• N. J. Snyder,

  • S. Mostaghimi,

  • D. F. Berry,

  • R. B. Reneau,

  • S. Hong,

  • P W. McClellan,

  • E. P. Smith

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      Respectively, Project Engineer, Waterborne Environmental, Inc., 847–13 Harrison St., S.E., Leesburg, Virginia 20175 (former Graduate Student); Professor, Biological Systems Engineering Department; Associate Professor and Professor, Crop and Soil Environmental Science Department; Research Associate and Systems Analyst, Biological Systems Engineering Department; and Professor, Statistics Department; Virginia Polytechnic Institute and State University, 308 Seitz Hall, Blacksburg, Virginia 24061.

  • 1

    Paper No. 96132 of the Journal of the American Water Resources Association. Discussions are open until December 1, 1998.


ABSTRACT: A field monitoring study of a riparian forest buffer zone was conducted to determine the impact of the riparian ecosystem on reducing the concentration of agricultural nonpoint source pollutants. Groundwater samples were collected from 20 sampling locations between May 1993 and December 1994, and analyzed for NO3-N, PO4, and NH4-N. Statistical analyses such as Friedman's test, cluster analysis, cross correlation analysis and Duncan's test were performed for the nutrient data. The study showed that the ripanan buffer zone was effective in reducing nitrate concentrations originating from upland agricultural fields. Instream nitrate concentrations were 48 percent less than those measured in the agricultural field. Reductions in concentrations in sampling locations at the wetland edge ranged from 16 to 70 percent. The mean nitrate concentrations in forested hill slope were 45 percent less than concentrations in a well located in an upland agricultural field. Meanwhile, the concentrations of phosphate and ammonia did not follow any specific spatial trend and were generally higher during the summer season for most sampling locations.