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Questions remain about Bradford dairy proposal

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Tony DiNicola

Bradford Township - Approximate locations of residential wells

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Rick C. Wietersen

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Todd Tuls

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Ken Bradbury

BRADFORD TOWNSHIP — State and local officials don’t think the proposed Rock Prairie Dairy would pose a greater risk of ground or surface water contamination than agricultural practices already taking place.

Nor do they think the proposed farm’s wells would reduce the drawing power of residential wells in the area.

They are not yet prepared to say, however, whether the farm would impact local residents’ health by the creation of airborne pathogens or other pollutants.

Those four topics—ground water contamination, surface water contamination, ground water use and the spread of pathogens—are the four most common concerns from opponents of the proposed 5,200-cow dairy. They have been repeated at public hearings, in letters to the editor and in phone calls or emails to the Gazette.

Weather permitting, Nebraska dairy farmer Todd Tuls could break ground the first week in April at the northeast corner of the intersection of Highway 14 and Scharine Road in far eastern Rock County.

Since August, a small army of state and county legal, environmental and public health professionals has been scrutinizing the design plans for the proposed Rock Prairie Dairy.

Pages of plans show how the 5,200-cow farm is designed to have a minimal impact on groundwater, surface water and air quality, said Tom Sweeny, county conservationist with the Rock County Land Conservation Department. The farm would have tools to monitor much of its activities.

But plans are only plans, said Wisconsin hydrogeologist Ken Bradbury. In real life, equipment breaks and regulatory agencies fail to communicate.

Stuff happens, Bradbury said.

“The larger these things get, the consequences of a spill or some kind of failure become more serious,” said Bradbury, who works for the Wisconsin Geological and Natural History Survey, a part of the UW-Extension.

Tuls has said that Wisconsin’s DNR regulations are stricter than those of the Nebraska Department of Environmental Quality. In Wisconsin, he is required to show “each junction and each pipe,” Tuls has said.

The Wisconsin Health Department reviewed the plans, and the Rock County Health Department continues to do so, Environmental Health Director Tim Banwell said.

While the plans have been carefully read, some information simply won’t be available until the farm is operating, said Rick Wietersen, a groundwater program specialist with the county health department.

“There are a lot of things out there that come into play,” Wietersen said. “We don’t know all the answers.”

Nutrient management

One thing would change very little if Rock Prairie Dairy gets up and running: the amount of nitrogen applied to farm fields in the area, said Brian Mooney, an agronomist with the DeLong Co. of Clinton.

In addition, the type of crops grown to meet the dairy’s needs could minimize erosion, Mooney said. Mooney created Tuls’ nutrient-management plan, a state-mandated document that spells out how and when fertilizer would be applied to each field.

Nitrogen is one of the elements that poses a risk to groundwater contamination. Soil erosion poses a risk to surface waters.

Tuls has contracted more than 5,000 acres for manure disposal, and all of those fields are in the plan, Mooney said.

The total amount of nitrogen spread on the fields would be about the same as it is now, Mooney said. The only difference would be that the nitrogen would be created by cattle rather than through the use of fossil fuels, he said.

A large part of Tuls’ cows’ diet would be corn silage, which is harvested in mid-summer while the stalks are green. In that case, producers would plant a cover crop to protect the soil and prevent runoff for the remainder of the growing season and into the spring, Mooney said.

Fields planted with cover crops require less nitrogen, because the cover crop can be tilled into the soil as a green fertilizer, Mooney said. Also, regulations prohibit producers spreading manure to apply as much nitrogen in the fall as producers using commercial fertilizers, Mooney said.

Many of the fields in Tuls’ nutrient-management plan are not in such plans today, Mooney said. Farmers that use such plans are required to meet state mandates for limiting soil loss and phosphorous use.

Pivotal pause

A recent change in Tuls’ manure application plan bought some time for people concerned about the spread of airborne pathogens.

Tuls on March 21 announced he would remove the center-pivot manure sprayers from his state application. The change is not permanent, but it could give Tuls and Wisconsin officials time to research how the pivots would work in Wisconsin.

Tuls would be one of the first Wisconsin producers to use irrigators to spray watered-down, untreated manure onto growing crops. Opponents of the practice say this method carries the risk of spreading manure droplets, pathogens or bacteria.

The Wisconsin Department of Natural Resources received enough concerned comments from local residents about the pathogen issue that the DNR asked the Wisconsin Department of Health Services to get involved.

A state toxicologist issued a memo with suggestions to make the sprayers safer for humans. Among other things, the memo suggests the pivots be at least 500 feet from homes, the manure be treated and handled properly and the application be designed to have minimum impacts.

The farm’s manure storage lagoons would be equipped with covers, which would greatly reduce odors and could reduce the spread of pathogens, Wietersen said.

Tuls could come back with a change to his pivot plans or the data that proves the pivots meet the intent of the health department memo, Cain said.

Liquid balance

Protecting the environment and the health of the public often is a balancing act, Wietersen said.

For example, the Rock Prairie with its high-quality soils and flat topography naturally protects surface water, Sweeney said. The soil quickly absorbs water, which reduces the risk of runoff, he said.

But because the water can move quickly through soil and gravel to bedrock below, it poses some risk to the aquifer, said city of Janesville utility director Dan Lynch.

The Rock Prairie is the recharge area for the shallow aquifer from which the city of Janesville pumps much of its water. Because the nitrate levels tend to be high in that aquifer, the city also pumps water from a deeper aquifer and mixes the water from both, Lynch said.

Water moves slowly underground, Lynch said.

“We’re dealing today with agricultural practices from 20 years ago,” he said.

The depth to water on the Rock Prairie Dairy site varies from 6 to 22 feet, according to the DNR’s draft environmental analysis of the dairy farm. According to records for residential wells in the area, the depth to limestone bedrock—which acts as a poor water filter—is between 6 and 25 feet.

Soils in the area are “generally deep and moderately- to well-drained” over layers of sand and gravel or glacial till, according to the DNR’s environmental analysis. “Till” is the mix of sand, clay and gravel left by glaciers, Bradbury said.

In general, till in Rock County has the depth and quality needed to act as a filter to keep contaminants out of bedrock. Bedrock makes a poor water filter, Lynch said.

The Rock County Health Department has water samples from 21 of the 70 residential wells within a two-mile radius of the farm, Wietersen said. Some of those tests are a few years old. Tuls conducted many of the newer tests as part of his research for the site plans, he said.

The health department recommends annual testing of private wells, but many rural property owners ignore the suggestion, Banwell said.

Among the 21 well tests on file, 38 percent exceed safe nitrate levels, according to health department data. The test results range from almost no nitrates to more than double safe levels, the data indicate.

The area near the proposed farm is not the only part of Rock County with high nitrates in drinking water.

In 2009, 32 percent of private Rock County wells tested for nitrates exceeded the allowable standard, according to health department data.

Between 1990 and 2006, the county collected 482 samples from private wells. Of those samples, 25 percent exceeded the standard for healthy nitrate levels, according to geological and natural history survey data.

Wietersen said the farm’s plan is adequate to protect groundwater.

“If any of us thought there would be a significant impact to the aquifer, there would be action to stop that,” he said.

Sheer size

The 73.7 million gallons of manure and wastewater that would be produced annually by the Rock Prairie Dairy pose the biggest long-term environmental risk to the community, the DNR’s environmental analysis states.

Nothing eliminates the possibility of a manure spill, but the farm would have a spill-discharge plan as well as an emergency management plan, Sweeney said.

Historically, off-site spills are more common that on-site spills, Sweeney said.

“The tendency is to do a good job on site,” Sweeney said. “If a spill occurs, it is usually from punctures in drag lines off site.”

Drag lines are hoses through which manure is pumped to tractors, which spread the manure onto fields. The tractors drag the hoses as they drive across the fields.

In the case of Rock Prairie Dairy, the lack of large rocks in the fields would make for safer drag-lining, Sweeney said. In addition, much of the manure would flow to fields through underground pipelines, which would be more stable than drag hoses, he said.

Then again, if an underground pipe leaked, it could be some time before the leak was detected, Wietersen said.

“There’s that balance again,” he said.

Water draw

Rock Prairie Dairy’s two proposed high-capacity wells would be drilled into a sandstone aquifer deeper than the sandstone aquifer or sand and gravel aquifer used by residential wells in the area.

The farm’s 500-foot wells would be lined to 250 feet.

In total, the farm would draw 175,000 gallons of water per day or 128 gallons per minute.

That’s not a “huge” amount, Bradbury said. While he hasn’t studied the plans in detail, Bradbury said the well depth and rate of water consumption seems reasonable for such a project.

Although he didn’t have the data available, Bradbury didn’t think the farm’s wells would impact residential wells farther than a half-mile from the farm.

He said a simple mathematical formula can predict the cone of depression—the dip in the water table—created by any well. Bradbury suggested imagining the way a milkshake forms a cone-shaped indent when you suck on a straw.

The city of Janesville’s eight wells are too far from the proposed dairy to be impacted by the dairy wells’ draw, he said.