Dorset AONB, Overhead Line
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VISUAL IMPACT PROVISION Dorset AONB, Overhead Line Scoping Report Final Draft May 2016 Front Cover: 4YA overhead transmission line, near Winterbourne Abbas, Dorset AONB Contents 1 Introduction 7 Proposed Scheme Overview 7 VIP Subsection and Overview of Area 7 Legislative Framework 12 Habitats Regulations Assessment 12 General Assessment Methodology 13 2 Scheme Description 19 Construction, Operation and Decommissioning 19 Programme 23 3 Planning Policy 25 Introduction 25 National Planning Policy 25 Local Planning Policy 26 4 Consultation 27 Introduction 27 Ongoing Stakeholder Engagement 28 Wider Engagement 29 5 Landscape and Visual 31 Introduction 31 Legislation and Policy 32 Baseline Environment 33 Potential Impacts 37 Proposed Assessment Methodology 39 Proposed Mitigation Measures 42 Issues to be Scoped Out 43 6 Ecology 45 Introduction 45 Legislation and Policy 45 Consultation 46 Baseline Environment 46 Potential Impacts 56 Proposed Assessment Methodology 57 Proposed Mitigation Measures 65 Issues to be Scoped Out 67 7 Archaeology and Cultural Heritage 69 Introduction 69 Legislation and Planning Policy 69 Baseline Environment 69 Potential Impacts 73 Proposed Assessment Methodology 73 Proposed Mitigation Measures 77 Issues to be Scoped Out 77 Dorset AONB: Visual Impact Provision 3 May 2016 Scoping Report 8 Water Resources 79 Introduction 79 Legislation and Policy 81 Baseline Environment 81 Potential Impacts 83 Proposed Assessment Methodology 84 Proposed Mitigation Measures 85 Issues to be Scoped Out 85 9 Geology, Soils and Contaminated Land 87 Introduction 87 Legislation and Policy 87 Baseline Environment 89 Potential Impacts 92 Proposed Assessment Methodology 93 Proposed Mitigation Measures 94 Issues to be Scoped Out 94 10 Agriculture and Land Use 95 Introduction 95 Legislation and Policy 95 Baseline Environment 95 Potential Impacts 96 Proposed Assessment Methodology 98 Proposed Mitigation Measures 102 Issues to be Scoped Out 103 11 Air Quality 105 Introduction 105 Legislation and policy 105 Baseline Environment 108 Potential Impacts 108 Proposed Assessment Methodology 109 Proposed Mitigation Measures 109 Issues to be Scoped Out 110 12 Electric and Magnetic Fields 111 Introduction 111 Legislation and Policy 111 Potential Impacts and Conclusion 113 Potential Impacts and Conclusion 113 13 Traffic and Transport 115 Introduction 115 Legislation and Policy 115 Baseline Environment 116 Potential Impacts 116 Proposed Assessment Methodology 118 Proposed Mitigation Measures 119 Issues to be Scoped Out 119 14 Socio-Economics and Tourism 121 Introduction 121 Policy and Legislation 121 Baseline Environment 121 Potential Impacts 124 Dorset AONB: Visual Impact Provision 4 May 2016 Scoping Report Proposed Assessment Methodology 125 Proposed Mitigation Measures 128 Issues to be Scoped Out 128 15 Noise and Vibration 129 Introduction 129 Legislation and Policy 129 Baseline Environment 130 Part 1 - Construction and Decommissioning Noise and Vibration 130 Potential Impacts (Part 1) 130 Proposed Assessment Methodology (Part 1) 131 Proposed Mitigation Measures (Part 1) 132 Issues to be Scoped Out (Part 1) 132 Part 2 - Operational Noise 132 Introduction (Part 2) 132 Operational Noise and Vibration from Proposed New Infrastructure (Part 2) 132 Proposed Mitigation Measures (Part 2) 133 Issues to be Scoped Out (Part 2) 134 Part 3 - Summary and Conclusions 134 16 Climate Change 135 Introduction 135 Potential Impacts 135 Proposed Assessment Methodology 136 Proposed Mitigation Measures 136 Issues to be Scoped Out 136 17 Sustainability 137 18 Glossary / Abbreviations 139 19 References 151 Introduction References 151 Planning References 151 Landscape References 151 Ecology References 152 Archaeology and Cultural Heritage References 152 Water References 153 Geology, Soils and Contaminated Land References 154 Agriculture and Land Use 154 Air Quality References 154 Electric and Magnetic Fields References 155 Traffic and Transport References 155 Socio-Economics and Tourism References 155 Noise and Vibration References 156 Climate Change References 156 Sustainability References 156 Appendices 157 Appendix A: Preliminary Ecological Appraisal (PEA) Appendix B: Certificate of Conformity to the EC Directive 89/336 Dorset AONB: Visual Impact Provision 5 May 2016 Scoping Report This page has been left intentionally blank. Dorset AONB: Visual Impact Provision 6 May 2016 Scoping Report 1 Introduction Proposed Scheme Overview 1.1 National Grid is seeking a Scoping Opinion from West Dorset District Council to underground a section of the existing 4YA overhead line (OHL) (hereafter referred to as the ‘Visual Impact Provision (VIP) subsection’) within the Dorset Area of Outstanding Natural Beauty (AONB). 1.2 The undergrounding of the VIP subsection includes the following main elements that comprise the ‘proposed scheme’ (details are presented in Chapter 2): Construction of two new sealing end compounds (SECs) and associated replacement terminal pylons including permanent access, required to connect the new underground cables to the remaining existing OHL; Underground cabling of approximately 7km (depending on location of SECs and route of cable alignment); and Removal of the existing VIP subsection including approximately 18 pylons and 7km of OHL (depending on location of SEC). 1.3 This stakeholder driven proposed scheme forms part of the wider VIP project. Ofgem and National Grid have agreed a new set of price controls and incentives for the period from April 2013 to March 2021. This includes a provision of £500 million for electricity transmission owners to mitigate the visual impact of existing electricity infrastructure in nationally protected landscapes in Great Britain. For National Grid, which is the transmission owner in England and Wales, this means considering the effects of existing infrastructure on the visual amenity and landscapes of National Parks and AONBs. 1.4 Following the results of a landscape and visual impact assessment in 2014, covering all 571km of OHL within the scope of the VIP project, those sections of OHL which had the greatest visual impact on the surrounding landscape were identified. In September 2015, a Stakeholder Advisory Group (consisting of stakeholders with national remits for England and Wales) decided that four sections of OHL should be prioritised for detailed assessment. 1.5 The locations chosen are Dorset 4YA, New Forest 4YB, Peak District 4ZO and Snowdonia 4ZC. All sections were proposed as underground solutions, with Snowdonia having the potential for a cable tunnel if no direct bury option exists. VIP Subsection and Overview of Area 1.6 The existing 4YA route is part of the 400kV OHL route connecting Axminster, Chickerell and Exeter 400kV substations. The OHL was constructed between 1965 and 1969 and is of standard lattice pylon design with quad conductor bundles and has fibre optic wrapped earth wire. The location of the National Grid 4YA OHL and the VIP subsection in relation to the Dorset AONB boundary are shown in Figure 1.1. 1.7 The focus of the VIP project is on the mitigation of landscape and visual impacts, and the assessment of these impacts is set out in the landscape and visual impact assessment Technical Report (National Grid, 2014). The OHL in this area is judged to have: Dorset AONB: Visual Impact Provision 7 May 2016 Scoping Report landscape impacts of high importance particularly where it crosses through a small valley close to Winterbourne Abbas. This and other small valleys in the downland are more susceptible to the impacts of the OHL, while the open nature of the downland means that the impact extends across a large geographical area; visual impacts of high importance affecting users of the National Cycle Route and South Dorset Ridgeway, users of local footpaths and access land, and visitors to the landmark Hardy Monument. The OHL passes close to Winterbourne Abbas and is prominent above the settlement. Two steel pylon distributor OHLs flank the transmission OHL south of Winterbourne Abbas, and the smaller size of these pylons emphasise the height of the transmission pylons in views. There is a high scale of impact where the OHL crosses over the National Cycle Route. 1.8 The VIP subsection runs from a point north-west of Winterbourne Abbas, cutting across the A35 and south of Winterbourne Abbas in a south-easterly direction. It then turns slightly south, across the upper slopes of Corton Down on the South Dorset Escarpment, to lower ground south of Friar Waddon Hill. The VIP subsection is approximately 7km in length. 1.9 The ‘search area for permanent development’ (hereafter referred to as the ‘search area’) broadly follows the alignment of the VIP subsection as shown in the site identification drawing (see Figure 1.2). Based on current knowledge, this overall search area has been drawn sufficiently wide enough to take account of potential route alignment options, a preferred option which will be confirmed following further site visits, engineering and environmental studies and discussions with stakeholders. Dorset AONB: Visual Impact Provision 8 May 2016 Scoping Report Visual Impact Provision Project Dorset AONB 4YA OHL Search Area for Permanent Development Figure 1.2 Ordnance Survey data © Crown copyright and database right 2014 Legend 4YA Pylon Locations VIP Subsection 4YA Overhead Line Distribution Network Operator Overhead Line Search Area for Permanent Development Sealing End Compound Search Area Set up Scale size 1:15,000 A3 0 250 500 750 1,000 m Visual Impact Provision Project Dorset AONB