As part of our series delving into the Tunnels and Aqueduct Programme where we are looking at the different projects within the programme, our first stop is Wraysbury Reservoir Inlet and Valve works, Berkshire. Barhale was instructed to undertake works as part of Thames Water’s 10-year periodic inspection programme to isolate, drain, clean, inspect and repair the inlet tunnel, which draws water into the reservoir from Datchet Pumping Station. We were also tasked with replacing the existing 72” butterfly valve with a new DN1800 butterfly valve within a 35m deep shaft.

Some of the works that were carried out included a double isolation through a combination of valve closures, blank plate installations. Also, cleaning was undertaken by using a DISAB tanker and 6” hosing.

In terms of replacing the existing 72” butterfly valve, we removed the existing bolts around the valve flange using handheld guns, with angle grinders to remove any bolts that were suffering from heavy delamination.

The initial plan of the installation of the new DN1800 valve involved using a PCD converter plate to connect a 72” Table D flange upstream to a DN1800 PN16 flange downstream for the new valve installation. However, upon lifting the new PCD converter plate into the shaft, it became apparent that the flange drillings did not align. After discussions with Thames Water, the decision was made to modify the upstream flange drillings to accommodate the new valve. The downstream flange was cut off using a wire saw, leaving sufficient pipework length for installation of the flange adaptor and thrust restraints.

Seb Burke, Site Agent (Southern Region) shared his thoughts on the project:

“This project exhibited how our site teams live and breathe the Barhale values. With some quite significant challenges, including problems with our supply chain partner, we were undeterred and our directly employed workforce successfully completed the installation through perseverance and expertise.”

Well done to all our team on continuing to deliver successfully ensuring Thames Water continue to ensure asset resilience for years to come.