Forms terraces and narrow flood plains of varying width along streams.
At least one well-developed
terrace is generally present.
Yields more than 100 gal/day to most dug wells. Probably will yield
as much as 20 or 25 gal/min to wells drilled and screened in the alluvium
of the lower sections of the Levisa Fork. Water is soft or moderately
hard; may contain large amounts of iron at depth.
Breathitt Group (Pbu, Pbm, Pbl) (Princess Formation, Four Corners
Formation, Hyden Formation, Pikeville Formation)
Underlies valleys and forms the rugged hills. Sandstones form narrow
valleys and cliffs or steep slopes on hillsides and shales form wide
valleys and moderate or gentle slopes on hills. Tops of hills and ridges
commonly are capped by sandstone.
Yields more than 500 gal/day to most of the wells drilled in valley
bottoms and half of the wells on hillsides, and smaller quantities of
water to wells on hilltops. 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. Ground water 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
The Grundy forms resistant sandstone underlies valleys.
The Grundy yields more than 500 gal/day to most wells drilled in valley
bottoms and half the wells on hillsides, with smaller quantities to
wells on hilltops. 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. Inter-granular openings yield water to joints, and probably
directly to some wells. Perched and semi-perched water tables are common.
Water is soft or moderately hard, and sometimes with noticeable iron.
Wells drilled below drainage level may yield salty water in some places.
The U.S. Geological Survey's Hydrologic
Atlas Series, published cooperatively with the Kentucky Geological
Survey, provides hydrologic information for the entire state.
to "Groundwater Resources in Kentucky"