Flood Risk: Severn Beach


A project for RSL Merlin looking at the possible constraints for development in the Severn Beach area North West of Bristol.

This required careful consideration of Strategic Flood Risk Assessments for South Gloucestershire, Bristol, and the joint investigations into Severnside.  In addition to local authorities the Lower Severn Drainage Board also has a role and is a consultee, being responsible for maintenance to the linked rhynes that feed surface water to the River Severn.

The most significant fluvial flood risk is from rhyne blocking, which occurs when high tides combine with high river flows, preventing discharge from the local drainage system.  Risk from this factor can be managed in Severn Beach, but the entire areas is treated as being in Flood Zone 3, as a consequence of the risk of breach to the tidal defence structures.  These are generally regarded as low grade, and often incidental having been provided for other purposes (the railway embankment being a good example).

The long term future of the community  is  dependent on major investment in flood defence.  Current Environment Agency policy is under development, but appears to be settling on “Hold the Line.”  While this offers some reassurance there is no current commitment or process to deliver the necessary funding.  At present local planners seem to defer to the Environment Agency and although redevelopment can be negotiated the terms and conditions can be onerous and depend upon careful evaluation of the flood risk.


Client: Merlin