Assessing the Role of Foresight on Future Streamflows in Storage-yield-Reliability Analysis of Surface Water Reservoirs

This paper explores the effect of the horizon of foresight on future inflows on the minimum reservoir capacity required for meeting a specified yield. The goal is achieved by formulating the problem as a series of finite-horizon mixed integer linear programs (MILPs), each with a limited, partial foresight on future inflows. The MINLPs are then solved sequentially over a long-run planning horizon for determining the minimum reservoir capacity required for meeting a specified reservoir yield at a certain level of reliability. The results indicate although it is generally true that the required reservoir capacity will increase if the foresight on future inflows becomes more limited, an opposite result is also possible to occur depending on the system's characteristics and hydrology. Moreover, knowing about future inflows does not help any more after a certain level of foresight horizon. These findings provide insight into the issue of uncertainty of future inflows and their forecasts in the design and operation of reservoir systems.