Flood modelling for Wincanton Anaerobic Digestion Plant

Challenge

The proposal comprises the installation of an Anaerobic Digestion (AD) plant, with an intake of feedstock of circa 69,000 tonnes per annum, with approximately two thirds comprising of the silage and manure sourced from surrounding farms.

Solution

The site is located alongside the River Cale, which has extensive floodplain and results in a large part of the site being located in Flood Zone 3. A small stream also flows through the centre of the site, which introduces another source of floodwater. The site was therefore significantly constrained by flooding, which needed careful consideration to meet both client and regulator needs.

We were responsible for the preparation of a Flood Risk Assessment, which included flood modelling to challenge the existing flood maps and improve development opportunities at the site.

Impact

Various flood management measures were required, including a raised development platform, floodplain compensation and the realignment of the stream. We also needed a surface water drainage strategy, which was based on the principles of Sustainable Drainage Systems (SUDS) and designed to manage runoff rates and improve water quality.