Reducing Flood Risk

re. Policy ID.9 Reducing Flood Risk A. Reducing Flood Risk Development proposals should be prioritised to areas of lowest flood risk and must not increase flood risk elsewhere, taking account of climate change over the lifetime of the development. Proposals must: 1. apply a sequential approach to site selection, layout and design, considering flood risk from all sources, including fluvial, surface water, groundwater and sewer flooding, informed by the latest Strategic Flood Risk Assessment (SFRA), national and local flood risk mapping, and available historic flood information; 2. demonstrate, through proportionate evidence, that flood risk will be managed safely within the site and will not increase flood risk to surrounding or downstream areas; and 3. incorporate flood risk management measures from the earliest stages of site design. B. Flood Risk Assessment A site-specific Flood Risk Assessment (FRA) will be required for development, in accordance with national policy and guidance. Where the development includes existing watercourses, the risk of river flooding must be fully appraised. Where existing flood risk information or modelling is absent or of insufficient quality, proportionate hydraulic modelling may be required to fully assess flood risk. Submitted FRAs should have regard to the recommendations of the latest SFRA and Warwickshire County Council’s Local Flood Risk Management Strategy. Development proposals must account for climate change, including exceedance events and the potential failure of infrastructure. Layouts must ensure that overland flow routes are safely managed through the site and do not place people or property at increased risk. C. Drainage Strategy All development must be supported by a drainage strategy demonstrating that surface water will be managed in line with the drainage hierarchy and that flood risk will not be increased to surrounding or downstream areas D. Sites at Risk of Flooding Within sites at risk of flooding: 1. buildings and access routes must be located in areas of lowest flood risk; 2. safe access and egress must be demonstrated; 3. finished floor levels must be set at least 600mm above the 1% annual probability plus climate change flood level; and 4. mitigation must be provided for any residual flood risk. Where land re-profiling or compensation works are proposed within areas at flood risk, these must be necessary to manage flood risk and should not be used to increase the developable area of the site. Proposals should be supported by post- development hydraulic modelling to demonstrate they do not increase flood risk. Detailed consideration must be given to exceedance and overland flow routes where ground levels are altered. E. Green and Blue Infrastructure Development will be required to create space for water through the use of green and blue infrastructure, including, where appropriate, restoring or reconnecting functional floodplains (Flood Zone 3b) and opportunities for river restoration and enhancement. Development that promotes upstream or downstream nature-based solutions will be considered where evidenced they deliver policy requirements and can be secured in perpetuity. An undeveloped buffer of at least 8 metres must be provided along watercourses, measured from the top of the bank or the centreline of a culvert, to allow for maintenance, flood conveyance, and ecological enhancement. F . Managing Flood Risk Development must not prejudice the operation of existing or planned flood risk management schemes. Land required for current and future flood management purposes will be safeguarded from development. In terms of the risks to traditional buildings from flooding, care must be taken not to introduce inappropriate retrofitted measures which would prevent effective drying and shorten the life of the building. Policy Justification 3.4.2 South Warwickshire has a history of flooding from multiple sources, and climate change is expected to increase both the frequency and severity of flood events. In addition to these existing risks, recent canal failures, including the Bridgewater Canal & Llangollen Canal, have highlighted a residual risk of flooding from canals. Where relevant, this additional risk should be considered within a Flood Risk Assessment. 3.4.3 This policy ensures that flood risk is avoided wherever possible and managed effectively where development is necessary. It promotes the use of nature-based solutions and green and blue infrastructure to reduce flood risk while delivering wider environmental benefits, including improved biodiversity, water quality and amenity. 3.4.4 Flood Risk Assessments and drainage strategies should be informed by the latest Strategic Flood Risk Assessment, Warwickshire County Council’s Local Flood Risk Management Strategy, and advice from the Local Lead Flood Authority (LLFA). Managing flood risk is