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Defence Infrastructure Organisation Thanckes Oil Fuel Depot Loading Facility and Tank Farm Fire Fighting Upgrade Environmental Statement
Volume 2: Main Text
Hyder Consulting (UK) Limited 2212959 5th Floor The Pithay All Saints Street Bristol BS1 2NL United Kingdom Tel: +44 (0)117 372 1200 Fax: +44 (0)117 37 www.hyderconsulting.com
Defence Infrastructure Organisation Thanckes Oil Fuel Depot Loading Facility and Tank Farm Fire Fighting Upgrade Environmental Statement
Volume 2: Main Text
Various. Compiled Sarah Author Hart
Checker David Hourd
Approver James Prescott
Report No 5402-UA004737-UE31R-02
Date 13 April 2015
This report has been prepared for Defence Infrastructure Organisation in accordance with the terms and conditions of appointment for PSP Support dated 11 th July 2002.
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CONTENTS
Volume 1: Non-Technical Summary
Volume 2: Main Text
1 INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 Site Location ...... 1 1.3 Legal Basis Environmental Statement ...... 2 1.4 Structure of Environmental Statement ...... 4 1.5 Inspection of the Environmental Statement ...... 4 2 THE PROJECT ...... 5 2.1 Project Context ...... 5 2.2 Need For The Project ...... 6 2.3 Site Operations and Maintenance ...... 7 2.4 Project Description ...... 8 2.5 Design Considerations ...... 11 2.6 Indicative Construction Method ...... 12 2.7 Project Programme ...... 20 2.8 Alternatives Considered ...... 21 3 ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY ...... 26 3.1 Introduction ...... 26 3.2 Legislation and Guidance ...... 26 3.3 Scoping of Environmental Topics ...... 26 3.4 Environmental Impact Assessment General Methodology ...... 29 3.5 Consultation ...... 30 3.6 Assessing Cumulative Effects ...... 34 3.7 Other Relevant Consents, Licences and Assessments ...... 36 4 PLANNING POLICY CONTEXT ...... 39 5 WATER, CONTAMINATION AND SEDIMENT QUALITY ...... 40 5.1 Introduction ...... 40 5.2 Regulatory and Policy Framework ...... 40 5.3 Methodology ...... 42 5.4 Description of the Baseline Conditions ...... 50 5.5 Design and Mitigation ...... 61 5.6 Assessment of Effects ...... 68
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5.7 Cumulative Effects ...... 69 5.8 Summary ...... 70 6 ECOLOGY ...... 73 6.1 Introduction ...... 73 6.2 Regulatory and Policy Framework ...... 73 6.3 Methodology ...... 80 6.4 Description of the Baseline Conditions ...... 87 6.5 Selection of Ecological Receptors ...... 111 6.6 Design and Mitigation ...... 116 6.7 Assessment of Effects ...... 130 6.8 Cumulative Effects ...... 143 6.9 Enhancement measures ...... 144 6.10 Summary ...... 144 7 ARCHAELOGY AND CULTURAL HERITAGE ...... 150 7.1 Introduction ...... 150 7.2 Regulatory and Policy Framework ...... 150 7.3 Methodology ...... 152 7.4 Description of the Baseline Conditions ...... 163 7.5 Design and Mitigation ...... 165 7.6 Assessment of Effects ...... 167 7.7 Summary ...... 169 8 NOISE AND VIBRATION ...... 171 8.1 Introduction ...... 171 8.2 Regulatory and Policy Framework ...... 171 8.3 Methodology ...... 172 8.4 Description of the Baseline Conditions ...... 179 8.5 Design and Mitigation ...... 180 8.6 Assessment of Effects ...... 182 8.7 Cumulative Effects ...... 187 8.8 Summary ...... 188 9 LANDSCAPE AND VISUAL IMPACT ASSESSMENT ...... 190 9.1 Introduction ...... 190 9.2 Regulatory and Policy Framework ...... 190 9.3 Methodology ...... 191 9.4 Description of the Baseline Conditions ...... 194 9.5 Design and Mitigation ...... 197 9.6 Assessment of Effects ...... 197 9.7 Cumulative Effects ...... 200 9.8 Summary ...... 200 10 Conclusion ...... 202 GLOSSARY AND ABBREVIATIONS...... 205 REFERENCES ...... 212
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Volume 3: Drawings
1-1 Site Location 1-2 Aerial View of Site Location 1-3 Application Boundary 1-4 Designated Sites within 2.5km study area 2-1a Existing structures sheet 1 of 2 - plans and section 2-1b Existing structures sheet 2 of 2 - overall layout 2-2 General Arrangement drawing 1 2-3 General Arrangement drawing 2 2-4 Setting out details plan 2-5 Berthing pocket 2-6 Jetty Head plan 2-7 Berth pocket relocation 2-8 Navigation Plan 2-9 Proposed tank drenching system 2-10 Fire fighting System Proposed Fire Main Pipe Plan 3-1 Cumulative Effects 5-1 Surface Water Features 5-2 Sediment Sample locations – June 2013 and 1984 borehole locations 5-3 Proposed Jetty borehole location plan 6-1 Phase 1 Habitat Survey 6-2 Designated sites within 5km study area 7-1 Recorded heritage assets 7-2 Location of boreholes taken within and in the vicinity of the site. Data available for numbered boreholes. 7-3 Extract from the 1643 Hollar Seige Map, position approximate 7-4 Extract from a chart dating to 1774 7-5 Extract from 1798 chart of Plymouth Sound 7-6 Extract from 1840 Tithe Map of Anthony 7-7 Extract from 1887 Chart 7-8 Impacts associated with the proposed Development. 7-9 Historic Photographs showing vessels moored in the vicinity of the Site 8-1 Baseline Noise Monitoring Locations 9-1 Zone of theoretical visibility and designated sites within 2.5km study area 9-2 Viewpoints 1 and 2 - Sheet 1 of 4 9-3 Viewpoints 3 and 4 - Sheet 2 of 4 9-4 Viewpoints 5 and 6 - Sheet 3 of 4 9-5 Viewpoints 7 and 8 - Sheet 4 of 4 9-6 Photomontage A (Viewpoint 2) 9-7 Photomontage B (Viewpoint 4)
Volume 4: Appendices
1-A Marine Conservation Zone Designation Features 1-B Screening/Scoping Request Letter 1-C Scoping Report 1-D Screening Opinion from Cornwall Council 1-E Scoping Opinion from Cornwall Council 1-F Screening & Scoping Opinion from Marine Management Organisation
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2-A Piling Restriction 3-A Hydrodynamic Technical Paper 3-B Update letter to consultees 3-C Assessment Study Consultations 3-D EIA Consultation Log 3-E MMO Marine Licencing Guidance 3-F Minutes of External Stakeholder EIA Scoping/HRA Screening Consultation Workshop 3-G Assessment of Effects workshop minutes 3-H Underwater Noise / Impact on Fish Meeting Minutes 3-I Public Exhibition Feedback Form 3-J Parish Council Update 5-A Water Framework Directive Assessment 5-B Soil Mechanics 1984 Borehole Logs 5-C Public Register Information 5-D Historical Maps 5-E Plymouth Sound Chemical Information 5-F Site Sediment Analysis Data 2013 5-G Information on Action Levels and Canadian Effect Levels 5-H Waste Classification 6-A Bird Count Data 6-B Target Notes 6-C Tamar Report 6-D HRA Screening 6-E Conservation objectives for Plymouth Sound and Estuaries European Marine Site 6F Migratory fish species present in the Tamar Estuary 6G Confirmation of Natural England’s Opinion on European Smelt 7-A Gazetteer 7-B Detailed Baseline Information 8-A Baseline Noise Survey 8-B Construction Noise Assessment
List of Tables
2-1 Existing and Proposed Development Areas 2-2 Moat Uses and Capacities 2-3 Separator Function and Operation 2-4 Key planning and project milestones 2-5 Environmental and sustainability considerations 3-1 Determining significance 5-1 Regulatory References 5-2 Criteria for Determining the Value (Sensitivity) of the Hydrological Resource 5-3 Criteria for the Assessment of Overall Effect 5-4 Classification of Potential Consequence (Severity) 5-5 Classification of Probability (Only applies if there is a possibility of a pollutant linkage being present) 5-6 Classification of Risk 5-7 Risk Classification Descriptions 5-8 Consultation Responses 5-9 Summary of Historical Potential Sources of Contamination 5-10 Summary of Recent Potential Sources of Contamination 5-11 Summary of Contamination Risk Assessment 5-12 Water, Contamination and Sediment Quality - Impact Summary Table
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6-1 Ecology Regulatory and Policy Framework 6-2 Assessment of significance 6-3 Consultation responses 6-4 BTO WeBS data compared with October 2009 survey results 6-5 Results of Marine and Intertidal Surveys 6-6 Migratory fish species present in the Tamar Estuary 6-7 Selection of Key Ecological Receptors 6-8 Current and anticipated habitat loss 6-9 Cumulative unmitigated noise impacts of piling the jetty approach, the jetty head and the mooring dolphins 6-10 Cumulative unmitigated noise impacts during demolition 6-11 Ecology Impact Summary Table 7-1 Determining the Importance / Sensitivity of Resource 7-2 Assessment of the Magnitude of Change 7-3 Determination of the Significance of Effect 7-4 Qualitative Description of the Significance of Effect 7-5 Consultation responses 7-6 Archaeology and Cultural Heritage Impact Summary Table 8-1 Regulatory and Policy Framework 8-2 Recommended indoor ambient noise levels BS 8233: 2014 8-3 Example of Threshold of Significant Effect at Dwellings (Table E1 in BS5228) 8-4 Criteria for the rating of noise impacts during construction 8-5 Determining the Importance / Sensitivity of Resource 8-6 Significance of Noise Impact 8-7 Consultation responses 8-8 Noise monitoring location and sensitive receptor locations 8-9 Summary of Baseline Noise Survey Data 8-10 Significance of Predicted Weekday Daytime Construction Noise Impacts 8-11 Significance of Predicted Dredging Noise Impacts 8-12 Significance of Predicted Weekend Daytime Construction Noise Impacts 8-13 Calculated Noise Limit for Operational Plant to be Installed on Site 8-14 Noise Impact Summary Table 9-1 Landscape and Visual Regulatory and Policy Framework 9-2 Definitions of Landscape Sensitivity 9-3 Definitions of Visual Sensitivity 9-4 Assigning Magnitude of Landscape Impact 9-5 Assigning Magnitude of Visual Impact 9-6 Significance Matrix 9-7 Landscape and Visual Impact Summary Table List of Figures
2-1 Aerial view of the Yonderberry Jetty 2-2 Contractor’s Compound 2-3 Contractor’s Working Area: Jetty Head 6-1 Distribution of avocet within the Tamar Estuaries Complex SPA at low tide 2002/03 6-2 Tamar Estuary (South) Sector 10 6-3 Tamar Complex 6-4 Distribution of little egret at low tide, winter 2002/3 6-5 Results of inter-tidal survey 6-6 Results of subtidal survey
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1 INTRODUCTION 1.1 Background
Defence Infrastructure Organisation (DIO) has appointed Hyder Consulting Ltd (herein referred to as ‘Hyder’) to submit planning and marine consent applications for the replacement of a jetty in the Hamoaze 1 and the upgrade of associated fire-fighting infrastructure at Thanckes Oil Fuel Depot (OFD). The existing jetty, named Yonderberry Jetty, will be demolished upon completion of the new structures and there will also be relocation of the existing berth pocket. The proposed site location is shown on Drawing 1-1.
This Environmental Statement (ES) reports the findings of the Environmental Impact Assessment (EIA) for the project and it applies to both the Planning Application and the Marine Licence Application. The ES describes the project, the baseline environment and the significant and non- significant environmental effects after mitigation. The purpose of the ES is to ensure that the likely effects of the Development on the environment are fully understood and taken into account before any decision by the consenting authorities (Cornwall Council (CC), and the Marine Management Organisation (MMO)) is taken.
Due to the nature of this planning application the ES should be read in conjunction with the following supporting documents:
• Planning Statement
• Design and Access Statement
• Statement of Community Involvement 1.2 Site Location
The Thanckes OFD lies on the west bank of the Hamoaze opposite the north yard of Her Majesty's Naval Base (HMNB), Devonport. The Hamoaze forms part of the Tamar Estuary which forms the border between Devon and Cornwall (Drawing 1-1). An aerial view of the proposed site location can be found on Drawing 1-2 and the indicative boundary for the project can be found on Drawing 1-3. The site is located on a headland with a maximum elevation of 35 metres above ordnance datum (mAOD) at the site entrance and minimum elevation of approximately 2m AOD at the perimeter of the site above the estuary foreshore. The estuary system is a large marine inlet comprising the estuaries of the rivers Tamar, Lynher and Tavy which collectively drain an extensive part of Devon and Cornwall. The River Tamar and its tributaries provide the main input of fresh water into the estuary complex, and form a ria (drowned river valley) with Plymouth lying on the eastern shore.
The high quality of the natural environment is reflected by the large number of national and international designations protecting the area (Drawing 1-4). The Plymouth Sound and Estuaries are designated a Special Area of Conservation (SAC) under the European Habitats Directive (92/43/EEC) (Ref 1-1) and parts are also designated as Special Protection Areas (SPA) under the Birds Directive (79/409/EEC) (Ref 1-2). The two designated areas collectively form a European Marine Site. The Yonderberry Jetty lies partially within the SAC. The mudflats adjacent to the shore, within the site, are within an Area of Great Scientific Value.
1 The Hamoaze is an estuarine stretch of the River Tamar between the River Lynher and Plymouth Sound.
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There are also two Marine Conservation Zones (MCZ) within the vicinity of the project (Drawing 1-4); Tamar Estuary Sites to the north and Whitsand and Looe Bay to the south (shown on Drawing 1-4). These MCZs were designated under the Marine and Coastal Access Act 2009 (Ref 1-3) as part of the first tranche of designations in November 2013. Further information on the features of the relevant MCZs can be found in Appendix -1A.
The project is also located within the wider landscape context is the Tamar Valley Area of Outstanding Natural Beauty (AONB).
There are a large number of maritime and port facilities within the estuarine complex. The Tamar Estuaries Consultative Forum (TECF) has been established to improve management and to implement the Plymouth Sound and Estuaries Marine Site Management Plan. The work of the TECF is currently guided by the Tamar Estuaries Management Plan 2013 to 2018 (Ref 1-4). 1.3 Legal Basis Environmental Statement
EIA is a procedure for ensuring that the likely environmental effects of a new development are properly understood by the public and relevant competent authorities, before a decision is made to grant planning and marine consent.
The Project has been considered under the Town and Country Planning Act 1990 (as amended) (Ref 1-5), the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (Ref 1-6), Marine and Coastal Act, 2009 (Ref 1-3) and the Marine Works (Environmental Impact Assessment) Regulations 2007 (as amended) (Ref 1-7) which implement EC Directive 2011/92/EU (as amended) (Ref 1-8).
The project is considered to be a ‘Schedule 2’ development under the Town and Country Planning (EIA) Regulations 2011 and an Annex II project under the Marine Works (EIA) Regulations 2007. A formal EIA is required due to the projects scale and nature and the site’s proximity to sensitive areas (there are a number of sites designated for their ecological importance in close proximity to the Project site, as outlined in section 1.2).
A formal screening request was issued to the consenting authorities (CC and MMO) on 17 December 2012 (Appendix 1-B), this was accompanied by a scoping report (Appendix 1-C).
A screening opinion was received from CC (Appendix 1-D) on 19 February 2013 and a subsequent scoping opinion (Appendix 1-E) was received on 1 March 2013 (letter dated 13 February 2013). CC confirms that an EIA is required for the proposed development. CC have made their decision with regard to the criteria set out within Schedule 2 (10 (m) Coastal work to combat erosion and maritime works capable of altering the coast through the construction, for example, of dykes, moles, jetties and other sea defence works, excluding the maintenance and reconstruction of such works ); with appropriate consideration to Schedule 3 of the Town and County Planning (Environmental Impact Assessment) Regulations 2011, in particular paragraph 3 (i), and the Governments Guidance contained within Circular 02/99 – Environmental Impact Assessment.
A screening and scoping opinion was received from the MMO (Appendix 1-F) on 27 March 2013. The MMO determined that a statutory EIA under the Marine Works (Environmental Impact Assessment) Regulations 2007 (as amended) was required for this proposal under Annex II ‐ 10 (k): Coastal work to combat erosion and maritime works capable of altering the coast through the construction, for example, of dykes, moles, jetties and other sea defence works, excluding the maintenance and reconstruction of such works .
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The iterative nature of the design process has resulted in a revision to the jetty location, inclusion of the tank farm fire-fighting upgrade and other design amendments. Full details of the design and alternatives are covered in Chapter 2 and details of consultation are covered in Chapter 3.
Based on further consultation with regard to the design revision, as detailed in Chapter 3 the scoping opinions received from both the MMO and CC are still valid.
The scoping opinions identified that the development could potentially have significant environmental effects on the following topic areas:
° Water Quality, Sediment Quality, Geology & Contamination ° Marine & Terrestrial Ecology ° Archaeology & Cultural Heritage ° Noise & Vibration ° Landscape & Visual The EIA has been prepared on this basis. Further details of the screening and scoping are discussed in Chapter 3.
In addition to observing the formal requirements of the EIA Directives (Ref 1-8) and the EIA Regulations (Ref 1-6 & 1-7), further formal guidance has informed the assessment. Examples include; the National Planning Policy Framework 2012 (NPPF) (Ref 1-9); and the Institute of Environmental Management and Assessment’s (IEMA) Guidelines for Environmental Impact Assessment 2004 (Ref 1-10).
Information that should be included within an ES in accordance with Schedule 3 of the Marine Works (EIA) Regulations 2007 and Schedule 4 of Town and Country Planning (Environmental Impact Assessment) Regulations 2011, is as follows:
• a description of the development
• an outline of the main alternatives studied by the developer and an indication of the main reasons for the choice, taking into account the environmental effects
• a description of the aspects of the environment likely to be significantly affected by the development including, in particular, population, fauna, flora, soil, water, air, climatic factors and material assets including the architectural and archaeological heritage, landscape and the inter-relationship between the above
• a description of the likely significant effects of the development on the environment, which should cover the direct effects and any indirect, secondary, cumulative, short, medium and long-term, permanent and temporary, positive and negative effects of the development
• a description of the measures envisaged to prevent, reduce and where possible offset any significant adverse effects on the environment.
• a non-technical summary
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1.4 Structure of Environmental Statement
The ES is structured as follows:
• Volume 1 - The Non-Technical Summary (NTS) summarises the principle sections of the ES in non-technical language to make it readily understandable by members of the public.
• Volume 2 – the ES main text (this volume): explains the purpose of the proposal (Chapter 1); describes the project and summarises alternatives considered (Chapter 2); explains the overall approach to the EIA and alternatives (Chapter 3); and, within Chapter 4, refers to planning policy context. It presents the mitigation measures and draws together the significant environmental effects after mitigation for each environmental topic in Chapter 5 to 9.
• Volume 3 – contains the ES drawings referred to in Volume 1 ES main text.
• Volume 4 – contains the ES appendices referred to in Volume 1 ES main text. 1.5 Inspection of the Environmental Statement
A copy of the ES has been submitted to CC and the MMO to accompany the planning and marine consent applications respectively. The ES will be available to the public for inspection for the duration of the consultation period (3 weeks for the CC and 6 weeks for MMO) at the following location.
Cornwall Council Offices Planning and Regeneration Cornwall Council 3-5 Barn Lane Bodmin, PL31 1LZ
The documents will also be available to view through Cornwall Council online planning register ( http://www.cornwall.gov.uk/environment-and-planning/planning/online-planning- register/ ), in addition to the MMO’s Marine Case Management System (https://marinelicensing.marinemanagement.org.uk/mmo/fox/live/MMO_PUBLIC_REGISTER #South_Western ).
All interested parties are invited to comment in writing on the ES and the dates for consultation will be publicised through the CC and MMO websites. Comments should be sent to CC at the following address:
FAO Michelle Billing Cornwall Council Offices Planning and Regeneration Cornwall Council 3-5 Barn Lane Bodmin, PL31 1LZ
Comments for the MMO should be emailed to [email protected] .
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2 THE PROJECT 2.1 Project Context
Thanckes OFD was built in the 1920’s and occupies a 39ha peninsula site on the banks of the River Tamar directly opposite the north yard of HMNB Devonport. Thanckes OFD comprises Yonderberry fuelling jetty and storage tanks that are used to store diesel, aviation fuel, hazardous oily waste (known as sullage) and firefighting water, together with an extensive network of pipelines, pumps, filtration equipment and containment moats.
From 1st April 2013 Thanckes OFD came under the management and control of The Oil & Pipelines Agency (OPA), who have a service agreement to manage the asset on behalf of the Ministry of Defence (MOD). The OPA are the safety duty holder for the site, operating under the Control of Major Accident Hazard regulations 1999 (COMAH) (Ref 2-1). Thanckes OFD has a total storage capacity for class 3 fuels that exceeds the upper tier COMAH threshold of 25,000 tonnes of named substances under amendments to the COMAH regulations in 2002.
The COMAH Regulations are regulated by the Competent Authority (Health & Safety Executive (HSE) and the Environment Agency (EA)). As a crown property the buildings also fall under the regulatory authority of the Crown Premises Fire Inspection Group (CPFIG). CPFIG is a regulatory body and following discussions have deferred all matters relating to the fire safety for this project to the HSE.
Yonderberry Jetty is the depot’s primary issue and receipt facility. It is capable of berthing tankers of up to 50,000 displacement tonnes, plus the numerous marine services craft used to transfer fuel and sullage to and from warships berthed in HMNB Devonport. The role of Yonderberry Jetty is fundamental to the operation of Thanckes and to the support the depot provides to Navy Command and other approved customers at Devonport.
The existing Yonderberry Jetty was constructed in the 1950’s. The existing structures are shown in Drawing 2-1 and figure 2.1 below shows an aerial view of the Yonderberry Jetty. The jetty is 290m long in total, comprising a 230m long approach and 60m long jetty head. The approach jetty is constructed of reinforced concrete piles supporting reinforced concrete transverse beams and deck slabs. A pipe rack housing fuel and hazardous oily waste (known as sullage) pipelines runs in parallel alongside a 2.6m wide walkway. The jetty head is constructed of a 1m deep concrete deck slab supported by 20 vertical steel box piles.
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Figure 2-1 Aerial view of the Yonderberry Jetty
2.2 Need For The Project
The provision of fuels and waste disposal services is a fundamental requirement of the Royal Navy and other customers operating within the HMNB Devonport. Without access to the storage facilities available within Thanckes OFD effective bulk fuelling and hazardous oily waste operations at Devonport could not take place. There is no alternative fuelling or sullage waste facility within the Port of Plymouth area capable of handling the volumes of product required.
In 1998, it was discovered that the steel piles supporting Yonderberry Jetty were suffering from accelerated low water corrosion. A major refurbishment was undertaken the following year in order to expand the jetty structure’s operational life for a further 10 years. During 2006/07 contractors undertaking further pile repairs had to abandon work after it was discovered that the piles were in far poorer condition than previously indicated. Since that time Yonderberry Jetty has continued to operate under strict berthing restrictions, as agreed with the Competent Authority (HSE & EA) and the Queens Harbour Master (QHM). These restrictions have a negative impact on operational efficiency of the jetty which is not sustainable.
Also due to problems encountered with the existing jetty fire-fighting system at the Thanckes OFD, the equipment is not adequate to meet the current fire-fighting requirements on Yonderberry Jetty and in the tank farm.
Therefore, it is recognised that for jetty and tank farm operations to continue long term, significant investment is required.
The resulting project objectives are:
a) To provide a loading facility suitable for ship to shore receipt and delivery of fuels, waste products and fresh water at Thanckes OFD b) To provide a site-wide fire-fighting capability for Thanckes OFD that meets current requirements c) To provide facilities with a minimum service life of 40 years that meet all current legislation and user requirements d) To comply with Ministry of Defence (MOD) policy and best practice
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2.3 Site Operations and Maintenance 2.3.1 Oil Fuel Depot Operations
Thanckes OFD and Yondberry Jetty is operational 07:30 – 16:00 Monday to Saturday with the notable exception of service to/from replenishment tankers, which are alongside for approximately 72 hours, approximately once a month.
Vessels that use the jetty to unload and load fuel are commercial product tankers, Royal Fleet Auxiliary (RFA) vessels and occasionally, although not routinely, Royal Navy warships. Currently fuel products are imported to Thanckes OFD by commercial ‘Handysize’ (approx. 35,000 tonne displacement) product tankers which vary in colour.
Fuel products are transferred to and from vessels of Royal Navy fleet and other customers within Devonport Dockyard by a fleet of lighter barges (black in colour) powered by tugs (yellow and black colour), from the pontoon at the rear of the jetty head. In addition vessels of the RFA fleet, which are grey in colour, berth at the jetty to load and unload fuel from the OFD.
The total annual occupancy for vessels alongside is approximately 30% and 60% for the main jetty and pontoon jetty respectively. There are also approximately 360 Heavy Goods Vehicles (HGVs) visiting the site per annum (Monday to Friday only), which access the site via the Main Gate at Pengelly Lane.
The operation of the tank farm, use of the loading facility (in terms of the hours of operation and frequency of use) and types of vessel that berth at the jetty are not expected to change as a result of the project. 2.3.2 Maintenance Dredging
A berth pocket is maintained adjacent to the front face of Yonderberry Jetty by a regime of routine maintenance dredging, undertaken as part of the maintenance dredging for the whole of HMNB Devonport.
Where maintenance dredging is carried out in a Natura 2000 site, the UK Government has requested that a “baseline document” is prepared to assess the activities in accordance with Article 6(3) of the European Commission (EC) Habitats Directive (92/43/EEC) (Ref 2-4). The baseline document draws on readily available information to describe current and historic patterns of dredging, in relation to the conservation objectives of adjacent European Marine Sites.
The baseline document prepared for the MOD at HMNB Devonport naval base (Ref 2-5), contains information relevant to the integrity of the Plymouth Sound and Estuaries European Marine Site, which comprises the Plymouth Sound and Estuaries SAC, the Tamar Estuaries Complex SPA and eight associated Site of Special Scientific Interest (SSSIs).
The ‘Baseline Document’ completed in 2011 states that the actual maintenance dredging quantities for the wider HMNB Devonport naval base over the past six years have averaged 72,500 tonnes per annum with a maximum in any one year of 147,904 tonnes (2004 “catch-up” at start of new term contract).
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2.4 Project Description
In July 2010 an Assessment Study was completed by Hyder Consulting (Ref 2-6), to assess options to ensure effective means of facilitating the issue and receipt of fuelling products to and from Thanckes OFD for the next 40 years. In addition works required to provide legislatively compliant fire-fighting arrangements covering the OFD tank farm and supporting infrastructure were identified. A number of options were assessed; the recommendation of the study was to proceed with Option 9 – to build a new jetty, demolish the existing (then redundant) jetty structure and to upgrade the fire fighting system.
The project would allow current operational restrictions (size of vessel, approach speed & operational wind conditions), placed by the QHM, to be revoked. The replacement jetty will be designed to accommodate vessels of up to 50,000 tonne displacement and 235m length and provide a minimum maintained dredge depth of 11.6m. This ensures current and currently projected operational requirements of the MOD for Yonderberry Jetty can be fulfilled upon completion of the project.
The new facility will be delivered by a Contractor who will be appointed to undertake the detailed design, construction and commissioning of the new jetty and then demolition of the existing jetty.
Concept designs of the new facility have been developed and are shown in Drawings 2-2 to 2-6. 2.4.1 New Jetty Structure and Berth Pocket
The proposed new loading facility will comprise of the following elements:
• New jetty head directly adjacent and to the north of the existing jetty head. The new jetty head will comprise piles supporting a new jetty deck, with new fenders to eastern face, new ladders, guard rails and lifesaving equipment. The jetty head will support new fuelling manifold and loading arms, craneage and vessel access brows. A pontoon will be provided at the rear (west side) of the new jetty head to facilitate the transfer of fuels to lighter barges and the import of sullage. Six new mooring dolphins will be constructed with walkways between each and connecting to the jetty head. A pontoon will be provided alongside one mooring dolphin to enable the safe transfer of ship’s crew to liberty vessels for transfer to HMNB Devonport.
• New jetty approach structure to the north of the existing jetty connecting the new jetty head to the shore at Thanckes OFD, comprising of piles supporting a pipe rack and walkway. It involves installation of new pipelines for fuels, fire-fighting, sullage, site drainage and potable water. The pipelines on the new jetty will be connected to the existing fuel pipelines, sullage pipeline, potable water supply, fire main, power supply, telecoms and other services located on the land close to the jetty root. The jetty approach structure will also support new personnel welfare facilities (located directly adjacent to the jetty head) and new pumps to supply water to the fire-fighting system on the jetty and for the tank farm fire-fighting system.
• Capital dredging will be required to:
a) Provide a berth pocket adjacent to the front (east) face of the new jetty head. The proposed berth pocket (300m long by 45m wide) will be maintained at a minimum maintained depth (MMD) of -11.6m Chart Datum (CD) with an approved dredge depth (ADD) of -12.2mCD. The estimated volume of sediment arising’s from the dredging of
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the berth pocket is estimated to be approximately 19,000m 3 (subject to final design calculations).
b) Provide a navigation channel to the fuel pontoon berth at the rear (west side) of the jetty head. The navigation channel will be 40m wide with a MMD of-5.0mCD and ADD of -5.6mCD. The estimated volume of sediment arisings from the dredging of the approach channel is estimated to be approximately 18,000m 3 (subject to final design calculations).
The overall facility footprint area will remain largely unchanged, except for the addition of a dredged approach channel to the rear of the jetty covering an area of 1.36ha, as indicated in Table 2-1 and shown on Drawing 1-3.
The new berth pocket is the same plan area (1.35ha) and depth as the existing berth pocket. There will be an overlap between the existing and new berth pockets of 0.92ha and, therefore, of the total new dredge pocket area (1.65ha, including the new side slopes) capital dredging is required over only 0.73ha. The remaining redundant area of the existing berth pocket will no longer be maintained. Drawing 2-7 shows the extent of the proposed relocated berth pocket and capital dredging required.
The new jetty will be 0.12ha larger than the existing Yonderberry Jetty to provide a larger working deck area to improve the safety of operations on the jetty.
Table 2-1 Existing and Proposed Development Areas Jetty Structure Berth Pocket Approach Total Area (ha) (ha) Channel (ha) (ha) Existing 0.20 1.35 - 1.55 Proposed 0.32 1.65 *1 1.36 *2 3.33
*1 includes 0.30ha of new side slopes (capital dredge only)
*2 includes 0.40ha of new side slopes (capital dredge only)
When the berth and navigation channel are being utilised an exclusion zone is required around the fuelling operation for the purposes of safety and security. The extent of the exclusion zone is indicated on Drawing 2-8. 2.4.2 Decommissioning of Existing Jetty
Firstly, all existing pipework, pumps and sumps will be drained and flushed. Then all pipelines, plant and equipment will be removed from the jetty. The existing jetty and mooring dolphins will be demolished and the piles will be cut off 300mm below the existing seabed, using floating plant and divers. It has been assumed that concrete piles would be “snipped" at the base with hydraulic shear cutters. Steel piles would be removed by either mechanical cutting or water jet cutting.
The existing bow and stern moorings and anchors will be removed.
The onshore pipelines and filterbed that are made redundant at the jetty root will be removed.
The existing berth pocket will no longer be dredged allowing it to return to its natural state thereby resulting in no significant net change in overall maintenance dredge volume. Drawing 2-7 shows the extent of the proposed relocated berth pocket.
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2.4.3 Fire Fighting Upgrade
Currently there are nine concrete lined moats throughout the site that are designed to capture any major spillage from the AVCAT, diesel and sullage tanks and contain it on site. The moat capacities and the tanks served by each moat are listed in the table below.
Table 2-2: Moat Uses and Capacities
Moat String Tanks Covered Capacity (m3)
E & F Nil - Moats not maintained 10000 G, H, I & J T13, T14, T15, T16, T18 58000 K, L & M T-25, T-26, T-27, T-28 49600
The site also currently contains several Oil Water Separators (OWSs) that act as interceptors to prevent oil from being discharged from site to the Hamoaze. All OWSs are fitted with oil in water detectors and alarms.
The separators are of a simple under and over type which retain oil in the chamber. Apart from OWS J and M, these separators are normally open as described in Table 2-3, below and can be manually closed on the detection of oil by the OWS alarm system.
Table 2-3: Separator Function and Operation Separator Serving Opening Status
Wilcove Storm water Permanent N Semi-buried tanks Permanent Primrose Legacy separator Permanent J Moats G, H, I and J During working hours M Moats K, L, M During working hours Jetty car park Roadway storm water Permanent AVCAT * AVCAT Loading Bay Permanent
*Note that this separator will become redundant on completion of the new AVCAT road loading bay There are also six foam stores [film-forming fluoroprotein (FFFP)] currently distributed around the site, with a total minimum stock of 18000 litres, for use by the emergency services.
New fire-fighting facilities will be provided on the new jetty. Fire-fighting water for the jetty and tank farm will be supplied by new submersible pumps suspended in the river from the new jetty. Screens will cover the inlets to prevent fish and debris entering the pumps and firemain. A new fire main with hydrants will be installed along the length of the jetty approach structure.
At the jetty head there will be a sprinkler system to provide a protected escape route. Two remotely controllable elevated fire monitors will be provided on the jetty head for fighting a fire from a safe position. The monitors will be individually controllable and able to discharge a spray or jet of water or non-aspirated foam.
Sufficient foam concentrate will be stored in a bunded bulk tank close to the jetty root and pumped out to the foam proportionators as required. The fire monitors and foam will be controlled from a kiosk at the jetty root where the operators will also be able to use the Closed Circuit Television (CCTV) system to see the jetty head.
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Foam concentrate will only be used in conjunction with the sea-water system on the jetty itself. Foam will not be used within the system for the tank farm but may be used as supplied together with portable foam monitors available on site. It is proposed that the foam will be a 6% FFFP, in compliance with current MOD health and safety standards. FFFP is already approved for use within the existing tank-farm and is a foam which is bio-degradable and contains natural proteins. Protein foams flow and spread slower than synthetic foams, but provide a foam blanket that is more heat- resistant and more durable. An annual plan of exercises to be held is established by the Depot Manager.
A major site exercise is carried out at least every 3 years (in line with COMAH Regulations). The Fire Services visit approximately every six months. Foam will only be used to tackle fires and will not be used during physical exercises.
Within the tank farm the existing firemain will be replaced with a new firemain pipeline loop around the existing tanks, with fire hydrants at regular spacing. The new firemain will be installed above ground (typically less than one metre above ground level), supported by pipe supports and thrust blocks, along its route.
It is a project requirement that new tank drenching sprinklers will be installed on all live fuel storage tanks on the site (total of 8 tanks currently) and connected to the firemain. Due to the restrictions on working on live fuel tanks, the drenching systems will be supported by a free-standing steel frame over each tank. Drawing 2-9 shows a possible design for the tank drenching support frame. 2.5 Design Considerations 2.5.1 Flood Risk
The design of the jetty is to comply with current legislation and guidance with respect to flood risk (NPPF (Ref 2-7). In order ensure that the risk to life (of personnel working on the jetty) and risk of pollution from flooding oil sumps and trays, the jetty deck shall be higher than the predicted water levels in the Hamoaze in 60years time (allowing for predicted sea-level rise).
The current predicted 1:1 and 1:200 year still water levels for Plymouth (Devonport) are +6.16mCD and +6.68mCD respectively (Ref 2-8). Allowing for future sea-level rise over the lifetime of the structure (60yrs) in accordance with current EA guidance (Ref 2-9), surge tides, waves and freeboard, the minimum level of the landside facilities, jetty head and mooring dolphins deck shall be no lower than +8.74mCD.
This is determined based on the following figures:
• 1:200 year Still Water Level: +6.68mCD • 60 years of sea level rise to 2077 (increase of 1.045m) • 1:100 year Wave (1.03m giving a rise of 0.515m) • 500mm freeboard 2.5.2 Lighting & Noise
Adequate lighting would be provided to ensure that all ship/shore interface activities can be safely conducted during periods of darkness. Lighting levels will meet national and international standards as a minimum, including the requirements of the International Safety Guide for Oil Tankers and Terminals (ISGOTT) and to ensure the security of the facility. The lighting levels are not expected to change significantly from the existing Yonderberry Jetty operation.
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The operation of the tank farm and use of the loading facility are not expected to change as a result of the project. Therefore the noise generated by operations in the tank farm and on the loading facility is not expected to change significantly from the existing. 2.5.3 Design Life & Maintenance
The new jetty will have a design life of 60 years, with regular maintenance throughout that period. It is assumed at the end of its serviceable life the jetty will be dismantled in a similar manner to that described in Section 2.6.7. Provision will be made in its design to enable safe demolition of the structure at end of life.
Maintenance dredging will be required to maintain water depths in the berth pocket and safe navigation in the approach channel to the rear of the jetty head. Due to an improved alignment of the jetty head with the river flow, sediment accumulation in the new berth pocket is expected to be similar or less than that currently experienced. The approach channel to the rear of the jetty head does not currently require maintenance dredging. The new approach channel may require infrequent maintenance dredging, but due to the alignment of the channel with the river flow, frequency and quantity of dredging is expected to be low.
Overall, it is anticipated that the future maintenance dredging quantities and frequencies will be similar to the existing regime. The total area that will require maintenance dredging is 2.35ha which is approximately a 1% increase in overall maintenance dredge area under the current HMNB Devonport maintenance dredge regime. 2.6 Indicative Construction Method
The construction method will be developed by the appointed Contractor to suit his design, site constraints, contract programme and available plant and resources. Due to the nature of the works, specialist construction plant is required, the availability of which will dictate the design and construction method.
In order to inform EIA and consenting an indicative construction method and programme has been prepared.
A construction waste management plan (CWMP) and construction traffic management plan (CTMP) will be prepared. 2.6.1 Site Investigations
Immediately following award of contract, the Contractor may select to undertake further site investigations to inform the detailed design. The site investigations may include intrusive investigations (e.g. boreholes and trial pits) on land and within the Hamoaze. Marine boreholes would be undertaken from a jack-up barge (marine plant). 2.6.2 Site Compounds and Access
Initially the construction of the new jetty will be undertaken from marine plant. A commercial wharf will be used for receipt and transfer of materials and plant to working barges for transport to the construction site. All materials for the construction of the approach jetty, jetty head and mooring dolphins (e.g. piles, pre-cast concrete deck sections, warren trusses and walkways) will be transported to the site from the commercial wharf. Some larger materials and pre-fabricated elements are likely to be delivered to the wharf by ship, others may be delivered by road.
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The location of the commercial wharf has not been selected, however it is likely to be within Port of Plymouth (e.g. Cattewater), where there is a choice of commercial wharfs and yards.
A mixture of jack-up barges and floating barges are likely to be used at the site as a platform for construction of the jetty (piling, walkways, dolphin and jetty deck construction). Welfare and office facilities will be provided on the working platform, as well as at the wharf. The Contractor’s staff will be transferred on shift rotations to the working platform from the commercial wharf or another convenient landing stage.
A site compound will be established within Thanckes OFD for use by the Contractor and the Client’s Representative with administration and welfare facilities and materials storage.
It will be situated on an area of land between Tank 6 & the Tank row 15 – 18 (see Fig 2-2). This compound will be used to store materials for construction of the new firefighting system in the tank farm. In addition a working area will need to be established for materials storage and construction of all land based elements of the new loading facility, including pipework and buildings in the jetty root area and for installation of infrastructure on the jetty deck. This will be located in the existing crew car park area, adjacent to the new Yonderberry Jetty root (see Fig 2-3).
Access to the compound will be from an existing surfaced access track through the Thanckes OFD tank farm, via the main entry security gate on Pengelly Road (approximately 80m from the A374 trunk road).
Only once the jetty head and approach jetty structures are complete, will there be physical connection between the marine construction works and the land-based construction at Thanckes OFD. Whilst installing infrastructure on the jetty (e.g. pipelines and manifolds, fire-fighting systems, the jetty welfare building, mooring equipment and fenders) it is anticipated that the majority of materials and prefabricated elements will be delivered by barge and lifted on to the jetty head. Other smaller deliveries may be made by road through the Thanckes OFD site.
During the demolition of the existing jetty, initial removal of plant and equipment is likely to be exported by barge to a commercial wharf or broken down for transport by road through the Thanckes OFD site. The demolition of the jetty and mooring dolphin structures will be undertaken from marine plant and exported by barge to a commercial wharf for disposal or recycling. 2.6.3 Phasing of Construction Works
The fuelling operations on the existing jetty are intended to continue until the new jetty is constructed and commissioned. However the close proximity of the new and existing jetty structures will require the construction works to be phased to enable continuity of service. This will entail parts of the existing structure being demolished prior to construction of parts of the new structure, which will result in a reduced capability of the facility during some periods of the construction programme.
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Fig.2-2 Contractor’s Compound
Electrical Feeder Column for Contractor’s Compound Jetty Access Road
115 m
40m 20m
110m CONTRACTOR’S COMPOUND
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Fig.2-3 Contractor’s Working Area: Jetty Head
Compound 20m Access Road
40m
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2.6.4 Plant and equipment
It is expected that the construction and demolition works will require the following plant:
• Jack-up barges with attendant workboats • Floating self-powered and dumb barges with tugs • Piling rigs mounted on jack-up barges • Land-based piling rigs • Floating and land-based cranes • Concrete mix and batch plant • Pipeline assembly line • Trailer Suction Hopper Dredger (TSHD) / Cutter Suction / Backhoe
• General land-based plant including excavators, dumpers, cranes, cutting and drilling equipment and temporary diesel generators.
The final choice of equipment and plant will reside with the contractor appointed to construct the works. 2.6.5 Construction Activities
The following construction activities are anticipated:
Jetty Approach Structure i. Procure and prepare tubular steel piles with protective coatings at the commercial wharf. ii. Mobilise and position the piling rig on a jack-up barge. iii. Drive piles into seabed from the jack-up barge. iv. Bore out seabed material, side-cast arisings and drive piles until socketed into competent material. v. Fabricate pile caps, crossbeams and warren trusses. vi. Lift and fix in place pre-cast concrete or steel pile caps and crossbeams. vii. Lift and install coated steel ‘Warren’ truss units to span between pile cross-beams. viii. Lift and install platforms for fire-fighting pumps and welfare & office facilities ix. Lift and install pre-fabricated welfare & office facilities and septic tank. x. Install cathodic protection system. Throughout the construction period piles and pre-fabricated structural elements will be transported from the commercial wharf to site by barge, as required.
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Jetty Head i. Procure and prepare tubular steel piles with protective coatings at the commercial wharf. ii. Mobilise and position the piling rig on a jack-up barge. iii. Drive jetty head piles into seabed from the jack-up barge. iv. Bore out seabed material, side cast arisings and drive piles until socketed into competent material. v. Lift and fix in place pre-cast concrete or steel pile caps and crossbeams. vi. Cast in-situ reinforced concrete deck and ducting. vii. Cast in fixings for equipment to be placed on the deck. viii. Fix new guardrails to the deck. ix. Drive piles for the refuelling mooring pontoon guide piles, vessel impact barrier and fendering. x. Install cathodic protection system. xi. Fix 1no. linkspan (refuelling pontoon), new fenders, quick release hooks and mooring bollards to new jetty head. xii. Install new crew access pontoon and brow. Jetty Infrastructure i. Procure and deliver pipeline lengths to Thanckes OFD site compound. ii. Fix pipe rack to the approach deck. Install all pipes and cables onto the rack. Weld pipe lengths at the jetty root and pull the welded pipeline along the approach jetty length. iii. Install the new manifold (including bund), valves, platforms, controls, sampling points, and pipe work. iv. Lift and fix new fire monitors, towers and hydrants, telescopic crane, marine loading arms, hose rack and ship access tower with staircase, working area lighting, approach speed lasers & indicators, navigation lighting, CCTV and spares/equipment store. v. Install all cabling and commission equipment. Mooring Dolphins i. Procure and prepare tubular steel piles with protective coatings at the commercial wharf. ii. Mobilise and position the piling rig on a jack-up barge. iii. Drive mooring dolphin piles into seabed from the jack-up barge. iv. Drive piles for the 1no. crew access mooring pontoon guide piles. v. Bore out seabed material, side cast arisings and drive piles until socketed into competent material. vi. Fix pile cap temporary works and cast in-situ concrete pile caps. vii. Drive walkway support piles. viii. Lift and install pre-fabricated walkways between dolphins. ix. Fix 1no. linkspan (crew access pontoon), guardrails, rubbing strips, lighting and rigger shelters to the deck x. Install cathodic protection system. xi. Fix quick release hook to each mooring dolphin xii. Install all cabling and commission equipment.
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Berth Pocket & Northern Approach Channel i. Capital dredge the new berth pocket (extension of the existing berth pocket) and northern approach channel using a TSHD or barge mounted backacter (for dense materials). ii. Transport and dispose of dredgings at Rame Head licensed disposal site by hopper dredger or split-bottom barge. iii. Level the dredged seabed with a plough / bed leveller.
Tank Farm Fire Fighting System ii. Excavate and dispose material off-site for the new foundations for pipe support plinths, road crossings culverts and tank drenching frame foundations. iii. Construct pipe support plinths along new fire main route. iv. Construct culverts at locations where the firemain crosses site roads and access tracks. v. Install new firemain throughout the tank farm site vi. Install diesel pump at Emergency Water Supply tank (Tank 7) vii. Install new pump control building, new standby generator, new electrical feeder pillar, new foam storage and proportioner building and new firefighting control kiosk in Jetty Root area viii. Install new tank drenching sprinklers and support frames over 8 live fuel storage tanks on the site 2.6.6 Piling Method
The anticipated piling methodology will be as follows:
i. Initially press the casing through the soft sediments until firm ground is encountered. ii. Drill inside the casing and oscillate and tap the casing through the firm ground/weathered slate until hard ground is encountered. This may require limited hammering, however; the majority will be achieved by oscillating the casing in. iii. Either drill through hard ground to form a pile bore into which steel reinforcing is placed and concreted or drill out and drive the casing as above to the required depth in the hard bedrock. This may require some hammering, however; the majority of the depth will be achieved through drilling and oscillating the steel casing into the bedrock. iv. All sediment/soil/rock within the casing will be drilled out. v. The arisings from the drilling are likely to be relatively fine grained. vi. All pile arisings will be deposited around sub-tidal piles only. As a result, piles will be within a casing, either down into strong rock, or down to weathered rock with a column drilled below into strong rock to provide a rock socket. 2.6.7 Demolition Method
The anticipated method of demolition of the existing facility will be as follows:
i. Empty and flush all fuel and sullage pipelines. ii. Remove all equipment, buildings, tanks, pipework, etc. from the jetty head to barges for transport to commercial wharf for disposal/re-cycling. iii. Remove all pipelines, cables, ducting and pipe supports from the approach jetty to barges for transport to commercial wharf for disposal/re-cycling.
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iv. Demolish and dispose/re-cycle the redundant buildings and pipework on the land at the jetty root. v. Demolish the existing jetty head, approach structure and mooring dolphins by cutting and breaking out the concrete deck and beam elements, using floating plant. vi. Piles to be cut-off 300mm below final seabed level, using floating plant and remotely operated vehicles (ROVs) or divers. vii. Dispose of all materials by appropriate recycle or disposal method. Measures are to be put in place to contain all demolition material and prevent waste materials falling onto the seabed or polluting the watercourse.
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2.7 Project Programme
Key planning and indicative project milestones for the project (assuming necessary consents are obtained) are set out in Table 2-4:
Table 2-4: Key planning and project milestones
Milestone Assured programme
Undertake EIA December 2012 – November 2014
Submit planning & marine licence (construction) May 2015 applications. The EIA will be contained within the ES will accompany the submission.
Local Planning Authority (LPA) statutory 28 days consultation period
MMO statutory consultation period 42 days
Obtain all statutory consents September 2015
Construction contract award Autumn 2016
Design and planning period Autumn 2016 – Spring 2017
Construction period 2017–2019
Handover of new jetty 2019
Demolition of existing jetty complete 2019
Assuming that all necessary consents are obtained and the design and construction contract is awarded by Autumn 2016, it is anticipated that construction mobilisation will commence in early 2017 and works would commence in Spring 2017.
Consultation has been undertaken with Statutory Consultees with regard to seasonal restrictions of piling activities. These restrictions are detailed below as per Natural England email dated 2nd May 2014 (Appendix 2A):
• Non-percussive piling (i.e. vibro-piling, pile case oscillation and auguring/drilling) would be possible at any time of year, provided that monitoring of noise levels is undertaken for the first four piling events and comparing these to the predicted levels (see Subacoustech paper in Appendix 2A), before carrying out these activities during the 1 April – 31 August key sensitive period.
• Percussive piling is to be restricted to the months of September to March, inclusive, to minimise the impact on fish migration in the Tamar River. This constraint will mean that multiple piling rigs may be required to work concurrently to enable the construction of the new jetty head, approach jetty and mooring dolphins within the project programme. Due to the proximity of the works to residential areas (Torpoint and Wilcove), it is anticipated that construction works will generally be undertaken during normal working hours (Monday – Friday between the hours of 0800 to 1800 and Saturdays 0800 to 1300). It may be necessary to undertake some works, including dredging activities and movement of barges/plant, outside these times due to tidal constraints.
Construction and commissioning is programmed to be complete by early 2019. The demolition works will be phased with the construction works, to enable the tank farm to continue to operate
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throughout the construction and demolition periods. Demolition works will be complete by Autumn 2019. 2.8 Alternatives Considered
This section summarises the main alternatives considered during the development of the scheme and reasons why alternative proposals have been discounted. This considers the evolution of the proposal from the Assessment Study to Concept Design stage, including the recently revised location of the proposed jetty structure. 2.8.1 Assessment Study
An Assessment Study was commissioned by Defence Estates in 2009, which evaluated a number of options to provide a fuel loading facility and fire fighting upgrade at Thanckes OFD. To ensure that all potential options were considered at the commencement of the assessment study, a Brainstorming Workshop was held at HMNB Devonport on 4 September 2009. This workshop derived 26 potential ideas for provision of a loading facility and fire main upgrade at Thanckes OFD. Those ideas that clearly did not satisfy the requirements of the User Requirement Document (URD) were discounted.
Further work was then undertaken to assess in detail the remaining options and reported in the Initial Options Appraisal Report dated 15 January 2010 (Ref 2-10). The Options Appraisal Report identified 14 options that were further evaluated before the Decision Conference held on 24 November 2009. The Decision Conference identified the 6 options that were subsequently assessed during the Assessment Study. The 6 options considered were:
° Option 4 - Refurbish Approach and Jetty ° Option 6 – Refurbish Approach and new build Jetty Head north of Existing ° Option 7 – Build new approach and refurbish Jetty Head ° Option 8 – Refurbish Approach and Jetty Head and provide new floating platform ° Option 9 – New-build Approach and New-build Jetty Head ° Option 14 – Build new Approach and floating Jetty Head An initial Environmental Appraisal and sustainability appraisal (SA) was undertaken for all options as part of the Assessment Study. The findings of these appraisals are summarised below in Table 2-5 as environmental and sustainability considerations for each option. These considerations informed the principal conclusions from the Assessment Study (Section 2.8.2).
Table 2-5 Environmental and sustainability considerations Option Environmental Considerations Sustainability Considerations
Option 4 - Option 4 causes less environment impact during Option 4 has only limited Refurbish Approach construction than some of the other new build negative sustainability and Jetty Head options, as the option makes use of large impacts due to limited short- elements of the existing footprint. No dredging is term construction period. required for this option. The option is not expected to give rise to need for material mitigations or difficulties with permitting, but further EIA fieldwork is likely to be necessary.
Option 6 – Option 6 involves less environment impact Option 6 has only limited
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Refurbish Approach during construction than some of the other new negative sustainability and new build Jetty build options as the option makes use of the impacts due to limited short- Head north of existing approach footprint. Dredging is required term construction period, Existing for this option as there is a need to extend the although any dredging works dredged box northwards, although this is to the north of the existing mitigated because a similar area at the southern dredge box will require careful end of the dredged box would be released from consideration. any need to dredge in the future. The Option is not expected to give rise to need for material mitigations or difficulties with permitting, but a further EIA fieldwork is likely to be necessary.
Option 7 – Build Option 7 involves greater environmental impact Option 7 has only limited negative sustainability impacts new approach and during construction than some of the other new due to limited short-term refurbish Jetty refurbishment options, as the option requires a construction period. Head new approach. However dredging is not required for this option. The option is not expected to give rise to need for material mitigations or difficulties with permitting, but a further EIA fieldwork is likely to be necessary.
Option 8 – Option 8 involves less environment impact Option 8 has only limited Refurbish Approach during construction than some of the other new negative sustainability and Jetty Head and build options, as the option makes use of the impacts due to limited short- provide new existing Head footprint. A small amount of term construction period. floating platform dredging is required as the dredge box protrudes further into the river than at present. The option is not expected to give rise to need for material mitigations or difficulties with permitting, but a further EIA fieldwork is likely to be necessary.
Option 9 – New- Option 9 involves more environment impact build Approach and during construction than some of the other New-build Jetty refurbishment options, as the option requires a Head permanent new build Jetty in a new location. Capital dredging is required for this option as the works would require the creation of a new dredge box. Maintenance dredging would also be required.
Option 14 – Build Option 14 involves a moderate environment Option 14 has only limited new Approach and impact during construction as dredging of a new negative sustainability floating Jetty Head dredge box is required. This however will be impacts due to limited short- offset by the abandonment of the dredge box to term construction period. the south. The option is not expected to give rise to need for material mitigations or difficulties with permitting, but a further EIA fieldwork is likely to be necessary.
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2.8.2 Principal Conclusions Of The Assessment Study
The detailed findings of the study are given in the respective sections of this report. Principal conclusions from the study were as follows:
• The “Do Nothing” is not viable given continuing deterioration of the jetty and the threat of its closure on safety grounds. Closure of the facility would severely inhibit Navy Command and other customers operating within the HMNB Devonport.
• A loading facility compliant with the URD can be provided by each of the appraised options (Options 4, 6, 7, 8, 9 & 14) at Thanckes OFD.
• Options involving re-use of existing jetty piles (Options 4, 6, 7 & 8) provide the least environmental impact but carry the highest risk in terms of future capacity of the facility. Besides the impacts of estimated cost and programme risk identified for these options, it is likely that a contractor would not accept the design liability associated with the existing piles in which case the MOD would retain this significant risk. Post-project loading facility outages are likely for further pile maintenance. Retention of this risk would blur responsibilities should defects occur after completion and acceptance of the works.
• Fire-fighting facilities in compliance with the URD can be provided to both the tank farm and loading facility via solutions that are essentially the same across all appraised options. Salt water fire-fighting systems are considered to offer the best value for money solution given the physical constraints at the site and for compatibility with existing Aquatrine Contract arrangements.
• All appraised options are located within a European designated SAC and require statutory marine consents. Subject to formal confirmation from the Local Planning Authority during the future Develop Preferred Option stage of the project, all options shall require a statutory Environmental Impact Assessment.
• Option 9 provides the optimum URD compliant option that provides the most cost effective and operationally effective solution, taking into account through life cost.
Option 9 – ‘New build jetty approach and head’ was recommended as the preferred option. 2.8.3 Location Of Option 9
The Assessment Study (Section 2.8.1) was completed in July 2010, at the time it was concluded that Option 9 provided the optimum URD compliant option. During the Assessment Study there was no evidence to identify contamination of the riverbed sediments and therefore it was assumed that all dredged material could be disposed at the offshore licensed disposal site at Rame Head. However, subsequent chemical analysis of the sediments within the northern end of the proposed dredge area identified that some sediments contain substances that are elevated above Centre for Environment Fisheries and Aquaculture Science (Cefas) Action Level 2 whereby disposal at sea is not permitted.
At present there is no restriction on the disposal at sea from the existing Yonderberry Jetty dredge box which has been in place during the last 10 years of maintenance dredging. Sampling and testing are required as part of the regulatory consent process for maintenance dredging.
A workshop was undertaken on 11th March 2014 which brought together specialists to investigate the options for dealing with the contaminated sediments and alternative jetty
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locations to mitigate or avoid the associated issues. Four alternative locations for Option 9 were identified:
• Location 1 – Build new Approach and Jetty Head on the footprint proposed at Assessment Study stage (including contaminated sediment treatment and disposal) • Location 2 – Build new Approach and Jetty Head on existing jetty footprint • Location 3 – Build new Approach and Jetty Head in front of existing jetty head • Location 4 – Build new Approach and Jetty Head 170m south of Location 1 A Position Paper presents the findings of a high-level options appraisal to assess potential solutions for dealing with contaminated sediment which has been discovered in the Tamar and which will affect delivery of this project. The paper presents the advantages and disadvantages of each option.
Locations 1 & 4 offer unhindered business continuity throughout the construction period. However, Locations 2 & 3 requires the operator to make provision for alternative fuelling arrangements for all or part of the construction period.
Location 1 carries a number of significant project risks connected with the capital dredging, treatment and disposal of contaminated sediment (e.g. Waste Permits, Discharge Licence) that are significantly greater than those of Locations 2 - 4 and which have not yet been quantitatively assessed. Future maintenance dredging risks may be mitigated by over dredging a Buffer Zone.
Location 4 was the recommended option as it has the lowest estimated capital cost, low delivery risks and enables business continuity throughout the construction period. Drawing 2-10 shows Location 4 has subsequently been formally endorsed by DIO. This ES is therefore based on Option 9 Location 4. 2.8.4 Alternative Disposal Site Options
There is a requirement to dredge and dispose of approximately 37,000m 3 of material from the seabed for this project. The Assessment Study identified the licensed offshore disposal site at Rame Head to provide the most sustainable disposal option for uncontaminated dredged material.
Since the Assessment Study, alternative disposal options have been assessed. The disposal for the dredge arising’s was discussed with Statutory Consultees at the EIA Assessment of Effects meeting on 24 th September 2014. At that time no other projects or schemes were identified which could provide an alternative use for dredge arising’s.
Subsequently investigations identified alternative disposal options as discussed below:
• Ernesettle Trots Dispose of dredged material in the previously maintained dredge box at Ernesettle Trot moorings, which were abandoned in 2005. However further investigation has found that material has subsequently accreted at this location, providing insufficient capacity for receipt of additional material from the Thanckes project.
• RAFT Project Site Dispose of dredged material in the area previously dredged for the RAFT Project in 2001. However further investigation has found that the hydrodynamics at this site have maintained levels at this location since the dredging was undertaken. It is observed, therefore, that the “energy state” in this area is high and any material placed in this location is likely to be unstable. The sea bed shear stresses are such that any material
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deposited in this area is likely to be released into suspension in the water column, increasing turbidity and distributing the material, for all but the heaviest grading sizes, elsewhere in the estuary.
• High Water Bird Roost Improvements Improvement of existing high water roosts and creation of new roosts from the proposed dredged material have been considered. A potential site has been identified at Sango Island in St John’s Lake, south of Torpoint. A high level review of the material type, material quantity, placement method and programme of the works indicate that the work would be difficult to undertake in shallow water and are likely to cause significant disruption and environmental impact to the heavily designated (SSSI and SAC) site. Therefore this option is unlikely to achieve consent.
• Onshore Disposal Waste management companies who operate waste treatment and disposal facilities in the local area have been consulted. There are three locations identified within Devon and Cornwall where dredge arisings may be accepted and used for restoration purposes. However, the sediment dredged straight from the river would have to be sufficiently de-watered and dried before it could be transported and before it would be acceptable to be received by these sites. No suitable site has been identified for landing and dewatering the dredged material in its “wet” state. If a site can be found it would require a considerable logistical and economical challenge and it is considered that the environmental impact of the treatment and transport process would outweigh the benefit of avoiding disposal at sea.
The investigation of the alternative disposal options has found that none of the alternative options are feasible.
Since the volume of capital dredging and disposal is relatively small in the context of the volume of maintenance dredgings disposed at the licensed offshore disposal site at Rame Head, the investigation has concluded that disposal at the Rame Head licensed disposal site is the most sustainable option for the Thanckes OFD project. The ES has been progressed on this basis.
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3 ENVIRONMENTAL IMPACT ASSESSMENT METHODOLOGY 3.1 Introduction
The ES presents the assessment of the significant environmental effects likely to result from the construction, operation and decommissioning of the Development. This chapter sets out the various stages of the EIA and the approach used to assess impacts. 3.2 Legislation and Guidance
Each chapter contains a summary of the relevant regional, national and international legislation and policies. In addition, each topic includes details of relevant technical guidance which has been followed. 3.3 Scoping of Environmental Topics 3.3.1 Screening and Scoping
In accordance with Regulation 5 and 13 of the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 a request for screening and scoping opinion was submitted to CC on 17 th November 2012 (Appendix 1-B).
In accordance with Regulation11 and 13 of the Marine Works (Environmental Impact Assessment) Regulations 2007, as amended 2011; a request for screening and scoping opinion was submitted to MMO on 17 th November 2012 (Appendix 1-B).
A scoping report (Appendix 1-C) accompanied the request. This identified that the Development could potentially have significant environmental effects on the following topic areas:
• Water Quality, Sediment Quality, Geology & Contamination
• Ecology – Marine
• Ecology – Terrestrial
• Archaeology & Culture Heritage
• Noise & Vibration
The following areas were scoped out of the scoping report; the scoping opinion on these points is covered in 3.3.3.
Flood Risk & Hydrology No significant increase in flood risk is predicted to arise as a result of the construction, operational and demolition phases of the project. Flood Risk & Hydrology were scoped out of the EIA, although a separate Flood Risk Assessment (FRA) was proposed to accompany the planning application.
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Traffic & Transport (including Navigation) Some disruption to existing fuelling operations but effects would only be temporary. An increase in construction traffic comprising heavy vehicles and site visits by road by contractors and supervisory staff would be temporary during the construction phase. No impact on navigation channels predicted during construction, operation or decommissioning. A transport assessment may be required for the planning application.
Air Quality No significant or measurable increase in air pollution is predicted to arise as a result of the construction, operational and decommissioning phase.
Human Environment Due to the location of the project, there are unlikely to be significant effects on Public Rights of Way (PRoW) during the construction and demolition phase. As the proposed jetty will replace the existing jetty no significant effects are anticipated during the operational phase.
Landscape and Visual No adverse impacts on Lynher and Tiddy River Valleys Landscape Character Area (LCA) and Tamar Valley AONB for the construction, operational and decommissioning phase. The new position of the jetty is likely to lead to minor beneficial impacts on views for properties located on Albion Road in Torpoint. For some properties in and around the coastline settlement of Wilcove impacts are likely to be minor adverse.
Overall, the landscape around the site is considered to have a low sensitivity to the type of change proposed during construction and as such any impacts arising from it would most likely not be significant.
A full assessment of landscape and visual was not considered necessary given the existing context of the site and presence of the existing jetty. Therefore an assessment of impact on views from properties within Wilcove may be necessary to support the planning application.
Hydrodynamics As the new jetty does not interrupt the flow to any greater degree than the existing jetty it is considered unnecessary in this instance to undertake hydrodynamic modelling of river flows. Therefore, for the reason stated above it is not proposed to consider hydrodynamics further in the EIA for the project. 3.3.2 Scoping opinions
Scoping opinions were received from CC (Appendix 1-E) and the MMO (Appendix 1-F) by Hyder on 1 March 2013 and 27 March 2013 respectively. As a result of which clarification were required for the following.
Hydrodynamics MMO requested a more detailed justification for the scope out of hydrodynamics be included within this ES. A Technical Note on hydrodynamics in the vicinity of the proposed new jetty has been prepared and is included within Appendix 3A. This note also addresses the addition of the navigation channel.
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Flood Risk Assessment CC agreed that a FRA was not required as part of the EIA, but that one would be required to support the planning application.
Traffic & Transport CC Agreed that traffic and transport does not need to be included within the EIA, however a full Transport Assessment should be included with any formal submission which should include details of deliveries and works machinery and transportation of waste etc.
During The Thanckes OFD assessment of effects workshop 24 th September 2013, the inclusion of a formal Transport Assessment was discussed and deemed as not to be required. It was proposed that the Contractor provides a Construction Travel Plan/Traffic Management Plan prior to the start of construction. This approach has been confirmed as acceptable by CC 16 th October 2014 as the transport during operation would remain the same.
Landscape and Visual CC confirmed that a landscape assessment should be included within this ES considering the visual impact upon the landscape /nearest properties and nearby historic parks and gardens.
Air Quality CC agreed that air quality does not need to be included within the EIA and that a reference should be made within the formal application. CC confirmed on 4 th November 2014 that an air quality assessment is not required to support the planning application and that an acknowledgement of this is contained within the Planning Statement. 3.3.3 Revision to location of Jetty and inclusion of tank farm firefighting upgrade
Due to the iterative nature of the design process there has been a revision to the location of the Jetty and the inclusion of the tank farm fire fighting update, since receipt of the MMO and CC scoping opinions. The project description is provided Section 2.4, with Section 2.9.3 covering in detail the reasons for the location change. As a result of these design changes the statutory consultees were provided with an update letter and supporting drawings on 29 th October 2014, these are included within Appendix 3B). 3.3.4 Scope of this Environmental Statement
In accordance with above, the responses received and subsequent discussions with consultees, the scope of this EIA includes:
° Water Quality, Sediment Quality, Geology & Contamination ° Marine & Terrestrial Ecology ° Archaeology & Cultural Heritage ° Noise & Vibration ° Landscape & Visual
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3.4 Environmental Impact Assessment General Methodology
In accordance with relevant guidelines, the EIA has incorporated the following elements:
The Baseline: Baseline environmental conditions, including those that are predicted to exist immediately prior to construction and operation of the development as well as those currently existing, have been identified through a number of means. They were determined through consultation, the use of existing data or through undertaking additional surveys, studies and modelling. Each environmental discipline has identified key resources and receptors that have been taken into account during the assessment process.
Spatial Scope: The area over which impacts could potentially occur is wider than the area of land directly taken by the proposals. It is inappropriate to define a single study area for the assessment, since the spatial scope varies depending on the topic under consideration. Spatial scope is described within each chapter.
Temporal Scope: In considering the environmental effects of the development, it is necessary to identify impacts that may occur during construction, operation and decommissioning of the existing and proposed jetty
Construction extends from the commencement of site works to the date immediately prior to opening of the development.
Operation extends from immediately after opening of the first phase of the development for the remainder of its life.
Iterative Assessment and Mitigation Design: Impacts associated with the construction, operational and decommissioning stages of the proposed development have been identified during the course of the EIA process as the design has evolved. The approach to mitigation has been based on the mitigation hierarchy of avoidance, reduction and compensation. These are described in each assessment chapter as relevant, and represent the basis of the assessments of residual impacts in this ES.
Assessing Impacts: Impacts associated with the construction and operational stages of the Development have been identified. These have been considered in terms of their nature, the physical extent of their influence and the magnitude of their effects. In considering the nature and significance of the impacts, the effects were assessed on the basis of whether they would be:
• Direct or indirect
• Temporary, short, medium or long term
• Reversible or irreversible
• Beneficial or adverse
• Cumulative
Qualitative and quantitative techniques have been used to assess these impacts, as appropriate. The EIA identifies those elements of the development that have been introduced to mitigate potential adverse effects and assesses the significance of the impacts that remain after mitigation measures have been put in place (the “residual impacts”).
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Determining Significance : Determining whether or not an effect is significant, is an important step in the formal EIA process, and is necessary in order to satisfy statutory reporting requirements. In general, the significance of an impact reflects the importance or value of the affected resource or receptor, its sensitivity to change, and the magnitude of the predicted impact. The criteria for determining significance varies from topic to topic but the general principle that has been followed is that higher magnitude impacts on important resources would be regarded as significant. Lower magnitude impacts on less important resources would not generally be regarded as significant.
The principles of the assessment matrix shown in Table 3-1 have been followed to determine impact significance for this EIA. Topic specific assessment will be based on Table 3-1, but may differ depending on specific methodologies used.
Table 3-1 Determining significance
Importance/sensitivity of resource or receptor
Magnitude of potential Very High High Medium Low Negligible impact
Very Large Large or Very Moderate or Slight or Slight Major Large Large Moderate
Large or Very Moderate or Moderate Slight Neutral or Moderate Large Large Slight
Moderate or Slight or Slight Neutral or Neutral or Minor Large Moderate Slight Slight
Slight Slight Neutral or Neutral or Neutral Negligible Slight Slight
No Change Neutral Neutral Neutral Neutral Neutral
The importance/sensitivity of resource or receptor has been determined through the baseline studies, and each discipline sets out their criteria for this.
The terms “impact” and “effect” are used interchangeably throughout this ES. 3.5 Consultation
Extensive consultation was undertaken as part of the previous assessment study (Section 2.8.1), a summary of which is available in Appendix 3-C along with copies of responses received from primary advisors and consultees.
Statutory and key non-statutory consultees have been involved during project development and this has continued throughout the EIA process (both as a part of the scoping process and during ES preparation). A full log of consultations undertaken as part of the EIA process is included in Appendix 3-D.
Consultations with regard to the project have been carried out in accordance with MMO Marine Licencing Guidance, as shown in Appendix 3-E, The Town and Country Planning (Development Management Procedure) (England) (Amendment) Order 2013 (ref 3-1) and CC's Statement of Community Involvement (ref 3-2). The following have been consulted during the EIA process:
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Cornwall Council Cornwall Wildlife Trust (CWT)
Marine Management Organisation British Trust for Ornithology (BTO)
Queens Harbour Master Environmental Records Centre for Cornwall and the Isles of Scilly The Duchy of Cornwall Cornwall Bird Watching & Plymouth Council Preservation Society
Tamar Esturies Consultive Forum Oil and Pipeline Agency
Natural England The Crown Estate
Environment Agency Maritime and Coastguard Agency (MCA) Centre for Environment Fisheries and Aquaculture (Cefas) Cornwall Council Historic Environment Service
3.5.1 Statutory body and stakeholder consultation
Prior to the submission of the scoping report to the consenting authorities, consultations were held with a number of statutory consultees. An external stakeholder consultation workshop was held on 15 th November 2012 at Thanckes OFD, where the draft scoping report (issued on 6 th November 2012) was discussed. The following consultees were present at the workshop:
• Cornwall Council • Marine Management Organisation • Queens Harbour Master Plymouth • Plymouth City Council • Natural England • Environment Agency • Tamar Estuaries Consultative Forum
The workshop gave the consultees an overview of the project and the proposed approach to the EIA. Minutes of the workshop are provided in Appendix 3-F.
Furthermore an assessment of effects workshop took place on 24 th September 2013, the minutes of which are available in Appendix 3-G. This workshop covered discussions with regard to the draft ES chapters.
In addition consultation has been undertaken with regard to underwater noise and fish migration. Two consultation meetings took place on 14 th November 2013 and 8 th January 2014, meeting minutes are contained within Appendix 3H. Ongoing discussions in relation to this issue have resulted in the advice in respect of piling methods and restrictions due to key migratory periods of all the fish species found in the Tamar. This advice is included in section 2.7.
Topic specific stakeholder and statutory consultation is covered within each technical chapter, along with data requests.
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3.5.2 Scoping consultation
Upon submission of the scoping report to the consenting authorities, formal consultation was held, in accordance with the Town and Country Planning (EIA) Regulations (Ref 3-3) and the Marine Works EIA Regulations (Ref 3-4), by both CC and the MMO.
As part of their consultation the MMO consulted with the following organisations, a copy of these are contained within Appendix 3D
• Cefas • Natural England • Environment Agency • English Heritage • The Crown Estate • Maritime and Coast Guard Agency • Duchy of Cornwall • Plymouth City Council • Cornwall Council • Queens Harbour Master 3.5.3 Update letter
Consultation responses received from the statutory consultees state that the scoping opinions are still valid. Copies of the responses are provided in Appendix 3D. 3.5.4 Public and community consultation
A public exhibition was held on Wednesday 23 rd October 2013 at Torpoint Town Hall between 3pm and 7pm. A preview for the councillors took place the previous night (Tuesday 22 nd October 2013) between 7pm and 8.45pm. During the public exhibition the councillors and public were given the opportunity to complete a feedback form (Appendix 3I).
Proposed development at Thanckes OFD exhibition website was created https://www.gov.uk/government/publications/proposed-development-at-thanckes-oil-fuel-depot- exhibition . The information on the website included a replication of what was displayed at the public exhibition at Torpoint Town Hall on Wednesday 23 rd October 2013, and what has subsequently been displayed in local facilities following the exhibition.The website went live on 24 th October with a two week deadline for receipt of all representations.
Parish Council meetings for Torpoint and Antony Parish Council were attended on 28 th October and 7 th November 2014 respectively. An update on the Thanckes project was provided. A copy of the presentation is provided in Appendix 3J. Issues identified at the previous consultation event were discussed within the presentation and it was demonstrated how these have been addressed.
A Statement of Community Involvement accompanies the planning application, including a full summary of responses received from the public exhibition. This is to satisfy the statutory requirements as adopted in CC's Statement of Community Involvement. 3.6 Assessing Cumulative Effects
Cumulative impacts result from the incremental impacts of the project when added to other past, present and reasonably foreseeable future actions. The impacts from a single development may
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not be significant on their own but when combined with other impacts and other developments, these effects become significant.
Cumulative effects will be considered by describing and assessing the following:
• Interaction of impacts from the project with those from other plans or activities, including the various phases of the project
• Interaction of different impacts of the project, which affect the same resource or receptor.
Cumulative impacts have been considered in each topic chapter as necessary.
Other Proposed Developments At present there are three reasonably foreseeable developments within the vicinity of the proposed development that will be considered for cumulative impacts, as advised by statutory consultees and DIO. A brief description of each development is given below. Locations of these developments are shown on Drawing 3-1.
MOD Forward Operating Base at Kinterbury Point
The project proposal is the creation of a Forward Operating Base (FOB) at Kinterbury Point, within HMNB Devonport, for the Fleet Helicopter Support Unit (FHSU) which transfers naval staff to vessels.
Up to December 2011 the FHSU operations Main Operating Base (MOB) was at Plymouth City Airport with the Helicopter Landing Site at Weston Mill Lake (WML) within HMNB Devonport serving as a pick-up and drop-off point. In December 2012, following closure of Plymouth City Airport and cessation of flights at the WML HLS due to flight safety concerns, the FHSU Main Operating Base was relocated to Newquay Airport and the existing HLS at HMS Raleigh was adapted to act as a temporary FOB. A project was initiated under DIO to study possible options for providing a long-term solution for the FHSU. The maximum total number of flights in any one month would be 100, with the average being 60 (a “flight” is one take-off and one landing). The recommended option is to retain a MOB at Newquay Airport; construct a new permanent day and night capable FOB at Kinterbury Point taking approximately 70% of the FHSU aircraft movements; with the remaining 30% at a secondary FOB at HMS Raleigh.
As mitigation for the higher number of flights from the interim solution and longer-term proposals for HMS Raleigh, the MOD has committed to planting and maintenance of an improved partial screen along the foreshore at Trevol Range, to reduce cumulative disturbance to birds feeding on St John’s Lake (including non-SPA species)
MOD Refurbishment and Operation of Trevol Jetty
The MOD are currently consulting with regulators over the refurbishment and operation of Trevol Jetty at HMS Raleigh. This project will be subject to Marine License and Planning permission including in-combination assessment. There are possible very localised and very short term effects of construction on intertidal and subtidal habitats. Discussions with Natural England (NE) on the 9 th December 2013 suggest that they are of the opinion that there will be limited disturbance to overwintering birds caused by the training operations associated with the use of this jetty (approximately two operations a week) however NE have raised concerns that in combination with the temporary interim increase in helicopter activities at HMS Raleigh there will be disturbance to the bird assemblage in St Johns Lake. The MOD does not consider that operational use of the jetty is likely to cause significant disturbance to Avocet or Little Egret feeding or roosting in St John’s Lake due to the distance from the significant roosting areas and the low usage of this jetty by personnel. However, MOD has committed to plant screening along
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the shoreline in the vicinity of Trevol Jetty as a mitigation measure to reduce the overall potential cumulative disturbance to the bird assemblage feeding in St Johns Lake.
South West Devon Waste Partnership Combined Heat and Power Plant
The South West Devon Waste Partnership has contracted MVV Environment Ltd to construct a Combined Heat and Power Plant at Weston Mill Lake. Construction started in 2012 and will likely coincide with construction of the proposed FOB at Kinterbury Point.
MOD’s Devonport Landing Craft Co-location
The scoping report identified the MOD’s Devonport Landing Craft Co-location Project (DLCCP) at Weston Mill Lake as a cumulative development. This project has now been completed and is operational. Ongoing military training activity within the Tamar Estuaries Complex was assessed as part of the DLCCP EIA and Habitat Regulations Assessment (HRA) which concluded that “the extent of the training areas will not change during operation of the DLCCP, and areas within the Tamar estuary are already being used for training purposes by the two squadrons, so the frequency of use is unlikely to increase greatly. Areas for landing craft and hovercraft training have been identified avoiding some areas throughout the year, and other areas at certain sensitive times of the year. 3.7 Other Relevant Consents, Licences and Assessments
The project requires a number of consents and licences for both the construction and operational phases. It also requires assessment in relation to the Water Framework Directive (WFD) and HRA. Details are provided below:
• Planning Consent under Town & County Planning Act 1990 (Ref 3-5)
• Marine Licence (for the construction of the permanent marine structures and disposal of capital dredge material) under the Marine and Coastal Access Act 2009 (MCAA) (Ref 3- 6)
• Environmental Permit under Council Directive (2008/1/EC) Integrated Pollution Prevention & Control (Ref 3-7) as implemented through Environmental Permitting (England and Wales) Regulations 2010 (Ref 3-8)
• Water Framework Directive (WFD) Scoping under Council Directive ( 2000/60/EC) Water Framework Directive (Ref 3-9) transposed into UK law through The Water Environment (Water Framework Directive) (England and Wales) Regulations 2003 (Ref 3-10)
• Habitat Regulations Assessment (HRA) under Council Directive (92/43/EEC) Habitats Directive (Ref 3-11) transposed into UK law through the Conservation of Habitats and Species Regulations 2010 (Ref 3-12)
The abstraction of water for use in a firemain does not require a licence under Section 32(2)(a) & (b) Water Resources Act 1991 (Ref 3-13) as it is viewed as being for ‘fire-fighting purposes’ (within the meaning of the [1947 c. 41.] Fire Services Act 1947 (Ref 3-14)).
OFD Thanckes is currently a COMAH top-tier site regulated by the HSE and the EA. The controlling document is the Safety Report prepared by the operators (OPA). The current Safety Report details Safety Critical Elements and their inspection regime.
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HSE/EA will require review of documentation used to control the project: • Strategic Brief (prior to tender). • Pre-Construction Safety Report (PCSR) (during detailed design). • Pre-Operation Safety Report (POSR) (during construction). • Proposed revision to the Safety Report a full 6 months before the new facility is commissioned. Also OPA will be required to provide the EA with an environmental impact assessment 6 months prior to commissioning, coupled to the proposed Safety Report.
The Enforcing Authority for 2005 Regulatory Fire Reform Order [RR9FS)O 2005] for the site is the Crown Premises Inspection Group (CPIG) but this remains to be confirmed by CPIG. 3.7.1 Habitat Regulations Assessment (HRA)
This project requires statutory approvals from a number of public bodies which are Competent Authorities under the Habitats Regulations. At the EIA scoping workshop in Sept 2013 it was proposed and agreed that the MMO would act as the Lead Competent Authority for the HRA, and that the ES would include information to inform their assessment and decision.
Under Article 6 of the Habitats Directive (92/43/EEC) (Ref 3-11), an assessment is required where a plan or project may give rise to significant effects upon a Natura 2000 site (also known as ‘European Sites’). Natura 2000 is a network of areas designed to conserve natural habitats and species that are rare, endangered, vulnerable or endemic within the European Community. This includes SACs designated under the Habitats Directive for their habitats and/or species of European importance and SPAs classified under Directive 2009/147/EC on the Conservation of Wild Birds for rare, vulnerable and regularly occurring migratory bird species and internationally important wetlands (Ref 3-15).
Therefore, due to the proximity of Thanckes OFD to Plymouth Sounds and Estuaries SAC (Project site is within SAC boundary) and Tamar Estuaries Complex SPA (within 500m of Project site); an HRA has been undertaken, in accordance with the above. The locations of the designated sites are shown on Drawing 1-4.Chapter 6 of this ES covers the HRA. 3.7.2 Water Framework Directive Assessment
The Water Framework Directive (2000/60/EC) (Ref 3-9) came into law through the Water Environment (Water Framework Directive) (England and Wales) Regulations 2003 (Ref 3-10). The WFD was put in place to:
• Enhance the status, and prevent further deterioration of aquatic ecosystems and associated wetlands which depend on the aquatic ecosystems;
• Promote the sustainable use of water;
• Reduce pollution of water, especially by ‘priority’ and ‘priority hazardous’ substances; and,
• Ensure progressive reduction of groundwater pollution.
It set targets for all waterbodies in Europe that are classified under the WFD, requiring that they reach at least good ecological status (or potential) by 2015. This date has now been extended to 2027 on a large number of waterbodies. Around 20% of waterbodies in England and Wales are currently meeting the objective.
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In England, WFD actions are managed through the River Basin Management Plan (RBMP) process. For the proposed development, the relevant RBMP is the South West RBMP. The first plan was initially published by Environment Agency in 2009 and is currently being updated.
The WFD has important implications for planning development works. It will only allow proposals on a waterbody if they do not cause deterioration in waterbody status (and they should ideally improve the status of the waterbodies).
If a proposed development would result in an adverse effect to a waterbody that could cause deterioration in its WFD status or could prevent actions which are required to raise the WFD status of the waterbody, then the proposed development must be assessed and justified with mitigation proposed, as specified in Article 4.7 of the WFD. A WFD assessment for the project has been included in Chapter 5.
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4 PLANNING POLICY CONTEXT
A detailed consideration of relevant planning policy specific to each environmental topic is contained in each topic chapter of the ES.
Details of the planning policy framework and a discussion of how the Development has been designed in accordance with this framework are included in the accompanying Planning Statement. The Planning Statement has been prepared to support the planning application but does not form part of the ES.
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5 WATER, CONTAMINATION AND SEDIMENT QUALITY 5.1 Introduction
This chapter addresses the potential impact on the environment, due to the proposed works by the presence of contaminated sediment or water. This chapter provides information on and assessment of;
• the baseline conditions, in relation to the sediment and the estuarine water, including laboratory analysis of sediment samples taken from the proposed jetty location,
• the mechanisms by which the proposed construction activities could mobilise contaminants in the sediment and thereby impact water quality,
• the potential for the construction work to impact water and sediment quality through the addition of contaminants,
• the suitability of disposal at sea or on land of dredging and pile sediment/soil arisings;
• what further investigation work and mitigation measures could be carried out to mitigate the identified risks. 5.2 Regulatory and Policy Framework
This impact assessment has been undertaken in accordance with current international and national legislation relating to protection of the surface water environment in the context of the proposed development. A summary of the relevant legislation and policies, the requirements of these policies and the proposed development response has been provided in Table 5-1 below.
Table 5-8 Regulatory References
Policy/Legislation Summary of Requirements Development Response
Water Resources Act Not to allow controlled waters to be Location of the jetty will include (1991/2003) significantly polluted. consideration of pile lengths required, It is a criminal offence to: which will be minimised and therefore minimise soil arisings -knowingly permit any poisonous, noxious or polluting matter or any Site investigation carried out to solid waste matter to enter any establish potential for contamination to controlled waters occur - cause or knowingly permit any Principal Contractor to be informed of trade effluent or sewage effluent to hazards and risks and required to be discharged into any controlled produce and comply with mitigation waters without a consent, or outside measures in method statements of the conditions of a consent.
Part 2A of the To protect controlled waters from Carry out a desk study to identify Environmental pollution by hazardous substances potential sources of contamination Protection Act (1990) in, on or under the land which could have led to the contamination of sediments in the river. This will inform the site investigation and any mitigation measures
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Policy/Legislation Summary of Requirements Development Response considered necessary where a risk is identified.
National Planning The document streamlines national Carry out a desk study to identify Policy Framework planning policy into a consolidated potential sources of contamination (March 2012) set of priorities, with the core theme which could have led to the being the delivery of sustainable contamination of sediments in the river. development and economic growth. This will inform the site investigation The Planning Practice Guidance and any mitigation measures relating to land affected by considered necessary where a risk is contamination refers to the identified. methodologies outlined in Part 2A of Consideration of waste reuse and the Environmental Protection Act disposal options
Contaminated Land To investigate and assess potential As above Report (CLR) 11 ‘The risk to sensitive receptors (including model procedures for controlled waters, and flora and the Management of fauna) from contaminated soil or Land Contamination’ water
The Water Framework Driver for water quality monitoring A WFD Screening Assessment has Directive (2000/60/EC) which is required to establish a been completed and is included in framework for the protection of Appendix 5-A inland surface waters, transitional waters, coastal waters and groundwater.
Marine and Coastal Part 5 of this Act enables the The Tamar Estuary MCZ is located in Access Act 2009 designation of MCZs. These are a two separate areas including the upper type of Marine Protected Area, reaches of the Tamar and Lynher which protect a range of nationally estuaries. The development is important marine wildlife, habitats, approximately 2km away from this geology and geomorphology. MCZs MCZ, at its closest point within the exist alongside European marine Lynher estuary. Sites, SSSIs and Ramsar sites to These potential receptors have been form an ecologically coherent considered in the assessment and network of marine protected areas. mitigation measures designed accordingly.
Conservation of The Regulations provide for the Covered in detail within Chapter 6 Habitats and Species protection of both Special Protection Regulations 2010 (as Areas (SPAs) and Special Areas for amended)’ Conservation (SACs) as part of the Natura 2000 network of protected areas across Europe. . The Regulations also provide protection for European Protected Species (EPS) from the deliberate capture, killing or disturbance. It is also an absolute offence to destroy or damage the resting site or breeding site of an EPS.
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5.3 Methodology 5.3.1 Introduction
This assessment has been undertaken with due regard to the Water Resources Act. The assessment has been carried out based on the principles outlined in MMO guidance and contaminated land guidance documents issued by the Department of the Environment Food and Rural Affairs (DEFRA) and the EA.
The Guidance requires a risk-based approach with the potential environmental risk assessed qualitatively using the ‘source-pathway-receptor’ pollutant linkage concept contained in Part IIA of the Environment Protection Act (1990) and CLR 11 ‘The Model procedures for the Management of Land Contamination’ (Ref. 5-1). For example, if the sediment is not contaminated then there is not a ‘source’ of contamination at the site and therefore there would not be considered to be a risk. Similarly, if the contamination in the sediment is not leachable then there is not a ‘pathway’ and it is unlikely that water quality would be impacted through dissolution.
A full Water Framework Directive Assessment is presented in Appendix 5-A.
This assessment is intended to meet requirements under the planning regime, and therefore is focused on potential contaminated land risks associated with the proposed construction works and the ongoing use of the site.
Maintenance and construction workers are not considered in this assessment as they would be protected through other regulation, e.g. Health and Safety at Work Act and Construction Design and Management Regulations 2007. Protection of construction workers and the environment during and following construction must be addressed as part of the development of method statements and risk assessments prior to any work being carried out on the site. However, the information provided in this report should be reviewed by the Principal Contractor to inform his risk assessment, in accordance with Construction Design and Management (CDM) Regulations. 5.3.2 The Study Area
The area covered by this study is defined by the proposed footprint of the jetty and the vessel approach area, the northern part of which is to be dredged. The majority of the vessel approach area, which will be reduced to a river bed maximum design dredge level of 12.6m below CD, falls within the area currently used for vessel approach to the existing jetty. Therefore only an area of approximately 0.73ha needs to be dredged, which will produce a volume of dredge arising’s for disposal of approximately 19,000m 3.
In addition, some dredging will need to be carried out to enable access to the western side of the jetty. This will bring the river bed levels down to approximately 5.6m below CD over an area of 1.36ha and will produce approximately 18,000m 3 of arising’s.
In addition, consideration has been given to the area over which an impact could occur, which due to the tidal nature of the river at this location, includes reaches of the river both up and downstream of the development site.
Public Register information and historical maps have been obtained for a radius of approximately 1km from the jetty footprint. Information has been obtained relating to potential sources of contamination and land quality at the Thanckes OFD site. Some basic information on the activities carried out at Devonport Dockyard has been obtained from the internet and the Client.
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5.3.3 Establishing Baseline Conditions
The baseline conditions have been established based on the following sources of information;
• Historical maps
• Public register information
• Land quality and site activity information for Thanckes OFD and Devonport Dockyard
• Surface water quality data for the River Tamar / Hamoaze
• Sediment laboratory analysis – total and leachable concentrations
Site Investigation The following site investigations have been carried out at or near to the site, and the information has been used in this report;
• Baseline Document for Maintenance Dredging in Plymouth Sound and Estuaries European Marine Site (Black and Veatch) - 2011 (Ref. 5-12)
• Dredged sediment analysis for the existing Yonderberry Jetty (Cefas) – 2004 and 2006 (data tables provided by the Client)
• Soil Mechanics 1984 – five boreholes drilled in a line from the foreshore at OFD Thanckes out towards the river channel, approximately between 40-100m north of the proposed jetty approach. Boreholes BH-G and BH-H were located in the northern/western approach channel.
• Hyder Consulting June and August 2013 – site investigation which included geophysics surveys and drilling fifteen boreholes. The investigation was centred around the previously proposed location of the jetty and jetty approach, to the north of the current revised location. The investigation provides a good indication of the geology of the site and includes some geophysics coverage and borehole locations which are on the currently proposed jetty site. Of particular relevance are;
o DBH03 and DBH04 which are in the area of the eastern jetty approach which will require dredging,
o MBH02, MBH03, MBH07, MBH08, and MBH11 are in or near (within ~15m) the area of the northern/western jetty approach,
o MBH03, MBH10 and MBH07 which are near to the proposed northern dolphins, and
o MBH08 which is at the proposed location of the jetty head.
Chemical analysis of sediment/soil samples taken from these boreholes was carried out, as discussed below.
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5.3.4 Assessing Effects
Overall Effect
In Section 5.6 the overall potential effects of the development have been assessed. The significance of impacts has been determined using the approach described in Chapter 3 of this ES, combined with current UK best practice approach as discussed below. Activities anticipated during the construction and operational phases have been identified and their potential effects discussed, and proposed mitigation measures identified.
The assessment of impacts on the water quality of surface waters within and near the study area has been made using three stages. Firstly a judgement is made as to the value of potential receptors within the water environment through the baseline study, and then a magnitude is assigned to each of the potential impacts identified. The assessment of the potential magnitude of impact, the ‘risk term’ is derived from the contaminated sediment risk assessment, which uses the criteria outlined in Tables 5-4, 5-5, 5-6 and 5-7 and is discussed below.
The overall significance of impacts, taking into consideration the mitigation measures outlined in Section 5.5, is then determined using the matrix presented in Table 5-3
Any potential effect assessed as being of moderate and negative significance or greater, would be considered significant and would require further consideration and action where possible/practicable.
The determination of value (sensitivity) of the surface water receptors has been applied using the criteria summarised in Table 5-2.
Table 5-2 Criteria for Determining the Value (Sensitivity) of the Hydrological Resource
Sensitivity Criteria Typical Examples
Very High Attribute has a Surface EU designated salmonid/cyprinid fishery high quality and water: Watercourse achieving Water Framework Directive (WFD) Class ‘High’ rarity on a regional or Site protected under EU or UK habitat legislation (Special Area of national scale Conservation, Special Protection Area, Site of Special Scientific Interest, Ramsar site)
High Attribute has a Surface Watercourse achieving WFD Class ‘Good’ high quality and water: Major cyprinid fishery rarity on a local scale Species protected under EU or UK habitat legislation
Medium Attribute has a Surface Watercourse achieving WFD Class ‘Moderate’ medium quality water: Water feature that supports an abstraction for agricultural or industrial and rarity on a use of between 50 and 499m 3/day local scale
Low Attribute has a Surface Watercourse that is not a fishery, achieving WFD Class ‘Poor’. low quality and water: Supports an abstraction for agricultural or industrial use of < 50m 3/day rarity on a local scale
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Table 5-39 Criteria for the Assessment of Overall Effect
Risk Term – See Importance/Sensitivity of Resource or Receptor Table 5-7
Very High High Medium Low Negligible
Very Large Large or Very Moderate or Slight or Slight Very High Risk Large Large Moderate
Large or Very Moderate or Moderate Slight Neutral or High Risk Large Large Slight
Moderate or Slight or Slight Neutral or Neutral or Moderate Risk Large Moderate Slight Slight
Slight Slight Neutral or Neutral or Neutral Low Risk Slight Slight
Very Low Risk Neutral Neutral Neutral Neutral Neutral
Contaminated Sediment/Soil Risk Assessment
In Section 5.4 the baseline conditions are described. This information has been used to develop a conceptual model of the site on which a risk assessment has been based. This risk assessment relates solely to the potential presence of contaminated sediments and their potential to impact water quality.
UK guidance for the assessment of the risk posed by the presence of contamination indicates that a risk does not exist unless a source of contamination is present, a sensitive receptor is present, and there is a pathway which could link them, i.e. source-pathway-receptor pollutant linkage. Therefore, in order to assess the potential effect of the development on the environment a Conceptual Site Model (CSM) has been developed by ascertaining the presence of a contamination source, identifying potential sensitive receptors, and identifying potential exposure pathways.
Based on this CSM a risk assessment has been undertaken which examines the likelihood of exposure occurring and the potential severity of the impact. The risk assessment is primarily qualitative, based on the criteria outlined below, but all available quantitative data has been used to inform the qualitative assessment.
The criteria used in the risk assessment in relation to the potential effect of the proposed development through contaminated sediment and soil are based on information presented in the following:
• CIRIA C552 (2001) Contaminated Land Risk Assessment: A guide to good practice;
• NHBC / EA/ CIEH (2008) R&D Publication 66: (Volume 1) Guidance for the Safe Development of Housing on Land Affected by Contamination; and,
• DEFRA (2012) Environmental Protection Act 1990: Part 2A. Contaminated Land Statutory Guidance.
The designation of risk is based upon the consideration of both:
• the severity of the potential consequence - this takes into account both the potential severity of the hazard and the sensitivity of the receptor
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• the magnitude of probability (i.e. likelihood) - this takes into account both the presence of the hazard and receptor and the integrity of the pathway
Severity (consequence) can be defined as the adverse effects (or harm) arising from a defined hazard, which impairs the quality of human health or the environment in the short or longer term. Definitions of different categories of severity are detailed in Table 5-4 below. In this section, only impact to the primary receptors controlled waters and human health are considered. The potential impact to ecological receptors is discussed in Section 6.
Probability can be defined as the chance of a particular event occurring in a given period of time. Definitions of different categories of probability are detailed in Table 5-5 below.
A contaminant linkage must first be established before tests for probability and consequence are applied. If there is no contaminant linkage then there is no potential risk. Any pollutant linkage assessed as posing a risk of moderate or above would require further consideration. The risk term determined is then used in the assessment of the overall effect according to the matrix outlined in Table 5-3.
Table 5-4 Classification of Potential Consequence (Severity)
Classification Human Health Controlled Water
Severe Short term (acute) risk to human health. Substantial pollution of sensitive water Concentrations present likely to result in resources. “significant harm” as defined by Part 2A.
Medium Chronic damage to human health. Pollution of sensitive water resources or Concentrations present that could result in small scale pollution of sensitive water significant harm. resources
Mild Slight short term health effects to humans. Pollution to non-sensitive water resources Exposure to human health unlikely to lead to significant harm.
Minor Non-permanent health effects to human health Insubstantial pollution to non-sensitive (easily prevented by means such as personal water resources protective clothing.)
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Table 5-5 Classification of Probability (Only applies if there is a possibility of a pollutant linkage being present)
High likelihood There is a pollution linkage and an event that either appears very likely in the short term and almost inevitable over the long term or there is evidence at the receptor of harm or pollution.
Likely There is a pollution linkage and all the elements are present and in the right place, which means that it is probable that an even will occur. Circumstances are such that an event is not inevitable, but possible in the short term and likely over the long term.
Low Likelihood There is a pollution linkage and circumstances are possible under which an even could occur. However it is by no means certain that even over a longer period such an event would take place and is less likely in the shorter term.
Unlikely There is a pollution linkage but circumstances are such that it is improbable that an event would occur even in the very long term.
Once the severity and probability have been classified for a pollutant linkage they can be compared to produce a risk category from very high risk to very low risk as shown in the matrix below.
Table 5-6 Classification of Risk
Probability
Consequence
Severe Moderate/Low Moderate High Very High
Medium Low Moderate/Low Moderate High
Mild Very Low Low Moderate/Low Moderate
Minor Very Low Very Low Low Moderate/Low
Table 5-7 Risk Classification Descriptions
Risk Term Description
Very High Risk There is a high probability that significant harm could arise to a designated receptor from an identified hazard at the site without appropriate remedial action or there is evidence that significant harm to a designated receptor is already occurring.
High Risk Harm is likely to arise to a designated receptor from an identified hazard at the site without appropriate remedial action. Remediation works may be necessary in the short-term and are likely over the longer term.
Moderate Risk It is possible that harm could arise to a designated receptor from an identified hazard. However it is either relatively unlikely that any such harm would be severe or if any harm were to occur it is more likely that such harm would be relatively mild. Some remediation work may be required in the longer term.
Low Risk It is possible that harm could arise to a designated receptor from an identified hazard, but it is likely, at worst, that this harm if realised would normally be mild. Any subsequent remediation works are likely to be relatively limited.
Very Low Risk It is a low possibility that harm could arise to a receptor, but it is likely at worst, that this harm if realised would normally be mild or minor.
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5.3.5 Consultation
We have consulted the MMO prior to carrying out this study. With respect to this chapter, they have consulted the EA and Cefas, and have indicated that the following issues must be considered by this chapter:
Table 5-8 Consultation Responses
Consultee Summary response Measures taken to address this response
MMO Sampling and analysis is to be undertaken by Cefas as Sampling was carried out by Fugro in the part of the Marine Licence application. course of the site investigation, and Given the information available to date OSPAR samples submitted to the Cefas guidelines suggest sampling at 3 locations within the laboratory in accordance with their proposed area to be dredged. Samples should be taken guidance. None of the samples analysed at surface and every 1m for every meter to be dredged. were subject to ‘non-conformity’. The applicant should follow the guidance on the MMO website (http://www.marinemanagement.org.uk/licensing/how/sa mple_analysis.htm) to ascertain analytical requirements.
Alternative waste disposal options must be considered Consultation was carried out with local community groups (Local Authorities, Tamar Group) to try to identify any local projects for which the waste arisings may be of use – none was identified. Consultation with local waste treatment and disposal contractors indicated that significant large scale near site (on the near shore) temporary works would be required in order to make the arisings acceptable to them.
The water quality section needs to include the other Addressed in Section 5.5.1 water quality issues from general construction, including use of machinery near water courses and risk of sediment run off from land construction site. The project will require the preparation of a Construction Environment Management Plan prior to commencement of works.
Consideration is required of the potential impacts on Addressed through intrusive investigation water quality and designated sites from contamination and risk assessment outlined in this within the sediment. If levels of contamination are Chapter significant and potential impacts are identified suitable methods and mitigation measures must be incorporated for all stages of the project.
If an Environment Agency water discharge activity No particular requirement needed over permit is required the EIA will need to address the and above the standard permit conditions requirements needed of the permit. assessed necessary by the EA.
EA No comment in relation to this chapter
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In addition, the following requests were put to Cefas by Hyder through MMO. Their responses are provided below.
Request to Cefas Cefas Response
Are you content that sufficient sampling and ‘In summary, the results show that material from the sample analysis has been carried out to characterise locations highlighted in yellow on the attached map are not the dredge areas? acceptable for disposal to sea, therefore two exclusion zones have been delineated on the attached map (shown as red lines) and I recommend material from these areas is not permitted to be Based on the sediment/soil chemical analysis disposed of at sea. Sediments from the exclusion zones would results, do you concur that dredge arisings need to be disposed of on land or alternatively used. The material are suitable for disposal at sea? from the remaining areas, shown on the attached map, have acceptable levels of contaminants and therefore this material can be disposed to sea.’ (Email 20/1/14). Hyder note - Plan provided by Cefas shows exclusion zone around MBH08 at 3m. This is the only exclusion zone relevant to the proposed development area. Dredging in this area will be above this depth (and other samples indicate that the sediment is no impacted at these depths) and therefore this exclusion zone only applies to piling. ‘Extension of the existing jetty dredge box north with associated capital dredge of 16,000m 3. This area has recently been characterised (sampling stations DBH03 and DBH04) and therefore does not require further sampling.’ (Email 26/3/14) With respect to the western dredge area - ‘I am content that the samples are representative of the dredge area and that the material from this location (surface to 2.5m depth) is suitable for disposal to sea.’ (Email 30/9/14) With respect to localised areas where the dredge depth will extend to upto 2.8m - ‘Cefas recommend that a 0.5m buffer is required when dredging material close to contaminated material. However, this is recognising errors on the actual depth of the sample and the dredge, therefore I would recommend that mitigation i.e. closed buckets could be employed in this area to minimise any re- suspension of contaminated sediment.’ (Email 28/10/14)
We are considering changing the location of ‘I am content that this area has been characterised sufficiently for the proposed jetty. Are you content that the contamination purposes and given the small volume of material information from the site investigation is (250m 3) associated with the jetty structure and dolphins, no further sufficient to characterise the pile arisings? sampling and sample analysis is required.’ (Email 5/8/14)
5.3.6 Limitations and Assumptions
The approach adopted by Hyder for the investigation and assessment of contamination at the site is based on an evaluation of the methodologies currently available, to decide which are most applicable to the site conditions and proposed end-use. No responsibility can be accepted for future changes in legislation or guidance that may affect the approach used or the findings of this report.
This report has been compiled using information from a number of sources, which Hyder believes to be trustworthy. However, Hyder is unable to guarantee the accuracy of information provided by others. This report is based on information available at the time of writing.
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Consequently, there is potential for further information to become available which may affect the conclusions drawn in this report, for which Hyder cannot be held responsible.
It should be noted that, due to the nature of a ground investigation, the ground conditions between exploratory holes might vary from those identified. The coverage and scope of the investigation was designed based on the information available at the time and current best practice and is considered suitable to provide a good representation of the site. Since undertaking the marine surveys, the development proposals have changed. However, the area surveyed effectively covered the revised Development footprint and is considered suitable to represent the proposed development. 5.4 Description of the Baseline Conditions 5.4.1 Environmental Setting
Geology The British Geological Survey (BGS) geological map for the area (Ref. 5-3) indicates that the site is underlain by Upper Devonian Slates.
Previous site investigation information (Soil Mechanics 1984 – Ref. 5-4) has been provided by the Client, which includes logs for five boreholes drilled in a line perpendicular to the shore and parallel to the existing jetty. This information is included in Appendix 5-B. The information gives an indication of the depth of the sediment and soft soils above the bedrock level at that time, as well as the nature of the soft and hard superficial strata in a progression from the foreshore out towards the centre of the river to the proposed extent of the new jetty. The logs indicate that the superficial soils are between 0.5m thick near to the foreshore, generally approximately 3.5m – 4.5m thick along the length of the jetty and up to 12m thick at the furthest extent of the proposed jetty.
During a site investigation carried out by Hyder in August 2013, in which fifteen boreholes were drilled, it was found that there is a steep rock escarpment semi parallel with the proposed line of the jetty head.
The thickness of the river sediment deposits in the shallow boreholes drilled in the area to be dredged was generally found to be greater than 3m. The thickness was proved in one borehole (MBH08) approximately 8m from the outer edge of the proposed jetty head location as being approximately 5.0m below the sediment level (bsl). However, a further borehole (MBH10) to the north and along strike of the proposed jetty location proved a thicknesses of sediment down to 20.8mbsl indicating that there is a steep scarp slope leading to variable depths across a short distance.
The top of the slate was encountered at depths of between 7.45mbsl and 20.4mbsl to the north and west of the proposed jetty head location indicating that there may be a fault zone to the north of the study site. Borehole BHG of the 1984 Soil Mechanics investigation indicated the depth to slate as 4.3mbsl. The thickness of sediment deposits to the north of the proposed jetty approach in MBH01 is approximately 5.2mbsl.
The sediment/superficial deposits are described in both investigations as comprising very soft or soft organic slightly sandy (fine) silty clay or clayey silt with occasional shells. This is underlain by weathered slates at the depths indicated above, the description of this bedrock strata indicating that the competency of the rock generally increases with depth and with an associated reduction in weathering.
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The slates beneath the site are classified by the EA as a Secondary Aquifer but any groundwater in the vicinity will have been impacted by saline water and public register information (Appendix 5-C) indicates that there are no groundwater abstractions within 1km of the site. Water abstraction licences listed are from the River Tamar.
Hydrology and Sensitive Receptors Surface water features local to the site are illustrated in Drawing 5-1. The site lies within the Hamoaze reach of the estuary of the River Tamar, which represents a sensitive receptor with regard to surface water quality. Due to the flow dynamics of the estuary water quality both upstream and downstream of the construction site has the potential to be affected. As discussed in Chapter 6 Ecology, the proposed development site is located within the Plymouth Sound and Estuaries SAC, designated for estuarine habitats and migratory fish species. In addition it is approximately 1.5km away from the Tamar Estuaries Complex SPA, designated for internationally important populations of wintering and on-passage birds. There are also two MCZs within the vicinity of the project (Drawing 1-4); Tamar Estuary Sites to the north and Whitsand and Looe Bay to the south. These MCZs were designated under the Marine and Coastal Access Act 2009 (w-3). Of particular note to this study is the importance of the estuary to migratory fish which are sensitive to changes in water quality.
On this basis the River Tamar is assessed as being of very high sensitivity .
There are no other surface water receptors within the study area, with the closest surface water body being located approximately 100m to the south of Yonderberry Point. This is a creek that drains an area of mudflat known as the Thanckes Lake. 5.4.2 Potential Sources of Contamination
Surrounding Historical and Recent Land Use The following potential primary sources of contamination have been identified and are discussed below:
• Thanckes OFD
• Naval Dockyard Activities
• Historical industrial activities including – mining, boat/ship building and maintenance, fishing, agriculture
• Recent industrial activities – including discharge of waste water, pollution incidents, current industrial activities
Thanckes Oil Fuel Depot (OFD)
The following information has been obtained from an Environmental Risk Assessment carried out for Thanckes OFD by the MOD Environmental Science Group in May 2008 (Ref 5-6), and a draft desk study Land Quality Assessment (LQA) report produced by SKM Enviros in 2013 (Ref. 5-6). These reports were produced to identify potential environmental hazards, and to assist in the environmental management of the site. We have used the relevant information to identify potential contaminants used and stored on the Thanckes OFD site which may have impacted the sediment and soils in the area of interest.
The following is a list of the most likely potential contaminants which could be present due to activities on the Thanckes OFD site.
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These include:
• Petroleum hydrocarbons and mineral oils – diesel, aviation fuel, fuel oil, contaminated waste water from ships (sullage)
• Polychlorinated biphenyls (PCB) – in conducting oils formerly used in electrical equipment
• Polycyclic aromatic hydrocarbons (PAH) - various industrial processes associated with partial combustion.
Other hazardous substances stored in significant quantities at Thanckes OFD include the following:
• Fire fighting foam / Film Forming Fluoro Protein (FFFP)
• Gas oil marker concentrate
• Antifreeze
The 2013 LQA report produced by SKM Enviros concluded that the potential risk to surface water from the storage of these other hazardous substances is ‘low’. This assessment has been reached as these substances are stored in lesser quantities in drums and Intermediate Bulk Containers (IBCs). Materials are generally stored in buildings with concrete floors although not all have secondary containment. There are no recorded incidences of hazardous substances being discharged to ground.
Dockyard Activities
We have referred to the Department of the Environment Industry Profile for Dockyards and Dockland (Ref. 5-7) to provide general information on the type of contaminants which may be associated with dockyard activities. We have also referred to a report produced by Babcock Marine on the environmental monitoring of radioactivity around Devonport Dockyard (Ref. 5-8).
Identified potential contaminants from Devonport Dockyard include:
• Metals, including tin compounds – from paint and anti-foul, in fuel, spillage of cargo (including metal ores and coal/coke), timber treatment, metal working
• Petroleum hydrocarbons and mineral oil – storage and use of fuel, lubricating oils, hydraulic oils, paint, tar
• Pesticide – timber treatment and storage
• PCBs – formerly used in conducting oils within electricity substations and transformers
• PAHs including phenols – rope and sail making (treatment with tar), industrial processing including partial combustion
• Radionucleides – used to power submarines. Including tritium, cobalt-60, carbon-14.
Historical Activities
Study of historical maps indicates that there have been the following potentially contaminative activities which have the potential to have impacted the site, either because they are
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downstream and near, or upstream of the area of interest. Consideration has also been given to the tidal nature of the river at this location.
The historical maps are reproduced in Appendix 5-D.
Table 5-9 Summary of Historical Potential Sources of Contamination
Activity Date Approximate Distance Potential / Likely Contaminants and Location
Smith’s Shop 1867 875m ESE, downstream Metals, hydrocarbons
Gas and coke works 1867 875m ESE, downstream Metals, hydrocarbons, sulphur compounds, cyanide compounds, phenols, alkali, acid
Dock yard 1867 675m ESE, downstream Metals, hydrocarbons
Quarries 1867 1km NE, upstream Metals, hydrocarbons
Keyham chemical works 1867 1.5km NE, upstream Metals, hydrocarbons, solvents, other
Sawmill 1888 1.1km NE, upstream Metals, hydrocarbons
Chemical works 1888 1.1km S, downstream Metals, hydrocarbons, solvents, other
Gas works (Torpoint) 1888 1km S, downstream Metals, hydrocarbons, sulphur compounds, phenols, cyanide compounds, alkali, acid
Dock yard expansion 1907 500m E, upstream Metals, hydrocarbons, solvents, radionuclides
Thanckes OFD constructed 1920 100m W, upstream Metals, hydrocarbons (Ref. 5-6)
In addition to the sources identified on the historical maps, it is known that the land and water around the site have, for many centuries, been used for farming, fishing and mining. The most likely potential contaminants associated with these activities include metals, hydrocarbons, pesticides, ammonia, and phosphate.
Recent Activities
Study of public register information indicates that there have been the following potentially contaminative activities which have the potential to have impacted the site, either because they are downstream and near, or upstream of the area of interest. Consideration has also been given to the tidal nature of the river at this location.
The public register information is reproduced in Appendix 5-C.
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Table 5-10 Summary of Recent Potential Sources of Contamination
Activity Details Approximate Distance and Location
Discharge Consent From Thanckes OFD for trade Discharge point marked on the (current) effluent into the Tamar Estuary / existing jetty Hamoaze ~20m S, downstream
Discharge Consent From Thanckes OFD for trade Discharge point marked at root of (current) effluent / site drainage into the existing jetty Tamar Estuary / Hamoaze ~30m S, downstream
Discharge Consents From Thanckes OFD for trade Discharge points marked on (discontinued) effluent / site drainage into the northern shore of OFD Thanckes. Tamar Estuary / Hamoaze. ~560-800m NW, upstream Surrendered 2010
Discharge Consents From Devonport Dockyard for trade Discharge points marked (current and discontinued) effluent, site drainage and sewage throughout dockyard area. into the Tamar Estuary / Hamoaze ~525-1000m E, up and downstream
Discharge Consents Held by South West Water for ~530-1000m NW, SW, E, up and (current and discontinued) treated sewage and trade effluent downstream and surface water
Integrated Pollution For Thanckes OFD for disposal of Immediately west of site Prevention Control (IPPC) waste oil >10 tonnes/day permit
Pollution incidents to 8 incidents recorded. 7 minor ~525-910m, up and downstream controlled waters incidents, 1 significant incident (at Devonport Dockyard, ‘other chemicals’, 1993). Oil, sewage, other chemicals, algae. 1993-1995 listed
Landfill Former site at Torpoint. Multiple ~525m SW waste types allowed. Closed prior to Drain from landfill ~180m SW, 1993. downstream
Waste management facility Thanckes OFD. Processing of ~150m W, upstream waste oil.
The discharges from Thanckes OFD have the potential to have included fuel. The discharges from Devonport Dockyard have the potential to have included those chemicals outlined above, including fuel and radionuclides.
There are other discharge consents within 1km of the site, held by private individuals for domestic sewage disposal. These are considered unlikely to have had a significant impact on the site conditions.
The Contemporary Trade Directory indicates that there are numerous small businesses which carry out potentially contaminative activities (e.g. garages, printers etc.). Any pollution of the ground from these features is unlikely to have been sufficiently gross to have significantly
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impacted the River Tamar, and therefore the area of interest. This assumption is supported by the pollution incident records.
Potential Secondary Sources / Likely Contaminants Contaminants which are considered most likely to be present in the sediments in significant concentrations are listed below:
• Petroleum hydrocarbons and mineral oils
• PCBs
• PAHs
• Phenols
• Metals, including tin compounds
OSPAR guidance (Ref. 5-9), used by MMO and Cefas to regulate the protection of the marine environment, indicates that PAH, PCB, and metals are of particular concern with respect to the marine environment. Various research documents (Refs. 5-2, 5-10, 5-11) indicate that metals including tin compounds, PAH and PCB are of particular concern in the Tamar estuary and Plymouth Sound area. Several of these substances (PAH, metals) are also defined as WFD Priority Substances, which are deemed harmful to the water environment.
Radionuclides could be present but it is unlikely that these would be at significant levels as they are closely monitored and regulated through the discharge permitting process. 5.4.3 Surface Water Quality
The Hamoaze forms part of the Plymouth Sound Water Body, which is monitored for chemical and ecological quality under the requirements of the WFD. This water body is designated as heavily modified, due to substantial changes to its physical character resulting from physical alterations caused by human use. As a result it has an objective status of ‘Good’ ecological potential and currently achieves this status.
However Plymouth Sound does not meet the acceptable standards for chemistry and is classed as failing the requirements of the WFD for chemical water quality. This failure is based on threshold exceedance of Tributyltin compounds, which are defined by the Directive as a Priority Hazardous substance. Further details are included in the WFD Assessment provided in Appendix 5-A, which has screened the proposed development against WFD objectives.
Results from National Monitoring Programme surveys conducted between 1992 and 1995 revealed no evidence that Environmental Quality Standards (EQS) for Cadmium (Cd), Copper (Cu), Nickel (Ni), Lead (Pb), and Zinc (Zn) were exceeded. The EQS for Tributyltin (TBT) was often exceeded. Little TBT was found to enter the estuarine system from freshwater inputs i.e. the Rivers Tamar, Tavy and Lynher which were all found to have annual concentrations of TBT below the limit of detection, indicating that the EQS exceedance is attributable to sources within the estuary.
The Tamar Estuaries Management Plan 2013 to 2018 identifies marine litter as a problem that impacts on the water environment, and other sources of pollution reported as agricultural runoff and point source discharges. The Tamar Estuaries Consultative Forum list disturbance of contaminated sediments due to dredging as a potential challenge to achieving good estuarine water quality.
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There are no designated Bathing Waters or Shellfish Waters within the study area, defined as a 1km radius around the proposed new jetty as illustrated in Drawing 5.1, although the development lies within 3km of the Designated Shellfish Waters of the Lynher and the Classified Bivalve Mollusc Harvesting Area in the Tamar. 5.4.4 Sediment Quality
The existing sediment quality has been ascertained through the following information sources:
• Baseline Document for Maintenance Dredging in Plymouth Sound and Estuaries European Marine Site (Black and Veatch) - 2011 (Ref. 5-2)
• Dredged sediment analysis for the existing Yonderberry Jetty (Cefas) – 2004 and 2006 (data tables provided by the Client)
• Sediment analysis of samples from on site and to the north of the site (Hyder) – June and August 2013.
• This investigation work included the drilling of boreholes and the taking of near surface ‘grab’ sediment samples from twenty four locations on and to the north of the site, and the analysis of up to thirty nine sediment samples for total concentrations of determinands and eight for leachable concentrations.
The boreholes located within the site area include DBH03 and DBH04 which are in the area of the eastern jetty approach which will require dredging, MBH03, MBH10 and MBH07 which are near to the proposed northern dolphins, and MBH08 at the location of the jetty head. MBH02, MBH03, MBH07, MBH08, and MBH11 are in or near the area of the northern/western jetty approach.
The locations on or very close to the area of interest from which samples were analysed include MBH02, MBH03, MBH08, DBH03, and DBH04, and tritium in a grab sample taken from Sample Site 8. A total of nineteen samples were analysed from these locations.
• The samples were variously analysed for metals including tin compounds and hexavalent chromium, total petroleum hydrocarbons (TPH), mineral oil, semi volatile organic compounds including PAH and phenols, PCB, pH and organic matter. Two samples (combined) were analysed for tritium.
• The leachability testing was carried out using a matrix based on the likely salinity of the estuary in order to represent (as closely as possible) the conditions on the site. The one sample tested from the site in June 2013 was leached using a matrix which had a pH of 6.4 which is probably too low to be representative of the estuary but would indicate the worst case for leachability of metals which will leach more easily in acidic conditions. The two samples tested from on site in the August 2013 investigation were leached with a matrix at a pH of 8.5 which is more representative of the likely estuarine conditions. The leachate samples were analysed for the same determinands as above, plus one combined sample for tritium.
• These determinands are considered to be the most likely to be present and are also those which are of the greatest concern to the UK marine environment. In discussion with the Cefas laboratory with respect to determinands which require investigation to support a dredging licence application, they indicated that radionuclides would not normally be analysed as this is regulated under the discharge permitting system. The
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tritium analysis carried out was to test our assumption that this is unlikely to be present at significant levels.
The data from the first two information sources listed above, summarising the results of sediment chemical analysis in the River Tamar and Plymouth Sound, are included in Appendix 5-E. (Note: some of the highlighting in the tables is incorrect). The chemical analysis data produced by sediment sampling at the site in June and August 2013 is included in Appendix 5- F.
Drawings showing the locations of the sediment sampling are included as Drawing 5.2, showing the locations of the June ‘grab’ samples, and Drawing 5.3 showing the proposed jetty borehole location plan. The locations of the samples taken were targeted at the anticipated location and configuration of the proposed jetty at that time. This has changed but the results are still applicable to assessment of the dredge arisings from the jetty approach, and to the arisings from the piles.
In order to provide an indication of the significance of the total concentrations found in the sediment samples, the data has been compared to OSPAR/MMO Action Levels (AL) (Refs. 5-9 and 5-12). In the absence of a UK Action Level, Canadian guidance values have been used (Ref. 5-13), namely threshold effect levels (TELs) and probable effect levels (PELs). The leachate sample analysis results have been compared to European EQS for saltwater. The UK Action Levels and Canadian Effect Levels are provided in Appendix 5-G, but a brief explanation is given below.
• Below Cefas Action Level One (AL1) : In general, contaminant levels in dredged material below Action Level 1 are of no concern and are unlikely to influence the licensing decision.
• Between Cefas Action Levels One (AL1) and Two (AL2): Dredged material with contaminant levels between AL1 and AL2 requires further consideration and testing before a decision will be made (e.g. other factors would be considered, such as the sensitivity of the disposal site, leachability analysis etc).
• Above Cefas Action Level Two (AL2) : Dredged material with contaminant levels above AL2 is considered unsuitable for sea disposal. This most often applies only to a part of a proposed dredging area and so that area can be excluded from disposal at sea and disposed of by other routes, e.g. landfill.
• Below the Canadian TEL ; the minimal effect range within which adverse effects rarely occur.
• Between the Canadian TEL and PEL ; the possible effect range within which adverse effects occasionally occur.
• Above the Canadian PEL ; the probable effect range within which adverse effects frequently occur.
The general background information for the River Tamar and Plymouth Sound indicates that;
• In summary, elevated concentrations of metals including tin compounds, PAH and PCB are found widespread throughout the area.
• The 2011 data indicates average concentrations greater than AL2 were found in the dockyard for arsenic, cadmium, mercury, zinc and PCB. In the River Tamar and at Carbeile Mill average concentrations were found to be above AL1, but not AL2, for arsenic, cadmium, chromium, mercury, lead, zinc, tin compounds and PCB. When
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compared to Canadian Effect Levels, several PAH compounds were found to be above the higher ‘probable effect levels’.
• In 2004, samples taken at Yonderberry Jetty were tested for PCB and tin compounds. Neither showed concentrations greater than AL2, and the individual PCB compounds were no greater than the AL1 for total PCB.
• In 2006, concentrations in samples taken from Yonderberry Jetty were above AL1 for arsenic, mercury, copper, nickel, lead, and zinc. They were not elevated i.e. below AL1, for tin compounds. When compared to Canadian Effect Levels, several PAH compounds were found to be above the higher ‘probable effect levels’.
The data from the analysis of sediment samples taken from the site area (in June and August 2013) shows;
Leachable Concentrations
• Neither of the two samples (MBH08 0.6m and 5.0m) analysed from the site area showed elevated concentrations of the determinands tested when compared to EQS for “other surface waters” (including the marine and estuarine environment).
• The leachate analysis showed no detectable concentrations for the majority of hydrocarbon determinands, including PCB and PAH compounds. Concentrations greater than the laboratory detection limits were found for mineral oils in MBH08 5m (28ug/l). There is no EQS for hydrocarbons of this type, but these are not considered to be of significantly high concentrations and are likely to be associated with natural organic matter accumulated at the interface between the river deposits and the top of the slate encountered at this depth in the borehole.
• Two samples (combined from grab samples taken from Sites 8 and 10) analysed for tritium showed no detectable concentration.
Total Concentrations in Sediment
The following provides a summary of the analysis results when compared to the guideline criteria for disposal of sediment at sea. It should be noted that the samples were analysed at two different laboratories using different techniques and therefore there is potential for different readings to be obtained due to this factor rather than a reflection of the actual soil conditions. In this section we have reviewed all of the data together in order to provide a general impression of the conditions on the site.
• In the sixteen samples analysed from the site area for metals, several of the metal determinands show total concentrations greater than the AL1, but not greater than the AL2. These include arsenic (6 samples), cadmium (9 samples), total chromium (1 samples), copper (7 samples), lead (7 samples), nickel (15 samples), tributyltin (1 sample) and zinc (6 samples).
• One of the sixteen samples analysed for arsenic showed concentrations greater than AL2. This was taken from MBH08 3.0m. A sample taken from MBH02 3.0-3.8m showed a concentration above the AL2 in one test (140mg/kg), but a duplicate test showed a concentration much below the AL2 of 9.9mg/kg. All other metals were below the AL2.
• One sample (MBH08 3.0m) showed a concentration for the sum of 25 PCB congeners of 0.5mg/kg, greater than the AL2 of 0.2mg/kg. Six of the seventeen samples analysed showed concentrations greater than the AL1 but less than the AL2. PCB strongly sorbs
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to cohesive sediments and therefore is not easily mobilised into water. This isolated marginally elevated concentration is therefore not considered to be indicative of a significant hazard. This is reinforced by the lack of PCB found in the leachate samples.
• Four of the fifteen samples analysed for PAH compounds showed concentrations greater than the PELs for ten of the sixteen compounds tested. This is not considered to be indicative of widespread significant contamination with potential to impact water quality, and this conclusion is supported by the lack of PAH compounds found in the leachate samples.
• Seven samples were tested for TPH and ten for Total Hydrocarbon Content (THC). The TPH analysis showed detectable concentrations only in the carbon range C16-40 in three of the five samples, and the THC analysis showed notable concentrations (greater than 10mg/kg) in six of the samples analysed. The maximum detectable TPH concentration was 89mg/kg (MBH08 3.5m) and the maximum b concentration was 1,750mg/kg (MBH08 3.0m)
There is no UK or Canadian guidance value for TPH in the marine environment, and therefore it is difficult to assess the significance of these concentrations. However, in general terms these concentrations are low when compared to criteria for land based assessment, and it is of note that the leachability testing showed no leachable concentrations.
Summary
The concentrations found on the site in the sediment analysis, are consistent with the concentrations found elsewhere in vicinity of the site.
Evidence of metals, PCB and PAH compounds were found as total concentrations in the sediment samples across the site, the majority at concentrations below the upper guideline limits.
The only exceedances of the upper limits were for arsenic and PCB 25 found in the sample taken from MBH08 3.0m, and from one of two samples analysed from MBH02 3.0- 3.8m. MBH08 is located at the proposed jetty head and therefore this is of relevance to arisings from pile drilling in this area. The dredge depth for the northern/western channel is shallower than 3m and therefore it is concluded that the sediment mass which will be dredged has not been impacted.
The samples did not show any elevated concentrations in the leachate analysis indicating that they are not readily leachable into the estuarine waters. 5.4.5 Conceptual Site Model and Risk Assessment
During Construction Phase Sources
Contaminated Sediment
The potential source of impact addressed here is the release of contaminants from the sediment beneath the site. The construction works will inevitably lead to disturbance of the near surface sediments, and the drilling of piles will bring deeper sediment and soil to the surface where it will be deposited.
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Analysis carried out to date indicates that the sediment has some elevated concentrations of metals, PAH and PCB compounds, above lower action/effect levels but generally below upper action/effect levels, but that there is a very low potential for these contaminants to be leached into the water.
It is of note that the leachability analysis was completed using a saline matrix at a pH representative of marine conditions, and the sediment sample was agitated in the leachate matrix.
The concentrations found in the sediment samples on the site are consistent with those found elsewhere in the estuary near to the site, and the site works activities proposed are similar to those carried out nearby.
During the construction works, disturbance of the sediment at any one location will be of short duration so that any locally elevated concentrations not identified will have limited temporal impact.
Receptors
The primary receptor of consideration in this assessment is surface water quality in the River Tamar, and whether it could be significantly changed by the proposed development. This receptor is assessed as being of very high sensitivity due to its SAC designated status associated with water based sensitive habitats and the nearby SPA associated with protected birds which rely on the water environment habitats.
Secondary potential receptors are the ecological systems of the estuary, and people coming into contact with water. The critical receptors are:
• The flora and fauna in the surrounding ecologically protected area (absorption, uptake). In particular, protected fish species, marine mammals and protected flora. The risk to ecological systems is discussed in Chapter 6.
• People coming into contact with the water (ingestion, dermal contact, inhalation of water vapour).
Pathways
The pathway for potential impact on the quality of surface water due to contaminants in the sediment/soil is through;
• dissolution of contaminants out of sediment/soil,
• suspension of contaminated or non-contaminated particulates, and
• subsequent migration up or downstream of the site (through convection) due to wave, wind and tidal action.
It is important to note that the baseline sediment and water quality data shows that:
• there are already elevated concentrations of metals and hydrocarbon concentrations in the water so that any small dissolution of contaminant during the construction works is unlikely to have a significant impact.
• The presence of contaminants in the sediment means that there is a theoretical potential for disturbance of the sediment to lead to their release into the water.
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Leachability testing indicates that this is unlikely to occur as dissolved phase contamination, but particulate transport cannot be ruled out.
Table 5-11summarises the assessment of the risk posed by the potential source-pathway- receptor pollution linkage identified above. The mitigation measures which will be included at each stage of the proposed construction are discussed in Section 5.5.
Table 5-11 Summary of Contamination Risk Assessment
Potential Potential Consequence Probability Risk Source Receptor (without mitigation)
Contaminated Surface water Medium – the Low likelihood – some elevated Moderate/Low – Sediment quality surface water is concentrations have been found mitigation measures Metals, important for but these are consistent with should be considered hydrocarbons ecological levels in the surrounding area and and are discussed below receptors and is the proposed activity will be short assessed as lived and is similar to that carried being of very out nearby. high sensitivity
Human Health Mild Low likelihood – the river is used Low – mitigation for water sports so that exposure measures to protect could occur but concentrations are surface water will also unlikely to be very high reduce any residual risk to human health During Operational Phase The proposed location and design of the jetty will not increase the potential risk to the environment over and above that posed by the existing jetty. The potentially contaminating activities carried out on the proposed jetty will be the same as for the existing i.e. receiving and delivering fuel and the possible rare use of fire fighting foam. The risk will inherently be reduced by the new and improved infrastructure. 5.5 Design and Mitigation
The following section outlines the identified activities which may lead to an effect during the construction and operational phases, and the design and mitigation measures which are anticipated at this stage. Construction may have implications for the physico-chemical quality of waters downstream of the construction works, with potential for impacts on riverine habitats and species, as detailed in Chapter 6 Ecology. 5.5.1 During Construction Phase
Prior to construction a Construction Environmental Management Plan (CEMP) will be prepared that will incorporate environmental mitigation measures and procedures including Pollution Prevention and Management Plans and Method Statements to include surface water protection. The CEMP will take cognisance of the Water Resources Act (OPSI, 1991), EA guidance (including Pollution Prevention Guidelines) and CIRIA guidance (CIRIA 2005 & 2001) (Refs 5- 14, 15, 16 and 17). Disturbance of Sediment and Piling Activities Construction activities have the potential to temporarily add significant sediment loads local to the particular activity due to the disturbance of river bed materials/existing deposits of sediment
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and silt. During the construction work there will be some activities which require contact with the river bed and/or may cause considerable disturbance of the water, both of which may encourage near surface sediment to become suspended in the water column. This may have an impact either through mobilising contaminants, or through increasing turbidity and thereby resettlement on the river bed impacting benthic flora and fauna. Due to the size of the river and the river flow rates it is considered unlikely that this effect would be widespread.
The installation of piles for the proposed mooring dolphins, along the jetty approach and at the jetty head has the potential to disturb sediments, and will lead to the production of arisings.
During the construction works measures will be taken to minimise disturbance of the sediment, and to contain the migration of sediment. These will include:
• Taking additional precautionary measures while working in any locations identified as having elevated concentrations of contaminants and where there is potential for sensitive receptors at that location to be impacted(this is discussed further in the ecology assessment in Chapter 6). Mitigation measures will depend on the activity being carried out and the machinery being used. The elevated concentrations of arsenic and PCB 25 (that is those greater than AL2) were only identified in borehole MBH08 so that particular mitigation measures will be focussed on this location.
• Minimise as far as possible the extent of work requiring contact with the river bed.
• Ensuring the contractor uses methods which will minimise sediment disturbance, sediment migration and arisings. This includes ensuring that best practice and available plant are used in the design and execution of the works. This will include standard measures such suction dredging plant, and flush containment and collection during piling.
Use and Storage of Contaminating Substances During the construction period it is anticipated that there will be bulk storage and use of contaminative substances on the site, both on the land and on the river. These are likely to include fuel, lubricating oils, antifreeze and hydraulic oils for machinery. Also, the use of construction materials such as cements and concrete and generated construction wastes (solid waste and wastewater). Risks of pollution are associated, for example, with the emptying and flushing of existing fuel and sullage pipelines during demolition of the existing jetty, operation of two land based site compounds, accidental spills/leaks, and inappropriate storage or disposal of these materials.
Measures will be taken to ensure that contaminating substances are properly contained, during storage and use, both in the marine operations and the land operations. These include:
• Pollution Prevention Guidelines 5 (PPG5) published by the Environment Agency, 2007, for Working In or Near a Watercourse will be followed as a minimum standard. This includes recommendations for fuel containment and the use of less hazardous types of machinery oil.
• All bulk storage of fuel, oils and other contaminating substances will include secondary containment. Emergency spill/leak containment kits will be available throughout the construction site where contaminative substances are being used or transported. An emergency spill response procedure will be put in place and conveyed to all site staff.
• Best practice procedures will be used to contain potentially contaminating substances during the demolition of the existing jetty structures and construction of new jetty structures.
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• Refuelling, repair and maintenance of land based construction plant will be carried out within a designated bunded area to avoid pollution from spillages and leaks.
• Measures will also be put in place to contain all demolition and construction wastes, to prevent waste falling onto the estuary bed or into the water column.
Sediment Run-off from the Land Where land-based construction activities are undertaken, activities such as stripping of vegetation, stockpiling of soils and disturbance of soils in combination with flows of surface water runoff across the works areas have the potential to generate runoff that is high in silt and particulates.
During construction, best practice will be used to ensure that excess sediment/soil run off from the land construction site does not occur. Controlling measures will include:
• Carry out site investigation in the locations affected by the proposed development, including chemical analysis of soil samples. Where significantly elevated concentrations (assessed based on current UK guidance and regulation) of determinands are identified additional remediation measures will be taken. Depending on the volume of soil impacted, this could include removal and off-site disposal of the impacted soils, or local containment.
• A Drainage Management Plan will be produced to ensure that surface water runoff from construction compounds is appropriately managed and treated prior to entering into any waterbody.
• Containment of soil stockpiles.
• Hardstanding and roads will be cleaned frequently where soil is being deposited from vehicles.
• Cleaning of vehicles and equipment will be carried out in an area with drainage containment.
Waste Soil/Sediment The proposed development requires the dredging of up to 2.5m of sediment from the area in front of the northern dolphins on the east side of the jetty. At the time of writing this report the volume of sediment arisings from the dredging is estimated to be approximately 18,000m 3 (subject to confirmation at detailed design stage). Sediment samples were taken from two locations within the proposed dredge area (DBH03 and DBH04), at metre intervals through the proposed dredge depth at each location, as advised by Cefas, in order to characterise the dredge materials. Sediment samples were taken and stored in accordance with Cefas guidance and were submitted to Cefas for analysis.
In addition, approximately 18,000m 3 (subject to confirmation at detailed design stage) of sediment will be dredged from the western side of the jetty up to a depth of 2.5m. The ten samples analysed from MBH02, MBH03 and MBH08 are considered to be most representative of the dredge arisings from this area.
The drilling of the piles which will support the structure is likely to be carried out using a method which requires the removal of sediment and soils. Representative samples were analysed from varying depths throughout the different strata from 1m to 9m (refer to the results in Appendix 5- F). It is considered that the likelihood of there being significant levels of contaminants with potential to be mobilised below a depth of 10m is low, not least because the vast majority of the
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piles are anticipated to be in the rock below this depth. Arisings from the bedrock are likely to comprise silty sandy gravel. The proportion of the piles in the river deposits (sediment) and in the rock is estimated to be 52% and 48% respectively.
European and UK legislation and guidance on waste management requires that a waste producer must take measures to reduce and reuse waste, and that disposal is only a last resort. Consultation with MMO has indicated that disposal of sediment at sea should be avoided where possible and consideration should be given to reuse or disposal elsewhere.
In the course of this study we have consulted with the relevant Local Authorities, statutory bodies, the Tamar Estuaries Consultative Forum, and with the MOD agencies to identify any development projects proposed in the local area which may benefit from the sediment/soil arising from the jetty construction. To date, no suitable scheme has been identified but this process will continue later in the construction period.
We have also consulted with waste management companies who operate waste treatment and disposal facilities in the local area. There are two or three locations within Devon and Cornwall where dredge arisings can be accepted and used for restoration purposes. However, the dredged sediment straight from the river would have to be sufficiently dried before it could be transported and before it would be acceptable to be received by these sites. This would require a considerable logistical and economical challenge and it is considered that the environmental impact of the treatment and transport process would outweigh the benefit of avoiding disposal at sea.
The following provides discussion of the different options for managing the soil/sediment arisings based on the information available at present.
Disposal at Sea
The results of chemical analysis of sediment samples carried out by Hyder in June and August 2013 have been reviewed with reference to criteria defined by MMO and Cefas in order to ascertain whether disposal at sea is likely to be considered appropriate.
This review has found that only the sample taken from MBH08 3.0m shows concentrations greater than the upper criteria, and that the samples taken from the area to be dredged at the northern end of the jetty approach pocket do not show elevated concentrations.
Through our review of the analysis results, and consultation with Cefas it has been concluded that the arisings from the piles near to MBH08 are not suitable for disposal at sea and is not suitable for side casting/depositing in the site area. Therefore pile arisings from within the exclusion zone will be collected and disposed of differently, as discussed below.
For the remainder of the pile arisings (estimated as approximately 250m 3), based on the chemical analysis data reviewed from ground investigation work, the relatively small total volume, and using the mitigation measures outlined above, it is concluded that these arisings will be deposited immediately around each pile location. This is common practice, has been used on other projects in the Tamar Estuary, and is generally not considered an issue with respect to water quality, but it may have site specific ecological implications. Where additional sediment loading is an ecological concern (e.g. due to smothering of benthic flora and fauna), pile arisings will be collected rather than deposited. This is discussed in more detail in Chapter 6.
Analysis of samples from around the area to be dredged to the west of the jetty head indicates elevated concentrations of arsenic in MBH02 3.0-3.8m and MBH08 3.0m, and PCB25 at MBH08 3.0m. None of the samples analysed at depths above 2.5m showed elevated concentrations
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and therefore it is concluded that the dredge sediment arisings from this area are suitable for disposal at sea. We have consulted with Cefas as to our conclusions with respect to the arisings from the western/northern channel and they have confirmed that they are in agreement. However, they have indicated that where the dredge depth exceeds 2.5m the method of dredging must be chosen which will minimise the potential for over dredge and remobilisation of contaminated sediments identified at 3.0m. At present, it is proposed to use a suction dredger to dredge both the berth pocket and northern rear approach channel. This avoids re-suspension of the sediment directly when dredging but it is usual to allow the hopper to discharge overflow back into the water to maximise the amount of solids in the hopper. However, this practice creates a re-suspension of the solids and therefore in the area where the dredge depth in the northern approach is greater than 2.5m, we will impose a “no discharge overflow” requirement on the dredging contractor.
Our review and consultation with Cefas has indicated that all other dredge and pile arisings would be suitable for disposal at sea.
Land Disposal or Treatment
The results of the sample analysis (carried out by Hyder in June and August 2013) have been used to characterise the sediment in terms of waste for disposal to landfill. This assessment indicates that some of the sediment, at MBH02 1.0m, MBH03 (1.0m) and MBH08 (3.0m) may be characterised as hazardous, due to the concentrations of hydrocarbons. However, it may be that further characterisation indicates that this classification can be amended, or that the particular permit conditions for a landfill site allow acceptance of soil with these characteristics. The hazard assessment output sheets (from Hazwaste online) are included in Appendix 5-H.
In addition to the information obtained to date, the Principal Contractor who carries out the construction would be responsible, under UK waste management legislation, for properly characterising any waste and ensuring that it is reduced (through characterisation or treatment), reused or disposed of in a suitable manner. One sample (MBH03 2.5-3.0m) was analysed for the Waste Acceptance Criteria (WAC) determinands and this information will be of use to the Principal Contractor in initially identifying a suitable disposal site should the need arise.
Reuse
The results of the sediment analysis carried out to date have been reviewed with regard to possible reuse options, in particular on land. In order to provide an indication of whether the sediment may be suitable for reuse on residential or commercial property on land, the results have been compared to UK generic assessment criteria (GAC) for the protection of human health (Refs 5-18 and 5-19). The review of the leachability analysis results discussed in Section 5.4.4 concludes that the sediment is unlikely to pose a significant risk to controlled waters, although this risk will have to be assessed based on the proposed reuse location.
The concentrations of arsenic, benzo(a)pyrene and PCBs in several sediment samples are greater than the criteria for residential use with gardens, and in some cases residential use without gardens. Further analysis and assessment would need to be carried out to determine whether the sediment could be re-used for this purpose, based on the proposed use on the receiving site. It is possible that further standard totals and bioaccessibility (the proportion of the total concentration which would be absorbed by a human body) testing may show that the concentrations are less harmful than it would appear. The concentrations of arsenic found are not unusual in the slate geology of the southwest as natural concentrations are often high due to the mineralisation associated with metamorphosing processes.
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None of the soil/sediment concentrations exceed the GAC for commercial or industrial use sites. The soil arisings are therefore likely to be suitable for reuse on this type of site as soft landscaping or fill, again subject to site specific risk assessment.
Notwithstanding the above it should be noted that the arisings will have a high silt and saline content and therefore may not be suitable as an engineering soil or as a growing medium.
Discharge Consent Conditions There are no particular considerations with respect to water quality required when setting conditions for a discharge consent for activities during the construction phase at this site. 5.5.2 Decommissioning of Existing Jetty
Following construction of the new jetty the existing jetty will be demolished. There is potential for hazardous substances or waste materials to enter the watercourse. The following measures will be taken to minimise the potential for pollution of surface water and environmental impact from these activities;
• Empty and flush all fuel and sullage pipelines and any associated equipment. • Remove all equipment, buildings, tanks, pipework, etc. from the jetty head to barges for transport to commercial wharf for disposal/re-cycling. • Remove all pipelines, cables, ducting and pipe supports from the approach jetty to barges for transport to commercial wharf for disposal/re-cycling. • Demolish and dispose/re-cycle the redundant buildings and pipework on the land at the jetty root. • Demolish the existing jetty head, approach structure and mooring dolphins by cutting and breaking out the concrete deck and beam elements, using floating plant. • Piles to be cut off at or below existing seabed, using floating plant and ROVs or divers. This will minimise the amount of sediment disturbance during these activities. • Dispose of all materials by appropriate recycle or disposal method. • Measures will be put in place to contain all hazardous substances, demolition material and prevent waste materials falling onto the seabed or polluting the watercourse. There will be response procedures in place to ensure that any materials entering the watercourse are contained and recovered quickly to limit the impact caused. • Specific mitigation and waste management measures will be developed by the contractor carrying out the decommissioning work. The contractor will be required to comply with current UK guidance and best practice. 5.5.3 During Operational Phase
The proposed structure includes the storage and delivery of very large quantities of fuel, and the intake of fuel contaminated water from ships (as for the existing jetty).
The operation of the proposed fuel delivery jetty will include best practice and standard safety measures designed to minimise the potential for a pollution event. These will include:
• Secondary containment on the jetty head – see below • Real time pipeline/hose contents monitoring – see below • Intercepted drainage and bunding at foot of jetty and around filter beds – see below.
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• Emergency isolation valves (dual manual/automated) • Run-off water collection and disposal – see below. • Pressure monitoring and thermal relief (to guard against overheating of pipework). • Leak detection – see below. • Accumulators to regulate pressure in the pipelines. • Procedure for controlling the delivery of fuel, including communication between the fuel storage point and the jetty head. • Emergency procedures for containing leaks and spills. • Suitable equipment for containing leaks and spills, both on land and in the river.
Run-off Water Collection and Disposal
Rainwater that collects in the moats and other areas on site subject to potential fuel contamination is currently connected to an oil interceptor located below and adjacent to the crew car park near the existing jetty root. The interceptor is connected to a surface water discharge pipe that discharges to the river approximately halfway along the current jetty.
This project will collect any additional surface water and divert it through the above or new oil interceptor prior to discharge along the jetty approach span at or near the -2.5mbCD bathymetric contour.
There will be no run-off water collection to the mooring dolphins, jetty head and jetty approach span apart from the water that collects in the sumps situated below all joints and valves. Water that collects in these sumps will be extracted and discharged into the sullage pipe frequently as part of routine site management.
Drip Trays
Pipeline routing shall take into account the possibility of leakage from flanged connections and the need to prevent consequential pollution of the river, by the introduction of drip trays at these locations. Surface water and contaminants collected in the drip trays will be pumped into the sullage pipeline. All pipework on the approach jetty structure will be welded to prevent leakage and therefore does not require drip trays.
Landside Bunding
A bund shall be provided to the jetty side of the filtration station which shall be capable of containing a fuel spill from a pipe which has ruptured between the point at which the pipe exits the containment moat system and the bund itself. The bund will be capable of containing the volume of fuel/sullage likely to be discharged (based on the volume of pipework below the nearest cut off valve) with a 10% margin. All surface water that is collected within the bund shall be passed into an oil interceptor prior to discharge
Fuel Monitoring System
Fuel monitoring has two functions: a) A means of controlling and quantifying the issue and receipt of product; and b) A means by which the size of any possible fuel leakage can be reduced since product loss can be detected and appropriate actions undertaken to isolate the leak.
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The monitoring system shall be fully Supervisory Control and Data Acquisition (SCADA) compliant with monitoring capable from both the Jetty Head Control Office and the OPA offices near Thanckes OFD Main Gate.
Monitoring is to be undertaken via instrumentation on valves in the Jetty Head Manifold Area and on all valves located between the manifold area and the point of connection to the existing pipelines. 5.5.4 Decommissioning of Proposed Jetty (end of life)
The jetty has a design life of 60 years, assuming regular maintenance is undertaken. It is assumed that, at the end of its serviceable life the jetty will be dismantled in a similar manner to that described in Section 5.5.2. 5.6 Assessment of Effects
The following section provides an overall assessment of the risk posed by the proposed activities, based on the hazards identified and assuming implementation of the mitigation measures outlined above. Please refer to Tables 5-2, 5-3 and 5-7 for clarification of the assessment terms. 5.6.1 During Construction Phase
Marine Based Activities
Assuming that the mitigation measures described in Section 5.5 are in place, it is considered that the potential for water quality effects on the Tamar Estuary associated with marine based construction activities is restricted to the possibility of localised isolated sediment contamination, contained spills, and local sediment disturbance on a short term basis. The mitigation procedures in place will limit these to minor incidents and allow rapid remediation, with no significant impact to the wider area. The conceptual model and contaminated land risk assessment discussed in Section 5.4 concluded that the River Tamar is considered to be of ‘very high’ sensitivity, and that the potential risk posed to this receptor prior to mitigation measures being taken is moderate to low. This would be reduced through the implementation of the mitigation measures to low (refer to Table 5-7). The potential secondary impact on the ecology associated with the river is discussed in more detail in Section 6.
If the arisings from the dredging can be reused on another development near to the Site, then this may provide some environmentally beneficial effect.
As the Tamar Estuary is classified as a receptor of Very High sensitivity and the potential magnitude of construction phase effects is judged as Low , the overall effect is classified as having Temporary Slight Significance , in accordance with the matrix presented in Table 5-3.
Land Based Activities
Assuming that the mitigation measures described in Section 5.5 are in place, it is considered that the potential for water quality effects on the Tamar Estuary associated with land based construction activities is restricted to the possibility of localised, contained spills and/or silt releases during the construction phase. The mitigation procedures in place will limit these to minor incidents and allow rapid clean up, with no significant impact to the wider area.
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As the Tamar Estuary is classified as a receptor of Very High importance and the magnitude of construction phase effects is judged as Negligible , the overall effect is classified as having Temporary Slight Significance , in accordance with the matrix presented in Table 5-3. 5.6.2 During Decommissioning Phase (existing jetty)
The contractor that carries out the demolition work will be obliged to design and work to a method which will minimise the potential to pollute the watercourse, and which will include responsive measures which will enable any accident to be contained. In addition, all demolition materials will be recycled as far as possible, or suitably disposed of.
With these measures, the overall effect of the demolition of the existing jetty is a positive one since it will remove any potential for impact through leaks of hazardous substances from weathered infrastructure, and collapse into the watercourse.
As the Tamar Estuary is classified as a receptor of Very High importance and the potential magnitude of decommissioning phase effects is judged as Moderate Positive , the overall effect is classified as having Permanent Positive Moderate/Large Significance , in accordance with the matrix presented in Table 5-3. 5.6.3 During Operational Phase
During the operational phase there is limited potential for effects on the surface water environment. Once construction is complete on-site, land based activity will be considerably reduced with a corresponding reduction in the potential for the generation of silt-laden or contaminated runoff. The potential for water quality impacts is therefore limited to maintenance activities and pollution risk associated with the transport of fuel along the jetty and possible, rare use of fire fighting foam.
The scheme as a whole provides a beneficial environmental effect as the new and improved infrastructure will significantly reduce the potential for pollution incidents to occur.
As the Tamar Estuary is classified as a receptor of Very High importance and the magnitude of operation phase effects is judged as Moderate Positive , the overall effect is classified as having Permanent Positive Moderate/Large Significance , in accordance with the matrix presented in Table 5-3. 5.6.4 Decommissioning of Proposed Jetty (end of life)
The jetty has a design life of 60 years, assuming regular maintenance is undertaken. It is assumed that, at the end of its serviceable life the jetty will be dismantled in a similar manner to that described in Section 5.5.2. The effect is therefore expected to be similar to that outlined for decommissioning of the existing jetty, as described in Section 5.6.2. 5.7 Cumulative Effects
In Section 3.6 of this report, three proposed developments have been identified located within 2.5km of the site. These projects are located close to the banks of the Tamar Estuary and therefore there is potential for them to impact surface water quality if a pollution incident were to occur.
It is not known whether these projects include construction or dredging in the estuary. If so, and if these activities occurred at the same time as dredging operations at the Site, then there could be a cumulative impact on the water quality.
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The potential impact could be mitigated by co-ordination, through MMO, of dredging programmes. 5.8 Summary
This chapter is focussed on the potential for impact on surface water quality from contaminated sediment/soil due to the proposed construction and operational activities. Assessment of subsequent impact on ecological receptors is discussed in Chapter 6.
Information reviewed in order to establish the baseline conditions indicates that;
• historical and current potentially contaminative activities have been identified which could have impacted the water quality and the chemistry of the sediment and soils beneath the site,
• the water quality in the Tamar Estuary and Plymouth Sound is generally good but is impacted by elevated concentrations of tributyltin compounds. The chemistry and sediment load of the surface water is important because the estuary supports protected ecological systems,
• the chemistry of the sediments on the Site are consistent with conditions elsewhere in the Tamar Estuary.
Evidence of metals, PCB and PAH compounds were found as total concentrations in the sediment samples on the site, at concentrations sometimes above the lower limit criteria but below the upper limits. At one location arsenic and PCB were found at concentrations greater than the upper limits.
Neither of the two samples tested for leachability showed elevated concentrations of determinands compared to EQS. One sample showed notable but not significant concentrations of mineral oil which is likely to be partially representative of natural organic material.
The activities associated with the construction and ongoing operation of the proposed development, and the demolition of the existing jetty, with potential to cause impact to water quality are similar to those already carried out in the estuary.
Table 5-12 summarises the possible impacts from the proposed activities, the proposed mitigation measures, and an assessment of the residual significance of each activity whether positive or negative.
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Table 5-12 Water, Contamination and Sediment Quality - Impact Summary Table
Impact Description Temporary / Proposed Mitigation Measures Significance Rating Permanent
Construction Phase
Disturbance of sediment – Temporary Take additional precautionary Slight negative mobilisation of contaminants measures while working in any through dissolution, and/or locations identified as having additional sediment load elevated concentrations of contaminants Minimise as far as possible the extent of work requiring contact with the river bed. Ensure the contractor uses methods which will minimise sediment disturbance, sediment migration and arisings.
Deposition of sediment/soil arisings Temporary Where there will be an ecological Slight negative on the river bed (in terms of water effect then soil arisings will be quality) captured and disposed of off-site Minimise pile soil arisings volume
Storage, transport and use of Temporary Containment of hazardous Slight negative contaminative substances on land substances and over water – spill or leak to the Operational procedures including watercourse monitoring and control Emergency procedures and equipment
Run off of silt laden or Temporary Containment and removal of Slight negative contaminated surface water from soils the land Operational procedures including control of soil arisings
Decommission Phase (existing and proposed jetty)
Hazardous substances or foreign Temporary Removal of hazardous Slight negative materials entering the watercourse substances from the area before proceeding with the work Removal of all infrastructure to a suitable transfer station Suitable reuse/recycling and disposal of materials Responsive procedures and equipment to contain/recover any materials which enter the watercourse
Removal of worn infrastructure Permanent Removal, reuse/recycle of the Large positive old infrastructure which will reduce the potential for a pollution incident to occur
Operational Phase
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Storage, transport and use of Permanent Containment of hazardous Moderate positive contaminative substances on land substances and over water – spill or leak to the Operational procedures including watercourse monitoring and control Improved infrastructure will reduce Emergency procedures and the risk of pollution events and equipment therefore have a positive effect
Review of chemical analysis data indicates that waste sediment/soil arising from the site;
• should be suitable for disposal at sea, only with the exception of pile arisings from near to MBH08 located towards the northern end of the jetty head,
• may be characterised as hazardous for disposal on land. This has been identified at MBH03 and MBH08, and
• would be chemically suitable for reuse in a commercial or industrial setting, but may not be suitable for residential use. This is subject to further analysis and risk assessment depending on the intended reuse setting. Other properties of the waste may render it unsuitable e.g. engineering properties, saline content.
If these materials can be reused then there may be a positive environmental effect.
In conclusion – none of the potential effects identified are assessed as posing more than a slight negative effect following the implementation of the mitigation measures, and in some cases will have a positive effect in reducing the potential risk to the environment.
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6 ECOLOGY 6.1 Introduction
This chapter assesses the likely significant effects of the Thanckes OFD Loading Facility and Fire Fighting Upgrade in terms of terrestrial and marine ecology. The chapter details the impact assessment methodology that has been adopted and provides a current ecological baseline against which the predicted impacts of the proposed scheme are assessed. Mitigation measures are proposed, which will prevent the proposed Development from having a significant negative effect on the ecological receptors identified.
This chapter is supported by the information presented in Appendices 6A-F which present the results of the field surveys carried out to date and the HRA that has been undertaken.
This impact assessment has been undertaken in accordance with the guidance set out in the Institute of Ecology and Environmental Management’s (IEEM) Guidelines for Ecological Impact Assessment (2006) (‘the IEEM Guidelines’) (Ref 6-1), in order to provide CC and the MMO with “clear and concise information about the likely significant ecological effects associated with the project” (IEEM, 2006).
The terrestrial ecology surveys and desk study that underpin the ecological impact assessment were undertaken by Hyder Consulting in November 2012 and the marine ecology surveys were undertaken by Tamar Consulting in June and July 2013. 6.2 Regulatory and Policy Framework
This impact assessment has been undertaken in accordance with current international and national legislation, and national, regional and local plans and policies relating to nature conservation in the context of the proposed Development. A summary of the relevant legislation and policies, the requirements of these policies and the proposed Development response has been provided in Table 6-1 below.
Table 6-1 Ecology Regulatory and Policy Framework
Policy/Legislation Summary of Requirements Development Response
Conservation of The Regulations provide for the Species which are relevant to this Habitats and protection of both Special application include the following: Species Regulations Protection Areas (SPAs) and • Atlantic salmon ( Salmo salar ) – Feature 2010 (as amended)’ Special Areas for Conservation of Dartmoor SAC. (SACs) as part of the Natura • Allis shad ( Alosa alosa ) – Feature of 2000 network of protected areas Plymouth Sound and Estuaries SAC. across Europe. • Twaite shad ( Alosa falax ) – present in . the Plymouth Sound and Estuaries SAC The Regulations also provide but not at significant population levels. protection for European • Sea lamprey ( Petromyzon marinus ) - Protected Species (EPS) from present in the Plymouth Sound and the deliberate capture, killing or Estuaries SAC but not at significant disturbance. It is also an population levels. absolute offence to destroy or • damage the resting site or Harbour porpoise ( Phocoena phocoena ) breeding site of an EPS. – listed under Annex II of the Habitats Directive, EPS.
• Bottlenose dolphin ( Tursiops truncates )
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Policy/Legislation Summary of Requirements Development Response - listed under Annex II of the Habitats Directive, EPS. • Risso’s dolphin ( Grampus griseus – EPS. • Common dolphin ( Delphinus delphis ) – EPS. • Grey seal ( Halichoerus grypus) - listed under Annex II of the Habitats Directive. • Otter ( Lutra lutra ) – feature of Dartmoor SAC, EPS. • Overwintering avocet ( Recurvirostra avosetta ) – feature of Tamar Estuaries Complex SPA. • On-passage and overwintering little egret ( Egretta garzetta ) – feature of Tamar Estuaries Complex SPA. Habitats which are relevant to this application include the following: • Estuaries – primary reason for selection of Plymouth Sound and Estuaries SAC. • Intertidal mudflats – listed under Annex I of the Habitats Directive. A description of SACs and SPAs potentially affected by the proposed Development is included in Section 6.4. Potential ecological impacts are discussed in Sections 6.6 and 6.7, and the information to support a Habitats Regulations Assessment (HRA) is summarised in Annex F.
The Wildlife and The Act provides for the Eight SSSIs are located within 5km of the Countryside Act designation of Sites of Special proposed Development. A description of (1981) (as amended) Scientific Interest (SSSI), which SSSIs potentially affected by the proposed This Act is the are selected as the best national Development is included in Section 6.4. principle mechanism examples of habitat types, sites Potential ecological impacts are discussed in for the legislative with notable species and sites of Sections 6.6 and 6.7. protection of wildlife geological importance. No terrestrial species protected by the Act in England. Schedules 1-4 of the Act deal have been recorded within the terrestrial with the protection of wild birds. areas of the Site, although habitats were Schedule 5 of the Act details identified that were suitable to support such protection of other animal species. These include common species of species. Full protection is given reptiles and bats. It is considered likely that under Section 9 of the Act to otters use the intertidal habitats around the certain animals listed on Site. Schedule 5, including otters and Marine species listed on Schedule 5 all species of bats. Partial recorded within the study area are as protection under Section 9 is follows: given to certain other species, • Harbour porpoise including all common species of • reptile. Badgers are listed on Bottlenose dolphin Schedule 6 of the Act which • Risso’s dolphin
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Policy/Legislation Summary of Requirements Development Response outlaws certain methods of taking • Common dolphin or killing animals, where • Allis and twaite shad necessary. Schedule 8 of the These marine species are also listed in the Wildlife and Countryside Act Conservation of Habitats and Species details protection for plants and Regulations 2010 (as amended) and/or are fungi. listed as a feature of the Plymouth Sound Schedule 9 identifies non-native and Estuaries SAC. A description of the species that should not be baseline conditions with regard to marine introduced into, or spread in, the mammals and migratory fish are included in wild. Section 6.4. Potential ecological impacts are discussed in Sections 6.6 and 6.7.
Marine and Coastal Part 5 of this Act enables the Two MCZs are considered within this Access Act 2009 designation of Marine assessment; the Tamar Estuary MCZ and Conservation Zones (MCZs). the Whitsand and Looe Bay MCZ. The These are a type of Marine Tamar Estuary MCZ supports migratory Protected Area, which protect a European smelt ( Osmerus eperlanus ), which range of nationally important breed within the Tamar Estuary and the marine wildlife, habitats, geology native oyster ( Ostrea edulis ). Native oysters and geomorphology. MCZs exist are also listed on the OPSAR List of alongside European marine Threatened and/or Declining Species and Sites, SSSIs and Ramsar sites to Habitats. Blue mussel ( Mytilus edulis) beds form an ecologically coherent and European eel ( Anguilla anguilla ) are network of marine protected also present. areas. Further detail is included in Section 6.4 which describes the baseline, and Sections 6.6 and 6.7 which describe the potential ecological impacts of the proposed Development.
National Parks and LNRs are places with a wildlife or Woodland Wood Valley LNR and Budshead Access to the geological interest of local value Wood LNR are located approximately 4.5 Countryside Act that are capable of being and 4.9km to the north-east of the Site 1949 managed with the conservation respectively, within the city of Plymouth. Local Nature of nature and/or the maintenance Reserves (LNRs) are of public access as priority designated by Local concerns. Authorities under Section 21 of this act as amended by Schedule 11 of the Natural Environment and Rural Communities (NERC) Act 2006.
NERC Act (2006) The NERC Act places a duty Section 41 habitats and species recorded upon public bodies to consider within the study area include: conservation of biodiversity within • Intertidal mudflats all of their actions. Sections 40 • and 41 of this Act superseded Seagrass beds Section 74 of the Countryside • Sublittoral sediments Rights of Way (CRoW) Act. • Allis shad Section 41 lists flora, fauna and
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Policy/Legislation Summary of Requirements Development Response habitats considered by the • Twaite shad Secretary of State to be of • Atlantic salmon Principal Importance for • Sea trout ( Salmo trutta ) conserving biodiversity in • England. European smelt • European eel • Common dolphin • Risso’s dolphin • Harbour porpoise • Bottlenose dolphin • Otter A description of the baseline conditions with regard to these protected species and habitats are included in Section 6.4. Potential ecological impacts are discussed in Sections 6.6 and 6.7.
1992 OSPAR OSPAR is the mechanism by Habitats and species found in the vicinity of Convention for the which fifteen Governments, the proposed Development and included on Protection of the including the UK, of the western the OSPAR List of Threatened and/or Marine Environment coasts and catchments of Declining Species and Habitats are as of the North-East Europe, together with the follows: Atlantic European Community, cooperate • Atlantic salmon to protect the marine • European eel environment of the North-East • Atlantic. It begun in 1972 with the Allis and twaite shad Oslo Convention against • Intertidal seagrass beds dumping. It was broadened to • Native oyster cover land-based sources and • Thornback ray ( Raja clavata) the offshore industry by the Paris • Harbour porpoise Convention of 1974. These two conventions were unified, up- A description of the baseline conditions with dated and extended by the 1992 regard to these protected/notable species OSPAR Convention. An annex and habitats are included in Section 6.4. on biodiversity and ecosystems Potential ecological impacts are discussed in was adopted in 1998 to cover Sections 6.6 and 6.7. non-polluting human activities that can adversely affect the sea.
The Convention on This Convention was adopted in Species that have been recorded in the the Conservation of Bern, Switzerland in 1979, and vicinity of the proposed Development and European Wildlife came into force in the UK in are listed on the Bern Convention are as and Natural Habitats 1982. The principal aims of the follows: (the Bern Convention are to ensure • Atlantic salmon Convention, 1979) conservation and protection of all • Allis and twaite shad wild plant and animal species • and their natural habitats (listed Sea and river lamprey in Appendices I and II of the • Harbour porpoise Convention), to increase • Bottlenose dolphin cooperation between contracting All of these species are also listed in the parties, and to afford special Conservation of Habitats and Species protection to the most vulnerable Regulations 2010 (as amended) . A or threatened species (including
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Policy/Legislation Summary of Requirements Development Response migratory species). description of the baseline conditions with regard to these protected/notable species is included in Section 4. Potential ecological impacts are discussed in Sections 6.6 and 6.7.
Convention on the This Convention was adopted in Species that have been recorded in the Conservation of Bonn, Germany in 1979 and vicinity of the proposed Development and Migratory Species of came into force in the UK in1985. listed on the Bonn Convention are as Wild Animals (Bonn Contracting Parties work together follows: Convention or CMS, to conserve migratory species • Harbour porpoise 1979) and their habitats by providing • Bottlenose dolphin strict protection for endangered migratory species (listed in These species are also listed on the Appendix 1 of the Convention), Conservation of Habitats and Species concluding multilateral Regulations 2010 (as amended) . A agreements for the conservation description of the baseline conditions with and management of migratory regard to marine mammals is included in species which require or would Section 4. Potential ecological impacts are benefit from international discussed in Sections 6.6 and 6.7. cooperation (listed in Appendix 2 of the Convention), and by undertaking co-operative research activities.
National Planning The document streamlines Opportunities for the conservation and Policy Framework national planning policy into a enhancement of areas for biodiversity within (March 2012) consolidated set of priorities, with the proposed Development are considered the core theme being the delivery within the assessment. of sustainable development and economic growth. Paragraph 118 sets out how local planning authorities should aim to conserve and enhance biodiversity when considering planning applications.
UK Marine Policy Paragraph 2.3.2.1 states that Measures to avoid or mitigate any Statement (MPS) authorisation decisions that affect potentially adverse impacts as a result of the (March 2011) the UK marine area must be proposed Development are included within The MPS is the made in accordance with the the assessment. national framework relevant marine policy for taking decisions documents. In the case of the affecting the marine South West Region, where the environment Marine Plan is currently absent, ‘decisions must be made in accordance with the MPS’ . In considering marine ecology and biodiversity, Paragraph 2.6.1.3 of the MPS identifies that development should aim to avoid harm to marine ecology, biodiversity and geological conservation interests including
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Policy/Legislation Summary of Requirements Development Response through location, mitigation and consideration of reasonable alternatives. Where significant harm cannot be avoided, appropriate compensatory measures should be sought.
Biodiversity 2020: A Its aim is to halt the loss of Measures to avoid or mitigate any potentially Strategy for biodiversity, support healthy well- adverse impacts as a result of the proposed England’s Wildlife functioning ecosystems and Development are included within the and Ecosystem establish coherent ecological assessment. Services networks. It takes a landscape scale approach to conservation on both the land and at sea. It identifies the need to establish Local Nature Partnerships to deliver the Strategy through community involvement. It supports the establishment of Nature Improvement Areas, measures to increase the number of SSSI in favourable conservation status and the creation of a network of Marine Protection Areas. It also identifies that improvement and protection of the natural environment are part of the planning system and identifies that biodiversity offsetting will be piloted to deliver planning policy more effectively. It promotes flood and erosion management to conserve the natural environment and improve biodiversity.
Caradon Local Plan The policies of most relevance to See also response to the Conservation of First Alteration this chapter are: Habitats and Species Regulations 2010 (as (August 2007) CL1: Nature Conservation, amended).The Wildlife and Countryside Act Until a Local Plan for where development that affects and the NERC Act (all above), with respect Cornwall Council is sites of nature conservation to statutory designated sites and protected prepared, extant importance will not be permitted species. planning policies without adequate mitigation or Four non-statutory designated sites of within each District of the importance of the County importance to nature conservation the former County development overrides the known as County Wildlife Sites (CWS) are Council will continue significance of the site; found within 5km of the Site. These are: to form the basis of CL12: Sites of Special • Lower Lynher Estuary; planning decisions. Scientific Interest • St John’s Lake; (SSSI)/National Nature • Tincombe Reserve; Reserves (NNR), where • development that affects Clarrick and Pigshill Woods. SSSIs/NNRs will not be permitted The potential effects on the Lower Lynher without adequate mitigation or Estuary and St John’s Lake are considered in the context of the effects on the SAC and
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Policy/Legislation Summary of Requirements Development Response the importance of the SPA. development overrides the significance of the site. European designated sites will be given the same protection as SSSIs. CL13: Cornwall Nature Conservation Sites and Nature Reserves, where Development proposals which would adversely affect, directly or indirectly, locally designated Nature Conservation Sites, or the integrity or continuity of other landscape features of major importance to wild fauna or flora will only be permitted where: i) The reason for the development clearly outweighs the decrease in nature conservation value; ii) Any damage to the nature conservation interest is minimised; iii) Mitigating measures can be provided to protect remaining nature conservation and secure habitat creation or enhancement elsewhere within the site or local area. The policy applies to Areas of Great Scientific Value (AGSVs), Cornwall Nature Conservation Sites (CNCS), Regionally Important Geological Sites (RIGS), Local Nature Reserves (LNRs) as identified on the proposals map. CL15: The Coast, ‘In order to maintain the nature conservation value of the shoreline and adjoining coastal water, development which would cause physical damage, disturbance or pollution will not be granted planning permission.’ CL16: Protected Species , where development that would have an adverse effect on protected wildlife species will not
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Policy/Legislation Summary of Requirements Development Response be permitted without mitigation.
Cornwall Biodiversity The Cornwall Biodiversity Cornish Local Biodiversity Action Plan Action Plan (BAP) Initiative (CBI) produced the (LBAP) habitats and species recorded within Volume 4: Priority latest volume of Cornwall’s Local the study area include intertidal mudflats, Projects, Cornwall Biodiversity Action Plan in 2011. seagrass beds, estuarine rocky habitats, Biodiversity Initiative, This volume focuses on subtidal sands and gravels, otter, allis shad, 2011 landscape scale projects to twaite shad, Atlantic salmon, sea trout, achieve habitat targets and garden tiger moth, mouse moth. benefit a wider range of species Where impacts have been identified on than previous species specific species listed on the LBAP, mitigation has recovery projects. In addition, been proposed including timing of works and the CBI has published a new control of pollution. Cornish BAP list which contains 43 habitats and 360 species.
6.3 Methodology 6.3.1 Introduction
The methodology used to carry out the impact assessment is based upon the IEEM Guidelines for Ecological Impact Assessment. In accordance with the IEEM Guidelines, a detailed assessment has been carried out which attempts to collate all of the existing baseline information through a desk-based study and field surveys, and confidently predict all of the significant effects of the proposed Development on ‘Key Ecological Receptors’, with mitigation. Where significant adverse effects are predicted, the assessment presents detailed measures to mitigate these effects such that the residual effects of the proposed Development would not be significant.
In addition, measures have been developed to address the legislative and policy requirements associated with those protected species and valuable habitats for which significant effects are not expected, but which nevertheless warrant mitigation. Measures to enhance biodiversity in the area affected by the proposed Development and those which help to deliver Action Plan and local policy targets are also recommended. Although these have not been developed in response to significant effects, they do nevertheless contribute to the overall balance of effects on nature conservation for the proposed Development. This approach is considered to represent best practice. 6.3.2 The Study Area
The study area included the existing Thanckes OFD and habitats immediately adjacent (including intertidal and subtidal habitats) in order to investigate direct impacts on species and habitats. The study area was extended to investigate particular species and groups of conservation concern where appropriate, including the whole of the Plymouth Sound and Estuaries SAC, the Tamar Estuaries Complex SPA. Dartmoor SAC and the Tamar Estuary MCZ to investigate the potential impacts of habitat loss and the effects on overwintering and migratory birds and migratory fish. The study area also includes Whitsand and Looe Bay MCZ to assess the potential impacts associated with the disposal of dredged material at Rame Head disposal site.
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A desk-based assessment also collated ecological records for the Site itself and for the surrounding area up to a distance of 1km from the boundary of the Site. A distance of up to 10km was searched for European designated sites and 5km for bat species information.
The assessment area or Zone of Influence (ZoI) for ecology therefore extends to cover the Plymouth Sound and Estuaries SAC, the Tamar Estuaries Complex SPA and the Dartmoor SAC in addition to the terrestrial habitats of the existing Thanckes OFD and the intertidal mudflats in the immediate vicinity of the Site, which are not subject to any statutory designation. 6.3.3 Establishing Baseline Conditions
Desk Study
Ecological information relating to the study area (as defined above) was obtained from the Environmental Records Centre for Cornwall and the Isles of Scilly (ERCCISS) and bat records were requested from within a 5km search area. In addition, the Multi-Agency Geographical Information for the Countryside (MAGIC) website was reviewed for designated sites within a 5km search area, and for European sites within a 10km search area. The National Biodiversity Network (NBN) website (http://www.nbn.org.uk/ ), the Data Archive for Seabed Species and Habitats (DASSH) website ( http://www.dassh.ac.uk/ ) and the Marine Life Information Network (MARLIN) website ( http://www.marlin.ac.uk/ ) were all used to search for records of protected species. Detailed results of the desk-based assessment are included in Section 6.4.
The BTO provided Wetland Bird Survey (WeBS) core count (high tide) data for the count sector that included the Site (Tamar Estuary South) in addition to the Tamar Complex as a whole. This information consisted of tabulated five year synopses for the count sites, providing a range of average and peak counts for individual species observed. No recent low tide count data was available.
The Cornwall Bird Watching Preservation Society (CBWPS) was also contacted to obtain records within 500m of the Site. The only records that were available were BTO WeBs counts up to 2008 approximately 1km from the Site, however; more recent WeBs data had already been obtained from the BTO, therefore, this assessment uses the BTO data. Terrestrial Field Surveys
An initial extended Phase 1 Habitat Survey was undertaken on the 26 th and 27 th October 2009 of the jetty and the route of the existing fire main to identify any habitats or species which could constitute potential constraints to the proposed Development.
A further extended Phase 1 habitat survey was carried out on 8 th November 2012 of the whole Thanckes OFD, which involved identifying and mapping the dominant habitat types following standard Phase 1 habitat survey (Ref 6-2). Dominant plant species were noted, as were any uncommon species or species indicative of particular habitat types. Botanical names follow Stace, 1997 (Ref 6-3) .
The Phase 1 habitat survey was extended to involve a critical assessment of the value of the habitats present for their use by protected species or species of conservation concern, as outlined below:
• The value of the Site for invertebrates was assessed and any habitats or features of particular value were identified.
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• The value of the Site for reptiles and amphibians was assessed and any habitats or features of particular value for these species groups were identified. Great crested newts are considered to be absent in this part of Cornwall, thus these amphibians have not been included in this assessment. • The value of the Site for breeding birds was assessed. • An external inspection of all buildings, trees and other structures on Site was carried out to assess their suitability for occupancy by roosting and/or hibernating bats. Potential roost features were observed from the ground and scrutinised for their suitability to be used by bats, alongside searching for any evidence of use, such as staining, feeding remains or droppings. The likely value of the various habitat features for foraging and commuting bats was also critically assessed. • The Site was assessed for its potential to support dormice . • The Site was investigated for its use by badgers by searching for the characteristic signs of badger activity including setts, latrines, paths, footprints, hairs and feeding signs. Ornithology Surveys
Low- and high-tide wintering bird surveys were undertaken during the October 2009 site visit. A low-tide count was carried out as far as possible on the 26 th October 2009 between 14:30 and 16:30 hours. Due to poor weather conditions and low light levels, it was not possible to continue the low-tide count until the time of low water. Three count locations were used: the platform on the jetty looking back towards Wilcove to the north and Thanckes Lake to the south of the jetty, and two locations checking the extremities of the bays to the north and the south of the jetty that could not be observed from the jetty itself. Low-tide counts were made from the existing jetty at approximately 15 minute intervals, with half-hourly counts carried out at Wilcove and Thanckes Lake. In addition, a high-tide count was carried out on 27 th October 2009 between 09:15 and 11:45 using the same count locations and intervals as for the low-tide count. The results of the surveys are presented in Appendix 6-A. The results from the vantage points were verified and combined so that results are presented for two areas; Wilcove to the north, and Thanckes Lake to the south of the existing jetty. Also in Appendix 6-A is data obtained from the BTO with respect to core counts from the relevant count sector and the whole Tamar Estuary (for the five year period 2006/07-2010/11), and low tide counts from 2002/03. Marine Ecology Surveys
A sublittoral marine survey was conducted on the 18 th June 2013 in dry, clear weather by three surveyors on a chartered vessel collected from the Saltash Jetty at 09:30.
Drop-down video surveys were conducted using an underwater video camera on a frame with an umbilical cable back to the survey vessel in order to view images in real time. Video footage was also recorded along transects across the proposed and current dredge sites to allow a comparison between ‘before’ and ‘after’ states. Footage was also taken along Global Positioning System (GPS) referenced transects throughout the estuary for later analysis.
GPS referenced grab samples were collected using a Van Veen grab sampler (0.45m 2). The samples were taken to ground truth the video footage and confirm the sediment composition and species present. The number of samples taken was determined by the homogeneity of the sediment within the Site and the recommendation that single samples covering a wider area of interest is preferred over replicate sampling from smaller areas (Ref 6-4). All samples were retrieved from the seabed using a winch and were sieved through a fine mesh (0.5mm) sieve to dissipate fine sediment.
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Upon completion of fieldwork the video footage was analysed and the sieved grab samples identified to species level, where possible in order to identify marine biological habitats (biotopes) and ground-truth the video footage.
An intertidal survey was also undertaken on 12 th July 2013 in dry, clear weather with access to the jetty and foreshore on foot. The biotopes were mapped at the Site and across the foreshore either side of the proposed Development. Quadrat searches and core samples were conducted where possible to confirm biotope descriptions in accordance with the best practice methodology outlined below.
The marine surveys were conducted according to best practice as set out in the Marine Nature Conservation Review (MNCR) Rationale and Methods (Ref 6-5), the Marine Monitoring Handbook (Ref 6-6) and the Guidelines for the Conduct of Benthic Studies at Marine Aggregate Extraction Sites (Ref 6-4) as requested by CEFAS and the MMO. Classification of biotopes was conducted according to the Joint Nature Conservation Committee (JNCC) classifications of National Marine Habitat Classification for Britain and Ireland (Ref 6-7). 6.3.4 Assessing Effects
The significance of impacts is determined using the approach described in Chapter 3 of this ES. In accordance with the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (referred to as the ‘EIA Regulations 2011’), and the guidance set out in the IEEM Guidelines, it is considered inappropriate to attempt to investigate in detail all potential ecological issues in relation to the proposed Development. It is therefore necessary, under the Regulations, to focus on those activities that could potentially generate significant ecological effects on ‘Key Ecological Receptors’ thus our assessment has focussed on where there is the potential for significant effects to arise.
In order to determine the likelihood of a significant ecological effect, it is first necessary to identify whether a receptor is sufficiently valuable for a significant effect upon it to be material in decision-making. To achieve this, where possible, animal species and their populations have been valued on the basis of a combination of their rarity, status and distribution, using contextual information where it exists. Habitats and plant communities are evaluated against existing selection criteria, wherever possible (such as those developed to aid the designation of SSSIs or non-statutory designated sites). Only those receptors that it was considered could experience significant effects (i.e. impacts that could adversely affect the integrity of the habitat or the favourable conservation status of a species’ local population), and which were identified as being of sufficient value to be material to decision-making (i.e. of ‘District’ level importance or above), have been classified as being ‘Key Ecological Receptors’ and have been considered in the detailed assessment.
The habitats and features within the ZoI are known as the ‘ecological receptors’. The nature conservation importance/value of each of the ecological ‘receptors’ considers the protected species and species of conservation concern that they may support, to avoid pseudo- replication. For example, the importance for species associated with the intertidal mudflats (over-wintering birds) has been taken into account as part of categorising the overall importance/value of that feature.
The following geographic frame of reference has been used to determine the value of ecological receptors: International; National; Regional; County; District/Borough; and Parish/ Neighbourhood.
Those sites, habitats and/or species classified at ‘District/Borough’ level and above are considered to be sufficiently valuable for a significant effect upon them to be material in decision making. Where habitats and species within the Site do not constitute ‘Key Ecological Receptors’
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based upon their nature conservation value, and have not formed part of the detailed assessment, they still warrant consideration during the design and mitigation of the proposed development on the basis of their legal protection, their implications for environmental (and related) policies and plans, or other issues such as animal welfare issues. Therefore, consideration has separately been given to these ‘Other Ecological Receptors Requiring Mitigation’.
The results of the ecological valuation process are presented in Section 6.4 Baseline Conditions; this summarises the results of the desk study and field surveys, and identifies which of the resources are ‘Key Ecological Receptors’, which are ‘Other ecological receptors’ requiring mitigation, and those which have been scoped out of the assessment altogether. It is important to note that the selection of ‘Key Ecological Receptors’ has therefore been informed by an assessment not only of nature conservation value but also of the likely impacts upon them, the methodology for which is described below.
Impact Characterisation Once the ecological receptors within the ZoI have been identified and valued, it is then necessary to investigate potential impacts on those receptors in order to understand how they might be affected by the proposed Development.
The impact assessment has been based on an understanding of the likely activities associated with the proposed Development, the biophysical changes that could be predicted as a result of these activities, and the area over which such effects might be experienced by different receptors. These impacts have been considered for the construction, operational and decommissioning phases of the proposed Development. They have been characterised and described in Section 6.6 and possible mitigation measures identified.
Integration of impact characteristics An informed integration of each of these impact characteristics is necessary in order to underpin the determination of impact significance set out below.
Assessing significance The significance of an impact has been determined on the basis of an analysis of the factors that characterise the impact. An assessment is provided of the confidence of this assessment in line with the information provided in Table 6.2 below. The nature conservation value of significantly affected receptors has then been used to guide further mitigation and related measures and help interpret the significance of residual impacts.
Table 6-2 Assessment of significance
Definition
Significant negative impacts on a feature of international value , inhibiting the delivery of conservation objective(s) for a European site or the restoration to favourable status of a feature of European importance Significant negative impact on a feature of national value , inhibiting the delivery of conservation objective(s) for SSSI (or equivalent) or the habitats and species of Principal Importance for the conservation of biodiversity in England, as listed under Section 41 of the NERC Act (2006) Significant negative impact on a feature of county value , inhibiting the delivery of conservation objective(s) for sites of county importance; or county Development Plan Policy (or equivalent), or county Biodiversity Action Plan objective(s)
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Definition Significant negative impact on a feature of district/borough value, inhibiting the delivery of Local Development Plan Policy (or equivalent) or local UK Biodiversity Action Plan objective(s) No significant impact
Significant positive impact on a feature of district/borough value, promoting the delivery of Local Development Plan Policy (or equivalent) or the habitats and species of Principal Importance for the conservation of biodiversity in England, as listed under Section 41 of the NERC Act (2006) Significant positive impact on a feature of county value , promoting the delivery of conservation objective(s) for sites of county importance; or county Development Plan Policy (or equivalent), or county Biodiversity Action Plan objective(s) Significant positive impact on a feature of national value , promoting the delivery of conservation objective(s) for SSSI (or equivalent) or UK Biodiversity Action Plan objective(s) Significant positive impacts on a feature of international value , promoting the delivery of conservation objective(s) for a European site or the restoration to favourable status of a feature of European importance
6.3.5 Consultation
Following submission of a Scoping Report and HRA Screening to CC in December 2012, responses have been received from the MMO, NE, the EA and CC with respect to the scope of the ecological assessment and the HRA Screening. The main points raised are identified in the table below, with a response provided.
Table 6-3 Consultation responses
Consultee Summary response Measures taken to address this response MMO Need for further benthic Benthic surveys undertaken. Detailed results surveys contained within Appendix 6-C Impacts on marine ecology Detailed assessment of potential impacts on receptors from the release of key ecological receptors contaminated sediments and smothering from increased suspended sediments Assessment of habitats and Detailed assessment of potential impacts on species listed on OSPAR List key ecological receptors of Threatened and Declining Species and Habitats MMO confirmed that there was No separate MCZ assessment has been no need for a separate MCZ produced. Potential impacts on MCZs are assessment report in a considered within this Ecology chapter conversation on 25 th September 2014 NE Potential impacts on migratory Detailed assessment of potential impacts on fish through underwater migratory fish as a key ecological receptor, vibration including commissioning a report by Subacoustech Environmental into the underwater noise impact during construction on migratory fish species. This report was reviewed by NE and Cefas and, following this review, it has been agreed that percussive piling will restricted to the months of September to March (i.e. no percussive piling between 1st April and 31st August), outside the main migratory fish period, to avoid
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disturbance to the EPS allis shad and Atlantic salmon. There are no timing restrictions with regard to vibro-piling, pile case oscillation and augering/drilling, subject to monitoring of initial operations outside of the key sensitive window of April to August to ensure that noise levels are within the levels predicted. Cefas are in agreement with this response. Loss and damage to SAC, Detailed assessment of potential impacts on SPA and SSSI features key ecological receptors Insufficient information HRA Screening Report provided in Appendix provided to undertake a Test of 6-D Likely Significant Effect EA Map and survey habitats under Intertidal and subtidal surveys undertaken. the development footprint Detailed results contained within Appendix 6-C Benthic surveys required Benthic surveys undertaken. Detailed results contained within Appendix 6-C Piling and dredging must be See response above regarding piling. it is carried out between December recommended that Dredging will take place and March between and March. Proposals to protect, restore The overall purpose of the proposed and enhance nature Development is to upgrade and modernise an conservation ageing oil fuel depot/refuelling jetty and pipeline/fire-fighting system to make it safer, substantially reducing the risk of accidents, including pollution incidents. Mitigation measures aim to protect the key ecological receptors. It is anticipated that areas of seabed affected will be allowed to re- colonise naturally, but this will be encouraged by removing crabbing tiles from the intertidal area within the DIOs control, and reducing the amount of crabbing and bait digging in the area by installing new signage to discourage these activities.
6.3.6 Limitations and Assumptions
The terrestrial survey results used to inform the baseline conditions were from 2012. However, no significant ecological constraints were identified at this time and it is considered that the habitats are stable and unlikely to change. Nevertheless, it is anticipated that pre-construction surveys will be undertaken to confirm the continued absence of protected species within the foot print of the Development.
The marine survey results used to inform the baseline conditions were from 2013. The marine habitats are relatively stable and are unlikely to have changed in the interim period.
Since undertaking the marine surveys, the proposals have changed. However, the area surveyed effectively covered the revised Development footprint.
The low-tide wintering bird count carried out on the 26 th October 2009 was curtailed due to poor weather conditions and low light levels. However, it is considered that sufficient information was collected in order to inform the baseline conditions.
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6.4 Description of the Baseline Conditions
The baseline conditions have been established through a desk-based assessment and field surveys as described previously. The results are presented below, with a Phase 1 map of the Site (Drawing 6-1) and accompanying Target Notes provided in Appendix 6-B. A map illustrating the designated sites in the vicinity of the Site is presented in Drawing 6-2. The detailed results of the marine surveys are presented in Appendix 6-C. 6.4.1 Site Description
The terrestrial part of the Site occupies the slopes of a promontory jutting out into the Tamar Estuary and comprises a series of level terraces on which fifteen fuel storage tanks were situated, along with an extensive network of pipelines, pumps, filtration equipment and containment moats. Surrounding the fuel storage tanks are large areas of short mown amenity grassland with a fringe of semi-natural broadleaved woodland along the shore line.
The existing Yonderberry Jetty lies on the Hamoaze (the estuarine stretch of the River Tamar between the River Lynher and Plymouth Sound). The jetty approach is 254m x 5.8m and the jetty head is 61m x 9m. The jetty comprises a bridge structure on piles connecting the jetty head to the OFD and holding a pipe rack and walkway. The jetty head is also supported by piles and there is an existing berth pocket alongside the jetty head, which is maintained by a maintenance dredging regime. The walkway and jetty piles traverse through the intertidal habitat extending to the subtidal habitats of Tamar Estuary. There are also three mooring dolphins, two to the south of the jetty and one to the north, all situated in subtidal habitat. 6.4.2 Statutory Designated Sites
Plymouth Sound and Estuaries SAC
The subtidal habitats within the Site fall within the Plymouth Sound and Estuaries SAC. The SAC is a large (6402ha) marine inlet comprising the estuaries of the rivers Tamar, Lynher and Tavy. The River Tamar and its tributaries provide the main input of fresh water into the estuary complex, and form a ria (drowned river valley) with Plymouth lying on the eastern shore. The broader lower reaches of the rivers form extensive tidal mudflats bordered by saltmarsh communities. The mudflats contain extensive and varied infaunal communities rich in bivalves and other invertebrates, and provide feeding grounds for waterbirds in numbers of European importance. Saltmarshes provide important feeding and roosting areas for large numbers of wintering and passage waterbirds.
Annex I habitats that are a primary reason for selection of the SAC are as follows:
• sandbanks which are slightly covered by sea water all the time;
• estuaries;
• large shallow inlets and bays;
• reefs; and
• Atlantic salt meadows ( Glauco-Puccinellietalia maritimae ).
The Annex I habitats present as a qualifying feature, but not a primary reason for selection of the SAC are: mudflats and sandflats not covered by seawater at low tide.
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The conservation objectives for the estuaries feature of Plymouth Sound and Estuaries SAC are as follows:
Subject to natural change, maintain the estuaries in favourable condition, in particular:
• Intertidal mud communities;
• Subtidal mud communities;
• Intertidal mixed muddy sediment communities;
• Subtidal mixed muddy sediment communities;
• Estuarine bedrock, boulder and cobble communities;
• Subtidal sandbank communities;
• Saltmarsh communities;
• Reedbed communities.
As such, the habitats that would be affected are considered to come under this primary reason for SAC selection.
The Annex II species that is a primary reason for selection of the SAC is: Shore Dock ( Rumex rupestris ). However, this species occurs on rocky shore habitats above the mean high water mark and has not been found during surveys of the Site. This species is not considered further in this assessment.
The Annex II species present as a qualifying feature, but not a primary reason for site selection is allis shad .
Also listed on the SAC Natura 2000 data form (Ref 6-8) as being present (but not at qualifying population levels) are the following Annex II species:
• sea lamprey
• river lamprey
• twaite shad
• bottlenose dolphin
• harbour porpoise
• otter
• grey seal
The effects on the migratory fish and marine mammals listed above will be considered in detail under the ‘migratory fish’ and ‘marine mammals’ key receptors respectively. Otters are known to be present along the Tamar Estuary but the Site is not considered to be of particular value to otters given the lack of desk study records and the sub-optimal nature of the habitat within the Site. Nevertheless, otters are likely to commute up and down the estuary and any effects on them will be considered on account of their legal protection.
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Given the considerable distance between Rame Head disposal site and this SAC, no impacts as a result of sediment disposal at sea are envisaged. This is supported by a letter from NE dated 17 th January 2014 (Ref 105344, MLA/2013/00432) in relation to the current maintenance dredging licence which states: NE can confirm that the Rame Head marine disposal site is not located within or in close proximity to any SAC, SPA or Ramsar .
Due to the nature conservation value of this site and the species it supports, the Plymouth Sound and Estuaries SAC is considered to be of International importance.
More information regarding the potential impacts on this European site can be found in Appendix 6-D the HRA Screening Report.
Tamar Estuaries Complex SPA
The Tamar Estuaries Complex SPA is 1955 ha in size, located approximately 1.4km south of the Site. This SPA qualifies under Article 4.1 of the Directive (79/409/EEC) by supporting populations of European importance of the following species listed on Annex I of the Directive:
• little egret ( Egretta garzetta ) on passage, and
• avocet ( Recurvirostra avosetta ) during the winter
As a result of the SPA Review process undertaken in 2001, over-wintering little egret (42 individuals at least 8.4% of the British population) was added to the published information for the site. Although not yet legally classified, Natural England’s website (www.naturalengland.org.uk ) states that these sites are ‘… as a matter of Government policy treated in the same way as classified features. ’ The value of the Site for over-wintering little egret will therefore be considered in the assessment (see paragraphs below).
Avocet
Core count (high-tide) data provided by BTO (from 2006/7-10/11) revealed that no avocet have been recorded from the Tamar Estuary (South) Sector 10 (within which the Site is located) for at least five years. The most recent low tide count dot distribution map provided by BTO (Figure 6- 1) indicates that avocet are not found within 3km of the Site, as they winter on the upper reaches of the Tamar-Tavy Estuary. In addition, of the three underlying SSSI designations, wintering avocet are only a feature of the Tamar-Tavy Estuary SSSI (located approximately 3.2km to the north of the Site) and are not a feature of either the Lynher Estuary SSSI or St John’s Lake SSSI, both of which are closer to the proposed Development. It is considered therefore that there will be no adverse impact on this species as a result of the Development, and it will not be considered further in this assessment.
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Figure 6-1: Distribution of avocet within the Tamar Estuaries Complex SPA at low tide 2002/03
Thanckes jetty
Little egret
Table 6-4 (extracted from information provided in Appendix 6-A) provides a comparison of bird survey results with BTO count data.
Table 6-4 BTO WeBS data compared with October 2009 survey results
BTO WeBS data Wilcove (north of jetty) Thanckes Lake (south of jetty) Species High-tide count data High-tide Low-tide High-tide Low-tide from the Tamar Estuary Complex: 5 year (2006/7-10/11) autumn mean peak Little egret 103 2 3 0 2
Table 6-4 illustrates that, from the bird survey undertaken in October 2009 (during the autumn passage period), the area to the north of the jetty (Wilcove) recorded a maximum of two little egrets at high tide, 1.94% of the five year autumn mean peak high-tide count data for the Tamar estuary as a whole (2006/7-10/11). For Thanckes Lake to the south of the jetty no little egrets were recorded at high tide.
With respect to low tide counts, three little egrets were recorded at Wilcove and two were observed at Thanckes Lake. There is no comparable data available from the BTO, however; as low tide counts undertaken by the BTO are undertaken from November to February (winter period).
Although the habitats around the existing jetty are not part of a designated SPA, they are clearly functionally linked to the SPA habitats and support on-passage little egrets which are an SPA feature.
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No surveys were undertaken during the wintering period, therefore BTO core count and low tide data has been used to assess the importance of the intertidal habitats within and adjacent to the Site for little egret.
Figures 6-2 and 6-3 below (taken from BTO website www.bto.org ) illustrate the areas covered by the BTO WeBS in the Tamar Estuary. For the five year period (2006/7-10/11) a mean peak of five little egret were recorded in the Tamar Estuary (South) Sector 10 (illustrated in Figure 6- 2). This sector covers an area of approximately 390 ha and extends north from the Site to the Tamar Bridge (approximately 3km away) and south to Torpoint ferry crossing, a distance of approximately 940m. The Tamar Complex as a whole covers an area greater than the SPA (which is 6402.03ha) and recorded a mean peak of 73 little egrets over the same time period.
Figure 6-2 Tamar Estuary (South) Sector 10
Thanckes jetty
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Figure 6-3 Tamar Complex
Thanckes jetty
The BTO data, indicates that fewer little egrets are recorded over winter than during passage. The October 2009 bird survey was undertaken during the peak passage period and a maximum of two little egrets were observed in the vicinity of the Site. It is therefore considered that the Site is unlikely to support significant numbers of overwintering little egret. This conclusion is supported by Figure 6-4 which illustrates the distribution of little egret at low tide during the winter of 2002/3. It can be seen that no little egret were observed to the north of the jetty, and only a small number to the south of the jetty on Thanckes Lake.
Figure 6-4 Distribution of little egret at low tide, winter 2002/3
Thanckes jetty
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Notwithstanding these data, the potential impacts on any little egret that may be using the habitats in the vicinity of the Site (which are functionally linked to nearby SPA habitats) will be considered further in Section 6.6.
Given the considerable distance of the Rame Head disposal site from this SPA, no impacts as a result of sediment deposition here are envisaged. This is supported by a letter from NE dated 17 th January 2014 (Ref 105344, MLA/2013/00432) in relation to the current maintenance dredging licence which states: NE can confirm that the Rame Head marine disposal site is not located within or in close proximity to any SAC, SPA or Ramsar .
Due to the nature conservation value of this site and the species it supports, the Tamar Estuaries Complex SPA is considered to be of International importance.
More information regarding the potential impacts on this European site can be found in Appendix 6-D the HRA Screening Report.
Plymouth Sound and Estuaries European Marine Site The conservation objectives for a European site are intended to represent the aims of the Habitats and Birds Directives in relation to that site. The marine components of the Plymouth Sound and Estuaries SAC and the Tamar Complex SPA qualify as European Marine Sites, however; for simplicity, NE have provided the conservation objectives for both the SAC and SPA components as a single European marine site: the Plymouth Sound and Estuaries European Marine Site. The conservation objectives are summarised within Appendix 6-E. The conservation objectives for the marine site focus on the area, range, structure and function of habitats, to ensure that they are in a stable and suitable condition to support the species and features for which the site is designated. Specific conservation objectives are also included for the birds listed as qualifying features relating to habitat condition in recognition that bird populations may change as a reflection of national or international trends or events.
The European Marine Site is considered vulnerable to a range of human activities, including physical loss and damage, disturbance, and toxic and non-toxic contamination.
Dartmoor SAC
The Site is located approximately 10km to the south-east and downstream of Dartmoor SAC. This SAC comprises areas of blanket bog, heathland and woodland. However, its qualifying features include Atlantic salmon, which reach Dartmoor SAC via the Plymouth Sound and Estuaries SAC.
Annex I habitats that are a primary reason for selection of the SAC are as follows:
• northern Atlantic wet heaths with Cross-leaved Heath ;
• European dry heaths;
• blanket bogs;
• old sessile oak woods.
None of these Annex I habitats occur in the vicinity of the Site and there are no impact pathways linking the Site to the habitats. Consequently no impacts on the habitats are predicted and they will not be considered further in this assessment.
The Annex II species that is a primary reason for selection of the SAC is southern damselfly. However, this species is found at a single valley mire at 280m altitude and is therefore not found
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anywhere close to the Site. It is considered that the proposed Development would not affect the habitats that support this species and therefore it is not considered further in this assessment.
The Annex II species present as a qualifying feature, but not a primary reason for site selection are Atlantic salmon and otter . It is feasible that otters associated with this SAC may come down as far as the Tamar. Otters are known to be present along the Tamar Estuary and are listed as being present within Plymouth Sound SAC but not in significant numbers. The Site is not considered to be of particular value to otters given the lack of desk study records, the sub- optimal habitat within the Site and the large home ranges of otters. Nevertheless, otters are likely to commute up and down the estuary and any effects on them will be considered on account of their legal protection.
Given the considerable distance of the Rame Head disposal site from this SAC, no impacts as a result of sediment deposition here are envisaged. This is supported by a letter from NE dated 17 th January 2014 (Ref 105344, MLA/2013/00432) in relation to the current maintenance dredging licence which states: NE can confirm that the Rame Head marine disposal site is not located within or in close proximity to any SAC, SPA or Ramsar .
The only SAC feature that will be considered in this assessment is Atlantic salmon, specifically the effects on salmon migrating past the proposed Development. The effects on Atlantic salmon will be considered in detail in this assessment under the ‘migratory fish’ key receptor. Dartmoor SAC is considered to be of International importance.
More information regarding the potential impacts on this European site can be found in Appendix 6-D the HRA Screening Report and Section 6.6 of this assessment.
Lynher Estuary SSSI
Lynher Estuary SSSI, located approximately 2km to the west of the Site is also part of the Plymouth Sound and Estuaries SAC and the Tamar Estuaries Complex SPA (the Plymouth Sound and Estuaries European Marine Site). It is designated for its saltmarsh and mudflat communities, which provide important feeding and roosting grounds for large populations of wintering wildfowl and waders including wigeon ( Anas penelope ), teal ( Anas crecca ), curlew (Numenius arquata ) and dunlin ( Calidris alpina ). The ancient woodlands of Sheviock and Wacker are also included in the site. Due to the lack of impact pathways and distance from the Site, the saltmarsh and woodland will not be considered further in this assessment.
Due to its nature conservation value and the species it supports, the Lynher Estuary SSSI is considered to be of National importance. Impacts on the mudflat habitats the site supports are considered in the context of the European Marine Site. Bird species associated with this SSSI are considered along with birds associated with the Tamar Estuaries Complex SPA and the St John’s Lake SSSI (see below) as a single key ecological receptor.
St John’s Lake SSSI
St John’s Lake SSSI, located approximately 1.4km to the south of the Site is part of the Plymouth Sound and Estuaries SAC and the Tamar Estuaries Complex SPA. It is designated for its extensive intertidal mudflat communities, which provide important feeding and roosting grounds for large populations of wintering wildfowl and waders, including nationally important populations of wigeon and black-tailed godwit ( Limosa limosa ).
Due to its nature conservation value and the species it supports, St John’s Lake SSSI is considered to be of National importance. Impacts on the mudflat habitats the SSSI supports are
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considered in the context of the European Marine Site. Bird species associated with this SSSI are considered along with birds associated with the Tamar Estuaries Complex SPA and the Lynher Estuary SSSI (see above) as a single key ecological receptor.
Tamar-Tavy Estuary SSSI
Tamar-Tavy SSSI, located approximately 3.2km to the north of the Site at its closest point, is part of the Plymouth Sound and Estuaries SAC and the Tamar Estuaries Complex SPA. It is designated for its nationally important wintering population of avocet and estuarine habitats, including intertidal mudflats and saltmarsh. Several areas of semi-natural woodland also form part of the site and the freshwater section of the estuary supports Triangular Club-rush and kingfisher.
Due to its nature conservation value the Tamar-Tavy Estuary SSSI is considered to be of National importance. The distance upstream from the Site means that there is little opportunity for an impact pathway between the SSSI and the proposed Development, therefore no impacts are predicted on the Tamar-Tavy Estuary SSSI and it will not be considered further in the impact assessment.
Plymouth Sound Shores and Cliffs SSSI
A section of Plymouth Sound Shores and Cliffs SSSI is 4.9km to the south of the Site, with the majority of this SSSI approximately 5.4km to the south-east of the Site. This SSSI encompasses ecological zones from the open coast and sheltered bay parts of Plymouth Sound, and includes shore communities with a south-western influence. The SSSI forms part of the Plymouth Sound and Estuaries SAC and is considered to be of National importance. However, due to the distance from the Site and lack of impact pathways to the woodland and freshwater sections of the SSSI, the species associated with these features will not be considered further. In addition, the distance from the Site means that any potential impacts from increased sediment discharge as a result of works will not be significant so far downstream, therefore the Plymouth Sound Shores and Cliffs SSSI will not be considered further in this impact assessment.
Mount Wise SSSI
Mount Wise SSSI is located approximately 2.5km south-east of the Site, and is designated for its geological interest. Given the absence of impact pathways linking this SSSI to the Site, and its nature as a geological SSSI it is considered unlikely that the Development would have direct or indirect effects on this site of National importance. Mount Wise SSSI will not be considered further within the impact assessment.
Western King SSSI
Western King SSSI is located approximately 3.5km to the south-east of the Site, and is designated for its geological interest and area of amenity grassland and scrub which support colonies of the nationally rare plant Field Eryngo (Eryngium campestre) . Given the distance from the Site and the lack of impact pathways linking to this SSSI, it is considered unlikely that the Development would have direct or indirect effects on this site of National importance. Western King SSSI will not be considered further within the impact assessment.
Richmond Walk SSSI
Richmond Walk SSSI is located approximately 3.3km south-east of the Site, and is designated for its geological interest. Given the absence of impact pathways linking this SSSI to the Site, and its nature as a geological SSSI it is considered unlikely that the Development would have
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direct or indirect effects on this site of National importance. Richmond Walk SSSI will not be considered further within the impact assessment.
Kingsand to Sandway Point SSSI
Kingsand to Sandway Point SSSI is located approximately 4.9km south of the Site, and is designated for its geological interest. Given the absence of impact pathways linking this SSSI to the Site, and its nature as a geological SSSI it is considered unlikely that the Development would have direct or indirect effects on this site of National importance. Kingsand to Sandway Point SSSI will not be considered further within the impact assessment.
Tamar Estuary Marine Conservation Zones (MCZ)
The Tamar Estuary MCZ is located in two separate areas including the upper reaches of the Tamar and Lynher estuaries, and is part of the Plymouth Sound and Estuaries SAC, the Tamar Estuaries Complex SPA, the Lynher Estuary SSSI and the Tamar-Tavy Estuary SSSI. The proposed Development is approximately 2km away from this MCZ, at its closest point within the Lynher estuary. The Tamar Estuary MCZ supports intertidal biogenic reefs and intertidal coarse sediment, as well as migratory European smelt, which breed within the Tamar Estuary, and European eel. It is also designated due to the presence of the native oyster and blue mussel beds. Due to its nature conservation value and the species it supports, the Tamar Estuary MCZ is considered to be of National importance.
It is unlikely that the proposed Development will have a significant effect on intertidal biogenic reefs, intertidal coarse sediment, oysters or blue mussel beds within the MCZ given that the control of sediment release from dredging will avoid the effects of fine sediment re-deposition and associated pollution over such a distance. (See Table 6.5 for further information regarding marine habitats within the study area.)
The only features that will be considered in this assessment are European smelt and European eel, specifically the effects on these species migrating past the proposed Development. The conservation objective for European eel is ‘maintain’ and for European smelt is ‘recover’. The effects on European smelt and European eel will be considered in detail in this assessment under the ‘migratory fish’ key receptor.
Rame Head and Whitsand Bay SSSI
The site extends for approximately 8km along the south Cornwall coast, located approximately 1.5km north of the Rame Head disposal site. The coastal cliff habitats are of particular importance for the occurrence of the largest colony of the nationally rare Shore Dock. In addition, the site also supports significant populations of other rare plant species including the nationally rare Slender Bird’s-foot-trefoil ( Lotus angustissimus ) and Early Meadow-grass ( Poa infirma ). Whitsand Bay is also of special interest for its geology and coastal geomorphology.
Given the lack of impact pathways between SSSI, which is designated on account of its terrestrial features, and Rame Head disposal site, it is considered unlikely that the Development would have direct or indirect effects on this site of National importance. Rame Head and Whitsand Bay SSSI will not be considered further within the impact assessment.
Whitsand and Looe Bay MCZ
The Whitsand and Looe Bay MCZ is an inshore site located off the south coast of Cornwall approximately 5.2km from the proposed Development across land, but approximately 10km from the proposed Development by sea, around Rame Head. The site supports intertidal sand
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and coarse sediment habitats, subtidal sand and coarse sediment habitats, as well as intertidal rocky habitats at Hannafore and on Looe Island which support a high diversity of seaweeds and invertebrates. The ocean quahog ( Arctica islandica ), a long-lived bivalve which is known to live for over 400 years has been recorded within sediment habitats in the site. Within the shallower part of the site the seagrass beds are likely to provide a nursery ground for ecologically and commercially important species such as cuttlefish ( Sepia officinalis ). Further out to sea there are shipwrecks and small areas of subtidal rocky reef that support pink sea-fans ( Eunicella verrucosa ) and rare sea-fan anemones ( Amphianthus dohrnii ). Stalked jellyfish ( Haliclystus auricular ) are also present within the site. Due to its nature conservation value and the species it supports, the Whitsand and Looe Bay MCZ is considered to be of National importance.
A potential impact pathway exists between the Site and this MCZ via the Tamar River and the sea around Rame Head. However, given the considerable distance of this impact pathway and the control of dredging operations, no impacts are envisaged on this MCZ as a result of the proposed Development. This MCZ will not be considered further in this assessment.
Woodland Wood Valley LNR
Woodland Wood Valley LNR is located approximately 4.9km to the north-east of the Site. It is a valuable landscape and biodiversity resource for the surrounding urban area and includes a variety of habitats including woodland, hedgerows, meadows and a stream. The LNR has no links with the Site and it is considered that the proposed Development would have no direct or indirect impacts on this site of County importance. Woodland Wood Valley LNR will not be considered further in this assessment.
Budshead Wood LNR
Budshead Wood LNR is situated approximately 4.5km to the north-east of the Site, surrounded by urban development. It is ancient woodland adjacent to a tidal creek that runs into the Tamar. It is considered that the distance from the Site is sufficient that no impact pathway can connect the Site to the tidal creek that is adjacent to the LNR, a site of County importance. As a result, Budshead Wood LNR will not be considered further in this assessment. 6.4.3 Non-statutory designated sites
The mudflats adjacent to the shore, within the site, are within an AGSV (See Planning Policy CL13 within the Caradon Local Plan First Alteration (August 2007) in Table 6-1). These represent a broader approach to nature conservation than the protection of specific sites and act as provide a buffer around the most important and sensitive nature conservation sites, providing links between protected sites, facilitating the movement of wildlife. This site of County importance considered under the ‘seagrass beds’ ecological receptor.
Four CWS are found within 5km of the Site. These are as follows:
• Lower Lynher Estuary;
• St John’s Lake;
• Tincombe Reserve;
• Clarrick and Pigshill Woods.
The Lower Lynher Estuary CWS and St John’s Lake CWS are in excess of 2km from the Site. They are designated on account of the saltmarsh habitat they support. Given the distances involved, it is considered unlikely that the Development would have any direct or indirect effects
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the saltmarsh habitat within these sites of County importance, and they are not considered further in this assessment.
Tincombe Reserve CWS is a small woodland approximately 3km to the north-west of the Site close to the centre of Saltash. Given the distance from the Site and the lack of impact pathways linking to this CWS, it is considered unlikely that the Development would have direct or indirect effects on this site of County importance. Tincombe Reserve CWS will not be considered further within the impact assessment.
Clarrick and Pigshill Woods CWS are situated approximately 3.5km to the south of the Site. Given the distance from the Site and the lack of impact pathways linking this CWS to the Site, it is considered unlikely that the Development would have direct or indirect effects on Clarrick and Pigshill Woods CWS. Therefore, Clarrick and Pigshill Woods CWS will not be considered further within the impact assessment.
Churchdown Farm Community Nature Reserve
The Cornwall Wildlife Trust manages this farm as a Community Nature Reserve for the benefit of wildlife. The reserve is approximately 2.7km north of the Site, and given the absence of impact pathways linking the reserve with the proposed Development, it is considered unlikely that the Development would have direct or indirect effects on this Community Nature Reserve of Parish/Neighbourhood value. Churchdown Farm will not be considered further within the impact assessment. 6.4.4 Terrestrial plants and habitats
The Site occupies the slopes of a promontory jutting out into the Tamar Estuary and comprises a series of level terraces on which the fuel tanks are situated. Drawing 6-1 illustrates the results of the Phase 1 habitat survey and Appendix 6-B contains the accompanying Target Notes, which provide further descriptions of features of interest.
The desk study revealed a number of species listed on Section 41 of the NERC Act and the Local BAP as being recorded in the 1km study area, including Thorow-wax ( Bupleurum rotundifolium ), Caraway ( Carum carvi ) and Stinking Goosefoot ( Chenopodium vulvaria ). However, these records are historical (the most recent, Thorow-wax, dating from 1966) and not in the immediate vicinity of the Site. In addition, the habitats that the Site supports are not considered suitable for these species. The most recent record of a Section 41 species was for Bastard Balm ( Melittis melissophyllum ), dated from 2001, and is considered likely to be a re- discovery of a population last recorded at Anthony House (approximately 1km to the east of the Site) in 1880. Again, it is considered unlikely that this species, which is associated with scrub habitats on calcareous soils, would be present on Site.
In general, the records of vascular and non-vascular plants provided by the record centre are considered unlikely to occur on the Site due to the modified nature of habitats present and the limited extent of semi-natural habitats.
Surrounding the fuel tanks were extensive areas of short mown amenity grassland supporting fine grasses such as Red Fescue ( Festuca rubra ) and occasional forb species including Creeping Buttercup ( Ranunculus repens ), Selfheal (Prunella vulgaris ) and the non-native Pirri- pirri-bur ( Acaena novae-zelandiae ).
On the slopes between the terraces and fringing the shoreline along the northern and southern boundaries of the Site were strips of broadleaved woodland, considered to be semi-natural in origin. The woodland supported a number of species indicative of this type of habitat, including Ash ( Fraxinus excelsior ), Hazel ( Corylus avellana ), Sweet Chestnut ( Castanea sativa ) and
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Sycamore ( Acer pseudoplatanus ). A band of woodland comprising Evergreen Oak ( Quercus ilex ), Ash, Hazel and Sycamore was situated north of the northern line of tanks. Ground flora species included Hart's-tongue ( Phyllitis scolopendrium ), Bramble ( Rubus fruticosus ) and Male- fern ( Dryopteris filix-mas ). There was also a line of mature Monterey Pines ( Pinus radiate ) between the woodland and the tanks.
Areas of Butterfly-bush ( Buddleja davidii ) and Bramble ( Rubus futicosus agg.) scrub were present, principally along the top of the concrete emergency fuel containment tanks. These areas of scrub were relatively low (1m high) and were clearly subject to regular periods of cutting and other management activities. In addition, there was a large area of Butterfly-bush scrub located west of the easternmost group of tanks, part of which had been cleared creating an area of bare ground.
Large, steep-sided, concrete tanks used for emergency containment of fuel were present, several of which contained standing open water up to 1m deep. These tanks supported virtually no aquatic or emergent vegetation, with the exception of a few isolated stands of Bulrush (Typha latifolia ) in one of the containment tanks. A large area of shallow water (5cm deep) was present at the time of the survey where a fuel tank had been removed. This supported no aquatic or emergent vegetation. In addition to the tanks above, there was also a small concrete water tank (4m x 4m) close to the main administrative buildings, containing water approximately 1m deep with a dense growth of Canadian Waterweed (Elodea Canadensis ).
The majority of the terrestrial habitats across the Site (amenity grassland, scrub, tall ruderal grassland) are considered to be of negligible conservation value. The small areas of semi- natural woodland are considered to be of importance at a Parish/Neighbourhood level. 6.4.5 Invasive plants
Canadian Waterweed is listed on Schedule 9 of the Wildlife and Countryside Act 1981 (as amended) and as such it is an offense to cause this plant to spread in the wild. Although the non-native Pirri-pirri-bur is not listed on Schedule 9 of the Wildlife and Countryside Act it was present across large areas of the Site and is clearly invasive in this location. Measures will be put in place to ensure that these invasive weeds are not spread during construction. 6.4.6 Terrestrial Invertebrates
The desk study revealed that a number of moth species considered to be of Principal Importance for biodiversity (listed on Section 41 of the NERC Act 2006) have been recorded in the locality. These include the garden tiger moth (Arctia caja ), the dusky thorn moth ( Ennomos fuscantaria ), mouse moth ( Amphipyra tragopoginis ) and knotgrass moth ( Acronicta rumicis ). The potential exists for several of these species to be found on the Site. However, given the limited diversity of habitats and species found on site and the localised nature of the semi- natural habitats, the Site is considered to be of negligible importance for invertebrates. 6.4.7 Amphibians
The desk study returned one record for common toad, listed on Section 41 of the NERC Act 2006, within the 1km study area. The standing open water present on site is considered to be sub-optimal habitat for amphibians due to the lack of marginal and aquatic vegetation and the steep sides of the tanks, which would make access by amphibians difficult. The Site is considered to be of negligible value to amphibian species.
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6.4.8 Reptiles
The mosaic of scrub, amenity grassland, woodland and steep concrete tanks are considered to offer suitable foraging habitat and basking opportunities for reptiles, in particular common lizard (listed on Section 41 of the NERC Act 2006). The desk study returned one historical record of common lizard, dating from 1985. It is considered unlikely that the Site supports a large population of common lizards, and therefore the Site is considered to be, at most, of Parish/Neighbourhood importance for reptiles. 6.4.9 Breeding birds
The mudflat and shoreline habitats within the Site are of limited value to nesting and breeding birds, since they are largely covered by water at high tide. The woodland and scrub areas are considered likely to support a range of breeding bird species characteristic of woodland habitat. Fifteen species of common woodland birds including blackbird ( Turdus merula ), robin ( Erithacus rubecula ), blue tit ( Cyanistes caeruleus ) and great tit ( Parus major ), were incidentally observed during the field survey, which provides an indication of the potential breeding bird assemblage. In addition, site staff provided anecdotal evidence that the broadleaved woodland fringing the shore supported a small heronry with 6-8 breeding pairs. The broadleaved woodland will not be affected by the proposed Development. Due to the regular cutting of the amenity grassland it is considered that ground nesting birds are unlikely to be present. The desk study returned hundreds of bird records, however; very few were of relevance to the terrestrial habitats the Site supports. The Site is considered to be of, at most, Parish/Neighbourhood importance for breeding birds. 6.4.10 Otters
Otters are listed as being present within the Plymouth Sound and Estuaries SAC but not in significant numbers. The desk study returned no records of otters within the 1km search area. It is considered likely that otters commute up and down the estuary in the vicinity of the proposed Development, however; given the large home range of otters (up to 20km) and the fact that the Site itself is considered to provide sub-optimal habitat to support otter holts, the Site is considered to be of Parish/Neighbourhood importance for otters. Nevertheless, otters are legally protected and therefore mitigation measures will be provided. 6.4.11 Bats
The desk study revealed several records of lesser horseshoe ( Rhinolophus hipposideros ) and greater horseshoe bat ( Rhinolophus ferrumequinum ), the most recent dating from 2005, approximately 1km from the Site. The larger, more mature trees within the strips of woodland, in particular the line of Monterey Pines may support bark crevices and cracks suitable for roosting bats. However, no obvious features were noted. All the buildings present on Site were well maintained and appeared to offer few opportunities for roosting bats to access the structures. An occasional open window was noted, however; the interior of the building appeared well lit with no obvious roof void. A tunnel was identified close to the northern boundary of the Site that could potentially be accessed by roosting bats. However, this tunnel is some distance from the proposed Development and therefore should bats use this feature it is considered unlikely that they would be affected by the works.
The mosaic of grassland, scrub and woodland habitats was considered to offer foraging opportunities for bat species. The Site is considered to be, at most, of Parish/Neighbourhood importance for bats.
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6.4.12 Dormice
The woodland areas on site support Hazel shrubs and Traveller's-joy ( Clematis vitalba ), both species utilised by foraging dormice. In addition, there was good connectivity between the canopy and shrub layers and therefore it may be considered potentially suitable to support dormice. However, the desk study returned no records of dormice and a review of aerial photographs indicates that the Site is relatively isolated and poorly connected to other areas of woodland and hedgerows in the wider landscape. It is also considered that the extent of woodland habitat available on site is not sufficient to support a viable population of dormice. It is, therefore, considered unlikely that dormice are present on site and they will not be considered further in the assessment. 6.4.13 Badgers
No evidence to suggest that badgers were present on the Site was identified. The Site security fence is dug into the ground which would also make access by badgers more difficult. For these reasons it is considered that badgers are not present within the Site boundary and they will not be considered further in the assessment. 6.4.14 Marine Habitats
The desk study revealed areas of intertidal mudflats and seagrass beds within the study area which are habitats of Principal Importance listed on Section 41 of the NERC Act 2006 and Cornwall BAP Priority habitats.
Video examination and species identification from grab samples identified a number of marine habitats (biotopes) as detailed in Figure 6.5 and Figure 6.6 and listed in Table 6-5. The results of the marine survey are presented in Appendix 6-C together with the value of ecological receptors and the justification for this valuation.
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Figure 6-5 Results of inter-tidal survey
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Figure 6-6 Results of subtidal survey (Note that this figure has been included to illustrate the results of the subtidal survey only, and the proposed jetty and dredging locations shown have since been revised)
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Table 6-5 Results of Marine and Intertidal Surveys
Biotope Name and Biotope/Species Ecological Receptor Corresponding Ecological Value Ecological Value and Scoping Decision Code Description Designations Sub-littoral mud in Shallow sublittoral muds, Benthic SAC habitat District/Borough The historical dredging regime and high use varying salinities extending from the extreme Subtidal Mud (variable Section 41 NERC Act of the estuary heavily impacts the sublittoral (estuaries) lower shore into the subtidal salinity) 2006 sediments leaving the Site impoverished and in variable salinity no significant numbers of important species (estuarine) conditions were identified. Nevertheless, the impacts SS.SMu.SMuVS on the subtidal mud will be considered in the context of the Internationally important SAC. Sub-littoral mixed Shallow sublittoral mixed Benthic SAC habitat District/Borough As for SS.SMu.SMuVS sediment in varying sediments in estuarine Subtidal Mud (variable Section 41 NERC Act salinity (estuaries) conditions, often with salinity) 2006 surface shells or stones,
enabling the development of SS.SMx.SMxVS diverse epifaunal communities as well as infaunal communities. Crepidula fornicata and Variable salinity mixed Benthic SAC habitat District/Borough As for SS.SMu.SMuVS Mediomastus fragilis in sediment characterised by Subtidal Mixed Section 41 NERC Act variable salinity the slipper limpet ( Crepidula Sediment 2006 infrallittoral mixed fornicata) and the (variable salinity) sediment polychaetes ( Mediomastus fragilis) and ( Aphelochaeta marioni). SS.SMx.SMxVS.CreMed
Yellow and grey lichens Vertical to gently sloping Splash Zone Estuarine Section 41 NERC Act Parish/Neighbourhood The small area of rocky habitat that on supralittoral rock bedrock and stable boulders Rocky habitat 2006 supported this biotope was deemed to be of in the supralittoral (or splash LBAP Priority Habitat only Parish/Neighbourhood importance zone) of the majority of due to its limited extent and its composition
LR.FLR.Lic.YG rocky shores are typically comprising common lichen species. In characterised by a diverse addition, it is considered highly unlikely that community of yellow and both terrestrial and marine construction grey lichens such as works will affect this biotope. Xanthoria parietina, Caloplaca marina, Lecanora atra and Ramalina spp.. Verrucaria maura on Upper littoral fringe bedrock, Splash Zone Estuarine Section 41 NERC Act Parish/Neighbourhood As for LR.FLR.Lic.YG
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Biotope Name and Biotope/Species Ecological Receptor Corresponding Ecological Value Ecological Value and Scoping Decision Code Description Designations very exposed to very boulders and stable cobbles rocky habitat 2006 sheltered upper littoral on very exposed to very LBAP Priority Habitat fringe rock sheltered shores which have a blanket covering of the black lichen Verrucaria LR.FLR.Lic.Ver.Ver maura. This zone is normally found below the yellow/grey lichen zone and there is not always a clear transition between the two. Pelvetia canaliculata on Lower littoral fringe bedrock Intertidal Section 41 NERC Act Parish/Neighbourhood As for LR.FLR.Lic.YG sheltered, variable or stable boulders and Estuarine rocky habitat 2006 salinity littoral fringe rock mixed substrata on very LBAP Priority Habitat sheltered to extremely
sheltered variable salinity LR.LLR.FVS.PeIVS shores characterised by a dense cover of the wrack Pelvetia canliculata, which often overgrows a crust of black lichens Verrucaria maura. Fucus spiralis on Sheltered to extremely Intertidal Section 41 NERC Act Parish/Neighbourhood As for LR.FLR.Lic.YG sheltered variable sheltered upper eulittoral Estuarine rocky habitat 2006 salinity upper eulittoral bedrock or mixed substrata LBAP Priority Habitat rock (boulders, large cobbles or
shells on mud) in variable salinity conditions LR.LLR.FVS.FspiVS characterised by a band of the spiral wrack Fucus spiralis. Ascophyllum nodosum Very sheltered to extremely Intertidal Section 41 NERC Act Parish/Neighbourhood This habitat within the intertidal region was and Fucus vesiculus on sheltered mid eulittoral Estuarine rocky habitat 2006 impoverished but connected to similar variable salinity mid bedrock, boulders or LBAP Priority Habitat habitat along the shoreline and so was given eulittoral rock cobbles subject to variable a value of Parish/Neighbourhood
salinity characterised by an importance. This receptor is therefore not impoverished community considered valuable enough for any LR.LLR.FVS.AScVS dominated by the wracks significant impacts to arise. Ascophyllum nodosum and Fucus vesiculosus .
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Biotope Name and Biotope/Species Ecological Receptor Corresponding Ecological Value Ecological Value and Scoping Decision Code Description Designations Ephemeral green and Eulittoral mixed substrata Intertidal Section 41 NERC Act Parish/Neighbourhood This habitat within the intertidal region was red seaweeds on (pebbles and cobbles Mixed Sediment 2006 given a value of Parish/Neighbourhood variable salinity and/or overlying sand or mud) that Sheltered Muddy importance as it provides some diversity disturbed eulittoral mixed are subject to variations in Gravels. among a fucoid dominated area. An substrata salinity and/or siltation, extremely small area of this biotope will be characterised by dense directly under the footprint of the blankets of ephemeral development (<40m 2) but the receptor is not LR.FLR.Eph.EphX green and red seaweeds. considered valuable enough for any The main species present significant impacts to arise. are Enteromorpha intestinalis , Ulva lactuca and Porphra spp.. Seagrass beds on littoral Mid and upper shore wave- Intertidal seagrass As Seagrass Beds: County Seagrass Beds are listed as a habitat of sediments sheltered muddy fine sand beds OSPAR List of principal importance on Section 41 of the or sandy mud with narrow- (mudflats) Threatened and/or NERC Act and the Cornwall BAP and has leafed eel grass Zostera also been listed by OSPAR. The seagrass LS.LMp.LSgr Declining Species and noltii at an abundance of Habitats beds adjacent to the shore, within the site, frequent or above. are designated as an AGSV. At the Section 41 NERC Act proposed Development site the seagrass Cornwall BAP Priority was found to be locally abundant, but was Habitat not a swathe of plants. However, the seagrass at the Site was linked to further As Mudflats: seagrass habitat either side of Yonderberry Point that appeared to be of good quality. SAC/Habitats Directive
Annex I Habitat Intertidal mudflats are listed as a habitat of Section 41 NERC Act principal importance on Section 41 of the Cornwall BAP Priority NERC Act and the Cornwall BAP. The Habitat mudflats adjacent to the shore, within the site, are designated as an AGSV. Whilst this habitat is outside of the SAC boundary, ‘mudflats and sandflats not covered by seawater at low tide’ is a qualifying feature of the adjacent Plymouth Sound and Estuaries SAC. Although the mudflat does not show exceptional diversity, probably due to the nature of the land use surrounding the Site, it is functionally linked to the SAC habitats and maintains connectivity between the mudflats across the wider area.
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Biotope Name and Biotope/Species Ecological Receptor Corresponding Ecological Value Ecological Value and Scoping Decision Code Description Designations
Given the abundance of seagrass and the low diversity of the mudflats, this biotope is given a value of County importance. The biotope will be under the footprint of the development in addition to possibly being affected by sediment deposition. Sternaspis scutata This species is a stout Sternaspis scutata Parish/Neibourhood This individual was found in grab sample burrowing polychaete worm, inhabits sandy and number 3 near the position of the new jetty. whitish-grey in colour, with a muddy substrata, Although it has no designation, it is a rare leathery texture. where it burrows head- species only recorded along the south down, exposing the Devon coast, from Plymouth Sound to gills on its posterior Otterton Point, and in Dorset at Portland end. Harbour. As only one individual was found, it is not considered valuable enough for any significant impacts to arise. The effects on its habitat will be assessed in the context of the SAC. Native oyster Native oyster is a bivalve Ostrea edulis is OSPAR List of Negligible Only one live oyster was found in grab mollusc that has an oval or associated with highly Threatened and/or sample number 6. Oysters are usually pear-shaped shell with a productive estuarine Declining Species and clustered in groups associated with highly rough, scaly surface. The and shallow coastal Habitats productive estuarine and shallow coastal two halves (valves) of the water habitats on firm Section 41 NERC Act water habitats. They can be found on firm shell are different shapes. bottoms of mud, rocks, 2006 mud, rock, muddy sand, muddy gravel with muddy sand, muddy shells and hard silt. One of the most suitable gravel with shells and Cornwall BAP priority settlement substrates is natural oyster shell. species hard silt. Hence they are usually found with other oysters. It is likely that this individual detached from the oyster beds upstream and is unlikely to form part of a significant group, thus it will not be considered further in the impact assessment. Thornback Ray A short-snouted ray with Thornback ray OSPAR List of Parish/Neighbourhood Only one individual was seen on video typical diamond shape and frequents a wide Threatened and/or transect number 4. As only one individual sharply angled pectoral fins variety of grounds Declining Species was found, it is not considered valuable approaching 90 degrees. from mud, sand, enough for any significant impacts to arise. The colour is variable, shingle and gravel. It This is a highly mobile species and therefore usually a mottled, blotchy is less frequently impacts are considered unlikely. brown to grey, with recorded on coarser numerous small dark spots sediment types. They
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Biotope Name and Biotope/Species Ecological Receptor Corresponding Ecological Value Ecological Value and Scoping Decision Code Description Designations and yellowish patches. are also found on Dorsally the body is covered patches of sediment with coarse prickles, which among rocky outcrops are present from hatching. and boulders. It may In addition, large, backward be found to a depth of pointing thorns (called 300m but most bucklers) are scattered over common between 10 – the dorsal surface, each of 60m. Although mainly which has a thick button-like a non-migratory base. species, the fish often moves close inshore during the spring.
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6.4.15 Migratory Fish
Migratory fish including Atlantic salmon, allis shad, twaite shad, sea trout, European smelt and European eel are known to pass through the estuary (see Table 6-6 below, from information provided by the EA). Atlantic salmon are a qualifying feature of Dartmoor SAC, and allis shad are a qualifying feature of the Plymouth Sound and Estuaries SAC. The presence of European smelt and European eel are a reason the Tamar Estuary MCZ is designated, and European eel are classified as ‘critically endangered’ on the IUCN Red Data List (Ref 6-9). All of these fish species are listed on Section 41 of the NERC Act 2006 as species of Principal Importance.
Table 6-6 Migratory fish species present in the Tamar Estuary
Species Designation Migratory Period Allis shad Qualifying feature of April – July (peak May/June) Plymouth Sound and Estuaries SAC. Atlantic salmon Qualifying feature of April – December (peak Dartmoor SAC. June/July/August/September/October) Sea trout Section 41 of the NERC March – December (peak May/June/July) Act 2006 species of Principal Importance Salmon & Sea Section 41 of the NERC April – June trout smolts Act 2006 species of Principal Importance Sea trout kelts Section 41 of the NERC November – December (downstream migration) Act 2006 species of Principal Importance European Reason for designation of February – April smelt Tamar Estuary MCZ Eels (juvenile) ‘Critically endangered’ on March – May (Sea to freshwater) the IUCN Red Data List Eels (adult) ‘Critically endangered’ on Autumn months (downstream migration) the IUCN Red Data List River and sea Listed as being present in April - July lamprey the Plymouth Sound and Estuaries SAC but not at significant population levels Twaite shad Listed as being present in April – July (peak May/June) the Plymouth Sound and Estuaries SAC but not at significant population levels
The only known spawning site for allis shad within the UK is located in the upper Tamar estuary and the lowest freshwater areas of the Tamar, with the main spawning site considered to be
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below Gunnislake Weir (Appendix 6-F). Allis shad enter the Tamar mostly within the May to June period.
During May Atlantic salmon and sea trout smolt are moving down the estuary to the open sea. At the same time, adult Atlantic salmon and sea trout are beginning to move up the estuary to freshwater spawning sites.
The main spawning site for European smelt in the Tamar is considered to be below Gunnislake Weir. Smelt accumulate in the lower estuary from October onwards before ascending to spawn between February and April.
Table 6-6 illustrates the importance of the Tamar Estuary for a wide range of migratory fish species, particularly between the months of April to August. The study area is therefore considered to be of International importance for migratory fish. 6.4.16 Other Fish Species
The Plymouth Sound and Estuaries Complex SAC is part of a year-round designated nursery area for bass. The desk study revealed that the proposed Development is also located within broader scale spawning areas for lemon sole, sole and sprat; and nursery areas for monkfish, lemon sole, mackerel, spurdog and Whiting.
Of these, mackerel, whiting, monkfish and sole are all listed on Section 41 of the NERC Act 2006 as species of Principal Importance.
The study area is therefore considered to be of Regional importance for other fish species. 6.4.17 Shellfish
The Site lies within 3km of the Designated Shellfish Waters of the Lynher_E and the Classified Bivalve Mollusc Harvesting Area in the Tamar. The bivalves specifically mentioned include the Hard-shell clam, mussels, common cockle, razor shells and the great scallop. Commercial fishing of bivalves in these grounds is currently prohibited.
None of the above species were found in significant numbers during the subtidal surveys. The grounds are considered to be far enough away from the Site that any potential impacts from the release of sediment as a result of the works will no longer be significant due to the naturally silty nature of the estuary and the large dilution factor. The impacts on shellfish will therefore not be considered further in this assessment. 6.4.18 Marine Mammals
The desk study revealed two records of stranded common dolphin dating from 2005 and 2007; two records dating from 2007 of a group of four Risso’s dolphin in St John’s Lake; two records (both from 2004) of harbour porpoise and two records of bottlenose dolphin, both from 1999 between Seaton and Murraytown. In addition, four records of grey seal were returned from between 1966 and 2006. The results of the recent Cornwall Wildlife Trust Seaquest Netsafe project, which aimed to gather information on the distribution of cetaceans around the Cornwall coast, recorded only one common dolphin in three years, off Portwrinkle, at least 15km away around the coast (Ref 6-10).
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All the above species are afforded protection under the Conservation of Habitats and Species Regulations 2010 (as amended), the Wildlife and Countryside Act 1981 (as amended), the Bern and Bonn Convention. With the exception of grey seal, all are also listed on Section 41 of the NERC Act (2006)
Although sightings are infrequent, the study area is considered to be of District/Borough importance for marine mammals. 6.5 Selection of Ecological Receptors
Table 6-7 Selection of Key Ecological Receptors
Ecological Receptor Associated Nature Potentially significant species/habitats Conservation effect Value Key Ecological Receptors
Subtidal mudflats Varied infaunal International. Direct loss of SAC habitat associated with communities, However, the subtidal (subtidal mud and mixed Plymouth Sound and particularly bivalves and mud and mixed sediments) during Estuaries SAC other invertebrates. sediments surveyed construction (piling and during the marine dredging) and through survey were capital and maintenance impoverished and no dredging. significant numbers of Piling, capital dredging important species and maintenance dredging were identified. The operations causing an habitats within the increase in suspended SAC surveyed during sediment and sediment the marine survey deposition leading to were considered to smothering of habitats. be of District/Borough
value.
Bird species associated The bird species for International for Disturbance to wintering with the Tamar which the Tamar SPA qualifying bird species throughout Estuaries Complex SPA Estuaries Complex species construction works (in Bird species associated has been designated particular piling works). an SPA are included with the Lynher Estuary National importance Capital and maintenance within this receptor SSSI, St John’s Lake for SSSI habitats and dredging operations have (little egret). In SSSI wintering wader and the potential to indirectly addition there are a wildfowl species affect intertidal habitats number of other e.g. by an increase in
wader and wildfowl suspended sediment and species mentioned sediment deposition within the SSSI causing smothering of citations. These have habitats and a loss of also been included feeding resource. within this receptor.
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Ecological Receptor Associated Nature Potentially significant species/habitats Conservation effect Value Intertidal mudflats and subtidal sediments.
Habitats and associated Intertidal sand and National Deposition of dredged species within Whitsand coarse sediments, material at Rame Head and Looe Bay MCZ subtidal sand and disposal site has the coarse sediments, rocky potential to cause an habitats, seagrass beds. increase in suspended Ocean quahog, pink sediment and sediment sea-fan, sea-fan deposition leading to anemone, stalked smothering of habitats. jellyfish.
Seagrass beds Wintering and on- County Direct loss of habitat under passage birds, intertidal piling. mudflats Shading of habitat beneath new jetty. Capital and maintenance dredging operations have the potential to affect seagrass beds by an increase in suspended sediment and sediment deposition causing smothering of habitats.
Migratory fish: Subtidal habitats International Disturbance/risk of Atlantic salmon, mortality of migratory fish qualifying feature of during construction (piling Dartmoor SAC and dredging operations) and operation Allis shad, qualifying (maintenance dredging). feature of Plymouth Sound and Estuaries SAC European smelt, reason for designation of Tamar Estuary MCZ Sea trout, Section 41 of the NERC Act 2006 European eel, reason for designation of Tamar Estuary MCZ, ‘critically endangered’ on the IUCN Red Data List Twaite shad, river
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Ecological Receptor Associated Nature Potentially significant species/habitats Conservation effect Value lamprey and sea lamprey, present in Plymouth Sound and Estuaries SAC but not at significant population levels
Other fish species: Subtidal habitats Regional Disturbance/risk of bass, lemon sole, sole, mortality of fish during sprat, monkfish, construction (piling and mackerel, spurdog, dredging operations) and whiting operation (maintenance dredging).
Marine mammals, Subtidal habitats District/Borough Disturbance due to piling including bottlenose and dredging works dolphin, harbour (construction phase) and porpoise and grey seal, from maintenance which are present within dredging. the Plymouth Sound and Estuaries SAC but not at qualifying population levels.
Ecological Receptor Associated Nature Effect requiring species/habitats Conservation mitigation Value Other ecological receptors requiring mitigation on the basis of legislation
Otter Intertidal mudflats Parish/ Disturbance to any Neighbourhood commuting otters during construction.
Breeding birds Trees, scrub and Parish/ Damage or destruction of woodland Neighbourhood a nest while it is in use or being built.
Invasive plant species Canadian waterweed Negligible Potential to spread plant during construction.
Ecological Receptor Associated Nature Reason receptor species/habitats Conservation scoped out Value Ecological receptors not considered further
Habitats associated with Sandbanks covered by International No direct or indirect effects
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Plymouth Sound and sea water, estuaries, predicted on these Estuaries SAC shallow inlets and bays, habitats. including habitats reefs, Atlantic salt associated with Lynher meadows, mudflats and Estuary SSSI, and St sandflats not covered by John’s Lake SSSI seawater at low tide.
Tamar Estuaries Avocet International No direct or indirect effects Complex SPA predicted on avocet.
Dartmoor SAC (Atlantic Northern Atlantic wet International No direct or indirect effects salmon considered heaths with Cross- predicted on these under migratory fish, leaved heath, European habitats and species. otters considered on Dry heaths, blanket basis of legal protection) bogs and sessile oak woods. Southern damselfly
Tamar-Tavy SSSI Wintering and on- National No direct or indirect effects passage birds, intertidal predicted. mudflats
Plymouth Sound Shores Geological interest National No direct or indirect effects and Cliffs SSSI predicted.
Mount Wise SSSI Geological interest National No direct or indirect effects predicted.
Western King SSSI Geological interest National No direct or indirect effects predicted.
Richmond Walk SSSI Geological interest National No direct or indirect effects predicted.
Kingsand to Sandway Geological interest National No direct or indirect effects Point SSSI predicted.
Tamar Estuary MCZ Intertidal biogenic reefs, National No direct or indirect effects European smelt and intertidal coarse predicted. European eel part of the sediment, native oyster migratory fish receptor and blue mussel
Woodland Wood Valley Woodland, hedgerows, District/Borough No direct or indirect effects LNR meadow, stream predicted.
Budshead Wood LNR Woodland, tidal creek District/Borough No direct or indirect effects predicted.
Tincombe Reserve Woodland County No direct or indirect effects CWS predicted.
Lower Lynher Estuary Saltmarsh habitat County No direct or indirect effects CWS predicted.
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St John’s Lake CWS Saltmarsh habitat County No direct or indirect effects predicted.
Clarrick and Pigshill Woodland County No direct or indirect effects Woods CWS predicted.
Churchdown Farm Meadows Parish/ No direct or indirect effects Community Nature Neighbourhood predicted. Reserve
Terrestrial plants and Broadleaved woodland, Parish/Neighbourhoo Receptor not sufficiently habitats Scrub, amenity d for broadleaved valuable for impacts to grassland, ruderal woodland, negligible arise. The area of scrub grassland, common for remaining habitats and ruderal grassland species of reptile, habitat to be directly amphibians and affected by the proposed invertebrates Development is negligible.
Terrestrial invertebrates Scrub, woodland, Negligible Receptor not sufficiently amenity grassland valuable for impacts to arise. The area of terrestrial habitat to be directly affected by the proposed Development is negligible.
Amphibians Standing water in the Negligible Receptor not sufficiently storage tanks, scrub, valuable for impacts to woodland, amenity arise. grassland
Reptiles Scrub, woodland, Parish/ Receptor not sufficiently concrete tanks and Neighbourhood valuable for impacts to areas of bare ground arise. The site compounds will be situated on areas of hardstanding and amenity grassland, with only a small amount of scrub clearance required.
Bats Woodland, scrub, Parish/ Receptor not sufficiently amenity grassland, Neighbourhood valuable for impacts to ruderal grassland arise. The area of terrestrial habitat to be directly affected by the proposed Development is negligible.
Dormice Woodland, scrub Negligible No direct or indirect effects predicted as considered to be absent from the Site.
Badgers Woodland, scrub, Negligible No direct or indirect effects amenity grassland predicted as considered to be absent from the Site.
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Intertidal mixed Parish/ Receptor not sufficiently sediment Seaweed Neighbourhood valuable for impacts to arise. The area of intertidal mixed sediment to be directly affected by the proposed Development is negligible.
Intertidal estuarine rocky Intertidal Seagrass Parish/ Receptor not considered habitat beds, intertidal mixed Neighbourhood valuable enough for sediment significant impacts to arise.
Splash zone estuarine Intertidal mudflats Parish/ Receptor not considered rocky habitat Neighbourhood valuable enough for significant impacts to arise. No direct or indirect impacts predicted.
Shellfish including Subtidal habitats Negligible Only one individual native native oyster oyster was recorded on Site, the habitat on Site is unsuitable to support large numbers of shellfish. Receptor not sufficiently valuable for impacts to arise.
Thornback ray Subtidal habitats Parish/ Only one individual of this Neighbourhood highly mobile species was recorded. Receptor not sufficiently valuable for impacts to arise.
Sternaspis scutata Subtidal habitats Parish/ Only one individual of this Neighbourhood rare species was recorded. Receptor not sufficiently valuable for impacts to arise.
6.6 Design and Mitigation
A number of ‘Key Ecological Receptors’ have been identified. This section identifies the likely impacts upon these Key Ecological Receptors and details the mitigation measures proposed.
Mitigation for impacts on ‘other ecological receptors’ are also included in order to comply with current wildlife legislation and take into account policy drivers and best practice guidelines.
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6.6.1 Construction
Subtidal mudflats associated with Plymouth Sound and Estuaries SAC
Loss of habitat
The construction of a new jetty, dolphin moorings and the extension of the dredge pocket will result in the permanent loss of subtidal estuarine habitats.
The footprint of the works has been limited as far as possible, with the proposed berth pocket the same size (1.35ha) as the existing berth pocket. There is an overlap of 0.92ha between the existing and the new, resulting in 0.43ha of currently un-dredged habitat to be removed. An additional 0.3ha would also be lost during the capital dredge where the proposed berth pocket sides would slope. In relation to the proposed berth pocket, this results in a total of 0.73ha of currently un-dredged habitat to be removed, and a total dredge area of 1.65ha (= 0.92ha + 0.43ha + 0.3ha) .
Some dredging will also need to be carried out to enable access to the western side of the jetty over an area of 1.36ha (the Northern Approach channel).
The overall permanent loss of habitat as a result of dredging will be 3.01ha (= 1.35ha + 0.3ha + 1.36ha)).
The detailed design for the Development has not yet been undertaken, but it is anticipated that the area beneath the piles associated with the new jetty, dolphin moorings and pontoon will be approximately 0.018ha, which represents a worst case scenario.
Current construction methodology includes proposals to side-cast arisings from pilings adjacent to the new subtidal piles only (to reduce impacts on intertidal habitats, particularly seagrass beds, where the piles fall outside of the contaminated area at the proposed jetty head. The approximate volume of arisings to be side-cast is 250m 3.
Habitat diversity may be limited through increased shading as a result of the presence of the jetty (particularly in shallower waters). However, the removal of the existing jetty structure should ensure the restoration of SAC habitats beneath. The existing jetty covers an area of approximately 0.2ha and the new jetty will cover an area of 0.32ha, so only an additional 0.12ha (=0.32-0.2) would be shaded when compared to the current situation. Whilst shading may reduce habitat diversity, it is not considered to result in permanent habitat loss.
Physical damage to habitats as a result of increased siltation and release of contaminants from contaminated sediment
Construction activities, in particular piling and dredging, have the potential to temporarily add significant sediment loads to the estuary. The proposed Development requires the dredging of sediment up to a depth of 2.5m below bed level from the area in front of the jetty head to enable access to the jetty. The estimated volume of sediment arisings from this capital dredging is approximately 37,000m 3 (19,000m 3 from the area in front of the northern mooring dolphins on the east side of the jetty and 18,000m 3 from the western side of the jetty).
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The drilling of the piles which will support the jetty will require the removal of sediment. The current estimated volume of arisings is approximately 3,450m3, of which 250m 3 will be side-cast immediately around the subtidal pile locations only. The remaining material is contaminated and will be collected and disposed of, or treated, on land.
Analysis carried out to date indicates that the sediment has some elevated concentrations of metals, PAH and PCB compounds above the lower action/effect levels but generally below upper action/effect levels. However, one of the sediment samples taken from the proposed jetty head showed levels of arsenic and PCB 25 that exceeded the upper limits. Sediment arisings from this location are not suitable for disposal at sea and will be collected and disposed of, or treated, on land. It will be the contractors responsibility to characterise all waste and ensure that it is reduced, reused or disposed of in a suitable manner. There is therefore potential for: • Dissolution of contaminants out of sediment/soil; • Suspension of contaminated or non-contaminated particulates, and; • Subsequent migration up or downstream of the Site due to wave, wind and tidal action. During the construction works measures will be taken to minimise disturbance of sediment and contain migration of sediment. These will include: • Taking additional precautionary measures while working in any locations identified as having elevated concentrations of contaminants. Elevated levels of contaminants were only identified at a single location.
• Minimise as far as possible the extent of work requiring contact with the river bed.
• Ensuring the contractor uses methods which minimise sediment disturbance, migration and arisings. This includes ensuring that the best practice and plant are used in the design and execution of the works. This may include standard measures such suction dredging plant, and flush containment and collection during piling.
The mitigation measures outlined above will limit disturbance and migration of sediment and subsequent sediment re-deposition.
Pollution from construction
During construction of the new jetty and demolition of the existing jetty, there is the potential for hazardous substances or waste materials to enter the watercourse. To limit the risk of pollution entering the estuarine environment, measures will be taken to ensure that contaminating substances are properly contained, during storage and use, both in the marine operations and the land operations. These include:
• PPG5 published by the EA, 2007, for Working In or Near a Watercourse will be followed as a minimum standard. This includes recommendations for fuel containment and the use of less hazardous types of machinery oil.
• All bulk storage of fuel, oils and other contaminating substances will include secondary containment. Emergency spill/leak containment kits will be available throughout the construction site where contaminative substances are being used or transported. An emergency spill response procedure will be put in place and conveyed to all site staff.
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• Best practice procedures will be used to contain potentially contaminating substances during the demolition of the existing jetty structures and construction of new jetty structures.
• Refuelling, repair and maintenance of land based construction plant will be carried out within a designated bunded area to avoid pollution from spillages and leaks.
• Measures will also be put in place to contain all demolition and construction wastes, to prevent waste falling onto the estuary bed or into the water column.
The following measures will be taken to minimise the potential for pollution during the demolition of the existing jetty:
• Empty and flush all fuel and sullage pipelines and any associated equipment. • Remove all equipment, buildings, tanks, pipework, etc. from the jetty head to barges for transport to a commercial wharf for disposal/re-cycling. • Remove all pipelines, cables, ducting and pipe supports from the approach jetty to barges for transport to a commercial wharf for disposal/re-cycling. • Demolish and dispose/re-cycle the redundant buildings and pipework on the land at the jetty root. • Demolish the existing jetty head, approach structure and mooring dolphins by cutting and breaking out the concrete deck and beam elements, using floating plant. • Piles to be cut off at or below existing seabed, using floating plant and ROVs or divers. This will minimise the amount of sediment disturbance during these activities. • Dispose of all materials by appropriate recycle or disposal method. • Measures will be put in place to contain all hazardous substances, demolition material and prevent waste materials falling onto the seabed or polluting the watercourse. There will be response procedures in place to ensure that any materials entering the watercourse are contained and recovered quickly to limit the impact caused. • Specific mitigation and waste management measures will be developed by the contractor carrying out the decommissioning work. The contractor will be required to comply with current UK guidance and best practice. During construction, best practice will be used to ensure that excess sediment/soil run off from the land construction site does not occur. Controlling measures will include:
• Carry out site investigation in the locations affected by the proposed Development, including chemical analysis of soil samples. Where significantly elevated concentrations (assessed based on current UK guidance and regulation) of determinands are identified additional remediation measures will be taken. Depending on the volume of soil impacted, this could include removal and off-site disposal of the impacted soils, or local containment.
• A Drainage Management Plan will be produced to ensure that surface water runoff from construction compounds is appropriately managed and treated prior to entering into any waterbody.
• Containment of soil stockpiles.
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• Hardstanding and roads will be cleaned frequently where soil is being deposited from vehicles.
• Cleaning of vehicles and equipment will be carried out in an area with drainage containment.
The above mitigation measures are contained within a CEMP which has already been prepared.
Assuming the mitigation measures described above, and in more detail in Chapter 5, are in place, it is considered that the potential for water quality effects on the Tamar Estuary associated with land based and marine based construction activities is restricted to the possibility of localised isolated sediment contamination, contained spills, and local sediment disturbance on a short term basis. The mitigation procedures in place will limit these to minor incidents and allow rapid remediation with no significant impact to the wider area.
Bird species associated with Tamar Estuaries Complex SPA, Lynher Estuary SSSI, St John’s Lake SSSI
Disturbance to SPA features by piling
Given the low numbers of little egret recorded in the count sector, the amount of available habitat nearby (in particular St John’s Lake, which provides foraging habitat for significant numbers of waders and wildfowl and is designated as both an SSSI and an SPA), no specific mitigation is proposed.
Disturbance to SSSI features by piling
St John’s Lake SSSI is approximately 1.4km to the south of the Site at its closest point beyond Torpoint. There is no direct line of sight between the two areas. Although no surveys were carried out during the winter, from BTO core count data for 2006/7-10/11, Tamar Estuaries (South) Sector 10 supported low numbers of wigeon (51) and no black-tailed godwit. These species are the SSSI interest features as defined by the condition assessment compiled in August 2013 (Ref 6-11). The number of wigeon recorded in the entire count sector is 1% of the number the SSSI was notified for.
The Lynher Estuary is located approximately 2km to the west of the Site beyond Wilcove. There is no direct line of site between the two areas. Of the bird features listed on the citation, including shelduck, oystercatcher, mallard and curlew, from BTO core count data for 2006/7- 10/11, the entire Tamar Estuaries (South) Sector 10 supported limited numbers of these species.
It is considered that the numbers of waders and wildfowl to be found in the habitats adjacent to the jetty are likely to be particularly low given the sub-optimal nature of the foraging habitat in this area and that the area is subject to a degree of disturbance (from boat traffic and when re- fuelling is in operation). Both SSSIs are of a sufficient distance from the Site that any birds using the SSSI habitats will not be disturbed by piling works. No specific mitigation is therefore proposed.
Disturbance from other construction activities
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The demolition of the existing jetty and land-based infrastructure is planned for between February 2018 and August 2018, just within the on-passage period and wintering period.
August to October is the peak on-passage period for little egret. By the time the on-passage little egret arrive the majority of the demolition will be completed. The mudflats around the jetty have already been assessed as not being a key foraging or roosting resource for little egret, therefore should any little egret be disturbed when using those habitats, it is considered that there is sufficient habitat nearby which the birds can move to. No specific mitigation is therefore proposed.
The numbers of over-wintering waders and wildfowl in the vicinity of the Site is likely to be low given the sub-optimal nature of the foraging habitat in this area and that the area is subject to a degree of disturbance (from boat traffic and when re-fuelling is in operation). Both SSSIs are of a sufficient distance from the Site that any birds using the SSSI habitats will not be disturbed by piling works. No specific mitigation is therefore proposed.
Loss and damage to foraging habitats as a result of increased siltation and pollution
The proposed Development requires the dredging of sediment up to a depth of 2.5m below bed level from the area in front of the jetty head. The estimated volume of sediment arisings from the capital dredging is approximately 37,000m 3.The drilling of the piles which will support the structure will require the removal of sediment. The current estimated volume of arisings is approximately 3,450m3, of which 250m 3 will be side-cast immediately around the subtidal pile locations only. The remaining sediment from the drilling of the piles is contaminated and will be collected and disposed of or treated on land.
The potential exists for increased sediment loads to be released from construction works affecting intertidal mudflats in the vicinity of the works. Dredging may also disturb sediment containing toxic materials such as TBT, heavy metals and hydrocarbons, causing the contaminated sediment to be re-deposited elsewhere or to leach into the water environment and affect water quality. Potential also exists for pollution during construction, for example from fuel/diesel spillages. It has already been demonstrated that the intertidal mudflats close to the existing jetty are not considered to be a key foraging resource for birds. However, although the intertidal mudflats in this location are not included within any designated site they are clearly functionally linked to nearby SPA and SSSI habitats.
During the construction works measures will be taken to minimise disturbance of the sediment, to contain the migration of sediment and to minimise the risk of a pollution incident (as detailed above for the Plymouth Sound and Estuaries SAC). In addition, side-casting will only be undertaken within the subtidal zone to limit the potential impacts on intertidal mudflats.
Whitsand and Looe Bay MCZ
Physical damage to habitats and species as a result of increased siltation
Disposal of approximately 37,000m 3 of sediment from the capital dredging has the potential for increased sediment loads to temporarily affect the habitats and species within the MCZ. As per
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the existing maintenance dredge licence (licence number L/2014/0063/1), the conditions of the licence for the capital dredge works are anticipated to state:
• No disposal is to take place at the disposal site from four hours before high water at Devonport until the time of high water at Devonport.
• The licence holder must ensure material is disposed of to the south-west corner of the Rame Head disposal site.
These measures will minimise the potential for movement of suspended sediment in a northerly direction, towards the MCZ.
Seagrass beds
Loss and damage of habitat by piling and dredging
Construction of the jetty will result in the permanent loss of seagrass beds on the intertidal zone through the installation of piles. The removal of the existing jetty structure should ensure the restoration of seagrass habitats in this now unshaded area. The existing jetty covers an area of 0.2ha and the new jetty will cover an area of 0.33ha, so only an additional 0.13ha (=0.33 - 0.2) would be beneath the new jetty structure when compared to the current situation. The restoration of seagrass beds elsewhere in the intertidal zone will be encouraged by removing crabbing tiles from the area within the DIOs control, which will increase the area of substrate available for colonisation. In addition, it is understood that intertidal bait digging and crabbing, currently causes disturbance to the seagrass beds. This activity will be discouraged through the installation of new signage.
Dredging operations have the potential to affect seagrass beds by an increase in suspended sediment and sediment deposition causing smothering of habitats. A small amount (250m 3) of uncontaminated sediment arising from piling operations will be side-cast immediately around the subtidal pile locations only, as far as possible from the intertidal zone to reduce the risk of sediment re-deposition on the intertidal area. Mitigation proposals outlined for the Plymouth Sound and Estuaries SAC aim to minimise sediment deposition and dispersal during dredging and are applicable to this key ecological receptor.
In addition, the risk of a pollution incident, particularly oil/fuel spillages during construction could damage seagrass beds. The measures outlined for the Plymouth Sound and Estuaries SAC to reduce the risk of a pollution incident occurring are considered suitable mitigation for this key ecological receptor.
Migratory fish (Atlantic salmon, allis shad, European smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey)
Disturbance/mortality to migratory fish
Piling works associated with the construction of the new jetty head and the new mooring dolphins could act as an acoustic barrier to fish migration if carried out during the core migratory period. In addition, impact sound from any piling undertaken during the migratory period could adversely affect the health of fish or adult eels if they are exposed to it for a sufficiently long time and intensity. In addition, underwater noise and light from the demolition of the existing jetty could disturb migratory fish.
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The core sensitive period for migratory fish, particularly allis shad and Atlantic salmon, but also sea trout, European eel and sea lamprey, is between 1 st April and 31 st August. The greatest level of underwater noise generated by the proposed Development are likely to be during percussive piling.
Subacoustech Environmental Ltd undertook an assessment of the potential impact of underwater noise from activities associated with the proposed Development, with respect to locally sensitive fish species. The assessment considered three main noise sources: percussive piling, pile case oscillation and augering/drilling (Ref 6-12). It has not been possible to agree an appropriate noise threshold for percussive piling given the uncertainty in the current evidence base. As such, percussive piling will not be carried out during the core sensitive period of 1 st April until 31 st August.
Vibro-piling, pile case oscillation and auguring/drilling typically generate significantly lower noise levels in comparison with percussive piling, and NE and Cefas are in agreement that these construction methods can be carried out at any time of year. However, in order to validate the Subacoustech predictions and to provide additional reassurance regarding the noise levels associated with these activities at this specific site, in-situ monitoring of the noise levels generated by each of the different vibro-piling, pile case oscillation and auguring/drilling activities at the beginning of the work, and outside the core sensitive period of 1 st April to 31 st August, will be undertaken. This will involve monitoring the noise levels produced by these activities for the first four piling events and comparing these to the predicted levels, before carrying out these activities during the 1 st April to 31 st August period.
Demolition of the existing jetty is currently programmed for February to August 2018. This includes the removal of the existing piles. Piles will be cut off 300mm below seabed level to prevent leaving an obstruction on the seabed. Sediment surrounding the pile will first be moved to allow access to the pile. Concrete piles will be ‘snipped’ at the base using hydraulic shear cutters. For steel piles mechanical cutting or water jet cutting may be used.
The timing of these works are within the sensitive period for migratory fish. However, the noise and vibrations from pile removal is expected to be lower than that experienced when installing piles, and all equipment will operate from floating plant during daylight hours, reducing potential impacts on migratory fish. Significant adverse impacts are therefore not anticipated.
Measures will be put in place to contain all demolition material and prevent waste materials falling into the estuary.
Loss and damage to foraging habitats as a result of increased siltation and pollution
The piling and dredging works are planned to take place outside of the fish migratory period. As outlined earlier, mitigation measures are to be put in place to minimise sediment remobilisation and movement and to reduce the risk of any pollution incident. The effects of any sediment movement are likely to be localised both spatially and temporally, therefore by the time fish migration is underway, localised effects will no longer be significant.
During the removal of piles, localised sediment disturbance is expected as it needs to be removed to allow access to the pile. Some sediment may also be disturbed through the pile removal process. However, this is expected to be extremely localised and of such a short duration that no specific mitigation is proposed.
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Other fish species (bass, lemon sole, sole, sprat, monkfish, mackerel, spurdog, whiting)
Disturbance/mortality to resident fish species
It is considered that the high levels of noise and vibration that already exist in the Estuary mean that the limited period of percussive piling from September to March will not cause any significant long term effects on resident fish species. From the results of the marine surveys it is also considered that the subtidal habitats in the vicinity of the jetty provide sub-optimal foraging habitat to species such as bass (due to the history of dredging) and that there is sufficient alternative foraging habitat in the estuary that it is unlikely large shoals of young bass are found around the jetty. In addition, fish are mobile species that can move quickly away from any significant disturbance. Fish fry do not possess swim bladders and will be relatively resistant to noise effects arising from the piling operation. No effects on this fish life stage are therefore predicted and therefore no specific mitigation is proposed.
Loss and damage to spawning habitat for resident species
The timing of percussive piling and dredging throughout the winter means that any adverse effects through sediment dispersal will no longer be significant by the time of the main spawning season for lemon sole (April-September), sole (March to May, peaking in April) and sprat (May to August) (Ref 6-13).
The mitigation measures outlined above for the Plymouth Sound and Estuaries SAC to minimise sediment disturbance and re-deposition and reduce the likelihood of a pollution event are also considered relevant for this key ecological receptor.
Loss and damage to foraging habitats as a result of increased siltation and pollution
The mitigation measures outlined above for the Plymouth Sound and Estuaries SAC to minimise sediment disturbance and re-deposition and to reduce the risk of pollution entering the estuary are considered applicable to this key ecological receptor.
Marine mammals (bottlenose dolphin, harbour porpoise and grey seal)
Disturbance from piling and dredging
No mitigation is proposed given that marine mammals occur so infrequently in the Tamar.
Other ecological receptors requiring mitigation
Otter
Otter are known to commute through the estuary and the construction works have the potential to disturb any otters moving past the works. However, construction will be limited to a 12 hour day, with ten hours of activity and no evening/night time working. Access to the foreshore for otters will be maintained at all times. Any construction lighting will be directional, focussing only on the area of work, to maintain dark areas of water that the otter can utilise. It is anticipated
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that disturbance to otters will be minimal due to the low numbers considered likely to use the Site.
Breeding birds
It is proposed that a site compound and working area will be established within the Thanckes OFD. This will involve clearance of small amounts of scrub. Access to the site compound and working area will be on existing surfaced access tracks (see Figures 2-2 and 2-3 in Chapter 2 of the ES). The habitat of most value to breeding birds on Site, broadleaved woodland, is to be unaffected. To limit any impacts on breeding birds which may be using the scrub, vegetation clearance will be completed outside of the bird breeding season (end of February to end of August). If this is unavoidable, clearance will be carried out under close supervision by an experienced ecologist. In the event that an active nest is identified, it will be left undisturbed with a suitable buffer until the young have fledged.
Invasive plant species
Measures will be put in place as part of the CEMP to ensure that Canadian Waterweed and Pirri-pirri-bur are not spread during construction. 6.6.2 Operation
Subtidal mudflats associated with Plymouth Sound and Estuaries SAC
Physical damage to habitats as a result of increased siltation
The existing berth pocket is dredged as and when necessary to maintain the minimum depth. It has been dredged along with other areas under a general 3 year Food and Environment Protection Act (FEPA) licence which allows for the removal of up to 367,000 tonnes over a three year period. The berth was last dredged in 2005 and 4,036m 3 was recorded as being removed. This gives an average silt accumulation of 300mm depth over 7 years. The proposed berth pocket is the same dimension as the existing berth pocket, it is therefore expected that a similar routine of maintenance dredging will continue.
During the maintenance dredging, measures will be taken to minimise disturbance of the sediment, and to contain the migration of sediment. These include:
Encourage the contractor to use methods which minimise sediment disturbance and migration. This includes ensuring that the best practice and plant are used in the design and execution of the works – e.g. appropriate choice of plant such as:
• using Trailer Suction Hopper Dredger (TSHD), Cutter Suction or Backhoe
• Adherence to dredging licence conditions.
• Disposal of the dredgings at a licenced disposal site, Rame Head.
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Physical damage to habitats as a result of pollution or toxic contamination
Maintenance dredging has the potential to re-mobilise contaminated sediment and re-deposit it on SAC habitats or the contaminants could leach out of the sediment into the water column, affecting water quality. The Site will be used for storage and delivery of very large quantities of fuel, and the intake of fuel contaminated water from ships (as is the case for the existing jetty). There is therefore also the potential risk from spilt fuel (diesel and AVCAT), polluted surface water run-off in the event of a pollution incident and fire-fighting foam to enter the Estuary.
As noted in Section 2.4.3, there are currently nine concrete lined moats throughout the site that are designed to capture any major spillage from the AVCAT, diesel and sullage tanks and contain it on site. The site also currently contains several OWSs that act as interceptors to prevent oil from being discharged from site to the Hamoaze. All OWSs are fitted with oil in water detectors and alarms.
If any leaks do occur then they will probably be associated with the joints required for valves and manifolds. All other pipework will be continuously welded and checked for thinning on a regular basis either by intelligent “PIGs” or external Non-Destructive Testing (NDT). The new jetty head will place all valves and manifolds above a containment tank which will be regularly drained by suction pump into the sullage line. The same containment will also be necessary for the fuel filters located on land at the jetty root.
In addition to the above, a french drain is proposed to contain any leakage from the pipes as they emerge from the protection of the moat arrangement. This drain will be located downhill and, coupled with a new gully will pass any surface water contamination into a new 55,000litre oil water separator with a pumped connection into the current jetty car park OWS. Discharge from these OWSs will be along the jetty approach span as is currently permitted.
The Thanckes site currently maintains an emergency response spillage trailer which sits on hard standing to the east of the site main entrance. The trailer contains items such as: • Absorbent pads • Absorbent booms • Strainers • Disposable bags There is also a major spillage kit on site, which is located in the foam store to the east of the main site entrance. The major spillage kit contains items such as: • Sandbags • Drain blockers • Spill dry granules There are also smaller spill kits in the following locations: • Jetty head • Jetty filter bed • AVCAT loading bay • Diesel loading bay • Sullage loading bay transfer pump • Diesel pump area
Chapter 5 assesses the potential for dredging to add significant sediment loads to the estuary and the risk of pollution incidents during operation as small provided the mitigation detailed
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within that chapter is adhered too. In addition to the mitigation outlined above, these measures include:
• Secondary containment on the jetty head. • Real time pipeline/hose contents monitoring. • Intercepted drainage and bunding at foot of jetty and around filter beds. • Emergency isolation valves (dual manual/automated). • Run off water collection and disposal. • Pressure monitoring and thermal relief. • Accumulators to regulate pressure in the pipelines. • Procedure for controlling the delivery of fuel, including communication between the fuel storage point and the jetty head. The current dredging licence includes the following condition, which will prevent marine pollution incidents. It is anticipated that this condition will also be included in any new maintenance dredging licence, and will be adhered to:
• The licence holder must install bunding and/or storage facilities to contain and prevent the release of fuel, oils and chemicals associated with plant, refuelling and construction equipment, into the marine environment. i.e. secondary containment should be used with a capacity of not less than 110% of the containers storage capacity.
The proposed Development will upgrade and modernise the existing infrastructure, substantially reducing the environmental risks during operation.
Chapter 5 also assessed the risk of toxic contamination leaching into the water column as low due to the low leachability of the sediment.
Bird species associated with Tamar Estuaries Complex SPA, Lynher Estuary SSSI, St John’s Lake SSSI
Disturbance to birds by maintenance dredging
Maintenance dredging takes place for a short period of time (a matter of weeks) over the winter. The most recent maintenance dredge was in 2005. The distance of over 300m from the closest intertidal habitats that could be used by birds to the dredge location, combined with the fact that the estuary is already subject to a degree of disturbance from boat traffic and during re-fuelling operations at the jetty, means that the potential impacts of disturbance as a result of maintenance dredging are considered to be low. In addition, it has been established that the intertidal areas closest to the jetty are not optimum foraging habitat, and it is therefore considered unlikely that significant aggregations of any birds will be using this habitat over winter. No specific mitigation is therefore proposed.
Disturbance to birds by re-fuelling operations
The replacement of the jetty will not result in an increase in re-fuelling operations. The usage is expected to remain the same as at present. The numbers of birds associated with the habitats adjacent to the jetty are already low, and birds present in that area will either be habituated to
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disturbance by re-fuelling operations, or will be able to move to areas close by which are less disturbed. No specific mitigation is therefore proposed.
Physical damage to habitats as a result of increased siltation, pollution or toxic contamination from maintenance dredging
Implementation of the mitigation outlined above for the Plymouth Sound and Estuaries SAC should reduce the potential for any damage to habitats used by over-wintering birds for foraging or roosting.
Whitsand and Looe Bay MCZ
Physical damage to habitats and species as a result of increased siltation
A similar routine of maintenance dredging as is currently carried out will continue post- construction and it anticipated that the conditions of the current maintenance dredging licence will be included on any new licences. These include:
• No disposal is to take place at the disposal site from four hours before high water at Devonport until the time of high water at Devonport.
• The licence holder must ensure material is disposed of to the south-west corner of the Rame Head disposal site.
These measures will minimise the potential for movement of suspended sediment in a northerly direction, towards the MCZ.
Seagrass beds
Loss and damage of habitat by maintenance dredging
Maintenance dredging operations have the potential to affect Seagrass beds by an increase in suspended sediment and sediment deposition causing smothering of habitats. Mitigation proposals outlined above for the Plymouth Sound and Estuaries SAC which aim to minimise sediment deposition and dispersal during dredging and are applicable to this key ecological receptor.
Loss and damage of habitat by pollution
The risk of a pollution incident, particularly oil/fuel spillages or the use of firefighting foam during operation could damage seagrass beds. Maintenance dredging has the potential to re-mobilise contaminated sediment and re-deposit it on seagrass beds or the sediments could leach out of the sediment into the water column affecting the water quality. The measures outlined above for the Plymouth Sound and Estuaries SAC to reduce the risk of a pollution incident or toxic contamination occurring are considered suitable mitigation for this key ecological receptor. Furthermore, the new, upgraded facility will reduce the potential for an incident to occur.
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Migratory fish (Atlantic salmon, allis shad, European smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey)
Disturbance to migratory fish by maintenance dredging
Noise from maintenance dredging could present a physical barrier to movement of fish up and down the estuary if carried out during the migratory period. The current maintenance dredging regime only carries out dredging during the winter period (December to March) to avoid disturbance to migratory fish and, where possible, in-channel dredging is avoided during February and March to avoid impacts on European smelt. It is anticipated that this will continue and therefore no further mitigation is required.
Loss and damage to foraging habitats as a result of increased siltation and pollution from maintenance dredging
The maintenance dredging is undertaken outside of the fish migratory period. As outlined earlier, mitigation measures are to be put in place to minimise sediment remobilisation and movement and to reduce the risk of any pollution incident. Furthermore, the new, upgraded facility will reduce the potential for an incident to occur. The effects of any sediment movement and pollution during operation are likely to be localised both spatially and temporally, therefore by the time fish migration is underway, localised effects will no longer be significant. No specific mitigation is therefore required.
Other fish species (bass, lemon sole, sole, sprat, monkfish, mackerel, spurdog, whiting)
Disturbance to resident fish species by maintenance dredging
It is considered that the high levels of noise and vibration that already exist in the Estuary mean that the short periods of maintenance dredging over intermittent winters will not cause any significant long term effects on resident fish species. In addition, the fish are mobile species which means that they can move quickly away from any disturbance. It is therefore considered that no further mitigation is required.
Damage to spawning habitat for resident species as a result of maintenance dredging, pollution and toxic contamination
The timing of maintenance dredging throughout the winter means that any adverse effects through sediment dispersal will no longer be significant by the time of the main spawning season for lemon sole (April-September), sole (March to May, peaking in April) and sprat (May to August).
The mitigation measures outlined above for the Plymouth Sound and Estuaries SAC to minimise sediment disturbance and re-deposition are considered relevant for this key ecological receptor.
In addition, the mitigation measures outlined to reduce the risk of a pollution incident entering the estuarine environment are also considered applicable to this key ecological receptor. Furthermore, the new, upgraded facility will reduce the potential for an incident to occur.
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Marine mammals (bottlenose dolphin, harbour porpoise and grey seal)
Disturbance from maintenance dredging
The intermittent and short length of time over which maintenance dredging takes place, combined with the infrequent sightings of marine mammals means that it is considered highly unlikely that any cetaceans or seals will be present in the Estuary during dredging operations. However, should any marine mammals be present, they will easily be able to move away from any significant disturbance. No specific mitigation to reduce potential impacts on marine mammals is therefore proposed.
Otters
The distance of the dredging from the shore, combined with the intermittent and short length of time which maintenance dredging takes place, means that is it considered highly unlikely that any otters commuting past the jetty will be adversely affected by the dredging.
Operational lighting will be as existing, areas of dark foreshore will be maintained enabling access by otters at all times. No specific mitigation to reduce potential impacts on otters is therefore proposed. 6.7 Assessment of Effects 6.7.1 Construction
Subtidal mudflats associated with Plymouth Sound and Estuaries SAC
Loss of habitat
The construction of a new jetty, dolphin moorings and the extension of the dredge pocket will result in the permanent loss of subtidal estuarine habitats. It is anticipated that the area beneath the piles will be approximately 0.018ha, this habitat loss will be balanced by the habitat that would be restored when the existing piles, which cover an area of 0.009ha, would be removed. Consequently, there would be a net loss of 0.009ha as a result of piling.
The proposed berth pocket is the same size as the existing berth pocket (1.35ha) and there is an overlap of 0.92ha between the existing and the new, resulting in 0.43ha of currently un- dredged habitat to be removed. An additional 0.3ha would also be lost during the capital dredge where the proposed berth pocket sides would slope. In relation to the proposed berth pocket, this results in a net loss of 0.73ha, and a total dredge area of 1.65ha (= 0.92ha + 0.43ha + 0.3ha).
Some dredging will also need to be carried out to enable access to the western side of the jetty over an area of 1.36ha (the Northern Approach channel).
Habitat diversity may also be limited through increased shading as a result of the presence of the jetty (particularly in shallower waters). However, the removal of the existing jetty structure
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should ensure the restoration of SAC habitats within the now unshaded area. The existing jetty covers an area of approximately 0.2ha and the new jetty will cover an area of 0.32ha, so only an additional 0.12ha would be shaded by the proposed jetty. However, given that seagrass was recorded in the intertidal area (outside of the SAC) beneath the existing jetty it is not considered that the shading would lead to habitat loss.
The net permanent loss of habitat as a result of dredging and piling will therefore be 2.399ha. This is shown in Table 6-8.
Table 6-8 Current and anticipated habitat loss
Aspect Temporary Damage Net Permanent Loss Jetty area of piles (approx) 0.018ha 0.009ha (0.018ha – 0.009ha, the area of the existing piles to be removed) Berth Pocket dredging 1.65ha (1.35ha for berth pocket + 0.73ha 0.3ha where berth pocket sides slope) Western navigation channel 1.36ha 1.36ha dredging (the Northern Approach Channel) Total Area 3.028ha 2.099ha
The total marine and estuarine habitat feature of Plymouth Sound and Estuaries SAC is 5762.07ha, and 2.099ha represents 0.04% of the total available marine and estuarine habitat within the SAC. Although the habitats to be lost are within the SAC, the habitats were impoverished and no significant numbers of important species were identified.
Current construction methodology includes proposals to side-cast arisings from pilings adjacent to the new subtidal piles only (to reduce impacts on intertidal habitats, particularly seagrass beds, where the piles fall outside of the contaminated area at the proposed jetty head. The approximate volume of arisings to be side-cast is 250m 3. Information in Appendix 6-C (Results of the marine surveys) indicates that the sublittoral sediments in the area of the jetty are impoverished due to the historical and current heavy industrial use of the estuary and the dredging regime. It is considered that the placing of this small volume of arisings close to the new piles in subtidal habitats is unlikely to result in permanent habitat loss due to the naturally turbid nature of the estuary and that any impact will be localised and temporary. Side casting will also retain sediment within the estuary and thereby not reduce the sediment budget.
The minimal loss of impoverished habitat is classified as having No significant effect on this feature of International importance .
Physical damage to habitats as a result of increased siltation, release of contaminants from contaminated sediment and pollution
Construction activities, in particular piling and dredging, have the potential to temporarily add sediment loads to the estuary.
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However, the estuary is naturally a turbid and silty environment. A study to assess the impacts of dredging on the Tamar Estuary (Ref 6-14) stated that maintenance dredging in the lower Tamar accounts for the annual removal of between 5,000 and 200,000 tonnes of dry sediment per year. Each day, a semi-diurnal tide of average range mobilises approximately 5000m 3 of sediment in the upper Tamar Estuary. In addition, on a seasonal cycle, changes in river flow cause bed sediment with an estimated volume of 164,000m 3 to migrate up the estuary in summer (low river flow) and down again in winter (high river flow). A fairly recent (2011) study into the dredging regime of Plymouth Estuary (Ref 6-15) described the Tamar as a macro-tidal estuary which is subject to climatic and tidal variations that influence sediment transport. These variations can be on a daily to seasonal temporal scale. The study found that during the winter, mobile sediment was more abundant in the lower reaches of the Estuary, with silt content increasing to around 80% at the mouth of the Estuary, and in the summer, sediment accumulates at the head of the Estuary. This was attributed to changes in flow conditions resulting in much of the accumulated sediment at the head of the estuary being flushed to re- charge mid-estuary.
The potential exists for pollution, in particular fuel/diesel spillages to be released from construction works affecting water quality and nearby SAC habitats. Other potential sources of pollution include fuels and oils from construction equipment, materials such as cements and concrete, construction waste (solid waste and wastewater) and debris from the demolition of the existing jetty. Dredging may also remobilise sediment containing toxic materials such as TBT, heavy metals and hydrocarbons, causing it either to be re-deposited elsewhere or to leach into the water environment. Chapter 5 Water, Contamination and Sediment Quality addresses the possible effects of the proposed Development on the water environment through the release of contaminants into the water (through dissolution or suspension) and concluded the following: • Elevated concentrations of metals and hydrocarbons already present in the sediments mean that any small release of contaminant during the construction works is unlikely to have a significant impact.
• During the construction works, disturbance of the sediment at any one location will be localised and of short duration so that any locally elevated concentrations not identified will have a limited impact.
• Leachability testing indicated that the release of contaminants in the sediment into the water is unlikely to occur.
As such, the risk of damage caused by the release of contaminated sediment is considered to be low. Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of sediment, contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary.
Physical damage to SAC habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of International importance .
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Bird species associated with Tamar Estuaries Complex SPA, Lynher Estuary SSSI, St John’s Lake SSSI
Disturbance to SPA features by piling
An assessment of baseline conditions has indicated that the areas of intertidal habitat closest to the existing jetty (near Wilcove to the north and Thanckes Lake to the south) support small numbers of on-passage little egret (an SPA qualifying feature) (a maximum of three birds were observed during surveys) and may support low numbers of little egret over-winter. The SPA is located approximately 1.5km to the south and 2km to the west of the Site. NE in its detailed advice setting out how it has identified the conservation objectives for the SPA (Ref 6-16), include an objective relating to disturbance in roosting/feeding areas, the target being ‘no significant reduction in numbers (of little egret) or displacement of birds from an established baseline, subject to natural change’.
Disturbance (which may be visual, noise or vibration) can result in a variety of responses, but birds typically take flight expending unnecessary energy before resuming activity in the same area or relocating to adjacent areas. The overall effect on a bird population is dependent on a range of factors including: the frequency of disturbance, habituation and toleration to disturbance, availability of other suitable habitat and the number of birds (if adjacent areas are at their carrying capacity).
It is predicted that the greatest potential for disturbance to over-wintering birds will be from noise generated from the percussive piling, particularly as piling is planned to be carried out between September and March. Chapter 8 Noise includes a baseline noise assessment that confirms background noise levels at five receptor sites (between 480m and 780m from the existing jetty) are between 33.2 and 40.8dBL Aeq T during the night and 45 and 53.6dBL Aeq T during the day indicating generally low levels of noise. Modelling has been undertaken of construction noise (including piling) and the cumulative impacts of unmitigated noise of piling the jetty approach, the jetty head and the mooring dolphins simultaneously has been assessed as being 84.1dBL Aeq at 50m from source, dropping to 68.5dBL Aeq at 300m from the source (see Table 6-9).
Table 6-9 Cumulative unmitigated noise impacts of piling the jetty approach, the jetty head and the mooring dolphins
Distance from 50 100 150 200 300 jetty (m)
LA eq dB(A) 84.1 78.1 74.6 72.1 68.5
A study on the responses of wading birds and wildfowl by the University of Hull (Ref 6-17) showed that construction noise levels should be restricted to below 70dB as these birds will habituate to regular noise below this level. Where possible sudden irregular noise above 50dB should also be avoided as this causes disturbance to birds.
Although BTO core count data cannot provide an indication of the spatial distribution of the birds within a count sector, the peak numbers of little egret recorded (5) for the Tamar Estuary (South) Sector 10 are considered to be small when taking into account the entire count sector (which covers an area of approximately 390ha and extends north from the Site to the Tamar Bridge (approximately 3km away) and south to Torpoint ferry crossing, a distance of
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approximately 940m). In addition, the area of foraging/roosting habitat likely to be affected by unmitigated noise impacts (approximately 300m to the north and 300m to the south of the existing jetty) is also extremely small when compared to the count sector as a whole and indeed the Tamar Estuaries Complex SPA. The fact that the intertidal mudflats around Thanckes jetty are not designated also indicates that the foraging habitat is sub-optimal (reflected by the results of the marine surveys which indicated an impoverished benthic flora). This reduces further the possibility that significant aggregations of little egret will occur in close proximity to the proposed Development. As the intertidal habitats within 300m of the proposed Development are unlikely to support significant numbers of little egret, no specific mitigation is proposed to avoid disturbance to overwintering little egret.
The Site is considered to be subject to a certain degree of disturbance from boat traffic and during re-fuelling operations. There is sufficient habitat close by and throughout the estuary to ensure that should any little egret be disturbed by piling works, they can easily move away and should suffer no long term damage or behavioural changes. The piling works are temporary and any effects are reversible, i.e. once complete, little egret may return to the habitats around the jetty.
Disturbance to SPA features (specifically over-wintering little egret) by piling are classified as having No significant effect on this feature of International importance.
Disturbance to SSSI features by piling
No specific mitigation measures are proposed to address any potential impacts on waders or wildfowl that may use the habitats adjacent to the jetty, which are functionally linked to the nearby SPA habitats, as it is considered that the habitats adjacent to the jetty are unlikely to support significant numbers of birds due to habitat quality and the amount of disturbance the area is subject to. There is sufficient habitat close by and throughout the estuary to ensure that should any birds be disturbed by piling works, they can easily move away and should suffer no long term damage or behavioural changes. The piling works are temporary and any effects are reversible, i.e. once complete, birds may return to the habitats around the jetty.
St John’s Lake SSSI and Lynher Estuary SSSI are both of a sufficient distance away that any birds using the SSSI habitats will not be disturbed by piling works.
Disturbance to SSSI features by piling is classified as having No significant effect on this feature of National importance.
Disturbance from other construction activities
The demolition of the existing jetty and land-based infrastructure is planned for between February 2018 and August 2018, just within the on-passage period and wintering period. The activities likely to be occurring during February (wintering) and August (on-passage) may include the cutting off of piles at the seabed, or below, using hydraulic shearing cutters for concrete piles and either mechanical cutters or water jet cutting for steel piles. All the machinery will be operated from marine plant. Noise modelling as set out in Table 6-10 below has indicated that the cumulative noise impact of all the plant used for demolition (including hydraulic breakers, dumpers and plate compactors) is above 70dBL Aeq T until 200m from the source of the noise.
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Table 6-10 Cumulative unmitigated noise impacts during demolition
Distance from 50 100 150 200 300 jetty (m)
LA eq dB(A) 81.5 75.5 72 69.5 65.9
However, is anticipated that the noise from this activity will be significantly less than the cumulative impacts table illustrated above.
August to October is the peak on-passage period for little egret. By the time the on-passage little egret arrive the majority of the demolition will be completed.
The mudflats around the jetty have already been assessed as not being a key foraging or roosting resource for little egret and other species associated with the SSSIs due to habitat quality and the degree of disturbance the area is already subject to. The construction activities are temporary and any effects are reversible, i.e. once complete, birds may return to the habitats around the jetty. No specific mitigation is therefore proposed.
Disturbance to birds from other construction activities is classified as having No significant effect on this feature of International importance.
Loss and damage to foraging habitats as a result of increased siltation and pollution
Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary.
Loss and damage to foraging habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of International importance .
Whitsand and Looe Bay MCZ
Physical damage to habitats and species as a result of increased siltation
The capital dredging will result in 37,000m 3 (13066 tonnes) of sediment being deposited at Rame Head. This is a relatively small volume when compared to the current maintenance dredge licence for HMNB Devonport (to which the site is linked), which allows for the deposition of 367,000 tonnes of sediment at Rame Head over a three year period. Cefas have undertaken studies in relation to the impact of disposal of dredged material at Rame Head, and published a report of findings in 2005 (Ref 6-18). These studies determined that whilst there may be some minor local and temporary increases in turbidity resulting from disposal operations, evidence from the monitoring surveys indicates that any environmental effects of deposited dredged material are largely confined to the immediate vicinity of the licence disposal site. Sediment transport modelling undertaken by Cefas, and described in their report (Ref 6-18), predicted the location of the deposition of disposed material settling out following the release of individual hopper loads. The results indicated that the sediment accumulation onto the seabed direct from
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the disposal operation tends to occur in a band parallel to the shore, with only very limited transport in an inshore direction.
The results of the Cefas monitoring, together with the mitigation measures outlined in 6.6.1 above, have resulted in a conclusion of No significant effect on this feature of National importance .
Seagrass beds
Loss and damage of habitat by piling and dredging
Construction of the jetty will result in the permanent loss of seagrass beds on the intertidal zone through the installation of piles. The results of the intertidal surveys indicated that seagrass was locally abundant under the footprint of the proposed Development, but the plant growth was sparse. It is considered that the seagrass beds are unlikely to be completely shaded by the presence of the new jetty, as seagrass beds were present beneath the existing jetty. The removal of the existing jetty structure should ensure the restoration of seagrass habitats in the area that would no longer be shaded by the jetty. The existing jetty covers an area of 0.2ha and the new jetty will cover an area of 0.33ha, so only an additional 0.13ha would be beneath the proposed jetty. This is not considered to be significant given the sub-optimal quality of the habitat and the availability of good quality habitat in the wider area. Notwithstanding this, restoration of seagrass will be encouraged by removing crabbing tiles from the intertidal area within the DIOs control and reducing bait digging and crabbing by installing new signage to discourage these activities.
Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary.
Measures to ensure that a small amount of uncontaminated arisings from piling on intertidal habitat and 10m into the subtidal zone are removed to subtidal areas (around other piles) as far as is possible from the intertidal zone will also reduce the risk of sediment re-deposition on the intertidal area.
Loss and damage to Seagrass habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of County importance .
Migratory fish (Atlantic salmon, allis shad, European smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey)
Disturbance/mortality to migratory fish
Piling works associated with the construction of the new jetty head and the new mooring dolphins could act as an acoustic barrier to fish migration if carried out during the core migratory period. In addition, impact sound from any piling undertaken during the migratory period could adversely affect the health of fish or adult eels if they are exposed to it for a sufficiently long time and intensity. Underwater noise and light from the demolition of the existing jetty could disturb migratory fish.
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Noise affects fish species in different ways. Species with swim bladders (e.g. shad and salmonids) are comparatively more vulnerable to underwater noise than those without (Ref 6- 19). Fish typically exhibit an initial startle response when initially exposed to a sound source and may temporarily avoid adverse areas. Close to a strong sound source, however; fish may suffer physiological damage and may be killed if in very close proximity.
Percussive piling works associated with the construction of the new jetty head and the new mooring dolphins are to be undertaken outside of the main migratory fish period for allis shad, Atlantic salmon, sea trout, European eel and sea lamprey (i.e. will take place between September to March).
European smelt accumulate in the lower estuary from October onwards, before ascending to spawn in the River Tamar between February and April. The February and March migratory months of the European smelt coincide with the window available for percussive piling. However, no percussive piling will take place during April, and it is considered by NE (email dated 14 th February 2014, see Appendix 6-G) that the time available is sufficient to allow smelt to move pass the proposed Development to their spawning grounds.
Vibro-piling, pile case oscillation and auguring/drilling typically generate significantly lower noise levels in comparison with percussive piling, and NE and Cefas are in agreement that these construction methods can be carried out at any time of year, subject to monitoring of initial operations outside of the core sensitive period of 1st April to 31 st August to confirm noise levels are within the range predicted.
Noise and vibrations from demolishing the existing jetty are expected to be lower than piling, and significant adverse impacts are not anticipated.
Furthermore, no night time working will be carried out.
Disturbance/mortality to migratory fish through pile demolition is classified as having a No significant effect on this feature of International importance .
Loss and damage to foraging habitats as a result of increased siltation and pollution
Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary and will have dispersed by the time the migratory fish season begins.
During pile removal some localised sediment disturbance is expected as it needs to be removed to allow access to the pile. However, this is expected to be extremely localised and of such a short duration that no specific mitigation is proposed.
Loss and damage to foraging habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of International importance .
Other fish species (bass, lemon sole, sole, sprat, monkfish, mackerel, spurdog, whiting)
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Disturbance/mortality to resident fish species
It is highly likely that fish that are resident in the Tamar Estuary are already subject to a high degree of noise and vibration from commercial, naval shipping and recreational vessels, in addition to routine maintenance dredging. Therefore local populations of fish are likely to be habituated to underwater noise and vibration.
Flatfish (i.e. sole and lemon sole), sharks (i.e. spurdog) and some pelagic species such as mackerel and sprat do not possess swim bladders and are therefore comparatively less susceptible than those species which do, i.e. bass and whiting. The entire estuary is a designated bass nursery all year round, although the majority of bass larvae arrive in the estuary between June and August and are found as young fish in large shoals in shallow waters of tidal pools, saltmarshes and marinas before moving to slightly deeper water nearby for the winter. Young bass normally stay close inshore for approximately four years before moving into wider coastal areas for a year as ‘school bass’ before coming fully mature.
No specific mitigation is proposed as it is considered that the high levels of noise and vibration that already exist in the Estuary mean that the relatively short period of piling over winter from December to March will not cause any significant long term effects on those resident fish species with swim bladders (bass and whiting). In addition, the fish are mobile species which means that they can move quickly away from any significant disturbance.
Disturbance/mortality to resident fish as a result of piling is classified as having No significant effect on these features of Regional importance .
Loss and damage to spawning habitat for resident species
The timing of piling and dredging throughout the winter avoids the spawning season for lemon sole, sole and sprat. Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary and will have dispersed by the time the spawning season begins.
Given that the Site occupies 0.06% of the total estuarine habitat available in the Tamar Estuary, the direct loss of breeding and spawning habitat through construction of the jetty, or by capital dredging, will be negligible. It is also considered that the habitats under the existing jetty and within the existing dredge pocket are unlikely to support spawning habitat for resident species due to their disturbed and turbid nature.
Loss and damage to spawning habitat for resident fish as a result of construction is classified as having No significant effect on these features of Regional importance .
Loss and damage to foraging habitats as a result of increased siltation and pollution
The re-distribution of sediment beyond the immediate piling and dredge pocket may smother feeding areas, although a high degree of tolerance will be expected given the naturally turbid conditions within estuaries. Any smothering effects would also be temporary as subsequent tidal movements will re-mobilise any settled fine sediment.
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Providing the mitigation measures outlined in Section 6.6.1 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. Any smothering effects would also be temporary as subsequent tidal movements will re-mobilise any settled fine sediment. No long term damage to any fish foraging habitat is anticipated as a result of the proposed Development.
Loss and damage to foraging habitat for resident fish as a result of construction is classified as having No significant effect on these features of Regional importance .
Marine mammals (bottlenose dolphin, harbour porpoise and grey seal)
Disturbance from piling and dredging
Cetaceans (dolphins and porpoises) are susceptible to underwater noise, particularly pile- driving, as it can affect their ability to echo-locate through masking their vocalisations causing behavioural modifications such as temporary displacement from the area where the pile-driving is taking place (Ref 6-20).
However, percussive piling will only take place between April and August, with the lower impact vibro-piling technique taking place throughout the year. Should any cetacean enter the Estuary when the piling is taking place, it will be able to move away from any noise, although the likelihood of cetaceans being present is considered to be low as records in the vicinity of the proposed Development are rare.
There are no known hauling out sites for grey seals in the vicinity of the development and should any grey seal find itself in the vicinity of the proposed Development it will be able to move away. The likelihood of grey seals being present is considered to be low as records in the vicinity of the proposed Development are rare.
No specific mitigation is proposed to reduce any potential impacts on marine mammals (dolphins, porpoises and grey seals) as they are considered to occur so infrequently in the Tamar that it is extremely unlikely any will be found during piling over the winter months (as most sightings are during the summer months).
Disturbance from piling and dredging is classified as having No significant effect on these features of District/Borough importance . 6.7.2 Operation
Subtidal mudflats associated with Plymouth Sound and Estuaries SAC
Physical damage to habitats as a result of increased siltation
The existing berth pocket is dredged intermittently (last dredged in 2005) to maintain the minimum depth. The potential exists for increased sediment loads to be released from maintenance dredging works affecting water quality and nearby SAC habitats.
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Providing the mitigation measures outlined in Section 6.6.2 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, will be localised and temporary.
Physical damage to SAC habitats as a result of increased siltation is classified as having No significant effect on this feature of International importance .
Physical damage to habitats as a result of pollution or toxic contamination
Maintenance dredging has the potential to re-mobilise contaminated sediment and re-deposit it on SAC habitats or the contaminants could leach out of the sediment into the water column, affecting water quality. There is also the potential risk from spilt fuel (diesel and AVCAT), polluted surface water run-off in the event of a pollution incident and fire-fighting foam to enter the Estuary.
Provided the mitigation measures outlined in Chapter 5 and Section 6.6.2 are adhered to, it is predicted that there will be no long term adverse impact on SAC habitats as a result of pollution or toxic contamination. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur. This impact is classified as having No significant effect on this feature of International importance .
Bird species associated with Tamar Estuaries Complex SPA, Lynher Estuary SSSI, St John’s Lake SSSI
Disturbance to birds by maintenance dredging
No specific mitigation is proposed due to the short period of time that maintenance dredging takes over winter. The most recent maintenance dredge was in 2005. In addition, it has been established that the intertidal areas closest to the jetty are not optimum foraging habitat for wildfowl and waders, so it is considered unlikely that significant aggregations of any birds will be using this habitat over winter.
Disturbance to birds as a result of maintenance dredging is classified as having No significant effect on these features of International and National importance .
Disturbance to birds by re-fuelling operations
No specific mitigation is proposed as an increase in re-fuelling operations is not expected once the new jetty is operational. The numbers of birds associated with the habitats adjacent to the jetty are already low, and birds present in that area will either be habituated to disturbance by re-fuelling operations, or will be able to move to areas close by which are less disturbed.
Disturbance to birds as a result of re-fuelling operations is classified as having No significant effect on these features of International and National importance .
Physical damage to habitats as a result of increased siltation, pollution or toxic contamination from maintenance dredging
Providing the mitigation measures outlined in Section 6.6.2 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is
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reduced. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary.
Loss and damage to foraging habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of International importance .
Whitsand and Looe Bay MCZ
Physical damage to habitats as a result of increased siltation
A similar routine of maintenance dredging as is currently carried out will continue post- construction. The last dredge event was in 2005, when 4036m 3 (1425 tonnes) was dredged, and it is anticipated that any future licences will include conditions to minimise the potential for movement of suspended sediment in a northerly direction, towards the MCZ, as is currently the case. Cefas have undertaken studies in relation to the impact of disposal of dredged material at Rame Head, and published a report of findings in 2005 (Ref 6-18). These studies determined that whilst there may be some minor local and temporary increases in turbidity resulting from disposal operations, evidence from the monitoring surveys indicates that any environmental effects of deposited dredged material are largely confined to the immediate vicinity of the licence disposal site. Sediment transport modelling undertaken by Cefas, and described in the above mentioned report, predicted the location of the deposition of disposed material settling out following the release of individual hopper loads. The results indicated that the sediment accumulation onto the seabed direct from the disposal operation tends to occur in a band parallel to the shore, with only very limited transport in an inshore direction.
These findings, together with the mitigation measures outlined in 6.6.1 above, have resulted in a conclusion of No significant effect on this feature of National importance .
Seagrass beds
Loss and damage of habitat by maintenance dredging
Providing the mitigation measures outlined in Section 6.6.2 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary.
Loss and damage to Seagrass habitats as a result of maintenance dredging are classified as having No significant effect on this feature of County importance .
Loss and damage of habitat by pollution
The risk of a pollution incident, particularly oil/fuel spillages or the use of fire fighting foam during operation could damage Seagrass beds. Providing the mitigation measures outlined in Section 6.6.2 are implemented, the risk of a pollution incident occurring are considered to be reduced to an acceptable level. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur.
Loss and damage to Seagrass habitats as a result of pollution are classified as having No significant effect on this feature of County importance .
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Migratory fish (Atlantic salmon, allis shad, European smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey)
Disturbance to migratory fish by maintenance dredging
The current maintenance dredging regime is only undertaken during the winter period to avoid disturbance to migratory fish. It is anticipated that this will continue and therefore no further mitigation is required.
It is considered that mitigation through avoidance means that disturbance/mortality to migratory fish as a result of maintenance dredging is classified as having No significant effect on this feature of International importance .
Loss and damage to foraging habitats as a result of increased siltation and pollution from maintenance dredging
Providing the mitigation measures outlined in Section 6.6.2 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur. The estuary is naturally a turbid and silty environment, therefore should any impacts arise from increased sediment loads and pollution, they will be localised and temporary and will have dispersed by the time the migratory fish season begins.
Loss and damage to foraging habitats as a result of increased siltation and pollution are classified as having No significant effect on this feature of International importance .
Other fish species (bass, lemon sole, sole, sprat, monkfish, mackerel, spurdog, whiting)
Disturbance to resident fish species by maintenance dredging
No specific mitigation is proposed as it is considered that the high levels of noise and vibration that already exist in the Estuary mean that the short period of maintenance dredging in occasional winters will not cause any significant long term effects on those resident fish species with swim bladders (bass and whiting). In addition, fish are mobile species which means that they can move quickly away from any significant disturbance.
Disturbance/mortality to resident fish as a result of maintenance dredging classified as having No significant effect on these features of Regional importance .
Damage to spawning habitat for resident species as a result of maintenance dredging, pollution and toxic contamination
Providing the mitigation measures outlined in Section 6.6.2 are implemented, it is considered that the risk of large volumes of contaminated sediment or pollution entering the estuary is reduced. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur. Any smothering effects would also be temporary as subsequent tidal movements will re-mobilise any settled fine sediment. No long term damage to any fish foraging habitat is anticipated as a result of maintenance dredging or any pollution incident.
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Loss and damage to foraging habitat for resident fish as a result of construction is classified as having No significant effect on these features of Regional importance .
Marine mammals (bottlenose dolphin, harbour porpoise and grey seal)
Disturbance from maintenance dredging
No specific mitigation is proposed to reduce any potential impacts on marine mammals (dolphins, porpoises and grey seals) as they are considered to occur so infrequently in the Tamar that it is extremely unlikely any will be encountered during maintenance dredging over the winter (as most sightings are during the summer months).
Disturbance from piling and dredging is classified as having No significant effect on these features of District/Borough importance . 6.8 Cumulative Effects
There are three developments which will be considered for cumulative impacts. These are:
• MOD Forward Operating Base at Kinterbury Point;
• MOD Refurbishment and Operation of Trevol Jetty;
• South West Devon Waster Partnership Combined Heat and Power Plant.
Refer to chapter 3.8 for details of these developments.
The Kinterbury Point project involves the creation of a FOB at Kinterbury Point, within HMNB Devonport, for the FHSU which transfers naval staff to vessels. The HRA for the Kinterbury Point (Ref 6-21) project assessed the significance of effects of the proposals on the Plymouth Sound and Estuaries SAC and the Tamar Estuaries Complex SPA. Potential hazards identified include the risk of pollution from aircraft maintenance and refuelling, risk of crash and risk of disturbance to overwintering avocet and overwintering and on passage little egret. However, implementation of robust pollution prevention and control measures would result in a low likelihood of a pollution incident, and neither little egret nor avocet were recorded feeding or roosting in the vicinity of Kinterbury Point, As such, the HRA concluded that no likely significant negative effects would occur as a result of the proposals. The Kinterbury Point project is unlikely to affect any of the Key Ecological Receptors identified in relation to Thanckes, and as such there will be no cumulative adverse effects on ecology as a result of the proposed developments. The Trevol Jetty project involves the refurbishment and operation of Trevol Jetty at HMS Raleigh. NE are concerned that in combination with the temporary interim increase in helicopter activities at HMS Raleigh there will be disturbance to the bird assemblage in St John’s Lake. The MOD does not consider that operational use of the jetty is likely to cause significant disturbance to avocet or little egret feeding or roosting in St John’s Lake due to the distance from the significant roosting areas and the low usage of this jetty by personnel. However, the MOD has committed to plant screening along the shoreline in the vicinity of Trevol Jetty as a mitigation measure to reduce disturbance to the bird assemblage feeding in St John’s Lake. As the Site is not considered to be particularly important for birds associated with the surrounding designated sites, and as it is further from St John’s Lake than Trevol Jetty, it is
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unlikely that there will be cumulative adverse effects on ecology as a result of the proposed developments.
It is anticipated that the Combined Heat and Power Plant proposed at Weston Mill Lake would be a land-based project and as such cumulative adverse effects on marine ecological receptors as a result of the proposed developments are considered unlikely, assuming the implementation of standard pollution prevention measures. Given that the Site is not considered to be particularly important for birds associated with the surrounding designated sites, it is unlikely that there will be cumulative adverse effects on birds as a result of the proposed developments. The Weston Mill Lake site is across the estuary from the Site it is therefore not envisaged that the Power Plant would have any effect on the terrestrial habitats or species associated with the Site. 6.9 Enhancement measures
Although not required address significant effects on key ecological receptors, DIO are committed to their duties under the NERC Act (2006) which places a duty on public bodies to consider conservation of biodiversity within all of their actions. As such, the following enhancement measures are proposed:
• A programme of eradication will be implemented to remove Canadian Waterweed and Pirri-pirri-bur from the Site. This will enhance the biodiversity value of the site and will prevent invasive species from spreading into adjacent habitats.
• Consideration will be given to reusing the arisings from the dredging. This will be subject to further analysis of the material. It has been suggested that the material could be used to enhance the high tide roost at Sango Island in St John’s Lake which is currently submerged by the highest tides, or creating a new additional high tide roost here. However, this would be need to be subject to further assessments, as there would be implications for the Plymouth Sound and Estuaries European Marine Site. 6.10 Summary
The ecology chapter has assessed the likely significant effects of the Thanckes OFD Loading Facility and Fire Fighting Upgrade in terms of terrestrial and marine ecology, in accordance with the guidance set out in the IEEM Guidelines for Ecological Impact Assessment (2006) (Ref 6-1). Following a desk study, an extended Phase 1 habitat survey, ornithology surveys and a marine survey, as well as a consultation exercise, the baseline conditions and key ecological receptors were established.
The subtidal habitats within the Site are located within the Plymouth Sound and Estuaries SAC, and the subtidal mudflats associated with this designated site have been identified as a key ecological receptor. The proposed Development will result in the permanent loss of SAC habitat, as well as a reduction in habitat diversity as a result of shading by the new jetty. However, the area of habitat loss is minimal, and the marine survey identified the habitats as impoverished. In addition, the removal of the existing jetty structure should ensure the restoration of SAC habitats within the area that would no longer be shaded, and habitat restoration will be encouraged by removing crabbing tiles and discouraging crabbing and bait digging in the intertidal area within the DIOs control.
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The Tamar Estuaries Complex SPA and St John’s Lake SSSI are located approximately 1.4km south of the Site, and the Lynher Estuary SSSI is located approximately 2km to the west of the Site. The habitats within and adjacent to the proposed Development are not considered to support significant numbers of birds associated with these designated sites. There is sufficient habitat close by and throughout the estuary to ensure that, should any birds be disturbed during construction (particularly as a result of piling works), they can easily move away and should suffer no long term damage or behavioural changes. The piling works are temporary and any effects are reversible, i.e. once complete, birds may return to the habitats around the jetty.
The proposed disposal site for dredged material is Rame Head, located approximately 1.5km south of the Whitsand and Looe Bay MCZ. It is predicted that a similar routine of maintenance dredging as is currently carried out will continue post-construction. Any future licences are expected to include conditions to minimise the potential for movement of suspended sediment in a northerly direction, towards the MCZ, as is currently the case. Studies undertaken by Cefas have demonstrated that the current dredging regime does not have a detrimental effect on the Whitsand and Looe Bay MCZ.
A number of migratory fish species pass the Site, including Atlantic salmon which is a qualifying feature of Dartmoor SAC, alis shad which is a qualifying feature of Plymouth Sound and Estuaries SAC, and European smelt and European eel which are reasons for designation of Tamar Estuary MCZ. Key migratory periods for these species have been taken into consideration in programming the works, and percussive piling will take place outside of the main migratory fish period (i.e. not between April and August). Vibro-piling, pile case oscillation and auguring/drilling will be carried out at any time of year, subject to monitoring of noise levels.
The Plymouth Sound and Estuaries Complex SAC is part of a year-round designated nursery area for bass, and the Tamar Estuary is also a spawning area for lemon sole, sole and sprat, and a nursery area for monkfish, lemon sole, mackerel, spurdog and whiting. Given the high levels of noise and vibration that already exist in the Estuary, the relatively short period of piling will not cause any significant long term effects on these fish species.
Marine mammals are considered to occur so infrequently in the Tamar that no impacts on marine mammals are envisaged as a result of the proposals.
Increased siltation, release of contaminants from contaminated sediment and pollution during construction and operation has the potential to affect habitats within the Plymouth Sound and Estuaries SAC, seagrass beds and foraging habitats used by fish and birds associated with the SPA and SSSI’s. Mitigation measures have been proposed which would minimise disturbance of sediment, contain migration of sediment and reduce the risk of a pollution incident. It should be noted that the new, upgraded facility will reduce the potential for a pollution incident to occur.
No significant effects on any ecological receptors are anticipated as a result of the Development.
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Table 6-11 Ecology Impact Summary Table
Impact description Temporary/Permanent Significance rating
Construction
Plymouth Sound and Estuaries Permanent No significant effect on feature of SAC – Loss of habitat International importance
Plymouth Sound and Estuaries Temporary No significant effect on feature of SAC – physical damage to International importance habitats as a result of increased siltation, release of contaminants from contaminated sediment and pollution
Bird species associated with Temporary No significant effect on feature of the Tamar Estuaries Complex International importance SPA, Lynher Estuary SSSI, St John’s Lake SSSI – disturbance to SPA features by piling
Bird species associated with Temporary No significant effect on feature of the Tamar Estuaries Complex National importance SPA, Lynher Estuary SSSI, St John’s Lake SSSI – Disturbance to SSSI features by piling
Bird species associated with Temporary No significant effect on feature of the Tamar Estuaries Complex International importance SPA, Lynher Estuary SSSI, St John’s Lake SSSI – disturbance from other construction activities
Bird species associated with Loss – permanent No significant effect on feature of the Tamar Estuaries Complex Damage - temporary International importance SPA, Lynher Estuary SSSI, St John’s Lake SSSI – loss and damage to foraging habitats as a result of increased siltation and pollution
Whitsand and Looe Bay MCZ Temporary No significant effect on feature of – physical damage to habitats National importance and species as a result of increased siltation
Seagrass beds – Loss and Loss – permanent No significant effect on feature of damage of habitat by piling Damage - temporary County importance and dredging
Migratory fish – (Atlantic Disturbance – temporary No significant effect on feature of
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salmon, allis shad, European Mortality - permanent International importance smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey) disturbance/mortality to migratory fish
Migratory fish – (Atlantic Loss – permanent No significant effect on feature of salmon, allis shad, European Damage - temporary International importance smelt, sea trout, European eel, twaite shad, river lamprey, sea lamprey) loss and damage to foraging habitats as a result of increased siltation and pollution
Other fish species (bass, Disturbance – temporary No significant effect on feature of lemon sole, sole, sprat, Mortality - permanent Regional importance monkfish, mackerel, spurdog, whiting) – disturbance/mortality to resident fish species
Other fish species (bass, Loss – permanent No significant effect on feature of lemon sole, sole, sprat, Damage - temporary Regional importance monkfish, mackerel, spurdog, whiting) – loss and damage to foraging habitats as a result of increased siltation and pollution
Marine mammals (bottlenose Temporary No significant effect on feature of dolphin, harbour porpoise and District/Borough importance grey seal) – disturbance from piling and dredging
Operation
Subtidal mudflats associated Temporary No significant effects on feature of with Plymouth Sound and International importance Estuaries SAC – physical damage to habitats as a result of increased siltation
Subtidal mudflats associated Temporary No significant effect on feature of with Plymouth Sound and International importance Estuaries SAC – physical damage to habitats as a result of pollution or toxic contamination
Bird species associated with Temporary No significant effect on features of Tamar Estuaries Complex International and National SPA, Lynher Estuary SSSI, St importance John’s Lake SSSI – disturbance to birds by
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maintenance dredging
Bird species associated with Temporary No significant effect on features of Tamar Estuaries Complex International and National SPA, Lynher Estuary SSSI, St importance John’s Lake SSSI – disturbance to birds by re- fuelling operations
Bird species associated with Temporary No significant effect on this feature Tamar Estuaries Complex of International importance SPA, Lynher Estuary SSSI, St John’s Lake SSSI – physical damage to habitats as a result of increased siltation, pollution or toxic contamination from maintenance dredging
Whitsand and Looe Bay MCZ Temporary No significant effect on feature of – physical damage to habitats National importance. and species as a result of increased siltation
Seagrass beds – loss and Loss – permanent No significant effect on this feature damage of habitat by Damage - temporary of County importance maintenance dredging
Seagrass beds – loss and Loss – permanent No significant effect on this feature damage of habitat by pollution Damage - temporary of County importance
Migratory fish (Atlantic salmon, Temporary No significant effect on this feature allis shad, European smelt, of International importance sea trout, European eel, twaite shad, river lamprey, sea lamprey) – disturbance to migratory fish by maintenance dredging
Migratory fish (Atlantic salmon, Loss – permanent No significant effect on this feature allis shad, European smelt, Damage - temporary of International importance sea trout, European eel, twaite shad, river lamprey, sea lamprey) – loss and damage to foraging habitats as a result of increased siltation and pollution from maintenance dredging
Other fish species (bass, Temporary No significant effect on this feature lemon sole, sole, sprat, of Regional importance monkfish, mackerel, spurdog, whiting) – disturbance to resident fish species by maintenance dredging
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Other fish species (bass, Temporary No significant effect on this feature lemon sole, sole, sprat, of Regional importance monkfish, mackerel, spurdog, whiting) – damage to spawning habitat for resident species as a result of maintenance dredging, pollution and toxic contamination
Marine mammals (bottlenose Temporary No significant effect on these dolphin, harbour porpoise and features of District/Borough grey seal) – disturbance from importance maintenance dredging
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7 ARCHAELOGY AND CULTURAL HERITAGE 7.1 Introduction
This chapter to the ES considers the likely significant effects of the Development upon archaeology and cultural heritage. It describes the assessment methodology; the current baseline conditions within the site and its environs; the significant environmental effects anticipated during the construction, operation and decommissioning phases of the Development; the mitigation measures required to prevent, reduce or offset any significant adverse effects; and the likely residual effects after mitigation. 7.2 Regulatory and Policy Framework
This assessment has been undertaken in accordance with current international and national legislation, and national, regional and local plans and policies relating to archaeology and cultural heritage. A summary of the relevant legislation and policies, the requirements of these policies and the proposed Development response has been provided below.
National legislation, policy and guidance that are relevant to the Development include UK statute, UK planning policy and guidance produced by UK governmental and non-governmental organisations. In addition some maritime legislation, which is not specific to cultural heritage, has an effect upon submerged archaeology. The list of legislation and policy is as follows:
• Ancient Monuments and Archaeological Areas Act (1979); • Protection of Wrecks Act (1973); • National Heritage Act 1983 (amended 2002); • Protection of Military Remains Act (1986); • Merchant Shipping Act (1995); • Town and Country Planning Act (1990); • Planning (Listed Buildings and Conservation Areas) Act (1990); • National Heritage Act 1983 (amended 2002); • National Planning Policy Framework (2012); • PPS5 Practice Guide (2010); • Marine and Coastal Access Act (2009) • UK Marine Policy Statement (2011) • English Heritage publication 2008: ‘Conservation Principles: policies and guidance for the sustainable management of the historic environment’; • English Heritage guidance 2011: ‘The Setting of Heritage Assets: English Heritage Guidance’; • Joint Nautical Archaeology Policy Committee Code for Practice for Seabed Developers. • Cornwall Local Plan (March 2013)
7.2.1 National Planning Policy Framework (NPPF)
In the NPPF (CLG 2012), a ‘heritage asset’ is defined as a building, monument, site, place, area or landscape positively identified as having a degree of significance meriting consideration in planning decisions. Heritage assets are a valued component of the historic environment and include both designated heritage assets and non-designated heritage assets. Designated
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heritage assets include World Heritage Sites, Scheduled Monuments, Listed buildings, Registered Parks and Gardens, Registered Battlefields, and Conservation Areas. Non- designated heritage assets include those identified by the local planning authority during the process of decision-making or through the plan-making process (including local listing). The significance of a heritage asset is defined as the value of a heritage asset to this and future generations because of its heritage interest (see section 7.3.4 below). Policies relate to both the treatment of the assets themselves and their settings, both of which are a material consideration in development management decision making.
The NPPF states that “The purpose of the planning system is to contribute to the achievement of sustainable development” and that there are “three dimensions to sustainable development: economic, social and environmental” . The role the environment will play is described as “contributing to protecting and enhancing our natural, built and historic environment” .
Local planning authorities can request that the applicant should describe “the significance of any heritage assets affected, including any contribution made by their setting” . The level of detail required in the assessment should be “proportionate to the assets’ importance and no more than is sufficient to understand the potential impact of the proposal on their significance” . “Where a site on which development is proposed includes or has the potential to include heritage assets with archaeological interest, local planning authorities should require developers to submit an appropriate desk-based assessment and, where necessary, a field evaluation.”
Local planning authorities should take this assessment into account when considering the impact of a proposed development, “to avoid or minimise conflict between the heritage asset’s conservation and any aspect of the proposal” . A key policy within the NPPF is that “when considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation. The more important the asset, the greater the weight should be.”
“Significance can be harmed or lost through alteration or destruction of the heritage asset or development within its setting. As heritage assets are irreplaceable, any harm or loss should require clear and convincing justification. Substantial harm to or loss of a grade II listed building, park or garden should be exceptional. Substantial harm to or loss of designated heritage assets of the highest significance, notably scheduled monuments, protected wreck sites, battlefields, grade I and II* listed buildings, grade I and II* registered parks and gardens, and World Heritage Sites, should be wholly exceptional.”
However, where a proposed development will lead to “less than substantial harm to the significance of a designated heritage asset” , this harm should be weighed against the public benefits of the proposal. With regard to non-designated heritage assets specific policy is provided in that a balanced judgement will be required having due regard to the scale of any harm or loss and the significance of the heritage asset affected. 7.2.2 Maritime Legislation, Planning Policy and Guidance
Maritime archaeological sites in the UK are not protected unless specific action has been taken to protect them. There are two different acts under which wrecks may be protected: the Protection of Wrecks Act 1973 (PWA 1973), and the Protection of Military Remains Act 1986 (PMRA 1986). Designation of underwater archaeology (including wrecks and submerged prehistoric sites) is also possible under a third act, the Ancient Monuments and Archaeological Areas Act 1979 (AMAA 1979). In addition, there are UK-wide provisions applying generally to
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people who find or take possession of wreck – including wreck of archaeological interest – under the Merchant Shipping Act 1995 (MSA 1995).
The PMRA 1986 and the MSA 1995 are administered UK-wide by the MOD and the MCA respectively. Section Two of the PWA 1973, which deals with dangerous wrecks, is also administered UK-wide by the MCA.
The UK Marine Policy statement has been prepared and adopted for the purposes of section 44 of the Marine and Coastal Access Act (2009). This Policy Statement provides a framework for the preparation of marine plans and decisions affecting the marine environment. The Policy Statement aims to ‘ensure marine resources are used in a sustainable way’. Provision for heritage is made, to ‘ensure a sustainable marine environment which promotes healthy, functioning marine ecosystems and protects marine habitats, species and our heritage assets’. 7.2.3 Local Planning Policy
Local planning policy is set out within the Cornwall Local Plan. The Cornwall Local Plan has been subject to two rounds of consultation since 2011, and currently the pre-submission version of the document produced in March 2013 forms the local planning policy. Within this document Policy 24 is of relevance to the proposed development site.
Policy 24- Historic Environment:
“Development proposals will need to sustain Cornwall’s local distinctiveness and character and protect and enhance Cornwall’s historic environment and assets according to their international, national and local significance through the following measures:
Protect, conserve and enhance the historic environment of designated heritage assets and their settings, including historic landscapes, settlements, Conservation Areas, marine environments, archaeological sites, parks and gardens and historic buildings.
Protect, enhance and promote the outstanding universal value of the world Heritage Site and its setting; supporting the adopted management plan.
Development and management proposals should be informed by proportionate historic environment assessments and evaluations. Where the balance of a decision in favour of development results in the loss of a heritage asset, the Council will seek appropriate and proportionate mitigation by using planning conditions, management agreements and obligations.” 7.3 Methodology 7.3.1 Introduction
The content of this chapter has been guided by the Institute for Archaeologists guidance 2012: Standard and Guidance for historic environment desk-based assessment (Ref 7-1). Additional relevant documents include: The National Planning Practice Guidance on Environmental Impact Assessment issued by Department of Communities and Local Government (DCLG), which provides guidance on the Town and Country Planning (EIA) Regulations 2011; and ‘Environmental Impact Assessment: a Guide to Procedures’ issued by the former Department of
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the Environment, Transport and the Regions (DETR) and the National Assembly for Wales (Ref 7-2)); and ‘The Design Manual for Roads and Bridges, Volume 11, Section 3, Part 2: Cultural Heritage’ (Highways Agency document 208/07), henceforth referred to as Highways Agency (HA) 208/07 (Ref 7-3).
Consultation with Phil Copleston, Historic Environment Planning Advice Officer, indicated that the LPA would have no concerns relating to the historic environment in relation to the proposed Development. 7.3.2 The Study Area
This assessment focuses on the nature and extent of the heritage resource identified within the site and within a study area comprising a minimum 1km buffer around the redline site area. This study area was defined using best practice. The study area was defined in order to better contextualise the identified heritage resource by enabling examination of its wider landscape setting. The baseline data is discussed in Appendix 7-B and a gazetteer of all known and potential heritage assets is provided in Appendix 7-A. All heritage assets have been attributed a unique reference number and their locations are recorded on Drawing 7-1. Both non-designated and designated heritage assets within the study area were assessed in order to discuss the archaeological potential of the proposed development site. A 1km study area for considering the impacts upon settings of designated heritage assets was considered appropriate as the proposed Development would constitute the replacement of an existing feature of the same scale, form and massing, and would be located only a small distance to the north of the current jetty. 7.3.3 Establishing Baseline Conditions
The baseline survey involved the compilation of readily available archaeological and historical information from documentary, cartographic and photographic sources. The major repositories of information consulted were as follows:
UNESCO Sites on the UNESCO list of World Heritage Sites and the Tentative List of Sites for World Heritage status (January 2012) were assessed and included within the Baseline assessment where relevant.
English Heritage Listed Buildings, Scheduled Monuments, Registered of Parks and Gardens of Historic Interest and Registered of Battlefields recorded by English Heritage were searched, and sites within the study area were included within the Baseline assessment.
English Heritage Archives (EHA) Aerial photographs (1940s onwards) and records of archaeological monuments and events were searched and included within the Baseline assessment where relevant.
UK Hydrographic Office (UKHO) Records of wrecks and obstructions and historic charts were searched and used to inform the Baseline assessment
Cornwall Historic Environment Record (HER)
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Known archaeological sites, find-spots and previous archaeological works and published and unpublished documentary sources held by the Cornwall HER were searched and used within the Baseline assessment.
Plymouth Historic Environment Record (HER) Known archaeological sites, find-spots and previous archaeological works and published and unpublished documentary sources held by the Plymouth HER were searched and used within the Baseline assessment.
Cornwall Records Office Historic maps, charts, documents and publications were used to inform the Baseline.
Plymouth Records Office (PRO) Historic maps, charts, documents and publications were used to inform the Baseline.
Plymouth Central Library Published documentary sources held by Plymouth library were used to inform the Baseline
The Cornish Local Studies Library Historic maps, charts and published documentary sources were used to inform the Baseline.
Online sources Online sources, including the National Heritage List website (NHL), Archaeological Data Service (ADS), the BGS Geology of Britain Viewer and Local Plan information from the Cornwall Council website were used within the Baseline assessment.
Marine Geophysical Data Sidescan sonar, Magnetometer, seismic and bathymetric data collected by Aspect Land and Hydrographic Surveys Ltd (November 2014) was analysed by Cotswold Archaeology as part of this assessment.
Where they were mappable, records were included within the assessment GIS, listed in the gazetteer and illustrated in Drawing 7-1. Other data was used qualitatively to inform the assessment.
Chronology The dating of archaeological remains relies on three distinct chronologies, these are as follows:
Absolute (or calendar) dates which are suffixed with BC (before Christ) and are generically known as ‘big BC’. Such dates are part of our present day calendar (i.e. a date of 3,523 BC occurred 5,537 years ago);
Calibrated radiocarbon dates which are either related to our modern calendar as BC dates or presented as BP (before present) dates. BP dates are calculated in years before 1950, and take into account the increased radioactivity background count following the proliferation of nuclear testing after this date. Therefore, a calibrated date of 4,500 BP indicates a point in time 4,564 years before today (i.e. 2,550 BC).
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Uncalibrated radiocarbon dates which are suffixed with bc (generally known as little bc) and are the original radiocarbon determinations based on the half-life of C14 without compensating for changes in the background count.
Archaeological convention dictates that dates that relate to the Lower, Middle and Upper Palaeolithic periods are referred to in terms of years BP, whilst the Mesolithic and later periods are usually quoted in years BC. These conventions are adhered to in this report. 7.3.4 Assessing Effects
Defining the importance/sensitivity of resource The NPPF uses the term ‘significance’ to refer to what it describes as ‘the value of a heritage asset to this and future generations because of its heritage interest’, i.e. the importance of an asset. In order to avoid confusion with normal EIA terminology the term importance has been used within this chapter.
The assessment of importance has been primarily guided by the policies and guidance contained in ‘Conservation Principles’ (Ref 7-4). The importance of a heritage asset (termed ‘place’ within Conservation Principles) is defined with reference to four areas of value:
• Evidential value, derived from “the potential of a place to yield evidence about past human activity” (Ref 7-4 p.28) and primarily associated with physical remains or historic fabric; • Historical value, derived from “the ways in which past people, events and aspects of life can be connected through a place to the present” (Ref 7-4 p.28). This can derive from particular aspects of past ways of life, or association with notable families, persons, events or movements; • Aesthetic value, derived from sensory and intellectual stimulation and including design value, i.e. “aesthetic qualities generated by the conscious design of a building, structure or landscape as a whole” (Ref 7-4p.30). It may include its physical form, and how it lies within its setting. It may be the result of design, or an unplanned outcome of a process of events; and • Communal value, derived from “the meanings of a place for the people who relate to it”. Communal value derives from the meanings that a historic asset has for the people who relate to it, or for whom it figures in their collective experience or memory. It may be commemorative or symbolic, such as meaning for identity or collective memory (Ref 7-4 p.31).
These four values have been discussed, where appropriate, within this assessment and inform Table 7-1 below, which has also been guided by Tables 7-2, 7-3 and 7-4 below. Further relevant guidance on informing judgement of heritage value includes the aims and objectives set out in the South West Archaeological Research Framework, the research for which published online (Ref 7-5). Additionally Tables 5.1, 6.1 and 7.1 of Annexes 5, 6 and 7 respectively of Highways Agency (HA) 208/07 give further guidance on assessing heritage values. NPPF also identifies designated heritage assets of ‘the highest significance’ namely: Scheduled Monuments; Protected Wreck Sites; Registered Battlefields; Grade I and II* Listed buildings; Grade I and II* Registered Parks and Gardens; and World Heritage Sites. Criteria for assessing heritage asset value are set out in Table 7-1 below.
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Table 7-1 Determining the Importance / Sensitivity of Resource
Importance/ sensitivity Description of resource or receptor
World Heritage Sites and heritage assets of acknowledged international importance, or that can contribute significantly to acknowledged international research objectives. Historic landscapes of international sensitivity (designated or not) and extremely well preserved historic landscapes with exceptional coherence, time depth, or other critical factor(s)
Scheduled Monuments and undesignated assets of Schedulable quality and importance, according to the non-statutory criteria for scheduling monuments utilised by the Secretary of State
Heritage assets displaying considerable evidential, historic, aesthetic or communal value as identified by Conservation Principles High Heritage assets or groups of assets that can contribute substantially to acknowledged national research objectives
Historic landscapes exhibiting considerable coherence, time depth or other critical factors and displaying considerable evidential, historic, aesthetic and communal value as identified by Conservation Principles. The landscape may or may not be associated with Scheduled Monuments
Grade I and II* Listed buildings or other Listed buildings that can be shown to have exceptional qualities in their fabric or associations not adequately reflected in their Listing grade, or undesignated structures of clear national importance. Conservation Areas containing very important buildings Heritage assets that are not Scheduled and that do not meet the criteria for Scheduled Monuments according to the non-statutory criteria for scheduling ancient monuments utilised by the Secretary of State
Heritage assets displaying evidential, historic, aesthetic or communal value as identified by Conservation Principles
Heritage assets, or groups of assets or landscapes, that contribute to regional research Medium objectives, particularly those identified in the research framework for the south-west
Historic landscapes exhibiting reasonable coherence, time depth or other critical factors (including degree of preservation) and displaying evidential, historic, aesthetic and communal value as identified by Conservation Principles.
Grade II Listed buildings or historic buildings. Conservation Areas containing important buildings which contribute significantly to their historic character, or historic townscapes with important historic integrity
Heritage assets displaying limited evidential, historic, aesthetic or communal value as identified by Conservation Principles
Low Heritage assets, or groups of assets, that contribute to a limited degree to regional research objectives, particularly those identified in the research framework for the south-west
Historic landscapes exhibiting limited coherence, time depth or other critical factors and
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Importance/ sensitivity Description of resource or receptor
displaying evidential, historic, aesthetic and communal value as identified by Conservation Principles.
Historic landscapes whose sensitivity is limited by poor preservation and/or poor survival of contextual associations. Heritage assets with very little or no surviving archaeological interest, and little or no evidential, historic, aesthetic or communal value as identified by Conservation Principles
Heritage assets or groups of assets that cannot appreciably contribute to acknowledged Negligible regional research objectives
Historic landscapes exhibiting little or no coherence, time depth or other critical factors and displaying evidential, historic, aesthetic and communal value as identified by Conservation Principles
Buildings of no architectural or historical note and buildings of an intrusive character The importance of the resource has not been ascertained. Uncertain Archaeological resources the importance of which cannot be ascertained. Buildings with some hidden (i.e. inaccessible) potential for historical significance.
The magnitude of development change upon heritage assets The classification of the magnitude of change on heritage assets is rigorous and based on consistent criteria. This takes account of such factors as the physical scale and type of disturbance anticipated to affect them and whether features or evidence would be lost that are fundamental to their historic character and integrity. Changes may be adverse or beneficial. Depending on the nature of the change and the duration of development, effects can be temporary and/or reversible or permanent and irreversible. The magnitude of the change is assessed using the criteria in Table 7-2 below. This is based on Tables 5.3, 6.3 and 7.3 of Annexes 5, 6 and 7 respectively of Highways Agency (HA) 208/07, (Ref 7-3).
The descriptions of change describe the ways in which an asset or elements of its setting may be modified or removed by the proposed development, and will include the consideration of such issues as which and how many elements of an asset are affected; whether the change physically modifies the asset or whether it comprises changes in visual aspects, noise or access that would alter its setting; and whether the change in the significance of an asset will be adverse or beneficial.
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Table 7-2 Assessment of the Magnitude of Change
Magnitude Description of Change of Change
Change to most or all key archaeological or historic building elements, such that the asset is totally altered Total changes to setting of archaeological or historic building assets High Change to most or all key historic landscape elements, parcels or components; extreme visual effects; gross change of noise or change to sound quality; fundamental changes to use or access; resulting in total change to the character of a historic landscape area.
Changes to many key archaeological or historic building elements, such that the asset is noticeably modified Changes to setting of archaeological or historic building assets, such that it is noticeably modified Medium Changes to many key historic landscape elements, parcels or components; visual change to many key aspects of the historic landscape; noticeable differences in noise or sound quality; considerable changes to use or access; resulting in moderate changes to the character of a historic landscape area.
Changes to key archaeological or historic building elements, such that the asset is slightly modified Changes to setting of archaeological or historic building assets, such that it is slightly altered and noticeably changed Low Change to few key historic landscape elements, parcels or components; slight visual changes to few key aspects of historic landscape; limited changes to noise levels or sound quality; slight changes to use or access; resulting in limited changes to the character of a historic landscape area.
Very minor changes to archaeological or historic building elements or setting Very minor changes to key historic landscape elements, parcels or components; virtually Negligible unchanged visual effects; very slight changes in noise levels or sound quality; very slight changes to use or access; resulting in very small change to the character of a historic landscape area.
No change to archaeological elements or historic building fabric and setting No Change No change to elements, parcels or components; no visual or audible changes; no changes arising from amenity or community factors
The significance of the effect of development Following the evaluation of the importance of the cultural heritage resource and the magnitude of the change, the significance of the effect after mitigation is assessed using the matrix shown in Table 7-3 below, based on Table 5.1 of Highways Agency (HA) 208/07, (Ref 7-3). Where two alternatives are given in the table, professional judgement is used to decide which best reflects the significance of the effect of the impact identified. The significance of effect may be adverse or beneficial.
Where the importance of the heritage asset is uncertain the Significance of Effect is unknown. The identification of an Unknown significance of effect relates to situations where, based on the historic development and background potential of the site area, there is some limited potential
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for archaeological remains to be present within the site, although detailed surveys of the site in line with industry standards have not provided any direct evidence of such remains. The range of evidence assessed to understand potential within this chapter is in line with industry standards and a proportionate level of assessment has been undertaken to minimize the risks of significant effects going undetected. Thus the remaining potential is considered to be limited, and the risks of encountering such remains minimised through thorough assessment. However where the value of any such potential remains is uncertain, the Significance of Effect is unknown.
Table 7-3 Determination of the Significance of Effect
Importance/Sensitivity of Receptor High Medium Low Negligible Uncertain
Slight to Neutral/ not Unknown High Major Major Moderate significant
Slight to Neutral/ not Unknown Magnitude Medium Major Moderate Moderate significant of Change
Slight to Slight to Neutral/ not Unknown Low Slight Moderate Neutral significant
Neutral/ Unknown Negligibl Neutral/ not Neutral/ not Neutral/ not not e significant significant significant significant
The significance of the judged effect is then discussed, in line with Table 7-4 below, which summarises the ‘qualitative’ effect with reference to key planning policy. Key principles that are considered are whether the change comprises substantial harm or total loss, and whether the asset is of such a value/importance that such a change would be exceptional, or indeed wholly exceptional.
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Table 7-4 Qualitative Description of the Significance of Effect
Significance of Effects
Significance Criteria
Substantial harm or total loss of the value of a designated heritage asset (or Major Adverse asset worthy of designation) such that Development should not be consented unless substantial public benefit is delivered by the Development.
Less than substantial harm or total loss of the value of a designated heritage asset (or asset worthy of designation) such that the harm should be weighed against the public benefit delivered by the Development to determine consent. Moderate Adverse Harm to a non-designated heritage asset, of a greater degree than that perceived of as Slight Adverse, which should be taken into account in determining an application.
Harm to a non-designated heritage asset that can be adequately compensated through the implementation of a programme of industry standard mitigation measures.
Slight Adverse Less than substantial harm to the value of a designated heritage asset, of a lesser degree than that perceived as Moderate Adverse, but which should still be weighed against the public benefit delivered by the Development to determine consent.
Neutral/ Not Effect that is nil, imperceptible and not significant. Significant
Development will deliver a positive contribution and / or better reveal the value Slight Beneficial of a non-designated heritage asset.
Development will deliver a positive contribution and / or better reveal the value Moderate of a designated heritage asset (or asset worthy of designation) such that an Beneficial application should be treated favourably.
Development will deliver a positive contribution and / or better reveal the value Major Beneficial of a heritage asset of recognised international value such that an application should be treated very favourably.
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7.3.5 Consultation
This section provides information of the consultations undertaken to inform the assessment of cultural heritage and archaeology. Advice and information provided by the consultees shaped both the assessment methodology and the scope of the assessment.
In March 2013 the MMO provided a Screening and Scoping Opinion, which included advice regarding the site in relation to archaeology and cultural heritage. This Opinion stated that: The project will not impact upon any designated heritage assets, therefore English Heritage will not play an active role in advising on the heritage impacts. This will be the responsibility of Cornwall Council Historic Environment Service, who should be consulted on these works.
In February 2013 CC provided a Screening Opinion. No consultation response had, at that stage, been received from the Historic Environment section and thus general advice was given, as follows:
The ES should include a comprehensive desk based and walk over survey by an appropriately- qualified archaeological contractor. This will be required of the widest affected development area and include the transport links. Such assessment should include:-
(i) An assessment of impacts on any archaeological and historical assets and their settings, and proposed mitigation and recording proposals where appropriate (a “Written Scheme of Investigation”). Archaeological assessments should be undertaken to the appropriate standards of the Institute for Archaeologists;
(ii) Consideration of any impacts on any nearby Listed Buildings, together with non- designated archaeological sites, landscapes and any monuments in the vicinity which are detailed in the Cornwall And Scilly Historic Environment Record and any nearby Conservation Areas;
(iii) Photomontages should include views with receptors as well as the proposed development accurately scaled in the same view;
(iv) Detailed consideration of impacts associated with groundworks, particularly (but not exclusively) those resulting from the provision of, piling, access tracks;
(v) Assessment should make clear the impacts, both direct and indirect, on the significance of heritage assets that may be affected by this development. These findings should be presented in a Heritage Statement, summarising and quantifying all work undertaken in the assessment. The Statement should also consider cumulative impacts on specific heritage assets, as well as on their settings.
The Cornwall Council Historic Environment Service holds detailed information about designated and undesignated archaeology and should be consulted during the pre-application stages.
In June 2013 Cornwall Historic Environment Record and Plymouth Historic Environment Record was consulted in order to obtain data relating to archaeological sites, monuments, events and finds within the site and study area. This data was provided by the HER. Information on any wider studies, in particular considering the prehistoric remains of the Hamoaze or Tamar, was also sought. Advice given by the Historic Environment Records led to consultation with Plymouth University regarding research in the Hamoaze.
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In June 2013 Plymouth University was consulted in order to discuss research carried out in the Hamoaze area. This consultation resulted in the acknowledgement by Plymouth University of a study carried out within the vicinity of the study area. Correspondence indicated that walkover surveys of the foreshore in this area had been conducted by the University, and had recorded remains, the majority of which are indicated to have been debris although a hulk and potential archaeological site were also recorded away from the site, within Thanckes Lake.
In June 2013 the English Heritage Archives were consulted in order to obtain data relating to archaeological sites, monuments and events within the site and study area. Additionally aerial photographs covering the site were also consulted at this time.
In September 2013 the Historic Environment Planning Advice Officer at CC was consulted about the proposals. The Council had no concerns relating to the historic environment over the proposed Development.
Table 7-5 Consultation responses
Consultee Summary response Measures taken to address this response MMO The project will not impact Consulted with Cornwall Council Historic upon any designated heritage Environment Service assets, therefore English Heritage will not play an active role in advising on the heritage impacts. This will be the responsibility of Cornwall Council Historic Environment Service, who should be consulted on these works
Cornwall No response to scoping None required Council opinion. Response received Historic from Phil Copleston, Historic Environment Environment Planning Advice Service Officer at Cornwall Council, who had no concerns relating to the historic environment over the proposed Development
7.3.6 Limitations and Assumptions
Information from investigations and archaeological remains recorded within the study area and wider vicinity of the site has been interpreted taking into account the surrounding landscape, environment, topography and geology, and has been used to inform the potential of the proposed Development site. This has been done under the assumption that recorded remains are in general representative of the nature and character of further potential remains surviving within adjacent areas.
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7.4 Description of the Baseline Conditions 7.4.1 Introduction
This section provides an overview of the local geological, pedological, topographical and palaeo-environmental conditions, and an overview of the historical and archaeological background of the Study Area and its environs. All archaeological sites discussed in the text are illustrated in Drawing 7-1. Photomontages have been produced for the development and these are discussed in Chapter 9. 7.4.2 Designated Heritage Assets
No World Heritage Sites or sites included on the Tentative List of Future Nominations for World Heritage Sites (January 2012) are situated within the site or the wider study area.
The baseline survey identified a total of thirty-four Listed buildings, comprising one Grade I Listed building, three Grade II* Listed buildings, and twenty-eight Grade II Listed buildings within the study area, and one Grade II* Registered Park and Garden (Anthony Park). The Listed buildings occur primarily in clusters, with 23 of the total associated with Devonport Dockyard, a further seven are situated within Torpoint, with the remaining three occurring separately and comprising the Grade II Listed Pato Point, Pato House and Building 124 (Mixing House). None of these designated heritage assets lie within, or adjacent to the site.
Within the wider area there are also a number of sites protected under the AMAA 1979 (scheduled monuments), those identified within the scoping document comprise three scheduled monuments at Devonport South Yard, all associated with the early construction of the dockyard. A further three scheduled monuments are located at Devonport North Yard, relating to the Bullpoint gunpowder magazines and camber. Additionally a scheduled monument is also located at Torpoint, comprising a ballast pond.
There are no wrecks within the site of the study area that are protected under the PWA 1973 or the PMRA 1986. 7.4.3 Summary of Non-designated Heritage Assets
The range of sites within the study area includes medieval settlements and a small number of wrecks, however most are post-medieval and modern features and relate primarily to the development of Devonport Dockyard and the settlement of Torpoint. All identified non- designated heritage assets are listed in the gazetteer in Appendix 7-A, and their locations are depicted on Drawing 7-1.
Appendix 7-B discusses the identified heritage resource by period, setting identified sites within their wider historical background.
The known and potential cultural heritage resource within the site and study area is discussed in relation to two distinct types of archaeology: Prehistoric archaeology relating to the potential inhabitation of land that is now submerged during periods of lower sea level; and maritime and coastal archaeology relating to seafaring and the use of the inter-tidal area for a wide range of activities.
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The prehistoric archaeology is discussed with reference to what is known about sea level change during the last one million years - the approximate period for which human activity is known for the British Isles. This has been done in order to establish when the study area was dry land, and therefore available for exploitation by humans. Thereafter the geology and palaeo- environment of the area has been assessed in order to determine whether deposits relating to those periods when the area was dry land may potentially survive. This is followed by a discussion of the archaeological evidence for those periods where there is potential for the survival of deposits. This discussion runs from the Lower Palaeolithic period up to the end of the Iron Age, at which time sea level rose to a point close to its current position.
The assessment of baseline data within Appendix 7-B identified very low potential for remains of Palaeolithic, Mesolithic, Neolithic, Bronze Age and Iron Age to be present as submerged remains within the site. There is also considered to be very low potential for terrestrial remains of Roman or early medieval archaeology to be present within or adjacent to the site. A low potential for medieval and post-medieval remains on Yonderberry Peninsula has been identified. Yonderberry peninsula appears to have undergone large scale disturbance and remodelling associated with the construction of the oil depot, and as such any earlier archaeological remains within the terrestrial area are likely to have been removed.
Maritime archaeology within the area is discussed in relation to known wrecks and the potential for further wrecks. The inter-tidal zone has been separated out from the main maritime section due to the potential for non-shipwreck related archaeology.
Geophysical surveys conducted within the site recorded a series of features within this area, which included a small boat associated with a very small anchor, moorings, and debris. The UKHO record other wreck remains within the study area. The potential for further wrecks to be found within the site is considered to be low, although the area off Yonderberry point has been as a mooring from at least the 19th century (Drawing 7-9) and historic maps indicate moorings in the area from the post-medieval period.
7.4.4 Determining the Importance / Sensitivity of Resource
The only records that relate to identifiable sites, finds or objects within or close to the footprint of the development are all geophysical anomalies. Where the features can be identified to type, i.e. anchors, mooring blocks, cables and a small wreck, there is no confirmed date, and therefore they are of Uncertain level of importance. However, the nature of the anomalies, and their location on the surface of the river bed in the area close to the current jetty strongly supports a modern date, therefore the likely level of importance can be amended to Negligible .
Those anomalies identified as debris are of unknown type, and thus are of uncertain importance. However, their general nature and location within an area used for vessel mooring over a long period of time, suggests that they are likely to be associated with that activity and thus their level of importance is likely to be low .
In addition to the known sites and anomalies there is a general low level of potential for the presence of currently unknown wrecks and wreck related material, and a very low potential for the presence of submerged Prehistoric archaeology within the area of the site. The importance of any sites that may be associated with this potential is currently Uncertain. However, in order to remove uncertainty the precautionary principle has been used.
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The potential for remains of submerged prehistory is considered to be very low, and no evidence for such remains has been recorded by borehole surveys across the site. Restricted areas of peat may potentially survive as discreet horizons in between borehole locations, however this is again considered unlikely as the absence of any peat deposits within boreholes indicates that the general area of the site is unlikely to have been conducive for peat formation or survival. However, if discreet areas of submerged prehistoric landscapes were identified within the site, they may have the potential to provide palaeoenvironmental or archaeological data pertaining to the prehistoric period. The remains may have the potential to contribute to Research Aim 23 in the South-West Archaeological Research Framework: Improve our understanding of past climate and sea level changes together with their effects on the peoples relationships with landscapes and the sea (Ref 7-5). Given their restricted potential areas, these remains are unlikely to exceed medium heritage value .
As regards wrecks, the potential for remains of this nature of any period to be present within the site is considered to be very low, and no timbers were recorded by boreholes taken within the site. However silts and sands recorded by boreholes may provide a good preservation environment for remains of wreckage. Thus, while the potential for such remains is very low, if any remains of wrecks were to survive within the site they may be well preserved, could date from the prehistoric period onward, and may encompass remains relating to important events which are known to have taken place within the area, such as Civil War battles. Thus these remains could potentially be of high heritage value . 7.5 Design and Mitigation
Construction Anticipated construction activities with the potential to physically affect any archaeological remains within the Site comprise:
• The insertion of two dredged boxes • The insertion of piles associated with the construction of the jetty and mooring dolphins • The removal of the current jetty and associated mooring dolphins • Vessel anchoring and use of jack-up barges during the construction and use of the jetty • Indirect Impacts
The impact areas are shown on drawing 7-8.
Dredging - As described in Chapter 2,a new berth pockets will be constructed through dredging. The berth pocket, to be situated on the channel side of the new jetty head, would have a minimum maintained depth of -11.6mCD, and an approved dredge depth of -12.2mCD, to enable safe mooring of ships at the jetty at all states of the tide. The new berth pocket will be 300m long by 45m wide.
Additionally an area will also be dredged to the rear (western) side of the new jetty head. This would be to provide a navigational channel to the fuel pontoon, as described in Chapter 2. The navigational channel would be 40m wide, with a minimum maintained depth of -5.0m CD and an approved dredge depth of -5.6m CD.
Capital dredging will be required to create the new berth pocket and navigational channel. It is anticipated that this dredging will be undertaken by TSHD or cutter suction dredger. The
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maximum design dredge depth is -12.6mCD and -5.6m CD for the areas respectively. A new Marine Licence will be required for the capital dredging proposed to accommodate the construction of the new berth pocket and navigational channel. The estimated volume of sediment arising from the dredging is estimated to be approximately 37,000m 3 (subject to final design calculations). Drawing 2-7 shows the extent of the proposed relocated berth pocket. Impacts associated with this element of the construction would be restricted to the initial dredging activities, with maintenance dredging posing no threat to potential archaeological remains as it would remove only fill of the dredged box.
Material to be dredged is understood to be predominantly silt. Piles to be inserted as part of the proposed development would be associated with the construction of the approach jetty, jetty head, mooring pontoon, vessel protection barrier and mooring dolphins. It is likely that the approach jetty will be constructed on piles in the order of 900mm and that the jetty head will be constructed on tubular piles of 900mm to 1200mm diameter. The mooring pontoon and vessel protection barrier will involve smaller piles (likely to be 600mm diameter). Note that all dimensions quoted are approximate and may be subject to change at detailed design stage.
Construction plans indicate that the piles would extend through all deposits into the bedrock, as such any archaeological remains situated within the footprint of the piles would be impacted. However, the insertion of piles would not result in the complete removal of archaeological deposits, but rather would result in localised areas of impact associated with the footprint of the pile with a surrounding impact zone, which would be dependent on the piling technique used.
Removal of the current jetty and mooring dolphins to the south of the proposed development is likely to cause limited disturbance of the seabed. However, any disturbance is likely to be in areas which have already been impacted by insertion of the piles during the construction of the current jetty.
Vessel anchoring and the use of jack-up barges during the construction of the jetty is likely to cause some limited disturbance to the seabed in the areas around the proposed jetty. This impact will be limited to the surface and top c. 0.5m of the modern seabed sediments.
Impacts of construction have the potential to affect heritage assets through alterations to their setting. However, as the proposed development would constitute the replacement of an existing feature of the same scale, form and massing, and would be located only a small distance to the north of the current jetty, impacts affecting the setting of heritage assets are not anticipated.
A site compound will be established within the current Thanckes OFD for use by the Contractor and the Client’s Representative administration and welfare facilities, on an area of land between Tank 6 & the Tank row 15 – 18. In addition a working area will be established for materials storage and construction of all land based elements and for installation of infrastructure on the jetty deck. This will be located in the existing crew car park area, adjacent to the new Yonderberry Jetty root. These elements of the Development are not expected to be associated with below ground impacts, and will be located in the area where extensive previous impacts, associated with the construction of the depot have occurred. It is anticipated that the jetty services will be connected to the pre-existing services in use with the current jetty, with no new impacts.
Operation Anticipated operational activities with the potential to physically affect any archaeological remains within the Site relates to anchoring of vessels around the jetty.
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Anchoring associated with vessels during the use of the jetty is likely to cause some limited disturbance to the seabed in the areas around the proposed jetty, and may cause disturbance to any archaeological remains however this disturbance is likely to be localised and restricted to the top 0.5m of the modern seabed sediments.
Decommissioning of the jetty and its removal Decommissioning and removal of the proposed jetty and associated features is likely to be associated with limited disturbance of the seabed during removal of piles. However, any disturbance is likely to be in areas which have already been impacted upon by the original construction phase. 7.6 Assessment of Effects 7.6.1 Magnitude of Development Change
Within the dredged boxes the magnitude of development change will be High for any archaeology that survives within the sediments to be removed. The impact will also be high for any archaeology within the footprint of the piling, though this will be restricted to a small percentage of any site, and thus the magnitude of development change will be Low-Medium .
Where the impact will arise from vessel anchoring and the use of jack-up barges the impact will be restricted to a small footprint and with a low level of damage, thus the magnitude of development change will be Negligible-Low.
During decommissioning impacts are likely to be similar to those described for construction, and related to impacts associated with anchoring of vessels and jack-up legs for barges. The Magnitude of Development Change in these areas is Negligible-Low. 7.6.2 Assessment of Significance of Effect
Construction Heritage assets within or close to the site comprise those identified by the geophysical survey. These remains lie principally within the area of impact associated with the anchoring of vessels during the construction of the jetty.
The level of Importance/Sensitivity attached to these sites varies from Negligible to Low , with some degree of Uncertainty in some cases. The Magnitude of Development Change in areas which would undergo impacts associated with anchoring vessels is Negligible-Low . Therefore the Significance of the effect of the development upon the known archaeology is at worst Slight in these areas.
Within the area proposed for dredging associated with the new navigational channel there are four geophysical anomalies (Drawing 7.1: 63, 65, 66, 68 ). These anomalies have been interpreted as a cable, two possible cables and a mooring. All are likely to be modern in date, and have a negligible heritage value.
Three anomalies are recorded within the proposed dredge box for the new berth pocket, with one of these lying on the edge of the dredge box adjacent to an area of proposed piling. The latter comprises a piece of debris (Drawing 7.1, 54 ) with a further piece of debris located within
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the area of the proposed dredge box (Drawing 7.1, 73) . Additionally a side scan anomaly interpreted as a small wooden vessel (a rowing boat/tender measuring 2.7m x 1m x 0.5m.) lying next to a very small anchor, (Drawing 7.1, 53 ) and a magnetic anomaly thought to be associated with the charted mooring buoy or it’s tackle (Drawing 7.1, 67 ) also lie within the dredge box. The magnitude of change within the proposed dredge boxes would be high. For those remains of negligible value, principally within the area of the proposed dredge box for the navigational channel, a high magnitude of change upon the remains, of negligible value, would result in an effect which is neutral or not significant.
As the pieces of debris (Drawing 7.1, 54, 73 ) lie within the dredge box and adjacent to an area of proposed piling, both of which can reach up to a High Magnitude of change, the assessment is based upon the maximum magnitude of change for these areas; high. An impact of High Magnitude upon the debris of low value would result in a Slight to Moderate Significance of effect. In instances where the significance of effect has two possible ratings professional judgement must be used to determine between these. On balance, taking into account the location of the debris on the surface of the river bed and its position adjacent to the current pier, this would suggest that the remains are unlikely to be of archaeological interest. Thus its removal would not be anticipated to constitute more than a Slight Significance of effect.
The likely remains of the small vessel and mooring buoy are considered to be of Negligible Importance/ Sensitivity. Lying within the dredge box they would likely undergo impacts anticipated to represent a High Magnitude of change, which would result in a Significance of effect of Neutral/ Not significant .
There is low potential for as yet unrecorded shipwreck archaeology or submerged prehistoric remains to be present within the site, the value of which is Uncertain. However, although the potential is low, the precautionary principle has been used. Remains of submerged prehistory would not be anticipated to exceed medium heritage value , while remains of wrecks within the site could potentially be of high heritage value . The likelihood of either remains occurring is considered to be very low. Such potential remains could incur impact of up to a high magnitude of change , if encountered within the areas of proposed dredging. This would result in, at most, a Major Significance of Effect . Although this significance of effect has been identified in relation to remains which have a very low potential of occurring within the proposed development site, mitigation would be necessary and is outlined below.
The proposed Development would constitute the replacement of an existing feature of the same scale, form and massing, and would be located only a small distance to the north of the current jetty, therefore no impacts on designated heritage assets through changes to their settings is anticipated.
Operation As for construction, the majority of heritage assets of assessable importance within or close to the site lie within the area of impact associated with the anchoring of vessels during use of the jetty. The level of Importance/Sensitivity attached to these sites varies from Negligible to Low, with some degree of Uncertainty in some cases. The Magnitude of Development Change in these areas is Negligible-Low. Therefore the Significance of the effect of the development upon the known archaeology is at worst Slight .
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Decommissioning Decommissioning activities are unlikely to result in significant additional disturbance to the sea bed (as the jetty is likely to be removed by cutting the supporting structures off just below bed level. Impacts are therefore likely to be similar to those described for construction above (related to impacts associated with anchoring of vessels and jack-up legs for barges). The Magnitude of Development Change in these areas is Negligible-Low. Therefore the Significance of the effect of the development upon the known archaeology is at worst Slight. 7.6.3 Cumulative Effects
Other Proposed Developments Geophysical anomalies within the site footprint would not be anticipated to undergo any cumulative impacts associated with the construction of other proposed developments as described in chapter 3.6. As no other impacts to heritage assets within the site or study area have been identified, no cumulative effects on archaeology and cultural heritage are anticipated. 7.6.4 Additional Mitigation
The significance of effect for the known archaeology is slight, therefore no mitigation is considered to be warranted.
Action would be required at the construction phase in order to mitigate impacts upon potential archaeological remains within the site. An archaeological watching brief, involving archaeological attendance during dredging, would constitute an appropriate mitigation strategy for dealing with the potentially Major Significance of Effect identified with regard to low potential archaeological remains within the site area using the precautionary principle. During the initial stages of the dredging programme an assessment would be made, on the basis of the nature and inclusions within the material dredged, as to whether the continued presence of an archaeologist would be required on site, or whether dredger staff could continue to monitor operations. It would be necessary to report any finds made during the monitoring process using an appropriate finds reporting protocol. The reporting protocol will be implemented by the dredging contractor with archaeological support if necessary in the form of ad hoc advice regarding any significant finds recovered. This will satisfy the requirements of the Merchant Shipping Act 1995 as well as archaeological objectives. This would render the significance of effect slight . 7.7 Summary
No designated heritage assets lie within the proposed development site. The only non- designated heritage assets are geophysical anomalies, most of which are modern in date or undated debris.
There is a very low potential for the presence of submerged prehistoric archaeology, and for the presence of currently unknown pre-medieval watercraft. In addition there is a low potential for remains of wreckage relating to vessels moored or sunk within the site during the post-medieval and modern periods. Any such remains are not likely to be substantial or complete and their importance is uncertain. An archaeological watching brief would be an appropriate mitigation strategy to address potential archaeological remains within the site.
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As the proposed Development would constitute the replacement of an existing feature of the same scale, form and massing, and would be located only a small distance to the north of the current jetty, no impacts on designated heritage assets, through changes to their settings, is anticipated.
No cumulative impacts upon archaeology or cultural heritage are anticipated in association with the proposed Development.
Table 7-6 Archaeology and Cultural Heritage Impact Summary Table Impact description Temporary/Perm Proposed Significa Significant anent Mitigation nce Effect Measures rating
Impact of vessel Permanent None Slight anchoring during construction and operation
Impacts of dredging Permanent None Neutral upon small vessel
Impacts of dredging Permanent None Neutral upon mooring buoy
Impacts of dredging Permanent None Slight upon debris
Impacts of dredging Permanent None Neutral upon cables and possible cables
Impact of dredging Permanent Archaeological High/ Slight, upon potential watching brief and Medium following archaeology finds reporting mitigation protocol during dredging operations
Impact of piling upon Permanent None Unknown potential archaeology
Impact of vessel Permanent None Unknown anchoring upon potential archaeology
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8 NOISE AND VIBRATION 8.1 Introduction
The purpose of the noise and vibration assessment is to identify and assess the noise and vibration impacts associated with the Development. Noise and vibration impacts will be considered during the construction and operation of the Development and associated plant. 8.2 Regulatory and Policy Framework
This impact assessment has been undertaken in accordance with current national legislation, and national and relevant policies and guidance relating to noise and vibration in the context of the proposed Development. A summary of the relevant legislation and policies, the requirements of these policies and the proposed Development response has been provided in Table 8-1 below.
Table 8-10 Regulatory and Policy Framework
Policy/Legislation Summary of Requirements Development Response
Noise Policy Statement The Noise Policy Statement for None. NPSE provides an overarching for England England (published on 15 March policy framework that has been (NPSE) 2010) sets out the long term embraced in assessing noise impacts. vision of Government noise policy, which is to promote good health and a good quality of life through the management of noise within the context of Government policy on sustainable development. National Planning None. NPPF provides an overarching National Planning Policy Policy Framework. (July policy framework that has been 2012) Framework (NPPF) formally embraced in assessing noise impacts. published on 27 March 2012.
Environment Protection Once the development is None, for reference indicating the Act 1990 completed, noise and vibration importance of good acoustic design. The arising can be considered in assessment has considered BS4142 terms of statutory nuisance. Part when assessing operational noise 3 of the Environmental impacts. Protection Act 1990, as amended by the Noise and Statutory Nuisance Act 1993 (Ref 8-1), contains the main legislation on statutory nuisance and enables local authorities and individuals to take action to secure the abatement of a statutory nuisance.
Control of Pollution Act The Control of Pollution Act Will be relevant should the authorities
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Policy/Legislation Summary of Requirements Development Response 1974 1974 Section 61 sets out advise that a Section 61 Consent procedures for those Application is required. undertaking works to obtain ‘Prior Consent’ for construction works within agreed noise limits.
The Noise Insulation Regulation 5 provides relevant No relevance at this stage of the Regulations 1975 (as authorities with discretionary assessment. amended 1988) powers to provide noise insulation at dwellings to reduce the impact of construction noise
BS5228:1 2009 BS 5228 gives Assessment carried out in accordance +A1:2014 Code of recommendations for basic with BS5228 practice for noise and methods of noise control relating vibration control on to construction and open sites construction and open where work activities/operations sites. Noise generate significant noise levels, including industry-specific guidance.
BS 6472-1:2008: Guide BS 6472 provides guidance on None. Distance separation between to Evaluation of Human predicting human response to construction works and receptor Exposure to Vibration in vibration in buildings. Frequency locations means that vibration impacts Buildings weighting curves for human are unlikely. beings exposed to whole-body vibration are included, together with advice on measurement methods to be employed.
BS8223: 2014: Sound BS8223 gives recommendations Internal noise levels for living rooms and insulation and noise for the control of noise in and bedrooms set out in BS8233 have been reduction for buildings –. around buildings, and suggests considered. Code of practice appropriate criteria and limits for different situations. These criteria and limits are primarily intended to guide the design of new or refurbished buildings undergoing a change of use
8.3 Methodology 8.3.1 Introduction
This impact assessment has been undertaken in accordance with the following and guidance relating to noise and vibration.
° Environmental Protection Act 1990 (Ref 8-2)
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° The National Planning Policy Framework (NPPF) (Ref 8-3) ° BS 4142:1997 ‘Method for rating of industrial noise affecting mixed residential and industrial areas’ (Ref 8-4) ° BS 8233: 2014 ‘Noise insulation and noise reduction for buildings – Code of practice’ (Ref 8-5) ° BS5228:1 2009 +A1 2014 Code of practice for noise and vibration control on construction and open sites. Part 1 - Noise (Ref 8-6) 8.3.2 The Study Area
The Thanckes OFD lies on the west bank of the Hamoaze opposite the north yard of the HMNB, Devonport. The Hamoaze forms part of the Tamar Estuary which lies on the border between Devon and Cornwall.
The noise assessment has considered the closest residential receptor locations to the proposed works. Noise sensitive receptors such as residential receptors that have a clear line of site to the proposed refuelling jetty have been identified. Receptors within approximately 800m of the jetty and construction area have been considered. 8.3.3 Establishing Baseline Conditions
A full noise survey was undertaken at representative residential receptor locations near the Site. Noise monitoring locations and the duration of monitoring was agreed with John Butterwick, Environmental Protection Officer for CC.
It was agreed that noise measurements will be taken to reflect noise levels on a typical weekday. The L Aeq,T ; L A90 ; L A10 ; L Amin and L Amax were measured at all locations. The measurement locations for the whole site are indicated in Drawing 8-1.
An attended noise survey has been conducted at four locations, namely NM1, NM2, NM4 and NM5. The measurements were carried out for 2 hours during the day and 1 hour for night time period.
At NM3 unattended measurements were undertaken for a 24 hour period. Surveys were carried out between 25 and 27 June 2013. 8.3.4 Assessing Effects
The significance of impacts is then determined using the approach described in Chapter 3 of this ES.
Operational Plant Noise Impacts British Standard BS 4142:1997 is used to determine the impacts of noise upon residential units. The guidance provided within BS 4142 provides a method whereby the likelihood of complaints due to noise from industrial sources can be assessed.
The standard advises that the existing background noise levels outside noise sensitive premises are compared with the rating noise levels from any nearby industrial activities. The rating noise
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level should include corrections for any acoustic character to the noise that makes it more readily discernible to a listener (e.g. whines, crashes, bangs etc.).
The background noise level (L A90 ) is the noise level that is exceeded for 90% of the monitoring period at the assessment location. For BS 4142 it is usual to measure the background noise level at the nearest noise sensitive receptor to the industrial noise source.
The specific noise level is the L Aeq produced by the noise source under investigation, measured as close as possible to the source, over a given reference time interval.
The rating noise level is the specific noise level plus any adjustments for the acoustic characteristics of the noise as specified in clause 8.2 of BS4142.
An adjustment of +5dB is applied when the specific noise has a discrete distinguishable tone or distinct impulsive characteristic.
The greater the difference between rating level and background noise level, the greater the likelihood of complaints.
° A difference of around +10 dB or more indicates that complaints are likely.
° A difference of around + 5 dB is of marginal significance.
If the rating level is more than 10 dB below the measured background noise level then this is a positive indication that complaints are unlikely.
It is also recommended that BS4142 is considered in conjunction with other methods of assessment, such as BS8233.
BS8233 sets out noise level targets for spaces within buildings. BS8233 also includes information on sound insulation within buildings and sound insulation properties of building materials and forms of construction.
The criteria in BS 8233 relevant to residential units are presented in Table 8-2.
Table 8-11 Recommended indoor ambient noise levels BS 8233: 2014
Activity Location 07:00 to 23:00 23:00 to 07:00
Resting Living room 35dB L Aeq,(16hour) -
Dining Dining room 40dB L Aeq,(16hour) - /area
Sleeping Bedroom 35dB L Aeq,(16hour) 30dB L Aeq,(8hour) (Daytime resting)
Construction Noise Impacts Construction noise impacts have been assessed in accordance with BS 5228: 2009. BS 5228-1: 2009 +A1:2014 gives recommendations for basic methods of noise control relating to construction and open sites. It applies to work activities and operations that generate significant
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noise levels. It also includes industry-specific guidance. BS 5228-2: 2009 deals with vibration control on construction and open sites. BS5228 also provides guidance concerning methods of predicting and measuring noise and assessing its impact on those exposed to it.
The noise levels were predicted with distance from source by using the measured. L Aeq 1hr using the following formula as described in BS5228: Kh = 20 * log10 (R/10) Where: ° Kh = the correction for propagation across hard ground ° R = the distance to the receptor location ° 10 = the distance in m at which the SPL from the plant has been measured. There are no legislative criteria for limiting noise levels from construction sites. Traditionally , it was stipulated that noise levels outside the nearest window of the occupied room closest to the site boundary between 07.00 and 19.00, should not exceed 70 dB(A) in rural, suburban and urban areas away from main road traffic and industrial noise; and 75 dB(A) in urban areas near main roads in heavy industrial areas.
BS 5228-1, Annex E, sets out criteria for significance based upon noise change. The ABC method describes a threshold of significant effect at dwellings when the total noise level, rounded to the nearest decibel, exceeds a listed category value. If the total noise level (construction plus ambient pre-construction) exceeds the appropriate category value, then a significant effect is deemed to occur.
The criteria to consider for the ABC Method are set out in Table 8-3.
Table 8-12 Example of Threshold of Significant Effect at Dwellings (Table E1 in BS5228)
Threshold value, in decibels (dB) Assessment category and threshold value period
(L Aeq ) Category A Category B Category C (A) (B) (C)
Night-time (23.00−07.00) 45 50 55
Evenings and weekends (D) 55 60 65
Daytime (07.00−19.00) and Saturdays (07.00−13.00) 65 70 75
NOTE 1: A significant effect has been deemed to occur if the total L Aeq noise level, including construction, exceeds the threshold level for the Category appropriate to the ambient noise level.
NOTE 2 If the ambient noise level exceeds the threshold values given in the table (i.e. the ambient
noise level is higher than the above values), then a significant effect is deemed to occur if the total L Aeq noise level for the period increases by more than 3 dB due to construction activity.
NOTE 3 Applied to residential receptors only.
(A) Category A: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are less than these values
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(B) Category B: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are the same as category A values
(C) Category C: threshold values to use when ambient noise levels (when rounded to the nearest 5 dB) are higher than category A values
(D) 19.00–23.00 weekdays, 13.00–23.00 Saturdays and 07.00–23.00 Sundays.
The significance criteria used in the assessment are based on the significance criteria set out in BS5228 and on the significance criteria set out in Chapter 3 Section 7 Noise impacts have been assessed at residential receptor location and therefore in accordance with Table 8-5, would have high sensitivity.
Based on the above criteria and the relatively quiet nature of the area, the following criteria are proposed for assessing construction noise impacts (Table 8-4).
Table 8-13 Criteria for the rating of noise impacts during construction
Magnitude of Impact Noise Level dB L Aeq
Daytime noise levels at houses in excess of 70 dB L Aeq (12 hour) Saturday (afternoon), Sunday and weekday evening noise levels at houses Major in excess of 65 dB L Aeq (1 hour)
Night-time noise levels at houses in excess of 60 dB L Aeq (1 hour)
Daytime noise levels at houses in the range between 65 to 70 dB L Aeq (12 hour) Moderate Saturday (afternoon), Sunday and weekday evening noise levels at houses
in excess of 60 dB L Aeq (1 hour)
Night-time noise levels at houses in excess of 55 dB L Aeq (1 hour)
Daytime noise levels at houses in the range between 55 to 65 dB L Aeq (12 hour) Minor Saturday (afternoon), Sunday and weekday evening noise levels at houses
in excess of 55 dB L Aeq (1 hour)
Night-time noise levels at houses in excess of 45 dB L Aeq (1 hour)
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Defining the importance/sensitivity of resource The importance or sensitivity of each resource is assessed using the criteria provided in Table 8-5.
Table 8-14 Determining the Importance / Sensitivity of Resource
Importance/sensitivity of Criteria resource or receptor
Very High Ambient noise level is intrinsic for community noise levels, health and amenities, e.g. rural dwellings, hospitals, cultural heritage sites, existing ambient level is low.
High Dwellings and other sensitive receptors located in urban areas
Medium Offices and Cultural Heritage sites located in urban areas
Low Commercial establishments such as large shopping complexes
Negligible Factories and industrial process sites
Source: Based on Technical Advice Note: Assessment of Noise (Scottish Government)
The significance of noise impacts, considering the magnitude of impact and sensitivity of receptor, is indicated below (Table 8.6). The significance is based on the magnitude of impact (Table 8-4) and the sensitivity of resource (Table 8-5).
Table 8-15 Significance of Noise Impact
Importance/sensitivity of resource or receptor
Magnitude of Very High High Medium Low Negligible impact
Very Large Large or Very Moderate or Slight or Slight Major Large Large Moderate
Large or Very Moderate or Moderate Slight Neutral or Moderate Large Large Slight
Moderate or Slight or Slight Neutral or Neutral or Minor Large Moderate Slight Slight
Slight Slight Neutral or Neutral or Neutral Negligible Slight Slight
No Change Neutral Neutral Neutral Neutral Neutral
Noise impacts between 70dB(A) and 75 dB(A) would be deemed ‘Large’, while noise impacts above 75 dB(A) would be deemed ‘Very Large’.
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8.3.5 Consultation
Noise monitoring locations and the duration of monitoring was agreed with John Butterwick, Environmental Protection Officer for Cornwall Council. Consultation was carried out by telephone and by e-mail, with final confirmation of noise monitoring locations received by e-mail on 24 June 2013.
Table 8-16 Consultation responses
Consultee Summary response Measures taken to address this response Cornwall Discussed existing noise Noise surveys carried out at agreed locations Council climate in area of Development (locations listed in Table 8-8) Environmental and existing noise sources Health Officer Reviewed possible noise- sensitive areas Agreed noise monitoring locations and
The noise monitoring locations were selected to represent the closest noise sensitive receptor locations. The distance between noise monitoring location and site boundary indicated in table 8-8 represents the distance to the closest point at which dredging and piling has been indicated. The agreed noise monitoring locations are as follows:
Table 8-8 Noise monitoring location and sensitive receptor locations
Distance from Site Boundary Receptors (m)
NM1 Behind 47 Thanckes Drive 740
NM2 Behind 2 Albion Road 490
Yonderberry Cottages (near Wilcove 876 NM3 Inn)
NM4 12 Cove Meadow 860
NM5 2 Pato Point 510
8.3.6 Limitations
The assessment considers construction noise impacts based on information available at this time. Construction method and plant to be used may change and this may alter predicted noise levels.
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8.4 Description of the Baseline Conditions
A full noise survey was undertaken at representative residential receptor locations near the Site between 25 and 27 June 2013. Noise monitoring locations and the duration of monitoring was agreed with John Butterwick, Environmental Protection Officer for CC.
It was agreed that noise measurements will be taken to reflect noise levels on a typical weekday. The L Aeq,T ; L A90 ; L A10 ; L Amin and L Amax were measured at all locations. The measurement locations for the whole site are indicated in Drawing 8-1.
An attended noise survey has been conducted at four locations, namely NM1, NM2, NM4 and NM5. The noise monitoring locations represent the closest residential receptor locations. The measurements were carried out for 2 hours during the day and 1 hour for night time period. At NM3 unattended measurements were undertaken for a 24 hour period.
All measurements were taken using Type 1 sound level analysers complying with BS EN 61672-1 & 2 (2013). The survey was carried out using the following sound level analysers:
Cirrus CR: 831 B Serial Number C19935FF
Rion NL 32 Serial Number 00451268
Various statistical acoustic parameters were recorded at each monitoring location, these included; L Aeq , L AMAX , L AMIN , L A1 , L A10 , L A50 , L A90 and L A99 . The full set of noise survey data is included in Appendix 8-A. The noise survey data is summarised in Table 8-9.
Table 8-9 Summary of Baseline Noise Survey Data
LA90
Location Period LAeq,T Average Minimum Maximum LAmax LAmin
NM1 Day 43.3 39.4 35.7 42.0 66.3 38.4
Night 36.6 31.5 26.9 34.5 63.7 26.0
NM2 Day 53.6 38.4 35.1 41.0 85.5 33.9
Night 35.5 34.3 33.6 35.3 57.7 32.5
NM3 Day 45.0 35.0 23.9 43.6 77.6 21.6
Night 40.8 35.4 23.5 40.6 70.7 22.2
NM4 Day 47.2 42.8 40.0 45.4 66.3 38.4
Night 36.6 35.1 33.2 37.6 50.7 31.7
NM5 Day 46.9 41.1 39.3 44.5 69.3 34.8
Night 33.2 29.8 24.4 33.2 50.6 22.8
NM1 is located at the back of the houses on Thanckes Drive and is screened from road traffic. The monitoring location faces onto the harbour and harbour activities are audible at this location. Daytime and night-time noise levels are generally low at this location.
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Monitoring location NM2 is on a cul-de-sac leading off Albion Road in Torpoint. This location experiences some noise from traffic movements on Albion Road. Activities at the harbour are also audible at this location. The noise data recorded at this location indicate that at night noise levels are much lower than daytime due to low levels of road .traffic on Albion Road.
Measurement location NM3 is located behind Yonderberry Cottages, next to the Wilcove Inn. Occasional local traffic movements generate noise at this location. At time traffic noise from the A74 is also audible at this location.
Measurement location NM4 is located at 12 Cove Meadow. Local use of yachts and other craft as well as harbour activities are sometimes audible at this location.
Measurement location NM5 is located at 2 Pato Point. Harbour activities are audible at this location.
Noise levels recorded at NM3, NM4 and NM5 are low, particularly at night. Night-time noise generated from the operation of any plant on site or from any night-time construction activities will be noticeable.
The measured ambient noise levels indicate that Category A in Table 8-3 would be applicable to residential receptors locations, indicating that the suggested construction noise limits in Table 8- 4 are appropriate to these locations. 8.5 Design and Mitigation
Prior to construction a CEMP will be prepared that will incorporate environmental mitigation measures and procedures. 8.5.1 Construction
Reduction in construction and deconstruction (jetty removal) noise impacts is possible through the adoption of Best Practicable Means (BPM), as outlined in Section 72 of the Control of Pollution Act (1974) (Ref 8-7).
The mitigation measures to be implemented would be selected to suit the specific circumstances at each construction area, considering the nature of the works, the plant to be used and the distance and position of the receptor locations in relation to the works. Fixed plant would for example be easier to screen, while screening would not be practical for mobile plant.
Screening of plant such as piling rigs placed on barges may also not be practicable.
The effectiveness of the screening would depend on the properties of the screening material, the location of the acoustic screen in relation to the source, the height of the acoustic screen and the height of the receptor in relation to the noise source. As a rule of thumb, when there is no clear line of sight between noise source and receptor, a 10dB reduction in noise level can be expected.
° Recommendations and good practice as shown in British Standard (BS) 5228: 2009 +A1: 2014 would be adopted. The typical mitigation measures would include:
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° Careful selection of plant, construction methods and programming. Only plant conforming with relevant national or international standards, directives and recommendations on noise and vibration emissions would be used; ° Static and semi-static plant/equipment would be fitted with suitable enclosures where practicable; ° Personnel would be instructed on BPM to reduce noise and vibration as part of their induction training and as required prior to specific work activities; ° When plant is not being used, it would be shut down and not left to idle; ° Local residents would be consulted in advance of the works commencing; ° Localised mobile screening would be used where reasonably practicable to reduce the noise levels. Use of screening on barges and dredgers may prove impractical. More specific mitigation can be recommended once a detailed construction method statement and inventory of plant is available. Similar mitigation measures would be applied during decommissioning as it is expected similar plant will be used. 8.5.2 Operation
Detailed design information and noise levels for plant to be installed at the loading facility has yet to be finalised, however it is expected that the jetty will operate in the same way as the existing Yonderberry jetty, with similar plant and noise sources. Modern replacement equipment is likely to be quieter in operation. At detailed design stage the exact location of various items of plant and the plant type will be decided and more accurate noise predictions will be possible.
In the absence of detailed design information, the assessment has considered current background noise levels at receptor locations and suggested noise limits for plant that will need to be met at detailed design stage.
Based on predictions in Section 8.6.2, a limit of 80dB for the combined noise from all plant on site has been recommended. This would be in line with the Lower Exposure Limit in the Control of Noise at Work Regulations. This would indicate a noise rating level (L Ar,Tr ) of 35dB at the closest receptor locations at Pato Point and Albion Yard respectively .
Noise from plant to be installed on site can be reduced through enclosing plant where possible. It is proposed that the fire pumps on the jetty are submersible pumps, which will mitigate noise generation.
Pumps will be correctly installed and maintained to ensure proper running and avoid generating unnecessary noise.
Low noise equipment has been considered in the initial design of the site.
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8.6 Assessment of Effects 8.6.1 Construction
Construction noise impacts have been assessed using the construction detail available at this stage. Assumptions have been made regarding the plant to be used during construction based on our experience from similar developments.
The noise emissions from assumed plant have been predicted using the sound pressure levels as described in BS 5228: Part 1. The sound pressure levels (Lp) in BS 5228 have been presented as a L Aeq at a distance of 10 m (Table 8-B1 in Appendix 8-B). It has been assumed that plant would be operating for long periods of time (“percentage on-time”) so as to present a possible worst case.
It is proposed that a hybrid piling rig may be used, combining a steel tube hammer rig with a rotary bored piling rig. Details of the exact rig to be used are not available at this stage. It has been indicated that the pile casings will be pressed through the sediments until firm ground is encountered. The use of vibrating hammer may also be required. When hard bedrock is encountered there may be a need to use limited hammer piling, but the majority of the depth will be achieved through drilling and oscillating the steel casing into the bedrock.
The hammer piling is likely to produce higher noise levels than the rotary bored or vibro-piling. The exact extent or duration of hammer piling is however not known at this stage. A worst case has therefore been presented in this assessment by considering noise levels for a hammer piling rig. Piling works will be confined to daytime hours.
Typical combined impacts associated with the key construction activities are indicated in Table 8-B2 in Appendix 8-B. The predictions are based on typical plant required for each construction activity, and assume that all the plant would run simultaneously, which is most unlikely.
Works on the new jetty head, the approach jetty and mooring dolphins may be undertaken concurrently. The combined noise levels for these activities present the highest noise impact.
The highest predicted weekday daytime construction noise impact has been compared against the magnitude of impact criteria set out in Table 8-4 and the significance criteria in Table 8-5. The results are presented below (Table 8-10).
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Table 8-10 Significance of Predicted Weekday Daytime Construction Noise Impacts
Highest Significance of Sensitive Receptor Predicted Noise Magnitude of Impact Impact (L Aeq,T ) dB
Slight or NM1 Behind 47 Thanckes Drive 55.6 Minor Adverse Moderate Adverse
Slight or NM2 Behind 2 Albion Road 59.2 Minor Adverse Moderate Adverse
Slight or Yonderberry Cottages (near NM3 54.2 Minor Adverse Moderate Wilcove Inn) Adverse
Slight or NM4 12 Cove Meadow 54.3 Minor Adverse Moderate Adverse
Slight or NM5 2 Pato Point 58.9 Minor Adverse Moderate Adverse
Daytime construction noise impacts are generally in the range of 50dB to below 65dB and are therefore considered to be Minor Adverse . The receptor sensitivity is considered to be High and the significance of the daytime construction noise impact is considered to be Slight or Moderate .
Construction works, particularly piling works, are planned to take place during normal work hours. Where there is any particular need to work outside normal hours (0800-1800 on a weekday and 0800 – 1300 on a Saturday), prior agreement will be obtained from the local Environmental Health Officer (EHO). The need for any works outside of normal hours will be established once a contractor has been appointed and the work methods have been defined.
Dredging works will be required and it is expected that dredging will take place over a 24 hour period for one to two weeks. The noisier dredging works, using a backackter dredger, will be carried out during the day. At night a quieter trailer suction hopper dredger will be used. Dredging operations are commonly carried out as part of normal harbour operations.
Noise from dredging would depend on proximity of dredging to receptor locations. Taking the separation distance from the Site boundary to receptor locations, the typical noise impacts from dredging are shown in Table 8-11. The magnitude of impact has been assessed against night- time significance criteria.
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Table 8-11 Significance of Predicted Dredging Noise Impacts
Highest Predicted Magnitude of Significance Sensitive Receptor Noise (L Aeq,T ) Impact of Impact dB Moderate NM1 Behind 47 Thanckes Drive 42.4 Minor Adverse Adverse
Moderate NM2 Behind 2 Albion Road 46.0 Moderate Adverse Adverse
Yonderberry Cottages (near Moderate NM3 40.9 Minor Adverse Wilcove Inn) Adverse
Moderate NM4 12 Cove Meadow 41.1 Minor Adverse Adverse
Moderate NM5 2 Pato Point 45.6 Moderate Adverse Adverse
Table 8-11 indicates that there is a potential for noise from dredging works to be slightly above the night-time significance limit of 45 dB(A) at times, but generally impacts will be below 45 dB(A) and will be over a period of one to two weeks.
There may also be a need to move plant during high tide and barges may be required to operate outside of normal daytime hours. The use of barges would however not be out of character with normal operational activities in the harbour.
Construction works on Saturday afternoon and Sundays would be considered more disturbing to local residents and the associated receptors. The need for and extent of works over a weekend will only be confirmed once a contractor has been appointed. Assuming that the same works as carried out on a weekday are carried out on a weekend, the impacts have been presented in Table 8-12. Weekend construction noise impact has been compared against the magnitude of impact criteria set out in Table 8-4 and the significance criteria in Table 8-5.
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Table 8-12 Significance of Predicted Weekend Daytime Construction Noise Impacts
Highest Predicted Magnitude of Significance Sensitive Receptor Noise (L Aeq,T ) Impact of Impact dB Moderate NM1 Behind 47 Thanckes Drive 55.6 Minor Adverse Adverse
Moderate NM2 Behind 2 Albion Road 59.2 Minor Adverse Adverse
Yonderberry Cottages (near Moderate NM3 54.2 Minor Adverse Wilcove Inn) Adverse
Moderate NM4 12 Cove Meadow 54.3 Minor Adverse Adverse
Moderate NM5 2 Pato Point 58.9 Minor Adverse Adverse
Construction works on a Saturday afternoon (after 1300) and works on a Sunday are likely to be below 60dB(A) and would be considered Moderate Adverse.
It is possible that crew living on board ships berthed alongside at Devonport may be affected by noise and vibration associated with night time construction activity. However it would be very difficult to assess this impact and there are also a number of factors that are unknown (including mooring locations, dates when vessels will be present and durations, etc.).
More detailed construction noise predictions would be possible once a detailed method statement and full inventory of plant is available. This could be carried out for example through a Section 61 Consent Application in terms of the Control of Pollution Act (1974). Section 61 is a voluntary process and would require agreement with the Local Council.
Given the distance to receptor locations, it is unlikely that vibration impacts will be experienced at any sensitive receptor locations.
Peer reviewed literature indicates that vibration from construction activities such as use of piling rigs is unlikely to impact on receptors more than 50-100m from source. Vibration impacts from construction have therefore not been considered. 8.6.2 Operation
In the absence of detailed design information, the assessment has considered current background noise levels at receptor locations and suggested noise limits for plant that will need to be met at detailed design stage.
Operation of the tank farm and use of the loading facility (in terms of the hours of operation and frequency of use) are not expected to change as a result of the project. The jetty is operational 07:30 – 16:00 Monday to Saturday with the notable exception of service to/from replenishment tankers which are alongside for approximately 72hours, once a month, Total annual occupancy
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for vessels alongside is approximately 30% and 60% for the main jetty and pontoon jetty respectively.
Plant to be installed on site would be designed to ensure that noise from operational plant is not disturbing to local residents.
In accordance with BS4142, a +5dB penalty to account for any tonal characteristic of the plant noise has been considered in calculating the plant noise limit. BS4142 indicates that if the rating level is more than 10 dB below the measured background noise level then this is a positive indication that complaints are unlikely.
With service to/ from replenishment tankers indicated to take place at night, plant noise limits would need to be set against measured background night-time noise levels. Table 8-8 indicates that background (L A90 ) noise levels are very low at night, with L A90 levels below 30dB(A) measured at NM1, NM3 and NM5.
Pato Point (NM5) and Albion Yard represent the closest points to operational plant. Pato Point also presents low background noise levels (24.4 dB). This would indicate that, in accordance with BS4142, the noise rating level for plant noise would need to be below 24.4 dB.
It is however stated in BS4142 that this method is not suitable for assessing the noise measured inside buildings or when the background and rating noise levels are both very low. It is indicated in BS4142 that for the purposes of this standard, background noise levels below about 30dB and rating levels below about 35 dB are considered to be very low.
Considering the limitations in BS4142, the criteria for ‘Good’ internal noise levels in bedrooms and living rooms in BS8233 have been considered. BS8233 indicates an internal noise level of 30dB in an unoccupied living room or bedroom. Taking a 10dB reduction for an open window, this would equate to an external noise level of 40dB at the façade of the building.
The Lower Exposure Limit in the Control of Noise at Work Regulations 2005 (the Noise Regulations) of 80dB has been assumed. Calculating attenuation of noise with distance from source, a combined noise limit for plant to be installed on site has been calculated.
Table 8-13 Calculated Noise Limit for Operational Plant to be Installed on Site Predicted Tonal Noise Distance Plant Noise Receptors Penalty Rating Jetty (m) Limit dB(A) (BS 4142) Impact (L Ar,Tr ) NM1 Behind 47 Thanckes Drive 740 80 5 22.6
NM2 Behind 2 Albion Road 490 80 5 26.2
Yonderberry Cottages (near NM3 876 80 5 21.1 Wilcove Inn)
NM4 12 Cove Meadow 860 80 5 21.3
NM5 2 Pato Point 510 80 5 25.8
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Given the low background noise levels and the likelihood that plant noise will be noticeable at night, it is recommended that an external noise level of 35dB (L Ar,Tr ) be achieved. This would be in line with the limit for the noise rating level rating level for BS4142 to be considered a valid method of assessment.
If plant noise levels on site comply with the Lower Exposure Limit of 80 dB(A) as stipulated in the Control of Noise at Work Regulations, a noise rating level of 26.2dB(A) is predicted at Albion Yard and 25.8 dB(A) at Pato Point.
Operations at the new jetty facility are expected to generate noise levels similar to those currently generated on site. The most significant noise is probably the normal operating noise of a ship, which will be similar to the other ships berthed at the current jetty.
Operational noise impacts will however alter with activities being located slightly closer to Wilcove and further from Torpoint. 8.6.3 Decommissioning
There are no details of decommissioning works and the plant to be used. Plant to be used for decommissioning works and methods to be used may have changed greatly by the time decommissioning is carried out.
For the purposes of this assessment it has been assumed that plant to be used for decommissioning will be similar to the plant to be used for removal of the existing jetty structure and that noise impacts will be similar, 8.7 Cumulative Effects
Refer back to chapter 3.6 for cumulative effects and a description of the developments considered.
At present there are three reasonably foreseeable developments within the vicinity of the proposed development that have been considered for cumulative impacts, as advised by statutory consultees and DIO:
° MOD Forward Operating Base at Kinterbury Point ° MOD Refurbishment and Operation of Trevol Jetty ° South West Devon Waste Partnership Combined Heat and Power Plant ° The South West Devon Waste Partnership Combined Heat and Power Plant presents the closest development at approximately 1200m from the proposed jetty location. Construction and demolition noise impacts are predicted to be below 55dB at 500m. Given the separation distance from the Combined Heat and Power Plant, cumulative construction noise impacts are unlikely. ° The separation distance to the MOD Forward Operating Base at Kinterbury (over 2000m) and the MOD Refurbishment and Operation of Trevol Jetty (1600m) and the fact that there is no direct line of sight between these sites and the Thanckes jetty mean that there will not be cumulative noise impacts.
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8.8 Summary
Weekday daytime construction noise impacts are predicted to be Slight or Moderate Adverse at Receptor locations. Particularly noisy activities such as piling will be confined to daytime hours.
Daytime works on weekends (Saturday after 1300 and Sundays) are indicated to result in Moderate Adverse . The assessment of weekend construction noise has however assumed that similar activities will take place over a weekend as carried out on a typical weekday. The extent and nature of weekend working will only be established once a contractor has been appointed. Any works carried out outside of normal work hours would need to be agreed with the local EHO.
At night there will be a need to carry out dredging over a period of one to two weeks. Dredging is commonly carried out in the harbour and would not be totally out of character. The dredging noise impacts will be of short duration and are predicted to be Moderate Adverse .
There will also be a need to move construction plant at high tide using barges. This may at times require barges to operate at night. The movement of barges will however not be out of character with normal harbour operations.
Further reduction in construction noise impacts is possible through the adoption of BPM, as outlined in Section 72 of the Control of Pollution Act (1974). The mitigation measures to be implemented would be selected to suit the specific circumstances at each construction area, considering the nature of the works, the plant to be used and the distance and position of the receptor locations in relation to the works.
Dredging and piling works will involve the use of jack-up barges and floating plant, which allows little scope for use of acoustic barriers.
The effectiveness of any screening would also depend on the properties of the screening material, the location of the acoustic screen in relation to the source, the height of the acoustic screen and the height of the receptor in relation to the noise source. As a rule of thumb, when there is no clear line of sight between noise source and receptor, a 10dB reduction in noise level can be expected.
At detailed design stage it has been indicated that plant to be installed on site should meet a cumulative site noise limit of 80dB, which is the Lower Exposure Limit in the Control of Noise at Work Regulations. This would ensure a noise rating level (L Ar,Tr ) of below 30dB is met at the closest receptor locations at Pato Point and Albion Yard.
Selection of low-noise operational plant, the correct installation of this plant and the use of acoustic enclosures where necessary and possible will ensure that the required plant noise limit is met.
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Table 8-14 Noise Impact Summary Table
Impact description Temporary/Permanent Significance rating
Jetty Removal and Temporary Daytime construction noise Construction Noise Impacts impacts are Slight or Moderate Adverse Night-time construction noise impacts are Moderate Adverse
Operational Noise Impacts Permanent Negligible impact if appropriate measures are considered during detailed design.
Decommissioning Temporary Daytime construction noise impacts are Moderate Adverse Night-time construction noise impacts are Moderate Adverse
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9 LANDSCAPE AND VISUAL IMPACT ASSESSMENT 9.1 Introduction
This report considers the landscape and visual implications of the Development; a description of the Development is provided in Chapter 2. Landscape is defined in the European Landscape Convention as ‘...an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors’ (Ref 9-1). Visual or visual amenity considerations relate specifically to the views of a landscape afforded to people. These separate but related issues form the basis for landscape and visual impact assessment (LVIA). 9.2 Regulatory and Policy Framework
This impact assessment has been undertaken in accordance with current national legislation, and national, regional and local plans and policies relating to landscape and visual considerations in the context of the Development. A summary of the relevant legislation and policies, the requirements of these policies and the Development response has been provided in the table below.
Table 9-17 Landscape and Visual Regulatory and Policy Framework
Policy/Legislation Summary of Requirements Development Response
National Planning Policy Requires landscape to be taken The Development does not fall within a Framework (Ref 9-2) into account in the planning protected landscape; however the Tamar process through protection and Valley AONB is situated approximately enhancement of landscapes. 1km north west of the Development at its Confirms National Parks and nearest point. The setting of the AONB Areas of Outstanding Natural has therefore been taken into account in Beauty (AONB) have the highest this assessment, along with wider status of protection in relation to landscape character and visual amenity landscape and scenic beauty considerations. There are not anticipated (under the National Parks and to be significant impacts on landscape Access to the Countryside Act, character or the setting of the AONB as a 1949, and Countryside and result of the Development. Rights of Way Act, 2000, respectively).
Caradon Local Plan First Requires character and The Tamar Valley AONB is situated Alteration (August 2007) appreciation of AONBs to be approximately 1km north west of the : Policy CL7 - taken into account in respect of Development at its nearest point. Views Development Near Areas development near these from and to the AONB have been taken of Outstanding Natural designated areas. Development into account in this assessment. There Beauty or Heritage Coast which will be unduly prominent are not anticipated to be significant from view points within such impacts on these views as a result of the (Ref 9-3) areas or will adversely affect the Development. view towards such areas from
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Policy/Legislation Summary of Requirements Development Response roads, footpaths, bridleways and other public places will not be acceptable.
9.3 Methodology 9.3.1 Introduction
The assessment process has been carried out based on ‘Guidelines for Landscape and Visual Impact Assessment: Third Edition’ (Ref 9-4). 9.3.2 The Study Area
The overarching Study Area extends to a 2.5 km radius from the site (refer to Drawing 9-1). Beyond this distance the Development would not be readily perceptible within the landscape.
To refine the assessment, a Zone of Theoretical Visibility (ZTV) has been generated within the Study Area, which represents the theoretical area from which any part of Development may be seen (refer to Drawing 9-1). ZTVs are based on bare ground data, with any ridgelines, plateaux and valleys reflected in the extent of predicted visibility. ZTVs do not take into account local conditions such as subtle variations in landform, built Development or vegetation cover, which significantly reduce the extent of actual visibility.
The ZTV was modelled using a Digital Terrain Model (DTM), taking into account the curvature of the earth and assuming a viewer height of approximately two metres above ground level. DTM data was derived from Ordnance Survey (OS) Raster 50 data (elevation data on a fifty metre grid). ZTV output was overlaid on OS mapping, with an overview reproduced at 1:25,000 scale.
Designations which are relevant to matters of landscape and visual amenity and the proposed Development have also been identified (refer to Drawing 9-1). 9.3.3 Establishing Baseline Conditions
Baseline conditions are defined by landscape character and respective sensitivity, together with visual amenity (as represented by views) and the sensitivity of visual receptors (or potential viewers), in accordance with the criteria set out below.
Table 9-2 Definitions of Landscape Sensitivity
Level of Definition of Sensitivity Examples Sensitivity
High Value: Typically of high importance and rarity, national scale, and limited potential for substitution (e.g. National Parks or Areas of Outstanding Natural Beauty). *Susceptibility to change: Landscape unlikely to tolerate the change proposed.
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Level of Definition of Sensitivity Examples Sensitivity
Medium Value: Typically of moderate importance and rarity, regional scale, and limited potential for substitution (e.g. Registered Historic Parks and Gardens, Conservation Areas). *Susceptibility to change: Landscape has the potential to tolerate the change proposed.
Low Value: Typically of low importance and rarity, local scale, such as undesignated or degraded landscapes.
*Susceptibility to change: Landscape likely to tolerate the change proposed.
*The judgement concerning susceptibility to change is made by considering the nature/characteristics of the development and receiving landscape, following evaluation of receptor value and prior to the assessment of effects.
Table 9-3 Definitions of Visual Sensitivity
Level of Definition of Sensitivity Examples Sensitivity
High Value: Typically nationally recognised/important (e.g. from landscape of national importance); Susceptibility to change: Views from residential properties; where appreciation of affected views may be the principal activity.
Medium Value: Typically regionally/locally recognised/important (e.g. from landscape of regional/local importance); Susceptibility to change: Views from public rights of way, cycle trails, public open space; where attention may be focused on an affected view.
Low Value: Typically views not recognised/of importance;
Susceptibility to change: Views from roads and railways which are transient due to travelling through the landscape; places of work or commercial properties; where attention is unlikely to be focussed on affected views.
Relevant desk-based information has been obtained from Natural England, Cornwall Council, and Ordnance Survey. Field survey work was undertaken during summer 2013. At this time of year, deciduous trees and shrubs are predominantly with leaves such that there is less visibility within the landscape than in winter months (when there is not deciduous leaf cover). Viewpoints have been selected to represent the range of visual receptors, that is those who would have a view of the Development, and views affected, against which visual sensitivity was assessed. Viewpoint photographs were taken in accordance with Landscape Institute guidance (Ref 9-5) using a digital single lens reflex (SLR) camera, with lens selected to provide the digital equivalent of 50 mm focal length for a 35 mm film format SLR camera. Photographs were then stitched together to generate a panorama spanning up to approximately ninety degrees in the
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direction of the Development (the extent of view that would be experienced by the viewer at the selected viewpoint, when facing in that direction). 9.3.4 Assessing Effects
The significance of impacts is determined using the approach described in Chapter 3 of this ES.
The criteria and threshold matrices used to assess the magnitude of impact and significance of landscape and visual effects are set out below. Impacts are assessed at the construction/decommissioning phases and during the operational phase.
Table 9-4 Assigning Magnitude of Landscape Impact
Level of Definition of Magnitude Magnitude
High Total loss of or major alteration to key landscape characteristics such that landscape character will be fundamentally changed.
Medium Partial loss of or alteration to key landscape characteristics such that landscape character will be partially changed.
Low Minor loss of or alteration to key landscape characteristics such that landscape character will be similar to the baseline conditions.
Negligible Very minor loss or alteration to key landscape characteristics such that change in landscape character will be barely distinguishable from the baseline conditions, approximating to the “no change” situation.
Table 9-5 Assigning Magnitude of Visual Impact
Level of Definition of Magnitude Magnitude
High Major change in existing view.
Medium Partial change in existing view.
Low Minor change in existing view such that view largely unchanged.
Negligible Very inconspicuous change in existing view, approximating to the ‘no change’ situation.
A combined assessment of sensitivity and magnitude is undertaken to determine how significant an effect is, as set out in Table 9-6 below.
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Table 9-6 Significance Matrix
High Moderate Moderate / Major Major
Medium Minor / Moderate Moderate Moderate / Major
Low Minor Minor / Negligible Moderate
Negligible Negligible Negligible Negligible MAGNITUDE MAGNITUDE
Low Medium High
SENSITIVITY
Effects may be positive or negative. Only those effects that are recorded as major negative are considered to be significant in respect of the decision making process (as shaded on Table 9-6).
Photomontages were produced in accordance with LI guidance (Ref 9-5). A photomontage is a computer rendered image of the Development superimposed onto an existing photograph, representing the likely appearance of the Development. 9.3.5 Consultation
An EIA Scoping Opinion, requesting a landscape and visual impact assessment for the Development, was prepared by Cornwall Council on 13 th February 2013. Michelle Billing, Senior Development Officer at Cornwall Council was further consulted regarding the assessment on 13th August 2013. Viewpoints were requested from the Scheduled Monument to the north of the Development (Barne Barton) and to the South of the Development, on the Devon side of the river (Plymouth). These locations are not publically accessible, however, Viewpoints 5 and 7 have been included as the nearby representative viewpoints. 9.4 Description of the Baseline Conditions 9.4.1 Landscape
Natural England (previously the Countryside Agency) has produced a landscape character assessment of England entitled ‘Countryside Character’ (Ref 9-6). The site lies at the edges of National Character Area 152, the ‘Cornish Killas’ and Area 151, South Devon. More locally, the site lies within CA25 ‘Lynher and Tiddy River Valleys’ Landscape Character Area identified in the Cornwall and Isles of Scilly Landscape Character Study (Ref 9-7), which describes this area as having the following key characteristics:
• Estuarine landscape of winding inlets, extensive intertidal zones, with intertidal Mudflats, large areas of Coastal Saltmarsh and a Saline Lagoon; very well used by water sport enthusiasts.
• Tidal river valleys with Coastal Saltmarsh and wetlands, grading to mixed farming; many hedgerow trees and tree lines along watercourse.
• Parkland at Mt Edgcumbe, Antony and Port Eliot.
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• Small steep - sided upper river valleys inland with mix of farmland and woodland, with mature trees on network of Cornish hedges adding to wooded feel.
• Farmland is a mix of pasture, arable, fruit and flower growing, with estate land with deer park and much beech.
• Maze of narrow enclosed winding lanes throughout, with many trees on boundaries.
• Visual prominence of Torpoint and major conurbations in neighbouring LCAs: Plymouth and Saltash.
The site falls within the Hamoaze estuarine landscape at the edge of Thanckes Oil Fuel Depot, which is largely defined by utilitarian military buildings and oil storage infrastructure. The wider landscape comprises the wooded coves and headlands at the edge of the Tamar Valley AONB, to the north-west, Torpoint, to the south, and the major conurbation of Plymouth to the north and west. The area of Plymouth nearest to the site comprises Devonport Docks, which provide an immediate backdrop of substantial infrastructure.
Landscape Sensitivity Whilst parts of the local landscape fall within the Tamar Valley AONB, the immediate site context is largely defined by a mix of infrastructure and urban settlement at the edges of the Hamoaze estuary, outside of the AONB, such that development of the type proposed could be integrated with the local landscape without resulting in significant disruption to local landscape character. Overall, taking into account the fact that the immediate landscape is not designated together with scope to accommodate development of the type proposed, this landscape is considered to have a medium sensitivity . 9.4.2 Visual Amenity
The ZTV relating to the Development, which does not take account of land cover, is illustrated on Drawing 9-1. This extends northwards to Saltash, eastwards to Plymouth, southwards into the Hamoaze estuary, and westwards to Antony Park. Extensive vegetation and built form in the local landscape significantly reduce the extent of actual visibility. In particular, views from the Antony Park Registered Park and Garden are obstructed by vegetation. Views from Plymouth are largely obstructed by the dockyard infrastructure at the edge of the Hamoaze, however there will be occasional views across/through the infrastructure to the Development. Taking account of this, visual receptors include properties, public rights of way, and transport corridors in Wilcove, Wearde Quay (within the Tamar Valley AONB), Torpoint and Plymouth, as represented by Viewpoints 1 to 8. These viewpoints form the basis for visual assessment below. Viewpoint photographs are provided within Drawings 9-2 to 9-5.
Viewpoint 1: View from Public Footpath at Pato Point, Looking South East This view represents users of the Public Footpath, together with the private road and nearby residential properties. Taking these receptors into account, visual sensitivity is considered to be high . The foreground comprises the immediate shoreline and Cangapool bay, across which lie a wooded headland, the site and Thanckes Oil Fuel Depot Jetty. The wider backdrop comprises dockyard infrastructure at Devonport and the Plymouth urban area beyond.
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Viewpoint 2: View from Wilcove Waterfront, Looking South East This view represents users of the waterfront and adjacent residential properties at this location. Taking into account these receptors, visual sensitivity is considered to be high . The foreground comprises Wilcove waterfront and Cangapool bay, across which lie a wooded headland, the site and Thanckes Oil Fuel Depot Jetty. The wider backdrop comprises dockyard infrastructure at Devonport and the Plymouth urban area beyond.
Viewpoint 3: View from Minor Road at Wilcove Village Hall, Looking South East This view represents users of the minor road, together with the Village Hall and nearby residential properties. Taking these receptors into account, visual sensitivity is considered to be high . The foreground is formed by agricultural fields, properties and tree cover, which partly restrict views across Cangapool bay to the site, Thanckes Oil Fuel Depot Jetty and a wooded headland where the Oil Fuel Depot storage tanks are visible above the treeline. The wider backdrop, views to which are also partially restricted, comprises dockyard infrastructure at Devonport and the Plymouth urban area beyond.
Viewpoint 4: View from Minor Road between Wilcove and Coombe Park, Looking South East This view represents users of the minor road and residential properties at the edge of the AONB. Taking into account these receptors visual sensitivity is considered to be high . This elevated view is from a fieldgate, with foreground comprising agricultural fields, which slope down to the edge of Wilcove and that adjoin the Oil Fuel Depot, where a fuel tank is visible. The outer reaches of Cangapool bay, including the site, are visible in the middle ground with a backdrop of dockyard infrastructure at Devonport and the Plymouth urban area beyond.
Viewpoint 5: View from Wearde Quay, looking South East This view represents users of the minor road, quay, residential properties, and the setting of nearby Scheduled Monument, all within the Tamar Valley AONB. This viewpoint is also a similar distance and in a similar direction from the Development as the Scheduled Monument at Barne Barton (which is not publically accessible) and is therefore also broadly representative of this location. Taking these considerations into account, visual sensitivity is considered to be high . The view is largely defined by views across the Hamoaze/Lynher River with a distant backdrop of wooded headlands, including the location of the site, and dockyard infrastructure at Devonport.
Viewpoint 6: View from Public Footpath at Torpoint, Looking North East This view represents users of the Public Footpath and nearby residential properties. Taking this into account, visual sensitivity is considered to be high . Views from the Public Footpath are largely obscured by existing vegetation. Glimpsed views are available across Thanckes Lake to Thanckes Oil Fuel Depot Jetty and fuel tanks, and the urban area of Plymouth beyond. From residential properties, which back onto Thanckes Lake to the south and on higher ground there are clearer views toward the site than from the Public Footpath, however there is no public access to these properties.
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Viewpoint 7: View from Torpoint Ferry, Looking North West This view represents users of the Torpoint Ferry, which carries pedestrian and vehicular traffic. This viewpoint is also a similar distance and in a similar direction from the Development as the nearby Scheduled Monuments (which are not publically accessible) and residential properties in Plymouth and is therefore also broadly representative of these locations; it should be noted, however, that dockyard infrastructure at the edge of the estuary heavily restricts views from these areas of Plymouth. Taking these considerations into account, visual sensitivity is considered to be high . The view is largely defined by views over the Hamoaze estuary to Thanckes Oil Fuel Depot Jetty and fuel tanks, framed by Torpoint and the dockyards at Devonport. The conurbation of Saltash forms a very distant backdrop.
Viewpoint 8: View from Blackhouse Park, Plymouth, Looking North West This view represents users of the Public Park and visitors to this setting of the Scheduled Monument. Taking this into account, visual sensitivity is considered to be high . The elevated viewpoint allows views over the immediate Plymouth urban area, dockyards and more distant backdrop formed by the Hamoaze estuary, in which the site lies, beyond. 9.5 Design and Mitigation 9.5.1 Construction and Demolition
Construction and demolition best practice would be employed to limit landscape and visual disruption; measures will include locating the site compound within the existing Thanckes Oil Fuel Depot and minimising temporary land use outside of the depot. 9.5.2 Operation
The Development has been sited and designed so that the proposals form similar landscape elements to existing infrastructure, particularly in terms of built form, limiting landscape and visual disruption. 9.6 Assessment of Effects 9.6.1 Construction Phase Effects
Construction phase activity would introduce temporary elements within the landscape. Activities located within the existing, land based Oil Fuel Depot would generally only be perceived within the context of the existing infrastructure and as a result wider landscape character and quality would remain intact. Activities within the Hamoaze would be more widely visible however, considering the nature of construction/demolition activities, particularly their very transient characteristics, the magnitude of landscape and visual impacts is considered to be low negative , and, taking into account some high sensitivities described in Section 9.4, the overall significance of landscape and visual effects during construction is considered to be moderate negative .
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9.6.2 Operational Phase Effects
Landscape The site does not fall within any designated landscapes. The Development would result in minor alteration to landscape characteristics, through construction of Thanckes Oil Fuel Depot Jetty in a location very close to the current jetty and of similar built form. The current jetty would subsequently be demolished. Lightweight gantries would be constructed atop of several of the existing fuel storage tanks. Although the gantries would increase the height of the tanks, their metal lattice construction would be similar to the tank’s existing walkways. As a result there would be only minor change to baseline landscape character and the magnitude of landscape impact is therefore considered to be low negative . Taking into account medium landscape sensitivity, the overall significance of landscape effect is considered to be minor negative . Visual Amenity
Viewpoint locations are shown on Drawing 9-1. Photographs and photomontages are provided within Drawings 9-2 to 9-7. Viewpoint 1: View from Public Footpath at Pato Point, Looking South East The foreground would continue to comprise the immediate shoreline and Cangapool bay. The Development would lie across the bay and fall closer than the current jetty, but would continue to sit against a wider backdrop of dockyard infrastructure at Devonport and the wider urban area beyond. As a result the magnitude of visual impact is considered to be low negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be moderate negative .
Viewpoint 2: View from Wilcove Waterfront, Looking South East The foreground would continue to comprise Wilcove waterfront and Cangapool bay. The Development would lie across the bay and fall closer than the current jetty, but would continue to sit against a wider backdrop of dockyard infrastructure at Devonport and the wider urban area beyond. On the headland, lightweight lattice gantries added atop existing storage tanks would be visible. These structures would be visually permeable. As a result the magnitude of visual impact is considered to be low negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be moderate negative .
Viewpoint 3: View from Minor Road at Wilcove Village Hall, Looking South East The foreground would continue to comprise agricultural fields, properties and vegetation. The Development would lie across the bay and fall closer than the current jetty, but would be partially obstructed by intervening vegetation and continue to sit against a wider backdrop of dockyard infrastructure at Devonport and the wider urban area beyond. Lightweight lattice gantries added atop existing storage tanks would increase the visibility of these features on the headland. However, the additional structures would be visually permeable and within the context of existing infrastructure. As a result the magnitude of visual impact is considered to be low negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be moderate negative .
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Viewpoint 4: View from Minor Road between Wilcove and Coombe Park, Looking South East The Development would be visible at the outer reaches of Cangapool bay, introduced to the middle ground. The Development would be largely screened by vegetation, with a backdrop of dockyard infrastructure at Devonport and the Plymouth urban area beyond. As a result the magnitude of visual impact is considered to be low negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be moderate negative .
Viewpoint 5: View from Wearde Quay, looking South East The Development would be largely screened from view at this location by the headland at Pato Point, with the jetty head and associated moored vessels visible at approximately 2km distant and resulting in a very inconspicuous change in the existing view. As a result, the magnitude of visual impact is considered to be negligible negative. Taking into account high visual sensitivity, the overall significance of visual effect is considered to be negligible negative.
Viewpoint 6: View from Public Footpath at Torpoint, Looking North East The Development would be a greater distance away from this viewpoint than the existing jetty however it would be larger in width and mass. Lightweight lattice gantries added atop existing storage tanks would increase the height of these features on the headland. However, the additional structures would be visually permeable and within the context of existing infrastructure. As a result, the magnitude of visual impact is considered to be negligible negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be negligible negative.
Viewpoint 7: View from Torpoint Ferry, Looking North West The Development would be a greater distance away from this viewpoint than the existing jetty however it would be larger in width and mass. Lightweight lattice gantries added atop existing storage tanks would increase the height of these features on the headland. However, the additional structures would be visually permeable and within the context of existing infrastructure. As a result, the magnitude of visual impact is considered to be negligible negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be negligible negative.
Viewpoint 8: View from Blackhouse Park, Plymouth, Looking North West This elevated viewpoint allows views over the immediate Plymouth urban area, dockyards and more distant backdrop formed by the Hamoaze estuary, in which the site lies, beyond. The Development would form a distant, inconspicuous element in the view. As a result, the magnitude of visual impact is considered to be negligible negative . Taking into account high visual sensitivity, the overall significance of visual effect is considered to be negligible negative.
Overall significance of visual effect, taking into account the range of views and visual receptors affected, is considered to be minor negative.
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9.6.3 Decommissioning Phase Effects
Decommissioning phase activity would introduce temporary elements within the landscape. Activities located within the existing, land based Oil Fuel Depot would generally only be perceived within the context of the existing infrastructure and as a result wider landscape character and quality would remain intact. Activities within the Hamoaze would be more widely visible however, considering the nature of construction/demolition activities, particularly their very transient characteristics, the magnitude of landscape and visual impacts is considered to be low negative , and, taking into account some high sensitivities described in Section 9.4, the overall significance of landscape and visual effects during decommissioning is considered to be moderate negative . 9.7 Cumulative Effects
There are three reasonably foreseeable developments within the vicinity of the proposed development, identified for consideration of cumulative impacts, as advised by statutory consultees and the Defence Infrastructure Organisation.
The three proposed developments, identified in Drawing 3-1 are as follows:
• MOD Forward Operating Base at Kinterbury Point
• MOD Refurbishment and Operation of Trevol Jetty
• South West Devon Waste Partnership Combined Heat and Power Plant
The proposed development at Kinterbury Point and refurbishment of Trevol Jetty are located to the south of Torpoint, approximately 1-1.5km distant from the proposed development. The local topography and built form means it would be unlikely that they would be visible from any of the viewpoints identified. From the Hamoaze estuary and adjacent land to the south, it is likely that these two sites and the proposed Thanckes Jetty will be visible in combination. However, given that all of the proposals would be seen within the distance and against a backdrop of existing settlement and marine infrastructure, it is considered that the cumulative impacts of the combined sites would not be significant .
The South West Devon Waste Partnership Combined Heat and Power Plant may be visible in conjunction with the proposed development, principally from the south (viewpoints 6,7 and 8). However given its distance at approximately 1.5km from the proposed development and its setting within existing marine infrastructure and the Plymouth urban area, which already define the backdrop within these views, it is considered that the cumulative impacts would not be significant.
9.8 Summary
The landscape and visual implications of the proposed Development have been considered through comprehensive landscape and visual impact assessment, in accordance with best practice guidance. The site falls within the Hamoaze estuarine landscape and is not subject to landscape designations. The wider landscape is made up of the Tamar Valley Area of
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Outstanding Natural Beauty, Torpoint and the Plymouth conurbation (including Devonport Docks). Visual receptors, or those who would have a view of the Development, include properties, public rights of way, and transport corridors in Wilcove, Wearde Quay (within the Tamar Valley AONB), Torpoint and Plymouth.
The Development would result in minor alteration to landscape characteristics, through construction of Thanckes Oil Fuel Depot Jetty in a location very close to the current jetty and of similar built form. The current jetty would subsequently be demolished. Lightweight gantries constructed atop of several of the existing fuel storage tanks would increase the height of the tanks, but their metal lattice construction would be similar to the tank’s existing walkways. In the majority of available views, the Development would be seen against a backdrop of infrastructure formed by Devonport Docks, such that visual amenity would not substantially change. As a result there would not be significant impacts on landscape character and visual amenity.
Table 9-6 Landscape and Visual Impact Summary Table
Impact description Temporary/ Proposed Significance Significant permanent mitigation rating effect measures
Construction Phase Temporary Moderate negative Not significant Impact – Landscape & Visual Amenity Temporary landscape and visual disruption.
Operational Phase Permanent Minor negative Not significant Landscape Overall, landscape character, composition and quality would remain largely unchanged.
Decommissioning Temporary Moderate negative Not significant Phase Impact – Landscape & Visual Amenity Temporary landscape and visual disruption.
Visual Amenity Permanent Minor negative Not significant In the majority of available views the Development would result in discernible change however this change would generally not be uncharacteristic of views, and visual quality would remain largely intact.
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10 Conclusion
In conclusion there are no temporary or permanent significant effects identified for all topics following the implementation of the mitigation measures. In some cases there will be a positive effect in reducing the potential risk to the environment.
Water Contamination and Sediment Quality The activities associated with the construction and on-going operation of the proposed Development and the demolition of the existing jetty, with potential to cause impact to water quality are similar to those already carried out in the estuary.
During the construction phase Temporary Slight Negative impacts are anticipated for both the land and marine based activities, with the use of mitigation measures that are identified within Section 5.5.
The operational scheme as a whole provides a beneficial environmental effect as the new and improved infrastructure will significantly reduce the potential for pollution incidents to occur. During the operation impacts are classified as of Permanent Positive Moderate/Large impact .
The decommissioning of both the existing jetty and the proposed jetty are considered as having Temporary Slight Negative impact related to the removal of hazardous substances and foreign materials from entering the watercourse will be minimised through mitigation measures.
As a result there would not be significant effects on Water Contamination and Sediment Quality
Ecology No significant effects on any ecological receptors are anticipated during construction and decommissioning of the existing jetty. Although the subtidal habitats within the Site are located within the Plymouth Sound and Estuaries SAC, given the relatively small footprint of the works and the impoverished nature of the habitats present, no significant effects are predicted. The site is located close to the Tamar Estuaries Complex SPA and St John’s Lake SSSI, but the habitats in the vicinity of the Site are not of particular importance to birds associated with these designated sites. Pollution prevention measures that would be put in place will ensure no significant impacts on any of the surrounding designated sites, valuable habitats or species as a result of increased siltation and pollution during construction. Construction has been timed to avoid impacts on migratory fish, a feature of International importance.
No significant effects on any ecological receptors are anticipated during operation. Mitigation measures have been proposed which would minimise disturbance of sediment, contain migration of sediment and reduce the risk of a pollution incident. Furthermore, the new, upgraded facility will reduce the potential for a pollution incident to occur.
Archaeology and Cultural Heritage The significance of the effect of construction upon the known archaeology is considered to be Permanent Slight. No mitigation is considered to be warranted and would therefore overall impact is not predicted to be significant.
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The operational and decommissioning activities of both the existing and proposed jetty are considered as Permanent Slight Impact upon known archaeology. Therefore the overall effect is not predicted to be significant.
There is low potential for as yet unrecorded shipwreck archaeology or submerged prehistoric remains to be present within the site, the value of which is Uncertain. However, although the potential is low, the precautionary principle has been used. Remains of submerged prehistory would not be anticipated to exceed medium heritage value , while remains of wrecks within the site could potentially be of high heritage value . The likelihood of either remains occurring is considered to be very low. Such potential remains could incur impact of up to a high magnitude of change , if encountered within the areas of proposed dredging. This would result in, at most, a Major Significance of Effect . Although this significance of effect has been identified in relation to remains which have a very low potential of occurring within the proposed development site, an Archaeological Watching Brief would be necessary. The residual effect will be slight and that; therefore the overall impact is not predicted to be significant.
As a result there would not be significant effects on archaeology and cultural heritage.
Noise and Vibration The daytime construction noise impacts of are considered to be Slight or Moderate Adverse , with night time impacts anticipated to be Moderate Adverse . Both of these impacts will be Temporary. Given the distance to receptor locations it is unlikely that vibration impacts will be experienced at any sensitive location. Predicted construction noise levels for both daytime and night-time are predicted to be below threshold values set out in BS5228 and would therefore not be considered significant.
Operations at the new jetty facility are expected to generate noise levels similar to those currently generated on site. The most significant noise is probably the normal operating noise of a ship, which will be similar to the other ships berthed at the current jetty. Permanent operational noise impacts will be negligible if appropriate mitigation measures are considered during detailed design.
Decommissioning noise impacts would result in a Temporary Moderate Adverse impact during the daytime and Temporary Moderate Adverse impacts during the night time. Decommissioning noise impacts are predicted to be below threshold values set out in BS5228 and would therefore not be considered significant.
As a result there would not be significant effects on noise and vibration.
Landscape and Visual Impact Assessment The Development would result in minor alteration to landscape characteristics, through construction of Thanckes Oil Fuel Depot Jetty in a location very close to the current jetty and of similar built form. This would be a Temporary Moderate Negative impact and would therefore not be considered significant.
The current jetty would subsequently be demolished resulting in Temporary landscape and visual disruption. This would be a Temporary Minor Negative impact and would therefore not be considered significant.
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During the operational phase the majority of available views the Development would result in discernible change however this change would generally not be uncharacteristic of views, and visual quality would remain largely intact. This would be a Permanent Minor Negative impact and would therefore not be considered significant.
As a result there would not be significant effects on landscape character and visual amenity.
Cumulative Effects Cumulative effects associated with Thanckes OFD Development have been considered. These are the combined effects of Thanckes OFD with other developments within the vicinity of the site, the combined effects of Thanckes OFD with MOD Forward Operating Base at Kinterbury Point, MOD Refurbishment and Operation of Trevol Jetty and South West Devon Waste Partnership Combined Heat and Power Plant, and the combined effects of different environmental aspects of Thanckes OFD development on a particular receptor.
A cumulative impact assessment has been undertaken within the environmental statement for the areas above. No likely cumulative effects are anticipated during the construction and operational phase of these other developments.
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GLOSSARY AND ABBREVIATIONS
Acoustic barrier Solid walls or partitions, solid fences, earth mounds, buildings, etc. used to reduce noise, without eliminating it.
ADD Approved Dredge Depth
ADS Archaeological Data Service AGSV Area of Great Scientific Value AL Action Levels Ambient sound The totally encompassing sound in a given situation at a given time, usually composed of sound from all sources near and far.
AMAA Ancient Monuments and Archaeological Areas Act 1979
AONB Area of Outstanding Natural Beauty Background Noise Background noise is the term used to describe the noise measured in the absence of the noise under investigation. It is described as the average of the minimum noise levels measured on a sound level meter and is measured statistically as the A- weighted noise level exceeded for ninety percent of a sample period. This is represented as the L90 noise level (see below).
BAP Biodiversity Action Plan BC Before Christ Best Practicable Means "Practicable" means reasonably practicable having regard among (BPM) (COPA 1974) other things to local conditions and circumstances, to the current state of technical knowledge and to the financial implications. The means to be employed include the design, installation, maintenance and manner and periods of operation of plant and machinery, and the design, construction and maintenance of buildings and acoustic structures. BGS British Geological Survey BP Before present BPM Best Practicable Means BS British Standard bsl Below sediment level. This was the reference point used when drilling the boreholes, based on the level at which sediment was first encountered. BTO British Trust for Ornithology Capital Dredging Material arising from the excavation of the seabed, generally for construction or navigation purposes, in an area or down to a level (relative to Ordnance Datum) not previously dredged during the preceding 10 years Cefas Centre for Environment Fisheries and Aquaculture Science
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CBI Cornwall Biodiversity Initiative
CBWPS Cornwall Bird Watching Preservation Society
CC Cornwall Council
CD Chart Datum CDM Construction and Design Management
CEMP Construction Environmental Managment Plan
CLR Contaminated Land Report
COMAH Control of Major Accidents and Hazards Regulations
CPIG Crown Premises Inspection Group
CCTV Closed Circuit Television
CROW Countryside Rights of Way Act (2000)
CSM Conceptual Site Model
CWS County Wildlife Site
CWT Cornwall Wildlife Trust
DASSH Data Archive for Seabed Species and Habitats
DCLG Department of Communities and Local Government
Decibel [dB] The level of noise is measured objectively using a Sound Level Meter. This instrument has been specifically developed to mimic the operation of the human ear. The human ear responds to minute pressure variations in the air. These pressure variations can be likened to the ripples on the surface of water but of course cannot be seen. The pressure variations in the air cause the eardrum to vibrate and this is heard as sound in the brain. The stronger the pressure variations, the louder the sounds are heard. The range of pressure variations associated with everyday living may span over a range of a million to one. On the top range may be the sound of a jet engine and on the bottom of the range may be the sound of a pin dropping.
Instead of expressing pressure in units ranging from a million to one, it is found convenient to condense this range to a scale 0 to 120 and give it the units of decibels.
The following are examples of the decibel readings of every day
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sounds;
Four engine jet aircraft at 100m 120 dB
Riveting of steel plate at 10m 105 dB
Pneumatic drill at 10m 90 dB
Circular wood saw at 10m 80 dB
Heavy road traffic at 10m 75 dB
Telephone bell at 10m 65 dB
Male speech, average at 10m 50 dB
Whisper at 10m 25 dB
Threshold of hearing, 1000 Hz 0 dB
dB(A): A -weighted The ear is not as effective in hearing low frequency sounds as it is decibels hearing high frequency sounds. That is, low frequency sounds of the same dB level are not perceived to be as loud as high frequency sounds. The sound level meter replicates the human response of the ear by using an electronic filter which is called the "A" filter. A sound level measured with this filter switched on is denoted as dB(A). Practically all noise is measured using the A filter. The sound pressure level in dB(A) gives a close indication of the subjective loudness of the noise.
Defra Department of the Environment Food and Rural Affairs DETR Department of the Environment, Transport and the Regions
DIO Defence Infrastructure Organisations (‘the client’)
DLCCP Devonport Landing Craft Co-location Project
DTM Digital Terrain Model
EA Environment Agency
EC European Commission
EHA English Heritage Archives
EHO Environmental Health Officer
EIA Environmental Impact Assessment
EPS European Protected Species
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EQS Environmental Quality Standards
ERCCISS Environmental Records Centre for Cornwall and the Isles of Scilly
ES Environmental Statement
FEPA Food and Environment Protection Act
FFFP Film-Forming Fluoroprotein
FHSU Fleet Helicopter Support Unit
FOB Forward Operating Base
FRA Flood Risk Assessment
GAC Generic Assessment Criteria GPS Global Positioning System HA Highways Agency HER Historic Environment Record HGV Heavy Goods Vehicles HLS Helicopter Landing Site HMNB Her Majesty’s Naval Base HRA Habitat Regulations Assessment HSE Health & Safety Executive IBCs Intermediate Bulk Containers
IEEM Institute of Ecology and Environmental Management’s
IEMA Institute of Environmental Management and Assessment
IPG Integrated Projects Guide
ISGOTT International Safety Guide for Oil Tankers and Terminals
JNCC Joint Nature Conservation Committee
LBAP Local Biodiversity Action Plan
LAmax The maximum RMS A-weighted sound pressure level occurring within a specified time period. LCA Landscape Character Area Loudness A rise of 10 dB in sound level corresponds approximately to a doubling of subjective loudness. That is, a sound of 85 dB is twice as loud as a sound of 75 dB which is twice as loud as a sound of 65 dB and so on. That is, the sound of 85 dB is 400 times the
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loudness of a sound of 65 dB.
LNR Local Nature Reserve
LPA Local Planning Authority
LQA Land Quality Assessment
LVIA Landscape and Visual Impact Assessment
mAOD metres above ordnance datum
MARLIN Marine Life Information Network
MAGIC Multi-Agency Geographical Information for the Countryside
MCAA Marine and Coastal Access Act 2009
MCA Maritime and Coastguard Agency
MCZ Marine Conservation Zone
MMO Marine Management Organisation
MNCR Marine Nature Conservation Review
MOB Main Operating Base
MOD Ministry of Defence
MPS UK Marine Policy Statement MSA Merchant Shipping Act 1995 NBN National Biodiversity Network NDT Non-Destructive Testing NE Natural England NERC Natural Environment and Rural Communities Act 2006 NHL National Heritage List NNR National Nature Reserve Noise Sound which a listener does not wish to hear. NPPF National Planning Policy Framework 2012
NPSE Noise Policy Statement for England
NTS Non-Technical Summary
OD Ordnance Datum OFD Oil Fuel Depot
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OIC Office In Charge
OPA Oil & Pipelines Agency
OS Ordnance Survey
OWS Oil Water Separator
PAH Polycyclic aromatic hydrocarbons
PCB Polychlorinated biphenyls PCSR Pre-Construction Safety Report
PEL Probable Effect Levels
PMRA Protection of Military Remains Act 1986
POSR Pre-Operation Safety Report
PPG5 Pollution Prevention Guidelines 5
PPS Planning Policy Statement
PRO Plymouth records Office
PRoW Public Rights of Way
PWA Protection of Wrecks Act 1973
QHM Queen’s Harbour Master
Rating Level (LAr,Tr) The noise level of an industrial noise source which includes an adjustment for the character of the noise. Used in BS 4142
RBMP River Basin Management Plan
RFA Royal Fleet Auxiliary
ROV Remote Operated Vehicles
Rw The weighted sound reduction index is a laboratory measurement of the sound insulating properties of a building material or building element.
SA Sustainability Appraisal
SAC Special Area of Conservation
SCADA Supervisory Control and Data Acquisition
SLR single lens reflex
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Sound A fluctuation of air pressure which is propagated as a wave through air.
Sound Level Meter An instrument consisting of a microphone, amplifier and indicating device, having a declared performance and designed to measure sound pressure levels.
Sound Pressure Level The fluctuations in air pressure, from the steady atmospheric pressure, created by sound, when measured on the decibel scale.
SPA Special Protection Area
SSSI Site of Special Scientific Interest
Sullage Sullage is an oily water waste product which is removed from ships and stored on site at the tank farm prior to removal for processing by a licenced contractor.
TBT Tributyltin
TECF Tamar Estuaries Consultative Forum
TEL threshold effect levels
THC Total Hydrocarbon Content
TPH Total petroleum hydrocarbons TSHD Trailing Suction Hopper Dredger UKHO UK Hydrographic Office
URD User Requirements Document
WAC Waste Acceptance Criteria
WeBS Wetland Bird Survey
WFD Water Framework Directive
WML Weston Mill Lake
ZoI Zone of Influence
ZTV Zone of Theoretical Visibility
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REFERENCES
Chapter One
1-1 The Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Fora
1-2 The EC Directive on the Conservation of Wild Birds (791409/EEC)
1-3 Marine and Coastal Access Act 2009
1-4 Tamar Estuaries Management Plan 2013 to 2018 (Tamar Estuaries Consultative Forum, 2012)
1-5 Town and Country Planning Act 1990 (as amended)
1-6 Department for Communities and Local Government, 2011. Town and Country Planning (Environmental Impact Assessment) Regulations 2011
1-7 Marine Works (Environmental Impact Assessment) Regulations 2007 (as amended)
1-8 EC Directive 2011/92/EU
1-9 Department for Communities and Local Government, March 2012, National Planning Policy Framework
1-10 Institute of Environmental Management and Assessment, 2004. Guidelines for Environmental Impact Assessment
Chapter Two
2-1 Control of Major Accidents and Hazards Regulations 1999
2-2 Existing Westminster Dredging Marine Licence
2-3 Westminster Dredging Marine Licence Application on public register
2-4 The Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Fora
2-5 Natura 2000 baseline document prepared for the MOD at Devonport Naval Base (2011)
2-6 Hyder Consulting Ltd (2010) Assessment Study
2-7 Department for Communities and Local Government, March 2012, National Planning Policy Framework
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2-8 Department for Communities and Local Government,2009, Planning Policy Statement 25 Development and Flood Risk Practice Guide
2-9 McMillan. A, Batstone. C, Worth. D, Tawn. J, Horsburgh. K, Lawless. M (2011). Coastal flood boundary conditions for UK mainland and islands. Bristol: Environment Agency
2-10 Initial Options Appraisal Report dated 15 January 2010
Chapter Three
3-1 The Town and Country Planning (Development Management Procedure) (England) (Amendment) Order 2013 3-2 Cornwall Council, Statement of Community Involvement, December 2011, available: 3-3 http://www.cornwall.gov.uk/media/3635991/SCI-as-Amended-220612.pdf
Town and Country Planning EIA Regulations
3-4 Marine Works EIA Regulations
3.5 Town and Country Planning Act 1990 (as amended)
3.6 Marine and Coastal Access Act 2009
3-7 Council Directive (2008/1/EC) Integrated Pollution Prevention & Control
3-8 Environmental Permitting (England and Wales) Regulations 2010
3-9 Council Directive ( 2000/60/EC) Water Framework Directive
3-10 The Water Environment (Water Framework Directive) (England and Wales) Regulations 2003
3-11 The Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Fauna and Fora
3-12 Conservation of Habitats and Species Regulations 2010. Her Majesty’s Stationary Office
3-13 Water Resources Act 1991
3-14 Fire Services Act 1947
3-15 Directive 2009/147/EC on the Conservation of Wild Birds for rare, vulnerable and regularly occurring migratory bird species and internationally important wetlands
Chapter Four
None
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Chapter Five
5-1 Contaminated Land Report 11. Model Procedures for the Management of Land Contamination. Defra/Environment Agency. September 2004. 5-2 Baseline Document for Maintenance Dredging in Plymouth Sound and Estuaries European Marine Site. Black and Veatch for DIO. August 2010 Revised March 2011 5-3 1:50,000 series geology map (Drift Edition) Sheet 348 Plymouth. British Geological Survey.
5-4 Soil Mechanics Logs Boreholes BHF, BHG, BHH, BHJ, BHK. 2004 5-5 Site Investigation Report in Support of Waste Management Licence Surrender. Environmental Science Group (ESG) for Defence Equipment and Support (DE&S) May 2008. ESG/08/011 5-6 OFD Thanckes, Torpoint Land Quality Assessment. SKM Enviros for Defence Infrastructure Organisation. DIO Project Number: Z9L1285Y09 Commission DE31/7115-1. Draft v2 April 2013 5-7 Industry Profile for Dockyards and Dockland. Department of the Environment. 1995 5-8 Environmental Monitoring for Radioactivity Around Devonport Royal Dockyard. Annual Report 2011. Babcock. 5-9 Technical Annex 1 of OSPAR Guidelines for the Management of Dredged Material (Reference number: 2009/4) OSPAR Commission 5.10 A desk study to assess the impact of dredging activity on the Tamar Estuary. PML Applications Ltd. January 2004 5-11 Tamar Estuaries Management Plan 2013 to 2018 (Tamar Estuaries Consultative Forum, 2012) 5-12 Marine Management Organisation (MMO) website accessed September 2013 http://www.marinemanagement.org.uk/licensing/how/sample_analysis.htm 5-13 Canadian Council of Ministers of the Environment (CCME) Canadian Environmental Quality Guidelines. http://ceqg-rcqe.ccme.ca/ Website accessed 06/09/13
5-14 Construction Industry Research & Information Association (CIRIA) C650 – Environmental Good Practice on Site, 2nd Ed. CIRIA. 2005
5-15 CIRIA C532 – Control of Water Pollution from Construction Sites (CIRIA, 2001)
Design Manual for Roads and Bridges (DMRB) - Volume 11, Section 3, Part 10 Road 5-16 Drainage and the Water Environment: HD 45/09. (Highways Agency, 2009)
5.17 Environment Agency, Pollution Prevention Guidelines No’s 1, 2, 3, 5, 6, 8 and 18
(Environment Agency, various publication dates) 5-18 Environment Agency. Soil Guideline Values and Toxicology Reports (2008) 5-19 Land Quality Management (LQM)/ Chartered Institute Environmental Health (CIEH) Generic Assessment Criteria for Human Health Risk Assessment. 2nd Edition. Land Quality
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Press 2009.
Chapter Six 6-1 Institute of Ecology and Environmental Management’s (IEEM) Guidelines for Ecological Impact Assessment (2006) (‘the IEEM Guidelines’) 6-2 Handbook for Phase 1 habitat survey: a technique for environmental audit, Joint Nature Conservation Committee, 2010 6-3 New Flora of the British Isles (2nd edition) Stace, C, 1997 6-4 Guidelines for the Conduct of Benthic Studies at Marine Aggregate Extraction Sites (2nd Edition). Marine Aggregate Levy Sustainability Fund. Pp. 80. Ware, S. J. and Kenny, A. J., 2011. 6-5 Marine Nature Conservation Review: rational and methods. Peterborough, Joint Nature Conservation Committee. Pp. 167. Hiscock, K., ed. 1996 6-6 Marine Monitoring Handbook. Joint Nature Conservation Committee. http://jncc.defra.gov.uk/page-2430. Accessed June 2013. Davies, J. et al., 2001 6-7 The Marine Habitat Classification for Britain and Ireland Version 04.05, Connor, D. W. et al, 2004, JNCC, Peterborough. ISBN 1 861 07561 8 (internet version). www.jncc.gov.uk/MarineHabitatClassification. Accessed June 2013 6-8 Plymouth Sound and Estuaries SAC Natura 2000 data form, JNCC, 27/07/11
6-9 IUCN Red List of Threatened Species, accessed via http://www.iucnredlist.org/search 6-10 Cornwall Wildlife Trust Seaquest Netsafe Project - Final Report 2012, Cornwall Wildlife Trust, 2012 6-11 St John’s Lake SSSI Condition of SSSI Units accessed online at www.sssi.naturalengland.org.uk, August 2013. 6-12 Thanckes Oil Fuel Depot, Devonport – Underwater Noise Impact during New Jetty Construction, Subacoustech Environmental, March 2014 (Report no E455R0305) 6-13 North Sea Fish and Fisheries, CEFAS, August 2001. 6-14 A desk study to assess the impact of dredging activity on the Tamar Estuary, PML Applications Ltd, 2004 6-15 Baseline Document for Maintenance Dredging in Plymouth Sound and Estuaries European Marine Site, Defence Estates, August 2010, revised March 2011 6-16 European Site Conservation Objectives for Tamar Estuaries Complex Special Protection Area Site Code: UK9010141, Natural England, undated. 6-17 Construction and Waterfowl: Defining Sensitivity, Response, Impacts and Guidance. Report to Humber INCA. Cutts, N; Phelps, A; Burdon, D. Institute of Estuarine and Coastal Studies, University of Hull. 2008. 6-18 Environmental impacts resulting from disposal of dredged material at the Rame Head disposal site, S.W. England: An analysis of existing data and implications for environmental management. Cefas Contract BA004. Cefas (2005). 6-19 Wave and Tidal Consenting Position Paper Series: Impacts on Fish and Shellfish Ecology, Natural Environment Research Council, October 2013.
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6-20 Likely sensitivity of bottlenose dolphins to pile-driving noise, J.A. David MCIWEM, Water and Environment Journal 2006. 6-21 Kinterbury Point (HMNB Devonport) FHSU Forward Operating Base MOD Decision Form 2223 (Stuart Otway, MOD, 2014). Chapter Seven 7-1 Institute for Archaeologists (IFA) 2012 Standard and Guidance for historic environment desk-based assessment
7-2 DETR, Environmental Impact Assessment: A Guide to Procedures , 2000
7-3 Department for Transport, Design Manual for Roads and Bridges (DMRB), Volume 11. Highways Agency document 208/07, 1993
7-4 English Heritage, Conservation Principles: policies and guidance for the sustainable management of the historic environment, 2008
7-5 Somerset County Council, South West Archaeological Research Framework , 2008.
Chapter Eight 8-1 Noise and Statutory Nuisance Act (1993). The Stationary Office 8-2 Environment Protection Act (1990) The Stationary Office 8-3 National Planning Policy Framework (2012), Department for Communities and Local Government, March 2012. 8-4 BS 4142:1997 ‘Method for rating of industrial noise affecting mixed residential and industrial areas’ BSI 8-5 BS 8233 Sound Insulation and Noise Reduction for Buildings – Code of Practice (2014) BSI 8-6 BS 5228:2009 ‘Noise and vibration control on construction and open sites’ – Part 1: Noise BSI
8-7 Control of Pollution Act (1974). The Stationary Office
Chapter Nine 9-1 European Landscape Convention, 2000, Council of Europe. 9-2 National Planning Policy Framework, 2012, Department for Communities and Local Government. 9-3 Caradon District Local Plan, 2007, Caradon District Council. 9-4 Guidelines for Landscape and Visual Impact Assessment: Third Edition, 2013, Landscape Institute and Institute of Environmental Management and Assessment. 9-5 Photography and Photomontage in Landscape and Visual Impact Assessment, 1999, Landscape Institute. 9-6 Countryside Character, 1999 (as amended), Countryside Agency/Natural England. 9-7 Cornwall and Isles of Scilly Landscape Character Study, 2008, Cornwall Council.
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