COMPARISON OF METHODS FOR YIELD ASSESSMENT OF MULTIPLE RESERVOIR SYSTEMS

This paper compares four different methods for estimating the yield of a multiple reservoir system. These include simulation, a combined sim ulation-optimization model (WATHNET), a full optimization model, and a simplified optimization model called the yield model. Simulation is u sed widely in practice and provides a good approximation of the behavi or of the system but requires a set of operating rules to be specified , The optimization methods automatically determine operating rules and are therefore quite useful in estimating the yield of a new system th at has not yet been operated. The four methods are used to estimate th e safe historical yield of the Canberra water supply system (Australia ). It was found that the full optimization model and the yield model p rovide high estimates of the system yield because they assume perfect knowledge of future inflows. WATHNET presents a reasonable compromise in estimating the system yield using implied operating rules that are achievable in practice.