A new USGS study examines effects of urban development on stream ecosystem health. Findings show that aquatic insect communities demonstrate little, if any, initial resistance to low levels of urban
development that were previously thought to be protective of aquatic life. By the time a watershed reaches about 10 percent impervious cover in urban areas, aquatic insect communities are degraded by as much as 33 percent in comparison to aquatic insect communities in forested watersheds.
Comparisons among the nine metropolitan areas show that not all urban streams respond in a similar way. Land cover prior to urbanization can affect how aquatic insects and fish respond to urban development and is important to consider in setting realistic stream restoration goals in urban areas.
The USGS determined the magnitude and pattern of the physical, chemical, and biological response of streams to increasing urbanization and how these responses vary throughout nine metropolitan areas, including Portland, OR; Salt Lake City, UT; Birmingham, AL; Atlanta, GA; Raleigh, NC; Boston, MA; Denver, CO; Dallas, TX; and Milwaukee, WI.
For more information, including access to USGS reports and video podcasts, please visit http://water.usgs.gov/nawqa/
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