U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Prepared in cooperation with the

U.S. GEOLOGICAL SURVEY GROUND-WATER RESOURCES PROGRAM, ARKANSAS NATURAL RESOURCES COMMISSION, ARKANSAS GEOLOGICAL SURVEY, 

MEMPHIS LIGHT, GAS AND WATER, SHELBY COUNTY, TENNESSEE, AND THE CITY OF GERMANTOWN, TENNESSEE

SCIENTIFIC INVESTIGATIONS MAP 3014

Schrader, T.P., 2007, Sparta-Memphis aquifer—SHEET 1 of 1

Potentiometric surface in the Sparta-Memphis aquifer

 of the Mississippi Embayment, spring 2007

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WINN

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UNION

CLARKE

HINDS

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SABINE

DREW

YAZOO

CLAY

ASHLEY

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WAYNE

RANKIN

BOLIVAR

SMITH

COPIAH

ATTALA

SHELBY

BOSSIER

LONOKE

GRANT

ARKANSAS

DYER

CHOCTAW

LEAKE

HOLMES

GRANT

CHICOT

SCOTT

PANOLA

MILLER

CROSS

DALLAS

JASPER

CLARKE

OBION

TATE

HENRY

PRAIRIE

NATCHITOCHES

PHILLIPS

BIENVILLE

FAYETTE

MADISON

GIBSON

MISSISSIPPI

JEFFERSON

POINSETT

STODDARD

COLUMBIA

LA SALLE

OUACHITA

WARREN

BRADLEY

MONROE

MADISON

GREENE

GRAVES

CARROLL

LEFLORE

CLAIBORNE

LINCOLN

MARSHALL

NEWTON

CALHOUN

TUNICA

FRANKLIN

SIMPSON

CARROLL

DUNKLIN

WEBSTER

OUACHITA

TIPTON

JACKSON

MOREHOUSE

WEAKLEY

CRAIGHEAD

MADISON

HARDEMAN

COAHOMA

WASHINGTON

DE SOTO

SUNFLOWER

RICHLAND

LINCOLN

ST FRANCIS

NEW MADRID

HAYWOOD

WOODRUFF

CLEVELAND

CALDWELL

CRITTENDEN

BENTON

PEMISCOT

LAFAYETTE

SHARKEY

TALLAHATCHIE

QUITMAN

YALO

LAUDERDALE

LAKE

ISSAQUENA

MISSISSIPPI

HUMPHREYS

BALLARD

EAST CARROLL

HICKMAN

FULTON

CARLISLE

CROCKETT

WEST CARROLL

TIPTON

FULTON

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Mississippi

Alabama

Louisiana

Tennessee

Kentucky

Missouri

Arkansas

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91°

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36°

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80

MISSOURI

ARKANSAS

TENNESS

KENTU

ALABAM

MISSISSIPPI

LOUISIANA

Study Area

EE

CKY

A

CENOZOIC ERATHEM

TERTIARY QUATERNARY SYSTEM

Table 1. Hydrogeologic units and their correlation across the states within the Mississippi embayment. UPPER PALEOCENE EOCENE OLIGOCENE PLEISTOCENE HOLOCENE SERIES

LOUISIANA ARKANSAS MISSOURI KENTUCKY TENNESSEE MISSISSIPPI ALABAMA Hydrogeologic

Jackson Vicksburg

units

Wilcox Group Claiborne Group Group Group

Southern Northeastern

Alluvium, Mississippi River Alluvium and terrace, and Alluvium and Alluvium and loess deposits Valley alluvial terrace deposits loess terrace deposits aquifer deposits Undifferentiated

Vicksburg-Jackson Vicksburg Not present in study area confining unit Vicksburg Formation Formation

Jackson Group

Cockfield Upper Claiborne Gosport Sand Formation aquifer

Cook Middle Claiborne Mountain confining unit Formation

Sparta Sparta Sparta Lisbon

Sand Sand Sand Formation Middle 

CLaiborne 

Zilpha Clay Lower aquifer Cane Memphis Winona Sand Claiborne (Sparta- River Tallahatta Memphis Tallahatta confining Sand Formation Sand Tallahatta Memphis Formation Formation unit Formation aquifer)

Carrizo Meridian Sand Lower

Sand Member Claiborne

aquifer

Flour Island Wilcox Flour Hatchetigbee Upper Wilcox 

Formation Formation Island Formation aquifer

Bashi Formation

Dolet Tuscahoma Sand Undifferentiated

Hills Bells Landing Fort Pillow No Wilcox Formation Fort Pillow Marl Member Middle Wilcox Sand deposits Sand Nanafalia Formation aquifer identified as Grampian Hills Member being of Gravel Creek Paleocene age Sand Member

Undifferentiated Old Breast- Old Breast- Gravel Creek Naborton Formation works works Sand Member Formation Formation

Midway confining Midway Group unit

Modified from Hosman and Weiss, 1991

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100

Explanation

Approximate outcrop of the Sparta Sand and the Memphis Sand 

(Modified from Bicker, 1969; Hosman, 1982; Hosman and others,

1968; Miller and Fullerton, 1966)

Cones of depression in the potentiometric surface

Well completed in Sparta-Memphis aquifer 

Potentiometric contour—Shows altitude at which water level 

would have stood in tightly cased wells. Dashed where approximately 

located. Hachures indicate depression. Contour interval 20 feet.

Datum is NGVD of 1929

Approximate direction of ground-water flow

Introduction

The most widely used aquifer for industry and public supply in the Mississippi 

embayment in Arkansas, Louisiana, Mississippi, and Tennessee is the Sparta-Memphis 

aquifer. Decades of pumping from the Sparta-Memphis aquifer have affected 

ground-water levels throughout the Mississippi embayment. Regional assessments of 

water-level data from the aquifer are important to document regional water-level 

conditions and to develop a broad view of the effects of ground-water development and 

management on the sustainability and availability of the region's water supply. This 

information is useful to identify areas of water-level declines, identify cumulative areal 

declines that may cross State boundaries, evaluate the effectiveness of ground-water 

management strategies practiced in different States, and identify areas with substantial 

data gaps that may preclude effective management of ground-water resources.

A ground-water flow model of the northern Mississippi embayment is being 

developed by the Mississippi Embayment Regional Aquifer Study (MERAS) to aid in 

answering questions about ground-water availability and sustainability. The MERAS 

study area covers parts of eight states including Alabama, Arkansas, Illinois, Kentucky, 

Louisiana, Mississippi, Missouri, and Tennessee and covers approximately 70,000 square 

miles. The U.S. Geological Survey (USGS) and the Mississippi Department of 

Environmental Quality Office of Land and Water Resources measured water levels in 

wells completed in the Sparta-Memphis aquifer in the spring of 2007 to assist in the 

MERAS model calibration and to document regional water-level conditions. 

Measurements by the USGS and the Mississippi Department of Environmental Quality 

Office of Land and Water Resources were done in cooperation with the Arkansas Natural 

Resources Commission; the Arkansas Geological Survey; Memphis Light, Gas and 

Water; Shelby County, Tennessee; and the city of Germantown, Tennessee. 

In 2005, total water use from the Sparta-Memphis aquifer in the Mississippi 

embayment was about 540 million gallons per day (Mgal/d). Water use from the 

Sparta-Memphis aquifer was about 170 Mgal/d in Arkansas, about 68 Mgal/d in 

Louisiana, about 97 Mgal/d in Mississippi, and about 205 Mgal/d in Tennessee (Terrance 

W. Holland, U.S. Geological Survey, written commun., 2007). 

The author acknowledges, with great appreciation, the efforts of the personnel in the 

U.S. Geological Survey Water Science Centers of Arkansas, Kentucky, Louisiana, 

Mississippi, Missouri, and Tennessee, and the Mississippi Department of Environmental 

Quality Office of Land and Water Resources that participated in the planning, water-level 

measurement, data evaluation, and review of the potentiometric-surface map. Without the 

contribution of data and the technical assistance of their staffs, this report would not have 

been completed. 

Description of Aquifer

In the southern part of the Mississippi embayment (south of about 35 degrees north 

latitude), the Sparta Sand of Claiborne Group (herein referred to as the Sparta Sand) is 

composed of a sequence of alternating sand and clay beds between the massive clays of 

the confining units of the overlying Cook Mountain Formation of Claiborne Group and 

the underlying Tallahatta Formation of Claiborne Group in Alabama, Cane River 

Formation of Claiborne Group in Arkansas and Louisiana, and the Zilpha Clay of 

Claiborne Group in Mississippi (table 1). In Alabama, the Lisbon Formation of Claiborne 

Group is equivalent to the Sparta Sand. In the northern Mississippi embayment (north of 

about 35 degrees north latitude), the Memphis Sand of Claiborne Group (herein referred 

to as the Memphis Sand) (Sparta Sand equivalent) is between the confining units of the 

overlying Cook Mountain Formation of Claiborne Group and the underlying Flour Island 

Formation of Wilcox Group in Arkansas, Missouri, and Tennessee and the Tallahatta 

Formation of Claiborne Group in Kentucky. At about 35 degrees north latitude there is a 

transition zone where the Cane River Formation of Claiborne Group in Arkansas and the 

Zilpha Clay of Claiborne Group in Mississippi have a facies change or pinch out. The 

sequence of the Sparta Sand, Cane River Formation or Zilpha Clay, and the Carrizo Sand 

of Claiborne Group merges into the Memphis Sand at approximately 35 degrees north 

latitude. 

Herein, the sand layers within the Sparta Sand and Memphis Sand that comprise the 

Sparta aquifer and the Memphis aquifer will be referred to as the Sparta-Memphis 

aquifer. Water levels in the Sparta aquifer generally correlate with those in the Memphis 

aquifer; therefore, the water-bearing formations are considered to be one hydrologic unit 

(Stanton, 1997). Except for the outcrop area, the Sparta-Memphis aquifer is a confined 

aquifer that lies several hundred feet beneath the land surface. The average thickness of 

the aquifer is 450 feet with a maximum thickness of about 1,100 feet near the axis of the 

Mississippi embayment, which is roughly parallel to the Mississippi River at the southern 

limit of the study area. A more detailed description of the Sparta-Memphis aquifer is 

given in Davis and others (1973), Hosman and others (1968), Hosman (1996), Newcome 

(1976), Parks and Carmichael (1990b), Payne (1968), Petersen and others (1985), Ryals 

(1980), and Snider and others (1972). 

Potentiometric Surface

The potentiometric-surface map was constructed using 748 water-level 

measurements from wells completed in the Sparta-Memphis aquifer in the spring of 

2007. Water-level data are available in the USGS National Water Information System at 

http://waterdata.usgs.gov/nwis. Water levels were measured using calibrated electric or 

steel tapes to an accuracy of 0.01 feet. The map is based upon water-level data collected 

in 309 wells in Arkansas, 7 wells in Kentucky, 116 wells in Louisiana, 150 wells in 

Mississippi, 6 wells in Missouri, and 160 wells in Tennessee in the Sparta-Memphis 

aquifer. The potentiometric-surface map of the Sparta-Memphis aquifer shows the 

altitude at which water would have stood in tightly cased wells completed in the aquifer. 

The potentiometric surface is mapped by determining the altitude of the water levels 

measured in the wells and is represented on the map by contours that connect points of 

equal water-level altitude. Hydrologic principles, water-use data, and historical 

information are interpreted with the water-level data to delineate the 

potentiometric-surface contours. 

The general direction of ground-water flow in an aquifer is perpendicular to the 

contours in the direction of decreasing hydraulic gradient. The natural direction of 

ground-water flow in the Sparta-Memphis aquifer is toward the axis of the Mississippi 

embayment (Hosman and others, 1968). The natural direction of flow has been altered in 

areas by large ground-water withdrawals. 

The highest water-level altitude measured was 513 feet above the National Geodetic 

Vertical Datum of 1929 (sometimes referred to as sea level) in Madison County, 

Tennessee. The lowest water level measured was 225 feet below the National Geodetic 

Vertical Datum of 1929 in Ouachita Parish, Louisiana. 

Cones of depression in the potentiometric surface usually are caused by moderate to 

large ground-water withdrawals. The cones of depression alter the flow of ground water 

towards the center of pumping. When a well is pumped, the water level in and around the 

well declines, creating a slope or gradient in the potentiometric surface. The gradient 

alters the natural direction of flow of water in the aquifer towards points of lower water 

level. When pumping is reduced or stops, the water level recovers to a new equilibrium. 

In an area with multiple pumping wells, the area of the declining water level expands to 

form a depression in the ground-water surface composed of multiple cones of depression.

Twenty cones of depressions (generally represented by a series of closed contours) 

are shown in the potentiometric surface of the Sparta-Memphis aquifer and are shaded in 

gray on the map. Five locations centered at cities with large withdrawals for public 

supply and industrial uses have large cones of depression with greater than 40 feet of 

decline. The large cones of depression are in Jefferson and Union Counties, Arkansas; 

Ouachita Parish, Louisiana; Rankin County, Mississippi; and Shelby County, Tennessee. 

The cones of depression in Jefferson and Union Counties, Arkansas, are greater than 100 

feet and 80 feet deep, respectively. The cone of depression in Ouachita Parish, Louisiana, 

is greater than 160 feet deep. The cone of depression in Rankin County, Mississippi, is 

greater than 40 feet deep. The cone of depression in Shelby County, Tennessee, is greater 

than 60 feet deep. The remaining 15 depressions are mostly centered near small or 

intermediate cities where withdrawals have formed a cone of depression less than 40 feet 

deep. The large withdrawals that caused the cones of depression also alter the natural 

ground-water flow direction towards the cones of depression. 

Selected References

Bicker, A.R., comp., 1969, Geologic map of Mississippi: [Jackson], Mississippi Geological 

Survey, scale 1:500,000.

Davis, R.W., Lambert, T.W., and Hansen, A.J., Jr., 1973, Subsurface geology and ground-water 

resources of the Jackson Purchase region, Kentucky: U.S. Geological Survey Water-Supply 

Paper 1987, 66 p.

Hosman, R.L. 1982, Outcropping Tertiary units in southern Arkansas: U.S. Geological Survey 

Miscellaneous Investigations Series I-1405, 1 sheet.

Hosman, R.L., 1996, Regional stratigraphy and subsurface geology of Cenozoic deposits, Gulf 

Coastal Plain, south-central United States: U.S. Geological Survey Professional Paper 1416-G, 

35 p. 

Hosman, R.L., Long, A.T., Lambert, T.W., and others, 1968, Tertiary aquifers in the Mississippi 

Embayment: U.S. Geological Survey Professional Paper 448-D, 29 p.

Hosman, R.L., and Weiss, J.S., 1991, Geohydrologic units of the Mississippi Embayment and 

Texas Coastal Uplands aquifer systems, South-Central United States: U.S. Geological Survey 

Professional Paper 1416-B, 19 p.

Luckey, R.R., 1985, Water resources of the Southeast Lowlands, Missouri: U.S. Geological 

Survey Water-Resources Investigation Report 84–4277, 77 p.

Miller, R.A., Harderman, W.D., Fullerton, D.S., comps., 1966, Geologic map of Tennessee, west 

sheet: [Nashville], Tennessee Department of Conservation, Division of Geology, scale 

1:250,000.

Newcome, Roy, Jr., 1976, The Sparta aquifer system in Mississippi: U.S. Geological Survey 

Water-Resources Investigation Report 76–7, 3 sheets.

Parks, W.S., and Carmichael, J.K., 1990a, Altitude of potentiometric surface, fall 1985 and 

historic water-level changes in the Memphis aquifer in western Tennessee: U.S. Geological 

Survey Water-Resources Investigation Report 88–4180, 8 p. 

Parks, W.S., and Carmichael, J.K., 1990b, Geology and ground-water resources of the Memphis 

Sand in western Tennessee: U.S. Geological Survey Water-Resources Investigations Report 

88–4182, 30 p.

Payne, J.N., 1968, Hydrologic significance of the lithofacies of the Sparta Sand in Arkansas, 

Louisiana, Mississippi, and Texas: U.S. Geological Survey Professional Paper 569-A, 17 p.

Petersen, J.C., Broom, M.E., and Bush, W.V., 1985, Geohydrologic units of the Gulf Coastal 

Plain in Arkansas: U.S. Geological Survey Water-Resources Investigations Report 85–4116, 

20 p.

Ryals, G.N., 1980, Potentiometric surface maps of the Sparta Sand, northern Louisiana and 

southern Arkansas, 1900, 1965, 1975, and 1980: U.S. Geological Survey Open-file Report 

80–1180, 1 sheet.

Schrader, T.P., and Jones, J.S., 2007, Status of water levels and selected water-quality conditions 

in the Sparta-Memphis aquifer in Arkansas and the status of water levels in the Sparta aquifer 

in Louisiana, spring 2005: U.S. Geological Survey Scientific Investigations Report 2007–5029, 

66 p. 

Snider, J.L., Calandro, A.J., and Shampine, W.J., 1972, Water resources of Union Parish, 

Louisiana: Department of Conservation, Louisiana Geological Survey, and Louisiana 

Department of Public Works Water Resources Bulletin No. 17, 68 p.

Stanton, G.P., 1997, Potentiometric surface and specific conductance of the Sparta and Memphis 

aquifers in eastern and south-central Arkansas, 1995: U.S. Geological Survey Water-Resources 

Investigations Report 97–4119, 16 p.

MISSISSIPPI 

RIVER

MISSISSIPPI 

RIVER

POTENTIOMETRIC SURFACE IN THE SPARTA-MEMPHIS AQUIFER OF THE MISSISSIPPI EMBAYMENT, SPRING 2007

By

T.P. Schrader

2008

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For additional information, contact:

Director, U.S. Geological Survey

Arkansas Water Science Center

401 Hardin Road

Little Rock, AR 72211 

E-mail: dc_ar@usgs.gov

Fax: (501) 228-3601

Telephone: (501) 228-3600

Home Page: http://ar.water.usgs.gov

Copies of this report can be purchased from:

U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

E-mail: infoservices@usgs.gov

Fax: (303) 202-4188

Telephone: 1-888-ASK-USGS

Home Page: http://www.usgs.gov

Publishing support provided by:

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