Continuous Simulation and Other Advanced Modelling Techniques to Size Storage Tanks for a Major Program of Capital Works in the North West of England

In February 1998 the Environment Agency (EA) instructed North West Water Ltd (NWWL) to carry out a programme of works to meet a new, demanding discharge consent standard (average of 3 spills per bathing season per outfall) at specific coastal discharge points. NWWL instigated one of the most ambitious, fast track engineering design/construction programmes witnessed within the UK water industry. A programme costing over $105M (£70M) had to be designed, approved by the regulator, procured, built, and commissioned in a period of 15 months. A joint research project between NWWL, Water Research Centre (WRc) and others was reaching a successful conclusion at this time. This concluded that when designing large storage volumes, follow-on storms were of such critical importance that conventional (single event) modelling techniques are rendered inappropriate. Therefore, Continuous Simulation was the only valid way of confidently establishing the additional storage volumes required to meet the new consents. This paper outlines the hydraulic modelling requirements of this programme of works and details how these advanced modelling techniques were applied in particular to the Fylde Coast area that includes Blackpool, the largest holiday resort in Europe.