Level 1 Strategic Flood Risk Assessment (July 2017) Central Bedfordshire Strategic Flood Risk Assessment

CentralBedfordshireCouncil LocalPlan(2015-2035) Level 1 Strategic Flood Risk Assessment (July 2017) Central Bedfordshire Strategic Flood Risk Assessment Central Bedfordshire Strategic Flood Risk Assessment (SFRA) 1. Introduction 1.1 The National Planning Policy Framework (NPPF) requires that local planning authorities, when preparing Local Plans, should undertake a Strategic Flood Risk Assessment (SFRA). The SFRA appraises the risk of flooding in Central Bedfordshire. Flooding from all sources is considered (fluvial, groundwater, surface water and reservoirs). 1.2 All development proposals must consider existing and future flood risk, taking into account of climate change effects. This information will form the basis for preparing appropriate policies for flood risk management and assessing sites for development. Sites at low risk should normally be the preferred option. However, with suitable mitigation, essential development within high-risk areas can be achieved and the SFRA is designed to help inform CBC in these circumstances. 1.3 Central Bedfordshire’s SFRA is being prepared in two stages: The first stage (Level 1) comprises of a desk based study collating and reviewing existing and historic flooding information. The purpose of this first stage is to provide an assessment of the extent and nature of the risk of flooding in Central Bedfordshire and its implications for the Local Plan. This has been completed. A more detailed second stage SFRA (Level 2) will be undertaken once CBC has identified areas of new development in locations at flood risk. The purpose of this level of assessment is to assist the Council and developers to avoid inappropriate development in areas at risk of flooding, and to direct development away from areas at highest risk wherever possible, identifying suitable mitigation where this is unavoidable. This will be undertaken in autumn 2017. 1.4 The SFRA has been produced by the flood risk specialist consultant JBA. It has been developed using the best available information at the time of preparation. The SFRA should be updated regularly to reflect new information on flood risk, flood warning or new planning guidance or legislation. 2. Key Findings of Stage 1 2.1 Central Bedfordshire has been subject to flooding from several sources of flood risk, with the principal risk from fluvial sources (main rivers and ordinary watercourses). The main fluvial flood risk is located along the River Ivel corridor in the east, River Flit and River Hit in the centre and Clipstone Brook through Leighton Buzzard in the far west. The floodplain associated with the tributaries of the River Ivel network is generally broad due to the low-lying topography in this area. 2.2 As well as fluvial flooding, Central Bedfordshire has experienced a number of historic surface water/ drainage related flood events caused by a number of mechanisms, from insufficient storm / drainage capacity to poor surface water management. The Surface Water mapping shows a number of prominent overland flow routes, following topographical flow paths of existing watercourses or dry valleys and local road infrastructure with some isolated ponding located in low-lying areas. 2.3 There have been incidents of historic groundwater flooding in Central Bedfordshire which is thought to primarily be caused by the underlying geology of chalk and Lower Greensand which allow water to pass to and from groundwater aquifers. Central Bedfordshire Strategic Flood Risk Assessment 2.4 There are eight records of a canal overtopping along the Grand Union Canal since 2007. A high- level review of existing flood defences was undertaken and found few formal defences in the study area. 2.5 The SFRA is also required to show regard to the Water Framework Directive (WFD), which aims to protect water quality. Some of the watercourses in Central Bedfordshire already meet the ‘good’ overall ecological status including the Clipstone Brook, the River Ivel (upstream of Henlow) and the Ickwell Brook. However, the majority only meet ‘moderate’ overall status or less. 3. Summary of Implications 3.1 For sites being considered for growth that are within areas of high risk of flooding or that have watercourses flowing through or past them, the sequential approach should be used to locate development away from areas at highest risk. This approach will ensure the watercourses retain their connection to the floodplain, and will enhance the water environment and offers opportunities to use the land as green infrastructure/green corridors. 3.2 Developers need to ensure that new development does not increase the risk of surface water flooding from or to the site and ensure surface water management is undertaken to control run off. Sustainable drainage systems (SuDS) should be used on all new development, designed in response to site characteristics and policy factors. 3.3 Developments should demonstrate opportunities to create, enhance and link green assets. This can provide multiple benefits including flood risk and biodiversity/ ecology and may provide opportunities to use the land for an amenity and recreational purposes. Development that may adversely affect green infrastructure assets should not be permitted. 3.4 For successful future flood risk management, it is recommended that neighbouring planning authorities adopt a catchment partnership working approach in tackling flood risk and environmental management. 3.5 The Council needs to take positive measures to deliver the WFD and minimise ‘deterioration’ in ecological status of a watercourse as a result of new development. 3.6 Any developments located within an area protected by flood defences, where the condition of those defences is ‘fair’ or ‘poor’, and where the standard of protection is not of the required standard, consideration should be given to the use of developer contributions to fund improvements. Central Bedfordshire Strategic Flood Risk Assessment Appendix A Central Bedfordshire Strategic Flood Risk Assessment Level 1 Central Bedfordshire Council Level 1 Strategic Flood Risk Assessment Draft Report May 2017 Central Bedfordshire Council Priory House Monks Walk CHICKSANDS Bedfordshire SG17 5TQ This page is intentionally left blank. 2016s4180 Central Bedfordshire Draft Level 1 SFRA v5.0.docx JBA Project Manager Joanne Chillingworth The Library St Philip’s Courtyard Church End COLESHILL B46 3AD Revision History Revision Ref / Date Amendments Issued to Issued Draft Report v1.0 / Pru Khimasia-John, Central Bedfordshire July 2016 Council Draft Report v2.0 / Addressed first Pru Khimasia-John, Central Bedfordshire December 2016 draft comments Council Draft Report v3.0 / Addressed Pru Khimasia-John, Central Bedfordshire December 2016 second draft Council comments from CBC and EA Draft Report v4.0 / Minor Pru Khimasia-John, Central Bedfordshire May 2017 amendments to Council cover and appendix titles Draft Report v5.0 / Minor Pru Khimasia-John, Central Bedfordshire May 2017 amendments to Council Section 2.3.1 Contract This report describes work commissioned by Central Bedfordshire Council. The Council’s representative for the contract was Pru Khimasia-John. Prepared by .................................................. Joanne Chillingworth BSc MSc MCIWEM C.WEM Chartered Senior Analyst Freyja Scarborough BSc MSc Assistant Analyst Reviewed by ................................................. Claire Gardner BSc MSc MCIWEM C.WEM Chartered Senior Analyst Purpose This document has been prepared as a Draft Report for Central Bedfordshire Council. JBA Consulting accepts no responsibility or liability for any use that is made of this document other than by the Client for the purposes for which it was originally commissioned and prepared. JBA Consulting has no liability regarding the use of this report except to Central Bedfordshire Council. 2016s4180 Central Bedfordshire Draft Level 1 SFRA v5.0.docx Acknowledgements We would like to acknowledge the assistance of: • Central Bedfordshire Council, including Highways • Environment Agency • Anglian Water • Thames Water • Affinity Water • Canal and River Trust • Forest of Marston Vale • Bedford Group of Internal Drainage Boards; and • Planners at the neighbouring authorities Copyright © Jeremy Benn Associates Limited 2017 Carbon Footprint A printed copy of the main text in this document will result in a carbon footprint of 652g if 100% post-consumer recycled paper is used and 829g if primary-source paper is used. These figures assume the report is printed in black and white on A4 paper and in duplex. JBA is aiming to reduce its per capita carbon emissions. 2016s4180 Central Bedfordshire Draft Level 1 SFRA v5.0.docx Executive Summary Introduction JBA Consulting were commissioned by Central Bedfordshire Council to prepare an updated Strategic Flood Risk Assessment (SFRA). The purpose of this study is to provide a comprehensive and robust evidence base to support the production of the Local Plan to 2036 and will replace the existing Strategic Flood Risk Assessments for Mid- and South Bedfordshire (both published in 2008). The 2016 SFRA update will be used in decision-making and to inform decisions on the location of future development and the preparation of sustainable policies for the long-term management of flood risk. SFRA objectives The key objectives of the 2016 Strategic Flood Risk Assessment are: • To provide a tool for assessing flood risk from various sources of current and future flooding and how these may be mitigated. • To identify the likely effects of climate change on flood risk. •

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