10 Years Experience of CSO Management in the United Kingdom

The United Kingdom's ageing sewerage infrastructure meant that by the late 20th century the country was facing a major environmental problem associated with storm sewage discharges from more than 8,000 unsatisfactory combined sewer overflows (CSOs). Addressing this problem presented a major challenge to the UK water industry, but it is a challenge that has been met by a combination of farsighted measures which have included both reorganisation of the institutional arrangements of the industry and the development of sophisticated and integrated planning and management tools. As a consequence, the UK is now nearing the end of a multi-billion dollar investment programme which will see the end of the CSO problem in terms of both visual and water quality issues.The paper reviews the key steps that have brought this about over the last decade and highlights the changes in approach that the industry and water professionals have had to make to allow it to happen. Finally, the paper considers the extent to which the lessons learnt could be applied beyond the UK and, in particular, in the U.S.