PLATTEVILLE, Wis. – The Professional Dairy Producers of Wisconsin held a Water Matters farm tour field day June 25, visiting two farms in southwest Wisconsin to learn about what dairy farmers are doing to protect and improve water quality.
    “In perspective, in America, while our waters are not perfect, we have done a good job of soil conservation and practices, but there is always room to be better,” said Shelly Mayer, PDPW executive director, of the importance of dairy farmers taking the initiative to improve groundwater quality. “Recognizing that water is life and water is food, that this is such a critical conversation.”
    Banner Ridge Farms and Kieler Farms, both of Platteville, Wis., hosted the event.
    In addition to tours, participants heard from Dr. Mark Borchardt from the Laboratory of Infectious Disease and the Environment at the United States Department of Agriculture Agricultural Research Service’s Upper Midwest Water Science Center in Marshfield, Wis.
    “Some of the things I’m going to say today, you’re not going to be happy to hear,” Borchardt said. “Keep in mind, I don’t have an agenda. I’m not anti-ag, I’m not anti-septic system. I’m a scientist, and my job is to take questions and issues people have, turn those into effective study designs, generate data and then publish papers.”
    Borchardt spoke of what he calls the tragedy of an open access resource: private household wells.
    “A private well is a unique thing,” Borchardt said. “If you own a well, you paid to have it installed, you pay to maintain it, you pay property taxes on the value of that well, but you don’t control the water coming into it.”
    Borchardt said groundwater aquifers that feed household wells are not privy to property lines and are a shared resource, a point that has caused a great deal of turmoil in Wisconsin’s Kewaunee County.
    Borchardt said Kewaunee County has faced two growing and competing sections of land use recently: a growing number of dairy cows and an increased residential growth due to urban sprawl from the Green Bay, Wis., area.
    “When I started off with this study, I dealt with homeowners on one side of the room pointing at the dairy industry on the other side of the room, accusing them of contaminating their wells,” Borchardt said. “The dairy industry pointed their fingers back saying, ‘No, it’s the septic systems that are polluting the wells.’”
    According to Borchardt, both groups contribute to a fecal waste problem.
    “You’ve got more cows producing fecal waste, and you have more humans producing fecal waste,” Borchardt said. “That’s the issue in this county. Like other rural areas, Kewaunee County disposes of fecal wastes on the landscape through various methods of manure application and the 12,000 septic systems in Kewaunee County.”
    According to Borchardt, the reason this is an issue is because the fractured dolomite bedrock aquifer formed during the Silurian time period, that lies along the east coast of Wisconsin and supplies the groundwater to Kewaunee County, is vulnerable to contamination due to the vertical and horizontal fractures found in the bedrock that can be more than 1 mile in length.
    “When it rains in Kewaunee County in northeast Wisconsin, that water reaches groundwater very, very quickly,” Borchardt said. “As that rain moves, it carries any surface contaminants to the groundwater.”
     Borchardt is leading a study to look at groundwater quality in Grant, Lafayette and Iowa counties based on that region having a similar type of fractured bedrock.
    Borchardt’s research objectives were looking for an estimate of the county-wide contamination rate for nitrates and indicator bacteria in relation to bedrock depth. A second objective was to determine the source of the fecal contamination. A third was to identify contamination risk factors for private wells.
    Nearly 5,000 private wells in Kewaunee County were selected for random sampling, selecting wells from three bedrock depths. Of the selected wells, 50% participated in the study, and samples were taken twice, once in November 2015 and once in July 2016.
    Researchers learned that the deeper the depth of soil was to the bedrock, the more pollution protection was afforded to the groundwater.
    “Depth of bedrock really matters,” Borchardt said. “At zero depth to bedrock there is a 35% chance of a well testing positive for chloroform bacteria and a 24% chance of having a nitrate level over the health standards of 10 parts per million. Believe it or not, there are places in Kewaunee County where you can scratch your foot, and you are on bedrock. It’s zero depth to bedrock.”
    Data collected to date in the Southwest Wisconsin Groundwater and Geology study focusing on the southwestern area of Wisconsin has found that the percentages of wells with water quality issues in Grant, Lafayette and Iowa counties generally exceed the state-wide averages.
    The SWIGG study used microbe identification to learn where the source of contamination was coming from. A total of 33 wells from 131 sampled contained any human microbe. Human bacteroides were found in 27 of those 33 wells. In terms of pathogenic microbes, rotavirus A was found in seven of the wells, while Cryptosporidium hominis and adenovirus A were each found in one well.
    Bovine-specific microbes were found in 44 of the 131 sampled wells. Ruminant bacteroides were found in 36 of those 44. Pathogenic microbes were found in 21 of the wells, including 12 with rotavirus A, eight with Bovine polyomavirus and one with Bovine enterovirus.
    Other fecal microbes from non-specific hosts were present in 79 of the 131 wells tested, including 13 wells that contained Cryptosporidium parvum. Non-pathogenic pepper milk mottle virus also appeared in 13 of the wells.
    According to Borchardt, the importance of identifying the contamination risk factors lies in being able to understand what the causes of the contamination might be and how a change in the magnitude of the risk factor affects the magnitude of the contamination. This information can provide those in charge of making policy and creating laws options for preventing contamination, such as appropriate setbacks, the allowable density of potential contamination sources, vulnerable time periods in relation to weather events, and best practices for well constructions.