium impact due to the fact that in the case of this occurring, indigenous species would be obliterated by natural processes of competition, predation etc and impacts may thus be long term;
• The predicted insignificant impacts of the disposal of dredge spoil at either of the two potential dredge disposal sites on the stability of the shoreline in Table Bay , due to the distance of both of these sites from the sandy beaches which would potentially be impacted;
• The predicted low to very low impacts on existing activities in the area , including existing shipping activities, maintenance of navigation channels as well as the intake of water of suitable quality to feed the Two Oceans Aquarium (assuming water quality is suitably monitored and mitigated) ;
• The predicted very low noise and vibration impacts associated with blasting, dredging and construction activities based on levels of noise generated and existing relatively high ambient noise levels which serve to mask predicted noise-generating activities;
• The predicted low to very low impacts of traffic related with construction activities on the internal and external road networks primarily due to the low volumes of traffic generated by the project as well as existing high background traffic levels;
• The predicted very low visual impact of the dredging and construction activities, and low visual impact of the new cranes, due to the fact that these impacts will occur in the context of a working harbour and the high Visual Absorption Capacity of the surrounding area ;
• The predicted low impact on archaeological material that may occur in the basin, due to likely disturbance by previous dredging activities, provided that allowance is made for monitoring and recording of any material that is found.
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8.2 Environmental Suitability of Alternative Dredge Disposal Sites Salient observations related to environmental suitability of each of the two alternative dredge spoil disposal sites are:
• The following impacts are not related to the choice of disposal site:
− Impacts on the harbour environment as a result of dredging activities;
− Noise and vibration impacts associated with blasting and construction activities;
− Visual impacts associated with construction activities; and
− Traffic Impacts;
• Both sites are considered environmentally suitable for the disposal of dredge spoil from a marine ecology point of view, provided mitigation measures are effectively implemented. Site 1 is, however, the preferred site from a marine ecology perspective as the majority of impacts assessed are higher at Site 2.
• Both sites are considered environmentally suitable for the disposal of dredge spoil from a shoreline stability point of view. Although a minor impact (considered insignificant) may occur as a result of disposal at Site 2, no impact on shoreline stability is anticipated in the case of disposal at Site 1. Site 1 is thus marginally preferred from a shoreline stability perspective ;
• Both sites are considered environmentally suitable for the disposal of dredge spoil. In terms of deposition of sediment in navigation channels, this impact - despite being negligible - will be greater at Site 2 due to its proximity to the port entrance and greater resuspension of dredge spoil from the shallower site. In terms of shipping traffic, Site 2 would be closer to the more congested area near the entrance to the port, and Site 1 is thus the marginally preferred site in terms of impacts on existing uses in Table Bay ;
• Both sites are considered environmentally suitable for the disposal of dredge spoil from a visual impact perspective. Although the surface sediment plume associated with disposal at Site 2 is larger and slightly more persistent in the worst case scenario, due to the distance from the shore and the temporary nature of the impact, the impact is considered equal at either of the sites, and both sites are equally suitable, i.e. neither is preferred from a visual perspective ; and
• Both sites are considered environmentally suitable for the disposal of dredge spoil from a maritime archaeology point of view. Although the potential disturbance of archaeological material is linked to dredging activities, disposal of dredge spoil at Site 2, the shallower of the two sites, would facilitate recovery of any such material at a later stage if required. Site 2 is thus the preferred site from a maritime archaeology perspective .
8.3 Principal Findings and Key Decision Making Factors The EIA has shown that the environmental impacts associated with the proposed deepening of the Ben Schoeman Dock, and associated upgrades to berths 601, 602, 603 and 604 are in most cases small enough (i.e. rated as insignificant to low) that they are unlikely to have any meaningful influence on a decision regarding the proposed activity. Impacts rated as having medium significance, which should thus influence the decision regarding the proposed project include:
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 150 • Effects of sediment deposition on benthic macrofauna at the disposal site, in the case of disposal of dredge spoil at Site 2;
• Effects of turbidity on habitats surrounding the disposal site, in the case of disposal of dredge spoil at Site 2; and
• The potential introduction of alien species to the selected dredge disposal sites by dredgers and/or hopper barges. The proposed deepening and upgrades of Ben Schoeman Dock, including the disposal of dredge spoil at either of the two potential disposal sites will entail so-called triple bottom line costs, i.e. social, environmental and economic costs. Of the two potential dredge disposal sites assessed as alternatives in this report, Site 1, situated further offshore and thus in deeper water than Site 2, is considered more favourable than Site 2 in terms of marine impacts, although Site 2 would facilitate recovery of marine archaeological material that may be deposited during dredge disposal at a lower cost. In contrast to this, the financial costs of disposing of dredge spoil at the site further offshore will be higher, due to the additional distance, and thus increased traveling times associated with disposal at this site. Initial estimates however indicate that the increased costs associated with disposal at Site 1 would be marginal, with an increase of approximately 10% to the overall dredge costs, compared to disposal at Site 2. Clearly the “mix” of costs across the triple bottom line is different for each site. The challenge (for DEAT) is to take a decision which is sustainable in the long term and which will probably entail tradeoffs between social, environmental and economic costs and impacts. The tradeoffs are implicit in the report, which assesses environmental impacts and compares the sites as well as the nuances associated with each impact and site. SRK believes it will be instructive to reduce the decision factors to the key points which DEAT should consider. These points - social, environmental and economic – constitute the principal findings of the EIA, assuming that the recommended mitigation measures will be effectively implemented, and are as follows: 1. As part of a programme for improving the efficiency of the Port of Cape Town, Transnet proposes to undertake the following activities:
• Deepen the Ben Schoeman Dock ;
• Conduct upgrades to berths 601, 602, 603 and 604; and
• Replacing four of the existing (Demag) cranes with larger Panamax cranes, with the long term intention to increase the number of cranes serving the Dock depending on demand. 2. These upgrades are necessary to accommodate larger container vessels that have a greater draught (i.e. require a greater basin depth) and beam (i.e. width); 3. The deepening of the Ben Schoeman dock will involve the dredging of approximately 1,230,000 m3 of rock and sediment from the basin and will require a small amount of blasting; 4. A number of options for disposal of dredge material were considered during the scoping phase of the project, but were eliminated due to the potential environmental impacts associated with them. Rather, more expensive disposal of dredge spoil at a deepwater site is proposed in order to eliminate or reduce a number of impacts typically associated with disposal nearer shore;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 151 5. Two potential dredge spoil sites - Site 1 and Site 2 - situated approximately 13 km (at a depth of ~65 - 70m) and approximately 9 km from the port (at a depth of ~ 40m) respectively, were identified; 6. In terms of the Dumping at Sea Control Act 73 of 1980, Transnet is required to obtain a permit (from DEAT) to dispose of dredge spoil at sea. In terms of the London Convention of 1972 and the 1996 Protocol (on the Prevention of Marine Pollution by Dumping of Wastes and other Matter):
• The dredge material must be fully characterised and if beneficial uses of the dredge material cannot be identified, a suitable site for disposal needs to be identified and characterised; and
• Potential impacts need to be assessed to inform a dredge disposal permit application. 7. Dredge material (i.e. sediment in the Ben Schoeman basin) was characterised and trace metal concentration of the sediments to be dredged were found to fall within the “special care” category in terms of the London Convention, implying that they are suitable for disposal at sea, although care must be taken in ensuring that impacts are minimised. Sediment in the basin which fall in the “prohibition” category are located outside the area to be dredged; 8. Both of the disposal sites were characterised, prior to the impacts on the site being assessed. Details of the studies undertaken to identify and characterise the two alternative sites were discussed with DEAT Marine and Coastal Management, with whom contact has been maintained throughout the EIA; 9. Most activities and impacts associated with the project are short term in duration; 10. Assessment of impacts on the marine environment have been addressed in this EIA, which along with other specialist studies have aimed to assess the overall impacts of the proposed development and determine the suitability of each of the two potential dredge disposal sites; 11. The majority of the potential impacts on marine ecology were found to be of low significance. The potential introduction of alien species to the selected dredge disposal site is, however, considered to be of medium significance. However this should be viewed in the context of other shipping traffic entering the bay, which could result in a similar effect (although possibly not specifically at the dredge disposal site). Nevertheless, the consequences of the introduction of alien species can be serious if they become invasive; 12. The effects of the disposal of dredge spoil on the ecology and habitats at and surrounding dredge spoil Site 2, including possible effects in the Table Mountain National Park MPA and the Robben Island exclusion zone, were found to be higher than for Site 1, although not to such a degree that Site 2 would be considered “fatally flawed”; 13. Impacts of dredge spoil disposal on shoreline stability are considered negligible provided that the requirements are met in terms of dredge dumping, namely that the dredge material is evenly distributed over the dredge disposal site so as not to cause significant “mounds” of dredge spoil that may start to influence long period waves and consequently shoreline stability; 14. Due to the “instantaneous dumping” method proposed, localized mounds of material (expected to have peak elevations of 0.6 to 0.7m) may be created. This would not result in shoreline stability effects at Site 1, although in terms of the precautionary principle limited wave modeling may be required to confirm potential effects in the case of Site 2 being selected;
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 152 15. Although sedimentation of previously dredged areas and navigation channels are not expected to be significant, the significance and extent of this sedimentation over an extended period of time is difficult to assess. The confidence of this assessment is thus medium to low. Use of the deeper site (Site 1) would best mitigate this, as sedimentation risks are minimized; 16. Interference with existing shipping traffic will occur both within the harbour and during dredge disposal activities, although these risks can be readily managed and reduced to acceptable levels; 17. Although potential impacts on water quality in the harbour were initially of potential concern due to the location of the sea water intake point for the Two Oceans Aquarium in the Victoria and Alfred basin, negotiations are underway with this organisation regarding the monitoring of water quality and suitable mitigation put in place to allow for the aquarium to run on a closed system, or receive a water supply from an alternative sources; 18. Noise and blasting impacts would not be linked to the disposal of dredge spoil and thus have no bearing on the selection of the most suitable dredge disposal site. Based on the estimations of the noise during the construction phase, the following main conclusions can be drawn:
• During construction the noise impact will be area-specific and will last for approximately three years;
• The 70 dBA daytime guideline for industrial districts will not be exceeded outside the site boundary. The same applies to the 60 dBA night-time guideline;
• The constructions at the BSD will have a negligible additional effect on the existing noise levels in the nearby residential areas, i.e. significantly less than an increase of 1 dBA;
• The community in the closest residential area of Woodstock is expected to have no observed reaction since the noise increase will not be noticeable. The same applies to Zonnebloem and Woodbridge Island; and
• Continuous monitoring and optimisation of blasting will ensure compliance with accepted vibration limits at sensitive receptors and buildings. 19. Construction traffic associated with the delivery of materials during the construction phase of the project is expected to have minor impacts on the current traffic on the external access routes, as well as between the construction site and the Contractors Yard, situated at the Culemborg site; 20. As both alternative dredge spoil sites are situated offshore, traffic impacts will have no bearing on the selection of the most suitable dredge disposal site; 21. The proposed activities associated with the deepening of Ben Schoeman Dock and the new gantry cranes are considered to be highly consistent with current activities and congruent with activities associated with a working harbour. Sediment plumes will often be similar to those occurring naturally and will only be visible for very short duration; 22. Although sediment plumes will be larger and more persistent at the shallower of the two sites, the significance of the visual impacts is considered to be very low in both cases and the visual impact should thus have no bearing on the selection of the most suitable waste disposal site; 23. The fact that the basin has been subjected to extensive dredging and blasting in the past has already resulted in destruction of a significant part of the underwater cultural resource. For this
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 153 reason, preference should be given to further development of this basin, as opposed to similar proposed developments; and 24. Disposal of dredge spoil at the shallower of the two sites (Site 2) would facilitate future recovery of any material of archaeological or cultural value that may be disturbed during dredging of the basin. It should be noted that either of the two sites would allow for this, although the associated costs would be higher for the deeper site. SRK believes that sufficient information is available for DEAT to take a decision. If DEAT accepts that the proposed upgrades to the Ben Schoeman Dock are required in order to accommodate new generation vessels, ultimately DEAT must decide which of the two sites evaluated would be most suitable (environmentally) for the disposal of dredge spoil, or if either site would be considered suitable. SRK believes that the specialist studies have shown clearly that the proposed upgrades to the Ben Schoeman Dock, as well as the disposal of dredge spoil at either of the two disposal sites considered, would be environmentally acceptable, assuming the recommended mitigation measures are implemented.
8.4 Recommendations
8.4.1 General Recommendations If DEAT approves the proposed deepening and upgrades to the Ben Schoeman Dock, a condition of approval should be that the recommendations and essential mitigation measures presented below are effectively implemented by Transnet. The general recommendations are to:
• Commit to and effectively implement the essential mitigation measures listed in this EIR;
• Consider implementing the optional mitigation measures listed in this EIR;
• Formulate and implement an Environmental Management Plan (EMP) for the construction and operational 33 phase of the project (if approved), incorporating: − methods to mitigate environmental impacts during construction; and − assigned responsibilities for the implementation of the EMP;
• Apply for the necessary permit for the disposal of dredge spoil at sea from DEAT, prior to such disposal taking place;
• Apply for the necessary permits from SAHRA in the case of material of cultural value being encountered;
• Formulate or make known a mechanism to receive and address complaints
• Continue to keep local stakeholders informed of future plans in this regard.
33 The NPA Environmental Management System (EMS) will also be applicable to the operational phase of the project.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 154 8.4.2 Specific Recommendations and Mitigation Measures It is assumed that the following essential mitigation measures, designed to manage impacts associated with the proposed deepening of the Ben Schoeman Dock, and upgrades to Berth 601-604 will be implemented if the proposed project is approved. The mitigation measures listed below are applicable in the case of disposal of dredge spoil at either of the two alternative disposal site. 34 Optional mitigation measures, which would further assist in reducing the environmental impacts associated with the proposed development, but the implementation of which cannot be guaranteed (and have thus not been considered in the assessment of the significance of environmental impacts) have also been listed. These mitigation measures should be considered by Transnet, who should have suitable motivation if not implemented.
Potential Marine Impacts Essential mitigation measures: 1. Apply the relevant ballast water management protocols stipulated in the IMO International Convention for the Control and Management of Ship's Ballast Water and Sediments as well as NPA requirements for ballast water management, with verification of application; and 2. Dispose of dredged material in such a way that an average mound elevation of 0.3m is achieved in order to prevent unexpected wave refraction effects occurring, particularly at Site 2. 3. Include specifications of turbidity levels not to be exceeded at the entrance/exit to Ben Schoeman Dock in the Environmental Management Plan and Dredge Tender documents. Recommended levels are likely to range from 80 to 100mg/l, but will need to be both reasonable and sufficiently conservative to mitigate specific predicted environmental impacts. It is best left to the dredge operators to select appropriate mitigation measures to meet these specifications, rather than specifying these in the Environmental Management Plan. The EMP should however make allowance for monitoring of these levels. Optional mitigation measures include: 1. Lure seals, marine mammals and marine birds out of Ben Schoeman Dock to sea during blasting periods. 2. Should a Cutter Suction Dredging be chosen undertake dredging during summer rather than winter; 3. Ensure that sediments are deposited in thin layers when discharged at the sediment disposal site, in an attempt to achieve a fairly even sediment distribution, rather than mounds, to reduce mortality of benthos; 4. Prevent the chronic build up of turbidity in the area of the dredge disposal site through allowing sufficient time for turbidity to disperse between dump events, thus reducing impacts on penguin populations foraging in the area; 5. Dispose of dredge spoil at Site 1 rather than Site 2;
34 Where mitigation measures recommended in specialist studies have not been considered practical, SRK has amended these in the EIR.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 155 6. In the case of Site 2 being selected as the dredge disposal site, undertake a limited wave modelling study for this site, to confirm the effect of uneven dumping on the wave climate is sufficiently limited to prevent changes in shoreline stability; 7. Reassess the potential impacts on the marine environment in the case of dredge technology, nature of operations or durations being significantly different to those assessed in the specialist study (based on current project description provided in Chapter 3); 8. Confirm the potential remobilization of toxins with additional (more comprehensive) elutriation analyses of the sediments targeted to be dredged, prior to dredging; 9. If possible, find a beneficial use for rock to be removed from the basin; 10. Obtain an appropriate environmental baseline for the potential impacts from dredging operations (e.g. water quality at the Two Oceans Aquarium intake). The baseline should specifically be obtained for “indicator” trace metals (copper and zinc) and suspended sediments (and possibly nutrient, particularly ammonium levels). These quantities are to be appropriately monitored at the Two Oceans Aquarium during the dredging operations. 11. In the case of water quality at the intake point not being suitable for use by the aquarium and attributable to dredging or dredge disposal activities, the implementation of mitigation measures (e.g. running of a closed system, or obtaining seawater from elsewhere) should be considered. Optional monitoring with respect to marine impacts include: 1. Utilise survey data gained on the candidate dump sites to track changes associated with dredge spoil dumping over a realistic time span to show rates of benthos recovery and provide information on dumped dredge spoil behaviour. Opportunities for this have not been created in the past and the baseline data set will be an invaluable tool in understanding the effects and implications of the marine disposal of dredge spoil on South Africa's inner continental shelf. 2. Undertake further simulation modeling analyses of the life cycles and distributions of dredge spoil dump site surface layer turbidity plumes throughout the various phases of the dredging programme. In terms of the possible effects on African Penguins foraging in Table Bay, this may lead to mitigation solutions based on timing of the various phases of dredging and spoil dumping. Although the evaluation of the predicted effects on penguins yielded a low significance rating, public perceptions merit serious attention being given to efforts to ameliorate any possible impacts. 3. Monitor beneficial use areas of the V&A waterfront such as filter performance levels at the Two Oceans Aquarium and through real time monitoring (instrumented buoy and telecommunication system) located near the entrance to the harbour. The buoy system would also allow real time control of the dredging operations in terms of limiting exceedances of critical suspended sediment concentrations such as those envisaged in EMBECON (2004). 4. Operate a mussel watch programme (through DEAT/MCM) that incorporates sampling points around the Port of Cape Town. Sampling intervals in this programme are six months. During the dredging period it is recommended that monthly coverage is requested to show short term effects, if any, of remobilised contaminants in filter feeders. This monitoring can be augmented by suspension of mussels adjacent to the selected dredge spoil dump site to confirm that released or remobilised contaminants are below any level of concern.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 156 5. Utilise the monitoring of the proposed dredging operation, together with supplementary measurements, to better constrain uncertainties in the model predictions. In particular, measurements supporting the more accurate specification of critical shear stresses of deposition, critical shear stresses of erosion and re-suspension rates at the seabed, should be taken.
Potential Noise, Shock and Vibration Impacts No essential mitigation measures are required to reduce the noise and blasting impacts associated with the project. Optional mitigation measures: 1. Maintain construction equipment and ensure that silencer systems function efficiently at all times; 2. Position stockpiled materials so as to provide screening and reduce noise from specific construction operations beyond the site boundaries; 3. Notify occupants of surrounding areas, as well as divers of proposed blasting activities at predetermined times on stated days; 4. Carefully design the blasting regime to reduce the levels of ground borne vibration; 5. Design and carry out blasting operations with due regard to good blasting practice. This would include:
− Calculating the charge size and timing delay to keep ground vibration levels below pre- determined acceptable values;
− Correct stemming of blast holes to reduce noise and vibration generation and improve blasting efficiency.
− Monitoring of ground vibration and human response by an independent third party entity to ensure that agreed levels are in fact acceptable to the occupants of surrounding areas and are being adhered to, and to modify the blasting design if required to reduce impacts. 6. Undertake a set of test blasts prior to the start of the main blasting operations, in order to determine the two site-specific coefficients which would allow for the calculation of the actual peak particle velocity at sensitive buildings, so that levels can be controlled by competent blast design. Optional monitoring of noise would include: 1. Undertake biannual noise monitoring along the site’s boundaries during the construction period in order to ensure conformity with the regulations and indicate relevant corrective measures to be implemented. The measurements should be performed in accordance with procedures stipulated in the South African National Standard (SANS) Code of Practice: SANS 10103:2004.
Potential Traffic Impacts Essential mitigation measures: 1. Schedule the bulk of arrivals and departures of truck conveying construction material during the commuter inter-peak period (between 09h00 and 16h00);
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 157 2. Implement a stop control at the contractor’s yard access road approach to Duncan Road; and 3. Deploy a traffic marshal at the crossing of the access road from the Contractors yard with the Harbour and Paarden Eiland rail lines. The traffic marshal is to maintain communication with the train operators at the central traffic control centre with regard to train movements.
Potential Visual Impacts No Essential mitigation measures are required to reduce the visual impacts associated with the project. Optional mitigation measures: 1. Consider the visual impacts of sediment plumes in selection of the most suitable dredge method. 2. Limit the area used for construction activities including the associated storage of waste, materials and equipment; 3. Ensure that rubble and waste material are removed regularly from the site; 4. Store construction equipment and material in an orderly manner on a designated site; 5. Unless considered a safety risk, paint cranes a colour that will be least visible against the skyline (grey/blue); and 6. Monitor and react to complaints about plumes generated by project activities. .
Potential Archaeological Impacts Essential mitigation measures: 1. Where applicable, take the recommendations of the Maritime Archaeologist into account when planning and conducting blasting and dredge operations to minimize impacts on the potential cultural resource; 2. Inform both NPA and SAHRA of the exact location and extent of the dredge disposal site; 3. Ensure that all contractors and subcontractors are made aware of the potential existence of underwater heritage resources, and instructed on the correct procedure for preserving the integrity thereof. Also instruct sub-contractors to monitor dredging activities (through visual inspection of at least part of the dredge material brought to the surface before being deposited at the disposal site, where possible) for any cultural material that may be uncovered. In the case of material being uncovered, a qualified archaeologist is to be notified immediately and the material secured and kept for inspection; 4. Ensure that monitoring is particularly vigilant during dredging of the area from Berth 603 westwards; 5. Formally inform SAHRA in writing of the planned development; 6. Retain a suitably qualified archaeologist as a consultant for the duration of the dredging operations to provide advice to the Contractor as and when required. This person may have to: liaise with SAHRA and the client / dredger operators; pay ad hoc site visits to monitor blasting and dredging activities; secure the necessary licences and permits from the Controller of
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 158 Customs and Excise and the SAHRA; and render assistance should any cultural material be dredged up; 7. Provide assistance should the maritime archaeologist deem it necessary to undertake an underwater survey and/or remove material. This may include support from NPA divers and others; 8. Make provisions for essential mitigating activities related to underwater cultural material that may be recovered. This would include:
− making funds available for monitoring activities to be undertaken by the project’s maritime archaeologist if required;
− funding for potential limited underwater fieldwork if required;
− funding for the basic preservation and documentation of dredged up material if required; and
− allocation of a suitable area where recovered material may be temporarily stored and treated if required; and 9. Allow for any valuable material recovered during dredging to be adequately stored and preserved. Excavation and recovery can only be done after a licence from the Department of Customs and Excise has been issued and a permit from the SAHRA has been obtained. Optional mitigation measures are: 1. Where practicable and cost effective, preferably make use of a backhoe dredger, which allows for visual monitoring of the dredge spoil before it is removed. This is especially the case in the archaeologically sensitive area from berth 603 towards the entrance channel; and 2. Preferably dispose of dredge spoil in an area that will allow future recovery of heritage resources. It should be noted that either of the proposed dredge disposal sites would allow for this, although the associated costs would be higher for a deeper site.
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 159 9 Way Forward The Environmental Impact Report has identified and assessed potential impacts associated with the proposed deepening of the Ben Schoeman Dock and upgrades to Berths 601-604 at the Port of Cape Town. It is not a final report and will be amended based on comments received from IAPs. Further opportunities to comment on the EIR are indicated below. The Executive Summary of the Draft EIR has been sent to all identified IAPs. The EIR is being released for a 30-day review period commencing on 12 February 2007 and ending on 13 March 2007. The full report and appended specialist studies can be viewed as follows:
• At the Cape Town Library
• At the Milnerton Library;
• At the SRK Office, Rondebosch, Cape Town;
• As an electronic copy on Transnet’s website www.transnet.co.za/TransnetProjects.aspx (on the Home page select “Doing business with Transnet” followed by “Transnet Projects”); and
• Upon request, full hard copies of the Draft EIR can also be mailed to stakeholders at a cost of R250 (incl. VAT) and / or a copy (excluding maps, diagrams and appendices) can be emailed free of charge. A CD can also be prepared and mailed at a cost of R30. IAPs are also invited to attend a Public Open Day, which will be held on 27 February 2007, where the information presented in the Draft EIR can be discussed. Representatives from Transnet and SRK will be available for discussion regarding the findings presented in the Draft EIR. Please note that the Open Day is open to all members of the public but will not be convened as a conventional public meeting with presentations by the EIA team and a set agenda. Details of the Public Open Day are as follows: Venue: 10 th Floor, NPA House, Port of Cape Town Date: 27 February 2007 Time: 15h00 – 19h00 Written comments on the Draft EIR should be submitted by 13 March 2007 to: Sharon Jones SRK Consulting Tel: 021 – 659 3060 Postnet Suite #206 Fax: 021 – 685 7105 Private Bag X18 Email: [email protected] Rondebosch 7701
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 160 Once IAPs have commented on the information presented in the Draft EIR, the Final Environmental Impact Report will be submitted to DEAT for their decision.
SHARON JONES CHRIS DALGLIESH Environmental Scientist Principal Environmental Scientist SRK CONSULTING
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 161 10 References CSIR (2006a). Ben Schoeman Dock Berth Deepening Project: Integrated Marine Impact Assessment Study. CSIR Report No CSIR/NRE/ECO/ER/2006/Draft. CSIR (2006b). Ben Schoeman Dock Berth Deepening Project: Dredging and Disposal of Dredge Spoil Modelling Specialist Study. CSIR Report No CSIR/NRE/ECO/ER/2006/Draft. CSIR (2006c). Assessment of the Potential Effects of Dumping Material from Ben Schoeman Basin on Shoreline Stability in Table Bay. CSIR Report No CSIR/NRE/ECO/ER/2006/0205/C. CSIR (2006d). Ben Schoeman Dock Berth Deepening Project: Dredge Spoil Characterisation and Dredge Disposal Site Selection and Characterisation. CSIR Memorandum JMCP173/01. CSIR (2004a). Strategic Environmental Assessment Port of Cape Town Sustainability Framework. CSIR (2004b). Final Environmental Impact Report: Proposed Expansion of the Container Terminal Stacking Area at the Port of Cape Town. CSIR (1991). First Report on The Situation of Waste Management and Pollution Control in South Africa, Report to Department of Enviroment Affairs by the CSIR Programme for the Environment, Pretoria. Report CPE 1/91. DDA (2006). Noise and Vibration Impact Assessment Study for the Ben Schoeman Dock Deepening. DWAF (Department of Water Affairs and Forestry) (1995). South African Water Quality Guidelines for Coastal Marine Waters. Volume 1: Natural Environment. Entech and CSIR (2006). Removal of Rock in the Port of Cape Town. European Dredging Association (EDA). http://www.european-dredging.info/ab7.html . Accessed September 2006. HHO Africa (2006a). Ben Schoeman Dock Deepening Environmental Impact Assessment: Traffic Impact Assessment. HHO Africa (2006b). Port Of Cape Town: Container Terminal Expansion - Temporary Construction Access. Lwandle Technologies (2006a). Ben Schoeman Dock Berth Deepening: Specialist Study on Sediment Toxicology and Marine Ecology. Job No 06-35. Lwandle Technologies (2006b). Port of Cape Town: Dredge Spoil Dump Site Selection: Marine Survey Summary Cruise Report. Job No 06-35. Schoonees, J.S. (2006). Dredge Disposal Options for the Deepening of the Port of Cape Town (Draft). Report No. EN/CO/205506/1/March 2006. Shangoni Management Services (2006). Final Scoping Report: Proposed Alterations to Berths 601, 602, 603 and 604 and Associated Deepening of the Ben Schoeman Dock at the Port of Cape Town. Werz, B.E.J.S. (2006). Environmental Impact Assessment for the Proposed Deepening of the Ben Schoeman Basin and Alteration of Berths 601, 602, 603 and 604, Port of Cape Town: Specialist Study in Maritime Archaeology
JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007 SRK Consulting BSD Deepening EIR Page 162 SRK Report Distribution Record Complete this form and include it as the final page for each copy of the report produced.
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Name/Title Company Copy Date Authorised by The Librarian Cape Town Library 1 12/02/07 S. Jones The Librarian Milnerton Library 2 12/02/07 S. Jones John Geeringh DEAT 3 12/02/07 S. Jones Melanie Webber DEA&DP 4 12/02/07 S. Jones Jonathan Sharfman SAHRA 5 12/02/07 S. Jones Rudie Basson Transnet 6 12/02/07 S. Jones Miriam Tenyane NPA 7 12/02/07 S. Jones Yazeed Peterson DEAT: MCM 8 12/02/07 S. Jones Johan Spies CPHMG 9 12/02/07 S. Jones Ellen Campbell CPHMG 10 12/02/07 S. Jones Sharon Jones SRK Consulting 11 12/02/07 S. Jones SRK Library SRK Consulting 12 12/02/07 S. Jones
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JONS/REUT 367079_Transnet_Draft Berth Deepening EIA for public review February 2007