Northeast Wisconsin's Kewaunee County is home to 16 large dairy operations. On those CAFOs, or concentrated animal feeding operations, are tens of thousands of cows, who produce lots of manure. Neighbors have become increasingly worried that, that manure is contaminating nearby wells.
Though the county hugs Lake Michigan, it’s what is underground that makes the area particularly vulnerable to manure ending up where you don't want it – in the water people drink.
According to USDA microbiologist Mark Borchardt, that's because the bedrock is fractured karst and the soil "can be so darn shallow."
"There are portions I have walked with county residents and you can scrape your foot and you can scrape the soil and be at bedrock right away,” he says. This allows manure to easily slip through those cracks and quickly infiltrates the groundwater.
Borchardt says when he read about concerns in Kewaunee County, he decided to check it out. “I took some early sample in May of 2014, it was that long ago, sampled 10 homes….these were people that had problems with their water. I saw the data, couldn’t believe the level of contamination of the things we found,” he says.
Borchardt found fecal contamination in seven of the 10 wells. “And that’s when we decided to pursue this research,” he says
In April 2016, Borchardt along with scientists from UW-Oshkosh and the US Geological Survey randomly selected and tested more than 100 households.
They were wading into contentious waters by setting out to pinpoint the fecal contaminant. “People living out in the country were blaming the dairy producers and the dairy producers were blaming the septic systems of the people living in country homes in the surrounding countryside,” he says.
Borchardt uncovered evidence of both. “Of the 131 wells that we samples, we had 40 wells with bovine manure in them and we had 29 wells with evidence of human waste water,” he says.
Seven wells contained both varieties.
Borchardt and his colleagues sampled during each season of the year. They found more contamination from cattle during wet weather. When farmers spread manure in fields and heavy rain follows, the mixture percolates more readily into the groundwater.
Scientists can amass more useful information, if they test more private wells in Kewaunee County, he says. There are over 4,900.
"The last thing we would like to do with all this data is to be able to build a statistical model that identifies the risk factors for contamination," Borchardt . "We take a hydrogeologic perspective, look at things like well construction variables, weather variables – like rainfall and snow melt – and land use variables, say proximity of a manured field to a well, so we can identify which of those is most important."
Borchardt presented his findings at the Kewaunee County fairgrounds Wednesday evening. Approximately 200 residents attended.
MORE ON WEDNESDAY's MEETING: Fecal Microbes Found in 60 Percent of Sampled Wells in Kewaunee County
And while Borchardt continues to look to science for insight, some residents say what is overdue is political leadership and funding. Back in 2014 they called on the EPA to intervene.
Governor Walker sees, as part of the solution, a massive digester. The system would process manure from multiple Kewaunee County dairies and use it to create energy.
The Public Service Commission is accepting applications for the project until July 3 and released this video to explain "about manure digesters and why they're good for Wisconsin."