Certain parts of south-central Indiana that are extensively underlain by limestone
and that possess special hydrologic conditions are referred to as "karst
areas." Wells and springs in karst areas may provide large quantities of
water, but it is highly susceptible to contamination and is often unsafe for
human consumption because surface runoff is generally not filtered by soil or
bedrock in these areas.
The Indiana Natural Resources Commission provides
information on rules and policies governing certain activities in karst areas.
For an overview
of karst geology and hydrology, visit Karst
in Indiana by the Indiana Geological Survey.
An investigation by the IGS of contamination in Spring Mill State Park, located
in the karst area, is titled Potential Nonpoint-Source
Contamination of the Spring Mill Lake Drainage Basin.