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CONCENTRATIONS AND ESTIMATED LOADS OF NITROGEN CONTRIBUTED BY TWO ADJACENT WETLAND STREAMS WITH DIFFERENT FLOW-SOURCE TERMS IN WATKINSVILLE, GEORGIA
Citation:
SCHROER, K., D. M. ENDALE, C. T. STEVENS, J. W. WASHINGTON, AND V. NZENGUNG. CONCENTRATIONS AND ESTIMATED LOADS OF NITROGEN CONTRIBUTED BY TWO ADJACENT WETLAND STREAMS WITH DIFFERENT FLOW-SOURCE TERMS IN WATKINSVILLE, GEORGIA. Presented at Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Impact/Purpose:
Improve the scientific understanding of the processes controlling nutrient distributions in surface waters. Produce a suite of enhanced models for characterizing nutrient distributions in surface waters by incorporating improved process understanding in existing models (e.g., WASP), by developing new models (e.g., WHAM, reactive transport), and improving linkages between model components.
Description:
Inorganic, fixed nitrogen from agricultural settings often is introduced to first-order streams via surface runoff and shallow ground-water flow. Best management practices for limiting the flux of fixed N to surface waters often include buffers such as wetlands. However, the efficacy of wetlands to immobilize or reduce nitrate depends on several interacting local conditions that are not well understood. At the USDA-ARS, J. Phil Campbell Sr. National Resource Conservation Center in Watkinsville, Georgia, two adjacent streams (14m apart at head-cut) in a wetland depression provide drainage for an upland pasture for beef cattle. One of the streams is protected from surface run-off by a man-made berm and has a flowing spring at its head-cut. The other stream is not protected from runoff and does not have a conspicuous spring. Due to the different flow-source terms, chemical-species distribution is very different in the two adjacent stream channels. This research is part of a larger study in which in-stream processes are being evaluated to account for N loss along each channel. However, quantifying the individual nitrogen species and total N loadings contributed by each of the two channels will shed light on the importance of specific wetland hydrological and geochemical conditions to delivery of fixed N from agricultural settings to receiving waters.