System Simulation Of The Policy Design And Efficiency For The Water Ecology Carrying Capacity

The contradictions between the supply and demand of the water resources aggravating increasingly and the status of water pollution worsening year by year are the two important problems during the present utilization of water resource in China. Under the guiding of the 11th Five-Year Plan and the construction planning of Poyang Lake Eco-economic Region, Gan river basin, as the chief tributary of the Yangtze river, is especially paying attention to taking the strategic conception of protecting ecology and economic development in the course of development, constructing the ecological demonstration area and a priority area of low carbon in order to realize the coordinated development of economy and society, and harmonious development between man and nature. The research on the water ecology carrying capacity is being carried out under this guiding ideology to solve the comprehensive development and utilization of water resources, and the social, economic, ecological harmonize sustainable development issues.By defining the concept of water ecology carrying capacity, following the two main material flows, that is the water resources supply & consumption and pollutants produced & reduced, this paper built the dominant structure model of the upper limit of the water ecology carrying capacity of Gan river basin and the system dynamics modelⅠof the water ecology carrying capacity of Gan river basin, realizing the static simulation of the upper limit of the water ecology carrying capacity of Gan river basin; Form the point of policy optimization, the research carried on a quantitative analysis of the effect of the three policies to promote the upper limit of the water ecology carrying capacity, and designed a comprehensive scheme integrating the decreased economic development speed, energy efficiency and cleaner production, and strengthening the prevention and control of the pollution, which will be a possibility to realize the sustainable development of the water ecology carrying capacity of Gan river basin.To simulate the long terms dynamic process of the system of the water ecology carrying capacity of Gan river basin, the causal loop diagram of the system of the water ecology carrying capacity of Gan river basin is used to simulation the relationships between subsystems and search for operating mechanism of the system. By studying water pollutant total amount, the restricting factor of improving the water ecology carrying capacity, we have come to the conclusion that pollution treatment is the most effective measure to improve the water ecology carrying capacity, and established the minimal standard of the ecological water requirement to shun the unpromising way of "first pollution, last treatment"; Then, based on the system dynamics modelⅠof water ecology carrying capacity of Gan river basin, researching for the cause and effect relationships between the variables and the endogenous course of the variables, we built a new model, that is the system dynamics modelⅡof water ecology carrying capacity of Gan river basin. To contrast the simulation results of modelⅠand modelⅡ, it showed that the endogenous of the important variables can simulate the real performance very well, embody the systemic self-organization and internal coupling.This paper supplied a modeling procedure by the qualitative and quantitative analysis and static and dynamic simulation, that is, the linear dominant structure model- static model- the cause-loop diagram- verifying the cause-effect relationship-dynamic model, which offers a referential value for modeling approach.