Environmental Setting and Water-Quality Issues 

in the Lower Tennessee River Basin

By JAMES A. KINGSBURY, ANNE B. HOOS, and MICHAEL D. WOODSIDE 

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 99-4080

Nashville, Tennessee

1999
U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Any use of trade, product, or firm name in this report is for identification

purposes only and does not constitute endorsement by the

U.S. Geological Survey.

For additional information write to: Copies of this report may be purchased from:

District Chief U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

640 Grassmere Park, Suite 100 Box 25286

Nashville, Tennessee 37211 Denver, Colorado 80225-0286
FOREWORD

The mission of the U.S. Geological Survey 

(USGS) is to assess the quantity and quality of the 

earth resources of the Nation and to provide information that will assist resource managers and policymakers at Federal, State, and local levels in making sound 

decisions. Assessment of water-quality conditions and 

trends is an important part of this overall mission.

One of the greatest challenges faced by waterresources scientists is acquiring reliable information 

that will guide the use and protection of the Nation’s 

water resources. That challenge is being addressed by 

Federal, State, interstate, and local water-resource 

agencies and by many academic institutions. These 

organizations are collecting water-quality data for a 

host of purposes that include: compliance with permits 

and water-supply standards; development of remediation plans for specific contamination problems; operational decisions on industrial, wastewater, or watersupply facilities; and research on factors that affect 

water quality. An additional need for water-quality 

information is to provide a basis on which regionaland national-level policy decisions can be based. Wise 

decisions must be based on sound information. As a 

society we need to know whether certain types of 

water-quality problems are isolated or ubiquitous, 

whether there are significant differences in conditions 

among regions, whether the conditions are changing 

over time, and why these conditions change from place 

to place and over time. The information can be used to 

help determine the efficacy of existing water-quality 

policies and to help analysts determine the need for 

and likely consequences of new policies.

To address these needs, the U.S. Congress appropriated funds in 1986 for the USGS to begin a pilot program in seven project areas to develop and refine the 

National Water-Quality Assessment (NAWQA) Program. In 1991, the USGS began full implementation of 

the program. The NAWQA Program builds upon an 

existing base of water-quality studies of the USGS, as 

well as those of other Federal, State, and local agencies. 

The objectives of the NAWQA Program are to:

• Describe current water-quality conditions for a 

large part of the Nation’s freshwater streams, 

rivers, and aquifers.

• Describe how water quality is changing over 

time.

• Improve understanding of the primary natural 

and human factors that affect water-quality

conditions.

This information will help support the development 

and evaluation of management, regulatory, and monitoring decisions by other Federal, State, and local 

agencies to protect, use, and enhance water resources. 

The goals of the NAWQA Program are being 

achieved through ongoing and proposed investigations 

of 60 of the Nation’s most important river basins and 

aquifer systems, which are referred to as study units. 

These study units are distributed throughout the 

Nation and cover a diversity of hydrogeologic settings. 

More than two-thirds of the Nation’s freshwater use 

occurs within the 60 study units and more than twothirds of the people served by public water-supply systems live within their boundaries.

National synthesis of data analysis, based on 

aggregation of comparable information obtained from 

the study units, is a major component of the program. 

This effort focuses on selected water-quality topics 

using nationally consistent information. Comparative 

studies will explain differences and similarities in 

observed water-quality conditions among study areas 

and will identify changes and trends and their causes. 

The first topics addressed by the national synthesis are 

pesticides, nutrients, volatile organic compounds, and 

aquatic biology. Discussions on these and other waterquality topics will be published in periodic summaries 

of the quality of the Nation’s ground and surface water 

as the information becomes available.

This report is an element of the comprehensive 

body of information developed as part of the NAWQA 

Program. The program depends heavily on the advice, 

cooperation, and information from many Federal, 

State, interstate, Tribal, and local agencies and the 

public. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch

Chief Hydrologist

Contents v

CONTENTS

Abstract.................................................................................................................................................................................. 1

Introduction ........................................................................................................................................................................... 2

Purpose and Scope....................................................................................................................................................... 2

Acknowledgments ....................................................................................................................................................... 2

Environmental Setting ........................................................................................................................................................... 2

Natural Setting............................................................................................................................................................. 5

Geology and Soils.............................................................................................................................................. 5

Physiography and Ecoregions ........................................................................................................................... 9

Climate .............................................................................................................................................................. 9

Surface Water..................................................................................................................................................... 10

Ground Water..................................................................................................................................................... 14

Surface- and Ground-Water Interactions ........................................................................................................... 14

Cultural Setting ........................................................................................................................................................... 17

Reservoirs ......................................................................................................................................................... 19

Water Use .......................................................................................................................................................... 20

Wastewater Discharge........................................................................................................................................ 23

Population, Land Use, and Land Cover ............................................................................................................ 24

Nonpoint-Source Nutrient Inputs ..................................................................................................................... 29

Pesticide Use...................................................................................................................................................... 31

Water-Quality Issues ............................................................................................................................................................. 32

Selected Water-Quality Data ...................................................................................................................................... 33

Nutrients in Surface and Ground Water............................................................................................................. 33

Bacteria in Surface and Ground Water .............................................................................................................. 40

Summary................................................................................................................................................................................ 41

References ............................................................................................................................................................................ 43
vi Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

FIGURES

1–7. Maps showing:

1. Location of the lower Tennessee River Basin study unit, physiographic provinces 

in the study unit, and NAWQA study units nationwide ................................................................................... 3

2. Location of subunits of the lower Tennessee River Basin................................................................................ 4

3. Generalized geology of the lower Tennessee River Basin .............................................................................. 6

4. Location of phosphatic limestones in the lower Tennessee River Basin.......................................................... 7

5. Soil hydrologic groups in the lower Tennessee River Basin ........................................................................... 8

6. Level III ecoregions in the lower Tennessee River Basin ................................................................................ 10

7. Distribution of average annual precipitation in the lower Tennessee River Basin, 1961-90 ........................... 11

8-10. Graphs showing:

8. Average monthly precipitation at Athens, Alabama, in the 

lower Tennessee River Basin, 1961-90 ............................................................................................................ 11

9. Long-term mean-annual streamflow for selected streams in the lower Tennessee River Basin ..................... 12

10. Mean-daily discharge for the Tennessee River at Savannah, Tennessee, and 

the Duck River above Hurricane Mills, Tennessee, water year 1992............................................................... 13

11. Chart showing principal aquifers in the lower Tennessee River Basin .................................................................... 15

12. Diagrams showing conceptual models of ground-water occurrence in bedrock aquifers 

in the lower Tennessee River Basin.......................................................................................................................... 16

13. Map showing major drainages and mean-annual surface-water runoff, 1951-80, in the lower 

Tennessee River Basin.............................................................................................................................................. 19

14. Graph showing estimated water use by withdrawal type in the lower Tennessee River Basin, 1995...................... 20

15. Map and graph showing location and size of public-supply surface-water withdrawals and summary 

of withdrawals by subunit and water body in the lower Tennessee River Basin, 1995............................................ 21

16. Map and graph showing location and size of public-supply ground-water withdrawals and distribution 

of public-supply and domestic withdrawals by subunit in the lower Tennessee River Basin, 1995 ........................ 22

17-19. Maps showing:

17. Location of wastewater dischargers, and relative size of discharge, in the lower 

Tennessee River Basin, 1995 ........................................................................................................................... 23

18. Population in the lower Tennessee River Basin, by county, 1995.................................................................... 25

19. Land use in the lower Tennessee River Basin, 1992 ........................................................................................ 27

20-22. Graphs showing:

20. Distribution of predominant crops by subunit in the lower Tennessee River Basin, 1992............................... 28

21. Distribution of predominant livestock by subunit in the lower Tennessee River Basin, 1992 ......................... 29

22. Estimated unit area total nitrogen and phosphorus inputs from nonpoint sources 

by subunit in the lower Tennessee River Basin, 1992 ...................................................................................... 31

23. Map showing location of surface-water-quality sites and ground-water-quality sites that have

data for nutrients in STORET or WATSTORE, 1980-96 ......................................................................................... 36

24. Graphs showing concentrations of selected nutrients in surface and ground water by subunit 

in the lower Tennessee River Basin, 1980-96 .......................................................................................................... 39

25. Graphs showing counts of fecal coliform in surface and ground water by subunit

in the lower Tennessee River Basin, 1980-96 .................................................................................... ...................... 40

TABLES

1. Streamflow and baseflow estimates for selected streams in the lower Tennessee River Basin ............................... 18

2. Summary of land use and population by subunit in the lower Tennessee River Basin, 1992.................................. 26

3. Estimated crop production and livestock population by subunit in the lower 

Tennessee River Basin, 1992 ................................................................................................................................... 28

4. Estimated total nitrogen and phosphorus inputs from nonpoint sources by

subunit in the lower Tennessee River Basin, 1992 ................................................................................................... 30

5. Estimated use of selected pesticides by subunit in the lower Tennessee River Basin, 1992 ................................... 34
Contents vii

CONVERSION FACTORS AND VERTICAL DATUM

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C = (°F - 32) / 1.8

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929—a geodetic datum derived from a general adjustment of the first-order level nets of the United States and

Canada, formerly called Sea Level Datum of 1929.

Altitude, as used in this report, refers to distance above or below sea level.

Multiply By To obtain

inch (in.) 2.54 centimeter

inch per year (in/yr) 2.54 centimeter per year

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

acre 0.004047 square kilometer

square mile (mi2) 2.590 square kilometer 

pound (lb) 0.4536 kilogram 

ton 0.9072 metric ton 

pound per square mile (lb/mi2

) 1.1748 kilogram per square kilometer

acre-foot (acre-ft) 1,233 cubic meter

cubic foot per second (ft3/s) 0.02832 cubic meter per second 

cubic foot per second per square mile [(ft3

/s)/mi2] 0.01093 cubic meter per second per square kilometer

gallon per minute (gal/min) 0.06309 liter per second

million gallons per day (Mgal/d) 0.04381 cubic meter per second

foot per mile (ft/mi) 0.1894 meter per kilometer
viii Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Abstract 1

Environmental Setting and Water-Quality Issues

in the Lower Tennessee River Basin

By James A. Kingsbury, Anne B. Hoos, and Michael D. Woodside

Abstract

The goals of the National Water-Quality 

Assessment Program are to describe current 

water-quality conditions for a large part of the 

Nation’s water resources, identify water-quality 

changes over time, and identify the primary natural and human factors that affect water quality. 

The lower Tennessee River Basin is one of 59 

river basins selected for study. The water-quality 

assessment of the lower Tennessee River Basin 

study unit began in 1997. The lower Tennessee 

River Basin study unit encompasses an area of 

about 19,500 square miles and extends from Chattanooga, Tennessee, to Paducah, Kentucky. The 

study unit had a population of about 1.5 million 

people in 1995.

The study unit was subdivided into subunits 

with relatively homogeneous geology and physiography. Subdivision of the study unit creates a 

framework to assess the effects of natural and cultural settings on water quality. Nine subunits were 

delineated in the study unit; their boundaries generally coincide with level III and level IV ecoregion boundaries. The nine subunits are the 

Coastal Plain, Transition, Western Highland Rim, 

Outer Nashville Basin, Inner Nashville Basin, 

Eastern Highland Rim, Plateau Escarpment and 

Valleys, Cumberland Plateau, and Valley and 

Ridge.

The lower Tennessee River Basin consists 

of predominantly forest (51 percent) and agricultural land (40 percent). Activities related to agricultural land use, therefore, are the primary 

cultural factors likely to have a widespread effect 

on surface- and ground-water quality in the study 

unit. Inputs of total nitrogen and phosphorus from 

agricultural activities in 1992 were about 161,000 

and 37,900 tons, respectively. About 3.7 million 

pounds (active ingredient) of pesticides was 

applied to crops in the lower Tennessee River 

Basin in 1992.

State water-quality agencies identified 

nutrient enrichment and pathogens as waterquality issues affecting both surface and ground 

water in the lower Tennessee River Basin. Waterquality data collected by State and Federal agencies between 1980 and 1996 were summarized to 

characterize surface- and ground-water quality of 

the subunits with respect to these issues. Median 

concentrations of nitrogen species generally were 

less than 1 milligram per liter in surface and 

ground water in all subunits, and were highest 

throughout the subunits that had the largest percentages of agricultural land use. Median phosphorus concentrations also were less than 

1 milligram per liter in all subunits. Phosphatic 

limestones present in two subunits had a larger 

effect on phosphorus concentrations in surface 

and ground water than did the amount of agricultural land use in these subunits. Median counts of 

fecal coliform were higher in surface water than 

in ground water in all subunits. The highest 

median counts in surface water were in the Valley 

and Ridge (7,500 colonies per 100 milliliters) and 

the Outer Nashville Basin subunits (5,000 colonies per 100 milliliters). Highest median counts in 

ground water were in the Inner and Outer Nashville Basin subunit. Natural setting likely has an 

important effect with respect to fecal contamination of surface and ground water in the lower 

Tennessee River Basin.
2 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

INTRODUCTION

The U.S. Geological Survey (USGS) began full 

scale implementation of the National Water-Quality 

Assessment (NAWQA) Program in 1991. The goals of 

the NAWQA Program are (1) to describe current 

water-quality conditions for a large number of the 

Nation’s freshwater streams and aquifers; (2) to 

describe how water quality is changing over time; and 

(3) to improve understanding of the primary natural 

and human factors that affect water quality. To achieve 

these goals, water-quality investigations of 59 river 

basins and aquifer systems have been conducted or are 

currently ongoing (fig. 1). About 70 percent of the 

Nation’s freshwater use is within these basins. The 

basins, referred to as study units, were selected to represent the diverse geography, water resources, and land 

and water use of the Nation. The lower Tennessee 

River Basin is one of the 59 river basins selected for a 

water-quality assessment.

The lower Tennessee River Basin NAWQA 

study unit extends from Chattanooga, Tennessee, to 

near Paducah, Kentucky (fig. 1), and encompasses 

about 19,500 square miles (mi2

). Most of the study 

unit is in Middle Tennessee and northern Alabama, 

with smaller parts in southwestern Kentucky, northeastern Mississippi, and northwestern Georgia (fig. 1). 

Parts of the Coastal Plain, Interior Lowland Plateaus, 

and Appalachian Plateaus Physiographic Provinces are 

in the study unit (fig. 1). The main stem of the Tennessee River is highly regulated with few free-flowing 

stream reaches. Six large reservoirs are located on the 

main stem (fig. 1), and many additional reservoirs are 

located on tributaries to the main stem.

Project activities for the water-quality assessment of the lower Tennessee River Basin began in 

1997. Initial activities for the study included characterizing the environmental setting of the study unit, subdividing the study unit into subunits with relatively 

homogeneous geology and physiography, and inventorying and analyzing historical water-quality data. The 

historical data analysis helped to identify water-quality 

issues in the study unit and to determine the spatial 

distribution of existing water-quality data.

Purpose and Scope

The purpose of this report is to describe the 

environmental setting and water-quality issues of the 

lower Tennessee River Basin. The environmental 

setting includes the natural and cultural factors that 

affect water quality. Natural factors in the lower Tennessee River Basin include geology, physiography, 

soils, climate, and surface- and ground-water hydrology. Geology and physiography are the primary natural factors that were used to subdivide the study unit 

into nine subunits within which the effects of anthropogenic (cultural) factors on water quality can be evaluated. Cultural factors described in this report include 

wastewater discharge, water use, and land use. Land 

use can be used as a surrogate for the distribution of 

nonpoint-source inputs that affect water quality. This 

report also presents data for the distribution of major 

crops, livestock, and agricultural-chemical use for 

1992. Historical water-quality data for two constituents (nutrients and bacteria) that are water-quality 

issues in the study unit are summarized.

Acknowledgments

The authors thank the following individuals for 

their thoughtful input and suggestions in the delineation of the subunits in the lower Tennessee River 

Basin—Danny Moore, Geological Survey of Alabama, for providing a technical review of the subunit 

boundaries; Glendon Smalley, formerly of the U.S. 

Forest Service, for providing guidance on the delineation of the Highland Rim subunits; John Jenkins, Natural Resources Conservation Service, Tennessee, for 

providing insight on the surficial deposits and soils; 

Jim Omernik, U.S. Environmental Protection Agency, 

and Glenn Griffith, Natural Resources Conservation 

Service, for their contribution to the conceptualization 

of the subunits through their work on delineating 

level IV ecoregions in Tennessee, and Glenn Griffith 

for providing a digital version of the level IV ecoregion boundaries; as well as Bob Kidd, Pat Hollyday, 

and Bill Wolfe of the U.S. Geological Survey for providing insight on the hydrogeologic and geomorphologic aspects of the subunits. We also thank Enid 

Bittner, Alabama Department of Environmental Management, Sydney DeJarnette, Geological Survey of 

Alabama, and Ken Nafe and Tim Thompson, Tennessee Department of Agriculture who provided waterquality data from ground-water studies.

ENVIRONMENTAL SETTING

Environmental setting described in this report 

includes aspects of both natural and cultural settings of 
Environmental Setting 3

KENTUCKY

88

87

86

o

o

o

36o

35o

Duck

River

Elk

River

Clar ks

R

iver

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock

Ri v er

Beech River

Sequatchie River

Paducah

River

Kentucky

Lake

Wheeler

Lake Wilson Lake

Pickwick

L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big

Sandy River

TENNESSEE

GEORGIA

Chattanooga

Columbia

TENNESSEE

ALABAMA

MISSISSIPPI

Huntsville

Decatur

Florence

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

Figure 1. (A) Location of the Lower Tennessee River Basin study unit, (B) Physiographic Provinces

in the study unit, and (C) NAWQA study units nationwide.

NAWQA study units

Town

Creek

Base from U.S. Geological Survey,

Study unit

Georgia Mississippi Alabama

Kentucky

Tennessee

COASTAL PLAIN

INTERIOR LOW PLATEAUS

APPALACHIAN

PLATEAUS

Physiographic provinces

Lower Tennessee River

Basin study unit

A

B

C

Figure 1. (A) Location of the lower Tennessee River Basin study unit, (B) physiographic provinces in the study unit, and 

(C) NAWQA study units nationwide.
4 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph Modified from King and Beikman, 1974; Smalley, 1983;

Osborne and others, 1989; and Griffith and others, 1997

Base from U.S. Geological Survey,

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

Figure 2. Location of subunits of the lower Tennessee River Basin.

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

the lower Tennessee River Basin and their effects on 

water quality. Natural setting affects the distribution of 

physical properties, such as temperature, dissolved 

oxygen, and pH, and the occurrence and distribution of 

major and some trace inorganic constituents of surface 

and ground water. Cultural setting influences the quality of water that results from natural processes. Modification of the hydrologic system and other activities, 

such as dam construction, cultivation of land, and mining, increase the mobility of naturally occurring waterquality constituents and affect water quality. Human 

activities also introduce naturally occurring compounds where they are not normally present, or in 

amounts greater than would be present naturally (fertilizer use), and introduce compounds that do not 

occur naturally anywhere in the environment (synthetic organic compounds such as pesticides). In order 

to assess the effect of human-related activities on 

water quality, an estimate of the natural variability in 

water quality is needed.

Geology and physiography were the primary 

natural factors used to subdivide the lower Tennessee 

River Basin into nine subunits that represent areas of 

relative lithologic, and physical or geomorphic homogeneity (fig. 2). Subdivision of the study unit based on 

these natural factors provides a framework in which 

natural variability in water quality can be quantified 

and the effects of cultural factors on water quality can 

be assessed. This framework is similar to the ecoregion framework used by State and Federal agencies for 

Figure 2. Location of subunits of the lower Tennessee River Basin.
Environmental Setting 5

evaluating and managing environmental and water 

resources (Bailey and others, 1994). Level III ecoregion boundaries were used to define the boundaries for 

the subunits and level IV ecoregion boundaries were 

used in Tennessee (Griffith and others, 1997). Geologic contacts were used instead of level IV ecoregion 

boundaries to define subunit boundaries in northern 

Alabama, Georgia, and Mississippi, because level IV 

ecoregion boundary delineations were unavailable in 

these areas. However, this substitution for the boundaries does not affect regional consistency of the delineation, because the boundaries for the level IV 

ecoregions in the lower Tennessee River Basin generally correspond to the boundaries of geologic units.

Subunits delineated in the lower Tennessee 

River Basin are the Coastal Plain, Transition, Western 

Highland Rim, Outer Nashville Basin, Inner Nashville 

Basin, Eastern Highland Rim, Plateau Escarpment and 

Valleys, Cumberland Plateau, and Valley and Ridge 

(fig. 2). The natural and cultural settings within these 

subunits is described in the following sections.

Natural Setting

Geology and soils are the primary factors of the 

natural setting that affect the chemical composition of 

ground and surface water. The effect of the water-rock 

interaction on water quality or the amount of solids 

that dissolve from the rock is dependent on rock type 

and length of time water is in contact with rock. Soil 

properties, climate, and ground- and surface-water 

hydrology affect the movement of water in a watershed, and therefore affect the water-rock interaction.

Geology and Soils

Carbonate rocks underlie much of the lower 

Tennessee River Basin, but unconsolidated sediments 

and siliciclastic rocks crop out in the extreme western 

part and in the eastern parts and extreme southern parts 

of the study unit, respectively (fig. 3). Ordovician-age 

carbonates generally crop out near the center of the 

study unit (fig. 3), and are predominantly limestone 

with some thin shaly beds and bentonite layers. Phosphatic limestones are present in three Ordovician-age 

formations: the Hermitage Formation, the Bigby 

Limestone, and the Leipers Formation. Phosphate has 

been mined commercially in the Bigby Limestone and 

the Leipers Formation in the Nashville Basin (Miller, 

1974). Ordovician phosphatic limestones and residuum in the study unit generally crop out in a northsouth trending band in Maury and Giles Counties, 

Tennessee, and Limestone County, Alabama (fig. 4). 

Most of the Ordovician-age rocks crop out in an 

area that is a topographic basin (fig. 3), but was originally a structural dome (Nashville Dome). Uplift and 

fracturing of this area during the late Paleozoic Era 

accelerated erosion of the younger, more resistant 

rocks overlying the Ordovician carbonates, and 

resulted in subsequent erosion of the Ordovician carbonates creating a topographic basin (fig. 3). The 

Ordovician carbonates are undeformed and relatively 

flat-lying to gently dipping; however, stresses related 

to doming formed joints in most of the area. A thin 

outcrop of Ordovician carbonate is present in the 

Sequatchie Valley, an eroded anticlinal valley (fig. 3), 

and minor outcrops are present in the extreme eastern 

part of the study unit. The Sequatchie Valley represents the western extent of deformation and folding 

associated with the Appalachian Mountains. The 

Ordovician carbonates are characterized by karst landforms, such as sinkholes, caves, and disappearing 

streams. These rocks are the predominant geologic 

units in the Outer and Inner Nashville Basin.

Devonian- and Silurian-age rocks crop out in a 

limited area in the western part of the study unit 

(fig. 3) and are predominantly carbonates. Phosphatic 

limestones and phosphatic residuum also are present 

in areas underlain by Devonian- and Silurian-age 

rocks (fig. 4); however, these deposits are generally 

scattered and isolated (Smith and Whitlatch, 1940). 

These rocks are relatively flat-lying to gently dipping 

away from the Nashville Dome. The Chattanooga 

Shale is the uppermost unit of the Devonian-age rocks 

(fig. 3). These rocks crop out primarily in the Western 

Highland Rim, with minor outcrops also in the Transition and Coastal Plain.

Mississippian-age carbonate rocks are the most 

areally extensive geologic unit in the study unit 

(fig. 3). The Mississippian-age carbonates are predominantly limestone, but some shaly beds and chert interbeds and nodules also are present. The amount of 

insoluble material (clay and chert) in the Mississippianage carbonates is greater than that in the Ordovicianage carbonates, resulting in the development of a 

thicker regolith or residuum above bedrock than is 

present above the Ordovician-age carbonates. The 

Mississippian-age carbonates are relatively flat-lying 

to gently dipping away from the Nashville Dome, 

except in the areas near the Sequatchie Valley where 

folding has occurred. Parts of the study unit underlain 
6 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35o

Base derived from U.S. Geological Survey,

1:2,000,000 digital line graph

EXPLANATION

ROCK UNITS

TERTIARY SAND, SILT, AND CLAY

CRETACEOUS SAND, SILT, AND

 CLAY

PENNSYLVANIAN SANDSTONES

LINE OF GEOLOGIC SECTION

MISSISSIPPIAN CARBONATES

DEVONIAN-SILURIAN

 CARBONATES

ORDOVICIAN CARBONATES

Figure 3. Generalized geology of the lower Tennessee River Basin.

Modified from King and Beikman, 1974

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

A

A'

A A'

Fault

Chattanooga Shale

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

1,800

1,200

600

Sea Level

FEET

TENNESSEE

RIVER

NASHVILLE

DOME

SEQUATCHIE

VALLEY

VERTICAL SCALE GREATLY EXAGGERATED

A A'

Figure 3. Generalized geology of the lower Tennessee River Basin.
Environmental Setting 7

86

87

88

36

35

o

o

o

o

o

EXPLANATION

MOORE

COFFEE

GRUNDY

MARION

SEQUATCHIE

BLEDSOE

CUMBERLAND

VAN BUREN

HAMILTON

FRANKLIN

JACKSON MADISON

DEKALB

DADE

WALKER

MARSHALL

MORGAN

CULLMAN

BLOUNT

ETOWAH

LINCOLN

LIMESTONE

LAWRENCE

FRANKLIN

COLBERT

LAUDERDALE

TISHOMINGO

ALCORN

PRENTISS

BEDFORD

MARSHALL

GILES WAYNE LAWRENCE HARDIN

MCNAIRY

CHESTER

HENDERSON

DECATUR

PERRY

LEWIS MAURY

WILLIAMSON

RUTHERFORD

HICKMAN

HUMPHREYS

DICKSON

HOUSTON

HENRY

CARROLL

BENTON

STEWART

CALLOWAY

MARSHALL

GRAVES

MCCRACKEN

LIVINGSTON

LYON

TRIGG

MARION

WINSTON

1:2,000,000 digital line graph

Base from U.S. Geological Survey,

Huntsville Decatur

Florence

Chattanooga

Paducah

Columbia

PREDOMINANTLY

ORDOVICIAN

ROCKS

Figure 4. Location of phosphatic limestones in the lower Tennessee River Basin.

PREDOMINANTLY

 DEVONIAN- AND

 SILURIAN-AGE

 ROCKS

Modified from Smith and Whitlatch, 1940;

and McMaster, 1965 a and b

Figure 4. Location of phosphatic limestones in the lower Tennessee River Basin.

by Mississippian-age carbonates are characterized by 

karst landforms. The Eastern and Western Highland 

Rim are underlain by these rocks, and these rocks outcrop in the valleys of the Plateau Escarpment and Valleys and Transition.

Pennsylvanian-age rocks located in the eastern 

and southern part of the study unit (fig. 3) generally 

are siliciclastic with some coal beds present. These 

rocks are characterized by repeating sequences of 

sandstone, shale, and coal. The rocks dip gently [20 to 

50 feet per mile (ft/mi)] to the east (Brahana and others, 1986a). Generally, the Pennsylvanian-age rocks 

are undeformed, but fractures are present in many 

parts of these geologic units. These rocks are the predominant lithology in the Cumberland Plateau and 

also cap the hills in the Plateau Escarpment and Valleys.

Unconsolidated sand, silt, and clay of predominantly Late Cretaceous to Tertiary age are located at 

the western edge of the study unit (fig. 3). These 

sediments dip to the west at a rate of about 35 ft/mi 

(Brahana and others, 1986b) and thicken in the direction of dip. Quaternary alluvial deposits and loess are 

present locally. These sediments are primarily in the 

Coastal Plain and the Transition.

Soils develop from physical and chemical 

weathering of the underlying rocks or sediments: 

sandy, well-drained soils tend to develop in areas 

where sand or sandstone are the predominant lithology 

and clayey, poorly drained soils develop in areas 

where clays, shale, or shaly limestone are present. 

Other factors that affect the development of soils are 

topographic relief, climate, and plant growth.

Soil type has implications for ground- and 

surface-water quality. Well-drained, coarse textured 

soils have a higher relative infiltration rate and transmit precipitation or recharge to aquifers more readily 

than poorly drained soils. A higher infiltration rate 

increases the probability of contamination of groundwater aquifers from surface sources. A slower infiltration rate increases the potential for precipitation to 
8 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Base derived from U.S. Geological Survey,

1:2,000,000 digital line graph

EXPLANATION

SOIL HYDROLOGIC GROUPS

of Agriculture, 1994

Figure 5. Soil hydrologic groups in the lower Tennessee River Basin.

Modified from U.S. Department

HIGH INFILTRATION

MODERATE INFILTRATION

SLOW INFILTRATION

VERY SLOW INFILTRATION

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

KENTUCKY

TENNESSEE

become surface runoff, and increases the probability of 

surface contaminant transport to surface-water bodies. 

About 60 percent of the area of the lower Tennessee River Basin is covered with soils with moderate infiltration rates. These soils overlie primarily the 

Ordovician- and Mississippian-age carbonate rocks 

and generally are in the Outer Nashville Basin, Western Highland Rim, and Transition subunits (fig. 5). 

Soils with slow infiltration rates cover about 

38 percent of the study unit. These soils primarily 

overlie the sandstone and unconsolidated sand, but 

also overlie carbonate rock in the Inner Nashville 

Basin, Plateau Escarpment and Valleys, and Cumberland Plateau. The Eastern Highland Rim and Coastal 

Plain have a mixture of soils with moderate to slow 

infiltration rates, and in some places very slow infiltration rates, which cover about 2 percent of the area. 

Soils with high infiltration rates are present in less 

Figure 5. Soil hydrologic groups in the lower Tennessee River Basin.
Environmental Setting 9

than 1 percent of the area and are located at the northern and eastern parts of the area in the Valley and 

Ridge and the Western Highland Rim. The remainder 

of the study unit is open water bodies.

Other properties of soil that have implications 

for water quality are the organic content of the soil, 

which affects the transport of pesticides and other 

organic compounds. Soil slope and erosion potential 

affects the movement of both soil and water-quality 

constituents associated with soil. The chemical 

composition of soil also affects water quality through 

processes such as cation exchange between water and 

soil.

Physiography and Ecoregions

The lower Tennessee River Basin includes parts 

of the Coastal Plain, Interior Low Plateaus, and Appalachian Plateaus Physiographic Provinces. The Coastal 

Plain Physiographic Province is located along the 

western edge of the study unit (fig. 1). It is an area of 

relatively low topographic relief with land-surface altitudes of about 650 ft above sea level. 

The Interior Low Plateaus Physiographic Province covers most of the study unit (fig. 1) and is subdivided into the Nashville Basin and Highland Rim 

Physiographic Sections (fig. 2). The Nashville Basin, 

locally also called the Central Basin, has low to moderate relief with some small hills and knobs. Local 

relief of more than 100 ft is common (Fenneman, 

1938). Land-surface altitudes generally are about 

700 ft above sea level. The Highland Rim surrounds 

the Nashville Basin and is underlain predominantly by 

Mississippian carbonate rocks. The boundary between 

these two physiographic sections is an escarpment 

with about 300 ft of relief. Southwest and west of the 

Nashville Basin the Highland Rim generally has more 

relief and is more dissected than to the south and east. 

Land-surface altitudes range from 500 ft near the Tennessee River to 900 ft elsewhere. East of the Nashville 

Basin, the Highland Rim is a relatively even plateau 

dissected by a few entrenched meandering streams. 

Land-surface altitudes reach 1,300 ft, but generally are 

about 1,000 ft above sea level. Total relief in the Highland Rim is about 650 ft. Karst features such as caves, 

sinkholes, and springs are present in the Nashville 

Basin and the Highland Rim. 

The Interior Low Plateaus are bounded to the 

south and east by the Cumberland Plateau Section of 

the Appalachian Plateaus Physiographic Province 

(figs. 1 and 2). A steep escarpment separates the Cumberland Plateau from the Highland Rim with the average altitude of the plateau about 1,000 ft above the 

Highland Rim. The Sequatchie Valley (fig. 3) lies 

about 500 ft lower than the adjacent upland parts of the 

Cumberland Plateau (Fenneman, 1938). East of the 

Sequatchie Valley is a plateau locally known as Walden 

Ridge or Sand Mountain, with an average land-surface 

altitude of about 1,300 ft and relief generally between 

100 and 200 ft. In contrast, west of the Sequatchie Valley, the Cumberland Plateau is more dissected with 

land-surface altitudes ranging from about 1,000 to 

1,600 ft with local relief as much as 300 ft.

Ecoregions represent areas in which factors 

(soils, vegetation, climate, geology, and physiography) 

affecting terrestrial and aquatic ecological systems are 

relatively uniform (Griffith and others, 1997). Ecoregion boundaries provide a framework for evaluating 

and managing environmental resources. Ninety-eight 

level III ecoregions have been defined across the 

nation (Bailey and others, 1994). The lower Tennessee 

River Basin includes parts of six level III ecoregions 

(fig. 6), which generally correspond to the physiographic provinces with some additional subdivision. 

Most of the study unit is in the Interior Plateau ecoregion, which corresponds to the Interior Low Plateaus 

Physiographic Province. The Southwestern Appalachians ecoregion corresponds to the Appalachian Plateaus Physiographic Province, and the Southeastern 

Plains is roughly coincident with the Coastal Plain 

Physiographic Province (fig. 6). The remaining 

level III ecoregions (Interior River Lowlands, Mississippi Valley Loess Plains, and Ridge and Valley) cover 

relatively small areas and are subdivisions within the 

physiographic provinces (fig. 6). 

Subdivisions of level III ecoregions (level IV) 

decrease the heterogeneity within the larger-scale 

ecoregions. Level IV ecoregions are being defined on a 

state by state basis. This level of definition was not 

available for Alabama; however, level IV ecoregions 

had been delineated for Tennessee (Griffith and others, 

1997) and were used for the subdivision of the study 

unit in that State.

Climate

Temperature is an important variable that influences the rate of most physical and chemical reactions. 

The quantity and quality of precipitation affect the 

quality of water in watersheds. The lower Tennessee 

River Basin has a temperate and warm, humid climate. 

Average temperature across the study unit ranges from 
10 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Base derived from U.S. Geological Survey,

1:2,000,000 digital line graph

INTERIOR RIVER LOWLANDS

INTERIOR PLATEAU

MISSISSIPPI

VALLEY LOESS

PLAINS

SOUTHEASTERN PLAINS

SOUTHWESTERN APPALACHIANS

RIDGE AND VALLEY

Ecoregions modified from Omernick, 1987

Figure 6. Level III ecoregions in the lower Tennessee River Basin.

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

56 to 61 oF with an average annual temperature of 

about 59 oF (U.S. Department of Commerce, 1995). 

The warmest months are July and August and the 

coolest month is January. The difference between the 

average monthly high and low temperature for the year 

is about 40 oF.

Average annual precipitation in the lower Tennessee River Basin is about 56 inches (in.) (U.S. 

Department of Commerce, 1995). The average amount 

of precipitation for individual sites in the study unit 

ranges from about 50 in. in the western part of the 

study unit to about 60 in. in the eastern part of the 

study unit (fig. 7). The increase in precipitation from 

west to east generally corresponds to the increase in 

elevation from west to east. Average rainfall amounts 

are highest during November through May, with 

March generally being the wettest month (fig. 8). 

Average rainfall amounts are lowest June through 

October (fig. 8). The month in which rainfall is lowest 

varies from site to site. August through October usually is the driest part of the year (fig. 8).

Surface Water

The main stem of the Tennessee River is highly 

regulated with few free-flowing stream reaches. Six 

large reservoirs are located on the main stem (fig. 1), 

and many additional reservoirs are located on tributaries to the main stem. Most of these reservoirs were 

constructed from the 1930’s to the 1970’s for power 

generation, navigation, flood control, and for water 

supply. The largest tributaries to the Tennessee River 

Figure 6. Level III ecoregions in the lower Tennessee River Basin.
Environmental Setting 11

JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC

MONTH

0

7

1

2

3

4

5

6

PRECIPITATION, IN INCHES

Figure 8. Average monthly precipitation at Athens, Alabama, in the lower Tennessee

River Basin, 1961-90. (Data from U.S. Department of Commerce, 1995)

Figure 8. Average monthly precipitation at Athens, Alabama, in the lower Tennessee

River Basin, 1961-90. (Data from U.S. Department of Commerce, 1995.)

TENNESSEE

ALABAMA

KENTUCKY

TENNESSEE

MISSISSIPPI

GEORGIA

88

87

86

o

o

o

36o

35o

Duck River

Elk River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock Ri v er

Beech River

Sequatchie River

Paducah

River

Kentucky

Lake

Wheeler

Lake Wilson Lake

Pickwick L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big Sandy River

Chattanooga

Columbia

Huntsville

Athens

Decatur

Florence

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

Base from U.S. Geological Survey,

Town

Creek

50

52

54

52

54

54

52

54

56

54

52

54

56

58

56

60

54

58

60

62

58

56

54

54

56

MEASUREMENT SITE

50 EXPLANATION

LINE OF EQUAL PRECIPITATION

 Interval 2 inches

Data from U.S. Department of Commerce, 1995

Figure 7. Distribution of average annual precipitation in the lower Tennessee River Basin, 1961-90.

50

Figure 7. Distribution of average annual precipitation in the lower Tennessee River Basin, 1961-90.
12 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

1995

0

6,000

2,000

4,000

1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 0

10,000

2,000

4,000

6,000

8,000

MEAN-ANNUAL DISCHARGE, IN CUBIC FEET PER SECOND

1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 0

60,000

20,000

40,000

1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995

YEAR

0

100,000

20,000

40,000

60,000

80,000

Figure 9. Long-term mean-annual streamflow for selected streams in the lower

Tennessee River Basin.

Mean-annual discharge

Mean-annual discharge

Mean-annual discharge

Mean-annual discharge

Elk River at Prospect, Tennessee

Duck River above Hurricane Mills, Tennessee

Tennessee River at Chattanooga, Tennessee

Tennessee River at Savannah, Tennessee

are the Duck and Elk Rivers, which drain areas of 

2,700 and 2,250 mi2

, respectively. Mean-annual discharge for the Tennessee River is about 35,900 cubic 

feet per second (ft3

/s) at Chattanooga, Tennessee, and 

is about 65,600 ft3/s at the mouth of the Tennessee 

River at Paducah, Kentucky. The Duck and Elk Rivers 

combined contribute about 7,700 ft3

/s, or only about 

26 percent of the 29,700 ft3

/s of flow that is gained in 

the study unit; most of the streamflow is contributed 

from river basins smaller than 1,000 mi2

.

Long-term streamflow data at selected sites 

illustrate the range of mean-annual discharges for large 

rivers in the lower Tennessee River Basin (fig. 9). The 

time series of mean-annual discharge was similar at all 

of the sites shown in figure 9. During the selected 

period (1930-95), the lowest mean-annual discharge on 

the Tennessee River occurred during 1988 (fig. 9) at 

Chattanooga and Savannah (23,000 ft3/s at Savannah). 

The largest mean-annual discharge during the selected 

period at Savannah was about 87,000 ft3

/s in 1973. 

The 1970’s were the “wettest” years at these sites with 

Figure 9. Long-term mean-annual streamflow for selected streams in the lower Tennessee 

River Basin.
Environmental Setting 13

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

1991 1992

100

100,000

200

300

400

500

700

1,000

2,000

3,000

4,000

5,000

7,000

10,000

20,000

30,000

40,000

50,000

70,000

Duck River above Hurricane Mills, Tennessee

Mean annual discharge

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

1991 1992

1,000

1,000,000

2,000

3,000

4,000

5,000

7,000

10,000

20,000

30,000

40,000

50,000

70,000

100,000

200,000

300,000

400,000

500,000

700,000

MEAN-DAILY DISCHARGE, IN CUBIC FEET PER SECOND

Tennessee River at Savannah, Tennessee

Mean annual discharge

Figure 10. Mean daily Discharge for the Tennessee River at Savannah,Tennessee, and the

Duck river above Hurricane Mills,Tennessee, water year 1992.

6 of the 10 years having streamflow above the longterm mean-annual discharge. The 1980’s were the 

“driest” 10-year period, with 3 years of streamflow 

well below the long-term mean-annual discharge 

(fig. 9).

The regulation of flow on the Tennessee River 

and the upper parts of the Elk and Duck Rivers and 

other tributaries moderates extremes that normally 

occur in streamflow. Streamflow data for the 1992 

water year (October 1 through September 30), a year 

with near average streamflow (fig. 10), show the combined effects of basin size and reservoirs. Streamflow 

in the Duck River above Hurricane Mills (2,557 mi2

) 

is minimally affected by Normandy Lake, which is 

located about 220 mi upstream; storm peaks generally 

are followed by smooth recessions in discharge 

(fig. 10). Streamflow in the Tennessee River at Savannah (33,140 mi2) is affected by several reservoirs 

upstream, primarily Pickwick Lake. Storm peaks on 

the hydrograph generally are broader and the corresponding recessions are somewhat slower than for the 

same storms affecting the Duck River (fig. 10). The 

hydrograph for Savannah also shows peaks and recessions resulting from upstream reservoir operations. 

Streamflow response to changes in releases from reservoirs generally are more rapid than response to 

storm events. 

Figure 10. Mean-daily discharge for the Tennessee River at Savannah, Tennessee, and the Duck 

River above Hurricane Mills, Tennessee, water year 1992.
14 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Reservoir operations also affect longer periods 

of streamflow in addition to short-term releases. 

Streamflow was generally lower than average during 

July through October in the Duck River as a result of 

less precipitation and runoff. However, streamflow at 

Savannah was near the mean-annual discharge 

between July and October (fig. 10). Near average 

streamflow during these months was maintained by 

releases from Pickwick Lake to generate power during 

the summer months.

Ground Water

Principal aquifers in the lower Tennessee River 

Basin are the Cretaceous sand, Pennsylvanian sandstone, Mississippian carbonate, and Ordovician carbonate aquifers (fig. 11). The areal extent of these 

aquifers in the study unit generally corresponds to the 

principal geologic units. Ground-water flow in the 

principal aquifers in the study unit generally is along 

relatively short flow paths through solution openings, 

bedding planes, joints, fractures in bedrock, and 

unconsolidated sediments. The amount of flow to a 

deeper, regional ground-water-flow system from the 

principal aquifers is relatively small.

Sediments of predominantly Cretaceous age, 

and minor Quaternary-age alluvium and Tertiary-age 

sediments, which consist of unconsolidated sand, silt, 

clay, and minor gravel constitute the Cretaceous sand 

aquifer (fig. 11), which is confined in most places. 

Recharge to the aquifer is from precipitation on sandy 

units in the outcrop areas. Ground water flows through 

the primary porosity of this aquifer. East of the Tennessee River, ground water in the Cretaceous sand 

aquifer moves along short flow paths and discharges 

within the Tennessee River Basin (Brahana and others, 

1986b). Ground water west of the Tennessee River 

also discharges to streams in the study unit, but a component of ground water flows to the west, along 

regional flow paths, in the direction of the regional dip 

of the sediments. Ground-water gradients and velocities generally are lower in the Cretaceous sand aquifer 

than in other hydrogeologic settings in the study unit.

Sandstones and conglomerates are the primary 

water-bearing units that constitute the Pennsylvanian 

sandstone aquifer (fig. 11). These rocks generally have 

low permeability, and ground water flows primarily 

through fractures in these rocks (fig. 12). The number, 

size, and density of fractures decreases with depth, 

limiting the regional component of ground-water flow. 

Flow paths typically are short and ground water discharges to streams and springs. Recharge to the aquifers occurs where precipitation falls on outcrops of 

these units and where streambeds intersect these units 

(Brahana and others, 1986a). A shale confining unit 

between the Pennsylvanian sandstone aquifer and the 

underlying Mississippian carbonate aquifer retards the 

movement of ground water between these aquifers 

(fig. 12).

The Mississippian carbonate aquifer is the most 

areally extensive and productive aquifer in the lower 

Tennessee River Basin (fig. 11). Ground water in this 

aquifer flows in solution openings along bedding 

planes, joints, and fractures. These openings and the 

zone of dynamic ground-water circulation generally 

are at depths less than 300 ft below land surface 

(fig. 12). Recharge to the Mississippian carbonate 

aquifer is from precipitation percolating through the 

overlying regolith to the bedrock aquifer. The regolith 

can store large amounts of water that is slowly transmitted downward into the bedrock aquifer. Locally, the 

regolith may contain abundant gravel and is a productive aquifer. Generally, flow paths are short and 

ground-water gradients are relatively steep; ground 

water moves rapidly and discharges to streams and 

springs. The Mississippian carbonate aquifer is underlain by the Devonian-age Chattanooga Shale (fig. 3), a 

regional confining unit that effectively limits the 

movement of ground water between the Mississippian 

carbonate and the underlying Ordovician carbonate 

aquifers.

Ground water in the Ordovician carbonate aquifer (fig. 11) flows primarily in solution openings along 

bedding planes, joints, and fractures. These solution 

openings are most common and shallow ground-water 

flow occurs primarily within about 300 ft of land surface. Shaly beds and bentonite layers present in the 

Ordovician rocks retard the downward movement of 

ground water, but locally, joints in or erosion of these 

layers allows deeper circulation of ground water 

(fig. 12). The limestones that make up these aquifers 

are predominantly calcite, and contain little insoluble, 

soil-forming material and little or no regolith (generally less than 20 ft) overlies the aquifer. Flow paths are 

short and ground water moves rapidly and discharges 

to streams and springs.

Surface- and Ground-Water Interactions

Ground-water discharge to streams is a significant component of streamflow and affects the water 

quality of streams in the lower Tennessee River Basin. 
Environmental Setting 15

Areal extent Aquifer Lithology and hydrogeology

Cretaceous sand

 aquifer

Unconsolidated sand, silt, clay, and 

gravel. Ground-water flow occurs 

in intergranular pore spaces. Flow 

paths are short to very long. Wells in 

these aquifers produce enough water 

for domestic use and locally small 

public supplies. Wells can yield up 

to 100 gallons per minute. 

Pennsylvanian 

sandstone

 aquifer

Sandstone, conglomerate, siltstone, 

shale, and coal. Aquifers consist primarily of sandstone and conglomerate. Permeability of these formations 

is low and ground-water flow generally occurs along fractures. Artesian 

conditions often occur. Flow paths 

generally are short, small springs are 

common. Well yields typically are 

low but yield enough for domestic 

use.

Mississippian 

carbonate

aquifer

Limestone and chert. Aquifers occur 

primarily in massive bedded limestone formations. Locally, productive aquifers are present in chert 

gravels present in regolith overlying 

bedrock. Most ground-water flow 

occurs in solution channels formed 

in joints and bedding planes. Flow 

paths generally are short, moderately large springs are common. 

Aquifers used for domestic and public supply. Well yields range from 

low to very high (more than 3,000 

gallons per minute). 

Ordovician

carbonate 

aquifer

Predominantly limestone, minor 

dolomite. Most ground-water flow 

occurs in solution channels formed 

in joints and bedding planes. 

Ground-water flow paths typically 

are short and springs are common. 

Well yields generally are between 2 

to 20 gallons per minute but can be 

as high as 300 gallons per minute.

Figure 11. Principal aquifers in the lower Tennessee River Basin. (Modified from King and Beikman, 1974)

Figure 11. Principal aquifers in the lower Tennessee River Basin. (Geology modified from King 

and Beikman, 1974.)
16 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin APPROXIMATELY 600 FEET

APPROXIMATELY 5 MILES

 NOT TO SCALE

Fractured Pennsylvanian

sandstone, conglomerate,

shale and coal

Mississippian shale and

limestone. Solution openings

are present in limestone

WEST EAST CUMBERLAND ESCARPMENT

Stream

valley

Springs

Solution Spring

openings

Recharge Recharge

Modified from Gaydos and others, 1982

Recharge

APPROXIMATELY 300 FEET

APPROXIMATELY 3 MILES

 NOT TO SCALE

Springs

Water level

Recharge

Stream

Clay and chert regolith

Dynamic flow along zones of 

secondary permeablility

Solution openings

Modified from Brahana and Bradley, 1986b

APPROXIMATELY 1,500 FEET

ORDOVICIAN LIMESTONE

APPROXIMATELY 200 FEET

Figure 12. Conceptual models of ground-water occurrence in bedrock aquifers in the

lower Tennessee River Basin.

NOT TO SCALE

Regolith

Solution openings

Stream

Recharge

Recharge

Modified from Zurawski, 1978

Bentonite bed

GROUND-WATER FLOW

 DIRECTION

EXPLANATION

Pennsylvanian sandstone aquifer

Mississippian carbonate aquifer

Ordovician carbonate aquifer

Figure 12. Conceptual models of ground-water occurrence in bedrock aquifers in the lower 

Tennessee River Basin.
Environmental Setting 17

Water-quality properties that often are affected by 

ground-water discharge to streams include pH, temperature, dissolved oxygen, and concentrations of dissolved inorganic constituents. During dry periods of 

the year, ground-water discharge to springs and 

streams provides much or all of the flow in streams. 

Hydrograph-separation and baseflow estimation methods were applied to streamflow data for 

selected streams in the lower Tennessee River Basin to 

estimate the contribution of ground water to streamflow. To cover a broad range of hydrologic conditions, 

surface-water discharge records of 10 or more years 

were selected for analysis; a few shorter periods of 

record also were used (table 1). The computer program 

RORA (Rutledge, 1998), which automates the Rorabaugh (1964) and Daniel (1976) method, estimates 

ground-water recharge using the recession-curve-displacement method. The computer program PART estimates baseflow using streamflow partitioning 

(Rutledge, 1998). Generally, the estimated groundwater discharge (PART) is less than the estimated 

recharge (RORA); this difference is attributed to riparian evapotranspiration if ground-water withdrawals are 

negligible (Rutledge, 1998). For the purposes of this 

report, the results of both programs are termed baseflow estimates and results from RORA represent an 

upper limit of the baseflow estimate. Both programs 

require the assumptions that the aquifers contributing 

baseflow are isotropic and uniform and that the 

streams and aquifers are not significantly affected by 

withdrawals, discharges, or impoundments. All of 

these assumptions are not met, particularly the first, in 

the selected stream basins and throughout much of the 

lower Tennessee River Basin; therefore, the results of 

this analysis are considered estimates.

Estimates of baseflow calculated by both programs (table 1) are considerably higher than estimates 

of net annual recharge for average flow years reported 

for the same streams (Hoos, 1990) calculated by the 

manual Rorabaugh-Daniel hydrograph-separation 

method. However, estimates of baseflow calculated by 

PART fall within the range reported for streams with 

watersheds underlain by the Pennsylvanian, Mississippian, and Ordovician aquifers using the manual baseflow estimation technique (Zurawski, 1978). Although 

estimates differ between the methods and studies 

(Zurawski, 1978; Hoos, 1990), the ranking of each 

principal aquifer setting based on estimates of baseflow is similar for all methods. Baseflow (groundwater discharge) is highest for basins underlain by the 

Mississippian aquifers and lowest in basins underlain 

by the Cretaceous sand aquifer (table 1). Baseflow in 

basins underlain by the Cretaceous sand aquifer is low, 

in part, because of loss of ground water to a regional 

flow system. Baseflow in basins underlain by the 

Ordovician carbonate aquifer and Pennsylvanian sandstone aquifer is about the same. Estimates for basins 

underlain by both Mississippian carbonate and Pennsylvanian sandstone aquifers were slightly higher than 

basins underlain by Pennsylvanian sandstone aquifer 

only (table 1).

Mean-annual runoff (inches of water discharged 

per unit area) in the study unit ranges from about 

30 in/yr [about 2 (ft3

/s)/mi2] in the area near Guntersville Lake to about 18 in. [about 1 (ft3/s)/mi2] in the 

northwestern part of the study unit (fig. 13). Runoff is 

affected by climate (temperature and precipitation), 

topography (slope), and soils. The decrease in runoff 

from east to west generally corresponds to a decrease 

in the amount of precipitation across the study unit 

(fig. 7). In the eastern part of the study unit, about 

45 percent of rainfall becomes runoff and in the western part about 35 percent does. The movement of 

ground water along a regional flow path in the Coastal 

Plain may contribute to the decrease in runoff across 

the study unit.

Cultural Setting

Cultural setting includes human activities that 

affect natural surface- and ground-water quality. 

Human activities affect water quality through input of 

physical and chemical constituents to a water body or 

to land surface in a watershed, modifications to the 

hydrologic system, such as reservoirs and impoundments, and surface- and ground-water use. Inputs of 

constituents from human activities to a watershed can 

be characterized as one of two types, point or nonpoint 

sources. Nonpoint sources to surface and ground water 

may be a mix of cultural and natural sources and 

include runoff and infiltration of constituents from 

urban and agricultural areas and atmospheric deposition of constituents. Whereas the distribution and magnitude of point sources are generally well documented, 

the distribution and magnitude of nonpoint sources are 

more difficult to quantify. Land-use data are often used 

as a surrogate for the distribution of nonpoint sources 

in water-quality studies.

Reservoirs, water use, land-use data, and inputs 

of selected constituents in the lower Tennessee River 
1

8EnvironmentalSettingandWater-QualityIssuesinthe

LowerTennesseeRiverBasin

Table 1. Streamflow and baseflow estimates for selected streams in the lower Tennessee River Basin[ID, identification number; mi2, square miles; ft3/s, cubic feet per second; in/yr, inches per year; C, Cretaceous sand aquifer; P, Pennsylvanian sandstone aquifer; M, MOrdovician carbonate aquifer]

Station name

Principal 

aquifer

Station ID Drainage area, mi2 Period of record Reces- sion index Mean streamflow ft3/s in/yr

ra

   i

aThe lower value of the ranges was estimated using streamflow partitioning (PART computer program, Rutledge, 1998); the higher value of the ranges was estim

displacement (RORA computer program, Rutledge, 1998).

bFrom Hoos, 1990, table 2, average net annual recharge.

Clarks River at Almo, Ky. C 03610200 134 1983-95 30 180 18.2 3.Crow Creek at Bass, Ala. P 03572110 131 1976-95 21 281 29.2 13.4Town Creek near Geraldine, Ala. P 03572900 141 1992-94 33 336 32.4 13.Flint Creek near Falkville, Ala. M & P 03576500 84 1993-96 22 142 23.1 11.Sequatchie River near Whitwell, Tenn. M & P 03571000 402 1921-93 35 752 25.4 15.Paint Rock River near Woodville, Ala. M & P 03574500 320 1936-96 28 689 29.2 12.Shoal Creek at Iron City, Tenn. M 03588500 348 1926-94 63 653 25.5 14.Buffalo River near Flatwoods, Tenn. M 03604000 447 1921-97 54 768 23.3 14.Buffalo River below Lobelville, Tenn. M 03604400 702 1928-93 55 202 23.3 14.Indian Creek near Madison, Ala. M 03575830 49 1976-96 34 70 19.3 10.Flint River near Chase, Ala. M 03575000 342 1931-80 48 558 22.2 11.Big Nance Creek at Courtland, Ala. M 03586500 166 1989-97 26 350 28.7 10.Piney River at Vernon, Tenn. M 03602500 193 1926-93 55 315 22.2 14.West Flint Creek near Oakville, Ala. M 03577000 88 1993-96 20 168 26.1 12.Elk River at Prospect, Tenn. M & O 03584600 1,805 1920-93 40 3,090 23.3 11.Duck River above Hurricane Mills, Tenn. M & O 03603000 2,557 1926-93 48 4,106 21.8 11.Carters Creek at Butler Road at Carters Creek, Tenn. O 03600088 20 1987-97 30.1 34 22.6 11.Garrison Fork above L&N Railroad at Wartrace, Tenn. O 03597210 86 1990-97 21.5 169 26.9 10.E. Fork Mulberry Creek below Jack Daniels Distillery 

at Lynchburg, Tenn.

O 03580995 23 1988-93 45.5 48 28.1 14.

Wartrace Creek below County Road at Wartrace, Tenn. O 03597590 36 1990-97 16.7 72 27.3 7.4
Environmental Setting 19

MISSISSIPPI

GEORGIA

88

87

86

o

o

o

36o

35o

Duck River

Elk River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock Ri v er

Beech River

Sequatchie River

Paducah

River

Kentucky

Lake

Wheeler

Lake

Wilson Lake

Pickwick L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big Sandy River

Chattanooga

Columbia

Huntsville

Decatur

Florence

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

Base from U.S. Geological Survey,

18

18

18

20

22

24

25

25

24

26

26

30

28

26

EXPLANATION

Figure 13. Major drainages and mean-annual surface-water runoff, 1951-80,

in the lower Tennessee River Basin.

Data from Gebert and others, 1987

18

LINE OF EQUAL RUNOFF Interval 2 inches

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

Basin are described and quantified in the following 

sections. Inputs of nitrogen, phosphorus, and pesticides were estimated because occurrence and distribution of these constituents are largely influenced by 

human activities.

Reservoirs 

Reservoirs on the main stem of the Tennessee 

River and its tributaries are used for power generation, 

navigation, flood control, water supply, and recreation. 

Wilson Lake (fig. 1), completed in 1924, was the first 

reservoir constructed on the main stem in the study 

unit. Four additional reservoirs were completed on the 

main stem by 1944. Nickajack Lake, completed in 

1967, was last reservoir constructed on the main stem 

in the lower Tennessee River Basin. The BarkleyKentucky Canal, which is used for navigation and 

power generation at Kentucky Lake, allows interbasin 

transfer of water between the lower Tennessee River 

Basin and the Cumberland River Basin. Interbasin 

transfer of water also occurs between the Mobile and 

lower Tennessee River Basins via the TennesseeTombigbee Waterway near Pickwick Lake.

Reservoirs affect water quality by acting as sinks 

for sediment, nutrients, metals, and hydrophobic 

organic compounds. Reservoirs also affect stream 

water temperature, dissolved oxygen concentrations, 

and concentrations of other water-quality constituents. Hydraulic residence time in reservoirs is an 

important factor in the effect of reservoirs on water 

quality. The average hydraulic residence time for main 

stem reservoirs ranges from about 4 to 35 days; 

Figure 13. Major drainages and mean-annual surface-water runoff, 1951-80, in the lower

Tennessee River Basin.
20 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

whereas the average residence time of five tributary 

reservoirs maintained by the Tennessee Valley Authority ranges from about 10 to 500 days (E.A. Thornton, 

Tennessee Valley Authority, written commun., 1998). 

These tributary reservoirs are more likely to function 

as sinks for sediment and nutrients associated with 

sediment or for aquatic-plant uptake of nutrients 

because of longer residence times. The storage volume 

of the six reservoirs on the main stem of the Tennessee 

River is about 6.7 million acre-ft and the tributaries to 

the Tennessee River have a total storage volume of 

about 800,000 acre-ft (E.A. Thornton, Tennessee Valley Authority, written commun., 1998).

Water Use

Total average water use in the lower Tennessee 

River Basin was about 5,380 million gallons per day 

(Mgal/d) in 1995 (U.S. Geological Survey, 1997). 

Thermoelectric use accounted for about 4,700 Mgal/d, 

and most of this water was returned to streams and reservoirs in the basin. The second largest water-use category was industrial water use, about 380 Mgal/d with 

about 350 Mgal/d of the total amount withdrawn from 

surface-water sources (fig. 14). Most of the thermoelectric and much of the industrial surface-water use 

occurs along the main stem of the Tennessee River. 

Public supply was the third largest water-use category, 

about 220 Mgal/d; most of this, about 160 Mgal/d, was 

withdrawn from surface-water sources. Water used for 

livestock amounted to about 30 Mgal/d and commercial water use was about 20 Mgal/d; most of the water 

for these uses was withdrawn from surface-water 

sources. Domestic, self-supplied water use was about 

20 Mgal/d and was exclusively from ground-water 

sources.

The location and size of public-water supply 

surface-water withdrawals in the study unit are shown 

in figure 15a; withdrawal amounts grouped by subunit 

and water body are shown in figure 15b. The main 

stem of the Tennessee River supports the largest 

amount of public water supply (fig. 15b), including the 

largest surface-water public supply in the study unit, 

the City of Decatur, Alabama, which withdrew about 

28 Mgal/d in 1995. The City of Huntsville, Alabama, 

withdrew about 22 Mgal/d in 1995 from the Tennessee 

River. The Duck and Elk Rivers and their tributaries 

supplied about 50 Mgal/d for public supply. Withdrawals from these streams are shown as mixed Eastern Highland Rim/Nashville Basin in figure 15b, 

because the drainage areas contributing to the streams 

at the withdrawal point include parts of both of these 

subunits. Withdrawals from the other tributaries in the 

study unit are associated with a single subunit, and 

accounted for about 46 Mgal/d combined.

The location and size of public-water supply 

ground-water withdrawals in the study unit are shown 

in figure 16a; withdrawal amounts of both publicsupply and self-supplied domestic use by subunit are 

shown in figure 16b. Domestic and public supply 

ground-water use were highest in the Eastern Highland Rim subunit (fig. 16b), where about 40 Mgal/d 

was withdrawn from the Mississippian aquifers in 

1995 (35 Mgal/d for public supply, 5 Mgal/d domestic use). The City of Huntsville, Alabama, located in 

this subunit, is the largest ground-water public supply 

in the study unit (fig. 16a); ground water makes up 

40 percent of the water used to supply the city’s 

needs. About 14 Mgal/d was withdrawn from relatively shallow wells (maximum depth 125 ft) and a 

large spring. About 14 Mgal/d of ground water was 

withdrawn in both the Western Highland Rim and the 

Coastal Plain subunits (fig. 16b); domestic water use 

accounted for about 30 percent of the water used in 

the Western Highland Rim, but only about 15 percent 

of the water used in the Coastal Plain. Total groundwater use in each of the remaining subunits was about 

5 Mgal/d or less in 1995. Ground-water withdrawals 

Industrial Public supply Livestock Irrigation Domestic Commercial

400

0

50

100

50

150

200

250

300

350

FRESHWATER WITHDRAWALS, IN MILLION GALLONS PER DAY

EXPLANATION

Surface water

Ground water

Figure 14. Estimated water use by withdrawal

type in the lower Tennessee River Basin, 1995

(U.S. Geological Survey, 1997). 

WITHDRAWAL TYPE

Figure 14. Estimated water use by withdrawal type in the 

lower Tennessee River Basin, 1995. (U.S. Geological 

Survey, 1997.)
Environmental Setting 21

88

87

86

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

Base from U.S. Geological Survey,

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

Duck River

Elk

River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock Ri v er

Beech River

Sequatchie River

River

Kentucky

Lake

Wheeler

Lake

Wilson Lake

Pickwick L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big Sandy River

LESS THAN 1

1-4.9

5-14.9

15-30

SURFACE-WATER WITHDRAWALS,

 IN MILLION GALLONS PER DAY

EXPLANATION

Figure 15. (A) Location and size of public-supply surface-water withdrawals and (B) summary

of withdrawals by subunit and water body in the lower Tennessee River Basin, 1995.

Paducah

Chattanooga

Columbia

Huntsville

Decatur

Florence

stem

main

River

Tennessee

Basin

Rim/Nashville

Highland

Eastern

Mixed

Plain

Coastal Transition

Rim Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim Highland

Eastern

Valleys

and Escarpment

Plateau

Plateau

Cumberland

Ridge

and

Valley 0

70

10

20

30

40

50

60

SURFACE-WATER WITHDRAWALS, IN MILLION GALLONS PER DAY

SUBUNIT

B.

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

A.

Figure 15. (A) Location and size of public-supply surface-water withdrawals and (B) summary of withdrawals by 

subunit and water body in the lower Tennessee River Basin, 1995.
22 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35 o

Base derived from U.S. Geological Survey,

1:2,000,000 digital line graph

Huntsville

Cumberland

Plateau

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

KENTUCKY

TENNESSEE

Figure 16. (A) Location of public-supply ground-water withdrawals and (B) distribution of publicsupply and domestic withdrawals by subunit in the lower Tennessee River Basin, 1995

A.

B.

Plain

Coastal Transition

Rim Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim Highland

Eastern

Valleys

and Escarpment

Plateau

Plateau

Cumberland

Ridge

Valley and 0

50

10

20

30

40

GROUND-WATER WITHDRAWALS, IN MILLION GALLONS PER DAY

EXPLANATION

PUBLIC SUPPLY

DOMESTIC USE

SUBUNIT

EXPLANATION

PUBLIC-SUPPLY GROUND-WATER

 WITHDRAWALS, IN MILLIONS OF

 GALLONS PER DAY

5-15

1-4.9

LESS THAN 1

Plateau

Escarpment

and

Valleys

subunit

Valley

and 

Ridge

subunit

Eastern

Highland

Rim

subunit

Inner

Nashville

Basin

subunit

Outer

Nashville

Basin

subunit

Western

Highland

Rim

subunit

Coastal

Plain

subunit

Transition

subunit

Cumberland

Plateau

subunit

Cumberland

Plateau

subunit

Figure 16. (A) Location and size of public-supply ground-water withdrawals and (B) distribution of 

public-supply and domestic withdrawals by subunit in the lower Tennessee River Basin, 1995.
Environmental Setting 23

88

87

86

o

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

Base from U.S. Geological Survey,

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

Duck

River

Elk

River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock

Ri v er

Beech River

Sequatchie River

River

Kentucky

Lake

Wheeler

Lake Wilson Lake

Pickwick

L ake

Tennessee

River

Woods

Reservoir

Normandy Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big

Sandy River

EXPLANATION

WASTEWATER DISCHARGE, IN MILLION GALLONS PER DAY

LESS THAN 1

GREATER THAN 1

Figure 17. Location of wastewater dischargers, and relative size of discharge,

in the lower Tennessee River Basin, 1995.

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

may induce recharge or reverse hydraulic gradients, 

which could have implications for water quality.

Wastewater Discharge

Wastewater and stormwater discharges are the 

primary point-source discharges to streams and rivers 

in the lower Tennessee River Basin. Wastewater discharge to streams in the lower Tennessee River Basin 

were estimated using effluent monitoring data 

reported to State agencies by permitted wastewater 

dischargers (J. Hughes, Tennessee Department of 

Environment and Conservation, written commun., 

1998; M. Rief and T. Cleveland, Alabama Department 

of Environmental Management, written commun., 

1998; V. Prather, Kentucky Department of Environmental Protection, written commun., 1998; G. Odom, 

Mississippi Department of Environmental Quality, 

written commun., 1998). Mean-daily flow data for 

1992 or 1995 were available for 264 permitted dischargers (fig. 17), including all of the dischargers that 

were classified as major dischargers. In general, a 

municipal facility discharging more than 1 Mgal/d, or 

Figure 17. Location of wastewater dischargers, and relative size of discharge, in the lower Tennessee River Basin, 1995.
24 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

an industrial facility with specific process wastewater 

of concern, is considered to be a major discharger; others are classified as minor dischargers. Many additional wastewater dischargers are permitted, but 

because flow data were not available in digital format, 

they were not included in this estimate. These discharges represent a small percentage of the total 

wastewater discharged to streams in the lower Tennessee River Basin (S. Fishel, Tennessee Department of 

Environment and Conservation, written commun., 

1998). 

Facilities discharging 1 Mgal/d or more contributed about 90 percent of the 13,396 Mgal/d of wastewater effluent from the 264 dischargers. Most of the 

discharges (about 13,300 Mgal/d) were to the main 

stem of the Tennessee River (fig. 17). About 

66 Mgal/d of wastewater was discharged to streams in 

the Elk River Basin and about 17 Mgal/d was discharged to streams in the Duck River Basin. Of the 

total amount of wastewater discharged, industrial and 

power generation (federal) facilities accounted for 

about 99 percent of the total effluent from permitted 

facilities in the study unit. Much of this water (about 

88 percent) was used for cooling at power generation 

facilities and at manufacturing plants, and the predominant effects on water quality are on water temperature 

and dissolved oxygen concentrations. Municipal 

wastewater discharges totaled about 135 Mgal/d, with 

21 Mgal/d of that (about 15 percent) discharged to the 

Elk and Duck River Basins.

Nutrient loads were estimated for the 264 dischargers with flow data in digital format. Generally, 

concentration data for total nitrogen and phosphorus in 

effluent were not reported, so average concentration 

values were used for the various types of treatment 

facilities (S. Fishel, Tennessee Department of Environment and Conservation, oral commun., 1998; 

National Oceanic and Atmospheric Administration, 

1993). The estimated total nitrogen wastewater load 

discharged to streams throughout the lower Tennessee 

River Basin was about 13,430 tons in 1995. About 

68 percent of the total nitrogen load was from facilities 

discharging a mean of 1 Mgal/d or more. Slightly 

more than half of the total nitrogen load was discharged directly into Wheeler Reservoir on the main 

stem. About 4 percent of the total nitrogen load was 

discharged into streams in the Elk and Duck River 

Basins combined. Although municipal facilities contributed about 1 percent of the flow from wastewater 

discharges, they contributed about 23 percent of the 

total nitrogen load in wastewater. 

The estimated total phosphorus load from 

wastewater discharged within the study unit was about 

770 tons in 1995. About 40 percent of the phosphorus 

load was discharged directly into Wheeler Reservoir 

on the main stem. About 14 percent of the total phosphorus load was discharged into the Elk and Duck 

River basins. Municipal wastewater effluent contributed about 93 percent of the total phosphorus load in 

wastewater.

Population, Land Use, and Land Cover

About 1.5 million people (1995) reside in the 

study unit. Huntsville, Alabama (160,000), 

Chattanooga, Tennessee (152,000), and Decatur, Alabama (52,000), are the largest urban areas (U.S. 

Department of Commerce, 1997). Much of the population in the study unit is located in counties along the 

Tennessee River in northern Alabama (fig. 18), with 

much of this area lying within the Eastern Highland 

Rim. About 38 percent of the population is located in 

the Eastern Highland Rim (table 2), about 14 percent 

in the Coastal Plain, 14 percent in the Western Highland Rim, and 13 percent is located in the Inner and 

Outer Nashville Basin combined (table 2). The 

remaining 20 percent of the total population is distributed across the Plateau Escarpment and Valleys, Cumberland Plateau, Transition, and Valley and Ridge. 

Between 1980 and 1995 the population in the study 

unit grew by about 15 percent. The largest increases in 

population (up to 20 percent) between 1980 and 1995 

occurred in the Inner and Outer Nashville Basin and 

the Eastern Highland Rim.

Land use in the lower Tennessee River Basin 

largely reflects the geology and physiography of the 

study unit and the distribution of people (fig. 19). 

About 51 percent of the study unit is forested land 

(table 2) based on 1992 land-use data. The amount of 

forested land by subunit in the lower Tennessee River 

Basin ranges from about 27 percent in the Eastern 

Highland Rim to 68 percent in the Plateau Escarpment 

and Valleys. Forested land is the predominant land 

cover in six of the nine subunits (table 2), with the 

largest forested areas located in the Western Highland 

Rim, Plateau Escarpment and Valleys, and Transition 

subunits, where topographic relief is the highest. Agricultural land (pasture and cultivated land) accounts for 

about 40 percent of the land use in the study unit 

(table 2); agriculture by subunit ranges from 

25 percent of the Plateau Escarpment and Valleys to 

63 percent of the Inner Nashville Basin (table 2). 
Environmental Setting 25

86

87

88

36

35

o

o

o

o

o

EXPLANATION

MOORE

COFFEE

GRUNDY

MARION

SEQUATCHIE

BLEDSOE

CUMBERLAND

VAN BUREN

HAMILTON

FRANKLIN

JACKSON MADISON

DEKALB

DADE

WALKER

MARSHALL

MORGAN

CULLMAN

BLOUNT

ETOWAH

LINCOLN

LIMESTONE

LAWRENCE

FRANKLIN

COLBERT

LAUDERDALE

TISHOMINGO

ALCORN

PRENTISS

BEDFORD

MARSHALL

GILES WAYNE LAWRENCE HARDIN

MCNAIRY

CHESTER

HENDERSON

DECATUR

PERRY

LEWIS MAURY

WILLIAMSON

RUTHERFORD

HICKMAN

HUMPHREYS

DICKSON

HOUSTON

HENRY

CARROLL

BENTON

STEWART

CALLOWAY

MARSHALL

GRAVES

MCCRACKEN

LIVINGSTON

LYON

TRIGG

MARION

WINSTON

1:2,000,000 digital line graph

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Figure 18. Population in the lower Tennessee River Basin, by county, 1995.

Base from U.S. Geological Survey,

Huntsville Decatur

Florence

Chattanooga

Paducah

Columbia

150- 300

100- 149

50- 99

25- 49

LESS THAN 25

POPULATION, IN THOUSANDS

 (Data from U.S. Department of

 Commerce, 1997)

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

Pasture land accounts for about 72 to 97 percent of all 

agricultural land throughout the lower Tennessee River 

basin, and is the predominant land use in the Inner and 

Outer Nashville Basin and in the Eastern Highland 

Rim (table 2). Cultivated land generally is located in 

the Eastern Highland Rim, Cumberland Plateau, Inner 

Nashville Basin, and Coastal Plain (table 2 and fig. 19) 

where relief is lowest. The Eastern Highland Rim contains the largest percentage of cultivated land (16 percent) in the study unit (table 2); less than 6 percent of 

the land in other subunits is cultivated. Urban areas in 

the lower Tennessee River Basin represent 1 percent or 

less of the land use in most subunits (table 2) and 

about 1 percent of the study unit overall. Exceptions 

are the Valley and Ridge with about 11 percent urban 

land (the outlying area of Chattanooga, Tennessee), 

and the Eastern Highland Rim with about 3 percent 

urban land. The remaining 8 percent of the study unit 

includes open water and other land uses (mined land 

and wetlands).

The cultural activities related to land use most 

likely to have a widespread effect on water quality in 

the lower Tennessee River Basin are animal and 

rowcrop agriculture. County-level data for crop production and livestock population from the 1992 Census of Agriculture (U.S. Department of Commerce, 

1994) were converted to estimates by subunit through 

a land-use weighting algorithm. This weighting algorithm apportions the county level data to each subunit 

based on the portion of cultivated land or pasture land, 

by county, encompassed within each subunit.This procedure required the assumption that different crop 

types and livestock were evenly distributed across 

their respective land use in each county.

Figure 18. Population in the lower Tennessee River Basin, by county, 1995.
26 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Corn, soybeans, cotton, and wheat were the predominant crops grown in the lower Tennessee River 

Basin in 1992 (table 3). Corn acreage was the largest 

of the crop areas in 1992 and accounted for about 

34 percent of the total harvested acreage of these crops 

(U.S. Department of Commerce, 1994). Soybean acreage accounted for about 32 percent, cotton about 

23 percent, and wheat about 11 percent of the total 

harvested acreage of all four crops in 1992.

Harvested acreage for each crop type was normalized by the area of each subunit to illustrate the relative intensity of the agricultural activity by subunit in 

1992 (fig. 20). The Eastern Highland Rim and the 

Coastal Plain ranked highest with respect to the number of cultivated acres per square mile. Cotton was 

grown primarily in the Eastern Highland Rim and was 

the largest crop both in total acreage in a subunit 

(table 3) and acreage per square mile (fig. 20). Corn 

and soybeans were grown in all of the subunits. The 

Coastal Plain, Eastern Highland Rim, and Inner Nashville Basin ranked highest in farming intensity for corn 

and soybeans and also supported the greatest amount 

of harvested acreage of wheat per square mile.

County-level 1992 livestock population data 

were used to estimate the number of livestock by subunit (table 3). These data also were normalized by the 

area of each subunit to illustrate the relative intensity 

of livestock production by subunit (fig. 21). About 

42 million chickens, 0.9 million cattle, and 0.3 million 

hogs were raised in the study unit in 1992 (table 3). 

The Cumberland Plateau ranked highest with respect 

to the number of head per square mile (fig. 21). 

Chicken production was the largest livestock activity 

in the Cumberland Plateau, which supported about 

8,000 chickens per square mile. The Valley and Ridge, 

Eastern Highland Rim, Inner Nashville Basin, and Plateau Escarpment and Valleys supported more than 

2,000 chickens per square mile. The Inner and Outer 

Nashville Basin ranked first and second in cattle production and supported more than twice as many cows 

per square mile as did the remaining subunits. The 

Coastal Plain ranked first in hog production, with 

about twice as many hogs per square mile as the second highest-ranking subunit.

Table 2. Summary of land use and population by subunit in the lower Tennessee River Basin, 1992

[Data from Tennessee Valley Authority (Frank Sagona, Tennessee Valley Authority, written commun., 1998). Land cover data were derived spectrally from 

satellite imagery (from the period 1989-92), and ground truthed using infrared aerial photography. Boundaries for certain land-use classifications (urban and 

wetland areas) were digitized from topographic maps. Population data from U.S. Department of Commerce, 1997; <, less than]

Percentage of subunit in major land use category

Subunit

Area, in

square

miles

Percent

of study

unit area 

Population,

 in

thousands,

1995

Forest Cultivated Pasture Urban Open

water Other

Coastal Plain 2,395 12 220 44 5 41 1 1 8

Transition 1,709 7 36 65 2 24 <1 3 6

Western Highland Rim 5,154 27 207 64 3 25 1 5 2

Outer Nashville Basin 2,093 11 102 41 3 53 1 1 1

Inner Nashville Basin 569 3 93 34 6 57 1 1 1

Eastern Highland Rim 3,423 18 584 27 16 41 3 3 10

Plateau Escarpment and Valleys 1,892 11 123 68 3 22 <1 6 1

Cumberland Plateau 2,173 10 119 57 6 36 <1 1 <1

Valley and Ridge 160 1 33 51 1 34 11 2 1

Lower Tennessee River Basin 19,568 100 1,517 51 6 34 1 3 5
Environmental Setting 27

88

87

86

o

o

o

36o

35o

1:2,000,000 digital line graph

EXPLANATION

Base from U.S. Geological Survey,

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

OPEN WATER

PASTURE

CULTIVATED

FOREST

URBAN

OTHER

Figure 19. Land use in the lower Tennessee River Basin.

Land use and land cover digital data provided by Tennessee

Valley Authority (Frank Sagona, TVA, written commun.,

1998). Land cover data were derived spectrally from satellite

imagery (from 1989-92), and ground truthed using infrared

aerial photography. Boundaries for certain land-use classifications

(urban and wetland areas) were digitized from topographic maps.

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS
28 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Plain

Coastal Transition

Rim

Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim

Highland

Eastern

and Valleys

Escarpment

Plateau Plateau Cumberland Ridge

Valley and 0

120

20

40

60

80

100

HARVESTED ACRES PER SQUARE MILE

EXPLANATION

WHEAT

COTTON

SOYBEANS

CORN

Figure 20. Distribution of predominant crops by subunit in the lower Tennessee River Basin, 1992

(Estimates based on 1992 Census of Agriculture, U.S. Department of Commerce, 1994). 

SUBUNIT

Table 3. Estimated crop production and livestock population by subunit in the lower Tennessee River Basin, 1992

[Crops in acres harvested; livestock in number of animals. Estimates based on 1992 Census of Agriculture (U.S. Department of Commerce, 1994)]

Subunit Corn Soybeans Cotton Wheat Chickens Cattle Hogs

Coastal Plain 93,900 80,000 4,900 29,500 1,210,000 78,400 89,100

Transition 11,400 24,600 14,500 4,400 2,750,000 46,500 12,100

Western Highland Rim 61,300 30,600 26,800 13,600 811,000 175,000 69,900

Outer Nashville Basin 19,600 18,200 4,000 8,000 1,840,000 219,000 36,600

Inner Nashville Basin 12,300 9,700 10 6,500 1,740,000 63,200 9,700

Eastern Highland Rim 73,400 96,600 164,000 34,200 10,900,000 193,000 48,300

Plateau Escarpment and Valleys 19,200 22,400 540 3,400 4,990,000 55,000 17,700

Cumberland Plateau 27,700 22,600 4,500 2,900 17,300,000 99,000 40,400

Valley and Ridge 980 670 20 260 865,000 7,000 2,400

Lower Tennessee River Basin 319,780 305,370 219,270 102,760 42,406,000 936,100 326,200

Figure 20. Distribution of predominant crops by subunit in the lower Tennessee River Basin, 1992. 

(Estimates based on 1992 Census of Agriculture, U.S. Department of Commerce, 1994.)
Environmental Setting 29

0

500

50

100

150

200

250

300

350

400

450

NUMBER OF HOGS AND CATTLE PER SQUARE MILE

Plain

Coastal Transition

Rim

Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim

Highland

Eastern

Valleys

and

Escarpment

Plateau

Plateau

Cumberland

Ridge

Valley and 0

10,000

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

NUMBER OF CHICKENS PER SQUARE MILE

EXPLANATION

HOGS

CATTLE

CHICKENS

Figure 21. Distribution of predominant livestock by subunit in the lower Tennessee River

Basin, 1992 (Estimates based on 1992 Census of Agriculture, U.S. Department of

Commerce, 1994). 

SUBUNIT

Figure 21. Distribution of predominant livestock by subunit in the lower Tennessee River Basin, 

1992. (Estimates based on 1992 Census of Agriculture, U.S. Department of Commerce, 1994.)

Nonpoint-Source Nutrient Inputs

Nonpoint sources of the nutrients nitrogen and 

phosphorus include urban runoff, fertilizer application, 

failing septic tanks, livestock waste, nitrogen fixation, 

sediment and rock dissolution, and atmospheric deposition. Nutrient inputs to the study unit from atmospheric deposition, fertilizer application, livestock 

waste, and nitrogen fixation (from soybean crops) 

were estimated by subunit for 1992. The contribution 

of nutrients from failing septic tanks, urban runoff, and 

dissolution of rocks could not be estimated from available data.

Estimates of total nitrogen inputs from precipitation were derived from deposition rates for total 

nitrogen from five stations in the National Atmospheric Deposition Program/National Trends Network, 

a national network of precipitation chemistry monitoring stations operated in cooperation between State 

agricultural experiment stations, the U.S. Geological 

Survey, U.S. Department of Agriculture, and other 

governmental and private entities. Nitrogen deposition 

rates for subunits were estimated by calculating a 

weighted average deposition rate in 1992 from the five 

stations, based on their distance from the centroid of 

each subunit, and were multiplied by the subunit area 

to compute a total nitrogen input. Because phosphorus 

concentrations in precipitation generally are below the 

reporting level of the analytical method, atmospheric 

deposition is not expected to be a significant source of 

phosphorus (M.A. Nilles, U.S. Geological Survey, 

written commun., 1999); however, atmospheric deposition may contribute significant amounts of phosphorus in some regions (Harned, 1995).

Nitrogen and phosphorus inputs related to agricultural activities include fertilizer application, livestock waste, and nitrogen fixation. Estimates of inputs 

from fertilizer application were based on county sales 

data for 1991 and agricultural census data for 1987. 

The sources for these data and the methods of calculating county estimates are described in detail in 

Battaglin and Goolsby (1995). Estimates of inputs 

from livestock waste are based on the 1992 Census of 

Agriculture and estimates of nutrient content of livestock waste (U.S. Department of Commerce, 1994). 

Nitrogen fixation estimates were based on 1992 harvested acreage of soybeans, multiplied by a rate for 

nitrogen fixation (Craig and Kuenzler, 1983; U.S. 

Department of Commerce, 1994 ). County-level estimates of nutrient inputs from agricultural activities 

were converted to subunit-level estimates by weighting 

the area of cultivated and pasture land in a county and 

in each subunit.
30 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Table 4. Estimated total nitrogen and phosphorus inputs from nonpoint sources by subunit in the lower Tennessee River Basin, 

1992

[Values in tons per year. Inputs for livestock are based on 1992 Census of Agriculture (U.S. Department of Commerce, 1994)]

Nitrogen Phosphorus

Subunit

Area, 

in

square

miles

Atmospheric

deposition

Fertilizer Livestock

waste

Nitrogen

fixation

Total

nitrogen

input

Fertilizer Livestock

waste

Total

phosphorus

input

Coastal Plain 2,395 3,800 12,000 6,200 4,200 26,200 2,800 2,200 5,000

Transition 1,709 2,900 3,900 4,000 1,300 12,100 600 1,200 1,800

Western Highland 

Rim

5,154 8,900 12,000 10,000 1,600 32,500 2,700 3,300 6,000

Outer Nashville 

Basin

2,093 3,800 4,900 12,000 1,000 21,700 1,200 3,600 4,800

Inner Nashville 

Basin

569 1,000 2,900 4,200 500 8,600 700 1,200 1,900

Eastern Highland 

Rim

3,423 6,200 25,000 16,000 5,100 52,300 4,700 4,900 9,600

Plateau Escarpment and 

Valleys

1,892 3,900 3,200 5,700 1,200 14,000 600 1,800 2,400

Cumberland 

Plateau

2,173 3,300 5,900 16,000 1,300 26,500 1,000 5,000 6,000

Valley and Ridge 160 300 400 900 40 1,640 100 300 400

Lower Tennessee 

River Basin 

(total)

19,568 34,100 70,200 75,000 16,240 195,540 14,400 23,500 37,900

Estimated nitrogen inputs to the study unit from 

nonpoint sources were about 195,000 tons (table 4). 

The nitrogen input to the study unit from agricultural 

activities (fertilizer, livestock waste, and nitrogen fixation) was about 161,000 tons in 1992. Atmospheric 

deposition of nitrogen totalled about 34,100 tons in 

1992 (table 4) and contributed about 18 percent of the 

nitrogen input. Most of that input was contributed by 

livestock waste and fertilizer application; nitrogen fixation by soybeans accounted for about 8 percent of the 

nitrogen input. Although much of the nitrogen input 

from agricultural activities is taken up by crops and 

removed by harvest, some of this input may affect 

water quality, where inputs greatly exceed crop 

uptake. 

The magnitude of nonpoint-source inputs varies across the lower Tennessee River Basin. The 

distribution of nitrogen input by subunit is shown, on 

a per unit area basis, in figure 22. The Eastern Highland Rim had the largest nitrogen input in the study 

unit (table 4) and also had the highest nitrogen input 

per unit area (fig. 22). Unit-area nitrogen inputs from 

livestock waste were the largest nonpoint source of 

nitrogen in the Cumberland Plateau, the Inner and 

Outer Nashville Basin, and the Valley and Ridge, and 

accounted for at least a quarter of the nitrogen input 

for all subunits. Unit-area nitrogen inputs from fertilizer application were the largest nonpoint source of 

nitrogen in the Eastern Highland Rim and Coastal 

Plain. Unit-area nitrogen inputs from atmospheric deposition were about the same for all subunits. In the 

Transition, Western Highland Rim, and Plateau 

Escarpment and Valleys, however, atmospheric deposition accounted for about 25 percent of the nitrogen 
Environmental Setting 31

Plain

Coastal Transition

Rim

Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim

Highland

Eastern

Valleys

and

Escarpment

Plateau

Plateau

Cumberland

Ridge

and

Valley 0

16

2

4

6

8

10

12

14

TOTAL NITROGEN INPUTS, IN TONS PER SQUARE MILE

EXPLANATION

ANIMAL WASTE

FERTILIZER

NITROGEN FIXATION

ATMOSPHERIC DEPOSITION

Plain

Coastal Transition

Rim

Highland

Western

Basin

Nashville

Outer

Basin

Nashville

Inner

Rim

Highland

Eastern

Valleys

and

Escarpment

Plateau Plateau Cumberland

Ridge

and

Valley 0

3.5

0.5

1.0

1.5

2.0

2.5

3.0

TOTAL PHOSPHORUS INPUTS, IN TONS PER SQUARE MILE

EXPLANATION

ANIMAL WASTE

FERTILIZER

Figure 22. Estimated unit area total nitrogen and phosphorus inputs from nonpoint

sources by subunit in the lower Tennessee River Basin, 1992 (U.S. Department of

Commerce, 1994).

NITROGEN

PHOSPHORUS

SUBUNIT

input from nonpoint sources (fig. 22) because inputs 

from other sources are relatively low. Nitrogen fixation 

contributed the smallest amount of nitrogen in all 

subunits, but accounted for as much as about 16 percent of the nitrogen input in the Coastal Plain.

Inputs of phosphorus from livestock waste also 

were larger on a per unit area basis than inputs from 

fertilizer application for each subunit except the Eastern Highland Rim and Coastal Plain, where phosphorus input from fertilizer application was about the 

same or slightly more than from animal waste 

(fig. 22). About 23,500 tons of phosphorus were contributed by livestock waste and 14,500 tons of phosphorus by fertilizer application to the study unit in 

1992 (table 4). 

Pesticide Use

Pesticide use has increased tenfold since 1975, 

with 75 percent of the pesticide use related to agricultural production (Ware, 1989). Pesticides have become 

an important crop management tool for controlling 

insects, weeds, fungi, and bacteria, and their use has 

significantly increased crop production. Despite the 

increases in agricultural productivity and the associated economic benefits, a general concern exists about 

dispersing large quantities of these substances, which 

are designed to be toxic, into the environment. 

The fate of pesticides in the environment is 

influenced by the method of application, physical and 

chemical properties of each pesticide, and many environmental factors. Pesticides are designed to degrade 

Figure 22. Estimated unit area total nitrogen and phosphorus inputs from nonpoint 

sources by subunit in the lower Tennessee River Basin, 1992. (U.S. Department of 

Commerce, 1994.)
32 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

in a few days or weeks after application under ideal 

conditions. Movement of pesticides into ground-water 

or surface-water systems may reduce the rate at which 

pesticides degrade. Degradation products of pesticides 

can behave quite differently than parent compounds 

and may be more persistent or mobile in the environment.

Use of pesticides (herbicides, insecticides, and 

other pesticides) was estimated for each subunit to 

identify the primary compounds used, and the areal 

distribution of use in the lower Tennessee River Basin. 

For the purpose of this report, organic compounds 

used in crop production such as growth inhibitors and 

defoliants, are referred to as other pesticides. Estimates of pesticide use are based on reported harvested 

acreage of crops (U.S. Department of Commerce, 

1994) and statewide application rates for a given compound (Gianessi and Anderson, 1995). These estimates, therefore, do not account for municipal and 

private use of pesticides or where local farming practices differ from general practices in the State.

About 3.7 million pounds of pesticides (active 

ingredient) was used in the lower Tennessee River 

Basin in 1992. Herbicides accounted for about twothirds of total pesticide use (table 5). Eleven herbicides 

were used in amounts exceeding 100,000 pounds 

(table 5). Atrazine, a herbicide used primarily for corn 

production, was used in the largest amounts; followed 

by monosodium methanearsonate (MSMA), used primarily on cotton; 2,4-D used on corn and pasture land; 

and metalochlor used on corn and soybeans. Insecticide use in 1992 totalled about 0.9 million pounds 

(table 5) and accounted for about a quarter of the total 

pesticide use. Methyl parathion was used in the largest 

amounts, and was primarily applied to cotton. Thiodicarb, 1,3 dichloropropene, and aldicarb followed 

methyl parathion in amount used in 1992 and also 

were used primarily on cotton. Compounds termed 

other pesticides in table 5 include plant growth regulators (mancozeb and ethephon), defoliants (tribufos), 

fumigants (methyl bromide), and fungicides (sulfur). 

Methyl bromide was used in the largest amounts, primarily as a soil fumigant for tomato and tobacco cultivation. Tribufos and ethephon were used primarily on 

cotton and followed methyl bromide in 1992 estimated 

use (table 5).

Almost half of the total pesticides used in 1992 

were applied to cropland in the Eastern Highland Rim, 

which had the largest unit-area pesticide use of all subunits, about 540 lb/mi2

 (table 5). Insecticide use in the 

Eastern Highland Rim represented 69 percent of the 

total insecticide use for the study unit and herbicide 

use there represented about 40 percent of the total. The 

majority of the insecticide used in the study unit was 

for cotton, which was primarily grown in the Eastern 

Highland Rim. Estimates of unit-area pesticide use for 

the Coastal Plain and Inner Nashville Basin were 

ranked second and third among the subunits; these 

ranks generally correlate with the relative percentage 

of cultivated land in each subunit (table 2).

WATER-QUALITY ISSUES

Increases in population, water use, and urban 

and agricultural land development affect the quality of 

surface- and ground-water resources in parts of the 

lower Tennessee River Basin. State water-quality 

agencies have identified 109 stream segments and 3 

lakes in the study unit that are water-quality impaired 

with respect to their designated use (Alabama Department of Environmental Management, 1996; Georgia 

Department of Natural Resources, 1996; Kentucky 

Natural Resources and Environmental Protection Cabinet, 1996; Mississippi Department of Environmental 

Quality, 1996; Tennessee Department of Environment 

and Conservation, 1996). The primary nonpoint 

sources affecting surface-water quality cited by these 

agencies were agricultural and urban runoff. In order 

of frequency of citation, the predominant causes of 

impairment resulting from nonpoint sources were siltation, organic enrichment and dissolved-oxygen 

depletion, nutrient enrichment, and pathogens. The 

primary point sources affecting surface-water quality 

cited by these agencies were industrial and municipal 

discharges. In order of frequency of citation, causes 

for impairment from point sources were pathogens, 

organic enrichment and dissolved-oxygen depletion, 

ammonia, and siltation.

These State agencies also have documented 

contamination of ground water from both nonpoint 

and point sources. Ground-water studies conducted in 

the study unit have documented shallow ground-water 

contamination by pesticides, nutrients, and bacteria 

from nonpoint sources (Alabama Department of Environmental Management, 1996; Tennessee Department 

of Environment and Conservation, 1996). Carbonate 

rock aquifers are common in the study unit and have a 

high potential to be affected by nonpoint sources. 

Point sources affecting ground-water quality included 

underground storage tanks, landfills, and contamination from industrial sites. Volatile organic compounds 
Water-Quality Issues 33

were the constituents most often associated with pointsource contamination of ground-water aquifers.

The changes in water quality as a result of contamination from these sources can affect both human 

health and the health of aquatic ecosystems. Excessive 

nitrate concentrations (greater than 10 mg/L as N) in 

untreated, domestic drinking water can pose a health 

risk to infants by causing methemoglobinemia, or blue 

baby syndrome. Nutrient enrichment in surface-water 

bodies may produce algal blooms that cause taste and 

odor problems in drinking water. Excessive growth of 

algae and aquatic macrophytes also can deplete dissolved oxygen in streams and reservoirs, adversely 

affecting fish and other aquatic life. Degradation of 

water quality and destruction of instream and riparian 

habitat threatens freshwater mussels and fish in 

streams in the study unit. For example, the Muscle 

Shoals area, near Florence, Alabama, once had one of 

the most diverse assemblages of mussels in the world. 

Many species have become extinct and several of the 

remaining species are now endangered or threatened. 

Pesticides and other organics can be toxic to aquatic 

invertebrates and fish or may accumulate in fish tissue 

and sediment. Six fish consumption advisories have 

been issued for streams and reservoirs in the study 

unit. These advisories include DDT in fish in Indian 

Creek, polychlorinated biphenols (PCB’s) in fish in 

Woods Reservoir and Nickajack Lake, and chlordane 

in fish in Nickajack Lake (Alabama Department of 

Environmental Management, 1996; Tennessee Department of Environment and Conservation, 1996 ).

Selected Water-Quality Data

Data for nutrients and bacteria in surface and 

ground water collected between 1980 and 1996 and 

available in digital format were summarized by subunit to characterize the water quality of the subunits 

for constituents that represent major water-quality 

issues in the study unit. Nutrients and bacteria were 

selected because these constituents were cited as 

affecting both surface- and ground-water quality. The 

U.S. Environmental Protection Agency’s STOrage and 

RETrieval (STORET) data base and the U.S. Geological Survey water-quality data base WATer STOrage 

and REtrieval system (WATSTORE) were the primary 

sources for both surface- and ground-water-quality 

data. Additional data from local ground-water studies 

conducted by State agencies were included in the data 

set. Data retrieved from STORET and WATSTORE 

were screened to select ambient data. Median values 

were used in this data summary for sites with multiple 

samples. Data likely to be affected by point sources 

were excluded from the data set. Only surface-waterquality sites with drainage areas contained within a 

single subunit were included in this data summary. 

Ground-water-quality data were limited to sites that 

represented the shallow ground-water flow system. In 

most of the subunits, wells with depths less than 300 ft 

were selected, but in the Coastal Plain and Transition, 

wells less than 200 ft deep were selected.

Data from STORET and WATSTORE were 

combined to improve the spatial distribution of sites in 

each subunit. Combining the data bases resulted in a 

total of about 520 surface-water sites with waterquality data for at least one of the nutrients (nitrogen 

and phosphorus) and about 360 surface-water sites 

with data for fecal coliform occurrence. The distribution of surface-water sites was similar for STORET 

and WATSTORE, though the total number of sites was 

considerably higher in STORET (fig. 23). Most subunits had 40 or more surface-water sites with data for 

nutrients and 30 or more sites with data for fecal 

coliform. The Eastern Highland Rim had the most 

surface-water-quality sites. The Inner Nashville Basin 

and the Valley and Ridge, the smallest subunits, had 

the fewest number of sites with data for both nutrients 

and bacteria.

Ground-water data from the two data bases were 

unevenly distributed across the study unit (fig. 23). 

Combining data from STORET and WATSTORE and 

the local ground-water studies yielded about 1,240 

wells and springs with data for at least one nutrient. 

Much of the available ground-water data for nutrients 

were collected in the Eastern Highland Rim as part of 

a study by the Alabama Department of Environmental 

Management, in which about 400 shallow wells 

located in agricultural areas in four counties in northern Alabama were sampled twice for nitrate and four 

pesticides (E. Bittner, Alabama Department of Environmental Management, written commun., 1997). 

About 490 ground-water sites had data for fecal 

coliform. 

Nutrients in Surface and Ground Water

Nutrient enrichment was cited as the cause of 

impairment for 37 of the 109 impaired stream segments and was identified as an important issue for 

ground-water quality in the lower Tennessee River 

Basin (Alabama Department of Environmental Management, 1996; Georgia Department of Natural 
3

4EnvironmentalSettingandWater-QualityIssuesinthe

LowerTennesseeRiverBasin

Table 5. Estimated use of selected pesticides by subunit in the lower Tennessee River Basin, 1992[Values in pounds of active ingredient applied rounded to the nearest hundred pound. Estimated use calculated using application rates from Gianessi and Anderson, 1Agricultural Census, U.S. Department of Commerce, 1994]

Western Outer Inner Eastern Plateau and

Coastal Highland Nashville Nashville Highland Escarpment Cumberla

Plain Transition Rim Basin Basin Rim Valleys Plateau 

Herbicides

2,4-D 22,500 26,000 39,500 26,800 9,900 85,900 20,800 43,100 Acifluorfen 3,000 3,300 1,600 1,000 600 8,100 1,900 2,100 Alachlor 37,300 6,900 22,000 9,800 6,600 36,800 8,100 8,500 Atrazine 125,300 13,600 84,100 33,500 24,000 101,300 24,200 31,700 Bentazon 4,500 2,300 2,100 1,500 800 7,800 1,800 1,800 Butylate 50,900 3,500 23,600 7,100 5,100 23,600 6,100 8,600 Cyanazine 17,400 6,300 18,300 18,300 3,300 58,100 1,400 1,600 DSMA 500 3,900 7,300 900 <100 48,100 100 1,300 Fluometuron 3,600 10,400 17,400 2,700 <100 105,600 400 2,900 Glyphosate 32,700 4,900 14,400 7,500 4,300 27,900 4,800 5,100 Metolachlor 75,700 7,200 34,900 14,700 9,600 37,100 7,600 6,700 MSMA 3,000 18,600 37,300 4,600 <100 242,400 800 6,700 Norflurazon 300 4,800 9,900 1,100 <100 65,800 200 1,800 Paraquat 8,000 1,900 4,900 2,100 1,200 11,400 1,200 1,100 Pendimethalin 11,400 10,700 12,100 3,900 1,500 66,200 5,000 6,800 Simazine 20,000 700 14,200 6,100 4,500 12,000 1,900 900 Trifluralin 15,900 11,400 14,300 4,100 1,500 78,100 7,200 9,500 Total herbicide use 432,000 136,400 357,900 145,700 72,900 1,016,200 93,500 140,200 

Insecticides

1,3 Dichloropropene <100 3,500 9,000 4,400 <100 64,700 200 1,700 Acephate 5,800 4,200 7,800 2,800 1,000 37,800 800 1,800 Aldicarb 1,700 4,700 9,600 1,400 <100 58,700 200 1,600 Carbaryl 2,500 1,400 1,500 800 500 3,300 2,200 1,500 Carbofuran 5,900 1,600 4,500 1,600 1,000 10,200 3,500 6,300 Chlorpyrifos 10,100 1,300 9,700 4,600 3,100 13,100 1,200 800 Dicrotophos 1,100 1,800 3,300 600 <100 18,700 100 500 Disulfoton 700 2,200 4,900 700 <100 30,500 200 900 Ethyl parathion <100 300 400 0 <100 2,300 900 1,900 Malathion 1,200 3,800 7,500 1,100 300 48,400 200 1,400 
Water-Quality Issues 35

Table 5. Estimated use of selected pesticides by subunit in the lower Tennessee River Basin, 1992—Continued

Western Outer Inner Eastern Plateau and

Coastal Highland Nashville Nashville Highland Escarpment Cumberla

Plain Transition Rim Basin Basin Rim Valleys Plateau 

Insecticides—Continued

Methyl parathion 1,700 17,000 20,100 2,300 100 134,300 1,300 5,400 PCNB 1,000 4,500 7,800 1,000 <100 49,300 200 1,400 Profenofos 600 5,700 7,200 800 <100 47,900 100 1,300 Thiodicarb 700 5,900 11,700 1,400 <100 77,300 300 2,200 Total insecticide use 33,000 57,900 105,000 23,500 6,000 596,500 11,400 28,700 

Other Pesticides

Chloropicrin 1,400 <100 1,200 1,100 500 900 3,600 700 Ethephon 1,300 5,100 9,700 1,600 200 60,600 200 1,700 Mancozeb 4,200 800 2,600 1,700 1,000 5,400 5,300 10,800 Methyl Bromide 13,500 3,000 12,300 11,000 5,100 14,200 24,000 33,000 Sodium chlorate 300 5,200 8,300 900 <100 55,700 200 1,600 Sulfur 1,300 1,800 1,200 1,300 100 26,200 3,600 5,900 Tribufos 1,100 7,100 11,600 1,400 <100 75,000 200 2,100 Total other

pesticide use 23,100 23,000 46,900 19,000 6,900 238,000 37,100 55,800 

Total pesticide

 use 488,100 217,300 509,800 188,200 85,800 1,850,700 142,000 224,700 

Total pesticide use 

per square mile 204 127 99 90 151 541 75 103 
36 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

88

87

86

o

o

o

36o

35o

Duck

River

Elk

River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock

Ri v er

Beech River

Sequatchie River

River

Kentucky

Lake

Wheeler

Wilson

Lake

Pickwick

L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big

Sandy River

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Base from U.S. Geological Survey,

1:2,000,000 digital line graph

Town

Creek

EXPLANATION

SURFACE-WATER-QUALITY SITES

 IN STORET

U.S. GEOLOGICAL SURVEY SURFACEKENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

 WATER-QUALITY SITES

Figure 23. Location of (A) surface-water quality sites and (B) ground-water quality sites that have data

for nutrients in STORET or WATSTORE, 1980-96.

A.

Lake

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Subunits modified from King and Beikman, 1974; Smalley, 1983;

Osborne and others, 1989; and Griffith and others, 1997

Figure 23. Location of (A) surface-water-quality sites and (B) ground-water-quality sites that have data for nutrients in STORET or 

WATSTORE, 1980-96. 
Water-Quality Issues 37

88

87

86

o

o

o

36o

35o

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

1:2,000,000 digital line graph

EXPLANATION

Base from U.S. Geological Survey,

KENTUCKY

TENNESSEE

TENNESSEE

ALABAMA

MISSISSIPPI

GEORGIA

GROUND-WATER-QUALITY SITE IN STORET OR ALABAMA DEPARTMENT

 OF ENVIRONMENTAL MANAGEMENT GROUND-WATER-QUALITY SITE

U.S. GEOLOGICAL SURVEY GROUND-WATER-QUALITY SITE

B.

Figure 23. Location of (A) surface-water quality sites and (B) ground-water quality sites that have data

for nutrients in STORET or WATSTORE, 1980-96 Continued.

Transition

subunit

Western

Highland

Rim subunit

Coastal

Plain

subunit

Outer

Nashville

Basin subunit

Inner

Nashville

Basin subunit

Valley

and

Ridge

subunit

Eastern

Highland

Rim subunit

Plateau

Escarpment

and

Valleys

subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Cumberland

Plateau subunit

Figure 23. Location of (A) surface-water-quality sites and (B) ground-water-quality sites that have data for nutrients in STORET or 

WATSTORE, 1980-96—Continued. 
38 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Resources, 1996; Kentucky Natural Resources and 

Environmental Protection Cabinet, 1996; Mississippi 

Department of Environmental Quality, 1996; Tennessee Department of Environment and Conservation, 

1996). Nutrients were the most commonly analyzed 

water-quality constituents in surface and ground water 

in the lower Tennessee River Basin during 1980-96. 

Nitrogen can be found in surface and ground water in 

several oxidation states. In its reduced valence states, 

nitrogen is found primarily as ammonia, ammonium, 

and organic compounds; in its oxidized valence state, 

nitrogen is found primarily as nitrate and nitrite. Phosphorus also can occur in several oxidation states, but in 

natural waters the fully oxidized species (phosphate) is 

most common, but phosphorus also can be found in 

organic compounds. Phosphorus in its oxidized state 

has a low solubility and is often associated with sediment or other particulate material. 

Given the various forms that nitrogen and phosphorus can be found in natural waters and the fact that 

data were collected for different objectives, available 

nutrient data were stored under a mix of different 

parameter codes. To obtain adequate spatial coverage 

across the study unit, data stored with different nutrient parameter codes were combined. For example, 

data for nitrate and nitrite were commonly reported as 

nitrite-plus-nitrate, nitrite, or nitrate in both dissolved 

(filtered) or total concentrations (unfiltered). Generally, nitrite concentrations are small compared to those 

of nitrate in oxic waters (including shallow ground 

water), and the concentrations of nitrite and nitrate 

associated with sediment and particulate material also 

are small. Therefore, nitrite-plus-nitrate and nitrate, 

filtered and unfiltered, were combined as an estimate 

of nitrate-nitrogen, when data for only one of these 

constituents were available. Ammonia and organic 

nitrogen were summed as an alternate to total Kjeldahl 

nitrogen (total ammonia and organic nitrogen) where 

total Kjeldahl nitrogen was not reported. If more than 

one minimum reporting level was present in the data, 

the highest minimum reporting level was applied to all 

of the data.

Nitrate-nitrogen was the most commonly 

reported nutrient species in both surface- and groundwater samples between 1980 and 1996. Median concentrations of nitrate in surface water in each subunit 

were less than 1 mg/L (fig. 24). Median concentrations 

(0.6 to 0.8 mg/L) were higher in the Outer and Inner 

Nashville Basins, Eastern Highland Rim, and Cumberland Plateau, than in the remaining subunits (less than 

0.3 mg/L). Median concentrations of nitrate in ground 

water in most subunits were less than 1 mg/L, but were 

greater than 1 mg/L in samples collected in the Eastern 

Highland Rim and the Cumberland Plateau (fig. 24). 

The ninetieth percentile concentration in the Cumberland Plateau exceeded the recommended drinking 

water maximum contaminant level of 10 mg/L (U.S. 

Environmental Protection Agency, 1995). Median 

nitrate concentrations were higher in ground water 

than surface water in most subunits (fig. 24). In both 

the Outer and Inner Nashville Basins, however, 

median concentrations were higher in surface water. In 

all subunits, concentrations at the ninetieth percentile 

were higher in ground water than in surface water.

Median concentrations of total Kjeldahl nitrogen were generally less than 0.5 mg/L in each subunit 

(fig. 24), except those in the Inner Nashville Basin, 

Valley and Ridge, and Cumberland Plateau which 

exceeded 1 mg/L. Ground-water data for total 

Kjeldahl nitrogen were not available in many of the 

subunits, and data were insufficient in the remaining 

subunits to make a meaningful comparison. Concentrations for total Kjeldahl nitrogen in ground water, 

where available, were less than 1 mg/L.

Nutrient concentrations in surface and ground 

water were compared to the density of agricultural 

land use in each subunit. The rank of median concentrations by subunit for nitrate and total Kjeldahl nitrogen (fig. 24) in surface water roughly correlates with 

the percentage of agricultural land use in each subunit 

(table 2) and estimates of total nitrogen input from 

nonpoint sources (fig. 22). Concentrations of nitrogen 

in surface-water samples are highest in the Outer and 

Inner Nashville Basins, Eastern Highland Rim, and the 

Cumberland Plateau. Agricultural land use was also 

greatest for these subunits. However, the Coastal Plain, 

which had total nitrogen inputs comparable to the 

Outer Nashville Basin (fig. 22), has small nitrogen 

concentrations relative to the other subunits (fig. 24). 

The lower than expected nitrogen concentrations in 

samples collected from streams in the Coastal Plain 

may be a result of the type of nitrogen input and 

hydrogeology of the subunit. The nitrogen input from 

livestock waste is much lower in the Coastal Plain than 

in the other four subunits with comparable total nitrogen input (fig. 22). No relation could be identified 

between nitrogen concentrations in ground water and 

land use in a subunit. Agricultural land use was highest in the Inner Nashville Basin, but nitrate concentrations in ground water were lowest in this subunit.
Water-Quality Issues 39

10

0.1

0.01

0.1

1

10

 

 1

45

20 38

75

5 76

33

49 5

91

40 25

35

76

 5

82

26

43

3

TOTAL PHOSPHORUS AS P, IN

MILLIGRAMS PER LITER

TOTAL KJELDAHL NITROGEN AS

N, IN MILLIGRAMS PER LITER

Surface water

Surface water

Coastal

Plain

TransitionWestern

Highland

Rim

Outer

Nashville

Basin

Inner

Nashville

Basin

Eastern

Highland

Rim

Plateau

Escarpment

and

Valleys

Cumberland

Plateau

Valley

and

Ridge

SUBUNIT

Figure 24. Concentrations of selected nutrients in surface and ground

water by subunit in the lower Tennessee River Basin, 1980-96.

0.1

1

10

100

5 8

55

38

80 100

39 27 48

100

10

1

0.1

12 47

147 145

163

575

58

91

NITRATE AS N, IN MILLIGRAMS PER LITER

Surface water

Ground water

EXPLANATION

NUMBER OF SITES

PERCENTILE OF CUMU-

 LATIVE FREQUENCY

 DISTRIBUTION OF SITE

 MEDIAN VALUES

DATA POINT

90th

75th

50th

25th

10th

Figure 24. Concentrations of selected nutrients in surface and ground water by subunit in the lower 

Tennessee River Basin, 1980-96.
40 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

COLONIES PER 100 MILLILITERS

100,000

10,000

1,000

100

10

1

(92)

60

(21)

35 (40)

30

(49)

64

(163)

12

(170)

57

(65)

63 (55)

34

 3

(40)

26

(49)

55

(163)

69

(170)

224

(65)

17

10

100

1,000

10,000

100,000

1

(55)

80

Surface water

Ground water

Coastal

Plain

TransitionWestern

Highland

Rim

Outer

Nashville

Basin

Inner

Nashville

Basin

Eastern

Highland

Rim

Plateau

Escarpment

and

Valleys

Cumberland

Plateau

Valley

and

Ridge

SUBUNIT

Figure 25. Counts of fecal coliform in surface and ground water by

subunit in the lower Tennessee River Basin, 1980-96.

(40)

26

EXPLANATION

NUMBER OF SITES (NUMBER IN

 PARENTHESES IS POPULATION

 PER SQUARE MILE)

PERCENTILE OF CUMULATIVE

 FREQUENCY DISTRIBUTION

 OF SITE MEDIAN VALUES

DATA POINT

90th

75th

50th

25th

10th

(206)

(92) (21) (206)

Natural setting is likely as important to concentrations of total phosphorus as the distribution of 

inputs of phosphorus in the lower Tennessee River 

Basin. Total-phosphorus data were available for about 

350 surface-water sites and fewer than 70 groundwater sites in the nine subunits. Median concentrations 

of total phosphorus for surface-water sites were highest (about 0.3 mg/L) in the Inner and Outer Nashville 

Basins; median total phosphorus concentrations were 

about 0.1 mg/L or less in the remaining subunits 

(fig. 24). Phosphatic limestones present in the Inner 

and Outer Nashville Basin likely contribute to the elevated phosphorus concentrations there. This natural 

source also would account for the relatively high concentrations of phosphorus in streams in these subunits 

compared to other subunits with similar phosphorus 

inputs (fig. 22). Total-phosphorus data for ground 

water were limited, and only two subunits were represented by more than four sites. Total-phosphorus concentrations in ground water generally were less than 

0.1 mg/L for most sites. No relation was evident 

between total-phosphorus concentrations in surface or 

used in water-quality assessments, data for fecal 

coliform were the most frequently reported in both 

STORET and WATSTORE for the period 1980-96 and 

are summarized in this report.

Median counts of fecal coliform were higher in 

surface water than in ground water for each subunit 

(fig. 25). The highest median counts in surface water 

were about 7,500 colonies per 100 milliliters 

(col./100 mL) in the Valley and Ridge and about 

5,000 col./100mL in the Outer Nashville Basin; however, data were reported for only three sites in the 

Valley and Ridge. The typical range in counts of fecal 

coliform in surface water is less than 1 to 

5,000 col./100 mL and between 200 to greater than 

2,000,000 col./100 mL in fecal-contaminated surface 

water (Wilde and others, 1997). The criteria for protection of recreational water bodies in Tennessee is 

1,000 col./100 mL in a single sample (U.S. Environmental Protection Agency, 1999). Median reported 

fecal coliform counts for the Inner and Outer Nashville Basin and Valley and Ridge were greater than 

ground water and land use or nonpoint 

phosphorus inputs. 

Bacteria in Surface and Ground 

Water

Pathogens were cited as the 

cause of impairment for 29 of the 109 

impaired stream segments and also 

were identified as an issue for groundwater quality in the lower Tennessee 

River Basin by State water-quality 

agencies (Alabama Department of 

Environmental Management, 1996; 

Georgia Department of Natural 

Resources, 1996; Kentucky Natural 

Resources and Environmental Protection Cabinet, 1996; Mississippi 

Department of Environmental Quality, 

1996; Tennessee Department of Environment and Conservation, 1996). 

Fecal coliform bacteria are used to 

identify contamination to water bodies 

by waste from warm-blooded animals. 

Fecal coliform bacteria generally are 

not disease-causing, but their detection can indicate the presence of other 

more dangerous pathogens. Of the 

fecal-indicator bacteria commonly 

Figure 25. Counts of fecal coliform in surface and ground water by subunit 

in the lower Tennessee River Basin, 1980-96.
Summary 41

1,000 col./100 mL, suggesting that fecal contamination of surface water in these subunits is somewhat 

higher than in the remaining subunits. Median concentrations of fecal coliform in ground water were well 

below 200 col./100 mL in all subunits; however, no 

data were available for the Valley and Ridge. Median 

fecal coliform counts were highest for the Outer and 

Inner Nashville Basins and were lowest (less than 

1 col./100 mL) for both the Coastal Plain and Transition; however, the number of sites with data from these 

subunits was very low.

Natural setting is an important factor affecting 

fecal-contamination of surface and ground water in the 

study unit. Fecal coliform counts in both surface and 

ground water generally were highest in subunits 

underlain by carbonate rocks, and especially the 

Ordovician carbonate rocks that have thin to absent 

regolith overlying bedrock. Sources of fecal contamination cited by State water-quality agencies include 

sanitary and combined sewer overflows, leaking septic 

systems, and livestock waste. The correlation of fecal 

counts with the distribution of these sources is not a 

straightforward analysis, because data are not available to estimate the distribution and magnitude of 

sewer overflows and leaking septic systems. Population and livestock densities were used as indicators of 

potential sources within each subunit and were compared to the rank order of fecal coliform counts 

(fig. 25). In general, higher median fecal coliform 

counts were related to a greater population and livestock density (figs. 20 and 25). Exceptions to this relation were the Outer Nashville Basin, which ranked 

sixth in both population and livestock density but 

ranked first in median fecal coliform counts; and the 

Cumberland Plateau ranked relatively low in fecal 

coliform counts in surface water but was ranked highest in livestock density. Fecal coliform counts in 

ground water from the Outer Nashville Basin also 

ranked high compared to the relative density of population and livestock. 

SUMMARY

The lower Tennessee River Basin is one of 59 

National Water-Quality Assessment study units in 

which water-quality assessments have been or are 

being conducted by the U.S. Geological Survey. The 

lower Tennessee River Basin study unit encompasses 

about 19,500 mi2

 and extends from Chattanooga, Tennessee, to Paducah, Kentucky. Geology and physiography were used to subdivide the study unit into nine 

subunits that represent areas of relative geologic and 

physiographic homogeneity. This subdivision provides 

framework in which natural variability in water quality 

can be quantified and the effects of human-related factors on water quality can be assessed. The boundaries 

for these subunits are similar to the ecoregion boundaries. The nine subunits delineated in order of size are 

the Western Highland Rim, Eastern Highland Rim, 

Coastal Plain, Outer Nashville Basin, Plateau Escarpment and Valleys, Cumberland Plateau, Transition, 

Inner Nashville Basin, and Valley and Ridge. 

Much of the lower Tennessee River Basin is 

underlain by carbonate rocks, with smaller areas of 

unconsolidated sediments and siliciclastic rocks 

present in the western and eastern parts of the study 

unit, respectively. Most of the rock units in the study 

unit are undeformed and relatively flat-lying to gently 

dipping. Karst landforms, such as sinkholes, caves, 

and disappearing streams, are present in parts of the 

study unit underlain by carbonate rocks. Generally, the 

soils overlying bedrock in the study unit have moderate to slow infiltration rates.

The lower Tennessee River Basin lies within 

parts of the Coastal Plain, Interior Low Plateaus, and 

Appalachian Plateaus Physiographic Provinces. Relief 

is low to moderate in much of the study unit; high 

relief occurs between the Highland Rim and Cumberland Plateau Physiographic Sections of the Interior 

Low Plateaus and Appalachian Plateaus, respectively. 

Land-surface altitudes generally increase from about 

500 ft above sea level in the west to more than 2,000 ft 

above sea level in the east.

The main stem of the Tennessee River is highly 

regulated with few free-flowing stream reaches. Six 

reservoirs are located on the main stem and many 

additional reservoirs are located on tributaries to the 

main stem. Mean-annual streamflow in the Tennessee 

River increases from about 35,900 to about 

65,600 ft3/s from Chattanooga, Tennessee, to Paducah, 

Kentucky. The Elk and Duck Rivers are the two largest 

tributaries and contribute about 26 percent of the 

streamflow gained in the study unit. 

The Cretaceous sand, Pennsylvanian sandstone, 

Mississippian carbonate, and Ordovician carbonate 

aquifers account for most of the shallow ground-water 

flow in the study unit. Ground-water flow paths typically are short in these aquifers, and much of the 

recharge to the aquifers is discharged within the study 

unit. The shallow ground-water system generally is 

within 300 ft of land surface and flow is through 
42 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

unconsolidated sediments, solution openings in bedding planes and joints in bedrock, and in fractured 

bedrock. The Mississippian carbonate aquifer is the 

most productive in the study unit and is characterized 

by flow in solution openings. Estimates of the contribution of ground-water discharge to streamflow from 

the principal aquifers indicate that at least 50 percent 

of streamflow is contributed by ground-water 

discharge to streams.

Surface water is the principal source of water for 

both industrial use and public supply, and accounts for 

about 70 percent of the water used for drinking water. 

Much of surface water used is withdrawn from the 

main stem of the Tennessee River. Ground-water use is 

highest in the Eastern Highland Rim, where Huntsville, Alabama, the largest city in the study unit, uses 

ground water for about 40 percent of the water supply. 

Point-source discharges were estimated for 1995. The 

estimated total nitrogen input from wastewater discharges in the study unit was about 13,430 tons and 

the estimated total phosphorus load was 770 tons. 

Land use in the study unit largely reflects the 

geomorphology of the basin and the distribution of 

people. Large forested areas are present in the Plateau 

Escarpment and Valleys, Transition, and Western 

Highland Rim where the topography has moderate to 

high relief. Forest land is the largest land use in the 

Coastal Plain, Cumberland Plateau, and Valley and 

Ridge as well. Pasture land is the dominant land use in 

the Inner and Outer Nashville Basin and the Eastern 

Highland Rim. Cultivated land constitutes 6 percent or 

less of the land use in all subunits except the Eastern 

Highland Rim, where about 16 percent of the land is 

cultivated. Urban and developed land is 1 percent or 

less of the land use in most subunits.

Cultural factors most likely to have a widespread effect on water quality in the lower Tennessee 

River Basin are related to animal and rowcrop agriculture. Corn, soybeans, cotton, and wheat were the 

primary crops grown in the study unit in 1992. The 

Eastern Highland Rim and Coastal Plain were the 

most intensively farmed subunits. Cotton acreage in 

the Eastern Highland Rim was the largest crop by 

subunit. About 42 million chickens, 0.9 million cattle, 

and 0.3 million hogs were produced in 1992. The 

number of chickens per square mile was highest in the 

Cumberland Plateau. Cattle production was most 

intense in the Inner and Outer Nashville Basin, and 

hogs were raised primarily in the Coastal Plain. 

Nutrient inputs from agricultural activities and 

atmospheric deposition (nonpoint sources) were estimated for 1992. The estimated total nitrogen input 

from these sources was about 195,000 tons, with about 

74 percent of the total contributed by fertilizer and 

livestock waste. On a per unit area basis, nitrogen 

inputs were highest in the Eastern Highland Rim. 

Nitrogen inputs from livestock waste were highest in 

the Cumberland Plateau, Inner and Outer Nashville 

Basin, and Valley and Ridge. Nitrogen inputs from fertilizer application were highest in the Eastern Highland Rim, Coastal Plain, and Inner Nashville Basin. 

About 14,500 tons of phosphorus were contributed to 

the study unit as fertilizer and 23,500 tons were produced by livestock in the study unit in 1992. On a per 

unit area basis, livestock waste was the larger source 

of phosphorus in most subunits. In the Eastern Highland Rim and Coastal Plain, fertilizer input was about 

the same or slightly more than inputs from livestock 

waste.

About 3.7 million pounds of pesticides (active 

ingredient) were applied to agricultural land in the 

study unit in 1992. The herbicides atrazine, monosodium methanearsonate (MSMA), 2,4-D, and metalochlor were used in the largest amount (more than 

200,000 lb of each). Insecticides were used to a lesser 

extent and were applied primarily on cotton grown in 

the Eastern Highland Rim. About half of the pesticides 

used were applied to crops in the Eastern Highland 

Rim where about 538 lb of pesticides per square mile 

were applied. 

Nutrient and fecal coliform data collected 

between 1980 and 1996 indicate that natural setting 

likely has as important an effect as cultural factors on 

surface- and ground-water quality in the lower Tennessee River Basin. These constituents represent waterquality issues for both surface and ground water in the 

lower Tennessee River Basin. Median nitrate concentrations were less than 1 mg/L for surface and ground 

water in all subunits except for the Eastern Highland 

Rim and Cumberland Plateau, where the nitrate concentration at the ninetieth percentile exceeded the 

maximum contaminant level for drinking water for 

nitrate (10 mg/L). In general, median concentrations 

of nitrogen species were highest in subunits where percentages of agricultural land use were highest. Median 

phosphorus concentrations in surface water were less 

than 1 mg/L in all subunits. The Inner and Outer Nashville Basin had the highest concentrations, probably a 

result of naturally occurring sources of phosphorus in 
References 43

phosphatic limestones in the Ordovician carbonate 

rocks. Available data for phosphorus concentrations in 

ground water were limited, but concentrations were 

generally less than 1 mg/L. Median counts of fecal 

coliform were higher in surface water than ground 

water. The highest median counts in surface water 

were in the Valley and Ridge (7,500 col./100 mL) and 

the Outer Nashville Basin (5,000 col./100 mL). Highest median counts in ground water were in the Inner 

and Outer Nashville Basin. 

REFERENCES

Alabama Department of Environmental Management, 1986, 

Water quality report to Congress: Montgomery, Alabama, variously paginated.

Bailey, R.G., Avers, P.E., King, T., and McNab, W.H., eds., 

1994, Ecoregions and subregions of the United States 

(map) (supplementary table of map unit descriptions 

compiled and edited by McNab, W.H., and Bailey, 

R.G.): Washington, D.C., U.S. Department of 

Agriculture-Forest Service, scale 1:1,750,000.

Battaglin, W.A., and Goolsby, D.A., 1995, Spatial data in 

geographic information system format on agricultural 

chemical use, land use, and cropping practices in the 

United States: U.S. Geological Survey WaterResources Investigations Report 94-4176, 87 p.

Brahana, J.V., and Bradley, M.W., 1986, Preliminary delineation and description of the regional aquifers of Tennessee—The Highland Rim aquifer system: U.S. 

Geological Survey Water-Resources Investigations 

Report 82-4054, 38 p.

Brahana, J.V., Macy, J.A., Mulderink, Dolores, and Zemo, 

Dawn, 1986a, Preliminary delineation and description 

of the regional aquifers of Tennessee—Cumberland 

Plateau aquifer system: U.S. Geological Survey WaterResources Investigations Report 82-338, 24 p.

Brahana, J.V., Mulderink, Dolores, and Bradley, M.W., 

1986b, Preliminary delineation and description of the 

regional aquifers of Tennessee—The Cretaceous aquifer system of west Tennessee: U.S. Geological Survey 

Water-Resources Investigations Report 83-4039, 20 p.

Craig, N., and Kuenzler, E.J., 1983, Land use, nutrient 

yield, and eutrophication in the Chowan River Basin: 

Raleigh, North Carolina, The University of North 

Carolina Research Institute, Report No. 205.

Daniel, J.F., 1976, Estimating groundwater evapotranspiration from streamflow records: Water Resources 

Research, v. 12, no. 3, p. 360-364.

Fenneman, N.M., 1938, Physiography of Eastern United 

States: New York, McGraw-Hill, 714 p.

Gaydos, M.W. and others, 1982, Hydrology of area 17, eastern coal province, Tennessee and Kentucky: U.S. Geological Survey Water-Resources Investigations OpenFile Report 81-1118, 77 p. 

Gebert, W.A., Graczyk, D.J., and Krug, W.R., 1987, Average annual runoff in the United States, 1951-1980: 

U.S. Geological Survey Hydrologic Atlas, HA-710, 

scale 1:7,500,000. 

Georgia Department of Natural Resources, 1996, Water 

quality in Georgia 1994-1995: Environmental Protection Division, Atlanta, Georgia, variously paginated.

Gianessi, L.P., and Anderson, J.E., 1995, Pesticide use in 

U.S. crop production: National data report: Washington, D.C., National Center for Food and Agriculture 

Policy. 

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.

Harned, D.A., 1995, Effects of agricultural landmanagement practices on water quality in northeastern 

Guilford County, North Carolina, 1985-90: U.S. Geological Survey Water-Supply Paper 2435, 64 p.

Hoos, A.B., 1990, Recharge rates and aquifer hydraulic 

characteristics for selected drainage basins in Middle 

and East Tennessee: U.S. Geological Survey WaterResources Investigations Report 90-4015, 34 p.

Kentucky Natural Resources and Environmental Protection 

Cabinet, 1996, Kentucky report to Congress on water 

quality: Division of Water, Frankfort, Kentucky, variously paginated.

King, P.B., and Beikman, H.M., 1974, Geologic map of the 

United States: U.S. Geological Survey special map, 

3 sheets, scale 1:2,500,000.

McMaster, W.M., 1965a, Geology of the Elkmont quadrangle, Alabama-Tennessee: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-419, 

scale 1:24,000.

———1965b, Geology of the Salem quadrangle, AlabamaTennessee: U.S. Geological Survey Miscellaneous 

Geologic Investigations Map I-420, scale 1:24,000.

Miller, R.A., 1974, The geologic history of Tennessee: Tennessee Division of Geology Bulletin 74, 63 p.

Mississippi Department of Environmental Quality, 1996, 

State of Mississippi water quality assessment 1996: 

Jackson, Mississippi, Office of Pollution Control, 

165 p.

National Oceanic and Atmospheric Administration, 1993, 

The national coastal pollutant discharge inventory 

point source methods document: Silver Spring, Maryland, Pollution Sources Characterization Branch, variously paginated.

Omernik, J.M., 1987, Aquatic ecoregions of the conterminous United States: Annals of the Association of 

American Geographers, v. 77, p. 118-125.

Osborne, W.E., Szabo, M.W., Copeland, C.W., and Neathery, T.L., comps., 1989, Geologic map of Alabama: 

Geological Survey of Alabama Special Map 221, 

scale 1:500,000.

Rorabaugh, M.I., 1964, Estimating changes in bank storage 

and ground-water contribution to streamflow: International Association of Scientific Hydrology, Publication 

63, p. 432-441.
44 Environmental Setting and Water-Quality Issues in the 

Lower Tennessee River Basin

Rutledge, A.T., 1998, Computer programs for describing 

the recession of ground-water discharge and for estimating mean ground-water recharge and discharge 

from streamflow records—update: U.S. Geological 

Survey Water-Resources Investigations Report 98-4148, 

43 p.

Smalley, G.W., 1983, Classification and evaluation of forest 

sites on the Eastern Highland Rim and Pennyroyal: 

U.S. Forest Service Southern Forest Experiment Station General Technical Report SO-43, 123 p.

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

resources of Tennessee: Tennessee Division of Geology Bulletin 48, 444 p.

Tennessee Department of Environment and Conservation, 

1996, The status of water quality in Tennessee—The 

1996 305(b) report: Nashville, Tennessee, Division of 

Water Pollution Control, 99 p.

U.S. Department of Agriculture, 1994, State soil geographic 

(STATSGO) data base, data use information: Fort 

Worth, Texas, U.S. Department of Agriculture Miscellaneous Publication no. 1492, 88 p.

U.S. Department of Commerce, 1994, Census of Agriculture geographic area series 1B, U.S. summary and 

county level data: Washington, D.C., Bureau of 

Census.

———1995, Climatology of the United States: Monthly 

station normals for temperature, precipitation, and 

heating and cooling degree days, 1961-90, TD-9641: 

Asheville, North Carolina, National Climatological 

Data Center, (digital data set).

———1997, Population distribution and population estimates: U.S. Bureau of Census, accessed August 7, 

1997, at URL http://www.census.gov/population/www/estimates/countypop/html/

U.S. Environmental Protection Agency, 1995, Drinking 

water regulations and health advisories: Washington, 

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

Water, 11 p.

———1999, Bacterial water quality standards for recreational waters (fresh and marine waters) accessed 

April, 19, 1999, at http://www.epa.gov/OST/beaches/

local/sumtable.html/

U.S. Geological Survey, 1997, Aggregated water use data 

systems, data base—1995 water use data: Data on file 

at the U.S. Geological Survey, Water Resources Division, Nashville, Tennessee.

Ware, G.W., 1989, The pesticide book (3rd ed.): Fresno, 

California, Thomson Publications, 340 p. 

Wilde, F.D., Radtke, D.B., Gibs, J., and Iwatsubo, R.T., eds., 

1997, National field manual for the collection of waterquality data: U.S. Geological Survey Techniques of 

Water-Resources Investigations, Book 9, Chapter A7, 

38 p.

Zurawski, Ann, 1978, Summary appraisals of the Nation’s 

ground-water resources: U.S. Geological Survey 

Professional Paper 813-L, 35 p.