Study on Multi-Objective Operation Strategy for Multi-Reservoirs in Small-Scale Watershed Considering Ecological Flows

Abstract

The operation of multi-reservoir system has significantly influence on ecological system in riverine by altering natural streamflow. To alleviate the negative impacts on the ecosystem in a small-scale watershed, ecological flow requirements (EFRs) are incorporated in the operating strategies to tradeoff between the existing human needs and EFRs. In this study, three scenarios of EFRs are firstly generated to study the impacts on the operation efficiency of the existing objectives. Then, the reservoirs are classified into three categories, and the operation strategies are defined, respectively. Finally, the operation strategies are optimized using NSGA-II algorithm and used to simulate the operation processes. The simulation results indicate that the operation objectives between the EFRs and agricultural irrigation have a significant competitive relationship, and the guarantee rate for agricultural irrigation decreases with the EFRs increasing. The reservoirs in the third category with large storage capacity have strong regulation ability for the EFRs, however the reservoir operations in other categories are more vulnerable in term of guarantee rate for irrigation.