Improving Farm Effluent Water Quality with a Constructed Wetland
[Image: Constructed Wetland]
E. P Millhollon, J. L. Rabb, R. A. Anderson and J. F. Liscano
Louisiana’s coastal waters, lakes, rivers and bayous are the lifeblood of the state, providing generations of its residents a way of life not only for economic survival, but also for year-round recreation, earning the state the well-deserved title of “Sportsman’s Paradise.”
Agriculture in Louisiana depends on fresh water; most notably in the numerous rice fields that are a landmark of the state. Recognizing the need to protect the state’s most precious natural resource, Louisiana’s agricultural producers have adopted several practices, such as conservation tillage, that help protect this valuable resource. Although these practices have, without doubt, helped reduce non-point source discharges from agricultural fields into the state’s water bodies, new practices may offer additional improvements.
One such practice is the use of a constructed wetland, since it has long been known that the biological and physical properties of natural wetlands are beneficial in improving water quality.
Louisiana State University AgCenter’s Red River Research Station consists of 573 acres of agricultural land in the Red River Basin of Northwest Louisiana. Approximately 400 acres of discharge water from the station flow to the southeastern corner where it then drains into the Flat River, less than one-third mile away. The Flat River has been designated as an impaired water body by the Louisiana Department of Environmental Quality (LDEQ), meaning that the water quality of this water body does not meet standards established by the department. The primary suspected source of impairment to this water body is agricultural runoff. The southeast corner of the station was therefore identified as an ideal location to investigate the potential of a constructed wetland for improving the water quality of discharge from agricultural fields.
The effectiveness of this system is being determined by sampling water at various points along the path of the system, from the point where runoff enters the wetland, to the point where it leaves. Specific objectives for this project include: (1) With the guidance of engineers from the USDA-NRCS, design and construct a wetland in the Red River Basin that will accommodate discharge from 400 acres of agricultural land; (2) Determine the efficacy of a constructed wetland in improving water quality of agricultural discharge prior to entering an impaired water body. Those constituents suspected of causing impairment to the Flat River will be examined at stages to ascertain the efficacy of the system; and (3) Develop and implement an educational outreach program to inform agricultural producers of the benefits that can be derived from the construction of a wetland.
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