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Alluvium (Qa)
Topography
Alluvium forms terraces and floodplains along the Green River and tributaries.
Hydrology
The alluvial sediments may yield as much as 100 gallons per minute from
sands and gravel along the Green River. Most wells in thin alluvium
furnish less than 100 gallons per day, inadequate for a domestic supply.
Coarse sand and gravel may occur in the alluvium where rocks of Pennsylvanian
age are close to streams. Water is hard.
Caseyville Formation (Pca)
Topography
The Caseyville underlies rolling uplands and forms dissected uplands
and ridgetops near the Green River.
Hydrology
Yields of 60 gallons per minute have been obtained from thick sandstone
beds. The Caseyville will yield enough water for a modern domestic supply
to most wells penetrating sandstone. At depth, the water becomes salty
or may have a high sodium bicarbonate content. Electric logs indicate
that moderately mineralized water may be obtained locally from this
formation at depths of 1,200 feet.
Buffalo Wallow Formation, Leitchfield Formation, Tar Springs Sandstone
(Mcu)
Topography
These rock bodies 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
The Glen Dean underlies gently rolling to level uplands. The uplands
are dissected along the perimeter of the Dripping Springs Escarpment.
Limestone forms steep slopes above benches of the underlying sandstone.
Sandstone forms small discontinuous benches on hillsides.
Hydrology
These formations yield little or no water; most wells in upland areas
are inadequate for a domestic supply.
Golconda Formation (Haney Limestone, Big Clifty Sandstone, Beech
Creek Limestone Members) (Mcl)
Topography
The Golconda limestone underlies gently rolling to flat uplands and
forms bluffs near heads of valleys. The Big Clifty Sandstone caps a
major escarpment (Dripping Springs Escarpment) several hundred feet
high, and underlies gently rolling uplands.
Hydrology
Deep wells that penetrate the sandstone formations near perennial stream
level may produce enough for a domestic supply (more than 500 gallons
per 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, Beaver
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 the
base of the escarpment. The Girkin contains numerous large sinks into
which the overlying sandstone has collapsed. Upper Mammoth Cave passages
are developed within the lower beds of the Girkin Formation.
Hydrology
Most wells in upland areas are inadequate for domestic use; however,
some wells yield enough water for a domestic supply (more than 500 gallons
per day) from solution openings. Some wells produce more than 5 gallons
per minute 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 the Green River. Part of the caverns of Mammoth Cave are developed
in this formation.
Hydrology
The Ste. Genevieve yields more than 50 gallons per minute 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, making many wells inadequate.
Wells that do not intersect karst conduits generally are inadequate
for domestic use. The Ste. Genevieve contains major caverns of the Mammoth
Cave area, which have large connected subsurface streams. Springs having
low flows ranging from less than 10 gallons per minute to more than
1,500 gallons per minute occur at or near stream level or near the contact
with the underlying St. Louis Limestone. Smaller springs discharge from
perched water bodies in upland areas, but many go dry during late summer
and fall.
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, but sinkholes
are steeper. The St. Louis forms steep bluffs along the Barren River.
The lowest passages of Mammoth Cave are mostly developed within this
formation.
Hydrology
The limestone yields more than 50 gallons per minute to wells from large
openings in karst areas. Most wells penetrate some solution openings,
but in high areas above perennial streams, yields are often inadequate
for a domestic supply. Yields of wells close to major streams are large
where solution openings are penetrated, but most wells near major streams
are inadequate. The St. Louis is a major spring horizon, with many springs
flowing several hundred to several thousand gallons a minute. Many springs
are used for public and industrial water supplies.
Warsaw Limestone (Msh)
Topography
The Warsaw underlies gently rolling uplands.
Hydrology
Wells that penetrate large solution openings in the Warsaw may produce
more than 5 gallons per minute.
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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