Kunming Ecological Infrastructure and Greenways, Kunming, China

Kunming Ecological Infrastructure and Greenways

Kunming, China 2010 Turenscape www.turenscape.com

The city of Kunming has a population of approximately 6 million people and is the capital of Yunnan Province in South West China. Kunming’s strategic location as the hub of transport links to South East Asia enabled the city to become the cultural, political and economic seat of provincial government serving 45 million people. The city stands at an elevation of 1900 metres above sea level in the heart of the Yunnan-Guizhou plateau and at latitude just north of the tropic of Cancer. Consequently the sub-tropical highland climate has earned Kunming the title of the ‘City of Eternal Spring’. Not surprisingly, Kunming is an important Chinese horticultural centre from which magnolias; azaleas, lilies and orchids are exported worldwide. The fertile plateau also produces important grain, vegetable and fruit crops. The ‘pearl of the plateau’ is Dianchi Lake, the sixth largest freshwater lake in China which lies to the south of the city and is connected to the Song Hua Ba reservoir in the north by the 23 kilometre stretch of the Pan Long River that passes through the city of Kunming. This idyllic landscape is surrounded by limestone hills rising above the plateau and has evidence of settlements dating from 279 BC. The modern city of Kunming began to grow and prosper with the arrival of the railway link from Hanoi in 1910. Since that time successive phases of development have taken their toll on the source of all life, the water systems that sustain the region. The most recent rapid growth of urban development (Fig. 2) has substantially decreased the permeable areas of the city increasing the general risk from flooding, particularly in the rainy season from May to October. Tragically, pollution levels of the Pan Long River system and Dianchi Lake have become dangerously high as the expansion of the city sewer system has not kept pace with the rapid growth of the urban areas. Additionally, heavy industrialisation along the riverfront has added to the high incidence of pollution. To confront this threat to the region’s health and vitality, Turenscape architects under the direction of Professor Kongjian Yu, undertook an unprecedented research project in 2008-9 to develop an all-encompassing project to rejuvenate the Pan Long River (Fig. 1).

Population | 566,974

Co-ordinates | 25°04’N 102°41”E

Elevation | 1,892 m (6,207’)

Precipitation | 1011 mm (39.8”)

Temperature | Average High: 21 C (69 F) Average Low: 10 C (50 F)

Humidity | 69.6%%

The master plan devised by Turenscape has four major objectives stated by the architect as follows and illustrated in Fig. 4 opposite. 1) The entire Pan Long River basin is to be re configured as a means to mitigate the threat from flooding. The hydrology scheme will also deal with the attenuation and purification of the city’s storm water. The scheme will incorporate the provision of public access to the riverfront. This element of the scheme will require the removal of the hard concrete embankment, semiculverted system, in favour of a regraded soft terraced and slope system of vegetated banks and pedestrian friendly access to the riverside. 2) The environmental upgrade of the Pan Long River is intended to rejuvenate the economy of the inner city by specifically increase the land values of the properties immediately adjacent to the remediated river frontage. 3) Particular attention is to be paid to the upper and lower reaches of the river, where the farmland and rural land-use is dominant. It is evident that the territory is one in transformation, but the project seeks to build upon the inherent qualities of the particular landscape features adjacent to the northern reservoir and the southern lake. 4) To initiate ecological restoration along the Pan River and the region as a larger system to increase biodiversity (including to collect water in the wet season and to release it in the dry season), to strengthen the link between the natural and cultural heritage and to create new systems for recreational and public space uses for Kunming and the Yunnan Province. To achieve these objectives and restore the ecological infrastructure of Kunming will require both ‘‘defensive measures’’ and ‘‘opportunistic interventions’’ in the key areas of landscape process described as:

Abiotic: Water management (Figs. 5, 6)

Biotic: Conservation of native species and the promotion of biodiversity (Figs. 7, 8)

Cultural: Protection of heritage sites and recreational pursuits, (both traditional and contemporary). Figs. 9, 10

These elements are illustrated cartographically on the succeeding pages.

Abiotics: Water management and the design of a new flood security pattern: The new flood security pattern was devised following extensive analysis of the existing river basin (Fig. 5 above) from the Song HuaBa reservoir to Danchi Lake. By appraising the systems on a regional scale the hydrologists looked to provide alternative solutions to the piecemeal, heavily engineered systems of concrete dams and semiculverted channels that currently blight the landscape. Alternatively, landscape security patterns were set up to provide natural water retaining capacity by capitalising on the potential assets of the natural landscape for water retention.

This is done primarily through an interconnecting network of wetlands, flood meadows, waterways and lakes. The cartographic approach enables the low, medium and high security patterns to be established for the potential 20, 50 and 100-year flood instances as detailed in (Fig. 6 above). The rivers canals, ponds and wetlands are enlarged; additionally new water bodies including flood meadows are created to form a self-sustaining water system. New river and canal embankments are designed to soften the landscape.

Biotic: The strategies for conservation of native species and the promotion of biodiversity were developed through analytical mapping of the river basin (Fig. 7). Particular attention was paid to land use and vegetation in relation to wildlife habitat and the principles of landscape ecology. The maps revealed critical areas that required careful managing to ensure the preservation of habitat and the related movement corridors.

Design interventions included the construction of underpasses and bridges for safe travel of wildlife where a natural corridor might intersect with road traffic (Fig. 8). Similarly, it would be necessary to ensure that water flows in all seasons remain uninterrupted for the preservation of aquatic life forms.

Cultural: The protection of heritage sites and the promotion of recreational pursuits (both traditional and contemporary) was approached in the same analytical way as water management and protection of wildlife. Sites of historical interest previously neglected or hidden in the urban expansion were mapped alongside the parks and recreational areas (Fig. 9). The exercise revealed many hidden gems in an area of outstanding resources, both man-made and natural.

One of the key concerns in planning the preservation of these resources is the issue of connectivity. The planning carefully considers the future use of a network of roads, pedestrian and cycle paths and the Pan Long River and tributaries (Fig. 10).

The southern downstream area running into Dianchi Lake is planned as a delicate balance of agricultural land, existing villages and new urban development designed to compliment the existing settlements. The vitality of the scheme relies upon the quality of treated sewage water (grey water) being improved prior to discharge (Figs. 11, 12). The Pan Long river remediation project commenced on site in December 2009 with phase 1 of the project targeting the 8.3 kilometre section of riverbank between the Guannan Bridge and the mouth of Dianchi Lake.

To strengthen the soil banks against water flow erosion a policy of live staking (Fig. 13) was employed in conjunction with riprap. Porous paved bicycle and pedestrian trails have been introduced along the course of the river. Wooden platforms and outdoor furniture create spaces for quiet contemplation or social gatherings reconnecting the population with the riverfront. The upstream area (Figs. 18, 19, 20) near the Song Hua Ba Reservoir cluster of new housing development, wetlands and swales will coexist with the conservation of existing villages and fishponds.

Fig. 14 above | Fig. 15 below

Fig. 16 above | Fig. 17 below

In the densely urbanised central stretch of the river the remediation plan includes the development of new parks and gardens connected to existing public open space and cultural amenities. Regrading and soft landscaping the existing channelised banks will enable the creation of public promenades and crossings, promoting significant changes in the quality of life of the citizens of Kunming. The movement for these changes has manifested itself in excursions and walks along the river being led by environmentalists and people of all age groups who enthusiastically lobby for full implementation the scheme.

Fig. 22 (above) details designs to re configure riverbank conditions. The designs provide a series of different relationships between land and water creating a diversity of experiences between landscape, urbanism and infrastructure by combining soft landscaping, a variety of vegetation types, surfacing and outdoor furniture.