Groundwater Availability
 

Alluvium (Qa)

Topography
Alluvium forms narrow floodplains and underlies terraces. At least one well-developed terrace is present along each principal stream of the region.

Hydrology
Alluvium yields more than 100 gallons per day to most dug wells. Where sandy material is present and saturated thickness is great enough, more than 500 gallons per day would be yielded to screened drilled wells. Water is soft or moderately hard, and may contain large amounts of iron at depth.

Breathitt Group (Princess Formation, Four Corners Formation, Hyden Formation, Pikeville Formation) (Pbm, Pbl)

Topography
The Breathitt Group underlies the valleys and forms the hills of almost all the area north of Pine Mountain. South of Pine Mountain the rocks underlie the narrow valleys and form high, rugged hills. Tops of hills and ridges commonly are capped by sandstone. Shales form wide valleys and moderate or gentle slopes on hills.

Hydrology
The Breathitt yields more than 500 gallons per day to more than three-quarters of the wells drilled in valley bottoms. Throughout this area it yields more than 500 gallons per day to about three-quarters of the wells on hillsides and more than 100 gallons per day to nearly all wells on ridges. Sandstones yield water to most wells. Shales also yield water to many wells, and coal yields water to a few. Near-vertical joints and openings along bedding planes yield most of the water to wells. Waters are highly variable in chemical character.

Grundy, Alvy Creek Formations (contains Lee-type quartzose sandstones of the former Lee Formation) (PM1)

Topography
Thick, resistant sandstones form the high ridges of Pine, Cumberland, and Rocky Face Mountains.

Hydrology
These formations generally yield more than 500 gallons per day to about three-quarters of the wells drilled in valley bottoms. They yield more than 500 gallons per day to about half of the wells on hillsides and smaller quantities of water to wells on hilltops. Some wells flow. Sandstone is the principal aquifer, but shale yields water to some wells and coal to a few. Joints and openings along bedding planes, best developed in sandstones, supply most of the water to wells. Waters are generally soft or moderately hard and contain noticeable amounts of iron.

Pennington Group (PDpg)

Topography
The Pennington forms moderate slopes along the face of Pine Mountain. Hard beds of sandstones within this predominantly shale formation form small cliffs or ledges.

Hydrology
These rocks yield little or no water to wells.

Slade Formation (PDpg)

Topography
The Slade forms steep slopes and cliffs along the face of Pine Mountain.

Hydrology
The Slade yields more than 500 gallons per day to almost all the wells drilled in valley bottoms, and to many wells drilled on hills. The formation yields little water where overlain by Pennsylvanian rocks, but may yield more than 400 gallons per minute to wells at Pineville. Water is chiefly from solution cavities in limestone, but sandstone and shale yield water from fractures to a few wells. A few wells at shallow depth may contain salty water. The formation yields as much as 50 or 100 gallons per minute to springs in limestone.

Grainger Formation (PDpg)

Topography
The Grainger forms moderate slopes along the front of Pine Mountain.

Hydrology
The Grainger may yield more than 500 gallons per day to wells near the foot of Pine Mountain, but wells drilled into the formation throughout most of its outcrop area will yield little or no water.

Chattanooga Shale (MDc)

Topography
The Chattanooga forms moderate slopes along the base of Pine Mountain.

Hydrology
The shale yields little or no water to wells.

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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