Edmonson County, Kentucky

Major Construction

An understanding of the geology of an area can help prevent costly construction failures. Constructing this road in Warren County with a different alignment might have prevented the damages caused by subsequent sinkhole collapse. (Photos courtesy of Richard McGehee, Groundwater Branch, Kentucky Division of Water.)

About karst

More about karst

Pond Construction

Successful pond construction must prevent water from seeping through structured soils into limestone solution channels below. A compacted clay liner, or artificial liner, may prevent pond failure. Getting the basin filled with water as soon as possible after construction prevents drying and cracking, and possible leakage, of the clayey soil liner. Ponds constructed in dry weather are more apt to leak than ponds constructed in wet weather. Illustration and discussion by Paul Howell, USDA-NRCS.

A clayey-soil pond liner is placed in loose, moist layers and compacted with a sheepsfoot roller. A geotechnical engineer or geologist should be consulted regarding the requirements of a specific site. Other leakage prevention measures include synthetic liners, bentonite, and asphaltic emulsions. The U.S. Department of Agriculture-Natural Resources Conservation Service can provide guidance on the application of these liners to new construction, and for treatment of existing leaking ponds. (photo and discussion by Paul Howell, USDA-NRCS)

Dams should be constructed of compacted clayey soils at slopes flatter than 3 units horizontal to 1 unit vertical. Ponds with dam heights exceeding 25 feet, or pond volumes exceeding 50 acre-feet, require permits. Contact the Kentucky Division of Water, 14 Reilly Rd., Frankfort, KY 40601, telephone: 502.564.3410.

Environmental Protection

 

  • Never use sinkholes as dumps. All waste, but especially pesticides, paints, household chemicals, automobile batteries, and used motor oil should be taken to an appropriate recycling center or landfill.
  • Make sure runoff form parking lots, streets, and other urban areas is routed through a detention basin and sediment trap to filter it before it flows into a sinkhole.
  • Make sure your home septic system is working properly and that it's not discharging sewage into a crevice or hole.
  • Keep your cattle and other livestock out of sinkholes and sinking streams. There are other methods of providing water to livestock.
  • See to it that sinkholes near or in crop fields are bordered with trees, shrubs, or grass "buffer strips." This will filter runoff flowing into sinkholes and also keep tilled areas away from sinkholes.
  • Construct waste-holding lagoons in karsst areas carefully, to prevent the bottom of the lagoon fromcollapsing, which would result in a catastrophic emptying of waste into the groundwater.
  • If required, develop a ground-water protection plan (410KAR5:037) or an agricultural water-quality plan (KRS224.71) for your land use. (From Currens, 2001).

Mammoth Cave National Park, established in 1941, receives approximately 1.7 million visitors per year. The park is home to Mammoth Cave, which is the longest surveyed cave system in the world, with over 350 miles of passages. Approximately 45,713 acres of the park's 52,830 acres are located in Edmonson County.

Geologic Hazards

 

Karst sinkholes are common features in Edmonson County that develop in limestone bedrock. A sinkhole is any depression in the surface of the ground from which rainfall is drained underground. Karst sinkholes form when a fracture, or conduit, in the limestone bedrock becomes enlarged.

 

Limestone terrain can be subject to subsidence hazards, which usually can be overcome by prior planning and site evaluation. "A" shows construction above an open cavern, which later collapses. This is one of the most difficult situations to detect, and the possibility of this situation beneath a structure warrants insurance protection for homes built on karst terrain. In "B," a heavy structure presumed to lie above solid bedrock actually is partially supported on soft, residual clay soils that subside gradually, resulting in damage to the structure. This occurs where inadequate site evaluation can be traced to lack of geophysical studies and inadequate core sampling. "C" and "D" show the close relationship between hydrology and subsidence hazards in limestone terrain. In "C", the house is situated on porous fill (light shading) at a site where surface and groundwater drainage move supporting soil (darker shading) into voids in limestone (blocks) below. The natural process is then accelerated by infiltration through fill around the home. "D" shows a karst site where normal rainfall is absorbed by subsurface conduits, but water from an infrequent heavy storm cannot be carried away quickly enough to prevent flooding of lowlying areas. (Adapted from American Institute of Professional Geologists, 1993.)

Other Hazards

Faults are common geologic structures across Kentucky, and have been mapped in many of the Commonwealth's counties. The faults shown on this map are part of the Pennyrile Fault System, which is considered not to be active. However, earthquake damage in Edmonson County is still a possibility.

Soil creep, slumps, and landslides occurring along steep slopes may occur from erosion or ground motion associated with a strong earthquake.

Areas associated with alluvium are subject to liquefaction during a strong earthquake event. These areas are also subject to flooding.

Soils derived from alluvium deposits may have a moderate to high shrink swell capacity, which may affect structural foundations and roads.

Radon gas can be a local problem, although it is not widely distributed in Kentucky in amounts above the Environmental Protection Agency's maximum recommended limit of 4 picocuries per liter. Some areas of limestone on the map may contain high levels of uranium or radium, parent materials for radon gas. Several limestones in the state contain apatite, a phosphate mineral. Uranium is sometimes part of the apatite crystal structure, and when the limestone weathers away the phosphates containing uranium can become concentrated in the soil and ultimately give rise to high levels of radon. A few areas of moderately high radon concentrations have been recorded in the sinkhole plain, ranging from 4 to less than 32 picocuries per liter. Homes in these areas should be tested for radon, but the homeowner should keep in mind that the threat to health results from relatively high levels of exposure over long periods of time, and the remedy may simply be additional ventilation of the home.

RESOURCES

Groundwater

In karst areas such as southern and eastern Edmonson County, stormwater runoff can flow underground through large solution channels. This groundwater flow does not follow the topography of the surface, and water from one surface watershed may flow underground and reappear in an adjacent watershed. Knowledge of the groundwater flow, gained through dye-trace studies, is required to manage storm water and to protect water quality and drinking water sources. For more information about dye tracing in the area, see Currens and Ray (1998, 2000).

In this highly karstic, limestone rich county, most of the drilled wells in the southern half of Edmonson County are adequate for a domestic supply. Yields as high as 50 gpm have been reported from wells penetrating large solution channels with adequate wells producing as deep as 500 feet. In the uplands of the northern half of the county less than half the drilled wells yield enough water for a domestic supply. In low-lying areas of the Nolin River, Bear Creek, and Dog Creek and their main tributaries, most wells are inadequate for domestic use with the exception of a few wells that yield enough for a domestic supply from depths of 150 feet or more. Springs with flows ranging from a few gallons per minute to 50,000 gpm are found in the county. Minimum flow generally occurs in early fall, maximum flows in late winter. For more about the groundwater resources of the county, see Carey and Stickney (2001).

Surface Water

The U.S. Army Corps of Engineers constructed the Nolin River Dam in 1959 to prevent flood damage along the Nolin and Green River drainages. The 166-ft high dam created a 5,795-acre lake, which extends into Hart and Grayson Counties. Nolin Lake State Park, located just north of the dam, covers an area of 333 acres in Edmonson County. Not only is Nolin Lake a recreational area, but it's also a drinking water source for Edmonson County.

This levee was constructed to control flooding along the Big Reedy Creek drainage in Edmonson County.

Houchins Ferry (above) is one of two ferries within Mammoth Cave National Park. Both ferries transport vehicles across the Green River, which is a major drinking water source for Edmonson County.

Energy

As demonstrated in this picture, oil well "pump jacks" (foreground) and tanks (background) are a familiar site to residents in Edmonson County. Approximately 400 oil and gas wells have been completed in Edmonson County.

REFERENCES

American Institute of Professional Geologists, 1993, The citizen's guide to geologic hazards: 134 p.

Carey, Daniel I., and Stickney, John F., 2001, Ground-water resources of Edmonson County, Kentucky: Kentucky Geological Survey, Open-file Report OF 01-31, 31 p.

Currens, James C., 2001, Protecting Kentucky's Karst Aquifers from Nonpoint-Source Pollution: Kentucky Geological Survey, Map and Chart Series 27, Series XII, poster.

Mitchell, Michael J., 2001, Soil Survey of Butler and Edmonson Counties, Kentucky: U.S. Department of Agriculture, Natural Resources Conservation Service, 312p.

Paylor, R.L., Florea, L.J., Caudill, M.J., and Currens, J.C., 2003, A GIS coverage of sinkholes in karst areas of Kentucky, in preparation, metadata and shapefiles of highest elevation closed contours, 1 CDROM.

Ray, Joseph A., and Currens, James C., 1998, Karst Ground-Water Basins in the Beaver Dam 30x60 Minute Quadrangle: Kentucky, Kentucky Geological Survey, Map and Chart 19, Series XI, Mapped scale 1:100,000.

Thompson, Mark F., Plauche, Stephen T., and Crawford, Matthew M., 2003, Geologic map of the Beaver Dam 30 x 60 minute quadrangle: Kentucky Geological Survey, ser. 12, Geologic Map 1, scale 1:100,000.

Woods, A.J., Omernik, J.M., Martin, W.H., Pond, G.J., Andrews, W.M., Call, S.M., Comstock, J.A., and Taylor, D.D., 2002, Ecoregions of Kentucky (color poster with map, descriptive text, summary tables, and photographs): Reston, VA., U.S. Geological Survey (map scale 1:1,000,000).

Copyright 2003 by the University of Kentucky, Kentucky Geological Survey. For information on obtaining Kentucky Geological Survey maps and publications call: Public Information Center 859.257.3896. 877.778.7827 (toll free). View the KGS World Wide Web site at: www.uky.edu/kgs