【摘要】 以本文第Ⅰ部份提出的灌区分布式水文模型为工具,对典型灌区进行灌区小流域和区域尺度的水平衡模拟,定量分析了不同水管理措施对灌区小流域尺度水量平衡评价指标的影响,以及不同尺度间水量平衡评价指标的变化特点。结果表明:适当增加稻田最大蓄水深度可以减少出流水量损失,使更多的降雨和灌水转化为土壤水,满足水稻的蒸发蒸腾耗水;现状条件下适当减少渠道供水量不会导致水稻产量明显降低,但通过减少渠道灌溉水的投入,可以提高灌溉水分生产率;提高塘堰汇集回归水能力后,塘堰可供水量增加,此时减少渠道供水量不会导致水稻明显减产。输水、配水渠道水利用系数增减5%对灌区水量平衡评价指标没有显著的影响,说明企图通过提高渠系水利用系数来提高区域尺度灌溉水利用效率及节水的潜力有限。此外,灌溉水分生产率随尺度的增大而增加,证明尺度愈大对回归水的重复利用率愈高。更多还原

【Abstract】 The distributed hydrological model for irrigation area based on SWAT proposed by the authors in part Ⅰ of this paper is applied to simulate the water balance at small watershed scale and regional scale in the Zhanghe River irrigation system.The water accounting methodology and related indicators developed by the International Water Management Institute(IWMI) are applied to evaluate the effect of different water resources management strategies on water budget as well as the comparison of indicators on two different spatial scales.The results show that proper increase of the maximum retaining water depth in paddy field can reduce the loss of irrigation water and store and convert more irrigation water and rainfall into soil to fulfill the water consumption of crop evapotranspiration.Under the current condition,a proper reduction in canal water supply will not reduce rice yield,and consequently increase the irrigation water productivity.The ponds water supply capacity will be improved when the capacity of pond’s interception of return flow increases.Then,properly reducing the canal water supply and combining with much more ponds supply,the rice yield will not reduce.There is no significant difference of water balance assessment indictors when water efficiency of canal system varies within(±5%.) The irrigation water productivity increases following the increase of spatial scale,it demonstrates that the recapture and reuse efficiency of returning flow increases with the magnitude of scale.更多还原