基于PCA和GRA-TOPSIS相耦合的灌区用水效率评价模型构建与应用

Coupling PCA and GRA-TOPSIS to Evaluate Water Use Efficiency of Irrigation Districts

【目的】对灌区用水效率进行科学合理的综合评价,为灌区改造建设提供决策依据。【方法】从灌区用水水平、工程状况、管理水平和灌溉技术水平等方面建立了评价指标体系,在此基础上,构建了PCA和GRA-TOPSIS相耦合综合评价模型,以内蒙古引黄灌区5个大型灌区为例进行验证。【结果】PCA和GRA-TOPSIS相耦合法与GRA-TOPSIS法对各评价灌区的综合评价排序完全一致、与FMA法对各评价灌区的综合评价排序位次基本一致,表明评价结果合理;3种评价方法所得评价值的极差分别为0.501、0.448、0.500,变异系数分别为0.699、0.450、0.921,PCA和GRA-TOPSIS相耦合法所得评价值的变异系数比其他2种方法大,更有利于直观地区分各灌区的灌溉用水效率水平,更适宜用于灌区灌溉用水效率等级划分;PCA与GRA-TOPSIS相耦合法所得各评价灌区综合评价值符合灌区实际,评价结果可靠。【结论】PCA与GRA-TOPSIS相耦合评价法适宜于灌区用水效率的综合评价。

【Background and objective】Water scarcity in arid areas in northern China is a bottleneck holding their socioeconomic development.Since agricultural irrigation is a major water user in these areas,improving irrigation water use efficiency is essential to ameliorating water shortage,an fundamental issue in which is evaluation of agricultural water use efficiency.This paper is to present a new method to evaluate water use efficiency in irrigation districts.【Method】The method is based on the principle component analysis(PCA)and grey relation analysis(GRA)evaluation index system;it considered water use level,current situation of engineering projects,management level and irrigation technologies in irrigation district.An comprehensive evaluation model coupling PCA,GRA and the technique for order preference by similarity to ideal solution(TOPSIS)was derived to evaluate water use efficiency in five large irrigation districts in Inner Mongolia that rely on Yellow river for irrigation.【Result】The ranking of water use efficiency obtained from the coupled PCA and GRA-TOPSIS was the same as that calculated from GRA-TOPSIS for all five irrigation districts.It was also consistent with that calculated from the fuzzy matter element analysis(FMA),indicating that the coupled PCA and GRA-TOPSIS is reliable and accurate to evaluate water use efficiency in irrigation districts.The extreme difference of the coupled PCA and GRA-TOPSIS,the GRA-TOPSIS and the FMA method was 0.501,0.448 and 0.500,respectively,with their associated coefficients of variation being 0.699,0.450,0.921,respectively.The large coefficient of variation of the coupled PCA and GRA-TOPSIS makes it more effective to differentiate the water use efficiency between irrigation districts.Overall,results obtained from the coupled PCA and GRA-TOPSIS model accurately described the water use situation in all irrigation districts and the model is hence reliable.【Conclusion】Coupling PCA and GRA-TOPSIS model improved evaluation accuracy of agricultural water use efficiency in irrigation district.