系统动力学模型在城市发展规划环评中的应用

鉴于作为评价对象的城市社会经济环境复合系统具有多目标、多要素、动态关联等突出的系统动力学特征,选择和应用系统动力学方法开展城市发展规划环评在理论上具有可行性和技术优势.作为典型资源型城市的山西省临汾市正面临转变发展方式和加快环境治理的紧迫要求,本文依托该市转型发展规划环评工作,在全面识别和剖析城市发展要素、现状问题及其成因基础上,以经济发展、产业结构、节能减排和环境改善为重点研究了规划要素间的动态反馈关系,以此构建城市转型发展规划环评SD模型,并对4个规划替代方案进行模拟和评价.结果显示,在环境目标刚性约束下所有替代方案均不能实现人均GDP翻番的较高经济增长目标,其中以较强环境约束为特征的“方案III”具有最好的环境与经济综合效果.据此评价建议临汾市应在确保实现环境改善目标的前提下主动放缓工业增长速度,同时加快以“煤焦铁电”为代表的主导产业结构调整并继续加大节能减排力度,全面提高城市可持续发展能力.

An application of system dynamics model into strategic environmental assessment of urban planning: a case study of Linfen city

Regarding the obvious features of multi-objectives, multi-elements and dynamic interlinks presented by urban complex system of society, economy and environment, the system dynamics (SD) method might be of great potential when applied into planning environmental impact assessment (PEIA) of urban plans due to the good theoretic feasibility and technical advantages. As a typical resource-based city in Shanxi province, Linfen was soliciting an imperative development transition and environmental treatment. Here, based on a comprehensive analysis of key development elements, current problems and driving factors of the city, the dynamic feedback relationships were first screened out among economic development, industrial restructure, energy saving and emission reduction, and environmental improvement. And then, a SD model was built up to simulate and assess the four proposed planning alternatives of urban transformation and development of Linfen. The results showed that if the maximum environmental restrains were employed, all the four alternatives would not be able to fulfill the planned growth targets featured by doubled per capita GDP. If the harder environmental restrains were adopted, the alternative III among the four would produce the best integrative effects on environment and economy of the city. Accordingly, the PEIA recommended the city to ensure the planned environmental improvements by slowing down the economic growth, restructuring the main industries represented by coal, coke and iron productions and power generations, strengthening energy saving and emission reduction, and lifting urban capacity of sustainable development.