The London Tideway Tunnels project is finally set to get underway after Thames Water awarded its first major construction contract to the MVB consortium last month.
This first award in building London’s new mega sewer means that MVB − comprising Morgan Est, Vinci Construction Grands Projets and Bachy Soletanche − will start construction on the £400M Lee Tunnel in April.
Thames Water made the announcement, on what it claims is the single largest construction contract from the water industry in the 20 years since privatisation, just before Christmas and said it formed a key component of the whole scheme.
The 7km long, 7m diameter, 75m deep sewer will take wastewater east from Abbey Mills Pumping Station to Beckton Sewage Treatment Works. This first tunnel will prevent over 16Mt of sewage entering the River Lee, a tributary of the Thames.
“It’s a good start. The Lee Tunnel has quite a high percentage benefit − it’s substantially less in length and cost [than the Thames Tunnel] and offers some benefit in the short term,” said Thames Water head of London Tideway Tunnels Phil Stride.
A major project
The Lee tunnel will cost £600M in total − including investigation, design and preparatory costs − and is set to be complete by 2014. The more complex 32km long Thames Tunnel is expected to go out to public consultation in July.
The design of this section is still under debate as Thames Water negotiates the best route to intercept the sewage that currently feeds into the Thames from 34 combined sewer overflows.
One option would be to take the flows from the Thames directly to Beckton, while Thames Water is still considering an alternative, shorter version, that would divert sewage to the Lee Tunnel for transfer to the treatment facility (NCE 12 November 2009).
“We’re working up the designs. The shorter option is still a possibility,” Stride told NCE. “The question we have to answer is how we can deliver the main components of the scheme in the most cost effective way.”
Stride added that a change of government could mean the logistics of its planning application faced uncertainty. There is a possibility the scheme could be submitted to the Labour promoted Infrastructure Planning Commission, but the Tories have said they would scrap it.