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

Reservoir regulation make conditions of flow under the dam change greatly after impoundment of the Three Gorges Project. This paper analyzes change trend and abrupt change situation of incoming water and studies characteristics of new flow of Yichang and Hankou Stations after impoundment of the Three Gorges with Mann-Kendall nonparametric rank test method. The result indicates that operation of the Three Gorges Reservoir has leveled runoff process and shortened dry season and extended median water period; After operation of the Three Gorges Reservoir, monthly river runoff of several months in both of Yichang and Hankou Stations changed abruptly. However, so far as time of abrupt change is concerned, sudden change of annual river runoff or monthly river runoff has little to do with operation of the Three Gorges Project.