Numerical simulation for flow and water quality of diversion channel - The case of Wangyu River

In order to improve water quality and alleviate eutrophication of the Tai Lake, which is the third largest fresh-water lake in China, a Yangtze River water transfer project was initiated in 2002, taking Yangtze River’s water to Tai Lake to dilute and divert pollutants out of the lake. In this study, we set up a two-dimensional numerical model including tributaries to verify the impact of water transfer on the transport of dissolved substances in the lake. Model results have showed that the effect of water transfer on transport processes in the lake is strongly influenced by hydrodynamic conditions, induced inflow and water lever difference of tributaries. The research showed that the existence of tributaries and its pollutants could make the water quality decline in Wangyu River, and the water flow also has a great influence on the concentration distribution of pollutants. Through calculating, it can be concluded that the Wangyu River will be influenced seriously by west bank tributaries’ pollutants when the water flows less than 150 m 3 /s; Wangyu River’s west bank tributaries water level difference has certain influenced on the distribution of pollutants in the river, especially the water quality near the tributaries mouth has been most affected.