基于SWAT模型的五化灌区灌溉用水效率评价

Evaluation of irrigation water efficiency based on SWAT model for Wuhua Irrigation Zone

南宁市五化灌区是广西典型的平原代表灌区。通过构建五化灌区SWAT(Soil and Water Assessment Tool)分布式农业水文模型,探究其在灌区水管理措施下的水文循环规律,并对灌区尺度灌溉水均衡及水分生产率进行分析与评价。结果表明,研究区丰水年灌溉量小,枯水年灌溉量大;作物产量沿着主渠道北侧分布向北有减少趋势;该区域降水融雪对土壤水分的补给占主导作用;灌溉水分生产率主要表现为逐渐下降且趋于平稳,且研究区域边界的灌溉水分生产率较大,而研究区域中部的较小;作物水分生产率与总流入水分生产率随时间增长无明显变化,且两者的空间分布与作物产量空间分布相似。

Wuhua Irrigation Zone located in Nanning City is a typical plain irrigation area.A distributed agricultural hydrological SWAT model was established for Wuhua Irrigation Zone to explore the hydrological cycle under the water management,analyze and evaluate the irrigation water balance and water productivity at the irrigation area scale.The results of analysis demonstrate the annual irrigation is lower in wet year and higher in dry year;the crop yield has a decreasing trend from the main channel to north;rainfall and melting snow play a major role in soil water replenishment;the irrigation water productivity gradually declines and tends to be stable,is relative higher at the boundary and lower in the middle area;the crop water productivity and total inflow water productivity have no significant change with time and their spatial distribution are similar with that of crop yield.