An Analysis of the Variation Process and Causes of Water and Sediment to the Three Gorges Reservoir in Recent Years.

The water and sediment fluxes and their composition have changed greatly in the Three Gorges Reservoir (TGR), which has an important influence on the operation of the TGR. Based on the long series of water and sediment data of important control stations to TGR, the changing process and causes of each group of water and sediment to TGR are systematically studied by statistical analysis method. The results show that the inflow runoff of TGR has little change, and the sediment discharge decreases significantly, which is mainly caused by the decrease in sediment transport from Jinsha River after the impoundment of TGR. Annual runoff of components has no obvious changing trend, but the variation of composition of sediment discharge ratio is bigger. Affected by the impoundment of the Xiluolu and Xiangjiaba Reservoir, the sediment from Jinsha River accounted from the biggest to the smallest area after 2013, the sediment from tributary increased, and the Jialing River and Tuojiang River become the main source of the storage of the TGR, and the riverbed of Xiangjiaba to Zhutuo reach changes from silting to scouring, which becomes an important part of the sediment source to TGR at the same time. [ABSTRACT FROM AUTHOR]