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Title: QUANTIFICATION OF URBANIZATION IN EXPERIMENTAL WATERSHEDS

Author
item Bonta, James - Jim
item SHUSTER, WILLIAM - USEPA
item Pappas, Elizabeth
item THURSTON, HALE - USEPA
item Smith, Douglas
item GOSS, MICHAEL - USEPA
item CABEZAS, HERIBERTO - USEPA

Submitted to: First Interagency Conference on Research in the Watersheds
Publication Type: Proceedings
Publication Acceptance Date: 10/23/2003
Publication Date: 10/23/2003
Citation: Bonta, J.V., Shuster, W., Warnemuende, E.A., Thurston, H., Smith, D.R., Goss, M., Cabezas, H. Quantification of urbanization in experimental watersheds. Proceedings of The First Interagency Conference on Research in the Watersheds. Benson, AZ. Oct. 27-30, 2003. p. 355-363.

Interpretive Summary: Although urbanization has a major impact on watershed hydrology, there have not been many studies to quantify how basic hydrology is altered by the addition of impervious surface under controlled conditions. The USDA-ARS and USEPA have jointly initiated a pilot program to study the impacts of simulated impervious surfaces on hydrology, sediment, and water quality in small experimental watersheds located at the North Appalachian Experimental Watershed, Coshocton, OH. This paper outlines the approach and rationale for using rainfall simulation, experimental watersheds subjected to natural precipitation and weather, and modeling for a multiyear project. Percent of the area of each watershed that is impervious is planned form 0% to 40% under two spatial arrangements of imperviousness ' impervious areas that are connected to stream channels and impervious areas that are not connected to stream channels will be studied. The results from laboratory rainfall simulation will help guide the implementation of impervious surfaces in the watersheds. Preliminary evaluation of the Coshocton baseline runoff data shows that, during the time of constant land use since 1975, annual runoff depths are similar and runoff regimes have been constant. This allows the comparison of runoff data collected after imperviousness is installed with the preexisting runoff record. Results from this study are applicable to the development of urban hydrology analyses, hydrology and water-quality models, design and testing of urban best-management practices, and environmental management. Regulatory entities and researchers will benefit from the results of this study.

Technical Abstract: Although urbanization has a major impact on watershed hydrology, there have not been many studies to quantify how basic hydrological relationships are altered by the addition of impervious surface under controlled conditions. The USDA-ARS and USEPA have jointly initiated a pilot program to study the impacts of simulated impervious surfaces on hydrology, sediment, and water quality in small experimental watersheds located at the North Appalachian Experimental Watershed, Coshocton OH. This paper outlines the approach and rationale for using rainfall simulation, experimental watersheds subjected to natural precipitation and weather, and modeling for a multiyear project. Percent imperviousness is planned from 0% to 40% under two spatial arrangements of imperviousness - stream-channel-connected and stream-channel unconnected imperviousness. The results from laboratory rainfall simulation will help guide the implementation of impervious surfaces in the watersheds. Preliminary evaluation of the Coshocton baseline runoff data shows that, during the time of constant land use since 1975, annual runoff depths are similar and runoff regimes have been constant. Results from this study are applicable to the development of urban hydrology analyses, hydrology and water-quality models, design and testing of urban best-management practices, and environmental management. The data and results of this project will be used for improved modeling, BMP development and evaluation, and as data bases for a national tradable runoff credits program. Users of results from this project include USEPA, ARS, and university scientists, environmental regulators, engineers, hydrologists, landscape architects, and governmental officials involved in establishing guidelines for minimizing the impacts of urbanization.