Sunnyhurst and Earnsdale Impounding Reservoirs

Winner of the “Institute of Civil Engineers” Medium Sized Projects of the Year in 2017.

Contract Title: Earnsdale & Sunnyhurst Impounding Reservoirs’s
Client: United Utilities plc
Dates: Completed Dec 2017
Value: £3,246,000
Form of Contract: NEC3

Works included Earthworks to existing reservoirs, installing a 350mm diameter pipeline across the basin to the valve tower, constructing new reinforced concrete structures and foundations such as a coanda screen with a reno mattress channel and overflow structure. Installing a 750mm diameter outflow pipeline to Earnsdale reservoir haul road and reinstatement works.

Earnsdale reservoir had to be upgraded to cope with the increased intake of water. This included constructing a large earth berm onto the side of the embankment to act as a counterweight and the construction of filter drainage layer to eventually seal the embankment. The earth berm was constructed on concrete deep soil mixed platforms using tencate ecowall units and layers of geotextile lapped into the embankment. It is the first time this technique has been used in the UK. Askam also installed a new scour pipe facility at Earnsdale.