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TECHNICAL REPORT NO .2
prepared
THE
OLD WEST REGIONAL
by
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by
Roy Koch, Hydrologist
Montana Department of Natural Resources and Conservation
Helena, MT
Robert Curry
Mark Weber
Geology·Department
University of Montana
Missoula, MT
TECHNICAL REPORT NO.2
conducted by the
Water Resources Division
Montana Department of Natural Resources and Conservation
32 S. Ewing
Helena, MT 59601
Bob Anderson, Project Administrator
Dave Lambert, Editor
For the
Old West Regional Commission
228 Hedden Empire Building
Billings, MT 59101
Kenneth A. Blackburn, Project Coordinator
July 1977
1730 K Street, N. W.
Suite 426
The Old West Regional Commission is a Federal-State
partnership designed to solve regional economic
problems and ·stimulate orderly economic growth in
the states .of Montana, Nebraska, North Dakota,
South· Dakota and Wyoming. Established in 1972
under the Public Works and Economic Development
Act of 1965, it is one of seven identical commissions
throughout the country engaged in formulating and
carrying out coordinated action plans for regional
economic development.
COMMISSION MEMBERS
State Cochairman
Gov. Thomas L. Judge of Montana
Alternate: Dean Hart
Federal Cochairman
George D. ~cCarthy
··State· Members·
Gov. Edgar J. Herschler o.f Wyoming
Alternate: Steve F. Freudenthal
Gov~ J. James Exon of Nebraska
Alternate: Jon H. Oberg
Gov. Arthur A. Link of North Dakota
Alternate: Woody Gagnon
Gov. Richard F. Kneip of South Dakota.
Alternate: Theodore R. Muenster
COt1MISSION OFFICES
201 Main Street
Suite D
Washington, D. C. 20006
202/967-~491
Rapid City, South Dakota 57701
605/348-6310
Suite 228
Heddon-Empire Building
Billings, Montana 59101
406/657-6665
ii
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FOREWORD
The Old West Regional Commission wishes to express its appreciation for
this report to the Montana Department of Natural Resources and Conservation,
and more specifically to those Department staff members who participated
directly in the project and in preparation of various reports, to Dr. Kenneth A.
Blackburn of the Commission staff who coordinated the project, and to the
subcontractors who also participated. The Yellowstone Impact Study was one
of the first major projects funded by the Commission that was directed at
investigating the potential environmental impacts relating to energy develop-
ment. The Commission is pleased to have been a part of this important research.
George D. McCarthy
Federal Cochairman
FIGURES.
TABLES . .
ABBREVIATIONS USED IN THIS REPORT • • ' • II •
PREFACE ..... .
The River ..
The Conflict.
The Study ...
Acknowledgments
PART I. CHANNEL FORM AND PROCESSES.
INTRODUCTION ......... .
GEOLOGIC HISTORY AND STRATIGRAPHY
GEOMORPHOLOGY OF THE YELLOWSTONE RIVER
CHANNEL AND TRIBUTARIES. . _
Channel Form . . . . . . . . . . .
Yellowstone Mainstem .... .
Tributaries ........ .
Comparison With Other Rivers.
Channel Processes.
HYDROLOGY . . . . . . . . . . . . .
Climate. . . . . . . . . . .
Streamflow Characteristics ..
Effects of Existing Water Development and Use ..
Hydraulic Geometry ........... .
At-a-Station Hydraulic Geometry .. .
Constant-Frequency Hydraulic Geometry .
Dimensionless Hydraulic Geometry.
BED MATERIAL AND SEDIMENT TRANSPORT
Bed Material ..... .
Sediment Transport . . .
Suspended Sediment.
Bedload ..... .
IMPACTS OF WATER WITHDRAWALS.
Projections of Future Use. . .
Impact of Water Development on Ch~nnel
Form and Processes ....
Impacts c· Onstream Storage . .
Impacts of Diversion ..
iv
. .
. .
. .
vi
viii
X
1
1
1
5
6
7
9
11
19
19
19
32
38 . . . 38
. . 43
43
43
50 . . . 50 . . . 52
52
61
65
65
65
68
73
83
83
83
83
84
SUMMARY AND CONCLUSIONS . . . . . . . . . . . . . . . . .
PART II. VIGIL NETWORK ESTABLISHMENT IN SOUTHEASTERN "MONTANA.
INTRODUCTION.
Purpose.
Scope ..
Study Area
METHODS ....
Basic Concepts
Stream Regimen
EXISTING SITUATION
Vigil Site Documentation .
Data Synthesis ....
Applicability of Data.
SUMMARY
APPENDIXES .
A. Projections of Future Use ........ .
B. Bighorn River Morphology Prior to and after
Yellowtail Dam ............... .
C. Sample Contents of Vigil Network Site Folder.
LITERATURE CITED . . . . . . . . . . . . . . . . . . .
v
. . ..
89
91
93
93
93
93
99
99
100
103
103
103
104
113
115
117
125
139
159
1. Yellowstone River Basin ..
2. Generalized geology of the Yellowstone River Basin .
3. Profile of the Yellowstone River Mainstem between
Billings and Sidney ............. .
4. Five representative reaches of the Yellowstone River
5. Characteristic forms of the Yellowstone River Channel.
6. Reach 1: the Yellowstone River from Huntley to Pompey's
Pillar .
7. Reach 2: the Yellowstone River from the Mouth of the Bighorn
3
13
20
21
24
25
River to the Mouth of Froze-to-Death Creek . . . . . . . . . 27
8. Reach 3: the Yellowstone River from near Hathaway to above
Miles City . . . . . . . . . . . . . . . . . . . . 29
9. Reach 4: the Yellowstone River from above the Mouth of the
Powder River to below Terry. . . . . . . . . . . . . . . . . 30
10. Reach 5:
to Savage
the Yellowstone Riv~~ from Intake Diversion Dam
11. Bighorn River sections delineated for interpretation of aerial
31
photographs. . . . . . . . . . . . . . . . . . . . . . . . 33
12. Relationship of rivers in the Yellowstone Basin to the general
relation for channel form presented by Leopold and
Wolman (1957). . . . . . . . . . . . . . . . . . . 39
13. Average annual precipitation in the Yellowstone River Basin. 45
14. Mean monthly flows of the Yellowstone River mainstem at
three stations . . . . . . . . . . . . . . . . . . . 49
15. Gaging stations in the Yellowstone River Basin, Montana. . 55
16. At-a-station hydraulic geometry for the Tongue River at
Miles City . . . . . . . . . . . . . . . . . . .
17. Lower Yellowstone River Basin constant-frequency
hydraulic geometry: w8 and Ds ........ · · · · · ·
18. Lower Yellowstone River Basin constant-frequency hydraulic
geometry: As and v8 . . . . . . . . . . . . . . · . . · .
vi
57
59
60
19. Dimensionless rating curve of the Yellowstone mainstem.
20. Dimensionless rating curve of the Bighorn River
21. Dimensionless rating curve of the Tongue River
22. Dimensionless rating curve of the Powder River . . .
23. Grain size distribution from surface pebble counts on the
lower Yellowstone River . .
24. Bed materia 1 bulk samples . . . . . . . .
25. Typical bed materia 1 for the Yellowst6ne River
above Sidney. . . . ... . . . :. . ' . . . . . .
26. Suspended sediment load vs. discharge: Yellowstone River
near Sidney . . . . . . . . . . . . . . . ..
I
27. Suspended sediment load vs. discharge: Powder River near
Locate . . . . . . . . . . . . . . . . . .
28. Suspended sand load vs. discharg~: ·Yellowstone_River.
near Sidney . .· . . . . . . . . . _ . . . . . . . u
29. Streamflow and suspended sediment discharges for the
Bighorn River at Bighorn ...•..........
30. Suspended sediment rating curves for the Bighorn River
at Bighorn: 1950, 1958, and 1970 ......... .
31. Estimated relationship between discharge and particle
size moved for the Yellowstone -River at Miles City ..
62
62
63
. 63
66
67
68
.. . . . . 70
. . . . 71
72
74
75
78
-32. Schoklitsch bedload curve: Yellowstone River at Miles City 80
33. Sediment duration curve showing most effective discharge:
·Yellowstone River at Miles City ............ .
34. Sediment duratiori curve showing most effective discharge:
Yellowstone River at Sidney ............. .
35. Vigil network stations in southeastern Montana and the
approximate boundaries of the watersheds monitored ..
36. Generalized bedrock geology of southeastern Montana
37. USGS streamflow gaging stations used in this study
38. 1.5-year discharge as a function of drainage area .
vii
. ' . . . .
81
82
95
97
105
111
1.
2.
3.
Assumed chronology of erosion surfaces in the northern
Great Plains ................... .
Geomorphic characteristics of the middle and lower
Yellowstone River Basin and major tributaries ...
Changes in the Bighorn River channel after construction
of Yellowtail Dam ................•..
4. Number, average area, and total area of vegetated
islands, island gravel bars, and lateral gravel bars
on the Bighorn River before and after construction
15
. . . . . . . 26
34
of Yellowtail Dam . . . . . . . . . . . . . . . . . ..... · · 35
5. Loss in Bighorn River area following construction of
Ye 11 owta i 1 Dam. . . . . . . . . . . . . . . . . . . .
6. Bed material of the Tongue and Powder rivers, Montana
7. Streamflow characteristics in the Yellowstone River Basin .
8. Data from flow duration curves for the lower Yellowstone
River Basin . . . . . . . • . . ...
9. Flood frequencies for the lower Yellowstone River Basin .
10. Monthly distribution of irrigation water withdrawals and
36
37
44
47
48
return flow . . . . . • . • . . . . . • . . . . . . . . . . . . . 50
11. Coefficients and exponents for ·at-a-station hydraulic
geometry, Yellowstone River Basin .............•.... 53
12. Comparison of at-a-station hydraulic geometry exponents
-for the Yellowstone Basin with other published values
13. Sediment size classification ....... .
14. Suspended sediment data for the Yellowstone River Basin
15. Maximum flows for the Lower Yellowstone River Basin in 1976
16. Bedload data collected in 1976: Yellowstone River Basin
58
65
69
76
at Sidney ..... · ..... . . . . . . . 76
17. Projected percentages of streamflow depletions in the
Yellowstone River ............... . . . . . . 85
18. Changes in width, depth, and velocity at bankfull discharge
(Q 1· 5) due to decreased flows projected for two Yellowstone
River Stations at the high development level ............. 86
viii
j:
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I
1
I
19. Projected losses in bed material transport capacity for two
stations on the Yellowstone River .... ~ . . . . . . . . . . . . . 86
20. Bankfull discharge {Q 1 5 ) for selected USGS gaging stations
in the Yellowstone Riv~r Basin ......... .
21. Little Bighorn River drainage basin components .
22.
23.
Greatest two-year, 24-hour precipitation events ..
Greatest two-year, one-hour precipitation events
ix
107
108
109
110
acre-feet af
af/y
b/d
cfs
cfs/rn.2
acre-feet per year
barrels per day ·
cubic feet ner second
cubic feet per second per square mile
em centirn.eters
nNRC Department of Natural Resources and Conservation
EIS Environrn.ental Imoact Statement
ft feet
ha hectares
hm3 cubic hectometers
hm3Jy cubic hectometers per year
in inches
km kilometers
km2 square kilometers
m meters
m3Jsec cubic meters per second
m3Jsec/krn.2 cubic meters per second per square kilometer
''1EAC 1·1ontana Enerqy J\dvi sor_v Council
mi miles
mm millimeters
~af/y million acre-feet oer year
mmt/y mi 11 ion tons per year
mw meqawatts
0 discharqe
nQ·R1.5 hiqh flow occurrinq, on the average, every 1.5 years
bankfull.discharqe
RM river mile
RKM river kilometer
t/d tons per day
t/yr tons per year
t/mi2Jyr tons oer square mile per year
USDI United States Department of Interior
USGS United States Geoloqical Survey
yr year
-X
THE RIVER
The Yellowstone River Basin of southeastern Montana, northern Wyoming,
and western North Dakota encompasses approximately 180,000 km2 (71 ,000 square
miles), 92,200 (35,600) of them in Montana. Montana's portion of the basin
comprises 24 percent of the state's land; where the river crosses the
border into ~orth Dakota, it carries about 8.8 million acre-feet of water per
year, 21 percent of the state's average annual outflow. The mainstem of the
Yellowstone rises in northwestern l·lyoming and flows generally northeast to its
confluence with the Missouri River just east of the Montana-North Dakota
border; the river flows through Montana for about 550 of its 680 miles. The
major tributaries, the Boulder, Stillwater, Clarks Fork~ Bighorn, Tongue, and
Powder rivers, all flow in a northerly direction as shown in figure 1. The
western part of the basin is part of the middle Rocky Mountains physiographic
province; the eastern section is located in the northern Great Plai.ns (Rocky
Mountain Association of Geologists 1972).
THE CONFLICT
Historically, agriculture has been Montana's most important industry. In
1975, over 40 percent of the primary employment in Montana was provided by
agriculture (Montana Department of Community Affairs 1976). In 1973, a good
year for agriculture, the earnings of labor and proprietors involved in
agricultural production in the.fourteen counties that approximate the
Yellowstone Basin were over $141 million, as opposed to $13 million for
mining and $55 million for manufacturing. Cash receipts for Montana • s
agricultural products more than doubled from 1968 to 1973. Since that year,
receipts have declined because of unfavorable market conditions; some
improvement may be in sight, however. In 1970, over 75 percent of the
Yellowstone Basin's land was in agricultural use (State Conservation Needs
Committee 1970). Irrigated agriculture is the basin's largest water use,
consuming annually about 1.5 million acre-feet (af) of water (Montana DNRC
1977).
There is another industry in the Yellowstone Basin which, though it con-
sumes little water now, may require more in the future, and that is the coal
development industry. In 1971, the North Central Power Study (North Central
Power Study Coordinating Committee 1971) identified 42 potential power plant
sites in the five-state (Montana, North and South Dakota, Uyoming, and
Colorado) northern Great Plains region,-21 of them in Montana. These plants,
all to be fired by northern Great Plains coal, ~10uld generate 200,000 megawatts
(mw) of electricity, consume 3.4 million acre-feet per year (mmaf/y) of water,
and result in a large population increase. Administrative, economic, legal,
1
and technological considerations have kept most of these conversion facilities,
identified in the North Central Power Study as necessary for 1980, on the
drawing board or in the courtroom. There is now no chance of their being
completed by that date or even soon after, which will delay and diminish the
economic benefits some basin residents had expected as a result of coal
development. On the other hand, contracts have been signed for the mining
of large amounts of Montana coal, and applications have been approved not
only for new and expanded coal mines but also for Colstrip Units 3 and 4,
twin 700-mw, coal-fired, electric generating plants.
In 1975, over 22 million tons of coal were mined in the state, up from
14 million in 1974, 11 million in 1973, and 1 million in 1969. By 1980, even
if no ne\'J contracts are entered, Montana•s annual coal production will exceed
40 million tons. Coal reserves, estimated at over 50 billion economically
strippable tons (~lantana Energy Advisory Council 1976), pose no serious con-
straint to the levels of development projected by this study, which range
from 186.7 to 462.8 million tons stripped in the basin annually by the year
2000. Strip mining itself involves little use of water. How important the
energy industry becomes as a water user in the basin will depend on: 1) how
much of the coal mined in Montana is exported, and by what means, and 2) by
what process and to what end product the remainder is converted within the
state. If conversion follows the patterns projected in this study, the energy
industry will use from 48,3~0 to 326,740 af of water annually by the year 2000.
A third consumptive use of water, municipal use, is also bound to
increase as the basin population increases in response to increased employment
opportunities in agriculture and the energy industry.
Can the Yellowstone River satisfy all of these demands for her water?
Perhaps in the mainstem. But the tributary basins, especially the Bighorn,
Tongue, and Powder, have much smaller flows, and it is in those basins that
much of the increased agricultural and industrial water demand is expected.
Some impacts could occur even in the mainstem. What would happen to
water quality after massive depletions? How would a change in water quality
affect existing and future agricultural ,industrial, and municipal users?
t~hat waul d happen to fish, furbearers, and migratory waterf0\'11 that are
dependent on a certain level of instream flow? Would the river be as
attractive a place for recreation after dewatering?
One of the first manifestations of Montana•s growing concern for water
in the Yellowstone Basin and elsewhere in the state was the passage of
significant legislation. The Hater Use Act of 1973, which, among other
things, mandates the adjudication of all existing water rights and makes
possible the reservation of water for future beneficial use, was followed
by the l~ater Moratorium Act of 1974, \'Jhich delayed action on major
applications for Yellowstone Basin water for three years. The moratorium,
by any standard a bold action, was prompted by a steadily increasing rush of
applications and filings for water (mostly for industrial use) which, in two
tributary basins to the Yellowstone, exceeded supply. The DNRC's intention
during the moratorium was to study the basin•s water and related land
resources, as well as existing and future need for the basin•s water, so that
2
YEllowsTONE RIVER BASIN
0 10 20 40 60 80 100 Miles LJ-Ui.J I I I I I
0 10 20 40 60 80 100 Kilometers ~ I I I I
I MUSSELSHELL I
GOLDEN\
WHEATLAND I
I
-------~-J VALLEY
I ;------~-
L_
I
l
CARBON
--------'1 ----------~,------
y E L L 0 W S T 0 N E ')
NATIONAL PARK (
N YELLOWSTONE
RIVER BASIN
McCONE
I r
GARFIELD
-----1
.,\TREASURE
WYOMING-
PRAIRIE
I
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POWDER I
ASHLAND
I
I
----~
Tongue River 1
Reservoir \
----,
I
DAWSON
'
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.... ~ 1 ~ ,
GLENDIVE)
J --J
,.
---~-WIBAUX
'tJ > ~
0
~ > I
' (/) . ,g
\;
'S
-..&.1-----------~~~-
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the state would be able to proceed wisely with the allocation of that water.
The study which resulted in this series of reports was one of the fruits of
that intention. Several other Yellowstone water studies were undertaken
during the moratorium at the state and federal levels. Early in 1977, the
45th Montana Legislature extended the moratorium to allow more time to con-
sider reservations of water for future use in the basin.
THE STUDY
The Yellowstone Impact Study, conducted by the Water Resources Division
of the Montana Department of Natural Resources and Conservation and financed
by the Old West Regional Commission, was designed to evaluate the potential
physical, biological, and water use impacts of water withdrawals and water
development on the middle and lower reaches of the Yellowstone River Basin in
Montana. The study's plan of operation was to project three possible levels
of future agricultural, industrial, and municipal development in the
Yellowstone Basin and the streamflow depletions associated with that develop-
ment. Impacts on river morphology and water quality were then assessed,
and, finally, the impacts of altered streamflow, morphology, and water
quality on such factors as migratory birds, furbearers, recreation, and
existing water users were analyzed.
The study began in the fall of 1974. By its conclusion in December of
1976, the information generated by the study had already been used for a
number of moratorium-related projects--the EIS on reservations of water in
the Yellowstone Basin, for example (Montana DNRC 1976). The study resulted
in a final report summarizing all aspects of the study and in eleven
specialized technical reports:
Report No. 1
Report No. 2
Report No. 3
Report No. 4
Report No. 5
Report No. 6
Report No. 7
Future Development Projections and Hydrologic Modeling in
the Yellowstone River Basin, Montana.
The Effect of Altered Streamflow on the Hydrology and
Geomorphology of the Yellowstone River Basin, r·1ontana.
The Effect of Altered Streamflow on the Water Quality of
the Yellowstone River Basin, Montana. ·
The Adequacy of Montana's Regulatory Framework for Water
Quality Control
Aquatic Invertebrates of the Yellowstone River Basin,
Hontana.
The Effect of Altered Streamflow on Furbearing r~ammals of
the Yellowstone River Basin, Montana.
The Effect of Altered Streamflow on Migratory Birds of the
Yellowstone River Basin, Montana.
5
Report No. 8
Report ilo. 9
Report No. 10
Report No. 11
The Effect of Altered Streamflow on Fish of the
Yellowstone and Tongue Rivers, Montana.
The Effect of Altered Streamflow on Existing Municipal
and Agricultural Users of the Yellowstone River Basin,
Montana.
The Effect of Altered Streamflow on Water-Based Recreation
in the Yellowstone River Basin, Montana,
The Economics of Altered Streamflow in the Yellowstone
River Basin, Montana.
ACKNOWLEDGMENTS
Parts I and II of this report we~e written by different authors at
different times and for different purposes.· They are included under one
cover here primarily because of similarity in subject matter. Statements made
in either of the parts should be taken as the statements of the author(s) of
that part.only. There are minor discr~p~ncies in analytical methods.between
the two parts, and some repetition, which the editor thought it best to let
remain. Part I of this report was prepared in 1975, using the most appropriate
methods available at that time, so that its conclusions could be used by the
authors of the other reports in this series.
This report was reviewed by and guidance received from John·c. Orth,
Director of the Montana Department of Natural Resources and Conservation;
Orrin Ferris, Administrator of the DNRc•s Water Resources Division; and
Carole Massman, of the DNRc•s Special Staff.
Assistance with Part I of this report came from a variety of sources,
including the U.S. Geological Survey. The Helena office of that agency pro-
vided data for use in the flow duration curves included here. Bill Emmett
and Bob Meade, with the USGS in Denver, reviewed and commented on a draft
of Part I. Ned Andrews, also with the Denver office, provided field assistance
in addition to reviewing the draft report. Connie Bergum, a technician with
the Montana DNRC, assisted in data collection and reduction .. The .. Geologic
History and Stratigraphy .. section of Part I was compiled by Mark Weber,
co-author of Part II of this report, and by Tony VanderPoel. The study of
the geologic character of the Bighorn River before and after the closure of
Yellowtail Dam (pages 32 to 37) was researched and written by Peter Martin
of the Montana Department of Fish and Game as part of his inquiry into the
effects of altered streamflow on furbearing mammals in the Yellowstone River
Basin; the rest of that study is described in Report No. 6 in this series.
His conclusions are his own and not necessarily those of Roy Koch, primary
author of Part I.
With regard to Part II of the report, special thanks are due to Thomas
Bateridge, Mike Coughlan, Tony VanderPoel, and Gary Parry, all from the
University of Montana Geology Department, for their persistent effort in field
mapping and data analysis.
DNRC personnel providing assistance were Peggy Todd and Ronald J. Schleyer,
who performed editing tasks, and Janet Cawlfield, Kris Macintyre, Lynda Howell,
typists. Graphics were coordinated and performed by Gary Wolf, with the
assistance of Gordon Taylor. The cover was designed and executed by D. C. Howard.
6
by
Roy Koch
7
The Yellowstone River provides habitat for both terrestrial and aquatic
organisms~ including furbearing mammals~ migratory birds~ raptors, fish~ and
aquatic insects. Changes in the present flow regime or physical channel altera-
tions would alter the physical environment of the river and directly affect
those species inhabiting it. The magnitude and direction of such changes are
the subjects of this investigation.
Physical river characteristics to be considered include flow regime,
sediment transport, channel pattern, channel slope, bed and bank material, and
geologic history. These are complexly interrelated, and even the identification
of independent and dependent variables is difficult. As a result, rivers are
only now being physically and mathematically modeled, and with difficulty.
Since even these models are unlikely to provide the information required for
this study, an approach combining what quantitative tools exist with the
abundance of qualitative observations and information documenting river pro-
cesses and changes would seem to be the most helpful. The following report
combines information on the geology, hydrology, sediment transport, and other
geomorphic characteristics of the Yellowstone and its major tributaries to
provide estimates of the impacts of projected ~ater use on the morphology
of the stream channels.
The major emphasis of this investigation was limited to the Yellowstone
River from Billings, Montana, to the confluence of the Yellowstone with the
Missouri River near the Montana-North Dakota border. The major tributaries in
this reach, the Bighorn, Tongue, and Powder rivers, were also considered,
though not in such detail.
9
The lower Yellowstone River Basin is mostly underlain by soft, flat-
lying rock of Terttary age, in particular, the Fort Union Formation. This
formation vari·es i'n thickness from 125 to 1500 feet (40 to 460 m) and is
composed of alternating beds of sandstone, shale, li'gnite, and red clinker.
As shown in figure 2, there are two major structural features in the
study area--the Cedar Creek anticline and the Porcupine Dome. The Cedar
Creek Anticline is a northwest-southeast trending feature whose axis runs
from Glendive to Baker. The northern tip crosses the Yellowstone mainstem
near Glendive. Three lithologies are exposed as a result of the folding:
the Hell Creek Sandstone, the Fox Hills Sandstone, and the Pierre Shale--
all of Upper Cretaceous age. The Porcupine Dome, located north of Forsyth,
has a center composed of Colorado Shale of Middle Cretaceous age. The
exposed strata then progresses through the Eagle Sandstone, Clagett Shale,
Judith River Sandstone, Bearpaw Shale, and Hell Creek Sandstone--all of the
Upper Cretaceous--and the Fort Union of the Tertiary. Only the Hell Creek
Sandstone and Bearpaw Shale underlie the Yellowstone River.
Today, the Rocky Mountains are the eroded cores of rock masses that
were pushed upward about 70 million years ago, partially buried in their
own, water-worn detritus, and then reexposed by the action of water and
ice during a period of excavation which has lasted to the present. A series
of planar landforms is preserved in the Yellowstone drainage basin, the relics
of ancient landscapes which achieved temporary stability during this latest
cycle of erosion which began when the ancestral Rockies were partially buried
in debris.
Some of the larger mountain ranges in the Yellowstone watershed, the
Beartooths, the Crazys, the Bighorns, and the Owl Creeks, are composed of
crystalline rocks at the cores and flanked with Paleozoic and Mesozoic rocks
which have commonly been tilted and broken by the mountain-building process.
The Bighorn, Tongue, and Powder river basins, constituting a significant
part of the lowlands of the Yellowstone drainage, are surfaced by relatively
soft sands, shales, and coal beds deposited when the whole region lay
close to sea level in late Cretaceous and early Tertiary time, some 60 to
70 million years ago. Many of these rock units contain volcanic detritus
of the then-newborn mountains surrounding them and to their west.
Fossil evidence suggests that the early Tertiary relief of the region
was low compared with that of the present. A change in the character of the
sediments in the Great Plains suggests that later, about 40 million years
ago, in Eocene or Oligocene time, an increasingly arid climate developed,
interpreted by Mackin (.1937) as resulting from a broad, regional uplift of
the Rocky Mountains that established strong eastward gradients for mountain
streams and caused widespread aggradation. Alden (1932) contends that, during
an' 01 i gocene-Mi ocene interva 1, a. gravelly surface 'known as the_ Cypress Plain
existed i'n southern Canada, northern Nontana, and possibly the Yellowstone Basin.
Still later, during the Pliocene period (11 to 3 million years ago), gravels
ll
spread outward fro.m the mountainous r.egi.ons to form nearly planar landforms that
may have resembled the modern landscapes in the ari.d valle.ys of the Southwest.
It is the eroded remnants of these arid Terti.ary landscapes that now form the
highest benches in the Yellowstone Basin, along· the mountain fronts and the
river. ·
These Pliocene gravels probably represent the last stage of prolonged,
regional aggra,dati.o'n before the onset of the fluctuattng climate of the
Pleistocene that allowed temperate periods to alternate with periods of
glacial advance in both the northern mountains and the plains (Richmond 1965,
Lemke et al, 1965}, During the last three million years, the dominant
geomorphic activity has been basi.n excavation, that removed thousands of
feet of sediment and, in the process, lowered the Bighorn River onto the
Bighorn and Owl Creek mountains so that its present course cuts di~ectly
through the crystalline rocks. At intervals, the valleys of mountain
streams were aggraded with outwash from alpine glaciers, only to be reincised
when stream loads were reduced in relation to discharge following deglaciation.
The remnants of this process may be seen as a series of terraces in the valleys
of most of the streams that experienced glaciation in their headwaters (Thorn
et al. 1935, Alden 1932, Mackin 1937, Ritter 1967, and Moss and Bonini 1961).
Not all the stream terraces in any valley are paired. In many instances, the
higher landforms on the plains bordering the mountain fronts are capped by the
gravels of streams that now flow several miles from their earlier courses.
This topographic inversion is felt to be the result of (1) the greater eroda-
bility of the soft tertiary bedrock than of the permeable stream gravels of
their former beds, and (2) the process of stream capture, which suddenly filled
low-gradient streams of the plains with the sediment loads of higher-gradient
mountain watercourses (Mackin 1937, Ritter 1967). ·
Although several authors have written on the geomorphic history of
physiographic subdivisions of the Yellowstone Basin, to date no one has pro-
duced a comprehensive treatment. W. C. Alden, who is included in the
bibliographies of almost every writer concerned with the geomorphology of
eastern Montana, made the first attempt to correlate and date the major
features of the area on a broad scale. Though requiring some major revisions
on the strength of more recent investigations, his original heirarchy of the
geomorphic surfaces still serves as a standard for comparison.
Many of Alden•s concepts of geomorphology accomodated those of W. M.
Davis, whose theoretical stages of landscape evolution postulated peneplains
as the representation of old age. At the time that Alden wrote, Eliot
Blackwelder (1915) and Arthur Bevan (1925) had published papers that described
two planar erosion surfaces in the heights of the Wind River and Absaroka ranges
at approximately 9,000 to 12,000 foot elevation. Correlating these with other
high-level surfaces in the Rocky Mountains, they named these the summit and
subsummit peneplains. Drawing on the work of Willis (1902) and Collier and
Thorn (1918), Alden used the name Cypress Plain for a prominent erosion surface
preserved in northcentral Montana, southern Alberta, and Saskatchewan. This
surface is capped with gravels dated 01 igocene by the presence of foss i1 s
that include crocodile~, horses, rhinoceroses, and titanotheres. Although
lacktng any local fossil material for dating, Alden tentatively correlated
several anomalously high stream gravel depos·its in the Yellowstone Basin to
this landform. One ~rea wHere ~he~e infer~edly Cypress-age gravels are
preserved in on the top of Pine Ridge, between the Bighorn and Yellowstone
rivers east of Billings, where th~ Upper-Cretaceous Lance Sandstone forms
12
YEllowsTONE RIVER BASIN
GENERAliZEd
RIVER BASIN
GEoloqy of ThE YEllowsTONE
D Quaternary Alluvium
Tertiary Sediments
Cretaceous-Tertiary Intrusive Rocks
Cretaceous-Tertiary Extrusive Rocks
Mesozoic Sediments Undifferentiated
Paleozoic Sediments Undifferentiated
Precambrian Metamorphic and
Intrusive Complexes
0 10 20
I
40
I
60
I
80
I
100 Miles u-u-u
0 10 20
IHHH
40
I
60
I
WHEATLAND
YELLOWSTONE \
)
NATIONAL PARK I
(
80
I
100 Kilometers
I
I
GOLDEN \
I
MUSSELSHELL
N YELLOWSTONE
RIVER BASIN
GARFIELD
WYOMING
McCONE
I
(
-----,
--
' _,
~--
steep escarpments 1,100 feet above the rivers. Alden attempted to correlate
the gravels on Pine R~_dge with the supposed subsummi~ peneplain i~ the
Beartooths on t~e basts of recon~tructed stream grad1ents, but th1s
hypothesis requtres either excessively high -gradients in the upper reaches
or subsequent differenti'al upHft of the mountains and basins, the validity
of which has not been established. Alden dtd establish, however, that the
Pine Ridge gravels are reasonably old and that they were deposited by high-
energy streams since the deposits include cobbles up to 8 inches in diameter.
On the basis of physiographic position, Alden considered the Tatman
Mountain gravels in the Bighorn Basin in Wyoming to be of similar age. Also
in the Bighorn Basin, Northern Wyoming's Polecat Bench was correlated with
the Cypress Plain surface north of the Pryor Mountains on the basis of a
reconstructed drainage profile. Thorn et al. (1935), in collaboration with
Alden, speculated that the eastward-sloping, truncated surface of the Rosebud
and Wolf mountains may have been formed as a part of this surface though not
serving as a site of deposition.
Following the development of the Cypress Plain, Alden inferred that
differential uplift initiated a cycle of erosion which resulted in 700 to
1,500 feet (200 to 450 m) of dissection of the land surface on the plains
and 2,000 to 3,000 feet (600 to 900 m) of dissection in the mountains.
Below the level of the Cypress Plain, gravel-capped surfaces or benches were
interpreted to represent successive cycles of aggradation that interrupted
the regional pattern of degradation. The uppermost and oldest of these
gravel benches was correlated with the Flaxville gravel in northeast Montana
named by Collier and Thorn (1918). Alden designated this relic surface the
No. 1 Bench. The deposits of this bench have been found to contain fossils
of Miocene and Pliocene fauna including three-toed horses, horned gophers,
rabbits, rhinoceroses, creodonts, camels, and saber-toothed tigers. In
addition, Collier and Thorn found what may be the tooth of a Pleistocene camel,
leaving the deposit's age assignment open to interpretation. Below the No. 1
Bench, Alden recognized the No. 2 and No. 3 benches of supposed early and
late Pleistocene age, separated from one another by a vertical interval of from
100 to 200 feet (30 to 60 m). These landforms~ while truncating consolidated
rocks of both the Mesozoic and Tertiary, are not strictly erosional feastures
since all are capped with veneers of gravel of varying degrees of consolidation
which locally reach a thickness greater than 100 feet (30m). Alden's chronology
for the erosion surfaces in the northern Great Plains is summarized in
table 1.
TABLE 1. Assumed chronology of erosion surfaces in the northern Great Plains.
Cypress Plain
Flaxville Plain or
No. 1 Bench
No. 2 Bench
No. 3 Bench
SOURCE: Modified from Alden (1932)
Oligocene-Miocene (?)
Pliocene (? possibly Pleistocene)
Early Pleistocene (probably pre-
Kansa n or Kansan)
Late Pleistocene (Possibly Illinoian)
NOTE: Modifying information derived from subsequent work in parentheses
15
The No. 1 Bene~ of Alden is well represented in the Yellowstone drainage;
prominent examples are found bordering Rock Creek. on the.~outhwest flank of the
Crazy Mountatns, adjacent to the Boulder River near Big Timber, along the
Beartooth Mountain front near Red Lodge and Roscoe, along the northeast flanks
of the Pryor and Bighorn Mountains (parti'cularly along the Bighorn River) and
on several interfluvial ridges south of the Yellowstone River near Hysham
and Forsyth. Further easi, remnants of the No, 1 Bench cap an extensive area
north of Glendive and south of the furthest extent of the Keewatin glacial
drift which mantles the same surface north of the Missouri River.
The No. 2 and No. 3 benches are represented along most of the glaciated
mountain streams as two sets of terraces, not always differentiable, though
usually separated by 100 to 200 feet (30 to 60 m) of elevation. These distinct,
important landforms are often several miles wide along the Yellowstone mainstem
and constitute some of the most productive agricultural land in the area. Alden,
as well as many other investigators, noted the relationships of many of these
terraces to morain~s in the mountain canyons. Although the evidence for
Pre-Wisconsin advances of the mountain glaciers in this area had not been con-
clusively demonstrated at the time, Alden concluded that the second set of
terraces along the Yelowstone River was capped with gravels deposited when
the Kansan advance of Keewatin ice obstructed the drainage. In addition, he
speculated that it was this glacial advance which diverted the Yellowstone and
Missouri southward from their former drainage into Hudson Bay. The third
set of terraces was thereby inferred to be correlative with the Illinoian
advance, leaving the modern valley bottom fill as a product of the Wisconsin.
Rejecting the concept of peneplanation, Mackin (1937) suggested that
pedimentation and its requisite lateral corrasion were the formative process
for features such as the higher level gravel deposits of the Bighorn Basin.
Mackin also inferred that cryoplanation or altiplanation were significant
forces in the evolution of the highest erosion surfaces in the mountains
and concluded that the summit surface was more likely of Pleistocene origin
than mid-Tertiary. Mackin stressed the importance of graded streams and
of stream capture in the evolution of many of the region's watersheds as well
as the role that variations in climate and discharge have had upon the
downcutting capacity of the streams.
More recently, work on the Cody and Powell terraces of the Shoshone River
by Moss and Bonini (1961) has shown that not all of Mackin's interpretations
of the formative processes of stream terraces were correct. Using geophysical
methods, they showed that the bedrock beneath the terraces was not thoroughly
planed by the lateral cutting action of the stream before gravel was laid on
top, as the most simplistic interpretation of Mackin's explanation might lead
one to believe. The Cody and Powell terraces must therefore be considered
alluvial terraces rather than rock-cut terraces. A significant part of the
value 6f their work appears to lie in illustrating the value of geophysical
techniques, parti.cularly seismic refraction, in geomorphic studies.
Ritter (1967} described the distribution and composition of terraces of
several streams near and including Rock Creek. Using analytical techniques
and a rationale similar to that of Macki'n, he demon.strated the importance
stream capture and preferential erosion of the soft bedrock in the evolution
of the mountain-front landscape. Ritter also concluded that the mountain-
front streams now drain in a more northerly course than they did during the
deposition of the highest benches, equivalent to Alden's No. 1 Bench.
16
In hi.s discussion qf the age of the landforms i.n the Bighorn Basin,.
Macki_n (1937} took. i.ssue with. the techniques used by Alden (.19.32) in correlating
the age -of landfor11_1s on the basi.s of ph.yiiiographic positton, particularly their
heights above watercourses. In refe~ence to the g~avels on Tatman Mountain, the
highest planar surface in the basin proper, he disagreed with Alden's correlation
with the Cypress Plain because the plain's lower elevation required it to be
younger than the Tatman Mountain subsurmnit erosion surface considered
Pliocene by Bevan (1925) and Blackwelder (1915). He further criticized the
age assignment of Oligocene for the surface of the Cypress Plain, noting that
Oligocene gravels might well have been beveled at a later date. More recently,
Rohrer and Leopold (1963) demonstrated that the uppermost of the Tatman
Mountain gravels contain a Pleistocene or·upper Pliocene palynological suite.
Only the northeastern reaches of the Yellowstone River in Montana were
directly affected by conti"nental ice during the Pleistocene, when at. least one
lobe extended southward to the location of the town of Intake. Alden (1932) and
Howard (1960) describe the flooding of the Yellowstone Valley by glacial Lake
Glendive to a distance of at leait 15 miles south of the modern town of Glendive
during an early Wisconsin advance.
17
The present-day alluvial channel of the Yellowstone River is the result
of the river•s history and of man•s impact on the river and watershed. A profile
of the lower Yellowstone River from Billings to Sidney is shown in figure 3.
No abrupt changes in slope can be noted, indicating that there is no overloading
of the mainstem by sediment of the tributaries. There is, however, some out-
cropping of bedrock in the channel bed and banks at several points in the reach
from Miles City to Fallon. This reach of the river, apparently stable with the
slope imposed by bedrock, is incised into the lacustrine deposits of the
ancestral Glacial Lake Glendive. This reach may dictate the slope of the river
above and below.
CHANNEL FORM
YELLOWSTONE MAINSTEM
The general character of the Yellowstone is the same today as it was when
Captain William Clark traveled the river in the summer of 1806; that is, those
reaches of the river that were braided with wooded islands still show that
character, and those reaches where there were no islands and only a few
gravel bars still show that character. The form of the Yellowstone River
varies throughout its length, seemingly in relation to the river valley.
The valley is variable in width, ranging from less than a mile where rock
terraces confine the valley, such as near Billings and Forsyth, to nearly four
miles where the alluvial valleys of several smaller drainages intersect the
mainstem, such as the Mission Valley below Hysham. In general, when the river
flows along a valley wall, it will continue to follow the wall until the
valley changes direction. The river then continues along the previous course
until it meets the opposite valley wall, and the circumstances are repeated.
It is along the reaches where the river is not directed by a valley wall
that it is free to develop and change its form.
In order to characterize the river, five reaches (figure 4) which repre-.
sent five forms seen along the river have been selected:
1. Huntley to Pompey•s Pillar, 19.9 mi (32.0 km)
2. Mouth of Bighorn to mouth of Froze-to-Death Creek, 24.9 mi (40.1 km)
3. Near Hathaway to above Miles City, 19.2 mi (30.9 km)
4. Buffalo Rapids to below Terry, 18.4 mi (29.6 km)
5. Intake to Savage, 17.0 mi (27.4 km)
In order to adequately descr1be these reaches, the description of such factors
as channel length, channel slope, bed material, sinuosity, the ratio of the
channel length to down-valley distance, type of lateral activity, and bankfull
discharge (assumed to be the discharge with channel-forming properties) is
required.
19
3100
3000
2900
2800
2700
-2600
_J
(/)
~~ 2500 -Q)
Q) --2400
c:
N 0 0 ....
0 2300 >
Q)
w
2200
2100
2000
1900
1800
~USGS Gaging Station 6-2145 at Billings
/~USGS Gaging Station 6-2175
LHuntley
Project
Diversion
Dam
River
rHighwoy 12 Bddgo ot Fo,yth
USGS Gogi,g Stotio" 6-2950__/
rRosebud Creek
rUSGS Gaging Station 6,-3090 at Miles City
Tongue River_/ 1( ___! _/Powder River
Ki""' P"mpi"g Coool r r-Highwoy 10 Bddgo ol Folio"
__I /Highway 10 Bridge at Glendive
Highway 253 Bridge at Terry f \Intake Diversion Dam and Headgote
Interstate 94 Bridge. at Glen.dive~ t. ....~ y--Highwoy 16 Bridge near Savage
USGS Gagmg Stot1on 6-3275 -!! fDNRC Pumping Station
USGS Gaging Station 6-3285 ~
USGS Gaging Station 6-3292 J .
Smith Creek
Highway 23 Bridge near Sidney
380 360 340 320 300 280 260 240 220 200 180 160 140 120 100 80 60
River Miles
40 20
Figure 3. Profile of the Yellowstone River Mainstem between Billings and Sidney.
0
YEllowsTONE RIVER BASIN
·F1vE REpRESENTATIVE REAchEs of ThE
YEllOWSTONE RIVER
0 10 20 40 60 80 100 Miles u--u-u I I I I I
0 10 20 40 60 80 100 Kilometers . UWJ--1 I I I I
I MUSSELSHELL I .
GOLDEN\
I
WHEATLAND I
I -------c--J VALLEY
I ,....------~~
L_ ~--"'
I
l
I
I
. I
l,
I
_j CARBON
I
-1 _j
-------'1 --~--- --+,---'--
y E L L 0 W S T 0 N E ')
NATIONAL PARK (
N YELLOWSTONE
RIVER BASIN
GARFIELD
WYOMING
McCONE
----
POWDER
BROADUS
.. ~
~0
•
e(
----,
I
DAWSON
,
• GLENDIVE)
J
J
' _,
A few of the terms to be employed in the following discussion should be
explained. A classification of river form and process presented by Kellerhals
et al. (1975) involves the identification of the following:
1) flood plain, alluvial terraces, and the valley floor
2) relation between the river channel and its valley, and
3) the channel description
The last two of these characteristics are the most important for the present
analysis.
The relation of the river to its valley implies an analysis of the
relation of the channel to the valley floor and to the valley walls, i.e.,
Is the river aggrading or degrading? Are the walls influencing channel
pattern by confining the river?
The description of the channel is most important in this study and involves
the classification of channel pattern, islands, channel bars, and lateral
channel activity. Each of these characteristics, illustrated in figure 5,
can help to identify the forces presently at work in the river. Three channel
patterns occur in the Yellowstone: sinuous, irregular, and irregular meanders;
the river tends more toward a braided than a meandering stream. Islands, stable
features at the same elevation as the valley floor, are important to the river
ecosystem. Channel bars can be either stable or ephemeral ·features depending
on bed material. In the Yellowstone, the midchannel bars typical of large,
gravel-bed channels are prevalent, as are alternating or lateral bars occurring
at the bends in the sinuous reaches of the river. These bars can remain in
position for many years with transport of bedload occurring over the bar
(Kellerhals et al. 1975). Finally, lateral channel activity can indicate the
stability and character of the river. Irregular activity, in which the main
ch9nnel occasionally changes course, is common in active gravel-bed streams
such as the Yellowstone.
A summary of the major geomorphic characteristics of the five study reaches
in the lower Yellowstone and of its three major tributaries is presented in
table 2. A short description of each reach follows.
Reach 1
The section of the river from Huntley (river mile 349, river kilometer 561)
to Pompey's Pillar (river mile 329, river kilometer 529) appears to be char-
acteristic of the middle Yellowstone River (figure 6). In this reach, the
river follows the north valley wall for most of the distance, deviating only
for four miles directly below Huntley. The channel pattern is sinuous where
controlled by the valley wall and irregular where uncontrolled. Sinuousity.
averages 1.14 through the reach. Islands occur frequently. Several types
of channel bars occur, indicating active bed material transport. Junction bars,
some small, occur at the confluence of each small creek, formed by the deposition
of the creeks' sediment load. Side bars, the counterpart of point bars .in
a meandering channel, also occur. Midchannel bars occur infrequently, and a
few diamond bars, large midchannel bars, are apparent. That lateral activity
in the reach is classified as irregular due to the prevalence of chutes, side
23
Straight
Sinuous
Irregular
Irregular Meanders
Channel Pattern
Channel Side Bar
~
~
Channel Junction Bar
Point Bar
Midchannel Bar
Channel Bar Form
Occasional: no overlappinQ of islands, overaoe spocino ten or more river widths
Frequent : infrequent overloppino, averaoe spocino less than ten river widths
Split I islands overlap frequently or continuously, number of flow choMels
usually two or three
Braided: many channels divided by river ban and islands
Island Occurrence
Meander Progression and Cutoff
Entrenched Loop Development
Irregular
Channel or SlouQh
lateral Activity
SOURCE: .1\dopted from Ke 11 erha 1 s et a 1 . 1076.
Figure 5. Characteristic forms of the Yellowstone River Channel.
24
N
U1
-~
NOTE: Not all of Reach 1 is shown; rather,
this is a representative section ~f it.
River Channel
~---------Gravel Bars
ilfl/ll/1/illll/i/i/1111/llll/1/il//i/i/1 Valley Wall
0 2 Miles
0 2 Kilometers
Figure 6. Reach 1: the Yellowtone River from Huntley to Pompey's Pillar.
TABLE 2. Geomorphic characteristics of the middle and lower Yellowstone River
Basin and major tributaries.
River
Reach
1
2
3
4
5
Bighorn River
at Bighorn
Tongue River
at Miles Ci (yd
Powder Rivea
near Locate
Reach
Length
19.9
24.9
19.2
18.4
17.0
Average
Slope
0.0014
0.00058
0.00067
0.00058
0.00046
0.0013
0.0019
0.0011
CONVERSIONS: 1 mm = .0394 in
Average
Sinuosity
1.14
1.36
1.24
1.27
1.17
NAc
1.7
1.2
1 cfs = .0283 m3/sec
aEstimated as the 1.5-year flood
bEstimated based on drainage area
cNot avail ab 1 e
dschumm (1969)
Bed Material Bankfull
d5o (mm) Dischargea
(cfs)
21 34,500b
38 45,000
19 47,000
18.5 5l.ooob
22 52,ooob
NAc 12 '700
1.9 3,080
3.6 6,800
channels, and backwater areas is typical of active gravel-bed rivers and indicates
shifts in the position of the main channel (Kellerhals et al. 1975).
Reach 2
This reach extends from the confluence of the Bighorn and Yellowstone rivers
(river mile 296, river kilometer 476) downstream to the confluence of Froze-to-
Death Creek and the Yellowstone (river mile 270, river kilometer 434) (figure 7).
The valley line in this reach is irregular, changing in direction from east to
north and back to east and in width from 1.2 mi (1.9 km) to 4 mi (6.4 km). The
channel pattern varies from sinuous to irregular meandering where the channel
is mobile, but no real pattern is evident. The average sinuosity of this
reach is 1.36. Islands are frequent, overlapping head and tail ends in some
instances. Point, midchannel, and diamond bars occur, indicating an active
channel bed. The irregularity of lateral channel activity where the channel is
not controlled by the valley walls would also indicate an active channel bed.
26
River Channel
Gravel Bars
•111WIII~II~IIII~IUIU11IIII Valley Wall
0 2 Miles
0 2 Kilomelers
I.' -.tt------1=:::1..--..,jl
Figure 7. Reach 2: the Yellowstone River from the Mouth
Mouth of Froze-to-Death Creek. of the Bighorn River to the
Reach 3
Along this reach, from near Hathaway (river mile 187.6, river kilometer
301.8) to above Miles City (river mile 168.4, river kilometer 271.0) the river
exhibits a character much different from that seen along the rest of the
river (figure 8). In this reach, the valley is relatively narrow and
irregular in direction, exhibiting a slightly meandering character. The
river itself is more regularly meandering in sections of this reach than
throughout the rest of the river; where the valley wall is controlling the
direction, the channel pattern is sinuous to straight. The sinuosity averages
1.24. Islands are less frequent, with lateral bars occurring along the
sinuous section and point bars in the meandering sections. Midchannel bars
are present but mostly in the straight-to-sinuous section of the reach.
Lateral channel activity is much more regular in the meandering parts of
this reach, exhibiting some meander progression, enlarging, and cutoffs.
There is some irregular lateral channel activity in the sinuous section of
the reach.
Reach 4
This reach (figure 9), which extends from Buffalo Rapids (river mile 150.5,
river kilometer 242.2) to below Terry (river mile 132.3, river kilometer 212.9),
is representative of the river from below Miles City to below Fallon. In this
reach, the river is incised into the flood plain, probably lacustrine deposits
of Glacial Lake Glendive as discussed on page 17 . In addition to the incised
nature of the channel, bedrock outcroppings are prevalent in both the sides
and bottom of the channel, as exemplified by Buffalo Rapids and Wolf Rapids,
both named by Captain Clark during his journey through the reach. It seems
likely that the slope in this reach is determined by the obvious bedrock
constraint. The channel pattern varies from sinuous to meandering. There
are few islands. Midchannel bars exist, as do alternating and point bars.
Probably due to the influence of the bedrock, there is no apparent lateral
channel activity, nor is there any indication of past activity through flood
plain scars or abandoned channels.
Reach 5
This reach, from Intake Diversion Dam (river mile 71.1, river kilometer 114.4)
to Savage (river mile 54.1, river kilometer 87.0) is representative of the
lower section of the river from below Glendive to the mouth (figure 10). For
most of the length of this reach, the river is on the east side of the valley;
it is in contact with the valley wall in several locations. The channel
pattern varies from sinuous to irregular, depending on proximity to the
valley wall. There are many islands, overlapping frequently along their
entire length. Midchannel and diamond bars occur frequently. Lateral
channel activity is irregular, indicating instability of the main channel, a
classic characteristic in active gravel-bed channels, evidenced here by the
presence of numerous chutes and backwater areas.
28
River Channel
Grovel Bars
Volley Well
0 2 Miles
0 2 Kilometers
Figure 8. Reach 3: the Yellowstone River from near Hathaway to above Miles City.
River Channel
Gravel Bars
...... llldl, .. llllllllllllll• Valley Wall
0 2 Miles
·I 2 Kilometers 0
I t==j
Figure 9. Reach 4: the Yellowstone River from above the Mouth of the
Powder River to below Terry.
30
Figure 10.
to Savage.
) ,..,
(
•. /
I f ~-
f I
I :
\
0
0
River Channel
Grovel Bars
Volley Wall
I
'=== 2 Miles
2 Kilometers
Reach 5: the Yellowstone River from Intake Diversion Dam
31
TRIBUTARIES
The geomorphic character of the major tributaries, including the Bighorn,
Tongue, and Powder rivers, is also of interest.
Bighorn River
An important factor affecting streams or rivers is the construction of
reservoirs. These reservoirs trap sediments, releasing clear water downstream
which has the potential to degrade the river channel (Simons 1972). Sediment
moving through a river system is an important variable affecting slope and
sinuosity (Schumm 1972). Besides resulting in the elimination of side channels,
backwater area, sloughs, and islands, reservoir construction also eliminates
peak flows which are instrumental in moving sediments and in the formation
of new islands.
Many changes ha~e taken place in the physical structure of the Bighorn
River since 1939. Several dams have been constructed, two in Wyoming and
one (Yellowtail Dam) in Montana. As part of his study of the effect of
altered streamflow on furbearing mammals in the Yellowstone River Basin
(see Report No. 6 in this series), Peter Martin conducted an extensive
analysis of the Bighorn River in order to determine changes in channel
morphology since the closure of Yellowtail Dam in 1965; the following dis-
cussion of Bighorn River geomorphology was written by him. Photographs taken
in 1939 for that portion of the river in Bighorn County below the afterbay
dam (approximately 71 mi) and in 1950 for the mouth section (approximately
14 mi) were compared to photographs taken in 1974. Overlays of these photographs
depicted vegetated islands, gravel bars, agricultural development, and
riparian vegetation on the river bottom from Yellowtail Afterbay Dam to the
Yellowstone River. Vegetated islands were defined as any vegetated land form
separated from the main valley floor by water or gravel bars. Gravel bars were
classified as 11 island 11 (separated from the valley floor by water) or 11 lateral 11
(adjacent to the valley floor). The areas of these physical features were
measured with a digitized planimeter at the Civil Engineering and Engineering
Mechanics Department of Montana State University, Bozeman.
For ease in interpreting data, the river was divided into five sections
(figure 11):
1) Yellowtail afterbay dam to just above the mouth of Hay Creek,
2) Above Hay Creek to just above Two Leggins diversion dam,
3) Above Two Leggins diversion dam to just below the mouth of dry Creek
4) Below Dry Creek to above the mouth of Pocket Creek, and
5) Above Pocket Creek to mouth
The general statistical results of this investigation are given in table
3. Changes in island and gravel bar numbers and areas are given in table 4.
Islands and gravel bars, divided into size (area) categories, are shown in
tabular and graphical form in appendix B. ·
The river maintained its length and total riparian area .. A 37.6-percent
gain of 3,329 acres (1 ,347.4 ha) of bank riparian area was recorded. A
corresponding loss in river area was noticed, as tabulated in table 5.
32
Base Map from USGS
Figure 11. Bighorn River sections delineated for interpretation of aerial
photographs.
13
TABLE 3. Changes in the Bighorn River channel after construction of Yellowtail Dam
Before After
Section Constructiona Constructi onb Change Percentage
LENGTH OF MAIN CHANNEL IN MILES
1 12.27 12.17 -0.10 -0.8
2 19.55 19.82 +0.27 +1. 4
3 20.05 20.30 +0.25 +1. 2
4 19.48 18.91 -0.57 -2.9
5 13.63 14.77 + 1.14 +8.4
TOTAL 84.95 85.97 +1.02 +1. 2
TOTAL RIPARIAN AREA IN ACRES (EXCLUDES FARM LAND AND OTHER DEVELOPMENT)
1 2,894.27 3,197.41 +303. 14 +10.5
2 5,433.19 5,516.61 +83.42 +1. 5
3 5,846.29 5,486.22 -360.07 -6.2
4 4,474.50 4,458.89 -15.61 -0.3
5 3,546.69 3,470.42 -76.27 -2.2
TOTAL 22,194.94 22,129.55 -65.39 -0.3
TOTAL BANK RIPARIAN AREA IN ACRES
1 1,552.04 2,232.25 +680.21 +43.8
2 2,543.53 3,528.83 +985.30 +38.7
3 1,910.02 2,761.91 +851. 89 +44.6
4 1,255.15 1,981.81 +726.66 +57.9
5 1,590.59 1,675.96 +85.37 +5.4
TOTAL 8,851.33 12,180.76 +3,329.43 +37.6
TOTAL RIVER AREA Ill ACRES (INCLUDES WATER, ISLANDS, AND GRAVEL BARS)
1 1,342.23 985.16 -357.07 -26.6
2 2,889.66 1 ,987. 78 -901.88 -31.2
3 3,936.27 2,724.31 -1,211.96 -30.8
4 3,219.35 2,477.08 -742.27 -23.1
5 1,956.10 1,794.46 -161.64 -8.3
TOTAL 13,343.61 9,948.79 -3,394.82 -25.4
TOTAL VEGETATED ISLAND AND GRAVEL BAR AREA IN ACRES
1 759.56 409.97 -349.59 -46.0
2 1,921.15 979.29 -941 .86 -49.6
3 2,765.53 1,646.43 -1,119.10 -40.5
4 2,090.37 1 ,465. 63 -624.74 -29.9
5 1,022.22 1,056.23 +34.01 +3.3
TOTAL 8,558.83 5,557. 55 -3,001.28 -35.1
TOTAL WATER AREA IN ACRES
1 582.67 575.19 -7.48 -1.3
2 968.51 1 ,008.49 +39.98 +4. 1
3 1,170.74 1,077.88 -92.86 -7.9
4 1 ,128.98 1,011.45 -117.53 -10.4
5 933.88 738.23 -195.65 -21.0
TOTAL 4,784.78 4,411.24 -373.54 -7.8
CONVERSIONS: mi 1.61 km
acre = . 405 ha
aAerial photos of sections 1-4 were taken in 1939, of section 5, in 1950.
bAerial photos taken in 1974
34
TABLE 4. Number, average area, and total area of vegetated islands, island
gravel bars, and lateral gravel bars on the Bighorn River before and after
construction of Yellowtail Dam.
Before Constructiona After Constructionb Area Change
Section Number Average Total Number Average Total Total Percentages
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
Area Area Area (acres)
(acres) (acres) (acres) (acres)
VEGETATED ISLANDS
54 8.5 459.2 42 8.5 355.2 -104.0 22.6
85 15.2 1293.7 84 9.8 823.4 -470.3 36.4
115 18.7 2155.2 56 25.8 1446.7 -708.5 32.9
90 17.4 1567.3 66 20.1 1323.2 -244.1 15.6
70 12.6 884.1 39 24.2 942.0 + 57.9 6.6
TOTAL 414 15.4 6359.6 287 17.0 4890.6 -1469.0 23.1
ISLAND GRAVEL BARS
79 2.8 219.4 42 0.7 30.1 -189.3 86.3
131 3.9 507.9 75 1.3 94.6 -413.3 81.4
183 3.0 548.3 77 1.5 118.6 -429.7 78.4
113 3.8 432.5 61 1.7 102.8 -329.7 76.2
113 0.9 106.0 46 1.5 66.6 -39.4 37.2
TOTAL 619 2.9 1814.2 301 1.4 412.8 -1401.4 77.2
LATERAL GRAVEL BARS
26 3.1 81.0 20 1.2 24.6 -56.4 69.6
40 3.0 119.6 23 2.7 61.3 -58.3 48.7
16 3.9 62.0 28 2.9 81.1 + 19.1 30.8
21 4.3 90.5 22 1.8 39.6 -50.9 56.2
19 1.7 32.1 18 2.7 47.7 + 15.6 48.6
-TOTAL 122 3.2 385.2 111 2.3 254.2 -131.0 34.0
CONVERSIONS: 1 acre = .405 ha
NOTE: Both average and total areas have been rounded to the nearest 0.1 acre.
aAerial photos of sections 1-4 were taken in 1939, of section 5, in 1950.
bAeri a 1 photos taken in 1974. -
35
TABLE 5. Loss in Bighorn River Area following construction of Yellowtail Dam.
Vegetated Islands
Island Gravel Bars
Lateral Gravel Bars
Water Area
TOTAL RIVER AREAa
CONVERSIONS: 1 acre = .405 ha
aDoes not add due to rounding
Acreage Loss
1,469
1,401
131
374
3,374
Percentage Loss
23.1
77.2
34.0
7.8
25.4
The 7.8-percent water area reduction shown in table 5 is significant
because the 2710-cfs flow at the river's mouth on September 30, 1974, the
day the photographs were taken, was 730 cfs higher than the 1980-cfs flow
on August 20, 1939 (Hadfield 1975). The histograms in appendix B show that
the loss in numbers of vegetated islands was highest in the 5.01-to-10.00-
acre (2-to-4-ha)category, with substantial losses in all categories except
in the 3.01-to-5.00-acre (1.2-to-2-ha) and over-100 acre (40-ha} ranges.
Island gravel bar numbers decreased dramatically (619 to 301 overall} in all
categories. The larger bars suffered the highest losses; the percentage of
bars less than 2.00 acres (0.8 ha) increased from 80 to 90 percent of the
total. The large lateral gravel bars were also reduced in number. The
reduction in numbers of vegetated islands, island gravel bars, and lateral
gravel bars was accompanied by a reduction in the average size of gravel
bars and an increase in the average size of vegetated islands. This ca~ be
explained by the combining of small islands and gravel bars into larger
islands as degradation lowered the channel and water level. Stable flows
allowed vegetation invasion of gravel bars, further reducing gravel bar areas.
In section 1, immediately downstream from Yellowtail Dam, the number of
vegetated islands decreased from 54 to 42. The area of the islands decreased
22.6 percent from 459 to 355 acres (186 to 144 ha). Bank riparian area
increased 43.8 percent as former islands and gravel bars were eliminated.
The area of island gravel bars decreased 86.3 percent, as 189 acres (77 ha} of
island gravel bars were lost. Fifty-six acres (23 ha) of lateral gravel bars
were lost (69.6 percent of the 81 acres present in 1939}. The total river
area, which includes island, gravel bar, and water surface area, decreased
from 1342 to 985 acres (543 to 399 ha}, a loss of 27 percent. The makeup
of vegetated islands (figures B-1 and B-4 of appendix B) in section 1 reveals
the overall loss in numbers in the 1.01-to-2.00-acre (0.4-to-0.8-ha}, 5.01-
to-10.00-acre (2.0-to-4.0-ha) and 10.01-to-20.00-acre (4-to-;8 ha) categories.
All of the medium and large island gravel bars (those over 2 acres) except one
were lost. Lateral gravel bars followed the same pattern; only two of the 18
bars over two acres remained in 1974.
36
The other four river sections had similar changes. Section 3 had the
greatest loss of riparian area (360 acres br 146 ha--6:2 percent). Section 4
gained the highest percentage of bank riparian area {57.9 percent), while
section 2 gained the most acreage {985 acres, or 399 ha}. Section 2 lost the
highest percentage of river area {31.2), but section 3 lost the most acreage
(1,212 acres, rir 491 ha}. Section 5, the furthest from the dam and theoretically
the area least affected, demonstrated small changes in all categories except
water area where it registered a 21.0 percent loss. Island gravel bar
losses seemed_to be most directly related to distance from the dam, in
that section 1 had the highest loss at 86.3 percent and each successive
section had a lower loss down to 37.2 percent in section 5. Lateral gravel
bars actually increased in section 3 (31 percent}, perhaps influenced by the
sediment inflow from the Little Bighorn system, and section 5 (49 percent),
possibly because of sediments moved from upstream sections.
Tongue River
The Tongue River in Montana is controlled by Tongue River Reservoir.
Below the reservoir, the river flows for about 10 mi (16 km) through a steep-
walled, sinuous canyon just wide enough for formation of a narrow flood plain.
Below this canyon, the valley widens and meanders across a much wider flood
plain to its confluence with the Yellowstone River at Miles City. The form
of the Tongue River below the canyon is irregularly meandering with most
of the lateral channel activity confined to meander formation and cutoff.
Channel bars and islands are few, occurring only occasionally below where
a bend is eroding a valley wall of gravel. Bovee (1975} describes the bed
of the Tongue River as being completely armored from below the dam to near
the town of Birney. From Birney to near the Brandenburg Bridge, the bed is
armored in spots. Below Brandenburg, the bed appears to be in equilibrium,
more characteristic of an alluvial stream. Bulk samples of bed material
were collected at several points along the river, dried, and sieved. The
data are presented in table 6.
TABLE 6. Bed material of the Tongue and Powder rivers, Montana
Station d5o(mm) a90 (mm)
TONGUE RIVER
near Mi 1 es City 1.9 14
at SH Ranch 43.5 57
below Brandenburg Bridge 1.7 11
at Ashland 21.5 40
POWDER RIVER
near Locate 3.6 42
at Moorhead 8.6 58
CONVERSIONS: 1 mm = .0394 in
NOTE: This table is based on bulk samples of surface bed material.
37
Powder River
The Powder River has been characterized since its settlement as 11 a mile
wide and an inch deep, too thick to drink, and too thin to plow'' because of
its shallow, heavily sediment-charged waters. In general, the Powder flows
through a relatively wide valley for most of its length. However, for
approximately 25 mi (40 km) from its confluence wiih the Yellowstone upstream,
it is incised from 20 to 50 ft (6 to 15 m) into the flood plain, probably as a
result of a change in base level when Glacial Lake Glendive disappeared.
Throughout its length, the river is either sinuous or irregularly meandering.
Lateral activity is irregular with a few cutoffs in the more meandering
reaches. There are many midchannel bars; many are ephemeral, occurring only
at high flows, and many appear at low flows in the main channel as a result of
the shifting bed. Islands are not prevalent in the Powder River. Data on
bed material size of the Powder are presented in table 6.
COMPARISON WITH OTHER RIVERS
-Based upon the discussion of channel form presented above, a comparison
between the existing characteristics of the river and those of other rivers in
the country would be enlightening in that such a comparison would point up
any anomalous characteristics of the river. Leopold and Wolman (1957) have
presented a channel-form relationship based on slope and bankfull discharge
as shown in figure 12. Based on many data representing wide ranges of flow,
drainage areas, and bed materials, this relationship was constructed using the
criteria that channels with a sinuosity greater than 1.5 are meandering;
those with sinuosity less than 1.5 are braided or straight. As can be seen
from figure 12, the majority of the stations on the mainstem of the Yellowstone
plot above the mean line, indicating that they occur in braided channels.
For Reach 4, however, bedrock in the channel bank and bed and the incised
channel preclude development of characteristic irregular lateral channel
activity with the shifting main channel. Also of interest is the proximity
of several of the points to the mean line, particularly in the Powder River
Basin. This could indicate that, with a change in either bankfull discharge
or channel slope, a change in channel form would result, subject to any
local constraints such as in reach 4.
CHANNEL PROCESSES
The most significant characteristic of the Yellowstone River is its split
channel due to the'presence of many gravel bars and islands. The processes
by which these bars and islands evolved are discussed below.
The formation process of a midchannel bar has not been finally established;
however, several factors in the process have been identified (Leopold et al.
1964). It appears that, for a channel with coarse bed material, midchannel
bars can be formed by the selective deposition of the coarser fraction of the
bed load. This process implies several conditions necessary for braiding:
38
l
Q)
c.
0
CJ)
Q)
c c
0
~ u
.01
.001
100
Station
1 Yellowstone River at Livingston
2 Yellowstone River at Billings
3 Yellowstone River at Myers
4 Yellowstone River at ~1iles City
5 Yellowstone River at Terry
6 Yellowstone River at Inta~e
7 Yellowstone River near Sidney
8 Bighorn River at St. Xavier
9 Bighorn River at Bighorn
10 Tongue River at r-~il es City
11 Powder River at Moorhead
12 Powder River near Locate
Bankfull Dischargea
( cfs)
18,200
34,GOO
45,000
47,000
51,000
52,000
52,800
11,800
12,700
3,080
5,400
6 '80')
a estimated ~Y the 1.5-year-frequency flood
Braided
Meandering
1000 10,000
Bankfull Discharge (cfs)
Slope
.0024
.0014
.0005R
.0.0067
.(10058
.00046
.00025
.0020
.0016
.0019
.0014
.0011
Figure 12. Relationship of rivers in the Yellowstone Basin to the
general relation for channel form presented by Leopold and Wolman (1957).
100,000
1)
2)
3)
Sediment transport, in particular of the bed material, is required,
since bar formation is a depositional process. Heterogeneity of bed
material contributes to the deposition of the coarse fraction of the
bed material to begin the process, and once deposited, greater
velocity is required to reestablish motion. The initial deposition
then serves as a nucleus for further building.
Erodible channel banks are also necessary so that hydraulic capacity
lost through formation of the bar will be provided by erosion of the
banks.
Finally, rapid stage fluctuation has been shown to contribute to the
formation of channel bars through added bank erosion and fluctuating
transport capacity.
The change in channel morphology accompanying these processes tends to
increase the bedload transport capacity in the reach and provide equilibrium
(Simons et al .. 1975).
In addition to formation of midchannel bars as described above, there are
instances of midchannel bar formation by cutoff of a point bar in the more
sinuous reaches, such as reaches 3 and 4. In this situation, the main flow
of the river short-circuits the meander bend during high flow, eroding a
path across the point bar. If the cut produced is deep enough, a perennial
channel results, turning the point bar into a midchannel bar ..
Many midchannel bars progress toward the formation of a stable island,
requiring that vegetation become established on the bar. From field observa-
tion, it appears that deposition of sand on the leeward side of the island
is required for establishing vegetation. When this has occurred, a period
of several years without flows high enough to wash away the vegetation is
necessary. Vegetation aids in island building by increasing flow resistance,
causing deposition of fine material on the island. The growth of the island
is tailward: the material composing the island grades from coarse at the head
of the island to fine at the tail because flow velocity decreases through the
vegetation and progressively finer particles are allowed to settle. This
process often continues until the elevation of the island reaches the elevation
of the flood plain.
The hydraulic characteristics of a split channel are also different from
a single channel. In general, a split-channel reach is characterized by a
steeper slope. Flow resistance is higher also, and therefore, velocities are
generally less through a split channel than a single channel. In addition, the
depths in a split section are generally less and the total width of the water
surface greater.
Based on this analysis of the important channel processes in the system,
the governing hydrologic processes can be identified. It is obvious that the
annual high flows are a necessary part of the channel-forming process. These
flows trigger bed movement, new channel cutting, erosion, and cutoffs, and it
is movement of the bed and bank material and subsequent deposition which forms
the michannel bars or cutoffs and subsequently the islands. It is these flows
also that are capable of covering the already established bars with finer
material in order to establish an island.
40
The high flows can occur from two sources; (J) the annua 1 snowmelt cycle
and (2) the less-predictable ice jam and break. The ftrst of these high-flow
producers is typifi_ed by a relatively gradual rise in the late spring and a
sustained period of high flows. Velocity varies gradually with no sudden
changes. The tee jam and break phenomenon, on the other hand, is a sudden
local processcharacterized by rapid fluctuati_ons in stage, velocity, and
sediment transport regime. Because this is a local process, the effects are
also normally local' consisting of n) possible bed scour as water is sluiced
under the ice jam and (2) some erosion scars in vegetated areas caused by
rafting of large pieces of ice into channel banks and islands. Although this
process may prevent or interrupt the establishing of vegetation locally, it
is not likely to have a great impact on channel morphology. The spring runoff
event affects the entt~e system and, in addition to high discharges, has the
long duration necessary for the initation and continuation of such geomorphic
processes as the inundation of backwater areas, retarding encroachment of
vegetation.
The effects of the spring rundff in the formation and maintenance of
channel pattern cannot be overemphasized. These high flows provide the
dominant discharge--that flow which, through a co~bination of magnitude and
frequency of occurrence, has the greatest impact on channel form. This
discharge is identified by some to be the bankfull discharge (1.5-year
recurrence) and by others to be the mean annual flood (2-year recurrence). As
shown in the section on sediment transport (figures 32 and 33), flows of this
magnitude move the greatest amount of material.
In addition to sediment transport capability, high spring flows also
contribute to the channel form through flooding of abandoned channels, thereby
keeping backwater areas open and preventing the encroachment of vegetation.
Without the high discharges associated with the spring runoff, the building
of midchannel bars through sediment deposition or cutoff of point bars would
be diminished, and the backwater areas would eventually be filled by vege-
tation and sediment, thus becoming part of the flood plain.
In addition to the natural channel processes at work in the Yellowstone
River Basin, man has had an impact, if only a small one, on the geomorphic
character of the river. This impact has mostly been in the form of artificial
alteration of the river and riparian areas and in alteration of controlling
processes by development of the watershed. Riprapping, closing of side
channels, and clearing of bank vegetation have been ~he major alterations 6f
the river itself, with riprap far outweighing the other two. The effect of
riprapping is, in many cases, to stabilize the bank and stop ongoing erosion.
Bank clearing, on the other hand, promotes bank erosion by loss of the root
system which aids in binding soil material together. Riprap is common along
the river where railroads, highways, bridges, pumping plants, and any other
structures approach the river bank.
Changes in watershed. processes through changing land use and development
have also occurred. In particular, increased agriculture (both farming and
grazing) and timber cutting have probably increased sediment and water volumes
delivered to the river, thereby slightly offsetting the impact of past water
development. Data on these uses are not readily available, but the impact
has probably been small.
41
Channel process.es can be radically altered by tmpoundment of r vers. The
effects of construction of Yellowtail Dam on the Bi.ghorn Ri,ver is d scussed
above, on pages: 32 to 37 ; resultant geomorphic. cha,nges in the rtver are
summarized in tables 3, 4 and 5.
42
Because river processes are a function of a basin's yield of water and
sediment, this study i'ncluded a revi'ew of the climate, streamflow characteristics,
and hydraulic geometry of the Yellowstone Basfn,
CLIMATE
Elevations in the basin range from over 12,000 feet (3660 m) in the
Absaroka, Beartooth, Wind River, and Bighorn ranges to less than 2000 feet
(610 m) at the confluence of the Yellowstone and Missouri rivers. This
elevation difference results in great climatic variations from the alpine areas
of the high mountains to the semiarid plains of the eastern part of the basin.·
In the plans areas, precipitation averages less than 15 inches (38 em) per
year and consists mainly of rainfall occurring from April through September
with the greatest amounts·falling in May, June, and July. In the mountainous
areas, most precipitation occurs as snow during the late winter and spring months
and can average up to 80 inches (200 em) per year. Average annual precipitation
for the area is shown in figure 13. Large annual deviations from these averages
are common throughout the basin, particularly in the plains: As a result of.
these variations, large fluctuations in streamflow, particularly in the eastern
prairie streams, have occurred. Potential evaporation averages approximately
30 inches(760 em) during the growing season of May through September in the
plains.
STREAMFLOW CHARACTERISTICS
Table 7 presents some of the streamflow characteristics for the mainstem
Yellowstone River and its major tributaries. Table 7 shows that, as is most
often the case, unit runoff decreases downstream along the mainstem. Further,
it can be seen that the contribution of the tributary basins decreases down-
stream, reflecting the physiographic and concomitant climatic changes of the
tributary basins. There are mountain areas which contribute large amounts of
runoff in the upper Bighorn River watershed while there are almost no mountains
in the Powder River watershed. A comparison over the period of record indicates
that no great variation exists in flood peaks in the lower basin; that is, no
catastrophic floods have occurred in the period of record along the mainstem.
According to Stevens et al. (1975), if the ratio of the peak flood to the mean
annual flood is small (less than 3), the river is likely to be in equilibrium.
If the ratio is large (greater than 10), it is likely that the river will
exhibit nonequilibrium form. It appears, then, that the streams of the lower
Yellowstone River Basin are in equilibrium.
Flow duration curves have been developed by the U.S. Geological Survey
(USGS) using mean daily flows for all the stations in the lower Yellowstone
River Basin with sufficient length of record. Selected percentiles for the
stations are shown in table 8. In addition, flood frequency curves were
developed for the same stations using a procedure described by Beard (1962)
43
TABLE 7. Streamflow Characteristics in the Yellowstone River Basin.
Mean Maximum Ratio of
Period Annual -Unit Bankfull Flood of Maximum
of Discharge Runoff Dischar}ea Record Flood to mean
Station Record (cfs) (cfs/mi 2) (cfs (cfs) Annual Flood
Yellowtone River
at Corwin Springs 68 3 '119 1.19 15,000 32,000 1.88
Yellowstone River
at Livingston 49 3,757 1. 06 18,200 36,300 1.77
Yellowstone River
at Billings 46 6,913 0.59 34,500 69,500 1. 76
Bighorn River
at Bighorn 29 3,903 0.17 12,200 26,200 1. 75
Tongue River at
Miles City 31 427 0.08 3,080 13,300 3.24
Yellowstone River
at Miles City 47 11,420 0.24 47,000 96,300 1.82
Powder River
near Locate 36 616 0.05 6,800 31 ,000 3.23
Yellowstone River
near Sidney 62 13,070 0.19 52,000 159,000 2.48
CONVERSIONS: 1 cfs = .0283 m31s3c
1 cfs/m2 = .0109 m /sec/km2
aBankfull discharge estimated by the 1.5-year frequency flood.
, and the Water Resources Council (1967). This procedure consists of fitting a
Log Pearson Type III to the annual peak flow series. This distribution is
represented by the relation
log Q = m + ks
where = Q = instantaneous annual peak discharge
m = the mean of the logs of the discharges
s = the standard devi~tton of the logs
k = a factor dependent on the skew coefficient and
recurrent interval
As suggested by Beard (1962), a skew coefficient of 0.0 was applied in all cases.
The ~esults of this analysis are shown in table 9.
44
YEllowsTONE RIVER BASIN
AvERAGE ANNuAl PRECipiTATION IN ThE
YEllowsTONE RIVER BASIN
~ Less than 10 Inches
c==J 10 to 14 Inches
I ) I 14 to 20 Inches
1··.· .. 1 20 to 30 Inches
More than 30 Inches
SOURCE: U. S. Deportment of Agriculture 1970
0 10 20 40 60 80 100 Miles ~UitU~~==~~------~1 ======~1 ------c' ====~I
0 10 20 40 60 80 100 Kilometers
~~~~---t'==~~--.J'==~I
! MUSSELSHELL
WHEATLAND . \
I GOLDEN -= --T~ _j~V_AL L ~2--·
L_ 11 __.,.~
YELLOWSTONE
NATIONAL PARK
\
)
I
(
N YELLOWSTONE
RIVER BASIN
GARFIELD
WYOMING
McCONE
I
I
(
LT ~J----~·.·······.·· .. A
' _,
TABLE 8. Data from flow duration curves for the Lower Yellowstone River
Basin (cfs)
Percentage of Time Flow is Equalled or Exceeded
Station 1 10 20 50 80 90 99
YELLOWSTONE RIVER
at Corwin Springs 17,250 8,500 4,700 1,400 880 780 530
near Livingston 20,500 9,800 5,100 1 ,900 1 ,300 1 '1 00 860
at Billings 40,000 17,000 8,800 3,700 2,500 2 '1 00 1,350
at Mi 1 es City 56,000 26,000 14,500 7,200 4,700 3,700 2,100
near Sidney 65,000 28,000 17,000 8,000 5,000 3,900 1,600
BIGHORN RIVER -near St. Xavier 17,000 6,200 4,600 2,700 1,750 1 ,400 540
at Bighorn 18,000 6,900 5,200 3,400 2 '1 00 1,400 790
LITTLE BIGHORN RIVER
at Pass Creek 1,220 440 240 130 96 78 42
at Hardin 1,950 680 340 160 105 70 9.2
TONGUE RIVER
at the state line 3,500 1,200 650 260 200 160 2.5
below Tongue
River Dam 3,000 1 ,000 560 250 150 110 31
at Miles City 3,150 1 ,000 550 220 110 54 0
POWDER RIVER
at Moorhead 3,300 1 '100 550 210 84 41 1.8
near Locate 6,000 1 ,400 760 220 70 28 1.4
LITTLE POWDER RIVER
near Broadus 5,300 550 240 56 19 12 0
CONVERSIONS: 1 cfs = .02B3 m3;sec
In addition to mean flows, flow duration, and flood frequencies, the
seasonal variation of streamflow in the basin is also of interest. Figure 14
shows the average monthly flows for the Yellowstone River at several stations
47
along the mainstem. These distributions show that the peak flow occurs in June
and decreases rapidly in July and August. The effect of the physiographic and
climatic differences in the basin can also be seen in this figure. For instance~
the data for the stations at Miles City and Sidney show an early peak in the
month of March not present in the upstream-from-Billings data. This early
increase in flow is the result of the early melting 6f snow on the prairie
located mostly in the eastern part of the basin.
TABLE 9. Flood frequencies for the Lower Yellowstone River Basin (cfs)
Recurrence Interval in Years
Station 1.01 1.11 1. 25 1.5 2 5 10
YELLOWSTONE RIVER
at Corwin Springs 8,600 11 '700 13 '143 15,000 16,943 21,842 24,500
at Livingston 11 ,000 14,600 16,400 18,200 20,400 25,300 28,500
at Billings 19,500 26,800 30,600 34,500 39,400 50,900 58,000
at Miles City 26,500 36,000 41 ,300 47,000 53' 100 68,300 78,000
at Sidney 22,000 35,500 43,200 52,000 63,400 93,100 113,700
TONGUE RIVER
at state line 1,370 2,200 2,670 3,200 3,890 5,670 6,800
at dam 450 920 1 ,250 1,620 2,200 3,870 5,200
at Miles City 880 1 '750 2,360 3,080 4 '1 00 7 '140 9,500
POWDER RIVER
at Arvada 514 1 '120 1 ,513 6,000 8,490 5 '153 7,100
at Moorhead 1,730 3,250 4,220 5,400 7,060 11 ,800 15,400
at Broadu-s 319 562 714 900 1 '126 1 ,779 2,258
at Locate 1 ,560 3,550 4,980 6,800 9,590 18,500 26,000
BIGHORN RIVER
at Bighorn 5,350 8,430 10,200 12,200 14,700 21,200 25,700
at St. Xavier 4,000 7,300 9,300 11 ,800 15,000 24,200 31,500
at Hardin 567 1,040 1 ,340 1,700 2,190 3,570 4,600
LITTLE BIGHORN RIVER
at Pass Creek 390 668 835 1,030 1,290 2,000 2,500
CONVERSIONS: lcfs = .02832 m3/sec
48
25
28,000
32,000
65,000
90,000
140,800
8,400
7' 100
13,000
9,900
20,200
2,912
37,500
31,500
41,000
6,000
3,200
2,000,000 -
-1,500,000 -0
3:
0 -1,000,000 -E
0
G) ... ... 500,000 -fJ)
0 J
S I A I M I J l J I A
Yellowstone River at Billings
2,500,000 -
2,000,000 --0
3:
1,500,000 -
0 -E
0 1,000,000 G) -... -fJ)
500,000 -
!
0 0 N D J F M A M J I J A s
Yellowstone River at Miles City
2,500,000 -
2,000,000 --0
3:
1,500,000 -
0 -E 1,000,000 0
G) -... ...
fJ)
500,000
••••••••••••••••••••
:?:t;···
0 0 N D J I F M A M J T J r A s
Yellowstone River near Sidney
Figure 14. Mean monthly flows of the Yellowstone River mainstem at
three stations.
""
EFFECTS OF EXISTING WATER DEVELOPMENT AND USE
Historically, water use in the basin has been mostly for irrigation with
some municipal, industrial, and other agricultural uses. Since irrigation has
been by far the major water use, depletion has been mostly during the growing
season from April through October (table 10). Not all of the water diverted
for irrigation is consumed. A portion returns to the stream. The annual dis-
tribution of return flow is shown in table 10. Industrial uses tend to be
relatively constant throughout the year; municipal uses increase in summer.
TABLE 10. Monthly distribution of irrigation water withdrawals and return flow.
Month
0
N
D
J
F
M
A
M
J
J
A s
ausDI 1963
Percentage of Yearly
Irrigation Water Use
1
0
0
0
0
0
1
13
17
32
25
11
Percentage of
Return Fl owa
8
5
4
3
2
3
4
ll
14
18
18
10
Accompanying an increase in water use over time has been a steady develop-
ment of structural facilities in the basin in an attempt to temper the annual
fluctuation in streamflow and provide a more stable water supply. For the most
part, structural development in the form of on-stream storage facilities has
been confined to the Bighorn River Basin, where three reservoirs--Buffalo
Bill on the Shoshone River, Boysen on the Wind River, and Bighorn (Yellowtail)
on the Bighorn River--almost completely regulate the streamflow; about 86 per-
cent of the drainage area in the Bighorn Basin is above Yellowtail Dam. Other
regulation includes the Tongue River Reservoir on the Tongue River and Cooney
Reservoir in the Clarks Fork Basin. The total area of the Yellowstone River
Basin controlled by reservoirs is approximately 31 percent; the average annual
flow from this area is approximately 31 percent of the average for the basin.
In addition to impoundments, diversion structures for irrigation are located
along the river, the largest at Intake where a canal with a capacity of approxi-
mately 1200 cfs (34 m3/sec) diverts water for irrigation on the west side of
the valley. This diversion, like several others in the Yellowstone Basin, has
a diversion dam just below the headgate to provide the necessary elevation for
diversion even during low flows.
Present water use patterns and development structures have little effect
on streamflows in the winter months because water use during that period is
restricted to municipal and industrial uses and because the water supply is
50
slightly augmented by irri.gation return flows. During the April-to-October
irrigation season, however, an esti.mated 1.5 ·million af i.s consumed for
tr~tgation (Montana DNRC 1977). The portion of that total diverted during
June has only a minor impact on that month's high flows; less than 10 percent
of the total monthly discharge is diverted, and a significantly smaller
percentage of daily or instantaneous peak flows, It is apparent that past
water u~e has had a small impact on the flood discharges in the basin. The
greatest impact has occurred in the late summer when low river flows are
coupled with high demand for irrigation water.
Regulation by storage reservoirs has also affected peak flows. Although
the reservoirs do not generally change the mean annual flow greatly, their
main function is to decrease the annual variation in flows by storing peak
discharges for release during periods of low flow. This scheme has been in
operation in the Bighorn River Subbasin, and the floods of recent years have
been reduced accordingly. Yellowtail Dam has been operating only since 1965,
and the impact of its regulation has probably not yet been felt on the
Yellowstone mainstem.
HYDRAULIC GEOMETRY
Leopold and Maddock (1953) presented a method for quantitatively describing
the cross-section geometry and hydraulic characteristics of river systems which
has been successfully applied and expanded upon by others (Stall and Fok 1968,
Stall and Yang 1970, Emmett 1972 and 1975). The premise of the method is that
certain physical streamflow characteristics, e.g. top width (W), average
depth (D), and average velocity (V), are related to discharge (Q) by the
relations
W = aQb
D = cQf
V = kQm
(1)
(2)
(3)
where a, b, c, f, k, and mare statistically determined constants. Combining
equations (1) and (2) provides a relationship between cross-sectional area (a)
and flow:
A = (a·c) qb+f (4)
Each of these equations produces a straight line when plotted on log-log paper.
The validity of any relation presented using this format is easily tested
by applying the relation
W·D·V = Q (5)
Substituting equations (1), (2), and (3) into (5) gives
a·C·k = 1
if -b -ff.-+m = 1
which are necessary for the validity of the theory.
51
(6)
(7)
Equations (1), (2), and (_3), called hydraulic geometry by Leopold and
Maddock, can be applied either at-a-station (at a particular point alan~ a
stream) or i.n the downstream direction. Downstream (_constant-frequency)
hydraulic geometry· is accomplished by applying the relationships at several
points along a stream system fora constant frequency of discharge. For
example, at several points where adequate streamflow data are available
in a watershed, W~ D, and V are plotted against that Q which is equalled or
exceeded 10 percent of the time at each poi~t. In order to establish the
constant-frequency hydraulic geometry, then, continuous streamflow data
are necessary at each of the downstream locations.
An analysis of hydraulic geometry in the mi_.ddle and lower Yellowstone
River Basin wa~ undertaken. Since the only points in the basin where the
necessary cross-sectional and flow data were available were the USGS and DNRC
gaging stations, the analysis was based on these stations.
AT-A-STATION HYDRAULIC GEOMETRY
At-a~station hydraulic geometry relationships were calculated by simple
linear regression for all stations shown in figure 15. A sample graph of
the relationships for a single station is shown in figure 16. The b, f, and
m exponents in equations (1), (2) and (3) represent the slope of the relations
on a log-log plot and, therefore, show the rates of increase of W, D, and V,
respectively, with Q. A flat curve shows a small rate of increase; a steep
curve indicates a sharp increase. Even though the coefficients have little
physical meaning, they are necessary to reconstruct the equation and are
therefore presented along with the exponents in table 11. As can be seen
in that table, there are considerable variations in the b, f, and m values.
Table 12 compares the coefficients and exponents obtained for the Yellowstone
River Basin with data derived for other areas of the country.
CONSTANT-FREQUENCY HYDRAULIC GEOMETRY
An increase of streamflow in the downstream direction is assumed in most
parts of the country; however, this is not always true in Montana. In many
streams, particularly in the Yellowstone•s major tributary basins, depletion
for irrigation and natural causes give a stable or, at times, decreasing
flow in the downstream direction. For the flows (such as bankfull discharge)
most often used in a constant-frequency analysis this is not the case, however.
An analysis of the hydraulic geometry based on the 1.5-year flood, which is
claimed by mani i .::searchers (Leopold et al. 1964, Emmett 1975) to be the
frequency of the bankfull flow, was conducted for the lower Yellowstone River
Basin. The constant-frequency hydraulic geometry for the lower Yellowstone
Basin is shown in figures 17 and 18.
52
TABLE 11. Coefficients and exponents for at-a-station hydraulic geometry,
Yellowstone River Basin
W=aQb D=cQf V=kQm
Stationa a b c f k m
1 100.4 . 105 .23 .36 .043 . 53
2 105.3 . 12 . 15 .39 .06 .50
3 161.4 .075 .97 .25 . 01 .66
4 9.98 . 18 . 15 .6 . 71 . 19
5 43.95 .18 .75 .25 .03 .56
6 41.3 .07 .05 .61 .47 .32
7 21.3 .22 ; 18 .39 . 56 .28
8 3.02 .53 .23 .38 .7 .09
9 133.01 .07 .50 .30 .03 .54
10 3.08 .33 .56 .28 .58 .38
11 5.7 .37 .25 .33 .71 .29
12 99.3 .05 .08 .50 . 10 .49
13 37.3 . 16 . 17 . 41 . 16 .44
14 4.9 .36 .69 .20 .29 .44
15 61.9 .12 .03 .60 .49 .28
16 5.1 .33 .25 .46 .79 . 21
17 100.4 .11 .23 .36 .04 .53
18 51.7 . 13 . 15 .43 . 12 .44
19 139.8 .02 .07 .50 . 10 .48
20 4.8 .50 .35 .25 .58 .26
21 41.7 .18 .09 .50 .25 .33
22 159.7 .14 . 10 .43 .06 .43
23 7.06 .35 . 19 .42 .76 .21
24 20.1 .25 .11 .45 .45 .30
25 38.0 . 12 .28 .33 .09 .54
26 13.2 .39 . 12 .38 .27 .35
27 9.7 .33 . 16 .39 .63 .26
28 4.6 .44 .32 .33 .64 .22
29 9.8 .33 . 16 .39 .63 .26
30 18.9 .38 . 12 .40 .32 .32
31 192. . 12 .21 .39 .03 .49
asee figure 15
53
Hap Station
:-lumber Uumber
1 06191500
2 06192500
3 06214500
4 06217750
5 06287000
6 06290500
7 06294000
() 06294690. u
9 06294700
10 06294940
11 06294995
12 06306300
13 06307500
14 06307600
15a 42C02000
16 06307740
17 06307800
18 06307830
19a 42C07000
20 06308400
21 06308501
22 06309000
23 06309075
24 06317000
25 06324000
26 06324500
27 06324970
28 06325500
29 06326300
30 06326500
31 06329500
a DtiRC stations
Station Name
Yellowstone River at Corv-lin Springs
. Yellm'>lstone River near Livingston
Yello\'rstone River at Billings
Fly Creek at Pompey's Pillar
Bighorn River near St. Xavier
Little Bi~horn River below Pass Creek near Wyola
Little Biqhorn River near Hardin
Tullock Creek near Bighorn
Bighorn River at Biqhorn
Sarpy Creek near Hysham
Armells Creek near Forsyth
Tongue River at State line near Decker
Tongue River at Tongue River Dam
Hangin~ Homan Creek near Birney
Tongue River below Birney
Otter Creek at Ashland
Tongue River near Ashland
Tongue River below Brandenburg Bridge near Ashland
Tongue River at SH Ranch
Pumpkin Creek near t·1iles City
Tongue River at ~~iles City
Yellowstone River at ~1iles City
Sunday Creek near Mi 1 es Ci ty
Powder River at Arvada, Wyoming
Clear Creek at Arvada, Hyoming
Powder River at Moorhead
Little Pm>~der River above Dry Creek near Weston, Wyo.
Little Powder River near Broadus
Mizpah Creek near Mizpah
Powder River near Locate
Yellowstone River near Sidney
54
YEllOWSTONE RIVER BASIN
GAGING STATIONs IN ThE YEllowsTONE
RIVER BAsiN, MoNTANA
See legend on facing page.
0 10 20 40 60 80 100 Miles u-u-u I I I I I
0 10 20 40 60 80 100 Kilometers ~ I I I I
! MUSSELSHELL
GOLDEN\
I
WHEATLAND I
I
-------~-J VALLEY
I ,--------~-
L_ '--"'
CARBON
CORWIN SPRINGS
--~--::;-_--= =--r+-\---'--
Y E L L 0 W S T 0 N E ')
NATIONAL PARK (
N YELLOWSTONE
RIVER BASIN
GARFIELD
WYOMING
McCONE
PRAIRIE
INTAKE
DAWSON
J
15
'
J
}
j
~\ .,
~ ,.,
:•!
RIVER BASIN GAGING STATIONs IN diE YEllowsTONE
RIVER BASIN, MONTANA
See legend on facing page.
0 10 20 40 60 80 100 Miles
u-w-=is t--:i. t-:j
~ 40 60 80 100 Kilometers t j. t j
N YELLOWSTONE
RIVER BASIN
GARFIELD
I MUSSELSHELL I
GOLDEN\
WHEATLAND /
I -----r _J VAL L E Y I
I ,......__ - ---r----L -. _ __,_. -"-t-""'-
I
_J
I CARBON
-, _j
__ .._.. __________ _
WYOMING
McCONE
I
r
INTAKE
DAWSON
I
-I
I
I
---1 ...
1
J
J
" ---~-WIBAux
I
·FIGURE
I --1
,,
(
-+--
---
.J: -a.
Q)
c
(..)
Q)
1/)
........ --
-(..)
0
Q)
>
1000
10
10
100
100
100
w = 41.7 Q.l8
1000
Discharge (cfs)
D = .09 o.5o
1000
Discharge (cfs)
v = .25 o·33
1000
Discharge (cfs)
10,000
10,000
10,000
Figure 16. At-a-station hydraulic geometry for the Tongue River at Miles City.
TABLE 12. Comparison of at-a-station hydraulic. geometry exponents for the
Yellowstone Basin with other published values
River Basin
Bighorn River Basin
Tongue River Basin
Powder River Basin
Mainstem Yellowstone River
Average for Midwestern
United Statesa
Ephemeral Streams in the
semiarid United Statesb
Average of 158 gaging
stations in the u.s.b
Some Alaska Streamsc
Upper Salmon Riverd
aleopold and Maddock (1953)
bleopold et al. (1964)
cErranett (1972)
dEmmett (1975)
Average At-a-Station Exponents
b f m
. 21 .39 .36
.20 .42 .39
. 32 .38 .32
.11 .36 .52
.26 .40 .34
.29 .36 .34
. 12 .45 .43
. 19 . .39 .42
. 14 .40 .46
58
---
m
3:
~ -'t:J
~
:::J --"" c:
0 m
---
m c
.s::. -a.
Q)
0
Q)
C>
0 ._
Q)
>
<(
:::J -~ c:
0 m
1000
100
10
I
1000
w8 = 2.91 a8 .4 92
* * *
*
• •
Ds = 0.22 Os·367
•
•
•
10,000 100,000
. Bankfull Discharge Os (cfs)
Figure 17. Lower Yellowstone River Basin constant-frequency. hydraulic geometry: w8 and DB
59
10,000 *
C\1 --
m
<(
0
Q) ...
<(
3:
0
IJ..
:::1 -.....:: c:
0 m
(.)
Q)
1/)
....... --
m >
-(.)
0
Q) >
Q)
01
0 ...
Q)
>
<(
:::1 -.....:: c:
0 m
Ae = o.s5 aeo.a5a
1000
*
200
10 ve = 1.31 aeo.t5a
•
I ~-------r---,---r~~~-r~------~~--~~~~~~~~------~--~
1000 10,000 100,000
Bankfull Discharge Oe (cfs)
Figure 18. Lower Yellowstone River Basin constant-frequency hydraulic
geometry: AB and VB
60
DIMENSIONLESS HYDRAULIC GEOMETRY
An outgrowth of the constant~frequency analysis is the dimensionless
rating curves given by these equations (where B denotes bankfull):
~B = (~)b
gB = (~B) f
~ = (~B)m
~B = (~B) h+f
( 8)
{9)
(10)
( 11)
When flow duration and flood frequencies are attached to these curves, the
result is useful in estimating channel characteristics or flow rates. The
rating curves developed for the mainstem Yellowstone River, Bighorn River,
Tongue River, and Powder River basins are presented in figures 19 through 22.
Each of these rating curves may be used to estimate channel characteristics
for a similar stretch of channel. Because USGS gaging station data were
used, the curves should be used only for relatively straight stretches above
relatively stable flow controls. Flow rates determined from these relations
can be assumed. constant through a reach of river, providing there is no
significant inflow or diversion in the reach.
61
...
G)
~
E c ... c
Q.
::1 .... ....
c: c m
2 ...
G) -G)
E
~ c
Q.
0
.2
0 a:: .I
.01
...
:!
G)
E c ... c
Q.
:; .... ....
c: c m
2 ...
:!
G)
E
~ c
Q.
....
0
.2
0 a:: .I
.01
Recurrence Interval in Years
1.01 1.25· 2 10
1.11 1.5
_.-.-.~; ..... -· .··· ..... __ ,. ..... ··,.,.. ...... -· .·· /
345 .-· .........
D; = (Q/. )· -·-.•. •· _,. De ae -· .. ··· _,./ -·-· .. ·· .......... .·· ..... .. ·· , .....
A/ : ( Q/. ).442 ..•• •····· _,.,.,.. V/ : (Q/. ).495
Ae ae ·· ,.,..,.,.. Ve ae ,""
Duration in Percentage of Time
99 90 80 50 20 10 I I
.I
Ratio of Discharge to Bankfull Discharge
5 25
Figure 19. Dimensionless rating curve of the Yellowstone mainstem.
Recurrence Interval in Years
1.01 1.25 2 10
1.11
~· ,.....,.~.··· --· .· _;::::.. . .. ·.··
-~· .· __ :--........ · .. ··
V;, : (Q;. ).344 ---· _,. .·• ve ae ___ ,. .. ---·-.·· --· -:..-· .. ·
D/ = (Q~ ).388 .. ·······
De ae .. ··· .
Duration in Percentage of Time
99 90 80 50 20 10
I
.I
Ratio of Discharge to Bankfull Discharge
1.5 5
Figure 20. Dimensionless rating curve of the Bighorn River.
62
25 ..
...
Q) -Q)
E c ... c a.
:::1 -.... c c
Ill
2 ...
Q)
~
E c ... c a. -0
0 -c a:: .I
...
.!!!
Q)
E c ... c a.
.;! .... c c
Ill
0 -...
.!!!
Q)
E
~ c a.
0
0
c a:: .I
Recurrence Interval in Years
1.01 1.25 2 10
1.11
..,. ..
~:·· .--.::r:· .. ....... .,. ..... ·
~· .. · --:::::· .. ·· .,..."""':'.,.· ... ··· -.-.··· .,.-::, .......... ··
-.,.. ..··· A/ -(OJ. ).582 ~ =(OJ. ).43 -/· .. ····· 'As-oa
va oa_--.-.. ··· -.-.· . --,/
1.5 5 25
-.---,/D;. =(~ ).46 .,. .,. Ds oa -99
.01
.01
Duration in Percentage of Time
ep ~ ~ IP
.I
Ratio of Discharge to Bankfull Discharge
Figure 21. Dimensionless rating curve of the Tongue River.
Recurrence Interval in Years
1.01 1.25 2 10 ..
. ·
I. II 1.5 5 ..... 25
.·
-·
D;Ds =(0;oa)·225 -.-·-· -· -·-. -· -· -· -· -· -· -· -· .·
.·
.·
Duration in Percentage of Time
eo
I 5.0 2.0 IP
.I
Ratio of Discharge to Bankfull Discharge
Figure 22. Dimensionless rating curve of the Powder River.
63
BED MATERIAL
The results of pebble counts of bed material taken on midchannel bars
within the portion of the river studied are presented in figure 23. Based on
the size classification given in table 13, the great majority of the surface
bed material is in the gravel size range. Bulk samples of the top one foot
(.31 m) of the bed material were also taken; the results of a sieve analysis
of these samples are presented in figure 24. It can be seen t.hat the per-
centage of sand in the bulk samples is considerably larger than in the surface
samples, a common situation in most gravel-bed rivers because the sand on
the surface of the bed is winnowed out, leaving an armoring layer. In addition
to the lack of sand. on the surface of the bed, the gravel particles are inter-
locked as shown in figure 25. This interlocking would tend to make movement
of the bed even more difficult, since this interlocking would first have to
be disrupted.
TABLE 13. Sediment Size Classification
Size
64mm and larger
2rron to 64rron
0.062rron to 2mm
0.004mm to 0.062mm
.00024mm to 0.004mm
Classification
cobbles
gravel
sand
silt
clay
In the lower reaches of the river, near and downstream from Sidney,
the bed material changes from gravel to predominantly sand. An analysis of
data on bed material at the Sidney station collected regularly by the USGS
shows that, except during the highest discharges, the bed material has a mean
diameter of near 0.250 rrrrn. Therefore, this section of river is more typical
of a sand-bed river than of the gravel bed observed in the upper reaches.
SEDIMENT TRANSPORT
The transport of sediment· in a river is the process by which the system
maintains an equilibrium among the material delivered to the channel via the
watershed, the makeup and form of the bed, and the discharge of water.
Sediment may be transported either in suspension (where the. turbulent forces
of the flow are sufficient to counteract the gravitational forces on the
particle) or as bedload (where the particles are moved by rolling, sliding,
and bouncing along the bed of the channel). Bedload has the greater
influence on channel form and characteristics. Unfortunately, less is known
about bedload in terms of mechanics of motion and relationships to other
hydraulic parameters.
65
~ !!.... ... u c
G
::0
D"
CD
~
CD
-~ 0
~
E
::0 u
100
80
60
40
20
• • ·-----.. ......................
----·-·-·--:tt Jl
l::t··················t1
:0:------n
:0:-·-·-·-:0:
Location (in downstream order)
~mile below the Custer Bridge
helow confluence of Yellowstone and Biqhorn rivers
below Rosebud Creek
9 miles upstream fror.1 ~1il e$ City
2 miles upstream from ~iles Citv
below confluence of Yellowston~ and Powder rivers
above TP.rry
belO\'l. Ir_1take
5 10
Particle Size (mm)
fl'
I
I
I
I
I
I
I
I
. I
: I
! ~
50
" .,"
100
d5o (mm)
21
38
33
19
23.5
18.5
20.5
22
Figure 23. Grain size distribution from surface pebble counts on the lower
Yellowstone River.
66
----·
·············
100
80
... cu c
lL
cu
ii
E 60 0
0"1 (/)
.........
.X
::I
CD -0
cu
CP 40 0 -c cu
<J ... cu a.
20
0
.I
Top 1'
Top 1'
Top 1'
of island below confluence of Po~ttder R. i ver
of midchannel bar
of midchannel bar
above Terry
below Intake
•.. ... ...
1.0 5
Particle Size (mm)
10
.... -"
Figure 24. Bed material bulk samples.
'/
dso
13 mm
16 mm
12 mm
50 100
0 Figure 25. Typical bed material for the Yellowstone River above Sidney.
SUSPENDED SEDIMENT
Data on suspended sediment have been collected at several stations in the
watershed; however, a continuous record has been collected in Montana only at
those stations presented in table 14. Figures 26 and 27 are the rating curves
of suspended sediment vs. discharge for the major sediment-producing areas in
the basin. Suspended sediment is made up of sand, silt, and clay material.
The latter two, classed as fine material, are a product of the watershed and
have little influence on the channel form or sediment transport. These fine
materials serve to slightly increase the velocity and density of the fluid,
thus decreasing particle fall velocity and, therefore, increasing the transport
of coarser sediment, particularly sand. Therefore, large increases in fine
material will lead to increases in transport of the coarser fraction. The
portion of sand transported as suspended load is related to discharge in
figure 28 for the Sidney station.
Development of onstream storage reservoirs in the basin has altered
suspended sediment transport. The long period of record for the Bighorn River
at Bighorn (26 years) allows the investigation of this alteration. Figure 29
68
TABLE 14. Suspended sediment data for the Yellowstone River Basin
Station
Bighorn River
· at Bighorn
Little Bighorn
River near
Hardin
Tongue River
below Branden-
burg Bridge
Tongue River at
Miles City
Yellowstone River
at Miles City
Powder River at
Moorhead
Powder River
near Locate
Yellowstone River
near Sidney
Period
of
Recorda
(years)
26
6
1
5
3
1
4
37
Sampling
Frequency
daily
daily
daily
daily
daily
daily
daily
daily
Average
Flowa
(acre-feet}
2,752,000
327,000
641,000
258,000
8,920,000
489,000
392,000
9,194,000
CONVERSIONS: 1 cfs = .028 ems
1 ton (short} = .91 metric ton
1 T/mi2/yr = .35 metric tons/km2/yr
Average
Suspended
Load
(T/yr}
5,123,585
396,273
267,828
568,000
16,580,000
5,763,551
6,032,000
25,051,000
Unit
Sediment
Produ2tion
(T/mi /yr}
224
306
66
105
344
713
468
260
aonly those years of record were included in this table for which sediment
records were available. For that reason, the periods of record are not as long
as they would have been for these stations if only flow records had been
sought, and the 11 average flow 11 column reads differently than it would have if
all years of flow record had been included.
69
10,000,000
1,000,000
>o
0
"0
........ ..... 100,000
"0
0
0
...J -c:
Q)
e.
"0
Q)
(/)
"0
Q)
"0 c: 10,000
Q)
0.
Ill
;::,
(/)
s = .oooool32 a2.40
1000
100
1000 10,000 100,000 1,000,000
Mean Daily Discharge (cfs)
Figure 26. Suspended sediment load vs. discharge: Yellowstone River near
Sidney.
70
1,000,000
100,000
-10,000
>.
0
"0
~
"0
0
0
_J -c:
Q) 1000 E
"0
Q)
(/)
s = .ooogs o2.282
"0
Q)
"0 c:
Q)
a.
(/)
::1
(/) 100
10
10 100 1000 10,000
Mean Doily Discharge (cfs)
Figure 27. Suspended sediment 1 oad vs. discharge: Powder River near
Locate.
->.
0
"'0
~
"'0
0
0
.....1
"'0 c
0
CJ)
"'0
Q)
"'0
1,000,000
100,000
10,000
; 1000
0. ,
::l
CJ)
100
10
s = .ooooo29J a2.2oa
1000 10,000 100,000 1,000,000
Mean Daily Discharge (cfs)
Figure 28. Suspended sand load vs. discharge: Yellowstone River near
Sidney.
shows the relationship over time of the total annual streamflow to the total
suspended sediment discharge. Although the closure of Boysen Dam seems to have
had little impact on the sediment yield of the basin, the completion of
Yellowtail Dam has affected the sediment yield sig~ificantly. From 1948 to
1965, the average runoff was 2,712,000 af (3340 hm ), and the average annual
suspended sediment production, 7,252,604 tons (6,579,562 metric tons). During
the 6 years that data were collected after Yellowtail construction, the
average annual runoff was 2,857,000 af (3520 hm3), similar to that of the
previous period, but the sediment in transport averaged only 1,515,990 tons
(1,375,306 metric tons) annually. This change in sediment transport due to
trapping most of the incoming sediment in the reservoir is also demonstrated
in figure 30, where successive suspended sediment rating curves for the Bighorn
station are shown. As can be seen in figure 30, the sediment production before
and after the closure of Boysen did not differ significantly. After the
closure of Yellowtail Dam, however, the relation was markedly altered, indicating
the loss of incoming sediment. In addition to the shifting in the curve, the
correlation between the sediment load and discharge decreased greatly,
indicating a decreased dependence of sediment discharge on streamflow.
A corresponding change in sediment transport on the mainstem of the
Yellowstone River, as reflected by records at the Sidney station, is not yet
apparent. A long record of daily suspended sediment data exists at the
Sidney station. Comparison of suspended sediment rating curves from periods
before and after the closure of Yellowtail Dam reveals no trend to a change
in slope, indicating that sediment previously in storage in the bed and banks
along the mainstem is being removed to accommodate the decreased sediment
inflows of the Bighorn River; prior to the closure of Yellowtail Dam, the
Bighorn River contributed from 27 to 38 percent of the sediment measured at
Sidney, but since the closure, the Bighorn River has produced only from 5 to 8
percent. At some future time, when a new equilibrium is reached along the
mainstem, a shift in the sediment rating curve at Sidney is likely.
BEDLOAD
As stated previously, little is known about the mechanics of bedload
transport, and no satisfactory method has yet been established that allows
prediction of this phenomenon with any degree of confidence. In fact, complete
agreement has not yet been reached on a technique for measuring bedload,
although the Helley-Smith sampler is now being used by individuals in the USGS
with apparently good results. The mechanics of bedload movement have been
described by Simons et al. (1975) as being sudden and erratic with the
particles sliding and rolling along the bed; periods of motion are followed
by periods of rest. The motion is variable across the channel and with time.
Based on this description, Simons et al. state that the statistical analysis of
a large number of samples is required in order to estimate the bedload
movement in a river. This character of bedload has also been documented by
Emmett (1976) for large, gravel-bed rivers where wide variability in bedload
transport under the same hydraulic conditions has been observed.
Even though bedload is not easily estimated, and in many cases is
10 percent or less of the total sediment load, bedload transport is the pro-
cess which has the greatest impact on morphology of the river. Several
73
4,000,000
3,500,000
:§. 3,000,000
~
0
'E g 2,500,000 ....
iii
0
::1
:§ 2,000,000
<l
1,500,000
.1,000,000 '0
Q)
fl)
0
(.)
E
0 c
c:
Q)
fl)
>.
0 m
,
/
/
\
\
\
\
\
\
' ' '
\
'
'0
Q)
fl)
0 u
E
0 c
0 -:.
0
~
16,000,000
14,000,000 -
f-
Gl
12,000,000 c> ....
0 s:. u ..
10,000,000 0 -c
Gl e
8,000,000 '0
Gl
(/)
'0
6,000,000 Gl
'0 c
Gl
Q. ..
:::J
4,000,000 (/)
0
:::J c
2,000,000 .q
Figure 29. Streamflow and suspended sediment discharges for the
Bighorn River at Bighorn.
74
100,000
->.
0 10,000 't:J
~
't:J
0
0
...J -c:
Q)
E
't:J
Q)
(/)
't:J
Q)
't:J c: 1000 Q)
Q.
(/)
::J
(/)
s=.ooo154 a2.224 ./
// s = .000409 0 2.103
:/
/!
:"/
/!
/!
/1
I
.I
/
I
I
I
I
I
I
I
f
I
{
s = .00111 aL736
/:"
1/
/.:
1/
10,000
Mean Doily Discharge (cfs)
1970
1958
1950
100,000
Figure 30. Suspended sediment rating curves for the Bighorn River
at Bighorn: 1950, 1958, and 1970.
75
investigators (Lane and Borland 1954, Schumm 1971) have attempted to estimate
bedload from such factors as suspended sediment concentration, bed and bank
material, channel geometry, and channel stability. Based on these criteria,
the bedload of the Yellowstone could be estimated to be less than 10 percent
of the total sediment load.
In hopes of more accurately establishing the relationship of streamflow
to bedload, samples were taken at several points along the mainstem of the
Yellowstone River using a Helley-Smith sampler with a 3-inch-square orifice
and a bag with 0.25-mm mesh. The adequacy of the sampling was, however,
subject to both the annual variability of streamflow and technical problems.
The streamflows during the 1976 spring runoff period were considerably less
than would be desirable for such sampling; the peak flows and corresponding·
flow frequency are given in table 15. In addition, the loss of a sampler prior
to the peak flow resulted in the loss of valuable data. Nonethless, some
samples were collected (table 16). Much of the bed material was not moved
due to the low peak flows, and sand made. up the bulk of the samples. The
wide variability of the samples can be seen in the data for the Sidney station,
where the bedload shows little relation to discharge. The situation in the
Yellowstone River in 1976 was much the same as that encountered by Emmett
(1976) on the Snake and Clearwater rivers in Idaho during a low spring runoff
event. Only sand and small gravels were in motion on the bed due to the
incompetence of the flows to move the larger fraction of the material.
TABLE 15. Maximum flows for the lower Yellowstone River Basin in 1976.
Gaging
Station
Sidney
Miles City
Billings
CONVERSIONS: 1 cfs = .02832 m3jsec
aMaximum mean daily discharge
Maximum Dischargea
for 1976 (cfs)
46,600
45,300
39,200
Flood Recurrence
Interval (year)
1.3
1.4
2.0
TABLE 16. Bedload data collected in 1976: Yellowstone River Basin at Sidney
Date
6/21/76
6/01/76
7/31/76
Discharge
(cfs)
29,000
27,300
25,000
Bedload Discharge
(T/day)
216
426
287
CONVERSIONS: 1 cfs = .0283 m3/sec
1 T/day (short) = .907 T/day (metric)
1 mm = .0394 in
76
Mean Particle
Size (mm)
0.62
0.30
0.27
I
Because the sampling data covered such a small range of the particle sizes
represented in the bed due to the small peak runoff, it was necessary to
estimate the relationship of streamflow to bedload from information available
in the literature and from existing data on bed material distribution along the
river. Initially, an estimate of that portion of the bed in motion at a given
discharge is enlightening because the flows at which the entire bed shoul~ be
in motion can be estimated. Leopold et al. (1964) presented a relationship
between shear stress and particle size. This relationship, which has been shown by
Emmett (1976) to be reasonably accurate when applied to bedload data, is based
on laboratory and field data. Using these data, figure 31 was developed for
the Miles City station, chosen because of the availability of hydraulic data
necessary for the analysis. The results must be considered site specific, or at
least applicable only to those points in the basin that have geometric and
bed material characteristics similar to the station being used. Also shown
on figure 31 is the percentage of the bed material in motion at a given dis-
charge and the frequency of occurrence of that discharge. These dat~ indicate
that a flood with a recurrence interval of once in two years is necessary to
initiate movement of the entire bed. However, because some sections of the
channel are deeper than the mean depth, particles larger than those indicated
on figure 31 could actually be transported.
According to an analysis presented by Vanoni (1971), several equations can
be applied to estimate bedload transport based on data used in development of
the relation, particularly sediment size and gradation. In selecting a formula
to use in estimating bedload, the character of the bed, the major criterion
separating the many different formulas available, must be considered. Also,
because the results obtained will still be only an estimate lacking supporting
data, a simple equation which has been proven in situations similar to those
found along the Yellowstone would be the best choice. Given these criteria,
the equation of Schoklitsch (Graf 1972, Vanoni 1971), which was developed
using both graded and ungraded sediments up to 5 mm in size, was chosen for
the river above Savage. This equation has been successfully applied to two
large gravel-bed rivers in Europe. In this reach of the Yellowstone, as
discussed previously, the bed material is also gravel. In the river above and
below Sidney, a simple rating curve of sand discharge vs. water discharge, pre-
viously presented as figure 28 will be used.
The form of the Schoklitsch equation, which incorporates the concept of a
critical shear necessary to initiate motion, is given below:
L 25.03 sYz ( ) qb = P·~ q-q . 1 d . Cl
Sl
d . q . = 0.0638 _jLL Cl • s~
where: q is the water discharge Rer foot of channel width
qci is the critical value of discharge for initiating movement
qb is the sediment transport rate
S is the slope of the stream
dsi is the mean diameter of the particle
P; is the fraction of bed material with mean size dsi
77
100
-E
E -c:
0 -0
::E
c:
~
)(
0
E
"0
Q) 10 N
CJ)
Q)
u -...
0 a..
.e
~
E
)(
0
::E
I
1000
99
I
Recurrence Interval in Years
1.05 1.5 5
1.25 2 10
Flow Frequency, Percentage of Time Equalled or Exceeded
90 80 50 25 10 5
I I I I I I
10,000
Discharge (cfs)
1.0 .5
I I
.01
I
100,000
Figure 31. Estimated relationship between discharge and particle
size moved for the Yellowstone River at Miles City.
78
Using discharges and channel geometry at the Miles City station and bed
material information for a midchannel bar approximately nine miles above Miles
City in a reach similar to the station, figure 32 was developed by applying the
Schoklitsch formula. This curve, although hypothetical, shows the rapid.
decrease in competence to carry bed material with a decrease in discharge,
indicating the presence of a point at which the bed is essentially still, with
only sand in motion over the larger bed material. However, it should be
remembered, as pointed out by Maddock (1976}, that the particle size of the
bed does not necessarily indicate the particle sizes of the sediment being
transported.
Although the rating curve of sediment transport vs. discharge is informa-
tive, it does not describe frequency of occurrence of a given discharge nor
the importance of a given discharge over the long term. Therefore, figures
33 and 34 were developed for the Yellowstone River at Miles City and 'at Sidney,
respectively. These figures indicate that the flood with the frequency of
occurrence of 1.5 years is the most effective discharge in bed sediment trans-
port in the Yellowstone Basin. The other available applicable formulas for
modeling sediment transport would have given similar results, since all employ
approximately the same form.
Figure 33 is based on the flow duration curve for the USGS gaging station
at Miles City and the hypothetical bedload rating curve presenting in figure 32.
Figure 34 is based on the flow duration curve and the suspended ~and load
collected at the USGS gaging station near Sidney.
79
10,000
'0
0
0
"0
Q)
CD
1000
100
1000 10,000 100,000
Discharge (cfs)
Figure 32. Schoklitsch bedload curve; Yellowstone River at
Miles City.
80
1,000,000
-~
"C
0
0
...J -c
Q)
E
"C
Q)
C/)
co
-~-------------------------------------------y--
70
60
Flood Recurrence Interval in Years
1.01 1.11 1.25 1.5 2 5
50
40
30
20
10
0 10,000 20,000 30,000 40,000 50,000 60,000 . 70,000 80,000
Discharge (cfs)
Figure 33. Sediment.duration curve showing most effective discharge: Yellowstone River at Miles City.
90,000
Flood Recurrence Interval in Years
1.01 1.11 1.25 1.5 2 5
10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000
Discharge (cfs)
Figure 34. Sediment duration curve showing most effective discharge: Yellowstone River at Sidney.
PROJECTIONS OF FUTURE USE
In order to adequately and uniformly assess the potential effects of
water withdrawals on the many aspects of the present study, it was necessary
to make projections of specific levels of future withdrawals. The methodology
by which this was done is explained in Report No. 1 in this series, in which
also the three projected levels of development, low, intermediate, and high,
are explained in more detail. Summarized in appendix A, these three future
levels of development were formulated for energy, irrigation, and municipal
water use. Annual water depletions associated with the future levels of
development were included in the projections. These projected depletions,
and the types of development projected, provide a basis for determining
the level of impact that would occur if these levels of development were
carried through.
IMPACT OF WATER DEVELOPMENT ON CHANNEL FORM AND PROCESSES
Development of water in the Yellowstone River Basin could take many forms,
and the geomorphic impact would depend on the type of development. In general,
as it pertains to geomorphic impact, development could be of two types;
onstream storage or diversion. Diversions can be further divided into pumps,
headgates, and headgates with a low diversion dam. The general impacts of
each of these types of development will be discussed, with particular
reference to their probable impact on the Yellowstone River.
IMPACTS OF ONSTREAM STORAGE
The geomorphic impacts of onstream storage reservoirs,which have been well
documented (Leopold et al. 1964), result from decreasing the dominant dis-
charge and sediment supply. Directly below a dam, the channel tends to be
degraded and/or widened until an equilibrium is reached between channel
erosion and stream energy. On the Yellowstone, this equilibrium would
probably take the form of armoring of the bed for some distance below the dam.
A change in channel form would also be likely due to decreases in discharge
and sediment. Figure 12 on page 39 illustrates that decreasing discharge
stimulates change toward a meandering channel. A similar change results from
decreasing sediment load. Further downstream from a dam, there would be a
possibility of aggradation along the mainstem at and below tributaries if
mainstem flows were decreased below the level competent to carry the sediment
load provided by the tributary streams. Considering the mainstem of the
Yellowstone, this aggradation could occur below the mouth of the Powder River,
given the large sediment load introduced by the Powder. In addition to
aggradation on the mainstem, aggradation could also occur along the lower
reaches of the tributaries as a result of the change in base level.
83
IMPACTS OF DIVERSION
Changes in channel form and sediment transport due to pumping or
diversion are not easily assessed because the impact on the system would not
be as great. In general, diversion decreases water discharge while the
sediment discharge is either not affected, as through pumping, or is
decreased only slightly. Decreases in sediment would seldom be equivalent
to decreases in streamflow. For direct diversion and pumping developments,
a change in channel form from braided to meandering could result if depletions
were of great enough magnitude. For a diversion with a small dam, effects
similar but much less pronounced than those noted below onstream storage
projects would be noted until the area behind the dam filled with sediment.
Sediment would then again be introduced to the channel and a slight reverse
effect might be expected.
Based on the geomorphic analysis of the five reaches of the Yellowstone
identified on pages 19 to 31 and on water use projected in appendix A, reaches
2 and 5 are the ones which could be affected most severely by water withdrawal.
As stated previously, Reach 2 is representative of the. Yellowstone River from
the mouth of the Bighorn River to Forsyth, exhibiting considerable braiding in
character; Reach 5 is representative of the river from Glendive to the mouth
with much the same character. Impacts can be expected in these reaches due
to a combination of the present form exhibited in these reaches and the pro-
jectgd decrease of discharge in them. Reach 1 should not be affected since
there is little increased depletion expected above the Bighorn River. Reach 3,
with less braiding and fewer islands than other reaches, should retain
essentially the same meandering form currently being exhibited. Reach 4
exhibits control of the channel form by bedrock and its incised nature.
In order to adequately assess the impact of the proposed development
schemes on the two sections of the river thought to be most likely to change,
estimates of the change in flow regime as a result of this development are
required. In considering channel morphology, changes in flow in the upper
range would be of the greatest interest. Table 17 estimates the impact of
development at Miles City and Sidney for the three possible levels of
agricultural and industrial development. In general, development impacts are
greater on middle and lower range flows than on high ranges; the major impact
on flooding would come from new reservoirs in the basin.
These data indicate relatively small changes (on the order of 5 percent)
in the dominant discharge, assumed to be bankfull stage. Referring to
figure 12 on page 39, it can be seen that changes of this magnitude would
result in no significant plotting position for the points in question, and,
therefore, changes in channel form would not be expected.
Because stage largely determines the areas inundated during high flows,
the relative impacts of these depletions on stage should be assessed. Based
on the high level of development for the Middle Yellowstone and the existing
stage-discharge relationship, a decrease in stage of approximately 0.2 ft ·
(.06 m) can be expected at Miles City as this discharge is decreased through
increased depletions. At Sidney a decrease of 0.4 ft (.12m) can be expected,
based on the depletions of the high development level in the Lower Yellowstone
and the existing stage~discharge relationship. Smaller decreases in stage
84
-can be expected for lower levels of development. Corresponding to this
stage decrease, presented in table 18 are estimates of changes in width, depth,
and velocity associated with the decreases in bankfull discharge presented
in table 17. These changes are based on the channel geometry relationships
at those stations. Changes for lower development levels would be smaller.
TABLE 17. Projected Percentages of Streamflow Depletions in the Yellowstone
River
Depletions (%)
Flow Category Discharge High Level Intermediate Low Level
(cfs) of Development Level of of Development
Development
AT MILES CITY
Five-year flood 68,000 5.2 3.7 3.2
Mean annual flood 54,000 6.5 4.6 4.1
1. 5-year flood 47,000 7.5 5.3 4.7
Mean annual flow 11 ,420 21.9 15.8 10.5
AT SIDNEY
Five-year flood 92,000 4.0 3.3 1.9
Mean annual flood 64,000 5.8 4.7 2.7
1.5-year flood 52,000 7.1 5.8 3.3
Mean annual flow 13,070 36.0 29.1 19.1
NOTE: The methodology by which these depletions were projected and the
details of the projections are given in Report No. 1 of this series and in
appendix A.
Finally, changes in the size of sediment and rate and volume of sediment
transport can be estimated from the projected effects of depletions on the
existing flow regime. The ability of the Yellowstone River to carry fine
sediments is likely to remain unchanged by flow depletions. The competence
of the river to carry coarse material will decrease only slightly at bank-
full discharge. Using the Miles City station as an example, the change in
bankfull discharge associated with the high level of development would amount
85
TABLE 18. Changes in width, depth, and velocity at bankfull discharge (.Q 1 5)
due to decreased flows projected for two Yellowstone River stations at the"
high development level.
Present Percentage Percentage Change at Q1 _5 in:
~1. 5) Change
Station cfs in Ql.5 Width Depth Velocity
Yellowstone'River
at Miles City 47,000 -7.5 -0.8 -3.0 -3.0
Yellowstone River
near Sidney 52,000 -7.1 -0.8 -2.7 -3.4
to a decrease in maximum particle size moved from 64 to 62 mm, approximately.
The change in bedload transport rates is more substantial due to the exponential
relation·between discharge and sediment transport. At bankfull discharge,
the transport of coarse material would be decreased by 10 percent due to the
depletion resulting from the high level of development. By changing the flow
duration curve, the depletions would decrease the capacity of the river to
transport sediment over the entire range of flows experienced; in other words,
streamflow depletions would reduce the area under the curve shown in
figures 33 and 34. These estimated losses in sediment transport capacity,
based on the change in area under the curves, are given in table 19.
TABLE 19. Projected losses in bed material transport capacity for two
stations on the Yellowstone River (%)
High Level Intermediate Level Low Level
of Development of Development of Development
Yellowstone River
near Miles City 28 21 17
Yellowstone River
near Sidney 26 21 1.2
These losses in volume of sediment transported over the long term could
have two results. First, as the volume of bed material transported is decreased,
the channel forms and patterns dependent on this process must change accordingly.
The state of the art does not now permit a quantitative estimate of this impact.
It can be said that, first, there is likely to be some long-term decrease in
island-forming. Second, since the capacity of the river ·to transport sediment
will be decreased, it is possible that the river will not be capable of trans-
porting the sediments delivered by the tributary basins, leading to aggradation
in reaches directly below the confluences. The likelihood of these impacts
is, however, not great when several facts are considered. First, the
86
long-term influence of Yellowtail Dam will be to decrease sediment loads in
the mainstem, tending to counteract decreases in discharge and prevent over-
loading problems. Second, it does not appear that any of the tributary
streams produce a great deal of coarse material, the common cause of aggradation
in channels. Finally, no onstream storage was considered for the mainstem in the
study area, implying that large variations in streamflow are still likely even
under the high development projection, since canals and pumps are not
effective in appreciably affecting peak runoff events. Therefore, the annual
scour of any fine material which has settled in pool and backwater areas
should continue. '
In addition to the mainstem, impacts would result on the major tributaries
as a result of increased development. In general, the Bighorn and Tongue river
basins, due to their high degrees of regulation and development, are unlikely
to be further affected. The Powder River, however, has been subject only to
minor individual development in the past, so that a large dam such as the one
proposed at Moorhead would significantly affect this river. A dam and
associated reservoir near the site of the one proposed for Moorhead would
trap 98 to 99 percent of all incoming sediment (Borland 1971). Due to the
highly erodable nature of the bed and banks of the river below the reservoir
site, it is likely that a great deal of bed and bank erosion would occur
along the entire river course, threatening existing diversion and pumping sites.
Finally, it should be noted that any attempt to decrease the impact of
diversions during the low-flow period through on-site storage would further
decrease peak discharges, thereby increasing the impact on the channel-forming
processes.
87
The Yellowstone River is under pressure from both agriculture and industry
as water requirements in eastern Montana increase. The impact of water develop-
ment, in particular of a decrease in discharge, on the morphology and sediment
transport of the river is the subject of this report. These changes, which
could affect the aquatic and terrestrial ecosystems, would result from changing
the flow regime of the river.
Presently the Yellowstone River exhibits the same form found by Captain
Clark in 1806--not that the river has not changed, since change is the
character of much of the Yellowstone, but the braided quality of the stream
has been maintained. It is this braided charatter, the most important geo-
morphic feature of the river, which creates the ecosystem that yields the
diversity and abundance of wildlife found along the river. The river sections
above Forsyth (RM 238, RKM 383) and below Glendive (RM 96, RKM 154) best
exhibit braided form and would be most susceptible to change with depletions of
flow.
In the past, water use has increased slowly along the Yellowstone, the
major demand being for irrigation. The impact on the bankfull discharge as a
result of this type of development has been smalL The sediment characteristics
in the basin havebeen recently altered through the construction of Yellowtail
Dam, which has decreased the sediment load of the Bighorn River as much as
80 percent.
The levels of depletions considered in this report were small for the
bankfull discharge; the relative impact was less for larger flows and
greater for lesser flows. The changes in stage resulting from these changes
in discharge would also be small, as would changes in width, depth, and
velocity. The impact of changes in flow regime on sediment transport would
be marked when the effect of this modification on total volume is considered.
Based· on the analysis of channel morphology and sediment transport in
the lower Yellowstone River Basin, the following specifi~ conclusions can be
drawn:
1) The estimated depletion levels will decrease the bankfull discharge
for the mainstem Yellowstone River from about 7.5 percent at a high
level of development to between 3 and 5 percent at the low level of
development. High flows will be decreased by lesser percentages
and lower flows by greater percentages.
2) The decrease in river stage caused by projected depletions would be
less than 0.2 ft for Miles City and 0.4 ft for Sidney at bankfull
conditions.
3) The impact of depletions on width, depth, and velocity would be
between 1 and 3 percent at bankfull discharge.
89
4) The impact of depletions on the transport of bed material is larger
than would be expected given the small changes in hydraulic variables.
Decreasing the discharge at all frequenci~s leads to maximum losses
of sediment transport of 28 percent at Miles City and 26 percent at
Sidney at a high level of development, which could result in a
decrease in channel activity, although aggradation in the main
channel is unlikely.
5) The impact of the depletions on channel form are a direct result of.
changes in streamflow and in the concomitant sediment transport.
The loss of bed-material transport would decrease channel activity
and tend toward a smaller channel with less midchannel bar formation.
Quantification of this is not possible.
In general, the impacts of the estimated depletion on the important
elements of channel form cannot be quantitatively assessed. A look at history
may shed some light on the change to be expected, however. The estimated
future depletion, though increased over historical depletion, is of the same
order of magnitude, and it appears that historical depletion has not appreciably
altered the channel form of the Yellowstone since Captain Clark. first
described it in 1806. It is likely, then, that future depletion, if confined
to diversion and pumping rather than onstream storage, will have a similarly
small impact.
90
by
Robert Curry
Mark Weber
91
PURPOSE
Due to the paucity of detailed data on the form and behavior of small
perennial and ephemeral streams in the northern Great Plains, there is no
reliable data base from which to analyze the geomorphic and hydrologic
impacts resulting from existing uses of the land to forecast the extent and
nature of the potential impacts resulting from proposed coal-related and
agricultural development in many of the watersheds of southeastern Montana.
The first objective of this research was to establish quantitative and
qualitative biophysical baseline data on the form and behavior of the
streams of the Montana portion of the Fort Union Basin. To do so, a
network of 22 Vigil monitoring sites was established during the summer of
1975. These Vigil monitoring sites, located on many of the nonglaciated,
headwater tributaries to the Yellowstone River, are permanent, bench-marked,
and recoverable.
SCOPE
An effort was made to include a broad sampling of stream channel type
and size, geomorphic setting, and prevailing land use in the sites selected
for inclusion in the Vigil Network. Of the sites surveyed, five are located
in first-order watersheds (Horton 1945), five in second-order watersheds,
five in third-order watersheds, and seven in fourth-order watersheds (see
figure 35). Information collected for each site includes surveyed channel
cross-sections, maps, transects of site vegetation, and photographs ..
STUDY AREA
Twenty-two detailed Vigil Network stations were established on tributaries
of the Yellowstone River (figure 35).
The relationship of the established Vigil sites to the generalized
bedrock geology of the region is illustrated in figure 36. Because the
perennial stream valleys of the region are floored by varying thicknesses
of alluvium, stream channels through these valleys possess potentially
mobile beds and banks. The ephemeral channels surveyed in this study,
surrounded by much smaller volumes of alluvium, are more constrained by the
local bedrock.
93
Site No. Strear1 nrainaqe Basin Area
MY-Viqil Site Location Order (km2)
21 Tributary to Hollowood Creeka 1 2
22 Tributary to Padlock Creeka 1 , ,_
6 West Fork. Tullock Creek 1 4 .• 5
5 · Vance Creeka 1 . 15
7 North Fork Rosebud 1 21
8 South Fork n.osehud 2 47
9 Rosebud at t·1i chael Ranch 2 69
18 Loqging Creek 2 7tl.5
3 Hest ForV. Huddy Creek 2 91
\.0 2 Rosebud Creek at Helvey Ranch 2 95 ~
4 East Fork Sarpy Creek 3 136.5
1tl Upper Owl Creek 3 170
15 Mid Owl Creek 1 181
12 Lower Owl Creek 3 221
13 Sarpy Creek at Colstrip Rridqe 3 52tl.5
1 Arme 11 s Creek tl 807
10 Lower Tullock Creek 4 1163
11 Lower Sarpy Creek 4 1165.5
19 Upper Pumpkin .Creek 4 1308.5
17 Upper Otter Creek 4 1516.5
20 Lower Pumpkin Creek 4 1790.5
16 Lower Otter Creek 4 1816.5
a Ephemeral stream
See legend on
facing page.
Base Map from USGS
Figure 35. Vigil network stations in southeastern Montana and the approximate boundaries of the watersheds monitored.
QTt
Tw
Tfu
Khc
Kh
Kjr
Kc
Kf
Kt
Ju
Ou
Terrace !)eposits
Wasatch Formation
Fort Union Formation
Hell Creek Formation
Bea rpa\'J Sha 1 e
Judith River Formation
Colorado Shale
Frontier Formation
Thermopolis Shale
::J-Quaternary
} Tertiary
Cretaceous
Jurassic, Undifferentiated~ Jurassic
Older Undifferentiated :Jr-Prejurassic
,.... ----------------------~--------------------~----------------------
See legend on
facing raqe.
Figure 36. Generalized bedrock geology of southeastern Montana.
Base Map from USGS
BASIC CONCEPTS
Although river and stream channels constitute only a small percentage
of the total landscape, their significance is far greater than their areal
extent. A perennial stream channel shows the cumulative influence of the
watershed's geology, climatology, hydrology, and biology, as does the
ephemeral channel in a more complex and poorly understood fashion. The
constraints tmposed by these variables are traditionally categorized as
structure, process, and stage.
The structure of a watershed is determined not only by the sequence and
configuration of the rocks, but also by their geotechnical properties, such
as susceptibility to erosion, mass-failure potential, and infiltrative capacity.
Rivers draining watersheds of differing physical characteristics should differ
systematically in form, pattern, rate of change, and the capacity to do work
(i.e. transport a suspended sediment load, bed load, or solution load). The
degree to which a river is adjusted to the system of structural constraints
surrounding it is a measure of the degree to which the river system has
approached a long-term equilibrium. This quasi equilibrium may have an
important, controlling influence over the kinds of short-term changes the
system may undergo.
11 Process 11 refers collectively to all geomorphic agents at work shaping
the landscape. The agent primarily responsible for shaping a river channel and
a river system is the water flowing in the channel. The magnitude, duration,
and frequency of recurrence of runoff events can be major factors controlling
the character of a river channel. Thus, the erosional form and pa~tern of the
river channel and the form and character of the resulting stream deposits
will reflect both the climatic region in which the riv~r occurs and temporal
climatic change.
The stage of development or evolution of a landscape or a river system is
a function of the passage of time. Accompanying the passage of geologic time
is the progressive erosion of the landscape, the reduction of local relief, and,
with the completion of a full cycle of erosion (in the order of magnitude
oflOOmillion years), the denudational lowering of the entire region (e.g. the
formation of peneplains as used by Alden 1932). When viewed from this geo-
logical context, adjustment of channel grade and form is progressive and con-
tinuous, and the attainment of a balanced or equilibrium state is only possible
at the conclusion of an erosional cycle. For shorter periods of time, it is
possible to identify river systems that make small, incremental changes, but, when
the river system is viewed as a whole, the relationships between channel form,
pattern, and character remain essentially unchanged. During this state of
dynamic equilibrium, minor adjustments in channel morphology result from
variations in the biophysical nature of the watershed but no progressive changes
occur. Thus, the attainment of dynamic equilibrium in the fluvial system
represents the delicate adjustment of the river system to the natural rates of
change of the region's biophysical system. Among the system of independent
99
variables, the rate of Quaternary climatic change resulting in cycles of
glaciation, pluviation, etc. has been the most rapid and, therefore, frequently
the controlling natural variable. Man•s land-use practices, whether agriculture,
urbanization, or resource extraction, are not considered to be natural variables
because man-induced changes in the landscape proceed at rates several orders
of magnitude more rapid than changes induced from the other variables
(Detwyler 1971, Thomas 1956}.
STREAM REGIMEN
Stream regimen is the manifestation of the complex interaction of the
physical and hydraulic features of the channel-sediment-water system under the
external influences of gravity and friction. The fundamental aspects of
stream regimen must, of course, rest upon the hydraulic process attendant
to flow in an open channel complicated by variations due to local differences
in lithology, topography, climate, and vegetation. However, recognizing that
a large number of variables are superimposed upon the basic hydraulic system
provides a basis for understanding the quality and perhaps quantity of change
resulting from man•s impact upon his environment.
If at a given time the stream regimen is adjusted to its boundary variables,
then we may think of the stream as being graded. This graded condition as
envisioned originally by G.K. Gilbert and discussed by Davis (1894) simply
implies a condition of balance between degradation and aggradation and as such
describes a temporarily static system. The temporary nature and adjustability
of this graded condition was emphasized by Mackin (1948}, who stated that the
graded stream is one in which, over a period of years, slope
is delicately adjusted to provide, with available discharge
and with prevailing channel characteristics, just the velocity
required for the transportation of the load supplied from the
drainage basin. The graded stream is a system in equilibrium;
its diagnostic characteristic is that any change in any of the
controlling factors will cause a displacement of the equili-
brium in a direction that will tend to adsorb the effect of
the change.
Thus, it is this temporal condition of equilibrium or near equilibrium which
is striven for by the integration of the physical and hydraulic variables.
The graded stream is commonly considered to be a stream in equilibrium,
or perhaps more appropriately a stream in dynamic equilibrium (Strahler 1952,
Hack 1960) because the system considered is an open system through which there
is a continuous passage of material and energy but no change in the form or
character of the stream segment itself. Disruption of equilibrium through
one or more changes in the variable system results in adjustments in the
form and profile of the stream segment. The magnitude of the resultant
change is linked to the duration of change (Leopold et al. 1964} as well as
to the magnitude and frequency of change (Wolman and Miller 1960).
The morphology of channels and the factors controlling this morphology
have been studied at great length with moderate success over the last few
100
decades. Prominent contributors include Leopold, Wolman, Miller, Schumm,
Langbein, Hack, Rubey, and Strahler. The study of their combined effort
suggests that the morphology of a stable stream channel is determined by the
amount of fine-grained, cohesive sediment in the bed and banks of the channel
and by the discharge and the sediment load that move through the channel (Schurran
1960, 1968). Th~ greater the discharge (Q)f the larger the channel width (W),
depth (D), and meander wavelength (L), the smaller will be the channel gradient
(S). This is expressed in the following relationship:
Q W,D,L
a: s
For a given discharge, channel morphology is chiefly a function of type and
amount of sediment load. 11 A significant increase in the ratio of bed load
to total sediment load (Q 5 ) will cause an increase in channel width, mearider
wavelength, and slope with a decrease in depth and sinuosity (P; ratio of
channel length to valley length)11 (Schumm 1968), as follows:
Q a: W,L,S
s D,P
Examining the basic relationships which exist between discharge (Q),
width (W), depth (D), and velocity (V) as expressed by the equation
Q = WDV
Leopold and Maddock (1953) demonstrate that, for consistent sets of at-a-
station and between-station hydraulic geometry, simple power function relation-
ships exist in the forms:
W = aQb
D = cQf
V = kQm
Moreover, subsequent researchers (Leopold et al. 1964, Emmett 1976-) have
shown that streams with mobile alluvial beds and banks adjust their channels
to accomodate discharge volumes and durations that occur, on the average,
every other year. This bankfull flow frequency recurrence interval (Q 8 = 1.5 yrs)
has been found to be remarkably consistent in arid, semiarid, and humia
temperate regions. The dimensionless ratios of bankfull discharge (Q 8 ) to
channel width at bankfull (W 8), channel area at bankfull (A 8), and channel width-
to-depth ratio at bankfull are found to be highly sensitive indicators of the
stage of equilibrium or disequilibrium in a watershed served by that channel.
For a given geologic substrate, landscape history, and precipitation regime,
consistent regional relationships of the type:
Ws = 1.37 q80.54 (r=0.917)
Ds = 0.25 Q8 °·34 (r=0.887)
As = 0.35 Q8°·88 (r=0.972)
101
where WR is bankfull width, o8 is bankfull depth, As is bankfull area, and Q8 is bankfull discharge may be established by study of the geometry and flow
records for strea~ channels. The above example is derived from ongoing USGS
impact work in the White Cloud Peaks area of prospective open pit mining at
the headwaters of the Salmon River. Comparative exponents for an average
of a large number of midwestern streams yield a width exponent of 0.50 and
a depth exponent of 0.40, while in Alaska the same values are 0.50 and 0.35,
respectively.
While it has been shown that the absolute size of a stream channel is
related to the bankfull flood flow which forms or maintains the channel
(Leopold et al. 1964) it appears that the shape of the channel is independent
of discharge (Schumm 1960). The ratio of width to depth (F) is, however, a
strong function of the percentage of silt-clay in the wetted perimeter of the
channel (M). This relationship takes the form:
F = gMh
where M = Sc x W + Sb x 20 w + 20
Sc = % passing 0.074 mm in bed
Sb = % passing 0.074 mm in bank
0 = channel depth
w = channel width
g = coefficient
h = exponent
In addition, Lane (1935) has shown that in channels carrying silt in
suspension there is a tendency to deposit this material along the margins of
the stream, thus altering the W/0 ratio. Stabilization of this stream-bank
silt is aided by the growth of vegetation and by the high entrainment
velocities required to resuspend this material (Hjulstrom 1935).
Thus, when the stream is graded (i.e., in dynamic equilibrium), channel
morphology is affected by a complex set of independent variables, the most
important of which is the discharge of sediment and water. The nature and
quantity of sediment and water moving through stable alluvial channels
largely determines their morphology. Of the independent variables, the nature
and quantity of sediment and water supplied to the stream are most readily
altered through man•s use and modification of the landscape.
102
VIGIL SITE DOCUMENTATION
The individual Vigil monitoring sites were surveyed, described, and photo-
graphed in a manner conformable to the U.S. Geological Survey (USGS) methodology
outlined by Emmett and Hadley (1968) to ensure the future utility and retrieva-
bility of this data for future researchers. To this end, the Vigil site data
have been organized into a standardized format, including a written description
of the site, maps, photographs of the site conditions, landscape reference
points which will allow a person to find benchmarks in the field, and a tabu-
lation of the original survey data. The complete contents of one folder have
been included in this report as appendix C. Copies of the Vigil site folders,
readily reproducible, have been submitted to each of the following repositories:
1 ) Vi gi 1 Network Repository
Library
U.S. Geological Survey
Washington, D.C. 20242
2) Water Resources Division
Montana Department of Natural Resources
and Conservation
32 South Ewing
Helena, MT 59601
3) Geology Department
University of Montana
Missoula, MT 59801
-Resurvey of these established sites will permit observation of rates of
change in stream channel geometry and pattern, stream bank vegetation, and, at
some sites, the change i~ grain-size distribution of bed and bank sediments.
Thus, it will be possible to identify and measure the rate and character o.f
geomorphic and hydrologic change which characterize relatively undisturbed
watersheds and, through the use of a multiwatershed methodology (Striffler
1965), to compare disturbed watersheds throughout the region.
DATA SYNTHESIS -
In the course of establishing the Vigil monitoring sites, the field parties
also attempted to determine bankfull stage at each site utilizing such evidence
as inflection points in the cross-channel morphology, type and extent of
vegetation, limits of flood debris, and floodplain elevation. Partially due to
the proximity of modifying influences such as agriculture and grazing, but
mainly due to the nature of the streams themselves, the definition of bankfull
stage was difficult and subjective. Computation of bankfull discharge (Q 8 )
or comparative analyses of components of the sites• hydraulic geometry such as
~idth-depth ratios (F) is subject to a considerable amount of nonsystematic
error.
103
In an effort to overcome this problem, yearly peak flow data from 28 crest
or recording streamflow gages in the area with a period of .~ecord ten years or
greater (see figure 37) were compiled. These data were subJect to a Log Pearson
Type III extreme value analysis and a plot derived of discharge vs. re~urrence
interval. From this analysis it was possible to determine for the gag1ng
stations used in the analysis the discharge values corresponding to the 1.5-year
and 25-year flood recurrence intervals (tables 20 and 21).
In a similar fashion, data from the U.S. Department of Commerce•s .. Hourly
Precipitation Data Summaries .. (1948-73) and the data ta~e.CLI~ATEMT (~urry 1973)
were analyzed and recurrence interval plots for 33 prec1p1tat1on stat1ons c?n:
structed. From this analysis it was possible to determine the 24-hour prec~pl
tation event (table 22) which occurs at least once every two ·years (the med1an
of the distribution). This two-year, twenty-four-hour storm is the storm event
frequently chosen to represent a station•s precipitation intensity character-
istics (Reich 1963). The two-year, one-hour rainfall was also determin~d.for
the seven continuous-recording stations in the area (table 23). To fac1l1tate
comparison of the precipitation characteristics of watersheds of differing
sizes, the 25-year, one-hour rainfall data were also derived.
APPLICABILITY OF DATA
One of the biggest problems in studying streams in southeastern Montana is
the lack of discharge data. Most of the larger rivers, such as the Yellowstone
or the Tongue, have records of long duration, but a majority of the crest (
gauges on the smaller streams were not established until the late 195o•s or
early 1960 1 s. There are, of course, many problems encountered when analyzing a
data population using only twelve samples, problems which are compounded by
the difficulties involved in evaluating discharge at a crest gage, but that is
the extent of the data available at this time.
In an effort to establish a relationship having predictive capabilities,
a graph of the 1.5-year discharge versus the drainage basin area (figure 38)
was prepared using the data presented in tables 20 and 21. Station 6, the
Tongue River at Miles City, was excluded because of the flow regulation effects
of the Tongue River Reservoir. This approach was not successful. Stations
along line 1 in figure 38 are on streams flowing int6 this area from the south
and east, and most of the discharge they measure is derived from outside the
study area. The remaining stations measure runoff from within the region, and
it is apparent that not only are their flow characteristic~ different from those
existing on the larger streams, but that they differ considerably among them-
selves as well. Basins of essentially equal area have widely differing bankfull
discharges, as is illustrated by stations 1 (Deep Creek near Kinsey) and 9 (Sand
Creek near Broadus). Both drain about thirty square kilometers, but their
1.5-year.discharges differ by over four thousand percent. There is also a
large scatter when the graph is viewed in terms of equal discharge. Station 1
has a bankfull discharge almost twice that of station 27 (Rosebud Creek near
Forsyth), with less than one percent of the drainage area. A significant number
of streams plot at these extremes, and do so in such a manner as to delineate
an envelope containing most of the data points. Whether or not there is any
justification, let alone predictive value, to lines 2 and 3 of figure 38 depends
entirely on whether there is any physical meaning to the relationships implied.
For.purposes of interpretive analysis, the value given by the o25 JQ 1 5 discharge
rat1o was assumed to be a rough measure of the variability (skewnes~) of each
104
'
'· -·
YEllowsTONE . RIVER BASIN
USGS · STREAMflow ··GAGING STATIONs
·usEd IN Tlu:s STudy ·
See table 20 for identification
of numbered stations.
SOURCE: USDI 1974
0 10 20 40 60 80 100 Miles
~Ui£U~~===I~---.... J1=======11 ...... .£1======~1
0 . 10 20 40 60 80 100 Kilometers
~~~:j~--~~====jl .... ~'==::jl
. ! MUSSELSHELL
I WHEATLAND I ·. ·.\
I G 0 L.D EN . -_· -:--. --L -.) ~ A L L E y . I
I ~------r---
L_
·cARBON
I .
. -_j
I ----.-__ , ... 1_....~._ _ __ __,_
....... ~----·\ --
y E' L L 0 W S. T 0 N E ')
NATIONAL PARK c
YELLOWSTONE
. RIVER BASIN
GARFIELD
I
f
I
I I : . M c ·C 0 N E . I
I
LT~J--~
I
DAWSON
I
L...-, I
·I L_ pRAIRIE L~
;-_..,.._...-,
I .
I 8 7.~.
'I ---,----~L_BORG -7
r-'" . ' . . ~'" I . , .
112 l ~I 0 w D E 'R
SHLAND •. . I I . I
I
. ~--.. :1.
'.
I
I
WYOMING ·. r.
' ' ---1 a -~
.... ~
1 ti:
' tj
J >
J ~
0
~ >
' --,
I ·1
TABLE 20. Bankfull discharge (01.5) for selected USGS Gaging Stations in the Yellowstone River Basin
Map
Number
2
3
4
5
6
8
9
10
11
12
13
14
15
16
17
13
19
20
21
22
23
24
25
26
27
28
Station Name
Deep Creek near Kinseya
Ash Creek near Locatea
Powder River near Locate
Meyers Creek near Locatea
Yellowstone River at Miles City
Tongue River at Miles City
Basin Creek Tributary near
Valborga
Basin Creek near Valborga
Sand Creek near Broadusa
Stebbins Creek near Ashlanda
Stebbins Creek at Mouth
near Ashlanda
Spring Creek near Ashlanda
Spriug Creek near Deckera
Tongue River near Decker
Leaf Rock Creek near Kirbya
Rosebud Creek near Kirbya
Whitedirt Creek near
Lame Deera
Tributary to Rosebud Creek
near Busbya
Little Bighorr. below Pass Creek
Little Bighorn at Stateline
Lodgegrass Creek above
Willow Creek Diversion
Bighorn River near St. Xavier
Little Bighorn near Hardin
Andresen Coullee near Custera
Unknown Creek near Bighorna
Buckingham Coull ee near Meyersa
Rosebud Creek near Forsytha
Snell Creek near Hathawaya
CONVERSIONS: 1 km2 = . 386 mi2
acrest gauge
USGS
Identification
Number
06309080
06309090
06326500
06326400
06309000
06308500
06308200
06308300
06324700
06307760
06307780
06307640
06306900
06306300
06306950
06295100
06295200
06295130
06290500
06289000
06291500
06237000
06294000
06294400
06294800
06294850
06296000
06296100
107
Drainage
Area
(km2)
28.7
17.3
34,172.0
24.8
124,975.0
13,952.0
0.36
28.2
27.5
14.0
53.9
3.8
94.0
3,825.0
15.6
38.6
4. I
3.0
1 '1 09.0
500.0
209.0
50,938.0
3 ,351. 0
6. I
37.8
6.8
3,263.0
27.2
Bankfull
Discharge
(01.5) in
cfs
540.0
10.1
7,800.0
190.0
51,003.0
3,550.0
13.0
86.0
12.5
1.3
53.0
100.0
49.0
3,500.0
29.0
71.0
3.6
2.9
I ,000.0
900.1
365. 1
12,801.0
1 ,500. I
4.7
34.5
13.0
275.0
66.0
025
01:"" 5
6.30
103.90
3.33
8.95
1.71
3.66
38.46
15.70
66.40
38.46
16.00
14.50
28.57
2.31
9.66
9.30
15.07
12.10
3.50
2. 77
3.15
2.77
3.60
10.10
40.58
45.38
7.09
6. 52
Period
of
Record
1962-73
1962-73
1938-73
1962-73
1923-73
1938-73
1955-73
1955-73
1956-73
1963-73
1963-73
1962-73
1958-73
1961-73
1958-73
1960-7 3
1959-73
1963-73
1939-73
1939-73
1939-73
1935-73
1953-73
1963-73
1962-73
1962-73
1948-6':'
1963-73
No. of
Years
Used
12
12
36
12
46
32
16
19
17
11
1 I
12
I 6
13
15
12
15
11
35
35
35
39
21
11
12
12
18
II
TABLE 21. Little Bighorn River Drainage Basin Components.
Maximum Discharge
Contributed Every ~5 Area 1.5 years
Region (km2) (cfs) Ql.5
A. Little Bighorn River Basin below
the state line to (and including)
the Pass Creek Drainage. 609 100 10.00
B. Little Bighorn River Basin below land
excluding the Pass Creek Drainage
to Hardin, not including the
Lodgegrass Creek Drainage. 2,033 135 5.56
c. Little Bighorn River Basin below the
state line to Hardin, not in-
eluding the Lodgegrass Creek
Drainage. 2,642 235 7.45
CONVERSIONS: 1 km2 = .386 mi2
1 cfs = .0283 m3fsec.
NOTE: The purpose of this table is to demonstrate how the data in table 20
can be used to calculate the 1.5-year and 25-year discharges, and their ratio, for
drainage basins within the area monitored by the stations shown in figure USGS.
Values given for the three regions in this table, fo~ example, were calculated
as follows (station numbers are given in parentheses):
QAn = Qn below Pass Creek (#19) -Qn at state line (#20)
QBn = Qn at Hardin (#23) -Qn at state line (#20) -Qn Lodgegrass Creek (#21)
Qcn ~ Qn at Hardin (#23) -Qn below Pass Creek (#19) -Qn Lodgegrass Creek (#21)
Where: n = the recurrence interval of interest
QAn' QBn' QCn = the discharges at recurrence interval n for regions A,
B, and C, respectively.
Qn = the discharge value for recurrence interval n for the indicated gaging
station.
108
I
I
I
TABLE 22. Greatest Two-year, 24-Hour Precipitation Events
Station
Number
2
4
5
6
8
g
10
11
12
13
14
15
16
17
18
lg
20
21
22
23
24
25
26
27
28
2g
30
31
32
33
Station Name
Terry
Mildred
Ismay
Mizpah 4 NNW
Miles City AP
Miles City
Gar! and
Brandenberg
Vol borg
Ashland RS
Sonnette 4N
Sonnette 2WNWa
Broadus
Biddle
Biddle SSW
Moorhead gNE
Otter gssw
Birney 2SW
Decker
Kirby lS
Wyola
Lodgegrass
Ye 11 owta il Dam
Crow Agency
Hardin
Busby
Lame Deer
Colstrip
Hysham 25SSE
Ba 1 l anti ne
Custer
Hysham
Vananda SESE
Forsyth 2E
Weather
Bureau
Number
Bl65
5666
4442
5754
5690
5685
3383
1084
8670
0330
7735 &
7740
1127
0739
0743
5870
6287
0819
2266
4701
9175
5106
9240
2112
3915
1297
4839
1905
4364
0432
2158
435B
8511
JOgg
2-year,
24-hour
Precip.
(in)
1. 53
1. 28
1.30
1. 17
1. 30
1.18
1. 15
1. 50
1.30
1.11
1. so
1. 23
1.15
1. 67
1. 34
1. g5
1.25
1. 20
1. 62
1.27
1. 48
1. 30
1. 33
1.13
1.28
1.17
1. 44
1. 45
1.18
1. 17
1. 32
1.16
1. 38
P25
P2
1.65
2.21
2.46
2. 72
2.08
2.46
3.04
1.83
2. 70
2.34
1.77
1. B7
2.33
1. go
2.01
1.85
2.08
2.68
2.36
1. 6g
2.03
2. 31
2.78
2.40
2.00
2.36
1.87
1. 62
2.54
2.46
2.07
2.07
1. g2
Years of Record Used
194g-5o, 52-72
Jg48-51, 6g
JgsJ-66. 72
JgsJ •. 53-73
1950-72
Jg48-72
lgso-72
Jg39-55
Jg56-58, 60-72
Jg5J-72
Jg4g-S2, 55-60
63-67, 72-73
Jg5J-56, 63, 4fl
Jg65-73, 2WNW
1948, 50-72
19S0-6g, 72
]g63-73
Jgsa-61. 63-71
Jg6J-72
lgS5-68, 71-72
Jgso-51, 60-70
Jg60-61. 63-72
Jg48-72
50-3, 55-61, 63
65-66, 68-73
Jg4a-4g, 63-72
Jg48-50, 53-5B
Jg60-63, 65-72
lg48-51. 53-70
Jg4a-sg, 61-62
1966-70
lg48-55, 57-65
Jg6]-6g
1947-72
Jg5g-6J, 65
Jg6a-6g, 72-73
Jg4a-1g72
Jg55, 57-63
Jg6S-68. 70-73
Jg48-53, 55-72
Jg50-53, 55, 56
58-64, 66, 72-73
1948, 50-57
sg-66, 68-70, 72
SOURCE: U.S. Department of Commerce Jg48-~3. Curry Jg7J.
CONVERSIONS: 1 inch= 2.54 em
aRecords from these two stations were combined.
109
No. of
Years
Used
23
20
21
23
25
23
16
16
22
17
16
24
21
11
13
12
16
15
12
25
]g
12
21
22
]g
20
26
10
25
15
24
15
21
TABLE 23. Greatest Two-Year, One-Hour Precipitation Events
Station
Number
3
6
10
12
21
30
32
Station Name
Ismay
Miles City
Ashland RS
Broadus
Lodgegrass
Custer
Heather
Bureau
Number
4442
5685
0330
1127
5106
2158
Vananda 5 ESE 8511
2-Year,
1-Hour
Precip.
(in. )
0.60
0.69
2.42
2.32
0.61 2.62
0.56 2.59
0.55 3.09
0.47 3.40
0.47 3.40
p2(1 hr)
P2(24 hr}a
0.46
0.58
0.55
0.46
0.37
0.40
0.41
SOURCE: U.S. Department of Commerce 1948-73
CONVERSIONS: 1 inch= 2.54 em
aFrom table 22 ·
Years Used
1951-59,61-65,
67-73
1949-53,55,67,
72,57-60,62-
64,68
1949-52,54,56,
64,58-59,67,
72-73
1949-50,52-63
No. of
Years
Used
20
15
67,69-73 19
1950-57,59,61,
63,66,68-73 17
1957-63,65-68, 14
70-73
1950-53,55,58-
59,61-63,68,
72-73 13
station•s peak flow distribution, representing physically the relative amount
by which a twenty-five-year flood exceeds the capacity of the channel to
accommodate it. Insofar as the 1.5-year discharge approximates the most
frequently occurring value (mode) in these distributions, it represents the
magnitude of the excess that appears most frequently when the amount of water
supplied to a watershed exceeds its demand by the maximum amount conditions
allow. Because this quantity is a measure of the adjustments a watershed
has made to the conditions it experiences most of the time, the Q25 !Q 1 5 ratio expresses the degree of assimilation a watershed has achieveo between
these conditions and the less frequent flood conditions it is subjected to.
This analysis yielded grouping of the data into sets similar to those
illustrated in figure 38 but with even greater scatter of data points.
110
10,000
1000 /."
21e II> -u
c
~ •a _, 0 100 _, _,
Q) el6 01 ...
el3 0
~ u
II>
0
01.5 = 1.18 Ad .700
10
18e
eiO
10 100 1000 10,000 100,000
Drainage Area (Ad) in km2
Figure 38. 1.5-year discharge as a function of drainage area.
While there seems to be a distinct grouping of streams which distinguishes
the major through-flowing streams from the smaller high-plains streams which
derive their flow from regions of lesser precipitation and snowpack, it appears
that both Q1 5 and a frequency ratio such as Q25/Q 1 5 are inadequate measures
upon which to base a predictive model of discharge per unit of drainage-basin
area. A similar broad scatter of data results if the Q2 or Q25 flows are
calculated using the regression equations of the USGS .,Montana Method., for
estimating the magnitude and frequency of floods (8ohnson and Omang 1976).
Errors of estimate in excess of 3000 percent are common to both methods for
similarly sized watersheds in close geographic proximity. From this analysis
it appears clear, however, that the small streams of southeastern Montana are
at least in part adjusted to the less frequent conditions (intense or long-
duration precipitation events) which modify the short-term hydrologic character
of the watersheds.
It has already been noted that bankfull discharge is one indicator of the
conditions prevailing in a watershed that theoreti~ally results from the set
of conditions which occurs most frequently during periods of peak flow. The
most frequently occurring short-term conditions, such as local temperature,
rainfall intensity, and infiltration rates, presumably exert a powerful
influence on the hydrologic character of a watershed, but it would seem that,
in this region, the higher-magnitude flows are the ones which accomplish
regional integration. Thus, because of the nature of a recurrence interval
plot, bankfull discharge (Q 1 5) may be largely a statistical representation
of the interactions between tnese local conditions and the less frequent
regional ones, particularly for ephemeral streams. The statistical analysis
suggests that bankfull discharge occurs not only as a discrete event, b~t
also as a result of conditions which lead to flows of higher magnitude. If
one basin's 25-year flood flows are very much higher than another's, but their
1.5-year discharge is the same, then their Q25/Q1 5 ratios are considerably
different, and the nature of the interactions wh1ch determine that ratio
must also differ. Similarly, when the bankfull discharges of two streams vary,
it is because of significant hydrologic differences in their drainage basins.
The nature of these differences would determine the type of effects the inter-
actions between ~he systems responsible for the frequent hydrologic events and
the systems responsible for the rare ones would have. If an underlying pattern
is apparent in the relationship among the hydrologic variables of a watershed,
then changes in parameters describing their different interactions may be
systematic. Thus, a certain bankfull discharge may imply the existence of
a specific set of local conditions that is different for each subregion and
which interacts with the 25-year flood mechanism so as to give those conditions
more behavioral homogeneity at high flows than at low. The importance of less
frequent flows in semiarid regions is well documented (Wolman and Miller
1960), and studies also indicate that the role of maximum events in determining
the characteristics of a region's channel system can be dominant (Chorley and
Morgan 1962) .
A partial analysis of the precipitation patterns in the area was made in
an attempt to isolate some of the possible reasons for the marked contrast in
discharge data in seemingly similar watersheds. The geographic distribution
of variations in mean annual precipitation, the two-year, 24-hour storm,
and its ratio with the 25-year, 24-hour storm show little congruity with the
observed local variations in runoff. The distribution pattern resulting from
a plot of two-year, one-hour rainfall and the 25/2-year ratio may ultimately
be more useful, but, with the relative paucity of data (seven stations), no
meaningful correlation could be derived.
112
The principal analytical finding of this research has been to demonstrate
clearly that variability of hydrologic and hydrographic variables in the
region is so high that conventional data synthesis and record extension are
not valid. This is a significant finding in considering design and validity
of interpretation of records taken from new short-period gaging stations
established by state and federal agencies. Standard USGS methods of synthesis
will be of dubious value for periods of record that would normally be con-
sidered adequate elsewhere in the United States.
The establishment of the Vigil Network in southeastern Montana permits
the systematic observatirin of chann~l form and pattern with time. Continued
observation of these sites will enable future researchers not only to con-
trast rates of morphologic change at disturbed and relatively undisturbed
sites, but also to isolate the functional variables responsible for the
region's hydrologic character. The implementation of a carefully designed
experimental watershed program would greatly expedite and enhance our under-
standing of the region's hydrologic character.
Perennial streams, particularly those that head in major mountain ranges
in Wyoming and Montana, are amenable_ to predictable hydraulic geometry
relationships. However, the small perennial and ephemeral streams in south-
eastern Montana do not bear the usual relationship between bankfull stage and
recurrence interval. Instead of being characterized by a bankfull flow event
on the average of once every 1.5 years like the regional perennial streams,
the local ephemeral streams achieve that discharge only once every 15 to 25
years, or even less frequently. Additionally, the streams are highly irregular
from site to site so that, for example, the ratio between the 25-year peak
discharge and the 1.5-year peak discharge on streams of a fixed drainage size
varies by a factor of as much as two orders of magnitude between sites separated
by but tens of miles.
113
115
A-1.
A-1.
A-2.
A-3.
PROJECTIONS OF FUTURE US~
FIGURES
The Nine Planning Subbasins of the Yellowstone Basin. . . . . .
TABLES
Increased Water Requirements for Coal Development
in the Yellowstone Basin in 2000 ...
The Increase in Water Depletion for Energy
by the Year 2000 by Subbasin .•......
Feasibly Irrigable Acreage by County and Subbasin
by 2000, ~ligh Level of Development ......•.
. . . . . . .
. . . . . . .
. . . ..
119
119
120
121
A-4. The Increase in Water Depletion for Irrigated Agriculture
by 2000 by Subbasin . . . . . . . • . . . . . . . 122
A-5. The Increase in Water Depletion for Municipal Use by 2000 . 122
A-6. The Increase in Water Depletion for Consumptive Use
by 2000 by Sub.bas in . . . . . . . . . . . . . • . .
117
. . . . . . 123
In order to adequately and uniformly assess the potential effects of water
withdrawals on the many aspects of the present study, projections of specific
levels of future withdrawals were necessary. The methodology by which these
projections were done is explained in Report No. 1 in this series, in which
also the three projected levels of development, low, intermediate, and high, are
explained in more detail. Summarized below, these three future levels of
development were formulated for energy, irrigation, and municipal water use
for each of the nine subbasins identified in figure A-1.
ENERGY WATER USE
In 1975, over 22 million tons of coal (19 million metric tons) were mined
in the state, up from 14 million (13 million metric) in 1974, 11 million (10
million metric) in 1973, and 1 million (.9 million metric) in 1969. By 1980,
even if no new contracts are entered, Montana•s annual coal production will
exceed 40 million tons (36 million metric tons). Coal reserves, estimated at
over 50 billion economically strippable tons (45 billion metric tons) (Montana
Energy Advisory Council 1976), pose no serious constraint to the levels of
development projected, which range from 186.7 (170.3 metric) to 462.8 (419.9
metric) million tons stripped in the basin annually by the year 2000.
Table A-1 shows the amount of coal mined, total conversion production,
and associated consumption for six coal development activities expected to take
place in the basin by the year 2000. Table A-2 shows water consumption by sub-
basin for those six activities. Only the Bighorn, Mid-Yellowstone, Tongue, Powder,
and Lower Yellowstone subbasins would experience coal mining or associated
development in these projections.
IRRIGATION WATER USE
Lands in the basin which are now ei.ther fully or parti.ally irrigated total
about 263,000 ha (650,000 acres) and consume annually about 1,850 hm3 [1.5 mmaf)
of water. Irrigated agriculture in the Yellowstone Basin ha~ been incr~asing
since 1971 (Montana DNRC 1975). Much of ~his expansion can be attributed to
the introduction of sprinkler irrigation systems.
After evaluating Yellowstone Basin land suitability for irrigation, con-
sidering soils, economic viability, and water availability (only the Yellowstone
River and its four main tributaries, Clarks Fork, Bighorn, Tongue, and Powder,
were considered as water sources), this study concluded that 95,900 ha (237,000
acres) in the basin are financially feasible for irrigation. These acres are
identified by county and subbasin in table A-3; table A-4 presents projections
of water depletion.
Three levels of development were projected. The lowest includes one-third,
the intermediate, two-thirds, and the highest, all of the feasibly irrigable
acreage.
118
1 Upper Yellowstone
2 Clarks Fork Yellowstone
3 Billings Area
4 Bighorn
5 Mid -Yellowstone
6 Tongue
7 Kinsey Area
8 Powder
9 Lower Yellowstone
I MUSSELSHELL
I WHEATLAND I .\ , ' GOLDEN ,._-~~ ·-·-·r-·~v_A..:_: ~ .:.._ _·
i_ . ~
Figure A-1. The nine planning subbasins of the Yellowstone basin.
--
I"' lg
\~
I" 0
lo-l __ \>
TABLE A-1. Increased water requirements for coal development in the Yellowstone
Basin in 2000.
Level of
Development
Low
lntennediate
High
Low
Intennediate
High
Low
Intermediate
High
Electric
Generation
8.0
24.0
32.0
2000 mw
6000 mw
8000 mw
30,000
90,000
120,000
I
Coal Development Activity
Gasifi-J
cat ion Sync rude I
COAL MINED (mmt/y)
7.6 0.0
7.6 0.0
22.8 36.0
CONVERSION PRODUCTION
250 mmcfd 0 b/d
250 mmcfd 0 b/d
Ferti -1 1 izer
0.0
0.0
3.5
0 t/d
0 t/d
750 mmcfd 200,000 b/d 2300 t/d
WATER CONSUMPTION (af/y)
9,000 0 0
9,000 0 0
27,000 58,000 13,000
CONVERSIONS: 1 mmt/y (short) = .907 mmt/y (metric)
1 af/y = .00123 hm3fy
Export l
171.1
293.2
368.5
a
31,910
80,210
Strip
r-tining
9,350
16,250
22.980
aNo water consumption is shown for export under the low level of development because, for that
development level, it is assumed that all export is by rail, rather than by slurry pipeline.
119
Total
186.7
324.8
462.8
48.3 50
147,160
321.190
l
TABLE A-2. The increase in water depletion for energy by the year 2000
by subbasin.
INCREASE IN DEPLETION (af/.Yl
tlec. Gasifi-Syn-Ferti-Strip
Subbasin Generation cation crude 1 izer ·Export Mining Total
LOW LEVEL OF DEVELOPMENT
Bighorn 0 0 0 0 0 860 860
Mid-Yellowstone 22,500 9,000 0 0 0 3,680 35 '180
Tongue -7,500 0 0 0 0 3,950 11 ,450
Powder 0 0 0 0 0 860 860
Lower Yellowstone 0 0 0 0 0 0 0
Total 30,000 9,000 9,350 48,350
INTERMEDIATE LEVEL OF DEVELOPMENT
Bighorn 0 0 0 0 4,420 1,470 5,890
Mid-Yellowstone 45,000 9,000 0 0 15,380 6 '11 0 75,490
Tongue 30,000 0 0 0 9,900 7,000 46,900
Powder 15,000 0 0 0 2,210 1,670 18,880
Lower Yellowstone 0 0 0 0 0 0 0
Total 90,000 9,000 31 '91 0 16,250 . 147,160
HIGH LEVEL OF DEVELOPMENT
Bighorn 15,000 0 0 0 11 '1 00 2,050 28,150
Mid-Yellowstone 45,000 18,000 29,000 0 38,700 8,710 139,410
·Tongue 45,000 9,000 29,000 0 24,860 10 '170 118,030
Powder 15,000 0 0 a· 5,550 2,050 22.600
Lower Yellowstone 0 0 0 13,000 0 0 13,000
Total 120,000 27,000 58,000 13,000 80,210 22,980 321 '190
CONVERSIONS: 1 af/y = .00123 hm 3/y
NOTE: The four subbasins not shown (Upper Yellowstone, Billings .Area, Clarks Fork
Yellowstone, Kinsey Area) are not expected to experience water depletion associated
with coal development.
120
TABLE A-3. Feasibly irrigable acreage by county and subbasin by 2000, high level
of development.
Upper Clarks Billings Big Mid Tongue Kinsey Powder Lower County
County ellowstone Fork Area Horn Yellowstone River Area River Yellowstone , Totals
Park
Sweet Gras!
Stillwater
Carbon
Yellow-
stone
Big Horn
Treasure
Rosebud
Powder
River
Custer
Prairie
Dawson
Richland
Wibaux
BASIN
TOTALS
21,664
10,204
6,208
38,076
2,160
2,160
19,412
13,037
9,591
11 ,408
4,230
19,412 13,037 25,229
CONVERSIONS: 1 acre = .405 ha
2,1B5
9,727
10,035
21,947
46,853
3,092 26.438
1,644 1,914 8,231
1B,355
10,421
633
4,736 75,205 37,670
NOTE: The number of irrigable acres for the low and intermediate development levels are one-third
and b1o-thirds, respectively, of the numbers given here. This table should not be considered an exhaustive
listing of all feasibly irrigable acrea9e in the Yellowstone Basin: it includes only the acreage identified
21,664
10,204
6,20?
2,160
19,412
15,222
9,591
21 ,135
46,B53
43,795
11. 7B9
1B,355
10,421
633
237 ,472
as feasibly irrigable according to the geoqraphic and economic constraints explained elsewhere in this report.
MUNICIPAL WATER USE
The basin's projected population increase and associated municipal water
use depletion for each level of development are shown in table A-5. Even the
13 hm3/y (10,620 af/y) depletion increase by 2000 shown for the highest develop-
ment level is not significant compared to the projected depletion increases for
irrigation or coal development. Nor is any problem anticipated in the availability
of water to satisfy this increase in municipal use.
WATER AVAILABILITY FOR CONSU~1PTIVE USE
The average annua1 yield of the Yellowstone River Basin at Sidney, Montana,
at the 1970 level of development, is 10,850 hm3 (8.8 million af). As shown
in table A-6, the additional annual dep1etions required for the high projected
level of development total about 999 hm (812,000 acre-feet). Comparison of
these two numbers might lead to the conclusion that there is ample water for
such development, and more. That conclusion would be erroneous, however,
because of the extreme variation of Yellowstone Basin streamflows from year
to year, from month to month, and from place to place. At certain places and
at certain times the water supply will be adequate in the foreseeable future.
But in some of the tributaries and during 1ow-flow times of many years, water
availability problems, even under the low level of development, will be very real
and sometimes very serious.
121
TABLE A-4. The increase in water depletion for irrigated agriculture by 2000
by subbasin.
Subbasin
Upper Yellowstone
Clarks Fork
Bi 11 i ngs Area
Bighorn
Mid-Yellowstone
Tongue
Kinsey Area
Powder
Lower Yellowstone
TOTAL
Acreage
Increase
HIGH LEVEL OF DEVELOPMENT
38,080
2 '160
19,410
13,040
25,230
21,950
4,740
75,200
37,670
237,480
Increase in
Depletion (af/y)
76,160
4,320
38,820
26,080
50,460
43,900
9,480
150,400
75,340
474,960
INTERMEDIATE LEVEL OF DEVELOPMENT
BASIN TOTAL 1 158,320 316,640
LOW LEVEL OF DEVELOPMENT
BASIN TOTAL 79,160 158,320
CONVERSIONS: 1 acre = .405 ha
1 af/y = .00123 hm3fy
NOTE: The numbers of irrigated acres at the low and intermediate
levels of development are not shown by subbasin; however, those numbers
are one-third and two-thirds, respectively of the acres shown for each
subbasin at the high level of development.'
TABLE A-5. The increase in water depletion for municipal use by 2000.
Level of Development
Low
Intermediate
High
Population
Increase
56,858
62,940
94,150
CONVERSIONS: 1 af/y = .00123 hm3/y
122
Increase in
Depletion (af/y)
5,880
6,960
10,620
l
)
TABLE A-6. The increase in water depletion for consumptive use by 2000
by subbasin.
Increase in Depletion (af/y)
Subbasin Irrigation Energy Municipal Total
LOW LEVEL OF DEVELOPMENT
Upper Yellowstone 25,380 0 0 25,380
Clarks Fork 1 ,440 0 0 1 ,440
Bi 11 i ngs Area 12,940 0 3,480 16,420
Bighorn 8,700 860 negligible 9,560
~lid-Yellowstone 16,820 35 '180 1 ,680 53,680
Tongue 14,640 11 ,450 negligible 26,090
Kinsey Area 3,160 0 0 3,160
Powder 50' 140 860 360 51 ,360
Lower Yellowstone 25 '120 0 360 25,480
TOTAL 158,340 48,350 5,880 212,570
INTERMEDIATE LEVEL OF DEVELOPMENT
Upper Yellowstone 50,780 0 0 50,780
Clarks Fork 2,880 0 0 2,880
Billings Area 25,880 0 3,540 29,420
Bighorn 17,380 5,890 300 23,570
Mid-Yellowstone 33,640 75,490 1 ,360 110,990
Tongue 29,260 46,900 300 76,460
Kinsey Area 6,320 0 0 6,320
Powder 100,280 18,880 600 119,760
Lower Yellowstone 50,200 0 360 50,560
TOTAL 316,620 147,160 6,960 470,740
HIGH LEVEL OF DEVELOPMENT
Jpper Yellowstone 76,160 0 0 76,160
Clarks Fork 4,320 0 0 4,320
Billings Area 38,820 0 3,900 42,720
Bighorn 26,080 28,150 480 54' 710
Mid-Yellowstone 50,460 139,410 3,840 193,710
Tongue 43,900 118,030 780 162,710
Kinsey Area 9,480 0 0 9,480
Powder 150,400 22,600 1 '140 174,140
Lower Yellowstone 75,340 13,000 480 88,820
TOTAL 474,960 321 , 1 CIO 10,620 806,770
CONVERSIONS: af/y =· .00123 hm3;y
123
BIGHORN RIVER MORPHOLOGY PRIOR TO AND AFTER YELLOWTAIL DAM
FIGURES
B-1 Vegetated islands on the Bighorn River by area categories
prior to and after Yellowtail Dam ............ .
B-2 Island gravel bars on the Bighorn River by area categories
prior to and after Yellowtail Dam .......... .
B-3 Absolute numbers of lateral gravel bars on the Bighorn River
by area categories prior to and after Yellowtail Dam ..
B-4 Percentages of vegetated islands on the Bighorn River by
area categories prior to and after Yellowtail Dam ....
B-5
B-6
B-1
B-2
B-3
B-4
B-5
B-6
Percentages of island gravel bars on the Bighorn River by
area categories prior to and after Yellowtail Dam .....
Percentages of lateral gravel bars on the Bighorn River by
area categories prior to and after Yellowtail Dam .....
TABLES
Vegetated islands on the Bighorn River prior to and after
Yellowtail Dam . . . ..... .
Island gravel bars on the Bighorn River prior to and after
Yellowtail Dam . . . . . . . . . ...
'
Lateral gravel bars on the Bighorn River prior to and after
Ye 11 owta i 1 Dam . . . . . . · . . . . . . . . . . . . . . . . .
Percentages of vegetated islands on the Bighorn River prior
to and after Yellowtail Dam • . . . . ...
Percentages of island gravel bars on the Bighorn River
prior to and after Yellowtail Dam ......... .
Percentages of lateral gravel bars on the Bighorn River
prior to and after Yellowtail Dam .......... .
125
126
128
130
132
134
136
127
129
131
133
135
137
20
15
10
5
0
30
25
20
15
10
5
0
35
30
25
20
15
10
5
0
25
Section I Section 4
20
15
10
5
0
Section 2
25
20 Section 5
15
10
5
0
120
Section 3 110 Total
100
90 1974
80 1939
.... 70
Q)
.0 60 E
::J z 50
40
30
I 20
10
0
Figure B-1. Vegetated islands on the Bighorn River by area categories
prior to and after Yellowtail Dam.
126
__,
N
"'-J
TABLE B-1. Vegetated islands on the Bighorn River prior to and after Yellowtail Dam.
River Section
Prior to Yellowtail Dama After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3
1
2
3
4
5
6
7
8
9
10
(acres) Number
0 -1.00 19 16 31 21 22 109 19 28 7
1. 01 -2.00 11 13 9 8 12 53 5 15 8
2.01 -3.00 4 8 11 7 7 37 4 6 6
3.01 -4.00 1 4 8 5 4 22 2 7 6
4.01 -5.00 1 2 2 5 3 13 3 1 4
5.01 -10.00 8 11 17 11 6 53 3 8 3
10.01 -20.00 5 15 10 11 6 47 2 6 6
20.01 -50.00 3 11 14 11 4 43 3 9 7
50.01 -100.00 1 3 6 9 5 24 -3 4
100.01 + 1 2 7 2 1 13 1 1 5
TOTAL NUMBER 54 85 115 90 70 414 42 84 56
AVERAGE SIZEc 8.5 15.2 18.7 17.4 12.6 15.4 8.5 9.8 25.8
TOTAL AREAd 459 1294 2155 1567 884 6360 355 823 1447
aTaken from 1939 aerial photographs except section 5 taken from 1950 photographs.
bTaken from 1974 aerial photographs.
cRounded to the nearest 0.1 acre.
dRounded to the nearest acre.
4 5
14 12
9 5
7 -
7 4
3 2
5 2
8 4
4 7
4 1
5 2
66 39
20.1 24.2
1323 942
Total
Number
80
42
23
26
13
21
26
30
12
14
287
17.0
4891
20
10
30
20
10
50
40
30
20
10
0
70-
Section I
so-
50-
40-
Section 2 Section 5
30-
20-
10-
O --+'""'"'1..,.= 1 2""'1 3 I 4 I 5 1 6 I 7 1 8 1 9 1 10 1
Section 3
160
150 Total
140
130 1974
120 1939
110
100
... 90
Q)
..c 80 E
~
Section 4 z 70
60
50
40
30
20
10
0
Figure B-2. Island gravel bars on the Bighorn River by area categories
prior to and after Yellowtail Dam.
128
__,
N
1.0
.. : .... \_;
TABLE B-2. Island gravel bars on the Bighorn River prior to and after Yellowtail Dam.
River Section
Prior to Yellowtail Dam a After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3
1
2
3
4
5
6
7
8
9
10
(acres) Number
o-... o.5o 20 28 30 8 65 151 20 20 12
0.51 -1.00 10 16 24 18 18 86 13 23 23
1.01 -2.00 14 24 41 30 18 127 8 16 22
2.01 -3.00 11 17 29 21 4 82 -10 9
3.01 -4.00 6 7 15 4 3 35 1 4 6
4.01 -5.00 3 5 13 8 2 31 -2 2
5.01 -6.00 5 3 7 4 1 20 --3
6.01 -10.00 6 17 13 13 1 50 ---
10.01 -20.00 4 10 11 5 1 31 ---
20.01 + -4 -2 -6 ---
TOTAL 79 131 183 113 113 619 42 75 77
AVERAGE SIZEc 2.8 3.9 3.0 3.8 0.9 2.9 0.7 1.3 1.5
TOTAL AREAd 219 508 548 433 106 1814 30 95 119
aTaken from 1939 aerial photographs except section 5 taken from 1950 photographs.
bTaken from 1974 aerial photographs.
CAverage size rounded to nearest 0.1 acre.
dTota1 area rounded to nearest acre.
4
19
11
13
6
4
5
2
-
1
-
61
1.7
103
5 Total
Number
15 86
11 81
12 71
-25
3 18
2 11
2 7
1 1
-1
--
46 301
1.5 1.4
67 413
15
10
5
15
10
5
15
10
5
15
10
5
15
Section I Section 5
10
5
Section 2
Section 3
35
Total
30
1974
25 1939
6 7
20 ....
Cl)
.0
E
::1 15 z
Section 4
10
5
0 ~~~~~~~~~~~~~
I
Lateral Grovel
Figure B-3. Absolute numbers of lateral gravel bars on the Bighorn River~
by area categories prior to and after Yellowtail Dam.
130
r~, . r·· .-.. ~
··~ { '~.-• .. . . \ ;'
I
TABLE B-3. Lateral gravel bars on the Bighorn River prior to and after Yellowtail Da;.·
River Section
Prior to Yellowtail Dam a After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3
(acres) Number
1 0 -0.50 4 3 2 -9 18 6 3 2
2 0. 51 -1.00 3 10 -4 3 20 5 5 9
3 l. 01 -2.00 7 10 4 8 3 32 7 5 3
4 2.01 -3.00 6 7 4 1 1 19 -3 5
5 3.01 -4.00 -2 -3 1 6 1 4 4
6 4.01 -5.00 2 2 3 --7 1 -1
7 5.01 -6.00 --------1
8 6.01 -10.00 3 4 2 2 1 12 -1 1
9 10.01 -20.00 1 l 1 3 l 7 -2 2
10 20.01 + -1 ---1 ---
TOTAL 26 40 16 21 19 122 20 23 28
AVERAGE SIZEc 3.1 3.0 3.9 4.3 1.7 3.2 1.2 2.7 2.9
TOTAL AREAd 81 120 62 91 32 385 25 61 81
gTaken from 1939 aerial photographs except section 5 taken from 1950 photographs.
Taken from 1974 aerial photographs.
CAverage size rounded to nearest 0.1 acre.
dTotal area rounded to nearest. acre.
4
2
7
5
4
1
3
-
-
-
-
22
1.8
40
5 Total
Number
2 15
4 30
4 24
2 14
2 12
1 6
-1
3 5
-4
--
18 111
2.7 2.3
48 254
50
40
30
20
10
0
40
30
20
10
0
40
30
20
10
Section I
Section 2
Section 3 Cl)
01 c -c
Q)
u ...
Q) a..
40
30
20
10
0
40
30
20
10
0
40
30
20
10
0
Section 4
Section 5
Total
~@li
1974
1939
Figure B-4. Percentages of vegetated islands on the Bighorn River by
area categories prior to and after Yellowtail Dam.
'-1
......
w w
TABLE B-4. Percentages of vegetated islands on the Bighorn River prior to and after Yellowtail Dam.
River Section
Prior to Yellowtail Dam a After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3 4 5
(acres}
1 0 -1. 00 35c 19 27 23 31 26 45 33 13 21 31
2 1.01 -2.00 20 15 8 9 17 13 12 18 14 14 13
3 2.01 -3.00 7 9 10 8 10 9 10 7 11 11 -
4 3.01 -4.00 2 5 7 6 6 5 5 8 11 11 10
5 4.01 -5.00 2 2 2 6 4 3 7 1 7 5 5
6 5.01 -10.00 15 13 15 12 9 13 7 10 5 7 5
7 10.01 -20.00 9 18 9 12 9 11 5 7 11 12 10
8 20.01 -50.00 6 13 12 12 6 10 7 11 13 6 18
9 50.01 -100.00 2 4 5 10 7 6 -4 7 6 3
10 100.01 + 2 2 6 2 1 3 2 1 9 7 5
:Taken from 1939 aerial photographs except section 5 taken from 1950 photographs.
Taken from 1974 aerial photographs.
Cpercentages rounded to nearest whole number.
Total
28
15
8
9
5
7
9
10
4
5
60
50
40
30
20
10
0
40
30
20
10
0
40
30
20
10
40
Section 4
30
Section I 20
10
0
60
50
40 Section 5
Section 2
30
20 I '::".2,~::::~· I
10
0
40
Section 3 Total
30
Q)
tJI
0 -20 c::
Q)
u
illtlti 1974
1939 ....
Q) a..
10
0
Figure B-5. Percentages of island gravel bars on the Bighorn River by
area categories prior to and after Yellowtail Dam.
134
__,
w
()"I
----------------------------------------~------·--
TABLE B-5. Per~entages of island gravel bars on the Bighorn River prior to and after Yellowtail Dam.
River Section
Prior to Yellowtail Dama After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3
l
2
3
4
5
6
7
8
9
10
{acres)
0 -0.50 25c 21 16 7 58 24 48 27 16
o. 51 -1.00 13 12 13 16 16 14 31 31 30
1.01 -2.00 18 18 22 27 16 21 19 21 29
2.01 -3.00 14 l3 16 19 4 13 -13 12
3.01 -4.00 8 5 8 4 3 6 2 5 8
4. 01 -5.00 4 4 7 7 2 5 -3 3
5.01 -6.00 6 2 4 4 1 3 --4
6.01 -10.00 8 13 7 12 1 8 ---
10.01 -20.00 5 8 6 4 l 5 ---
20.01 + -3 -2 -1 - -
-
aTaken from 1939 aerial photographs except section 5 taken from 1950 photographs.
bTaken from 1974 aerial photographs.
~Percentages rounded to nearest whole number.
tr = trace; a value less than 0.50 percent.
4
31
18
21
10
7
8
3
-
2
-
5
33
24
26
-
7
4
4
2
-
-
Total
29
27
24
8
6
4
2
trd
tr
-
40
30
20
40
30
20
10
40
30
20
10
40-
Section I Section 4
30-
20-
10 -!,_-.:.~_,.· __ .r_:_.t __ .: __ : __ ,.~_.:_:_,:_,·,·.l_,·,:_.':_•_,~ __ .i:.: ,=, : .. :; ~ ll~il~~ o_....=-+=-.~~~~.......,---41---,.-+--, 2 I 3 I 4 I 5 6 I 7 8 1 9 10 l
50
Section 2 40
Section 5
30
40
Section 3 Total
30
Cl)
Cl
0 ... 20 c
Cl)
0 ....
IR\111 1974
1939
Q) a..
10
0
Figure B-6. Percentages of lateral gravel bars on the Bighorn River by
area categories prior to and after Yellowtail Dam.
136
TABLE B-6. Percentages of lateral gravel bars on the Bighorn River prior to and after Yellowtail Dam.
River Section
Prior to Yellowtail Oama After Yellowtail Damb
Area Category 1 2 3 4 5 Total 1 2 3 4 5 Total
(acres)
1 0 -0.50 15c 8 12 -47 15 30 13 7 9 11 14
2 0.51 -1.00 12 25 -19 16 16 25 22 32 32 22 27
3 1.01 -2.00 27 25 25 38 16 26 35 22 11 23 22 22
4 2. 01 -3.00 23 18 25 5 5 16 -13 18 18 11 13
I
5 3.01 -4.00 -5 -14 5 5 5 17 14 5 11 11
6 4.01 -5.00 8 5 19 --6 5 -4 14 6 5
7 5.01 6.00 -----4 1 ------
8 6.·01 -10.00 12 10 12 10 5 10 -4 4 -17 5
9 10.01 -20.00 4 2 6 14 5 6 -9 7 .., -4
10 20.01 + -2 - --1 --- -
--
gTaken from 1939 aerial photographs except section 5 taken from 1950 photographs.
Taken from 1974 aerial photographs.
CPercentages rounded to the nearest whole number.
SAMPLE CONTENTS OF VIGIL NETWORK SITE FOLDER
Site MY-1: Armells Creek.at Frieze Ranch
Items
1. Index Card
2. Surveyor•s Narrative
3. Tabulated Survey Data
4. Sediment Samples
5. Vi gil Network
6. Site Location
7. Tabulated Survey Data
8. Vegetation Transects
9. Site Location
10. Legend and Survey Map
11. Photographic Record
Description
Purpose of site, type of data collected,
cross reference to other data applicable
to site. . . . . . . . . . . . . . .
Description of site location and benchmarks.
Angles, directions, distances ..
Location of sampling with reference
to benchmarks and notes on procedures
used . . . . . . . . . . . . . . . . .
List of sites and identifying numbers.
AMS Map . . . . . . . . .
Cross-section elevations
Vegetational types with reference to
cross sections ...
USGS Quadrangle map ......... .
Survey date, location of benchmarks,
viewpoints of photographic record ..
.................
139
140
141
142
143
144
145
146
150
153
154
156
__,
-'=" 0
VIGIL NETWORK SITE
INDEX CARD
Card No. SITE # flY - 1
T~ ~~~~~~~------Da~ July 23, 1975
Sitenamc Annells Creek-Location Yello\':stone.River Dasin; Soutbc..astcrn r~ontana
Frieze P-anch
Principal site investigator Rohert R. Curry Address University of t·lontau..u.n ..... a ____ _
Purposes (ch~k; if more than one, number in order of importance):
Channel change _l_ Erosion _A__ Sedimentation __3___ Mass movement ___ Vegetation _2__
Numhcr and type of observations (if applic."tble, wri~ number of such installations):
Stream channels
Channel cross sections __3_
Scour chains _Q__
Bed profile _Q__
Water-surface profile _Q__
Discharge:
Crest-stage gage ~
Gaging station __n_o_
Suspended sediment.D1L
Chemical _lLQ_
Other (specify)benthic fauna
Vegetation
Transects _3__
Quadrats _no_
Grasses ~-• shrubs~,
trees~
Tree-ring data ..D..Q_
Other (specify)
Hillslapea
E roo.ion stakes -----
Mass-movement pins -------
Paint.od rock lines-----
Cli!T-reccssion markers------
Profiles -----
Water runoff-----
Other (specify)
Other
Reservoir sedimentation ---"n"-'0=----
Rain gage --'-'n-"'0'--------
Soil chemistry ---LOuOJ----
Soil moisture _un...,o ____ _
Particle size:
Streambed _.J..y=.e~s __ _
Bank yes
Hillslope un~o ____ _
Pollen ____c::..::._ __ _
Other (specify)
Further data • 2 807 km If a~ba.sin, drainage area --=..::.:......:.:.:::.:.... __
IC a plot-------
Elev _____ _
A~ precipitation ------
Relief------
Geology:
Vegetation:
Hydrology: w/ d @ B .. F. Stage 17.3
Slope m/m .0923
Photography: yes; 7 exposures
Other: Griffin Coulee
Quadrang.le; 7 ~·
A 1973 survey also exists.
• Include units of measurement, metric
or English
Si~~am order ri:4
Site Location
/\Rt1ELLS CREEK
L. Frieze Ranch
SITE # HY -1
The site is 17~ miles north of the main turnoff into Colstrip, r'lontana,
or 11.4 miles south of the 14 94 exit st6p sign, on 315. Go west on the
gravel road, crossing the railroad and the first bridge, stoppinq on the
west side of the first cattleguard past the bridge. The owner, L. Frieze,
lives north of the site on the first farm to the t/est of the highway.
This site was originally surveyed by 11axfield and Laudry (University
of.Montana, 1973, unpublished survey notes, site #25).
Description of Benchmarks
Angles determined by Brunton are follm-1ed by·a (R), all others \'/ere
derived from plane tahle data. Distances determined with a. tape are follO\'Ied
by a (T), all others were found using the alidade. The rod is touching
the alidade side .of the survey point and i~ centered. Compass compensation
is 15~0 , t1L refers to t·1axfield and Laudry, 1973.
All benchr:-rarks are ·pieces of rehar about 18 inches long driven
flush ~Ji th the qround and spray rain ted orange.
The Primary reference {P.R.) is the \'IOOden corner fence in thP. fence
which runs from the cattleguard strearm-Jard. It is one end of a qate.
The Secondary Reqerence {S.R.) is the first, and only, tree south along
the fence from the gate.
BM 2 is at about the same elevation as BM 1, being about 1 meter
upstream from the edqe of a srnall (approximately 3 rn. wide), shallo\'t qully.
13M 3 is almost exactly on a line connecting rm 1 and the lone large
tree in approximately a 203° dirction from f3f1 1, heing sliqhtly streamward.
13M 1 to AM 3 to EM 5 to tree is not quite a straiqht line.
See Table 1-1.
Date surveyed = 7/23/75.
141
'·
Table 1-1
SIIOOTHlG
(m.) FROH: TO: DIRECTION DISTANCE
P.R. !3t·1 1 123° 32
S. R. 131-1 1 69° 37
S. R. 13f·1 3 11t (13)
S. R. 131·1 5 15!?(13)
13t1 2 131·1 4 180° (T) 17.8
Bt~ 1 Bf1 2 96~ 30 f.1L' s was
( taped)
31.3
131·1 1 . m~ 3 203" 25
Bt·1 1 13t·1 4 124..: 38
13t1 1 rm 6 146 c 57
BH 1 1311 5 204c 50
13H 3 rm 4 R7° 41
13H 3 131·1 6 123"(13)
1311 4 Bt1 6 181" (13) 27.3 (T)
lone cottom-1ood 13H 5 25° 14 203" from 13f.1 1
13f·1 5 13f·1 6 51
142
Sediment Samples
BM 1 to BM 2:
#1) Taken on northern most bank (still in water & closest to BM 1).
#2) Taken in midchannel.
#3) Taken on southern most bank (in water & closest to BM 2).
BM 3 to Bt·1 4 :
#1 Taken in water on northern hank (closest to BM 3).
#2) Taken in mid channel.
#3) Taken in water pn southern bank (closest to 8~1 4).
BM 5 to BM 6:
#1) Taken on northern bank, in \'later closest to 8~1 5.
#2) Taken on southern bank, in water closest"t to Br1 6.
#3) Taken in midchann~l.
These two ended up in the wrong hags, therefore bag #2 reads mid-
channel, but actually is southern bank closest to BM 6; and bag #3
reads southern bank, but is actually midchannel.
143
UfHVERSITY OF t·tONT.AJIA
YELLOHSTOf-IE VIGIL tiETUORK SITES
Site Title
Armells Creek -L. Frieze Ranch
Rosehud Creek -Helvey Ranch
Hest Fork f1uddy Creek -Cheyenne Reservation
East Fork Sarpy Creek -Peddinq Ranch
Ephemeral Tributary to Rosebud Creek -
S\'teedl and Ranch
West Fork Tullock Creek -
Crow Reservation
North Fork Rosebud Creek -
Anderson Michael Ranch
South Fork Rosebud Creek -
Anderson Michael Ranch
Main Stem Rosebud Creek -
Anderson Michael Ranch
Lm·1er Tullock Creek -Haynie Ranch
Lower Sarpy Creek -Lyle Ballard Ranch
Lovter Owl Creek -f·1urray Brovm Ranch
Sarpy Creek -below bridge on Colstrip Road
Upper 0\-1l Creek -tro\'t I Scott Land
tH d 0.'11 Creek -Crow I Scott Land
Otter Creek -Trusler Ranch
Otter Creek -Shy Ranch
Logging Creek -Cheyenne Reservation
Pumpkin Creek
Pumpkin Creek -Roqer Ranch
Tributary to Hollm·Mood Creek
144
Site tlumbe r
Site # HY -1
Site # r-w - 2
Site # r1Y -3
Site # tW -4
Site # rw -5
Site # rw -6
Site # t.W -7
Site # MY -8
Site # MY -9
Site # ~1Y -10
Site # MY -11
Site # NY -12
Site # rw -13
Site # fvJY -14
Site # HY -15
Site # t1Y -16
Site # t1Y -17
Site # NY -18
Site # tW -19
Site # MY -20
Site # t1Y -21
Site # rw -22
Scale I :250,000
=~=======13:0====:::=:=====':;5~:========:320 Statute Miles I 0 15 20 25 30 Kilometers ~=i=====:::::.~===,;:o=3:=====:::::.~==,=5=N;=au"l3ical Miles
LOCATION DIAGRAM
~ INTERVAL 100 FEET
145
Table 1-2
CROSS SECTIOilS: ARI~ELL Is CREEK SITE # 11Y -1
All distances measured with the alidade.
STATION DISTAilCE (m.) ELEVATION (m.) REMARKS
( re 1 at i ve to:)
[pl1 1_tq_Jill_~ (Bt·1 1)
1. 30 -0.09 at BM 2
2. 29 -0.09
3. 27 -0.30
4. 26 -0.80
5. 26 -1.16
6. 25 -1.24
7. 25 -1.71 end veqetation
8. 24 -1.97 edge of water
9. 24 -2.12 \·tater surface = 0.15 r.l.
10. 22 -2.20
11. 20 -2.16
12. -2.20 error in readin~.s
13. 19 -2.24 sinking to knees in mud
14. 18 -2.15
15. IE -2.12 Hater S11rfrtc:P. = 0.1:1 m.
16. 15 -2.06 edge of water
17. 14 -1.67 top of vert i ca 1 hank
18. 13 -1.52
19. 11 -1.52
20. 8 -0.55
21. 7 -0.07 one foot from # 20
146
CROSS SECT! OilS: Table 1-2 (cont.)
STATION DISTANCE (~.) ELEVATION (m.) REMARKS
(relative to:)
22. 5 +0.06
([t1 3..=t.Q_~.!Ul (BM 3)
1. 41 -0.05 at BH 4
2. 37 -0.12 top of cut hank
3. 37 -1.18 hottom of cut bank
4. 36 -1.62
5. 34 -1.78
6. 33 -2.03 edge of water & vegetation
7. 33 -2.29 water surface = 0.26 m.
8. 31 -2.36
9. 30 -2.34
p.b
10. 27 -2.18 water surface =.15m., • 35 m. soft
11. 28 -2.13
12. 26 -2.12 water surface = 0.1 m.
13. 25 -2.04 edge of water & veqetation
14. 25 -1.56
15. 23 -1.35 bankfull
16. 21 -1.33
17. 17 -1.33 (questionable shot)
18. 13 -1.19 toe hasin terrace riser
147
CROSS SECT! OilS: Table 1-2 (cont.)
STATION DISTANCE (rn.) ELEVATION (m.) REMARKS
(re 1 ati ve to:)
19. 9 -0.06
20. 5 +0.04
[m1 s to BM 6) (BM 5)
1. 51 -0.05 at 11M 6
2. 48.5 -0.10 break in slope
3. 48 -1.16 toe of slope
4. 46 -1.65 bankfull
s. 45 -1.98
6. 44 -2.16 edge of water
7. 42 -2.29 water surface = 0.205 m.
8. 42 -2.36 veg. clump in middle of stream
9. 40 -2.40 veg. clump in middle of stream
p.c
10. 38 -2.30 veg. clump, depth of water = .OS m.
11. 38 -2.15 water ed~e
12. 37 -1.78 break in slope
13. 35 -1.60 estimated bankfull stage?
14. 29 -1.27
15. 23 -1.11
16. 15 -0.78
17. 9 -0.67 toe of terrace
148
... -,
CROSS SECTIOilS: Table 1-2 (cont.)
STATION DISTANCE (in.) ELEVATION (m.) REM/\RKS
re 1 ati ve to:
18. 5 -0.12 top of terrace
149
p. d
VEGETATION TRAtlSECTS ARMELL'S CREEK SITE #MY 1 Table 1-3
DISTANCE {M) VEGETATION TYPE DISTAUCE {t·1) VEGETATIOU TYPE
8~1 3 to BM 4
1 grass 1 grass
2 bare 2 grass
3 grass .3 grass
4 grass 4 grass
5 grass 5 grass
6 grass 6 grass
7 grass 7 grass
8 bare 8 grass, herbs
9 forb {clover-like) 9 grass
10 forb 10 grass, herbs
11 f-orb, grass 11 grass, forbs
12 grass 12 grass, forbs
13 grass 13 grass, herbs, forbs -·
14 sedge, grass 14 herbs, grass ':-~._
[.
15 sedge 15 grass
..
16 bare (edge of stream) 16 grass, herb 'I
17 grass 17 sage
18 forb, grass 18 sage, qrass
19 grass, forb 19 grass, sage
20 grass, unknown #1 20 forb, !lrass
21 grass, unknown #I 21 forb, herb, qrass
22 sawqrass, ~rass
150
p. b
VEGETATION TRAUSECTS Table 1-3 (cont.)
DISTANCE (M) VEGETATION TYPE DISTAUCE (~1) VEGETATIOU TYPE
23 sawgrass u qrass
24 sawgrass 12 grass
25 sawgrass, sedge 13 grass
26 sedge (\'later edge) 14 sage, grass
27 sedge (8.5 edge of water) 15 sage, grass
28 sedge, sawgrass 16 qrass, sage
29 sedge, grass 17 grass
30 forb, sage, grass 18 grass
31 bare 19 grass
32 grass, berb (3.9 edge of 20 grass
33 grass 21 grass
34 grass 22 grass
23 grass
BM 5 to BM 6 24 grass, herb
1 sage, grass 25 grass
2 grass, saqe 26 grass
3 sage, grass 27 grass, forb
4 grass 28 grass, forb
5 herb, grass 29 grass
6 herb, grass 30 grass, forb, herb
7 grass 31 grass
8 grass, forb 32 grass. herb
9 sage, grass, forb 33 grass, forb
10 grass 34 forb, grass
151
p. c
VEGETATION TRAtiSECTS Table 1-3 (cont.)
DISTANCE (M) VEGETATION TYPE DIS TAI'lCE (t·1) VEGETATIOU TYPE
35 grass, sawgrass, sage
36 sawgrass
37 sedge
38 sedge, (edge of water)
39 sedge, grass (edge of water)
40 sedge
41 sawgrass
42 .grass, forb, herb
43 bare
44 grass, (3.3 m. top of cutbank)
45 grass
46 forbs, grass
152
M
1.0
r-
EXPLANATION
BM •••.••••.•••. Benchmark
~ ••.•••••••••• Instrument Station
0 ............. Benchmark or Reference Point
P.R .••••••••••• Primary Reference
S.R •••••••••••• Secondary Reference
T.R .••••••.•••• Tertiary Reference
Q.R •••••.•••••. Quaternary Reference
T. N •..•.•..•... True North
M.N ••••.••.•••• Magnetic North
<P •.••••••••••• Telephone Pole
tf'irJ ....•........ Tree
@ ............. Bush or Shrub
~5 • • • • • • ••••••• Photograph Sta.
(roll #: exposure #)
....................... Fence
154
.{:
T.ll. 11.11.
ARMELLS CREEK
MY-I
-
--... ---... ... --.... .... --...
1:8
,I, -... ... ,, ... ,
/ , , .. ',
BMCt2.
EROSION
PINS
University of Montana
Vigil Network Site MY-I
Surveyed: 7/23/75
Located: 17 mi. NW of
Colstrip-GRIFFIN COULEE QUAD.
L-..1 2m
0
"' ~-. '\ -r ' C ·I} 1
\. ~1 "-• r , f ' .
_. r' .. 1 ·I -
->" ·'' ,I [
=oo
~
0
; .
r '---~ , ·~ ) '
c. .
.:~ •. ~::~,~~ .• -._, ~y~ ),~J
156
157
Alden, W.C. 1932. Physiography and glactal geology of eastern Montana and
adjacent areas. U.S. Geological Survey Professional Paper 174. U.S.
Government Printing Offtce: Washtngton, D.C. 133 pp.
Andrews, N. 1976. U.S. Geological Survey. Denver. CO. Personal Communication.
Baker, V.R. and D.F. Ritter. 1975. Competence of rivers to transport coarse
bed material, Geological Society of America Bulletin 86: 975-978 (July).
Beard, L.R. 1962. Statistical methods in hydrology. Corps of Engineers:
Sacramento.
Bevan, A. 1925. Rocky Mountain peneplains northeast of Yellowstone Park.
Journal of Geology 33: 563-87.
Blackwelder, E.T. 1915. Post-cretaceous history of the mountains of central
western Wyoming. Journal of geology 23: 97-340.
Borland, W.M. 1971.
H.W. Shen, ed.
Reservoir sedimentation.
Colorado State University:
In: River mechanics, Volume II,
Fort Collins. Pp. 29-1 to 29-38.
Chorley, R.J. and M.A. Morgan. 1962. Comparison of morphometric features,
Unaka Mtns., Tennessee and North Carolina, and Dartmoor, England. Geological
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