A federal jury in Boise on Wednesday found Mike Vierstra, 52, of Twin Falls, Idaho, guilty of a negligent misdemeanor violation of the Clean Water Act (CWA), U.S. Attorney Wendy J. Olson announced. Vierstra was charged on October 13, 2010, with the negligent discharge of wastewater from a Concentrated Animal Feeding Operation (CAFO) into a federally protected waterway. He did not have a permit for such discharges.

Vierstra faces a maximum sentence of one year in prison, a $100,000 fine, and one year of supervised release. Sentencing is scheduled for June 6, 2011, in Boise, before U.S. Magistrate Judge Ronald E. Bush.

This case is part of EPA's National Enforcement Initiatives as it relates to “Preventing Animal Waste From contaminating Surface and Ground Waters” from CAFOs. Vierstra Dairy's operation includes about 1,200 animals.

“Large farms and dairies can cause serious damage to the environment through the illegal discharge of wastewater,” said Tyler Amon, Special Agent in Charge of EPA's criminal enforcement program in Idaho. “Yesterday's guilty verdict demonstrates that farm owners and supervisors will be held responsible, particularly when they have a history of breaking the law."

On May 31, 2009, Viestra received a telephone call from a neighbor complaining that waste from his dairy farm was being discharged in Low Line Canal. On the same day, Viestra received a telephone call from the Twin Falls Canal Company complaining of dairy waste being discharged from his farm.

The following day, June 1, 2009, an Idaho Department of Agriculture inspector, responding to a complaint from the Twin Falls Canal Company, investigated the discharge of animal waste into the Low Line Canal. The inspector tracked the waste upstream to Vierstra Dairy where it was determined that the source of the animal waste was an open pipe on the Dairy's property.

Vierstra contended at trial that an unknown third party had taken the cap off the end of a facility pipe which resulted in the unpermitted discharge. Vierstra said he responded to the discharge on June 1 by instructing an employee to go find the pipe and put a cap on it. However, as previously noted, Vierstra had been notified twice the day before.

According to the Idaho Department of Agriculture and the EPA-Idaho Operations Office, Vierstra Dairy has a history of non-compliance relating to waste discharge violations. Some of these violations at Vierstra Dairy have resulted in administrative penalties, including fines.

On October 13, 2010, a superseding information was filed charging Vierstra with three negligent misdemeanor CWA violations under 33 U.S.C. § 1319 (c)(1)(A). The superseding information alleged that on or about March 25, June 1, and November 4, 2009, Vierstra negligently discharged process wastewater from a CAFO into Low Line Canal. The jury found Vierstra guilty for the June 1 discharge. He was acquitted by the jury on the two remaining counts.

“Protection of our waterways from contaminants and pollutants is an essential function of the federal government,” said Olson. “This prosecution serves to remind dairy operators that they must be vigilant in protecting these waterways as well.”

The case was investigated by EPA's Criminal Investigation Division.