Preliminary delineation and description of the regional aquifers of Tennessee– The Cretaceous aquifer system of west-Tennessee

The Cretaceous aquifer system in western Tennessee is composed of sand, gravel, and clay. The aquifer system is under confined conditions except in the outcrop area. Ground water is recharged by precipitation on the outcrop area and through some overlying permeable deposits. The hydraulic gradient in the confined aquifers is about 1 foot per mile generally toward the west. The Cretaceous aquifer system unconformably overlies the consolidated Paleozoic formations and is overlain and confined by the Porters Creek Clay.

The Cretaceous aquifer system is used as a source of water supply primarily in the outcrop area. West of the outcrop of this aquifer system, ground water can be obtained at shallower depths and with better water quality. The water of the Cretaceous aquifers generally have very good quality in the outcrop area. The dissolved solids increase down gradient to more than 1,000 milligrams per liter in parts of Shelby County. High iron concentrations are present in some areas.