Development of a Long-term, Ecologically Oriented Dam Release Plan for the Lake Baiyangdian Sub-basin, Northern China

Using China’s Lake Baiyangdian sub-basin for a case study, we developed an ecologically oriented dam release plan that can be used to define an optimal dam operation scheme that provides both the environmental flows required by bodies of water and wetlands downstream from the Xidayang Reservoir dam and enough water for agricultural, and industrial water users. In addition, we evaluated the benefits that might be provided by modifying releases of water from the reservoir. To attain ecological sustainability in the sub-basin, we used the supply for each water user as a decision variable based on three objectives: (1) to achieve sustainable socioeconomic development; (2) to keep the water volume as close as possible to the ideal environmental flows in the urban rivers of Baoding City; and (3) to keep the water amount as close as possible to Lake Baiyangdian’s ideal environmental water requirements. We used the ideal-point method to provide dimensionless values for the first objective, and then used a weighting method to integrate the three objectives into a single holistic goal. We then used the GAMS/CONOPT software to solve the nonlinear model and predict the optimal results. We discuss the optimal water allocation and ecologically oriented dam release plans for the three scenarios. To determine the limitations of the method, we performed a sensitivity analysis, and discuss the optimal results for different weightings of objectives provided by decision-makers. The results of the optimization analysis provide a set of effective compromises among the target objectives that can guide future management of water releases from the reservoir.