Our solution

Last updated: 17 July 2017

Our solution

Tideway are upgrading London's sewerage system to cope with the demands of the city well into the 22nd century.

After years of study, construction work for the new 25 kilometre interception, storage and transfer tunnel running up to 66 metres below the river, known as the Thames Tideway Tunnel.

Starting in west London, the main tunnel generally follows the route of the River Thames to Limehouse, where it then continues north-east to Abbey Mills Pumping Station near Stratford. There it will be connected to the Lee Tunnel, which will transfer the sewage to Beckton Sewage Treatment Works.

Overflows of untreated sewage into the tidal River Thames add up to tens of millions of tonnes every year. This is unacceptable and the Thames Tideway Tunnel will clean up one of the world’s iconic rivers. 

 

Route and tunnel

Tunnel route

What happens now?

London's sewerage system relies on an integrated network of combined sewer overflows (CSOs). At the time it was built, the CSOs would release flows through discharge points along the river during heavy storms. Originally, this would happen once or twice a year, it now happens on a weekly basis and no longer requires a storm to trigger overflows.


Our plan

By intercepting the sewage before it enters the river, the Thames Tideway Tunnel will help prevent the tidal River Thames from being polluted with untreated sewage which can stay in the river for up to three months before the ebb and flow of the tide finally takes it out to sea.


The solution in brief

Built from three main construction drive sites in Fulham, Battersea and Southwark, the Thames Tideway Tunnel is expected to take up to seven years to build, at a cost of £4.2 billion (2014 prices). It will require the use of 24 construction sites, 11 of which are located along the river bank. The main tunnelling work will start in 2016.


Volumes of discharges from London's combined sewer overflows (CSOs)

Existing system

Existing system

N.B. This diagram is for illustration purposes only.
For a more accurate visualisation, please download the chart set


Lee Tunnel and STW improvements

Lee Tunnel and STW Improvements

N.B. This diagram is for illustration purposes only.
For a more accurate visualisation, please download the chart set.


Thames Tideway Tunnel and STW improvements

Tideway Tunnel and STW Improvements

N.B. This diagram is for illustration purposes only.
For a more accurate visualisation, please download the chart set.