U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2008-5058

Prepared in cooperation with the Tennessee Duck River Agency 

Estimated Use of Water in the Upper Duck River 

Watershed, Central Tennessee, and Water-Demand 

Projections through 2030
Cover photograph. The Duck River in Tennessee. (Photograph by Rodney R. Knight.)
Estimated Use of Water in the Upper Duck River 

Watershed, Central Tennessee, and Water-Demand 

Projections through 2030

By Susan S. Hutson

Prepared in cooperation with the Tennessee Duck River Agency

Scientific Investigations Report 2008-5058

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation:

Hutson, S.S., 2008, Estimated use of water in the upper Duck River watershed, central Tennessee, and water-demand 

projections through 2030: U.S. Geological Survey Scientific Investigations Report 2008-5058, 16 p.
iii

Contents

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

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................1

Approach................................................................................................................................................2

Hydrologic Setting ................................................................................................................................2

Water Use .......................................................................................................................................................2

Estimated Water Demand.............................................................................................................................5

Modeling Scenarios .............................................................................................................................6

Water-Use Projections.......................................................................................................................10

Data Preparation/Model Input..........................................................................................................10

Projected Water Demand...........................................................................................................................12

Summary........................................................................................................................................................14

References ...................................................................................................................................................15

Glossary.........................................................................................................................................................16

Figures

1–2. Maps showing—

 1. Upper Duck River study area and the Maury-southern Williamson, 

Marshall, Bedford, and Coffee water-service areas.......................................................3

 2. Physiographic regions and major aquifers in the upper Duck River watershed........4

3. Graphs showing historic water withdrawals for Columbia Water System, 

Shelbyville Water System, Lewisburg Water System, Tullahoma Board of 

Utilities, Manchester Water System, and Bedford County Board of Utilities, 

Tennessee, 1981–2000..................................................................................................................6

4. Map showing location of the four National Oceanic and Atmospheric 

Administration cooperative weather observation sites in the 

upper Duck River watershed ......................................................................................................7

Tables

1. Surface-water and ground-water withdrawals by water-use category 

in the upper Duck River watershed, 2000 .................................................................................5

2. Total surface-water and ground-water withdrawals for municipal-supply use 

in 1981, 1985, 1990, 1995, and 2000 for the upper Duck River watershed study area ........5

3. Normal climatological conditions (based on climatological records from 

National Oceanic and Atmospheric Administration [NOAA] from 1971 to 2000) and 

mean monthly maximum air temperature and monthly rainfall for 1988, 2000, and 

2003 for Columbia and Tullahoma NOAA cooperative weather-observation sites............8

4. Water-supply systems and sources of supply in the 

upper Duck River watershed, 2000 and 2003 ...........................................................................9

5. Average per account use for selected water-supply systems in the upper Duck 

River watershed study area and billing account sectors for 2000 and 2003 ....................11

6. Average modeled household use for selected water-supply systems 

in the upper Duck River watershed study area for 2000 and 2003 .....................................12

7. Simulated water demand for the upper Duck River watershed study area 

for the Bedford, Coffee, Marshall, and Maury-southern Williamson 

water-service areas for 2000, 2010, 2020, and 2030 ..............................................................13
iv

Conversion Factors

Multiply By To obtain

Area

inch 2.54 centimeter (cm)

acre 4,047 square meter (m2

)

acre 0.004047 square kilometer (km2

)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

gallon (gal) 0.003785 cubic meter (m3

) 

million gallons (Mgal) 3,785 cubic meter (m3

)

cubic foot (ft3) 0.02832 cubic meter (m3) 

acre-foot (acre-ft) 1,233 cubic meter (m3

)

acre-foot (acre-ft) 0.001233 cubic hectometer (hm3

) 

Flow rate

acre-foot per year (acre-ft/yr) 0.001233 cubic hectometer per year (hm3

/yr)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

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

gallon per day (gal/d) 0.003785 cubic meter per day (m3

/d)

gallon per day per square mile 

[(gal/d)/mi2]

 0.001461 cubic meter per day per square

kilometer [(m3/d)/km2]

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3

/s)

million gallons per day per square mile 

[(Mgal/d)/mi2]

1,461 cubic meter per day per square

kilometer [(m3/d)/km2]

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

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

°F=(1.8×°C)+32

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

°C=(°F–32)/1.8

Horizontal coordinate information (lat/long) is referenced to the North American Datum of 1983 

(NAD 83). 

Elevation, as used in this report, refers to distance above the vertical datum.

Additional abbreviations used in this report

DP departure from normal precipitation

DRATAC Duck River Agency Technical Advisory Committee

DRWRC Duck River Water Resources Council

FY fiscal year

Gal/mo gallons per month

IWR-MAIN Institute for Water Resources–Municipal and Industrial Needs

MMMT mean monthly maximum air temperature

NOAA National Oceanic and Atmospheric Administration

TDRA Tennessee Duck River Agency

TVA Tennessee Valley Authority

USGS U.S. Geological Survey

WSA water-service area
Abstract

Future municipal water demand was estimated for the 

Bedford, Coffee, Marshall, and Maury-southern Williamson 

water-service areas in the upper Duck River watershed in 

central Tennessee through 2030. The Duck River, a primary 

source of municipal water, provided a total of 24.3 million 

gallons per day (Mgal/d) or 92 percent of the total water use 

in the study area during 2000. Municipal water use increased 

46 percent from 1981 to 2000 (from 18.0 to 26.3 Mgal/d). 

Water demand for municipal use is expected to continue to 

increase through 2030 because of the recent intensive and 

anticipated growth in the residential and commercial sectors.

Constant-rate models were used to estimate future municipal water demand. Data on residential and nonresidential 

billing accounts and estimates of public use and losses were 

used to calibrate the models. Two watershed scenarios for 

each water-supply system that depends on the Duck River for 

supply were simulated. Scenario 1 considered monthly water 

demand during typical weather conditions as represented by 

monthly per account use during 2003 and a rate of growth in 

customer accounts from 1999 to 2003. Results showed that 

total municipal water use could increase about 104 percent to 

51 Mgal/d by 2030, residential water use could increase about 

140 percent to 24 Mgal/d, nonresidential water use could 

increase about 110 percent to 17 Mgal/d, and public use and 

losses could increase about 83 percent to 11 Mgal/d.

Scenario 2 considered monthly water demand during 

drought conditions as represented by monthly per account use 

during 2000 and recent growth in customer accounts from 

1999 to 2003 or, for selected water-supply systems, an increasing rate of growth. Results showed that total municipal water 

use could increase about 120 percent to 55 Mgal/d, residential 

water use could increase about 160 percent to 26 Mgal/d, 

nonresidential water use could increase about 122 percent 

to 18 Mgal/d, and public use and losses could double and 

increase to 12 Mgal/d. For both scenarios the model assumed 

that the Duck River would supply all future surface-water 

needs in the study area, that ground-water resources would 

be sufficient to meet growing demands of the water-supply 

systems that depend on ground water, and that the amount of 

surface water sold to water-supply systems primarily dependent on ground water would remain the same through 2030. 

Introduction

A continuing assessment of water availability and 

demand is basic to the economic health and future of the State 

of Tennessee. Population growth in many parts of the State has 

resulted in increased competition for available water resources. 

This competition includes off-stream uses for domestic, 

agricultural, and industrial use as well as in-stream use for 

maintenance of aquatic habitat and species diversity. Accurate 

water-use1 information and water-demand projections are 

required for sound management decisions within this competitive framework. 

The Tennessee Duck River Agency (TDRA), the Duck 

River Agency Technical Advisory Committee (DRATAC), 

and the Duck River Water Resources Council (DRWRC) have 

recognized that population growth in the upper Duck River 

watershed could further increase water-supply demands. Past 

studies in the upper Duck River basin include water-demand 

projections for the period 2000 to 2050 developed by the U.S. 

Geological Survey (USGS) for Bedford, Marshall, Maury, and 

southern Williamson Counties in 1993 (Hutson and Schwarz, 

1996) and for Coffee County in 2001 (Susan S. Hutson, U.S. 

Geological Survey, written commun., 2001). During 2002, 

estimates of water withdrawals between 1981 and 2000 (Randall Braker, General Manager, Duck River Utility Commission, written commun., 2004) and water-demand projections 

were input to a watershed model, Oasis, as part of a waterneeds analysis of the upper Duck River watershed by HydroLogics, Inc. (Larry A. Murdock, Executive Director, Tennessee 

Duck River Agency, written commun., 2004). While these 

analyses indicated that the natural flows in the upper Duck 

River could meet the water-supply needs of the watershed, 

continuing growth and changing demographics highlight the 

need for periodic updates.

Purpose and Scope

This report provides estimates of water demand for the 

upper Duck River watershed through 2030. Water-demand 

estimates are limited to municipal water delivered to residential, commercial, and industrial customers and public use 

1

 Terms in bold can be found in the glossary.

Estimated Use of Water in the Upper Duck River 

Watershed, Central Tennessee, and Water-Demand 

Projections through 2030 

By Susan S. Hutson
2 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

and losses. The investigation includes an inventory of the 

municipal water use in the study area. An inventory of private 

wells for industrial, irrigation, or residential purposes or an 

assessment of the effect of water withdrawals or return flow 

on streamflow was not included in the study. For this study, 

the upper Duck River watershed study area is divided into 

four municipal water-service areas (WSAs), whose boundaries closely coincide with their respective county boundaries. 

The four WSAs are Bedford, Coffee, Marshall, and Maurysouthern Williamson (fig. 1). Water-demand estimates were 

prepared only for water-supply systems that depend on the 

upper Duck River. Future water demand from the Elk, Barren 

Fork, or Cumberland Rivers was not considered. 

Approach

The following approach was used to characterize water 

use and estimate future water demand for the upper Duck 

River watershed study area.

•	 Compile historical water-use data. 

•	 Construct base-year modeling scenarios from watersupply system monthly summary billing account 

records and climatological data. 

•	 Determine a rate of future growth for the residential 

and nonresidential customers based on short-term 

trends in billing account records and guidance from 

local and regional officials and planners and watersupply system managers. 

•	 Calibrate constant-rate water-demand models. 

•	 Simulate water demand using the Institute for Water 

Resources–Municipal and Industrial Needs Water 

Demand Management Suite software (IWR-MAIN).

Hydrologic Setting

The Duck River is a tributary to the Tennessee River and 

drains parts of the Highland Rim and Central Basin physiographic regions of central Tennessee (Miller, 1974; fig. 2). 

The climate of the area is moderate, and long-term precipitation ranges from 56 inches per year in the western part of the 

watershed to 60 inches in the eastern part of the watershed 

(Blaise L. Merchlewitz, National Forecast Office, Memphis, 

Tennessee, written commun., April 2004). The river flows 

from the dissected limestone highlands in northern Coffee 

County into Normandy Reservoir, which was completed by 

the Tennessee Valley Authority (TVA) in 1976. The reservoir, 

with a capacity of 117,000 acre-feet and a normal maximum 

headwater elevation of 875 feet, is used for flood control, 

water supply, water-quality enhancements, and recreation. 

Normandy Reservoir supplied 5.20 million gallons per 

day (Mgal/d) to Manchester, Tullahoma, and other communities in Coffee County during 2000. Downstream from 

Normandy Dam, the river flows into Bedford County and 

through the city of Shelbyville where municipal withdrawals were 5.74 Mgal/d during 2000. There are no major urban 

areas as the river traverses Marshall County, although the river 

supplied 2.76 Mgal/d during 2000 to the city of Lewisburg and 

other smaller communities. In Maury County, the river supplies water to the city of Columbia (10.6 Mgal/d during 2000) 

and, beginning in 2003, the city of Spring Hill (0.48 Mgal/d). 

The total drainage area of the watershed at the western Maury 

County boundary is 1,700 square miles. Ground-water use 

for municipal supply in the watershed was about 2.01 Mgal/d 

during 2000 for the cities of Chapel Hill, Mount Pleasant, 

and Wartrace.

Water Use

Water withdrawals for Bedford, Coffee, Marshall, and 

Maury Counties in the upper Duck River watershed study 

area totaled 28.6 Mgal/d for municipal supply, self-supplied 

industry, and self-supplied irrigation during 2000 (U.S. Geological Survey, June 2004; table 1). Withdrawals from private 

wells or springs for residential use, from farm ponds, other 

surface-water sources, wells, or springs for livestock watering 

were not estimated. Nearly all of the water withdrawals were 

from the upper Duck River (about 92 percent or 26.4 Mgal/d). 

The remaining ground-water withdrawals (2.26 Mgal/d) were 

from the Ordovician carbonate and Mississippi carbonate rock 

aquifers (fig. 2). Nearly all of the ground-water public-supply 

withdrawals were from the Ordovician carbonate aquifer 

(2.01 Mgal/d; Webbers, 2003). 

During 2000, most of the water withdrawals in the study 

area were for municipal supply (92 percent or 26.3 Mgal/d). 

Industrial withdrawals from surface water were 1.44 Mgal/d 

and from ground water about 0.04 Mgal/d. Irrigation water 

withdrawals of 0.85 Mgal/d were chiefly from surface water 

and mostly used for golf course irrigation (0.77 Mgal/d). The 

Maury-southern Williamson WSA accounted for 47 percent of 

the total water withdrawals or 13.4 Mgal/d, 47 percent of the 

total surface-water withdrawals or 12.3 Mgal/d, and 49 percent 

of the total ground-water withdrawals or 1.1 Mgal/d (table 1). 

The remaining withdrawals occurred in the Bedford (23 percent or 6.58 Mgal/d), Coffee (20 percent or 5.66 Mgal/d), and 

Marshall (10 percent or 3.00 Mgal/d) WSAs. 

Water-use trends based on calendar year data indicate 

that public-supply water withdrawals increased 46 percent 

or 8.3 Mgal/d (from 18.0 to 26.3 Mgal/d) from 1981 to 2000 

(1981 data, Alexander and others, 1984; 1985, 1990, 1995, and 

2000 data, U.S. Geological Survey, 2004; table 2). Most of the 

increase in water use was from surface water (7.40 Mgal/d), 

although the greatest percentage increase was from ground 

water (82 percent, from 1.11 to 2.02 Mgal/d). Industrial 

water withdrawals decreased from 40.2 Mgal/d in 1981 to 

1.48 Mgal/d in 2000. During 1981, nearly all of the industrial 

water use was by the chemical industry predominantly for 
Water Use 

3

Base from U.S. Geological Surveydigital data, 1:250,000, Albers projection,Standard parallels 29°30'N and 45°30'N,central meridian 96°00'W

Normandy 

Reservoir

Duck River

MAURY

HICKMAN

BEDFORD

COFFEE

MARSHALL

LEWIS

DICKSON

WILLIAMSON

GILES

MOORE

LAWRENCE

LINCOLN

RUTHERFORD

FRANKLIN

PERRY

HUMPHREYS

Columbia

Shelbyville

Lewisburg Manchester

Centerville

Tullahoma

Spring Hill

Mount Pleasant

Lynchburg

Dickson

Chapel Hill

Hohenwald Wartrace

Bell Buckle

Cornersville

Eagleville

Flat Creek Big Swan Creek 

Piney River

Silver Creek

Leiper’s Creek

Fountain Creek North Fork Creek Bear Creek Big Rock Creek Lytle Creek Sugar Creek Flat Creek Duck River Duck River

87° 86° 30' 86°

35° 30'

36°

Garrison Fork Creek Wartrace Creek

Carters Creek

85°58'50"

Maury-southern Williamson

water-service area

Bedford

water-service area

Marshall

water-service area

Coffee

water-service area

LOCATION OF DUCK RIVER WATERSHED IN TENNESSEE

0 10 20 MILES0 10 20 KILOMETERS

Figure 1. Upper Duck River study area and the Maury-southern Williamson, Marshall, Bedford, and Coffee water-service areas.
4 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

washing phosphate ore and processing elemental phosphorous 

and occurred downstream from the city of Columbia and the 

area of water-supply concerns in the watershed. Similarly, selfsupplied industrial withdrawals during 2000 were principally 

for the chemical industry and also occurred downstream from 

the city of Columbia (U.S. Geological Survey, 2004). During 

this same period, the study area population excluding southern 

Williamson County increased 32 percent from 138,300 persons to 181,870 persons (table 2).

In 2002, estimates of long-term surface-water withdrawals were compiled by DRATAC as part of a water-needs 

analysis of the upper Duck River watershed conducted 

by HydroLogics, Inc. (Randall Braker, General Manager, 

Duck River Utility Commission, written commun., 2004; 

fig. 3). The estimates were based on fiscal-year (FY) watersales data (July 1 to June 30) for 1981 through 2000 with a 

multiplicative factor of 1.20 to account for public use and 

losses. This FY data set represents the only complete, readily available set of annual estimates of water withdrawals for 

the study area. Estimates of water withdrawals for the Duck 

River Utility Commission were compiled from the water sales 

for Manchester Water Department and Tullahoma Board of 

Utilities. From FY1981 to FY2000, surface-water withdrawals increased 39 percent from 15.2 to 21.2 Mgal/d. The FY 

data indicate that water demand has steadily increased for all 

water-supply systems with some annual variability. By volume, withdrawals increased the most for the Columbia Water 

System (3.07 Mgal/d); by percentage, withdrawals increased 

the most for the Bedford County Utility District (100 percent, 1993–2000 [0.60 Mgal/d to 1.20 Mgal/d, respectively]) 

followed by the Manchester Water Department (80 percent, 

1981–2000 [1.14 Mgal/d to 2.06 Mgal/d, respectively]).

Figure 2. Physiographic regions and major aquifers in the upper Duck River watershed.

Central Basin Eastern Highland Rim

Normandy Lake

Duck River

MAURY HICKMAN

BEDFORD COFFEE

MARSHALL

LEWIS

DICKSON

WILLIAMSON

GILES MOORE LAWRENCE

RUTHERFORD

FRANKLIN

PERRY

HUMPHREYS

Columbia

Lewisburg Shelbyville

Manchester

Centerville

Tullahoma

Spring

Hill

Mount 

Pleasant

Dickson

Chapel Hill

Wartrace

Bell Buckle

Cornersville

Flat Creek

Piney River

Creek

Fountain Creek

North Fork Creek

Big Rock Creek

Duck River

87° 86° 30' 86°

35° 30'

36°

Garrison Fork Creek

Base from U.S. Geological Survey

digital data, 1:250,000, Albers projection,

Standard parallels 29°30'N and 45°30'N,

central meridian 96°00'W

87° 30'

Western Highland Rim

Duck River

Carters Creek

Leiper’s

0 10 20 MILES

0 10 20 KILOMETERS

Physiography modified

from Miller, 1974

Major aquifers in the eastern Highland Rim 

 Mississippian carbonate aquifers

 - Fort Payne Formation

 - Fort Payne Formation (gravel regolith)

Major aquifers in the western Highland Rim 

 Mississippian carbonate aquifers

 - Warsaw Limestone

 - Fort Payne Formation (gravel regolith)

Major aquifers in the Central Basin 

 Ordovician carbonate aquifers

 - Bigby-Cannon Limestone

 - Ridley Limestone

LOCATION OF DUCK RIVER WATERSHED IN TENNESSEE
Estimated Water Demand 5

Estimated Water Demand

Water demand was estimated using the IWR-MAIN 

Water Demand Management Suite software. The Forecast 

Manager module of the IWR-MAIN software provides 

accounting and analytical tools for estimating municipal 

demand. The user’s manual and suite description provide 

additional details for much of the discussion presented in this 

section of this report (Planning and Management Consultants, 

Ltd., 1999). The water-use forecasting algorithm of Forecast 

Manager is built to operate on data corresponding to a study 

area or subarea (such as a WSA or a water-supply system), 

water-use sectors and subsectors, months, and forecast years. 

Forecasts were devised for the residential (combined singleand multifamily subsectors) and nonresidential (combined or 

separate commercial and industrial subsectors) sectors and for 

public use and losses. 

Several assumptions about the character of the data 

and about the structure of climatological, demographic, and 

socioeconomic conditions in future years were necessary to 

estimate water demand through 2030. The model assumed that 

the Duck River would supply all future surface-water needs 

within the study area, that available ground-water resources 

would meet the demands of the ground-water-based watersupply systems, and that the sale of supplemental surface 

water to ground-water-based water-supply systems in 2000 

would remain constant through 2030. Other assumptions are 

detailed within each of the respective sections in this report. 

Table 1. Surface-water and ground-water withdrawals by water-use category in the upper Duck River watershed, 2000.

[Totals may not add to sums because of independent rounding. Population is expressed to two decimal places. Water withdrawal values are expressed 

as three significant figures or if the value is less than 1, to two decimal places]

Water-service 

area

Population,a

in thousands

Municipal supply Self-supplied

industry

Self-supplied 

irrigation Study area

Surface

water 

Ground

water 

Surface 

water

Ground 

water

Surface

water 

Ground

water 

Surface

water 

Ground

water 

Total

water

Million gallons per day

Bedford 37.59 5.74 0.83 0.00 0.00 0.01 0.00 5.75 0.83 6.58

Coffee 48.01 5.20 .01 .00 .040 .36 .05 5.56 .10 5.66

Marshall 26.77 2.76 .15 .00 .00 .01 .08 2.77 .23 3.00

Maury-southern 

Williamson 69.50b 10.6 1.03 1.44 .00 .27 .07 12.3 1.10 13.4

Watershed total 181.87b 24.3 2.02 1.44 .04 .65 .20 26.4 2.26 28.6

a

 Population and water withdrawals are from the U.S. Geological Survey, Aggregated Water Use Data System (2004)

b

 Population total excludes southern Williamson County

Table 2. Total surface-water and ground-water withdrawals for municipal-supply use in 1981, 1985, 1990, 1995, and 2000 for the 

upper Duck River watershed study area.

[Mgal/d, million gallons per day. Totals may not add to sums because of independent rounding. Population and water-use data are from Alexander and others 

(1981); population and water withdrawals for 1985–2000 are from U.S. Geological Survey (2004)]

Municipal supply

Water withdrawals, in Mgal/d Rate of change 

in use from

1981 to 2000,

in Mgal/d

Rate of change 

in use from 

1981 to 2000, 

in percent 1981 1985 1990 1995 2000

Ground water 1.11 1.40 1.48 1.85 2.02 0.91 82

Surface water 16.9 20.4 19.5 22.3 24.3 7.40 44

Total water 18.0 21.8 21.0 24.1 26.3 8.3 46

Population, in thousands

Study area populationa 138.33 142.80 147.10 166.94 181.87 32

a

 Excludes population for southern Williamson County
6 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

Tullahoma Board of Utilities

1.5

2.0

2.5

3.0

WATER WITHDRAWALS BY WATER SYSTEM, MILLION GALLONS PER DAY

Total water use

14

16

18

20

22

Columbia Water System

7

9

11

Manchester Water System

1.0

1.5

2.0

2.5

Shelbyville Water System

2

3

4

1982 1984 1986 1988 1990 1992 1994 1996 1998 2000

Lewisburg Water System 1

2

3

Bedford County Board of Utilities

0.5

1.0

1.5

Figure 3. Historic water withdrawals for Columbia Water System, Shelbyville Water System, 

Lewisburg Water System, Tullahoma Board of Utilities, Manchester Water System, and 

Bedford County Board of Utilities, Tennessee, 1981–2000.

Modeling Scenarios

Water use is the expression of the cumulative effect of 

several factors on customer decision-making. A minimum 

amount of water is required each day (water requirement) to 

meet basic household needs for drinking water, food preparation, washing clothes and dishes, and sanitary purposes (U.S. 

Army Corps of Engineers, 1988). Likewise, commercial and 

industrial facilities have basic process and technological water 

requirements. The behavior of water users also responds to 

changes in the price of water, income, water conservation 

initiatives, and such physical factors as increases in temperature and decreases in precipitation (Sellers and North, 1990; 

U.S. Army Corps of Engineers, 1988). Several studies describe 

how water-demand patterns, like weather patterns, are cyclic, 

usually with greater outdoor water use occurring during the 

summer season and that the duration of extremes (hot-dry or 

wet-cold) can amplify the seasonal change in water demand 

(Linaweaver, 1965; Maidment and others, 1985; Dietemann, 

1998; Vickers, 2001; Dziegielewski and others, 2004; and 

Kiefer, 2006). 
Estimated Water Demand 7

To represent the variability in water use across the study 

area, two base years were selected to cover the range of wateruse values experienced over past years. Recent years were 

selected because they already encompass the results of past 

trends, and would, therefore, provide more accurate values. 

The years 2000 and 2003 were found to be representative of 

drought and typical weather conditions and, therefore, were 

selected to represent base-year conditions for the modeling 

scenarios. The year 2000 was warmer and drier than normal climatological conditions for the period 1971 to 2000. 

The mean monthly maximum temperature (MMMT) was 

9.57 °F above normal, and the departure from normal precipitation (DP) was 6.39 inches below normal at the Columbia site (fig. 4 and table 3). At the Tullahoma site, the MMMT 

was 7.49 °F above normal, and DP was 1.93 inches below 

normal. Year 2003 was cooler and wetter than normal. The 

MMMT was 3.14 °F below normal and DP was 5.81 inches 

above normal at the Columbia site; MMMT was 3.48 °F below 

normal and DP was 12.3 inches above normal at the Tullahoma site.

The most pronounced rainfall deficit in the watershed 

occurred from 1985 to 1988 (Blaise L. Merchlewitz, National 

Forecast Office, Memphis, Tennessee, written commun., 

April 2004). Cumulatively, DP was –52.8 inches for the 

Columbia site and –50.8 inches for the Tullahoma site for this 

period. For comparison to 2000 and 2003, in 1988, DP deviated –14.6 inches at the Columbia site (table 3) and per capita 

use averaged 193 gallons per person per day (James Clark, 

General Manager, Columbia Water System, written commun., 

April 2004).

Scenario 1 (base year 2003) incorporates the trend 

in recent growth (1999 to 2003) in customer accounts and 

reflects typical weather conditions with relatively low per 

household water use. Scenario 2 (base year 2000) considers 

drier and warmer weather (drought) conditions with relatively 

high per household water use and either incorporates the 

recent growth in customer accounts or, for some water-supply 

systems, an increasing rate of growth. The range of values 

for household use varies monthly and annually according to 

the water-use patterns characteristic of each of the modeled 

public-supply systems.

Municipal water demand in the upper Duck River watershed study area was estimated through 2030 for residential, 

nonresidential, and public use and losses for two scenarios 

for each of the 14 water-supply systems that depend on water 

from the upper Duck River (table 4). The years 2010 and 2020 

0 10 20 MILES

0 10 20 KILOMETERS

Normandy 

Reservoir

Duck River

MAURY

HICKMAN

BEDFORD

COFFEE

MARSHALL

LEWIS

DICKSON

WILLIAMSON

GILES

MOORE

LAWRENCE

LINCOLN

RUTHERFORD

FRANKLIN

PERRY

HUMPHREYS

Columbia

Shelbyville

Lewisburg Manchester

Centerville

Tullahoma

Spring Hill

Mount Pleasant

Dickson

Chapel Hill

Hohenwald Wartrace

Bell Buckle

Cornersville

Eagleville

Flat Creek

Big Swan Creek 

Piney River

Silver Creek

Leiper’s Creek

Fountain Creek

North Fork Creek

Bear Creek

Big Rock Creek

Lytle Creek

 Sugar Creek

Flat Creek

Duck River

Duck River

87° 86° 30' 86°

35° 30'

36°

Garrison Fork Creek

Wartrace Creek

Carters Creek

85°58'50"

Base from U.S. Geological Survey

digital data, 1:250,000, Albers projection,

Standard parallels 29°30'N and 45°30'N,

central meridian 96°00'W

EXPLANATION

Location of the National Oceanic and 

 Atmospheric Administration weather

 observation sites

Water-service area

Figure 4. Location of the four National Oceanic and Atmospheric Administration cooperative weather observation sites in the 

upper Duck River watershed.
8 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

Table 3. Normal climatological conditions (based on climatological records from National Oceanic and Atmospheric 

Administration [NOAA] from 1971 to 2000) and mean monthly maximum air temperature and monthly rainfall for 1988, 2000, 

and 2003 for Columbia and Tullahoma NOAA cooperative weather-observation sites. 

[Above normal mean maximum air temperature and below normal rainfall values are in bold text. Air temperature is in Fahrenheit degrees, precipitation 

is in inches; Jan, January; Feb, February; Mar, March; Apr, April; Aug, August; Sept, September; Oct, October; Nov, November; Dec, December]

Month

Normal 1988 2000 2003

Maximum

air

temperature

Precipitation

Mean

maximum

air 

temperature

Departure

from normal

precipitation

Mean 

maximum

air 

temperature

Departure

from normal

precipitation

Mean

maximum

air 

temperature

Departure

from normal

precipitation

Columbia NOAA cooperative weather-observation site

Jan 46.1 4.66 42.6 –0.13 48.2 –1.23 42.0 –3.04

Feb 51.4 4.35 50.1 –1.55 57.4 .80 46.9 6.39

Mar 60.3 6.25 60.8 –3.93 65.5 –.99 62.0 –3.75

Apr 69.4 4.85 71.4 –.20 66.6 1.66 72.7 .05

May 77.1 5.57 79.4 –4.06 79.3 –.79 76.7 3.97

June 84.8 4.14 90.5 –3.48 85.2 –.38 82.6 1.43

July 88.5 5.03 89.1 .25 89.0 –1.83 87.3 1.40

Aug 88.1 3.48 92.1 –1.04 89.5 –1.18 89.0 –.03

Sept 81.8 3.94 81.2 1.26 84.0 –.40 81.7 2.79

Oct 71.5 3.55 66.0 –2.16 75.8 –3.45 71.3 –2.05

Nov 60.1 4.85 63.4 1.30 58.4 1.90 64.1 1.04

Dec 50.1 5.46 51.4 –.83 40.3 –.50 49.6 –2.39

Departure 

from 

normal

8.86 –14.6 9.57 –6.39 –3.14 5.81

Tullahoma NOAA cooperative weather-observation site

Jan 46.2 5.51 43.7 –0.28 47.7 –0.92 41.8 –2.90

Feb 50.9 4.86 50.9 –1.35 58.4 –1.27 48.3 5.72

Mar 60.0 6.73 62.2 –4.01 64.8 .21 62.5 –3.06

Apr 69.0 4.94 70.6 .62 66.3 3.89 70.7 .50

May 76.2 5.28 79.1 –4.23 79.4 –.55 75.2 7.99

June 83.9 4.74 89.2 –3.71 83.9 2.31 80.9 1.69

July 87.1 4.8 89.0 – .30 88.2 –2.53 84.9 3.29

Aug 86.6 3.52 90.3 –1.36 88.2 –1.57 87.2 1.14

Sept 80.8 4.33 80.2 1.01 79.1 .8 80.2 1.32

Oct 70.8 3.89 67.1 –1.3 74.6 –3.39 71.2 –2.37

Nov 59.3 5.47 62.7 3.64 56.6 .63 65.1 .48

Dec 49.8 5.97 52.9 –.057 40.6 .46 49.1 –1.48

Departure 

from 

normal

17.4 –11.8 7.49 –1.93 –3.48 12.3
Estimated Water Demand 9

Table 4. Water-supply systems and sources of supply in the upper Duck River watershed, 2000 and 2003.

[Water-demand projections were determined for the water-supply systems indicated in bold type. West Warren–Viola distributes water to customers in Coffee 

County, but withdraws water from the Barren Fork River. Mgal/d, million gallons per day; WSA, water-service area; —, no transaction; do., ditto; WS, Water 

System; BU, Board of Utilities; gw, ground water; CUD, County Utility District; UC, Utility Commission; WD, Water Department; MHP, Mobile Home Park; 

MCBPU, Marshall County Board of Public Utilities; MCWS, Maury County Water System; UD, Utility District; 0.000, line connection but no transaction] 

Water-supply system Source of supply

2000 2003

Withdrawals Purchased 

water Withdrawals Purchased water

Million gallons per day

Bedford WSA

Shelbyville Water System Duck River 4.44 — 4.45 —

Bedford County Utility District Duck River 1.30 — 1.41 —

do. Shelbyville WS — 0.000 — 0.001

do. Tullahoma BU — .052 — .001

Wartrace Water System Cascade Spring (gw) .830 — .812 —

Bell Buckle Water System Bedford CUD — .031 — .035

do. Wartrace WS — .112 — .172

Flat Creek Cooperative Shelbyville WS — .163 — .162

do. Tullahoma BU — .001 — .002

Jarrell Mobile Home Park well .004 — .004 —

Coffee WSA

Manchester Water Department Duck River UC — 2.41 — 2.22

Tullahoma Board of Utilities Duck River UC — 2.76 — 2.81

Duck River Utility Commission Duck River 5.20 — 5.04 —

Hillsville Utility District Manchester WD — .596 — .549

Stacy Anne’s MHP well .009 — .020 —

West Warren–Viola Utility District Barren Fork River 1.27 — 1.54 —

Marshall WSA

Chapel Hill Water System MCBPU 0.017 — 0.003

do. Town Well 0.152 — 0.154 —

Marshall County BPU Lewisburg WS — .496 — .526

do. Cornersville WD — .016 — .012

do. Chapel Hill WS — .058 — .051

Cornersville Water Department Lewisburg WS — .121 — .164

Petersburg Water System Fayetteville WS — .065 — .061

Lewisburg Water System Duck River 2.76 — 2.80 —

Maury-southern Williamson WSA

Columbia Water Department Duck River 10.6 — 9.57 —

Mount Pleasant Water System Springs 1.03 — 1.01 —

do. Columbia WS .000 — — 0.03

Spring Hill Water Department Duck River — — .48 —

do. Columbia WS — 1.30 — .96

do. MCWS — .000 — .08

Maury County Water System Columbia WS — 1.05 — 1.07

do. Spring Hill WD — — — .102

HB & TS Utility District Spring Hill WD — .406 — .137

do. Harpeth Valley UD — .913 — 1.24
10 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

are intermediate modeling intervals that capture short-term 

changes in the rate of growth for some water-supply systems. 

Projected water demand for a WSA is the sum of the municipal water demand for the individual systems. The projected 

water demand for the study area is the sum of the municipal 

water demand for the Bedford, Coffee, Marshall, and Maurysouthern Williamson WSAs. 

Water-Use Projections

Water-use projections for the upper Duck River watershed study area were determined using a constant-rate method 

based on the average monthly water use per account and 

the estimated number of accounts per water-supply system 

projected through 2030. The base-year (2000 or 2003) rate of 

use per account (q in equation 1) was determined from baseyear monthly water use and the number of monthly residential 

accounts. The quantity of water use in the sector, month, and 

forecast year was calculated as follows and is expressed in 

million gallons per day for this study:

Qs,m,y = Ns,m,y  ́ qs,m,b  ́ dm, (1)

where,

Q is gallons of water used in sector (s) in 

month (m) in year (y),

N is the number of accounts in sector (s) in 

month (m) in year (y), 

q is the average daily water-use rate per 

account in sector (s) in month (m) in 

base year (b), and

d is the number of days in month (m). 

For each residential modeling scenario, the water use per 

residential account for 2000 and for 2003 remained constant 

for all of the forecast years. The change in number of residential accounts (N in equation 1) explains the change in forecast 

from year to year. The rate of change in residential accounts 

rather than in county or WSA population or in population 

served by water-supply systems was used as the factor determining N in equation 1 (U.S. Army Corps of Engineers, 1988). 

In addition to accounting for population growth, the number 

of residential records also included new connections to water 

lines by residences previously supplied by individual wells or 

springs. The recent rate of increase in the customer accounts 

in each of the WSAs has been greater than the rate of increase 

in county population projected by the University of Tennessee, Center for Business and Economic Research (Tennessee 

Advisory Commission on Intergovernmental Relations and 

The University of Tennessee, 2003). Local officials, local 

and regional development agencies, and water-supply system 

managers also provided guidance in developing residential and 

nonresidential rates of growth for estimating N for the model 

for 2010, 2020, and 2030. 

For nonresidential water-use projections, future changes 

in water use per account in the commercial and industrial 

subsectors could not be determined. Therefore, water use 

per account for 2000 and for 2003 remained constant for the 

forecast years for each subsector. The projected change in the 

number of commercial or industrial accounts (N in equation 1) 

determines the change in the water-use forecast from year to 

year. The number of commercial accounts for the nonresidential model in future years was determined by applying 

recent or expected future rates of growth to the baseline year 

accounts. The number of industrial accounts was estimated 

differently. Baseline conditions for industrial accounts generally were kept constant through 2030 except for the addition 

of water needed for newly built or planned industrial parks—

likely locations of new industry in the study area—in the 

Coffee and Marshall WSAs. 

Public use and losses were estimated as a percentage 

of the total municipal use for each water-supply system. For 

the base year of 2000 or 2003, the percentage varied among 

systems and often reflected different operational, maintenance, 

and community needs. The base-year percentages were used in 

each of the forecast years for each of the systems. Across the 

14 water-supply systems, percentages of public use and losses 

ranged from about 8 to 39 percent. 

Data Preparation/Model Input

Residential, commercial, and industrial billing account 

data and percentages of public use and losses were prepared 

as input to the water-use models contained in IWR-MAIN 

for 2010, 2020, and 2030 for the water-supply systems that 

depend on the upper Duck River. Water-supply systems that 

withdrew ground water were not modeled. Base-year data 

were prepared for 2000 (drought year) and 2003 (typical year) 

to calibrate two water-demand scenarios. 

For this study, monthly summary billing account 

records were used to determine per account water use, in 

gallons per account per month (converted by the IWR-MAIN 

software to gallons per account per day). Although the level 

of detail of billing varied among the water-supply systems—

primarily related to size of water-supply system and the choice 

of financial accounting system format—water use generally 

could be characterized for the water-supply systems as inside 

the city or outside the city for the residential, commercial, and 

industrial customer classes. The terms urban and rural are used 

in this report to simplify the terminology. Urban refers to the 

area inside the corporate boundaries of a city, and rural refers 

to the areas outside the corporate boundaries and may include 

subdivisions and farms. Estimates of water use per account are 

based on metered data and are considered reliable. Although 

length of billing cycle per account generally varies from month 

to month, the total number of billed days over the year for each 

account approximated 1 year and is not considered problematic. For data analysis and modeling purposes, sales to a 

water-supply system were assigned to the water-supply system 

purchasing the water and were modeled separately. 

A smaller subset of customer billing record data was 

selected for analysis for this study partly because the data 

for each water-supply system are extensive and sometimes 
Estimated Water Demand 11

Table 5. Average per account use for selected water-supply systems in the upper Duck River watershed study area and billing 

account sectors for 2000 and 2003.

[gal/d, gallons per day; Mgal/d, million gallons per day]

Columbia Water System

Residential Commercial Industrial

Urban Rural Urban Rural

2000 2003

2000 2003 2000 2003 2000 2003

Per account use, 

in gal/d

180 165 227 209 861a 812a 66,692a 61,684a

Accounts 11,182 11,548 4,430 4,722 2,027a 2,105a 28a 25a

Sector use, 

in Mgal/d

2.01 1.91 1.00 .99 1.75 1.71 1.87 1.54

Lewisburg Water System

Residential Commercial

Urban Rural

2000 2003

2000 2003 2000 2003

Per account use, 

in gal/d

140 132 193 182 1,161b 817b

Accounts 3,595 3,603 957 984 634b 641b

Sector use, 

in Mgal/d

.503 .475 .185 .179 .736 .524

Shelbyville Water System

Residential Commercial Industrial

Urban Rural

2000 2003 2000 2003 2000 2003 2000 2003

Per account use, 

in gal/d

141 139 195 173 585a 571a 29,479 a 31,095a

Accounts 6,114 6,346 396 421 884a 939a 49a 49a

Sector use,

in Mgal/d

.862 .882 .077 .073 .517 .536 1.45 1.52

Tullahoma Utility Board

Residential Commercial

Urban Rural Urban Rural

2000 2003 2000 2003 2000 2003 2000 2003

Per account use, 

in gal/d

161 154 170 167 759b 767b 588b 666b

Accounts 6,684 6,891 881 1,025 950b 997b 48b 50b

Sector use, 

in Mgal/d

1.08 1.06 .150 .171 .721 .765 .028 .033

a

 Urban and rural accounts are combined

b

 Commercial and industrial facilities are classified as commercial

difficult to access. Historical data most often were maintained as paper files—often archived, sometimes not readily 

available, and sometimes not available at all. At a minimum, 

readily available monthly data were collected for each system 

for 1999 through 2003 (the period of increasing residential and 

commercial growth in the study area). More complete records 

were analyzed for the Columbia Water System (billing records 

from 1980 to 2003) and the Duck River Utility Commission 

(water-withdrawal records, August 1981 to 2003). For some 

water-supply systems, only annual summary data were readily 

available and, therefore, were used to calibrate the models for 

those systems. 

Some general characteristics of sector water use were 

examined from customer accounts for 2000 to 2003 using 

Columbia Water System, Lewisburg Water System, Shelbyville 

Water System, and Tullahoma Utility Board data (table 5). 

These four water-supply systems serve both urban and rural 

residential, commercial, and industrial customers and are representative of the other water-supply systems in the study area. 

As indicated in table 5, most of the residential accounts are 
12 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

urban, and these households consistently use less water than 

rural households. For 2003, the percentage of urban residential customers for the four water-supply systems ranged from 

71 to 94 percent, and water use ranged from 132 to 165 gallons per household per day. Rural water use for 2003 ranged 

from 167 to 209 gallons per household per day. For modeling 

purposes, the percentage of urban households relative to rural 

households was held constant for the forecast years. 

Average annual combined urban and rural household use 

was different for each water-supply system but consistently 

greater in 2000 than in 2003 (table 6). Further, a distinct summer season is evident from the monthly water-use data. For 

example, for the Columbia Water System, household use was 

above average in June, July, August, and September (peak 

month). For 2000 (drought conditions), September household 

usage was 1.26 times greater than the average use for the year; 

for 2003 (typical weather conditions), September household 

usage was 1.11 times greater than the average usage. Outdoor 

usage usually accounts for nearly all the seasonal difference 

in water use (U.S. Army Corps of Engineers, 1988). This 

ratio between peak month and average annual use varied only 

slightly among the water-supply systems for 2000 and 2003. 

On average, less water is used in March than in the other 

months for both years, suggesting that March likely represents 

typical indoor household usage.

Monthly nonresidential use indicated a seasonal pattern 

similar to residential use. Per account use was above average 

during the summer season. For the Columbia Water System, 

combined commercial and industrial use was above average in June, July, August, and September (peak month). For 

2000, September nonresidential usage was 1.28 times greater 

than the average nonresidential use for the year; for 2003, 

September usage was 1.23 times greater than the average use. 

Summer seasonal usage may be attributed to water cooling 

of on-site air conditioning systems and landscape irrigation. 

Year-to-year variation of nonresidential use, however, is more 

difficult to assess as water requirements linked to manufacturing processes or manufacturing output may change. Although 

increased water recycling and reuse were not considered in 

this study, these activities can significantly reduce water use 

(Vickers, 2001).

Most of the rapid growth in customer accounts in the 

watershed from 1999 to 2003 occurred in the residential and 

commercial sectors. This growth trend is the basis for the 

estimates of the number of future customer accounts by watersupply systems for scenario 1. For scenario 2, any increase in 

the number of accounts from the expected trend was considered in consultation with municipal officials, local and regional 

planning groups, and water-supply managers. The number of 

industrial accounts or associated water use had either stabilized or declined from 1999 to 2003. For the two scenarios, 

industrial water use was held constant throughout the modeling years except for the addition of newly built or planned 

industrial parks. The model input reflects the decision that the 

industrial parks would be operational by 2020, and the capacity 

of the pipelines to the industrial parks would be fully utilized. 

Changes in the assumed patterns of industrial growth in the 

study area could affect the projected industrial water demand. 

Projected Water Demand

Municipal water demand for 2010, 2020, and 2030 for the 

upper Duck River watershed study area was estimated using 

the constant-rate models contained in the IWR-MAIN Water 

Demand Management Suite software. The number of accounts 

and the associated water use for each water-supply system for 

2000 and 2003 were input to the Forecast-Management system 

to estimate water demand for the residential and nonresidential 

sectors. Public use and losses were modeled as a percentage of the total water-supply system demand. Results were 

aggregated to the WSA and then to the study area (table 7). 

Although 2003 data are used as base-year data for scenario 1, 

Table 6. Average modeled household use for selected water-supply systems in the upper Duck River watershed study area 

for 2000 and 2003. 

[Values expressed in gallons per household per day; above annual average household water-use values for year are in bold text; greatest average household 

water-use values for year are underlined; Jan, January; Feb, February; Mar, March; Apr, April; Aug, August; Sept, September; Oct, October; Nov, November; 

Dec, December; WS, Water System; UB, Utility Board]

Water system Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Annual

average

Warmer and drier than normal climatological conditions (2000)

Columbia WS 182 187 164 177 176 200 230 215 245 184 183 179 194

Lewisburg WS 141 151 139 135 142 172 153 177 178 146 148 133 151

Shelbyville WS 152 151 142 150 144 170 176 169 182 142 156 141 156

Tullahoma UB 150 159 144 153 166 173 176 178 177 171 160 152 163

Typical of normal climatological conditions (2003)

Columbia WS 177 190 154 162 176 188 176 194 197 175 179 168 178

Lewisburg WS 143 167 119 137 142 148 153 145 156 144 133 131 143

Shelbyville WS 147 157 115 141 145 141 163 147 152 139 138 133 143

Tullahoma UB 158 168 136 143 153 162 168 169 170 149 152 152 156
Projected Water Demand 13

Table 7. Simulated water demand for the upper Duck River watershed study area for the Bedford, Coffee, Marshall, and 

Maury-southern Williamson water-service areas for 2000, 2010, 2020, and 2030.

[Scenario 1, typical climatological conditions and an expected rate of growth in customer accounts; scenario 2, drought conditions and either an expected rate 

of growth or an increasing rate of growth in customer accounts. Figures are expressed as two significant figures. Totals may not add to sums because of 

independent rounding. Percentages are based on the numbers presented in the table. WSA, water-service area]

Sector Water use, in million gallons per day (Mgal/d) Change in water use from 2000 to 2030,

in Mgal/d

Change in water use 

from 2000 to 2030, 

2000 2010 2020 2030 in percent

Bedford WSA scenario 1

Residential 1.9 2.4 3.2 4.2 2.3 121

Nonresidential 2.1 2.4 2.6 2.8 .7 33

Public use/losses 1.7 1.9 2.4 2.9 1.2 71

Total 5.7 6.7 8.1 9.9 4.2 74

Bedford WSA scenario 2

Residential 1.9 2.5 3.3 4.5 2.6 137

Nonresidential 2.1 2.4 2.6 2.9 .8 38

Public use/losses 1.7 2.1 2.4 3.0 1.3 76

Total 5.7 6.9 8.4 10 4.3 75

Coffee WSA scenario 1

Residential 2.3 2.8 3.8 5.1 2.8 122

Nonresidential 1.4 1.8 6.9 7.7 6.3 450

Public use/losses 1.3 1.5 2.0 2.7 1.4 108

Total 5.0 6.1 13 16 11 220

Coffee WSA scenario 2

Residential 2.3 2.9 3.9 5.3 3.0 130

Nonresidential 1.4 1.8 6.9 7.7 6.3 450

Public use/losses 1.3 1.6 2.2 2.9 1.6 123

Total 5.0 6.3 13 16 11 220

Marshall WSA scenario 1

Residential 1.2 1.3 1.7 2.0 0.8 67

Nonresidential .8 .6 1.2 1.3 .5 62

Public use/losses 1.1 1.1 1.3 1.5 .4 36

Total 3.0 3.0 4.2 4.8 1.8 60

Marshall WSA scenario 2

Residential 1.2 1.5 1.9 2.5 1.3 108

Nonresidential .8 .9 1.5 1.7 .9 112

Public use/losses 1.1 1.3 1.5 1.9 .8 73

Total 3.0 3.6 4.9 6.1 3.1 103

Maury-southern Williamson WSA scenario 1

Residential 5.1 7.2 10 12 6.9 135

Nonresidential 3.8 3.7 4.3 4.8 1.0 26

Public use/losses 2.0 2.3 2.9 3.5 1.5 75

Total 11 13 17 21 10 91

Maury-southern Williamson WSA scenario 2

Residential 5.1 7.5 10 13 7.9 155

Nonresidential 3.8 4.2 4.7 5.3 1.5 39

Public use/losses 2.0 2.5 3.1 3.8 1.8 90

Total 11 14 18 22 11 100

Upper Duck River watershed study area scenario 1

Residential 10 14 19 24 14 140

Nonresidential 8.1 8.5 15 17 8.9 110

Public use/losses 6.0 7.3 8.5 11 5.0 83

Total 25 30 42 51 26 104

Upper Duck River watershed study area scenario 2

Residential 10 14 19 26 16 160

Nonresidential 8.1 9.2 16 18 9.9 122

Public use/losses 6.0 7.4 9.2 12 6.0 100

Total 25 31 44 55 30 120
14 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

the measure of change in water use for scenario 1 is the same 

as for scenario 2, from 2000 through 2030 (table 7). Projected 

estimates of water demand for scenario 1 indicate that

•	 average total municipal water use could increase 

about 104 percent to 51 Mgal/d by 2030,

•	 residential water use could increase about 

140 percent to 24 Mgal/d,

•	 nonresidential water use could increase about 

110 percent to 17 Mgal/d, and 

•	 public use and losses could increase about 

83 percent to 11 Mgal/d. 

Projected estimates for scenario 2 indicate that

•	 average total municipal water use could increase 

about 120 percent to 55 Mgal/d,

•	 residential water use could increase about 

160 percent to 26 Mgal/d,

•	 nonresidential water use could increase 

about 122 percent to 18 Mgal/d, and 

•	 public use and losses could increase 

100 percent to 12 Mgal/d. 

The water demand forecast outlined in this study can be 

considered as the most likely of scenarios; however, projections are not absolute. Inconsistencies in the billing account 

data for the different water-supply systems of different age 

and design with different mixtures of customer requirements 

over the same period of time affect the water-demand projections (Kindler and Russell, 1984). The degree of uncertainty 

increases, as with any model, as the length of time of the 

projections increases. Projecting water demand through 2030 

assumes that many political, environmental, economic, and 

technical factors will be relatively constant. If the assumptions 

are changed—fewer or more industrial parks are developed in 

the study area or a shift to more or less ground water occurs—

the water demand will likely change. The water-demand models developed for this study are designed primarily to examine 

the effects that various assumptions could have on water use 

rather than as predictive tools to generate absolute values of 

future water use. The validity of the results of the modeling 

effort depends on the reliability of the assumptions.

Summary

Water-demand projections through 2030 were developed by the U.S. Geological Survey in cooperation with the 

Tennessee Duck River Agency during 2004 under the planning process to update water-demand projections once every 

5 years as proposed by the Duck River Technical Advisory 

Committee and the Duck River Water Resources Council 

and formalized in the Duck River Watershed Comprehensive 

Water Resources Plan: Part 1 Water Supply Plan—2003. The 

water-use inventory, which establishes baseline conditions for 

estimating water demand, indicated that total water withdrawals for the Bedford, Coffee, Marshall, and Maury-southern 

Williamson water-service areas were 28.6 million gallons per 

day (Mgal/d) for municipal supply, self-supplied industry, and 

self-supplied irrigation use during 2000. Water withdrawals 

from the upper Duck River provided about 92 percent of the 

total supply; the remaining 2.26 Mgal/d came from springs 

and wells. About 92 percent or 26.3 Mgal/d of the total withdrawals were for municipal supply. Industrial withdrawals 

from surface water were 1.44 Mgal/d. Irrigation withdrawals 

(0.85 Mgal/d) were chiefly from surface water and primarily 

used for golf courses. The Maury-southern Williamson waterservice area accounted for 47 percent of the total withdrawals, 

47 percent of the surface-water withdrawals, and 49 percent of 

the ground-water withdrawals.

Public-supply withdrawals increased 46 percent (from 

18.0 to 26.3 Mgal/d) from 1981 to 2000. During the same 

period, industrial withdrawals decreased from 40.2 to 

1.48 Mgal/d. The Columbia Water System increased water 

withdrawals the most during this period, 3.07 Mgal/d; by 

percentage, the Bedford County Utility District increased the 

most, 100 percent from 1993 to 2000 (from 0.60 Mgal/d to 

1.20 Mgal/d).

Future water demand was estimated using the Institute 

of Water Resources–Municipal and Industrial Needs Water 

Demand Management Suite software. Modeling scenarios 

were prepared for each water-supply system addressing the 

short-term variability of weather conditions and the long-term 

effect of water-supply system expansion. Scenario 1 considered monthly water demand under typical weather conditions as represented by monthly per account use for 2003 

and an expected rate of growth in customer accounts. For 

the upper Duck River watershed study area, total municipal 

water use could increase about 104 percent to 51 Mgal/d by 

2030. Residential water use could increase about 140 percent 

to 24 Mgal/d, nonresidential water use could increase about 

110 percent to 17 Mgal/d, and public use and losses could 

increase about 83 percent to 11 Mgal/d.

Scenario 2 considered monthly water demand under 

drought conditions as represented by monthly per account use 

during 2000 and combined either the expected rate of growth 

in customer accounts or, for some water-supply systems, a 

more rapid than expected rate of growth. Simulated water 

demand indicates that total municipal water use could increase 

about 120 percent to 55 Mgal/d. Residential water use could 

increase about 160 percent to 26 Mgal/d, nonresidential water 

use could increase about 122 percent to 18 Mgal/d, and public 

use and losses could increase 100 percent to 12 Mgal/d.

For both scenarios, the model assumed that the Duck 

River would supply all future surface-water needs within the 

study area, that available ground-water resources would meet 

the demands of the ground-water-based water-supply systems, 

and that the sale of supplemental surface-water to groundwater-based water-supply systems in 2000 would remain 

constant through 2030. 
References 15

References 

Alexander, F.M., Keck, L.A., Conn, L.G., and Wentz, S.J., 

1984, Drought-related impacts on municipal and major selfsupplied industrial water withdrawals in Tennessee—part B: 

U.S. Geological Survey Water-Resources Investigations 

Report 84-4074, 398 p.

Boland, J.J., Dziegielewski, B., Dauman, D.D., and Opitz, 

E.M., 1984, Influence of price and rate structures on municipal and industrial water use: Fort Belvoir, Virginia, U.S. 

Army Corps of Engineers Institute for Water Resources, 

Contract Report 84-c-2, 187 p.

Dietemann, A., 1998, A peek at the peak, case study—Reducing Seattle’s peak water demand: Resource Conservation 

Section, Seattle Public Utilities, 100 p.

Dunne, T., and Leopold, L.B., 1996, Water in environmental 

planning: New York, W.H. Freeman and Company, 818 p. 

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Open-File Report 03-47, 1 sheet.
16 Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee

departure from normal precipitation Normal 

precipitation minus observed precipitation.

mean monthly maximum temperature The 

average of the daily maximum air temperatures for 1 month.

monthly summary billing account 

records Total amount of water billed for 

all customers in a customer class for a billing 

cycle. Generally, a billing cycle is approximately 1 month for the water-supply systems 

in the study area. The number of days can 

vary per customer from month to month 

because of the number of days in the month, 

the meter reading schedule, or weather. 

municipal water Public-supply water delivered to residential, commercial, and industrial 

customers and includes public use and losses. 

See also public use and losses.

normal climatological conditions A climate 

normal is defined as the arithmetic mean of a 

climatological element computed over 30 consecutive years. Since records are frequently 

characterized by data inhomogeneities, 

statistical methods have been developed to 

identify and account for them. In application 

of these methods, adjustments are made so 

that earlier periods in the data record more 

closely conform to the most recent period. 

Additionally, methods have been developed 

to estimate values for missing observations. 

After such adjustments are made, the climate 

record is said to be homogeneous and serially complete. This adjusted record is said 

to be characterized by variations in trends in 

weather and climate. By using appropriately 

adjusted data records, the 30-year mean value 

will more closely reflect the average climatic 

conditions at a given station with respect to 

the instrumentation and siting conditions at 

the end of normal periods (National Climatic 

Data Center, March 2002). 

outdoor water use Water used for lawn, 

landscape, or garden watering, car washing, 

maintenance, or other similar activities.

persons per household A measure obtained 

by dividing the number of people living in 

owner-occupied units by the total number of 

owner-occupied housing units (U.S. Census 

Bureau, 2002). 

public use and losses Municipal water 

other than residential, commercial, or industrial sales that includes such uses as firefighting, pipeline flushing, operational and 

maintenance needs, conveyance losses and 

apparent losses caused by cumulative meter 

misregistration.

water use The terms water use, water 

demand, and water requirement are commonly interchanged. Technically, the terms 

are distinct. In a restrictive sense, water 

use refers to water that is actually used for 

a specific purpose such as for residential 

use or industrial processing. More broadly, 

water use pertains to human interaction with 

and influence on the hydrologic cycle, and 

includes elements such as water withdrawal, 

delivery, consumptive use, wastewater 

release, reclaimed wastewater, return flow, 

and instream use. Water demand is the relation between water use and price when all 

other factors are held constant; however, for 

this study, the relation is between water use 

and climate with all other factors being held 

constant. Water requirement is water use as an 

absolute requirement unaffected by economic 

or climatic factors. 

weather The condition of atmospheric elements such as temperature and precipitation 

at a given time and for a specific area. Many 

observations of the weather of a place over 

a period of years provide us with a description of climate. Climate describes an area’s 

average weather, but it also includes those 

common deviations from the norm or average 

that are likely to occur, as well as extreme 

conditions, such as drought. (Gabler and others, 1990). Weather is not the same as climate. 

Glossary

Hutson—Estimated Use of Water in the Upper Duck River Watershed, Central Tennessee—Scientific Investigations Report 2008-5058