Our southern team have recently finished work for Thames Water cleaning and inspecting outflow tunnels at Coppermills Treatment Works in Walthamstow.

The team have worked incredibly hard to manually clear two adjacent tunnels of an estimated 300 tonnes of silt. These tunnels are a challenging environment to work in, with a maximum height of 1.5m and each being 240m in length.

To drain and isolate the tunnels to make them safe to work in, the project required large overpumping from the treatment works, bypassing the tunnels.

The overpumping set-up was capable of taking 150Mld and required 2 road crossings. This was a crucial element of work to deliver successfully, as failure would have resulted in up to 3000,000 customers without water.