What is a Flood Risk Assessment?

Flood Risk Assessments (FRA) are becoming a very important part of the planning permission process. It interlocks with other areas of the planning process, and could cause weeks or months of delays if not done from the beginning. But what is a Flood Risk Assessment?

A Flood Risk Assessment is a series of tests that are carried out to assess the level of flood risk of a given location. The assessment will check for flooding caused by groundwater, surface water, artificial water, rivers, streams, sewers and drains. Professional Flood Risk Assessments have to written up by Civil Engineering Consultants. They can cover anything from a single house to an entire area.

Photo by Matej Kastelic / Shutterstock.com

When do you need a Flood Risk Assessment?

If your home or part of the area you live in is at risk of flooding, you will be classed under one of four different Flood Zones according to Planning Practice Guidance. You will require a Flood risk Assessment if you are in:

  • Areas in Flood Zones 2 or 3 including minor development and change of use more than 1 hectare (equivalent to 10,000 square metres) in Flood Zone 1.
  • An area with less than 1 hectare in Flood Zone 1, including a change of use in development type to a more vulnerable class (eg from commercial to residential), where they could be affected by sources of flooding other than rivers and the sea (eg, surface water drains, reservoirs).
  • Areas within Flood Zone 1 which have critical drainage problems as notified by the Environment Agency.

If your planned development is in Zone 2 or 3 areas, you also need to carry out extra testing such as sequential and exception tests, as well as meeting additional flood resistance and resilience requirements where they need to.

What to look out for in your Flood Risk Assessment

There will be a lot of information given in a Flood Risk Assessment, but you will need to keep an eye out for some key information such as: how the flood risks will affect the proposed building work; if the development is still appropriate in the location with the new information; if the flood risk is too great for the proposed building and if the new building will cause flood risks in other areas.