Pioneering work to slow the flow of water from the Quantock Hills down to the Somerset Levels is being funded by Somerset Rivers Authority.
The project is partly a reaction to three unusually intense, localised storms that raged near to West Bagborough, and over Aisholt Common and Great Wood, last May. Around 1,200 tonnes of soil and gravel were washed down gullies, blocking roads and culverts which it then took weeks to clear.
Fifteen woody dams are now being created along four gullies, and sections of silver birch trunk laid down in gullies, to hold back water and debris on Aisholt Common. Silver birch branches are also being woven into barriers that follow the contours of the land.
The project is a partnership between Quantock Hills AONB (Area of Outstanding Natural Beauty), the Farming and Wildlife Advisory Group SW (FWAG SW) and Somerset Rivers Authority (SRA). The SRA is using Growth Deal money from the Heart of the South West Local Enterprise Partnership.
Sarah Diacono, SRA Senior Manager, said: “We’ve now approved more than 90 applications for natural flood management schemes in the upper and mid catchments of the River Parrett and the River Tone, but this is the first time we’ve funded work on top of the Quantocks. The more of these schemes we have, the more we can help to reduce flood risks, so it’s excellent to keep spreading the net.”
The Aisholt Common work near Will’s Neck and Middle Hill is being done by Quantock Hills rangers Andy Stevenson and Owen Jones (pictured top right), with volunteers Don Hobson (pictured top left) of Lydeard St Lawrence and Chris Pleeth of Kingston St Mary.
Roy Hayes, a Hills to Levels project adviser with FWAG SW, recommended various techniques and designs after studying water flow-path maps. Mr Hayes said: “A lot of natural flood management works have been done in places that it’s difficult for members of the public to see, but as these woody debris dams and contour-weaves are on Quantocks common land and close to the Samaritans Way South West, we’re hoping they’ll serve as more visible demonstrations of what can be done to Slow the Flow.”
Silver birch trees have been chosen for felling and use in dams because they are an invasive species encroaching upon an open heathland Site of Special Scientific Interest (SSSI). Removal provides more light for ground flora and opens up grazing for Commoners.
Andy Stevenson said: “This pilot project is focusing on Aisholt Common, but we’re looking to do a lot more next autumn and winter, possibly trialling some other techniques, such as using rolls of coir matting as permeable barriers, putting cross-drains across paths, and installing logs as bunds to hold back water.
“With Slow the Flow and with the removal of silver birch, we’re taking the same approach. It’s about getting on top of a problem.”