Studyof Water Resources Carrying Capacity In Karst Area Based On System Dynamics Model

Water is an important factor of affecting social and economic sustainable development. With rapid population growing and economy developing,the demand for water resources increases.And then water shortage has been a global resourcesissues. How touse water resources rationally, and how to coordinate the relationship between society, economy, environment and water resources,those two problems shouldhave been solved soon.In this paper, after reading the literaturesabout water resources carrying capacity, it firstly redefines the concept of water resources carrying capacity, secondly reviews indexes of water resources system, and finally discusses a variety of research methods. According to the Zunyi City’s status, it uses system dynamics method to build model.The model can simulate and forecast future water resources carrying capacity, combining with the social, economic,environmental, water resources.In this paper, using the Vensim software to test the model’s sensitivity, the results prove that the model is feasible. According to the results oftest, it finally choosesurbanization rate, urban domestic water quotas, the growth rate of industrial GDP, 10000 yuan of industrial GDP water consumption, the reusing rate of industrial water, the coefficient of irrigation water utilization, irrigation water quotas, the coefficient of industrialwater discharge, the coefficientof sewage water discharge, wastewater reuse rate as decision indexes. Then it designs five projects, including original, growth, water-saving, environment-friendly, comprehensive. By changing the values of parameters in different projects,it analyses and evaluates water resources carrying capacity under different projects.The results show: in original type, from year 2005 to 2030 the water resources carrying capacity has deteriorated, the degree of water shortage is 0.5114 in 2030; in growthtype, with the rapid development of industrial, from year 2005 to 2030 theindustrial GDP increases nearly 10 times, which leads to the shortage of water resources, the degree of water shortage is amounted to 0.7421 in 2030;in water-saving type, Zunyi City’s water resources carrying capacity has beenin good condition, the degree of water shortage isjust 0.1423 in 2030;in environmental type,from year2005 to 2030 the amount of wastewater treatment and reuse increases gradually, which also supplys the total water,and the degree of water shortage is 0.5030 in 2030; in comprehensive type, the industrial GDP is 1.31249 trillion yuan in 2030, while the degree of water shortageis only 0.3193. By comparison, the comprehensive type is the optimal type.In this paper, it concludesthe causes of deterioration of Zunyi’s water resources carrying capacity and puts improvement measures. To improve water resources carrying capacity of Zunyi City, it needs to invest greater efforts in water conservation, pollution control, adjusting the industrial structure, protecting the water environment and the other aspects.