ABSTRACT
A recent definition of urban sustainability offered at the Sustainable City Conference in Rio (2000) stated that
Urban development is a major consumer of land. Natural landscape areas around the cities are converted into housing estates, industrial parks, and other kinds of facilities designed to serve the community. Land is typically used for housing, businesses, industry, surface and subsurface infrastructures such as roads, wastewater supply, sewers, and power lines, and recreational purposes such as parks and playgrounds. In the U.S., it is estimated that about 100 m
of land/sec is lost to urban uses; Germany loses about 14 m
/sec, and Switzerland, a more environmentally aware country, loses about 1 m
/sec (RSU, 2000
)
. Abandoned industrial lands are not included in the estimates. In the urban context, surface and subsurface soils may be contaminated and degraded.
