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United States Department of Agriculture

Agricultural Research Service

Title: In-Stream Wetland Mitigation of Nitrogen Contamination in a Usa Coastal Plain Stream

item Stone, Kenneth
item Hunt, Patrick
item Humenik, F - NC STATE UNIV.
item Matheny, Terry
item Johnson, Melvin

Submitted to: Constructed Wetlands for Animal Waste Management Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 9, 1999
Publication Date: N/A

Technical Abstract: Nonpoint source nitrogen (N) from in-streams and rivers is a major water quality problem throughout the world. Nitrogen removal from a contaminated stream was evaluated in this study using an in-stream wetland (ISW). The ISW was established at the exit of a 425-ha USDA Water Quality Demonstration watershed in the Coastal Plain of North Carolina. It ranged in depth from about 0.2 to 2 m, and it was less than 1% (3.3 ha) the size of the watershed. The ISW dramatically lowered mean stream nitrate-N from 6.6 to 2.0 mg/L. Nitrate-N mass removal was highly correlated to inflow nitrate-N (r = 0.93) in the warmer months when biological processes were more active. Ammonia-N mass removal was opposite that of nitrate-N. It was highly correlated to inflow ammonia-N (r = 0.81) during the cooler months. Total annual N removal for the ISW was approximately 3 kg/ha/day, which was about 37% of the inflow N. The ISWs appear to be very good landscape features for mitigating excess nonpoint source N in the southeastern Coastal Plain of the USA and should be a good complement to other best management practices for improved water quality.

Last Modified: 4/21/2015
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