Tideway | Cost of London’s super sewer hits £4.5bn
26 Apr, 2023 By Rob Hakimian
Tideway has updated its cost estimate for the Thames Tideway Tunnel to £4.5bn, taking into account the remaining work programme and the impacts of inflation.
The super sewer project was initially costed at £3.52bn in 2014, but that figure has steadily crept up over the course of its construction. The latest increase represents a circa 2% rise in cost since its last report at the end of the 2021/22 financial year.
Despite the difficulties, the work is now nearing 90% completion and is on course to be handed over to Thames Water in the second half of 2025. Tideway has confirmed that sewage overflows will start to be diverted away from the Thames and into the new 25km sewer from 2024.
Tunnelling on the sewer completed in April 2022 and primary lining across the entire project shortly after. Secondary lining for the 7km western section completed in November, while secondary lining for the eastern section is underway.
Final works will include shoring up the connections between all the routes and testing the infrastructure.
Work on the east section of the Tideway project will be delivered by a joint venture between Costain, Vinci Construction Grands Projets and Bachy Soletanche. In the central section, FLO, a joint venture between Ferrovial and Laing O’Rourke, is carrying out the work. The western section is overseen by BMB, a joint venture between Bam Nuttall, Morgan Sindall and Balfour Beatty.
Tideway chief technical officer Roger Bailey said: “Over the past 12 months, we’ve hit some major milestones on the Tideway project as we work toward a healthier River Thames – not least, finishing the primary tunnelling.
“Elsewhere, we’re now beginning to cap our shafts, we’re making good progress on the secondary lining, and the new public spaces we’re building out into the river are really taking shape.
“Next year, as we begin testing and commissioning the super sewer, sewage overflows will be diverted away from the River Thames and into the tunnel for the first time – beginning to realise our ultimate goal of a healthier river environment for London.”