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Alluvium and Glacial Outwash Sediments (Qa)
Topography
These sediments form floodplains, valley bottoms, and terraces of the
Cumberland, Tennessee, and Ohio Rivers and tributaries. Valley-train
deposits occur beneath terraces along the Ohio River.
Hydrology
The sediments yield several hundred gallons a minute to drilled wells
in the Ohio River Valley and its two main tributaries, the Cumberland
and Tennessee River Valleys. The sediments yield enough water for a
modern domestic supply (more than 500 gallons per day) to nearly all
wells. Locally, north of Smithland, wells must penetrate the underlying
bedrock to obtain an adequate supply. The sediments yield practically
no water to wells in small valleys where the alluvium is thin and fine-grained.
Water ranges in hardness from 12 to 664 parts per million and in dissolved
solids from 53 to 1,220 parts per million. Iron may be present in objectionable
amounts.
Loess
Topography
Loess forms a thin mantle over alluvial deposits and bedrock over much
of the area near the Ohio River.
Hydrology
Although not an aquifer, it yields small amounts of water to a few wells.
When saturated by rainfall, it transmits water to underlying aquifers.
Terrace Gravel Deposits (Qtc)
Topography
These deposits occur on uplands and eroded edges of uplands above 370
feet.
Hydrology
The sediments yield small quantities of water suitable for household
use. One spring had measured discharge of 47 gallons per minute. Most
wells yield less than 10 gallons per minute. The deposits yield sufficient
water west of Paducah for industrial demand; maximum yields are on the
order of 1,000 gallons per minute. Water-bearing gravel usually overlies
clay or indurated layers. Water ranges in hardness from 8 to 724 parts
per million, and in dissolved solids from 43 to 782 parts per million.
Iron content is generally low.
Porters Creek Clay (Tp)
Topography
The Porters Creek Clay crops out along Clarks River Valley and in adjacent
uplands from the Tennessee state line to Paducah.
Hydrology
The Porters Creek Clay probably will yield a little water from joints
and from sandstone dikes. Water is probably hard and high in iron. The
formation is important as a confining layer.
Clayton and McNairy Formations (TKcm)
Topography
These formations occur in uplands and dissected ridges.
Hydrology
These formations yield sufficient water for domestic use near the outcrop
area of Paleozoic bedrock and in areas of perched water. Where the formation
is thick, drilled wells yield as much as 830 gallons per minute. In
areas where the formation is mostly silt and clay, there may not be
sufficient saturated sand to furnish even a domestic supply. Hardness
of water ranges from 13 to 182 parts per million, and dissolved solids
from 62 to 275 parts per million. Iron may be present in objectionable
amounts.
Tuscaloosa Formation (Kt)
Topography
The Tuscaloosa may occur in remnants of a channel eroded into the surface
of the Paleozoic rocks. It underlies dissected ridges adjacent to Kentucky
Lake.
Hydrology
The Tuscaloosa is not significant as an aquifer. Most drilled wells
in the gravel of the Tuscaloosa are adequate for a bailer (more than
100 gallons per day). Yields are low, because of a clayey matrix and
poor sorting. Tripolitic clay is present locally, which tends to clog
well screens, and wells penetrating it are inadequate (less than 100
gallons per day). Hardness of water from two wells sampled was 26 and
57 parts per million, and dissolved solids, 50 and 76 parts per million.
Yields adjacent to Kentucky Lake may exceed 5 gallons per minute.
Chert Rubble
Topography
Chert occurs mostly in the subsurface around the periphery of the embayment;
its extent beneath the embayment is not known. The surface of the Paleozoic
rocks has been locally reduced to a chert rubble by pre-Late Cretaceous
weathering of the chert-bearing limestone.
Hydrology
The chert rubble probably will yield more than enough water for domestic
use; locally, it may yield sufficient water for small public supplies.
Yields are as large as 100 gallons per minute. Yields vary with the
saturated thickness of the rubble and characteristics of the rubble’s
matrix. Hydrologic properties resemble those of gravel. The water level
in the rubble slopes downward from highs on the limestone surface toward
collapse structures (areas of thick chert rubble formed by solutional
collapse along fracture zones and former drainage channels). The water
is soft and has a low content of dissolved solids, but may contain an
objectionable amount of iron, which probably is derived from the iron-rich
clay that commonly fills voids in the rubble.
Lamprophyre Dikes and Sills (Pl)
Hydrology
This unit is not considered an aquifer.
Caseyville Formation (Pca)
Topography
The Caseyville forms dissected uplands in the northeastern corner of
the county. It also occurs in downfaulted blocks of the fluorspar area.
Hydrology
The Caseyville will yield enough water for a modern domestic supply
to most wells in lowland areas bordering streams, and locally in broad
upland areas. Wells in small upland areas generally are inadequate (less
than 100 gallons per minute).
Chesterian Formations (Kinkaid Limestone, Degonia Sandstone, Clore
Limestone, Palestine
Sandstone, Menard Limestone, Waltersburg Sandstone, Vienna Limestone,
Tar Springs
Sandstone, Glen Dean Limestone, Golconda Formation, Cypress Sandstone,
Paint Creek Shale, Bethel Sandstone)
Hydrology
In most areas of the county, wells and springs in outcrop areas yield
small amounts of water. Water from Mississippian rocks underlying younger
rocks contain salt in objectionable amounts if any water is found.
In the southern edge of the county, most drilled wells that obtain
water from fault zones are adequate for a domestic supply. Yields are
as much as 100 gallons per minute. Flows of as much as 20 gallons per minute are obtained
from fractures along fault zones and adjacent beds. Most flowing wells
are in sandstone. Water is usually obtained from the hanging walls or
gouge zones of faults. Most shallow wells in broad uplands are dug and
usually yield more than 100 gallons per day, but yields are not dependable in
dry years. Most drilled wells produce enough water for residential use.
Minor spring horizons occur near the base of the sandstone on discontinuous
shale beds. Very few of the springs are adequate for a domestic supply,
and many go dry in late fall or winter.
Limestone formations yield small to adequate supplies from solution
openings. In lowland areas bordering streams, some wells furnish enough
for a domestic supply. Most wells in upland areas are inadequate for
a domestic supply. On uplands, deep wells that penetrate solution openings
in limestone may produce more than 5 gallons per minute, but most deep
wells on uplands are inadequate for a domestic supply. Close to outcrop
areas, particularly near major escarpments, yields from perched water
bodies generally are inadequate during dry periods. Springs occur at
the base of many limestone formations where they crop out on escarpments
and hillsides. Adjacent to large upland areas, springs yield as much
as 100 gallons per minute, and low flows are more than 5 gallons per
minute from some springs.
Kinkaid Limestone, Degonia Sandstone, Clore Limestone (Mcu)
Topography
In the far eastern part of the county, these formations underlie gently
rolling uplands having some sinkholes and fairly steep slopes.
Palestine Sandstone (Mcu)
Topography
The Palestine sandstone forms a minor bench on hillsides, and underlies
gently rolling uplands.
Menard Limestone, Waltersburg Sandstone, Vienna Limestone (Mcu)
Topography
These rocks underlie flat uplands and form gentle slopes on hillsides.
Tar Springs Sandstone (Mcu)
Topography
The Tar Spring Sandstone underlies gently rolling uplands, and forms
a minor bench on hillsides.
Glen Dean Limestone (Mcl)
Topography
The Glen Dean Limestone underlies gently rolling uplands, and forms
a gradual slope above the Hardinsburg bench.
Hardinsburg Sandstone (Mcl)
Topography
The sandstone forms a minor escarpment, modified in many places by faults.
It also underlies
broad rolling uplands.
Golconda Formation (Haney Limestone, Big Clifty Sandstone, Beech
Creek Limestone
Members) (Mcl)
Topography
These rocks underlie gently rolling uplands, and form steep slopes below
the minor Hardinsburg
Sandstone escarpment.
Cypress Sandstone (Mcl)
Topography
The sandstone forms a major escarpment, but is broken by faults in the
fluorspar district. This sandstone also underlies broad, flat uplands.
Paint Creek Shale (Mcl)
Topography
The shale forms moderate to rolling slopes below the Cypress Sandstone
escarpment; it has been modified by faults in the fluorspar district.
Bethel Sandstone (Mcl)
Topography
The Bethel forms the lowest major escarpment in the fluorspar district;
the escarpment is broken by faults in the fluorspar district. The Bethel
underlies broad rolling uplands.
Renault Limestone (Mcl)
Topography
The Renault forms a moderate slope under the Bethel Sandstone escarpment,
except where it has been modified by faults or a higher sandstone escarpment.
Hydrology
The Renault yields little or no water to wells. Small springs with low
flows of about 5 gallons per minute occur near the top of the formation.
Ste. Genevieve Limestone (Levias Limestone, Rosiclare Sandstone,
Fredonia Limestone
Members) (Mgl)
Topography
The Ste. Genevieve underlies rolling karst uplands. It forms moderate
slopes under the Bethel Sandstone escarpment, except where it has been
modified by faults. The Ste. Genevieve is exposed across large fault
blocks in parts of the fluorspar district.
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, and many wells are inadequate.
Springs having low flows ranging from less than 10 gallons per minute
to about 1,500 gallons per minute occur at or near stream level. Smaller
springs discharge from perched water bodies in the upland area, but
many go dry during late summer and fall.
St.Louis Limestone (Mgl)
Topography
The St. Louis underlies dissected uplands and ridges. It underlies rolling
karst upland in faulted parts of the fluorspar district. It forms steep
valley walls along the Cumberland River.
Hydrology
Low flows of numerous springs that discharge from near the top of the
formation and near stream level range from less than 10 gallons per minute to about
1,500 gallons per minute. Maximum flows range from less than 100 gallons per minute to more
than 100,000 gallons per minute. Most springs are situated near minor rivers. In
karst areas, drilled wells generally produce enough water for domestic
use. Some produce more than 50 gallons per minute from large solution openings.
Most wells high above perennial streams are adequate.
In nonkarst areas, yields generally are lower than in karst areas.
The number of solution openings is fewer and their size smaller. Many
wells are insufficient for domestic use. Most springs are small, and
many go dry during late summer and fall. Most wells high above perennial
streams are inadequate.
Warsaw Limestone (Mw)
Topography
The Warsaw underlies dissected uplands and ridges adjacent to the Cumberland
River and tributaries in Livingston County.
Hydrology
Wells that encounter large solution openings near stream level or near
sinkholes yield sufficient water for a domestic supply with a power
pump. In most other areas, the rock is fine-grained, and yields generally
are insufficient for a bailer or bucket (less than 100 gallons per day).
Fort Payne Formation (Mbf)
Topography
The Fort Payne underlies dissected ridges between the Tennessee and
Cumberland Rivers.
Hydrology
The Fort Payne yields almost no water to wells where it is unweathered.
Where the limestone has been leached away and chert rubble is left,
yields may exceed 50 gallons per minute. Yields of most wells of moderate
depth range from 2 to 10 gallons per minute. Tripolitic clay may be
present in some areas where the formation yields little or no water
to wells.
The U.S. Geological Survey's Hydrologic Atlas Series, published cooperatively
with the
Kentucky Geological Survey, provides hydrologic information for the
entire state. Atlases for the
county are HA-34,
HA-129.
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