Flood Risk: New Dwelling Close to the River Thames

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We were instructed on behalf of a client to assess the nature and potential significance of flood risk to land near the River Thames, upon which a new residential dwelling was being proposed. A FloodSmart Plus report was chosen so that detailed enquiries could be made with The Environment Agency.

The increase in surface water runoff from the site due to the impact of the proposed development was also considered. The flood risk assessment followed the standard outlined in the National Planning Policy Framework (NPPF, 2012).


A review of the data reported that the site had been identified as lying within the Environment Agency’s Flood Zone 3 with a greater than 1 in 100 year annual probability of river flooding. Risk screening using GeoSmart’s Groundwater Flood Risk Map indicated that the site was also at high risk of groundwater flooding.

The site has a history of flooding, with flood events from both groundwater and river sources being reported in the Local Authority’s Strategic Flood Risk Assessment (SFRA) and by the Environment Agency. As a result, insurance for the site may have been subject to additional premiums.

We have an excellent portfolio of flood risk assessment projects within the Thames region. Our consultant relationship and experience with Local Authorities coupled with an understanding of the groundwater flood risk within River Terrace Deposits of the River Thames enabled the consultant team to provide our client with a robust and well documented report.

A range of suitable mitigation measures to help reduce both the groundwater flood risk and the river flood risk posed by the nearby River Thames were provided as part of the report.

Our FloodSmart Plus Report increased the client’s awareness of the flood risks associated with the site, enabling them to make informed decisions regarding the proposed development scheme and increasing the likelihood of obtaining planning permission.

As a result of the submission of the report and implementation of the recommended mitigation measures, it is likely that any additional insurance premiums will be reduced.

Client Benefit

We undertook a FloodSmart Plus Report in 30 working days, inclusing liaison with the Environment Agency within the fixed price of £1,195 plus VAT.

This allowed an informed decision regarding the client’s proposed development scheme to be made and increasing the likelihood of obtaining planning permission.