Flood Risk and Surface Water Management

We are responsible for making sure that new developments will not be affected by flooding or cause a risk of flooding to other properties.

The following information has been put together to help guide you through the validation requirements for flood risk and surface water management when applying for planning permission.

The rural nature of the South Hams and West Devon means there is limited drainage infrastructure and leaves many areas vulnerable to surface water flooding. If surface water is not managed effectively then continued development reduces the natural flood routes and increases the run-off volume and potential to cause flooding.

The National Planning Policy Framework (NPFF) requires the Planning Authority to ensure every development is safe from flooding and that it will not cause flooding. 

There are two elements to this: Flood Risk and Surface Water Management.

Flood Risk

The Environment Agency flood map identifies the three flood risk zones. If the development site is within a critical drainage area (CDA), flood zone 2 or flood zone 3, then a flood risk assessment (FRA) will be required. This must be carried by a suitably qualified professional

A FRA for smaller applications, like extensions, can be covered by Environment Agency Standing Advice. This can be done by yourself, Architect or Agent

Surface Water Management

Surface water run off needs to be managed to ensure it doesn't flood the development or cause downstream flooding. 

Therefore every planning application needs a Drainage Assessment that identifies how the surface water will be managed.

Surface Water Drainage Assessment (SWDA)

The level of detail varies depending on the development type, size and location. To help simplify the process we have developed a web-based validation and advice tool. The webtool can be used:

  • to identify what level of detail is required to meet the validation criteria,
  • provide advice on meeting the requirements and
  • to generate a Drainage Assessment for small developments as a single document ready to be submitted with your planning application; OR
  • to generate a site specific list that can be sent to the drainage engineer

Who should use the SWDA and Validation tool?

This replaces the validation checklist so is suitable for everyone and should be used by everyone that wishes to submit a planning application. Using this tool will help ensure it can be validated quickly and that the consultees have all the information to be able to assess the application.