How a super sewer is reconnecting people with the Thames

The Thames Tideway Tunnel, affectionately known as the Super Sewer, is an environmental project with the goal of cutting the amount of sewage currently entering the river by 95%.

The 16-mile (25km) tunnel is the third and final element of the London Tideway Improvements programme.

This aims to provide a comprehensive solution to the unacceptable level of sewage pollution in the tidal Thames.

Having nearly completed the construction phase, the focus now is on commissioning the system later this year.

A cleaner, healthier river

The hard engineering solution that was chosen is enabling us to deliver benefits sooner – and at a lower cost – than any of the other options proposed.

This project will not only divert millions of tonnes of raw sewage from the Thames – it will also significantly reduce the ingress of sewage-derived litter, benefiting the river’s ecology and its users.

We’re getting close to creating a cleaner, healthier river.

Resilience is at the heart of the project, so the tunnel has a 120-year design life. Over this time, significant changes in climate and population will affect its performance.

While it hasn’t been designed to withstand every possible scenario, modelling indicates that the tunnel will still provide good long-term resilience.

Reconnecting London to the Thames

I’m a Londoner and am proud to be bringing up my children in this amazing city.

But, until I joined Tideway nearly seven years ago, I – like many people in the capital – had never felt particularly connected to the Thames.

Before 2017, I hadn’t been in a boat on the river or even ventured down to the foreshore.

My experiences on this project have changed all that.

While our main goal is to deliver an engineering solution to protect the Thames, we have a broader vision: to reconnect Londoners with their river.

New ways of experiencing the river

We’ve been enabling this in several ways, including the creation of 1.2ha of new public space (equivalent in area to Trafalgar Square) at seven riverside locations.

These new embankments, featuring thoughtful architectural details and enhanced by the works of world-renowned artists, provide new vantage points from which people can enjoy the river.

The foreshores at Victoria Embankment, Chelsea Embankment and King Edward Memorial Park, Wapping, will even be floodable at high tide, giving visitors the chance to dip their toes into a cleaner Thames.

We are also opening sections of the Thames Path that have been closed to the public and improving the route wherever possible.

All of these enhancements will offer a greater connection to the river.

Creating green spaces

To reduce surface water runoff, we’re installing biodiverse roofs on our surface-level structures, like raised ventilation shafts and kiosks.

Once these are completed, we’ll have created more than 750m2 of habitat for nature on top of them.

Our kiosk at Barn Elms is also clad in materials designed to support plant growth and attract invertebrates. It could be the capital’s largest bug hotel.

We recently opened our new public realm at Putney, giving the community another place in which to gather by the river.

We chose a hard landscaping solution here and at most of our new spaces, because there are deep shafts beneath them that enable us to access and maintain the Super Sewer.

We’ve gone to great lengths to avoid removing trees. Where this hasn’t been possible, we’re planting two for each one cleared.

By the end of the project, we’ll have planted 550 trees, many of which will be semi-mature.

Going above and beyond

We have also been keen to look beyond our programme boundaries.

We’ve funded 63 projects designed to make the city cleaner and greener through the Our Space Award, delivered by Groundwork London.

We’re proud to have backed so many projects giving urban communities that were disconnected from nature better access to green spaces and helping others to improve their local neighbourhoods.

Lasting legacy

Going deep underground to experience the scale of the Tideway project makes you appreciate the vital role that engineers play in tackling some of our most pressing environmental crises.

As the work approaches completion, we’ve been reflecting on our successes and how we might have done things differently.

The lessons we’ve learnt should inform the whole infrastructure industry.

We’re leaving an asset that will soon be tackling a critical pollution problem and providing resilient infrastructure for at least the next 120 years.

Hard engineering projects and sustainable drainage systems (SuDS) are all part of the solution as we strive to develop sustainable, liveable cities into the next century.