The Negative Approach to Urban Development in China

The Negative Approach to Urban Development in China : Design Ahead of Time: Urban Growth based on Ecological Infrastructure Kongjian Yu The Graduate School of Landscape Architecture, Peking University Turenscape, Beijing, China Lecture Abstract The Concept: 　　TIME, in the conventional model of urbanization, is visualized in the concentric annual-ring like sprawl. For a long time, greenbelts and green wedges were seen as landscape structures to stop and prevent this ever lasting sprawl, and they were pre-designed in the comprehensive master plan. Current evidence, at least based on US (the Washington DC region), and also the Chinese examples, show that these greenbelt and wedge dreams have failed. Some of the major reasons for the failure of the greenbelt and green wedge to prevent urban sprawl include: 　　(1) They are usually planned artificially and arbitrary and are lack of the intrinsic relationship between the green elements and the living earth system 　　(2) Lack of usage by the residents, due to their accessibility and lack of connectivity between green space and housing projects, etc. 　　(3) They usually function only as barriers to stop the urban sprawl processes, and are lack of integration of various functions, such as flood control, creational use, heritage protection, and habitat protections. 　　(4) They quickly become development opportunities when peripheral pressure increases. 　　(5) They are impossible to administer and safeguard in a metropolitan region that is fragmented into a myriad of local governments, cutting across greenbelt and wedge jurisdictions. 　　By contrast, the search is on for a more differentiated, fine-garin ecological integration model that can be envisioned, implemented and managed at all scales. As a consequence the ecological planning approach has risen to prominence again typically under the flag of McHarg’s Layer model, try to provide land use plan some sound ecological basis, in which: 　　TIME is visualized as a string that links, and as a tool that enables understanding of, and integrates, vertically different layers of physical natural and cultural processes, namely from the earliest geological processes, to soil processes, vegetation processes, and finally, ‘on top’. the most recent layer of the cultural processes. 　　It is a vision of progress - of natural evolution based on the intrinsic values of a specific site on the earth. The core for this model of ecological planning is that urban development or land use can best be planned by fitting. Through the maximum fitting of the land use pattern to the intrinsic values on the earth, the best development pattern can be achieved. 　　These two models, namely the conventional urban growth model and the ecological planning model, are incompatible. One of the obvious reasons is that the conventional urban growth is more than often a horizontal process, while the ecological suitability analysis is basically a vertical process. The green space based on the layering model can not only well protect the horizontal ecological processes, such as species movement in the system, it may actually become attractor for intensive urban development due to the higher economic value surrounding this green, which may eventually been encroached by development. 　　The research of landscape ecology, which focuses on landscape pattern, horizontal processes and change, provide us fundamentals in developing green infrastructure that can be used to integrate the horizontal processes of urban development with ecological protection, in this new ecological planning model: 　　TIME can be visualized as an multi-scaled ecological infrastructure, that safeguard the various ecological processes across the landscape and provide various ecological services for the sustainability of a region and a city such as water and flood processes, biodiversity protection and species flow, heritage corridors and recreation: At the large scale, the ecological infrastructure is represented as permanent regional landscape patterns of flood prevention, ecological networks, heritage corridors and recreational corridors, which are to be planned for protection forever and are used to define the urban growth pattern and city form; 　　At the intermediate scale, the regional ecological infrastructure is to be integrated into the interior urban structure, and become the urban green space system that integrate various function of commute, cycling, heritage protection and recreational activities. Ecological infrastructure at this scale changes slowly along with the growth and renewal of the city, it may take tens or hundreds of years. 　　At the small scale, the ecological infrastructure at both the large and small scale are to be used as the defining structure for urban land development pattern, and to be used to guide the site specific design. which can be changed constantly following the change of land use and seasonal or yearly change of processes, such as flooding, the functional shift of the places. 　　As an illustration to the above theoretical description, a cased study was presented in this lecture: 　　The Case study: Taizhou City, Zhejiang Province, China 1. The Background and Main Issue 　　The Chinese urbanization rate is about 1% annually. Almost 40% of the nation’s 1.3 billion now inhabit urban areas, and this number is projected to increase to more than 70% in the coming 15-20 years with cities sprawling at an unprecedented speed. At the east coast, where this project is located, the cities grow even much faster. In this process, land is overtaken indiscriminatively for infrastructure construction and urban development. As a result, the wetlands and water system on the land were destroyed and polluted, native habitats and biodiversity are getting lost, the hazards of flood, drought hazards and diseases are increasing, and the cultural identity of the landscape is getting lost. 　　As a traditional approach, greenbelts were planned to stop the urban sprawl, but more than often they are realized only on the paper. One of the main reasons for the failure of greenbelt concepts is that they are usually planned more artificially and arbitrary than the urban development itself, with functions only as barriers to stop the urban sprawl processes. New and effective tools have to be developed to address a wise and sustainable development of the limited land. 　　Taizhou is located at the south east coast of China, with a total area of 9411 square kilometers, and a population of 5.5 million. Of these only 0.7 million are live in urban areas; the urban population will increase to 0.9 million in 2010, and 1.3 million in 2020, and 1.5 million in 2030. Alhough quite rural and agricultural in character, it is now one of the fastest growing areas in China due to the booming of small private industries. Under the influence of the monsoon climate and being adjacent to the east sea, flood has been a major hazard. As an adaptation to the storm water and flood problem, the landscape has been shaped into a unique form featured with a network of water courses that integrate natural water systems, wetlands and man made ditches, as well as cultural heritages such as bridges, dikes, dams, and vernacular landscapes. This area has long been famous for the rice, fishery and citrus. It is also critical to keep in mind that arable and developable flat area is very limited in this area. 　　This water network landscape, which has been effective in safeguarding the agricultural processes in the past thousands of years, is now facing the challenge of being destroyed by the speedy urbanization process beginning in the earlier 1990s. The wetlands have been filled, rivers have been straightened and channeled, cultural heritages that are not listed as protected historical relics have been destroyed, visual and recreational experiences have been totally ignored. 　　In addressing the above situations, a project was then outlined to guide the urban sprawl and safeguard the sustainability of the living land and using a minimum amount of land for the natural and ecological considerations. 2. The Project’s goals and objectives 　　In this project, the planners take land as a living system, and develop an ecological infrastructure (EI), to guide and frame the urban sprawl. The EI is defined as the structural landscape network that is composed of the critical landscape elements and spatial patterns that are of strategic significance in safeguarding the integrity and identity of the natural and cultural landscapes and securing sustainable ecosystem services, protecting cultural heritages and recreational experience. 　　Like the urban infrastructure providing social and economic services (such as transportation, gas, sewage, etc.) that support the potential urban growth, the EI safeguards ecological services, protecting cultural heritages, providing visual and recreational experiences. 3. Targeted processes need to be safeguarded before urban growth 　　Three categories of processes are targeted to be safeguarded by the ecological infrastructure: 　　(1)The abiotic processes: the main focus is flood control and storm water management. 　　(2) Biotic processes: native species and biodiversity conservation. 　　(3) Cultural processes: Including heritage protection and recreational need. 　　A geographical information system (GIS) was established to store, overlay and analyze layers of natural, cultural and social economic data. 4. Defining an permanent ecological infrastructure at the large scale 　　The regional EI was planned through the identification of critical landscape patterns (security patterns) for the targeted processes. The security patterns are composed of elements and spatial positions that are strategically important in safeguarding the different processes of the landscape. Models including suitability analysis, minimum cost distance and surface models were used in the identification of security patterns for the individual processes. 　　Three security levels - low, medium and high - are used to define the quality of the security patterns in safeguarding each of the targeted processes. 　　Using overlaying technique to integrate the security patterns for individual processes, alternatives of regional ecological infrastructure are developed at various quality levels: high, medium and low. 5. Scenarios of urban growth pattern based on the regional ecological infrastructure 　　Using the three EI alternatives as framing structure, scenarios of regional urban growth patterns were simulated using GIS: the Adjusted Sprawl Scenario, the Aggregated Scenario, and the Scattered Scenario. 　　Comparative impact evaluations were made for these scenarios by a planning committee composed of decision makers of the city, planning experts from all over the country, stake holders of holders who are represented by officials from various functional departments of the Taizhou city government (including the departments of agriculture, water management, forestry, industry, tourism, finance, transportation, public affairs, security, culture education, tax, etc.), and representatives of individual villages who originally owned the land, representatives of real estate developers and representative of investors who are eagerly waiting to get the right to develop the land. 　　One of the three urban pattern scenarios was finally selected as the most feasible by the decision makers, after a long time and multiple brainstorms among the planning committee. As expected the Aggregated Scenario, which is based on the medium quality EI, was considered the more balanced and less difficult to be realized. 6. Innovative legislation to protect the EI 　　Green lines were drawn to define and safeguard the EI protection. These basic green lines are now being presented to the people’s congress of Taizhou City for legislation. After being passed by the congress, these green lines will become the first of their kind in China to protect the regional ecological infrastructure by the municipal law. 7. Defining ecological infrastructure at the medium scale 　　Based on the aggregated Scenario and the green lines of the regional EI, overall design and management guidelines were developed for the medium quality EI, and especially for the green corridors that function as critical EI elements in water management and biodiversity conservation, heritage protection and recreation. During this process of making design guidelines, time consuming interactions were made between the planners and local people, especially the local villagers whose land is either going to be developed or protected. 8. New models of urban land development: testing ecological infrastructure at the small scale 　　At a selected site (10 square kilometers in size), following the EI guidelines developed above, alternative urban development models were designed to test the possibility of building an EI based city. In these ecosystem services safeguarded by EI are delivered into the urban fabric so that the usual urban sprawl can be avoided. 　　These new urban land development models were presented to the developers and investors, as well as the city decision makers, to let them know that the business-as-usual models of land development can be avoided. The new way of development by building the EI into their land use scheme will not only help the whole city, but will also benefit the on site development ecologically and economically. These schemes show how the regional and large scaled EI can be realized also at the local and small scale land development to handle the problem of urban sprawl.