This 12-acre constructed wetland provides wildlife habitat for migrating waterfowl and a nesting area for animals. Photographer: Jason Johnson. Photo Courtsey of USDA NRCS.
Temperate, Semiarid, Tropical
North America, Europe, South America, South Asia, Africa
Nitrogen, Phosphorus, Sediment
Constructed wetlands, sometimes called treatment wetlands, are man-made systems engineered to approximate the water-cleaning process of natural wetlands. These artificial wetlands capture and filter runoff from cropland, feedlots, aquaculture operations, agricultural processing facilities, and urban stormwater. They effectively remove excess nutrients, sediment and other pollutants from surface runoff. 2
Constructed wetlands will require land to be taken out of production, but agroforestry and water-based crops for fiber, food, and fodder can partially offset these costs. In an urban context applicability of this BMP will depend on availability of suitably sited land. In an aquaculture context, wetlands are not suitable for treating the entire volume of an aquaculture pond because of the need to retain water for at least two days, but this option may be appropriate to treat the concentrated effluents typically associated with the final 10 percent to 20 percent of pond volume during draining. Implementation costs can be high and maintenance costs for constructed wetlands can be substantial. Over long term, wetlands can be very cost effective for reducing nutrients if properly designed and maintained.
Scalable to small farms?
1 Miller, T. P. , J. R. Peterson, C. F. Lenhart, and Y. Nomura. 2012. The Agricultural BMP Handbook for Minnesota. Minnesota Department of Agriculture.
2 Miller, T. P. , J. R. Peterson, C. F. Lenhart, and Y. Nomura. 2012. The Agricultural BMP Handbook for Minnesota. Minnesota Department of Agriculture.; 17. "EU Database of Best Practices." Living Water Exchange: Promoting Replication of Good Practices for Nutrient Reduction and Joint Collaboration in Central and Eastern Europe. Web. Sept. 2013. http://nutrient2.iwlearn.org/nutrient-reduction-practices/eu-database-of-practices/view.