First Phase of SWIGG Groundwater Study is Complete
Wisconsin Ag Connection - 06/07/2019
An in-depth groundwater quality study in Grant, Iowa and Lafayette Counties found that nearly a third of over 500 randomly-selected private wells did not meet health standards for total coliform, E. coli, or nitrate. The Southwest Wisconsin Groundwater and
Geology Study further concluded that 16 percent of the samples taken in April were positive for total coliform and two percent were positive for E. coli.
Project coordinators say the samples came from different wells that were tested in similar testing conducted last November, where 34 percent of those wells were positive for contaminates.
"Finding fewer coliform detections in wells tested in the early spring is consistent with what other statewide surveys have reported," said State Geologist Ken Bradbury. "This may be because bacteria die off during winter and in the winter months there are fewer
contamination sources on the land surface."
The study has provided the most robust assessment of groundwater quality in the three-county region to date.
Meanwhile, the next phase of the project will include additional biological testing of selected wells to distinguish human versus livestock microorganisms in well water. The research team will also carry out geologic studies and analyze well construction practices in
the three-county region, with the goal of determining correlations between water quality, geology and well construction.