A303 Stonehenge Amesbury to Berwick Down Preliminary Environmental Information Report February 2018 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report Table of Contents Chapter Pages 1 Introduction 7 1.1 Overview and need for the proposed scheme 7 1.2 The purpose of the report 7 1.3 Legislative and policy framework 8 1.4 The Applicant 10 1.5 Stakeholder engagement 10 1.6 Structure of this PEI Report 11 1.7 The EIA team 13 1.8 Next steps 13 2 The Proposed Scheme 15 2.1 Project location 15 2.2 Description of the proposed scheme 15 2.3 Construction 25 3 Assessment of Alternatives 31 3.1 Scheme history 31 3.2 Selection of the proposed scheme 31 3.3 Development of the proposed scheme 34 3.4 Appraisal of options presented for consultation 35 4 Environmental Assessment Methodology 40 4.1 General approach 40 4.2 Study area and site boundary 41 4.3 Existing baseline and future conditions 42 4.4 Potential significant effects and mitigation 42 4.5 Major events 46 4.6 Human health 47 5 Air Quality 49 5.1 Introduction 49 5.2 Stakeholder engagement 49 5.3 Assessment assumptions and limitations 50 5.4 Study area 51 5.5 Baseline conditions 52 5.6 Potential impacts 55 5.7 Design, mitigation and enhancement measures 56 5.8 Assessment of effects 57 3 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report 5.9 Corridors for utility connections 61 6 Cultural Heritage 62 6.1 Introduction 62 6.2 Stakeholder engagement 62 6.3 Assessment assumptions and limitations 63 6.4 Study area 63 6.5 Baseline 64 6.6 Potential impacts 70 6.7 Design, mitigation and enhancement measures 71 6.8 Assessment of effects 72 6.9 Corridors for utility connections 77 7 Landscape and Visual Effects 79 7.1 Introduction 79 7.2 Stakeholder engagement 79 7.3 Assessment assumptions and limitations 80 7.4 Study area 80 7.5 Baseline conditions 80 7.6 Potential impacts 94 7.7 Design, mitigation and enhancement measures 95 7.8 Assessment of effects 98 7.9 Corridors for utility connections 101 8 Biodiversity 104 8.1 Introduction 104 8.2 Stakeholder engagement 104 8.3 Assessment assumptions and limitations 105 8.4 Study area 106 8.5 Field surveys 106 8.6 Biodiversity receptors 109 8.7 Biodiversity enhancement measures and opportunities 141 8.8 Assessment of effects 142 8.9 Corridors for utility connections 143 9 Noise and Vibration 146 9.1 Introduction 146 9.2 Stakeholder engagement 146 9.3 Assessment assumptions and limitations 147 9.4 Study area 147 9.5 Baseline conditions 148 4 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report 9.6 Potential impacts 150 9.7 Design, mitigation and enhancement measures 150 9.8 Assessment of effects 151 9.9 Corridors for utility connections 154 10 Geology and Soils 156 10.1 Introduction 156 10.2 Stakeholder engagement 156 10.3 Assessment assumptions and limitations 156 10.4 Study area 157 10.5 Baseline conditions 157 10.6 Potential impacts 163 10.7 Design, mitigation and enhancement measures 166 10.8 Assessment of effects 169 10.9 Corridors for utility connections 170 11 Road Drainage and the Water Environment 172 11.1 Introduction 172 11.2 Stakeholder engagement 172 11.3 Assessment assumptions and limitations 173 11.4 Study area 173 11.5 Baseline conditions 174 11.6 Potential impacts 188 11.7 Design, mitigation and enhancement measures 189 11.8 Assessment of effects 192 11.9 Corridors for utility connections 205 12 Materials 206 12.1 Introduction 206 12.2 Stakeholder engagement 206 12.3 Study area 207 12.4 Baseline conditions 207 12.5 Potential impacts 209 12.6 Design, mitigation and enhancement measures 210 12.7 Assessment of effects 211 13 People and Communities 213 13.1 Introduction 213 13.2 Stakeholder engagement 213 13.3 Assessment assumptions and limitations 213 13.4 Study area 214 5 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report 13.5 Baseline conditions 214 13.7 Design, mitigation and enhancement measures 221 13.8 Assessment of effects 222 13.9 Corridors for utility connections 224 14 Climate 226 14.1 Introduction 226 14.2 Stakeholder engagement 226 14.3 Study area 227 14.4 Baseline conditions 227 14.5 Potential impacts 229 14.6 Design, mitigation and enhancement measures 231 14.7 Assessment of effects 233 15 Cumulative, In-combination and Project-wide Effects 236 15.1 Introduction 236 15.2 Cumulative effects 236 15.3 In-combination effects 239 15.4 Project-wide effects 240 15.5 Human Health 240 16 Summary of effects 242 References 245 Glossary 253 Abbreviations 256 Figures 260 Appendix 1.A Competent Expert Table 263 Appendix 7.A Schedule of Representative Viewpoints (VP) to be read with Figure 7.4. 267 Appendix 10.A Land Contamination Methodology Tables 271 Appendix 11.A Environment Agency Surface Water Flood Risk Map 273 Appendix 11.B Environment Agency Product 4 Information 274 6 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report 1 Introduction 1.1 Overview and need for the proposed scheme 1.1.1 The A303/A358 corridor is a vital connection between the South West and the South East. While most of the road is now dual carriageway, there are still over 35 miles (56km) of single carriageway. These sections act as bottlenecks for users of the route resulting in congestion, particularly in the summer months and at weekends. This causes delays to traffic travelling between the M3 and the South West and increases the risk of accidents. 1.1.2 The A303 Stonehenge – Amesbury to Berwick Down Scheme (the proposed scheme) is part of a wider package of proposals for the A303/ A30 / A358 corridor designed to transform connectivity to and from the South West by creating a high-quality dual-carriageway along the corridor. The A303 / A30 / A358 Corridor improvements were identified in the 2016-2021 National Infrastructure Delivery Plan as one of the country’s top five projects or programmes within the road sector. 1.1.3 The existing A303 passes through the Stonehenge section of the Stonehenge, Avebury and Associated Sites World Heritage Site (the WHS), passing approximately 165 metres from the Stonehenge monument itself (hereafter referred to as the Stones). It is noted that the WHS comprises two distinct components – Avebury to the north and Stonehenge to the south. The proposed scheme crosses the Stonehenge component only (see Figure 1.1) and all subsequent references to “the WHS” in this Preliminary Environmental Information Report refer to the Stonehenge component. 1.1.4 Objectives for the proposed scheme have been formulated both to address identified problems and to take advantage of the opportunities that new infrastructure would provide. The objectives are defined in the Department for Transport’s (DfT’s) Client Scheme Requirements (CSRs) which respond directly to the need for change: a) Transport – To create a high quality reliable route between the South East and the South West that meets the future needs of traffic; b) Economic growth – To enable growth in jobs and housing by providing a free-flowing and reliable connection between the South East and the South West; c) Cultural heritage – To help conserve and enhance the World Heritage Site and to make it easier to reach and explore; and d) Environment and community – To improve biodiversity and provide a positive legacy for nearby communities. 1.2 The purpose of the report 1.2.1 This document is a Preliminary Environmental Information Report (“PEI Report”) which presents a description of the proposed scheme, the likely significant environmental effects based on the preliminary environmental information available at the time, measures to avoid or reduce such effects and the 7 A303 Stonehenge – Amesbury to Berwick Down Preliminary Environmental Information Report alternatives considered. This is to support consultees in developing an informed view of the likely significant environmental effects of the proposed scheme. 1.2.2 We are continuing to gather environmental information, identifying the potential impacts of the proposed scheme, and developing measures to avoid or reduce adverse impacts - a process known as environmental impact assessment (EIA).The results of the full EIA will be presented in an Environmental Statement (ES) submitted with the required Development Consent Order (DCO) application. 1.2.3 This PEI Report has been prepared to assist consultees in understanding the potential impacts of the proposed scheme and the mitigation measures currently proposed. It forms part of the consultation material provided for the statutory consultation process under the Planning Act 2008 (as amended, including by The Highway and Railway (Nationally Significant Infrastructure Project) Order 2013) (Ref 1.1) (PA 2008). Further details are provided under sub-section 1.7 Next Steps. 1.3 Legislative and policy framework Planning Act 2008 1.3.1 The proposed scheme is defined as a Nationally Significant Infrastructure Project (NSIP) under Section 14(1)(h) and Section 22 of the PA 2008 by virtue of the fact that: a) it comprises the construction of a highway; b) the highway to be constructed is wholly in England; c) the Secretary of State is the highway authority for the highway; and d) the speed limit for any class of vehicle on the highway is to be 50 miles per hour or greater, and the area for the construction of the highway is greater than 12.5 hectares. 1.3.2 In accordance with the legislation, a DCO is required to allow the construction and operation of the proposed scheme.