Abstract

Stormwater best management practices (BMPs) are installed to reduce the delivery of pollutants to surface waters. The objective of this study was to determine the stormwater NO₃-N, PO₄-P, and Escherichia coli (E. coli) reductions in a constructed wetland in Greenville, North Carolina. Water samples were collected at the inlet and outlet of the wetland before, during, and after 11 storms for NO₃-N, PO₄-P, and E. coli analysis. Treatment efficiencies for NO₃-N (69%) and PO₄-P (63%) exceeded the nutrient credit reductions assigned to stormwater wetlands (40% for both) in North Carolina. The E. coli (59%) and PO₄-P (63%) concentration reductions in the wetland were similar to the reduction in specific conductivity (62%), possibly because of sedimentation in the wetland that reduced the suspended and dissolved solids with adsorbed E. coli and PO₄-P. The relatively large size of the wetland (7% of drainage area), and below average rainfall likely contributed to the exceptional pollutant reduction efficencies.

This work is licensed under a Creative Commons Attribution 4.0 License.