Multiobjective Reservoir Optimization Considering Sedimentation Applied to the Three Gorges Reservoir

Abstract

Increasing the power generation and reducing the sediment deposition in a reservoir are two contradictory and incommensurable objectives. Hence, these two operational objectives rarely are considered simultaneously in reservoir optimization. This study proposes a method to balance sediment desilting and power generation in reservoirs, and to study their quantitative relationship. First, a formula to calculate the suspended sediment transport rate for reservoirs was established. Second, based on that formula, a multiobjective model was built that considers simultaneously, the sediment transporting efficiency and the power generation efficiency. The nondominated sorting genetic algorithm (NSGA-II) along with Pareto optimality was used to find the Pareto front of the model. The proposed method was applied to the Three Gorges project in China. The research results not only provide the Pareto front of the reservoir operation scheme, but also imply that the maximum annual sediment runoff was improved by 6% at the expense of 9% of the annual power generation.