Simulation of the anoxic effect of ecological regulation on Guanting Reservoir

Water transfer is an effective approach to improve water quality in reservoir area. However, the research focusing on optimum efficiency of water transfer is limited, especially the dissolved oxygen (DO) in reservoir area. As a case study of Guangting reservoir (GTR) in Beijing City, the three-dimensional DO model was built based on environment fluid dynamic code (EFDC). And the spatial and temporal distributions of DO concentration with and without ecological regulation were analysed. The results show that both water transfer and ecological discharge will disturb the "oxycline" of the water body, while the effect on the surface DO is not obvious, ranging from -4.65% to 7.28%, but it has a significant impact on increasing oxygen in the bottom layer. The DO concentration in the bottom water increased by 1.85-8.52 mg/L when the output ecological discharge was used in the reservoir, and the oxygen enrichment effect of bottom water was more obvious when considering water transfer and ecological discharge simultaneously, with an increase of 2.71-12.83 mg/L. this study has the guiding significance to improve the dissolved oxygen in the bottom water of GTR area, and can also provide a method reference in evaluating the DO variation driven by the upstream water transfer or ecological discharge similar reservoirs.