Table 2. Aquifer and well characteristics in Tennessee (modified from Hollyday and Bradley, 1985)
[ft, foot; gal/min, gallon per minute]
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Aquifer name and description1 Well characteristics Remarks
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Depth (ft) Yield (gal/min)
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Common range May exceed Common range May exceed
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Alluvial: Sand, gravel, 10 - 75 100 20 - 50 1,500 High iron concentrations
and clay. Unconfined. in some areas.
Tertiary sand: Multi-aquifer 100 - 1,300 1,500 200 - 1,000 2,000 Includes Memphis Sand of
unit of sand, clay, silt, Claiborne Group and
and some gravel and lignite. Fort Pillow Sand of
Confined; unconfined Wilcox Group. Problems
in the outcrop area. with high iron concen-
trations in some places.
Cretaceous sand: Multi-aquifer 100 - 1,500 2,500 50 - 500 1,000 Includes McNairy and
unit of interbedded sand, Coffee Sands, and
clay, marl, and gravel. Tuscaloosa Formation.
Confined; unconfined Water withdrawn
in the outcrop area. primary in the outcrop
area.
Pennsylvanian sandstone: Multi- 100 - 200 250 5 - 50 200 Permeability is from
aquifer unit, primarily fractures, faults, and
sandstone and conglomerate, bedding-plane openings.
interbedded shale and some Principal water-bearing
coal. Unconfined near land units are Rockcastle
surface; confined at depth. and Sewanee Conglomerates.
High iron concentrations
are a problem.
Mississippian carbonate rock: 50 - 200 250 5 - 50 400 Water occurs in solution and
Multi-aquifer unit of bedding-plane openings.
limestone, dolomite, and Principal water-bearing
some shale. Unconfined or units are Ste.Genevieve
partly confined near land (Monteagle), St. Louis
surface; may be confined and Warsaw Limestones and
at depth. Fort Payne Formation.
Water generally hard;
high iron, sulfide, or
sulfate concentrations
are a problem in some
areas.
Ordovician carbonate rock: 50 - 150 200 5 - 20 300 Principal water-bearing
Multi-aquifer unit of units are Bigby, Carters,
limestone, dolomite, and Ridley, and Murfreesboro
shale. Partly confined to Limestones. Water gen-
unconfined near land surface; erally hard; some high
confined at depth. sulfide or sulfate
concentrations in places.
Knox: Primarily dolomite, some 700 - 1,200 1,400 1 - 10 20 Deep aquifer; occurs under
limestone; confined. Does not most of central and
have the structural complexity western Tennessee. Away
of the Cambrian-Ordovician from Central Basin, water
carbonate aquifer. generally has high
concentrations of
dissolved solids.
Cambrian-Ordovician carbonate 100 - 300 400 5 - 200 2,000 Principal water-bearing
rock: Extremely faulted multi- units are carbonate rocks
aquifer unit of limestone, in Chickamauga Limestone,
dolomite, sandstone, and Knox Group, and Honaker
shale; structurally complex. Dolomite. Water is
Unconfined; confined at depth. generally hard. Brine is
present below 3,000 feet.
Crystalline rock: Multi-aquifer 50 - 150 200 5 - 50 1,000 High yields occur primarily
unit of dolomite, granite in dolomite or deep
gneiss, phyllite, and colluvium and alluvium.
metasedimentary rocks Shady Dolomite is a
overlain by thick regolith; principal aquifer. Low pH
alluvium and colluvium and high iron concentra-
in some valleys. Generally tions may be problems in
unconfined. some areas.
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1Refer to figure 1 for location map.
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