Green drainage must accompany Thames Tunnel

Opponents of Thames Supersewer urged to embrace both solutions after US presentation

A US wastewater expert has urged London to embrace the Thames Tunnel as the only solution to end the scandal of millions of tonnes of untreated sewage that enters the Thames each year through the city’s combined sewers. Members of the Thames Tunnel Now coalition, an expanding collective of environmental and amenity groups committed to cleaning up London’s river, have called upon opponents of the project to acknowledge that green infrastructure cannot be an alternative to the Thames Tunnel, but an important addition. This was the message from America following a presentation this week to water industry experts by Virgil Adderley, CSO programme manager for the city of Portland in Oregon.

Mr Adderley explained how Portland had initially sought to solve the pollution of the Willamette River system from Oregon’s 50 plus Combined Sewer Overflows (CSOs) by introducing a comprehensive system of Sustainable Urban Drainage (SuDs) without resorting to building a separate tunnel to capture the discharges. After more than 20 years of work and studies, the city of Portland concluded that while green drainage had an important role to play in less built up areas, it was no substitute for a tunnel.

In his presentation at Glaziers Hall, Southwark Virgil Adderley said: “Whatever we tried, we found that a large tunnel is needed to achieve acceptable levels of CSO control. Green infrastructure is important but only as a complimentary measure…”

Recently opponents of the Thames Tunnel have claimed it would be possible to retrofit London’s entire 150 year old drainage system to achieve total separation of sewage and rainwater. The Portland Study shows beyond any doubt that even in a much less densely populated environment, green infrastructure solutions alone cannot solve the problems of the Thames Tideway.

Chief Executive of London’s leading waterway charity, Thames21, Debbie Leach said: “Decades of study have made it crystal clear that nothing other than the Thames Tunnel would meet the standards set by the Environment Agency in the timescale set by the Government to end the scandalous pollution of the tidal Thames, which is now the subject of European Court action. Londoners deserve their river back and some of these groups now need to accept that the science is not on their side. Everyone who cares about having a clean river should get behind the Thames Tunnel, which needs to be built now”

The RSPB’s senior water policy officer, Phil Burston, said: “Portland shows that tackling urban drainage problems with green infrastructure (SuDs) can substantially reduce river pollution by up to 35% – but to eliminate the sewer overflows stifling the Thames and doing so much harm to its wildlife, tunnels and pumping stations combined with these green measures are the only real and practicable solution.”


 Notes to editors:

Thames Tunnel Now [] is an expanding collective of environmental and wildlife charities and amenity groups, which came together in October 2011 to call for an end to on-going sewage pollution in the River Thames through the construction of the Thames Tunnel project.  TTN includes:

  • The Ahoy Centre,
  • Angling Trust,
  • Angling Development Board,
  • Association of Thames Yacht Clubs
  • Barge Association,
  • Inland Waterways Association,
  • Canoe England,
  • Chiswick Pier Trust
  • London Corinthian Sailing Club,
  • London Sustainability Exchange,
  • London Youth Rowing,
  • London Wildlife Trust,
  • Mammal Society,
  • Marine Conservation Society,
  • National Association of Boat Owners,
  • Putney Bridge Canoe Club,
  • River Thames Society,
  • Royal Society for the Protection of Birds,
  • Rowers Against Sewage,
  • Salmon & Trout Association,
  • Thames21,
  • Thames Anglers Conservancy,
  • Thames Rivers Restoration Trust,
  • Wildfowl and Wetlands Trust
  • WWF

The Portland experience (presentation available in full on request)
in 1990, Portland’s CSO’s caused:

  • Poor water quality
  • Breached standards for bacteria
  • Threats of legal action
  • Outfall litter

The Portland CSO Control Program was approved by the state of Oregon in 1995. The total project costs, including two major interceptor tunnels, exceeded $1.4 billion. It included three specific projects:

  1. Green infrastructure ‘Cornerstone’ measures to separate rainwater from the sewage system and store it
  2. New pumping and treatment works on the Columbia Slough and Willamette rivers
  3. Deep tunnel storage and conveyance

The Water Framework Directive
The UK is currently at risk of being heavily fined for failing to meet its commitments under the Water Framework Directive set by the EU, due to the on-going sewage pollution of the River Thames. The Thames Tunnel will help the UK meet these commitments, and ensure continued compliance with the urban waste water treatment directive, thereby avoiding unlimited EU fines. 

Media contact: Emily Braham: 07827 352 675
or Tim Webb:  07921 740 753