Karst Hazard Overview

What is Karst?

Many geologic, topographic, and climatologic factors influence the development of karst, and not all karst features—such as sinkholes, caves, and springs—are present to the same extent or develop in the same way in every karst area.

Comparing karst characteristics in the various states can be useful and informative, karst features are also locally to regionally unique, so that karst features in one state may not be completely analogous to those in another.

Where Is Karst Located in Kentucky?

Kentucky is one of the most famous karst areas in the world. Much of the state’s beautiful scenery, particularly the horse farms of the Inner Bluegrass, is the result of development of karst landscape.

The karst topography of Kentucky is mostly on limestone, but also some dolostone. The areas where those rocks are near the surface closely approximate where karst topography will form. In humid climates such as Kentucky’s you should assume that all limestone has karst development, although that development may not be visible at the surface.

The outcrop area of the limestone bedrock in Kentucky has been used to estimate the percentage of karst terrain or topography in the state. About 55 percent of Kentucky is underlain by rocks that could develop karst terrain, given enough time. About 38 percent of the state has at least some karst development recognizable on topographic maps, and 25 percent of the state is known to have well-developed karst features.

Some of the larger Kentucky cities and towns located on karst are Frankfort, Louisville, Lexington, Lawrenceburg, Georgetown, Winchester, Paris, Versailles, and Nicholasville (all located in the Inner Bluegrass Region); Fort Knox, Bowling Green, Elizabethtown, Munfordville, Russellville, Hopkinsville, and Princeton (in the Western Pennyroyal Region); and Somerset, Monticello, and Mount Vernon (in the Eastern Pennyroyal Region).

Karst Facts

Mammoth Cave is the longest surveyed cave in the world, with more than 400 miles of passages.

Two other caves extend more than 30 miles, and seven mapped Kentucky caves are among the 50 longest in the United States

Much of Kentucky‘s prime farmland is underlain by karst, as is a substantial amount of the Daniel Boone National Forest,

About 40 percent of groundwater used for drinking water in the U.S. comes from karst aquifers.

According to the Kentucky Division of Water, springs and wells in karst areas supply water to tens of thousands of private homes, and are also used by five public water suppliers serving:

  • Hardin County Water District No. 1
  • Hardin County Water District No. 2
  • Georgetown Municipal
  • Cadiz Municipal
  • Green River Valley Water District

Karst hazards that could have an impact on Kentucky’s citizens and infrastructure include sinkholes, flooding, and groundwater and surface-water contamination. Sinkholes are by far the largest and most frequently encountered karst hazards.

Karst Resources/Links

“Protecting Kentucky’s Karst Aquifers from Nonpoint-Source Pollution,” 

KGS Map and Chart 27 (series 12), Link to Printable PDF Poster

State Hazard Mitigation Plan – Karst and Sinkhole Risk Assessment

Link to the State hazard Mitigation Plan – Karst and Sinkhole Risk Assessment for more information and maps.

Have questions, contact us at help@kymitigation.org.

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