IDENTIFYING AND MAPPING KARST IN THE HIAWATHA NATIONAL FOREST, UPPER PENINSULA OF MICHIGAN

The Hiawatha National Forest (HNF) is about 1.0 million acres located in the Upper Peninsula of Michigan. The forest geomorphology is characterized by glacial deposits from the last Ice Age about 11,000 to 9,000 years ago. The retreat of miles-thick continental ice sheets created glacial lakes and are associated to the deposited unconsolidated boulders and sediment. Sedimentary bedrock consisting of primarily dolomite and sandstone are common sources for ground water in the HNF.

This project expands on previous karst identification and mapping for the HNF. Research is in collaboration with the Geological Society of America GeoCorps America program and the HNF. Areas of interest were identified using LiDAR (Light Detection and Ranging) and 1-foot resolution satellite imagery. The LiDAR data was analyzed for key features resembling sinkholes, outcrops, boulders, ledges, sinking streams, and caves. Information on depth to bedrock was also analyzed to determine zones of industrial hazards for development. Potential karst features from LiDAR analysis were field verified for map accuracy.

Karst mapping is important for conservation of groundwater aquifers, unique flora and fauna ecosystems, and heritage sites. It is also necessary for machine operability and for regular forest operations that pose risks for groundwater contamination and soil disturbance. Heavy machinery fluids could leach into soils and travel through groundwater conduits into the water table. Areas of shallow soil coverage overtop carbonate bedrock are also sensitive to heavy equipment operations due to the direct compaction.