Norfolk Boreas Offshore Wind Farm Chapter 10 Benthic and Intertidal Ecology
Total Page:16
File Type:pdf, Size:1020Kb
Norfolk Boreas Offshore Wind Farm Chapter 10 Benthic and Intertidal Ecology Environmental Statement Volume 1 Applicant: Norfolk Boreas Limited Document Reference: 6.1.10 RHDHV Reference: PB5640-006-010 Pursuant to APFP Regulation: 5(2)(a) Date: June 2019 Revision: Version 1 Author: Royal HaskoningDHV Photo: Ormonde Offshore Wind Farm Date Issue Remarks / Reason for Issue Author Checked Approved No. 27/02/2019 01D First draft for Norfolk Boreas Limited review ES DT/ KW AD 23/03/2019 02D Second draft for Norfolk Boreas Limited review ES DT/JL/CR PP 10/04/2019 01F Final for DCO submission ES DT JL Environmental Statement Norfolk Boreas Offshore Wind Farm 6.1.10 June 2019 Page i Table of Contents 10 Benthic and Intertidal Ecology ................................................................................. 1 10.1 Introduction ........................................................................................................... 1 10.2 Legislation, Guidance and Policy ............................................................................. 2 10.3 Consultation ........................................................................................................... 5 10.4 Assessment Methodology ..................................................................................... 16 10.5 Scope ................................................................................................................... 20 10.6 Existing Environment ............................................................................................ 25 10.7 Potential Impacts.................................................................................................. 38 10.8 Cumulative Impacts ............................................................................................ 102 10.9 Inter-relationships .............................................................................................. 108 10.10 Interactions ........................................................................................................ 109 10.11 Summary ............................................................................................................ 110 10.12 References ......................................................................................................... 113 Environmental Statement Norfolk Boreas Offshore Wind Farm 6.1.10 June 2019 Page ii Tables Table 10.1 NPS Assessment Requirements 2 Table 10.2 Consultation Responses 6 Table 10.3 Definitions of Sensitivity Levels for Benthic and Intertidal Ecology 17 Table 10.4 Definitions of Value Levels for Benthic and Intertidal Ecology 17 Table 10.5 Definitions of Magnitude Levels for Benthic and Intertidal Ecology 18 Table 10.6 Impact Significance Matrix 18 Table 10.7 Impact Significance Definitions 19 Table 10.8 Data Sources 22 Table 10.9 Indicative Norfolk Boreas construction programme – single phase 46 Table 10.10 Indicative Norfolk Boreas construction programme – two phases 47 Table 10.11 Parameters for pre-sweeping activity for the offshore export cable corridor and project interconnector search area. 50 Table 10.12 Worst Case Scenarios 56 Table 10.13 Sensitivities of biotopes within the offshore cable corridor to physical disturbance (source: Tyler-Walters, Lear and Allen, 2004; Tillin, 2014b; Tillin, 2016) 71 Table 10.14 Sensitivities of biotopes within the project interconnector search area to physical disturbance (source: Tyler-Walters, Lear and Allen, 2004; Tillin, 2014b; Tillin, 2016, Tillin 2016b) 74 Table 10.15 Sensitivities of receptors within the Norfolk Boreas site to increased suspended sediment and smothering by deposited sediment (source: Tyler-Walters 2004, Lear and Allen, 2004; Tillin et al., 2015; Jackson & Hiscock, 2008; Ager, 2005) 78 Table 10.16 Sensitivities of receptors within the offshore cable corridor to increased suspended sediment and smothering by deposited sediment (source: Tillin, 2016; Tillin & Marshall, 2015; Tillin, 2016c) 82 Table 10.17 Sensitivity of biotopes with the Norfolk Boreas site to habitat change to hard or artificial habitat. (source: Tyler-Walters, Lear and Allen, 2004; Tillin, 2014b; Tillin, 2016) 96 Table 10.18 Potential cumulative impacts 102 Table 10.19 Summary of Projects considered for the CIA in Relation to the Topic 107 Table 10.20 Benthic and Intertidal Ecology inter-relationships 108 Table 10.21 Interaction between impacts 109 Table 10.22 Potential impacts identified for benthic and intertidal ecology 110 Plates Plate 10.1 Export cables layout (two pairs of cables for Norfolk Boreas (blue) and two pairs of cables for Norfolk Vanguard (yellow)) based on 48m water depth .................................... 41 Environmental Statement Norfolk Boreas Offshore Wind Farm 6.1.10 June 2019 Page iii Figures (Volume 2) Figure 10.1 Benthic survey locations Figure 10.2 Sediment distribution Figure 10.3 Infaunal abundance Figure 10.4 Infaunal diversity Figure 10.5 Infaunal biomass Figure 10.6 Infaunal groups Figure 10.7 Epifaunal abundance Figure 10.8 Epifaunal diversity Figure 10.9 Epifaunal groups Figure 10.10 Biotope map Figure 10.11 Sabellaria spinulosa abundance Figure 10.12 Sabellaria spinulosa reef Figure 10.13 Designated sites Appendices (Volume 3) Appendix 10.1 Benthic Characterisation Report Appendix 10.2 Benthic Ecology Data Analysis Appendix 10.3 Comparison of MarLIN and Norfolk Boreas sensitivity definitions for benthic receptors Environmental Statement Norfolk Boreas Offshore Wind Farm 6.1.10 June 2019 Page iv Glossary of Acronyms ANOSIM Analysis of Similarities BAP Biodiversity Action Plan CEMP Construction Environmental Management Plan CIA Cumulative Impact Assessment CIEEM Chartered Institute of Ecology and Environmental Management DCO Development Consent Order EAOW East Anglia Offshore Wind EC European Commission EMF Electromagnetic Fields EMODnet European Marine Observation and Data Network EIA Environmental Impact Assessment EIFCA Eastern Inshore Fisheries Conservation Authority EPP Evidence Plan Process ES Environmental Statement ETG Expert Topic Group FEPA Food and Environment Protection Agency FERA Food and Environment Research Agency GBS Gravity Based Structure HDD Horizontal Directional Drilling HPI Habitats of Principal Importance HRA Habitats Regulations Assessment HVDC High Voltage Direct Current IEEM Institute of Ecology and Environmental Management IPC Infrastructure Planning Commission (now the Planning Inspectorate) JNCC Joint Nature Conservation Committee LAT Lowest Astronomical Tide MarLIN Marine Life Information Network MarESA Marine Evidence Based Sensitivity Assessment MARPOL International Convention for the Prevention of Pollution from Ships MCZ Marine Conservation Zone MESL Marine Ecological Surveys Limited MHWS Mean High Water Spring MLWS Mean Low Water Springs MMO Marine Management Organisation MPS Marine Policy Statement NBN National Biodiversity Network NPL National Physical Laboratory NE Natural England NPS National Policy Statement NSIP Nationally Significant Infrastructure Project NV East Norfolk Vanguard East NV West Norfolk Vanguard West ODPM Office of the Deputy Prime Minister O&M Operation and Maintenance Environmental Statement Norfolk Boreas Offshore Wind Farm 6.1.10 June 2019 Page v OWF Offshore Wind Farm PEIR Preliminary Environmental Information Report REC Regional Environmental Characterisation RSBL Reference Seabed Level SAC Special Area of Conservation SIP Site Integrity Plan SMRU Sea Mammal Research Unit SNCB Statutory Nature Conservation Body SPA Special Protection Area SPI Species of Principal Importance SSC Suspended Sediment Concentrations UXO Unexploded Ordnance VWPL Vattenfall Wind Power Limited WT Wildlife Trust WCS Worst Case Scenario ZEA Zonal Environmental Appraisal Glossary of Terminology Array cables Cables which link the wind turbine to wind turbine and wind turbine to offshore electrical platform. Evidence Plan Process A voluntary consultation process with specialist stakeholders to agree the approach to the EIA and information to support HRA. Interconnector cables Offshore cables which link offshore electrical platforms within the Norfolk Boreas site Landfall Where the offshore cables come ashore at Happisburgh South Landfall compound Compound at landfall within which HDD drilling would take place. Norfolk Boreas The Norfolk Boreas wind farm boundary. Located offshore, this will contain all the wind farm array. Offshore cable corridor The corridor of seabed from the Norfolk Boreas site to the landfall site within which the offshore export cables will be located. Offshore electrical platform A fixed structure located within the Norfolk Boreas site, containing electrical equipment to aggregate the power from the wind turbines and convert it into a suitable form for export to shore. Offshore export cables The cables which bring electricity from the offshore electrical platform to the landfall. Offshore project area The area including the Norfolk Boreas site, project interconnector search area and offshore cable corridor. Offshore service platform A fixed structure providing accommodation for offshore personnel and /or helicopter refuelling facilities. An accommodation vessel may be used instead Project interconnector Offshore cables which would link either turbines or an offshore electrical cable platform in the Norfolk Boreas site with an offshore electrical platform in one of the Norfolk Vanguard sites. Project interconnector The area within which the project interconnector cable would be installed. search area Scour protection Protective materials