Embankment piling work to begin at Wilstone Reservoir

The works will start week commencing 30 June. Stretching for 1,350 metres, the historic embankments at Wilstone Reservoir are among the longest of the 74 major reservoirs in the Trust’s care.

The project

The project, estimated to cost £6 million, started in March with site preparations, and is expected to be completed in March 2026. The piling work is expected to take around five months.

Built in 1802 to supply water to the Wendover Arm of the Grand Union Canal, Wilstone Reservoir is part of the Tring Reservoirs Nature Reserve Site of Special Scientific Interest (SSSI).  At 119 acres (48 hectares), Wilstone is the largest of the four reservoirs. It is up to 18 feet (5.5 metres) deep and has the capacity to hold over one million mega litres of water, the equivalent of over 450 Olympic sized swimming pools. The reservoir has two five-metre wide embankments stretching for a total of 1,350 metres and ranging in height from two to eight metres.

An important place

Ros Daniels, Canal & River Trust’s London & South East director, explains: “Wilstone Reservoir provides an important place for water storage for the Grand Union Canal and has also become a popular site for angling, walking and bird watching. 

“Our programme of statutory safety works at Wilstone Reservoir are required under the Reservoir Act. They include creating a temporary access track and driving two thousand 11-metre long steel sheet piles into the reservoir’s embankments, to strengthen them and secure the reservoir for the future. 

“Our construction contractor Kier will use land-based equipment to carry out the works. This means we’ve been able to keep the water in the reservoir, so it can continue to supply water to the canal. Most of the piling work will be carried out using a method that reduces noise to minimise disruption to wildlife and people. 

 “To facilitate the works, we’ve had to temporarily close the footpath that runs along the top of the reservoir dam.  Pedestrians are being diverted through the field next to the reservoir, maintaining access to the farm shop and café, which will remain open throughout the works.  We plan to close the Wilstone Reservoir car park in early September for around four months, while we complete the piling work and build a new footpath along the top of the dam.

 “We will also need to temporarily close the road next to Wilstone Reservoir’s car park for approximately four weeks at the beginning of September 2025. A traffic diversion will be in place, and the farm shop and café will remain accessible.  It won’t be possible to fish at the reservoir during the main construction element of the works from May 2025 to March 2026.

 “The reservoir is an important wildlife site and once the engineering works are completed, we’ll carry out some improvements to the reed beds, and we’ll replace the nine small and medium-sized trees which unfortunately had be removed ahead of the works.”