长江倒灌鄱阳湖原因及发生条件的量化指标

江湖倒灌对鄱阳湖流域水动力变化和流域水环境保护等方面有重要影响,正确认识江湖倒灌原因和倒灌发生条件对明晰江湖倒灌作用机理、研究倒灌强度和倒灌影响范围等方面具有重要意义。在剖析江湖倒灌原因的基础上,从非恒定流洪水波传播的角度出发,结合鄱阳湖为"河相"、"湖相"时江湖倒灌的特点,提出了长江作用强度指标和鄱阳湖作用强度指标,在此基础上引入江湖作用综合强度函数,依据实测资料,分析研究了江湖作用综合强度函数的关系表达式、江湖倒灌发生条件及量化指标。经验证,所提出的江水倒灌量化指标可区分江湖顶托和江湖倒灌现象,可实现对鄱阳湖为"河相"、"湖相"时的江湖倒灌预测,且提高了预测江湖倒灌起止时间、总历时和年内发生次数的准确率,成果可用于江湖关系研究和鄱阳湖流域水资源综合利用工程实践中。

Reverse flow from Yangtze River to Poyang Lake: causes and occurrence conditions quantization index

Reverse flow has an important impact on hydrodynamic changes and water environment protection in Poyang Lake Basin. A correct understanding of the causes and conditions is of significance to clarify the function mechanism of reverse flow and study the intensity and coverage of influence of reverse flow. From the perspective of unsteady flow flood wave propagation,by analyzing the causes of reverse flow,and considering the characteristics of reverse flow when Poyang Lake is in fluviatile facies and in lacustrine facies,this paper puts forward the Yangtze River action intensity index and Poyang Lake action intensity index. On such basis,the comprehensive river-lake action intensity function is introduced. With the measured data,this paper has analyzed and studied the relational expression of the comprehensive river-lake action intensity function,as well as the occurrence conditions and quantization index for reverse flow. It is verified that the proposed reverse flow quantization index can be used to distinguish river-lake uplift and reverse flow phenomena,and predict reverse flow when Poyang Lake is either in fluviatile facies or in lacustrine facies,with improved accuracy rate in predicting the starting time,total duration and annual occurrence times of reverse flow. The results can be used to study river-lake relations and the actual engineering for comprehensive utilization of water resources in Poyang Lake Basin.