Thames Water's planned improvements will limit pollution arising from combined sewer overflows discharging into the tidal River Thames.
London’s current sewerage system collects both domestic waste and rainwater. When it rains, the sewer overflows and discharges into the tidal Thames through 57 combined sewer overflows (CSOs).
Around 39 million tonnes of untreated sewage is discharged via CSOs to the tidal Thames each year. Discharges occur up to 60 times a year, after as little as two millimetres of rain. Thirty-six CSOs are unsatisfactory and need to be addressed by Thames Water.
London Tideway Improvements scheme will address this problem by improving London's five sewage treatment works and building two tunnels (the Lee Tunnel and the Thames Tideway Tunnel) to intercept discharge from the worst CSOs.
As a government advisor, we support the government’s position on the need for the Thames Tideway Tunnel as set out in its Ministerial statement on 3 November 2011. We consider the London Tideway Improvements scheme to be the best solution to limit pollution arising from CSOs discharging into the Thames Tideway in London.
Evidence shows that the London Tideway Tunnels will:
- improve water quality
- reduce the health risks to people who use the river
Water quality standards
We organised a 'round table' discussion on 31 May 2012, with independent fisheries experts, to review the water quality standards for the tidal River Thames. The River Thames is still struggling to meet its current water quality standards, which are set at the right level to protect its valuable ecology.
The fisheries experts involved in the review were:
- Peter Spillett (Chair)
- Steve Axford
- Steve Colclough (SC2)
- Ian Johnson (WRc)
- Andy Turnpenny (Turnpenny Horsfield Associates)
- Daryl Clifton-Dey (Environment Agency)
- Tom Cousins (Environment Agency)
They were joined by Chris Binnie, former chair of the Thames Tideway Strategic Study, and Environment Agency representatives.
Thames Tideway web links