Modeling competitive-cooperative relationship between flood control and hydropower generation within hierarchical gaming structure of reservoir operation

Abstract

Quantifying the relationship between flood control and hydropower generation in reservoir operation optimization is challenged by both institutional barriers and ill-posedness. Different stakeholders fit within hierarchical institutional structures and parameter equifinality may exist. Compared to the assumption of centralized decision-making and only one optimal solution used in previous studies, this paper investigated the effects of ill-posedness on the competitive-cooperative relationship between flood control and hydropower generation within a hierarchical gaming process. Based on the ill-posed bilevel programming model for the Three Gorges Reservoir pre-impoundment problem, this study revealed that the ranges of potential flood risk and hydropower generation (i.e., competition space between two objectives) could be narrowed, with the increased minimum of hydropower generation and increased minimal occupancy rate of flood control storage. Importantly, different from the “as one falls, another rises” relationship implied by Pareto front solutions, cooperation of the water conservation department with the flood control department, namely selecting a refill rule curve in favor of flood safety, could reduce the flood control risk without sacrificing power generation benefits. Furthermore, a higher cooperation degree would decrease the efficiency loss related to hydropower generation without changing potential flood risk.