Evaluation of an In-Stream Constructed Wetland
Introduction
The east coast of North Carolina has depended on drainage
canals to carry runoff from the flat landscape away from homes and agricultural
fields for many years. Town growth and urbanization has drastically increased
the load on these canals. More roads, shops, and parking lots
mean more stormwater runoff and more water these canals must carry.
These drainage waters also come in contact with a variety of contaminant
sources. Drainage waters can be exposed to nutrients and pesticides
from agricultural fields and lawns, oil and grease from roads,
parking lots, and other pollutants from septic tank systems, solid waste
storage and processing sites, and commercial properties.
Fish kills, shellfish contamination, and bacteria discoveries in N.C. has
made developing new ways to protect our water sources a priority. One
method that has excellent potential for controlling water flows and
enhancing water quality is wetlands. Wetlands use a combination of
physical, biological, and chemical processes to act as natural water
filters, removing and converting pollutants into less
harmful forms. Wetlands also support a wide variety of plants
and animals.
This wetland was constructed to intercept and cleanse drainage waters
that are exposed to a variety of pollutant sources before the waters
flow into the Albemarle Sound. The wetland will serve to reduce pollutant
levels as well as control the flow of water through the area. Research
conducted will determine how effective this wetland is for enhancing water
quality and controlling flows. It will also help develop proper methods
for future wetland design and construction.
Research
Water flow measurements were made at the two inlet streams and
the wetland outlet using continuous
water level recorders. These recorders operate using a pulley/float
mechanism and the data is recorded by a microprocessor. Automatic
water samplers are also located at each inlet stream and at the
outlet. These samplers provided data on the quality of the water at
various intervals. Manual samples are taken at six locations throughout
the wetland. Water quality samples are being analyzed at N.C. State's Soil
Science laboratory for sediment and nutrients(TKN, NH4,
NO3, TP, OP, & pH). Other monitoring included measurements
of dissolved oxygen and water temperatures.
Acknowledgements:
This research is being conducted by the North Carolina Agricultural Research
Service and North Carolina
Cooperative Extension Service ) with technical assistance and cooporation
provided by USDA Natural Resources
Conservation Service (NRCS) and the Albemarle Resource Conservation
and Development Council, Inc. with financial assistance provided by a grant from
the North Carolina Department of
Environment and Natural Resources Water Quality Section through
the 319(h) Nonpoint Source
Program and the Town of Edenton.
The principle investigators of this project are
Dr. Robert
Evans,
PhD
Dwane Hinson
Department Extension
Leader
District Conservationist
Department of Biological and Agricultural
Engineering, NCSU
NRCS
Kristopher Bass,
EIT
Rodney Johnson
Master's Degree
Candidate
Albemarle Resource Conservation and Development
Department of Biological and
Agricultural Engineering, NCSU
mailto:klbass@eos.ncsu.eduphone-(919)833-5682