This project uses a combination of whole watershed discharge measurements, observations of nutrient fluxes within riparian forests, and landscape modeling to study the effects of geochemistry, land use distributions, and weather on watershed discharges of nitrogen and phosphorus to Chesapeake Bay. Comparisons of discharges from watersheds in the three geological provinces of the Chesapeake watershed (Appalachian, Piedmont, and Coastal Plain) will examine the importance of regional geochemistry. Within each province, a comparison of discharges from watersheds with contrasting distribution patterns of cropland and forest will be made in order to quantify the variability of discharges within a province and to test the generality of the nutrient-filtering ability of cropside riparian forests previously observed on coastal plain watersheds. Multi-year data would be collected to gain insight into effects of weather variation. Fluxes of nutrients moving through cropside riparian forests will be measured and determine the spatial pattern of nutrient retention (particularly nitrate) within those forests. The importance of factors such as geochemistry, forest age, slope, and forest width will be evaluated. Landscape models of nitrate discharge from cropland/forest systems will be developed and used to predict landscape discharges by combining data on retention within forests with detailed information on the spatial distribution of forest relative to cropland, developed with the aid of a computer-based geographic information system (ARC/INFO). Model predictions will be compared with spatial data at different levels of resolution in order to evaluate model performance and develop recommendations for regional efforts to model discharges to the Chesapeake. The investigators are well qualified to do this type of research, and the institutional support is excellent.
