中文摘要：

针对现状以及南水北调中线工程不同调水方案下的水文条件，从可利用水资源量和水环境容量两个方面来研究中线调水对汉江下游枯水期水量和水质状况的影响。以人均月可利用水资源量和人均月水环境容量作为评价指标，提出相应的水安全评价方法和评价标准，来定量评价调水前后汉江下游枯水期水安全的变化程度。研究结论认为：各调水方案对汉江下游水量安全的影响程度比水质安全大；调水对枯水期水安全影响较大的月份是12月、1月和2月，而11月、3月则要好一些；现状条件下的水安全评价结果都在“较为安全”级别以上，而各调水方案的实施对汉江下游水安全都有一定影响，其中以方案Ⅱ的影响最大，方案Ⅲ则由于引江济汉补偿工程的兴建，其水安全保障程度要高于其他方案。

英文摘要：

Aim at the hydrology conditions under present situation and different schemes of the middle route of China＇s south-to-north water transfer project,the effect of the project on water quantity and water quality status in lower reaches of Hanjiang River in low water period is researched from two aspects that are available water resources quantity and water environmental capacity. The assessment method and standard of water security, which are used to evaluate the changes of water security degree before and after transferring water, are put forward. The conclusions are that the effect of water transfer on water quantity security is bigger than that on water quality security after the implement of each scheme;December,January and February in each year are the months when there are more effect of water transfer on water security in low water period;the degree of water security in each month of low water period under present situation is above comparative safety level,and the degree of water security will descend after the implement of water transfer schemes, in which the effect of the scheme Ⅱ is the biggest, hut water security degree of the scheme Ⅲ is higher than that of other schemes because of the building of water diversion project from the Yangtze River to Haniiang River.