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- Info
Urban stormwater runoff contamination of the Chesapeake Bay: Sources and mitigation
| Author: |
Cohn-Lee, Richard G.; Cameron, Diane M. |
| Date: |
1992 |
| Periodical: |
The Environmental Professional |
| Abstract: |
A runoff modeling system incorporating urban land use, annual rainfall, and storm water concentration data for selected heavy metals, nutrients, and organics, has been applied to the following urban areas in the Chesapeake Bay region: Harrisburg, PA, Baltimore, MD, Washington, DC, and the Hampton Roads region of Virginia. Annual quantities of pollutants are compared to area and statewide point source discharges from sewage treatment plants and large factories. Data indicate that contamination of the Bay and its tributaries from runoff is comparable to, if not greater than, contamination from industrial and sewage sources. An examination of the Chesapeake Bay 40 percent nutrient reduction goal focuses on the stormwater management programs of Montgomery and Prince George's counties in Maryland. Based on a land-use analysis for 1985 and 1990 and an inventory of stormwater management devices in both counties in 1990 nutrient reductions are estimated and compared to the Chesapeake Bay year 2000 nutrient reduction goal. A comparison between increased runoff, primarily from sprawl development, and treatment achieved by stormwater control devices shows a net increase in nutrient loadings from 1985 to 1990 within the urban sector, indicating that control of growth, instead of sole reliance on "end-of-pipe" devices, is necessary. Growth control strategies include high-density cluster zoning and the establishment of caps on impervious surfaces within watersheds. A comparison between nutrient contributions from urban and agricultural sectors in both counties shows that, for nonmanured farmland, urban runoff either outweighs or, at a minimum, is the same order of magnitude as agricultural runoff as a source of nutrients to the Bay. |
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