Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 1996
Publication Date: N/A
Technical Abstract: An in-stream wetland that was established by beavers in eastern North Carolina has improved stream water quality from a small agricultural watershed. The wetland, which is located at the outlet of a 425-ha watershed, is only 3.3 ha. Yet, it has consistently lowered stream nitrate-N during warm months. Nitrate-N entering the wetland had a mean concentration of about 7 mg/ha which was lowered to less than 1 mg/ha during the warmer months by the wetland. Much of the nitrate-N was removed in the initial portion of the wetland. Chloride concentrations were not similarly lowered. Ammonia-N and ortho-P were also lowered, but not so dramatically. Nitrate-N was reduced to a smaller extent during the colder months. This annual cycle of lowered nitrate-N concentrations has occurred each year since the wetland was established in 1993. Loss of nitrate-N removal capacity during the winter is likely related to the lowered levels of denitrification and plant uptake. Where landscape features allow the presence of natural or constructed in-stream wetlands, they appear to have the capacity to significantly improve stream water quality.