Author(s): Chongming Li; Xiaobo Chao; Pingyu Lu; Yafei Jia
Linked Author(s):
Keywords: Hydrodynamics; Pollutant transport; CCHE2D model; Yangtze River; Jialing River; Three Gorges Reservoir
Abstract: Chongqing is one of China's four largest cities and located at the upstream of the Three Gorges Reservoir. The water pollution in Chongqing Reach of the Yangtze River has been considered as one of important issues to be addressed. The geometry of this reach is quite complex, including many meander segments, several small islands, the confluence of Yangtze River and Jialing River, etc. In addition, the operation of Three Gorges Reservoir by rising or dropping the water level may also affect the flow fields and pollutant transport in this reach. In this study, the unsteady flow fields and pollutant transport in Chongqing Reach were simulated using the numerical model CCHE2D, developed at the National Center for Computational Hydroscience and Engineering, the University of Mississippi. The model is a finite element model utilizing a special method based on the collocation approach called the efficient element method. Two cases were simulated for modeling the unsteady processes of water level rising from the natural level to the maximum 175m and water level dropping from 175m to the natural level due to the operation of the Three Gorges Reservoir. More than thirty point sources from local industries, municipal sewages and small tributaries along the Yangtze River and Jialing River were considered as side pollutant loadings in the model. The simulated flow fields were compared with field measurements for model calibration and validation. It can be found from the simulated results that the processes of water level rising and dropping greatly affect the hydrodynamics as well as pollutant transport in Chongqing Reach. This study shows that the numerical model is capable of providing useful information for water quality management in the Yangtze River.
Year: 2013