ISU Ag Engineer Studies Innovative Ways to Control Feedlot Runoff

April 2nd, 2003

AMES, Iowa — An Iowa State University agricultural engineer is conducting research on innovative techniques livestock producers can use to comply with new federal regulations.

Jeffery Lorimor, associate professor in the ISU agricultural and biosystems engineering department, says although the alternative technologies he's studying "won't be a silver bullet, they will be new tools producers can use either alone or in combination."

The U.S. Environmental Protection Agency (EPA) developed the new rules governing concentrated animal feeding operations (CAFO) under the nation's Clean Water Act. More producers will need to apply for permits because large open feedlots and poultry operations now fall under the CAFO regulations. A bright spot in the new rules is the opportunity to establish what are called "voluntary alternative performance standards based on innovative technologies."

That's where Lorimor's work enters the picture. One research project involves an infiltration-wetland system. "The system captures feedlot runoff and forces it to infiltrate into the soil where many of the contaminants are removed," Lorimor said. "Tile lines under the infiltration basin collect the infiltrated water and what remains of the pollutants and carries them to a wetland."

Lorimor said the wetland does additional cleaning before the water moves through a grass waterway to the stream. "The waterway cleans up the flow further, even more than the wetland," he said. "In five years of research, we've proven a system of soil infiltration followed by wetland treatment significantly reduces contaminant concentrations and flow volume. Overall, the system provides better water-quality protection than total containment."

Lorimor is leading another research project that tests and demonstrates the effectiveness of vegetative filter strips (VFS). "We measure and sample flow above and below grassed areas below feedlots. This data will be used to help calibrate a VFS model we're developing," Lorimor said. "Once the models are ready, we can do site-specific comparisons and predict water-protection effectiveness."

A similar modeling project is helping determine the effectiveness of containment basins around open feedlots. "We reconstructed the model the Iowa Department of Natural Resources (DNR) alternative systems are based on. We can predict how much overflow occurs each year at six different sites in Iowa for each of five systems," Lorimor said.

The model shows that total containment isn't really total containment. "We can control most of the runoff from open lots by capturing it and holding it for land application. But the containments can overflow because of chronic rainfall and lack of acceptable days for pumping. If the containments go into the winter almost full, they overflow before enough drying days occur in the spring to pump them down," he said.

Lorimor said if DNR and EPA officials approve the two models he's developing, producers will be able to use them to select a system that will be the most effective at controlling runoff from their livestock operations.

These alternative technologies should save producers money. "Total containment comes in at about $50 to $100 per head. The alternative technologies will be significantly less," Lorimor said. "Another advantage is that alternative technologies are more passive, meaning they don't have to be pumped to prevent overflow."

Lorimor said although the alternative technologies he's researching work, are passive and less expensive, they still require good management. "Vegetative filter strips must be maintained so they don't channel. Wetlands have to be sealed. Infiltration systems only work on certain soils. And these alternative technologies will make a larger footprint on the ground than a containment basin," he said.

The next steps in Lorimor's work are to recruit additional feedlots as demonstration sites and finish the two models. Then state and federal regulators will decide if producers can use these alternative technologies to comply with the new CAFO rules.

Iowa already has in place regulations that meet or exceed many of the new federal standards. A group made up of environmental and farm group representatives will work with DNR and Iowa State University personnel to study the new federal rules and determine how they mesh with existing Iowa law. Iowa has up to two years to implement any changes.

Contacts: 

Jeffery Lorimor, Agricultural and Biosystems Engineering, (515) 294-9806
Susan Thompson, Ag Communications Service, (515) 294-0705