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Alluvium (Qa), Glacial Sediments (Qg)
Topography
These sediments form the floodplains and terraces of the Ohio and Licking
River Valleys and tributaries. Highest terraces are about 100 feet above
normal pool level of the Ohio River. The sediments are too thin in tributary
valleys to have distinctive topography.
Hydrology
These unconsolidated materials yield moderate to large quantities of
water to drilled wells in the Ohio River valley, according to thickness
and texture of the valley fill and type of well 200 to 500 gallons per
minute to ordinary tubular wells and as much as 1,000 gallons per minute
to gravel-packed wells. Yields are more than 3 million gallons per day
during the summer in the Covington-Newport area of the valley. The sediments
yield little water from fine-grained material. Drilled wells in the
Licking River Valley yield small to moderate amounts of water; most
wells yield more than 500 gallons per day. Water is hard and near the
valley walls of the Ohio and Licking Rivers may have a high iron content.
Wells that penetrate the alluvium and enter bedrock obtain little additional
water, and this water may contain objectionable amounts of salt or hydrogen
sulfide.
Bull Fork Formation (Ob)
Topography
The Bull Fork forms gently to moderately rolling uplands where limestone
predominates; it is more dissected where shale predominates.
Hydrology
The Bull Fork yields 100 to 500 gallons per day to wells in valleys or on broad
ridges, but almost no water to drilled wells on narrow ridges or hilltops.
It does yield water to dug wells and to small springs. Water is hard
and of good quality.
Grant Lake Limestone/Fairview Formation (Oaf)
Topography
These formations create gently to moderately rolling uplands away from
major streams such as the Ohio and Licking Rivers. They form steep,
dissected slopes along large streams, with ledges of thick limestone
beds on steep hillsides and bluffs, and moderately dissected uplands
where shale content increases. Streams in uplands produce broad, flat
valleys where thick limestone beds are present, and may have small sinkholes
with minor underground drainage. Low hills on uplands also may be capped
by thick limestone beds. The lower part forms broad, flat ridges between
steep-sided valleys cut into the underlying shale of the Kope Formation.
Hydrology
These rocks yield 100 to 500 gallons per day to drilled wells in valley
bottoms and along streams on uplands; they yield more than 500 gallons
per day from thick limestone beds in broad valley bottoms, and almost
no water to wells on hillsides or hilltops. They may yield some water
to dug wells on ridgetops, and some water to small springs. Small perennial
springs are in limestone in the lower Grant Lake Limestone. Water is
hard and in valley bottoms may contain salt or hydrogen sulfide. The
relatively impermeable shale prevents circulation of large quantities
of groundwater in joints and bedding-plane openings of underlying limestone.
As a result, the limestone beds have few solutionally enlarged openings,
and little water is available to wells and springs. Near the base of
the Grant Lake there is 25 feet or more of limestone with small amounts
of shale (Bellevue Limestone Member), however. Where this limestone
occurs at and below stream level in valley bottoms or along streams
on the uplands, fractures and bedding-plane openings have been enlarged
by solution; many small springs flow from outcrops, and some drilled
wells along streams yield more than 500 gallons per day.
Kope Formation (Okc)
Topography
The Kope forms rugged, much-dissected topography of long, narrow, steep-sided
ridges and narrow, winding V-shaped valleys with dendritic drainage
pattern. Steep slopes are littered with thin limestone slabs that remain
as shale erodes and washes away. The contrast with less-rugged upland
surfaces of adjacent areas is marked, except near major streams, where
the change is masked by dissection.
Hydrology
The Kope yields 100 to 500 gallons per day to drilled wells in valley
bottoms along large streams, but almost no water to drilled wells on
hillsides or ridgetops. It does yield water to small springs and seeps.
Water is hard in valley bottoms, and may contain salt or hydrogen sulfide.
Shale units have small, poorly connected openings that allow passage
of only small quantities of water, restricting yields to wells and springs
and preventing recharge to underlying rocks. The few thick limestone
beds may yield water to small springs. On ridgetops, shale impedes downward
percolation of water and supports water in the lower part of the soil
and in a weathered-rock zone just beneath the soil. High up on the sides
of many ridges is a zone of seeps and small springs. Where the Grant
Lake caps the ridges, the zone is generally near or at the contact with
the Kope Formation. Drilled wells on these ridges obtain a little water
at the contact between soil and bedrock, but rarely at greater depths;
if water is found at depth, it is mainly in small quantities and of
poor quality. Dug wells, with large wall areas, are better suited for
obtaining water from these bodies of water; however, many go dry in
late summer and fall.
The U.S. Geological Survey's Hydrologic Atlas Series, published cooperatively
with the Kentucky Geological Survey, provides hydrologic information
for the entire state. Atlases covering Campbell County are: HA-15,
HA-94,
HA-98.
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