Interim measures are discussed within this report [IND01]. Having sorted out policy and political barriers in Philadelphia, there is evidence that BG solutions have an immediate impact on reducing flows into the combined sewer systems and their adoption is quick and grows with time - see vision statement showing some of the alternative schemes being adopted by cities and regions around the world. On a project-by-project basis, these reductions will increase from the current level but all judgments should be based upon the status quo following currently committed projects such as Lee Tunnel and sewage treatment works upgrades.
In-river solutions should be examined as part of a wider fully integrated BG solution for London. Legal arguments aside, this will enable a final assessment on whether there is in fact a need for additional storage provided by a tunnel solution or whether the alternative schemes can fully satisfy future requirements. If alternative schemes cannot, what is the best solution using a combination of the approaches?