Research On Delimitation Of Urban Growth Boundary (UGB) In Zhengzhou Central Urban Area Based On The National Territorial Spatial Planning System

In the context of the new era of territorial spatial planning,the urban development approach has begun to change from growth-driven to connotation-managed,with the aim of promoting high-quality development of urban space through the mechanism of reduction and pushback.Urban Growth Boundary(UGB),as a management tool to control urban sprawl in the overall urban design,plays a great role in practicing the concepts of ecological civilization,agricultural protection and urban-rural integration.At the same time,the report of the 19th National Congress of the Communist Party of China has clearly pointed out that the“three control lines”are the insurmountable red lines for promoting urbanization and constantly improving the relationship between the three spatial patterns,which is the institutional guarantee and policy implementation.Therefore,the scientific and reasonable delineation of urban growth boundary is a key means to promote the transformation of spatial structure,protect agricultural production,and balance the contradiction between ecological environment and urban expansion.In this context,the thesis firstly reviews the research process of urban growth boundary at home and abroad,defines its concept and connotation,and proposes“three zones and three lines(urban space,ecological space and agricultural space,corresponding to the three control lines of urban development boundary,ecological protection red line and permanent basic agricultural land,respectively)”as the spatial identification framework on the basis of summarizing practical cases and technical methods.The spatial identification framework is used to delineate the comprehensive urban growth boundary by using the“prohibited”,“reverse”and“positive”thinking.Using the central city of Zhengzhou as a case study,we analyze the basic urban profile,spatial evolution and influencing factors as the basic conditions for boundary delineation.Using the LESA comprehensive system to determine the spatial distribution of high-quality basic farmland and the ecological protection red line area by the comprehensive suitability evaluation of ecological status,both of which together define the“prohibited”development area of the city.The spatial scope of the Minimum Cumulative Resistance(MCR)surface and the suitability zoning were constructed by combining the MCR model and other methods to form the background constraint of the“reverse”resistance to urban growth.Based on the results of the above steps,we delineate the“positive”driving mechanism of the city by selecting the potential factors for urban expansion and simulating the future spatial pattern changes.Finally,with the results of the above steps,the rigid UGB and the flexible UGB,which focus on the dynamics of urban development,are delineated respectively,and the practical application of the boundaries and the policy advice on the function and utility of the boundaries are discussed,with a view to providing scientific suggestions for the development of Zhengzhou’s territorial spatial planning.The main conclusions include:(1)The spatial form of Zhengzhou’s central urban area changed significantly from 2000 to 2020,with the areas of urban land,rural settlements and other construction land increasing by 193.36,1.07 and 16.13km~2,respectively,which also produced many realistic problems such as land structure disorder,environmental quality degradation and urban change obstruction.(2)The area of basic farmland area,farmland reserve area and non-farmland area identified by LESA comprehensive evaluation system is 41.99,162.18 and 48.96km~2 respectively,and the area of ecological protection zone and ecological control zone identified by comprehensive suitability evaluation of ecological position is 57.68 and28.19km~2.The above areas are important for the construction of urban security pattern,and the basic farmland area and ecological protection zone belong to the prohibited development zone in urban construction activities.(3)From the MCR suitability zoning,we get five types of spatial scope:key construction zone,optimized construction zone,construction buffer zone,critical restoration zone and prohibited construction zone,whose areas are 481.28,195.15,174.89,122.89 and 48.96km~2 respectively.The above areas are the classification of the background constraints of the study area,which can accurately guide the development and construction activities to extend and approach the suitable areas.(4)Comparing the spatial simulation results of the five scenarios of natural evolution,arable land protection,ecological priority,excessive construction and sustainable development,it is found that the sustainable development scenario can control the ratio of the construction land area to 66.16%and ensure the basic construction area.This scenario can be judged as the dominant paradigm for future urban development;(5)The area scale of rigid and flexible UGB is 712.2 and 595.55km~2 respectively,which plays an obvious role of bottom-line constraint and planning guidance for urban development,regulating the spatial pattern and guiding the boundary of land development.The effectiveness of regulating spatial pattern and guiding the boundary of land development also needs the supporting system guaranteeing the rights and interests of government,market,public and law.