Adopting depthaveraged method a kε model ina boundaryfitted coordinate system was deduced. Employing both orthogonal staggered mesh and nonorthogonal staggered mesh methods, the water pollution in some river reaches with a large curvature or with tributary entrances can be numerically simulated. Then, the water quality predication for Chongqing stretch of Three Gorges Reservoir may be performed using this model, and the influence ofthe TGPs construction on water environment can be forecasted in time. Some corresponding countermeasures are suggested. The basis for classifying functional waterbody regions of Three Gorges Reservoir is provided. 