BECKTON AND CROSSNESS CATCHMENTS SEWERAGE MODELING PROJECT - PLANNINGAND IMPLEMENTATION

An extensive planning period has been a major Factor in the implementa tion of a pound 7.5 million project to build computer models of the se wers of London's Beckton and Crossness sewage treatment works catchmen ts, which serve around five million people in central and east London. The sewer systems are predominantly combined, and heavy rainfall lead s to a level of service deficiencies with a risk of both flooding to p roperty and combined sewage overflows. A feasibility study carried out in 1988 identified several uncertainties which would be encountered i n attempting to model these networks, owing to the size and complexity of the systems. The major risk areas were looked at in detail, and ex isting and new methods were sought worldwide to help the project. By t he end of 1991, it was considered that sewerage modelling expertise ha d advanced far enough to make the project viable. A strategy to use la test proven technology and software wherever possible was agreed, and development programmes were put in place where shortcomings existed. A methodology for modelling was developed which gives stepped progressi on of model building to allow for continuous review and monitoring of progress, cost and risk, Also, the project is subdivided into five mai n areas of work. Progress in each area provides deliverables to Thames Water irrespective of the success of the modelling, The final output of the project will be a data model and results analysis system that c an be used with a variety of numerical analysis tools.