4 minute read time.

London’s sewage system was designed in the 1860s for a city of around 4 million. There are now around 8 million people living in the capital. Although the system still works well, it’s struggling to cope in terms of capacity. The result is that millions of tonnes of sewage pour into the river Thames every year.

The Thames Tideway Tunnel is a 25km tunnel stretching from Acton in west London to Abbey Mills pumping station in Newham in east London, where it will connect to the Lee Tunnel.  Tideway will connect with 34 of the most polluting overflow points along the river - collecting sewage that currently overflows into the Thames and transfer it to Beckton for treatment.

Project Progress

The project is almost 90 per cent complete and focus is now on preparations for system commissioning which will start in 2024, ahead of full operation in 2025.

Key construction milestones achieved include the completion of the new tunnel network deep below London. Installation of the secondary lining of the Eastern tunnel is nearing completion thus completing secondary lining across the project.   In the Western section of the project sites are also nearing completion with the first public realm now opened at Putney Embankment.

Engineering and Design

The Thames Tideway Tunnel is approximately 25km long, up to 66m deep and ~7m in diameter.  It largely follows the route of the river Thames and goes through challenging ground conditions including chalk and clay.

The tunnels were driven using 6 tunnel boring machines from three main ‘drive shafts’ with an additional 18 sites sunk along the route to connect to the existing sewage network.

Many innovations have been developed and deployed across the project. One example is an innovative, first of its kind electrically-powered hydrofraise diaphragm walling machine was used to install three shafts in the Eastern section of the tunnel.  The Hydrofraise uses mains electricity instead of diesel and reduces the carbon footprint and minimises disruption to neighbours.

Safety and Risk Management

RightWay is a health, safety and wellbeing approach, and is embedded across the construction phase and specifically high-risk activities, including marine, tunnelling, secondary lining, MEICA installation and site commissioning.

The Project aim is to target zero fatalities or serious injuries, off or on-site and will be achieved by setting new standards for health, safety and wellbeing.

Everyone working on the Tideway Project attends the transformational EPIC programme an interactive immersive induction.  To date, over 23,000 people have attended EPIC and over 1,400 have attended EPIC Logistics, a specific induction course for HGV drivers delivering to Tideway sites. 

Mental Health of the workforce is a major driver for the project and Tideway has been supported by the Mates in Mind programme, Mental Health First Aiders, Mental Health First Aider Networks, and support from local services.

A focus on Health and Wellbeing is maintained to achieve relative parity with Safety and to minimise and mitigate any health risks whilst supporting the wider health and wellbeing of the workforce.

Impact on Transportation and Infrastructure

Tideway has transported over 5.6 million tonnes of materials by river, removing approximately 670,000 HGV journeys from London’s Road network.

With the completion of tunnelling, Tideway have exceeded their legacy commitment to transport 90 per cent of material excavated to create the main tunnel by transporting 100 per cent of main tunnel arisings by river.

Tideway have also committed to improving Health & Safety on the river for Tideway river transport workers. A total of 103 individuals successfully passed the innovative boat master competency validation at HR Wallingford ship simulation centre.

Engagement with the local community

A good example of Tideway’s community engagement is in the creation of new areas of public realm to connect the capital’s residents and visitors with the river more closely than is currently possible. Three acres of new public realm are being created along the route of the River Thames at seven different locations including the Chelsea, Victoria and Albert embankments created by Sir Joseph Bazalgette when he created London’s sewerage system more than 150 years ago.

The new public realm will be landscaped and home to thought-provoking works of public art. Artists from across the country have been tasked to work with the local community and take inspiration from the local area in developing their work to respond to the local area’s heritage and history.

Tideway is committed to giving back to the communities in which they work, leaving a lasting legacy for London through community partnerships, volunteering and charitable donations. They have developed long-term partnerships to help them achieve their legacy commitment to support local communities and their vision of reconnecting London with the River Thames.

Since the start of the project, Tideway's community investment programme has helped over 48,000 people, supported 512 organisations and led to 33,268 hours of volunteering by their staff. The social impact study on Tideway’s legacy programme found that their volunteering delivered a social value of £5.6 million – based on charities not having to do the work and the wellbeing boost to their volunteers.

The Thames Tideway Tunnel will clean up one of London’s greatest natural assets, the iconic River Thames, improve the quality of life for all Londoners and protect it for generations to come.  

Want to find out more? IET Berkshire are hosting an event Tideway – reconnecting Londoners with the River Thames on Thursday 21st September at UTC Reading in Reading, UK where Stuart Grant, Head of Commercial Agreements & Property for the Tideway Project will give an overview of construction progress of the 'Super Sewer' and a forward look to its commissioning and delivery of wider legacy benefits.

Unfortunately the above event has now been postponed to a future date. Keep an eye on the events list for IET Berkshire for details of the new date