Chard Reservoir Reservoir Safety Upgrade
Project : Reservoir Safety Works
Client : Somerset Council
Date of Services : 2020 to 2025
Scope of work
- A feasibility study to look at the various options of how the spillway capacity could be increased, including attending consultation meetings with various stakeholders
- Detailed design and tender documents
- Engineering support during construction
- Reservoir Act “Qualified Civil Engineer” to oversee the design and construction and certify the completed works
- Support to environmental and planning consultants to provide a coordinated service
Project description
Chard Reservoir in Somerset retains 1M m3 of water behind a 12m-high earthfill embankment. This historic reservoir was constructed in 1842, originally to supply water for the Chard Canal between Chard and Taunton. The reservoir is now an amenity lake within a Local Nature Reserve and is used mainly for fishing.
The Chard Reservoir Scheme was initiated following statutory recommendations made by the Inspecting Engineer in 2018. Stillwater Associates was commissioned to carry out a risk-based assessment of the reservoir. The assessment identified the need for modifications to the existing overflow stilling basin, installing erosion protection along the downstream face of the embankment, and raising the embankment crest to prevent overflowing during extreme flood events. The various elements of the scheme were optimised by laboratory-based physical hydraulic model testing of the dam and overflow arrangements.
Stillwater Associates was appointed as Principal Designer to prepare the detailed design for the scheme, followed by the construction tender process, supervision and technical assistance during construction and contract management. We also fulfilled the role of Qualified Civil Engineer (QCE) throughout the design and construction phases. We worked closely with Somerset Council to deliver the design, which included embankment crest raising through the construction of a precast concrete crest wall, remodelling of the overflow stilling basin and protection of the embankment downstream face. During the construction phase, we provided technical engineering support throughout and worked alongside the Principal Contractor, Kier plc, and Somerset Council’s appointed Project Manager, WSP. The reservoir safety upgrade project was successfully completed in July 2025.
