基于SD模型的水生态承载力模拟优化与例证

提出了系统动力学和投影寻踪法的水生态承载力模拟和优选方法，以常州市为例进行实证研究. 采用情景分析法，从节水和污染控制方面，设计了零方案，节水方案，污染控制低方案，污染控制中方案和污染控制高方案等5个情景方案. 通过Vensim DSS软件建立SD （system dynamics）模型和模拟仿真平台，模拟了2020年常州市水生态承载力，得到5种情景方案的模拟结果. 采用遗传投影寻踪法，对5种情景方案进行优选，推荐方案为污染控制高方案，在该方案下，2020年常州市可承载的人口数量为481万人，GDP总量可达到6094亿元，相应的水资源开发利用率为48.8%，最大水环境容量利用率为100%，要达到以上水生态承载力目标，必须提高水资源利用效率，降低重点污染行业增长速度，增加污水治理投资金额，提高污水处理率等. 研究结果为评估水生态承载力提供了理论依据，为研究区水生态环境保护和经济社会发展提供了决策参考.

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.