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Sustainable Urban Environmental Planning - Community Plans
IDENTIFYING LANDSCAPE STRUCTURE ZONES - A BASIS FOR URBAN ENVIRONMENTAL PLANNING AT THE LOCAL LEVEL
Any city can be sub-divided into a series of distinct Landscape Structure Zones; these can be thought of as the basic building blocks of the city. They are readily identifiable with the aid of the colour air photographs as they show up as pattern changes on the ground. Except for those areas of cities which have undergone redevelopment, the Landscape Structure Zones are those areas of land within which there is a high level of homogeneity in the pattern of the built form and its associated landscape. These patterns reflect the choice made by the different developers within the constraints of the local natural and physical environment as well as social and economic circumstance as each settlement expanded. For instance, as we walk through any city we are aware of sudden changes in the 'picture' we see: - a densely built area with rows of houses each with small front gardens will suddenly give way to an area of larger row houses with no front gardens and that in turn to an area built over by semi-detached houses spaced at equal distances apart and with front and rear gardens full of trees. These are the Landscape Structure Zones and the range of possible 'urban landscapes' that results is immense. The zones are not just a result of variations in the major land uses across the city as there are substantial landscape character variations within each land use. The differing urban landscape characteristic are a result of the way each area of land has been laid out; the styles and fashions of design when that occurred and the underlying natural, social and economic processes. As a result, different housing, industrial or open space areas within a city can have very different impacts on the local level of environmental sustainability. The detail of the built form and the local environmental and social circumstances within each Landscape Structure Zone determines how well each supports different lifestyles and, therefore, influences the local quality of life. Therefore, to record such details creates an effective environmental database for sustainable urban planning; it also allows the development of local environmental monitoring systems in relation to sustainability of land use and land management. The cause of the variations between urban Landscape Structure Zones across a city, are the same everywhere: whenever development takes place someone or some authority has decided how the land will be divided up, how the roads aligned, which natural features will be retained, etc.. These decisions alone distinguish one part of a town from another and also the impact of the specific characteristics within each zone on local environmental and social sustainability. If the development is low density individual private houses the level of uniformity in built form within a zone might be minimal only relating to the allocation of plots and roads, but there is still likely to be some uniformity in the layout, use and management of the outdoor spaces. However, in most cases of modern urban development, decisions are made for a substantial group of dwellings by developers or planners over a relatively short period of time. These decisions predetermine the density, form and height of each building, its materials, its energy efficiency, its pattern of water usage, its garden size, its relationship to roads and footpaths, the distribution of local open spaces and often the plants which grow in the gardens. Such initial decisions will also have an effect on whether pre-existing vegetation is retained and incorporated into the new development, whether streams are kept open or culverted or whether new planting is added or not and, therefore, even on the level of biodiversity that can ultimately be supported. These decisions determine to a major extent the relative sustainability of the local built form. Therefore, holding data on the different Landscape Structure Zones across a city provides a tool both to examine relative sustainability and to use when planning remedial actions in areas of existing built form. Identifying the Landscape Structure Zones* of any settlement is proving a useful tool in a variety of circumstances, but particularly where it is considered important to examine the relative environmental sustainability of existing built up areas. A recent example is the work on sustainability carried out by the Danish Building Research Institute (SBI)**. The Danish work has shown that, once a study area is divided into its component Landscape Structure Zones, these can act as the basic units for first recording and then assessing the importance to local environmental sustainability of a range of abiotic and biotic data as well as of local actions in relation to energy and water conservation and waste management. The zones can also be used to examine variations across a community resulting from the interaction between environmental and social and economic data. These zones are particularly useful to the development of local environmental planning techniques as their level of homogeneity allows sampling techniques to be applied; this considerably speeds up the work of making an environmental database. The zone boundaries can be used to map units against which data can be held within a Geographic Information System. Data can be held for the zones on a wide range of factors such as: slope and aspect, micro climate variations across a site, local drainage patterns, the percentage of the surface covered by vegetation of different types, the size of gardens, the percentage of unpaved surface, land and landscape management regimes, the age and condition of buildings, housing tenure, assessments of ecological and of visual value etc.. You will need to decide what it is appropriate to record and examine locally. Although the process is mainly useful for local environmental planning it can also be used on larger site planning projects.
* The homogeneous units, described here as Landscape Structure Zones, have been termed elsewhere Urban Structure Zones. Zones like this were first used in the 1980s by the landscape planners and ecologists at the Technical University of Munich. See Pauleit,S. and Duhme,F.(1995): Umweltqualitätsziele und Naturschutzkonzepte auf der Grundlage von Strukturtypen am Beispiel der Stadt München. Stadtökologie in Sachsen, Leipziger Symposium. Sächs.Staatsministerium für Umwelt und Landesentwicklung, Dresden. ** The SBI has funded research at the local level into the link between land and landscape management within built up areas and the level of environmental sustainability achieved within differing built forms. See Attwell,K. ed (1999),Sustainable planning and management of green space, Danish Building Research Institute, SBI, Horsholm, Denmark or Website http://www.arbeer.demon.co.uk
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Sustainable
Communities - local action |
