Hydro-ecological implications of edge cities

A spatial and temporal classification of the embryonic forms of edge cities within their physical/environmental context is developed. Three classes of edge cities are identified as having developed along the expressway system: (1) transportation/service; (2) transportation/service/commercial; and (3) corporate/industrial. Each edge-city class has special implications for the hydro-ecological environment. A case study was used to assess the effects on these three classes on several basic indicators of impacts from stormwater runoff, groundwater contamination, and habitat fragmentation. The results indicate that transport/service edge-cities may pose a significant threat of contamination to the groundwater resource owing to the existence of underground storage-tanks and the transport of hazardous substances. In transport/service/commercial edge-cities, runoff volumes increase dramatically and water quality declines, as development displaces wetlands and creates impervious land cover. At a corporate/industrial edge-city location, habitat fragmentation is higher, as reflected by a decreased patch size for forest and wetland areas.