不同环节灌溉用水效率及节水潜力分析

Analysis of irrigation efficiency and water saving potential at different scales

以漳河灌区为例,在对灌区渠系进行等效概化的基础上,采用经验公式法进行不同工况下不同环节灌溉用水效率的分析计算。结果表明总干及干渠环节和分、斗、农渠环节的渠道水利用系数较大,而支干、分干和支渠环节的渠道水利用系数偏小,渠道断面大小、长度及防渗率是导致渠道水利用系数差异的主要原因。计算分析了不同条件下的灌溉用水效率阈值,达到相应阈值时的投资,以及净节水量和节水率,分析了投资与灌溉用水效率阈值及节水率的关系。表明随投资的增加灌溉用水效率及节水率均提高,但其过程符合报酬递减规律,且节水率的报酬递减速度更快。

Based on a predigested but equivalent canal system for the Zhanghe Irrigation District, using an empirical formula, the irrigation efficiency (IE) in the system is calculated at different scales under different conditions. The result shows IEs are found to be higher at the primary and trunk canals than that of at the sub-main and branch canals. These IE differences are mainly due to the differences in the canal cross section and length, as well as the lining ratio. We calculate the maximum irrigation efficiency (MIE) and its corresponding cost, as well as the water saving potential and ratio under different conditions. An input-output analysis of the relationships between the cost and MIE as well as the water saving ratio is conducted. It shows that both MIE and the water saving ratio are proportional to the cost, but comply the rule of decreasing rewards during the course of the input-output process. The deceleration rate of the water saving ratio would be greater than that of MIE.