All our Flood Risk Assessments are carried out by a highly experienced Chartered Engineer fully up to date and in tune with latest policy guidance. This ensures our FRA’s are carried out to exceptional quality standards holding the greatest chance of being accepted first time around. We pride ourselves on quick turnaround times and will work with you to ensure any flooding implications on development proposals are fully understood and suitable masterplan amendment made. Where mitigation measures are required, we look to provide solutions which are pragmatic, cost-effective and integrated with development proposals.
We prepare all our Flood Risk Assessments in full accordance with National Planning Policy Framework (NPPF) guidance and actively work with clients to ensure their BREEAM and Code for Sustainable Homes targets are achieved.
Flood Risk Assessment
The purpose of a flood risk assessment is to assess the likelihood and impact of flooding at a given location and identify any mitigation measures that may negate the likelihood and impact of flooding should they be required.
Flood Risk Assessments should be prepared in accordance with National Planning Policy Framework (NPPF) guidance including reviewing a sites sensitivity to flooding from all possible sources including from rivers (fluvial flooding), the sea, surface water runoff (pluvial flooding), from ground water, from reservoirs and from blocked or burst sewers and water mains.
In preparing a Flood Risk Assessment, contact should be made with the Lead Local Flood Authority, Environment Agency and in some cases the Water and Highway Authority to obtain any historical flood event, modelling output or asset information relevant to the site.
Different types of development have different flood risk vulnerability classifications – residential development is more sensitive to flooding than a quarry for example. Mitigation measures adopted within a flood risk assessment must be reflective of a developments vulnerability and should be proportionate to the risks identified. Given the unpredictable nature of climate change, it is also necessary to include additional capacity and factors of safety (typically freeboard allowances) within a flood risk assessment to address increases in rainfall intensity and volume which may occur over a development’s lifetime.
Flood Risk Mapping
Review of flood mapping is the first step in understanding a developments flood risk potential. Flood risk mapping across the whole of the United Kingdom is provided free of charge and can be accessed on the following links below;
As of Government guidance (see; https://www.gov.uk/guidance/flood-risk-assessment-for-planning-applications), a flood risk assessment is required for planning if an area is known to be at risk of flooding (is within flood zones 2 or 3) or within flood zone 1 but larger than 1 ha in area.
Flood mapping across the United Kingdom is compiled using JFLOW software and generated using Lidar data often using relatively sparse spot level grids. This means whilst freely available flood mapping data presents a great starting point, on some sites close to flood zone boundaries, it may be necessary to prepare more detailed flood modelling to more precisely identify flooding extents. This information can be used to further tailor development proposals and flood mitigation measures.