Impounding reservoir spillways and energy dissipators: hydraulic design challenges and lessons learnt

Abstract

The hydraulic design of impounding reservoir spillways and energy dissipators could have a significant impact on the safety and economy of these projects. Therefore, gaining an insight into the challenges faced by the hydraulic engineers and how these could be efficiently addressed becomes a matter of particular importance in ensuring the overall project success. During the fifth ‘Asset Management Plan’ United Utilities gained design experience in upgrading the overflow capacities on seven impounding reservoirs in the North West of England which provided valuable information in this respect. Besides the review of some existing design guidance and practices, critical analysis of these has been carried out based on the evidence provided by the extensive physical model testing. In addition, the processes of development and optimisation of the hydraulic design revealed some specific challenges and identified an important requirement for the role played by hydraulic engineers.