Relationship between water level and discharge of dam vicinity downstream Three Gorges Reservoir after its impoundment

The relationship between water level and discharge of the dam vicinity(which is from Yichang to Shashi) downstream Three Gorges Reservoir,has great influence on the navigation in the reach.Firstly,the field data of three hydrological stations in the reach are analyzed.The results indicate the difference between the hydrological stations-in Yichang and Zhicheng,the relationship between water level and discharge varied little in dry season,and declined in wet season,while in Shashi that is reversal.Secondly,analysis of causes of the difference is made from three aspects,including scouring and deposition of the riverbed,variation of the erosion basis of the reach and the riverbed resistance;and the main factor that influence the relationship is found.At last,the change trend of relationship between water level and discharge at the dam vicinity is predicted.