| Ledu District of Haidong City,Qinghai Province is a dry and water-scarce area in the northwest of China.The district faces a severe situation in terms of concentrated cultivation industry,serious soil erosion,high difficulty of water resources development and fragile ecological environment,and the social and economic development is facing a severe situation.The optimal allocation of water resources in Ledu District is of far-reaching significance to promote the high-quality socioeconomic development of the district.Combined with the characteristics of Ledu District,this disseratation takes 2018 as the current situation year and2025 and 2030 as the planning level years to optimize the allocation of water resources.The main contents and conclusions are as follows:1.Systematic introduction of the basic situation of human geography and social economy in Ledu District of Haidong City.Based on the basic data such as the current situation of water consumption in Ledu District of Haidong City,we analyze the problems existing in the current situation of water resources development in Ledu District.2.Based on the basic data,we predict the socioeconomic development indexes of the district in 2025 and 2030 using the Gray GM(1,1)Model and the Integrated Growth Rate Method.Water supply and demand in 2025 and 2030 are projected in two scenarios: general water conservation and intensive water conservation,and three analyses of water resources balance are conducted.The result of the primary balance analysis shows a water shortage rate of 47.9% in2025 and 53.8% in 2030;the result of the secondary balance analysis shows a reduction in water shortage,16.1% in 2025 and 8.1% in 2030;the result of the tertiary balance analysis shows a water shortage rate of 3.4% in 2025 and 0.0% in 2030.The results of the three analyses of water resources balance show that it is necessary to establish an Allocation Model of Multi-Objective Optimization to optimize the allocation of water resources in Ledu District.3.Taking the maximum comprehensive water use benefit of each industry as the economic goal,the minimum water shortage as the social goal and the minimum sewage discharge as the ecological goal,the parameters,variables and other constraints are determined by 3 water sources and 5 water users.Through the independent optimization of the three objective functions,the objective functions are standardized and weighed by the combined analytic hierarchy process and entropy method.The single-objective problem is transformed into a multi-objective problem by linear weighting method,and the functional expression of the multi-objective optimization model is obtained.In this dissertation,the gamultiobj function in the MATLAB software toolbox is used to solve the problem,and 16 sets of solutions and corresponding conclusions of the 4 objective functions under the two scenarios(general and enhanced)in 2025 and 2030 are obtained:(1)Under the objective of maximum economic benefits of water use,the water shortage is concentrated in agriculture;(2)Under the objective of minimum water shortage rate,the result shows serious water shortages in agriculture;the industrial water use will show a large shortage in 2025;it can meet the requirements of the tertiary industry and ecological water use.(3)Under the objective of minimum ecological pollution discharge,the water shortage rates in 2025 and2030 for domestic,industry,agriculture and tertiary industry are similar,respectively: 5%,20%,25%,and 20%;(4)Under the objective of maximum comprehensive benefits,the ecological water demand can be met by 2025 and 2030.The domestic water demand shows a water shortage rate of 5% under the general water-saving scheme,and the water shortage rates of industry,agriculture and tertiary industry are similar under different water-saving schemes,which are 20%,25% and 20% respectively.4.According to the characteristics of water resources in Ledu District of Haidong City,an evaluation model of water resources allocation effect is established to evaluate the effect of optimal water resources allocation under the objective function of maximum comprehensive benefit.The evaluation model consists of 3 criteria layers and 9 evaluation indexes,forming a hierarchical recursive structure.The comprehensive index method is applied to evaluate the effect of water resources allocation in Ledu District,and the values of the comprehensive index of allocation efficiency in 2025 and 2030 are calculated to be 52.2% and 66.8% respectively.The result shows that the allocation of water resources with the multi-objective model has promoted the socioeconomic development and ecological environmental protection of Ledu District,but further optimization is still needed to improve the efficiency of allocation of water resources. |
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