Under sprawl refers to either the construction of buildings outside "related built" districts in or the unregulated and unstructured growth of towns in the undeveloped area. Sprawl is, on the one hand, a partial aspect of suburbanization (English: urban sprawl ), which describes the spread of monofunctional, sparsely populated and individual traffic- dependent zones on the outskirts, and on the other hand, a broader term, as it not only describes the peripheral growth of agglomerations , but also the urban sprawl z. B. in touristically interesting regions. Mostly the term urban sprawl is used to describe the negative effects of this process, as the prefix “Zer-” already suggests; However, like the term urban sprawl, it is vaguely defined, difficult to operationalize and its delimitation is controversial.
As part of the National Research Program NRP 54, researchers from Switzerland have defined urban sprawl as follows: Urban sprawl is a phenomenon that can be visually perceived in the landscape . A landscape is more sprawled, the more area is built up, the more widely scattered the settlement areas are and the less it is used for living or working purposes. The measurable criteria of size, distribution and use of the settlement area thus complement the intuitive assessment of urban sprawl. This definition can be used to quantify development trends in urban sprawl.
What all forms of urban sprawl have in common is the land consumption due to the growth of settlement areas into the landscape. Due to large-scale urban sprawl, cities and landscapes are in a fundamental process of change. In particular, the surrounding areas of large cities are changing their natural or cultural character. This trend towards the increased formation of fat belts has been observed in Germany for decades.
According to the “ Anthrome ” model published in 2008 by the two American geographers Erle C. Ellis and Navin Ramankutty , around half of all people worldwide live in the dense settlements (villages) of metropolitan areas .
Was promoted significantly and urban sprawl the landscape due to high price of land in cities, by the local urban land (on the edge of the settlements) and the solidification of splitter settlements in the outer region. Rising incomes are driving young families in particular to realize the dream of their own house in the country without having to give up their job in the city. But wealthy pensioners are also moving to the suburban areas. The distribution of the car makes the spatial separation of work and sleep space more attractive and allows the establishment of businesses outside the city limits . The state favoring the separation of work and place of residence through the distance lump sum as well as undifferentiated housing construction subsidies are named as causative and beneficial for urban sprawl. The establishment of industrial parks and large shopping centers on the edge of settlement areas also promotes urban sprawl; it is justified with the creation of jobs and income for the communities.
In rural areas, in the villages , urban sprawl is favored by the reallocation of arable land to building land, despite the building land still available in the core area. The design of the settlements using the open construction method also has an impact on the consumption of the landscape.
Urban sprawl is also criticized for its traffic-generating effect. Public transport requires high population density and usage density in order to be profitable. Residents of suburbs are mostly dependent on motor vehicles because of the declining supply and demand for public transport . Some measures to help curb negative sprawl symptoms, such as: B. Park-and-ride , can make these even more attractive and speed up. The concept of supplying existing demand , which is widespread in transport policy , is also controversial , since road construction in turn leads to new demand in many cases.
One of the most controversial consequences of urban sprawl is its negative impact on the social fabric and quality of life . Since zones with low population density and satellite cities are often unable to provide a wide range of services , there is often a lack of public facilities such as libraries , swimming pools , higher schools or day-care centers . The residents are forced to travel long distances for most activities. It comes to the exclusion of residents to not be able. Minors, disabled , elderly or socially disadvantaged people are particularly affected .
The situation is often aggravated by the fact that the street , which also functions as a kind of platform for public coexistence in urban areas, degenerates into a pure transport artery in urban sprawl and acts more as an additional barrier. The high level of dependency on cars endangers the health of the population, as drivers cover fewer distances on foot or by bicycle and are therefore more likely to have a lack of exercise and the general concentration of pollutants in the air they breathe increases many times higher than when they use public transport. The outflow of purchasing power from main urban streets to shopping centers can also lead to a desertification of the cityscape and a loss of diversity. Urban areas, which previously consisted of a mixture of social classes, are experiencing increasing segregation (simplified ghettoization ) due to the migration of richer residents to the suburbs , which can increase social tensions. But the formation of suburban ghettos, as can be observed particularly in France , can also be a consequence.
Special forms and trends
A special form of this development towards ghettoization is the increasing number of so-called closed residential complexes (e.g. country clubs , gated communities ), particularly in the USA , Great Britain and some developing countries, but also to some extent in other European countries. In many cases, these “private quarters” are built in scenic areas, have a high level of landscape consumption due to their large plots and promote segregation according to social class. In the cities of Great Britain, especially London , there are these controversial gated housing developments in neglected neighborhoods that are close to the attractive financial districts, but also have high crime rates.
The development of the telecommunications infrastructure and the Internet has led to a new paradoxical development trend since the 1990s. While rural areas are being increasingly integrated into the communication environment and previously urban jobs are being relocated here (“urbanization of the country” through “tele-villages” or outsourced office cities with call centers , etc.), many urban districts are being decoupled from economic dynamism and are losing their infrastructure and their urban quality. Unemployment and inadequate wages lead to urban agriculture , e.g. B. in the form of inner-city vegetable cultivation on desolate areas, the keeping of small livestock on the balcony or fish farming on the roof (so-called " ruralization of the city"). In Havana, 90 percent of all fresh products come from inner-city gardens.
On the other hand, an official resolution creates “urban” quarters that have no urban qualities from the start and force the residents to self-sufficiency, as was once the case in the Prussian industrial villages of Altenessen , Borbeck , Schalke , Sterkrade or in today's Chinese industrial villages with high-rise residential buildings, industrial facilities and extreme population growth rates (urban villages) . The number of urban villagers - as the inhabitants of such areas are called - is estimated at 50 to 100 million in China.
In Switzerland there are political forays to stop urban sprawl.
- Ronald Kunze, Hartmut Welters (ed.): BauGB Innovations 2007 . Comment on the innovations and legal text BauGB 2007 including BauNVO. WEKAMEDIA, Kissing 2007.
- Ronald Kunze: Urban sprawl. The sustainability strategy under discussion. In: Planner. Trade journal for urban, regional and state planning. H. 1/2004, p. 3/4.
- Juliane Lorenz: More Urban to Suburbia. Urban strategies to combat sprawl in the Toronto metropolitan area. In: Urban development - architecture - society. 1. 2010, ISBN 978-3-8382-0141-2 .
- Niklas Maak: residential complex. Why we need other houses. Hanser-Verlag, 2014, ISBN 978-3-446-24352-1 .
- Measuring urban sprawl (Federal Research Institute WSL)
- Building land - how Switzerland is sprawled (SRF)
- J. Jaeger, R. Bertiller, C. Schwick, F. Kienast: Suitability criteria for measures of urban sprawl. In: Ecol. Indic. 2010, 10, pp. 397-406. German translation of the definition: C. Schwick, J. Jaeger, F. Kienast: Measure and avoid urban sprawl. (PDF; 2.3 MB). In: Merkbl. Practice. 2011, 47.
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