农业灌溉节水评价指标与尺度问题

该文探讨了农业灌溉节水的评价指标与尺度问题，指出产生节水灌溉尺度现象的原因是由于灌溉过程中回归水的重复利用。讨论了在不同尺度下的水平衡要素及其在节水尺度效应中的作用；说明随尺度的增大，水平衡过程变得复杂化，节水尺度效应现象也更突出。指出由于尺度效应的存在，传统灌溉效率指标在节水效果评估及水资源调配决策中的局限性，并对近年来国际上提出的相关评价指标进行评述。结合两个实例就评价指标随空间尺度的变化规律及灌区尺度节水策略问题进行了讨论。

Assessment indicators and scales of water saving in agricultural irrigation

The objective of this paper is to explore the assessment indicators and issues of scale effect of irrigation water saving, which caused by the return flows and their reuse in water resource system. The authors analyzed the components of water balance and their roles at different scales, and pointed out that the situation would be becoming more complicated and scale effect could be more and more significant with the increase of scale. The classical concepts of irrigation efficiency, which ignored the existence of scale effect, had limits and constraints in their usefulness in the field of water resource management and assessment, so some new definitions and indicators introduced recently were reviewed. The changing law of assessment indicators with scale and water saving strategies of irrigation district scale were discussed through the analysis and comparison of two cases.