城市增长边界分析方法研究——以长江三角洲常州市为例

诸多国家已采取城市增长边界(Urban growth boundary, UGB)对策以抑制城市蔓延,我国目前城市与土地利用规划也明确要求划定UGB,但其分析方法研究还较薄弱。综合系统动力学模型、元胞自动机及城市承载力分析研究常州市区UGB,结果表明:预测到2020年常州市区城市建设用地面积为30 847 hm²,北部和南部组团外延增长、主城区及南北组团内部填充同步发展,UGB由沿江-德胜河-沪宁高速-新孟河-德胜河-武宜运河-沿江高速-沪宁高速-市域界限等围合而成;模型预测的UGB与GH-UGB(实际规划UGB)北部和东部空间拟合良好,西部和南部拟合较差,表明模型预测对空间整体和要素联系考虑不足,而用地规模偏差则表明模型预测更为客观;UGB分析方法在政策、空间规划理念和整体格局上有待完善。

Analysis Method of Urban Growth Boundary of the Changzhou City in the Yangtze River Delta

Urban growth boundary(UGB) is a common tool employed by planners to constrain urban expansion in order to increase density of urban services and protect surrounding rural landscapes.Many countries have adopted the method of UGB to control urban sprawl.China’s current urban and land use planning start also to have a clear requirement to delineate UGB,but the analysis method is also relatively weak.Especially,few models have been developed that simulate the UGB.We use system dynamics model,cellular automata in combination with the analysis of urban capacity to study the UGB of Changzhou City.Firstly,based on the analysis of the system dynamics model,urban land area of Changzhou City is 30847 hm2 by 2020.Urban growth mainly performs the urban land spread model of urban fringe area,simultaneously,and infill development model in inner city area of the northern and southern groups and the main city area.The boudaries of urban growth is enclosed along the Yangtze River-Desheng River-Shanghai-Nanjing Expressway-New Meng River-Desheng River-Wu-Yi Canal-Ningli high-speed-Shanghai-Nanjing Expressway-city district boudary.UGB curve simulated in the paper and GH-UGB proposed in actual urban comprehensive planning spatially fit well in the northern and eastern parts,but not in the western and southern parts.We think that it reflects the flexible nature of planning tools and the deficiencies of model prediction on considering macro-space pattern and the elements inner contacts of urban system.However,the forecast value of urban land size has a weak gap between the UGB and GH-UGB,and it reflects the subjectivity of the planning tools and the objectivity of the model prediction.This method in our paper has the advantage of using a variety of model combined with the urban capacity analysis,but needs to be improved in fully considering random policies,urban elements contacts and spatial overall pattern.