Working in partnership with Frog Environmental, Team Van Oord has successfully deployed ‘silt wattles’ to help control sediment on a flood alleviation scheme in West Sussex.
“The innovative solution has been used at the Clay’s Lake Flood Prevention Scheme which Team Van Oord is delivering on behalf of the Environment Agency,” TVO said in its release.
The Clay’s Lake scheme comprises the removal of an existing dam which is being replaced with a larger dam. This will increase the lake’s capacity from 10,000 cubic meters to nearly 400,000 cubic metres, thereby reducing the risk of flooding to more than 280 homes in the area, and to Gatwick Airport.
Natural silt wattles are used as check dams in rivers, ditches, swales and gullies to reduce the speed of water and aid natural sediment deposition. The natural media supports silt trapping and can also be used in conjunction with a floc mat to enhance sediment capture and reduce downstream turbidity.
The design of silt wattles, which are manufactured in the UK by Frog Environmental, ensures they are malleable and will fit to the contour of uneven surfaces, where they can be staked in place or tied off.
Other innovative techniques to reduce silt pollution are being trialed at Clays Lake, these include Water Lynx blocks to aid water settlement and flocculation mats to trap silt in water before entering the watercourse.