U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2016–3047

July 2016

Prepared in cooperation with the Louisiana Department of Transportation and Development 

Water Resources of St. Helena Parish, Louisiana

Introduction

Information concerning the availability, use, and quality 

of water in St. Helena Parish, Louisiana (fig. 1), is critical 

for proper water-resource management. The purpose of this 

fact sheet is to present information that can be used by water 

managers, parish residents, and others for stewardship of this 

vital resource. Information on the availability, past and current 

use, use trends, and water quality from groundwater and 

surface-water sources in the parish is presented. Previously 

published reports (see References Cited section) and data stored 

in the U.S. Geological Survey’s National Water Information 

System (http://waterdata.usgs.gov/nwis) are the primary sources 

of the information presented here. 

In 2010, about 1.06 million gallons per day (Mgal/d) of 

water were withdrawn in St. Helena Parish, including about 

1.05 Mgal/d from groundwater sources and 0.01 Mgal/d from 

surface-water sources1

 (table 1). Withdrawals for rural-domestic 

use accounted for about 50 percent (0.53 Mgal/d) of the total 

water withdrawn (table 2). Other categories of use included 

public supply, industrial, and livestock. Water-use data collected 

at 5-year intervals from 1960 to 2010 indicated that water 

withdrawals peaked in 1960, dropped to less than 1.00 Mgal/d 

in 1965 and 1975, and have remained between 1.00 and 

1.50 Mgal/d since 1980 (fig. 2). 

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 across text and tables may result in different totals because of 

rounding; nonrounded numbers are used for calculation of totals.

38

10

GULF OF MEXICO ST HELENA

PARISH

TEXAS

ARKANSAS MISSISSIPPI

LOUISIANA

0 10 MILES

0 10 KILOMETERS

Base modified from U.S. Geological Survey digital data

Albers Equal-Area Conic projection

North American Datum of 1983

EXPLANATION

Approximate altitude of base of fresh

 groundwater, in feet below National 

 Geodetic Vertical Datum of 1929 

 (modified from Smoot, 1988)—Deepest 

 freshwater contained within the Jasper

 equivalent aquifer system

 2,000 to 2,499

 2,500 to 2,999

Line of section (see fig. 3)

River subbasin boundary

Well for which hydrograph is shown

 (see fig. 4)

U.S. Geological Survey surface-water

 discharge site and number

U.S. Geological Survey surface-water

 quality site and number (see table 4)

SH-56

A'A

07375800

07377000

Tickfaw subbasin

Tangipahoa

subbasin

Amite subbasin

LIVINGSTON

PARISH

ST HELENA

PARISH

EAST

BATON ROUGE

PARISH

EAST

FELICIANA

PARISH

TANGIPAHOA

 PARISH

90°30'

90°40' 90°50'

31°00'

30°50'

30°40'

91°00'

Greensburg

Montpelier

Darlington

Liverpool

A

A'

SH-116

SH-56

07377000

07375800

Amite River

Tickfaw

River

Twelvemile Creek

West Hog

Branch

East Hog

Branch

Darling

Creek

Beaver Creek

Little Natalbany

River

East Fork Amite River

Sandy Run

Buck Creek

Black

Creek

Channey Creek

Joseph Branch

Natalbany 

River

Tangipahoa River

LOUISIANA

MISSISSIPPI

Figure 1. Location of study area, St. Helena Parish, Louisiana.
Table 1. Water withdrawals, in million gallons per day, by source 

in St. Helena Parish, Louisiana, 2010 (Sargent, 2011).

Aquifer, aquifer system, or 

surface-water body Groundwater Surface water

Upland terrace aquifer 0.70

Evangeline equivalent aquifer system0.00

Jasper equivalent aquifer 

system

0.35

Catahoula aquifer 0.00

Miscellaneous streams 0.01

Total 1.05 0.01

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

category in St. Helena Parish, Louisiana, 2010 (modified from 

Sargent, 2011).

Use category Groundwater Surface water Total

Public supply 0.39 0.00 0.39

Industrial 0.03 0.00 0.03

Rural domestic 0.53 0.00 0.53

Livestock 0.09 0.01 0.11

Total 1.05 0.01 1.06

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Annual withdrawal, in million gallons per day

0.00

0.25

0.50

0.75

1.00

1.25

1.50

Groundwater

Surface water

EXPLANATION

Figure 2. Water withdrawals in St. Helena Parish, Louisiana, 

1960–2010 (Sargent, 2011).

Groundwater Resources

Primary sources of fresh groundwater (water with a 

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

less) in St. Helena Parish are, from shallowest to deepest, the 

Chicot equivalent, Evangeline equivalent, and Jasper equivalent 

aquifer systems and the Catahoula aquifer (fig. 3). Deeper 

aquifers underlying the parish contain saltwater. The base of 

fresh groundwater ranges from greater than 2,000 feet (ft) below 

the National Geodetic Vertical Datum of 1929 (NGVD 29) in 

Catahoula

aquifer

“2,800-foot”

sand

“2,400-foot” sand

“2,000-foot”

sand

“1,700-foot” sand

“1,500-foot” sand

“1,200-foot” sand

“1,000-foot” sand “800-foot” sand

Generalized surface profile

?

?

?

?

?

?

?

?

Kentwood

aquifer

Lower

Ponchatoula

aquifer “800-foot” sand

“1,000-foot” sand

Upland terrace aquifer

“1,200-foot” sand

ST. HELENA PARISHTANGIPAHOA PARISH

BEND INSECTIONBEND INSECTION

A

WEST

A’

EAST

Chicot equivalent aquifer system

Evangeline equivalent aquifer system

Jasper equivalent aquifer system

VERTICAL SCALE GREATLY EXAGGERATED

0

0 10 KILOMETERS

5 10 MILES

5

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

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

Freshwater in sand

Clay

Lithologic contact—Separates clay and sand

 layers. Dashed where approximate. Queried

 where uncertain 

Hydrogeologic contact—Defines boundary

 between conjoined or merged aquifers 

?

Hydrogeologic contact—Defines boundary

 between aquifers or aquifer systems 

EXPLANATION

Figure 3. West-to-east hydrogeologic section through St. Helena 

Parish, Louisiana (modified from Griffith, 2003). Trace of section 

shown on figure 1. 
the northwestern part of the parish to less than 3,000 ft below 

NGVD 29 along the southern parish boundary (fig. 1; Smoot, 

1988). The primary source of recharge to the freshwater aquifers 

in St. Helena Parish comes from infiltration of precipitation 

falling in a large area extending from within the parish to 

about 100 miles northward into the State of Mississippi. 

Flow from streams may also contribute recharge to a lesser 

degree than precipitation. Discharge from aquifers in the 

parish is by leakage into adjacent aquifers, flow into streams, 

and withdrawals from wells. All of the aquifers containing 

freshwater in the parish generally dip south to southwest 

towards the Gulf of Mexico (Griffith, 2003).

 The Chicot Equivalent Aquifer System

The sole aquifer composing the Chicot equivalent aquifer 

system in St. Helena Parish is the Upland terrace aquifer, which 

is a broad, discontinuous, near-surface aquifer that is present 

throughout the parish. The Upland terrace aquifer extends 

westward into East Feliciana Parish, eastward into Tangipahoa 

Parish, and northward into Mississippi. The aquifer crops out 

along ridges and alongside stream valleys within the parish 

and generally dips south to southwest at a rate of 10–30 ft per 

mile. Near the southern parish line, the Upland terrace aquifer 

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

Baton Rouge area. Upland terrace sediments range in grain 

size from clay through silt and sand to gravel and can be over 

300 ft thick. The aquifer is composed primarily of medium- to 

coarse-grained sand (Morgan, 1963). Regionally, the proximity 

of the Upland terrace aquifer to the surface allows the aquifer 

to be recharged by infiltration of rainfall and to transmit some 

of this water to recharge deeper aquifers underlying the parish 

(Griffith, 2003). 

 In 2009, water levels in the Upland terrace aquifer in St. 

Helena Parish ranged from a low of about 75 ft above NGVD 

29 along the southern parish line to a high of more than 250 ft 

above NGVD 29 in the northeastern corner of the parish. The 

general direction of groundwater flow was southward, with 

localized flow direction towards the Amite River and the 

Tickfaw River. In St. Helena Parish, the water-level surface 

generally follows the topography (Tomaszewski, 2011). The 

water-level hydrograph of well SH-56, located in the extreme 

southwestern corner of the parish (fig. 1) and screened in the 

Upland terrace aquifer, indicates that water levels generally 

fluctuate less than 3 ft per year (fig. 4). 

State well-registration records listed 1,201 active water 

wells screened in the Upland terrace aquifer in St. Helena 

Parish in 2015, including 1,074 domestic, 70 public supply, 

49 irrigation, and 8 industrial. Depths of these wells ranged 

from 18 to 366 ft below land surface. Reported yields from 

wells screened in the Upland terrace aquifer in St. Helena Parish 

ranged from 5 to 225 gallons per minute (gal/min) (Louisiana 

Department of Natural Resources, 2015). In 2010, withdrawals 

from the Upland terrace aquifer in St. Helena Parish totaled 

about 0.70 Mgal/d (table 1) and included about 0.07 Mgal/d 

for public supply, 0.53 Mgal/d for rural-domestic use, and 

0.09 Mgal/d for livestock (B.P. Sargent, U.S. Geological Survey, 

written commun., 2015). 

Year

2000 2002 2004 2006 2008 2010 2012 2014

Water level, in feet

55

60

65

70

75

Well: SH-116

Aquifer: "2,800-foot" sand

Aquifer system: Jasper equivalent

Altitude of land surface: 305 ft above NGVD 29

Well depth: 1,634 ft below land surface 

Well: SH-56

Aquifer: Upland terrace

Aquifer system: Chicot equivalent

Altitude of land surface: 77 ft above NGVD 29

Well depth: 160 ft below land surface 

Figure 4. Water levels in well SH-56 screened in the Upland 

terrace aquifer and well SH-116 screened in the Jasper equivalent 

aquifer system in St. Helena Parish, Louisiana (see fig. 1 for well 

locations; U.S. Geological Survey, 2012a). Land surface is measured 

in feet (ft) above the National Geodetic Vertical Datum of 1929 

(NGVD 29).

The Evangeline Equivalent Aquifer System

The aquifers composing the Evangeline equivalent aquifer 

system in St. Helena Parish are the “800-foot,” “1,000-foot,” 

“1,200-foot,” “1,500-foot,” and “1,700-foot” sands of the 

Baton Rouge area (fig. 3). These aquifers contain freshwater 

and are generally fine- to coarse-grained sand. Layers of clay 

usually separate the individual sands; however, many sands 

merge with overlying and underlying sands (Griffith, 2003). 

The altitude of the base of the aquifer system ranges from about 

450 ft below NGVD 29 near the northern parish line to about 

1,200 ft below NGVD 29 near the southern parish line (Griffith, 

2003). In 2003, water levels in the “1,500-foot” and “1,700-

foot” sands ranged from about 215 ft above NGVD 29 in the 

extreme northeastern corner of the parish to about 35 ft below 

NGVD 29 in the extreme southwestern corner of the parish. The 

direction of groundwater flow in the parish was generally to 

the southwest towards withdrawal centers in East Baton Rouge 

Parish (Prakken, 2004). 

State well-registration records listed 26 active water wells 

screened in the Evangeline equivalent aquifer system in St. 

Helena Parish in 2015, including 19 domestic, 3 irrigation, 

3 public supply, and 1 industrial. Depths of these wells ranged 

from 120 to 665 ft below land surface. Reported yields from 

wells screened in the Evangeline equivalent aquifer system 

in St. Helena Parish ranged from about 40 to 300 gal/min 

(Louisiana Department of Natural Resources, 2015). In 2010, 

there were no reported water withdrawals from the Evangeline 

equivalent aquifer system in St. Helena Parish (B.P. Sargent, 

U.S. Geological Survey, written commun., 2015). 

The Jasper Equivalent Aquifer System

The aquifers composing the Jasper equivalent aquifer 

system in St. Helena Parish are the “2,000-foot,” “2,400-foot,” 

and “2,800-foot” sands of the Baton Rouge area (fig. 3). These 
aquifers also generally contain freshwater and are composed of 

fine- to coarse-grained sand. Layers of clay usually separate the 

individual sands; however, many sands merge with overlying 

and underlying sands (Griffith, 2003). 

The altitude of the base of the aquifer system is not well 

defined but is probably about 1,800 ft below NGVD 29 near 

the northern parish line to about 2,000 ft below NGVD 29 near 

the southern parish line (Griffith, 2003). In 2006, the general 

direction of groundwater flow in the “2,800-foot” sand in St. 

Helena Parish was to the southwest, and water levels ranged 

from about 80 ft above NGVD 29 in the northeastern corner 

of the parish to about 20 ft above NGVD 29 in the extreme 

southwestern corner (Fendick, 2007). The hydrograph of well 

SH-116, located in north-central St. Helena Parish (fig. 1) and 

screened in the “2,800-foot” sand, indicates that water levels 

have fluctuated up to 5 ft annually and generally declined from 

2002 to 2011 (fig. 4). 

State well-registration records listed 18 active water wells 

screened in the Jasper equivalent aquifer system in St. Helena 

Parish in 2010, including 14 public supply, 3 industrial, and 

1 domestic. Depths of these wells ranged from 1,422 to 2,120 ft 

below land surface. Reported yields from wells screened in the 

Jasper equivalent aquifer system in St. Helena Parish ranged 

from about 60 to 1,200 gal/min (Louisiana Department of 

Natural Resources, 2015). In 2010, withdrawals from the Jasper 

equivalent aquifer system in St. Helena Parish were about 

0.35 Mgal/d (table 1) and included about 0.32 Mgal/d for public 

supply and 0.03 Mgal/d for industrial use (B.P. Sargent, U.S. 

Geological Survey, written commun., 2015). 

Catahoula Aquifer 

The Catahoula aquifer is present and contains freshwater 

at altitudes from about 2,000 to 2,450 ft below NGVD 29 

in central St. Helena Parish and between about 1,900 and 

about 2,350 ft below NGVD 29 in the northwestern corner 

of the parish. Saltwater is present in the deepest sand layers 

composing the aquifer (Griffith, 2003). State well-registration 

records reported one domestic well registered at a depth of 

2,135 ft yielding 70 gal/min (Louisiana Department of Natural 

Resources, 2015).

Groundwater Quality

A statistical summary of selected water-quality 

characteristics for freshwater samples collected from the Upland 

terrace aquifer (15 wells) and Jasper equivalent aquifer system 

(12 wells) indicates that sample water is generally soft2 and 

does not exceed the U.S. Environmental Protection Agency’s 

Secondary Maximum Contaminant Levels3 (SMCLs) for 

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).

chloride and dissolved solids (table 3). Locally, concentrations 

of iron and manganese may greatly exceed SMCLs in the Jasper 

equivalent aquifer system. Limited samples and stratigraphic 

position indicated that water quality in the Evangeline equivalent 

aquifer system in St. Helena Parish is generally between that 

of the Upland terrace aquifer and the Jasper equivalent aquifer 

system (U.S. Geological Survey, 2012b). 

 Surface-Water Resources 

Surface-water resources in St. Helena Parish are present 

in the regional Lake Maurepas drainage basin. In St. Helena 

Parish, the Lake Maurepas Basin (Hydrologic Unit Code [HUC] 

080702) is divided into three subbasins: the Amite subbasin 

(HUC 08070202) drains the western third of the parish, the 

Tickfaw subbasin (HUC 08070203) drains the central part of the 

parish, and the Tangipahoa subbasin (HUC 08070205) drains 

a small area in the northeastern corner of the parish (fig. 1). 

Streams in St. Helena Parish generally flow in a southerly 

direction, receiving flow from precipitation and groundwater 

within the parish and from areas to the north in Mississippi. In 

2010, about 0.01 Mgal/d of surface water were withdrawn from 

miscellaneous streams (table 1) in St. Helena Parish for livestock 

(table 2). 

Amite Subbasin

The Amite subbasin is drained primarily by the Amite River, 

which flows along most of the western border of St. Helena 

Parish (fig. 1). Multiple smaller streams flow into the Amite 

River, including the East Fork Amite River, Sandy Run, and 

Darling, Buck, Black, and Channey Creeks. The annual average 

flow of the Amite River near Darlington (site number 07377000) 

was about 906 cubic feet per second (ft3/s) during 1951–2014 

from a drainage area of about 580 square miles (mi2) (U.S. 

Geological Survey, 2015). During this same period, the highest 

and lowest annual average flows were 1,924 ft3/s during 1982–83 

and 328 ft3/s during 1999–2000. 

Tickfaw Subbasin

The Tickfaw subbasin is drained primarily by the Tickfaw 

River, which originates in Mississippi, flows into St. Helena 

Parish, and flows out into Livingston Parish to the south of 

Montpelier (fig. 1). Tributaries of the Tickfaw River include 

Twelvemile Creek, Joseph Branch, and East and West Hog 

Branches (fig. 1). The Natalbany River starts in St. Helena 

Parish and flows into Tangipahoa Parish and back into and out 

of St. Helena Parish before flowing into the Tickfaw River in 

Livingston Parish. The Little Natalbany River also begins in St. 

Helena Parish and flows into Livingston Parish. The average flow 

of the Tickfaw River near Liverpool (site number 07375800) 

was about 111 ft3/s during 1956–2014 from a drainage area of 

about 89.7 mi2 (U.S. Geological Survey, 2015). During this same 

period, the highest and lowest annual average flows were 208 

ft3/s during 2012–13 and 52 ft3/s during 2005–6. 
Table 3. Summary of selected water-quality characteristics for freshwater in the Upland terrace aquifer and Jasper equivalent aquifer 

system in St. Helena Parish, Louisiana (U.S. Geological Survey, 2012b).

[Values are in milligrams per liter, except as noted. °C, degrees Celsius; PCU, platinum cobalt unit; μS/cm, microsiemen per centimeter; 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)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

 Upland terrace aquifer, 1940–2001 (15 wells)

Median 20.8 5 32 5.2 6 5.2 30 3 32

10th percentile 20.0 3 24 4.4 4 3.9 <10 <3 25

90th percentile 22.9 16 63 5.6 13 9.6 210 110 46

Number of samples 13 9 13 13 15 15 7 8 12

Percentage of samples 

that do not exceed 

SMCLs

NA 89 NA 0 NA 100 86 88 100

 Jasper equivalent aquifer system, 1954–84 (12 wells)

Median 27.2 16 337 8.6 3 3.9 40 <10 233

10th percentile 23.4 5 171 7.0 1 2.1 20 <10 154

90th percentile 30.0 30 454 9.0 11 4.5 1,000 335 309

Number of samples 12 11 11 12 12 12 8 6 12

Percentage of samples 

that do not exceed 

SMCLs

NA 45 NA 42 NA 100 88 67 92

SMCLs

NA 15 NA 6.5–8.5 NA 250 300 50 500

Tangipahoa Subbasin 

The Tangipahoa subbasin is present only in a small area in 

the northeastern corner of the parish and is drained by Beaver 

Creek. Beaver Creek flows south and east into Tangipahoa Parish, 

eventually flowing into the Tangipahoa River. 

Surface-Water Quality

Water samples taken from the Amite River near Darlington 

during the period 1961–76 and from the Tickfaw River near 

Liverpool during the period 1961–98 were found to be generally 

soft with respect to hardness and did not exceed SMCLs for pH and 

concentrations of chloride, sulfate, or iron (table 4). Limited data 

indicated that dissolved-oxygen concentrations in these rivers were 

generally greater than 5 mg/L, which is considered the minimum 

value for a diverse population of fresh, warmwater biota, including 

sport fish (Louisiana Department of Environmental Quality, 2008). 

Median values for pH in the Amite and Tickfaw Rivers were 6.6 

and 6.3 standard units, respectively. Amite River samples presented 

median values for acid neutralizing capacity of 10 mg/L unfiltered 

as calcium carbonate and for potassium concentrations of 1 mg/L 

filtered. Tickfaw River samples presented median values for acid 

neutralizing capacity of 8.5 mg/L unfiltered as calcium carbonate 

and for potassium concentrations of 0.7 mg/L filtered (U.S. 

Geological Survey, 2012b). 

References Cited 

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 in 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. 

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.

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 Natural Resources, 2015, Strategic Online Natural 

Resources Information System (SONRIS): Louisiana Department of Natural 

Resources database, accessed May 18, 2015, at http://sonris.com/.

Morgan, C.O., 1963, Ground-water resources of East Feliciana and West Feliciana 

Parishes, Louisiana: Louisiana Department of Public Works, 58 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 4. Summary of selected water-quality characteristics for the Amite River and Tickfaw River in St. Helena Parish, Louisiana (U.S. 

Geological Survey, 2012b). 

[Values are in milligrams per liter, except as noted. μS/cm, microsiemen per centimeter; °C, degrees Celsius; SU, standard unit; CaCO3, calcium carbonate; 

μg/L, microgram per liter; —, insufficient data; SMCL, Secondary Maximum Contaminant Level established by the U.S. Environmental Protection Agency 

(2016); NA, not applicable]

Specific

conductance,

field

(μS/cm at 

25 °C)

Oxygen,

dissolved

pH,

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)

Amite River near Darlington, 1961–761

Median 36 9.0 6.6 8 2.0 0.6 3.9 4.2 0.6 180

10th percentile 34 — 6.0 6 1.6 0.2 3.0 3.4 0.1 —

90th percentile 42 — 6.9 10 2.8 0.8 4.8 6.4 2.1 —

Number of samples 16 4 16 16 16 16 16 16 16 2

Percentage of samples 

that do not exceed 

SMCLs

NA NA 75 NA NA NA NA 100 100 100

Tickfaw River near Liverpool, 1961–982

Median 32 8.4 6.3 7 1.6 0.7 3.3 4.0 0.4 60

10th percentile 29 — 5.8 5 1.4 0.5 2.6 3.3 0.2 —

90th percentile 40 — 6.8 9 2.4 0.9 4.2 5.0 2.1 —

Number of samples 12 5 11 12 12 12 11 11 12 5

Percentage of samples 

that do not exceed 

SMCLs

NA NA 45 NA NA NA NA 100 100 100

SMCLs

NA NA 6.5–8.5 NA NA NA NA 250 250 300

1

Site number 07377000.

2

Site number 07375800.

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-drinking-water-standardsguidance-nuisance-chemicals

U.S. Geological Survey, 2012a, Groundwater levels for Louisiana: National 

Water Information System Web Interface, accessed February 18, 2012, at 

http://nwis.waterdata.usgs.gov/la/nwis/gwlevels.

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

Water Information System Web Interface, accessed February 6, 2012, at 

http://nwis.waterdata.usgs.gov/la/nwis/qwdata/.

U.S. Geological Survey, 2015, National Water Information System: Web 

Interface, USGS Water Data for Louisiana, accessed June 1, 2015, at http://

waterdata.usgs.gov/la/nwis/nwis.

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 DOTD, who 

contributed to the content of the fact sheet.

By Vincent E. White and Lawrence B. Prakken

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

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ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

http://dx.doi.org/10.3133/fs20163047