SEABANK 3 - A leading UK & Ireland energy …...Seabank 3 PEI Report – Glossary May 2014...

SEABANK 3

Preliminary Environmental Information Report Volume I

Prepared for:SSE plcMay 2014

Seabank 3 PEI Report - Preface

May 2014

PREFACE

This document comprises the Volume I of the Preliminary Environmental Information Report

that has been prepared in support of a DCO Application for the construction and operation of

Seabank 3.

The Preliminary Environmental Information Report comprises the following documents:

• The Non Technical Summary;

• Volume I: Preliminary Environmental Information Report;

• Volume II: Technical Appendices; and

• Volume III: Figures.

Figures based on Ordnance Survey® maps in this report have been reproduced under OS

License. © Crown copyright, All rights reserved. 2013. Licence number 0100031673.

Seabank 3 PEI Report - Preface

May 2014

Project Title: Seabank 3

Report Title: Preliminary Environmental Information Report: Volume I

Project No: 47064101

Client Name: SSE

Issued By: URS Infrastructure & Environment UK Limited

Document Production / Approval Record

Issue No: Name Signature Date Position

Prepared by

Natalie Williams Natalie Williams May 2014 Environmental Consultant

Checked by

Neil Titley Neil Titley May 2014 Associate

Approved by

Richard Lowe Richard Lowe May 2014 Technical Director

Document Revision Record

Issue No Date Details of Revisions

1 May 2014 PEI Report

Seabank 3 PEI Report – Glossary

May 2014

Abbreviations

Abbreviation Term

” Inch

°C Celsius

µg/m3 Micrograms per Cubic Metre

AADT Annual Average Daily Traffic

ABI Annual Business Inquiry

AGI Above Ground Installation

AOD Above Ordinance Datum

APFP Applications: Prescribed Forms and Procedure

APHO Association of Public Health Observatories

AQAP Air Quality Action Plan

AQMA Air Quality Management Area

ATC Automatic Traffic Count

AWTS Avon Wildlife Trust Site

BAP Biodiversity Action Plan

BAT Best Available Techniques

BCC Bristol City Council

BCHER Bristol City HER

BDW Boiler Feed Water

bgl Below Ground Level

BGS British Geological Survey

BIS Business Innovation and Skills

BOCC Bird of Conservation Concern

BRE Building Research Establishment

BREF Reference Document

BRERC Bristol Regional Environmental Records Centre

BRO Bristol Records Office

BS British Standard

BTEX Benzene, Toluene, Ethylbenzene and Xylenes

BTO British Trust for Ornithology

CAA Civil Aviation Association

CBR California Bearing Ratio

CCGT Combined Cycle Gas Turbine

CCR Carbon Capture Ready

CCS Carbon Capture and Storage

CCTV Closed Circuit Television

CCW Countryside Council for Wales

CDM Construction Design and Management


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Abbreviation Term

CEMARS Certified Emissions Management and Reduction Scheme

CEMP Construction Environmental Management Plan

CEMS Continuous Emissions Monitoring System

CFA Continuous Flight Auger

CHP Combined Heat and Power

CIEEM Chartered Institute of Ecology and Environmental Management

CLPVEs Critical Levels Protection of Vegetation and Ecosystems

CLR11 Defra’s Contaminated Land Report 11

CMS Construction Method Statement

CO Carbon Monoxide

CO2 Carbon Dioxide

COMAH Control of Major Accident Hazards

COPA Control of Pollution Act 1974

COSHH Control of Substances Hazardous to Health

CPT Cone Penetration Test

CRoW The Countryside and Rights of Way Act 2000

CRTN Calculation of Road Traffic Noise

CSM Conceptual Site Model

CTMP Construction Traffic Management Plan

CW Chemical Warfare

DAS Design and Access Statement

dB Decibel

DCLG Department for Communities and Local Government

DCMS Demolition and Construction Method Statement

DCO Development Consent Order

DECC Department for Energy and Climate Change

DETR Department for the Environment, Transport and the Regions

DfT Department for Transport

DMRB The Design Manual for Roads and Bridges

DOE Department of the Environment

DPDs Development Plan Documents

DQRA Detailed Quantitative Risk Assessment

EA Environment Agency

EfW Energy from Waste

EH English Heritage

EIA Environmental Impact Assessment

ELVs Emission Limit Values

EMF Electromagnetic Fields

EMR Electricity Market Reform


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Abbreviation Term

EOH Equivalent Operating Hours

EPC Engineering, Procurement and Construction Contractor

EPUK Environmental Protection UK

EQS Environmental Quality Standards

ES Environmental Statement

FRA Flood Risk Assessment

FTE Full Time Equivalent

FTW Full Time Equivalents

GAC Generic Assessment Criteria

GCC Gloucestershire County Council

GI Ground Investigation

GIS Gas Insulated Switchgear

GPSS Government Pipeline and Storage System

GQRA Generic Quantitative Risk Assessment

GW Gigawatt

GWh/day Gigawatt hour per day

H2 Hydrogen

ha Hectare

HA Highways Agency

HAZOP Hazard and Operability Assessment

HC Hydrocarbons

HDD Horizontal Directional Drilling

HDV Heavy Duty Vehicle

HER Historic Environment Record

HGV Heavy Goods Vehicle

HIA Health Impact Assessment

HPA Health Protection Agency

HRA Habitats Regulations Assessment

HRSG Heat Recovery Steam Generator

Hz Hertz

IAQM Institute of Air Quality Management

IBA Important Bird Area

ICE Institution of Civil Engineers

ICNIRP International Commission on Non-Ionising Radiation Protection

IEA Institute of Environmental Assessment

IED Industrial Emissions Directive

IEEM Institute of Ecology and Environmental Management

IEMA The Institute of Environmental Management and Assessment

IMD Index of Multiple Deprivation


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Abbreviation Term

IPC Infrastructure Planning Commission

IPPC Integrated Pollution Prevention and Control Directive

IROPI Imperative Reasons of Overriding Public Interest

ISO International (ISO) Standards

IUCN International Union for Conservation of Nature

JSNA Joint Strategic Needs Assessment

kg Kilogram

km Kilometre

kV kilovolt

kWh Kilowatt hour

LCPD Large Combustion Plant Directive

LNG Liquefied Natural Gas

LNR Local Nature Reserves

LSIDB Lower Severn Internal Drainage Board

Lw Sound Power Levels

m Metre

m/s Metres per second

MAGIC Multi-agency Geographic Information for the Countryside

mbars Milibars

mm Millimetre

mm/s Millimetre per second

MMO Marine Management Organisation

MMP Materials Management Plan

MW Megawatt

MWe Megawatt Electrical

NAQS National Air Quality Strategy

NE Natural England

NERC Natural Environment and Rural Communities

NETS National Electricity Transmission System

NG National Grid

ng/m3 Nanograms per cubic metre

NGG National Grid Gas

NH3 Ammonia

NID National Infrastructure Directorate

NNR National Nature Reserve

NO2 Nitrogen Dioxide

NOx Nitrogen

NPPF National Planning Policy Framework

NPS National Policy Statement


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Abbreviation Term

NR National Rail

NSIP National Significant Infrastructure Project

NTS Non-Technical Summary

NTS National Transmission System

O4B Open4Business

OCGT Open Cycle Gas Turbine

ODPM Office of the Deputy Prime Minister

OHLs Overhead Line

ONS Office for National Statistics

OS Ordinance Survey

PAH Polycyclic Aromatic Hydrocarbons

Pb Lead

PEI Preliminary Environmental Information

PHE Public Health England

PIAs Personal Injury Accidents

PIG Pipeline Inspection Gauge

PINS The Planning Inspectorate

PM10 Particulate Matter

PM2.5 Particulate Matter

PPG Pollution Prevention Guidelines

ppm Parts Per Million

ppv Peak Particle Velocity

PRA Preliminary Risk Assessment

PROW Public Right of Way

PVC Polyvinyl Chloride

RBMP River Basin Management Plans

ROW Right of Way

SAC Special Area Conservation

SDL` Severnside Developments Ltd

SERC Severnside Energy Recovery Centre

SGC South Gloucestershire Council

SGHER South Gloucestershire HER

SINC Site of Importance for Nature Conservation

SITA The Severnside Energy Recovery Centre

SNCI Sites of Nature Conservation Interest

SO2 Sulphur Dioxide

SoCC Statement of Community Consultation

SoS Secretary of State

SPA Special Protection Area


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Abbreviation Term

SPDs Supplementary Planning Documents

SPGs Supplementary Planning Guidance

SPL Seabank Power Ltd

sq ft Square foot

SSAC Site Specific Assessment Criteria

SSSI Site of Special Scientific Interest

SuDS Sustainable Urban Drainage System techniques

TA Transport Assessment

TPO Tree Preservation Order

TTWA Travel to Work Area

UK BAP UK Biodiversity Action Plan

ULCS Ultra Large Container Ship

UWE University of West of England

UXO Unexploded Ordnance

VOCs Volatile Organic Compounds

WAC Waste Acceptance Criteria

WAP1 Western Approaches Business Park

WeBS Wetland Bird Survey

WebTAG Web-based Transport Analysis Guidance

WFD Water Framework Directive

WHO World Health Organisation

WNS Wildlife Network Site

WSI Written Schemes of Investigation

WTNs Waste Transfer Notes

WWII World War Two

WWTW Waste Water Treatment Works

ZTV Zone of Theoretical Visibility


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Glossary of Terms

PEI Report Preliminary Environmental Information Report

Ancillary Development

A range of matters including acquisition of land, intrusive works and other connections and agreements (defined by The Planning Act 2008, Section 120).

Associated Development

Development associated with the principal development within the site for which DCO is being sought, such as pipework, control rooms, water supply, storage and purification equipment, gas receiving equipment, grid connection infrastructure and supporting site infrastructure (defined by The Planning Act 2008, Section 120).

Associated Infrastructure

A reference in the PEI Report to Associated Development located outside of the Proposed Development Site (but still within the DCO Site). It includes cooling water pipeline, and electrical and utilities connections.

Black-start The ability to start-up without assistance from the national electricity grid in the event of a total or partial shutdown of the national transmission system.

Carbon Capture Ready (CCR)

A generating station that adheres to the UK CCR Guidance. A generating station that is CCR will have sufficient land adjacent to the generating station to install carbon capture technology at some point in the future, should the technology become viable.

Carbon Capture Storage

Carbon capture and storage (CCS) is the process of capturing waste carbon dioxide (CO2) from a power plant and transporting it to a storage site (an underground reservoir for example).

Combined Cycle Gas Turbines (CCGT)

CCGT is a form of highly efficient energy generation technology that combines a gas-fired turbine with a steam turbine. It captures waste heat from the gas-fired turbine which would otherwise be emitted to atmosphere to drive the steam turbine, hence increasing the electrical efficiency of the plant.

CCR Site This is an area of approximately 6.3ha within the eastern part of the Proposed Development Site which is reserved for the future retrofit of Carbon Capture plant should this ever be required.

CHP Ready A generating station that adheres to the UK CHP Guidance. A generating station that is CHP-R is designed to be ready, with minimum modification, to export heat should the demand become available.

Cooling Water Pipeline

A proposed water supply pipeline that connects the Proposed Development to the Bristol Waste Water Treatment Works.

Cooling Water Pipeline Corridor

A corridor or area within which the proposed cooling water pipeline and enabling and construction works associated with the pipeline will be installed and completed.

DCO Site The application site for which DCO is being sought. It comprises an area of approximately 38ha and constitutes the following two components: The ‘Proposed Development Site’ and ‘Other DCO Land’.

Development Consent Order

A development consent order, when issued, combines the grant of planning permission with a range of other consents that in other circumstances have to be applied for separately, such as listed building consent. All applications for development consent orders will be made to the Planning Inspectorate. The Planning Inspectorate makes a recommendation to the Secretary of State, who in turns determines the application.

Development Parcels Areas of land within the DCO Site that have been designated for different uses within the PEI Report.


May 2014


Dry-cooling A type of cooling system that uses air to cool the steam exiting a gas turbine.

Electrical Connection The underground or above ground connection of the Proposed Development to Seabank substation that extends approximately 440m across the existing Seabank 1 & 2 site.

Environmental Impact Assessment

A process for determining how a Project may affect the environment. The results of an Environmental Impact Assessment should establish a development’s principal potential effects, their significance and how they interact. This information is summarised in a Preliminary Environmental Information Report or Environmental Statement, depending on what stage the project is at.

Environmental Statement

A report describing the findings and conclusions of the Environmental Impact Assessment process.

Finished Floor Level The finished level of the upper surface of the floor inclusive of all services.

Generating Station Site

The area within the Proposed Development Site where the generation equipment is located.

Heat Recovery Steam Generator

A heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat from a hot gas stream.

Hybrid Cooling System

A cooling system that extracts waste heat to the atmosphere and uses a mixture of air and water to cool the steam exiting the gas turbine.

Multi-shaft A configuration of CCGT that includes two gas turbines and generators (the same number as two single-shaft units), but supplies steam from the HRSG to a separate steam turbine and generator that is common to each train.

Nationally Significant Infrastructure Project

Infrastructure projects which are dealt with by the Planning Inspectorate are known as Nationally Significant Infrastructure Projects (NSIPs). Projects are within the five general fields of energy, transport, water, waste water and waste. Examples include power stations, railways and major roads, reservoirs, harbours, airports, wind farms and sewage treatment works. The thresholds are set out in sections 15-30 of the 2008 Planning Act.

The Proposed Development falls within the definition of a ‘Nationally Significant Infrastructure Project’ (NSIP) under Section 14(1)(a) and Sections 15(2) of the Planning Act 2008 (Ref. 2-1), as it is an onshore generating station within England that will have a generating capacity greater than 50MW gross output.

Open cycle A form of energy generation technology that does not capture waste heat to fire a steam turbine.

Other DCO Land Approximately 19ha of land within the DCO Site that is outside of the Proposed Development Site and contains the proposed electrical and utilities connection and proposed cooling water pipeline corridor.

Peaking Plant Generating plant that is designed to operate for short periods of time and to ‘top up’ the national grid during periods of high demand / peaks.

Planning Inspectorate

The agency responsible for operating the planning process for nationally significant infrastructure projects (NSIPs).

Preliminary Environmental Information (PEI)

PEI is defined in the Infrastructure Planning (Environmental Impact Assessment) Regulations 2009 as “information referred to in Part 1 of Schedule 4 (information for inclusion in environmental statements) which (a) has been compiled by the applicant; and (b) is reasonably required to assess the environmental effects of the development (and of any associated development)”.


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Prescribed Persons Includes certain statutory consultees such as the Environment Agency and Natural England, relevant statutory undertakers, relevant local authorities, those with an interest in the land, and those who may be affected by the development.

Proposed Development Site

Part of the DCO Site comprising approximately 19ha situated immediately east of the existing Seabank 1 & 2 station for which DCO is being sought for the Proposed Development. It excludes the Other DCO Land, which contain the proposed cooling water corridor and electrical connection and utilities.

Public Right of Way An access track that is open to everyone including roads, paths or tracks, bridleways and can run through towns, countryside or private property.

Reciprocating Engine A highly efficient internal heat combustion engine which can achieve long-term availability levels and would be used for the Peaking Plant element of the Proposed Development.

Rochdale Envelope An approach that allows a range, or envelope of parameters to be applied for, as described in the Planning Inspectorate’s Advice Note 9.

Scoping A stage which occurs early in the project cycle identifying the key environmental issues and the procedures for determining the extent of and the approach to an EIA.

Scoping Opinion The Planning Inspectorate will consult the relevant consultees on the submitted scoping report, and will provide consolidated written opinion on the procedures for determining the extent of and the approach to an EIA.

Scoping Report A report by the Applicant on the results of the Scoping exercise as detailed above which is submitted to the Planning Inspectorate.

Single-shaft A configuration of CCGT that consists of only one gas turbine, steam turbine, generator and HRSG per CCGT unit, with the gas turbine and steam turbine coupled to the generator.

Supplementary Firing A method of producing additional steam to generate additional electricity for short periods by firing a dedicated gas burner located between the gas turbine and the HRSG.

The Applicant SSE Seabank Land Investments Limited, a wholly owned subsidiary of SSE.

The Proposed Development

The term used to describe the Seabank 3 generating station. It excludes the cooling water pipeline corridor and electrical connection and utilities.

The Proposed Development Site

Approximately 19ha of the DCO Site that consists of the Seabank 3 generating station and CCR Site. It is wholly located within the administrative boundary of South Gloucestershire Council.

Utilities, Services and Landscaping Area

A 6.4ha area reserved for utilities connections, gas reception and landscaping, excluding the electrical connection and cooling water pipeline.

Wet-cooling A cooling system that uses water to cool the steam exiting a gas turbine.

Seabank 3 PEI Report – Volume I: Contents

May 2014

Contents

1. INTRODUCTION .......................................................................................... 1-1

1.1. Background ................................................................................................... 1-1 1.2. The Applicant ................................................................................................ 1-1 1.3. Location of the Proposed Development ......................................................... 1-1 1.4. The Proposed Development………………………….......................... ............. 1-2 1.5. Structure of this PEI Report…………………………………………… ............... 1-3 1.6. The Purpose of the Preliminary Environmental Information (PEI) Report ....... 1-3 1.7. Location of Information within the PEI Report ............................................... 1-4 1.8. Other Required Consents .............................................................................. 1-5 1.9. References ................................................................................................... 1-6

2. THE DEVELOPMENT CONSENT ORDER (DCO) AND EIA PROCESSES ............................................................................................... 2-1

2.1. Introduction .................................................................................................... 2-1 2.2. DCO Process ............................................................................................... 2-1 2.3. EIA Development .......................................................................................... 2-2 2.4. The EIA Scoping Exercise ............................................................................ 2-3 2.5. Non Key Issues ............................................................................................ 2-4 2.6. Preliminary Environmental Information ......................................................... 2-6 2.7. Design Parameters Used within the DCO Application ................................... 2-7 2.8. Consultation ................................................................................................. 2-8 2.9. PEI Report Availability ................................................................................. 2-10 2.9. References .................................................................................................. 2-11

3. THE SITE AND ITS SURROUNDINGS ........................................................ 3-1

3.1. Introduction ................................................................................................... 3-1 3.2. The Proposed Development Site ................................................................... 3-2 3.3. Existing Services with the Proposed Development Site ................................ 3-8 3.4. Proposed Development Site History ............................................................. 3-9 3.5. Area Surrounding the Proposed Development Site .......................................3-11 3.6. Other DCO Land.......................................................................................... 3-12 3.7. Sensitive Receptors in the Vicinity of the Proposed Development Site

and Other DCO Land .................................................................................. 3-18

4. PROJECT DESCRIPTION ........................................................................... 4-1

4.1. Introduction ................................................................................................... 4-1 4.2. Overview ...................................................................................................... 4-1 4.3. Description of the Proposed Development .................................................... 4-2 4.4. Hours of Operation and Shift Pattern ........................................................... 4-28 4.5. Employment ................................................................................................ 4-28 4.6. Nuisance Control ......................................................................................... 4-29 4.7. Operational Waste Streams ......................................................................... 4-29 4.8. Chemical and Utility Usage .......................................................................... 4-30 4.9. Safety and Emergency Planning .................................................................. 4-31 4.10. References .................................................................................................. 4-32


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5. ENABLING WORKS AND CONSTRUCTION .............................................. 5-1

5.1. Introduction ................................................................................................... 5-1 5.2. Enabling Works ............................................................................................ 5-1 5.3. Construction Phase ...................................................................................... 5-5 5.4. Operation .....................................................................................................5-19 5.5. Decommissioning ........................................................................................ 5-19 5.5. References .................................................................................................. 5-22

6. PROJECT NEEDS AND ALTERNATIVES ................................................... 6-1

6.1. The Need for the Proposed Development ..................................................... 6-1 6.2. Alternative Sites ............................................................................................ 6-2 6.3. Consideration of Alternative Locations with the Selected Site ....................... 6-3 6.4. Consideration of Alternative Layouts within the Selected Site ....................... 6-4 6.5. Alternative Technologies .............................................................................. 6-7 6.6. Associated Infrastructure .............................................................................6-11 6.7. Conclusions .................................................................................................6-11 6.8. References .................................................................................................. 6-11

7. ASSESSMENT METHODOLOGY ............................................................... 7-1

7.1. Introduction ................................................................................................... 7-1 7.2. EIA Methodology .......................................................................................... 7-1 7.3. Structure of this PEI Report .......................................................................... 7-5 7.4. Structure of PEI Report Chapters ................................................................. 7-7 7.5. Assumptions and Limitations .......................................................................7-14 7.6. References ..................................................................................................7-14

8. PLANNING POLICY CONTEXT ................................................................... 8-1

8.1. Introduction ................................................................................................... 8-1 8.2. The Planning Act and National Policy Statements for Energy ....................... 8-1 8.3. Other Relevant National Policy ..................................................................... 8-3 8.4. Local Planning Policy ................................................................................... 8-4 8.5. References ................................................................................................... 8-6

9. LAND USE, RECREATION AND SOCIO-ECONOMICS .............................. 9-1

9.1. Introduction ................................................................................................... 9-1 9.2. Assessment Methodology and Significance Criteria ..................................... 9-3 9.3. Baseline Conditions ...................................................................................... 9-6 9.4. Development Design and Impact Avoidance ............................................... 9-11 9.5. Potential Effects and Mitigation Measures ...................................................9-11 9.6. Residual Effects .......................................................................................... 9-22 9.7. Cumulative Effects .......................................................................................9-23 9.8. Impacts and Effects yet to be Determined ...................................................9-24 9.9. References ..................................................................................................9-25


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10. TRAFFIC AND TRANSPORT .....................................................................10-1

10.1. Introduction ..................................................................................................10-1 10.2. Assessment Methodology and Significance Criteria ....................................10-3 10.3. Baseline Conditions .....................................................................................10-9 10.4. Development Design and Impact Avoidance ............................................. 10-14 10.5. Potential Effects and Mitigation Measures ................................................. 10-15 10.6. Residual Effects ......................................................................................... 10-30 10.7. Cumulative Effects ..................................................................................... 10-30 10.8. Impacts and Effects yet to be Determined ................................................. 10-33 10.9. References ................................................................................................. 10-34

11. AIR QUALITY ..............................................................................................11-1

11.1. Introduction ..................................................................................................11-1 11.2. Assessment Methodology and Significance Criteria .....................................11-5 11.3. Baseline Conditions .................................................................................... 11-23 11.4. Development Design and Impact Avoidance .............................................. 11-34 11.5. Potential Effects and Mitigation Measures ................................................. 11-36 11.6. Residual Effects.......................................................................................... 11-50 11.7. Cumulative Effects ...................................................................................... 11-52 11.8. Impacts and Effects yet to be Determined .................................................. 11-54 11.9. References ................................................................................................. 11-55

12. NOISE AND VIBRATION ............................................................................12-1

12.1. Introduction ...................................................................................................12-1 12.2. Assessment Methodology and Significance Criteria ....................................12-3 12.3. Baseline Conditions ................................................................................... 12-12 12.4. Development Design and Impact Avoidance .............................................. 12-14 12.5. Potential Effects and Mitigation Measures ................................................. 12-15 12.6. Residual Effects.......................................................................................... 12-31 12.7. Cumulative Effects ...................................................................................... 12-32 12.8. Impacts and Effects yet to be Determined ................................................. 12-33 12.9. References ................................................................................................ 12-33

13. GROUND CONDITIONS .............................................................................13-1

13.1. Introduction ...................................................................................................13-1 13.2. Assessment Methodology and Significance Criteria .................................... 13-3 13.3. Baseline Conditions .....................................................................................13-7 13.4. Development Design and Impact Avoidance ............................................. 13-26 13.5. Potential Effects and Mitigation Measures ................................................. 13-26 13.6. Residual Effects.......................................................................................... 13-39 13.7. Cumulative Effects ...................................................................................... 13-41 13.8. Impacts and Effects yet to be Determined .................................................. 13-43 13.9. References ................................................................................................ 13-44


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14. FLOOD RISK, HYDROLOGY AND WATER RESOURCES .........................14-1

14.1. Introduction ...................................................................................................14-1 14.2. Assessment Methodology and Significance Criteria ....................................14-4 14.3. Baseline Conditions .....................................................................................14-8 14.4. Development Design and Impact Avoidance ............................................. 14-15 14.5. Potential Effects and Mitigation Measures ................................................. 14-16 14.6. Residual Effects.......................................................................................... 14-28 14.7. Cumulative Effect ...................................................................................... 14-33 14.8. Impacts and Effects yet to be Determined ................................................. 14-35 14.9. References ................................................................................................ 14-36

15. ARCHAEOLOGY AND CULTURAL HERITAGE ........................................15-1

15.1. Introduction .................................................................................................. 15-1 15.2. Assessment Methodology and Significance Criteria ....................................15-3 15.3. Baseline Conditions .....................................................................................15-8 15.4. Development Design and Impact Avoidance ............................................. 15-27 15.5. Potential Effects and Mitigation Measures .................................................. 15-28 15.6. Residual Effects ......................................................................................... 15-33 15.7. Cumulative Effects ..................................................................................... 15-36 15.8. Impacts and Effects yet to be Determined .................................................. 15-37 15.9. References ................................................................................................. 15-37

16. ECOLOGY AND HABITATS ........................................................................16-1

16.1. Introduction ..................................................................................................16-1 16.2. Assessment Methodology and Significance Criteria ....................................16-5 16.3. Baseline Conditions .................................................................................... 16-15 16.4. Development Design and Impact Avoidance .............................................. 16-31 16.5. Potential Effects and Mitigation Measures .................................................. 16-33 16.6. Residual Effects.......................................................................................... 16-46 16.7. Cumulative Effects ...................................................................................... 16-48 16.8. Impacts and Effects yet to be Determined .................................................. 16-50 16.9. References ................................................................................................. 16-52

17. LANDSCAPE AND VISUAL.........................................................................17-1

17.1. Introduction ..................................................................................................17-1 17.2. Assessment Methodology and Significance Criteria ................................... 17-12 17.3. Baseline Conditions .................................................................................... 17-19 17.4. Development Design and Impact Avoidance .............................................. 17-29 17.5. Potential Effects and Mitigation Measures .................................................. 17-30 17.6. Residual Effects.......................................................................................... 17-40 17.7. Cumulative Effects ...................................................................................... 17-42 17.8. Conclusions ................................................................................................ 17-44 17.9. References ................................................................................................. 17-46


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18. SUSTAINABILITY AND CLIMATE CHANGE .............................................18-1

18.1. Introduction ..................................................................................................18-1 18.2. Assessment Methodology and Significance Criteria ....................................18-1 18.3. Baseline Conditions .....................................................................................18-2 18.4. Development Design and Impact Avoidance ................................................18-2 18.5. Potential Effects and Mitigation Measures ...................................................18-2 18.6. Residual Effects.......................................................................................... 18-11 18.7. Cumulative Effects ...................................................................................... 18-11 18.8. Impacts and Effects yet to be Determined .................................................. 18-11 18.9. References ................................................................................................. 18-12

19. HEALTH ......................................................................................................19-1

19.1. Introduction ..................................................................................................19-1 19.2. Assessment Methodology and Significance Criteria ....................................19-2 19.3. Baseline Conditions .....................................................................................19-4 19.4. Development Design and Impact Avoidance ...............................................19-8 19.5. Potential Effects and Mitigation Measures ....................................................19-9 19.6. Residual Effects.......................................................................................... 19-17 19.7. Cumulative Effects ...................................................................................... 19-18 19.8. Impacts and Effects yet to be Determined .................................................. 19-19 19.9. References ................................................................................................. 19-19

20. CUMULATIVE EFFECTS ............................................................................20-1

20.1. Introduction .................................................................................................. 20-1 20.2. Legislation and Planning Policy Context ......................................................20-1 20.3. Assessment Methodology ............................................................................20-2 20.4. Combined Effects of Individual Effects - Type 1 ...........................................20-3 20.5. Combined Effects of the Proposed Development with Other

Development Schemes - Type 2 ..................................................................20-4 20.6. References ..................................................................................................20-5

21. RESIDUAL EFFECTS .................................................................................21-1

21.1. Introduction .................................................................................................. 21-1 21.2. Background .................................................................................................21-1 21.3. Summary of Residual Effects .......................................................................21-1 21.4. Summary and Conclusions ..........................................................................21-5


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Tables

Table 1-1 Location of Information within the PEI Report

Table 3-1 Historical Map Descriptions of the Proposed Development Site

Table 4-1 Proposed Development Parameters for the Single Shaft Configuration

Table 4-2 Proposed Development Parameters for the Multi Shaft Configuration

Table 4-3 Provision of Employment during Operation

Table 4-4 Expected Waste Streams associated with the Operational Proposed

Development

Table 4-5 Utility Usage

Table 5-1 Indicative Enabling and Construction Programme

Table 5-2 Estimated Plant Type and Equipment during Construction Activities

Table 7-1 Location of Schemes Considered within the Cumulative Effect Assessment

Table 9-1 Relevant Scoping Opinion Responses

Table 9-2 Socio-economic Effects by Geographical Scale

Table 9-3 Qualification Levels of the Working Population (aged 16-64)

Table 9-4 Employment by Occupation, July 2012 to June 2013

Table 9-5 Sector Employment Distribution, 2012

Table 9-6 Net Construction Employment in Bristol TTWA during the Peak Construction

Year

Table 9-7 Net Operation Employment

Table 9-8 Summary of Residual Effects

Table 9-9 Summary of Schemes Relevant to Cumulative Socio-Economic Effects

Table 10-1 Summary of Stakeholders Comments on Traffic and Transport

Table 10-2 Personal Injury Accident Data (01 May 2008 to 30 April 2013)

Table 10-3 Traffic Increase during Land Raising Works Prior to Additional Mitigation

Table 10-4 Traffic Increase during Land Raising Prior to Additional Mitigation – Sensitivity

Test

Table 10-5 Traffic Increase during Main Construction Works Prior to Additional

Mitigation

Table 10-6 Predicted Increase during Construction Phase following Mitigation Measures


Table 10-8 Predicted Cumulative Effects (Total Traffic including HGVs)

Table 11-1 Summary of Consultation Responses Relevant to Air Quality

Table 11-2 Air Quality Strategy Objectives – Protection of Human Health

Table 11-3 Critical Levels for the Protection of Vegetation and Ecosystems

Table 11-4 Alternative Design Schemes for Combustion Plant

Table 11-5 Modelled Stack Release Parameters

Table 11-6 Operational Phase – Potential Human Health Receptors

Table 11-7 Statutory Designated Sites of Ecological Interest within 10km of the Proposed

Development Site

Table 11-8 Descriptors Applied to the Predicted Adverse Effects of Fugitive Emissions of

Particulate Matter

Table 11-9 Determination of Magnitude of Change – Air Quality


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Table 11-10 Significance of Effects

Table 11-11 Ambient Data from Local Authority Secondary Sources

Table 11-12 Historic Ambient NO2 Monitoring Data

Table 11-13 Defra Mapped Background Data (1km grid squares)

Table 11-14 Primary Diffusion Tube Monitoring Locations

Table 11-15 Mean monitored Concentrations, 4 June - 30 Sept 2013 (µg/m3)

Table 11-16 Derived Baseline Concentrations (µg/m3)

Table 11-17 Predicted Baseline NOx Concentrations and Nitrogen Deposition Rates

at the Severn Estuary, 2019

Table 11-18 Summary of Construction Phase Dust Effects

Table 12-1 Relevant Scoping Opinion Responses to Noise and Vibration

Table 12-2 Construction Noise Thresholds at nearby Residential Dwellings

Table 12-3 Significance Criteria for Construction Noise

Table 12-4 Guidance Effects of Vibration for Human Response

Table 12-5 Significance Criteria for Operational Noise

Table 12-6 Scheme for Assessment of Changes in Road Traffic Noise Levels

Table 12-7 Free-field Ambient Noise Levels during Good Weather Conditions

Table 12-8 Observations during the Baseline Monitoring

Table 12-9 Threshold Values at Selected Receptors

Table 12-10 Predicted Free-Field Construction Noise Levels

Table 12-11 Difference between Predicted Construction Noise Level and Threshold Value

Table 12-12 Predicted Free-Field Daytime Construction Noise Levels associated with the

Cooling Water Pipeline Construction

Table 12-13 Predicted Noise Increases due to Construction Traffic

Table 12-14 Predicted Operational Noise Levels

Table 12-15 BS 4142 Assessment with 5dB Penalty – Single Shaft Configuration

Table 12-16 BS 4142 Assessment with 5dB Penalty – Multi Shaft Configuration

Table 12-17 Predicted Operational Noise Levels at Chittening Warth prior to Additional

Mitigation

Table 12-18 BS 4142 Assessment with No Penalty – Single Shaft

Table 12-19 BS 4142 Assessment with No Penalty – Multi Shaft

Table 12-20 Predicted Operational Noise Levels at Chittening Warth – with Mitigation



Table 13-2 Criteria to determine Magnitude of Change

Table 13-3 Description of Significance of Effects

Table 13-4 Historical Land Use within the Proposed Development Site and Other DCO

Land for Electrical Connection

Table 13-5 Historical Development of Land Surrounding the Proposed Development Site

and Other DCO Land for the Electrical Connection

Table 13-6 Summary of Ground Stability Hazards for the Proposed Development Site and

Electrical Connection

Table 13-7 Summary of Site Geological Strata under the Proposed Development Site


May 2014

Table 13-8 Summary of Ground Stability Hazards within the Cooling Water Pipeline

Corridor

Table 13-9 Proposed Development Site Environmental Sensitivity

Table 13-10 Potential Sources, Pathways and Receptors for Consideration during the Site

Preparation and Construction Phases

Table 13-11 Summary of Residual Effects (post-mitigation)

Table 13-12 Construction Phase Cumulative Issues


Table 14-2 Derivation of Importance of Water Resource

Table 14-3 Derivation of Magnitude of Change

Table 14-4 Derivation of Effect Significance

Table 14-5 Summary of Site Geological Strata

Table 14-6 Summary of Surface and Groundwater Receptors

Table 14-7 Summary of Risk Posed by all Flood Sources

Table 14-8 Residual Effect Significance for Water Quantity and Quality during

Construction Phase (Temporary)

Table 14-9 Residual Effect Significance for Water Quantity and Quality during Operation

Phase (Permanent)

Table 14-10 Construction Phase Effect on Flood Risk (Temporary)

Table 14-11 Operation Phase Effect on Flood Risk (Permanent)

Table 15-1 Scoping Opinion Responses Relevant to Archaeology and Cultural Heritage

Table 15-2 Criteria for Establishing the Importance of Heritage Assets

Table 15-3 Criteria for Establishing the Magnitude of Change on a Cultural Heritage Asset

Table 15-4 Matrix for Establishing Overall Significance of Effect

Table 15-5 Scheduled Monuments, Registered Parks and Gardens and Grade I and II*

listed buildings within 5km of the DCO Site

Table 15-6 Summary of Cultural Heritage Residual Effects


Table 16-2 Valuation of Ecological Receptors

Table 16-3 Magnitude of Change

Table 16-4 Classification of Effects

Table 16-5 Definitions of Effects

Table 16-6 Habitat Potential for Protected Species and Other Fauna within the Proposed

Development Site

Table 16-7 Resource Evaluation

Table 16-8 Value of Ecological Receptors under Future Baseline Conditions


Table 16-10 Proposed Survey Requirements for the Final ES

Table 17-1 Classification of Landscape and Visual Effects

Table 17-2 Description of Landscape and Visual Effects

Table 17-3 Summary of Local Landscape Character

Table 17-4 Visual Receptors and Representative Views

Table 18-1 Total footprint emissions



May 2014

Table 19-2 Scale of Health Effect

Table 19-3 Health indicator data for, England, South Gloucestershire and Bristol

Table 19-4 Life expectancy from birth

Table 19-5 ICNIRP Reference Levels vs Typical Ground-level UK Field Levels from

Overhead Power Lines

Table 19-6 Summary of Residual Effects (post-mitigation)

Table 21-1 Summary of Demolition, Construction and Operational Residual Effects

Plates

Plate 3-1 Photograph 1 from the centre of the Proposed Development Site, facing West

towards Seabank 1 & 2 [Date taken, 01/07/2013]

Plate 3-2 Photograph 2 from the Centre of the Generating Station Site, facing West

towards Seabank 1 & 2 [Date taken, 01/07/2013]

Plate 3-3 Photograph 3 from the Generating Station Site, facing Northeast towards the

redundant railway tracks. [Date taken, 01/07/2013]

Plate 3-4 Photograph 4 from the Generating Station Site, facing Southeast and showing

the existing trees [Date taken, 01/07/2013]

Plate 3-5 Photograph 5 from the CCR Site adjacent to the Red Rhine, facing East [Date

taken, 30/08/2012]

Plate 3-6 Photograph 6 from the Centre of the CCR Site, facing North [Date taken,

30/08/2012]

Plate 3-7 Photograph 7 showing the connection between the Proposed Development

Site and Seabank 1 & 2 [Date Taken 20 February 2013.]

Plate 3-8 Photograph 8 showing the entrance of Seabank 1 & 2 Site [Date Taken 20

February 2013]

Plate 3-9 Photograph 9 of Seabank 400kV Substation [Date Taken 20 February 2013]

Plate 3-10 Photograph 10 showing corner of Chittening Road and Severn Road [Date

Taken 11 November 2013]

Plate 3-11 Photograph 11 showing the corner of Smoke Lane and Chittening Road [Date

Taken 04/09/2013]

Plate 3-12 Photograph 12 showing footpath facing west running adjacent to the railway

[Date Taken 04/09/2013

Plate 3-13 Photograph 13 showing culvert facing south [Date Taken 04/09/2013]

Plate 3-14 Photograph 14 – Facing north across Popular Way East [Date Taken

04/09/2013]

Plate 3-15 Photograph 15 – Facing north from the Bristol WWTW Entrance [Date Taken

04/09/2013]

Plate 4-1 Single and Multi Shaft Arrangements

Plate 5-1 Estimated Personnel Onsite during Construction (Post Enabling Works)

Plate 9-1 Profile of Construction Employment (excluding enabling works)

Plate 10-1 Average Weekday Automatic Traffic Counts Results on the A403

Plate 10-2 Average Weekend Automatic Traffic Counts Results on the A403


May 2014

Plate 10-3 Traffic Counts Results at the Junction of Severn Road / A403 / Chittening

Road on Wednesday 14 November 2013

Plate 19-1 Source Pathway

Volume II - Appendices

Appendix A – Scoping Report and Scoping Opinion

Appendix B – Electronic Interference Assessment

Appendix C – Construction Environmental Management Plan

Appendix D – Planning Policy

Annex D1 - Socio-economic Legislation and Planning Policy Context

Annex D2 - Planning Policy Legislation and Planning Policy Context

Annex D3 - Air Quality Legislation and Planning Policy Context

Annex D4 - Noise and Vibration Legislation and Planning Policy Context

Annex D5 - Ground Conditions Planning Legislation and Policy Context

Annex D6 - Archaeology Legislation and Planning Policy Context

Annex D7 - Flood Risk, Hydrology and Water Resources Legislation and Planning

Policy Context

Annex D8 - Ecology Legislation and Planning Policy Context

Annex D9 - Landscape and Visual Legislation and Planning Policy Context

Annex D10 - Sustainability Legislation and Planning Policy Context

Appendix E – Traffic and Transport

Annex E1 – Meeting Notes

Annex E2 – Accident Data

Annex E3 – Trip Generation and Distribution

Annex E4 - Contractor Experience

Appendix F – Air Quality

Appendix G – Noise and Vibration

Appendix H – Archaeology

Annex H1 – Baseline Data

Annex H2 – Seabank Geotechnical Monitoring

Annex H3 – Figures

Appendix I – Ground Conditions


May 2014

Annex I1 – Waste Facilities

Annex I2 – Proposed Development Site Photographs

Annex I3 – Site Photographs of the Other DCO Land

Annex I4 – Phase II Geotechnical and Contamination Assessment

Appendix J – Flood

Annex J1 – Modelling Report

Annex J2 – Cumulative Impacts

Annex J3 – Topographic Data

Annex J4 – Proposed Development

Annex J5 – Sequential Tests

Annex J6 – Runoff Calculations

Annex J7 – Breach Results

Appendix K – Ecology

Annex K1 – HRA

Annex K2 – Phase 1 Habitat Survey Report

Annex K3 – Bat Survey

Annex K4 – Wintering Bird Survey

Annex K5 – Breeding Bird Survey

Annex K6 – Amphibian Survey

Annex K7 – Reptile Survey

Annex K8 – Designated and Non Designated Sites

Annex K9 – Phase I Habitat Survey Report for the Cooling Water Pipeline Corridor

Appendix L – Land and Visual

Annex L1 – Baseline Landscape Character

Annex L2 – Baseline Visual Assessment

Annex L3 – Landscape Impact Assessment

Annex L4 – Landscape Impact Assessment

Appendix M – Climate Change Impact Assessment

Appendix N – CHP Assessment


May 2014

Figures

Volume III – Figures.

Figure 1-1 Location of the Proposed Development Site

Figure 3-1 DCO Site and Development Land Parcels

Figure 3-2 Aerial Photograph of the Proposed Development Site

Figure 3-3 Location of Existing Services within the Proposed Development Site

Figure 3-4a Aerial View of the DCO Site and its Surrounds (Drawing 1 of 3)

Figure 3-4b Aerial View of the DCO Site and its Surrounds (Drawing 2 of 3)

Figure 3-4c Aerial View of the DCO Site and its Surrounds (Drawing 3 of 3)

Figure 3-5 Environmental Constraints

Figure 4-1a Development Parcels (Drawing 1 of 2)

Figure 4-1b Development Parcels (Drawing 2 of 2)

Figure 4-2 Indicative Maximum Layout of the Proposed Development – Single-Shaft

Configuration

Figure 4-3 Indicative Maximum Layout of the Proposed Development – Multi-Shaft

Configuration

Figure 4-4 Maximum Elevations of the Proposed Development – Single Shaft

Configuration

Figure 4-5 Maximum Elevations of the Proposed Development – Multi-Shaft

Configuration

Figure 4-6 Indicative 3D Visualisations of the Proposed Development Site

Figure 4-7 Access During Operation

Figure 5-1 Extend of Expected Land Raising

Figure 5-2 Laydown and Assess during Construction

Figure 5-3 Trenching Methods

Figure 5-4 Indicative Drawing of an Above Ground Electrical Cable Rack

Figure 5-5 Example Horizontal Directional Drilling (HDD)

Figure 6-1 Preliminary Indicative Layout, Including CCS Technology - April 2012

Figure 6-2 Interim Indicative Layout of the Proposed Development - March 2013

Figure 6-3 Interim Indicative Layout of the Proposed Development - August 2013

Figure 7-1 Cumulative Developments

Figure 10-1 Traffic Survey Locations

Figure 10-2 Crossing Points for the Proposed Route for Cooling Water Pipeline over

Roads and Public Rights of Way

Figure 11-1 Diffusion Tube Monitoring Locations

Figure 11-2 Modelled Mean Annual NOx Process Concentrations

Figure 12-1 Noise Monitoring and Receptor Locations

Figure 13-1 Distances from Seabank Substation

Figure 14-1 Significant Water Features and Catchment Boundary Map

Figure 15-1 Zone of Theoretical Visibility for the Proposed Development Site

Figure 15-2 HER Assets within 1km of the Proposed Development Site


May 2014

Figure 15-3a HER Assets within 1km of the Proposed Cooling Water Pipeline Corridor

Figure 15-3b HER Assets within 1km of the Proposed Cooling Water Pipeline Corridor

Figure 15-4 Location of Previous Investigations

Figure 15-5 Location of Previous Geotechnical Investigations

Figure 15-6 Geotechnical Transect from Previous Investigations

Figure 15-7a Geophysical Survey Results (2013)

Figure 15-7b Geophysical Survey Results with Single-Shaft Layout Overlaid

Figure 15-7c Geophysical Survey Results with Multi-Shaft Layout Overlaid

Figure 15-8 Location of Geotechnical Investigations

Figure 15-9 Geotechnical Transect from 2013 Investigations

Figure 15-10 Designated Assets within the 5km Study Area

Figure 15-11 Locations of Potential Below Ground Impacts (Single-Shaft)

Figure 15-12 Locations of Potential Below Ground Impacts (Multi-Shaft)

Figure 15-13a-e Areas of Previous Disturbance within the Other DCO Land

Figure 16-1 Statutory Nature Conservation Sites within 10km

Figure 16-2 Non-Statutory Nature Conservation Sites within 1km

Figure 16-3 Phase I Habitat Map Including BAP Habitats

Figure 17-1 Site Context and Registered Parks and Gardens

Figure 17-2 Topography

Figure 17-3 Site Character

Figure 17-4 Site Character Photographs A&B

Figure 17-5 Site Character Photographs C&D

Figure 17-6 Local Landscape Character Areas

Figure 17-7 Zones of Theoretical Visibility

Figure 17-8 Location of Representative Views and Photomontages

Figure 17-9 Representative Views 1&2





Figure 17-14 Representative View 11

Figure 17-15 Preliminary Landscape and Biodiversity Masterplan

Figure 17-16 Photomontage View 4 – Existing View

Figure 17-17 Photomontage of the Proposed Development from View Point 4, based on

a Single-Shaft configuration in Year 1




a Multi-Shaft configuration in Year 1



Figure 17-21 Photomontage View 10 – Existing View


May 2014









Figure 17-26 Photomontage of View Point 11 – Existing View









Seabank 3

PEI Report – Chapter 1 Introduction

1. Introduction

1.1. Background

1.1.1. This ‘Preliminary Environmental Information Report’ (PEI Report) has been prepared on behalf of SSE Seabank Land Investments Limited (the Applicant) in support of a proposed application that will be made to the Secretary of State (for Energy and Climate Change) under Section 37 of the Planning Act 2008 (Ref. 1-1), seeking an ‘Order’ granting Development Consent (a Development Consent Order, or DCO).

1.1.2. The DCO would provide the necessary authorisations and consents for the construction and operation of a generating station of up to 1,400 megawatts net electrical output capacity (MWe) (the ‘Proposed Development’) and associated infrastructure.

1.1.3. The Proposed Development is located on land adjacent to the existing Seabank 1 & 2 generating station in Severnside, Bristol, within the administrative boundary of South Gloucestershire Council (SGC). Elements of the Associated Development, in particular the proposed cooling water pipeline and electrical connection are situated within the administrative boundary of Bristol City Council (BCC).

1.2. The Applicant

1.2.1. The Applicant is SSE Seabank Land Investments Limited (SSE), which is a wholly owned subsidiary of SSE Generation Ltd.

1.2.2. SSE is one of the UK’s leading energy companies and the largest non-nuclear electricity generators, operating a diverse portfolio across the UK and Ireland. SSE is also a 50% shareholder of Seabank Power Ltd, which is the company that currently operates the existing Seabank 1 & 2 generating station.

1.2.3. Details of assets operated by SSE can be found at www.sse.com.

1.3. Location of the Proposed Development

1.3.1. The Proposed Development is known as ‘Seabank 3’ and is located on land immediately adjacent to the existing Seabank 1 & 2 generating station, approximately 5 kilometres (km) northeast of Avonmouth and 10km west of Bristol in an area called Crook’s Marsh in Severnside, as illustrated in Figure 1-1 (Volume III – Figures of this Report).

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Seabank 3


1.3.2. The proposed application site to which the DCO Application will apply (referred to in the remainder of this report as the ‘DCO Site’) comprises an area of approximately 38 hectares (ha) and constitutes:

• An area within which the proposed generating station and Carbon Capture Ready (CCR) sites will be situated (referred to together as the ‘Proposed Development Site’). The Proposed Development Site is approximately 19ha and lies wholly within the SGC administrative boundary and is fully owned by the Applicant; and

• Other DCO Land. This includes all Associated Development beyond the Proposed Development Site, which comprises the proposed electrical connection and a cooling water pipeline. This covers approximately 19ha and is the only part of the DCO Site that is situated within the administrative boundary of BCC.

1.3.3. A more comprehensive description of the DCO Site and the terminology mentioned above is presented in Chapter 3: The Site and Its Surroundings of this PEI Report.

1.4. The Proposed Development

1.4.1. The Proposed Development constitutes a generating station with up to 1,400MW net electrical output capacity. This comprises up to two Combined Cycle Gas Turbine (CCGT) units with a total capacity of up to 1,400MWe, plus peaking plant units with a capacity up to 240MWe. The electrical capacity of the CCGTs will be reduced if the peaking plant is built to ensure the total output capacity of the Proposed Development does not exceed 1,400MW.

1.4.2. The Proposed Development will include the installation of a hybrid cooling water system, administrative buildings and associated infrastructure, as well as Associated Development within the Proposed Development Site such as pipework, control rooms, water supply, storage and purification equipment, gas receiving equipment, grid connection infrastructure and supporting site infrastructure. The proposed cooling water pipeline and electrical connection are also Associated Development but referred to hereafter as ‘associated infrastructure’ so to distinguish these from the Proposed Development Site.

1.4.3. A more comprehensive description of the Proposed Development is presented in Chapter 4: Project Description of this PEI Report.

1.4.4. The need for the Proposed Development is outlined in Chapter 6: Project Need and Alternatives of this PEI Report, which also describes the alternatives that have been considered during the evolution of the Proposed Development.

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Seabank 3


1.5. Structure of this PEI Report

1.5.1. The following provides a summary of each document that forms the PEI Report:

• PEI Volume I – Main PEI Report: This document is the main body of the PEI Report, divided into a number of background and technical chapters supported with figures and tabular information for clarity of reading.

• PEI Volume II – Technical Appendices: This document comprises survey data, technical reports, and background information supporting the assessments within the PEI Report.

• PEI Volume III – Figures: This document contains the figures referred to in Volume I.

• PEI Non-Technical Summary: This is a separate document providing a concise summary of the Proposed Development and associated infrastructure, alternative designs that were considered, and the environmental effects and mitigation measures in plain, non-technical language.

1.5.2. A list of the PEI Report chapters and Appendices is presented in Chapter 7: Assessment Methodology.

1.6. The Purpose of the Preliminary Environmental Information (PEI) Report

1.6.1. The purpose of this PEI Report is outlined in The Planning Inspectorate Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4) (Ref. 1-2), where it is described as a document to “enable the local community to understand the environmental effects of the proposed development so as to inform their responses regarding the proposed development”.

1.6.2. PEI is defined in the Infrastructure Planning (Environmental Impact Assessment) Regulations 2009 (Ref. 1-3) as “information referred to in Part 1 of Schedule 4 (information for inclusion in environmental statements) which (a) has been compiled by the applicant; and (b) is reasonably required to assess the environmental effects of the development (and of any associated development)”.

1.6.3. In order to enable consultees to develop “an informed view of the project” this report presents preliminary findings of the environmental assessments undertaken to date. This allows consultees the opportunity to comment on the Proposed Development and associated infrastructure, the assessment process and preliminary findings prior to the finalisation of the Environmental Statement

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Seabank 3


(ES). The Applicant is actively seeking the views of consultees on the information contained within this report, and there is opportunity within the process for both the Environmental Impact Assessment (EIA) and the project design to take account of any comments received.

1.6.4. It should be noted that this PEI Report does not constitute a full ES, but rather presents the assessments completed as part of the EIA process to date. The various assessments are at differing stages of completion and any gaps are highlighted where relevant. It is considered that the information presented in this PEI Report is sufficient to enable consultees to develop an informed view of the project. Following the formal consultation process, and once the design is further developed this report will be developed into a final ES taking into consideration comments raised during the consultation.

1.6.5. The information presented in this report depicts the extent of the environmental assessment work undertaken to date based upon the information available. The design will continue to evolve and some baseline data are not yet available, although this is not considered to be material to understanding the potential effects of the Proposed Development and associated infrastructure. As such it is not possible to present a complete impact assessment on each environmental topic, but instead this report depicts what the likely effects are, based upon current information, and what work will be undertaken in the future to complete the individual assessments. Presentation of PEI in this way also allows the EIA process to take account of comments received during the formal consultation process.

1.6.6. Where data are missing or there are assumptions made for this preliminary assessment, this is made clear in the text of the report and the information will be made available in the final ES. The information provided within this report has been compiled in order to seek comments on the Proposed Development and associated infrastructure from the consultees. Comments will be taken into consideration during the final stages of the EIA process and project design.

1.7. Location of Information within the PEI Report

1.7.1. The EIA Regulations (Schedule 4, Part 1) (Ref. 1-3) identify information that is “reasonably required to assess the environmental effects of the development and which the applicant can, having regard in particular to current knowledge and methods of assessment, reasonably be required to compile”. This information together with its location within the PEI Report is presented in Table 1-1.

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Seabank 3 PEI Report – Chapter 1 Introduction

May 2014

Page 1-5

Table 1-1: Location of Information within the PEI Report

Specified Information (EIA Regulations)

Location Within PEI Report

1 Description of the development, including in particular: -

a) A description of the physical characteristics of the whole development and the land use requirements during the construction and operational phases;

Chapter 4: Project Description

b) A description of the main characteristics of the production processes, for instance, nature and quantity of the materials used; and


c) An estimate, by type and quantity, of expected residues and emissions (water, air and soil pollution, noise, vibration, light, heat, radiation, etc) resulting from the operation of the proposed development.

Chapters 9-19

2 An outline of the main alternatives studied by the applicant and an indication of the main reasons for its choice, taking into account the environmental effects.

Chapter 6: Project Need and Alternatives

3 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, material assets, including the architectural and archaeological heritage, landscape and the inter-relationship between the above factors.

Chapters 9-19

4 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, resulting from:

Chapters 9-19

a) the existence of the development; Chapters 9-19

b) the use of natural resources; and Chapters 9-19

c) the emission of pollutants, the creation of nuisances and the elimination of waste.

Chapter 11: Air Quality

Chapter 12: Noise and Vibration

5 A description of the measures envisaged to prevent, reduce and where possible, off set any significant adverse effects on the environment.

Chapters 9-19

6 A non-technical summary of the information provided under paragraphs 1 to 5 of this Table.

Non-Technical Summary

7 An indication of any difficulties (technical deficiencies or lack of know-how) encountered by the applicant in compiling the required information.

Chapter 7: Assessment Methodology

1.8. Other Required Consents

1.8.1. The Proposed Development and associated infrastructure will require an

Environmental Permit under the Environmental Permitting (England and Wales)

Regulations 2010, as amended (Ref. 1-4). This Permit will be subject to

determination by the Environment Agency (EA). It is intended that an application

for an Environmental Permit will be submitted to the EA within similar timescales

as the DCO Application, and it is noted that there are overlaps in consideration

between the two consenting regimes. This PEI Report has considered all

potential environmental effects of the Proposed Development and associated

infrastructure (as will the final ES), and will therefore also inform and support the

Environmental Permitting process.

Seabank 3


1.8.2. Additional consents may be required to support the Proposed Development and those that are to be covered by the DCO will be highlighted in the application accordingly.

1.9. References

Ref. 1-1 HMSO, IPC (2008); The Planning Act, Infrastructure Planning Commission (IPC)

Ref. 1-2 Planning Inspectorate (2013); Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4)

Ref. 1-3 HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations

Ref. 1-4 Environmental Permit under the Environmental Permitting (England and Wales) Regulations 2010

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Seabank 3 PEI Report – Chapter 2 The DCO and EIA Processes

May 2014 Page 2-1

2. The DCO and EIA Processes

2.1. Introduction

2.1.1. This chapter of the PEI Report outlines the purpose of PEI and the process

involved within the Application.

2.1.2. It also presents a review of the key issues raised by consultees during the

Scoping stage and indicates how and where these issues have been addressed

within this PEI Report.

2.2. DCO Process

2.2.1. The Proposed Development falls within the definition of a ‘Nationally Significant

Infrastructure Project’ (NSIP) under Section 14(1)(a) and Sections 15(2) of the

Planning Act 2008 (Ref. 2-1), as it is an onshore generating station within

England that will have a generating capacity greater than 50MW gross output. As

such there is a requirement to submit an application for development consent for

the Proposed Development to the Planning Inspectorate.

2.2.2. As a NSIP project, the Applicant is required to seek a DCO to build the Proposed

Development, under Section 31 of the Planning Act. The DCO Application will be

prepared in accordance with Section 37 of this Act and secondary legislation,

including The Infrastructure Planning (Environmental Impact Assessment)

Regulations 2009 (as amended) (‘EIA Regulations’) (Ref. 2-2) and Regulation 5

(2)(a) of the Infrastructure Planning (Applications: Prescribed Forms and

Procedure) Regulations 2009 (‘APFP Regulations’) (Ref. 2-3).

2.2.3. The DCO Application will be submitted to the Planning Inspectorate’s National

Infrastructure Directorate who will examine the application and make

recommendations to the Secretary of State, who in turn will determine whether or

not a DCO should be granted for the Proposed Development and associated

infrastructure. Development Consent is granted by means of a parliamentary

‘Order’ (the DCO).

2.2.4. A DCO can grant planning permission and a range of other consents and

authorisations for the ‘Principal Development’ and ‘Associated Development’. The

latter is either to support the construction or operation of or help to address the

impacts of the former, such as the proposed cooling water pipeline for example.

2.2.5. It is currently anticipated that the Application for Development Consent will be

submitted in Quarter 4 (Q4) of 2014, although this may be subject to change.


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2.3. EIA Development

2.3.1. As outlined above the proposals fall within the definition of a NSIP under the

definition of the Planning Act 2008 (Ref 2-1). It is also a ‘Schedule 1’

development under Schedule 1 (2)(a) of the EIA Regulations (Ref. 2-2) as it

constitutes “Thermal power stations and other combustion installations with a

heat output of 300 megawatts or more”. The Proposed Development is therefore

classified as a mandatory EIA development and as such an ES needs to be

prepared to comply with the EIA Regulations.

Legislation and Guidance for EIA and Preparation of an ES

2.3.2. The PEI Report has been (and the final ES will be) prepared in accordance with

applicable legislation, guidance, and case law for the preparation of such

documents as outlined below.

2.3.3. The Planning Act 2008 (Ref. 2-1) enables the Secretary of State to designate

National Policy Statements (NPSs), to set out national policy in relation to

specified descriptions of nationally significant infrastructure development. A

number of NPSs relating to energy infrastructure (including technology specific

NPSs) were designated by the Secretary of State for the Department of Energy

and Climate Change (DECC) in July 2011.

2.3.4. As outlined in Chapter 8: Planning Policy Context, the NPSs that are relevant to

the Proposed Development are the:

• Overarching NPS for Energy (EN-1) (Ref. 2-4);

• Fossil Fuel Electricity Generating Infrastructure NPS (EN-2) (Ref. 2-5);

and

• NPS for Electricity Networks Infrastructure (EN-5) (Ref. 2-6).

2.3.5. In addition to the NPS, particular advice on the EIA process for DCO applications

is provided by several advice notes published by the Planning Inspectorate,

whilst further useful advice is afforded by Planning Practice Guidance (Ref 2-7)

and the guidance contained within the Department for Communities and Local

Government (DCLG) paper ‘Environmental Impact Assessment: A guide to good

practice and procedures, a consultation paper’ (2006) (Ref 2-8).

2.3.6. In preparing this PEI Report (in line with the regulations as it forms part of the EIA

process), reference has been made to the following policies and guidance:

• The Planning Act (2008) (Ref. 2-1);


May 2014 Page 2-3

• Infrastructure Planning (Environmental Impact Assessment)

Regulations (2009) (Ref. 2-2);

• Planning Inspectorate - Advice Note 3: EIA Consultation and

Notification; July 2013 (Ref. 2-9);

• Planning Inspectorate - Advice Note 7: Environmental Impact

Assessment, Screening and Scoping; July 2013 (Ref. 2-10);

• Planning Inspectorate - Advice Note 9: Rochdale Envelope; July 2013

(Ref. 2-11);

• DECC Overarching NPS for Energy (EN-1) (2011) (Ref. 2-4);

• DECC NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2)

(2011) (Ref. 2-5);

• DECC NPS for Electricity Networks Infrastructure (EN-5) (2011) (Ref.

2-6);

• DCLG Planning Practice Guidance (Ref. 2-7);

• DCLG 2006. Environmental Impact Assessment: A guide to good

practice and procedures (Ref. 2-8);

• Institute of Environmental Management and Assessment (IEMA) 2006.

Guidelines for Environmental Impact Assessment (Ref. 2-12);

• Environment Agency 2002 – Scoping Guidance on the Environmental

Impact Assessment of Projects (Ref. 2-13).

2.4. The EIA Scoping Exercise

2.4.1. Before preparing an EIA, an applicant has the opportunity to ask the Secretary of

State for a formal written opinion on the information to be included in the ES. This

is known as a ‘Scoping Opinion’. By this means key stakeholder engagement and

consultation can begin at an early stage in the process.

2.4.2. EIA scoping refers to the activity of identifying those environmental aspects that

may be significantly affected by the construction and operation of the Proposed

Development and associated infrastructure and how those effects are to be

assessed within the EIA process. In addition, it presents the justification for the

exclusion of those aspects that are considered will be unaffected by the

Proposed Development. In doing so, the potential significance of effects

associated with each environmental aspect becomes more clearly defined,

resulting in the identification of priority issues to be addressed in the EIA. This

process therefore focuses the assessment on the critical issues that require

assessment within the consenting process.


May 2014 Page 2-4

2.4.3. The issues to be addressed within the ES were identified in the EIA Scoping

Report submitted to the Planning Inspectorate on 12 February 2013 (Ref. 2-14)

together with a request for an EIA Scoping Opinion under Regulation 8(1) of the

EIA Regulations. This Scoping Report was developed following initial consultation

with a number of statutory consultees and was informed by experience from the

Seabank 1 & 2 station. A Scoping Opinion was received on 19 March 2013 (Ref.

2-15). Key issues raised in the Scoping Opinion relevant to the technical

assessments are summarised at the start of each technical chapter in this report

(Chapter 9-19 of this PEI Report) and have been taken into account during the

EIA process and in the completion of this PEI Report.

2.4.4. Formal EIA Scoping Responses received from the Secretary of State on the EIA

Scoping Report are presented in Appendix A, Volume II of this PEI Report.

2.4.5. The topics included within this PEI Report reflect the topics that will be presented

within the final ES. An additional chapter has been included in this report

compared with the suggested structure presented in the Scoping Report following

the response from the Health Protection Agency (HPA), which recommended that

“health impacts are consolidated into a separate chapter of the ES or carried out

as a separate HIA”.

2.4.6. The Scoping Opinion from the Secretary of State also recommends a separate

chapter on Infrastructure and Utilities, to assess the effect of the Proposed

Development on 3rd party assets. The need for a separate chapter has largely

been superseded by design avoidance measures however, which are in-built into

the Proposed Development. Sections 3.3 and 3.6 of Chapter 3: The Site and Its

Surroundings present an overview of the utilities and infrastructure onsite and in

the surrounding area. Sections 5.2 and 5.3 of Chapter 5: Enabling Works and

Construction discuss the diversion of existing infrastructure and services within

the Proposed Development Site and special crossing of any infrastructure and

services required by the proposed cooling water pipeline. Any residual effects on

environmental parameters are discussed within the individual technical chapters.

2.4.7. Where it has not yet been possible to complete an assessment for a topic to date,

the topic is still included in this report, setting out details of what will be assessed

with an initial prediction of the likely effects.

2.5. Non Key Issues

2.5.1. The Scoping process concluded that the following technical topics are not

relevant to the EIA for the Proposed Development and could be scoped-out from

further evaluation. It is therefore intended that these topics will not be assessed

within the ES, though comments on these topics are invited from consultees.


May 2014 Page 2-5

Aviation

2.5.2. Consultation with the Civil Aviation Association (CAA) during scoping confirmed

that there is no legislative requirement to illuminate structures or obstacles below

150m in height. However, the CAA suggested contacting the surrounding

aerodrome license holders regarding safeguarding. This includes the Bristol

International Airport (Lulsgate) and the former Filton Airport (currently closed but

with emergency helicopters operating out of this site).

2.5.3. Bristol International (Lulsgate) confirmed that the Proposed Development falls

outside the airport’s formally safeguarded area of 15km; therefore it does not

have safeguarding concerns with the Proposed Development.

2.5.4. Emergency helicopter services (Police and Ambulance) agreed that there is no

legal requirement to illuminate the structures for the height of the proposed

stacks (up to 100m at the time of Scoping). However, due to the distance to Filton

Airport, both the Police and Ambulance Air Services consider it to be desirable to

have night time lighting and reasonable visual contrast of the stacks during

daylight hours.

2.5.5. In light of this feedback, the Proposed Development will incorporate low intensity

steady red aviation warning lighting and colour markings positioned as close to

the top of the stacks as practicable. This is further outlined in Chapter 4: Project

Description of this PEI Report and assessed in Chapter 17: Landscape and

Visual.

2.5.6. Bearing this in mind, it is not considered that an aviation assessment is required

for the PEI Report or final ES.

Electronic Interference

2.5.7. The Scoping Opinion from the Secretary of State agreed that Electronic

Interference effects could be scoped out of the EIA, providing that a screening

assessment was undertaken.

2.5.8. A screening assessment by ‘Tom Paxton’ Broadcasting Consultant indicates that

the Severnside area receives its preferred terrestrial signals from the Mendip

transmitter, sited about 34km due south of the Proposed Development Site. It is

therefore predicted that any 'shadow' (on electronic reception) cast by the

Proposed Development will lie to the north, in the direction of Severn Beach

village.

2.5.9. The nearest housing in this direction is almost exactly 1.5km away, at the

southern edge of Severn Beach. At this distance, it is not expected that the

shadows from main structures on Proposed Development Site would reach the


May 2014 Page 2-6

Severn Beach village, and the stacks should not cause any interference due to

their relatively narrow width (which enables the signal to diffract around these

structures). Tom Paxton Broadcasting Consultant concluded that a full

assessment would not be necessary and the potential effects from electronic

interference can be considered insignificant/negligible.

2.5.10. A copy of the screening assessment is presented in Appendix A, Volume II of this

PEI Report.

Accidental Events/Health and Safety

2.5.11. The majority of emergency response plans and contingency measures will be

dealt with in the construction and Environmental Permits that will be required for

the construction and operation of the Proposed Development and associated

infrastructure. However, the potential for effects of air emissions on human health

are considered as part of the EIA and in this PEI Report.

Soils and Agriculture

2.5.12. The Proposed Development Site is not currently used for agricultural purposes

and lies within a wider employment area which benefits from planning

permissions for warehousing and distribution uses. It also has extant planning

permission for a range of industrial uses (excluding a generating station) as well

as being part of a wider area that has been allocated for a range of employment

uses including energy generation in the SGC Core Strategy (Ref. 2-17). It is

therefore not considered that an assessment of agricultural land use or its

potential for crop production is relevant to the Proposed Development Site.

2.5.13. Furthermore the Agricultural Land Classification Map South West Region (Ref. 2-

19) and Natural England MAGIC map (Post 1988 Agricultural Land Classification)

(Ref. 2-18) both classify the Proposed Development Site as predominantly

industrial use. The nearest agricultural land is classed as Grade 3b (Moderate

Quality) or 4 (Poor Quality); hence it is considered unlikely that the Proposed

Development would represent a significant loss of agricultural land.

2.6. Preliminary Environmental Information

2.6.1. As part of the EIA process, the assessment of the potential environmental effects

on the various potential receptors is on-going. The assessments are at various

stages depending on the information that is currently available and the extent of

any investigations or site surveys that have been undertaken to date. A number

of surveys are either underway or still to be commissioned.

2.6.2. When further data becomes available after the production of this report, it will be

used to further inform the assessments, as they are developed for the final ES.


May 2014 Page 2-7

The information presented within this report is therefore in the form of initial

findings. This is subject to change should further data become available or upon

receipt of relevant consultation responses and any further changes arising

through the design process.

2.6.3. Each technical assessment that has been carried out highlights any current data

gaps and details the methodology that will be employed following receipt of the

relevant data.

2.6.4. Additional information received, along with the responses from the consultation

process, will be used to inform the design process and the final ES. Any changes

that arise between the production of this PEI Report and the final ES will be

highlighted and clearly explained within the final ES.

2.6.5. In particular, the description of baseline conditions in this PEI Report has been

based on the state of the Proposed Development Site as it was on 01 December

2013, which was valid at the time of drafting this report. The Site has undergone

noticeable change since this date, due to the introduction of a temporary access

route (haul road) for use by SITA to facilitate the construction of the Severnside

Energy Recovery Centre on land immediately west of the Proposed Development

Site, and also the construction of the Spine Access Road and new channel for

the Red Rhine along the northern boundary of the Proposed Development Site

on behalf of Severnside Distribution Land Ltd. A brief description of these other

developments is presented in Chapter 7: Assessment Methodology.

2.6.6. The site description and baseline conditions will be updated for the final ES, to

reflect the state of the Proposed Development Site at the point of submitting the

Application, or at an agreed point in time shortly beforehand. Any changes to the

predicted effects and mitigation measures due to the change in baseline

conditions would also be captured in the final ES.

2.7. Design Parameters Used within the DCO Application

2.7.1. A number of the detailed design aspects of the Proposed Development cannot be

fixed until the contract for the detailed design and construction of the Proposed

Development has been awarded. For example, the scale of the buildings within

the Proposed Development may vary depending upon the contractor appointed

and their specific selection and configuration of the plant and process equipment.

The design of the Proposed Development therefore needs to incorporate a

degree of flexibility to allow for such circumstances.

2.7.2. In order to ensure a robust assessment of the likely significant environmental

effects of the Proposed Development, the EIA will be undertaken adopting the

principles of the ‘Rochdale Envelope’ (Ref. 2-9). This will involve assessing the


May 2014 Page 2-8

maximum and minimum parameters for the elements where flexibility needs to be

retained. Where this approach is applied to the specific aspects of the EIA this

has been confirmed within the relevant chapters of this PEI Report and will also

be confirmed within the relevant chapters of the ES that will report on the

complete findings of the EIA and form part of the DCO Application.

2.7.3. For the purposes of the assessments within this PEI Report, each chapter has

adopted a reasonable ‘worst-case’ scenario for its assessment. For the majority

of assessments, this worst-case will be based upon the maximum design

parameters, though it is recognised that the final design will be very unlikely to

utilise the maxima for every building as it depends on the plant selected and the

layout; therefore this is considered to be a highly conservative assumption. This

is discussed in Chapter 4: Project Description.

2.8. Consultation

2.8.1. The process of consultation is integral to the DCO Application and EIA processes

and important to the development of a comprehensive and balanced EIA of the

Proposed Development. The views of interested parties including key statutory

and non-statutory consultees serve to focus the environmental studies and to

identify specific issues, which require further investigation. Consultation is also an

on-going process, which enables mitigation measures to be incorporated into the

project design, thereby limiting adverse effects and enhancing benefits.

2.8.2. The Planning Act (Ref. 2-1) requires applicants for Development Consent to carry

out formal (statutory) consultation on their proposals prior to submitting an

application (during the pre-application stage).

2.8.3. Section 42 of the Planning Act requires an applicant to consult with ‘prescribed

persons’, which includes certain statutory consultees such as the EA and Natural

England (NE), relevant statutory undertakers, relevant local authorities, those

with an interest in the land, and those who may be affected by the development.

The PEI is generally provided to the ‘prescribed persons’ as part of the Section

42 consultation.

2.8.4. Section 47 requires an applicant to consult with the local community on the

development. Prior to this, the applicant must agree a Statement of Community

Consultation (SoCC) with the relevant local authority. The SoCC must set out the

proposed community consultation and, once agreed with the relevant local

authority, the SoCC notice must be published in local newspapers circulating

within the vicinity of the DCO Site. The community consultation must then take

place in accordance with the SoCC. It recommends that the PEI is made

available to the community and that it includes a non-technical summary. In

addition, Section 48 of the Act requires the applicant to publicise the proposed


May 2014 Page 2-9

application in the prescribed manner in a national newspaper, The London

Gazette and local newspapers circulating within the vicinity of the land.

2.8.5. The consultation that the Applicant has undertaken to date and is in the process

of undertaking is summarised below:

• Informal consultation - this has encompassed a number of meetings

with SGC, BCC, NE, EA, Highways Agency (HA), English Heritage and

other relevant authorities and statutory consultees; informal

consultation with the local community within the vicinity of the DCO

Site from June 2013, including a number of public exhibitions; and

informal consultation with the relevant local authorities on the

preparation of the SoCC and the proposed community consultation for

Section 47. Comments received during the informal consultation will be

afforded the same weight as those received during the formal

consultation.

• EIA related consultation - this has taken place alongside the ‘informal

consultation’ and has included initial meetings and discussions with the

technical departments of the relevant local authorities and statutory

consultees mentioned above to inform early environmental assessment

work. Consultation was also undertaken during the preparation of the

EIA Scoping Report to form the basis of the application made to the

Planning Inspectorate for a Scoping Opinion. Further discussions were

held with relevant consultees following receipt of the Scoping Opinion

to inform the preparation of this PEI Report. EIA related consultation

will continue through the formal (statutory) consultation stage.

• Formal (statutory) consultation expected to be held in Spring 2014,

which will comprise:

o Section 42 consultation of ‘prescribed persons’;

o Section 47 consultation of the local community; and

o Section 48 publicity and related notification of those consulted by

the Planning Inspectorate during the EIA scoping process.

2.8.6. This PEI Report forms part of the information that is being provided for the

purposes of the formal (statutory) consultation pursuant to Sections 42, 47 and

48 of the Planning Act. It is intended to inform the ‘prescribed persons’ and local

community on the following:

• The extent of the environmental assessment work performed to date

on the Proposed Development and associated infrastructure;


May 2014 Page 2-10

• Work that has been completed, or is underway, to address issues

raised during the informal consultation and EIA scoping stages that are

of relevance to the EIA process; and

• Any changes that have been made following the consultation

undertaken.

2.8.7. Responses received to the formal (statutory) consultation will be recorded

alongside those received through the informal consultation. The consultation that

has been undertaken and how this has informed the final design of the Proposed

Development and associated infrastructure will be fully documented within a

Consultation Report that will form part of the DCO Application.

2.8.8. All the information displayed at exhibitions is available via the website:

www.sse.com/seabank3.

2.9. PEI Report Availability

2.9.1. This PEI Report is available for viewing by the general public during normal office

hours at the offices of the Planning Department of SGC and BCC. Comments on

the planning application should be forwarded to the following address:

Jeffrey Penfold

The Planning Inspectorate

Temple Quay House

Temple Quay

Bristol

BS1 6PN

2.9.2. A copy is also being made available to view at the following addresses during a

public consultation period that is expected to be held in Spring 2014:

• Severn Beach Public Library / Post Office;

• Yate Public Library;

• Thornbury Library St Mary Street;

• The Patchway Hub;

• Bristol City Council City Office;

• Bristol City Council Customer Service Centre;

• Avonmouth Public Library;

• Sea Mills Public Library;

• Shirehampton Public Library; and


May 2014 Page 2-11

• Hendbury Public Library Crow Lane.

2.9.3. Further copies of all these reports, or further information on the Proposed

Development and associated infrastructure, can be obtained from the Applicant’s

website at: www.sse.com/seabank3

2.9.4. Printed copies of the full PEI Report and Technical Appendices can be

purchased for £350 (PEI Report £150, Technical Appendices £200), and

electronic copies on CD are available for free (or a fee of £5 each if requesting

more than 5 CDs) from:

Jade Fearon

SSE

Community Liaison Officer

FREEPOST SEABANK 3 CONSULTATION

2.10. References

Ref. 2-1. HMSO, IPC (2008); The Planning Act, Infrastructure Planning Commission (IPC)

Ref. 2-2. HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations

Ref. 2-3. HMSO (2009); Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations

Ref. 2-4. DECC (2011) Overarching NPS for Energy (EN-1)

Ref. 2-5. DECC (2011) NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2)

Ref. 2-6. DECC (2011) NPS for Electricity Networks Infrastructure (EN-5)

Ref. 2-7. DCLG (2014); Planning Practice Guidance. http://planningguidance.planningportal.gov.uk/blog/guidance/

Ref. 2-8. DCLG (2006); Environmental Impact Assessment: A guide to good practice and procedures.

Ref. 2-9. Planning Inspectorate (2013); Advice Note 3: EIA Consultation and Notification

Ref. 2-10. Planning Inspectorate (2013); Advice Note 7: Environmental Impact Assessment: Screening, Scoping and Preliminary Environmental Information (Version 4)

Ref. 2-11. Planning Inspectorate (2013); Advice Note 9: Rochdale Envelope

Ref. 2-12. IEMA (2006); ‘Guidelines for Environmental Impact Assessment’.

Ref. 2-13. Environment Agency (2002) Scoping Guidance on the Environmental Impact Assessment of Projects.

Ref. 2-14. URS Infrastructure & Environment UK Limited on behalf of SSE Generation Ltd (2013); ‘Seabank 3 EIA Scoping Report’.

Ref. 2-15. Planning Inspectorate (2013); ‘Formal Scoping Opinion regarding the Proposed Seabank 3 CCGT’.


May 2014 Page 2-12

Ref. 2-16. South Gloucestershire Council (2013) Core Strategy

Ref. 2-17. Natural England (2013) South West Region Agricultural Land Classification

Ref. 2-18. Natural England MAGIC map (2013) (Post 1988 Agricultural Land Classification)

Seabank 3

PEI Report – Chapter 3 The Site and Its Surroundings

3. The Site and its Surroundings

3.1. Introduction

3.1.1. This chapter provides an overview of the DCO Site and its surroundings, based on its status pre-01 December 2013 (as explained in Chapter 2: The DCO and EIA Process). A description of the project is presented in Chapter 4: Project Description.

3.1.2. The DCO Site comprises an area of approximately 38ha and constitutes the following two components:

1. The ‘Proposed Development Site’ - an area of approximately 19ha (illustrated on Figure 3-1, Volume III of this PEI Report) situated immediately east of the existing Seabank 1 & 2 station and wholly located within the administrative boundary of SGC. It is bound by the proposed SITA Severnside Energy Recovery Centre (SERC) to the northwest, beyond which is the Severn Estuary, approximately 400m to the west (an internationally designated Special Area of Conservation, Special Protection Area, Ramsar Site and Site of Special Scientific Interest), the former Terra Nitrogen and ICI site to the north which is now vacant land, an existing roundabout that will form part of the proposed Spine Access Road to the east (beyond which is grass fields), and grass fields and the Avonmouth LNG Storage Facility to the south. The administrative boundary of BCC forms the southern boundary of the Proposed Development Site.

The Proposed Development Site is further split into the following land parcels, as illustrated in Figure 3-1 (Volume III of this PEI Report). The areas overlap slightly, resulting in the sum of the three components being slightly greater than the 19ha Proposed Development Site.

• Generating Station Site: an area of approximately 7.4ha within the western part of the Proposed Development Site, within which the generating station and some Associated Development will be constructed. It excludes the land parcels described below.

• Utilities, Services and Landscaping Area: this is a 6.4ha area reserved for utilities connections, gas reception and landscaping, excluding the electrical connection and cooling water pipeline.

• CCR Site: an area of approximately 6.3ha within the eastern part of the Proposed Development Site which is reserved for the future retrofit of Carbon Capture Storage (CCS) plant should this be required. CCS is not part of this application; however this land will be retained for the installation of post combustion carbon capture,

May 2014 Page 3-1

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cleaning and compression plant if the technology becomes viable. Should CCS be developed for the generating station at some point in the future, this would be subject to a new planning application. In accordance with the CCR requirements outlined by DECC, this land has been set aside in order to satisfy the Secretary of State that it can be used as and when installing CCS technology. The CCR Site will be used by construction contractors during the construction of the generating station, as described in Chapter 5: Enabling Works and Construction, and reinstated to grassland following its completion.

2. Other DCO Land: This includes all Associated Development (as defined by Section 115(2) of the Planning Act) beyond the Proposed Development Site, which consists of the proposed electrical connection and proposed cooling water pipeline. It covers approximately 19ha and is situated entirely within the administrative boundary of BCC.

3.1.3. The DCO Site and its land parcels outlined above are illustrated in Figure 3-1 (Volume III of this PEI Report). The Proposed Development Site and Other DCO Land are described separately below, in Sections 3.2 and 3.6 respectively.

3.2. The Proposed Development Site

3.2.1. The Proposed Development Site (‘the Site’) is situated within the Severn Estuary, approximately 5km northeast of Avonmouth and 10km west of Bristol in an area called Crook’s Marsh in Severnside, as illustrated in Figure 1-1, Volume III of this PEI Report. It is located entirely within SGC, with its southern boundary forming the administrative boundary with BCC.

3.2.2. The Site covers an area of approximately 19ha and is located on land immediately adjacent to the existing Seabank 1 & 2 CCGT Power Station within a predominantly industrial area. The River Severn lies approximately 400m to the west and the M49 motorway 1km to the east of the Site. The approximate National Grid Reference of the centre of the Proposed Development Site is (x,y) 354300, 182130.

3.2.3. The Proposed Development Site constitutes a relatively flat area of open, uneven grassland ranging in level between 5.5m and 7m above ordnance datum (AOD), with the existing access to the Proposed Development Site via Ableton Lane, from Severn Road.

3.2.4. Figure 3-2 (Volume III of this PEI Report) presents an aerial image of the Proposed Development Site. It shows that the Site is criss-crossed by several rhines (drainage channels) and ditches that flow into the Severn Estuary via the Red Rhine. The Red Rhine is the largest drainage channel within the Proposed

May 2014 Page 3-2

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Development Site and one of the main rhines in this area, currently running in an east to west direction along the south of the CCR Site, and then through the centre of the Generating Station Site. There are proposals being developed by a third party (Severnside Distribution Land Ltd), which are separate to this Application, to relocate the Red Rhine along the northern edge of the Proposed Development Site under the extant 1957/58 planning consent for this part of Severnside. This is described further in Chapter 7: Assessment Methodology. At the time of writing, this work is expected to be completed in early 2015.

3.2.5. A secondary rhine is currently located to the south of the Proposed Development Site, which serves as a main tributary to the Red Rhine. This runs across land known as ‘Crook’s Marsh’ in a south to north direction, and is hereafter referred to as the ‘Crook’s Marsh Stream’.

3.2.6. Shrub vegetation on the Proposed Development Site is limited and mainly concentrated to the entrance/egress to/from Ableton Lane and along the rhines. There are currently no buildings or structures onsite. Some small mature ash trees are located approximately in the centre of the Generating Station Site adjacent to the northeast bank of the Red Rhine. None of the trees onsite has tree preservation orders (TPOs) and they are considered to be in poor condition (see Chapter 16: Ecology).

3.2.7. There are 5 electricity pylons and associated 400 kilovolt (kV), 132kV and 11kV overhead lines (OHLs) located within the CCR Site. The 11kV and 400kV lines cross the Generation Station Site in the southeast corner. The two 132kV lines have recently been decommissioned by Western Power Distribution.

3.2.8. There are redundant railway tracks immediately north of the Generation Station Site and within the northwest corner of the Proposed Development Site. This former railway line branches off the Severn Beach line and heads via a tunnel under the A403 towards Severnside works, although it is no longer functional. There is a fence line currently separating the redundant railway track from the rest of the Proposed Development Site, as shown in Figure 3-2 (Volume III of this PEI Report). This fence line also acts as a barrier between the Proposed Development Site and the adjacent former Terra Nitrogen and ICI site.

3.2.9. A number of dirt tracks cross the Proposed Development Site currently to provide access to the electricity pylons. These are private tracks and run from Ableton Lane, crossing the Red Rhine to the northern boundary and then along the northern boundary of the Proposed Development Site in a southerly direction.

3.2.10. There is an existing Public Right of Way (PROW) located immediately south of the Proposed Development Site in Crook’s Marsh, which terminates at the southern Site boundary, as illustrated in Figure 3-2 (Volume III of this PEI Report). No PROWs currently cross the Proposed Development Site.

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3.2.11. The following figures present a series of photographs of the Proposed Development Site and nearby surroundings at the time of drafting this PEI Report (pre-01 December 2013). The existing site conditions are shown to be predominantly open grassland with scattered shrub:

• Plate 3-1 [Photo Number 1] - shows the Red Rhine from the Utilities, Services and Landscaping Area, just south of the CCR Site. This is looking in a westerly direction showing Seabank 1 & 2 in the background and the existing OHLs dissecting the CCR Site.

• Plate 3-2 [Photo Number 2] - taken from the Generating Station Site and showing a closer view of Seabank 1 & 2.

• Plate 3-3 [Photo Number 3] - a photograph facing northeast from the Generating Station Site towards the redundant railway tracks and the former Terra Nitrogen and ICI site.

• Plate 3-4 [Photo Number 4] – shows the existing trees onsite, looking in a southeasterly direction facing towards the CCR Site.

• Plate 3-5 [Photo Number 5] – shows the Red Rhine within the CCR Site, facing south towards the nearby Avonmouth LNG Storage Facility, which is discussed further later in this chapter.

• Plate 3-6 [Photo Number 6] - a photograph taken facing north from the centre of the CCR Site. This shows the existing OHLs which cross the CCR Site in a northeast to southwest direction to Seabank Substation.

3.2.12. The location and direction of where the photographs were taken provided are illustrated in Figure 3-2 (Volume III of this PEI Report).

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Seabank 3


Plate 3-1: Photograph 1 from the centre of the Proposed Development Site, facing west towards Seabank 1 & 2 [Date taken, 04/07/2013]

Plate 3-2: Photograph 2 from the Centre of the Generating Station Site, facing West towards Seabank 1 & 2 [Date taken, 01/07/2013]

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Plate 3-3: Photograph 3 from the Generating Station Site, facing Northeast towards the redundant railway tracks. [Date taken, 01/07/2013]

Plate 3-4: Photograph 4 from the Generating Station Site, facing Southeast and showing the existing trees [Date taken, 01/07/2013]

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Plate 3-5: Photograph 5 from the CCR Site adjacent to the Red Rhine, facing East [Date taken, 30/08/2012]

Plate 3-6: Photograph 6 from the Centre of the CCR Site, facing North [Date taken, 30/08/2012]

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3.3. Existing Services within the Proposed Development Site

3.3.1. A number of existing buried and above ground services are present on the Proposed Development Site. A description of these is provided below and is illustrated in Figure 3-3 (Volume III of this PEI Report).

Gas Pipelines

3.3.2. There are two natural gas pipelines currently supplying Seabank 1 & 2, which are partly located within the Proposed Development Site: a 42 inch (”) (1,050mm) diameter gas pipeline owned by Seabank Power Limited, which transports gas from Abson to Severnside (known as the ‘Abson pipeline’); and an 18” (450mm) pipeline owned by National Grid Gas (known as ‘Feeder 14’). Both of these pipelines run beneath the Proposed Development Site adjacent to the southern boundary, as shown in Figure 3-3 (Volume III of this PEI Report).

3.3.3. The Feeder 14 pipeline has an off-take supplying the National Transmission System (NTS) within the Seabank 1 & 2 gas receiving station. National Grid currently provides a gas capacity of 19.1 gigawatt hours per day (GWh/day), which is sufficient to meet the base load fuel demand for Seabank 2 of 18.7 GWh/day (the Abson pipeline can feed Seabank 1). The Feeder 14 line runs from the southeast of the Proposed Development Site along the southern boundary (within the Proposed Development Site) to the Seabank 1 & 2 gas receiving station (see Figure 3-3, Volume III of this PEI Report). It rises above ground as soon as it enters the Seabank 1 & 2 site, before terminating at an Above Ground Installation (AGI) owned by National Grid Gas within the Seabank 1 & 2 station.

3.3.4. The Abson pipeline runs from the southeast corner of the Proposed Development Site and crosses to the southwest corner, before coming above ground in the northeast corner of the existing Seabank 1 & 2 station. This pipeline runs through areas designated for development under this application and will need diverting as part of the Proposed Development, as described in Chapter 5: Enabling Works and Construction.

3.3.5. There is also a third gas pipeline owned by Wales & West Utilities that runs through the southeast boundary of the Generation Station Site in a southeast to northwest direction. This pipeline is located within the Utilities, Services and Landscaping Area and therefore should not require diverting.

Water Pipelines

3.3.6. A 24” (600mm) water main owned by Bristol Water is located within the Proposed Development Site and runs along its southern Site boundary. Bristol Water requires an easement strip of 5m either side of the pipeline, however this will not

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directly impact on the Proposed Development as it is located within the Utilities, Services and Landscaping Area.

3.3.7. A private water pipeline runs also north to south across the Generating Station Site to supply the industrial estate to the derelict Terra Nitrogen and ICI site to the north. This redundant private water pipeline crosses the 24” water main and will require decommissioning or diverting as part of the enabling works for the Proposed Development.

3.3.8. Seabank 1 & 2 is connected to Wessex Water’s Bristol Waste Water Treatment Works (WWTW), which is located approximately 3.5km south of the Proposed Development Site, via two existing pipelines: a 500mm supply pipe and a 350mm return, both of which are maintained and operated by Wessex Water Ltd. These pipelines do not currently extend onto the Proposed Development Site and terminate at a receiving station on the western side of the Seabank 1 & 2 station.

Overhead Electrical Lines (OHLs)

3.3.9. There are currently 400kV, 132kV and 11kV OHLs crossing the CCR Site in an east to west direction, and with five pylons on the CCR Site. Figure 3-3 (Volume III of this PEI Report) illustrates the locations of these OHLs. These lines do not need diverting to enable the Proposed Development, with the exception of the 11kV line, which will be diverted underground as described in Chapter 5: Enabling Works and Construction.

3.4. Proposed Development Site History

3.4.1. The Proposed Development Site has generally remained grassland since the first published map in 1886, with the exception being the addition of field boundaries, hedges, the Red Rhine, a railway track, and more recently, electricity pylons.

3.4.2. Post 1955, a series of ‘works’ were built in the area surrounding the DCO Site under the extant 1957/58 consent, including the introduction of the railway tracks running north to east along the northern boundary of the Proposed Development Site. Chapter 7: Assessment Methodology provides further details on the 1957/58 consent.

3.4.3. Since then, the surrounding area has seen increasing development from a number of industrial tenants. The former Terra Nitrogen and ICI site, which has now been demolished, is shown located along the northern site boundary of the Proposed Development Site. The access road from Ableton Lane that once led through the centre of the Proposed Development Site into the former Terra Nitrogen and ICI site has been terminated at the southern boundary of the Proposed Development Site, along with the PROW that runs through the field to the south.

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3.4.4. No further changes are evident in the local area until the Seabank 1 & 2 power station located immediately southwest of the Proposed Development Site was constructed in approximately 2000 on the site of the former Seabank Gas Works.

3.4.5. As part of the construction of Seabank 1 (the first module), a number of gas and water service pipelines were installed beneath the Proposed Development Site, and in 2006 five electricity pylons were built within the south-eastern corner of the Proposed Development Site.

3.4.6. A more detailed description of the Proposed Development Site’s history is presented in Table 3-1.

Table 3-1: Historical Map Descriptions of the Proposed Development Site

Published Date

Map Scale

Description

1881 1:2,500 The Proposed Development Site comprises a series of undeveloped fields with field boundaries. An unnamed track is mapped across the centre of the Proposed Development Site from southwest to northeast. A second unnamed track runs southeast to northwest along the north western boundary, and a series of drainage ditches cross-cross the Proposed Development Site.

1957/58 Consent

1965 1:10,560 The Proposed Development Site remains largely unchanged until pre 1965 when a drain is developed through the centre of the site running southeast to northwest (the diversion of the Red Rhine).

A rail track has been developed in the northern section of the Proposed Development Site and continues toward the southeast, extending into the CCR Site (it is labelled as dismantled by 1999 mapping).

1970 1:1,250 The square feature along the southern boundary is labelled as Stowick Cottage. The three rectangular features are no longer present. The track running through the centre of the site is labelled Ableton Lane. The remainder of the site is largely unchanged.

1971 – 1972 and 1972 – 1977

1:2,500 A rectangular embankment feature is shown on the southern boundary of the Proposed Development Site in the eastern section which may be associated with the development of a drainage ditch. The feature is not shown on mapping after 1992.

1975 1: 10,000 The drain developed through the centre of the Proposed Development Site is now labelled Red Rhine.

A drain appears to have been developed in line with the proposed route of the electrical connection.

1992 1:2,500 Stowick Cottage is no longer present. The remainder of the Proposed Development Site is largely unchanged.

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2006 1: 10,000 Five pylons are now present on the Proposed Development Site. The remainder of the site is largely unchanged.

3.5. Area Surrounding the Proposed Development Site

3.5.1. Directly to the north of the Proposed Development Site is the former Terra Nitrogen and ICI site, which was most recently used as a fertiliser manufacturing plant. It ceased to operate in 2008 and the majority of the buildings associated with the former use of the site have been demolished; it is now predominantly a cleared and level site of hardstanding and crushed rubble.

3.5.2. The former Terra Nitrogen and ICI site is currently subject to proposals for a separate CCGT power station by Scottish Power for the ‘Avon Power Station’, which forms part of the cumulative assessment of this report, in terms of the potential for cumulative effects when considered with this Proposed Development and associated infrastructure (see Chapter 7: Assessment Methodology).

3.5.3. The land to the east and northeast of the Proposed Development Site was until recently undeveloped fields. This area is being developed by Severnside Distribution Land Ltd for offices and warehousing (referred to as Central Park in Chapter 7: Assessment Methodology) and is currently being raised to provide flood protection.

3.5.4. A roundabout has recently been constructed immediately to the east of the Proposed Development Site, as part of a new distributor road through Central Park. Severnside Distribution Land Ltd is proposing to link this new roundabout to the A403, by creating a new Spine Access Road which will run along the northern perimeter of the Proposed Development Site (as illustrated in Figure 4-3, Figure 4-4, and Figure 4-9, Volume III of this PEI Report). The Spine Access Road is one of the cumulative developments assessed within this PEI Report, as described in Chapter 7: Assessment Methodology.

3.5.5. Beyond Central Park, approximately 1km east of the Proposed Development Site is the M49 motorway. The Avonmouth LNG Storage Facility and Hallen Industrial Estate are situated to the southeast of the Proposed Development Site, and an area of undeveloped grassland known as Crook’s Marsh is situated immediately south of the Proposed Development Site (west of the Avonmouth LNG Storage Facility).

3.5.6. The existing Seabank 1 & 2 generating station is located immediately southwest of the Proposed Development Site, with the site of the consented SITA waste recycling facility (Local Planning Authority reference PT12/1303/MW, currently under construction) to the northwest of the Proposed Development Site. The

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Severn Estuary is approximately 400m west of the nearest point of the Proposed Development Site.

3.5.7. Seabank Substation is located within the Seabank 1 & 2 compound, approximately 350m south of the Proposed Development Site.

3.6. Other DCO Land

3.6.1. The DCO Application will also include Associated Development for works related to the installation of the proposed cooling water pipeline, the electrical connection to Seabank Substation, and towns and foul water connections, which lie outside of the Proposed Development Site. These works will take place in an area defined as Other DCO Land.

3.6.2. The Other DCO Land is located entirely within the administrative boundary of BCC. The approximate National Grid Reference of the most northerly and southerly parts of the Other DCO Land are 35356, 18281 and 35315, 17947, respectively.

3.6.3. The Other DCO Land covers an area of approximately 19ha and connects the Proposed Development to the electrical and water connection points within the Seabank 1 & 2 generating station site and also covers a proposed cooling water pipeline corridor to the Bristol WWTW.

3.6.4. The part of the Other DCO Land for the electrical connection runs from the northwest corner of the Proposed Development Site southwards within the Seabank 1 & 2 site to the Seabank 400kV Gas Insulated Substation (GIS), and is approximately 440m in length and 100m wide. An additional utilities corridor has been included within the DCO Site to incorporate foul water and mains water connections to the Site and includes the northernmost 100m within the Seabank 1 & 2 station, between Severn Road and the Proposed Development Site (as illustrated in Figure 3-1, Volume III of this PEI Report). These parts of the DCO Site are hardstanding and concrete.

3.6.5. The Other DCO Land for the proposed cooling water pipeline corridor runs from the western most point of the Proposed Development Site, around the perimeter of Seabank 1 & 2, in a southward direction to the Bristol WWTW and is approximately 4.5km in length and generally 30m wide.

3.6.6. Due to the length of the proposed cooling water pipeline corridor, the Other DCO Land has been split into three figures: Figures 3-4a, 3-4b, and 3-4c (Volume III of this PEI Report) provide an aerial image of the Other DCO Land. They also show other notable features in the vicinity, including the photograph locations for the photographs presented in Plates 3-7 to 3-15.

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Plate 3-7: Photograph 7 showing the connection between the Proposed Development Site and Seabank 1 & 2 [Date Taken 20 February 2013]

Plate 3-8: Photograph 8 showing the entrance of Seabank 1 & 2 Site [Date Taken 20 February 2013]

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Plate 3-9: Photograph 9 of Seabank 400kV Substation [Date Taken 20 February 2013]

Plate 3-10: Photograph 10 showing corner of Chittening Road and Severn Road [Date Taken 11 November 2013]

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Plate 3-11: Photograph 11 showing the corner of Smoke Lane and Chittening Road [Date Taken 04 September 2013]

Plate 3-12: Photograph 12 showing footpath facing west running adjacent to the railway [Date Taken 04 September 2013]

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Plate 3-13: Photograph 13 showing culvert facing south [Date Taken 04 September 2013]

Plate 3-14: Photograph 14 – Facing north across Popular Way East [Date Taken 04 September 2013]

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Plate 3-15: Photograph 15 – Facing north from the Bristol WWTW Entrance [Date Taken 04 September 2013]

3.6.7. The proposed cooling water pipeline corridor extends from the most westerly point of the Proposed Development Site, around the perimeter (but within) the Seabank 1 & 2 site and then south towards the Seabank Substation (Photograph 8), before turning south to Chittening Road.

3.6.8. The proposed cooling water pipeline corridor follows the route of an internal access road within Seabank 1 & 2, after which it follows a footpath past the Seabank Substation towards Chittening Road.

3.6.9. The proposed cooling water pipeline corridor runs south alongside Chittening Road and includes the grass verges, with the Viridor Resource Recovery Centre and Sevalco W4B sites to the east (Photograph 9). This part of the Other DCO Land is situated on the west side of Chittening Road for the first 100m, before crossing it to the opposite side of the road and continuing south to Chittening Industrial Estate (Photograph 10 & 11). It therefore includes the grass verges either side of Chittening Road, and crosses this road in one location.

3.6.10. Figure 3-4b (Volume III) illustrates the part of the proposed cooling water pipeline corridor in the vicinity of the operational railway line. The proposed cooling water

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pipeline corridor continues south, passing the firefighting training station and includes an existing tarmacked footpath and grass field up to the railway.

3.6.11. The proposed cooling water pipeline corridor crosses under the railway line at grid reference 353087,180906 and turns in a easterly direction adjacent to the railway on grassland for approximately 200m towards an existing distribution centre operated by Honda, as shown on Figure 3-4b (Volume III of this PEI Report). This part of the proposed cooling water pipeline corridor is partly tarmacked and follows the route of an existing footpath that runs adjacent to the railway, with grass verge alongside (Photograph 12).

3.6.12. Figure 3-4c (Volume III) shows the part of the proposed cooling water pipeline corridor between the footpath adjacent to the southern side of the railway and the WWTW. It predominantly follows the existing PROW, which are hard surfaced, or on grass verges alongside the PROW.

3.6.13. Photograph 13 illustrates a culvert, facing south with the existing 300mm and 550mm water pipelines exposed, which the proposed cooling water pipeline corridor crosses.

3.6.14. It then crosses Lawrence Weston Road (Photograph 14), and reaches the Bristol WWTW via a grassed verge, as shown in Photograph 15.

3.6.15. A detailed description of the land use and habitats of the Other DCO Land is presented in Chapter 16: Ecology.

3.6.16. A description of the site history of the Other DCO Land and the surrounding area is presented in Chapter 13: Ground Conditions.

3.7. Sensitive Receptors in the Vicinity of the Proposed Development Site and Other DCO Land

3.7.1. When undertaking an EIA it is important to understand which receptors will be considered as part of the assessment. Key receptors for each topic area have been identified as part of the assessment process and details are included in the relevant chapters. Where distances are quoted here and in following chapters the distance is defined (unless otherwise stated) as the closest point from the site boundary to the location being described).

3.7.2. The area surrounding the Proposed Development to the south and north is occupied by various industrial uses, both large and small, whilst the land to the east and northeast of the Proposed Development Site currently remains undeveloped open fields, although this area is subject to a separate development by Severnside Distribution Land Ltd.

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Nearest Residential Properties

3.7.3. The nearest residential properties to the Proposed Development Site are located approximately 1.5km north of the Proposed Development Site in Severn Beach, and a number of small number of farms located approximately 1.1km southeast.

3.7.4. Other small residential settlements in the vicinity of the Proposed Development Site including Pilning, Hallen, and Easter Compton, approximately 1.5km north, 2km south east, and 2.2km northeast respectively.

3.7.5. The larger communities of Avonmouth and Bristol are located some 5km southwest and 10km east of the Proposed Development Site respectively.

3.7.6. The nearest residential properties to the Other DCO Land are situated approximately 800m east of the proposed cooling water pipeline corridor at its most southern point (near the WWTW). There are no residential properties closer than 800m between the WWTW and Seabank 1 & 2, as shown in Figure 3-5 (Volume III of this PEI Report).

Nature Conservation

3.7.7. A number of conservation designations exist within 2km of the Proposed Development Site of both European and national significance, in particular the Severn Estuary.

3.7.8. The Severn Estuary is located approximately 400m to the west of the Proposed Development Site and is an internationally designated Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar Site and Site of Special Scientific Interest (SSSI) due to both habitat and species assemblages.

3.7.9. The SAC designation is a response to the rich marine and terrestrial habitat and species found within the Severn Estuary and includes the following features:

• Estuaries;

• Tidal rivers;

• Mud flats;

• Sand flats;

• Lagoons (including saltwork basins);

• Salt marshes;

• Salt pastures;

• Salt steppes;

• Reefs;

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• Migratory fish (river and sea lamprey and twaite shad) [see Figure 3-5, Volume III of this PEI Report]; and

• Species of bird/waterfowl/fish.

3.7.10. Further details of the above features are described in Chapter 16: Ecology. It should be noted however that not all of the features for which the Severn Estuary SAC is designated are to be found within close proximity to the Proposed Development Site itself.

Biodiversity Action Plan (BAP) Habitat

3.7.11. The majority of the Proposed Development Site comprises marshy grassland and there are a limited number of areas of scrub and hedgerow, which are designated as a ‘broad habitat’ under the UK Biodiversity Action Plan (UK BAP). The Proposed Development Site is also immediately adjacent to an area designated as Coastal and Floodplain Grazing Marsh, which is a BAP priority habitat, identified as “being the most threatened and requiring conservation action”.

3.7.12. Interconnecting rhines (drainage ditches) on the Proposed Development Site and immediately adjacent have been identified by the Local Wildlife Trust as Sites of Nature Conservation Interest (SNCI). The Red Rhine is the largest drainage channel within the area and running through the Proposed Development Site in an east to west direction.

3.7.13. It should be noted that the proposed water cooling pipeline corridor crosses local rhines, which are designated as SNCI.

Flood Risk

3.7.14. The River Severn is the closest principal watercourse and is located approximately 400m west of the Proposed Development Site. The Proposed Development Site lies entirely within Flood Zone 3a as classified by the EA, and is therefore at risk from coastal flooding in a 1 in 200 year event or from fluvial flooding during a 1 in 100 year event.

Historic Environment

3.7.15. The wider landscape encompassing the DCO Site consists of a combination of open rural landscape, heavy industry, villages, towns and the estuary. The landscape around the DCO Site has been strongly influenced by its past and present industrial land uses.

3.7.16. Three scheduled monuments have been identified within 5km of the Proposed Development Site, and are noted in Chapter 15: Archaeology and Cultural Heritage.

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3.7.17. Fifteen Grade II and fourteen Grade I listed buildings exist within 5km of the Proposed Development Site, whilst thirteen of the Grade II listed buildings are located within 2km. Underground archaeology may be present onsite or in the vicinity of the Proposed Development Site, which is discussed in Chapter 15: Archaeology and Cultural Heritage.

Other Receptors

3.7.18. Other potential sensitive receptors have been identified within 2km of the Proposed Development Site based on a review of available maps, aerial photographs, initial studies, site visits and consultations:

• Fourteen non statutory designated sites for nature conservation within 1km of the Proposed Development Site. All of which are designated as SNCI and two which area also designated as Avon Wildlife Trust Sites (AWTS);

• Ecological receptors (bats and breeding birds);

• Traffic and transport receptors;

• Local PROW (as located in Figure 3-5, Volume III of this PEI Report); and

• Key short, medium and long-distance views into the Proposed Development Site.

3.7.19. Figure 3-5 (Volume III) illustrates the main constraints and environmental receptors within the surrounding area.

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PEI Report – Chapter 4 Project Description

4. Project Description

4.1. Introduction

4.1.1. This chapter of the PEI Report describes the Proposed Development and its associated infrastructure, and is used in subsequent technical chapters to assess the potential effect on the environment and socio-economic conditions.

4.1.2. Chapter 5: Enabling Works and Construction presents a description of the key activities and processes that will be carried out during the enabling works and construction of the Proposed Development.

4.2. Overview

4.2.1. The Applicant is seeking a DCO for the development of a generating station fuelled on natural gas generating up to 1,400MWe net electrical capacity. The generating station will comprise up to two CCGT units with a total capacity of up to 1,400MWe, and gas-fired peaking plant totalling up to 240MWe net electrical capacity. The electrical capacity of the CCGTs will be reduced if the peaking plant is built to ensure the total output capacity of the Proposed Development does not exceed 1,400MW.

4.2.2. This combination of CCGT units and peaking plant is required to be able to effectively respond to national need to meet electricity demand, as discussed in Chapter 6: Project Need and Alternatives of this PEI Report. CCGTs are recognised to be a highly efficient way to generate electricity, while peaking plant can be operated for short durations and started at short notice to rapidly meet fluctuating electrical demand.

4.2.3. The CCGT units consist of a gas turbine, a Heat Recovery Steam Generator (HRSG), a steam turbine, and an electrical generator. Electricity is generated both by the gas turbine and the steam turbine, with the exhaust gases from the gas turbine generating steam through the HRSG to power the steam turbine.

4.2.4. The capacity of the CCGT units will be determined by the specific technology selected through a procurement exercise at the time of construction of the Proposed Development. The inclusion and capacity of the peaking plant is therefore optional and dependent on the output capacity of the CCGT units, as the net electrical capacity of the Proposed Development will not exceed 1,400MWe.

4.2.5. Supporting infrastructure such as cooling water system, water treatment plant and other services are required on the Proposed Development Site, and these are described in more detail later in this chapter.

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4.2.6. The Proposed Development also requires the installation of a new water pipeline to supply water for the cooling water system from Bristol WWTW, towns and foul water connections, and an electrical connection to Seabank Substation. These are considered to be Associated Development and are described further below.

4.2.7. In accordance with the requirements of the National Policy Statement for Fossil Fuel Electricity Generating Infrastructure (NPS EN-2) (Ref. 4-1), the plant is being designed to be both Carbon Capture Ready and Combined Heat and Power (CHP) Ready.

4.2.8. There are some aspects of the Proposed Development design that have yet to be fixed. It will not be possible to fix these elements in advance of a contract being awarded for the detailed design and construction of the Proposed Development. For example, the precise location and scale of the buildings within the Proposed Development may vary depending upon the contractor appointed and their specific selection and configuration of the plant and process equipment. The design of the Proposed Development therefore needs to incorporate a degree of flexibility to allow for such circumstances.

4.2.9. The elements of the Proposed Development where flexibility is required are described in detail below. In order to ensure a robust assessment of the likely significant environmental effects of the Proposed Development, the EIA will be undertaken adopting the principles of the ‘Rochdale Envelope’, as advocated in the Planning Inspectorate’s Advice Note 9 (Ref. 4-2). This will involve assessing the maximum and minimum parameters for the elements where flexibility needs to be retained. Where this approach is applied to the specific aspects of the EIA this has been confirmed within the relevant chapters of this PEI Report and will also be confirmed within the ES, which will report on the complete findings of the EIA and form part of the Application for Development Consent.

4.2.10. Further detail is provided in the following sections.

4.3. Description of the Proposed Development

4.3.1. The NSIP, referred to as the Proposed Development in this PEI Report, has been broken down into land parcels as shown in Figure 4-1a (Volume III of this PEI Report). Figure 4.1b shows the proposed cooling water pipeline corridor that will be constructed as Associated Development to the Proposed Development.

4.3.2. The Proposed Development comprises the following main components:

• Up to two CCGT units, comprising up to two gas turbines, up to two steam turbines, and up to three electricity generators within turbine building(s);

• Up to two HRSG within heat recovery steam generator building(s);

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• Up to two emissions stacks associated with the CCGT units and associated emissions monitoring systems;

• Cooling for the Proposed Development is to be provided by a hybrid cooling water system, supplied with water from Bristol WWTW. The water will be delivered to the Proposed Development Site through a new underground water pipeline which will supply Seabank 1 & 2 as well as the Proposed Development;

• A grid connection to the UK transmission network via an existing sub-station;

• A peaking plant facility fuelled by natural gas and with black start capability on distillate fuel oil, with a net electrical output capacity of up to 240MWe.

4.3.3. In addition, the main plant is supported by additional infrastructure including up to three generator transformers, a water treatment plant, pumps and storage tanks, gas reception facility, and administration and control buildings.

4.3.4. As required by the EU Directive on Geological Storage of Carbon Dioxide (Ref. 4-3) and DECC Guidance on Carbon Capture Readiness (Ref. 4-4), an area has been allocated for potential future use for the retrofitting of carbon capture and compression equipment, should it be required to be installed in the future. This area will be used for temporary contractor’s laydown and facilities during the construction of the Proposed Development.


4.3.5. The Proposed Development has been designed to operate independently of the existing Seabank 1 & 2 generating station, however there will be a number of shared services including access roads, cooling water treatment and supply, gas supply and grid connection, and foul water and towns water connections.

4.3.6. The CCGTs will be natural gas fired, with the fuel sourced from the National Grid Gas Transmission Network. The existing Seabank 1 & 2 station is currently supplied by two high pressure natural gas feeds (the Abson pipeline and Feeder 14) that enter the southeast corner of the Proposed Development Site (the Site) and extend through the Proposed Development Site to Seabank 1 & 2. The Abson pipeline will need to be diverted within the Site boundary (parallel to the Feeder 14 pipeline which runs along the southern boundary of the Site) and will be used to supply the gas the Proposed Development via an off-take within the Site. This is discussed in Chapter 5: Enabling Works and Construction.

4.3.7. The use of natural gas means that emissions of sulphur dioxide (SO2) and particulates from the Proposed Development will be negligible. Emissions of

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nitrogen oxides (NOx) will be controlled by primary means and the use of dry low NOx burners operated and controlled through an automated process control system in accordance with Best Available Techniques (BAT). In this way, emissions will be controlled to meet the requirements of the Industrial Emissions Directive (IED) (Ref. 4-5); secondary abatement of emissions to air is not proposed or considered necessary.

4.3.8. The CCGTs and peaking plant will be located in the western half of the Proposed Development Site, within an area defined as the Generating Station Site, which is adjacent to the existing Seabank 1 & 2, as shown in Figure 3-1, Volume III of this PEI Report. This corresponds with development parcels 1, 2 and 3 in Figure 4-1a (Volume III). The eastern area is the area to be retained so that the Proposed Development is Carbon Capture Ready (CCR).

4.3.9. The main structures that form the Proposed Development will comprise:

• One or two turbine buildings with a maximum height of up to 33m above the maximum finished ground level (up to 41.5m AOD following land raising of the ground to a maximum 8.5m AOD, as discussed in Chapter 5: Enabling Works and Construction), along with up to two 90m high exhaust stacks (up to 98.5m AOD);

• One or two HRSG buildings with a maximum height of up to 45m (up to 53.5m AOD);

• Up to two banks of 24 hybrid cooling water systems, each with a maximum diameter of 17.5m and a height of up to 19m (up to 27.5m AOD); and

• The peaking plant, which will have a maximum height of up to 24m (32.5m AOD), along with two exhaust stack 45m in height (up to 53.5m AOD).

4.3.10. There will also be additional ancillary structures onsite of lower height and a smaller footprint than these main buildings to accommodate for example, workshops and offices, which are illustrated in Figures 4-2 to 4-6 (Volume III of the PEI Report) and listed in Tables 4-1 and 4-2.

4.3.11. As the final technology selection has not been made, there are two potential plant configurations that could be utilised for the Proposed Development: single-shaft and multi-shaft. Although they result in the same electrical output, they do result in a slightly different mode of operation and appearance. It is proposed that the ‘Rochdale Envelope’ approach is used to retain the flexibility to build either plant configuration, as discussed in Chapter 2: The DCO and EIA Process. Both configurations have therefore been assessed in this PEI Report and will be

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retained in the assessments presented in the final ES to be submitted with the DCO Application. Whichever configuration gives rise to that worst-case predicted effect has been assessed in the individual technical chapters.

4.3.12. As outlined in the previous paragraph, the key environmental difference between the two configurations is their visual appearance, as a number of buildings are combined for the multi-shaft arrangement and there are differing numbers of generators and transformers, resulting in a slightly smaller footprint for the multi-shat configuration. This is discussed further later in this section.

4.3.13. The Proposed Development will have a design life of 30 years, which may be extended depending on the number of running hours and condition of the plant. The technical assessments have been based on this design life.

4.3.14. The plant will have the ability to operate twenty-four hours per day, seven days per week, if required, although with periodic offline periods for maintenance.

4.3.15. The actual hours of operation of the CCGTs or the peaking plant will be subject to the national demand for electricity and the economic viability of gas-fired generation. It is anticipated that the CCGTs will operate at an average 31% load factor (an average 2,716 hours per year) over the course of its lifetime, with the peaking plant expected to run for short periods of time during high demand. For the purposes of the assessments undertaken in this PEI Report however, it has been conservatively assumed that the CCGTs could operate for up 7,884 hours a hour (90% availability) and the peaking plant up to a maximum 1,500 hours a year (approximately 17% availability).

4.3.16. As discussed above, an area has been reserved for the potential future siting of carbon capture and compression equipment, should it be required at a future date, in order to meet the requirements set out in the EU CCS Directive for Geological Storage of Carbon Dioxide and to demonstrate that the Proposed Development is CCR. The actual design and consenting of CCS technology and infrastructure does not form part of this DCO Application, as it is not currently required to be installed at the Site. Any CCS infrastructure would need to be consented separately at the time it is required in the future. However, in accordance with DECC CCR Guidance requirements, the CCR Site is included within the Proposed Development Site boundary. It is also proposed that this area is utilised for construction and laydown activities, as discussed in Chapter 5: Enabling Works and Construction.

4.3.17. Opportunities for the provision of low-grade steam or waste heat to local third parties are being explored. If feasible this will enable the plant to operate as a CHP plant, which would maximise the use of available heat from the fuel and increase the overall plant thermal efficiency. The feasibility of CHP has been further explored in the CHP-Ready report that has been prepared to accompany

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the DCO Application. This is presented in Appendix N, Volume II of this PEI Report.

Finished Ground Levels

4.3.18. It is expected that the Generating Station Site will need to be raised from current levels in order to manage potential flood risk, as discussed in Chapter 14: Flood Risk, Hydrology and Water Resources.

4.3.19. Hydraulic modelling undertaken to inform the Flood Risk Assessment indicates that the finished floor levels within the Generating Station Site will need to be raised to a minimum of 8.31m AOD to protect from extreme tidal flooding events. The DCO Application therefore includes for the ability raise this part of the Proposed Development Site by up to an average 2.2m to 8.5m AOD, as illustrated in Figure 5-1, Volume III of this PEI Report.

4.3.20. This represents a maximum ground level and incorporates more than the suggested degree of contingency by the Environment Agency. This is to avoid committing to an overly precise figure that a Contractor may be unable to deliver. It is expected that the finished site levels will be less than this to allow the construction Contractor to lay a gravel or concrete platform for construction. Certain infrastructures such as the cooling water system, which are inherently bunded and therefore protected from flooding, could also be constructed at current site levels or lower than this maximum ground height.

4.3.21. Land raising will not be undertaken on the CCR Site or the Utilities, Services and Landscaping Area within the Proposed Development Site. The ‘Other DCO Land’, within which the electrical connection and water pipeline is being constructed (and which lies within BCC’s administrative boundary), will also be retained at current site levels.

4.3.22. It is estimated that up to 158,000m3 of material may be required for land raising, based on the predicted maximum extent of land raising defined above. For the purpose of assessing the effect of road traffic movements, it has been assumed that this material will be imported to Site by HGV over the course of 6 months. The effect of these HGV movements on the road network is discussed in Chapter 10: Traffic and Transport.

Layout Configurations

4.3.23. As discussed above, at this stage in the development of the plant design, it is not possible to define which plant configuration will be required and therefore both options are retained within the DCO Application and assessed within the EIA process.

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4.3.24. A single-shaft configuration consists of only one gas turbine, steam turbine, generator and HRSG per CCGT unit, with the gas turbine and steam turbine coupled to the generator.

4.3.25. The multi-shaft configuration also includes two gas turbines and generators (the same number as two single-shaft units), but supplies steam from the HRSG to a separate steam turbine and generator that is common to each train.

4.3.26. Plate 4-1 presents a schematic diagram to illustrate the differences between these arrangements. The single-shaft arrangement illustrated in Plate 4-1 only includes one CCGT unit. The Proposed Development may therefore contain twice the arrangement shown below should two single-shaft arrangements be built.

Plate 4-1: Single and Multi-shaft Arrangements

* The single-shaft arrangement illustrates one unit only. The Proposed Development will have up to two single-shaft.

4.3.27. Figures 4-2 and Figure 4-3 (Volume III of this PEI Report) illustrate the indicative layouts (based on maximum parameters) for the single-shaft and multi-shaft configurations. The building footprint for the multi-shaft configuration is shown to be slightly less than the single-shaft configuration, and the massing of the turbine and HRSG buildings orientated slightly differently, as described below. Regardless of which design is selected it would be within the development parcels illustrated in Figure 4-1a (Volume III of this PEI Report).

Height and Massing

4.3.28. In accordance with the principles of the Rochdale Envelope, as set out in the Planning Inspectorate Guidance Note 9, the DCO Application defines the maximum and minimum parameters for the Proposed Structures such that the envelope can be defined and adequately assessed.

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4.3.29. In brief, the maximum parameters comprise two CCGT units, two banks of cooling water systems (containing a total 24 cooling water system), and a peaking plant facility plus Associated Development.

4.3.30. The indicative layouts and illustrations show the maximum and minimum footprints and heights of the buildings and structures, as well as the general massing of the Proposed Development. Figure 4-1a (Volume III of this PEI Report) illustrates that there is some flexibility on where individual buildings can be located within a development parcel.

4.3.31. The technical assessments have taken into account the Rochdale Envelope and, where applicable, assessed the worst case parameters for each parameter. To facilitate the stack height determination and undertake the air quality impact assessment however it was necessary to model the stacks and buildings in a specific location, as shown in the layout drawings below. Chapter 11: Air Quality includes a discussion on sensitivity analysis, since small changes in the stack location may be expected at the detailed design stage, however without changing the general massing of the Proposed Development or position of the stacks in relation to the main buildings onsite.

Maximum Parameters

4.3.32. Figures 4-2 and 4-3 (Volume III of this PEI Report) provide an indicative 2-dimensional layout of the Proposed Development based on the maximum building footprints, for the single-shaft and multi-shaft configurations, respectively.

4.3.33. Figures 4-4 and 4-5 (Volume III) illustrates selected cross-sectional drawings showing the maximum building and structure heights for the two configurations.

4.3.34. Irrespective of plant configuration, the tallest structures onsite will be the stacks associated with the CCGT units, which will be 90m high (up to 98.5m AOD, assuming that the finished ground levels are raised to a maximum height of 8.5m AOD as discussed above). The peaking plant stacks will be 45m (up to 53.5m AOD).

4.3.35. The tallest buildings will be the HRSG buildings, which are up to 45m above the finished ground level (up to 53.5m AOD).

4.3.36. The turbine buildings are proposed to be located immediately northwest of the HRSG buildings and will be up to 33m (up to 41.5m AOD) for a single-shaft configuration and up to 35m (up to 43.5m AOD) for a multi-shaft configuration. Further to the northwest, the cooling water systems will be slightly lower, up to 19m in height (up to 27.5m AOD).

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4.3.37. West of the HRSG and turbine buildings, near the southern boundary of the Proposed Development Site, the cooling water backup tank and towns water tank will be up to 28m in height (up to 36.5m AOD).

4.3.38. The structures east of the HRSG buildings are generally lower rise, with the ancillary buildings between 2m and 17m (10.5m AOD to 25.5m AOD). The peaking plant building though is up to 24m (up to 32.5m AOD).

4.3.39. The main massing of the Proposed Development is therefore situated in the centre of the Generating Station Site, with the HRSG buildings and stacks being the most prominent features, along with the peaking plant stacks to the east.

4.3.40. The maximum parameters also include structures to penetrate the ground level to the water table. This is expected to include foundations for the turbine building, HRSG buildings, and cooling water pits.

4.3.41. Figure 4-6 (Volume III of this PEI Report) provide indicative 3D illustrations of the Proposed Development from selected viewpoints, based on the maximum building footprints and heights.

Minimum Parameters

4.3.42. The ‘Rochdale Envelope’ allows a range of parameters to be applied for. A minimum height and footprint for the proposed structures and buildings is therefore discussed in this subsection. The Applicant is not committed to building all the structures and buildings listed in the DCO Application however and has the flexibility to phase the Proposed Development or decide to omit certain features. For example, minimum parameters are provided for the peaking plant, although these are effectively an option, depending on the final choice of CCGT plant, and therefore might never be built.

4.3.43. The stack associated with the CCGT and peaking plant will be 90m high and 45m high respectively (up to 98.5m AOD and 53.5m AOD); no range of parameters is being sought for the stacks to provide certainty of their height and the maximum air quality effects associated with these emission sources.

4.3.44. For the other structures onsite, a height AOD has not been stated since the ground level may not need to be raised to the full 8.5m AOD to satisfy the EA requirements for flood protection.

4.3.45. The HRSG building will be a minimum of 35m above the finished ground level and a minimum footprint of 37m by 25m.

4.3.46. The turbine building is located immediately adjacent to the HRSG building and will be a minimum of 27m above the finished ground level. The turbine auxillary

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building will be a minimum 14m high. These buildings have the greatest physical footprint onsite and are both a minimum of 60m by 33m.

4.3.47. Further to the northwest, the cooling water system will be slightly lower, a minimum of 15m above the finished ground level.

4.3.48. West of the HRSG and turbine buildings, near the southern boundary of the Proposed Development Site on the indicative layout plans, the cooling water backup tank and towns water tank will be a minimum of 16m above the finished ground level.

4.3.49. The structures east of the HRSG buildings are generally low rise, with the ancillary buildings a minimum of approximately 16m above the finished ground level. The peaking plant facility will have a minimum height of 14m.

4.3.50. The main massing of the Proposed Development is therefore situated in the west of the Generating Station Site, with the HRSG buildings and stacks being the most prominent features.

4.3.51. Table 4-1 and 4-2 provide a list of the main structures associated with the Proposed Development and their maximum and minimum parameters for both the single-shaft and multi-shaft configurations, respectively.

Table 4-1: Proposed Development Parameters for the Single-shaft Configuration

Structure Number of units

Maximum Minimum

Height (m)

Length (m)

Width (m)

Height (m)

Length (m)

Width (m)

Turbine Building 2 33 70 37 27 60 33

Turbine Auxiliary Building 2 17 70 37 14 60 33

HRSG Building 2 45 45 30 35 37 25

CCGT Stack 2 90 d8.5 90 d8.5

Peaking Plant building 1 24 77 58 14 59 24

Peaking Plant Stack 2 45 d7 45 d4

Gatehouse 1 4 17 11 3 10 5

Gas Receiving Station 1 2 108 20 2 108 20

Gas Conditioning Compound 1 4 53 18 4 40 14

Hybrid Cooling System 2 19 100 35 15 80 30

Fire Water Tank 1 15 d12 7 d6

Fire Fighting Building 1 5 8 8 4 6 6

Water Treatment Building 1 10 33 14 5 22 8

Demin Water Storage Tank 1 9 d9 6.5 d5

BFW Pump house 2 17 25 24 15 20 18

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Maximum Minimum

Height (m)

Length (m)

Width (m)

Height (m)

Length (m)

Width (m)

Chemical Sampling Dosing 2 16.5 25 24 14 20 18

HRSG Auxiliary Building 2 17 25 24 15 20 18

Emergency Diesel Generators 2 3 11 8 3 5 4

Workshop Stores 1 15 36 26 6 26 19

Plant Laydown 1 N/A 34 12 N/A 34 12

Admin Control Building 1 15 48 19 8 24 15

Car Park 1 N/A 50 5 N/A 50 5

GIS and Control Room 1 15 38 14 15 22 14

Distillate Oil Tank 2 12.5 d10 10 d8

Cooling Water Dosing Building 1 4.5 20 10 4.5 15 10

Cooling Water and Towns Water Back Up Tank 2 28 d25 16 d14

Cooling Water Switchgear Building 1 5.6 31 12 3.5 25 8

Transformer compound 2 12 35 24 10 25 20 d=diameter

Table 4-2: Proposed Development Parameters for the Multi-shaft Configuration


Maximum Minimum

Height (m)

Length (m)

Width (m)

Height (m)

Length (m)

Width (m)

Turbine Building 1 35 132 60 28 120 58

HRSG Building 2 45 45 30 35 37 25

CCGT Stack 2 90 d8.5 90 d8.5

Peaking Plant building 1 24 77 58 14 59 24

Peaking Plant Stack 2 45 d7 45 d7

Gatehouse 1 4 17 11 3 10 5

Gas Receiving Station 1 2 108 20 2 108 20

Gas Conditioning Compound 1 4 53 18 2 40 14

Hybrid Cooling System 24 19 100 35 15 80 30

Fire Water Tank 1 15 d12 7 d6

Fire Fighting Building 1 5 8 8 4 6 6

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Maximum Minimum

Height (m)

Length (m)

Width (m)

Height (m)

Length (m)

Width (m)

Water Treatment Building 1 10 33 14 5 22 8

Water Storage Tank 1 9 d9 6.5 d5

Pump house 2 17 25 24 15 20 18

Chemical Sampling Dosing 1 16.5 25 24 14 20 18

HRSG Auxiliary Building 2 17 25 24 15 20 18

Emergency Diesel Generators 1 3 11 8 3 5 4

Workshop Stores 1 15 36 26 6 26 19

Plant Laydown 1 N/A 34 12 N/A 34 12

Admin Control Building 1 15 49 19 8 24 15

Car Park 1 N/A 50 5 N/A 50 5

GIS and Control Room 1 15 38 14 15 22 14

Distillate Oil Tank 2 12.5 d10 10 d8

Cooling Water Dosing Building 1 4.5 20 10 4.5 15 10

Cooling Water Back Up Tank 2 28 d25 16 d14

Cooling Water Switchgear Building 1 5.6 31 12 3.5 25 8

Transformer compound 3 12 35 24 10 25 20

d=diameter

The Main CCGT Generating Station (Development Parcel 1)

4.3.52. The CCGT operates by combusting natural gas to produce hot gases, which in turn drive a gas turbine. In the gas turbine, gas will be mixed and combusted with compressed air and the hot combustion gases will expand, rotating the turbine blades at high speed. This will drive the generators to produce electricity for export to the national transmission system.

4.3.53. A substantial amount of heat remains in the gas turbine exhaust, which is passed into a HRSG (a type of boiler) to use the heat to produce steam. This in turn is used to drive a steam turbine either connected to the same generator or a separate steam turbine generating module, thereby maximising electricity generation from the fuel being combusted. The exhaust steam from the steam

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turbine is condensed back into water which is returned to the HRSG to continue the process. The waste gases from the HRSG boiler will be released into the atmosphere via an exhaust stack, which will be 90m high (up to 98.5m AOD).

4.3.54. The main difference between open cycle and combined cycle gas turbines (OCGTs and CCGTs respectively) is that CCGT plants use residual heat from the gas turbine exhaust stack to generate steam used in the energy conversion process.

4.3.55. The electrical efficiency of a modern CCGT power station such as this Proposed Development is in the range of about 55-60%, which is considerably higher than that for an OCGT or a conventional coal, oil or gas fired steam turbine generating plant. The Proposed Development is expected to achieve 58% efficiency.

Supplementary Firing

4.3.56. Supplementary firing is a method of producing additional steam to generate additional electricity for short periods by firing a dedicated gas burner located between the gas turbine and the HRSG. Supplementary firing would increase the power output of the CCGT plant by around 0.4%. It does however reduce the efficiency slightly.

4.3.57. At this stage, it is not known if supplementary firing would be designed into the plant, although it is fitted as standard on some CCGT units. It has therefore been included within the Rochdale Envelope assessed for the Proposed Development. It leads to only a marginal increase in the footprint of the HRSG and turbine buildings (of the order of 5m additional length), which has therefore been included in the maximum parameters listed in Table 4-1. It has also been considered prudent to base the assessments on the slightly lower plant efficiency that would result from the inclusion of supplementary firing.

Fuel Type and Source

4.3.58. The fuel source for the turbines will be natural gas, supplied from the UK National Grid Transmission network and in accordance with the gas specification of that network.

4.3.59. The current Seabank 1 & 2 generating station is supplied from two high pressure natural gas feeds from the southeast corner of the Proposed Development. These existing supply pipelines will be used to supply the gas to the Proposed Development Site, though will need to be slightly diverted within Proposed Development Site to accommodate the new plant and a connection taken from it, as discussed in Chapter 5: Enabling Works and Construction.

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Gas Receiving Station

4.3.60. A gas receiving station is required to receive the natural gas fuel from an off take from the Abson pipeline (see Chapter 3: The Site and Its Surroundings), and to depressurise it in advance of using it as fuel in the Proposed development. A pigging facility would be included, which allows a ‘Pipeline Inspection Gauge’ (PIG) to be passed along the pipeline for periodic cleaning and maintenance checks.

4.3.61. The gas receiving station is indicated as being east of the peaking plant facility on the indicative layouts; however it could be located anywhere within the area labelled as Development Parcel 1 or 3 in Figure 4-1a. It would have a maximum height of 2m (10.5m AOD) and a footprint of up to 108m by 20m.

Gas Conditioning Compound

4.3.62. A gas conditioning compound is required to heat, hydrate/dehydrate and filter the gas before it is used as fuel. It would typically be expected to include fuel gas filters, fuel gas heaters, orifice metering skid and gas chromatograph to measure the quality of the incoming gas. In addition it will include the various pipework headers to feed the two CCGT units. All of this equipment will be enclosed within a secure fenced off area, as shown on the indicative layouts.

4.3.63. The compound will be up to 4m height (12.5m AOD) and shall have a footprint of up to 53m by 18m.

Stacks

4.3.64. Combustion gases will be emitted to the atmosphere via two standalone stacks, located adjacent to the HRSG Building within the Generating Station Site. Based on dispersion modelling and an assessment of the potential impacts, the stacks will be 90m (up to 98.5m AOD). This is discussed in more detail in Chapter 11: Air Quality.

4.3.65. The primary release of emissions from the Proposed Development will be the exhaust gases produced from combustion of natural gas in the gas turbine, which will be regulated by the Environment Agency under the Environmental Permit required for the operation of the plant. The key components of the exhaust gases will be water vapour and carbon dioxide (CO2), with traces of oxides of nitrogen (NOx) and carbon monoxide (CO).

4.3.66. Emissions to air from the combustion process will be compliant with emission limits set within the EU Industrial Emissions Directive (IED) (Ref. 4-5), transposed into UK law by the Environmental Permitting Regulations (Ref. 4-6). The design and operation of the Proposed Development will minimise pollutant emissions including NOx through automated control of the combustion conditions.

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4.3.67. Flue gases discharged from the stacks will be monitored by an on-line continuous emissions monitoring system (CEMS), comprising a sampling system, analyser unit and data logger. The gas components measured will be, as a minimum, those stipulated by current legislation. Other gas components may be monitored for the purposes of process control. The components monitored are likely to include:

• NOX concentration;

• CO concentration;

• Oxygen concentration;

• Moisture content;

• Temperature; and

• Gas flow rate.

4.3.68. All of the parameters to be monitored will be documented in the Environmental Permit, and monitoring data will be submitted to the EA to demonstrate continued compliance.

4.3.69. A low intensity multi visual aviation light will be added to the CCGT stacks for use during night time, and colour contrasting visual markers for daylight hours to assist local aviation users.

Emergency Diesel Generators

4.3.70. Up to two emergency diesel generators approximately 1.5MW capacity will be located adjacent to the gas conditioning compound and workshops towards the south of the Proposed Development Site, within the Generating Station Site, for backup power to the onsite administrative buildings should the peaking plant not be built. The capacity of these generators is expected to be relatively small and will only be required as backup during a power failure onsite.

4.3.71. The generators will be supplied by fuel from the bulk distillate storage tanks located in proximity to the generators.

Gatehouse; Workshop, Store and Control Building’s

4.3.72. The gatehouse and main Site access will be located on the northern perimeter of the Proposed Development Site, near the eastern end of the Generating Station Site, with direct access from/to the Spine Access Road (currently under construction).

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4.3.73. The control building, workshop and stores are within the Generation Station Site south of the gatehouse. The existing 11kV line will be used to provide electricity to these structures.

Storage Tanks

4.3.74. A cooling water storage tank and towns water tank are required to provide cooling water supply. The tanks will be up to 25m diameter and up to 28m height (36.5m AOD) and would have the ability to maintain the CCGT units for a few hours in the temporary disruption of a water supply from the Bristol WWTW.

Waste Water Treatment Plant

4.3.75. The waste water treatment plant is indicatively located adjacent to the water storage tanks along the southern boundary of the Proposed Development Site and will be up to 6m in height (14.5m AOD). It is required to treat process water and sewage from the Site prior to discharge via the return water flow to the Bristol WWTW.

Distillate Storage/Offloading

4.3.76. An area for distillate storage and offloading is included in Development Parcel 1, to supply the peaking plant. This is discussed in more detail later in this chapter.

Water Treatment, Demineralised Water Storage Tank

4.3.77. A waste water treatment plant, water treatment plant, and demineralised water storage tank are included in Development Parcel 1 (adjacent to the administrative / control building in Figures 4-2 and 4-3 (Volume III)).

4.3.78. The water treatment plant is designed to purify the boiler feed water, prior to use, and constitutes a building up to 6m height (14.5m AOD) and with a maximum footprint up to 33m by 14m. The boiler feed water is temporarily stored in a tank up to 9m height and 9m diameter.

Fire Fighting and Safety Provisions

4.3.79. The Applicant will include appropriate fire protection based on standard requirements, best practice, its own experience and input from the local Fire Officer and insurers.

4.3.80. During the detailed design phase, a Hazard and Operability (HAZOP) assessment will be carried out by the design engineers to ensure that fire risks are controlled. Where appropriate, buildings will contain firewalls and the main plant building and diesel storage tanks are designed to be physically separate to any adjacent building.

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4.3.81. The fire fighting building and fire/ raw water storage tank are likely to be in close proximity to the workshop, store and control buildings located towards the north of the Site.

4.3.82. As required by relevant legislation, standards and codes of practice, all fire fighting equipment and detection and protection systems will be to the standard necessary to gain the approval from the Applicant’s insurers and the Fire Officer.

4.3.83. The fire protection and detection systems for the Proposed Development may include but not be limited to the following techniques:

• Fire pumps and raw water tank;

• Connection to the existing Seabank 1 & 2 Power Station Site fire water ring main;

• Automatic cut-off valves on all fuel pump lines;

• Smoke/carbon monoxide (CO) detectors;

• Heat, spark and flame detectors at strategic locations;

• Fire hoses, to be stored in trace heated enclosures;

• Fire extinguishers;

• Fire alarms;

• Emergency lighting; and

• Use of fire retardant materials.

The Cooling System (Development Parcel No 2)

4.3.84. There is a requirement for a cooling system to condense the steam used in the power generation process once it has been exhausted through the steam turbine, to allow it to be pumped back to the boiler for re-use.

Cooling Water System

4.3.85. A number of different options have been considered in order to provide adequate cooling for the Proposed Development, including direct wet-cooling technology, hybrid-cooling technology and dry-cooling technology. The alternatives and reasoning for the chosen technology is outlined in Chapter 6: Project Need and Alternatives.

4.3.86. Hybrid-cooling technology has been chosen as the preferred method of cooling for the Proposed Development and the technology that is considered to represent the use of Best Available Techniques (BAT) for the plant. This is essentially a combination of dry-cooling and wet-cooling. Hybrid cooling is more efficient than

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air cooling but has a lower water demand than direct cooling and less visual impact than the use of natural draught cooling water system.

4.3.87. The lower water demand means that a supply of grey water from the Bristol WWTW can be used for supply – as is done for Seabank 1 & 2 – rather than abstracting larger volumes of water directly from the estuary, which was considered but rejected due to the ecological and archaeological sensitivities of the estuary and foreshore. This balance between the efficiency and the water use has therefore been agreed with the EA to represent BAT for the Proposed Development.

4.3.88. Up to two banks each of 12 cells will be installed onsite, resulting in up to 24 cooling water systems. As noted in Tables 4-1 and 4-2, the height of these cooling water systems is up to 19m above ground level (up to 27.5m AOD); noticeably less than the turbine and HRSG buildings.

4.3.89. The maximum flow of water to/from the Proposed Development (excluding Seabank 1 & 2) will be 600m3/hr, or 170kg/s, although once the water is supplied it becomes a closed system and only requires top up for condensation and evaporative losses (which constitutes about 1% of the total flow). Only during specified maintenance purge events and blowdown is the entire volume flushed through the system and recharged.

4.3.90. Water returned to the WWTW is expected to be on average 25-26 degrees Celsius (°C) when the CCGT Plant is in operation, or ambient when the plant is offline.

4.3.91. Due to the water being received from the treated outfall of the WWTW, there may be trace pollutant concentrations in the water up to the permit discharge limits specified for the WWTW outfall. It therefore requires chemical treatment before use in the cooling system, as described below, together with the addition of towns water to potentially dilute the chemical concentrations. The water returned to the WWTW is therefore generally expected to be in a better condition than when received; in a similar way the water from Seabank 1 & 2 is reportedly currently used by the WWTW operator (Wessex Water) to dilute its discharge into the Severn Estuary under its current discharge consent. Processed effluent from the Proposed Development will also be mixed with the cooling water returns and returned to the WWTW.

Cooling Water Dosing System and Chemical Treatment

4.3.92. The water received from the Bristol WWTW will be treated onsite in a water treatment plant within a dosing area. Water treatment chemicals will be added to ensure the water meets design standards for use in the cooling water system, with towns water used to dilute the concentrations, when required. This is a

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separate system to the water treatment for the boiler feed and will be up to 4.5m height (12.5m AOD) and with a maximum footprint of 20m by 10m.

Cooling Water Switchgear Building

4.3.93. The cooling water switchgear building will be up to 5.6m in height (14.1m AOD) and with a maximum footprint of 31m by 12m, located immediately west of the cooling water system in the northwest corner of the Proposed Development Site, adjacent to the dosing system and chemical treatment.

Water Supply Infrastructure (Development Parcel No 6)

Water Supply Pipeline and Infrastructure

4.3.94. The Proposed Development will require a pipeline to supply water for the cooling water system. The proposed pipeline will supply both Seabank 1 & 2 and Proposed Development via a new 800mm diameter polyvinyl chloride (PVC) pipeline entering the southwest corner of the Seabank 1 & 2 station.

4.3.95. The pipeline will split into two lines at this point, a 560mm pipeline supplying Seabank 1 & 2, and a 560mm pipeline to be routed around the western and northern perimeter of the existing Seabank 1 & 2 station (within the existing fence line) to the northwestern corner of the Proposed Development Site, as shown in Figure 4-1a (Volume III). The pipeline will be laid a minimum 1.2-1.5m below ground, as described in Chapter 5: Enabling Works and Construction.

4.3.96. The two existing pipelines between the Bristol WWTW and Seabank 1 & 2 (currently used for supply and return) will both be used as a return line for the existing station and Proposed Development. In this way a single, larger diameter pipeline can be installed and the two existing pipelines utilised to support both power stations.

4.3.97. The return cooling water flow from Seabank 3 will transported within a second pipe up to 560mm diameter that runs around the perimeter of Seabank 1 & 2 along the same route as the feed pipe. It will 'T' into the existing Seabank 1 & 2 pipework just north of the existing station boundary.

4.3.98. The new cooling water pipeline, once outside of the Seabank 1 & 2 fence line, is likely to follow the route of the existing water pipelines which is shown in Figure 3-1, (Volume III of this PEI Report). The proposed pipeline will be laid at a minimum depth of approximately 1.2 - 1.5m below ground level. This route was selected as the preferred option to minimise impacts on existing known environmental sensitivities, to minimise land owner disruption and to minimise construction length. The routing presented in Figure 4-1b (Volume III of this PEI Report) is a routing corridor 30m wide, with some widening to facilitate potential

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minor route variations within that corridor in the event of site specific conditions or sensitivities identified during construction, and to enable laydown areas to be used along the route for stringing of the pipeline prior to installation and the temporary storage of spoil.

Towns Water

4.3.99. The Proposed Development will be supplied by towns water from Bristol Water through an off take from the pipeline currently within the Seabank 1 & 2 site. It is estimated that 25,000m3 of water year will be required each year to fill up the water storage tank, which takes around 12 hours each month.

Peaking Plant with ‘Black Start’ Capability (Development Parcel No 3)

4.3.100. A peaking plant, also known as a ‘fast response generator’ is included as part of the Proposed Development.

4.3.101. A peaking plant is used to quickly increase or ‘top up’ the generating capacity during periods of increased need by the National Grid. It can be fired up at short notice to help cope with periods of high demand or low supply nationally (for example, when the wind is not blowing sufficiently to provide adequate electricity from the increasing number of wind farms in the UK). National Grid and DECC have confirmed a national need for UK fast response capacity (see Chapter 6: Project Need and Alternatives).

4.3.102. It is proposed that up to 240MWe of export capacity is installed as part of the Proposed Development. There are two types of peaking plant engines that could be used – open cycle gas turbines (OCGT) or reciprocating engines. Both are fast response units but each has its own advantages.

4.3.103. At this stage, it is not possible to select a preferred technology for use in the Proposed Development and therefore the choice of technology is being left open at the consenting stage. For the purposes of the PEI Report and the final ES, the worst case potential environmental effect of each technology has been assessed, for example air emissions, noise emissions or building massing.

4.3.104. It is proposed that the peaking plant engines would be housed in up to two buildings, as shown in Figures 4-2 and 4-3 (Volume III of this PEI Report), with the building dimensions sized to accommodate either type of engine. The OCGT are self-contained and do not therefore need to be enclosed within a building envelope, reducing the height and massing of this structure. For the purpose of this PEI Report the worst-case parameters have been assessed within each technical chapter, which in most cases will constitute an enclosed building up to 24m above the finished ground levels.

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4.3.105. The largest commercially available reciprocating engine is of the order of approximately 18MWe, which means up to 13 engines would need to be installed to achieve the 240MWe output. The exhaust flues from each engine would be ducted together into one or two stacks to minimise the visual effects of the reciprocating engines.

4.3.106. The largest commercially available OCGT is of the order of approximately 120MWe. The OCGTs are inherently enclosed within a prefabricated metal structure.

4.3.107. The peaking plant will be limited to a maximum of 1,500 hours per year and will have an efficiency around 40-45%. Based on the maximum permitted availability, the peaking plant would use approximately 24,000m3 of natural gas fuel per year.

4.3.108. The peaking plant would also provide the capability of being able to ‘black start’ the CCGT units without any assistance from the national electricity grid in the event of a total or partial shutdown of the national transmission system. The Proposed Development could then be used to help restart the national transmission system, whereas power stations without black start capability need to draw power from the transmission system to start operation.

4.3.109. A black start event would be an abnormal event, during which time the peaking plant would operate on distillate fuel. Once the CCGT units are operational the peaking plant would switch to natural gas. This process is estimated to take as little as 10 minutes and would therefore be a short-term, infrequent event.

4.3.110. The distillate fuel (for black start) would be stored onsite in up to two above ground bunded tanks within Development Parcel 1, typically cylindrical and each of up to 10m diameter by up to 12.5m height (21.0m AOD).

Utilities, Services and Landscaping Area (Development Parcel No 4)

Utilities and Services

4.3.111. A number of utilities current exist within the Proposed Development Site, which needs to be avoided or diverted.

4.3.112. The Abson gas pipeline, operated by National Grid Gas, which broadly crosses the Proposed Development Site in a southeast to northwest orientation, will need to be realigned as part of the enabling works described in Chapter 5: Enabling Works and Construction.

4.3.113. The diversion will be underground within the Utilities, Services and Landscaping Area, although it is a possibility that the pipeline may be brought above ground within the Site fence line, and will follow the route within the Utilities, Services and Landscaping Area that is south of the Generation Station Site (denoted on

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Figures 4-2 and 4-3 (Volume III of this PEI Report) to Seabank 1 & 2. If the pipe is installed above ground, the diverted gas pipeline will be placed on pipe racks approximately 1m wide and 2m high, as explained in Chapter 5: Enabling Works and Construction.

4.3.114. Subject to confirmatory engineering works being undertaken by National Grid, it is not currently expected that any substantial upgrades will be required to the network to deliver the necessary gas supply to the Proposed Development in addition to Seabank 1 & 2.

4.3.115. There is also an abandoned private water main that runs south-north across the Generating Station Site, which will require decommissioning prior to construction.

4.3.116. Both the diversion of the Abson gas pipeline and decommissioning of the water pipeline are further described in Chapter 5: Enabling Works and Construction.

Landscaping Works

4.3.117. Figure 17-15 (Volume III of this PEI Report) illustrates an indicative landscape masterplan for the Proposed Development, based on the maximum design parameters outlined in Table 4-1. In effect, this represents a worst-case scenario for the availability of areas for landscaping on-site; more land would be available if the final structures are less than the maximum dimensions illustrated above.

4.3.118. An 8m easement will be reserved along the length of the diverted Red Rhine channel, which Severnside Distribution Land Ltd is currently installing, to facilitate maintenance work by the LSIDB. It is intended that this would retained at existing site levels and would mainly comprise grassland, with some ruderal vegetation.

4.3.119. Elsewhere, a mixture of grassland, ruderal vegetation, and trees and shrubs will be planted.

4.3.120. The Utilities, Services and Landscaping Area will also contain the surface water attenuation needed to achieve pre-development greenfield rates for rainfall events up to and including the 1 in 100 year (inclusive of climate change). The surface water runoff generated within the Proposed Development Site will drain via a positive drainage system to an attenuation feature, or multiple features, with total capacity up to an estimated 3,800m2 (assuming an average 1m depth).

4.3.121. Figures 4-2 and 4-3 (Volume III of this PEI Report) show the current preferred layout for the water attenuation, which is a single water body, located between the gas receiving station and CCR Site. A linear water feature may also be incorporated along the southern boundary of the CCR Site adjacent to the PROW, as illustrated in Figure 4-2 and 4-3 (Volume III of this PEI Report) . This is shown in addition to the 3,800m3 requirement on the layout drawings, although

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it could enable the reduction of the size of the water body adjacent to the gas receiving station at the detailed design stage.

Watercourse Diversions (excluding the Red Rhine), Internal Roads and Access

Surface Water Drainage

4.3.122. Internal surface water drains will be required to transport surface water runoff to the proposed attenuation areas prior to discharge from the Site into the Red Rhine (via oil interceptors).

4.3.123. In the event of a fire, the firewater would be directed towards the attenuation pond and an electronic valve would automatically shut off the flow from entering the Red Rhine until it had been tested and deemed acceptable.

4.3.124. The DCO Application does not include the creation of the new Red Rhine channel. This is being undertaken by third party (Severnside Distribution Land Ltd) as part of their works to develop the wider Severnside area under the extant 1957/58 consent. The trenching of the new channel will be undertaken independently of the DCO Application and has been considered as part of the ‘future baseline’ as opposed to being ‘associated development’ to this Proposed Development, as discussed in Chapter 7: Assessment Methodology.

4.3.125. The diversion of the water flow from the existing Red Rhine channel into the new channel does form part of this DCO Application, as well as the diversion of a drainage ditch within the Site from the land to the south known as Crook’s Marsh.

Security Fencing

4.3.126. There will be a fence line around the perimeter of the Generating Station Site installed with closed circuit television (CCTV).

4.3.127. A gatehouse reception will be constructed at the northern perimeter of the Proposed Development Site where traffic will exit to the Spine Access Road, which will be manned 24-hours per day.

4.3.128. In the event that the Spine Access Road is not constructed, the primary access will be through Seabank 1 & 2 site, in the northwest corner of the Proposed Development Site. It is considered unlikely that the Spine Access Road will not be completed however, given that its construction is partly underway and for the purposes of this PEI Report it has been assumed to be in place by the time of construction of the Proposed Development.

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Car Parking and Cycle Storage Facilities

4.3.129. Operations staff will enter the Proposed Development Site via the new Spine Access Road through the main entrance in the centre of the Proposed Development Site. The access points are discussed in more detail later in this chapter.

4.3.130. Car parking facilities will be provided along the northern perimeter, with approximately 4 spaces next to the gatehouse, and remaining 15 behind the control, workshop, store and admin buildings.

Internal Roadways and Footpaths

4.3.131. There will be internal roadways within the Generation Station Site connecting infrastructure and access points.

4.3.132. There will be five vehicular access points to the Proposed Development Site during operation, as illustrated in in Figure 4-7 (Volume III of this PEI Report).

4.3.133. The main operational access route to the Proposed Development Site will be through the northern east perimeter of the Generating Station Site [Access Point 3, Figure 4-7 (Volume III)] via a proposed new Spine Access Road which Severnside Distribution Land Ltd intends to construct under the extant 1957/58 consent (currently under construction).

4.3.134. Secondary access to the road may also be constructed from the south along Ableton Lane [Access Point 5], although this is likely to be pedestrian or emergency vehicle access only.

4.3.135. Secondary access will also exist through the eastern perimeter of the CCR Site from an existing roundabout that will connect to the new Spine Access Road [Access Point 1], as well as at a second point further west along the Spine Access Road adjacent to the main access point [Access Point 2].

4.3.136. Direct access to the Site will also be available from Seabank 1 & 2 via an entrance in the northwest corner of the Proposed Development Site. In the event that the new Spine Access Road is not completed in time, this would be the main access point to the Site [Access Point 4].

4.3.137. As discussed above, an 8m easement will be left along the southern boundary of the diverted Red Rhine within the Proposed Development Site for access for maintenance by the LSIDB.

4.3.138. There are currently no PROWs within the Proposed Development Site, although a PROW currently terminates at the southern boundary of the Proposed Development Site.

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4.3.139. The Proposed Development will incorporate a new 3m wide footpath/ cycle path and 3m wide bridleway running form Ableton Lane, along the Utilities, Services and Landscaping Area in an easterly direction, and terminating at the existing roundabout that lies immediately east of the Proposed Development Site.

Lighting Columns and Lighting

4.3.140. The type, number and location of external lights for the operational phase will be carefully considered to take into account and minimise potential impacts to local residents and wildlife. All lighting will be implemented to minimise disturbance to important ecological receptors. The choice and implementation of lighting will be designed in line with current best practice for the reduction of intrusive light and avoidance of light pollution (e.g. Institution of Lighting Professionals (2011) ‘Guidance Notes for reduction of Intrusive Light GN01’) and seek to result in no significant additional off site light emission from the Proposed Development Site compared to the present situation.

Carbon Capture Readiness Land (Development Parcel No 5)

4.3.141. The potential future need for the installation of CCS technology and transport of CO2 off-site does not form part of this DCO Application. Any such works required for installation of CCS technology at some point in the future would be subject to separate planning consent or DCO consent as appropriate.

4.3.142. For the purposes of this DCO Application and in accordance with UK requirements, CCS will be considered through preparation of a standalone supplementary report to the DCO Application that addresses the requirements of the DECC CCR Guidance (Ref. 4-4).

4.3.143. In accordance with UK CCR requirements, the DCO Application incorporates an area set aside for the potential future installation of Carbon Capture technology. It is recognised that technological progress and developments in the regulatory framework for the use of carbon capture technology are likely to occur within the lifetime of the Proposed Development. Therefore, the design of the new power station has been developed with consideration for the possible future retrofitting of carbon capture technology at some future date.

4.3.144. The CCR requirement means that Applicants must demonstrate that CCS technology (of which there are 3 key types: pre-combustion capture, post-combustion capture and oxy-fuel combustion) has been considered as part of the DCO Application and that there is sufficient land available and remaining available for the future retrofit of that technology in the event that it is commercially proven at some point in the future, i.e. that the Proposed Development is considered Carbon Capture Ready (CCR).

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4.3.145. CCR needs to be demonstrable for all new generating stations with a generating capacity at or over 300MW and of a type covered by the European Union Large Combustion Plant Directive as set out in section 4.7 of the Overarching NPS for Energy (EN-1).

4.3.146. As such, an approximate area of 6.3ha denoted the CCR Site has been reserved to the east of the Generating Station Site (see Figure 3-1, Volume III of this PEI Report) to allow for the potential future provision of CCS technology. Any future installation of carbon capture technology would be subject to a separate formal consent application at the time, since the details associated with any such technology are not yet available. For the purposes of this DCO Application therefore, only a high level evaluation of carbon capture readiness has been undertaken in accordance with the CCR requirements (presented as a separate, standalone report to the final ES).

4.3.147. This CCR Site will be temporarily used for siting of the construction compound and laydown during the generating station construction phase. This area will accommodate construction work force welfare facilities, construction laydown area, security gatehouse, internal roadways and footpaths as well as lighting. This is further discussed in Chapter 5: Enabling Works and Construction.

4.3.148. Post construction, the CCR Site will be reinstated to grassland, with relatively little or no other vegetation, hence returning it to a similar state to its current baseline. The ecological value of this land will be maintained in accordance with the CCR Directive (Ref. 4-3), which states that “the land would not be available for long term mitigation’ and ‘not allowed to become a wildlife reserve through neglect or mismanagement”.

Grid and Utility Connections (Development Parcel No 7)

4.3.149. The Proposed Development will require a connection to the existing Seabank Substation to export the electricity generated by the power station, as described below. The information relating to the proposed grid connection will also be presented in the Grid Connection Statement that will accompany the DCO Application.

Electricity Substation and Grid Connection

4.3.150. The Proposed Development will export electricity to National Electricity Transmission System (NETS) via the existing Seabank 400kV substation. A grid connection agreement for 1,200MWe from 31 October 2019 is already in place with National Grid (the administrating and operating authority of the NETS) and the Applicant is seeking to extend this by an additional 200MW.

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4.3.151. Two separate connection circuits will link the Proposed Development 400kV switchyard to the Seabank Substation.

4.3.152. The electrical connection will extend approximately 440m south of the Proposed Development Site, through existing Seabank 1 & 2 site (within the fence line), to the Seabank Substation.

4.3.153. It is envisaged that the connection would be via above ground cables, on an aerial cable bridge rack approximately 2m above ground to avoid existing equipment within Seabank 1 & 2. However the option for Horizontal Directional Drilling (HDD) beneath the Seabank 1 & 2 infrastructure remains a possibility and has also been assessed in the EIA. Further information on construction methods is provided in Chapter 5: Enabling Works and Construction.

4.3.154. The connection infrastructure that will also be constructed by the Applicant as part of the Proposed Development will comprise the following main elements:

• Up to five generator transformers to step-up the voltage to 400kV;

• 400kV gas-insulated switchgear ("GIS") connecting the output from the generator transformers to the two connection circuits within the Proposed Development Site;

• Two generator connection bays with GIS to connect the 400kV connection circuits with the 400kV substation busbars at Seabank substation; and

• A fibre optic cable that will also be installed with the power cable circuit to carry essential control and protection data as well as telecommunications data to satisfy National Grid requirements.

4.3.155. In parallel with – but separate to - this DCO Application, National Grid is currently proposing the connection of an additional 400kV circuit into Seabank Substation for the network reinforcement required for the proposed Hinkley C nuclear power station, which will include the extension of the existing substation building and associated foundations will accommodate five new bays.

4.3.156. The plans by National Grid are independent from this DCO Application and are not considered ‘Associated Development’ to the Proposed Development. They are discussed in terms of cumulative impacts in each technical assessment where appropriate. Further information is presented in Chapter 7: Assessment Methodology.

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Towns and Foul Water Connections

4.3.157. Development Parcel 7 includes an approximately 100m wide corridor within the northern boundary of the Seabank 1 & 2 site within which to connect the Proposed Development to the towns water and foul water services.

4.3.158. The foul water will be treated onsite in the WWTP and discharged into the return flow pipe with the cooling water to the Bristol WWTW.

Ancillary Development

4.3.159. The Planning Act 2008, Section 120, defines ‘ancillary development’ as a range of matters including acquisition of land, intrusive works and other connections and agreements. These will be considered and documented in the DCO application

4.4. Hours of Operation and Shift Pattern

4.4.1. It is envisaged that plant operation will be a continual process, operating twenty-four hours per day, seven days per week with periodic offline periods for maintenance.

4.4.2. As mentioned previously, the actual running hours will be subject to the electrical demand, however based on current projections it is anticipated that the CCGTs will operate at around a 31% load factor (an average 2,716 hours per year) over the course of the plant lifetime. However, for fuel capacity purposes and conservative assessment purposes, it is assumed that 90% availability is achieved.

4.4.3. The plant will be designed to operate continuously for an expected period of at least 30 years after which on-going operation will be reviewed and if it is not appropriate to continue operation the Proposed Development Site will be decommissioned.

4.5. Employment

4.5.1. It is estimated the Proposed Development if operated independently of Seabank 1 & 2 will provide approximately 40 full time equivalent (FTE) operational jobs, as summarised in Table 4-3. If the Proposed Development was operated in conjunction with Seabank 1 & 2, approximately 22 additional staff would be required.

4.5.2. Given the nature of power station operation, it is likely that the employees will be working in shift patterns, with approximately 4 employees per shift (depending on fuelling operation) and the remainder in normal working hours roles. There would be three shifts per day, with the first shift starting at 06:00 hours.

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Table 4-3: Provision of Employment during Operation Position Number Skill Level

Shift Operative 12 Level of expertise comparable to existing boiler/turbine operators

Maintenance Controller 2 Level of expertise comparable to existing fuel

operatives Operations Technician 12 Degree qualified mechanical engineer

Maintenance Technician 8 Craftsman level

Chemist 2 Commercial position Corporate 4 Assistant level Total 40 -

4.5.3. In addition, temporary and contractor employees associated with fuel deliveries and maintenance activities will be required for the operation of the Proposed Development.

4.6. Nuisance Control

4.6.1. Lighting of the Proposed Development Site is required for security and safety purposes and will meet the reasonable requirements of the local authority to avoid impacts upon local residents and road users. This is discussed further in Chapter 17: Landscape and Visual.

4.6.2. Noise levels will be regulated as defined in Section 72 of the Control of Pollution Act 1974 (amended 1989) (Ref. 4-7) and conform to British Standard ISO 140-4 (1998) and those detailed within any Requirements as part of the DCO. An annual noise survey will be carried out onsite and any noise complaint will be investigated and addressed. This is discussed in more detail in Chapter 12: Noise and Vibration.

4.6.3. As the generating station will be fired on natural gas, the potential for dust emissions during operation will be low. During construction, there is the potential for dust generation from any soil clearance activities and the importation and levelling of material for land raising, for example. Mitigation measures are presented in Chapter 11: Air Quality.

4.7. Operational Waste Streams

4.7.1. This section discusses the potential for operational waste. Construction waste is discussed in Chapter 5: Enabling Works and Construction.

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4.7.2. During the operational phase there is not expected to be any significant waste associated with the Proposed Development. The key waste streams include those outlined in Table 4-4.

4.7.3. Waste water generated from cooling and boiler blowdown is described further in Chapter 14: Flood Risk, Hydrology and Water Resources. During commissioning, boiler acid washes will be required. For the boiler acid washes the volume is effectively the volume of the boiler, plus a rinse. This is estimated at around 1,200m3 of waste liquid during commissioning, which will be neutralised and tankered offsite.

Table 4-4: Expected Waste Streams associated with the Operational Proposed Development Waste Description Quantity (tonnes per

year) Management

Oil from oil/water separators (liquid) 0.5 Recycled

Sludge from oil/water separators (solid) 3 Recycled

Transformer oils 20-30 Recycled Oil filters 1 Special waste landfill Oil contaminated material 2 Special waste landfill Batteries (lead) 0.25 Special waste landfill Fluorescent tubes and lamps 0.4 Special waste landfill Biodegradable wastes (grass etc.) 3 Recycled

Air filters 5 Municipal landfill Sewage sludge 120 Sewage treatment plant Timber (packaging) 7 Recycled Mixed metal waste 5 Recycled Turbine and blade washings 15 Sewage treatment plant Waste oil 5 Recycled

General waste 25 Part recycled at MRF / municipal landfill

Glass 2 Recycled Ion exchange resins 15 (5year cycle) Recycled

4.8. Chemical and Utility Usage

4.8.1. Table 4-5 summarises the anticipated chemical usage during operation.

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Table 4-5: Utility Usage

Utility Consumption Yearly

Units Value

CCGT Cooling Water tonnes 6,000,000

CCGT Electricity (Auxiliaries) kWh (kilowatt hour) 350,000,000

CCGT Diesel (Emergency Generators) m3 20

CCGT Nitrogen m3 4,000

Demineralisation

Scale Inhibitor kg 60,000

Sulphuric Acid kg 280,000

Caustic Soda kg 40,000

Chlorine kg 30,000

Cooling Water System

Glycol kg 60,000

Corrosion Inhibitor kg 15,000

Antibacterial agent kg 3,500

Steam Cycle

Ammonia kg 10

Oxygen Scavenger kg 1,500

Tri Sodium Phosphate kg 30

4.9. Safety and Emergency Planning

4.9.1. The Proposed Development could potentially be operated by the existing Seabank 1 & 2 Operations and Maintenance teams and will utilise external expertise from the equipment vendors and specialist advisors when required.

4.9.2. The Applicant will develop an Emergency Planning and Response Management Plan similar to that used for Seabank 1 & 2 site such that emergency planning and response control measures are implemented to:

• Mitigate the potential effects to persons, environment, assets or company reputation;

• Respond to catastrophic plant and process incidents such as fires, explosions, release of hazardous substances or large releases of energy;

• Respond to external incidents which have the potential to cause incidents described above e.g. nearby facility emergency, flood, malevolent actions, earthquake or aircraft crash; and

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• Communicate with stakeholders such as neighbours, media or regulators.

4.9.3. The Emergency Planning and Response Management Plan will be tailored to the Proposed Development. This Plan is applied at all operational SSE sites and includes any site specific requirements.

4.9.4. Fire safety methods will build upon those methods already practiced at the Seabank 1 & 2 site. Fire safety management is applicable to the entire Generation Station Site and is further addressed in this section.

4.9.5. Measures will be taken to minimise the risk of fire during site enabling, construction, operation and decommissioning. The precise nature of these measures will be determined following detailed engineering. The key potential fire risk aspects of the Proposed Development are:

• Storage of distillate fuel; and

• Storage of flammable consumable materials (e.g. maintenance oil).

4.9.6. Consumable materials will be stored in bunded controlled areas and storage volumes will be minimised where possible. Due consideration will be paid to the appropriate legislation and guidance.

4.10. References

Ref. 4-1 DECC (2011) Overarching NPS for Energy (EN-1) Ref. 4-2 The Planning Inspectorate (2012). Advice Note 9: Rochdale Envelope Ref. 4-3 Official Journal of the European Union (2009) Directive 2009/31/EC of

the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide

Ref. 4-4 DECC (2009); Carbon Capture Readiness (CCR), A guidance note for Section 36 Electricity Act 1989 consent applications

Ref. 4-5 European Commission (2010) Industrial Emissions Directive (IED) Ref. 4-6 The Environmental Permitting (England and Wales) Regulations 2010 Ref. 4-7 HMSO (1974); Control of Pollution Act (amended 1989)

May 2014 Page 4-32

Seabank 3 PEI Report – Chapter 5 Enabling Works and Construction

May 2014 Page 5-1

5. Enabling Works and Construction

5.1. Introduction

5.1.1. This chapter of the PEI Report presents an overview of the enabling works

required for the preparation and construction of the Proposed Development and

associated infrastructure. A description of the operational development is

provided in Chapter 4: Project Description.

5.1.2. Enabling and construction works are anticipated to last approximately 4 ½ years.

An indicative construction programme is presented in Section 5.3.

5.1.3. A Construction Environmental Management Plan (CEMP) will be produced and

implemented prior to the onset of the construction phase to maintain

consideration of environmental effects beyond the consenting stage of the

Proposed Development and associated infrastructure. The appointed

construction contractor will be required to adhere to the CEMP, which will give

due regard to the sensitive environmental receptors as identified within each

technical chapter. A framework for the CEMP is provided in Appendix C, Volume

II of this PEI Report, which will be populated and agreed with SGC and BCC

following receipt of the DCO and prior to enabling works commencing onsite.

5.2. Enabling Works

5.2.1. There are currently no buildings/structures located in the DCO Site, therefore no

demolition works will be required as part of this Proposed Development and

associated infrastructure.

5.2.2. There are a few ash trees and shrubs within the Proposed Development Site,

which will be removed following the appropriate permissions and ecological

checks; the need for compensatory planting at another location has been

assessed as part of this EIA and is discussed in Chapter 16: Ecology.

5.2.3. The disused railway tracks in the northwest corner of the Proposed Development

will also require decommissioning. These abandoned tracks will be dug up and

removed from the Site before any of the following works.

Contractor Laydown/Accommodation

5.2.4. The CCR Site will be levelled and gravelled at the start of the construction

programme in preparation for laydown and Contractor accommodation.


May 2014 Page 5-2

Diversion of Existing Services within the Proposed Development Site

5.2.5. It will be necessary to divert some of the existing on-site services and utilities in

order to construct the Proposed Development and associated infrastructure,

which are illustrated in Figure 3-3, Volume III of this PEI Report.

Water Main

5.2.6. There is a redundant private water main that runs south-north across the

Generating Station Site which used to serve the former Terra Nitrogen and ICI

site. For a single-shaft generating station this water main would need to be

diverted, as it is currently running below the location in which the HRSGs are

proposed to be located. For a multi-shaft arrangement it may be possible to

construct around this water main and avoid the need for it to be diverted. This

pipeline will be surveyed /located and, either decommissioned in-situ with a new

pipeline installed to divert the flow round the Proposed Development, or a trench

(approximately 3-5m wide) opened to excavate the pipe which will be removed

and decommissioned.

Abson Gas Pipeline

5.2.7. Diversion will be required to the Abson gas pipeline which broadly crosses the

Proposed Development Site in a southeast to northwest orientation.

5.2.8. The National Grid ‘F14 feeder’ does not require diverting and is therefore not

discussed further below.

5.2.9. The Abson gas pipeline runs from the southeast corner of the Proposed

Development Site and crosses to the southwest corner, before rising above

ground in the northeast corner of the Seabank 1 & 2 site. The pipeline transports

gas from Abson to Severnside and runs through areas designated for

development and will require diverting.

5.2.10. It is recorded on the pipeline route map that the pipeline through the Proposed

Development Site was installed by Horizontal Directional Drilling (HDD), in two

drills, to allow it to pass under an existing 24” water main and other buried

services on the site. Based on HDD profile drawings, the gas pipeline will be at a

depth of around 10m across much of the Site.

5.2.11. The Abson pipeline will be surveyed /located and cut in the eastern part of the

Proposed Development Site. New pipe spools will be installed using trenching

techniques to divert the Abson pipeline within the Utilities, Services and

Landscaping Area, as illustrated in Figure 4-1a, Volume III of this PEI Report).

The trench would be approximately 3-5m wide 4m deep, within a 20m

construction corridor. Once within the Site fence line the gas pipeline will either


May 2014 Page 5-3

continue below ground or will be laid on a pipe rack approximately 2m above

ground level (up to 10.5m AOD). The existing pipeline would be left in-situ

beneath the Proposed Development Site.

Overhead Lines

5.2.12. It will be necessary to divert an 11kV overhead line (OHL) that currently crosses

the eastern edge of the Generating Station Site in a northeast to southwest

direction.

5.2.13. Western Power Distribution will undertake the diversion, installing it underground

through the centre of the Site, most probably alongside one of the internal access

roads. The exact route of the cable will be determined during the detailed design.

5.2.14. The 400kV and 132kV OHLs that cross the Proposed Development Site will not

be diverted.

Diversion of Red Rhine

5.2.15. As mentioned previously within Chapter 4: Project Description, the DCO

Application requires the diversion of the water flow from the existing Red Rhine,

to a new channel located outside along the northern boundary of the Proposed

Development.

5.2.16. The water flow will be diverted using earth bunding within the existing Red Rhine

to allow the flow to move into the dry channel. Only when the new channel has

been stabilised will the existing Red Rhine will be dewatered and filled in.

Land Raising

5.2.17. For flood protection purposes, it is expected that the Generating Station Site will

need to be raised up to 8.31m AOD (an average 2.0m rise in ground level).

However in order to provide sufficient flexibility for the Contractor who may be

unable to guarantee a finished level to this level of precision, the DCO Application

allows for a finished ground level up to 8.5m AOD within the Generating Station

Site, as illustrated in Figure 5-1 (Volume III of this PEI Report). The justification

for this is presented in Chapter 13: Flood Risk, Hydrology and Water Resources.

5.2.18. Other parts of the Proposed Development Site and the Other DCO Land do not

require raising for flood protection.

5.2.19. It is estimated that circa 158,000m3 of material will be required to raise the Site,

depending on whether the entire Generating Station Site is raised to a consistent

8.5m AOD level. It has been assumed that this material will be imported over a 6

month time period (to avoid significant effects on the local road network), and that

all material will be transported to site by road.


May 2014 Page 5-4

5.2.20. The fill would arrive in loads with a minimum capacity of 10m3, which would result

in approximately 15,800 additional HGVs entering/leaving the Proposed

Development Site per day. The effect of this on traffic flows on the public

highways is discussed in Chapter 10: Traffic and Transport.

5.2.21. This is a worse case assumption; it is expected that the finished site levels will be

less than this elevation to allow the Contractor to lay a 300-550mm gravel or

concrete bed in order to achieve a finished floor level of 8.31m AOD, and certain

infrastructure such as the cooling water system is inherently bunded and could be

constructed at current site levels without the need for any land raising.

5.2.22. It should be noted that if the finished ground level when built is less than 8.5m

AOD, the maximum height of the structures and stacks can also reduce.

5.2.23. The topsoil will be stripped, stockpiled and retained for landscaping prior to land

raising.

Proposed Cooling Water Pipeline

5.2.24. As outlined in Chapter 4: Project Description, a new cooling water pipeline will be

required from the WWTW, approximately 3.5km south of the Site (as the crow

flies). This pipeline will be approximately 4.5km and will be buried a minimum 1.2-

1.5m underground.

5.2.25. For the purposes of the DCO Application the cooling water pipeline is considered

to be Associated Development to the Proposed Development as defined under

Part 3 to the Planning Act 2008. The necessary easements and permissions for

the construction of this pipeline will therefore be sought under the DCO.

5.2.26. It is intended that the water pipeline would be constructed and owned by Wessex

Water. Article 6 of the draft DCO would allow the Applicant to grant or transfer

any of the benefit of the provisions of the DCO to another entity. Any benefits or

rights conferred this way would be subject to all the same liabilities and

obligations as under the DCO.

5.2.27. The indicative routing corridor of the proposed cooling water pipeline is shown in

Figure 4-1a and Figure 4-1b (in Chapter 4: Project Description).

5.2.28. In preparation for laying the cooling water pipeline, the following key pre-

construction processes will be performed:

• Liaison with key local stakeholders and potentially affected landowners;

• Completion of a pre-construction survey to:

o Mark out the pipeline construction corridor, third party services and

the need for any other special crossings; and


May 2014 Page 5-5

o Provide a photographic record of the entire route including key

operational and environmental features and aspects.

• Completion of additional environmental surveys required (e.g. post

consenting surveys);

• Evaluation and implementation of agreed pre-construction environmental

mitigation measures;

• Marking of all crossing points of buried services and any environmental

resources to be protected;

• Excavation of trial holes along key points of the route to confirm the

suitability of localised underlying ground conditions;

• Establishment of temporary access tracks along the construction working

width (including bridging of existing ditches to provide temporary working

access where required); and

• Implementation of security and health and safety arrangements, such as

the provision of signage and infrastructure.

5.2.29. Once the pre-construction activities have been completed the works required to

install the proposed cooling water pipeline would commence. These are outlined

in section 5.3 of this chapter.

5.3. Construction Phase

5.3.1. Measures for site preparation and construction are necessarily broad at this

stage and may be subject to modification during any future detailed construction

planning. For this reason, the following assessment is based on an envelope of

works and reasonable assumptions for the construction programme and the

collective experience of the EIA and Design Team with similar projects,

particularly in relation to the phasing of the Proposed Development and


5.3.2. Potential construction environmental effects identified within this chapter are

discussed in more detail in each of the corresponding technical chapters (i.e.

Chapters 9 to 19).

Programme of Works

5.3.3. Allowing sufficient time for the granting of DCO consent and to address expected

requirements, it is anticipated that the earliest enabling works would be mid 2015,

with a commissioning date in late 2019. It is the current intention though that the

DCO should allow sufficient flexibility for the construction to start anytime within 7

years of receipt of the Order, which would be anytime between 2015 and 2023.


May 2014 Page 5-6

The Applicant’s current best estimate though is that it will target a 2021

commissioning date.

5.3.4. The main activities to be undertaken and the approximate duration of the works

are outlined in Table 5-1. Table 5-1 presents an indicative programme for the

construction works; however the actual programme will be subject to contractor

specifications.

5.3.5. Both the enabling works and construction total approximately 4 ½ years

(approximately 54 months), based on the Applicant’s current best estimates.

5.3.6. Enabling works are anticipated to require approximately 17 months and be

complete by 2019. The subsequent construction and commissioning phase will

having an estimated minimum duration of around 37 months, assuming the entire

Proposed Development is built rather than using a phased approach. Depending

on market conditions the Applicant may prefer to construct the Proposed

Development in phases over a longer period of time, or delay the start date in line

with the requirements of the DCO.

5.3.7. Based on current estimates, the peak period of construction is expected to occur

in late 2019, which represents the initial construction of the Generating Station

Site.

5.3.8. A Principal Contractor will be appointed by the Applicant for the works and they

will be held responsible for the implementation of a Construction Method

Statement (CMS) and the CEMP, through which compliance with The

Construction (Design and Management) Regulations (2007) (Ref. 5-1) will be

achieved.


May 2014 Page 5-7

Table 5-1: Indicative Enabling and Construction Programme

2017 2018 2019 2020 2021

Activity Weeks

EN

AB

LIN

G W

OR

KS

Leveling of CCR Site and preparation for laydown

26

Diversion of existing utilities

26

Diversion of Red Rhine watercourse

26

Preparation and Land Raising

60

CO

NS

TR

UC

TIO

N

Generating Station Site

144

Peaking Plant 12


96

Electrical Grid Connection Infrastructure

4

Landscaping 52

Commissioning 4

Hours of Work

5.3.9. It is anticipated that the core working hours for construction will be as follows:

• 07:00 – 19:00 hours weekdays;

• 07:00 – 13:00 hours Saturday; and

• Working on Sundays and Bank Holidays will be subject to reasonable

notice.

5.3.10. It is likely that some construction activities will be required to be 24 hours during

the peak periods; therefore this has formed the basis of the assessments

contained within this report, unless specified otherwise. Where on-site works are

to be conducted outside the core hours they will comply with any restrictions

agreed with SGC and/or BCC, and in particular regarding control of noise and

traffic.

5.3.11. Some technical chapters assume deliveries outside these hours to present worse

case scenarios.


May 2014 Page 5-8

Construction Workforce

Proposed Development

5.3.12. It is estimated that during construction, there will be a maximum of 800 personnel

contracted to work onsite on any given day. Plate 5-1 illustrates that the

personnel resource is expected to peak around two years into the construction

schedule, which based on Table 5-1 is envisaged to be during the second to

fourth quarters of 2019.

5.3.13. Chapter 10: Traffic and Transport discusses the transport options available to

employees for travel to and from work.

Plate 5-1: Estimated Personnel Onsite during Construction (Post Enabling Works)

Associated Development Infrastructure

5.3.14. It is expected that approximately 100 additional workers to the numbers

presented above will be required during construction of the cooling water pipeline

and electrical connection.

5.3.15. The construction period for the cooling water pipeline is anticipated to be

throughout 2020 to 2021 and to take approximately 24 months to complete. The

electrical connection will run over a 4 week period within this timeframe.


May 2014 Page 5-9

5.3.16. Consideration has been given to the types of plant that are likely to be used on-

site during the site preparation and construction phase of the Proposed

Development and associated infrastructure. The plant and equipment associated

with each key element of the construction process is set out in Table 5-2. The

table also includes the maximum number of mobile work plant required at any

one time during the construction programme.

Table 5-2: Estimated Plant Type and Equipment during Construction Activities

Plant

Number of Plant

Proposed Development


360 Excavator 5 5

Bulldozer 6 1

Dumper 6 3

Paver 8 -

Roller 3 -

Crane 4 -

Compressors 6 1

Cherry Pickers 8 1

Hoists 3 1

Fork Lift Trucks 4 -

Concrete Delivery Trucks 25 -

Concrete Pumps 2 -

Heavy Goods Vehicles (HGVs) (delivering and collecting)

6 4

Piling Rigs 4 -

Generators 5 -

Pumps 2 1

Tipper Wagons - 3

Road Vechles - 1

HDD Drilling rig - 1

Laydown and Contractors Compound Areas

5.3.17. It is proposed that the laydown and contractors compound areas will be located in

an area of approximately 4ha in the eastern side of the Proposed Development

Site. 3ha of this area will be located in the CCR Site (see Figure 5-2, Volume III

of this PEI Report), with the remainder in part of the proposed Utilities, Services

and Landscaping Area.

5.3.18. Construction material for delivery and storage will be located in the northern

border of the CCR Site to avoid material having to pass under the existing


May 2014 Page 5-10

overhead power lines. The chemical and flammable storage area/ services hub

(power/water/sewage) and secure equipment storage will all be located on the

western side of the CCR Site. The contractor compound, including approximately

40 cabins, will be located in the northeast of the CCR Site. A temporary car park,

with a maximum capacity of approximately 400 spaces, will be located to the

southeast of the CCR Site, with entrance/exit from Access Point’s 1 and 2.

5.3.19. The laydown and contractor areas will be connected with a temporary access

road, as illustrated in Figure 5-2, Volume III of this PEI Report.

5.3.20. The laydown area within the CCR Site will also be used for storing the cooling

water pipeline materials. Additional laydown and spoil material stockpiles could

occur anywhere along the Other DCO Land, adjacent to the proposed pipeline.

5.3.21. Following the end of construction, the laydown and contractor areas on the CCR

Site will be reinstated to grassland using the stored top soil that was stripped at

the start of construction. The ecological value of this land will not be improved as

the EU CCS Directive Guidance (Ref. 5-2) states that “the land would not be

available for long term mitigation’ and ‘not allowed to become a wildlife reserve

through neglect or mismanagement”.

5.3.22. Additional laydown areas required along the cooling water pipeline will be

reinstated as detailed in paragraph 5.3.57.

Transportation of Material and Equipment

5.3.23. Transportation of construction material to and from the DCO Site will be via

existing trunk and local networks (A4 and A403) Deliveries of construction

materials will predominantly be by HGVs.

5.3.24. The peak number of vehicle movements is expected to occur during 2019 for the

purposes of the assessments.

5.3.25. Major plant equipment (abnormal loads) including, for example parts of the boiler

and steelwork associated with the turbines, will be delivered to the Site via routes

identified in Chapter 10: Traffic and Transport. It is not possible at this stage to

identify the exact number and size of such loads, as these will be dependent on

the supplier of the plant, which is yet to be determined. Typically no more than

20-30 abnormal deliveries are required for a project of this nature. Such loads will

be identified in advance to the local authorities, and suitable routes and delivery

times agreed to minimise any potential disruption. It is not envisaged that any

deliveries will require any modifications to public roads and all deliveries will

comply with UK road regulations.


May 2014 Page 5-11

Traffic Management

5.3.26. Estimated numbers of construction related vehicle journeys for the 37 month

construction period have been calculated based on volumes of estimates

construction material. A full impact assessment of the construction vehicle

movements on the surrounding road network is presented within Chapter 10:

Traffic and Transport.

5.3.27. Unapproved parking on the public roads will not be allowed and the site labour

force will be encouraged to use public transport. Any local traffic management

measures for site access will be agreed in advance of site works commencing

with SGC and BCC.

5.3.28. Primary access and egress during enabling works and construction will be via the

northwest perimeter of the CCR Site, connecting to the proposed new Spine

Access Road (see Figure 5-2, Volume III of the PEI Report), which Severnside

Distribution Land Ltd intends to construct under the extant 1957/58 consent.

5.3.29. Additional vehicular access will be available from the south along Ableton

Lane/Minor’s Lane, as well as through the eastern perimeter of the CCR Site

from an existing roundabout that will connect to the new spine access road

(Figure 5-2, Volume III of the PEI Report).

5.3.30. A secure construction compound will be developed in advance of site works. This

would include site welfare for operatives. Pedestrian, site and traffic management

plans will be drafted and clear routes established so that vehicle routes within the

DCO Site are clear.

5.3.31. It is anticipated that the construction of the Proposed Development would lead to

up to a maximum of 40 HGV deliveries (80 movements) per day during peak

construction.

Piling and Foundations

5.3.32. Certain areas within the Proposed Development Site are expected to require

below ground foundations and piling.

5.3.33. The infrastructure that is likely to require below ground foundations (and their

depth) is, as follows:

• Transformers (1000mm);

• Turbine and HRSG (2000-2500mm);

• Cooling Water Pumping Pits (3000-4000mm) and Pipework (2000mm);

and


May 2014 Page 5-12

• Water tanks (1000mm)

5.3.34. Where piling is required, Continuous Flight Auger (CFA) / bored piling will be

implemented, which generates less noise than other types of piling (such as

impact or vibro-piling). CFA piling comprises drilling prefabricated piles into the

ground and pumping in concrete as the drill bit is removed.

5.3.35. Groups of piles will be connected by a pile cap (a large concrete block into which

the heads of the piles are embedded) to distribute loads which are larger than

one pile can bear.


5.3.36. As part of the Associated Development Infrastructure a new cooling water supply

pipeline will need to be installed for the Proposed Development Site. Ultimately,

water will be supplied from and returned to the Bristol WWTW, although the

supply and return pipelines will be routed via the existing Seabank 1 & 2 facilities.

5.3.37. A feasibility assessment was carried out to determine the preferred route,

configuration and diameter of the supply and return pipelines. It is currently

anticipated that as part of the associated infrastructure a new single 800mm

diameter pipeline will be required between Seabank 3 and the Bristol WWTW.

This pipeline will follow the route of the existing supply and return water pipeline

shown on Figure 1-2 (Volume III of this PEI Report). There will also be new

cooling water supply and return lines installed to connect the Proposed

Development to Seabank 1 & 2. It is anticipated that these will run around the

inside perimeter of the existing site.

5.3.38. The following information outlines the likely construction methods for the cooling

water pipeline, although Wessex Water will be undertaking the detailed design

study and installation of the proposed pipelines.

Trench Excavation

5.3.39. Trenching techniques will be used to install the new cooling water supply pipeline

underground to a depth of approximately 2 - 4m. The cooling water pipeline will

be laid within a the proposed cooling water pipeline corridor within the Other DCO

Land; an approximate 10m standoff distance from the existing Wessex Water

pipelines is required.

5.3.40. Figure 5-3 (Volume III of this PEI Report) illustrates the trenching methods likely

to be used.

5.3.41. The width of trenches will depend upon the location of the stretch of excavation.

For a length through fields the trenches would be between approximately 3m and

5m. For excavation in roads, the trenches would be sheeted (a vertical cut each


May 2014 Page 5-13

side of the trench with support from steel sheets) to allow a trench width of 1-

1.5m.

5.3.42. A construction corridor of 20m will be established within the Other DCO Land to

allow areas for soil piles, laydown, and vehicle access.

5.3.43. Excavated materials will be stored adjacent to the trench to enable it to be used

for restoration of the site following the laying of the pipeline.

Lowering and Laying

5.3.44. Prior to lowering-in, the trench will be prepared to accept the pipe. Surface rocks

or debris that could damage the pipe coating will be removed from the trench.

Suitable selected material, imported fill or packers will be carefully placed in the

trench bottom prior to the pipe laying process. The excavated pipeline trench will

be checked to ensure that the pipe will be laid with the correct cover and that the

pipe will not be damaged during installation.

Special Crossings

Streams and Ditches

5.3.45. Crossing of streams, ditches and rivers will either be by boring/drilling under the

watercourse or by open trenching (using either a wet or dry technique) if

necessary. The choice of method will depend upon several considerations

including the size, nature and location of the watercourse.

5.3.46. For the dry technique upstream and downstream temporary dams of steel sheet

piling or “sandbags” will be formed and the flow piped or pumped around the

temporary obstruction formed by the coffer dams. The pipe trench will then be

excavated in the dry and the pipeline constructed in the normal way. Afterwards

the temporary dams and appurtenant work will be removed and the bed and

banks reinstated to their original condition.

Road Crossings

5.3.47. There are expected to be around six crossings at the roads listed below:

• Severn Road

• Chittening Road

• Washingpool Lane

• Mooreend Farm Avenue

• Poplar Way E; and

• Lawrence Western Road.


May 2014 Page 5-14

5.3.48. At road crossings the cooling water pipeline will be sheet trenched to a depth of

1m using sheet trenching to minimise the width of the trench, as described

above.

Railway Crossing

5.3.49. The cooling water pipeline between the Bristol WWTW and Seabank 1 & 2

crosses underneath an existing railway track at grid reference 353071, 180910

(x,y) and will need to be bored or drilled sing HDD under the embankment. After

consultation with Network Rail, it was established that monitoring would be

undertaken within 3m (at a 45 degree angle) either side of the track, before,

during (drilling only) and after works have been completed.

5.3.50. A steel pipeline sleeve is also required with 10m clearance from the crossing

either side of the track to safeguard the pipeline from water damage. With the

sleeve the pipeline will be approximately 900mm in diameter and must be

trenched at least 4.3m below the sleeper.

Utilities

5.3.51. The cooling water pipeline also crosses a number of utility services and pipelines.

A detailed utilities search will be undertaken before construction.

5.3.52. Five of these crossings are with Government Pipeline and Storage System

(GPSS) pipelines. Details of each of these crossings are as follows:

• Crossings 1 to 3 are located on the Hallen to Avonmouth (HA) line (ST

530 858 0928):

o HA1 is located on the north side of the railway at a measured depth

of 1.5-1.8m depth (varies) with an estimated 12-20” diameter;

o HA2 is located beneath GPPS(1) at an estimated depth of 2m; and

o HA3 is an abandoned pipeline located on the south side of the

railway, approximately 6-10” diameter.

• Crossings 4 and 5 are located on the Chittening to Berwick Wood (CB)

line (ST 534 6581828). CB4 and CB5 are both approximately 1.8m in

depth and run parallel to one another.

5.3.53. The cooling water pipeline would need to be a minimum of 600mm beneath the

base of each of the above pipelines, so an estimated minimum depth of 2.9-3.2m

is required at these crossings (taking into account the pipeline depth and pipe). It

is intended that the new pipeline will be installed at approximately 4m depth at

these locations.


May 2014 Page 5-15

Bedding and Backfill

5.3.54. The pipelines will be laid on granular bedding material, covered in selected fill,

and then excavated backfill. The exact design/ structure of the bedding and

backfill will be determined by the current use (i.e. highway, sewers etc.) and soil

type. Backfilling will occur in reverse sequence of removal to help ensure layers

are maintained where possible.

5.3.55. Where possible and subject to soil quality tests, excess spoil that is not required

for backfilling the trench (because the space is filled by the pipeline) will be used

as part of the land raising on the Proposed Development Site. This should avoid

the need for offsite disposal of any excess material.

Leak Testing

5.3.56. There will then be a requirement to hydrostatically test the pipeline. The pipeline

will be filled with water via the Bristol WWTW and pressure tested for leaks.

5.3.57. A pressurised pump and mobile test cabin will be sited at safe proximity from the

pipeline. Test instrumentation and the pressurising pump will be connected up to

the test head. The pipeline will be brought up to the test pressure and then

maintained for an estimated 24 hours. On acceptance of the test the pressure will

be reduced in a safe and controlled manner down to the static head pressure for

dewatering.

Clean Up and Restoration

5.3.58. Following completion of testing, reinstatement of the construction corridor will be

undertaken by a specialist crew which will aim to return the ground to its original

condition. Residual construction debris, including all temporary fencing, will be

removed from all construction sites.

5.3.59. Topsoil will be replaced to return the depth over the working width to the original

levels. The reinstatement of cultivated or grassed areas will only be carried out

when weather and ground conditions are suitable.

5.3.60. Disturbed areas in natural habitat areas will be seeded with a mixture of native

plant species to facilitate re-vegetation. Hedgerows disturbed by construction

activity will be re-instated, but tree planting will not be undertaken along the

pipeline route within woodland areas. Due to the possible interference of roots

with the integrity of the pipeline, there are restrictions on tree species and

planting distances from the pipeline.

5.3.61. These aspects are discussed further in Chapter 16: Ecology and Chapter 17:

Landscape and Visual Assessment.


May 2014 Page 5-16

Electrical Connection

5.3.62. Another part of the Associated Infrastructure is the electrical connection between

the Proposed Development and Seabank Substation. It is envisaged that the

cabling would be above ground, on an aerial cable bridge rack, however the

option for HDD beneath the Seabank 1 & 2 infrastructure remains a possibility.

The following two sections outline both of these methods.

5.3.63. Where electrical connections are installed above ground, they will be placed in a

rack inside a waterproof casing to protect against water damage and is therefore

not vulnerable to flood risk.

Cable Racks

5.3.64. The aerial cable bridge racks will be approximately 600mm wide and a height of

up to 3m, with 1.2m wide supports every 5-10m. Cable bridges may be needed to

lift the cable rack over equipment within the Seabank 1 & 2 site, which may lead

to the height increasing at specific locations.

5.3.65. The supports will be installed with approximately 1m deep foundations with a

construction corridor of approximately 20m. Figure 5-4, Volume III of this PEI

Report illustrates a typical electrical cable rack.

Horizontal Directional Drilling (HDD)

5.3.66. If required, HDD would utilise a drilling technique to lay the cable underneath

Seabank 1 & 2 site with minimal disturbance. The normal course taken by the

drilling operation is described in the following:

1. Planning, preliminary survey

2. Selecting the drilling units and drilling tools

3. Pilot bore and detection

4. Backreaming(s) or upsizing bore(s); and

5. Pulling in the pipe.

5.3.67. Figure 5-5 (Volume III of this PEI Report) illustrates a typical example of HDD.

Construction Method Statement (CMS)

5.3.68. The Principal Contractor will be appointed by the developer to develop and

implement a Construction Method Statement (CMS) through which mitigation and

compliance with The Construction (Design and Management) Regulations 2007

(Ref. 5-1) will be achieved.


May 2014 Page 5-17

5.3.69. The CMS will outline the different procedures to be undertaken in order to

complete the various works. Individual trade contracts will incorporate

requirements for environmental control, based on good working practice, such as

careful programming, resource conservation, adhering to health and safety

regulations and quality procedures. In this way those involved with the

construction phase, including trade contractors and site management, will be

committed to adopting the agreed best practice and environmentally sound

methods.

5.3.70. The CMS will be prepared in consultation with SGC and BCC at least 28 days

prior to the commencement of on-site works.

5.3.71. The CMS will include the following items:

• The updated construction programme;

• A broad plan of the construction works, highlighting the various stages

and their context within the project, including a full schedule of materials

and manpower resources, as well as plant and equipment schedules;

• Detailed site layout arrangements (including requirements for temporary

works), plans for storage, accommodation, vehicular movements,

delivery and access;

• Prohibited or restricted operations (locations, hours, etc.);

• Details of operations that are likely to result in disturbance, with an

indication of the expected duration of each phase with key dates,

including a procedure for prior notification of SBC and BCC and relevant

statutory and non-statutory (including neighbours) parties so that local

arrangements can be agreed;

• Details of utilities diversion;

• Site working hours;

• A procedure to ensure communication is maintained with SBC and BCC

and the local community to provide information on any operations likely

to cause disturbance (e.g. through meetings and newsletters);

• Provisions for affected parties to register complaints and the procedures

for responding to complaints;

• Provisions for reporting to the Applicant and SBC and BCC;

• Details of access and egress and proposed routes for HGVs; and

• Details of construction traffic (including parking and access

requirements) and changes to access and temporary road or footpath

closure (if required).


May 2014 Page 5-18

5.3.72. The CMS will be produced following receipt of the DCO (for example, as part a

Requirement attached to the DCO) and will identify all the procedures to be

adhered to throughout construction.

5.3.73. Individual trade contracts will incorporate environmental control, health and safety

regulations, and current guidance. This will ensure that construction activities are

sustainable and that all contractors involved with the enabling, preparation and

construction stages are committed to agreed best practice and meet all relevant

environmental legislation including: Control of Pollution Act 1974 (COPA) (Ref. 5-

3), Environment Act 1995 (Ref. 5-4), Hazardous Waste Regulations 2005 (Ref. 5-

5), and the Duty of Care Regulations 1991) (Ref. 5-6). Records will be kept and

updated regularly ensuring that all waste transferred or disposed of has been

correctly processed with evidence of signed Waste Transfer Notes (WTNs) that

will be kept on-site for inspection whenever requested. Furthermore all enabling,

preparation and construction works will adhere to the CDM Regulations (2007)

(Ref. 5-1).

Construction Environmental Management Plan (CEMP)

5.3.74. The commitments made within the CMS and ES will be incorporated into a

CEMP, which will include roles and responsibilities, detail on control measures

and activities to be undertaken to minimise environmental effects, and monitoring

and record-keeping requirements. The CEMP will describe the specific mitigation

measures to be followed to reduce nuisance effects from:

• Use of land for temporary laydown areas, accommodation, etc. It is

currently anticipated that the land to the east of the scheme reserved for

CCS will be used for laydown areas during construction;

• Enabling, preparation and construction traffic (including parking and

access requirements);

• Changes to access and temporary road or footpath closure (if required);

• Noise and vibration;

• Utilities diversion;

• Dust generation;

• Soil removal; and

• Waste generation.

5.3.75. Typical mitigation measures included in the CEMP will include the following:

• Restricted working hours and a procedure for consenting exceptions;

• A Commissioning Plan; and


May 2014 Page 5-19

• A Risk Management Plan.

5.3.76. A commitment will be made to periodically review the CEMP and undertake

regular environmental audits of its implementation during the construction phase

of the Proposed Development and associated infrastructure.

5.3.77. A framework for the CEMP which will be developed following receipt of the DCO

is provided in Technical Appendix C, Volume II of this PE Report.

Waste

5.3.78. Small amounts of waste will be generated during the construction programme.

The main sources of waste within the construction process are anticipated to

include:

• Packaging – plastics, pallets, expanded foams etc;

• Waste materials generated from inaccurate ordering, poor usage, badly

stored materials, poor handling, spillage etc; and

• Liquid wastes, other than surface water run-off and foul drainage, such

as waste oils and chemicals.

5.3.79. Any waste will be carefully managed and cleared to prevent nuisances such as

litter, dust, odour and pests, and to maintain a “clean” working and site

environment, for the benefit of all parties.

5.3.80. Contaminants found within the excavated material will be evaluated through site-

specific chemical test data, including Waste Acceptance Criteria (WAC) and

disposed of in accordance with relevant legislation.

5.3.81. During the construction phase, requirements for the management of waste will be

communicated to all contractors and sub-contractors to ensure that waste is

managed in accordance with the waste hierarchy and relevant statutory controls.

These measures will be controlled through the CEMP in consultation with the

relevant authorities.

5.3.82. A Site Waste Management Plan will be produced for the Proposed Development

post consent and prior to commencement of site works.

5.4. Operation

5.4.1. The operation of the Proposed Development is discussed in Chapter 4: Project

Description.


May 2014 Page 5-20

5.5. Decommissioning

5.5.1. It is envisaged that the plant will have a design life of at least 30 years, although

the operational life may be extended. After this time on-going operation will be

reviewed and if it is not appropriate to continue operation the site will be

decommissioned.

5.5.2. At the end of its operating life, the plant and all equipment will be shutdown and

removed from the Proposed Development Site. Prior to removing the plant and

equipment, all residues and operating chemicals would be cleaned out from the

plant and disposed of in an appropriate manner.

5.5.3. The fuel storage areas will be sealed to contain any leaks or spillages. It is

therefore highly unlikely that the Proposed Development will create any new

areas of ground contamination. Once the plant and equipment have been

removed to ground level, it is expected that the hardstanding and sealed

concrete areas will be left in place. Any areas of the plant which are below

ground level will be backfilled to ground level to leave a levelled area.

5.5.4. The decommissioning and demolition of the Proposed Development would be

considered at the detailed design stage as required by the Construction Design

and Management (CDM) Regulations.

5.5.5. A Decommissioning Plan will be produced and agreed with the EA as part of the

environmental permitting process.

5.5.6. The following measures will be employed in the Design of Works to manage

(including elimination) SHE risks decommissioning stage. Particular attention will

be given to avoid use of deleterious materials and the contamination of ground

due to material/chemical storages and plant operations.

Avoidance of Deleterious Materials

5.5.7. The Prohibited Materials will not be allowed within the Works, including all

elements of Plant.

5.5.8. Where a material is recognised as posing a risk to the health of either or both

personnel and environment, however is not a Prohibited Material, it’s use in the

Works shall be subject to detailed risk assessment.

5.5.9. The following materials are prohibited and the Contractor will be instructed to

avoid their use within the Works;

• Asbestos or asbestos-containing materials;

• Naturally occurring aggregates for use in reinforced concrete which do

not comply with the relevant standards;


May 2014 Page 5-21

• Cast iron piping materials for any oil service;

• PCBs;

• CFC’s or other ozone depleting substances, except in applications where

their use is accepted and cannot be avoided, subject to Project Manager

acceptance;

• Carcinogenic materials;

• Materials known in the construction industry at the time of use to be

deleterious to health or the environment when used or incorporated in

such Work;

• Material which is known to or is reasonable believed to cause failures in

buildings;

• Material which is accepted as being or is believed to be deleterious via:

a. becoming deleterious when used in a particular situation or in

combination with another material(s);

b. becoming deleterious without a level of maintenance higher than that

expected in a plant of comparable type; and

c. being damaged by or causing damage to any structure in which it is

incorporated or affixed.

• Tropical hardwood which is not obtained from a source accredited in the

Good Wood Guide published by Friends of the Earth.

• Materials which are not in accordance with recommendations within a

booklet entitled “Good Practice in the Selection of Construction

Materials” written by Ove Arup & Partners and sponsored by the British

Property Federation & British Council for Offices, any Statutory

requirements, British Standards, Codes of Practice or good building

practice.”

Above the Ground Storages/silos for Chemical Storages

5.5.10. All chemicals including fuel for diesel generators will be stored in above the

ground silos. The silos will be required to comply with the relevant British

Standards and good industry practice. All Silos will be provided with the

containment measures as per HSE guidelines. All additional measures (other

than robust design), such as containment, emergency response, arrangements

for offsite transport and treatment/disposal, will be in place to avoid any ground

contamination form chemicals.


May 2014 Page 5-22

Segregation of Dirty/Clean Water

5.5.11. Run-off or spillages from designated 'dirty' areas and process water discharges

will be segregated from clean works area and surface water runoff and be

separately contained for disposal offsite via road tanker. Contaminated water

containment systems will accommodate all additional loading from fire water

systems. All contaminated water resulting from normal, abnormal or emergency

Plant conditions shall be contained and either reused in the plant or transported

off site for treatment or safe disposal.

5.6. References

Ref. 5-1 HMSO (2007); The Construction (Design and Management) Regulations

Ref. 5-2 DECC (2009) Carbon Capture Readiness (CCR) A guidance note for Section 36 Electricity Act 1989 consent applications

Ref. 5-3 HMSO (1974); Control of Pollution Act (amended 1989)

Ref. 5-4 HMSO (1995); The Environment Act

Ref. 5-5 HMSO (2005); Hazardous Waste (England and Wales) Regulations

Ref. 5-6 HMSO (1991);The Environmental Protection (Duty of Care) Regulations

Seabank 3 PEI Report – Chapter 6 Project Need and Alternatives

May 2014 Page 6-1

6. Project Need and Alternatives

6.1. The Need for the Proposed Development

6.1.1. The Energy White Paper ‘Meeting the Energy Challenge’, published in 2007 by

the Department for Trade and Industry, formed the basis of the Energy Act 2008

(Ref. 6-1) and sets out the Government’s plans for tackling climate change by

reducing carbon emissions whilst ensuring the availability of secure, clean,

affordable energy.

6.1.2. The White Paper and the Overarching NPS for Energy (EN-1) (Ref. 6-2) both

emphasise the importance of a diverse mix of energy generating technologies,

including renewables, nuclear and fossil fuels, to avoid over-dependence on a

single fuel type and thereby ensure security of supply.

6.1.3. Changes to the current mix of energy generating plant will occur as a large

number of existing oil, coal and nuclear power stations close over the next 10-15

years due to the requirements of the European Large Combustion Plant Directive

and/or as plants reach the end of their operational lives. Projections quoted in the

Energy NPS indicate 22 gigawatts (GW) of electricity generating capacity will

close over this period. This creates a significant need for new major energy

infrastructure.

6.1.4. The long lead-in for new nuclear power stations means that new fossil fuel and

renewable generating capacity will also need to be progressed to meet demand.

6.1.5. Renewable energy is important to achieve the UK’s targets for reductions in

carbon emissions but the Energy NPS also emphasises the on-going requirement

for fossil fuel power stations as they offer more flexibility in response to changes

in energy demand compared to many renewable energy technologies.

6.1.6. Gas-fired generation contributes to the objective of reducing carbon dioxide

(CO2) emissions, as generating electricity from natural gas is more efficient than

other fossil fuels such as coal, resulting in significantly lower CO2 emissions per

MW compared to alternative fossil fuel power stations.

6.1.7. The recent draft Electricity Market Reform (EMR) Delivery Plan by the DECC

(Ref. 6-3) also outlines a greater need for flexible capacity in gas-fired generation

to ensure supply can meet demand at all times. DECC indicates an expected

requirement for up to 23GW of peaking plant by 2030 to support the provision of

renewable power generation such as wind power.


May 2014 Page 6-2

6.2. Alternative Sites

6.2.1. The Applicant continuously considers potential sites for new power generation

development. In addition to the Proposed Development Site at Severnside, the

Applicant has considered a number of other sites in the UK for new gas fired

generating stations, several of which may lead to further DCO Applications.

6.2.2. A range of factors are considered in the selection and prioritisation of generating

station development sites, many of which relate to the commercial viability of

development. These include:

• Availability and suitability of sufficient land (not only for the power

generation technology but also for potential future CCS technology and

laydown areas for construction);

• Site sensitivity in terms of proximity to sensitive receptors such as

residential areas or designated ecological receptors;

• Site constraints including topography and ground conditions;

• Distance to electricity grid connection and gas supply connection and

location on the grid network, along with the cost of connection; and

• Accessibility.

6.2.3. The Proposed Development Site was selected primarily because of its proximity

to Seabank 1 & 2, which the Applicant already has a stake in, and the opportunity

this brings to utilise the existing gas, water and electricity infrastructure, avoiding

the need for significant additional infrastructure beyond that already planned. The

ability to avoid having to construct a cross country gas pipeline and overhead

electricity lines represents a significant cost saving, minimisation of

environmental effects, and a noticeable reduction in project risk.

6.2.4. The Proposed Development Site also has excellent road links with easy

accessibility to the M49, M5 and M4, as well as the potential access to a pool of

existing skilled labour at Seabank 1 & 2 for operations and maintenance should

the two sites ever be merged.

6.2.5. The Proposed Development Site is part of the Severnside area, which is

allocated by the SGC Core Strategy (Ref. 6-4) for employment uses based on

extensive opportunities for storage and distribution development. Its industrial

setting also means there are relatively few sensitive receptors in the immediate

surrounds, with the nearest residential dwellings comprising a few scattered farm

dwellings approximately 1.1km southeast of the Proposed Development Site.

6.2.6. It is important to note the Applicant has already secured a 1,200MW grid

connection agreement with National Grid from 2019 for the Proposed


May 2014 Page 6-3

Development and is currently negotiating an extension to this, which would

increase it to 1,400MWe.

6.2.7. Further justification for the need for the Proposed Development and choice of site

is presented in the Planning Statement, which has been submitted as a

supporting document to the DCO Application.

Do Nothing Alternative

6.2.8. It is considered that the ‘Do Nothing’ scenario is not appropriate given the

established need for new energy generation in the UK (outlined in Overarching

NPS for Energy EN-1, Ref. 6-2). Furthermore the allocation of the Severnside

area for distribution and other extensive employment uses, including energy

generation, in the SGC Core Strategy underlines the importance of providing new

generating capacity at the Proposed Development Site. A key disadvantage of

the ‘Do Nothing’ scenario would be the lack of additional investment in the local

economy and failure to contribute to the energy need outlined above.

6.3. Consideration of Alternative Locations within the Selected Site

6.3.1. There are relatively few options available in relation to the specific location of

plant given the constraining size and shape of the Proposed Development Site.

The preferred location of the Generating Station Site, adopted for the concept

design to date and as assessed in this PEI Report, is in the western part of the

Proposed Development Site, adjacent to the Seabank 1 & 2 site.

6.3.2. The principal reason for locating the Generating Station Site and its components

adjacent to Seabank 1 & 2 is that it enables the electrical cables and cooling

water pipeline to be routed through the existing generating station, the option of

an access point connecting the two stations, and for the two sites to be operated

as a common station should Seabank Power Ltd (current operators of Seabank 1

& 2) choose to invest in the Proposed Development at any point in the future.

There is also no immediate requirement to divert overhead lines, which are

present on the CCR Site.

6.3.3. In terms of plant layout, as a Main Contractor has not yet been selected for the

construction of the Proposed Development, the concept design has been

developed to allow for a range of technologies and plant layouts. The objective of

this is to ensure a number of potential contractors could tender for and ultimately

construct the Proposed Development utilising their preferred technology and

plant layout. Maximum and minimum parameters have therefore been defined

(see Chapter 4: Project Description) and assessed within this PEI Report utilising

a ‘Rochdale Envelope’ approach (see Chapter 2: The DCO and EIA Process).

Information received during the preliminary design work and from other CCGT


May 2014 Page 6-4

plants constructed elsewhere in the UK or overseas, has been utilised to

establish the maximum and minimum parameters required for each element of

the plant.

6.3.4. The development parcels have been ‘fixed’ in terms of location for the purposes

of this PEI Report, with the buildings retaining more ‘flexibility’ in their layout

within the ‘Rochdale Envelope’.

6.4. Consideration of Alternative Layouts within the Selected Site

6.4.1. Prior to publishing the Scoping Report the Applicant investigated various options

in terms of the design layout and installed capacity of the Proposed

Development. The feasibility and design options study considered the following

options for the Proposed Development Site:

• A 400MW CCGT generating station on a minimum plot area of 7ha;

• A 800-850MW CCGT generating station on a site of 14-18ha; and

• Up to a 1,400MW CCGT power station on an area of around 19ha (the

chosen scheme, albeit on a larger footprint to include peaking plant and

an area designated for CCS).

6.4.2. The 400MW and 800-850MW alternatives were abandoned in favour of the larger

electricity output achieved by the chosen scheme in order to maximise the

generating potential of the Proposed Development Site.

6.4.3. The subsequent layout of the chosen scheme was influenced by the dimensions

of the key elements of plant and equipment that need to be housed within the

main buildings and by the engineering requirements needed for the CCGT Plant

to operate in the most efficient manner.

6.4.4. The following considerations were taken into account during the layout design:

• Utilities and services corridor: The inclusion of a services corridor

along the southern boundary of the Proposed Development Site,

following the existing line of Feeder 14 gas pipeline, to accommodate

existing, relocated, and future pipelines, within a reserved area free from

buildings and structures. If CCS is ever to be implemented then the

services corridor would also provide a route for power plant

interconnecting ductwork.

• Cooling system: This is located at the western end of the Generating

Station Site, mimicking the general visual massing of Seabank 1 & 2 with

cooling water system in the west of the existing station. This is also

deemed the optimum site location when considering prevailing wind


May 2014 Page 6-5

direction (west to southwest) to prevent screening by the higher

structures onsite, thus it will aid the cooling effect in the cooling water

system.

• Switchyard: The 400kV switchyard has been located near to southwest

boundary, close to the exit point to Seabank 1 & 2, in line with the cable

route to the Seabank 400kV substation.

• Peaking Plant: The peaking plant units were originally located closer to

the main boilers and stacks, however preliminary air dispersion modelling

demonstrated that the stack heights and air quality impacts could be

reduced slightly by moving these units further east within the Generating

Station Site, geographically separating them from the HRSG building.

6.4.5. In addition to engineering requirements, environmental effects have been

considered throughout the design process. These include the orientation of the

power block buildings to screen the stacks, and keeping a distance from public

roads to reduce the visual impact. Space has also been incorporated for

landscaping, water attenuation ponds, and ecological habitat mitigation in the

latest design.

6.4.6. Figures 6-1 to 6-3 (Volume III of this PEI Report) illustrate some of the key

changes to the Proposed Development throughout the project evolution, based

on the single shaft layout:

• Figure 6-1 (Volume III of this PEI Report) illustrates the layout of the

Proposed Development for the initial concept produced in April 2012,

which comprised two 600MW CCGT units. It shows the turbine and

HRSG buildings at the westernmost end of the Site, with the cooling

water system to the east. No peaking plant is included at this stage of the

design.

• Figure 6-2 (Volume III of this PEI Report) illustrates an interim layout in

March 2013. Five options were considered at this stage; some options

had the cooling water system located west of the turbine and HRSG

buildings, whilst others retained the cooling water system to the east of

these buildings. They also tested different orientations for the turbine and

HRSG buildings. The option that is illustrated in Figure 6-2 (Volume III)

shows the cooling water system now located in the west of the Site and

incorporates peaking plant immediately east of the turbine and HRSG

buildings.

• Figure 6-3 (Volume III of this PEI Report) presents an amended layout in

August 2013. The cooling water system is still shown in the western side

of the Site, aligned slightly differently but still northwest to southeast. The

turbine and HRSG buildings have been expanded slightly to incorporate


May 2014 Page 6-6

the maximum design parameter from a range of potential Contractors

and achieve up to 1,400MW. The peaking plant has been moved away

from the turbine and HRSG buildings to the eastern part of the

Generating Station Site; preliminary air quality modelling showed that the

peaking plant stack heights would have had to be similar in height to the

main stacks if they were retained in their previous location.

• Figure 4-2 and Figure 4-3 (Volume III of this PEI Report) illustrate the

final layout utilised for this PEI Report. The cooling water systems have

been reoriented, so they are now aligned southwest to northeast. This

enabled the other main structures onsite to move west slightly away from

the narrowest part of the Site, which in turn allowed a new landscaping

area for trees and vegetation between the northern facades of these

buildings and the 8m easement along the Red Rhine. This also removed

the need for the retaining wall along this 8m easement shown on earlier

iterations, and provides some vegetation screening for views from users

of the Access Spine Road.

The peaking plant is now shown as enclosed within a building, for design

consistency with the other buildings onsite (although depending on the

technology selected there is the possibility that these may not require to

be enclosed, as discussed later in this chapter). They have also been

moved slightly, to avoid a clearance area beneath the 400kV OHL.

There is a new area of landscaping between the Generating Station Site

and the CCR Site, to breakup long distance views from the east, and

which is shown to include a rainfall runoff attenuation pond. And finally,

the proposed PROW, which previously dissected the Generation Station

Site and CCR Site, is now shown as being routed along the length of the

CCR Site, around the southern boundary of the Proposed Development

Site to the existing roundabout that currently lies immediately to the east

of the Site.

6.4.7. In order to ensure the CCR Site was of sufficient size, some preliminary layouts

show the CCS technology superimposed (although it was never intended that this

would form part of the DCO Application).

Stack and Building Heights

6.4.8. In order to allow for further project evolution and development, and to provide

sufficient flexibility in the final design, maximum dimensions are set out in

Chapter 4: Project Description. This approach enables the EIA to be undertaken

on the maximum or worst case basis, and provides the flexibility needed within

the DCO Application to enable a range of equipment supplier and Contractors to

be considered.


May 2014 Page 6-7

6.4.9. The stack height has been informed by air dispersion modelling, technical

feasibility studies and the informal consultation process, and has been fixed at

90m above the finished ground level for the purposes of this PEI Report (the

equivalent of 98.5m AOD assuming the finished ground level is built to its

maximum 8.5m AOD, as discussed in Chapter 5: Enabling Works and

Construction). This is a reduction of 10m from the EIA Scoping Report, which

suggested the main stacks would be up to 100m above the finished ground level.

6.5. Alternative Technologies

6.5.1. Throughout the design process consideration has been made to alternative

technologies, design options and plant layout. These decisions have, where

relevant and possible, been informed by environmental appraisal work and the

design has evolved through a continuous process of environmental assessment

and design development.

6.5.2. Aspects where options have been considered and these are now ‘fixed’ include

the method of cooling, which is discussed further below.

6.5.3. There are also a number of aspects of the design where options remain

available. Some of these aspects will have a final option determined at the time of

the application, though others are likely to retain options within the final DCO

Application. The selection of specific options, along with any project evolution of

the concept design, will be informed, where appropriate by the EIA work, on-

going discussions with potential bidders for the construction of the plant and the

feedback received through the consultation process.

Cooling Units

6.5.4. A cooling system is required to enable the Proposed Development to condense

the steam used in the power generation process once it has been exhausted

through the steam turbine, and before it is returned to the boiler for re-use.

6.5.5. At the outset of the scheme, three types of cooling methods were available:

• Direct wet-cooling technology: This consists of high efficiency water-

cooled condensers. It requires the abstraction of large quantities of water

from an accessible water source and the discharge of warmer water back

into the water source after it has been used for cooling. This method of

cooling requires the construction of an intake and outfall structure within

an appropriate controlled water body, such as a main river or estuary.

The main advantage of this cooling method is that it uses a colder

cooling medium (river water as opposed to air) and avoids the electrical

consumption of the fans used in air cooled condensers, thereby


May 2014 Page 6-8

improving the thermal efficiency of the fuel used. However, the

abstraction and discharge of water can only be undertaken in locations

and in a way that would not give rise to significant impacts on the water

body and the environment.

• Hybrid-cooling technology: This is essentially a combination of dry-

cooling and wet-cooling. Water must still be abstracted from a controlled

water source but by using a bank of low height cooling cells a smaller

volume of water needs to be abstracted than for direct water cooling, and

the temperature of the returned water is also lower. However, the use of

cooling cells can give rise to visible water plume emissions to air under

certain meteorological conditions and also results in a marginally lower

plant thermal efficiency than direct water cooling.

• Dry-cooling technology: This consists of a system of air-cooled

condenser fans situated in fan banks. The steam is condensed directly

by air in a heat exchanger (the air cooled condenser) and the

condensate is returned to the steam cycle in a closed loop. The air flow

is induced solely by mechanical draft from the fans. This cooling method

requires electrical energy to operate the fans, and therefore results in

reduced electrical output to the national transmission system. This

therefore increases fuel consumption and the emission of exhausts

gases for each megawatt of electricity produced, thereby reducing the

thermal efficiency of the system. However, the advantages of air cooled

condensers are that they require no cooling water abstraction, treatment

or discharge of cooling water and do not give rise to any visible plumes.

6.5.6. A feasibility assessment concluded that there are no fundamental reasons that

would technically prevent the adoption of direct sea water cooling for the

Proposed Development, and plant output would increase by approximately 1%. It

was however anticipated that there would be the potential for significant effects

on the environment, shipping and navigation, as well as substantial design and

construction challenges associated with extracting water from the Severn

Estuary, due to its high tidal range.

6.5.7. The full Best Available Techniques (BAT) justification will be presented with the

DCO Application. Preliminary discussions with the EA indicate that they concur

with the view that hybrid cooling water systems represent BAT for this installation,

due to a combination of technical and environmental challenges including the

effect on the ecologically sensitive marine environment that could arise from the

need to abstract and, in particular, discharge cooling water into the estuary.


May 2014 Page 6-9

Grid Connection

6.5.8. There are a number of options available for a Grid Connection which are

currently being evaluated, as outlined in Chapter 4: Project Description, and this

work is likely to be on-going when the final DCO Application is submitted. This

includes the option of underground cabling, which will be installed using HDD

beneath the Seabank 1 & 2 generating station, or an above ground cable rack

routed through the Seabank 1 & 2 station. The option of overhead lines was

dismissed for the Proposed Development.

CCGT Configuration

6.5.9. Another area where the design has evolved since the submission of the Scoping

Report and the informal consultation is regarding the configuration of the

generating station, as detailed below.

6.5.10. A number of alternative layouts have been considered for the Generating Station

Site, mainly in response to engineering requirements as outlined above. The two

remaining options include a multi-shaft and single-shaft CCGT as illustrated in

Figure 4-2 and Figure 4-3, Volume III of this PEI.

6.5.11. The single-shaft design provides more flexibility than if the gas and steam

turbines had their own generators, although the multi-shaft design enables two or

more gas turbines to operate in conjunction with a single steam turbine, which

can be more economical than having a separate steam turbine for each single

shaft unit.

6.5.12. At this stage, the configuration design will be left open to allow for flexibility in the

DCO Application. The single-shaft design is generally considered to be the ‘worst

case’ for the purposes of the technical assessments, as this layout has a slightly

larger footprint than the multi-shaft option.

Fast Response Generator / Peaking Plant

6.5.13. The Proposed Development includes the option of a peaking plant / fast

response generator up to 240MWe net, as set out in Chapter 4: Project

Description.

6.5.14. Different options were considered for the peaking plant including gas turbines

and reciprocating engines operating in open cycle mode as this offers the ability

to respond to changes in demand quicker than units operating in combined cycle.

6.5.15. Reciprocating engines generally have a smaller electrical output, typically up to

18MW capacity. Operating a number of these engines in concert provides greater

flexibility to respond to grid demand, however using larger gas turbines could


May 2014 Page 6-10

provide the same capability with fewer moving parts. The optimum configuration

has not yet been determined and may consist of a combination of these

technologies.

6.5.16. Preliminary air dispersion modelling demonstrated that the effect of having 13

reciprocating engines up to 240MWe was similar (within 1% of one another) to

two OCGTs up to 240MWe, provided the emissions associated with the former

are ducted together into two separate stacks (see Chapter 11: Air Quality). It was

decided therefore to retain the flexibility in the DCO Application for either

technology, with the footprint of the peaking plant units enlarged slightly so that it

can incorporate either option.

6.5.17. At this stage of the project it has not been determined whether or not the peaking

plant will be enclosed in a building. Reciprocating engines require an enclosure

and would therefore be covered by a building; this represents the maximum

design parameters because it requires a noticeably larger and taller structure to

house these machines. OCGTs are inherently enclosed and protected from the

weather and do not require an additional enclosure or building. Given that this

would substantially reduce the footprint and height of the peaking plant, it has not

been ruled out at this PEI stage.

6.5.18. The predicted effect associated with the atmospheric emissions is presented in

Chapter 11: Air Quality of this PEI Report.

Solar PV

6.5.19. Solar PV does not form part of the Proposed Development, however it was

considered as a means to supplement the energy requirements for the DCO Site

activities.

6.5.20. Roof mounted solar panels on the buildings within the Proposed Development

were discounted due to economic reasons; greater carbon savings can be

achieved by diverting the money on improving plant efficiency rather than

installing solar PV. This would negate the purpose of installing solar PV on the

site.

6.5.21. Ground based solar PV is still being investigated for the CCR Site, but does not

form part of the Proposed Development. The Applicant is committed to exploring

opportunities for this technology with local solar PV installation companies, which

if successful would be subject to a separate consenting process with SGC. The

CCR Site offers numerous benefits for solar generating facilities, such as the

existing electrical infrastructure being in place.

6.5.22. Any development on the CCR Site would need to avoid enhancing the ecological

value of this land (in accordance with NPS for Energy EN-1) (Ref. 6-2) to allow


May 2014 Page 6-11

the CCR Site to be made available should the Proposed Development be

required to install carbon capture technology. Carbon Capture would require a

separate DCO Application however, and therefore an investor would have

sufficient notice to decommission any development and vacate this land.

6.6. Associated Infrastructure

6.6.1. The scoping report (Ref. 6-5) presented a large indicative study corridor for a new

pipeline to supply cooling water and the electrical connection to Seabank

Substation. This corridor was approximately 1km wide, stretching from the M49 in

the east to Chittening Road.

6.6.2. Through the design process, identification of sensitive locations, and consultation

with BCC, it was decided that the route of the new cooling water pipeline should

follow the route of the existing two pipelines that currently supply/return cooling

water to Seabank 1 & 2. Most importantly, this would avoid sensitive ecological

receptors, namely a SNIC to the east of the cooling water pipeline.

6.6.3. The electrical connection corridor was also necessarily broad at the Scoping

stage, but is now restricted wholly within the Seabank 1 & 2 site, therefore

minimising any environmental impacts to undeveloped land.

6.7. Conclusions

6.7.1. Through analysis of site context, the Applicant’s development brief and

environmental considerations, a number of alternative designs have been

considered. The design was an iterative process whereby analysis of alternatives

was interpreted and proposals were made in order to address the concerns of

consultees and mitigate potentially adverse effects. Whilst the site strategy has

remained in line with the development brief, the detailed design has evolved

throughout the design and consultation process.

6.7.2. This process ultimately led to the present use, scale and form of the Proposed

Development, which is described further in Chapter 4: Project Description.

6.8. References

Ref. 6-1 HMSO (2008); Energy Act

Ref. 6-2 DECC (2011) Overarching NPS for Energy (EN-1)

Ref. 6-3 DECC (2013) Electricity Market Reform (EMR) Draft Delivery Plan

Ref. 6-4 South Gloucestershire Council (2013) Core Strategy

Ref. 6-5 URS (2012) Seabank 3 Scoping Report

Seabank 3

PEI Report –– Chapter 7 Assessment Methodology

May 2014 Page 7-1

7. Assessment Methodology

7.1. Introduction

7.1.1. This chapter of the PEI Report sets out the overall approach to the preparation of

the EIA and in particular the statutory requirements as outlined in the EIA

Regulations.

7.2. EIA Methodology

7.2.1. The EIA process as reported in this PEI Report has been prepared taking into

account or having had regard to:

• Consultation with statutory and non-statutory consultees to understand

the environmental and socio-economic issues concerning the

development of the DCO Site, in particular any development constraints

and opportunities;

• EIA scoping to agree and determine the subject matter of the EIA and to

identify potentially significant issues;

• Local, regional and national planning policies, guidelines and legislation

relevant to the EIA;

• Establishment and definition of the baseline conditions;

• Effects significance criteria, using published criteria where available;

• Identification of sensitive receptors;

• Design review and assessment of alternatives;

• Review of secondary information, previous environmental studies, and

publicly-available information and databases;

• Expert opinion;

• Physical surveys and monitoring;

• Desk-top studies;

• Monitoring and modelling (for example of the noise, air quality and visual

environments); and

• Reference to current best practice and guidance in relation to the

sustainability of the Proposed Development and associated

infrastructure.

Seabank 3


May 2014 Page 7-2

Baseline Conditions

7.2.2. In order to assess the potential effect of the Proposed Development and

associated infrastructure, it is necessary to determine the baseline conditions.

The baseline conditions are typically the current environmental and socio-

economic conditions of the DCO Site (at the time of writing the PEI Report). In

the context of the EIA for the Proposed Development Site, the existing baseline

scenario consists mainly of open grassland, crossed by a number of rhines

(drainage channels), including the Red Rhine.

7.2.3. Baseline conditions have been determined using the results of onsite surveys

and investigations or desk based data searches, or a combination of these, as

appropriate.

7.2.4. The technical chapters of this PEI Report (Chapters 9 to 19) describe as

necessary their spatial scope including their rationale for determining the specific

area within which the assessment is focussed. The study areas are a function of

the nature of the impacts and the locations of potentially affected environmental

resources or receptors.

7.2.5. The approach to assessment has been to assess the environmental impacts of

the Proposed Development at key stages in its construction and operation, and,

where possible, the decommissioning phase.

7.2.6. The 'current baseline year' is taken as 2013 (pre 01 December 2013) since this is

the period in which the baseline work for the PEI Report was undertaken.

7.2.7. The Proposed Development Site has undergone noticeable change since this

date, due to being used from mid-December 2013 by SITA for access to the

Severnside Energy Recovery Centre (which is currently under construction on

land immediately west of the Proposed Development Site) and the construction of

the Spine Access Road and new channel for the Red Rhine along the northern

boundary of the Proposed Development Site on behalf of Severnside Distribution

Land Ltd. A brief description of these other developments is presented later in

this chapter.

7.2.8. The baseline conditions onsite are therefore dynamic and will be changing week-

to-week from mid-December 2013 to the expected date of submission of this PEI

Report.

7.2.9. The description of baseline conditions will be updated for the final ES, to reflect

the state of the Proposed Development Site at the point of submitting the

Application, or at an agreed point in time shortly beforehand. Any changes to the

predicted effects and mitigation measures due to the change in baseline

conditions would also be captured in the final ES.

Seabank 3


May 2014 Page 7-3

7.2.10. For the purpose of this PEI Report, a ‘future baseline’ scenario has been

assumed, which takes account of the fact that the Severnside Energy Recovery

Centre, a new Red Rhine channel, and the Spine Access Road will be built by the

time enabling works start for the Proposed Development; all three of these

developments are currently under construction.

Significance Criteria

7.2.11. The significance of effects is evaluated with reference to definitive standards,

accepted criteria, and legislation where available. Where it has not been possible

to quantify effects, qualitative assessments have been carried out, based on

expert knowledge and professional judgment. Where uncertainty exists, this has

been noted in the relevant assessment chapter.

7.2.12. The significance criteria generally lead to a common outcome of classifying the

significance of effects as major, moderate, minor or negligible. Effects are also

described according to whether they are considered to be adverse, neutral or

beneficial. Methodologies and criteria definitions necessarily differ between the

different technical studies, but where possible the same language is used, such

that the significance of the residual effects can be compared.

7.2.13. Specific significance criteria for each technical discipline have been developed,

giving due regard to the following:

• Extent and magnitude of the effect;

• Duration of the effect (whether short, medium or long-term);

• Nature of the effect (whether direct or indirect, reversible or irreversible);

• Whether the effect occurs in isolation, is cumulative or interactive;

• Performance against any relevant environmental quality standards;

• Sensitivity of the receptor; and

• Compatibility with environmental policies.

7.2.14. Each of the technical chapters provides details of the significance criteria used for

quantifying residual effects, including data sources and justifications.

7.2.15. In order to provide a consistent approach across the different technical disciplines

addressed within the PEI Report, the following terminology has been used

throughout the PEI Report to define residual effects (i.e. effects post the

application of mitigation measures):

• Adverse - Detrimental or negative effects to an environmental/socio-

economic resource or receptor; or

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• Negligible - Imperceptible effects to an environmental/socio-economic

resource or receptor; or

• Beneficial - Advantageous or positive effect to an environmental /socio-

economic resource or receptor.

7.2.16. Where adverse or beneficial effects have been identified these have been

assessed against the following scale:

• Negligible

• Minor;

• Moderate; and

• Major.

7.2.17. For avoidance of doubt, moderate and major residual effects are considered

‘significant’ in terms of the EIA Regulations (Ref. 7-1). Negligible and minor

effects are not significant.

7.2.18. In the context of the Proposed Development, short to medium-term effects are

generally considered to be those associated with the construction phase; long-

term effects are those associated with the completed and operational Proposed

Development and associated infrastructure. Local effects are defined as those

affecting the DCO Site and neighbouring receptors, while effects upon receptors

in SGC and BCC (or similar scale, even if they occur across other local authority

boundaries) are considered to be at a district or regional level. Effects on different

parts of the country, or England as a whole, are considered national. Beneficial

and adverse, short and long-term (temporary and permanent), direct and indirect,

and cumulative effects have also been considered within the EIA. Where there

are no predicted effects, this is stated in the technical assessments.

7.2.19. The relationship between the sensitivity of receptors and the likely magnitude of

change caused by the effect allows the relative significance of predicted effects

on the landscape to be defined. Table 7-1 below provides a typical matrix used

by several technical assessments to describe this relationship, and so allows a

relative level of significance of any predicted effect to be categorised.

Table 7-1: Matrix Defining the Significance of Effects

Magnitude of Change

Sensitivity of Receptor

High Medium Low Very Low

High Major Major Moderate Minor

Medium Major Moderate Minor Negligible

Low Moderate Minor Negligible Negligible

Very Low Minor Negligible Negligible Negligible

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7.2.20. Where there are deviations away from the matrix as presented above, this will be

highlighted within the chapter and the reason for the variation explained. For

example, Chapter 9: Land Use, Recreation and Socio-economics does not

categorise the magnitude of change or sensitivity of a receptor, and therefore

avoids using the above matrix to determine significance of effects. This can be

justified since aspects such as the labour market and public rights of way do not

lend themselves naturally to being categorised in the manner described above.

7.2.21. Each technical chapter sets out specific measures which have been incorporated

into the design of the Proposed Development and associated infrastructure to

avoid or minimise impacts. Any mitigation measures that are to be implemented

that are considered to be standard or common throughout the construction or

power industries are also described. These include compliance with Best Practice

guidance documents (e.g. EA pollution prevention guidelines). The initial impact

assessment is undertaken giving consideration to measures already being

implemented or to be implemented as standard; for example preliminary

atmospheric dispersion modelling has determined the stack heights assessed in

this PEI Report.

7.2.22. Due to the current stage of the design process it has not been possible to specify

all measures adopted to date within this PEI Report, however any assumptions

made regarding avoidance or mitigation measures within the preliminary

assessment are summarised within the chapters.

7.2.23. Once the likely effects have been identified and quantified, consideration is given

to any additional mitigation (over and above anything identified within design

process) that may be required to mitigate any significant effects identified.

7.2.24. Finally, the residual effects once mitigation has been implemented are assessed

and presented. These residual effects are also summarised in Chapter 21:

Residual Effects.

7.3. Structure of this PEI Report

7.3.1. As discussed within Chapter 1: Introduction, this PEI Report consists of three

volumes and a Non-Technical Summary.

7.3.2. Volume I (this volume) forms the main body of the PEI Report, detailing the

results of environmental investigations, potential effects arising, and the proposed

mitigation measures. The PEI Report also identifies opportunities for social and

economic benefit and environmental enhancement. It is divided into a number of

background and technical chapters supported with figures and tabular

information.

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May 2014 Page 7-6

7.3.3. Each topic has been assigned a separate technical chapter in the PEI Report as

follows:

• Land Use, Recreation and Socio-Economics;

• Traffic and Transport;

• Air Quality;

• Noise and Vibration;

• Ground Conditions;

• Water Resources and Flood Risk;

• Cultural Heritage and Archaeology;

• Ecology;

• Landscape and Visual Impact Assessment;

• Sustainability; and

• Health.

7.3.4. In addition to the above, the following chapters are provided as part of this PEI

Report:

• Introduction;

• The DCO and EIA Process

• The Site and Its Surroundings;

• Project Description;

• Enabling Works and Construction;

• Project Need and Alternatives;

• Assessment Methodology;

• Planning Policy Context;

• Cumulative Effects

• Residual Effects; and

• Glossary of Terms.

7.3.5. Volume II Technical Appendices of this PEI Report comprises background data,

technical reports, tables, figures and surveys. The appendices provided are as

follows:

• Appendix A: EIA Scoping and Scoping Opinions;

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• Appendix B: Electronic Interference Screening Assessment;

• Appendix C: Construction Environmental Management Plan;

• Appendix D: Planning Policy;

• Appendix E: Traffic and Transport;

• Appendix F: Air Quality

• Appendix G: Noise and Vibration

• Appendix H: Archaeology

• Appendix I: Ground Conditions

• Appendix J: Flood Risk, Hydrology and Water Resources

• Appendix K: Ecology

• Appendix L: Landscape and Visual Assessment

• Appendix M: Sustainability

• Appendix N: CHP Assessment

7.3.6. Volume III of this PEI Report presents the figures referred to in this report

(Volume I).

7.3.7. The PEI Report Non-Technical Summary is presented as a separate document,

providing a concise description of Volumes I to III, including the Proposed

Development and associated infrastructure, alternatives considered, potential

environmental effects, and mitigation measures. The Non-Technical Summary is

designed to give information on the DCO Application to a wide and non-technical

audience and to assist interested parties with their familiarisation of the Proposed

Development and associated infrastructure.

7.4. Structure of PEI Report Chapters

7.4.1. The technical chapters of this PEI Report follow a common structure and format.

Within each chapter the assessment has been structured in the following way:

Introduction

7.4.2. This section describes the format of the assessment presented within the chapter

and identifies the author, as well as outlining the consultation responses relevant

to the assessment received to date. It also includes a brief summary of legislation

and applicable policies and plans relevant to the Proposed Development.

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Assessment Methodology and Significance Criteria

7.4.3. This section describes the approach taken to the assessment including the

surveys/studies and research undertaken to determine the baseline conditions

and the procedure followed to assess the effects of the Proposed Development

and associated infrastructure. Topic-specific effect significance criteria and the

standards/guidance from which they are derived are explained and definitions of

minor, moderate, and major (adverse or beneficial) and negligible effects is

provided.

Baseline Conditions

7.4.4. As discussed earlier in this chapter, the environmental conditions that currently

exist on the DCO Site (the ‘baseline conditions’) are considered and presented

within this section of each technical chapter. For all issues, the EIA baseline has

been taken as the conditions on-site prior to 01 December 2013, unless

otherwise stated. Further reference is made to aspects of the baseline that may

be sensitive to the Proposed Development and associated infrastructure, i.e.

sensitive receptors such as residential dwellings.

7.4.5. Where relevant the technical chapters present and discuss a Future Baseline

scenario. A number of other schemes are currently being progressed by third

parties onsite and adjacent to the Proposed Development Site, which will change

the baseline conditions between the submission of this PEI Report and the ES.

This includes the development of the Severnside Energy Recovery Centre to the

west of the Proposed Development Site which will use the Proposed

Development Site for the creation of a new spine road along the northern

perimeter of the Proposed Development Site, and the excavation of a new

drainage channel for the Red Rhine within the northern perimeter of the

Proposed Development Site. These projects are discussed in more detail in the

subsection ‘Cumulative Effects’.

Development Design and Impact Avoidance

7.4.6. The EIA and design process is iterative and a number of mitigation measures

have been embedded into the Proposed Development as a result of preliminary

studies or to minimise adverse effects and maximise opportunities for beneficial

effects. This section is intended to outline the design measures prior to

presenting the assessment of effects. For example, the Proposed Development

incorporates two 90m stacks for the CCGT units and two 45m stacks for the

peaking plant; these stack heights were determined through extensive

atmospheric dispersion modelling tests to achieve an acceptable effect on air

quality; this mitigation is incorporated into the description of the Proposed

Development presented in Chapter 4: Project Description.

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Potential Effects and Mitigation Measures

7.4.7. This section identifies the potential effects resulting from the Proposed

Development and associated infrastructure and considers effects during

construction and once it is completed and operational. The effects of the

Proposed Development and associated infrastructure are defined against the

existing baseline. This section also describes the mitigation measures that the

Applicant will implement to reduce adverse effects and enhance beneficial effects

relevant to the Proposed Development and associated infrastructure.

7.4.8. The various technical chapters also consider the inter-relationship of effects in

this section, also sometimes referred to as in-combination effects (effects caused

by two or more impacts of the Proposed Development in combination). In

particular these are considered in the chapters that focus on specific receptors,

such as Chapter 16: Ecology, which considers the in-combination effects of

noise, air quality, habitat loss, disturbance etc. on ecological receptors, or

Chapter 11: Air Quality for example, which may consider the effect of the stack

emissions and additional road traffic emissions together at a particular receptor.

Residual Effects

7.4.9. This section assigns significance to those effects of the Proposed Development

and associated infrastructure which remain once mitigation measures are in

place for both the construction and operational phases. It is only those residual

effects that are ‘moderate’ or ‘major’ in this PEI Report which are considered

‘significant’ in terms of the EIA Regulations.

Cumulative Effects

7.4.10. As required by the EIA Regulations (Ref. 7-1), it is important to consider the

potential for cumulative effects of the Proposed Development and associated

infrastructure when considered along with other developments planned or

consented in the vicinity of the DCO Site. Existing schemes such as Seabank 1 &

2 form part of the baseline conditions described above.

7.4.11. The assessment of cumulative effects has been based upon the information

available at the time of writing and currently available assessment techniques.

7.4.12. The schemes included within the cumulative effect assessment have been

identified in consultation with SGC and BCC, and comprise those within a 6km

radius of the Proposed Development Site and which are more than 1ha in size

(and therefore of sufficient proximity and scale to potentially lead to cumulative

effects).

7.4.13. A list of development schemes consented for planning, under construction or at

pre-planning submission stage that have been included within the cumulative

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May 2014 Page 7-10

effect assessment is provided below. The locations of these cumulative schemes

are illustrated in Figure 7-1 (Volume III of this PEI Report).

1. Avon Power Station (Scottish Power) Pre-application. A proposed

CCGT power station on the former Terra Nitrogen and ICI site in

Severnside. This has not yet reached the EIA Scoping stage and

therefore information on this scheme is sparse, limited to a preliminary

application site boundary and suggestions that it would comprise

900MWe of CCGT.

2. Severnside Energy Recovery Centre (SITA) – PT09/5982/FMW:

Granted. Development of an Energy Recovery Centre (called SERC).

The application was granted on appeal in 2011. Construction works have

begun onsite and SITA will use the Proposed Development Site for

laydown, access, and other activities associated with the construction

works.

3. Bottom Ash Facility (SITA) – APP/P0119/A/10/2140199: Granted.

Bottom Ash Facility and associated Railhead which will serve the

consented Severnside Energy Recovery Centre (SERC).

4. Spine Access Road (Severnside Distribution Land Ltd) –

PT12/1207/MW: Granted. A road linking the adjacent SERC with the

A403 (via a new 3-arm roundabout to be constructed on the A403).

Permission was granted by SGC for the access road under reference

PT09/5982/FMW, and a further application was granted planning

permission for the re-alignment of the original planned and approved

road under reference. Severnside Distribution Land Ltd intends to extend

this new Spine Access Road around the northern perimeter of the

Proposed Development Site, under the extant 1957/58 consent (which is

discussed further in bullet point 15). Construction works started in winter

2013/14.

5. Anaerobic Digestion Facility (New Earth Solution) – PT12/1015/MW:

Granted. Change of use of agricultural land to anaerobic digestion

facility including weighbridges, reception building, biofilter, digestion and

storage tanks and associated plant and infrastructure. This is currently

under construction and due to open in 2014.

6. Resource Recovery Centre (VIRIDOR) – 09/04470/F: Granted. The

construction and operation of a Resource Recovery Centre including a

materials recycling facility, associated office, visitor centre and energy

from waste and bottom ash facility, with new access road and

weighbridge facilities, associated landscaping and surface water

attenuation features.

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7. Deep-sea Container Terminal (Bristol Port Company) - 08/03387/K:

Granted. Construction of a deep-sea container terminal on the site of a

former oil terminal at Avonmouth to accommodate the existing large

container ships and future generations of Ultra Large Container Ships

(ULCS).

8. Biomass Plant (Helius Energy) – 09/00506/K: Deemed Planning

Permission Granted - Construction of Biomass fuel store and biomass

fired electricity generating plant, capable of generating approximately

100MW of electricity.

9. Bristol Resource Recovery Centre (Cyclamax) Plot M2, Merebank

Estate, Kingsweston Lane - 11/01773/F: Granted. Proposed Bristol

Resource Recovery Centre to consist of: a 100,000 tonnes per annum

batch oxidation gasification facility; a 80,000 tonnes per annum materials

recycling facility to process source segregated recyclable materials; an

end of life plastics to fuel conversion facility; a vehicle depot for waste

collection vehicles; and a temporary refuse derived fuel production facility

to be located within the proposed gasification building.

10. W4B, Former Columbian Chemicals (Sevalco), Severn Road -

09/03235/F: Granted on appeal. Redevelopment of part of existing

industrial site for a Bio-fuel energy plant together with ancillary access

roads, parking facilities and landscaping.

11. Unit and Service Centre (Asda), Former Rhodia Works, St. Andrews

Road - 12/03149/F: Granted. Redevelopment of the former Rhodia

chemical works to provide a chilled distribution unit (Use Class B8) and

an ancillary service centre (Use Class B2).

12. Rockingham Park (Terramond Ltd), – 11/05157/P: Granted. Outline

planning application for industrial redevelopment, comprising B1(b),

B1(c) and B8 uses.

13. Biomass Renewable Energy Plant (E.ON), Portbury Docks –

09/00506/K: Granted. An application to build a biomass-fired renewable

energy plant as a means of increasing electricity generation derived from

non-fossil fuels. The proposed plant would be located at the Royal

Portbury Dock, within the Port of Bristol and would be developed on a

plot of land approximately 5ha in size, leased to E.ON by The Bristol Port

Company.

14. Hinkley Point C Connection (National Grid) – DCO Application, not

yet submitted. A new 400kV connection between Bridgwater, Somerset

and Seabank Substation, north of Avonmouth. It is proposed to extend

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May 2014 Page 7-12

the existing Seabank electricity substation compound and substation

building to accommodate additional electrical plant and equipment. It

includes an OHL across the River Avon to the west of the existing 132kV

OHL and then follows the edge of Avonmouth village (travelling through

the Avonmouth Docks complex) before heading through the centre of the

industrial area and connecting into Seabank substation. An off spur of

the assessment corridor crosses the DCO Site, as illustrated in Figure 7-

1 (Volume III of this PEI Report), although it is understood this is required

for access near Poplar Roundabout rather than any works to OHLs.

15. The 1957 Consent – SG 4244: Granted. Planning permission was

granted on 27 November 1957 for a variety of uses on approximately

1,060ha of land, with an additional 10ha added by a 1958 consent, which

remains extant for future development. Approximately 405ha is approved

for industrial use – for the construction and operation of factories for the

production of chemical and allied products (including non-ferrous metals)

and for the development of offices, warehouses, canteens, clubs,

hostels, training establishments, sports pavilions and playing fields etc.

This includes the Proposed Development Site (but not the Other DCO

Land). A peripheral 220ha, mainly in the eastern portion of the consented

area, allows for the development of offices, warehouses, canteens,

clubs, hostels, training establishments, sports pavilions and playing fields

etc. A further 445ha of land extending from the coastline into the Severn

Estuary was originally approved for the construction and operation of any

buildings structures or engineering works expedient to the construction

and operation of the factories, though this was later rescinded through a

Section 106 agreement with ICI accompanying the granting of planning

permission for the development of the first phase of the Western

Approaches Business Park (P94/400/8). This agreement included the

setting aside of 38ha of land for ecology enhancements and the creation

of a number of green corridors within the 1957-58 consented land.

Developments being built under this extant planning permission include,

but are not limited to, the following:

• Spine Access Road. Severnside Distribution Land Ltd intends to extend

the new spine access road mentioned in point 4 above around the

northern perimeter of the Proposed Development Site. Enabling work

has begun on this project.

• Diversion of the Red Rhine. Severnside Distribution Land Ltd also

intends to create a new drainage channel or rhine along the northern

boundary of the Proposed Development Site under this extant consent

and with permission from the Lower Severn Internal Drainage Board. The

Red Rhine will be diverted into this new channel as part of the enabling

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May 2014 Page 7-13

works for the Proposed Development. The creation of this new channel

commenced in winter 2013/14.

• Central Park. A 240ha (600 acre) warehouse and distribution park

development, which is strategically located within the region and

designed to be the South West’s largest distribution park, capable of

accommodating units of over 850,000 square foot (sq ft). The land for

Central Park is currently being raised to protect against flood risk.

7.4.14. The need for offsite gas enforcement or cross-country pipelines has been

discounted and is not considered further in this PEI Report. National Grid’s

Strategic Options Report (November 2013) identified ten options to meet the

need case. It concluded that the optimal solution was to modify a compressor

station in Wiltshire, most likely the Lockerley and Aylesbury Compression and

Flow stations. This is currently considered the best technical solution, least cost

and most environmentally considerate option; it also requires no additional

landtake. These upgrade works would be within existing stations and therefore

not likely to give rise to cumulative effects, especially as works will be within the

existing development boundary and are located over 100km from the Proposed

Development Site. The report concluded that there should be no need for any

new cross country gas pipelines in response to the Proposed Development. The

upgrade works have therefore been scoped out of the cumulative effect

assessment.

7.4.15. The CCS has not been included as a cumulative scheme. As discussed in

Chapter 4: Project Description, an area has been reserved for the potential future

siting of carbon capture and compression equipment, should it be required at a

future date in order to meet the requirements set out in the EU CCS Directive for

Geological Storage of Carbon Dioxide and to demonstrate that the Proposed

Development is CCR. The actual design and consenting of CCS technology and

infrastructure does not form part of this DCO Application, as it is not currently

required to be installed at the Site (nor does the technology actually exist at the

present time). Any CCS infrastructure would need to be consented separately at

the time it is required in the future. However, in accordance with DECC CCR

Guidance requirements, the CCR Site is included within the Proposed

Development Site boundary and the baseline conditions are described to enable

an assessment of the use of this part of the Site for construction compound,

parking and laydown, as described in Chapter 5: Enabling Works and

Construction.

7.4.16. Details of cumulative effects are provided in each of the technical chapters of the

PEI Report. A summary of the effects is provided in Chapter 20: Cumulative

Effects of this PEI Report.

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Impacts and Effects yet to be Determined

7.4.17. This section of the technical chapters provides a brief description of any

information not yet provided in the PEI Report which is intended to be included in

the final ES. This includes any survey data not yet collected and any impacts or

effects yet to be assessed.

7.4.18. Where there are no impacts and effects yet to be determined, this is noted. It is

recognised however, that the scheme design may be subject to change prior to

submission of the final DCO Application, following receipt of comments on this

PEI Report. Any changes that lead to differing or new impacts and effects will be

highlighted within the final ES, along with the reasons for the change.

7.5. Assumptions and Limitations

7.5.1. A number of general assumptions have been made during the EIA, which are set

out below. Assumptions specific to certain environmental aspects are discussed

in the relevant PEI Report chapters:

• Information provided by third parties, including publicly available

information and databases is correct at the time of publication;

• The construction programme associated with the Proposed Development

and associated infrastructure is indicative at this stage;

• Baseline conditions are accurate at the time of the physical surveys,

which were undertaken prior to 01 December 2013, but, due to the

dynamic nature of the environment, conditions will change prior to or

during the construction phase and on completion and operation of the

DCO Site. In particular, at the time of writing SITA and Severnside

Distribution Land Ltd have begun works on the SERC, Red Rhine

diversion and new Spine Access Road, which are all expected to

substantially change the baseline conditions within the Proposed

Development Site;

• Further intrusive on site work may be required in respect of ground

conditions, geotechnical and sub-surface archaeological remains

following receipt of planning permission so as to finalise substructure

construction methods; and

• The assessment of cumulative effects has been reliant on the availability

of information relating to all of the identified cumulative schemes

(whether submitted for planning, consented or under construction).

7.6. References

Ref. 7-1 HMSO (2009); Infrastructure Planning (Environmental Impact Assessment) Regulations

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PEI Report – Chapter 8 Planning Policy Context

8. Planning Policy Context

8.1. Introduction

8.1.1. This chapter outlines the overarching planning policy context for the Proposed Development, providing an overview of the relevant planning and energy policy framework which are material to the DCO Application.

8.1.2. This includes the relevant requirements of the National Policy Statements (NPSs), in accordance with which the National Infrastructure Directorate of the Planning Inspectorate is required to examine, and the Secretary of State (SoS) for Energy and Climate Change is required to determine, the DCO Application.

8.1.3. A more detailed review of legislative and policy matters will be provided in a Planning Statement that will form part of the DCO Application. A summary of the specific national and local planning polices relevant to each technical chapter is provided within Appendix D, Volume II of this PEI Report, along with any legislative requirements that need to be taken into account by the Proposed Development.

8.2. The Planning Act and National Policy Statements for Energy

8.2.1. The Planning Act 2008 (as amended) (Ref. 8-1) establishes a regime for grating DCOs for NSIPs and provides for the Government to produce NPSs. Responsibility for receiving and examining DCO applications lies with the Planning Inspectorate, which will make a recommendation to the relevant SoS.

8.2.2. The Planning Act 2008 enables the SoS to designate a statement as a NPS, if it sets out national policy in relation to specified descriptions of nationally significant infrastructure development. A number of NPSs relating to energy infrastructure (including technology specific NPSs) were designated by the SoS for the Department of Energy and Climate Change (DECC) in July 2011.

8.2.3. The Proposed Development will produce up to 1,400MWe net from combusting natural gas (using some distillate fuel in the case of a black start event), and therefore exceeds the 50MWe criterion set out in the Planning Act and NPSs for NSIPs. As such, the designated NPSs listed below are considered relevant to the determination of this DCO Application.

• Overarching NPS for Energy EN-1 (Ref. 8-2): This document sets out national policy for energy infrastructure as defined by the Planning Act and provides an umbrella document under which all other energy NPSs sit. The policies within this NPS, in combination with policies set out in relevant technology specific energy NPSs, provide the primary basis for

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decisions by the SoS for Energy and Climate Change (the Secretary of State) and set out the need for new energy infrastructure.

• NPS for Fossil Fuel Electricity Generating Infrastructure (EN-2) (Ref. 8-3): This sets out policies specific to the determination of applications for fossil fuel electricity generating infrastructure.

• NPS for Electricity Networks Infrastructure (EN-5) (Ref. 8.4): This sets out the policies specific to the determination of applications for above ground electricity lines whose nominal voltage is expected to be 132kV or above.

8.2.4. Part 3 of EN-1 defines and sets out the ‘need’ that exists for nationally significant energy infrastructure. Paragraph 3.1.1 states that the UK needs all the types of energy infrastructure covered by the NPS in order to achieve energy security at the same time as dramatically reducing greenhouse gas emissions. Paragraph 3.1.2 of the NPS goes on to state that it is for industry to propose new energy infrastructure and the Government does not consider it appropriate for planning policy to set targets for or limits on different technologies.

8.2.5. Notably, paragraph 3.1.3 of the NPS stresses that the SoS should assess applications for Development Consent for the types of infrastructure covered by the energy NPSs on the basis that the Government has demonstrated that there is a need for those types of infrastructure. Paragraph 3.1.4 of the NPS continues that the SoS should give substantial weight to the contribution that projects would make towards satisfying this need. As such, the ‘need’ for energy infrastructure is not open to debate or interpretation.

8.2.6. In making decisions on NSIPs, the SoS must also have regard to any local impact report submitted by a relevant local authority, any relevant matters prescribed in regulations and other matters that the SoS thinks are both important and relevant to his/her decision. Other matters that may be considered both important and relevant may include local development plan documents (DPDs). The NPSs provide guidance on assessment principles and identify a number of generic impacts relating to energy infrastructure that applicants should consider in preparing their application and which the SoS should have regard to in determining applications.

8.2.7. The SoS is required to determine applications for Development Consent in accordance with the relevant NPSs unless this would:

• Lead to the UK being in breach of its international obligations;

• Be in breach of any statutory duty that applies to the SoS;

• Be unlawful by virtue of any enactment;

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• Result in adverse impacts from the development outweighing the

benefits; or

• Result in any condition prescribed for deciding an application otherwise than in accordance with a national policy statement being met.

8.2.8. The energy NPSs also provide guidance on the principles to be applied in assessing applications for Development Consent and identify a number of generic and technology specific impacts relating to energy infrastructure that applicants should consider in preparing their applications and which the SoS should have regard to in making decisions.

8.2.9. The scope of the EIA undertaken will address the requirements set out in the energy NPSs EN-1 (Ref 7-1), EN-2 (Ref 7-2) and EN-5 (Ref 7-3). In particular, the scope will take account of EN-1 Part 4 ‘Assessment Principles’ and Part 5 ‘Generic Impacts’ and EN-2 Part 2 ‘Assessment and technology-specific information’. In relation to EN-2 Part 2 the relevant matters will be considered in the EIA on a topic-by-topic basis, which will include specifying what is required in terms of an ‘applicant’s assessment’ and ‘decision making’ and 'mitigation'.

8.2.10. The requirements of the NPSs, as well as local planning policies, are considered in detail in each of the specialist assessment chapters contained in this PEI Report, with an overview of the specific policies presented in Appendix D, Volume II of this report. The final ES to be submitted with the DCO Application will include a record of how relevant NPS policy requirements have been considered and will provide information needed to determine the application in accordance with the NPSs.

8.2.11. The need for the Proposed Development is discussed in Chapter 6: Project Need and Alternatives of this PEI Report. Compliance with planning policy will also be considered within the DCO Application Supporting Statement, submitted with the DCO Application.

8.3. Other Relevant National Policy

8.3.1. NPS EN-1 states that consideration may be given to planning policy outside the NPSs where it is important and relevant to the SoS’s decision. NPS EN-1 states in paragraph 4.1.5 that where there is any conflict between an NPS and another policy document, the NPS shall prevail for the purposes of determination of an application for a DCO by the SoS.

8.3.2. Other national planning policies have been considered in the preparation of this PEI Report and, where relevant, are described further in each of the topic chapters. National planning policy is predominantly contained in the National Planning Policy Framework (NPPF) (Ref. 8-5). The NPPF does not contain

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specific policies for nationally significant infrastructure projects, but its policies can be relevant to the determination of a DCO Application.

8.3.3. The following National Planning Policy and Guidance are adopted:

• NPPF – sets out national planning policy and how this should be applied.

• NPPF Technical Guidance (Ref. 8-6) – seeks to ensure the effective implementation of the NPPF in areas at risk of flooding and in relation to minerals extraction.

8.4. Local Planning Policy

The Development Plan 8.4.1. The DCO Site boundary includes land within the administrative areas of SGC and

BCC. The adopted Development Plan for the anticipated DCO Site, as defined by Section 38 (6) of the Planning and Compulsory Act 2004 (Ref. 8-7), includes the documents listed below.

Adopted Development Plan – South Gloucestershire Council

8.4.2. The following documents form the Adopted Development Plan for SGC:

• South Gloucestershire Core Strategy 2006 - 2027 (Ref. 8-8).

• South Gloucestershire Local Plan, adopted 2006 (saved policies) (Ref. 8-9).

• West of England Joint Waste Core Strategy, adopted March 2011 (Ref. 8-10).

• South Gloucestershire Minerals and Waste Local Plan, adopted 2002 (saved policies) (Ref. 8-11).

Adopted Development Plan – Bristol City Council

8.4.3. The following documents form the Adopted Development Plan for BCC:

• Bristol Core Strategy, adopted June 2011 (Ref. 8-12).

• Bristol Local Plan, adopted 1997 (saved policies) (Ref. 8-13).

• West of England Joint Waste Core Strategy, March 2011 (Ref. 8-10).

The Emerging Development Plan

8.4.4. SGC and BCC are also in the process of preparing new development plan documents. These emerging development plan documents are listed below.

May 2014 Page 8-4

Seabank 3


Emerging Development Plan Documents

8.4.5. BCC has drafted the Bristol Site Allocations and Development Management Development Plan Document (Ref. 8-14).

8.4.6. The Bristol Site Allocations and Development Management Policies Publication Version was submitted to the SoS on 12 July 2013 for independent examination.

8.4.7. The policies of this emerging development plan document have not yet been adopted, but could be material to the DCO Application, especially if they have undergone public disclosure.

8.4.8. Whilst not part of the development plan under the Planning and Compulsory Purchase Act 2004, the emerging development plan document has been taken into account in the preparation of this PEI Report and, where relevant, is considered further within each of the topic chapters.

Other Local Policy

8.4.9. Other local policy documents can be taken into account in the determination of the applications for DCO if the SoS considers them important and relevant.

8.4.10. SGC has prepared the Supplementary Planning Documents (SPDs) and Supplementary Planning Guidance (SPGs) listed below, which could be relevant to the consideration of the DCO Application:

• South Gloucestershire Planning Guidance: Biodiversity in the Planning Process (SPG), adopted November 2005 (Ref. 8-15);

• South Gloucestershire Design Guide: Sustainable Drainage Systems (SPG), adopted 2002 (Ref. 8-16);

• South Gloucestershire Planning Guidance: Trees on Development Sites (SPG), adopted November 2005 (Ref. 8-17);

• South Gloucestershire Design Guide: Waste Audits (SPG), adopted July 2002 (Ref. 8-18);

• South Gloucestershire Landscape Character Assessment SPD, adopted July 2005 (Ref. 8-19);

• South Gloucestershire Design Checklist SPD, adopted August 2007 (Ref. 8-20).

8.4.11. SPDs and SPGs adopted by BCC, which may be relevant to the consideration of the DCO Application, include the documents listed below.

• Waste and Recycling: Collection and Storage Facilities – Guidance for developers, owners and occupiers, January 2010 (Ref. 8-21);

May 2014 Page 8-5

Seabank 3


• Supplementary Planning Document 1: Tall Buildings, adopted January

2005 (Ref. 8-22);

• Supplementary Planning Document 5: Sustainable Building Design and Construction, adopted February 2006 (Ref. 8-23);

• Supplementary Planning Document 7: Archaeology and Development, adopted March 2006 (Ref. 8-24);

• Bristol Local Plan Policy Advice Note 2: Conservation Area Enhancement Statements; November 1993 (Ref. 8-25);

• Bristol Local Plan Policy Advice Note 14: Safety and Security, June 1997 (Ref. 8-26);

• Bristol Local Plan Policy Advice Note 15: Responding to Local Character, March 1998 (Ref. 8-27).

8.5. References

Ref. 8-1 Planning Act 2008 (Great Britain) Ref. 8-2 Department for Energy and Climate Change (2011) Overarching

National Policy Statement for Energy (EN-1) Ref. 8-3 Department for Energy and Climate Change (2011) National Policy

Statement for Fossil Fuel Electricity Generating Infrastructure (EN-2) Ref. 8-4 Department for Energy and Climate Change (2011) National Policy

Statement for Electricity Networks Infrastructure (EN-5) Ref. 8-5 Department for Communities and Local Government (2012) National

Planning Policy Framework Ref. 8-6 Department for Communities and Local Government (2012) Technical

Guidance to the National Planning Policy Framework Ref. 8-7 Planning and Compulsory Purchase Act 2004 (Great Britain) Ref. 8-8 South Gloucestershire Council (2013) South Gloucestershire: Core

Strategy 2006 – 2027, Adopted December 2013 Ref. 8-9 South Gloucestershire Council (2006) South Gloucestershire Local

Plan (saved policies) Ref. 8-10 West of England Partnership (2011) West of England Joint Waste

Core Strategy Ref. 8-11 South Gloucestershire Council (2002) South Gloucestershire Minerals

and Waste Local Plan (saved policies) Ref. 8-12 Bristol City Council (2011) Bristol Core Strategy Ref. 8-13 Bristol City Council (1997) Bristol Local Plan (saved policies) Ref. 8-14 Bristol City Council (2013) Bristol Site Allocations and Development

Management Development Plan Document Publication Version Ref. 8-15 South Gloucestershire Council (2005) South Gloucestershire

Planning Guidance: Biodiversity in the Planning Process, adopted November 2005

May 2014 Page 8-6

Seabank 3


Ref. 8-16 South Gloucestershire Council (2002) South Gloucestershire Design

Guide: Sustainable Drainage Systems SPG Ref. 8-17 South Gloucestershire Council (2005) South Gloucestershire

Planning Guidance: Trees on Development Sites SPG Ref. 8-18 South Gloucestershire Council (2002) South Gloucestershire Design

Guide: Waste Audits SPG Ref. 8-19 South Gloucestershire Council (2005) South Gloucestershire

Landscape Character Assessment SPD Ref. 8-20 South Gloucestershire Council (2007) South Gloucestershire Design

Checklist SPD Ref. 8-21 Bristol City Council (2010) Waste and Recycling: Collection and

Storage Facilities – Guidance for developers, owners and occupiers Ref. 8-22 Bristol City Council (2005) Supplementary Planning Document 1: Tall

Buildings Ref. 8-23 Bristol City Council (2006) Supplementary Planning Document 5:

Sustainable Building Design and Construction Ref. 8-24 Bristol City Council (2006) Supplementary Planning Document 7:

Archaeology and Development Ref. 8-25 Bristol City Council (1993) Bristol Local Plan Policy Advice Note 2:

Conservation Area Enhancement Statements Ref. 8-26 Bristol City Council (1997) Bristol Local Plan Policy Advice Note 14:

Safety and Security Ref. 8-27 Bristol City Council (1998) Bristol Local Plan Policy Advice Note 15:

Responding to Local Character

May 2014 Page 8-7

Seabank 3 PEI Report - Chapter 9 Land Use, Recreation and Socio-economics

May 2014 Page 9-1

9. Land Use, Recreation and Socio-economics

9.1. Introduction

9.1.1. This chapter of the PEI Report assesses the land use, recreational and socio-

economic effects of the Proposed Development and associated infrastructure. In

particular, this chapter comprises:

• An economic impact assessment, including employment impacts on the

labour market and additional local spending; and

• Consideration of the effect on land use and recreational activity resulting

from the Proposed Development and associated infrastructure.

9.1.2. This chapter describes the assessment methods and significant criteria used;

baseline conditions; potential direct, indirect and induced effects during the

construction, operational and decommissioning phases of the Proposed

Development and associated infrastructure; any mitigation measures to maximise

local regeneration opportunities; and wider land use, recreation and socio-

economic effects.

Consultation

9.1.3. A scoping request was submitted to the Planning Inspectorate in February 2013

to allow stakeholders the opportunity to comment on the proposed structure,

methodology and content of this chapter and subsequent ES. A summary of

stakeholder comments and how they have been incorporated into this PEI Report

chapter is provided in Table 9-1.

Table 9-1: Relevant Scoping Opinion Responses

Stakeholder Comment Addressed within the Report


The Applicant should engage with Natural England to determine the potential for impacts associated with diverting a public right of way.

No rights of ways will be permanently diverted. A new public right of way will be created, which is discussed in section 9.5 of this chapter.

The types of jobs generated should be considered in the context of the available workforce in the area, this applies equally to the construction and operational stages.

See section 9.5 of this chapter.

The assessment criteria should be locationally specific and consider the potential significance of the impacts of the proposal within the local and regional context.



May 2014 Page 9-2


Land use both within and outside of the site should be considered within the ES and should include an assessment of whether the proposed power station is likely to result in constraints on adjacent land uses.

See section 9.4 and 9.5.

Details should be provided outlining proposed measures to ensure the safe use of public rights of way during the construction phase of the development.

See section 9.5 of this chapter and Chapter 10: Traffic and Transport

The assessment of the effects of the proposed development on agricultural land should be included within the ES.

As explained in Chapter 2: The DCO and EIA Process, this PEI Report does not assess the Site’s agricultural potential (which is considered to be low).

The effect of atmospheric emissions on surrounding agricultural land is assessed in Chapter 11: Air Quality.

The impacts upon users of the Severn Estuary should be assessed within the ES and should include impacts on both commercial and recreational sailing and fishing.

This comment has been superseded by the decision not to include direct cooling (which would have required a pipeline into the estuary) - see Chapter 6: Project Need and Alternatives. Given there will be no marine effects associated with the Proposed Development this has therefore been scoped out of the assessment.

SGC It is recommended, for clarity and because of the very different issues of land use and socio economics versus recreation (relating to public rights of way and bridleways), that these issues are split into separate sections of the EIA.

Sections 9.4 and 9.5 of this chapter provide separate subheadings for land use and socio economics verses recreation.

The EIA should consider the wider context of proposed access links for horses and other users including the Local Plan LC12 routes and a future link with Minors Lane.

See section and 9.5 of this chapter.

It will also be important to consider whether the proposed development has any bearing on or constraint to adjacent land uses.

See section and 9.5 of this chapter.

BCC No additional comments -

Legislation and Planning Policy Context

9.1.4. A summary of legislation and planning policy relevant to this assessment is

provided in Appendix D: Volume II of this PEI Report.


May 2014 Page 9-3

9.2. Assessment Methodology and Significance Criteria

9.2.1. This assessment seeks to establish the potential economic and social effects of

the Proposed Development and associated infrastructure and assess these

effects against the current baseline. The effects of the Proposed Development

and associated infrastructure are considered at defined spatial levels according

to the nature of the impact considered. This approach is consistent with the

Department for Business Innovation and Skills (BIS) publication ‘Research to

Improve the Assessment of Additionality’ (Ref. 9-1).

Assessment Methodology

9.2.2. The following assessment seeks to establish the potential economic and social

contributions of the Proposed Development and associated infrastructure, and

assesses the expected effects against the current baseline position. A range of

data sources, including the Office for National Statistics, Nomis, and Annual

Business Inquiry (ABI) have been used to establish the baseline. Other

secondary sources have also been used and guidance taken from HM Treasury’s

Green Book.

9.2.3. The principal economic effect of the Proposed Development is considered

relative to the Travel to Work Area (TTWA) for the DCO Site, which includes

Bristol, South Gloucestershire, and North Somerset in the ‘Bristol TTWA’.

9.2.4. It is anticipated that as the Proposed Development Site is located in South

Gloucestershire and close to Bristol, the project TTWA will fit with that of the

Bristol TTWA. The 2001 Census indicates that 88.2% of workers live inside the

Bristol TTWA whilst 11.8% live outside (Ref. 9-2). The population of Bristol and

South Gloucestershire is therefore considered to be an appropriate study area for

the Proposed Development. This labour market incorporates the population that

may reasonably be expected to travel to, and benefit from, the Proposed

Development.

9.2.5. Impacts on social and community infrastructure vary by geographical impact

areas, according to the latest socio-economic data or policy available.

9.2.6. Table 9-2 presents the different components of the assessment and the

geographical scale at which they are assessed.


May 2014 Page 9-4

Table 9-2: Socio-economic Effects by Geographical Scale

Effect Geographical Area of Effect

Study Area for this assessment

Employment generation during construction and operation phases (direct, indirect and induced impacts)

Bristol, South Gloucestershire

TTWA

Additional local spending Bristol, South Gloucestershire

TTWA

Changes in land use and effects on PROW Immediate area DCO Site and immediate surrounds

Effects on local tourism and visitor numbers Immediate area DCO Site and immediate surrounds

9.2.7. The scale of significance described below, together with expert judgment has

been used to assess the potential and residual effects of the Proposed

Development and associated infrastructure against the baseline conditions.

9.2.8. The assessment has been based on the maximum design parameters, which

assumes two HRSG and turbine buildings (i.e. two CCGT units) and a peaking

plant facility, with associated development and infrastructure. It is feasible that

the effects assessed in this chapter may be overestimated if the Proposed

Development is not fully built out (e.g. if one CCGT unit is constructed), however

although this might affect the number of jobs and spending created, it is not

expected to change the level of significance that has been assigned to the

residual effects. The employment numbers would also be similar regardless of

whether the maximum and minimum parameters laid out in Chapter 4: Project

Description was implemented.


9.2.9. In line with the criteria set out in Chapter 7: Assessment Methodology, effects

have been classified as either:

• Adverse - Detrimental or negative effects to an environmental/socio-

economic resource or receptor; or

• Beneficial - Advantageous or positive effect to an environmental /socio-

economic resource or receptor.

9.2.10. The magnitude of a change caused by an effect is its severity or scale. The

magnitude of a change reflects consideration of information and analysis relating

(dependent on the type of receptor) variously to (where relevant):

• Spatial extent of the effect - Local level (DCO Site or neighbouring

receptors); District level (i.e. within Bristol / South Gloucestershire);


May 2014 Page 9-5

Regional level (South West England region), National level (UK); or

International level.

• Duration (short to medium term [generally associated with the

construction phase], and long-term effects are those associated with the

completed and operational Proposed Development

• Permanency of the effect – reversible or permanent

9.2.11. For effects described as Beneficial or Adverse, significance levels are defined as:

• Negligible – Imperceptible change, either due to its magnitude, extent or

duration, which is clearly not significant; or

• Minor - Slight, very short or highly localised effect that is not significant;

or

• Moderate - Limited effect (by extent, duration or magnitude) but which

may be considered significant; or

• Major - Considerable effect (by extent, duration or magnitude) of more

than local significance which is clearly significant.

9.2.12. Moderate and major effects are judged to be significant for the purposes of this

assessment and the wider EIA.

9.2.13. The complexity of interactions between these factors when affecting socio-

economic receptors means that it has not been considered appropriate to set out

precise quantitative measures for this chapter. However, the assessment process

has ascertained information in respect to the above factors and professional

judgement has been employed to evaluate the significance of the effects.

Key Parameters for Assessment

9.2.14. This assessment employs the ‘Rochdale Envelope’ approach (as detailed in the

Planning Inspectorate Advice Note 9) and described in Chapter 2: The DCO and

EIA Process.

9.2.15. The variation in building dimensions presented in Chapter 4: Project Description

under the ‘Rochdale Envelope’ principle is an important consideration for this PEI

Report. However it is not considered that the flexibility in building location or

heights and footprints would have a material effect on this assessment. As noted

above, the programme and number of workers would be similar regardless of this

level of flexibility and would not affect the conclusions of this assessment.


May 2014 Page 9-6

9.3. Baseline Conditions

9.3.1. This section establishes the current baseline with regards to the following

characteristics relevant to the Proposed Development and associated

infrastructure:

• Population;

• Skills and Education;

• Economy;

• Labour Profile;

• Land Use; and

• Tourism.

9.3.2. Potential effects arising from the Proposed Development are assessed relative to

the baseline effect areas set out in Table 9-1 and benchmarked against regional

and national standards where appropriate.

Population

9.3.3. The population of the study area, which comprises Bristol and South

Gloucestershire, increased by 8.7% from 637,500 in 2002 to 698,600 in 2012

(Ref. 9-3). Over the same period the population of South West England

increased by 6.8% and the population of the UK increased by 6.8% (Ref. 9-4).

Skills and Education

9.3.4. The working age population (defined as 16 to 64 by the Office for National

Statistics (ONS)) in the study area is well skilled compared to the rest of South

West England and the UK. In 2012, 38.6% of the study area’s working aged

population had an NVQ4 or higher, compared to 34.1% in South West England

and 34.2% in the UK (Ref. 9-4).

9.3.5. 8.1% of its working age population in the study area is shown to have no

qualifications, compared to 7.0% in South West England and 9.9% in the UK.

9.3.6. Table 9-3 outlines the qualification levels of the study area population, compared

to South West England and the UK.


May 2014 Page 9-7

Table 9-3: Qualification Levels of the Working Population (aged 16-64)

Qualification Study Area South West England

United Kingdom

NVQ4+ 38.6% 34.1% 34.2%

NVQ3 17.0% 18.8% 17.1%

NVQ2 16.0% 18.2% 16.8%

NVQ1 11.9% 12.9% 12.1%

Other Qualifications 5.4% 4.9% 6.3%

No Qualifications 8.1% 7.0% 9.9%

Source: ONS (2013); Annual Population Survey

Economy

9.3.7. The study area had a working age population of 493,500 between July 2012 to

June 2013, 80.0% of which were economically active (Ref. 9-4). For comparison,

79.0% of the working age population in South West England were economically

active during this same period, whilst the UK had a rate of 77.1% (Ref. 9-4).

9.3.8. The employment rate of the study area was 73.4%, which was lower than South

West England, which had a rate of 74.3%, although higher than the UK’s rate of

71.0% (Ref. 9-4).

9.3.9. The unemployment rate was higher in the study area (8.3%) than either South

West England (6.0%) or the UK (8.0%) (Ref. 9-4).

Labour Profile

9.3.10. The study area has a high proportion of people employed in professional

occupations (23.1%) than in both South West England (18.8%) and UK (19.6%)

(Ref. 9-4). However it also has a slightly lower proportion of people employed as

managers, directors and senior officials (10.0%) than the South West England

(10.3%) or UK averages (10.1%) (Ref. 9-4).

9.3.11. Fewer people are employed in elementary occupations in the study area (10.5%)

when compared to South West England (11.3%) and the UK (10.9%) (Ref. 9-4).

9.3.12. The distribution of employment by occupation is outlined below in Table 9-4

below.


May 2014 Page 9-8

Table 9-4: Employment by Occupation, July 2012 to June 2013

Occupation Study Area

(%) South

West (%) UK (%)

Managers, directors and senior officials 10.0 10.3 10.1

Professional occupations 23.1 18.8 19.6

Associate prof & tech occupations 14.1 13.7 13.9

Administrative and secretarial occupations 10.5 10.7 10.9

Skilled trades occupations 10.1 12.2 10.6

Caring, leisure and other service occupations 8.1 9.1 9.0

Sales and customer service occupations 8.1 7.7 8.0

Process, plant and machine operatives 5.3 5.7 6.3

Elementary occupations 10.5 11.3 10.9

Source: Annual Population Survey 2013

9.3.13. The work force in the study area are employed across a range of sectors, with

wholesale and retail trade and the repair of motor vehicles employing the

greatest proportion of workers, which is 15.0% (Ref. 9-5). This is slightly less than

the 17.2% in South West England and 16.0% in Great Britain for this sector (Ref.

9-5). The Avonmouth Severnside Outline Development Strategy (Ref. 9-6)

highlights the ‘Distribution and Logistics’ sector as a key sector locally given the

scale of employment it supports.

9.3.14. The study area has a greater proportion of people employed in services (such as

professional, scientific and technical activities) than South West England or Great

Britain. However, it also has a smaller proportion of people employed in

manufacturing and utilities related activities than South West England and Great

Britain. The distribution of employment across sectors is outlined in Table 9-5

below.

9.3.15. Of direct relevance to the Proposed Development, approximately 750 people

(0.2%) of the labour market were employed in electricity, gas, steam and air

conditioning activities (Ref. 9-11). This is half the proportion for this sector

compared to South West England (0.4%) and Great Britain (0.4%) (Ref. 9-5).

However, the energy sector is considered a key sector within the Avonmouth

Severnside Outline Development Strategy (Ref. 9-6) despite its relatively low

share of employment.

9.3.16. The construction sector accounts for 4.4% of employment, in line with the

national average. This accounts for approximately 17,200 people in the local

labour market.


May 2014 Page 9-9

Table 9-5: Sector Employment Distribution, 2012

Sector Study Area (% of

employment)

South West (%)

Great Britain (%)

Agriculture, forestry and fishing 0.0 1.2 0.8

Mining and quarrying 0.1 0.1 0.2

Manufacturing 7.5 9.8 8.6

Electricity, gas, steam and air conditioning supply

0.2 0.4 0.4

Water supply; sewerage, waste management and remediation activities

0.6 0.8 0.7

Construction 4.4 4.5 4.5

Wholesale and retail trade; repair of motor vehicles and motorcycles

15.0 17.2 16.0

Transportation and storage 4.1 3.6 4.5

Accommodation and food service activities 5.8 8.6 6.8

Information and communication 4.4 2.9 3.9

Financial and insurance activities 6.8 3.6 3.9

Real estate activities 1.5 1.6 1.6

Professional, scientific and technical activities 8.4 6.0 7.5

Administrative and support service activities 9.1 6.3 8.3

Public administration and defence; compulsory social security

6.4 5.1 5.0

Education 9.1 9.8 9.5

Human health and social work activities 13.1 14.2 13.4

Arts, entertainment and recreation 1.8 2.3 2.5

Other service activities 1.8 2.0 1.9

Total 100.0 100.0 100.0

Source: Business Register and Employment Survey 2012

Land Use

9.3.17. Chapter 3: The Site and Its Surroundings provides a description of the land uses

within close proximity to the Proposed Development.

9.3.18. In summary, the Proposed Development Site is predominantly grass fields,

dissected by rhines, located on the periphery of an existing industrial area. The

nearest residential communities include Severn Beach, Hallen, Pilning and

Easter Compton, approximately 1.5km north, 2km south east, 2.2km north east

and 3km east of the Proposed Development Site respectively. Isolated dwellings

are located 1.1km to the east of the Proposed Development Site.

9.3.19. The proposed below ground cooling water pipeline will follow the route of the

existing Wessex Water supply and return pipelines to the Seabank 1 & 2


May 2014 Page 9-10

generating station, which are beneath or adjacent to a number of PROW and

extends along grass verges and existing hardstanding within the Severnside and

Avonmouth industrial areas to the Bristol WWTW.

Public Rights of Way (PROW)

9.3.20. There are a number of recognised PROW within close proximity to the DCO Site

as illustrated in Figure 3-4a, Figure 4-4b and Figure 3-4c, Volume III of this PEI

Report.

9.3.21. The closest PROW to the Proposed Development Site extends from Minor’s Lane

for approximately 450m, to the west of Minor’s Farm (derelict) and across farm

land, currently ceasing at the southern boundary of the Proposed Development

Site. No PROWs currently exist within the Proposed Development Site itself.

9.3.22. There are also a number of PROWs close to or within the DCO Site. The

proposed cooling water pipeline corridor extends along the route of an existing

PROW alongside the railway track, around St Martin’s Industrial Park and within

close proximity to Moorend Farm Avenue.

Leisure and Recreational Activities

9.3.23. The Proposed Development Site primarily comprises open grass fields dissected

by a network of rhines. It is likely that only limited leisure or recreational activity

such as dog walking, rambling, horse-riding, cycling and jogging takes place in

the vicinity of the Proposed Development. This is because there are no formal

leisure facilities nearby and the nearest settlement is approximately 2.5km away,

which would deter many recreational users. The high concentration of industrial

land uses within the area is also likely to deter leisure users and the M49 creates

a barrier effect from the east.

9.3.24. Open grass fields of similar quality to those near to the DCO Site can be found

closer to local communities. These are therefore more likely to be used for leisure

and recreational uses than those near to the DCO Site.

Tourism

9.3.25. VisitEngland (Ref. 9-7) publishes figures relating to visitor volumes and the value

of the tourism industry on a national, regional and Local Authority level. The

tourism sector in South West England is strong with a total of 19.2 million

domestic overnight trips in South West England, accounting for 20% of all trips in

England and generating £3,606m in tourism spend. In addition, 2.1 million

inbound trips in South West England generated an estimated £902m in spend.

Tourism is also an important part of South Gloucestershire’s economy with 4.6


May 2014 Page 9-11

million day visits and 1.5 million overnight stays per year generating around £300

million in tourism related spend.

9.3.26. The local area within close proximity to the DCO Site does not have significant

historic features, landscapes or tourism attractions, with the exception of Blaise

Castle Estate - a 650 acre Grade II* registered parkland including children's play

area, museum and castle, which is approximately 4km southeast from the

Proposed Development Site. The Estate is open daily and is free to enter. It

includes the Blaise Castle Museum and Blaise Hamlet which is a National Trust

property, both of which are tourist destinations that attract approximately 530,000

visitors a year (Ref. 9-8).

9.3.27. The Castle Estate is ranked outside the top 20 free visitor attractions in South

West England, all of which attract at least 625,000 visitors a year (Ref. 9-9).

9.3.28. Urban development, woodland, farmland and the M5 and M49 lie between Blaise

Castle and the DCO Site forming significant separation. Neither site is visible

from the other.

9.3.29. There are a significant number of other historical features and tourism attractions

in the study area, given Bristol’s status as one of the UK’s most significant

historic cities. None of these tourism features are within 5km of the Proposed

Development and associated infrastructure however and are unlikely to be

affected by either the construction or operational development. These sites have

not been considered further therefore.

9.4. Development Design and Impact Avoidance

9.4.1. There are limited avoidance measures that have been implemented in the design

of the Proposed Development relevant to land use, recreation and socio-

economics.

9.4.2. The Proposed Development does however incorporate a proposed PROW that

would connect Ableton Lane to the south of the Proposed Development Site to

the existing roundabout that is situated immediately east of the Proposed

Development Site, via a new cycle path, footpath and bridleway that would

extend along the southern boundary of the CCR Site, as illustrated in Figure 4-2

and 4-3 in Volume III of this PEI Report. This is discussed further below.

9.4.3. Additional mitigation measures and industry standard control measures are

discussed in the following section.


May 2014 Page 9-12

9.5. Potential Effects and Mitigation Measures

9.5.1. This section analyses the scale, duration (e.g. short-term, medium-term or long-

term) and significance of potential socio-economic effects attributed to the

Proposed Development and associated infrastructure against the baseline

established in the previous sections.

9.5.2. This section does not include cumulative schemes; this is addressed in section

9.7.

Construction Employment

9.5.3. The following sub-sections assess the net impact of the Proposed Development

and associated infrastructure in terms of construction jobs on the local and

regional economies of the Bristol TTWA and South West England.

9.5.4. The enabling works and construction period for the DCO Site is expected to last

54 months, as described in Chapter 5: Enabling Works and Construction. This

section focusses on the construction phase (following enabling works), which is

expected to last around 37 months and will result in greater socio-economic

effects than the enabling works.

Direct Construction Employment

9.5.5. The employment resulting from the construction phase has been calculated

based on the construction schedule provided by one of the possible construction

contractors based on work done on a number of previous and similar projects. It

excludes the 17 months of enabling works, which may be undertaken by a

separate Contractor and is expected to employ a smaller number of workers (an

expected 5- 20 workers onsite).

9.5.6. The schedule indicates that the number of construction workers will vary from a

minimum of around 25 in the first month to a peak of 800 in the 25th month of

construction (anticipated to occur in late 2019 based on the current expected

programme), and falling to around 130 in the final month prior to commissioning.

Onsite construction employment is expected to be significantly lower in the first

eight and final three months of construction. The profile of construction

employment (excluding enabling works) is presented in Plate 9-1 below.


May 2014 Page 9-13

Plate 9-1: Profile of Construction Employment (excluding enabling works)

9.5.7. Based on the peak year of construction (from month 18 to month 29 of the

construction activities, which is expected to coincide with 2019), the expected

average workers per year generated by the Proposed Development construction

phase is 761 gross full time equivalents (FTEs). The average workers per year

generated over the entire 37 month construction period is 411.

9.5.8. Construction of the associated infrastructure related to the Proposed

Development, in particular the proposed cooling water pipeline, would also

generate additional construction employment, although this would be small in

comparison to the above. The construction of the electrical connection and

cooling water pipeline is expected to take approximately two years and would

create an estimated 100 full time equivalent jobs over this relatively short period.

Leakage

9.5.9. Leakage effects are the benefits to those outside the affected area. Analysis

carried out on Census 2001 data indicates that 11.8% of people working in the

Bristol TTWA live outside the TTWA (Ref. 9-2). This represents a ‘low’ level of

leakage as set out by BIS (Ref. 9-8) and implies that the majority of employment

opportunities would go to people living within the target area.

9.5.10. The figures regarding the potential for local employment generation provided in

this chapter are based on construction industry averages, but the final figures


May 2014 Page 9-14

achieved will be dependent on the selected contractor’s procurement strategy.

The appointment of the main contractor is subject to a competitive bidding

process and the main plant providers may be based outside the UK or choose to

partner with overseas civil contractors.

9.5.11. Considering the contractor appointment process, a medium level of leakage has

been assumed to reflect the possibility for the appointment of a contractor outside

of the Bristol TTWA. BIS guidance shows that a medium level of leakage is 25%

(Ref. 9-1). A 25% discount has therefore been applied to the estimated 761 jobs

that will be created during the peak year of construction of the Proposed

Development. As a result, it is estimated that 190 persons living outside of the

Bristol TTWA and 571 persons living within the Bristol TTWA would be working

on the Proposed Development during the construction period during the peak

year of construction activity.

9.5.12. The same discount was applied to the 100 short term construction jobs

associated with the construction of the cooling water pipeline. It is estimated that

25 persons living outside of the Bristol TTWA and 75 persons living within the

Bristol TTWA would be working on the cooling water pipeline during its two year

construction period.

Existing Employment

9.5.13. There is no existing construction employment onsite and as such there are no

‘deadweight’ effects that need to be considered in this assessment.

Displacement

9.5.14. Displacement measures the extent to which the benefits of a project are offset by

reductions of output or employment elsewhere. Additional demand for labour

cannot simply be treated as a net benefit as it removes workers from other posts

and the net benefit is reduced to the extent that this displacement occurs.

9.5.15. As described in the baseline, it is estimated that there are 17,200 construction

workers in employment within the study area (Ref. 9-5). The number of

construction workers that would be employed during the peak construction year

of the Proposed Development represents 3.3% of the total construction workforce

in the study area. Construction workers typically move between construction

projects when delays occur or to help the workforce meet particular construction

deadlines. Overall it is assumed that due to the flexibility of the labour market,

and the fact that construction workers at the Proposed Development represent a

small proportion of Bristol’s construction labour force, the displacement effects of

the direct construction employment would be low. BIS guidance shows that a low

level of displacement is considered to be 25% or less (Ref. 9 -2).


May 2014 Page 9-15

9.5.16. Displacement effects during the peak construction year of the Proposed

Development are equivalent to 190 FTEs, of which 143 would be from within the

Bristol TTWA.

9.5.17. Displacement effects during the construction of the proposed cooling water

pipeline are equivalent to 10 FTEs, of which 7.5 would be from within the Bristol

TTWA.

Multiplier Effects

9.5.18. In addition to the direct construction employment generated by the DCO Site

itself there would be an increase in local employment arising from indirect and

induced effects of the construction activity. Employment growth would arise

locally through manufacturing services and suppliers to the construction process

(indirect or supply linkage multipliers). Additionally, part of the income of the

construction workers and suppliers would be spent in the Bristol TTWA,

generating further employment (induced or income multipliers).

9.5.19. The impact of the multiplier depends on the size of the geographical area that is

being considered, the local supply linkages and income leakage from the area.

The BIS guidance provides a ‘ready reckoner’ of composite multipliers – the

combined effect of indirect and induced multipliers. The guidance suggests that

the majority of projects will have ‘average’ linkages based on the scale of its

economy. Therefore, a composite multiplier of 1.5 has been applied to this

assessment (Ref. 9-2).

9.5.20. Multiplier effects during construction of the Proposed Development are equivalent

to 285.5 FTEs, of which 214 would be from the within the Bristol TTWA.

9.5.21. Multiplier effects during construction of the cooling water pipeline are equivalent

to 15 FTEs, of which 11 would be from within the Bristol TTWA.

9.5.22. The multiplier effects generated by the construction of the Proposed

Development and associated infrastructure are greater than the displacement

effects, meaning that the construction phase would provide a net benefit in local

indirect employment.

Net Construction Employment associated with the Construction Phase

9.5.23. Table 9-6 below summarises the temporary employment estimated to be created

by the Proposed Development and associated infrastructure during construction

(taking leakage, displacement and multiplier effects into account).


May 2014 Page 9-16

Table 9-6: Net Construction Employment in Bristol TTWA during the Peak Construction Year

Predicted impact

Proposed Development Associated Infrastructure:


Bristol TTWA

Outside Bristol TTWA

Total Bristol TTWA


Total

Gross direct employment

571.0 190.0 761.0 30.0 10.0 40.0

Displacement 143.0 47.5.0 190.0 7.5 2.5 10.0

Net direct employment 428.0 143.0 571.0 22.5 7.5 30.0

Indirect & induced employment

214.0 71.5 285.5 11.0 4.0 15.0

Total net employment during peak construction

642.0 214.0 856.0 34.0 11.0 45.0

Source: URS calculations 2013. Note figures do not always add up due to rounding.*average no. of

construction workers per year

9.5.24. The total net additional construction employment created within the Bristol TTWA

by the Proposed Development in the peak year of construction is estimated to be

642 persons per year, with an additional 214 from outside the Bristol TTWA,

creating a total of 856 FTE jobs during the peak construction period, which is

anticipated to occur in 2019.

9.5.25. The total net additional construction employment created within the Bristol TTWA

from the cooling water pipeline is estimated to be 34 persons and an additional

11 persons from outside the Bristol TTWA, creating a total of 45 FTE jobs over its

one to two year construction period.

9.5.26. In the context of the existing construction labour market in the Bristol TTWA, the

direct, indirect and induced employment and expenditure created by the

temporary construction of the Proposed Development and associated

infrastructure are likely to have a moderate beneficial short-term effect on the

Bristol TTWA economy. This is due to the result of the scale of the construction

workforces in relation to the baseline position, representing 3.9% of the current

workforce.

Operational Employment

9.5.27. The following sections assess the net effect of the Proposed Development in

terms of operation jobs on the Bristol TTWA and South West England

economies.


May 2014 Page 9-17

9.5.28. The associated infrastructure is not expected to generate any additional

operational jobs. Servicing of the cooling water pipeline is expected to be

performed by existing Wessex Water staff.

Direct Operation Employment

9.5.29. The Proposed Development would generate long-term jobs once it begins

operating, currently expected to be from 2021. The effect of leakage, deadweight,

displacement and multiplier effects, during operation is presented below.

Leakage

9.5.30. The leakage effects of the operational phase of the Proposed Development are

expected to be lower than the leakage associated with the construction phase

because the operational employment will not be contracted in the same way as

the construction process. Analysis carried out on Census 2001 data indicates

that 11.8% of people working in the Bristol TTWA live outside the area (Ref. 9-2).

This represents a ‘low’ level of leakage as set out by BIS (Ref. 9-1) and implies

that the majority of employment opportunities would go to people living within the

target area. This been applied to the operational jobs to reflect the level of

leakage from the Bristol TTWA.

Deadweight

9.5.31. There is no existing operational employment onsite and as such there are no

deadweight effects that need to be considered.

Displacement

9.5.32. The displacement effects of the operational phase of the Proposed Development

are expected to be lower than the displacement associated with the construction

phase. This is because the scale of operational employment and its share of the

local workforce is significantly lower when compared to the construction phase,

and it requires specialist staff. Displacement effects have therefore been

assessed as being low (25%). This is the lowest level of displacement

recommended within BIS Guidance which has been used to calculate the net

employment generated by the operation of the Proposed Development (Ref. 9-1).

Multiplier Effects

9.5.33. In addition to the direct operation employment generated by the Proposed

Development itself there would be an increase in local employment arising from

indirect and induced effects of the operation activity. Employment growth would

arise locally through suppliers to the operation process (indirect or supply linkage

multipliers). Additionally, part of the income of the operation workers and


May 2014 Page 9-18

suppliers would be spent in the Bristol TTWA, generating further employment

(induced or income multipliers).

9.5.34. A composite multiplier of 1.5 has been applied to the assessment (Ref. 9-1).

Net Operation Employment

9.5.35. The Proposed Development is expected to generate 40 gross FTE jobs during

operation, as outlined in Table 4-2 of Chapter 4: Project Description.

9.5.36. In the event that Seabank Power Ltd chooses to invest in and operate the

Proposed Development in conjunction with Seabank 1 & 2 (and the Applicant

agreed), the number of long term jobs would reduce to an estimated 22 gross

FTE. This is due to efficiency savings, such as the requirement to have less

administrative and security staff if the two generating stations are managed as a

single entity.

9.5.37. The Proposed Development does not currently include any provisions for

management or operation by Seabank Power Ltd, however given that this cannot

be ruled out at this stage and it presents a worse-case scenario for the

operational jobs, it is considered prudent to also assess the effects on this basis,

to avoid inadvertently overestimating the job opportunities onsite.

Direct Operation Employment

9.5.38. Table 9-7 below presents the operational employment figures for both scenarios

(single site management by Seabank Power Ltd or independent management by

the Applicant), taking leakage, displacement and multiplier effects into account.

This includes the net employment onsite and offsite, including growth within

suppliers and external businesses that might benefit from the Proposed

Development.

9.5.39. Assuming a leakage of 11.8% outside the Bristol TTWA, a low level of

displacement at 25%, a 1.5 composite multiplier, and taking into account that

there are no ‘deadweight’ effects, it is estimated that the total net employment for

the Proposed Development under the Seabank Power Ltd operation scenario is

25 employees, of which 22 are from the Bristol TTWA. The total net employment

if operated independently is predicted to be 45 employees, of which 40 would be

expected to be from the TTWA.


May 2014 Page 9-19

Table 9-7: Net Operation Employment

Predicted impact Single Site Management with Seabank 1 & 2

Independently Managed by SSE

Bristol TTWA


Total Bristol TTWA


Total

Gross direct employment 19.5 2.5 22.0 35.0 5.0 40.0

Displacement 5.0 0.5 5.5 9.0 1.0 10.0

Net direct employment 14.5 2.0 16.5 26.5 3.5 30.0

Indirect & induced employment 7.0 1.0 8.0 13.0 2.0 15.0

Total net employment 22.0 3.0 25.0 40.0 5.0 45.0

Source: URS calculations 2013. Note figures do not always add up due to rounding.

9.5.40. The Proposed Development would displace some existing activity in the local

economy. The loss of expenditure and turnover from existing businesses would

be equivalent to 5 FTEs in the Bristol TTWA and 0.5 FTEs outside the Bristol

TTWA, increasing to 9 and 1 if the site is operated as an independent generating

station. This is the total displacement that is predicted would be caused by the

Proposed Development.

9.5.41. The indirect and induced effects from the Proposed Development would generate

an additional 8 employment opportunities, of which 7 would be created in the

Bristol TTWA. This increases to 15 and 13 if it is operated as an independent

site. As such the Proposed Development would make a positive contribution to

Bristol’s wider economy. The employees generated from multiplier effects are

also greater than the loss of employees from displacement.

9.5.42. The Proposed Development is therefore expected to create around 25 net jobs if

it is integrated with Seabank 1 & 2, and 45 net jobs if operated independently,

against a baseline position of 750 people currently employed within the electricity

and energy generation sector in the TTWA. Therefore, the direct, indirect and

induced employment created by the permanent employment of the Proposed

Development is likely to have a minor beneficial long-term effect on the Bristol

TTWA economy.

Land Use and Public Rights of Way (PROW)

9.5.43. The Proposed Development and associated infrastructure may be visible from

some parts of the PROW during the enabling works and construction period,

which could result in effects in terms of visual amenity. This is discussed further

in Chapter 17: Landscape and Visual Assessment.


May 2014 Page 9-20

9.5.44. The associated infrastructure related to the Proposed Development includes the

installation of a cooling water pipeline running from Seabank 1 & 2 to Bristol

WWTW. The proposed route of the cooling water pipeline runs across existing

PROWs including the long distance footpath, the Severn Way. It will therefore

cause some disruption to this existing PROW during the construction period.

However, any disruption to footpaths will be planned and notified in advance of

works taking place. Alternative routes will be provided during the construction

period wherever possible and once completed the existing PROW will remain in

their current positions. A temporary diversion will be provided for the Severn

Way.

9.5.45. The Proposed Development includes the provision of a new PROW from Albeton

Lane along the southern boundary of the CCR Site and to the existing

roundabout that lies immediately east of the CCR Site that forms the Spine

Access Road. It is envisaged this PROW would be landscaped and shall provide

footpath and cycle provisions, as well as a grass wayleave for bridleway,

meaning the route will contribute towards the aspirations of the South

Gloucestershire Core Strategy.

9.5.46. The South Gloucestershire Core Strategy recognises the Severnside area as a

strategic employment location and safeguards the Proposed Development Site

and surrounding area for extensive employment uses including energy

generation. Bearing in mind the nature of development being encouraged by the

Core Strategy, it is not considered that the Proposed Development would inhibit

future development of adjacent land.

9.5.47. Overall, the Proposed Development and associated infrastructure is considered

to have a long-term minor beneficial effect on land use and PROW. It is

expected that disruption to PROW will result from the proposed cooling water

pipeline construction but this is only temporary in nature and diversions will be

provided where possible. The provision of a new footpath adds value to the

existing infrastructure by providing a link between the PROWs to the north and

south of the Proposed Development Site, opening up these routes for commuting

and an associated increase in usage.

Leisure and Recreation

9.5.48. The baseline identified that current leisure and recreational usage of the DCO

Site is limited due to the quality of the open space and the relatively long distance

between nearby communities and the Proposed Development. Existing leisure

activity at the Proposed Development Site is expected to be nil currently, as it is

private land. It is therefore anticipated that the Proposed Development and

associated infrastructure will have a negligible effect on leisure and recreational

activity. This is due to the anticipated use and quality of the DCO Site for leisure


May 2014 Page 9-21

and recreational activity and the available of other sites of similar quality within

the local vicinity.

Tourism

9.5.49. The baseline identified the nearby presence of Blaise Castle Estate a tourism

feature that includes the Blaise Castle Museum and Blaise Hamlet.

9.5.50. Although The Castle Estate is considered to be a tourist attraction of local

importance, the existing character of the DCO Site and the surrounding area

means that the Proposed Development and associated infrastructure is only

considered to have a limited impact on tourism during either construction or

operational phases. This is because the Proposed Development is not expected

to change the view from or setting of the Castle (see Chapter 15: Archaeology

and Heritage and Chapter 17: Landscape and Visual) and is located within an

area that already includes other power generating facilities. The effect is

therefore considered to be a negligible long term effect.

Decommissioning

9.5.51. It is envisaged that the plant will have a design life of 30 years and an operating

life beyond this based on the number of operational hours, and decommissioning

would take approximately one year.

9.5.52. During the decommissioning period, the circa 25-45 net permanent jobs created

by the Proposed Development will be lost. Based on the current scale of the local

and regional workforce employed in electricity, gas, steam and air conditioning

activities, the magnitude of this change is considered to be low.

9.5.53. Based on information provided in the baseline regarding the local labour force in

the study area, it is assessed that the local economy has a low sensitivity to the

loss of jobs in electricity, gas, steam and air conditioning activities. This is

because these jobs contribute a low proportion of employment to the study area’s

total workforce and the size of the operational workforce is small.

9.5.54. Therefore, the decommissioning of the Proposed Development would be likely to

have a minor adverse (not significant) effect on the local economy.

9.5.55. The decommissioning phase will result in uncertain effects on the surrounding

land uses and recreation, due to the timescale of decommissioning. The

decommissioning process will be managed so as to minimise disruption and

change experience by surrounding receptors and resources. Therefore it is

assumed that the effect on these aspects will be negligible.


May 2014 Page 9-22

Mitigation Measures

9.5.56. To maximise the beneficial impacts for the residents of the district, where it is

within the control of the Applicant, there is an aim to source local labour where

practicable (dependant on skills being available locally). It would be appropriate

for the council to work in collaboration with Job Centre Plus and the Applicant to

identify opportunities for local recruitment.

9.5.57. No adverse effects have been identified and as such no mitigation measures are

required. Saying this, the Applicant will still encourage the sourcing of local

labour through active supply chain engagement. A ‘meet the buyer’ day will be

held where the Engineering, Procurement and Construction (EPC) contractor will

liaise with local businesses and suppliers. The Applicant has also created an

Open4Business (O4B) initiative which provides a dedicated web portal offering

visibility of business opportunities to the local community and suppliers, and

allows the Applicant to advertise contractual opportunities on the portal.

9.6. Residual Effects

9.6.1. It is considered that the Proposed Development and associated infrastructure

would have an overall positive economic effect on the Bristol TTWA economy,

through the provision of employment and through associated multiplier effects.

9.6.2. The construction of the Proposed Development would make a positive

contribution to the Bristol TTWA’s economy with 856 net employees expected to

be generated during the peak year of construction activity, of which 642 would be

from the Bristol TTWA. The construction of the cooling water pipeline is expected

to generate an additional 100 net FTE jobs, of which 75 would be in the Bristol

TTWA economy.

9.6.3. The operation of the Proposed Development would make a positive contribution

to the Bristol TTWA’s economy with between 25 and 45 net employees expected

to be generated on and offsite (depending on whether it is operated as a single

site or with Seabank 1 & 2). Of these net employees, the majority is expected to

be from the Bristol TTWA.

9.6.4. The Proposed Development would have a beneficial effect on the Bristol TTWA

economy, through employment opportunities and supply chain benefits to local

businesses. The Proposed Development will also provide additional social

benefits such as the provision of a new PROW.

9.6.5. A summary of the residual socio-economic effects of the Proposed Development

and associated infrastructure is provided in Table 9-8 below.


May 2014 Page 9-23

Table 9-8: Summary of Residual Effects

Aspect Duration and extent Significance

Employment generation during the construction phase (direct, indirect and induced effects)

Short term; Regional Moderate beneficial

Employment generation during the operational phase

Long term; Regional Minor beneficial

Land use and PROW Long term; Local Minor beneficial

Leisure, Recreation and Tourism

Long term; Local Negligible

Decommissioning Long term; Regional Minor adverse for employment

Negligible for land use, PROW and tourism

9.6.6. As mentioned in the Assessment Methodology section above, the assessment

has been based on the maximum design parameters for the Proposed

Development. It is feasible that the effects may have been overestimated if the

Proposed Development is not built out in full, however this is not expected to

change the level of significance that has been assigned to the residual effects.

9.7. Cumulative Effects

9.7.1. This section assesses the effect of the Proposed Development and associated

infrastructure in combination with the likely effect on the local economy arising

from other developments in the area, as outlined in Chapter 7: Assessment

Methodology.

9.7.2. Table 9-9 lists the cumulative schemes that are either similar in nature or scale to

the Proposed Development or sufficiently close to potentially lead to cumulative

effects. Existing schemes such as Seabank 1 & 2 form part of the baseline and

hence have not been discussed in this section.

Table 9-9: Summary of Schemes Relevant to Cumulative Socio-Economic Effects

Scheme Gross Construction

jobs

Gross Operation jobs

SITA Bottom Ash Facility, Severnside Energy Recovery Centre, Severn Road

200 9

Development of the Severnside Energy Recovery Centre, SITA

Data not provided in the ES

Data not provided in the ES

Helius Energy biomass fuel store and generating plant, Avonmouth Docks

264 40

E.On Climate & Renewables UK Developments Ltd biomass-fired renewable energy plant, Royal Portbury

300 40


May 2014 Page 9-24

Scheme Gross Construction

jobs

Gross Operation jobs

Dock

Viridor Resource Recovery Centre 200 65

Total 964 171

9.7.3. The above schemes are expected to create an additional 964 construction jobs

and 171 operational jobs, excluding the employment impact of Severnside

Energy Recovery centre for which information is not currently available from its

EIA. Other cumulative developments are presented in Chapter 7: Assessment

Methodology but have not been considered due to their distance from the DCO

Site, scale, or because they are at a preliminary stage of planning (for example

the proposed Avon Power Station).

9.7.4. When combined with the construction jobs resulting from the Proposed

Development and associated infrastructure, there would be a total of

approximately 1,865 short-term construction jobs. Based on the size of the

existing construction workforce in the study area the short-term cumulative

construction jobs would represent approximately 10.8% of this workforce.

Therefore the cumulative construction activities would have a moderate

beneficial effect on the Bristol TTWA and South West economy.

9.7.5. The operational jobs associated with the Proposed Development and the

operational jobs associated with the cumulative developments would create

approximately 196-216 jobs. Considering the size of the existing workforce in the

study area as presented in the baseline, the combined effect of the Proposed

Development with the cumulative schemes in terms of operational jobs would

create a moderate beneficial effect on the Bristol TTWA and South West

economy.

9.7.6. Given the absence of any adverse land use, recreation and leisure, and tourism

effects associated with the Proposed Development, it has not need deemed

necessary to assess the potential cumulative effects associated with these

aspects – any significant cumulative effects would be due to these other

schemes rather than the Proposed Development.

9.8. Impacts and Effects yet to be Determined

9.8.1. There are no impacts and effects yet to be determined, however, the scheme

design may be subject to change prior to submission of the final DCO application.

Any changes that lead to differing or new impacts and effects will be highlighted

within the final ES, along with the reasons for the change.


May 2014 Page 9-25

9.8.2. It is also possible that the baseline conditions will change between the

preparation of this PEI Report and the final ES; land use, recreation and socio-

economic conditions are dynamic and evolve over time. The Proposed

Development Site is currently subject to excavation, top soil stripping, and

levelling in certain areas in order for third parties to deliver the Spine Access

Road and new channel for the Red Rhine, which are discussed in Chapter 2: The

DCO and EIA Process and Chapter 7: Assessment Methodology. A haul road is

also being constructed through the middle of the Proposed Development Site to

enable access by third party from the roundabout to the east of the Site to the

Severnside Energy Recovery Centre to the west. These works onsite are being

undertaken by other developers, under extant planning permissions and are

separate to the Proposed Development.

9.8.3. The final ES will report on the baseline conditions considered relevant at the time

of submission, or an agreed point of time shortly before, as well as any changes

to the predicted magnitude of change or effects as a result of the changing

baseline conditions.

9.9. References

Ref. 9-1 Department for Business, Innovation and Skills (BIS), 2009: Research to Improve the Assessment of Additionality.

Ref. 9-2 Census, 2001: Travel to Work Areas.

Ref. 9-3 Office for National Statistics (ONS), 2013; Mid-Year Population Estimate 2012.

Ref. 9-4 ONS, 2013: Annual Population Survey, 2013.

Ref. 9-5 ONS, 2013: Business Register and Employment Survey (BRES) 2012.

Ref. 9-6 WYG and Amion Consulting, 2012 Avonmouth and Severnside Outline Development Strategy, 2012.

Ref. 9-7 UK Tourism Survey and International Passenger Survey (2010). South West of England Regional Summary. Visit England.

Ref. 9-8 Bristol Parks. A Management Plan for Blaise Castle Estate. 2008-2013. Bristol City Council.

Ref. 9-9 Visit England, 2010: Accessed November 2013: www.visitengland.org.

Seabank 3 PEI Report – Chapter 10 Traffic and Transport

May 2014 Page 10-1

10. Traffic and Transport

10.1. Introduction

10.1.1. This chapter of the PEI Report assesses the effect of the Proposed Development

and associated infrastructure on the surrounding highway network, public

transport, and local pedestrian and cyclist amenity. It is based on an assessment

of the interaction between future development related movements and existing

patterns of vehicular movements.

10.1.2. It sets out relevant Government policy at national and local level, which has been

considered in respect of the Proposed Development and associated

infrastructure. A description of the baseline conditions is provided, along with

details of the assessment methodology and significance criteria that have been

used to assess the potential effects.

10.1.3. The following effects on users of local roads and the occupiers and users of land

that front the roads have been assessed in this chapter in the following order:

• Severence;

• Driver delay;

• Pedestrian and cyclist delay;

• Pedestrian and cycle amenity;

• Public transport;

• Fear and intimidation; and

• Accidents and safety.

10.1.4. The traffic and transportation assessment is detailed further in a Transport

Assessment (TA), which is presented in Appendix E, Volume II of this PEI Report

and summarised in this chapter.

10.1.5. It has been agreed that a Construction Traffic Management Plan (CTMP) and a

construction workers’ Travel Plan will also be appended to the final ES, although

these have not been prepared as part of this PEI Report, as they will be finalised

following feedback received during the formal consultation process.

Consultation

10.1.6. Table 10-1 summarises the comments received from the HA, SGC and BCC in

their Scoping Responses and following their receipt of the URS ‘Trip Generation

and Distribution report’, which provided additional information on the proposed

methodology and approach for the TA (and which is an annex to the TA for

reference).


May 2014 Page 10-2

Table 10-1: Summary of Stakeholders Comments on Traffic and Transport

Consultee Key Issues / Comments Raised Location of Information in Chapter

BCC

The Applicant should consider the effect along the A403 from the Proposed Development Site to the M5, junction 18 including roundabouts.

This road link has been included in the TA and this chapter.

Methods of transport should be investigated for bringing materials to the Proposed Development Site, including rail or port.

See sections 10.3 and 10.5 of this chapter

Details of abnormal loads should be provided, as well as a before and after survey of the A403 in the vicinity of the Proposed Development Site in case it is damaged by the construction.

See sections 10.3 and 10.5 of this chapter for information on abnormal loads.

Before and after surveys will be discussed in the CTMP, which will be available as part of the final ES.

SGC The approach proposed is considered acceptable subject to including reference to relevant policies in the South Gloucestershire Local Plan and Core Strategy.

Reference to these policies is included in the TA.

The proposed development affects several promoted recreational routes identified under saved Local Plan policy LC12 Bridleway / Multiuser links.

Attention is required to the part of Ableton Lane that runs around the perimeter of the scrap yard by horses to reach the Minors Lane bridleway.

See section 10.6 of this chapter

Consideration should be given to other significant civil projects in the area that may have a bearing on the availability of workers, such as Hinckley Point and Oldbury Power Station.

See section 10.7.

Consideration within the TA should be made for materials to be brought to the site via rail and hence reducing the impact on the local highway network.


Consideration must be given to the local public rights of way for commuting.


A Travel Plan aiming to promote sustainable journeys, outlining all mitigation measures to the site is required. In addition to the Travel Plan, a Construction Traffic Management Plan is required.

Both a Travel Plan and a Construction Travel Plan will be submitted as part of the DCO application with the final ES.

HA Detailed information on staffing numbers, mode share, shift patterns, HGV numbers, HGV arrival/departure profiles, development phases, and Abnormal Indivisible Loads, should be determined at the earliest opportunity [for the construction phase].

See section 10.5 of this chapter and the TA.

The potential for cumulative impact with the potential Avon Power Station should be considered.



The ES should consider potential impacts on the local footpaths and any PROW.



May 2014 Page 10-3

Consultee Key Issues / Comments Raised Location of Information in Chapter

Potential transport impacts resulting from waste to be removed from the Site during construction should be addressed


As the delivery of the proposed new spine road is outside the control of the Applicant the ES should include an assessment of potential impacts should it not come forward as planned


10.1.7. Following receipt of the Scoping Opinion, a series of informal meetings were held

with SGC, BCC and HA in which it has been agreed that the construction phase

is the most critical phase of the development and the effects of the operational

phase may be scoped out of detailed further assessment.

10.1.8. This was agreed on the basis that once the Proposed Development is in

operation, it is estimated that up to a maximum of 40 workers will be present on

Site, which could be reduced to 22 new workers if the Proposed Development is

managed collaboratively alongside Seabank 1 & 2. A total of three shifts would

be in place resulting in an estimated maximum of 13 workers onsite at any one

time, including peak hours. Traffic associated with maintenance and deliveries (of

distillate fuel for example) will be minimal, with up to a maximum 24 two way daily

movements (12 deliveries) expected following a black start event; this is

expected to be an abnormal, infrequent event (e.g. once per annum).


10.1.9. There is no legislation or regulations specifically related to traffic and transport.

10.1.10. An overview of the national and local planning policy relevant to this assessment

is provided in the TA, Appendix E, Volume II of this PEI Report, as well as

Appendix D to Chapter 8: Planning Policy Context.



10.2.1. This assessment has been undertaken in accordance with the guidance provided

in the 1993 Institute of Environmental Assessment (IEA) publication Guidance

Notes No. 1: Guidelines for the Environmental Assessment of Road Traffic (Ref.

10-1), hereafter known as the IEMA guidelines.

10.2.2. The following categories of receptors that may be sensitive to changes in

numbers of people movements (sensitive receptors) have been identified:


May 2014 Page 10-4

• Severence - Severance is the perceived division that can occur within a

community when it becomes separated by a major traffic artery;

• Driver delay - Delays to non-development traffic can occur on the

network due to the additional traffic generated during site enabling and

construction;

• Pedestrian and cyclist delay - Changes in the volume, composition or

speed of traffic may affect the ability of people to cross roads and

therefore lead to greater increases in delay;

• Pedestrian and cycle amenity - Pedestrian and cyclist amenity is defined

as the relative pleasantness of a journey and is considered to be affected

by traffic flow, traffic composition and footway width/separation from

traffic;

• Public transport – The availability of public transport facilities and their

capacity in the area surrounding the Proposed Development Site;

• Fear and intimidation - The scale of fear and intimidation experienced by

pedestrians and cyclists is dependent on the volume of traffic, its HGV

composition, its proximity to people or the lack of protection caused by

factors such as narrow pavement widths; and

• Accidents and safety – The safety of the area is assessed by reviewing

the number of accidents taken place in the area as well as their nature.

10.2.3. The methodology for the TA which this chapter is based on has been agreed with

SGC, BCC and the HA and is outlined below.

Study Area and Data Sources

10.2.4. The scale and extent of the assessment has been defined whilst developing a

gravity model. The gravity model is a model which calculates the relationships

between two places, in this case between workers’ homes and the Proposed

Development Site, depending on travel distance, time and costs. The model has

been used to identify predicted construction workers’ journeys to and from the

Proposed Development Site. The geographical extent of the assessment is

illustrated in Figure 10-1 (Volume III of this PEI Report).

10.2.5. In order to establish traffic volumes on the local network, traffic surveys have

been undertaken. Two separate traffic count surveys were commissioned on the

A403 in November 2013. The details for these surveys are set out below and

also illustrated on Figure 10-1 (Volume III of this PEI Report):

• An Automatic Traffic Count (ATC) located on the A403 just north of the

entrance to the existing Seabank 1 & 2 site. Data was recorded for seven


May 2014 Page 10-5

days between Thursday 14 November and Wednesday 20 November

2013 (see Location 1 on Figure 10-1, Volume III of this PEI Report); and

• A classified traffic turning count survey at the junction Severn Road /

A403 / Chittening Road undertaken on Wednesday 14 November 2013 for

24 hours (see Location 2 on Figure 10-1, Volume III of this PEI Report).

10.2.6. A range of other existing traffic count data sources have been interrogated to

establish the baseline traffic in the surrounding area. In addition to the locations

where surveys were commissioned in November 2013, previous surveys have

also been completed at the locations set out below:

• Avonmouth Way / McLaren Road / King Road / A403 - Traffic counts

taken from the TA for the Viridor Resource Recovery Centre (Ref. 10-2)

by K&M on 24 February 2009 (see Location 3 on Figure 10-1, Volume III

of this PEI Report);

• A403 (near junction with B4064) towards the junctions with M48 – Data

derived from the Department for Transport’s (DfT’s) traffic count database

2012 (Ref. 10-3) (see Location 4 on Figure 10-1, Volume III of this PEI

Report); and

• Almondsbury Interchange Movement: (westbound), M4/M5, M4

(westbound) Slip to M5 (northbound – data derived from TRADS 2009

(Ref. 10-4) (see Location 5 on Figure 10-1, Volume III of this PEI Report).

10.2.7. The locations set out in Figure 10-1 (Volume III of this PEI Report) have been

selected for assessment. The criteria used for selecting these locations for

assessment is set out below.

• Locations 1 and 2: These survey locations have been selected because

they are close to the DCO Site and on the A403 which is expected to be

used by the construction traffic associated with the Proposed

Development and associated infrastructure ;

• Location 3: Based on the results of the trip distribution analysis it is

predicted that approximately 50-60% of construction workers are

expected to access the DCO Site from the north on the A403.

Consequently this location was included; and

• Locations 4 and 5: The HA, SGC and BCC advised that there may be

limited spare peak hour capacity at the Almondsbury Interchange

(M4/M5), as well as the junctions linking the A403 to the A4 and the M5.

These are junctions with high volumes of traffic, in particular during peak

hours. Location 4 and 5 have therefore been included in the assessment.


May 2014 Page 10-6

Estimated Construction Worker Numbers

10.2.8. To determine the number of construction workers expected to be required

throughout the construction phase, site specific construction requirements have

been estimated by a specialist potential contractor (who will be one of several

contractors that will be invited to tender for the construction works).

10.2.9. An example of the full construction schedule with associated activities is

presented in Table 5-1 in Chapter 5: Enabling Works and Construction. While this

schedule is inevitably only indicative at this stage, it nevertheless is based on

lessons learned from equivalent CCGT construction projects and therefore is

considered representative of the sort of construction programme that is likely to

occur. The numbers presented in the programme are considered to represent the

worst-case estimates of construction personnel accessing the Site, as it assumes

the Proposed Development would be built in a single phase, and the

assessments presented in this Chapter are therefore based on conservative

estimates.

10.2.10. Based on this information it is currently expected that the peak daily traffic

generation would occur in 2019, when an average of 790 staff may be accessing

the site daily. It was agreed with SGC, BCC and the HA that the expected peak

construction month should be the focus of the assessment.

10.2.11. It is the Applicant’s intention that the Order will allow a 7 year time period in

which to start construction after receipt of the DCO. The peak construction year

may therefore theoretically occur anywhere between 2017 and 2024. Given that

the majority of the cumulative schemes identified in Chapter 7: Assessment

Methodology are expected to be built and operational by 2017 (with the likely

exception of the Hinkey C Connection project and Avon Power Station), it is not

expected that the assessment of 2019 conditions is a limitation to the

assessment, or that a delay to the start of construction would affect the potential

effects or mitigation measures identified in this assessment.

10.2.12. For the future (2019) baseline, it has not been possible to determine the trip

distribution of all the cumulative schemes listed in Chapter 7: Assessment

Methodology from relevant Transport Assessments and their effect on various

junctions / road sections (the cumulative schemes are discussed further in the

last section of this chapter ‘Cumulative Effects Assessment’). To account for this,

relevant growth rates from the traffic model used in the assessment (TEMPro1)

has been applied to all baseline traffic data to forecast traffic flows for 2019. This

1 TEMPro (Trip End Model Presentation Program) is a software developed by the Department for Transport

and is used for transport planning purposes. The forecasts include population, employment, households by car

ownership, trip ends and simple traffic growth factors based on data from the National Transport Model (NTM).


May 2014 Page 10-7

will result in some double counting but it is considered a robust assumption for

this assessment.

10.2.13. As discussed in Chapter 7: Assessment Methodology, it is envisaged that the

proposed Spine Access Road will be available for use by the time the Proposed

Development is starting to be constructed; its construction is currently underway

and it is forecast for completion in early 2015. However, for the purposes of

presenting a conservative assessment of potential effects, this assessment has

been undertaken without including the benefits associated with this Spine Access

Road (which could relieve pressure on the A403).

10.2.14. It is therefore considered that an assessment of 2019 conditions without the

Spine Access Road represents a robust assessment for the purposes of this PEI

Report.


10.2.15. The significance of each effect is considered against the criteria within the IEMA

guidelines where possible. This guideline states that:

“for many effects there are no simple rules or formulae which define the

thresholds of significance and there is, therefore, a need for interpretation and

judgement on the part of the assessor, backed-up by data or quantified

information wherever possible. Such judgements will include the assessment

of the numbers of people experiencing a change in environmental impact as

well as the assessment of the damage to various natural resources.”

(paragraph 4.5)

10.2.16. According to the IEMA guidance, significance falls into two categories: not

significant and significant. The latter corresponds to likely significant effects in

accordance with the EIA regulations (and for the purpose of this PEI Report has

been assumed to correspond with moderate and major effects).

10.2.17. In the absence of established significance criteria for traffic and transport effects,

professional judgement has been used to assess whether the effects on traffic

and transport are considered to be significant, using the IEMA guidelines to

identify the scale and extent of the assessment to be undertaken.

10.2.18. The following rules are provided in the IEMA guidelines as a screening process

to define the scale and extent of a potential effect:

• Rule 1: Include roads where traffic flows are predicted to increase by

more than 30% (or where the numbers of HGVs are predicted to increase

by more than 30%); and


May 2014 Page 10-8

• Rule 2: Include any specifically sensitive areas (such as junctions with

limited capacity and residential areas) where traffic flows are predicted to

increase by 10% or more, or an absolute increase of 30 or more vehicles,

as defined by the HA. It should therefore be assumed that projected

changes in traffic of less than 10% or 30 vehicles create no discernible

environmental effect.

10.2.19. The IEMA guidelines elaborates on Rule 1 stating that projected changes in

traffic of less than 10% create no discernible environmental impact, given that

daily variations in background traffic flow may fluctuate by this amount, and that a

30% change in traffic flow represents a reasonable threshold for including a

highway link within the assessment.

10.2.20. This guidance is the only published guidance document to set out a methodology

for assessing potentially significant traffic-related environmental effects where a

proposed development is likely to give rise to changes in traffic flows.

10.2.21. After taking into consideration any mitigation measures, residual effects have

been identified as either:

• Adverse – meaning that they produce negative effects to transportation

and access;

• Negligible – meaning that there is no measurable effect; or

• Beneficial – meaning that they produce benefits in terms of transportation

and access.

10.2.22. Where adverse or beneficial effects have been identified these have been

assessed against the following scale:

• Minor – slight, very short or highly localised effect of no significant

consequence;

• Moderate – limited effect (by extent, duration or magnitude) which may be

considered significant; and

• Major – considerable effect (by extent, duration or magnitude) of more

than local significance or in breach of recognised acceptability, legislation,

policy or standards.




EIA Process.


May 2014 Page 10-9


under the Rochdale Envelope principle is an important consideration for this PEI

Report. However, in order to ensure a robust assessment has been undertaken,

the maximum parameters have been assessed. This includes the assumption

that the site levels will be raised up to the maximum 8.5m AOD, and that the

Proposed Development would be built in a single phase, which would compress

the construction worker numbers into a shorter time frame.

10.2.25. It is not considered that the flexibility in building location or heights and footprints

would have a material effect on the assessment.

10.2.26. It is intended the DCO Application will enable construction to start within 7 years

of receipt of the DCO. 2019 has been assessed for the peak construction year,

with 2021 as the year of first operation. As explained above, it is not expected

that a delay in the start date of construction would significantly affect the findings

of this assessment.


Local Road Network

10.3.1. The A403 Severn Road is the main route to the Proposed Development Site and

provides connections with the wider road network. It is a single lane carriageway

that runs from Avonmouth to the south of the proposed Development Site to a

junction with the M48 motorway in the north, located on the east side of the

Severn Bridge. To the south of the Proposed Development Site, the A403 links to

the A4 which continues towards the west and central Bristol, and also provides

access to Junctions 18 and 18a on the M5 and M49.

10.3.2. Due to the industrial nature of the surrounding area, the road network is designed

for HGV use. The speed limit on the A403 is mainly 50 miles per hour.

10.3.3. Based on discussions with the HA, SGC, and BCC, potentially sensitive areas on

the road network that may already experience high volumes of baseline traffic

include the roundabouts connecting the A403 with the A4 and the motorway

network, as well as the Almondsbury Interchange which connects the M4 with the

M5. It is understood that delays on these junctions could have a significant effect

on the surrounding road network.

Railway Services

10.3.4. The nearest railway station is Severn Beach train station which is located

approximately 2.7km from the Proposed Development Site, accessed via the

A403 Severn Road to the north. Services at Severn Beach are all terminating

services from Bristol Temple Meads. The journey between Severn Beach station


May 2014 Page 10-10

and Bristol Temple Meads is approximately 40 minutes and the frequency of the

train service is two trains between 0700 and 0800 in the morning and then one

train every two hours throughout the day.

10.3.5. A more frequent service is provided from Avonmouth Station, with services every

30 minutes during peak hours of the day. This station is further from the

Proposed Development Site, located approximately 6km to the south and just off

the A403 (St. Andrew’s Road).

10.3.6. The local trains accommodate spaces for bicycles, although some can only

accommodate two bicycles, on a first come first served basis.

10.3.7. The railway stations have limited facilities but are covered by CCTV and both

stations have access to a bus stop outside the station.

Local Bus Services

10.3.8. The bus stop nearest to the Proposed Development Site is located where Severn

Road meets with Ableton Lane in Severn Beach, approximately 2km north of the

entrance to the Proposed Development Site. The bus stop is served by route 625

and provides hourly services to University of West of England (UWE) via Easter

Compton, Cribbs Causeway, Patchway and Bristol Parkway in the southeast

direction, and to Severn Beach Station which is located further along the road in

the north direction. An extensive local and regional bus network can be reached

from Cribbs Causeway bus terminal.

10.3.9. Bus services are also provided from Avonmouth railway station, providing

connections to Shirehampton and Bristol City Centre (Route 41) every 20

minutes.

Walking and Cycling

10.3.10. Footways exist along the eastern side of the A403, for some sections. No street

lighting is provided along the Severn Road section of the A403. Due to the

distances between local transport facilities / residential areas and the Proposed

Development Site, the proportion of staff expected to walk to work in the local

area is not likely to be significant.

10.3.11. National Cycle Network route 41 runs adjacent to the A403, extending towards

Severn Village in the north and towards Avonmouth, Hallen and central Bristol in

the south.

10.3.12. The area of Severnside/ Avonmouth is well covered by public rights of ways,

footpaths, bridleways and byways, as shown in Figure 3-5, Volume III of this PEI

Report.


May 2014 Page 10-11

Site Access

10.3.13. This section discusses the existing access arrangements to the Proposed

Development Site and future baseline conditions, which assume the Spine

Access Road is in place.

10.3.14. These construction access points are illustrated in Figure 5-3, Volume III of this

PEI Report.

10.3.15. During construction a total of four access points may be utilised, although two of

these would not be available if the Spine Access Road is not built. The first

access point is located in the southeast corner of the Proposed Development

Site, from the existing roundabout that lies immediately east of the Site. An

additional two access points will be located further along the proposed Spine

Access Road that will link the aforementioned roundabout with the A403. A forth

access/egress point is along Ableton Lane, although this would be a secondary

access point and unlikely to be used by HGVs.

10.3.16. The access points for the operational Proposed Development are illustrated in

Figure 4-7, Volume III of this PEI Report.

10.3.17. The primary access point to the operational Site will be from the Spine Access

Road which is located immediately north of the Proposed Development Site, near

the eastern end of the Generating Station Site.

10.3.18. A secondary access point is proposed from the Seabank 1 & 2 site via an

entrance in the northwest corner of the Proposed Development Site. This access

will be used during operation to link the two sites, but would also act as a ‘back

up’ entrance should any issues occur with the Spine Access Road which is

currently not completed.

10.3.19. An additional secondary access point may also be included from Ableton Lane,

although it is not intended that this would be a main access point. It is likely that

this would be maintained for pedestrian access/egress and emergency vehicles.

Baseline Traffic flows

10.3.20. A summary of the traffic count results is provided in Plate 10-1 and Plate 10-2 for

the two traffic counts undertaken in November 2013. Plate 10-1 presents the

results for daily traffic flows on an average weekday and Plate 10-2 presents the

daily results for an average weekend.


May 2014 Page 10-12

Plate 10-1: Average Weekday Automatic Traffic Counts Results on the A403

10.3.21. There are pronounced peak hours during 07:00-08:00 and 17:00-18:00 during

the average weekday on the A403. HGV movements are generally consistent

throughout the day at approximately 100, with a slight increase between 07:00

and 17:00, peaking between 16:00-17:00.

Plate 10-2: Average Weekend Automatic Traffic Counts Results on the A403


May 2014 Page 10-13

10.3.22. Plate 10-2 shows a much lower volume and peak in traffic flows during the

weekends than weekdays. The weekend peak is approximately 300 vehicles,

occurring between 12:00 and 13:00. HGV movements remain at approximately

30 throughout the day.

10.3.23. Plate 10-3 illustrates the figures for daily flows on the junctions A403 / Severn

Road (A403) / Chittening Road on Wednesday 14 November 2013.

Plate 10-3: Traffic Counts Results at the Junction of Severn Road / A403 / Chittening

Road on Wednesday 14 November 2013

10.3.24. There are pronounced peak hours on the A403 at the Chittening Road junction

during the AM and PM peak periods of 07:00-09:00 and 17:00-18:00. HGV

movements are generally consistent throughout the day, ranging from

approximately 150 to 200, with its peak between 15:00-16:00. Turning counts

were not undertaken during weekends at this junction. However the results from

the ATC show that the volumes of traffic on the A403 are significantly less during

weekends.

Personal Injury Accidents

10.3.25. Personal Injury Accidents (PIAs) are road traffic accidents where either slight,

serious or fatal injuries to people have been recorded. The data includes

information such as the location of the accident, number of casualties, the modes

of travel involved, age and gender of those involved and the factors contributing

to the accident.


May 2014 Page 10-14

10.3.26. Data has been collected for the most recent five year period, 01 May 2008 to 30

April 2013 from BCC and SGC. Table 10-2 summaries the accidents at the key

road sections / junctions in the area. The reported incidents are of a type and

quantity that would be expected over a 5 year period, and notably only eight

incidents involved HGVs across the selected road sections / junctions. The

majority of accidents occurred at the Almondsbury Interchange.

10.3.27. A detailed review of the accident descriptions has taken place (additional

information is provided in the TA, Appendix E, Volume II of this PEI Report) and

all accidents have been results of driver error rather than any inherent highway

design issues.

Table 10-2: Personal Injury Accident Data (01 May 2008 to 30 April 2013)

Road Section / Junction Severity – Slight

Severity - Serious

Severity –

Fatal

Number of total

accidents

Including HGVs / LGVs

involved

A403 – between junction with Avonmouth Way (A4) and boarder with SGC

24 3 1 28 0

A403 – between boarder with BCC and junction with the M48

5 1 0 6 0

A403 intersecting with Avonmouth Road

4 2 0 6 0

A403 intersecting with Avonmouth Way

4 0 1 5 0

A403 intersecting with St Andrews Road

1 1 0 2 1 LGV

M49 / M5 8 2 0 10 0

Junction M48 / A403 4 1 0 5 0

Section between Almondsbury Interchange and junction M48 / A403

8 2 0 10

2 LGVs (Slight)

1 HGV (Serious)

Almondsbury Interchange 38 6 0 44 1 LGV (Slight)

7 HGVs (Slight)


10.4.1. There are no specific avoidance measures that have been implemented in the

design of the completed Proposed Development relevant to traffic and transport.

Chapter 5: Enabling Works and Construction does however note that the location

of the contractor compound is on the CCR Site, with the contractor parking

closest to the existing roundabout immediately east of the Proposed

Development Site.


May 2014 Page 10-15

10.4.2. The scheduled period of land raising has been determined based on preliminary

modelling, to derive the minimum acceptable period whilst avoiding significant

impacts to traffic and transport, air quality, and noise. It has been assumed that

the land raising period would be undertaken over a period of six months; this has

been calculated based on the maximum number of vehicle movements needed to

raise the site to 8.5m AOD distributed over the shortest time period deemed not

cause a significant impact. In reality, the land raising may be extended over a

longer period of time, which would reduce the effect on traffic and transport,

however it was considered prudent to present the worst-case scenario in this

assessment, which is considered to be 6 months.


Assessment of Construction Effects

10.5.1. The main construction activities include the site preparation and enabling works

phase and the construction of the Proposed Development; these activities are

discussed below.

Enabling Works

10.5.2. Chapter 13: Flood Risk, Hydrology and Water Resources of this PEI Report

identifies the need to raise the finished floor levels of the structures within the

Generating Station Site by an average of approximately 2.2m, from an average

current level of 6.3m AOD to a maximum 8.5m AOD.

10.5.3. To raise this land to a maximum 8.5m AOD, an estimated 158,000m3 of material

is required, which needs to be brought into the Proposed Development Site.

10.5.4. In reality, the amount of fill required may be up to 30% less than this, should the

cooling water system be bunded rather than raised for example, and when

allowing for a foundation sub-base for buildings. For the purpose of this

assessment however it has been considered robust to use the calculated

maximum value of 158,000m3.

10.5.5. The opportunities available to bring some of the material to Site by rail will be

explored by the Applicant following granting of the DCO, however it is not

currently considered viable. This is because access to rail facilities at the Site is

dependent on a third party development which has not yet proceeded (Ref. 10-5),

as well as it being unfeasible to extend the line into the Site for the construction

period only. For the purposes of the assessment presented in this PEI report

therefore, and to ensure a worst-case assessment of potential traffic impacts is

presented, it has been assumed that all material deliveries will be made by road.


May 2014 Page 10-16

10.5.6. Furthermore, there may be an opportunity to transport material via the

Avonmouth Port, although this would be subject to further discussions with the

port authority and the chosen contractor. In any event, any such material

imported through the port would have to be offloaded on to HGVs for

transportation to Site and these HGVs would have to travel via the A403. No

discussions with the Port Authority have therefore taken place at this stage, and

by assuming 100% road use at this stage, it should represent the worst case

scenario.

10.5.7. Until the Proposed Development has a DCO and the Applicant further

discussions with Contractors, it is not known where material for land raising will

be sourced from; it is considered most likely that material will be sourced from

local quarries. The nearest quarry with potentially suitable aggregates is

Stancombe Quarry in Flax Bourton, which would be accessed from the A370

south of Bristol via the A4 (Portway).

10.5.8. For the purpose of this assessment it is assumed that all HGVs delivering fill

would access the A403 from the A4 Portway. This is because the junctions

connecting the A403 with the A4 (Portway) and the motorway network have been

identified by the HA as potentially more sensitive than the junctions north of the

Proposed Development Site; hence this assumption is considered to represent

the worst-case scenario for the purposes of this PEI Report. Sensitivity tests have

been undertaken to assess the effect should this traffic be routed via other

directions.

10.5.9. In order to provide a robust assessment the assessment has been based on the

assumption that all deliveries would be 10m3 capacity HGVs. This would result in

up to 15,800 HGV deliveries being required to raise the Generating Station Site

to the maximum 8.5m AOD. In practice, it is expected that each HGV delivery

could transport 15m3 or more of top soil if using larger HGVs, which could in

practice reduce the number of deliveries required by around 5,300 HGVs.

10.5.10. As mentioned above, it has been assumed that the land raising period would be

undertaken over a period of six months and that work would be undertaken on

weekdays only and between 0700 and 1900 hours. The DCO Application

includes 24 hour deliveries, 7 days a week, and therefore in reality night-time and

weekend deliveries will be allowed which would reduce the pressure on the

daytime periods during weekdays. For robustness however, and in case the

Contractor chooses to avoid weekends and night-time delivers, it is assumed that

deliveries would be on weekdays only which would result in approximately 130

deliveries, or 260 two-way daily movements per day over the six month period.

10.5.11. Furthermore, in order to deliver a robust assessment that does not inadvertently

constrain the Contractor, it has been assumed that the material would be brought


May 2014 Page 10-17

in during a 10 hour period. On average over a 10 hour day, the daily two-way

movements would be approximately 26 movements per hour. As requested by

the HA, measures and/or commitments will be introduced to reduce the effect on

the highway network, such as limiting the number of deliveries during peak hours

and making use of areas within the Proposed Development Site to stockpile

material to avoid deliveries during holiday periods (when local road traffic flows

generally are higher). These measures will be detailed further in the CTMP,

which will be appended to the final ES.

10.5.12. During the enabling works it is assumed that up to 30 workers may access the

site daily. Some trips associated with these workers may occur during peak hours

although it is expected that the shift times would start and finish outside of the

peak hours identified above (0600 or 0700 start, 1900 finish).

10.5.13. An analysis of the potential change in traffic flows on the A403 at the junction

with Chittening Road / Severn Road (Location 2 on Figure 10-1, Volume III of this

PEI Report) and the signalised roundabout (Avonmouth Way / McLaren Road /

King Road / A403, (Location 3 on Figure 10-1, Volume III) is provided in Table

10-3. All traffic associated with the Proposed Development is assumed to pass

through both these locations, despite this being an unrealistic overestimate, in

order to present a conservative assessment as outlined above.

10.5.14. The results are presented for the peak hours prior to any HGV mitigation for both

junctions as well as daily flows for the A403 / Severn Road / Chittening Road

junction. Daily flows are not provided for the Avonmouth Way / McLaren Road /

King Road / A403 junction. Trips associated with the workers accessing the

Proposed Development Site during this phase have been excluded in the

assessment due to the low number discussed above.

Table 10-3: Traffic Increase during Land Raising Works Prior to Additional Mitigation

Location Time period

2019 Base Flows (Growthed to

include cumulative schemes)

Proposed Development Flows

during Land Raising (prior to

mitigation)

% increase (prior to mitigation)

Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

A403 / Severn Road / Chittering Road

(Location 2 on Figure 10-1 (Volume III)

AM Peak

(0800-0900) 437 124 26 26 6% 21%

PM Peak

(1700-1800) 371 115 26 26 7% 23%

Daily 11,128 2,927 260 260 2% 9%


May 2014 Page 10-18






mitigation)


Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

Avonmouth Way / McLaren Road / King Road / A403

(Location 3 on Figure 10-1 (Volume III)

AM Peak

(0800-0900) 1,996 638 26 26 1% 4%

PM Peak

(1700-1800) 1865 386 26 26 1% 7%

10.5.15. Table 10-3 demonstrates that the predicted maximum increase in percentage

HGVs during the land raise activity is predicted to be 21% in the morning peak

and 23% in the evening peak at the junction A403 / Severn Road / Chittening

Road. The increase in total vehicles at this junction is 6-7%, when taking into

account the large number of light vehicles using these roads.

10.5.16. It should be noted that this level of increase is calculated based on a number of

conservative assumptions outlined above and without assuming any

interventions/mitigation measures, which are discussed later in this chapter.

10.5.17. Despite the conservative assumptions applied to this assessment, the magnitude

of change shown is less than the 30% threshold noted by IEMA for requiring

further consideration. The level of change anticipated is considered to be

negligible.

10.5.18. Furthermore, given the general absence of residential areas along the A403, the

area is not considered sensitive to this level of traffic increase. The residential

settlement of Avonmouth is located south of the roundabout Avonmouth Way /

McLaren Road / King Road / A403. Other nearby residential areas includes

Lawrence Weston, Hallen and Severn Beach. However, the A403 does not run

through any residential settlements.

10.5.19. Sensitivity tests have been undertaken to establish the effect should the HGVs

be routed via the M5 through Junction 19 to the A4 (Location 6 on Figure 10-1,

Volume III of this PEI Report) or via the M48 (Location 4 on Figure 10-1, Volume

III of this PEI Report). The results of these tests are presented in Table 10-4.


May 2014 Page 10-19

Table 10-4: Traffic Increase during Land Raising Prior to Additional Mitigation – Sensitivity Test






mitigation)


Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

Traffic towards the A4 from the M5 (north)

Location 6 on Figure 10-1 (Volume III)

AM Peak

(0800-0900) 1,833 338 13 13 1% 4%

PM Peak

(1700-1800) 1,128 363 13 13 1% 4%

Daily 15,726 3,403 130 130 1% 4%

A403 - between B4055 and M48

Location 4 on Figure 10-1 (Volume III)

AM Peak

(0800-0900) 617 96 26 26 4% 27%

PM Peak

(1700-1800) 694 97 26 26 4% 27%

Daily 7,981 1,603 260 260 3% 16%

10.5.20. The HGV increases for this location are 4% for both peaks as well as for daily

flows. For the final sensitivity test, significantly less base flows is seen at this

location compared to the junctions south of the Proposed Development Site and

therefore a higher percentage increase is expected (a 27% increase in HGVs

during peak hours). However, the overall traffic figures are significantly lower for

all scenarios.

Construction Phase

10.5.21. The peak month of construction activity (in terms of traffic generation) is expected

to occur in month 25 of the construction schedule (see Chapter 5: Enabling

Works and Construction), which is currently envisaged to be 2019. Activities likely

to be taking place during this period include the construction of the main plant

buildings, water demineralising treatment plant, gas pressure reducing station,

pipe bridges and cable racking.

10.5.22. The required workforce during the construction period is expected to reach a

peak of approximately 790 construction workers onsite in 2019. This estimate

has been obtained from one of the potential contractors who is likely to be invited

to bid for the construction works and is therefore considered a reasoned

estimation of worker numbers onsite.


May 2014 Page 10-20

10.5.23. An additional 100 staff are expected to be required to construct the associated

infrastructure, which mainly comprises the proposed cooling water pipeline and

electricity cables, but it is not expected that this will correspond with the peak

month of construction onsite; the cooling water pipeline will be constructed in

2020 and 2021 based on the current programme. Hence, realistically 790

workers are expected to represent the estimated maximum number of workers on

the project in any one month.

10.5.24. Prior to any intervention or management of worker trips, a car/van occupancy

rate of 1.35 has been adopted, resulting in approximately 585 vehicles accessing

the Proposed Development Site daily, if it is conservatively assumed that none of

the workforce travel to Site by other modes. This is the equivalent to 1,171 two

way trips. The car occupancy rate of 1.35 is generally accepted in the

construction industry and indeed a figure that has been used and accepted in the

assessment of other proposals involving the construction of power stations.

10.5.25. A gravity model has been developed to estimate where construction worker

vehicles may travel from and define their route to the Proposed Development

Site. Using employment data from the Office of National Statistics (Ref. 10-6), as

shown in Appendix E, Volume II of this PEI Report, a distribution profile has been

developed based on the number of residents working in the construction sector in

each local authority within defined catchment areas as outlined in this chapter.

10.5.26. The results indicate that a total of 511 vehicles (44%) are expected to access the

Proposed Development Site from the south along the A403 via the A4 and

Hallen, and 660 (56%) are expected to access the Proposed Development Site

from the north via the M48 Junction 1. These figures are expected to reduce

following the introduction of travel plan measures such as shuttle bus services

and car sharing schemes, which are discussed further later in this chapter.

10.5.27. In terms of HGVs, the maximum volume of HGVs on the network is estimated to

peak at 80 two way daily vehicle movements (40 in and 40 out). It is anticipated

that this peak period is likely to also occur within 2019. Outside of this period the

number of two way HGV movements will be an estimated 40 per day (20 in and

20 out).

10.5.28. An assumption that has been applied to the HGV trip distribution during the

construction phase is an even distribution across the network. This is an

approach that has been applied in other Transport Assessments for CCGT power

stations (Ref. 10-7) on the basis that it is not known where material will be

sourced from at this stage. In the case for the Proposed Development Site, it is

therefore assumed that 50% of all HGVs will arrive from north via the M48 and

50% from the south via the A4. Construction material such as steelwork will be

sourced from local suppliers in the Avonmouth / Severnside area where possible;


May 2014 Page 10-21

the Applicant would propose hosting a series of ‘Meet-the-Buyer’ events to

encourage and identify potential local suppliers.

10.5.29. For the peak hour assessments, the assumptions include:

• The total daily HGV trips are distributed evenly across a 10 hour working

day between 0800 and 1800 Monday to Friday (this is worst-case

designed to coincide with AM and PM peak hour. In reality deliveries will

be allowed 24 hours, 7 days a week and would be schedule to avoid

arrivals in peak hours);

• All HGV trips / deliveries will arrive and depart within the same hour;

• An arrival and departure profile based on other similar sites has been

applied to the construction workers to establish the effects on the road

network during peak hours.

10.5.30. The above has been applied to the assessment to provide a worst-case scenario.

10.5.31. Table 10-5 presents the predicted increase on the local road network during the

main construction works. Daily flows are not provided for the Avonmouth Way /

McLaren Road / King Road / A403 junction and the M4 / M5 to M4 movement on

the Almondsbury Interchange.

Table 10-5: Traffic Increase during Main Construction Works Prior to Additional Mitigation

Road Section / Junction

Time period

2019 base (Growthed traffic flows with

committed developments)

Proposed Development Flows during Construction (prior to mitigation)


Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

A403 just north of junction with existing Seabank access

(Location 1 on Figure 10-1 (Volume III))

AM Peak (0800-0900) 671 125 93 4 14% 3%

PM Peak (1700-1800) 839 112 75 4 9% 4%

Daily 9,905 2,201 551 40 6% 2%

A403 / Severn Road (A403) / Chittening Road


AM Peak (0800-0900)

439 124 93 4 21% 3%

PM Peak (1700-1800)

372 115 75 4 20% 3%

Daily 11338 2982 551 40 5% 1%


May 2014 Page 10-22


Time period

2019 base (Growthed traffic flows with

committed developments)

Proposed Development Flows during Construction (prior to mitigation)


Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

A403 (south of junction with M48)


AM Peak (0800-0900)

627 98 120 4 19% 4%

PM Peak (1700-1800)

709 99 96 4 14% 4%

Daily 8157 1638 700 40 9% 2%



AM Peak (0800-0900)

2090 666 56 4 3% 1%

PM Peak (1700-1800)

1986 407 46 4 2% 1%

Almondsbury Interchange Movement: Southbound, M4/M5, M5 Southbound slip to M4 Westbound


AM Peak (0800-0900)

238 24 38 1 16% 4%

PM Peak (1700-1800)

301 42 1 1 0% 2%

10.5.32. Table 10-5 shows percentage increases for total vehicle flows during peak hours

of up to 21% predicted along the A403 if no mitigation measures (interventions)

are introduced; the higher increases are partly a reflection of the low baseline

flows however. The total daily increases are significantly lower (between 5% and

9%) at these locations and this suggests that there will be opportunities to

manage movements to reduce these effect during peak hours through the

implementation of a CTMP.

10.5.33. It should be noted that for the traffic effect on the Almondsbury Interchange

(Location 5), only one movement has been assessed reflecting the likely use of

this junction to access the Site, from M5 southbound to M4 westbound.


May 2014 Page 10-23

10.5.34. As mentioned above, it is likely that the increases presented above are an

overestimate of the actual effect on local traffic flows; in particular, most supliers

of materials will deliberately aim to avoid peak hours. Despite these conservative

assumptions, it is considered that the predicted increase in traffic flow outlined in

Table 10-5 is negligible.

Severance

10.5.35. Severance is the perceived division that can occur within a community when it

becomes separated by a major traffic artery. It may result from the difficulty of

crossing a heavily trafficked existing road for example, or as a result of a physical

barrier created by the road itself.

10.5.36. There are no predictive formulae which give simple relationships between traffic

factors and levels of severance. As detailed above, IEMA guidelines suggest that

only changes in traffic flows of 30% or more are likely to produce changes in

severance on the road network. This threshold is unlikely to be exceeded by

traffic generated by the Proposed Development and associated infrastructure.

Furthermore, given the observed pedestrian and cyclist activity along the study

roads it is considered unlikely that such temporary increases in traffic during

enabling works and the construction phase would result in difficulties for people

to cross the A403.

10.5.37. The predicted increase in total vehicles is expected to be approximately four

vehicles during peak hours along the A403. Furthermore, the implementation of

the CTMP (which will be produced for the final ES) should help site deliveries to

be co-ordinated and managed to minimise disruption to local residents and other

highway users. Therefore the effect of severance during all phases of the

Proposed Development is considered to be negligible.

Driver Delay

10.5.38. Delays to non-development traffic can occur on the network due to the additional

traffic generated during site enabling and construction. The IEMA guidelines note

that these additional delays are only likely to be significant when the traffic on the

network in the study area is already at, or close to, the capacity of the system.

10.5.39. From discussions with SGC, BCC and the HA, it is apparent that there are a

number of junctions where there is limited spare capacity. The junctions identified

are the Almondsbury interchange (junction of M5 and M4) and the A4/A403

signalised roundabout, where junction performance is sensitive to increases in

the number of HGVs.

10.5.40. Driver delay during the peak construction month is not likely to be experienced at

the key junctions on the highway network associated with an increase between


May 2014 Page 10-24

1% and 4% of HGVs. Therefore the effect of driver delay during the peak month

of traffic generation is considered to be negligible. The effect during other

months and activities is expected to be less and therefore also negligible.

Some driver delay may also occur as a result of the construction of the proposed

cooling water pipeline, although this will be temporary, as it is expected to take a

only few days to trench the pipeline across the affected roads and backfill it. The

affected roads are illustrated in Figure 10-2 (Volume III of this PEI Report).

10.5.41. To minimise delays as far as possible, works will be scheduled during quieter

periods such as weekends where possible and outside of peak hours. To mitigate

significant diversions due to a complete closure of the roads, the pipeline

construction will be staged so that, where ever possible, one lane can be

maintained open, and where necessary, such as at the A403 temporary traffic

lights, the lanes temporarily reinstated to allow access on both lanes during peak

hours.

10.5.42. Taking into account the mitigation measures suggested above and their

temporary nature of this interruption, the effect of the pipeline construction on

driver delay is expected to be negligible.

Abnormal Loads

10.5.43. In addition to the typical HGV deliveries, the delivery of abnormal loads may

result in temporary localised delays which can be managed by implementing the

CTMP. An “abnormal indivisible load” is a load that due to its length, width or

weight cannot be carried without undue expense or risk of damage. These

deliveries therefore require notifications to relevant authorities before being

authorised. The estimated plant type and equipment during Construction

Activities are outlined in in Table 5-2, Chapter 5: Enabling Works and

Construction of this PEI Report.

10.5.44. The CTMP would address temporary road signage requirements, construction

traffic routing and timing. There are anticipated to be only up to 20-30 abnormal

load deliveries during the 37 month construction period (following enabling

works), corresponding with less than 1 a month on average. Delays from

abnormal loads are therefore considered to be negligible.

Pedestrian and Cyclist Delay

10.5.45. Changes in the volume, composition or speed of traffic may affect the ability of

people to cross roads and use them for cycling. There are also potential

pedestrian and cyclist delay should diversion routes be required during the

construction of the proposed cooling water pipeline. In general terms, increases

in traffic levels are likely to lead to greater increases in delay. However, given the


May 2014 Page 10-25

range of local factors and conditions which can influence pedestrian and cyclist

delay, IEMA does not recommend that thresholds be used as a means to

establish the significance of pedestrian and cyclist delay.

10.5.46. Onsite observations by URS indicated that there is minimal pedestrian and cyclist

activity along the A403. As detailed above, the expected increase even in the

morning peak on a weekday is unlikely to result in difficulties for people to cross

the A403.

10.5.47. Part of the proposed cooling water pipeline corridor runs parallel to an existing

cycle path between Moorend Farm Avenue and the access to the A403, contains

part of a cycle path in the vicinity of the railway, and crosses a cyclepath on

Severn Road. This will require temporary closures to these cycle paths during the

period of works, although a diversionary route will be established and agreed with

BCC in advance of these works commencing.

10.5.48. Taking these factors into consideration, the effect of development generated

traffic on pedestrian and cyclist delay is considered to be negligible.

Pedestrian and Cyclist Amenity

10.5.49. Pedestrian and cyclist amenity is broadly defined as the relative pleasantness of

a journey and is considered to be affected by traffic flow, traffic composition, and

footway width/separation from traffic. The IEMA guidelines note that changes in

pedestrian and cyclist amenity may be considered to be significant where the

traffic flow (or its HGV component) is halved or doubled as a result of

development activity.

10.5.50. As detailed above, taking into account minimal pedestrian and cyclist activity, the

increase in traffic along the A403 is unlikely to affect the pleasantness of

pedestrian and cyclist journeys along the A403. Therefore, the effect of

development related traffic on pedestrian and cyclist amenity is considered to be

negligible.

10.5.51. The construction of the proposed cooling water pipeline will affect some sections

of the PROW and cycle routes, as well as needing to cross beneath the Severn

Beach railway line. Where possible access will be maintained for pedestrians and

cyclists. If at some locations this is not possible, then prior closure notice will be

given and alternative routes identified and signposted. Prior closure notices

normally required 12 weeks of advertising prior to event / closure / diversion.

Given the temporary nature of these closures and the relative low number of

users, these closures are not anticipated to cause a significant impact to

pedestrian and cyclist amenity.


May 2014 Page 10-26

10.5.52. As part of the operational Proposed Development, the Applicant is committed to

improving the local PROW network and is proposing to create a new PROW from

Ableton Lane within the Proposed Development Site, around the southern

boundary of the CCR Site and connecting to the existing roundabout on the

Spine Access Road to the east of the Site. This will increase the permeability of

the area and also provide improved foot and cycle access to and from the

Proposed Development Site to the A403. This additional permeability of the area

is considered a minor beneficial effect on pedestrian and cyclist amenity.

Public Transport

10.5.53. Potential effects on the bus and rail network of additional patronage could

include:

• Crowding on buses and trains;

• Congestion at bus stops and stations; and

• Congestion on footpaths on routes to bus stops and stations.

10.5.54. The construction workers’ Travel Plan will aim to encourage workers to use public

transport as far as is practical. It is anticipated that sufficient capacity is available

on the existing services as the majority of workers would use services outside of

peak hours where possible due shift staring / finishing times.

10.5.55. Given the variety of public transport options available in the area, combined with

the likelihood that most workers will arrive to site by car, the effect on public

transport services of the construction phase of the Proposed Development Site

and associated infrastructure is expected to be negligible.

Fear and Intimidation

10.5.56. The scale of fear and intimidation experienced by pedestrians and cyclists is

dependent on the volume of traffic, its HGV composition, its proximity to people

or the lack of protection caused by factors such as narrow pavement widths.

However, there are no commonly agreed thresholds by which to determine the

significance of the effect.

10.5.57. The highest estimated percentage increase in HGV traffic resulting from

construction is 21% during peak hour. However, the level of pedestrian and

cyclist activity along the A403 up to the proposed access points is considered

minimal. This also only reflects a 6-7% increase in total flows, and is based on a

series of conservative assumptions that are likely to have overestimated the trip

generation.


May 2014 Page 10-27

10.5.58. A CTMP will be produced for the final ES that considers construction traffic routes

and timings of traffic movements (e.g. to reduce the risk of vehicles convoying),

to be agreed with the HA, SGC and BCC. Following implementation of the CTMP

it is considered that the scale of fear and intimidation experienced by pedestrians

and cyclist would be negligible.

Accidents and Safety

10.5.59. Due to the numerous local causation factors involved in Personal Injury

Accidents, the IEMA guidelines do not recommend the use of thresholds to

determine significance.

10.5.60. Given that construction is temporary, the changes predicted are temporary, and

the estimated hourly traffic generation is relatively low to the total flows on the

roads. It is therefore considered unlikely that there would be an impact upon road

safety and accident levels due to Proposed Development traffic. As described

earlier in this chapter, the A403 is not considered to be an accident problem area.

10.5.61. The potential effects of abnormal loads on highway safety are considered to be

not significant, given that they will be relatively few in number and will be

managed through appropriate traffic management procedures and following

notification of the appropriate authorities. Furthermore, all abnormal loads will be

escorted and the movement of these vehicles will be programmed to avoid busy

periods.

10.5.62. A potential effect on highway safety relates to the transfer of dirt and debris from

the Proposed Development Site onto the carriageway. Mitigation measures to

minimise this effect are outlined further detail in Chapter 11: Air Quality.

10.5.63. In conclusion, the risk of accidents is considered to be negligible, prior to the

implementation of any mitigation measures.

Assessment of Operational Effects

10.5.64. As agreed with SGC, BCC and the HA, the operational phase has been scoped

out of the traffic and transport assessment. The operational Proposed

Development is estimated to require up to 40 workers on site over three 8 hour

shifts per day (i.e. approximately 13 staff at any one time onsite). This may be

reduced further if the site is managed collaboratively along with Seabank 1 & 2.

10.5.65. Traffic associated with maintenance and deliveries (distillate fuel deliveries for

example) will be minimal, with up to a maximum 24 daily movements (12

deliveries) expected following a black start event (which is likely to be an

infrequent event, perhaps only once per year). It is also expected that these

deliveries would be distributed over a period of several days.


May 2014 Page 10-28

10.5.66. The effect of traffic flows during operation is therefore predicted to be negligible.

10.5.67. As identified above, the delivery of a new PROW is anticipated to lead to a minor

beneficial effect on pedestrian and cyclist amenity.

Assessment of Decommissioning Effects

10.5.68. It is envisaged that the plant will have a design life of 30 years, with an operating

life possibly beyond this. It is not possible to accurately predict the

decommissioning traffic flows and junction capacities at this point in the future,

however it is anticipated that there would be far fewer vehicle and workers

numbers during decommissioning than in construction. It is also expected that

decommissioning would be relatively short in comparison to the construction

period and therefore only a short-term, temporary effect.

10.5.69. The significance of the effect of decommissioning traffic is therefore anticipated

to be negligible.

Mitigation Measures

10.5.70. The mitigation measures considered for the Proposed Development and

associated infrastructure is principally targeted at reducing cumulative effects.

10.5.71. A CTMP will be produced to accompany the DCO Application to manage HGV

and worker movements associated with the Proposed Development. The plan will

aim to ensure that the number of HGV movements is reduced as far as possible

during periods when traffic on the surrounding road network is busy. This

includes peak hour and shoulder peaks, school holiday times and bank holiday

weekends. Any access route restrictions, where these may be deemed

necessary, will be included in the CTMP.

10.5.72. Storage areas will be provided onsite so night-time and weekends deliveries can

be maximised as far as possible. The noise effects associated with this are

assessed in Chapter 12: Noise and Vibration. This will also apply to the land

raising work during the enabling works phase.

10.5.73. The key mitigation measures likely to be included in the CTMP include:

• Promoting public transport by introducing shuttle bus services between

the DCO Site and Avonmouth Railway station and Bristol Parkway

Railway station (not for public use);

• Introducing a car sharing scheme to increase the car occupancy rate; and

• Promoting cycling, although due to the location of the DCO Site in relation

to the worker catchment area cycling as a mode a transport is likely to be

limited to a very small proportion of staff.


May 2014 Page 10-29

10.5.74. These mitigation measures are required to mitigate cumulative effects rather than

the effect of the Proposed Development in isolation (which is negligible); however

such measures in the Travel Plan would be expected to reduce the number of

vehicles on the highway network during peak times associated with the Proposed

Development and are therefore discussed here. The figures have been derived

from a model presented in further detail in the TA. The results are presented in

Table 10-6.

Table 10-6: Predicted Increase during Construction Phase following Mitigation Measures


Time period

2019 Base (Growthed traffic

flows with committed

developments)

Proposed Development Flows during construction

(after mitigation)

% increase

(after mitigation)

Total Vehicles

HGVs Total

Vehicles HGVs

Total Vehicles

HGVs

A403 just north of junction with existing Seabank access


AM Peak (0800-0900)

671 125 53 4 8% 3%

PM Peak (1700-1800)

839 112 43 4 5% 4%

Daily 9,905 2,201 320 40 3% 2%



AM Peak (0800-0900)

439 124 53 4 12% 3%

PM Peak (1700-1800)

372 115 43 4 12% 3%

Daily 11,338 2,982 320 40 3% 1%

A403 (south of junction with M48)


AM Peak (0800-0900)

627 98 74 4 12% 4%

PM Peak (1700-1800)

709 99 60 4 8% 4%

Daily 8,157 1,638 439 40 5% 2%



AM Peak (0800-0900)

2,090 666 33 4 2% 1%

PM Peak (1700-1800)

1,986 407 27 4 1% 1%

Almondsbury Interchange Movement: SB, M4/M5, M5 Southbound slip to M4 Westbound


AM Peak (0800-0900)

238 24 18 1 8% 4%

PM Peak (1700-1800)

301 42 1 1 0% 2%


May 2014 Page 10-30

10.5.75. Table 10-6 shows the predicted effect on the highway network following the

potential introduction of the mitigation measures. An increase of 12% is expected

in the AM and PM peak on the junction A403 / Severn Road (403) / Chittening

Road (south of proposed access points) and in the AM peak on the A403 towards

the junctions with M48. This is a reduction of between 7% and 9% compared to

the scenario where no mitigation measures have been introduced. Similarly, a

significant reduction is expected on the junction A403 / Severn Road (A403) /

Chittening Road, following the introduction of Travel Plan measures.


10.6.1. Despite the combination of conservative assumptions assumed in this

assessment, there are not predicted to be any residual traffic and transport

effects associated with the Proposed Development and associated infrastructure.

10.6.2. Table 10-7 summaries the residual effects during the peak month of the main

construction phase as this represents the worst-case scenario; despite this the

predicted effect is negligible, with the exception of pedestrian and cyclist

amenity which would be minor beneficial because of the proposed provision of

a new PROW. The predicted effect during the remainder of the enabling works,

construction, operational and decommission phases is expected to be less than

this and therefore also negligible.


Potential Effect Mitigation Measures Significance of the Residual Effect

Severance n/a Negligible

Driver Delay Travel Plan measures such as a Shuttle bus services car sharing schemes

Negligible

Pedestrian and Cyclist Delay

n/a Negligible

Pedestrian and Cyclist Amenity

Provision of new PROW Minor beneficial

Fear and intimidation n/a Negligible

Accident and Safety Avoid peak and busy periods where possible. Abnormal loads to be escorted.

Negligible


10.7.1. A significant number of other schemes are either being developed or planned in

the area. The future baseline is calculated for 2019 as this year is expected to


May 2014 Page 10-31

experience the month with the highest demand for personnel accessing the

Proposed Development Site during the construction phase.

10.7.2. Transport studies and assessments published for committed nearby

developments have been reviewed and considered for the cumulative effect.

Based on this review it is considered reasonable to assume that all the

cumulative schemes outlined in Chapter 7: Assessment Methodology would be in

operation by 2019, with the exception of Avon Power Station for which an

application has not yet been submitted and Hinkley C Connection Project.

10.7.3. As mentioned above, these cumulative schemes have been included within the

future, 2019 baseline, as well as a growth factor that may have double counted

the effect of some schemes. The predicted effect of Avon Power Station has

been excluded from the assessment because of the uncertainty associated with

this development and whether it will proceed and when. It is expected the

operational traffic associated with Avon Power Station would be of similar scale

to the Proposed Development, with approximately 10 staff expected during each

shift, which should therefore not give rise to any significant cumulative effects

when considered along with the Proposed Development and other schemes in

the area. Should the construction phase overlap with the Proposed Development,

it is envisaged that the Contractors for each development would liaise with one

another to minimise the number of trips during peak hours and disruption to the

local communities. Any application for the Avon Power Station scheme is likely to

be subsequent to the DCO Application for the Proposed Development however,

and therefore a rigorous assessment of cumulative effects during the

construction period would be expected to be undertaken by the Applicant for that

scheme.

10.7.4. The HA and transport officers at SGC and BCC have also raised concerns

regarding the potential transport effect of the construction of Hinkley Point C

nuclear power station; this is a proposed development for a new 3,200MW two

reactor nuclear power station near Bridgwater, Somerset, which is likely to be

under construction in 2019 (pending discharge of conditions). Through

communications with the Hinkley Development Management at West Somerset

Council as well as the Transport Coordinator from the Applicant, it is understood

that Hinkley Point C is expected to complete commissioning of the first unit in

2023, which would mean that the peak construction might occur in 2018.

However, these dates cannot be confirmed at this stage as the financial

commitments have yet to be made. Furthermore, no trip distribution analysis is

available beyond Junction 23 and 24 on the M5 within the study area to allow the

consideration of cumulative effects with the catchment of the Proposed

Development. As the predicted effect of the Proposed Development has been

shown to be negligible, it therefore should not contribute to any cumulative


May 2014 Page 10-32

effects with Hinkley Point C. It has therefore not been deemed necessary to

assess this scheme further.

10.7.5. In addition, the Hinkley C Connection Project, which is the construction of OHL

from Hinkley C to Seabank Substation and upgrade works at the substation, is

predicted to have a negligible effect on the A403 and other study roads

considered in this assessment. There is not considered to be any potential for

significant cumulative effects therefore arising from the overlap in construction

period between this scheme and the Proposed Development; this will be

reviewed following the submission of the DCO Application for the Hinkley C

Connection Project (expected in Spring 2014).

10.7.6. Table 10-8 presents a summary of the cumulative effects along the A403,

comparing the following scenarios:

• 2013 baseline flows;

• 2019 flows, including background growth and cumulative traffic; and

• 2019 with background growth and cumulative traffic along with peak

construction traffic associated with the Proposed Development.

Table 10-8: Predicted Cumulative Effects (Total Traffic including HGVs)


Time period 2013

Baseline

2019 Baseline

(incl. cumulative schemes)

Increase from 2013

(due to cumulative schemes)

2019 (incl. cumulative schemes) + Proposed

Development (with

mitigation)

Increase from 2013

(due to Proposed

Development and

cumulative schemes)

A403 just north of junction with existing Seabank 1 & 2 access

(Location 1 on Figure 10-1)

AM Peak (0800-0900)

623 671 7.7% 724 16.2%

PM Peak (1700-1800)

777 839 8.0% 882 13.5%

Daily

9,270 9,905 6.9% 10,225 10.3%


(Location 2 on Figure 10-1)

AM Peak (0800-

0900)

359 439 22.2% 492 37.0%

PM Peak (1700-1800)

304 372 22.4% 415 36.5%

Daily

10,611 11,338 6.9% 11,658 9.9%


May 2014 Page 10-33

10.7.7. The cumulative schemes are predicted to increase traffic flows by approximately

7% to 8% along the A403 just north of the existing junction with Seabank 1 & 2.

The daily increase along A403 / Severn Road (A403) / Chittening Road is

approximately 7% due to these other schemes, although increases to

approximately 22% during the AM and PM peak hours.

10.7.8. When also considering the construction traffic associated with the Proposed

Development, and comparing this against 2013 baseline traffic flows, the daily

increase is in the order of 8-9% along these road links. The effect during peak

hours is larger and is shown to be 16.2% and 13.5% for the AM and PM peak

respectively along the A403 just north of the existing junction with Seabank 1 & 2.

The change along A403 / Severn Road (A403) / Chittening Road is 37.0% during

both peak hours.

10.7.9. The magnitude of change exceeds the 30% threshold suggested by IEMA for

peak hours, however as discussed above the assessment has incorporated a

number of conservative assumptions (which may have led to double counting of

the cumulative schemes) and most importantly, it has been based on the peak

month of construction. The rest of the construction period is expected to lead to

less traffic and deliveries are likely to be timed deliberately to avoid these peak

hours. Any minor adverse effect therefore that may be predicted is expected to

be short-term, with the majority of the construction period negligible.

10.7.10. The cumulative effects during operation are expected to be much less and

therefore negligible.



design or anticipated peak year of construction may be subject to change prior to

submission of the final DCO application. Any changes that lead to differing or

new impacts and effects will be highlighted within the final ES, along with the

reasons for the change.

10.8.2. It is also likely that the baseline conditions will change between the preparation of

this PEI Report and the final ES. The Proposed Development Site is currently

subject to excavation, top soil stripping, and levelling in certain areas in order for

third parties to deliver the Spine Access Road and new channel for the Red

Rhine, which are discussed in Chapter 2: The DCO and EIA Process and

Chapter 7: Assessment Methodology. A haul road is also being constructed

through the middle of the Proposed Development Site to enable access by third

party from the roundabout to the east of the Site to the Severnside Energy

Recovery Centre to the west. These works onsite are being undertaken by other


May 2014 Page 10-34

developers, under extant planning permissions and are separate to the Proposed

Development.


of submission, or an agreed point of time shortly before, as well as any changed



10.8.4. The list of cumulative schemes that require consideration in the cumulative effect

assessment is also dynamic and subject to change. The final ES will take

account of changes to the status and nature of these schemes. The aspirational

M49 junction development may also need to be considered if the Planning

Inspectorate is formally notified that it should expect a DCO Application in the

near future.

10.8.5. A CTMP and a construction Travel Plan have not been prepared as part of this

PEI Report but will be appended to the final ES. Where applicable, the findings of

these reports will be summarised in the final ES chapter.

10.8.6. It is anticipated that a detailed assessment of traffic increases on the A4

signalised roundabouts will be included in the final ES and TA, along with

capacity analysis for the following roads and junctions:

• Merge diverge assessment at M48 junction 1;

• A403 Smoke Lane/Poplar Way West priority roundabout;

• A403 St Andrew’s Road/Kings Weston Lane (signalised junction);

• A403 St Andrew’s Road/St George’s Industrial Estate;

• A403/Redwick Road in Pilning; and

• A403 Chittening Road / Severn Road.

10.9. References

Ref 10-1 Institute of Environmental Assessment (IEA) (1993) Guidance Notes

No. 1: Guidelines for the Environmental Assessment of Road Traffic

Ref 10-2 Viridor. Transport Assessment for Viridor Resource Recovery Centre,

Ref 10-3 Department for Transport (DfT) AADF (Annual Average Data Flow)

Database

Ref 10-4 Highways Agency, TRADS database

Ref 10-5 SITA (2012) Environmental Statement Volume 4; Non0Technical

Summary (April 2012) Bottom Ash Recycling Facility & Railhead


May 2014 Page 10-35

Ref 10-6 Office for National Statistics. Nomis Data ‘Annual business inquiry

employee analysis SIC’

Ref 10-7 Transport Assessment for Killingholme Power Station, Drakelow CCGT

Power Station and High Marnham CCGT Power Station

Seabank 3 PEI Report – Chapter 11 Air Quality

May 2014 Page 11-1

11. Air Quality

11.1. Introduction

11.1.1. The purpose of this chapter is to assess the potential effects of emissions to air

resulting from the construction and operation of the Proposed Development.

11.1.2. It describes the assessment methodology, the baseline conditions at the

Proposed Development Site and its surroundings, any mitigation measures

required to prevent, reduce or offset any significant adverse effects and the likely

residual effects after these measures have been employed.

11.1.3. The assessment considers:

• The present-day and future baseline conditions during construction and

operation;

• The effects of enabling works and construction of the Proposed

Development on air quality for human health and ecosystems, with

respect to associated construction traffic, construction plant emissions

and construction dust;

• The effects of operational process emissions associated with the

Proposed Development on air quality for human health and ecosystems;

and,

• The cumulative effects of emissions associated with the Proposed

Development and other committed developments in the vicinity.

Consultation



methodology and content of this chapter and subsequent ES.

11.1.5. Table 11-1 provides a summary of stakeholder comments relevant to air quality

and how they have been incorporated into this PEI Report chapter.

Table 11-1: Summary of Consultation Responses Relevant to Air Quality

Consultee Key Issues / comments

Location of

information in

Chapter


Noting the proximity of the site to the designated Cribbs Causeway Air Quality Management Area (AQMA), it is suggested that changes should be assessed in relation to compliance with European air quality limits and AQMAs.

Section 11.3 and 11.5


May 2014 Page 11-2

Table 11-1: Summary of Consultation Responses Relevant to Air Quality

Consultee Key Issues / comments

Location of

information in

Chapter

Consider whether use of the 2010 Local Monitoring Data, supplemented by Local Authority diffusion tube sampling and Defra background air quality maps, is sufficiently thorough, accurate, up to date and takes account of other development proposed in the vicinity.


The ES should clearly explain the relationship between stack heights and dispersion of emissions to air.


The assessment should take account of both the air emissions from the proposed development and emissions related to increased vehicular movements.

Section 11.5

The impacts on the Severn Estuary should be carefully assessed.

Section 11.5

Air quality and dust emissions should be considered not only on site but also off site, including along access roads, local footpaths and other PROW.

Section 11.5

SGC

It would be prudent to consider monitoring, possibly with automatic analysers, at the point of predicted maximum impact to quantify the impact of the proposed development and other proposed development in the area.


BCC

It would be prudent at this stage not to rule out ambient monitoring of potential air quality impacts considering the potential cumulative impacts from this and other committed developments in the area.


EA No written response relevant to air quality. -

Countryside Council for Wales (CCW)

Depending on the quantities and nature of material that may be discharged to air, the restriction of assessment of possible impacts to 10km is not necessarily appropriate for European sites. We recommend that 10km is used as an initial screening distance to determine whether there are any impacts on designated features. If the assessment identifies potential impacts then increasing the search beyond 10km may be pertinent.

Section 11.5

South Wales Fire and Rescue Service

The ES should include information as to the environmental impact of the project on South Wales.

Section 11.5


May 2014 Page 11-3

11.1.6. Following receipt of the scoping opinion, technical notes on preliminary stack

height determination work and the proposed approach to gathering baseline data

were issued to the EA, SGC and BCC, which led to additional comments being

received on the proposed methodology. Other than SGC recommending that a

suitable bias adjustment should be applied to the primary data collection in this

PEI Report, the suggested approach (outlined in this chapter) was accepted by

the EA, SGC and BCC.


11.1.7. A summary of planning policy relevant to this assessment is provided in

Appendix D: Volume II of this PEI Report.

11.1.8. The principal air quality legislation within the United Kingdom is the Air Quality

Standards Regulations 2010 (Ref. 11-1) which transposes the requirements of

the European Ambient Air Quality Directive 2008 (Ref. 11-2) and the 2004 Fourth

Air Quality Daughter Directive (Ref. 11-3).

11.1.9. The Regulations set air quality limits for a number of major air pollutants that

have the potential to impact public health, such as nitrogen dioxide (NO2),

sulphur dioxide (SO2) and particulate matter. Target values for other pollutants

including critical levels for the protection of vegetation and ecosystems are also

included.

11.1.10. The UK Government has produced a National Air Quality Strategy (NAQS) (Ref.

11-4), which contains air quality objectives and timescales to meet the objectives.

These objectives apply to outdoor locations where people are regularly present

and do not apply to occupational, indoor or in-vehicle exposure. It requires Local

Authorities to undertake an assessment of local air quality to establish whether

the objectives are being achieved, and to designate Air Quality Management

Areas (AQMAs) if improvements are necessary to meet the objectives. Where an

AQMA has been designated, the Local Authority must draw up an air quality

action plan (AQAP) describing the measures that will be put in place to assist in

achieving the objectives.

11.1.11. The current objectives and assessment criteria applicable to the protection of

human health and/or local air quality management are presented in Table 11-2.

Concentrations are expressed in micrograms per cubic metre (µg/m3), unless

otherwise stated. This does not apply to workers or commercial/ industrial

premises, which are subject to the Health and Safety limits (which are typically a

factor of 1,000 less rigorous than the Air Quality Strategy objectives and

therefore are not likely to be exceeded by the Proposed Development).


May 2014 Page 11-4

Table 11-2: Air Quality Strategy Objectives – Protection of Human Health

Pollutant Objective

(µg/m3)

1

Averaging

Period Percentile

Nitrogen Dioxide (NO2) 200 1-hour

99.8th

(18 exceedances/year)

40 Annual Mean

Sulphur Dioxide (SO2)

266 15-minute 99.9

th


350 1-hour 99.7

th


125 24-hour 99.2

nd


Particulate Matter (PM10) 2

50 24-hour 98

th


40 Annual Mean

Particulate Matter (PM2.5) 3 25 Annual Mean

Carbon monoxide (CO) 10,000 8-hour 100

th


Lead (Pb) 0.25 Annual Mean

1,3 butadiene 2.25 Annual Mean

Benzene 5.0 Annual Mean

Polycyclic Aromatic Hydrocarbons (PAH)

0.25 ng/m3 4

Annual Mean

1 µg/m

3 = micrograms per cubic metre – a microgram is a millionth of a gram.

2 PM10 = Particulate matter with an aerodynamic diameter of less than 10 microns (µm).

3 PM2.5 = Particulate matter with an aerodynamic diameter of less than 2.5µm.

4 ng/m

3 = nanograms per cubic metre – a nanogram is a billionth of a gram.

11.1.12. A number of critical levels have also been developed for the protection of

vegetation and ecosystems (CLPVEs), which are presented in Table 11-3.

Table 11-3: Critical Levels for the Protection of Vegetation and Ecosystems

Pollutant Objective

(µg/m3)

Averaging

period Notes

Oxides of nitrogen (NOx as NO2)

75

*30

Daily mean

Annual mean

-

Sulphur dioxide (SO2) 10

1

*20 2

Annual mean 1 For lichens and bryophytes

2 For all higher plants Ammonia

1 1

3 2

Annual mean

Hydrogen fluoride

(HF)

5

0.5

Daily mean

Weekly mean -

Table Notes: * denotes objective set in Air Quality Standards Regulations 2010


May 2014 Page 11-5

11.1.13. The EU Industrial Emissions Directive (IED) (Ref. 11-5) replaces seven separate

EU directives, including the Large Combustion Plant Directive (LCPD) and

Integrated Pollution Prevention and Control Directive (IPPC).

11.1.14. The IED provides operational limits and controls to which Large Combustion

Plant such as the Proposed Development must comply, including Emission Limit

Values (ELVs) for pollutant releases to air.

11.1.15. In addition, a Best Available Techniques (BAT) reference document (BREF) is

published for each industrial sector covered by the IED, which details Achievable

Emission Levels associated with the use of BAT (BAT-AELs). The most recently

finalised version of the Large Combustion Plant BREF was published in 2006

(Ref. 11-6) although it is currently undergoing review. It is therefore considered

that the use of the ELVs specified in the IED for Large Combustion plant will

enable a robust assessment to be carried out of the potential impacts of the


11.1.16. The Environmental Permitting (England and Wales) (Amended) Regulations

2010 (EPR) (Ref. 11-7) transpose the requirements of the IED into UK legislation.

An Environmental Permit will be required for the operation of the Proposed

Development; this would be determined, granted and regulated by the

Environment Agency.


Overview

11.2.1. This section describes the methods used to assess the significance of effects of

emissions from construction phase activities and operation of the Proposed

Development. Baseline conditions, including air quality sensitive receptors that

may be affected by the construction or operation of the Proposed Development,

are discussed in Section 11.3.

11.2.2. The study area for construction road traffic emission impacts extends up to 1.5km

from the Proposed Development Site with receptors identified along routes to and

from the Site. The assessment of road traffic impacts has been based on

conservative traffic estimates for the construction of the Proposed Development.

Further details of the traffic data utilised in the assessment are presented in

Appendix F, Volume II of this PEI, and Chapter 10: Transport and Access.

11.2.3. Road traffic associated with the operation of the Proposed Development will be

minimal and has been scoped out of the Air Quality Assessment.

11.2.4. The study area for combustion emissions extends up to 10km from the Site, in

order to assess the potential impacts on sensitive human health and ecological


May 2014 Page 11-6

receptors, in line with EA EPR H1 guidelines (Ref 11-8). However, in practice the

predicted impacts become negligible beyond a distance of around 3km from the

Proposed Development. The assessment of process emissions has been based

on conservative emission parameters and including statutory obligations to meet

the Emission Limit Values (ELVs) specified in the IED for Large Combustion

Plant, in order to predict the worst-case impact. In addition, the assessment has

taken into consideration the sensitivity of predicted results to model input

variables, and to ultimately identify the realistic worst-case results for inclusion in

the assessment. These variables include 5-years’ data from a representative

meteorological station, varying surface roughness and representation of buildings

and structures that could affect dispersion from the source and are discussed in

Appendix F, Volume II of this PEI Report.

Construction Phase

Assessment of Emissions Generated from Construction Site Plant

11.2.5. As described in Chapter 5: Enabling Works and Construction, it is intended that

the DCO will allow construction to start within 7 years of receipt of the Order. It is

anticipated that the enabling works phase for the Proposed Development will last

approximately 17 months, followed by the construction phase being anticipated to

last a total of 37 months. The current estimated completion date is in 2021,

however in order to provide a robust assessment (and taking into account

baseline conditions and emission factors are predicted to improve with time, and

therefore improve baseline conditions) this assessment is based on the earliest

possible operational date, which is 2019.

11.2.6. Emissions to air during construction activities will be associated with on-site

construction vehicles and plant. The screening criterion in the Design Manual for

Roads and Bridge (DMRB) (Ref 11-9), which states that only properties and

habitat sites within 200m of roads should be considered in traffic assessments,

has been applied to determine the potential for impacts from construction plant

on sensitive receptors for the Proposed Development.

Assessment of Dust Emissions Generated During Construction Works

11.2.7. Fugitive emissions of airborne particulate matter can be produced through a wide

range of site preparation and construction activities, including:

• Earthworks, including the handling, working and storage of materials;

• Construction activities; and

• The transfer of dust-making materials from the site onto the local road

networks (“track-out”).


May 2014 Page 11-7

11.2.8. The Proposed Development is not anticipated to include the requirement for

demolition activities, therefore this scenario is not considered further.

11.2.9. ‘Dust’ is defined in BS 6069:1994 (BSI, 1994) as particulate matter in the size

range 1µm - 75µm in diameter, and is primarily composed of mineral materials

and soil particles. This definition is also referred to in NPPF technical guidance

(Ref 11-10) in the context of dust impacts from mineral extraction operations and

has been adopted in this assessment.

11.2.10. Respirable particulate matter (PM10) is composed of material with an

aerodynamic diameter of less than 10µm in diameter, and includes the size

fractions of greatest concern to impacts on human health. The majority of

construction dust is larger than 10µm in diameter and, therefore, increased levels

of dust in the air do not necessarily equate to an increase in levels of PM10. In

general, construction dusts rarely represent an adverse risk to human health and

are more typically associated with the consequences of material depositing onto

property and potential nuisance. Particulate matter may therefore have an effect

whilst airborne, or as a result of its deposition onto a surface. Consequently the

nature of the impact requiring assessment varies between different types of

receptor.

11.2.11. The occurrence and significance of dust generated by earth moving operations is

difficult to estimate, and depends heavily upon the meteorological and ground

conditions at the time and location of the work, and the nature of the actual

activity being carried out. The Institute of Air Quality Management (IAQM)

Guidance on Construction Impacts (Ref. 11-11) provides a screening

methodology to assess the risks from construction activities of nuisance dust

soiling, harm to ecological receptors and health effects from increased PM10

emissions on sensitive receptors. The assessment undertaken for this chapter is

consistent with the overarching approach to the assessment of the impacts of

construction and the determination of their significance set out in IAQM guidance.

It considers the significance of potential impacts with standard mitigation in place

and recommends mitigation measures appropriate to the identified risks to

receptors.

11.2.12. At present, there are no statutory UK or EU standards relating to the assessment

or control of nuisance dust. The emphasis of the regulation and control of

construction dust should therefore be the adoption of Best Practicable Means of

working on site. Designing around the use of good practice is a process that is

informed by impact assessments with the intention of avoiding the potential for

significant adverse environmental effects at the design stage and through

embedded mitigation where possible.


May 2014 Page 11-8

11.2.13. Examples of accepted good site practice include guidelines published by the

Building Research Establishment (BRE) (Ref. 11-12), the Greater London

Authority and Considerate Contractor schemes.

11.2.14. A qualitative dust assessment has been undertaken to assess the potential

significance of any effects on sensitive receptors. The steps in the assessment

process are to consider potential sources of emissions on the basis of the three

main activity groupings for this development of earthworks, construction and

track-out. For each activity group the same steps are applied with respect to the

potential impacts at identified receptors, before coming to an overall conclusion

about the likely significance of the effects predicted.

11.2.15. The steps in this assessment are to:

• Identify the nature, duration and the location of activities being carried out;

• Establish the risk of significant effects occurring as a result of these

activities;

• Review the proposed or embedded mitigation measures for good site

practice;

• Identify additional mitigation measures, if necessary, to reduce the risk of

a significant adverse effect occurring at receptors; and,

• Summarise the overall effect of the works with respect to fugitive

emissions of particulate matter and then report the significance of the

effects.

Assessment of Construction Road Traffic

11.2.16. The incomplete combustion of fuel in vehicle engines results in the presence of

hydrocarbons (HC) such as benzene and 1,3-butadiene, as well as the typical

combustion products of CO, PM10, PM2.5 in exhaust emissions. In addition, at the

high temperatures and pressures found within vehicle engines, some of the

nitrogen in the air and the fuel is oxidised to form NOx, mainly in the form of nitric

oxide (NO), which is then converted to NO2 in the atmosphere. NO2 is associated

with adverse effects on human health. Better emission control technology and

fuel specifications are expected to reduce emissions per vehicle in the long term.

Similarly but to a lesser extent, any sulphur in the fuel can be converted to

sulphur dioxide (SO2) that is then released to atmosphere.

11.2.17. Although SO2, CO, benzene and 1,3-butadiene are present in motor vehicle

exhaust emissions, detailed consideration of the associated impacts on local air

quality is not considered relevant in the context of this Proposed Development.

This is because the concentrations of release are not likely to give rise to

significant effects. In particular, no areas within the administrative boundaries of


May 2014 Page 11-9

SGC or BCC are considered to be at risk of exceeding the relevant objectives for

these species, and the risks to achievement of the relevant air quality objectives

from the Proposed Development are considered negligible. Emissions of SO2,

CO, benzene and 1, 3-butadiene from road traffic are therefore not considered

further within this assessment.

11.2.18. Exhaust emissions from road vehicles may affect the concentrations of principal

pollutants of concern, NO2, PM10 and PM2.5, at sensitive receptors in the vicinity

of the development. Therefore, these pollutants are the focus of the assessment

of the significance of road traffic impacts.

11.2.19. Environmental Protection UK (EPUK) (Ref. 11-13) and the Highways Agency

DMRB guidance set out criteria to establish the need for an air quality

assessment. Both guidance documents consider the changes in traffic

anticipated as a result of development, to identify the need for further evaluation

or assessment. For example, in the DMRB guidance changes in traffic flow of

1,000 AADT (Annual Average Daily Traffic) flow or more, or changes in Heavy

Duty Vehicle (HDV) flows of 200 AADT or more are considered to trigger the

need for further evaluation by quantitative assessment. Where changes in traffic

volumes are less than these criteria, significant changes in air quality are not

expected.

11.2.20. Prior to the construction of the Proposed Development, enabling works will be

undertaken at the Site. The enabling works will include the flood protection

measure to raise sections of the site (the Generating Station Site) by

approximately 2.2m to a maximum of 8.5m AOD. This will involve the importation

of approximately 158,000m3 of material to the Site over the course of 6 months.

During this period, the delivery of material will increase the daily flow of HDVs on

the A403 and A4 by about 342 AADT. During the subsequent 37 month

construction period, the Proposed Development is expected to lead to a

maximum of 80 HDV movements per day.

11.2.21. As such, a screening assessment has been undertaken to estimate the

temporary impact of vehicle movements associated with the land raising on

human receptors. The assessment makes use of the DMRB Screening Method

tool for predicting the quantity of pollutants emitted from vehicle movements.

Vehicle emission rates for 2012 have been used in the tool in combination with

the 2012 background concentration data; this is considered to provide a

conservative estimate of emission rates during the enabling works and

construction phase. The screening assessment has also made use of the NOx to

NO2 conversion spreadsheet updated by Defra since the publication of the

guidance document LAQM.TG(09) (Ref. 11-14), data from Defra pollutant

background maps (Ref. 11-15), URS diffusion tube measurement data, and the


May 2014 Page 11-10

NO2 with Distance from Road Calculator made available by Defra (Issue 4, Defra,

2011).

11.2.22. The assessment also considers the impact of the construction related vehicle

emissions on the Severn Estuary SPA/SAC/Ramsar and SSSI. Following the

methodology described within the DMRB, the change in annual mean NOX

concentrations and nitrogen deposition rates as a result of construction vehicle

movement emissions has been quantified along a transect across this habitat

site.

Operational Phase

11.2.23. Emissions from the operational Proposed Development have been assessed

following the EPR H1 methodology. Detailed dispersion modelling using the

atmospheric dispersion model ADMS5 has been used to calculate the ground

level concentrations at identified receptors. These concentrations have been

compared with the air quality objectives for each pollutant species. The

assessment has been based on operational design parameters under

consideration for the Proposed Development, as described in Section 11.2.31 to

11.2.37. As mentioned above, the first year of operation of the Proposed

Development is assumed to be 2019 for the purpose of this assessment, which is

the earliest date that the Proposed Development could conceivably start to export

power.

11.2.24. The IED defines ELVs for gas turbines (including CCGTs) for NOX, SO2, CO and

PM10, however emissions of SO2, CO and PM10 from gas-fired plant are at such

low levels that they are considered trivial and, as discussed above, the risk to the

achievement of the CO and SO2 air quality objectives is considered negligible.

These emissions have therefore been screened from further assessment. The

emissions of NO2 have been considered further as there is a potential risk to the

achievement of the objectives identified within the study area.

11.2.25. An assessment of nutrient enrichment (and eutrophication) and acid deposition at

Statutory Habitat sites, featuring sensitive ecological receptors, has been

undertaken following EA guidance AQTAG06 (Ref. 11-16) and using data

obtained from APIS (Ref. 11-17). Non-statutory habitat sites have not been

assessed as the sensitive species present at these receptors and their

associated critical loads for nutrient and acid deposition are not on public records

and no critical levels are available.

Dispersion Model Selection

11.2.26. Dispersion modelling calculates the predicted ground level concentrations arising

from the emissions to atmosphere, based on Gaussian approximation


May 2014 Page 11-11

techniques. The model employed has been developed for UK regulatory use and

its use in such assessments is approved by the EA.

11.2.27. ADMS5 uses a continuous calculation method to determine the conditions of the

receiving atmosphere based on the Monin-Obukhov length, which represents the

height of the boundary layer and the degree of turbulence within the atmosphere.

This is generally regarded as a more comprehensive modelling approach than

that employed by older models such as ISC, which use discrete approximations

to the atmospheric conditions known as Pasquill stability classes. The degree of

turbulence in the atmosphere affects the rate at which pollutants from point

sources are dispersed in the environment. The more unstable the atmosphere,

for example due to high solar insolation, the greater the degree of mixing. While

this is in principle the desired effect for the release of pollutants through stacks at

elevated heights, this can also lead to localised peak concentrations if the plume

is rapidly brought to ground level.

11.2.28. ADMS5 utilises site-specific hourly sequential meteorological data to enable a

realistic assessment of dispersion from point sources to be conducted for

meteorological conditions that are directly applicable to the site.

11.2.29. Various parameters can affect the degree of dispersion from a source, and these

are accounted for in the modelling scenario where appropriate. The presence of

elevated or complex terrain in the vicinity of the source can affect the flow pattern

of the wind field, which can in turn bring a plume to ground more rapidly.

Buildings of sufficient height located close to the emissions sources can affect

dispersion – inducing downwash in the emitted plume and entraining pollutants

towards ground level.

11.2.30. The detailed model parameters are presented and discussed within Appendix F,

Volume II of this PEI Report. Sensitivity of the predicted concentrations to

variations in these model representations has been undertaken to ensure that the

reported results provide a realistic worst-case assessment. This is again

discussed in Appendix F, Volume II of this PEI Report.

Proposed Development Emission Parameters

11.2.31. Conservative assumptions have been made with regard to operational

parameters, to determine the maximum effects of the operation of the Proposed

Development on sensitive receptors. These assumptions include:

• Maximum potential operational availability for the CCGT units;

• Operation of peaking plant up to 1,500 hours per year at the same time as

the operation of the main units;


May 2014 Page 11-12

• Maximum emission rates, at IED Emission Limit Values for all combustion

units.

11.2.32. As outlined in Chapter 4: Project Description, the actual hours of operation of the

CCGTs or the peaking plant will be subject to the national demand for electricity

and the economic viability of gas-fired generation, however, it is anticipated that

the CCGTs will operate at an average 31% load factor (an average 2,716 hours

per year) over the course of its lifetime, with the peaking plant expected to run at

a maximum 17% load factor (a maximum 1,500 hours a year).

11.2.33. The existing Seabank 1 & 2 CCGTs have annual average NOx emission

concentrations of approximately half of the IED ELV, and it is considered that the

Proposed Development would operate to a similar level. The above assumptions

of 100% operability and emissions at IED ELVs, should therefore overestimate

the effect on local air quality.

11.2.34. Each CCGT at the Proposed Development will vent to atmosphere via a

dedicated stack. Each peaking plant unit will vent via a dedicated flue, contained

within either individual or common windshields (Ref. 11-18).

11.2.35. As outlined in Chapter 4: Project Description, there are a number of options for

the makeup of the Proposed Development although the overall maximum output

capacity remains fixed at 1,400MWe. Principally these options relate to the

technology selection not being finalised; therefore the two main CCGT units

could be of two different output capacities (700MWe or 580MWe) and could be

constructed in two different configurations (single or multi shaft).

11.2.36. If the lower output capacity units are installed, this allows for the installation of

peaking plant such that the output capacity of the generating station remains at

1,400MWe. At this stage in the project’s development, the Applicant is consulting

on two potential options for the technology of the peaking plant (reciprocating

diesel engines or Open Cycle Gas Turbines (OCGT)) and assessing the impacts

from both options. This provides six potential design configurations for the

Proposed Development that require assessment within this Preliminary

Environmental Information report. The different design schemes configurations

considered within this air quality assessment are detailed in Table 11-4 below.

Table 11-4: Alternative Design Schemes for Combustion Plant

Design

Scheme Units Layout

A 2 x 700 MWe CCGTs (1,400MWe) Single-shaft CCGT

B 2 x 700 MWe CCGTs (1,400MWe) Multi-shaft CCGT

C 2 x 580MWe CCGTs (1,160MWe)

2 x Peaking plant (reciprocating engines) 240MWe Single-shaft CCGT


May 2014 Page 11-13

Design

Scheme Units Layout

D 2 x 580MWe CCGTs (1,160MWe)

2 x Peaking plant (reciprocating engines) 240MWe Multi-shaft CCGT

E 2 x 580MWe CCGTs (1,160MWe)

2 x Peaking plant (OCGT) 240MWe Single-shaft CCGT

F 2 x 580MWe CCGTs (1,160MWe)

2 x Peaking plant (OCGT) 240MWe Multi-shaft CCGT

11.2.37. The relevant stack and emission parameters for the different units are provided in

Table 11-5.

Table 11-5: Modelled Stack Release Parameters

Parameter

CCGT (single

unit, 700MWe

output)

CCGT (single

unit, 580MWe

output)

Peaking Plant

(Recip

Engines,

240MWe)

Peaking Plant

(OCGT,

240MWe)

Stack Height (m) 90 1

90 45 45

Efflux Velocity (m/s) 22.8 19.6 33.5 34.0

Emission Temperature

(°C) 80 80 371 436

Volumetric Flow (Nm3/hr)

2 3,462,000 2,967,000 1,059,000 832,670

Volumetric Flow at stack

exit parameters (Am3/s)

1,009 865 770 667

Flue Diameter (m) 7.5 7.5 4 5

Assumed maximum

operating hours / year 8,760 8,760 1,500 1,500

NOx ELV (IED, mg/Nm3) 50 50 75.0 51.3

Approximate stack

locations

(354111, 182326)

(354162, 182369)

(354313, 182270)

(354325, 182313)

1 Maximum 98.5m AOD

2 Reference conditions 273K, 0% O2, dry

Sensitive Receptors

Construction Phase

11.2.38. Based on the guidance and assessment criteria presented in Section 11.2, it has

been assumed for the purposes of this assessment that the human health

receptors potentially affected by dust soiling, and short term concentrations of

PM10 generated during construction activities, are limited to those located within


May 2014 Page 11-14

350m of the nearest construction activity, and/ or within 200m of a public road

used by construction traffic that is within 500m of the construction site entrance,

beyond which distance any track-out would be expected to be minimal.

Ecological receptors have been assumed to be limited to those located within

100m of the nearest construction activity and/ or within 100m of a public road

used by construction traffic that is within 500m of the construction site entrance.

11.2.39. The Proposed Development is located in a predominantly industrial area to the

north of Avonmouth. The nearest receptors that are sensitive to dust soiling and

short term concentrations of PM10 include the neighbouring industrial premises to

the north and south, and the agricultural land to the east. Such receptors are

considered to have a low sensitivity to the effects of dust soiling and increases in

short term emissions of PM10.

11.2.40. The nearest residential receptors to the Proposed Development Site construction

works are Hallen Farm and Stowick Farm, approximately 1.1km from the

Proposed Development Site. The nearest residents to the proposed cooling

water pipeline corridor are approximately 800m from the nearest point of the

corridor. At this distance, the impact of dust soiling and short term concentrations

of PM10 would not be perceptible above background levels. A number of

commercial premises are immediately adjacent to the proposed cooling water

pipeline corridor.

11.2.41. The nearest designated ecological habitat receptor to the Proposed Development

is the Severn Estuary SAC/SPA/Ramsar/SSSI (including Atlantic salt meadows

and transitional communities), which is located approximately 400m from the

Proposed Development Site boundary and 100m from the construction route

(more than 500m from the site entrance). At this distance, the impact of dust

emissions would not be likely to be significant, based on the guidance applied.

11.2.42. Receptors potentially affected by the emissions associated with construction

phase vehicle movements are those located within 200m of a public road used by

construction traffic to access the Site. For this development, it is proposed that

construction vehicles associated with the enabling works will use the A403 and

A4 to the south to access the Site. Sensitive receptors adjacent to this route

include the Severn Estuary to the immediate west of the A403, and residential

properties located on Avonmouth Road (including the AQMA declared by BCC

and designated for NO2) and Portway in Avonmouth to the south of the Site.

Operational Phase

11.2.43. Receptors potentially affected by operational emissions from the Proposed

Development are summarised in Table 11-6 below. The assessment includes the

receptors that are predicted to receive the highest impacts resulting from the


May 2014 Page 11-15

point source contributions, identified through examination of isopleth figures of

pollutant dispersion. The identified receptors also include designated AQMAs in

the locality.

Table 11-6: Operational Phase – Potential Human Health Receptors

Receptor Sensitive Receptor Type of

Receptor Grid Reference

Distance from

Site (km) and

direction

1 Severn Beach Residential 354400,184150 1.8km north

2 Severn Beach Primary School

School 354190,184690 2.4km north

3 Marsh Common Residential 356500,183400 2.6km northeast

4 Easter Compton Residential 356750,182850 2.7km east

5 Elmore Farm Residential 356000,182300 1.9km east

6 Stowick Farm Residential 354800,180800 1.7km southeast

7 Elmington Manor Farm

Residential 355700,181600 1.8km southeast

8 Berwick Farm Residential 355600,180650 2.3km southeast

9 Hallen Farm Residential 354600,180400 2.0km south

10 Footpaths PROW* 353800,181200 1.0km south

11 Cribbs Causeway AQMA 357760,181425 3.8km east

12 Avonmouth Road/M5 AQMA 352493,177720 4.9km south

*Public Right of Way

11.2.44. Ecological receptors potentially affected by operational emissions include the

Severn Estuary habitat site, of which the most sensitive habitat species type is

listed as Atlantic salt marshes. It is recognised that this most sensitive habitat site

is not located in the immediate vicinity of the Proposed Development site, rather

it is on the Welsh side of the Estuary, however in order to carry out a worst case

assessment, this habitat site has been assumed for the whole of the SSSI.

11.2.45. Statutory designated sites including SSSIs and SACs up to 10km from the

Proposed Development have also been considered, as detailed in Table 11-7

below. No national or local nature reserves have been identified within 2km of the

Proposed Development. The assessment includes the predicted NOX impacts at

the identified ecological receptors and impacts from nutrient nitrogen and acidity

deposition on the Severn Estuary SAC/SPA/Ramsar/SSSI, as this is the

ecological receptor predicted to receive the highest impacts. Details of the sites

and reasons for designations are provided in Chapter 16: Ecology.


May 2014 Page 11-16

Table 11-7: Statutory Designated Sites of Ecological Interest within 10km of the


Site Distance from Site (km)

and direction Designation

Severn Estuary

(Atlantic salt marshes)

0.4km west (at nearest point)

SAC, SPA, Ramsar site, SSSI

Horseshoe Bend 5.5km south SSSI

Avon Gorge 7.0km south SAC, SSSI

Bushy Close 7.1km northwest SSSI

Gwent Levels – Magor and Undy 7.3km northwest SSSI

River Wye 8.0km north SAC, SSSI

Nedern Brook Wetlands, Caldicot 8.3km northwest SSSI

Weston Big Wood 8.3km southwest SSSI

Ashton Court 9.5km south SSSI

Weston-In-Gordano 9.5km southwest SSSI

Evaluation of Significance

Construction Dust

11.2.46. For potential amenity effects, such those related to dust deposition, the aim is to

bring forward a scheme, to include mitigation measures if necessary, that

minimises the potential for complaints to be generated as a result of the

Proposed Development construction works.

11.2.47. The scale of the risk of adverse effects occurring from each main type of

construction activities, with mitigation in place, is described using the terms high,

medium and low risk. The basis for the choice of descriptor is set out for each

section of the construction works assessment presented below. Experience in the

UK is that good site practice is capable of mitigating the impact of fugitive

emissions of particulate matter effectively, so that in nearly all circumstances,

effects can be controlled to be not significant at the distances identified receptors

are from the Proposed Development site (Ref. 11-11).

11.2.48. Table 11-8 presents the significance criteria for assessing dust effects.

Table 11-8: Descriptors Applied to the Predicted Adverse Effects of Fugitive

Emissions of Particulate Matter

Significance of Effect

at Single Receptor Description

Major A significant effect that is likely to be a material consideration in its own right


May 2014 Page 11-17


at Single Receptor Description

Moderate A significant effect that may be a material consideration in combination with other significant effects, but is unlikely to be a material consideration in its own right.

Minor An effect that is not significant but that may be of local concern.

Negligible An effect that is not significant change.

Operational Emissions

11.2.49. Table 11-9 presents the criteria employed for the determination of the magnitude

of change for gaseous pollutant and PM10 emissions, based on the percentage

increase in pollutant concentrations due to the Proposed Development.

11.2.50. Table 11-10 presents the significance of potential effects, taking into account the

magnitude of change over baseline conditions and the absolute concentration in

relation to air quality objectives. Particular significance should be given to a

change that takes the concentration from below to above the NAQS objective or

vice versa because of the importance ascribed to the objectives in assessing

local air quality.

11.2.51. Table 11-9 has been modified slightly from the criteria presented in the EPUK

guidance to accommodate the terms High to Very Low for magnitude of change

and the terms ‘Major’, ‘Moderate’ and ‘Minor’ in relation to significance of effect,

as described in Chapter 7: Assessment Methodology, to ensure consistency with

other assessment chapters within this report.

Table 11-9: Determination of Magnitude of Change – Air Quality

Magnitude of

change

Annual Mean Process Contribution

Concentration NO2 and PM10 (µg/m³) Days PM10 >50µµµµg/m

3

High Increase/decrease >4 (>10%) Increase/decrease >4

Medium Increase/decrease 2 – 4 (5-10%) Increase/decrease 2 - 4

Low Increase/decrease 0.4 – 2 (1-5%) Increase/decrease 1 - 2

Very Low Increase/decrease < 0.4 (<1%) Increase/decrease <1


May 2014 Page 11-18

Table 11-10: Significance of Effects

Absolute Concentration (Predicted

Environmental Concentration - PEC) in

Relation to Objective/Limit Value

Change in Concentration

High Medium Low Very Low

Increase with Proposed Development

Above Air Quality Standard or Guideline with the Proposed Development (>40 µg/m

3,

>100%)

Major Adverse

Moderate Adverse

Minor Adverse

Negligible

Just Below Air Quality Standard or Guideline with the Proposed Development (36 - 40 µg/m

3, 90-100%)

Moderate Adverse

Moderate Adverse

Minor Adverse

Negligible

Below Air Quality Standard or Guideline with the Proposed Development (30 - 36 µg/m

3,

75-90%)

Minor Adverse

Minor Adverse

Negligible Negligible

Well Below Air Quality Standard or Guideline with the Proposed Development (<30 µg/m

3,

<75%)

Minor Adverse

Negligible Negligible Negligible

Decrease with Proposed Development

Above Air Quality Standard or Guideline with the Proposed Development (>40 µg/m

3,

>100%)

Major Beneficial

Moderate Beneficial

Minor Beneficial

Negligible

Just Below Air Quality Standard or Guideline with the Proposed Development (36 - 40 µg/m

3, 90-100%)

Moderate Beneficial

Moderate Beneficial

Minor Beneficial

Negligible

Below Air Quality Standard or Guideline with the Proposed Development (30 - 36 µg/m

3,

75-90%)

Minor Beneficial

Minor Beneficial


Well Below Air Quality Standard or Guideline with the Proposed Development (<30 µg/m

3,

<75%)

Minor

Beneficial Negligible Negligible Negligible

11.2.52. The evaluation of significance of the impacts associated with process emissions

has been based on the criteria outlined in the EA EPR H1. This indicates that for

the assessment of point source emissions, long term ground level pollutant

concentrations resulting from point source emissions which are less than 1% of

an NAQS objective can be treated as insignificant (or negligible). Similarly, short

term ground level pollutant concentrations resulting from point source emissions

which are less than 10% of an NAQS objective can also be treated as

insignificant (or negligible). Where emissions are not screened as negligible, the

descriptive terms for the significance of the effect, outlined in Table 11-11, have

been applied.

11.2.53. The significance of effects of point source emissions on ecological receptors,

through deposition of nutrient nitrogen or acidity, has been evaluated using the

EA insignificance criterion of 1% of the long term critical level objective, as


May 2014 Page 11-19

above, in the absence of any specific guidance. At this stage no evaluation of

contribution to critical loads has been undertaken; the need for this will be

considered following Stage 2 consultation and, if required, included in the final

ES.


Construction Phase

11.2.54. The Rochdale Envelope parameters do not significantly affect the input

parameters utilised in the construction air quality assessment, and

consequentially the outcome of this assessment will not vary under the Envelope

applied. Therefore, no further discussion of the Rochdale Envelope parameters is

provided in relation to construction phase effects and the assessment adopts

conservative (worst case) values where assumptions are necessary.

Operational Phase

11.2.55. The key parameters for the assessment of air quality effects from the Proposed

Development operational phase are considered to be:

• Selection of technology for combustion processes with influence on NOx

emissions to air in particular;

• Building heights and layouts associated with the combustion technology;

and,

• Stack heights.

11.2.56. At this design stage, the specific technology, and hence the final combustion

emission parameters, have not been fixed. The air quality effects have therefore

been based on the maximum (worst-case) parameters. This is discussed in detail

in Appendix F, Volume II of this PEI Report.


11.3.1. This section discusses the existing conditions and secondary and primary data

collection.

Publicly Available (Secondary) Air Quality Data

11.3.2. Baseline air quality conditions in the vicinity of the Proposed Development Site

have been evaluated through a review of local authority air quality management

reports, Defra published data, and other sources. As previously described, the

key pollutants of concern resulting from construction and operation of the

Proposed Development are NO2, CO, PM10 and PM2.5, therefore the assessment

of baseline conditions considers these pollutants only.


May 2014 Page 11-20

Local Air Quality Management

11.3.3. The statutory review and assessment of local air quality by SGC in 2010 resulted

in designation of three AQMAs for the potential to exceed the annual NO2 NAQS

objective, of which the closest, Cribbs Causeway adjacent to the M5, is 4km east

of the Proposed Development Site. Revocation of the Cribbs Causeway AQMA

was recommended by SGC in a further assessment undertaken in 2011,

however this was not agreed by Defra and the AQMA designation still currently

stands.

11.3.4. The statutory review and assessment of local air quality within the area by BCC

resulted in the designation of an AQMA for Bristol city centre and main radial

roads for the potential to exceed the annual NO2 and annual PM10 NAQS

objectives, as a precautionary measure. An additional small area, where

Avonmouth Road is crossed by the M5, is in the process of being designated an

AQMA for NO2. The Proposed Development Site is 5km north of Avonmouth

Road AQMA and 7.5km northwest of the Bristol AQMA, along the A38.

11.3.5. Monitoring undertaken by SGC and BCC includes a number of continuous

monitoring stations (including NO2 and PM10) and a network of NO2 diffusion

tubes, covering background sites and also sites representative of exposure for

sensitive receptors. Monitoring data from these automatic and non-automatic

sites in the area are presented in Table 11-11 below for 2012 (the most recent

year’s ratified data available at the time of writing).

Table 11-11: Ambient Data from Local Authority Secondary Sources

Authority Type Location Location

from site

Data

Capture

(%)

2012

NO2

(µg/m3)

2012

PM10

(µg/m3)

2012

SGC Automatic (UB)

Filton – Conygre House

7.3km SE

96.8 20 18

Automatic (R)

Yate – Station Road

16.3km E

90.3 27

24

Diffusion tube (UB)

Severn beach primary school

2.3km N

100 17.6 -

Diffusion tube (RF)

Cribbs Causeway – Blackhorse Hill Hollywood Cottage

3.9km E

100 35.0 -

BCC Diffusion tube (RF)

Avonmouth Rd (in AQMA)

4.9km SW

100 34.7 -

Diffusion tube (RF)


4.9km SW

90 34.0 -

Diffusion tube (RF)


4.9km SW

100 31.8 -


May 2014 Page 11-21

Authority Type Location Location

from site

Data

Capture

(%)

2012

NO2

(µg/m3)

2012

PM10

(µg/m3)

2012

Automatic (UB)

St.Pauls AURN (in Bristol AQMA)

10.1km SE

98.6 31.5

Notes: UB =Urban Background, R=Roadside, RF=Roadside Façade

11.3.6. The nearest current automatic monitoring station is located at Filton, 7.3km

southeast of the Proposed Development Site, in an urban location which would

be expected to experience typically higher NO2 contributions from road traffic

than the rural and semi-rural areas likely to be impacted by emissions from the


11.3.7. There are no sources of monitored PM10 or PM2.5 data in the Avonmouth area. In

the absence of monitored data, baseline PM10 and PM2.5 conditions are

represented by the Defra background maps (see below).

11.3.8. Historic NO2 monitoring undertaken in 2007 around Seabank 1 & 2 has also been

provided by BCC. This monitoring included a number of diffusion tube sites along

the estuary road to the west of the Proposed Development Site and adjacent to

the Severn Estuary SAC/SPA/Ramsar/SSSI. An automatic monitor was also

located at Almondsbury, an area broadly representative of rural receptors to the

northeast of the Proposed Development. The most recent year’s data (2007)

obtained from this monitoring campaign is provided in Table 11-12.

Table 11-12: Historic Ambient NO2 Monitoring Data

Type Location Grid Ref (x,y) Location

from Site

NO2 (µg/m3)

2007

Diffusion tube Holesmouth, adjacent to fuel depot and rail-line

352107, 180804 2.5km SW 36

Diffusion tube Chittening Warth, background location

353511, 182902 0.8km W 22

Diffusion tube Severn Beach, background location

353710, 183826 1.5km N 24

Automatic (UB) Almondsbury School 360270, 183962 6.4km NE 16.4

11.3.9. The 2007 data from background diffusion tube monitoring locations at Severn

Beach and Chittening Warth, which are only 800m and 1.5km west of the

Proposed Development Site, are higher than the automatic monitoring data but

are likely to have been influenced by the adjacent former ICI/Terra Nitrogen

works that were operational until 2008.


May 2014 Page 11-22

Defra Published Data

11.3.10. Defra published maps of background air quality concentrations indicate that NOx

and NO2 concentrations within the surrounding area vary considerably depending

on the local contributory sources. For example the area to the north of Seabank 1

& 2, near to the Severn Road, has much higher NOx than the open areas to the

south. The range of concentrations away from the industrial areas at Chittening is

15-17µg/m3. The mapped data has therefore been obtained for the locations of

likely maximum impact from emissions from the Proposed Development and are

shown in Table 11-13. Projected concentrations for 2019 are also provided.

Table 11-13: Defra Mapped Background Data (1km grid squares)

Receptor Grid Ref.

NO2

(µg/m3)

NOx

(µg/m3)

PM10

(µg/m3)

PM2.5

(µg/m3)

2012

Human Health (downwind of Proposed Development)

355500, 182500

16.6 24.1 14.7 9.4

Human Health, Avonmouth AQMA 352500, 178500

26.5 - 18.0 12.5

Severn Estuary SSSI (N of Seabank 1&2)

353500, 183500

23.7 37.7 - -

Severn Estuary SSSI (W of Seabank 1&2)

353500, 182500

14.9 21.3 - -

Severn Estuary SSSI (SW of Seabank 1&2)

352500, 181500

13.8 19.6 - -

2019

Human Health (downwind of Proposed Development)

355500, 182500

13.3 18.7 14.2 8.9

Human Health, Avonmouth AQMA 352500, 177500

21.6 - 16.7 11.1

Severn Estuary SSSI (N of Seabank 1&2)

353500, 183500

20.1 30.7 - -

Severn Estuary SSSI (W of Seabank 1&2)

353500, 182500

12.1 16.9 - -

Severn Estuary SSSI (SW of Seabank 1&2)

352500, 181500

11.4 15.8 - -

Existing Particulate Sources

11.3.11. A background level of dust exists in all urban and rural locations in the UK. Dust

can be generated on a local scale from vehicle movements and from the action of

wind on exposed soils and surfaces. Dust levels can also be affected by long

range transport of dust from distant sources into the local vicinity.


May 2014 Page 11-23

11.3.12. Receptors currently experience dust deposition at a rate that is determined by the

contributions of local and distant sources. This baseline rate of soiling varies

dependent on prevailing climatic conditions and works being undertaken in the

area. The tolerance of individuals to deposited dust is typically shaped by their

experience of baseline conditions.

11.3.13. Existing local sources of particulate matter include industrial emissions from

nearby facilities, agricultural emissions form the farmland to the east, exhaust

emissions and brake and tyre wear from road vehicles and the long range

transport of material from outside the study area.

Existing and Proposed Industrial Combustion Sources

11.3.14. Existing industrial sources of emissions to air that are likely to have a significant

influence on local air quality include Seabank 1 & 2 to the immediate west of the

Proposed Development. It is considered that emissions from Seabank 1 & 2 have

been taken into consideration in the interpretation of the baseline data, as

discussed in the Section below.

11.3.15. Proposed industrial sources of emissions to air that could influence local air

quality in the vicinity of the Proposed Development have been identified and are

described in Section 11.7 – Cumulative Effects Assessment.

Primary Data Gathering – Diffusion Tube Monitoring

11.3.16. Additional diffusion tube monitoring has been undertaken by the Applicant in the

vicinity of the Proposed Development Site to provide more data on the

background air quality in this location and to supplement the publicly available

data. A total of seven locations were agreed with SGC, BCC and the EA to

monitor concentrations of NO2 and NOX. These locations are described in Table

11-14 and illustrated in Figure 11-1 (Volume III).

Table 11-14: Primary Diffusion Tube Monitoring Locations

Ref. Location Grid Ref. Description Located

1 Seabank 3 354215, 182429 Urban background site, avoiding location downwind of Seabank stacks, >100m from road.

Fence

2 Seabank 1 & 2 353420, 182578 Urban background site, avoiding location downwind of the existing stacks >100m from road.

Fence

3 Severn Way Mobile Phone Mast

353330, 182621 >5m and upwind of road, relevant exposure for SSSI.

Fence/ Lamppost

4 Background location

353718, 183504 Relevant exposure for SSSI, >100m from road, no nearby significant sources.

Fence


May 2014 Page 11-24

Ref. Location Grid Ref. Description Located

5 Severn Beach Primary School

354192, 184687

Urban background site, duplicate to SGC tube, representative of likely long term maximum impact at SSSI from Proposed Development operations.

Lamppost

6 Marsh Common, Pilning

356509, 183394 >5m from road, relevant exposure for residential receptors.

Lamppost

7 Brook Farm, Vimpenny's Lane

356260, 182060 Residential receptor, >200m from M5 motorway.

Lamppost

11.3.17. Three months of data have been gathered, with the diffusion tubes deployed for a

month at a time, thereby providing three results over the sampling period. The

average diffusion tube results across the three samples are presented in Table

11-15 below. The data has been annualised using data from Bristol St. Pauls,

Chepstow and Newport (June-Sept, 2013) and bias adjusted (Gradko, 09/13).

Table 11-15: Mean monitored Concentrations, 4 June - 30 Sept 2013 (µg/m3)*

Ref. Location Mean NO2

(µg/m3)

Mean NOx

(µg/m3)

1 Seabank 3 (UB) 22.6 23.9

2 Seabank 1 & 2 (UB) 23.3 26.8

2a Seabank 1 & 2 (duplicate) (UB) 22.0 28.1

3 Severn Road Mobile Phone Mast, adjacent to the road (R)

37.7 50.8

4 Background location, adjacent to Severn Estuary SSSI (UB)

19.8 22.1

5 Severn Beach Primary School (UB) 25.4 35.4

6 Marsh Common, Pilning (R) 25.8 33.9

7 Brook Farm, Vimpenny's Lane (UB) 20.3 25.2

* Note – Annualisation factors: NO2 1.37, NOx 1.41

Bias adjustment factor 0.96 (Gradko, 09/13).

11.3.18. The average measured NO2 concentration across all diffusion tubes deployed is

22.7µg/m3 (excluding 1 outlier) which meets the annual mean NAQS objective.

The outlier at Location 3, shows an NO2 concentration of 37.7µg/m3, and is

significantly above the average, however this monitoring location is less than

10m from the A403 (Severn Road) and the railway line, and within 5m of a lay-by

regularly used by HGVs; it is not considered to be a true background location.

The nearest comparable monitoring location away from the roadside is Location

1 at Seabank 1 & 2, 100m from Location 3, which shows considerably lower NO2

and NOx concentrations. This supports the opinion that Location 3 may be

experiencing higher concentrations as a result of road traffic sources and also


May 2014 Page 11-25

idling vehicles in the lay-by, which were observed during collection and

redeployment of the tubes. The contribution of vehicle emissions to local air

quality conditions drops rapidly with distance from the road (typically to

background levels within 200m of the road source (Ref 11-9)), which is supported

by the diffusion tube data. SGC and BCC have provisionally agreed that Location

3 is not representative of background concentrations.

Derivation of Baselines used in the Assessment

11.3.19. The construction phase and operational phase of the Proposed Development are

anticipated to impact upon different receptor locations, with the construction

impacts concentrated locally to the Site and along the A403 and A4 for

construction traffic; whereas the operational impacts will be dominated by point

source emissions with long term impacts in the prevailing wind direction to the

northeast of the Proposed Development (towards Easter Compton and Marsh

Common) and peak short term impacts occurring locally to the Site. The

background concentrations have been derived for these receptor locations and

phases and are summarised in Table 11-16 below.

NO2 – Human Health Impacts

11.3.20. The baseline data available within the principal study area indicates that annual

mean concentrations of NO2 are typically well below the NAQS objective at

sensitive human health receptor locations. The diffusion tube results (excluding

the outlier) indicate that the background NO2 concentration in the site vicinity is

19-23µg/m3, and this data is supported by the nearest current automatic

monitoring station at Filton (20µg/m3) and historic monitoring. The Defra

background gridded data indicate typically lower background concentrations than

those from the diffusion tubes (around 17µg/m3), as would be expected from data

averaged over a 1km2 scale. The long term NO2 concentration in the study area

at key human health receptor locations is therefore assumed to be 23µg/m3 in

2012 and 18µg/m3 in 2019, for a conservative assessment of annual average

impacts. Short term impacts have been assessed assuming twice the long term

average background concentration in accordance with EA H1 guidance.

11.3.21. The assessment of peak construction traffic effects on the Avonmouth AQMA has

assumed baseline air quality derived from Defra mapping for this location. DMRB

has been used to estimate the NO2 concentration at the façade of the buildings

and therefore to verify the concentration against diffusion tube data. The 2012

value obtained using a Defra background of 28µg/m3 was 35-36µg/m3 which

compares well with the BCC diffusion tube monitoring data of 34-35µg/m3 at

these locations.


May 2014 Page 11-26

NOX – Ecological Impacts

11.3.22. The construction traffic assessment of effects on the Severn Estuary habitat site

has assumed the background NOx concentrations based on the Defra gridded

data for the grid squares containing this habitat site along Chittening Warth (as

shown in Table 11-13). The marked difference between the baseline

concentrations in areas north and west of the Proposed Development (a

difference of 10µg/m3 NO2) is assumed to be principally the result of road traffic

and existing industrial and commercial sources, including Seabank 1 & 2 and

commercial developments north of the Proposed Development Site; these

sources have therefore been taken into account in the baseline of the air quality

assessment.

11.3.23. Two ecological receptor locations have been assessed for traffic impacts, based

on the higher concentration (north) and lower concentration (southwest) from

Defra gridded baseline data.

11.3.24. The reduction in NO2 concentrations, as the result of anticipated improvements in

UK national vehicle fleet year on year, has been assumed up to the traffic

assessment for peak construction year (2017).

11.3.25. Three ecological receptor locations have been assessed for the assessment of

operational plant emissions, representing locations north, west and southwest of

the Proposed Development Site.

11.3.26. The 2019 baseline NOx concentration has also been used for the point source

assessment as a conservative assumption, although Defra projections indicate

that this concentration should reduce further by the opening operational year of

the generating station.

Particulates

11.3.27. Filton automatic monitoring station, located 7km southeast of the Proposed

Development Site is the nearest automatic monitor to the Proposed Development

and has recorded relatively stable PM10 concentrations for the last five years,

between 17-20µg/m3, which are well below the annual NAQS objective. Defra

gridded data for the potential receptors of emissions from the Proposed

Development indicates that baseline PM10 and PM2.5 are well below their

respective national air quality objectives of 40µg/m3 and 25µg/m3. The Defra

values, as detailed in Table 11-13, have been assumed for assessment of point

source and traffic impacts at the worst case receptors.

11.3.28. Table 11-16 presents a summary of the derived baseline concentrations for each

type of receptor and phase of development used in the assessment.


May 2014 Page 11-27

Table 11-16: Derived Baseline Concentrations (µg/m3)

Pollutant Receptor Source Baseline Concentration

2012 2019

NO2 Human health – AQMA

Construction traffic 26.5 21.6

NO2 Human health – AQMA

Operation 35.0 35.0

NO2 Human health Operation 23.0 18.1

NOX Ecological - north Operation, Construction traffic

37.7 30.7

NOX Ecological - west Operation, Construction traffic

20.9 16.9

NOX Ecological – south west

Operation, Construction traffic

19.6 15.8

PM10 Human health Construction traffic 18.0 16.7

PM10 Human health Operation 14.7 14.1

PM2.5 Human health Construction traffic 12.5 11.1

PM2.5 Human health Operation 9.4 8.9

Deposited Nitrogen

11.3.29. Based on the above data, the baseline NOx concentrations and nitrogen

deposition rates have been predicted using the DMRB tool at the transect of the

Severn Estuary SPA/SAC/Ramsar/SSSI for each of the two traffic assessment

locations, and are provided in Table 11-17. The baseline data is presented for

2019, the earliest year that the Proposed Development could reasonably be

commissioned.

Table 11-17: Predicted Baseline NOx Concentrations and Nitrogen Deposition Rates

at the Severn Estuary, 2019

Distance from A403 (m)

2019 Annual Mean NOx (µg/m

3)

2019 Nitrogen Deposition Rate (kg N/ha/yr)

North South-west

North (based on maximum)

South-west (based on

mean)

25 44.9 30.0 21.2 10.5

30 43.2 28.3 21.1 10.5

40 40.4 25.5 21.0 10.4


May 2014 Page 11-28

Distance from A403 (m)

2019 Annual Mean NOx (µg/m

3)

2019 Nitrogen Deposition Rate (kg N/ha/yr)

North South-west

North (based on maximum)

South-west (based on

mean)

50 38.3 23.4 21.0 10.3

75 34.9 20.0 20.9 10.2

100 33.0 18.1 20.8 10.1

Assessment Criteria

30 20 – 30

11.3.30. Baseline NOx conditions at some sections of the Severn Estuary

SPA/SAC/Ramsar/SSSI within 100m of the A403 are predicted to exceed the

CLPVE of 30µg/m3, in 2019.

11.3.31. The maximum nitrogen deposition rate at this habitat site (according to APIS) in

2012 was 24.8kg N/ha/yr and the mean was 12.0kg N/ha/yr. In recognition of the

higher baseline atmospheric NOX and NO2 concentrations at the northern

ecological assessment location, the higher deposition rate has been assumed for

this location. This is a conservative assumption however, as the APIS reported

rate of deposition (which covers the entire area of the SSSI designation) does not

correlate with the Defra ambient data. The APIS rate of nitrogen deposition is

well below the upper critical load threshold for a salt marsh habitat.


IED Emission Limit Value (ELV) Compliance

11.4.1. The Proposed Development has been designed such that process emissions to

air will comply with the ELVs specified in the IED. This will be enforced by the EA

through the Environmental Permit required for the operation of the generating

station.

Stack Height

11.4.2. The stack height has been optimised with consideration given to minimisation of

ground level air quality impacts, and visual impacts of a taller stack. Preliminary

dispersion modelling was undertaken to determine the optimum stack height

range and local residents informally consulted regarding their preference. Further

information on the determination of the stack height is provided in the Appendix

F, Volume II of this PEI Report.

11.4.3. The selected stack height has been incorporated into the plant design and is

based on a specified value of 90m above the finished ground level (up to 98.5m


May 2014 Page 11-29

AOD) for the CCGT units and 45m (up to 53.5m AOD) for the peaking plant

stacks; therefore if the buildings onsite reduce in size from the maximum

permitted heights and dimensions modelled in this assessment, the stack heights

would remain at 90m and therefore benefit from reduced building effects and

associated increased dispersion.

Stack Locations

11.4.4. The proposed locations of the main CCGT stacks are shown in Table 11-5

above. The exact locations cannot be specified as they are dependent on the

technology configuration selected for the Proposed Development.

11.4.5. The proposed locations of the peaking plant and its stacks were modified during

the design evolution, as outlined in Chapter 6: Project Need and Alternatives,

when preliminary dispersion modelling demonstrated that a lower stack height

and lower offsite effects could be achieved by moving this plant further from the

HRSG buildings.

Visible Plumes

11.4.6. The potential for visible plumes from the CCGT main stacks is considered very

low as a result of the water content and temperature of the flue gas. The Large

Combustion Plant BREF Note (Ref 11-7) states that plume visibility can be

reduced by maintaining stack release temperatures above 80°C, which is the

current design intention for the Proposed Development.

11.4.7. Visible plumes from the proposed hybrid cooling water systems have not been

assessed, as they are not expected to generate a visible plume under most

meteorological conditions. The hybrid cooling water systems are also relatively

low in height – around 19m above the finished ground level. Given the distances

to sensitive receptors the risk of potential nuisance from visible hybrid cooling

water system plumes is considered negligible.


Construction Phase

Assessment of Construction Dust

11.5.1. The nearest receptors to the Site boundary are the local industrial properties to

the north and southwest, and the agricultural land to the east. There are no dust

sensitive residential or ecological receptors within 500m of the construction site

boundary, for either the Proposed Development or proposed cooling water

pipeline corridor. There are a number of commercial receptors adjacent to the

proposed cooling water pipeline corridor, such as warehouses and distribution

yards, as well as the Seabank 1 & 2 generating station adjacent to the Proposed


May 2014 Page 11-30

Development Site; however these are not considered sensitive to construction

dust.

11.5.2. Prior to the main construction works, enabling works will be undertaken, which

will include the ground levelling work, the diversion of utilities, and the land

raising of the Generating Station site.

11.5.3. The potential impacts considered at the sensitive receptor locations are:

• Effects on amenity and property including changes to the rate of

deposition of particulate matter onto surfaces; and

• Changes in 24-hour mean airborne particulate concentrations that might

increase the risk of exposure to PM10 at levels that could exceed the 24-

hour air quality objective.

11.5.4. The significance of impacts on sensitive receptors has been informed by IAQM

Guidance (Ref 11-11). The assessment has assumed that standard construction

dust mitigation measures will be applied onsite, in accordance with the best

practice.

11.5.5. The predicted impacts at the nearest sensitive receptors have been considered

for each of the following activities:

• Earthworks;

• Construction works; and,

• Track-out (the deposition of material on local roads from construction

related vehicle movements).

11.5.6. There are no demolition works anticipated as part of the Proposed Development

scheme.

Earthworks

11.5.7. The earthworks associated with the Proposed Development will entail the storage

and handling of the material imported to Site for the raising of part of the Site for

flood protection, the excavation and handling of material for the diversion of

utilities and the trench for the cooling water pipeline, the earthworks associated

with piling and foundations, and those associated with the final landscaping of the

Site.

11.5.8. Earthworks are generally considered to be a high risk activity with regard to the

generation of dust, due to the mechanical nature of the activities involved and the

manipulation of potentially dusty material. The earthworks undertaken within the

Proposed Development Site boundary will take place within 50m of industrial

receptors and neighbouring agricultural land. The earthworks undertaken for the


May 2014 Page 11-31

installation of the cooling water pipeline will also take place within 50m of

industrial receptors and neighbouring agricultural land, as well as commercial

premises. Of the receptors in close proximity to the works, the car distribution

yard is considered the most sensitive to such impacts and therefore has been

considered further below.

11.5.9. Industry standard dust and particulate mitigation measures will be applied to

control the release of emissions during the earthworks elements of the enabling

and construction works. Such measures are standard practice on all well

managed construction sites and will be implemented through a CEMP to be

prepared by the appointed construction contractor for the works. They may

include, but would not be limited to the following:

• The resurfacing or refilling of earthworked and exposed areas at the

earliest opportunity;

• The provision of a water supply for dust suppression for use during high

risk earthworks activities;

• Ensuring that the slopes of material stockpiles are no steeper than the

natural angle of repose of the material and maintain a smooth profile; and

• Avoiding the double handling of potentially dusty material.

11.5.10. With the implementation of good site practice and the stringent use of dust

control measures throughout the earthworks elements of the enabling and

construction works, based on the IAQM guidance, it is anticipated that there

would be a small, temporary increase in the rate of dust soiling. For the

installation of the cooling water pipeline close to the car distribution yard for

example, the duration of works is envisaged to be less than 4 weeks. Such an

increase is anticipated to have a temporary, reversible, minor adverse effect on

receptors.

Construction

11.5.11. The construction work activities associated with the Proposed Development will

entail the erection of structures for the Generating Station and Peaking Plant.

The construction of these structures will mainly be undertaken using pre-

fabricated materials and there will be a minimal requirement to cut and grind

construction materials onsite.

11.5.12. Industry standard dust and particulate mitigation measures will be applied to

control the release of emissions during the construction works. Such measures

are standard practice on all well managed construction sites and will be

implemented through the CEMP to be prepared by the appointed construction


May 2014 Page 11-32

contractor for the works. These may include, but would not be limited to the

following:

• Any onsite cement batching will be undertaken in a designated area that

where possible is shielded and located away from the most sensitive

receptors nearby;

• Locating potentially dust generating activities away from the most

sensitive receptors nearby, where possible; and,

• The provision of a water supply for suppression for use during high risk

construction activities.


control measures throughout the construction works, it is anticipated that there

would be a negligible impact on the rate of dust soiling and a negligible impact on

short-term concentrations of PM10 and a negligible effect on receptors.

Track-out

11.5.14. During the construction phase, construction-related vehicle movements will

access and leave the Proposed Development Site via a proposed Spine Access

Road which Severnside Distribution Land Ltd is currently constructing under the

extant 1957/58 consent. The new road will connect to the A403.

11.5.15. Access/ egress for the proposed cooling water pipeline corridor is expected at

several locations along the length of the corridor, for example where the pipeline

crosses a road access will be sought from along the affected road.

11.5.16. Based on IAQM guidance, there is the potential for dust associated with track-out

to impact upon sensitive receptors located within 100m of roads that extend up to

500m from the construction site entrance. Receptors within 100m of the new

Spine Access Road include the surrounding industrial premises and nearby

agricultural land.

11.5.17. Standard dust and particulate mitigation measures, as described within current

construction dust guidance, will be applied to control the release of emissions

from track-out during the enabling and construction works. Such measures are

standard practice on all well managed construction sites and will be implemented

through the CEMP to be prepared by the appointed construction contractor for

the works. These measures may include, but would not be limited to the

following:

• The hard-surfacing and effective cleaning of main onsite haul routes and

the enforcement of appropriate site speed limits;


May 2014 Page 11-33

• Routinely cleaning sections of the public road network near to the site

entrance, using wet sweeping methods; and

• Covering or sheeting vehicles entering and leaving the site that are

loaded with potentially dusty material.


control measures throughout the construction works, it is anticipated that track-

out would have a negligible impact on the rate of dust soiling and a negligible

impact on short-term concentrations of PM10; such an impact is anticipated to

have negligible effect on receptors.

Summary

11.5.19. The predicted impact of enabling and construction activities on nearby receptors

during the construction of the Proposed Development are summarised in Table

11-18. Overall the impact of the Proposed Development would result in

negligible effects or temporary, reversible, minor adverse effects for dust

deposition on sensitive receptors.

Table 11-18: Summary of Construction Phase Dust Effects

Source Effects on Amenity and Property Exposure to PM10 at Levels that could Exceed the 24-hr Mean PM10 Air Quality Objective

Demolition N/A N/A

Earthworks Temporary, Reversible, Minor Adverse

Negligible

Construction Negligible Negligible

Track-out Negligible Negligible

Assessment of Construction Road Traffic

11.5.20. The enabling works associated with raising the level of the Proposed

Development Site will increase HDV movements by up to an estimated 342

vehicles per day. Based on DMRB screening calculations, the predicted impact of

the emissions of these vehicle movements to annual mean NOX concentration

and the nitrogen deposition rate at the Severn Estuary habitat site is summarised

in Table 11-20.


May 2014 Page 11-34

Table 11-19: Predicted With-Development NOX Concentrations and Nitrogen Deposition Rates

at the Severn Estuary SAC/SPA/Ramsar/SSSI in 2019

Distance

from A403

(m)

Annual

Mean NOx

(µg/m3)

Change in

Annual Mean

NOx (µg/m3)

Significance

of change in

annual mean

NOx

Nitrogen

Deposition

Rate

(kg N/ha/yr)

Change in N-

Deposition

Rate

(kg N/ha/yr)

North of the Proposed Development Site

25 46.3 +1.4

(<5% Increase) Minor adverse 21.2

+0.04 (<1% Increase)

30 44.4 +1.2



40 41.4 +0.9



50 39.1 +0.7



75 35.3 +0.4



100 33.2 +0.2

(<1%) increase Negligible 20.8


Southwest of the Proposed Development Site

25 31.4 +1.4

(<5% increase) Minor adverse 10.6


30 29.5 +1.2

(<5% increase) Minor adverse 10.5


40 26.5 +0.9

(<5% increase) Negligible 10.4


50 24.2 +0.7



75 20.4 +0.4



100 18.3 +0.2

(<1%) Negligible 10.2


Criteria 30 20 – 30

11.5.21. The peak construction traffic emissions are predicted to lead to a small increase

in annual mean NOX concentrations at the Severn Estuary

SAC/SPA/Ramsar/SSSI within 100m of the A403, with the greatest increases at

locations within 25m of the A403. It is important to note that this is based on an

assessment of annual impact against annual assessment criteria, whereas the

importation of material for land raising is expected to only last for a period of six

months. The assessment is therefore an overestimate of potential impact.

11.5.22. As outlined above, the Severn Estuary SAC/SPA/Ramsar/SSSI is already

predicted to experience concentrations of NOX in excess of the CLPVE to the


May 2014 Page 11-35

north of the Proposed Development in 2019, with or without the Proposed

Development. The increase as a result of the Proposed Development

construction traffic is therefore considered a minor adverse effect at this

location. However locations to the west and southwest are predicted to

experience annual mean NOX concentrations well below the CLPVE and

therefore the increase is considered to have negligible effect for all but those

locations within 30m of the A403. The impacts from construction traffic will be

temporary and therefore the effect of the increased NOX is considered to be

temporary and reversible.

11.5.23. The rate of nitrogen deposition will also increase as a result of the construction

vehicle movements associated with the enabling works. With this increase,

assuming the baseline is at the maximum and average deposition rates reported

for this habitat for locations north and southwest of the Site respectively, the rate

of deposition remains well below the upper threshold of the critical load for this

habitat. The effect of increased nitrogen deposition at the Severn Estuary

SAC/SPA/Ramsar/SSSI as a result of construction traffic is therefore considered

to be negligible.

11.5.24. The enabling works are scheduled to last for a period of approximately 12

months, with the vehicle trips associated with land raising assumed to be

compressed into a 6 month period. Upon completion of those works, construction

traffic will fall to levels of around 80 HDV movements per day. As such, the

annual mean NOX concentrations reported in Table 11-19 represent a worst-case

period and concentrations will fall closer to baseline levels on completion of the

earthworks associated with the enabling works.

11.5.25. A screening assessment has been undertaken to estimate the impact of

construction traffic on human air quality sensitive receptors located adjacent to

the A403 and the A4. The DMRB Screening Method Spreadsheet was used to

predict the road NOX and PM10 contributions to annual mean concentrations at a

location 10m from the centreline of the road, which is representative of the

nearest sensitive receptors locations to the A403 and the A4. The road NOX

contribution was then converted into an annual mean road NO2 contribution using

Defra’s NOX to NO2 conversion spreadsheet.

11.5.26. The 342 HDV movements associated with the land raising element of the

enabling works would increase annual mean concentrations of NO2 by 1.6µg/m3

and annual mean concentrations of PM10 by 0.2µg/m3 at the worst affected

residential receptors. Such an increase in pollutant concentrations, on top of the

baseline concentrations described in Section 11.4, would lead to an impact of low

magnitude in an area where air quality is well below the NAQS objectives for

those pollutants. The proportion of particulate matter emissions that are PM2.5 is


May 2014 Page 11-36

included within the PM10 contribution of 0.2µg/m3. An increase of less than

0.2µg/m3 in an area where background concentrations are well below the NAQS

objective is considered to be insignificant. The effect of such impacts is therefore

considered to be negligible.

11.5.27. The impact of HDV movements on the AQMA at Avonmouth Road has been

assessed assuming as a worst-case that all HDVs use this route. In reality, the

HDVs are more likely to use the A4/Portway. The predicted concentrations at the

receptor distances are shown in Table 11-20 below. The change in annual mean

NO2 for each assessment location is low, and the predicted concentration with

construction traffic is less than 30µg/m3 for each location. The effect of increased

NO2 concentration as a result of construction traffic at the AQMA receptors is

therefore considered to be negligible.

Table 11-20: Maximum Annual Mean NO2 at AQMA Receptors

Receptor Distance from A’mouth Road

NO2 Concentrations (µg/m3)

Change in Annual Mean NO2 (µg/m

3)

Significance of Change Diffusion

Tube1

2012

Baseline2

2012

Do-Minimum 2019

With-Development construction traffic 2019

8m 34.7 34.4 28.0 28.6 +0.6 (<5% Increase)

Negligible

10m 34.0 34.1 27.7 28.3 +0.5 (<5% Increase)

Negligible

15m 31.8 33.3 27.1 27.6 +0.5 (<5% Increase)

Negligible

1 BCC 2012

2 With DMRB calculated traffic contribution

Operational Phase

Assessment of Point Source Emissions

11.5.28. The impact of point source emissions on human health receptors has been

determined from isopleth figures of pollutant dispersion and maximum model

output at discrete receptor locations. The maximum hourly, daily and annual

average predicted concentrations have been compared with the NAQS

objectives, as summarised in Tables 11-21 and 11-22 below.

11.5.29. These results represent the output from the worst-case modelled scenario

described in Table 11-4, which is Scenario C (i.e. 2 x 580MWe single-shaft

CCGTs and 240MWe of reciprocating diesel engines). Variation in the predicted

results with alternative Rochdale Envelope scenarios is presented in Appendix F,

Volume II of this PEI Report.


May 2014 Page 11-37

11.5.30. The following abbreviations are used in Tables 11-21 and 11-22:

• PC: This is the Process Contribution and represents the change caused

by the Proposed Development; and

• PEC: This is the Predicted Environmental Concentration and is PC plus

background concentration. It is the concentration expected at a particular

receptor once the effect of the Proposed Development is taken into

account.

Table 11-21: Maximum NO2 Predicted Concentrations at Human Health Receptors

Sensitive

Receptor

2019 NO2

Baseline1

(µg/m3)

Annual

Mean NO2

PC (µg/m3)

Magnitude of

Change

Annual

Mean PEC

(µg/m3)

Significance

of Effect

1 18.1 0.4 Low

(<5% Increase) 18.5 Negligible

2 18.1 0.3 Very Low

(<1% Increase) 18.4 Negligible

3 18.1 1.4 Low 19.5 Negligible



6 18.1 0.1 Very Low 18.2 Negligible





112

35.0 0.1 Very Low 35.1 Negligible

122

35.0 0.2 Very Low 35.2 Negligible

1. 2019 baseline used for opening year as a conservative assumption

2. R11 (Cribbs Causeway AQMA) and R12 (Avonmouth AQMA) baselines are taken from

most recent LA diffusion tube monitoring (2012) at these locations as worst-case

assumption.

Table 11-22: Maximum Predicted Concentrations at Worst Affected Human Health

Receptor

Pollutant Averaging

period

Process

Contribution

PC (µg/m3)

PC/ NAQS

Threshold for very

low change (%

NAQS)

Significance

of Effect

NO2 1-Hour mean

(99.8th %ile)

13.91

6.9% <10% Negligible


May 2014 Page 11-38

Pollutant Averaging

period

Process

Contribution

PC (µg/m3)

PC/ NAQS

Threshold for very

low change (%

NAQS)

Significance

of Effect

PM10 24-Hour mean

(90.4th %ile)

1.02

2.0% <10% Negligible

PM10 Annual mean 0.23 0.5% <1% Negligible

1. PROW, 1km S of Proposed Development

2. PROW, 2km NE of Proposed Development

3. Easter Compton residences

11.5.31. The maximum process contribution of NO2 from any of the operational scenarios

results in a low change in the annual mean concentration at four of the identified

receptors. The ambient concentration at these receptors is well below the

objective with the Proposed Development, therefore the significance of the effect

at these receptors is predicted to be negligible. The magnitude of change at all

other human health receptors is very low and the significance of effect is also

negligible.

11.5.32. The magnitude of change in annual mean NO2 concentration at the identified

AQMAs (represented by receptors R11 and R12) from the Proposed

Development is very low, therefore the significance of effect at the AQMAs is


11.5.33. The maximum short-term predicted concentration of NO2 at the worst affected

receptor (the PROW immediately south of Proposed Development) represents

6.6% of the daily mean NAQS objective and therefore is considered to be a very

low change. The Proposed Development short term contribution to hourly mean

NO2 is considered to have a negligible effect on human health receptors.

11.5.34. The maximum short-term and long term process contributions of PM10 at the

worst affected receptors represent very low changes in the mean concentration

over the appropriate averaging periods and therefore the Proposed Development

operational contribution of PM10 is considered to have negligible effect on

human health receptors.

11.5.35. The impact of point source emissions on sensitive ecological receptors has been

determined from isopleth figures of pollutant dispersion and maximum model

output at specified points. The maximum daily average and annual average

predicted concentrations have been compared with the CLPVEs, as summarised

in Table 11-23 below.


May 2014 Page 11-39

Table 11-23: Maximum Predicted Concentrations of NOX at Statutory Ecological Receptors

Receptor Location

Annual mean predicted NOx

concentration

Maximum daily mean predicted NOx

concentration

PC

(µg/m3)

as % of

CLPVE Sig.

PC

(µg/m3)

as % of

CLPVE

Sig.

Severn Estuary (Atlantic salt marshes)

North 0.29 <1% Negligible 10.8 14%

Minor Adverse

West 0.17 <1% Negligible 6.0 <10% Negligible

Southwest 0.28 <1% Negligible 11.3 15% Negligible

Horseshoe Bend 0.13 <1% Negligible 3.7 <10% Negligible

Avon Gorge 0.12 <1% Negligible 2.7 <10% Negligible

Bushy Close 0.10 <1% Negligible 3.0 <10% Negligible

Gwent Levels – Magor and Undy

0.11 <1% Negligible 3.0 <10% Negligible

River Wye 0.15 <1% Negligible 2.0 <10% Negligible

Nedern Brook Wetlands, Caldicot

0.08 <1% Negligible 2.0 <10% Negligible

Weston Big Wood 0.14 <1% Negligible 2.1 <10% Negligible

Ashton Court 0.10 <1% Negligible 2.4 <10% Negligible

Weston-In-Gordano 0.13 <1% Negligible 1.9 <10% Negligible

11.5.36. The Proposed Development annual average contribution of NOX at all assessed

ecological receptors is predicted to be below the EA EPR threshold for

insignificance (<1%) for annual mean critical levels, representing changes of very

low magnitude at these receptors. The significance of effects of NOX emissions

on these receptors is therefore considered to be negligible.

11.5.37. The maximum contribution to the north of the Proposed Development occurs in

an area which is already exposed to baseline NOX above the CLPVE, at

30.7µg/m3, however as the contribution is <1%, and therefore considered very

low, the very low change represents a negligible effect on the Severn Estuary

SAC/SPA/Ramsar/SSSI at this location.

11.5.38. The maximum impact from the daily mean process contribution is predicted to the

southwest of the Proposed Development, resulting in a daily mean predicted

environmental concentration (PEC) of 11.3µg/m3, or 15% of the CLPVE. The

annual average background at this location is 15.8µg/m3, and it is usual to double

this when assessing short term (typically hourly) impacts, however as the CLPVE

is a daily average, this is not considered appropriate, as a daily average would be

likely to be below this value. Even when this approach is used, the CLPVE would

not be exceeded, with a predicted environmental concentration representing 57%


May 2014 Page 11-40

of the daily CLPVE. It is considered unlikely that the maximum process

contribution would result in exceedance of the daily mean at this location.

11.5.39. To the north of the Proposed Development the daily mean process contribution

represents 14.4% of the CLPVE. The annual average background concentration

at this location is much higher, at 30.7µg/m3, and therefore when this is doubled,

the PEC represents 96% of the CLPVE. As stated above, it is considered an over

estimate to use this approach for daily impacts, however even taking into account

this conservative assumption the effect is only predicted to be minor adverse,

due to the high background concentration.

11.5.40. The dispersion modelling includes a number of conservative assumptions in

combination, including:

• Use of the worst-case year of meteorological data;

• Maximum building sizes within the assessed Rochdale Envelope;

• Worst case CCGT configuration within the assessed Rochdale Envelope,

other configurations resulted in lower predicted impacts as shown in

Appendix F, Volume II of this PEI Report.

• Annual operation of 100% for both CCGT main plant units (8,760 hours

per year, compared with estimated 2,716 hours per year) and peaking

plant at maximum operation (1,500 hours per year);

• Operation of the plant at IED emission limits, when typical operational

concentrations for the Seabank 1 & 2 CCGTs are demonstrably

approximately half this value; and

• Conservative estimates of background concentrations at the sensitive

receptors.

11.5.41. For comparison, the dispersion model has also been run assuming the expected

actual annual operating hours of the CCGT units (2,716) and the resulting

process contributions at ecological receptors are presented in Table 11-24 below.

Table 11-24: Maximum Predicted Concentrations of NOX at Statutory Ecological Receptors –

Typical Operating Hours

Receptor Location


concentration

Maximum daily mean predicted

NOx concentration

PC

(µg/m3)

as % of

CLPVE Sig.

PC

(µg/m3)

as % of

CLPVE

Sig.

Severn Estuary

North 0.11 <1% Negligible 4.7 <10% Negligible

West 0.07 <1% Negligible 2.7 <10% Negligible


May 2014 Page 11-41

Receptor Location


concentration

Maximum daily mean predicted

NOx concentration

PC

(µg/m3)

as % of

CLPVE Sig.

PC

(µg/m3)

as % of

CLPVE

Sig.

(Atlantic salt marshes)

Southwest 0.10 <1% Negligible 4.5 <10% Negligible

11.5.42. It can be seen that when the assessment is carried out at more realistic

operational levels that all the process contributions to the daily CLPVE are all

below the 10% threshold for insignificance for short term impacts.

11.5.43. As discussed above the coastal salt marshes are not listed as sensitive to NOX in

the atmosphere; taking into account the worst-case assumptions made in the

selection of dispersion model parameters the effect of additional operational

contributions on species present at this location may be considered negligible.

11.5.44. The impact of deposited nutrient nitrogen on the Severn Estuary

SAC/SPA/Ramsar/SSSI as a result of the maximum process contribution based

on 100% operation is shown in Table 11-25 below.

Table 11-25: Maximum Predicted Nutrient Nitrogen Deposition at Statutory

Ecological Receptors

Site Critical Load Range (kg N/Ha/year)

Predicted N deposition (kg N/Ha/year)

Predicted deposition as % of lower load

Significance

Severn Estuary (Atlantic salt marshes)

20-30 0.041 <1% Negligible

11.5.45. The most sensitive habitat within the Severn Estuary SAC/SPA/Ramsar/SSSI to

nutrient nitrogen deposition is listed as the Atlantic salt marshes, which are

present along Chittening Warth within 400m of the Proposed Development. The

maximum predicted nitrogen deposition resulting from operational emissions at

any location within the designated site is less than 1% of the lower critical load

defined for this habitat type and therefore the effect of operational emissions on

this habitat are considered to be negligible. No eutrophication impacts are

anticipated due to this negligible increase in nutrient deposition.

11.5.46. The Severn Estuary SAC/SPA/Ramsar/SSSI is designated for a number of

species that are potentially sensitivity to acidity, however no critical levels are

published for these species and therefore no quantitative assessment of acid

deposition as a result of operational emissions has been made.


May 2014 Page 11-42

11.6. Residual Effects and Conclusions

Construction

11.6.1. The air quality assessment of construction impacts has assumed that the

measures outlined within the embedded mitigation section would be incorporated

into the design and construction management procedures of the Proposed

Development, as they are standard best practice measures that are routinely

applied across UK construction sites. No specific additional mitigation has been

identified as necessary for the construction phase of the Proposed Development.

For this reason, the residual effects would be as reported within the Potential

Effects section of this chapter. A summary of residual effects is provided in Table

11-29.

Operation

11.6.2. The air quality assessment of operational impacts has assumed that the IED

ELVs will be met for the operational plant in accordance with use of BAT under

the environmental permitting regime. No specific additional mitigation has been

identified as necessary for the operational phase of the Proposed Development.

For this reason, the residual effects would be as reported within the Potential

Effects section of this chapter. A summary of residual effects is provided in Table

11-26.

Decommissioning

11.6.3. Consistent with construction mitigation, it has been assumed that relevant best

practice dust mitigation measures would be in place during any decommissioning

works. No specific additional mitigation has been identified as necessary for the

decommissioning phase of the Proposed Development.


May 2014 Page 11-43

Table 11-26: Summary of Significant Effects and Mitigation

Development Stage

Effect Without Mitigation

Significance of Effect Without Mitigation

Mitigation

Significance of Effect With Mitigation (Residual Effect)

Nature of Effect

Exhaust emissions associated with HDV movements during the enabling and construction programme

No significant impacts are anticipated prior to mitigation

Assessments include standard mitigation measures or BAT and therefore no unmitigated significance has been evaluated

The implementation of the mitigation measures outlined in the CEMP will minimise the release of pollutants

Negligible Temporary

Exhaust emissions from construction site plant

No significant impacts are anticipated prior to mitigation




Construction dust

Elevated emissions of particulates to air




Point source emissions associated with the operational development

Elevated emissions to air from stack emissions


The implementation of BAT and embedded mitigation by design will minimise emissions to air

Negligible Permanent


May 2014 Page 11-44

11.7. Cumulative Effects Assessment


infrastructure in combination with other developments in the area, as outlined in

Chapter 7: Assessment Methodology.

11.7.2. There are no cumulative traffic and point source effects from the Proposed

Development as traffic impacts will occur during construction, while point source

impacts will occur during plant operation.

11.7.3. A number of cumulative schemes are identified in Chapter 7: Assessment

Methodology, of which preliminary modelling has demonstrated only two have the

potential to create cumulative effects on air quality with the Proposed

Development, as discussed below.

11.7.4. The Severnside Energy Recovery Centre and Avon Power Station consented

schemes are sufficiently close to the Proposed Development and of sufficient

scale to have the potential to contribute to cumulative impact on identified

receptors; these have been modelled together with predicted emissions from the

Proposed Development to determine the overall potential impact. Where data is

unavailable for the cumulative consented scheme, representative estimates have

been made. A summary of the modelled data used in this assessment is provided

in Table 11-27. It should be noted that the Seabank 1 & 2 generating station is

already operational and its effects are therefore assumed as being captured

within the baseline data used in the assessment.

11.7.5. The typical operational scenario (2,716 hours/year) has been assumed for the

Proposed Development for assessment of realistic worst-case long term effects.

Table 11-27: Modelled Input Parameters – Cumulative Effects Assessment

Parameter

SITA (32MW) –

Single Stack

Avon Power

(1200MW) – Each of

2 stacks

Stack Height (m) 126 100

Efflux Velocity (m/s) 15 44

Emission Temperature (°C) 150 80

Volumetric Flow (Nm3/hr)

250,000 3,408,000

Volumetric Flow at stack exit

parameters (Am3/hr)

110 865

Flue Diameter (m) 3.0 5


May 2014 Page 11-45

Parameter

SITA (32MW) –

Single Stack

Avon Power

(1200MW) – Each of

2 stacks

Assumed maximum operating hours /

year 8,760 8,760

NOx ELV (IED, mg/Nm3) 200 30

Assumed stack location 353750, 182750 354200,182800

354250,182790

11.7.6. The predicted concentrations from cumulative source modelling indicate that the

additional contributions from the Proposed Development are unlikely to result in

exceedance of hourly or annual mean NAQS objectives at the worst-affected

human health receptors (Marsh Common, Severn Beach residences).

11.7.7. The predicted concentrations from cumulative source modelling indicate that the

additional contributions from the Proposed Development would result in a low

change in annual mean NO2 at the worst-affected area of the Severn Estuary

SAC/SPA/Ramsar/SSSI (north of the Proposed Development Site) where the

baseline is already anticipated to be in exceedance of the CLPVE. The

cumulative impact of the combined emissions would therefore lead to a minor

adverse impact in this location.

Table 11-28: Cumulative Assessment: Maximum Predicted Concentrations

Pollutant Averaging

period

NAQS2

(µg/m3)

Cumulative

Contribution

(CC, µg/m3)

CC/

NAQS2

AC

(µg/m3)

PEC/NAQS2

NO2

1-Hour

mean

(99.8th %ile)

200 10.5 5.3% 36.2 23%

NO2 Annual

mean 40 1.5 4.9% 18.1 49%

NOx as

NO2 Daily mean 75 9.4

1 12.5% 70.8

1 94%

NOx as

NO2

Annual

mean 30 0.3

1 1.1% 30.7

1 103%

1. Assuming northern receptor location

2. NAQS or CLPVE as relevant

11.7.8. The above cumulative assessment takes into account a number of conservative

assumptions as outlined in Section 11.5.40.


May 2014 Page 11-46

11.7.9. It is considered that the above assumptions lead to a worst-case assessment of

potential cumulative effects at human health and ecological receptors as a result

of the combined consented schemes with additional worst-case contributions

from the Proposed Development. As such the cumulative impacts are expected

to result in a minor adverse effect at the Severn Estuary

SAC/SPA/Ramsar/SSSI as a worst-case.



design may be subject to refinement prior to submission of the final DCO

application. Any changes that lead to differing or new impacts and effects will be

highlighted within the final ES, along with the reasons for the change.


preparation of this PEI Report and the final ES; air quality conditions are dynamic

and evolve over time. The Proposed Development Site is currently subject to

excavation, top soil stripping, and levelling in certain areas in order for third

parties to deliver the Spine Access Road and new channel for the Red Rhine,

which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7:

Assessment Methodology. A haul road is also being constructed through the

middle of the Proposed Development Site to enable access by third party from

the roundabout to the east of the Site to the Severnside Energy Recovery Centre

to the west. These works onsite are being undertaken by other developers, under

extant planning permissions and are separate to the Proposed Development.





11.8.4. The significance of effects of point source emissions on ecological receptors,

through deposition of nutrient nitrogen or acidity, has been evaluated using the

EA insignificance criterion of 1% of the long term critical level objective, as

above. At this stage no evaluation of contribution to critical loads has been

undertaken; the need for this will be considered following the Stage 2

consultation, and if required, included in the final ES.

11.8.5. Monitoring data from the automatic and non-automatic sites in the area were

presented in Table 11-12 for 2012 (the most recent year’s ratified data available

at the time of writing). This secondary baseline data will be updated for the final

ES, although it is not intended that further diffusion tube monitoring will be

undertaken.


May 2014 Page 11-47

11.9. References

Ref. 11-1 Environmental Protection. The Air Quality Standards Regulations

2010 No.1001; The National Archives; 2010

Ref. 11-2 European Directive on Ambient Air Quality 2008/50/EC

Ref. 11-3 European Fourth Daughter Directive on Ambient Air Quality

2004/107/EC

Ref. 11-4 UK Environment Act 1995; reviewed 2007

Ref. 11-5 European Directive on Industrial Emissions 2010/75/EU

Ref. 11-6 Integrated Pollution Prevention and Control Reference Document on

the Best Available Techniques for Large Combustion Plant; European

Commission 2006

Ref. 11-7 UK Environmental Permitting (England and Wales) Regulations 2010

(EPR) (as amended)

Ref. 11-8 Environmental Permitting Regulation Horizontal Guidance,

Environmental Risk Assessment, Annex F – Air Quality; Environment

Agency; 2011

Ref. 11-9 Design Manual for Roads and Bridge (DMRB), Volume 11

Environmental Assessment, Section 3 Environmental Assessment

Techniques, Part 1, HA207/07 Air Quality; Highways Agency; 2007

Ref. 11-10 NPPF Technical Guidance; Department for Communities and Local

Government, 2012

Ref. 11-11 Guidance on the Assessment of the Impacts of Construction on Air

Quality and the Determination of their Significance; Institute of Air

Quality Management; 2011

Ref. 11-12 Control of Dust from Construction and Demolition Activities; Building

Research Establishment; 2003

Ref. 11-13 Development Control: Planning for Air Quality (2010 Update); Update

guidance from Environmental Protection UK on dealing with air

quality concerns within the development control process; EPUK; 2010

Ref. 11-14 LAQM TG(09)

Ref. 11-15 http://laqm.defra.gov.uk/review-and-assessment/tools/background-

maps.html; DEFRA; Accessed February 2014

Ref. 11-16 AQTAG06 Environment Agency; 2011


May 2014 Page 11-48

Ref. 11-17 Site Relevant Critical Loads and Source Attribution; Centre for

Ecology and Hydrology; Available from: http://www.ceh.ac.uk

Accessed February 2014.

Ref. 11-18 Atmospheric Dispersion Modelling System (ADMS) User Guide;

Cambridge Environmental Research Consultants Ltd; 2012

Seabank 3 PEI Report – Chapter 12 Noise and Vibration

May 2014 Page 12-1

12. Noise and Vibration

12.1. Introduction

12.1.1. This chapter provides an assessment of noise and vibration effects that may

occur during the construction, operational and decommissioning phases of the


12.1.2. The aims of this chapter are to:

• Determine the existing noise climate at the nearest sensitive receptors to

the Proposed Development;

• Assess the likely noise and vibration effects from the enabling works and

construction activities, operation, and decommissioning of the Proposed

Development;

• Assess the offsite noise effects associated with any increases in road

traffic flows as a result of the Proposed Development; and

• Recommend noise mitigation measures, if required.

12.1.3. Details of noise terminology and theory relevant to this report are presented in

Appendix G Part 1, Volume II of this PEI Report.

Consultation



methodology and content of this chapter. A summary of stakeholder comments

and how they have been incorporated into this PEI Report chapter are provided

in Table 12-1.

Table 12-1: Scoping Opinion Responses Relevant to Noise and Vibration



Information should be provided on the types of vehicles and plant to be used during the construction phase, whilst noise generated during operation should also be identified and assessed.

See section 12.5 of this chapter and Appendix G Part 3, Volume II of this PEI Report.

Construction noise and vibration impacts on people should be assessed, including any potential for disturbance at night, at weekends and other unsocial hours.


Noise and vibration impact along the foreshore and within watercourses in/near the site should be addressed.


The study area should extend to potential noise impacts off site.



May 2014 Page 12-2


Consideration should be given to monitoring noise complaints during construction and when the development is operational.


NE

NE suggests that the influence of terrain and prevailing winds need to be incorporated into the methodology when mapping sound 'contours'.


With the development potentially being phased over 3 years, it is important to consider the seasonal impacts of the development and avoid noisy or disruptive activities in sensitive areas, for example laying pipes in winter months across known wintering bird habitat.

See section 12.5 of this chapter for predicted noise levels and Chapter 16: Ecology for an assessment of the effect on habitats and species.

SGC

It is recommended that baseline noise monitoring should be undertaken further North of Elmtree Farm. This would be around the Marsh Common area and would include properties such as Gilslake.


With regards to the operating noise level our aim would be to achieve a 0 decibel (dB) increase above existing background rather than +5dB. If this cannot be achieved then we would seek reasons as why this is the case and therefore consider if a +5dB would be acceptable in this case based on the number of nearby residential properties.

See sections 12.1 and 12.5 of this chapter.

BCC Agreed to the same operating noise level criterion as SGC. No further comments were received.

-

12.1.5. Further consultation took place with the Environmental Health Officers at SGC

and BCC in May 2013 (documented by email) regarding the measurement and

assessment methodologies following receipt of the Scoping Opinion. The

following were agreed:

• Long-term and short-term noise monitoring locations, as described later

in this chapter;

• Monitoring protocol (noise levels to be logged in contiguous 15 minute

intervals at long-term locations, and one hour intervals during the day

and five minute intervals during the night at short-term locations);

• Construction noise effects to be assessed using the ABC method in

BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and Vibration

Control on Construction and Open Sites’ (Ref. 12-1); and

• Operational noise impacts to be assessed using BS 4142: 1997 'Method

for rating noise affecting mixed residential and industrial areas' (Ref. 12-

2). The Rating Level should aim to be 0dB above the background noise


May 2014 Page 12-3

level, although a Rating Level of 5dB above the background level may be

satisfactory depending on the number of sensitive receptors affected.

Legislation and Planning Policy

12.1.6. Appendix D, Volume II of this PEI Report presents a summary of the planning

policy relevant to this chapter.

12.1.7. Other guidance that is applicable to this assessment is outlined below.

• British Standard (BS) 5228: 2009+A1: 2014 ‘Code of Practice for Noise

and Vibration Control on Construction and Open Sites’. Noise and

vibration levels generated by construction activities are regulated by

guidelines and are subject to local authority control. No UK national noise

limits exist for construction noise. However, guidance on acceptable

noise levels is provided by this BS.

• World Health Organisation (WHO) Guidelines (Ref. 12-3). With regard to

daytime levels in outdoor areas, e.g. rear gardens, over the 16-hour

daytime period (7.00am – 11.00pm) the WHO Guidelines state “few

people are highly annoyed at LAeq levels below 55dB(A)”. This guideline

is commonly used as an upper level for gardens. The WHO Guidelines

also provide criteria for individual noise events at night. It advises that

LAmax,fast levels inside bedrooms should not regularly exceed 45dB, and if

occupants are to use open windows for ventilation, external levels should

not regularly exceed 60dB LAmax,fast (this assumes a 15dB reduction

through a partially open window).


Construction Noise


12.2.1. Construction noise and vibration levels have been predicted using the

methodology given in BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and

Vibration Control on Construction and Open Sites’. This includes enabling works,

which will pre-empt the main construction activities and are assumed to be less

noisy than the later phases of work onsite.

12.2.2. Noise levels experienced by local receptors during construction depend upon a

number of variables, the most significant of which are:

• The noise generated by plant or equipment used on site, road traffic and

other sources, generally expressed as sound power levels (Lw);

• The periods of use of the plant on site, known as its on-time;


May 2014 Page 12-4

• The distance between the noise source and the receptor;

• The attenuation due to ground absorption, air absorption and barrier

effects; and

• In some instances, the reflection of noise due to the presence of hard

surfaces such as the sides of buildings.

12.2.3. Specific details of construction works will not be available until after receipt of the

DCO and during detailed design of the Proposed Development. Therefore,

representative construction activities and worst case assumptions have been

assumed based on experience of similar projects.

12.2.4. Sound power levels for each piece of equipment for each construction activity

have been sourced from BS 5228 ‘Control of noise on construction and open

sites’ (Part 1), which provides measured noise levels for various items of

construction plant. The source data input into the calculation spread sheets are

provided in Appendix G Part 3, Volume II of this PEI Report.

12.2.5. The following major activities have been assumed during the enabling works and

construction of the Proposed Development:

• Site clearance;

• Earthworks;

• Piling (bored);

• Excavation and foundations;

• Slab construction;

• Steelwork construction;

• Services and fitting; and

• Access/on-site road and car parking construction.

12.2.6. It is anticipated that the construction works within the Other DCO Land, which

includes the laying of the cooling water pipeline and installation of the electrical

cable, will comprise:

• Site clearance;

• Earthworks;

• Excavation and foundations;

• Laying of the pipeline / construction of the cable rack; and

• Backfill.


May 2014 Page 12-5


12.2.7. BS 5228 contains a methodology for the assessment of the significance of effect

of construction noise in relation to the ambient noise levels at nearby residential

dwellings, known as the ABC method. The thresholds provided in BS 5228-1:

2009+A1: 2014 are reproduced below in Table 12-2.

Table 12-2: Construction Noise Thresholds at nearby Residential Dwellings

Assessment Category Threshold Value (dB) (LAeq,T)

Category A A)

Category B B)

Category C C)

Night-time (11.00pm – 7.00 am) 45 50 55

Evenings and weekends D)

55 60 65

Daytime (7.00am – 7.00pm) and Saturdays (7.00am – 1.00pm)

65 70 75

NOTE 1: A potential significant effect is indicated if the total LAeq noise level arising from the site exceeds the threshold value for the category appropriate to the ambient noise level.

NOTE 2: If the ambient noise level exceeds the Category C threshold values given in the table (i.e. the ambient noise levels is higher than the above values), then a potential significant effect is indicated if the total LAeq,T noise level for the period increases by more than 3dB due to site noise.

NOTE 3: Applies to residential receptors only. A)

Category A: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are less than these values. B)

Category B: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are the same as Category A values. C)

Category C: Threshold values to use when ambient noise levels (when rounded to the nearest 5dB) are higher than Category A values. D)

7.00pm –11:00pm weekdays, 1:00pm – 11:00pm Saturdays, 7:00am – 11pm Sundays.

12.2.8. For the appropriate period (night, evening/weekend, day), the ambient noise level

is rounded to the nearest 5dB. The appropriate assessment category is

established and the total predicted construction noise level is then compared with

this Threshold Value. If the predicted total noise level exceeds the Threshold

Value, then a significant effect is deemed to occur.

12.2.9. The criteria shown in Table 12-3 have been used to assess the significance of

construction noise levels, modified to be consistent with the methodology used in

this PEI Report which categorises significance in terms of Negligible, Minor,

Moderate or Major effects (beneficial or adverse). For the purpose of this

assessment moderate and major effects are assumed to be ‘significant’.


May 2014 Page 12-6

Table 12-3: Significance Criteria for Construction Noise

Construction Noise Level above Threshold Value at the façade (dB)

Magnitude of Change Significance of Effect

<1 None to Slight Negligible (adverse)

1>3 Minor Minor adverse

3>5 Moderate Moderate adverse

5+ Major Major adverse

Construction Vibration


12.2.10. The limit of human perception to vibration is of the order of 0.15 millimetres per

second (mm/s) to 0.3mm/s peak particle velocity (ppv), in the frequency range

0.1 hertz (Hz) to 1500Hz.

12.2.11. The human body is not equally sensitive to all frequencies of vibration and

therefore weighting curves to reflect the frequency dependency of the body have

been developed and are provided within international (ISO) Standards. The

weighting gives a good correlation between the measured vibration level and the

subjective feeling or impact produced by the vibration.

12.2.12. Ground vibrations may cause reactions ranging from ‘just perceptible’ through

‘concern’ to ‘alarm’ and ‘discomfort’. The subjective response varies widely and is

a function of situation, information, time of day and duration.

12.2.13. BS 5228: Part 2 provides historic measured vibration levels for various piling

methods. For example indicative vibration levels for impact bored piling are a ppv

of 7.1mms-1 when measured at 3m, a ppv of 2.3mms-1 at 5.5m and a ppv of

0.9mms-1 at 10m. This clearly demonstrates how quickly vibrations reduce with

distance. Vibration from other methods of piling, such as bored piling or

continuous flight auger (CFA) piling will produce much lower levels of vibration.


12.2.14. The predicted ppv levels are compared to the guidance levels in Table B.1 in

BS 5228, 2009 (reproduced as Table 12-4), to identify the likelihood of complaint.

The category for ‘neutral’ and ‘negligible’ effects has been merged to be

consistent with the methodology adopted for this PEI Report.


May 2014 Page 12-7

Table 12-4: Guidance Effects of Vibration for Human Response (from BS 5228: Part 2: 2009)

Vibration Level mm/s

Impact Significance of Effect

0.14 - 0.3 Vibration might be just perceptible in the most sensitive situations for most vibration frequencies associated with construction at 0.14mm/s. At lower frequencies, people are less sensitive to vibration

Vibration might be just perceptible in residential environments at 0.3mm/s

Negligible (adverse)

0.3-1.0 It is likely that vibration of this level in residential environments will cause complaint, but can be tolerated if prior warning and explanation has been given to residents.

Minor adverse

1.0-10 Vibration is likely to cause complaints regardless of prior warning and explanation.

Moderate adverse

10.0 Vibration is likely to be intolerable for any more than a brief exposure to this level.

Major adverse

Operational Noise


12.2.15. A noise propagation model has been developed in the SoundPLAN suite of

programs to assess the Proposed Development. SoundPLAN implements ISO

9613-2: 1996 ‘Attenuation of sound during propagation outdoors’ (Ref. 12-4).

12.2.16. The model consists of a detailed three dimensional representation of the

Proposed Development and its surroundings. It assumes that the prevailing wind

direction is always from source to receiver, which is likely to overestimate the

noise effect associated with the Proposed Development. It has been employed to

calculate noise levels at surrounding sensitive receptors due to noise breakout

from the proposed buildings and noise emission from external sources.

12.2.17. All significant topographical detail and buildings that may influence the

transmission of noise to affected receptors are included in the noise model. A

digital terrain model, created using ground elevation contours has been used to

position buildings and other noise sources at the correct height. Local structures

offsite that have been included in the model include Seabank 1 & 2 and the

Avonmouth LNG Storage Facility.

12.2.18. BS 4142: 1997 'Method for rating noise affecting mixed residential and industrial

areas' details a method of rating the acceptability of the noise from fixed plant

(electricity substations, pumps, generators, etc.) in existing or proposed

developments such as power stations, factories and commercial/industrial units.

12.2.19. The basis of the standard is a comparison between the background noise level in

the vicinity of residential locations and the specific noise level (adjusted for


May 2014 Page 12-8

characteristic features) of the noise source under consideration. The relevant

parameters in this instance are as follows:

• Background Noise Level - LA90,T - defined in the Standard as ‘the ‘A’

weighted sound pressure level at the assessment position without the

industrial source operating, which is exceeded for 90% of the given time

interval, T, measured using time weighting F (fast);

• Specific Noise Level - LAeq,Tr - the equivalent continuous ‘A’ weighted

sound pressure level of the source in question over a given time interval;

and

• Rating Level - LAr,Tr - the specific noise level plus any adjustment made

for the characteristic features of the noise.

12.2.20. A correction of +5dB is made to the specific noise level if one or more of the

features noted below is present. Only one +5dB correction is made regardless of

the specific noise level containing one or more of the following characteristics.

• The noise contains a distinguishable, discrete, continuous note (whine,

hiss, screech, hum, etc.);

• The noise contains distinct impulses (bangs, clatters or thumps); or

• The noise is irregular enough to attract attention.

12.2.21. The following assumptions have been made when undertaking the operational

noise predictions to ensure a robust assessment:

• The Proposed Development will operate at full load, 24 hours a day and

will comprise 240MW of peaking plant and 1,160MW of CCGT (a total of

1,400MW);

• The cooling method employed for the Proposed Development is hybrid

cooling water system;

• The cladding to be applied to all buildings will be single skin;

• A 5dB correction has been applied to account for any noise

characteristics, such as a hum or whine, as explained above; and

• The facility will be designed to meet the noise levels given for

plant/breakout noise used in this assessment.

12.2.22. The predictions have been carried out for both the single-shaft and multi-shaft

configurations, which make slightly different noise contributions to selected

receptors due to the different position of equipment onsite.


May 2014 Page 12-9

12.2.23. The settings used in the noise modelling software and the list of assumptions

used are presented in Appendix G Part 4, Volume II of this PEI Report.


12.2.24. Once any adjustments have been made, the background and the Rating Levels

are compared. The standard suggests that the greater this difference is, the

greater the likelihood of complaints, as follows:

• A difference of around +10dB or more indicates that complaints are

likely;

• A difference of around +5dB is of marginal significance; and

• If the Rating Level is more than 10dB below the measured background

level, this is a positive indication that complaints are unlikely.

12.2.25. The standard specifies a one hour assessment period during the day and a five

minute period at night.

12.2.26. The significance criteria that have been produced for assessing operational noise

are provided in Table 12-5. Moderate and major effects are considered to be

‘significant’.

Table 12-5: Significance Criteria for Operational Noise

Rating Level above Background Level (dB)

BS 4142 Assessment Significance of Effect

≤ -10 Complaints unlikely Negligible (adverse)

-9 to 0 Less than marginal significance

1 to +5 Marginal significance Minor adverse

+6 to +9 Greater than marginal significance

Moderate adverse

≥ +10 Complaints Likely Major adverse

Road Traffic Noise


12.2.27. The Proposed Development will lead to an increase in traffic flows on the local

road network, both during construction and once the Proposed Development is

operational. The assessment focuses on the effect at existing residential

properties located along surrounding affected roads.

12.2.28. The magnitude of the effect of the additional traffic generated by the construction

and operation of the Proposed Development has been assessed by calculating

the potential change in the 18-hour traffic noise levels (LA10,18h) at a selection

of sensitive receptors along affected roads.


May 2014 Page 12-10

12.2.29. The Design Manual for Roads and Bridges (DMRB) (Ref. 12-5), published by the

Highways Agency, requires that an assessment is carried out where changes in

traffic result in noise changes greater than 1dB(A). Assuming that other

parameters (e.g. speed and proportion of HGVs) do not change, this is equivalent

to a change in the road traffic flow of +25% or -20%. This implies that road traffic

flow changes of up to 25% offer no significant effect in environmental noise terms

(assuming that speed and the proportion of HGVs do not change).

12.2.30. The calculations have employed the methodology provided in Calculation of

Road Traffic Noise (CRTN) (Ref. 12-6), which is the standard methodology

adopted in the UK for the calculation of noise levels from road traffic.


12.2.31. The significance criteria employed in this assessment of the significance of

changes in road traffic noise levels during the operation of the development are

provided in Table 12-6. This is taken from Table 3.1 of the DMRB.

Table 12-6: Scheme for Assessment of Changes in Road Traffic Noise Levels

Change in Noise Level (dB) Magnitude of Change Significance of Effect

0 – 0.9 Negligible Negligible (adverse)

1.0 – 2.9 Minor Minor adverse

3.0 – 4.9 Moderate Moderate adverse

5.0+ Major Major adverse

Receptor Locations

12.2.32. Free-field construction and operational noise levels for a typical one hour period

have been predicted at the location of the closest receptors to the proposed

works. These receptors have been chosen as they are representative of the

closest noise sensitive properties in different directions from the Proposed

Development Site. The selected receptors, and their distance from the closest

proposed buildings (i.e. CCGT’s or peaking plants) are:

• R1: Barnacre, Hallen, approximately 1.1km to the southeast of the

Proposed Development Site;

• R2: Elmington Manor Farm, approximately 1.1km to the southeast of the

Proposed Development Site;

• R3: Orchard Cottage, Easter Compton, approximately 1.5km to the east

of the Proposed Development Site;

• R4: 104 Marsh Common Road, Pilning, approximately 2.2km to the

northeast of the Proposed Development Site;


May 2014 Page 12-11

• R5: 2 Severnwood Gardens, Severn Beach, approximately 1.5km to the

north of the Proposed Development Site.; and

• R6: Chittening Warth mudflats, which are part of the Severn Estuary

SAC/SPA/Ramsar/SSSI site, located approximately 400m to the

northwest of the Proposed Development Site.

12.2.33. The locations of these receptors are illustrated in Figure 12-1, Volume III of this

PEI Report.


12.2.34. The assessment employs the ‘Rochdale Envelope’ approach (as detailed in the

Planning Inspectorate Advice Note 9). Given the locations of the CCGT plant, the

hybrid cooling water system and the peaking plant, which together constitute the

main noise sources, are relatively fixed in the DCO Application, any movement of

plant items within these areas is unlikely to result in significant changes to the

resultant noise levels at the surrounding receptors. Hence, having based the

modelling on the indicative site layout presented on Figures 4-2 and 4-3 in

Volume III of this PEI Report is considered to be robust.

12.2.35. To take account of the required flexibility in building heights, the maximum

proposed building heights are employed in the modelling and assessment work.

This will provide a worst case in terms of building breakout noise.

12.2.36. The assessment has also assumed the worst case mix of plant, which constitutes

both the CCGT plant and peaking plant.

12.2.37. The operational noise predictions have been carried out for the CCGT plant for

both the single-shaft and multi-shaft configurations, due to the different position

of equipment and therefore potential to cause slightly different noise contributions

to selected receptors.


Measured Noise Levels

12.3.1. A baseline noise survey was conducted between September and October 2013

in accordance with the methodology agreed with SGC and BCC in May 2013.

12.3.2. Long-term monitoring was undertaken at two locations, representative of the

nearest accessible residential receptors in each direction from the Proposed

Development Site. These were:

• LT1: Barnacre, Severn Road, Hallen; and

• LT2: Orchard Cottage, Vimpennys Lane, Easter Compton.


May 2014 Page 12-12

12.3.3. Short-term, attended noise monitoring during the day and night was undertaken

at three locations. These were:

• ST1: Marsh Common Road, Pilning;

• ST2: Severnwood Gardens, Severn Beach; and

• ST3: Severn Road, close to the existing Seabank 1 & 2 Power Station.

12.3.4. These noise monitoring locations are illustrated in Figure 12-1 (Volume III of this

PEI Report).

12.3.5. All measurements conformed to the requirements of BS 7445: 2003 (Ref. 12-7)

with regards to the positioning of the meters. During the long-term

measurements, weather conditions were generally within the weather condition

requirements. Noise data collected when weather conditions were outside the

requirements have been omitted.

12.3.6. Noise measurement data during periods when weather conditions satisfied the

requirements of BS 7445 are presented in Table 12-7.

Table 12-7: Free-field Ambient Noise Levels during Good Weather Conditions

Location Measurement address

Day Night

LAeq,T

dB*

Ave LA90,T

dB†

LAmax,fast

dB

LAeq,T

dB*

Ave LA90,T

dB†

LAmax,fast

dB

LT1 Barnacre, Hallen 49 45 80 43 38 85

LT2 Orchard Cottage, Easter Compton

50 45 84 45 38 71

ST1 Marsh Common Road, Pilning

57 53 74 45@

38@

71@

ST2 Severnwood Gardens, Severn Beach

64 54 87 60 47 76

ST3 Severn Road 71 64 90 66 41 83

* This is the lowest of the average daytime or night-time LAeq.

† This is the lowest of the average daytime or night-time LA90. @

Noise levels measured at this location at night were professionally judged to be incorrect (much higher

than expected) for a location of this type. Therefore, for a worst-case assessment noise levels at this

location have been assumed to be the same as those at Orchard Cottage, judged to have a quieter

prevailing noise climate than that at ST1.

12.3.7. Further information on the measured data is provided in Appendix G Part 2,

Volume II of this PEI Report. Table 12-8 provides a summary of the observations

during the monitoring.


May 2014 Page 12-13

Table 12-8: Observations during the Baseline Monitoring

Location Measurement address

Description of main noise sources

LT1 Barnacre, Hallen Road traffic on the M49, M5 and Severn Road, rusting leaves, and birdsong

LT2 Orchard Cottage, Easter Compton

Road traffic on the M49, birdsong, and rustling leaves

ST1 Marsh Common Road, Pilning

Road traffic on the M49 and Marsh Common Land, rustling leaves, and occasional overhead aircraft

ST2 Severnwood Gardens, Severn Beach

Road traffic on the A403 Severn Road

ST3 Severn Road Road traffic on Severn Road

Threshold Values

12.3.8. Based on the measured ambient noise levels, the following ABC Threshold

Values (from in BS 5228: 2009) have been derived and are used in this

assessment.

Table 12-9: Threshold Values at Selected Receptors

Location

LAeq,T dB Day LAeq,T dB Night

Daytime LAeq,T dB

Daytime Threshold

Value

Night-time LAeq,T dB

Night-time Threshold

Value

R1: Barnacre 49 65 43 50

R2: Elmington Manor Farm 49 65 43 50

R3: Orchard Cottage 50 65 45 50

R4: 104 Marsh Common Road 57 65 45 50

R5: 2 Severnwood Gardens 64 70 60 55

R6: Chittening Warth (90m from Severn Road)*

52 Not applicable to habitat sites

47 Not applicable to habitat sites

* This level has been calculated using a distance correction equation and based on the measured noise level 10m

from Severn Road.


12.4.1. The design of the Proposed Development has been carried out in conjunction

with the acoustics consultants to identify locations and building orientations that

would minimise the noise impact at nearby noise sensitive receptors.

12.4.2. Noise mitigation measures that were analysed during the preparation of the

concept layout included building cladding providing a minimum attenuation of

25dB Rw.


May 2014 Page 12-14


Construction Phase

Enabling Works and Site Construction

12.5.1. The estimated free-field construction noise levels at the identified receptors for

each activity during the enabling works and construction of the main Proposed

Development, including vehicle movements on site, are provided in Table 12-10.

Table 12-10: Predicted Free-Field Construction Noise Levels

Construction Activity

Predicted Total Construction Noise Level LAeq,1h dB

R1: Barnacre

R2: Elmington

Manor Farm

R3: Orchard Cottage

R4: 104 Marsh

Common Road

R5: 2 Severnwood

Gardens

R6: Chittening

Warth

Site clearance 42 42 41 38 42 63

Site earthworks 34 34 33 30 35 56

Bored piling (CFA) 37 37 36 34 38 46

Excavations and foundations

38 38 37 34 38 46

Slab construction 35 35 34 32 36 44

Steelwork construction

38 38 37 34 39 46

Finishing and fitting 34 34 33 31 35 43

Hardstanding 37 37 37 34 38 46

Access roads/car-parking

38 38 37 34 39 60

12.5.2. The significance of effect for each construction activity and at each residential

receptor is provided in Table 12-11. Receptor 6 (Chittening Warth) is discussed

after Table 12-11.


May 2014 Page 12-15

Table 12-11: Difference between Predicted Construction Noise Level and Threshold Value

Activity R1: Barnacre R2: Elmington Manor

Farm

R3: Orchard Cottage R4: 104 Marsh

Common Road

R5: 2 Severnwood

Gardens

Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance

DAYTIME

Site clearance -23 Negligible -23 Negligible -27 Negligible -24 Negligible -28 Negligible

Site earthworks

-32 Negligible -32 Negligible -35 Negligible -32 Negligible -35 Negligible

Bored piling (CFA)


Excavations and foundations


Slab construction




Finishing and fitting


Hardstanding -28 Negligible -28 Negligible -31 Negligible -28 Negligible -32 Negligible

Access roads/car-parking


NIGHT-TIME

Site clearance -8 Negligible -9 Negligible -9 Negligible -12 Negligible -13 Negligible

Site earthworks


Bored piling (CFA)



May 2014 Page 12-16

Activity R1: Barnacre R2: Elmington Manor

Farm

R3: Orchard Cottage R4: 104 Marsh

Common Road

R5: 2 Severnwood

Gardens

Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance Change

(dB)

Significance

Excavations and

foundations


Slab construction




Finishing and fitting


Hardstanding -13 Negligible -13 Negligible -13 Negligible -16 Negligible -17 Negligible

Access roads/car-

parking



May 2014 Page 12-17

12.5.3. The predicted noise levels from enabling works and construction activities fall

well below the daytime and night-time ABC threshold values for each selected

receptor R1-5. The predicted significance of this effect is therefore considered to

be negligible.

12.5.4. With the exception of site clearance and access road construction works during

both the daytime and night-time, the predicted noise levels from enabling works

and construction activities also fall below the measured LAeq levels at the nearest

habitat receptor, which is Chittening Warth within the Severn Estuary

SAC/SPA/Ramsar /SSSI sites (Receptor 6). The significance of this predicted

effect is therefore assessed as negligible.

12.5.5. During site clearance works the noise levels at R6 are predicted to be 63dB and

during access road construction noise levels are predicted to be 60dB, which

may result in a major adverse noise effect without additional mitigation; however,

the predicted noise levels are based on worst-case assumptions and do not

include control measures to reduce noise effects, which are discussed below.

12.5.6. Following the implementation of mitigation measures, such as plant selection, the

installation of temporary noise barriers around the perimeter of the Proposed

Development Site to reduce noise levels by up to 10dB (assuming the proposed

Severnside Energy Recovery Centre is not built by then and does not deliver this

level of screening), and by scheduling works, where practicable and deemed

necessary following a review of the detailed design, to minimise total noise

emissions, construction noise levels can be reduced to bring the significance of

effect of this activity at the Severn Estuary to minor adverse or negligible.

Further mitigation measures and Best Practicable Means are discussed later in

this section.

12.5.7. Noise will also be emitted during the construction of the associated infrastructure,

which comprises the proposed cooling water pipeline and electrical connection.

12.5.8. The noise emissions from the installation of the electrical connection will occur

within the existing Seabank 1 & 2 site and should therefore to a degree be

masked by the existing background noise and screened by these existing

buildings. Any HDD activities on the Proposed Development Site (if the electrical

cable is routed beneath Seabank 1 & 2) have been included as part of the onsite

works assessed above and determined to be negligible significance.

12.5.9. The estimated free-field construction noise levels at various distances from the

cooling water pipeline are provided in Table 12-12.


May 2014 Page 12-18

Table 12-12: Predicted Free-Field Daytime Construction Noise Levels associated with the Cooling Water Pipeline Construction

Construction activity

Predicted total daytime construction noise level LAeq,1h dB at various distances (metres)

10m 25m 50m 75m 100m 125m 150m 175m 200m 250m 300m

Earthworks 74 70 65 63 60 58 56 54 53 44 42

Excavation of pipeline

77 73 68 65 62 60 58 57 56 46 45

Pipeline Installation

77 70 64 60 57 55 54 53 51 42 41

Backfilling of pipeline

76 72 67 65 62 60 58 56 55 46 44

350m 400m 450m 500m 600m 700m 800m 900m 1km 1.2km 1.4km

Earthworks 41 39 38 44 42 41 40 38 37 36 34

Excavation of pipeline

43 42 41 47 45 43 42 41 40 38 37

Pipeline Installation

39 38 37 43 42 40 39 38 37 35 34

Backfilling of pipeline

43 41 40 46 44 43 41 40 39 38 36

12.5.10. The closest residential receptors to the proposed cooling water pipeline corridor

are located approximately 800m from the southernmost point of the corridor.

Estimated noise levels at this receptor (and all others) fall well below the BS 5228

minimum daytime Threshold Value of 65dB LAeq,1h and night-time Threshold Value

of 45dB LAeq,1h. At Elmington Manor Farm (1.1km from any pipeline construction

works), the estimated cooling water pipeline construction noise levels fall well

below the 65dB LAeq,1h daytime threshold and the 50 dB LAeq,1h night-time

threshold.

12.5.11. The significance of effect for construction noise during the cooling water pipeline

construction upon the closest residential receptors is therefore assessed as

negligible.

12.5.12. At Chittening Warth / Severn Estuary, which is located 200m from the closest part

of the cooling water pipeline construction works, predicted levels will be

approximately 56dB LAeq,1h. This is slightly higher than the existing ambient noise

levels experienced, therefore the magnitude of change is assessed as minor

adverse.


12.5.13. The closest residential receptors to the Proposed Development Site are located

approximately 1.1km away. BS 5228 Part 2 provides historical measured

vibration data for different types of piling and indicates that at 30m from driven


May 2014 Page 12-19

piling a vibration level of 0.88mm/s ppv is likely. A level of 0.88mm/s ppv at 30m

gives a vibration level of less than 0.1mm/s ppv at the nearest residential

receptor to the Proposed Development Site, indicating that vibration from piling

activities will not be perceptible.

12.5.14. Vibration from piling is therefore unlikely to result in a significant effect at

residential properties, particularly if other methods of piling that produce lower

levels of vibration, such as CFA (bored) piling, are used. The significance of this

potential effect is therefore considered to be negligible.

Construction Traffic

12.5.15. Road traffic estimates have been developed for the expected peak year of

construction, which is 2019 based on the current project programme.

12.5.16. Predictions have been made using the methodology given in CRTN whereby, in

the absence of residential or habitat receptors immediately adjacent to these

road links, changes in noise levels from increases in road traffic have been

predicted at a distance of 10m from each road link.

12.5.17. Road traffic noise levels have been predicted for two scenarios; the 2019

baseline (with no construction traffic) and 2019 including the peak month of

construction traffic. The predicted noise levels and calculated increase at the

closest receptors are presented in Table 12-13 below, with the significance of

effect taken from Table 12-5.

Table 12-13: Predicted Noise Increases due to Construction Traffic

Link Details 2019 Predicted LA10,18h dB Increase in Noise Level dB

Significance of Effect Baseline With

Construction

1 A403 - between Kings Road Avenue and Unclassified Road

71.5 71.6 0.1 Negligible

2 A403 - between B4055 and M48


3 A403 - between 'unclassified road' and B4064


4 M48 - between Junction 1 and the M4 (Junction 21)


5 M5 - between Junction 15/20 (M5/M4) and Junction 14 M5


6 A4 - between A4162 and A4176


7 M4 - between Junction 20/15 M4/M5 and Junction 19 M4/M32



May 2014 Page 12-20

Link Details 2019 Predicted LA10,18h dB Increase in Noise Level dB

Significance of Effect Baseline With

Construction

8 A403 – junction A403 Severn Road/ Severn Road and Chittening Road


9 A403 – outside existing Seabank access


12.5.18. The increase in road traffic noise levels as a result of increased traffic during

construction will result in an imperceptible magnitude of change. The predicted

effect of traffic noise is anticipated to be negligible. This is despite having based

the assessment on the peak month of construction traffic; the effect during other

months is predicted to be less.

Operational Noise Levels

CCGT and Peaking Plant Noise

12.5.19. The predicted worst-case free-field operational noise levels at the locations of the

receptor facades, for both the single and multi-shaft options are presented in

Table 12-14.

12.5.20. All predictions include the operation of the peaking plant units, and assume their

operation for 100% of the assessment period; in practice they are likely to

operate for only a fraction of the year and therefore this is an overestimate. The

current best estimate is that the CCGT units would operate on average 31% over

the station lifetime and the peaking plant will be capped at a maximum 1,500

hours per year operation. Since the peaking plant can comprise either OCGT or

reciprocating engines, two scenarios have been modelled: 2 x 120MW gas

turbines or 13 x 18MW reciprocating engines, both representing up to 240MW of

peaking plant units.

12.5.21. It has been assumed that during the detailed design of the Proposed

Development residual potential noise impacts will be further mitigated by design,

for example through the additional enclosure of the engines within buildings. For

this assessment it has therefore been assumed that the internal reverberant

noise levels within the peaking plant units will be comparable for both the gas

turbine and the reciprocating engine options.


May 2014 Page 12-21

Table 12-14: Predicted Operational Noise Levels

Receptor Predicted Operational Noise Level LAeq,1h dB

Option 1 – Single Shaft Option 2 – Multi Shaft

Daytime

R1: Barnacre 28 27

R2: Elmington Manor Farm 34 31

R3: Orchard Cottage 33 30

R4: 104 Marsh Common Road 32 29

R5: 2 Severnwood Gardens 35 37

R6: Chittening Warth* 40 42

Night-time

R1: Barnacre 29 29

R2: Elmington Manor Farm 35 31

R3: Orchard Cottage 34 31

R4: 104 Marsh Common Road 32 30

R5: 2 Severnwood Gardens 36 37

R6: Chittening Warth* 40 42

* Noise levels at Chittening Warth are predicted to be higher from the operation of the multi-shaft option due to the

location of the air inlet filters.

12.5.22. Employing the assessment methodology given in BS 4142, the likelihood of

complaint at each residential receptor has been assessed, based on the

calculated Rating Level (which includes a +5dB penalty for a worst-case

assessment) and measured background noise level at the receptor.

12.5.23. The BS 4142 assessment for the receptors R1 to R5 is presented in Table 12-15

for the single-shaft option and in Table 12-16 for the multi-shaft option. Receptor

R6 results are presented in Table 12-17.

Table 12-15: BS 4142 Assessment with 5dB Penalty – Single Shaft Configuration

Receptor Measured LA90 dB

Predicted LAeq dB

Rating Level LAr,T

dB

Difference between Rating Level and LA90 dB

BS 4142 Assessment Significance

Daytime

R1: Barnacre

45 28 33 -12 Complaints unlikely Negligible

R2: Elmington Manor Farm

45 34 39 -6 Less than marginal significance

Negligible

R3: Orchard Cottage


Negligible

R4: 104 51 32 37 -14 Complaints unlikely Negligible


May 2014 Page 12-22


Predicted LAeq dB

Rating Level LAr,T

dB


BS 4142 Assessment Significance

Marsh Common Road

R5: 2 Severnwood Gardens


Night-time

R1: Barnacre


Negligible


38 35 40 +2 Marginal Significance Minor adverse

R3: Orchard Cottage

38 34 39 +1 Marginal Significance Minor adverse

R4: 104 Marsh Common Road


Negligible



Negligible

Table 12-16: BS 4142 Assessment with 5dB Penalty – Multi Shaft Configuration


Predicted LAeq dB

Rating Level LAr,T

dB


BS 4142 Assessment

Significance

Daytime

R1: Barnacre




Negligible

R3: Orchard Cottage







May 2014 Page 12-23


Predicted LAeq dB

Rating Level LAr,T

dB


BS 4142 Assessment

Significance

Night-time

R1: Barnacre


Negligible



Negligible

R3: Orchard Cottage


Negligible



Negligible



Negligible

12.5.24. Based on the methodology given in BS4142, for the daytime period, the single-

shaft configuration is expected to result in ‘complaints unlikely to ‘less than

marginal significance’ at nearby residential receptors. At night-time, the effect

ranges from ‘less than marginal significance’ to ‘marginal significance’ prior to

mitigation.

12.5.25. Prior to additional mitigation measures (which are discussed later in this chapter),

the worst-case predicted noise levels from the operation of the single-shaft

configuration results in negligible effects during the daytime and negligible to

minor adverse effects during the night-time.

12.5.26. For the daytime period, the multi-shaft configuration is expected to result in

‘complaints unlikely’ to ‘less than marginal significance’ at nearby residential

receptors. At night-time, the effect is ‘less than marginal significance’.

12.5.27. Prior to additional mitigation measures (which are discussed later in this chapter),

the worst-case predicted noise levels from the operation of the multi-shaft

configuration results in negligible effects during both daytime and night-time

periods.

12.5.28. Analysis of the source noise contributions for each plant configuration indicates

that the dominant contributing noise sources for both configurations are the

hybrid cooling water system and the air inlet filters to the turbine halls.


May 2014 Page 12-24

12.5.29. The predicted overall operational noise levels at a location representative of

Chittening Warth / Severn Estuary (R6) are presented in Table 12-17, along with

the estimated significance of effect.

Table 12-17: Predicted Operational Noise Levels at Chittening Warth prior to Additional Mitigation

Time of Day

Existing Ambient Noise Level, LAeq dB*

Single Shaft Multi Shaft

Overall Noise Level LAeq dB

Change Significance of Effect



Daytime 52 52 0 Negligible 52 0 Negligible

Night-time 45 46 +1 Negligible/minor adverse

47 +2 Minor adverse

* This level has been calculated using a distance correction calculation and assuming the dominant baseline noise source is from road traffic on Severn Road.

12.5.30. The significance of predicted changes in daytime noise levels is assessed as

negligible for both the single-shaft and multi-shaft options.

12.5.31. The significance of predicted changes in night-time noise levels is assessed as

negligible/minor adverse for the single-shaft option and minor adverse for the

multi-shaft option prior to additional mitigation.

12.5.32. The operation of the Proposed Development may also require the use of

emergency sirens. These will sound during times of emergency and during

routine testing. It is understood that some existing surrounding industrial sites are

COMAH sites which also have operational sirens which are tested regularly. As a

result of their expected short term use, in emergency situations only, the noise

effects due to the operation of sirens at the Proposed Development Site are

unlikely to be significant and are assessed as negligible.

Operation of the Associated Infrastructure

12.5.33. The operation of the cooling water pipeline, electricity cables and associated

pump house and substation is not anticipated to emit high levels of noise from

the Other DCO Land. In addition, there are no residential receptors within close

proximity. Therefore, an operational noise assessment has not been undertaken

for the associated infrastructure and the effects are assessed as negligible.

Operational Traffic

12.5.34. The operation of the development is not predicted to produce significant amounts

of additional traffic. There will be up to 40 workers onsite during operation

(spread over three 8 hour shifts), plus the occasional deliveries. This is

considerably less traffic than the construction stage, which was assessed as


May 2014 Page 12-25

negligible, and hence, an operational road traffic noise assessment has therefore

been scoped out and is assumed to be of negligible significance.

Mitigation Measures

Construction Noise Mitigation

12.5.35. With regards to residential receptors, as predicted construction noise levels will

easily comply with the daytime and night-time Threshold Levels as given in

BS 5228, no mitigation is required. However, the contractor will follow Best

Practicable Means to further reduce the noise effect upon the local community.

This will include the following:

• All construction plant and equipment will comply with EU noise emission

limits;

• Proper use of plant with respect to minimising noise emissions and

regular maintenance. All vehicles and mechanical plant used will be fitted

with exhaust silencers and shall be maintained in good efficient working

order;

• Selection of good plant, where appropriate (in other words, taking into

account noise emissions when selecting plant). Compressors will be

‘sound reduced’ models fitted with properly lined and sealed acoustic

covers which should be kept closed whenever the machines are in use

and all ancillary pneumatic percussive tools will be fitted with mufflers or

silencers of the type recommended by the manufacturers;

• Machines in intermittent use will be shut down in the intervening periods

between work or throttled down to a minimum;

• Where possible, ancillary plant such as generators, compressors and

pumps will be positioned so as to cause minimum noise disturbance, i.e.

furthest from receptors or behind close boarded noise barriers. If

necessary, acoustic enclosures will be provided and/or acoustic

shielding; and

• Construction contractors will be obliged to adhere to the codes of

practice for construction working and piling given in BS 5228 and the

guidance given therein minimising noise emissions from the Proposed

Development Site.

12.5.36. Consideration will be given to monitoring and acting upon noise complaints in the

CEMP during the construction phase.


May 2014 Page 12-26

Operational Noise Mitigation

12.5.37. The primary mitigation for noise from fossil fuel generating stations is through

good design. This includes enclosure of plant and machinery in noise reducing

buildings wherever possible to minimise the potential for operations to create

noise. Noise from gas turbines will be mitigated by attenuation of inlets and

exhausts to reduce any risk of low frequency noise transmission.

12.5.38. The assessment has taken a worst-case approach, with the employment of a +5

dB(A) correction to account for possible tonal components to the emitted noise

from the plant.

12.5.39. At the detailed design stage, post-consent, the plant will be designed such that

any significant tonal components are eliminated through, for example, the use of

silencers, enclosures and appropriate specification building cladding. As

mitigation measures should remove the tonal component the +5dB penalty does

not need to be applied.

12.5.40. Tables 12-18 and 12-19 present the findings of a BS 4142 assessment following

the implementation of these mitigation measures.

Table 12-18: BS 4142 Assessment with Mitigation – Single Shaft


Predicted LAeq dB

Rating Level LAr,T dB


BS 4142 Assessment

Significance

Daytime

R1: Barnacre

45 28 28 -17 Complaints unlikely

Negligible



Negligible

R3: Orchard Cottage


Negligible



Negligible



Negligible

Night-time

R1: Barnacre


Negligible


May 2014 Page 12-27


Predicted LAeq dB



BS 4142 Assessment

Significance



Negligible

R3: Orchard Cottage


Negligible



Negligible



Negligible

Table 12-19: BS 4142 Assessment with Mitigation – Multi Shaft


Predicted LAeq dB



BS 4142 Assessment

Significance

Daytime

R1: Barnacre


Negligible



Negligible

R3: Orchard Cottage


Negligible



Negligible



Negligible

Night-time

R1: Barnacre


Negligible



Negligible

R3: Orchard 38 31 31 -7 Less than marginal

Negligible


May 2014 Page 12-28


Predicted LAeq dB



BS 4142 Assessment

Significance

Cottage significance



Negligible



Negligible

12.5.41. Based on the methodology given in BS4142, for the daytime period, the single-

shaft configuration is expected to result in ‘complaints unlikely’ at nearby

residential receptors. At night-time, the effect ranges from ‘complaints unlikely’ to

‘less than marginal significance’.

12.5.42. The predicted noise levels from the operation of the single-shaft configuration

results in negligible effects during both the daytime and night-time periods.

12.5.43. For the daytime period, the multi-shaft configuration is expected to result in

‘complaints unlikely’ at nearby residential receptors. At night-time, the effect

ranges from ‘complaints unlikely’ to ‘less than marginal significance’.

12.5.44. The predicted noise levels from the operation of the multi-shaft configuration

results in negligible effects during the daytime and night-time periods.

12.5.45. The predicted Rating Levels for both the single-shaft and multi-shaft options meet

SGC’s criterion of equal to, or below, background noise levels at all receptors.

12.5.46. Analysis of the source noise contributions for each plant configuration indicates

that the dominant contributing noise sources for both configurations are still the

hybrid cooling water system and the air inlet filters to the turbine halls.

12.5.47. As the dominant contributing noise sources at the surrounding residential

receptors are the hybrid cooling water system and air inlet filters, the irregular

operation of the peaking plant is unlikely to attract the attention of residents at

these properties. It is noted that, whilst the peaking plant may operate at any

time, it is highly likely that it will only be in operation during the most demanding

parts of the daytime period, when predicted Rating Levels are a minimum of 6 dB

below the prevailing background noise levels.

12.5.48. The assessment of noise impacts upon Chittening Warth is based on the change

in the noise level at the receptor as the assessment methodology given in

BS4142 is not appropriate. Therefore the assessment of noise impacts with


May 2014 Page 12-29

mitigation measures will be the same as the assessment without mitigation.

However, an assessment of noise impacts at Chittening Warth with mitigation has

been included for completeness.

12.5.49. The predicted overall operational noise levels at a location representative of

Chittening Warth / Severn Estuary (R6) are presented in Table 12-20, along with

the estimated significance of effect.

Table 12-20: Predicted Operational Noise Levels at Chittening Warth – With Mitigation

Time of Day

Existing Ambient Noise Level, LAeq dB*

Single Shaft Multi Shaft





Daytime 52 52 0 Negligible 52 0 Negligible

Night-time 45 46 +1 Negligible/minor adverse

47 +2 Minor adverse

* This level has been calculated using a distance correction calculation and assuming the dominant

baseline noise source is from road traffic on Severn Road.

12.5.50. The significance of predicted changes in daytime noise levels is assessed as

negligible for both the single-shaft and multi-shaft options.

12.5.51. The significance of predicted changes in night-time noise levels is assessed as

negligible/minor adverse for the single-shaft option and minor adverse for the

multi-shaft option.

12.5.52. Acoustic modelling and assessment will form an integral part of the detailed

design process. As the design progresses, efforts will be made to reduce noise

levels further, where practicable, to provide negligible effects at all receptors.

12.5.53. A procedure shall be put in place once the Proposed Development is operational

to receive and act on any noise complaints.

12.6. Decommissioning Phase

12.6.1. It is envisaged that the Proposed Development will have a design life of 30 years

and a possible operating life beyond this depending on the number of running

hours.

12.6.2. It is anticipated that the decommissioning phase would generate comparable

noise to the construction works, and would decommission the cooling water

pipeline in-situ, avoiding the need for extensive excavation works. The effect of

the decommissioning phase is therefore expected to be similar in nature to the

construction activities, albeit of a shorter duration.


May 2014 Page 12-30

12.6.3. Decommissioning is therefore expected to generally lead to a negligible effect

on residential and habitat receptors.


12.7.1. A summary of the residual effects, assuming implementation of the proposed

mitigation, is presented in Table 12-21 below.


Description Nature of effect BS4142 Rating Significance of Effect

Construction Noise from Standard Activities – Residential Receptors

Temporary N/A Negligible

Construction Noise from Standard Activities – Ecological Receptors

Temporary N/A Minor

Construction Traffic Temporary N/A Negligible


Temporary N/A Negligible

Operational Noise (single or multi shaft)

Permanent

‘complaints unlikely’ to ‘less than marginal significance’

Negligible

Decommissioning Temporary N/A Negligible

12.7.2. This chapter has provided an assessment of the noise and vibration impacts

likely to arise as a result of the construction and operation of the Proposed

Development.

12.7.3. Noise levels were predicted at the facades of the closest residential receptors to

the Proposed Development Site, and at a location representative of Chittening

Warth / Severn Estuary to consider the nearest habitat receptors.

12.7.4. The predicted construction noise levels were assessed against the daytime and

night-time Threshold Values derived from the BS 5228 ABC method for

assessing the noise effects from construction activities. Predictions have shown

that noise levels from standard construction activities will fall below the Threshold

Values at the selected residential receptors during all construction activities

during both daytime and night-time periods. A negligible significance of effect

has therefore been predicted.

12.7.5. The contractor will employ Best Practicable Means in order to ensure that

construction noise is kept to a minimum.


May 2014 Page 12-31

12.7.6. Noise levels from construction traffic during the construction phase are not

expected to result in a perceptible noise effect. A negligible adverse significance

of effect has therefore been predicted for road traffic.

12.7.7. The operational noise effects were predicted using the noise modelling software

package SoundPLAN. This software package allows the creation of a 3D model

of the Proposed Development Site and surrounding area to allow the propagation

of noise to be predicted.

12.7.8. The predicted noise levels were assessed against the average background noise

level recorded during good weather.

12.7.9. With the implementation of mitigation measures, an overall significance of effect

of negligible is predicted for both the single-shaft and multi-shaft options.


12.8.1. In order to understand the potential effects of the Proposed Development on the

noise climate it is important to consider potential cumulative effects. Cumulative

effects may be caused by an interaction of different effects to constitute a larger,

more significant effect, such as increased noise and vibration at the closest noise

sensitive properties due to other future developments.

12.8.2. Several developments were identified as potentially causing cumulative effects

and these are listed in Chapter 7: Assessment Methodology. The future

cumulative baseline would include extensive existing and proposed industrial

developments located to the west of the M49.

12.8.3. With regards to cumulative construction noise impacts upon residential receptors,

predicted noise levels from the construction of the Proposed Development fall

well below the ABC Threshold Values given in BS5228. As the predicted

construction levels are so low, construction noise from the Proposed

Development will make a negligible contribution to any cumulative construction

noise levels associated with any other schemes.

With mitigation in place to control tonal noise emissions from the operational

Proposed Development, the worst-case Rating Level is 3dB below the measured

background level. For the Severnside Energy Recovery Centre and the Viridor

Avonmouth Energy from Waste (EfW) facility, predicted Rating Levels were

significantly below the measured background noise level, therefore the

cumulative noise impact upon residential receptors is likely to be no greater than

the noise impacts given in this chapter. Assuming that the Avon Power Station

scheme is designed to control noise to the same degree as the Proposed

Development the cumulative worst-case Rating Level will be 0dB above the

measured background level. This is assessed as of ‘less than marginal


May 2014 Page 12-32

significance’ in BS 4142, which results in a cumulative significance of effect of

negligible.




Any changes that lead to differing or new impacts and effects will be assessed



preparation of this PEI Report and the final ES; noise conditions are dynamic and

evolve over time. The Proposed Development Site is currently subject to

excavation, top soil stripping, and levelling in certain areas in order for third












12.10. References

Ref. 12-1 BS 5228: 2009+A1: 2014 ‘Code of Practice for Noise and Vibration

on Construction and Open Sites, Part 1: Noise’. British Standards

Institute.

Ref. 12-2 BS 4142: 1997, ‘Method for rating industrial noise affecting mixed

residential and industrial areas’.

Ref. 12-3 ‘Guidelines for Community Noise’, World Health Organisation, 1999.

Ref. 12-4: ISO 9613-2: 1996 ‘Attenuation of sound during propagation outdoors’.

Ref. 12-5 Highways Agency et al. (2008). Design Manual for Roads and

Bridges Volume 11 Section 3 Part 7 ‘Noise and Vibration’.

Ref. 12-6 CRTN Department of Transport and the Welsh Office (1988).

Calculation of Road Traffic Noise.


May 2014 Page 12-33

Ref. 12-7 British Standard BS 7445: 2003 ‘Description and Measurement of

Environmental Noise’, British Standards Institute, 2003.

Seabank 3 PEI Report – Chapter 13 Ground Conditions

May 2014 Page 13-1

13. Ground Conditions

13.1. Introduction

13.1.1. This chapter of the PEI Report presents an assessment of the potential effects

of the Proposed Development and associated infrastructure on land quality and

groundwater resources.

13.1.2. It identifies key land contamination receptors and their sensitivities, including

the principal water resources, and addresses the direct and indirect effects of

the Proposed Development and associated infrastructure on these receptors.

The assessment of the predicted magnitude of the effects is made in the

context of the existing site conditions (baseline conditions), predicted

conditions during site preparation and construction works, the conditions

expected once the Proposed Development and associated infrastructure is

operational and during eventual future decommissioning. The need for

mitigation measures is addressed where applicable, and residual effects

following their implementation have been identified.

13.1.3. The previous land use history and sensitive receptors within the vicinity of the

Proposed Development Site have been identified. This chapter includes a

Conceptual Site Model (CSM), which establishes relevant source – pathway –

receptor pollutant linkages for the potential land contamination issues

identified.

Consultation

13.1.4. Table 13-1 provides an overview of responses from key consultees during the

Scoping phase.



BCC

Recommends remedial investigation along the route of the proposed cooling water pipeline as the study corridor passes through land known to have been subject to contaminating land uses and sensitive receptors (rhines: man-made surface water drainage ditches).

Ground investigation of cooling water pipeline route is discussed in see section 13.4.

EA

The EIA should consider the construction phase and post-construction phase risks to controlled waters, i.e. dewatering and or the construction of deep excavations.

Both construction and post-construction phase risks to controlled waters have been considered in throughout this chapter.


May 2014 Page 13-2


The effect of the development on any private water supplies in the area must be considered.

There is no licenced groundwater abstractions registered within the vicinity of the Proposed Development Site or associated infrastructure. This is discussed within the chapter.

Any controlled water risk assessments completed within the EIA should be based on Environmental Quality Standards (EQS) appropriate for the site context, i.e. adjacent to the Severn Estuary SPA. EQS for the assessment of rhines and ditches on site should be the same as those for the SPA.

No controlled water risk assessments have been carried out for this PEI Report as, at the time of writing, the results of the ground investigation, including chemical analyses, were not available. This data and the need for a controlled water risk assessment will be presented in the final ES.

13.1.5. Additional informal consultation has been carried out since receipt of the

Scoping Opinion from the Planning Inspectorate in February 2013, with

Environmental Health Officers of BCC and SGC, and the EA, in respect of

baseline land quality conditions and the proposed ground investigation

specification. SGC and BCC confirmed they did not have any comments on the

scope of work, although BCC noted “The proposed route will have potential

contamination issues as it passes through and by historical areas of landfilling,

industrial activity etc”. This comment related to the electrical connection

corridor presented at Scoping however, which has been modified to avoid the

historical area of landfilling.

13.1.6. The EA responded on the 5 December 2013 with the following comments;

• The developer should ensure that the ground investigation carried out is

adequate to inform contaminated land issues as well as geotechnical

ones,

• To inform the risk assessment for controlled waters [we would

recommend that] the soil samples are analysed for leachable

contaminants. Where possible it is recommended that the groundwater

be sampled.

13.1.7. The approach taken to the ground investigation and risk assessment of the

Proposed Development Site is outlined in section 13.2 of this chapter.

However, in summary, following the review of Phase 1 desktop information, it

was determined that the majority of the Proposed Development Site comprises

previously undeveloped land, with the exception of the former railway and farm

buildings, and as such the location of the exploratory holes was driven by

geotechnical requirements.


May 2014 Page 13-3

13.1.8. With reference to the EA comment regarding leachate testing, this was not

undertaken on soil samples collected during the ground investigation of the

Proposed Development Site, as groundwater was found to be readily available

within each of the installed boreholes and the results of direct groundwater

sampling are considered to be of more use than leachate results when

considering the risk to controlled waters.

13.2. Legislation and Planning Policy Context

13.2.1. Potential redevelopment on areas of brownfield land must take into account the

regulatory context of the work, provide information that it is fit for purpose, and

be in accordance with good practice and relevant guidance. An environmental

assessment of the condition of the DCO Site must not only consider the

potential receptors of human health and controlled waters, but also include a

review of the relevant legislation and planning policy that applies to the DCO

Site and its immediate environs.

13.2.2. Chapter 8: Planning Policy Context sets out the overarching policy framework

relevant to the Proposed Development. The final ES will include a detailed

description of the policies relevant specifically to the ground conditions

assessment. For the Purposes of this report these are summarised in Appendix

D, Volume II of this PEI Report.



13.3.1. A variety of data sources have been consulted, such as published maps,

commercially available environmental database records, including an

Envirocheck Report obtained from Landmark Information Group (Ref. 13- 1)

and available third party technical reports. Each data source is referenced as

appropriate in the following sections of this chapter.

13.3.2. URS has undertaken ground investigation (GI) works within the Proposed

Development Site. No GI has been undertaken within the CCR Site or the

Other DCO Land, which will include the proposed electrical connection and

proposed water pipeline corridor. The CCR Site will be reinstated to grassland

following construction, and the electrical connection and cooling water pipeline

are not sensitive to, and therefore should not be affected by, contamination

(although localised remediation or removal of soils may be required).

13.3.3. The GI was designed by URS on behalf of the Applicant and the location of the

exploratory holes was determined by the layout of the Proposed Development


May 2014 Page 13-4

at the time of planning the survey (in July 2013) and also to target the railway

track area in the north of the Proposed Development Site. The GI comprised:

• The excavation of 7 boreholes using shell and auger with rotary follow

on techniques to a maximum depth of 26.15m bgl;

• The excavation of 12 Trial Pits using a JCB 3CX excavator, with

California Bearing Ratio (CBR) testing carried out in each;

• Twenty one Cone Penetrometer Tests (CPT) including dissipation tests

were carried out using a truck mounted CPT rig;

• In-situ geotechnical testing in all boreholes;

• Collection of soil samples for geotechnical laboratory analysis;

• Soil, groundwater and surface sampling and analysis, and;

• Ground gas monitoring.

13.3.4. The Phase II Geotechnical and Contamination Assessment report on the GI is

included in Appendix I Part 4, Volume II of this PEI Report and information

obtained from the GI has been included in the appropriate baseline sections

below.

13.3.5. A site visit along the cooling water pipeline was undertaken by URS on 18

November 2013. Information from that site visit is included as appropriate

below.

13.3.6. The EA / Defra’s Contaminated Land Report 11 (CLR11) ‘Model Procedures for

the Management of Land Contamination’ (Ref. 13-2) provides for staged and

risk-based data interpretation. This commences with a Preliminary Risk

Assessment (PRA, also known as Stage 1 risk assessment), which is normally

a desk based assessment to develop an initial Conceptual Site Model (CSM) to

identify any source-pathway-receptor Pollutant Linkages that might apply at the

Site and would be used to define any potential risks. Where potential risks are

identified, the CSM would be used to design an intrusive site investigation to

acquire additional data on the pollutant linkages identified.

13.3.7. Where site investigation data confirms the presence of contaminants of

concern, the laboratory analytical data are screened against Generic

Assessment Criteria (GAC), defined through the process of a Stage 2 Generic

Quantitative Risk Assessment (GQRA). GAC are conservative in nature and

are used to screen out risks that are unlikely to represent an “unacceptable

risk” to the receptors defined in the CSM – the GAC are set to ensure that, if


May 2014 Page 13-5

they are not exceeded, it is extremely unlikely that relevant receptors will be

exposed to significant levels of risk.

13.3.8. In cases where Stage 2 GQRA GAC are exceeded, it is normally appropriate to

proceed to Stage 3 Detailed Quantitative Risk Assessment (DQRA) to define

Site Specific Assessment Criteria (SSAC). Stage 3 DQRA will often require that

additional site investigation is undertaken to collect specific additional data to

refine the risk assessment process and determine the need for further action,

such as land and / or groundwater remediation.


13.3.9. A review of baseline conditions at the DCO Site was undertaken to evaluate

the nature of potential effects associated with the Proposed Development and

associated infrastructure. The magnitude of potential changes (using worst

case scenarios) during the operational, construction and decommissioning

phases of the development have been qualitatively described and categorised,

as set out in Table 13-2. The magnitude of potential changes is assessed

against baseline conditions, prior to the consideration of mitigation measures

and includes consideration of the sensitivity of the receptor.

Table 13-2: Criteria to Determine Magnitude of Change

Magnitude of Change

Criteria Example / Description

High

Results in loss of an attribute and is likely to cause exceedances of statutory objectives and/or breaches of legislation

Contamination of a potable source of abstraction

Medium

Results in a change to the integrity of attribute or the loss of part of attribute, possibly with/ without exceedances of Statutory objectives or with/ without breaches of legislation.

Reduction in the value of the feature

Low

Results in a small change to an attribute that does not result in a change to its integrity or the loss of part of the attribute.

Measurable changes in attribute, but of limited size and/or proportion

Neutral Results in no discernible change or a change on attribute of insufficient magnitude to affect the use / integrity

Discharges to watercourse but no significant loss in quality of the feature

13.3.10. The significance of residual effects is assessed in accordance with criteria in

Table 13-3 and reflects the effect after incorporation of mitigation methods to

be applied in the implementation of the Proposed Development and associated

infrastructure.


May 2014 Page 13-6

13.3.11. The criteria for classifying significance of effects are summarised in Table 13-3.

Moderate and major effects are considered ‘significant’ for the purpose of this

assessment.

Table 13-3: Description of Significance of Effects

Significance Description

Major Adverse

Considerable detrimental effect (by extent, duration or magnitude) of more than local significance or in breach of recognised acceptability / legislation / policy standards, which is clearly significant.

Moderate Adverse Limited detrimental effect (by extent, duration or magnitude) that may be considered significant.

Minor Adverse Slight, very short or highly localised detrimental effect.

Negligible No appreciable effect on the attribute, or the attribute of negligible importance

Minor Beneficial Slight, very short or highly localised beneficial effect.

Moderate Beneficial Limited beneficial effect (by extent, duration or magnitude) that may be considered significant.

Major Beneficial Considerable beneficial effect (by extent, duration or magnitude) of more than local significance which is clearly significant.

13.3.12. Significance is also considered in terms of timescale (short, medium or long

term), permanence (reversible or permanent) and the geographic scale of the

effect (local, district, regional, national or international). For example, a short

duration release of suspended solids to controlled waters could result in the

temporary closure of a potable water abstraction (high magnitude), but the

effects would be expected to be short-term and fully reversible (minor adverse

significance).

13.3.13. These definitions take into account the large body of technical guidance that

has been produced in the UK for the assessment of ground conditions and

water resources by the Government (Defra and its predecessor departments),

and agencies such as the EA.


13.3.14. The Rochdale Envelope parameters outlined in Chapter 4: Project Description

do not significantly affect the input parameters utilised in either the operational

or construction ground conditions assessments, and consequentially the

outcome of these assessments will not vary. Therefore the assessment adopts

conservative (worst case) values where assumptions are necessary.


May 2014 Page 13-7


13.4.1. To assist the description of baseline conditions at the DCO Site, this section

first describes conditions within and surrounding the Proposed Development

Site and the electrical connection corridor within Seabank 1 & 2. It then

discusses the baseline conditions within the remainder of the DCO Site that will

contain the cooling water pipeline.

Proposed Development Site and Electrical Connection Corridor

13.4.2. The Proposed Development Site, as illustrated in Figure 3-2 (Volume III of this

PEI Report), is generally flat lying, undeveloped open grassland which is

drained by a network of rhines (drainage channels) and ditches that flow into

the Severn Estuary to the northwest. The Red Rhine is the largest drainage

channel within the Proposed Development Site and one of the main rhines in

this area. It currently flows in a southeast to northwest direction through the

middle of the Proposed Development Site.

13.4.3. It is understood that the current route of the Red Rhine is manmade and

historically the route has varied which is likely to have resulted in relic stream

channel features within the Proposed Development Site’s superficial and

bedrock geology.

13.4.4. There are currently no buildings or infrastructure on the Proposed Development

Site with the exception of the disused railway track in the northwest corner.

13.4.5. The land adjacent to the north of the Proposed Development Site comprises

the former Terra Nitrogen and ICI site, which was most recently used as a

fertiliser manufacturing plant. This site ceased to operate in 2008, and the

majority of the buildings associated with its former use have now been

demolished and it is now predominantly a cleared and level site of

hardstanding.

13.4.6. The land to the east and northeast of the Proposed Development Site

comprises undeveloped open fields with the M49 beyond. This land is subject

to extant planning permission from 1957/58 however and is currently subject to

land raising in preparation for a large scale industrial warehouse and

distribution complex.

13.4.7. The existing Seabank 1 & 2 generating station is located immediately

southwest of the Proposed Development Site with the land extending toward

the west currently comprising an overgrown grassed area part of which is a

demolished former gas storage facility. The proposed route of the electrical

connection crosses Seabank 1 & 2 to the Seabank Substation, which is

immediately south of this existing generating station.


May 2014 Page 13-8

13.4.8. The land to the south of the Proposed Development Site, and west of Ableton

Lane, comprises a former landfill site which has been filled and raised to

approximately 2.5m above the existing ground level of the Proposed

Development Site. The land east of Ableton Lane, south of the CCR Site, is

undeveloped grassed fields known as Crooks Marsh.

13.4.9. Photographs of the Proposed Development Site and surrounding land use are

presented in Appendix I Part 2 and 3, Volume II of this PEI Report.

Site History and Development

13.4.10. Table 13-4 describes the history of the Proposed Development Site and the

part of the Other DCO Land that is proposed for the electrical connection within

Seabank 1 & 2. The table is based on published historical mapping provided

within the Envirocheck Report (Ref. 13-1).

Table 13-4: Historical Land Use within the Proposed Development Site and Other

DCO Land for Electrical Connection

Published Date

Map Scale Description

1881 1:2,500 The Proposed Development Site and electrical connection corridor comprises a series of undeveloped fields with field boundaries. An unnamed track is mapped across the centre of the Proposed Development Site from southwest to northeast. A second unnamed track runs southeast to northwest along the north western boundary, and a series of drainage ditches cross-cross the Proposed Development Site. Three unlabelled small rectangular features are shown adjacent to the west of the central track and one square feature is located at the centre of the southern Proposed Development Site.

1881 - 1965 1:2,500 Mapping does not show any significant changes in the Proposed Development Site and the electrical connection corridor.

1965 1:10,560 The Proposed Development Site remains largely unchanged until pre 1965 when a drain is developed through the centre of the site running southeast to northwest (the diversion of the Red Rhine).

A rail track has been developed in the northern section of the Proposed Development Site and continues toward the south east, extending into the CCR Site (it is labelled as dismantled by 1999 mapping).

The electrical connection corridor is largely unchanged although development has taken place immediately west which has resulted in field boundaries previously crossing the route having been removed and a new site perimeter established.

1970 1:1,250 The square feature along the southern boundary of the Proposed Development Site is labelled as Stowick Cottage. The three rectangular features are no longer present. The track running through the centre of the Proposed Development Site is labelled Ableton Lane. The remainder of the Site is largely unchanged.

1971 – 1972 1:2,500 A rectangular embankment feature is shown on the southern


May 2014 Page 13-9

Published Date

Map Scale Description

and 1972 - 1977

boundary of the Proposed Development Site in the eastern section which may be associated with the development of a drainage ditch. The feature is not shown on mapping after 1992.

1975 1: 10,000 The drain developed through the centre of the Proposed Development Site is now labelled Red Rhine.

A drain appears to have been developed in line with the proposed route of the electrical connection.

1992 1:2,500 Stowick Cottage is no longer present. The remainder of the Proposed Development Site is largely unchanged.

2006 1: 10,000 Five pylons are now present on the Proposed Development Site. The remainder of the Site is largely unchanged.

The route of the proposed electrical connection is now located within the newly developed Seabank 1 & 2 site.

13.4.11. Although not shown on OS Maps, a number of gas and water pipelines are

understood to have been installed beneath the Proposed Development Site

during the construction of Seabank 1 & 2, in approximately 2000.

13.4.12. Table 13-5 describes the development of the land surrounding the Proposed

Development Site. It also describes the area surrounding the proposed

electrical connection corridor within Seabank 1 & 2. This table is based on

published historical mapping provided within the Envirocheck Report (Ref. 13-

1).

Table 13-5: Historical Development of Land Surrounding the Proposed Development Site and

Other DCO Land for the Electrical Connection

Published Date

Map Scale

Description

1881 1:2,500 The area surrounding the Proposed Development Site and the part of the Other DCO Land that will contain the electrical connection is shown to largely comprise undeveloped fields.

Stowick Farm is located 100m to the north of the Proposed Development Site.

Land adjacent to the south of the Proposed Development Site is largely undeveloped except for an unlabelled farm approximately 150m to the south.

The Red Rhine is shown approximately 150m northeast of the Proposed Development Site running in a southeast to northwest direction. An unlabelled farm is shown 100m north of the Red Rhine.

1903 1:2,500 Crook’s Marsh Farm is labelled approximately 100m to the north of the Proposed Development Site. The remainder of the surrounding areas remain largely unchanged.

1903 – 1965

1:10,000 Mapping does not show any significant changes of the land surrounding the Proposed Development Site and electrical connection.


May 2014 Page 13-10

Published Date

Map Scale

Description

1965 (1965 – 1969)

1:10,000 The surrounding areas remain largely unchanged until the 1965 mapping which shows that extensive development has taken place.

A large industrial development, labelled Works, is present adjacent to the north of the Proposed Development Site including an associated rail track, which is both immediately adjacent and also encroaches the northern section of the Proposed Development Site.

Three small and two large circular features are present on land adjacent to the northwest of the Proposed Development Site (on land now occupied by Seabank 1 & 2), later labelled Seabank Gas Works.

The route of the Red Rhine has been straightened to pass along the north of the Seabank Gas Works.

Land adjacent to the east and south remains largely unchanged.

1970 1:1,250 The industrial site to the north comprises several large buildings, three rectangular tanks and at least six circular tanks.

Seabank Gas Works has been further developed and the works includes a series of at least ten banks of tanks and chimneys. The site adjacent to the northwest comprises at least six circular tanks, approximately 25m in diameter, which extend toward the north and west.

Land adjacent to the east and south remains largely unchanged.

1972 - 1977

1:2,500 A gas works comprising two circular tanks and a reservoir has been developed on land approximately 200m to the southeast of the Proposed Development Site.

1974 – 1975

1:10,000 The large industrial site to the north is labelled Severnside Works.

1999 1:10,000 The Seabank Gas Works on land adjacent to the west and northwest has been demolished.

Land adjacent to the south west is labelled disused landfill.

2006 1:10,000 The former Seabank Gas Works, adjacent to the west of the Proposed Development Site and immediately adjacent to the route of the electrical connection has been developed into Seabank power station (Gas fired).

The land adjacent to the north west remains undeveloped following the demolition of the large circular tanks.

Land to the use to the north, east and south remains largely unchanged except for the development of pylons which cross the Proposed Development Site but also extend to the north from the eastern section.

2013 1:10,000 The majority of the buildings of the Severnside Works adjacent to the north have been demolished.

The other surrounding areas remain unchanged.

13.4.13. The following paragraphs describe the current site condition and the

development of the surrounding areas based on a site visit undertaken during

November 2013, site mapping and also from the EA publication ‘Industry in

Avonmouth: A Guide to Pollution Management’. (Ref. 13-3). This publication

documents the activities of 12 potentially contaminating industries active in the


May 2014 Page 13-11

Avonmouth area in 2002. Three of these are located within approximately 1km

of the Proposed Development Site; these are the Terra Nitrogen (UK) facility,

Seabank 1 & 2 and the Sevalco plant. As the Sevalco plant is located closer to

the cooling water pipeline route than the Proposed Development Site, it has

been discussed in detail in later sections in the chapter.

13.4.14. Terra Nitrogen (UK) was the name of the chemicals manufacturing company

which operated until approximately 2008 on the land adjacent to the north of

the Proposed Development Site. The site was taken over by Terra Nitrogen

(UK) from ICI Chemicals in 1998 and produced ammonia which was used to

produce nitric acid for the fertilizer industry.

13.4.15. Seabank 1 & 2 is located adjacent to the southwest of the Proposed

Development Site, although the electrical connection corridor and part of the

DCO Site crosses this facility. It began commercial operation in March 2000

and comprises gas and steam turbines which supply electricity to the national

grid.

13.4.16. Prior to the development of Seabank 1 & 2, the site comprised Seabank Gas

Works, which was operated as a gas-from-naphtha production facility between

1963 and the 1970s (Ref. 13-4). Prior to development of Seabank 1 & 2, site

investigation works were completed which identified contaminated ground

within the Seabank 1 & 2 footprint. Remediation works were completed, as

part of the redevelopment planning consent, to remove soil and groundwater

contaminated with metals, benzene, toluene, ethylbenzene and xylenes

(BTEX) and sulphide from the Seabank 1 & 2 site. Areas of soil contaminated

with tar / hydrocarbon were also reportedly removed. It is reported that risk

assessment works demonstrated that the remediation was successful. Small

parts of the Seabank 1 & 2 site were not remediated such as below electricity,

gas and water mains due to physical and safety constraints.

13.4.17. The EA publication ‘Industry in Avonmouth’ (Ref. 13-3) discusses the

processes of Britannia Zinc, which was a zinc smelting plant which operated at

Avonmouth for over 70 years before its closure in 2003. Although the plant

was located over 2.5km to the south of the Proposed Development Site, it has

been included here due to the potential for airborne metal contamination

affecting the soil.

13.4.18. Historical mapping identified the development of a gas works to the southeast

of the CCR Site during the early 1970s. This site is still operational as

Avonmouth LNG Storage Facility.

13.4.19. Given the low-lying nature of the area, the development of all the surrounding

industrial sites would have required the importation of fill material to raise site


May 2014 Page 13-12

levels and provide suitable site surfaces, including the development of the rail

track in the centre of the southern boundary of the Proposed Development Site.

In addition, services, including water mains, gas mains and electricity pylons

have been developed across the Proposed Development Site. It is understood

that the gas mains were installed in drilled rather than trenched routes and

therefore it is unlikely that imported fill was used for these pipelines (Ref. 13-5).

13.4.20. During the site visit a significant amount of fly-tipped waste was noted in the

Proposed Development Site, predominately along the sides of the private track

running north/south through the centre of the Site (formerly part of Ableton

Lane). Pictures of the fly tipped waste are presented in Appendix I Part 2,

Volume II of this PEI report, and included materials such as baths, clothes,

demolition rubble, potential bound-asbestos roof panels, scrap metals, wood

and plastics.

Contamination

13.4.21. During the October / November 2013 GI, in general, no visual and/or olfactory

evidence of contamination of soils was identified. During logging of BH003, a

hydrocarbon type odour was reported between 4 and 6m depth. A total of 41

soil (including from where the odour was reported in BH003), 14 groundwater

samples and 4 surface water samples were scheduled for laboratory analysis.

13.4.22. An assessment of the results is given in the Phase II Report (Appendix I Part 4,

Volume II) which determined that no samples exceeded relevant Human Health

screening criteria. Minor exceedances of Controlled Waters screening criteria

were reported for metals arsenic, barium, copper, lead and selenium. These

are not considered likely to pose a significant risk to water quality. Alkaline

groundwater identified within the bedrock aquifer is considered likely to limit the

mobility of the metals species identified.

Recommendations include that construction and development workers should

be provided with appropriate personal protective equipment (PPE)

commensurate for earthworks. These should include, but are not limited to, the

use of gloves, overalls and eye protection particularly when in contact with

groundwater. Workers should also be made aware of the need for good

personal hygiene following contact with any soils during site works.

Geology

13.4.23. Geological mapping at 1:50,000 (Ref. 13-6) indicates the Proposed

Development Site and route of the electrical connection to be underlain by

Quaternary age Tidal Flat deposits consisting of normally consolidated soft silty

clay, with layers of sand, gravel and peat. The Envirocheck Report (Ref. 13-1)


May 2014 Page 13-13

for the Proposed Development Site classifies the hazard potential for both high

compressibility ground and running sands within these deposits as moderate.

13.4.24. Underlying the superficial drift cover, the bedrock comprises Triassic age

Mercia Mudstone Group described as dominantly red, less commonly green-

grey, mudstones and subordinate siltstones. Typically halite-bearing units in

some basinal areas and thin beds of gypsum/anhydrite are present in the

Mercia Mudstone Group, however they are likely to be absent in this area of

the UK.

13.4.25. Historical borehole data available on the British Geological Survey (BGS)

website (Ref. 13-5) for boreholes drilled within 500m to the south and west

boundary of the Proposed Development Site indicates the thickness of drift

cover to be approximately 10 - 15m. The thickness of the Mercia Mudstone

Ground is identified within these boreholes as approximately 35 - 45m,

overlying Carboniferous Coal Measures strata at depths of approximately 40 -

50m below ground level (bgl). The Envirocheck Report (Ref. 13-1) lists the area

as a non-coal mining area of Great Britain.

13.4.26. Substantial thicknesses of Made Ground are not anticipated at the Proposed

Development Site due to low levels of previous development, as identified on

historical mapping provided within the Envirocheck Report (Ref. 13-1). The

mapping shows that railway sidings were present at the north eastern end of

the Proposed Development Site until they were later dismantled. This area,

together with the former rail tracks in the northern section of the site, is likely to

be underlain by minor thicknesses of Made Ground.

13.4.27. Table 13-6 details the ground stability hazard information contained within the

Envirocheck Report.

Table 13-6: Summary of Ground Stability Hazards for the Proposed Development

Site and Electrical Connection

Geological Potential Hazard Classification

Potential for collapsible ground stability hazards No hazard

Potential for compressible ground stability hazards Moderate

Potential for ground dissolution stability hazards No hazard

Potential for landslide ground stability hazards Very low

Potential for running sand ground stability hazards Moderate

Potential for shrinking or swelling clay ground stability hazards

Low


May 2014 Page 13-14

13.4.28. Table 13-7 presents a summary of the geological strata encountered during the

GI.

Table 13-7: Summary of Site Geological Strata under the Proposed Development

Site

Strata Depth Range

(m bgl) Description

Topsoil 0 – 0.30 Firm dark brown slightly sandy clay with frequent rootlets. (Identified in BH004 only).

Tidal Flat Deposits 0.20 – 14.00

Firm, locally soft, fissured brown mottled grey silty clay. Occasional fragments of partially decomposed plant material and occasional PEAT.

Weathered Mercia Mudstone Group

9.00 – 17.50 Very stiff fissured dark reddish brown grey silty clay.

Mercia Mudstone Group

11.95 – base not proven

Extremely weak dark reddish brown mudstone interbedded with extremely weak to weak light greenish grey sandstone.

13.4.29. During the October / November 2013 GI, the GI contractors noted that running

sands had been identified at 5.10 to 8.60m bgl within the Tidal Deposits within

BH006. The occurrence of running sands was not widespread or consistent

within all boreholes.

Hydrogeology

13.4.30. The following EA hydrogeological classifications have been obtained for the

Proposed Development Site and the part of the Other DCO Land proposed for

the electrical connection, based on data included within the Envirocheck

Report:

• The superficial deposits likely to be encountered onsite are classified as

Unproductive strata;

• The Mercia Mudstone Group bedrock underlying the Site is classified as

Secondary B aquifer. Secondary B aquifers are defined as

‘predominantly lower permeability layers which may store and yield

limited amounts of groundwater due to localised features such as

fissures, thin permeable horizons and weathering. These are generally

the water-bearing parts of the former non-aquifers’;

• Groundwater Vulnerability mapping identifies that the Site is located on

a Non-Aquifer of negligible permeability; and

• The Site is not located within a Groundwater Source Protection Zone.


May 2014 Page 13-15

13.4.31. The Envirocheck Report does not identify any licensed groundwater

abstractions within 1km of the Proposed Development Site.

13.4.32. Groundwater was identified during drilling in all of the boreholes and was found

to be shallow, with initial strikes between 1 and 3m depth within the Tidal Flat

Deposits. In addition, a second strike was recorded from a gravel layer at

approximately 12m depth in BH001. As water was added during coring, it was

difficult to assess the strikes within the bedrock during drilling although several

thick sections of sandstone were identified within the mudstone. These were

screened and found to be water bearing.

13.4.33. Four wells had installations in the Tidal Flat Deposits (BH001- gravel section,

BH003, BH005 and BH006) and three within the bedrock (BH002, BH004 and

BH007).

13.4.34. Following the intrusive investigation and site levelling, two groundwater

monitoring rounds were carried out. The average depth to groundwater from

both rounds of the wells installed in the Tidal Flat Deposits was 2.21m bgl

(4.36m AOD) and 2.23m bgl (4.39m AOD) for those installed in the bedrock.

In-situ parameter testing of the groundwater was completed during purging of

the boreholes and prior to groundwater sampling. The full results are recorded

in Table A of the Phase II Report (Appendix I Part 4, Volume II of this PEI

Report).

13.4.35. The depth to groundwater has been used to infer the groundwater flow

direction and gradient for the Tidal Flat Deposits and the bedrock. Both strata

indicate a flow direction toward the north at a gradient of 0.08m (Tidal Flat

Deposits) and 0.08m (Bedrock). A groundwater contour plan is presented as

Figure 1 of the Phase II Report (Appendix I Part 4, Volume II of this PEI

Report).

Hydrology

13.4.36. The Severn Estuary is located approximately 0.5km to the northwest of the

Proposed Development Site. The Proposed Development Site itself is

predominantly flat and low-lying and poorly drained with frequent areas of

standing surface water and marshland. The land at the southern end of the

Proposed Development Site is identified on both recent and historical mapping

as Crook’s Marsh. Flood maps contained within the Envirocheck Report

indicate the Proposed Development Site to be susceptible to flooding from

rivers or sea in the absence of any defences (Flood Zone 3).


May 2014 Page 13-16

13.4.37. There are no recorded licensed and active surface water abstractions within

1km of the Proposed Development Site and the EA records no surface water

quality data for water bodies within 1km.

13.4.38. The Proposed Development Site is drained by several channels (minor rhines)

and a major channel (the Red Rhine) running from southeast to northwest

through the centre of the Proposed Development Site, which outfalls into the

Severn Estuary at New Pill Gout. It is understood that along with several of the

minor rhines, the Red Rhine is to be diverted to the northern boundary of the

Proposed Development Site by a third party, Severnside Distribution Land Ltd,

in advance of the Proposed Development. This diversion has therefore been

assumed as part of a future baseline for the Proposed Development.

13.4.39. Following the installation of monitoring wells in October / November 2013,

groundwater level recording pressure transducers were installed into three of

the ground monitoring wells for a 24 hour period to ascertain whether the

Proposed Development Site groundwater was tidally influenced. The data

obtained from the pressure transducers during the groundwater level

monitoring did not identify a tidal influence on the site groundwater.

Waste Facilities and Pollution Incidents

13.4.40. The Envirocheck Report lists waste facilities and those located within 1km of

the Proposed Development Site are summarised in Table 13-A in Appendix I

Part 1, Volume II of this PEI Report. One is considered to pose a potential

contamination risk to the site which is Crook’s Marsh Farm which was

operational between 1977 and 1979 located adjacent to the south west of the

Proposed Development Site and 20m southeast of the proposed electrical

connection route.

13.4.41. The Envirocheck Report and the EA Website, What’s in My Backyard feature

(Ref. 13-7), has been used to identify potentially contaminative pollution

incidents within 1km of the Proposed Development Site and electrical

connection. Two were identified within the vicinity of the Proposed

Development Site, both greater than 400m from the site and the details are

summarised in Table 13-B Appendix I Part 1, Volume II of this PEI Report.

Unexploded Ordnance

13.4.42. Due to the strategically important location of the Proposed Development Site,

in relation to Avonmouth Docks and the industrial complex, it is possible that

unexploded ordnance (UXO) exists at the Proposed Development Site.

13.4.43. The geophysical surveys used to assess the potential for UXO at the Proposed

Development Site were presented in ‘Report 3989 Geophysical Survey Report:


May 2014 Page 13-17

UXO Scanning, July 2013’ (Ref. 13-8). This report presents only information

on the location and strength of the anomaly which reflects the distribution of

magnetic sources within the shallow sub-surface and in most cases is

associated with ferrous material/objects. A definitive interpretation of the

anomalies was not included; however possible sources were identified as

discarded debris/objects, buried features/structures, and potentially certain

types of UXO (those that contain sufficient magnetic material to be detected).

A number of anomalies were detected, with interference from known buried

services such as pipelines also identified.

13.4.44. As described in the Chapter 15: Archaeology and Cultural Heritage, evidence

of aerial defence structures has been identified near the Proposed

Development Site. This provides further evidence that the area was considered

a potential target for bombing.

Ground Gas

13.4.45. Hazardous ground gases can be derived from both natural strata and man-

made ground conditions. Natural strata which produce hazardous ground

gases typically include organic rich substrates such as alluvium and peats, as

respiratory breakdown of the organic compounds releases carbon dioxide and

methane.

13.4.46. The geology of the Proposed Development Site and proposed electrical

connection corridor is understood to comprise Tidal Flat deposits. These

deposits may contain peat layers and fragments of partially decomposed plant

material. Hence there is a potential for ground gas generation associated with

these natural strata.

13.4.47. Hazardous ground gases can also be released from organic rich fill material

within Made Ground. Given the site history and borehole logs, there is not

considered to be a significant amount of Made Ground at the Proposed

Development Site. There is however a former landfill adjacent to the south of

the Proposed Development Site and to the east of the proposed electrical

connection corridor, which has the potential to release ground gases. During

December 2006 ground gas monitoring was undertaken from boreholes in this

landfill site by third party (Ref. 13-9) and encountered methane concentrations

of up to 97.7%. The Phase II Report (Appendix I Part 4, Volume II of this PEI

Report) notes that consideration should be given to the prevention of a gas

migration pathway being created through any placed fill material if the site is

raised.

13.4.48. Information from the Envirocheck Report (Ref. 13-1) indicates that the

Proposed Development Site and the electrical connection corridor are located


May 2014 Page 13-18

in an area where there is no risk from radon. Guidance on protective measures

for new buildings (Ref. 13-10) shows that the Proposed Development Site is

located in an area where no protective measures are required.

13.4.49. During the October/November GI, each of the seven boreholes was installed

with a ground gas monitoring well. During the monitoring (undertaken on 19

and 20 November 2013) each gas well was monitored for volatile organic

compounds (VOCs) and landfill gases, and the findings are summarised as

follows;

• No detectable concentrations of methane were identified;

• VOC levels were very low (less than 0.2 parts per million (ppm));

• The maximum concentration of carbon dioxide was 2.1%;

• The maximum carbon dioxide concentration (BH002) corresponded to a

depleted concentration of oxygen (12.3%);

• The flow rate was recorded as a negative value in all locations with a

maximum negative of 4.3 litres per hour; and

• The atmospheric pressure recorded during the two day monitoring

event fell from 1018 milibars (mbars) on the first day to 999mbars on

the second.

13.4.50. An assessment of this data is provided in the Phase II report (Appendix I Part

4, Volume II of this PEI Report) which concluded that the risk from ground gas

was very low, although this should be verified following further gas monitoring

rounds.

The Proposed Cooling Water Pipeline Corridor

13.4.51. The proposed cooling water pipeline corridor is approximately 3.5km long and

30m wide that extends from Seabank 1 & 2 to the Bristol WWTW, as illustrated

in Figure 13-1 (Volume III of this PEI Report). The routing of this corridor has

been assessed as part of this PEI Report.

13.4.52. The cooling water pipeline corridor will pass through predominantly flat land

with only minor changes in elevation. OS maps indicate that the ground level is

at an elevation of approximately 6m AOD.

13.4.53. A site visit for the proposed corridor was conducted by URS on the 18

November 2013, during which observations were noted on land use , potential

contaminative sources along the route, indications of contamination (e.g.

distressed vegetation or discolouration/sheens on surface waters), and

indications of ground instability.


May 2014 Page 13-19

13.4.54. Land uses within the proposed cooling water pipeline corridor are

predominantly agricultural and amenity based (including substantial stretches

of cycle pathways). Land uses directly adjacent to parts of the corridor

commonly include industrial or commercial usage. These land uses are

discussed in more detail below

13.4.55. Two sections of the cooling water pipeline were found to be inaccessible at the

time of the site visit: a short section (approximately 280m long) to the

southwest of the existing railway line and the short section within the Bristol

WWTW.

13.4.56. The proposed cooling water pipeline route was noted to cross a number of

shallow streams/rhines. Additional shallow streams or ditches were observed

close to the route. Where it was possible to observe these, no indications of

contamination were noted, with the exception of some discolouration limited to

a pipe discharging to a Stuphill Rhine. A shallow ditch containing water to the

immediate southwest of the current railway line (and to the immediate

northeast of the cooling water pipeline) had a sheen on it. Further observation

indicated this to be an organic derived platy sheen rather than a petroleum-

based mobile sheen.

13.4.57. Two areas of fly-tipping were observed, one alongside Chittening Road, the

other adjacent to the railway line. Only minor amounts of waste were observed

during the site visit (generally plastics including buckets).

13.4.58. No indications of ground instability were observed along the cooling water

pipeline corridor, which is to be expected since it is predominantly flat. It is

noted that given the changes in site history, some areas of infilling are

anticipated.

Site History and Contaminated Land Potential

13.4.59. The Envirocheck Report and site walkover were used to assess the history of

the cooling water pipeline corridor and the surrounding area. Table 13-C and

Table 13-D in Appendix I Part 1, Volume II of this PEI Report outline the history

of the proposed cooling water pipeline corridor and surrounding area and

further information about surrounding industrial uses is included.

13.4.60. In addition, the following land uses were noted during the site walkover:

• An aggregates facility was noted adjacent to the cooling water pipeline

approximately 300m south of Seabank 1 & 2. This is not shown on

maps therefore is considered to be relatively new. Heavy Plant was

observed working at this facility and therefore it is anticipated that the


May 2014 Page 13-20

site includes fuel storage, however this was not observable from the

pipeline route;

• A site adjacent to the aggregates facility could not be fully observed,

however heavy plant was observed working in this site and a solvent

type odour was noted during the site visit adjacent to this site. It is

therefore possible that some usage or storage of chemicals occurs at

this site; and

• A number of wind turbines were observed close to the cooling water

pipeline. It is anticipated that utilities such as a transformer and cabling

will be associated with these structures; however the potential for

contamination is considered to be low.

13.4.61. The cooling water pipeline will connect to the Proposed Development Site via

Seabank 1 & 2. To avoid repetition, see section 13.4.13 to 13.4.20 for

discussion of the Seabank 1 & 2 site and immediate surroundings.

Geology

13.4.62. The BGS website / online borehole viewer (Ref. 13-7) and the Envirocheck

data sheet were used to assess the likely nature of the geological sequence

beneath the cooling water pipeline route. These resources indicate that the

following material is present:

• Historically the majority of the proposed cooling water pipeline is

located on land reclaimed from the Severn Estuary. Made Ground is

likely to be present in those areas where previous development has

taken place. Along the route of the cooling water pipeline several

sections comprise previously developed land and as such are likely to

include Made Ground. The locations of previously developed sections

are discussed in the site walkover section;

• The superficial geology below the cooling water pipeline consists of

Tidal Flat Deposits, which comprise consolidated soft silty clay of the

Holocene epoch; and

• The bedrock sequence underlying the cooling water pipeline is

indicated to comprise Mudstone of the Mercia Mudstone Group,

consisting of dominantly red, less commonly green-grey, mudstones

and subordinate siltstones with thick halite-bearing units in some

basinal areas. Thin beds of gypsum/anhydrite are widespread;

sandstones are also present.

13.4.63. Publicly available borehole records were accessed via the BGS online borehole

viewer. Three boreholes were assessed:


May 2014 Page 13-21

1. Reference ST58SW124: located 600m from Seabank 1 & 2;

2. Reference ST58SW8 located on the route of the cooling water pipeline

1.24km along the pipeline route, measured from Seabank 1 & 2; and,

3. Reference ST58SW122 located 2,620m along the cooling water

pipeline and 190m to the west.

13.4.64. The available logs indicate the superficial deposits in the vicinity of the cooling

water pipeline largely comprise interbedded mudstone, sandstone and

siltstone. These deposits are recorded on the borehole logs as ‘drift’. Red and

green marl, part of the Keuper series (now part of the Mercia Mudstone Group)

was encountered between depths of approximately 18m and 55m bgl. Below

this, Upper Coal Measures mudstones of the Carboniferous Supra Pennant

Group are found to 142 m bgl.

Hydrogeology

13.4.65. As indicated on borehole log ST58SW122, water was encountered between

30.50m and 32.00m bgl in the Mercia Mudstone group unit. The resting water

level was recorded at 9.14m bgl. No resting water level was provided in the

other logs viewed.

13.4.66. The Tidal Flat Deposits in the area of the cooling water pipeline corridor, as

shown on mapping presented within the Envirocheck Report for the Proposed

Development Site, are defined as unproductive strata. Unproductive strata are

‘rock layers or drift deposits with low permeability that have negligible

significance for water supply or river base flow’.

13.4.67. The mudstone bedrock underlying the cooling water pipeline site is classed as

a Secondary B aquifer.

13.4.68. The area surrounding the cooling water pipeline has a groundwater

vulnerability zone classification of ‘non aquifer (negligibly permeable)’.

13.4.69. The cooling water pipeline corridor is not situated on any groundwater source

protection zones, as designated by the EA. The Envirocheck Report shows

three licensed goundwater abstractions within 1km of the proposed cooling

water pipeline corridor, all of which are at the Rhodia UK Limited/ Rhodia

Organique Fine Limited site, which has since ceased operation.

Hydrology

13.4.70. A number of surface waters are present around the proposed cooling water

pipeline corridor, some of which cross the route. These are generally shallow

streams, or rhines and include ‘Stuppill Rhine’, and ‘Salt Rhine’ located south


May 2014 Page 13-22

of the railway crossing, and one named ‘Mere Bank Rhine’ near the Bristol

WWTW. All local streams are assumed to drain to the River Severn Estuary.

13.4.71. The Severn Estuary is the largest surface water feature in the vicinity of the

cooling water pipeline, 550m to the west.

13.4.72. South of the railway where the cooling water pipeline is likely to cross, there

are four ponds. The closest pond is approximately 10m from the cooling water

pipeline. These could not be viewed during the site visit due to access

restrictions in force at the time.

13.4.73. Near the Bristol WWTW, approximately 25m to the west of the cooling water

pipeline, there are 3 reservoirs.

13.4.74. There are no recorded licensed and active surface water abstractions within

1km of the water cooling pipeline and the EA records no surface water quality

data for water bodies within 1km.

13.4.75. Further information on the hydrological setting is provided in Chapter 14: Flood

Risk, Hydrology and Water Resources.

Ground Stability

13.4.76. Table 13-8 details the ground stability hazard information contained within the

Envirocheck Report.

Table 13-8: Summary of Ground Stability Hazards within the Cooling Water

Pipeline Corridor

Geological Potential Hazard Classification

Potential for collapsible ground stability hazards No hazard

Potential for compressible ground stability hazards Very low - moderate

Potential for ground dissolution stability hazards No hazard

Potential for landslide ground stability hazards Very low

Potential for running sand ground stability hazards Very low - moderate

Potential for shrinking or swelling clay ground stability hazards

Low

Waste Facilities and Pollution Incidents

13.4.77. A number of landfills and waste management facilities are reported within 1km

of the pipeline, the closest being 65m away, and these have been summarised

in Tables 13-F, 13-G and 13-H in Appendix I Part 1, Volume II of this PEI

Report.


May 2014 Page 13-23

13.4.78. The Envirocheck Report has been used to identify potentially contaminative

pollution incidents in the area of the proposed cooling water pipeline corridor

and these have been summarised in Table 13-I in Appendix I Part 1, Volume II

of this PEI Report. Note that incidents considered more relevant to the

Proposed Development Site are included in the appropriate section above. One

incident was recorded within 10m of the proposed cooling water pipeline

corridor when a significant impact to water and land from oils and fuels was

registered in February 2008.

Unexploded Ordnance

13.4.79. As for the Proposed Development Site as described above, due to the

strategically important Avonmouth Docks and industrial areas, it is possible that

UXO exists along the cooling water pipeline. As described in the Chapter 15:

Archaeology and Cultural Heritage, evidence of aerial defence structures has

been identified in the area. This provides further evidence that the area was a

target for bombing.

13.4.80. In addition, due to the proximity of the cooling water pipeline to the former

munitions factory and shell filling facility (potentially immediately adjacent within

the Chittening Industrial Estate, as described in Appendix I Part 1, Volume II of

this PEI Report, it is possible that ordnance remains in the ground from those

activities. As described above, a suspected mustard gas shell was uncovered

in 2012 during groundworks in the former Britannia Zinc smelting works

(approximately 250m southwest of the proposed cooling water pipeline

corridor). Storage magazines are labelled in fields close to the cooling water

pipeline on an inter-war aerial photograph.

13.4.81. The possibility of encountering UXO along the cooling water pipeline will be

considered as part of the construction management plan that will be prepared.

Ground Gas

13.4.82. As outlined above, hazardous ground gases can be derived from both natural

strata and man-made ground conditions.

13.4.83. Hazardous ground gases can also be released from organic rich fill material.

Given the industrial history of the cooling water pipeline route, including current

and former landfills, there is considered to be a potential for the release of

hazardous ground gases.

13.4.84. As outlined above, mapping indicates that the Proposed Development Site and

the proposed route of the cooling water pipeline are located in an area where

there is no risk from radon.


May 2014 Page 13-24

Preliminary Conceptual Site Model

13.4.85. The above baseline data regarding the Proposed Development Site and

proposed electrical connection corridor and proposed cooling water pipeline

corridor has been used to prepare a preliminary Conceptual Site Model (CSM)

to identify potential source-pathway-receptor pollution linkages.

Sources

13.4.86. The Proposed Development Site is believed to have undergone little previous

development as and such potential contamination sources are from the existing

railway, the area of historical farm buildings, the existing track, fly tipping and

surrounding land uses.

13.4.87. The proposed cooling water pipeline corridor passes through areas with a

variety of previous site uses and as such the potential contamination sources

are potentially numerous and variable along the extent of the corridor.

13.4.88. Ground gases may be released from underlying geology including the natural

organic-rich strata and Made Ground or filled areas.

Receptors

13.4.89. The potential contamination receptors are considered to include:

• Future site users i.e. staff and visitors of the proposed development;

• Construction and maintenance workers;

• Adjacent site users;

• Rhines; and

• The Severn Estuary.

Pathways

13.4.90. The potential pathways between the sources and receptors are considered to

include:

• Human ingestion of soil;

• Human dermal contact with soil

• Human inhalation of volatile contaminants via volatilisation from soil

and/or groundwater and subsequent vapour intrusion in to buildings or

dispersion into outdoor air;

• Human inhalation of soil derived dust via surface dust release outdoors

and/or tracked back soil into buildings;


May 2014 Page 13-25

• Leaching from contaminated soils to groundwater and subsequent

migration within groundwater to and inflow into identified surface

waters;

• Migration of contaminated groundwater to and inflow into identified

surface waters; and

• Migration of ground gases into buildings.

Summary of Baseline Information

13.4.91. Table 13-9 provides a summary of the site sensitivity for the DCO Site based

on the information detailed above.

Table 13-9: Proposed Development Site Environmental Sensitivity

Parameter Receptor Sensitivity Reasoning

Groundwater Low Tidal flat deposits are classified as unproductive strata whilst the underlying mudstone bedrock is classified as Secondary B Aquifer. The Proposed Development Site is not situated on any groundwater source protection zones. Licensed groundwater abstractions in the area are limited to industrial usage with no potable water abstractions identified.

Surface Water High The Severn Estuary is approximately 400m from the Proposed Development Site. The Proposed Development Site is crossed by several small streams, or rhines, including the Red Rhine (which will require diversion works). This network of rhines in the area discharges to the Severn Estuary. No recorded licensed and active surface water abstractions were identified within 1km of the Site.

Moderate Following the diversion of the Red Rhine to the northern perimeter of the Proposed Development Site, the sensitivity to potential effects is considered to be reduced (due to the increase in distance from the site activities).

Environmentally Sensitive Receptors

Low (Moderate for the Severn Estuary)

The Severn Estuary is designated as a SAC, SPA, Ramsar site and SSSI and is approximately 400m from the Site.

An area of Adopted Green Belt is present approximately 550m east of the Proposed Site.

Human Receptors

Low The DCO Site is in a commercial area and the closest residential properties are approximately 1.1km south east of the Site.

High Groundworks will be required during construction and as such the workforce may be in direct contact with soil and groundwater. During the operational phase there should be no requirement for the workforce to be in direct contact with soil or groundwater.


May 2014 Page 13-26

13.4.92. Table 13-J and 13-K in Appendix I Part 1, Volume II of this PEI Report present

a list of potential contamination present on the Proposed Development Site and

associated infrastructure, based on the areas of development and historic land

uses identified. These are based on guidance in the NHBC/EA document

Guidance for the Safe Development of Housing on Land affected by

Contamination (Ref. 13-11).


13.5.1. A number of impact avoidance measures have been incorporated into the

design. These measures have therefore been taken into account during the

assessment presented in this chapter.

13.5.2. The Proposed Development incorporates a minimum 8m buffer strip alongside

the southern side of the realigned Red Rhine for access by the LSIDB. This

should inherently reduce pollution risks during construction, once the

Generating Station Site has been raised, by creating a natural setback from

this watercourse.

13.5.3. The Generating Station Site will be raised to a maximum 8.5m AOD, which

equates to an average 2.2m above current ground levels for this part of the

Site. This material will be tested prior to accepting it onsite and will minimise

the need for excavation of existing soils onsite. Where possible, any excess

material from the installation of the cooling water pipeline will be used onsite as

part of the land raising.

13.5.4. Chapter 5: Enabling Works and Construction provides an overview for the

methods of installation for the proposed cooling water pipeline. A number of

potential risks associated with diverting the main gas pipeline beneath the

Proposed Development Site and crossing the Government Pipeline and

Storage System (GPSS) oil pipelines have been mitigated through design and

should pose negligible risks to this 3rd party infrastructure and the environment.

These are therefore not discussed further.

13.5.5. Additional mitigation measures and industry-standard control measures are

discussed in Section 13.6 to minimise potential effects on ground conditions.


Site Preparation and Construction Phase

13.6.1. During the construction phase of the Proposed Development and associated

infrastructure there are a number of potential effects on the geology,

hydrogeology or land that may have a direct or indirect effect on sensitive

receptors.


May 2014 Page 13-27

13.6.2. As detailed in Chapter 5: Enabling Works and Construction, it will be a

Requirement that the Principal Contractor will prepare a site wide CEMP for the

development. This document will set out the management, monitoring, auditing

and training procedures that will be in place to ensure compliance with the

applicable regulations.

13.6.3. All construction works undertaken will be carried out in accordance with

procedures and mitigation measures outlined in the CEMP, which will be

produced by the selected contractor before the commencement of any works.

13.6.4. The principal effects and the required mitigation measures that will be

embedded within the design and management of the Proposed Development

are discussed in the following sections. The potential sources, pathways and

receptors for the site preparation and the construction phase of the Proposed

Development and associated infrastructure are presented in Table 13-10.

Table 13-10: Potential Sources, Pathways and Receptors for Consideration

during the Site Preparation and Construction Phases

Category Description

Sources Soil and groundwater impacted from general construction activities/site preparation (the Proposed Development Site and the cooling water pipeline)

New contamination pathways created by the construction of piled foundations (the Proposed Development Site) / below ground structures (the Proposed Development Site and the cooling water pipeline)

Localised soil and groundwater contamination in Made Ground and underlying strata (as identified in onsite contamination source tables)

Off-site soil and groundwater contamination migrating on-site

Pathways To Human health Receptors:

• Vapours – Migration of vapours through made ground into above ground buildings (temporary construction buildings or cabins).

• Vapours – Migration of vapours through made ground into above ground buildings (permanent buildings – the Proposed Development Site only, not the cooling water pipeline)

• Particulate – Ingestion, inhalation and dermal contact with soil particulates.

• Permeation – Migration of contaminant substances through plastic potable water supply pipes (the Proposed Development Site only – not the cooling water pipeline).

• Gas – Migration of ground gas through made ground into above ground buildings (temporary construction buildings or cabins).

• Gas – Migration of ground gas through made ground into above ground buildings (permanent buildings – the Proposed Development Site only, not the cooling water pipeline)

• Human exposure to soils during construction and excavation works and movement of soils offsite.


May 2014 Page 13-28

Category Description

To Controlled Waters Receptors:

• Leaching – Migration of contaminant substances from soils into perched water and groundwater,

• Migration of affected perched water and groundwater, if present, to surface water.

• Historical, current and proposed service routes which may act as preferential pathways for contaminant migration.

To Environmentally Sensitive Areas:

• Leaching – Migration of contaminant substances to surface waters of the Severn Estuary (designated under various schemes including SAC, SPA, Ramsar and SSSI, and)

• Leaching – Migration of contaminant substances to soil and groundwater of Adopted Green Belt.

Receptors Human Health receptors:

• Workers onsite during construction works.

• Workers onsite once the development has been built (the Proposed Development Site only, not the cooling water pipeline).

• The general public and staff visiting site once it has been developed (both the Proposed Development Site and the cooling water pipeline)

• Nearby workers within local commercial properties.

Controlled Waters Receptors:

• Various surface water ponds and drains / rhines.

• Severn Estuary.

Environmentally Sensitive Areas:

• Surface waters and inter-tidal mud flats of the Severn Estuary

Soil and Groundwater Contamination

13.6.5. Based on the results of the baseline assessment that has been completed for

this PEI Report, it is considered that the potential magnitude of the change

brought about by construction will be Medium. This is based on the risks to

surface water (high environmental sensitivity) rather than groundwater (low

environmental sensitivity) as it is feasible that existing soil and groundwater

contamination could enter the surface waters either through mobilisation from

soil and groundwater or through direct loss into to surface waters that are

present within the Proposed Development and associated infrastructure.

13.6.6. Materials management procedures such as the creation of bunded storage

areas and use of water storage lagoons or water treatment plants, as

appropriate, will be used to minimise the potential for excavated soil or pumped

groundwater to enter the surface waters. A Materials Management Plan


May 2014 Page 13-29

(MMP) and CEMP will be a requirement of the Proposed Development and will

develop the mitigation measures in the final ES further. The predicted effect of

direct loss to surface waters is therefore considered to be of negligible

significance.

13.6.7. With regard the potential for the works to mobilise contaminants through soil

and water to the surface waters, or to groundwater it is considered that the

predicted effect of the development construction on the ground conditions will

be negligible in the Proposed Development Site as no significant

contamination was identified during the GI.

13.6.8. Intrusive investigation has not yet been undertaken for the proposed cooling

water pipeline corridor; it is anticipated this would be undertaken post-consent,

prior to the installation of the pipeline and any contamination would be

remediated. These further investigation and assessment works will be

undertaken in accordance with the requirements of CLR11, GPLC1-3, GP3 and

any specific Requirements agreed as part of the DCO prior to site construction

works commencing.

13.6.9. Contamination within soils has the potential to adversely affect the health of

construction workers; this is considered to have the ability to lead to a Medium

magnitude of change without proper mitigation. Health and Safety mitigation

measures, appropriate to the chemical composition of the ground (and potential

groundwater), will be evaluated and implemented to protect the construction

workers’ health. As such, any existing contamination is expected to have a

negligible significance to construction workers provided that the appropriate

mitigation measures are adopted such as the appropriate use of PPE, hygiene

practices and decontamination units, if required. The clear exception to this

would be the potential presence of UXO and / or chemical warfare (CW) agents

(e.g. mustard gas) which are discussed in more detail in the UXO section

below.

13.6.10. Land raising works will be an integral part of the Proposed Development Site

construction to achieve the proposed Site formation levels to mitigate potential

flood risk as outlined in Chapter 14: Flood Risk, Hydrology and Water

Resources. The potential magnitude of change is considered to be Medium on

surface waters without adequate mitigation, which is discussed below.

13.6.11. Earthworks will be carried out with due regard to the current regulatory regime

for waste management. Material arriving on-site will be tested at an

appropriate frequency (depending on its source) to confirm that it is suitable for

use. Bulk materials such as topsoil and fill material will be stored in designated

areas away from watercourses and covered to prevent erosion. The 8m

maintenance access strip proposed alongside the realigned Red Rhine will


May 2014 Page 13-30

increase the distance of stockpiles from the main identified watercourse.

Specific guidance in dealing with silt arising from construction activities is

contained within PPG5, which will be taken into account within a CEMP.

13.6.12. Site materials will be reused to level the Proposed Development Site where

possible; for example any surplus soil from the trench for the proposed cooling

water pipeline could be used as part of the land raising for the Proposed

Development Site. The procedure for managing the re-use of soils will be

documented in a MMP which will be produced in general accordance with

CLAIRE Code of Practice ‘The Definition of Waste: Development Industry Code

of Practice’, 2011 (CLAIRE, 2011).

13.6.13. Where surplus soil requires disposal, i.e. it is not deemed suitable for re-use, it

will be disposed of to an appropriate, licensed landfill facility, in accordance

with current Duty of Care responsibilities and other statutory requirements. As

required by the Landfill Directive, inert, non-hazardous and hazardous waste

will require pre-treatment prior to disposal.

13.6.14. Prior to disposal, soil will need to be characterised following the methodology

described in the EA publications ‘Framework for the Classification of

Contaminated Soils in Hazardous Wastes’, version 1 (Ref. 13-12) and

‘Guidelines on sampling and testing of wastes to meet landfill waste

acceptance procedures’ version 1. (Ref. 13-13).

13.6.15. Taking these measures into account, the predicted effect on surface water is


Storage of Potentially Contaminating Materials and Accidental Spillage

13.6.16. During construction there is potential for accidental spillage or vandalism to

result in a release of contaminants from vehicles, refuelling areas, storage

tanks, plant and machinery. Contaminants released could be chemicals, oils,

hydrocarbons or construction materials, and have the potential to enter the

sub-surface. This could detrimentally affect soil and groundwater quality. This

in turn could subsequently affect the sensitive surface water receptors

identified at the DCO Site.

13.6.17. The magnitude of the change to the land due to accidental spillage of fuels or

other contaminants from construction activities is dependent on the frequency

and size of the spillage. However, a spillage would be likely to present a

Medium magnitude of change on identified receptors during the construction

phase prior to mitigation.

13.6.18. To minimise the risk of accidental fuel and chemical spills, the following

mitigation measures will be employed:


May 2014 Page 13-31

• Oils and hydrocarbons will be stored in designated locations with

specific measures to prevent leakage and release of their contents,

including the siting of storage areas away from surface water drains, on

an impermeable base with an impermeable bund that has no outflow

and of adequate capacity to contain 110% of the contents;

• Wherever possible, stationary construction plant and machinery will

have drip trays beneath oil tanks/engines/gearboxes/hydraulics, which

will be checked and emptied regularly via a licensed waste disposal

operator;

• Installation of oil interceptors at the point where site surface water runoff

enters the Red Rhine, as appropriate;

• An emergency spillage action plan will be produced, which site staff will

be required to have read and understood. On-site provisions will be

made to contain a serious spill or leak through the use of spill kits,

booms, bunding and absorbent material; and

• All construction works will be carried out in accordance with site

specific method statements which will cover storage and use of

chemicals and fuels during construction. These will be in accordance

with regulatory guidance (e.g. EA pollution prevention guidelines) and

will be agreed in advance with the EA, SGC and BCC. It is proposed

that standard duties of care are employed with regard to delivery, use

and storage of potentially contaminating materials and liquids (bunded

storage platforms, control of substances hazardous to health (COSHH)

assessments and safety inductions etc.).

13.6.19. There will also be a minimum of a 2m buffer outside of the 8m easement along

the Red Rhine (10m in total) during construction to reduce pollution risks,

resulting in any chemicals or liquids being stored a minimum of 2m from the

edge of the (8m wide) maintenance strip. There will be no storage of bulk

materials or potential contaminants in this area.

13.6.20. It is anticipated that the implementation of the above, as well as a site specific

method statement and CEMP, will render the potential effects to be of

negligible significance.

Asbestos

13.6.21. Asbestos is a common contaminant within Made Ground fill materials, and was

included within the suite of ‘determinands’ measured during the GI for the

Proposed Development Site and will be considered during any investigation of

the proposed cooling water pipeline route. The GI soil analysis did not identify


May 2014 Page 13-32

any asbestos containing materials (ACM), although given the widespread fly-

tipping present on the Development Site, it is possible that ACM are present.

The magnitude of change is considered to be Medium-High depending on the

level of asbestos present.

13.6.22. Should the presence of asbestos be identified in any pre-construction testing,

then appropriate measures will be implemented to mitigate the risks in

accordance with the Hazardous Waste Regulations (EA PPGs) and with

adherence to relevant Health and Safety guidelines. The predicted effects

following implementation of appropriate mitigation measures are considered to

be of negligible significance.

Disturbance of Dust and Silt

13.6.23. Dust and silt could resulting from soil disturbance during construction activities

may arise as a result of the movement of potentially contaminated soil by

construction machinery. This could result in an increase in suspended solids

i.e. the silting up of surface waters, or may have adverse effects on the health

of construction workers and the general public. The potential magnitude of

change is considered to be Medium.

13.6.24. Mitigation of potential dust effects that will be implemented are discussed in

further detail within Chapter 11: Air Quality.

Geotechnical Considerations

13.6.25. The required foundation design for the Proposed Development Site has not yet

been determined and will be chosen at the detailed design stage after receipt

of the DCO. Geo-environmental site investigation of the construction footprint

areas has been undertaken in order to establish the most appropriate

foundation design solution(s). At the time of writing this PEI Report, the

geotechnical data from this investigation is not yet available.

13.6.26. Depending on the final design, limited geo-technical testing may also be

required for the cooling water pipeline.

13.6.27. The requirements for a piled foundation solution will be dictated by the

observed ground conditions and the result of appropriate geotechnical testing

and design. Selection of a pile type / construction method will be based on

consideration of the technical requirements for supporting the building loads

and the potential for creating a preferential pathway for contaminant migration

through the underlying geological strata units. CFA piling is currently the

preferred piling method and is likely to be required for the turbine buildings,

HRSG buildings, and cooling water pump pits, although other structures such

as the peaking plant may also require piling.


May 2014 Page 13-33

13.6.28. Construction of large structures over Made Ground and / or unconsolidated

superficial deposits has the potential to result in settlement and subsidence of

the ground over time. The magnitude of such a change is considered to be

High given the potential outcome of settlement and subsidence of the

development.

13.6.29. Appropriate foundations will be designed at the detailed design stage and

informed by the outcome of the on-going Phase 2 geotechnical intrusive

investigation at the Proposed Development Site. New buildings will be

constructed with suitably designed foundations to ensure that the long-term

settlement of the building will occur within acceptable limits. Through

implementation of appropriate foundation design and possible ground

improvement, residual effects associated with settlement and subsidence are

considered therefore considered to be of negligible significance.

13.6.30. Construction of deep piles or foundations has the potential to create

preferential pathways for contaminant migration. However, no significant

contamination was identified during the GI and the significance is therefore

considered to be negligible. Should currently unidentified contamination be

identified, and the creation of a pathway be plausible and lead to a complete

source-pathway-receptor linkage, then foundation design will be used to

minimise the potential for this to occur. This will be in accordance with the

requirements of the EA ‘Piling and Penetrative Ground Improvement Methods

on Land Affected by Contamination’ document (Ref: 13-15).

13.6.31. Aggressive ground conditions such as elevated sulphate concentrations and

low pH values in soil and groundwater have the potential to cause significant

degradation to sub-surface concrete structures. As above, the potential

magnitude of change is considered to be High, due to the potential outcomes

from loss of integrity of concrete foundations. With reference to the relevant

Building Research Establishment (BRE) guidance, the required composition of

concrete can be selected to reduce the effect on sub-surface building materials

to negligible.

Ground Gas

13.6.32. The magnitude of change with regards to ground gas is considered to be Low

given the short term nature of the construction works and therefore exposure to

the receptor (workers). The effect of ground gas at this stage is predicted as

being of negligible significance, on the basis that the construction of the

Proposed Development and cooling water pipeline is unlikely to exacerbate

ground gas conditions.


May 2014 Page 13-34

13.6.33. It is however recognised that the presence of ground gas may pose restrictions

on the construction of the Proposed Development. It is unlikely to pose

restrictions on the construction of the cooling water pipeline given that no

permanent buildings are likely to be required. The magnitude of the change

from these restrictions is considered to be Low.

13.6.34. The GI included monitoring for the presence of ground gases and the

assessment identified a very low risk but recommended further monitoring to

confirm this although currently it is considered that the effect on the Proposed

Development Site is negligible. The potential for generation of ground gas

from Made Ground materials underlying the DCO Site represents a potential

long-term negligible to minor adverse effect to the health of site users and to

the development. This effect will be local, i.e. it will only be present within

buildings on site, however is likely to be permanent whilst the buildings remain.

13.6.35. In addition the radon risk has been assessed as low for the DCO Site.

Underground Structures

13.6.36. During the construction phase, there are a number of constraints relating to

existing operations and services in the vicinity of the DCO Site. The most

significant constraints are the existing high pressure gas mains and an oil

pipeline that cross the proposed cooling water pipeline route. There are also

overhead electricity cables and underground gas pipeline and water main that

cross the Proposed Development Site. Construction works around these

features will be undertaken in close consultation with the utility owners and

involving the input of specialist contractors as appropriate.

13.6.37. Underground obstructions such as existing service lines are known to be

present beneath points along the proposed route of the cooling water pipeline.

Of particular environmental significance is the presence of hydrocarbon

transfer pipes that cross the cooling water pipeline route. These are below

ground at the point at which they cross the cooling water pipeline. Accidental

disturbance of these structures (particularly where buried below ground) could

result in the loss of hydrocarbon product from these pipelines. BCC has

commented on the presence of these pipelines and has noted that specialist

contractors will be required for works in the pipeline vicinity. Consent from the

Crown is required prior to this work commencing.

13.6.38. On the basis of the sensitivity of surface water receptors and the presence of

the hydrocarbon pipelines, the potential magnitude of change is considered to

be High.


May 2014 Page 13-35

13.6.39. Prior to the commencement of excavation works appropriate steps including a

detailed survey of the services locations and depths will be taken to ensure that

construction activities do not disturb any live services.

13.6.40. Assuming that service clearance procedures are followed and an appropriate

management procedure is developed and implemented by appropriate

specialist contractors, the effect on the various existing underground structures

is considered to be of negligible significance.

Unexploded Ordnance (UXO)

13.6.41. Encountering UXO during piling and excavation represents a potential major,

albeit unlikely, short-term adverse effect to the safety of construction workers.

A UXO study has been undertaken for the Proposed Development Site, and

may be a requirement for the proposed cooling water route after receipt of the

DCO, and prior to construction. Given the risks from both historical aerial

bombing and the former munitions factory, further assessment of the risks on

the cooling water pipeline route will be required after receipt of the DCO and

prior to construction. The magnitude of the change associated with

encountering UXO is considered to be High.

13.6.42. Commissioning of an UXO desk study report, prior to construction, will assess

the risk of encountering UXO on site and recommend any mitigation measures

required to render potentially adverse effects negligible. Such mitigation

measures may include:

• Explosive Ordnance Safety and Awareness Briefings for personnel

conducting intrusive works;

• Unexploded Ordnance Site Safety Instructions for site personnel;

• Presence of an Explosive Ordnance Disposal Engineer on site to

supervise open excavations; and

• Down-hole intrusive magnetometer surveys of all deep intrusive works

and target investigation of suspect anomalies.

13.6.43. The potential magnitude of the severity / harm is likely to be extremely high, but

the likelihood of occurrence is typically very low. The most applicable approach

to manage these potential risks is to further reduce the likelihood of occurrence

through appropriate investigation ahead of construction work. Following this

mitigation, such as the removal of identified UXO, where required, and taking

into account the low risk of occurrence, the significance of this effect is



May 2014 Page 13-36

Operational Phase

13.6.44. The assessment of land contamination in respect to new development is based

on a “suitable for use” approach. Any risk assessment, remediation and

verification works that are required will be agreed, implemented and validated

as part of the pre-construction and / or construction phase and as such any

issues will have been dealt with prior to the operational phase.

13.6.45. Operational phase effects associated with land contamination are limited to the

storage and use of potential contaminants on site, i.e. the potential for further

land contamination to occur through the operation of the development. The

sensitivity of the receptor will be lower for this phase, as it is understood that

the Red Rhine will have been diverted, and there will be no requirement for

works within the cooling water pipeline corridor. However given that bulk

chemical storage will occur on the Site (for the distillate storage and water

treatment plant for example), the potential magnitude of change is Medium.

13.6.46. The Proposed Development will use similar bulk materials to those already in

use at Seabank 1 & 2. The bulk chemical storage inventory for Seabank 1 & 2

(Ref. 12-16) indicates that bulk storage currently includes distillate, acids (e.g.

sulphuric acids), treatment chemicals (e.g. sodium chlorite, ammonia solution,

and hydrazine), chemical inhibitors (e.g. algaecide, antifoam etc.), and

hydrocarbons (e.g. lubricating oil, transformer oil).

13.6.47. Suitable mitigation measures will be taken to protect controlled waters from the

release of chemicals, distillate and oils in accordance with the requirements of

the Environmental Permit for the operational plant and EA guidance and best

practice. These measures will comprise the following:

• Fuels will be stored in tanks designed specifically for purpose, with

measures to prevent leakage and release of their contents, for example

siting of tanks and other oil storage away from surface water drains, on

an impermeable base with an impermeable bund that has no outflow

and is of adequate capacity to contain 110% of the contents;

• Installation of oil interceptors at the point where site surface water runoff

enters the Red Rhine;

• An emergency spillage action plan will be produced, which site staff will

be required to have read and understood. On-site provisions will be

made to contain a serious spill or leak; and

• Site security will be such to prevent vandalism and deliberate release of

contaminants to soil and groundwater.


May 2014 Page 13-37

13.6.48. With the above mitigation measures in place the significance of this potential

effect is considered to be minor adverse as the operator of the plant has an

obligation under the Environmental Permit to prevent contamination of the site

during its operation and eventual decommissioning and closure.

13.6.49. The Proposed Development will require an Environmental Permit from the EA

for it to be able to operate. Regulation 12 of the Environmental Permitting

Regulations 2010 requires that “A person must not, except under and to the

extent authorised by an environmental permit; operate a regulated facility; or

cause or knowingly permit a water discharge activity or groundwater activity’”.

Management of operational phase risks will be undertaken and regulated under

the Environmental Permit. This will include appropriate storage, use and

disposal of hazardous materials used on the site.

13.6.50. The effects associated with the supply and discharge of cooling water is

considered in detail in Chapter 14: Flood Risk, Hydrology and Water

Resources. The cooling water supply will be treated a water treatment plant.

The magnitude of change associated with leakage from the proposed cooling

water pipeline is considered to be Medium, given that the water is designed

only to achieve the effluent discharge standards from Bristol WWTW. The

likelihood of such leakage however is considered to be low given that the

pipeline will be of a new construction and tested prior to use. Bearing this in

mind the operational phase land quality effects are therefore assessed as

negligible for the Proposed Development Site and the cooling water pipeline.

Decommissioning

13.6.51. Decommissioning of the Proposed Development Site and associated

infrastructure would require a MMP, method statements and a site closure

plan. These would be used to mitigate the risks of additional ground

contamination from the decommissioning phase. The risks associated with

spillages and contamination are considered similar to the construction phase,

although to a lesser extent and shorter in duration.

13.6.52. It is noted however that the main difference between construction and

decommissioning is the presence of process chemicals on site. It is feasible

that contamination could be released from the plant during

dismantling/demolition. The potential magnitude of change is therefore

considered to be high. All tanks will be drained of stored materials and plant

will be tested to ensure that there are no residual chemicals and it is clean prior

to dismantling. It is therefore considered that the significance of the effect is

likely to be negligible.


May 2014 Page 13-38

13.6.53. In addition, in order to surrender the Environmental Permit, the permit holder is

required to provide sufficient evidence to the EA to demonstrate that the

operation of the permitted facility has not caused degradation of the soil or

groundwater conditions at the DCO Site. In the unlikely event that they have

caused degradation the operator would be required to remediate the land and

therefore mitigate any effect.

13.6.54. The risks associated with the decommissioning phase for ground conditions

are therefore considered to be negligible.


13.7.1. The Proposed Development is proposed to be constructed on previously

undeveloped land, thus only surrounding land uses could have affected the

Proposed Development Site soil and groundwater quality. However, the

associated infrastructure (cooling water pipeline) is likely to encounter affected

land due to the historic land use.

13.7.2. A range of potential contaminants have been identified for the previous land

uses of the land through which the associated infrastructure is planned to be

routed. Standard mitigation measures of detailed site investigation, risk

assessment and remediation design and implementation will be employed

where required. This approach is consistent with EA / Defra Contaminated

Land Report 11: Model Procedures for the Management of Land

Contamination (Ref. 13-2).

13.7.3. Implementation of the proposed approach, described in section 13-6, will

mitigate land contamination risks during construction.

13.7.4. The Envirocheck Report identified moderate ground stability hazards including

compressible ground, and running sands and running sands were identified

during the October/November 2013 GI. Site specific information on ground

conditions for the Proposed Development Site will be considered when the

geotechnical information from the GI is assessed. This is anticipated to take

place following the submission of the DCO Application and will include

recommendations for foundation requirements based on the encountered

ground condition of the Proposed Development Site.

13.7.5. Although not expected, should piled foundations be required in any areas

where contamination is identified (such as due to fly tipping onsite), the piling

design will be subject to a Piling Risk Assessment following EA guidance (Ref.

13-15) post consent, and subsequent regulatory review and agreement.

13.7.6. Ground gas identified a very low risk to the Proposed Development Site.. In

addition, there is little potential for offsite migration onto the land through which


May 2014 Page 13-39

the associated infrastructure is being routed, as this infrastructure does not

include enclosed building spaces, and therefore the effect is considered

negligible.

13.7.7. In summary, no significant effects on land quality are expected to occur

throughout the construction and operational phases, provided that standard

mitigation measures are applied as discussed above. Table 13-11 summarises

the residual effects on land quality and the hydrogeological regime.

Table 13-11: Summary of Residual Effects (post-mitigation)

Description Geographic Scale

Effect Significance

Reversible/Permanent

Construction Phase

Changes to concentrations and extent of soil and groundwater contamination

Local Negligible or Minor Beneficial

Permanent, provided remedial works are

designed appropriately.


- Negligible -

Asbestos - Negligible -

Disturbance of Dust and Silt - Negligible -

Geotechnical Considerations - Negligible -

Ground Gas Local Negligible Permanent, whilst buildings remain on

site.

Underground Structures - Negligible -

Unexploded Ordnance - Negligible -

Operational Phase


District level Minor Adverse Reversible through early detection and

remediation

Use of the cooling water pipeline - Negligible -

Decommissioning Phase

Release of potentially contaminating materials during dismantling of plant

- Negligible

Degradation of soil and groundwater conditions

- Negligible



infrastructure in combination with the potential effects of other developments

proposed for the local area. Consented and proposed schemes within the


May 2014 Page 13-40

area, which are considered sufficiently close to result in potential cumulative

effects with the Proposed Development, have been identified as outlined in

Chapter 7: Assessment Methodology. Identified schemes have been reviewed

in terms of both the construction and operational phase effects.

Construction Impacts

13.8.2. Table 13-12 details potential cumulative effects during the construction phase

of consented and proposed schemes in the local area which are sufficiently

close to either the Proposed Development Site or the proposed cooling water

pipeline corridor.

Table 13-12: Construction Phase Cumulative Issues

Cumulative Development (Applicant)

Potential issues to be considered

Avon Power Station (Scottish Power Generation Ltd)*

The Preliminary Environmental Assessment (Ref. 13-16) identified remediation work in 2010 which removed soils with elevated radiation levels. There is, however, likely to be affected soil remaining at the adjacent Avon Power Station site which may be disturbed during the construction phase. In addition, potential piling works would have the potential to create contamination pathways to groundwater and bring affected soil to the surface as arisings.

Re-Alignment of Approved Spine Road Access (Severnside Developments Land Ltd)

There is the potential for the construction works to disturb contaminated soil in the previously developed section of the site, in the vicinity of the former rail track. (Ref. 13-17)

Central Park (Severnside Distribution Land Ltd)

The land for Central Park is currently being raised to protect against flood risk and although there is a potential for impacted material to be imported to site it is considered that this would be controlled by the developer in liaison with SGC.

Bottom Ash Recovery Facility (SITA UK Limited)

During the construction phase, contaminated soils associated with previous land use as a gas storage facility and rail sidings of the former Severnside Works could be disturbed. Also, the construction of the rhine crossings and potential spillages and site run off could affect surface water quality. In addition piling works have the potential to create contamination pathways to groundwater and bring effected soil to the surface as arisings (Ref. 13-18).

W4B, Former Columbian Chemicals (Sevalco), Severn Road

Redevelopment of part of existing industrial site for a Bio-fuel, renewable energy plant together with ancillary access roads, parking facilities and landscaping. There is the potential for the construction works to disturb contaminated soil in the previously developed section of the site.

Sita/Cyclamax, Plot M2, Merebank Estate, Kingsweston Lane

The Bristol Resource Recovery Centre, currently under construction has the potential to disturb contaminated soil during construction and to release dust to air during the operational phase, although the latter should be controlled by the site’s environmental permit.


May 2014 Page 13-41

Cumulative Development (Applicant)

Potential issues to be considered

Asda/Walmart, Former Rhodia Works, St. Andrews Road

During the redevelopment of the former chemical works, there is the potential for the construction works to disturb contaminated soil.

Biomass Plant (Helius Energy)

The biomass plant ES (Ref. 13-18) identified potential disturbance of the following hazards during the construction phase: contaminated Made Ground from historic coal storage and former railway and fuel storage use as well as unexploded ordnance.

Rockingham Park (Terramond Ltd)

The Design and Access Statement for this development (Ref. 13-19) discusses the heavy antiaircraft battery at Rockingham farm which was built to protect the strategically important docks at Avonmouth and the potential for Made Ground. It is therefore possible that unexploded ordnance and contaminated soils could be disturbed during the construction phase

Resource Recovery Centre (Viridor)

The ES Identified the following potential risks during the construction phase to groundwater quality;

• Accidental spillage of fuels and lubricants required over the short term by construction plant,

• Increase in suspended solids resulting from proposed earthworks,

• Contaminated site run off; and

• Washout of pollutants by water used to extinguish a fire onsite during the operational phase.

Anaerobic Digestion Facility (New Earth)

It is understood to be located on former agricultural land (Ref. 13-20) and as such the potential for the disturbance of contamination would be minimal. During the construction phase however, there is the potential for accidental spills and an increase in suspended solids effecting water resources.

*Pre-application

13.8.3. As outlined above, it is considered that the residual effect of the Proposed

Development on ground conditions will be negligible provided that standard,

current guidelines are adopted in design and that appropriate mitigation

measures are applied (or minor beneficial if remediation occurs). Any adverse

cumulative effect therefore will be due to the effect of these other schemes,

rather than in combination with the Proposed Development. It is also assumed

that the cumulative schemes will all undertake suitable investigation and

assessment of ground conditions and apply appropriate control measures

during construction and operation, such that any mitigation deemed to be

necessary would be completed in line with available regulatory guidance in

order to maintain a negligible cumulative effect.

Operational Impacts

13.8.4. No cumulative effects are assessed for ground conditions during the

operational phase as all developments are expected to have addressed any


May 2014 Page 13-42

contamination or geotechnical issues during the construction phase. It is

anticipated that the cumulative operational effects will therefore be negligible.


13.9.1. At the time of writing the soil and groundwater chemical results and

groundwater level monitoring from the site investigation were not available.

Following receipt of this information the final ES will be updated to include the

analytical findings and a description of the suitability of the DCO Site for the

Proposed Development and associated infrastructure.

13.9.2. In addition, to date, no soil and groundwater data is available for the pipeline

corridor. This will be required prior to construction to allow assessment of the

risks to the identified receptors, but it is not considered that this is required for

the final ES.

13.9.3. The required foundation design solution(s) for the Proposed Development Site

area has not yet been confirmed. Geo-environmental site investigation of the

construction footprint areas is being undertaken in order to establish the most

appropriate foundation design solution(s). It is noted that at the time of writing,

the data from this investigation is not yet available but will be included in the

final ES.

13.9.4. No controlled water risk assessments have been carried out for this PEI Report

as, at the time of writing, the results of the ground investigation, including

chemical analyses, were not available. This data and the need for a controlled

water risk assessment will be presented in the final ES.

13.10. References

Ref. 13-1. Landmark Envirocheck Report, 2013, Ref 50541985_1_1. October 2013.

Ref. 13-2. DEFRA (2004); Model Procedures for the Management of Land Contamination (CLR11).

Ref. 13-3. EA 2002. Industry in Avonmouth, A Guide to pollution Management. EA 2002.

Ref. 13-4. Keller Limited, 1996, Seabank Power Station, Avonmouth Site Remediation Works Completion Report, December 1996, 01.6417/COMREP. Including appended contamination report by PB Power September 2009.

Ref. 13-5. McGill Archaeological Consultants, 2001, Pucklechurch to Seabank Pipeline- Archaeological Programme, October 2001.

Ref. 13-6. British Geological Survey Website www.bgs.ac.uk

Ref. 13-7. EA What’s in my Backyard (http://maps.environment-agency.gov.uk/wiyby/wiybyController?latest=true&topic=pollution&ep=query&lang=_e&x=352608.4791666669&y=179098.08333


May 2014 Page 13-43

33331&scale=11&layerGroups=1&queryWindowWidth=25&queryWindowHeight=25)

Ref. 13-8. Terradat. Geophysical Survey Report: UXO Scanning. Ref 3989. July 2013.

Ref. 13-9. C J Associates Geotechnical Limited. 2006. Crooks Marsh. Report T0925. December 2006.

Ref. 13-10. Building Research Establishment (BRE211), 2007, RADON. Guidance on protective measures for new buildings. 2007.

Ref. 13-11. NHBC/EA, 2008, Guidance for the Safe Development of Housing on Land Affected by Contamination. R&D Publication, 2008.

Ref. 13-12. EA ‘Framework for the Classification of Contaminated Soils in Hazardous Wastes’, version 1

Ref. 13-13. EA, 2005, Guidelines on sampling and testing of wastes to meet landfill waste acceptance procedures’ version 1.

Ref. 13-14. EA, 2001, Piling and Penetrative Ground Improvement Methods on Land Affected by Contamination: Guidance on Pollution Prevention. 2001.

Ref. 13-15. Seabank Power Limited Production. Bulk Storage of Chemicals Spreadsheet. 2009.

Ref. 13-16. Mott MacDonald, 2011, Avon Power Station: Preliminary Environmental Information Report, June 2011.

Ref. 13-17. SLR, 2009. Environmental Statement: Severn Road Resource Recovery Centre. September 2009.

Ref. 13-18. Helius Energy, 2009, Environmental Statement: Proposed 100 MWe dnc biomass fuelled electricity generating station, Avonmouth. February 2009.

Ref. 13-19. Angus Meek Architects, 2011, DP01 Design and Access Statement. 2038 Rockingham Park, Smoke Lane, Bristol. December 2011.

Ref. 13-20. New Earth Solutions Group, 2012, Proposed Anaerobic Digestion Facility at Willow Farm, Severn Road, nr Hallen. 2012

Seabank 3

PEI Report – Chapter 14 Flood Risk, Hydrology and Water Resources

May 2014 Page 14-1

14 Flood Risk, Hydrology and Water Resources

14.1. Introduction

14.1.1. This chapter of the PEI Report assesses the potential effects of the Proposed

Development on flood risk, hydrology and water resources within the vicinity of

the DCO Site.

14.1.2. The potential surface water and groundwater receptors have been identified, with

consideration given to the potential effects during the construction (including

enabling works), operation, and decommissioning phases of the Proposed

Development and associated infrastructure. Incorporated design mitigation,

together with the need for site specific mitigation measures to protect the water

environment have been addressed, along with the nature of residual effects

remaining after mitigation. The cumulative effect of the Proposed Development

along with other consented schemes has also been considered.

14.1.3. This PEI Report summarises the key elements of the Level 3 (Detailed) Flood

Risk Assessment (FRA), which is presented in Appendix J, Volume II of this PEI

Report. The aim of the detailed FRA is to assess the flood risk posed to the

Proposed Development and the effect of the Proposed Development on third

parties, beyond the DCO Site boundary. Mitigation measures to reduce potential

flood risk effects have also been identified. Residual risks are explained and

management measures have been outlined.

14.1.4. The realignment of the Red Rhine (around the northern boundary of the

Proposed Development Site) is being delivered by a third party, Severnside

Distribution Land Ltd under extant planning permission and has been consented

by the Lower Severn Internal Drainage Board (LSIDB). The new Red Rhine

channel will be constructed prior to commencing enabling works onsite (at the

time of writing work had already commenced) and will be considered as part of

the ‘future baseline’ situation onsite. The diversion of flow from the existing Red

Rhine channel into the diversion channel will however form part of the enabling

works for the Proposed Development.

14.1.5. The infilling of the existing Red Rhine channel forms part of the DCO Application,

as does the diversion of a small tributary that currently flows into the Red Rhine

in a northerly direction from land owned by third party to the south of the CCR

Site, known as Crook’s Marsh (hereafter referred to as the ‘Crook’s Marsh

Stream’).

14.1.6. As part of the associated infrastructure, an underground pipeline is proposed to

supply cooling water to/from the Bristol WWTW and the Proposed Development.

The new water pipeline will be approximately 800mm in diameter, located within

a 30m wide corridor adjacent to the existing pipelines which are used to

supply/return cooling water to Seabank 1 & 2.

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May 2014 Page 14-2

Consultation

14.1.7. Consultation with the EA, SGC, BCC, Bristol Water, the LSIDB and Wessex

Water has been undertaken to inform the preparation of this PEI Report.

14.1.8. A Scoping Report (Ref. 14-1) was submitted to the Planning Inspectorate in

February 2013 to allow stakeholders the opportunity to comment on the proposed

structure, EIA methodology and content of this chapter and FRA.

14.1.9. The Planning Inspectorate issued a formal Scoping Opinion (Ref. 14-2) in March

2013. The EA, SGC, and the Marine Management Organisation (MMO) provided

specific guidance for the preparation of this chapter. No comments relevant to

this chapter were received from BCC.

14.1.10. A summary of stakeholder Scoping Opinion comments and how they have been

incorporated into this PEI Report chapter are provided in Table 14-1.

Table 14-1: Relevant Scoping Opinion Responses (issued by the Planning Inspectorate)


Planning

Inspectorate

The assessment should include an

assessment of impacts on water quality.

See section 14.5 and the Level 3 FRA

provided in Appendix J, Volume II.

The FRA should cover tidal flood risk as

well as fluvial impacts and therefore

should consider the potential for

breaching/overtopping of the flood

defence under present and projected sea

level scenarios.

See section 14.5 and the Level 3 FRA

provided in Appendix J, Volume II.

The ES should assess potential impacts

should the diversion of the Red Rhine not

go ahead, or its delivery is otherwise

delayed.

The Proposed Development could and

would not be built prior to the diversion

of the Red Rhine.

EA It may be appropriate to carry out detailed

site specific tidal modelling (breach and

overtopping) to ensure the Proposed

Development is protected over its

development lifetime.

The Level 3 FRA summarised in this

chapter and provided in Appendix J,

Volume II reports on the site specific

tidal modelling (including breach and

overtopping assessment).

SGC The scope of this ES Chapter is generally

appropriate but the chapter should

consider the Avonmouth Severnside

Level 2 Strategic Flood Risk Assessment.

The Local Planning Policy is

summarised in Appendix J, Volume II of

this PEI Report and includes a brief

summary of the SFRA. The site specific

modelling undertaken for the Level 3

FRA provides further detail to the

strategic modelling undertaken as part

of the SFRA.

Seabank 3


May 2014 Page 14-3


MMO The MMO acknowledges that the option

of direct cooling using water from the

estuary has been discarded due to a

combination of technical and

environmental challenges. However, if

direct cooling is selected as the preferred

option a number of marine environmental

impacts will need to be considered.

The direct cooling option has not been

selected therefore this chapter does not

include an assessment of marine

environmental impacts.

Data Sources

14.1.11. Baseline data on water resources and flood risk in the vicinity of the Proposed

Development have been collated by reference to the following sources:

• Environment Agency Groundwater Vulnerability Map of the Southern

Cotswolds (Sheet 37), 1:100,000 Scale (Ref. 14-3);

• Ordnance Survey (OS) Landranger Map, Bristol and Bath (Sheet 172),

1:50,000 Scale (Ref. 14-4);

• Avonmouth / Severnside Level 2 Strategic Flood Risk Assessment (March

2011). Prepared for Bristol City Council, South Gloucestershire, Lower

Severn Internal Drainage Board (Ref. 14-5);

• Severn Tidal Tributaries Catchment Flood Management Plan (December

2009). Prepared by the Environment Agency (Ref. 14.6);

• Landmark Envirocheck Report (September 2012) (Ref. 14-7). Information

on groundwater vulnerability, sensitive land uses, and surface water and

groundwater abstractions;

• Water Framework Directive (WFD) – River Basin Management Plans

(RBMP) – Rivers and Groundwater (Ref. 14-8). Information on water

quality data;

• Groundwater Aquifer Designation Map (Ref. 14-9). Information on

superficial drift and bedrock geology;

• Groundwater Source Protection Zone Map. Information on groundwater

protection zones in relation to public water supply (Ref. 14-10);

• Environment Agency Flood Map (Ref. 14-11). Information on Flood Zone

2 and 3 extents;

• Environment Agency Map of Flood Risk from Reservoirs (Ref. 14-12).

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May 2014 Page 14-4

14.1.12. In addition, specifically commissioned reports and investigations undertaken for

the DCO Site include:

• URS (2014) Seabank 3 CCGT Plant Level 3 Flood Risk Assessment;

• URS (2014) Seabank 3 CCGT Plant Hydraulic Modelling Report. Provides

details of hydraulic modelling undertaken to inform the Seabank 3 site

(provided in Annex J1 of the Level 3 FRA).


14.1.13. The legislation, planning policy and regulations specific to this chapter are

provided in Appendix D, Volume II of this PEI. Key Directives include:

• Water Framework Directive (WFD) (Directive 2000/60/EC) (Ref. 14-13) -

establishes a framework for a European wide approach to action in the

field of water policy. A water body is assessed for Ecological Status and

Chemical Status as part of the WFD, with the EA classifying water bodies

as either: High, Good, Moderate, Poor or Bad; and

• Groundwater Daughter Directive to WFD (Ref. 14-14) - seeks to establish

specific measures as provided for the WFD in order to prevent and control

groundwater pollution.


Source Pathway Receptor Model

14.2.1. The determination of environmental effects has been undertaken using the

Source-Pathway-Receptor model. This model identifies the potential sources or

‘causes’ of effects, as well as the receptors (water resources) that could

potentially be affected.

14.2.2. However, the presence of a potential source and a potential receptor does not

always infer an effect will be generated, there needs to be a pathway or

‘mechanism’ via which the source can have an effect on the receptor.

14.2.3. The first stage in utilising the Source-Pathway-Receptor model is to identify the

causes or ‘sources’ of potential effects from a development. The sources have

been identified through a review of the details of the Proposed Development,

including its size and nature, potential construction methodologies and

timescales.

14.2.4. The next stage in the assessment is to undertake a baseline review of potential

receptors, that is, the water resources themselves that have the potential to be

affected. The final stage of the assessment is to determine if there is a pathway

or ‘mechanism’ allowing an effect to potentially occur between source and

receptor.

Seabank 3


May 2014 Page 14-5


14.2.5. Once potential effects to water resources are identified, it is necessary to

determine how significant the effects are likely to be, to enable the identification

of potential mitigation measures that can counteract adverse effects. The effect

on the receptors depends largely on the sensitivity of the receptor and the

magnitude of change experienced.

14.2.6. An assessment of the significance of each potential effect was undertaken using

the methodology provided in the Web-based Transport Analysis Guidance

(WebTAG); specifically the Water Environment Sub-Objective WebTAG Unit

3.3.11 (Ref. 14-15). The methodology set out in this WebTAG Unit provides an

appraisal framework for taking the outputs of the EIA process and analysing the

key information of relevance to the water environment.

14.2.7. The guidance provides a method by which the significance of the identified

potential effect can be appraised consistently by decision makers. It is based on

guidance prepared by the EA and builds on the water assessment methodology

in the Design Manual for Roads and Bridges (DMRB) (Ref. 14-16). Although this

method was designed for transport projects, it is applicable to, and widely used

for, other development types.

14.2.8. The methodology provides an assessment of the significance of an effect by

firstly considering how important or how sensitive the receptor is and secondly,

by considering the likely magnitude or extent of the change on the receptor. By

combining these two elements, the magnitude of an effect can be derived. If

significant adverse effects are identified, mitigation measures can be proposed to

offset them.

14.2.9. The sensitivity or importance of each water resource (the receptor) is based on

its considered value, for example as an ecological habitat, a source of drinking

water or a recreational resource, as outlined in Table 14-2.

Table 14-2: Derivation of Importance of Water Resource

Importance Criteria Example

Very High Water resource with an importance and rarity at an international level, with limited potential for substitution.

Principal aquifer providing potable water to a large population.

High Water resource with a high quality and rarity at a national or regional level, and with limited potential for substitution.

Principal aquifer providing potable water to a small population.

Medium Water resource with a high quality and rarity at a local scale; or Water resource with a medium quality and rarity at a regional or national scale.

Secondary aquifer providing potable water to a small population.

Seabank 3


May 2014 Page 14-6

Importance Criteria Example

Low Water resource with a low quality and rarity at a local scale.

A non-main river or stream which is not considered significant ecological habitat.

14.2.10. The magnitude of a potential effect is then established based on the likely degree

of change relative to the nature and extent of the Proposed Development, as

shown in Table 14-3. It is important to consider at this stage that potential effects

can be beneficial as well as adverse. The derivation of magnitude is carried out

independently of the importance of the water resource.

Table 14-3: Derivation of Magnitude of Change

Magnitude of change Criteria Example

High Change results in a shift in a water body’s potential attributes, which is clearly significant.

Pollution / remediation of potable source of abstraction resulting in failure / recovery above drinking water standards.

Medium Results in a change to integrity of attribute or loss of part of attribute, which is considered significant.

Loss / gain in productivity of a fishery.

Contribution / reduction of a significant proportion of the effluent in a receiving river, but insufficient to change its WFD classification.

Low Results in a slight change on a water body’s attribute that is not significant.

Measurable changes in attribute, but of limited size and / or proportion.

Neutral Results in an imperceptible change to an attribute that does not affect its use / integrity.

Physical change to a water resource, but no significant reduction / increase in quality, productivity or biodiversity.

No significant change to the economic value of the feature.

14.2.11. Once the magnitude of change is understood, the significance of the potential

impact can then be derived by combining the assessments of both the

importance of the water resource and the magnitude of the change in a simple

matrix, as shown in Table 14-4.

14.2.12. The methodology adopted for this chapter considers major or moderate effects to

be significant, and minor or negligible effects not to be significant.

Table 14-4: Derivation of Effect Significance

Magnitude of Change

Importance of Water Resource (receptor)

Very High High Medium Low

High Major Major Moderate Moderate

Medium Major Moderate Moderate Minor

Seabank 3


May 2014 Page 14-7

Magnitude of Change

Importance of Water Resource (receptor)



Neutral Minor Negligible Negligible Negligible

Flood Risk Methodology

14.2.13. The specific methodology for defining and assessing flood risk is dictated by the

requirements of the NPPF (Ref. 14-17). Planning Practice Guidance released in

March 2014 (Ref. 14-18) provides additional advice to local planning authorities

to ensure the effective implementation of planning policy on development in

areas at risk of flooding. The full details of this methodology for assessing flood

risk are outlined in the Level 3 FRA document included within Appendix J,


14.2.14. For the purpose of this chapter the flood risk to identified receptors is considered

in the context of existing site conditions, the construction phase (including

enabling works) and once the Proposed Development is operational.

14.2.15. In the context of Table 14-2 the importance of the Proposed Development is

classified as ‘high’ based on the reasoning that the development is critical

infrastructure of national importance with limited potential for substitution. The

neighbouring property and land is also used for industrial development of national

or regional importance and is therefore classified as ‘high’ importance.

Water Framework Directive Assessment

14.2.16. A further assessment step has been taken to determine whether an effect is likely

to result in a deterioration of a water body from its current status, or prevent a

water body from achieving ‘Good Status’ (or potential) in the future.

14.2.17. If either of these effects are predicted to occur, this is deemed to be a major

adverse effect to acknowledge that, under the WFD all water bodies must meet

the objectives irrespective of its current status (and hence perceived ‘importance’

in an EIA context).




EIA Process.


under the Rochdale Envelope principle is an important consideration for this PEI

Report, although do not significantly affect the input parameters utilised in either

the operational or construction water resources or water quality assessments.

Seabank 3


May 2014 Page 14-8

14.2.20. The FRA (and information from it that will be included in the final ES) has been

based on the worst-case footprints and heights. This will result in a predicted

maximum volume of water attenuation to maintain greenfield runoff rates from the

Site; this can be reduced if the detailed design post-consent reduces the area of

permeability.


Introduction

14.3.1. This section summarises information on the baseline conditions of surface water

and groundwater receptors that have the potential to be influenced by the

Proposed Development. Potential water resource receptors have been

considered using data sources detailed in Section 14.1.

14.3.2. Particular attention is given to identifying any notably sensitive water bodies with

specific environmental targets or specific resource uses. A summary of baseline

flood risk information from the Level 3 FRA (Appendix J, Volume II of this PEI

Report) is also presented below.

Surface Water Receptors

14.3.3. Figure 14-1 (Volume III of this PEI Report) shows the location of watercourse

features and catchment areas in the vicinity of the DCO Site, which are described

below.

Hydrology

14.3.4. The Red Rhine flows directly through the Proposed Development Site in an east

to west direction towards the Severn Estuary. The Red Rhine is currently a

relatively small man-made drainage channel, embanked on both sides. Along the

majority of its length the Red Rhine comprises a 3m base, in an approximately

1.5m deep channel, with a top width of between 8m and 11m.

14.3.5. The Red Rhine catchment is a flat low lying catchment with a total catchment

area of 6.7 square kilometres (km2). The Red Rhine is fluvially dominated and

discharges into the tidal River Severn at New Pill Gout, approximately 600m

downstream of the Proposed Development Site. Prior to discharge to the tidal

River Severn, the Red Rhine enters a culvert through the (A403) road

embankment, a sluice gate (located between the road embankment and railway

embankment) and a large underpass beneath the railway embankment.

14.3.6. The Red Rhine catchment includes the existing Seabank 1 & 2 generating station

and a number of other consented schemes (see Section 14.7). West of the

Proposed Development Site, a third party has begun construction of the

consented Severnside Energy Recovery Centre, and to the north there is

cleared, hardstanding land where Terra Nitrogen and ICI used to operate. The

Seabank 3


May 2014 Page 14-9

Avonmouth LNG Storage Facility is located upstream (to the southeast) of the

Proposed Development Site. The M49 crosses the catchment area from north to

south, approximately 1.5km east of the Proposed Development Site. The

northern edge of Hallen is also located within the southern extent of the Red

Rhine catchment.

14.3.7. A number of smaller tributaries flows into the Red Rhine and criss-cross the

Proposed Development Site currently. These will need to be realigned to drain

into the new Red Rhine channel. The most important of these tributaries is

Crook’s Marsh Stream’ that flows from the south of the CCR Site, joining the Red

Rhine near the northeast corner of the CCR Site.

14.3.8. The Stuppill Rhine is located approximately 1km to the south of the Proposed

Development Site and crosses the DCO Site approximately half way along the

length of the proposed cooling water pipeline corridor. The catchment for this

rhine is flat and low lying (similar to the Red Rhine catchment) and drains a total

area of 2.2km2. The Stuppill Rhine is not hydrologically linked to the Red Rhine,

as both discharge directly into the tidal River Severn and therefore, no impact on

the Stuppill Rhine is anticipated during the construction or operation phase of the

main Proposed Development. However, the Stuppill Rhine is the most significant

watercourse traversed by the proposed cooling water pipeline corridor and

requires consideration as part of this assessment.

14.3.9. The Redwick Common Rhine is located approximately 2km to the north of the

Proposed Development Site. This flat, low lying catchment drains a total area of

8.1km2. A number of other minor rhines are present within this catchment area.

The land-use within this catchment is less industrial than the Red Rhine and

Stuppill Rhine catchments and includes residential areas of Easter Compton and

Severn Beach. The Redwick Common Rhine is not hydrologically linked to the

Red Rhine, as both discharge directly into the tidal River Severn. The Redwick

Common Rhine does not cross the DCO Site and therefore, no impact on the

Redwick Common Rhine is anticipated during the construction or operation

phase of the Proposed Development.

Site Drainage

14.3.10. The Proposed Development Site is predominantly flat and low-lying and poorly

drained with frequent areas of standing surface water and marshland. A review of

OS mapping (Ref. 14-4) indicates that the southern end of the Site is an area

known as Crook’s Marsh.

14.3.11. The Proposed Development Site is dissected by several minor drainage channels

and a major channel (the Red Rhine) running in a north-west direction through

the centre of the site.

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May 2014 Page 14-10

14.3.12. Prior to commencing enabling works for the Proposed Development the new Red

Rhine channel is anticipated to have already been cut around the northern

boundary of the Proposed Development Site by Severnside Developments Land

Ltd and is therefore considered as part of the ‘future baseline’; this work is

currently underway at the time of writing and is expected to be completed by the

first quarter of 2015.

14.3.13. The diversion of flow from the existing channel into the new diversion channel will

form part of the enabling works, as will the infilling of the existing channel.

14.3.14. The diversion of the Crook’s Marsh Stream (tributary of the Red Rhine) (see

Figure 14-1, Volume III of this PEI Report) also forms part of the DCO

Application. The Crook’s Marsh Stream will be diverted across the eastern corner

of the CCR Site to the diverted Red Rhine.

Coastal Waters

14.3.15. The Red Rhine discharges to the tidal River Severn approximately 600m

downstream of the Proposed Development Site. The tidal River Severn is

therefore the ultimate downstream surface water receptor from the Proposed

Development Site.

14.3.16. As identified on Figure 14-1 (Volume III of this PEI Report), this part of the River

Severn is statutory designated as a SSSI and internationally recognised as a

SAC, SPA and Ramsar site. It is also internationally recognised as an Important

Bird Area (IBA).

Surface Water Quality and Ecological Status

14.3.17. The EA measures water quality of inland surface waters (rivers and lakes),

transitional waters (estuaries), coastal waters and groundwater with reference to

standards set by the WFD.

14.3.18. The WFD seeks to ensure all controlled water bodies achieve 'good status /

potential' by 2015 (or 2027 if extensions are permitted). This overall status takes

into account the biological, chemical, hydro-morphological and specific pollutants

quality of the water body.

14.3.19. As part of the EIA, water quality data has been requested from the EA.

Unfortunately the spatial and temporal data coverage for this area is limited.

However, the EA has provided interim WFD classification results for the Redwick

Common Rhine (from source to confluence with the Pill) for 2012.

14.3.20. This data indicates that the Redwick Common Rhine is classified as having an

overall ‘poor’ current ecological potential, based on a poor biological and a ‘not

high’ hydromorphological quality. The Redwick Common Rhine is classified as a

highly modified water body, designated due to being an artificial drainage

Seabank 3


May 2014 Page 14-11

channel. The WFD objective for Redwick Common Rhine is to achieve ‘good’

ecological potential by 2027.

14.3.21. From observations made during the site walkover and a review of geological and

OS mapping, the Red Rhine and Stuppill Rhine are considered to share similar

catchment characteristics to the Redwick Common Rhine, in terms of land-use,

typology and hydro-morphological status (i.e. artificial drainage channels).

14.3.22. Therefore, in the absence of WFD classification data for the Red Rhine and

Stuppill Rhine it is considered reasonable to assume that the Red Rhine and

Stuppill Rhine can also be classified as having an overall ‘poor’ current ecological

potential WFD classification, similar to the Redwick Common Rhine.

Surface Water Abstractions and Discharges

14.3.23. The locations of water abstraction and discharge consents held within the vicinity

of the Proposed Development Site are shown in Figure 14-1(Volume III of this

PEI Report).

14.3.24. The Envirocheck Report (Ref. 14-6) for the Proposed Development Site and

surrounding area indicates that no abstraction licences and nine discharge

consents licences are held within the Red Rhine catchment area. Discharge

consents located closest to the Proposed Development Site (approximately 500m

from the Site boundary) are operated by Wessex Water. These allow discharge

of treated sewage effluent and storm water overflow to tributaries of the Red

Rhine.

14.3.25. No abstraction licences exist within 200m of the proposed cooling water pipeline

corridor. There are 18 discharge consents located within (or bordering) the

Stuppill Rhine catchment, with a number of these located in close proximity to the

proposed cooling water pipeline corridor.

14.3.26. These discharge types are for surface water and trade effluent discharges from

local industry, or sewage discharges from the Bristol WWTW. All licences allow

discharge to surface waters along the local rhine network.

14.3.27. SGC and BCC have confirmed that no properties within the vicinity of the DCO

Site are listed on their private water supply registers.

Groundwater Receptors

14.3.28. Geology, hydrogeology and land contamination is considered in detail in Chapter

13: Ground Conditions. However, a review of available geology and

hydrogeology data has also been undertaken to inform this chapter of the PEI

Report.

14.3.29. A summary is provided in the following sections.

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May 2014 Page 14-12

Geology

14.3.30. Superficial deposits underlying the DCO Site are Quaternary age Tidal Flat

deposits consisting of normally consolidated soft silty clay, with layers of sand,

gravel and peat. The bedrock comprises Triassic age Mercia Mudstone Group

described as dominantly red, less commonly green-grey, mudstones and

subordinate siltstones.

14.3.31. Table 14-5 presents a summary of the geological strata encountered during the

2013 ground investigation based on the draft logs available at the time of writing

(BH001, BH003, BH004, BH005 and BH006).

Table 14-5: Summary of Site Geological Strata

Strata Depth Range (m bgl) Description

Reworked Natural Ground

0 – 0.30 Firm dark brown slightly sandy clay with frequent rootlets. (Identified in BH004 only)

Tidal Flat Deposits 0.20 – 14.00

Firm, locally soft, fissured brown mottled grey silty Clay. Occasional fragments of partially decomposed plant material and occasional PEAT.

Weathered Mercia Mudstone Group

9.00 – 17.50 Very stiff fissured dark reddish brown grey silty clay.

Mercia Mudstone Group

11.95 – base not proven Extremely weak dark reddish brown mudstone interbedded with extremely weak to weak light greenish grey sanstone.

m bgl: metres below ground level

Hydrogeology

14.3.32. The EA Groundwater Aquifer Designation Map (Ref. 14-9) indicates that the

bedrock underlying the DCO Site, which includes the proposed cooling water

pipeline corridor, is classified as a Secondary B Aquifer; predominantly lower

permeability layers which store and yield limited amounts of groundwater due to

localised features such as fissures, thin permeable horizons and weathering.

Generally the water-bearing parts are of the former non-aquifers. The superficial

deposits on the site are classified as unproductive strata.

14.3.33. The EA Groundwater Vulnerability Map (Ref. 14-3) indicates that the underlying

geology beneath the entire DCO Site (including the water supply pipeline route)

is Non-Aquifer of negligible permeability and located outside of a Groundwater

Source Protection Zone.

Groundwater Quality

14.3.34. The EA WFD River Basin Management Plan (Ref. 14-8) indicates that the

groundwater quality (quantitative) underlying the DCO Site and surrounding area

is classified as ‘good’ and is predicted to remain ‘good’ for the foreseeable future.

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Similarly, the current chemical quality is ‘good’ and is also predicted to remain

‘good’ in 2015.

Water Supply and Sewage Infrastructure

14.3.35. Bristol Water is responsible for water supply within the vicinity of the DCO Site.

Liaison with Bristol Water has confirmed that a 24” (610mm) diameter trunk main

is located within the Proposed Development Site boundary, as shown in Figure 3-

1 in Volume III of this PEI Report. This mains water pipe used to supply water to

the former Terra Nitrogen and ICI site immediately north of the Proposed

Development Site and an off-take from this pipeline currently supplies the

Seabank 1 & 2 generating station.

14.3.36. Wessex Water is responsible for the sewage infrastructure within the DCO Site

and has confirmed that no sewage infrastructure exists within the vicinity of the

DCO Site. However, two 540mm and 560mm underground pipelines are known

to supply and return cooling water from the Bristol WWTW to/from the Seabank 1

& 2 station.

Flood Risk

14.3.37. The Level 3 FRA (see Appendix J, Volume II of this PEI Report)) indicates that

the entire DCO Site is located within Flood Zone 3a and that the Proposed

Development is classified as ‘Essential Infrastructure’. This type of development

is only permitted within Flood Zone 3a where it can be demonstrated that the

Exception Test has been passed.

14.3.38. To satisfy the requirements of the Exception Test the Level 3 FRA assesses the

risk posed to the Proposed Development and its impact on third party property. A

hydraulic model has been developed to further understand fluvial and tidal flood

risk associated with the Proposed Development Site, as shown in Annex J1 of

the FRA. It has not been necessary to model the proposed electrical cable route

or cooling water pipeline, the latter of which will be buried underground and the

former will be either underground or routed to the substation on a cable rack

inside a waterproof casing to protect against water damage through Seabank 1 &

2.

14.3.39. The model results have been used to inform suitable design mitigation measures

(see Section 14.5) to ensure that the Proposed Development and site users

remain safe over the development lifetime and ensure flood risk to third parties is

not increased. These measures are intended to ensure that the requirements of

the Exception Test are passed.

14.3.40. The following paragraphs summarise the existing baseline flood risk conditions,

for all sources of flooding, as identified within the Level 3 FRA.

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Fluvial

14.3.41. The Level 3 FRA flood mapping outputs indicate that during the ‘existing

baseline’ scenario, flooding occurs in areas of the Proposed Development Site

during all fluvial events considered. During the 1 in 100 year (inclusive of climate

change) a peak flood depth of 0.52m is apparent along the lower lying southern

perimeter of the Proposed Development Site. The risk posed by fluvial flooding to

the Proposed Development and wider Proposed Development Site is therefore

considered high.

Tidal

14.3.42. The Level 3 FRA flood mapping outputs indicate that during the 1 in 200 year

(inclusive of climate change) tidal event combined with the 1 in 100 year fluvial

event (inclusive of climate change) the DCO Site is inundated with floodwaters.

However, the increase in flood depth is minimal (0.01m) when compared to the

equivalent fluvial only event where no extreme tidal component is considered.

14.3.43. Therefore, the actual risk posed to the Proposed Development Site and wider

DCO Site by tidal flooding is considered low. However, a residual risk due to

potential tidal defence breach still remains. This is discussed further in the

impacts and mitigation section (Section 14.5).

Other Flood Sources

14.3.44. The risk of flooding from other sources, such as surface water, sewer,

groundwater and artificial sources is deemed to be low or negligible.

Baseline Summary

14.3.45. A summary of surface water and groundwater receptors identified in the baseline

conditions including their allocated importance classification (based on the

criteria shown in Table 14-2) is provided in Table 14-6. Table 14-6 also indicates

whether the surface or groundwater receptor is considered further in the

assessment (based on a review of baseline conditions) and provides justification

for the decision made.

14.3.46. A summary of the risk posed by all flood sources, including an indication of

whether they are considered further within this PEI Report is provided in Table

14-7.

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Table 14-6: Summary of Surface and Groundwater Receptors

Receptor Importance / sensitivity

Considered Further in Assessment

The Red Rhine (including Crook’s Marsh Stream)

High Yes – flows and water quality potential affected by the Proposed Development

The Stuppill Rhine (and minor tributaries)

High Yes – Stuppill Rhine represents the most significant watercourse traversed by the proposed cooling water pipeline corridor

The Redwick Common Rhine (and minor tributaries)

High No – Not hydrologically linked, therefore no impact to watercourse anticipated

Tidal River Severn Very High Yes – Ultimate downstream receptor

Shallow Groundwater High Yes –Shallow groundwater encountered at the DCO Site and is considered to be hydrologically linked to surface waters

Deeper Groundwater High Yes – Shallow and deeper groundwater at the DCO Site are considered to be hydrologically linked

Table 14-7: Summary of Risk Posed by all Flood Sources

Flood Source Level of Risk

Considered Further in Assessment

Fluvial High Yes – Design mitigation required to reduce risk posed to the Proposed Development to an acceptable level

Tidal (Actual) Low Yes – Mitigation proposed for fluvial and residual tidal risk will further reduce actual tidal risk

Tidal (Residual) High Yes – Design mitigation required to manage residual risk in the event of a failure or breach in the flood defences

Surface Water / Sewer Low Yes – Design mitigation required to manage surface water runoff from the Proposed Development using SuDS measures

Groundwater Low No – Not considered to pose a significant risk to the Proposed Development

Artificial Sources Negligible No – Not considered to pose a significant risk to the Proposed Development


14.4.1. A number of avoidance measures that are being implemented in the design of

the Proposed Development are relevant to flood and hydrology.

14.4.2. In particular, hydraulic modelling demonstrated a need to achieve a minimum

finished floor level of 8.31m AOD to protect against flood risk, which has been

increased to a commitment to raise the Generating Station Site to up to 8.5m

AOD to reduce the level of precision required by a Contractor.

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14.4.3. In addition, land has been allocated for a surface water attenuation pond of

capacity equal to the maximum required, based on the calculations in the FRA.


14.5.1. The Proposed Development and associated infrastructure have the potential to

affect water resources features within the area. Effects arising as a result of the

development, both beneficial and adverse, could affect the Proposed

Development’s ability to satisfy the criteria outlined within the relevant local,

national and European planning policy and legislation.

14.5.2. The significance of any effect depends on the sensitivity of the water resources

and the current conditions of such resources, the magnitude of any change and

the implementation of any mitigation measures during construction and

operation.

14.5.3. The following section takes into account both design mitigation incorporated into

the Proposed Development and additional measures such as management

controls or physical measures to further manage identified effects deemed to be

significant.

14.5.4. The significance of effects pre-mitigation is not provided in this section, with the

significance identified for residual effects only (see Section 14.6). It has been

assumed that any construction effects (short and medium term) are temporary

and any operational effects (long term) are permanent, unless otherwise stated.

Construction Phase

14.5.5. The enabling works and construction phase of the Proposed Development and

associated infrastructure have the potential to affect both surface water and

groundwater bodies located in the vicinity of the works.

14.5.6. Construction activities which give rise to such effects are described in Chapter 4:

Project Description and Chapter 5: Enabling Works and Construction.

Water Quality

14.5.7. Key activities and their potential effects include:

• Removal of topsoil and excavation required for the proposed cooling

water supply pipeline and raising of the Proposed Development Site

above design flood levels during construction. This will require the

temporary storage of stockpiles of soil and construction materials. Without

adequate mitigation this has the potential to increase the generation of

surface water runoff with elevated concentrations of sediment, which may

have a temporary adverse effect on the water quality of local surface

water receptors;

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• Piled foundations for the larger structures associated with the Proposed

Development is likely to penetrate the water table, which Chapter 13:

Ground Conditions states as being measured as 2.06m bgl and 2.54m

bgl. As a result there is potential for groundwater to seep into such

excavations, and therefore, dewatering may be required to allow

construction to continue. This activity may have a temporary adverse

effect on groundwater and surface water flows paths, and draw in

potentially contaminated water and open pathways between the shallow

and deeper groundwater bodies;

• The transportation, storage and use of oils and fuels for construction plant

and handling of wet cement and/or concrete, will increase the risk of

accidental spillages and contamination of surface waters and/or

groundwater, which has the potential to result in a temporary adverse

effect on local surface and groundwater receptors without adequate

mitigation;

• Provision of onsite sanitary facilities for construction site staff could also

introduce an additional source of pollution, with the potential to cause

nutrient enrichment of receiving water bodies. This activity may have a

temporary adverse effect on surface water receptors; and

• Handling of construction waste materials and wastewater could also

introduce an additional source of pollution to local surface and

groundwater receptors resulting in a temporary adverse effect dependent

on the presence and extent of potential contamination sources.

Water Quantity


• As part of the enabling works the water flow within the existing Red Rhine

channel will be diverted into the new diversion channel that Severnside

Distribution Land Ltd is currently constructing along the northern

perimeter of the Proposed Development Site. The Crook’s Marsh Stream,

a tributary of the Red Rhine, will also need to be diverted to accommodate

the Proposed Development. The proposed route of the water supply

pipeline will transverse the Stuppill Rhine and a number of other minor

drainage channels;

• To undertake these works it may be necessary to temporarily obstruct the

channels and divert the surface water flows around the excavation via use

of a pump system, which could lead to a temporary adverse effect on flow

rate and discharge volumes immediately downstream of works and

cessation of flow across an approximate 10m section of the channel bed;

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• Construction of the proposed cooling water pipeline corridor may require

temporary dewatering of the excavation in some locations where the base

of the trench lies beneath the water table. Dewatering may lead to a

reduction in water levels within the surrounding area and may focus

groundwater flow towards the trench. However, groundwater impacts

related to pipeline installation construction works will be of limited

duration, as the pipeline trench will be backfilled. Therefore there is

anticipated to be very limited impact due to temporary dewatering during

the construction phase. Furthermore no water abstractions are located in

close proximity to the new pipeline route, as indicated in the ‘Baseline

Conditions’ section of this chapter;

• The installation of the proposed cooling water pipeline corridor may

require the obstruction and diversion of minor watercourses, which are

discussed further below.

14.5.9. The electrical connection through the Seabank 1 & 2 site is not expected to have

any adverse effect on surface water of groundwater flow. It will either be above

ground in cable racks or installed beneath the existing Seabank 1 & 2 generating

station using HDD techniques.

Mitigation

General Mitigation Measures

14.5.10. Construction will take place in accordance with all relevant legislation for the

protection of surface and groundwater and codes of best practice guidance for

works on or near water. Several references are pertinent, including the Pollution

Prevention Guidelines prepared by the Environment Agency. The following

Pollution Prevention Guidelines (PPG) are of particular relevance to construction

site activities:

• PPG1: General guide to the prevention of pollution;

• PPG2: Above ground oil storage tanks;

• PPG5: Works in, near or liable to affect watercourses;

• PPG6: Working at demolition and construction sites; and

• PPG21: Pollution incident response planning.

14.5.11. The appointed Contractor will be required to prepare a method statement for

potentially polluting activities during the construction phase, to be included in the

CEMP. The method statement will describe how construction activities shall be

undertaken and managed in accordance with requirements identified within this

PEI Report and the final ES that will accompany the DCO Application.

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14.5.12. Surveillance monitoring of the Red Rhine (and Crook’s Marsh Stream) in the form

of routine visual observations will be undertaken immediately upstream and

downstream of the Proposed Development Site boundary, both prior to

construction (to establish baseline conditions) and then during the construction

phase.

14.5.13. The purpose of the surveillance monitoring will be to identify potential

contamination, such as the presence of oil spills and higher sediment loading,

and to indicate the need for further investigation such as spot monitoring of pH,

conductivity and dissolved oxygen. In the event of any significant deviation from

baseline conditions, samples will be taken for water chemistry laboratory analysis

covering a wide suite of water quality parameters.

Excavations and Land Raising

14.5.14. Bulk materials such as topsoil and excavated/fill material will be stored in

designated areas away from watercourses and, if deemed necessary by the

CEMP, covered to prevent erosion. The 8m maintenance access strip proposed

alongside the realigned Red Rhine is likely to be at a slightly lower ground level

than the Generating Station Site (following land raising, which is discussed

below) and will not be used for material stockpiles adjacent to the Red Rhine.

14.5.15. However, in general a minimum 10m buffer strip will be adopted for material

stockpiles from the Red Rhine to reduce pollution risks, where possible. Specific

guidance in dealing with silt arising from construction activities is contained within

PPG5, which will be taken into account within a CEMP.

14.5.16. As detailed in Chapter 13: Ground Conditions, intrusive investigations have been

undertaken on the Site to determine the presence of potential contaminant

sources. If found to be present, contamination would create potential constraints

to be resolved during the development works, however it is anticipated that these

can be managed through the correct use of the CEMP and CMS.

Channel Diversions and Pipeline Crossings

14.5.17. During the detailed design phase, temporary and permanent works will be

designed so as to minimise disruption to flows and disturbance to the

watercourse’s bed, channel and banks. A method statement for undertaking work

in the vicinity of any watercourse will be prepared by the Contractor and

approved in advance by the supervising engineer (for the Contractor) and where

necessary the LSIDB in order to minimise any potential impact on surface water

quality or flows.

14.5.18. A Flood Defence Consent will be sought from the LSIDB for the crossing of

Stuppill Rhine and other minor drainage channels as required. A method

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statement will also be produced and implemented through the CEMP for the

control of channel flows during this period.

Temporary Site Drainage

14.5.19. A detailed Drainage Management Plan will be produced following receipt of the

DCO to ensure contaminated water is appropriately managed and treated prior to

entering into any water body. A framework strategy for this Plan will be included

as part of the submission of the DCO. For example, where there is a requirement

for disposal of water from excavations (due to dewatering activities), water will be

treated (e.g. ‘on-site settlement tanks) to remove potential contaminants, prior to

being discharged to surface waters.

Storage and Use of Chemicals, Fuel/Oil and Other Construction Material

14.5.20. Construction of concrete structures would be monitored by the contractor as part

of the CEMP so that work is stopped and amended if contaminated material is

found to be entering any watercourses. Pre-cast work will be utilised where

possible to reduce the amount of in-situ concreting required adjacent and above

the watercourses.

14.5.21. Washing out of concrete wagons or other equipment used in concreting

operations is not planned onsite.

14.5.22. The positioning of fuel storage tanks and other potentially polluting materials and

maintenance/refuelling facilities will be within designated bunded areas with drip

trays placed on standing machinery to avoid pollution from spillages and leaks.

The volume of the bunded areas will be at least the capacity of the tank(s) plus

10%.

14.5.23. Spill kits will be made available, and construction site workers trained in their use,

to deal with any spillages. All spill kits will be fully stocked at all times and an

inventory of equipment within the container will be clearly displayed within the lid.

14.5.24. Stores of construction materials will be in bunded or kerbed areas. The drainage

system of the bund will be sealed with no discharge to any water body.

14.5.25. Foul water (consisting of sewage and domestic type waste water) from welfare

facilities on site will be discharged via the foul water connection in Seabank 1 & 2

or treated on site within a packaged sewage treatment plant. The treated effluent

will be discharged to a local sewer in Seabank 1 & 2.

14.5.26. Taking this mitigation into account the residual effect on water quality and water

quantity during operation is negligible to minor adverse, depending on the

sensitivity of the receptor.

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Fluvial/Tidal Flood Risk – Onsite Impacts

14.5.27. Unmitigated, the actual or residual risk posed to the Proposed Development from

fluvial and tidal sources is potentially high. To mitigate this risk, ground raising

across the Generation Station Site (an area of up to 8.5ha) is proposed based on

the findings of the detailed FRA.

14.5.28. The remainder of the Proposed Development Site is made up of the Utilities,

Services and Landscaping Area (6.4ha) which does not require additional flood

risk protection and a further 6.3ha that is reserved for carbon capture equipment

in the event that this is required in the future. In addition, as mentioned

previously, the Other DCO Land that contains the cooling water pipeline and

electrical connection is not vulnerable to flood risk and therefore does not require

mitigation.

14.5.29. The Level 3 FRA ‘future baseline’ scenario incorporates the Red Rhine diversion

and achieving a minimum finished floor level for the Proposed Development of

8.31m AOD, as shown to be required by the hydraulic modelling in Annex J1 of

the FRA (although the DCO Application incorporates the ability to raise the land

up to 8.5m AOD). The 8.31m AOD level represents the minimum finished floor

level for the Proposed Development; however, certain equipment such as the

cooling water system which can be bunded to protect them from flood risk may

not require land raising to this minimum level. For the purpose of this PEI Report

however it is considered a robust assumption and the worst-case scenario in

terms of potential flood water displacement, to assume minimum ground levels

for the Proposed Development will be 8.31m AOD.

14.5.30. The detailed FRA indicates that during the ‘future baseline’ scenario, land raised

within the Proposed Development Site boundary is predicted to remain dry for all

fluvial scenarios, including 1 in 1000 year (inclusive of climate change) event and

all tidal scenarios (including breach events) up to 1 in 200 year (inclusive of

climate change) event.

14.5.31. Depending on the timing of the flood event in relation to the extent of land raising

completed at that time, this mitigation could have a negligible to major

beneficial effect on the flood risk posed to the Proposed Development Site and

construction workers.

14.5.32. To ensure site evacuation occurs prior to the onset of a flood event the

construction site manager will register with the EA Flood Warning Service and

have a flood evacuation plan in place to ensure construction workers are

informed of the potential flood risk and appropriate actions to take during a flood

event (i.e. safe refuge).

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Fluvial/Tidal Flood Risk – Offsite Impacts

14.5.33. The offsite effect to neighbouring property and land resulting from the

displacement of floodwater associated with proposed land raising has been

considered. The floodwater displaced by the Proposed Development represents

only 1.4% of the total volume displaced during the extreme fluvial dominant flood

event and 5.4% during the tidal breach event.

14.5.34. The volume of floodwater displaced by the proposed land raising has been

considered in the FRA. The floodwater displaced by the Proposed Development

during the modelled tidal breach scenario is predicted to raise local flood levels

by 0.003m (3mm), when distributed across the flood cell (which covers an area of

47km2 and extends from Avonmouth in the south to the Severn Road Bridge in

the north.

14.5.35. This increase is considered to have a minor adverse effect on the flood risk

posed to third parties on adjacent land, reducing to negligible with distance from

the Site.

Surface Water Flood Risk

14.5.36. The surface water flood risk posed to the Proposed Development Site is

considered low. Proposed land raising is considered to have a minor beneficial

effect on the surface water flood risk posed to the Proposed Development Site

and construction workers.

14.5.37. Prior to the Site drainage network becoming operational, there is potential for a

temporary increase in rates and volumes of surface water runoff generated

across the Proposed Development Site, due to soil compaction and the gradual

increase in impermeable area.

14.5.38. To mitigate potential adverse effects, where required, temporary SuDS features

(such as swales / ditches) will be used in locations where preferential flow

pathways offsite are identified. These measures will be included in the Drainage

Strategy to accompany the DCO Application and the detailed Drainage

Management Plan, which will be produced following receipt of the DCO. Taking

these mitigation measures into account, the risk posed to third parties will remain

low and the residual effect is anticipated to be minor adverse, albeit temporary

in nature as a drainage strategy will be implemented for the operational

development.

Operational Phase

14.5.39. The potential to affect both surface water and groundwater bodies is significantly

reduced during the operation phase of the Proposed Development. The key

activities and potential effects are identified below.

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Water Quality and Quantity

Water Quality

14.5.40. Key activities and their potential effects prior to mitigation include:

• The increase in built hard surface areas (e.g. concrete) can lead to

flushing effects, whereby site runoff mobilises sediment accumulated over

time. Discharge to adjacent surface waters via drainage system could

potentially lead to sedimentation;

• Routine use / presence of lorries, cars and other vehicles across the site

and on access routes and associated activities such as re-filling distillate

tanks, accidental spillages and minor leaks all have the potential to

contaminate runoff in the locality with hydrocarbons or other chemicals;

• Water from the cooling water system returning to the Bristol WWTW is

expected to be on average 25-26 degrees Celsius (°C) when the

Proposed Development is in operation. Discharge of higher temperatures

of cooling water from the WWTW could have an adverse effect on the

receiving surface water;

• Potential for nutrient enrichment and contamination of water bodies as a

result of inadequate foul water drainage facilities.

14.5.41. Mitigation measures to minimise the risk of the above occurring and the

magnitude of change caused by such events, are outlined later in this chapter.

Water Quantity


• On completion of the Proposed Development, surface water runoff from

the Site will be designed to be restricted to pre-development rates for the

1 in 100 year including climate change rainfall event (76 l/s) using SuDS

techniques in accordance with the Drainage Strategy and Drainage

Management Plan. Taking this into account, the operational phase is

anticipated to have a negligible effect on the hydrology of the local

drainage ditches (i.e. Red Rhine and Crook’s Marsh Stream).

• Cooling water will be supplied to the Proposed Development via the

proposed cooling water pipeline corridor connected to the Bristol WWTW.

The cooling water systems would have an initial demand of approximately

600 m3/hr, after which it becomes a closed system with approximately 1%

lost to evaporation and spillage which needs to be topped up

intermittently. In addition to this, the cooling water system will also be

flushed out and replaced periodically;

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• The cooling water received from the Bristol WWTW will be treated to its

required effluent discharge standards. For use within the generating

station’s process, the cooling water requires additional treatment / dilution

to make it suitable for use, using the Seabank 1 & 2 chemical treatment

plant. It may also require dilution using towns mains (potable) water to

achieve water quality levels required for use in the generating station. The

cooling water supply is therefore considered to have a permanent

beneficial effect on water quality as the water should be returned to the

WWTW cleaner than it was supplied and can subsequently be used to

dilute Wessex Water's discharges into the estuary;

• The installation of the proposed cooling water pipeline corridor is not

anticipated to have a significant effect on shallow groundwater flows when

compared to baseline conditions. A significant amount of the excavation

will be within made ground which is already disturbed from its natural

condition, most likely during the installation of the existing water supply

pipeline for Seabank 1 & 2. The majority of the pipeline is expected to be

above the water table, and providing adequate water stops are included

within saturated sections of the pipeline trench to avoid groundwater

eroding the backfill material and creating new pathways, significant

permanent alteration in the regional groundwater flow regime is not

considered likely to occur. In addition, no water abstractions which could

be adversely affected have been identified in close proximity to the

proposed route of the pipeline.

• The electrical connection through the Seabank 1 & 2 site is not expected

to have any adverse effect on surface water of groundwater flow during

operation as previously discussed.

Mitigation Measures

14.5.43. To minimise the risk of pollution entering controlled waters during the operational

phase the following measures will be implemented:

• Surface water from areas with a low risk of contamination with oils will be

discharged via silt traps to a local surface water body. In areas onsite

where there is an increased risk of runoff containing pollutants such as

oils and hydrocarbons (such as car parking areas), surface water will be

pass through an oil interceptor prior to discharge to a local surface water

body;

• Any operational activities that carry significant risk of oils / hydrocarbon

spillage will comply with EA guidance PPG1 and PPG5 and shall be

incorporated into the management procedures associated with the

operation of the generating station;

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• Foul drainage will be treated at an onsite treatment plant prior to being

discharged to the Bristol WWTW via the cooling water return flow pipe;

• Prior to discharge to estuary via the Bristol WWTW, Wessex Water mix

the cooling water from the water supply pipeline with other effluent from

the WWTW, which should lower the discharge temperature. Effluent

discharge from the Bristol WWTW is controlled by a discharge consent

which requires Wessex Water to achieve a certain discharge temperature;

• Regular pipeline inspection and monitoring will ensure that significant

uncontrolled discharges are detected in a timely fashion. Contingency

plans will be set up to minimise the impact of uncontrolled discharge

resulting from any breach in the pipeline. Should repair work be required

to the water supply pipeline, then the general mitigation measures as

discussed for the construction phase will be implemented to minimise the

impact of the works;

• Surveillance monitoring will be carried out on the Red Rhine onsite once

the Proposed Development is operational as part of the Site’s

environmental duties. Where a visual inspection indicates discolouration

to surface waters, further water quality samples will be taken for water

chemistry laboratory analysis covering a wider suite of water quality

parameters. A record of water quality results would be maintained for EA

review.

14.5.44. Taking this mitigation into account the residual effect on water quality during

operation is anticipated to be negligible to minor adverse, depending on the

receptor; the latter is due to a low magnitude of change on a high importance

receptor, which is shallow groundwater.

Fluvial/Tidal Flood Risk - Onsite

14.5.45. Land within the Proposed Development Site boundary will be raised above

modelled flood levels and include a freeboard allowance to account for potential

uncertainties in model and climate change predictions over the development

design life (i.e. 30 years). This mitigation will have a major beneficial effect on the

risk posed to the Proposed Development Site, by reducing the tidal/fluvial flood

risk to low.

14.5.46. To ensure site evacuation occurs prior to the onset of a flood event during the

operational phase the Site Manager will register with the EA Flood Warning

Service and have a Flood Emergency Plan to ensure site workers are informed of

the potential flood risk and appropriate actions to take during a flood event (i.e.

safe refuge).

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14.5.47. To ensure that evacuation from the site is coordinated and appropriate

procedural steps are in place, the Flood Emergency Plan will be produced in

liaison with SGC, BCC and the EA. The main objectives of the Flood Emergency

Plan would be to provide:

• An Emergency Route Plan – showing the escape route in different

circumstances, when necessary and safe to do so;

• Location of Safe Refuge – the location of a safe refuge area should be

made clear to users of the site;

• Practical Flood Advice – lists of provisions that will be recommended as

well as the best way to respond before and during an event;

• Guidance on Education and Training – increase awareness regarding the

risk of flooding by preparing a poster to accompany this evacuation plan;

• Information on local Flood Warning Services – the development should be

linked to the Environment Agency’s Flood Warning Service; and

• Defined roles and responsibilities during a flood event – listing the roles

and responsibilities of who will need to action on flood warnings and other

tasks required to prepare for flood events.

Fluvial/Tidal Flood Risk - Offsite

14.5.48. As discussed above the offsite effect posed to third parties due to the volume of

floodwater displaced by raising part of the Proposed Development Site is

considered minor adverse during operation.

Surface Water Flood Risk (Onsite/Offsite)

14.5.49. Surface water runoff from the Proposed Development will be managed during the

operational phase through the use of SuDS techniques. The Level 3 FRA

provides an outline drainage strategy to ensure runoff rates from the Proposed

Development do not exceed pre-development greenfield runoff rates.

14.5.50. Surface water runoff generated within the Proposed Development will drain via a

positive drainage system to an attenuation feature (of approximate attenuation

volume of 3,800m3). This feature will attenuate surface water runoff from the

Generation Station Site to pre-development greenfield rates for rainfall events up

to and including the 1 in 100 year (inclusive of climate change).

14.5.51. The water attenuation feature will be located in the Utilises, Services and

Landscaping Area, as illustrated in Figure 3-1 Volume III of this PEI Report. The

most likely options are that it will comprise a single water body, either located on

the eastern part of the Proposed Development Site, forming the boundary with

the CCR Site, and/or a linear feature along the southern boundary of the CCR

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May 2014 Page 14-27

Site adjacent to the PROW that is being proposed, as illustrated in Figure 3-1,

Volume III this PEI Report.

14.5.52. The outlet from the SuDS attenuation feature will discharge into the Red Rhine,

possibly via the Crook Marsh stream depending on the final location of the water

attenuation feature. Restricting the discharge rate to the pre-development rates

will ensure that flood risk posed to the Proposed Development and third party

land and property remains low.

14.5.53. The residual effect to the Proposed Development Site is considered to be minor

beneficial, whereas the residual effect to third party property and land is

considered to be negligible during operation.


14.5.54. The Proposed Development has a design life of approximately 30 years,

although the operational life may be extended beyond this, after which, the

station and associated infrastructure will be decommissioned. The

decommissioning phase is expected to be relatively short in duration, of the order

of approximately one year. Decommissioning will require appropriate method

statements and a demolition EMP to mitigate any adverse effects on surface and

groundwater receptors.

14.5.55. The potential for effects on the water quality attributes of nearby surface and

groundwater receptors will be similar to those identified for the construction

phase. Fuel and oils will be used by demolition machinery and the vehicles used

to remove waste materials from the site with the potential for pollution of surface

watercourses through spillage and/or leakage. There is also the potential for

crushed concrete and concrete dust to enter waterbodies either via windborne

dust or spillage of materials whilst in transit. However, these effects will be

temporary and localised, having a negligible effect on surface and groundwater

receptors.

14.5.56. The water supply pipeline will likely be capped at both ends and left in-situ. The

majority of other sub-surface structures are also likely to remain in in-situ,

therefore no significant effects on groundwater flow paths or groundwater

receptors are anticipated. Some minor re-profiling may be required once any

above ground structures have been removed, however no significant impacts or

effects groundwater receptors would be expected.

14.5.57. Taking into account the mitigation measures outlined for the construction phase,

which would be implemented during decommissioning, the residual effect is


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May 2014 Page 14-28


14.6.1. This section addresses all effects which cannot be eliminated through design

change or application of standard mitigation measures. An effect significance

level is attributed to residual effects that remain after prescribed mitigation

measures are taken into account. The main conclusions of this chapter are also

provided.

14.6.2. A summary of the significance level attributed to residual effects, which remain

after the application of prescribed mitigation measures is provided below.

14.6.3. The methodology adopted for this chapter (see Section 14.2) considers major or

moderate effects to be significant, and minor or negligible effects not to be

significant. As mentioned previously, it has been assumed that any construction

effects (short and medium term) are temporary and any operational effects (long

term) are permanent, unless otherwise stated.

Water Quantity and Quality

14.6.4. Table 14-8 indicates that during the enabling works and construction phase of the

Proposed Development, the effect significance attributed to residual effects

posed to water resources are all minor adverse. The exception to this is the

potential for contamination by oils, hydrocarbons and cement, which is

considered to be negligible following mitigation.

14.6.5. Incorporation of industry accepted construction methods will reduce the potential

for major pollution incidents to occur and thus further protect identified surface

water and groundwater receptors.

Table 14-8: Residual Effect Significance for Water Quantity and Quality during Construction

Phase (Temporary)

Potential Effect Importance of Receptor

Magnitude of Change (with mitigation)

Significance of Effect (Residual)

Water Quantity

Alteration to flow regime and hydro-morphology

Red Rhine (including Crook’s Marsh Stream) (High)

Low Minor Adverse


Stuppill Rhine (High) Low Minor Adverse


Tidal River Severn (Very High)

Neutral Minor Adverse

Alteration to shallow groundwater flow

Shallow Groundwater (high)

Low Minor Adverse

Water Quality

Increased sediment loading

Red Rhine (High) Low Minor Adverse

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May 2014 Page 14-29









Contamination by oils, hydrocarbons and cement

Red Rhine (High) Low Minor Adverse







Shallow Groundwater (High)

Low Minor Adverse


Deeper Groundwater (High)

Neutral Negligible

Nutrient Enrichment Red Rhine (High) Low Minor Adverse

Nutrient Enrichment Tidal River Severn (Very High)


14.6.6. Table 14-9 indicates that during the operational phase of the Proposed

Development the effect significance level attributed to residual effects posed to

water resources are either negligible or minor adverse. In accordance with the

significance of effects methodology (see Section 14.2) negligible and minor

adverse effects are not considered to be significant.

Table 14-9: Residual Effect Significance for Water Quantity and Quality during Operation Phase

(Permanent)




Water Quantity


Red Rhine (including Crook’s Marsh Stream) (High)

Neutral Negligible


Stuppill Rhine (High) Neutral Negligible




Alteration to shallow Shallow Groundwater Low Minor Adverse

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May 2014 Page 14-30




groundwater flow (high)

Water Quality


Red Rhine (High) Neutral Negligible







Red Rhine (High) Neutral Negligible







Shallow Groundwater (High)

Neutral Negligible


Deeper Groundwater (High)

Neutral Negligible

Nutrient Enrichment Red Rhine (High) Neutral Negligible

Nutrient Enrichment Tidal River Severn (Very High)


Nutrient Enrichment Stuppill Rhine (High) Neutral Negligible

14.6.7. On completion of the operational life of the Proposed Development, taking into

account the mitigation measures outlined above, the residual effect during

decommission considered to be negligible.

Flood Risk

14.6.8. The specific methodology for defining and assessing the significance of flood risk

as dictated by the requirements of the NPPF (Ref. 14-17) and Planning Practice

Guidance released in March 2014 (Ref. 14-18) is outlined in the FRA.

14.6.9. All flood risk receptors identified are classified as high importance receptors (i.e.

the Proposed Development Site and neighbouring third party property and land).

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May 2014 Page 14-31

14.6.10. Table 14-10 and Table 14-11 provide a summary of the effect of the Proposed

Development on the risk posed by all flood sources to identified receptors during

the construction and operation phases respectively.

14.6.11. Table 14-10 indicates that the construction phase (with incorporated mitigation)

will have a negligible to major beneficial effect on the fluvial and tidal flood risk

posed to the Proposed Development. This effect range (from negligible to major

beneficial) depends on the timing of a potential fluvial/tidal event, for example

prior to ground raising, the construction phase will have a negligible effect on

flood risk, however post ground raising the construction phase will have a major

beneficial effect on flood risk by reducing flood risk from high to low.

14.6.12. Table 14-10 also indicates that the effect of the construction phase on other flood

sources, such as surface water, groundwater and artificial flood sources are

either negligible or minor adverse.

Table 14-10: Construction Phase Effect on Flood Risk (Temporary)

Potential Receptor Flood Pathway Effect on Flood Risk (with

mitigation)

Fluvial

Proposed Development Site (on-site)

Overtopping of Red Rhine

Negligible to Major Beneficial during construction

Third Party Property and Land (off-site)

Negligible to Minor Adverse during construction

Tidal (including residual risk)

Proposed Development Site (on-site) Overtopping/Breach of Coastal

Defences

Negligible to Major Beneficial during construction


Negligible to Minor Adverse during construction

Surface Water

Proposed Development Site (on-site) Increase in Surface Water

Runoff Rates and Volumes

Minor Beneficial during construction


Minor Adverse during construction

Groundwater


Groundwater raising above ground levels

Negligible to Minor Beneficial during construction


Groundwater raising above ground levels

Negligible during construction

Artificial Sources


No Flood Source or Pathway




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May 2014 Page 14-32

Table 14-11: Operation Phase Effect on Flood Risk (Permanent)

Potential Receptor Flood Pathway Effect on Flood Risk (with mitigation)

Fluvial


Overtopping of Red Rhine

Major Beneficial during Operation


Minor Adverse during Operation

Tidal (including residual risk)

Proposed Development Site (on-site) Overtopping/Breach of Coastal

Defences

Major Beneficial during Operation


Minor Adverse during Operation

Surface Water

Proposed Development Site (on-site) Increase in Surface Water

Runoff Rates and Volumes

Minor Beneficial during Operation


Negligible during Operation

Groundwater

Proposed Development Site (on-site) Groundwater raising above

ground levels

Minor Beneficial during Operation



Artificial Sources


No Flood Source or Pathway




14.6.13. Table 14-11 indicates that the operation phase (with incorporated mitigation) will

have a major beneficial effect on the fluvial and tidal flood risk posed to the

Proposed Development and Proposed Development Site due to raising site

levels above model flood levels.

14.6.14. The operation phase will have a negligible to minor adverse impact on the

fluvial/tidal risk posed to third party property and land.

14.6.15. Table 14-11 also indicates that the effects from the operation phase on other

flood sources (onsite and offsite), such as surface water, groundwater and

artificial flood sources are either negligible or minor adverse.

Conclusions

14.6.16. A number of potential effects (adverse and beneficial) on water resources have

been identified as a result of the construction (including enabling works),

operational and decommissioning phases of the Proposed Development. The

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May 2014 Page 14-33

adopted assessment methodology considers moderate and major effects to be

significant, whereas minor or negligible effects not to be significant. The effect

significance level attributed to residual effects that remain after prescribed

mitigation measures are taken into account are outlined below:

• All residual effects posed to surface water and groundwater resources

during the construction phase (including enabling works) and operation

phase of the Proposed Development are either negligible or minor

adverse;

• No effects (beneficial or adverse) are deemed significant during the

construction (including enabling works) or operation phase, with no

adverse impact on WFD classifications of identified water resources;

• The raising of ground levels (above modelled flood levels) during the

construction phase will reduce the flood risk posed to the Proposed

Development to low, resulting in a major beneficial effect during both the

construction and operation phases of the development;

• Offsite the raising of ground levels (above modelled flood levels) during

the construction (and operation) phase will have a negligible to minor

adverse effect on the fluvial/tidal risk posed to third party property and

land;

• The construction phase and operational phase of the Proposed

Development will have a negligible effect on the risk posed by surface

water, groundwater and artificial flood sources to identified receptors.

14.7. Cumulative Effect Assessment

Overview

14.7.1. This section considers the cumulative impact of the Proposed Development and

associated infrastructure along with other consented schemes within the vicinity

on flood risk and surface and ground water receptors.

14.7.2. Consented and proposed schemes within the area which are considered

sufficiently close to give potential cumulative effects with the Proposed

Development have been identified and reviewed in terms of both the construction

and operational phase effects.

Construction Effects

14.7.3. During the construction phase the magnitude of cumulative effects and their

significance depends on the degree of which they overlap with each other.

14.7.4. Construction activities have the potential to create adverse effects on water

quality of local watercourses. Potential contamination of surface water runoff

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May 2014 Page 14-34

thorough accidental spillages could, in turn, impact upon local water quality. An

increase in the mobilisation of sediments in surface water runoff may have an

adverse effect on local water quality.

14.7.5. The cumulative schemes sufficiently close to the Proposed Development Site or

Red Rhine to have the potential to lead to cumulative effects are the Severnside

Energy Recovery Centre, the new Spine Access Road, the realignment of the

Red Rhine, and Central Park, all of which are currently under construction and

should be operational by the start of construction of the Proposed Development.

Avon Power Station is also sufficiently close to the Proposed Development Site

to lead to cumulative effects, however it is not a consented scheme and therefore

there is no guarantee it will come forward; it will also be physically separated from

the Red Rhine by the Spine Access Road.

14.7.6. Regardless, where best practice construction methodologies are adopted

(including the EA’s full PPG measures) during the construction phase, the

likelihood of these pollution events occurring is minimised, or the consequences

of the potential effects are managed and reduced. A minor adverse cumulative

effect on water resources is anticipated during the construction and operation

phases of the cumulative schemes.

Land Raising

14.7.7. In addition to the Proposed Development a number of other consented schemes

have already undergone or require land raising to mitigate fluvial/tidal flood risk

over the developments lifetime. Modelling undertaken to inform the Level 3 FRA

has been used to understand the volume of floodwater displaced by each of the

consented schemes during selected fluvial flood event and tidal breach

scenarios.

14.7.8. The land raising associated with the Central Park scheme is considered likely to

result in a moderate adverse effect on flood levels during an extreme tidal flood

event, regardless of the contribution associated with the Proposed Development.

The Hold the Line policy proposed within the Severn Estuary Shoreline

Management Plan 2 (Ref. 14-19)) reduces the likelihood of this moderate

adverse effect occurring to low.

14.7.9. The land raising associated with the Proposed Development is predicted to make

a negligible contribution to this significant cumulative effect and therefore the

Proposed Development has been assessed as non-significant. A substantial

amount of the land raising considered as part of this cumulative assessment has

already been completed (i.e. majority of the Central Park Site) and therefore

could be soon considered as the current baseline. This may require an

amendment to the assessment for the final ES.

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May 2014 Page 14-35

Impermeable Area

14.7.10. An increase in impermeable area due to development of consented schemes is

likely, as a large percentage of the local area to be developed is currently

undeveloped permeable or greenfield land.

14.7.11. Unmitigated, the increase in surface water runoff rates and volumes due to an

increase in impermeable area would have an adverse cumulative effect on the

hydrological characteristics of the Red Rhine catchment area.

14.7.12. However, in accordance with NPPF (Ref. 14-17), the Proposed Development will

include SuDS to ensure surface water runoff rates post development do not

increase, through the use of attenuation or infiltration techniques. Therefore, the

cumulative effects associated with the increase in impermeable is likely to be

negligible.

Operational and Decommissioning Effects

14.7.13. No additional cumulative effects are assessed for flood risk and water resources

during the operational phase, as it is expected that all developments will have

addressed any related issues during the construction phase. During the operation

phase the cumulative schemes will be required to operate in compliance with the

conditions of its planning consent and /or environment permits.

14.7.14. It is not expected that there would be any cumulative effects during

decommissioning, given the negligible effect predicted for the proposed

Development and different design lives for the cumulative schemes.


14.8.1. It is recognised that the Site baseline conditions may change between the

preparation of this PEI Report and the final ES, as outlined in Chapter 7:

Assessment Methodology. The Proposed Development Site is currently subject

to excavation, top soil stripping, and levelling in certain areas in order for third












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May 2014 Page 14-36

14.8.3. In particular, depending on the stage of works on Central Park, it may be

necessary to incorporate the new site levels on this cumulative scheme within the

baseline scenario, rather than continuing to consider it as part of a future

baseline or as a cumulative effect.

14.8.4. While the baseline conditions may change, and this may require the text in the

final ES to be updated, it is not anticipated that this would affect the assessment

or conclusions presented in this chapter and FRA.

14.8.5. A framework strategy for the Drainage Management Plan will be included as part

of the submission of the DCO.

14.9. References

Ref. 14-1 URS (February, 2013) Seabank3 EIA Scoping Report. Prepared for:

SSE Seabank Land Investments Ltd.

Ref. 14-2 The Planning Inspectorate (March, 2013) Scoping Opinion for

Proposed Seabank3 CCGT.

Ref. 14-3 Environment Agency Groundwater Vulnerability Map of the Southern

Cotswolds (Sheet 37), 1:100,000 Scale.

Ref. 14-4 Ordnance Survey (OS) Landranger Map, Bristol and Bath (Sheet

172), 1:50,000 Scale.

Ref. 14-5 Capita Symonds (March 2011) Avonmouth / Severnside Level 2

Strategic Flood Risk Assessment. Prepared for Bristol City Council,

South Gloucestershire, Lower Severn Drainage Board.

Ref. 14-6 Environment Agency (December 2009) Severn Tidal Tributaries

Catchment Flood Management Plan. Available at: www.environment-

agency.gov.uk [Accessed 8th May 2013].

Ref. 14-7 Landmark Group Limited (September 2012) Envirocheck Report,

centred on NSIP Development.

Ref. 14-8 Environment Agency (2009) Severn River Basin Management Plan.

Available at: www.environment-agency.gov.uk [Accessed 9th May

2013].

Ref. 14-9 Environment Agency (2013) Groundwater Aquifer Designation Map.


2013].

Ref. 14-10 Environment Agency (2013) Groundwater Source Protection Zone

Map. Available at: www.environment-agency.gov.uk [Accessed 7th

May 2013].

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May 2014 Page 14-37

Ref. 14-11 Environment Agency (2013) Flood Map. Available at:

www.environment-agency.gov.uk [Accessed 7th May 2013].

Ref. 14-12 Environment Agency (2013) Map of Flood Risk from Reservoirs


2013].

Ref. 14-13 Directive 2000/60/EC of the European Parliament and of the Council

establishing a framework for the community action in the field of

water.

Ref. 14-14 UK Technical Advisory Group Water Framework Directive Site,

Available at: http://www.wfduk.org/ [Accessed 25th June].

Ref. 14-15 Department for Transport (DfT), (2003); The Water Environment Sub-

Objective Transport Analysis Guidance (TAG) Unit 3.3.11, Available

at: http://www.dft.gov.uk/webtag/documents/expert/pdf/unit3.3.11.pdf

[Accessed 10th May 2013].

Ref. 14-16 Highways Agency (2009); Design Manual for Roads and Bridges Vol.

11 Environmental Assessment. Section 3 Environmental Assessment

Techniques. Part 10 Road Drainage and the Water Environment. The

Stationary Office (TSO).

Ref. 14-17 Department for Communities and Local Government (DCLG), (2012);

National Planning Policy Framework, Communities and Local

Government Publications.

Ref. 14-18 DCLG (2014); Planning Practice Guidance – Flood Risk and Coastal

Change, Communities and Local Government Publications.

Ref. 14-19 Environment Agency (2010) Shoreline Management Plan 2.

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PEI Report – Chapter 15 Archaeology and Cultural Heritage

15. Archaeology and Cultural Heritage

15.1. Introduction 15.1.1. This chapter identifies the location, type and significance of cultural heritage

assets and their setting within the DCO Site and surrounds, as well as providing an assessment of the effects of the Proposed Development on these assets and settings.

15.1.2. Heritage assets are defined as “a building, monument, site, place, area or landscape identified as having a degree of significance meriting consideration in planning decisions, because of its heritage interest’” (Ref. 15-1). Heritage assets include assets that are both designated under legislation and non-designated. The latter are mainly, but not limited to, assets identified by local planning authorities as having a degree of local interest or significance and are usually recognised by their inclusion within the local Historic Environment Record (HER) (Ref. 15-2).

15.1.3. The specific aims of the assessment reported herein are to:

• Identify and characterise designated and non-designated assets, both within the DCO Site and the defined study area;

• Assess the significance and setting of those assets;

• Identify areas disturbed by modern activity that might have affected the survival and significance of heritage assets;

• Assess the impact of the regeneration scheme on the significance and setting of heritage assets within the study area; and

• Outline strategies to mitigate any identified impact arising from the proposals upon heritage assets.

15.1.4. The assessment has been carried out in accordance with the Institute for Archaeologists (Ref. 15-3) Code of Conduct and their Standards and Guidelines and in accordance with policy and guidance, with specific reference to:

• Policies within the NPPF (Ref. 15-1);

• English Heritage ‘Conservation Principles Policy and Guidance’ (Ref. 15-4); and

• English Heritage ‘The Setting of Heritage Assets’ (Ref. 15-5).

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Consultation 15.1.5. A scoping request was submitted to the Planning Inspectorate in February 2013

to allow stakeholders the opportunity to comment on the proposed structure, methodology and content of this chapter. A summary of stakeholder comments and how they have been incorporated into this PEI Report chapter are provided in Table 15-1.

Table 15-1: Scoping Opinion Responses Relevant to Archaeology and Cultural Heritage



Relevant receptors should include those identified by English Heritage, together with others identified in consultation with BCC and SGC


English Heritage

This development could, potentially, have an impact upon a number of designated heritage assets and their settings in the area around the site and the ES should contain a thorough assessment of the likely effects, which the proposed development might have upon those elements, which contribute to the significance of these assets. Known heritage assets within close range of the proposed development include Kingweston House and its Historic Park, as well as the Grade II* listed-Bishops Farmhouse, Berwich Lane, Almondsbury.

Noted. These have been included in sections 15.3 and section 15.5 of this chapter

The ES should consider the potential impacts upon those heritage assets which are not designated.


A staged programme of archaeological investigations will be required before the potential impact of the scheme can be fully appraised, including geophysical and geotechnical surveys.


The proposed pipeline between Seabank 3 and Bristol WWTW will require mitigation.


A historic buildings assessment should be included to fully assess the impact on heritage assets that are designated listed buildings or conservation areas.


SGC The assessment should take into account the changing relief and the openness of the landscape which is such that some grade II heritage assets (which are by definition of national importance by virtue of their inclusion on the national list) may suffer greater impacts than other closer heritage assets that experience less visual impact by virtue of changing topography or other buildings and landscape features.

See sections 15.2, 15.3 and 15.5 of this chapter.

The EIA should make reference to the settings or direct impacts on undesignated heritage assets as well as on designated ones, in order to satisfy policy requirements.

See sections 15.3 and 15.5 of this chapter.

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A combination of electromagnetic and caesium vapour geophysical surveys should be undertaken as soon as possible in order to try to clarify potential for surviving archaeological deposits to occur within the affected areas of the site and within the area of search for the proposed cooling water pipeline.


The ES should refer to the NPPF or the 1990 Planning (Listed buildings and conservation areas) Act or any English Heritage guidance on the assessment of significance and setting for heritage assets.

See Appendix D, Volume II of this PEI Report

BCC Any works to provide connections from Seabank 1 & 2 to the proposed Seabank 3 must be fully considered.


Further details and satisfactory mitigation should be put forward regarding the proposed pipeline connection to the Bristol WWTW.


15.1.6. Following the receipt of the Scoping Opinion, consultation has been on-going

with the County Archaeologists for SGC and BCC, as well as English Heritage, and is referred to throughout this chapter. The consultation was also used to identify if any of the mitigation proposals put forward had been carried out as part of any other development schemes in the area.

Legislation and Planning Policy Context 15.1.7. A summary of the planning policy relevant to this chapter and the Proposed

Development is presented in Appendix D, Volume II of this PEI Report.

15.1.8. In terms of relevant legislation, the Planning (Listed Buildings and Conservation Areas) Act 1990 (Ref. 15-6) establishes a requirement to have special regard to the desirability of preserving the setting of a listed building or conservation area.

15.2. Assessment Methodology and Significance Criteria 15.2.1. This assessment methodology has been informed by the Archaeology and

Development in the North Avon levels Guidance Note (Ref. 15-7) which details SGC’s approach to the conservation and protection of the archaeological heritage and recommends strategies for assessment.

15.2.2. The assessment has also been informed by a number of previous investigations listed in the baseline section.

15.2.3. This research has been augmented by a site walkover undertaken by an archaeological and built heritage consultant. The purpose of the site visit was to verify the current ground conditions and identify any areas of recent ground disturbance which would have the potential to remove below-ground deposits.

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The site visit was also used to visit the identified designated heritage assets and any non-designated heritage assets which may be physically impacted by the Proposed Development, and to identify their setting.

Study Areas


15.2.4. A 1km inner study area has been used to identify designated and non-designated assets which have the potential to be affected by the development proposals within the Proposed Development Site. This inner study area was defined by the limited potential for impacts upon the setting of assets beyond this point. This area is considered to be sufficient to accurately represent the archaeological and architectural character of the immediate area.

15.2.5. Due to the potential for impact upon listed buildings, a secondary study area of 2km was initially considered, but due to no listed buildings being present within this radius it has not been considered further in this assessment.

15.2.6. All designated assets within a 5km outer study area were assessed. A Zone of Theoretical Visibility (ZTV) to a distance of 10km from the Proposed Development was also assessed to determine the presence of designated assets within the ZTV, as illustrated in Figure 15-1 (Volume III of this PEI Report).


15.2.7. The proposed cooling water pipeline will be located within a predominantly 30m wide corridor, running predominantly adjacent to the existing cooling water pipelines that serve Seabank 1 & 2. The land through which these existing pipelines pass has already been archaeologically assessed (Ref. 15-8).

15.2.8. The study area for the proposed cooling water pipeline is a 500m radius from the ‘Other DCO Land’ within which it resides. This was considered adequate to determine the effects of the proposed pipeline and was agreed in liaison with English Heritage, SGC and BCC.

15.2.9. The proposed electrical connection runs through (or under) the existing Seabank 1 & 2 site on previously disturbed land and is therefore not assessed further in this chapter. It has been assumed that there are no archaeological remains beneath this part of Seabank 1 & 2 that would be affected by the cables, and given they would be located underground or in cable racks up to 2m high the visual effect on the settings of heritage assets in the surrounding area is considered to be imperceptible.

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Impact Assessment and Significance Criteria 15.2.10. This assessment takes into account the significance (importance) of each asset,

and the likely impact (without mitigation) of the Proposed Development upon them, in order to appraise the potential effects. Only those heritage assets where there is a potential for effects have been included within this assessment.

15.2.11. For the purposes of this assessment, the term ‘significance’ is that as defined in Annex 2 of the NPPF (significance for heritage policy) (Ref. 15-1). In this context significance is defined as the value of the heritage asset arising from heritage interest, which may be archaeological, architectural, artistic, or historic. Significance can also be derived from an asset’s setting. Taking these criteria into account, each identified heritage asset can be assigned a level of significance in accordance with a five-point scale, as shown in Table 15-2.

15.2.12. Having identified the importance of the heritage assets, the next stage is to assess the level or magnitude of the change, or impact, from the development. Impacts can be considered in terms of direct, indirect and cumulative. The sources of impact may arise during construction, operation and/or decommissioning, and can be characterised in terms of timing, scale, duration, reversibility and the likelihood of the impact occurring and can be beneficial or adverse.

Table 15-2: Criteria for Establishing the Importance of Heritage Assets Sensitivity (significance) of the Receptor

Criteria

Very High Remains of inscribed international importance, such as World Heritage Sites. Grade I and Grade II* Listed Buildings. Grade I and Grade II* Registered Parks and Gardens. Scheduled Monuments. Registered battlefields Non-designated archaeological assets of schedulable quality and importance. Non-designated buildings, monuments, sites or landscapes that can be shown to have particularly important qualities in their fabric or historical association.

High Grade II listed Buildings. Conservation Areas. Grade II Registered Parks. Assets of high archaeological resource value as identified through consultation.

Medium Locally listed buildings as recorded on a local authority list Non-designated buildings, monuments, sites or landscapes that can be shown to have important qualities in their fabric or historical association. Historic Townscapes with historic integrity in that the assets that constitute their make-up are clearly legible

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Sensitivity (significance) of the Receptor

Criteria

Low Non-designated buildings, monuments, sites or landscapes of local importance and of modest quality Locally important historic or archaeological assets, assets with a local value for education or cultural appreciation and of medium archaeological resource rating, Assets that are so badly damaged that too little remains to justify inclusion into a higher grade, Parks and gardens of local interest.

Very Low Assets identified as being of no historic, evidential, aesthetic or communal interest. Assets whose values are compromised by poor preservation or survival or of contextual associations to justify inclusion into a higher grade.

15.2.13. The assessment of impact includes the consideration of an asset’s setting, whether designated or not. The setting of a heritage asset varies from case to case and cannot be generically defined. Setting contributes to the significance of an asset, and should not be considered separate from it. English Heritage guidance is that an assessment of the impact of a proposed development should identify whether the development would be acceptable in terms of the degree of harm to an asset’s setting. Fundamental to the assessment of impacts on setting is the principle that a visual relationship may contribute to setting, but does not define it.

15.2.14. The magnitude of a change can be judged on a five-point scale, as shown in Table 15-3. The impact score is arrived at without reference to the importance of the asset and the change is assessed without taking into account any subsequent mitigation proposals.

Table 15-3: Criteria for Establishing the Magnitude of Change on a Cultural Heritage Asset Impact Rating Description of Impact High Change such that the significance of the asset is totally altered or destroyed.

Comprehensive change to setting affecting significance, resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.

Medium Change such that the significance of the asset is affected; or Changes such that the setting of the asset is noticeably different, affecting significance resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.

Low Change such that the significance of the asset is slightly affected; or Changes to the setting that have a slight impact on significance resulting in changes in our ability to understand and appreciate the resource and its historical context and setting.

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Impact Rating Description of Impact Minimal Changes to the asset that hardly affect significance; or

Changes to the setting of an asset that have little effect on significance and no real change in our ability to understand and appreciate the resource and its historical context and setting.

No change The development does not affect the significance of the asset; or Changes to the setting do not affect the significance of the asset or our appreciation of it.

15.2.15. The initial assessment of the significance of effect is undertaken at this stage of the process. The only mitigation which is taken into account at this stage is any mitigation measures incorporated into the design. No additional mitigation such as excavation or recording is taken into account at this stage. It should be recognised that some environmental mitigation measures, for example landscaping or areas of ecological compensation, can themselves be a source of impact.

15.2.16. The final and concluding assessment of the level of overall significance of the effect takes into consideration additional mitigation such as archaeological excavation or building recording. The statement of the residual effect is arrived at by cross-referencing between the importance of the asset (Table 15-2) and the magnitude of change (Table 15-3), as shown in Table 15-4. The assessment of the overall significance of effect of the scheme on each identified heritage asset can be negligible, adverse or beneficial. Effects are only considered to be significant if they are major or moderate.

Table 15-4: Matrix for Establishing Overall Significance of Effect

Importance of Asset

Magnitude of Change No Change Minimal Low Medium High

Very High

Negligible Minor Major Major Major

High

Negligible Minor Moderate Major Major

Medium Negligible Minor Minor Moderate Major

Low Negligible Negligible Minor Minor Moderate

Very Low Negligible Negligible Negligible Negligible Negligible

Uncertain Determinable only on definition of the asset

15.2.17. Within national planning policy, principally the NPS and NPPF, effects are considered in terms of ‘substantial’ or ‘less than substantial’ harm. Paragraph 132

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of the NPPF states that substantial harm to a designated asset should be wholly exceptional and, in accordance with paragraph 133, weighed against the public benefit of the scheme.

15.2.18. The NPPF does not provide a qualitative definition of what constitutes ‘substantial’ or ‘less than substantial’ harm. The assessment is required to report on the significance of an effect and does not make a judgement on whether ‘substantial’ or ‘less than substantial’ harm will be caused. The judgement of whether an effect causes ‘substantial’ harm is based on whether the effect on the individual asset has an impact on the wider historic environment; i.e. where the significance of an asset is such that its loss would be detrimental to the understanding of the unique values of the wider asset type. This may include extensive physical damage to an asset or loss of critical elements of an asset’s setting. The identification of ‘substantial’ harm is therefore one of professional judgment and not directly equitable to the significance of the effect.

Key Parameters for Assessment 15.2.19. The variation in building dimensions presented in Chapter 4: Project Description

under the Rochdale Envelope principle is an important consideration for this PEI Report.

15.2.20. However, regardless of the difference in presented maximum and minimum parameters it is assumed that the majority of the main works area will be cleared of vegetation and topsoil, no matter what the final sizing and layout of the buildings are. The Rochdale Envelope parameters do not, therefore, significantly affect the approach utilised in either the archaeological or cultural heritage assessments, and consequently the outcome of these assessments will not vary. Therefore, no further discussion of the Rochdale Envelope parameters is provided in this chapter.


Previous Archaeological Investigations 15.3.1. Archaeological investigations within the study area for the Proposed

Development Site and associated infrastructure have been assessed and are fully listed in Appendix H (Part 1), Volume II of this PEI Report, and their locations illustrated on Figure 15-2 (Volume III of this PEI Report) for the Proposed Development Site and Figure 15-3a and Figure 15-3b (Volume III of this PEI Report) for the associated infrastructure.

15.3.2. The assessment has also been informed by a number of previous archaeological and geotechnical investigations described in this section and illustrated in Figure 15-4, Figure 15-5, and Figure 15-6 in Volume III of this PEI Report.

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The Proposed Development Site

15.3.3. A number of investigations have taken place within the Proposed Development Site, in the Seabank 1 & 2 site, and in close proximity to the proposed cooling water pipeline. What follows is a description of the most relevant investigations that have been undertaken, either within or in very close proximity to the Proposed Development Site and proposed cooling water pipeline corridor.

15.3.4. An excavation took place within the Proposed Development Site as a result of discoveries during watching brief monitoring during the laying of the existing gas pipeline that extends through the Proposed Development Site (known as the Abson pipeline) (Event No 11055 14313/3, Field 158 (Ref. 15-10; Ref. 15-11, Ref. 15-27). The watching brief revealed a well preserved buried land horizon at 6.62m AOD). A buried topsoil was sampled and carbon dated to 2140-1740 Calibrated BC. Pollen analysis revealed a high quantity of fern spores probably indicating the lower horizons of a terrestrial soil. Diatom analysis showed poor preservation but noted that both brackish and freshwater taxa were present. Three separate alluvial layers, 0.4m, 0.5m and 1.2m thick overlaid the buried topsoil. Of archaeological significance, the watching brief revealed two ditches (Ditches 19 and 37, as shown on Figure 15-4 (Volume III)), the fills of which contained late-3rd to mid-4th Century AD pottery and fragments of quern stone. A bone spindle whorl was also found. Several thin alluvial layers sealed the ditch fills. The upper alluvial layers also contained pottery of a similar date.

15.3.5. A pit or ditch terminus was also revealed (Ditch 42) together with a further truncated ditch orientated east to west. Fills of both features also contained pottery of 3rd to 4th Century AD date.

15.3.6. A Ridge and Furrow Cultivation (2) is located within the northern part of the Proposed Development Site, referred to as New Pill Gout Chitterling Gout, Pilning (SGSMR18999).

15.3.7. The evidence revealed in the excavation suggests the presence of a settlement of 3rd to 5th century date being present in the vicinity. The evidence corresponds closely with data retrieved for excavations at Crook’s Marsh Farm (Ref. 15-12).

15.3.8. A few hundred metres to the southeast of the Generating Station Site, and within the CCR Site, a mettled trackway, Romano British ditch, and medieval ridge and furrow was revealed during a watching brief in 1997 (Event no 12759) (Ref. 15-13). To the west of the Generating Station Site, a desk top study (Event no 19090) of the area for the proposed Severnside Energy Recovery Centre was undertaken in 2009. Much of the area had been developed during the 1960’s, but areas to the north had suffered less damage and had archaeological potential.

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15.3.9. A barrage balloon anchor (SGSMR19088 and associated huts (SGSMR 19088) were recorded in the study area. The archaeological fieldwork identified a consistent alluvial sequence within all the evaluation trenches. Organic strata, observed within the boreholes, and interpreted as saltmarsh deposits were seen in evaluation trenches 3, 4 and 6 sloping downwards towards the west. These sediments are interpreted as being representative of mud flats that were only occasionally inundated by tidal waters, thereby allowing plant communities to develop.

15.3.10. The stone footings and concrete floor surface of a post-medieval building were identified within trench 5, 10m to the west of an in-filled boundary ditch. Both the building and the ditch are depicted on the 1881 1st Edition OS map. No datable material indicative of the construction date of the structure was recovered from the foundation trenches of the building, but material broadly dated from the late 18th and 19th century was recovered from bedding material for a floor surface, demolition and abandonment deposits.

15.3.11. An archaeological evaluation was undertaken by Cotswold Archaeology in August 2010 and to the northwest of the Generating Station Site (Event no 21030). Five trenches were excavated revealing a consistent sequence of alluvial deposits which contained inorganic material between 2.9m and 5.65m AOD. The stone footings of a post medieval building were also revealed within trench 5.

15.3.12. Two trenches were excavated immediately to the northwest of the Generating Station Site, to the north of the Red Rhine. The identified geological deposits comprised alluvium overlying the Wentlooge Formation. A Roman ditch and pit were present in one trench and could be seen to survive from within 0.5m of the present ground level. Parallel to and approximately 4m away from the Roman ditch was a post medieval ditch. An organic deposit at the top of the Wenlooge Formation was recorded in both trenches at 4.1m and 4.3m AOD respectively.

Other DCO Land

15.3.13. In terms of the associated infrastructure there have been a number of investigations along the route of the current cooling water pipeline servicing Seabank 1 & 2, which the proposed water pipeline shall follow. A Desk Study (Event no 20076, (Ref. 15-14) for land close to the northern end of the pipeline route noted that the study area for the assessment lay close to a Second- to Fourth-century site at Crook's Marsh Farm, which was excavated in the late 1970s. The site itself was adjacent to the site of Worthy Farm which was in existence by the 13th Century. Ridge and Furrow also covered the land within the study area. Two trenches were excavated, one at a right-angle to the longer trench and beginning midway along it. No archaeological features or finds were recorded (Event no 20077). Event no 20761 is evidence from the Ordnance

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Survey first edition 1:2500 plan (Gloucester Sheet LXXI.10) which records Chittening Farm on the eastern side of Severn Road.

15.3.14. Chittening Stream runs parallel with Severn Road on its east side. Between April and May 2007 an archaeological excavation was carried out at the site of Washingpool Farm, Chittening Road, Severnside by Bristol and Region Archaeological Services (BaRAS (Event No 24536)). A single trench, measuring 20m long by 4m wide was excavated at Event no 20021. Elements of Washingpool Farm (2172M) were found at the south end of the trench, including a mortared stone wall and cobbled areas. All dated to the post-medieval period. A large pond feature of early nineteenth-century date was also recorded. The trench was excavated to a maximum depth of 2m below the ground surface (4.6m AOD).

15.3.15. A desk study at Estuary Industrial Estate, Chittening Road, Avonmouth (Event no 24616) identified that the Estuary Industrial Estate was agricultural land in low lying salt marsh until post-medieval development. The area was bisected by a local routeway (possibly a drove) named on later plans as Washingpool Lane. Green Splot Farm (2170M) was established at the southern end of the Estuary Industrial Estate between 1773 and 1830. During the First World War the adjacent site was developed as a munitions factory (2750M) complete with its own rail infrastructure. Two storage buildings associated with this facility are depicted on part of the Estuary Industrial Estate on a plan of the site dated 1918. During the 1950s the former munitions factory was adapted for light industrial use and a secondary phase of rail infrastructure was added. Chittening Road was first depicted on the OS plan of 1949 and by 1969 Green Splott Farm and Washingpool Lane had been replaced on the site by industrial warehousing.

15.3.16. In 1996, BaRAS undertook a desk based assessment and excavation for the route of the existing cooling water pipelines serving Seabank 1 & 2 (Event no 20079). The study concluded that the pipeline would affect only one known archaeological site, Washingpool Farm. Other elements of the historic landscape, particularly fields with surviving ridge and furrow, hedges and drainage ditches, were also identified as being affected. It was suggested by the authors that the site of Washingpool Farm be archaeologically evaluated, and that an archaeological watching brief be carried out during the excavation of the pipeline include a programme of palaeoenvironmental sampling. The watching brief in 2008 on geotechnical pits for the extant pipeline recorded only one pit and no further archaeological features (Event no 20080).

15.3.17. The watching brief on the installation of the existing cooling water pipelines (Event 20832) took place between March and June 1997. The watching brief was maintained during construction of the water pipeline between Bristol WWTW and

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the Seabank 1 & 2 station by Bristol and Region Archaeological Services (Ref. 15-15; Ref. 15-16).

15.3.18. The pipeline route was excavated by 360 degree tracked excavator except where it crossed fixed infrastructure, roads or railway line when directional drilling was used. No archaeological features and few finds were observed during the work. However, several significant geoarchaeological observations were made.

15.3.19. On the first section of the pipeline, between ST 5337 7966 and ST 5346 7987, a thin dark-brown organic soil was observed at a depth of 0.31m AOD below the ground surface. It was suggested that the layer may have represented "a buried former topsoil." At ST 5339 8023 on the second section an horizon of dark-brownish clay 0.06m thick and containing organic material was observed at 4.7m AOD. This returned a radiocarbon date of 3930 +/- 50 BP (Wk 5804) giving a date of 2580-2290 Cal BC (to a 2-sigma confidence using Oxcal).

15.3.20. A similar band of organic clay exposed at location ST 5347 7986 was identified at 4.65m AOD. The excavation of the segment of the route alongside the railway exposed a thin layer of dark-grey organic clay at ST 5316 8080. This was at an elevation of 4.325m AOD. This context was noted intermittently along this section of the pipeline trench.

15.3.21. At ST 5344 8058 a further lens of clay 0.05m thick and at an elevation of 4.95m AOD was sampled for radiocarbon dating. This produced a date of 4780 +/- 90 BP (Wk 5805), 3780-3360 BC at a 2-sigma calibration.

15.3.22. A further organic clay horizon was exposed at location ST 5349 8050. This was at an elevation of 5.04m AOD and yielded a radiocarbon date of 3920 +/- 60 BP (Wk 5806), which was calibrated to give a date of 2580-2200 BC.

15.3.23. During monitoring of the pipeline segment from Rockingham to the Sevalco factory on Chittening Road, a dark-grey organic clay 0.02m thick was observed at location ST 5327 8129. It was at an elevation of 4.05m AOD. Palaoenvironmental analysis of the samples of the clays, including wet-sieving produced no visible organic remains. The samples were also subject to loss on ignition tests which indicated that the organic content ranged between 6.8% and 7.16%. It was noted that the radiocarbon dates obtained from the samples fell within the broad range c.3500-2000 Calibrated (Cal) BC which had been established for deposits at similar elevations during work elsewhere in the North Avon Levels. The archive for the work was deposited with Bristol Museum and Art Gallery under the accession number BRSMG CMAG 1997.0021.

15.3.24. In 2009, four archaeological trenches and eight trial pits were excavated at Smoke Lane (Event 20955). These trenches revealed a sequence of alluvial deposits including an organic clay silt at a depth of 2.3m and 2.55m below the

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present ground surface. A sample from this deposit produced a radiocarbon date with a calibrated date range between 2580 BC and 2190 BC, with a 65.8% probability of dating between 2470 BC and 2280 BC. No artefactual remains were recovered from this deposit.

15.3.25. In trench 1, a large ditch that was visible as a surface depression was recorded. This feature was cut through the upper layers of alluvial deposits and no finds were recovered from the fill. The evaluation recorded no other archaeologically significant material. A desk assessment undertaken in advance of construction of the fire service training centre (Event no 20912) revealed evidence for ridge and furrow of possible medieval date within the study area. This was recorded by an air photograph of 1941 and the site itself was never developed.

15.3.26. A geophysical survey was undertaken by Stratascan on the south side of Smoke Lane in 2001. The survey covered 2.7ha undeveloped grassland (Event no 20937). Several anomalies were recorded, some associated with modern features including pipeline and fence lines. The survey also identified probable remnants of ridge and furrow across much of the site as well as two possible palaeochannels roughly in its centre (Ref. 15-17). A desk study undertaken by GGAT in the area of the proposed pipeline in 1995 (Event no 20056) argued that the landscape in the general area is of medieval or post-medieval origin but that within the study area "the cumulative effects of past development have covered or removed virtually all traces of the pre-20th century landscape within the Merebank/Lakeside area". Two known archaeological sites were identified: Madam House Farm and the Mere Bank. It was suggested that the area should be subject to archaeological evaluation to identify any buried archaeological sites.

Geophysical Survey 2013

15.3.27. A Ground conductivity survey was undertaken by Terradat in May 2013 and the results are presented in Figure 15-7a (Volume III of this PEI Report); Figure 15-7b (Volume III) and Figure 15-7c (Volume III) present the geophysical results overlaid with the single-shaft layout and the multi-shaft layout respectively. The investigation was carried out using caesium vapour magnetometery and electromagnetic ground conductivity surveying techniques. This is in accordance with the scoping response made by SGC.

15.3.28. The general survey objectives are detailed below:

• To investigate the archaeological potential of the Generating Station site;

• To investigate the palaeo-environmental potential of the Generating Station site; and

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• To assess the presence /absence of potential archaeological anomalies that might be present.

15.3.29. The survey indicated the presence of a small zone of low conductivity correlating with a topographically raised area forming a small island feature. The area northwest of Minors Lane is mainly characterised by a network of major drainage ditches associated with a central, broadly north-south orientated, double-ditch feature, probably representing an old trackway. The fields delimited by this network of ditches have ridge and furrow, cut by minor drainage ditches. No certain pre-ridge and furrow archaeological features have been detected, although some possible features were tentatively identified along the northern margin of the ‘island’. The strong magnetic anomalies associated with the pipelines preclude identification of the line of the early ditches observed during their construction – a problem further compounded by the similar alignment of the Roman ditches and the ridge and furrow in many cases.

15.3.30. Broad features in the magnetic data (and to a lesser extent the conductivity data) provided some evidence for early sedimentary features, possibly palaeo-channels, which are orientated roughly east-west on the north side of the island (GPW4-GPW2) but swing around it to be orientated northwest-southeast in GPW3. Evidence for the palaeo-channels southeast of the modern road is slight, and the broad variations of conductivity in this area may be more a product of the modern topography.

Archaeological Monitoring of Geotechnical Survey

15.3.31. Archaeological monitoring of ten California Bearing Ratio (CBR) testing was undertaken by URS in October 2013 in accordance with a specification prepared by URS in consultation with David Haigh, the Archaeological Advisor to SGC and Vanessa Straker, the Regional Scientific Advisor at English Heritage. The monitoring was required to observe any physical potential for archaeological or palaeoenvironemental remains present in the location of the Geotechnical Investigation (GI). The results are presented in a brief report in Appendix H (Part 2), Volume II of this PEI Report.

15.3.32. The location of each investigation was marked by the geotechnical contractor and an area approximately 1m2 excavated by hand to a depth of 0.2-0.3m below current ground level and are illustrated in Figure 15-8 (Volume III of this PEI Report). The pits were excavated under direct archaeological supervision, in level spits, until either the top of the first archaeological horizon or undisturbed natural deposits are encountered. The resulting surface was inspected for archaeological remains and cleaned if necessary and practicable.

15.3.33. Only two Geotechnical Investigation (GI) pits contained evidence of archaeological remains. CBR001 contained a possible reworked plough soil

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containing pottery of likely Romano British date. CBR007 was located on a low visible mound towards the southern central edge of the Generating Station Site, near the southern perimeter of the centre of the Proposed Development Site. The mound was also identified by the geophysical survey, as shown in Figure 15-7a (Volume III of this PEI Report). The GI pit contained evidence of a reworked plough soil which contained three shards of pottery of late medieval date and several large pieces of unworked limestone. The combined evidence suggests the presence of a possible house platform of later medieval date.

15.3.34. A geotechnical transect from the 2013 investigation is presented in Figure 15-9 (Volume III of this PEI Report).

Historic Environment Assets

15.3.35. No designated archaeological assets have been identified within the 1km study area for the Proposed Development Site or Other DCO Land (which together constitute the DCO Site). Seven non-designated archaeological assets have been identified within the Proposed Development Site and Other DCO Land. All of the assets are catalogued in Appendix H (Part 1), Volume II of this PEI Report and shown on Figures 15-2 (Volume III of this PEI Report) for the Proposed Development Site and Figure 15-3a (Volume III of this PEI Report) and Figure 15-3b (Volume III of this PEI Report) for the associated infrastructure. The reference numbers are referred to in the text by their SGC/BCC HER reference number.

Designated Assets

15.3.36. All of the designated assets within 5km are illustrated on Figure 15-10 (Volume III of this PEI Report).

15.3.37. There are no designated assets within the Proposed Development Site or Other DCO Land or 1km study area.

15.3.38. There are five Scheduled Monuments with 5km and fourteen Grade I listed buildings and 14 Grade II* buildings within 5km. Most of these are concentrated at Blaise Hamlet and Kings Weston to the south of the Proposed Development Site or Other DCO Land.

15.3.39. There are 136 Grade II listed buildings, none of which are located within 2km of the Proposed Development Site. For this reason the latter have not been assessed within this PEI Report.

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Table 15-5: Scheduled Monuments, Registered Parks and Gardens and Grade I and II* Listed Buildings within 5km of the DCO Site

Ref No Description Period Designation Assessed Importance

1006999 Part of a minor Romano-British villa at Long Cross Roman Scheduled

Monument Very High

1021291 Heavy Anti-aircraft battery 520m east of Holes Mouth Modern Scheduled

Monument Very High

1020664 The Mere Bank and flanking ditches Iron Age Scheduled

Monument Very High

1004530

Blaise Castle. Three tower gothick style castle built (1795-9, listed grade II*)

Iron Age, Roman, Medieval, Post-Medieval

Scheduled Monument and Listed Building

(GII*)

Very High

1002479 King's Weston Hill camp, Henbury

Iron Age Scheduled Monument Very High

1001426

Blaise Castle and Hamlet Mid C18 landscape garden overlaid by late C18 landscape park,

Post-Medieval

Registered Park and Garden Very High

1000360

Royal Victoria Park Villa grounds of 12ha designed, along with the house, by Humphry Repton.

Post-Medieval


1000335 Kings Weston House

Post-Medieval


1202260 Blaise Hamlet, Double Cottage Post-Medieval

Grade I Listed Building Very High

1202261 Blaise Hamlet, Rose Cottage Post-Medieval


1202262 Blaise Hamlet, Circular Cottage Post-Medieval


1202263 Blaise Hamlet, Vine Cottage Post-Medieval


1202264 Sundial to the middle of the green at Blaise Hamlet

Post-Medieval


1202338 Loggia approximately 50m north of Kings Weston House

Post-Medieval


1202339 The echo, approximately 300m South East of Kings Weston House

Post-Medieval


1207747 Blaise Hamlet, Oak Cottage Post-Medieval


1207760 Blaise hamlet, Dutch Cottage Post-Medieval


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Ref No Description Period Designation Assessed Importance

1209729 Kings Weston House Post-

Medieval Grade I Listed

Building Very High

1209747 The Brewhouse, Kings Weston House

Post-Medieval


1282246 Blaise Hamlet, Dial Cottage Post-Medieval


1282247 Blaise Hamlet, Sweetbriar Cottage

Post-Medieval


1282285 Blaise Hamlet, Diamond Cottage Post-Medieval


1128857 Bishop's Farmhouse Post-Medieval

Grade II*Listed Building Very High

1187186 Two lodges and attached garden walls opposite former Kings Weston stables

Post-Medieval


1187199 Police station and attached walls to north east and south west, former Kings Weston stables

Post-Medieval


1202278 Castle lodge and gateway, Blaise Castle Estate

Post-Medieval


1202280 Timber lodge, Blaise Castle Estate

Post-Medieval


1205113 Church of St Mary the Virgin Post-Medieval


1205137 Memorial To Scipio Africanus 10m North West Of South Porch Of Church Of St Mary

Post-Medieval


1208115 Blaise Castle Post-Medieval


1279500 Blaise Castle House And Attached Wall

Post-Medieval


1282073 Gothic Arch Set In Garden Of Number 5, Longacre (Number 5 Not Included)

Post-Medieval


1293355 Model Dairy Approximately 60m East Of Blaise Castle House

Post-Medieval


1321095 Church Of All Saints Post-Medieval


1321097 Archway To Over Court Post-Medieval


1409175 Severn Tunnel East Portal (BSW1101)

Post-Medieval


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Non Designated Assets within 1km

15.3.40. In addition to the assets identified from the HER, a number of potential heritage assets have been identified from examination of the historic mapping for the Proposed Development Site. These assets are no longer extant and most have been destroyed by later construction, such as the underground gas and water pipelines beneath the Site. Only those assets which have the potential to be disturbed as part of the Proposed Development, for example if they are in areas which have seen little modern disturbance or are in areas of proposed new build, are discussed in this chapter.

Prehistoric (10,000BC - AD43)

15.3.41. One archaeological asset has been identified within the study area dating from the prehistoric period. Early Peat deposits (17668) containing burnt material (mainly plant material of Bronze Age date) were recorded at this site in bore holes, within a trial trench and during watching brief observations (Ref. 15-28). They were intermittent and no associated archaeological deposits were recorded.

15.3.42. Just beyond the south and north boundaries of the Generating Station Site are the locations of two possible earthwork enclosures (2994/5), delineated with ditches and surrounded by ridge and furrow, indicating the possibly site of a past farmstead. The two enclosures are contiguous and sub-rectangular in form.

15.3.43. To the south of the Generating Station Site, a square enclosure lying within an area of ridge and furrow is recorded in the South Gloucestershire HER (SGHER) as Neolithic in Date (5224). The remains comprise three sides of a rectangular enclosure defined by earthworks. Another square shaped enclosure (5226) also recorded as Neolithic in date is located in small field to the northwest of Crook’s Marsh Farm. A further Neolithic or late prehistoric enclosure (5229) is located in field just north of Shipman's Gout to the north of Vimpennys Common. A prehistoric enclosure (5230) surrounded by ridge and furrow abuts the secondary rhine on the south side of Minors Lane.

15.3.44. A buried land surface of early prehistoric date is located at Elmington Farm, Almonsbury (6449). It consisted of a peat deposit containing well-preserved Phragmites was observed in a trial pit in 1990 (Ref. 15-18).

15.3.45. A prehistoric enclosure (6677) is located at Hallen Marsh, Bristol.

15.3.46. An area of peat deposit (7081) probably part of the submerged forest deposit at Severn Beach is marked on the 1:100,000 OS Maps to the southwest of Severn Beach.

15.3.47. A palaeo-environmental borehole sample was taken from a location within the Generating Station Site and is recorded on the SGHER (14325, 14326). A

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detailed report on the results is presented in the Pucklechurch to Seabank Pipe Line Archaeological report (Ref. 15-11).

15.3.48. Mesolithic Activity has been recorded in a buried land surface at Willow Farm Minors Lane Hallen, Bristol(20104). The Holocene stratigraphy at Willow Farm overlies a 0.28m thick layer of soliflucted flint/chalk gravel and silt at 16.36m (-9.90m AOD), below ground level (bgl) which in turn overlies the Mercia Mudstone Group bedrock (see Figure 15-6 (Volume III of this PEI Report)). A soil pre-dating 7310-7030 Calibrated BC is the first Holocene stratum, but this terrestrial unit it overlain by lagoonal strata, then a freshwater fen peat dating from 7310-7030 to 6440-6250 Calibrated. BC. Magnetic susceptibility evidence from the peat suggest that the fen surface was been burnt as it accreted, while considerable quantities of microscopic charcoal were noted at the same depths during the palynological study. The burning of the vegetation may indicate direct human activity either to prepare for agricultural activity or to aid hunting.

Roman (AD43 – 410)

15.3.49. Located within the western part of the Generating Station Site, a series of ditches (14323) containing Roman material was noted initially during a watching brief which was followed by excavation (Ref. 15-19).

15.3.50. A few hundred metres to the south is evidence of Romano British occupation revealed by extraction of alluvial clay by the Severn Valley Brick Company (4896). A series of ditches, some probably associated with small rectangular enclosures sealed by 0.5m of post Roman deposits as they appear in the sides and across the 80m wide working face of the clay pit.

15.3.51. An enclosure is located at Minors Farm in Minors Lane, Pilning (6162) and is identified in the SGHER as being of Roman date.

15.3.52. Roman occupation to the south of Minors Farm was indicated by a ditch (15816) recorded in 1982 at Monks Lane, Crook’s Marsh, Pilning (Ref. 15-19). It is probably part of the wider Roman Settlement (SGHER 4896, (Ref. 15-20) recorded in the area. This wider settlement evidence is represented by a shallow feature (15817) possibly of Roman date and a series of ditches (15818) recorded in the edge of a clay pit in 1982. The same settlement is also recorded in the Bristol City HER (BCHER) (3,002m).

15.3.53. A Roman ditch and pit (20199) were revealed during archaeological work in 2012 at the site of the Severnside Energy Recovery Centre, to the west of the Generating Station Site. Roman remains were present in one trench and could be seen survive from within 0.5m of the present ground level. Parallel to, and approximately 4m away from the Roman ditch was a post hole.

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Early Medieval and Medieval (AD410 – 1066)

15.3.54. A manor house of possible early medieval date is indicated from a field named ‘Hasborough’ (12778) on the Tithe map of Henbury (1840), approximately 1km southeast of the Proposed Development Site. The name is of Saxon origin meaning fortified place (probably manor house) of the hazels. It is possible that this field contained a Saxon Manor house although may have belonged to it. Although the field has been partly destroyed by the Motorway (M5) and trial trenched with no results it is possible that the undisturbed part of the field contains the manor (Ref. 15-21).

Medieval & Post-medieval (AD1066 – 1750)

15.3.55. A pit (14321), perhaps originally containing the remains of a sheep and a small quantity of medieval ceramics was recorded at this location within the CCR Site during a watching brief on the installation of the Abson gas pipeline.

15.3.56. A small area of remnant ridge and furrow (17951) is recorded to the east of the Generating Station Site close to the Severn Road.

15.3.57. A possible Farmstead of medieval date (2992) is located approximately 450m north of the Proposed Development Site. The area is bounded by ditches and surrounded by ridge and furrow, possibly indicating the former site of farm building remains, enclosures and a trackway leading northwest, indicating the site of a deserted farm.

15.3.58. A possible enclosure (2994) of medieval date is located just outside of the southern boundary of the Generating Station Site and is visible on aerial photographs. There is a possible enclosure with underlying ridge and furrow. A watching brief carried out on a cable trench on the southern boundary of the Proposed Development Site along Ableton Lane exposed a ditch containing Roman pottery not far from this Site, which may suggest a Roman date for the enclosure.

15.3.59. A farmhouse and farm building which is marked on aerial photographs approximately 600m south of the Proposed Development Site, but is no longer marked on OS maps, is probably medieval in date (5225).

15.3.60. A possible moated site (5320) is located at Vimpennys Farm, Pilning. The farmstead possibly relates to early freehold held by the manor of Compton Greenfield. The farm was demolished to make way for new development in the 1950s.

15.3.61. A fishpond (5797) was once located close to Minors Lane. There are 13th Century references to a fishpond in this area which changed hands between two manors. In the Ashton Court Papers there is a "Fishpond" field name on the tithe award.

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15.3.62. A possible site of a mill (5798) exists in the vicinity at an undefined location. There is mention of a change of ownership of a mill in the 13th Century in the Ashton Court Papers (Denison and Iles 1985). The "old mill of Peter Croc" is said to lie "on the west side of the way which leads to the seawall" (shown on the Almondsbury Tythe Map 1838). In 1577, there is reference to "all tithes of lands and tenants of Cooky's Marsh and 2 sheaves of one croft called the mill" (Denison and Iles 1985). On the Henbury Tithe Award (1839) the field is called "Millmoat".

15.3.63. The remains of a building and small derelict enclosure visible on an aerial photograph suggest the possible site of a farm approximately 300m north of the Generating Station Site (6716) (Ref. 15-22).

15.3.64. Approximately 600m northwest of the Generating Station Site is an irregular, curving, double banked feature (6717) approximately 15-20m wide and 120m long with regular cross banking, which may be medieval but also possibly fairly recent in origin.

15.3.65. Crook’s Marsh Farm (9250) was recorded on the 1st edition OS map, alongside a second farm, forming a group of buildings, possibly of medieval origin. The name was recorded at least as early as 1496 (Ref. 15-23). The farm is also recorded in the BCHER (2046m).

15.3.66. A settlement at Minors farmstead (9251) was depicted on the 1st edition OS map (1880-1882), but its earlier history is obscure. The lane was recorded from at the latest 1690. The structures and deposits at this site may begin in the medieval period, but this is not confirmed at present.

15.3.67. A farm was depicted at Hook Farm, Vimpennys Common, Pilning (9254) on the 1st edition OS map. Only one building of the complex appears to have survived in 1975 (OS Map), but it had disappeared by 1991. An archaeological survey was carried out on the site in 1996. A medieval origin was suggested by the moat around part of the site. Some of the buildings could date as early as the 16th Century (Wessex Archaeology 1996). The physical layout of this site has been established by 1835 with much building work going on between the date of the tithe map and the 1st edition OS map.

15.3.68. Minors Lane (11112) is located immediately south of the Proposed Development Site. This lane and the adjacent secondary rhine was recognised by the archaeological team as a potentially early landscape feature.

15.3.69. The moat at Hook Farm Vimpennys Common, Pilning (12776) is probably medieval in origin.

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15.3.70. Lower Gallows Acre (12780) to the east of the M49 is marked on the Henbury Tithe and the name could indicate the site of a gallows, or that it belonged to a hangman.

15.3.71. The 3rd edition OS map depicts two farms on either side of the end of a road from the interior of the marsh to the coast (12995). The southwestern building and the road were visible as a cropmark in 1991. Both farms were in existence by the date of the 1st edition OS map, when a third building to the east of the southwestern building (probably a third farm lying in a small close) was recorded. The other buildings lie within the area of BCHER (9225).

15.3.72. An irregular enclosure or settlement site (13509) surrounded by rhines may indicate the site of early re-colonisation of the Severn Levels during the medieval period (Ref. 15-21).

15.3.73. Also on the water pipeline route, a farm of post-medieval date (14322) noted on the 1st edition OS map was avoided by the construction of the previous pipelines.

15.3.74. The extent of post medieval settlement at Severn Farm, Vimpenny Common, Pilning (16369) is shown on the 1st edition OS map. The SGHER suggests there was a medieval farmstead on this site. The approximate extent of post medieval settlement at Hook Farm Pilning (16378) is shown on the 1st edition OS map. This site also has medieval origins. The post medieval settlement at Stowick Farn North Pilning is also shown on the 1st edition OS map.

15.3.75. Ridge and Furrow (18998/9) is visible on aerial photographs, as shown in Figure 3-4a (Volume III of this PEI Report).

15.3.76. A possible Post Medieval groyne (19960) is visible as a structure on aerial photographs (1465110). The structure is located on Chittening Warth at New Pill Gout. The structure is defined by a double row of wooden stakes that extend at right angles to the shore and has a total length of 150m and orientated northwest/southeast. The present course of the New Pill follows the line of wooden stakes which may have been constructed to channel the Pill and therefore prevent erosion of the peat layers on the accreting on the foreshore. The structure was visible on aerial photographs taken after 1990 (Ref. 15-24).

15.3.77. A Medieval and/or Post Medieval fish weir is visible on gravel banks (19962) as a wooden structure on aerial photographs (Ref. 15-24). The weir is located on the Gravel Banks south of Severn Beach. The weir is defined by a curving double row of wooden stakes which measures a total length of 230m and orientated northwest/southeast. The weir would form a rank or `hedge’ for the placement of putts or putchers (basket traps). The fish weir was still visible on aerial photographs taken in 1969 as a linear feature in the mud but no wooden posts are visible.

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15.3.78. Worthy Farm (2164M) is recorded in the Feet of Fines for 1241 when the property is named "La Wrthie", approximately 500m south of the Proposed Development Site. The property was recorded by the tithe survey in 1841. It is shown by the 1915 Ordnance Survey map (Gloucestershire sheet LXVII.10) as a farmhouse and complex of farm buildings.

15.3.79. The site of a building (2166M) of possible post-medieval date is shown on the 1915 OS plan of this area (Glos Sheet LXVII.10). The map depicts a building in a narrow enclosure alongside the road. It now lies under an industrial complex. Structures and deposits relating to this building may survive.

15.3.80. A dwelling or farmstead is located on the bank of the River Severn at Chittening Warth (2167M). Human activity began on this site in the eleventh century when the surrounding area was still saltmarsh and occupation continued into the twentieth century.

15.3.81. A building (possibly two adjoining dwellings) (2168M) was depicted at this location in 1830 (Ordnance Survey 1:63360) and 1915 Archaeological deposits relating to these buildings almost certainly survive.

15.3.82. Washingpool Farm (2172M) was a farm was depicted on the 1830 Ordnance Survey map. The range of buildings was recorded in 1915.

15.3.83. The bridge over Stup Pill Rhine at Washingpool Lane (2256M) carries Washingpool Lane across Stup Pill Rhine at Red Spoltt Gout. It is built of stone and has later brick reinforcing of the arches. The parapet is modern.

15.3.84. A cottage and garden (2258M) are recorded at Red Splot (Reed Splatt) Gout. The building was located to the south of Washingpool Lane and was extant by c.1810, being shown on a survey of that date. The building is recorded by the 1841 tithe assessment.

15.3.85. A house on the western side of Severn Road, Chittening (2259M) is recorded by the 1841 tithe survey and is shown on the Ordnance Survey maps of 1881 and 1915.

15.3.86. A sub-rectangular ditched enclosure (2277M) is located to the south of Severn Road, Chittening.

15.3.87. Chittening Farm (2493M) is shown on the tithe survey of 1841, noting that it was owned by Sir John Smyth and occupied by a tenant. Taylor's 1773 map of the area shows the site of Chittening Farm as open fields

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Early Modern & Modern (1750 – present)

15.3.88. A sheep wash located just west of the M48 motorway (6450) lies on top of a structure which appears to be earlier, and mid-19th century pottery and glass was found in cattle disturbances around this site.

15.3.89. A fish trap is located on the foreshore at New Pill Gout Pilning. The remains comprise several short linear groups of stakes in five parallel lines. The fish trap is 2m wide and extends for 30m running along the beach.

15.3.90. A settlement is recorded on the 1st edition OS map in the area of Stowick Farm just outside of the northeast corner of the Generating Station Site (9224). This site was referred to as early as 1287, the name originally being `Stonwyk', perhaps implying the existence of stone buildings at the site at this early date. This site may be more than usually important, as the placename implies involving both the `stone' element, and the early farm name `wic'. Both may imply the existence of very early occupation at this site, similar to that at Redwick and Northwick.

15.3.91. There is a former medieval settlement located at Vimpennys Common (9255) to the north of the Generating Station Site. Before its enclosure, the Common comprised a few hectares of open land, with at least six occupation sites around it. It is medieval in origin, and has since been enclosed and partly built over.

15.3.92. The Imperial Chemical Industry works at Severnside (13954) was established shortly after World War Two (WWII).

15.3.93. To the east of the Generating Station Site is a railway branch (16342) linking the Former Terra Nitrogen and ICI site to the Avonmouth Seven Tunnel Railway. The works dates to shortly after WWII and the railway is presumably of similar date.

15.3.94. A 20th Century wreck (19663) is located 580m north of Stuppill Gout in the Severn Estuary. The wreck is partially submerged in the intertidal muds and measures 19m long north/south and 5m wide east/west. The wreck is still visible on aerial photographs taken in 1969 and was found to be extant during field survey in 1995.

15.3.95. A possible 20th century groyne (19978) is visible as a structure on aerial photographs. The structure is located on Chittening Warth north of Stuppill Gout and centred at location ST 5302 8230. The structure is a row of wooden stakes that extends at a right angle to the shore and has a total length of 180m and orientated northwest/southeast. The structure was visible on aerial photographs taken after 1980.

15.3.96. A barrage balloon anchor point (19088) was recorded on aerial photographs. It may have been removed before the end of WWII.

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15.3.97. The site of a former Military Camp (19089) of modern date was formerly located at the SITA Severnside Energy Recovery Centre, Severn Road. The camp consisted of a small group of ancillary buildings and huts associated with barrage balloon anchor (SGHER 19088) and is noted in Cotswold Archaeology Desk Based Assessment (Ref. 15-24).

15.3.98. A small circular platform, less than 20m in diameter, with a bank around outer lip is recorded in the BCHER (2,098m). The feature is possibly modern and could be a bomb crater of WWII.

15.3.99. Bank Farm (2,163m) lies on the north side of Severn Road; the site of the farm is shown by Taylor's map of the area in 1773 (not illustrated) as an open field. Bank Farm had been built in the western part of the field by the time of the 1841 Henbury tithe map.

15.3.100. The site of a house is recorded at Hallen Marsh (2,184m). The house is recorded by Benjamin Donne's 1769 Map of the 11 miles around Bristol.

15.3.101. An Army Ordnance Department store (3,097m) is located approximately 110m to the north of Washingpool Farm. The store was built in 1918 to serve National Filling Factory No.23 and is recorded by a plan in the National Archives (MUN 4/1753). Another Armament Store (3,231m) depicted on 1920s Air photograph (Ref 24)). The store was linked to the complex of structures associated with the National Filling Factory at Chittening (2750M). A third store (3,231m) lay to the north and east of Washingpool Farm.

Historic Buildings

15.3.102. This subsection provides a summary of information available on the National Heritage List, SGCC and BCC HER’s.

15.3.103. There are no listed buildings within the Proposed Development Site, Other DCO Land, or within 1km of the Generating Station Site.

15.3.104. Between 2km and 5km from the DCO Site, a total of 14 Grade I and 14 II* listed buildings have been identified. There are also 164 Grade II Listed buildings within 5km.

15.3.105. None of the listed buildings are within 2km of the Proposed Development Site. The Grade I and II* buildings are all located to the south of the Proposed Development Site, at either Blaise Castle Hamlet or Kings Weston House (Figure 15-10 (Volume III of this PEI Report)).

15.3.106. Blaise Castle (Grade II* 1208115) and a timber Lodge (Grade II* 1202280) are located approximately 4.5km to the south of the Proposed Development Site. Slightly closer to the Site at Blaise Hamlet there are several Grade I cottages and

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a sundial. All of these are post-medieval in date are located approximately 4km south of the Proposed Development Site (1202260-64, 1207747, 1207760, 1282246/7, 1282285). Grade II* listed buildings at Blasé Hamlet include a Castle Lodge (1202278) and Gateway (1202280), A House (1279500) and Model Diary (1293555).

15.3.107. To the west of Blaise Hamlet at Kings Weston, approximately 4.7km to the south west of the Proposed Development Site, are four Grade I buildings: Kings Weston House (1209729), a Brew house (1209747), a Loggia (1202338) and ‘The Echo’ (1202339). In addition there are two Grade II* buildings, comprising two lodges (1187186) and a Police Station (1187199). Further afield to the east is the Grade II* East Portal of the Severn Tunnel (1409075).

15.3.108. Outside of Blaise Castle Hamlet or Kings Weston House there a further two Grade II* listed buildings. The Church of St Mary The Virgin (1205113) is located to the south of Blaise Hamlet and a gothic arch is located further to the east (1282073).

Historic Maps


15.3.109. The 1799 plan of land in the Hamlet of Crook’s Marsh (1799) Bristol Records Office (BRO) 31965/34 (Map A in Appendix H (Part 3), Volume II of this PEI Report) depicts the site as agricultural fields, subdivided by hedgerows and drainage channels (Rhynes). Minors Lane is apparent and two further trackways extend from the lane across the Generating Station Site towards Crook’s Marsh. A small square enclosure containing a single small rectangular building is located immediately to the north of where Minors Lane enters the Proposed Development Site from the south.

15.3.110. The 1825 Plan of Estates belonging to Edward Simpson (BRO (Sturge) 3165/33) (Map B in Appendix H (Part 3), Volume II of this PEI Report) depicts the building in the southern corner of the Proposed Development Site with a further square building a short distance to the north on the west side of Minors Lane. Perhaps most interestingly though is the written annotation referring to large field in the southeast corner of the Proposed Development Site (immediately to the west of the enclosure containing the small building). This field is referred to as an ‘Old House Ground’. This is particularly important as this field is also the location of the low mound identified by the geophysical survey (see Figure 15-7a (Volume III of this PEI Report)), which may represent a house platform of medieval or late medieval date (Ref. 15-26). Further evidence for this has come from pottery retrieved during a geotechnical monitoring exercise.

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15.3.111. The 1st Edition OS map (Map C in Appendix H (Part 3), Volume II of this PEI Report) presents the two enclosures located along the north side of Minors Lane at least two buildings are present in the eastern of the two enclosures. Both enclosures contain a number of trees on this map. The 1903 OS map or any of the subsequent O.S maps (Maps E-I in Appendix H3, Volume II of this PEI Report) do not show any significant changes to the site.

Other DCO Land

15.3.112. The majority of the pipeline route has been assessed previously through several Desk Assessments (see Appendix H (Part 1), Volume II of this PEI Report). As a result, the assessment has been restricted to inclusion of historic maps from the 1st edition OS maps.

15.3.113. The entire route is depicted on the 1886 OS map (Map 3 in Appendix H (Part 3), Volume II of this PEI Report). This shows the agricultural nature of the landscape at this time. The cooling water pipeline is depicted passing through fields, orchards and close to a number of farms, most notably, Worthy, Chittening and Washingpool Farms towards the northern end of the route and Green Splott Farm further south. During WWI, several buildings in relatively close proximity to the route were in military use including a hospital and various store buildings. These are listed in the baseline text and illustrated on Figure 15-3a and Figure 5-3b (Volume III of this PEI Report). The area along the route remained predominantly agricultural until the 1950’s when the first major industrial buildings appeared. The area became progressively more industrialised up to the present day.


15.4.1. There are no specific avoidance measures that have been implemented in the design of the Proposed Development relevant to archaeology and cultural heritage.

15.4.2. The proposed cooling water pipeline corridor was selected partially based on preliminary archaeological investigations. Given the sensitivity of the area and especially the coastline along the Severn Estuary, it was decided prudent to follow the route of the existing pipelines between Bristol WWTW and Seabank 1 & 2 as far as possible.

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Construction Phase

15.5.1. For ease of reference, the assessment of construction impacts has been split into the main development parcels for the Proposed Development Site and associated infrastructure.

15.5.2. The areas of potential archaeological impact include the peaking plant buildings, turbine buildings, HRSG buildings, generator transformers, water storage tanks, and pump pits for the cooling towers. The location of these structures are shown on Figure 4-1a., (Volume III of this PEI Report).

15.5.3. Only those development parcels where an impact might be experienced are discussed below.


15.5.4. Although the Proposed Development is expected to be constructed upon imported material up to an average 2.2m in depth, construction works for the turbine and HRSG buildings, and cooling water pump pits may include the development of foundations which require limited below-ground excavation resulting in below ground disturbance to potential archaeological remains should they be present. The structures requiring foundations potentially below the existing ground levels is illustrated in Figure 15-11 (for the single-shaft configuration) and Figure 15-12 (for the multi-shaft configuration), in Volume III of this PEI Report.

15.5.5. Any archaeological remains present are likely to date to the Iron Age or Romano British periods but there is also evidence for occupation during the later medieval period with a possible house platform being present in the southern part of the Generating Station Site. The current design suggests that Roman ditch features may be impacted by piling and foundations. The historic significance of any archaeological remains revealed during such ground works is not currently known but is likely to be Medium. Due to the largely raised nature of the development there will be only discrete areas of below ground impact (e.g. pile caps and cooling foundations). Construction works for the main structures are not expected to physically affect the possible house platform feature identified in the geophysical survey, due to its location (see Figure 15-7a, Volume III of this PEI Report). However, it is possible that an underground pipeline will be trenched through this location (the construction technique has not been confirmed and may comprise boring or HDD, or even above ground pipe). If this is confirmed, impact upon buried archaeological remains is likely to occur.

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15.5.6. Given the importance of these features, the potential effect is considered major adverse without appropriate mitigation. Archaeological remains such as ditches or pits can be dealt with through an archaeological watching brief on initial removal of topsoil material however. Although not envisaged, should there be a potential for effects on the potential house platform feature, further information may be required through an evaluation exercise in order to prepare an appropriate mitigation strategy and to assess the potential for impact.

15.5.7. Providing that the ground conditions are still intact following work onsite by third parties developing the Severnside Energy Recovery Centre, new Red Rhine channel, and Spine Access Road (see Chapter 7: Assessment Methodology), an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of potential below ground impact. This may include impacts on the small number of potential ditch locations discussed above as identified by the geophysical survey. Should the evaluation confirm the presence of significant archaeological remains, particularly relating to domestic occupation, an open area excavation may be required to mitigate the effect of the Proposed Development.

CCR Site (Temporary Compound)

15.5.8. The CCR Site will be used for the Contractor Compound, parking during construction, and laydown of materials, as discussed in Chapter 5: Enabling Works and Construction. These activities will initially include topsoil strip, which is expected to penetrate 200mm to 300mm below the existing ground levels and should therefore cause minimal impact to any below ground archaeology. The effect on the CCR Site is therefore considered to be negligible and is not discussed further.

15.5.9. Both evaluation and mitigation works will be detailed in separate Written Schemes of Investigation (WSI) to be agreed by SGC, BCC and English Heritage.

15.5.10. Following mitigation the residual effect is considered minor adverse.

Other DCO Land

15.5.11. Construction works associated with the proposed cooling water pipeline have the potential to impact archaeological remains. However, disturbance of any potential archaeological remains may be somewhat limited as the pipe trench will be located within the nominally 30m wide corridor that constitutes the Other DCO Land and in close proximity to the existing pipelines. It is likely that some of the trench will be excavated through made ground of modern date. However, at some points the trench may be excavated through previously undisturbed ground. Figure 15-13a to Figure 15-13e (Volume III of this PEI Report) illustrate

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the area of the proposed cooling water pipeline corridor that has been previously disturbed.

15.5.12. The trench will be approximately 2m depth and is likely to expose organic deposits relating to the prehistoric occupation of the area that may be of significant archaeological value. Although the trench will be generally 3m wide there will also be a construction corridor nominally 20m wide to allow areas for soil stockpiles, laydown, vehicle access etc. The corridor for the previous pipeline will no doubt have caused significant disturbance. However, where sections of the corridor in undeveloped areas will be stripped of topsoil prior to the trenching works there is the potential for these ground works to disturb archaeological remains.

15.5.13. Based on the baseline information, the importance of the pipeline corridor is considered to be Low. The magnitude of change should a feature be disturbed or destroyed is also considered Low, which would result in a minor adverse effect prior to mitigation.

An archaeological watching brief, in accordance with a Written Scheme of Investigation to be approved by BCC, will be undertaken during initial topsoil strip of sections along the cooling water pipeline in areas not currently occupied by hardstanding. The resulting residual effect is therefore considered to be of negligible significance.

Operational Phase

15.5.14. It is not considered likely that any activities pertaining to the operation or maintenance of the Proposed Development or cooling water pipeline will effect below ground archaeological remains.

15.5.15. The physical appearance of the Proposed Development will affect the setting of two assets listed below. The CCGT stacks will be erected to 90m height above the finished ground level (up to 98.5m AOD) and the peaking plant stacks to 45m above the finished ground level (up to 53.5m AOD). The main buildings onsite are the HRSG buildings which will be up to 45m high (up to 53.5m AOD). The maximum heights and massing of the buildings and structures are presented in more detail in Chapter 4: Project Description.


Assets of Very High or High Value

15.5.16. Blaise Castle and Kings Weston House have been assessed as being of Very High importance.

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15.5.17. The construction of the Proposed Development and associated infrastructure will not directly impact any designated or non-designated built heritage assets within the 5km study area.

15.5.18. There will be a minor adverse visual impacts from the HRSG and turbine buildings and stacks on views from the northeast, from the upper storeys of the Grade II* designated building of Blaise Castle. This is situated on a ridge to the east of the Proposed Development at approximately 88m AOD. There will be clear views of the Proposed Development from the upper floors of the castle which is a late eighteenth century folly. Views from ground level will be restricted by high woodland surrounding the castle. The historic setting of ten Grade I buildings at Blaise Hamlet and four Grade II* structures located further to the southeast will not be affected due to a much lower elevation and screening by vegetation and modern development.

15.5.19. There is therefore considered to be a ‘Minimal’ magnitude of change on Blaise Castle, meaning that there is a change to the asset that hardly affects significance and no real change in the ability to understand and appreciate the resource and its historical context and setting.

15.5.20. Taking into account both the magnitude of change and importance, the residual effect (based on the criteria in Table 15-4) on Blaise Castle is judged to be minor adverse.

15.5.21. Kings Weston House is well screened year round by surrounding vegetation and is therefore be protected from views of the Proposed Development, leading to ‘No Change’ and an effect of negligible significance.

15.5.22. No further assets of very high or high value are anticipated to experience any change as a result of the Proposed Development: The residual effect on all other designated assets is therefore expected to be negligible.

Assets of Medium Value

15.5.23. The following assets are considered to be of Medium value:

• Enclosure Seabank Pucklechurch Pipeline, Almondsbury (14322), within the southern part of the Proposed Development Site; and

• Possible House Platform within site (not currently on HER), illustrated on Figure 15-7a (Volume III of this PEI Report).

15.5.24. These features are situated within the Utilities, Services and Landscaping Area, which is reserved for the realignment of underground utilities and, in this particular location, ruderal vegetation or grassland (see Chapter 4: Project Description). An archaeological evaluation may be required in advance of construction should this part of the pipeline be installed using an open trench,

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which could affect the potential house platform. In addition, a watching brief will be undertaken during construction in these areas, which, because of the localised impact on these widespread features, is anticipated to result in a ‘Minimal’ change of magnitude at these locations. Based on the criteria in Table 15-4, is anticipated to lead to a residual effect of minor adverse significance.

Assets of Low Value

15.5.25. The Ridge and Furrow Cultivation (2) New Pill Gout Chitterling Gout Pilning (18999) asset located within the Generating Station Site is considered of ‘Low’ value, but is expected to experience a ‘High’ magnitude of change due to the Proposed Development. This corresponds with change such that the significance of the asset is totally altered or destroyed, or comprehensive change to setting affecting significance, resulting in changes in our ability to understand and appreciate the resource and its historical context and setting. Based on the criteria presented in Table 15-4, the significance of this effect is considered to be moderate adverse without appropriate mitigation, which is discussed below.

15.5.26. The Series of ditches (14323) within the western part of the Proposed Development Site and Early Peat deposits (17668) approximately 500m northwest of the Site, are considered of ‘Low’ value and, due to the localised impact on this widespread feature, it is considered that it will experience a ‘Minimal’ magnitude of change. According to Table 15-4, the residual effect is considered to be negligible on these assets.

15.5.27. Providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of potential below ground impact. This will add knowledge but will not reduce the permanent removal of the asset and therefore the residual effect is considered minor adverse.

15.5.28. Taking into account the proposed mitigation, the residual effect on the Iron Age/ Roman enclosure and Medieval/Post medieval enclosure within the Proposed Development Site is deemed to be minor adverse. The residual effect on the Roman Field system is also judged to be minor adverse.


15.5.29. There are no assets of Very High, High or Moderate value expected within the construction corridor of the cooling water pipeline or electrical connection. This is known because the route of the pipeline has been previously assessed through desk based assessment (see section 15.1 and Appendix H (Part 1), Volume II of this PEI, Event no’s 20079 and Event no 20080). The watching brief (Event no 20080) did not reveal any archaeological remains although in several areas

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encountered buried land deposits. There are no other archaeological remains expected to be impacted by the cooling water pipeline.

Assets of Low Value

15.5.30. The Buried Land Surface- Neolithic deposit at Smoke Lane (3237M) is considered of ‘Low’ value and is expected to experience a ‘Minimal’ magnitude of change through the installation of the cooling water pipeline, given it is approximately 50m west of the construction corridor. According to Table 15-4, the residual effect is anticipated to be negligible.

15.5.31. Mitigation has been proposed in the form of a programme of archaeological fieldwork during initial topsoil strip of sections along the cooling water pipeline in areas not currently occupied by hardstanding. This will add knowledge but will not reduce the permanent removal of the asset and therefore the residual effect is minor adverse.


15.5.32. It is not expected that the decommissioning phase would have the potential to disturb any below ground archaeological features. The work should not require new, undisturbed areas to be affected, and hence would be expected to lead to ‘No Change’ and an effect of negligible significance.

15.5.33. The removal of the Proposed Development is expected to reverse the minor adverse effect on the setting of Blaise Castle, hence leading to a minor beneficial effect. Any negative effects on setting would arise from cranes or other large mobile plant onsite, which would be temporary and unlikely to create a significant effect on these heritage assets.


Archaeological Effects

Proposed Development Site 15.6.1. The Generating Station Site will be raised by up to an average 2.2m above the

current ground level to a maximum 8.5m AOD. Following the assessment of potential effects, mitigation has been proposed to reduce the localised impacts from foundation construction upon the identified heritage assets.

15.6.2. The assessment has identified the potential for archaeological remains dating from the Prehistoric, Roman and medieval periods to be present within the Proposed Development Site. However, the raising of the ground level within the Generating Station Site suggests that there should be no impact upon these remains.

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15.6.3. The areas of potential archaeological impact include the peaking plant buildings, turbine buildings, HRSG buildings, generator transformers, water storage tanks, and pump pits for the cooling towers, the locations of which are shown on Figure 4-1a,(Volume III of this PEI Report). Based on the depth of archaeological features in this part of the Site, excavations greater than 2.0m below current ground level in these locations could disturb deposits that may retain archaeological remains of Iron Age or Roman date. Horizons of organic deposits containing material of palaeoenvironmental interest may also be located at greater depths. As mentioned above, providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken of these areas prior to issue of the final ES.

15.6.4. There are two scheduled monuments situated on elevated ground within the 5km study area to the east that will be afforded partial views of the Proposed Development. The first is the Scheduled Monument of Blaise Castle approximately 3.5km southeast of the Proposed Development Site at approximately 88m AOD. There is predicted to be a minor adverse effect on the historic setting of this SAM which is defined by a parkland setting.

15.6.5. The historic setting of the Iron Age hill fort at Kings Weston Camp at Henbury will not be compromised due to dense woodland which screens all views to and from the Proposed Development Site, resulting in a negligible effect.

15.6.6. The historic setting of the remaining Scheduled monument of the Anti-Aircraft Battery to the 2.1km to the west and the Mere Bank 3.3km to the west of the Proposed Development Site will not be impacted due to the level nature of the terrain and intervening development. This is also the case for the final SAM within the 5km study area, which are the remains of a minor Romano-British villa at Long Cross 4.8km to the southwest.

Other DCO Land 15.6.7. The proposed cooling water pipeline is intended to run adjacent to the west of the

route of the current cooling water pipelines to and from Seabank 1 & 2. The BCC HER records numerous investigations and a small number of known assets within 1km of the cooling water pipeline. The locations of the archaeological events and monuments is shown on Figure 15-2, Figure 15-3a, and Figure 15-3b (Volume III of this PEI) and detailed in Appendix H (Part 4), Volume II of this PEI.

15.6.8. The construction trench and corridor for the previous pipeline was archaeologically monitored and the proposed pipeline will therefore be located in ground that has been previously disturbed. There is low potential for archaeological remains to exist in residual areas of the proposed nominally 30m wide pipeline corridor for the cooling water pipeline. As mentioned above, topsoil stripping in these areas will be monitored archaeologically at the time of works

May 2014 Page 15-34

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being undertaken. A geoarchaeological specialist will also be commissioned to inspect any profiles revealed that may contain the potential soil horizon of Neolithic date. The geoarchaeologist will take samples where suitable deposits are revealed. The sampling strategy will be agreed with the Regional Science Advisor for English Heritage.

15.6.9. The scheduled monument of Mere Bank (1020664, Figure 15-3 (Volume III of this PEI)) is located approximately 65m to the south of the southern terminus of the proposed cooling water pipeline corridor but will not be directly affected by the construction of the cooling water pipeline.

Built Heritage Effects

15.6.10. The construction of the Proposed Development and associated infrastructure will not directly impact any designated or non-designated built heritage assets within the 5km study area. There will be a minor adverse visual impacts from the cooling towers and stacks on views from the northeast, from the upper storeys of the Grade II* designated building of Blaise Castle. Views from ground level will be restricted by high woodland surrounding the castle. The historic setting of ten Grade I buildings at Blaise Hamlet and four Grade II* structures located further to the southeast will not be affected due to a much lower elevation and screening by vegetation and modern development.

15.6.11. There will be occasional distant views of the Proposed Development from the Registered Park and Garden of Kings Weston House 5km to the southwest. The CCGT stacks will be set against a background of the Severn Estuary which will decrease the potential visual impact. It is therefore considered that the historic setting of Kings Weston Park and the Grade I listed building of Kings Weston House will not be affected. The residual effect on the significance of the setting of Kings Weston Park is therefore considered to be negligible.

15.6.12. Table 15-6 provides a summary of the conclusions of this PEI chapter.

Table 15-6: Summary of Cultural Heritage Residual Effects Asset Name Importance Potential

Impact Nature of Impact

Mitigation Measures Residual Effect

Proposed Development Site Iron Age/Medieval Enclosure 2994 (5)

Medium Physical impact from construction phase

Permanent Trial trenching followed by Excavation and post-excavation analysis

Minor Adverse

Post medieval Enclosure 14322

Medium Physical impact from landscaping proposals

Permanent Watching brief on Landscaping works in this area

Minor Adverse

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Asset Name Importance Potential Impact

Nature of Impact

Mitigation Measures Residual Effect

Roman Field System 14323



Minor Adverse

Ridge and Furrow Cultivation 18999



Minor Adverse

Mound (House Platform?)

Potentially Medium

Possible physical impact from construction phase


Minor Adverse

Blaise Castle Very High Impact on significance of setting

Permanent None Minor Adverse

Kings Weston House

Very High Impact on significance of setting

Permanent None Negligible

Associated Infrastructure Buried Soil Horizon(s) Identified in previous watching brief

Medium Physical impact from construction

Permanent Archaeological Watching Brief in selected areas (Figure 15- 13a-e, Volume III)

Minor Adverse

Heritage Features such as laise Castle and Kings Weston House

Very High Impact on significance of setting

Permanent None Negligible


15.7.1. This section assesses the effect of the Proposed Development and associated infrastructure in combination with the likely effect on archaeology and heritage arising from other developments in the area. It considers development that are either similar in nature or scale to the Proposed Development or within close proximity of it. The schemes outlined in Chapter 7: Assessment Methodology could have a cumulative effect with the Proposed Development and associated infrastructure on archaeology and cultural heritage.

15.7.2. None of the below ground archaeological features that have been identified are likely to be affected by these cumulative schemes. It is also expected that the

May 2014 Page 15-36

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cumulative schemes would implement good industry practice, which involves appropriate desk study, intrusive investigation where required, and archaeological monitoring in liaison with SGC and/or BCC. Where archaeological features are encountered the cumulative schemes are expected to generate a minor adverse effect; because each artefact is geographically distinct and separate, it is not expected that any cumulative effects greater than minor adverse would occur.

15.7.3. Once operational, the cumulative schemes will together lead to a more built up landscape, particularly when viewed from the setting of Blaise Castle and Kings Weston House. Although the stacks and possibly some of the other structures may be visible from these assets, given the general industrial nature of the area already, the recent history of the area being more industrial than now, and the distance of these sites from the heritage assets mentioned, it is not expected to increase the cumulative effect beyond minor adverse.


15.8.1. This section identifies any impacts and effects that have not yet been determined, or changes that are expected between writing this report and submission of the DCO application.

15.8.2. Any changes that lead to differing or new impacts and effects will be highlighted within the final ES, along with the reasons for the change.

15.8.3. It is also likely that the baseline conditions will change between the preparation of this PEI Report and the final ES. The Proposed Development Site is currently subject to excavation, top soil stripping, and levelling in certain areas in order for third parties to deliver the Spine Access Road and new channel for the Red Rhine, which are discussed in Chapter 2: The DCO and EIA Process and Chapter 7: Assessment Methodology. A haul road is also being constructed through the middle of the Proposed Development Site to enable access by third party from the roundabout to the east of the Site to the Severnside Energy Recovery Centre to the west. These works onsite are being undertaken by other developers, under extant planning permissions and are separate to the Proposed Development.

15.8.4. Providing that the ground conditions are still intact following work onsite by the third parties, an archaeological evaluation exercise will be undertaken prior to issue of the final ES within the locations of below ground impact, as previously discussed.

15.8.5. The final ES will report on the baseline conditions considered relevant at the time of submission, or an agreed point of time shortly before, as well as any changed

May 2014 Page 15-37

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to the predicted magnitude of change or effects on archaeology and cultural heritage as a result of the changing baseline conditions.

15.9. References

Ref. 15-1 Department for Communities and Local Government (2012) National Planning Policy Framework

Ref. 15-2 Department for Communities and Local Government (2010). PPS5: Planning for the Historic Environment: Historic Environment Planning Practise Guide

Ref. 15-3 Institute for Archaeologists. (2012). Code of Conduct.

Ref. 15-4 English Heritage (2008) Conservation Principles, Polices and Guidance

Ref. 15-5 English Heritage (2011) The Setting of Heritage Assets

Ref. 15-6 Planning (Listed Buildings and Conservation Areas) Act 1990

Ref. 15-7 Planning and Compulsory Purchase Act 2004

Ref. 15-8 South Gloucestershire County Council (2013) Local Development Framework [Online]

Ref. 15-9 The Town and Country Planning (Environmental Impact Assessment) Regulations 2011

Ref. 15-10 Masser P Jones J McGill B (2005) Romano-British settlement and land-use on the Avommouth Levels

Ref. 15-11 McGill B (2001) Pucklechurch to Seabank Pipe Line Archaeological Programme Volume 2

Ref. 15-12 Everton, A., and Everton, R., 1980. ‘Romano-British occupation at Crook’s Marsh Farm, Avonmouth’, Bristol Archaeological Research Group Review 2, 57–8.

Ref. 15-13 BaRAS 1997. ‘Archaeological Watching Brief on the construction of 132 & 33KVoverhead electricity lines to Seabank Power Station, Hallen, Bristol’ (Bristol and Region Archaeological Services unpublished report, 263/1997, in South Gloucestershire SMR).

Ref. 15-14 BaRAS (1995) Land to the south of the Former Seabank Hydrcarbon Reforming Plant. Archaeological Desk Based Assessment

Ref. 15-15 BaRAS (1998) Seabank to Avonmouth Sewerage Works Pipeline. Archaeological Watching Brief

Ref. 15-16 BaRAS (1999) Seabank to Avonmouth Sewerage Works Pipeline. Archaeological Watching Brief

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Ref. 15-17 Stratascan (2001) Geophysical Survey at Smoke Lane, Rockingham, Avonmouth

Ref. 15-18 Russett, V, J, (1990) Archaeology of the Second Severn Crossing 1b

Ref. 15-19 Masser P Jones J McGill B (2005) Romano-British settlement and land-use on the Avommouth Levels

Ref. 15-20 Everton, A, and Everton, R, (1981) Romano-British Occupation at Crook’s Marsh Farm Avonmouth

Ref. 15-21 Robinson S Marvell A (1997) GGAT Project A 430 Junction G Archaeological Desk- Based Assessment

Ref. 15-22 McDonnel, R, (1989) Avon Levels Survey

Ref. 15-23 Smith A H (ed) (1964) Place names of Gloucestershire

Ref. 15-24 Aerial Photograph (CCC 11756/6238 ST 5279/1)

Ref. 15-25 Cotswold Archaeology, (2009) Land at Avonmouth Cultural Heritage Desk Based Assessment

Ref 15-26 Locock, M., and Lawler, M., 2000. ‘Moated enclosures on the North Avon Level: survey and excavation atRockingham Farm, Avonmouth, 1993–7’, Trans. B.G.A.S. 118, 93–122.

Ref 15-27 McGill, B., 2001. ‘Pucklechurch to Seabank Pipeline: Archaeological Programme, vols. 2 and 3’ (McGill Archaeological Consultants unpublished report in South Gloucestershire SMR).

Ref 15-28 Carter, SP, Jones, J and McGill, B 2003 Pucklechurch to Seabank pipeline: sediment stratigraphic and palaeoenvironmental data from the Avonmouth Levels. Archaeology in the Severn Estuary, 14, 69-86

May 2014 Page 15-39

Seabank 3 PEI Report – Chapter 16 Ecology

May 2014 Page 16-1

16. Ecology

16.1. Introduction

16.1.1. This chapter of the PEI Report addresses the potential ecological effects

predicted to arise as a consequence of the Proposed Development and


16.1.2. This chapter describes the baseline conditions at the DCO Site and surrounding

area; potential direct, indirect and induced effects during the construction,

operational and decommissioning phases of the Proposed Development and

associated infrastructure; and any measures to avoid or mitigate predicted

adverse effects of the Proposed Development and associated infrastructure on

ecological receptors.

Consultation


to allow stakeholders the opportunity to comment on the proposed structure, EIA

methodology and content of this PEI Report and subsequent ES. A summary of

stakeholder comments relevant to this chapter is provided in Table 16-1.


Stakeholder Comment Response

Planning Inspectorate The potential impacts on internationally and nationally designated sites should be addressed as well as county level habitats and a number of locally designated sites

The range of statutory and non-statutory designated sites that have been considered are presented in Tables 16-6 and 16-7. The potential effects are assessed in section 16.5.

The ecology assessment should take account of the impacts on noise, vibration, air quality and water quality and cross reference should be made to the relevant technical chapters/appendices of the ES.

The assessment takes account of these other topics in section 16.5 and cross references to the relevant chapters.

Countryside Council for Wales (CCW)

The applicant will need to take the Severn Estuary international designations into account when assessing possible impacts from the proposal in the EIA. There are a number of other nationally and internationally important sites within 10km of the proposed sites, such as River Wye SAC, SSSI which is connected hydrologically to the Severn Estuary.

The potential effects on these international designations are addressed in the Habitats regulations Assessment, which is presented in Appendix K Part 1, Volume II of this PEI Report. The effects are also summarised in section 16.5.


May 2014 Page 16-2


It is unclear if the 16 statutory sites found within 10km of the site include those in wales

The statutory sites include those in Wales and this is included in Appendix K Part 8, Volume II of this PEI Report.

The ES should contain sufficient information to allow all the Habitat Regulations Assessments to be carried out, including any appropriate assessments should they be required.

This is addressed within HRA screening report, Appendix K Part 1, Volume II of this PEI Report.

Marine Management Organisation

If direct cooling using water from the estuary is utilised, marine environmental impacts will need to be taken into account.

This option has since been discarded and therefore the consultation response is not addressed further in the PEI Report.

BCC The proposed electrical connection and its study corridor directly impacts on a Wildlife Network Site (WNS), Crook’s Marsh. Accordingly this area should be surveyed using extended phase 1 methodology.

The electrical connection has been modified since scoping so that it extends through or under the Seabank 1 & 2 site. This is discussed in section 16.3.

The proposed water pipeline has the potential to directly affect a number of Sites of Nature Conservation Importance (SNCIs) and WNS - this area should be surveyed using phase 1 methodology at the appropriate time of year and a method statement developed to minimise the impacts.

Baseline surveys of the cooling water pipeline are still being undertaken. Data collected at the time of preparation of the PEI Report is presented in section 16.5 under the heading ‘Other DCO land’. The assessment for the cooling water pipeline will be completed following completion of the surveys and reported in the final ES

The ecological chapter of the ES will need to include not only an extended phase 1 habitat survey of the land in question but also regularly repeated field surveys of the use of the fields by birds, especially wading birds and waterfowl which are qualifying interest feature birds of the Severn Estuary European Marine Sites.

The scope of surveys for wintering birds was discussed and agreed with Natural England. The methods are presented in section 16.3, and results in section 16.5 and Appendix K Part 4, Volume II.

NE It should be noted that the ponds at Bristol Waste Water Treatment Works are designated a SNCI.

This site is included in the scope of the assessment and details of it are presented in Appendix K Part 1, Volume II of this PEI Report. The assessment of any effects of the development will be presented in the final ES.


May 2014 Page 16-3


The ES should consider the potential for birds to hit the overhead wires if overhead lines are installed.

Overhead lines are not part of the Proposed Development, as explained in Chapter 4: Project Description.

A habitat survey (equivalent to Phase 2) should be carried out across the development area. In addition, ornithological, botanical and invertebrate surveys should be carried out at appropriate times of the year, to establish whether any scarce or priority species are present.

Statutory consultees, including Natural England, Bristol City Council and South Gloucestershire Council were consulted on the scope of the surveys. Methods and timing of surveys is presented in sections 16.3 and 16.5.

It is important to consider the seasonal impacts of the development and avoid any noisy or disruptive activities in sensitive areas, for example laying pipes in winter months across known wintering bird habitat.

The potential for seasonal impacts is discussed for the Proposed Development site in sections 16.5. Appropriate control measures are presented in section 16.5. Effects arising from the cooling water pipeline will be more fully assessed in the final ES.

SGC It is considered important that the EIA takes account of the Cresswell report that included a review of the partially implemented historic ICI planning permission - 'the 57/58 consent'. Provided the proposed CCGT proposal accords with the strategy for new wetland habitat contained within the Cresswell report, there should be no significant effect on the Severn Estuary European Site (SPA/Ramsar).

The recommendations from the Cresswell report have been considered and used as the basis for specific mitigation measures proposed for the Proposed Development in section 16.5.

Other potential impacts on the ecological receptors or conservation objectives of the Severn Estuary SAC/SPA/Ramsar - such as noise, vibration, traffic, dust, lights or aerial or aquatic discharges - may need to be subject to their own HRA or Appropriate Assessment under the Habitat Regulations 2010.

These impacts are discussed in section 16.5 and the HRA Screening assessment presented in Appendix K Part 1, Volume II of this PEI Report.

EA Full consideration should be given to the Eels Regulations (2009) to ensure safe passage when proposing mitigation measures.

The requirements of the Eel Regulations (2009) is summarised in Appendix D, Volume II of this PEI Report. The occurrence of eels in Red Rhine is described in section 16.3.


May 2014 Page 16-4


The Red Rhine may also support water voles and act as corridors for otter. As such, proposed survey work in the Spring should highlight any potential impacts on these species.

Surveys for water vole are in progress. An assessment of the impacts of the scheme on these receptors will be presented in the full ES.

Legislation and Planning Policy

16.1.4. An overview of planning policy relevant to this chapter is presented in Appendix

D, Volume II of this PEI Report. A summary of relevant legislation that has been

considered in this assessment is provided below:

• Birds Directive 2009/147/EC - prohibits activities that directly threaten

certain birds.

• The Conservation of Habitats and Species Regulations 2010 - projects

can only be permitted having ascertained that there will be no adverse

effect on the integrity of 'European sites'. Projects with predicted adverse

changes on European sites may still be permitted if there are no

alternatives to them and there are Imperative Reasons of Overriding

Public Interest (IROPI) as to why they should go ahead.

• The Wildlife and Countryside Act 1981 – makes it an offence (with

exception to species listed in Schedule 2) to intentionally:

o Kill, injure, or take any wild bird;

o Take, damage or destroy the nest of any wild bird while that nest

is in use or being built; or

o Take or destroy an egg of any wild bird.

The Act also makes it an offence (subject to exceptions) to intentionally

kill, injure or take any wild animal listed on Schedule 5, and prohibits

interference with places used for shelter or protection, or intentionally

disturbing animals occupying such places. Species included in Schedule

5 are:

o Great crested newt (Triturus cristatus)

o Water Vole (Arvicola amphibius)

o Badger (Meles meles)

o Slow worm (Anguis fragilis)

o Grass snake (Natrix natrix)


May 2014 Page 16-5

• The Countryside and Rights of Way Act 2000 (CRoW) - amends the

species provisions of the Wildlife and Countryside Act 1981,

strengthening the legal protection for threatened species.

• Protection of Badgers Act 1992 - makes it an offence, except as

permitted by or under this Act, to wilfully kill, injure or take, or attempt to

kill, injure or take, a badger.

• Hedgerow Regulations 1997 - It is against the law to remove ‘important’

hedgerows without permission.

• Natural Environment and Rural Communities Act 2006 lists for England

(NERC Act Section 41) - lists species and habitats of principal

importance for nature conservation. The list of Species of Principle

Importance describes the biological resources of the UK at a national

level.


Scope of Ecological Impact Assessment

16.2.1. The methodology and assessment broadly follows guidance published by the

Chartered Institute of Ecology and Environmental Management (CIEEM) (Ref.

16-1).

16.2.2. The spatial scope of the assessment includes all ecological receptors with

potential to be directly or indirectly affected by the Proposed Development, and

associated infrastructure, including:

• Statutory sites designated for nature conservation value within 10km and

non-statutory sites within 1km of the Proposed Development Site and

Other DCO land (the desk study for the Proposed Development Site was

undertaken to a distance of 1.5km from the centre of the Site); and

• Legally protected or otherwise notable species currently onsite or

considered likely to be affected by works onsite. For the Other DCO

Land, the surveys incorporated 100m wide corridor, which included the

30m proposed cooling water pipeline corridor plus an additional 35m

either side. This was considered a reasonable buffer based on the

habitats found to be present and receptor sensitivity.

16.2.3. The temporal scope of the assessment is based on the programme described in

Chapter 5: Enabling Works and Construction, in which the assumed start date for

the enabling works has been assumed to be 2017 with the Proposed

Development assumed to become operational in 2021. The predicted ecological


May 2014 Page 16-6

baseline conditions at the start of construction are described in paragraphs

16.3.64 to 16.3.74 and evaluated in Table 16-7.

16.2.4. An Extended Phase 1 habitat survey was undertaken to map all broad habitats

on the Proposed Development Site to record dominant and frequent plant

species, and to assess potential for protected species. A habitat survey has been

carried out along the proposed cooling water pipeline corridor to identify which

protected species surveys are required; the Extended Phase 1 habitat survey for

the pipeline corridor was undertaken during spring 2014 and is presented in

Appendix K Part 9, Volume II of this PEI Report.

16.2.5. As a result of the initial surveys, the following protected species surveys were

conducted on both the Proposed Development Site and Other DCO Land

(excluding the proposed electrical connection corridor which is routed through the

existing Seabank 1 & 2 station):

• Breeding birds;

• Non-breeding birds;

• Bat roost;

• Bat activity;

• Badger;

• Water vole;

• Otter;

• Reptiles;

• Great crested newt; and

• Invertebrates.

16.2.6. It should be noted the scope of the wintering bid survey was based on a

preliminary project design that considered the possibility of installing a cooling

water pipeline into the estuary (which was later discarded); hence it led to a

greater survey area than was required for the Proposed Development, including

surveys of the Severn estuary foreshore in order to allow for the assessment of

any impacts on wintering bird populations for which the site is designated as a

SPA. The selection of hybrid cooling removed the need for shoreline works and is

discussed in more detail in Chapter 6: Project Alternatives of this PEI Report.

Desk Study

16.2.7. Existing data regarding designated sites and protected or otherwise notable

species within 1km of the site boundary were obtained from NE’s Nature on the


May 2014 Page 16-7

map website, the Multi-agency Geographic Information for the Countryside

(MAGIC) website and the Bristol Regional Environmental Records Centre

(BRERC). This search radius was extended to 10km for statutory designated

sites in line with EA criteria for assessment of power station projects with

potential for emissions to air or water, and in line with consultation responses

from CCW.

16.2.8. Owing to the presence of the Severn Estuary SPA and Ramsar site 400m west of

the Proposed Development Site, British Trust for Ornithology (BTO) Wetland Bird

Survey (WeBS) core count and low tide data were also requested.

Field Survey Methods

Extended Phase 1 Habitat survey

16.2.9. An Extended Phase 1 habitat survey was conducted on 24 April 2012, using the

standard Phase 1 methodology devised by the Joint Nature Conservation

Committee (Ref. 16-2) to map the broad habitats present within the Proposed

Development Site.

16.2.10. The survey was extended according to the methodology described by the

Institute of Environmental Assessment (Ref. 16-3) to include targeted searches

for signs of protected species.

16.2.11. Target notes were made to provide supplementary information on species

composition, topography and evidence of management. Notes were also taken of

any evidence of the presence of protected or notable fauna (Ref. 16-4). The

methodology and results of the survey are reported in full in Appendix K Part 2,


16.2.12. The findings of the 2012 survey were verified in subsequent surveys during 2013.

16.2.13. A full extended Phase 1 survey of the Other DCO Land was undertaken during

spring 2014, as presented in Appendix K Part 9, Volume II of this PEI Report.

This survey has identified the presence or possibility of protected and notable

species, requiring further survey, and the findings of these surveys will be

included in the final ES. It has been concluded that as the electrical connection

for the DCO application will comprise underground cables or a low rise cable rack

across land already developed for Seabank 1 & 2, then this will not require

ecological scoping.

Species Surveys

16.2.14. The survey methods utilised for each of the species surveys undertaken are

summarised below and described in full in the relevant technical reports, in

Appendix K Parts 3 to 7, Volume II of this PEI Report. The reports are as follows:


May 2014 Page 16-8

• Appendix K Part 2: Phase I Habitat Survey for the Proposed

Development Site;

• Appendix K Part 3: Bat Surveys;

• Appendix K Part 4: Wintering Bird Surveys;

• Appendix K Part 5: Breeding Bird Surveys;

• Appendix K Part 6: Amphibian Surveys;

• Appendix K Part 7: Reptile Surveys.

16.2.15. These survey reports all cover the Proposed Development Site, but omit the

Other DCO Land. The need for the surveys to be extended to include the Other

DCO Land will be confirmed following the Extended Phase I Habitat Survey;

where it is considered necessary based on current information, the intention to

carry out the surveys is highlighted in the relevant sections later in this chapter.

Bats

16.2.16. A tree bat roost potential survey was undertaken on the three suitable trees

within the Proposed Development Site. Trees were surveyed for the presence or

potential for roosting bats by inspecting the trees for signs of bat occupancy,

such as presence, droppings, scratch marks, staining and feeding remains.

16.2.17. No trees with potential to support roosting bats occur within the Other DCO Land

and therefore roost surveys were scoped out for this part of the DCO Site.

16.2.18. Five evening bat activity surveys and four dawn surveys were undertaken to

identify habitat usage and species composition on both the Proposed

Development Site and Other DCO Land. The surveys followed repeatable set

transects and standard protocol for recording individual bat species and covered

the peak of dusk and dawn bat activity. Heterodyne and frequency division

detectors were used. Sound analysis was also used to further analyse

recordings.

Breeding Birds

16.2.19. Breeding birds were assessed over the course of three survey visits that covered

both the Proposed Development Site and Other DCO Land during the peak bird

breeding season (March to June) in 2013. Given the size of the DCO Site, each

full site visit was split over two separate days.

16.2.20. Surveys followed the standard British Trust for Ornithology Breeding Bird Survey

method (Ref. 16-5). A survey route was taken that allowed observation of all

major areas of habitat within the proposed areas of activity, and the surrounding

habitats.


May 2014 Page 16-9

Non-breeding Birds

16.2.21. Bird surveys initially included the Proposed Development Site and the Severn

Estuary, since the preliminary project design considered including a cooling water

pipeline extending into the estuary; this option was subsequently discarded in

favour of hybrid cooling using water from Bristol WWTW. To record non-breeding

birds, visits were made between October 2012 and March 2013 and again from

August 2013 to October 2013 inclusive. The scope of the surveys was discussed

and agreed in advance with NE, SGC and BCC. Surveys were designed to

record birds at different tidal states, during day and night, and neap and spring

cycles.

16.2.22. On each visit to the Proposed Development Site, the surveyor positioned

themselves at a vantage point and observed birds using appropriate equipment

from this fixed position for the hour up to high or low tide. During the second hour

of survey, the surveyor slowly walked the survey area, keeping toward the

perimeters, primarily to flush cryptically patterned or stationary birds that might

escape detection during the first hour of survey.

16.2.23. For estuary counts, the surveyor was positioned at a fixed point for the daytime

surveys. During nocturnal surveys, the same approach was undertaken as for

inland surveys, namely a first hour of fixed point surveying, followed by an

attempt to walk a transect toward more distant species.

16.2.24. The surveys were undertaken in a range of weather conditions in order to

determine the usage of the survey area in relation to factors such as strong winds

and snow that might affect local distribution of any birds that could potentially use

the estuary and or Proposed Development Site.

Reptiles

16.2.25. To record reptiles, eighty artificial refugia were placed in appropriate locations

across the Proposed Development Site. A total of seven visits were undertaken

between May and October 2013 where all artificial refugia were checked for

basking or sheltering reptiles under suitable temperature and weather conditions.

Hand searches for reptiles were also undertaken including searching beneath

debris already occurring on Site.

Great Crested Newts

16.2.26. Amphibian surveys were undertaken on the Proposed Development Site between

May and June 2013. Four water bodies were surveyed, by a range of methods:

placement of 160 bottle traps, torchlight surveys, and egg searches. Where

possible, for all amphibians identified during the survey the frequency, sex, and

life stage were recorded.


May 2014 Page 16-10

16.2.27. Amphibian surveys of the cooling pipeline route within the Other DCO Land

commenced in May 2013 but could not be completed within the 2013 survey

season. They will be completed in April 2014 and included in the final ES.

Terrestrial and Aquatic Invertebrates

16.2.28. Terrestrial and aquatic invertebrate surveys were undertaken in suitable habitats

on the Proposed Development Site.

16.2.29. An initial scoping survey was carried out along the proposed cooling water

pipeline corridor. As a result, eight areas were chosen for further surveys since

they had potential to support invertebrates of conservation importance.

16.2.30. A variety of terrestrial invertebrates survey techniques were undertaken including

beating, sweep netting, vacuum sampling, splash sampling and light trapping.

16.2.31. Aquatic invertebrates were surveyed by using hand searching, pitfall trapping and

visual searching. A total of eighteen site visits were undertaken between May –

October 2013. Further analysis of samples will be reported in the final ES.


Value of Resource / Receptor

16.2.32. An ecological resource / receptor is defined as a site / area / species of nature

conservation value. Each site / area may have more than one feature of value

that it supports (for example different habitats or populations and/or assemblages

of species). Individual ecological resources / receptors and the features that

comprise them are evaluated according to generally accepted criteria, including

designation and protection status. With reference to published Institute of

Ecology and Environmental Management (IEEM) guidelines (Ref. 16-1) to attain

each level of value / importance, an ecological resource / receptor or one of the

features should meet the criteria set out in Table 16-2 below.

16.2.33. In some cases, professional judgement may be applied to increase or decrease

the allocation of specific value. This judgement is based on consideration of the

following additional criteria:

• Population trends;

• Sustainability of resource / receptor;

• Representativeness;

• Potential for substitution/re-creation;

• Position in the ecological unit;


May 2014 Page 16-11

• Biodiversity; and

• Intrinsic value to stakeholders.

Table 16-2: Valuation of Ecological Receptors

Sensitivity of Receptor Example Criteria

Very High

(international)

An internationally designated site or candidate/proposed site i.e. SPA, proposed SPA (pSPA), SAC, candidate SAC (cSAC) and/or Ramsar site.

A large area of a habitat listed in Annex I of the Habitats Directive or smaller areas of such habitat which are essential to maintain the viability of the larger whole.

Large population of an internationally important species or site supporting such a species (or supplying a critical element of their habitat requirement) ;

UK Red data book species that is listed as occurring in 15 or fewer 10km squares in the UK, that is of unfavourable conservation concern in Europe or of uncertain conservation status or global conservation concern in the NERC species lists; or

Species listed on Annex IV of the Habitats Directive.

High

(National)

A nationally designated site i.e. SSSI or National Nature Reserve (NNR) or a discrete area which meets the selection criteria for national designation (e.g. SSSI selection criteria).

An area of a priority habitat identified in Section 41 of the Natural Environment and Rural Communities (NERC) Act 2006 which constitutes a significant proportion of the UK resource of that habitat (or smaller areas of such habitat, which are essential to maintain the viability of the whole).

Populations of a nationally important species or site supporting such a species (or supplying a critical element of their habitat requirement) which constitutes more than 1% of the national population of that species i.e.: Species listed on Schedules 5 and 8 of the WCA (1981); Other UK Red Data Book species; Other species listed as occurring in 15 or fewer 10km squares in the UK; or Sites supporting 1% or more of a national population of a species.

Medium

(County)

Local Nature Reserves, Sites of Importance for Nature Conservation (SINCs).

A viable area of habitat identified in the County Biodiversity Action Plan (BAP).

Substantial populations of the following species:

Species listed in a County/Metropolitan ‘red data book’ or Section 41 of the NERC Act 2006 on account of its rarity/localisation in a county context; or

Sites supporting 1% or more of a county population.

Low

(Borough)

Viable areas of habitat identified in Section 41 of the NERC Act 2006 but which are not large enough to meet the criteria for national or county value.

Sites/features which are scarce within the Borough or which appreciably enrich the Borough habitat resource.


May 2014 Page 16-12

Sensitivity of Receptor Example Criteria

Small but sustainable populations of a legally protected species or one that is notable for some other reason, e.g. that it is featured in a county BAP or the NERC species lists.

Sites/populations, which appreciably enrich the District/Borough habitat resource (e.g. moderately species-rich hedgerows).

Very Low Less than Low value, or with negligible ecological value.

16.2.34. It should be recognised that even though a site may have no apparent ecological

features, it may perform an ecological function. For example, a site may act as a

‘stepping stone’ with the surrounding landscape.

16.2.35. Protected species are assessed independently of legal protection. For example,

a site which has bat species foraging above it is not automatically of international

value (and therefore analogous with a SAC). Instead, such a site may be

assessed as having value in a Borough or County context.

Magnitude of Change

16.2.36. Magnitude of change results from any factor which may result in a change to the

existing nature conservation resource / receptor. The criteria utilised to

determine the magnitude of impact are identified in Table 16-3. These criteria are

informed by the IEEM (Ref. 16-1) guidelines and have been developed in house

by experienced ecologists and EIA specialists.

Table 16-3: Magnitude of Change

Magnitude of Change

Description

Very High

Landtake of a habitat or feature, if it occurs, may be greater than 30%. Where changes are indirect, disruption of ecosystem functioning occurs, with loss of species and loss of diversity. Changes may be long-lasting or permanent, particularly if loss or major alteration of wildlife habitat occurs. Recovery, if possible, is likely to take more than three years.

High

Landtake of a habitat or feature, if it occurs, may be greater than 20%. Where changes are indirect, disruption of ecosystem functioning occurs, with loss of species and loss of diversity. Changes may be long-lasting or permanent, particularly if loss or major alteration of wildlife habitat occurs. Recovery, if possible, is likely to take more than three years.

Medium

Landtake of a habitat or feature, if it occurs is less than 20% of the area. Where changes are indirect, qualitative change occurs. The abundance of some of the more sensitive species may be reduced. Changes in habitat may be longer lasting. Change is reversible, or nearly so, although recovery of changes other than landtake may take up to three years following cessation of factors causing change.

Low Landtake of a habitat or feature, if it occurs, affects less than 5% of the area. Where indirect changes occur, some changes in species abundance may occur, but the change is reversible. Full recovery is likely in the short


May 2014 Page 16-13

Magnitude of Change

Description

term, probably within a year, following the cessation of factors causing change.

Very Low/ Negligible

With ecological resources / receptors it is often not possible to state categorically that there will be no change, but this category is used when the chance of any change is very low and if it occurs it is well below the level of detection.


16.2.37. Taking the value of each resource / receptor and magnitude of change into

account, these criteria can be combined to produce an overall evaluation of

whether an effect is significant. This is indicated in Table 16-4 below.

16.2.38. An ecological effect results from a change upon a resource / receptor. Direct

effects on resources / receptors resulting from activities that are an integral part

of the Proposed Development have been considered in this ecological

assessment. In addition, indirect, secondary and cumulative effects have been

examined. The duration of the effect (i.e. permanent or temporary and short,

medium or long-term) and sensitivity of a resource / receptor (to a specific effect)

have also been taken into account.

Table 16-4: Classification of Effects

Sensitivity of receptor

Magnitude of Change

Very High

High Medium Low Very

Low/Negligible

Very High Major Major /

Moderate Moderate

Moderate / Minor

Minor

High Major /

Moderate Moderate

Moderate / Minor

Minor Minor /

Negligible

Medium Moderate Moderate

/ Minor Minor

Minor / Negligible

Negligible

Low Moderate

/ Minor Minor

Minor / Negligible


Very Low Minor Minor /

Negligible Negligible Negligible Negligible

16.2.39. Where necessary professional judgement has been applied to the standard

outputs of the decision matrix (as shown in Table 16-4) in order to ensure the

resultant overall effect is considered consistent with the definitions provided in

Table 16-5.


May 2014 Page 16-14

Table 16-5: Definitions of Effects

Classification of Effect Description

Major An effect which in isolation could have material influence on the decision making process and is clearly significant.

Major/Moderate An effect which could have some material influence but requires professional judgement to determine this, and which is significant.

Moderate An effect which on its own could have some influence on decision making, particularly when combined with other similar effects, and which may be considered significant.

Moderate/Minor An effect which may be likely to have some influence on decision making, professional judgement required to determine.

Minor An effect which on its own is likely to have a minor influence on decision making but when combined with other effects could have a more material influence

Minor/Negligible

An effect which could have either a minor or negligible effect which requires professional judgement to differentiate

Negligible An effect that is likely to have a negligible influence, irrespective of other effects

16.2.40. Significant effects occur where valuable or sensitive resources, or numerous

receptors, are subject to changes of considerable magnitude. Effects are unlikely

to be significant where low value or non-sensitive resources, or a small number

of receptors, are subject to minor changes.

16.2.41. Major, moderate/major, or moderate effects are regarded as significant. Where

significant effects occur, the scale of the effect is also considered on a

geographical scale (i.e. International, National, Regional, County, Borough or

Local).

Level of Confidence in Predictions

16.2.42. IEEM (Ref. 16-1) also recommends consideration of the likelihood that a

change/activity would occur as predicted and the degree of confidence in the

assessment of the change on ecological structure and function. A four point scale

as recommended by IEEM is adopted for use in this ES:

• Certain/near-certain: probability estimated at 95% or higher;

• Probable: probability estimated above 50% but below 95%;

• Unlikely: probability estimated above 5% but below 50%; and

• Extremely unlikely: probability estimated at less than 5%.


May 2014 Page 16-15


16.2.43. The proposed envelope (‘Rochdale Envelope’) parameters outlined in Chapter 4:

Project Description do not significantly affect the input parameters utilised in

either the operational or construction ecology assessments, and consequentially

the outcome of these assessments will not vary. Therefore the assessment

adopts conservative (worst case) values where assumptions are necessary.

16.2.44. Regarding the main building sizes, it is assumed that all vegetation within the

main works area will be cleared to facilitate construction, therefore from an

ecological perspective there is not considered to be a difference in the impact

depending on the final sizing and layout of buildings.


16.3.1. A summary of the results of the desk study and field surveys undertaken to

establish the baseline conditions for the Proposed Development Site and Other

DCO Land is presented in this section. Full details of the desk study and field

surveys are presented in the following appendices:

• Appendix K Part 2: Phase I Habitat Survey for the Proposed

Development Site;

• Appendix K Part 3: Bat Surveys;

• Appendix K Part 4: Wintering Bird Surveys;

• Appendix K Part 5: Breeding Bird Surveys;

• Appendix K Part 6: Amphibian Surveys; and

• Appendix K Part 7: Reptile Surveys.

Statutory Designated Sites for Nature Conservation

16.3.2. Figure 16-1, Volume III of this PEI Report illustrates the designated sites that lie

within 10km of the Proposed Development Site.

16.3.3. No statutory designated sites for nature conservation occur within or directly

adjacent to the Proposed Development Site. The nearest statutory designated

site is the Severn Estuary which is situated approximately 400m west of the Site.

16.3.4. There are twenty-eight statutory designated sites for nature conservation within

10km of the Proposed Development Site / DCO Site. There is one Ramsar site,

two SACs, one SPA, seventeen SSSIs, one NNR and seven Local Nature

Reserves (LNR). Some sites have been given multiple designations of which

there are three additional SSSI’s and one SAC. The reasons for their designation

and locations relative to site are detailed in Appendix K Part 8, Volume II.


May 2014 Page 16-16

16.3.5. There are no proposed SACs (pSACs) or Marine Conservation Areas within the

study area.

Non-Statutory Designated Sites for Nature Conservation

16.3.6. Figure 16-2, Volume III of this PEI Report illustrates the non-statutory wildlife

sites located within 1km of the Proposed Development Site and associated

infrastructure.

16.3.7. There are fourteen non statutory designated sites for nature conservation within

1km of the DCO Site. All of which are designated as Sites of Nature

Conservation Importance (SNCI) and two of which are also designated as Avon

Wildlife Trust Site (AWTS). The reasons for their designation and locations

relative to site are detailed in Appendix K Part 8, Volume II.

Protected and Notable Species Records

16.3.8. Records of protected and/or otherwise notable fauna and flora species recorded

within 1.5km of the centre of the Proposed Development Site are presented in full

in the extended Phase 1 habitat survey report (Appendix K Part 2, Volume II).

The information is summarised below.

16.3.9. The only protected species record on the DCO Site was one record of Marsh-

mallow (Althaea officinalis) which was found to occur within the Other DCO Land,

within the proposed cooling water pipeline corridor.

16.3.10. A number of water vole (Arvicola terrestris) recordings have occurred within

Crook’s Marsh and the Red Rhine, less than 1.5km from the centre of the

Proposed Development Site, and 1km from the associated infrastructure.

16.3.11. There are a number of records of badger (Meles meles) within 1km of the Site

boundary, the nearest of which was 820m from the centre from the Proposed

Development Site and 200m from the associated infrastructure.

16.3.12. Protected bird species have been recorded within 1.5km of the centre of the

Proposed Development Site, including kingfisher (Alcedo atthis), and peregrine

(Falco peregrinus). Bird species of conservation concern have been recorded

within approximately 1km of the DCO Site, including Skylark (Alauda arvensis),

Common kingfisher (Alcedo althis), Pintail (Anas acuta), House sparrow (Passer

domesticus), Tree sparrow (Passer montanus), common Starling (Sturnus

vulgaris) and Dunnock (Prunella modularis).

16.3.13. There are several records of butterflies and moths, which are notable species

within 1.5km of the centre of the Proposed Development Site. These include

Small heath (Coenonympha pamphilus), White-letter hairstreak (Satyrium w-


May 2014 Page 16-17

album), Cinnabar (Tyria jacobaeae); Rosy rustic (Hydraecia micacea), Latticed

heath (Chiasmia clathrata); and Blood-vein (Timandra comae). The Moss Carder-

bee (Bombus (Thoracombus) muscorum) has also been recorded within the

study area.

16.3.14. Several other notable invertebrate species have also been recorded within the

study area, mainly associated with the aquatic habitats, for example several

species of water beetle. A total of 3 invertebrate species have been recorded

within 1km of the proposed cooling water pipeline corridor, including a micro-

moth (Agonopterix arenella), a fly (Anagnota bicolor) and mouse moth

(Amphipyra tragopoginis) listed under the NERC S41.

16.3.15. Five notable plant species have been recorded within 1km of the Proposed

Development Site and proposed cooling water pipeline corridor. Sneezewort

(Achillea ptarmica) and Pyramidal orchid (Anacamptis pyramidalis) are listed

under the International Union for Conservation of Nature (IUCN) red list. Marsh-

mallow (Althaea officinalis) and Smooth Rupture-wort (Herniaria glabra) are

classified as rare species and Three-lobed Water-crowfoot (Ranunculus

tripartitus) is listed under Section 41 of NERC, and classified as endangered.

16.3.16. Records of amphibians and reptiles occur from within 1.5km of the centre of the

Proposed Development Site, including great-crested newt, grass snake and slow-

worm. No records of amphibians and reptiles have been recorded within 1km of

the proposed cooling water pipeline corridor.

16.3.17. There are no records of bats within or immediately adjacent to the Proposed

Development Site or DCO Site, however there are records of bats roosts situated

within 10km of the DCO Site which are utilised by greater horseshoe bats

(Rhinolophus ferrumequinum) and lesser horseshoe bats (Rhinolophus

hipposideros) which are listed on Annex II of the Habitat Directive and for which

the Avon area is considered a national stronghold for this species. Lesser

horseshoe bats are also listed as Priority species on the South Gloucestershire

BAP. The closest greater horseshoe bat roost is approximately 7km south of the

Proposed Development Site. The closest lesser horseshoe roost record

(hibernation roost) is located approximately 4.5km south of the Proposed

Development Site.

16.3.18. The greatest concentration of roosts is situated to the south of the Proposed

Development Site towards the Avon Gorge area. Species which have been

recorded within 10km of the Proposed Development Site include: Noctules

(Nyctalus noctula); Leisler’s (Nyctalus leisleri), Serotine (Eptesicus serotinus),

Common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle (Pipistrellus

pygmaeus) and unidentified pipistrelle species, Brown long-eared (Plecotus

auritus), Daubenton’s (Myotis daubentonii) and Unidentified myotis species


May 2014 Page 16-18

(Myotis spp.). The closest bat activity records to the site are approximately 3km.

Barbastelle bat (Barbastella barbastellus) activity has been recorded in Ashton

Court Estate. This is a rare species listed on Annex II of the Habitats Directive.

Field Surveys

16.3.19. Baseline information arising from the surveys is presented in summary below first

for the Proposed Development Site and then for the proposed cooling water

pipeline corridor. Full descriptions and data from each survey are presented in

Appendices K Part 2 to Part 8, Volume II of this PEI Report.

Extended Phase 1 Habitat Survey

16.3.20. The technical report for the Extended Phase 1 Habitat survey is included within

Appendix K Part 2, Volume II of this PEI Report. Summary descriptions of the

habitats are provided below, with their value/sensitivity based on Table 16-2.

Figure 16-3, Volume III of this PEI Report illustrates the habitat features found

within the Proposed Development Site.

16.3.21. The Proposed Development Site largely consists of grazing land interspersed

with rhines and patches of scrub. The patches of scrub present onsite are a

common habitat in the wider area and support a low species diversity. The scrub

habitat is therefore considered to be of Low (Borough) value.

16.3.22. A small area of immature elm woodland onsite is species poor and does not meet

the criteria for inclusion under the Woodland Priority Habitat within the SGC BAP.

The habitat however increases the structural diversity of the Proposed

Development Site and is therefore considered to be of Low (Borough) value

within the context of the site.

16.3.23. Three individual mature trees on-site increase the structural diversity of the

Proposed Development Site, and the deadwood habitats which they contain are

otherwise absent from the remainder of the Site. This habitat is therefore

considered to be of Low (Borough) value within the context of the Site.

16.3.24. Areas of semi-improved grassland occur towards the northwest of the Proposed

Development Site, and in a strip to the south of the Red Rhine. They are

considered to be of Low (Borough) value within the context of the Proposed

Development Site. The remaining grassland habitat within the Proposed

Development Site boundary is classified as poor semi-improved due to low

species diversity. This habitat is considered to be of Very Low value.

16.3.25. A small area of tall ruderal habitat type is present within the Proposed

Development Site. This is a common habitat in the wider area and supports a low


May 2014 Page 16-19

species diversity. This habitat within the Proposed Development Site is

considered to be of Very Low value.

16.3.26. The water bodies, particularly those which are permanent features, increase the

biodiversity value of the study area. The Red Rhine currently crosses the centre

of the Proposed Development Site in an east to west direction and discharges

into the Severn Estuary at New Pill Gout. A number of other rhines cross the

Proposed Development Site, the largest of which, the Crook’s Marsh Stream,

drains into the Red Rhine from the south. Chapter 14: Flood Risk, Hydrology and

Water Resources provides further details of the drainage of the site and the wider

Red Rhine catchment.

16.3.27. Rhines are a habitat featured within the SGC BAP, although the rhine system

onsite is not considered to be sufficiently large to justify valuation at Medium

(County) level, based on the criteria presented in Table 16-2, and therefore a

Low (Borough) value has been attributed to them. Their value as a habitat for

protected species may be greater and this will be informed by further survey.

16.3.28. Hedgerows are Priority Habitats within the UKBAP and SGC BAP. There is a

single hedgerow onsite, which is considered to have poor diversity. Taking this

into account the hedgerow is therefore considered to be of Low (Borough)

conservation value.

16.3.29. The mosaic of habitats on the Proposed Development Site means that as a

whole the value of them is higher than the individual elements alone. The

interconnected nature of these lead to them being considered as of Medium

(County) conservation value.

Extended Phase 1 Habitat Survey – Other DCO Land

16.3.30. The technical report for the Extended Phase 1 Habitat survey is included within

Appendix K Part 9, Volume II of this PEI Report.

16.3.31. Habitats within the proposed cooling water pipeline corridor consisted of a range

of small parcels of land associated with the linear nature of the site, comprising

hardstanding, dense continuous scrub, scattered scrub, tall ruderal, semi-

improved neutral grassland, improved grassland, amenity grassland, marshy

grassland, standing water, rhines, tree lines, ornamental screening, hedge and

trees, tree-lines, scattered broadleaved trees, broadleaved plantation woodland,

semi-natural broadleaved woodland, industrial units, bridges and culverts.

16.3.32. The value of the habitats is primarily associated with their potential to support

protected or notable species, for which surveys are ongoing. The baseline data

for these, together with potential effects of the DCO Application, and any

mitigation or residual effects will be reported further in the ES.


May 2014 Page 16-20

Protected or Notable Species Potential

16.3.33. Based on the Phase 1 Habitat Survey the Proposed Development Site was

considered to have potential to support a number of protected species including

some, such as badger, otter, water vole, and bats, which receive statutory

protection. Habitats suitable for these species/faunal groups are summarised in

Table 16-6 below.

Table 16-6: Habitat Potential for Protected Species and Other Fauna within the Proposed

Development Site

Species Habitat potential

Badger Spoil heaps in a number of locations, notably the northern boundary of the site. Foraging paths throughout the Site. Species specific surveys have therefore been undertaken.

Otter Rhines may provide foraging habitat and commuting routes to Severn Estuary. Species specific surveys have therefore been undertaken.

Water vole Wet rhines onsite, particularly Red Rhine, provide good quality water vole habitat. Species specific surveys have therefore been undertaken.

Dormice No suitable habitat present, therefore no further surveys have been undertaken.

Bats Waterbodies, scrub and grassland on-site provide suitable foraging and commuting habitat for bats. The 3 mature trees at the western end of the Proposed Development Site provide some suitable roosting habitat. Species specific surveys have therefore been undertaken.

Breeding birds Scrub, grassland and waterbodies provide suitable nesting habitat for breeding birds (including ground nesting birds and water fowl) and wintering birds. Species specific surveys have therefore been undertaken.

Amphibians (including great crested newt)

Standing waterbodies (ponds and ditches) provide suitable habitat for amphibians. The rhines have limited potential for this species. Species specific surveys have therefore been undertaken.

Reptiles All habitats on-site are suitable for use by common species of reptiles, e.g. slow worms, grass snakes, common lizards and adders. Suitable habitat is present to support these species in both summer and winter (during hibernation). Species specific surveys have therefore been undertaken.

Terrestrial and aquatic invertebrates

Mosaic of standing water and scrub offers suitable habitat for both aquatic and terrestrial invertebrates. Species specific surveys have therefore been undertaken.

Flora Habitats on-site are common and widespread. Potential to support protected or notable species of flora is low. No further surveys have therefore been undertaken

Species Specific Surveys

16.3.34. The following section summarises the results of species specific surveys

undertaken of the Proposed Development Site and Other DCO Land during

2013, and indicates where further surveys will be undertaken during 2014. Full


May 2014 Page 16-21

details of the surveys, including methodology, results and raw data are presented

in Appendices K Parts 2 to 8, Volume II of this PEI Report.

Bats – Roost Potential and Activity on Proposed Development Site

16.3.35. A group of three mature ash (Fraxinus excelsior) trees were identified to have the

potential to support roosting bats onsite. No evidence of bats using these trees

was found from either the inspections or the emergence/re-entry surveys.

16.3.36. The activity survey results and analysis of bat recordings suggests that six bat

species - common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle

(Pipistrellus pygmaeus), noctule (Nyctalus noctula), serotine (Eptesicus

serotinus), Brandt’s (Myotis brandti) and Leisler’s (Nyctalus leisleri) were

recorded using the Proposed Development Site across both transects in low

numbers from the activity surveys.

Bats – Activity on the Other DCO Land

16.3.37. On the proposed cooling water pipeline corridor common pipistrelle, soprano

pipistrelle and noctule were recorded foraging above the group of ponds

hydrologically linked to the Salt Rhine, southwest of the Fire and Rescue Training

Centre, commuting and foraging along Moorend Farm Avenue and the lane to

the west of the Bristol WWTW. Common pipistrelle was recorded commuting

above Rhines to the southwest of the Proposed Development Site.

16.3.38. Myotis species (sound analysis indicated Brandt’s) were recorded foraging on the

proposed cooling water pipeline corridor close Moorend Farm Avenue.

Breeding Birds - Proposed Development Site

16.3.39. No species on the EU Wild Birds Directive Annex 1 and Wildlife and Countryside

Act Schedule 1 were recorded on the Proposed Development Site.

16.3.40. Four wild bird species that are red listed as birds of conservation concern within

the UK and were breeding, likely to be breeding, or had potential to be breeding

onsite were skylark (Alauda arvensis), lapwing (Vanellus vanellus), song thrush

(Turdus philomelos) and linnet (Carduelis cannabina). Of these, all except skylark

were confirmed or were considered likely to be breeding on the Red Rhine-

Ableton Lane sector of the Proposed Development Site and surrounding land.

Skylark had potential to be breeding at this location.

16.3.41. A pair of lapwing was exhibiting nesting behaviour just outside of the Proposed

Development Site boundary. Lapwing has declined as a breeding species by

over 50% in the past 25 years.


May 2014 Page 16-22

16.3.42. Singing song thrush was recorded and is listed as a bird of conservation concern

due to a decline in the breeding population of greater than 50% since 1969

(although there are over 1.1 million pairs). Linnet is red-listed for the same

reason and was confirmed as breeding. There are over 500,000 pairs in the UK.

Skylark has declined by greater than 50% as a breeding species since 1969.

16.3.43. Three species confirmed or likely to be breeding on the Proposed Development

Site that have ‘amber’ Bird of Conservation Concern (BOCC) status were

dunnock (Prunella modularis), common whitethroat (Sylvia communis) and reed

bunting (Emberiza schoeniclus).

16.3.44. Local BAP species recorded during surveys on or adjacent to the Proposed

Development Site were skylark, linnet, reed bunting, dunnock, song thrush and

lapwing.

Breeding Birds - Other DCO Land

16.3.45. Cetti’s warbler (Cettia cetti), a species listed on the EU Wild Birds Directive

Annex 1 and Wildlife and Countryside Act Schedule 1, was heard singing from

marginal vegetation at lagoons on the Bristol WWTW site.

16.3.46. Three species that have ‘red’ Bird of Conservation Concern (BOCC) status were

recorded; skylark, song thrush and linnet were also confirmed as breeding along

the proposed cooling water pipeline corridor. Fourteen species confirmed or likely

to be breeding along the proposed cooling water pipeline corridor that have

‘amber’ BOCC status were mallard (Anas platyrhynchos), shelduck (Tadorna

tadorna), gadwall (Anas strepera), little grebe (Tachybaptus ruficollis), kestrel

(Falco tinnunculus), lesser black-backed gull (Larus fuscus), stock dove

(Columba oenas), green woodpecker (Picris viridis), mistle thrush (Turdus

viscivorus), dunnock (Prunella modularis), common whitethroat (Sylvia

communis), willow warbler (Phylloscopus trochilus), bullfinch (Pyrrhula pyrrhula),

and reed bunting (Emberiza schoeniclus).

16.3.47. Local BAP species recorded during surveys of the proposed cooling water

pipeline corridor were skylark, tree pipit (Anthus trivialis), linnet, cuckoo (Cuculus

canorus), reed bunting, spotted flycatcher (Muscicarpa striata), dunnock, bullfinch

(Pyrrhula pyrrhula), starling (Sturnus vulgaris), and song thrush.

Non-Breeding Birds - Proposed Development Site

16.3.48. The following species relevant to the SPA and Ramsar designation were noted

on the Proposed Development Site:

• Lapwing – small numbers (less than 20) were heard on inland area at

night. In inclement weather (snow cover), 67 individuals were recorded


May 2014 Page 16-23

during the day onsite. Lapwing are listed as a BOCC species since at

least 20% of the European population winters in the UK.

• Dunlin – occasional very low counts on inland area (maximum 14

individuals). The UK population has declined by over 50% in the longer

term (since 1969) and the majority of the wintering population is confined

to only a few UK sites.

• Teal - mostly on the estuary, with single figure numbers on the inland

section of the Proposed Development Site. Listed as at least 20% of the

European population winters in the UK.

• Ringed plover – individuals or pairs of birds recorded on estuary and

inland section of the Proposed Development Site. Listed as at least 20%

of the European population winters in the UK.

• Snipe – up to 35 individuals recorded at night on inland section of the

Proposed Development Site. Snipe is a species of conservation concern

at European population level.

16.3.49. A pair of peregrine falcons was regularly observed resting on pylons within the

Proposed Development Site.

16.3.50. Other species of conservation concern recorded during the surveys on the

Proposed Development Site footprint were:

• Herring gull – on hard standing areas and associated seasonal water

bodies immediately adjacent to the Proposed Development Site, and

also on field along eastern and northern site boundary foraging. Flocks of

up to 111 were recorded. The UK non-breeding population has declined

by over 50% over a period of 25 years.

• Kestrel – a pair was present on inland area of the Proposed

Development Site. This is a species of conservation concern at

European population level.

• Barn owl – two individuals observed, hunting within the Proposed

Development Site. This is a species of conservation concern at

European population level.

• Kingfisher – one individual recorded on the Proposed Development Site

on one occasion. This is a species of conservation concern at European

population level.

Amphibians

16.3.51. Desk study data has indicated records of smooth newt (Lissotriton vulgaris) and

great crested newt (Triturus cristatus) within 1.5km of the centre of the Proposed


May 2014 Page 16-24

Development Site. Previous surveys undertaken in 2007 and 2010 to inform

proposals for cumulative schemes in the area identified the presence of great

crested newts in three ponds over 500m north of the Proposed Development

Site.

16.3.52. The surveys confirmed presence of a low population of smooth newts and no

evidence of palmate newts or great crested newts on the Proposed Development

Site. Therefore no further action with regards to these species needs to be taken.

16.3.53. GCN surveys of ponds in proximity to the proposed cooling water pipeline

corridor will be undertaken in 2014 and reported in the ES.

Reptiles

16.3.54. A maximum of eight adult grass snakes and two juvenile grass snakes were

recorded on the Proposed Development Site during one survey visit. Reptiles

were found to be using the scrub and grassland habitat to the north of the Site,

and the south facing bank adjacent to the Red Rhine at the southern end of the

Site. Due to the presence of juveniles it was deemed that grass snakes are

breeding in the scrub and grassland mosaic at the northern end of the Site.

Based on survey results, there is considered to be a high (>4 individuals / ha

(HGBI, 1998)) population of grass snake. The Proposed Development Site is

thus considered to be of Medium (County) value for reptiles.

16.3.55. Surveys of suitable reptile habitat in the proposed cooling water pipeline corridor

will be undertaken during 2014 and reported in the final ES.

Badgers

16.3.56. Based on preliminary findings it is likely that badgers exit within the scrub onsite

or in the vicinity of the Site, however further surveys will be undertaken in

2013/14 for badger presence on the Proposed Development Site and the

proposed cooling water pipeline corridor. The results will be presented in the final

ES.

Water Vole

16.3.57. Based on preliminary findings it is likely that water voles occur within the Red

Rhine. Further surveys will be undertaken in 2013/14 for water vole presence on

the Proposed Development Site and proposed cooling water pipeline corridor.

The results will be presented in the final ES.


May 2014 Page 16-25

Otter

16.3.58. Further surveys will be undertaken in 2013/14 for otter presence on the Proposed

Development Site and the proposed cooling water pipeline corridor, and the

results will be presented in the final ES.

Invertebrates – Terrestrial on the Proposed Development Site

16.3.59. In samples from the Proposed Development Site analysed to date, six species of

conservation interest have been identified, including one Nationally Scarce A and

NERC S41 species Necklace Ground Beetle (Carabus monilis) and four

Nationally Scarce B species: Red-shouldered Longhorn Beetle (Anaglyptus

mysticus), Coal Blackclock beetle (Pterostichus anthracinus), Clay Blackclock

(Pterostichus longicollis), and a wolf spider (Pardosa agrestris). Nationally Scarce

A species are currently known to exist in 30 or fewer ten-kilometre squares.

Nationally Scarce B species are currently known to exist in 31 - 100 ten-kilometre

squares.

16.3.60. Further surveys, including suitable habitat on the proposed cooling water pipeline

corridor will be undertaken in 2014 for terrestrial invertebrate presence onsite,

and the results will be presented in the ES.

Invertebrates – Aquatic

16.3.61. Analysis of aquatic invertebrates sampled in 2013 is ongoing and the data will be

reported in the ES. Further surveys will be undertaken in 2013/14 for aquatic

invertebrate presence onsite, and the results will be presented in the final ES.

Fish

16.3.62. Analysis of the importance of the rhines and ditches to support fish will be

reported in the final ES. Records of eel (Anguilla anguilla) exist for the Red

Rhine.

Resource Evaluation

16.3.63. Table 16-7 summarises the resource evaluation for the habitats and species

discussed above.

Table 16-7: Resource Evaluation

Species Habitat potential Explanation

Designated sites

Very High (International) The Severn Estuary SAC, SPA and Ramsar sites lie, at the closest point, approximately 400m from the nearest point of the Proposed Development Site and 140m from the nearest point of the proposed cooling water pipeline corridor.


May 2014 Page 16-26


High (National) The Severn Estuary SSSI is contiguous with the international designations and is designated for supporting nationally important examples of the same habitats and species, along with additional features of national importance.

High (National) Several other SSSIs and one NNR occur within 10km. These are all designated for nationally important features.

Medium (County) There are several LNRs within 10km and SNCIs within 1.5km of the centre of the Proposed Development Site and 1km of the proposed cooling water pipeline corridor.

Habitats Medium (County) value for the Red Rhine and for the habitat mosaic.

Low (Borough) value or Very Low value for the other habitats

There is evidence that the Red Rhine supports water vole, and habitat for eels.

Individually, the remaining habitats on the Proposed Development Site are considered to be of Low (Borough) value or Very Low value

Bats – roosting potential

Very Low Three mature ash trees on the Proposed Development Site have high/moderate potential to support roosting, but activity surveys did not find evidence of presence of roosting bats

Bats – foraging potential

Low (Borough) The linear features and hedgerow on the Proposed Development Site provide foraging and commuting habitat for bats. Six species were recorded foraging within the Proposed Development Site, albeit in low numbers.

Within the proposed cooling water pipeline corridor the rhines and ponds, notably the Salt Rhine ponds along the water pipeline route, attract foraging bat species.

Breeding birds Low (local) – Proposed Development Site

Medium (County) – Proposed Cooling Water Pipeline Corridor

The Proposed Development Site provides limited habitat of value for breeding birds with the exception of a few trees, a few areas of scrub and small lengths of hedgerow. No WCA Schedule 1 species were recorded during surveys and the site supports only low numbers of common species.

Cetti’s warbler, a Schedule 1 species, was recorded on the proposed water pipeline corridor, increasing its perceived value.

Non-breeding birds

Medium (County) – Proposed Development Site

Value to be determined in the ES for the Proposed Cooling Water Pipeline Corridor

The Proposed Development Site was found to support negligible counts of species for which the Severn Estuary SPA and Ramsar sites were designated, either as cited individual species or as part of species listed as part of overall waterbird assemblages. However, the grassland habitats onsite did support populations of wading birds such as snipe and lapwing during the winter period.

The proposed cooling water pipeline corridor runs close to lagoon habitats, and further analysis of desk study data will be undertaken for the ES in order to determine whether the cooling water pipeline route is considered to


May 2014 Page 16-27


be of value to non-breeding birds

Amphibians N/A Survey data and receptor assessment will be reported in the final ES.

Reptiles Medium (County) – Proposed Development Site

Negligible – Proposed Cooling Water Pipeline Corridor

Presence of a high population of grass snakes on the Proposed Development Site.

Habitats along the proposed cooling water pipeline corridor were not considered likely to contain significant populations of reptiles, or were considered to be edges of larger habitat parcels

Badger N/A Survey data and receptor assessment will be reported in the final ES.

Water vole N/A Survey data and receptor assessment will be reported in the final ES.

Otter N/A Survey data and receptor assessment will be reported in the final ES.


N/A Survey data and receptor assessment will be reported in the final ES.

Fish Low (local) The Red Rhine has records of eel

Flora Negligible Specific botanical surveys were not undertaken, but the Phase 1 habitats survey did not identify and notable species, or non-native or injurious plants.

Future Baseline Conditions

16.3.64. It is anticipated that prior to construction, the ecological baseline of the Proposed

Development Site will change as a result of other developments that do not form

part of the DCO Application.

16.3.65. These other developments, as detailed in Chapter 7: Assessment Methodology

of this PEI Report, include;

• Construction of a new Spine Access Road along the northern perimeter

of the Proposed Development Site, which would connect the roundabout

immediately east of the Proposed Development Site to the A403 to the

west. This will also require a construction right of way within the northern

part of the Site in order to allow access for construction plant to the

southern side of this road for heavy construction plant.

• Construction of a new dry channel for the Red Rhine along the northern

boundary of the Proposed Development Site. No flow diversion will take

place – this will form part of this DCO Application. Again, a construction

right of way will be required within the Proposed Development Site that

will be cleared and levelled.


May 2014 Page 16-28

• Construction of the SITA Severnside Energy Recovery Centre,

immediately west of the Proposed Development Site. SITA has recently

constructed a haul road through the centre of the Proposed Development

Site to provide access from the roundabout immediately to the east and

its site to the west.

16.3.66. These schemes will have been implemented prior to the start of construction of

the Proposed Development and have the potential to change the baseline

conditions within the Proposed Development Site from those that were assessed

and reported above.

16.3.67. There would be no direct change to any statutory or non-statutory designated

sites as a result of the developments described above. Given statutory and policy

protection of these sites, no measurable changes are anticipated as a result of

other consented developments. The value of these sites is thus assumed to be

the same as the current baseline.

16.3.68. There will be loss or change to some of the existing habitats within the Proposed

Development Site. Grassland and scrub habitat are likely to be cleared from the

northern part of the Proposed Development Site for the spine access road and

diverted Red Rhine corridor. A short stretch of ditch, scrub and grassland habitat

is likely to be cleared from the existing Red Rhine corridor to allow for the haul

road through the centre of the Proposed Development site to the Severnside

Energy Recovery Centre.

16.3.69. The proposed Red Rhine corridor will be isolated from the drainage network,

although it is likely to hold some water from ground and surface water sources.

Based on a review of preliminary engineering drawings by Severnside

Distribution Land Ltd, the diverted rhine appears to have been designed

specifically for the conveyance of surface water rather than ecological mitigation,

with steep bank profiles. Depending on local conditions, reed vegetation may be

expected to develop within the channel, with grassland re-establishing on areas

adjoining the channel.

16.3.70. The network of rhines are expected to reduce in value from Medium (County) to

Low (Borough) as a result of these developments, although this is an estimate

based on relatively little publically available data and the proposed gradients of

the new channel. The remaining areas may remain as Low (Borough) value, or

reduce to Very Low value.

16.3.71. Changes to the extent of habitats on the Proposed Development Site may be

expected to result in some reduction and fragmentation of foraging habitat for

each of the species groups recorded on the Proposed Development Site. The

grassland habitat in the eastern part of the Proposed Development Site will


May 2014 Page 16-29

remain largely intact, although there will be temporary disturbance due to

construction traffic through the Site. The value for non-breeding birds is therefore

expected to remain as Medium (County). Loss of scrub and semi-improved

habitat in the northern part of the Proposed Development Site may also reduce

the value of the Proposed Development Site for reptiles from Medium (County) to

Low (Borough).

16.3.72. The value of the Proposed Development Site for remaining species receptors is

considered to remain as per the current baseline.

16.3.73. The value of habitats on the proposed cooling water pipeline corridor is unlikely

to change as a result of these other developments described above.

16.3.74. Table 16-8 summarises the value of the ecological receptors on the Proposed

Development Site once the future baseline conditions are taken into account.

Table 16-8: Value of Ecological Receptors under Future Baseline Conditions

Receptor Value within the Proposed Development Site

Value within the Water Pipeline Corridor

Designated sites in the vicinity of the DCO Site

Severn Estuary SAC/SPA/Ramsar

Very High Very High

Severn Estuary and all other SSSIs and Leigh Woods NNR

High High

LNRs and SNCIs/AWTSs

Medium Medium

Habitats Woodland Negligible Negligible

Scrub Low To be reported in ES

Mature trees Low To be reported in ES

Semi-improved grassland

Low To be reported in ES

Tall ruderal Low To be reported in ES

Rhine, ditches and waterbodies

Low To be reported in ES

Hedgerows Low To be reported in ES

Species Bats Low Low

Breeding birds Low Medium

Non-breeding birds Medium Low-Medium

GCN Low To be reported in ES

Reptiles Low Negligible

Badger To be reported in ES To be reported in ES

Water vole To be reported in ES To be reported in ES

Otter To be reported in ES To be reported in ES


May 2014 Page 16-30

Receptor Value within the Proposed Development Site

Value within the Water Pipeline Corridor

Terrestrial invertebrates

To be reported in ES To be reported in ES

Aquatic invertebrates To be reported in ES To be reported in ES

Fish Low To be reported in ES

Flora Negligible To be reported in ES


16.4.1. A number of impact avoidance measures have been incorporated into the design.

These measures have therefore been taken into account during the assessment

presented in this chapter.

16.4.2. The draft landscaping masterplan is illustrated in Figure 17-15, Volume III of this

PEI Report and has been designed to mitigate a number of environmental effects

or enhance the Site for ecology. In summary it comprises:

• An 8m easement along the southern side of the repositioned Red Rhine

to allow access for maintenance. This easement will be planted with

grassland, ruderal and occasional scrub plants.

• In areas of habitat suitable for reptiles (mosaic of scrub, grassland, tall

ruderals and bare ground), hibernacula will be created. The southern

boundary of the Proposed Development Site will include a mosaic of

habitats planted with tall ruderals, and hedgerow and scrub habitats

interspersed with open grassland and bare ground. There is no limit on

the number or density that could be created, but one approximately every

50-100m would be appropriate.

• Strips of rough, tussocky grassland will be maintained alongside the

hedgerow and rhines in order to provide suitable habitat for hunting barn

owls. The 8m easement along the Red Rhine will have value for foraging

barn owl, and for reptiles and water vole if it is allowed to develop into a

tussocky and long grass strip, rather than being closely mown. The strips

will comprise a grass mix suitable for unimproved grassland habitat,

incorporating species such as false oat grass (Arrhenatherum elatius), red

fescue (Festuca rubra), meadow-grasses (Poa sp.), Yorkshire fog (Holcus

lanatus) and cocksfoot (Dactylis glomerata).

• Up to 0.38ha of surface water features will be incorporated in to the

Proposed Development Site as landscaped attenuation ponds/ditches.

Where practical, these will have shallow sloping margins, allowing access


May 2014 Page 16-31

and egress for amphibians, reptiles and small mammals. They will be

planted with marginal vegetation focusing on aquatic grasses, such as

creeping bent (Agrostis stolonifera) and the sweetgrasses (Glyceria

species) which provide good invertebrate habitats and provide cover for

breeding water birds, and for grass snake. Submerged and floating

vegetation should be allowed to colonise naturally. Although not required

for water attenuation, the indicative layouts shown in Figure 4-2 and 4-3

in Volume III of this PEI Report include an additional long, thin surface

water feature along the southern boundary of the CCR Site, which can

therefore be designed specifically for ecological benefits rather than flood

attenuation.

• Incorporation of green roofs and brown roofs onto some of the lower

structures will provide suitable habitat for terrestrial invertebrates. The

roofs will, where possible, incorporate logs to provide a habitat for

invertebrates, wetland areas for the establishment of mosses and lichens,

and boulders and stones.

• Any woodland, scrub, mature trees and hedgerow onsite that are lost to

construction or the operational site will be replaced with alternative

provision onsite with planting of native species. Areas of tree and shrub

planting include along the northern boundary of the Proposed

Development, immediately south of the 8m easement along the

repositioned Red Rhine, the area of landscaping between the Generating

Station Site and CCR Site, and additional areas in the west and south of

the Proposed Development Site.

16.4.3. A landscape and biodiversity masterplan will present details of the design,

planting and long term management of the areas described above, and will be

agreed in liaison with the local authorities and Natural England following receipt

of the DCO. A preliminary landscape and biodiversity masterplan is presented in

Figure 17-15, Volume III – Figures of this PEI Report, which will be updated as

part of the final Environmental Statement.

16.4.4. As a precautionary measure, following good practice guidance, any lighting

scheme associated with the Proposed Development will consider bats within the

detailed design. Landscaping associated with the Proposed Development has

the potential to be used by foraging and commuting bats in future and in order to

maximise the potential of the landscaping to enhance the value of the site for

bats, the risk of lighting disturbance to bats should be minimised. Lighting should,

where possible, be directional (i.e. illuminating as little of the surrounding

environment as possible), and low intensity.


May 2014 Page 16-32


16.5.1. This section describes the potential changes associated with the construction,

operation and decommissioning of the Proposed Development, prior to any

mitigation, and identifies any resulting ecological effects.

Construction Phase

16.5.2. The following changes during enabling works and construction of the Proposed

Development Site and proposed cooling water pipeline corridor are considered to

have the potential to affect ecological receptors:

• Loss and fragmentation of habitats through temporary landtake, and

effects on species that utilise these habitats;

• Disturbance to sensitive species through noise, lighting and human

activity from construction activities;

• Pollution of water courses through run-off. Topsoil and excavated/fill

material will be stored in designated areas away from watercourses, as

explained in Chapter 14: Flood Risk, Hydrology and Water Resources.

In order to avoid pollution risks or risk of physical damage to the Red

Rhine and other ditches prior to their diversion, the CEMP will include

measures to avoid pollution events from works carrying risk within 10m of

the rhines. Reptile and water vole proof fencing will be erected along the

rhine system to exclude these species from the Proposed Development

Site during the clearance phase, if later surveys find these species to be

present onsite;

• Changes to the hydrology of the Proposed Development Site and

proposed cooling water pipeline corridor due to diversion of

watercourses, land raising and other construction activities. This could

directly affect any water bodies hydrologically linked to the Proposed

Development Site, or it could create indirect effects by alteration of

habitat quality where such habitat are dependent on water tables;

• Effects on ecological receptors through dust creation and deposition, and

through atmospheric emissions through movement of construction

vehicles to, from, and within the Site. Such effects can be direct in terms

of physical changes to habitats, with direct and also indirect effects on

species that rely on such habitats. Mitigation for dust deposition is dealt

with in Chapter 11: Air Quality; and

• Displacement of protected species through diversion of the existing Red

Rhine watercourse into the new channel, and through works close to

watercourses along the proposed cooling water pipeline corridor. The


May 2014 Page 16-33

need for this work to be undertaken during a particular time of year will

be identified following further survey work on water vole presence.

16.5.3. The construction of the proposed cooling water pipeline and electrical connection

is not expected to have any significant ecological implications, however in this

PEI report this is only discussed in terms of its potential to affect birds and bats

based on the survey works undertaken to date. Survey data for other protected

species and habitats along the proposed cooling water pipeline corridor will be

collected in spring/summer 2014, to enable a discussion on the potential effects

and their mitigation for the associated development to be presented in the final

ES.

Designated Sites - Temporary Land Take

16.5.4. There will be no landtake from sites designated for wildlife interest, either

statutory or non-statutory, associated with the Proposed Development or

proposed cooling water pipeline.

16.5.5. There is the potential for nearby designated sites such as the Severn Estuary

SPA/SAC/Ramsar/SSSI, and wetland sites such as Hallen’s Marsh SNCI to be

indirectly affected due to the displacement of birds from the Proposed

Development Site due to habitat loss. Although the CCR Site will be reinstated

following the construction phase, it is not expected to be returned to its current

ecological value or support marshy grassland habitat. Its value is therefore

considered likely to decline to Low (local) value.

16.5.6. The magnitude of change, or impact, on displaced birds on the Severn Estuary

SPA/SAC/Ramsar/SSSI is considered to be Low to Medium, and therefore,

based on Table 16-4, the predicted effects are consider to be minor adverse.

Effects on non-statutory sites which are of Medium value are considered to be

negligible.

16.5.7. The diversion of the Red Rhine will not have any effects on designated sites, as

there will be no significant changes in water flows to the estuary and the rhine is

not linked to other designated sites. Therefore there will be a negligible effect on

designated sites through diversion of the Red Rhine.

Designated Sites - Disturbance

16.5.8. Disturbance of species which form a component of the Severn Estuary SPA,

Ramsar, SSSI or other non-statutory SNCIs could potentially occur through

increased lighting, human presence or noise during construction within the


16.5.9. The nearest designated site, the Severn Estuary lies over 400m to the west of

the Proposed Development Site and there is already construction activity, notably


May 2014 Page 16-34

from the SITA Severnside Energy Recovery Centre site, between the Proposed

Development Site and the designation. Noise disturbance has been assessed in

Chapter 12: Noise and Vibration. It is considered that the predicted noise levels

from enabling works and construction activities fall below the measured LAeq

levels at the nearest habitat receptor, which is Chittening Warth within the Severn

Estuary SAC, SSSI and Ramsar sites. The significance of this predicted effect is

therefore assessed as negligible.

16.5.10. Higher noise levels are predicted during site clearance with road construction

noise levels predicted to be 60dB prior to mitigation. However, there is no

demolition work and only limited trees within the site which will be cleared and

this work is expected to take place over a very short space of time.

16.5.11. The northern end of the proposed cooling water pipeline corridor will pass within

approximately 140m of the SPA, Ramsar and SSSI. Noise levels during the

construction of the pipeline are predicted to be 56dB, which is slightly higher than

ambient levels, and was considered in the noise assessment to be minor

adverse. Depending on timing and methodology of works there could be potential

for disturbance of bird species. Disturbance is considered to be a Low magnitude

of change, and therefore the effect on the Severn Estuary is expected to be

minor adverse, and temporary in nature.

Designated Sites - Reduced Water Quality – Run-off

16.5.12. Without mitigation, it is possible that construction activities, particularly removal of

topsoil and excavation, could lead to silt and pollutants entering the Red Rhine

on site, which is hydrologically connected to the Severn Estuary. A CEMP will be

implemented for the Proposed Development and associated infrastructure, which

will include procedures for the storage of chemicals, non-road mobile vehicle

movements, and protection of water courses. Even with these measures in place,

there is likely to be some re-suspension of silt when the new Red Rhine diversion

is connected to the existing watercourse, although this should be temporary.

16.5.13. Given the silty environment of the estuary, the small volumes of silt which may be

re-suspended are considered to be imperceptible when compared with the

sediment loads carried by the tides. The magnitude of change resulting from run-

off on designated sites is considered to be negligible and the significance of the

predicted effect minor adverse.

Designated Sites - Groundwater Contamination

16.5.14. The potential for the Proposed Development to affect ecological receptors, in

particular SNCIs designated for rhines and ditches or dependent species,

through alteration of groundwater levels, or through contamination of

groundwater has been considered. Based on Chapter 13: Ground Conditions the


May 2014 Page 16-35

effect of the development on ground conditions is considered to be negligible. If

contamination is encountered during construction appropriate remediation

measures will be implemented.

16.5.15. The magnitude of change resulting from ground water contamination on

designated sites is therefore considered to be negligible.

Designated Sites - Air Quality

16.5.16. There are no statutory or non-statutory designated sites within 200m of the main

works site (the distance over which Department for Transport guidance

recommends assessment on ecological receptors should apply for road traffic

emissions) and therefore no likely effects of gaseous emissions from construction

plant and equipment onsite are expected.

16.5.17. Elevated levels of construction traffic accessing the Site could theoretically

contribute to reduced air quality on sites within 200m of main access routes

(primarily the A403). Habitats such as saltmarsh are potentially vulnerable to

reduced air pollution and the construction traffic emissions associated with the

enabling works will lead to an increase in annual mean NOX concentrations at

locations within 100m of the Severn Estuary designated sites. The increase will

be greatest at locations immediately adjacent to the A403, where annual mean

concentrations are already in excess of the national air quality objective for that

pollutant, and also the critical load for coastal saltmarsh. The Severn estuary

designated sites are located 25m from the A403 at their closest point. At

distances of 30-35m from the A403, NOX levels drop below the critical load for

coastal saltmarsh. The main reason for the exceedance is the high background

concentrations. It is considered that construction vehicles would only contribute

a negligible air quality effect on this receptor, as discussed in Chapter 11: Air

Quality.

16.5.18. Dust effects would be theoretically possible on the Severn Estuary designated

sites, but these are situated in the opposite direction to the prevailing wind and

400m from the Proposed Development Site. Given the mitigation measures

proposed in Chapter 11: Air Quality for controlling dust emissions, the prevailing

wind direction and the level of dispersion that occurs over a distance of 400m,

the effect of dust is expected to be negligible.

Habitats - Temporary Land Take

16.5.19. Temporary land take will lead to the loss of habitat onsite. These habitats

comprise primarily poor semi-improved grassland and tall ruderal habitat with

small amounts of scrub, and ditch habitat. Following the construction stage, the

habitats within the CCR Site would be restored to semi-improved grassland,

which would re-establish in the short term (less than 5 years).


May 2014 Page 16-36

16.5.20. The existing Red Rhine corridor would be infilled, or used as a shallow swale

water feature along the south of the CCR Site (see indicative layouts in Figures

4-2 and 4-3, Volume III of this PEI Report.

16.5.21. The impact of temporary land take is considered to be Medium, since although it

will affect ‘greater than 20%’ of the Proposed Development Site, it will be partially

reversible in the CCR Site and the areas reserved for below ground utilities,

services and landscaping. Effects on habitats are therefore considered to be

minor adverse, given their Low (Borough) value under the future baseline.

Habitats - Reduced Water Quality due to Run-off and Silt Re-suspension

16.5.22. The diversion of the water flow from the existing Red Rhine into the new channel

is likely to result in some re-suspension of silt as the new channel is flooded, with

the potential for smothering effects on downstream habitats. However, the

volumes of re-suspended silt are likely to be small, and will only occur temporarily

and downstream habitats are likely to comprise a significant silt component. The

magnitude of the change is considered to be Low and given the Low (Borough)

value of the habitats effects are considered to be negligible.

Species

Bats (Roosting and foraging) – Temporary Landtake

16.5.23. The temporary loss of scrub and semi-improved grassland onsite will reduce the

value of the Proposed Development Site for foraging bats. New habitats such as

tree screens and the newly created Red Rhine corridor will provide replacement

linear habitat, and the water attenuation areas will provide some replacement

foraging habitat, although the overall reduction in the area of grassland habitat

will reduce the bat foraging opportunities. Nevertheless, the impact is considered

to be Low and, therefore the overall effect is considered to be negligible.

Bats (Roosting and foraging) - Disturbance

16.5.24. Lighting and night time construction activities have the potential to disrupt flight

lines and foraging routes through the Site. With the loss of the existing Red

Rhine corridor foraging routes within the Proposed Development Site are likely to

be restricted primarily to the boundaries of the Site. Temporary lighting will be

focused on the main works areas at the western end of the Proposed

Development Site, although there is likely to be some spillage into the adjacent

habitat which may be used by foraging bats. Although lighting is known in certain

circumstances to delay bats emerging from a roost, there are no known roost

sites, or habitats suitable to support roosting bats close to the Proposed

Development Site. Of the six species recorded foraging within the Proposed

Development Site, five (common and soprano pipistrelle, nocule, Leislier’s and

serotine) are fast flying species which may be favoured by lighting due to


May 2014 Page 16-37

populations of night flying insects that it supports. One species, Brandt’s may be

disrupted from foraging close to lighting. The impact of lighting is considered to

be Low.

16.5.25. The impact of noise and lighting is considered to be Low, and the overall effect

on bats to be negligible.

Bats (Roosting and foraging) – Reduced Water Quality due to Run-off

16.5.26. Reduced water quality within the newly created Red Rhine corridor has the

potential for impacts on invertebrate populations which bats depend on as a

foraging resource. However, any impacts on water quality are considered to be

temporary following the diversion of the watercourse from the existing channel.

The successful establishment of marginal and aquatic vegetation within the

channel is considered to be most important factor in determining invertebrate

populations. Effects of reduced water quality on bats are thus considered to be

negligible.

Breeding Birds – Temporary Landtake

16.5.27. Temporary landtake will result in the loss of scrub and grassland habitats of value

for breeding birds in the eastern part of the Proposed Development Site. Four

red list species of conservation concern were recorded on the Site, including two,

skylark and lapwing, which are ground nesting and require extensive areas of

grassland habitat. The remaining two red list species, song thrush and linnet

require dense scrub. This portion of the Site will be reinstated to grassland.

Under the future baseline, the Site is considered to be of Low (Borough) value for

breeding birds. Given the Medium impact of temporary landtake, effects on

breeding birds are considered to be minor adverse.

Breeding Birds - Disturbance

16.5.28. Light, noise and human activity during construction could lead to disturbance to

nesting and avoidance of habitats surrounding the Site by breeding bird species.

The highest noise levels are predicted to occur during the site clearance stage,

although with mitigation, noise levels associated with site activities 400m from the

boundary of the Site at Chittening Warth on the Severn Estuary are predicted to

be no more than 10dB.

16.5.29. No noise data is available for habitats adjacent to the Site, but levels are very

likely to be higher than this, and may cause some displacement of birds and

discouragement of nesting activity in habitats immediately adjacent to the Site.

Given the already high levels of industrial activity in the area, and the temporary

nature of operations such as piling, the magnitude of change is considered likely


May 2014 Page 16-38

to be ‘Low’, though this may require re-evaluation as construction plans are

developed.

Non-Breeding birds – Temporary Landtake

16.5.30. The Proposed Development Site was found to be of value to wading birds, in

particular snipe, which is a species specifically listed in the SSSI citation for the

Severn Estuary. Under future baseline conditions the value is likely to be Medium

(County), as noted above. The temporary loss of extensive areas of grassland

habitat is considered to be a ‘Low’ magnitude of change. Whilst there is some

equivalent habitat available to the south of the Proposed Development Site, as

well as marshland that forms part of the SSSI itself, the temporary loss of this

habitat from the Proposed Development Site is considered to be a minor

adverse effect.

16.5.31. When taking this into account with the effects of permanent landtake in the

western part of the Proposed Development Site for the Proposed Development,

and considering that the CCR Site is not expected to be returned to its current

value for marshland habitat, the effects of temporary landtake on non-breeding

birds, specifically snipe, is considered to be moderate adverse, and therefore

significant without mitigation.

16.5.32. It is worth noting that this is based on the value of the CCR Site being ‘Medium’.

However, given the extent of the work onsite currently by third parties associated

with the installation of the new Spine Access Road, Red Rhine diversion, and

creation of a haul road through the Proposed Development Site, it is considered

unlikely that the CCR Site is currently used by snipe or any other birds. It is not

known whether these developers will reinstate the Proposed Development Site to

its pre-disturbed environment and whether the potential effect on non-breeding

can therefore be classified as minor adverse, or if the current site conditions will

be reinstated prior to enabling works for the Proposed Development.

16.5.33. Overarching NPS for Energy (EN-1) advises that DCO requirements and/or

planning obligations should be used not only to mitigate any significant harm

arising from a proposed development on a SSSI but also where possible, to

conserve and enhance the SSSI’s biodiversity interest. The Applicant will

therefore explore opportunities with SGC, BCC and NE to contribute to the

management of land off-site for the benefit of bird interests in the Severnside

area to provide long-term habitat creation and management for species such as

snipe. Further details will be reported in the DCO Application.

Non-breeding Birds - Disturbance

16.5.34. Construction activities have the potential to displace non breeding species such

as snipe and lapwing from the Proposed Development Site. Although some work


May 2014 Page 16-39

areas will be surrounded by noise barriers which will reduce levels of

disturbance, activity on haulage routes and laydown areas in the eastern part of

the site will be unscreened. When considered in combination with the loss of

habitat due to temporary landtake the Proposed Development Site, the suitability

of the site to support non-breeding birds will be considerably reduced during

construction. The impact of disturbance combined with landtake is considered to

be High and the overall effect moderate adverse, and therefore significant

without mitigation. This is based on the site conditions pre-December 2013

however, which no longer exists onsite. The Applicant is willing however to

explore opportunities to contribute to the management of land off-site for the

benefit of bird interests in the Severnside area to reduce this effect to minor

adverse significance.

Reptiles – Temporary Landtake

16.5.35. The site currently supports a medium population of reptiles, which appears to be

focused primarily around the scrub and grassland habitats associated with the

Red Rhine corridor and towards the northern edge of the Site. All of this habitat

will be lost to temporary landtake, although grassland habitat will be established

in the landscaped areas of the scheme, and there will be scrub within the

proposed swale corridor to the south of the CCR Site. However, these habitats

are much smaller in scale than under the current baseline, and will take time to

establish sufficiently to support a viable reptile population. Impacts of landtake

are considered to be Medium, and the effects are considered to be minor

adverse.

Prior to commencement of construction, reptile proof fencing will be erected

along the rhine system to exclude reptiles (and water voles) from the Site during

the clearance phase. A high density of traps will be placed within the Site where

suitable for reptiles, and they will be checked daily for a total of 60 suitable days

prior to the Site being cleared. This will be undertaken during May and June

(when grass snake numbers were highest) and where possible only on fair

weather days where the temperature is between 10 - 20 degrees Celsius.

16.5.36. A precautionary approach to reptile vegetation clearance will be adopted once

the trapping stage has been completed. This will involve clearance in a phased

and controlled manner using hand-held machinery and under ecological

supervision. Ecologists will undertake a ‘finger-tip’ search for reptiles within the

area to be cleared. This will encourage reptiles to vacate these areas of their own

volition. Soil, stones, roots, mammal holes etc. will be checked for reptiles by

hand investigation. If any reptiles are encountered they will be moved to the

translocation area of the retained habitat the other side of the reptile fencing.

Hand strimmers or brush cutters will follow the ecologist’s lead and cut vegetation

to a height of 100mm; the cut material will be hand raked to the sides of the area.


May 2014 Page 16-40

All strimming will be phased, working outwards towards the periphery of the

development footprint to areas which are to be retained. If any reptiles are

encountered, works will need to cease and an ecologist will move the reptiles to a

safe area before recommencing works. All clearance work will be undertaken

during April to September in order to coincide with reptiles' active seasonal period

and where possible will be undertaken within a temperature range of 16 – 24

degrees Celsius in suitable weather conditions.

Reptiles - Disturbance

16.5.37. Construction activity, particularly during the site clearance stage, has the

potential to disturb reptiles within remaining areas of grassland and scrub.

However, given that the receptors are relatively insensitive to noise and light

impacts, the major consideration would be vibration through processes such as

piling, and heavy vehicle movements. The impact is considered to be Low, since

measures to avoid killing and injuring of reptiles through temporary landtake

discussed above would ensure that reptiles were not present within the areas

likely to be affected by vibration effects on Site, though areas of immediately

surrounding habitat could also be subject to disturbance. The effect is therefore


Flora – Temporary Landtake

16.5.38. The Proposed Development Site currently supports a range of common plant

species, with no notable species of flora. Temporary landtake will result in a loss

of plant species, however grassland habitat will be established in the landscaped

areas of the scheme, and there will be scrub within the proposed swale corridor

to the south of the CCR Site. A number of enhancement measures have been

outlined above that are expected to ensure an equivalent range of species is re-

established on the Proposed Development site. The magnitude of change is

therefore considered to be Very Low/Negligible, resulting in a negligible effect.

Flora – Reduced Water Quality

16.5.39. Without mitigation, it is possible that construction activities, particularly removal of

topsoil and excavation, could lead to silt and pollutants entering the Red Rhine

on site, which contains aquatic and marginal plant species. A CEMP will be

implemented for the Proposed Development and associated infrastructure, which

will include storage of chemicals, plant movements, and protection of water

courses, as discussed in Chapter 13: Ground Conditions and Chapter 14: Flood

Risk, Hydrology and Water Resources of this PEI Report. Given these

measures, the magnitude of change resulting from run-off on flora is considered

to be negligible and effects are negligible.


May 2014 Page 16-41

Other Species

16.5.40. Effects on amphibians, water voles, badgers, aquatic and terrestrial invertebrates

will be assessed following completion of baseline surveys and reported in full in

the ES.

Operational Phase

16.5.41. The following changes associated with operation of the completed scheme have

the potential to affect ecological receptors:

• Loss of habitats through permanent landtake, and effects on species that

utilise these habitats. Such changes could be direct due to occupation of

land by the operational site, or indirect by reducing or causing

fragmentation of available habitat in the wider area;

• Disturbance to sensitive species through noise and visual impacts of

operational activities;

• Pollution of water bodies through emissions from the operational power

station;

• Air quality reductions through emissions from the operational generating

station. Such effects can be direct, in terms of physical changes to

habitats, with direct and also indirect effects on species that rely on such

habitats;

• Effects on ecological receptors from atmospheric emissions from

vehicles moving to and from the site. Such effects can be direct in terms

of physical changes to habitats, with direct and also indirect effects on

species that rely on such habitats.

16.5.42. The operation of the proposed cooling water pipeline and electrical connection is

not expected to have any ecological implications, and hence is not discussed

further.

Designated Sites - Permanent Land Take

16.5.43. There will be approximately 8.5ha of permanent land take associated with the

Proposed Development within the Generating Station Site, primarily focused in

the western part of the Site where the Generating Station will be located. None of

this would take place on sites designated for wildlife interest, either statutory or

non-statutory.

16.5.44. There would be potential for the loss of habitat to indirectly affect designated

sites through displacement of birds from supporting habitat that exists onsite.

Although the Proposed Development Site has value for species that form part of

an assemblage of waterfowl for which the Severn Estuary SPA and Ramsar sites


May 2014 Page 16-42

are designated, cumulative numbers of relevant species recorded onsite during

surveys in 2012 and 2013 did not exceed greater than 1% of the total

assemblage for which the designated sites qualify.

16.5.45. Numbers of snipe recorded onsite however were notable in the context of the

population of the Severn Estuary SSSI, for which the species is listed in the

citation. In combination with temporary landtake and disturbance, permanent loss

of habitat on the Proposed Development Site is likely to cause the displacement

of snipe onto other areas. The effect of this displacement is difficult to predict,

but is likely to cause either a Low or Medium change depending on the carrying

capacity of the receiving sites. Indirect effects on the Severn Estuary SSSI are

thus considered to be minor adverse.

Designated Sites - Disturbance

16.5.46. Disturbance of species which form a component of the Severn Estuary SPA,

Ramsar, SSSI or other non-statutory SNCIs could potentially occur through

increased lighting, visual presence or noise surrounding the operational site. The

nearest designated sites lie over 400m to the west and there is already

intervening infrastructure and visual, noise and light exposure of receptors. The

magnitude of change through disturbance on designated sites is considered to be

Very Low/Negligible, resulting in an effect of negligible significance.

Designated Sites - Reduced Water Quality

16.5.47. The Proposed Development will not require abstraction of water from the Severn

Estuary and there will be no direct discharge of water into the Severn Estuary. All

water necessary for cooling of the power station will be taken from and returned

to the Bristol WWTW. The magnitude of change is therefore considered to be

Very Low/Negligible, resulting in an effect of negligible significance.

Designated Sites - Air Quality

16.5.48. As part of the HRA, Environment Agency guidance (Ref. 16-7) suggests that

SACs, SPAs, and Ramsar sites up to 10km distant should be assessed. The

Proposed Development, when operational, will emit known pollutants to air, via

stacks. These will include the combustion products nitrogen oxides, carbon

monoxide and (for the short periods when distillate firing may be used) particulate

matter and sulphur dioxide. The ecological receptors assessed are all predicted

to result in NOX concentrations below the threshold for insignificance for daily and

annual mean critical levels, as shown in Chapter 11: Air Quality. Therefore it is

concluded that there will be a negligible effect of air quality on the designated

sites, leading to a minor adverse effect on the Severn Estuary SAC/SPA/Ramsar,

and SSSIs, and a negligible effect on LNRs and non-statutory sites.


May 2014 Page 16-43

Habitats on the Proposed Development Site - Permanent Land Take

16.5.49. Permanent land take will lead to the loss of 8.5ha of habitats, primarily semi-

improved grassland and tall ruderal habitat with small amounts of scrub, mature

trees and ditches potentially affected also. However, the development will include

6.4ha of landscaping, which will seek to replicate the habitats to be lost, and add

new features such as ponds, a swale and species rich grassland. Taking into

account the landscaping, the magnitude of change to habitats is considered to be

High, except on water courses as the Red Rhine diversion means that this

feature will still be present on site. Given the Low (Borough) value of the habitats

present the predicted effects are considered to be minor adverse.

Habitats on the Proposed Development Site – Hydrology and Groundwater

Quality

16.5.50. Land raising associated with the western part of the Proposed Development Site

have the potential for effects on the remaining drainage network both on and

adjacent to the Site. Run off from sealed surfaces will be attenuated through the

pond feature in the central portion of the Site. An assessment of effects on

surface and groundwater bodies within and adjacent to the Site is presented in

Chapter 13: Ground Conditions. With appropriate mitigation, the predicted effects

are considered to be negligible.

Habitats on the Proposed Development Site – Air Quality

16.5.51. As with offsite habitats, the magnitude of change associated with air quality

onsite is considered to be Low, and the effect is therefore negligible.

Bats (Roosting and foraging) – Landtake

16.5.52. The group of three mature trees considered to have potential for bats will be lost

due to permanent landtake. However, there will be tree planting within the

landscaping areas for the Site, which will increase the availability of bat roosts in

the long term. Bat boxes will also be installed on planted trees to increase the

availability of roosting habitats. The impact on roosting bats will be Low and

beneficial. The permanent loss of the existing Red Rhine corridor, with the

established areas of scrub and semi-improved grassland associated with it, will

reduce the value of the site for foraging bats. Replacement habitats will be

incorporated into the landscaping for the scheme. The overall impact is

considered to be Low and due to the Low (Borough) value of the receptor the

overall effect will be negligible.

Bats (Roosting and Foraging) - Disturbance

16.5.53. There is potential for disturbance to bats during the operation of the Site due to

lighting and noise. There will be permanent lighting within the Site which has the


May 2014 Page 16-44

potential to disrupt bat foraging routes and behaviour. Fast flying species, such

as common and soprano pipistrelle, noctule and serotine, which feed on insect

prey attracted to lighting may become more numerous. Slower flying species

such as Brandt’s bat may be discouraged from foraging nearer lit areas. Overall

the effects of lighting are considered to be negligible given the existing industrial

setting of the area including the adjacent Seabank 1 & 2.

16.5.54. No noise assessment is available for receptors within the Proposed Development

Site boundary, although an assessment has been made at Chittening Wharf,

400m to the west on the Severn Estuary. Night time noise levels at this receptor

are expected to increase by between 1 and 2dB depending on whether the single

shaft or multi-shaft option is selected. Effects on bats are therefore considered to

be negligible.

Breeding Birds - Landtake

16.5.55. Permanent landtake will lead to the loss of nesting habitat for scrub and ground

nesting species such as song thrush, linnet, skylark and lapwing. There is

available habitat for these species in the wider landscape. Therefore the impact

is considered to be Low, and the effect on breeding birds is negligible.

The turbine and HRSG building will be fitted with nesting platforms and boxes

suitable for peregrine falcon as they are known to utilise the Site currently for

perching and hunting, assuming they are still in the area at the start of

construction (currently forecast to be 2017). Peregrine nest boxes will generally

be located above 25-30m height above ground and north- or east-facing.

Non-Breeding Birds - Landtake

16.5.56. The habitat is also of value to non-breeding species, in particular snipe, which is

a species specifically listed in the SSSI citation. Although grassland and scrub

habitats will be incorporated into the layout of the Site, these are not considered

to offer suitable habitats for snipe, which require large areas of seasonally

flooded grassland which are free of disturbance.

16.5.57. The Severnside & Avonmouth Wetland Habitat Project (Ref. 16-7) identified that

the ‘loss’ of wetland habitats within the footprint of the 1957/58 Planning Consent

Area would be expected to result in a reduction in foraging (and potentially

roosting) opportunities for snipe, possibly leading to associated displacement

effects. Dependent on extent of development in the area, it was suggested that

further losses of habitat arising as a result of the 1957/58 Severnside Consent

could lead to associated reductions in the overall carrying capacity of these

areas, which could result in the displacement of common snipe from the

Severnside area.


May 2014 Page 16-45

16.5.58. The CCR Site will be reinstated following completion of construction activities,

although this is likely to support dry neutral grassland which may be of value to

ground nesting species such as skylark. It is not expected that it would be

reinstated to the existing marshy grassland, which was of value to snipe. The

proposed management of the CCR Site will be described in the landscape and

biodiversity masterplan, which will be produced as part of the final ES however it

is clear in the national guidance that the CCR Site would not be allowed to

enhance through neglect and some level of active management will be required..

16.5.59. The effects of temporary and permanent landtake on non-breeding birds,

specifically snipe, is considered to be moderate adverse, and therefore

significant without mitigation. However this is based on the site conditions pre-

December 2013 however, which no longer exists onsite; based on the current

baseline the effect is minor adverse, however it is not known whether the third

party developers currently working onsite will choose to reinstate the site to its

current value. Regardless, the Applicant is willing explore opportunities to

contribute to the management of land off-site for the benefit of bird interests in

the Severnside area to reduce this effect to minor adverse significance.

Breeding and Non-breeding birds - Disturbance

16.5.60. The visual presence of the Proposed Development, and light and noise

generation could lead to avoidance of habitats surrounding the site by bird

species. However, given the levels of industrial activity in the immediately

surrounding area, and the availability of suitable habitat for species in the wider

landscape, the magnitude of change in species abundance or diversity is

considered to be ‘Low and effects are considered to be negligible for breeding

species and minor adverse for non-breeding species.

Reptiles – Landtake

16.5.61. The Proposed Development Site currently supports a medium population of

reptiles. Approximately 8.5ha of habitats, primarily semi-improved grassland and

tall ruderal habitat with small amounts of scrub would be lost to permanent

landtake and these are habitats of value to reptile species known to be present

on the Proposed Development Site. Impacts of permanent landtake are

considered to be Medium, and the effects are therefore predicted to be minor

adverse.

Reptiles - Disturbance

16.5.62. Operational site activity is not considered to have potential to disturb reptiles

within areas of grassland and scrub. The impact is considered to be Very

Low/Negligible, leading to a negligible effect.


May 2014 Page 16-46

Flora – Landtake

16.5.63. The Proposed Development Site currently supports a low diversity of flora

species. Approximately 8.5ha of habitats, primarily semi-improved grassland and

tall ruderal habitat with small amounts of scrub would be lost to permanent

landtake within the Generating Station Site and therefore some common species

would be reduced in population size or lost. However, green and brown roofs as

part of enhancement of the Proposed Development Site will offer a more diverse

range of plant species on areas of permanent landtake. Impacts of landtake are

therefore considered to be negligible overall, and the predicted effect is

negligible.

Other Species

16.5.64. The effects on amphibians, invertebrates and mammals will be assessed once

baseline data sets are completed and reported in full in the ES.


16.5.65. The Proposed Development will have a minimum 30 year design life, with an

operational life that may be extended beyond that subject to its performance and

asset condition. The decommissioning process is expected to include removal of

structures on Site, although the cooling water pipeline would likely be left in situ

to avoid disturbance. There would be potential changes on ecological receptors

through disturbance, air quality and water quality during this process. The

baseline conditions cannot be accurately predicted at his stage, and the methods

of decommissioning are also difficult to predict. Given that the site would be

changing from an industrial, developed site, either to altered use, or

reinstatement to natural environment, it is considered likely that effects would be

neutral or beneficial to ecological receptors. The decommissioning phase is not

considered further in this report, given the uncertainties surrounding the

timescale of assessment and the likely associated effects.


16.6.1. Table 16-9 provides a summary of the predicted residual effects following

mitigation.


Receptor Construction Phase Operational Phase

Designated sites

Severn Estuary SAC/SPA/Ramsar

Minor adverse Minor adverse

Other designated sites Negligible Negligible

Habitats onsite

Landtake Minor adverse Minor adverse


May 2014 Page 16-47

Receptor Construction Phase Operational Phase

Species Bats Negligible Negligible

Breeding birds Minor adverse Negligible

Non-breeding birds Moderate adverse Minor adverse

Reptiles Minor adverse Minor adverse

Flora Negligible Negligible

Badger To be determined in the final ES

To be determined in the final ES

Water vole To be determined in the final ES


Otter To be determined in the final ES


Terrestrial invertebrates



Aquatic invertebrates To be determined in the final ES


Fish To be determined in the final ES


GCN To be determined in the final ES


16.6.2. The construction phase is anticipated to lead to a number of minor adverse

effects, as well as a moderate adverse effect on non-breeding birds, as

summarised below.

16.6.3. The northern end of the proposed cooling water pipeline corridor will pass within

approximately 140m of the SPA, Ramsar and SSSI, and noise levels during the

construction of the pipeline is expected to lead to a minor adverse effect on this

designated habitat, although the pipeline installation will be relatively rapid and

the disturbance therefore temporary in nature.

16.6.4. Temporary landtake will result in the loss of scrub and grassland habitats of value

for breeding and non-breeding birds in the eastern part of the Proposed

Development Site. The predicted effects on birds using this land are considered

to be moderate adverse (assuming the pre-December 2013 site conditions are

reinstated prior to enabling works for the Proposed Development), but with the

potential to reduce to minor adverse following offsite mitigation.

16.6.5. Construction activities have the potential to displace non breeding species such

as snipe and lapwing from the Proposed Development Site. When considered in

combination with the loss of habitat due to temporary landtake at the Proposed

Development Site, the suitability of the Site to support non-breeding birds will be

considerably reduced during construction. The impact of disturbance combined


May 2014 Page 16-48

with landtake is considered to be High and the overall effect moderate adverse,

reducing to minor adverse following offsite mitigation.

16.6.6. This conclusion is based on the baseline conditions assessed in this PEI Report.

However, given the extent of earth moving work and construction currently taking

place onsite to enable SITA’s Severnside Energy Recovery Centre, as well as

the Spine Access Road and realigned Red Rhine (see Chapter 7: Assessment

Methodology for a full description), it is expected that the revised baseline may

affect the significance of these effects associated with the Proposed

Development, reducing this to minor adverse significance. The revised baseline

will be assessed within the final ES.

16.6.7. The operational phase is not anticipated to lead to any moderate or major effects,

although a number of minor adverse effects have been identified. This includes

minor indirect effects on the Severn Estuary due to the potential disturbance to

and loss of habitat onsite for snipe, which may cause displacement of this

species onto other areas; this has resulted in a minor adverse effect being

assigned to both non-breeding birds and indirect effects on the Severn Estuary

SAC/SPA/Ramsar/SSSI habitat. The direct loss of habitats onsite, primarily semi-

improved grassland and tall ruderal habitat with small amounts of scrub, mature

trees and ditches, is also considered minor adverse following the reinstatement

of some areas and proposed landscaping strategy during operation.The visual

presence, light and noise generation of the operational Proposed Development

could lead to avoidance of habitats surrounding the site by bird species.

However, given the levels of industrial activity in the immediately surrounding

area, and the availability of suitable habitat for species in the wider landscape,

the operational effects once the CCR Site has been reinstated to grassland are

considered to be, at worst, minor adverse for non-breeding species.

16.6.8. The Site currently supports a medium population of reptiles, which appears to be

focused primarily around the scrub and grassland habitats associated with the

Red Rhine corridor and towards the northern edge of the Site. All of this habitat

will be lost to temporary landtake, although grassland habitat will be established

in the landscaped areas of the scheme, and there will be scrub within the

proposed swale corridor to the south of the CCR Site. However, these habitats

are much smaller in scale than under the current baseline, and will take time to

establish sufficiently to support a viable reptile population. This is anticipated to

lead to a minor adverse effect on reptiles.


16.7.1. This section considers the cumulative effects of the Proposed Development

along with other consented schemes within the vicinity, as listed in Chapter 7:

Assessment Methodology.


May 2014 Page 16-49

16.7.2. The mechanisms by which the Proposed Development and associated

infrastructure could potentially contribute to cumulative effects with these other

schemes are:

• Land take - loss of further habitat in the local area could, cumulatively

lead to pressure on supporting habitats for designated sites, and on

habitats of value for species identified during ecological survey works

at the Proposed Development Site.

• Disturbance – other consented works in the local area could lead to

further displacement of species that could already suffer disturbance

as a result of the Proposed Development Site.

• Air quality – other developments in the local area could contribute to

reduced air quality, in particular on roads that run within 200m of

designated sites, through increased emissions of pollutants from

vehicles.

• Water quality – other developments that would lead to discharges to

water courses that flow into the Severn Estuary could contribute to

cumulative loss of water quality.

16.7.3. In particular in the Severnside area, planning permission was granted for

industrial, office, warehouse and other ancillary uses on 1030ha of land at

Severnside in 1957 (hereafter referred to as the ‘1957/58 Severnside Planning

Consent’), which remains extant for future development. The review of the

1957/58 Severnside Consent has identified that up to approximately 456,900m2

of grazing pasture could be ‘lost’ under the future development footprint, based

upon a worst-case scenario.

16.7.4. The ecological assessments for the cumulative schemes have been reviewed to

identify the potential for significant cumulative effects. In particular, the following

was noted for the three cumulative schemes that identified as having significant

effects or requiring extensive mitigation or compensation:

• The ES for the ‘Deep Sea Container Terminal’ identified potential

moderate adverse effects for some species. However there is not likely

to be cumulative effects with the Proposed Development Site as the

habitat usage of the two sites by birds is different and any

displacement or disturbance of birds feeding on the foreshore would

lead to birds attempting to feed elsewhere on the foreshore and not

inland.

• The ES for the New Earth Solutions gasification plant identified the

need for a financial contribution to the Severnside and Avonmouth

Wetland Habitat project to mitigate adverse effects on protected


May 2014 Page 16-50

species and loss of habitat. This project is currently under construction

however and therefore the loss of this land already forms part of the

baseline rather than having the potential to lead to cumulative effects.

• The 1957/58 Consent included a requirement for setting aside 38ha of

land for ecology enhancements and the creation of green corridors.

The delivery of the ‘1957/58 development’ is not complete and hence

the ecological reserve has not yet been delivered, but it offers the

potential to reduce cumulative effects associated with landtake in the

wider area.

16.7.5. The gradual increasing re-industrialisation of Severnside, through the Proposed

Development and cumulative schemes identified in Chapter 7: Assessment

Methodology, has the potential to lead to a significant effect on bird species

associated with the Severn Estuary SAC/ Ramsar site, due to loss of wetland

habitat and disturbance. As identified above however, the Proposed

Development is only expected to have a negligible effect on this designated

habitat site, and the species for which it is designated have not been found to use

the Proposed Development Site. A moderate adverse effect has been identified

from the Proposed Development for non-breeding bird species, for which the

Severn Estuary SSSI has been designated. However this is based on the site

conditions pre-December 2013, which no longer exists onsite; the effect is only

considered minor adverse if the third party developers working onsite currently

choose not to reinstate the site to current conditions. The Applicant is wiling to

explore opportunities to contribute to the management of land off-site for the

benefit of bird interests in the Severnside area however to ensure this effect will

be of minor adverse significance.

16.7.6. It is not anticipated that there is the potential for cumulative effects related to any

other species or habitats. A minor adverse effect has been identified for reptiles,

but again, it is expected that the revised baseline for the final ES may affect the

significance of this effects, possibly reducing it to negligible significance. The

other effects associated with the Proposed Development are considered to be

negligible (or have not yet been determined) and are therefore unlikely to have

the potential to cause any cumulative effects.


16.8.1. It is likely that the baseline conditions will change between the preparation of this

PEI Report and the final ES. The Proposed Development Site is currently subject

to excavation, top soil stripping, and levelling in certain areas in order for third





May 2014 Page 16-51









16.8.3. At this stage, baseline data is also still being collected and therefore further

effects requiring mitigation may be identified following publication of this PEI

Report. These will be addressed as part of the final ES to be prepared for

submission in support of the DCO application. Enhancement measures that are

not essential for mitigation, but that would be recommended to accompany the

development on the Proposed Development Site have been described above.

16.8.4. The information in Table 16-10 below indicates the surveys that remain to be

completed in order to finalise the baseline for ecological receptors. Information

obtained from these surveys will be used to update this chapter for the final ES.

Table 16-10: Proposed Survey Requirements for the Final ES

Receptor Survey Required for Proposed Development Site

Survey Required for Other DCO Land

Habitats No further survey work is planned

A rapid habitat survey has been carried out along the proposed cooling water pipeline corridor to identify which protected species surveys are required; the Extended Phase 1 habitat survey for the pipeline corridor will be presented in the final ES.

Breeding birds

No further survey work is planned

Some of the proposed water cooling pipeline corridor also still requires completion of the breeding bird surveys. The results will determine whether avoidance or mitigation measures are required along the cooling water pipeline corridor in order prevent significant effects on bird species.

Amphibians No further survey work is planned

Amphibian surveys commenced in May 2013 and will be completed in April 2014. The results of pond surveys on the proposed water cooling pipeline corridor will determine whether there is a requirement to avoid water bodies in the vicinity of the pipeline route, or whether the works are likely to affect great crested newt terrestrial habitat within 500m of occupied ponds. Any works likely to affect GCNs may require a licence to be sought from Natural England in order to mitigate for effects on the


May 2014 Page 16-52

Receptor Survey Required for Proposed Development Site

Survey Required for Other DCO Land

European Protected Species.

Reptiles No further survey work is planned

Surveys of suitable reptile habitat on the proposed water cooling pipeline corridor will be undertaken during 2014 and reported in the final ES. The result will inform any mitigation required along the pipeline route, for example, trapping or exclusion of reptile populations.

Badgers Surveys will be undertaken for badger presence. The results will inform any mitigation required, for example, closure of active setts under Protected Species licence, creation of artificial setts, and installation of structures to ensure badgers are not trapped by any construction or operational features.

Water Vole Surveys will be undertaken for water vole presence. The presence of water vole along rhines may require mitigation in order to avoid adverse effects on the population. Works may need to avoid encroaching along the edges of the Red Rhine during construction for example. Prior to connection of the diverted Red Rhine channel, the new channel would need to be assessed as being suitable for water voles, assuming construction is complete in time for the final ES. Should this not be the case, any water voles present would need to be trapped under licence, introduced to a captive breeding programme, and only re-introduced once the replacement section of rhine is suitable.

Otter Surveys will be undertaken for otter presence and the results will be presented in the final ES. The presence of otter along the rhines might require mitigation in order to avoid adverse effects on the population. Works would potentially need to avoid encroaching along the edges of the rhines, particularly if any otter holts were identified.


Surveys will continue from those undertaken to date in order to provide invertebrate data over a full active season since spring surveys in 2013 were not undertaken.

16.9. References

Ref. 16-1 Institute for Ecology and Environmental Management (2006). Guidelines for Ecological Impact Assessment in the United Kingdom.

Ref. 16-2 Joint Nature Conservation Committee (2010). Handbook for Phase 1 habitat survey - a technique for environmental audit

Ref. 16-3 Institute of Environmental Assessment (1995). Guidelines for Baseline Ecological Assessment

Ref. 16-4 Parsons Brinckerhoff (2012). Seabank Power Station Extended Phase 1 Habitat Survey.

Ref. 16-5 Gilbert, G., Gibbons, D.W. & Evans, J.(1998). Bird Monitoring Methods. RSPB, Sandy.


May 2014 Page 16-53

Ref. 16-6 Environment Agency (2011). H1 Annex F – Air Emissions v 2.2.

Ref. 16-7 Cresswell Associates (2010). Severnside/ Avonmouth Wetland Habitat Project: Stage 1 – Distribution of Wetland Birds within the Study Area.

Seabank 3 PEI Report – Chapter 17 Landscape and Visual

May 2014 Page 17-1

17. Landscape and Visual

17.1. Introduction

17.1.1. This chapter describes the likely effects of the Proposed Development upon

landscape character and visual amenity of the DCO Site and the surrounding

area. The assessment is based on a thorough understanding of the baseline

conditions obtained through desk study and site visits. In addition to a

photographic record of the study area, a variety of published material has been

collected, as listed in the references section of this chapter.

17.1.2. An iterative assessment and design process has been followed which seeks to

reduce, offset or compensate for predicted effects on landscape character and

views. Mitigation is proposed to minimise significant adverse effects remaining

after that process and to seek to reduce residual impacts where possible.

17.1.3. The assessment makes use of photographs, which are referred to in the text to

assist in describing the character of the DCO Site and the wider study area and

existing views. Accurate, verifiable photomontages are used to describe the likely

visual effect of the Proposed Development on a series of representative views

which have been agreed with SGC and BCC. Photographs are also used in some

cases to explain where and why the Proposed Development is not likely to be

visible. Photographs used in this PEI Report were taken in early spring 2013 and

will be updated in the final ES.

Consultation

17.1.4. A Scoping Report was submitted to the Planning Inspectorate in February 2013

to allow stakeholders the opportunity to comment on the proposed structure, EIA

methodology and content of this chapter.

17.1.5. The Planning Inspectorate issued a formal Scoping Opinion in March 2013. A

summary of stakeholder comments and how they have been incorporated into

this PEI Report chapter are provided in Table 17-1.




The ES should describe the Zone of Theoretical Visibility (ZTV) provide information on the area covered and the timing of any survey work and the methodology used.

See section 17.2 and section 17.3

The ZTV should seek to ensure that all potential sensitive receptors are considered.



May 2014 Page 17-2


Consideration should be given to the need for landscape screening such as tree planting or bunding.

See section 17.5

SGC An overall landscape strategy should be included in the ES. The EIA should consider not only on site but any offsite mitigation that may be considered necessary

See section 17.5

A Landscape Strategy will also be necessary to cover associated development, such as pipelines, grid connections and access roads and access points.

See section 17.5

BCC No specific comments. -

NE The EIA should include a full assessment of the potential impacts on local landscape character using landscape assessment methodologies.


The landscaping scheme should be of a sympathetic design to break up views of the station as well as restore naturally occurring BAP habitats that have become degraded in recent years e.g. floodplain grass, hedges, reedbeds, open water.

See section 17.5

Gloucestershire County Council

The landscape character of the Forest of Dean District and the County of Gloucestershire should be considered as part of the South Gloucestershire's Landscape Character Assessment SPD.

See section 17.3

17.1.6. Following Scoping, a Technical Note was issued to SGC and BCC in March 2013

to agree the viewpoint locations and approach to the assessment. The agreed

viewpoints, locations from which photomontages would be produced, and

methodology are discussed in detail later in this chapter.


17.1.7. A summary of legislation and planning policy relevant to this assessment is

provided in Appendix C: Volume II of this PEI Report.


Overview

17.2.1. The method of landscape and visual impact assessment for the Proposed

Development has been devised to address the specific impacts likely to result

from a development of its scale and nature. The methodology draws upon the

following established best practice guidance:

• Guidelines for Landscape and Visual Impact Assessment 3rd Edition

(Landscape Institute and Institute of Environmental Management and

Assessment, 2013) (Ref. 17-1);


May 2014 Page 17-3

• Landscape Character Assessment: Guidance for England and Scotland

(Countryside Agency and Scottish Natural Heritage, 2002) (Ref. 17-2);

and

• Landscape Institute Advice Note 01/11: Photography and photomontage

in landscape and visual impact assessment (Landscape Institute, 2011)

(Ref. 17-3).

17.2.2. The assessment of impacts on built heritage, including impacts on the setting of

listed buildings, is covered in Chapter 15: Archaeology and Cultural Heritage of

this PEI Report.

17.2.3. Initial desktop study and site survey for the scoping report identified a study area

to a maximum of 10km from the boundary of the Proposed Development Site.

This range was considered a reflection of the maximum extent to which the

Proposed Development may materially influence the existing visual amenity and

allow views from across the Severn Estuary in Wales to be considered. In

contrast, a smaller study area of 5km from the boundary of the Proposed

Development Site is proposed for assessing landscape character. Beyond this

distance it is anticipated that the Proposed Development would be unlikely to give

rise to significant landscape effect. This study area was agreed with SGC and

BCC following Scoping.

17.2.4. A detailed study of the existing landscape components, character and views of

the DCO Site and the study areas has been carried out in consideration of the

following:

• Site context;

• Topography;

• Vegetation;

• Roads, public rights of way and access;

• Settlement and land-use;

• Landscape character; and

• Representative views.

17.2.5. This is supported by tables, drawings and photographs as appropriate. The

planning context with respect to landscape character and visual amenity has also

been assessed, taking into account relevant European, national, regional and

local planning policies. The baseline study forms the basis of the assessment of

the predicted impacts of the Proposed Development.


May 2014 Page 17-4

Terminology

17.2.6. This section provides an explanation of the terminology used throughout this

assessment:

• Landscape Character Areas (LCAs) are areas of relatively homogenous

landscape character. They are defined by the combination of elements

that contribute to landscape context, character and value. Typical

landscape elements include landform, land cover, vegetation and

settlement pattern. More subjective criteria are also considered such as

scale, unity and enclosure.

• Zone of Theoretical Visibility (ZTV) provides graphical representation of

places within the study area where the Proposed Development could

potentially be visible from. The ZTV is the area within which the Proposed

Development could have an influence or effect on visual amenity. ZTVs

are generated by computer by analysing a model of the Proposed

Development and a bare ground Digital Terrain Model (DTM), which might

or might not take into account the effect of vegetation and buildings.

• Visual receptors are special interest or viewer groups who would have

views of the Proposed Development. Visual receptors are identified

through interrogation of the ZTV and field work. As the study area for this

assessment is large, views for visual receptor groups are presented as a

series of photographs selected to best represent a range of views

selected from within the ZTV.

17.2.7. The EIA process requires that a clear distinction is drawn between landscape and

visual impacts:

• Landscape impacts relate to the degree of change to physical

characteristics or components of the landscape, which together form the

character of that landscape, e.g. landform, vegetation and buildings.

• Visual impacts relate to the degree of change to an individual receptor’s

view of that landscape, e.g. local residents, users of public footpaths or

motorists passing through the area.


May 2014 Page 17-5

Landscape Character Assessment Methodology

17.2.8. The assessment of landscape impacts has been structured around the

identification of LCAs. Within the 5km study area for landscape character

assessment it is possible to identify three categories of areas experiencing

different levels of impact: firstly there are areas where development would take

place resulting in direct effects; secondly there are areas where there is a degree

of intervisibility between the DCO Site and the surrounding landscape causing

indirect effects; and thirdly there are areas where no change would be

perceptible.

17.2.9. Each LCA has been assigned a sensitivity based on the character and quality of

the existing landscape and its ability to accommodate change. Sensitivity of LCA

is classified as Very High, High, Medium or Low, as follows:

• Very High: landscape of unique components and characteristics, sensitive

to any change;

• High: landscape of relatively distinctive components and characteristics,

sensitive to small changes;

• Medium: landscape of relatively common components and characteristics,

reasonably tolerant of changes; and

• Low: landscape of relatively inconsequential components and

characteristics, the nature of which is potentially tolerant of substantial

change.

17.2.10. The magnitude of potential change is determined through a combination of the

size/scale of the development, the geographical extent of the area influenced, the

type of development, the level of integration of new features with existing

elements, and its duration and reversibility. Magnitude of potential change is

classified as High, Medium, Low, or Neutral, as follows:

• High: ranging from a limited change in landscape characteristics over an

extensive area influencing several LCAs, to an intensive change over a

more limited area;

• Medium: ranging from a limited change in landscape characteristics at the

scale of the LCA within which the project lies, to a moderate change in a

localised area;

• Low: a limited change in landscape characteristics at the level of the

immediate setting of the site and the site itself; and


May 2014 Page 17-6

• Neutral: no change discernible in any component.

17.2.11. The assessment also considers potential impacts on the designated landscapes

Registered Park and Gardens in the southeast of the 10km scoping area.

Visual Assessment Methodology

17.2.12. It is widely accepted that visual effects tend to decrease with distance. For the

purposes of this assessment, the extent of potential views within the study area

(i.e. within a radius of up to 10km of the Proposed Development for visual effects)

has been determined. The resulting ZTVs for both the HRSG building envelope

(maximum height 45m above the finished ground levels (up to 53.5m AOD)) and

the two main stacks (of 90m height or up to 98.5m AOD) of the Proposed

Development have been reviewed by desk study and fieldwork against the

following criteria in order to determine the selection of representative views which

form the basis of the visual assessment:

• Receptor function / activity;

• Distance from the Site;

• Topography and elevation;

• Degree and period of exposure;

• Designation of the viewing place; and

• Distribution of receptors.

17.2.13. Representative viewpoints cover a range of receptor groups and locations from

close, middle and long distance and have been selected to adequately illustrate

the effect of the Proposed Development. Viewpoints and the location of

photomontages of the Proposed Development have been discussed and agreed

with SGC and BCC.

17.2.14. Visual receptors (based on representative views) have been assigned a category

of sensitivity based on a combination of the activity and expectations of the

predominant receptor type (e.g. residents, recreation, work etc.) and the location,

context and importance of the existing view. Sensitivity of receptors is classified

as Very High, High, Medium or Low, as follows:

• Very High: activity resulting in an exceptional interest or appreciation of

the view (e.g. people visiting to appreciate a recognised view) and/or a

very high value of existing view (e.g. Viewpoint from scheduled

monument):


May 2014 Page 17-7

• High: activity resulting in a high interest or appreciation of the view (e.g.

residents or people engaged in outdoor recreation whose attention is

focussed on the landscape) and/or a high value of existing view (e.g. a

designated landscape or unspoilt countryside);

• Medium: activity resulting in a medium interest or appreciation of the view

(e.g. people engaged in outdoor recreation that does not focus on an

appreciation of the landscape) and/or a medium value of existing view

(e.g. suburban residential areas or intensively farmed countryside); and

• Low: activity resulting in a low interest or appreciation of the view (e.g.

people at work or motorists travelling through the area) and/or low value

of existing view (e.g. industrial areas or derelict land).

17.2.15. The magnitude of visual change is determined through a combination of the

degree of change to the view resulting from the Proposed Development, including

the extent of the area over which the changes would be visible, the period of

exposure to the view and reversibility. Magnitude of change is classified as High,

Medium, Low or Neutral, as follows:

• High: high degree of change to existing view (e.g. loss of characteristic

features) and/or high degree of exposure to view (e.g. close or open

views);

• Medium: medium degree of change to existing view (e.g. partial loss of

characteristic features) and/or medium degree of exposure to view (e.g.

middle-distance or partial views);

• Low: low degree of change to existing view (e.g. limited loss of

characteristic features) and/or low degree of exposure to view (e.g. long-

distance, interrupted or glimpsed views); and

• Neutral: no change discernible in existing view.

17.2.16. Accurate Visual Representations of the Proposed Development for representative

views (visual receptors) have been produced in line with the Landscape Institute

guidance (Advice Note 01/11) (Ref. 17-3)

Temporal Assessment

17.2.17. The potential effects of the Proposed Development upon the existing (baseline)

landscape character, and receptors’ views of that landscape, have been

identified and assessed at three points in time:

• During construction (currently expected to be 2017 – 2021);


May 2014 Page 17-8

• On completion (currently expected to be 2021) – Year 1; and

• Following 15 years of operation (currently expected to be 2036) – Year

15.

17.2.18. Through the assessment of impacts at these stages, distinctions have been

drawn between temporary, permanent and residual impacts. Landscape and

visual effects are further categorised as being either direct (e.g. introduction of

built forms), or indirect (e.g. off-site visual impact of construction traffic).

Significance of Effects

17.2.19. Whilst there is inevitably a degree of professional judgement involved in

determining the levels of significance of landscape and visual effects, they can

broadly be determined by the interaction of the sensitivity of receptor and

magnitude of impact. This interaction results in categorisation of effects as shown

in Table 17-1. Effects are generally considered significant (and in need of

mitigation) if they are major or moderate.

17.2.20. Minor and negligible effects are not considered to be significant. A neutral

magnitude of change will always result in a negligible effect.

Table 17-1: Classification of Landscape and Visual Effects

Magnitude of Change

Sensitivity of Receptor


High Major Major Moderate Minor

Medium Major Moderate Minor Negligible


Neutral Negligible Negligible Negligible Negligible

17.2.21. Environmental effects are further identified as being either beneficial or adverse.

A textual description of landscape and visual effects is presented in Table 17-2.


May 2014 Page 17-9

Table 17-2: Description of Landscape and Visual Effects

Classification of Effect

Description of Landscape Effect Description of Visual Effect

Major beneficial effect

Where the Proposed Development would enhance the scale, landform and pattern of the landscape and/or enrich quality or characteristic feature

Where the Proposed Development causes a clearly significant improvement in the existing view

Moderate beneficial effect

Where the Proposed Development is characteristic of the scale, landform and pattern of the landscape, and/or enhances quality or characteristic features

Where the Proposed Development causes noticeable improvement to the existing view

Minor beneficial effect

Where the Proposed Development fits with the scale, landform and pattern of the landscape and/or quality or characteristic features.

Where the Proposed Development causes a slight improvement to the existing view

Negligible

Where the Proposed Development causes scarcely any perceptible deterioration or improvement to the existing landscape; or

No effect occurs.

Where the Proposed Development causes scarcely any perceptible deterioration or improvement to the existing view; or

No effect occurs.

Minor adverse effect

Where the Proposed Development does not fit with the scale, landform and pattern of the landscape and/or detracts from quality or characteristic features.

Where the Proposed Development causes slight deterioration to the existing view.

Moderate adverse effect

Where the Proposed Development is not characteristic of the scale, landform and pattern of the landscape, and/or damages quality or characteristic features

Where the Proposed Development causes noticeable deterioration to the existing view

Major adverse effect

Where the Proposed Development is at considerable variance with the scale, landform and pattern of the landscape and/or is considerably detrimental to quality or characteristic features

Where the Proposed Development causes a clearly significant deterioration in the existing view.


17.2.22. The exact layout and dimensions of the Proposed Development are not fully

determined at this stage; as such this assessment has been undertaken in line

with the Planning Inspectorate Guidance Note 9 ‘Using the Rochdale Envelope’

(Ref. 17-4).

17.2.23. The focus of the assessment within this chapter is to assess the worst-case

scenario, which, for landscape and visual effects, is typically considered to be the


May 2014 Page 17-10

maximum building sizes that may be consented under the scheme. However,

where the minimum parameters would affect the conclusions of the assessment

this is highlighted. For example, the peaking plant units may not be enclosed

within a building if OGCTs are selected, which would result in a structure that is

more industrial in appearance however noticeably smaller in footprint and height.

17.2.24. It is considered that the effects of anything less than the maximum parameters

would be similar to or less than the assessment presented in this chapter. This

should be the case for example if the final design incorporates only one stack for

example, rather than the two main stacks and two peaking plant stacks that have

been assessed.

17.2.25. The final design and appearance of the buildings and structures cannot be

finalised until detailed design has been undertaken, post consent and once the

Principal Contractor has been selected. The photomontages therefore present a

‘worst-case’ which reflects the maximum parameters to be consented under the

Rochdale Envelope, and with minimum design input (in accordance with the

Design Code which will be submitted as part of the DCO Application). They

therefore show no substantial architectural treatment.

17.2.26. To facilitate the reader’s interpretation of the information, the photomontages

illustrate the maximum parameters for both the single-shaft and multi-shaft

configurations.


17.3.1. This section describes the existing conditions onsite and in the surrounds, based

on a baseline situation pre-December 2013, as discussed in Chapter 2: The DCO

and EIA Process. It focuses on the Proposed Development Site, given that the

visual effects associated with the proposed cooling water pipeline and electrical

connection will be substantially less than for the Proposed Development.

Study Area and Site Context

17.3.2. The assessment considers the potential effects of the Proposed Development,

both in terms of changes within the Proposed Development Site and the Other

DCO Land, as described in Chapter 4: Project Description. Given the Other DCO

Land will constitute an underground water pipeline and a short length of electrical

connection (approximately 440m) within the Seabank 1 & 2 generating station,

the elements of primary interest in the context of the Landscape and Visual

impact assessment will take place within the Proposed Development Site.

17.3.3. The Proposed Development Site covers an area of approximately 19ha and is

located on land immediately adjacent to the existing Seabank 1 & 2 generating


May 2014 Page 17-11

station (illustrated in Figure 17-1, Volume III of this PEI Report). The Proposed

Development Site is approximately 5km northwest of Avonmouth in an area

called Crook’s Marsh in Severnside approximately 10km to the east of Bristol city

centre.

17.3.4. A detailed description of the site and surrounds is presented in Chapter 3: The

Site and Its Surroundings. A summary relevant to this assessment is presented

below.

Topography and Drainage

17.3.5. The topography of the 10km study area is illustrated in Figure 17-2, Volume III of

this PEI Report. The DCO Site is located within an area known as Crook’s Marsh

and is a flat open area of floodplain at approximately 5.5m and 7m AOD,

intersected by rhines (drainage ditches). To the west, the other side of the raised

embankment of the flood defence wall is the Severn Estuary. In contrast to the

east a north-south ridgeline, marks the edge of the marshland and floodplain,

beyond which to the east are the rolling hills of Bristol and Gloucestershire. The

Welsh hills are evident to the west on the far side of the Severn Estuary.

17.3.6. To the south the floodplain continues to the mouth of the River Avon, which forms

a dramatic gorge as it passes through the rolling hills of Bristol to the southeast.

South of the River Avon, the floodplain is less defined with low hills forming

shallow cliffs to the estuary as it widens out into the sea to the southwest.

Vegetation

17.3.7. The DCO Site lies in an area of flat agricultural floodplain which is pasture if

used. Within this area there are relatively few areas of trees and shrubs with only

a few remnant hedgerows and patches of scrub scattered across the landscape.

Away from the agricultural floodplain, several of the near-by recent industrial

developments have included significant areas of landscape. This includes the

Western Approach Distribution Centre to the north and the existing Seabank 1 &

2 generating station. Both have sought to enhance local habitats by planting

native trees and shrubs along realigned rhines and sustainable drainage systems

to recreate pockets of the natural landscape of the area. Other local

developments have adopted more modest landscapes of trees and shrubs within

amenity grass.

17.3.8. Woodland is more common on the ridgeline to the east. A mosaic of farmland,

historic parkland, woodland and urban development covers the ridge and the hills

to the east.


May 2014 Page 17-12

Transport Links

17.3.9. The Proposed Development Site lies in an area surrounded by several major

roads including the M49 Motorway link approximately 1km to the south and east,

the A403 (between Avonmouth and Severn Beach) approximately 400m to the

north and west, the M5 2.2km to the south and east, and the M4 approximately

7km to the north and east. The Severn Bridge linking England to Wales is

approximately 3km to the north and the Severn Road Bridge 7.5km the north.

17.3.10. A number of public rights of way are in the vicinity of the Proposed Development

Site, with the nearest ceasing at the southern boundary of the Site. The Severn

Way long distance footpath runs along the A403 to the west and The Community

Forest Path is along the ridgeline to the east.

17.3.11. Local train lines and stations are discussed in Chapter 10: Traffic and Transport.

Settlement and Land Use

17.3.12. The surrounding area between Avonmouth and Severn Beach (along the A403)

is in mainly industrial use, home to numerous chemical and pharmaceutical

works, industrial parks and distribution centres. There are few residential

properties in the area with a ring of settlements 2km from the Proposed

Development Site to north, east and south. These include Severn Beach, Marsh

Common, Compton Green, Berwick and Hallen. Other nearby settlements are

Pilning, 2.2km to the northeast, and Easter Compton 3km to the east.

17.3.13. The Proposed Development Site is surrounded by existing and proposed

development. To the southwest of the Proposed Development Site is the existing

Seabank 1 & 2 generating station, which was constructed on the site of gas

works that was built in the 1980s. Two wind turbines have recently been

constructed to the southwest of Seabank 1 & 2. To the north is the demolished

former ICI / Terra Nitrogen works, on which another developer has aspirations for

a separate power station. To the northwest a third party is currently building the

Severnside Energy Recovery Centre and Bottom Ash Facility. To the northeast, a

large area known as Central Park is being developed for a number of distribution

warehouses. To the southeast of the CCR Site is the Avonmouth LNG Storage

Facility.

17.3.14. Development under construction or with planning consent will be discussed in the

section Cumulative Effects. A list of these cumulative projects is provided in

Chapter 7: Assessment Methodology.

17.3.15. Apart from industrial and commercial development, the surrounding area is a mix

of agricultural land, small pockets of woodland along the ridgeline and scrub and

mudflats along the shoreline of the River Severn.


May 2014 Page 17-13

17.3.16. The area is crisscrossed by numerous pylons carrying overhead power lines

which together with other industrial infrastructure are key characteristics of the

landscape. Within the Proposed Development Site, there are pylons carrying

11kV, 132kV and 400kV overhead electrical lines crossing the CCR Site. Two

underground gas mains and a water pipe run along the southerly edge of the


Landscape of the DCO Site

17.3.17. The existing DCO Site is illustrated in Figure 17-3 (Volume III of this PEI) and

photographs (taken in August 2012) on Figures 17-4 and 17-5 (Volume III).

Figure 17-6 illustrates the local landscape character areas which are discussed

below.

Landform and Drainage

17.3.18. The DCO Site is generally flat, with some mounding in places. This mounding

may possibly result from clearance of previous development or to protect the

development from flooding on adjacent land. The Red Rhine runs along the

southern boundary of the CCR Site and through the centre of the Generating

Station Site, in an east to west direction. Other minor rhines are scattered

through the Proposed Development Site and DCO Site. These all drain the land

and feed into the River Severn to the west.

17.3.19. The Red Rhine is currently being realigned to run along the northern boundary of

the Proposed Development Site by a third party, Severnside Distribution Land

Ltd, as discussed in Chapter 7: Assessment Methodology. The same developer

is also currently constructing a Spine Access Road immediately north of the

realigned Red Rhine.

Vegetation

17.3.20. The flat open floodplain of the DCO Site is predominantly rough pasture broken

up into a rectangular field pattern by rhines (drainage ditches).

17.3.21. Patches of scrub are scattered across the Proposed Development Site,

particularly in the northern part and beside the rhines. Trees are few with only the

occasional relatively stunted specimen and a small area of trees and shrubs on

the edge of the Proposed Development Site beside the southern boundary. The

area has a neglected feel suggesting the pasture is not used for regular grazing.

Landscape Character

17.3.22. The character of the landscape of the 5km study area has been extensively

studied at a number of levels. In order to provide context to the Proposed


May 2014 Page 17-14

Development this section reviews and summarises the existing published

landscape character assessments at the national and local levels. In the Potential

Effects and Mitigation Measures section of this chapter the effects of the

Proposed Development are then assessed against LCAs defined at a local level

specifically for this assessment.

National Landscape Character

17.3.23. At the national level LCAs within the study area have been described based on

National Character Areas (NCA) defined and described by Natural England.

Whilst providing landscape context, NCAs do not provide sufficient detail on

which to assess the impact of the Proposed Development.

17.3.24. NCAs divide England into 159 natural areas each defined by a unique

combination of landscape, biodiversity, geodiversity and economic and cultural

activity.

Severn and Avon Vales NCA 106

17.3.25. The DCO Site is located within the Severn and Avon Vales NCA 106 (Ref. 17- 5)

and has the following description:

“The lower valleys of the rivers Severn and Avon dominate this low lying

open agricultural vale landscape made up of distinct and contrasting vales,

punctuating the otherwise flat vale landscape. The M5 Motorway runs

through the centre and the eastern edge of the area. A small proportion of

the National Character Area (NCA) is urban and industrial development is

still important at Avonmouth The majority of the area is used as agricultural

land. Woodland is sparse and it is a generally open landscape.”

17.3.26. Key characteristics of relevance are:

• “Fields on the floodplains are divided by ditches (called rhines south of

Gloucester) fringed by willow pollards and alders.

• Pasture and stock rearing predominate on the floodplain

• Along the main rivers, floodplain grazing marsh is prevalent.

• The River Severn flows broadly and deeply between fairly high banks,

north to south. The main rivers regularly flood at times of peak rainfall.”

Bristol, Avon Valleys & Ridges NCA 118

17.3.27. To the east of the DCO Site, the ridges and hills around Bristol are within NCA

118 – Bristol, Avon Valleys and Ridges (Ref. 17- 6). This NCA extends from the


May 2014 Page 17-15

Severn and Avon Vales to the west to the Cotswolds in the east. The landscape

is described as enclosed within an often gently undulating landform. The

hedgerow pattern is variable with woodlands mainly on steep valley sides.

Settlement is very dense, as many villages have become enlarged as commuter

settlements and have abrupt edges with the countryside. Key characteristics of

relevance to the study area are:

• “A landscape of very mixed landform, geology and settlement pattern,

strongly influenced by the Avon Valley, Bristol at its centre and by its

industrial history.

• Frequent large villages, small towns and major conurbations but also

undisturbed rural areas.

• Wooded scarps – with ancient woodland – and high, open, downland

ridges.

• Frequent parks, mansions and manor houses.”

Local Landscape Character

17.3.28. A district landscape character assessment covers the northern part of the 5km

study area within South Gloucestershire. The South Gloucestershire Landscape

Character Assessment (2005) (Ref. 17-7) is currently under review with a draft

review published in January 2014 (Ref. 17-8). For the purposes of this

assessment the 2005 assessment has been used, although the assessment has

noted proposed changes in the draft review where it has a bearing on the

potential effects and mitigation measures.

17.3.29. No similar district wide assessment is available for Bristol City and for the

purposes of this PEI Report LCAs have therefore been defined for the part of the

study area within Bristol City.

17.3.30. The 5km study area does not extend into North Somerset District,

Monmouthshire, Forest of Dean District and the County of Gloucestershire.

Landscape character assessments relevant to these areas are not considered in

this assessment.

17.3.31. Table 17-3 provides a summary of the local LCAs within the 5km study area and

descriptions of each LCA are provided in Appendix L Part 2, Volume II of this PEI

Report. Each LCA has been renumbered 1 to 8 and assigned a sensitivity based

on the district assessment and site survey.


May 2014 Page 17-16

Table 17-3: Summary of Local Landscape Character

EIA LCA Number LCA Name Sensitivity

LCA 1 Pilning Levels Medium

LCA 2 Severn Ridges High

LCA 3 Patchway and Filton Medium

LCA 4 Henbury and Kingsweston High

LCA 5 Hallen Marsh Medium

LCA 6 Avonmouth Low

LCA 7 River Severn Very High

LCA 8 Severn Shoreline and Estuary Very High

Summary of Landscape Character

17.3.32. The DCO Site falls within NCA 106: Severn and Avon Vales defined by Natural

England. To the east, NCA 118 Bristol, Avon Valleys and Ridges whose rolling

hills contrast sharply with the flat floodplain landscape of the vales to the west.

This distinct change in landscape character is reflected in the local landscape

character as defined by SGC and within the EIA defined landscape character

assessment.

17.3.33. The Proposed Development Site is located within LCA 1 Pilning Levels,

described as “a flat, semi-enclosed to open agricultural landscape, divided by

rhines, transport routes and punctuated by large industry.” To the east, LCA 2

Severn Ridges rises from the level ground to create an area of low hills and

radiating ridges. The flat floodplain landscape of the levels continues to the south

within LCA 5 Hallen Marsh and LCA 6 Avonmouth but increasingly is dominated

by large industry. The Severn Ridges also continues to the south within LCA 4,

Henbury and Kingsweston but is increasing dominated by residential

development closer to Bristol City Centre.

17.3.34. Both NCA 106 and LCA 1 are strongly influenced by the presence of the tidal

River Severn and estuary to the west. The extensive, open landscape of tidal

wetlands, mudflats and rock creates a constantly changing shoreline within

characteristic expansive views.

17.3.35. The landscape character of the 5km study area is varied comprising a number of

different landscape types. Sensitive landscapes are dispersed throughout, with

the wooded ridge landscape of the Severn Ridges to the east, the estuary

landscape of the River Severn to the west and the remnants of agricultural

floodplain landscape of the Levels in the centre. To the east and west, landscape

features often remain intact within these areas, however, the landscapes suffer

from development usually outside the area, interrupting views and disturbing


May 2014 Page 17-17

tranquillity. The influence of the major transport routes, industry and urban areas

on the surrounding landscape is obvious, compartmentalising it into distinct areas

between transport routes and landform.

17.3.36. Located beside the existing Seabank 1 & 2 generating station and the recently

demolished ICI / Terra Nitrogen works, the Proposed Development Site is

currently unused and grassland. It is criss-crossed by pylons carrying overhead

power lines and pipelines with rough grassland and patches of scrub. Coupled

with the tall chain link fencing bounding the Proposed Development Site, fly

tipping and other signs of disuse, the area appears abandoned.

Visual Amenity

Visibility within the Study Area

17.3.37. ZTVs of the proposed HRSG building envelope and two stacks (90m height) have

been generated by computer modelling as depicted in Figures 17-7 and 17-8

(Volume III of this PEI). The effect of existing buildings and groups of trees and

shrubs has not been included. The percentage visibility of parts of the stacks has

also been considered within the 10km study area.

17.3.38. Individual receptors with possible views of the Proposed Development have been

identified within the proposed ZTVs and verified by on-site survey. The receptors

have been allocated to receptor groups according to their sensitivity (Very High,

High, Medium or Low) to changes in visual amenity. A schedule of visual

receptors is included in Appendix L, Part 2, Volume II of this Report.

17.3.39. Table 17-4 provides a summary of the representative views and visual receptors.

Table 17-4: Visual Receptors and Representative Views

Receptor Number and Name Sensitivity Representative View Number and Name

1a. Users of PROW beside the River Severn

Medium Representative View 1 - View from the river bank at Caldicot looking southeast

1b. Travellers crossing the Severn Bridge

Low

2a. Travellers using Holloway Road

Low Representative View 2 - View from Holloway Road bridge as it crosses over M49 looking southwest 2b. Workers in warehouses along

Holloway Road Low

3a. Users of Community Forest PRoW crossing over the M5

Medium Representative View 3 - View from bridge carrying Community Forest Path over M5 looking northwest

4a. Users of Community Forest PRoW as it travels along the ridge of Spanorium Hill

Medium Representative View 4 - View from Community Forest Path as it crosses Spanorium Hill looking northwest


May 2014 Page 17-18

Receptor Number and Name Sensitivity Representative View Number and Name

5a. Users of Blaise Castle public park

Medium Representative View 5 - View from beside Blaise Castle looking northwest

6a. Users of PROWs through Kingsweston public park

Medium Representative View 6 - View from footpath leading up to Kingsweston House looking north 6b. Users of Kingsweston House Medium

7a. Travellers crossing the Severn Road Bridge (M48)

Low

Representative View 7 - View from footpath crossing Severn Road Bridge (M48) looking south

7b. Users of PROW crossing the Severn Road Bridge (M48)

Medium

8a. Residents in properties along riverfront at Portishead

High

Representative View 8 - View from promenade along riverfront at Portishead looking northeast

8b. Users of promenade at Portishead

Medium

9a. Travellers along the A403 Low

Representative View 9 - View from pavement running along A403 looking southeast

9b. Users of PROW along the A403 and cyclepath

Medium

10a. Users of PROW crossing Crook’s Marsh

Medium Representative View 10 - View from PROW crossing Crook’s Marsh looking northwest

11a. Users along the Severn Way PRoW

Medium Representative View 11 - View from Severn Way along river wall at Severn Beach looking south 11b. Residents in properties along

the riverfront at Severn Beach High

17.3.40. Descriptions of the views for each visual receptor are provided in Appendix L,

Part 2, Volume II of this Report and illustrated by means of photographs taken

from 11 representative viewpoints.

17.3.41. The locations of the representative viewpoints are illustrated in Figure 17-8

(Volume III of this PEI), and the photographs are included in Figures 17-9 to 17-

14 (Volume III). These have been located at publicly accessible vantage points to

represent as closely as possible the actual view for each receptor. Where

possible, the actual view is presented but otherwise, when for example

intervening vegetation blocks views, locations have been chosen at nearby

gateways and gaps in vegetation to demonstrate the experience of the receptor

as if the vegetation was removed. In response to a request from SGC,

representative views have been located at Holloway Road, within the Western

Approach Distribution Centre (Representative View 2), the bridge over the M5


May 2014 Page 17-19

carrying the Community Forest Path (Representative View 3) and from the

Severn Way footpath at Severn Beach (Representative View 11).

17.3.42. Photomontages of the Proposed Development at Year 1 and following 15 Years

of Operation for three of the 11 representative views (Representative Views 4, 10

and 11) have been produced and are discussed in the following section, Potential

Effects and Mitigation Measures. Both options, the single-shaft and multi-shaft

development, are shown on separate photomontages. These are presented in

Figures 17-16 to 17-30 (Volume III of this PEI) and their locations indicated on

Figure 17-8 (Volume III). Viewpoints and the location of photomontages of the

Proposed Development have been established in consultation with SGC and

BCC.

Summary of Baseline Views

17.3.43. The Proposed Development Site is located within the flat open landscape of the

Pilning or Severn Levels with open direct views across the area from high ground

to the east. In contrast, the flatness of the landform restricts visibility from the

north, south and west with vegetation and development screening the majority of

direct views at ground level.


17.4.1. The design of the Proposed Development is largely based upon the technical

requirements of the scheme, however informal consultation responses in respect

to the finishes of the Proposed Development have been taken into account.

17.4.2. Chapter 6: Project Need and Alternatives provides an explanation of the design

evolution to take into account the need for landscaping onsite. In particular, the

cooling water systems were realigned during the later stages of development to

enable the turbine buildings and HRSG buildings to move south, enabling a row

of tall landscaping to be incorporated in the design along the northern boundary

of the Site.

17.4.3. An area of landscaping has also been integrated into the design along the

proposed PROW that connects Ableton Lane and the existing roundabout east of

the Proposed Development Site. Additional space was also made available in

later designs for tree planting between the peaking plant and CCR Site to break

up views from the east.

17.4.4. The final design may incorporate additional measures to mitigate landscape and

visual effects, such as green or brown roofs and architectural treatment, as well

as minimising the building massing and heights; however for the purpose of this


May 2014 Page 17-20

assessment it was deemed appropriate to present the worst-case situation, as

discussed earlier.

17.4.5. As described in Chapter 4: Project Description, the electrical connection will be

routed through the Seabank 1 & 2 station on a cable rack approximately 2m

above the ground or buried underground for the 440m distance to Seabank

Substation. The avoidance of an overhead line and routing the line through

Seabank 1 & 2, where it will blend into the background of industrial structures, is

considered to fully mitigate the effects of the electrical connection.


17.5.1. The assessment of effects relies on field data collected during autumn 2012 and

winter 2013. Field surveys recorded existing baseline data and assessed the

likely impacts of the Proposed Development on the landscape character within a

5km radius of the DCO Site and for visual receptors within a 10km radius of the

DCO Site.

Construction Phase

17.5.2. The enabling works and construction of the Proposed Development is expected

to take approximately 54 months to complete, if built in a single phase. The

nature of construction means that impacts on the character of the surrounding

landscape and surrounding views are inevitable, albeit temporary in nature. The

construction of the Proposed Development would involve a number of activities

that have the potential to impact on landscape and views. These include the

following:

• Site clearance operations, including the removal of some existing

vegetation;

• Realignment of the Abson gas pipeline that currently runs through the

centre of the proposed development site;

• Raising of the ground level of the Generating Station Site and land re-

profiling to proposed contours by importing material into the Proposed

Development Site;

• Establishment and subsequent presence of a construction compound,

security fencing and temporary working areas throughout the construction

period;

• Traffic management signs and equipment;


May 2014 Page 17-21

• Construction of temporary haul roads and hard-standings and removal at

the end of the construction period;

• Excavation and temporary stockpiling of soils and demolition materials for

re-use, including along the proposed cooling water pipeline corridor;

• Construction machinery, plant and vehicles accessing and moving across

the Site;

• Passage of heavy construction plant and delivery vehicles on the local

road network;

• Erection and operation of temporary cranes, cement silos, scaffolding etc.;

• Civil engineering works, including construction of foundations, concrete

slabs, access roads and drainage;

• Construction of the steel building structure and subsequent cladding;

• Installation and commissioning of process plant items; and

• Service installations including pipe/cabling, electrical connection and

water pipe (further details are provided in Chapters 4 and 5).

Landscape Effects of Construction

17.5.3. The change during construction and the resulting effect is described for each

local LCA within the 5km study area in Appendix L Part 3, Volume II of this PEI

Report. The construction of the Proposed Development would result in a number

of direct and indirect effects on the landscape character of the 5km study area as

discussed below.

Direct Effects

17.5.4. LCA 1 would be directly affected by the construction of the Proposed

Development and proposed cooling water pipeline. The majority of the DCO Site

is located within the LCA and the existing rough grassland and scrub would be

replaced by construction activities. The change in character of the DCO Site

would be seen within the context of similar activity on adjacent industrial and

construction sites. The southern part of the LCA is characterised by industrial

developments and the construction works would follow this pattern.

17.5.5. In addition to construction works within LCA 1, the proposed cooling water

pipeline would be installed along the northern boundary of LCA 5. Again this area

is characterised by industrial development and though the construction works

would result in disturbance to the existing agricultural land, they again would be


May 2014 Page 17-22

in the context of other industrial developments and the numerous pylons with

overhead power lines and pipelines crossing the LCA. The works would be

comparable to small-scale road works and their character would reflect typical

maintenance that frequently occurs within the industrial context.

17.5.6. An increase in construction vehicle movements in LCA 1 and 5 away from the

DCO Site is also possible, although the likely relative impact of this would be

limited by the fact that the existing activities in Avonmouth and the surrounding

area already result in more vehicle movements than might otherwise be expected

on local roads.

17.5.7. LCA 1 and LCA 5 have a Medium sensitivity to change and the construction

phase would cause a Medium magnitude of change resulting in a minor adverse

temporary landscape effect, which is not considered to be significant.

Indirect Effects

17.5.8. Enabling works and construction activities would occur across the DCO Site over

an expected 54 month period. During that time, construction traffic may result in

increased vehicle movements in adjacent LCAs, in particular LCA 6. The open

nature of the DCO Site would increase potential for intervisibility between LCA 1

and adjacent LCAs. The flat landform of the surrounding area however results in

local screening from buildings and vegetation. This helps to limit intervisibility for

LCAs with a similar topography such as LCA 6 Avonmouth. The dense

development within LCA 6 reduces opportunities for intervisibility with LCA 1

except along the northern boundary. In addition, LCA 6 has an ever evolving

industrial character with construction works and associated traffic fluctuations

throughout the LCA. The Low impact of the construction phase on a LCA with a

Low sensitivity to change would result in a negligible landscape effect, which is

not considered significant.

17.5.9. In contrast, there is a high degree of intervisibility between LCA 1 and LCA 2,

Severn Ridges to the east of the DCO Site. Construction activities would be seen

as part of the characteristic expansive panoramic views of other industrial

developments and construction within the wider LCA 1. Beyond the western edge

of LCA 2, there would be no intervisibility with LCA 1, with the result that the

majority of LCA 2 would experience no indirect landscape impacts. LCA 2 has a

High sensitivity to change and would experience a Low adverse impact resulting

in a Minor landscape effect, which is not considered significant.

17.5.10. Landform and vegetation prevent intervisibility between LCA 1 with LCA 3, LCA

4, LCA 7 and LCA 8. Construction traffic would also not increase within these

LCAs, and as a result there would be no landscape impact, therefore resulting in

a negligible landscape effect.


May 2014 Page 17-23

Summary of Landscape Effects of Construction

17.5.11. Due to the nature, extent and duration of the construction activities and the

character of the existing landscape identified in the eight LCAs within the 5km

study area the landscape effects would range from negligible to minor, which are

not considered significant.

17.5.12. Direct effects on landscape character would be limited to the DCO Site and the

immediate area within LCA 1 and LCA 5. The effects would result from

construction activities across the whole of the Proposed Development Site and a

series of defined areas within the DCO Site. Construction activities would include

operation of plant and machinery, access roads, hard-standings and ground

modelling. Direct effects would be temporary and not significant.

17.5.13. Impacts on landscape character of the surrounding area would diminish with

distance from the DCO Site and the cumulative screening effect of intervening

features reducing intervisibility between LCAs. Indirect effects on adjacent LCAs

would be temporary and not significant.

Visual Effects of Construction

17.5.14. The likely effects on views during construction are described in Appendix L Part

4, Volume II of this PEI Report. The main effects are discussed below.

17.5.15. Though the DCO Site is open with a number of potential close range views there

are relatively few public vantage points. Where views are available, construction

activities on the DCO Site would be seen within the context of construction and

industrial activities on adjacent sites. The removal of the rough grassland, ground

modelling and gradual emergence of the Proposed Development would be visible

in close range views for travellers and walkers along the A043 (Receptors 9a and

9b) and for walkers on PROWs on Crook’s Marsh (Receptor 10a). Views of

construction from the A403 (Receptors 9a and 9b) would be filtered by the

construction works and eventual development on the Severnside Energy

Recovery Centre. The Medium magnitude of change would result in minor

adverse visual effect which is not significant. In contrast, views from Crook’s

Marsh (Receptor 10a) would be direct within only patches of scrub on adjacent

land filtering views. The High magnitude of change would result in a moderate

adverse visual effect which is considered significant, albeit temporary in duration.

17.5.16. Construction activities would also be visible in views from elevated locations.

Users of the Community Forest PROW on Spanorium Hill (Receptor 4a) would

see the works as part of an open panoramic view across the level ground. The

loss of agricultural fields to construction works would clearly be viewed within the


May 2014 Page 17-24

context of other construction and industrial activities within adjacent sites in the

surrounds. The distance of the receptor from the DCO Site, the nature of the view

and scale of the panorama would result in a Medium magnitude of change with a

minor adverse visual effect, which is not significant.

17.5.17. Views within the level ground away from the immediate vicinity of the DCO Site

are interrupted by buildings and vegetation. As a result only the tall construction

plant and eventually the top of the HRSG building, peaking plant and stacks

would be visible above these filtering features. Construction would result in a Low

visual change for receptors with middle distance views towards the Site, including

those within the Western Approach Distribution Park (Receptors 2a and 2b) and

in Severn Beach (Receptors 11a and 11b). Visual effects would vary from minor

adverse to negligible which are not significant.

17.5.18. Construction would not be readily apparent within distant views of the DCO Site.

Intervening features filter the views in all cases with only tall construction plant

and eventually the top of the HRSG building, peaking plant and stacks visible. In

addition, clarity of distant views is also frequently dependant on weather

conditions. The Low magnitude of change for receptors 1a, 1b, 6a, 7a, 7b, 8a

and 8b would result in a minor adverse or negligible visual effect, which is not

significant.

17.5.19. Three receptors (Receptors 3a, 5a and 6b) are enclosed by vegetation and

landform and would experience no views of construction on the DCO Site.

Summary of Visual Effects of Construction

17.5.20. Of the eighteen visual receptors identified in this PEI Report only one would

experience a significant adverse visual effect. Users of the PROW on Crook’s

Marsh (Receptor 10a) would have direct open views of construction activities on

the DCO Site. The activities would be seen within the context of other

construction work and industrial uses on adjacent sites. Though the construction

works would last an expected 54 months, construction activities are temporary

and would vary during this period. Gradually the disruption arising from

construction would be replaced with an organised industrial development similar

to adjacent developments.

Operational Phase

17.5.21. The following assessment of operational landscape and visual effects considers

changes to landscape character and visual amenity on completion of construction

of the proposed facilities in 2021 (Year 1) and 2036 (Year 15).

17.5.22. Photomontages of the Proposed Development at Year 1 have been produced

and are shown on Figures 17-16 to 17-30 (Volume III of this PEI Report). Their


May 2014 Page 17-25

locations have been established in consultation with SGC and BCC and are

illustrated on Figure 17-8 (Volume III of this PEI Report).

17.5.23. The operational effects of the proposed cooling water pipeline are not discussed,

given that it will be underground and therefore not visible. In addition, the

proposed electrical connection may also be underground, or at low level within

the existing Seabank 1 & 2 site. The operational effects of this associated

development are therefore considered to be negligible.

Landscape Effects (Year 1)

17.5.24. The likely effects at the start of operation for each local LCA within the 5km study

area are described in Appendix L Part 3, Volume II of this PEI Report. Key effects

are discussed below.

Operation: Direct Landscape Effects (Year 1)

17.5.25. LCA 1 would be directly affected by the completed Proposed Development. The

existing flat, floodplain landscape of rough grassland and scrub would be

replaced by a large scale power station. The scale and mass of the Proposed

Development located on the open Site would have a substantial impact on the

immediate landscape character of the Proposed Development Site. However the

context of the LCA within the Levels and LCA 6, Avonmouth to the south that

includes Seabank 1 & 2 and other industrial developments with their large

warehouse-style buildings, tall stacks and wind turbines reduces the level of

impact to Low. On completion the disruption of construction would be replaced by

a new industrial development with a well-conceived design and site layout in

keeping with the surrounding landscape character of both Pilning Levels (LCA 1)

and adjacent areas (LCA 6 Avonmouth and LCA 5 Hallen Marsh). The minor

adverse landscape effect on LCA 1 is considered not significant.

Operation: Indirect Landscape Effects (Year 1)

17.5.26. The Proposed Development would to some degree, extend the influence of the

existing industrial area in terms of intervisibility between LCAs. When operational,

the Proposed Development may result in an increase in number of vehicle

movements on local roads but this would be similar to the normal fluctuations

experienced in the Avonmouth area. Detail traffic considerations are discussed in

Chapter 10: Traffic and Transport.

17.5.27. LCA 2 Severn Ridges to the east has a High sensitivity to change and the

Proposed Development would cause a Low magnitude of change resulting in a

minor adverse indirect landscape effect, which is not considered significant.


May 2014 Page 17-26

17.5.28. LCA 5 Hallen Marsh and LCA 6 Avonmouth to the south also would experience a

Low level of change. Though the Proposed Development would be visible from

the northern part of both LCAs, buildings and vegetation within the LCAs would

limit intervisibilty. In addition the nature of the Proposed Development would

appear appropriate to its location. The negligible landscape effects are

considered not significant.

17.5.29. All other identified LCAs within the 5km study area have no intervisibility and

would experience no landscape effects.

Summary of Landscape Effects on Completion (Year 1)

17.5.30. Of the eight LCAs identified in the 5km study area only one would be directly

affected by the operation of the Proposed Development. The effect on landscape

character is considered not significant in the context of the adjacent industrial

area within the Levels. The Proposed Development would be carefully located

within the existing landscape framework of the floodplain and would introduce a

new industrial development in character with the surrounding industrial area.

17.5.31. Three LCAs would experience indirect landscape effects, none of which are

considered significant.

Visual Effects (Year 1)

17.5.32. The completed Proposed Development is expected to result in direct visual

impacts within the 10km study area as the varied (over the construction period)

and relatively disruptive (in visual terms) visual impact of the Proposed

Development Site during construction is replaced with the organised layout of the

new buildings, stacks and associated infrastructure. Photomontages of the

Proposed Development of both the single-shaft and multi-shaft option at Year 1

have been produced and are shown in Figures 17-16 to 17-30 (Volume III). Their

locations have been established in consultation with SGC and BCC and are

illustrated in Figure 17-8 (Volume III).

17.5.33. Proposed external lighting during periods of operation after dark would also result

in direct visual impacts. An outline of the lighting principles for the Proposed

Development is provided in Chapter 4: Project Description. An outline lighting

strategy will be provided in the final ES.

17.5.34. Intermittent, visual effects would be likely to result from a plume emanating from

the stacks, which could form under certain atmospheric conditions, principally

when the steam / hot air from the stacks enters cold, still air, leading to

condensation and visibility as a white plume. This is normally an early morning /

late evening or winter phenomenon. The potential plume would be variable in


May 2014 Page 17-27

extent and appearance or absent altogether. Further information is provided in

Chapter 11: Air Quality.

17.5.35. The likely effects on views within the 10km study area at Year 1 of operation are

provided in Appendix L Part 4, Volume II of this PEI Report. The main effects are

discussed below.

Close Views: up to 1km

17.5.36. The Proposed Development would be visible in views for users of the A403

(Receptors 9a and 9b). These would be interrupted by the buildings and

landscape of the existing Seabank 1 & 2 station and the Severnside Energy

Recovery Centre site (currently being developed). In addition, the tall HRSG

building and two stacks are proposed to be located to the southeast of the

Proposed Development Site at the furthest point from the A403. The buildings

and landscape of the Severnside Energy Recovery Centre site would assist in

reducing the perceived scale of the Proposed Development and screen low level

plant resulting in a Medium magnitude of change, which is considered a minor

adverse visual effect that is not significant.

17.5.37. Views for users of PROWs in Crook’s Marsh (Receptor 10a) would be more open

and direct with only small areas of scrub filtering views. Though woodland blocks

are to be planted as part of the Proposed Development along the southern

boundary, these would not have established sufficiently by Year 1 to reduce the

perceived scale of the structures within the Proposed Development Site or screen

low level plant. The Proposed Development would be seen however in the

context of other industrial developments on adjacent site as illustrated on Figures

17-22 (Volume III) and 17-24 (Volume III). The level of effect for Receptor 10a

would be High creating a moderate adverse visual effect, which is considered

significant.

Middle Distance Views: 1 to 5km

17.5.38. On completion, the Proposed Development would be seen as elements within the

panoramic views of the surrounds and the River Severn from the ridgeline to the

east. Users of the Community Forest Path on Spanorium Hill (Receptor 4a) would

see the Proposed Development located within the floodplain landscape of fields

and rhines and within the context of the other industrial developments within the

area as shown on Figure 17-17 and 17-19 (Volume III of this PEI). Planting along

the eastern boundary of the Proposed Development Site would not have

established by Year 1 of Operation to assist in reducing the perceived scale of

the Proposed Development or filter views of plant at low levels. The Medium

magnitude of change would result in a minor adverse visual effect which is not

significant.


May 2014 Page 17-28

17.5.39. In contrast views from the north from Holloway Road (Receptors 2a and 2b) and

from Severn Beach (Receptors 11a and 11b) would be interrupted by buildings

and vegetation in the foreground as illustrated on Figures 17-27 and 17-29

(Volume III). Only the upper parts of the Proposed Development would be visible

above these foreground features. The top of the HRSG building, peaking plant

and the two stacks would be seen within the context of other tall structures within

adjacent sites including the recently constructed wind turbines and Seabank 1 &

2. The Low impact would result in a minor adverse or negligible visual effect

which is not significant.

17.5.40. To the southeast, development, landform and woodland would interrupt views of

the completed Proposed Development. Glimpsed views may be possible through

gaps in the ridgeline and woodland but for users of Blaise Castle public park

(Receptor 5a) and the Community Forest Path crossing the M5 (Receptor 3a)

they would experience no views of the Proposed Development.

Long Distance Views: 5 to 10km

17.5.41. Due to the nature of the topography on the edge of the Severn estuary there are

numerous potential long distance views towards the Proposed Development from

the west. These views are however, distant and interrupted by foreground and

middle ground features. They are also dependant on weather conditions. Only

the upper parts of the Proposed Development would be visible, seen within the

context of similar industrial developments with tall stacks, wind turbines and large

building blocks. Often the Proposed Development would be difficult to identify

within these views. As a result, the impact on all identified receptors experiencing

a view of the Proposed Development (Receptors 1a, 1b, 6a, 7a, 7b, 8a and 8b)

would be Low resulting in minor adverse or negligible visual effect, which are

not significant.

Visual Effects of Lighting

17.5.42. The lighting strategy will be carefully considered to minimise light spill and sky

glow resulting from the external and internal lighting of the Proposed

Development. Low intensity steady red aviation warning lighting and colour

markings are proposed to be positioned as close to the top of the stacks as

practicable. Though these would be visible in dark skies these would be seen

within the context of other lighting on tall stacks and wind turbines and

operational lighting in adjacent industries. As a result the visual impact on visual

receptors would be low resulting in a range of minor adverse to negligible

visual effects, which are not significant.


May 2014 Page 17-29

Summary of Visual Effects on Completion (Year 1)

17.5.43. Upon completion of the Proposed Development, the relatively intrusive (in visual

terms) nature of the DCO Site during construction would be replaced with an

organised layout. Only users of PROWs on Crook’s Marsh (Receptor 10a) would

experience a moderate adverse significant adverse visual effect. The receptor is

within 1km of the DCO Site with open direct views. The Proposed Development

would be seen within the context of other industrial developments including the

recently constructed wind turbines and network of pylons and overhead power

lines.

17.5.44. All other identified visual receptors would experience minor adverse or negligible

visual effects, which are not significant.

Mitigation Measures

17.5.45. During construction all existing trees and shrubs to be retained (although this will

be limited) would be protected in accordance with BS 5837:2012 - Trees in

Relation to Design, Demolition and Construction. In addition:

• Suitable materials will be used, where possible, in the construction of

structures to reduce reflection and glare and to assist with breaking up the

massing of the buildings and structures; and

• Lighting required during the construction and operation stages of the

Proposed Development will be designed to reduce unnecessary light spill

outside of the site boundary.

Landscape Proposals

17.5.46. Landscape proposals are shown on Figure 17-15 (Volume III of this PEI). They

are intended to achieve the following objectives:

• To integrate the Proposed Development into the existing industrial

landscape of Severnside and the wider landscape character of Pilning

Levels;

• To break up the perceived scale of the buildings from nearby Public

Rights of Way and access roads;

• To create a wooded setting for the Proposed Development using native

species;

• To provide opportunities for habitat enhancement through natural

regeneration of ruderal vegetation; and


May 2014 Page 17-30

• To encourage wetland habitats to develop adjacent to on-site water

attenuation features including swales, and a pond, and also off site beside

the Red Rhine.

17.5.47. To fulfil these objectives the landscape proposals are to:

• Establish substantial native species woodland blocks to the north and

south of the new power station;

• Retain and incorporate existing trees and shrubs into the woodland

blocks;

• Link woodland blocks through trees and shrub belts, to maintain

ecological connectivity;

• Define entrances into the Proposed Development through structural

planting;

• Develop suitable conditions to encourage large areas of ruderal

vegetation to grow, especially along the banks of the recently relocated

Red Rhine and swales along the southern boundary;

• Form new balancing pond with series of wetland and aquatic habitats,

interconnected with nearby swales and rhine network;

• Seek opportunities for series of informal amenity areas for employees

within the landscape framework; and

• Enhance the network of local footpaths and cycle ways through creation

of a multi-use public right of way. The new route would form an essential

link between existing and proposed routes to the south and north.

17.5.48. Once the final design is agreed, the landscape proposals would cover associated

development, such as pipelines, grid connections and access roads and access

points. The landscape proposals would seek to reinstate the existing landscape

to improve nature conservation and help absorb the Proposed Development into

the levels landscape.

Landscape Management and Maintenance Plan

17.5.49. A landscape management and maintenance plan will be produced following

receipt of the DCO as a Requirement to ensure the successful establishment of

new planting. The plan would set out management and maintenance procedures

for the following key elements of the landscape scheme:

• Woodland blocks;


May 2014 Page 17-31

• Tree and shrub areas;

• Ruderal Vegetation;

• Wetland and aquatic habitats; and

• Grassland

17.5.50. Pedestrian and vehicular circulation areas would be finished in materials

appropriate to their use.

17.5.51. Lighting would be designed to minimise light pollution outside the operational

area both by appropriate selection of lighting installations to achieve minimum

lighting levels and switching arrangements to avoid unnecessary periods of

lighting. In addition, due to the proximity of the Proposed Development site to

Filton Airport, low intensity steady red aviation warning lighting and colour

markings would be positioned as close to the top of the stacks as practicable.

Summary of Mitigation

17.5.52. The soft landscape proposals, landscape management, hard landscape and

external lighting in addition to the form and materials of the buildings are a

response to the need to minimise potential adverse visual impacts and to

enhance the character of the landscape. The proposals follow mitigation advice in

EN-1 which encourages the reduction in scale of the buildings through

appropriate siting, design including colours and materials, and landscape scheme

to mitigate adverse landscape and visual impacts.

17.5.53. Planting of woodland blocks and trees and shrubs takes account of NPS-EN2

and with the aim of filtering views of the Proposed Development, visually

enclosing the DCO Site from Crook’s Marsh at a low level thereby reducing the

scale of the Proposed Development. Landscape management is proposed to

ensure the long term survival of proposed planting. External lighting design will

take account of NPPF paragraph 125 and limits the impact of artificial light

pollution on local amenity and nature conservation.

17.5.54. The predicted effects in Year 15, taking into account these mitigation measures,

are discussed below.


May 2014 Page 17-32

17.6. Residual Effects and Conclusions

Landscape Effects (Year 15)

17.6.1. The residual effects on landscape character of the Proposed Development after

15 years of operation are described in Appendix L Part 3, Volume II of this PEI

Report. The main aspects are summarised below.

Operation: Direct Landscape Effects (Year 15)

17.6.2. By Year 15 mitigation planting would have established sufficiently to enclose the

Proposed Development Site and provide structure to the Proposed Development

allowing it to integrate into the industrial landscape of the Levels. Though the

magnitude of change on the immediate landscape of the Proposed Development

Site is Medium, within the context of LCA 1 it is Low. The resulting negligible

effect is not significant.

Operation: Indirect Landscape Effects (Year 15)

17.6.3. Establishment of woodland blocks in the north and south of the Proposed

Development Site would assist in screening and softening views within and

around the Site, reducing intervisibility with adjacent LCAs. Careful design of the

form for buildings and hard landscape materials would help the Proposed

Development to be incorporated into the landscape of the existing industrial area.

17.6.4. LCA2 Severn Ridges, to the east has a High sensitivity to change and even with

established mitigation planting the Proposed Development would continue to

cause a Low magnitude of change resulting in a minor adverse indirect

landscape effect which is not considered significant.

17.6.5. LCA 5 Hallen Marsh and LCA 6 Avonmouth to the south are also expected to

continue to experience a Low magnitude of change. Though the Proposed

Development would be visible from the northern part of both LCAs, buildings and

vegetation within the LCAs and within the Proposed Development would limit

intervisibilty. The negligible landscape effects are considered not significant.

17.6.6. All other identified LCAs within the 5km study area have no intervisibility and

would experience no landscape effects, hence is of negligible significance.

Summary of Landscape Effects (Year 15)

17.6.7. The growth of the trees and shrubs planted as part of the Proposed Development

would help to absorb the Proposed Development into the landscape by year 15.

Only one LCA would experience an indirect minor effect. All other LCAs

experience negligible landscape effects, none of which are significant.


May 2014 Page 17-33

Visual Effects (Year 15)

17.6.8. The residual effects on views of the Proposed Development after 15 years of

operation are described in Appendix L Part 4, Volume II of this PEI Report. The

main aspects are summarised below.

17.6.9. The woodland blocks to the north and south of the Proposed Development Site

and planting around the balancing pond to the east would have matured

sufficiently to help reduce the scale of the Proposed Development and screen low

level plant. Habitat enhancement works to encourage ruderal vegetation,

especially along the relocated Red Rhine would have encouraged biodiversity

and protected an important habitat of the Levels.

17.6.10. Users of the PROWs on Crook’s Marsh (Receptor 10a) would experience filtered

and screened views of low level buildings and plant within the Proposed

Development. Tall structures would be visible above the woodland blocks, which

would help to reduce the scale of these structures within the views, as illustrated

in Figure 17-23 and 17-25 (Volume III of this PEI). The Medium magnitude of

change would result in a minor adverse visual effect at this location, which is not


17.6.11. Planting of woodland blocks in the northwest of the Proposed Development Site

would further filter views from the A403 (Receptors 9a and 9b) and from Severn

Beach (Receptors 11a and 11b), screening low level structures and helping to

reduce the scale of the proposed structures, as illustrated in Figures 17-28 and

17-30 (Volume III of this PEI). The resulting Low magnitude of change would

result in either a minor adverse or negligible visual effect, which is not

significant.

17.6.12. From elevated locations to the east, planting along the southern and eastern

boundary of the Proposed Development Site would help to reduce the perceived

scale of the Proposed Development and filter views of plant at low levels, as

shown in Figures 17-18 (Volume III of this PEI) and 17-20 (Volume III). The Low

visual impact would result in a negligible visual effect, which is not significant.

Summary of Visual Effects (Year 15)

17.6.13. By Year 15 of operation, the Proposed Development would cause no significant

visual effects.


17.6.14. It is envisaged that the plant would have a design life of 30 years, with an

operating life possibly beyond this. It is not possible to accurately predict the

baseline conditions at this point in the future, however it is anticipated that the


May 2014 Page 17-34

area would include the cumulative schemes outlined below, which are broadly

industrial in nature. It is also expected that decommissioning would be relatively

short in comparison to the construction period and therefore only a short-term,

temporary effect, which is likely to be similar in nature and type of effects as the

construction phase.

The decommissioning of the plant has the potential to reverse any effects

identified on the LCAs and visual amenity and would therefore have the potential

to lead to a minor, but not significant beneficial effect on these parameters.

Conclusion

17.6.15. The Proposed Development is industrial within an area surrounded by industrial

development.

17.6.16. National and District Landscape Character Assessments locate the DCO Site

within an area punctuated by large industry and recognise the landscape

character within the 5km study area is influenced by industrial works and

distributor sheds on the Levels.

17.6.17. The Proposed Development maintains the industrial character of the immediate

landscape of the DCO Site adjacent to Seabank 1 & 2 to the west, the

Severnside Energy Recovery Centre currently under construction to the

northwest, the derelict site of the former ICI / Terra Nitrogen works to the north

and the proposed large warehouses of Central Park to the northeast. The

introduction of new industrial structures into views already dominated by industry

is considered appropriate.

17.6.18. Tree and shrub planting along the southern and northern boundary would create

a new landscape framework and maintain continuity with established landscape

areas within Seabank 1 & 2 and the Western Approach Distribution Centre Phase

1. In addition, these would link to proposed landscape areas within the

Severnside Energy Recovery Centre, forming a substantial area of trees and

shrubs within the landscape.

17.6.19. All direct and indirect landscape effects identified during construction and

operation are considered not significant. The existing mixed industrial and

agricultural character of the surrounding area would be maintained and enhanced

through an appropriate industrial development. All intervisibilty of the Proposed

Development and adjacent LCAs is within the context of the existing industries.

The registered Parks and Gardens are to the south east and would experience

no intervisibility with the Proposed Development and the LCA.

17.6.20. Of the visual receptors with close range views, their views are often interrupted

by pockets of scrub and are seen within the context of adjacent industrial


May 2014 Page 17-35

development and construction sites. Away from the DCO Site, middle distance

views are experienced over the top of existing vegetation and buildings with only

the top of industrial structures visible on the skyline.

17.6.21. Distant views are usually panoramic along the Severn estuary, where the DCO

Site is seen as a small part of an expansive panorama. Clarity of these views are

dependent on weather conditions and are interrupted by structures and

vegetation in the foreground and middle ground. Often it is only the tall elements

of industrial developments which are visible in the distance with the ridgeline to

the east forming the horizon.

17.6.22. During construction there would be one significant adverse visual effect for users

of PROWs on Crook’s Marsh (Receptor 10a) with close range views of the DCO

Site. Though patches of scrub may interrupt views, the disruption resulting from

construction would result in visual intrusion. This intrusion would be seen within

the context of the industrial development on the Site and surrounds, wind

turbines and the networks of pylons carrying overhead power lines passing

through the area.

17.6.23. As the Proposed Development reaches its completed height and mass, users of

PROWs on Crook’s Marsh (Receptor 10a) would continue to experience

significant adverse effects. The woodland blocks planted along the southern

boundary would not have established by Year 1 of operation to filter views.

17.6.24. Growth of the woodland blocks and other planting after 15 Years of operation

would help to reduce the perceived scale of the Proposed Development and

screen low level plant for users of the PROWs on Crook’s Marsh (Receptor 10a)

resulting in a Minor adverse visual effect which is not considered significant. All

other visual receptors would experience neutral or not significant effects.

17.6.25. The Proposed Development would introduce a new power station into an existing

industrial area. The operation of the Proposed Development would cause limited

significant visual effects with the introduction of a new visual landmark that is

carefully designed to add interest to existing industrial views. The industrial

nature of the Proposed Development is in character with the surrounding

industrial landscape of the Levels and the Severn estuary.

17.7. Cumulative Effects Assessment

17.7.1. The Severnside and Avonmouth area is subject to a number of development

proposals, as discussed in Chapter 7: Assessment Methodology. It is important to

consider the potential for cumulative effects of the Proposed Development and

associated infrastructure with these other developments planned or consented in

the vicinity of the DCO Site. The schemes included within the cumulative effect


May 2014 Page 17-36

assessment have been identified in consultation with SGC and BCC. Existing

schemes such as Seabank 1 & 2 form part of the baseline conditions are and are

therefore not assessed here.

17.7.2. Of most relevance to the assessment of effects on landscape character and

visual amenity within a 3km radius of the DCO Site are the following:

• Avon Power Station (not consented);

• Severnside Energy Recovery Centre (currently under construction);

• Bottom Ash Facility – SITA;

• The proposed Spine Access Road (currently under construction);

• Bristol Resource Recovery Centre - SITA/Cyclamax;

• Biofuel Renewable Energy Plan on former Columbian Chemicals;

• Rockingham Park;

• Virador Resource Recovery Centre;

• Anaerobic Digestion Facility – New Earth Solutions; and

• Central Park.

17.7.3. Immediately to the northwest of the Proposed Development Site are the

proposed Severnside Energy Recovery Centre (SERC), the Spine Access Road

and the Bottom Ash Facility. Construction started on SERC in winter 2013/2014

and consists of a number of buildings including a 126m AOD stack located in the

southeast of the SERC site, close the Proposed Development Site boundary.

Balancing ponds and areas of trees and shrubs are proposed in the northwest of

the SERC site adjacent to the A403. Indicative 3D visualisations of the Proposed

Development with the SERC development are illustrated in Figure 4-6. The

grouping of buildings adjacent to the Proposed Development Site allows

development to be located together within the landscape separated by the Spine

Access Road, realigned Red Rhine and woodland blocks. Views from the A403

are filtered through the proposed landscape area along the road to the SERC

structures. The Spine Access Road will serve the Proposed Development, SERC,

and the Bottom Ash Facility and will separate these developments from Seabank

1 & 2 to the south. The grouping of development with landscape treatment

around helps to absorb the developments into the landscape and filter views from

nearby public vantage point. More distant views would see the tall elements of

the developments grouped together in a similar fashion to other developments

along the skyline in Avonmouth. Together it reduces the potential visual impact.


May 2014 Page 17-37

17.7.4. To the north of the Proposed Development Site is the proposed Avon Power

Station. This is at an early stage of planning (not consented) and is located on

the former ICI / Terra Nitrogen site, immediately north of the Proposed

Development Site. Currently there is little information regarding the design of the

scheme but the principle of grouping development and creating landscape

frameworks would help to minimise landscape and visual effects.

17.7.5. To the northeast of the Proposed Development Site is an area identified for

development of Central Park. The proposed 600 acre warehouse and distribution

park is designed to be the South West’s largest distribution park. Currently the

road infrastructure has been constructed and the area cleared for development

and undergoing land raising. Assuming the development would be similar in style

to Western Approach Distribution Park Phase 1, it would consist of large

warehouses within a landscape framework of grass verges, rhines and tree and

shrub planting along the major access routes. The development would gradually

enclose the Proposed Development Site to the north. Together the developments

would increase development within the Levels landscape but by following the

principle of grouping development and setting it within a landscape framework,

landscape features can be protected minimising landscape and visual impacts.

17.7.6. Away from the immediate boundaries of the Proposed Development Site within

the landscape to the south three developments are proposed, as discussed

below.

17.7.7. An Anaerobic Digestion Facility would be constructed to the south of the

Avonmouth LNG Storage Facility, approximately 600m southeast of the Proposed

Development Site. The development would be located away from the DCO Site

but would further industrialise Crook’s Marsh and Hallen Marsh to the south.

Users of PROWs moving through these areas would experience views of the

Anaerobic Digestion Facility with the backdrop of the LNG facility. The Proposed

Development would be in the middle distance as part of an industrial view of

Seabank 1 & 2 and the Severnside Energy Recovery Centre.

17.7.8. The Resource Recovery Centre being developed by Viridor and the Selvaco Bio-

fuel energy plant would both be located on existing industrial sites to the south of

the Proposed Development Site. These developments would be seen as part of

the industrial built up area of Avonmouth. Indicative 3D visualisations of the

Proposed Development with the Resource Recovery Centre are illustrated in

Figure 4-6, Volume III of this PEI Report.

17.7.9. Two further developments are proposed within Avonmouth, over 2km from the

Proposed Development Site. Rockingham Park, an industrial redevelopment and

Bristol Resource Recovery Centre would again be located on existing industrial


May 2014 Page 17-38

sites to the south of the DCO Site. Again, the developments would be viewed as

part of the industrial built up area of Avonmouth.

17.7.10. Cumulative developments in the vicinity of the DCO Site are all industrial and

would maintain the characteristic industrial landscape of the southern part of LCA

1 resulting in Low landscape magnitude of change and a negligible cumulative

effect by Year 15 of operation of the Proposed Development, which is not

significant. Careful grouping of built structures within a strong wooded framework,

interspersed with rhines helps to minimise both landscape and visual effects. Tall

elements of industrial developments would be seen together, providing vertical

context and minimising visual intrusion into views from identified visual receptors

resulting in Low visual impact and minor adverse to negligible cumulative visual

effects by Year 15 of operation of the Proposed Development, which are not

significant.

17.7.11. Chapter 7: Assessment Methodology explains that there is no requirement to

assess the cumulative effects of the CCS. This would form a separate DCO

Application and would be judged on its own merits, if and when it is required by

the UK Government and the technology exists. Generally speaking however, it is

considered that a future CCS development would be in line with the SGC Core

Strategy and is unlikely to cause a significant change to the landscape or visual

amenity of the area once the other cumulative schemes and the Proposed

Development have been built and implemented.




Any changes that lead to differing or new impacts and effects will be highlighted



preparation of this PEI Report and the final ES; landscape conditions are

dynamic and evolve over time. The Proposed Development Site is currently

subject to excavation, top soil stripping, and levelling in certain areas in order for

third parties to deliver the Spine Access Road and new channel for the Red

Rhine, which are discussed in Chapter 2: The DCO and EIA Process and

Chapter 7: Assessment Methodology. A haul road is also being constructed





Development.


May 2014 Page 17-39





17.8.4. Photographs used in this PEI Report were taken in early spring 2013 and will be

updated in the final ES.

17.8.5. The assessment of effects relies on field data collected during autumn 2012 and

winter 2013. Field surveys recorded existing baseline data and assessed the

likely impacts of the Proposed Development on the landscape character within a

5km radius of the DCO Site and for visual receptors within a 10km radius of the

DCO Site. This data may also need to be revisited in light of the evolving nature

of the Proposed Development Site and surrounds, due to the construction of the

SERC and Central Park in particular.

17.9. References

Ref 17-1 Landscape Institute and Institute of Environmental Management and

Assessment (2013) Guidelines for Landscape and Visual Impact

Assessment 3rd Edition

Ref 17-2 Countryside Agency and Scottish Natural Heritage (2002) Landscape

Character Assessment: Guidance for England and Scotland

Ref 17-3 Landscape Institute (2011) Landscape Institute Advice Note 01/11:

Photography and photomontage in landscape and visual impact

assessment

Ref 17-4 Planning Inspectorate (2012) Using the 'Rochdale envelope' Version

2

Ref 17-5 Natural England (2012) NCA Profile: 106 Severn and Avon Vales

(NE336)

Ref 17-6 Natural England (2013) NCA Profile: 118 Bristol, Avon Valleys and

Ridges (NE 400)

Ref 17-7 South Gloucestershire Council (2005) South Gloucestershire

Landscape Character Assessment

Ref 17-8 South Gloucestershire Council (2014) South Gloucestershire

Landscape Character Assessment – Draft Review

Seabank 3

PEI Report – Chapter 18 Sustainability and Climate Change

18. SUSTAINABILITY AND CLIMATE CHANGE

18.1 Introduction

18.1.1. This chapter of the PEI Report addresses the potential wider sustainability impacts predicted to arise as a consequence of the Proposed Development, and outlines the measures that will be considered to improve sustainability within its design and management. The Associated Development infrastructure has not been assessed within this chapter as it is considered to have an insignificant effect on climate change and has an imperceptible contribution to sustainability.

18.1.2. Through consideration of national, regional and local policy guidance promoting sustainability principles, this assessment aims to address the effects (and where appropriate propose mitigation measures) of the Proposed Development through the following key sustainability themes:

• Natural resource efficiency (land, materials, energy and water);

• Waste minimisation;

• Sustainability of the fuel stock;

• Climate change mitigation and adaptation; and

• Biodiversity and ecology.

18.1.3. It should be noted that many of the sustainability issues are also discussed elsewhere in this PEI Report. Due to overlap between subject areas and relevant chapters, these are referenced where appropriate.

18.1.4. This chapter is also supported by a Carbon Impact Assessment of the Proposed Development, contained within Appendix M, Volume II of this PEI Report. Whilst the detailed methodology is contained in this Appendix, the results are summarised in this chapter. The calculation of the carbon footprint reported in this chapter is based on the current design stage of the Proposed Development, and therefore may be subject to change going forward. Any changes will be set out and explained in the final ES, along with the final assessment conclusions.


18.1.5. Appendix D, Volume II of this PEI Report presents a summary of the planning policy relevant to this chapter.

18.2 Assessment Methodology and Significance Criteria

18.2.1. There is no standard methodology for assessing the magnitude of sustainability impacts and significance of sustainability effects of NSIPs, and each project is

May 2014 Page 18-1

Seabank 3


evaluated according to its individual characteristics. The approach taken for the Proposed Development is to qualitatively consider it against the key sustainability themes outlined above and the measures taken to incorporate and improve sustainability within the design and management are then outlined. This approach is considered to be appropriate for the likely types of impact that may result from the Proposed Development.

18.2.2. A Sustainability Assessment provides a mechanism for considering the sustainability of the project as a whole and for enhancing the benefits generated by such a project through integrating sustainability considerations throughout the lifecycle of the development. It summarises the features and attributes of the Proposed Development that will contribute to or affect each of the sustainability themes, and sets out actions which could be taken during the design, construction and operation that would further assist in delivering sustainability benefits for the local and wider area.

18.3 Baseline Conditions

18.3.1. This chapter summarises the findings of a number of other assessments within the PEI Report. Baseline information can be found in the relevant chapters referenced throughout this assessment and a description of the existing Proposed Development Site is provided in Chapter 3: The Site and Its Surroundings of this PEI Report.

18.4 Development Design and Impact Avoidance

18.4.1. The project design has taken into account a number of sustainability features, such as the selection of CCGT technology with good thermal efficiency in line with BAT, provision of sufficient water attenuation to maintain greenfield run off rates following construction of the Proposed Development, and securing a biodiversity and landscaping area. These design measures (in addition to a number of others) are discussed in more detail below.

18.5 Potential Effects and Mitigation Measures

Natural Resource Efficiency

Reducing the use of natural resources in construction materials

18.5.1. The selection of materials for the construction of the Proposed Development has been informed by sustainability principles, including the prudent and efficient use of natural resources and the use of re-used and recycled materials. A primary example of sustainable procurement is to question the need/requirement for the commodity in question.

May 2014 Page 18-2

Seabank 3


18.5.2. To minimise the use of natural resources and unnecessary materials procured for the Proposed Development, a number of services and existing infrastructure including access roads, cooling water return pipeline, gas supply pipeline and grid connection will be shared with the existing Seabank 1 & 2 generating station. Sourcing of materials will be considered once the detailed design has been confirmed.

18.5.3. A Decommissioning Plan will be produced and agreed with the EA as part of the Environmental Permitting process for the generating station. At the end of the Proposed Development’s expected operating life, all residues and operating chemicals would be cleaned out from the plant and disposed of in an appropriate manner, with the plant and all equipment removed from the Proposed Development Site.

Minimising use of Greenfield land

18.5.4. It is not intended to remove significant quantities of material from Site during construction; the land is not currently occupied by buildings and therefore no demolition is required. Topsoil removed prior to land raising would be stockpiled and retained for landscaping. The landscape proposals for the Site are to maximise the landscape ecological value through planting of native species.

Minimising use of Water

18.5.5. Water is required for a number of purposes within the generating station such as cooling, boiler feed, domestic, emergency fire water and for boiler acid washes during commissioning. The cooling process will use treated waste water from the WWTW (as currently used by Seabank 1 & 2). This cooling system is required to condense the steam used in the power generation process once it has been exhausted through the steam turbine, and before it is returned to the boiler for re-use. Hybrid-cooling technology is the method of cooling that represents BAT for the Proposed Development. In addition to re-utilising waste water, by using a bank of low height hybrid cooling cells, the volume of water being used is less than compared to direct water cooling.

18.5.6. Other water efficiency measures will be adopted where possible to reduce the effect on the water supply network. These include:

• Selection and specification of water efficient equipment to reduce the amount of water required;

• Implementation of staff-based initiatives such as turning off taps, plant and equipment when not in use both on-site and within site offices; and

May 2014 Page 18-3

Seabank 3


• Use of recycling water systems such as wheel washes, site toilets, hand washing.

18.5.7. Water consumption will be monitored through process and administration areas to identify opportunities for water usage reduction and leak detection.

Maximising Energy Efficiency

18.5.8. The design of the Proposed Development is based on the principles of BAT as outlined in the European Reference document on Best Available Techniques for Large Combustion Plants (“Best Available Technique reference ‘BREF Notes’”). The CCGT will operate at an anticipated efficiency of around 58% which compares favourably with indicative BAT efficiencies for equivalent power generation from natural gas (54-58% for new plants, 50-54% for existing plants) and is considerably higher than that for conventional coal, oil or gas fired steam turbine generating plants.

18.5.9. The peaking plant will either be OCGT or reciprocating engine technology. OCGT units are slightly less efficient than reciprocating engines (41% efficient for OCGTs, compared to 45% for a reciprocating engine) and so OCGTs have been used in modelling the carbon emissions from the Proposed Development as a ‘worst-case’ scenario from a climate change impact assessment perspective.

18.5.10. The peaking plant avoids having to operate the CCGTs at low loads to cover short-term peaks in electricity demand, which would be less efficient than purpose built peaking plant.

18.5.11. The modern plant design follows current best practices in optimising efficiency and the use of CCGT technology is recognised as indicative BAT for power generation from natural gas (with reference to the BREF Note) by capturing heat remaining in the gas turbine exhaust, and creating steam to generate additional electricity via a steam turbine.

18.5.12. There are numerous design elements which will contribute to achieving this efficiency including:

• Automated process control to optimise combustion conditions and performance;

• Plant components will be sized appropriately for the design capacity of the plant;

• Where possible, variable speed drives will be included on all sizeable motors (such as cooling water pumps and fans); and

• Insulation of heated surfaces and minimisation of pipe runs.

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Seabank 3


18.5.13. Regular planned maintenance will also be conducted to optimise the efficiency of the equipment.

18.5.14. The Applicant is focused on generating electricity as efficiently as possible and maximising exported power. Therefore several Key Performance Indicators (KPIs) regarding energy efficiency will be monitored regularly and tracked during plant operation, including the MWe exported per kWh of natural gas consumed and the parasitic load (i.e. the difference between gross and net power output), with a small increase in the parasitic load triggering the need for further evaluation .

18.5.15. The Applicant is strongly committed to providing energy in a reliable and sustainable way and a key priority is a significant and continuing reduction in the carbon intensity of the electricity produced by its generation fleet. This is defined in the Applicant’s corporate goal to reduce the carbon intensity of electricity generated by 50% by 2020 (against a 2006 baseline). This goal will be achieved through a diverse range of solutions including:

• The commissioning and development of additional renewable energy capacity within the company portfolio;

• Lower emissions from more efficient and flexible gas-fired generation;

• Delivering innovative solid fuel solutions at coal-fired stations; and

• Reduced output from coal-fired stations as they use up their allocated running hours under the EU’s Industrial Emissions Directive.

18.5.16. The Applicant has also successfully completed the Certified Emissions Management and Reduction Scheme (CEMARS) and encouraged eighty six of its main suppliers to sign up to the programme (Ref. 17-2).

Waste Minimisation

18.5.17. The Applicant endorses the waste hierarchy, where the first priority is to prevent waste, second priority is to reuse and the last resort being disposal.

18.5.18. The CEMP will be produced prior to construction of the Proposed Development and will set out how waste will be managed on site, and opportunities to recycle waste will be explored. A framework for the CEMP is presented in Appendix C, Volume II of this PEI Report. Additionally a Decommissioning Plan will be produced as outlined above, with all residues and operating chemicals cleaned out from the plant and disposed of in an appropriate manner at the end of the Plant’s operating life.

18.5.19. Some waste will be generated during the construction programme including packaging and liquid wastes such as oils and chemicals. During the construction

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phase, waste management requirements will be communicated to all contractors and sub-contractors to ensure waste is managed in accordance with the waste hierarchy and relevant statutory controls. These measures will be controlled through the CEMP.

18.5.20. There is not expected to be significant waste associated with the operational phase of the Proposed Development. Those that are generated will be managed and treated in line with the waste hierarchy and recycled where possible, or otherwise disposed of through an appropriately licensed waste contractor.

Sustainability of the Fuel Stock

18.5.21. Natural gas will be used as the primary fuel source for the turbines, supplied from the National Grid Transmission network. Two high pressure natural gas feeds supply the current Seabank 1 & 2 generation station and these will be used to supply the gas to the Generation Station Site.

18.5.22. National Grid has undertaken a feasibility assessment and does not expect that significant infrastructure upgrades will be required to deliver the necessary gas to the Proposed Development.

Climate Change

18.5.23. The design, construction and operation of the Proposed Development will seek to mitigate the causes of climate change by contributing to reducing greenhouse gas emissions from UK electricity generation and adapting to the predicted impacts of climate change, as discussed below.

Mitigation: Carbon Footprint Assessment 18.5.24. A preliminary carbon impact assessment has been undertaken for the Proposed

Development using the Greenhouse Gas Protocol (Ref: 16-3) as a basis. The Protocol provides a methodology for calculating the carbon footprint of a project and was developed by the World Resources Institute and the World Business Council for Sustainable Development.

18.5.25. Where possible, design values for the Proposed Development have been used, however some assumptions have been made where data is not yet available or where exact values are not known; these assumptions are detailed in Appendix M, Volume II of this PEI Report. Any changes to these assumptions between preparation of this report and submission of the DCO application will be highlighted in the final ES and the assumptions on which the final assessment is based will be clearly stated. It is not currently anticipated that any such changes would substantially change the outcome of this preliminary assessment.

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18.5.26. The Greenhouse Gas Protocol defines different sources of GHG emissions into a series of categories or ‘scopes’. These definitions have been used in this assessment to determine the scope and sources of emissions to be considered and the relevant aspects to the Proposed Development are as follows:

• Scope 1: Direct Emissions

o Fossil Fuel combustion on site: Natural Gas and Distillate (for black starts only);

• Scope 2: Electricity Indirect Emissions

o Not applicable. The parasitic load of the plant will be sourced from the electricity generated on site therefore there are not expected to be any Scope 2 emissions;

• Scope 3: Other Indirect Emissions

o Transport of raw materials to site;

o Transport of waste materials from the site;

o Transport of distillate to site has been scoped out, as it will only be required for a black start event which is considered to be abnormal and not required in significant volumes.

18.5.27. Table 17-1 below summarises the total annual operational carbon footprint of the Proposed Development, based on the preliminary assessment. This is calculated at 1,161,353 tonnes CO2 equivalent (tCO2e) based on current assumptions.

Table 17-1: Total Footprint Emissions Element of Footprint tonnes CO2e Scope

Natural Gas combustion 1,161,301 Scope 1 Electricity consumption N/a Scope 2 Natural Gas Transport N/a Scope 3 Raw materials transport 49 Scope 3 Waste transport 2 Scope 3

TOTAL annual carbon emissions 1,161,353

18.5.28. Considering Scope 1 emissions only, and based on currently available information, the carbon intensity of the Proposed Development is approximately 331tCO2/GWh during operation and assuming full load. This compares favourably to the carbon intensity of both the average UK power station (using all fuel types including nuclear and renewable) and an average UK natural gas fired power station, which have carbon intensities of 483tCO2/GWh and 415tCO2/GWh

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respectively (Ref. 17-4). Therefore the Proposed Development represents annual carbon savings of between 84 and 152 tonnes of CO2 on a per GWh basis compared to UK average power stations for the generation of electricity alone. Bearing in mind that the Proposed Development is replacing coal fired power station that are being shut down under the requirements of the Large Combustion Plant Directive, which are more carbon intensify than the UK average power station, this calculated figure is considered robust and possibly an underestimate of the annual carbon savings.

18.5.29. Note these indicative carbon savings include the emissions associated with the Scope 1 emissions only, but the additional of Scope 3 emissions will make a negligible difference to these calculations. As indicated in Table 17-1 above, the majority of emissions will originate from the combustion of the fuel. This remains the case even when sensitivity tests were carried out to double the distance the raw materials and waste were hypothetically transported (from 80km to 160km), with an increase of less than 0.1% to the overall footprint.

18.5.30. It is recognised that technological progress and developments in the regulatory framework for the use of carbon capture technology are likely to occur within the lifetime of the Proposed Development. Therefore, in accordance with UK CCR requirements, the Proposed Development will incorporate an area set aside for the potential future installation of Carbon Capture technology, and the design of the new power station will be developed with consideration for the possible future retrofitting of carbon capture technology at some future date. A CCR report will be submitted in support of the DCO application. Should carbon capture be installed in the future, approximately 90% of the carbon emissions from the Proposed Development would be compressed and captured.

Transport

18.5.31. A detailed Transport Assessment is considered in Chapter 10: Traffic and Transport. Transport during the operational phase has been excluded from the scope of that assessment as agreed with SGC, BCC and the HA, given the difference in traffic volumes associated with each phase.

18.5.32. A Travel Plan will be prepared for the construction phase of the Proposed Development. The implementation of measures within the prepared travel plan will seek to reduce the number of vehicles travelling to and from the site during construction. Measures within the Travel Plan will include encouraging journeys by public transport through the provision of shuttle bus services at public transport interchanges, introduction of a car sharing scheme to reduce single occupancy car journeys and other measures to promote cycling and walking.

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18.5.33. Opportunities to transport materials for the enabling works by rail and via the Avonmouth Port will be explored and discussed with the appropriate authorities and chosen contractor, although at this stage of the project it has been conservatively assumed all trips would be via road. Additionally, the impact on the highway network will be reduced through implementing measures such as limiting the number of deliveries during peak hours and stockpiling material to avoid deliveries during holiday periods. Distances travelled will be reduced where feasible through for example the use of material sourced from local quarries and of construction materials sourced from local suppliers in the Avonmouth/ Severnside area.

18.5.34. There will be no vehicle movements associated with the delivery of primary fuel (natural gas) to the Proposed Development as this will be supplied directly from the National Grid Transmission Network. Traffic movements during the operational phase will be restricted to staff travel, delivery of auxiliary materials and back-up distillate fuel and transport of waste from the Site.

18.5.35. The preliminary carbon assessment of the Proposed Development (Technical Appendix M, Volume II) encompasses carbon emissions arising from the transport of auxiliary raw materials to the Site as well as waste arising from the Proposed Development. It demonstrates the relatively small contribution of carbon emissions associated with the transport within the overall annual carbon footprint, even when a worst-case scenario is considered and the distances travelled are hypothetically doubled.

Climate Change Adaptation

18.5.36. In addition to any potential impacts the Proposed Development may have on climate change, there is the potential for climate change to impact on the design and operation of the Proposed Development. Such climatic impacts may include increased incidences of heavy and prolonged rainfall which could increase flood risk from surface water, groundwater and drainage systems. As such, adaptation to climate change concerns how the Proposed Development avoids or reduces its exposure to the effects of future climate change such as increased temperatures and flood risk.

18.5.37. The management of risk from climate related events has been considered by the Applicant for a considerable period of time. The Applicant has prepared a Climate Adaptation Report (June 2011) (Ref. 17-5) and has prepared for such eventualities within its Asset Management System, for example through enhancing its ability to respond to the extreme weather events more likely with climate change.

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18.5.38. A full FRA will be provided with the DCO Application and the findings included in the final ES. Chapter 14: Flood Risk, Hydrology and Water Resources summarises the FRA which is provided in Appendix J, Volume II of this PEI Report.

18.5.39. The outputs of the UK Climate Projections (UKCP09) climate change scenarios indicate a shift towards wetter winters over the whole of England by as much as 20% by the 2050s. The UKCP09 climate projections have been included in the Flood Risk Assessment.

18.5.40. Without action, there would be potentially high risk of flooding on the Proposed Development Site from fluvial and tidal sources. To mitigate this risk, the FRA proposes raising the finished floor levels of the Generating Station Site to up to 8.31m AOD in order to protect against extreme flooding and taking into account climate change allowance; the DCO Application includes additional contingency and allows the finished ground levels to be raised up to 8.5m AOD. The FRA indicates that during the ‘future baseline’ scenario, land raised within the Generation Station Site boundary will not be flooded for all fluvial scenarios, including 1 in 1000 years (inclusive of climate change) events and all tidal scenarios (including breach events) up to 1 in 200 years (inclusive of climate change) events. On completion of the Proposed Development, surface water runoff will be restricted to pre-development rates using Sustainable Urban Drainage System (SuDS) techniques. The FRA includes a commitment to include a surface water pond(s) up to 3,800m3 capacity based on the maximum built area for the Proposed Development.

18.5.41. As discussed previously the Proposed Development also incorporates a number of measures to conserve water during operation. This will increase the Proposed Development’s resilience to future temperature rises and potential droughts as a result of climate change.

Biodiversity / Ecology

18.5.42. Chapter 16: Ecology of this PEI Report considers in detail the potential effects and associated ecological effects of the Proposed Development on landscape and wildlife. Surveys have shown that the current site represents a mix of habitats currently, mainly grassland, shrub and watercourses / wetland.

18.5.43. Potential adverse ecological impacts resulting from the construction and operation of the Proposed Development could result from the loss of habitats, direct and indirect disturbance to species, changes to surface water drainage, potential pollution events during construction, lighting effects and air quality changes. Effective mitigation measures have been incorporated into the design of the Proposed Development to address these likely impacts. These are

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summarised in Chapter 16 Ecology and include the creation of areas of habitat suitable for reptiles; maintaining strips of rough, tussocky grassland alongside hedgerows and rhines; and the incorporation of green roofs and brown roofs on some of the lower structures to provide suitable habitat for terrestrial invertebrates.

18.6 Residual Effects

18.6.1. Several characteristics are incorporated into the design, construction and management of the Proposed Development which meet the key sustainability requirements of sustainable design and efficient, sustainable use of land, material and resources, as set out in national, regional and local policy.

18.6.2. Through the design, construction and operation of the Proposed Development, the Applicant seeks to mitigate the causes of climate change by contributing to reducing greenhouse gas emissions associated with UK electricity generation and adapting to the predicted impacts of climate change. It will provide a lower carbon source of electricity than the UK average, with the carbon assessment demonstrating that the Proposed Development will outperform the UK average fleet of existing power stations within the UK on a tonnes CO2 per GWh basis.

18.6.3. The Proposed Development will incorporate a number of design and operational measures to increase resilience to potential effects of climate change including the mitigation of potential flood risk.

18.7 Cumulative Effects Assessment

18.7.1. This section assesses the effect of the Proposed Development in combination with other developments in the area that have been identified in Chapter 7: Assessment Methodology (section 7.4).

18.7.2. It is not considered that the other developments in the area have the potential to lead to cumulative sustainability effects when considered with the Proposed Development.


18.8.1. The calculation of the carbon footprint reported in this assessment is based in the current design stage of the Proposed Development, and therefore may be subject to change as further design work is undertaken. Any changes will be set out and explained in the final ES, along with the final assessment conclusions.

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18.9. References

Ref. 17-1 Biodiversity 2020: a Strategy for England’s Wildlife and Ecosystem Services (Defra) August 2011

Ref. 17-2 SSE plc Annual Report 2013

Ref. 17-3 GHG Protocol for Project Accounting’ World Resources Institute and the World Business Council for Sustainable Development (2005).

Ref. 17-4 Electricity: chapter 5, Digest of United Kingdom energy statistics (DUKES). Published by the Department of Energy & Climate Change (DECC), July 2013. Available online: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65818/DUKES_2013_Chapter_5.pdf (last accessed 12th November 2013)

Ref. 17-5 SSE Power Distribution. Climate Change Adaptation Report. Appended Version 3.1, June 2011. Available online: http://archive.defra.gov.uk/environment/climate/documents/adapt-reports/04distribute-trans/sse-power-distribution.pdf

May 2014 Page 18-12

Seabank 3 PEI Report – Chapter 19 Health

May 2014 Page 19-1

19. Health

19.1. Introduction

19.1.1. This chapter identifies the potential health and wellbeing effects (both adverse

and beneficial) of the Proposed Development.

19.1.2. The information has been consolidated, following a request from the Health

Protection Agency (HPA), into a single chapter for the purposes of ensuring

health related information is in a readily accessible place for interested parties.

19.1.3. The assessment draws on the findings of other technical assessments, as set out

in various chapters of this this PEI Report, namely Chapter 9: Socio-economics;

Chapter 10: Traffic and Transport; Chapter 11: Air Quality, Chapter 12: Noise and

Vibration; and Chapter 13: Ground Conditions.

19.1.4. Where potential for specific health and wellbeing impacts are identified in a

technical assessment, this chapter will set out the significance of effect on the

receptors identified and any specific health mitigation required.

Consultation


to allow stakeholders the opportunity to comment on ES.

19.1.6. A summary of the scoping request responses that relate to health are presented

in Table 19-1.



Health Protection Agency (HPA) – Public Health England

Health impacts should be consolidated into a separate chapter of the ES or carried out as a separate HIA.

This chapter is provided in direct response to this request. A summary of impacts related to health are presented in Table 19-2.

The health chapter or HIA should consider potential health impacts associated with the electric and magnetic fields around substations and the connecting cables or lines.

The potential impacts of electric and magnetic fields are addressed in section 19.3

The EIA should give consideration of the COMAH Regulations (Control of Major Accident Hazards) and the Major Accident Off-site Emergency Plan (Management of Waste from Executive Industries) (England and Wales) Regulations 2009.

Consideration is given to the COMAH Regulations in Chapter 13: Ground Conditions. Seabank 1 & 2 already Emergency Plan in place. The Proposed Development will be incorporated into this plan as described in Chapter 4: Project Description.


May 2014 Page 19-2

Overview of the Proposed Development Site

19.1.7. The Proposed Development Site is located in an area of approximately 19ha

situated immediately east of the existing Seabank 1 & 2 station and wholly

located within the administrative boundary of SGC. The Site is within a

predominantly industrial area north of Avonmouth and constitutes a relatively flat

area of open, uneven grassland. The nearest receptors to the Site boundary are

the local industrial properties to the north and southwest, and the agricultural land

to the east. A detailed site description can be found in Chapter 3: The Site and Its

Surrounds. A description of the development is provided in Chapter 4: Project

Description.


19.2.1. There is no single guidance associated with the scope and method of HIA for the

assessment of development projects nor is there a mandatory methodology for

assessing NSIPs. There is however a series of guidance documents prepared for

a variety of land use or public health situations. In undertaking this assessment

we have reviewed the following guidance:

• Healthy Urban Development Unit: Rapid Health Impact Tool (Ref. 19-1);

• Merseyside Guidelines for Health Impact Assessment (Ref. 19-2).

19.2.2. This assessment is based on the residual effects identified in the PEI Technical

Chapters 9-13. These effects are analysed against the baseline conditions set

out in the community profile to determine if there is likely to be a direct or indirect

health effect:

• Direct influences – e.g. atmospheric pollutant deposition, severance,

delays, noise, land contamination;

• Indirect influences – e.g. road safety, access to work and employment.

19.2.3. This assessment has considered the likely health effects in a qualitative manner

as it is not practical to quantify the nature of these effects against a standardised

methodology or criteria. However the assessment of each health effect is

described using the scale presented in Table 19-2.


May 2014 Page 19-3

Table 19-2: Scale of Health Effects

Effect category Description

Beneficial A perceived or predicted improvement to health of workers, local residents and members of the community, or recreational users, which can be categorised as major, moderate or minor if sufficient information is available.

Negligible No discernible health effect

Adverse A perceived or predicted deterioration to health of workers, local residents and members of the community, or recreational users, which can be categorised as major, moderate or minor if sufficient information is available.

19.2.4. At present, it is anticipated that the main potential effects to human health arising

from the Proposed Development will result from changes to local air quality and

traffic and transport, during the construction, operation and demolition stages of

the Proposed Development. However, as with any project of this magnitude,

there are also potential effects arising from contaminated land, road safety and

noise impacts.

19.2.5. The assumptions that underpin this assessment are:

• The methodology for each assessment and significance criteria is

provided in each of the technical chapters stated within this PEI Report;

• All mitigation measures listed in the technical chapters are assumed to be

implemented;

• Baseline health data is based on 2009-2011 Public Health England data

sources.

Receptors

19.2.6. Health receptors include members of the public working or living in the vicinity of

the Site (including workers), that can potentially be affected by a source such as

ground contamination, air quality or noise. As shown in Plate 19-1 receptors only

become exposed to contamination via a pathway. Receptor sensitivity can vary in

relation to health, age and duration of exposure and different receptors are likely

to be affected by different stages and activities of the project e.g. construction

and operation.


May 2014 Page 19-4

Plate 19-1: Source Pathway

19.2.7. The nearest residential communities to the Proposed Development Site are

located approximately 1.5km north of the Proposed Development Site in Severn

Beach, together with a small number of farms located approximately 1.1km

southeast.

19.2.8. The larger communities of Avonmouth and Bristol are located some 5km

southwest and 10km south east of the Proposed Development Site respectively.

19.2.9. The nearest residential properties to the proposed cooling water pipeline corridor

are situated approximately 800m east of its most southern point (near the

WWTW). There are no residential properties closer than 800m between the

WWTW and Seabank 1 & 2, as shown in Figure 3-5 in Volume III of this PEI

Report.

19.2.10. Chapter 11: Air Quality states that construction dust emissions and construction

plant exhaust emissions are unlikely to affect health receptors beyond 300m of

the construction site boundary. Road traffic emissions are also unlikely to be an

issue beyond 200m from the road source. The potential for air emissions to affect

health is therefore considered to be limited to the operational emissions

associated with the CCGTs and peaking plant.

19.2.11. Health receptors for each area of impact are described in more detail within

Chapters 9-18 and depicted in the constraints plan in Figure 3-5, Volume III of

this PEI Report.


19.3.1. This section considers the existing community profile in the study area, taken to

be the Bristol and South Gloucestershire region. This includes the current health

status of the population.

19.3.2. Health profiles for each local authority area are produced annually by Public

Health England (PHE) and these provide a summary of the health of people

within defined areas and a comparison of local health with average values for all

areas of England. Health profiles have been obtained from PHE for Bristol and

South Gloucestershire (Ref. 19-3).


May 2014 Page 19-5

19.3.3. Further data on Bristol and South Gloucestershire has been obtained through the

Joint Strategic Needs Assessment (JSNA). JSNAs have been produced by both

South Gloucestershire (Ref. 19-4) and Bristol City Council (Ref. 19-5).

19.3.4. The health of people living in South Gloucestershire is generally better than the

average of England as a whole while the health of people living in Bristol is varied

when comparing life expectancy, deprivation, infant mortality and causes of

premature mortality such as smoking and obesity (Ref. 19-3).

19.3.1. A summary of the data obtained from the 2013 PHE Health Profiles for the

individual local authorities is provided in Table 19-2. The red text indicates a

higher than average value in England, whilst the green text indicates a lower than

average value.

Table 19-3: Health indicator data for England, South Gloucestershire and Bristol

Health indicator England Average

South Gloucestershire

Bristol

1. Deprivation 20.3% 0.5% 25.8%

2. Long term unemployment 9.5 4.3 11.0

3. Life expectancy male 78.9 80.7 78.0

4. Life expectancy female 82.9 84.6 82.6

5. Infant death 4.3 2.3 2.7

6. Adults smoking 20.0% 16.5% 21.0%

7. Obese adults 24.2% 26.2% 22.7%

8. Obese children Year 6 19.2% 15.3% 19.1%

9. Smoking related deaths 201 159 219

10. Early deaths – heart disease and stroke

60.9 41.9 63.3

11. Early deaths- cancer 108.1 95.7 120.7

12. Road injuries and deaths 31.5 23.2 41.9

1 % people in this area living in 20% most deprived areas in England, 2010; 2 Crude rate per 1,000 population aged 16-64, 2012; 3 At birth, 2009-2011; 4 At birth, 2009-2011;5 Rate per 1,000 live births, 2009-2011; 6 % adults aged 18 and over, 2011/12; 7 % adults, modelled estimate using Health Survey for England 2006-2008; 8 % school children in Year 6 (age 10-11), 2011/12; 9 Directly age standardised rate per 100,000 population aged 35 and over, 2009-2011; 10 Directly age standardised rate per 100,000 population aged under 75, 2009-2011; 11 Directly age standardised rate per 100,000 population aged under 75, 2009-2011; 12 Rate per 100,000 population, 2009-2011


May 2014 Page 19-6

Life Expectancy

19.3.2. Life expectancy is a good indicator for the overall health of a population. Based

on the most recent 2009-2011 data, life expectancy at birth for both men and

women is higher than the England average in South Gloucestershire. In Bristol

the life expectancy for men is 0.9 years lower than the England average, while for

women it is 0.3 lower than the England average.

19.3.3. Both the male and female average life expectancy values for South

Gloucestershire and Bristol are shown in Table 19-4.

Table 19-4: Life Expectancy from Birth (Ref. 19-3)

Location Female Average (years) Male Average (years)

England 82.9 78.9

Bristol 82.6 78.0

South Gloucestershire 84.6 80.7

Health Inequalities and Deprivation

19.3.4. The Marmot Review recognises health inequalities are a directly linked to

differences in population health (Ref. 19-6).

19.3.5. In general, health inequalities in Bristol and South Gloucestershire mirror those

nationally and they are well documented between individual areas within each

local authority.

19.3.6. Seven components are factored into the Index of Multiple Deprivation (IMD)

score: values for income; employment, health deprivation and disability;

education skills and training; housing; geographical access to services; and living

environment. In South Gloucestershire, multiple deprivation is lower than average

(0.5), while in Bristol multiple deprivation is higher (25.8) than the England

average (20.3).

19.3.7. The estimated level of adult obesity in South Gloucestershire is worse than the

England average, while in Bristol the level is better than the England average. In

relation to children, in Year 6, 15.3% of children are classified as obese in South

Gloucestershire compared to 19.1% in Bristol, both lower than the England

average of 19.2%.

19.3.8. In South Gloucestershire, life expectancy between the least deprived and most

deprived differs by 6.2 years for men and 4.8 years for women. In comparison,

life expectancy in Bristol is 9.4 years lower for men and 5.8 years lower for

women in the most deprived areas of Bristol than in the least deprived areas.


May 2014 Page 19-7

19.3.9. Long term unemployment is another indication of deprivation and is a key

determinant of health. In South Gloucestershire long term unemployment was

lower than the England average while in Bristol long term unemployment was

higher than the England average.

Premature Mortality

19.3.10. In both South Gloucestershire and Bristol over the last 10 years, all causes of

mortality have fallen. This includes, on average, reduced early death rates from

cancer and from heart disease and stroke.

19.3.11. Smoking related deaths continue to be a major cause of premature mortality and

in Bristol the rates are worse than the England average while in South

Gloucestershire the rates are better than the England average.

19.3.12. The rate of road injuries and deaths in South Gloucestershire and Bristol is better

than the England average.

19.3.13. The premature mortality rate (defined as deaths from all causes under 75 years)

is also an important indicator of the overall health of the population. The

premature mortality rate in South Gloucestershire is lower than the England. In

Bristol the premature mortality rate has fallen gradually over recent years, but

remains steadily higher than the England average.

19.3.14. Cancer and cardiovascular disease remain the two main causes of death in

South Gloucestershire and Bristol. In South Gloucestershire rates are below the

national average while in Bristol rates are worse than the England average.

19.3.15. The most common forms of respiratory disease include chronic obstructive

pulmonary disease (COPD) and emphysema (both strongly related to tobacco

smoking), asthma (related to allergy, exercise and lung infection) and a variety of

infections of lung tissue. Although COPD death rates in men are slowly

decreasing, rates in women are increasing in South Gloucestershire. This is a

similar pattern to death rates from lung cancer and it reflects long term trends in

smoking (Ref. 19-3). The prevalence of COPD in Bristol is higher than the

England average.

Future Baseline

19.3.16. The future baseline conditions are not anticipated to be significantly different to

the existing baseline conditions. As described in Chapter 11: Air Quality the

assessment predicts a slight improvement in ambient pollutant concentrations.

Mean annual NO2 is likely to be the key pollutant of concern to human health and

is predicted to reduce from a background concentration of 23.0µg/m3 to

18.1µg/m3 between the present-day and 2019 without the Proposed


May 2014 Page 19-8

Development (this is the earliest date the Proposed Development could

theoretically be commissioned). This is a result of more rigorous environmental

legislation and improved vehicle emissions in the UK and represents

approximately 45% of the National Air Quality Strategy objective for mean annual

NO2 (of 40µg/m3) in 2021.


19.4.1. A number of impact avoidance measures have been incorporated into the project

design that is relevant to health effects.

19.4.2. Chapter 9: Socio-economics notes that the Proposed Development incorporates

a new PROW to provide cyclist and footpath access from Ableton Lane to the

existing roundabout that is situated immediately east of the Proposed

Development Site. This new PROW will also incorporate a bridleway for horse

riders.

19.4.3. There are no specific health impact avoidance measures that have been

implemented in the design of the Proposed Development relevant to traffic and

transport, however a number of avoidance measures have been included that are

relevant to air quality, as discussed in Chapter 11: Air Quality. In particular:

• The Proposed Development has been designed such that process

emissions to air will comply with the emission limit values specified in the

Industrial Emissions Directive. This will be enforced by the EA through the

Environmental Permit required for the operation of the generating station;

• The stack heights have been optimised with consideration given to

minimisation of ground level air quality impacts, against the visual impacts

of taller stacks. Preliminary dispersion modelling was undertaken to

determine the optimum stack height range and local residents informally

consulted regarding their preference;

• The proposed locations of the peaking plant and its stacks was modified

during the design evolution, as outlined in Chapter 6: Project Need and

Alternatives, when preliminary dispersion modelling demonstrated that a

lower stack height and lower offsite effects could be achieved by moving

this plant further from the HRSG buildings.

19.4.4. The design of the Proposed Development has also been carried out in

conjunction with the acoustics consultants to identify locations and building

orientations that would minimise the noise impact at nearby noise sensitive

receptors, as discussed in Chapter 12: Noise and Vibration. Noise mitigation

measures that were analysed during the preparation of the concept layout

included building cladding. The chosen layout considers the findings of the noise


May 2014 Page 19-9

assessment, along with other appraisals of potential environmental impacts and

constructability and maintainability factors to achieve an optimal layout.

19.4.5. Chapter 13: Ground Conditions notes that the Proposed Development

incorporates a minimum 8m buffer strip alongside the southern side of the

realigned Red Rhine for access by the LSIDB. This should inherently reduce

pollution risks of this watercourse during construction and thereafter , by creating

a natural setback from this watercourse.


19.5.1. It is anticipated that effects on health have the potential to arise from the

following sources:

• Construction phase – atmospheric pollutant deposition, traffic, noise, land

contamination;

• Operation Phase – plant emissions, construction dust atmospheric

pollutant deposition, traffic, noise; and

• Decommissioning Phase – as for construction phase.

19.5.2. Each of these potential effects has been considered and reported on in the

preliminary technical assessments within this PEI Report and a summary is

provided below.

Construction Phase Disturbance and Nuisance

Traffic and Transport

19.5.3. As reported in Chapter 10: Traffic and Transport a maximum increase of 6-7% is

predicted at the junction A403 / Severn Road / Chittening Road during the

enabling works and approximately 12% increase during the peak month of the

construction phase. This level of change during the peak month of traffic

generation is considered to be negligible. The effect during other months and

activities is expected to be less, and therefore also negligible. Based on the

conclusions in Chapter 10: Traffic and Transport, and the minimal increase in

traffic from the construction, there is not predicted to be an effect on delays in

vehicles at the junction and therefore the effect on public health is considered to

be negligible.

19.5.4. The A403 is the main pedestrian and cycling route in the study area assessed in

Chapter 10: Traffic and Transport. The predicted increase in total vehicles is

expected to be approximately four vehicles during peak hours along this route

during the enabling phase, prior to any mitigation for HGVs. During the peak

month of the construction phase, a total increase of 53 and 43 vehicles (including


May 2014 Page 19-10

HGVs) is expected during the morning (0800-0900) and evening (1700-1800)

peak hours. Given the current level of pedestrian and cyclist activity along the

study roads, it is considered unlikely that temporary increases in traffic during

enabling works and the construction phase would result in difficulties for

pedestrians and cyclists to cross the A403. Chapter 10: Traffic and Transport

concludes the effect of severance during all phases of the Proposed

Development is negligible. Based on this conclusion the effect on public health

is considered to be negligible.

19.5.5. The risks of vehicular accidents associated with the Proposed Development is

likely to be localised to the construction site given that construction is temporary,

the changes predicted are temporary, and the estimated hourly traffic generation

is low relative to the total flows on the roads. With successful adoption of the

mitigation measures outlined within Chapter 10: Traffic and Transport it is

therefore considered unlikely that there would be an effect upon road safety and

accident levels due to Proposed Development traffic. Chapter 10: Traffic and

Transport concludes the risk of accidents is negligible and therefore the effect

on public health is therefore deemed to be negligible.

Air Quality

19.5.6. The predicted residual effect of dust emissions and deposition during enabling

works and construction of the Proposed Development is anticipated to be minor

adverse on sensitive receptors. Dust deposition does not directly lead to any

health effects however (once deposited it is not inhaled unless it is entrained in

the air again) and it would be temporary in nature, lasting only for the duration of

works onsite. Airborne particulate matter should only be a concern within the

immediate proximity to the construction works (e.g. 30-50m) and is therefore not

a concern to local residential dwellings (which are 1.1km from the Proposed

Development Site).

19.5.7. The residual effect of airborne particulate matter and atmospheric emissions

associated with construction plant and road traffic exhaust emissions is predicted

to be negligible, largely due to the large distance between the Site and any

sensitive receptors which allows significant dispersion of emissions.

Noise and Vibration

19.5.8. The predicted construction noise levels were assessed against the daytime and

night-time Threshold Values derived from the BS 5228 ABC method for

assessing the noise effects from construction activities. Predictions have shown

that noise levels from standard construction activities will fall below the Threshold

Values at the selected residential receptors during all construction activities


May 2014 Page 19-11

during both daytime and night-time periods. A negligible significance of effect

has therefore been predicted.

19.5.9. Noise levels from construction traffic during the construction phase are not

expected to result in a perceptible change in noise according to the noise criteria.

A negligible significance of effect has therefore been predicted for road traffic.

19.5.10. Chapter 12: Noise and Vibration provides a number of mitigation measures and

states the contractor will employ Best Practicable Means in order to ensure that

construction noise is kept to a minimum.

19.5.11. Based on this conclusion the effect on public health arising from noise is


Ground Contamination

19.5.12. Potential sources of contamination have been identified within Chapter 13:

Ground Conditions. The Proposed Development is proposed to be constructed

on previously undeveloped land, however the surrounding land uses could have

affected the Proposed Development Site soil and groundwater quality. The

surrounding land uses are predominantly industrial and agricultural.

19.5.13. Construction workers are the main receptor during the construction phase in

relation to contamination; it is not expected that people offsite would be affected.

Industry standard mitigation measures are outlined within Chapter 13: Ground

Conditions and include provisions for detailed site investigation, risk assessment

and remediation design and implementation for example.

19.5.14. Contamination within soils has the potential to adversely affect the health of

construction workers without appropriate duty and care. Health and safety

measures will be implemented to protect the construction workers’ health; for

example the appropriate use of PPE, hygiene practices and decontamination

units, if required.

19.5.15. Prior to the commencement of excavation works appropriate steps including a

detailed survey of the services locations and depths will be taken to ensure that

construction activities do not disturb any live services and reduce the risk of

disturbing existing utilities to negligible significance.

19.5.16. Encountering unexploded ordnance (UXO) onsite during piling and excavation

represents a potential major effect to the safety of construction workers. A UXO

study has already been undertaken for the Proposed Development Site. A further

UXO desk study report will be commissioned prior to construction, to fully assess

the risk of encountering UXO on site and recommend any mitigation measures

required to render potentially adverse effects negligible. Such mitigation


May 2014 Page 19-12

measures may include the presence of an Explosive Ordnance Disposal

Engineer on site to supervise open excavations and down-hole intrusive

magnetometer surveys of all deep intrusive works and target investigation of

suspect anomalies. Following this mitigation, such as the removal of identified

UXO, where required, and taking into account the low risk of occurrence, the

significance of this effect is considered to be negligible.

19.5.17. After implementation of the mitigation measures, the effect on the public health of

construction workers is expected to be negligible.

Socio-economics and Employment

19.5.1. As described in the Marmot Review employment is a key determinant of health

(Ref. 19-6). The relationship between socio-economic position and educational

outcome has significant implications for subsequent employment, income, living

standards, behaviours and mental health (Ref. 19-6).

19.5.2. As outlined in Chapter 9: Socio-economics, the Proposed Development and

associated infrastructure is expected to lead to an additional 840 FTE jobs during

peak construction.

19.5.3. In general, the initial job and income growth for the construction workforce

associated with employment at the Proposed Development translates into further

spending and rising incomes throughout the community. This can have positive

impacts on individuals, families, neighbourhoods and communities, for instance,

in decreased crime, drugs, and family disruption, and increased and

strengthened security, education, healthcare for the infirm and elderly. Based on

the assessment provided in Chapter 9: Socio-economics, the effect on public

health is considered to be beneficial.

19.5.4. In addition to the direct construction employment generated by the Proposed

Development there would be an increase in local employment arising from

indirect and induced effects of the construction activity. Employment growth

would arise locally through manufacturing services and suppliers to the

construction process (indirect or supply linkage multipliers). Additionally, part of

the income of the construction workers and suppliers would be spent in the

Bristol Travel To Work Area, generating further employment. Therefore based on

the assessment in Chapter 9: Socio-economics, the effect on public health is

considered to be beneficial.


May 2014 Page 19-13

Operational Phase

19.5.5. It is envisaged that the plant will have a design life of 30 years, with an operating

life possibly beyond this.

Traffic and Transport

19.5.6. Chapter 10: Traffic and Transport indicates that the effect of traffic flows during

operation is predicted to be negligible following mitigation. It identifies that travel

plan measures such as shuttle bus services and car sharing schemes will be

introduced and this will be outlined in the Travel Plan that is submitted along with

the final ES.

19.5.7. The delivery of a new PROW is anticipated to lead to a minor beneficial effect on

pedestrian and cyclist amenity. Therefore there is anticipated to be an overall

beneficial effect on the public health of the receptors in relation to increased

opportunities of cycling and walking.

Air Quality

19.5.8. Chapter 11: Air Quality models the likely effect of operational emissions from the

Proposed Development, including the increase in concentrations due to

additional traffic flows. The chapter concluded the impact of air quality will be

negligible.

19.5.9. The maximum process contribution of NO2 from any of the operational scenarios

results in a ‘low’ change in the annual mean concentration at four of the identified

receptors. The ambient concentration at these receptors is well below the

objective with the Proposed Development, therefore the significance of the effect

at these receptors is predicted to be negligible. The magnitude of change at all

other human health receptors is very low and the significance of effect is also

negligible.

19.5.10. The magnitude of change in annual mean NO2 concentration at the identified

nearest AQMAs from the Proposed Development is ‘very low’; therefore the

significance of effect at the AQMAs is considered to be negligible.

19.5.11. The maximum short-term predicted concentration of NO2 at the worst affected

receptor (the PROW immediately south of Proposed Development) represents

less than 7% of the daily mean national Air Quality Strategy objective and is

considered to be insignficiant according to EA guidance. The Proposed

Development short term contribution to hourly mean NO2 is considered to have a

negligible effect on human health.


May 2014 Page 19-14

19.5.12. The maximum short-term and long term process contributions of PM10, CO and

other pollutants at the worst affected receptors represent ‘very low’ changes in

the concentration over the appropriate averaging periods, which are considered

to have a negligible effect on human health.

19.5.13. Based on this conclusion the effect on public health is considered to be

negligible.

Noise and Vibration

19.5.14. Chapter 12: Noise and Vibration models operational noise for the Proposed

Development. With mitigation in place to meet the specified reduction in

equipment noise levels during design, the residual effect from the operation of

the Proposed Development is predicted to be negligible for all receptors. Based

on the conclusions presented in Chapter 11: Noise and Vibration, the effect on

public health from operational noise and vibration is therefore considered to be

negligible.

Ground Conditions

19.5.15. There are not anticipated to be any potential effects on human health from

ground conditions during operation.

Socio-economics

19.5.16. Maintenance, administrative roles and shift workers will be required in operational

phase of the Proposed Development as outlined in Chapter 9: Socio-economics.

Up to 40 jobs FTE are expected to be created by the operational Proposed

Development, which is likely to have a number of positive effects for those

employed. Based on the assessment described in Chapter 9: Socio-economics

the effect on public health is anticipated to be beneficial.

Electromagnetic Fields (EMF) and Health

19.5.17. The UK Government sets guidelines for exposure to EMF on the advice from the

HPA’s Centre for Radiation, Chemical and Environmental Hazards. Guidelines

published by the International Commission on Non-Ionising Radiation Protection

(ICNIRP) (Ref. 19-7) were adopted by the UK Government in 2004 and a further

code of practice has been produced by Department of Energy and Climate

Change (DECC) (Ref. 19-8). Furthermore the World Health Organisation (WHO)

has also produced a fact sheet on EMF and Public Health (Ref. 19-9).These

guidelines include reference and permitted levels of exposure as detailed in the

following section.


May 2014 Page 19-15

19.5.18. The ICNIRP “reference levels” for the public are:

100 µT for magnetic fields; and

5,000V/m for electric fields.

19.5.1. Both the transmission and distribution assets associated with the Proposed

Development have each been assessed for compliance against Government

guideline limits documented in NPS EN-5 (Ref. 19-10). A summary of the

reference levels in comparison to typical ground-level UK field levels from

overhead power lines (Ref. 19-11) are shown in Table 19-5.

Table 19-5: ICNIRP Reference Levels vs Typical Ground-level UK Field Levels from

Overhead Power Lines

Electromagnetic Fields Magnetic Electric

ICNIRP “reference levels” for the public

100 µT 5,000 V/m

275kV- 400kV 5-10 µT 3,000 – 5,000 V/m

132kV 0.5-2 µT 1,000 – 2,000 V/m

33kV- 11kV 0.2 -0.5 µT 200 V/m

19.5.2. A number of existing buried and above ground services are already present on

the Proposed Development Site with 400kV, 132kV and 11kV OHLs crossing the

CCR Site in an east to west direction, and with five pylons on the CCR Site.

19.5.3. The Proposed Development includes the installation of new 400kV electrical

connection approximately 440m long and routed through the existing Seabank 1

& 2 station to Seabank Substation. The proposed connection will be either

underground and/or on a cable rack approximately 2m above ground. In addition,

the existing 11kV connection will be routed underground in a north to south

direction across the eastern part of the Generating Station Site as part of the


19.5.4. The strength of a magnetic field decreases dramatically with increasing distance

from the source (Ref. 19-10). The nearest residential properties are located more

than 1.1km from the Proposed Development, with existing overhead lines much

closer than this currently. Therefore the effect of the proposed electrical

connection is likely to be indiscernible from background levels at these residential

dwellings.

19.5.5. The strength of a magnetic field will be higher at the local PROW, however

exposure would be short-term and still approximately 400m from the proposed

electrical connection (including the proposed PROW), which is sufficient to

render its effects negligible. As mentioned above, the proposed connection may


May 2014 Page 19-16

be underground, which would further reduce any potential effect, as well as

moving the 11kV connection underground which currently runs close to one of

the PROW in Crook’s Marsh.

19.5.6. Taking the above into account, and the fact the Proposed Development will be

constructed and operated in compliance with the ICNIRP Guidelines on EMF,

there are negligible residual impacts from EMF associated with the operation of

the project. Based on this conclusion the effect of EMFs on public health is


Safety and Emergency Planning

19.5.7. As outlined in Chapter 4: Project Description the Applicant will develop an

Emergency Planning and Response Management Plan similar to that used for

Seabank 1 & 2 site such that emergency planning and response control

measures are implemented to:

• Mitigate the potential effects to persons, environment, assets or company

reputation;

• Respond to catastrophic plant and process incidents such as fires,

explosions, release of hazardous substances or large releases of energy;

• Respond to external incidents which have the potential to cause

incidents described above e.g. nearby facility emergency, flood,

malevolent actions, earthquake or aircraft crash; and

• Communicate with stakeholders such as neighbours, media or

regulators.

19.5.8. The Emergency Planning and Response Management Plan will be tailored to the

Proposed Development. This Plan is applied at all operational SSE sites and

includes any site specific requirements.

19.5.9. Fire safety methods will build upon those methods already practiced at the

Seabank 1 & 2 site. Fire safety management is applicable to the entire

Generation Station Site and is further addressed in this section.

19.5.10. Following implementation of these safety measures, the risk of an emergency

onsite affecting worker or community health is considered to be negligible.


19.5.11. It is not anticipated that the decommissioning phase would have the potential to

cause any significant health issues. The significance of effects associated with

decommissioning are expected to be similar to construction, albeit for a slightly

shorter duration.


May 2014 Page 19-17

19.5.12. The greatest risk of health effects is to workers onsite, although following

adequate health and safety measures as outlined in Chapter 10; Ground

Conditions, this too is expected to be of negligible significance.


19.6.1. A summary of residual effects for both the construction and operational phase is

presented in Table 19-6.

Table 19-6: Summary of Residual Effects (post-mitigation)

Assessment Chapter Topic Impact Geographic Scale

Health effect

category

Construction phase

Chapter 11: Air Quality; Chapter 12: Noise and Vibration

Disturbance and nuisance

Impacts from dust, emissions, road traffic; onsite machinery

Local; Regional

Negligible

Chapter 10: Traffic and Transport

Transport and access

Impact on severance, driver delay, pedestrian and cyclist delay, fear and intimidation, accident and safety.

Local Negligible


Impact on pedestrian and cyclist amenity – creation of new PROW

Local Beneficial

Chapter 13: Ground Conditions; Chapter 14: Flood Risk, Hydrology and Water Resources

Contamination Pathways

Impacts from contaminated land; pollution. Local Negligible

Chapter 9: Socio-economics

Socio-economics and employment

Additional employment Local; Regional

Beneficial

Operational Phase

Chapter 10: Traffic and Transport; Chapter 11: Air Quality; Chapter 12: Noise and Vibration

Disturbance and nuisance

Impacts from dust, road traffic; onsite machinery

Local; Regional

Negligible

Chapter 13: Ground Conditions; Chapter 14: Flood Risk, Hydrology and Water Resources

Contamination Pathways

Impacts from re-use of soils, importation of materials to site Local

Negligible

Chapter 10: Traffic and Transport


Impact on severance, driver delay, pedestrian and cyclist delay, fear and intimidation, accident and safety

Local Negligible


May 2014 Page 19-18

Assessment Chapter Topic Impact Geographic Scale

Health effect

category

Chapter 9: Socio-economics

Socio-economics and employment

Impact of employment and local economy

Local; Regional

Beneficial

Chapter 19: Health Electromagnetic Fields (EMF) and Health

Impact of EMF from overhead and underground lines

Local Negligible


Safety and Emergency Planning

Emergency event onsite such as a fire

Local; Regional

Negligible

19.6.2. Based on this assessment it is expected that the Proposed Development will

have a negligible effect on the health of the receptors following mitigation, with

the exception of two beneficial effects:

• A beneficial effect during operation associated with the production of a

new PROW, which will help encourage walking and cycling by local

residents and workers in Severnside;

• Beneficial effects during construction and operation associated with

employment generation, which is recognised by the Marmot Review as

having potential health benefits.



infrastructure in combination with other developments in the area, as outlined in

Chapter 7: Assessment Methodology, and their potential to cause cumulative

health effects.

19.7.2. There are a number of cumulative schemes in the local area that have the

potential to effect health, such as the Hinkley C Connection project which

comprises a long-distance 400KV OHL. However, the potential for cumulative

EMF effects has not been considered further given that the Proposed

Development has a negligible contribution to changes in EMF.

19.7.3. The key aspect with the potential for cumulative effects is considered to be air

quality, which is discussed further below. Given the distance from the Proposed

Development Site to the nearest residential dwellings, it is not expected that

there would be cumulative noise effects. It is also anticipated that these

developments when considered along with the Proposed Development should

not give rise to increased effects from traffic and transport, ground conditions and

socio-economics.


May 2014 Page 19-19

19.7.4. The Severnside Energy Recovery Centre and Avon Power Station schemes are

sufficiently close to the Proposed Development and of sufficient scale to have the

potential to contribute to cumulative effects to air quality on identified receptors,

according to Chapter 11: Air Quality. These have been modelled together with

the Proposed Development in Chapter 11: Air Quality to determine the overall

potential cumulative effect. The predicted concentrations from cumulative source

air quality modelling indicate that the additional contributions from the Proposed

Development are unlikely to result in exceedance of hourly or annual mean

National Air Quality Strategy objectives at the worst-affected human health

receptors. For this reason the effects on public health from cumulative air quality

are considered to be negligible.


19.8.1. The technical chapters in this PEI Report have identified a number of impact and

effects yet to be determined as part of the EIA process, which will need to be

considered in the updated health chapter as part of the ES.

19.8.2. The scheme design may be subject to change prior to submission of the final

DCO application. Any changes that lead to differing or new impacts and effects

will be highlighted within the final ES, along with the reasons for the change.


preparation of this PEI Report and the final ES; aspects such as air quality and

noise conditions are dynamic and evolve over time. The Proposed Development

Site is currently subject to excavation, top soil stripping, and levelling in certain

areas in order for third parties to deliver the Spine Access Road and new channel

for the Red Rhine, which are discussed in Chapter 2: The DCO and EIA Process

and Chapter 7: Assessment Methodology. A haul road is also being constructed





Development.






May 2014 Page 19-20

19.9. References

Ref. 19-1 Healthy Urban Development Unit (2013) Rapid Health Impact

Toolhttp://www.healthyurbandevelopment.nhs.uk/wp-

content/uploads/2013/12/HUDU-Rapid-HIA-Tool-Jan-2013-Final.pdf

Ref. 19-2 Scott-Samuel (2001) Merseyside Guidelines for Health Impact

Assessment

Ref. 19-3 Public Health England (2013) Local Health Profiles:

www.apho.org.uk

Ref. 19-4 South Gloucestershire JSNA (2013)

http://hosted.southglos.gov.uk/oaof/documents/jsna/South%20Glou

cestershire%20JSNA%202013%20Section%203/Section%203.6%2

0Environment.pdf

Ref. 19-5 Bristol JSNA (2012)

http://www.bristol.gov.uk/sites/default/files/documents/health_and_a

dult_care/health/JSNA%204.%20Health%2C%20Wellbeing%20%26

%20Inequalities%20_v7_.pdf

Ref. 19-6 The Marmot Review (2010) Fair Society, Healthy Lives

http://www.instituteofhealthequity.org/projects/fair-society-healthy-

lives-the-marmot-review

Ref. 19-7 ICNRP (1998) Guidelines for Limiting Exposure to time-varying

electric, magnetic and electromagnetic fields (up to 300 GHz).

Health Physics 74 (4): 494-522.

Ref. 19-8 DECC Codes of Practice (2012)

https://www.gov.uk/government/uploads/system/uploads/attachment

_data/file/37447/1256-code-practice-emf-public-exp-guidelines.pdf

Ref. 19-9 WHO (2013) Electromagnetic fields and public health

http://www.who.int/peh-emf/publications/facts/fs322/en/

Ref. 19-10 National Policy Statement for Electricity Networks Infrastructure

(EN-5)

https://www.gov.uk/government/uploads/system/uploads/attachment

_data/file/37050/1942-national-policy-statement-electricity-

networks.pdf

Ref. 19-11 Energy Networks Association (2013) Engineering Recommendation

G92

http://www.energynetworks.org/modx/assets/files/electricity/she/emf

s/EMF_The_Facts_260613.pdf

Seabank 3 PEI Report – Chapter 20 Cumulative Effects

May 2014 Page 20-1

20. Cumulative Effects

20.1. Introduction

20.1.1. This chapter of the PEI Report assesses the effect of the Proposed Development

and associated infrastructure in combination with the potential environmental and

socio-economic effects of other consented developments in the area.

20.1.2. Cumulative effect interactions can occur as either interactions between effects

associated with just one project or interactions between the effects of a number

of projects in an area. As a result, two types of cumulative effect interaction have

been considered which are as follows:

• The combined effect of individual effects arising as a result of the

Proposed Development and associated infrastructure, for example

effects in relation to atmospheric emissions from the stacks and HGV

deliveries affecting a single receptor; and

• The effects of the Proposed Development and associated infrastructure

along with other development schemes which may, on an individual

basis be insignificant but, together (i.e. cumulatively), have a significant

effect.

20.1.3. In some EIA guidance documents, these two types of cumulative impact

interactions are referred to as ‘Type 1’ and ‘Type 2’ cumulative effects

respectively. Both types have been considered within each of the technical

chapters of this PEI Report.

20.1.4. Details of the other schemes considered within the cumulative effects

assessment can be found in Table 20-1 below and are discussed within Chapter

7: Assessment Methodology.

20.2. Legislation and Planning Policy Context

20.2.1. The requirement for cumulative impact assessment is clearly stated in the

relevant Directives and legislation as detailed below:

• European Directive 2011/92/EU (Ref. 20-1) on the assessments of

effects of certain public and private projects on the environment requires

the assessment of “the direct effects and any indirect, secondary,

cumulative, short, medium and long term, permanent or temporary,

positive and negative effects of the project”;

• Schedule 4 Part 1 of The Infrastructure Planning (Environmental Impact

Assessment) Regulations 2009 (as amended) (Ref. 20-2) requires “A

description of the likely significant effects of the development on the


May 2014 Page 20-2

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, resulting

from:

(1) The existence of the development;

(2) The use of natural resources;

(3) The emission of pollutants, the creation of nuisances and the

elimination of waste,

• and the description by the applicant of the forecasting methods used to

assess the effects on the environment”.

20.3. Assessment Methodology

20.3.1. Section 7.4.11 of Chapter 7: Assessment Methodology sets out the other

developments considered within the cumulative effect assessment, with their

locations illustrated on Figure 7-1, Volume III of this PEI Report.

20.3.2. The schemes included within the cumulative effect assessment have been

identified in consultation with SGC and BBC, and comprise those within a 6km

radius of the Proposed Development Site and which are more than 1ha in size.

20.3.3. Each technical specialist has reviewed the cumulative schemes to determine if

any could have potential cumulative effects with the Proposed Development and

associated infrastructure. Where no cumulative effects have been identified, this

is also stated.

20.3.4. Two types of cumulative effect interaction have been considered as part of this

assessment, which are discussed below.

Combined Effects – Type 1

20.3.5. The combination of predicted environmental effects resulting from a single

development on any one receptor that may collectively cause a greater (or

lesser) effect than each effect in isolation is referred to in this chapter as

‘combined effects’. An example could be the combination of atmospheric

emissions from the stacks and HGV deliveries affecting a single receptor

together, to cause a combined effect that is different to that assessed to occur

when each individual effect is considered in isolation.

Cumulative Effects – Type 2

20.3.6. Cumulative effects are those that accrue over time and space from a number of

developments. The effects of the Proposed Development are considered in


May 2014 Page 20-3

conjunction with the potential effects from other projects or activities that are both

reasonably foreseeable in terms of delivery (e.g. have planning consent or are in

the planning process) and are geographically located in a position where

environmental impacts could act together to create an effect that is of more (or

less) significance overall than the effect of individual schemes alone.

20.3.7. Operational impacts are generally long-term, and whilst construction impacts are

often temporary, they can be of a great magnitude. Consequently, when

cumulative effects that could be associated with construction at one site and

operation at another are considered the difference in duration and reversibility is

considered within the assessment.

Effect Assessment and Significance Criteria

20.3.8. There is no standard prescriptive method for assessing cumulative and combined

effects and the extent to which effects of other developments can be assessed

quantitatively depends on the level of information available about the

development. Such effects are, therefore, assessed by professional opinion,

although matrices and modelling are used where appropriate and where enough

information regarding the other proposed developments exists. Effects are

quantified where possible but where environmental assessment information

regarding other developments is not available or uncertain, the assessment is

necessarily qualitative.

20.3.9. When considering the cumulative effects of the Proposed Development together

with other developments, mitigation measures as set-out in Chapters 9 - 19 have

been taken into account i.e. only residual (after mitigation) effects are discussed

in this chapter. Consideration of combined effects generally follows the

methodology set out in the Chapters referenced.

20.3.10. Cumulative and combined effects are assessed to be neutral, minor (not

significant), moderate or major (significant).

20.3.11. In reporting significance, it is appropriate to also acknowledge the relative

contributions different projects make to a cumulative effect, and carefully

consider whether a cumulative effect occurs at all. A large scale project might be

predicted to result in significant effects in its own right for example. The

cumulative effects of such a project with a smaller proposed development that

does not have significant effects should not conclude significant cumulative

effects unless an effect of greater significance is assessed to occur.

Consequently, care is taken not to simply propagate such effects as being

cumulative, but rather to focus on the nature and scale to which genuine

cumulative effects might result.


May 2014 Page 20-4

20.3.12. Where applicable, the assessment considers all developments that have

potential for cumulative effects with the Proposed Development together, as a

worst case.

20.4. Combined Effects of Individual Effects -Type 1

20.4.1. The main Type 1 cumulative effect associated with the Proposed Development

and associated infrastructure is the combined effect of atmospheric emissions

from the stack and additional road traffic, as well as the combination of noise

emissions from the operational facility and HGV delivery traffic.

20.4.2. Chapter 11: Air Quality addresses this issue and demonstrates that, together,

there are no cumulative traffic and point source effects from the Proposed

Development as traffic impacts will occur during construction, while point source

impacts will occur during plant operation.

20.4.3. Chapter 12: Noise and Vibration demonstrates that the significance of operational

noise emissions is negligible to minor adverse at the worst affected dwellings,

regardless of whether HGV traffic is taken into account, and therefore is not


20.4.4. Specific mitigation measures for individual effects are addressed in the technical

chapters of this PEI Report. These measures will be incorporated into the CEMP.

20.5. Combined Effects of the Proposed Development with Other

Development Schemes – Type 2

20.5.1. As highlighted within the introduction to this chapter, the review of the combined

effects of the Proposed Development with other schemes (or ‘Type 2’ cumulative

effects) is presented within each of the technical chapters of this PEI Report.

20.5.2. Generally, it is not anticipated that the cumulative schemes would change the

significance of the predicted residual effects associated with the Proposed

Development and associated infrastructure. The exceptions to this, where

consideration of the cumulative schemes has increased the residual effects

identified within this PEI Report, are listed below in Table 20-1.

Table 20-1: Cumulative Effects of the Proposed Development with Other Development Schemes

Environmental

Aspect Potential for Cumulative Effect

Significance of

Cumulative Effects

Chapter 9:

Socio-

Economics

The combined effect of the Proposed Development with the

cumulative schemes in terms of operational jobs on the Bristol

Travel to Work Area (TTWA) and the South West economy.

Moderate

Beneficial


May 2014 Page 20-5

Environmental

Aspect Potential for Cumulative Effect

Significance of

Cumulative Effects

Chapter 10:

Transport and

Access

The combined effect of construction traffic from the Proposed

Development with the cumulative schemes. The assessment

incorporates a number of conservative assumptions and is

based on the peak month of construction. The rest of the

construction period is expected to lead to less traffic and

deliveries are likely to be timed deliberately to avoid the peak

hours, thereby reducing the significance of effect.

Minor Adverse

(with the majority

of the construction

period negligible)

Chapter 11:

Air Quality

The combined effect of operational emissions from the

Proposed Development with the cumulative schemes at human

health and ecological receptors (including the worst-affected

area of the Severn Estuary SAC/SPA/Ramsar/SSSI).

Minor Adverse

Chapter 12:

Noise and

Vibration

The combined effect of operational noise emissions upon

residential receptors from the Proposed Development with the

cumulative schemes.

Minor Adverse

Chapter 15:

Archaeology

The combined effect on archaeological features from the

construction of the Proposed Development with the cumulative

schemes.

Minor Adverse

The combined effect on heritage features from the operation of

the Proposed Development with the cumulative schemes. Minor Adverse

Chapter 17:

Landscape

and Visuals

The combined effect of visual effects (at Year 15) from the

Proposed Development with the cumulative schemes. Minor Adverse

20.5.3. The only residual effect to have been elevated to a significant effect as a result of

considering the cumulative schemes is the moderate beneficial effect associated

with the job creation attributed to the operational Proposed Development and

cumulative schemes. The Proposed Development is predicted to generate a

minor benefit in isolation.

20.5.4. It is not expected that any other residual effects attributed to the Proposed

Development and associated development would change when taking into

account these cumulative schemes.

20.6. References

Ref. 20-1 European Directive 2011/92/EU

Ref. 20-3 The Infrastructure Planning (Environmental Impact Assessment)

Regulations 2009 (as amended)

Seabank 3 PEI Report – Chapter 21 Residual Effects

May 2014 Page 21-1

21. Residual Effects

21.1. Introduction

21.1.1. This chapter of the PEI Report provides a summary of the ‘residual effects’ associated with the Proposed Development and associated development, which are those effects that remain following the implementation of the mitigation measures presented in the preceding technical chapters.

21.1.2. Mitigation measures relate to each of the key phases (enabling works and construction of the plant; operation) of the Proposed Development and associated infrastructure, and are discussed in full in the relevant technical chapters of this PEI Report. In addition, each technical chapter also contains a detailed consideration of both positive (beneficial) and negative (adverse) residual effects arising.

21.1.3. The significance criteria applied to these effects is outlined in Chapter 7: Assessment Methodology of this PEI Report, and its application is also discussed within each of the technical chapters.

21.2. Background

21.2.1. Preparation of the EIA and evolution of the design of the Proposed Development have been undertaken in parallel, and as such, many mitigation measures have already been incorporated within the design parameters to eliminate adverse environmental and social effects before they occur – a process termed Impact Avoidance. These include, for example, determining the appropriate stack height to avoid significant effects on local air quality and designated sites, as well as HGV vehicle restrictions so as to avoid adverse effects to nearby communities and habitat sites

21.2.2. A CMS and CEMP will be prepared and approved by the local councils prior to the onset of the demolition and construction phase to maintain consideration of environmental effects beyond the planning stage of the Proposed Development. This will incorporate the commitments made within the PEI with regard to mitigating against potentially adverse effects throughout the enabling works, and construction phase (refer to Chapter 5: Enabling Works and Construction of this PEI Report).

21.2.3. The CEMP will address all relevant environmental issues including: noise and vibration, waste management, air emissions, hours of working and neighbourhood liaison.

21.2.4. Chapter 20: Cumulative Effects of this PEI Report addresses the potential effects taking into account the other nearby schemes identified in Chapter 7: Assessment Methodology.

21.3. Summary of Residual Effects

21.3.1. Table 21-1 provides a summary of the identified residual effects associated with the Proposed Development and associated infrastructure in the construction and operational phases.


May 2014 Page 21-2


Chapter No. Project Phase Description Effect

Significance

9. Socio

Economics

Construction

Employment generation and supply chain

benefits during the construction phase

(direct, indirect and induced effects)

Moderate

Beneficial

Leisure, Recreation and Tourism Negligible

Operation

Employment generation and supply chain

benefits during the operational phase Minor Beneficial

Land use and Public Rights of Way (PROW) Minor Beneficial

Leisure, Recreation and Tourism Negligible

10. Traffic

and

Transport

Construction

Effects on Severance, Driver delays,

Pedestrian/cyclist delay, Fear and

intimidation, Accident and safety

Negligible

Effect on pedestrian/cyclist Amenity Negligible

Operation

Effects on Severance, Driver delays,

Pedestrian/cyclist delay, Fear and

intimidation, Accident and safety

Negligible

Effect on pedestrian/cyclist Amenity Minor Beneficial

11. Air

Quality

Construction

Exhaust emissions from construction site

plant/equipment Negligible

Exhaust emissions associated with HGV road

movements Negligible

Construction dust emissions Negligible

Operation

Point source emissions associated with the

operational development on human health Negligible

Point source emissions associated with the

operational development on ecosystems Negligible

12. Noise

and Vibration

Construction

Effect of construction activities onsite on

residential receptors Negligible

Effect of construction activities onsite on

ecological receptors Minor Adverse

Construction traffic noise Negligible

Construction vibration Negligible

Operation Operational noise (single or multi shaft) Negligible to

Minor Adverse


May 2014 Page 21-3


Significance

13. Ground

Conditions

Construction

Soil and groundwater contamination Negligible

Ground Gas Negligible to Minor Adverse

Underground Structures and Unexploded Ordnance

Negligible

Storage of potentially contaminating

materials and accidental spillage Negligible

Operation

Accidental release of contaminating materials

and accidental spillage Minor Adverse

Degradation of soil and groundwater conditions

Negligible

14. Flood

Risk,

Hydrology

and Water

Resources

Construction

Water use and potential to affect water

quality Minor Adverse

Fluvial/tidal flood risk to third party land

associated with raising the Proposed

Development Site

Minor adverse

Increase in surface water runoff Minor Adverse

Operation

Water use and potential to affect water

quality Minor Adverse

Fluvial/tidal flood risk to the Proposed

Development Site following land raising Major Beneficial

Fluvial/tidal flood risk to third party land

associated with raising the Proposed

Development Site

Minor adverse

Increase in surface water runoff Minor Beneficial

15.

Archaeology

and Cultural

Heritage

Construction Effects on buried archaeology Minor Adverse

Effects on the setting of heritage assets Minor Adverse

Operation Effects on buried archaeology Negligible

Effects on the setting of heritage assets Minor Adverse

16. Ecology

Construction

Effects on designated sites offsite Negligible to

Minor Adverse

Effects on habitat integrity onsite Minor Adverse

Effect on Bats and flora Negligible

Effect on Breeding Birds, Non-breeding birds, Reptiles

Minor Adverse


May 2014 Page 21-4


Significance

Operation

Effects on designated sites offsite Negligible to

Minor Adverse

Effects on habitat integrity onsite Minor Adverse

Effect on Bats, breeding birds and flora Negligible

Effect on non-breeding birds and reptiles Minor adverse

17.

Landscape

and Visual

Impact

Construction

Landscape effects of construction Negligible to

Minor Adverse

Visual effects (all receptors except Crook’s

Marsh)

Negligible to

Minor Adverse

Visual effects on Crook’s Marsh PROW

(Receptor 10a)

Moderate

Adverse

Operation

Landscape effects of operation Negligible to

Minor Adverse

Visual effects (all receptors except Crook’s

Marsh)

Negligible to

Minor Adverse

Visual effects of operation in Year 1 from

PROW on Crook’s Marsh (Receptor 10a)

Moderate

Adverse

Visual effects of operation in Year 15 from

PROW on Crook’s Marsh (Receptor 10a) Minor Adverse

19. Health

Construction

Disturbance and nuisance from dust,

emissions, road traffic; onsite machinery, and

effects from contaminated land, pollution

Negligible

Effects on health arising from socio-economic

impacts and employment generation Minor Beneficial

Operation

Disturbance and nuisance to nearby

receptors from dust, emissions, road traffic;

onsite machinery

Negligible

Impact of EMF from overhead and underground lines

Negligible

Effects on health arising from socio-economic

impacts and employment generation Minor Beneficial

Safety and emergency planning Negligible

Provision of a new PROW to encourage

recreational activities and commuting by

cycling/walking

Minor Beneficial


May 2014 Page 21-5

21.4. Summary and Conclusions

Construction Phase

21.4.1. The residual effects associated with enabling works and construction of the Proposed Development and associated infrastructure are considered short term, temporary and reversible. These effects have been assessed as being predominantly negligible or minor adverse.

21.4.2. No major effects have been identified within this PEI Report which would be considered significant; however the PEI Report has concluded that the Proposed Development will result in significant (moderate) beneficial socio-economic effects through the creation of jobs during the construction phase, whilst a moderate adverse visual effect is predicted for walkers on the PROW on Crook’s Marsh (Receptor 10a), albeit this will be temporary in duration and it is not a well-used PROW currently (because it ceases at the Proposed Development Site boundary).

21.4.3. A number of mitigation measures (or actions) have been outlined in the technical chapters which will be implemented during the enabling works and construction to ensure that these effects are minimised. These will be incorporated into the CEMP, which will be agreed with BCC and SGC prior to commencement of site works.

Operational Phase

21.4.4. The operational effects of the Proposed Development are predominantly negligible or minor. Moderate and major effects are discussed below.

21.4.5. A temporary moderate adverse visual effect is expected on users of the PROW on Crook’s Marsh (Receptor 10a) during the early years of operation, as the woodland blocks planted along the southern boundary would not have fully established by Year 1 of operation to filter views. Following growth of the woodland blocks and other planting the effect on users of this PROW is considered to reduce to minor.

21.4.6. A significant major beneficial effect on flood risk has been identified as a result of the proposed land raising, which will protect the Proposed Development Site from extreme flood events, without causing a significant adverse effect on neighbouring land through the displacement of this water.

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