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Information about karst

What is karst?

“Karst” is the term used by geologists to describe areas where the bedrock, usually limestone or dolomite, has been (or has the potential to be) easily dissolved by surface water or groundwater. Karst landscapes may have deep bedrock fractures, caves, disappearing streams, springs, or sinkholes. These features can be isolated or occur in clusters, and may be open, covered, buried, or partially filled with soil, field stones, vegetation, water or other miscellaneous debris.

Farmer standing next to gaping, tractor-sized sinkhole that opened up in field

A large sinkhole in Eagle, Wisconsin.
Visit our photo gallery to see different types of karst features and their descriptions.

Why is karst identification important?

Karst features can act as direct conduits for pollutants to enter groundwater, wells, springs, and streams; some endangered species live exclusively in karst features or landscapes; bedrock in these landscapes, especially around sinkholes, may be weak and prone to collapse, raising safety and liability issues.

Where can karst be found in Wisconsin?

map of Wisconsin showing location of karstMuch of Wisconsin´s karst is masked by thick layers of glacial deposits, particularly in the south-central and southeastern parts of the state. Bedrock areas in Wisconsin that have visible karst features include the Silurian dolomite in the eastern part of the state and the Sinnipee and Prairie du Chien dolomite located in the southern, eastern, and western parts of the state. Wisconsin counties that may contain noticeable karst features include Brown, Buffalo, Crawford, Dane, Dodge, Door, Grant, Green, Iowa, Jefferson, Kewaunee, La Crosse, Lafayette, Monroe, Pepin, Pierce, Richland, Saint Croix, Sauk, Trempealeau, Vernon, and Waukesha. (Enlarge map.)

Learn more about karst and shallow carbonate bedrock in Wisconsin.

Help us inventory and map Wisconsin’s karst features!

We are asking for your help. If you know of existing karst features, or encounter them during future field work, we would appreciate your completing the Karst Reporting Form. The goals of this data-collection initiative are to protect Wisconsin’s groundwater resources and endangered species, provide useful information for various land-use planning activities, and facilitate construction, agriculture, and resource planning and management activities. Information from the completed forms will be maintained at the Wisconsin Geological and Natural History Survey and is open to the public.

If you have any questions about the karst form or Wisconsin’s karst features, please contact the WGNHS at 608/262.1705. Thank you for your time and consideration!

Links to more information about karst