Comprehensive Benefit Evaluation Of Water Resources In Large Scale Irrigation District

Large irrigaton districts play a very important role in food security, promotion of economic development and protection of ecological environment. However, in recent years, with the social and economic development in large scale irrigation districts, some serious problems emerged because of insufficient capital investment, unreasonable exploitation and utilization of water resources and laggard management system. Evaluation of comprehensive benefit of water resources in large scale irrigated areas, can help us know the comprehensive benefits of water resources in irrigated areas, realize the root caurse of existing problems, and provide foundation for sustainable development of irrigation districts.Therefore, this paper studied the comprehensive benefit of water resources in large scale irrigation districts, taking baojixia irrigation district as an example, and evaluated comprehensive benefit of water resources and got some results:(1) Defined the intension of the comprehensive benefit of water resources in large irrigation districts: the integration of social benefit, economic benefit, ecological and environmental benefits. And analyzed the theoretical basis of comprehensive evaluation.(2) According to the problems in actual constructing of index system, proposed a mothod of combination of qualitative and quantitative methods. On the basis of initial index system, used mathematical methods to select the independent and representative indexs.(3) Analyzed and summarized the merit and demerit of methods used to identify weight, this paper selected three methods to determine the index weights: AHP, the method of entropy weight and comprehensive method. This paper made comparative analysis of results of three methods.(4) Applied fuzzy synthesis, projection pursuit model and genetic algorithm combining method to the comprehensive evaluation of water resources.(5) Take baojixia irrigaton district as an example, evaluated the comprehensive benefit of this district. Determined the index system of comprehensive benefits. Index system included three categories and 16 indexs. The results indicated: the four indexs of peasants'income per capita, per capita share of grain, residents' income per capita and GDP per capita, play a relatively important role in comprehensive benefits.The results of comprehensive evaluation show that: comprehensive benefit of baojixia irrigation is improved greatly from year 1991 to 2005.