Do I Need a Flood Risk Assessment?

England

If the proposed development site is over one hectare in size and located within Flood Zone 1 and for all proposals for new developments located in Flood Zones 2 and 3 a Flood Risk Assessment is required.

Scotland

If the proposed development site is considered to be located in a low to medium risk area and it falls in the upper end of the probability range (i.e. close to 0.5% which equates to a flood risk of 1 in 200 years) or where the nature of the development or local circumstances indicate heightened risk a Flood Risk Assessment is required.

For all proposed developments within the Scottish Environment Protection Agency Flood Zones (1 in 200 year or greater chance of flooding) a Flood Risk Assessment is required.

Wales

If the proposed development site is located within Flood Zones C1 or C2 then a Flood Consequence Assessment is required. In Flood Zone B a Flood Consequence Assessment may be required with the level of detail dependent upon the location and whether the site is outside the extreme flood event extents (1:1000 flood event). All developments greater than a single property or development over the threshold of 100 square metres will also require SAB approval. Sanderson Associates has coordinated SAB pre-applications for developments of all sizes. We provide this service for sites throughout Wales.

General

In all cases, the assessments undertaken are specific to each site and may be a screening study or for extension works (Level 1) through to a detailed quantitative flood risk report (Level 3) and may include existing drainage system assessment, watercourse modelling and flood defence Breach Analysis where specifically required.

Our expertise extends through to design of flood alleviation schemes for proposed developments, including flood walls, attenuation ponds and dry basins to mitigate against the risk of flooding to both a proposed development and existing development where required.