Studies On Regulation Of Urban Land Expansion Based On Smart Growth Theory

Smart growth theory, a new urban development idea, has gradually matured and made great progress in developed countries. It emphasizes the overall harmonious development between social economic and natural environment through function replacement of urban land, control of urban boundary delimitation, the ecological protection, urban renewal and other means to make the city compact, focused and develop efficiently. At present, most cities in our country expand in a "pie" mode with the kernel as the center, resulting in loss of control of city size and the inefficient use of land resources and continually aggravate the contradiction between urban development and land demands. Therefore to a great degree it restricts its sustained and rapid development.In new version of Quanzhou City General Plan (2008-2030) the scope of central districts further expand into980km2. Based on the previous version, the towns included in central districts of Quanzhou also face to choose the path and mode of urban development. Smart growth theory will no doubt provide beneficial references for its urbanization. It has a practical significance in settling a series of problems in rapid urbanization under land constraints. This paper set the central districts in Quanzhou as an example to carry out a study between land constraints and smart growth, mainly including four parts:At first the paper mainly introduces the research background, domestic and international progress in the study; describes the natural, socio-economic profiles and features in the central district of Quanzhou. It is of great significance to strengthen the downtown building to alleviate land usage issues in city and promote high efficient and intensive land use. Secondly the paper analysises the current land use status in central district of Quanzhou and evaluates the land use efficiency. Based on it, it summes up characteristics and problems of the downtown land use. After that, through the establishment of SLEUTH cellular automaton model, it sets two scenarios of free expansion and preplanned growth to simulate and predicts the development status in the downtown in the future and confirms that the scenario of preplanned growth is more appropriate for urban growth; then analyzes spatial variation, overall pattern and influencing factors of urban expansion in the optimal scenario in Quanzhou City. Afterwords it bases on two approaches, simulation of urban expansion and population prediction to comprehensively estimate the recent demand of construction land in central district. And figure the potential of construction land supply in aspect of stock and increment, According to the analysis of balance between supply and demand, the paper come up with strategy of land use balance in three respects:rigid control, lead in advance, content development. At last, it proposes the guidelines for implementation of smart growth in Quanzhou, including regulation of demand and supply of construction land, direction of urban development and setting boundary delimitation, the guidance of transport infrastructure on land use, the optimization of industrial structure and layout. These measurements make up the regulation system of urban smart growth under land restrain. This paper is to carry out the empirical analysis to point out the priority of implementation of the smart growth in city.The conclusion is mainly divided into five parts:(1) Cohesion of central district in Quanzhou is not strong and land use efficiency is low, strengthening its construction is conducive to fostering growth kernel and promoting efficiency of land use. The overall economic strength is strong in Quanzhou and it has typical characteristics of the county economic development. However the cohesion of social-economic in central districts is not so strong and can not fully play a "leading" role, showing "a little horse drew a large cart". To develop around the gulf and Coastal region and strengthen the construction of central city can effectively solve the problem of development and ecological environment. It is conducive to a higher level of intensive land use and protection and fully plays the leading role of downtown cohesion. As a result it will bring out the whole prosperity of Quanzhou.(2) The growth potential in the central city is fairly strong. The results of simulation based on SLEUTH model of urban expansion better reflect its direction of urban development in the future. According to the results of simulation based on SLEUTH model of urban expansion, the newly increased land in Quanzhou in2020reach by104.73kmz, with an increased proportion of78.45%; in2030new urban land is added to158.24km2, with an increased proportion of118.53percent. It shows a strong potential for future urban growth. The results of the simulation better reflected the general direction of urban development, newly increased land are mainly distributed around the central bay of Quanzhou and Huian county, which lie on the east of central district. The external urban expansion is rather slow. The result mainly corresponds with the overall planning in Quanzhou which includes "toward the east, down to the south, give priority to the north, control the west".(3)There are diversities in urban land expansion in long-term and short-term. In the overall pattern of urban development, the industrial land plays a leading role with residential land as an assistant and other land expansion co-existed." In2008-2020, the average annual growth rate of urban land expansion is0.9%. The expansion rate of urban units grows like a "circle" while the center area of active expansion has a feature of "distribution". As the year goes on, the growth rate of land expansion in central districts decreased gradually. In2021-2030, its average annual growth rate of urban land decreased to0.55%, the growth rate of urban units shows characteristics of "Position type" structure, while the active expansion area show a feature of "centralization".(4)According to the calculation of increasing potential of land demands and supply in the central city, this paper proposed land use balance strategy and conceive a regulation system of smart growth for urban land under the land constraints. At present, the overall land demand for construction in central district is51.77km2. Including44.04km2of land demands in towns, there are7.73km2of land demands including residential settlements, water facilities and other non-urban construction usage. The overall supply potential for construction is as large as48.08km2with stock9.40km2and increment38.68km2.At present, the increment has a large part in the construction land supply while the stock is just supplemented in central districts with a margin of3.68km2. According to analysis of the land balance, this paper proposes some strategies to balance land use through the following three aspects:control rigidly, guide in advance, develop connotation and preliminary design the regulation system of smart growth under land restricted. There are some innovations in this research as follows:(1) This paper improves the SLEUTH model and innovates in terms of its application. It makes full use of it and establishes and applys the model in this paper to predict the urban development in the future. The model is improved according to the obejective of research. So it sets two scenarios of free expansion and preplanned growth to simulate and predict growth of urban land in Quanzhou City, then analyzes spatial variation, overall pattern and influencing factors of urban expansion in the optimal scenario in Quanzhou City.(2) It conceives the regulation system of urban smart growth under land constraints including following aspects:mode of supply and demand of the construction land, the direction of urban development and new boundary setting, the guidance of transport infrastructure on land use, the optimization of industrial structure and layout of the city finally the paper points out the focus of implementation. And it is applied to an empirical study.