首先对三峡蓄水后近坝段内3个水文站实测水位流量资料进行了整理和分析,分析表明3站中枯水水位流量关系变化不同,蓄水后宜昌和枝城枯水水位流量关系变化基本不变,中水水位流量关系有所下降,而沙市枯水水位流量关系有所下降,中水水位流量关系基本不变.然后从河床冲淤、河道侵蚀基准点条件和河道阻力变化3个方面分析了3站水位流量关系变化产生差异的原因,并指出河道侵蚀基点条件是影响3站水位流量关系的主要因素,最后对近坝段水位流量关系的变化趋势进行了预测.
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.