Analytical analysis for optimal operation of the recipient reservoir in inter-basin water transfer projects

A theoretical analysis framework considering the tradeoff between water supply benefit and water diversion cost is established to deal with real-time operation issues in inter-basin water diversion projects. First, the optimal decisions for the recipient reservoir are discussed. Then, how the forecast information uncertainty may influence the reservoir operation is investigated, and a criterion on forecast information utilization is established based on the acceptable risks of water shortage and spill. Finally, the Biliuhe reservoir in Liaoning Province is taken as an example to verify the analytical framework. The results show that when the water availability amount of the recipient reservoir is small, water diversion could increase both the immediate benefit of water use at the current time step and the potential benefit of water storage at the end of the decision period. At optimality, the marginal benefit of storage equals the marginal benefit of current release, as well as the marginal cost of water diversion. With the increase of the water availability (before water diversion), water is released based on the current water demand, and the increase of water diversion improves only the benefit of water storage. In this case, at optimality, the marginal cost of water diversion is equal to the marginal benefit of water storage. Moreover, when the expected water storage is small, the reservoir has a relatively high probability of water shortage. The utilization of the forecast information depends on the acceptable risk of water shortage. Otherwise, the reservoir has a higher probability of flow spill, and the utilization of the forecast information depends on the acceptable risk of spill.