Study On The Urban Spatial Expansion From Smart Growth Angle

Nowadays,with the development of urbanization and economic of China, All cities in our country are going through a historical process of spatial expanding and great changing of structure form, so that all the cities want to be a"globe city"or"super city". However, a series of crises are coming, such as decreasing of cultivable plough, overloading of the environment, low efficient of development and lagging behind of basic facilities. So it is important to choose a reliable way to control the spatial expansion,which not only enhance the goal of using the land efficiently, but also improve the development of urban economic and environment. Therefore, it has aroused a wide spread attention for different levels of governments and institutes.Urban spatial expansion is one of the most important features of the urbanization, its outside appearance is the scale expansion in macroscopic view and different kinds of aggriculture land change into the urban land in microscopic view. The essence of urban spatial expansion is the course of non-constructive land transforming into the urban land by the different impetuses from inside and outside, at same time it also includes the change of spatial elements, the spatial form and structure from the plane and vertical. Urban spatial expansion always faces much problems such as growth direction, non-economic, ecological environment problem, and policy problem that how to choose the best model and way for spatial expansion.In western countries, confronting with the rural sprawl, a comprehensive new theory named"smart growth"is springing up, whose basic idea is the compact landuse, resource savinge and much tools use ness together. Therefore,"Smart growth"can be viewed as a way of analyzing the reasonable of urban spatial expansion.Based on the analysis of theory and practice of the urban spatial expansion and"Smart growth", the paper analyze the mechanism function and aim function that the smart growth improve the urban spatial expansion, and reveal the identity in essence each other,and then the paper put forward the theory framework based on the smart growth theory. Subsequently, the paper take the LanZhou city as a case, analyzed the construction land in lanzhou city and urban area from the smart growth angle, then put forward the measures of smart growth. The main research results as follows:(1) It is a necessary choice for urban spatial expansion based on the Smart growthUnder the conditions such as lacking of farmland, exceeding creep of urban ,rapid development of city economic, It is the requirement of the fact and the developing of times that we should choose the way of impact expansion. Although there is great difference of the urban expansion between China and American, we still have sameness in saving the land, improve the low efficient landuse, enhance the public traffic, reform the traditional neighbor community.(2) The essence of Smart growth is the comprehensive strategy that solves the problem of urban spatial expansion by regulation and control.Smart growth is a comprehensive tactics which contains different levels of city's development. At first, it is a synthetically scheme that comes from a lot of distant view schemes of regional area, urban area, and community area's by regional question's distinguish extensively, and a synthetically aim that contain all kinds of development of the open space, filling vacancy, redevelopment area, new growth area, community centre and corridor, and a synthetically compared process of different scheme by the principle of variety, walk equal, mixed land use and constriction of regional area and community area. Secondly, it is a synthesis of many kinds of tactics tool and laws and regulations, its tactic including the basic tactics of community's transformation, road transformation, brown field redevelopment, mixed land use, and regional tactics of traffic planning and open space protection, and rationally choose policy tools such as the law, economy, administration, etc. Thirdly, it is also a comprehensive decisions with extensive coordination among the government organization and non-government organization and the masses.(3) Smart growth is the guide of the urban spatial sustainable expansion.Smart growth have a positive and reasonable adjust function and optimize function on the factors of urban spatial expansion, not only promoting the reasonable transform- tion of the natural environment, contributing to upgrade industrial structure, ecology and more educated, but also help to develop agglomeration effect, traffic technique and the reasonable alternative to the control measures of programming. At same time, smart growth can facilitate rational development of the four great goals on urban spatial expansion, whose development can prosper urban economy, improve the life quality of urban and rural residents, protect the environment and save resources, and whose ideas reflected intensive compact thought, harmonious comprehensive thought, resource saved thought, diversified thought and bear the weight of limited though. Therefore, smart growth also acts as a gauge and rule for rationality of the urban spatial expansion.(4) The model of spatial expansion of Lanzhou need reformNeither the spatial expansion of construction land in Lanzhou city or Lanzhou urban area, it all has the distinctive sprawl along the valley and regional traffic. especially, the spatial expansion of Lanzhou urban area is more typical and going through the original axis leap-over expansion toward the banding form mode, but now, it is confronted with the fate that the reasonable group structure is being destroyed by the group's drawing close, mergering constantly and growing together, and with the result that sustainable development of Lanzhou urban area is being influenced seriously. Therefore, with the population growth and unreasonable expansion, it is an inevitable choice to set up the newly developed area by jumping out the river valley, and to protect the farmland in the valley and river ecological system by setting up the boundary of cities and towns, and to choose key county and town as the core of regional development based on the smart growth strategy. Especially, according to river valley environmental condition, the northern expansion strategy has important meaning of ecological security and regional development, which not only can increase the land supply by developing the wasteland or unutilized land, avoid route reliance along the river valley, and protect the fragile river valley ecosystem relatively, but also can prevent possible decline of old urban area far from the new development zone.(5) The river valley is the key practicing area of lanzhou smart growth.Neither the spatial expansion of construction land in Lanzhou city or Urban district, the results are all have obviouse influence on river valley. At first, the construction land of Lanzhou city mainly concentrated in the river valley. Research result show that the construction land in river valley area accounts for 50.8 % of total construction land in 1996, and be up to 56.6% in 2005, and show that construction land relying mainly on river valley has taken up much cultivated land and ecological water areas directly, has had influencing on the spatial structure of urban system greatly, and has brunt many problem with high pressure and cost, such as environmental pollution, calamity security, traffic, etc. Secondly, the expansion of construction land of Lanzhou urban area produced prominent influence on cultivated land, ecological water areas, open space, and spatial structure of urban area too. Therefore, It is the key region for construction land expansion of Lanzhou urban to implement smart growth tactics in river valley in the future.Compared with the research findings, the innovation and development of this study is mainly manifested in the following aspects:(1) Study of function mechanism and inherent identity of smart growth on urban spatial expansion.The thesis analyze the function mechanism of smart growth on the factors of urban spatial expansion, indicate that smart growth not only generate much positive impacts on urban spatial expansion, such as the rational transformation of natural environment, upgrading industry, ecological industry, industry knowledgeable, and enhancement of agglomeration effect, innovation of traffic technique, rational choice of planning control measures, but also facilitate the rational development on urban spatial expansion, such as the prosperity of urban economy, improvement of the life quality of urban and rural residents, environment protection including natural ecological environment and social humane environment, and resource thrift including cultivated land, water resource, etc. Therefore, non only urban spatial expansion based on the smart growth embody ideological connotation of intensive compact thought, harmonious comprehensive thought, resource saved thought, diversified thought and bear the weight of limited though, but also offer the research thinking from new perspective for urban spatial expansion, and enriches basic method and tools of urban spatial expansion. In all, smart growth and urban spatial expansion have inherent identity.(2) Practice analysis of regulation and control of foreign urban spatial expansion from smart growth angle.It is important to investigate practice of regulation and control about urban spatial expansion, and it is more about those cities that have already gone through fast urbanization stage. Not only can practice investigation facilitate understanding spatial characteristics of urban expansion during fast urbanization stage, but also can facilitate knowing the laws of thought and tactics change of adjusts and controls. So, no matter the analysis of smart growth practiced in U.S.A, or the analysis of expanding regulation and control based on smart growth practiced in Britain, France, Japan, etc. all these lay solid practice foundations for scientific understand expand tactics on the basis of smart growth, and offer the opportunity of using for urban expansion lessons under the back of GDP guide, deviating from our country fundamental realities, resource environmental foundation and urbanization needs, at same time, put forward prerequisite and key of drawing lessons from comparison analysis.(3) Analysis and evaluation of construction land expansion based on the smart growth of Lanzhou.Lanzhou lies in the western low-developed area where ecological environment is more fragile, so that she has a wide gap comparing with the eastern area under the great restrictions. Therefore, it is more urgent to choose the smart growth strategy for Lanzhou spatial expansion. The thesis quantitatively analyze the spatial expansion process, and its characteristics and mechanism through GIS, SPSS methods from the two levels of Lanzhou city and Lanzhou urban area, and reveal the basic laws of river valley city's construction land expansion. And on the basis of smart growth, the thesis quantitatively analyze the spatial expansion effect, form the basic trend, and then put forward the strategy-based measures and policies suggestion for river valley city's expansion.