Bulphan Fen Solar Farm and Battery Storage Flood Risk Assessment on Behalf of Warley Green Limited
Total Page:16
File Type:pdf, Size:1020Kb
Bulphan Fen Solar Farm and Battery Storage Flood Risk Assessment on behalf of Warley Green Limited Prepared by RMA Environmental | December 2020 | Document Reference: R010 FLOOD RISK ASSESSMENT AND DRAINAGE STRATEGY Proposed Solar Farm and Battery Storage Land at Harrow Lane Bulphan Thurrock RM14 3RE Prepared for: Warley Green Limited 7th January 2021 Project Number: RMA-C2095 THIS PAGE HAS BEEN LEFT BLANK INTENTIONALLY RMA Environmental Limited, 1 Emperor Way, Exeter Business Park, Exeter, EX1 3QS t 01392 576227 e [email protected] w www.rma-environmental.co.uk Registered in England No. 6915388. Registered Office: 2 Chartfield House, Castle Street, Taunton TA1 4AS Warley Green Limited Bulphan Solar Farm and Battery Storage FRA Document Production Record: Report Number: RMA-RC2095 Prepared by: Rosie Tutton Checked by: Nick Yeo Approved by: Rob Murdock Document Revision Record: Issue Number Date Revision Details 1 19th November 2020 Client Issue 2 21st December 2020 Final 3 7th January 2021 Revised Final RMA Environmental Limited has prepared this report in accordance with the instructions of the above named client for their sole and specific use. Any third parties who may use the information contained herein do so at their own risk. Issue 3 i RMA Environmental January 2021 RMA-C2095 Warley Green Limited Bulphan Solar Farm and Battery Storage FRA CONTENTS 1 INTRODUCTION ......................................................................................................... 1 Background ............................................................................................................................ 1 Site Location And Land Use................................................................................................... 1 Proposed Development .......................................................................................................... 2 Requirements For A Flood Risk Assessment ........................................................................ 2 Consultation ........................................................................................................................... 3 2 BASELINE ENVIRONMENTAL CONDITIONS ............................................................ 4 Topography ............................................................................................................................ 4 Hydrology ............................................................................................................................... 5 Geology And Hydrogeology ................................................................................................... 5 3 EXTERNAL FLOOD RISK ........................................................................................... 7 Flooding Mechanisms ............................................................................................................ 7 Historic Flooding..................................................................................................................... 7 Fluvial Flood Risk ................................................................................................................... 7 Tidal Flood Risk ...................................................................................................................... 9 Surface Water Flood Risk .................................................................................................... 10 Groundwater Flood Risk ...................................................................................................... 11 Reservoir Flood Risk ............................................................................................................ 11 Mitigation Measures ............................................................................................................. 11 Safe Access/Egress ............................................................................................................. 13 Land Use Vulnerability ......................................................................................................... 13 Other Considerations ........................................................................................................... 14 4 DRAINAGE ASSESSMENT ...................................................................................... 15 Introduction ........................................................................................................................... 15 Drainage Strategy ................................................................................................................ 15 5 CONCLUSIONS ........................................................................................................ 19 FIGURES Figure 1.1: Site Location Plan Figure 2.1: Watercourse Plan Figure 3.1: EA’s Flood Map for Planning Figure 3.2: EA’s Surface Water Flood Map Figure 3.3: EA’s Reservoir Flood Depth Map Figure 3.4a/b: Estimated Flood Depths during the 0.1% AEP Event Figure 3.5: EA’s Low Surface Water Flood Risk Depths APPENDICES Appendix A: Field Number Plan Appendix B: Solar Panel Framework - Flood Stow System Appendix C: EA Consultation Appendix D: Topographical Survey Issue 3 ii RMA Environmental January 2021 RMA-C2095 Warley Green Limited Bulphan Solar Farm and Battery Storage FRA Appendix E: EA Flood Data Appendix F: SFRA Breach Modelling Issue 3 iii RMA Environmental January 2021 RMA-C2095 Warley Green Limited Bulphan Solar Farm and Battery Storage FRA 1 INTRODUCTION Background 1.1 RMA Environmental Limited was commissioned by Aardvark EM Limited on behalf of Warley Green Limited to prepare a Flood Risk Assessment (FRA) to support a full planning application for a proposed solar farm and battery storage facility (“the Proposed Development”) on land at Harrow Lane near Bulphan, Thurrock, RM14 3RE (“the Site”). 1.2 This FRA has been prepared in accordance with the National Planning Policy Framework (NPPF), associated Planning Practice Guidance (PPG) and Environment Agency (EA) standing advice on flood risk for new development. Site Location and Land Use 1.3 The Site comprises greenfield land which is currently in agricultural use; it extends to an area of approximately 142.6 hectares (ha) and is located at National Grid Reference TQ 62579 84583 (refer to Figure 1.1). The fields within the Site are referred to as Fields 1 to 18 for the purpose of this assessment (refer to Appendix A). 1.4 The Site is bordered by the following land-uses: • agricultural land surrounds the majority of the Site; • Fen Lane is located to the north of the Site; • Fen Farm is located to the north-west of the Site; • Harrow Road, Harrow Lane and a number of farms are located along the northern boundary of the Site; • Church Lane and Parker’s Farm Road are located to the east of the Site; • the urban area of Bulphan is located to the east of the Site; and • a track is located to the south-east of the Site. 1.5 Access to the Site is currently via Fen Lane to the north-west, Harrow Lane along the northern boundary and an existing track leading to Fen Lane to the north-east of the Site. Further details on Site topography, geology and hydrology are set out in Section 2. Issue 3 1 RMA Environmental January 2021 RMA-C2095 Warley Green Limited Bulphan Solar Farm and Battery Storage FRA Proposed Development 1.6 The Proposed Development comprises the construction, operation, management and decommissioning of a grid connected solar farm with battery storage and associated infrastructure (“the generating station”). The generating station would supply up to 49.9 MW of clean renewable electricity to the National Grid for c. 35 years from the date of first exportation of electricity from the Site. The battery storage facility would be utilised to reinforce the power generation of the solar farm, storing energy at times of low demand and releasing to the grid in periods of higher demand or when solar irradiance is lower, as well as providing balancing services to maintain National Grid stability. The Proposed Site Layout is contained within the Planning Application Drawing Pack (Drawing No: BF2.0) accompanying the application. 1.7 The planning application seeks full planning permission for the following Description of Development (“the Proposed Development”): “Installation of renewable led energy generating station comprising ground- mounted photovoltaic solar arrays and battery-based electricity storage containers together with substation, inverter/transformer stations, site accesses, internal access tracks, security measures, access gates, other ancillary infrastructure, landscaping and biodiversity enhancements.” 1.8 The metal framework that supports the solar panels would be fixed into the ground by posts, which would be pile-driven to a depth of around 2 m to 2.5 m (i.e. no concrete foundations). Solar panels would be laid out in rows with gaps of approximately 2-6m between each row depending on the topography of particular fields. 1.9 Solar panels will be mounted on framework which incorporates a tracking system, whereby the panels track the sun from east to west (Appendix B). The framework system includes a flood stow setting which elevations the panels in a higher horizontal position during flood events. 1.10 The Site would be accessed via the existing access points. These access routes would be used during both the construction and operational phases. Requirements for a Flood Risk Assessment 1.11 The requirements for FRA are provided in the NPPF and associated PPG. Paragraph 163 of the NPPF