Research Of System Dynamics For Sustainable Utilization Of Water Resources In Tianjin

Water is an essential resource of human existence and social and economic development. The situation of water quantity reduction and quality deterioration in Tianjin is getting more and more serious. The total amount of the city’s water resources is insufficient to meet the demand and the dependence on external water sources is growing. Based on the current situation, by analyzing the characteristics of water utilization, this article established a model of water resources sustainable utilization in Tianjin from2006to2020using Vensim, a system dynamics software. The model has four highly related subsystems including population, economy, ecological environment and water resources. Prediction result is obtained by operating the model, the result shows that total water demand will reach4.093billion m3in2020, the gap between supply and demand of water resources is-762million m3. The percentage of domestic, agriculture, industry, tertiary industry and ecological water demand of total water demand are13%,25%,44%,6%and12%, respectively. Industrial water demand will replace agriculture irrigation water demand to become the largest water demand. By selecting the decision variables and changing their values, the trends of water utilization are simulated separately under five different programs:maintain the status type, water saving type, industrial structure adjustment type, open-source type and comprehensive type. Analyzing their differences to find out the optimal solution is the comprehensive type. Its total water consumption reduced622million m3and total water supply increased156million m3compared with the status type, its water supply can meet the demand. Combined with the simulation results, some advices were proposed:saving water, promoting water-saving appliances and water-saving technologies, raising the price of water, industrial restructuring, increasing the utilization of non-conventional water resources, improving seawater desalination technology and sewage treatment technology, fully utilizing rainwater and strengthening management. It can effectively alleviate the shortage of water and boost the achievement of water resource sustainable utilization. It also has certain reference significance to the other water-shortage cities.