American Society of Landscape Architects ASLA 2005 Professional Awards
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The issue: The urban sprawl of Taizhou city.
The objectives and methodology: build an ecological infrastructure (EI) to safeguard the natural, biological and cultural processes and secure the integrity and identity of the landscape, and provide sustaining ecosystem services to the city.
Large scale: security patterns of flood control.
Large scale: security patterns for biodiversity conservation.
Large scale: lanned landscape security pattern for biodiversity conservation.
Large scale: security pattern for cultural heritage protection.
Large scale: security pattern for recreation.
Large scale: overall regional ecological infrastructure.

The Growth Pattern of Taizhou City Based on Ecological Infrastructure, Taizhou City, Zhejiang Province, China
Peking University Graduate School of Landscape Architecture & Turenscape, China

"Analysis is very comprehensive. . . creates framework from which various architectural and landscape architecture forms can emerge. . . starts with ecological and environmental issues."

— 2005 Professional Awards Jury Comments

The urbanization in China increases about 1% annually. There is less than about 40% of the nation’s 1.3 billion population now inhabiting urban areas, and this number will increase to more than 70% in the coming 15-20 years with cities sprawling at an unprecedented speed. In the east coast area, where this project is located, the cities grow even much faster. In this process, land is taken over indiscriminately 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 paper. One of the main reasons for the failure of greenbelt concepts is that they are usually planned more artificially and arbitrarily 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 southeast coast of China, with a total area of 9411 square kilometers, and a population of 5.5 million. Among them only 0.7 million people are now living in the urban area, and the urban population will increase to 0.9 million in 2010, 1.3 million in 2020, and 1.5 million in 2030. Though quite rural and agricultural, it is now one of the fastest growing areas in China due to the booming of the small private industries. Under the influence of the monsoon climate and being adjacent to the east sea, flooding 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 developeable flat land is very limited in this area.

This water network landscape, which has been effective in safeguarding the agricultural processes for 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 channelized, cultural heritages that are not listed as protected historical relics have been destroyed, and visual and recreational experiences have been totally ignored.

In addressing the above situations, a project was outlined to guide the urban sprawl and safeguard the sustainability of the living land, using a minimum amount of land for the natural and ecological considerations.

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.

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.

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.

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 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 representatives 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.

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 procedure. 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..

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.

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 ecosystems, 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 onsite 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.


Urban growth scenario: the adjusted sprawl. At a lower security level, the EI will allow the city to accommodate a maximum population of 5 million, and yet still keep a minimum critical landscape structure in safeguarding the integrity and identity of the landscape, and provide minimum ecosystem services.
Urban growth scenario: the aggregated urban pattern based on the EI at a medium security level.
Urban growth scenario: the scattered urban pattern based on the EI at a higher security level.
Medium scale: EI corridor design guidelines
Small scale: the slice alternative. A site of ten square kilometers was selected to test the possibilities of new urban development patterns based on EI. Three alternatives are proposed: the SLICE, GRID and WATER TOWN. The slice alternative lets the ecological services from the regional EI be delivered through corridors and penetrate into the urban fabric just like vegetable layers in a sandwich.
Small scale: the grid alternative. A grid system of green instead of roads to deliver the ecological services into the urban fabric
Small scale: the water town alternative. Flood hazard is to be avoided through retaining and diverging water, but not by channelizing and damming. Let one river become ten streams and let the ecological services from the EI penetrate into the urban fabric and individual households.
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