The engineering

Last updated: 24 July 2017

The engineering

At 25 kilometres long, up to 66 metres deep, and more than seven metres in diameter, the Thames Tideway Tunnel will be the biggest infrastructure project ever undertaken by the UK water industry.

It will generally follow the route of the River Thames to enable it to connect to the combined sewer overflows (CSOs) that are located along the riverbanks, passing underneath all other infrastructure in London and through a variety of different ground conditions.


The route and tunnel

Route and tunnel

Tideway has signed up a team of world-class contractors to offer sustainable and cost-effective methods of construction.

There will be three main 'drive sites' where tunnel boring machines are lowered in to the ground and driven below the river bed to construct the tunnel from the east, west and central locations.

Innovative engineering in the design phase has already reduced the tunnel from the initial 32 kilometres proposed, down to 25 kilometres, and reduced the number of construction sites needed from 45 to 24.

What is a tunnel boring machine?

A tunnel boring machine (TBM) excavates a circular tunnel using a rotating cutterhead, while simultaneously creating a tunnel wall using concrete segments. As it excavates it also transports material from behind the machine via a conveyor belt or pump, which is progressively extended as the machine moves.


Key part of a TBM

Key parts of TBM

The construction plan

Jobs & opportunities

Current positions available within the Thames Tideway Tunnel project include:

    News from other sources

    What people are saying about the Thames Tideway Tunnel project...


    • Crossrail mastermind in Thames clean-up - January 2017

      “This project is to unwind history a little and take time to rethink what the Thames can add to society and the economy"

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    • Super sewer aims to stop filth polluting the Thames - December 2016

      'London is famous for rain and the River Thames'

      Go to article

    • New pier launched for Tideway - December 2016

      'A new pier has been launched in the heart of London after months of challenging construction work on the River Thames'

      Go to article