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Alluvium (Qa)
Topography
Alluvium forms terraces and flood plains along the Green river and tributaries.
Hydrology
Most wells furnish less than 100 gal/day (gallons per day), inadequate
for a domestic supply. In Hart County course sand and gravel may occur
in the alluvium where rocks of Pennsylvanian age are close to streams.
Wells penetrating these deposits will produce as much as about 50 gal/min
(gallons per minute).
Caseyville Formation (Pca)
Topography
The Caseyville forms dissected uplands and ridgetops near Green River.
Hydrology
Wells in uplands generally are inadequate (yield less than 100 gal/day)
for a domestic supply.
Buffalo Wallow Formation, Leitchfield Formation, Tar Springs Sandstone
(Mcu)
Topography
These formations form gently rolling uplands and fairly steep slopes
adjacent to stream valleys. Sandstone lenses, some massive, form small
benches.
Hydrology
These rocks yield little or no water.
Glen Dean Limestone, Hardinsburg Sandstone (Mcl)
Topography
These formations underlie dissected uplands and forms moderate slopes
in Hart County.
Hydrology
Most wells in upland areas are inadequate for domestic supply, yielding
little or no water.
Golconda Formation (Haney Limestone, Big Clifty Sandstone, Beech
Creek Limestone
Members) (Mcl)
Topography
Limestone underlies gently rolling to flat uplands and forms bluffs
near heads of valleys. The Big Clifty sandstone forms the Dripping Springs
Escarpment, several hundred feet high.
Hydrology
Deep wells that penetrate the sandstone formations near perennial stream
level may produce enough for a domestic supply (more than 500 gal/day).
Close to outcrop areas, particularly near major escarpments, yields
from perched water bodies generally are low and not dependable. Minor
spring horizons occur on discontinuous layers of shale near the base
of the sandstones. The most conspicuous springs are those that discharge
from the base of the Big Clifty sandstone. These are the “dripping
springs” of the Dripping Springs escarpment. Many of these springs
go dry during the late fall and summer, and very few are adequate for
a domestic supply. Limestone formations yield small to adequate supplies
from solution openings. In lowland areas bordering streams, some wells
produce enough for a domestic supply. Many springs occur at the base
of the limestones where they crop out on escarpments and hillsides.
Girkin Formation (Reelsville Limestone, Sample Sandstone, Bever
Bend and Paoli Limestone)
(Mcl)
Topography
The Girkin forms the lower part of the Dripping Springs escarpment.
The lower part of the Girkin underlies rolling karst areas near base
of escarpment. The formation contains numerous large sinks into which
the overlying sandstone has collapsed.
Hydrology
Most wells in upland areas are inadequate for domestic use, however
some wells yield enough water for a domestic supply (more than 500 gal/day)
from solution openings. Some wells produce more than 5 gal/min from
large solution openings. Near outcrop areas, particularly near major
escarpments, yields generally are inadequate during dry periods.
Ste. Genevieve Limestone (Mgl)
Topography
The Ste. Genevieve underlies rolling karst areas, and forms steep bluffs
near Green River. Part of the caverns of Mammoth Cave are developed
in this formation.
Hydrology
The Ste. Genevieve yields more than 50 gal/min to wells from large solution
openings in karst areas. Most wells penetrate solution openings, but
in areas high above perennial streams these solution openings are dry
in late summer and fall, and many wells are inadequate. Wells that do
not intersect karst conduits generally are inadequate for domestic use.
The Ste. Genevieve contains major caverns of Mammoth Cave area, which
have large connected subsurface streams. Springs having low flows ranging
from less than 10 gal/min to more than 1,500 gal/min occur at or near
stream level or near contact with the underlying St. Louis limestone.
St. Louis Limestone (Mgl)
Topography
The St. Louis underlies rolling karst areas. It commonly has less relief
than karst in areas underlain by the Ste. Genevieve Limestone. Resistant
siltstone and non-resistant shale layers form discontinuous minor benches
on hillsides.
Hydrology
The St. Louis yields more than 50 gal/min to wells from large openings
in karst areas. Most wells penetrate some solution openings, but where
openings are small or high above perennial streams, yields are often
inadequate for domestic supply. Yields of wells close to major streams
are large where solution openings are penetrated. A major spring horizon
occurs near the top of the formation in the karst areas. Many seepage
springs occur throughout the formation; low flows range from less than
10 gal/min to more than 1,000 gal/min. The lower part of the formation
is composed of siltstone and argillaceous limestone. Yields from these
sedimentary rocks are low and generally are not adequate for a domestic
supply.
Salem, Warsaw, Harrodsburg Formations (Msh)
Topography
These formations underlie gently rolling uplands. They form steep bluffs
where the limestone overlies rocks of Osage age. In some areas numerous
small sinkholes occur in the Warsaw.
Hydrology
These rocks yield enough water for a domestic supply where the formations
are dominantly limestone and close to perennial stream level. Yields
are low where siltstone or argillaceous limestone is penetrated. Minor
spring horizon occurs at the contact of the limestone with the underlying
siltstone or argillaceous limestone. Another spring horizon occurs near
the contact of the Warsaw and Fort Payne. Low flows generally are less
than 5 gal/min.
Fort Payne Formation (Mbf)
Topography
The Fort Payne underlies dissected rolling uplands, and forms steep
valley sides in maturely dissected topography. Small valleys are steep
and V-shaped. Siltstone and chert form discontinuous ledges on hillsides.
Hydrology
Wells in lowland areas close to streams produce enough water for a domestic
supply and may produce more than 5 gal/min from solution openings. Most
wells obtain water from perched or semi-perched water bodies supported
by discontinuous shale layers, and many are dry during late summer and
fall. Minor spring horizons occur throughout the formation. Flows are
as much as 30 gal/min, but most go dry in late summer or fall. Where
shale layers are conspicuous or when the formation consists predominantly
of siltstone, most wells are inadequate for domestic use (less than
100 gal/day). Where chert layers are thick and extensive in area, yields
of more than 5 gal/min may be obtained.
The U.S. Geological Survey's Hydrologic
Atlas Series, published cooperatively with the Kentucky Geological
Survey, provides hydrologic information for the entire state.
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