Manure tanker in field

The state is proposing new restrictions on spreading liquid manure on fields in parts of the state with vulnerable drinking water supplies. 

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After more than a decade of citizen complaints about unsafe drinking water and years of pressure from the federal government, Wisconsin may tighten controls on dairy manure disposal in places where water is most susceptible to health-threatening contamination.

The state hasn’t previously created different standards for farmers in different parts of the state. The move was forced by ineffectiveness of existing statewide rules to remedy hazardous drinking.

The state Department of Natural Resources is holding hearings this week on proposed limits for liquid manure farmers can deposit on fields in 15 counties where disease pathogens drain quickly into the aquifer through thin layers of topsoil and fractured bedrock.

“This is the first time the state has recognized one size doesn’t fit all in the diverse land use and geology that we have here,” said Jim VandenBrook, director of Wisconsin Land and Water, which represents county soil and water conservation personnel. “That’s a big deal.”

Conservation groups said the DNR’s draft rules are a good first step made up of compromises reached after two years of talk, but scientific evidence shows more of the state’s drinking water needs protection and standards should be even more stringent.

Breadth of effort at issue

In contrast, a Wisconsin Dairy Business Association lobbyist said the proposal was “fairly well suited” to address some problems, but the association opposes the regulation’s breadth, questioned whether limits were too strict, and maintained that smaller farms should be forced to comply just like large ones.

“This is tied to a goal other than growing crops well, which is fine, but we want to find a way to be protective of water and grow crops well,” said association lobbyist John Holevoet. “We want those numbers to be checked and agronomically sound.”

The association is made up of large and small farms, but its board is dominated by large feedlot operators who must comply with rules, Holevoet said.

State law doesn’t require compliance by small farms unless they accept government grants that are in short supply.

VandenBrook, whose association is made up of county employees who work with farmers on environmental protection, said the proposal could clean up drinking water, but government and industry groups must work to ensure broad participation — including voluntary compliance by many small farms.

VandenBrook estimated that the rule change would be enforceable for about 40 percent to 50 percent of acreage in areas it covers. Farm associations should push members to follow the rules, he said.

“You only need a few holes in the network and you can contaminate wells,” VandenBrook said. “This ongoing set of water crises in the northeast part of the state isn’t good for the agriculture industry and isn’t good for dairy.”

More than 30 percent of wells tested in Kewaunee County, which has a high concentration of large dairy feedlots, have been tainted with bacteria from livestock. Recent random testing has found higher rates of contamination.

But there is a larger area with similarly vulnerable groundwater, including counties in the southern part of the state that the DNR doesn’t propose to cover with the new rules, said Sarah Geers, an attorney for Midwest Environmental Advocates.

Areas ‘still vulnerable’

Contaminants can cause serious illnesses, but outside Kewaunee County awareness of the problem isn’t high, and residents who suffer flu-like symptoms may not realize they could be coming from tainted well water, Geers said.

“Other parts of the state are still vulnerable to groundwater contamination,” said Scott Laeser of Clean Wisconsin, which joined Midwest Environmental Advocates in petitioning the U.S. Environmental Protection Agency to intercede in Wisconsin.

State geologist Ken Bradbury said the fractured bedrock in the southwestern part of the state is often covered by more topsoil that sometimes includes clay, which can help slow the downward flow of pollutants.

The region’s hilly terrain and deep aquifer make it more difficult and expensive to monitor, Bradbury said.

“We believe that (southwestern Wisconsin) is a vulnerable area, but there just hasn’t been as much research or monitoring done in the southwest as in the northeast,” Bradbury said. “I think that is why the new regulations are focused on the northeast.”

Rules currently forbid large animal feedlots statewide from spreading liquid manure where there is less than 2 feet of topsoil.

Topsoil seen as key factor

The proposed changes would add limits for places with up to 20 feet of topsoil in Brown, Calumet, Dodge, Door, Fond du Lac, Kenosha, Kewaunee, Manitowoc, Milwaukee, Outagamie, Ozaukee, Racine, Walworth, Washington and Waukesha counties, based on soil type and depth to bedrock.

The dairy association accepts the proposed restrictions on topsoil that is 5 feet thick or less, but opposes limits for topsoil between 5 feet and 20 feet thick, because mapping of those areas is insufficient, Holevoet said.

Maureen Muldoon, a UW-Oshkosh geologist who was involved in studies that form the proposal’s foundation, said restrictions in the 5- to 20-foot zone simply call on farmers to be careful. Water-carrying pollutants pass through 18 feet of topsoil in 24 hours in places like Kewaunee County, Muldoon said.

The DNR and a task force that studied northeastern Wisconsin rated the vulnerability of groundwater below fractured bedrock as “extreme” with 5 feet or less of topsoil, “high” with 5 feet to 15 feet, and “significant” with 15 to 50 feet.

Risk is increased by features like sinkholes that create faster conduits, and risk can be lessened by substantial layers of clay-like soil.

The proposed rules spell out other restrictions on manure-spreading — based on such factors as rain, frozen ground and proximity of wells — that already apply to large feedlots, and make them applicable to smaller farms.

Meetings scheduled

in Green Bay, Madison

The DNR will provide information and listen to comments in meetings starting at noon Friday in Green Bay and in Madison. Written comments will be accepted through Oct. 4.

After that, the Natural Resources Board, Gov. Scott Walker, and members of the Legislature will be asked to approve the rules, which could take effect next summer.