采用Mann-Kendall法和线性回归分析方法对汉江上游降水及丹江口水库天然入库径流变化趋势进行了分析，结果均表明汉江上游降水和丹江口水库天然入库径流在1991年发生突变，1991年后汉江水量由丰变枯；但年降水与径流的长期变化趋势均不显著，即汉江流域20世纪90年代持续枯水事件只是其径流丰枯交替的一个枯水期。依据预测的2030水平年汉江上游地区耗水量，分析了丹江口水库入库径流，结果表明，丹江口水库2030水平年入库径流为356.3亿m³ ，仍有向外供水的能力。

As the water source of mid - route of the South - North Water Transfer Project, the changing tendency of the inflow of Danjiangkou Reservoir has very great effect on the construction, operation and management of the project. The Mann - Kendall method and linear - regression method are used to analyze the changing tendency of the precipitation over the upstream of Hanjiang River and the crude inflow of the Danjiangkou Reservoir. The calculated results show that there is a mutation from ample flow to low water in 1991 for both the precipitation and the crude inflow, but the long - term changing tendency of both the precipitation and the crude inflow is not distinct, namely, the phenomena of durative low water in 1990s just was a low water period of ample - dry water alternation in the Hanjiang River catchment. On the based of the predicted water consumption overall the upstream, the inflow of Danjiangkou Reservoir is about 356.3×108 m³ in 2030, it means that the Danjiangkou Reservoir still will have the capacity to provide water for north China.