SRA Annual Report 2018-19: Cannington Flood Alleviation Scheme case study (W1)

This scheme created a relief channel to divert flood water away from Cannington and better protect 200 homes and the A39. Three Hydro-Brake® flow control structures were installed along with CCTV and hydrometry/telemetry equipment.

An SRA contribution of £300,000 enabled this £4.35m scheme to go ahead, led by the Environment Agency in partnership with EDF, Cannington Parish Council, Wessex Water and Somerset County Council.

The data provided by telemetry show that the scheme is delivering benefits locally. The graphic below displays data collected at 15-minute intervals.

The line in green illustrates local rainfall. The trace shows – from the top in green – rainfall data collected locally. The scale on the left records levels in millimetres.

The results of this rainfall can be seen in the yellow line which represents upstream water levels. This vertical axis represents metres above ordnance datum (effectively ground level).

It highlights the consistent operation of the Hydro-Brakes® which restrict the volume of water passing down the main channel into the village of Cannington.

The side spill weir has also allowed water to pass into the flood relief channel on 10 occasions in the period  14 December 2017 to 10 May 2018. This is water that would otherwise have found its way into Cannington with all its restrictive culverts and channels – see the aerial view.