At the request of Simon Hughes MP and Save Your Riverside, Thames Water recently hosted a visit to their Abbey Mills facility to explain on the ground why they have concerns about using it as a drive site for the main tunnel.
If Thames Water were to use Abbey Mills as the main drive site for the eastern spur of the tunnel instead of Chambers Wharf, thousands of residents and children in local schools both north and south of the river could be spared years of unnecessary misery.
Thames Water is concerned that the tidal nature of the River Lee and the twisty nature of the channel would restrict spoil removal operations to 500 tonne barges (one third the size of those they plan to use at Chambers Wharf) and there would be increased project risks such as bad weather hampering spoil removal or even a barge sinking. However, at Abbey Mills, barges have already been used to remove the spoil from the recently excavated shaft which is to receive the tunnel boring machine for the Lee Tunnel currently being driven from Beckton.
Furthermore, Thames Water did admit that if Abbey Mills were used as a main drive site for the super sewer instead of Chambers Wharf, it would be technically possible to use 4 or 5 barges a day from Abbey Mills which would be enough to remove tunnel spoil without risking interrupting the progress of the tunnel boring machine. The site at Abbey Mills also has enough space to store 4 days’ worth of spoil, together with concrete tunnel segments awaiting use.
The visit demonstrated that although Thames Water now prefer to drive the tunnel from Chambers Wharf, it is perfectly possible for them to drive it from Abbey Mills instead.
Save Your Riverside argues that Thames Water do not need a site in Southwark at all.