| With the economy development, the population increase, the accelerations of urbanization and industrialization in Xianyang City, the contradictions between water resoureces supply and its demand increases sharply year by year. Whether the water resource is exploited and used reasonably will affect sustainable development of social economy. The research of water resource carrying capacity may supply the total population and economy scales which the water resource could carry at present year and planning years, and supply the corresponding countermeasures for the water resource exploitation and utilization, and is benefitial to the harmonious developments of water resource and social economy.In this thesis, the total population and economy which the water resources could carry in current year and the planning years of Xianyang was taken as the objectives.The correlativity among the water resource system, social system, economy system and ecology system were analyzed, the corresponding assessment indice system were established, Three models were used for assessing water resource carrying capacities of thirteen counties in Xianyang City. The multi-objective model to calculate The maximum population of the current year and the planning years that the water resource could carry were calculated using multi-objective carrying capacity models. System dynamic model were adopted to analyze the interrelations among water resource sub-system, industrial waters utilization sub-system, agricultural water utilization sub-system, ecological water utilization sub-system and sewage water treatment sub-system. Four schemes for economy development and water resource utilization were designed and simulated. The simulated results were compared for 2015, 2020 and 2025. Main conclusions obtained are as follows:(1)A comprehensive assessment system was established which contained twenty-two assessment indice belong to water resource sub-system, social sub-system, economy sub-system, ecology sub-system, comprehensive coordination sub-system. The standard values of different levels for each index were detenmined. Fuzzy comprehensive assessment method based on degree of membership, projection pursuit classification model, and fuzzy recognition assessment model were used to assess water resource carrying capacity (simplified as WRCC below) of thirteen counties in Xianyang city for current year (2008). Through comparisons and analysis, the results showed that: WRCC for Wugong County was in level 2 which was in good and below- maximum-capacity conditions. WRCC for Yongshou County, Bin County, Changwu County, Liquan County, Jingyang County, Chunhua County, Qian County, Sanyuan County, Xingping County, Qindu zone and Weicheng zone were in level 3, and were beyond the maximum carrying capacity a little. WRCC for Chunhua County was in level 4 and heavily beyond the maximum carrying capacity.(2) Quantitative models were adopted to calculate water resources capacity of 13 counties in Xianyang in current year (2008). Maximum population, which current economic structure and water use leves could carry, were calculated accoding to whole well-off and all well-off living standards. The result showed that: the maximal economy scale, that the WRCC of most counties in Xianyang could carrid under the current economical structure and water use level, was whole well-off living standard, i.e., GDP per person was 10, 000 RMB yuan, and living water using quota was 100 L per person per day.(3)Based on the social-economical data and《Planning of economy development in Xianyang》, the WRCC of Xianyang were analyzed and forecasted for 2015, 2020 and 2025. The results showed that: if Xianyang city develops according to the current economy structure, all counties'RCI(relative capacity index) except Jingyang were larger than 1 except and were over their maximum carrying capacities in 2015.With the increases of available supply of water resoureces, RCI values were smaller than 1 for Sanyuan and Xingping County, but were larger than 1 for the other counties in Xianyang for the year 2020. WRCC situations of the counties in 2025 will be similar to the situations in the 2020. Therefore, with the development of economy, the economical structure of the counties in Xianyang have to be changed, the efficiency coefficient of water resources should be promoted, and then WRCC could be increased in order that the social-economy sustainable development could be realized.(4) WRCC system dynamic models of Xianyang were established based on the social-economy and water utilization data (water use conditions for different trades) from 2005 to 2010, 2010 to 2025 were taken as planning years. By analyses of the current social-economy and water utilization situations in Xianyang, Twelve decision variables such as industrial output increasing rate, field irrigation area increasing rate, and so on, were chosen. Four development schemes (including trend development type, resources and environmental protection type, economical development model and coordinate development type) were designed and used for simulation of WRCC. The results showed that: in the trend development scheme, the industry developed rapidly in Xianyang, its agriculture developed slowly because of agricultal and ecological water use was occupied and in shortage, water shortage degrees ranged from 9% to 35% in severe shortage of water resources. In the resources and environmental protection scheme, ecological environment was protected well, but industry and agriculture development was serious restricted, their output was only half of the first scheme in the planning years. In the economic development scheme, industry developed quickly, but ecological environment was deteriorative, undergrand water resource was severely overdraft, and water shortage still existed, which was about 4%, the development was not continuable. In the coordinate development scheme, industry and agriculture developing speed was kept at speed of 13.8%, treated sewage reusing amount was increased, ecological environment was improved well, the water shortage was 0.4% under the most serious conditions. According to the contrasts and analysis of the four schemes's modeling results, the coordinate development scheme was chosen as the best WRCC sustainably developing scheme in Xianyang. |
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