HomeMy WebLinkAboutSurface Water Resources and Development Inventory Yukon Region Preliminary Draft 1973·-,
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I N V E N TOR Y
Y U K 0 N REG ION
SURFACE WATER RESOURCES AND DEVELOPMENT
RESOURCE PLANNING TEAM
He JOINT FEDERAL-STATE LAND USE PLANNING COMMISSION
107
.A4
J652
1973
v.3
PRelIMINARY DRAFT
RESOURCES INVENTORY
YUKON PLANNING REGION
ARLIS
AJaska Resources
Library & Information SerVices
AnchOr::lffF "hI' 1,
SURFACE WATER
RESOURCES AND DEVELOPMENT
J. David Dorris
Resource Planning Team
Joint Federal-State Land Use Planning Commission
September 1973
H
')
,f .i
In view of the process which was utilized in preparing this
material, users are cautioned to take cognizance of the
following limitations. First, this information is primarily
an extrapolation from a literature data base which is sometimes
incomplete. Accordingly, in certain instances, additional
primary research may be required to verify conclusions reached
herein. Second, the material which follows inevitably includes
subjective interpretations of existing data by one or more
members of the Resource Planning Team. Consequently, it is
possible that other resource professionals having comparable
knowledge and expertise could reasonably come to different
conclusions. For these reasons, the Planning Commission, the
Resource Planning Team, and the respective agents, servants,
employees, members, and independent contractors of these entities
do not warrant the accuracy or completeness of the following
information or that the same can be relied upon without verification
through the use of data derived from other sources.
YUKON PLANNING REGION
TABLE OF CONTENTS
List of Tables
List of Maps
List of Water Resources Overlay Maps
Preface
Acknowledgements
Summary
I
II
III
Introduction
Yukon Planning Region
Subregions
Lower Yukon
Existing Situation
General
Streams
Distribution of Runoff
Lakes
Storage
Chemical Quality
Sediment
Page
vi
vii
1
2
3
4
8
8
9
11
11
11
14
19
19
20
20
22
..
Page
Existing Problems 23
jiWl
Flooding 23
Water Supply 27
Navigation 29
Power 32
Transmission 34
->~
Drainage 34
Irrigation 34
Recreation 35
Fish 35
Sedimentation 36
Floatplane Operation 36
Stream Pollution 37 'l'irr,
Potential for Water Resource Development 37 ...
Water Supply 37
Flood Control 38
Navigation 39
Power 39
Recreation 42
Fish 43
Wildlife 44
IV Central Yukon 46
Existing Situation 46
General 46
Streams 49
J'1'
,,..
...
v
Distribution of Runoff
Lakes
Storage
Chemical Quality
Sediment
Existing Problems
Potential for Water Resource Development
Water Supply
Flood Control
Navigation
Power
Koyukuk
Existing Situation
General
Streams
Distribution of Runoff
Lakes
Storage
Chemical Quality
Sediment
Existing Problems
Potential for Water Resource Development
Power
Page
49
50
50
50
51
53
53
54
54
56
56
62
62
62
64
64
64
64
64
64
64
66
66
""" Page
VI Upper Yukon 72 ,fj'l
Existing Situation 72
General 72
Streams 76
Distribution of Runoff 76
Lakes 76
Storage 76
Chemical Quality 76
Sedimentation 76
Existing Problems 76
Potential for Water Resource Development 76
Power 76
VII Tanana 87 "'"
Existing Situation 87
General 87
Streams 90
Distribution of Runoff 94
Lakes 100
Storage 100
Chemical Quality 101
Sedimentation 101
Existing Problems 103
Flooding 103
Water Supply 104
L ! '.;
Navigation
Drainage
Sedimentation
Ice
Permafrost
Stream Pollution
Potential for Water Resource Development
Water Supply
Flood Control
Navigation
Irrigation
Power
Recreation
Fish
Wildlife
VIII Upper Yukon -Canada
Existing Situation
General
Existing Problems
Potential for Water Resource Development
Page
105
105
106
107
108
109
110
110
111
113
115
116
124
125
125
126
126
126
126
127
• ..
List of Tables ..
Page
Table 1 Tributaries of Yukon River 16-18 ""',
Table 2 Upland Lakes, Yukon River Basin 21
' ..
Table 3 Yukon Region Summary of Alaska Lower Priced Hydro-45
electric Potentials with 2,500 kilowatts of continuous
power or larger.
Table 4 Drainage Areas and Gradients of Principal Streams 92
Table 5 Average Stream Flow 97
..
" ..
'Of
List of Maps
Page
Map 1 Regions and Subregions 1'1
Map 2 Lower Yukon Subregion 12
Map 3 Water Resources - Lower Yukon Subregion 24
Map 4 Central Yukon Subregion 47
Map 5 Water Resources -Central Yukon 55
Map 6 Koyukuk Subregion 63
Map 7 Water Resources -Koyukuk Subregion 65
Map 8 Upper Yukon Subregion 73
Map 9 Water Resources -Upper Yukon 77
Map 10 Tanana Subregion and Upper Yukon -Canada 88
Map 11 Water Resources -Tanana and Upper Yukon Canada 112
...
Water Resources Overlay Maps
Inventory Maps, Scale 1:250,000. Includes following information.
1.
2 .
Drainage boundaries of the larger rivers and tributaries.
Approximate extent of floodplains for the larger rivers.
This is based on rough interpretation of topography using
1:63,360 scale maps and is subject to substantial error.
No attempt made to show floodplains of the smaller river
system. (shaded)
3. Identified water development potentials. (9)
Includes most favorable hydropower sites (W) from state-
wide inventory and additional sites identified in the
inventory which may have value for storage and regula-
tion for various purposes (S). Also includes identi-
fied potentials for navigation improvements (N).
4. Reservoir Maps (Scale 1:250,000)
Separate maps indicating lands involved in the major
hydroelectric power projects.
I
Preface
The Yukon Planning Region is the third study of a series being
prepared as a part of the Resource Planning Team's statewide
resources inventory.
The inventory generally follows BLM "Unit Resources Analysis"
procedures. This report section is intended to cover URA Steps
3 and 4 --existing situation and potential use and development
--for water as a single resource category.
Data presented on the inventory maps and accompanying narrative
and tabulations includes: delineation of drainage basins and
selected data on the larger river and lake systems; a preliminary
indication of potential flood hazard areas along the major rivers;
and potential water developments for storage, power, and other
purposes identified in various studies.
This report section is not intended as a comprehensive appraisal
of water resources conservation and management aspects. Parallel
efforts by other team members cover much subject material that
bears on water management needs. Community, coastal zone, water
based recreation, fish and wildlife, and drainage aspects are
all covered under other resources categories.
2.
Acknowledgement
Major portions of this report have been taken verbatim from:
Harbors and Rivers in Alaska, Survey Report. Interim Report No.1
Yukon and Kuskokwim River Basins
U. S. Army Engineer District, Alaska
Corps of Engineers December 1959
Alaska Natives and the Land
Federal Field Committee for Development Planning in Alaska.
Anchorage, Alaska October 1968
Water Resources of Alaska
A. J. Feulner, J. M. Childers, and V. W. Norman
U. S. Dept. of the Interior. Geological Survey, Water Resources
Revised, Alaska District 1972
This is an unpublished document.
Data relative to hydroelectric projects has been taken from unpublished
reports of the Alaska Power Administration.
The author has taken considerable liberties with the editing, use, and
arrangement of these data. The extent of their use prohibits repeti-
tious footnotes. Errors in their use are solely those of the author.
3
Summary
The Yukon Planning Region includes the entire drainage of the
Yukon River. It stretches from the Canadian border to the Bering
Sea (See Map 1). Involved in this is some 204,000 square miles
in Alaska plus 130,000 square miles in Canada. The largest tribu-
tary drainages are the Porcupine (450,000± sq. mi.), Tanana
(44,000± sq. mi.), Koyukuk (32,400± sq. mi.), and Chanda1ar Rivers
(9,900± sq. mi.).
Stretching over 1,800 miles, the river dominated area includes such
diverse features as the Tanana uplands, the lake/marsh dotted
Yukon Flats, Rampart trough and the Yukon-Kuskokwim coastal
lowlands.
For purposes of this report the region is divided into 6 subregions
which reflect various segments of the Yukon River and its tribu-
taries. These are the Lower Yukon, Central Yukon, Koyukuk, Upper
Yukon, Tanana and Upper Yukon -Canada.
The climate varies from Maritime (part of the Lower Yukon) to
Arctic Continental (Upper Yukon) to Continental (all others).
Temperatures have a wide range with maximums and minimums of
100 0 and -76 0
• Snowfall in the lowlands may average no more than
7" while higher elevations may exceed 120". The many streams
would suggest that water is plentiful but this is an illusion.
The average annual rain varies from about 7" to 25" (on the
coast). Because of the almost universal permafrost, the
precipitation percolates to the permafrost and then runs off into
the streams. Dissolved solids and sediment loads vary with the
time of year, vegetated cover, and source of the stream (glacial
or other). Measurements of dissolved solids have varied from
30 mg/l in the Lower Yukon to nearly 500 mg/l in the Tanana.
Sediment loads as low as 10 mg/l have been recorded on nonglacial
streams and is suspected to exceed 500 mg/l in the glacial stream.
The Yukon River will vary from 150 mg/l to over 800.
The development of water resources within the area is minimal
except in the Tanana River area (Nenana, Fairbanks and the military).
Most of the river communities have problems of stream overflow and
ice jam flooding; a lack of potable water storage, treatment and
distribution; a lack of sewage disposal; navigation problems
beginning at the Bering Sea extending up the river ways; and limited
availability of power at relatively high costs.
Most of the problems are compounded by the low temperatures,
permafrost, small population, and minimal economic base.
Water resource development potentials are limited only by the
economics of the various projects and are related to the problems
of the proceeding paragraphs. These include potable water
systems and waste disposal systems for the villages; navigation,
port/dock improvements; flood control via levees, dams or
"new towns" and the provision of low cost power.
The Yukon River and its tributaries provide opportunities for
the development of nearly 18,000,000 kilowatts of installed
power in some 19 projects. These facilities would provide flood
control, navigative aids, and electric power. Detailed environ-
mental studies remain to be accomplished on most of these
projects.
Water-related Access Needs
No specific information has been developed on a regional basis.
Public access to lakes, and streams, the shoreline, and beaches
for a variety of uses will be important. Needs include recrea-
tion, fisheries harvest, harbor development, and others.
Specific items that merit attention are in connection with the
major identified development potentials including the hydroelectric
potentials.
..
...
Reference and Data Needs
The amount of water resource data available in this region is
limited. Little specific information is available outside the
more populated areas. There is little data beyond the topo-
graphic maps on which to base flood information.
Water resource planning to date is mostly of an inventory
nature. Most evaluations of potential developments rest on
very preliminary investigations including extrapolated data.
The lack of mUltipurpose plans may be the most critical infor-
mation map with respect to the current land use planning. Excepting
a few major development potentials and very preliminary indications
of flood hazard areas, the lands that may be involved in a
long range river basin plans are not identified.
7
Water Resources and Development
YUKON PLANNING REGION
Introduction
~he Yukon Planning Region includes the entire drainage of the Yukon River.
It stretches from the Canadian border to the Berinp, Sea (See Map 1).
Involved in this is some 204,000 square miles jn A1aRka plus 130,000
square miles in Canada. The 1ar~est tributary drainages are the Porcupine
(450,000± sq. mi.), Tanana (44,000! sq. mi.), Koyukuk (32,400± sq. mi.),
and Chanda1ar Rivers (9,900± sq. mi.).
Stretching over 1,800 miles, the river dominated area includes sllch
diverse features as the Tanana uplands, the lake/marsh dotted Yukon Flats,
Rampart trough and the Yukon-Kuskokwim coastal lowlands.
..
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•
.~
oil
....
...
...
. ,.
II Subregions
The six subregions of the Yukon Region reflect the various segments
of the Yukon River and its major tributaries.
Lower Yukon Subregion is the western or Bering Sea end of the
Yukon River and includes the vast delta area of the coastal
lowlands •
Central Yukon Subregion extends from below Kaltag to the confluence
of the Tanana and Yukon River, includes the river valley lying
between the Kuskokwim and Ray Mountains.
Koyukuk Subregion includes the drainage area of the Koyukuk River.
Upper Yukon Subregion includes the Yukon above the Tanana River and
the tributaries Chandalar and Porcupine.
Tanana Subregion includes the drainage of the Tanana River •
Upper Yukon-Canada includes those drainages of the Yukon River which
flow into Canada before entering the Yukon River •
9
.'''' 'J~ .... \
INDEX YAP OJ' 4L.UK4
• .
REGrOi~S AND SUBREGIO;;S
1.ARCTIC
1.1 \·Jest Arctic
1.2Colv;11e
1.3East Arctic
2 . NOR T H \.J EST
2.1 Kotzebue Sound
2.2Norton Sound
3.YUKON
3.1 Lower Yukon
3.2 Central Yukon
3.3 Koyukuk
3.4Upper Yukon
3.5 Tanana
3.6 Upper Yukon-Canada
4. SOUTH/JEST
4. 1 K us k 0 k\" i m Bay
4.2Bristol Bay
4.3Aleutian
5. SOUTH-CENTRAL
5.1 Kodiak-Shelikof
5.2 Cook Inlet
5.3Gulf of Alaska
6. SOUTHEAST
Map 1
III Lower Yukon
Existing Situation
General: The Lower Yukon Region includes all or a portion of the
following physiographic sections: Yukon-Kuskokwim Lowland, Nulato Hills,
Innoko Lowlands, and Kuskokwim MOuntains. This is all the drainage
system of the Yukon downstream from Kaltag (See Map 2).
The Yukon River flows along the base of the Nulato Hills. In combination
with the Kuskokwim River it deposits the sediments of a sub-continent
building the vast delta area into the Bering Sea. This lowland delta
is a ~ake dotted marshy plain traversed by sluggish meandering streams,
many of them distributaries or former channels of the Yukon River.
Probably 30 to 50 percent of the delta is lake surface. The larger of
these thaw lakes, many over ten miles in length, have scalloped shorelines
and probably have been formed through the coalescence of several smaller
lakes.
Across the Yukon delta there is typical tundra vegetation. Traveling
westward up the river the vegetation gradually grows more luxuriant, with
willows and alders, until spruce enter the plant community.
The climate of the region is affected primarily by the Bering Sea to the
west and the Kilbuck-Ahklun Mountain Ranges to the east and south. These
Ranges, along with the Aleutians, tend to direct some storms northeastward
into the Bering Sea and the lowland country. On such occurrences, winds
I I
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BERIlVG
5 E A 0 62 ___ _
'r 0'" USIiS •• , ( r.J~!
16S'
I--I
__ 02
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156'
loS \!1op2.
Lower Yukon
5ubr~lon
\2.
-~--.------
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I ,
•
in excess of seventy m.p.h. are not uncommon. Maximum velocities
accompany northeast winds in winter and southeast winds in summer.
During the winter, too, strong southerly winds affected by the Kilbuck
and Ahklun Ranges produce Chinook conditions, occasionally causing
50 0 temperature rises in less than 24 hour periods.
The proximity of the region with the sea, however, dominates the
mountain influences and while in the transitional zone it may be
characterized as more maritime than continental. As a result, daily
temperature extremes are modified during most of the year. But in
June to July and again in late December, and early January continental
influences are felt. Temperature extremes caused by this continental
dominance range 142 0 --from -52 0 in January to 90 0 in June.
Average temperatures, however, are more moderate than in the interior
of Alaska. The growing season lasts about 100 days and is adequate for
several crops: cabbages, potatoes, cauliflower. beets, turnips, lettuce
and carrots.
Annual precipitation averages nearly nineteen inches with an average
range of 14 to 25 inches. August is the wettest month with an average
rate just over four inches. Snowfall averages about sixty inches.
Permafrost is present throughout nearly the entire subregion except
beneath and adjacent to larger stream channels. No glaciers and only
a few snowfields occur in the subregion.
13
Streams: The officially accepted source of Yukon River is in a
glacier upstream from the head of Lendeman Lake at a point about 1,875
miles from its principal mouth. Many miles could be added to the length,
however, if a course through the large headwater lake and drainage
system, surrounding Whitehorse, were followed to the most distant source.
This upper part of the Yukon, formerly called the Lewes, collects the
discharge from an intricate drainage system in its northwesterly course
before it is joined by the large Pelly River from the east at mile 1.520.
White River enters from the west or left at mile 1,428 and Stewart River
from the east or right at mile 1,418. Klondike River joins from the ri~ht
at about mile 1,357 just above Dawson, Yukon Territory. The Yukon
continues northwesterly into Alaska at mile 1,267 and on to Fort Yukon,
mile 1,035, just north of the Arctic Circle, where the right bank
tributary, the Porcupine, enters from the east. The course of the river
there deflacts southwesterly, and follows that general direction to the
mouth of the Koyukuk River which enters from the right at mile 515. More
specifically within this reach, and after meandering across the Yukon
Flats in divided channels, the river enters Rampart Canyon at mile 805
and continues flowing in a canyon section to iust above the mouth of the
Tanana River at mile 720. At the mouth of the Koyukuk the course is
turned south by the low mountain range east of Norton Sound. The stream
continues southerly to mile 245, about 8 miles below Paimiut. From
there it turns irregularly northwest and divides into three distinct
channels, Apoon (navigation) Pass into Norton Sound, Kwikpak Pass,
and Kwikluak Pass, the latter bein~ the princinal m~uth~ tnto the Bering Sea.
..
Table I lists and provides selected data on tributaries to the-: Yukon
River. The Lower Yukon segment includes these tributaries from the river
mouth to and including the Khotol.
The flat profile threading the intricate lake system of the Upper Yukon
in Canada is succeeded by reaches of stp.epm:" gradient where the river
is closely confined. Below Dawson, the river, though c~nfined, flattens
out somewhat to the Eagle-Circle Canyon in Alaska. There the gradient,
fairly uniform except at Nation Reef below Nation River, steepens a little
with resulting fairly high velocity. Below Circle the same gradient
continues through Yukon Flats to Fort Yukon, with braided channels
threading the cobble and gravel bed. Below Fort Yukon this regimen continues
at flatter gradient across Yukon Flats to Rampart canyon, through which
the closely confined channel has a somewhat steeper though still relatively
flat gradient to the mouth of Tanana River. Below that point the gradient
flattens progressively down to Paimiut Slough then reduces to near zero.
Slopes of the Yukon River, in successive reaches, are shown in the following
tabulation.
Location
Mouth
Below Paimiut Slough
Nowitna River
Tanana River
Stevens Village
Beaver
Fort Yukon
Woodchopper Cr. Dam Site
International Boundary
Klondike R., Dawson
Stewart River
Pelly River
Foot of Lake LaBerge
Lindeman Lake
River Mile
0.0
245.
636.
720.
868.
958.
1,035.
1,149.
1,267.
1,358.
1,418.
1,520.
1,720.
1,869.
IS-
Approx. Slope Per Mile
Elev • ___ -"I-"nO-.-U~p_=:s_=:t:..::r_=e_'_a_"_m_R_=e'_"a;..;;c=h
0.0
25.
150.
200.
290.
330.
415.
645.
890.
1,035.
1,285.
1,420.
2,060.
2,182.
0.1
0.3
0.5
0.6
0.4
1.1
2.0
2.1
1.6
4.2
1.3
3.2
0.8
'-..
*
"',
TABLE 1
TRIBUTARIES OF YUKON RIVER
----_. ----_._----------------------------------------
Dra inap,e Length
Tributary At Area
River To River Mile Square Mile Miles
--.-
Andreafsky Yukon 94 1,360 105
E. Fork Andreafsky Andreafsky 5 835 122
Chui1nak Yukon 116 1,989 33
Atchueelinguk Chuilnak 34 1,447 97
Reindeer Yukon 123 329 70
Ta1biksok Yukon 205 208 56
Innoko Yukon 280 10,900 463
Reindeer Innoko 14 477 49
Iditarod Innoko 144 3,194 297
K1uk1ak1atna Innoko 283 1,172 49
North Fork Innoko Innoko 368 1,116 49
Bonasi1a Yukon 313 1,275 93
Anvik Yukon 325 1,700 126
Khotol Yukon 440 821 61
Nulato Yukon 495 866 73 ,·'tt
South Fork Nulato Nulato 4 295 57
Koyukuk Yukon 515 32 ,600 554
Giassa Koyukuk 62 566 89 '!l-..,
Kateel Koyukuk 85 1,516 114
Dulbi Koyukuk 150 1,444 132
Huslia Koyukuk 195 2,336 126
Hogatza Koyukuk 258 1,723 164 ".~~
Kanuti Koyukuk 446 2,995 93
A1atna Koyukuk 460 3,543 201
Sozhekla Koyukuk 483 626 49
South Fork Koyukuk Koyukuk 496 2,257 136
John Koyukuk 528 2,699 133
Wild Koyukuk 535 578 62
Middle Fork Koyukuk Koyukuk 554 852 68
North Fork Koyukuk Koyukuk 554 1,826 102
Yukon Yukon 575 1,574 174
Melotzitna Yukon 596 2,700 249
Little Melozitna Melozitna 201 606 72
Nowitna Yukon 637 7,200 283
Sulatna Nowitna 73 1,444 180
Little Mud Nowitna 95 485 118
Big Mud Nowitna 130 554 59
Titna Nowitna 137 1,440 100
Sulukna Nowitna 173 632 68
Susu1atna Nowitna 229 530 76
Tozitna Yukon 706 1,700 103
Tanana Yukon 720 44,500 531
Hess Creek Yukon 810 1,175 79
.• '
It-
~ -----
TABLE 1 (Cont.)
TRIBUTARIES OF YUKON RIVER
Drainage Length
Tributary At Area
River To River Mile Square Mile Miles
Beaver Creek Yukon 930 3,200 303
Hodzana Yukon 930 1,293 140
Birch Creek Yukon 1,003 3,776 314
Chanda1ar Yukon 1,013 8,180 113
Vf E. Fork Chand alar Chanda1ar 75 4,796 213
M. Fork Chand alar Chand alar 113 1,776 123
N. Fork Chand alar Chand alar 113 661 118
Christian Yukon 1,018 2,718 110
Porcupine Yukon 1,034 46,200 555
Little Black Porcupine 19 2,199 205
Black Porcupine 25 6,470 255
Sheenjek Porcupine 37 4,788 277
Co1een Porcupine 142 4,273 180
Salmon Trout Porcupine 179 840 55
Rapid Porcupine 188 571 57
Bluefish Porcupine 240 1,041 85
Old Crow Porcupine 263 4,042 160
Bell Porcupine 347 4,200 113
Woodchopper Creek Yukon 1,149 82 18
Charley Yukon 1,166 1,713 81
Kandik Yukon 1,177 1,194 112
Nation Yukon 1,210 630 60
Seventymi1e Yukon 1,237 684 64
Fortymi1e Yukon 1,306 6,562 56
N. Fork Fortymi1e Fortymi1e 56 450 47
M. Fork Fortymi1e Fortymile 56 1,100 67
Chandindu Yukon 1,336 53
Klondike Yukon 1,355 4,100 102
N. Klondike Klondike 28 530 52
Sixtymile Yukon 1,396 1,523 83
Stewart Yukon 1,416 20,500 390
McQuesten Stewart 92 640 105
Hess Stewart 240 4,860 175
Lansing Stewart 260 68
Beaver Stewart 290 82
Nada1een Stewart 297 57
White Yukon 1,427 18,500 177
Ladue White 28 1,800 75
Donjek White 68 7,313 159
Pelly Yukon 1,520 20,275 457
MacMillan Pelly 76 5,692 290
Tay Pe11y 165 260
Ross Pelly 263 2,731 177
Big Creek Yukon 1,536 718 56
Nordenskio1d Yukon 1,592 1,826 77
Little Salmon Yukon 1,625 1,340 116
Big Salmon Yukon 1,663 1,993 136
iii
17
TABLE 1 (Cont.)
TRIBUTARIES OF YUKON RIVER
Drainage
Tributary At Area
River To River Mile Square Mile
Tes1in Yukon 1.696 13,900
Nisutlin Teslin 147
Gladys Teslin 178
Swift Teslin 183
Jennings Teslin 188 3,370
Takhini Yukon 1,760 2.370
Source: Yukon and Kuskokwim River Basins, Interim Report No.7.
Harbors and Rivers in Alaska Survey Report. U. S. Army
Engineer District, Alaska, Corps of Engineers Dec. 1959.
p. 19-21.
1 ;, ," \-'\
'E
Length
}1i1es
253
150
88
88
96
105
The drainage areas at pertinent locations and the estimated average
annual flows are shown in the following tabulation:
Location
Woodchopper Creek
Rampart Canyon
Kaltag
Paimiut
Mouth
Drainage area
sq. mile
121,800
200,000
296,000
316,000
330,000
Average
Cfs
84,500
118,000
199,000
224,000
231,000
annual flow
Cfs sq. mi.
0.69
0.59
0.67
0.71
0.70
Source: Yukon and Kuskokwim River Basins, Interim Report No.7.
Harbors and Rivers in Alaska Survey Report. U. S. Army
Engineer District, Alaska, Corps of Engineers Dec. 1959.
Distribution of Runoff: The local runoff is unmeasured in this subregion.
For the region, mean annual runoff probably averages about 1 cfs per
square mile. The mean annual peak runoff of the small areas probably
averages less than 10 cfs per square mile. Ice-jam flooding during spring
breakup is probably common along the rivers. Mean annual low monthly
runoff probably averages about 0.2 to 0.3 cts per square mile and occurs
in the late winter.
Lakes: Within the report area in Alaska, there are only a few upland
lakes, some without outlet. Natural regulation of flows afforded by the
lakes is small. Neither are they favored, like the perched lakes in
Southeastern Alaska, with potential outlet dam sites permitting storage
for economic power development. However, lakes abound in the Canadian
portion of the basin and while their natural regulating effect is
considerable on the streams draining them, only a relatively small part of
)9
the tributary upper basin has natural rep,ulation. Larr,e downstream
tributaries in Yukon Territory largely nullify the effect of lake
regulation along the Upper Yukon. But this concentrated lake system,
fortunately, confined to a small elevation belt, affords Rtorage and
exceptional possibilities for potential trans-basin conveyance and
development of unusually high head and low-cost power.
The following tabulation comprises named lakes either over 10 square miles
in area, or included for demonstrated economic reasons, such as storage
for power or for float plane access to mining or recreational areas.
Storage: The main storage feature in the subrpgion i:~ the winter snow
that accumulates until spring. The amount of w;,l('r qtoTPd in t"hp
annual snowpack and the rate of melting in spring determine the extent
of spring flooding and the amount of early summer flow that will occur.
Low flow is usually the result of the winter freeze recession during
which the snowpack is forming. The longer the recession, the lower the
flow will be. The streams that drain the swamp areas probably have the
higher low-flow rates. Water storage in swamps and shallow ground water
aquifers may be important in sustaining low flows.
Chemical Quality: Chemical quality information is very limited. Only
five random quality of water sites have been sampled in the Lower Yukon
subregion: they are the Yukon River at Kaltag and at Saint Marys, the
Innoko River at Holy Cross and at Shageluk, and on Savoonga Creek near
Savoonga on Saint Lawrence Island.
,.,
Name
Kulik
Mentanontli
Wild
Chand alar
Old John
Mayo
Ethel
Wellesley
Tincup
Kluane
Tatlmain
Earn
Little Salmon
Drury
Teslin
Quiet
Wolf
Gladys
Laberge
Kusawa
Primrose
Marsh
Tagish
Tutshi
Bennett
Homan
Lindeman
Graham Inlet
Surprise
Atlin
Little Atlin
Dimensions
Length Av. Width
Miles Miles
4.3
3.6
6.1
8.5
5.5
21.
12.5
9.
9.5
38.
13.
13.
21.
15.5
79.
19.5
14.5
20.
30.
49.
13.
22.
67.
23.
26.
4.5
5.
19.
16.5
72.
13.5
2.4
2.4
0.8
1.5
1.7
1.5
1.5
3.
1.
3.
1.
0.7
1.
0.7
2.
1.
2.
1.5
2.5
1.
0.5
2.
1.5
1.
1.
0.5
0.5
0.9
0.7
3.
1.2
~:
TABLE 2
UPLAND LAKES
Yukon River Basin
Area
Sq.
Mile
10
9
5
10
9
36
18
29
8
166
14
12
24
11
142
21
28
28
80
54
5
39
122
21
37
2
2
16
12
231
16
Elev.
Feet
M.S.L.
2,203
2,505
2.045
2,680
2,561
1,829
2,078
1,995
2,360
2,239
2,630
3,250
2,915
2,060
2,200
3,150
2,149
2,152
2,320
2,153
2,645
2,180
2,152
2,985
2,197
2,253
Outlet
Talbiksok R. -Yukon R. Mile 204
Mentanontli R. -Kanuti R. -Koyukuk R.
Wild R. -Koyukuk R.
N. F. Chandalar R. -Chandalar R.
Koness R. -Sheenjek R.
Mayo R. -Stewart R.
Nogold Cr. -Stewart R.
Wellesley Cr. -Donjek R. -White R.
Tincup Cr. -Kluane R. -Donjek R. -White R.
Kluane R. -Donjek R. -White R.
Mica Cr. -Pelly R.
Earn R. -Pelly R.
Little Salmon R.
Drury Cr. -Little Salmon R.
Teslin R.
Unnamed -Nisutlin R. -Teslin·L.
Wolf R. -Nisutlin R. -Teslin L.
Gladys R. -Teslin L.
Yukon R.
Takhini R.
Primrose R. -Takhini R.
Yukon R.
Yukon R.
Unnamed -Taku Arm (Tagish L.)
Yukon R.
Homan R. -Bennett L.
Yukon R.
Taku Arm -Tagish L.
Pine Cr. -Atlin L. -Atlin R.
Atlin R. -Graham Inlet (Tagish L.)
Lubbock R. -Atlin L.
-----------------------_._-._._------------------.--_._--_._---------_._-----
Source: Yukon and Kuskokwim River Basins, Interim Report No.7.
Harbors and Rivers in Alaska Survey Report. U. S. Army
Engineer District, Alaska, Corps of Engineers Dec. 1959 p. 23A.
The observed range in the dissolved solids content of the surface
water is from 39 mg/l at Savoonga Creek to 139 rnr,/l on the Innoko
River near Holy Cross. All sampled surface water was of the calcium
bicarbonate type and was of acceptable quality, exceeding the U. S.
Public Health suggested limits only in iron content.
Sediment: Most streams in the subregion, except the Yukon River,
probably carry less than 100 mg/l of suspended sediment during
most of the summer.
The streams on the Yukon River delta probably carry much organic
material derived from the swamps and bogs. It is unlikely that
more than 1% or 2% of the suspended sediment would be coarser than
0.062 mm.
During flood stages the Yukon as well as some of the tributaries,
carry considerable silt in suspension. However, observed mainstream
sediment quantities are comparatively small. Quantitive analyses
of water samples taken at various places, times, and stages have
yielded results in striking contrast with appearance. Some of the
headwater tributary streams carry a perceptible silt and bedload
so that the Yukon has a characteristic dark yellow color. Samples
taken from the Yukon in June, from the surface down to 0.6 feet from
river bottom, yielded a maximum dissolved and suspended load of
•
•
800 mgtl •. At other times, the summer load has shown a pronounced
drop to 150 mgtl. At lower stages, the river bottom in Rampart
Canyon is clearly visible from boats. The maximum mainstream
water temperature is about 60 0 F.
No bedload data are available nor have particle size determinations
been made of the sediment transported. There are reaches like Yukon
Flats with rather steep gradient where during high stages, the move-
ment of bedload gravel and boulders is enough to shift navigation
channels.
Existing Problems: Numerous water related problems existing along
the entire reach of the Yukon River. These will be covered under
various headings.
F!ooq1ng: Mainstream Yukon River floods comes with the annual spring
snowmelt. Basin wide rains are too light and summer storms are too
localized for regional effect. Furthermore, the exceptionally
light spring precipitation does not significantly affect flood stages.
On the river and on its tributaries, the spring flood stages are
higher after winters of heavy snowfall, especially if abnormally high
temperatures occur.
More often than not, mainstream flooding at this time is aggravated
by ice jams, not only causing inundation over banks above such jams,
o
C:-~A4llfS
Floodio9
Point is of unknown bLAt
Wicluprcad Exte.nt ---
B E R 1 N G
SEA
~~ USGS ~I~ ( base ,.--
1 0
\ 60 0
I
\ --r---
_-EZ'
, \
y' kon -KuskokwIm .
Na i9atio" Enhancement Facility
\
\
\5S O
Mop 3, .
15 s'
SURFACE WATER RE!.OURCE
Pat~"hal Flood,n; an~ Wal .. 0. ... 10 ........
Opportunitle'
o
-/3
'"--
Pol"'~lol Flaodill9
Po,...,I,al Wa' .. Stc.,. S,le
Po'''''',ol Hydrael.clTic Si ..
Potential Conal ~ile
,---1 __ 2.4,. "--'
but downstream when they suddenly give way. Such flooding prevailed
regionally on the Yukon in the spring of 1945 when Galena village
was under seven feet of water. Circle City and Fort Yukon have often
suffered. On the Yukon, the spring thaw in Canadian headwaters inland
from the Gulf of Alaska may start well ahead of its beginning at
Fort Yukon, far down river, and in colder latitude 500 miles north,
thus setting the stage for particularly severe ice jams that may
override banks and crush buildings. The main stream-floods are flat
crested, and stages remain at or near the peak for a period of from
several days to more than a week. Flow patterns of snowmelt floods
closely reflect temperature variations. Except on tributaries,
fluctuations due to night frosts are rare.
Such periods of high water may coincide with the ,peak of the navigation
season and may delay shippin~ for a period when every day is necessary
to get supplies in for the lon~ closed season. Major floods cause
delays and inconvenience to navigation by high velocity flow, and in
places, inundation of the usual docking facilities.
Thus floods tend to disrupt transportation to large areas whenever
the river communities become inundated. Damage caused by floods under
the present state of development is minor if evaluated monetarily.
In terms of losses to those flooded, the damages are significant, and
the periodic flooding acts as a deterrent in development.
Many communities in the Yukon River Basin, notably, Galena and Fort
Yukon, are periodically flooded. Warm interior weather after winters
of heavy snow resulted in unusually high sta~es durin!", the sprin~ of
1957. Such high stages accompanied by ice iams caused the most
widespread damage in many years. The ensuing monetary damage is not
sufficient to warrant large flood control works at this time to
alleviate the problem. Local protective works at some of the more
critical locations, however, have been considered to reduce the losses
suffered by some communities. Improvements designed to assist in
developing the vast area covered in this report, such as a land
transportation system, will be made more expensive because of the need
to incorporate flood protective works as a part of their construction.
One common factor of the flood problem affects many of the communities
of the report area. The higher stages of the rivers that prevail
during the open season promote active bank cutting. Since many of
the communities were built along the rivers to be readily accessible
to the main arteries of commerce, most of their improvements and
service facilities have developed acljacent to the riverbank. Thus,
any extensive erosion threatens the very existence of some towns
or villages.
Galena has been inundated by flood waters from the Yukon River at
least once since establishment of a military installation there and
floods are a yearly possibilitv. A levee system was constructed as part
,,.
of the installation and has provided adequate flood protection since
built, but stabilization of the riverbank to maintain the levee system
is the greatest need at present. The military installation has been
threatened by bank erosion. The problem is intensified by the presence
of permafrost. Local protective works designed to prevent further
encroachment of the river may be the most practical solution of the
problem.
Most communities in the report area are subject to flood damage. The
annual losses at present warrant few protective works. Unforeseen
developments at any of the communities within the two basins may
necessitate local protective works at any time in the future. Major
multiple purpose projects such as storage dams would be of immeasurable
value in reducing stages, but the monetary gains foreseeable from
such reductions while a consideration would not be a great factor in
justifying storage reservoirs.
Water Supply: Most settlements in the region are located beside
rivers and the water supply is usually taken just upstream from the
villages. Given time, most of the silt settles out. Other towns and
villages take their water from tributaries. A drainage area of 300 to
400 square miles is usually sufficient to sustain continuous flow.
For winter use, ice is cut from rivers, lakes, or ponds and is either
stored in a permafrost cellar or stacked on the ground at a convenient
location. In the majority of homes, ice is melted by placing it in a
a, ..
barrel in the heated house and leaving it there to melt and be used
later. In many cases water is not boiled before use.
Annual precipitation is very small in many areas and cistern water
supplies are usually inadequate. Water which percolates down into
the gound collects in the soil at the top of the permafrost table.
Many shallow wells draw water from this stratum. Such shallow
'"
sources are not dependable. At several places in interior Alaska
deep wells which draw water from below the permafrost have been
developed. The majority of deep wells drilled in the Fairbanks area
have produced water with a relatively high iron content. However,
subpermafrost water sources appe~r to be the most dependable sources
of ground water supply.
Low temperature conditions appear conducive to prolongation of the
life of pathogenic bacteria. These same conditions promote careless
disposal of sewage and other wastes and foster the indiscriminate use
of possibly contaminated surface and shallow ground waters. Reported
cases of typhoid fever and bacillarv dysentery show that filth borne
diseases occur in significant amounts. But continued immunity in
some places is doubtless responsible for considerable carelessness in
the disposal of sewage and other wastes, along with the tendency to
use possible contaminated surface and shallow ground water.
."
The development of a safe domestic water supply for the communities
of the Yukon-Kuskokwim area presents a problem only because of the
cost involved in providing the required facilities. An adequate
supply may be obtained by most communities from adjoining streams,
but such water should be treated to remove sediment and destroy
bacteria. Permafrost complicates distributi(m of water and design
of water supply structures, but distribulion matns placed in heated
conduits called utilidors provide a positive means for maintaining
continuous service. The expense connected with such treatment and
distribution is in excess of the ability of the small communities
to bear.
Navigation: The Yukon River system supplies the principal transpor-
tation arteries for the heavy goods of commerce within the report
area. The waterways form the only surface routes of supply to much
of the area. Notwithstanding the dependence upon water transport.
the hazards to traffic are many and the difficulties vexing.
The Yukon empties into Bering Sea which is an ice bound body of water
for much of the year. Norton Sound through which traffic passes to
reach the Yukon is open from early June until the middle of October.
The shortness of the season is but one of the difficulties. Weather
presents a hazard in Bering Sea. During the navigation season it is
generally bad and changeable. Late spring and summer fogs and rain
are common. Winds shift frequently and rapidly. By early fall fogs
occur less often but the frequency of occurrence of gales increases
and snow is likely any time after mid-September.
As if bad weather and a short season do not offer enough difficulties,
extensive shoal areas extend out into Bering Sea from the land areas.
The sea itself is generally shallow, and the silt laden streams
flowing into the sea has deposited immense quantities of material at
their mouths. Such a condition is most noticeable at the mouths of
of the Yukon and Kuskokwim Rivers. The several hundreds of miles of
coastline between the mouths of the two rivers resembles a vast delta.
Material carried into the sea drifts with currents following the
coast, is deposited in bars extending many miles from the main-
land.
The Bering Sea has been only partially surveyed; although, knowledge
of the area is being extended rapidly by the Coast and Geodetic Survey
as work on hydrographic surveys, topop.raphic surveys, magnetic observations,
tides, and currents is expanded. Navigation aids are few and port
facilities are limited. The limited amount of traffic now moving into
the area mav not warrant provision of normal aids and service to
shipping. Cargo is usually lightered from vessels anchored offshore.
St. Michael, on the east point of St. Michael Island, is the point of
transfer from deep water vessels to the Yukon River boats. All service
is undertaken by the carriers under operatin?-circumstances, which
demands a know how. Due to the shoals at the mouth in Pastol Bay,
entering or departing to and from St. Michael and the Yukon River must
•
..
be undertaken at greater than average flood tides. The Apoon Mouth
entrance to Yukon River is about two feet deep at mean lower low
water and the higher tidal range about four feet above that plane.
That depth restricts vessels to river craft that may operate in such
shallow water. There are many days during the season of navigation
when it is impossible to get in or out of the river as storms are
prevalent and tides may be missed because 01 the weather. Other
mouths of the Yukon River are reported to have depths of 20 feet or
better, but many miles of open sea of the shallow waters of Norton
Sound would have to be crossed to reach any of the other mouths from
a port offering some protection for cargo vessels.
Upon the Yukon River, controlling depth to Stevens Village is seven
feet which occurs at about river mile 670. Above there, depths decrease
to between three and five feet to Fort Yukon. Depths on the Yukon are
not the principal difficulty. The short navigation season and the
relatively small amount of cargo handled presently presents the greatest
deterrent to lower cost movement of freight.
Difficulties encountered in navigating the Yukon River itself are not
the most adverse influences in the movement of commerce on the inland
waterways system. Many of the problems and much of the costs arise
from conditions on Tanana River, where the major part of the commerce
on the Yukon enters the system. Adverse conditions and restrictions from
that river have significant influence on traffic patterns and costs on the
remainder of the Yukon systems. A detailed description of the problems
encountered on the Tanana River appears in a subsequent section of this
report.
The restrictions on Tanana River limit the size of craft using the
waterway system. The relatively short distance traveled on the
Tanana permit vessels and craft to load to about one half capacity
and transfer the cargo from two carriers to one after reaching the
Yukon for the trip up or down the Yukon.
In developing the large hydroelectric sites in the area, provision
would be made to transfer river transported cargo past the high
structures. Heavy and bulky cargos are almost entirely dependent
upon the river systems. Features must be incorporated in any structures
blocking navigation to either pass the traffic or by other means
transfer cargo below the structure to above without increasing the cost
to the carriers.
Power: It is paradoxical that in this area of such high hydroelectric
potential, sufficient electric power to supply essential services is
lacking. What power is available comes from expensive sources--nearly
all diesel driven generators. Adding to the cost of operation is the
high cost of fuel. All fuel is imported and a year's supply must be
brought in during the short shipping season. Each customer has to have
adequate storage for the fuel needed until the next shipping season.
All such adverse factors add to the cost of generation.
••
-
Further contributin~ to the high cost of power is the wide dispersal
of small load centers in the area. The vast distances and present
small loads make complete integration impractical; however, with
greatly expanded loads, the majority of areas could be inteRrated into
a system which furnished low cost power. Thus, while development of
central sources of supply, at a greatly reduced cost for generation.
would benefit most areas. complete integration of all outlying load
centers does not appear feasible.
The high cost of electric power retards the demand for expansion
of power generating facilities. Also, the small loads do not offer
an inducement to provide more efficient generation which would permit
a reduction in the rates. As a consequence. only the more essential
needs are served, and the installed generation at anyone location is
barely adequate to supply the most essential demand. Any industrial
development must plan on providinp, its power supply as well as other
facilities which necessarily adds to the cost of production.
The area covered in this report contains large and highly attractive
hydroelectric power potentials. Studies indicate that some potential
sites would provide very low cost power. At such time as some of the
large developments are constructed making transmission feasible, some
of the communities of the area may be furnished an adequate supply of
power at relatively low cost. Such a condition would be beneficial
in furthering industrial development especially in the mineral field.
33
Transmission: To date an integrated electric power transmission
system is impractical for the small loads in the report area. Should
any of the large hydroelectric potential of the report area be
developed, transmission to distant load centers undoubtedly would be
required. No particular problems are expected in transmitting power
except for the distances involved. It is expected that transmission
would be to tidewater areas that are open to shipping the year around.
The major hydroelectric potential is at sites 300 and 400 miles
from tidewater areas that have year around shipping. Transmission
over such distances would necessitate the most advanced design of
extremely high voltage equipment of efficient transmitting characteristics.
This would keep costs at the lowest practical amount. Terrain or
climate offers no unprecedented problems.
Drainage: Large areas along the lower Yukon River have poor drainage.
Stream slopes are flat and the area lies in the permafrost belt. Only
the top layer of the soil thaws annually; consequently there is very
little percolation. As a result soils are water logged. But very
little of the large expanse of well drained land is in use, so consi-
deration of drainage seems to lie well in the future.
Irrigation: In most of the report area agricultural development is
either impractical or very limited. Obstacles include climate, shallow
soils, low temperature of the soil a few inches beneath the surface,
poor drainage, permafrost, and lack of local markets. Agriculture is
presently confined to the cultivation of hardy vegetables grown in horne
•
•
-
"'
gardens for family use. With very little land in the report area
under cultivation, the portion needing irrigation would be even smaller.
Irrigation might be beneficial in overcoming the effects of spring
and summer droughts. It might also lengthen the effective growing
season by inducing earlier seed germination and speeding growth.
However, for the present, at least, any consideration given to irrigation
for the development of agriculture will be of minor importance. Future
consideration for those areas where a limited agricultural development
appears possible will require a thorough determination before the
feasibility of extensive irrigation can be established.
Recreation: For some time, the recreation and tourist industry has
appeared to offer one of the best prospects for business expansion
within the area, but development has been slow, and for several reasons
the population of the area is small and widely scattered. The cost
of almost everything is high. Capital, labor, and building materials
have until recently found more profitable uses outside the recreation
industry. Access to most places in the basins is limted to air travel
and many attractions are not generally known about.
Fish: Problems vitally concerned with the fisheries of the Yukon and
Kuskokwim Rivers date back to 1918 shortly after the first commercial
cannery was established in the Yukon River delta. Commercial exploitations
of the salmon runs, was soon believed by Native residents and many settlers
alike, to be an infringement upon the proprietary of the inhabitants of
the region. Although concerted action of local inception failed in these
streams, it did result in the promu1~ation of regulations which corrected
deficiencies related to conservation and established management and
enforcement policies, which have been in force ever since.
Sedimentation: Heavy sediment loads are carried by many of the streams
in the Yukon-Kuskokwim River Basins. The 1i~ht vegetative cover permits
active erosion to feed silt into the streams. Along the larger streams
permafrost is the least extensive, and the banks are constantly under
attack adding to the burden. The major problems arising from the large
silt loads are unstable navigation channels and storage reservations
that must be planned for any contemplated reservoirs. Planned reservoirs
are considered to have ample dead storage capacity for sediment far
beyond assumed project life. However, development of the water resource
of any stream would necessitate a special study of the sediment problem.
Floatplane Operation: The widespread use of seaplanes and pontoon
equipped aircraft is generally due to the lack of land transportation
and adequate landing fields in the coastal and inland regions. Tidal
estuaries and lakes provide the greater portion of floatp1ane landing
ways, but many large streams are also used for runways during summer
and winter operation. Restrictions imposed upon operation of f1oatp1anes
are prinCipally confined to unfavorable tidal stages and low water
stages of streams. However, within the report area are several places
where special hazards restricting operation may eventually require
consideration of remedial measures. A minor natural obstruction in the
river channel may allow landings to be made only at a point some distance
·r
-
from a village. In some coastal localities, landings can be made
only when a combination of favorable flying weather and tidal stages
permit. At these and other localities, there is a need for air
navigation improvements by deepening channels, snagging, clearing,
and removal of obstructions to alleviate the hazards of floatplane
operation.
Stream Pollution: Pollution of the surface waters of the Yukon River
system is not a problem. The communities are small and widely spaced,
and there is no industrial development, therefore, comparatively
minor amounts of waste reach the streams. The large flows available
adequately dilute any polluting material. However, in many communities,
the careless disposal of sewage and other wastes create serious local
health hazards.
Potential for Water Resource Development
Water Supply: Water development is mainly limited to Native villages
and military installations. Many of the smaller communities have
one well to supply the school and some have a second community or
village well. Most water used, however, is taken directly from surface
water sources during both the summer and winter.
Surface water offers the greatest potential for development. The flow
of the Yukon River at Kaltag, where it enters the area, is roughly
equivalent to 20 million gpm l at low flow and approaches 500 million gpm
lGallons per minute
37
at peak flow. Lake!'! that cover almost 40 to 50 percent of the southern
part of the area also offer opportunities for local water development. No
use is presently made of this water. Ground water supplies have been
generally less than 100 grm because of the fine ~rained deltaic deposits
that make up the aquifers, however, this figure iF based on present
use. Much of the ground water is high in iron or nitrate content.
Surface water although low in iron definitely is likely to be silty
during peak runoff months. However, infiltration galleries adjacent to
the streams should produce large quantities (more than 1,000 gpm) of
clear. relatively iron free water. No such galleries are known to be
in use, however.
The development of a reliable potable water supply and distribution
system is needed by most villages. Its concomitant of sewap,e collection
and disposal will become even more important with increasinp, population.
Several potential water storage sites have been identified in the area.
These are shown on the 1:250,000 and E scale maps. See reports
the Alaska District Corps of Engineers indicates that many of the
villages along the Yukon are sub;ect to some degree of flooding. Ice
jams and stream overflow appears to be the major cause of flooding with
erosion of the riverbanks a secondary problem.
ISummary of Water Supplies at Alaska Communities, Yukon Region.
July 1973. Alvin Feulner, Resource Planning Team, Joint Federal-
State Land Use Planning Commission.
'~'.
At least three alternatives are available to assist in protection
of life and property.
1) development of "new towns" outside the flood plain,
2) local protection work, such as levees and bank stabilization aid,and
3) control of the flow of the river (13) via dams and impoundments.
Numbers 2) and 3) are difficult to justify on economic grounds. Number 3)
will be further discussed under Power.
Navigation: Improvements could include dredp,ing, bank stabilization,
removal of obstacles, navigation aids, improved pert/dock facilities,
and control of the water level.
Power: Several sites in this region have been identified as having
potential for major hydropower production and flood control. Two,
Holy Cross and Kaltag, are within the subregion. The Holy Cross
site is a downstream storage potential on the main stem of the Yukon River
that could develop the power potential below the Ruby Project. (See
Central Yukon Subregion in this report). The damsite is immediately
upstream from the village of Holy Cross. In addition to developing a
large block of power, the project could provide navigation and flood
control benefits to the lower 280 miles of the Yukon River.
The studies of the Holy Cross Project to date have been largely limited
to considerations of the project as a single purpose hydroelectric
development operating in conjunction with full upstream regulation provided
by Rampart (See Upper Yukon Subregion), or a combination of projects such
as Woodchopper, Ruby, and Porcupine (See Upper Yukon).
The 320,000 square mile drainage basin tributary to the Holy Cross
damsite has an annual runoff of 160 million acre feet at the site.
The total storage capacity of Holy Cross reservoir to elevation 137
would be 140 million acre feet, which is less than the annual flow,
emphasizing the importance of upstream regulation for this
very large flow.
The attached summary tabulation of Alaska hydroelectric potentials
presents pertinent data concerning the Holy Cross Project. It
also presents data concerning the upstream Rampart, Porcupine,
Woodchopper and Ruby hydrolelectric potentials.
The plan envisioned would have an earthfill dam, with a crest length
of 57,500 feet, to form a reservoir with maximum regulated water
surface at elevation 137. The reservoir would extend 280 miles up
the Yukon River to the Ruby site, have an area of 6,600 square
miles, and a shoreline of 1,400 miles.
The Holy Cross Project would have an annual average energy production
of 12.3 hil1ion kilowatt hours, with installed capacity of 2.8
million kilowatts at 50 percent plant factor. This is almost one
third the capability of Rampart.
Holy Cross Project is an identified major water resource development
potential. There are no active proposals to construct it, and
studies to date relate primarily to establishing the resource values
involved.
40
'.
Timing and scale of development depend on long-range patterns of
development in the Yukon basin. The project appears to have
possible merit as a long-range development following construction
of upstream storage on the Yukon.
The project would result in lower flood stages and increase winter
flows below the damsite. A reduction il~ ice jam problems would
be anticipated as a result of stabilized flows. Approximately
1,200 persons would require relocation.
The potential Kaltag Project is eight miles downstream from the
village of Kaltag and about 60 miles downstream from the Koyukuk
River. It is considered as an alternative to the Holy Cross-Ruby
Project (See Central Yukon Subregion), combination to develop
storage and power potential of the Yukon River below the Rampart
site.
Studies to date, consisting of reconnaissance grade evaluations
of the project as a single purpose hydroelectric development, are
summarized in the 1965 Department of the Interior Field Report,
"Rampart Project, Alaska Market for Power and Effect of Project
on Natural Resources".
An earthfill dam with a maximum height above streambed of 180 feet,
and a crest length of 26,000 feet, would back water 250 miles up river.
The reservoir at maximum surface elevation 220 would have a surface
area of 5,200 square miles, a total storage capacity of 190,000,000
acre feet, and a shoreline length of 1,830 miles.
4/
Drainage area tributary to the damsite is about 296,000 square miles.
Project water supply has been estimated at 137,000,000 acre feet
based upon streamflow records at the village of Kaltag.
The project could produce about 13.1 billion kilowatt hours of firm
energy per year. Installed capacity would be 3,000,000 kilowatts,
assuming a 50 percent plant factor.
Recreation: The Yukon River Basin contains many fine recreational
attractions. Foremost among the natural attractions are overwhelming
grandeur of the mountains and rivers, and the seemingly endless forests
and tundra lands. Interest in the Alaska Natives and the frontier way
of life draws many visitors to the Interior. Sightseeing, camping,
fishing and hunting are the principal activities. Several widely
separated Native Indian and Eskimo villages are focal points of interest
for tourists. Transportation is by scheduled flights or conducted tours
by airlines and generally emanates from Fairbanks, and Anchorage. In
a few places, accommodations are furnished or arranged for by the
airlines. Each summer many tourists drive the two branch highways that
penetrate the basin to the upper Yukon River; the terminus at Circle
City adds attraction as the farthest north point reached by continuous
highway on the North American Continent.
Alaska attracts a large part of its touring population from many regions
of the continent. Improvement of highways leading to and through the
State to provide expedient summer travel could attract many more summer
visitors who cannot afford family travel otherwise. However, the greatest
•
necessity for improvements is the expansion and development of additional
campgrounds, trailer parks, and lodging to ease overcrowding.
As the recreation and tourist industry continues to grow in Alaska,
the great interior region will attract an increasing number of visitors.
As highways are extended in the Yukon and Kuskokwim Basins, facilities
will be needed to serve tourists and sportsmen. With continuing population
growth in the United States and resultant pressures and restrictions
accompanying the growth, the primitive regions of interior Alaska will
assume increasing recreational importance.
Fish: The Yukon and Kuskokwim Rivers are principal arteries for the
anadromous species migrating to upstream spawning grounds, and although
not of major commercial fishing significance, these streams and their
tributaries are of major importance to the people of the basins. Most
of the Eskimo and Indian people depend on fish as their basic source
of food. Special consideration will have to be given to these fisheries
in planning water use improvement programs and passageways provided
where such improvements might impede or block fish migration. Requirements
such as snagging and clearing of tributary streams to provide adequate
spawning beds lost by inundation from the construction of water storage
reservoirs and the reestablishment of anadromous fish runs may become
major considerations to be coordinated with the U. S. Fish and Wildlife
Service and other related agencies.
Wildlife: Here, as in most remote regions, particualarly in the north,
regional wildlife has always been an important part of the Native
economy, originally entirely at subsistence level, then gradually modified
since the advance of civilization. Food, clothing, and sometimes shelter
were supplied by the many species of large and small game and fur-
bering animals and from waterfowl and upland game birds. From the time
of the Russian occupation, furs have paid for things needed from the
outside world. With the decline in the fur trade, regional military
construction and incidental service occupations have supplemented Native
income in many places, but without appreciable less dependence on
wildlife for subsistence.
The construction of possible future water utilization projects on major
streams would unquestionably affect the wildlife regimen. The extent
of displacement resulting from inundation of grazing lands and loss of
habitat, and nesting grounds is not completely determined. Upland game
animals and game birds will be affected less by displacement than by
the increased hunting pressure sure to follow the very certain influx
of population with river development that will step up the regional
economy. Furthermore, improved access to the wildlife habitat will
further stimulate hunting and recreation by sportsmen who spend large
sums for transportation,. food, shelter, and guides during their annual
hunting expeditions to the interior. Further examination by the U. S.
Fish and Wildlife Service and coordination of investigation work by this
and other interested bodies would be required.
).1/ Project
Name
;TERIOR
) . Holy Cross
7. Dulbi
~ . Hughes
I . Kanuti
) . Nelozitna
L. Ruby
! . Junction Island
L Bruskasna
•• Carlo
; . Healy (Slagle)
; • ..t::,BigDelta
r~ Gerstle
I. Johnson , . Cathedral Bluffs
) . Rampart
L. Porcupine (Campbell
River)
! . Woodchopper
I. Fortymile
I. Yukon-Taiya
r
Stream
Yukon R.
Koyukuk R.
Koyukuk R.
Koyukuk R.
Melozitna R.
Yukon R.
Tanana R.
Nenana R.
Nenana R.
Nenana R.
Tanana R.
Tanana R.
Tanana R.
Tanana R.
Yukon R.
Porcupine R.
Yukon R.
Fortymile R.
Yukon R.
,Numbers used in the Statewide inventory.
Table 3
Yukon Region
SUMMARY OF ALASKA LOWER PRICED
HYDROELECTRIC POTENTIALS
with 2500 kw of Continuous Power or Larger
Drainage
Area
(sq. mi.)
320,000
25,700
18,700
18,000
2,659
256,000
42,500
650
1,190
1,900
15,300
10,700
10,450
8,550
200,000
23,400
122,000
6,060
25,700
Maximum Regulated
Water Surface
Elevation (ft.)
137
225
320
500
550
210
400
2,330
1~900
1,700
1,100
1,290
1,470
1,650
665
975
1,020
1,550
2,200
Active
Storage
(1,000 A/F)
2/
22,200
2/
13,800
1,800
2/
29,000
840
53
310
6,450
'1:../
5,300
4,900
142,000
9,000
39,000
1,610
21,000
,Reservoir held essentially full for operation with upstream plants.
,Operated in conjunction with downstream storage.
,Di\'ision of Yukon -Taiya flow from Yukon River would reduce continuous power at downstream 8ite~
,Installed at 50% load factor.
, t3sed on 75% load factor.
Dollars per installed kilowatt hour at 1965 price levels.
Percent
Stream
Regulation
100
100
91
100
83
98
97
100
100
100
1001/
84
100
Power
Continuous Insta11e~/
(1000 kw)
1,400 2,800
122 244
55 110
184 368
32 64
730 1,460
266 532
( 40)
96 ( 30)
(130)
113 226
50 100
105 210
79 158
3,904 S,040Y
265 530
1,620 2,160Y
83 166
2,400!!.l 3,20oi/
Construe
Costl
800
1,400
1,000
1,200
1,100
400
1,500
1,000
1,600
1,600
1,600
1,500
200-400
500
500
800
300
IV Central Yukon
Existing Situation
General: The Central Yukon Subregion includes all or a portion of the
following physio~raphic divisions of Alaska: Nulato Hills, Koyukuk
Flats, Tozitna-Helozitna Lowland, Nowitna Lowland, Kokrine-Hodzana
Highlands, Kanuti Flats and Indian River Upland.
Extending from the Rampart Trough to Kaltag the area is drained by the
Yukon River and its tributaries, the Nulato, Nowitna, Melozitna and
Tozitna Rivers. The Yukon flows more or less west-southwest along
the base of the Kokrine Hills, across the southern end of the Koyukuk
Lowlands until it is turned south by the Nulato Hills.
The Central and Upper Yukon Subregion includes all the drainage system
of the Yukon River upstream from Kaltag except the basin 6f the
Tanana River. The climate of nearly the entire area is Continental.
Temperature extremes of -76 0 F to 1000 F have been recorded. Avera~e
mean annual temperatures are 20 0 F to 22 0 F. Precipitation on the
lowlands averages about seventy inches of rain in summer and about seven
inches of snow in winter. Depth of precipitation in the mountains
has not been measured but is estimated to be 20 to 40 inches per year
on the basis of runoff data.
Nearlv the entire area is underlain by permafrost. However, thawed
zones that are capable of producing large quantities of ground water
'.
.....
158 •
64°------_____ -------~_t~~--~,-----~~~--~~~-------r--------
~!C~ us's •• , l tlSI
'.
Map4
Centrol
Yukon
Subre(j'on
47
are inunediately adjacent to and beneath the Yukon River and the larger
streams joining it. Alluvial and glacial deposits fill these river
basins to depths of generally less than 200 feet overlying thick deposits
of fine grained early Quaternary silt. Mountains that surround the
area are generally low, contain nearly continuous permafrost, so that
except for a few springs, the bedrock yields little water.
At Galena, centrally located in the region on the Yukon River, periods
of intense cold characterizing the Alaska interior are not quite as
prolonged or extreme as in central and eastern parts of the state.
This central Yukon area is less protected from the severe storms that
strike the Bering Sea coastal areas than is the Koyukuk basin to the
north. and thus, these storms as they approach Galena are only slightly
moderated. Most frequent in the middle and late winter months, they
are caused when high pressure areas to the east and south route Aleutian
Lows into the Bering Sea away from their usual path into the Gulf of
Alaska. Snow. high winds and considerable drifting occur with these
cyclonic passages. Another winter phenomenon is ice fog, especially
frequent in the morning hours.
About the second or third week in May, the Yukon River ice breaks up
and a typical ice jam flood hazard often results.
Throughout the Lower Yukon Region, the growing seaSOn averages 95 to
100 days.
Streams: See discussion of the Lower Yukon.
Distribution of Runoff
Runoff characteristics of streams in the interior portions of the report
area, as elsewhere in central and northern Alaska. differ greatly from
those commonly encountered in Alaska near the coast and in the other
states. The relatively short summers concentrate the major portion of
the annual runoff into less than five months. High flows occur in the
sunnner months, May through September; low flows during the winter months,
October through April. Beginning in late Sep'tember, freezing weather
at the head of tributaries rapidly advances downstream, and flow is
gradually reduced to the contribution of ground water which, in turn,
diminishes steadily to practically nothing by April. In May, the ice
in the rivers is broken up by the hi,gher flows swollen by the runoff
from snowmelt. On the larger streams, the peak flow for the year usually
occurs within one or two weeks of the breakup. Throughout the rest
of the summer, rains usually sustain a relatively high discharge. On
the larger stream~ flow may be classified three ways: minimum for winter,
maximum for snowmelt flood, and average during the open water season
for late summer flow, when the variable discharge on the smaller tributaries,
in response to local storms, and to the temperature changes, is largely
ironed out. Peak discharges from snowmelt occur almost universally
throughout the basin following the break upof the ice. Smaller peaks
sometimes occur in late summer from the heavy precipitation of a large
storm, particularly where permafrost. almost universally present
except on bare rock, be~ins near the surface and effectively ,-
prevents infiltration.
Little is known about the runoff rates although undoubtedly it
varies considerably depending mostly on topography. Mean annual
runoff probably averages from 0.5 cfs per square mile in the
lowlands to over 2 cfs per square mile on the Brooks Ranpe uplands.
The variability of annual runoff may be comparable to that of
the Chena River at Fairbanks ~lich is also in the continental
climatic zone.
Hean annual peak runoff probably averages from under 10 cfs per
square mile in the lowlands to about 50 cfs rer square mile in the
uplands. Annual peaks are caused by spring snowmelt and summer
rainfall. Stream channel icinr, is common.
Mean annual low monthly runoff probably averages close to zero.
The long cold winters cause six or more months of stream flow
recession or cessation.
Lakes: See discussion of the Lower Yukon.
Storage: See discussion of the Lower Yukon.
Chemical Quality: The chemical content of stream waters in the Yukon
basin is generally moderate to low. The limited data indicate that most
conmonly surface water is of the calcium bicarbonate type. Samples ...
analyzed have shown a range in dissolved solids concentrations from
5.5 mgtl in a small mountain reservoir at Indian Mountain to
)0
213 mg/l as winter (April) flow of the Porcupine River in interior
Alaska. Major streams have dissolved solids concentrations averaging
about 120 mg/l during summer and about 170 mg/l during winter.
A few of the streams have excessive iron content during parts of the
year and some streams contain glacial sediments during the summer.
Sediment: (This discussion is applicable to the Central, Upper
Tanana and Koyukuk portion of the Yukon Region.) Both topography
and drainage patterns govern, to some extent, three types of normal
summer suspended sediment concentrations in thiR subregion.
Normal suspended sediment concentrations as high as 500 mg/l may
characterize water in streams in the Brooks Range. Sources of this
sediment load may be both normal erosion in mountainous areas and
mass wasting through solifluction. The small nonglacial tributaries
probably carry normal sediment concentrations as low as 5 mg/l during
the summer because their drainage is underlain by permafrost and
there is limited opportunity for erosion.
Streams in the southern part of the Yukon basin carry between 10 and
300 mg/l of suspended sediment during the summer. Although glaciers
are absent in the mountains, periodic sediment samples from the Chena
River indicate the normal suspended sediment concentrations may be as
much as 300 mg/l.
SI
The streams in the remainder of the area, except the Yukon River,
are all generally expected to carry 100 mp,/l or less of suspended
sediment during the summer.
The most heavily sediment laden stream of the area is the Yukon River.
Its concentrations varies with surface and dilution. It ~athers most
of its suspended sediment load from large glaciers at its headwaters
in Canada. During the summer, the reach of the Yukon from the
Canadian border to the Porcupine River at Fort Yukon carries a normal
suspended sediment load of about 300 to 400 mg/l. The Porcupine River
water contains less suspended sediment (100 mR/l) and causes a dilution
effect on the Yukon River, also a lessening of stream gradient exists
below Fort Yukon. Thus, the Yukon River between Fort Yukon and Tanana
supports only about 200 to 300 mg/l of suspended sediment. When the
Tanana River enters the Yukon River, the suspended sediment concentration
of the Yukon increases back up to about 300 to 400 mp,/l. At the
Koyukuk-Yukon confluence at Koyukuk, the concentration is again somewhat
diluted. However, being smaller than either the Porcupine or Tanana
Rivers, the Koyukuk's effect is not as great and the Yukon River still
may carry slightly over 300 mp,/l for some distance below Koyukuk.
All of the sample points used are in the lower elevations. At these points,
70 to 80 percent of the normal summer suspended sediment is finer than 0.962 mm.
At higher elevations, the particle size distribution would be expected to show
a smaller percentage of fine material.
....
The few winter samples indicate that most streams carry less than
15 mg/1 of suspended sediment during the winter.
On the basis of a few temperatures taken throughout the year, the
range of normal summer temperatures appears to be between 7 0 C and
100 C (45 0 F to 500 F) and of winter temperatures from 0 0 C to 2 0 0
(32 0 F to 36 0 F).
Existing Problems: The problems of this region are similar to those discussed
under the Lower Yukon Subregion of this report. See that discussion.
Potential for Water Resource Development
At present the area is sparsely populated, has few roads, and the
water resources are virtually undeveloped.
Little exploratory work has been done to delineate the area's ~round
water potential. Large amounts of ground water should be available
in areas having permeable unfrozen gravels. However, extensive work
will be required to discover sites for wells or. infiltration galleries.
The greatest potential by far is for surface water development.
particularly for water power. The undeveloped power sites on the
Yukon River and its tributaries account for approximately 50% of the
potential hydropower of the state.
The potential for development of surface water for recreation is also
great. The lakes and swamps are valuable wildlife habitat and the
streams contain many fish. Many of the streams are navigable.
53
Water Supply: Because of low population very little development or
use of surface water or ground water has taken place in the area.
Water consumption is estimated to be about 200,000 gpd. ~tilitary
installations have the most complete water supply facilities and use
about 80,000 to 100,000 gpd. Few communities have more than one well
and residents of many communities use river water only. Although
numerous lakes exist in the Yukon Flats, little if any use is made
of lake water. Springs, especially the thermal springs, have been
used for many years to irrigate small truck farms and to supply both
houses and pools at resorts. Use of the spring water is slight, however,
compared to total use of water in the area.
The development of a reliable potable water supply ard distribution
system is needed by most villages. Its concomitant of sewage collection
and disposal will become even more important with increasing population.
Several water storage sites have been identified in the area. These
are shown on the 1:250,000 scale maps and Map 5. Also see the report of
Communities. -----------
Flood Control: The List o~_U~_~~~ac~~-F~~j~~~ard, prepared by the
Alaska District Corps of En~ineers indicates that many of the villages
along the Yukon are subject to some degree of flooding. Ice jams and
stream overflow appears to be the major cause of flooding with erosion
of the riverbanks a secondary problem. See Map 5.
t .t. t ~ "
158 0
,
r , -1-,
MopS
~URFA.CE WATER RESOURCE
PoIen'ial Flood,n9 and '110'". 0.".10 .......
o
Opportun,',,,
PD' ... ·;,,' Floodi"9
Pat"",al W", .. St ... ,. Si,.
Poten'ia! Hydroelectric Site
Pcooten,j,,1 c..".,1 Sit.
55
At least three alternatives are available to assist in protection of
life and property.
1) development of "new towns" outside the flood plain.
2) local protection works such as levees and bank stabilization aid.
3) control of the flow of the river(s) via darns and impoundments.
Numbers 2) and 3) are difficult to justify on economic grounds.
Number 3) t,Till be. further discussed under Power.
Navigation: Improvements could include dredging, bank stabilization,
removal of obstacles, navip,ation aids, improved port/dock facilities,
and control of the water level.
Power: Several sites in this region have been identified as having
potential for major hydropower production and flood control. Two,
Melozitna and Ruby are within this subregion.* See Table 3 and Map 5.
Timing of any major development on the Yukon River and decisions on
type and scale depend on future needs including flood control. water
transportation, water supply, power, and other purposes.
*The damsite for the potential Rampart Project is located in this subregion.
However, almost the entire reservoir is located in the Upper Yukon Subregion.
It will be discussed as a part of the Upper Yukon.
..
,..,
\
.'
. .,
The Melozitna dam and 58.500 kilowatt power plant would be on the
Melozitna River 11.5 river miles from its mouth.
The Melozitna River drains a mountainous area of 2,659 square miles
above the proposed damsite. The drainage basin lies north of the
Yukon Basin and south of the Koyukuk drainage area. The Melozitna
River heads in the Ray Mountains and meanders down the valley it has
formed, to the north of the Kokrine Hills.
From various stream flow records the average annual runoff at the
damsite was estimated at 1,400,000 acre feet.
The Melozitna Reservoir, with normal maximum water surface at elevation
550, would have a total capacity of 2,000,000 acre feet. The 1,800,000
acre feet of active storage would provide for 91 percent regulation
of the flows of the Melozitna River for power production. Average
tailwater was assumed at elevation 225, yielding a net average head of
270 feet. With the above values of head and flow and 80 percent
efficiency, the proposed development would be capable of producing
32,200 kilowatts of continuous power. The installed capacity of the
proposed development would be 58,500 kilowatts.
The Melozitna Reservoir would be formed by building a concrete arch
dam across the Melozitna River. The crest of the dam would be at
elevation 555. The base was assumed at elevation 200, for a maximum
57
structural height of 355 feet. The crest would have a len~th of
about 1,200 feet and a heir,ht above the river of 330 feet.
The most favorable of the main stem potentials in Alaska are the
upstream Woodchopper and Rampart Pro1ects, the Ruby Pro;ect, and the
downstream alternative of a Kaltag or Holy Cross Project.
The Ruby site is the most favorable storage potential between the
mouths of the Tanana and Koyukuk Rivers and would be a key unit in any
plan to develop the power, navigation and related potentials of the
Yukon River. It also could be a key to providing flood protection on
the Yukon River below the Tanana River.
The studies of the Ruby Project to date have been largely limited to
considerations of the project as a single purpose hydroelectric
development operating in conjunction with the Ramnart Project. Reservoir
elevation would be at 210 feet, the tailwater level at the Rampart
power plant.
However, the available topographic maps and geologic inspection of the
damsite indicate a Ruby Project could be developed to fullv re~ulate the
Yukon River at the site without upstream storage. Thus, the Ruby
Project is a key storage potential on the Yukon River that could be
developed either independently or in con1unction with any of several
possible upstream storage systems. It represents the first opportunity
to regulate Yukon River flows downstream from the Rampart site and the
Tanana River (See Upper Yukon discussion). This is of additional
,.,,*,
importance as the opportunities for regulation of Tanana River flows
on the Tanana River are not promising, and the Tanana River with a
drainage area of about 44,000 square miles is a major flood contributor
to the Yukon River.
Between reasonably maximum (water surface elevation 325 feet) and minimum
sized Ruby (210 feet) reservoirs are several alternatives depending
upon the degree to which upstream regulation of Yukon River flows may
be developed. For example, rough hydrology studies indicate that, with
an upstream Woodchopper reservoir (See Upper Yukon discussion) a Ruby
reservoir to elevation 280 could provide reasonable regulation of Yukon
River flows at the Ruby site.
Should the development of other major upstream storage potentials be
precluded or limited, the Ruby reservoir would be essential to regulation
of middle Yukon River flows.
The 256,200 square mile drainage basin tributary to the Ruby damsite,
and average annual runoff of 109 million acre feet at the site, emphasize
the importance of the Ruby Project in planning for regulation and
development of Yukon River flows.
The following tabulation presents additional data for the low Ruby
Project, and for one with reservoir to elevation 325 (without upstream
storage). Both potentials include a concrete gravity dam about three
miles upstream from the town of Ruby
Because of its strategic location for regulation of basin flows and
its large energy potential, the Ruby Project is considered to have
statewide and national significance. The energy value of the site
S'I
indicates the magnitude of the resource --this would be about
$45 to $65 million per year for the low project and $100 to $140 million
per year for the high project, assuming average energy cost of
from seven to ten mills per kilowatt hour.
The value of the site for navigation, flood control, power and
other purposes, and the absence of suitable alternatives, establishes
that a major dam at the Ruby site would be a key unit in any long-
range plans for the basin.
Reservoir
-----------------------------------_._-----------_._-----------------------
Plan
Low!/
High-?I
Elevation
(Feet)
210
325
Length
(Miles)
115
Area
(Sq. Mi.)
2,650
3,360
Storage
(Ac. Ft.)
17,000,000
Dam
Height
(Feet)
83
198
The low Ruby Project would have an annual average energy production
of 6.4 billion kilowatt hours, with installed capacity of 1.46
million kilowatts at 50 percent load factor. The comparable figures
for the high project would be 14.2 billion kilowatt hours and 3.25 million
kilowatts.
The project would result in lower flood stages and increase winter
flows below the damsite. A reduction in ice jam problems would be
anticipated as a result of stabilized flows.
II With Rampart Project
11 Without upstream storage
/'0
The town of Tanana would require relocation. For the high
plan, the additional villages of Rampart and Stevens Village
would require relocation.
Recreation: See Lower Yukon discussion.
~: See Lower Yukon discussion.
Wildlife: See Lower Yukon discussion.
"
V Koyukuk
F~isting Situation
General: The Koyukuk Suhrer,ion of the Yukon Region includes all or
a portion of the following physiographic sections: Central and Eastern
Brooks Range, Amhler-Chandlp.r Ridge and Lowlands, Kanuti Flats,
Kokrine-Hodzana Highlands, Indian River U~land, Koyukuk Flats, Nulato
Hills, Pah River Section.
The Schwatka and Endicott Mountains of the Brooks Range--hounding the
region on the north--are the major sources of water runoff sllpplyin\!
the river systems of the Koyukuk and Kanuti. To~ether wi th trihutary
supplies from east and west, these waters swell the Yukon's volume at
the junction of the Kovukuk and Yukon.
The climate in the region is incompletely known due to the lack of data,
particularly above 1,000 feet in altitude. But. as might be expected,
the temperatures are characteristicallv continental. A range between
extremes exists at Allakaket of 168 degrees. Mean maximum temperatures
in the months of June and July are in the 60's; and in the months of
December, January, and Februarv from ten below to five above. }1ininum
averages in comparable months are in thp. 40's in summer and ten to
30 below in winter. As characteristic of northern latitudes, the
coldest minimum temperatures are at lm"er altitudes.
l'lI!!Jt
158 0 156 0
--!-----4-
I
I
I
---r------------
I
8BO ____ c~
L ___ -J-~--+-------:--660
Map6
KOljuku k
63
Annual precipitation amounts appear to range from about ten to
17 inches with isolated amounts to 20 inches in the area.
Prevailing air flow in this part of the region is from a northerly
direction--down the south slope of the Brooks Range. Since "down
slope" winds are characteristically dry, the light precipitation
is explained. Unusually strong winds are rare.
Glaciers are absent but the region is underlain by permafrost,
except beneath large lakes, rivers and recently formed flood plains.
Much of these lowlands are covered by water laid and windborne silts.
Alluvium deposits are often quite deep.
Streams: See Lower Yukon discussion.
!''It'
Distribution of Runoff: See Central Yukon discussion.
Lakes: See discussion of the Lower Yukon.
Storage: See discussion of the Lower Yukon.
Chemical ~~ality: See discussion of the Central Yukon.
Sediment: See the discussion of the Central Yukon.
Existing Problems: The problems of this region are similar to
those discussed under the Lower Yukon Subregion of this report.
See that discussion and Map 7.
880 _~ ---t-------L-
660~.
•
r :'" USIiS •• P ( DHf'!
..
Mop7
SURFAcE WATER RE~RCE
p", ... hal Fl<>o>d'ng and Wal •• o. .. lopMft'
Opportu",I,U
Pol ... • .. >I Flood'''11
PoI""I'ol WO'" il C"'''-Site
Pot"",01 Hy ... lKtri. ~te
P", .. nl;ol Cnnal iiI.
Potential for Water Resource Development
The discussion of potential development for Water Supply, Flood Control.
Navigation, Improvements, Recreation, Fish and Wildlife, is i.ncluded in
the Central Yukon Subrep,ion.
Power: Several sites in this ref-ion have been identified as havinp,
potential for major hydropower production and flood control. Three,
Dulbi, Hur,hes, and Kanuti are located in this subregion. Timing of
any major development on the Koyukuk River and decisions on type and
scale depend on future needs includinp, flood control, water transportation.
water supply, power, other purposes and evaluation of environmental impacts.
The potential Dulbi Dam and power plant would be on the Koyukuk River
at latitude 65°26'N and longitude l56°22'W, about 150 miles above the
river mouth. The reservoir lies in an area known as the Koyukuk Flats.
The alluvial terraces, forming the abutments, consist entirely of
unconsolidated silts, sands and gravels, and would not provide an
adequate foundation for a concrete dam.
The Koyukuk River drains an area of 25,660 square miles above the damsite.
The Koyukuk drainage basin is a mountainous area north of the Yukon
River and south of the Brooks Range. The river meanders throur,h a wide
flat valley for much of its length. Sand dunes cover a portion of the
valley floor. Permafrost zones are present in the basin.
Using stream flow records, the average annual runoff at Hughes was
estimated at 12,400.000 acre feet.
.w
..
".'
, ....
,""
,"",
A determination of the unit runoff for the area above the Dulbi damsite
and below the Hughes gage was made using the runoff records at Hughes,
Ruby, and Kaltag. The average annual runoff from this area is estimated
at 6,800,000 acre feet. The total average annual flow at the Dulbi damsite,
based upon the above determinations, is estimated at 19,200,000 acre feet.
With the maximum normal water surface at elevation 225, the Dulbi
Reservoir would be adequate to fully regulate the flows of the Koyukuk
River for power production.
Average tailwater was assumed at elevation 147, yielding a net average
head of 68 feet.
The current plan for the Dulbt site would generate an estimated 122,000
kilowatts of continuous power at 80 percent efficiency. The proposed
installed capacity of this development would be 222,000 kilowatts.
Three proposed plans were studied to determine the optimum scheme.
The alternative plans had normal maximum water surfaces at elevations
225, 250, and 275. It was determined that development to elevation
225 was the optimum for this site.
The Dulbi Reservoir would be formed by the construction of an earth
dam across the Koyukuk River. The main darn would have the crest at
elevation 245 with the assumed low point of the dam at elevation 130,
for a maximum height of 115 feet. The crest of the dam would be 98
feet above the river and 7,300 feet lonr,. Several low earth dikes would
be required to close low points in the rim of the reservoir several
miles to the northwest of the main damsite. It is impossible to
determine the exact number, heights or lengths of the dikes from the
available data.
The power plant would be built at the toe of the dam. Four
generators of 55,500 kilowatts would be installed in the power
plant, making a total installed capacity of 222,000 kilowatts.
Average tailwater was estimated at elevation 147.
About 200 people would have to be relocated from the reservoir
area, mostly from the village of Kuslia, population 168 (1960 census).
The potential Hughes Dam and 100,000 kilowatt power plant would be
on the Koyukuk River at the village of Hughes. The site is
380 river miles from the mouth at latitude 66°03'N, longitude
l54°l6'W.
The Koyukuk River drains an area of 18,700 square miles above the
Hughes damsite.
The Koyukuk drains a mountainous basin lying between the Yukon
River on the south and the Brooks Range to the north. The river
meanders through a wide, flat valley for much of its length. Perma-
frost conditions prevail throughout the area.
Stream flow records were extended back to 1957. The recorded and
correlated flows at Hughes show an average annual runoff of 12,400,000
acre feet. The Hughes Reservoir would contain 1,150,000 acre feet of
storage, with the normal maximum water surface at elevation 320. The
flows of the river would be regulated by the Kanuti Reservoir,
a proposed upstream development assumed to be constructed prior
to the Hughes Project.
Average tailwater was assumed to be at elevation 270, yielding
a net average head of 49 feet. The Hughes development would be
capable of producing 55,000 kilowatts of continuous power. The
installed capacit.y of the project would be 100,000 kilowatts.
The power plant would be built at the toe of the dam. Four
generators of 25,000 kilowatts each would be installed for a
total capacity of 100,000 kilowatts.
The village of Hughes would have to he relocated. Hughes had a
population of 85 according to the 1970 census.
The potential Kanuti Dam and power plant would be on the Koyukuk River,
36 river miles above the village of Hughes. The site is about one half
mile upstream from Honeymoon Creek, at latitude 66°2l'N and longitude
l53°38'W.
A visual ~eologic reconnaissance was made in June 1965.
were examined in connection with this project.
Two sites
The Kovukuk River drains a mountainous area of 17,970 square miles
above the Kanuti damsite. The basin lies north of the Yukon River and
south of the Brooks Ranp;e. The river meanders back and forth through
a wide flat valley for much of its length. Permafrost is prevalent
throu~hout the basin. Fromstream flow records, the averar,e annual
runoff was estimated at 11,900,000 acre feet.
Based upon observations of the Koyukuk River in ,Tune 1965 and results
of sediment studies made on other Alaska streams, the annual sediment
accumulation in the proposed reservoir was estimated at 0.2 acre feet
per year, a negligible amount.
The proposed Kanuti Reservoir would fullv re~ulate the flows of the
Koyukuk River for power production, not only at the Kanuti site but
at the downstream Hughes site as well.
Average tailwater was estimated at elevation 320, normal maximum water
surface elevation at the Hughes site. The net average head obtained
from the proposed Kanuti development would be 166 feet. At 80 percent
efficiency, the above water supply and average head would produce 184,000
kilowatts of continuous power. The proposed installed capacity would
be 334,000 kilowatts.
The reservoir would be formed by the construction of a concrete gravity
dam across the Koyukuk River with the crest at elevation 505. The base
was assumed at elevation 270 for a maximum structural height of 235 feet.
The dam would have a height above the river of 185 feet. The crest
length of the dam would be 5,850 feet.
The power plant would be built at the toe of the dam. Four generators
of 83,500 kilowatts each would be installed for a total capacity of
334,000 kilowatts. Average tai.1water would be at elevation 320.
Approximately 110 people would be relocated from the reservoir area,
mostly from the village of Allakaket.
71
VI Upper Yukon
Exisin~ Situation
General: The physiographic sections and parts within the Upper Yukon
Subregion include: Yukon Flats. Porcupine Plateau, Ogilvie Mountains,
Tintina Valley. Yukon-Tanana Upland draining to the Yukon, the Rampart
Trough, Kokrine-Hodzana Highlands draining to the Yukon. eastern part
of Arnber-Chandalar Ridge and Lowland. and south slope of eastern Brooks
Range.
Although this re~ion is rimmed by mountainous terrain from its apex
at the junction of the Yukon and Tanana Rivers westward and north and
westward to the Canadian border, the dominant physiographic feature of
the region is the marshy. lake dotted Yukon Flats. See Map 8.
This Flats section rises to altitudes of 100 feet in the west and 600
to 900 feet in the north and east. Gentle, sloping, outwash fans of
the Chandalar. Christian and Sheenjek Rivers make up their northern
part. The southeastern part of the flats is the broad gentle outwash
fan formed by the Yukon River, while other areas are nearly flat flood
plains. Boundaries with surrounding uplands and mountains are gradational.
Two rivers--the Yukon and a major tributary, the Porcupine--extend dominant
influence over the area. The Yukon has a braided section course
southeast of tile bend at Fort Yukon and a meandering course with many sloughs
southwest of Fort Yukon. Tributaries risinr, in the surrounding uplands
68
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Upper Yukon ~ubre{l'0n
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tend to have meandering reaches through the flats. Thaw lakes are
abundant in the flats and common, along with thaw sinks, in the
marginal terraces.
Permafrost underlies most of the flats except for the rivers; glaciers
are absent.
Geologic evidence points to the Yukon Flats aR the site of a late
Tertiary lake.
The Yukon River enters the Rampart Trough through a narrow, rocky gorge
and meanders gently through a narrow flood plain. The Rampart Trough
is incised 500 to 2,500 feet below highlands on either side, havin~
been eroded along a tightly folded belt of soft coal bearing rocks of
Tertiary age.
To the north of the trough the basin is initially formed by the Kokrine
Hodzana Highlands--even topped, rounded rido;es risinp; from 2,000 to 4,000
feet in altitude and occasionally surmounted by more rugged mountain
groups.
North of these highlands and the flats, the Porcupine Plateau slopes
upward towards the Brooks Ran~e, the northern extension of the Rocky
Hountain system. The Brooks Range within this rep.ion is a wilderness of
ru~ged, glaciated, east-trending ridges risin~ from 4,000 to 6,000 feet
in altitude with few lakes.
, ..
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...
The Chandalar, Sheenjek and Coleen Rivers rise in the Brooks Range,
then flow south across the Porcupine Plateau to the Porcupine and Yukon.
The eastern boundary of the region is the Canadian border, near which
rise the Ogilvie Mountains thrusting sharply and precipitously upward
to 5,000 feet in altitude. Drainage from these mountains to the Yukon
is by way of Kandik, Nation and Tatonduk Rivers.
The Yukon-Tanana Uplands form a southeastern and southern boundary to
the region. These uplands, characterized by rounded, even-topped
ridges with gentle slopes, are the Alaska equivalent of the Klondike
Plateau in the Yukon Territory. Surmounted in places by compact, rugged
mountain groups 4,000 to 5,000 feet in altitude (the White and Crazy
Mountains), they drain south to the Tanana River and north to the Yukon
through irregular divides.
The TPgion experiences a typical Arctic continental climate, severe
winters and warm summers. After freeze-u~ of the rivers and marshes,
the region is a source for very cold, continental Arctic air. Extended
periods of fifty to sixty degrees below zero temperature are common
and 75 below has been recorded. Summers are warm with temperatures
reaching the 80's each year and occasionally the 90's. Despite high
summer temperatures, however, diurnal variations can be extreme;
freezing temperatures have been experienced in each month of the year.
The continental climate provides mo~t of the preci~itation within
the region in the normal form of convection showers.
1S
':1{\<
The avera~e snowfall each winter is about 45 inches. Due to extremely
cold temperatures, accumulations on the rround approach this averao,e
as well.
Streams: See the Lower Yukon discussion.
Distribution of Runoff: See the Central Yukon discussion.
Lakes: See the Lower Yukon discussion.
Chemical ~~~~: See the Central Yukon discussion •
. Storage: See the Lower Yukon discussion.
Sedimentation: See the Central Yukon discussion.
Existing Problems: The problems of this region are similar to those
discussed under the Lower Yukon Subregion of this report. See that
discussion and Map 9.
Potential for Water Resource Development
The discussion of potential development for Water Supply, Flood Control,
Navigation Improvements, Recreation, Fish and Wildlife is included in
the Central Yukon Subregion. See Map 9.
Power: Several sites in this re~ion have been identified as having
potential for major hydropower production and flood control.
Rampart, Porcupine, and Woodchopper are located in this subregion. See Map 9.
The potential Rampart Dam and power plant would be on the Yukon River
750 river miles upstream from the mouth. The dam would be 31 river miles
downstream from the village of Rampart at latitude 65°20'N, longitude ,.
151001'W.
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Map9
SURFACE WATER RE!.OURCE
Pohntial Flood,ng and Wat .. o.r..l0~
Opportu,,.,i ••
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Potential Flooding
Potential Wot" ~ ..... Site
Pot.."iol Hyd, .. I.ctric Sit.
P"'.ntio\ Canol Sit.
7/
The Yukon River drainage area above the damsite is 200,000 square miles.
Permafrost conditions exist throughout much of the Yukon River Basin.
Continuous records of the flows of the Yukon River at the village of
Rampart are available from June, 1955 to the present. Based upon the
first eight years of records obtained at this site, the Corps of
En~ineers estimated an averap,e annual flow at the damsite of 81,000,000
acre feet.
The Rampart Reservoir at normal maximum water surface elevation 665
would contain a total storage of 1,265,000,000 acre feet. To fully
regulate the flows of the Yukon, only 142,000,000 acre feet of this
storage would be,required. Average tailwater was assumed at elevation
210. The net average head was found to be 445 feet. The dam as
outlined above, assuming an efficiency of 90.6 percent, would produce
3,904,000 kilowatts of continuous power. The installed capacity would
be 5.040,000 kilowatts.
The reservoir would be formed by the construction of a concrete gravity
dam across the Yukon River. The dam would have a maximum structural
height of 570 feet from the base at elevation 110 to the crest at
elevation 680. The crest of the dam would be 470 feet above the river
and 3.100 feet in lenp.th.
The power plant would be at the toe of the dam. Sixteen generators of
315,000 kilowatts each would be installed for a total capacity of
5,000,000 kilowatts.
18
'.
. ..
The towns of Beaver, Stevens, Fort Yukon. and Venetie would have to
be relocated from the reservoir area. There are no hip.hways that might
require relocation. Construction cost per installed kilowatt = $238.
This project would have the largest installed capacity of any project
on the North American continent, and would provide the most economical
power of any project in Alaska.
The site has been reported on by the Corps of Engineers in their
Interim Report No.7, dated February 1964. Their plan proposes the
following:
"Through the eastern portion of Alaska, the Yukon flows across
the relatively lDlv ridges of the Central Plateau province. The
river has cut through the bordering ridges. forminp, a Hell defined
channel and in many places, a canyon section. In one of these canyon
sections, near Rampart, there are several potential sites for a
dam, which, if developed, offer a hydroelectric potential
unprecedented on the North American continent at this time.
Rampart Canyon, within a confined reach of about 30 miles, is
located approximately at river mile 750. The site area under
study is immediately downstream from the mouth of Texas Creek and
approximately 36 miles northwest of Eureka (which is connected
to Fairbanks by road), about 100 air miles northwest of Fairbanks.
and about 290 air miles from Anchorare in the Cook Inlet area.
The tributary draina~e area of the site is about 200.000 square
miles. • • The period of low flows of Yukon River occur during
the colder months of November through April when the river is
covered with ice. The remaining months see the higher flows, with
the peak flood flows occurring between the latter part of May
and the first part of June • • •
Present power studies are based upon storage of 7S percent of the
mean annual flow during the filling period. The passage of 25
percent of the flow is considered adequate, pending further detailed
study, to permit the passap,e of anadromous fish and to provide
adequate water for downstream navigation. With a pool of elevation
660, the prime power available would be 3,735,000 kilowatts •••
Permissable overload operation of this basic plant would provide a
peakin~ capability of approximately 5,500,000 .
------------------------------------~
A pool to elevation 660 would raise the present low water surface
about 445 feet at site. The volume of the pool at this elevation
would be about 1,252,000,000 acre feet and would create ~ reservoir
surface area of about 6,950,000 acres or 10,850 square m1les. This
man-made lake would be over 400 miles long and, in the reach of .
Yukon Flats area, over 80 miles wide. The entire reservoir area 1S
inhabited bv an estimated 1,500 people. Fort Yukon, a town of about
600 people,-is the largest community in the area. Several smaller
Native villages and the Venetie Indian Reservation would be
partially inundated by the reservoir.
Based upon engineer1ng coris1deratio'ns only, the approximate magnitude
of project costs have been investigated. Utilizing January 1962
price levels, the eRtimated toatl project costs would be about
$1,300,000,000 for the presently propoRed power installation of
4,760,000 kilowatts. The annual generation from this installation
would be about 33,000,000,000 kilowatt hours."
The Department of the Interior has studied the effect of the project on
the natural resources of the state and has analyzed the posBi.hle markets
for the power. These studies are available in the three volume Dept. of
Interior Field Report, "Rampart Project, Alaska: HARKET FOR POWER AND
Woodchopper would store and regulate flows from the upper one third of
the basin. It is the only feasible main stem stora~e site in Alaska
above Rampart Canyon. It has potential storage capacity of 92,000,000
acre feet, with rool elevation at 1.100 feet, and could provide essentiallv
full re~ulation of the site.
The statewide water power inventory indicates Woodchopper is one
of the five most important hydroelectric potentials of Alaska
on the basis of size and cost. In addition to Woodchopper, this
group of projects includes Rampart and Yukon-Taiya in the Yukon
basin, Wood Canyon in the Copper basin, and the Upper 8usitna
Project.
Should the development of the Rampart site be limited, other
major storage potentials, particularly the Woodchopper reservoir,
would be increasingly vital.
The studies of the Woodchopper Project have been largely limited to
considerations of the project as a single purpose hydroelectric
development operating in conjunction with the Rampart Project.
Evaluation of the project as a separate, multiple purpose develop-
ment would greatly emphasize the importance of the site in long-range
plans for the Yukon River basin.
----~----~-----~-------
The attached summary tabulation from the statewide water power inventory
gives comparative data on the projects mentioned above. See Table 3.
The most recent project studies are premised on a concrete gravity
dam about one half mile below Woodchopper Creek raising the water surface
to elevation 1,020 at or about 3f)O feet above the present river elevation.
This \JIllild creal£' tt storage l~aJlill'flY of ;'iI,Ollil,fHlO nC'n; fed all4l .Jt'!vt'!lnp
mORt of the hydrn pOlrontlnl of fliP f'litf'.
consideration~. with a maior portion of the trihutary ba!;in and part of
the reservoir in Canada.
~I
Estimated firm power potential for this plan is 2,160,000 kilOl'latts
at 75 percent annual load factor with annual firm energy production of
14.2 billion kilowatt hours. For comparison, Rampart Project has an
energy potential of about 31.7 billion kilowatt hours per yenr.
The reservoir under this project plan would have a surface area of
about 563 square miles, a shoreline of about 800 miles and an active
capacity of 39,000,000 acre feet. The Alaska portion of the reservoir
totals about 470 square miles, is about 115 miles long, and inc.ludes
the town and village of Eagle.
Alaska, Market for Power and Effect of Project on Natural Resources"
included the following points:l) It is probable that a substantial
portion of the anadromous fish runs that pass the Rampart site also
pass the Woodchopper site. Construction of the project would create
a barrier to these runs and would require the construction of fish
passage facilities. 2) The reservoir area also includes excellent
wintering habitat for a high density moose population.
3) Significant portions of the Steese-Fortymile herd of caribou
cross the Yukon in the reservoir area during thei r migrations to ;mel
from Canada. 4) The pro1ect WOllld havp moderate to fnAi,J,n1firllnl
impllct4 to wtlt(·rrllwl. rurhl'nrlrll' nn(1 rnml' 11IIImllll1 ollll'r 111:111 IIIIHH'
mentioned. 5) Owing to its relatively small size. construction of
the Woodchopper Project would have a lesser fish and wildlife
impact than the downstream reservoir sites.
The project studies establish the engineering feasibility and the
favorable potential power values estimated at $100 to $150 million
per year on the basis of average energy costs of seven to ten mills
per kilowatt hour. The studies are of rough reconnaisflance grade.
More detailed, multiple purpose studies may show considerable chan~es
in the project plan would be desirable to provide optimum basin
benefits.
Any decision to develop and operate. the Woodchopper Project would
require joint U. S. and Canadian consideration of the resources and
long range needs and alternatives of the Yukon Basin as a whole.
Woodchopper Pro.1 ect is an identified maior water resource development
potential. There are no active proposals to construct it, and studies to date
relate primarily to establishing the resource values involved.
Because of its stratep,ic location for regulation of basin flows and
its large energy potential, the Woodchopper Project is considered to
have statewide, national, and international significance. The energy
value of the site indicates the magnitude of the resource--this would
be $100 to $150 million per year assumin~ average energy cost of
from seven to ten mills per kilowatt hours afl stated ahove.
absence of suitable alternatives establishes that a maior dam at the
Woodchopper site would be a key unit in any lonp, range plans for the
basin.
,.",
The Porcupine River has a drainape area of 46,200 s~uare miles, or
nearly 15 percent of the total Yukon basin. Roughly one half of the
basin is in Canada. Based on available: stream flow data, the
Porcupine contrihutes around eir,ht to ten percent of the total Yukon
runoff.
Several potent:l.al damsites which appear to have favorable topography
and geology exist in the canyon reach within about 50 miles downstream
from the Canadian border. A very substantial storap:e potential exists,
with most of the reservoir area in Canada.
Studies preparpd for th£> statewide hydro power inventcry, which arp
ciescrihed suhsequently, establish that a Porcllpine Pro1cC't would h.1Vp
reasonahly attractive unit costs as <t sfnrlp lllJrpose hydro pro1pct.
However, the site is potentially more important for its strategic
location with respect to any plans for storap,e and rer,ulation of flows
in the upper Yukon basin.
A storage development on the Porcupine, top,ether with a Woodcho~per
Project, would substantially re~mlate Yukon basin flows above Rampart
Canyon.
The proiect would provide storap,e for regulation of Yukon River flo\-7s
for power and other purposes. Porcupine damsite is on the Porcupine
River above the Yukon Flats, and about 12 river miles below the Canadian
border. Drainape area above the damsite is about 23,400 square miles.
Inventory r;rade plans assumed a concrete arch dam with a maximum hei~ht
above foundation of about 400 feet and a crest lenr,th of about 1,600
feet. Water supply is estimated at 9.1 million acre feet per year,
averap,e.
The reservoir would affect only seven square miles in the U. S. and
have a shoreline of 46 miles. A much larger portion of the reservoir
would be in Canada.
The project has an estimated firm enerr,y potential of 2.32 billion
kilowatt hours per year, equivalent to 265,000 kilowatts of continuous
power, or 530,000 kilowatts with a 50 percent load factor. Annual
value of the power would be around $15 to $20 million assuming a
power cost of from seven to ten mills per kilowatt hour.
Environmental aspects have not been examined in any detail.
There are no active studies or proposals to develop the project.
Because of its strategic location with respect to storage of Upper
Yukon Basin flows and indicated favorable unit power costs, the project
is considered significant in any long range plans for the Yukon Basin.
At this time, the Porcupine and Woodchopper Projects appear to be the
most feasible opportunities to develop upstream storage in the Alaska
portion of the Yukon Basin.
Any decision to develop or not develop the Porcupine site would
logically be made on the basis of joint U. S. and Canadian consider-
ation of the resources involved and long-range needs and alterna-
tives for conservation and development within the Yukon River
Basin as a whole.
The project would result in lower flood stages and increase winter
flows below the damsite. A reduction in ice jam problems would
be anticipated as a result of stabilized flows.
..
VII Tanana
Existinp. Situation
General: The region consists of the fo11m.;ring physiographic sections
and parts: The Yukon-Tanana Upland draining to the Tanana, the Northway-
Tanacross Lowland, eastern Alaska Range draining to the Tanana, the
Northern Foothills, Tanana-Kuskokwim Lowlands draining to the Tanana,
the Tozitna-Me10zitna Lowland draininp, to the Tanana, and the Nowitna
Lowland draining to the Tanana.
Dominating this re~ion, particularly insofar as human occupancy is
concerned, is the Tanana River, a major tributary of the Yukon.
Below and north of its source in the r,la".iers ard slopes of the Wrangell,
Mentasta clOd Nutz(ltin Mountains, t~le Tanana drains the Northway-Tanacross
Lowland. Here deposits of glacial outwash have pushed the Tanana against
the north side of the lowland. This lowland may have been captured in
Pleistocene times from the Yukon for the drainage divide of that river
is only tl.;rO to five miles north and east of the Tanana, nearly straddling
the United States-Canada border. See Map 10.
There are no glaciers in the lowland, but discontinuous permafrost is
present. Thaw lakes abound in areas of fine alluvium and several large
lakes abuttinr, the surrounding upland also exist possibly caused by the
a11uviation of the lowland.
~7
150·
\
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142 '
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, ,
As the Tanana flows towards a confluence with the Yukon, the valley is
compressed between the Clearwater Hountains and the Northern Foothills
of the Alaska Range before it enters the broad depression of the
Tanana-Kuskokwim Lowland, bordering the Alaska Range on the north.
Here coalescing outwash fans from the Alaska Range slope twenty to fifty
feet per mile to the flood plains of the lowland. Here, too, the central
"trough" of Alaska, through the Intermontane Plateau physiographic
division of the state ends with abutments upon the Yukon-Tanana Upland
and its White and Crazy Hountains.
The massive Alaska Range to the south and west of the region effectively
shelters the Tanana Valley from nearly all maritime influences.
Consequently, the area has a definite continental climate, conditioned
in large measure by the ready response of the land mass to solar heat
variations throughout the year.
In the sunnner months of June to July, the sun is above the horizon 18
to 21 hours each day, and during this period, average maximum daily
temperatures reach the lower 70's, with extremes to 90 degrees or more.
Conversely, from November to ~~rch, when sunshine ranges from ten to
less than four hours per day, lower temperatures are normally regularly
below zero with extremes at or near sixty degrees below zero.
The upland surrounding the valley also tends to aid the settling of
cold air in the lowland.
Ice fog and smoke conditions frequently occur with extremely low
temperatures and air inversion situations.
Precipitation in the region is light, averaging about twelve inches
per year. Growing season moisture begins with light showers in Hay
and builds up to a maximum in August. This is followed by a noticeable
decline to December. Snowfall reaches a maximum in January with the
total fall of February and }larch about half of that realized in January.
The growing season averages about 100 days between a last killing freeze
about May 21st and a first fall freeze about August 30th. The Tanana
Valley has the best chance of any Alaska area for the maturation of
grain crops.
Ice on the river sloughs will generally support a man's weight by
late October and breakup I usually occurs about the first week in ~ay.
Streams: Tanana River at its mouth, drains 44,000 square miles, of
which 500 square miles lie in Canada. The river is formed by the
joining of Chisana and Nabesna Rivers near the village of Northway
and flows generally northwestward 531 miles to its mouth, where it
enters Yukon River at the town of Tanana. From its beginning to Big Delta,
a distance of about 230 miles, Tanana River flows in a valley \-Those
average width is between ten and 15 miles, but below Big Delta the
valley widens to 50 or 60 miles. The Ala£;ka Range flanks the valley on
the left, or southwest, while mountains of considerably less elevation,
separating the Tanana from the Yukon, border the valley on the right.
The major tributaries entering Tanana River are of fairly uniform
drainage area and hav,e their origin in the Alaska Range. Table 4
lists drainage areas and gradients of the principal tributaries in
downstream order.
The gradients of the streams within the basin are steep within the
mountainous regions and gradually flatten as the streams emerge into
the Tanana Valley.
Drainage areas of streams entering Tanana River from the right were
separated from those entering from the left in order to show the
relative proportion of right and left side drainage. Left bank
drainage has its origin in the northern slopes of the Alaska Range,
and its high elevation, numerous glaciers, and relatively heavy
precipitation result in different runoff characteristics from those
experienced in the less rugged areas contributing to the right side
tributaries. Also, the amount of glacier area in each tributary basin
is shown with the area elevation data. The following tabulation
summarizes area elevation data for the Tanana River at its mouth.
Elevation Right Side Left Side Total
in feet Sq. mile Percent Sq. mile Percent Sq. mile Percent
Below 1000 3,800 26.0 8,710 29.6 12,510 28.4
1000-2000 5,410 37.1 6,040 20.6 11,450 26.0
2000-3000 3,550 24.3 4,500 15.3 8,050 18.3
3000-5000-1,780 12.2 6,170 21.0 7,950 18.0
Above 5000 60 0.4 3,980 13 .5 4,040 9.2
Total 14,600 100.0 29,400 100.0 44,000 100.0
Glacier area 0 0.0 1,500 ? I 5.1 1,500 3.4
Hain Stream
Tanana River
"
"
Headwater Tributaries
Chisana River
"
Nabesna River
"
"
Tributaries from Left
Limit
Tetlin River
"
"
Tok River
"
l{obertson River
Johnson River
Delta River
Delta Creek
Little Delta River
Wood River
"
Nenana River
"
"
Kantishna River
"
Tributaries from Right
Limit
Healy River
"
Goodpaster River
"
Salcha River
"
"
Chena River
II
"
"
Tolovana River
"
"
.I.i:iU.Lt! '+
Drainage Areas and Gradients of Principal Streams
Tanana
river mile
entrance
point
530.6
530.6
500.2
466.7
408.4
369.1
299.4
280.7
265.6
168.7
152.1
92.8
341.6
307.8
241. 8
200.4
99.8
Drainage
area
above mouth
sq. mile
44,000
3,270
2,130
940
960
530
380
1,660
720
690
1,390
3,920
6,770
390
1,430
2,170
2,070
3,360
Profile Data
River Reach
from to
river mile
o
200
420
o
63
o
27
61
o
47
70
o
42
o
o
o
o
o
o
45
o
13
122
o
86
river mile
200
420
530
63
117
27
61
75
47
70
80
42
87
32
25
82
38
36
45
114
13
122
143
86
163
19
42
18
71
66
131
135
52
91
125
Average
Slope
ft. per mL
1.1
4.9
3.8
1.3
3.1
3.0
11.8
75.7
1.0
47.3
120.0
5.0
44.2
135.0
42.8
25.7
46.0
30.8
5.3
39.0
12.8
15.8
45.8
1.5
3.9
141
133
151
173
5.0
162.0
3.1
15.1
8.9
22.2
250.0
1.8
8.0
23.3
125.0
0.9
11.1
45.5
o
19
o
18
o
66
131
o
52
91
125
o
133
151
_____ ---,--___________ ----~91.======~--~---------',.,
Source: Harbors and Rivers in Alaska. Survey Report -Interim Report No.4.
Tanana River Basin. Cor s of En ineers Naval Pacific Division
Chisana and Nabesna Rivers head in extensive ice fields and glaciers
on the northern slopes of the Wrangell Mountains. The headwater areas
of these streams are extremely rugged and barren mountains. Mount
Blackburn, the highest peak in the watershed, reaches an elevation of
16,140 feet, and several smaller peaks range in height from 8,000 to
10,000 feet. As these streams emerge from the mountainous regions,
they enter a muskeg area through which they flow to their junction.
Drainage from the muskeg area is extremely poor and is characterized
by an almost continuous succession of lakes and swamps. About half
of the drainage area of Chisana River above its mouth consists of this
flat swampland.
Tributaries to Tanana River entering from the left limit are similar
in character to Chisana and Nabesna Rivers, in that they head in the
high, rugged mountains of the Alaska Range and flow out through the
broad valley floor to their confluence with Tanana River. Nearly all
of these streams are of glacial origin and possess the characteristics
of glacial streams. They are generally swift and steep and carry large
amounts of suspended sediments. The water is milky from glacier "flour"
and the channels in the lower reaches are braided through extensive
gravel deposits in the bottoms of the canyons.
The four principal tributaries from the right are Goodpaster, Salcha,
Chena, and Tolovana Rivers, all of which have similar drainage basin
characteristics. The rolling mountains that form their boundaries are
93
almost entirely below 5,000 feet in elevation. Precipitation is light,
and no glaciers exist in the area. Thick moss overlies a thick turf
known as tundra, which consists of a wet spongy mass of moss roots and
accumulated vegetable matter. The lower areas contain stands of spruce
and birch trees, while the higher ridges bear a growth of thick, tough
brush. Permafrost underlies nearly the entire area, and the active zone
at the surface thaws only from two to three feet each summer. The streams
are clear except during high flows, when light to moderate amounts of
suspended sediment are carried.
Distribution of Runoff: There is little variation in the annual stream
flow patterns. High flows occur in the summer during the months of May
through September, while low flows prevail from November through April.
During the winter, the streams are frozen over with ice from three to
six feet thick, and the principal contribution to flow is gound water
storage. As the ground water storage is gradually depleted, the flow
diminishes to a minimum in March or April. With the advent of above
freezing temperatures in April or May, the flow increases as the result
of snowmelt runoff and causes the spring breakup of ice in the channels.
F0llowing the breakup, flows increase rapidly, and peak flows in the
lower elevation basins generally occur in Mayor June.
The tributaries in the Alaska Range or Wrangell Mountains respond more
slowly to the early summer heat, and their peak flows are generally in
July or August as the result of the optimum combination of maximum
temperatures and areal extent of snow cover contributing to flow. Minor
fluctuations in flow occur with day to day temperature variation as well
as with the diurnal variations in temperature. The period of maximum
precipitation occurs in July or August and these rains,
occurring at a time when temperatures are well above freezing, produce
additional runoff which may add to the snowmelt runoff. On some streams
after the snowmelt runoff has subsided. the rains may produce a secondary
rise which even exceeds the peak of the snowmelt runoff. By October,
subfreezing temperatures cause surface runoff to diminish rapidly, and
base flows characteristic of the winter season prevail.
The runoff patterns for Chisana River, Nabesna River, and Tanana River
near Tok Junction are typical of streams heading in the Alaska Range
and Wrangell Mountains. The high elevation of these basins and large
glacier areas retard the runoff, so that maximum flows occur in July
or August. Chena and Salcha Rivers, whose average basin elevations are
considerably lower than the left side tributaries, respond much more
quickly to early season temperature rises, and maximum flows are
generally in }~y or June. Winter flows are dependent upon ground water
storage, and in some of the smaller tributaries, the streams are
completely frozen during part of the year. Some water flows in the larger
tributaries during the entire year. Tanana River at Big Delta has a
remarkably well sustained winter flow, amounting to a minimum of about
4,000 cubic feet per second. Tanana River receives a large inflow
from ground water between Tok Junction and Big Delta. This amount
averages about 0.5 cubic feet per second per square mile during the
period of lowest flows. Minimum monthly flows on other streams in the
basin area range from O. 07 to 0.2 cubic feet per' second per square mile.
Estimates of average annual runoff indicate that unit runoff varies
from less than ten inches per year in the lowlands bordering Tanana
River to 32 inches on Nabesna River.
The following tabulation indicates the estimated average annual runoff
for selected streams.
Drainage Estimated average
Stream and location area annual runoff
sq. mile Acre feet C.F.S. Inches
Tanana River at
Big Delta 13,300 11,500,000 15,900 16.2
Nabesna River at .,"It>
Nabesna D.S. 1,910 3,300,000 4,600 32.4
Salcha River at
Salchaket 2,170 1,450,000 2,000 12.5
Chena River at
Fairbanks 1,990 1,330,000 1,840 12.5
Nenana River at
Healy 1,850 1,900,000 2,620 19.3
A complete tabulation of estimated average annual runoff as well as
estimated average monthly flows appears in Table 5.
Stream and location
Tanana River near Tok
Junction
Tanana River at
Cathedral D.S.
Tanana River at Tower
Bluffs D.S.
Tanana River at
Big Delta
Tanana River at
Nenana
Chisana River, 8 miles
below Cross Creek
Chisana River near
Northway
Nabesna River at
Nabesna D.S.
Salcha River at
Salcha D.S.
Salcha River at
Salchaket
Chena River at
Chena D.S.
Chena River at
Fairbanks
Totatlanika at
Totatlanika D.S.
Nenana River at
Nenana D.S.
Nenana River at
Yanert D.S.
Nenana River at
MCKinley D.S.
Nenana River at
Healy
Teklanika at
Teklanika D.S.
TABLE 5
Average Stream Flow
Drainage
area
sq. mile
Average annual runoff1 !
6,650
8,400
9,800
13 ,300
25,200
770
3,140
1,910
1,500
2,170
950
1,990
240
620
1,150
1,825
1,850
508
Acre-
feet
5,800,000
7,200,000
8,500,000
11,500,000
18,000,000
900,000
1,800,000
3,300,000
1,100,000
1,450,000
670,000
1,330,000
180,000
640,000
1,180,000
1,880,000
1,900,000
500,000
Second-
feet
8,000
9,900
11,700
15,900
24,900
1,240
2,500
4,600
1,520
2,000
925
1,840
250
884
1,630
2,600
2,620
690
Inches
16.4
16.1
16.3
16.2
13.4
21.9
10.7
32.4
13.7
12.5
13.2
12.5
14.1
19.3
19.2
19.3
19.3
18.5
l/Average annual runoff and average monthly flows are based on meager
hydrologic data and are derived principally from drainage area relationships.
Source: Harbors and Rivers in Alaska. Survey Report. Interim ~ort No.4.
Tanana River Basin. Corps of Engineers, North Pacific Division, Hay 1, 1951
Pg. 96A
97
Streams draining from the right limit of Tanana River all have fairly
uniform annual runoff and range from 11 to 13 inches. The headwater
areas of these streams yield slightly more than the lower portions, but the
difference is estimated to be not more than 20 percent. The average
precipitation on these streams is probably not greater than 15 inches
annually, which indicates that losses are very low and that runoff is
about 80 percent of the precipitation. Evaporation and transpiration
losses are low because of the short summer season and the stunted
growth of the vegetal cover. Since permafrost is prevalent throughout
the basin, very little water is lost to ground water and surface water
escapes quickly to the streams.
A greater range of unit runoff occurs on left side tributaries than
those on the right and accordingly, estimates of annual runoff from
streams originating in the Alaska Range on which no records exist are
more uncertain. Unit runoff varies from ten to 35 inches annually. In
general, higher unit runoff is expected from streams with larger percent-
ages of glacier area. On the average, slightly over 20 inches of runoff
annually flows from the mountainous regions of the Alaska Range, and the
lower reaches of these streams in Tanana River valley have approximately
ten inches of runoff.
Since stream flow records cover a period of from a few months to four
years, the only basis for estimating the variation in annual runoff is
obtained from precipitation data.
. ,
Hany of the streams heading in the Alaska Range are partially fed from
glaciers, whose annual runoff is fairly uniform over a period of years.
The glaciers tend to reduce the variations in annual runoff which would
otherwise result from periods of below normal precipitation. Variations
in annual runoff from those streams are estimated to vary from 70 to 135
percent of the average whereas those streams with little or no glacier
areas have larger extremes which are estimated to range from 65 to 150
percent of normal.
For streams in Tanana River Basin, floods are most commonly the result
of snowmelt runoff and may occur from May to August. Occasionally,
rain runoff may add to the peak, and in some cases rain may be the
primary cause of high discharges. Unusually warm temperatures at the
time of the spring breakup of ice causes high flows which may reach
flood proportions, and ice jams accompanying the breakup can aggravate
flood conditions. Snowmelt floods occur in the lower elevation basins
during Mayor June, but on the upper reach of Tanana River they generally
come later in the season because a larger proportion of the area lies
at high elevations which require warmer temperatures to produce flood
discharges.
Periods of high discharge are experienced on all of the rivers, but
because of the lack of development along the banks, no damage occurs
and they pass unnoticed. However, a severe flood problem exists wherever
improvements have encroached on the flood plain.
Another factor affecting floods is the sudden release of water stored
in or behind glaciers. While no floods of this type have been recorded
in Tanana River Basin, the potential danger of such an occurrence
should be recognized in any river system which contains large glacier
areas.
Lakes: The only large natural lakes on major tributaries within the
basin are Tetlin Lake on Tetlin River and Minchumina Lake on Birch River,
a tributary of Kantishna River. The total effect of their natural
regulation upon stream flow is small and may be neglected when considering
flows in Tanana River. Innumerable small lakes exist in Tanana River
valley and are a part of the extensive swamps that prevail in both the
upper and lower reaches.
Storage: Water storage is seasonal and limited. Few onstream lakes
provide storage sufficient help to sustain stream flow during winter or dry
summers. The snowpack provides most of the active water storage in
winter, as it retains all the precipitation during
winter, thus causing the annual low flow. Glaciers provide some over
year storage that helps sustain stream flow during dry years. Even
though the Tanana basin is widely underlain by permafrost, alluvial
aquifers near large rivers provide very significant water storage to help
sustain stream flow.
100
I'
Chemical Quality: In the Tanana basin nearly all of the surface water
is acceptable. Chemical quality in most of the concentrations of
analyzed samples range from 60 to 484 mgtl dissolved solids; however,
most of the analyzed water samples contain less than 200 mgtl dissolved
solids. The day to day dissolved solids concentration appears to be
highest in stream parts near the Alaska Range and Yukon-Tanana Uplands,
and to decrease toward the center of the basin. Streams near the center
of the basin appear to have highest concentrations of dissolved solids
during periods of low flow, probably because of seepage of ground water.
The streams flowing from the Alaska Range are generally somewhat higher
in sulfate and magnesium content than are the other streams but none
carry excessive amounts of these constituents. Iron is the only constituent
that is present in undesirable amounts in any of the surface waters.
Two samples show high iron content from swampy areas near the Canadian
boundary where iron may be complexed with organic material.
Lakes are both higher and lower in iron and in color than streams but the
hardness of lake water is generally less tlwn that of the stream's water.
Sediment: The Tanana River receives both its principal flows and its
largest sediment loads from streams draining the glaciers of the Alaska
Range and the Wrangell Mountains.
101
Samples from these streams indicate the normal summer sediment
concentrations probably range from 500 to 2,000 mg/l. In contrast the
nonglacial streams draining from the north into the Tanana River
carry only about ten to 300 mg/l.
Streams that originate at lower elevations on both sides of the Tanana
River probably carry only five to 50 mg/l of sediment. These streams
derive most of their suspended sediments from bank and bed erosion and
are constantly reworking the valley deposits.
The Nenana River main stem has been sampled periodically at four locations
along its course through the Alaska Range and into the Tanana valley and
apparently gains large amounts of sediment as it flows downstream.
Summer normal concentrations of this area range from ten mg/l in the
headwaters to over 1,000 mg/l downstream. Such variation may also be
present in other stream systems with headwaters in the Alaska Range.
Sediment concentrations are greatest during summer months. The particle
size distribution is different for glacial and nonglacial streams.
Samples indicate that 60% to 70% of the summer normal suspended sediment
size in the Tanana River is finer than 0.062 mm. Only about 50% of the
Nenana River's suspended sediment size at Nenana is finer tl'.an 0.062 nun.
JO~
Suspended sediment concentrations there decrease during the fall and
early winter and are generally less than 20 mg/l for all streams in the
basin from January through April.
Average annual suspended sediment yields in the basin vary from less
than 100 tons per square mile in the mountains north of the Tanana River
to perhaps 5,000 tons per square mile in the Alaska Range.
Existing Problems:
Flooding. Inundation of a large portion of the valley lowlands and bank
erosion, particularly in those areas contiguous to the confluence of silt
laden tributaries from the Alaska Range, is characteristic of the Tanana
River Basin. There is continued menace of encroachment on the right limit
of the main channel. The natural conditions responsible for this northward
migration are discussed under the subject of sedimentation.
The growth and development in and adjacent to Fairbanks has greatly
increased the potential damage which a major flood might cause. This was
realized in 1967 when a large portion of Fairbanks was flooded. Flood
control projects are currently underway in the city.
Floods in Chena River may occur either as the result of snowmelt runoff
during the spring shortly after the breakup, or from summer rains during
July or August. Ice jams accompanying the spring breakup may aggravate
flood conditions at that time of year.
J03
Outside of the Fairbanks area, the next largest damage from floods
occurs at Nenana. The town is located on low ground immediately
upstream from the confluence of the Nenana and Tanana Rivers. Principal
damage to date arises from flooding of homes, buildings, marine ways,
gardens, septic tanks, water supply, and rail facilities.
Water Supply. In the development of water supply for domestic use in
the Tanana Basin, several serious problems may be encountered.
Permafrost under much of the land restricts both surface drainage and
ground water movement and is very apt to affect adversely the quality of
underground water supply. Most surface waters are laden with silt and
would require treatment.
The larger communities and military installation have central water
supplies and distribution systems. Smaller communities depend upon
individual wells or surface supplies. Waste disposal is usually by
privie or cesspool. See Summary of Water Supplies at Alaska Communities,
1973. II Yukon Region, Tanana Subregion-
l/Summary of Water Supplies at Alaska Communities, 1973. Yukon Region,
Tanana Subregion, Alvin J. Feulner. Resource Planning Team, Joint Federal-
State Land Use Planning Commission. July 1973.
I D l/
Navigation: Navigation of the Tanana River is beset by difficulties
arising from the aggrading stream bed. Flowing as it does over a
broad bed of unconsolidated material and confined by low banks of the
same material, continual shifting of the river channels is induced by
fluctuations in flow. The ever changing water depths and channel
alignments are constanb threats to the safety of boats and cargo and
often require advance soundings by small pilot boats to assure safe
passage. Aside from possible damage, the principal result is time
lost.
Lack of sufficient tonnage and the fact that the haul is mostly one
way with very little back haul have hampered profitable operation.
Drainage. The large areas of land having agricultural possibilities
are in this subregion. These areas lie on or adjacent to the valley
floor of the Tanana and its tributaries where topography generally
permits good natural drainage or where drainage can be readily provided.
Several other areas of similar soil types and with a total acreage
exceeding that of the selected agricultural lands lie on the valley
floors. These areas, because of low relief, are lake studded and swampy
and would be difficult and costly to drain.
Permafrost is present throughout the basin and is found at varying
depths and in lenses. Where permafrost lies close to the surface, water
cannot percolate through the ground but must be removed by surface drainage.
The deep frost experienced during the winter acts in much the same manner
in its effect upon drainage.
105:
As the agricultural possibilities of this basin have attracted but few
people to date~ large areas of land with relatively minor or local
drainage problems remain unsettled. Until these lands are settled and
more agricultural land is demanded, major drainage improvement does not
appear to be needed.
Sedimentation. Development of the water resources of the Tanana Basin
will have to take into consideration the problems created by the
heavy loads of sediment transported by most of the streams in this area.
In the development of storage for power or flood control~ the effect
of the deposition of this sediment must be studied. The general solution
to this problem lies in the provision of sufficient storage capacity to
store the silt trapped during the expected life of the project without
encroachment upon the usable storage. The extra height of dam generally
required for this purpose will add to the cost of the structure and so
affect its economics. The expected life of hydraulic machinery subjected
to abrasive action of fine silt might be reduced and thus affect the
economics of projects utilizing flow from glacial streams.
The shifting bed material~ from upstream points to aggrading points below~
causes frequent channel changes which pose a major problem for both flood
control and navigation. Navigation is obviously a difficult process when
channel changes are so rapid that a channel which is passable on an out
trip may be blocked on the return.
....
Construction to stabilize channels would require almost constant
maintenance, and in order to make the stabilization locally successful,
it would be necessary to maintain gradients and capacities sufficient
to prevent deposition harmful to the improvement. A gradient sufficient
to accomplish this purpose during flood flows would disturb the
regimen of the river and increase the potential problems both upstream
and downstream.
Ice. The exposure of Tanana Basin to the dry, cold mass of continental
air that stagnates over the interior of Alaska during the winter causes
severe freezing. With average monthly temperatures at Fairbanks ranging
from minus 11.3° to 29.4° Ffor seven months of the year, thick sheets
of ice are formed on the lakes and streams of the area. While shallow
lakes and smaller streams are solidly frozen, deeper lakes may freeze
to depths of five feet, and ice thicknesses of four feet are common on
streams. As streams freeze they sometimes become clogged by frazil and
anchor ice which causes flooding both above and below the obstruction
and this freezing aqds to the thickness of earlier ice formations. On
navigable streams, the pending formation of an ice cover means the
cessation of all navigation for the season. The ice usually begins to
form about the middle of October on the larger streams and generally
remains until the first week in May. During the winter, the frozen streams
provide crossings for sled roads, winter trails, and ski plane landing
areas for isolated operations.
, 07
The major ice problem develops with the spring breakup. Structures,
along the rivers, which have endured the forces created by expansion
and contraction of the ice sheet during the winter must then withstand
the abrasion and impact of large masses of ice moving. This condition
is aggravated by the embedded materials such as sand, gravel, rocks,
and snags which have adhered to the ice. Where constrictions occur
along the channel, this ice often jams to form dams which cause flooding
and exert tremendous forces on structures that cause the jam or may be
in its path as it breaks and moves downstream. Large volumes of ice are
forced out of the streams at times and may crush or move structures in
its path.
Permafrost. In common with other far northern areas, much of the ground
in Tanana Basin is permanently frozen to depths varying to more than
200 feet. This frozen condition of the soil, permafrost, is believed to
have originated during the ice age when regional temperatures were lower
than at present. As previously indicated in the climatological discussion, ' ..
the present average annual temperatures of the lower areas in the basin
are below freezing and range from about 23° F to 30° F. This low
temperature together with the insulating effect of the vegetative cover
has retarded thawing of the permafrost. However, adjacent to the major
streams the banks, which are composed of open sands and gravels, have .,.,
been thawed for distances of several hundred feet. Other areas are also -thawed to considerable depths or may have only occasional frozen zones.
. /" ()
'" ' .. :
...
...
,,'
...
Permafrost occurs as frozen soil or rock and at times as solid ice
lenses containing very little soil matter. When the surface covering
of insulating growth is removed as in foundation preparation for
structures or farm operations, progressive thawing proceeds and causes
differential settlement as various materials are consolidated. Sands,
silts, and clays become very unstable and show extensive consolidation,
while gravels are consolidated to a limited extent by thawing, but
solid rock remains relatively unchanged.
Large volumes of gold bearing gravels have been thawed in mining
operations and at times have been allowed to remain for several years
before processing. Upon excavation it was found that the material had
refrozen only in the zone of contact with unthawed material •
The preparation of foundations for structures in permafrost areas poses
problems which require special treatment to insure against failure.
Treatment generally consists of either controlled thawing and consolidation
prior to construction or complete prevention of thawing by insulation,
or even the use of mechanical refrigeration.
Stream Pollution. A 1950 report of the Corps of Engineers reports:
"The turbidity is increased below some of the mining operations on
the stream which are relatively clear but it is not noticeable on
those streams which already carry a heavy sediment load".
Mining within the general area is almost nonexistant at this time. Recent
environmental protection legislation should preclude these problems.
To the extent that municipal or other waste products are still entering the
streams on a raw basis, there is a problem.
Potential for Water Resource Development
Water Supply: Most of the water pumped in the Tanana Basin area
ground water is supplied from wells for municipal, industrial, military,
and domestic supplies; small amounts have been developed for
irrigation, although the wells are known to have been drilled specifically
for irrigation. Fairbanks is the only basin community having a municipal
water supply system, although several military installations have
extensively developed systems. The largest supplies of ground water
are presently obtained from city wells and those at military establishments
near the southeast of Fairbanks, where pumpage is estimated to be about
11 to 12 mgd. Of this total about 7.5 to 8 mgd are used by the military;
Fairbanks uses approximately 2.0 and 2.5 mgd; and the remainder is
used by smaller communities throughout the area.
Surface water is little developed. although large quantities exist.
Most surface water contains glacial silt and flour during summer months.
Infiltration galleries or drilled wells installed adjacent to the
larger streams could supply silt free water in large quantities, if
needed.
Much of the ground water is high in iron and organic content and requires
treatment before most uses. The procurement, treatment, and distribution
of water supplies, as well as the disposal of wastes, are handicapped by
low air, ground, and water temperatures.
, : ')
I~
-
The undeveloped potential of the basin water resources use is large.
The lowlands adjacent to the Tanana Basin and extending up other streams
could yield 1,000 to 5,000 gpd of drilled wells. Surface water supplies
are nearly undeveloped. Several sites having hydroelectric power
potential have been located.
Although ground water development is more intense in the Fairbanks
area than in any other of the northern parts of the state, present use
(1969) is only a fraction of the potential available for future
development. Thepotential yield at the area should be in excess of
100 mgd.
The development of a reliable potable water supply and distribution
system is needed by most villages. Its concomitant of sewage collection
and disposal will become even more important with increasing population.
Several potential water storage sites have been identified in the area.
These are shown on the 1:250,000 and Map 11. Also see reports:
Summary of Water Supplies at Alaska Communities, 1973.
Flood Control: The List of Urban Places -Flood Hazard,prepared by the
Alaska District, Cor~s of Engineers indicates that many of the villages
along the Yukon-Tanana are subject to some degree of flooding. Ice
jams and stream overflow appears to be the major cause of flooding with
erosion of the riverbanks a secondary problem.
III
Q P, ..... ,."I Wol .. 51". Si'"
-;.> f'o' .. "IIQI H,dtccl .. ctric Sil.
I! "",'\' I Por .. "",,1 Canol Si'.
",I
~;r.,-,';....... ___ -64 0
;\:
",I
I~
:\:
... I -," ~\
Mopll
\ 12.
While floods are an annual occurrence in the Tanana Basin, resulting
damages have, in general, been slight except in Fairbanks because
of the limited developments in the area. Along the upper reaches
of the streams, the only structures are the main highways and the
railroad, and protection of these is essentially a maintenance problem.
Most settlement, with attendant encroachment upon the flood plain of
the streams, has occurred in the lower reaches of the streams. At
these points high flood flows have caused or threatened damage by
direct inundation, by bank erosion, or by major channel changes. To
date, the most serious flood damage has occurred in and adjacent to
Fairbanks although damage has been significant at Nenana, Eielson
Field, and Big Delta Air Base.
At least three alternatives are available to assist in protection
of life and property:
1) development of "new towns" outside the flood plain,
2) local protection works, such as levees and bank stabilization, and
3) control of the flow of the river(s) via dams and impoundments.
Numbers 2) and 3) are often difficult to justify on economic grounds for
smaller communities. Number 3) will be further discussed under Power.
A flood protection project is currently underway at Fairbanks.
Navigation:l / Navigation upon the Yukon River system has played a significant
part in the development of the interior, although the dependence of the
Tanana Basin upon river navigation has materially decreased since land
liThe following discussion is taken from the Corps Study previously referred to.
Specific attention is called at this point to the 1951 date of the study.
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transportation has been provided. Much of the interior, however, still
depends upon navigation on the lower Tanana River. There, navigation
is beset with many difficulties.
The major part of the economic development of the basin has been
confined to Fairbanks and adjacent areas. In this immediate vicinity,
also, has been constructed one of the major military bases for the
defense of Alaska and of the continent. Thus Fairbanks, in addition to
its great importance as a trade and transportation center for the vast
interior assumed further importance as a military base.
The importance of river navigation in the Tanana River Basin to the
outlying areas of the interior as well as the difficulties attending
navigation are significant. Until other means of supplying these
outlying areas are developed and a dependable service provided, river
navigation must be maintained.
The Tanana River from its mouth to Chena River at mile 201 is utilized
by navigation interests to move freight. Only a small amount of local
freight is moved in the reach above Nenana. The larger equipment
operates from the rail port at Nenana to the Yukon and serves communities
and installations along the Yukon. At present, considerable hazard
exists at several locations because of the distributary channels which
reduce the amount of water carried by the main channel and by the braided
character of the stream at some of the wider sections.
) ) ~ i
Channels throughout these reaches are continually shifting and do not
permit drafts of more than 3 3/4 feet even during higher stages.
On the basis of a reconnaissance study of the lower reaches, the
more troublesome locations could probably be corrected by the judicious
use of permeable dikes and continued maintenance dredging. Though
located in sheltered locations, these dikes would probably have a
useful life of less than ten years. The annual costs therefore would
be high. In addition, dredging would be required throughout the
navigation season.
Even with a minimum amount of dredging, possibly 250,000 cubic yards
annually, the maintenance of a complete dredging unit in the area
would be necessary. This unit could be active for about five months
of the year, and the probable annual cost of dredging would also be high.
Benefits which would be derived from provision of navigation improvements
on the Tanana River are composed of operational savings resulting
from elimination of delays and hazards at channel crossings, making
multiple barge handling possible, and permitting the loading of vessels
and barges to full capacity.
Irrigation: Very little is known of the benefits which might be
derived from irrigation in the Tanana Basin. The deficiencies of climate
which is semiarid with annual precipitation of about 12 inches greatly
limit the agricultural possibilities of the area. The precipitation is not
only light, but its distribution throughout the growing season is not
conducive to best plant development.
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During the spring, when moisture is needed to sprout seeds and promote
rapid plant growth, little rain falls, and in the late summer and
fall when dry weather is required to mature and cure crops, precipitation
is apt to be excessive.
Irrigation might be beneficial in overcoming the effect of spring
drouths. It might also lengthen the effective growing season by inducing
earlier seed germination and speeding development. On the other hand,
the low temperature of surface and subsurface water available for early
spring irrigation might well retard rather than hasten sprouting. The
overall effect of irrigation upon total yield, maturity, and quality of
various crops requires thorough investigation before necessity and
feasibility of irrigation can be established.
Should irrigation be found beneficial, storage of water would not be
needed. Water is readily available for most areas with agricultural
possibilities by gravity diversion or by pumping from the Tanana or Chena
Rivers. The application of irrigation water would require careful control
to avoid a drainage problem.
Power: Several sites in this region have been identified as having
potential for major hydropower production and flood control. Eight
Junction Island, Bruskasna, Carlo, Healy, Big Delta, Gerstle, Johnson
and Cathedral Bluffs, are within this subregion. See Map 11.
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The potential Junction Island dam and 474,000-kilowatt powerp1ant would
be on the Tanana River, 91 river miles from the mouth. The site is 11.5
miles upstream from Junction Island and four miles below the mouth of the
Kantishna River. The Tanana River drains an area of 42,490 square miles
above the dam site.
Permafrost is present in the drainage basin.
The reservoir would be formed by the construction of an earth dam
across the Tanana River. The dam would have a structural height of
160 feet from the base at elevation 260 to the crest at elevation
420. The dam crest would be 145 feet above the river and have a length
of 16,000 feet.
The Junction Island Reservoir would contain a total of 59,000,000
acre-feet of storage capacity with the normal maximum water surface
at elevation 400. The active capacity of the reservoir would be
29,000,000 acre-feet after deducting sediment and dead storage allo-
cations. This amount of storage would be sufficient to fully regulate
the flows of the Tanana River for power production. Average tai1water
was assumed at elevation 275, resulting in a net average head of 114
feet. The development as discussed above, assuming an efficiency of
110 114'("1'111'. w,jl,ld II!' ('1111'11111' II' prodlll'lng It,f',OI)(I ~ 1 LuwattFl or ('ontlnllOllS
power. The installed capacity of the proposed plan would be 532,000
kilowatts.
117
Approximately 120 miles of the Alaska Railroad would require reloca-
tion from the reservoir area along with an estimated 600 people, largely
from the villages of Minto, North Nenana, and Nenana.
The Bruskasna dam would be the upper unit of the three dam upper
Nenana River system. The Carlo and Healy sites are the respective
downstream sites.
The dam and power plant would be on the Nenana River about 107 miles
from the mouth and approximately one mile above Bruskasna Creek.
The drainage area above the same site is 650 square miles. The lower
portions of the basin contain stands of timber, while the upper
elevations are almost devoid of vegetation. The river above the
dam site has a braided channel in much of the drainage basin. Portions
of the reservoir area are now swamps. Permafrost conditions are to
be anticipated in much of the drainage area.
Based upon stream flow records for the Nenana River near Windy, the
average annual stream flow at the dam site was estimated at 826,000
acre feet.
The 50 year sediment allocation at this site was estimated at 30,000
acre feet based upon sediment observations in the Nenana River Basin.
The 50 year sediment production for the three dam systems was estimated
at 125,000 acre feet distributed between the various reservoirs.
"
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The Bruskasna reservoir would have a normal maximum water surface
at elevation 2,330. Partial regulation of the Nenana River stream
flow would be achieved through the system operation of the three
plants; Bruskasna, Carlo, and Healy. The installed capacity of the
plant would be 40,000 kilowatts and the continuous power capability
of the three dam system would be 95,900 kilowatts.
A concrete arch dam across the Nenana River would have a maximum
structural height of 305 feet from the base at elevation 2,030 to the
crest at elevation 2,335. The dam crest would be 255 feet above
the river. The crest length of the dam would be approximately 1,200 feet.
There is a 21,100 acre withdrawal for thi~ site.
The Carlo dam and power plant would be the middle unit of the three
dam upper Nenana River system. The Healy site lies downstream and
the Bruskasna site is upstream.
The dam and powerplant site is on the Nenana River about 74 miles
from the mouth and 15 miles upstream from the Healy site. The site
is near Mile 342.5 on the Alaska Railroad.
The drainage area above the dam site is 1,190 square miles. The
lower elevations of the basin support stands of timber, while the upper
elevations are almost devoid of vegetation. Permafrost conditions exist
in portions of the drainage area •
Based upon data on sediment samples obtained in the Nenana River
Basin, the 50 year sediment accumulation for the system was
estimated at 125,000 acre feet. The 50 year sediment accumulation in
the active portion of the Carlo reservoir was assumed to be
7,000 acre feet.
Nenana River stream flow is estimated at 1,670,000 acre feet.
The Carlo Reservoir would have normal maximum water surface at elevation
1,900. Partial regulation of the Nenana River flows would be obtained
by the operation of the three plants, Healy, Carlo and Bruskasna,
as a system. Capacity of the power plant would be 30,000 kilowatts and
the continuous capability of the three dam system would be 95,900
kilowatts.
The reservoir would be formed by a concrete arch dam across the
Nenana River, with the crest 205 feet above the river. The dam
crest would be at elevation 1,905 and the base at elevation 1,650
for a maximum height of 255 feet. The crest length of the dam
would be about 800 feet.
The Healy dam and power plant would be the lowest unit in the three
dam Upper Nenana River System.
The dam and power plant would be built at river mile 59 on the Nenana
River. The site is near Mile 354.5 on the Alaska Railroad.
The river has a 1,900 square mile drainage basin above the dam site.
The basin lies in the heart of the Alaska Range. Stands of timber grow
on the lower elevations, while the higher portions of the basin are
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almost devoid of vegetation. Permafrost conditions exist in
areas of the basin.
Based upon recorded flows, the average annual stream flow at the
dam site was assumed to be 2,675,000 acre feet per year.
The Healy Reservoir would have a normal maximum water surface at
elevation 1,700 feet. Partial regulation of the Nenana River
flows would be obtained by the system operation of this site and
the upstream Carlo and Bruskasna reservoirs. The installed capacity
of the power plant would be 130,000 kilowatts. However, the
continuous capability of the system would be 95,900 kilowatts.
The reservoir would be formed by the construction of a concrete
arch dam across the Nenana River. The dam would have a maximum
structural height of 405 feet from the base at elevation 1,300
to the crest at elevation 1,705. The crest length would be
1,300 feet. The crest of the dam would be 355 feet above the river.
Approximately 18 miles of the Alaska Railroad would have to be
relocated.
The Big Delta dam and power plant would be on the Tanana River
300 miles upstream from the mouth. The sight is immediately down-
stream from the confluence of the Tanana and Delta rivers.
The Big Delta Reservoir capacity would provide 90 percent regulation
of the Tanana River flows for power production. The proposed plan would
develop 113,000 kilowatts of continuous power. The installed capacity
of the plant would be 205,000 kilowatts.
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The reservoir would be formed by an earth dam across the Tanana
River. The dam would have a maximum structural height of 150 feet
from the base at elevation 970 to the crest at elevation 1,120.
The dam crest would be 140 feet above the river. The crest length
would be approximately 2,400 feet.
Approximately 400 people would have to be relocated from the
reservoir area.
The Gerstle site would operate in conjunction with the upstream
Johnson site. The Johnson site would provide regulation for the
system. The Gerstle dam and 76,000 kilowatt power plant would
be on the Tanana River, 368 miles upstream from the mouth. The
site is approximately two miles below the mouth of the Gerstle River.
The drainage area is 10,700 square miles above the dam site.
Permafrost conditions exist in the area.
The average annual runoff at the Gerstle dam site was estimated at
8,000,000 acre feet.
The Gerstle site would operate as a run of the river plant with the
reservoir water surface at elevation 1,290, coinciding with the
Johnson site tailwater elevation. The upstream Johnson Reservoir would
regulate 96 percent of the Tanana River flows at the Gerstle site for
power production. The proposed project as outlined above would be
capable of producing 42,000 kilowatts of continuous power. The
installed capacity would be 76,000 kilowatts.
Approximately ten miles of road would have to be relocated or
constructed to provide access to the project. Construction cost
per installed kilowatt = $1,600.
The Johnson site would provide the regulation necessary for the
development of the downstream Gerst1e site. The dam and power
plant would be on the Tanana River, 37~ miles above the river
mouth. The dam site is just below the confluence of the Johnson
and Tanana Rivers.
The drainage area above the dam site is 10,450 square miles.
The average annual stream flow at the Johnson site was estimated
at 7,830,000 acre feet.
The Johnson Reservoir would have a normal maximum surface elevation
of 1,470. This capacity would provide 97 percent regulation of the
Tanana River flows for power production.
The development of this site as outlined above would be capable of
producing 105,000 kilowatts of continuous power at an assumed
efficiency of 80 percent. The installed capacity of the proposed
plan would be 191,000 kilowatts.
It was estimated that about 50 miles of road and pipeline in
addition to 100 people would have to be relocated.
The Cathedral Bluffs dam and power plant would be built on the Tanana
River at the town of Cathedral Rapids, 420 miles upstream from the
mouth. The dam would be built in a constricted section of the Tanana
valley at Cathedral Bluffs.
Because of the absence of bedrock in the left abutment, this
location is geologically unsuitable as a site for a concrete dam.
The suitability of the reservoir site is also doubtful due to the
highly permeable nature of the materials comprising the left
abutment area.
The drainage area above the dam site is 8,550 square miles. The
Tanana River Basin lies south of the Yukon River and north of the
Alaska Range. Permafrost conditions exist in the drainage basin.
The stream gaging station "Tanana River near Tanacross" is
approximately 1/4 mile downstream from the damsite. The average
runoff based upon ~ecorded flows is 5,800,000 acre feet.
The 50 year active storage sediment depletion in the reservoir
was estimated at 400,000 acre feet. Full regulation of the flows
at the dam site could be achieved with an estimated 4,900,000 acre
feet of storage. The development at 80 percent efficiency could
produce 79,000 kilowatts of continuous power. The installed
capacity would be 144,000 kilowatts.
Approximately 400 people would have to be relocated from the reservoir
area, mainly from the town of Tanacross and Tok Junction. About 70
miles of highway and pipeline would also have to be relocated.
Recreation in the basin is becoming a major industry and is beset by
many problems, but such problems are primarily those which face any
new and growing industry. The principal need is for additional roads,
..
trails, landing strips, hotel and lodge accommodations, and improve-
ments of boating and other recreational facilities. Any of these
facilities that might be provided in connection with water
resource development would be inconsequential in respect to the
overall needs of the industry.
Tanana River and most of its tributaries support runs of anadromous
fish which are of sufficient significance to warrant special
consideration in planning water use improvement programs. These
runs composed of chum, king, and coho salmon are known to migrate
upstream to their spawning grounds from shortly after the ice breakup
to well into the summer months. Resident grayling also migrate to the
headwaters of the smaller tributaries to reproduce. River improvements
which might possibly block or impede fish migrations should provide
means for the passage of fish.
Wildlife is of commercial significance to the Tanana Basin in that
it brings many sportsmen into the area, provides recreation for
local residents, and furnishes an income to guides and trappers.
Preservation, management, and proper utilization of this resource
is of primary importance.
However, if in the future construction of reservoirs should become
feasible, some feeding and nesting areas might be inundated. Under
such circumstances, thorough investigations would have to be made
by the Fish and Wildlife Service and the Department of Fish and
Game to determine the full effect such construction might have on
wildlife and what corrective measures might be required.
VIII Upper Yukon-Canada
Existing Situation
General: The Upper Yukon-Canada Subregion includes a portion of the
following physiographic sections: Yukon-Tanana Upland, Alaskan Range,
Eastern Part, Duke Depressions and Wrangell Mountains.
This subregion is generally a mountainous region whose streams flow into
the Canadian portion of the Yukon River.
Only limited information is available for this specific subregion. The
reader is referred to the discussion of the Upper Yukon and to Table 1,
of this report, additional information is available in Resource Planning
Team Report: Summary of Water Supplies at Alaska Communities, 1973. Yukon
Region, Upper Yukon-Canada Region by Alvin J. Feulner.
Existing Problems
Again, little information is available; however, one may assume from the
topography that spring runoff provides ample opportunity for stream overflow
flooding. See Map 10.
Developed water supplies are undoubtedly lacking.
Neither of the above problems should pose much difficulty as the population
is quite low. The 1970 census did not report a population for any of the
towns listed on the USGS maps.
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Potential for Water Resource Development
The only two items to be discussed herein are two potential power sites.
One, Forty Mile, is located within the subregion. The other is Yukon-
Taiya and is located in canada near the headwaters of the Yukon River.
The potential Forty Mile Project is about six miles upstream from the
canadian border. The project could provide a significant amount of power
and furnish any water supply or flood control that might be needed within
the Forty Mile Basin below the project. See Map 11.
The drainage area above the project is about five percent of the Yukon
Ba~in above Eagle, thus the project's role in broader plans for the Yukon
Basin would be relatively minor.
This project contemplates a concrete arch dam raising the water surface
to elevation 1,550 feet, or about 390 feet above the present water surface.
Estimated firm power potential is 166,000 kilowatts at 50 percent annual
load factor with firm energy of 723 million kilowatt hours per year.
Such a plan would involve a reservoir area of about 23 square miles,
inundating about 20 miles of the Forty Mile River and extending 14 miles
up the North Fork and 18 miles up the South Fork. An arm of the reservoir
near the dam site extends six miles up O'Brien Creek.
Likely project effects on fish and wildlife and other resources remain to
be evaluated. The project would involve minor relocations, including a
portion of the Taylor Highway.
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Value of the project for power is probably on the order of $10 million per
year. Any decision to build would depend on future developments in the
area.
Though it is identified as one of the more favorable of Alaska's hydro
potentials, the Forty Mile Project would likely not be justifiable as a
single purpose power development.
Studies have not been made of the benefits that might result from development
of the project under appropriate multiple purpose plans.
The project is thus considered to have sufficient value to merit consideration
in long range plans for the Forty Mile Basin, but of relatively low priority
in terms of broader regional needs.
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The headwaters of the Yukon River lie in northwest Canada and form a series
of large lakes at about elevation 2,150 and within 20 miles of tidewater in
southeastern Alaska. The potential Yukon-Taiya Project would provide for
diversion of those headwaters and development of the hydro potential almost
at tidewater near Skagway, Alaska. It is one of the most favorable major
potential developments from the standpoints of indicated power production
costs and fish and wildlife effects. However, it would require negotiation
of international agreements to permit the regulation and diversion of flows
of the Upper Yukon River Basin in Canada and development of the potential
power in Alaska. The location of the power plant would be favorable from
the standpoint of accessibility for deep water navigation and to potential
power users in the Southeast Region. However, it would be more distant
than other major hydroelectric potentialities from the power load areas
of the Railbelt Area and Prince William Sound. The potential development
would not cause any major adverse fish and wildlife problems, though it
would involve the spawning areas of salmon runs of international concern.
The runoff records of the Yukon River at Whitehorse and Hootalingua and of
the Teslin River near Teslin, indicate a critical period from 1902 to 1924
with an average annual runoff of 5,250,000 acre feet, compared to an average
annual runoff of 6,100,000 acre feet for the period 1943 through 1960.
Nearly continuous discharge records for the Yukon River at Hootalingua for
the period 1953 through 1960 indicate an average annual runoff of 7,820,000
acre feet.
Eleven years of interrupted discharge records of the Teslin River near
Teslin over the period 1944 through 1960 indicate an average annual runoff
of 6,994,000 acre feet at the mouth of Teslin Lake.
The plan would involve construction of a dam at the Hootalinqua site on
the Yukon River to control the flows of the Yukon River at the dam site to
elevation 2,200 feet above mean sea level, channel improvements and a
tunnel to permit diversion of the controlled flows from Lindeman Lake
under the Coast Mountains, penstocks and a power plant near Skagway, and
a transmission system to deliver the project power to appropriate load
centers in Alaska.
The Hootalingua dam would be located just below the confluence of the
Teslin River with the Yukon River where the mountains form a narrow gorge.
On the basis of available geologic data and the dam site characteristics,
the reconnaissance design and cost estimate contemplates a concrete
gravity dam.
The dam would have a maximum height above stream bed of about 430 feet.
The dam crest would be at elevation 2,210 feet above mean sea level and
have a total length of about 2,200 feet. The dam would raise the water
surface at the site about 230 feet to a top of conservation elevation of
2,200 feet, which is about 50 feet above the normal water surface of the
Tagish-Marsh chain of natural lakes. The reservoir at full pool level
would extend up the Teslin River to about 13 miles below Teslin Lake and
would have a surface area of about 720 square miles. The major portion
of the reservoir area consists of the existing lake system. The reservoir
would be quite narrow in the general shape of an inverted vee and would
have a length of about 80 miles up the east or Teslin leg and 180 miles
up the west or Yukon leg.
The reservoir would have a total capacity of 31,000,000 acre feet with
the pool level at elevation 2,200 feet.
The water supply estimates assume reservoir release to maintain a minimum
flow of 1,500 cubic feet per second in the Yukon River below the dam and
indicate an average reservoir yield of about 1,350,000 acre feet annually
or 18,500 cubic feet per second.
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The plan contemplates relocation of that portion of the city of Whitehorse
below elevation 2,200 feet. About 40 miles of highway and 40 miles of
narrow gauge railroad would be relocated.
Existing channels would be deepened and improved in three locations to
,~
provide necessary flows at low reservoir levels. The locations of the
required channelizations are (1) Atlinto River draining Atlin Lake,
(2) Lindeman Creek Channel draining Lake Lindeman, and (3) Channel through
Nares Lake.
A 36 foot diameter, concrete-lined pressure tunnel, 17 miles long would
divert from Lake Lindeman, which would be the headwaters of the reservoir.
The tunnel will cross through the Coast Range Mountains and terminate above
the power plant on Taiya River •
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On the basis of an average diversion of 18,500 cubic feet per second and
an average power head of 1,913 feet, the power plant would have a prime
.. capacity of 2,400,000 kilowatts and would generate 21.0 billion kilowatt
hours annually. The power plant would have an installed capacity of
3.200,000 kilowatts with a 75 percent plant factor.
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