Strategic Flood Risk Assessment - South Worcestershire ...

Estimated Attenuation Storage Volume (m 3 ) 1,500 – 2,152SUDS and the development site:1 in 100 year (plus climate change) 31.1SUDS TypeSource ControlInfiltrationDetentionFiltrationConveyancePotentialSuitabilityCommentsAll forms of source control are likely to be suitableMapping suggests high permeability at this site, site investigationsshould be carried out to assess potential for drainage by infiltrationMapping suggests that the site slopes are suitable for all forms ofdetentionAll forms of filtration are likely to be suitable.All forms of flow conveyance are likely to be suitableThis site is located within a flooding hotspot so all efforts should be made tominimise the rate and volume of runoff leaving the site.The site is not located within a groundwater source protection zone.Residential developments should provide at least two independent SUDS features inseries to provide a suitable level of water quality treatment.Flood Defences:None.Effects of Climate Change:Increased water levels in the River Avon. Increased rainfall intensities.Flood Risk Implications for Development:All development should be located within Flood Zone 1, unless appropriate inaccordance with NPPF Technical Guidance.A detailed site-specific flood risk assessment, including hazard mapping, will berequired for any development in Flood Zone 2, or for sites greater than 1ha in FloodZone 1.Proposed for residential use.Resilience measures will be required if buildings are situated in the flood risk area.Green infrastructure should be considered within the mitigation measures for surfacewater runoff from potential development.All development should be located within Flood Zone 1, unless appropriate inaccordance with NPPF Technical Guidance.Assessment for runoff should include allowance for climate change effects.New or re-development should adopt exemplar source control SUDS techniques toreduce the risk of frequent low impact flooding due to post-development runoff.The site falls within an area indicated to potentially be susceptible to groundwateremergence. Further assessment of groundwater risk would be required and anassessment of suitable surface water mitigation techniques should be made at thedetailed FRA level.Onsite attenuation schemes would need to be tested against the hydrograph of thereceiving watercourse to ensure flows are not exacerbated downstream within thecatchment.The Weston Road and High Street road, the main access roads to the site, are atrisk from fluvial flooding and surface water. Suitable alternative accessarrangements away from the floodplain will need to be investigated further.Demonstration that development at this location can be made safe.2012s5947 S Worcestershire Level 2 SFRA Update FINAL Report v1.0.doc 144