Optimal Dam Operation during Flood Season Using a Distributed Hydrological Model and a Heuristic Algorithm

A physically based distributed hydrological model is coupled with an optimization algorithm for joint dam operation to reduce the flood peaks downstream. The decision variables are the release-inflow ratios. The heuristic algorithm seeds different release scenarios attempting to find the most suitable combination. The objective is to reduce the flood peak downstream, and the objective function is to minimize the difference between the simulated and threshold discharges. The latter depends on the purpose of flood management at the basin. Here, it is proposed as the mean discharge during heavy rainfall and is used to start a special dam operation. In order to fulfill the objective function, the reservoirs are expected to release water before the flood event takes place and close the gates during the flood peaks to replenish the released water beforehand. The developed system was applied to the upper Tone River in Japan where the optimal release schedule from two key dams was obtained. The observed weather radar products were input to the hydrological model to simulate the discharge within the river network. Then, the simulated inflows were input to the dam storage functions. The release is routed downstream and the river discharge is evaluated at the control point. The results indicate that the proposed integrated operation can effectively reduce a flood peak suggesting the feasibility of real-time operation in future developments.