USGS

Preliminary assessment of ground-water resources of Lauderdale County, Tennessee

U.S. Geological Survey, Water Resources Investigations Report 84-4104

by W.S. Parks, J.K. Carmichael and D.D. Graham

This report is available as a pdf below


Preface

The ground-water resource in Lauderdale County is in a rudimentary stage of development. Average withdrawal in 1982 was 3.1 million gallons per day by the main water-supply systems.

The principal shallow aquifers, from youngest to oldest, are the Mississippi alluvial deposits of Quaternary age and the Cockfield Formation, Memphis Sand, and Fort Pillow Sand of Tertiary age. The alluvial deposits, Cockfield, and Memphis Sand presently yield water for domestic, farm, industrial, irrigation, and public supplies. Existing wells range from less than 100 feet to as much as 800 feet in depth and pump from 5 to 1,500 gallons per minute. The deeper Fort Pillow Sand is, as yet, untapped.

Water levels fluctuate seasonally. High water-levels generally occur in the winter, spring, or early summer, and low water-levels occur in the fall or early winter. Water levels range from near land surface to as much as 275 feet below land surface--depending on the aquifer, location, and land-surface altitude.

Water from the Mississippi alluvial deposits, Cockfield Formation, and Memphis Sand is a calcium bicarbonate type and is generally of good quality. Undesirable parameters from the stand point of use are hardness and concentrations of dissolved iron and dissolved solids. Hardness is highest in the alluvial deposits (median value--from available analyses--354 milligrams per liter, as CaC03) and lowest in the Memphis Sand (median value--84 milligrams per liter, as CaC03). Dissolved iron concentrations are highest in the alluvial deposits (median value--11,200 micrograms per liter) and lowest in the Cockfield (median value--l,900 micrograms per liter). Dissolved solids concentrations are highest in the alluvial deposits (median value--402 milligrams per liter) and lowest in the Memphis Sand (median value--112 milligrams per liter). Although no water-quality data are available for the Fort Pillow Sand in Lauderdale County, this aquifer is known to have potential to yield a sodium bicarbonatetype water of somewhat better quality than is available from the shallower aquifers.

Values of transmissivity estimated from four single-well pumping tests are 17,700 and 24,100 cubic feet per day per foot for the Mississippi alluvial deposits, 1,500 cubic feet per day per foot for the Cockfield Formation, and 8,000 cubic feet per day per foot for the Memphis Sand. Because of partial penetration of the aquifers, these values of transmissivity may not be indicative of the total thickness of the individual aquifers.

Several north-northeast and west-northwest trending faults and their approximate locations are identified by correlation of the Cook Mountain on the geophysical logs of test holes and wells.

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