Research on Characteristics of Sediment in Yichang-Wuhan Reach after Impoundment of the Three Gorges

Abstract

Reservoir regulation make conditions of sediment under the dam change greatly after impoundment of the Three Gorges Project. This paper analyzes change trend and abrupt change situation of incoming sediment and studies characteristics of new sediment of Yichang and Hankou Stations after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method. The result indicates that after operation of the Three Gorges Reservoir, annual sediment runoff changed suddenly and sediment runoff reduced sharply in Yichang and Hankou Stations; sediment entering the Yichang-Wuhan reach decreases substantially and it almost can be regarded as clean water discharge. Research shows unsaturated degree of the clear water released from reservoirs decreased after obtaining sediment along the river, so the sediment discharge would be partly recovered.