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Streamflow Flashiness in the Mid-Atlantic Region: A Historical Analysis of Flashiness and Population Density, Imperviousness and Urban Development
Citation:
JARNAGIN, S. Streamflow Flashiness in the Mid-Atlantic Region: A Historical Analysis of Flashiness and Population Density, Imperviousness and Urban Development. Presented at 2008 Science Forum, Washington, DC, May 20 - 22, 2008.
Impact/Purpose:
Presentation
Description:
The relationship between stream flashiness and watershed-scale estimates of percent imperviousness, urban development, and population density were used in an historic landscape analysis at the individual watershed spatial scale. GIS technology was employed to spatially associate data layers for analysis: population density for 1930-2000; urban development circa 1973, 1992, and 2001; and the percent imperviousness (for 1992 and 2001) for a set of 150 small (< 130 km2) watersheds with long-term (> 20 years) USGS NWIS historical daily mean streamflow datasets in the mid-Atlantic, USA. Streamflow stations that showed significant changes in historical flashiness had a higher mean population density than those that showed no change. The empirical data provide support for a historic development pattern of approximately 10% imperviousness and/or 20% urban development without significant changes in stream flashiness. The historical data suggest that increasing degrees of development intensity beyond this point do significantly alter streamflow. One use of this dataset is to search for 'positive outliers' - where predicted stream flashiness is less than anticipated by the level of urban development. Detailed examination of these watersheds may yield examples where BMPs or patterns of development have been successful at mitigating the impact of urban development on stream hydrology.