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Alluvium (Qa)
Topography
Alluvium forms floodplains along the larger streams.
Hydrology
Most wells in the alluvium are inadequate for a domestic supply.
Ste. Genevieve Limestone (Mgl)
Topography
The Ste. Genevieve Limestone underlies rolling and dissected karst areas.
Hydrology
This limestone 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.
Wells that do not intersect karst conduits generally are inadequate
for domestic use. 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 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 Limestone underlies rolling karst areas. It commonly has
less relief than karst in areas underlain by the Ste. Genevieve Limestone.
Resistant siltstone alternates with nonresistant shale layers to form
discontinuous minor benches on hillsides. The St. Louis forms steep
bluffs along the Barren River.
Hydrology
This limestone yields more than 50 gallons per minute 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 near major
streams are large where solution openings are penetrated, but most wells
near major streams are inadequate.
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 gallons per minute to more than 1,000
gallons per minute. The lower part of the formation is composed of siltstone
and argillaceous limestone. Yields from these sedimentary rocks are
low and generally not adequate for a domestic supply.
Salem and Warsaw Formations (Msh)
Topography
These formations underlie gentle to dissected rolling uplands. They
form steep bluffs where the limestone overlies rocks of Osagean age.
In some areas numerous small sinkholes occur in the formation.
Hydrology
These formations yield enough water for a domestic supply where they
are dominantly limestone and where solution openings are penetrated
near perennial stream level. Yields are low where siltstone or argillaceous
limestone is penetrated. Wells that penetrate large solution openings
and wells at the contact of the limestone with the underlying siltsotne
may produce more than 5 gallons per minute.
Minor spring horizons occur in the upper part and 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 Formations. Low flows generally are less than 5 gallons per minute.
Fort Payne Formation (Mbf)
Topography
The Fort Payne underlies dissected rolling uplands. It 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 the Fort Payne in lowland areas near streams produce enough
water for a domestic supply and may produce more than 5 gallons per
minute from solution openings. Most wells obtain water from perched
or semiperched 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 gallons per
minute, but most springs go dry in late summer or fall. Where shale
layers are conspicuous, most wells are inadequate for domestic use.
Where chert layers are thick and extensive, yields of more than 5 gallons
per minute may be obtained.
Chattanooga Shale (MDnb)
Topography
The Chattanooga Shale forms the lower part of steep valley sides and
steep slopes of tributary streams. Resistant layers form small discontinuous
ledges and minor waterfalls in streams.
Hydrology
This shale yields little or no water to wells. Seepage springs are present
at numerous horizons, but most go dry during late summer and fall.
Laurel and Brassfield Dolomites, Osgood Formation (Slb)
Topography
Dolomite beds form resistant ledges on valley sides.
Hydrology
These formations yield small quantities of water to wells near the Cumberland
River.
Louisville Limestone (Slw)
Topography
The Louisville underlies broad flat bottoms; small areas of karst are
formed in the upper part of the formation.
Hydrology
This limestone is a major spring horizon in Allen County. Several springs
have low flows of several thousand gallons per minute. Wells in lowland
areas bordering streams that encounter large solution channels yield
as much as the flow of some springs. Wells away from streams generally
yield sulfurous water or brines.
Cumberland Formation, Leipers Limestone, Catheys Formation (Ocl)
Topography
Limestone layers, interbedded with shales, form discontinuous ledges
along hillsides in some areas.
Hydrology
In lowland areas bordering large streams, yields are enough for a domestic
supply (more than 500 gallons per day). Elsewhere these rock bodies
yield little water to wells, but small quantities to springs. Deep wells
generally yield sulfurous water or brines.
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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