Suspended Sediment and Bed Load in Three Tributaries

to Lake Emory in the Upper Little Tennessee River Basin,

North Carolina, 2000 – 02 

U.S. Geological Survey

U.S. Department of the Interior

Prepared in cooperation with Macon County, North Carolina

U.S. Geological Survey 

Water-Resources Investigations Report 03–4194
U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 03–4194

Suspended Sediment and Bed Load in

Three Tributaries to Lake Emory in the

Upper Little Tennessee River Basin,

North Carolina, 2000–02

Prepared in cooperation with 

Macon County, North Carolina 

By Carolyn J. Oblinger

Raleigh, North Carolina

2003
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

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

from:

U.S. Geological Survey

Branch of Information Services

Box 25286, Federal Center

Denver, CO 80225

1-888-ASK-USGS

The use of firm, trade, and brand names in this report is for identification purposes 

only and does not constitute endorsement by the U.S. Government.

Additional information about U.S. Geological Survey programs and products in 

North Carolina can be obtained from the Web site: http://nc.water.usgs.gov

District Chief

U.S. Geological Survey

3916 Sunset Ridge Road

Raleigh, NC 27607

dc_nc@usgs.gov
Contents III

CONTENTS

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

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

Purpose and scope ...................................................................................................................................................... 3

Study area ................................................................................................................................................................... 3

Acknowledgments ...................................................................................................................................................... 3

Data-collection methods ....................................................................................................................................................... 4

Streamflow data .......................................................................................................................................................... 5

Suspended-sediment data ........................................................................................................................................... 6

Bed-load data ............................................................................................................................................................. 6

Particle size ................................................................................................................................................................ 6

Streamflow ........................................................................................................................................................................... 6

Estimation of streamflow in the Cullasaja River ........................................................................................................ 9

Estimation of Porter’s Bend dam releases .................................................................................................................. 13

Suspended sediment ............................................................................................................................................................. 13

Load ............................................................................................................................................................................ 13

Particle size ................................................................................................................................................................ 19

Bed material ......................................................................................................................................................................... 21

Bed load ..................................................................................................................................................................... 21

Particle size ................................................................................................................................................................ 23

Summary .............................................................................................................................................................................. 23

References ............................................................................................................................................................................ 24

FIGURES

1–2. Maps showing:

1. Location of the upper Little Tennessee River basin, North Carolina .............................................................. 2

2. Locations of streamgages and sediment-sampling sites in the upper Little Tennessee 

River basin, North Carolina ............................................................................................................................ 4

3. Photograph of a Helley-Smith bed-load sampler .................................................................................................... 6

4–13. Graphs showing:

4. Total annual precipitation at the Franklin, North Carolina, Weather Station for 

1990–2001, and the long-term average annual rainfall .................................................................................. 7

5. Long-term minimum and median daily-mean streamflow and daily-mean streamflow for

water year 2001 at (A) the Little Tennessee River near Prentiss and 

(B) Cartoogechaye Creek near Franklin, North Carolina ............................................................................... 7

6. Departure from mean-monthly streamflow at (A) the Little Tennessee River near 

Prentiss and (B) Cartoogechaye Creek near Franklin, North Carolina, and 

(C) monthly rainfall at the Franklin Weather Station ..................................................................................... 8

7. Distributions of sampled streamflows at (A) the Little Tennessee River and 

(B) Cartoogechaye Creek in relation to long-term streamflow durations 

from streamgages at the Little Tennessee River near Prentiss 

and Cartoogechaye Creek near Franklin, North Carolina ............................................................................... 9

8. Relation of daily-mean streamflow in the Cullasaja River to daily-mean streamflows at 

Cartoogechaye Creek near Franklin and the Little Tennessee River near 

Prentiss, North Carolina, for water years 1970–71 ........................................................................................ 10
IV Contents

9. Relation of instantaneous and daily-mean streamflows at the Cullasaja River near 

Franklin, North Carolina, to instantaneous (2001–02) and daily-mean (1970–71) 

streamflows at the Little Tennessee River near Prentiss and 

Cartoogechaye Creek near Franklin ................................................................................................................ 12

10. Distribution of suspended-sediment concentrations at the four Little Tennessee River 

basin study sites in North Carolina .................................................................................................................. 16

11. Relation of daily sediment load to instantaneous streamflow at (A) the Cullasaja River 

near Franklin, (B) Cartoogechaye Creek near Franklin, and (C) the Little Tennessee River 

at Riverside, North Carolina............................................................................................................................. 17

12. Relation of daily suspended-sediment load and instantaneous streamflow at 

Cartoogechaye Creek near Franklin, North Carolina, for 1977–79 and 2001 ................................................ 19

13. Distribution of percentages of suspended-sediment particles finer than 0.062 millimeter 

at the four Little Tennessee River basin study sites in North Carolina ........................................................... 21

TABLES

1. Selected U.S. Geological Survey streamgaging stations in the upper Little 

Tennessee River basin, North Carolina ................................................................................................................... 5

2. Regression equations relating streamflow at the two Little Tennessee River basin index 

sites to streamflow in the Cullasaja River, North Carolina ..................................................................................... 11

3. Relation of streamflow measured at the Cullasaja River to streamflow at Cartoogechaye 

Creek near Franklin and the Little Tennessee River near Prentiss, North Carolina, 

during water years 2001 and 2002 .......................................................................................................................... 11

4. Streamflow statistics for the Little Tennessee River basin, North Carolina, study sites 

for the 2001 water year ........................................................................................................................................... 13

5. Suspended-sediment concentrations at the four Little Tennessee River basin 

study sites in North Carolina and measured or estimated streamflow at 

three of the study sites.............................................................................................................................................. 14

6. Results of regression analyses relating the natural log of instantaneous suspendedsediment load to the natural log of instantaneous streamflow at three Little Tennessee 

River basin study sites in North Carolina ................................................................................................................ 18

7. Estimated suspended-sediment loads and yields at the three study sites and at 

sites sampled in 1970–79 in the Little Tennessee River basin, North Carolina ..................................................... 18

8. Streamflow and suspended-sediment concentration and particle-size distributions 

in samples from the four Little Tennessee River basin study sites in North Carolina ............................................ 20

9. Bed load and suspended-sediment load during three runoff events at three sites in 

the Little Tennessee River basin in North Carolina ................................................................................................ 22

10. Particle-size distribution in bed-load samples from three sites in the Little Tennessee 

River basin in North Carolina ................................................................................................................................. 23
Contents V

CONVERSION FACTORS, ABBREVIATIONS, and ACRONYMS

Abbreviated water-quality units: mg/L, milligram per liter

L, liter (a unit of volume equal to approximately 1.056 quarts)

Acronyms:

EWI equal-width integrated

FISP Federal Interagency Sedimentation Project

MEWI multiple equal-width increment

NOAA National Oceanic and Atmospheric Administration

NWIS National Water Information System

USGS U.S. Geological Survey

VA visual accumulation

GLOSSARY

Daily-mean streamflow—The mean streamflow for any one day. For example, the daily-mean streamflow 

for October 10, 2002.

Annual-mean streamflow—The arithmetic mean of the daily-mean streamflows for the year noted or for 

the designated period. For example, the annual-mean streamflow for 1944 to 2001 is the arithmetic mean of 

all daily-mean streamflow for that period.

Mean-monthly streamflow—The arithmetic mean of the means of record for a specific month during a 

specific period of years. For example, the mean-monthly streamflow for October is the arithmetic mean of all 

October means during 1944 to 2001.

Multiply By To obtain

Length

millimeter (mm) 0.03937 inch

centimeter (cm) 0.3937 inch

meter (m) 3.281 foot

1.094 yard

kilometer (km) 0.6214 mile

Area

hectare (ha) 2.471 acre

square kilometer (km2) 0.3861 square mile

Volume

cubic meter (m3) 35.31 cubic foot

1.308 cubic yard

Flow

meter per second (m/s) 3.281 foot per second

cubic meter per second (m3/s) 35.31 cubic foot per second

cubic meter per second per square kilometer [(m3/s)/km2] 91.49 cubic foot per second per square mile

Mass

kilogram (kg) 2.205 pound

metric ton (t) 1.102 short ton (2,000 pounds)

metric ton per day (t/d) 1.102 short ton (2,000 pounds)

metric ton per square kilometer (t/km2) 2.855 short ton (2,000 pounds) per square mile
Abstract 1

Suspended Sediment and Bed Load in Three Tributaries 

to Lake Emory in the Upper Little Tennessee River Basin, 

North Carolina, 2000–02

By Carolyn J. Oblinger

ABSTRACT

A study was conducted in the upper Little 

Tennessee River basin to characterize suspendedsediment and bed-load sediment transport into Lake 

Emory from the main stem and two major 

tributaries—Cartoogechaye Creek and the Cullasaja 

River. Suspended-sediment concentrations in the 

discharge from Lake Emory also were measured. 

Weekly samples for suspended-sediment concentration 

were collected between November 2000 and November 

2001, and periodic samples were collected during 

targeted high-flow events. Suspended-sediment 

samples were collected during stormwater runoff 

conditions for analysis of particle-size distribution. 

Three bed-load samples were collected at each stream 

site.

The greatest annual load (5,700 metric tons) and 

yield (18 metric tons per square kilometer) of 

suspended sediment during the study period were in the 

Little Tennessee River near Riverside, North Carolina. 

Much smaller annual yields were calculated for Lake 

Emory, the Cullasaja River, and Cartoogechaye Creek 

(5, 5, and 7 metric tons per square kilometer, 

respectively). Drought conditions during the study 

period appear to have been a factor in the small loads 

compared to loads measured in the same area in the 

1970’s. The annual-mean streamflow at the Little 

Tennessee River at Prentiss during 2001 was about 

50 percent of the long-term annual-mean streamflow 

(1944–2001). High-flow events carry most of the 

annual sediment load.

INTRODUCTION

The upper Little Tennessee River basin in 

western North Carolina is part of the Little Tennessee 

River basin upstream from Fontana Lake (fig. 1). The 

upper basin is mountainous and rural—less than 

5 percent of the land use in the basin is classified as 

urban and 89 percent is forested. Parts of the basin lie 

within the Great Smoky Mountains National Park and 

Nantahala National Forest. Because the Little 

Tennessee River is a mountain river, its tributaries 

typically have relatively steep gradients and riffle 

habitats capable of supporting trout populations (North 

Carolina Division of Water Quality, 2000). The Little 

Tennessee River also supports a large variety of other 

aquatic species, including three rare species on the 

Federal endangered species list—the Appalachian 

elktoe mussel (Alasmidonta raveneliana), the littlewing pearly mussel (Pegias fabula), and the Spotfin 

chub (Cyprinella monacha). The Little Tennessee 

River basin is the only basin in North Carolina where 

the slippershell mussel (Alasmidonta viridis) and 

Tennessee pigtoe mussel (Fusconaia barnesiana) can 

be found.

A major water-quality issue in the rural setting of 

the Little Tennessee River basin is sedimentation—

both historic and recent (North Carolina Division of 

Water Quality, 2002). Sedimentation is the primary 

factor affecting ecological communities in the basin 

(Harding and others, 1998), resulting in loss of instream microhabitats and aquatic-habitat degradation. 

Sedimentation is caused primarily by land-clearing 
2 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 1. Location of the upper Little Tennessee River basin, North Carolina.
Introduction 3

activities, rural roads, loss of riparian vegetation to 

agriculture and silviculture, and urban runoff. In 

addition, landscape features, such as high streamchannel gradients, are important factors contributing to 

sedimentation rates (Scott and others, 2002). Harding 

and others (1998) reported that the conditions of 

current aquatic communities are related more to past 

land use than to current land use. 

Historically, sediment has clogged the channel of 

the upper Little Tennessee River and has deposited 

sediment in Lake Emory (fig. 1; North Carolina 

Department of Environment, Health, and Natural 

Resources, 1992, p. 155). Riparian agricultural 

practices, such as stock watering and growing specialty 

vegetable crops, and more recently, increasing 

urbanization in the upper portion of the watershed in 

the towns of Highlands and Franklin have increased the 

river's suspended-sediment load and bed load. Thus, by 

trapping sediments, Lake Emory has protected 

important natural resources downstream, particularly 

in respect to several federally listed species of 

freshwater mussel.

Suspended-sediment data are available from the 

1970's for the Little Tennessee River at Needmore and 

Cartoogechaye Creek near Franklin (Simmons, 1993). 

Average annual suspended-sediment loads were 

calculated to be 100,000 metric tons (t) for the Little 

Tennessee River at Needmore and 10,000 t for 

Cartoogechaye Creek near Franklin for the 1970’s. 

Average annual suspended-sediment yields at these 

sites were 110 and 81 metric tons per square kilometer 

(t/km2

), respectively. By comparison, an average yield 

of 68 t/km2 was calculated for rural, agricultural sites in 

the upper Tennessee River basin (Simmons, 1993). 

Federal, State, and local agencies and 

organizations are working to restore degraded aquatic 

resources in the upper Little Tennessee River and some 

of its tributaries, including protection and enhancement 

of threatened and endangered species populations and 

wetland restoration. Key to developing restoration 

strategies is a better understanding of the amount of 

sediment that is transported in the upper Little 

Tennessee River, the sediment sources and particle-size 

characteristics, and the amount of sediment that is 

transported past Porter's Bend dam at Lake Emory. The 

data collected during this investigation begin to address 

these issues.

Purpose and Scope

This report describes the results of a study to 

characterize suspended-sediment and bed-load 

sediment transport into Lake Emory from the main 

stem of the Little Tennessee River and two major 

tributaries—Cartoogechaye Creek and the Cullasaja 

River. Suspended-sediment concentration in discharge 

from Lake Emory also was measured. Sediment 

samples were collected weekly over a 12-month period 

from November 2000 to November 2001. In addition, 

three bed-load measurements were made between 

October 2001 and September 2002. 

Study Area

The Little Tennessee River basin is in the Blue 

Ridge Physiographic Province. The river rises in 

Georgia near the North Carolina border and flows north 

through North Carolina into Tennessee (fig. 1) where it 

joins the Tennessee River. The upper Little Tennessee 

River basin is the area of the Little Tennessee River 

basin that is upstream from Fontana Lake. The study 

area includes the portion of the upper Tennessee River 

basin upstream from Porter's Bend dam at Lake Emory 

(fig. 2). The study area is drained by the Little 

Tennessee River, the Cullasaja River, and 

Cartoogechaye Creek. The Cullasaja River and 

Cartoogechaye Creek join the Little Tennessee River 

near Franklin, N.C. (fig. 2). 

 Lake Emory is a 76-hectare (ha) reservoir built 

in the 1920's as a source of hydropower. Nantahala 

Power and Light Company has owned and operated the 

lake since 1933 (North Carolina Department of 

Environment, Health, and Natural Resources, 1992). 

Based on lake samples collected in July 1988, the lake 

has been described as eutrophic and shallow and having 

a short retention time (North Carolina Department of 

Environment, Health, and Natural Resources, 1992). 

Suspended-solids concentrations at each of three sites 

sampled in the lake were at least 18 milligrams per liter 

(mg/L).

Acknowledgments

This investigation was cooperatively funded by 

the U.S. Geological Survey (USGS) and Macon 

County, N.C. The author wishes to thank Eugene 

Gonzales of Macon County for collecting weekly 
4 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 2. Locations of streamgages and sediment-sampling sites in the upper Little Tennessee River 

basin, North Carolina.

suspended-sediment samples regardless of weather 

conditions. The author also wishes to acknowledge the 

assistance of Gene Barker and his staff from the USGS 

Field Office in Asheville, N.C. Leadership in bringing 

together the partners who supported this investigation 

was provided by Linda Adcock of the U.S. Army Corps 

of Engineers in Nashville, Tenn.

DATA-COLLECTION METHODS

The data-collection methods used during this 

investigation are consistent with published USGS 

protocols (Rantz and others, 1982; U.S. Geological 

Survey, 1997–present; Edwards and Glysson, 1999). 

Results of all sediment analyses are stored in the USGS 
Data-Collection Methods 5

National Water Information System (NWIS) waterquality database.

Streamflow Data

Streamflow in the upper Little Tennessee River 

basin was determined from measurements from 

available streamgage records (Rantz and others, 1982) 

or from estimates based on record from a nearby 

streamgage. The streamgages in the study area are 

operated and maintained by the USGS in cooperation 

with the North Carolina Department of Environment 

and Natural Resources. 

Of the four study sites (table 1), streamflow is 

recorded continuously only at Cartoogechaye Creek 

near Franklin. Streamflow at the Little Tennessee River 

at Riverside was estimated from streamflow record at 

the Little Tennessee River near Prentiss, about 

4.8 kilometers (km) downstream. Streamflow near 

Prentiss was reduced by multiplying by a factor 

determined by the ratio of the drainage areas 

(311 km2 / 363 km2 = 0.857) to obtain an estimate of 

the streamflow at Riverside.

Estimating the streamflow at Cullasaja River 

near Franklin was more complex, however, because no 

streamgage was in operation on the Cullasaja River 

during the study period. A location just upstream from 

the Cullasaja study site was operated from 1921 to 

1971—Cullasaja River at Cullasaja, N.C. (03501000). 

Although the difference in the drainage areas of the two 

sites is only 12 km2

, a stage-streamflow relation from 

this gage was too dated to be useful. In addition, a 

60-ha drinking-water reservoir, Lake Sequoyah, 

impounds the upper 23 km2

 of the watershed and 

potentially affects streamflow downstream (fig. 1). 

As a result, two nearby streamgages were 

selected as potential index sites for estimating 

streamflow at the Cullasaja River near Franklin—the 

Little Tennessee River near Prentiss (03500000) and 

Cartoogechaye Creek near Franklin (03500240). 

Historic streamflow records were retrieved from the 

NWIS surface-water database and analyzed to 

determine which of the two sites was the better index 

site. 

Discharge below the dam at Lake Emory also 

had to be estimated. Although water is released through 

the turbines at the Porter's Bend dam for power 

generation, no records of the releases are maintained by 

Nantahala Power and Light Company (Richard Conley, 

Duke Power Lake Management, oral commun., 

December 20, 2001). In addition, leakage occurs 

through the dam structure, and when lake levels are 

high, water also may be released over the spillway. An 

annual-mean streamflow was estimated for 2001 based 

Table 1. Selected U.S. Geological Survey streamgaging stations in the upper Little Tennessee River basin, North Carolina

[USGS, U.S. Geological Survey; km2, square kilometer; m3/s, cubic meter per second; t, metric ton; t/km2, metric ton per square kilometer; bold/shaded 

station numbers and names identify sites sampled for this study; —, no data]

USGS station 

numbera

(fig. 2)

a

 Station number is assigned by the U.S. Geological Survey on the basis of geographic location. The downstream order number system is used for 

surface-water sites.

Station name

Period of 

streamflow 

record 

(water yearsb)

b

 Water year is the period October 1 through September 30 and is identified by the year in which the period ends.

Drainage

area

(km2

)

Annual-mean streamflow 

(m3

/s)

Annual suspended 

sediment

Period of 

record

2001 water 

year

Load 

(t)

Yield 

(t/km2

)

0349998425 Little Tennessee River at Riverside — 311 — — — —

03500000 Little Tennessee River near Prentiss 1943 – present 363 11 5.44 — —

03500240 Cartoogechaye Creek near Franklin 1944, 1947, 

1953 – 55, 

1958, 1960, 

1961 – present

148 4.1 2.09 10,000 81

0350116510 Cullasaja River near Franklin — 236 — — — —

03501000 Cullasaja River at Cullasaja 1907 – 09, 

1921 – 71

224 — — — —

03501564 Lake Emory at the dam near Franklin — 804 — — — —

03503000 Little Tennessee River at Needmore 1943 – 81, 

1983 – present

1,130 29.9 15.2 100,000 110
6 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 3. Helley-Smith bed-load sampler.

on record from the streamgage at the Little Tennessee 

River at Needmore about 32 km below the dam (fig. 1).

Suspended-Sediment Data

Stream samples for analysis of suspendedsediment concentration were collected once per week at 

each of the four study sites. In addition, several samples 

were collected during targeted high-flow events. At 

each data-collection stream site, a box enclosure 

containing a US-D-74 suspended-sediment sampler 

was mounted to a bridge rail at the approximate center 

of streamflow (Edwards and Glysson, 1999). Macon 

County staff used this equipment to collect single, 

vertical, suspended-sediment samples (box samples) 

once per week. The US-D-74 sampler is one of a 

number of samplers designed by the Federal 

Interagency Sedimentation Project (FISP) for use in 

collecting a depth-integrated suspended-sediment 

sample. USGS staff used a US-DH-81 or US-DH-59 

sampler periodically to collect equal-width integrated 

(EWI) suspended-sediment samples that could be used 

to validate the single, vertical samples as being 

representative of the average suspended-sediment 

concentration in the stream cross section. Suspendedsediment concentrations in samples collected using the 

EWI method were compared to concentrations 

measured in the box samples. The samples were 

shipped to the USGS sediment laboratory in Louisville, 

Ky., and analyzed for suspended-sediment 

concentration. Samples were analyzed by using the 

filtration method described by Guy (1977). 

Bed-Load Data

A Helley-Smith type sampler was used to sample 

bed load (fig. 3). The sampler is designed to collect 

particles less than 76 millimeters (mm) at mean 

velocities up to 3.0 meters per second (m/s). The 

sampler has a 76-mm by 76-mm opening to a 0.25-mm 

mesh sampling bag that is supported by a metal frame. 

The sampler weighs 29.9 kilograms (kg). The nozzleexpansion ratio is 3.1.

Bed-load samples were analyzed for total weight 

by the USGS sediment laboratory in Iowa City, Iowa, 

using methods described by Guy (1977). Two samples 

were collected from each stream site using the multiple 

equal-width-increment (MEWI) method (Edwards and 

Glysson, 1999, p. 75). Each stream cross section was 

sampled at five equally spaced locations. The sampler 

was positioned on the streambed at each location for 

20 minutes in October 2001 when streamflow was low, 

and for 5 minutes in January and September 2002 when 

streamflow was much greater. Two transects were 

collected for a total of 10 subsamples for each sample. 

Subsamples were combined into one composite sample 

that was analyzed for total weight and particle-size 

distribution. The number of subsections, width of each 

subsection, time the sampler rested on the streambed, 

number of transects, and average streamflow during the 

sampling period were recorded.

Particle Size

Selected suspended-sediment samples were 

analyzed for the distribution of particle sizes. The 

quantity of material collected was, for most samples, 

insufficient for a full particle-size analysis. Therefore, 

samples were sieved according to Guy (1977) to 

determine the percentage of particles finer than 

sand—less than (<) 0.062 mm. However, at least one 

suspended-sediment sample from each stream site was 

analyzed for a more complete range of particle sizes by 

using the visual accumulation (VA) tube method (Guy, 

1977). Each bed-load sample was analyzed for particlesize distribution by the USGS sediment laboratory in 

Iowa City using methods described by Guy (1977).

STREAMFLOW

A severe drought was occurring in western North 

Carolina during the study period. Rainfall at the 

National Oceanic and Atmospheric Administration’s 
Streamflow 7

Figure 5. Long-term minimum and median daily-mean streamflow and daily-mean streamflow for water year 2001 at 

(A) the Little Tennessee River near Prentiss and (B) Cartoogechaye Creek near Franklin, North Carolina.

Figure 4. Total annual precipitation at the Franklin, North Carolina, Weather 

Station for 1990 – 2001, and the long-term average annual rainfall.

(NOAA) Franklin, N.C., weather station 

typically averages 134 centimeters (cm) per 

year based on data collected from 1949 through 

2000 (Southeast Regional Climate Center, 

2003). Rainfall amounts at the Franklin weather 

station are seasonally variable but declined 

steadily overall from about July 1998 (fig. 4). 

Ninety percent of the daily-mean streamflows 

in 2001 were less than the median daily-mean 

streamflow at the Little Tennessee River near 

Prentiss and Cartoogechaye Creek near 

Franklin (fig. 5), and the annual-mean streamflow for 2001 was 50 percent of the long-term 

annual-mean streamflow (table 1). Moreover, 

new minimum values for daily-mean streamflow were established for 12 and 18 percent of 

the days in 2001 at the Little Tennessee River 

near Prentiss and Cartoogechaye Creek near 

Franklin, respectively. Monthly departures 

from the long-term mean-monthly streamflows 

were almost entirely negative at these two sites 

beginning in July 1998 (fig. 6).
8 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 6. Departure from mean-monthly streamflow at (A) the Little Tennessee River near 

Prentiss and (B) Cartoogechaye Creek near Franklin, North Carolina, and (C) monthly rainfall at 

the Franklin Weather Station.

Because streamflows generally were very low 

during the period of study, few of the sampled 

streamflows represent high-flow conditions. This is 

important to note because most suspended sediment is 

transported under high-flow conditions. In figure 7, the 

distributions of sampled streamflows at Cartoogechaye 

Creek and the Little Tennessee River are shown in 

relation to long-term streamflow durations from 

streamgages at Cartoogechaye Creek near Franklin and 

the Little Tennessee River near Prentiss. At both sites, 

75 percent of the suspended-sediment samples were 

collected at streamflows that were approximately equal 

to the long-term 70th to 75th percentile streamflow 

duration. That is, most of the samples were collected at 

streamflows that, when compared to long-term 

streamflow record, are equaled or exceeded 70 to 

75 percent of the time. However, the maximum 

streamflow sampled at Cartoogechaye Creek was quite 

high—near the long-term 1st percentile streamflow 

duration (fig. 7B). Likewise, the maximum streamflow 

sampled at the Little Tennessee River was between the 

long-term 15th and 20th percentile streamflow duration 

(fig. 7A). Suspended-sediment concentrations 

collected during these high streamflow events are 

crucial to adequately define the relation between 

streamflow and sediment concentration.
Streamflow 9

Figure 7. Distributions of sampled streamflows at (A) the Little Tennessee River and 

(B) Cartoogechaye Creek in relation to long-term streamflow durations from streamgages at 

the Little Tennessee River near Prentiss and Cartoogechaye Creek near Franklin, North 

Carolina.

Estimation of Streamflow in the Cullasaja River

Record from a discontinued streamgage at 

Cullasaja River at Cullasaja, which has a drainage area 

12 km2

 less than the drainage area near Franklin 

(table 1), provided daily-mean streamflow that was 

compared to coincidental daily-mean streamflow at 

streamgages at Cartoogechaye Creek near Franklin and 

the Little Tennessee River near Prentiss to assess 

whether either of these streamgages could be used as an 

index gage. An index gage was needed to estimate 

streamflow during the study period for the Cullasaja 

River near Franklin. The most recent year for which 

coincident daily-mean streamflow data were available 

for these three sites was water year1 1971. Streamflow 

was compared for water years 1970–71 (fig. 8). 

Equations relating daily-mean streamflow at the index 

sites to daily-mean streamflow at the Cullasaja River at 

Cullasaja were determined by means of ordinary leastsquares linear regression (table 2). The greater scatter 

about the regression line and the lower coefficient of 

determination (R2

) for Cartoogechaye Creek near 

1

 Water year is the period October 1 through September 30 and is 

identified by the year in which the period ends.
10 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 8. Relation of daily-mean streamflow in the Cullasaja River to daily-mean streamflows at 

Cartoogechaye Creek near Franklin and the Little Tennessee River near Prentiss, North Carolina, for 

water years 1970 – 71.
Streamflow 11

Franklin indicate that Cartoogechaye Creek is a poorer 

index gage for the Cullasaja River than is the Little 

Tennessee River near Prentiss.

During the study, instantaneous streamflow was 

measured seven times at the Cullasaja River near 

Franklin at streamflows ranging from 1.77 to 21.0 

cubic meters per second (m3/s; table 3). These 

instantaneous streamflow measurements were 

compared to simultaneous instantaneous streamflow 

determined from the streamgage record at the potential 

index sites (table 3; fig. 9). Instantaneous streamflows 

at the index sites were related to instantaneous 

streamflow at the Cullasaja River near Franklin using 

ordinary least-squares linear regression (table 2). 

As in the 1970–71 relations (fig. 8; table 2), the 

greater scatter about the regression line and the lower 

R2 value for Cartoogechaye Creek near Franklin 

indicate that Cartoogechaye Creek is a poorer index 

gage for the Cullasaja River than is the Little Tennessee 

River near Prentiss. The slope and intercept of the 

2001–02 relation for the Little Tennessee River near 

Prentiss are very similar to the slope and intercept of 

the 1970–71 relation. The slight offset of the 2001–02 

regression relation compared with the 1970–71 

relation is due, in part, to the difference in the drainage 

areas of the Cullasaja River at Cullasaja (1970–71 

relation) and the Cullasaja River near Franklin 

(2001–02 relation; table 1). For example, when 

Table 2. Regression equations relating streamflow at the two Little Tennessee River basin index 

sites to streamflow in the Cullasaja River, North Carolina

[N, number of observations; R 2, coefficient of determination; P value, probability that the slope is equal to zero; 

Qcc, streamflow, in meters per second, at the Cullasaja River at Cullasaja; Qcf, streamflow, in meters per second, 

at the Cullasaja River near Franklin; InQi

, natural log of streamflow, in meters per second, at the index gage]

Type of streamflow record N Regression equation R 2 P value for 

the slope

Little Tennessee River near Prentiss

Daily mean, 1970 – 71 730 Qcc = e0.98(InQi)–0.46 0.9242 0.0000

Instantaneous, 2001 – 02 7 Qcf = e1.014(InQi)–0.45 0.9886 0.0000

Cartoogechaye Creek near Franklin

Daily mean, 1970 – 71 730 Qcc = e0.85(InQi)–0.70 0.8159 0.0000

Instantaneous, 2001 – 02 7 Qcf = e0.83(InQi)–0.75 0.8834 0.0016

Table 3. Relation of streamflow measured at the Cullasaja River to streamflow at Cartoogechaye Creek 

near Franklin and the Little Tennessee River near Prentiss, North Carolina, during water years 2001 and 2002

[Water year is the period October 1 through September 30 and is identified by the year in which the period ends; %, percent]

Date Time

Instantaneous streamflow, 

in cubic meters per second

Predicted streamflow at Cullasaja River 

based on comparison of data for the study 

period with data from the index gage 

(percent error)

Cartoogechaye 

Creek

Little 

Tennessee 

River near 

Prentiss

Cullasaja 

River

Cartoogechaye 

Creek

Little Tennessee 

River near 

Prentiss

03-14-2001 1030 3.20 9.03 6.00 5.56 (7%) 5.48 (9%)

05-02-2001 1050 1.90 5.12 3.88 3.60 (7%) 3.73 (4%)

06-22-2001 1220 1.13 3.06 1.77 2.35 (-33%) 1.97 (-11%)

08-31-2001 1030 1.05 3.06 1.86 2.20 (-18%) 2.19 (-18%)

09-25-2001 1130 2.32 12.32 7.70 4.26 (45%) 8.05 (-5%)

10-25-2001 1055 2.07 4.62 3.31 3.65 (-10%) 3.03 (9%)

01-23-2002 1523 19.7 32.0 21.0 25.1 (-20%) 21.1 (-1%)
12 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 9. Relation of instantaneous and daily-mean streamflows at the Cullasaja River near Franklin, 

North Carolina, to instantaneous (2001 – 02) and daily-mean (1970 – 71) streamflows at the Little 

Tennessee River near Prentiss and Cartoogechaye Creek near Franklin.

streamflow at the Little Tennessee River near Prentiss 

is 10 m3/s, the calculated streamflow using the relation 

for 2001–02 data from the Cullasaja River near 

Franklin is 6.52 m3/s, whereas the calculated 

streamflow using the relation for 1970–71 data from 

the Cullasaja River at Cullasaja is 6.03 m3

/s (fig. 9). 

When divided by the drainage area, the resulting runoff 

values are nearly the same—0.028 and 0.027 cubic 

meter per second per square kilometer [(m3

/s)/km2] 

near Franklin and at Cullasaja, respectively.

The Little Tennessee River near Prentiss was 

selected as the best index site for estimating streamflow 

at the Cullasaja River near Franklin based on the better 

closeness of fit (table 3) and higher coefficient of 

determination (92 to 98 percent, table 2) for the 

regression equation compared with the equation for the 

other potential index site. The equation based on 

2001–02 data was selected even though it was based on 

only seven measurements, because the data were more 

current and the relation was verified by the large 

amount of data collected during 1970–71.
Suspended Sediment 13

Estimation of Porter’s Bend Dam Releases

No records exist of releases through the Porter’s 

Bend dam at Lake Emory, so the quantity of water 

discharged from the lake had to be estimated in order to 

estimate sediment load from the lake. Two methods 

were used to estimate an annual-mean water discharge 

from the dam. In the first method, streamflows in the 

Little Tennessee River near Prentiss, Cartoogechaye 

Creek near Franklin, and the Cullasaja River near 

Franklin were measured or estimated at 15-minute 

intervals for the study period, and the values were 

summed. The result was 396,800,000 m3 of streamflow 

for the study period (1.25 years), or an annual-mean 

streamflow of 10.0 m3

/s, which was the assumed 

discharge through the dam. In the second method, the 

measured annual-mean streamflow at the Little 

Tennessee River at Needmore for 2001 (15.3 m3/s, 

table 4) was reduced by multiplying by a factor 

determined by the ratio of drainage areas 

(804 / 1,130 = 0.71) to estimate an annual-mean 

streamflow of 11 m3/s, which was the assumed 

discharge through Porter’s Bend dam. 

Using the two estimated values, the annual 

runoff, in centimeters, was calculated and compared 

with annual runoff at the other sites (table 4). The 

estimated annual runoff for the dam obtained by using 

the second method was reasonably close to runoff at 

other sites in the study area, so the annual-mean 

streamflow of 11 m3/s was judged to be a reasonable 

estimate for calculating suspended-sediment load.

SUSPENDED SEDIMENT

Samples for analysis of suspended-sediment 

concentration were collected once per week at each site 

from November 2000 to November 2001 (table 5). In 

addition, several samples were collected during 

targeted high-flow events. The distribution of measured 

concentrations at each site is shown in figure 10. The 

greatest median suspended-sediment concentration was 

measured at Porter’s Bend dam at Lake Emory 

(12 mg/L). Lowest median concentrations were 

measured at the Cullasaja and Cartoogechaye sites 

(5 and 4.9 mg/L, respectively), although the range of 

concentrations was large. 

Load

Instantaneous suspended-sediment loads, in 

metric tons per day, were calculated from instantaneous 

streamflow and measured suspended-sediment 

concentration. A regression equation was developed for 

each site—the Little Tennessee River at Riverside, 

Cartoogechaye Creek, and the Cullasaja River—

relating the natural log of streamflow to the natural log 

of suspended-sediment load at each site (fig. 11; 

table 6). The regression equations were used to 

calculate suspended-sediment loads for each 15-minute 

(unit value) interval at each site by using continuous 

streamflow record (Cartoogechaye Creek and the Little 

Tennessee River at Riverside) or estimates of 

streamflow (Cullasaja River). These unit-value load 

data were summed for each site. Each sum was adjusted 

by multiplying by the mean of the antilog of the 

regression residuals (Duan's smearing estimator) to 

account for retransformation bias (Duan, 1983; Koltun 

and others, 1994) to determine the total load for the 

study period (1.25 years). The total load for the period 

of study, annual load, and annual yield are shown in 

table 7.

As noted previously, suspended-sediment load 

could not be calculated for water discharged from Lake 

Emory because there was no record of streamflow out 

of the dam. Instead, suspended-sediment load was 

estimated by using the 11-m3

/s estimate for average 

Table 4. Streamflow statistics for the Little Tennessee River 

basin, North Carolina, study sites for the 2001 water year

[Water year is the period October 1 through September 30 and is identified 

by the year in which the period ends; km2, square kilometer; m3/s, cubic 

meter per second; cm, centimeter]

Site

Drainage 

area, 

in km2

Annual-mean 

streamflow, 

in m3

/s

Runoff, 

in cm

Little Tennessee River at 

Riverside

311 4.58 46.4

Little Tennessee River at 

Needmore

1,130 15.3 42.7

Cartoogechaye Creek 

near Franklin

148 2.09 44.5

Cullasaja River near 

Franklin

236 3.4 45.4

Porter’s Bend dam at 

Lake Emory

804 a

10 / b11

a

 Estimated annual-mean streamflow by using method one. b Estimated annual-mean streamflow by using method two.

c

39 / d43

c

 Calculated runoff by using estimated annual-mean streamflow from 

method one. d Calculated runoff by using estimated annual-mean streamflow from 

method two.
14 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Table 5. Suspended-sediment concentrations at the four Little Tennessee River basin study sites in North Carolina and measured or estimated sstudy sites[m3/s, cubic meter per second; mg/L, milligram per liter; bold values represent the average of multiple vertical samples; —, no data]

Little Tennessee River at Riverside Cartoogechaye Creek near Franklin Cullasaja River near Franklin 

Date Time

aInstantaneous 

streamflow, 

in m3/s

Suspendedsediment 

concentration, 

in mg/L

Time

Instantaneous 

streamflow, 

in m3/s

Suspendedsediment 

concentration, 

in mg/L

Time

aInstantaneous 

streamflow, 

in m3/s

Suspend

sedime

concentr

in mg

06–21–2000 1440 4.0 17 1240 1.5 14 1540 3.03 17 11–14–2000 1215 2.6 4.5 1105 1.0 3.0 1404 1.90 3.3 11–14–2000 1230 2.6 3.9 1110 1.0 1.5 1420 1.90 4.011–21–2000 1200 2.5 4.9 1100 1.0 7.0 1315 1.90 25 11–27–2000 0925 4.9 7.6 0830 1.8 3.7 1400 3.49 4.5 12–05–2000 1200 2.6 5.2 1100 1.0 2.5 1345 1.93 2.0 12–12–2000 1050 2.3 4.1 1115 1.0 2.3 1220 1.75 .6 12–19–2000 1130 5.7 13 1100 2.7 4.4 1200 4.35 5.3 12–26–2000 1100 3.1 5.4 1000 1.2 .6 1200 2.32 .8 01–02–2001 1100 2.7 7.2 1200 .9 3.0 1215 1.93 5.6 01–09–2001 1306 2.9 5.0 1330 1.0 3.0 1410 2.12 6.4 01–16–2001 1100 2.8 4.1 1130 1.1 3.5

—

—

— 

01–23–2001 1100 7.4 13 1200 3.5 7.2 1300 5.68 4.9 01–30–2001 1115 9.6 72 1145 4.0 25 1230 7.58 16 02–06–2001 1030 4.5 3.0 1100 1.6 3.8 1130 3.40 3.5 02–13–2001 1100 4.7 4.1 1145 1.9 2.6 1245 3.55 .8 02–20–2001 1200 5.9 6.9 1100 3.2 3.3 1245 4.41 4.1 02–26–2001 1100 14.0 97 1020 8.0 23 1145 10.57 19 02–27–2001 1245 10.0 32 1145 5.6 12 1345 7.66 12 03–06–2001 1000 7.1 9.7 1100 3.3 2.8 1200 5.35 2.9 03–13–2001 1000 10.7 56 1100 4.0 12 1200 7.73 6.9 03–20–2001 1000 8.0 24 1100 4.0 9.7 1200 7.17 6.0 03–27–2001 1000 7.4 9.1 1100 3.1 2.7 1200 5.68 3.5 04–03–2001 1000 7.9 12 1100 3.7 6.2 1200 6.02 3.4 04–10–2001 1000 6.1 11 1100 2.6 5.8 1200 4.62 19 04–17–2001 1100 5.5 12 1200 2.9 5.0 1230 4.15 2.9 04–24–2001 1000 4.7 11 1100 2.2 8.0 1200 3.55 6.0 05–01–2001 1000 4.9 13 1100 2.0 7.7 1200 3.68 5.9 05–02–2001 1025 4.4 9.7 1135 1.9 7.0 1335 3.27 2.6 05–02–2001 1110 4.4 7.5 1200 1.9 4.7 1350 3.27 3.205–08–2001 1000 3.9 8.0 1100 1.6 6.0 1000 2.95 5.0 05–15–2001 1100 3.4 7.0 1100 1.4 5.8 1000 2.51 3.0 05–22–2001 0900 3.7 24 1000 1.4 8.0 1100 2.81 9.0 05–29–2001 1100 4.6 26 1200 1.9 10 1300 3.49 12 
Suspended Sediment 15

06–05–2001 1100 3.8 18 1200 1.5 7.1 1300 2.92 8.5 06–12–2001 1100 3.3 13 1200 1.3 6.0 1300 2.55 9.0 06–19–2001 1200 2.6 8.7 1300 1.0 2.5 1400 1.97 4.9 06–26–2001 1200 15.7 554 1300 18.2 933 1400 17.64 75 07–03–2001 1100 5.6 26 1200 2.0 14 1300 4.35 19 07–10–2001 1100 4.1 12 1200 1.4 6.1 1300 3.07 7.1 07–17–2001 1100 2.9 11 1200 1.1 3.6 1300 2.16 2.8 07–24–2001 1100 2.4 17 1200 .9 5.4 1300 1.79 2.0 07–31–2001 1100 5.4 497 1200 1.3 7.8 1300 8.53 9.0 07–31–2001 — — — — — — — — — 08–07–2001 1100 3.5 23 1200 1.2 5.3 1300 2.68 9.4 08–14–2001 1100 7.9 79 1200 2.0 27 1300 5.52 38 08–21–2001 1100 2.7 7.2 1200 1.0 2.5 1300 2.01 3.8 08–28–2001 1100 2.3 7.1 1200 1.0 2.6 1300 1.75 2.3 09–04–2001 1100 4.3 12 1200 1.5 4.2 1300 2.81 9.4 09–11–2001 1200 2.7 5.2 1300 1.0 1.7 1400 1.75 7.5 09–18–2001 1200 2.1 4.2 1300 .9 1.9 1400 1.40 1.4 09–25–2001 1200 12.1 67 1300 2.3 20 1400 7.70 21 09–26–2001 1055 6.5 19 1151 1.6 2.0 1351 4.88 3.0 10–02–2001 1100 4.0 4.0 1200 1.0 1.1 1100 2.55 1.3 10–09–2001 1100 3.5 2.2 1200 1.0 .6 1300 2.27 .8 10–16–2001 1100 5.9 12 1200 1.5 3.5 1300 4.41 8.2 10–23–2001 1100 3.8 4.1 1200 1.2 3.0 1300 2.84 2.9 10–24–2001 1400 3.6 4.0 1500 1.2 1.4 — — — 10–25–2001 — — — — — — 1200 3.31 2.5 10–30–2001 1100 3.5 3.0 1200 1.1 2.2 1300 2.60 3.8 11–06–2001 1100 3.1 1.8 1200 1.1 .8 1300 2.36 1.5 11–13–2001 1100 2.9 2.9 1200 1.0 1.3 1300 2.19 .5 11–20–2001 1100 2.8 2.1 1200 1.0 2.5 1300 2.12 .8 11–27–2001 1100 4.3 6.5 1200 1.5 3.2 1300 3.23 2.8 01–20–2002 1130 13.4 87 — — — 1040 — 9.0 01–23–2002 1325 28.2 369 1110 21.7 324 1215 21.0 114 01–23–2002 1327 28.2 289 1112 21.7 302 1216 — 169 01–24–2002 1421 19.5 47 1015 10.6 5.9 1224 12.4 2.8 

a Estimated from the streamgage record at the Little Tennessee River near Prentiss.

Table 5. Suspended-sediment concentrations at the four Little Tennessee River basin study sites in North Carolina and measured or estimated s

study sites—Continued

[m3/s, cubic meter per second; mg/L, milligram per liter; bold values represent the average of multiple vertical samples; —, no data]

Little Tennessee River at Riverside Cartoogechaye Creek near Franklin Cullasaja River near Franklin 

Date Time

aInstantaneous 

streamflow, 

in m3/s

Suspendedsediment 

concentration, 

in mg/L

Time

Instantaneous 

streamflow, 

in m3/s

Suspendedsediment 

concentration, 

in mg/L

Time

aInstantaneous 

streamflow, 

in m3/s

Suspend

sedime

concentr

in mg
16 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Figure 10. Distribution of suspended-sediment concentrations at the four Little Tennessee River basin study sites in North 

Carolina.
Suspended Sediment 17

Figure 11. Relation of daily sediment load to instantaneous streamflow at (A) the Cullasaja 

River near Franklin, (B) Cartoogechaye Creek near Franklin, and (C) the Little Tennessee 

River at Riverside, North Carolina.
18 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

daily discharge from the dam (table 4) and a median 

measured suspended-sediment concentration of 

12 mg/L (fig. 10). This resulted in an estimated annual 

suspended-sediment load of 4,200 t and yield of 

5 t/km2 (table 7). 

The greatest annual load and yield in 2001 

(5,700 t and 18 t/km2

, respectively) was in the Little 

Tennessee River at Riverside (table 7). The yield at 

Riverside far exceeded the yields at Cartoogechaye 

Creek, the Cullasaja River, and out of Lake Emory. By 

comparison, Simmons (1993) calculated mean-annual 

suspended-sediment yields, based on data from the 

1970's, of 20 t/km2

 for the Nantahala River near 

Rainbow Springs and 15 t/km2

 for Cataloochee Creek 

near Cataloochee—two relatively pristine, forested 

basins in the Blue Ridge Province of North 

Carolina.

In order to assess the significance of 

drought conditions during the study period on 

suspended-sediment loads, the 2001 data were 

compared with estimates of suspendedsediment load and yield, and the annual-mean 

streamflows at Cartoogechaye Creek near 

Franklin and the Little Tennessee River at 

Needmore between 1970 and 1979 (Simmons, 

1993; table 7). Annual load and yield were an 

order of magnitude less during the study period 

compared to estimates from the 1970’s. This 

may be, in part, due to the higher streamflows 

during the period 1970–79 when annual-mean 

streamflows were more than twice as high as those 

during the study period (table 7). 

The decrease in suspended-sediment load 

compared to the 1970’s also may be a result of longterm change in the relation between suspendedsediment load and streamflow as a result of changes in 

land-use conditions in the basin. Annual suspendedsediment loads are highly variable and difficult to 

assess with only 1 year of recent data. The relation of 

suspended-sediment load to instantaneous streamflow 

for the period 1977–79 (when streamflow and 

suspended-sediment data are available) was compared 

to the relation of suspended-sediment load to 

instantaneous streamflow for the study period at 

Cartoogechaye Creek (fig. 12). During 1977–79, more 

Table 6. Results of regression analyses relating the natural log of 

instantaneous suspended-sediment load to the natural log of instantaneous 

streamflow at three Little Tennessee River basin study sites in North Carolina

[R 2, coefficient of determination; P value, probability that the slope is equal to zero]

Site Intercept Slope 

coefficient R 2 P value

Mean 

of the 

antilog 

of the 

residuals

Cartoogechaye 

Creek

-1.44 1.98 0.72 0.00 1.57

Cullasaja River -2.23 2.09 .62 .00 1.44

Little Tennessee 

River at Riverside

-2.38 2.62 .80 .00 1.24

Table 7. Estimated suspended-sediment loads and yields at the three study sites and at sites sampled in 1970 – 79 in the Little 

Tennessee River basin, North Carolina 

[m3/ s, cubic meter per second; t, metric ton; t/km2, metric ton per square kilometer; —, no data]

Suspended sediment, 

2000 – 01

Suspended sediment, 

1970 – 79a

a

 From Simmons (1993).

Site

Annual-mean 

streamflow, 

in m3

/s

Load, in t, 

10 – 01 – 00 to 

12 – 31 – 01

Annual load, 

in t

Annual 

yield, 

in t/km2

Annual-mean 

streamflow, 

in m3

/s

Annual load, 

in t

Annual 

yield, 

in t/km2

Little Tennessee River at 

Riverside

b

 4.58

b

 Streamflow at the Prentiss, North Carolina, streamgage.

7,200 5,700 18 — — —

Cartoogechaye Creek near 

Franklin

2.09 1,300 1,000 7 4.39 10,000 81

Cullasaja River near 

Franklin

c

 3.4 1,500 1,200 5 — — —

Porter’s Bend dam at Lake 

Emory

c

 11 — 4,200 5 — — —

Little Tennessee River at 

Needmore

15.3 — — — 33.7 100,000 110

c

 Estimated.
Suspended Sediment 19

Figure 12. Relation of daily suspended-sediment load and instantaneous streamflow 

at Cartoogechaye Creek near Franklin, North Carolina, for 1977 – 79 and 2001.

samples were collected at high streamflow than during 

the study period when nearly 75 percent of the samples 

were collected at streamflows less than 2 m3/s because 

of drought conditions (fig. 12). Figure 12 indicates a 

decrease in the slope and intercept of the line 

determined by regressing streamflow on instantaneous 

load in 2001 compared with 1977–79. However, more 

samples are needed at streamflows greater than 10 m3

/s 

to adequately define the suspended-sediment load and 

streamflow relation for the 2001 water year.

Particle Size

Selected suspended-sediment samples were 

analyzed for particle size (table 8). Based on the small 

number of samples collected during this study, particle 

sizes were predominately finer than sand (finer than 

0.062 mm) at all of the sites (fig. 13). This, too, 

probably is an effect of low streamflows during the 

study. There was little variation in the median 

percentage of particles finer than 0.062 mm among the 

sites; however, as would be expected, the median 
20 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

Table 8. Streamflow and suspended-sediment concentration and particle-size distributions in samples from the four Little Tennessee River

basin study sites in North Carolina

[m3/ s, cubic meter per second; mg/L, milligram per liter; mm, millimeter; —, no data]

Percentage of suspended-sediment particles finer 

than the indicated size

Site Date Time

Instantaneous 

discharge, 

in m3

/s

Suspendedsediment 

concentration, 

in mg/L

0.062 

mm

0.125 

mm

0.250 

mm

0.500 

mm

1.00 

mm

aLittle Tennessee River at 

Riverside

a

 Streamflows are estimated for the Little Tennessee River at Riverside and Cullasaja River near Frankllin.

04–24–01 1000 4.7 11 70 — — — —

05–08–01 1000 3.9 8 81 — — — —

05–22–01 0900 3.6 24 85 — — — —

07–31–01 1240 11.1 441 86 92 97 100 100

09–26–01 1055 7.6 19 85 88 100 100 100

01–20–02 1130 13.4 87 64 68 100 100 100

01–23–02 1325 35.7 369 64 72 82 100 100

Cartoogechaye Creek near 

Franklin

04–24–01 1100 2.2 8 75 — — — —

05–08–01 1100 1.6 6 64 — — — —

05–22–01 1000 1.4 8 81 — — — —

07–31–01 1120 1.3 b 3

b

 Concentration was too low for full particle-size analysis.

95 — — — —

09–26–01 1151 1.6 b 2 100 — — — —

01–20–02 0952 8.6 79 70 70 89 100 100

01–23–02 1110 21.7 324 80 87 97 100 100

aCullasaja River near 

Franklin

04–24–01 1200 3.8 6 71 — — — —

05–08–01 1000 3.1 5 70 — — — —

05–22–01 1100 2.6 9 60 — — — —

07–31–01 1350 8.5 5 90 — — — —

09–26–01 1351 4.9 b 3 100 — — — —

01–20–02 1040 — b 15 100 — — — —

01–23–02 1215 22.4 114 79 85 100 100 100

Lake Emory at Porter’s 

Bend dam near Franklin

04–24–01 1300 — 8 93 — — — —

05–08–01 1300 — 9 93 — — — —

05–22–01 1200 — 35 77 — — — —

07–31–01 1020 — b 10 100 — — — —

09–26–01 1325 — b 9 100 — — — —
Bed Material 21

Figure 13. Distribution of percentages of suspended-sediment particles finer than 0.062 millimeter at the four 

Little Tennessee River basin study sites in North Carolina.

percentage of fine suspended-sediment particles 

(<0.062 mm) was greatest at Porter’s Bend dam.

BED MATERIAL

Sediment that is deposited on the streambed is 

bed material. Small particles can be resuspended during 

periods of elevated streamflow to produce suspendedsediment load (discussed previously). Larger particles 

that are too heavy to be suspended in the water column 

during elevated streamflows may move along the 

streambed as bed load.

Bed Load

Bed load is sediment that moves by sliding, 

rolling, or bouncing along on or near the streambed 

(Edwards and Glysson, 1999). Bed load is difficult to 

accurately measure because (1) any sampling device 

placed on the bed may disturb bed-load flow and rate of 

movement and (2) bed load is highly temporally and 

spatially variable. The material collected with the bedload sampler generally consists of material that is not 

collected by suspended-sediment sampling equipment.

Drought conditions during the study period 

limited opportunities for collecting bed-load samples 

because most bed load is carried during highstreamflow events. Three bed-load samples were 

collected at each stream site to estimate the amount of 

material that was being transported near the streambed 

and that was unaccounted for by the suspendedsediment sampler (tables 9, 10). Bed load was added to 

the suspended-sediment load calculated for a particular 

day to determine a total load. 
22 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02 Table 9. Bed load and suspended-sediment load during three runoff events at three sites in the Little Tennessee River basin in North Caro

[Samples were collected and composited at two cross sections from five or six equally spaced locations in the cross section; —, no data; <, less than] Daily-mean suspended- sediment load Daily-mean be

Date Time Discharge, in cubic meters per second Stream width, in meters Width of each section, in meters Sampling time at each section, in seconds Metric tons Metric tons per square kilometer Metric tons M

p

k

Little Tennessee River at Riverside (0349998425) 10–24–01 1305 4.3 6.7 1.34 1200 1.5 0.005 0.5 01–24–02 1421 19.4 5.8 3.81 180 79 .25 47 09–26–02 1538 29.4 19.2 1.16 300

—

— 42 

Cartoogechaye Creek near Franklin (03500240)10–24–01 1530 1.05 3.3 0.64 1200 0.13 0.001 0.004 01–24–02 1015 10.6 4.4 2.89 180 5.5 .037 3.3 09–26–02 1106 15.5 15.8 .88 300

—

— 5.1 

Cullasaja River near Franklin (0350116510)10–25–01 1500 3.3 4.8 0.98 1200 0.72 0.003 0.07 01–24–02 1224 12.4 5.8 1.16 180 3.2 .014 2.5 09–26–02 1312 18.4 20.7 3.44 300

—

— 5.3 
Summary 23

Not surprisingly, total load was significantly less 

during low flow than during high flow. Bed load was 

negligible at all three sites during low-flow conditions. 

Greatest daily bed load, in metric tons, and bed-load 

yield, in metric tons per square kilometer, was in the 

Little Tennessee River at Riverside during runoff 

events. Bed loads in Cartoogechaye Creek and the 

Cullasaja River were not substantially different from 

each other and were less than one-fifth the bed load and 

yield in the Little Tennessee River on the same day. Bed 

load accounted for 25 to 44 percent of the total 

sediment load in January 2002 when both bed and 

suspended-sediment loads were measured (table 9).

Particle Size

The bed-sediment particle-size distributions 

were similar at the two tributary sites for the dates 

sampled (table 10). The Little Tennessee River at 

Riverside transports slightly greater particle sizes than 

the tributaries. For the high-flow samples in January 

2002 and September 2002, more than 60 percent of the 

particles were finer than 0.5 mm in the tributaries, 

whereas less than 38 percent of the particles were finer 

than 0.5 mm in the Little Tennessee River at Riverside.

SUMMARY

A study of sediment transport in the upper Little 

Tennessee River basin was begun in June 2000 in 

cooperation with Macon County. The purpose of the 

study was to characterize bed and suspended-sediment 

loads into Lake Emory from the main stem and major 

tributaries—Cartoogechaye Creek and the Cullasaja 

River. The study was designed to be completed in 

1 year; however, because of extreme drought 

conditions in western North Carolina, some sampling 

continued into September 2002 in order to collect 

samples during high-flow conditions.

Weekly samples for suspended-sediment 

concentration were collected at the Little Tennessee 

River near Riverside, Cartoogechaye Creek near 

Franklin, the Cullasaja River near Franklin, and Lake 

Emory at the Porter’s Bend dam between November 

2000 and November 2001. In addition, some samples 

were collected during targeted high-flow events and 

analyzed for particle-size distribution of suspended 

sediment. Three bed-load samples were collected at 

each stream site and analyzed to determine mass and 

particle-size distribution. 

Annual suspended-sediment load was calculated 

based, in part, on continuous record of discharge for 

Cartoogechaye Creek near Franklin. Streamflow data 

Table 10. Particle-size distribution in bed-load samples from three sites in the Little Tennessee River basin in North Carolina

[m3/s, cubic meter per second; mm, millimeter]

Percentage of bed-load particles finer than size indicated

Date Discharge, 

in m3

/s 0.062 mm 0.125 mm 0.250 mm 0.500 mm 1.00 mm 2.00 mm 4.00 mm 8.00 mm 16.0 mm

Little Tennessee River at Riverside (0349998425)

10–24–01 4.3 0.2 0.4 8.5 59 90 97 99 100 100

01–24–02 19.4 0 0 4 29 74 96 99 100 100

09–26–02 29.4 .3 .7 4.6 38 91 100 100 100 100

Cartoogechaye Creek near Franklin (03500240)

10–24–01 1.05 2.2 2.2 16 58 71 76 78 84 100

01–24–02 10.6 0 1 12 70 92 97 99 100 100

09–26–02 15.5 .5 1.5 17 80 93 95 96 97 100

Cullasaja River near Franklin (0350116510)

10–24–01 3.3 .2 .8 13 66 79 85 90 93 100

01–24–02 12.4 0 0 10 73 94 98 99 100 100

09–26–02 18.4 .6 1.7 17 60 86 97 99 100 100
24 Suspended Sediment and Bed Load in Three Tributaries to Lake Emory in the Upper Little Tennessee River Basin, North Carolina, 2000 – 02

for the Little Tennessee River at Prentiss were used to 

estimate instantaneous streamflow record and 

suspended-sediment load at the Little Tennessee River 

at Riverside and Cullasaja River near Franklin. 

Streamflow at the Little Tennessee River at Needmore 

was used to estimate an annual-mean discharge for 

2001 for releases from Lake Emory. Equations relating 

estimated streamflow to suspended-sediment 

concentration were developed and used to compute 

estimates of annual suspended-sediment loads. 

Bed-load samples were collected in October 

2001 during low-flow conditions and in January and 

September 2002 during stormwater-runoff conditions. 

Bed-load samples were analyzed for weight and 

particle-size distribution. Selected suspended-sediment 

samples were analyzed for particle-size distribution.

For the study period, the greatest annual load and 

yield of suspended sediment (5,700 t and 18 t/km2

, 

respectively) was at the Little Tennessee River near 

Riverside. Much smaller annual yields were calculated 

for Lake Emory, the Cullasaja River, and 

Cartoogechaye Creek—5, 5, and 7 t/km2

, respectively.

In an earlier study in the 1970’s, the mean-annual 

suspended-sediment yield at Cartoogechaye Creek was 

81 t/km2 and 110 t/km2 at the Little Tennessee River at 

Needmore, which indicates a decline in sediment loads. 

The mean-annual suspended-sediment yield for 

relatively pristine, forested sites in the North Carolina 

Blue Ridge Province was 20 t/km2 for the Nantahala 

River near Rainbow Springs and 15 t/km2

 for 

Cataloochee Creek near Cataloochee. Drought 

conditions during the more recent study period 

probably were a factor in the small loads at these sites 

in 2001 compared to those in the 1970's and to forested 

reference sites. The annual-mean streamflow for the 

2001 water year was about 50 percent of the long-term 

annual-mean streamflow (1944–2001), and high-flow 

events carry most of the annual sediment load.

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