关键词: 江湖关系;顶托作用;顶托角;三峡水库;鄱阳湖;长江;

Abstract: There are complex riverbed evolution and material-energy exchange in the river-lake confluence system formed by the Changjiang River and Poyang Lake.The complicated converge jacking effect between Changjiang River and Poyang Lake is an important factor determining the water exchange between the river and lake, which influences the water resources, flood control, irrigation, navigation and ecology of the Poyang Lake.We established an index system for assessing the jacking effect strength of Changjiang River and Poyang Lake from the basic equation of momentum, and propose a index of jacking angle(R).The results show that there is no trend change of R since 1980s, indicating that the jacking effect strength of Changjiang River and Poyang Lake has not changed obviously after the storage of Three Gorges Reservoir.However, from the intra-annual variation, the jacking effect strength is obviously enhanced due to the replenishment effect of Three Gorges Reservoir in dry period.On the contrary, the jacking effect strength is weakened due to abatement of the flood peak during the flood season and impoundment at the end of flood season.The change of the jacking effect will cause more water to stay in the lake during April to June, which is prone to basin flooding.While the jacking effect accelerate the lake water into the river during July to October, which makes the low-water level situation of Poyang Lake continue to deteriorate.The research results can provide reference for the governance and protection of the Changjiang River and Poyang Lake.

Key words: river-lake relationship; jacking effect; jacking angle; Three Gorges Reservoir; Poyang Lake; Changjiang River;