Count of unsafe wells in Kewaunee County rises
More wells are contaminated with coliform, nitrates or E.coli in Kewaunee County than previous studies showed, according to the results of a new scientific study of the county’s wells.
Of 320 wells tested in November, 110 wells or 34 percent were found to be unsafe, Davinia Bonness, Kewaunee County conservationist reported at a meeting of the county’s Land and Water Committee Tuesday.
Of the 320 wells sampled, 86 or 27 percent were found unsafe due to the presence of total coliform, five wells or 2 percent had E. coli, and 37 or 12 percent had nitrate levels higher than 10 mg/l, the state maximum, Bonness said. Some wells had more than one of these contaminants, she said.
The study should end years of disagreement among government officials, farmers and environmentalists over the extent of the well contamination problem in Kewaunee County. Previous voluntary testing programs over 11 years reported that the number of contaminated wells in the county was approximately 29 percent. But some officials argued that the number was not based on a scientific sampling and that the number was not actually that high because people who lived in areas with karst bedrock, which made their well more vulnerable to contamination, were more likely to participate in the program.
The new scientific test, which was primarily funded by a grant from the Department of Natural Resources, used a stratified random sampling to provide a more precise estimate of the countywide well contamination rate and to ensure that wells with different depths to bedrock were equally represented, Bonness said. She said that the wells to be tested were randomly selected by computer.
Property owners with contaminated wells have already been notified so that they can take appropriate remedial action, Bonness said.
Testing of the samples was conducted by the staff of the Environmental Research and Innovation Center at University of Wisconsin-Oshkosh.
Of those wells with coliform contamination, 20 will be chosen for testing to determine whether the contamination is from bovine or human viruses, Bonness said. In addition, a second sampling of wells will be conducted in the spring.
While most environmentalists and residents blame excessive spreading of cow manure for the well contamination problem in the county, others contend that the contamination is coming from septic systems and other pollutants.
More than 80 percent of voters in the county last April voted to implement a groundwater protection ordinance preventing the mechanical application of waste (typically manure) to land having 20 feet or less in soil depth to bedrock during the time period of Jan. 1 to April 15.
“The results support the whole idea that we are trying to find solutions to this problem,” said Ron Heuer, county chairman. “Ultimately, the solution is to find ways to treat cow manure and get it off the fields.”
In addition, the UW-Oshkosh team is compiling information to provide results based on different depth-to-bedrock stratifications: 0-5 feet, 5-20 feet, and greater than 20 feet. The results of the stratification analysis of the wells will be available in January, Bonness said.
“I don’t have an opinion on the results until we get the rest of the information on the depth of the wells so we can develop a plan to improve the situation,” said John Pagel, Land and Water Committee chairman.
In addition to UW-Oshkosh, the county is working with investigators from the U.S. Geological Survey, U.S. Department of Agriculture and UW-Stevens Point.
This article originally appeared on Green Bay Press Gazette: Count of unsafe wells in Kewaunee County rises