Thames Tideway Tunnel

A highly significant development for both London and the environmental sector, Thames Tideway Tunnel is the UK water’s industry’s biggest ever infrastructure project, and the first  to be delivered under  new Special Infrastructure Project (SIP) regulations. It will be essential in preventing tens of millions of tonnes of sewage overflowing and discharging into the River Thames every year.

Benefiting both Londoners and the river wildlife, the 66-metre-deep tunnel will follow the route of the river, stretching from Acton, west London to Abbey Mills pumping station, Newham, where it will connect to the Lee Tunnel.  

With tunneling starting in 2018, engineers are using three main ‘drive sites’. In this case, six tunnel boring machines (TBMs) - each weighing 1,350 tonnes and 147 metres long - are transported along the river to where they’re needed and lowered into the ground via vertical shafts. Digging then commences in three sections – east, central and west – using a rotating cutterhead to dig.

At the same time, the TBM creates a tunnel wall behind it using concrete segments.  Waste material is removed using a conveyor belt or pump, depending on the ground conditions being solid or liquid.

The project will also result in the creation of three acres of public space along the Thames, giving people the opportunity to get closer to and enjoy the river.

Arcadis was appointed by Thames Water to perform due diligence testing for the project, thereby playing a vital role in assessing the health of the scheme on behalf of new funders being sought by Thames Water.  This enabled Thames Water to obtain the necessary funding to proceed, culminating in the transfer of the project to a new owner and funder in summer 2015. As a massive infrastructure project of significant importance, the scheme demanded the seamless blending of skills from across the Arcadis network, including:  

• Funding Business Advisory, risk and project cost specialists from the UK
• Water conveyance specialists from the USA
• Tunneling specialists from France

Arcadis now continues to provide Commercial Management and Project Controls as the scheme enters the delivery phase.