Yuan and Anjing in Yunyan District Guiyang

The Yu'an and Anjing district, in the centre of Guiyang City, is sparsely inhabited. The people living in the area - mostly farmers - are poor and live in bad conditions: hardly any sanitation, some chemical factories and a polluted river nearby. Although the density of houses is relatively low, every part of the area is in use for agriculture or living. It is almost impossible to find a place where the natural undisturbed landscape can be experienced. The natural landscape can be characterised as a hilly area with sometimes very steep slopes, cut through by a scenic, but polluted river: Nan-ming river. The visual qualities can be defined by the constantly changing views on the river with some times high value historic elements and the different mountains. This scene after scene sequence offers potentially a very beautiful landscape. Because of all the differences in slopes, hilltops and relatively flat areas the biodiversity of the area is potentially high, though in practice very low. This is caused by a wide spread pattern of all kind of buildings, small factories and small-scale agriculture (Atkins, 2007). The intensive use of the landscape not only causes a low biodiversity, it also decreases the visual quality of the landscape (Bing et al. 2008a).

2.9.2.1 Climate Change Effects

Guiyang falls within the monsoon climate in subtropical zone that is temperate and humid without severe winters or hot summers, characterized by abundant rainfall and longer frost-free period, with the annual average temperature 15.3. The hottest days in July are only 24°C on average and the coldest days in January 4.6°C. The rainfall is 1197 mm of which around 75% falls between June and October. The relative humidity is 76.9% and the frost-free period lasts about 270 days. The hottest day occurs in late July, and the coldest in early January. But drought or waterlogging often occurs because of the rainfall unbalance among the seasons. It is expected that precipitation in summer periods will decrease and that floods increase due to more intense showers. The effect of intense showers in combination with the intensively used landscape is that large parts of the hills will be ecological worthless.

The aim for the project site is to increase the biodiversity in the hill area and to provide year round enough water available both for drinking water as well as for the landscape. The approach chosen therefore is to minimise the impact on the landscape and realise the building program at the same time.

2.9.2.3 Analysis

If the area is analysed on density options several scenarios can be developed (Fig. 2.30).

In case the buildings are not spread over the entire area, but are concentrated along one major road (1140 m alt. and 80 m. wide) the total program can be realised, keeping the rest of the area free from buildings. This contains several advantages. If the mountaintops are kept free from building activities, these areas offer space for water retention and the biodiversity can be increased. Also, the visual quality is improved, because the mountains stay visible as distinctive landscape elements in the area. This concept can be called: 'living on top of the world' (Fig. 2.31)

2.9.2.4 Rainwater Approach

The increase of biodiversity can be reached if the rainwater is stored as long as possible on the hills and the hillsides. Every level of the hill contributes to the cleaning and storage of rainwater (Fig. 2.32).

Fig. 2.30 Conceptual analysis of building capacity and the sensitive landscape by Prof. Dr. Teake de Jong (Source: Bing et al. 2008a)

Fig. 2.31 Living on top of the world: the concept of increased building densities and 'naturalising' the landscape (Source: Bing et al. 2008a)

Fig. 2.31 Living on top of the world: the concept of increased building densities and 'naturalising' the landscape (Source: Bing et al. 2008a)

Fig. 2.32 Landscape typologies and appropriate rainwater measures (Source: Bing et al. 2008a)

1. TopMountain. Mountains summits are kept free of any building. These places are reserved to retain water as much as possible and to improve the natural quality and biodiversity. The rainwater is kept at the mountaintops to improve biodiversity.

2. Edge1140. At 1140 m altitude an edge is created, where a central road is suggested. At this edge the high-rise buildings are concentrated in order to maximise the use of the road and to shorten the length of roads, cables and pipelines. In this zone rainwater is collected and stored. In the summertime the water is stored in basins and it can also be used as grey water in the high-rise buildings. In the wintertime rainwater is used in the high-rise or flows downhill. At high-rise buildings, green roofs are proposed to keep the water high on the hills.

3. Slope. The slopes, especially steep ones are not used for any building. They are kept green in order to improve the natural quality and biodiversity. Green slopes are also able to clean rainwater from roofs and roads in 'vertical wetlands'. At the bottom of the slopes this cleaned water is collected.

4. Valley1060. The edge of the valley can be used to store cleaned water from the slopes and collect rainwater, falling in this zone. In the summer rainwater is retained and used as grey water in low-density buildings, which are concentrated at the edge of Valley1060. Water from roofs and roads needs to be cleaned in wetlands. The cleaned water is stored in basins in summer, and is put through directly to the river in the winter. To keep the rainwater as long as possible in the area green roofs is used, the rainwater is infiltrated in the soil or the water is filtrated in sand-beds.

5. River. The edges of the river are the last possibility to clean rainwater from roads and roofs. If wetlands are projected here the water can be cleaned before entering the river. In the winter clean water is added to the river

If these principles are fit in the site (Fig. 2.33) the high-rise buildings are concentrated and positioned at Edge1140 and low-density buildings gathered at the edge of the valley. By doing so, larger areas stay free from building activities and the biodiversity and the quality of green space is improved. Moreover, it increases the possible use of space for water retention. Last but not least it creates a free ecological zone alongside the river, very important as a base for ecological development.

In more detail, the concept is designed for a distinct water-catchment area (Fig. 2.34). The hilltop is reserved to grow a forest. Water is kept here to supply the trees. At Edge1140 the high-rise is concentrated around the horizontal road and surrounded by ponds (to collect and store rainwater) and reed beds (to clean roof and road water). The steepest slopes are planted with native plants and prevent the slopes from erosion. In Valley1060 the low-density buildings are gathered and are accompanied by wetlands (to clean roof and road water) and ponds (to retain rainwater before it enters the river). The river valley is mostly kept free of buildings -it only contains the Shui Dong Road and the business units for headquarters -in order to give room to ecological processes alongside and inside the river. The ecological banks are functioning as a green zone, where native wildlife has the chance to develop. There is some co-use possible in this area. For instance, extensive recreation, traffic on bikes or by foot and hot springs may be introduced in this zone.

2.9.2.6 The 'Cake': Concentrating Building Densities

The result of implementing the concentrated building concept is that the landscape regenerates its original quality and beauty. Distinct building zones are mixed with specific green areas. The mountain is as a cake (Fig. 2.35), has a crown around the top and a collar at the bottom.

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