Methods and case study on water ecological carrying capacity using SD model

Based on SD (system dynamics) model, a simulation and optimization method for water ecological carrying capacity was proposed, and the method was tested by its application in Changzhou city. The SD model was developed by Vensim DSS software. Using scenarios analysis, five scenario schemes including zero scheme, water saving scheme, low pollution control scheme, moderate pollution control scheme and high pollution control scheme were designed from the views of water saving and pollution control. The water ecological carrying capacity in Changzhou city was simulated by the five schemes, and the optimized scenario was screened by the genetic projection pursuit method. Results showed that the high pollution control scheme was the recommended one. By the recommended scheme, Changzhou city could burden a population of 4.81 million and GDP of 609.4 billion RMB. The utilization rate of water environmental capacity is up to 100%, and the water resources utilization rate cannot exceed 48.8%. It is pointed out that to achieve these goals necessary measures must be taken, such as improving the water use efficiency, reducing the growth rate of seriously polluting industries, increasing the investment of sewage treatment and enhancing the sewage treatment ratios, and so on. This study could provide not only a method for the assessment of water ecological carrying capacity, but also a theoretical basis for coordinated development of environmental protection and economics.EI0ARTICLE51352-13603