Local Requirements - Flood Risk Assessment (Householder)

Types of application or development that require this information

Householder development in flood zones 2 and 3 (including sheds, garages and games rooms etc within the curtilage)

Excluding proposals for:

A Flood Risk Assessment must be submitted which includes:

An assessment of the flood risk for the development (considering all sources of flooding not just rivers and including an allowance for climate change). If your extension is in an area with increased flood risk as a result of multiple minor extensions in the area, you need to include an assessment of the off-site flood risk. Check with the Drainage Team if this applies to your development.
The estimated flood level for your development: the 1 in 100 year river flood level. Plans must be provided showing the finished floor levels and estimated flood levels. Floor levels must either be no lower than existing floor levels or 300 millimetres above the estimated flood level. If the floor levels aren’t going to be 300mm you need to check with your local drainage authority if you also need to take flood resistance and resilience measures. The assessment must have all levels in relation to Ordnance Datum (the height above average sea level). You may be able to get this information from Ordnance Survey. If not you’ll need to get a land survey carried out by a qualified surveyor.
Details of your flood resilience and resistance plans. Plans need to show how you’ve made efforts to ensure the development won’t be flooded by surface water runoff, for example by diverting surface water away from the property or by using flood gates.

Make sure your flood resistance and resilience plans are in line with the guidance on improving the flood performance of new buildings.

National Planning Policy Framework - Chapter 14: Meeting the challenge of climate change, flooding and coastal change
National Planning Practice Guidance: Flood risk and coastal change
Core Strategy - Policy EN7: Flood Risk