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Alluvium (Qa)
Topography
The alluvium forms floodplains, valley bottoms, and terraces of the
Cumberland and Tennessee Rivers and tributaries.
Hydrology
Alluvium yields several hundred gallons a minute to drilled wells in
the Ohio, Cumberland, and Tennessee River Valleys. It yields enough
water for a modern domestic supply (more than 500 gallons per day) to
nearly all wells. It yields 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.
Terrace Gravel Deposits and Continental Deposits (Qtc)
Topography
These deposits occur on uplands and eroded edges of uplands above 370
feet.
Hydrology
These deposits 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. Water-bearing gravel usually overlies clay or
indurated layers.
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 the 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 content was 50 and 76 parts
per million. Yields adjacent to Kentucky Lake may exceed 5 gallons per
minute.
Chert Rubble
Topography
Chert rubble occurs mostly in the subsurface. The surface of the Paleozoic
rocks locally has been reduced to a chert rubble by pre-Late Cretaceous
weathering of the chert-bearing limestone.
Hydrology
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 dissolved solids content, but may contain an objectionable
amount of iron, which probably is derived from the iron-rich clay that
commonly fills voids in the rubble.
Ste. Genevieve Limestone (Levias Limestone, Rosiclare Sandstone,
Fredonia Limestone
Members) (Mgl)
Topography
These rocks underlie rolling karst uplands. They form moderate slopes
under the Bethel Sandstone escarpment, except where they have been modified
by faults. They are 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 and Salem Limestone (Mgl)
Topography
The limestone underlies dissected uplands and ridges. It underlies rolling
karst uplands 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 Lyon County. It is exposed in fault blocks
at Kuttawa.
Hydrology
Wells that encounter large solution openings near stream level or near
sinkholes yield sufficient water for 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. It is exposed in a fault scarp at Kuttawa.
Hydrology
The Fort Payne yields almost no water to wells where 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.
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