鄱阳湖口水位流量关系研究

Research on the Relationship between Water Level and Discharge at the Poyang Lake Estuary

水文站的水位流量关系变化反映了江湖之间的相互作用,为探究长三峡工程投运后长江与鄱阳湖的相互影响,分析了九江与湖口站的水位流量关系,基于考虑回水顶托作用的水位流量关系,建立了九江、湖口水位流量计算方法。研究表明:三峡工程投运后,九江站水位流量曲线下移,多年平均水位较三峡建库前降低0.8 m,综合线低水位区域也逐年下移,受九江水位降低影响湖口站平均水位降低0.7 m,三峡工程对长江干流的影响范围在大通以上,长江对鄱阳湖的顶托作用减少1.1%;基于前人成果,研究了湖口流量计算方法,2003-2021年资料拟合的计算公式精度达到86%,建立了湖口水位流量关系曲线,提出了湖口倒灌判别关系,当九江与五河流量之差超过30000 m^(3)/s时可能发生长江水倒灌鄱阳湖,研究成果为长江与鄱阳湖顶托关系分析提供了一定借鉴。

The change of the water level discharge relationship of the hydrometric station reflects the interaction between rivers and lakes.In order to explore the interaction between the Yangtze River and Poyang Lake after the operation of the Long Three Gorges Project,the water level and flow relationship between Jiujiang Station and Hukou Station are analyzed.Based on the water level and discharge relationship con⁃sidering the backwater jacking effect,the calculation method of water level and flow in Jiujiang and Hukou is established.The research shows that after the Three Gorges Project is put into operation,the water level and flow curve of Jiujiang Station moves down,the average wa⁃ter level for many years is 0.8 m lower than that before the Three Gorges Reservoir is built.The low water level area of the comprehensive line also moves down year by year,and the average water level of Hukou Station decreases by 0.7 m due to the reduction of Jiujiang water level.The influence range of the Three Gorges Project on the main stream of the Yangtze River is above Datong,and the jacking effect of the Yang⁃tze River on Poyang Lake decreases by 1.1%.Based on previous studies,the calculation method of Hukou flow is proposed.The accuracy of the calculation formula of data fitting from 2003 to 2021 reaches 86%.And the relationship curve of water level and flow is established.The discrimination relationship of lake mouth backflow is proposed.When the difference between the flow of Jiujiang River and the flow of Wuhe River exceeds 30000 m^(3)/s,the Yangtze River water may backflow into Poyang Lake.The research results provide some reference for the analysis of the jacking relationship between the Yangtze River and Poyang Lake.