Thoughts on coordinated determination and collaborative regulation of ecological flow for water projects in Changjiang River Basin

Strengthening the management of ecological flow release and dispatch from water projects is crucial for maintaining river and lake health and promoting harmonious coexistence between humans and nature. The Changjiang River Basin hosts numerous water projects, such as reservoirs and hydropower stations, where ecological flow management faces challenges including inconsistent target requirements, poor coordination between upstream and downstream reaches, and inadequate ecological flow guarantees during ecologically sensitive periods. Considering the region′s abundant but unevenly distributed water resources and the multi-functional nature of water projects, this study investigates the sources, composition, and satisfaction rate of ecological flow targets at key control sections in the basin. It further identifies major issues in ecological flow assurance. Based on different project types, such as single projects with existing ecological flow targets, those without ecological flow targets, and cascading projects along river reaches, the study proposes principles and requirements for the coordinated determination of ecological flows. Moreover, a systematic approach for collaborative regulation and protection of ecological flows is developed, including multi-objective reservoir operations based on a "simulation-analysis-optimization" framework, optimized daily operational scheduling, ecological dispatch trials during sensitive periods, rigid control of water withdrawal and consumption, and retrofitting of discharge facilities. The results provide technical support for refined ecological flow management of hydraulic projects and basin-wide ecological conservation under the Changjiang River Protection Strategy, thereby contributing to the implementation of the strategy for ecological civilization construction.