Safety Assessment Of Water Resources Utilization In Manas River Basin Under Water Saving Conditions

Manas River Basin is located in the arid area of Northwest China,the middle part of the northern slope of Tianshan Mountains and the southern margin of the Junggar Basin.It is a representative inland river basin with serious shortage of water resources.Since the reform and opening up,the economy of the basin has developed rapidly,and the exploitation and utilization of water resources has been increasing day by day.Due to various natural and human reasons factors,the security of water resources utilization is very prominent.Manas River Basin,as the birthplace of water-saving technology of drip irrigation under mulch in China,has become the fourth largest irrigation agricultural area in China and the largest oasis farming area in Xinjiang after more than 20 years of popularization and application of water-saving technology.Agricultural irrigation water accounts for a large proportion of water resources utilization in Manas River Basin.Promoting water-saving technology effectively improves the efficiency of water resources utilization.However,with the increase of cultivated land area in Manas River Basin,water resources have been overexploited and groundwater has been overexploited,which has caused a series of water resources problems,which seriously threaten the ecological environment and human survival in the basin.Aiming at the existing problems,this paper evaluates the safety of water resources utilization in Manas River Basin under water-saving conditions,analyses the general situation of water resources utilization in Manas River Basin and recent years,and establishes a pressure state response(PSR)model based on the current situation.The safety of water resources utilization in Manas River Basin is evaluated by using the method of fuzzy comprehensive evaluation and approaching ideal point.According to the evaluation results,the existing problems in the process of water resources utilization are summarized,and the corresponding countermeasures are put forward.This paper mainly includes the following aspects:(1)The general situation and current situation of Manas River Basin are introduced and analyzed.According to the development and utilization process of water resources in Manas River Basin,the influence of water saving measures on the development and utilization of surface water and groundwater in Manas River Basin was analyzed.Under the condition of vigorously promoting water-saving measures,the utilization rate of water resources has been greatly improved.Through the analysis of water use structure in the basin,it is found that with the increase of arable land area,the proportion of agricultural water use has been maintained at more than 94%,while the proportion of ecological water use has not increased significantly to more than 1%,but the available water use has been declining.At present,there are many water resources problems in the basin.(2)Establishing a model of Pressure-State-Response(PSR)evaluation index system for water resources utilization safety in Manas River Basin under water-saving conditions.According to the principle of establishing evaluation index system and referring to the model indexes of previous studies,20 evaluation indexes are selected from three aspects of water resources,social economy and ecological environment,and divided into three sub-systems of pressure P,state S and response R.Unification.Analytic hierarchy process is used to calculate the weights of each subsystem,and the entropy method is used to calculate the weights of each evaluation index.Finally,combined with the results of the two weights,the total weights of each index are obtained.(3)Referring to relevant international and national standards and previous research standards,combined with the typical characteristics of Manas River Basin,the evaluation index scoring criteria are determined.The final score was obtained by using the method of fuzzy comprehensive evaluation: the comprehensive scores of the total system from 1990 to 2015 were 2.1396,2.3377,2.638,2.9126,3.4132 and 3.8618,respectively.The final score was obtained by using the method of approaching ideal point: the comprehensive scores of the total system from 1990 to 2015 were 0.2036,0.2793,0.4538,0.5929,0.7406 and 0.7873,respectively.The final overall evaluation results of the two methods are roughly the same,and the scoring trend of the total system is also relatively consistent.(4)Based on the analysis of the results of water resources utilization safety assessment under water saving conditions in Manas River Basin,it is found that the ecological and social benefits of the basin are gradually improved under the situation of vigorous promotion of water saving measures,but the water resources and phosphorus resources are still in serious shortage.The contradiction between supply and demand is prominent.Industrial and agricultural water use occupies ecological water,the water use structure is unreasonable,the effective utilization efficiency of water resources is low,and the potential of water pollution is great.Because of the serious threat,the ecological environment of the basin is worrying.In view of the above problems,some countermeasures are put forward,such as improving the utilization efficiency of water resources,vigorously developing water-saving irrigation technology,paying attention to the optimal allocation of water resources,rationally utilizing non-traditional water sources,and preventing and controlling water pollution.Strengthen the propaganda and construction of the legal system.