The Delimitation Method Research Of Urban Growth Boundary

Since new century, the rapid process of urbanization which improves economic efficiency also brought the explosive population growth and space sprawl in big city, thus causing other issues such as traffic congestion, environmental pollution, haze sadistic, farmland dropped, etc. Although the government has always stressed on the metropolitan scale control, the fact was just another thing. Major cities in the planning position will become a mega-city, large city and even a huge city, so the land development scale are usually double the size together with its economies of scale. Therefore, the new urban planning approach implemented in 2006 clearly stated that the master planning outline and the central city zone planning must "Research the Urban Growth Boundary (UGB) of the central city zone, and determine the scale and scope of the construction land" However, from cities practices in recent years, the UGB showed greater randomness and differences in delineated principles and specific delineation methods, which enabling the lack of practical utility. Therefore, this article try to analyse the "Urban Growth Boundary (UGB) delineation methods and empirical research", and a cse study on the central city zone of Xi’an, so as to provide effective reference to the UGB scientific delimitation in planning.Based on the research of UGB theorys and special domestic institutional environment, the article first delimited the bottom boundary of ecological security of the Xi’an central city zone, for example; Secondly, a rational evaluation was made according the nearly 10 years’ macro strategic plans from region, urban and the central city zone 3 levels. Then the main nodes and extended spindles of expansion planning period were analysed and extracted based on the spatial expansion structure, and a long-term reasonable spatial expansion structure framework would be built out.After above, the article coordinated and dealt with the delineation between basic farmland protection and urban construction demand. Finally, it delineated the comprehensively UGB of the case area.In addition, the article exploratory proposed some about the delimitation subject and the establishment of adjustment mechanism, as well as three targeted guiding measures to internal and external. The main results were as follows:(1) Urban spatial structure is the skeleton that formated after long time development, and the scope of UGB have both effects of limitations and guiding to the urban spatial structure. Then before the UGB demarcation, we should firstly analy and make rational anticipation of the urban spatial extract trend in the planning period, and this time the UGB could form a lasting positive interaction with urban spatial structure,and guide the city to build a reasonable&solidified urban spatial structure. The urban form of both stability and characteristics will be made ultimately.(2) Through the rational analysis of space expansion trend of the central city zone in Xi’an, the main extension were defined in the planning period:the southwest spindle made by Feng River delta, Samsung Town, Chang’an industrial park; the north spindle across the Weihe River and made by Jingwei Metro, Gaoling town for two core nodes; the east spindle made by the International Port District as the core, directly and strongly to Lintong new district and its main city; the west spindle made by Feng East, Feng West Metro for support, and jointed to Xianyang city. Overall, both the western union and the east extension are more rapid, and will further widen the skeleton. Based on the comprehensive coordination of contradictions, the UGB of central city zone were delimited finaly.(3) After the UGB demarcation,we can mining the inefficient land for secondary updating in order to achieve inventory optimization; ans also get creative use from Architectural design to achieve incremental innovation. Another limitation of the urban infrastructure resources supply are effective to control the spread. At the same time, the external land use must be strict controlled, and initiatively guide the local nearest urbanization, as well as promote the integration of internal and external traffic actively.