U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3064

June 2012

Prepared in cooperation with the Louisiana Department of Transportation and Development 

Water Resources of Allen Parish

D O TD

APED TR MENT OF TRANSPORTATION AND DEVELOPMENT

A'

A

ALLEN 

PARISH

RAPIDES

PARISH

EVANGELINE

PARISH

J

Kinder

Oberlin

Reeves

Oakdale

Elton

Basile

Fenton

Iota

Glenmora

Longleaf

DeRidder

Rosepine

Al-241

Al-269

93 ̊15' 93 ̊00' 92 ̊45'

30 ̊45'

30 ̊30'

30 ̊15'

Elizabeth

92 ̊30'

Whisky

Creek

Chitto

Sixmile Creek

Tenmile

Creek

Mill

Creek

River

Calcasieu

River

Calcasieu

Blue

Bayou

VERNON

PARISH

BEAUREGARD

PARISH

EFFERSON

DAVIS

PARISH

ACADIA

PARISH

L O U I S I A N A

A R K A N S A S

M I S

S I S

S I P

P

T

I

E X A S

G U L F O F M E X I C O

ENLARGED

AREA

10 KILOMETERS

0

0

10 MILES

Base map modified from Louisiana Department of Transportation and Development (1986)

EXPLANATION

1,000 to 1,499

1,500 to 1,999

Approximate altitude of the base of 

 fresh groundwater, in feet below 

 National Geodetic Vertical Datum of 

 1929 (Smoot, 1988) 

2,000 to 2,499

2,500 to 3,500

 Some intermediate sands 

 contain saltwater

Al-241 Well for which hydrograph

 is shown (see fig. 4)

Discharge site on Bayou Blue

near Elton, La. 

Trace of hydrogeologic 

 section (see fig. 3)

Water-quality site on Calcasieu

River near Kinder, La.

(see table 4) 

A A'

165

190

190

165

165

10

10

10

112

112

112

26

26

26

372

383

104

377

113

377

Introduction 

In 2005, approximately 29.2 million gallons per day 

(Mgal/d) of water were withdrawn in Allen Parish, Louisiana 

(fig. 1), including about 26.8 Mgal/d from groundwater sources 

and 2.45 Mgal/d from surface-water sources1 (table 1). Rice 

irrigation accounted for 74 percent (21.7 Mgal/d) of the total 

water withdrawn. Other categories of use included public 

supply, industrial, rural domestic, livestock, general irrigation, 

1

Tabulation of numbers across text and tables may result in different totals 

because of rounding; nonrounded numbers are used for calculation of totals. 

and aquaculture (table 2). Water-use data collected at 5-year 

intervals from 1960 to 2005 indicate water withdrawals 

in the parish were greatest in 1960 (119 Mgal/d) and 1980 

(98.7 Mgal/d) (fig. 2). The substantial decrease in surface-water 

use between 1960 and 1965 is primarily attributable to riceirrigation withdrawals declining from 61.2 to 6.74 Mgal/d. 

This fact sheet summarizes information on the 

water resources of Allen Parish, Louisiana. Information 

on groundwater and surface-water availability, quality, 

development, use, and trends is based on previously published 

reports listed in the Selected References section. 

Figure 1. Location of study area, Allen Parish, Louisiana.
Groundwater Resources 

The primary groundwater resources of Allen Parish, 

from near surface to deepest, include the Chicot aquifer 

system, Evangeline aquifer, and Jasper aquifer system (fig. 3). 

The Chicot aquifer system and Evangeline aquifer contain 

freshwater throughout the parish. The Jasper aquifer system 

contains freshwater in the northwestern half of the parish and 

saltwater (water with chloride concentrations greater than 

250 milligrams per liter [mg/L]) in the southeastern half. 

The base of fresh groundwater generally ranges from about 

1,500 to 3,500 feet (ft) below the National Geodetic Vertical 

Datum of 1929 (NGVD 29) (sea level) in the northwestern half 

of the parish and from about 1,500 to 2,200 ft below NGVD 29 

in the southeastern half of the parish (fig. 1). 

Recharge to aquifers in the parish is from rainfall, leakage 

from overlying aquifers, and seasonally from rivers. Discharge 

from the aquifers is by natural flow into rivers, leakage into 

underlying aquifers, and withdrawals from wells. 

Table 1. Water withdrawals, in million gallons per day, by source 

in Allen Parish, Louisiana, 2005 (modified from Sargent, 2007).

Aquifer, aquifer system, or 

surface-water body Groundwater Surface water

Chicot aquifer system 23.07

Evangeline aquifer 3.68

Bayou Blue .33

Calcasieu River 2.10

Miscellaneous streams .02

Total 26.75 2.45

Table 2. Water withdrawals, in million gallons per day, by 

category in Allen Parish, Louisiana, 2005 (modified from Sargent, 

2007).

Category Groundwater

Surface 

water Total

Public supply 3.71 0.00 3.71

Industrial .07 .00 .07

Rural domestic .25 .00 .25

Livestock .06 .02 .08

Rice irrigation 19.51 2.23 21.74

General irrigation .20 .00 .20

Aquaculture 2.95 .21 3.15

Total 26.75 2.45 29.20

0

10

20

30

40

50

60

70

80

90

100

110

120

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Annual withdrawal, in million gallons per day

Year

Groundwater

Surface water

EXPLANATION

Figure 2. Water withdrawals in Allen Parish, Louisiana, 1960–2005.

A A’

Chicot

aquifer

systemJasper aquifer system

Castor Creek

confining unit

Dough Hills

confining unit

Williamson

Creek

aquifer

Carnahan

bayou

aquifer

NGVD 29

FEET

Vertical datum is National Geodetic Vertical Datum of 1929 (NGVD 29)

VERTICAL SCALE GREATLY EXAGGERATED

EXPLANATION

Contacts dashed where inferred

Base of freshwater

Evangeline

-500 aquifer

-1,500

-2,000

-2,500

-3,000

-3,500

-1,000

NGVD 29

FEET

-500

-1,500

-2,000

-2,500

-3,000

-3,500

-1,000

0 4 MILES

4 KILOMETERS

Calcasieu

River

Undifferentiated sand

Surficial

confining unit

Shallow sand

(Individual sand and clay

layers not shown)

(Individual sand and clay

layers not shown)

NORTH SOUTH

Base

of

freshwater

Figure 3. Generalized north-to-south hydrogeologic section 

through Allen Parish, Louisiana, showing aquifer and confining unit 

intervals (modified from Whitfield, 1975, pl. 4). Trace of section is 

shown on figure 1.
State well-registration records listed 621 active water wells 

in Allen Parish in 2010, including 355 domestic, 211 irrigation, 

42 public-supply, and 13 industrial wells. In 2005, groundwater 

withdrawals for various uses included public supply, industrial, 

rural domestic, livestock, rice irrigation, general irrigation, and 

aquaculture (table 2). 

Chicot Aquifer System 

In Allen Parish, the Chicot aquifer system consists of the 

shallow sand and the deeper undifferentiated sand. The shallow 

sand is present as scattered sand streaks, lenses, and beds within a 

surficial clay confining unit (fig. 3). The confining unit generally 

ranges in thickness from 40 to 80 ft and is less than 40 ft in 

some areas of the parish. State well-registration records listed 

75 active water wells screened in the shallow sand in Allen Parish 

in 2010, including 71 domestic, 2 irrigation, and 2 public-supply 

wells. Depths of these wells ranged from 13 to 100 ft below land 

surface, with a median depth of 32 ft. In 2005, water withdrawals 

from the shallow sand of the Chicot aquifer system in Allen 

Parish totaled about 0.09 Mgal/d. 

The undifferentiated sand is present throughout Allen Parish 

and is the primary component of the Chicot aquifer system within 

the parish. It typically underlies the surficial confining unit and is 

composed of beds of clay, silt, sand, and gravel. Individual beds 

of sand are usually massive and can attain thickness of several 

hundred feet. Individual sand beds usually contain fine sand 

at the top and grade to coarse sand and gravel at the base. The 

undifferentiated sand dips and thickens towards the south and 

southeast. The altitude of the base of the undifferentiated sand 

ranges from about 0 ft NGVD 29 near the northern parish line to 

about 400–500 ft below NGVD 29 along the southern parish line. 

Infiltration of precipitation in southern Vernon and Rapides 

Parishes, northern Beauregard Parish, and northern Allen Parish 

is the primary source of recharge to the Chicot aquifer system in 

Allen Parish. Vertical leakage through clays is a secondary source. 

In 2003, water levels in the undifferentiated sand in Allen 

Parish ranged from about 120 ft above NGVD 29 near the 

Allen-Vernon Parish line to nearly 40 ft below NGVD 29 in 

the southeastern corner of the parish. Water movement in the 

undifferentiated sand in Allen Parish generally is to the south 

or southeast. Water levels in the undifferentiated sand generally 

fluctuate 5 ft or more because of seasonal withdrawals, as shown in 

the hydrograph of well Al-241 (fig. 4), located northwest of Kinder 

in southern Allen Parish (fig. 1). 

State well-registration records listed 443 active water 

wells screened in the undifferentiated sand in Allen Parish in 

2010, including 238 domestic, 190 irrigation, 12 public-supply, 

and 3 industrial wells. Depths of these wells ranged from 

16 to 450 ft below land surface, with a median depth of 130 ft. 

Reported yields from wells screened in the undifferentiated sand 

in Allen Parish ranged from less than 10 to 7,000 gallons per 

minute (gal/min). 

In 2005, withdrawals from the undifferentiated sand of the 

Chicot aquifer system in Allen Parish were about 23.0 Mgal/d 

and included about 0.10 Mgal/d for public supply, 0.21 Mgal/d 

for rural domestic use, 0.02 Mgal/d for livestock, 19.5 Mgal/d 

for rice irrigation, 0.20 Mgal/d for general irrigation, and 

2.95 Mgal/d for aquaculture. 

A statistical summary of selected water-quality characteristics 

for 81 wells screened in the undifferentiated sand in Allen Parish 

is listed in table 3. Generally, water from the undifferentiated 

sand is soft (60 mg/L or less as calcium carbonate) and does 

not exceed the U.S. Environmental Protection Agency’s (EPA) 

Year

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

Water level, in feet above or below

National Geodetic Vertical Datum of 1929 (NGVD 29)

-15

-10

-5

0

5

10

15

20

25

Well: Al-241

Altitude of land surface: 42.97 ft above NGVD 29

Well depth: 62 ft below land surface

Well: Al-269

Altitude of land surface: 45 ft above NGVD 29

Well depth: 660 ft below land surface

Figure 4. Water levels 

in well AI-241 screened in 

the Chicot aquifer system 

(undifferentiated sand) and 

well AI-269 screened in the 

Evangeline aquifer in Allen 

Parish, Louisiana (see fig. 

1 for well locations; U.S. 

Geological Survey, 2012a). 

Land surface is measured 

in feet above the National 

Geodetic Vertical Datum of 

1929 (NGVD 29).
Secondary Maximum Contaminant Levels (SMCLs)2

 for 

drinking water for color or for concentrations of chloride, iron, 

and dissolved solids. Locally, iron concentrations can exceed 

the SMCL of 300 micrograms per liter (μg/L). Manganese 

concentrations are generally greater than the SMCL of 

50 μg/L. The median pH value of 6.2 is below the SMCL 

range of 6.5–8.5. 

Evangeline Aquifer 

The Evangeline aquifer is present throughout Allen Parish 

and underlies the Chicot aquifer system (fig. 3). It consists 

primarily of fine to medium sand interbedded with silt, soft to 

moderately hard green-gray laminated clay, and local beds of 

coarse sand. Locally, sands within the aquifer are separated 

and confined by extensive clays. The altitude of the top of the 

aquifer is equivalent to the base of the Chicot aquifer system 

and is about 0 ft NGVD 29 near the northern parish line and 

about 400–500 ft below NGVD 29 near the southern parish 

2

The SMCLs are nonenforceable Federal guidelines regarding cosmetic 

effects (such as tooth or skin discoloration) or aesthetic effects (such as 

taste, odor, or color) of drinking water. At high concentrations or values, 

health implications as well aesthetic degradation might exist. SMCLs 

were established as guidelines for the states by the U.S. Environmental 

Protection Agency (1992). 

line. The approximate thickness of the Evangeline aquifer in 

Allen Parish ranges from 900 ft near the northern parish line to 

2,000 ft near the southern parish line. The aggregate thickness 

of freshwater sands in the aquifer ranges from about 200 ft near 

the southern parish line to about 1,000 ft in the western-central 

area of the parish. Near the town of Elizabeth, aggregate 

freshwater sand thickness is about 400 ft. 

In 2003, water levels in the aquifer generally ranged from 

about 140 ft above NGVD 29 in the northwestern corner of 

the parish to about 40 ft below NGVD 29 in its southeastern 

corner. Water levels at well Al-269, located northeast of the 

town of Kinder in southern Allen Parish (fig. 1), have generally 

ranged between 5 and 10 ft below NGVD 29 since 1993 (fig. 4). 

Water movement in the Evangeline aquifer in Allen Parish is 

generally towards the south-southeast. 

State well-registration records listed 34 active water 

wells screened in the Evangeline aquifer in Allen Parish in 

2010, including 25 for public supply, 8 for industrial use, 

and 1 for domestic use. Depths of these wells ranged from 

390 to 1,720 ft below land surface with a median depth 

of 749 ft. Yields from wells screened in the Evangeline 

aquifer in Allen Parish reportedly range from about 9 to 

1,000 gal/min. In 2005, withdrawals from the Evangeline 

aquifer in Allen Parish were about 3.68 Mgal/d (table 1) and 

included about 3.61 Mgal/d for public supply and 0.07 Mgal/d 

for industrial use. 

Table 3. Summary of selected water-quality characteristics of freshwater in the Chicot aquifer system (undifferentiated sand) and 

Evangeline aquifer in Allen Parish, Louisiana (U.S. Geological Survey, 2012b).

[Values are in milligrams per liter, except as noted. oC, degrees Celsius; PCU, platinum cobalt units; μS/cm, microsiemens per centimeter; SU, standard units; 

CaCO3, calcium carbonate; μg/L, micrograms per liter; <, less than; NA, not applicable; SMCL, Secondary Maximum Contaminant Level established by the 

U.S. Environmental Protection Agency (2011)]

Temperature (°C)Color,

(PCU)

Specific

conductance,

field

(μS/cm at 

25°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 aquifer system (undifferentiated sand), 1940–2008 (81 wells) 

Median 20.7 5 151 6.2 30 18 200 55 120

10th percentile 20.0 0 62 5.3 6 5.5 <10 <1 46

90th percentile 21.5 28 271 7.9 73 32 6,700 540 206

Number of samples 51 13 55 44 59 80 31 28 40

Percentage of samples 

that do not exceed 

SMCLs

NA 77 NA 41 NA 100 55 50 100

Evangeline aquifer, 1946–95 (44 wells) 

Median 23.5 10 321 8.2 5 8.0 230 20 230

10th percentile 21.5 5 255 7.2 2 4.8 50 0 193

90th percentile 25.0 140 764 8.6 26 25 870 76 494

Number of samples 33 41 42 43 43 44 41 33 40

Percentage of samples 

that do not exceed 

SMCLs

NA 59 NA 84 NA 100 61 85 90

SMCLs

NA 15 NA 6.5–8.5 NA 250 300 50 500
A statistical summary of selected water-quality 

characteristics for 44 wells screened in the Evangeline aquifer 

in Allen Parish is listed in table 3. Generally, water from the 

Evangeline aquifer is soft and does not exceed the SMCLs 

for drinking water for color and pH or for concentrations 

of chloride, iron, manganese, and dissolved solids. Locally, 

color and concentrations of iron and manganese may exceed 

their SMCLs. 

Jasper Aquifer System 

The Jasper aquifer system underlies all of Allen Parish 

and consists of the Williamson Creek aquifer, Dough Hills 

confining unit, and Carnahan Bayou aquifer (fig. 3). The 

clayey Castor Creek confining unit separates the Jasper aquifer 

system from the overlying Evangeline aquifer. The aquifer 

system contains freshwater in the northern and western parts 

of the parish. Freshwater is present in all the sands of the 

aquifer system only in the extreme northwest corner of the 

parish. Toward the southeast, the base of freshwater becomes 

progressively shallower (fig. 3), and the number of freshwaterbearing sands and the aggregate thickness of freshwater sands 

decrease proportionately. Light-gray sands with occasional 

traces of granule-size gravel make up approximately 50 percent 

of the aquifers within the system. The predominantly 

sandy Williamson Creek and Carnahan Bayou aquifers are 

composed of generally well-sorted, very fine to medium sands 

interbedded with greenish-gray clays. 

Thickness of the Jasper aquifer system in Allen Parish 

generally ranges from about 2,500 ft near the town of Elizabeth 

to over 3,500 ft near the town of Oberlin (fig. 1). The altitude of 

the top of the aquifer is about 1,300 ft below NGVD 29 near the 

northern parish line and about 3,000 ft below NGVD 29 near 

the southern parish line. 

State well-registration records did not list any active water 

wells screened in the Jasper aquifer system in Allen Parish in 

2010. Data from test holes drilled into freshwater areas of the 

Williamson Creek aquifer in Allen Parish indicate the water is 

soft, with a pH above 8.0. Iron concentrations generally exceed 

the SMCL of 300 μg/L. 

Surface-Water Resources 

In 2005, about 2.45 Mgal/d of surface water were 

withdrawn in Allen Parish, including about 2.23 Mgal/d for 

rice irrigation, 0.21 Mgal/d for aquaculture, and 0.02 Mgal/d 

for livestock (table 2). About 2.10 Mgal/d were withdrawn 

from the Calcasieu River, and 0.33 Mgal/d were withdrawn 

from Bayou Blue (table 1). Other notable streams and potential 

sources of freshwater in the parish include Whisky Chitto, 

Sixmile, Tenmile, and Mill Creeks (fig. 1). 

The mean discharge for the Calcasieu River near Kinder 

(station number 08015500; U.S. Geological Survey, 2008) from 

1923 to 2008 was 2,620 cubic feet per second (1,690 Mgal/d). 

The drainage area for this site is about 1,700 square miles (mi2). 

Water samples analyzed during the period 1966–98 indicate 

water in the Calcasieu River near Kinder (fig. 1) is generally 

soft (table 4) and does not exceed the SMCLs for drinking 

water concentrations of chloride and sulfate. The pH is 

generally below the SMCL of 6.5 to 8.5 standard units, and iron 

concentrations can exceed the SMCL of 300 μg/L. Dissolved 

oxygen is generally greater than 5 mg/L, which is considered 

the minimum value for a diversified population of fresh, warmwater biota, including sport fish (Louisiana Department of 

Environmental Quality, 2008). 

The drainage area for Bayou Blue at Louisiana Highway 

26 near Elton (station number 303209092401800; U.S. 

Geological Survey, 2012c) (fig. 1) is about 94 mi2. No discharge 

data and few water-quality data are available for the bayou. 

Table 4. Summary of selected water-quality characteristics for the Calcasieu River in Allen Parish, Louisiana, 1966–98.

[Values are in milligrams per liter, except as noted.oC, degrees Celsius; μS/cm, microsiemens per centimeter; SU, standard units; μg/L, micrograms per liter; 

CaCO3, calcium carbonate; <, less than; NA, not applicable; SMCL, Secondary Maximum Contaminant Level established by the U.S. Environmental Protection

Agency (2011)]

Specific

conductance,

field (μS/cm 

at 25oC)

Oxygen, 

dissolvedpH, field

(SU)

Hardness

(as 

CaCO3)

Calcium, 

filtered

(as Ca)

Magnesium, 

filtered

(as Mg)

Sodium, 

filtered

(as Na)

Chloride, 

filtered

(as Cl)

Sulfate, 

filtered

(as SO4)

Iron, 

filtered

(μg/L

as Fe)

Calcasieu River near Kinder, Louisiana1

Median 56 8.4 6.4 11 2.8 0.9 5.3 5.4 4.0 260

10th percentile 32 6.9 5.7 7 1.9 0.5 2.6 3.2 2.0 130

90th percentile 82 10.3 7.1 14 3.6 1.2 12 7.4 8.3 420

Number of samples 110 98 110 110 110 110 105 109 105 64

Percentage of 

samples that 

do not exceed 

SMCLs

NA NA 46 NA NA NA NA 100 100 64

SMCLs 

NA NA 6.5–8.5 NA NA NA NA 250 250 300 1

Station number 08015500 (U.S. Geological Survey, 2012b; specific data at http://nwis.waterdata.usgs.gov/la/nwis/qwdata/?site_no=08015500).
U.S. Geological Survey, 2008, Annual water data reports—Waterdata report 2008 [data for USGS 08015500 Calcasieu River near 

Kinder, LA]: U.S. Geological Survey Water Resources of the 

United States, accessed November 6, 2009, at http://wdr.water.usgs.

gov/wy2008/pdfs/08015500.2008.pdf.

U.S. Geological Survey, 2012a, Ground-water levels for Louisiana: 

National Water Information System Web Interface, accessed 

November 18, 2011, at http://nwis.waterdata.usgs.gov/la/nwis/

gwlevel/. 

U.S. Geological Survey, 2012b, Water quality samples for Louisiana: 

National Water Information System Web Interface, accessed 

February 18, 2009, at http://nwis.waterdata.usgs.gov/la/nwis/

qwdata/.

U.S. Geological Survey, 2012c, U.S. Geological Survey water data 

for Louisiana [for site 303209092401800 Bayou Blue at LA-Hwy 

26 near Elton, LA.]: National Water Information System Web 

Interface, accessed January 5, 2010, at http://nwis.waterdata.usgs.

gov/la/nwis/nwisman/?site_no=303209092401800. 

Whitfield, M.S., Jr., 1975, Geohydrology of the Evangeline and Jasper 

aquifers of southwestern Louisiana: Department of Conservation, 

Louisiana Geological Survey, and Louisiana Department of Public 

Works Water Resources Bulletin no. 20, 72 p. 

By Lawrence B. Prakken , Jason M. Griffith, and

Robert B. Fendick, Jr

For additional information, contact: 

Director, USGS Louisiana Water Science Center

3535 S. Sherwood Forest Blvd., Suite 120

Baton Rouge, LA 70816

E-mail: dc_la@usgs.gov

Fax: (225) 298-5490

Telephone: (225) 298-5481

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

This fact sheet was published by the U.S. 

Geological Survey, in cooperation with the Louisiana 

Department of Transportation and Development 

(DOTD). Thanks are given to Zahir “Bo” Bolourchi, 

Director, Water Resources Programs, Louisiana 

Department of Transportation and Development, who 

contributed to the content and design of the fact sheet.

Selected References 

Fendick, R.B., Jr., 2005, Louisiana ground-water map no. 21—

Generalized potentiometric surface of the Evangeline aquifer in 

south-central Louisiana, 2004: U.S. Geological Survey Scientific 

Investigations Map 2880, 1 sheet, accessed January 5, 2010, at 

http://pubs.usgs.gov/sim/2880/plate-1.pdf.

Harder, A.H., Kilburn, Chabot, Whitman, H.M., and Rogers, S.M., 

1967, Effects of ground-water withdrawals on water levels and 

saltwater encroachment in southwestern Louisiana: Department 

of Conservation, Louisiana Geological Survey, and Louisiana 

Department of Public Works Water Resources Bulletin no. 10, 56 p. 

Louisiana Department of Environmental Quality, 2008, 

Environmental Regulatory Code, Title 33, Part IX, Subpart 1: 

Baton Rouge, Louisiana Department of Environmental Quality, 

accessed June 9, 2009, at http:www.deq.louisiana.gov/portal/

tabid/1674/Default.aspx. 

Louisiana Department of Transportation and Development, 1986, 

Official map of Louisiana—1986 edition: Baton Rouge, Louisiana 

Department of Transportation and Development, 1 sheet. 

Lovelace, J.K., Fontenot, J.W., and Frederick, C.P., 2004, 

Withdrawals, water levels, and specific conductance in the 

Chicot aquifer system in southwestern Louisiana, 2000–03: 

U.S. Geological Survey Scientific Investigations Report 2004-

5212, 56 p. 

Nyman, D.J., 1989, Quality of water in freshwater aquifers in 

southwestern Louisiana: Louisiana Department of Transportation 

and Development Water Resources Technical Report no. 42, 

22 p., 28 pls. 

Sargent, B.P., 2004, Thickness of the Chicot aquifer system surficial 

confining unit and location of shallow sands, southwestern 

Louisiana: Louisiana Department of Transportation and 

Development Water Resources Technical Report no. 73, 29 p. 

Sargent, B.P., 2007, Water use in Louisiana, 2005: Louisiana 

Department of Transportation and Development Water Resources 

Special Report no. 16, 133 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.usgs.gov/wri/1986/4314/

plate-1.pdf. 

U.S. Environmental Protection Agency, 1992, Secondary Drinking 

Water Regulations—Guidance for nuisance chemicals: U.S. 

Environmental Protection Agency publication EPA 810/K-92-001, 

4 p., accessed July 29, 2009, at http://www.epa.gov/safewater/

consumer/2ndstandards.html. 

U.S. Environmental Protection Agency, 2011, 2011 Edition of 

the drinking water standards and health advisories: U.S. 

Environmental Protection Agency, Office of Water, EPA 820-R11-002, 12 p., accessed September 2, 2011, at http://water.epa.gov/

action/advisories/drinking/upload/dwstandards2011.pdf.