大型灌区灌溉用水有效利用系数比较分析

从纵向和横向两个角度对比分析大型灌区节水改造对灌溉用水有效利用系数的影响。在横向上，跟踪和调研分析实施大型灌区续建配套和节水改造以来。6个典型大型灌区节水改造实施情况和灌溉用水有效利用系数变化情况，比较研究了灌溉用水有效利用系数提高的规律；在纵向上，以宁夏青铜峡灌区和卫宁灌区为例，详细分析了1991—2007年灌区灌溉用水有效利用系数变化过程，剖析了主要影响因素．最后提出了提高大型灌区灌溉用水有效利用系数的对策措施。

Comparison of effective utilization coefficient of irrigated water in large irrigation districts

The impact of water-saving rehabilitation of large irrigation districts from two respects of vertical and horizontal on the effective utilization coefficient of iriigated water is assessed, on the basis of examining its role in safeguarding food security, farmers＇ income increase, rural economic development and improvement of regional ecological environment. From vertical point of view, rehabilitation cost and coefficient changes of six typical irrigation districts are compared for obtaining the rule of increasing effective utilization coefficient of irrigated water by conducting survey and investigations. From horizontal point of view, the Qingtongxia and Weining irrigation districts are selected as typical cases for examining the impact of rehabilitation on the effective utilization coefficient of irrigated water in the period of 1991-2007. Measures for improving effective utilization coefficient of irrigated water in large irrigation district are put forward.