Abstract:

We analyzed the variation of dominant discharge and sediment-carrying capacity of flow in the downstream of Three Gorges Reservoir before and after the reservoir impoundment. The analysis is mainly based on data observed from Yichang hydrological station, the representative station in the downstream of the dam. We found that the variations of the primary and secondary dominant discharges caused by water storage of the Reservoir as well as the variations of sediment carrying capacity revealed the trend of longitudinal erosion of the riverbed. Moreover, variation of sediment-carrying capacity before and after the impoundment in the presence of equal flow explained the facts of medium and low flow erosion, medium and low water level, as well as the riverbed variation controlled by nodes.

Key words: dominant discharge, sediment-carrying capacity of flow, water storage of Three Gorges Reservoir, erosion, water level