Abstract:

By the methods of field data analysis and numerical model computation for the river network of the Jingjiang River and Dongting Lake,this paper analyzed the watersediment transportation and erosiondeposition changing in Dongting Lake after the Three Gorges Project (TGP),and predicted the impact on the water level in Dongting Lake.The main results show that at the end of the fifty year’s operation of the Three Georges Project,the annual average runoff and the annual average sediment discharge of three diversions in the Jingjiang River will be less 43 percent and 73 percent than long term average value;after the operation of TGP,the flow and sediment diversion from Jingjiang reach of the Changjiang River to Dongting Lake will continue to decrease and the deposition in Dongting Lake will reduce greatly,which is much useful to prolong the lake’s life.Because of the influence of the scheduling of TGP and the erosion of Jingjiang river reach,the water level decreasing in flood season is useful to flood prevention,but is harmful to the ecological environment in dry season,especially in storage period of TGP.