The alluvium forms valley flats, flood plains, and, in the Kentucky
River valley, terraces. Flats are dissected by short, steep-sided gullies
The alluvium yields small to large quantities of water to drilled wells,
according to texture and thickness of material. It yields more than
20 gal/min (gallons per minute) from 60 feet of finegrained material
in the Kentucky River valley. It is too thin and fine-grained elsewhere
to yield large amounts of water. Water is hard.
Laurel Dolomite (Slb)
The Laurel forms ledges and cliffs along streams.
The Laurel yields 100 to 500 gal/day to wells on broad ridges and along
streams. It also yields water to small springs at contact with underlying
Osgood formation. Water is hard.
Osgood Formation (Slb)
The Osgood forms slopes between ledges above and below.
The Osgood yields almost no water from shale, but does yield water to
seeps from limestone; impedes recharge to underlying rocks. Water is
Brassfield Formation (Slb)
The Brassfield forms ledges on slopes and tops of small cliffs of underlying
The Brassfield yields almost no water to wells, but does yield water
to seeps and small springs. Water is hard.
Drakes Formation (Saluda Dolomite, Bardstown, Rowland Members) (Od)
& Bull Fork
These formations provide moderately dissected upland areas, with moderately
steep slopes where shale predominates and less steep slopes where limestone
predominates. Steep slopes occur along large streams and cliffs, many
slopes dotted with weathered limestone slabs. Solutional features are
evident where thick limestone beds underlie streams.
The Drakes and Bull Fork yields 100 to 500 gal/day to wells in large
stream valleys, and more where thick limestone is present. They yield
almost no water to wells on hillsides and ridges except in broad ridges
in upper part of formation, but do yield water to small springs. Water
is hard and may contain salt in valley bottoms but generally of good
Grant Lake Limestone, Fairview Formation , Calloway Creek Limestone
These rocks form gently to moderately rolling upland away from major
streams; more highly dissected where shale content increases; small
sinkholes, minor underground drainage, and broad, flat valleys where
limestone predominates. The lower part forms broad, flat ridges between
steep-sided valleys cut into underlying shale of the Kope or Clays Ferry
These rocks yield 100 to 500 gal/day to drilled wells in broad valleys
and along streams in uplands, and more than 500 gal/day from thick limestone
beds in the broad valley bottoms. The rocks yield almost no water to
drilled wells on hillsides or ridgetops, but do yield water to small
springs and seeps. Limestone bed 15 feet thick in lower part of the
Grant Lake Limestone yields as much as 30 gal/min to springs. Sandy
zone near base yield little water. Water is hard and in valley bottoms
may contain salt or hydrogen sulfide.
Clays Ferry Formation Okc) and Kope Formation (Okc)
These rocks form rugged topography of narrow, steep-sided ridges with
narrow V-shaped valleys of dendritic drainage. Shales on steep slopes
erode easily and are covered with thin limestone slabs in many places.
The contrast with the less rugged surface of the adjacent areas is marked
except near major streams. In the lower part of the formation topography
becomes more gently to moderately rolling uplands, with small sinkholes
and some underground drainage where limestone predominates.
These rocks yield 100 to 500 gal/day to drilled wells in large valley
bottoms along streams, but almost no water to drilled wells on hillsides
or ridgetops; yields water to small springs and seeps. Water is hard
in valley bottoms may contain salt or hydrogen sulfide.
Lexington Limestone (Millersburg Member, Tanglewood Limestone, Sulfur
Grier, Logana Members) (Ol)
The Lexington lies at the base of bluffs in valley bottoms along the
Kentucky River and large tributaries.
The Lexington yields more than 500 gal/day to wells in valley bottoms
and 100 to 500 gal/day to wells in small valleys. It also yields water
to springs. Water is hard and may contain salt or hydrogen sulfide in
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"