中文摘要：

三峡工程的运行对鄱阳湖防洪形势存在潜在影响。以三峡-鄱阳湖系统为典型,采用基于copula理论的多维联合分布函数,建立三峡工程运行前长江-鄱阳湖-＂五河＂（赣江、抚河、信江、饶河、修河）系统中水文要素之间的联合概率分布及条件概率分布,并假设该条件分布关系在三峡工程运行前后保持不变;估计三峡工程运行后长江水文要素的概率分布,结合前面的条件概率分布,可以得到三峡工程运行后研究变量的概率分布;对比分析前后概率分布的变化,即可从统计角度评价三峡水库运行对鄱阳湖水文情势的影响。研究表明：三峡工程运行对鄱阳湖水位有一定影响;5、6月份三峡预泄,将增高鄱阳湖水位,其中,平均水位的增幅大于最高水位增幅,低水增幅大于高水增幅;三峡预泄影响下,湖区圩堤堤前水位没有超过原有堤防设计水位,没有降低湖区圩堤的防洪标准。

英文摘要：

The operation of the Three Gorges Reservoir （TGR） could potentially affect the flow regime in the Poyang Lake and its adopted flood control plan. In this paper, the theory of copula function is used to establish the joint prob- ability distribution functions for hydrological variables in the ＂Yangtze River-Poyang Lake-five rivers＂ system without considering the TGR operation. These conditional probability distribution functions are then derived. It is assumed that the conditional distribution function remains unchanged in the system after the TGR operation. The new probabili- ty distribution functions for hydrological variables can be obtained after the TGR operation through analyzing the proba- bility distribution function of discharges of the Yangtze River after the TGR operation and combining the new discharge probability distribution function with the previously established conditional probability distribution. The difference in the probability distribution functions before and after the TGR operation can be seen as the TGR impact on the flood control in the Poyang Lake. Results show that the pre-releases from the TGR in May and June will increase the water level of the Poyang Lake. The increase in average water level will be greater than that of the maximum water level, and the low water increase will be greater than that of the high water. Under the influence of the TGR operation, the water level is unlikely to exceed the currently adopted design value. Thus, the flood protection standard of the em- bankments for the Poyang Lake will remain unchanged after the TGR operation.