Environment Minister Richard Benyon confirmed in the House of Commons yesterday that the projected cost of Thames Water's ‘super-sewer’ tunnel has risen from £3.6 billion to £4.1 billion. This morning the company has just announced the revised routes for the tunnel and the start of a new consultation phase.

The14-week consultation which starts today on Thames Water’s revised plans for the proposed Thames Tunnel looks set to receive further significant response from vocal and well-organised opposers of the scheme.

Thames Water’s site selection process has identified three ‘main drive shaft’ sites, needed to launch the machines that will burrow the 7.2 metre diameter wide tunnel, broadly following the route of the river bed, from Acton to Abbey Mills, near Stratford.

Thames Water updated list of preferred sites for the tunnel’s construction and operation are:

Carnwath Road Riverside in Fulham

Whiffin Wharf, Hurlingham Wharf and Carnwath Road Industrial Estate have together replaced Barn Elms Playing Fields, the previously preferred site on the  Richmond/Wandsworth border.

Kirtling Street in Battersea

The proposed site covers land currently occupied by warehouses (some of which are vacant), offices and a ready-mix concrete works. It replaces Tideway Walk, the previously preferred site. In March 2011 a developer received planning permission to develop the Tideway Walk site, mainly for housing. Work then started on site, requiring the Thames Tunnel team to find an alternative location.

Chambers Wharf in Bermondsey

 A riverside brownfield development site, replacing King’s Stairs Gardens, a park in nearby Rotherhithe. The site is proposed to be used to launch a tunnelling boring machine travelling to Abbey Mills, a Thames Water operational site near Stratford. The Chambers Wharf site is also needed to receive a smaller tunnelling machine, departing from Thames Water’s sewage pumping station in Greenwich High Road.

The updated proposals also include reduced use of greenfield sites and a plan for 90 per cent of soil from main tunnel ‘drive sites’ to be transported away by barge or rail.

Excluding minor works, 22 sites are needed to construct the Thames Tunnel, compared to the 23 envisaged a year ago.

In addition to the three main tunnel drive sites, and two main tunnel reception sites a total of 17 other, smaller construction sites are also proposed to intercept or control the flows from the 34 Combined Sewer Overflows into the main tunnel.

Customer bills will rise even further

Phil Stride, Head of London Tideway Tunnels at Thames Water, said:

"We have been working hard to refine our original plans, where possible, in the light of the concerns people have raised with us. This has resulted in some significant changes, also reflecting our absolute determination to balance overall disruption with the equally important need to ensure that the price tag remains affordable for our customers.

"There are no easy choices when it comes to selecting construction sites, but our focus during this latest phase of consultation will be to work with communities around our revised list of preferred sites to ensure we understand and address their concerns effectively. It is particularly important that we listen to local people’s views on what individual sites should look and feel like after construction work has finished."

The changes to Thames Water's original plans mean that main construction work for the tunnel is now provisionally scheduled to begin in 2016 and expected to last six years.

The company’s revised estimate for the total capital cost of the project is £4.1bn at 2011 prices, excluding inflation.

Thames Water said the project’s construction would not have any impact on bills before 2013 at the earliest. The maximum impact is likely to come a few years later and is now estimated to be in a central range of £70-80 per year. Previous estimates put the price hike for customers at  £60-65 extra a year.

Deadline for the submission of responses to the new consultation is 10th February 2012.