Karst Occurrence in Kentucky

Karst is a terrane that is generally underlain by limestone or dolomite, where the topography is formed chiefly by dissolving rock. Karst landscapes are commonly characterized by sinkholes, sinking streams, closed depressions, subterranean drainage, large springs and caves.

Karst regions are susceptible to unique problems such as sinkhole collapse, sinkhole flooding and rapid groundwater pollution. Springs in karst areas are an important, productive source of groundwater. Rare biologic communities and endangered species can be found in the fragile underground environments developed in karst landscapes.

Click here to view a map that shows areas in Kentucky where Karst occurs.

Sinkholes:

Typically found in limestone areas, sinkholes are depressions or soil collapses, often circular in shape, which accelerate the damage that typical surface runoff can cause.

Sinkholes provide a direct path or funnel for pollutants like untreated sewage or soil contaminants to drain into underground waterways. A swallet, or drain hole is the point where runoff water leaves the surface and rapidly flows underground with little or no filtration. Sinkholes are only the most obvious feature of karst terrane.

The entire karst area, including flat areas between sinks, tends to be sensitive to pollution. Land-disrupting activities like logging, farming and development often trigger soil and sinkhole collapses. In general, groundwater degradation from harvesting activities is increased when a sinkhole contains steeper slopes and more bedrock outcrops. During the PreHarvest planning, be sure to identify and flag all sinkhole areas.

Sinkhole checklist: 

  • Identify and flag all karst areas and sinkholes. 
  • Avoid harvesting near sinkholes if possible. Healthy tree roots help stabilize sinkhole slopes. If the area cannot be avoided, maintain good buffer area around sinkhole (see chart on the previous page). Keep all tree tops, slash, runoff and debris from roads, skid trails and log landings away from sinkhole buffer. 
  • Avoid harvesting on slopes greater than 30% (~3 ft. drop per 10 foot slope) in areas with sinkholes.
  • Keep equipment fluids, pesticides and fertilizers out of sinkhole areas.
photo illustration: Sara Thilman and Joe Ray
 

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