POTENTIOMETRIC SURF ACE of the PRINCIPAL ARTESIAN AQUIFER ' 1N• GEORGIA-NOVEMBER, 1979

POTENTIOMETRIC SURF ACE of the PRINCIPAL ARTESIAN AQUIFER ' 1n• GEORGIA-NOVEMBER, 1979

by GAIL D. MITCHELL

Prepared as Georgia Department of Natural Resour~ Joe D. Tanner, Commissioner part of the Accelerated Ground-Water Program Environmental Protection Division J. Leonard Ledbetter, Director in cooperation with the Georgia Geologic Survey William H. McLemore, State Geologist Department of the Interior United States Geological Survey

82" 0 20 40 60 80 MILES I II I I I I I

HYDROLOGIC ATLAS 4

Atlanta

1980 The Department of Natural Resources is an equal opportunity employer and offers all persons the opportunity to compete and participate in each area of DNR employment regardless of race, color, religion, sex, national origin, age handicap, or other nonmerit factors. GEORGIA DEPARTMENT OF NAT URAL RESOUCES PREPARED IN COOPERATION WITH THE EN VIRON MENTAL PROTECT ION DIV ISION DE PARTMENT OF T HE INTERIOR HYDROLOGIC ATLAS 4 GEOLOG I C SURVEY GEOLOGICAL SURVEY .,. PL AT E I

POTENTIOMETRIC SURFACE OF THE PRI NC IPAL ARTESI AN AQUIFER

IN GEORGI A

An artesian aquifer, which is composed chiefly of limestone of Eocene to Oligocene age, underlies most of the southern half of Georgia . Th is aq uife r extends into Florida and parts of South Ca roli na and Alabama. In Georgia, it is referred to as the principal artesian aquifer and is the primary water su pply for municipalities, industries, and agricultu re in southern Georgia.

The principal artesian aquifer is at or near land surface from its northwest lim it to as much as 20 to 60 mi les southward of this line . It dips gently southeastward to a depth of more than 600 feet below land surface in Glynn County. It ranges in t hickness from 50 to 200 feet where it occurs near the surface to more than 500 feet thick along the coast.

The limestone is very caver nous and is confined above by clays and sa ndy days. Large quantities of water move through these caverns and smaller solution openings. Wells open to the aqu ifer commonly yie ld 1,000 to 5, 000 gal lons per minute .

REF ERENCES

Krause, R. E., and Gregg, D. 0., 1972, Water from the pr incipal artesian aquifer in coastal Georgia: Georgia Department of Natural Resources Hydrologic Atlas 1. ''\,

Matthews, S. E., Hester, W. G., and O'Byrne, M.P., 1980, Ground-water data for Georg ia , 1979: U. S. Geological Survey Open-File Report 80-501 , 94 p.

Stringfield, V. T., 1966, Artesian water in Tertiary limestone in the southeastern States: U.S. Geolog ical Su rvey Professional Paper 517, 226 p.

U.S. Geologica l Survey , 1978, Water-resources investigations in Georgia, 1978.

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E X PL ANAT I ON

-•o--POTENTI OMETR IC CON TOUR -Shows altitude at which water leve l wou ld have stood in ti gh tly cas ed we lls. Dashed whe re approx imate ly located. Contour i nter va l is 10 f ee t . Datum is Not iona l Ge odetic Ve r t ica I Datum of 1929.

DATA PO IN T To estimate t he water leve l above or below la nd surface i n a we l l, subt ract the a lti t ude of t he pot entiometr ic surface fro m the altitude of t he lond surface.

Whe re the a lt itude of t he po t entiometric surface is hi g he r than the a lt itude of t he la nd surface, wells penetrat i ng the aq ui fer w i ll f low .

.,. from U.S. Geologico! Sur~ey Cortoor ophy t>y Poul Grocof! e bose mops, 1963 POTENTIOMETRIC SURFACE OF THE PRINCIPAL ARTESIAN AQUIFER IN GEORGIA, NOVEMBER 1979 BY GAIL D. MITCHELL 1980