The Minnesota Department of Natural Resources will collect groundwater samples from about 90 wells in Cass County this summer for use in the Cass County Geologic Atlas, Part B.
The DNR will contact select owners by mail or phone for permission to sample their wells. Sampling involves measuring the depth to water and collecting a water sample for laboratory analysis. Participation is voluntary and owners will receive a report of the laboratory results.
Wells are selected based on geology, location, well depth and well construction. Participation helps create county maps and descriptions of groundwater distribution, movement, conditions, and the pollution sensitivity of aquifers. The final products will be available as printed maps, reports, and geographic information system (GIS) files on the web.
The atlas can be used to help identify viable water sources, evaluate supply, identify recharge sources and flow, manage sustainability, guide decisions for well and septic system construction, assist in well head protection for public water supply, and assess pollution sensitivity.
County Geologic atlases are produced in two parts over the course of several years. Part A covers the geology of a county, and was completed for Cass in 2018 by the Minnesota Geological Survey. Part B will expand on this information to cover the hydrogeology (groundwater) using the new well-sampling data. The DNR expects completion in 2020.
The DNR County Geologic Atlas program is funded in part by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources. Funding also comes from the Clean Water Fund, which receives 33 percent of the sales tax revenue from the Clean Water, Land and Legacy Amendment approved by voters in November 2008.
A full description of this DNR program and status reports for atlas products is available at mndnr.gov/groundwatermapping.