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T

RANSPORTATION AND DEVELOPMENT

U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

Louisiana Department of Transportation and Development - U.S. Geological Survey Water Resources Cooperative Program

Prepared in cooperation with the

LOUISIANA DEPARTMENT OF TRANSPORTATION AND DEVELOPMENT

PUBLIC WORKS AND WATER RESOURCES DIVISION

WATER RESOURCES SECTION

INTRODUCTION

Previous investigators have determined that the Sparta aquifer is made up of several massive (major) sands. 

The individual sands are separated locally by layers of clay, but on a regional basis act as one unit (Payne, 1968). The Sparta aquifer serves as a source of ground water for 16 parishes in northern Louisiana, and is the principal source of ground water for Bienville, Claiborne, Jackson, Lincoln, Morehouse, Ouachita, Union, Webster, and Winn Parishes. Municipalities in the State began withdrawing water from the aquifer for public supply in the late 19th century. The withdrawal of water from the aquifer for industrial purposes began at Bastrop in 1922 and at West Monroe in 1923 (Sanford, 1973a). Since then, the demand for water has continued to increase, and water levels throughout much of the aquifer have declined steadily. In 2000, the Sparta aquifer provided a total of 77.2 Mgal/d of water for public supply, industry, power generation, rural domestic supply, livestock, irrigation, and aquaculture. This amount was a 12.6 percent increase in withdrawals since 1990 (J.K. Lovelace, U.S. Geological Survey, oral and written communs., 2000).

 The decline in water levels have prompted concern about the capability of the aquifer to meet future demands 

for freshwater (water containing less than 250 mg/L of chloride, U.S. Environmental Protection Agency, 1994). Additional knowledge about the thickness and areal extent of major sands and the effects of water withdrawals on the Sparta aquifer is essential in assessing the aquifer’s potential as a sustained source of water for present and future needs and for protection of the resource. In 1996, the U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation and Development, began a study of the Sparta aquifer in northern Louisiana to develop a data base of digital geophysical logs from boreholes, to determine the thickness and areal extent of major sands, and to evaluate the potentiometric surface. The study area included all or parts of 16 parishes in northern Louisiana.

Purpose and Scope

This report describes the thickness and areal extent of the Sparta aquifer, identifies sands within the freshwater extent of the aquifer, and presents data and a map that illustrate the generalized potentiometric surface (water 

levels) during October 1996. The report includes a detailed geophysical log, structure contour maps, hydrogeologic sections, and hydrographs of water levels in selected wells. The potentiometric surface-map can be used for determining direction of ground-water flow, hydraulic gradients, and the effects of withdrawals on the aquifer.

Data Collection and Methods

Correlations of the sands were accomplished by selecting and analyzing geophysical and drillers’ logs in 

the study area. The geophysical logs were selected on the basis of geographic location, log depth, and log quality. The geophysical logs from 574 water and oil wells were digitized to develop a digital data base. The wells were located in Bienville, Bossier, Caddo, Caldwell, Claiborne, Jackson, Lincoln, Morehouse, Natchitoches, Ouachita, Richland, Sabine, Union, Webster, and Winn Parishes. For quality-control purposes, the digital geophysical logs were compared with the original geophysical log printouts. When possible, the geophysical log data were used to identify the top, base, and individual sands of the Sparta aquifer, and to prepare structure contour maps of the top and base of the aquifer.

 Geophysical logs from 45 wells were used in preparation of five hydrogeologic sections. The sections were 

constructed to represent the extent of the aquifer. Three sections were oriented west to east, and two sections were oriented north to south. Sands were determined for the wells by analyzing the geophysical log data. In general, areas of sand or shale less than 20 ft thick were not differentiated in the sections. 

 Water-level measurements collected during October 1996 from 55 wells were used in the construction of the 

generalized potentiometric-surface map. The water-level data were collected from wells located throughout the freshwater extent of the Sparta aquifer in Louisiana. The data were collected by USGS personnel in accordance with methods described by the USGS, Office of Ground Water. The data were entered into the USGS National Water Information System data base. 

Previous Investigations

Reports from previous investigations of the hydrogeology in the study area were reviewed. Payne (1968) 

described the thickness, sand percentage, lithologic variations, and hydrologic characteristics of the Sparta aquifer in Mississippi, Louisiana, Arkansas, and Texas. Sanford (1973b) studied water use and water resources of the Ruston area, and in a similar manner, Ryals (1982) described the ground-water resources of the Arcadia-Minden area. Trudeau and Buono (1985) discussed the effects increased pumpage in the Sparta aquifer near West Monroe could have on water levels and salinity. McWreath and others (1991) modeled potentiometric responses to pumping stresses in the Sparta aquifer in northern Louisiana and southern Arkansas. The potentiometric surface of the Sparta aquifer has been previously mapped by Ryals (1980) and Smoot and Seanor (1991). Water from the Sparta aquifer is moderately hard, 61 to 120 mg/L (Stuart and others, 1994) and suitable for use without treatment, although water in some areas may require treatment to remove excess iron (Ryals, 1982; Page and May, 1964; Sanford, 1973b). Freshwater occurs throughout most of the study area. Chloride concentrations within the Sparta aquifer generally increase in a downdip direction (McWreath and others, 1991).

Acknowledgments

Special thanks are given to Zahir "Bo" Bolourchi, Chief, Water Resources Section, Louisiana Department of 

Transportation and Development, for assistance provided during the study and during preparation of the report; and to Dan Tomaszewski for his contribution to the analysis and interpretation of geophysical logs and the compilation of the report.

HYDROGEOLOGY

The Sparta aquifer is one hydrogeologic unit in a series of alternating aquifers and confining units within the 

Mississippi Embayment. The Sparta aquifer, of Eocene age, is situated between the massive marine clay layers of the overlying Cook Mountain and underlying Cane River confining units (Snider and others, 1972). For this study, the top of the Sparta aquifer is defined as the base of the overlying Cook Mountain confining unit. The base of the Sparta aquifer is defined as the top of the underlying Cane River confining unit.

The lithology of the Sparta aquifer is highly varied both laterally and vertically. The Sparta aquifer consists 

of very fine to medium sand, silty clay, lignite, and clay. The aquifer has beds of fine to medium sand in the lower half and beds of sand, clay, and lignite in the upper half. The existing pattern of sand concentrations in the aquifer has been attributed to deposition by constantly shifting stream channels and interlacing lakes, marshes, and swamps of a deltaic-fluvial flood plain (Payne, 1968). Individual sands within the Sparta aquifer may act locally, for short periods of time, as separate hydraulic units. However, over longer periods of time and larger areas, these sands act together as a unified aquifer (Payne, 1968). Pumpage from the basal parts of the aquifer may affect water levels in the middle and upper parts (McWreath and others, 1991). This is dependent on how well the individual sands are hydraulically connected, and the duration and rate of pumping.

The percentage of sand within individual sands of the Sparta aquifer can vary from being almost completely 

sand (as typified by the thick sands generally present near the base of the Sparta aquifer) to approximately 50 percent sand, as seen in well Ou-466, which contains thin sands broken with many small clays (fig. 1).

In most of the study area, the altitude of the top of the Sparta aquifer ranges from approximately 200 ft above 

sea level near the recharge area to approximately 300 ft below sea level near the downdip limit of freshwater (fig. 2). The top of the aquifer generally dips east and southeast at a rate of 5 to 25 ft/mi. The altitude of the top of the Sparta aquifer in southern Natchitoches and Sabine Parishes range from sea level in the recharge area to approximately 1,300 ft below sea level near the downdip limit of freshwater. In this area, the aquifer dips at a rate greater than 60 ft/mi (fig. 2). 

The altitude of the base of the Sparta aquifer ranges from approximately 150 ft above sea level in the 

recharge area to approximately 1,000 ft below sea level near the downdip limit of freshwater (fig. 3). The base of the aquifer dips east and southeast at a rate of 25 to 50 ft/mi. The altitude of the base of the Sparta aquifer in southern Natchitoches and Sabine Parishes ranges from approximately 100 ft below sea level in the recharge area to approximately 1,400 ft below sea level near the downdip limit of freshwater (fig. 3).

Figure 2. Altitude of the top of the Sparta aquifer in northern Louisiana. Figure 3. Altitude of the base of the Sparta aquifer in northern Louisiana.

Figure 1. Geophysical log and lithologic description of well Ou-466, Ouachita Parish, 

Louisiana.

Louisiana Ground-Water Map No. 13

Hydrogeology and Potentiometric Surface of the Sparta Aquifer in 

Northern Louisiana, October 1996

By

Jeffrey A. Brantly, Ronald C. Seanor, and Kaycee L. McCoy 

2002
DOTD

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T

RANSPORTATION AND DEVELOPMENT

U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

Louisiana Department of Transportation and Development - U.S. Geological Survey Water Resources Cooperative Program

Prepared in cooperation with the

LOUISIANA DEPARTMENT OF TRANSPORTATION AND DEVELOPMENT

PUBLIC WORKS AND WATER RESOURCES DIVISION

WATER RESOURCES SECTION

Louisiana Ground-Water Map No. 13

Hydrogeology and Potentiometric Surface of the Sparta Aquifer in 

Northern Louisiana, October 1996

By

Jeffrey A. Brantly, Ronald C. Seanor, and Kaycee L. McCoy 

2002

Figure 4. West-to-east hydrogeologic section (A-A’) through the Sparta aquifer in northern Louisiana. Figure 6. W

Figure 7. North-to-south hydrogeologic section (D-D’) through the Sparta aquifer

in northern Louisiana.

Figure 5. West-to-east hydrogeologic section (B-B’) through the Sparta aquifer in northern Louisaina.

Figure 8. North-to-south hydrogeologic 
Table 1: Water-level data used to construct the potentiometric surface of 

the Sparta aquifer in Louisiana, October 1996

———————————————————————————

Well Water level Water level

Well

number

depth

(feet)

(feet below

land surface)

(feet above or

below sea level)

Date

measured

———————————————————————————

Bienville Parish

———————————————————————————

Bi-76 110 50.46 229.54 10-01-96Bi-100 90 33.21 186.79 10-16-96Bi-112 348 115.82 99.18 10-01-96

Bi-144 630 236.42 83.58 10-01-96Bi-166 472 181.43 78.57 10-01-96Bi-186 216 41.97 138.03 10-16-96

Bi-192 153 74.49 210.51 10-16-96Bi-216 300 16.70 183.30 10-01-96

———————————————————————————

Caldwell Parish

———————————————————————————

Ca-86B 545 79.28 80.72 10-01-96

———————————————————————————

Claiborne Parish

———————————————————————————

Cl-9 670 270.01 89.99 10-09-96Cl-58 488 140.01 109.99 10-09-96Cl-111 570 255.46 44.54 10-08-96

Cl-116 684 259.73 -14.73 10-10-96Cl-148 625 196.80 -6.80 10-10-96Cl-149 736 294.36 -64.36 10-10-96

———————————————————————————

Jackson Parish

———————————————————————————

Ja-49 570 201.19 -41.19 10-02-96

Ja-147 703 246.47 -26.47 10-16-96

Ja-148 578 225.15 19.85 10-02-96

———————————————————————————

Lincoln Parish

———————————————————————————

L-26 686 180.27 -25.27 10-10-96L-68 770 249.60 -69.60 10-10-96

L-113 750 317.56 37.44 10-02-96L-117 551 137.85 -51.85 10-15-96

———————————————————————————

Morehouse Parish

———————————————————————————

Mo-5 860 153.52 -36.08 10-04-96

Mo-342 620 89.85 -1.51 10-03-96

Mo-350 740 105.56 6.52 10-03-96

———————————————————————————

Ouachita Parish

———————————————————————————

Ou-80 176 283.76 -223.76 10-10-96

Ou-401A 397 106.13 -43.85 10-10-96Ou-402 750 58.98 4.32 10-10-96

Ou-404 167 80.32 -19.43 10-15-96

Ou-406 681 157.25 -90.50 10-10-96Ou-444 670 229.09 -111.09 10-23-96

Ou-488 255 332.73 -52.73 10-23-96

———————————————————————————

Union Parish

———————————————————————————

Un-26 745 184.00 -50.08 10-04-96Un-78 727 208.60 -33.60 10-24-96Un-79 749 153.40 -35.40 10-24-96Un-83 326 174.00 -52.00 10-16-96Un-84 696 248.70 -38.70 10-24-96Un-86 655 100.63 -10.63 10-16-96Un-134 585 307.13 -87.13 10-23-96

———————————————————————————

Webster Parish

———————————————————————————

Wb-127 408 61.37 208.63 10-21-96Wb-164 769 64.32 155.68 10-07-96Wb-219 136 5.17 184.83 10-08-96

Wb-271 220 84.25 193.75 10-09-96Wb-285 608 180.68 159.32 10-08-96Wb-326 470 114.51 145.49 10-04-96Wb-338 425 94.89 135.11 10-04-96Wb-349 263 70.38 109.62 10-07-96

Wb-359 687 79.68 200.32 10-09-96Wb-399 298 45.24 159.76 10-04-96Wb-415 544 17.20 142.80 10-09-96

———————————————————————————

Winn Parish

———————————————————————————

W-28 606 52.14 52.86 10-01-96

W-144B 550 37.55 102.45 10-01-96W-172 655 91.21 48.79 10-01-96

W-177 695 53.34 131.66 10-01-96W-179 585 108.70 86.30 10-01-96

———————————————————————————

DOTD

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RANSPORTATION AND DEVELOPMENT

U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

Louisiana Department of Transportation and Development - U.S. Geological Survey Water Resources Cooperative Program

Prepared in cooperation with the

LOUISIANA DEPARTMENT OF TRANSPORTATION AND DEVELOPMENT

PUBLIC WORKS AND WATER RESOURCES DIVISION

WATER RESOURCES SECTION

POTENTIOMETRIC SURFACE

A map of the generalized potentiometric surface of the Sparta aquifer 

for October 1996, was constructed using water-level measurements from 55 wells completed in the middle or lower part of the aquifer. The altitude of water level contours ranged from 220 ft above sea level in the recharge areas of Bienville and Webster Parishes to 220 ft below sea level in Ouachita Parish (fig. 9). These contours show highest water levels in the western recharge area, and lowest water levels at major pumping centers. Flow lines illustrated on the potentiometric map in figure 9 show ground-water movement is toward areas of intensive pumpage. Major pumping centers in Louisiana are located at West Monroe (20 Mgal/d), and Hodge (20 Mgal/d). The Sparta aquifer is also impacted by pumpage in the Ruston (8 Mgal/d), Minden (6 Mgal/d), and Winnfield (1 Mgal/d) areas of Louisiana, as well as pumpage from El Dorado, Arkansas (J.K. Lovelace, U.S. Geological Survey, oral and written communs., 2000). Data collected subsequent to the data used in this potentiometricsurface map seem to indicate the presence of a cone of depression around the Ruston area.

Well Wb-399 is located in the recharge area and is screened between a 

depth of 288 and 298 ft. The hydrograph in figure 10 shows only seasonal fluctuations in water levels for the period of record from 1979 to 2000 and no net increase or decrease. This well is typical of wells located in the recharge area of the Sparta aquifer.

Typical regional declines in water levels in the Sparta aquifer are 

shown by wells Cl-149 (fig. 11), located near the Louisiana-Arkansas State line, and well L-26 (fig. 12), located north of Ruston. For the periods of record, water levels in wells Cl-149 and L-26 have declined approximately 1.5 and 2.0 ft/yr, respectively. These regional declines are a result of longterm withdrawals from the Sparta aquifer.

Wells Ou-443, Ou-444, and Ou-445 are located west of West Monroe. 

Each well is completed in a different sand separated vertically by layers of clay which results in the wells being hydraulically isolated on a local basis. All three wells have shown an average water-level decline of about 2.0 ft/yr for the same period of record. Hydrographs for all three wells indicate water levels undergo very similar fluctuations (fig. 13). Therefore, water levels of individual sands in this area indicate a hydraulic connection between individual sands within the Sparta aquifer.

SUMMARY AND CONCLUSIONS

The Sparta aquifer serves as the principal source of ground water for 

Bienville, Claiborne, Jackson, Lincoln, Morehouse, Ouachita, Union, Webster, and Winn Parishes. Pumpage from the massive sands in the lower part of the aquifer may affect the upper sands. Analysis of the hydrogeologicsections, as well as the water-level data, indicate that parts of the Sparta aquifer are well-connected hydraulically. The aquifer framework is constructed of imperfectly connected sands which may act as separate hydraulic units for short periods of time, but due to the depositional nature of the aquifer, act as one unit regionally. 

In northern Louisiana, the altitude of the top of the Sparta aquifer 

ranges from 200 feet above sea level in the recharge areas to approximately 300 feet below sea level near the downdip limit of freshwater and dips east and southeast at a rate of 5 to 25 feet per mile. The altitude of the base of the Sparta aquifer ranges from 150 feet above sea level in recharge areas to approximately 1,000 feet below sea level near the downdip limit of freshwater and dips east and southeast at a rate of 25 to 50 feet per mile.

Hydrogeologic-sections show the thickness and linear extent of sands 

within the Sparta aquifer. Along the sections, the Sparta aquifer ranges in thickness from approximately 140 feet adjacent to the recharge areas to approximately 725 feet near the downdip limit of freshwater.

Water levels in the Sparta aquifer have steadily declined since the early 

1920’s when industrial pumpage began. The 1996 potentiometric surface shows that water levels have generally declined approximately 20 feet (2.8 feet per year) since 1989, except in the recharge areas where water levels have remained relatively constant. In 2000, the Sparta aquifer provided a total of 77.2 million gallons per day for public supply, industry, power generation, rural domestic supply, livestock, irrigation, and aquaculture. From 1990 to 2000, withdrawals from the Sparta aquifer increased 12.6 percent.

SELECTED REFERENCES

Clark, G.C., 1959, Interior salt domes of Texas, Louisiana, and Mississippi: Interior -----1973b, Water resources of the Ruston area, Louisiana: Louisiana Department 

salt domes and Tertiary stratigraphy of Louisiana: Shreveport Geological of Public Works Water Resources Technical Report no. 8, 32 p.Society, 1960, 147 p. Smoot, C.W., and Seanor, R.C., 1991, Louisiana ground-water map no. 3: 

Lovelace, J.K., 1991, Water use in Louisiana, 1990: Louisiana Department of Potentiometric surface, 1989, and water level changes, 1980-89, of the Sparta 

Transportation and Development Water Resources Special Report no. 6, 131 p. aquifer in north-central Louisiana: U.S. Geological Survey Water-Resources 

Investigations Report 90-4183, 2 sheets. Lovelace, J.K., and Johnson, P.M., 1996, Water use in Louisiana,1995: Louisiana 

Department of Transportation and Development Water Resources Special Stuart, C.G., Knochenmus, Darwin, and McGee, B.D., 1994, Guide to Louisiana’s 

Report no. 11, 127 p. ground-water resources: U.S. Geological Survey Water-Resources 

Investigations Report 94-4085, 55 p. McWreath, H. C. III, Nelson, J. D., and Fitzpatrick, D. J., 1991, Simulated response 

to pumping stresses in the Sparta aquifer, northern Louisiana and southern Snider, J.L., Calandro, A.J., and Shampine, W.J., 1972, Water resources of Union Arkansas: Louisiana Department of Transportation and Development Water Parish, Louisiana: Department of Conservation, Louisiana Geological Resources Technical Report no. 51, 51 p. Survey, and Louisiana Department of Public Works Water Resources Bulletin 

no. 17, 68 p. Payne, J.N., 1968, Hydrologic significance of the lithofacies of the Sparta Sand in 

Arkansas, Louisiana, Mississippi, and Texas: U.S. Geological Survey Trudeau, D.A., Buono, Anthony, 1985, Projected effects of proposed increased 

Professional Paper 569-A, p. A1-A17. pumpage on water levels and salinity in the Sparta aquifer near West Monroe, 

Louisiana: Louisiana Department of Transportation and Development Water Page, L.V., and May, H.G., 1964, Water resources of Bossier and Caddo Parishes, Resources Technical Report no. 39, 70 p. Louisiana: Department of Conservation, Louisiana Geological Survey, and 

Louisiana Department of Public Works Water Resources Bulletin no. 5, 105 p. U.S. Environmental Protection Agency, 1994, Drinking water regulations and 

health advisories: U.S. Environmental Protection Agency, Office of Water, Ryals, G.N., 1980, Potentiometric surface maps of the Sparta Sand; northern May 1994, EPA 822-R-94-001,11 p. Louisiana and southern Arkansas, 1900, 1965, 1975, and 1980: U.S. 

Geological Survey Open-File Report 80-1180, 1 sheet. In this report, “sea level” refers to the National Geodetic Vertical Datum 

-----, 1982, Ground-water resources of the Arcadia-Minden area, Louisiana: of 1929--a geodetic datum derived from a general adjustment of the first- Louisiana Department of Transportation and Development, Office of Public order level nets of both the United States and Canada, formerly called Sea 

Works Water Resources Technical Report no. 28, 35 p. Level Datum of 1929.

Sanford, T.H., Jr., 1973a, Ground-water resources of Morehouse Parish, Louisiana: Any use of trade, product, or firm names is for descriptive purposes only and Department of Conservation, Louisiana Geological Survey, and Louisiana does not imply endorsement by the U.S. Government. Department of Public Works Resources Bulletin no. 19, 90 p.

Figure 10. Water level in well Wb-399 (Webster Parish).

Figure 13. Wat

Figure 12. Wate

Figure 9. Potentiometric surface of the Sparta aquifer in northern Louisiana, October 1996.

Louisiana Ground-Water Map No. 13

Hydrogeology and Potentiometric Surface of the Sparta Aquifer in 

Northern Louisiana, October 1996

By

Jeffrey A. Brantly, Ronald C. Seanor, and Kaycee L. McCoy 

2002

Figure 11. Water level in well Cl-149 (Claiborne Parish).