Maynard Reservoir


Project: Maynard Reservoir

Scope: Install Secondary Isolation

Location: Warwick Reservoir

To allow a safe manned access into the Maynard reservoir connecting pipes we had to design and install a secondary means of isolation for the eventuality of the primary penstocks failing. Our design was in essence a giant, reinforced, composite biscuit with a unique outer seal device.

The design and load specifications were created on our Solidworks design programme and submitted to Barhale and Thames Water engineers for approval. The design was approved by Thames Water and construction began.

The new isolation plates were much smaller, lighter and more effective than anything that had been installed previously. Composite seals were retained by lightweight plates. The whole construction was braced with lightweight steel sections to give a remarkable strength to weight ratio and the support braces that were fabricated from the same material, were bolted circumferentially to the wall of the pipes.

The quality of design & build had to be of the highest standard as they were required to ensure safe exit of con-fined space operatives in the event of penstock failure and were designed to withstand a 10m head of water, with the operational requirement being to hold back a 5m head of water.

Our divers lowered the plates into the access shaft using buoyancy aids and then manoeuvred them into a precise position within the mouth of the tunnel, ensuring they were perpendicular to the wall in all planes before being secured. Barhale successfully completed their works and a week later our dive team returned to remove the seals, thereby bringing the tunnels back into normal operation.

Testimonial: WSG has provided an excellent service on my projects, from ROV surveys to installing secondary isolation plates in reservoirs. WSG/Tunnel Vision are very professional and a pleasure to work with.

Andy Simpson– Client