Quipolly dam: A case study on customizing Fusegates® design for adverse spillway conditions

The feasibility and performance of the Fusegate (R) system were tested at LPSC's Quipolly dam; a 21m high earthfill dam located on the Werris Creek in the State of New South Wales, Australia. The primary purpose of the rehabilitation works included increasing the water storage capacity of the reservoir by 55% and improving spillway discharge potential to meet the new 1: 100,000 Annual Exceedance Probability (AEP) flood. The challenges of the project, mainly due to the presence of high tailwater levels and highly perturbed approach channel flow conditions at the spillway, required a more detailed analysis in order to optimize the design, reduce the cost of rehabilitation and minimize the risks. A large scale physical model was performed in collaboration with Artelia laboratories (France) to find a customized solution with a non-mechanical spillway control system. The model studies helped to optimize and calibrate the input for the physical model tests. These studies not only benefited the current research and development of the Fusegate r system but also supported the scientific understanding of labyrinth crested weirs including their hydraulic behaviour. This paper discusses the details of these studies including the tailored Fusegate design adopted to minimize risks and costs.