Analysis of the Impact of the Yangtze-Huai River Diversion Project on the Hydrodynamics and Water Quality of the Xi and Zhao Rivers

The water quality of the Xi and Zhao Rivers, one of the critical lines of the Yangtze-Huai River Diversion Project, not only influences the water quality of Chaohu Lake but also the implementation of the overall diversion project. In order to build a hydrodynamic water quality model of the Xi and Zhao Rivers based on the MIKE11 model, a total of four water quality indicators-chemical oxygen demand (COD), permanganate index (COD Mn ), ammoniacal nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP)-were used Eight working conditions were designed in accordance with the water quality and diversion flow of the Yangtze River, and the model was used to predict the effect of those working conditions on the hydrological situation of the Xi and Zhao Rivers in the planning year. This was based on the low-flow-year dual-lane design diversion scheme of the Yangtze-Huai River Diversion Project. According to the prediction results, the Xi and Zhao Rivers' flow velocity will change significantly after the river diversion project, and depending on the specific diversion flows, the river's water quality will improve to varying degrees. The Rivers' COD, COD Mn , NH3-N, and TP levels will also be able to meet the diversion's requirements.