COLUMBIA RIVER BASIN PROJECT
FOR WATER SUPPLY AND WATER QUALITY MANAGEMENT
SEDIMENT PRODUCTION RATING
UMPQUA BASIN
OREGON
Prepared by: W. E. Bullard
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Region IX
Division of Water Supply and Pollution Control
Room 570 Pittock Block
Portland 5, Oregon
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This working paper contains preliminary data and information primarily
intended for internal use by the Columbia River Basin staff and
cooperating agencies. The material presented in this paper has not
been fully evaluated and should not be considered as final;
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SEDIMENT PRODUCTION BATING
UMPQUA BASIN
OREGON
INTRODUCTION
The sediment production rating is an attempt to assess a major impact of
land condition, use, and management in a watershed on the quality of water
produced by that watershed. The rating for the Umpqua Basin was done as
a part of the Columbia Water Resources Project. The first work of the
kind was done on the Umpqua Basin for five reasons: - information on the
area was desired to supplement a report due the Corps of Engineers within
the year; Douglas County (practically synonymous with the Umpqua Basin
as to area) had collected four and a half years of bi-weekly suspended
sediment sampling data for ten stations on the Umpqua River and its
tributaries; the Forest Service pilot forest soils survey in the South
Umpqua River Watershed provided detailed soils information for part of
the mountain area; the hoped-for information on rate of sediment produc-
tion might prove useful in connection with the studies on the Umpqua
River estuary; and the known range of erosion/sedimentation conditions
was believed to represent the extremes to be found in and west of the
Cascade Range.
SUMMARY AND CONCLUSIONS
i
Over all, the Umpqua Basin is rated "moderate" in sediment production.
Broadly interpreted, the sediment production ratings used correspond to
average sediment loads in streamflow as follows:
Rating Average Sediment Load
Class in ppm
Slight under 50
Low 50 to 150
Moderate 150 to 500
High 500 to 1,500
Very High 1,500 plus
Thus the "moderate" rating indicates for the 6,700,000 acre-feet (1) aver-
age annual water yield of the Basin an average sediment movement between
1,000 and 3,000 acre-feet; or in other terms, from 350 to 1,100 tons per
square mile of contributing watershed.
Highest rates of sediment production are found in the southern part of
the basin, in the upper South Umpqua River and Cow Creek Watersheds. Both
the Days Creek and the upper Cow Creek Watersheds were rated 'Very High."
Low rates are found on the western side of the main Umpqua River and in
the North Umpqua River Watershed, with the lowest in the pumice-blanketed
upper North Umpqua River Watershed above the dams of the California-
Oregon Power Company. .
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From the standpoint of natural instability, the "red hill" clayey soil
areas of the central part of the basin provide the greatest erosion/sedi-
mentation potential. These soils are typical of much of the Lookingglass,
Calapooya, and Elk Creek drainages.
Considering the effects of land use, the deeply weathered granodiorites
of the Cow Creek Watershed and the green tuffs and breccias of the South
Umpqua River Watershed produce the most sediments.
DESCRIPTION OF THE BASIN
The Uaipqua Basin is irregularly triangular in shape, 115 miles long from
the crest of the Cascade Range west to the Pacific Ocean, and 75 miles
wide north to south across the center. Basin area is approximately 4,560
square miles (1). Elevations range from sea-level to above 9,000 feet
atop Mt. Thielsen at the head of the North Umpqua River. Topography in
the mountain areas both in the Cascades and in the Coast Range is rough
with narrow, steep-walled valleys except in the central part of the basin
where rolling hills dominate the landscape.
Drainage is westerly from the Cascade Range to the Pacific Ocean. The
North Umpqua and South Umpqua Rivers meet in the center of the basin to
form the Umpqua which winds north and then west through the Coast Range
to Winchester Bay. Smith River in the northernmost part of the basin is
tributary to the Umpqua at the head of the Bay. Mill Creek from the Coast
Range on the south, and Elk Creek and Calapooya Creek from the Cascade
foothills on the east are major tributaries of the main Umpqua River.
Olallie Creek, Cow Creek, Elk Creek, and Jackson Creek are major tributaries
of the South Umpqua on the southern edge of the basin. Little River, Rock
Creek, Steamboat Creek, Fish Creek, Clearwater River, and Lake Creek are
the principal tributaries of the North Umpqua River in the Cascades on
the eastern side of the basin.
Stream gradients vary widely. The upper half of the North Umpqua has
a gradient of 83 feet per mile; the lower half, 19 feet per mile. Cow
Creek has a gradient of 23 feet per mile. The upper South Umpqua has a
gradient of 42 feet per mile; the central part, 13 feet per mile; and the
lower (below Cow Creek), 6 feet per mile. The main Umpqua has a gradient
of about 4 feet per mile.
Geology is mixed. Most of the Coast Range area in the lower main Umpqua
and Smith River Watersheds is underlain by interbedded shales and hard
sandstones and conglomerates of the Eocene Tyee formation. The soils are
for the most part sandy clay loams (2). Altered lava, tuff, breccias and
shales of the Jurassic Rogue River and associated formations underlie the
central and foothill areas of the basin. The unstable "red hill" clay
soil is typical of much of this central portion. Eocene volcanic rocks
underlie most of the Cascade Mountain section of the basin. Soils on these
rocks have a fairly high erosion potential. The recent volcanic rocks and
pumice of the uppermost eastern part of the basin support somewhat more
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stable soils, though pumice can erode readily if disturbed. The southern
part of the basin in the Klamath-Siskiyou geologic province is underlain
by granites, metamorphosed sediments, and serpentines. Soils are variable
on these rocks, but all are unstable and have a very high erosion potential.
Climate is mild, though varying with elevation. Summers are warm and
fairly dry. Winters are cool and wet, with most precipitation as rain
except in the higher easternmost part of the basin. Recorded temperatures
range from 6°F to 109°F. Average length of growing season in the valleys
is 190 days. The varied topography and high relief strongly influences
the precipitation pattern. In the western coastal mountain part of the
basin average annual rainfall ranges from 70 to 100 inches. The central
valley has 25 to 30 inches, the foothills 30 to 50 inches, and the eastern
Cascade Mountains from 50 to 70 inches average annual precipitation.
Rainfall intensities of four inches in one day have been recorded at
Roseburg in the driest part of the basin; much higher amounts may be
expected in the mountainous areas.
Streamflow is high in winter from rainfall and in spring from snowmelt,
low in the dry summer season. Mean annual runoff for the Umpqua River at
Elkton, about 80 per cent of the entire basin contributing, is 5,378,000
acre-feet; this is equivalent to a mean flow of 7,400 cubic feet per
second. Extremes of flow at the same point have varied from 640 to 218,000
c.f.s.; from less than 10 per cent to nearly 3,000 per cent of the mean.
Some of the tributaries are even more variable; - the upper South Umpqua
with a mean flow of 917 c.f.s. has had a minimum of 20 c.f.s. and a
maximum of 29,900 c.f.s., from 2 per cent to 3,200 per cent of the mean.
The Umpqua Basin is 88 per cent forested (1). At the higher elevations
are subalpine forests of lodgepole pine, true firs, spruce, and mountain
hemlock. At middle elevations are mixed conifer forests of ponderosa pine,
Douglas-fir, sugar pine, and incense cedar. Around the valley in the
drier areas the forest is predominantly open ponderosa pine or madrone
and oak and brush. Rolling hills in the valley are in grassland, and the
bottom lands are cultivated. Coast range parts of the basin are covered
with a dense Douglas-fir, western hemlock, and western redcedar forest.
Most of the 2,876,000 (1) acres of forest land have commercial potential.
The 487,000 acres of agricultural land are three-fourths pasture land
and one-fourth cropland.
Forest land is about sixty per cent in public ownership. Public lands are
used primarily for timber harvest, but also for recreation. Private forest
lands are also used for grazing by domestic stock. Sheep graze most of
the hill pastures. Crops include corn, hay, small grains, and garden
truck. The county seat, Roseburg, has a population of about 12,000; and
Douglas County as a whole about 68,000. Industry is largely forest-based,
Douglas County being one of the leaders in timber and lumber production.
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According to the Census (3), some 32 per cent of Douglas County is agricul-
tural land. Much of this is forested land used for pasture, since forest
statistics show 83 (1) per cent of the County as commercial forest land.
The cultivation of soil for pasture and crops, the harvest of timber, and
the construction of roads are the major soil-disturbing land uses contrib-
uting to sediment production.
RELATED STUDIES BY OTHER AGENCIES
In a report (4) on the October 1950 floods, the Forest Service noted that
the South Umpqua River carried a suspended sediment load of 6,850 ppm a
day after the flood crest with streamflow at less than half the peak. The
suspended sediment sampling done at several stations in the Umpqua Basin by
the same agency (5) (6) through the 1950-52 seasons showed ranges of 0.2
to 10 ppm at low flow to ranges of 45 to 1600 ppm at high flow. Following
the extreme flows of October 1950 the maximum values recorded for Umpqua
Basin stations were from 300 to 6,850 ppm.
Anderson (7), reporting on sedimentation in the neighboring Willamette and
Rogue River Basins, noted that logging and road development without preven-
tive measures could increase sediment discharge by three times, most of
the increase associated with extension of the access road system. He
estimated the amount of sediment produced by eroding banks along main
channels at five tons per year per running foot of eroding bank. In the
upper Willamette Basin he estimated that bank erosion contributed 54 per
cent of the total sediment discharge, forest land 24 per cent, and agricul-
tural land 22 per cent.
Hayes and Herring (2) calculated from Forest Service data (6) showing the
average sediment load in the South Umpqua River at 552 ppm that less than
40 per cent of the drainage basin yielded 1-3/4 million tons of sediment
annually. They noted from their observations that 90 per cent of the
sediment may come from 10 to 20 per cent of the watershed. They reported
that the more important critical sediment source areas were roads, skid-
trails, log landings, and streambanks scarred by logging.
Barton (5) reported the following summary of two years of sediment sampling
in the Umpqua Basin:
Stream
South Umpqua (Tiller)
South Umpqua (Brockway)
North Umpqua (Glide)
Elk Creek (Tiller)
Little River (Glide)
Calapooya (Nonpareil)
Suspended Sediment Load, ppm
Maximum
850
6,850
2,100
450
777
2,930
Minimum
Trace
Trace
3
Trace
2
Trace
Average
I/
94
552
220
106
104
252
21
49
102
94
56
61
jy 15 samples including October 1950 peak flow
2_/ 14 samples excluding October 1950 peak flow
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He noted a tendency for the streams to have very high sediment loads during
the months October through December, due both to high flows with flushing
out of sediments dropped by receding flows of spring and summer and to
caving of streambanks.
Since February 1957 the Douglas County Water Resources Board has been
taking suspended sediment samples bi-weekly at ten stations in the Umpqua
Basin. To date about 120 samples have been collected for each station,
but unfortunately none have been taken at times of peak flow at most
stations. Loads observed have ranged from 0 to 903 ppm.
Flaxman (unpublished office report) analyzed the Douglas County sampling
data and ranked the different tributary watersheds according to yield. He
noted the lack of sufficient peak flow data to round out the record. He
also related the sediment loads to geology and soils, pointing out that the
Jurassic Rogue River formation (altered lava, tuffs, and interbedded sand-
stones and shales) had the highest sediment production potential, and the
Eocene Tyee (hard sandstones) the lowest. Eocene volcanic formations were
rated intermediate.
The Forest Service pilot soil survey on the upper South Umpqua River Water-
shed furnished detailed information on soils and their erosion potential
rated in terms of erosion hazard, slide hazard, and slump hazard. Seven
soils were in the high hazard category: These are in the Deadman, Coyote,
Vena, Straight, Prong, Hummingbird, and Whitehorse series. The Deadman
and Straight are derived from greenish breccias and conglomerates; the
Vena from acid igneous rocks; the Prong from andesites and diorites; and
the Coyote, Hummingbird, and Whitehorse from basalts. Area covered by the
survey included the entire upper South Umpqua Watershed north of Jackson
Creek and east of Deadman Creek, in the Umpqua National Forest.
SURVEY METHODS
Surveying was done on a sampling basis by visiting as many areas as had
convenient automobile access. Conditions in road ditches, road cuts and
fills, stream channels, pastures, range lands, logged areas, and slide
areas were observed, and the local areas given a sediment production rating
of slight, low, moderate, high, or very high. Work began in the upper Cow
Creek Watershed, an area known to have a very high erosion potential
because of its geology - a deeply weathered granodiorite that, when
stripped of its cover, melts like sugar. This area set the standard for
the "very high" rating. 'Channel sediment deposits and the high turbidity
of Cow Creek after a rain supported the rating estimate. Aerial photo
mosaics were used to guide delineation of areas of similar ratings. Geo-
logic maps were also used as a guide. The field "eyeball" ratings were
finally checked against the sediment sampling data available.
The sediment production rating thus is largely subjective. It is based on
field observation and interpretation of geology and soils, topography,
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vegetation cover conditions, and the superposed land use in the area under
study. It involves consideration also of climatic and streamflow records,
sediment sampling data, and sediment deposition data.
SURVEY FINDINGS
Observed conditions varied greatly. In some cases the streams themselves
seemed to provide most of their sediment load by active bankcutting. In
others, eroding range and logged lands appeared to be the principal sedi-
ment contributors. In still others, slides and slumps were prime sediment
sources. Everywhere, roads vere a major source, though road contributions
were far the greatest in the "red hill" soils areas and on the deeply
weathered granodiorites.
In some areas land use appeared to be the controlling factor; in others
geology and soils seemed most significant. Climate may play a part: - the
western two-thirds of the basin is subject to rains of fairly high inten-
sity, while the eastern third in the higher elevations of the Cascades
receives much of its precipitation as snow. About 10 per cent of the water-
shed in the extreme easternmost part, the North Umpqua drainage above
Toketee Falls, is covered with a highly permeable pumice soil. This area
has the lowest sediment production rating of any.
Topography of the middle and upper elevations of the Umpqua Basin is rough.
Slips and slides are common, particularly where timber access and other
service roads traverse steep side slopes. Areas of rough topography
usually show a higher rate of soil loss; however, the horizontally bedded
sandstones of the western part of the basin even on the steeper slopes are
erosion-resistant. On the other hand, the clayey "red hill" soils devel-
oped on the altered tuffs and breccias are highly erodible because of their
tendency to slump even on the rolling topography at lower elevations.
Geology has effects both in terms of rock structure and of sediment parti-
cle size. In Cow Creek, tributary to the South Umpqua River, much of the
erosion takes place on deeply weathered coarse-grained granodiorites, and
the sediment is predominantly in the sand grades. Not too much of the sand
fraction is caught in sampling suspended load, as the coarser sand moves
by saltation along the channel bottom. Channel deposition indicated plenty
of sand movement in Cow Creek, by field observation rated the greatest
sediment producer of the basin. On the basis of the suspended sediment
sampling records, however, Cow Creek holds only an intermediate ranking.
Land use (and abuse) is the controlling factor imposed on the landscape.
Heavy and long-continued livestock grazing has in many foothill areas
thinned and weakened the plant cover and compacted the surface soil; erosion
and consequently sedimentation have been increased. Roads and canals,
powerlines and pipelines have greatly disturbed the soil and the natural
drainage pattern throughout the basin. Urban and suburban and recreation
area developments locally have not only disturbed the soil but have covered
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it with impermeable roots and pavement. Agriculture has changed the plant
cover almost completely in the valley bottoms, in addition to disturbing
the soil by cultivation. Logging-has removed some of the plant cover
temporarily, has disturbed the soil to some extent in some areas, and has
affected runoff and drainage patterns.
Ratings given the various parts of the Umpqua Basin are as follows:
Rating Area (by drainages)
Slight
Low
Moderate
High
Very high
North Umpqua above Boulder Creek
North Umpqua above Glide, to Boulder Creek
South Umpqua below Winston
Main Umpqua (except Calapooya Creek and
Elk Creek)
Deer Creek near Roseburg
Little River, lower half
Elk Creek, central part near Drain
Little River above Peel
South Umpqua above Deadman Creek
South Umpqua, from Cow Creek to Looking-
glass Creek
Diallie Creek above Berry Creek
Myrtle Creek below Frozen Creek
Elk Creek below Drain
Smith River below Sisters Creek
Calapooya Creek below Gassy Creek
Oldham Creek below Bachelor Creek
Yoncalla Creek above Yoncalla
Smith River above Sisters Creek
Pass Creek above Fitch Creek
Elk Creek above Samson Creek
Oldham Creek above Bachelor Creek
Calapooya above Gassy Creek
Lookingglass and Olallie Creek
Cow Creek below Glendale
Myrtle Creek above Frozen Creek
South Umpqua above Cow Creek to
Deadman Creek
Boze Creek, Prong Creek, and Rock Creek
at head of South Umpqua
Cow Creek above Glendale
Days Creek
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Any tributaries not mentioned are rated with the parts of major streams
where the tributaries join.
By proportion, of the basin area and by weights.,, the ratings are as
follows:
Equivalent Relative Sediment
Rating Weight Per Unit Area Area, 7. Contribution, 7,
Slight 1 91
Low 3 33 7
Moderate 9 27 18
High 27 27 52
Very High 81 4 22
100 100
Special problem areas could include any of those given a "high" or'Very
high" rating, or 30 per cent of the entire basin. Yet some problem areas
are of little significance except in reservoir sedimentation because the
sediments produced are trapped behind dams and do not affect long reaches
of stream. Reasons for existence of the problems vary. Days Creek
suffers severe bankcutting along much of its length. Calapooya Creek
suffers severe bankcutting plus logging damage on its watershed. Cow
Creek has suffered from careless treatment of the delicately balanced
unstable granodiorite-based soils in the upper watershed, from considerable
soil disturbance by road-building and logging and from some bankcutting
in the lower watershed. The upper Smith River Watershed suffers from
excessive soil disturbance by road-building and logging on very rough
topography, and a large amount of logging debris has been left in the chan-
nels of many of the tributaries.
DISCUSSION
Though the ratings were guided to some extent by the suspended sediment
sampling data, there is no good correlation between them. The sediment
data were recognized as incomplete, both as to size of sediment particle
and size of flow sampled. For example, Steamboat Creek (a North Umpqua
River tributary in the high mountains with fairly good watershed conditions)
showed by the sediment sampling about one-fourth the average sediment load
sampled in Calapooya Creek (a foothill tributary with a badly abused
watershed and plenty of channel indications of considerable sediment move-
ment) . These watersheds are of comparable size; the field rating put the
sediment contribution from Steamboat Creek at only one-twentieth of that
from Calapooya Creek. Steamboat Creek had been sampled a couple of times
at very high flow stages, while Calapooya Creek had not been sampled at
much above mean flow.
Analysis of the sampling shows that the low frequency high flows carry a
disproportionate - and the major - share of the sediment load. About seven
per cent of the flows sampled carried .28 per cent of the average sediment
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concentrations observed; combining flow times sediment concentration, this
seven per cent of high flows then carried about 90 per cent of the total
sediment load.
Some high sediment concentrations were noted at times of average to low
flow; these were due to mining, roadbuilding, and gravel-washing operations.
Mechanically-patterned sampling on a bi-weekly schedule though providing
120 samples per station in four years and a half did not cover the range
of streamflow occurrences needed for a complete picture. Low flow condi-
tions are plentifully represented, but the significant high flow conditions
are not represented at all at some stations. Either a total of fifteen
to twenty years of sampling, or special attempts to sample at times of high
flow will be needed. Cooperation with the Douglas County Water Resources
Survey has been established to get high flow samples this coming wet season.
RECOMMENDATIONS FOR IMPROVEMENT (2), (8), (9), (10)
Where soil and channel conditions are naturally unstable, avoidance of
undue disturbance will prevent large increases in erosion and sediment
production. In the granodiorite areas, it is possible to build roads and
harvest the timber without abusing the land; disposal of road drainage at
frequent intervals, dispersal of drainage in contour infiltration trenches,
high-lead cable logging instead of tractor logging, restricted use of
skidtrails to prevent deep gouging, installation of waterbars for drain-
age diversion in abandoned skidtrails and spur roads, mulching and seeding
cut and fill slopes, and immediate replanting of cutover areas all will
help keep erosion and sediment production at a low level. In the "red
hill" soil areas where there is a persistent tendency for the land to
slump and slide, the less road-building disturbance the better. Where
roads are necessary, the penalty of increased erosion and sedimentation
must be accepted.
Road maintenance is a common source of stream turbidity and sediment in
the Umpqua Basin. Overcasting of excess material from ditches and road
surfaces directly into stream channels appears to be a regular practice.
This practice should be stopped; the excess material should be end-hauled
to a location where it will not directly damage the streams and where it
can be stabilized. The same recommendation applies to road construction.
In laying out timber harvest operations, the road system should be planned
for the minimum necessary. Cutting areas should not be laid out across
streams, and where there is little danger of windthrow cutting boundaries
should leave a protective strip of trees along streams to provide shade
and to trap debris from slopes above. Uphill cable logging should be
planned wherever possible. Logs should be swung across channels, not
dragged across. Landings should be located away from channels; both land-
ings and skidtrails should be drained to places where water can infiltrate
safely into the soil. Repeated use of the same skidtrails should be
limited, and tractor yarding stopped when the soil is wet. Timber should
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be felled upslope away from channels, and logging slash kept out of chan-
nels. Channel crossings should be on temporary culverts to be carefully
removed when the work is finished. Digging gravel for road surfaces from
live streams should not be permitted.
Quarry and mine drainage should be diverted to infiltrate into the soil
away from streams. Waste piles should be located so that they will not
erode into streams.
Channel banks subject to cutting should be protected with riprap and
planted to willows and alder. Channel cutoffs and diversions should be
avoided wherever possible; encroachment of road fills on channels should
also be avoided.
Burned areas should be seeded with quick-growing cover crops and planted
to trees to prevent excessive erosion, loss of productive capacity, and
sedimentation.
Unstable debris accumulations in channels should be cleaned out.
Erosion "sore spots" that persist and do not heal should be treated. Drain-
age diversion, contour furrowing, staking and mulching, seeding and planting
are useful methods.
Grazing on hill lands should not be permitted to the point that cover den-
sity is reduced below 70 per cent.
Cultivation of sloping land should be on contour, in strips with bands left
in full coyer between to trap runoff and sediment. Irrigation should be
done in such a way that waste waters do not cause erosion.
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BIBLIOGRAPHY
(1) "Umpqua River Basin", State Water Resources Board, July 1958
(2) "Some Water Problems and Hydrologic Characteristics of the Umpqua
Basin", G. L. Hayes and H. G. Herring, July 1960, PNW Forest and
Range Experiment Station
(3) Census of Agriculture 1960
(4) "Floods of October 1950 in Southern Oregon", Office Report, PNW
Forest and Range Experiment Station, 1951
(5) "Progress Report on Suspended Sediment Sampling in Several Western
Oregon and Western Washington Streams", by Manes Barton, Research
Note No. 75, PNW Forest and Range Experiment Station, 1951
(6) USDA Flood Control Survey Stream Sediment Sampling Record, Mimeo-
graphed Monthly November 1950 to July 1952, PNW Forest and Range
Experiment Station
(7) "Suspended Sediment Discharge as Related to Streamflow, Topography,
Soil and Land Use", H. W. Anderson, Transactions AGU Vol. 35 No. 2,
April 1954
(8) "Some References on Watershed Management", by W. E. Bullard,
Research Note No. 63, PNW Forest and Range Experiment Station, 1950
(9) "Watershed Protection - A Manual for Forest Landowners", Water
Management Committee, Columbia River Section, Society of American
Foresters, 1961
(10) Forest Service Handbook, Title 2500 - Watershed Management, and
2533 - Land Treatment Measures, 1959
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