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UF Researchers: Man-Made Wetlands Can Help Urban Farms Treat Runoff

Aaron Hoover

Roger Nordstedt (352) 392-7786
Mary Sowerby (813) 744-5519

GAINESVILLE — An environmentally friendly solution to farm runoff could help dairymen survive in an increasingly urban and regulation-filled world, say University of Florida researchers.

Currently undergoing a trial run on a small farm in the Hillsborough County community of Temple Terrace, the artificial wetland showcases a relatively low-cost, effective way to treat runoff at a time of tightening environmental regulations for dairy farms in urban areas, said Roger Nordstedt, a professor of agricultural and biological engineering.

“These small dairy farms are being forced out by urbanization and the toughened environmental regulations and restrictions that come with it,” Nordstedt said. “I think other farms in the Hillsborough County area and statewide may be able to use this method as a cost-effective way to manage their runoff.”

The recently completed system is up and running, but Nordstedt must take measurements over several months before determining how well it is cleaning the runoff. Early indications, however, are good, he said.

Hillsborough County has at least 10 small dairies, and there are as many as 20 others in urban areas elsewhere in the state, officials said. Most of the Hillsborough County dairies likely could use the artificial wetlands system, said Jemy Hinton, an environmental specialist and agriculture liaison at the Florida Department of Environmental Protection in Tampa.

Nordstedt and Mary Sowerby, a multicounty dairy extension agent with UF’s Institute of Food and Agricultural Sciences, head up the project, which is being paid for with a $69,000 grant from the DEP.

The artificial wetlands were built this year at the 270-cow Maple Lane Dairy, a 56-year-old dairy that once existed in open countryside. Since the farm was built, however, numerous roads, including U.S. 301 and Interstate 4, have cut into its property, as has an industrial complex on the west side of U.S. 301.

The wetlands add an extra layer of treatment to runoff created as part of the farm’s routine daily operations, Nordstedt and Sowerby said.

Workers remove much of the farm’s solid waste and send it to a company that turns it into compost. But they also hose down the cow holding pens and milking parlor, and the runoff flows into the first of three ponds known as treatment lagoons. Maple Lane uses the lagoons, as do most Florida dairies, for storage and treatment of waste water.

Years ago, the runoff from the third lagoon flowed into nearby Six Mile Creek. However, construction of the Tampa Bay Bypass Canal replaced the creek. Because the canal is a source for Tampa area drinking water, local environmental officials became concerned about the lagoon runoff damaging the water quality.

In response, the owners of the farm decided to try treating the lagoon water with the wetlands system. The family was the first in Hillsborough County to install the lagoon system, said Ronnie Aprile, whose family owns and operates Maple Lane Dairy.

The system consists of two separate constructed wetlands measuring a total of about an acre. Each wetland has plants, including pickerel weed and arrowheads, that soak up nutrients. Runoff flows from one wetland into the other, and then across a sloped grass field. Any remaining runoff drains into a ditch and is pumped back into the first wetland.

“The bottom line is, we’re trying to get these nutrients utilized by plants instead of left in the water where they can contribute to algae blooms or other things,” Sowerby said.

The wetland also will help in other ways. When the pickerel weed and arrowheads reach healthy population levels, they will be harvested and used elsewhere in new artificial or natural wetlands, Hinton said.

Hinton said farms have a high economic impact on communities, so it’s important to help them flourish while ensuring they don’t pollute. “We want to make these folks get into compliance with environmental regulations but still afford to stay in operation,” she said.