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URBAN/SUBURBAN WATERSHED CHARACTERIZATION
Impact/Purpose:
Develop and test small watershed scale methods to identify potential hazards to streams from urbanization processes, including methods to quantify the current amount of impervious cover and project possible impervious cover levels in the near future. Apply the best methods developed to estimate impervious cover throughout Region IV. Test the utility of landscape metrics as indicators in Piedmont watersheds.
Description:
The ability to characterize the land surface and related pollutant source loadings is critical for reliable watershed modeling. Urban/suburban land uses are the most rapidly growing land use class, generating non-point source pollutant loadings likely to seriously impair streams. While intensively developed urban areas and characterization of the outlets from their storm and waste water treatment systems have received significant attention, less effort has been expended in delineating pollutant loadings from lower density developed land uses and the impacts therein of management practices in the more suburban areas. Previous investigations demonstrated that use of mean satellite characterized land cover data does not adequately identify suburban land use, or serve to adequately estimate impervious cover. Percent impervious cover is both a useful indicator of watershed condition and a critical input for hydrologic models. Interpretation of aerial photographs will be used to develop test data sets to develop and evaluate estimates of impervious cover and turf grass area. The uncertainty of using land cover and other regionally available data sources to estimate pollutant loading from suburban systems will be assessed. A review of studies measuring constituent pollutant loads from suburban systems will be developed, existing estimation techniques evaluated, knowledge gaps and critical information needs identified. Small scale surveys or field studies may be undertaken to fill critical data gaps. New methods for pollutant source estimation and evaluation of impacts of alternative development patterns will be developed. Existing in-stream water quality and biological sampling data will be used to evaluate how well landscape watershed indicators identify impaired stream function. Other regional indicators related to environmental stress per unit of economic output will be evaluated.