Thames Water has said this week that the cost of the Thames Tunnel super-sewer, currently the subject of a public consultation could nearly double. The projected cost has soared from £2bn to between £3.6bn and £4.3bn.

The new coalition Government has recently announced its support for the Thames Tunnel. As a Nationally Significant Infrastructure Project, proposals for the Tunnel have also been submitted to the Infrastructure Planning Commission.

Phil Stride, Head of London Tideway Tunnels, said:

“Our preferred route and sites for the Thames Tunnel are the result of months of design development and methodical planning. I am very grateful to everyone who has helped over the last two years to get us to this important milestone.

A key focus for us has been to optimise the route of the tunnel and reduce the number of combined sewer overflows directly intercepted, to ensure we deliver the most cost-effective solution and minimise disruption.As a result, the number of construction sites we think we need for the preferred route is significantly fewer than our initial predictions.This will, of course, be of little consolation to those who will be directly affected by our preferred option, if included in our final proposals. From frequent meetings with them, I know many people have been waiting anxiously to hear the details of our plans and I am thankful for their patience.

I can also reassure them that the launch of the public consultation is the start of a journey of wider stakeholder involvement, not the end.

To complete the project on target by the end of 2020, we need to start construction no later than 2013. The programmed date for our submission of planning applications is mid-2012”.

Construction starts on Lee Tunnel

After months of preparation, major works on Thames Water's Lee Tunnel are due to start at the end of September with construction of the diaphragm wall for the overflow shaft. The overflow shaft at Beckton STW will be the first of four deep shafts that will be built for the project, three of which will be started this year. The MVB joint venture - Morgan Sindall, Vinci Construction Grands Projets and Bachy Soletanche-  will build all of the shafts using the diaphragm wall technique. The shafts will have diaphragm walls built to a depth of between 65m to 98m underground, making them the deepest ever built in Europe. Since relocating to Beckton STW, the Lee Tunnel team has been busy doing establishment works, such as site clearing and preparation. Before starting construction on the diaphragm wall, MVB is drilling 80 cores around the circumference of the overflow shaft to ensure they do not encounter any unexpected obstructions.