Glacial geology mapping in Berrien County, Michigan: Resolving the third dimension for increasing the accuracy of resource assessment

In Michigan, 92% of the state's glacial geology remains unmapped at a scale useful for resource planning, which we consider a scale of at least 1:50,000. Virtually every hydrogeologic report, environmental assessment, and remedial investigation contains a section on the geologic setting of the site being studied. For most of Michigan, this means the glacial geology of the site. The only map available for the entire state is the “Quaternary Geology of Michigan”, published by the Geological Survey Division in 1982. This map, at a scale of 1:500,000, was never meant to be used for detailed investigations. In the absence of anything better, it is commonly used as a guide to the stratigraphy that can be expected for site investigations. At scales typically around 1:1,200, these sites are barely a pinprick on the state map. It should come as no surprise when the state map doesn’t correlate well with the site map. Michigan has a reputation for plentiful water resources. According to the National Ground Water Association, Michigan has more water wells that any other state (about 1.2 million). About half of these wells are in glacial aquifers, and the majority of bedrock aquifers are recharged though glacial materials. Yet, these deposits have not been adequately mapped at a scale that enables planners to predict where the water-bearing formations exist, let alone estimate their potential for water production. Without this information it is not possible to determine safe yields for these formations or to delineate sole-source aquifers, let alone perform the source-water assessments currently required by the EPA.