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Breathitt Group (Pbu, Pbm, Pbl)/Conemaugh Formation (Pmc) (Princess
Formation, Four Corners Formation, Hyden Formation, Pikeville Formation):
In eastern Elliott County
Topography
Sandstones form narrow valleys and cliffs or steep slopes on hillsides,
and shales form wide valleys and moderate or gentle slopes on hills.
The tops of hills and ridges commonly are capped by sandstone.
Hydrology
In this area the Breathitt yields more than 500 gallons per day to most
wells drilled in valley bottoms and half of the wells on hillsides,
and smaller quantities of water to wells on hilltops. The most common
aquifers are sandstone and shale, but coal supplies water to a few wells.
Near-vertical joints and openings along bedding plains yield most of
the water to wells. Waters are highly variable in chemical character.
May contain salty water at depths less than 100 feet below the principal
valley bottoms.
Breathitt Group (Pbu, Pbm, Pbl) (Princess Formation, Four Corners
Formation, Hyden Formation, Pikeville Formation): In western
and central Elliott County
Topography
The topography of the Breathitt is rugged in this area; sandstone forms
narrow valleys and cliffs or steep slopes on hillsides, and shale forms
wide valleys and moderate or gentle slopes on hills. The tops of hills
and ridges commonly are capped by sandstone.
Hydrology
In this area the Breathitt yields more than 500 gallons per day to almost
half the wells in valley bottoms, but very little to wells on hillsides
and hilltops. The most common aquifers are sandstone and shale, but
coal supplies water to a few wells. Near-vertical joints and openings
along bedding plains yield most of the water to wells. Waters are highly
variable in chemical character. They may contain salty water at depths
less than 100 feet below the principal valley bottoms.
Grundy Formation (contains Lee-type sandstone of the former Lee
Formation) (Plc)
Topography
The upper Grundy erodes easily, forming broad, flat ridges. The lower
part, more conglomeratic and resistant, forms steep walls high on the
sides of ridges. Some cliff-forming sandstone paleochannels cut through
the Paragon into Late Mississippian limestone.
Hydrology
The Grundy yields more than 500 gallons per day to most wells drilled
in broad valley bottoms, and smaller quantities of water to wells on
hillsides and hilltops. It yields 100 to 500 gallons per day on some
wide ridges, where water may be semiperched in sandstone on top of fireclay
that impedes downward percolation of water. Sandstone is the principal
aquifer, but shale yields water to some wells and coal to a few. Vertical
joints and openings along bedding planes, best developed in sandstones,
supply most of the water to wells. Intergranular openings yield water
to joints, and probably directly to some wells. Perched and semiperched
water tables are common. Waters are soft to moderately hard, and sometimes
contain noticeable amounts of iron, but generally have a low dissolved-solids
content.
Slade Formation (Mn)
Topography
The Slade underlies valleys in Elliott County. Limestone beds form steep
hillsides and prominent bluffs in sides of ridges and knobs that are
capped by Pennsylvanian rocks. Massive limestone forms cliffs and solution
features: sinkholes, caves, and hanging valleys.
Hydrology
The Slade yields more than 500 gallons per day to over half of the wells
drilled in valley bottoms and to many wells drilled on hills. It yields
little water where overlain by Pennsylvanian rocks. The Slade may yield
more than 50 gallons per minute to a few wells penetrating large solution
cavities in limestone, the most common aquifer. Sandstone and shale
yield water from fractures to a few wells. Springs are common, particularly
at the head of streams; some from solution cavities near stream level
flow as much as 100 gallons per minute. Springs have large winter and
small summer flows. Water is hard.
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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