U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3010

March 2017

Water Resources of the Southern Hills Regional Aquifer 

System, Southeastern Louisiana

Introduction 

Information concerning the availability, use, and quality of groundwater in the 10 parishes overlying the Southern Hills regional 

aquifer system of Louisiana (fig. 1) is critical for water-supply management. The purpose of this fact sheet is to present information 

that can be used by water managers, residents, and others for stewardship of this vital resource. Information on the availability, past 

and current use, use trends, and water quality from groundwater sources in these parishes is presented. Previously published reports 

(see References Cited section) and data stored in the U.S. Geological Survey’s National Water Information System (U.S. Geological 

Survey, 2017) are the primary sources of the information presented here.

Groundwater Withdrawals

In 2014, about 293 million gallons 

per day (Mgal/d) (table 1; fig. 2) were 

withdrawn from groundwater sources in 

the 10-parish area (West Feliciana, East 

Baton Rouge, East Feliciana, Livingston, 

Pointe Coupee, St. Helena, St. Tammany, 

Tangipahoa, Washington, and West 

Baton Rouge; figs. 1, 2) that overlies 

the Southern Hills regional aquifer 

system (Buono, 1983; U.S. Geological 

Survey, 2016).1

 Most of the groundwater 

1

Water-withdrawal data are based on estimated or 

reported site-specific data and aggregated data, which 

are distributed to sources. For a full description 

of water-use estimate methodology, see “Data 

Collection” in Sargent (2011). Tabulation of numbers 

in text and tables may result in different totals 

because of rounding; nonrounded numbers are used 

for calculation of totals.

withdrawals come from the regional 

aquifer system, but in the western part 

of the study area, the Mississippi River 

alluvial aquifer is also a major source. 

Withdrawals for public supply accounted 

for about 48 percent (140.34 Mgal/d), 

and industrial use accounted for about 

32 percent (94.34 Mgal/d) of the total 

withdrawn (table 1). Other categories 

of use included power generation, rural 

domestic, livestock, general irrigation, 

rice irrigation, and aquaculture. Water-use 

data collected at 5-year intervals from 

1960 to 2010 and again in 2014 (fig. 2) 

indicated that groundwater withdrawals 

peaked in 2014. These withdrawals were 

highest in East Baton Rouge Parish 

(148.26 Mgal/d) and lowest in St. Helena 

Parish (1.79 Mgal/d) (fig. 1). 

Table 1. Groundwater withdrawals, 2014, 

in million gallons per day, by use category 

in the 10-parish area overlying the Southern 

Hills regional aquifer system, Louisiana 

(U.S. Geological Survey, 2016).

Use category Groundwater

Public supply 140.34

Industrial 94.34

Power generation 9.69

General irrigation 23.18

Rice irrigation 3.47

Rural domestic 12.83

Livestock 0.57

Aquaculture 8.23

Total 292.65

Base modified from U.S. Geological Survey digital data

Albers Equal-Area Conic projection

North American Datum of 1983 20 KILOMETERS

0

0

10 20 MILES

10

90°00' 90°30' 91°00' 91°30'

31°00'

30°30'

EXPLANATION

Groundwater withdrawals, in million

gallons per day (Mgal/d)

0 to 10

>10 to 20

>20 to 30

>30 to 50

>50 

Increasing

withdrawals

LOUISIANA

MISSISSIPPI

11.14 Mgal/d

148.26

Mgal/d

5.72 Mgal/d 22.99 Mgal/d

18.74 

Mgal/d

25.36 Mgal/d

41.03 Mgal/d

3.81 Mgal/d 1.79 Mgal/d

13.84 Mgal/d

LIVINGSTON PARISH

ST HELENA PARISH

EAST BATON ROUGE PARISH

EAST FELICIANA PARISH

TANGIPAHOA PARISH

WEST FELICIANA PARISH

WASHINGTON PARISH

ST TAMMANY PARISH

POINTE COUPEE PARISH

 WEST 

 BATON

 ROUGE

 PARISH

Study area

GULF OF MEXICO

TEXAS

MISSISSIPPI

ARKANSAS

LOUISIANA

Figure 1. Location of the 10-parish area overlying the Southern Hills regional aquifer system with 2014 groundwater 

withdrawals, Louisiana. Darker shading indicates greater withdrawal amount (U.S. Geological Survey, 2016).

ISSN 2327-6916 (print) ISSN 2327-6932 (online)

https://doi.org/10.3133/10.3133/fs20173010
laf17-0800_fig 02

0

50

100

150

200

250

300

350

Annual withdrawals, 

in million gallons per day

Year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2014

Figure 2. Groundwater withdrawals in the 10 parishes overlying 

the Southern Hills regional aquifer system in Louisiana, 1960–2014 

(U.S. Geological Survey, 2016).

Groundwater Resources

Fresh groundwater (water with a chloride 

concentration of 250 milligrams per liter [mg/L] or 

less) in the Southern Hills regional aquifer system in 

Louisiana is present in three aquifer systems: from 

shallowest to deepest, (1) the Chicot equivalent, 

(2) Evangeline equivalent, and (3) Jasper equivalent 

aquifer systems (figs. 3, 4). The Mississippi River 

alluvial aquifer is present along much of the western 

edge of East Baton Rouge and West Feliciana Parishes 

and within Pointe Coupee and West Baton Rouge 

Parishes. The Mississippi River alluvial aquifer is 

hydraulically connected to the Chicot equivalent 

aquifer system in localized areas but is not considered 

part of the Southern Hills regional aquifer system.

Base modified from U.S. Geological Survey digital data

Albers Equal-Area Conic projection

North American Datum of 1983

20 KILOMETERS

0

0

10 20 MILES

10

90°00' 90°30' 91°00' 91°30'

31°00'

30°30'

Mississippi River

Lake

Pontchartrain

 Lake 

Maurepas

Pearl River

Lake

 Killarney

Old River

Lake

Borgne

LOUISIANA

MISSISSIPPI

LIVINGSTON

PARISH

ST HELENA

PARISH

EAST

BATON ROUGE

PARISH

IBERVILLE

PARISH

EAST

FELICIANA

PARISH

TANGIPAHOA

 PARISH

WEST 

FELICIANA

PARISH

WASHINGTON

PARISH

ST TAMMANY

PARISH

ASCENSION

PARISH

POINTE

COUPEE

PARISH

WEST 

 BATON

 ROUGE

 PARISH

GULF OF MEXICO

Study area

TEXAS

ARKANSAS MISSISSIPPI

LOUISIANA

Approximate

Southern Hills

aquifer system

recharge area

BATON ROUGE FAULT

DENHAM SPRINGS-SCOTLANDVILLE FAULT

Jasper equivalent

aquifer system

Chicot equivalent

aquifer system

Evangeline equivalent

aquifer system

Evangeline equivalent

aquifer system

EB-146

EB-1000

EB-827

WF-222

Ta-268

Ta-278

Ta-362

SH-56

Li-122

Li-52

Li-185

Wa-158

Wa-13

ST-563

Port Allen

St Francisville

Clinton

Amite

Hammond

Baton Rouge

Slidell

Bogalusa Franklinton Greensburg

Denham Livingston Springs

New Roads

Covington

61

55

12

12 59

19

10

A

A'

EXPLANATION

Approximate altitude of base of fresh groundwater, in feet below the National

 Geodetic Vertical Datum of 1929 (NGVD 29)(modified from Smoot, 1988)—

 Deepest freshwater contained within the Jasper equivalent aquifer system,

 except where noted

 0 to 299

 300 to 499

 500 to 699

 700 to 999

 1,000 to 1,499

EB-146

A'A

Approximate area where intermediate sands contain saltwater

Approximate boundary of area showing deepest freshwater contained

 within overlying Chicot and Evangeline equivalent aquifer systems

Fault at ground surface—Dashed where approximately located

 (modified from Griffith, 2003 and Tomaszewski, 2011) 

Line of section (see fig. 4; modified from Griffith, 2003)

Well and number for which hydrograph is shown (see fig. 5)

 1,500 to 1,999

 2,000 to 2,499

 2,500 to 2,999

 3,000 to 3,499

 3,500 and deeper

Figure 3. Hydrogeologic features of the Southern Hills regional aquifer system in the study area with section line and well locations 

(see fig. 4 for cross-section and fig. 5 for well hydrographs).

The Chicot, Evangeline, and Jasper 

equivalent aquifer systems extend 

across most of southeastern Louisiana 

and generally consist of silt, sand, and 

gravel separated by discontinuous layers 

of clay and sandy clay. The aquifer 

systems dip and thicken to the south 

and contain freshwater to depths of 

greater than 3,500 feet (ft) below the 

National Geodetic Vertical Datum of 

1929 (NGVD 29) (fig. 3). Recharge to 

the aquifers is primarily by precipitation 

in outcrop areas across the northern part 

of the 10-parish area and in southwestern 

Mississippi (Griffith, 2003) (figs. 3, 4). 

Prior to development of the regional 

aquifer system, which began in the 

late 1800s (Harris, 1904), groundwater 

generally flowed from north to south and 

towards the Mississippi and Pearl Rivers 

(Kuniansky, 1989; Martin and Whiteman, 

1989; Halford and Lovelace, 1994). 

Development of the aquifer systems has 

altered the direction of flow in some 

areas, particularly near Baton Rouge, 

where large regional cones of depression 

have formed in the water-level surfaces 
laf17-0800_fig 04

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?

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?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

Norco

aquifer

GonzalesNew Orleans

aquifer Mississippi River

alluvial aquifer

Upland

terrace

aquifer

Catahoula

aquifer

"1,700-foot"

sand

"1,500-foot"

 sand

"1,700-foot" sand

"2,000-foot"

sand "2,400-foot"

sand "2,400-foot"

sand

"2,400-foot"

sand

"2,800-foot"

sand

"1,500-foot"

 sand

"1,000-foot"

 sand

“400-foot" sand

“800-foot" sand

“600-foot" sand

"1,200-foot" sand

"1,500-foot" sand

"1,000-foot"

sand “800-foot"

 sand

“600-

foot" sand

“400-foot" sand

"1,500-foot"

sand

"1,700-foot"

sand

"1,200-foot" sand

"1,500-foot"

sand

"1,000-foot"

sand

"1,700-foot"

sand

"2,400-foot"

sand

"2,800-foot"

sand

"2,000-foot"

sand

"2,400-foot"

sand

"2,800-foot"

sand "2,400-foot"

sand

"1,700-foot" sand

"1,200-foot"

sand

"1,700-foot"

sand

“800-foot" sand

“600-foot" sand

“400-foot" sand

"2,000-foot" sand

"2,800-foot" sand

"2,800-foot" sand

"2,000-foot" sand

"1,500-foot" sand

"1,700-foot" sand

“800-foot" sand

"1,200-foot" sand

"1,000-foot"

sand

NORTH SOUTH BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION BEND IN SECTION

A A'

EXPLANATION

Freshwater in aquifer

Saltwater in aquifer—Saltwater contains greater

 than 250 milligrams per liter chloride

Clay

Lithologic contact—Separates clay and sand units.

 Dashed where approximate. Queried where uncertain

Hydrogeologic contact—Defines boundary 

 between conjoined or merged aquifers

Aquifer system contact

Fault

0 2 4 6 8 10 MILES

0 2 4 6 8 10 KILOMETERS

VERTICAL SCALE GREATLY EXAGGERATED

WEST FELICIANA PARISHEAST FELICIANA PARISHEAST FELICIANA PARISH

EAST BATON ROUGE

PARISH

EAST BATON ROUGE PARISH

IBERVILLE PARISH

IBERVILLE PARISHASCENSION PARISH

BATON ROUGE FAULT

DENHAM SPRINGSSCOTLANDVILLE FAULT

FEET

400

200

NGVD 29

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

2,200

2,400

2,600

2,800

3,000

3,200

FEET

400

200

NGVD 29

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

2,200

2,400

2,600

2,800

3,000

3,200

Chicot equivalent aquifer system

Evangeline equivalent aquifer system

Jasper equivalent aquifer system

Figure 4. Generalized north-to-south hydrogeologic section through the western part of the Southern Hills regional aquifer system, Louisiana 

(modified from Griffith, 2003). Trace of section shown on figure 1.

in wells screened in these aquifer systems. 

A smaller local cone of depression has 

been observed near Bogalusa in the 

Jasper equivalent aquifer system. Cones 

of depression indicate that groundwater 

is moving radially towards the center of 

the cone (Prakken, 2004; Fendick, 2007; 

Tomaszewski, 2011).

Generally, the location of the Baton 

Rouge Fault (fig. 3) coincides with abrupt 

changes in availability of freshwater 

(fig. 4). North of the fault, the base of 

fresh groundwater is consistently present 

in the Jasper equivalent aquifer system, in 

some places to deeper than 3,500 ft below 

NGVD 29. In general, south of the fault, 

the depth of the base of fresh groundwater 

transitions and is restricted to the Chicot 

equivalent aquifer system; however, 

freshwater extends south of the fault 

to a limited distance in the Evangeline 

and Jasper equivalent aquifer systems in 

some areas. Salty groundwater movement 

in East Baton Rouge Parish affects the 

availability of fresh groundwater. Large 

groundwater withdrawals in the Baton 

Rouge area have induced northward 

encroachment of saltwater across the 

Baton Rouge Fault into freshwater areas 

in some locations (Griffith, 2003). 

Water levels and withdrawals vary 

by aquifer system. Water levels remained 

stable in wells screened in the upper part 

of the Chicot equivalent aquifer system 

during 2002–11 (fig. 5A), whereas wells 

screened in the lower part of the Chicot 

equivalent aquifer system declined in 

the western parts of the 10-parish area 

during 1991–2012 (fig. 5B). Water levels 

have generally declined during the last 

20–60 years at monitored wells screened 

in the Evangeline and Jasper equivalent 

aquifer systems because of withdrawals 

(figs. 5C, D). Declines have generally

been the greatest near withdrawal 

centers in and near the Baton Rouge 

metropolitan area. In 2014, withdrawals 

increased with aquifer-system depth: 

Chicot equivalent (40.99 Mgal/d), 

Evangeline equivalent (100.35 Mgal/d), 

and Jasper equivalent (118.8 Mgal/d). 
laf17-0800_fig 05

Year

1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016

Water-level altitude, in feet

-150

-100

-50

0

50

100

150

Well: EB-146 Aquifer: "1,200-foot" sand of the Baton Rouge area

Altitude of land surface: 52 ft above NGVD 29

Well depth: 1,259 ft below land surface

Well: Li-52 Aquifer: "1,700-foot" sand of the Baton Rouge area

Altitude of land surface: 46 ft above NGVD 29

Well depth: 1,865 ft below land surface 

Well: Ta-278 Aquifer: Covington

Altitude of land surface: 52 ft above NGVD 29

Well depth: 1,430 ft below land surface

Well: ST-563 Aquifer: Slidell aquifer

Altitude of land surface: 10 ft above NGVD 29

Well depth: 2,411 feet below land surface 

EXPLANATION

C. Evangeline equivalent aquifer system

1962 1968 1974 1980 1986 1992 1998 2004 2010 2016

-60

-40

-20

0

20

40

60

80

100

Well: WF-222 Aquifer: "2,400-foot" sand of the Baton Rouge area

Altitude of land surface: 140 ft above NGVD 29

Well depth: 1,526 ft below land surface

Well: Ta-268 Aquifer: Hammond

Altitude of land surface: 35 ft above NGVD 29

Well depth: 2,449 ft below land surface

Well: Wa-158 Aquifer: Amite

Altitude of land surface: 97 ft above NGVD 29

Well depth: 1,414 ft below land surface 

Well: Li-185 Aquifer: "2,400-foot" sand of the Baton Rouge area

Altitude of land surface: 37 ft above NGVD 29

Well depth: 2,611 ft below land surface 

Well: EB-1000 Aquifer: "2,800-foot" sand of the Baton Rouge area

Altitude of land surface: 68 ft above NGVD 29

Well depth: 2,926 ft below land surface

Year

D. Jasper equivalent aquifer system

EXPLANATION

Year

1985 1990 1995 2000 2005 2010 2015 2020

0

5

10

15

20

25

30

Well: EB-827 Aquifer: "600-foot" sand of the Baton Rouge area

Altitude of land surface: 64 ft above NGVD 29

Well depth: 370 ft below land surface 

Well: Li-122 Aquifer: "400-foot" sand of the Baton Rouge area

Altitude of land surface: 11 ft above NGVD 29

Well depth: 500 ft below land surface 

EXPLANATION

B. Lower Chicot equivalent aquifer system

1998 2000 2002 2004 2006 2008 2010 2012 2014 2016

Water-level altitude, in feet

60

70

80

90

230

240

250

Well: Ta-362 Aquifer: Upland terrace

Altitude of land surface: 265 ft above NGVD 29

Well depth: 43 ft below land surface

Well: Wa-13 Aquifer: Upland terrace

Altitude of land surface: 95 ft above NGVD 29

Well depth: 156 ft below land surface 

Well: SH-56 Aquifer: Upland terrace

Altitude of land surface: 77 ft above NGVD 29

Well depth: 160 ft below land surface

Year

EXPLANATION

A. Upper Chicot equivalent aquifer system

 Figure 5. Water levels in wells screened in the A, upper part of the Chicot equivalent aquifer system; B, lower part of the Chicot equivalent 

aquifer system; C, Evangeline equivalent aquifer system; and D, Jasper equivalent aquifer system of the Southern Hills regional aquifer 

system, Louisiana (see fig. 3 for well locations; U.S. Geological Survey, 2017). Land surface and water-level altitude are in feet (ft) relative to 

the National Geodetic Vertical Datum of 1929 (NGVD 29).
In addition, 31.99 Mgal/d were 

withdrawn from the Mississippi River 

alluvial aquifer in Pointe Coupee 

(28.05 Mgal/d), West Baton Rouge 

(3.87 Mgal/d), East Baton Rouge 

(0.06 Mgal/d), and West Feliciana 

(0.01 Mgal/d) Parishes (U.S. Geological 

Survey, 2016).

 The Chicot Equivalent Aquifer System

The primary aquifers composing the 

Chicot equivalent aquifer system in the 

western part of the 10-parish area, from 

shallowest to deepest, are the shallow 

sands, Upland terrace aquifer, and the 

“400-foot” and “600-foot” sands of the 

Baton Rouge area (Griffith, 2003; fig. 4). 

In the eastern part of the 10-parish area, 

from shallowest to deepest, the primary 

aquifers are the Upland terrace and upper 

Ponchatoula aquifers. 

In 2016, State well-registration 

records listed 26,358 active water 

wells screened in the Chicot equivalent 

aquifer system in the Southern Hills 

region, including 23,743 domestic, 

1,477 irrigation, 1,006 public supply, 

and 132 industrial. Well depths ranged 

from 10 to 980 ft below land surface, 

and reported yields ranged from 

1 to 3,000 gallons per minute (gal/

min) (data provided by Louisiana 

Department of Natural Resources Office 

of Conservation /Environmental 

Division, 2016). 

The Evangeline Equivalent

Aquifer System

The primary aquifers composing the 

Evangeline equivalent aquifer system, 

from shallowest to deepest, in the 

western part of the 10-parish area are the 

“800-foot,” “1,000-foot,” “1,200-foot,” 

“1,500-foot,” and “1,700-foot” sands of 

the Baton Rouge area (Griffith, 2003; fig. 

4). In the eastern part of the 10-parish 

area, the primary aquifers are the Lower 

Ponchatoula, Big Branch, Kentwood, 

Abita, Covington, and Slidell aquifers. 

In 2016, State well-registration 

records listed 2,552 active water wells 

screened in the Evangeline equivalent 

aquifer system in the Southern Hills 

region, including 428 public supply, 91 

industrial, 1,870 domestic, 156 irrigation, 

and 7 power generation. Well depths 

ranged from 60 to 2,460 ft below land 

surface, and reported yields ranged from 

about 1 to 3,000 gal/min (data provided 

by Louisiana Department of Natural 

Resources Office of Conservation/

Environmental Division, 2016). 

The Jasper Equivalent Aquifer System

The primary aquifers composing the 

Jasper equivalent aquifer system, from 

shallowest to deepest, in the western part 

of the 10-parish area are the “2,000-foot,” 

“2,400-foot,” and “2,800-foot” sands of 

the Baton Rouge area (Griffith, 2003; fig. 

4). In the eastern part of the 10-parish 

area, the primary aquifers are the 

Tchefuncte, Hammond, Amite, Ramsay, 

and Franklinton aquifers. 

In 2016, State well-registration 

records listed 564 active water wells 

screened in the Jasper equivalent 

aquifer system in the Southern Hills 

region, including 329 public supply, 

69 industrial, 130 domestic, 10 power 

generation, and 26 irrigation. Well depths 

ranged from 469 to 3,072 ft below land 

surface. Reported yields from these wells 

ranged from about 5 to 3,400 gal/min 

(data provided by Louisiana Department 

of Natural Resources Office of 

Conservation/Environmental 

Division, 2016). 

Water Quality

Freshwater samples collected from 

1,522 wells screened in the Chicot, 

Evangeline, and Jasper equivalent aquifer 

systems of the Southern Hills regional 

aquifer system indicate that groundwater 

from the aquifer systems is soft2

 and 

does not exceed the U.S. Environmental 

Protection Agency’s Secondary 

Maximum Contaminant Levels (SMCLs)3

for dissolved-solids concentrations. 

Median values for pH and temperature in 

groundwater increase as aquifer-system 

depth increases (table 2). Localized 

concentrations of iron and manganese can 

greatly exceed the SMCLs. 

2

Hardness ranges, expressed as milligrams per 

liter of calcium carbonate, are as follows: 0–60, 

soft; 61–120, moderately hard; 121–180, hard; 

greater than 180, very hard (Hem, 1985). 3

The SMCLs are nonenforceable Federal 

guidelines regarding cosmetic effects (such as tooth 

or skin discoloration), aesthetic effects (such as 

taste, odor, or color), or technical effects (such as 

damage to water equipment or reduced effectiveness 

of treatment for other contaminants) of drinking 

water. SMCLs were established as guidelines by the 

U.S. Environmental Protection Agency (2016).

References Cited 

Buono, A., 1983, The Southern Hills regional 

aquifer system of southeastern Louisiana and 

southwestern Mississippi: U.S. Geological 

Survey Water-Resources Investigations 

Report 83–4189, 43 p. [Also available 

at https://pubs.er.usgs.gov/publication/

wri834189.]

Fendick, R.B., Jr., 2007, Louisiana 

ground-water map no. 22—Generalized 

potentiometric surface of the Amite aquifer 

and “2,800-foot” sand of the Baton Rouge 

area in southeastern Louisiana, June–August 

2006: U.S. Geological Survey Scientific 

Investigations Map 2984, 1 sheet, accessed 

March 2, 2012, at http://pubs.usgs.gov/

sim/2984/.

Griffith, J.M., 2003, Hydrogeologic framework 

of southeastern Louisiana: Louisiana 

Department of Transportation and 

Development Water Resources Technical 

Report no. 72, 21 p., 18 pls. 

Halford, K.J., and Lovelace, J.K., 1994, 

Analysis of ground-water flow in the “1,200-

foot” aquifer, Baton Rouge area, Louisiana: 

Louisiana Department of Transportation and 

Development Water Resources Technical 

Report no. 54, 68 p.

Harris, G.D., 1904, Underground waters of 

southern Louisiana, with discussions of 

their uses for water supplies and for rice 

irrigation, by M.L. Fuller: U.S. Geological 

Survey Water-Supply Paper 101, 98 p.

Hem, J.D., 1985, Study and interpretation 

of the chemical characteristics of natural 

water (3d ed.): U.S. Geological Survey 

Water-Supply Paper 2254, 264 p., accessed 

February 20, 2013, at http://pubs.er.usgs.

gov/publication/wsp2254.

Kuniansky, E.L., 1989, Geohydrology and 

simulation of ground-water flow in the 

“400-foot,” “600-foot,” and adjacent 

aquifers, Baton Rouge area, Louisiana: 

Louisiana Department of Transportation and 

Development Water Resources Technical 

Report no. 49, 90 p.

Martin, Angel, Jr., and Whiteman, C.D., Jr., 

1989, Geohydrology and regional groundwater flow of the coastal lowlands aquifer 

system in parts of Louisiana, Mississippi, 

Alabama, and Florida—A preliminary 

analysis: U.S. Geological Survey WaterResources Investigations Report 88–4100, 

88 p.

Prakken, L.B., 2004, Louisiana ground-water 

map no. 17—Generalized potentiometric 

surface of the Kentwood aquifer system and 

the “1,500-foot” and “1,700-foot” sands 

of the Baton Rouge area in southeastern 

Louisiana, March–April 2003: U.S. 

Geological Survey Scientific Investigations 

Map 2862, 2 sheets, accessed February 24, 

2012, at http://pubs.er.usgs.gov/publication/

sim2862.
Table 2. Summary of selected water-quality characteristics for 1,522 wells screened in the Chicot, Evangeline, and Jasper equivalent aquifer 

systems in the 10 parishes overlying the Southern Hills regional aquifer system (U.S. Geological Survey, 2017).

[Values are in milligrams per liter, except as noted. °C, degree Celsius; SU, standard unit; CaCO3, calcium carbonate; μg/L, microgram per liter; <, less than; SMCL, 

Secondary Maximum Contaminant Level established by the U.S. Environmental Protection Agency (2016); NA, not applicable]

Temperature 

(°C)

pH, field 

(SU)

Hardness

(as CaCO3

)

Chloride,

filtered (as Cl)

Iron, filtered, 

μg/L (as Fe)

Manganese, 

filtered, μg/L 

(as Mn)

Dissolved

solids, filtered

Chicot equivalent aquifer system (1939–2015; 476 wells)

Median 22.5 7.1 22 11 100 50 194

10th percentile 20 5.2 6 3.1 <4 <0.8 48

90th percentile 24.5 8.2 98.8 120 1,100 311 418.8

Number of samples 625 402 813 1,516 197 204 230

Percentage of samples that 

do not exceed SMCLs NA 65 NA NA 71 50 95

Evangeline equivalent aquifer system (1936–2015; 544 wells)

Median 28 7.9 5 4.4 70 20.5 198

10th percentile 22.5 6.5 1 2.3 <10 <10 110

90th percentile 32.1 8.9 25 100 1,200 183 260.4

Number of samples 987 546 1,165 2,005 259 208 397

Percentage of samples that 

do not exceed SMCLs NA 63 NA 100 76 64 99

Jasper equivalent aquifer system (1939–2014; 502 wells)

Median 31.2 8.3 4 4.1 90 20 213

10th percentile 24 7 1 1.6 <10 <5.0 160.8

90th percentile 36 9 20 140 1,300 199 391.6

Number of samples 905 647 1,101 1,893 342 242 459

Percentage of samples that 

do not exceed SMCLs NA 57 NA 100 74 67 95

SMCLs

NA 6.5–8.5 NA 250 300 50 500

Sargent, B.P., 2011, Water use in Louisiana, 

2010: Louisiana Department of 

Transportation and Development Water 

Resources Special Report no. 17, 135 p. 

Smoot, C.W., 1988, Louisiana hydrologic 

atlas map no. 3—Altitude of the base of 

freshwater in Louisiana: U.S. Geological 

Survey Water-Resources Investigations 

Report 86–4314, 1 sheet, accessed 

November 2, 2011, at http://pubs.er.usgs.

gov/publication/wri864314.

Tomaszewski, D.J., 2011, Water-level surface 

in the Chicot equivalent aquifer system 

in southeastern Louisiana, 2009: U.S. 

Geological Survey Scientific Investigations 

Map 3173, 2 pls., accessed February 24, 

2012, at http://pubs.usgs.gov/sim/3173/.

U.S. Environmental Protection Agency, 2016, 

Secondary Drinking Water Standards: 

Guidance for Nuisance Chemicals, accessed 

April 13, 2016, at https://www.epa.gov/

dwstandardsregulations/secondary-drinkingwater-standards-guidance-nuisancechemicals. 

U.S. Geological Survey, 2016, U.S. Geological 

Survey Water Resources Cooperative 

Program: Louisiana Water Use Program, 

accessed October 17, 2016, at http://la.water.

usgs.gov/WaterUse/default.asp.

U.S. Geological Survey, 2017, National Water 

Information System—Web Interface: 

U.S. Geological Survey Web page, 

accessed February 1, 2017, at http://dx.doi.

org/10.5066/F7P55KJN.

This fact sheet was published by the

U.S. Geological Survey in cooperation with 

the Louisiana Department of Transportation 

and Development.

By Vincent E. White

For additional information, contact: 

Director, USGS Lower Mississippi-Gulf 

Water Science Center

3535 S. Sherwood Forest Blvd., Suite 120

Baton Rouge, LA 70816

E-mail: gs-w-lmg_center_director@usgs.gov

Fax: (225) 298–5490

Telephone: (225) 298–5481

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