The Iowa Department of Natural Resources says the map is available to help Iowans find out about what's in the earth below towns and farms. It was produced by the state's Geological and Water ...

This map shows the areas of northeast Iowa where Karst bedrock is likely to occur. Shallow wells located in areas of Karst bedrock can have poor water quality.

Their map showed strong agreement with existing Quaternary geologic maps while adding a user-controlled level of scale. The results are published in the Winter 2008 issue of Soil Survey Horizons.