Coventry City Council Level 1 and 2 Strategic Flood Risk Assessment Final Draft Report December 2015 Coventry City Council Earl Street COVENTRY CV1 5RR This page is intentionally left blank 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc JBA Project Manager Claire Gardner The Library St Philip’s Courtyard Church End COLESHILL B46 3AD Revision History Revision Ref / Amendments Issued to Date Issued Rob Haigh (Coventry City Council) Draft v1.0 Neal Thomas (Coventry City Council) (Sept 2015) Martin Ross (Environment Agency) Amendments to text Rob Haigh (Coventry City Council) Final Draft v1.0 based on review Neal Thomas (Coventry City Council) (Nov 2015) comments Martin Ross (Environment Agency) Contract This report describes work commissioned by Coventry City Council. The Council’s representative for the contract was Rob Haigh. Prepared by .................................................. Andrew Waite BSc MRes Analyst ....................................................................... Claire Gardner BSc MSc MCIWEM C.WEM Chartered Senior Analyst Reviewed by ................................................. Alastair Dale BSc PGDip MIAHR Director 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc Purpose This document has been prepared as a Draft Report for Coventry City 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 Coventry City Council. 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc Acknowledgements We would like to acknowledge the assistance of Coventry City Council, the Environment Agency, Severn Trent Water, Canal and River Trust, Coventry, Solihull and Warwickshire Resilience Team and planners at the neighbouring authorities of Nuneaton and Bedworth Borough, Rugby Borough, Warwick District, North Warwickshire Borough and Solihull Metropolitan Council. Copyright © Jeremy Benn Associates Limited 2015 Carbon Footprint A printed copy of the main text in this document will result in a carbon footprint of 643g if 100% post-consumer recycled paper is used and 819g 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. 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc This page is intentionally left blank 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc Executive Summary Introduction This Strategic Flood Risk Assessment (SFRA) 2015 document replaces the Level 1 SFRA originally published by Coventry City Council in July 2008. This report also includes a Level 2 SFRA of possible development locations identified for potential allocation within the Local Plan. The report has been prepared to replace the content included in the previous version of the SFRA and to provide appropriate supporting evidence for the emerging Local Plan. SFRA objectives The Planning Practice Guidance advocates a tiered approach to risk assessment and identifies the following two levels of SFRA: 1. Level One: where flooding is not a major issue in relation to Strategic Housing Land Availability Assessment (SHLAA) sites and where development pressures are low. The assessment should be sufficiently detailed to allow application of the Sequential Test. 2. Level Two: where land outside Flood Zones 2 and 3 cannot appropriately accommodate all the necessary development creating the need to apply the NPPF’s Exception Test. In these circumstances the assessment should consider the detailed nature of the flood characteristics within a Flood Zone and assessment of other sources of flooding. The objectives of this SFRA update are a hybrid of Level One and Level Two and seek to: provide an updated SFRA (changes to legislation, recent guidance, improved knowledge on flood risk); provide a framework for future flood risk analysis through a Level 2 SFRA for potential development locations identified by Coventry City Council; and provide a framework for the performance of the Sequential Testing of sites and, where necessary, the consideration of the Exception Test. The following outputs have been prepared to meet the objectives: SFRA outputs Level one outputs Appraisal of all potential sources of flooding, including Main River, Ordinary Watercourse, surface water and groundwater. Review of historical flooding incidents. Mapping of location and extent of functional floodplain. Reporting on the standard of protection provided by existing flood risk management infrastructure. An assessment of the potential increase in flood risk due to climate change. Areas at risk from other sources of flooding, for example surface water or reservoirs. An assessment of the impact of future large-scale developments both within and outside .Coventry An assessment of existing flood warning and emergency planning procedures, including assessment of safe access and egress during an extreme event. Recommendations of the criteria that should be used to assess future development proposals and the development of a Sequential Test and sequential approach to flood risk. High level screening of proposed development sites against flood risk information. 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc i Level two outputs The content of the Level Two SFRA includes detailed assessments of potential development sites identified during the Level 1 assessment. These include: an assessment of all sources of flooding including o fluvial flooding, including depth velocity and hazard mapping; o definition and mapping of the functional floodplain; o potential increase in flood risk due to climate change; o surface water flooding; and o groundwater flooding. advice and recommendations on the likely applicability of sustainable drainage systems for managing surface water runoff; advice on safe access and egress; advice on potential strategic solutions to flood risk; advice on appropriate policies for sites which could satisfy the first part of the Exception Test and on the requirements that would be necessary for a site-specific Flood Risk Assessment supporting a planning application to pass the second part of the Exception Test; and consideration of interrelated issues including. o water quality, ecology and green space; and o opportunities to restore the natural floodplain. Summary of Level 1 Assessment The SFRA has considered all sources of flooding including fluvial, surface water, groundwater, sewers and reservoir within the study area. There are a number of regional policy considerations relating to flood risk management in Coventry City, including Coventry City Council’s draft SWMP and LFRMS. Coventry City Council are also preparing a Water Cycle Study. The Sequential approach to development and flood risk has been defined with guidance provided for the application of the Sequential and Exception Tests for both the Local Plan and for detailed, site specific flood risk assessments. Strategic flood risk solutions have been considered for Coventry, such as the construction of new upstream storage schemes on a number of watercourses, re- naturalisation, considering SuDS at an early stage in the development of a site, and engaging stakeholders to work together to identify issues and provide suitable solutions. Emergency planning considerations have been included and the flood warning service coverage assessed; currently there are two Flood Alert Areas and eight Flood Warning Areas (FWAs) covering significant parts of Coventry. Requirements for safe access and egress have also been set out. When necessary development and redevelopment within the City Council administrative area shall require a flood risk assessment (FRA) appropriate to the scale of the development and to the scope agreed with the LLFA. The FRA must be produced to the current national and local standards and include information on all current and future flood risk. These documents should utilise the SWMP, PFRA, FRMP and SFRA for Coventry City as sources of information. FRAs should consider flood risk from all sources including residual risk, along with promotion of SuDS to create a conceptual drainage strategy and safe access/egress at the development in the event of a flood. Guidance on flood risk assessments and surface water management has been provided. Site-specific FRAs should include assessment of mitigation measures required to safely manage flood risk along with the along with promotion of SuDS to create a conceptual drainage strategy and safe access/ egress at the development in the event of a flood. 2015s2886 Coventry SFRA Final Draft Report (Dec 15).doc ii The LLFA set out a number of conditions which should be implemented within new or re- developments. The potential development sites within the study area were screened to identify sites where additional modelling would be required as part of the Level 2 assessment, for example, sites where there is a watercourse that is not included in the Environment Agency’s Flood Zone coverage, or where Flood Zones exist but further modelling was required to identify Flood Zone 3b and climate change as well as depth, velocity and hazard information. New 1D-2D hydraulic models were commissioned as part of this study to understand flood risk at these sites. On completion of the modelling, the sites were screened again to provide a summary of risk to each site including: