Prepared in cooperation with the National Park Service

Alluvial Bars of the Obed Wild and 

Scenic River, Tennessee

By W.J. Wolfe, K.C. Fitch,1 and D.E. Ladd

The river gorges of the Cumberland Plateau are notable for 

their biological diversity. The upland surface of the Plateau, sandstone cliffs, forested hillslopes, and whitewater river channels 

provide diverse habitats that support a wide variety of plants and 

animals, including many listed as rare, threatened, or endangered 

(RTE) by State or Federal government agencies (Schmalzer and 

others, 1985; Rouse, 1986; Schmalzer, 1989; Bailey and Coe, 2001). 

Protecting these diverse habitats is an important justification for 

the establishment of the Obed Wild and Scenic River (Obed WSR; 

fig. 1) and other National and State parks in Tennessee and nearby 

States. Seasonally flooded alluvial bars—discrete deposits of river 

sediment—are among the richest habitats for RTE plants in the 

Obed River and other Plateau gorges.

It is hereby declared to be the policy of the United States that certain 

selected rivers of the Nation which, with their immediate environments, 

possess outstandingly remarkable scenic, recreational, geologic, fish and 

wildlife, historic, cultural or other similar values, shall be preserved in 

free-flowing condition, and that they and their immediate environments 

shall be protected for the benefit and enjoyment of present and future 

generations. The Congress declares that the established national policy 

of dams and other construction at appropriate sections of the rivers of the 

United States needs to be complemented by a policy that would preserve 

other selected rivers or sections thereof in their free-flowing condition 

to protect the water quality of such rivers and to fulfill other vital national 

conservation purposes.

—Wild & Scenic Rivers Act, October 2, 1968

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 2007–2972

August 2007

1

 Tennessee Department of Environment and Conservation, Division of 

Natural Areas

Alluvial bars make up only a small part of the land surface 

in the Plateau gorges, but they support a disproportionately large 

number of RTE plants. For example, Schmalzer and others (1985) 

reported 9 of 16 (56 percent) RTE plant species growing in the Obed 

WSR on alluvial bars. Bailey and Coe (2001) reported that six of 

eight RTE plant species (75 percent) found along the Clear Fork and 

New River branches of the Big South Fork of the Cumberland River 

in Tennessee grow exclusively on alluvial bars. Despite the importance of alluvial bars as plant habitat, few scientific studies have 

focused on their geographic and physical characteristics or the role 

of hydrology in forming and maintaining these features in the Obed 

WSR and other Cumberland Plateau gorges. 

Introduction

In 2004, the U.S. Geological Survey (USGS) and the National 

Park Service (NPS) initiated a reconnaissance study of alluvial bars 

along the Obed WSR, in Cumberland and Morgan Counties, Tennessee (fig. 1). The study was partly driven by concern that trapping of 

sand by upstream impoundments might threaten RTE plant habitat 

by reducing the supply of sediment to the alluvial bars. The objectives of the study were to: (1) develop a preliminary understanding of 

the distribution, morphology, composition, stability, and vegetation 

structure of alluvial bars along the Obed WSR, and (2) determine 

whether evidence of human alteration of sediment dynamics in the 

Obed WSR warrants further, more detailed examination. 

This report presents the results of the reconnaissance study 

of alluvial bars along the Obed River, Clear Creek, and Daddys 

Creek in the Obed WSR (fig. 1). The report is based on: (1) fieldreconnaissance visits by boat to 56 alluvial bars along selected 

reaches of the Obed River and Clear Creek; (2) analysis of aerial 

photographs, topographic and geologic maps, and other geographic 

data to assess the distribution of alluvial bars in the Obed WSR; 

(3) surveys of topography, surface particle size, vegetation structure, 

and ground cover on three selected alluvial bars; and (4) analysis of 

hydrologic records.

Aerial view of Clear Creek. (Photograph courtesy of the National 

Park Service.)

The Obed Wild and Scenic River offers visitors a variety of outdoor 

recreational activities.
Figure 1. The Obed Wild and Scenic River and locations of alluvial bars along the Obed River and Clear Creek that were identified from aerial photographs or visited by boat. [Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).]

Fairfield Glade

FENTRESS

MORGAN

CUMBERLAND

Nemo Bridge

Lilly Bridge

Jett Bridge

Barnett Bridge

POTTER CHAPEL ROAD

62

298

298

0 0.5 1 2 MILES

0 0.5 1 2 KILOMETERS

84°55'0"W 84°50'0"W 84°45'0"W 84°40'0"W

36°5'0"N

36°10'0"N

Park boundary

County boundary

Highway

Road

ALLUVIAL BARS

Surveyed

Visited

Identified from aerial

 photograph

Base from Tennessee Department of Transportation digital data,

2000, 1:24,000; U.S. Geological Survey digital data, 1:1,000,000;

National Hydrography Dataset, 1:24,000; digital orthophoto

quarter-quads, 1-meter resolution; final map, Lambert Conformal

Conic projection, Standard parallels 35°15’ N and 36°25’ N,

central meridian 84°48’ W

Obed Junction

Fairfield Glade

Clear

Creek

Obed

River

Daddys

Creek

Obed

River

River

Emory

NEMO ROAD

TENNESSEE

CUMBERLAND

PLATEAU

Study

area

Crossville

Lake Tansi

Crab Orchard
What is an alluvial bar?

Alluvial bars are discrete (not continuous along the length of 

the channel) deposits of stream sediment (alluvium). Alluvial bars 

are commonly classified by composition, which can vary from clay 

to large boulders. Some alluvial bars appear, disappear, or shift position with every flood. Others were formed during extreme floods 

thousands of years ago and have changed little since. Alluvial bars 

can be rarely or frequently inundated or permanently underwater. 

They can be devoid of vegetation or heavily vegetated.

The alluvial bars described in this report are seasonally flooded, 

vegetated boulder bars—composed largely of rock particles at least 

10.08 inches, or 256 millimeters, in diameter (boulders). Boulders make up the structural framework of these alluvial bars and 

cover much of their surface area (fig. 2). Smaller cobbles (2.52–

10.08 inches or 64–256 millimeters in diameter) are common on 

most of these bars. Typically, the spaces between the boulders and 

cobbles are filled with sandy alluvium. Surface deposits of sand and 

silt are common. 

Information on the geometry of alluvial bars in the Obed WSR 

is limited. The three alluvial bars that were surveyed during this 

study ranged from 190 to 330 feet (58 to 100 meters) in length and 

from 105 to 150 feet (32 to 46 meters) in maximum width. The tops 

of the surveyed alluvial bars were 3 to 5 feet higher than the summer 

base-flow water surface.

How do alluvial bars form?

The boulders that dominate the composition of alluvial bars in 

the Obed WSR originate in the sandstone cliffs of the gorge walls. 

Sandstone blocks, periodically dislodged from the cliffs, may fall 

or roll to the bottom of the gorge (mass movement) (Remo, 1999), 

or they may be transported by debris flows down steep tributaries 

to the main channel (Moore, 1999). These processes supply enough 

boulders to the Obed River and other streams within the Obed WSR 

to provide the dominant bed material (fig. 3).

Boulder bars indicate hydraulic forces in the Obed River and 

its major tributaries sufficient to transport and deposit boulders. 

Determining what hydrologic conditions produce such forces and 

how frequently these conditions occur is problematic. The shapes and 

arrangement of boulders and other particles in the channel complicate the movement of coarse sediment. Rounded boulders need less 

energy to move than flat ones; isolated boulders are easier to move 

than those wedged together; boulders resting on a smooth channel bed move more readily than those on a rough bed. The relation 

between streamflow and boulder movement is further complicated by 

local variations in channel slope, water velocity, bed roughness, and 

similar factors.

In general, these complicating factors raise the water depth 

and velocity needed to move a given particle above theoretical or 

empirical thresholds based on simplifying assumptions about channel 

geometry, interactions between boulders, energy gradients, and turbulence (Williams, 1983; Komar and Li, 1986; Wohl, 1992). Despite 

their limitations, such thresholds provide a useful starting point for 

considering the hydrologic conditions that produced the alluvial 

bars of the Obed WSR. Williams (1983) derived a set of empirical 

thresholds of water velocity, channel-bed shear stress, and stream 

power needed to initiate movement of boulders and cobbles, based 

on a review of published studies. Williams’ lower thresholds are not 

explicitly linked to boulder shape, orientation, or bed characteristics, 

but probably apply to the most easily moved boulders.

Applying Williams’ (1983) lower boulder-movement thresholds 

to streamflow records suggests that minimum conditions to move 

3­‐foot boulders along the channel beds are common in the Obed 

WSR. For the Obed River near Lancing, discharge was related to 

channel-bed shear stress using two assumed channel slopes: 0.0045, 

based on the Lancing topographic quadrangle (U.S. Geological 

Survey, 1967), and 0.003, based on an indirect measurement of the 

Forest

Central clearing

Imbricated boulders

Figure 2. Photograph of the interior of a typical alluvial bar in the Obed Wild 

and Scenic River showing the central clearing, imbricated (leaning against 

each other with diagonal surfaces upstream) boulders, and forest vegetation 

near the boundary between the bar and the non-alluvial streambank.

Figure 3. Boulders are the dominant bed material of streams in the 

Obed Wild and Scenic River.
Alluvial bar

Non-alluvial

boulders

Rapid

Pool

Figure 4. Non-alluvial boulders are too large to be moved by observed river 

flows. These large boulders strongly influence river morphology, including 

the location of the alluvial bars, rapids, and pools.

May 27, 1973, flood (Charles Gamble, retired, U.S. Geological 

Survey, written commun., 1973). Depending on which assumed 

slope is used, the estimated minimum flow needed to move a 

3­‐foot boulder at the bottom of the channel is between 14,000 and 

32,000 cubic feet per second (ft3/s), with a recurrence interval of 

1 or 2 years near Lancing (fig. 5). 

Given frequent transport of large boulders in the channel, 

the most plausible mechanism for the formation of boulder bars 

is through the accretion of boulders in relatively stable locations. 

Alluvial bars form in places where sediment-laden flow loses 

power. In boulder-bed rivers, such locations commonly include 

major confluences, eddies or deflections of flow caused by large 

non-alluvial boulders (fig. 4) or other obstructions, and bends in the 

channel. Alluvial bars form as boulders accumulate in these lowenergy locations. Each new depositional event raises the surface of 

the bar, increasing the energy needed to bring subsequent boulders 

onto the new higher bar surface or to transport those already in 

place. Because the bars are located in relatively low-energy locations 

within powerful, boulder-rich channels, flows capable of transporting boulders across bar surfaces are likely to deposit more material 

than they remove.

Boulders transported by high-energy flow to locations of 

lower energy arrive as individual particles, but they form an ordered 

structure as they settle. Boulders at the surface of alluvial bars in the 

Obed WSR typically are imbricated—lain slantwise on each other, 

like shingles, with the downstream end higher than the upstream end 

(fig. 2). The imbricated arrangement of boulders on the alluvial bars 

is field evidence for deposition by flowing water and contributes to 

the stability of the bar surfaces through the mutual armoring and 

slanted upstream surfaces of the imbricated boulders.

How stable are the alluvial bars 

in the Obed WSR?

Evidence from published topographic maps and aerial 

photographs suggests that the locations and footprints of seasonally 

flooded alluvial bars in the Obed WSR are stable under current 

climatic conditions. The flood of May 27, 1973, with a peak flow 

for the Obed River near Lancing of about 105,000 ft3/s (fig. 5) and 

a recurrence interval of about 500 years, provides an opportunity to 

examine the effects of severe flooding on alluvial bars and channel 

geometry in general. Comparison of a pre-flood topographic map 

(U.S. Geological Survey, 1967) of the river channel near Nemo 

Bridge with a 1985 aerial photograph provided from the Tennessee 

Valley Authority (TVA) (fig. 6) shows little apparent change in the 

location and shape of major channel features, including numerous alluvial bars. Bars near the mouths of Clear Creek and Daddys 

Creek show similar stability. 

Stable locations and footprints do not necessarily mean that the 

bar surfaces are stable. On the contrary, the alluvial bars of the Obed 

WSR are “low energy” relative only to large rapids, cascades, hydraulic holes, and other sites of violently powerful flood flow. The surfaces of alluvial bars are high-energy settings when compared to most 

permanently vegetated habitats. Based on the deformation of a living 

maple tree on one alluvial bar, at least one large (greater than 3 feet) 

boulder was observed that had shifted position. Movement of smaller 

boulders across the surface of many bars may be relatively commonplace. Several of the visited bars had accumulations of large woody 

debris, including tree trunks with diameters of 2 feet or greater, that 

had been swept across the bar surface before coming to rest. 

Field observations and stream-gage records suggest that alluvial bars in the Obed WSR are flooded at intervals of years rather 

than decades. Flood debris, in the form of dead plant material, was 

observed in trees and shrubs several feet above the surface of several 

bars visited in spring and summer of 2004 (fig. 7). The largest 

floods that could have deposited the debris occurred in February and 

March 2004. The flood of February 6, 2004, had peak discharges 

of 41,700 and 16,900 ft3/s for the Obed River near Lancing and for 

Clear Creek at Lilly Bridge, respectively. Both discharges are near 

the 5-year flood for their respective stations. The March 6, 2004, 

flood approached the 10-year flood at Daddys Creek near Hebbertsburg, with a peak flow of 11,000 ft3

/s.

Spatial distribution of alluvial bars

Two sets of aerial photographs were used to examine the 

frequency and distribution of alluvial bars along the Obed River 

and Clear Creek. The primary set, covering the entire Obed WSR, 

was provided by the NPS Appalachian Highlands Inventory and 

Monitoring Network, Asheville, North Carolina. These photos are 

color-infrared (IR), taken in August 2001 with a nominal scale of 

1:12,000, scanned at 600 dots per inch (DPI), and geo-rectified. For 

Clear Creek downstream from Barnett Bridge and the Obed River 

downstream from Obed Junction (fig. 1), these color-IR photos were 

supplemented by aerial photographs on loan from TVA, taken in 

March 1985 at a nominal scale of 1:12,000 and scanned at 600 DPI. 

The third set of photos used in this analysis is the USGS orthophotographic quadrangle coverage, based on photos taken in 1997 at a 

nominal scale of 1:12,000. 

Figure 5. Streamflow record of the Obed River near Lancing from May 1, 1957, through December 31, 2006. [Annual peaks for periods with missing record estimated by simple linear regression from streamflow records of the Emory River 

at Oakdale. Assumed slope of 0.0045 based on the Lancing topographic quadrangle, scale 1:24,000 (U.S. Geological Survey, 1967). Assumed slope of 0.003 based on high-water marks used for indirect streamflow measurement following the 

May 27, 1973, flood.]

1967

1985

Figure 6. Before and after the 500-year flood. Footprints of alluvial bars 

along the Emory River near Nemo Bridge show little apparent change 

following the 105,000 cubic-feet-per-second flood of May 27, 1973. The 

USGS Lancing topographic quadrangle (top) was revised and published 

in 1967 and based on 1952 aerial photographs. The aerial photograph on 

the bottom was taken by the Tennessee Valley Authority in March 1985.

Figure 7. Flood debris, in the form of plant material hanging in the 

branches of trees and shrubs, 3 to 8 feet above the surface of an alluvial 

bar along Clear Creek, downstream from Jett Bridge.

Flood debris

0

1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005

20

40

60

80

100

Streamflow in thousands of cubic feet per second

Calculated threshholds to move 3-foot boulders

Daily average streamflow

Annual peak streamflow

Estimated annual peak streamflow

MISSING RECORD MISSING RECORD

Assuming slope of 0.0045

Assuming slope of 0.003
The color-IR photos and orthophotographic quadrangles were 

imported into a geographic information system (GIS) and examined 

using the GIS mapping program. The approximate center of each 

alluvial bar that could be identified was marked and saved as a point 

feature. Many of the bars could be distinguished from the valley side 

slopes by their shape, location, color, and texture. In some locations, 

shadows or photographic distortions made interpretation more difficult. Where available, the supplementary photos from TVA were 

used to resolve ambiguities in the interpretation. 

This analysis includes only alluvial bars that are clearly identifiable in at least one aerial photograph. Nearly half (26 of 56) of 

the alluvial bars visited during field reconnaissance were too small, 

too heavily vegetated, or too obscured by shadow or distortion to be 

included. The three surveyed bars, with approximate areas of 15,000 

to 30,000 square feet (ft2), were all clearly discernible on the photos. 

The analysis thus understates the number of alluvial bars in the 

Obed WSR and mainly reflects large (greater than 10,000 ft2 in area) 

bars with clearings. 

Aerial photographic analysis identified 201 alluvial bars along 

the 43 miles of Clear Creek and Obed River channel within the 

Obed WSR. The overall average density of the photo-mapped bars 

is 5 bars per mile of channel. Along the Obed River and the Emory 

River downstream from its confluence with the Obed, bar density 

appears to increase downstream (fig. 1). The average density of 

photo-mapped bars is 2 bars per channel mile from the upstream 

park boundary to Obed Junction and 7 bars per channel mile 

between Obed Junction and the downstream park boundary.

What is the ecological significance of 

alluvial bars in the Obed WSR?

Narrowly confined valleys and high energy regimes limit floodplain development in the Obed WSR. In the absence of floodplains, 

alluvial bars provide much of the available seasonally-flooded 

habitat. The distinctive geomorphic and hydrologic conditions of 

these bars have produced and maintained characteristic patterns of 

vegetation structure and composition. 

Sunny, glade-like clearings form the most striking feature of 

vegetation structure on the seasonally-flooded alluvial bars. The 

clearings dominate the highest, driest areas of the bar tops and 

commonly include exposures of imbricated boulders (fig. 2). Sandy 

or silty alluvium deposited on the surface or filling spaces between 

boulders provides the rooting medium for plants. Ample sunlight, 

permeable substrate, elevations 3 to 5 feet above summer base flow, 

and the absence of surface runoff other than floods give the bar-top 

clearings a distinctly xeric character, reflected in a characteristic 

flora of drought-resistant grasses, herbs, and low shrubs. Most of the 

RTE plants noted by Schmalzer and others (1985) on alluvial bars in 

the Obed WSR were found in the bar-top clearings. 

Plant assemblages of the bar-top clearings include several RTE 

species not normally found together (Schmalzer and others, 1985). 

Cumberland sandreed (Calamovilfa arcuata) grows in widely scattered locations from Tennessee to Oklahoma. Shortleaf sneezeweed 

(Helenium brevifolium) and pineywoods dropseed (Sporobolus junceus) are Coastal Plain natives. Cumberland rosemary (Conradina 

verticillata) (fig. 8) is endemic to the Obed gorge system and a few 

similar settings.

Thickets of flood-resistant shrubs typically dominate areas of 

the alluvial bars along the edge of water. These thickets typically 

include smooth alder (Alnus serrulata), common ninebark (Physocarpus opulifolius), Arrowwood species (Viburnum dentatum and

V. nudum var. cassinoides), and rhododendrons (Rhododendron 

spp.). One bar visited during this study had a large stand of Virginia 

spiraea (Spiraea virginiana), a federally listed RTE plant (fig. 8). 

The shrub thickets typically are rooted in alluvial silt deposits. Bars 

in contact with the valley wall typically have forest vegetation along 

their landward edge.

Figure 8. Two federally listed plants found on alluvial bars in the Obed Wild 

and Scenic River: Virginia spiraea (Spiraea virginiana) (left) and Cumberland 

rosemary (Conradina verticillata) (right, photo by Tara Littlefield, Kentucky 

State Nature Preserves Commission, used with permission).

What factors threaten plant communities 

on the alluvial bars?

Field observations do not indicate that trapping of sand by 

upstream impoundments is a major threat to plant habitats on alluvial bars in the Obed WSR. Surface deposits of sand and silt were 

found at most sites visited during this study. Because streamflow in 

the Obed WSR is frequently competent to transport sand and silt, the 

surface deposits indicate continuing supply of these materials to the 

channel. At sites where boulders dominated the surface, plants were 

observed rooted in sand or silt deposited in cracks between the boulders. The boulders at the surface act as an armor layer, protecting the 

interstitial sand and silt from erosive flows.

The distinctive plant communities of the bar-top clearings 

depend on seasonal patterns of flood and drought to resist competitive pressure from the surrounding trees and shrubs. Seasonal 

flooding suppresses upland forest vegetation on the bar tops through 

inundation and mechanical scouring. The shrub thickets at water’s 

edge are adapted to flooding but not to the drought conditions of the 

bar tops. 

A major shift in the balance between flood and drought could 

leave the bar-top clearings vulnerable to shading by encroaching 

trees or shrubs. Significant reduction of the frequency or severity 

of flooding would remove or reduce the periodic inundation and 

flood scouring that make the bar tops inhospitable to upland forest 

vegetation. Analysis of streamflow records indicates that no such 

reduction is presently occurring in the Obed WSR. Conversely, 

Background photograph: Clear Creek from the Lilly Bluff Overlook. 

Courtesy of the National Park Service.
Printed on recycled paper

increased summer base flow may have potential to reduce drought 

stress for flood-tolerant shrubs on the bar tops. Steamflow records 

for the Emory River at Oakdale show the running average of the 

5th percentile flow (exceeded 95 percent of the time) doubled from 

11.29 ft3/s in 1949 to 22.58 ft3/s in 2005 in response to wastewater 

releases from Crossville and nearby communities and increased 

regional precipitation (George S. Law, U.S. Geological Survey, written commun., 2007). It is unclear how much of an increase would 

be needed to affect vegetation structure on the bars or how sewage releases affect nutrient dynamics on the alluvial bars and other 

riverine habitats. 

Urban development has the potential to adversely affect water 

quality in the Obed WSR. The watershed of the Obed WSR includes 

the rapidly growing communities of Crossville, Fairfield Glade, Crab 

Orchard, and Lake Tansi. As these communities continue to grow, 

urban runoff will make up an increased proportion of streamflow in 

the Obed River and its tributaries. Urban runoff contains elevated levels of nutrients, pesticides, herbicides, metals, and organic solvents 

(Hampson and others, 2000). Any of these contaminants is a potential 

threat to the biota of the Obed WSR, including plants on the alluvial 

bars. The seriousness of this threat remains largely unexamined.

A more immediate threat to bar-top vegetation is the presence 

of non-native invasive plants (IPPs). IPPs were noted on at least 8 

of 56 alluvial bars visited in 2004. Five IPP species were identified: 

Sericea lespedeza (Lespedeza cuneata), autumn olive (Elaeagnus umbellate), silktree mimosa (Albizia julibrissin), crown vetch 

(Coronilla varia), and multiflora rose (Rosa multiflora). Multiflora 

rose was common on at least one of the bars and represents a serious 

threat to shade-intolerant native plants.

Acknowledgments

The authors acknowledge the generous assistance of several 

individuals. Elizabeth Fitch, Alex Rouse, and Brad Bryan (USGS) 

provided invaluable assistance in the field. Matt Hudson (NPS) 

provided logistical support and expert local knowledge of the rivers. Nancy Keohane (NPS) and Robert Emmott (NPS) made aerial 

photographs and other documents available. Jeff Hughes (NPS) and 

Tim Diehl (USGS) assisted in the field and reviewed preliminary 

drafts of this report. 

References

Bailey, C.J., Jr., and Coe, F.G., 2001, The vascular flora of the riparian zones of the Clear Fork River and the New River in the Big 

South Fork National River and Recreation Area (BSFNRRA): 

Castanea, v. 66, no. 3, p. 252–274.

Hampson, P.S., Treece, M.W., Jr., Johnson, G.C., Ahlstedt, S.A., and 

Connell, J.F., 2000, Water quality in the upper Tennessee River 

basin, Tennessee, North Carolina, Virginia, and Georgia, 1994–98: 

U.S. Geological Survey, Circular 1205, 32 p.

Komar, P.D., and Li, Zhenlin, 1986, Pivoting analyses of the selective entrainment of sediments by shape and size with application 

to gravel threshold: Sedimentology, v. 33, no. 3, p. 425–436.

Moore, D.A., 1999, The origins of rapids in the lower New River 

Gorge, West Virginia: Morgantown, West Virginia University, 

M.S. thesis, 60 p. 

Remo, J.W.F., 1999, Geologic controls on mass-movements in the 

New River Gorge, West Virginia: Morgantown, West Virginia 

University, M.S. thesis, 107 p.

Rouse, G.D., 1986, Rare plants of the New River Gorge National 

River, in Proceedings of the New River Symposium: Elkins, 

West Virginia, p. 123–129.

Schmalzer, P.A., 1989, Vegetation and flora of the Obed River and 

gorge system, Cumberland Plateau, Tennessee: Journal of the 

Tennessee Academy of Science, v. 64, no. 3, p. 161–168. 

Schmalzer, P.A., Patrick, T.S., and DeSelm, H.R., 1985, Vascular 

flora of the Obed Wild and Scenic River, Tennessee: Castanea, 

v. 50, no. 2, p. 71–88.

U.S. Geological Survey, 1967, Lancing topographic quadrangle, 

1:24,000: Washington, D.C., U.S. Geological Survey.

Williams, G.P., 1983, Paleohydrological methods and some examples from Swedish fluvial environments. I. Cobble and boulder 

deposits: Geografiska Annaler, Series A, Physical Geography, 

v. 65A, p. 227–243.

Wohl, E.E., 1992, Bedrock benches, and boulder bars—floods in 

the Burdekin Gorge of Australia: Geological Society of America 

Bulletin, v. 104, p. 770–778.

For additional information regarding this publication, contact: 

Director

USGS Tennessee Water Science Center

640 Grassmere Park, Suite 100

Nashville, TN 37211

phone: 615–837–4700

Please visit the USGS Tennessee Water Science Center website at:

	 http://tn.water.usgs.gov/

Any use of trade, product, or firm names is for descriptive purposes only and does 

not imply endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from 

the individual copyright owners to reproduce any copyrighted materials contained 

within this report.

U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

Conversion factors

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square foot (ft2) 0.09290 square meter (m2)

Flow rate

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

Mass

pound, avoirdupois (lb) 0.4536 kilogram (kg)