The Minnesota Department of Natural Resources has published the Clay County Geologic Atlas-Part B. Part B covers groundwater conditions and sensitivity to pollution. It expands on Part A, the geology atlas previously published by the Minnesota Geological Survey.
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.
Clay County straddles a major ice age boundary, resulting in some of the most variable geologic conditions in the state. The eastern portion of the county has coarse-grained glacial deposits with moderate to very high pollution sensitivity. The western portion is dominated by clayey glacial lake sediment with a total thickness of up to 140 feet, which protects the aquifers beneath, giving them ultra-low pollution sensitivity. The water has been in some of these aquifers for more than 35,000 years.
The atlas is available online and in printed form:
- Online: PDFs of the report and maps, GIS files and program information are available by searching “DNR, Clay County Geologic Atlas, Part B.” The GIS folder includes GIS files and associated metadata for the water table, wells, and maps for groundwater flow and pollution sensitivity. The ArcMap file displays the data as shown on the published maps and includes hyperlinks to image files of the published cross sections.
- Paper copies: Part A and B atlases can be purchased from Minnesota Geological Survey Map Sales, 612-626-2969. Prices for each atlas package range from $12–$15.
Partial funding for this project was provided by the Clean Water Fund and the Minnesota Environment and Natural Resources Trust Fund.
For more information on other counties and studies, see the County Geologic Atlas website at mndnr.gov/groundwatermapping.