The Pest House, Claygate Road, Yalding
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THE PEST HOUSE, CLAYGATE ROAD, YALDING FLOOD RISK ASSESSMENT LEVEL 2 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 CONTROL SHEET CLIENT: LADDINGFORD DEVELOPMENTS LTD PROJECT TITLE: THE PEST HOUSE, CLAYGATE ROAD, YALDING REPORT TITLE: FLOOD RISK ASSESSMENT – LEVEL 2 PROJECT REFERENCE: LN35-PH Issue and Approval Schedule: 1st Issue Name Signature Date Draft Prepared by Lance Greenaway 30.08.2018 Reviewed by Ray Pearson 30.08.2018 Approved by Ciaran Downey 30.08.2018 Rev. Date Status Description Signature By Checked Approved By Revision Record Checked Approved Dandara Ltd Eridge House, 1 Linden Close Tunbridge Wells, Kent, TN4 8HH Tel: 01892 800802 2 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 CONTENTS 1 EXECUTIVE SUMMARY ................................................................................................................. 4 2 INTRODUCTION............................................................................................................................ 5 3 PLANNING POLICY........................................................................................................................ 6 4 DEVELOPMENT DESCRIPTION AND LOCATION .......................................................................... 10 5 DEFINITION OF FLOOD HAZARD ................................................................................................ 12 6 PROBABILITY OF FLOODING ...................................................................................................... 13 7 KCC SUSTAINABLE DRAINAGE SYSTEMS POLICY ........................................................................ 14 8 DEVELOPMENT PROPOSAL ........................................................................................................ 18 9 FLOOD RISK MITIGATION MEASURES ........................................................................................ 20 10 CONCLUSIONS ............................................................................................................................ 21 11 REFERENCES ............................................................................................................................... 22 APPENDICIES APPENDIX A – SITE LOCATION PLAN APPENDIX B – GREENFIELD RUNOFF CALCULATIONS APPENDIX C – BROWNFIELD RUNOFF CALCULATIONS APPENDIX D – PROPOSED DRAINAGE STRATEGY APPENDIX E – PROPOSED SURFACE WATER CALCULATIONS APPENDIX F – ENVIRONMENT AGENCY PRODUCT 4 FIGURES Figure 1: EA/NRW – Flood Data Map ..................................................................................................... 5 Figure 2: KCC SuDS Policy Summary .................................................................................................... 8 3 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 1 EXECUTIVE SUMMARY This Flood Risk Assessment (FRA) has been prepared on behalf of Laddingford Developments Ltd, to accompany a planning application submitted to the Maidstone Borough Council for the refurbishment of The Pest House, Claygate Road, Yalding, ME18 6BB The Pest House is a Grade II listed timber-framed dwelling dating from the 16 th Century. According to t he Environment Agency’s indicative flood map s, the site is located in Flood Zone 2, which has between 1% & 0.1% annual probability of fluvial flooding (Between 1 in 100 & 1 in 1000-year return period). The overall site area is less than 1 hectare (ha). The site location plan is shown in Appendix A. This FRA will set out the existing limitations and proposed options relating to the discharge of surface water runoff generated by the proposed development. This report will outline various methods of providing appropriate sustainable solutions to enhance the local environment and improve current downstream conditions, whilst allowing for proposed usage and possible future climate change effects. The Pest House has existing drainage connection to the adjacent Bentlett’s Yard site. The former scrapyard is currently being redeveloped and the Pest House drainage connections are being retained and included in the overall drainage scheme. This allows the Pest House to benefit from the main attenuation and SuDS scheme. 4 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 2 INTRODUCTION Dandara Ltd has been commissioned by Laddingford Developments Ltd to undertake a Level 2 Flood Risk Assessment (FRA) to accompany a planning application submitted to Maidstone Borough Council for the refurbishment of The Pest House, Claygate Road, Yalding, ME18 6BB. Following a review of the SFRA report and current information from the Environment Agency flood data maps (Figure 1), the site is noted to be located in a Flood Zone 2 area which is categorised as having a medium-low risk of flooding. Figure 1: EA/NRW – Flood Data Map This FRA has been compiled in accordance with the SFRA, KCC Drainage & Planning Policy and the National Planning Policy Framework (NPPF). 5 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 3 PLANNING POLICY 3.1 National Planning Policy Framework & Planning Practice Guidance 3.1.1 The National Planning Policy Framework (NPPF) and the associated Technical Guidance, published/revised in 2012, 2014 and 2018 respectively, identify flood risk as a specific material consideration in the planning process and in the allocation and release of sites for development or re-development. 3.1.2 The NPPF & Technical Guidance replaced previous guidance and policy set out in PPS 25: Development and Flood Risk, however much of the technical criteria for Flood Risk Assessments remain largely unchanged. The NPPF seeks to strengthen the co-ordination between land-use planning and development planning and the operational delivery of flood and coastal defence strategy. Through the NPPF, Local Planning Authorities will continue to use their existing powers to guide, regulate and control development in relation to flooding and flood risk. The NPPF places a presumption in favour of sustainable development whilst meeting the challenge of climate change, flooding and coastal change. In accordance with the PPG, inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk through the application of the Exception and Sequential Tests. 3.1.3 The Water Resources Act 1991 [Section 105] requires the Environment Agency to exercise general supervision over all flood defence matters, including flood plains and washlands, which accommodate waters during periods of flood. In discharging their functions, the Environment Agency from time to time carries out surveys and flood studies, largely of ‘main rivers’ within its jurisdiction. 3.1.4 Environment Agency flood maps indicating the extents of the modelled floodplain are provided to Local Planning Authorities, to enable them to make more informed decisions when considering proposed development in flood-susceptible areas. If development is proposed in a flood-susceptible area, or in an area where there is a history of flooding, the Environment Agency, as a statutory consultee in the planning process, will generally recommend that the risk of flooding be formally assessed in accordance with the NPPF, and that a Flood Risk Assessment report is produced to support the Planning Application. The broader modelled flood extents are also 6 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 indicated on the Environment Agency’s Flood Zone Maps, available through their website. 3.2 Strategic Flood Risk Assessment (SFRA) 3.3 A SFRA has been prepared by Mott MacDonald and Maidstone Borough Council and is dated May 2008. This shows that the site lies with Flood Zone 1 and is at a low risk of flooding. However, recently updated flood mapping from the EA now shows the site in Flood Zone 2. 3.3 Sequential Test 3.3.1 The Sequential Approach is detailed within the NPPF Technical Guidance and aims to ensure preference is given to land within Flood Zone 1 prior to Zones 2 and 3. It also ensures that flood vulnerability of the Proposed Development is taken into consideration when locating development in Flood Zones 2 and 3. 3.3.2 Where the Sequential Approach shows that it is not possible to locate development in zones of lower flood risk due to other wider sustainability issues; it may be possible to justify, using the Exception test, that development is still feasible by the management of flood risk. 3.3.3 Table 3 of the NPPF Technical Guidance defines when the Exception Test is applicable. The Technical Guidance states that sites at lower risk (i.e. Flood Zone 1) should be developed in preference to sites at higher risk (Flood Zone 2), and that ‘ only where there are no reasonably available sites in Flood Zones 1 and 2 should the suitability of sites in Flood Zone 3 be considered .’ 3.4 Kent County Council Drainage & Planning Policy 3.4.1 Kent County Council (KCC) issued their current Drainage and Planning Policy in July 2017. 3.4.2 KCC provides a list of ten Sustainable Drainage Systems (SuDS) Policies (Figure 2) which are to be complied with for all developments: 7 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 Figure 2: KCC SuDS Policy Summary 3.4.3 These policies are reviewed later in this document. 8 August 2018 The Pest House, Claygate Road, Yalding Flood Risk Assessment – Level 2 CIRIA Guidance 3.4.4 CIRIA publication ‘C624 Development and Flood Risk – Guidance