Impact on sediment deposition in the backwater of the Three Gorges Reservoir Area due to changes of the upstream sediment runoff

According to the recent years' measured data about the runoff and sediment discharge from several major hydrological stations on the upper reaches of the Three Gorges Reservoir,we analyze the water and sediment changes and the causes.The results show that the amount of sediment in the main tributaries of the upper reaches,the Jinsha River and Jialing River,reduces significantly,and the combined effect of the intercept by all types of reservoirs,water and soil conservation in the river basin and sand wining in the channel are the main causes,which will have a direct influence on sediment deposition in the backwater area,and the problems arisen on navigation in the backwater area will be shown later.