Chapel House Reservoir Cumbria | Dam Upgrade | Piling | Keller UK

Chapel House Reservoir Cumbria - Dam Upgrade

Built more than 100 years ago, the client required improvements in order to comply with a dam safety assessment. Water supply from the reservoir had to be maintained throughout the works and fish migration through the waterway undisturbed.

Following detailed stability assessment of the dam, Keller, acting as main contractor, constructed a low permeability cut-off wall through the middle of the dam, with a grout curtain which extended below this into rock. Improvements to the spillway, and construction of a new wave wall and access road, followed the Geotechnical works.

Prior to proceeding with site works, a detailed stability assessment of the dam was undertaken to ensure embankment stability during the works. Detailed design was conducted by Keller to demonstrate the proposed plant and methods would not cause failure of the dam.

A 101m long low permeability cut-off wall was constructed to both sides of the central spillway to 12m depth. Prior to excavating the cut-off wall, end of casing permeation grouting was conducted on the downstream side of the wall to treat significant voids and mitigate against the risk of slurry entering the watercourse. A line of Tube-a-Manchettes were installed to the upstream side of the cut-off wall and treatment undertaken using microfine grout to extend the low permeability barrier into the competent bedrock beneath the embankment and underlying gravels.

Improvements to the dam were completed by the construction of a highway grade road over the dam crest, construction of a wave wall along the full length of the dam, and remedial work to the masonry spillway, including rebuilding of several wall sections.

With careful monitoring of the embankment and water quality, Keller completed the works without causing interruption to water supply and allowed the client to place no restrictions on its customers throughout the remedial works.

Systems: Grouting / Dam Grouting / Slurry wall.

Client: United Utilities

Contractor: Keller Geotechnique

Engineer: Process Alliance

Year of Execution: 2013

Keller Geotechnique
Templar House
1 Sandbeck Court
Sandbeck Way
LS22 7BA

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