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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
Author
Various. Compiled Sarah
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 11th July 2002.
.
Page i
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
Page ii
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
3-J
Public Exhibition Feedback Form
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
6-A
Waste Classification
Bird Count Data
6-B Target Notes
6-C Tamar Report
6-D HRA Screening
6-E
6F
6G
Conservation objectives for Plymouth Sound and Estuaries European Marine Site
Migratory fish species present in the Tamar Estuary
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
6-6
Results of inter-tidal survey
Results of subtidal survey
Page 1
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
Hamoaze1 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.
Page 2
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].
Page 5
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).
Page 8
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
Page 9
the berth pocket is estimated to be approximately 19,000m3 (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 18,000m3 (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
(ha)
Berth Pocket (ha)
Approach Channel (ha)
Total Area
(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.
Page 10
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.
Page 11
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.
Page 12
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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Hyder Consulting (UK) Limited-2212959 Page 16
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.
Hyder Consulting (UK) Limited-2212959 Page 19
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)
applications. The EIA will be contained within the
ES will accompany the submission.
May 2015
Local Planning Authority (LPA) statutory
consultation period
28 days
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 -
Refurbish Approach
and Jetty Head
Option 4 causes less environment impact during
construction than some of the other new build
options, as the option makes use of large
elements of the existing footprint. No dredging is
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 4 has only limited
negative sustainability
impacts due to limited short-
term construction period.
Option 6 – Option 6 involves less environment impact Option 6 has only limited
Hyder Consulting (UK) Limited-2212959 Page 22
Refurbish Approach
and new build Jetty
Head north of
Existing
during construction than some of the other new
build options as the option makes use of the
existing approach footprint. Dredging is required
for this option as there is a need to extend the
dredged box northwards, although this is
mitigated because a similar area at the southern
end of the dredged box would be released from
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.
negative sustainability
impacts due to limited short-
term construction period,
although any dredging works
to the north of the existing
dredge box will require careful
consideration.
Option 7 – Build
new approach and
refurbish Jetty
Head
Option 7 involves greater environmental impact
during construction than some of the other new
refurbishment options, as the option requires a
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 7 has only limited negative sustainability impacts due to limited short-term construction period.
Option 8 –
Refurbish Approach
and Jetty Head and
provide new
floating platform
Option 8 involves less environment impact
during construction than some of the other new
build options, as the option makes use of the
existing Head footprint. A small amount of
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 8 has only limited
negative sustainability
impacts due to limited short-
term construction period.
Option 9 – New-
build Approach and
New-build Jetty
Head
Option 9 involves more environment impact
during construction than some of the other
refurbishment options, as the option requires a
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
new Approach and
floating Jetty Head
Option 14 involves a moderate environment
impact during construction as dredging of a new
dredge box is required. This however will be
offset by the abandonment of the dredge box to
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.
Option 14 has only limited
negative sustainability
impacts due to limited short-
term construction period.
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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
Hyder Consulting (UK) Limited-2212959 Page 24
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 37,000m3 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 24th 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
Hyder Consulting (UK) Limited-2212959 Page 25
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 17th 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 17th 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 24th 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 16th
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 4th 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 29th 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
impact
Very High High Medium Low Negligible
Major Very Large Large or Very
Large
Moderate or
Large
Slight or
Moderate
Slight
Moderate Large or Very
Large
Moderate or
Large
Moderate Slight Neutral or
Slight
Minor Moderate or
Large
Slight or
Moderate
Slight Neutral or
Slight
Neutral or
Slight
Negligible Slight Slight Neutral or
Slight
Neutral or
Slight
Neutral
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
Marine Management Organisation
Queens Harbour Master
The Duchy of Cornwall
Plymouth Council
Tamar Esturies Consultive Forum
Natural England
Environment Agency
Centre for Environment Fisheries and
Aquaculture (Cefas)
Cornwall Wildlife Trust (CWT)
British Trust for Ornithology (BTO)
Environmental Records Centre for
Cornwall and the Isles of Scilly
Cornwall Bird Watching &
Preservation Society
Oil and Pipeline Agency
The Crown Estate
Maritime and Coastguard Agency
(MCA)
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 15th November 2012 at Thanckes OFD, where the draft scoping report (issued on 6th
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 24th 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 14th November 2013 and 8th 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 23rd October 2013 at Torpoint Town Hall between
3pm and 7pm. A preview for the councillors took place the previous night (Tuesday 22nd
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 23rd October 2013, and what has
subsequently been displayed in local facilities following the exhibition.The website went live on
24th October with a two week deadline for receipt of all representations.
Parish Council meetings for Torpoint and Antony Parish Council were attended on 28th October
and 7th 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 9th 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
(1991/2003)
Not to allow controlled waters to be
significantly polluted.
It is a criminal offence to:
-knowingly permit any poisonous,
noxious or polluting matter or any
solid waste matter to enter any
controlled waters
- cause or knowingly permit any
trade effluent or sewage effluent to
be discharged into any controlled
waters without a consent, or outside
of the conditions of a consent.
Location of the jetty will include
consideration of pile lengths required,
which will be minimised and therefore
minimise soil arisings
Site investigation carried out to
establish potential for contamination to
occur
Principal Contractor to be informed of
hazards and risks and required to
produce and comply with mitigation
measures in method statements
Part 2A of the
Environmental
Protection Act (1990)
To protect controlled waters from
pollution by hazardous substances
in, on or under the land
Carry out a desk study to identify
potential sources of contamination
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
Policy Framework
(March 2012)
The document streamlines national
planning policy into a consolidated
set of priorities, with the core theme
being the delivery of sustainable
development and economic growth.
The Planning Practice Guidance
relating to land affected by
contamination refers to the
methodologies outlined in Part 2A of
the Environmental Protection Act
Carry out a desk study to identify
potential sources of contamination
which could have led to the
contamination of sediments in the river.
This will inform the site investigation
and any mitigation measures
considered necessary where a risk is
identified.
Consideration of waste reuse and
disposal options
Contaminated Land
Report (CLR) 11 ‘The
model procedures for
the Management of
Land Contamination’
To investigate and assess potential
risk to sensitive receptors (including
controlled waters, and flora and
fauna) from contaminated soil or
water
As above
The Water Framework
Directive (2000/60/EC)
Driver for water quality monitoring
which is required to establish a
framework for the protection of
inland surface waters, transitional
waters, coastal waters and
groundwater.
A WFD Screening Assessment has
been completed and is included in
Appendix 5-A
Marine and Coastal
Access Act 2009
Part 5 of this Act enables the
designation of MCZs. These are a
type of Marine Protected Area,
which protect a range of nationally
important marine wildlife, habitats,
geology and geomorphology. MCZs
exist alongside European marine
Sites, SSSIs and Ramsar sites to
form an ecologically coherent
network of marine protected areas.
The Tamar Estuary MCZ is located in
two separate areas including the upper
reaches of the Tamar and Lynher
estuaries. The development is
approximately 2km away from this
MCZ, at its closest point within the
Lynher estuary.
These potential receptors have been
considered in the assessment and
mitigation measures designed
accordingly.
Conservation of
Habitats and Species
Regulations 2010 (as
amended)’
The Regulations provide for the
protection of both Special Protection
Areas (SPAs) and Special Areas for
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.
Covered in detail within Chapter 6
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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 19,000m3.
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 18,000m3 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
high quality and
rarity on a
regional or
national scale
Surface
water:
EU designated salmonid/cyprinid fishery
Watercourse achieving Water Framework Directive (WFD) Class ‘High’
Site protected under EU or UK habitat legislation (Special Area of
Conservation, Special Protection Area, Site of Special Scientific Interest,
Ramsar site)
High Attribute has a
high quality and
rarity on a local
scale
Surface
water:
Watercourse achieving WFD Class ‘Good’
Major cyprinid fishery
Species protected under EU or UK habitat legislation
Medium Attribute has a
medium quality
and rarity on a
local scale
Surface
water:
Watercourse achieving WFD Class ‘Moderate’
Water feature that supports an abstraction for agricultural or industrial
use of between 50 and 499m3/day
Low Attribute has a
low quality and
rarity on a local
scale
Surface
water:
Watercourse that is not a fishery, achieving WFD Class ‘Poor’.
Supports an abstraction for agricultural or industrial use of < 50m3/day
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Table 5-39 Criteria for the Assessment of Overall Effect
Risk Term – See
Table 5-7
Importance/Sensitivity of Resource or Receptor
Very High High Medium Low Negligible
Very High Risk Very Large Large or Very
Large
Moderate or
Large
Slight or
Moderate
Slight
High Risk Large or Very
Large
Moderate or
Large
Moderate Slight Neutral or
Slight
Moderate Risk Moderate or
Large
Slight or
Moderate
Slight Neutral or
Slight
Neutral or
Slight
Low Risk Slight Slight Neutral or
Slight
Neutral or
Slight
Neutral
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.
Concentrations present likely to result in
“significant harm” as defined by Part 2A.
Substantial pollution of sensitive water
resources.
Medium Chronic damage to human health.
Concentrations present that could result in
significant harm.
Pollution of sensitive water resources or
small scale pollution of sensitive water
resources
Mild Slight short term health effects to humans.
Exposure to human
health unlikely to lead to significant harm.
Pollution to non-sensitive water resources
Minor Non-permanent health effects to human health
(easily prevented by means such as personal
protective clothing.)
Insubstantial pollution to non-sensitive
water resources
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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
part of the Marine Licence application.
Given the information available to date OSPAR
guidelines suggest sampling at 3 locations within the
proposed area to be dredged. Samples should be taken
at surface and every 1m for every meter to be dredged.
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.
Sampling was carried out by Fugro in the
course of the site investigation, and
samples submitted to the Cefas
laboratory in accordance with their
guidance. None of the samples analysed
were subject to ‘non-conformity’.
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
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.
Addressed in Section 5.5.1
Consideration is required of the potential impacts on
water quality and designated sites from contamination
within the sediment. If levels of contamination are
significant and potential impacts are identified suitable
methods and mitigation measures must be incorporated
for all stages of the project.
Addressed through intrusive investigation
and risk assessment outlined in this
Chapter
If an Environment Agency water discharge activity
permit is required the EIA will need to address the
requirements needed of the permit.
No particular requirement needed over
and above the standard permit conditions
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
analysis has been carried out to characterise
the dredge areas?
Based on the sediment/soil chemical analysis
results, do you concur that dredge arisings
are suitable for disposal at sea?
‘In summary, the results show that material from the sample
locations highlighted in yellow on the attached map are not
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
disposed of at sea. Sediments from the exclusion zones would
need to be disposed of on land or alternatively used. The material
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 16,000m3. 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
the proposed jetty. Are you content that the
information from the site investigation is
sufficient to characterise the pile arisings?
‘I am content that this area has been characterised sufficiently for
contamination purposes and given the small volume of material
(250m3) associated with the jetty structure and dolphins, no further
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
and Location
Potential / Likely Contaminants
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
(Ref. 5-6)
1920 100m W, upstream Metals, hydrocarbons
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
(current)
From Thanckes OFD for trade
effluent into the Tamar Estuary /
Hamoaze
Discharge point marked on the
existing jetty
~20m S, downstream
Discharge Consent
(current)
From Thanckes OFD for trade
effluent / site drainage into the
Tamar Estuary / Hamoaze
Discharge point marked at root of
existing jetty
~30m S, downstream
Discharge Consents
(discontinued)
From Thanckes OFD for trade
effluent / site drainage into the
Tamar Estuary / Hamoaze.
Surrendered 2010
Discharge points marked on
northern shore of OFD Thanckes.
~560-800m NW, upstream
Discharge Consents
(current and discontinued)
From Devonport Dockyard for trade
effluent, site drainage and sewage
into the Tamar Estuary / Hamoaze
Discharge points marked
throughout dockyard area.
~525-1000m E, up and downstream
Discharge Consents
(current and discontinued)
Held by South West Water for
treated sewage and trade effluent
and surface water
~530-1000m NW, SW, E, up and
downstream
Integrated Pollution
Prevention Control (IPPC)
permit
For Thanckes OFD for disposal of
waste oil >10 tonnes/day
Immediately west of site
Pollution incidents to
controlled waters
8 incidents recorded. 7 minor
incidents, 1 significant incident (at
Devonport Dockyard, ‘other
chemicals’, 1993). Oil, sewage,
other chemicals, algae. 1993-1995
listed
~525-910m, up and downstream
Landfill Former site at Torpoint. Multiple
waste types allowed. Closed prior to
1993.
~525m SW
Drain from landfill ~180m SW,
downstream
Waste management facility Thanckes OFD. Processing of
waste oil.
~150m W, upstream
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
Source
Potential
Receptor
Consequence Probability
(without mitigation)
Risk
Contaminated
Sediment
Metals,
hydrocarbons
Surface water
quality
Medium – the
surface water is
important for
ecological
receptors and is
assessed as
being of very
high sensitivity
Low likelihood – some elevated
concentrations have been found
but these are consistent with
levels in the surrounding area and
the proposed activity will be short
lived and is similar to that carried
out nearby.
Moderate/Low –
mitigation measures
should be considered
and are discussed below
Human Health Mild Low likelihood – the river is used
for water sports so that exposure
could occur but concentrations are
unlikely to be very high
Low – mitigation
measures to protect
surface water will also
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 18,000m3
(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 18,000m3 (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 250m3), 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 /
Permanent
Proposed Mitigation Measures Significance Rating
Construction Phase
Disturbance of sediment –
mobilisation of contaminants
through dissolution, and/or
additional sediment load
Temporary Take additional precautionary
measures while working in any
locations identified as having
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.
Slight negative
Deposition of sediment/soil arisings
on the river bed (in terms of water
quality)
Temporary Where there will be an ecological
effect then soil arisings will be
captured and disposed of off-site
Minimise pile soil arisings volume
Slight negative
Storage, transport and use of
contaminative substances on land
and over water – spill or leak to the
watercourse
Temporary Containment of hazardous
substances
Operational procedures including
monitoring and control
Emergency procedures and
equipment
Slight negative
Run off of silt laden or
contaminated surface water from
the land
Temporary Containment and removal of
soils
Operational procedures including
control of soil arisings
Slight negative
Decommission Phase (existing and proposed jetty)
Hazardous substances or foreign
materials entering the watercourse
Temporary Removal of hazardous
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
Slight negative
Removal of worn infrastructure Permanent Removal, reuse/recycle of the
old infrastructure which will
reduce the potential for a
pollution incident to occur
Large positive
Operational Phase
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Storage, transport and use of
contaminative substances on land
and over water – spill or leak to the
watercourse
Improved infrastructure will reduce
the risk of pollution events and
therefore have a positive effect
Permanent Containment of hazardous
substances
Operational procedures including
monitoring and control
Emergency procedures and
equipment
Moderate positive
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
Habitats and
Species Regulations
2010 (as amended)’
The Regulations provide for the
protection of both Special
Protection Areas (SPAs) and
Special Areas for 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.
Species which are relevant to this
application include the following:
• Atlantic salmon (Salmo salar) – Feature
of Dartmoor SAC.
• Allis shad (Alosa alosa) – Feature of
Plymouth Sound and Estuaries SAC.
• Twaite shad (Alosa falax) – present in
the Plymouth Sound and Estuaries SAC
but not at significant population levels.
• Sea lamprey (Petromyzon marinus) -
present in the Plymouth Sound and
Estuaries SAC but not at significant
population levels.
• Harbour porpoise (Phocoena phocoena)
– 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
Countryside Act
(1981) (as amended)
This Act is the
principle mechanism
for the legislative
protection of wildlife
in England.
The Act provides for the
designation of Sites of Special
Scientific Interest (SSSI), which
are selected as the best national
examples of habitat types, sites
with notable species and sites of
geological importance.
Schedules 1-4 of the Act deal
with the protection of wild birds.
Schedule 5 of the Act details
protection of other animal
species. Full protection is given
under Section 9 of the Act to
certain animals listed on
Schedule 5, including otters and
all species of bats. Partial
protection under Section 9 is
given to certain other species,
including all common species of
reptile. Badgers are listed on
Schedule 6 of the Act which
Eight SSSIs are located within 5km of the
proposed Development. A description of
SSSIs potentially affected by the proposed
Development is included in Section 6.4.
Potential ecological impacts are discussed in
Sections 6.6 and 6.7.
No terrestrial species protected by the Act
have been recorded within the terrestrial
areas of the Site, although habitats were
identified that were suitable to support such
species. These include common species of
reptiles and bats. It is considered likely that
otters use the intertidal habitats around the
Site.
Marine species listed on Schedule 5
recorded within the study area are as
follows:
• Harbour porpoise
• Bottlenose dolphin
• Risso’s dolphin
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outlaws certain methods of taking
or killing animals, where
necessary. Schedule 8 of the
Wildlife and Countryside Act
details protection for plants and
fungi.
Schedule 9 identifies non-native
species that should not be
introduced into, or spread in, the
wild.
• Common dolphin
• Allis and twaite shad
These marine species are also listed in the
Conservation of Habitats and Species
Regulations 2010 (as amended) and/or are
listed as a feature of the Plymouth Sound
and Estuaries SAC. A description of the
baseline conditions with regard to marine
mammals and migratory fish are included in
Section 6.4. Potential ecological impacts are
discussed in Sections 6.6 and 6.7.
Marine and Coastal
Access Act 2009
Part 5 of this Act enables the
designation of Marine
Conservation Zones (MCZs).
These are a type of Marine
Protected Area, which protect a
range of nationally important
marine wildlife, habitats, geology
and geomorphology. MCZs exist
alongside European marine
Sites, SSSIs and Ramsar sites to
form an ecologically coherent
network of marine protected
areas.
Two MCZs are considered within this
assessment; the Tamar Estuary MCZ and
the Whitsand and Looe Bay MCZ. The
Tamar Estuary MCZ supports migratory
European smelt (Osmerus eperlanus), which
breed within the Tamar Estuary and the
native oyster (Ostrea edulis). Native oysters
are also listed on the OPSAR List of
Threatened and/or Declining Species and
Habitats. Blue mussel (Mytilus edulis) beds
and European eel (Anguilla anguilla) are
also present.
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
Access to the
Countryside Act
1949
Local Nature
Reserves (LNRs) are
designated by Local
Authorities under
Section 21 of this act
as amended by
Schedule 11 of the
Natural Environment
and Rural
Communities
(NERC) Act 2006.
LNRs are places with a wildlife or
geological interest of local value
that are capable of being
managed with the conservation
of nature and/or the maintenance
of public access as priority
concerns.
Woodland Wood Valley LNR and Budshead
Wood LNR are located approximately 4.5
and 4.9km to the north-east of the Site
respectively, within the city of Plymouth.
NERC Act (2006) The NERC Act places a duty
upon public bodies to consider
conservation of biodiversity within
all of their actions. Sections 40
and 41 of this Act superseded
Section 74 of the Countryside
Rights of Way (CRoW) Act.
Section 41 lists flora, fauna and
Section 41 habitats and species recorded
within the study area include:
• Intertidal mudflats
• Seagrass beds
• Sublittoral sediments
• Allis shad
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habitats considered by the
Secretary of State to be of
Principal Importance for
conserving biodiversity in
England.
• Twaite shad
• Atlantic salmon
• Sea trout (Salmo trutta)
• 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
Convention for the
Protection of the
Marine Environment
of the North-East
Atlantic
OSPAR is the mechanism by
which fifteen Governments,
including the UK, of the western
coasts and catchments of
Europe, together with the
European Community, cooperate
to protect the marine
environment of the North-East
Atlantic. It begun in 1972 with the
Oslo Convention against
dumping. It was broadened to
cover land-based sources and
the offshore industry by the Paris
Convention of 1974. These two
conventions were unified, up-
dated and extended by the 1992
OSPAR Convention. An annex
on biodiversity and ecosystems
was adopted in 1998 to cover
non-polluting human activities
that can adversely affect the sea.
Habitats and species found in the vicinity of
the proposed Development and included on
the OSPAR List of Threatened and/or
Declining Species and Habitats are as
follows:
• Atlantic salmon
• European eel
• Allis and twaite shad
• Intertidal seagrass beds
• Native oyster
• Thornback ray (Raja clavata)
• Harbour porpoise
A description of the baseline conditions with
regard to these protected/notable species
and habitats are included in Section 6.4.
Potential ecological impacts are discussed in
Sections 6.6 and 6.7.
The Convention on
the Conservation of
European Wildlife
and Natural Habitats
(the Bern
Convention, 1979)
This Convention was adopted in
Bern, Switzerland in 1979, and
came into force in the UK in
1982. The principal aims of the
Convention are to ensure
conservation and protection of all
wild plant and animal species
and their natural habitats (listed
in Appendices I and II of the
Convention), to increase
cooperation between contracting
parties, and to afford special
protection to the most vulnerable
or threatened species (including
Species that have been recorded in the
vicinity of the proposed Development and
are listed on the Bern Convention are as
follows:
• Atlantic salmon
• Allis and twaite shad
• Sea and river lamprey
• Harbour porpoise
• Bottlenose dolphin
All of these species are also listed in the
Conservation of Habitats and Species
Regulations 2010 (as amended) . A
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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
Conservation of
Migratory Species of
Wild Animals (Bonn
Convention or CMS,
1979)
This Convention was adopted in
Bonn, Germany in 1979 and
came into force in the UK in1985.
Contracting Parties work together
to conserve migratory species
and their habitats by providing
strict protection for endangered
migratory species (listed in
Appendix 1 of the Convention),
concluding multilateral
agreements for the conservation
and management of migratory
species which require or would
benefit from international
cooperation (listed in Appendix 2
of the Convention), and by
undertaking co-operative
research activities.
Species that have been recorded in the
vicinity of the proposed Development and
listed on the Bonn Convention are as
follows:
• Harbour porpoise
• Bottlenose dolphin
These species are also listed on the
Conservation of Habitats and Species
Regulations 2010 (as amended) . A
description of the baseline conditions with
regard to marine mammals is included in
Section 4. Potential ecological impacts are
discussed in Sections 6.6 and 6.7.
National Planning
Policy Framework
(March 2012)
The document streamlines
national planning policy into a
consolidated set of priorities, with
the core theme being the delivery
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.
Opportunities for the conservation and
enhancement of areas for biodiversity within
the proposed Development are considered
within the assessment.
UK Marine Policy
Statement (MPS)
(March 2011)
The MPS is the
national framework
for taking decisions
affecting the marine
environment
Paragraph 2.3.2.1 states that
authorisation decisions that affect
the UK marine area must be
made in accordance with the
relevant marine policy
documents. In the case of the
South West Region, where the
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
Measures to avoid or mitigate any
potentially adverse impacts as a result of the
proposed Development are included within
the assessment.
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through location, mitigation and
consideration of reasonable
alternatives. Where significant
harm cannot be avoided,
appropriate compensatory
measures should be sought.
Biodiversity 2020: A
Strategy for
England’s Wildlife
and Ecosystem
Services
Its aim is to halt the loss of
biodiversity, support healthy well-
functioning ecosystems and
establish coherent ecological
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.
Measures to avoid or mitigate any potentially
adverse impacts as a result of the proposed
Development are included within the
assessment.
Caradon Local Plan
First Alteration
(August 2007)
Until a Local Plan for
Cornwall Council is
prepared, extant
planning policies
within each District of
the former County
Council will continue
to form the basis of
planning decisions.
The policies of most relevance to
this chapter are:
CL1: Nature Conservation,
where development that affects
sites of nature conservation
importance will not be permitted
without adequate mitigation or
the importance of the
development overrides the
significance of the site;
CL12: Sites of Special
Scientific Interest
(SSSI)/National Nature
Reserves (NNR), where
development that affects
SSSIs/NNRs will not be permitted
without adequate mitigation or
See also response to the Conservation of
Habitats and Species Regulations 2010 (as
amended).The Wildlife and Countryside Act
and the NERC Act (all above), with respect
to statutory designated sites and protected
species.
Four non-statutory designated sites of
County importance to nature conservation
known as County Wildlife Sites (CWS) are
found within 5km of the Site. These are:
• Lower Lynher Estuary;
• St John’s Lake;
• Tincombe Reserve;
• Clarrick and Pigshill Woods.
The potential effects on the Lower Lynher
Estuary and St John’s Lake are considered
in the context of the effects on the SAC and
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the importance of the
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
SPA.
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be permitted without mitigation.
Cornwall Biodiversity
Action Plan (BAP)
Volume 4: Priority
Projects, Cornwall
Biodiversity Initiative,
2011
The Cornwall Biodiversity
Initiative (CBI) produced the
latest volume of Cornwall’s Local
Biodiversity Action Plan in 2011.
This volume focuses on
landscape scale projects to
achieve habitat targets and
benefit a wider range of species
than previous species specific
recovery projects. In addition,
the CBI has published a new
Cornish BAP list which contains
43 habitats and 360 species.
Cornish Local Biodiversity Action Plan
(LBAP) habitats and species recorded within
the study area include intertidal mudflats,
seagrass beds, estuarine rocky habitats,
subtidal sands and gravels, otter, allis shad,
twaite shad, Atlantic salmon, sea trout,
garden tiger moth, mouse moth.
Where impacts have been identified on
species listed on the LBAP, mitigation has
been proposed including timing of works and
control of pollution.
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 26th and 27th 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 8th 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 26th 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 27th 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 18th 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 (0.45m2). 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 12th 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 surveys
Benthic surveys undertaken. Detailed results contained within Appendix 6-C
Impacts on marine ecology receptors from the release of contaminated sediments and smothering from increased suspended sediments
Detailed assessment of potential impacts on key ecological receptors
Assessment of habitats and species listed on OSPAR List of Threatened and Declining Species and Habitats
Detailed assessment of potential impacts on key ecological receptors
MMO confirmed that there was no need for a separate MCZ assessment report in a conversation on 25th September 2014
No separate MCZ assessment has been produced. Potential impacts on MCZs are considered within this Ecology chapter
NE Potential impacts on migratory fish through underwater vibration
Detailed assessment of potential impacts on migratory fish as a key ecological receptor, 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, SPA and SSSI features
Detailed assessment of potential impacts on key ecological receptors
Insufficient information provided to undertake a Test of Likely Significant Effect
HRA Screening Report provided in Appendix 6-D
EA Map and survey habitats under the development footprint
Intertidal and subtidal surveys undertaken. 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 carried out between December and March
See response above regarding piling. it is recommended that Dredging will take place between and March.
Proposals to protect, restore and enhance nature conservation
The overall purpose of the proposed Development is to upgrade and modernise an 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 26th 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
17th 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
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 from the Tamar Estuary Complex: 5 year (2006/7-10/11) autumn mean peak
High-tide Low-tide High-tide Low-tide
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.
Thanckes jetty
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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
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
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
17th 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
17th 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
Hyder Consulting (UK) Limited-2212959 Page 99
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.
Hyder Consulting (UK) Limited-2212959 Page 100
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.
Hyder Consulting (UK) Limited-2212959 Page 101
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.
Hyder Consulting (UK) Limited-2212959 Page 102
Figure 6-5 Results of inter-tidal survey
Hyder Consulting (UK) Limited-2212959 Page 103
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)
Hyd
er
Consultin
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) L
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Pag
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Tab
le 6
-5 R
esu
lts o
f M
ari
ne a
nd
In
tert
idal S
urv
eys
Bio
top
e N
am
e a
nd
C
od
e
Bio
top
e/S
pecie
s
Descri
pti
on
E
co
log
ical R
ecep
tor
Co
rresp
on
din
g
Desig
nati
on
s
Eco
log
ical V
alu
e
Eco
log
ical V
alu
e a
nd
Sco
pin
g D
ecis
ion
Sub-litto
ral m
ud in
vary
ing s
alin
ities
(estu
aries)
SS
.SM
u.S
MuV
S
Shallo
w s
ublit
tora
l m
uds,
ext
endin
g fro
m the e
xtre
me
low
er
shore
into
the s
ubtidal
in v
ariable
salin
ity
(estu
arine)
conditio
ns
Benth
ic
Subtidal M
ud (
variable
salin
ity)
SA
C h
abitat
Section 4
1 N
ER
C A
ct
2006
Dis
tric
t/B
oro
ugh
The h
isto
rical dre
dgin
g r
egim
e a
nd h
igh u
se
of th
e e
stu
ary
heavily
impact
s th
e s
ublit
tora
l sedim
ents
leavi
ng the S
ite im
poveri
shed a
nd
no s
ignific
ant num
bers
of im
port
ant speci
es
were
identified. N
evert
hele
ss, th
e im
pacts
on the s
ubtidal m
ud w
ill b
e c
onsid
ere
d in the
conte
xt o
f th
e I
nte
rnati
on
ally im
port
ant
SA
C.
Sub-litto
ral m
ixed
sedim
ent in
vary
ing
salin
ity
(estu
aries)
SS
.SM
x.S
MxV
S
Shallo
w s
ublit
tora
l m
ixed
sedim
ents
in e
stu
arine
conditi
ons,
often w
ith
surf
ace s
hells
or
sto
nes,
enablin
g the d
evelo
pm
ent
of
div
ers
e e
pifaunal
com
munitie
s a
s w
ell
as
infa
unal co
mm
unitie
s.
Benth
ic
Subtidal M
ud (
variable
salin
ity)
SA
C h
abitat
Section 4
1 N
ER
C A
ct
2006
Dis
tric
t/B
oro
ugh
As for
SS
.SM
u.S
MuV
S
Cre
pid
ula
forn
icata
and
Medio
mastu
s fr
agili
s in
variable
salin
ity
infr
alli
ttora
l m
ixed
sedim
ent
SS
.SM
x.S
MxV
S.C
reM
ed
Vari
able
salin
ity
mix
ed
sedim
ent chara
cte
rised b
y th
e s
lipper
limpet (C
repid
ula
fo
rnic
ata
) and the
poly
chaete
s (
Medio
mastu
s fr
agili
s)
and (
Aphelo
chaeta
m
arion
i).
Benth
ic
Subtidal M
ixed
Sedim
ent
(variable
salin
ity)
SA
C h
abitat
Section 4
1 N
ER
C A
ct
2006
Dis
tric
t/B
oro
ugh
As for
SS
.SM
u.S
MuV
S
Yello
w a
nd g
rey lic
hens
on s
upra
litto
ral ro
ck
LR
.FLR
.Lic
.YG
Vert
ical to
gently s
lopin
g
bedro
ck a
nd s
table
bould
ers
in
the s
upra
litto
ral (o
r spla
sh
zone)
of th
e m
ajo
rity
of
rocky
shore
s a
re t
ypic
ally
chara
cterised b
y a
div
ers
e
com
munity o
f yello
w a
nd
gre
y lic
hens
such a
s X
anth
oria p
arietin
a,
Calo
pla
ca m
arina,
Lecanora
atr
a a
nd R
am
alin
a s
pp..
Spla
sh Z
one E
stuarine
Rocky h
abitat
Section 4
1 N
ER
C A
ct
2006
LB
AP
Priority
Habitat
Parish/N
eig
hbourh
ood
The s
mall
are
a o
f ro
cky
habitat th
at
support
ed this
bio
tope w
as
deem
ed t
o b
e o
f only
Pari
sh
/Neig
hb
ou
rho
od
import
ance
due t
o it
s li
mited e
xtent
and its
com
posi
tion
com
prisin
g c
om
mon lic
hen s
pecie
s. In
additio
n, it
is c
onsi
dere
d h
ighly
unlik
ely
that
both
terr
estr
ial and m
arine c
onstr
uct
ion
work
s w
ill a
ffect th
is b
ioto
pe.
Verr
ucaria m
aura
on
Upper
litto
ral f
ringe b
edro
ck,
S
pla
sh Z
one E
stuarine
Section 4
1 N
ER
C A
ct
Parish/N
eig
hbourh
ood
As for
LR
.FLR
.Lic
.YG
Hyd
er
Consultin
g (
UK
) L
imited-2
212
95
9
Pag
e 1
05
Bio
top
e N
am
e a
nd
C
od
e
Bio
top
e/S
pecie
s
Descri
pti
on
E
co
log
ical R
ecep
tor
Co
rresp
on
din
g
Desig
nati
on
s
Eco
log
ical V
alu
e
Eco
log
ical V
alu
e a
nd
Sco
pin
g D
ecis
ion
very
exp
osed t
o v
ery
sheltere
d u
pper
litto
ral
frin
ge r
ock
LR
.FLR
.Lic
.Ver.
Ver
bould
ers
and s
table
cobble
s
on v
ery
exp
osed t
o v
ery
sheltere
d s
hore
s w
hic
h
have a
bla
nket covering o
f th
e b
lack
lichen V
err
ucaria
maura
. T
his
zone is
norm
ally
found b
elo
w the
yello
w/g
rey lic
hen z
one a
nd
there
is
not
alw
ays
a c
lear
transiti
on b
etw
een t
he t
wo.
rocky
habitat
2006
LB
AP
Priority
Habitat
Pelv
etia c
analic
ula
ta o
n
sheltere
d,
variable
salin
ity
litto
ral fr
inge r
ock
LR
.LLR
.FV
S.P
eIV
S
Low
er
litto
ral f
ringe b
edro
ck
or
stable
bould
ers
and
mix
ed s
ubst
rata
on v
ery
sheltere
d t
o e
xtre
mely
sheltere
d v
ariable
salin
ity
shore
s c
hara
cte
rised b
y a
dense c
over
of th
e w
rack
Pelv
etia c
anlic
ula
ta,
whic
h
oft
en o
verg
row
s a c
rust of
bla
ck
lichens V
err
uca
ria
maura
.
Inte
rtid
al
Estu
ari
ne r
ocky
habitat
Section 4
1 N
ER
C A
ct
2006
LB
AP
Priority
Habitat
Parish/N
eig
hbourh
ood
As for
LR
.FLR
.Lic
.YG
Fucus s
piralis
on
sheltere
d v
ariable
salin
ity
upper
eulit
tora
l ro
ck
LR
.LLR
.FV
S.F
spiV
S
Sheltere
d t
o e
xtre
mely
sheltere
d u
pper
eulit
tora
l bedro
ck o
r m
ixed s
ubstr
ata
(b
ould
ers
, la
rge c
obble
s o
r shells
on m
ud)
in v
ariable
salin
ity
conditi
ons
chara
cterised b
y a
band o
f th
e s
pir
al w
rack
Fucus
spira
lis.
Inte
rtid
al
Estu
ari
ne r
ocky
habitat
Section 4
1 N
ER
C A
ct
2006
LB
AP
Priority
Habitat
Parish/N
eig
hbourh
ood
As for
LR
.FLR
.Lic
.YG
Ascophyllu
m n
odosum
and F
ucus
vesic
ulu
s o
n
variable
salin
ity m
id
eulit
tora
l ro
ck
LR
.LLR
.FV
S.A
ScV
S
Very
sheltere
d to e
xtre
mely
sheltere
d m
id e
ulit
tora
l bedro
ck, bould
ers
or
cobble
s s
ubje
ct to
variable
salin
ity
chara
cterised b
y a
n
impoverished c
om
munity
dom
inate
d b
y the w
racks
Ascophyllu
m n
odosum
and
Fucus v
esic
ulo
sus.
Inte
rtid
al
Estu
ari
ne r
ocky
habitat
Section 4
1 N
ER
C A
ct
2006
LB
AP
Priority
Habitat
Parish/N
eig
hbourh
ood
This
habitat w
ithin
the inte
rtid
al re
gio
n w
as
impoverished b
ut connecte
d t
o s
imila
r habitat alo
ng the s
hore
line a
nd s
o w
as
giv
en
a v
alu
e o
f P
ari
sh
/Neig
hb
ou
rho
od
im
port
ance. T
his
recepto
r is
there
fore
not
consid
ere
d v
alu
able
enough f
or
any
sig
nific
ant im
pacts
to a
rise.
Hyd
er
Consultin
g (
UK
) L
imited-2
212
95
9
Pag
e 1
06
Bio
top
e N
am
e a
nd
C
od
e
Bio
top
e/S
pecie
s
Descri
pti
on
E
co
log
ical R
ecep
tor
Co
rresp
on
din
g
Desig
nati
on
s
Eco
log
ical V
alu
e
Eco
log
ical V
alu
e a
nd
Sco
pin
g D
ecis
ion
Ephem
era
l gre
en a
nd
red s
eaw
eeds o
n
variable
salin
ity a
nd/o
r dis
turb
ed e
ulit
tora
l m
ixed
substr
ata
LR
.FLR
.Eph.E
phX
Eulit
tora
l mix
ed s
ubst
rata
(p
ebble
s a
nd c
obble
s
overl
ying s
and o
r m
ud)
that
are
subje
ct to
variations
in
salin
ity
and/o
r si
ltation,
chara
cterised b
y d
ense
bla
nkets
of
ephem
era
l gre
en a
nd r
ed s
eaw
eeds.
T
he m
ain
specie
s p
resent
are
Ente
rom
orp
ha
inte
stin
alis
, U
lva lactu
ca
and P
orp
hra
spp..
Inte
rtid
al
Mix
ed S
edim
ent
Section 4
1 N
ER
C A
ct
2006
Sheltere
d M
uddy
Gra
vels
.
Parish/N
eig
hbourh
ood
This
habitat w
ithin
the inte
rtid
al re
gio
n w
as
giv
en a
valu
e o
f P
ari
sh
/Neig
hb
ou
rho
od
im
port
ance a
s it pro
vides s
om
e d
ivers
ity
am
ong a
fucoid
dom
inate
d a
rea. A
n
ext
rem
ely
sm
all
are
a o
f th
is b
ioto
pe w
ill b
e
dir
ectly
under
the footp
rint of th
e
develo
pm
ent (<
40m
2)
but th
e r
ecepto
r is
not
consid
ere
d v
alu
able
enough f
or
any
sig
nific
ant im
pacts
to a
rise.
Seagra
ss b
eds o
n li
ttora
l sedim
ents
LS
.LM
p.L
Sgr
Mid
and u
pper
shore
wave-
sheltere
d m
uddy fin
e s
and
or
sandy
mud w
ith n
arr
ow
-le
afe
d e
el gra
ss
Zost
era
noltii
at
an a
bundance o
f fr
equent
or
above.
Inte
rtid
al seagra
ss
beds
(mudflats
)
As S
eagra
ss
Beds:
OS
PA
R L
ist of
Thre
ate
ned a
nd/o
r D
eclin
ing S
peci
es a
nd
Habitats
Section 4
1 N
ER
C A
ct
Corn
wall
BA
P P
riority
H
abitat
As M
udflats
:
SA
C/H
abitats
Directive
Annex
I H
abitat
Section 4
1 N
ER
C A
ct
Corn
wall
BA
P P
riority
H
abitat
County
S
eagra
ss B
eds a
re lis
ted a
s a h
abitat of
pri
ncip
al i
mport
ance o
n S
ection 4
1 o
f th
e
NE
RC
Act and the C
orn
wall
BA
P a
nd h
as
als
o b
een lis
ted b
y O
SP
AR
. T
he s
eagra
ss
beds a
dja
cent to
the s
hore
, w
ithin
the s
ite,
are
desig
nate
d a
s a
n A
GS
V. A
t th
e
pro
posed D
evelo
pm
ent si
te the s
eagra
ss
was found t
o b
e locally
abundant, b
ut
was
not a s
wath
e o
f pla
nts
. H
ow
ever,
the
seagra
ss a
t th
e S
ite w
as lin
ked t
o furt
her
seagra
ss h
abitat
either
sid
e o
f Y
onderb
err
y P
oin
t th
at
appeare
d t
o b
e o
f good q
ualit
y.
Inte
rtid
al m
udflats
are
lis
ted a
s a
habitat of
pri
ncip
al i
mport
ance o
n S
ection 4
1 o
f th
e
NE
RC
Act and the C
orn
wall
BA
P.
The
mudflats
adja
cent to
the s
hore
, w
ithin
the
site,
are
desig
nate
d a
s a
n A
GS
V. W
hils
t th
is
habitat is
outs
ide o
f th
e S
AC
boundary
, ‘m
udflats
and s
andflats
not covere
d b
y seaw
ate
r at lo
w tid
e’ i
s a
qualif
yin
g featu
re o
f th
e a
dja
cent
Ply
mouth
Sound a
nd E
stuaries
SA
C.
Although t
he m
udflat does n
ot show
exc
eptional div
ers
ity,
pro
bably
due t
o t
he
natu
re o
f th
e land u
se s
urr
oundin
g the S
ite, it
is f
unctionally
lin
ked to the S
AC
habitats
and
main
tain
s c
onnectivity
betw
een t
he m
udflats
acro
ss the w
ider
are
a.
Hyd
er
Consultin
g (
UK
) L
imited-2
212
95
9
Pag
e 1
07
Bio
top
e N
am
e a
nd
C
od
e
Bio
top
e/S
pecie
s
Descri
pti
on
E
co
log
ical R
ecep
tor
Co
rresp
on
din
g
Desig
nati
on
s
Eco
log
ical V
alu
e
Eco
log
ical V
alu
e a
nd
Sco
pin
g D
ecis
ion
Giv
en t
he a
bundance o
f seagra
ss
and the
low
div
ers
ity o
f th
e m
udflats
, th
is b
ioto
pe is
giv
en a
valu
e o
f C
ou
nty
im
port
ance. T
he
bio
tope w
ill b
e u
nder
the footp
rint
of th
e
develo
pm
ent in
additi
on t
o p
oss
ibly
bein
g
aff
ecte
d b
y s
edim
ent depositio
n.
Ste
rnaspis
scuta
ta
This
specie
s is
a s
tout
burr
ow
ing p
oly
chaete
worm
, w
hitis
h-g
rey in c
olo
ur,
with a
le
ath
ery
text
ure
.
Ste
rnaspis
scuta
ta
inhabits s
andy
and
muddy
substr
ata
, w
here
it
burr
ow
s head-
dow
n, exp
osin
g the
gill
s on its
poste
rior
end.
P
arish/N
eib
ourh
ood
This
indiv
idual w
as
found in g
rab s
am
ple
num
ber
3 n
ear
the p
ositi
on o
f th
e n
ew
jett
y.
Although it has
no d
esig
nation, it
is a
rare
specie
s o
nly
record
ed a
long t
he s
outh
D
evon c
oast
, fr
om
Ply
mouth
Sound to
Ottert
on P
oin
t, a
nd in D
ors
et at P
ort
land
Harb
our.
As
only
one indiv
idual w
as
found, it
is n
ot consid
ere
d v
alu
able
enough f
or
any
sig
nific
ant im
pacts
to a
rise. T
he e
ffects
on it
s habitat w
ill b
e a
ssessed in the c
onte
xt o
f th
e
SA
C.
Native o
yst
er
N
ative o
yst
er
is a
biv
alv
e
mollu
sc that has
an o
val or
pear-
shaped s
hell
with a
ro
ugh, scaly
surf
ace. T
he
two h
alv
es (
valv
es)
of th
e
shell
are
diffe
rent
shapes.
Ost
rea e
dulis
is
associ
ate
d w
ith h
ighly
pro
duct
ive e
stu
arine
and s
hallo
w c
oast
al
wate
r habitats
on firm
bottom
s o
f m
ud, ro
cks,
m
uddy
sand, m
uddy
gra
vel w
ith s
hells
and
hard
silt
.
OS
PA
R L
ist of
Thre
ate
ned a
nd/o
r D
eclin
ing S
peci
es a
nd
Habitats
Section 4
1 N
ER
C A
ct
2006
Corn
wall
BA
P p
riority
specie
s
Neglig
ible
O
nly
one liv
e o
yst
er
was found in g
rab
sam
ple
num
ber
6. O
yste
rs a
re u
sually
clu
stere
d in g
roups
asso
ciate
d w
ith h
ighly
pro
duct
ive e
stu
arine a
nd s
hallo
w c
oast
al
wate
r habitats
. T
hey c
an b
e found o
n firm
m
ud, ro
ck,
muddy
sand, m
uddy
gra
vel w
ith
shells
and h
ard
silt
. O
ne o
f th
e m
ost
suitable
sett
lem
ent subst
rate
s is
natu
ral oyst
er
shell.
H
ence t
hey a
re u
sually
found w
ith o
ther
oyste
rs. It is
lik
ely
that th
is indiv
idual
deta
ched f
rom
the o
yst
er
beds u
pstr
eam
and
is u
nlik
ely
to form
part
of
a s
ignific
ant gro
up,
thus
it w
ill n
ot be c
onsi
dere
d f
urt
her
in the
impact
assessm
ent.
Thorn
back R
ay
A s
hort
-snoute
d r
ay w
ith
typic
al dia
mond s
hape a
nd
sharp
ly a
ngle
d p
ecto
ral fins
appro
achin
g 9
0 d
egre
es.
The c
olo
ur
is v
ariable
, usually
a m
ottle
d, blo
tchy
bro
wn to g
rey, w
ith
num
ero
us
small
dark
spots
Thorn
back r
ay
frequents
a w
ide
variety
of gro
unds
from
mud, sand,
shin
gle
and g
ravel. It
is less fre
quently
record
ed o
n c
oars
er
sedim
ent ty
pes. T
hey
OS
PA
R L
ist of
Thre
ate
ned a
nd/o
r D
eclin
ing S
peci
es
Parish/N
eig
hbourh
ood
Only
one indiv
idual w
as
seen o
n v
ideo
transect
num
ber
4. A
s only
one indiv
idual
was found, it is
not consi
dere
d v
alu
able
enough f
or
any s
ignifi
cant im
pact
s to
arise.
This
is a
hig
hly
mobile
specie
s a
nd there
fore
im
pact
s a
re c
onsid
ere
d u
nlik
ely
.
Hyd
er
Consultin
g (
UK
) L
imited-2
212
95
9
Pag
e 1
08
Bio
top
e N
am
e a
nd
C
od
e
Bio
top
e/S
pecie
s
Descri
pti
on
E
co
log
ical R
ecep
tor
Co
rresp
on
din
g
Desig
nati
on
s
Eco
log
ical V
alu
e
Eco
log
ical V
alu
e a
nd
Sco
pin
g D
ecis
ion
and y
ello
wis
h p
atc
hes.
Dors
ally
the b
ody
is c
overe
d
with c
oars
e p
rickle
s, w
hic
h
are
pre
sent
from
hatc
hin
g.
In a
dditi
on, la
rge,
back
ward
poin
ting thorn
s (c
alle
d
buckle
rs)
are
sca
ttere
d o
ver
the d
ors
al surf
ace,
each o
f w
hic
h h
as
a t
hic
k button-lik
e
base.
are
als
o found o
n
patc
hes o
f sedim
ent
am
ong r
ocky
outc
rops
and b
ould
ers
. It m
ay
be f
ound t
o a
depth
of
300m
but m
ost
com
mon b
etw
een 1
0 –
60m
. A
lthough m
ain
ly
a n
on-m
igra
tory
specie
s, th
e fis
h o
ften
moves c
lose inshore
during the s
pring.
Hyder Consulting (UK) Limited-2212959 Page 109
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 Plymouth Sound and Estuaries SAC.
April – July (peak May/June)
Atlantic salmon Qualifying feature of Dartmoor SAC.
April – December (peak June/July/August/September/October)
Sea trout Section 41 of the NERC Act 2006 species of Principal Importance
March – December (peak May/June/July)
Salmon & Sea trout smolts
Section 41 of the NERC Act 2006 species of Principal Importance
April – June
Sea trout kelts Section 41 of the NERC Act 2006 species of Principal Importance
November – December (downstream migration)
European smelt
Reason for designation of Tamar Estuary MCZ
February – April
Eels (juvenile) ‘Critically endangered’ on the IUCN Red Data List
March – May (Sea to freshwater)
Eels (adult) ‘Critically endangered’ on the IUCN Red Data List
Autumn months (downstream migration)
River and sea lamprey
Listed as being present in the Plymouth Sound and Estuaries SAC but not at significant population levels
April - July
Twaite shad Listed as being present in the Plymouth Sound and Estuaries SAC but not at significant population levels
April – July (peak May/June)
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
Hyder Consulting (UK) Limited-2212959 Page 110
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).
Hyder Consulting (UK) Limited-2212959 Page 111
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
species/habitats
Nature
Conservation
Value
Potentially significant
effect
Key Ecological Receptors
Subtidal mudflats
associated with
Plymouth Sound and
Estuaries SAC
Varied infaunal
communities,
particularly bivalves and
other invertebrates.
International.
However, the subtidal
mud and mixed
sediments surveyed
during the marine
survey were
impoverished and no
significant numbers of
important species
were identified. The
habitats within the
SAC surveyed during
the marine survey
were considered to
be of District/Borough
value.
Direct loss of SAC habitat
(subtidal mud and mixed
sediments) during
construction (piling and
dredging) and through
capital and maintenance
dredging.
Piling, capital dredging
and maintenance dredging
operations causing an
increase in suspended
sediment and sediment
deposition leading to
smothering of habitats.
Bird species associated
with the Tamar
Estuaries Complex SPA
Bird species associated
with the Lynher Estuary
SSSI, St John’s Lake
SSSI
The bird species for
which the Tamar
Estuaries Complex
has been designated
an SPA are included
within this receptor
(little egret). In
addition there are a
number of other
wader and wildfowl
species mentioned
within the SSSI
citations. These have
also been included
within this receptor.
International for
SPA qualifying bird
species
National importance
for SSSI habitats and
wintering wader and
wildfowl species
Disturbance to wintering
species throughout
construction works (in
particular piling works).
Capital and maintenance
dredging operations have
the potential to indirectly
affect intertidal habitats
e.g. by an increase in
suspended sediment and
sediment deposition
causing smothering of
habitats and a loss of
feeding resource.
Hyder Consulting (UK) Limited-2212959 Page 112
Ecological Receptor Associated
species/habitats
Nature
Conservation
Value
Potentially significant
effect
Intertidal mudflats and
subtidal sediments.
Habitats and associated
species within Whitsand
and Looe Bay MCZ
Intertidal sand and
coarse sediments,
subtidal sand and
coarse sediments, rocky
habitats, seagrass beds.
Ocean quahog, pink
sea-fan, sea-fan
anemone, stalked
jellyfish.
National Deposition of dredged
material at Rame Head
disposal site has the
potential to cause an
increase in suspended
sediment and sediment
deposition leading to
smothering of habitats.
Seagrass beds Wintering and on-
passage birds, intertidal
mudflats
County Direct loss of habitat under
piling.
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:
Atlantic salmon,
qualifying feature of
Dartmoor SAC
Allis shad, qualifying
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
Subtidal habitats International Disturbance/risk of
mortality of migratory fish
during construction (piling
and dredging operations)
and operation
(maintenance dredging).
Hyder Consulting (UK) Limited-2212959 Page 113
Ecological Receptor Associated
species/habitats
Nature
Conservation
Value
Potentially significant
effect
lamprey and sea
lamprey, present in
Plymouth Sound and
Estuaries SAC but not
at significant population
levels
Other fish species:
bass, lemon sole, sole,
sprat, monkfish,
mackerel, spurdog,
whiting
Subtidal habitats Regional Disturbance/risk of
mortality of fish during
construction (piling and
dredging operations) and
operation (maintenance
dredging).
Marine mammals,
including bottlenose
dolphin, harbour
porpoise and grey seal,
which are present within
the Plymouth Sound
and Estuaries SAC but
not at qualifying
population levels.
Subtidal habitats District/Borough Disturbance due to piling
and dredging works
(construction phase) and
from maintenance
dredging.
Ecological Receptor Associated
species/habitats
Nature
Conservation
Value
Effect requiring
mitigation
Other ecological receptors requiring mitigation on the basis of legislation
Otter Intertidal mudflats Parish/
Neighbourhood
Disturbance to any
commuting otters during
construction.
Breeding birds Trees, scrub and
woodland
Parish/
Neighbourhood
Damage or destruction of
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
species/habitats
Nature
Conservation
Value
Reason receptor
scoped out
Ecological receptors not considered further
Habitats associated with Sandbanks covered by International No direct or indirect effects
Hyder Consulting (UK) Limited-2212959 Page 114
Plymouth Sound and
Estuaries SAC
including habitats
associated with Lynher
Estuary SSSI, and St
John’s Lake SSSI
sea water, estuaries,
shallow inlets and bays,
reefs, Atlantic salt
meadows, mudflats and
sandflats not covered by
seawater at low tide.
predicted on these
habitats.
Tamar Estuaries
Complex SPA
Avocet International No direct or indirect effects
predicted on avocet.
Dartmoor SAC (Atlantic
salmon considered
under migratory fish,
otters considered on
basis of legal protection)
Northern Atlantic wet
heaths with Cross-
leaved heath, European
Dry heaths, blanket
bogs and sessile oak
woods. Southern
damselfly
International No direct or indirect effects
predicted on these
habitats and species.
Tamar-Tavy SSSI Wintering and on-
passage birds, intertidal
mudflats
National No direct or indirect effects
predicted.
Plymouth Sound Shores
and Cliffs SSSI
Geological interest National No direct or indirect effects
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
Point SSSI
Geological interest National No direct or indirect effects
predicted.
Tamar Estuary MCZ
European smelt and
European eel part of the
migratory fish receptor
Intertidal biogenic reefs,
intertidal coarse
sediment, native oyster
and blue mussel
National No direct or indirect effects
predicted.
Woodland Wood Valley
LNR
Woodland, hedgerows,
meadow, stream
District/Borough No direct or indirect effects
predicted.
Budshead Wood LNR Woodland, tidal creek District/Borough No direct or indirect effects
predicted.
Tincombe Reserve
CWS
Woodland County No direct or indirect effects
predicted.
Lower Lynher Estuary
CWS
Saltmarsh habitat County No direct or indirect effects
predicted.
Hyder Consulting (UK) Limited-2212959 Page 115
St John’s Lake CWS Saltmarsh habitat County No direct or indirect effects
predicted.
Clarrick and Pigshill
Woods CWS
Woodland County No direct or indirect effects
predicted.
Churchdown Farm
Community Nature
Reserve
Meadows Parish/
Neighbourhood
No direct or indirect effects
predicted.
Terrestrial plants and
habitats
Broadleaved woodland,
Scrub, amenity
grassland, ruderal
grassland, common
species of reptile,
amphibians and
invertebrates
Parish/Neighbourhoo
d for broadleaved
woodland, negligible
for remaining habitats
Receptor not sufficiently
valuable for impacts to
arise. The area of scrub
and ruderal grassland
habitat to be directly
affected by the proposed
Development is negligible.
Terrestrial invertebrates Scrub, woodland,
amenity grassland
Negligible Receptor not sufficiently
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
storage tanks, scrub,
woodland, amenity
grassland
Negligible Receptor not sufficiently
valuable for impacts to
arise.
Reptiles Scrub, woodland,
concrete tanks and
areas of bare ground
Parish/
Neighbourhood
Receptor not sufficiently
valuable for impacts to
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,
amenity grassland,
ruderal grassland
Parish/
Neighbourhood
Receptor not sufficiently
valuable for impacts to
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,
amenity grassland
Negligible No direct or indirect effects
predicted as considered to
be absent from the Site.
Hyder Consulting (UK) Limited-2212959 Page 116
Intertidal mixed
sediment
Seaweed
Parish/
Neighbourhood
Receptor not sufficiently
valuable for impacts to
arise. The area of intertidal
mixed sediment to be
directly affected by the
proposed Development is
negligible.
Intertidal estuarine rocky
habitat
Intertidal Seagrass
beds, intertidal mixed
sediment
Parish/
Neighbourhood
Receptor not considered
valuable enough for
significant impacts to
arise.
Splash zone estuarine
rocky habitat
Intertidal mudflats Parish/
Neighbourhood
Receptor not considered
valuable enough for
significant impacts to
arise. No direct or indirect
impacts predicted.
Shellfish including
native oyster
Subtidal habitats Negligible Only one individual native
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/
Neighbourhood
Only one individual of this
highly mobile species was
recorded. Receptor not
sufficiently valuable for
impacts to arise.
Sternaspis scutata Subtidal habitats Parish/
Neighbourhood
Only one individual of this
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 250m3.
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 37,000m3 (19,000m3 from the area in front of the northern mooring dolphins on
the east side of the jetty and 18,000m3 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 250m3 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 37,000m3.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 250m3 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 37,000m3 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 (250m3) 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 1st April and 31st 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 1st
April until 31st 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 1st April to 31st
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 1st April to 31st 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 4,036m3 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 + 0.3ha where berth pocket sides
slope)
0.73ha
Western navigation channel dredging
(the Northern Approach Channel)
1.36ha 1.36ha
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 250m3. 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 5000m3 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 164,000m3 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 40.8dBLAeq T during the night and 45 and 53.6dBLAeq 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 84.1dBLAeq
at 50m from source, dropping to 68.5dBLAeq 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 jetty (m)
50 100 150 200 300
LAeq 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 70dBLAeq T until 200m from the
source of the noise.
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Table 6-10 Cumulative unmitigated noise impacts during demolition
Distance from jetty (m)
50 100 150 200 300
LAeq 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 37,000m3 (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 14th 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 31st 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 4036m3 (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
SAC – Loss of habitat
Permanent No significant effect on feature of
International importance
Plymouth Sound and Estuaries
SAC – physical damage to
habitats as a result of
increased siltation, release of
contaminants from
contaminated sediment and
pollution
Temporary No significant effect on feature of
International importance
Bird species associated with
the Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI –
disturbance to SPA features
by piling
Temporary No significant effect on feature of
International importance
Bird species associated with
the Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI –
Disturbance to SSSI features
by piling
Temporary No significant effect on feature of
National importance
Bird species associated with
the Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI –
disturbance from other
construction activities
Temporary No significant effect on feature of
International importance
Bird species associated with
the Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI – loss and
damage to foraging habitats as
a result of increased siltation
and pollution
Loss – permanent
Damage - temporary
No significant effect on feature of
International importance
Whitsand and Looe Bay MCZ
– physical damage to habitats
and species as a result of
increased siltation
Temporary No significant effect on feature of
National importance
Seagrass beds – Loss and
damage of habitat by piling
and dredging
Loss – permanent
Damage - temporary
No significant effect on feature of
County importance
Migratory fish – (Atlantic Disturbance – temporary No significant effect on feature of
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salmon, allis shad, European
smelt, sea trout, European eel,
twaite shad, river lamprey, sea
lamprey) disturbance/mortality
to migratory fish
Mortality - permanent International importance
Migratory fish – (Atlantic
salmon, allis shad, European
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
Loss – permanent
Damage - temporary
No significant effect on feature of
International importance
Other fish species (bass,
lemon sole, sole, sprat,
monkfish, mackerel, spurdog,
whiting) –
disturbance/mortality to
resident fish species
Disturbance – temporary
Mortality - permanent
No significant effect on feature of
Regional importance
Other fish species (bass,
lemon sole, sole, sprat,
monkfish, mackerel, spurdog,
whiting) – loss and damage to
foraging habitats as a result of
increased siltation and
pollution
Loss – permanent
Damage - temporary
No significant effect on feature of
Regional importance
Marine mammals (bottlenose
dolphin, harbour porpoise and
grey seal) – disturbance from
piling and dredging
Temporary No significant effect on feature of
District/Borough importance
Operation
Subtidal mudflats associated
with Plymouth Sound and
Estuaries SAC – physical
damage to habitats as a result
of increased siltation
Temporary No significant effects on feature of
International importance
Subtidal mudflats associated
with Plymouth Sound and
Estuaries SAC – physical
damage to habitats as a result
of pollution or toxic
contamination
Temporary No significant effect on feature of
International importance
Bird species associated with
Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI –
disturbance to birds by
Temporary No significant effect on features of
International and National
importance
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maintenance dredging
Bird species associated with
Tamar Estuaries Complex
SPA, Lynher Estuary SSSI, St
John’s Lake SSSI –
disturbance to birds by re-
fuelling operations
Temporary No significant effect on features of
International and National
importance
Bird species associated with
Tamar Estuaries Complex
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
Temporary 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
Temporary No significant effect on feature of
National importance.
Seagrass beds – loss and
damage of habitat by
maintenance dredging
Loss – permanent
Damage - temporary
No significant effect on this feature
of County importance
Seagrass beds – loss and
damage of habitat by pollution
Loss – permanent
Damage - temporary
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 to
migratory fish by maintenance
dredging
Temporary No significant effect on this feature
of International importance
Migratory fish (Atlantic salmon,
allis shad, European 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 from maintenance
dredging
Loss – permanent
Damage - temporary
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
Temporary No significant effect on this feature
of Regional importance
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Other fish species (bass,
lemon sole, sole, sprat,
monkfish, mackerel, spurdog,
whiting) – damage to
spawning habitat for resident
species as a result of
maintenance dredging,
pollution and toxic
contamination
Temporary No significant effect on this feature
of Regional importance
Marine mammals (bottlenose
dolphin, harbour porpoise and
grey seal) – disturbance from
maintenance dredging
Temporary No significant effect on these
features of District/Borough
importance
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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
of resource
or receptor
Description
High
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 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
Medium
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 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
Low
Heritage assets displaying limited evidential, historic, aesthetic or communal value as identified by Conservation Principles 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
of resource
or receptor
Description
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.
Negligible
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 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
Uncertain The importance of the resource has not been ascertained. 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
of Change Description of Change
High
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
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.
Medium
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
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.
Low
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
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.
Negligible
Very minor changes to archaeological or historic building elements or setting
Very minor changes to key historic landscape elements, parcels or components; virtually 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
No change to archaeological elements or historic building fabric and setting
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
Magnitude
of Change
High Major Major Slight to
Moderate
Neutral/ not
significant
Unknown
Medium Major Moderate Slight to
Moderate
Neutral/ not
significant
Unknown
Low Slight to
Moderate Slight
Slight to
Neutral
Neutral/ not
significant
Unknown
Negligibl
e
Neutral/
not
significant
Neutral/ not
significant
Neutral/ not
significant
Neutral/ not
significant
Unknown
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
Major Adverse
Substantial harm or total loss of the value of a designated heritage asset (or
asset worthy of designation) such that Development should not be consented
unless substantial public benefit is delivered by the Development.
Moderate Adverse
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.
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.
Slight Adverse
Harm to a non-designated heritage asset that can be adequately compensated
through the implementation of a programme of industry standard mitigation
measures.
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
Significant Effect that is nil, imperceptible and not significant.
Slight Beneficial Development will deliver a positive contribution and / or better reveal the value
of a non-designated heritage asset.
Moderate
Beneficial
Development will deliver a positive contribution and / or better reveal the value
of a designated heritage asset (or asset worthy of designation) such that an
application should be treated favourably.
Major Beneficial
Development will deliver a positive contribution and / or better reveal the value
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 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
Consulted with Cornwall Council Historic Environment Service
Cornwall Council Historic Environment Service
No response to scoping opinion. Response received from Phil Copleston, Historic Environment Planning Advice Officer at Cornwall Council, who had no concerns relating to the historic environment over the proposed Development
None required
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 37,000m3 (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
anent
Proposed
Mitigation
Measures
Significa
nce
rating
Significant
Effect
Impact of vessel
anchoring during
construction and
operation
Permanent None Slight
Impacts of dredging
upon small vessel
Permanent None Neutral
Impacts of dredging
upon mooring buoy
Permanent None Neutral
Impacts of dredging
upon debris
Permanent None Slight
Impacts of dredging
upon cables and
possible cables
Permanent None Neutral
Impact of dredging
upon potential
archaeology
Permanent Archaeological
watching brief and
finds reporting
protocol during
dredging
operations
High/
Medium
Slight,
following
mitigation
Impact of piling upon
potential archaeology
Permanent None Unknown
Impact of vessel
anchoring upon
potential archaeology
Permanent None Unknown
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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
for England
(NPSE)
The Noise Policy Statement for
England (published on 15 March
2010) sets out the long term
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.
None. NPSE provides an overarching
policy framework that has been
embraced in assessing noise impacts.
National Planning Policy Framework. (July 2012)
National Planning Policy
Framework (NPPF) formally
published on 27 March 2012.
None. NPPF provides an overarching policy framework that has been embraced in assessing noise impacts.
Environment Protection
Act 1990
Once the development is
completed, noise and vibration
arising can be considered in
terms of statutory nuisance. Part
3 of the Environmental
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.
None, for reference indicating the
importance of good acoustic design. The
assessment has considered BS4142
when assessing operational noise
impacts.
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
procedures for those
undertaking works to obtain
‘Prior Consent’ for construction
works within agreed noise limits.
advise that a Section 61 Consent
Application is required.
The Noise Insulation
Regulations 1975 (as
amended 1988)
Regulation 5 provides relevant
authorities with discretionary
powers to provide noise
insulation at dwellings to reduce
the impact of construction noise
No relevance at this stage of the
assessment.
BS5228:1 2009
+A1:2014 Code of
practice for noise and
vibration control on
construction and open
sites. Noise
BS 5228 gives
recommendations for basic
methods of noise control relating
to construction and open sites
where work activities/operations
generate significant noise levels,
including industry-specific
guidance.
Assessment carried out in accordance
with BS5228
BS 6472-1:2008: Guide
to Evaluation of Human
Exposure to Vibration in
Buildings
BS 6472 provides guidance on
predicting human response to
vibration in buildings. Frequency
weighting curves for human
beings exposed to whole-body
vibration are included, together
with advice on measurement
methods to be employed.
None. Distance separation between
construction works and receptor
locations means that vibration impacts
are unlikely.
BS8223: 2014: Sound
insulation and noise
reduction for buildings –.
Code of practice
BS8223 gives recommendations
for the control of noise in and
around buildings, and suggests
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
Internal noise levels for living rooms and
bedrooms set out in BS8233 have been
considered.
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 LAeq,T; LA90; LA10; LAmin and LAmax 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 (LA90) 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 LAeq 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 LAeq,(16hour) -
Dining Dining room
/area
40dB LAeq,(16hour) -
Sleeping
(Daytime resting)
Bedroom 35dB LAeq,(16hour) 30dB LAeq,(8hour)
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. LAeq 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)
Assessment category and threshold value period
(LAeq)
Threshold value, in decibels (dB)
Category A (A)
Category B (B)
Category C (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 LAeq 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 LAeq
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 LAeq
Major
Daytime noise levels at houses in excess of 70 dB LAeq (12 hour)
Saturday (afternoon), Sunday and weekday evening noise levels at houses
in excess of 65 dB LAeq (1 hour)
Night-time noise levels at houses in excess of 60 dB LAeq (1 hour)
Moderate
Daytime noise levels at houses in the range between 65 to 70 dB LAeq (12
hour)
Saturday (afternoon), Sunday and weekday evening noise levels at houses
in excess of 60 dB LAeq (1 hour)
Night-time noise levels at houses in excess of 55 dB LAeq (1 hour)
Minor
Daytime noise levels at houses in the range between 55 to 65 dB LAeq (12
hour)
Saturday (afternoon), Sunday and weekday evening noise levels at houses
in excess of 55 dB LAeq (1 hour)
Night-time noise levels at houses in excess of 45 dB LAeq (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
resource or receptor
Criteria
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
impact Very High High Medium Low Negligible
Major Very Large Large or Very
Large
Moderate or
Large
Slight or
Moderate
Slight
Moderate Large or Very
Large
Moderate or
Large
Moderate Slight Neutral or
Slight
Minor Moderate or
Large
Slight or
Moderate
Slight Neutral or
Slight
Neutral or
Slight
Negligible Slight Slight Neutral or
Slight
Neutral or
Slight
Neutral
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 Council Environmental Health Officer
Discussed existing noise climate in area of Development and existing noise sources
Noise surveys carried out at agreed locations (locations listed in Table 8-8)
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
Receptors
Distance from
Site Boundary
(m)
NM1 Behind 47 Thanckes Drive 740
NM2 Behind 2 Albion Road 490
NM3
Yonderberry Cottages (near Wilcove
Inn) 876
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 LAeq,T; LA90; LA10; LAmin and LAmax 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; LAeq, LAMAX, LAMIN, LA1, LA10, LA50, LA90 and LA99. 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
Location Period LAeq,T
LA90
LAmax LAmin Average Minimum Maximum
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 (LAr,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 LAeq 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
Sensitive Receptor Highest
Predicted Noise (LAeq,T) dB
Magnitude of Impact Significance of
Impact
NM1 Behind 47 Thanckes Drive 55.6 Minor Adverse
Slight or
Moderate
Adverse
NM2 Behind 2 Albion Road 59.2 Minor Adverse
Slight or
Moderate
Adverse
NM3 Yonderberry Cottages (near
Wilcove Inn) 54.2 Minor Adverse
Slight or
Moderate
Adverse
NM4 12 Cove Meadow 54.3 Minor Adverse
Slight or
Moderate
Adverse
NM5 2 Pato Point 58.9 Minor Adverse
Slight or
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
Sensitive Receptor
Highest Predicted
Noise (LAeq,T) dB
Magnitude of Impact
Significance of Impact
NM1 Behind 47 Thanckes Drive 42.4 Minor Adverse Moderate
Adverse
NM2 Behind 2 Albion Road 46.0 Moderate Adverse Moderate
Adverse
NM3 Yonderberry Cottages (near
Wilcove Inn) 40.9 Minor Adverse
Moderate
Adverse
NM4 12 Cove Meadow 41.1 Minor Adverse Moderate
Adverse
NM5 2 Pato Point 45.6 Moderate Adverse Moderate
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
Sensitive Receptor
Highest Predicted
Noise (LAeq,T) dB
Magnitude of Impact
Significance of Impact
NM1 Behind 47 Thanckes Drive 55.6 Minor Adverse Moderate
Adverse
NM2 Behind 2 Albion Road 59.2 Minor Adverse Moderate
Adverse
NM3 Yonderberry Cottages (near
Wilcove Inn) 54.2 Minor Adverse
Moderate
Adverse
NM4 12 Cove Meadow 54.3 Minor Adverse Moderate
Adverse
NM5 2 Pato Point 58.9 Minor Adverse Moderate
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 (LA90) noise levels are very low at night, with LA90 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
Receptors Distance Jetty (m)
Plant Noise Limit dB(A)
Tonal Penalty
(BS 4142)
Predicted Noise Rating Impact (LAr,Tr)
NM1 Behind 47 Thanckes Drive 740 80 5 22.6
NM2 Behind 2 Albion Road 490 80 5 26.2
NM3 Yonderberry Cottages (near
Wilcove Inn) 876 80 5 21.1
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 (LAr,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 (LAr,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
Construction Noise Impacts
Temporary Daytime construction noise
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
Framework (Ref 9-2)
Requires landscape to be taken
into account in the planning
process through protection and
enhancement of landscapes.
Confirms National Parks and
Areas of Outstanding Natural
Beauty (AONB) have the highest
status of protection in relation to
landscape and scenic beauty
(under the National Parks and
Access to the Countryside Act,
1949, and Countryside and
Rights of Way Act, 2000,
respectively).
The Development does not fall within a
protected landscape; however the Tamar
Valley AONB is situated approximately
1km north west of the Development at its
nearest point. The setting of the AONB
has therefore been taken into account in
this assessment, along with wider
landscape character and visual amenity
considerations. There are not anticipated
to be significant impacts on landscape
character or the setting of the AONB as a
result of the Development.
Caradon Local Plan First
Alteration (August 2007)
: Policy CL7 -
Development Near Areas
of Outstanding Natural
Beauty or Heritage Coast
(Ref 9-3)
Requires character and
appreciation of AONBs to be
taken into account in respect of
development near these
designated areas. Development
which will be unduly prominent
from view points within such
areas or will adversely affect the
view towards such areas from
The Tamar Valley AONB is situated
approximately 1km north west of the
Development at its nearest point. Views
from and to the AONB have been taken
into account in this assessment. There
are not anticipated to be significant
impacts on these views as a result of the
Development.
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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
Sensitivity
Definition of Sensitivity Examples
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
Sensitivity
Definition of Sensitivity Examples
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
Sensitivity
Definition of Sensitivity Examples
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
Magnitude
Definition of 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
Magnitude
Definition of 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
MA
GN
ITU
DE
High Moderate Moderate / Major Major
Medium Minor / Moderate Moderate Moderate / Major
Low Minor Minor / Negligible Moderate
Negligible Negligible Negligible Negligible
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 13th 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/
permanent
Proposed
mitigation
measures
Significance
rating
Significant
effect
Construction Phase
Impact – Landscape &
Visual Amenity
Temporary landscape
and visual disruption.
Temporary Moderate negative Not significant
Operational Phase
Landscape
Overall, landscape
character, composition
and quality would
remain largely
unchanged.
Permanent Minor negative Not significant
Decommissioning
Phase Impact –
Landscape & Visual
Amenity
Temporary landscape
and visual disruption.
Temporary Moderate negative Not significant
Visual Amenity
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.
Permanent Minor negative Not significant
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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
(BPM) (COPA 1974)
"Practicable" means reasonably practicable having regard among
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 decibels
The ear is not as effective in hearing low frequency sounds as it is
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
MCAA
Multi-Agency Geographical Information for the Countryside
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
3-2
3-3
The Town and Country Planning (Development Management Procedure) (England)
(Amendment) Order 2013
Cornwall Council, Statement of Community Involvement, December 2011, available:
http://www.cornwall.gov.uk/media/3635991/SCI-as-Amended-220612.pdf
Town and Country Planning EIA Regulations
3-4
3.5
3.6
Marine Works EIA Regulations
Town and Country Planning Act 1990 (as amended)
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
Hyder Consulting (UK) Limited-2212959 Page 214
Chapter Five
5-1
5-2
Contaminated Land Report 11. Model Procedures for the Management of Land
Contamination. Defra/Environment Agency. September 2004.
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
5-4
1:50,000 series geology map (Drift Edition) Sheet 348 Plymouth. British Geological Survey.
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
5.10
5-11
Technical Annex 1 of OSPAR Guidelines for the Management of Dredged Material
(Reference number: 2009/4) OSPAR Commission
A desk study to assess the impact of dredging activity on the Tamar Estuary. PML
Applications Ltd. January 2004
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
5-14
5-15
5-16
5.17
Canadian Council of Ministers of the Environment (CCME) Canadian Environmental Quality
Guidelines. http://ceqg-rcqe.ccme.ca/ Website accessed 06/09/13
Construction Industry Research & Information Association (CIRIA) C650 – Environmental
Good Practice on Site, 2nd Ed. CIRIA. 2005
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
Drainage and the Water Environment: HD 45/09. (Highways Agency, 2009)
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
Hyder Consulting (UK) Limited-2212959 Page 215
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.