Mapping Bedrock: Tools to Identify Loss Potential in Vulnerable Landscapes
In the summer of 2008, UW Discovery Farms partnered with the Wisconsin Geological and Natural History Survey (WGNHS) and the Calumet County Land and Water Conservation Department to study the thickness and texture of the materials between the bedrock and land surface.
The objective of the study was to map the depth-to-bedrock in Calumet County, an area that has long been grappling with groundwater quality issues from nonpoint source pollution. In landscapes such as those found in Calumet County, carbonate bedrock formations are extensively fractured. As a result, there is very little surface runoff in places where fractured bedrock is close to the land surface. Water quickly and easily infiltrates to the subsurface.
Researchers found that groundwater in Calumet County aquifers used for drinking-water supplies has a moderate to high risk of contamination. This susceptibility to contamination varies across the county and is largely dependent upon the thicknesses of the unlithified materials over the groundwater aquifers.