Do I Need a Flood Risk Assessment?

It depends on your proposed development site size and its location

Do I Need a Flood Risk Assessment?


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.


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.


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.


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.

Require a Flood Risk Assessment?

Sanderson Associates have enjoyed over 37 years in business, our Flood Risk Team have extensive experience completing Flood Risk Assessments in support of our clients major and minor developments throughout the whole of the UK.

We would be pleased to provide you with our competitive fee proposal for a Flood Risk or Flood Consequence Assessment, please call us on 01924 844080 or click here to complete our secure online form.

Do I Need a Flood Risk Assessment, Flood Risk Assessment, Flood Consequence Assessment
Flood Zone 1, Flood Zone 2, Flood Zone 3
Flood Risk Area, Flood Zone C1, Flood Zone C2, Flood Zone B
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