Prepared in cooperation with the U.S. Army Corps of Engineers, Portland District

Preliminary Assessment of Vertical Stability and Gravel 

Transport along the Umpqua River, Southwestern Oregon 

By Jim E. O’Connor, J. Rose Wallick, Steven Sobieszczyk, Charles Cannon, and Scott W. Anderson

Open-File Report 2009–1010

U.S. Department of the Interior

U.S. Geological Survey
Cover: Umpqua River at river mile 90.7, looking upstream, November 3, 2008 (Photograph by Jim O’Connor, 

U.S. Geological Survey)
Preliminary Assessment of Vertical Stability and Gravel 

Transport along the Umpqua River, Southwestern Oregon 

By Jim E. O’Connor, J. Rose Wallick, Steven Sobieszczyk, Charles Cannon, and Scott W. Anderson

Prepared in cooperation with the U.S. Army Corps of Engineers, Portland District

Open-File Report 2009–1010

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2009

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS. 

For an overview of USGS information products, including maps, imagery, and publications,

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Suggested citation:

O’Connor, J.E., Wallick, J.R., Sobieszczyk, Steven, Cannon, Charles, and Anderson, S.W., 2009, Preliminary 

assessment of vertical stability and gravel transport along the Umpqua River, Oregon: U.S. Geological Survey 

Open-File Report 2009–1010, 40 p. 

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 material contained within this report.
iii

Contents

Significant Findings....................................................................................................................................................1

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

Physical Setting of the Umpqua River Basin..............................................................................................................4

Approach and Key Findings.....................................................................................................................................10

Compile and Review Historical Documents and Photographs .............................................................................10

Compilation of Historical Maps and Survey Data ................................................................................................. 14

Assessment of Aerial Photographs ......................................................................................................................16

Review of Water- and Sediment-Related Studies in the Umpqua River Basin.....................................................19

Review of Gravel-Operator Surveys.....................................................................................................................20

Compile and Review Oregon Department of Transportation Umpqua River Bridge Inspection Reports..............23

Specific Gage Analysis ........................................................................................................................................23

Mapping of Gravel Bars and Channel Features ...................................................................................................26

Gravel Bar Particle Size Analyses........................................................................................................................33

Summary of Findings...............................................................................................................................................36

Outstanding Issues and Possible Approaches.........................................................................................................36

Bed-Material Budget ............................................................................................................................................36

Legacy and Ongoing Effects of Placer Mining, Forest Practices, Impoundments and Instream Gravel Mining ...37

Connections between Upstream Umpqua River and Tributaries and the Tidal Reach.........................................37

Balance between Sediment Supply and Transport Capacity................................................................................38

References Cited.....................................................................................................................................................39

Figures

Figure 1. Maps showing (A) location of designated valley reaches and (B) geomorphic subdivisions 

(Ramp, 1972) for the Umpqua River basin and Douglas County, southwestern Oregon. ................................. 3

Figure 2. Longitudinal profile, cumulative drainage area, valley reach boundaries, and locations of 

streamflow-gaging stations for the Umpqua River, southwestern Oregon........................................................4

Figure 3. Annual peak flows for selected USGS streamflow-gaging stations in the Umpqua River basin, 

southwestern Oregon. ..................................................................................................................................................9

Figure 4. Circa 1890s photograph of South Umpqua River upstream of Mount Nebo near Roseburg, 

Oregon. Courtesy Douglas County Museum (Photograph N5549a) ...................................................................12

Figure 5. Hydraulic mining in the Olalla District, Lookingglass Creek drainage, Oregon. Courtesy of 

Douglas County Museum (Photograph N5155), undated. ....................................................................................14

Figure 6. Summary of gravel bar volume changes, 2000–2008, at instream gravel mining sites along the 

South Umpqua River, southwestern Oregon..........................................................................................................21

Figure 7. Excavation volumes for 1949–2002, for the Umpqua River Navigation (and successor 

companies) mining site along lower Umpqua River below RM 27, southwestern Oregon............................23

Figure 8. Sequence of stage-discharge rating curve elevations for specific discharges for long-term 

mainstem streamflow gages in Umpqua River, Oregon, study area.................................................................. 25

Figure 9. Distribution and size of fluvial sediment accumulations in the Umpqua River, southwestern 

Oregon, study area as mapped from 2005 National Agriculture Imagery..........................................................26
iv

Figure 10. Mapped bar areas for selected reaches of the Umpqua River basin, southwestern Oregon, 

from aerial photographs dated 1939, 1967, and 2005 .............................................................................................27

Figure 11. Mapped channel and bar features for the Umpqua River at Tyee site, southwestern Oregon, 

1939–2005. ......................................................................................................................................................................30

Figure 12. Mapped channel and bar features for the Umpqua River at Cleveland Rapids site (RM 107.5–

110.5), southwestern Oregon, 1939–2005. ................................................................................................................31

Figure 13. Mapped channel and bar features at the South Umpqua River site (RM 128–132), 

southwestern Oregon, 1939–2005..............................................................................................................................31

Figure 14. Mapped channel and bar features at the North Umpqua River site (RM 9–12.5), southwestern 

Oregon, 1939–2005........................................................................................................................................................32

Figure 15. Mapped channel and bar features at the Lower Umpqua River site (RM 8–13), southwestern 

Oregon, 1939–2005........................................................................................................................................................33

Figure 16. Particle-size distribution for gravel bars In the North Umpqua River basin, southwestern 

Oregon, sampled during a November 2008 field reconnaissance.......................................................................35

Tables

Table 1. Summary of geomorphic and channel characteristics for valley reaches in the Umpqua River 

basin, southwestern Oregon .......................................................................................................................................1

Table 2. List of maps reviewed for this study of the Umpqua River basin, southwestern Oregon.............15

Table 3. List of aerial photographs reviewed for this study of the Umpqua River basin, southwestern 

Oregon...........................................................................................................................................................................16
v 

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

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

cubic yard (yd3) 0.7646 cubic meter (m3) 

foot (ft) 0.3048 meter (m)

meter (m) 3.281 foot (ft) 

mile (mi) 1.609 kilometer (km)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

ton per year (ton/yr) 0.9072 metric ton per year

ton, short (2,000 lb) 0.9072 megagram (Mg) 

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 29).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

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

This page is intentionally blank.
1 

Preliminary Assessment of Vertical Stability and Gravel 

Transport along the Umpqua River, Oregon

By Jim E. O’Connor, J.Rose Wallick, Steven Sobieszczyk, Charles Cannon, and Scott W. Anderson

Significant Findings

This preliminary study of (1) gravel transport in the Umpqua River basin, (2) possible historical changes 

to physical channel and floodplain conditions, and (3) potential future studies reveals that: 

• The alluvial reaches of the Umpqua River system can be divided into six valley reaches based on 

geomorphology, hydrology, and land-use history. The mainstem Umpqua River can be divided into 

the Tidal, Coast Range, and Garden Valley Reaches; the South Umpqua River can be divided into 

the Roseburg and Days Creek Reaches; and the alluvial portion of the North Umpqua River is a 

single reach consisting of the lowermost 29 river miles upstream of the South Umpqua confluence. 

These reaches and their contributing areas differ in their capacity to produce, store, and transport 

bed-material sediment.

• Historical accounts and information dating to the 1820s demonstrate that the Umpqua River, aside 

from the Tidal Reach, flowed on bedrock for much of its length. Sand and gravel accumulations 

were notably sparse. These two observations indicate that the channel is incising over geological 

timescales and that sediment transport is limited by supply. 

• The primary human activities that have likely had effects on bed material transport and the extent 

and volume of gravel bars are (1) intense placer mining (including hydraulic quarrying of alluvium) 

beginning in the 1850s, especially for tributaries of the South Umpqua River; (2) dam building on 

the North Umpqua River and in the Cow Creek drainage (tributary to the South Umpqua River); (3) 

road building and forest practices in upland areas; (4) inchannel dredging in the Tidal Reach; and (5) 

gravel mining from active gravel bars, primarily in the Tidal, Garden Valley, Roseburg, and Days 

Creek Reaches. These influences have likely had spatially and temporally varying effects on gravel 

transport rates and the size and volume of gravel bars. For some reaches, disentangling these various 

factors will be challenging.

• Several sources of historical maps, surveys, and aerial photographs could support quantitative 

analysis of plan-view changes and riparian conditions dating back to the General Land Office 

surveys of the 1850s. Some information is available, including channel navigation and flood studies, 

which could be used to evaluate changes in channel bathymetry.

• Previous sediment studies conducted for water years 1956–73 indicate that at their confluence, the 

South Umpqua River contributes more than twice the sediment as the North Umpqua River, with 

Cow Creek being the major contributor to the South Umpqua River. 

• Repeat gravel bar and channel surveys provided by gravel mining companies and other sources 

indicate that extracted volumes are not rapidly replenished in the Tidal Reach, with possible incision 

indicated by the latest 2002 surveys, and that bars in the Roseburg and Days Creek Reaches (on the 
2 

South Umpqua River) have been rebuilding since last mining in 2004, especially after high flows in 

2005–06. 

• Reviews of approximately 35 bridge inspection reports indicate that nearly all bridge piers are set in 

bedrock. Some footings show scour that is mostly attributable to bedrock erosion. 

• Specific gage analyses for gages on the mainstem Umpqua River (near Eldon), South Umpqua River 

near Brockway, and the North Umpqua River at Winchester show little or no incision over their 

periods of record. 

• Systematic mapping of observable gravel bars for all reaches from 2005 aerial photographs shows 

that the Tidal Reach has by far the greatest area of fluvial sediment surfaces, but many of these are 

mud and sand flats. Elsewhere, the Roseburg Reach (South Umpqua River) stands out as having the 

most abundant gravel bars, indicating much greater bed-material production rates for the South 

Umpqua River and in particular the importance of Cow Creek in contributing bed sediment. 

• Analyses of aerial photograph sequences for five short reaches for 1939, 1967, and 2005 show no 

clear trends, but extending this analysis for more reaches and more time periods would be necessary 

to determine if trends in gravel bar area, riparian conditions, and channel morphology exist. 

Introduction

This report addresses physical channel issues related to instream gravel mining on the Umpqua 

River and its two primary tributaries, the North and South Umpqua Rivers. This analysis constitutes a 

“Phase I” investigation, as designated by an interagency team cochaired by the U.S. Army Corps of 

Engineers, Portland District, and the Oregon Department of State Lands to address instream gravel 

mining issues across Oregon. Phase I analyses rely primarily on existing datasets and cursory analysis to 

determine the vertical stability of a channel to ascertain whether a particular river channel is aggrading, 

degrading, or at equilibrium. Additionally, a Phase I analysis identifies other critical issues or questions 

pertinent to physical channel conditions that may be related to instream gravel mining activities. 

This analysis can support agency permitting decisions as well as possibly indicating the need for 

additional studies. This specific analysis focuses on the mainstem Umpqua River from the Pacific 

Ocean at River Mile (RM) 0 to the confluence of the North and South Umpqua Rivers (at RM 111.8), as 

well as the lower 29 mi of the North Umpqua River and the lower 80 mi of the South Umpqua River 

(fig. 1). It is within these reaches where mining of gravel bars for aggregate has been most prevalent. 
3 

Figure 1. (A) location of designated valley reaches and (B) geomorphic subdivisions (Ramp, 1972) for the Umpqua 

River basin and Douglas County, southwestern Oregon.
4 

Physical Setting of the Umpqua River Basin

The Umpqua River drains 4,673 mi2 of western Oregon before draining into the Pacific Ocean at 

Winchester Bay near the town of Reedsport (fig. 1). The drainage basin is flanked to the north by the 

Siuslaw and Willamette River basins, to the east by the Deschutes and Klamath River drainages, and to 

the south by the Rogue and Coquille River basins. The basin has its headwaters in the Cascade Range is 

bounded on the south by the Klamath Mountains, and transects the Coast Range before entering the 

Pacific Ocean. The North and South Umpqua Rivers join in the generally lower terrain between the 

Cascade Range and the Coast Range, with the North Umpqua River draining parts of the High Cascades 

and Western Cascade physiographic provinces, and the South Umpqua River draining parts of the 

Western Cascades and Klamath Mountain provinces. The lower parts of both forks, as well as the 

mainstem Umpqua River, are wholly within the Coast Range physiographic province (fig. 1B, Ramp, 

1972). 

After exiting the Western Cascades physiographic province, the North and South Umpqua 

Rivers flow generally westward before joining 6 mi northwest of Roseburg. For another 12 mi, the 

mainstem Umpqua River meanders northwestward though two large valleys before bisecting the higher 

portion of the Coast Range within a narrow valley trending northwest and then west for 90 mi before 

exiting into the coastal plain for the last 10 mi before entering the Pacific Ocean. The main tributaries of 

the mainstem Umpqua River are the Smith River (371 mi2

), Elk Creek (292 mi2), and the Calapooya 

River (246 mi2). The Umpqua River begins at the confluence of North Umpqua and South Umpqua 

Rivers at RM 111.8, where the North Umpqua River drains 1,359 mi2

, with all major inflow entering 

upstream of the study area at Little River (206 mi2) and Steamboat Creek (164 mi2). At the confluence, 

the South Umpqua River has a drainage area of 1,801 mi2

, with the main tributaries in the study area 

being Lookingglass Creek (161 mi2), Myrtle Creek (119 mi2), Cow Creek (499 mi2), and Jackson Creek 

(189 mi2) (figs. 1 and 2). 

Figure 2. Longitudinal profile, cumulative drainage area, valley reach boundaries, and locations of 

streamflow-gaging stations for the Umpqua River, southwestern Oregon. Drainage area calculated 

from USGS 10-meter digital elevation data.
5 

The study area encompasses the downstream alluvial sections of the North and South Umpqua 

Rivers and the entire mainstem Umpqua River. For both forks, the alluvial sections begin where the

rivers exit the mountainous headwaters, widen, and flow on a mixed bed of bedrock and alluvium 

flanked by variable widths of floodplain and terraces. For the North Umpqua River, this transition to a 

dominantly alluvial character approximately corresponds with the confluence of the Little River at RM 

29.1 (river miles for the North Umpqua River are measured with respect to the confluence with the 

South Umpqua River.) Downstream of the Little River confluence, the North Umpqua River is generally 

200 to 300 ft wide and flows on a bed of sandstone and basalt, locally mantled by thin accumulations of 

sand and gravel. The average gradient from the Little River confluence to the confluence with the South 

Umpqua River is 0.0018 (table 1). In this reach, the North Umpqua River is flanked by a valley bottom 

typically less than 0.5 mi wide formed of recent floodplain deposits and small terrace remnants.
Table 1. Summary of geomorphic and channel characteristics for valley reaches in the Umpqua River basin, southwestern Oregon—continued

Valley Reach

Attribute Tidal Coast Range Garden Valley Roseburg Days Creek North Umpqua

Position RM 0–27.5 RM 27.5–100 RM 100–111.8 RM 111.8–158.9 RM 158.9–192.4 RM 0–29.0

Reach definition Tidally affected Confined valley, 

bedrock channel

Unconfined below 

North and South 

Umpqua River 

confluence

Cow Creek 

confluence to North 

Umpqua River 

confluence

Jackson Creek 

confluence to Cow 

Creek confluence

Little River 

confluence to South 

Umpqua River 

confluence

General valley setting Estuary, confined 

valley opening to 

bay within coastal 

plain

Confined valley 

with local valley

widenings

Unconfined Alternating confined 

and unconfined 

Alternating 

confined and 

unconfined

Alternating confined 

and unconfined

General channel character Low gradient, 

sand and gravel 

bed

Steep, bedrock 

rapids separated 

by flats

Alternating 

bedrock and gravel

Alternating bedrock 

and gravel

Mostly bedrock, pool 

and drop

Area at downstream end of 

segment (square miles) 4,672.7 4,051.1 3,438.0 1,801.6 757.4 1,359.8

Area at upstream end of 

segment in (square miles) 4,051.1 3,438.0 3,161.5 1,256.4 435.3 1,216.8

Average gradient 0.00012 0.00073 0.00098 0.00100 0.00249 0.00177

Number of bars 5 17 5 72 33 24

Gravel bars per river mile 0.07 0.09 0.15 0.55 0.35 0.28

Total area of gravel bars (acres) 22,782.6 91.9 18.7 261.6 123.2 38.9

Average gravel bar area (acres) 4,556.52 5.41 3.75 3.63 3.73 1.62

Gravel area per mile of river 

(acres/mile) 848.53 1.35 1.53 5.45 3.60 1.25

Major flow factors Tidally affected Minimal 

regulation

Minimal regulation Galesville 

Reservoir, closed 

October 7, 1985, 

regulates 74.3 

square miles of Cow 

Creek basin (5.9% 

of contributing area 

at upper end of 

segment)

None Pacific Power dams 

constructed 1952–

1955 regulate 

(slightly) 430 square 

miles (35% of the 

area at the upper end 

of segment)

6 
Table 1. Summary of geomorphic and channel characteristics for valley reaches in the Umpqua River basin, southwestern Oregon—continued

Valley Reach

Attribute Tidal Coast Range Garden Valley Roseburg Days Creek North Umpqua

Major sedimentation factors Change in 

gradient promotes 

deposition of 

bedload and 

suspended load, 

Smith River 

sediment inputs, 

(100,000–500,000 

cubic yards per 

year), sand and 

gravel removal.

Tributary 

sediment inputs, 

local landuse and 

forest practices

Local sand and 

gravel mining, 

forest practices, 

Calapooya River 

sediment input

Late 19th century 

placer mining (Cow 

Creek, Myrtle 

Creek, Canyon 

Creek, and South 

Umpqua River), 

forest practices, 

sand and gravel 

mining, tributary 

sediment inputs

Forest practices, 

sand and Gravel 

mining, tributary 

sediment inputs

Pacific Power dams 

trap upstream 

sediment, land-use

Channel disturbance factors Historic 

navigation 

dredging, sand 

and gravel 

mining, rock 

removal for 

navigation 

improvement near 

Scottsburg, road 

corridor

Late 19th 

century 

navigation 

improvements, 

temporary mill 

dam at Kellogg 

(removed 1871), 

road corridor

Late 19th century 

navigation 

improvements, 

sand and gravel 

mining

Local navigation 

improvements, 

transportation 

infrastructure, log 

driving, sand and 

gravel mining, 

placer mining, 19th 

century mill dams

Transportation 

infrastructure, sand

and gravel mining, 

log driving(?), 

placer mining

Navigation 

improvement, log 

driving, Winchester 

Dam at RM 7 

General channel trends Some evidence of 

local incision 

historically near 

gravel mining 

operations 

(CH2M-Hill, 

1971; Janine M. 

Castro, written 

commun., 2008)

Channel 

historically and 

presently on 

bedrock. Little or 

no evident 

change (photos, 

specific gage 

analysis for 

Elkton gage).

Channel 

historically and 

presently on 

bedrock. No 

obvious change 

evident from 

inspection of aerial 

and oblique 

photographs, 

analysis of bar 

area.

Channel historically 

and presently on 

bedrock. No obvious 

change evident from 

inspection of aerial 

and oblique 

photographs, 

analysis of bar area, 

and specific gage 

analysis.

Channel locally on 

bedrock. No 

evident trends, 

although limited 

data for this reach.

Channel historically 

and presently on 

bedrock. No evident 

change from specific 

gage analysis.

7
8 

For the South Umpqua River, the confluence of Jackson Creek at RM 192.5 (measured with 

respect to the Pacific Ocean) near Tiller approximately marks the transition from a confined mountain 

channel to a mixed alluvial and bedrock channel locally flanked by active gravel bars, floodplain 

surfaces, and terraces. For the 33.5 mi between the Jackson Creek and Cow Creek junctions, the South 

Umpqua River flows generally westward with an average gradient of 0.0025 (table 1) and a width 

typically less than 150 ft. In this reach, the valley alternates between confined canyon reaches and 

sections as wide as 1 mi. Wider sections contain channel-flanking gravel bars, floodplains, tributary 

fans, and terrace deposits. 

With the confluence of Cow Creek at RM 158.9, the drainage area of the South Umpqua River 

increases by about one-third and the channel widens to between 200 and 400 ft. For the 47.1 mi reach 

between the Cow Creek confluence to the junction with the North Umpqua River, the South Umpqua 

River flows generally northward on an alternating bed of bedrock and alluvium with a average gradient 

of 0.001 (table 1), winding through canyons alternating with valleys as wide as 2 mi, and is locally 

flanked by gravel bars, floodplains, and terraces. 

The general character of the South Umpqua River continues another 12 mi downstream of the 

confluence with the North Umpqua River, where the Umpqua River enters a confined section at RM 

100. From here to about RM 25, the river flows within deep and narrow meanders incised through the 

Coast Range, with narrow flanking floodplains and terraces almost everywhere less than 0.5 mi wide. 

The channel in this reach is typically 300 to 600 ft wide and consists of long pools separated by bedrock 

rapids; the average gradient between RM 100 and the head of tide at RM 27.5 is 0.0073 (table 1). From 

RM 25 to the mouth, the Umpqua River is tidally affected, progressively widens, and is flanked by low 

floodplains, tidal marshes and sand and gravel bars, especially downstream of the mouth of the Smith 

River at RM 11. 

Information on basin hydrology derives from U.S. Geological Survey (USGS) streamflowmeasurement records in the basin extending discontinuously back to 1905. Much of these data are 

available at http://waterdata.usgs.gov/or/nwis/nwis, with some synthesis provided by Jones and Stearns 

(1930). The mean annual flow of the Umpqua River near Elkton, at RM 56.9 is 7,365 ft3

/s, which 

closely corresponds to the combined mean flows for the North Umpqua River at Winchester (RM 1.8; 

3,698 ft3/s), and the South Umpqua River near Brockway (RM 132.8, 2,755 ft3/s). Despite a 

contributing area 25 percent smaller than the South Umpqua River, the North Umpqua River supplies 

more than 50 percent of the water at Elkton (compared to 37 percent provided by the South Umpqua 

River), chiefly owing to a greater area of high elevation terrain subject to orographically enhanced 

precipitation. This high terrain, associated with Quaternary volcanic rocks of the High Cascade 

physiographic province, also explains the much lower intraannual flow variability of the North Umpqua 

River, where the mean January flow is only 6.7 times that of August. By contrast, the mean January 

flow for the South Umpqua River is 57 times greater than the mean August flow. The young volcanic 

uplands of the North Umpqua River headwaters have poorly integrated surface drainage networks and 

host large-volume ground-water systems, attenuating surface runoff and feeding large spring complexes 

that maintain high dry season flows in comparison with more rapid runoff derived from the more 

dissected and older rocks of the Western Cascades and Klamath Mountain terrains underlying much of 

the South Umpqua River headwaters (Jones and Stearns, 1930). 

Peak flows in the Umpqua River basin typically derive from winter frontal systems, with the 

largest flows resulting from regional rain-on-snow events. The peak of record for both forks and the 

mainstem was in late December 1964, when 265,000 ft3

/s was reported for the mainstem near Elkton, 

and 150,000 and 125,000 ft3/s were reported for the North Umpqua and South Umpqua Rivers, 

respectively. The 1964 flood probably was the largest since the rain-on-snow flood of 1861. The 2-year-
9 

recurrence-interval flow is about 49,000 ft3/s for the North and South Umpqua Rivers, and 94,500 ft3/s 

for the mainstem Umpqua River (Harris and others, 1979). Since the early 1950s, flow has been slightly 

regulated by Pacific Power hydroelectric projects on the North Umpqua River; likewise, on the South 

Umpqua River, construction of Galesville Reservoir in 1985 on Cow Creek may slightly affect peak and 

low flows, although plots of peak flows (fig. 3) show no marked effect of the dams for either river.

Figure 3. Annual peak flows for selected USGS streamflow-gaging stations in the Umpqua 

River basin, southwestern Oregon. 

Sediment conditions owe to the combined effects of geology, physiography, hydrology, and land

use. Little specific work has been reported for much of the Umpqua River basin, with the exception of 
10

the sediment budget analysis for the North Umpqua River conducted as part of the Federal Energy 

Regulatory Commission (FERC) relicensing of Pacific Power’s North Umpqua Hydroelectric Project 

(Stillwater Sciences, 2000) and USGS sediment studies conducted in the 1960s and 1970s (Onions, 

1969; Curtiss, 1975). The primary factors that exacerbate hydrologic responses—high drainage 

densities, high relief, older and erodible rocks—likely also promote greater supplies of bed material 

(see, for example, O’Connor and others, 2003). Consistent with this is the finding of Curtiss (1975) that 

the South Umpqua River produces an annual sediment discharge more than twice that of the North 

Umpqua River, based on USGS suspended-load measurements at multiple sites between 1956 and 

1973,. Nevertheless, the common occurrence of inchannel bedrock for both forks and the mainstem 

upstream of the tidal reach indicates that bed material transport is limited by the amount supplied from 

upstream and tributaries. 

The overall physical setting, as well as the distribution of instream gravel-mining permits 

(Oregon Department of State Lands, written commun., 2008), lends itself to delineation of valley 

reaches to help organize sediment-related issues, analyses, and findings (fig. 1; table 1). These reaches 

are, from downstream to upstream (1) Tidal Reach, between RM 0 and approximately 28, distinguished 

by low gradients, expansive sediment deposits, and historic gravel sand and gravel removal for 

navigation and aggregate; (2) Coast Range Reach, between approximately RM 28 and 100, 

characterized by a confined valley with bedrock channel and few gravel deposits; (3) Garden Valley 

Reach of broad valleys, between where the Umpqua River enters the Coast Range at RM 100 and the 

North Umpqua River and South Umpqua River confluence at approximately RM 112, a reach of historic 

instream gravel mining; (4) Roseburg Reach of the South Umpqua River, between the confluence with 

the North Umpqua River (RM 112) and the Cow Creek confluence at RM 158.9, where there are 

abundant gravel bars and several recently active instream gravel mining operations; (5) Days Creek 

Reach of the South Umpqua River, between the Cow Creek confluence at approximately RM 159 and 

192, which constitutes the uppermost alluvial reach of the South Umpqua River; and (6) North Umpqua 

River, between RM 0 and the Little River confluence at RM 29, a reach locally flanked by alluvial 

deposits but with no recent instream gravel mining. 

Approach and Key Findings

For this study, we reviewed existing datasets, collected data, and analyzed information regarding 

channel processes and gravel transport for the Umpqua River. In addition, we conducted site visits in 

August and November 2008. These activities were focused on assessing physical river conditions and 

trends—in particular the locations, area, and extent of gravel bars and information pertaining to channel 

aggradation or incision. We also examined broader land-use and geomorphic factors pertinent to gravel 

transport, distribution, and links to physical habitat conditions. The scope was such that the data review 

and analyses were not necessarily exhaustive, but focused on gathering information to evaluate present 

trends and conditions, identify outstanding questions, and guide future studies. The following sections 

summarize each of the major activities and key findings. 

Compile and Review Historical Documents and Photographs

We reviewed several Umpqua River basin historical documents (largely summarized by 

Beckham [1986] and Winterbothom [1994, 2000]) for observations and accounts pertinent to channel 

conditions. The most useful of these are reports of early exploration and navigation surveys 

documenting channel characteristics at first European-American settlement. Accounts of historic landuse activities possibly affecting channels also were useful. Abundant archival photographs, at the 
11

Douglas County Historical Society and elsewhere, locally document channel conditions as far back as 

circa 1900. 

A primary conclusion from inspection of these historical sources is that gravel was scarce in 

many reaches of the Umpqua River. This is particularly evident for the Coast Range Reach of the 

mainstem Umpqua River. For example, David Douglas, a botanist (and county namesake) 

accompanying an expedition of the Hudson’s Bay Company, describes his evening activities at their 

camp near Elkton (Douglas, 1914, p. 223; RM 48.5; Coast Range Reach):

 “I employed myself chopping wood, kindling the fire, and forming the encampment; and after, in 

the twilight, bathed in the river: course north-west; bed sandstone; ninety yards broad; not deep, but 

full of holes and deep chinks worn out by the water.” 

Similarly John Work, employed by the Hudson’s Bay Company, describes following the 

mainstem Umpqua River between Elkton and Scottsburg (RM 27.5) in his journal entry for June 8, 1834 

(Scott, 1923): “No stones worth mentioning all the way: the river runs on a bed of soft slatey rock.” 

Two weeks later, on June 17, John Work was camping along the Umpqua River just downstream of the 

Calapooya River confluence (RM 102.5; Garden Valley Reach) where he reported: 

“The Umquah here is about 150 yards wide & runs over a rocky bottom of soft slatey rock & is not 

very deep. A horse can ford it at present.” 

The most extensive early survey was by U.S. Army Engineers lieutenant R.S. Williamson in 

1870 to investigate navigation possibilities. His report (U.S. House of Representatives, 1871) described 

the several bedrock rapids between Scottsburg and Roseburg and provided a general characterization of 

the river: 

“The average width of the river, when bankfull, appeared to be about 200 feet; but at its extreme 

low-water stage the water is divided at many places into half a dozen or more streams, varying in 

width from two to thirty feet, and separated from each other by walls of rock sometimes five or six 

feet in height. In passing though some of these narrow place[s] the velocity of the current was 400 

feet per minute. At each of these rapids between the channel and the shore there is a bench of 

sandstone, generally flat, varying from two to five feet in height above the low-water mark, and 

averaging about seventy-five feet in width. During ordinary stages of the river this is covered with 

water. The river contains no sand-bars, its bottom being coarse gravel, on solid bed-rock; 

consequently any improvements which may be made to the river are likely to be permanent.” 

A subsequent survey in 1910 encompassing most of the Roseburg, Garden Valley, and Coast 

Range Reaches by the Junior Engineer F.E. Leefe of the U.S. Engineer Office (U.S. House of 

Representatives, 1911) reiterates Williamson’s findings: 

“In the stretch of river under examination between Roseburg and Scottsburg, a distance of 86 miles, 

the low water fall is about 465 feet. Throughout this distance the river at low water is a succession 

of rocky rapids with pools of quiet water between, of varying lengths and depths. The river flows 

over a rocky sandstone bottom much of the way, with many dangerous reefs and projections. With 

such a fall, averaging nearly 51⁄2 per mile, the current is strong over the rapids at all stages.” 

Although sand and gravel accumulations are barely mentioned in many of these accounts of the 

South and mainstem Umpqua Rivers, except for noting their scarcity, some historical photographs show 
12

bars flanking the channel (fig. 4). We have found fewer early descriptions of the Days Creek Reach of 

the South Umpqua River at the time of first exploration, but it too was apparently locally flowing on 

bedrock, at least near its downstream end, because inchannel potholes near the Cow Creek confluence 

were targets for gold miners in the 1850s (Beckham, 1986, p. 93). 

Figure 4. Circa 1890s photograph of South Umpqua River upstream of Mount Nebo near Roseburg, Oregon. 

Courtesy Douglas County Museum (Photograph N5549a) 

Although no detailed surveys were conducted for the North Umpqua River, reports by the 

Wilkes Expedition on their 1841 overland trip between the Willamette Valley and San Francisco Bay 

(including geologist James Dwight Dana) state that the North Umpqua River ran on bedrock where they 

crossed it near the present location of Winchester (North Umpqua RM 7; Dana, 1849, p. 662). Similarly, 

Winterbotham, (2000, p. 133) noted: 

“The North Umpqua River has been pronounced, by experts in the driving of streams, to be the best 

driving stream in Oregon or Washington. It is singularly free from shifting sand bars and gravel 

shoals....” 

The character of the Tidal Reach was distinctly different; drifting sand and gravel bars caused 

persistent navigation problems between the mouth and the head of tide at Scottsburg (RM 27.5), leading 
13

to multiple bathymetric surveys beginning in the late 18th century (summarized by Beckham, 1986, p. 

149–152). These issues ultimately resulted in construction of the jetties and substantial and ongoing 

dredging of the lower channel. Shallow gravel bars in the vicinity of Brandy Bar (RM 20) also caused 

navigation hazards, and it was this area that ultimately became the reach of primary 20th and 21st

century sand and gravel mining by Umpqua River Navigation Company and its successors. 

Historical accounts also document channel and land-use practices that may have affected 

channel and bed-material conditions. These are most completely summarized in Beckham (1986) and

include navigational dredging and rock removal, gold mining, instream gravel mining, impoundment for 

hydropower, and forestry and other land-use practices. 

Historic navigation improvements were focused in the Tidal Reach, which has been the only 

section of river with extensive commercial boat traffic (Moser, 1976), but upstream reaches also had 

many rapids modified in the early 1870s in an attempt to promote navigation from the Pacific Ocean to 

Roseburg. Likewise, some bedrock rapids were modified in the late 19th century on both the South and 

North Umpqua Rivers to facilitate log drives (Beckham, 1986). 

Mill dams and other small obstructions also served various needs of early settlers, and later, 

larger dams have provided for hydropower and flood control. Of these early dams near Kellogg (RM 70; 

Coast Range Reach), Roseburg (RM 123; Roseburg Reach), and Winchester (North Umpqua RM 7), 

only the Winchester Dam, a 16-ft-high concrete structure on the North Umpqua River, remains, but it

probably does not significantly impede sediment movement. Pacific Power’s North Umpqua 

Hydroelectric Project was constructed during 1952–55 and now traps bedload from the upstream 32 

percent of the North Umpqua River basin. Sediment studies conducted in the late 1990s as part of 

relicensing these facilities are summarized later in this report. Galesville Reservoir on Cow Creek began 

filling in 1985, and since then has trapped all bed material from the upper 74.3 mi2

 of Cow Creek, 

encompassing 5.9 percent of the South Umpqua River basin at the Cow Creek confluence. 

Gold mining in the Umpqua River basin began in 1852 on the South Umpqua River near Riddle 

and in lower Cow Creek (Beckham, 1986, p. 225–226).The widespread placer mining on the South 

Umpqua River and its tributaries Olalla Creek (fig. 5; a tributary of Lookinglass Creek), Myrtle Creek, 

Cow Creek, and Coffee Creek (Diller, 1914; Ramp, 1972) probably had the most significant effects on 

instream gravel conditions. All these drainages enter the South Umpqua River within the Days Creek 

and Roseburg Valley Reaches. Placer mining in the late 19th and early 20th centuries involved 

extensive excavation of alluvial terraces flanking the present watercourses, in places aided by elaborate 

hydraulic works (fig. 5). Beckham (1986, p. 93) suggested tremendous effects to the stream channels 

from these activities: 

“Mining generated terrible problems for the Indians. The cascade of debris down the creeks and 

rivers had calamitous impact on the fish runs: mining destroyed the spawning grounds by washing 

away the gravels and coating the river bottom with mud.” 

Such effects, as well as the possibly tremendous inputs of gravel to South Umpqua tributaries, may still 

have important implications for the present-day sediment conditions in the Umpqua River system. 
14

Figure 5. Hydraulic mining in the Olalla District, Lookingglass Creek drainage, Oregon. Courtesy of 

Douglas County Museum (Photograph N5155), undated.

Compilation of Historical Maps and Survey Data

Beginning in the mid-19th century, the Umpqua River has been mapped and surveyed by 

multiple agencies, providing a potentially rich set of data that could be used to evaluate historical 

channel change. A limited set of maps and profile surveys developed by the General Land Office 

(GLO), USGS, and Army Corps of Engineers were reviewed in this study and are summarized in 

table 2. In reviewing the maps, we aimed to determine whether they provided information regarding

channel features (especially gravel bars) and bed elevations, and also to discern whether the map could 

be digitized for the purpose of conducting a future study comparing recent and historical channel 

morphology.
15

Table 2

Map title or description

. List of maps reviewed for this study of the Umpqua River basin, southwestern Oregon [GLO, General Land Office; BLM, Bureau of Land Management; NOAA, National Oceanographic and Atmospheric 

Administration; OSU, Oregon State University; USGS, U.S. Geological Survey; USACE, U.S. Army Corps of Engineers; 

DOGAMI, Oregon Department of Geology and Mineral Industries]

Map 

scale

Map 

date

Survey or 

Map 

Source Depository Description

General Land Office Surveys ~1:31,680 1853-

1890s

GLO maps BLM website:

http://www.blm.gov/or/

landrecords/survey/ySrvy1.

php; USGS (Portland, 

Oregon) has copies.

Earliest surveys conducted 1853-1858; 

most maps were meandered in 1853, 1874, 

and/ or 1891. Maps show planview of river 

channel and surrounding lands, limited 

details on river features.

Preliminary Survey of the 

Entrance to Umpquah River, 

Oregon

1:20,000 1854 United 

States 

Coast 

Survey

NOAA website:

http://historicalcharts.

noaa.gov/historical_jpgs/

CP436C.jpg 

Map of lower 5 miles of Umpqua River.

Profile surveys in 1914 in 

Umpqua River Basin. U.S. 

Geological Survey WaterSupply Paper 379

1:31,680 1914 USGS OSU library, Corvallis 

Oregon; USGS library, 

Portland, Oregon

Plan and profile of Umpqua River from 

Elkton to confluence of North and South 

forks and of North Umpqua to Boulder 

Creek, Oregon (11 sheets). Plan and 

profile of North Umpqua River from 

Boulder Creek to Diamond Lake (2 

sheets).

Map of Umpqua River, 

Scottsburg to Reedsport, 

Oregon

1:20,000 1921 USACE Photocopies at USGS 

(Portland, Oregon) and 

other locations.

Bathymetric map with low water 

soundings;.

Examination of Umpqua River, 

Oregon and entrance

Unknown 1925 USACE OSU library, Corvallis 

Oregon

Bathymetric map of lower 3 miles of 

Umpqua River 

Plan and Profile of Umpqua 

River above Scottsburg, North 

Umpqua River, and Tributaries

1:31,680 1926 USGS OSU library, Corvallis 

Oregon 

Document includes nine sheets of contour 

maps and longitudinal profiles.

Plan and Profile of South 

Umpqua River, Oregon, from a 

Point near Days Creek to Mile 

26 and Tributaries. Dam sites.

Varies 1938 USGS OSU library, Corvallis 

Oregon 

Contour map of South Umpqua from Days 

Creek area to Francis Creek, above Milo. 

Includes profiles. 

Plan and Profile map of Cow 

Creek, Oregon from Sec 2. T. 

32 S., R. 4 W to Sec. 2. T.32 

S., R.3 W. Dam Sites

1:24,000 1939 USGS OSU library, Corvallis 

Oregon 

Contour map of Cow Creek from Glendale 

area to Applegate Creek, including dam 

sites.

Report on Reexamination of 

Umpqua River and Harbor, 

Oregon

Unknown 1939 USACE OSU library, Corvallis

Oregon

Bathymetric map of lower 12 miles of 

Umpqua River; shows location of islands, 

bars, soundings etc. 

Plan Dam Sites, Smith River, 

Oregon

1:24,000 1958 USGS OSU library, Corvallis 

Oregon 

Planview of three dam sites on Smith 

River near Gardiner.

Plan Bradley Creek Reservoir 

and Dam Site North Umpqua 

River

1:24,000 1962 USGS OSU library, Corvallis 

Oregon

Planview contour map of Bradley Creek 

damsite. Also shows area and capacity 

curves.

Geologic Compilation Map of 

Douglas County, Oregon

1:250,000 1972 DOGAMI PDF available from 

DOGAMI, Portland, 

Oregon

Map shows major geological units and 

geomorphic divisions.

Flood profiles in the Umpqua 

River Basin, Oregon (three

parts)

Varies 1972, 

1973, 

1975

USGS USGS library, Portland, 

Oregon

Series of three reports (Oster, 1972; 1973; 

1975) provide cross-sections and flood 

profiles for Umpqua, North Umpqua, and 

South Umpqua Rivers and selected 

tributaries. Elevation data from 

orthophotography and soundings.
16

A series of USGS flood studies (Oster, 1972; 1973; 1975) and early navigational surveys 

completed by the U.S. Army Corps of Engineers produced maps that potentially provide useful 

information. The USGS flood studies provide longitudinal profiles and cross-sections for the Umpqua 

River, South Umpqua River, North Umpqua River, and select tributaries. The USGS data were

originally used for flood modeling, but could provide baseline topographic information for evaluating 

systemwide changes in channel geometry from the 1970s to present. The navigational surveys from the 

late 19th and early 20th centuries primarily cover the tidal reach of the Umpqua River where navigation 

improvement efforts were focused. Depending on the availability, extent, and data quality of additional 

navigational surveys not reviewed in this study, it may be possible to compile a set of maps covering the 

Tidal Reach (RM 0–27.5) that span several decades in the time period 1850–1920. Such maps could be 

used to evaluate changes in bed elevation in the early phases of European-American occupation in the 

Umpqua River basin and may help to place 20th century bathymetric changes in a greater historical 

context, possibly revealing longer term patterns of incision and aggradation in the lower reaches of the 

Umpqua River.

Assessment of Aerial Photographs

We reviewed aerial photograph collections from the Corps of Engineers library in Portland and

the University of Oregon library in Eugene, as well as digital orthophotographs available from online 

sources (table 3). Additional aerial photographs not included in this review are likely available from the 

Bureau of Land Management, National Archives, and other sources. 

Table 3. List of aerial photographs reviewed for this study of the Umpqua River basin, southwestern 

Oregon—continued

[USACE, U.S. Army Corps of Engineers; UO, University of Oregon; USDA, U.S. Department of Agriculture; USGS, 

U.S. Geological Survey; OR DOR, Oregon Department of Revenue; BLM, Bureau of Land Management; NAIP, 

National Agriculture Imagery Program]

Year Area covered Scale Source Current location

Umpqua River, river mile 0–112

1939 Mouth to Reedsport 1:20,000 USACE UO Library

1939 Nearly complete Quads for 

Reedsport to Elkton

1:10,200

USACE USACE, Portland District

1939 Elkton upstream 1:20,000 USDA UO Library

1942 Mouth to upstream of Scottsburg 1:20,000 USGS UO Library

1943 Elkton to Myrtle Creek 1:20,000 USACE UO Library

1944

Mouth to Reedsport

1:15,000/

1:30,000 USACE USACE, Portland District

1950 Full coverage 1:20,000 USGS UO Library

1952 Mouth to Elkton 1:20,000 USDA UO Library

1956–57 Nearly complete coverage RM 

8–16 

various

USACE USACE, Portland District

1957 Partial coverage in RM 8–16, 

RM 24–33 and RM 45–49

1:9,600/

1:24,000 USACE USACE, Portland District

1960 Downstream of Elkton to points 

upstream

1:20,000

USDA UO Library

1963 Mouth to Reedsport various USACE USACE, Portland District

1963–64 Downstream of Elkton 1:14,400 USACE USACE, Portland District
17

Table 3. List of aerial photographs reviewed for this study of the Umpqua River basin, southwestern 

Oregon—continued

[USACE, U.S. Army Corps of Engineers; UO, University of Oregon; USDA, U.S. Department of Agriculture; USGS, 

U.S. Geological Survey; OR DOR, Oregon Department of Revenue; BLM, Bureau of Land Management; NAIP, 

National Agriculture Imagery Program] 

Year Area covered Scale Source Current location

Umpqua River, river mile 0–112

1965 Nearly complete coverage various USACE USACE, Portland District

1967 Full coverage 1:20,000 USDA UO Library

1969 Downstream of Elkton 1:20,000 OR DOR UO Library

1973 Downstream of Roseburg to 

mouth of N. Umpqua River

1:20,000

OR DOR UO Library

1974–75

Mouth to Reedsport

1:24,000/

1:2,400 USACE USACE, Portland District

1977 Mouth to Reedsport 1:15,000 USACE USACE, Portland District

1978 Mouth to Scottsburg 1:12,000 USACE USACE, Portland District

1978 Scottsburg area (RM 24 to RM 

33) 

1:24,000

USACE USACE, Portland District

1979 Points: near Reedsport, Elkton, 

near Roseburg and Myrtle Creek

1:20,000

USDA UO Library

1980 Gardiner area (RM 8 to RM 16) 1:12,000 USACE USACE, Portland District

1980 Mouth to Scottsburg 1:20,000 USGS UO Library

1980 Mouth to Scottsburg 1:12,000 USACE USACE, Portland District

1982 Gardiner area (RM 8 to RM 16) 1:24,000 USACE USACE, Portland District

1982 Nearly complete coverage 1:48,000 USACE USACE, Portland District

1984 Point near Elkton 1:20,000 USGS UO Library

1985 Downstream of Elkton to Tyee 

area

1:20,000

BLM UO Library

1986 Partial coverage near Scottsburg, 

Elkton, and Tyee 

1:48,000

USACE USACE, Portland District

1989 Tyee area (RM 81 to RM 100) 1:24,000 USACE USACE, Portland District

1989 Elkton to Roseburg 1:20,000 BLM UO Library

1989 Scottsburg area (RM 24 to RM

33)

1:12,000

USACE USACE, Portland District

1989 Full coverage 1:24,000 USACE USACE, Portland District

1995 Full coverage 1:20,000 USGS http://edcns17.cr.usgs.gov/EarthExplorer/

2000 Full coverage 1:20,000 USGS http://edcns17.cr.usgs.gov/EarthExplorer/

2001 Scottsburg downstream 1:24,000 USACE USACE, Portland District

2001 Coverage from RM 8 to RM 16 1:24,000 USACE USACE, Portland District

2002 Partial coverage Tyee upstream 1:24,000 USACE USACE, Portland District

2003 Coverage from RM 8 to RM 16 1:2,400 USACE USACE, Portland District

2004 Full coverage 1:20,400 Douglas 

County

Douglas County

2005 Full coverage 1:20,000 USDA http://www.oregonexplorer.info/imagery/

about/about.aspx?Res=17270
18

Table 3. List of aerial photographs reviewed for this study of the Umpqua River basin, southwestern 

Oregon—continued

[USACE, U.S. Army Corps of Engineers; UO, University of Oregon; USDA, U.S. Department of Agriculture; USGS, 

U.S. Geological Survey; OR DOR, Oregon Department of Revenue; BLM, Bureau of Land Management; NAIP, 

National Agriculture Imagery Program] 

Year Area covered Scale Source Current location

North Umpqua River, river mile 0–36

1939 Mouth to Glide 1:20,000 USDA UO Library

1950 Full coverage 1:20,000 USGS UO Library

1953 Myrtle Creek to River Forks 1:20,000 USDA UO Library

1954 Coverage from Brockway Gage

to Myrtle Creek 

1:20,000 USDA UO Library

1957 Full coverage 1:96,000 USACE USACE, Portland District

1960 Full coverage 1:20,000 USDA UO Library

1965 Nearly complete coverage 1:24,000 USACE USACE, Portland District

1967 Full coverage 1:20,000 USDA UO Library

1973 Point near Winchester 1:20,000 OR DOR UO Library

1979 Points: near Winchester 1:20,000 USDA UO Library

1982 Mouth to Winchester 1:48,000 USACE USACE, Portland District

1985 Full coverage 1:20,000 BLM UO Library

1995 Full coverage 1:20,000 USGS http://www.oregon.gov/DAS/EISPD/GEO/

data/doq.shtml

2000 Full coverage 1:20,000 USGS http://edcsns17.cr.usgs.gov/EarthExplorer/

2002 Full coverage 1:24,000 USACE USACE, Portland District

2004 Full coverage 1:20,400 Douglas 

County

Douglas County

2005 Full coverage 1:20,000 NAIP http://165.221.201.14/NAIP.html

South Umpqua River, river mile 112–192

1939 Mouth to Tiller 1:20,000 USDA UO Library

1950 Full coverage 1:20,000 USGS UO Library

1953 Mouth to point downstream of 

Tiller

1:20,000 USDA UO Library

1957 Full coverage Varies USACE USACE, Portland District

1960 Full coverage 1:20,000 USDA UO Library

1965 Full coverage 1:24,000 USACE USACE, Portland District

1967 Full coverage 1:20,000 USDA UO Library

1968 Full coverage above Days Creek 1:40,000 USACE USACE, Portland District

1971 Full coverage 1:20,000 BLM UO Library

1977 Partial coverage: Canyonville, 

Days Creek to Tiller

1:4,800 USACE USACE, Portland District

1979 Points near Canyonville 1:20,000 USDA UO Library

1982 Full coverage 1:48,000 USACE USACE, Portland District

1985 Full coverage 1:20,000 BLM UO Library

1986 Full coverage 1:48,000 USACE USACE, Portland District

1989 Full coverage 1:24,000 BLM UO Library
19

Table 3. List of aerial photographs reviewed for this study of the Umpqua River basin, southwestern 

Oregon—continued

[USACE, U.S. Army Corps of Engineers; UO, University of Oregon; USDA, U.S. Department of Agriculture; USGS, 

U.S. Geological Survey; OR DOR, Oregon Department of Revenue; BLM, Bureau of Land Management; NAIP, 

National Agriculture Imagery Program] 

Year Area covered Scale Source Current location

South Umpqua River, river mile 112–192

1995 Full coverage 1:20,000 USGS http://edcsns17.cr.usgs.gov/EarthExplorer/

2000 Full coverage 1:20,000 USGS http://edcsns17.cr.usgs.gov/EarthExplorer/

2002 Full coverage 1:24,000 USACE USACE, Portland District

2004 Full coverage 1:20,400 Douglas 

County

Douglas County

2005 Full coverage 1:20,000 NAIP http://165.221.201.14/NAIP.html

Several sets of aerial photographs are available that cover most or all of the study area. Along 

the alluvial reaches of the North and South Umpqua Rivers, including the Roseburg, Days Creek, and 

North Umpqua Reaches, there is nearly complete aerial photograph coverage every 1–10 years from 

1939 to 2005. The Tidal Reach of the mainstem Umpqua River (RM 0–27.5) also has frequent aerial 

photograph coverage, but the reach from Elkton to the confluence of the North and South Umpqua (RM 

48.5–112; the Coast Range and Garden Valley Reaches), has sparser coverage, both in terms of the 

temporal frequency of the photographic sets and their spatial coverage. Photographic sets from 1939, 

1950, 1967, and several more recent years apparently cover the entire study area. In summary, these 

collections of aerial photographs could provide a solid basis for documenting historic changes to 

channel and gravel bar conditions, although such analyses might not reveal changes resulting from 

recent changes in land-use practices because of lengthy response-time lags. 

Review of Water- and Sediment-Related Studies in the Umpqua River Basin

We also reviewed previous studies of hydrology and sediment transport that have been 

conducted in the Umpqua River basin. Although there are numerous studies peripherally related to bedmaterial supply and transport (such as turbidity and other water-quality studies), we focused on two 

studies directly relevant to issues of gravel transport and channel morphology in the study area: (1) the 

basinwide analysis of sediment transport by Curtiss (1975), and (2) the sediment transport analyses

conducted by Stillwater Sciences (2000) in support of the FERC relicensing of the Pacific Power 

hydroelectric facilities on the North Umpqua River.

The Curtiss (1975) report builds on an earlier USGS report by Onions (1969) by providing 

estimates of annual suspended-sediment discharge for 11 sites in the Umpqua River basin based on as 

many as 18 years of suspended-sediment measurements between 1956 and 1973. Although there were 

no measurements of bedload in this study, Curtiss (1975) calculated total sediment loads (bedload plus 

suspended load) on the basis of measurements at Flynn Creek (a Coast Range stream in the Alsea River 

basin) where bedload constituted 3 percent of the mean annual suspended-sediment yield. This ratio was 

applied for the sites in the Umpqua River basin, except for Cow Creek, where field observations led to 

the inference that bedload composed 5 percent of the total load. Although no known bedload 

measurements for the Umpqua River system substantiate these values, bedload transport rates typically 

scale with suspended load, and the analysis by Curtiss (1975) probably provides a reasonable guide to 

the relative contributions of bed material to the Umpqua River system. For the mean annual total

sediment discharge of 1.7×106

 tons/yr of the South Umpqua River (at Brockway), the Curtiss (1975) 

analysis indicates that 0.31×106

 tons/yr enters via Lookingglass Creek, 0.37×106 tons/yr joins at Cow 
20

Creek, and 0.14×106 tons/yr comes from the upper watershed upstream of the Tiller gaging station. 

These values suggest that more than 90 percent of the sediment entering the South Umpqua River is 

derived from tributaries joining downstream of Tiller. At the Elkton streamflow-gaging station on the 

mainstem Umpqua River, where 3.5×106 tons/yr of sediment passes each year, 23 percent is from the 

North Umpqua River (0.80×106 tons/yr at Winchester), 49 percent from the South Umpqua River at 

Brockway (1.7×106 tons/yr), 5 percent from the Calapooya (0.19×106 tons/yr), with the balance likely

from the lower South Umpqua River and unmeasured tributaries entering the mainstem Umpqua River 

between the confluence of the North and South Umpqua Rivers and the Elkton streamflow-gaging 

station. These results point to the overall greater contribution of sediment to the Umpqua River system 

by the South Umpqua River. The data could also serve as a basis for a calibrated model of basin 

sediment production similar to that done for the Deschutes River basin in central Oregon (O’Connor and 

others, 2003). 

Stillwater Sciences (2000) prepared sediment budgets for the North Umpqua River to assess the 

role of Pacific Power’s North Umpqua River hydroelectric project on North Umpqua River sediment 

conditions. Their analysis incorporated a reanalysis of the suspended load data summarized by Curtiss 

(1975), analysis of reservoir sedimentation data, estimates of geomorphic process rates, landslide 

inventory information, and GIS analyses. They concluded that the dams on the North Umpqua River 

trap all bedload from the upper 32 percent of the North Umpqua River basin but the effects of this bedmaterial sediment reduction on downstream reaches are more than compensated by enhanced sediment 

production owing to 20th century land-use practices—primarily forest practices—and the effects of the 

1964 flood. Specifically, Stillwater Sciences (2000) postulated that downstream of Steamboat Creek, at 

North Umpqua RM 49.2, the effects of land use doubled the average annual bedload flux to 18,000 

tons/yr , from a “reference condition” (pre-1950, minimal land-use effects) value of less than 9,000 

tons/yr, despite total bed-material blockage since 1952 at Soda Springs Dam at RM 69.3. Although 

these conclusions for the North Umpqua River remain unverified, the possibility of enhanced bed 

material contributions to the Umpqua River system from increased sediment yield in managed lands 

basinwide would need to be addressed for comprehensive understanding long-term bed-material supply 

and transport conditions. 

Review of Gravel-Operator Surveys

Survey data for 2001–03 through June 2008 for six instream gravel mining sites along the South 

Umpqua River in the Roseburg and Days Creek reaches were provided by Umpqua Sand and Gravel 

Inc. and Knife River/LTM Inc. (IE Engineering, written commun., 2008). Surveyed cross-sections and 

longitudinal profiles for the Tidal Reach of Umpqua River near the LTM Inc. dredging at RM 19–22 

were provided by Lidstone and Associates and also were included in correspondence provided by Janine 

Castro (U.S. Fish and Wildlife Service; written commun., 2008). Although the South Umpqua River 

mining surveys reviewed in this study (fig. 6) are incomplete and represent just a portion of the total 

permitted gravel extraction occurring in the Umpqua River basin, they do show the evolution of 

individual gravel bars in the years following gravel extraction.
21

Figure 6. Summary of gravel bar volume changes, 2000–2008, at instream gravel mining sites along 

the South Umpqua River, southwestern Oregon. Data from surveys provided by IE Engineering, 

Roseburg, Oregon (written commun., 2008). For sites with missing surveys, cumulative totals assume 

no net change for period of missing data. Mean monthly and annual (water year) peak flows are from 

USGS data for streamflow-gaging station South Umpqua River near Brockway, station 14312000. 
22

Survey information for the six sites of gravel bar mining on the South Umpqua River show that 

removal volumes in 2001–04 ranged up to 13,390 yd3

 but typically were less than 10,000 yd3 per year at 

each site. From these records and communication with individual operators, none of the analyzed bars 

have been mined after 2004. Since then, each of the six bars has accumulated gravel, with four of the six 

bars now showing positive balances relative to the original provided survey (and it is possible the 

Weigle Bar also has had a net accumulation because survey data spanning the 2006 high flow was not 

available). Deposition volumes are most easily assessed for 2004–08, during which there was no mining

and all changes to bar volumes resulted from fluvial erosion and deposition. Nearly all bars grew 

significantly (aggrading as much as 2 ft) during the winter of 2005–06, in conjunction with high flows, 

including the Dec. 31, 2005, peak of 73,400 ft3

/s—the highest peak flow on the South Umpqua River 

since December 1996. The only bar that clearly has not regained the volume of sediment documented in 

the first survey is Days Creek bar at RM 172. In all cases, the net changes in volumes, averaged over 

our mapping of bar area, total less than 1 ft of bar-surface elevation change. 

These surveys on the sites on the South Umpqua River show that active gravel transport by the 

river tends to rebuild the forms of mined gravel bars, especially after large flows and multiple years of 

no mining. But because these mined gravel bars have enhanced depositional space resulting from 

excavation, they are likely to preferentially accumulate gravel after mining and the survey results can 

not be used directly to determine long-term gravel accumulation or flux rates, although the survey data 

for the last few years may help provide bounds for such determinations. Also, since the first surveys 

post-date a long history of mining at many of these bars, long-term trends of bar changes and current bar 

status relative to undisturbed conditions cannot be determined directly from the surveys, although 

cursory analysis of systematic changes in bar area (described below) also indicates little overall change

during 1939–2005. Nevertheless, extraction of gravel from these bars—in some years totaling more than 

35,000 yd3

 for the six bars evaluated here—certainly reduces the overall flux of bed material through 

the river. Whether or not such volumes are significant relative to the overall bed-material transport and

therefore affect long-term channel conditions for these reaches and downstream remains unanswered. 

The Tidal Reach between RM 0 and 27.5 has experienced substantial bed-sediment removal to 

maintain navigation depths in the channel and for sand and gravel aggregate, summing to more than 1.2 

million yd3 for 1949–2002 (fig. 7). The main area of aggregate removal has been between RM 19 and 

22, where extraction has averaged about 175,000 yd3/yr by the Umpqua River Navigation Company and 

its successors. Targeted analyses of the reach of aggregate mining in the 1970s (CH2M-Hill, 1971) and 

subsequently by Lidstone and Associates (written commun., 2008) and Janine Castro (U.S. Fish and 

Wildlife Service, written commun., 2008) also furnish repeat cross sections, channel soundings and 

thalweg profiles. Inspection of these data indicate that this reach is dynamic, with areas of deepening 

and shoaling, but that the general trends for most time sequences is channel deepening along the 

thalweg, locally as much as 5 ft, with areas of dredging not being refilled. In the case of the 1971 

CH2M-Hill analysis, excavations in areas not mined for more than 5 years had not been refilled. Our 

preliminary interpretation of these observations is that the supply of bed material is less than the 

175,000 yd3 average annual bed-material removal rate. This value, however, is not directly comparable 

with bed-material transport values for other reaches because the much lower channel gradient of the 

Tidal Reach probably results in a larger proportion of the upstream derived sediment load—which is 

primarily transported as suspended load—becoming bedload in this reach of lower flow velocities and 

channel gradient. 
23

Figure 7. Excavation volumes for 1949–2002, for the Umpqua River Navigation (and successor 

companies) mining site along lower Umpqua River below RM 27, southwestern Oregon. Volumes for 

1949–71 as reported by CH2M HILL (1971); Volumes for 1971–2002 from Umpqua River Dredging 

reports, as supplied by Lidstone and Associates (written commun., 2008).

Compile and Review Oregon Department of Transportation Umpqua River Bridge Inspection 

Reports

The Oregon Department of Transportation conducts routine inspections on bridges which

provide information that is potentially useful in characterizing channel change at the bridge location. 

We reviewed 35 reports for inspections conducted between 2002 and 2008 for bridges crossing the 

Umpqua River, North Umpqua River, and South Umpqua River (Oregon Department of Transportation, 

written commun., 2008). For each of these, we evaluated the underwater reports, scour assessments, 

photographs, and any other notes or cross-section data providing an indication of incision or 

aggradation. 

For nearly all bridges evaluated in the 35 bridge inspection reports we reviewed, all bridge piers 

have been set in bedrock. Although most piers show some scour near the footings, there were only three 

reports that describe substantial bedrock erosion near the piers. Cross-section data from multiple time 

periods were available for eight bridges within the study area. For six of these bridges, net change in 

thalweg elevation over time has been minimal, whereas at two locations, thalweg elevations have 

increased. The channel under the Highway 101 bridge near RM 11 on the Umpqua River (near the 

Smith River confluence in the Tidal Reach) aggraded about 5 ft between 1999 and 2006, and South 

Umpqua River under the I-5 bridge near Roseburg (RM 122) aggraded about 2 ft between 2000 and 

2005. In summary, the bridge inspection reports reviewed so far do not indicate significant channel 

changes that can be linked to changes in sediment supply, primarily because most bridge crossings were 

located where piers could be placed directly into bedrock. The local degree of bedrock erosion near 

some of these piers, however, attests to the softness of local rock types, which might be an important 

factor in the apparent downstream decrease in gravel along the Umpqua River, particularly downstream 

of the confluence of the North and South Umpqua Rivers. More extensive research of the bridge 

inspection reports will not likely provide much useful information. 

Specific Gage Analysis

Following the approach of Klingeman (1973), a specific gage analysis was completed for three 

USGS streamflow-gaging stations in the study area. The purpose of the specific gage analysis is to 

detect changes in streambed elevation by assessing changes in water elevation (stage) through time for a 
24

set of discharge values. At USGS streamflow-gaging stations, discharge is related to stage by a stagedischarge rating curve, which is based on multiple simultaneous measurements of stage and discharge. 

If channel conditions change substantially (as evidenced by consistent offsets of newer measurements 

from established rating curves), or if a station is moved, a new rating curve will be developed. The 

specific gage analysis evaluates trends as indicated by the sequence of rating curves for individual 

stations while they are at specific locations. For this study, we examined the sequence of USGS rating 

curves at three sites (fig. 8): the mainstem Umpqua River near Elkton (14321000), the South Umpqua 

River near Brockway (14312000), and the North Umpqua River at Winchester (14319500). Because the 

purpose of this task was to detect potentially small changes in bed elevation, we assessed changes in 

flow stage for low to moderate flows (500–10,000 ft3/s), which are more sensitive to minor adjustments 

in bed elevation and are less likely to be influenced by temporal changes in bank vegetation or changes 

in bank shape. 
25

Figure 8. Sequence of stage-discharge rating curve elevations for specific discharges for long-term 

mainstem streamflow gages in Umpqua River, Oregon, study area. Source information from station 

records housed at Oregon Water Science Center, U.S. Geological Survey, Portland, Oregon.

The specific gage analysis (fig. 8) shows that all three sites have experienced minor changes in 

stage over the period for which flow data are available. At the Umpqua River station near Elkton, the 

gage location has changed four times over the period 1906–2008, and stage remained stable while at 

each location. For 1906–57, stage for each discharge varied by less than 0.4 ft, whereas during 1957–72, 

stage at 500 ft3

/s decreased by approximately 0.7 ft. This degradation may have resulted from local 
26

scouring of bed material, possibly associated with the 1964 flood. For 1972–2008, stage for all 

discharges remained nearly constant, indicating negligible change in bed elevation. 

The gage analysis for the North Umpqua River at Winchester spans two time intervals: 1924–30 

and 1955–2008. For all discharges, and across both time periods, measured stage varied by less than 0.4 

ft, indicating that the bed elevation at the Winchester gaging station has remained fairly constant over 

the period of measurement. 

The South Umpqua gaging station near Brockway provides data for three periods: 1906–12, 

1924–28, and 1942–2008. For all three time periods, the Brockway gage displays little to no change in 

stage for the discharges used in this analysis. For 1942–2008, the net change for 500 and 1,000 ft3/s is 

on the order of 0.2 ft, which indicates that the bed elevation at this site has remained fairly constant over 

time.

Mapping of Gravel Bars and Channel Features 

Two mapping efforts were undertaken in order to identify spatial and temporal patterns in gravel 

bar location and size throughout the study area. As a first step, all river-flanking sediment 

accumulations throughout the study area were mapped and digitized from the 2005 National Agriculture 

Imagery Program (NAIP) orthophotographs at a scale of approximately 1:5,000 (fig. 9). For all study 

reaches except for the Tidal Reach, these areas consisted of gravel bars or patches of sand and gravel 

adjacent or within the channel. For the Tidal Reach, mapped accumulations included sand and gravel 

bars as well as extensive mud and tidal flats in the estuary. A more detailed mapping effort was 

conducted for five short reaches in order to evaluate possible temporal changes in gravel bar area. 

Figure 9. Distribution and size of fluvial sediment accumulations in the Umpqua River, southwestern Oregon, study 

area as mapped from 2005 National Agriculture Imagery Program aerial photographs at a scale of ~1:5,000. Within 

the Tidal Reach (RM 0–27.5), mapped areas consists primarily of extensive vegetated mud flats; elsewhere, 

mapped areas are primarily gravel bars. For plotting purposes, river miles for the North Umpqua Reach (RM 0–36)

have been added to the Umpqua River at the confluence of the North and South Umpqua Rivers (RM 111.8).
27

The broad-scale mapping 

for the entire study area shows 

that most numerous gravel bar 

deposits are along the South 

Umpqua River, especially the 

Roseburg Valley Reach, where 

both the frequency and size of 

gravel bars exceed gravel deposits 

on the North Umpqua and 

mainstem Umpqua Rivers (except 

the Tidal Reach) by at least a 

factor of two (fig. 10; table 1). 

From the confluence of the North 

and South Umpqua Rivers 

downstream, the frequency of 

gravel bars diminishes and sand 

and gravel accumulations are 

sparse. An exception is Maupin 

Bar at RM 63, with an area of 38 

acres (153,000 m2

), which stands 

out at about 10 times larger than 

other bars along the Coast Range 

Reach of the Umpqua River. 

Although the Tidal Reach has 

several very large sediment 

accumulations within and 

flanking the channel, these 

features are chiefly mud and sand 

flats and are not directly 

comparable with the gravel bars 

upstream. Findings from the bar 

mapping are corroborated by our 

field observations, which revealed 

only rare gravel deposits along 

the mainstem Umpqua River, 

even at the heads of rapids and 

insides of meander bends where 

gravel deposits typically

accumulate in rivers of this size 

and gradient. 

Figure 10. Mapped bar areas for selected reaches of the Umpqua 

River basin, southwestern Oregon, from aerial photographs dated 

1939, 1967, and 2005.
29

The systematic decline in the frequency and size of gravel bars from the South Umpqua River 

through the Garden Valley and Coast Range Reaches must owe to (1) downstream reduction of bedmaterial fluxes (due either to particle abrasion or inchannel storage) or (2) recent acceleration of bedmaterial supply to the South Umpqua River that has not yet made it downstream. 

To determine whether there were obvious temporal trends that might partly explain the 

distribution of gravel bars, we selected five sites for detailed mapping from repeat sets of aerial 

photographs: the lower Umpqua River (RM 8–13; Tidal Reach), Tyee (RM 80–81; Coast Range Reach), 

Cleveland Rapids (RM 107.5–110.5; Garden Valley Reach), South Umpqua River (RM 128–132; 

Roseburg Reach) and North Umpqua River (RM 9–12.5). For each site, we scanned and rectified aerial 

photographs from 1939 and 1967 to supplement the existing 2005 NAIP orthophotographs. Digitization 

for the detailed mapping was conducted at 1:3,000 for all sites except for the much larger lower 

Umpqua reach, which was digitized at a scale of 1:10,000. The detailed mapping entailed digitizing the 

wetted channel, gravel bars and active channel boundary. Gravel bars were further subdivided into 

vegetated and unvegetated areas, where unvegetated was considered to be areas with less than 20 

percent vegetative cover. Although ancillary datasets, such as the 1:24,000 USGS topographic maps and 

the 1995 and 2000 USGS orthophotographs, were used to aid in the identification of gravel bars, these 

results should be considered preliminary, because it is difficult in some instances to distinguish bedrock 

shoals capped by a thin veneer of gravel from thicker “bar-like” deposits of gravel. 

The historical channel mapping shows no systematic trends in bar area or channel for 1939–2005 

(figs. 10–15). Several locations had decreased bar area between 1939 and1967, which likely was due to 

erosion by the 1964 flood. At the Tyee site (fig. 11), a large midchannel bar feature eroded between

1939 and 1967, followed by bar growth between 1967 and 2005. Similarly, the bar at RM 109 in the 

Cleveland Rapids photograph site (fig. 12) was present in the 1939 photographs, was absent in 1967 and 

then reappeared with larger area by 2005. The largest changes in channel morphology were near RM 

130 on the South Umpqua River, where the channel avulsed around a large midchannel island between 

1939 and 1967 (fig. 13). Gravel bars at the North Umpqua River photograph site (fig. 14) increased in 

area and frequency 1939–67, but many of these newly deposited surfaces appeared vegetated, inactive 

or were eroded by 2005, resulting in a decrease in bar area. At nearly all bars mapped between 1939 and 

2005, losses in bar area 1939–67 are coupled with decreases in the vegetated bar area, and aerial

photographs show that many of the vegetated bars present in the 1939 photographs were bare gravel in 

the 1967 photographs, probably owing to the high flows of 1964. 
30

Figure 11. Mapped channel and bar features for the Umpqua River at Tyee 

site, southwestern Oregon, 1939–2005. 
31

Figure 12. Mapped channel and bar features for the Umpqua River at Cleveland Rapids site (RM 107.5–110.5), 

southwestern Oregon, 1939–2005.

Figure 13. Mapped channel and bar features at the South Umpqua River site (RM 128–132), southwestern 

Oregon, 1939–2005. 
32

Figure 14. Mapped channel and bar features at the North Umpqua River site (RM 9–12.5), southwestern 

Oregon, 1939–2005.

The lower Umpqua River photograph site (fig. 15) was the only location that displayed 

systematic increases in the area of bars and island. However, the bars and islands mapped in this tidal 

reach are likely composed of sands and fine sediments, and are not active gravel bar surfaces like those 

observed along the fluvial reaches. The large islands in this reach remained fairly stable in terms of their 

overall shape, but did grow in size, especially near RM 9–11 downstream of the Smith River 

confluence. 

From this preliminary analysis, the primary conclusion is that these bars are dynamic features 

acting as a source and sink for bed material in a manner apparently related to recent flow history. More 

systematic mapping for longer reaches and more time intervals would be required for documenting 

longer term temporal and longitudinal trends. Such mapping would also be a basis for morphologybased transport rates similar to those conducted on other Western rivers (see, for example, Ham and 

Church, 2000). 
33

Figure 15. Mapped channel and bar features at the Lower Umpqua River site (RM 8–13), southwestern Oregon, 

1939–2005.

Gravel Bar Particle Size Analyses 

During the November 2008 site visit, we measured surface particle-size distributions at five 

gravel bars in the study area: Umpqua River near Cougar Creek (RM 93; Coast Range Reach), Umpqua 

River near Cleveland Rapids Bar (RM 109; Garden Valley Reach), South Umpqua River at Umpqua 

Sand and Gravel Bar (RM 115.2; Roseburg Reach), South Umpqua River at Days Creek Bar (RM 172; 

Days Creek Reach), and two surface measurements at North Umpqua River near Singing Waters Road 

(RM 9.2 and RM 9.5). Measurements of particles on the bar surface were determined using Wolman 

(1952) pebble count methodology and gravelometer (a measurement template), which allows for the 

rapid, standardized measurement of clasts greater than 2 mm in diameter. To determine particle size for 

the subsurface layer of gravel bars, we took bulk samples from the bar apex at four of the six sites where 

surface measurements were conducted. These bulk samples were analyzed for size distribution by the 

USGS sediment laboratory in Vancouver, Washington. 

Plots of particle-size data (fig. 16) indicate that the bar subsurface is finer than the surface layer.

A coarse surface layer (or armoring) is typically observed on gravel-bed rivers, and can result from the 

selective scouring of fines or selective deposition of large particles (Bunte and Abt, 2001). The degree 

of armoring is indicated by the ratio of the D50 (median grain size) of the surface layer to the D50 of 

subsurface layer. For rivers with a high sediment supply, this ratio is typically close to 1, whereas for 

rivers where the transport capacity exceeds sediment supply, bar surfaces become armored and will 

have armoring ratios approaching 3 in the extreme case of energetic rivers with little or no sediment 

supply (Bunte and Abt, 2001). Armoring ratios determined for the Umpqua River show that transport 
34

capacity may significantly exceed sediment supply at the North Umpqua River and Cleveland Bar 

(mainstem Umpqua River) sites where D50 surface/D50 subsurface is approximately 1.9 and 1.83, respectively.

By contrast, the two sites on the South Umpqua River—Umpqua Sand and Gravel location and the Days 

Creek site—both have lower armoring ratios of 1.13 and 1.25, respectively, potentially indicating that 

sediment supply more closely approximates with transport capacity. These results are consistent with 

the greater area and abundance of gravel bars on the South Umpqua River, although the widespread 

presence of channel bedrock indicates that transport capacity at least marginally exceeds supply for the 

South Umpqua River. For all reaches, subsequent such analyses will require careful sampling to avoid 

areas of recent gravel mining or recreational disturbance, so that the measured armoring ratios reflect 

actual transport and sediment supply conditions. 

Comparison of particle-size data from all sites (fig. 16) show that coarsest surface layers were 

measured at the two Umpqua River sites (Cleveland Bar and Cougar Creek Bar) and the South Umpqua 

River at Days Creek Bar. The two North Umpqua River sites were located at the upstream and 

downstream ends of a long (0.3 mi) bar that extended alongside a bedrock rapid. Although the bar 

surface at the downstream site is coarser than the upstream site, this probably is due to its position at the 

base of the rapid, whereas the finer upstream site was located near a pool, upstream of the rapid, 

indicating the important role of local site conditions on depositional patterns and bed-material size. 

Because particle size was measured at only six sites, which span more than 90 river miles and 

three rivers, it is difficult to determine longitudinal trends such as downstream fining. Although 

additional data are needed to draw more conclusive findings, it does appear that grain size decreases 

along the length of the South Umpqua River from the Days Creek site (RM 172) to the Umpqua River 

Sand and Gravel site (RM 115). Measurements from the two mainstem Umpqua River sites suggests 

that gravel bars may coarsen downstream of the confluence with the North and South Umpqua Rivers, 

perhaps indicating local sediment sources, but additional data are needed to confirm this trend. 

Additional particle-size measurements, as well as assessment of rock types composing the gravel bars, 

could significantly aid in determining key aspects of the sediment budget by providing quantitative 

measures of sediment source areas, downstream fining, and downstream changes in transport capacity 

relative to sediment supply. 
35

Figure 16. Particle-size distribution for gravel bars In the North Umpqua River basin, southwestern Oregon, 

sampled during a November 2008 field reconnaissance. A. Subsurface and surface comparisons for four sampled 

bars. Surface size distribution measured by Wolman (1952) count of 100 clasts; subsurface distribution from bulk 

sample below armor layer of approximately 100 pounds. B. Comparison of bar surface grain size distributions for 

six bars. N., North; S., South; R. River.
36

Summary of Findings

On the basis of field observations and datasets reviewed in this study, the Umpqua River above 

river mile (RM) 27.5 flows mostly on bedrock, indicating that the river is in a long-term (over timescales of thousands of years) state of incision. This is most likely a response to ongoing uplift of the 

Coast Range and adjacent terrains in response to regional geologic forces. Furthermore, many reaches of 

the Umpqua River system have relatively few gravel bars, and historical documents indicate that these 

same reaches were gravel-poor in the 19th and early 20th centuries. The extensive presence of inchannel 

bedrock, combined with a paucity of gravel bars, indicates that the Umpqua River upstream of the Tidal 

Reach was historically, and still is, sediment supply limited—meaning that transport capacity exceeds 

the volume of sediment entering the river system. Nevertheless, the South Umpqua River contains 

distinctly more abundant gravel bars, and operator surveys indicate that these gravel bars are dynamic 

features—replenished and locally eroded by high flows. 

Although there are more gravel bars in the South Umpqua River, especially downstream of the 

Cow Creek confluence, it is unclear what happens to this gravel once it enters the mainstem Umpqua 

River downstream of the confluence of the forks. Specific gage analyses, temporal changes in bar area, 

and other information reviewed in this study do not reveal clear trends in channel condition away from 

historic conditions (such as aggradation or enhanced incision rates), but this preliminary conclusion 

requires more analysis because the extensive inchannel bedrock limits the incision potential, and 

channel response is more likely manifested by more subtle changes in channel and bar morphology. The 

Tidal Reach is the only one for which available data indicates persistent channel incision and where 

cross-sections and previous reports indicate that sand and gravel extraction has exceeded sediment 

supply. Bed material supply in the Umpqua River system has likely been influenced by many

anthropogenic factors, including dams, placer mining, forest practices, and instream gravel mining, but 

the relative effects of each of these factors have not yet been determined. 

Outstanding Issues and Possible Approaches

Bed-Material Budget

A bed-material budget would provide critical information for understanding possible effects of 

instream gravel mining. Because the existing instream gravel mining operations are located along the 

South Umpqua River, a logical first step would be to develop a bed-material budget for those reaches 

most affected by instream mining: the Days Creek, Roseburg, and Garden Valley Reaches. An

expedient and relevant approach for developing this sediment budget could entail the following strategy: 

1. Employ a GIS-based approach to develop correlations between physiography, geology, and other 

established predictor variables and sediment production. Similar approaches have been applied to 

the Deschutes River (O’Connor and others, 2003), and the North Umpqua River (Stillwater 

Sciences, 2000), but here the GIS-based estimates could be calibrated against extensive sediment 

data collected by the USGS during 1950–70 and available (and possibly newly acquired) reservoir 

surveys. 

2. Apply a modified version of the morphological approach, which typically involves estimating 

sediment flux based on mapped changes in bar area between two time periods. Because gravel 

deposits along the Umpqua River system are difficult to discern accurately from aerial photographs, 

a modified approach, involving field mapping in conjunction with existing and ongoing operator 

surveys of erosion and deposition, would be required to obtain interpretable results. Although a 

morphologically based approach would be subject to large uncertainties, it could be used to judge 

the reasonableness of the GIS analysis and allow an independent assessment of possible temporal 
37

trends. Such data also could provide baseline information from which to design efficient monitoring 

strategies.

3. Analyze lithology (rock type) of gravel deposits to provide information on the relative contribution 

of bed-material from different source areas, as well as information on downstream clast 

disintegration.

4. Although direct measurements of bedload transport can be used to verify equations for bedload 

transport and to estimate actual bedload fluxes, such an approach is unlikely to provide useful 

information on a supply limited system such as the Umpqua River unless such measurements were 

conducted for several years over a large range of flow conditions. 

Legacy and Ongoing Effects of Placer Mining, Forest Practices, Impoundments and Instream

Gravel Mining

A key question, particularly for the South Umpqua River, is how past activities, such as late 19th

century placer mining, 20th century forest practices, instream gravel mining, and the Galesville 

Reservoir impoundment, have affected the present day gravel flux rates. Similarly, impoundments and 

forest practices may have had discernible effects on bed-material transport in the North Umpqua River. 

These questions are challenging because of the various time lags—perhaps up to centuries—involved in 

channel response, and the interactions of changed transport rates with various channel and floodplain 

areas that serve as storage and source areas for bed material. Although it may be difficult to quantify the 

exact effect of gravel extraction, placer mining or dam building on specific aspects of the gravel budget, 

examination of changes in channel morphology along potentially affected reaches may reveal trends 

attributable to certain activities. We anticipate that the most useful approach to deduce the relative 

importance of past activities is to employ a combination of:

1. Mapping the distribution of areas of active gravel transport and to analyze temporal trends in 

channel and floodplain morphology in light of known areas of land-use disturbance: To assess the 

possible effects of placer mining, such analyses would include the affected and downstream reaches 

of Cow Creek, Myrtle Creek, and Lookingglass Creek.

2. Resurveying cross-sections originally surveyed in the 1970s for a USGS flood study: By 

reoccupying cross-sections in reaches potentially affected by impoundments or placer mining, 

temporal trends attributable to these activities may be determined. 

Connections between Upstream Umpqua River and Tributaries and the Tidal Reach

Channel characteristics in the Tidal Reach are a function of upstream sediment supply as well as 

geologic conditions over the past 10,000 years. The sparse extent and volume of gravel bars (historically 

and presently) in the Coast Range Reach hints that bed-material fluxes have been small over the last few 

centuries, indicating that gravel from upstream is stored in the Garden Valley Reach or is disintegrating 

downstream. If either of these scenarios is valid, then much of the sediment in the Tidal Reach may 

reflect previous geologic conditions or inputs (for example, enhanced sediment production during the 

millennia after the Mazama eruption could have resulted in extensive aggradation in the Tidal Reach).

Alternatively, much of the sediment supplying the Tidal Reach may derive from tributaries directly 

entering the Tidal or lower Coast Range Reaches. Understanding the relative roles of current, historic, 

and prehistoric sediment dynamics is necessary to predict the response to the estuary to upstream 

perturbations. To address these issues, we would: 
38

1. Extend the GIS analyses, gravel lithology assessments, and morphologic budget approach to the 

Coast Range and Tidal Reaches so as to better understand sediment production and temporal 

changes in sediment flux for the entire Umpqua River study area. 

2. Resurvey the bathymetry of the Tidal Reach in order to better understand spatial and temporal 

patterns of sediment replenishment in formerly mined areas. Although past surveys are available for 

various sections of the Tidal Reach, a new survey could judiciously target areas that have not been 

mined for various time periods (for example, 2, 5, 10, and 20+ years), in order to determine how 

these sites have recovered following gravel extraction. 

3. Reoccupy cross-sections surveyed for a 1970s USGS flood study. To better understand how the 

Tidal Reach responds to sediment supply conditions in the upper reaches of the Umpqua River, a 

series of key cross-sections in the Coast Range and Garden Valley Reaches could be reoccupied and 

examined to determine decadal scale changes in channel condition. 

Balance between Sediment Supply and Transport Capacity

The long-term (decades to centuries) evolution of the Umpqua River will depend on the balance 

between sediment supply and transport capacity. Both factors likely have and will continue to be 

affected by dam building, flow regulation, and channel manipulation. An analysis of relative transport 

capacity could include: 

1. Assessment of gravel bar armoring ratios as described above. Although local site conditions exert 

strong influence on grain size characteristics, multiple measurements of surface and subsurface clast 

sizes may indicate longitudinal trends in relative transport capacity. Such observations may also 

support inferences of temporal changes in bed-material conditions drawn from other study 

components. 

2. Hydraulic modeling of selected reaches will enable estimation of transport capacity and its relation 

to sediment supply for a variety of future scenarios. One approach could be to develop a simple 1D 

(HEC-RAS) model for the Days Creek, Roseburg, and Garden Valley Reaches, allowing us to 

estimate sediment transport capacity for a range of flows. The longitudinal variation in transport 

capacity can then be compared against estimates of sediment supply and observed location of 

erosion and deposition as well as gravel-bar armoring ratios. The purpose of the model is not to 

directly estimate sediment transport using equations of bedload transport; as such an approach is not 

suited to the Umpqua River basin because these equations assume unlimited sediment supply, but 

rather to provide a basis for evaluating the balance between supply and potential transport for 

various flow and sediment supply scenarios. 
39

References Cited

Beckham, S.D., 1986, Land of the Umpqua, a history of Douglas County, Oregon: Roseburg, Oregon, 

Douglas County Commissioners, 285 p. 

Bunte, K., and Abt, S.R., 2001, Sampling surface and subsurface particle-size distributions in wadeable 

gravel- and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed 

monitoring: Fort Collins, Colorado, USDA Forest Service, Rocky Mountain Research Station,

General Technical Report RMRS-GTR-74, 428 p. 

CH2M-Hill, 1971, Umpqua River gravel study for Umpqua River navigation company: Corvallis, 

Oregon, 29 p. 

Curtiss, D.A., 1975, Sediment yields of streams in the Umpqua River Basin, Oregon: U.S. Geological 

Survey Open-File Report, 1 plate with text.

Dana, J.D., 1849, Geology, United States exploring expedition during the years 1828, 1839, 1840, 1841, 

1842, under the command of Charles Wilkes, U.S.N. [Volume X]: New York, Putnam, 756 p. 

Diller, J.S., 1914, Mineral resources of southwestern Oregon: U.S. Geological Survey Bulletin 546, 147 

p. 

Douglas, D., 1914, Journal kept by David Douglas during his travels in North America 1823–1827, 

together with a particular description of thirty-three species of American oaks and eighteen species of 

Pinus, with appendices containing a list of the plants introduced by Douglas and an account of his 

death in 1834: Published under the direction of the Royal Horticultural Society: London, William 

Wesley & Son, 349 p. 

Ham, D.G., and Church, M., 2000, Bed-material transport estimated from channel morphodynamics: 

Chilliwack River, British Columbia: Earth Surface Processes and Landforms, v. 25, p. 1123–1142. 

Harris, D.D., Hubbard, L.L., and Hubbard, L.E., 1979, Magnitude and frequency of floods in western 

Oregon: U.S. Geological Survey Open-File Report 79–553, 29 p. 

Jones, B.E., and Stearns, H.T., 1930, Water-power resources of the Umpqua River and its tributaries, 

Oregon: U.S. Geological Survey Water-Supply Paper 636–F, p. 221–330. 

Klingeman, P.C., 1973, Indications of streambed degradation in the Willamette Valley: Corvallis, 

Oregon: Water Resources Research Institute, WRRI–21, 99 p. 

Moser, S.A., 1976, Umpqua River navigability study: Salem, Oregon Division of State Lands, 131 p. 

O’Connor, J.E., Grant, G.E., and Haluska, T.L., 2003, Overview of geology, hydrology, 

geomorphology, and sediment budget of the Deschutes River basin, Oregon, in O’Connor, J.E., and 

Grant, G.E., eds., A peculiar river—Geology, geomorphology, and hydrology of the Deschutes River, 

Oregon: American Geophysical Union Water Science and Application Series No. 7, p. 7–29. 

Onions, C.A.,1969, Sediment transport in streams in the Umpqua River basin, Oregon: U.S. Geological 

Survey Open-File Report, 45 p. 

Oster, E.A., 1972, Flood profiles in the Umpqua River basin, Oregon, Part 1: U.S. Geological Survey 

Open-File Report, 119 p. 

Oster, E.A., 1973, Flood profiles in the Umpqua River basin, Oregon, Part 2: U.S. Geological Survey 

Open-File Report, 113 p. 

Oster, E.A., 1975, Flood profiles in the Umpqua River basin, Oregon, Part 3: U.S. Geological Survey 

Open-File Report, 108 p. 

Ramp, L., 1972, Geology and mineral resources of Douglas County, Oregon: Oregon Department of 

Geology and Mineral Industries Bulletin 75, 105 p. 

Scott, L.M., 1923, John Work’s journey from Fort Vancouver to Umpqua River, and return, in 1834: 

Oregon Historical Quarterly, v. 24, p. 238–268. 
40

Stillwater Sciences, 2000, North Umpqua cooperative watershed analysis, Technical appendix to the 

synthesis report, Appendix 2–1, Sediment budget for the North Umpqua River basin, Prepared for 

Pacificorp, North Umpqua hydroelectric project, FERC Project No. 1927: Portland, Oregon, 113 p. 

U.S. House of Representatives, 1871, On navigation of Umpqua River: House Miscellaneous 

Document, 41st Congress, 3rd session, No. 21. 

U.S. House of Representatives, 1911, Examination of Umpqua River, Oregon: House Miscellaneous 

Document, 62nd Congress, 2nd session, No. 276. 

Winterbotham, J., 1994, Umpqua—The lost county of Oregon: privately published, 156 p. [Available at 

http://truefresco.org/bookshop/4_14279241_B0006P7PLQ_Umpqua-The-lost-county-of-Oregon.html, 

accessed March 10, 2009] 

Winterbothom, J., 2000, Footsteps on the Umpqua: Lebanon, Oregon, Dalton Press, 252 p. 

Wolman, M.G., 1954, A method for sampling coarse river-bed material: American Geophysical Union 

Transactions, v. 35, p. 951–956.