In a lawsuit filed last month by the Wisconsin Dairy Business Association, the group argues the Wisconsin Department of Natural Resources (DNR) has long overstepped its authority in regulating large animal farms.

A court win could widely impact the state’s ability to oversee manure storage and disposal practices unless state agents can show a farm had contaminated wells and surface waters.

Large livestock farms, or CAFOs, have fallen under recent scrutiny following large manure spills with environmentalists calling for increased oversight and regulation.

Earlier this year, Emerald Sky Dairy in St. Croix County came under fire when a large-scale manure spill led to a DNR investigation after going unreported for nearly four months.

Removing DNR regulations would task counties with the responsibility, but some county officials worry because they have thinner staffs than the DNR and little ability to regulate beyond county lines.

The DNR lists more than 250 CAFOs across the state, up from fewer than 50 in the mid-’90s. The vast majority of those farms are dairy operations, and the DNR classifies CAFOs as farms with more than a thousand animals.

State auditors found shortfalls in the department’s practices for policing pollution last year. Citing staff shortages, the report detailed infrequent farm monitoring and permit backlogs.

St. Croix County Planning and Conservation Specialist Tamara Witmer said the county only has one staff member responsible for fielding calls about a manure spill to one of its six CAFO farms.

“If the DNR is too over-regulating, then (farmers) can put a shovel in the ground and put a manure storage wherever they want?” she said. “We don’t even let a developer put a shovel in the ground without hiring an engineer.”