Water Quality in the 

Lower Tennessee River Basin

Tennessee, Alabama, Kentucky, Mississippi, and Georgia, 1999–2001

U.S. Department of the Interior

U.S. Geological Survey

Circular 1233
Points of Contact and Additional Information

The companion Web site for NAWQA summary reports:

http://water.usgs.gov/nawqa/nawqa_sumr.html

Other NAWQA summary reports

River Basin Assessments

Acadian-Pontchartrain Drainages (Circular 1232)

Albemarle-Pamlico Drainage Basin (Circular 1157)

Allegheny and Monongahela River Basins (Circular 1202)

Apalachicola-Chattahoochee-Flint River Basin (Circular 1164)

Central Arizona Basins (Circular 1213)

Central Columbia Plateau (Circular 1144)

Central Nebraska Basins (Circular 1163)

Connecticut, Housatonic, and Thames River Basins (Circular 1155)

Cook Inlet Basin (Circular 1240)

Delaware River Basin (Circular 1227)

Delmarva Peninsula (Circular 1228)

Eastern Iowa Basins (Circular 1210)

Georgia-Florida Coastal Plain (Circular 1151)

Great and Little Miami River Basins (Circular 1229) 

Great Salt Lake Basins (Circular 1236)

Hudson River Basin (Circular 1165)

Island of Oahu (Circular 1239)

Kanawha - New River Basins (Circular 1204)

Lake Erie - Lake Saint Clair Drainages (Circular 1203)

Long Island - New Jersey Coastal Drainages (Circular 1201)

Lower Illinois River Basin (Circular 1209)

Lower Susquehanna River Basin (Circular 1168)

Las Vegas Valley Area and the Carson and Truckee River Basins (Circular 1170)

Mississippi Embayment (Circular 1208)

Mobile River Basin (Circular 1231)

New England Coastal Basins (Circular 1226)

Northern Rockies Intermontane Basins (Circular 1235)

Ozark Plateaus (Circular 1158)

Potomac River Basin (Circular 1166)

Puget Sound Basin (Circular 1216)

Red River of the North Basin (Circular 1169)

Rio Grande Valley (Circular 1162)

Sacramento River Basin (Circular 1215)

San Joaquin-Tulare Basins (Circular 1159)

Santa Ana Basin (Circular 1238)

Santee River Basin and Coastal Drainages (Circular 1206)

South-Central Texas (Circular 1212)

South Platte River Basin (Circular 1167)

Southern Florida (Circular 1207)

Trinity River Basin (Circular 1171)

Upper Colorado River Basin (Circular 1214)

Upper Illinois River Basin (Circular 1230)

Upper Mississippi River Basin (Circular 1211)

Upper Snake River Basin (Circular 1160)

Upper Tennessee River Basin (Circular 1205)

Western Lake Michigan Drainages (Circular 1156)

White River Basin (Circular 1150)

Willamette Basin (Circular 1161)

Yakima River Basin (Circular 1237)

Yellowstone River Basin (Circular 1234)

National Assessments

The Quality of Our Nation‘s Waters—Nutrients and Pesticides (Circular 1225)

Lower Tennessee River Basin 

contact and Web site:

USGS State Representative

U.S. Geological Survey

Water Resources Discipline

640 Grassmere Park, Suite 100

Nashville, TN 37211

e-mail: dc_tn@usgs.gov

http://tn.water.usgs.gov/lten/tenn.html

National NAWQA Program:

Chief, NAWQA Program

U.S. Geological Survey

Water Resources Discipline

12201 Sunrise Valley Drive, M.S. 413

Reston, VA 20192

http://water.usgs.gov/nawqa/

Front cover: Brier Fork Creek near Three Forks, Alabama 

Back cover: Left, spring below Wheeler Dam near Florence, Alabama; middle, Northern studfish–Fundulus 

catenatus; right, electroshock sampling in Fortyeight Creek near Topsy, Tennessee. 
U.S. Department of the Interior

U.S. Geological Survey

Water Quality in the Lower Tennessee River Basin, 

Tennessee, Alabama, Kentucky, Mississippi, and 

Georgia, 1999–2001

By Michael D. Woodside, Anne B. Hoos, James A. Kingsbury, Jeffrey R. Powell, Rodney R. Knight, 

Jerry W. Garrett, Reavis L. Mitchell III, and John A. Robinson

Circular 1233
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

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

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

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Woodside, Michael D., Hoos, Anne B., Kingsbury, James A., Powell, Jeffrey R., Knight, Rodney R., Garrett, Jerry W., 

Mitchell, III, Reavis L., and Robinson, John A., 2004, Water quality in the Lower Tennessee River Basin, Tennessee, 

Alabama, Kentucky, Mississippi, and Georgia, 1999–2001: Reston, Va., U.S. Geological Survey Circular 1233, 38 p.

Library of Congress Cataloging-in-Publication Data

Water quality in the Lower Tennessee River Basin, Tennessee, Alabama, Kentucky, Mississippi, and Georgia,

 1999–2001 / by Michael D. Woodside ... [et. al.].

 p. cm. -- (Circular ; 1233)

 Includes bibliographical references.

 ISBN 0-607-92247-8

 1. Water quality -- Tennessee River Watershed. I. Woodside, M. D. (Michael D.), 

 II. Geological Survey (U.S.) III. U.S. Geological Survey circular ; 1233.

 TD223.5.W385 2003

 363.739’42’0976--dc22 2003063067
iii

Contents

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM ............................................. iv

SUMMARY OF FINDINGS .............................................................................. 1

INTRODUCTION TO THE LOWER TENNESSEE RIVER BASIN ....................................... 3

MAJOR FINDINGS ....................................................................................... 6

Ecology ............................................................................................. 6

REGIONAL PERSPECTIVE—Agricultural Land Use Affects Aquatic Insects ............... 8

Bacteria ............................................................................................. 10

Nutrients ............................................................................................. 12

REGIONAL PERSPECTIVE—Nitrogen in the Tennessee River Contributes to 

 Hypoxia in the Gulf of Mexico ............................................................ 12

REGIONAL PERSPECTIVE—Natural Deposits of Phosphatic Limestone Are a Major 

Source of Phosphorus in Some Streams ............................................. 13

NATIONAL PERSPECTIVE—Nitrate Concentrations in Streams and Ground Water 

 Generally Are Similar to the National Median .......................................... 15

Pesticides .......................................................................................... 16

NATIONAL PERSPECTIVE—Pesticide Detections in the Lower Tennessee River Basin 

Were Higher than National Results ...................................................... 19

Volatile Organic Compounds ..................................................................... 20

Fish Tissue .......................................................................................... 21

STUDY UNIT DESIGN .................................................................................... 22

REFERENCES ............................................................................................. 24

GLOSSARY ................................................................................................ 26

APPENDIX—WATER-QUALITY DATA FROM THE LOWER TENNESSEE RIVER BASIN 

 IN A NATIONAL CONTEXT ..................................................................... 28
iv

National Water-Quality Assessment Program

The quality of the Nation’s water resources is of great interest because it is so integrally linked 

to the long-term availability of water that is clean and safe for drinking and recreation and 

that is suitable for industry, irrigation, and habitat for fish and wildlife. Recognizing the need 

for long-term, nationwide assessments of water resources, the U.S. Congress has appropriated funds since 1991 for the USGS to conduct the National Water-Quality Assessment 

(NAWQA) Program. Scientists in the NAWQA Program work with partners in government, 

research, and public interest groups to assess the spatial extent of water-quality conditions, 

how water quality changes with time, and how human activities and natural factors affect water 

quality. This information is useful for guiding water-management and protection strategies, 

research, and monitoring in different hydrologic and land-use settings across the Nation.

The Lower Tennessee River Basin is one of 51 water-quality assessments initiated since 1991. 

Together, the 51 major river basins and aquifer systems, referred to as “Study Units,” include 

water resources used by more than 60 percent of the population in watersheds that cover about 

half of the land areas of the conterminous United States. Timing of the assessments varies 

because of the Program’s rotational design, in which one-third of all Study Units are intensively 

investigated for 3 to 4 years, with trends assessed every 10 years. As indicated on the map, the 

Lower Tennessee River Basin is part of the third set of intensive investigations, which began in 

1997.

1991–95

1994–98

1997–2001

Not yet scheduled

HighPlains Regional

GroundWaterStudy,

1999–2004

NAWQA Study Units—

Assessment schedule

Lower Tennessee

River Basin
v

What kind of water-quality information does the NAWQA 

Program provide?

Water-quality assessments by a single program cannot possibly address all of the Nation’s 

water-resources needs and issues. Therefore, it is necessary to define the context within which 

NAWQA information is most useful. 

• Total resource assessment—NAWQA assessments are long-term and interdisciplinary, 

and include information on water chemistry, hydrology, land use, stream habitat, and 

aquatic life. Assessments are not limited to a specific geographic area or water-resource 

problem at a specific time. Therefore, the findings describe the general health of the total 

water resource, as well as emerging water issues, thereby helping managers and decision 

makers to set priorities.

• Source-water characterization—Assessments focus on the quality of the available, 

untreated resource and thereby complement (rather than duplicate) Federal, State, and 

local programs that monitor drinking water. Findings are compared to drinking-water 

standards and health advisories as a way to characterize the resource.

• Compounds studied—Assessments focus on chemical compounds that have well-established methods of investigation. It is not financially or technically feasible to assess all 

the contaminants in our Nation’s waters. In general, the NAWQA Program investigates 

those pesticides, nutrients, volatile organic compounds, and metals that have been or are 

currently used commonly in agricultural and urban areas across the Nation. A complete 

list of compounds studied is on the NAWQA Web site at water.usgs.gov/nawqa.

• Detection versus risk—Compounds are measured at very low concentrations, often 10 

to 100 times lower than Federal or State standards and health advisories. Detection of 

compounds, therefore, does not necessarily translate to risks to human health or aquatic 

life. These analyses, however, are useful for identifying and evaluating emerging issues, 

as well as for tracking contaminant levels over time.

• Multiple scales—Assessments are guided by a nationally consistent study design and 

uniform methods of sampling and analysis. Findings thereby pertain not only to water 

quality of a particular stream or aquifer, but also contribute to the larger picture of how 

and why water quality varies regionally and nationally. This consistent, multi-scale 

approach helps to determine if a water-quality issue is isolated or pervasive. It also 

allows direct comparisons of how human activities and natural processes affect water 

quality in the Nation’s diverse environmental settings. 
vi

Introduction to this Report

This report contains the major findings of a 1999–2001 assessment of water quality in the 

Lower Tennessee River Basin. It is one of a series of reports by the National Water-Quality 

Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. 

In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and 

to selected national benchmarks, such as those for drinking-water quality and the protection of 

aquatic organisms. 

This report is intended for individuals working with water-resource issues in Federal, State, or 

local agencies, universities, public interest groups, or in the private sector. The information will 

be useful in addressing a number of current issues, such as the effects of agricultural and urban 

land use on water quality, human health, drinking water, source-water protection, hypoxia and 

excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams 

and ground water in areas where they live, and how that water quality compares to the quality 

of water in other areas across the Nation.

The water-quality conditions in the Lower Tennessee River Basin summarized in this report are 

discussed in detail in other reports that can be accessed from the Lower Tennessee River Basin 

Web site (tn.water.usgs.gov/lten/lten.html). Detailed technical information, data and analyses, 

collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed from 

the national NAWQA Web site (water.usgs.gov/nawqa). 

“The NAWQA Program 

has contributed significantly to Alabama’s 

assessment of water 

resources in the Lower 

Tennessee River Basin.”

Lynn Sisk, 

Alabama Department of 

Environmental Management

“The combined surface- and ground-water 

quality and ecological 

assessments of the Flint 

River Basin by the Lower 

Tennessee River Basin 

NAWQA Program have 

heightened our awareness of how vulnerable 

our water resources are 

due to the karst features 

of the watershed. These 

technical, interdisciplinary 

assessments of watershed 

conditions have helped 

focus our watershed restoration efforts within the 

Flint River Basin.”

Susan Weber,

Flint River 

Conservation Association

Residents of Huntsville, Alabama, have relied on ground water discharging from Big Spring as a 

source of drinking water and for recreation since the early 1800’s. 

From the collection of the Huntsville-Madison County Public Library, Huntsville, Alabama.
Summary of Findings

 Major Influences on Streams and Rivers

• Ground-water contributions to streamflow from springs

• Sediment, bacteria, nutrients, and pesticides in runoff 

from agricultural areas

• Naturally occurring phosphatic limestones

1

Stream and River Highlights

The Lower Tennessee River Basin is one of 

the Nation’s most biologically diverse river systems, with nearly 200 species of fish, 75 freshwater mussels, 50 aquatic snails, and 20 crayfish. 

More than 50 aquatic species are listed as either 

threatened or endangered, and numerous others 

are of special concern or in need of management. 

Caves, springs, sinkholes, and other karst landforms provide unique aquatic habitats that can be 

adversely affected by changes in land use.

Surface water sampled in the Lower Tennessee River Basin generally meets Federal and 

State guidelines for drinking-water quality and 

protection of aquatic life. However, agricultural 

activities have affected water quality, as indicated 

by elevated concentrations of bacteria, nutrients, 

and pesticides in some streams and rivers.

• Sediment from cultivated fields and 

eroded streambanks decreases water clarity and blankets the streambed, degrading 

spawning habitats for many fish, such as 

the saffron darter and laurel dace (p. 7).

• In the Eastern and Western Highland Rim, 

the number of native species was lower for 

streams draining agricultural land compared 

with streams draining forested land (p. 9). 

• During storms, runoff from pasture land 

and other nonpoint sources commonly 

contain fecal-associated pathogens, such as 

Escherichia coli (E. coli). E. coli concentrations in 

the Duck, Elk, and Flint Rivers frequently exceeded 

the United States Environmental Protection Agency 

(USEPA) recreational criterion during and up to 6 days 

following a storm event (p. 10).

• Nonpoint sources—primarily livestock wastes and 

agricultural fertilizers—contribute the largest proportion (about 85 percent) of total nitrogen to streams and 

rivers (p. 12).

• Concentrations of phosphorus in Cane Creek and the 

Duck and Elk Rivers rank in the upper 10 percent of 

473 streams and rivers monitored nationwide by the 

NAWQA Program, yet amounts of phosphorus from 

point and nonpoint sources in these basins are relatively low. Natural deposits of phosphatic limestone 

are a major source of phosphorus in some streams and 

rivers in the Lower Tennessee River Basin (p. 13).

• Fifty-two pesticides, including 38 herbicides, 

11 insecticides, and 3 fungicides, were detected in 

streams and rivers. Aquatic-life guidelines were 

exceeded in less than 6 percent of the samples. 

Pesticides that exceeded aquatic-life guidelines 

include atrazine, cyanazine, and malathion (p. 16).

• Residues of DDT and PCBs frequently were detected 

in whole fish and fish fillets; however, less than 3 

percent of the sites had concentrations that exceeded 

human health action levels or wildlife guidelines 

(p. 21).

 About 1.5 million people reside in the Lower Tennessee River Basin, which 

encompasses about 19,500 square miles, mostly in middle Tennessee and 

northern Alabama, and small areas of Kentucky, Georgia, and Mississippi. 

Surface water is the primary source of drinking water for the cities located 

along the main stem of the Tennessee River and its major tributaries. Large 

springs and ground water are the main sources of drinking water in rural 

areas.

GA

AL

MS

KY

TN

WATER

PASTURE

CULTIVATED

FOREST

URBAN

EXPLANATION

Woods Tims Ford

Nickajack Pickwick Lak

B

e

ear

Creek

88

87

86

o

o

o

36o

35

o

KENTUCKY

Paducah

Reservoir

Normandy

Lake

Lake

Lake

TENNESSEE

GEORGIA

Chattanooga

Columbia

TENNESSEE

ALABAMA

MISSISSIPPI Huntsville

Decatur

Florence

Wilson Lake

Clarks River

Big Sandy River

Kentucky

Lake

Buffalo

River

Beech River

Tennessee River

Shoal

Creek

Elk River Sequatchie River

Guntersville Lake

Paint Rock Rive

F

r

lint Rive

Town Creek

Flint Creek

Wheeler Lake

Duck

River
2 Water Quality in the Lower Tennessee River Basin

 

 Major Influences on Ground Water 

• Karst landforms, such as caves and sinkholes

• Thickness of the regolith (fine-grained soils and 

weathered rock) that overlies the aquifer

• Fecal contamination from animal agriculture and 

failing septic systems

• Pesticides and organic compounds associated with 

urban and agricultural land uses

Ground-Water Highlights

Ground water in the Lower Tennessee River Basin generally meets Federal and State guidelines for drinking-water 

quality. However, elevated concentrations of fecal indicator 

bacteria and the presence of pesticides and volatile organic 

compounds in wells that supply drinking water indicate that 

the Mississippian and Ordovician carbonate aquifers are 

vulnerable to contamination. The karst hydrology of these 

aquifers, with numerous sinkholes and other karst landforms, 

likely increases the probability of ground-water contamination.

• The presence of E. coli in about 29 percent of the 

drinking-water wells and 80 percent of the springs 

sampled indicates that the Mississippian and Ordovician carbonate aquifers are vulnerable to fecal contamination. Concentrations of E. coli ranged from less 

than 1 to 440 colonies per 100 milliliters (col/100 mL) 

in wells that supply drinking water and from less than 

1 to 32,000 col/100 mL in springs (p. 11).

• Although a considerable amount of fertilizer is applied 

to cropland in the Eastern Highland Rim, concentrations of nitrate were less than 2 milligrams per liter 

(mg/L) in about 50 percent of the shallow monitoring 

wells installed near agricultural fields. The relatively 

low concentrations are in part due to fine-grained soils 

that impede the downward movement of water and 

enhance the biochemical transformation of nitrate to 

nitrogen gas (p. 13).

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• Nitrate concentrations were less than the USEPA 

drinking-water standard of 10 mg/L in 71 of the 73 

wells sampled in the Mississippian and Ordovician 

carbonate aquifers (p. 14).

• Thirty-five pesticides, including 28 herbicides, 6 

insecticides, and 1 fungicide, were detected in wells 

and springs sampled in the Mississippian and Ordovician carbonate aquifers. None of the detected pesticides 

exceeded USEPA drinking-water standards (p. 17).

• Volatile organic compounds were detected at low 

concentrations, generally less than 0.2 microgram per 

liter (μg/L), in 67 percent of the wells and springs in 

the Mississippian and Ordovician carbonate aquifers. 

Concentrations of tetrachloroethylene (PCE) and 

trichloroethylene (TCE) exceeded drinking-water 

standards in 2 of 63 wells sampled (p. 20).
10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

EXPLANATION

COASTAL PLAIN TRANSITION

WESTERN HIGHLAND RIM

OUTER NASHVILLE BASIN

INNER NASHVILLE BASIN

EASTERN HIGHLAND RIM

CUMBERLAND PLATEAU

PLATEAU ESCARPMENT AND VALLEYS

VALLEY AND RIDGE

Pickwick Lake

Bear

Creek

88

87

86

o

o

o

36o

35

o

KENTUCKY

Paducah

Normandy

Tims Ford Lake

Lake

Lake

TENNESSEE

GEORGIA

Chattanooga

Columbia

TENNESSEE

ALABAMA

MISSISSIPPI Huntsville

Decatur

Florence

Wilson Lake

Clarks River

Big Sandy River

Kentucky

Lake

Duck

River

Buffalo

River

Beech River

Tennessee River

Shoal

Creek

Elk River Sequatchie River

Guntersville Lake

Paint Rock Rive

F

r

lint River

Town Creek

Flint Creek

Wheeler Lake

3

Figure 1. Water quality in the Lower Tennessee River Basin is affected by the combination of land uses and natural setting.

Introduction to the Lower Tennessee River Basin

Reservoirs along the Tennessee River 

prevent flooding and generate power 

and also are important to the regional 

economy. An estimated 50 million tons 

of goods are transported annually on 

the river in more than 34,000 barges.

Cotton, corn, and soybeans are the 

primary crops grown throughout 

the fertile, rolling terraces and flood 

plains of the Eastern Highland Rim.

The Lower Tennessee River Basin 

Study Unit extends from Walden Gorge 

near Chattanooga, Tennessee, to the confluence of the Ohio River near Paducah, 

Kentucky. The basin encompasses about 

19,500 square miles, mostly in Middle 

Tennessee and northern Alabama, and 

small areas in Kentucky, Georgia, and 

Mississippi (fig. 1). 

Once known for treacherous 

stretches along the main stem, eloquently named by early navigators as the 

Suck and the Boiling Pot, the Tennessee 

River is now highly regulated with few 

free-flowing stream reaches. Reservoirs 

constructed primarily by the Tennessee 

Valley Authority for power generation, 

flood control, and navigation are located 

along the Lower Tennessee River and 

major tributaries. These reservoirs also 

are used extensively for drinking water 

and recreational activities, such as fishing, swimming, and boating.

The Lower Tennessee River Basin 

is divided into nine areas (fig. 1), which 

generally correspond to physiographic 

provinces and to level IV ecoregions 

(Griffith and others, 1997), to provide a 

framework to assess the effects of natural and cultural features on water quality. 

Natural features that can affect water 

quality include geology, soils, climate, 

and surface- and ground-water hydrology. Wastewater discharge, water use, 

and land use are a few of the cultural 

activities that affect water quality.

Urban and Agricultural Land 

Uses Are Prevalent in the 

Eastern Highland Rim and Inner 

and Outer Nashville Basins

Land use in the Lower Tennessee 

River Basin reflects the geology and 

physiography of the area and distribution of the population. Forested land 

covers about 51 percent of the basin. 

Areas with the highest percentages of 

forested land include the Plateau Escarpment and Valleys, Transition, and the 

Western Highland Rim. Pasture land 

covers about 34 percent of the basin 

and is prevalent in the Inner and Outer 

Nashville Basins. Chicken production is 

Pasture land covers much of the Outer and Inner 

Nashville Basins. Karst features, such as sinkholes, 

caves, and disappearing streams, are common and 

increase the vulnerability of surface and ground 

water to contamination.
4 Water Quality in the Lower Tennessee River Basin

concentrated in the Cumberland Plateau, 

whereas cattle production is largest in 

the Inner and Outer Nashville Basins. 

Cultivated land covers about 6 percent 

of the basin and is concentrated primarily in the Eastern Highland Rim. Cotton, 

corn, and soybeans are the primary row 

crops.

About 1.6 million people (U.S. 

Census Bureau, 2003) live in the Lower 

Tennessee River Basin, with about 50 

percent of the population living in the 

Eastern Highland Rim and the Inner 

and Outer Nashville Basins. The largest 

cities (Chattanooga, Tennessee; Huntsville, Alabama; and Decatur, Alabama) 

are along the main stem of the Tennessee River. 

Diverse Assemblages of Fish, 

Mussels, and Snails Live in the 

Basin

The Lower Tennessee River Basin 

is recognized nationally for its diverse 

aquatic fauna and is home to nearly 200 

species of fish, 75 freshwater mussels, 

50 aquatic snails, 20 crayfish, and the 

continent’s largest salamander, the 

hellbender (Cryptobranchus alleganiensis). The U.S. Fish and Wildlife Service 

has listed 51 aquatic species (fish and 

mussels) in the Lower Tennessee River 

Basin as either threatened or endangered 

and numerous others as special concern 

or in need of management (Tennessee 

Valley Authority, 2003).

Most of the aquatic diversity is concentrated in the free-flowing streams—

most notably, the Duck River. The Duck 

River spans over 260 miles across a 

variety of landscapes from the cedar 

glades of the Eastern Highland Rim, 

through karst topography of the Central 

Basin, to the dissected forested hills of 

the Western Highland Rim. 

Currently home to 146 species of 

fish, 52 species of mussels, and more 

than 25 species of snails, the Duck River 

is considered one of the most diverse 

rivers in North America, containing 

more species of fish than all of Europe. 

The Nature Conservancy recognized the 

upper Duck River as a hot spot for 

freshwater species at risk, with 33 

imperiled and vulnerable fish and mussel 

species (Masters and others, 1998).

Water Availability Is an Issue 

in Some Areas of the Basin 

Although surface water is the 

primary source of drinking water for 

most of the cities along the major tributaries and the main stem of the Lower 

Tennessee River, ground water is relied 

on as a source of drinking water in rural 

areas and some cities (fig. 2). Large 

springs prevalent in the Eastern and 

Western Highland Rim and the Inner and 

Outer Nashville Basin also are a source 

of drinking water in rural areas.

Although the Lower Tennessee 

River Basin generally is noted for its 

abundant water resources, water availability is an issue in some areas of the 

basin. Balancing increased demands 

for water for waste assimilation and for 

agricultural, commercial, industrial, 

and public-supply uses with the need 

to maintain instream flows for aquatic 

fauna has become a major issue within 

the Duck River Basin, upstream from 

Columbia, Tennessee.

Redline darter

Pheasantshell

Industrial

Public supply

Livestock

Irrigation

Domestic

Commercial

0

100

50

150

200

250

300

350

FRESHWATER WITHDRAWALS, IN MILLION GALLONS PER DAY

Surface water

Ground water

WITHDRAWAL TYPE

400

Figure 2. In 1996, surface water accounted 

for about 73 percent of withdrawals for 

public supply in the Lower Tennessee River 

Basin.

Anglers enjoy catching small- and large-mouth bass, rock bass, and many other sport 

fish in the streams, rivers, and reservoirs throughout the Lower Tennessee River Basin. 

In addition to sport fishing, the basin also is recognized nationally for its diverse aquatic 

fauna.
Introduction to the Lower Tennessee River 5

1999 2000 2001

STREA

MFLO

W, NI CUB CI

FEET PER SECOND

10

100

1,000

10,000

100,000

WATER YEARS

75th percentile

Average streamflow 1934–94

25th percentile

Streamflow 1999–2001

Flint River

at Brownsboro, Alabama

Surface- and Ground-Water 

Resources Are Vulnerable to 

Contamination in Karst Areas

Throughout most of the Inner and 

Outer Nashville Basins and the Eastern 

and Western Highland Rims (fig. 1), 

ground water moves through regolith, 

a mixture of soil and weathered rock, 

from 10 to more than 100 feet thick, and 

subsequently into underlying carbonate 

aquifers. These carbonate aquifers are 

important sources of drinking water; 

however, karst landforms, such as caves, 

sinkholes, and springs, increase the 

susceptibility of ground water to contamination. In karst areas, contaminants 

on the land surface can be transported 

rapidly into nearby streams and ground 

water.

Annual Streamflows Were 

Above and Below Average 

Conditions during the Sampling 

Period

Water quality in streams, rivers, 

and shallow ground water often varies in 

response to hydrologic conditions; thus, 

information on streamflows is critical 

for assessing water-quality conditions. 

Because annual streamflows were above 

and below average conditions during 

the 3-year sampling period in the Lower 

Tennessee River Basin, water-quality 

data collected during the study reflect a 

range of hydrologic conditions (fig. 3).

In water year 1999 (October 

1, 1998, to September 30, 1999), 

streamflows at most sites were similar 

to average streamflows (fig. 3). Despite 

a few large storms in April 2000, water 

year 2000 was dry, and streamflows at 

many sites were about 40 percent less 

than average streamflows. Numerous 

storms throughout water year 2001 

resulted in above-average streamflows.

Surface-Water-Quality Assessment 

Focused on the Effects of Land Use 

Surface-water-quality assessments 

focused on describing water-quality 

conditions in four streams draining 

predominately pasture and cultivated 

land and in two rivers draining a mixture 

of land uses and natural settings. 

Biological assessments also were conducted at streams in the Eastern Highland Rim and Western Highland Rim 

to assess the effects of agricultural land 

use on aquatic communities. See pages 

22–23 for additional information on 

study design and sampling locations.

Ground-Water-Quality 

Assessment Focused on 

Carbonate Aquifers

Ground-water-quality assessments 

focused on carbonate aquifers underlying the Eastern Highland Rim and the 

Inner and Outer Nashville Basins. Karst 

landforms and agricultural activities in 

these areas increase the susceptibility of 

ground water to contamination. 

Carbonate aquifers in the Eastern 

Highland Rim and the Inner and Outer 

Nashville Basins are important sources 

of drinking water for public supply 

systems and for domestic uses in rural 

settings. Estimated ground-water withdrawals from the Mississippian aquifer, 

underlying the Eastern Highland Rim, 

were about 40 million gallons per day 

(Mgal/d) in 1995. Within the Eastern 

Highland Rim, the City of Huntsville, 

Alabama, is the largest ground-water 

user, withdrawing about 14 Mgal/d 

from shallow (less than 125 feet) wells. 

The Ordovician aquifer, underlying the 

Inner and Outer Nashville Basins, is 

used primarily for domestic supply in 

rural areas, with estimated ground-water 

withdrawals of about 2.4 Mgal/d in 1995 

(Kingsbury and others, 1999). See pages 

22–23 for additional information on 

study design and sampling locations.

Figure 3. The 3-year sampling period included both wet and dry years; thus, waterquality data collected during the study reflect a range of hydrologic conditions.

Additional Information

For a detailed description of the 

natural and human factors affecting water quality in the lower 

Tennessee River Basin, refer to 

Kingsbury and others (1999).

The report is available at 

http://water.usgs.gov/pubs/wri/

wri994080
6 Water Quality in the Lower Tennessee River Basin

Major Findings

Karst Landforms Provide 

a Unique Habitat for 

Diverse Populations of 

Fish, Mussels, and Snails

The Lower Tennessee River Basin 

is recognized nationally for its diverse 

aquatic fauna. In spite of recent losses 

(extinction) of fishes, such as the harelip 

sucker (Lagochila lacera) and whiteline 

topminnow (Fundulus albolineatus), and 

mussels, such as the sugarspoon (Epioblasma arcaeformis) and acornshell 

(Epioblasma haysiana), the Lower Tennessee River still ranks as one of North 

America’s most biologically diverse 

river systems. The Lower Tennessee 

River Basin contains about 200 fish, 75 

freshwater mussels, 50 snails, and 20 

crayfish species with the highest diversity (or number) of species concentrated 

in karst areas. Caves, springs, sinkholes, 

and other karst landforms provide 

unique habitats that deliver a sustained, 

clean source of water to streams and 

rivers. Unfortunately, water resources 

associated with these landforms are 

vulnerable to changes in land use.

Fish Distributions Vary Across 

the Eastern Highland Rim 

Because of Variations in Base 

Flow

Although the Eastern Highland 

Rim is considered a relatively homogeneous area in terms of its karst geology 

and physiography, hydrological and 

ecological variation exists. One of the 

most important factors influencing fish 

distributions in the Eastern Highland 

Rim is base flow (Powell, 2003). Base 

flow largely consists of ground-water 

contributions, which are highly variable in karst settings. For example, base 

flows in the Barrens (fig. 4) are highly 

influenced by sinkholes and springs, 

which are scattered across the landscape and serve as collection points for 

surface runoff and conduits for runoff to 

streams. Relatively shallow, low-gradient streams of the Barrens tend to have 

lower base flows than streams in the 

Dissected Tablelands, but not as low as 

those in the Moulton Valley. Common 

fishes include the flame chub (Hemitremia flammea), blacknose dace (RhinichEcology

Whether spawning in a clear spring run or attaching eggs to vegetation found only 

in headwater wetlands, many fish species in the Lower Tennessee River Basin are 

dependent on springs, caves, and ground-water seepage for survival. Freshwater 

mussels depend on springs and other karst landforms to provide a clean, sustained 

source of water.

Cumberland Monkeyface

Quadrula intermedia Smooth Rabbitsfoot

Quadrula cylindrica

Slackwater Darter,

Etheostoma boschungi

Birdwing Pearlymussel

Lemiox rimosus

Barrens Topminnow

Fundulus julisia

Flame Chub

Hemitremia flammea

Photograph by J.R. Shute,Conservation Fisheries, Inc.

Photograph by J.R. Shute,Conservation Fisheries, Inc.

Figure 4. Three distinct areas were identified in the Eastern Highland 

Rim ecoregion based on differences in streamflow and fish distributions.

Barrens

Dissected Tablelands

Moulton Valley

Lower Tennessee

River Basin

TN

AL

KY

MS GA
 7

thys atratulus), and banded sculpin 

(Cottus carolinae), all of which prefer 

cool, spring-fed conditions.

The Moulton Valley is composed of 

deep, low-gradient streams that slowly 

meander across the landscape. Although 

ground water is an important component 

of streamflow, many of the headwater 

reaches of Moulton Valley streams 

tend to go dry periodically because 

of the sandstone-capped hills. These 

sandstones have low porosity, which 

decreases ground-water storage and base 

flow. Base flows in the Moulton Valley 

are lower than in either of the other two 

areas. Fish commonly found in these 

streams include the western mosquitofish (Gambusia affinis), spotfin shiner 

(Cyprinella spiloptera), and several 

sunfish species (Lepomis sp.). These 

fish are capable of quickly retreating to 

larger streams or rivers during periods 

of low base flow or surviving in isolated 

pools that remain in partially dry stream 

channels.

The most biologically and topographically diverse area in the Eastern 

Highland Rim is the Dissected Tablelands. Because of numerous springs in 

the Dissected Tablelands, base flows are 

considerably higher than in comparably 

sized streams in the Barrens or Moulton 

Valley. It is not uncommon for streams 

in the Dissected Tablelands to support 

30 to 40 native species of fish, such as 

the largescale stoneroller (Campostoma 

oligolepis), scarletfin shiner (Lythrurus 

fasciolaris), longear sunfish (Lepomis 

megalotis), and black darter (Etheostoma duryi).

Fish Communities Are Affected 

by Sediment Deposition

State agencies in the Lower Tennessee River Basin list sediment in agricultural runoff as the most significant of all 

river pollutants (Tennessee Department 

of Environment and Conservation, 2002; 

Alabama Department of Environmental 

Management, 2002). Agriculture also 

is listed as the leading source of stream 

impairment nationally (U.S. Environmental Protection Agency, 2002b). 

As the percentages of cropland 

increase in watersheds in the Dissected 

Tablelands, the percentage of the streambed covered with sediment increases, 

causing a decline in the percentage of 

insect-eating and crevice-spawning 

fishes (fig. 5). Increased sediment 

decreases water clarity and eliminates 

suitable spawning habitat for insecteating and crevice-spawning fishes. 

Insect-eating fish require clear water to 

locate their prey. As sediment blankets 

the stream bottom, it destroys the habitat 

needed by aquatic insects to construct 

nests and forage. 

Crevice spawners, such as the 

laurel dace, are fishes that deposit or 

physically attach eggs to rocks or in the 

cracks and crevices between them. As 

these areas fill with sediment, the egg 

survival rate is reduced. 

Ecology 7

Sediment from cultivated fields, construction sites, and eroded streambanks 

adversely affects fish spawning and 

feeding by filling in crevices between and 

under rocks. 

Figure 5. Fishes such as the laurel dace (Phoxinus saylori), which feeds 

on insects, and the saffron darter (Etheostoma flavum), which requires 

clean substrate to spawn (crevice spawners), were negatively affected 

by increases in sedimentation associated with agricultural land use in the 

Dissected Tablelands.

Drawing by Bob Savannah, U. S. Fish and Wildlife Service

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8 Water Quality in the Lower Tennessee River Basin

AGRICULTURAL LAND USE AFFECTS AQUATIC INSECTS

Sensitive organisms Pollution-sensitive insects

Pollution-tolerant insects

0 5 10 15 20 25 30

PERCENTAGE OF BASIN IN CROPLAND

3

4

5

6

POLLUTION-TOLERANT INSECTS

(A

VERA

GE WEIGHTED V

ALUE)

0

10

20

30

NUMBER OF POLLUTION-SENSITIVE INSECTS

Less than 5 5-10 11-30

0.1

0.4

0.7

1.0

1.3

2.0

3.0

4.0

Nitrate

Chloride

MEDIAN NITRATE CONCENTRATION,

IN MILLIGRA

MS PER LITER

MEDIAN CHLORIDE

CONCENTRATION,

IN MILLIGRA

MS PER LITER

PERCENTAGE OF BASIN IN CROPLAND

7 40

5.0 1.6

Mayflies (Ephemeroptera), stoneflies (Plecoptera), 

and caddisflies (Trichoptera) are collectively referred 

to as EPT taxa. Most of these organisms are considered to be pollution-sensitive insects.

Photograph by Dean Hansen

Photograph by Eric D. FleekNorth Carolina Division ofWater Quality

Photograph by Dean Hansen

Photograph byDean Hansen

Pollution-tolerant insects

Pollution-sensitive insects

Photograph by Eric D. Fleek, North CarolinaDivision of Water Quality

Pollution-tolerant and pollution-sensitive are examples 

of biological measures or metrics that group aquatic insects 

according to their feeding habits, means of locomotion, tolerance levels, or habitat preferences. Metrics are used in environmental assessments to express how biological communities respond to changing environmental conditions, such as 

nutrient levels or water temperature. For example, pollutionsensitive insects, such as caddisflies, decline in abundance 

when their food-trapping nets become choked with algae and 

silt that result from excessive nutrients or sediment. 

In streams draining the Eastern Highland Rim and 

Western Highland Rim, nitrate and chloride concentrations 

increase with increasing amounts of cropland and correlate 

with a decrease in the number of pollution-sensitive insects 

and an increase in pollution-tolerant insects. The number of 

pollution-sensitive insects decreased from 28 to 6, and the 

average weighted value for pollution-tolerant insects, based 

on criteria developed for southeastern streams (Cuffney, 

2003), increased from 4.1 to 6.1, when the percentage of 

cropland increased from 0.8 percent to 30 percent. 

Although nitrogen and chloride occur naturally in 

the environment and are essential to all plant growth, the 

application of agricultural fertilizers to cropland increases 

the concentrations of these constituents in streams and rivers 

above natural, or background, levels. On average, 85 percent 

of the total nitrogen transported by streams and rivers in 

the Lower Tennessee River Basin originates from nonpoint 

sources, such as agricultural fertilizers and livestock waste 

(see page 12 for additional information on nutrients).

Black flies (Simulid sp.) and midges (chironomids) 

are considered some of the most tolerant of 

aquatic insects. They tend to thrive by out-competing other insects that are less tolerant of pollution.

Drawing by Uta Gruenert

Drawing by Uta Gruenert

Caddisfly
Stream Health Is Affected by 

Land Use

Fish and aquatic insects are used 

as indicators of stream health because 

they integrate water-quality and habitat 

conditions over time. Unlike waterquality analyses, which provide only a 

snapshot in time of stream conditions, 

fish and aquatic insect community data 

provide a long-term, living indication of 

stream health. Biotic health scores were 

used to compare the health of fish and 

aquatic insect communities among the 

streams in the Eastern Highland Rim 

and the Western Highland Rim. These 

scores combine a number of community 

metrics, such as the abundance of pollution-tolerant and pollution-sensitive 

insects and the abundance of crevicespawning and insect-eating fishes, into 

individual stream health scores (fig. 6). 

Fish scores were based on 12 metrics 

designed to assess three broad community segments—the number of native 

species, the types of feeding groups 

represented, and the physical condition 

of the fish. Aquatic insect scores were 

based on six metrics designed to assess 

these same broad segments of the community.

Fish health scores, particularly 

those associated with numbers of 

native species and feeding group 

composition, were lower for 

Ecology 9

Figure 6. Fish and aquatic insect health scores varied in relation to land use. Health 

scores were highest in the forested basins of the Western Highland Rim and lowest in the 

agricultural basins of the Eastern Highland Rim. 

INSECT SCORE

(top)

FISH SCORE

(bottom)

Good

Fair

Poor

STREAM HEALTH

Western Highland SCORE

Rim

Eastern Highland

Rim

EXPLANATION

Streams draining the Western Highland

Rim have higher base flows and typically

5 to 10 times more fish species than

similar sized streams in the Eastern

Highland Rim. The higher base flows

are because of natural factors, such as

geology, but the increase in fish diversity

is likely a result of good water quality

and the absence of sediment.

streams draining agricultural land 

than for streams draining forested 

land. Streams draining forested 

basins in the Western Highland 

Rim typically had 5 to 10 times 

more fish species than streams 

draining agricultural basins in 

the Eastern Highland Rim. The 

insect-eater abundance and numbers of native species were lower 

in the predominantly agricultural 

basins and higher in the forested 

basins. 

Aquatic insect health scores also 

were lower for streams draining 

agricultural land than for streams 

draining forested land. Numbers 

of pollution- sensitive insects 

Additional Information

For more information on the natural setting and fishes of the Eastern 

Highland Rim, refer to Powell 

(2003). 

The report is available at 

http://water.usgs.gov/pubs/wri/

wri024268
10 Water Quality in the Lower Tennessee River Basin

Fecal Contamination of 

Surface- and GroundWater Resources

Water-quality assessments conducted by State agencies indicate that 

102 streams throughout the Lower Tennessee River Basin are impaired for recreational uses because of elevated levels 

of pathogens. Although Escherichia 

coli (E. coli) bacteria are not typically 

pathogenic (disease-causing), the presence of E. coli indicates fecal contamination from warm-blooded animals and 

has been associated with waterborne 

pathogens.

Swimming, canoeing, and other 

water-contact activities in fecal-contaminated streams and rivers can result 

in infections of the eyes, ears, nose, and 

throat. In addition, ingestion of fecalcontaminated water can cause mild to 

acute gastroenteritis, with symptoms that 

include vomiting, diarrhea, stomachache, nausea, and fever. These symptoms often appear several days following 

water-contact activities; thus, people 

rarely associate these symptoms with 

exposure to fecal-contaminated water. 

Fecal-contaminated water may pose an 

even greater risk to infants, young children, and people with severely compromised immune systems.

Recreational Criterion is 

Infrequently Exceeded During 

Base Flows

E. coli concentrations in streams 

and rivers during base flows generally 

were less than the USEPA recreational 

criterion of 298 col/100 mL (U.S. Environmental Protection Agency, 1986a), 

except at Hester Creek (fig. 7). About 

53 percent of the base-flow samples 

from Hester Creek exceeded the USEPA 

recreational criterion. The most likely 

sources of fecal contamination in Hester 

Creek during base flows are failing 

septic systems and livestock that have 

direct access to the stream.

Recreational Criterion Is 

Frequently Exceeded During 

Stormflows

Numerous people enjoy watercontact activities, such as canoeing and 

kayaking, along the Elk, Duck, and 

Flint Rivers. Participating in watercontact activities in these rivers during 

and following a storm may increase the 

risk of developing infections caused by 

waterborne pathogens.

During stormflows, runoff 

from pasture and forested lands and 

other nonpoint sources that contain 

fecal- associated pathogens washes into 

streams and rivers. E. coli concentrations in the Duck, Elk, and Flint Rivers 

during and up to 6 days following a 

storm event ranged from 46 to 100,000 

col/100 mL and frequently exceeded the 

USEPA recreational criterion (fig. 7).

Turbidity Is an Indicator of 

Fecal Contamination in Rivers

During stormflows, sediment 

often is washed into streams and rivers, 

increasing the turbidity of the water. 

Increased turbidity in the Duck, Elk, and 

Flint Rivers is correlated with increased 

concentrations of E. coli. Turbidity 

measurements above 20 nephelometric 

units generally correspond to E. coli

concentrations that exceed the USEPA 

recreational criterion (fig. 8).

Bacteria

E. COLI CONCENTRATIONS, IN COLONIES PER 100 MILLILITERS

ELK RIVER

FLINT RIVER

DUCK RIVER

SCARHAM CREEK

NORTH FORK

HESTER CREEK

CANE CREEK

0.1 1 10 100 1,000 10,000 100,000 1,000,000

0.1 1 10 100 1,000 10,000 100,000 1,000,000

STREAMS

RIVERS

USEPA recreational criterion

BASE FLOW

(during and up to 6 days

following a storm)

CREEK

STORMFLOW

Figure 7. Concentrations of E. coli bacteria detected in streams and rivers in the Lower 

Tennessee River Basin exceeded recreational criterion rarely during base flows but 

frequently during stormflows.

During stormflows, E. coli bacteria in rivers 

and streams frequently exceed the USEPA 

recreational criterion, increasing the risks of 

developing waterborne infections.
Bacteria 11

Understanding the relation between 

the turbidity of the Duck, Elk, and 

Flint Rivers and E. coli concentrations enables canoers, kayakers, and 

other water-sport enthusiasts to make 

informed decisions about exposure to 

fecal-contaminated waters during and 

following storms.

Carbonate Aquifers Are Vulnerable to Fecal Contamination

Sinkholes, caves, and other karst 

landscape features increase the vulnerability of the Mississippian and Ordovician carbonate aquifers to fecal contamination. During heavy rainfalls, surface 

runoff containing pathogens can be 

transported quickly into carbonate 

aquifers. Curriero and others (2001) 

reported a strong association between 

waterborne disease outbreaks in the 

Nation during 1948–94 and extreme 

rainfall events.

The detection of E. coli in drinking water is a human health concern. E. 

coli bacteria were detected in at least 

29 percent of the wells sampled in the 

Mississippian and Ordovician carbonate 

aquifers, in concentrations ranging from 

less than 1 to 440 col/100 mL (fig. 9). 

E. coli Frequently Are Detected 

at Elevated Levels in Springs

Springs are often considered 

sources of safe drinking water. The frequency of detection and variability of E. 

coli concentrations in springs from the 

Mississippian and Ordovician carbonate 

aquifers, however, indicates a potential 

human health concern.

E. coli bacteria were detected in 8 

of the 10 springs sampled in the Ordovician carbonate aquifer, with concentrations ranging from less than 1 to 32,000 

col/100 mL (fig. 9). Johnson (2002) 

reported similar findings in springs from 

carbonate aquifers in the Upper Tennessee River Basin. 

The quality of water from springs 

can be extremely variable over time, 

depending on land-use activities and 

rainfall conditions. Two springs in 

the Mississippian carbonate aquifer 

were sampled at least bimonthly for 2 

years and had E. coli concentrations 

that ranged from less than 1 to 1,600 

col/100 mL.

USEPA

recreational criterion

1 10 100 1,000

TURBIDITY, IN NEPHELOMETRIC TURBIDITY UNITS (NTU)

10

100

1,000

10,000

100,000

E. C

OLI CONCENTRATION, IN COLONIES PER 100 MILLILITERS

Turbidity equals 4 NTU

Turbidity equals 260 NTU

Figure 8. The correlation between E. coli and turbidity can be 

used by canoers and kayakers to estimate the level of fecal 

contamination in the Flint River before entering the water. 

E. COLI CONCENTRATION, IN COLONIES PER 100 MILLILITERS

1

10

100

1,000

10,000

100,000

MISSISSIPPIAN

CARBONATE

AQUIFER

WELLS

ORDOVICIAN

CARBONATE

AQUIFER

WELLS

SPRINGS

Figure 9. The presence of E. coli bacteria 

in about 29 percent of the wells and 80 percent of the springs indicates that Mississippian and Ordovician carbonate aquifers 

are vulnerable to fecal contamination. 

Additional Information

For additional information on 

fecal-indicator bacteria in the Flint 

River Basin, refer to Hoos and 

others (2002). 

The report is available at

http://water.usgs.gov/pubs/wri/

wri014185
12 Water Quality in the Lower Tennessee River Basin

Why are Nutrients a 

Concern in Streams and 

Ground Water?

Nitrogen and phosphorus are 

naturally occurring nutrients that are 

present in streams and ground water, but 

human activities add significant quantities through nonpoint and point sources. 

Nonpoint sources include agricultural 

fertilizer, livestock manure, failing septic 

systems, and atmospheric deposition 

of fossil-fuel combustion by-products. Point sources include municipal 

and industrial wastewater. Excessive 

amounts of nutrients in streams and 

lakes can accelerate growth of aquatic 

plants and may degrade the aquatic 

ecosystem and restrict recreational use. 

According to water-quality assessments 

conducted by State agencies in 2002, 93 

streams in the Lower Tennessee River 

Basin are impaired because of nutrient enrichment. In rural areas where 

untreated water from wells is the primary source of drinking water, nitrate in 

ground water is a concern because 

elevated concentrations are hazardous to human health.

Nonpoint Sources Are 

Major Contributors of 

Nitrogen to Streams and 

Rivers

Nonpoint sources—primarily livestock waste and agricultural 

fertilizers—contribute the largest 

proportion (about 85 percent) of 

total nitrogen to streams and rivers 

in the Lower Tennessee River Basin 

compared to about 10 percent from 

natural sources (Alexander and others, 2000) and about 5 percent from 

point sources. Statistical analyses 

indicated a strong relation between 

amounts of agricultural fertilizer 

applied and livestock waste in a 

watershed and the amount of total 

nitrogen that is transported annually in streams and rivers (fig. 10). 

Relatively small amounts of total 

nitrogen were transported (less than 

2 tons per square mile per year [(tons/

mi2)/yr] in the Buffalo River, which 

drains mostly forested land. The largest amounts of total nitrogen [greater 

than 4 (tons/mi2)/yr] were transported 

in Town Creek, which drains predominantly pasture land that contains a large 

number of confined-animal operations.

Nutrients

Point and nonpoint sources of nitrogen in the Lower 

Tennessee River Basin not only cause impairment of 

streams and rivers within the basin but also pose an environmental threat to the Gulf of Mexico downstream, which 

is experiencing widespread hypoxia and degradation of 

aquatic resources (Rabalais, 1996). Annual nitrogen loads 

from the Tennessee River Basin comprise less than 5 

percent of the annual nitrogen load of the entire Mississippi River Basin; however, about 90 percent of the nitrogen 

transported in the lower Tennessee River is delivered to the 

Gulf of Mexico. Nitrogen is readily assimilated by natural 

processes in small streams but is slowly assimilated in large 

rivers, such as the Tennessee River. Because agricultural and 

wastewater sources of nitrogen are concentrated along the 

main stem of the lower Tennessee River, nitrogen from these 

sources is readily transported from the Tennessee River 

Basin to the Gulf of Mexico. In fact, the watersheds in the Lower Tennessee River Basin deliver more than 1.5 (tons/mi2

)/yr of nitrogen to the 

Gulf of Mexico, compared to less than 0.9 (ton/mi2)/yr contributed by 

most watersheds in the Mississippi River Basin (Alexander and others, 

2000).

0

2

4

6

T

0 10 20 30 OTAL NITROGEN TRANSPORTED ANNUALLY

IN STREAMS AND RIVERS, IN TONS PER

SQUARE MILE PER YEAR

TOTAL NITROGEN FROM COMMERCIAL

FERTILIZER AND LIVESTOCK WASTE, IN TONS PER

SQUARE MILE PER YEAR

Figure 10. The amount of agricultural fertilizer 

applied and livestock waste produced in a basin 

relates strongly to the amount of total nitrogen 

transported annually in streams and rivers in the 

basin (statistical correlation coefficient of 0.65).

NITROGEN IN THE TENNESSEE RIVER CONTRIBUTES TO HYPOXIA 

IN THE GULF OF MEXICO

EXPLANATION

Nitrogen delivered to the

Gulf of Mexico, in percent

0 to 20

20 to 30

30 to 50

50 to 80

80 to 90

Greater than 90

Lower Tennessee

River Basin

From Alexander and others, 2000
Point Sources of Nitrogen Can 

Affect Streams and Rivers 

When Streamflows Are Low

Point sources, such as municipal 

and industrial discharges, generally 

contribute a small percentage (about 5 

percent) of the total nitrogen transported 

annually in streams and rivers in the 

Lower Tennessee River Basin. Point 

sources, however, can account for a significant percentage of the total nitrogen 

in streams and rivers during base-flow 

conditions in the summer and early fall 

when inputs from nonpoint sources are 

reduced. For example, point sources 

account for 50 to 90 percent of the total 

nitrogen in the Duck River during baseflow conditions in the summer (Hoos 

and others, 2000). During periods of low 

streamflow, which generally coincide 

with optimal conditions for algal growth 

(long periods of sunlight and warm 

temperatures), point sources of nitrogen 

can impair stream health by promoting 

the growth of nuisance algae. 

Nitrate Concentrations in 

Shallow Ground Water Are 

Lower than Expected

Although a considerable 

amount of fertilizer (about 45 

(tons/mi2)/yr) is applied to cropland in the Eastern Highland Rim, 

nitrate concentrations are generally 

low in shallow agricultural monitoring wells (generally less than 

60 feet deep). About 50 percent 

of the agricultural monitoring 

wells had concentrations less than 

2 mg/L (fig. 11)—a commonly 

used threshold indicating input of 

anthropogenic nitrogen to ground 

water (Mueller and others, 1995). 

Agricultural monitoring wells with 

elevated nitrate concentrations also 

had elevated total pesticide concentrations. 

Denitrification and the uptake 

of nitrogen by plants are two 

natural processes that moderate 

nitrate concentrations in ground 

water. In the Mississippian carbonNutrients 13

NATURAL DEPOSITS OF PHOSPHATIC LIMESTONE ARE A MAJOR 

SOURCE OF PHOSPHORUS IN SOME STREAMS 

Figure 11. Nitrate concentrations in shallow 

agricultural monitoring wells are strongly correlated to dissolved-oxygen levels, indicating that 

denitrification may reduce the amount of nitrate 

transported into the Mississippian carbonate 

aquifer.

ate aquifer, low concentrations of nitrate 

(less than 2 mg/L) are associated with 

low concentrations of dissolved oxygen, 

suggesting the removal of nitrate by 

denitrification (the biochemical conversion of nitrate to nitrogen gas). The 

predominantly fine-grained soils and 

weathered rock that overlie bedrock 

PHOSPHATIC LIMESTONE

OUTCROPS

0 2 4 6 8 0

0.6

1.2

TOTAL PHOSPHORUS CONCENTRATION,

IN MILLIGRAMS PER LITER

TOTAL PHOSPHORUS FROM COMMERCIAL

FERTILIZER AND LIVESTOCK WASTE, IN TONS

PER SQUARE MILE PER YEAR

National median

Duck River

Cane Creek

Elk River

Recommended guideline

Adapted from

Smith and Whitlatch, 1940

Understanding naturally occurring sources and levels of phosphorus in 

streams and rivers is critical in setting attainable numeric criteria for protection of 

stream ecology and in managing the sources of phosphorus contributed by human 

activities. Instream concentrations of phosphorus in basins containing outcrops 

of phosphatic limestone, such as Cane Creek and the Duck and Elk Rivers, are 

naturally elevated and exceed the USEPA-recommended guideline (U.S. Environmental Protection Agency, 1986b) of 0.1 mg/L by almost eightfold. Among 473 

streams and rivers monitored nationwide in the NAWQA Program, Cane Creek 

and the Duck and Elk Rivers rank in the upper 10 percent for phosphorus concentrations, even though amounts of phosphorus from point and nonpoint sources in 

these basins are relatively low (Hoos and others, 2000).

DISSOLVED OXYGEN, IN MILLIGRAMS PER LITER

NITRATE CONCETRATION,IN MILLIGRAMS PER LITER

Median value

6 0

2

4

6

8

10

0 2 4 8 10

Threshold indicating

input from human

activities
14 Water Quality in the Lower Tennessee River Basin

in the Mississippian carbonate aquifer 

facilitate denitrification by slowing the 

downward movement of recharge water, 

leading to decreases in dissolved oxygen 

and nitrate concentrations. Nitrate 

concentrations were elevated (greater 

than 2 mg/L) where dissolved-oxygen 

concentrations were high (fig. 11). 

These samples likely represent parts of 

the aquifer where dissolved oxygen is 

replenished by ground-water recharge 

and denitrification does not appreciably 

affect nitrate concentrations.

The maximum concentration of 

nitrate in the monitoring wells was 

8 mg/L, which is less than the USEPA 

drinking-water standard for nitrate 

(10 mg/L). Although most drinkingwater-supply wells in the Mississippian 

carbonate aquifer are completed in 

bedrock and do not withdraw water from 

shallow depths, shallow ground water 

moves downward through conduits in 

the bedrock and can affect the quality of 

drinking water in the aquifer.

Nitrate Concentrations 

Decrease in Ground Water and 

Base Flow During Summer and 

Fall

Nitrate concentrations in ground 

water decrease during summer and fall 

months (fig. 12); thus, the transport of 

nitrate to streams decreases at a time 

when streams are at greatest risk of 

eutrophication. The seasonal variation 

of nitrate in the Mississippian carbonate 

aquifer is illustrated by concentration 

data from Meridianville Spring. Lower 

nitrate concentrations in ground water 

during the summer likely are caused 

by decreased transport of nitrate from 

the land surface to the aquifer, resulting 

from increased uptake of soil nitrogen 

by plants. Nitrate concentrations during 

base flow in nearby Hester Creek follow 

a similar pattern of decreasing in the late 

summer and fall during periods of base 

flow when ground water is the primary 

source of nitrate to the stream.

Nitrate Concentrations in 

Drinking Water Generally 

Were Below Level of Concern

Ground water in the Lower Tennessee River Basin generally is safe to 

drink with respect to nitrate. Nitrate 

concentrations in the Mississippian and 

Ordovician carbonate aquifers were 

less than the USEPA drinking-water 

standard of 10 mg/L in 71 of the 73 

wells sampled. Point sources may have 

contributed to the elevated nitrate concentrations, which exceeded the USEPA 

drinking-water standard for nitrate, in 

the other two wells. In addition, nitrate 

concentrations in about 70 percent of the 

springs and wells in the Mississippian 

and Ordovician carbonate aquifers were 

less than the 2–mg/L threshold, indicating background levels.

The median nitrate concentration for wells in the Ordovician 

carbonate aquifer was lower (less than 

0.2 mg/L) than the median concentration 

for springs in the same aquifer (1.2 mg/

L) (fig. 13). Nitrate can be removed by 

denitrification in aquifers with low dissolved-oxygen concentrations, and the 

median dissolved-oxygen concentration 

for wells in the Ordovician carbonate 

aquifer was less than 1 mg/L, compared 

to 8 mg/L for the springs.

Figure 12. Nitrate concentrations in ground 

water and in base-flow samples from 

Hester Creek have similar seasonal variations. Decreases in the summer probably 

relate to uptake of soil nitrogen by plants, 

resulting in less transport of nitrate to 

the Mississippian carbonate aquifer and, 

subsequently, into streams.

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10

15

2.5

7.5

12.5

17.5

20

NITRATE CONCENTRATION, IN MILLIGRA

MS PER LITER

Public and

domestic supply

wells

MISSISSIPPIAN

CARBONATE

AQUIFER

ORDOVICIAN

CARBONATE

AQUIFER

Springs

USEPA drinkingwater standard

Shallow

monitoring wells

Public and

domestic supply

wells

Median

Figure 13. Nitrate concentrations in almost 

all wells and springs sampled in the Lower 

Tennessee River Basin were below the 

USEPA drinking-water standard.

Additional Information

For additional information on 

nutrients in the Lower Tennessee 

River Basin, refer to Hoos and 

others (2000), Woodside and Hoos 

(2001), Kingsbury and Shelton 

(2002), and Kingsbury (2003).

These reports are available at 

http://water.usgs.gov/pubs/wri/

wri994139, http://water.usgs.gov/

pubs/FS/fs02501, http://water. 

usgs.gov/pubs/wri/wri024083, and 

http://water.usgs.gov/pubs/wri/

wri034181
Nutrients 15

 Mean annual nitrate concentrations in 

Hester, North Fork, and Cane Creeks, which drain 

agricultural land, are below the national median for 

79 agricultural streams sampled nationwide as part 

of the NAWQA Program. Mean annual nitrate 

concentration in Scarham Creek, which drains an 

area with a high density of poultry-feeding 

operations, is slightly higher than the national 

median. Mean annual nitrate concentrations in the 

Flint, Elk, and Duck Rivers, which drain basins 

with mixed land uses, are similar to concentrations 

in agricultural streams in the Lower Tennessee 

River Basin and are similar to or above the national 

median for rivers with mixed land use.

The median nitrate concentration in shallow 

agricultural monitoring wells in the Mississippian carbonate aquifer is below the national median in about 1,440 

agricultural monitoring wells sampled nationwide as part of 

the NAWQA Program, whereas the median concentration 

for public and domestic supply wells in the Mississippian 

carbonate aquifer is above the national median. The low 

concentrations of nitrate in public and domestic supply wells 

in the Ordovician carbonate aquifer (median value 0.2 mg/L) 

may be related to the instability of nitrate in this aquifer. Dissolved-oxygen concentrations in wells in this aquifer were 

low (median below 1 mg/L), resulting in conditions favorable 

for denitrification. 

NITRATE CONCENTRATIONS IN STREAMS AND GROUND 

WATER GENERALLY ARE SIMILAR TO THE NATIONAL MEDIAN

In streams, rivers, and lakes, elevated concentrations 

of nutrients can stimulate nuisance growth of algae. As 

the algae decay, dissolved oxygen is depleted, thereby 

affecting fish and other aquatic life.

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16 Water Quality in the Lower Tennessee River Basin

Pesticides in Surfaceand Ground-Water 

Resources

About 3.7 million pounds of pesticides were applied to cropland in the 

Lower Tennessee River Basin in 1992 

(Kingsbury and others, 1999). Six pesticides (atrazine, monosodium methanearsonate (MSMA), 2,4-D, metolachlor, 

methyl parathion, and fluometuron) 

accounted for about 42 percent of the 

total amount of pesticides applied in the 

basin. Almost half of the agricultural 

pesticides used in the basin are applied 

to crops, such as cotton, corn, and 

soybeans, in the Eastern Highland Rim, 

which is underlain by the Mississippian 

carbonate aquifer.

Although pesticide concentrations 

in surface- and ground-water resources 

in the Lower Tennessee River Basin 

infrequently exceeded standards and 

guidelines to protect human health and 

aquatic life, mixtures of pesticides were 

frequently detected. The effects of longterm exposure to mixtures of pesticides 

at low concentrations are poorly understood; thus, it is important to understand 

the fate of pesticides in the environment.

Pesticides Were Commonly 

Detected in Streams and 

Rivers

Fifty-two pesticides, including 38 

herbicides, 11 insecticides, and 3 fungicides, were detected in streams and 

rivers in the Lower Tennessee River 

Basin. The herbicides atrazine (applied 

to corn) and metolachlor (applied to 

soybeans) were detected in more than 

89 percent of the samples (fig. 14). 

Other herbicides frequently detected 

include fluometuron and norflurazon, 

which are applied to cotton, and prometon and tebuthiuron, commonly applied 

to control vegetation along highway 

and railroad rights-of-way. Insecticides 

applied in agricultural and urban areas, 

such as diazinon, malathion, and carbofuran, were detected in less than 

16 percent of the samples.

Although pesticides were frequently detected, aquatic-life guidelines 

were exceeded in less than 6 percent 

of the 134 samples. Pesticides that 

exceeded aquatic-life guidelines include 

atrazine, cyanazine, and malathion; 

however, no aquatic-life guidelines have 

been established for 31 of the 52 pesticides detected.

Pesticides Detected Vary with 

Streamflow and Season

 The mixtures of pesticides detected 

in streams and rivers varied with streamflow conditions and season. The largest 

numbers of pesticides (as many as 25 

pesticides in one sample) and the highest 

pesticide concentrations in Hester Creek 

and the Flint River were detected during 

the growing season following a storm 

(fig. 15).

In Hester Creek and the Flint River, 

two or more pesticides were detected in 

every sample collected during base-flow 

conditions when there was no surface 

runoff, indicating transport of some pesticides through the ground-water system. 

The number of pesticides detected in 

base-flow samples from Hester Creek 

decreased from eight or more early in 

the growing season to fewer than four 

during the fall and winter (fig. 15). In 

contrast, base-flow samples from the 

Flint River generally contained eight 

or more pesticides throughout the year 

with little seasonal variability. The differences in the numbers of pesticides 

in base-flow samples between Hester 

Creek and the Flint River likely are the 

result of differences in average residence 

times of ground water in these basins. 

The decrease in the number of pesticides in base-flow samples from Hester 

Creek in the fall and winter suggests that 

ground-water flow paths are relatively 

short. The high number of pesticides 

detected in base-flow samples from the 

Flint River throughout the year suggests 

longer ground-water flow paths and 

indicates that pesticides applied during 

the growing season persist in the aquifer 

throughout the year.

Pesticides

Figure 14. Herbicides were detected at 

higher concentrations and more frequently 

than insecticides in streams and rivers in 

the Lower Tennessee River Basin.

Figure 15. Although a large number of 

pesticides were detected in surface 

water during the early part of the growing 

season, a small number of pesticides were 

present throughout the year.

0 20 40 60 80 100

CARBOFURAN

MALATHION

DIAZINON

TEBUTHIURON

PROMETON

NORFLURAZON

SIMAZINE

FLUOMETURON

METOLACHLOR

ATRAZINE

0 4 8 25

DETECTION FREQUENCY,

IN PERCENT

MAXIMUM PESTICIDE CONCENTRATION,

IN MICROGRAMS PER LITER

MAXIMUM CONCENTRATION

HERBICIDE

INSECTICIDE

EXPLANATION

BASE FLOW

(during and up to 6

days following a storm)

STORMFLOW

J F M A M J J A S O N D

1999

0

4

8

12

16

20

24

0

4

8

12

16

20

24

FLINT RIVER

HESTER CREEK

NUMBER OF PESTICIDES DETECTED IN A SAMPLE

Growing season

Growing season
Pesticides 17

Pesticides Were Detected 

at Low Concentrations in 

Carbonate Aquifers

Although one or more pesticides 

were detected in about 60 percent of 

the wells and springs sampled in the 

Mississippian and Ordovician carbonate aquifers, 95 percent of the pesticide 

concentrations were less than 0.5 μg/L, 

well below drinking-water standards. 

Little is known, however, about the 

potential health effects of exposure to 

low levels of multiple pesticides. Thirtyfive pesticides, including 28 herbicides, 

6 insecticides, and 1 fungicide, were 

detected in wells and springs sampled 

in the Mississippian and Ordovician 

carbonate aquifers. The most frequently 

detected pesticides were atrazine and 

deethylatrazine, a degradation product 

of atrazine. Five or more pesticides were 

detected in 19 percent of the wells in the 

Mississippian carbonate aquifer and in 

10 percent of the wells in the Ordovician 

carbonate aquifer (fig. 16). 

None of the pesticides detected in 

the carbonate aquifers exceeded drinking-water standards; however, a human 

health benchmark was exceeded for 

dieldrin, a potentially carcinogenic 

insecticide. Dieldrin was detected in 

19 percent of the wells in the Mississippian carbonate aquifer, and concentrations exceeded 0.02 μg/L, the riskspecific dose for a cancer-risk level of 

1 in 100,000 (U.S. Environmental 

Protection Agency, 2002a), in about 13 

percent of the wells.

Prior to being banned in 1984, 

dieldrin was used as an insecticide on 

cotton and as a termiticide in homes. 

The lack of detections of dieldrin in 

shallow agricultural monitoring wells in 

the Mississippian carbonate aquifer is an 

indication that dieldrin residues associated with termite treatments are a likely 

source of this insecticide rather than 

residues associated with cotton cultivation.

Carbonate Aquifers Are 

Vulnerable to Nonpoint-Source 

Contamination

Pesticides detected in the carbonate aquifers reflect differences in land 

use in the Eastern Highland Rim and in 

the Inner and Outer Nashville Basins. 

General-use pesticides that are applied 

along road and powerline rights-of-way 

and in urban areas to control woody 

vegetation and weeds (tebuthiuron and 

prometon) were detected at similar 

frequencies in wells in both carbonate 

aquifers (fig. 17). Agricultural pesticides 

were detected more frequently in the 

Mississippian carbonate aquifer than in 

the Ordovician carbonate aquifer. In the 

Ordovician carbonate aquifer, atrazine 

was the only agricultural pesticide 

detected in more than 9 percent of the 

samples (three detections, fig. 17). In 

contrast, eight pesticides were detected 

in 9 percent or more of samples from the 

Mississippian carbonate aquifer. Several 

of these pesticides, such as the herbicide 

fluometuron (fig. 17), are used on cotton 

and were detected in less than 3 percent 

of the samples from the Ordovician carbonate aquifer. Only a small amount of 

cotton (about 4,000 acres) is cultivated 

in the Inner and Outer Nashville Basin 

(Kingsbury and others, 1999).

TN

AL

WELLS SPRINGS

5 or more

NUMBER OF PESTICIDES DETECTED

No Detections

1 to 2

3 to 4

EXPLANATION

EASTERN HIGHLAND RIM

MISSISSIPPIAN CARBONATE AQUIFER

INNER AND OUTER NASHVILLE BASIN

ORDOVICIAN CARBONATE AQUIFER

0 10 30 50 KILOMETERS

0 10 20 30 40 50 MILES

20 40

Figure 16. Pesticide mixtures were more prevalent in wells in the Eastern Highland Rim, 

which is about 16 percent cropland, than in wells in the Inner and Outer Nashville Basin, 

which is about 4 percent cropland.

Figure 17. Pesticides that are used predominantly on cropland were detected 

more frequently in samples from wells 

in the Mississippian carbonate aquifer, 

whereas noncropland pesticides were 

detected at similar frequencies in both 

aquifers. 

ORDOVICIAN

CARBONATE

AQUIFER

WELLS WELLS

DETEC

TIO

N FREQ

UEN

C

Y,

IN PER

CEN

T

ATRAZINE

FLUOMETURON

PROMETON

TEBUTHIURON

EXPLANATION

CROPLAND USE NONCROPLAND USE

MISSISSIPPIAN

CARBONATE

AQUIFER

0

20

40

60
18 Water Quality in the Lower Tennessee River Basin

corn, and soybeans). Although detection frequencies were somewhat higher 

in the shallow agricultural monitoring 

wells than in the deep wells used for 

drinking-water supply in the Mississippian carbonate aquifer, the same 

pesticides were detected 

frequently and at comparable concentrations in both well networks (fig. 

18). Detection of the same pesticides 

in both types of wells is probably the 

result of the karst hydrology of the 

Mississippian aquifer, which increases 

the transport of nonpoint-source 

contaminants away from agricultural 

areas. 

Pesticide Degradates Were 

Detected in Surface and 

Ground Water 

 Knowledge of the occurrence of 

pesticide degradates in the hydrologic 

system is important in understanding the 

fate of pesticides in the environment. 

Pesticides typically are designed to 

degrade in a few days or weeks after 

application. Some pesticides, such 

as aldicarb, degrade into compounds 

that are about as toxic as the original 

pesticide. For most pesticide degradates, 

the long-term effects on human health 

and aquatic life generally are not well 

understood. 

Degradates of atrazine, fluometuron 

(fig. 19), norflurazon, and aldicarb were 

detected frequently in surface water and 

ground water in the Eastern Highland 

Rim. In surface water, degradate concentrations varied seasonally. Concentrations were highest in the spring, similar 

to the seasonal variation in concentration of the parent pesticides. Detection of degradates generally coincided 

with detection of the parent pesticide, 

except for aldicarb. Aldicarb degradates 

were detected frequently in surface 

and ground water at concentrations 

less than 0.5 μg/L; however, aldicarb 

was detected in only one ground-water 

sample (fig. 19).

Shallow monitoring wells installed near 

agricultural fields and deeper wells that 

supply drinking water throughout the 

Eastern Highland Rim were sampled to 

describe the quality of water in the Mississippian carbonate aquifer.

Figure 19. Pesticides and their degradates 

were detected in surface water and in 

shallow ground water.

Figure 18. Pesticides detected in shallow 

monitoring wells also were detected in 

public- and domestic-supply wells in the 

Mississippian carbonate aquifer. 

The detection of similar pesticides 

in shallow and deep wells in the Mississippian carbonate aquifer indicates that 

the aquifer is vulnerable to nonpointsource contamination (fig. 18). Shallow 

agricultural monitoring wells (generally 

less than 60 feet deep) were installed 

near agricultural fields throughout the 

Eastern Highland Rim to characterize 

the quality of water in the Mississippian 

carbonate aquifer that is most likely to 

be affected by agricultural land uses 

(primarily the production of cotton, 

DETECTION FREQUENCY,

IN PERCENT

SHALLOW MONITORING WELLS

PUBLIC AND DOMESTIC SUPPLY WELLS

EXPLANATION

0 20 40 80

ATRAZINE

FLUOMETURON

NORFLURAZON

ALDICARB

SULFOXONE

METOLACHLOR

60 100

0.01 0.1 1 10

MAXIMUM CONCENTRATION

MAXIMUM CONCENTRATION,

IN MICROGRAMS PER LITER

Shallow

monitoring

wells

Flint River

Atrazine

*Fluometuron

*Data censored at 0.05

microgram per liter

Aldicarb

Atrazine

Deethylatrazine

*Fluometuron

*Demethylfluometuron

Aldicarb

Aldicarb sulfone

Deethylatrazine

*Demethylfluometuron

Aldicarb sulfone

DETECTION FREQUENCY,

IN PERCENT

PESTICIDE DEGRADATE

PESTICIDE

0 20 40 60 80 100

0.001 0.01 0.1 1 10

MAXIMUM CONCENTRATION

MAXIMUM CONCENTRATION,

IN MICROGRAMS PER LITER

EXPLANATION

Additional Information

For additional information on 

pesticides in surface- and groundwater resources in the Lower Tennessee River Basin, refer to Hoos 

and others (2002), Kingsbury and 

Shelton (2002), and Kingsbury 

(2003). 

These reports are available at 

http://water.usgs.gov/pubs/wri/ 

wri014185, 

http://water.usgs.gov/pubs/wri/

wri024083, and 

http://water.usgs.gov/pubs/wri/

wri034181
Pesticides 19

PESTICIDE DETECTIONS IN THE LOWER TENNESSEE RIVER 

BASIN WERE HIGHER THAN NATIONAL RESULTS

Pesticides frequently detected in surface and ground 

water in the Lower Tennessee River Basin generally are 

similar to those frequently detected throughout the Nation. 

Atrazine is among the pesticides with the highest estimated use in the Lower Tennessee River Basin and across 

the Nation and was detected in more than 90 percent of 

the samples collected from agricultural streams both in the 

Lower Tennessee River Basin and nationwide. Sixty-two 

percent of the agricultural monitoring wells in the Lower 

Tennessee River Basin contained atrazine, compared to 

40 percent of the agricultural monitoring wells across the 

Nation. 

Herbicides applied to cotton, fluometuron and norflurazon, were detected more frequently in Hester Creek, the 

Flint River, and in ground water in the Eastern Highland 

Rim than nationwide. This probably is because cotton 

cultivation is limited to small geographic areas throughout 

the Nation. However, fluometuron was detected in the 

Flint River at higher frequencies compared to a subset 

of 34 basins across the Nation with cotton cultivation 

and fluometuron use. The instream detection frequency 

of fluometuron for the Flint River, relative to the amount 

applied in the basin and normalized by drainage area, was 

second to the highest among the subset of 34 basins across 

the Nation.

The occurrence of pesticides in surface water and 

ground water is related not only to the amounts applied 

but also to physical and chemical properties controlling 

pesticide mobility in the environment. In the Lower 

Tennessee River Basin, several pesticides, such as atrazine 

and fluometuron, were detected both in ground-water and 

base-flow samples, indicating pesticide movement into 

and through the ground-water system. Other pesticides, 

such as cyanazine, were detected in storm samples from 

streams but typically were not detected in ground-water or 

base-flow samples. Estimates of the half-life of cyanazine 

are only about 10 percent as long as the half-life of 

atrazine, suggesting that cyanazine breaks down more 

rapidly than atrazine; thus, the transport of cyanazine to 

ground water is negligible.

Although thousands of pounds of pesticides are 

applied to cropland annually, sorption of pesticides to 

soils and degradation by microbes, sunlight, and chemical reactions reduce the amount of pesticides that can be 

washed into streams and rivers. The amounts of atrazine, 

metolachlor, fluometuron, and norflurazon transported 

from cropland to the Flint River and Hester Creek ranged 

from 3 to 5 percent of the estimated amount applied (Hoos 

and others, 2002). These herbicides are applied to the soil 

before crops emerge, thus increasing the likelihood of 

transport in surface runoff. 

0 100 0 100

EASTERN

HIGHLAND RIM

Agricultural land use

(32 monitoring wells)

NATIONWIDE

Agricultural land use

(approx. 1,440

monitoring wells)

FLINT RIVER

Mixed

land use

0 100 0 100

HESTER CREEK

Agricultural

land use

Fluometuron

Metolachlor

0 100

NATIONWIDE

Agricultural

streams (79)

Atrazine

Deethylatrazine

Simazine

Data not censored

SURFACE WATER GROUND WATER

Prometon

Norflurazon

Aldicarb

sulfoxide < 1% < 1%

COTTON

CORN

OTHER

USES

SOYBEANS

AND CORN

Cyanazine

< 1%

DETECTION FREQUENCY,

IN PERCENT

DETECTION FREQUENCY,

IN PERCENT

Pesticides applied to corn, 

cotton, and soybeans were 

frequently detected in Hester 

Creek, the Flint River, and in 

shallow monitoring wells in 

the Mississippian carbonate 

aquifer.
20 Water Quality in the Lower Tennessee River Basin

VOCs Were Detected at 

Low Concentrations in 

Carbonate Aquifers

Volatile organic compounds 

(VOCs) are a water-quality concern 

because of their widespread use, toxicity, and documented presence at low 

concentrations in ground water across 

the Nation (Squillace and others, 1999). 

Paints, solvents, fuels, refrigerants, 

fumigants, and fuel additives contain 

VOCs. Many VOCs, such as the drycleaning solvent PCE, are known or 

suspected carcinogens.

 VOCs were detected in about 67 

percent of the wells and springs sampled 

in the Mississippian and Ordovician 

carbonate aquifers in the Lower Tennessee River Basin. Although VOCs were 

detected frequently, 70 percent of the 

detections were less than 0.2 μg/L, 

which is at least 20 times less than 

drinking-water standards for most 

VOCs. Eleven of the 29 VOCs detected 

in the carbonate aquifers have drinkingwater standards. Concentrations of 

VOCs equaled or exceeded drinkingwater standards in only two wells. PCE 

and TCE, both of which have a drinkingwater standard of 5 μg/L (U.S. Environmental Protection Agency, 2002b), were 

detected at 7.5 and 5 μg/L, respectively. 

Although 29 VOCs were detected, 13 

VOCs were detected only once, and 

most were in one well in the Ordovician 

carbonate aquifer, where natural 

deposits of crude oil and natural gas may 

be a source of VOCs in ground water.

Carbonate Aquifers Are 

Vulnerable to Contamination

VOCs detected in carbonate aquifers in the Lower Tennessee River Basin 

were similar to those detected in major 

aquifers across the Nation; however, 

detection frequencies were higher in the 

Mississippian carbonate aquifer 

(fig. 20). The karst hydrology of this 

aquifer, with numerous sinkholes and 

other karst landforms, likely increases 

the probability of ground-water contamination. Springs are particularly susceptible to nearby sources of contamination 

on the surface. VOCs were detected 

more frequently in springs than in wells 

in the Ordovician carbonate aquifer.

Detection of VOCs Is Related to 

Population Density

VOCs are prevalent nationwide in 

shallow aquifers near urban areas (Squillace and others, 1999). This also is true 

in the Lower Tennessee River Basin. 

VOCs were detected in 80 percent of 

the wells sampled in the Mississippian 

carbonate aquifer and in 55 percent of 

the wells and 70 percent of the springs 

sampled in the Ordovician carbonate 

aquifer. The Eastern Highland Rim, 

which overlies the Mississippian carbonate aquifer, had about 170 people per 

square mile in 1995, compared to about 

70 people per square mile in the Inner 

and Outer Nashville Basins, which overlie the Ordovician carbonate aquifer.

Volatile Organic Compounds

Figure 20. Volatile organic compounds were detected more frequently in the 

Mississippian carbonate aquifer than in the Ordovician carbonate aquifer and 

across the Nation.

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Numerous roadside springs throughout 

the Lower Tennessee River Basin are 

commonly used for drinking water even 

though springs are susceptible to nearby 

sources of contamination.
 21

Figure 21. Although the use of DDT was banned in 1973, residues of DDT are detected 

frequently in fish tissue at sites throughout the Lower Tennessee River Basin.

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guideline for the protection of fisheating wildlife at four sites. 

PCBs were developed more than 

120 years ago for use as lubricants, 

heat-transfer agents, and flame retardants in electrical components. In 1979, 

the use of PCBs was restricted primarily 

to totally enclosed systems. PCBs were 

detected in whole fish and fish fillets 

at 78 percent of the sites sampled from 

1985 to 1998 in the basin. The U.S. 

Food and Drug Administration (2003) 

temporary tolerance level of 2,000 μg/kg 

for concentrations of PCBs in fish fillets 

was exceeded at six sites along the main 

stem of the Tennessee River. At two 

sites, PCBs in whole fish exceeded the 

110–μg/kg guideline to protect fisheating wildlife (Newell and others, 

1987).

DDT and PCBs Persist in 

Fish Tissue

Although uses of DDT and PCBs 

were discontinued more than 20 years 

ago, residues of these compounds 

continue to be detected in fish tissue 

throughout the Lower Tennessee River 

Basin. DDT and PCBs are stored in fatty 

tissue and are slow to degrade, resulting 

in bioaccumulation of these compounds 

in fish. 

DDT was used as an insecticide in 

urban and agricultural areas, with peak 

usage in the United States occurring in 

the early 1960s. The use of DDT was 

discontinued in the United States in 

1973, except during public health emergencies. Prior to 1973, DDT was applied 

in the basin primarily to cotton fields 

Fish Tissue

to control insects, and to wetlands, 

marshes, and reservoirs to prevent 

the occurrence of mosquitoes and 

the spread of malaria.

DDT and PCBs were detected 

frequently in whole fish and fish 

fillets in samples collected by State 

and Federal agencies from 1980 to 

1998; however, less than 3 percent 

of the sites had concentrations that 

exceeded human health action levels 

or wildlife guidelines (Knight and 

Powell, 2001). Specifically, DDT 

and its degradation products DDD 

and DDE were detected either singly 

or in combination at 136 of 144 

sites in the basin. The human health 

action level for total DDT in fish 

fillets was exceeded at four sites 

(fig. 21). Total DDT concentrations 

in whole fish also exceeded the 

In addition to agricultural uses, DDT also 

was applied to wetlands, marshes, and 

reservoirs in the Lower Tennessee River 

Basin to control mosquito populations and 

prevent the spread of malaria.

Courtesy of the Tennessee Valley Authority Historic 

Collection, 1938

Additional Information

For a detailed description of the 

occurrence and distribution of 

pesticides and trace elements in 

fish tissue in the Lower Tennessee 

River Basin, refer to Knight and 

Powell (2001). 

The report is available at 

http://water.usgs.gov/pubs/wri/

wri014184
22 Water Quality in the Lower Tennessee River Basin

Study Unit Design

The Lower Tennessee River Basin Study Unit design 

blends an assessment of local water-quality issues within a 

nationally consistent design structure that incorporates a multiscale, interdisciplinary approach consisting of stream chemistry, 

stream ecology, and ground-water chemistry (Gilliom and others, 1995). Surface-water, ecological, and ground-water studies focused primarily on the Inner and Outer Nashville Basins 

and the Eastern and Western Highland Rims. Karst landforms, 

such as caves, sinkholes, and springs, in these areas increase the 

vulnerability of surface- and ground-water resources to contamination.

Stream Chemistry and Ecology

Stream-chemistry assessments focused on how water quality varies in rivers and streams in relation to land use and natural 

setting—a combination of geology, soils, and physiography. 

The quality of water in the Duck, Elk, and Flint Rivers reflects 

a complex mixture of land uses and natural settings. The quality 

of water in the four selected streams (North Fork Creek, Cane 

Creek, Hester Creek, and Scarham Creek) represents the effects 

of mostly agricultural land uses, both pastureland and cropland, 

within distinct, relatively homogeneous natural settings.

Ecological assessments focused primarily on describing 

how fish, invertebrate, and algal communities and instream 

habitat vary in relation to land use throughout the Eastern and 

Western Highland Rim.

Ground-Water Chemistry

Ground-water assessments focused on carbonate aquifers underlying the Eastern Highland Rim and the Inner and 

Outer Nashville Basin. These aquifers are important sources 

of drinking water for public water systems and domestic uses 

in rural areas. These aquifers also are vulnerable to contamination because of the karst landforms. Domestic wells and springs 

were sampled to characterize the water quality of the carbonate 

aquifers. Shallow monitoring wells, installed in or near cotton, 

corn, or soybean fields, were sampled to characterize the effects 

of agriculture on recently recharged ground water in the Eastern 

Highland Rim.

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

EXPLANATION

COASTAL PLAIN

WESTERN HIGHLAND RIM TRANSITION

OUTER NASHVILLE BASIN

INNER NASHVILLE BASIN

EASTERN HIGHLAND RIM

CUMBERLAND PLATEAU

PLATEAU ESCARPMENT AND

VALLEYS

VALLEY AND RIDGE

RIVER SITE

STREAM SITE

ECOLOGICAL SAMPLING SITE

KENTUCKY

88

87

86

o

o

o

36o

35

o

Duck

River

Elk River

Clar ks River Buffalo

Sho a l Creek

Bear

Creek

Flint

Paint

R ockRi v er

Beech River

Sequatchie River

River

Kentucky

Lake

Wheeler Lake

Wilson Lake

Pickwick L ake

Tennessee River

Normandy Lake

Tims Ford

Lake

Nickajack Lake

Guntersville Lake

Big Sandy River

TENNESSEE

GEORGIA

TENNESSEE

ALABAMA

MISSISSIPPI

Town Creek

KENTUCKY

88

87

86

o

o

o

36o

35

o

TENNESSEE

GEORGIA

TENNESSEE

ALABAMA

MISSISSIPPI

EXPLANATION

GROUND-WATER CHEMISTRY

STREAM CHEMISTRY AND ECOLOGY

EXPLANATION

WELLS IN MISSISSIPPIAN CARBONATE AQUIFER

SPRINGS IN MISSISSIPPIAN CARBONATE AQUIFER

LAND-USE MONITORING WELLS

WELLS IN ORDOVICIAN CARBONATE AQUIFER

SPRINGS IN ORDOVICIAN CARBONATE AQUIFER

Duck River

North Fork Creek

Scarham

Creek

Cane Creek

Elk River Hester Flint River

Creek

(03603000)

(03598250)

(035825882)

(03575100) (03573182)

(0357479650) (03584600)

(USGS STATION NUMBER)

Additional Information

Additional information on water-quality conditions 

in the Lower Tennessee River Basin is available at 

http://tn.water.usgs.gov/lten/tenn.html

Water-quality data and collection and analytical methods 

can be accessed at http://water.usgs.gov/nawqa
Study Unit Design 23

Study

component What data were collected and why Types of sites sampled

Number 

of sites 

sampled

Sampling 

frequency and 

period

Stream Chemistry

Bottom

sediment

Trace metals, organochlorine pesticides, PCBs, and 

semivolatile organic compounds were measured 

in bottom sediment collected from depositional 

zones to assess the presence of potentially toxic 

compounds.

Rivers and streams draining a mixture 

of land uses with drainage areas ranging 

from 29.3 to 2,557 square miles

14 Once,

1998.

Rivers Major ions, nutrients, organic carbon, bacteria, and 

suspended sediment were measured to describe 

seasonal variations of concentrations and loads in 

rivers draining a mixture of land uses and subunits.

Duck River (2,557 square miles),

Elk River (1,805 square miles) 

2 Monthly and 

storm events,

1999–2000.

Streams Major ions, nutrients, organic carbon, bacteria, and 

suspended sediment were measured to describe 

seasonal variations of concentrations and loads 

in streams draining pasture and cultivated land in 

three subunits (fig. 1).

Cane Creek, Outer Nashville Basin (78.8 

square miles); North Fork Creek, Inner 

Nashville Basin (74.1 square miles); 

Scarham Creek, Cumberland Plateau 

(54.4 square miles)

3 Monthly and 

storm events,

1999–2001.

Pesticides— in 

rivers and 

streams

Pesticides, major ions, nutrients, organic carbon, 

bacteria, and suspended sediment were measured 

to determine short-term temporal variations in 

concentrations and loads.

Flint River (374 square miles),

Hester Creek (29.3 square miles);

Both basins located in the Eastern 

Highland Rim

2 Biweekly,

Mar.–Nov. 2000;

monthly and 

storm events,

1999–2001.

Stream Ecology

Fish tissue Organochlorine pesticides, PCBs, and trace elements in fish tissue were measured to assess the 

presence of potentially toxic compounds.

Rivers and streams draining a mixture 

of land uses with drainage areas ranging 

from 29.3 to 447 square miles

10 Aug.–Sept.

1998.

Streams Aquatic communities (fish, macroinvertebrates, 

and algae) and stream habitat were measured to 

describe aquatic communities in four subunits 

(fig. 1) in the basin.

Cane Creek, Outer Nashville Basin;

North Fork Creek, Inner Nashville Basin; 

Scarham Creek, Cumberland Plateau; 

Hester Creek, Eastern Highland Rim

4 Annually,

1999–2001.

Land use—

agricultural

Aquatic communities (fish, macroinvertebrates, 

and algae), stream habitat, nutrients, bacteria, and 

streamflow were measured to assess the effects of 

agricultural land use on aquatic communities.

Streams in the Eastern Highland Rim,

Streams in the Western Highland Rim

20,

17

Once,

1999;

2000–2001.

Ground-Water Chemistry

Carbonate 

aquifer 

survey

Major ions, nutrients, dissolved organic carbon, 

trace metals, pesticides, volatile organic compounds, bacteria, and radon were measured to 

describe the quality of water in the Mississippian 

aquifer.

Domestic and public-supply wells, 

ranging in depth from 38 to 157 feet, distributed throughout the Eastern Highland 

Rim

32 wells Once,

June–July 1999.

Springs—

temporal 

variability

Discharge, major ions, dissolved organic carbon, 

pesticides, and bacteria were measured to describe 

the temporal variability in ground-water quality in 

the Mississippian aquifer.

Springs located in the Eastern Highland Rim — Meridianville Spring and 

McGeehee Spring

2 springs Bimonthly, 

Apr. 1999 – Feb. 

2000;

monthly, 

Mar. 2000–2001.

Land use—

agricultural

Major ions, nutrients, dissolved organic carbon, 

pesticides, and bacteria were measured to assess 

the effects of agriculture on the quality of shallow 

ground water in the Mississippian aquifer.

Monitoring wells, ranging in depth 

from 14 to 79 feet, installed at randomly 

selected sites in agricultural areas in the 

Eastern Highland Rim

28 wells,

4 wells

Once,

May–June 2000;

April 2001.

Carbonate 

aquifer 

survey

Major ions, nutrients, dissolved organic carbon, 

trace metals, pesticides, volatile organic compounds, bacteria, and radon were measured to 

describe the quality of water in the Ordovician 

aquifer.

Domestic and public-supply wells, ranging in depth from 22 to 300 feet, and 

springs distributed throughout the Inner 

and Outer Nashville Basins

31 wells,

10 

springs

Once,

Sept.–Oct. 2000.
24 Water Quality in the Lower Tennessee River Basin

References

The Lower Tennessee River Basin publications are shown 

in bold type.

Alabama Department of Environmental Management, 2002, 

Alabama’s draft 2002 section 303(d) list fact sheet: Alabama Department of Environmental Management, accessed 

September 30, 2002, at URL http://www.adem.state.al.us/

WaterDivision/WQuality/303d/Draft02303(d)List.pdf

Alexander, R.B., Smith, R.A., and Schwarz, G.E., 2000, Effect 

of stream channel size on the delivery of nitrogen to the 

Gulf of Mexico: Nature, v. 403, p. 758–761.

Cuffney, T.F., 2003, User’s manual for the National WaterQuality Assessment Program invertebrate data analysis 

system (IDAS) software version 3: U.S. Geological Survey 

Open-File Report 03–172, 103 p.

Curriero, F.C, Patz, J.A., Rose, J.B., and Subhash, L., 2001, 

The association between extreme precipitation and waterborne disease outbreaks in the United States, 1948–94: 

American Journal of Public Health, v. 91, no. 8, p. 1194–

1199.

Gilliom, R.J., Alley, W.M., and Gurtz, M.E., 1995, Design of 

the National Water-Quality Assessment Program—Occurrence and distribution of water-quality conditions: U.S. 

Geological Survey Circular 1112, 33 p.

Griffith, G.E., Omernik, J.M., and Azevedo, S.H., 1997, 

Ecoregions of Tennessee: U.S. Environmental Protection Agency National Health and Environmental Effects 

Research Laboratory, EPA/600/R–97/022, 51 p.

Hoos, A.B., Robinson, J.A., Aycock, R.A., Knight, R.R., 

and Woodside, M.D., 2000, Sources, instream transport, 

and trends of nitrogen, phosphorus, and sediment in the 

lower Tennessee River Basin, 1980–96: U.S. Geological 

Survey Water-Resources Investigations Report 99–4139, 

96 p.

Hoos, A.B., Garrett, J.W., and Knight, R.R., 2002, Water 

quality of the Flint River Basin, Alabama and Tennessee, 1999–2000: U.S. Geological Survey Water-Resources 

Investigations Report 01–4185, 37 p.

Johnson, G.C., 2002, Water quality of springs in the Valley 

and Ridge Physiographic Province in the upper Tennessee River Basin, 1997: U.S. Geological Survey WaterResources Investigations Report 02–4180, 24 p.

Kingsbury, J.A., 2003, Shallow ground-water quality in 

agricultural areas of northern Alabama and middle 

Tennessee, 2000–2001: U.S. Geological Survey WaterResources Investigations Report 03–4181, 38 p.

Kingsbury, J.A., Hoos, A.B., and Woodside, M.D., 1999, 

Environmental setting and water-quality issues in the 

lower Tennessee River Basin: U.S. Geological Survey 

Water-Resources Investigations Report 99–4080, 44 p.

Kingsbury, J.A., and Shelton, J.M., 2002, Water quality of 

the Mississippian carbonate aquifer in parts of middle 

Tennessee and northern Alabama, 1999: U.S. Geological 

Survey Water-Resources Investigations Report 02–4083, 

36 p.

Knight, R.R., and Powell, J.R., 2001, Occurrence and distribution of organochlorine pesticides, polychlorinated 

biphenyls, and trace elements in fish tissue in the lower 

Tennessee River Basin, 1980–98: U.S. Geological Survey 

Water-Resources Investigations Report 01–4184, 32 p.

Masters, L.L., Flack, S.R., and Stein, B.A., eds., 1998, Rivers 

of life—Critical watersheds for protecting freshwater biodiversity: Arlington, Va., The Nature Conservancy, 71 p.

Mueller, D.K., Hamilton, P.A., Helsel, D.R., Hitt, K.J., and 

Ruddy, B.C. 1995, Nutrients in ground water and surface 

water of the United States—An analysis of data through 

1992: U.S. Geological Survey Water-Resources Investigations Report 95–4031, 74 p.

Newell, A.J., Johnson, D.W., and Allen, L.K., 1987, Niagara 

River biota contamination project—Fish flesh criteria for 

piscivorous wildlife: New York State Department of Environmental Conservation Technical Report 87–3, 182 p.

Powell, J.R., 2003, Response of fish communities to cropland density and natural environmental setting in the 

Eastern Highland Rim ecoregion of the lower Tennessee 

River Basin, Alabama and Tennessee, 1999: U.S. Geological Survey Water-Resources Investigations Report 

02–4268 p 48.

Rabalais, N.N., 1996, Nutrient changes in the Mississippi 

River and system responses on the adjacent continental 

shelf: Estuaries, v. 19, p. 386–407.

Smith, R.W., and Whitlatch, G.I., 1940, The phosphate 

resources of Tennessee: Tennessee Division of Geology 

Bulletin 48, 444 p.

Squillace, P.J., Moran, M.J., Lapham, W.W., Price, C.V., 

Clawges, R.M., and Zogorski, J.S., 1999, Volatile organic 

compounds in untreated ambient groundwater of the United 

States, 1985–1995: Environmental Science & Technology, 

v. 33, no. 23, p. 4176–4187.
References Cited 25

Tennessee Department of Environment and Conservation, 

2002, The draft 2002 303(d) list: Division of Water Pollution Control, accessed September 30, 2002, at URL 

http://www.state.tn.us/environment/wpc/publications/

2002303dpropfinal.pdf

Tennessee Valley Authority, 2003, Preserving wildlife habitat: 

Tennessee Valley Authority, accessed March 10, 2003, at 

URL http://www.tva.gov/environment/land/habitat.htm

U.S. Census Bureau, 2003, Your gateway to census 2000: 

United States Census 2000, accessed March 24, 2003, at 

URL http://www.census.gov/main/www/cen2000.html

U.S. Environmental Protection Agency, 1986a, Ambient water 

quality criteria for bacteria, 1986: Cincinnati, Ohio, U.S. 

Environmental Protection Agency, EPA 440/5–84–002, 

18 p.

———1986b, Quality criteria for water 1986: Washington, 

D.C., Office of Water, U.S. Environmental Protection 

Agency, EPA 440/5–86–001.

——— 2002a, 2002 Edition of the drinking water standards 

and health advisories: Washington D.C., U.S. Environmental Protection Agency, accessed January 30, 2003, at URL 

http://www.epa.gov/ost/drinking/standards/dwstandards.pdf

——— 2002b, National Water Quality Inventory 2000 Report: 

Washington, D.C., Office of Water, U.S. Environmental Protection Agency, EPA841–R—02–001, 207 p.

U.S. Food and Drug Administration, 2002, Compliance policy 

guides: Office of Regulatory Affairs: Compliance, science, 

protection, accessed December 13, 2002, at URL http://

www.fda.gov/ora/compliance_ref/cpg/cpgfod/cpg575-100.

html

———2003, Center for Devices and Radiological Health: 

U.S. Food and Drug Adiminstration, accessed January 27, 

2003, at URL http://www.accessdata.fda.gov/scripts/cdrh/

cfdocs/cfcfr/CFRSearch.cfm?FR=109.30

Woodside, M.D., and Hoos, A.B., 2001, Nutrients in 

streams and rivers in the lower Tennessee River Basin: 

U.S. Geological Survey Fact Sheet FS–025–01, 6 p.
26 Water Quality in the Lower Tennessee River Basin

Glossary

Aquatic-life criteria - Water-quality guidelines for protection 

of aquatic life. Often refers to U.S. Environmental Protection 

Agency water-quality criteria for protection of aquatic organisms. 

Aquifer - A water-bearing layer of soil, sand, gravel, or rock 

that will yield usable quantities of water to a well. 

Base flow - Sustained, low flow in a stream; ground-water 

discharge is the source of base flow in most places. 

Bioaccumulation - The net accumulation of a substance by an 

organism as a result of uptake from all environmental sources, 

including gills, epithelial tissues, and dietary sources.

Carbonate rocks - Rocks (such as limestone or dolostone) 

that are composed primarily of minerals (such as calcite and 

dolomite) containing the carbonate ion (CO3

2-). 

Community - In ecology, the species that interact in a common 

area. 

Cubic foot per second (ft3/s, or cfs) - Rate of water discharge 

representing a volume of 1 cubic foot passing a given point 

during 1 second, equivalent to approximately 7.48 gallons per 

second or 448.8 gallons per minute or 0.02832 cubic meter per 

second. 

Degradation products - Compounds resulting from transformation of an organic substance through chemical, photochemical, and/or biochemical reactions. 

DDT - Dichloro-diphenyl-trichloroethane. An organochlorine 

insecticide no longer registered for use in the United States. 

Drinking-water standard or guideline - A threshold concentration in a public drinking-water supply, designed to protect 

human health. As defined here, standards are U.S. Environmental Protection Agency regulations that specify the maximum contamination levels for public water systems required 

to protect the public welfare; guidelines have no regulatory 

status and are issued in an advisory capacity. 

Ecoregion - An area of similar climate, landform, soil, 

potential natural vegetation, hydrology, or other ecologically 

relevant variables. 

Escherichia coli (E. coli) - Bacteria present in the intestine and 

feces of warm-blooded animals. E. coli are a member species 

of the fecal coliform group of indicator bacteria.

Eutrophication - The process by which water becomes 

enriched with plant nutrients, most commonly phosphorus and 

nitrogen. 

Flow-weighted mean - A concentration calculated by first 

multiplying each sample concentration by its associated 

streamflow value, then dividing the sum of these products 

by the sum of the streamflows. The resultant mean value 

accounts for the effects of variable streamflow on concentrations.

Hypoxia - Low dissolved oxygen concentrations, usually less 

than 2 parts per million, in lakes, estuaries, and coastal waters. 

In many cases, hypoxic waters do not have enough oxygen to 

support fish and other aquatic animals. Hypoxia can be caused 

by an excess of nutrients.

Karst - A type of topography that results from dissolution and 

collapse of carbonate rocks such as limestone and dolomite, 

and characterized by closed depressions or sinkholes, caves, 

and underground drainage. 

Load - General term that refers to a material or constituent in 

solution, in suspension, or in transport; usually expressed in 

terms of mass or volume. 

Main stem - The principal course of a river or a stream. 

Maximum contaminant level (MCL) - Maximum permissible 

level of a contaminant in water that is delivered to any user of 

a public water system. MCLs are enforceable standards established by the U.S. Environmental Protection Agency. 

Micrograms per liter (μg/L) - A unit expressing the concentration of constituents in solution as weight (micrograms) of solute per unit volume (liter) of water; equivalent to one part per 

billion in most streamwater and ground water. One thousand 

micrograms per liter equals 1 milligram per liter. 

Milligrams per liter (mg/L) - A unit expressing the concentration of chemical constituents in solution as weight (milligrams) of solute per unit volume (liter) of water; equivalent 

to one part per million in most streamwater and ground water. 

One thousand micrograms per liter equals 1 milligram per 

liter. 

Monitoring well - A well designed for measuring water levels 

and testing ground-water quality. 

Nitrate - An ion consisting of nitrogen and oxygen (NO3

-

). 

Nitrate is a plant nutrient and is very mobile in soils. 

Nonpoint-source water pollution - Water contamination that 

originates from a broad area (such as leaching of agricultural 

chemicals from crop land) and enters the water resource diffusely over a large area. 

Nutrient - Element or compound essential for animal and plant 

growth. Common nutrients in fertilizer include nitrogen, phosphorus, and potassium. 

Phosphorus - A nutrient essential for growth that can play a 

key role in stimulating aquatic growth in lakes and streams. 

Point source - A source at a discrete location such as a 

discharge pipe, drainage ditch, tunnel, well, concentrated livestock operation, or floating craft. 

Polychlorinated biphenyls (PCBs) - A mixture of chlorinated 

derivatives of biphenyl, marketed under the trade name Aroclor with a number designating the chlorine content (such as 

Aroclor 1260). PCBs were used in transformers and capacitors 
Glossary 27

for insulating purposes and in gas pipeline systems as a lubri-

cant. Further sale for new use was banned by law in 1979. 

Turbidity - Reduced clarity of surface water because of sus-

pended particles, usually sediment. 

Volatile organic compounds (VOCs) - Organic chemicals 

that have a high vapor pressure relative to their water solu-

bility. VOCs include components of gasoline, fuel oils, and 

lubricants, as well as organic solvents, fumigants, some inert 

ingredients in pesticides, and some byproducts of chlorine 

disinfection. 

Water-quality standards - State-adopted and U.S. Environ-

mental Protection Agency-approved ambient standards for 

water bodies. Standards include the use of the water body and 

the water-quality criteria that must be met to protect the desig-

nated use or uses. 

Water year - The continuous 12-month period, October 1 

through September 30, in U.S. Geological Survey reports deal-

ing with the surface-water supply. The water year is desig-

nated by the calendar year in which it ends and which includes 

9 of the 12 months. Thus, the year ending September 30, 1980, 

is referred to as water year 1980. 
28 Water Quality in The Lower Tennessee River Basin

Appendix—Water Quality Data from the Lower Tennessee River 

Basin in a National Context

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Coordination with agencies and organizations in the Lower Tennessee River Basin was integral 

to the success of this water-quality assessment. We thank those who served as members of our 

liaison committee. 

Federal Agencies

Tennessee Valley Authority

Natural Resources Conservation Service

U.S. Fish and Wildlife Service

State Agencies

Alabama Department of Environmental 

Management

Alabama Department of Conservation 

and Natural Resources

Geological Survey of Alabama

Tennessee Department of Environment 

and Conservation

Tennessee Wildlife Resources Agency

Tennessee Department of Agriculture

Local Agencies

Huntsville Utilities

Madison County Water Department

Sand-Mountain-Lake Guntersville 

 Conservancy District

Universities

University of Alabama

Auburn University

Other public and private organizations

The Nature Conservancy

Duck River Development Agency

Flint River Conservation Association

We thank the following individuals, agencies, and organizations for contributing to this study. 

• Susan Weber (Flint River Conservation Association) for providing watershed information and coordinating stream 

access with landowners.

• Charles Saylor and Amy Wales (Tennessee Valley Authority) for assisting with fish identification and electroshocking.

• Dr. David Etnier (University of Tennessee) and Dr. Richard Mayden (University of Alabama) for verifying and archiving 

fish specimens.

• John Shelton and Wade Bryant (USGS) for assistance with study design, data collection, and data interpretation.

• Elisabeth Scribner (USGS) for analyzing selected pesticides.

• Pixie Hamilton, Gerard McMahon, and Peter Ruhl (USGS), Lynn Sisk (Alabama Department of Environmental Management) for providing technical reviews of the report, and Rebecca Deckard, Martha Erwin, and Sandra Cooper (USGS) for 

editorial input.

• The landowners who allowed the USGS to access streams, install monitoring wells, or sample existing domestic and 

public-supply wells. 
Woodside and others— Water Quality in the Lower Tennessee River Basin 

U.S. Geological Survey Circular 1233

National Water-Quality Assessment (NAWQA) Program

Lower Tennessee River Basin

NAWQA

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