The NSS Bulletin - ISSN 1090-6924
Volume 38 Number 4: 99-105 - October 1976

A publication of the National Speleological Society

A Review of the Hydrogeology of the Central Kentucky Karst
John W. Hess


The Central Kentucky Karst represents one of the principal types of karst terrain in North America. This mature karst is developed in a sequence of Mississippian limestones 160 m in thickness that dips to the northwest at an average of 6 m km. Above the major basal limestone aquifier are several perched aquifers in and above the clastic caprock, of which the Haney limestone aquifer is most significant.

Four types of catchments, plus river backflooding, supply recharge to the basal springs; sinking streams, sinkhole areas, perched aquifers, and karst valleys. Vertical shafts, large cylindrical voids, rapidly transmit water downward through the vadose zone.

The aquifer has a large secondary porosity and permeability from fractures and bedding planes and a large tertiary permeability from extensive cavern development. The water table has a relatively high gradient of 9.9 m/km under the Sinkhole Plain and a relatively low gradient of 0.5 m/km under the Chester Cuesta. Its shape is determined by shale layers in the lower part of the cavernous limstone sequence.

The large Sinkhole Plain catchment drains to the north and discharges at two regional springs. The Chester Cuesta is drained by some 80 intermediate and local base-level springs. From Green River records and spring discharge data, it appears that all runoff from the Central Kentucky Karst south of the Green River discharges through conduit-flow springs. The two regional springs account for 80% of the discahrge south of the river.

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