Frequently Asked Questions About Karst
The word "karst" is the term used by geologists for areas with sinkholes, caves, and springs. It describes the land surface as a whole, not a single feature.
Karst underlies about half of the state. See Where Is Karst Located in Kentucky?
The three most common hazards are flooding, cover collapse, and groundwater contamination. Exposure to radon is also a risk. Read more about karst hazards.
Caves are surveyed (mapped) by cavers, who generally use a handheld compass and tape measure to determine the length and direction of cave passages. The size of a cave depends on what you're measuring. The largest single chambers in Kentucky are in caves in Edmonson County and Wayne County. The deepest single pitches (or vertical drops) are in Barren and Wayne Counties. The caves with the greatest overall range in elevation are in Edmonson, Wayne, and Letcher Counties. The cave with the longest cumulative length is Mammoth Cave, which underlies parts of Edmonson, Barren, and Hart Counties. The current surveyed length of Mammoth Cave is about 425 miles. Other long caves are in Pulaski and Hart Counties. For more information, see Currens, J.C., 1992, Caves, in Kleber, J.E., ed., The Kentucky encyclopedia: Lexington, University of Kentucky Press, p. 75–78.
If you have a closed depression that was not excavated and the site is underlain by limestone, you almost certainly are dealing with a sinkhole. Sinkholes can be very small to large enough to cover an area of hundreds to thousands of acres.
A cover-collapse sinkhole is formed by sudden collapse of the soil into the underlying karst cavities. If you know about a cover-collapse sinkhole, please report it.
The safest strategy, both from an engineering and environmental viewpoint, is not to fill a sinkhole. If the sinkhole is a hazard to livestock, put a fence around it. If filling the sinkhole is essential to your project, or the sinkhole is a danger to people, there is a right way to do it.
Building inside a karst sinkhole is never a recommended practice. Check topographic maps and maps of floodprone areas, and ask local residents if the area has ever flooded.
Precipitation recharges a karst aquifer rapidly and without filtration, because the soil macropores and karst conduits are too large to mechanically filter the water, and flow is too fast for pollution to be adsorbed on the soil and rock of the aquifer.
A formation, a group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs. Read more about aquifers.
Groundwater flows in karst aquifers in conduits and caves that were formed by groundwater enlarging fractures. Flow is faster than in granular aquifers, it is turbulent, and conduits can cross beneath surface watershed boundaries.
Yes, but it will cost more than building on nonkarst terrain. We recommend that extra precaution be taken to avoid structural problems in the future.
Contact the "Kentucky Speleological Survey"
To get the most out of caving, in a safe way, get involved with a local chapter, or grotto, of the National Speleological Society.
To get the most out of caving, it's a good idea to get involved with a local chapter, or grotto, of the National Speleological Society. The members know where caves are and how to safely explore them.