ABSTRACT
Olmsted County, the most populous county in southeastern Minnesota had an opportunity to test its ability to use geological information to protect groundwater when a new landfill site was required. Parts of southeastern Minnesota have spectacular karst geology. Geologists from the University of Minnesota and the Department of Natural Resources have studied the development of karst in the area, mapped the distribution of karst features on the surface, and begun to understand the patterns of subsurface water flow. Southeastern Minnesota's sinkholes form when water moving through the fissures removes the overlying soil and causes the ground surface to sag. The dangers of water contamination in southeastern Minnesota first received widespread attention in 1939 when eleven cases of typhoid fever and one death were attributed to drinking from a contaminated water supply. Water flowing from the melting glaciers drained through southeastern Minnesota, removing sediment and eroding the deep river valleys that characterize the area's topography.
