Study Of Water Resources System Dynamics Model In Tianjin City

With the rapid development in the economic and social progress, the problems of water resources had become restraints and "bottle neck" against the sustainable development of the national economy and social progress. How to properly handle the relations between water resources and soil population as well as between environment and sustainable economic development had become a focus of social concern. Under the nonlinear and from system structure, the sustainable development model had been established in four sub-models with the consideration of population, economics, water resources and environment. Based on the model, we simulated the progress of water resources system in the future. The assessment index system of water resources sustainzble utilization was set up to select the better plan from five schemes and some suggestions were proposed to realize the sustainable utilization of water resources.Firstly, the present status of water resource and water environment in Tianjin was investigated in detail. Based on this, the main problems in the water exploitation are summarized.Secondly, based on the simulation tool Vensim, the water resource System Dynamics model was set up after system analysis to simulate the progress of the water resources system and predict the instance of water supply and demand.Thirdly, according to the results of sensitivity analysis in the water resources SD model, five comparative schemes were designed. The assessment index system of water resources sustainble utilization was set up and the factor weight were confirmed by the method of AHP. Through the analysis and processing of the simulated values, the better scheme which is propitious to the sustaining utilization of water resources was the fifth scheme. The water resources sustaining utilization index value can be improved by 7% comparing with the current status; The ratio of supply and demand can be improved by 23%; The ratio of water pollution will fall by 40%.At last, based on the result, we should increase the degree of saving water and enhance the sewage treatment rate.