Potentiometric Surfaces in the Cockfield and Wilcox 

Aquifers of Southern and Northeastern Arkansas, 

2003

MISSISSIPPI

ALLUVIAL

PLAIN

OZARK PLATEAUS

ARKANSAS VALLEY

OUACHITA MOUNTAINS

WEST GULF

COASTAL PLAIN

MISSISSIPPI RIVER

Tennessee

Missouri

Oklahoma

Texas

Louisiana

Mississippi

34o

36o

35o

94o

93o 92o 91o

Crowleys Ridge

0 20 40 Miles

0 20 40 Kilometers

Prepared in cooperation with the

ARKANSAS SOIL AND WATER CONSERVATION COMMISSION

and the ARKANSAS GEOLOGICAL COMMISSION

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2004-5169
Potentiometric Surfaces in the Cockfield 

and Wilcox Aquifers of Southern and 

Northeastern Arkansas, 2003

By Daniel S. Yeatts

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

ARKANSAS SOIL AND WATER CONSERVATION COMMISSION

and the ARKANSAS GEOLOGICAL COMMISSION

Scientific Investigations Report 2004-5169
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

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endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.
Contents

 iii

Abstract...................................................................................................................................................................................................... 1

Introduction ............................................................................................................................................................................................... 1

Methods ..................................................................................................................................................................................................... 2

Cockfield Formation ................................................................................................................................................................................. 3

Hydrogeologic Setting.................................................................................................................................................................. 3

Potentiometric Surface................................................................................................................................................................ 3

Water-Level Trends....................................................................................................................................................................... 7

Wilcox Group........................................................................................................................................................................................... 13

Hydrogeologic Setting................................................................................................................................................................ 13

Potentiometric Surface.............................................................................................................................................................. 13

Water-Level Trends..................................................................................................................................................................... 13

Summary .................................................................................................................................................................................................. 23

References .............................................................................................................................................................................................. 23

Figures

1. Map showing location of study area ........................................................................................................................................ 2

2. Diagram showing well-numbering system............................................................................................................................... 3

3. Map showing potentiometric surface of the Cockfield aquifer in southeastern Arkansas. 2003 .................................. 4

4. Hydrographs showing water-level altitudes for selected wells completed in the Cockfield aquifer in

southeastern Arkansas ............................................................................................................................................................... 8

5. Map showing potentiometric surface of the Wilcox aquifer in southern Arkansas, 2003 ............................................ 14

6. Map showing potentiometric surface of the Wilcox aquifer in northeastern Arkansas, 2003 ..................................... 15

7. Hydrographs showing water-level altitudes for selected wells completed in the Wilcox aquifer in northeastern

Arkansas...................................................................................................................................................................................... 19

Tables

1. Information pertaining to measured wells completed in the Cockfield aquifer in southeastern Arkansas, 2003 ....... 5

2. Water-level trends for wells in the Cockfield aquifer that have water levels for the 20-year period from

1983-2003..................................................................................................................................................................................... 12

3. Information pertaining to measured wells completed in the Wilcox aquifer in southern Arkansas, 2003 ................. 16

4. Information pertaining to measured wells completed in the Wilcox aquifer in northeastern Arkansas, 2003.......... 17

5. Water-level trends for wells in the Wilcox aquifer that have water levels for the 20-year period from 1983-2003 .. 22
Potentiometric Surfaces in the Cockfield and Wilcox 

Aquifers of Southern and Northeastern Arkansas, 2003

By Daniel S. Yeatts

Abstract

This report presents the results of water-level measurements made at wells in the Cockfield Formation and Wilcox 

Group of southern and northeastern Arkansas during 2003, and 

the water levels are displayed in potentiometric-surface maps 

and hydrographs. During March and April 2003, the water level 

was measured at 55 wells completed in the Cockfield aquifer, 

13 wells completed in the Wilcox aquifer of southern Arkansas, 

and 43 wells completed in the Wilcox aquifer of northeastern 

Arkansas. 

The Cockfield Formation generally consists of discontinuous sand units interbedded with silt, clay, and lignite in southeastern Arkansas. Sand beds near the base of the Cockfield Formation constitute most of the Cockfield aquifer. Withdrawals 

from the Cockfield aquifer in the study area during 2000 totaled 

about 9 million gallons per day. The potentiometric surface of 

the Cockfield aquifer constructed from the 2003 water levels 

shows that regional direction of ground-water flow generally is 

towards the east and southeast, away from the outcrop, except 

in areas of intense ground-water withdrawals. Some local 

ground-water flow in the outcrop area is toward rivers that have 

eroded into the Cockfield Formation and deposited alluvium in 

south Bradley and Calhoun Counties (Ouachita River), and in 

north Dallas County (Saline River). An evaluation of 20 wells 

with water-level data from 1983 to 2003 shows that water levels 

in 15 wells have declined at a rate of -0.04 to -0.97 feet per year, 

and water levels in 5 wells have risen at a rate of 0.07 to 0.32 

feet per year. An evaluation of the same 20 wells from 2000 to 

2003 shows that water levels have declined in only 8 wells, and 

water levels have risen in 12 wells.

The Wilcox Group is distributed throughout most of southern and eastern Arkansas. There are two study areas in southern 

and northeastern Arkansas.

The Wilcox Group of the southern study area consists of 

interbedded clay, sandy clay, sand, and lignite. Thin discontinuous sand units constitute the Wilcox aquifer in the southern 

study area. Withdrawals from the aquifer in the southern study 

area were about 1 million gallons per day during 2000. The 

potentiometric surface of the Wilcox aquifer in the southern 

study area shows that regional ground-water flow generally is 

south and east, except in Clark County where flow is towards 

the Ouachita River.

The Wilcox Group in the northeastern study area consists 

of thin interbedded lignitic sand and clays. A sand bed of about 

200 feet thick in the middle to lower part of the Wilcox Group 

constitutes the major producing unit of the Wilcox aquifer in the 

northeastern study area. Withdrawals from the aquifer in the 

northeastern study area were about 23 million gallons per day 

during 2000. The potentiometric surface of the Wilcox aquifer 

in the northeastern study area shows that ground-water flow 

generally is south and east, except where ground-water withdrawals may have altered the natural direction of flow near the 

centers of pumping at Paragould and West Memphis. An evaluation of 27 wells with water-level data from 1983 to 2003 in 

the northeastern study area shows that water levels in all 27 

wells have been declining at a rate of -0.17 to -1.73 feet per 

year. An evaluation of the same 27 wells from 2000 to 2003 

shows that water levels in 18 wells have risen and in 9 wells 

have declined. 

Introduction

The Cockfield Formation of Claiborne Group (hereafter 

referred to as Cockfield Formation) and the Wilcox Group contain aquifers that provide sources of ground water in southern 

and northeastern Arkansas. During the year 2000, about 36 million gallons per day (Mgal/d) of water was withdrawn from 

these aquifers in Arkansas, about 3Mgal/d of which is from outside the study areas (T.W. Holland, U.S. Geological Survey, 

written commun., 2003). Major withdrawals from the aquifers 

were for industrial and public water supplies, with lesser but 

locally important withdrawals for domestic and livestock uses.

A study was conducted by the U.S. Geological Survey in 

cooperation with the Arkansas Soil and Water Conservation 

Commission and the Arkansas Geological Commission to 

determine the water level associated with the aquifers in the 

Cockfield Formation and the Wilcox Group in southern and 

northeastern Arkansas. This report presents the results of the 

water-level measurements made during 2003 and displays the 

water levels in potentiometric-surface maps and in hydrographs 

for wells with data from 1983 to 2003.
MISSISSIPPI

ALLUVIAL

PLAIN

OZARK PLATEAUS

ARKANSAS VALLEY

OUACHITA MOUNTAINS

WEST GULF

COASTAL PLAIN

MISSISSIPPI RIVER

Tennessee

Missouri

Oklahoma

Texas

Louisiana

Mississippi

34o

36o

35o

94o

93o 92o 91o

CROWLEYS RIDGE

EXPLANATION

Study area of

Cockfield aquifer

in southeastern

Arkansas

Study area of

Wilcox aquifer

in southern

Arkansas

Study area of

Wilcox aquifer

in northeastern

Arkansas

0 20 40 Miles

0 20 40 Kilometers

Clay

Greene

Mississippi Craighead

Poinsett

Cross Crittenden

St. Francis

Lee

Hot Spring

Clark Dallas

Ouachita Nevada Hempstead

Grant

Columbia Union Ashley

Chicot

Bradley

Drew

Desha

Arkansas

Calhoun

Cleveland

Jefferson

Lincoln

2 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 1. Location of study areas.

The study areas of the Cockfield and Wilcox aquifers (fig. 

1) include much of the West Gulf Coastal Plain and the Mississippi Alluvial Plain in Arkansas. The study area boundary of the 

Cockfield aquifer in southeastern Arkansas is bounded on the 

east by the Mississippi River and on the south by the Louisiana 

State line. The western and northern boundaries are defined by 

the western and northern extent of the outcrop and subcrop 

(Hosman, 1982) of the Cockfield Formation and by locations of 

observation wells. The study area boundary of the Wilcox aquifer in southern Arkansas is defined by the outcrop of the Wilcox 

Group and the locations of observation wells in Clark, Hempstead, Hot Spring, Nevada, and Ouachita Counties. The study 

area of the Wilcox aquifer in northeastern Arkansas is bounded 

on the north by the Missouri State line and on the east by the 

Mississippi River. The western and southern boundaries of the 

study area are defined by the extent of the outcrop at or near 

Crowleys Ridge, and by the location of observation wells that 

penetrate the Wilcox aquifer.

A previous report (Schrader and Joseph, 2000) describing 

the potentiometric surfaces of the Cockfield and Wilcox aquifers showed data measured during January through April, 2000. 

For that report, 54 and 56 wells completed in the Cockfield and 

Wilcox aquifers, respectively, were measured for water levels.

Methods

The well-numbering system used in this report is based 

upon the location of the wells according to the Public Land Survey System used in Arkansas. The component parts of a well 

number are the township number, the range number, the section 

number, three letters which indicate, respectively, the quarter 

section, the quarter-quarter section, and the quarter-quarterquarter section in which the well is located, and a sequence 

number. The letters are assigned counterclockwise, beginning 

with “A” in the northeast quarter or quarter-quarter or quarterquarter-quarter section in which the well is located. For example, well 01S03W04BBD16 (fig. 2) is located in Township 1 

South, Range 3 West, and in the southeast quarter of the northwest quarter of the northwest quarter of section 4. This well is 

the 16th well in this quarter-quarter-quarter section of section 4 

from which data were collected.

The horizontal coordinate information of wells was determined using a global positioning system (GPS) referenced to 

the North American Datum of 1983 (NAD 83), with accuracy 

to about one-tenth of a second of latitude and longitude (approximately 10-20 feet). The vertical coordinate information was 

determined with accuracy to about 5 feet from topographic 

maps referenced to the National Geodetic Vertical Datum of 

1929 (NGVD of 1929)1.

1

In this report, NGVD of 1929 refers to the National 

Geodetic Vertical Datum of 1929—a geodetic datum 

derived from a general adjustment of the first-order 

level nets of the United States and Canada, formerly 

called Sea Level Datum of 1929.
A

B

A

C

D

C

D

B

A

B

A

C

D

C

D

C

D

B

A

B

C A DB

6

3

2

1

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

R-3-W

T-1-S

SECTION 4

WELL 01S03W04BBD16

4S 3S 2S 1S

5W 4W 3W 2W 1W 1E 2E 3E 4E

PRINCIPAL MERIDIAN

BASELINE

WEST

RANGES

EAST SOUTH

TOWNSHIPS

NORTH

Cockfield Formation 3

Figure 2. Well-numbering system.

Water levels were measured by U.S. Geological Survey 

personnel at public water supply, industrial, commercial, 

domestic, and observation wells open to the Cockfield or Wilcox aquifers. Measurements were made using steel or electric 

tapes graduated to hundredths of a foot. The steel and electric 

tapes were calibrated during January 2003.

Cockfield Formation

Hydrogeologic Setting

The Cockfield Formation is Eocene age and generally consists of discontinuous fine- to medium-grained sand units interbedded with silt, clay, and lignite in southeastern Arkansas. 

Most of the sand beds constitute the Cockfield aquifer media, 

and are found near the base of the Cockfield Formation. The 

Cockfield Formation generally ranges from 100 to 400 feet (ft) 

thick near the outcrop area and thickens downdip of the outcrop 

area reaching 625 ft thick in northeastern Chicot County (Onellion and Criner, 1955). Total sand thickness in the Cockfield 

Formation generally ranges from 20 to 150 ft. The Cockfield 

Formation is underlain throughout the study area by calcareous 

and sandy marl, limestone, and carbonaceous clay of the Cook 

Mountain Formation. The Cockfield Formation is overlain by 

silty clays of the Jackson Group throughout much of southeastern Arkansas. Sand beds at the base of the overlying Jackson 

Group in parts of southeastern Arkansas may be in hydraulic 

connection with the Cockfield aquifer (Ackerman, 1987).

The Cockfield Formation outcrops in the northwestern 

extent of the study area and dips southeastward. In the subcrop 

area, the Cockfield Formation is overlain by terrace deposits 

and alluvium of Quaternary age. The terrace deposits may attain 

a thickness of 40 ft, and as much as 60 ft of alluvium overlies 

the Cockfield Formation in some of the larger river valleys. The 

Cockfield Formation dips southeastward from the outcrop and 

subcrop areas and is confined above by the Jackson Group. In 

the confined part of the aquifer, the potentiometric surface can 

be near, or above, land surface.

Most recharge to the Cockfield aquifer occurs by infiltration of rainfall on the upland outcrop areas and by inflow from 

the overlying alluvium; most discharge is to rivers in outcrop 

areas, to vertically adjacent units where the Cockfield aquifer is 

confined, and to wells (Ackerman, 1987). Well depths are shallow and yields of most wells in the outcrop areas are small, less 

than 30 gallons per minute (gal/min), but in other areas downdip 

of the outcrop, wells screened the full thickness of the aquifer 

often yield 100 to 500 gal/min (Westerfield, 1994).

Withdrawals from the Cockfield aquifer in the study area 

during 2000 totaled about 9 Mgal/d (T.W. Holland, U.S. Geological Survey, written commun., 2003). Adjacent to Arkansas, 

the State of Mississippi pumped about 27 Mgal/d from the 

Cockfield aquifer in 1999 (D.E. Burt, U.S. Geological Survey, 

written commun., 2003). Immediately across the Arkansas/Mississippi State line, the city of Greenville, Mississippi pumped 

about 11 Mgal/d from the Cockfield aquifer in 1999 (D.E. Burt, 

U.S. Geological Survey, written commun., 2003), or about as 

much as all of Arkansas pumped from the Cockfield aquifer in 

2000. The large amount of withdrawal from Greenville probably contributes to lower water levels in Arkansas (Ackerman, 

1987; Joseph, 1998; Schrader and Joseph, 2000). Most wells 

completed in the Cockfield aquifer study area provide small 

volumes of water for domestic and livestock use. In some locations, the Cockfield aquifer yields volumes large enough to supply industrial and public supply systems.

Potentiometric Surface

The potentiometric-surface map shows the altitude of the 

water surface in tightly cased wells screened in the Cockfield 

aquifer (fig. 3). The map is based upon water-level data collected at 55 wells in the Cockfield aquifer during March and 

April 2003, in southeastern Arkansas (table 1). The potentiometric surface was constructed by determining the water-level 

altitude at wells, and constructing contour lines along points of 

equal water-level value. The direction of ground-water flow is 

perpendicular to the contours in the direction of decreasing 

water level. 
Ouachita

River

Saline

River

A

B

C

D

E

F

G

H

Greenville,

Mississippi

280

80

Crossett

80

120

160

140

180

200

220

240

260

280

300

320

340

220

260

140

200

240

160

180

200

180

UNION

DREW

ASHLEY

DESHA

ARKANSAS

GRANT

CHICOT

DALLAS

JEFFERSON

COLUMBIA

OUACHITA

BRADLEY

LINCOLN

CALHOUN

CLEVELAND

100

220

260

100

120

100

70

83

74

97

82

68 84

69 62

84 80

84 83

92

89

98

99

86

88

92

70 90

88

75

239 206

262 130

155

230

160

203

176

190

162

107

264

255 295

163

235

260

196

213

178

134

125

230

115

110 133

115

101

353

266

34o

33 30' o

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

EXPLANATION

WELL COMPLETED IN THE COCKFIELD AQUIFER--

Number is water-level altitude. Letter, where present,

corresponds to hydrograph in figure 4.

70

G

POTENTIOMETRIC CONTOUR-- Shows altitude at

which water level would have stood in tightly cased

wells. Hachures indicate depression. Contour

interval 20 feet. Datum is National Geodetic Vertical

Datum of 1929

180

OUTCROP OF COCKFIELD FORMATION

(Modified from Hosman, 1988)

91 30' o

92 30' o

92o

4 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 3. Potentiometric surface of the Cockfield aquifer in southeastern Arkansas, 2003.
 Cockfield Formation 5

Table 1. Information pertaining to measured wells completed in the Cockfield aquifer in southeastern Arkansas, 2003.

[In this report, the well latitudes and longitudes were measured using a global positioning system referenced to the North American Datum of 1983. ddmmss,

degrees, minutes, seconds; NGVD of 1929 refers to the National Geodetic Vertical Datum of 1929; --, no data]

Latitude

(ddmmss)

Longitude

(ddmmss)

Local well 

number

Well 

depth

(feet)

Land-surface

datum

altitude

(feet above

NGVD of 1929)

Water-level

altitude

(feet above

NGVD of 1929)

Depth to

water

(feet below

landsurface

datum)

Date of

measurement

Arkansas County

340138 911405 08S02W04ACA1 453 165 75 89.53 4/08/2003

Ashley County

330336 913425 19S05W12CAC1 320 115 88 27.24 3/20/2003

330710 913247 18S04W19DAA2 356 116 90 25.75 3/20/2003

331038 915627 18S08W04BBC1 314 149 70 78.95 3/20/2003

331406 913033 17S04W10CBA1 360 125 92 32.96 3/20/2003

331417 913030 17S04W10BCD2 340 125 88 37.04 3/20/2003

331442 914510 17S06W07ADA1 426 174 101 73.05 3/20/2003

332144 912932 15S04W26CBC1 409 128 86 41.99 3/20/2003

Bradley County

331951 920619 16S10W11DCB1 152 152 99 53.20 3/19/2003

332027 921223 16S11W11ACA1 140 141 115 26.45 3/19/2003

332536 921858 15S12W11CAB1 225 155 133 22.19 3/19/2003

332650 921233 14S11W35DAC1 345 174 110 63.94 3/19/2003

332656 921251 14S11W35CAB1 320 190 115 74.73 3/19/2003

332658 921025 14S10W31DBA1 349 193 98 94.86 3/19/2003

333139 920522 14S10W01BAD1 540 231 89 141.96 3/19/2003

333815 921046 12S10W30CAC1 58 240 230 10.49 3/19/2003

Calhoun County

332815 922729 14S13W29DAC1 -- 139 125 13.53 3/14/2003

332829 922722 14S13W29ADA1 81 160 134 25.72 3/14/2003

333045 922451 14S13W11CAC1 105 205 178 27.11 4/30/2003

333517 922520 13S13W15DBA1 122 232 213 19.11 3/14/2003

333555 922638 13S13W09CBD1 147 232 196 36.47 3/14/2003

334560 922534 11S13W15BBC1 70 310 260 50.33 3/14/2003

Chicot County

330640 911541 18S02W25ABB3 332 135 92 43.42 3/24/2003

330652 911547 18S02W24CDB1 364 129 83 45.99 3/24/2003

330731 912319 18S03W14CCC1 320 98 84 13.66 3/24/2003

332027 911857 16S02W04BAC1 330 125 80 45.12 3/21/2003

332314 912438 15S03W21ABA1 400 122 84 38.20 3/21/2003

333106 912602 14S03W05BBA1 510 139 62 76.91 3/21/2003

333247 912301 13S03W26BBB1 422 139 69 70.10 3/21/2003
6 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Cleveland County

334449 921258 11S11W23BBD1 148 275 235 40.10 3/26/2003

335534 920942 09S10W17CDD1 361 270 266 3.57 3/26/2003

335902 922444 08S13W34BDA1 181 248 163 85.46 4/03/2003

Columbia County

330233 930958 19S20W34ADC1 40 313 295 17.71 3/18/2003

330247 931513 19S21W35ADC1 30 256 255 0.91 3/18/2003

330520 931857 19S21W17CBB1 55 306 264 42.47 3/18/2003

331313 930914 17S20W35BBD1 -- 361 353 7.57 3/18/2003

Desha County

333504 911921 13S02W08CAA1 515 147 84 62.62 3/25/2003

333628 911245 12S01W32DCA1 495 136 68 67.78 3/25/2003

333747 912611 12S03W30ADC1 280 153 82 70.89 3/25/2003

Drew County

332754 914744 14S07W26BAB1 440 230 107 122.87 3/26/2003

332846 914339 14S06W21BDC1 -- 216 97 118.77 3/26/2003

333750 915551 12S08W33AAB1 543 173 74 99.26 3/26/2003

334216 913438 11S05W35DDB1 500 180 83 96.66 3/26/2003

Lincoln County

335204 913918 10S05W06CAC1 550 170 70 99.90 3/27/2003

340709 914026 07S06W14BBC1 483 182 162 19.89 3/27/2003

Union County

330207 922109 19S12W28CBA1 25 200 190 10.35 4/30/2003

330824 923909 18S15W21DAC1 40 200 176 24.43 4/30/2003

331144 924116 17S15W31DCA2 110 253 203 49.92 3/05/2003

331219 921929 17S12W27DCA1 24 170 160 9.81 4/30/2003

331229 924601 17S16W33BBA2 31 255 230 25.25 4/30/2003

331402 922746 17S13W17DDC1 156 193 155 38.02 4/30/2003

331406 923037 17S14W14DDD1 20 135 130 4.59 4/30/2003

331453 925723 17S18W15CDA1 35 290 262 27.83 4/30/2003

331913 925704 16S18W22DCD1 36 247 239 7.86 3/06/2003

331915 925018 16S17W23BCC1 21 220 206 14.43 4/30/2003

Table 1. Information pertaining to measured wells completed in the Cockfield aquifer in southeastern Arkansas, 2003.—Continued

[In this report, the well latitudes and longitudes were measured using a global positioning system referenced to the North American Datum of 1983. ddmmss,

degrees, minutes, seconds; NGVD of 1929 refers to the National Geodetic Vertical Datum of 1929; --, no data]

Latitude

(ddmmss)

Longitude

(ddmmss)

Local well 

number

Well 

depth

(feet)

Land-surface

datum

altitude

(feet above

NGVD of 1929)

Water-level

altitude

(feet above

NGVD of 1929)

Depth to

water

(feet below

landsurface

datum)

Date of

measurement
Cockfield Formation 7

The regional direction of ground-water flow generally is 

towards the east and southeast, away from the outcrop, except 

in areas of intense ground-water withdrawals, such as near 

Crossett, Arkansas (Schrader and Joseph, 2000). A cone of 

depression is indicated by a relatively low water level near 

Crossett in Ashley County. Some local ground-water flow in the 

outcrop area is toward rivers that have eroded into the Cockfield 

Formation and deposited alluvium in south Bradley and Calhoun Counties (Ouachita River), and in north Dallas County 

(Saline River). The lowest water-level altitude measured was 62 

ft above NGVD of 1929 in Chicot County, near the Mississippi 

River; the highest water-level altitude measured was 353 ft 

above NGVD of 1929 in Columbia County, at the outcrop area. 

Water-Level Trends

Water-level trends in the Cockfield aquifer are illustrated 

by plotting the water levels in hydrographs, and evaluating the 

change in water level over a period of time. Historical waterlevel data from eight wells (wells A-H, fig. 3) in the Cockfield 

aquifer were plotted to illustrate the water-level trend in 

selected areas of southeastern Arkansas (fig. 4). An evaluation 

of 20 wells with water-level data from 1983 to 2003 shows that 

water levels in 15 wells have declined at a rate of -0.04 to -0.97 

ft/yr, and water levels in 5 wells have risen at a rate of 0.07 to 

0.32 ft/yr (table 2). Four of the 5 wells with rising water levels 

from 1983-2003 are within or near the recharge area of the 

Cockfield aquifer. An evaluation of the same 20 wells from 

2000 to 2003 shows that water levels have declined in only 8 

wells, and water levels have risen in 12 wells.
A. Arkansas County 08S02W04ACA1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

70

80

90

100

110

120

130

B. Ashley County 17S06W07ADA1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

70

80

90

100

110

120

130

8 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 4. Water-level altitudes for selected wells completed in the Cockfield aquifer in southeastern Arkansas.
C. Bradley County 14S10W31DBA1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

80

90

100

110

120

130

140

D. Chicot County 14S03W05BBA1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

50

60

70

80

90

100

110

 Cockfield Formation 9

Figure 4. Water-level altitudes for selected wells completed in the Cockfield aquifer in southeastern Arkansas.—Continued
E. Cleveland County 11S11W23BBD1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

200

210

220

230

240

250

260

F. Drew County 14S07W26BAB1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

90

100

110

120

130

140

150

10 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 4. Water-level altitudes for selected wells completed in the Cockfield aquifer in southeastern Arkansas.—Continued
G. Lincoln County 10S05W06CAC1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

50

60

70

80

90

100

110

H. Union County 17S13W17DDC1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

120

130

140

150

160

170

180

 Cockfield Formation 11

Figure 4. Water-level altitudes for selected wells completed in the Cockfield aquifer in southeastern Arkansas.—Continued
Table 2. Water-level trends for wells in the Cockfield aquifer that have water levels for the 20-year period from 1983 to 2003.

[In this report, negative values for change in water level refer to declines and positive values refer to rises]

Local well 

number

Difference in

water level

from 1983 to 2003

(feet)

Average annual

change in water 

level from

1983 to 2003

(feet/year)

Difference in

water level

from 2000 to 2003

(feet)

Average annual

change in water

level from

2000 to 2003

(feet/year)

Letter

corresponding

to hydrograph

in figure 4

Arkansas County

08S02W04ACA1 -17.81 -0.89 -2.12 -0.71 A

Ashley County

19S05W12CAC1 -2.75 -0.14 2.20 0.73

18S04W19DAA2 -3.75 -0.19 -0.64 -0.21

18S08W04BBC1 6.39 0.32 2.84 0.95

17S04W10BCD2 -11.73 -0.59 0.50 0.17

17S06W07ADA1 -1.29 -0.06 8.15 2.72 B

15S04W26CBC1 -11.34 -0.57 -2.97 -0.99

Bradley County

16S10W11DCB1 -2.57 -0.13 -8.55 -2.85

16S11W11ACA1 4.38 0.22 6.57 2.19

15S12W11CAB1 -0.90 -0.05 0.90 0.30

14S10W31DBA1 -10.07 -0.50 -1.58 -0.53 C

Chicot County

18S02W25ABB3 -1.49 -0.07 2.60 0.87

18S03W14CCC1 -2.10 -0.11 0.47 0.16

15S03W21ABA1 -11.23 -0.56 8.45 2.82

14S03W05BBA1 -19.39 -0.97 -0.93 -0.31 D

Cleveland County

11S11W23BBD1 2.13 0.11 2.98 0.99 E

Drew County

14S07W26BAB1 -8.10 -0.41 -1.91 -0.64 F

Lincoln County

10S05W06CAC1 -0.80 -0.04 1.53 0.51 G

Union County

17S15W31DCA2 1.32 0.07 -0.69 -0.23

17S13W17DDC1 2.96 0.15 1.57 0.52 H

12 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003
Wilcox Group 13

Wilcox Group

Hydrogeologic Setting

The Wilcox Group is Eocene age and distributed throughout most of southern and eastern Arkansas. There are two study 

areas for the potentiometric surface of the Wilcox in the southern and northeastern portions of Arkansas. The Wilcox Group 

in central Arkansas is not extensively used, and water-level data 

are insufficient to determine the potentiometric surface.

The Wilcox Group in the southern study area consists of 

interbedded layers of clay, sandy clay, sand, and lignite. Formations in the southern study area are undifferentiated. Sand beds 

generally are thin and are not continuous over large areas. In 

most of the southern study area, the Wilcox Group overlies the 

Midway Group and is overlain by terrace deposits and alluvium 

of Quaternary age or crops out in discontinuous bands that are 

1 to 3 miles wide. The Wilcox Group becomes progressively 

thicker down slope from the outcrop, ranging in thickness from 

a few feet in the outcrop to about 750 ft in northeastern Bradley 

County (Albin, 1964).

Recharge to the southern study area occurs by infiltration 

of rainfall in the outcrop areas and by inflow from overlying terrace and alluvial deposits; discharge flows to streams in the outcrop, to other formations where the aquifer is confined, and to 

wells (Westerfield, 1994). Well depths are shallow and well 

yields range from 10 to 100 gal/min (Schrader, 2002).

The Wilcox Group in most of the northeastern study area 

consists of thin interbedded layers of lignitic sand and clays. 

The Wilcox Group outcrops at or near Crowleys Ridge in Clay, 

Greene, and Craighead Counties (Broom and Lyford, 1981). 

East of Crowleys Ridge, the middle to lower part of the Wilcox 

Group contains a sand bed of 200 ft or more in thickness 

(Petersen and others, 1985) referred to as the “1,400-foot sand” 

(Ryling, 1960; Plebuch, 1961) or the “lower Wilcox aquifer” 

(Hosman and others, 1968). The Wilcox aquifer in the northeastern study area is confined above by a clay bed of the Wilcox 

Group and confined below by a clay bed of the Wilcox Group 

or the Midway Group.

Recharge to the northeastern study area occurs by infiltration of rainfall in the outcrop areas along the western side of 

Crowleys Ridge; discharge is mainly to wells and to flow 

beneath the Mississippi River into Mississippi (Westerfield, 

1994). Well depths range from 120 ft on Crowleys Ridge in 

Greene County to 1,750 ft in Crittenden County. Well yields 

range from 100 to 2,000 gal/min (Schrader, 2002).

Withdrawals from the Wilcox aquifer in the study areas 

totaled about 24 Mgal/d during 2000, most of which came from 

the northeastern study area (T.W. Holland, U.S. Geological 

Survey, written commun., 2003). In the southern study area, 

withdrawals were about 1 Mgal/d and the primary use of water 

from the aquifer was for domestic supplies, usually from wells 

on or near the outcrop areas. In the northeastern study area, 

withdrawals were about 23 Mgal/d and the primary use of water 

from the aquifer was for public supplies, but the aquifer is also 

a source of water for some commercial, domestic, and industrial 

users.

Potentiometric Surface

The potentiometric-surface maps show the altitude of the 

water surface in tightly cased wells screened in the Wilcox aquifer (figs. 5 and 6). The maps are based upon water-level data 

collected during March and April 2003, at 13 wells in the Wilcox aquifer southern study area and at 43 wells in the Wilcox 

aquifer northeastern study area (tables 3 and 4). The potentiometric surface was constructed by determining the water-level 

altitude in wells and constructing contour lines along points of 

equal water-level values. The direction of ground-water flow is 

perpendicular to the contours in the direction of decreasing 

water level.

The direction of ground-water flow in the southern study 

area generally is south and east, except in Clark County where 

flow is towards the Ouachita River that has eroded into the Wilcox Group and deposited alluvium. The lowest water-level altitude measured in southern Arkansas was 212 ft above NGVD 

of 1929 near the Ouachita River in Clark County; the highest 

water-level altitude measured was 401 ft above NGVD of 1929 

in the outcrop area of Hempstead County. 

The regional direction of ground-water flow in the northeastern study area generally is south and east. Ground-water 

withdrawals may have altered the natural direction of flow near 

the centers of pumping at Paragould and West Memphis 

(Joseph, 1998). The lowest water-level altitude measured in 

northeastern Arkansas was 121 ft above NGVD of 1929 near 

West Memphis in Crittenden County; the highest water-level 

altitude measured was 367 ft above NGVD of 1929 on Crowleys Ridge in Clay County. Crowleys Ridge represents an erosional remnant elevated as high as 200 ft above the Mississippi 

Alluvial Plain. Water levels measured in wells on Crowleys 

Ridge are higher because of the higher elevation of the Wilcox 

Group and influence of direct recharge to outcrops and subcrops 

on the ridge. The water levels on Crowleys Ridge were not 

included in the construction of the potentiometric surface 

because of limited control (four wells).

Water-Level Trends

Water-level trends in the Wilcox aquifer northeastern 

study area are illustrated by plotting the water levels in hydrographs, and evaluating the change in water level over a period 

of time. Historical water-level data from six wells (wells I-N, 

fig. 6) in the Wilcox aquifer were plotted to illustrate the waterlevel trend in selected areas of northeastern Arkansas (fig. 7). 

An evaluation of 27 wells with water-level data from 1983 to 

2003 in the northeastern study area shows that water levels in 

all 27 wells have declined at a rate of -0.17 to -1.73 ft/yr (table 

5). An evaluation of the same 27 wells from 2000 to 2003 shows 

that the water level rose in 18 wells and declined in 9 wells. 

Most of the wells that show water-level decline are near the center of pumping at West Memphis. The water-level trends for the 

Wilcox aquifer southern study area were not evaluated because 

of an insufficient period of data. 
300

340

280

320

260

360

240

220

380

220

380

320

300

240

340

360

280

260

272

316

293

329

340

393

401

328

337

255

231

212

265

CLARK

DALLAS

NEVADA

OUACHITA

Ouachita

HEMPSTEAD

HOT SPRING

River

Little

Missouri

River

93 30' o

92 30' o

34o

34 30' o

0 10 20 MILES

0 10 20 KILOMETERS

EXPLANATION

WELL COMPLETED IN WILCOX AQUIFER, SOUTHERN

ARKANSAS-- Number is water-level altitude

POTENTIOMETRIC CONTOUR--Shows altitude at which

water level would have stood in tightly cased wells. Contour

interval 20 feet. Datum is National Geodetic Vertical Datum

of 1929

OUTCROP OF WILCOX GROUP (from Hosman, 1988)

212

220

14 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 5. Potentiometric surface of the Wilcox aquifer in southern Arkansas, 2003.
150

142

176

177

173

177 185

169

212

216 184

202

204

188

189

197

195

183

189

189

174

147

180

167

163

157 154

121

143

139

142

205

201

197

193

190

189 197

295

352

296

367

190

K

I

M L

J

N

West

Memphis

Paragould

190

150

170

160

200

140

210

130

180

180

LEE

CLAY

CROSS

MISSISSIPPI

POINSETT

GREENE

CRAIGHEAD

ST FRANCIS

CRITTENDEN

0 10 20 MILES

0 10 20 KILOMETERS

35o

36o 90o

91o

EXPLANATION

WELL COMPLETED IN WILCOX

AQUIFER, NORTHEASTERN

ARKANSAS-- Number is water-level

altitude. Letter, where present,

corresponds to hydrograph in figure 7.

POTENTIOMETRIC CONTOUR--

Shows altitude at which water level

would have stood in tightly cased

wells. Contour interval 10 feet.

Datum is National Geodetic Vertical

Datum of 1929

180

I

180

CROWLEYS RIDGE

(from Hosman, 1988)

 Wilcox Group 15

Figure 6. Potentiometric surface of the Wilcox aquifer in northeastern Arkansas, 2003.
Table 3. Information pertaining to measured wells completed in the Wilcox aquifer in southern Arkansas, 2003.

[In this report, the well latitudes and longitudes were measured using a global positioning system referenced to the North American Datum of 1983. ddmmss, degrees, minutes, seconds; NGVD of 1929 refers to the National Geodetic Vertical Datum of 1929]

Latitude

(ddmmss)

Longitude

(ddmmss) Local well number

Well depth

(feet)

Land-surface

datum altitude

(feet above

NGVD of 1929)

Water-level

altitude

(feet above

NGVD of 1929)

Depth to

water

(feet below

land-surface

datum)

Date of

measurement

Clark County

335403 930612 10S20W01BAC1 53 295 265 29.75 03/25/2003

335611 925905 09S18W20CBB1 26 230 212 17.97 03/24/2003

340652 925757 07S18W20ABB2 19 242 231 11.29 03/24/2003

340917 925604 07S18W03BBD1 47 270 255 14.51 03/24/2003

Hempstead County

333017 933704 14S24W29BCA1 31 355 337 17.70 03/10/2003

333524 933635 13S24W29ACC1 60 371 328 43.08 03/10/2003

333829 933311 13S24W02DCA2 63 446 401 45.43 03/10/2003

Hot Spring County

341836 924853 05S17W10AAC1 26 410 393 17.23 03/03/2003

342144 924532 04S16W20CBB1 18 345 340 4.62 03/24/2003

Nevada County

333105 932443 14S22W19AAA1 75 337 329 8.25 03/12/2003

333754 931426 13S21W02DCC1 240 315 293 22.50 03/11/2003

334046 931941 12S22W24CDA1 41 344 316 27.58 03/11/2003

Ouachita County

334144 930105 12S19W11DCD1 533 288 272 15.59 03/13/2003

16 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003
 Wilcox Group 17

Table 4. Information pertaining to measured wells completed in the Wilcox aquifer in northeastern Arkansas, 2003.

[In this report, the well latitudes and longitudes were measured using a global positioning system referenced to the North American Datum of 1983. ddmmss, degrees, minutes, seconds; NGVD of 1929 refers to the National Geodetic Vertical Datum of 1929]

Latitude

(ddmmss)

Longitude

(ddmmss) Local well number

Well depth

(feet)

Land-surface

datum altitude

(feet above

NGVD of 1929)

Water-level

altitude

(feet above

NGVD of 1929)

Depth to

water

(feet below

land-surface

datum)

Date of

measurement

Clay County

362347 901703 20N07E01CBB1 200 460 367 92.85 04/17/2003

362716 901126 21N08E14CBB1 157 380 296 84.08 04/17/2003

Craighead County

354526 901911 13N07E14BBA2 1,028 221 197 23.71 04/16/2003

354737 903209 14N05E34DDD1 874 229 189 39.67 04/16/2003

354803 903208 14N05E34DAA1 865 230 190 39.64 04/16/2003

354843 903029 14N05E25DCB1 890 233 193 39.96 04/16/2003

354858 902613 14N06E27ACB2 999 227 197 30.36 04/16/2003

355008 902202 14N07E17DCB1 1,070 232 201 30.74 04/16/2003

355315 902107 15N07E33BAD1 1,034 232 205 26.87 04/16/2003

Crittenden County

345449 901828 04N07E36ADB1 1,638 201 142 58.87 04/14/2003

350129 902225 05N07E29ACC1 1,700 200 139 60.72 04/14/2003

350520 901807 06N07E01ABB1 1,541 207 143 64.25 04/14/2003

350907 901042 06N09E07CAC1 1,470 210 121 89.08 04/14/2003

351238 901148 07N08E24CAB1 1,540 221 154 66.87 04/14/2003

351318 901930 07N07E14CCC1 1,584 223 157 66.46 04/14/2003

351614 902752 08N06E33CBD1 1,750 215 163 52.39 04/14/2003

352225 901516 09N08E29ADD1 1,564 225 167 57.89 04/14/2003

Greene County

360123 903026 16N05E13BAB1 545 290 190 100.38 04/17/2003

360328 902902 17N06E31DCB1 462 285 180 104.85 04/17/2003

360348 903658 17N04E36BCA1 311 505 352 153.38 04/17/2003

361209 902520 18N06E10DCD1 120 320 295 24.63 04/17/2003

Lee County

345413 903136 03N05E01BAB1 1,702 196 147 49.44 04/09/2003
18 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Mississippi County

352923 901505 10N08E17ADD1 1,521 225 174 51.03 04/15/2003

353214 900739 11N09E33AAB1 1,560 237 189 47.98 04/15/2003

353349 900213 11N10E20ADA1 1,417 235 189 45.62 04/15/2003

353538 901301 11N08E10AAC2 1,380 220 183 37.09 04/15/2003

353917 895618 12N11E17CDD1 1,500 245 195 50.40 04/15/2003

354033 900548 12N09E11DBB1 1,452 230 197 33.07 04/15/2003

354221 895807 13N11E31CCC1 1,500 241 189 52.17 04/15/2003

354528 895547 13N11E08DDA1 1,445 245 188 56.52 04/15/2003

354859 895626 14N11E20CCA1 1,518 240 204 35.53 04/15/2003

355306 900952 15N09E31ACD1 1,158 240 202 37.98 04/15/2003

355426 894701 15N12E23DBC1 1,491 238 184 54.23 04/15/2003

355607 901527 15N08E08DBC3 1,060 238 216 22.24 04/15/2003

355712 895806 15N10E01ADC1 1,350 248 212 36.25 04/15/2003

Poinsett County

352925 902129 10N07E16CBB2 1,500 218 169 49.40 04/21/2003

353152 902520 11N06E35CDA3 1,301 215 185 29.87 04/21/2003

353234 903009 11N05E36AAA1 1,175 214 177 36.57 04/21/2003

353622 903618 11N05E06CCD1 992 214 173 41.50 04/21/2003

353629 901955 11N07E03BDD1 1,456 216 177 38.92 04/21/2003

354038 903059 12N05E13BBB1 1,071 222 176 45.59 04/21/2003

St. Francis County

345649 902815 04N06E21BAD2 1,740 201 142 59.38 04/09/2003

345712 902830 04N06E16CCB1 1,615 202 150 51.86 04/09/2003

Table 4. Information pertaining to measured wells completed in the Wilcox aquifer in northeastern Arkansas, 2003.—Continued

[In this report, the well latitudes and longitudes were measured using a global positioning system referenced to the North American Datum of 1983. ddmmss, degrees, minutes, seconds; NGVD of 1929 refers to the National Geodetic Vertical Datum of 1929]

Latitude

(ddmmss)

Longitude

(ddmmss) Local well number

Well depth

(feet)

Land-surface

datum altitude

(feet above

NGVD of 1929)

Water-level

altitude

(feet above

NGVD of 1929)

Depth to

water

(feet below

land-surface

datum)

Date of

measurement
I. Craighead County 14N07E17DCB1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

180

190

200

210

220

230

240

J. Crittenden County 07N07E14CCC1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

140

150

160

170

180

190

200

 Wilcox Group 19

Figure 7. Water-level altitudes for selected wells completed in the Wilcox aquifer in northeastern Arkansas.
K. Greene County 17N06E31DCB1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

160

170

180

190

200

210

220

L. Mississippi County 12N09E11DBB1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

180

190

200

210

220

230

240

20 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003

Figure 7. Water-level altitudes for selected wells completed in the Wilcox aquifer in northeastern Arkansas.—Continued
M. Poinsett County 12N05E13BBB1

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

160

170

180

190

200

210

220

N. St. Francis County 04N06E21BAD2

DATE

1/1/65 1/1/70 1/1/75 1/1/80 1/1/85 1/1/90 1/1/95 1/1/00 1/1/05

WATER LEVEL, IN FEET ABOVE NGVD OF 1929

140

150

160

170

180

190

200

 Wilcox Group 21

Figure 7. Water-level altitudes for selected wells completed in the Wilcox aquifer in northeastern Arkansas.—Continued
Table 5. Water-level trends for wells in the Wilcox aquifer that have water levels for the 20-year period from 1983 to 2003. 

[In this report, negative values for change in water level refer to declines and positive values refer to rises; ft, feet; ft/yr, feet per year]

Local well 

number

Difference in

water level

from 1983 to 2003

(ft)

Average annual

change in

water level

from 1983 to 2003

(ft/yr)

Difference in

water level

from 2000 to 2003

(ft)

Average annual

change in

water level

from 2000 to 2003

(ft/yr)

Letter

corresponding

to hydrograph 

in figure 7

Craighead County

13N07E14BBA2 -8.62 -0.43 14.95 4.98

14N06E27ACB2 -12.83 -0.64 6.08 2.03

14N07E17DCB1 -10.86 -0.54 6.22 2.07 I

Crittenden County

04N07E36ADB1 -34.54 -1.73 -3.99 -1.33

05N07E29ACC1 -32.59 -1.63 -4.25 -1.42

06N07E01ABB1 -30.59 -1.53 -3.32 -1.11

06N09E07CAC1 -28.15 -1.41 -3.36 -1.12

07N08E24CAB1 -20.84 -1.04 -0.19 -0.06

07N07E14CCC1 -23.07 -1.15 3.35 1.12 J

08N06E33CBD1 -20.42 -1.02 1.65 0.55

09N08E29ADD1 -21.04 -1.05 -2.69 -0.90

Greene County

17N06E31DCB1 -5.59 -0.28 10.32 3.44 K

17N04E36BCA1 -3.43 -0.17 4.83 1.61

Mississippi County

10N08E17ADD1 -21.85 -1.09 -0.61 -0.20

11N09E33AAB1 -10.18 -0.51 6.29 2.10

11N10E20ADA1 -11.62 -0.58 1.66 0.55

11N08E10AAC2 -15.40 -0.77 14.19 4.73

12N11E17CDD1 -4.66 -0.23 22.06 7.35

12N09E11DBB1 -9.47 -0.47 2.31 0.77 L

13N11E08DDA1 -24.72 -1.24 5.70 1.90

14N11E20CCA1 -11.50 -0.58 0.58 0.19

15N09E31ACD1 -12.36 -0.62 1.41 0.47

Poinsett County

10N07E16CBB2 -18.01 -0.90 -5.53 -1.84

11N06E35CDA3 -3.47 -0.17 8.81 2.94

11N07E03BDD1 -15.37 -0.77 7.50 2.50

12N05E13BBB1 -21.36 -1.07 1.28 0.43 M

St. Francis County

04N06E21BAD2 -31.96 -1.60 -3.46 -1.15 N

22 Potentiometric Surfaces in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2003
Summary 23

Summary

During March and April 2003, water levels were measured 

in 55 wells in the Cockfield aquifer, 13 wells in the Wilcox 

aquifer of southern Arkansas, and 43 wells in the Wilcox aquifer of northeastern Arkansas. Major withdrawals are made from 

the aquifers for industrial and public supply, with lesser but 

locally significant withdrawals for domestic and livestock uses. 

This report presents the results of the water-level measurements 

made during 2003 and displays the water levels in potentiometric-surface maps, in hydrographs, and describes water-level 

trends for wells with data from 1983 to 2003.

The Cockfield Formation generally consists of discontinuous sand units interbedded with silt, clay, and lignite in southeastern Arkansas. Most recharge occurs by rainfall infiltration 

on the outcrop and by inflow from overlying alluvium. Sand 

beds near the base of the Cockfield Formation constitute most 

of the Cockfield aquifer. Withdrawals from the Cockfield aquifer study area during 2000 totaled about 9 million gallons per 

day.

The potentiometric surface of the Cockfield aquifer constructed from the 2003 water levels shows that regional direction of ground-water flow generally is towards the east and 

southeast, away from the outcrop, except in areas of intense 

ground-water withdrawals, such as near Crossett, Arkansas. A 

cone of depression is indicated by a relatively low water level 

near Crossett in Ashley County. Some local ground-water flow 

in the outcrop area is toward rivers that eroded into the Cockfield Formation and deposited alluvium in south Bradley and 

Calhoun Counties (Ouachita River), and in north Dallas County 

(Saline River). Water-level measurements at wells completed in 

the Cockfield aquifer ranged in altitude from 62 to 353 ft above 

NGVD of 1929. An evaluation of 20 wells with water-level data 

from 1983 to 2003 shows that water levels in 15 wells have 

declined at a rate of -0.04 to -0.97 ft/yr, and water levels in 5 

wells have risen at a rate of 0.07 to 0.32 ft/yr. Four of the 5 wells 

with rising water levels are within or near the recharge area of 

the Cockfield Formation. An evaluation of the same 20 wells 

from 2000 to 2003 shows that water levels in the wells have 

declined in only 8 wells and risen in 12 wells.

The Wilcox Group is distributed throughout most of southern and eastern Arkansas. There are two study areas in southern 

and northeastern Arkansas. The Wilcox Group of the southern 

study area consists of interbedded clay, sandy clay, sand, and 

lignite. Recharge occurs by rainfall infiltration in the outcrop or 

inflow from overlying terrace and alluvial deposits. Thin discontinuous sand units constitute the Wilcox aquifer in the 

southern study area. Withdrawals from the aquifer in the southern study area were about 1 million gallons per day in 2000. The 

potentiometric surface of the Wilcox aquifer in the southern 

study area shows that regional ground-water flow generally is 

south and east, except in Clark County where flow is towards 

the Ouachita River. Water-level measurements in the southern 

study area ranged from 212 to 401 ft above NGVD of 1929. 

There was an insufficient period of data to evaluate water-level 

trends for the Wilcox aquifer southern study area.

The Wilcox Group in the northeastern study area consists 

of thin interbedded lignitic sand and clays. Recharge occurs by 

rainfall infiltration in the outcrop along Crowleys Ridge. A sand 

bed about 200 ft thick in the middle to lower part of the Wilcox 

Group constitutes the major producing unit of the Wilcox aquifer in the northeastern study area. Withdrawals from the aquifer 

in the northeastern study area were about 23 million gallons per 

day during 2000.

The potentiometric surface of the Wilcox aquifer in the 

northeastern study area shows that ground-water flow generally 

is south and east, except where ground-water withdrawals may 

have altered the natural direction of flow near the centers of 

pumping at Paragould and West Memphis. Water-level measurements at wells completed in the northeastern study area 

ranged from 121 to 367 ft above NGVD of 1929. An evaluation 

of 27 wells with water-level data from 1983 to 2003 in the 

northeastern study area shows that water levels in all 27 wells 

have declined at a rate of -0.17 to -1.73 ft/yr. An evaluation of 

the same 27 wells from 2000 to 2003 shows that water levels in 

18 wells have risen and in 9 wells have declined. Most of the 

water-level declines in wells are near the center of pumping at 

West Memphis. 

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Yeatts, D.S.—POTENTIOMETRIC SURFACES IN THE COCKFIELD AND WILCOX AQUIFERS OF SOUTHERN AND NORTHEASTERN

ARKANSAS, 2003—U.S. Geological Survey Scientific Investigations Report 2004-5169