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This electronic copy of the report includes the revised pages that were
distributed in the Sept. 19, 1960 memorandum: p. 3, p. 4, and p. 25.
UNITED STATES DEPARTMENT OF THE INTERIOR
F I S HAN D WILDLIF ESE RVICE
ARNIE J.SUOMELA,COMMISSIONER
O'EVIL CANYON PROJECT
SUSITNA RIVER BASIN
ALASKA
S
9 64
:A .U62
. I I A L!2
.
~·D;.'·R ~E":P O R ·T ON THE FISH AND WILDLIFE RESOURCES
I ..•.
I,t :,..~---....:.------'
United States Department of the Interior
Fish and Wildlife Service
Bureau of Commercial Fisheries
Juneau,Alaska
A Detailed Report on Fish and Wildlife Resources
affected by the
DEVIL CANYON PROJECT
Alaska
Branch of River Basin Studies
May 1960
UNITED STATES
DEPARTMENT OF THE INTERIOR
FISH AND WILDLIFE SERVICE
BUREAU OF COMMERCIAL FISHERIES
BOX 2021
JUNEAU.ALASKA
ALASKA REGION
(REGION II)
ADDRESS ONLY
THE REGIONAL DIRECTOR
May 2,1960
Memorandum
To:
From:
Subject:
District Manager,Bureau of Reclamation
Juneau,Alaska
Regional Director,Bureau of Commercial Fisheries
Juneau,Alaska
Regional Dire ctor,Bureau of Sport Fisheries and Wildlife
Juneau,Alaska
Devil Canyon Project,Susitna River Basin,Alaska
This is our detailed report of our studies concerning effects of the
Devil Canyon Project upon the fish and wildlife resources.Both
facilities of the project,the Devil Canyon Darn and Reservoir and
the Denali Darn and Res ervoir,are located in the Susitna River
Basin of south-central Alaska.This report has been prepared in
accordance with the Fish and Wildlife Coordination Act,48 Stat.
401,as amended;16 U.S.C.661 et seq.
We have studied the fish and wildlife re sour ce s In conne ction with
this project for effects as well as with a view toward mitigating
those losses which may result from project construction and oper-
ation.Further,we have explored the possibilities for enhancement
of these resources.This letter,which briefly summarizes our
findings and contains our recommendations,is supported in detail
by the attached substantiating report.
Big game,small game,fur animals,waterfowl,and both resident
and anadromous fish will be affected by project construction.Ap-
proximately 61,000 acres of land will be inundated,most of which
is moose range.Although the Nelchina caribou herd presently
utilizes the impoundment area as winter range,only about 33,000
acres is considered to be of good quality for this usage.Movement
patterns of the herd are such that it is believed the species will not
be seriously affected by project development and operation.
Some loss of small game and fur animal habitat is expected in the
project area.Harvest of these species,which is presently light,
due primarily to inacces sibility,may increase in adjacent areas
with project development as a result of improved access.
Some waterfowl nesting and rearing habitat will be destroyed by in-
undation.Similar habitat will probably not develop around the
reservoir perimeters due to fluctuating water levels.It is possible
that the two impoundments will receive more use by migrating
birds than the water bodies destroyed by inundation.
Fish present in the project area will be affected in a variety of
ways.Below the Devil Canyon and Denali damsites,alteration of
natural stream flow and temperature patterns will produce unknown
effects on the fish present in these areas.
At Devil Canyon,the planned operational releases are considered
adequate to preserve fish habitat.During the period of dam con-
struction,initial reservoir filling,and in the event of an unfore-
seeable cessation of power production,however,water releases
will be necessary to preserve the downstream fishery.Therefore,
a recommendation for minimum flows is made.These minimum
flows,as well as power flows during project operation,should be
released gradually to avoid flushing or scouring the channel.The
Susitna River below the Devil Canyon Dam serves as a migration
route for salmon ascending to the spawning tributaries.Releases
of water either colder or warmer than normal stream temperatures
could affect the attraction of salmon to such tributaries.The
Bureau of Reclamation should explore the feasibility of modifying
the intake structure to permit drawing water from selected temper-
ature strata in the Devil Canyon Reservoir.
Under proje ct operation,no wate r releases are planned from the
Denali Dam from about April to September of each year,depending
on runoff and power requirements.Stream dewatering in this sec-
tion could be deleterious to summer fish usage,However,it is
believed that fish populations here are minimal due to the turbidity
of the Susitna River.Also,this section of stream is located very
close to the headwaters and thus there are few tributaries above
the damsite to which fish movement may occur in summer months.
For these reasons,no minimum release during the period from
2
April through September, indusi ve 1 is requested from the Denali
Dam. Winter habitat will. probably improve in this area as a result
of increased flows. 1£ the Denali Reservoir proves to be reJ.atively
clear in the winter, enhancement of this area as fish habitat may
result. During the period of construction, initial. reservoir filling,
and project operation, a minimum flow is recommended from Octo
ber through March, inclusive, to maintain the downstream fishery.
These minimum flows, as well as the flows for power during project
operation,> should be releas ed gradually to avoid the flushing or
scouring of the channeL
Loss of stream habitat through inundation will be partially offset by
creation of two large reservoirs, However, the plan of operation
indicates rather wide fluctuations in the impoundment levels and
these fluctuations will probably limit fish production. Also, since
glacial silt tends to remain in suspen.sion, it is probable that these
waters will be turbid. The degree of turbidity is impossible to pre
dict at this time, although it may be generalized that the greater the
turbidity> the less productive the waters will be of fish life.,
Investigations of the Fish and Wildlife Service both above and below
the Devil Canyon damsite failed to reveal any evidence that anadro
mous fish migrate through or above Devil Canyon, Therefore, no
recommendation for a fish ladder or other fish passage device is
included. However, the possibility exists that the Louise, Susitna,
and Tyone Lake system, as well as certain other lakes in the basin,
could sustain a red salmon run, Also, the many clear-water
streams tributary to the Susitna River above Devil Canyon dalTIsite
may possess a potential for spawning and rearing of other salmon
ine species.. Additional studies to determine potential. spawning
areas are planned by the Fish and Wildlife Service in the future.
Should these studies indicate areas onable probability that the area
can be developed for production of anadromous fish, and should it
appear justified economically. then some type of fish passage
facility may be recommended for Devil Canyon Dam at a later date,
This report and the following recommendations have been endorsed
by the Alaska Department of Fish and Game as indicated in the
letter to us dated May 6. 1960 from Acting Commissioner Walter
Kirkness of that Department, a copy of which is appended to the
substantiating reporL
3
In order to minimize adverse effects to fish and wildlife resources
with project development and operation, it is recommended that:
1. During project development, reservoir filling and operation,
a minimum flow of not less than 2, 000 c. f. s. be maintained
at all times in the Susitna River below the Devil Canyon Dam.
However, should the initial reservoir filling occur during
the period October through April, inclusive, only 1, 000 c. f. s.
would be required.
2. During the period of construction, reservoi r filling and pro
ject operation a minimum flow of not less than 150 c. £. s. be
maintained in the Susitna River below the Denali Dam for the
period October through March, inclusive.
3. Abrupt changes in the volume of water discharged be avoided
at both dams; such changes should be made gradually or in a
series of slight increases or decreases.
4. The following language be incorporated in the recommendations
of the report of the District Manager of the Bureau of Reclama
tion:
a. tlThat additional detailed studies of fish and wildlife re
sources affected by the project be conducted as neces
sary after the proje ct is authorized in accordance with
the Fish and Wildlife Coordination Act, 48 Stat. 401, as
amended; 16 U. S. C. 661 et seq.; and that such reason
able modifications in the authqrized project facilities be
made by the Secretary as he may find appropriate to
conserve and develop these resources. "
b. tlThat Federal lands and project waters in the project
area be open to free use for hunting and fishing so long
as title to the lands and structures remains in the
Federal Government, except for sections reserved for
safety, efficient operation, or protection of public
property. tl
c. "That leases of Federal land in the project area reserve
the right of free public access for hunting and fishing. tl
4
5.The report of the District Manager,Bureau of Reclamation,
include the preservation and propagation of fish and wildlife
resources among the purposes for which the project is to be
authorized.
The analysis of project effects as set forth in the substantiating re-
port is based on engineering data available April 12.1960.The
Fish and Wildlife Service should be advised of any changes in
engineering plans so that the effects of such changes on the fish and
wildlife resources of the project area may be determined.
Very truly yours.
4t -{)rC/1t 1//fUftm-
URBAN C.NELSON
Regional Director
Bureau of Sport Fisheries
and Wildlife
5
a'~
JOHN T.GHARRETT
Regional Director
Bureau of Commercial
Fisheries
SUBSTANTIATING REPORT
TABLE OF CONTENTS
PREFACE
INTRODUCTION
Purpose of the Project
Location of the Project
DESCRIPTION OF THE AREA ...•.....•.........
Physical Features
Commercial Features
PLAN OF DEVELOPMENT
Engineering Features -Devil Canyon ....•..
Engineering Features -Denali .......•..••.
Operation -Devil Canyon ......•..•....•..
Ope ration -Denali .•....•.•..........•..•.
FISHERY
General _..'".."".,.,..
Without the Project -Devil Canyon .
Without the Project -Denali ..........•...
With the Project -Devil Canyon .
With the Project -Denali ......•..........
WILDLIFE .....•...................•..........
Without the Project -Devil Canyon .......•.
Without the Project -Denali ...........•.•.
With the Project -Devil Canyon ....••......
With the Project -Denali ..•..•...........
DISCUSSION
i
Page
1
3
3
3
4
4
7
9
9
9
9
12
13
13
13
15
17
17
19
19
20
22
22
24
LIST OF TABLES AND FIGURES
Page
Table 1.Engineering and Operating Data 12
Figure 1.Susitna River Basin Location (Map)5
Figure 2.Project Location (Map)10
Figure 3.Devil Canyon Damsite (Photo)11
Figure 4.Denali Impoundment Area (Photo)11
Figure 5.Schematic Map 14
Figure 6.Hydraulic Barrier to Salmon (Photo)16
11
PREFACE
1.This is a detailed report concerning the probable effects
of the Devil Canyon Project upon the fish and wildlife resources of
the project area.The overall project consists of two primary
features;the Devil Canyon Dam and Reservoir,and the DenaliDam
and Reservoir.These features are considered as separate facili-
ties throughout this report.Engineering data and operational
plans on which this report is based were obtained from the Bureau
of Reclamation on April 12,1960.
2.Fish and Wildlife field investigations have been conducted
intermittently in the project area since 1952 and,in part,concur-
rently with Bureau of Reclamation feasibility studies.The fish
and wildlife resources that will be affected by the Devil Canyon and
Denali features are discussed as they would probably exist without
and with project development.
3.No major water development project exists in a subarctic
location which will provide a basis for predicting the effect of the
Devil Canyon project on the fish and wildlife resources.Further,
only limited information concerning life histories and populations of
the various species involved is available.Thus,only generalized
predictions of project effects are possible.
4.App r e ci ati.on is expressed to the many members of the
various branches of the Bureau of Sport Fisheries and Wildlife and
the Bureau of Commercial Fisheries for supplying needed informa-
tion during the preparation of this report.
5.Since January 1,1960,the State of Alaska has assumed
control of the fish and wildlife resources of the new State.Staff
members of the Alaska Department of Fish and Game have indica-
ted a desire and willingness to contribute further information in the
continuation of studies of this project.
6.Previous reports prepared by the U.S.Fish and Wildlife
Se r vi ce that pertain to the Devil Canyon and Denali features are as
follows:
A Preliminary Report on Fish and Wildlife
Resources in Relation to the Susitna River
Basin Plan,Alaska.1952
1
A Progress Report on the Fishery Resources
of the Susitna River Basin,Alaska.1954
A Progress Report on the Wildlife Resources
of the Susitna River Basin,Alaska.1954
Progress Report,1956 Field Investigations,
Devil Canyon Damsite,Susitna River Basin,
Alaska.1957
Progress Report,1957 Field Investigations,
Devil Canyon Damsite and Reservoir Area,
Susitna River Basin,Alaska.1959
1958 Field Investigations,Denali and Vee
Canyon Damsites and Reservoir Areas,
Susitna River Basin,Alaska.1959
2
INTRODUCTION
Purpose of the Project
7.The purpose of the Devil Canyon Project will be to pro-
vide power to interior and south-central Alaska.Ultimate power
capacity of the Devil Canyon Project will be 580,000 kilowatts j
however,the initial capacity will be limited to 217,500 kilowatts.
Location of the Project
8.Devil Canyon Project,consisting of two dams and reser-
voirs,will be located in south-central Alaska,about midway
between the two population centers of Anchorage and Fairbanks.
More specifically,the Devil Canyon damsite is located on the
Susitna River 14.5 miles upstream from the Alaska Railroad sec-
tion at Gold Creek or at river mile 134.This development will
provide the source of power generation.The Denali damsite will
be located on the Susitna River at mile 248,or 15 miles below the
Denali Highway crossing of the Susitna River.The reservoir
formed by this dam will provide for water storage and regulation
of flows to be utilized downstream at the Devil Canyon site.
3
DESCRIPTION OF THE AREA
Physical Features
9.The Susitna River Basin lies in south-central Alaska,
north of the farthest inland projection of Cook Inlet between lati-
tudes 61 0
-64 0 north and longitudes 146 0
-153 0 west (Fig.1).The
total drainage of the basin comprises about 19,300 square miles of
relati vely uninhabited lands.The basin is bordered on the south by
the waters of Cook Inlet and the Talkeetna Mountains,on the east
by the Talkeetna Mountains and the Copper River plateau,and on
the west and north by the Alaska Range.
10.The main stem of the Susitna River from its source in
the Alaska Range to its point of dis charge into Cook Inlet is about
275 miles long.It flows southward from the Alaska Range for
about 60 miles;thence,in a general westerly direction through the
Talkeetna Mountains for about 100 miles,and then south for the
remaining 115 miles to its mouth at Cook Inlet.
11.Principal tributaries of the lower basin have as their
origin glaciers high in the surrounding mountain ranges.These
streams are for the most part turbulent in the upper reaches and
slower flowing in the lower regions.Most of the tributaries carry
a heavy load of glacial silt.
12.The Yentna River,one of the largest tributaries,begins
in the mountains of the Alaska Range,flows in a general southeast-
erly dire ction for approximately 95 miles and ente rs the Susitna
River 24 miles upstream from its mouth.
13.The Talkeetna River has its origin in the Talkeetna
Mountains.It flows in a westerly direction and discharges into the
Susitna River 80 miles upstream from its mouth.
14.The Chulitna River heads in the Alaska Range and flows
in a southerly direction,joining the Susitna River opposite the
Talkeetna confluence.
15.Principal tributaries of the upper Susitna drainage are
the Oshetna,Tyone,and Maclaren Rivers.For the most part,
these tributaries have numerous feeder streams that drain many
clear-water lakes.
4
,,2"
~
I
I
j
f A
I
'00'
,5<"
p
,...
c
Figure 1.Susitna River Basin ,Alaska
5
16.Stream flow in the Susitna Basin is characterized by a
high rate of dis charge from May through September and by low
flows from October through April.High discharges are caused by
snow melt,rainfall,and glacial melt.Streams carry a heavy load
of glacial silt during the summe r.During the winte r when low
temperatures retard water flows,streams are silt free.
17.The Alaska Range to the west and north,and the Talkeetna
Range to the east make up the high perimeter of the lower Susitna
River Basin.The Alaska Range is made up of sedimentary rocks,
some of which have been metamorphosed and intruded by granitic
masses.The Talkeetna Mountains are primarily granitic.The
floor of the lower basin is largely covered with glacial stream de-
posits.
18.The upper basin,predominantly mountainous,is bordered
on the west by the Talkeetna Mountains,on the north by the Alaska
Range,and on the south and east by the flat Copper River plateau.
Valleys are floored with a thick fill of glacial moraines and gravels.
19.The climate of the Susitna Basin is rather diversified.
The latitude of the region gives it long winters and short summers
with great variation in the length of the daylight between winter and
summer.
20.The lower Susitna Basin owes its relatively moderate
climate to the warm waters of the Pacific on the south and the bar-
riers of surrounding mountains.The summers are characterized
by moderate temperatures,cloudy days,and gentle rains.The
winters are cold and the snowfall is fairly heavy.Talkeetna,repre-
sentative of the lower basin,has an annual mean temperature of
33.2 of,,and an average annual precipitation of 28.85 inches.
21.The upper Susitna Basin,separated from the coast by
high mountains,has a somewhat more severe climate than the
lower basin.The nearest weathe r station at Mount McKinley Park
has an annual mean temperature of 27.5°F.,and an annual preci-
pitation of 14.44 inches.
22.Spruce,birch,aspen,cottonwood,willow,and alder
are found throughout the lower basin up to about 2,000 feet.These
are interspersed with low muskeg vegetation on the fl~or of the
6
basin and grassy meadows on higher benches.Understory of tim-
bered areas consists of moss,ferns,high and low bush cranberry,
devil's club,wild rose,blueberry,currants,grass,and wildflow-
ers.Above timberline,thickets of alder and willow occur inter-
spersed with grassy meadows.Above this zone vegetation consists
of moss,lichens,and wildflowers.
23.Spruce occurs throughout the upper basin up to the
2,500-to 3,OOO-foot timberline.Low,scrubby,black l!3pruce
grows on the poorly drained bottomland,while the larger white
spruce is found on bette r drained sites.Dwarf birch is distributed
throughout the upper basin,and willow occurs along water bodies.
White birch and alder occur in limited amounts.The understory
includes blueberry,low-bush cranberry,Labrador tea,crowberry,
fireweed,mosses,and lichens.Muskeg is interspersed throughout
the bottomland and tundra is present throughout better drained
areas.
24.Mount McKinley National Park,containing about 3,030
square miles and second in size only to Yellowstone National Park,
lies some 50 miles to the northwest of the project area.It -..:v:as
created by an act of Congress in 1917 and has as one of its objec-
tives the protection of the great herds of mountain sheep and cari-
bou in this portion of the Alaska Range.Mount McKinley,the
highest mountain in North America,is the principal scenic feature
of the park.This lofty peak rises 20,269 feet above sea level,
and soars some 17,000 feet above the surrounding forested plateau;
it is the only mountain in the world to rise so high from its own
base.
25,The Denali Game Reserve,extending from the north
side of the Denali Highway to the crest of the Alaska Range and
from the eastern boundary of the Maclaren River drainage west-
ward to a point 10 miles east of Cantwell,was established in 1957.
Currently,the reserve is closed to the taking of big game animals.
Commercial Features
26.The population of the basin is chiefly concentrated along
the railbelt with scattered settlements of trappers and miners
throughout the entire basin.The proposed project features are
located approximately midway between Anchorage and Fairbanks,
7
the two largest cities in the State.It has been estimated that these
two areas contain about 125,000 people or about 60 percent of the
entire State I s population.
27.The Alaska Railroad is the only overland means of trans-
portation through the lower Susitna River Basin.The Denali High-
way passes through the headwater portion of the upper Susitna
Basin.Although other secondary roads are being developed,
access to remote areas is still possible only by air and boat travel.
28.Economic activities are chiefly centered in the lower
100 miles of the basin along the r ai lbe l t,The commercial fishery
utilizing the Susitna salmon runs is located in Cook Inlet.Placer
and lode gold,tungsten,and construction materials are produced
in this lower area,but only in limited quantities.Coal and other
minerals are present but have received little attention due to high
development costs.Much of the basin is under lease by oil inter-
ests.Portions of the lower basin are sui ted for agriculture and
forest industries,which still await full development.
8
PLAN OF DEVELOPMENT
Engineering Features -Devil Canyon
29.Devil Canyon damsite,located on the Susitna River at
mile 134 (Fig.2),will be the initial development.The dam,
rising 635 feet above its foundation and 565 feet above the normal
water surface of the river (Fig.3),will be of a concrete-arch
design.Although the ultimate installed powe r capacity will be
580,000 kilowatts,the initial capacity will be 217,500 kilowatts.
30.The reservoir will be about 29 miles long and between
0.25 and 0.75 mile wide.At a normal full pool water surface
elevation of 1,450 feet,it will have a surface area of 7,550 acres
and an initial total capacity of 1,100,000 acre-feet.During a
l Otr-y e a r period,the average minimum operating pool level is
estimated at 1,284 feet rn,s ,1.At this level,the reservoir
would have a capacity of 205,000 acre-feet and a surface area of
about 1,900 acres.The dead storage pool will have an initial
surface area of 2,100 acres and a storage capacity of 293,000
acre-feet,at an elevation of 1,275 feet.
Engineering Features -Denali
31.The Denali Dam will be an earth and sand/gravel struc-
ture about 290 feet in height above the bottom of the cutoff trench
'---
and 219 feet above the river bed.It~location will be approximately
15 miles downstream from the Susi~rl.a River crossing of the Denali
Highway,or at river mile 248 (Fig"2).With normal full pool
water surface elevation of 2,552 feet,a reservoir 2 to 6 miles
wide and about 25 miles long will be created.This will cover
about 61,000 acres and store 5,400,000 acre-feet of water (Fig.4).
For a lOa-year period,the average minimum operating pool level
would be 2,484 feet rn , s ,1. ;at this elevation,the reservoir will
cover 34,000 surface acres and contain 1,650,000 acre-feet.
Initially,100,000 acre-feet of water will remain in the dead pool,
which will cover 300 acres at an elevation of 2,368 feet.The dead
pool storage will decline to zero over a lOa-year period,due to
sedimentation.
Operation -Devil Canyon
32.Maximum monthly power releases from the Devil Can-
yon Dam will occur during December when an average of 10,525 c.is.
9
F igure 2 .
Devil C a n yon Si te
Denali S ite
Project L oc a t io n Map
Z5 ZO 15 10 5 0 25 Mil..
bdbdb4 f
SCALE
......
o
N
\
\.
\
\
I!lZ"
I!lZ"
'l ...~'f.
~...~\O~...\.-
"...,+-\~'4
,,;~.
I!lO"·;r
/-/I
/'!.I
t.urr w lA..~i
1
~IlIl S No ~-.Jo £1 tJ-S+
SUSITN RIVER BASIN
U.S.B.R.Photo
Figure 3.View of proposed 0evil Canyon
0amsite,showing rapids and
river gorge.
Photo by Jack Lentfer
Figure 4'.Upper section of Denali impoundment area
looking north from Denali Highway bridge
crossing of Susitna River to headwater
glaciers ..
11
will be discharged.Minimum monthly power releases averaging
7,930 c.f.s ,will occur during July.The average annual release
will be 9,125 c.f.s.
Operation -Denali
33.Water will be stored in the Denali impoundment during
spring and summer for release in the fall and winter.Only incre-
mental flows will occur for about a six-month period in that section
of the Susitna River between the two impoundments.The month of
maximum discharge will be December when an average of 9,400
c.f.s ,will be released.The average release from the Denali Dam
during the period of operation will be 6,800 c.f.s ,
34.Salient features of engineering and operation are pre-
sented in Table 1.
TABLE I
PERTINENT ENGINEERING AND OPERATING DATA
DEVIL CANYON AND DENALI DAMS AND RESERVOIRS
1,450 2,552
7,550 61,000
1,100,000 5,400,000
1,284 2,484
1,900 34,000
205,000 1,650,000
1,275 2,368
2,100 300
293,000 100,000
7,930 -0-
(July 1)(April-Sept)
10,525 9,400
(Dec)(Dec)
9.125~1 6,800
(when re-
leases are
made)
Height of Dam (feet above foundation
and bottom of cutoff)
Maximum Pool Elevation (feet rn,s . 1. )
Surface Area (acres)
Storage Capacity (acre -feet)
Normal Full Pool Elevation (feet m s.L )
Surface Area (acres)
Storage Capacity (acre -feet)
Average Min.Op.Elevation(feet m.s.1.)
Surface Area (acres)
Storage Capacity (acre -feet)
Top of Dead Pool Elevation(feet rnv s i L]
Surface Area (acres)
Storage Area (acre-feet)
Average Min.Monthly Release (c.f.s , )
Average Max.Monthly Release (co f.s , )
Average Release (c.f.s , )
IIDoes not include spills
12
Devil Canyon
635
1,455
7,750
1,140,000
Denali
290
2,562
65,000
6,055,000
FISHERY
General
35.During the warmer months of the year,the Susitna
River is silt-laden throughout its entire course due to its glacial
orlgm.Sport fishing is thereby limited to the clear-water tribu-
taries and areas in the main Susitna River near the mouths of
these tributaries.The principal fresh-water sport fish present
in the Susitna Basin are rainbow and lake trout,Dolly Varden
char,and grayling.Other species of lesser importance are bur-
bot,sucker,sculpin,and two species each of stickleback and
whitefish.King,red,pink,chum,and coho salmon are found in
varying abundance in major tributaries of the Susitna River below
the Devil Canyon damsite.During the past 10 years,the first
wholesale value of the Cook Inlet salmon case pack has averaged
over $7,300,000 annually.Of this,the Susitna River system is
estimated to produce annually 38 percent or about $2,774,000.
36.Sport fishing pressure in the Susitna Basin is light,
with the primary limitation being that of access.Many lakes and
rivers afford landing sites for float-equipped aircraft,and fisher-
men using this method of transportation are frequently rewarded
with limit or near-limit catches.The Alaska Railroad,the pri-
mary means of access to the lower basin,parallels the Susitna
River from Nancy at railroad mile 181 to Gold Creek at railroad
mile 263,and crosses many fine fishing streams tributary to the
main river.During the summer season,trains make unscheduled
stops at these streams to accommodate fishermen.The comple-
tion of the Denali Highway in 1957 opened the upper Susitna Basin
to fishermen.The Tyone River,originating at Lake Louise and
flowing northwest to the Susitna River,is proving increasingly
popular with boat fishermen.
Without the Project -Devil Canyon
37.The areas affected by this proposed project feature are
best discussed when considered as two separate sections;from
the confluence of the Susitna,Talkeetna,and Chulitna Rivers at
river mile 85,upstream to the Devil Canyon damsite at river mile
134,a distance of 49 river miles,and the Devil Canyon impound-
ment area about 29 river miles in length (Fig.5),
13
Figure 5.
DENALI DAMSITE
AND RESER VOIR
(25 miles long)
Schematic Map showing principle
tributaries and distances.
SUSITNA RIVER BASIN
PORTAGE
CREEK
TALKEETNA RIVER
~DEVIL CANYON DAMSITE
.AND RESERVOIR
49 miles (.)V 29 rni les long
CHULITNA \
RIVER .
I-'
H:>-
COOK INLET
38,That section of the Susitna River downstream from Devil
Canyon to its confluence with the Talkeetna and Chulitna Rivers is
fed by a few clear tributary streams which furnish habitat for rain-
bow trout,grayling,lake trout,Dolly Varden char,and burbot,and
spawning and rearing grounds for the five species of Pacific salmon.
Portage Creek,3 miles below the damsite,is the last tributary up-
stream on the Susitna River where significant numbers of spawning
salmon have been noted,It is not known how extensively the main
stem Susitna below the damsite is utilized for spawning,but such
usage is probably light due to the silt-laden water and the relatively
muddy,sandy nature of the channel.Sport fishing between the dam-
site and confluence of the Susitna,Talkeetna,and Chulitna Rivers
is limited to the mouths of a few clear-water tributaries.It is pre-
sumable that no significant changes in either fish spawning or sport
fishing will occur without the project.
39.The Devil Canyon impoundment area is a rugged,narrow
canyon with several rapids and a few clear-water tributaries,the
largest being Fog Creek and Devil Creek.Grayling,whitefish,
burbot ,suckers,and cottids occur in these tributaries and in the
main river.Due to a paucity of sizeable tributary streams and re-
moteness of the area.sport fishing is practically non-existent.
Little change is anticipated in fish populations or fishing pressures
without proje ct development.
40.Investigations conducted by the Fish and Wildlife Service
intermittently from 1952 to 1958 failed to reveal the presence of
adult or young salmon above the proposed Devil Canyon d arris i.te .
No actual waterfalls or physical barriers have been observed in or
above the Devil Canyon area which would preclude salmon from
utilizing the drainage area above the damsite.However,the most
logical reason for the absence of salmon from the area is the
probability of a hydraulic block resulting from high wate r velocities
for several river miles within Devil Canyon (Fig.6).It is doubtful
that the area above Devil Canyon will become accessible to and
utilized by anadromous fish without project development.
Without the Project -Denali
41.In the Denali area,the affected sections are considered
in two parts;the area from the head of the Devil Canyon Reservoir
to the Denali damsite at river mile 248,for a distance of 85 main
stem miles,and the Denali impoundment area,which is about 25
miles long.
15
Figure 6.
Fhoto by Dick Hensel
Possible hydraulic barrier to ascending salmon several
miles above Devil Canyon Damsite.Note slide lower
right.
42.From the Devil Canyon Reservoir upstream to the Denali
impoundment,several tributaries enter the Susitna River.The larg-
est of these are the Maclaren River,which is glacially turbid,and
the Oshetna and Tyone Rivers which are clear.Smaller streams in-
clude Deadman,Wa.tana ,Kosina,jay,Goose,Coal,and Clearwater
Creeks.In this section of the Susitna,only burbot have been cap-
tured during the summer.Clear tributary s t r e arn s contain grayling,
whitefish,burbot,suckers,and cottids.Lake trout are present in
certain of the tributary drainages which contain deep lakes.Fishing
pressure on the mainstem Susitna is negligible and limited to the
mouths of some of the clear-water tributaries.It is expected that
this pressure will show only a slight increase without the project.
43.In the Denali i rrrpo und me nt area,the major tributaries to
the Susitna River are Raft,Butte,Windy,and Valdez Creeks which
are clear and Boulder Creek which is turbid.The clear streams
contain grayling,whitefish,burbot,suckers,and cottids.Lake
trout are found in some of the small lakes adjacent to the river.
Anadromous fish are not pres ent.Stream fishing,principally for
16
grayling,is not extensive and is generally confined to the mouths of
clear tributaries.Sand Lake.easily accessible from the Denali
Highway,is fished for lake trout.Opening of the Denali Highway
has provided access to this area and establishment of tourist facili-
ties and trails portends increasing fishing pressure.
With the Project -Devil Canyon
44.In that area from the confluence of the Susitna,Chulitna,
and Talkeetna Rivers to the damsite at Devil Canyon,it is doubtful
that any significant changes to the sport fishe ry will occur.However.
the Susitna River in this area serves as the migration route for salm-
on ascending to the spawning tributaries.Releases of water,either
colder or warmer than normal stream temperatures,could affect
the attraction of salmon to such tributaries.Possible flushing and
scouring action that would occur as a result of sudden changes in
discharge from the Devil Canyon Reservoir may alter production of
insects and other fish food.
45.From available records of water contribution of the
Susitna,Chulitna,and Talkeetna Rivers.it appears that the project
will have no effects to the anadromous fish runs or sport fish below
this confluence to the ri ve r I s mouth at Cook Inlet.
46.In the reservoir to be formed by the Devil Canyon Darn,
it is doubtful that any significant effects will be sustained by the
fishery resources.Inundation of the lower portions of clear-water
tributaries may have a limited detrimentf.tl effect on some species.
However,this may be offset by elimination of falls near the mouths
of some of these streams which will be flooded,thereby permitting
increased fish movement and utilization.Although the reservoir
will improve access,fluctuating water levels and turbid waters will
limit both fish production and fishing pres sure.
With the Project -Denali
47.In the area from the Devil Canyon impoundment up-
stream to the Denali damsite little change in the overall fishery is
anticipated,even though water will not be released from the Denali
Reservoir from April through September.This will result in
virtual dewatering of the 11 miles of the Susitna River between the
dam and the mouth of the Maclaren River.This section currently
contributes little to game fish production.Under project develop-
ment,it may serve as a wintering area for fish.Reduced flows
will have less effect on fish movement and food production below
the mouth of the Maclaren River,and these effects will become
progressively less severe downstream as each tributary adds more
water.
48.Fall and winter flows in this section of the Susitna River
may consist of turbid glacial water stored in Denali Reservoir,in
contrast to the normal clear water at this time of year.This pos-
sible change from clear to turbid water could affect the wintering
habitat with attendant effects to the fish species utilizing the river.
Should releases from the Denali Reservoir be relatively clear,winter
fish habitat may improve since flows will be substantially increased.
Improvement is particularly likely if these releases are controlled
to minimize fluctuations.
49.The Denali Reservoir will inundate 25 miles of the
Susitna River,several small lakes,and 13 miles of the lower por-
tions of several clear -water streams which presently support an
expanding sport fishery.However,the middle stretches of these
streams will become accessible due to the availability of the reser-
voir for boat travel and float-plane landing.The Bureau of Recla-
mation estimates that only about 14 percent of the inflow will be
glacial,with the remaining percentage being snow-melt runoff and
spring -fed waters.Retention of water in the reservoir throughout
the summer months will permit some warming to occur.The degree
of turbidity to be expected from the glacial inflow is not known;
however,observations elsewhere indicate that glacial silt tends to
remain in suspension rather than settle out.Further observations
generally indicate that turbid lakes are not only less productive of
fish life than clear lakes,but less attractive to sportsmen.There-
fore,the degree of turbidity will partially determine the fishe ry
productivity and utilization of the impoundment area.Fluctuating
water levels will further limit fish life by restricting food produc-
tion in the shoal areas of the reservoir.
18
WILDLIFE
Without the Project -Devil Canyon
50.The dominant vegetative cover throughout the Devil
Canyon impoundment area is spruce.Low bottomland along the
main river and the tributaries supports black spruce-aspen stands.
White spruce occurs on the steep side hills in conjunction with
paper birch,dwarf birch,black spruce,and occasional stands of
aspen and cottonwood.Dwarf birch is present in the rolling country
on each side of the canyon,while willow occurs infrequently through-
out the entire area.The understory includes blueberry,low-bush
cranberry,narrow-leaved Labrador tea;crowberry,fireweed,
mosses,and lichens.
51.Game populations are limited in number along the steep
canyon walls which comprise most of the area to be flooded.A
few moose and black and grizzly bear are present.Segments of
the Nelchina caribou herd periodically range throughout the impound-
ment area.However,at no time of the year are caribou resident to
the area nor is the area located on any re cently-utilized migration
route.
52.A limited number of spruce grouse inhabit the area.
Ptarmigan would probably be present during peak population periods,
53.Beaver,present in sloughs along the river,are probably
the most abundant fur bearers.Other spe des of fur animals present
in sparse numbers include land otter,mink and fox.Wolves occa-
sionally travel through the area.Other bur bearers that may be
present are lynx,marten,wolverine and muskrat.
54.Waterfowl use of the area is limited to a few mergansers
which nest in tributaries to the Susitna River.
55.Hunting and trapping in the impoundment area are virtu-
ally non-existent due to inaccessibility and low populations of wild-
life.This condition can be expected to remain without project
development.Even with road building and settlement of the region,
game species would probably not be sought in the impoundment area
due to low numbers and difficulties associated with hunting the steep
canyon walls and traveling on the relatively turbulent Susitna River.
19
Without the Project -Denali
56.The upper section of the Denali impoundment includes
extensive river bottomland containing abundant sedge and willow
vegetation.Below the mouth of Valdez Creek,the area narrows
with sedge and willow in the river bottom,and spruce,dwarf birch,
and a heath plant formation composed of blueberry,low-bush cran-
berry,Labrador tea,and crowberry on the side hills.The im-
poundment area spreads out below the mouth of Butte Creek and
contains lakes,potholes,and marshes,separated by higher well-
drained land.Spruce and dwarf birch occur throughout with heath
plants and lichens as an understory on the better drained sections,
and sedge and willow along water bodies.
57.The Denali impoundment area supports a moose popu-
lation of slightly less than one moose per square mile throughout
all seasons of the year.Without the project,and based on moose
productivity studies els ewhe r'e in Alaska,the moose population will
probably increase for the next several years and then stabilize at a
higher density level.
58.The Denali impoundment area is located within the
range of the Nelchina caribou herd,estimated to number over
50,000 animals.Scattered bands and stragglers may occur any-
where throughout the range,including the impoundment area,at
any time of the year.However,the principal calving .and summer-
ing grounds lie outside the impoundment area to the south.Histor-
ically,wintering grounds for the main segment of the Nelchinaherd
have been the Lake Louise Flats.An unexplained,westward shift
in winter range use has been evident in recent years.As many as
20,000 caribou have been observed in Monahan Flats for limited
periods.This is an area of about 400 square miles which com-
prises about 2 percent of the total Nelchina caribou range.That
section of the impoundment area north of Valdez Creek includes
the eastern one-eighth of Monahan Flats.Intermittent caribou
utilization of the Monahan Flats,which includes the northern sec-
tion of the impoundment area,will probably continue without project
development.Sedge and Li che n s ,which are highly important winter
food plants for caribou,are generally in better condition in this
locale than in areas utilized by wintering caribou in past years.
Therefore,Monahan Flats is a desirable wintering area.The re-
mainder of the impoundment area is utilized less by caribou than
this northern section.
20
59.The southern half of the impoundment area is in one of
the most popular big game hunting regions in the State ,due to its
accessibility from the recently completed Denali Highway and the
availability of moose and caribou close to the road.The northern
half of the Denali impoundment is part of the Denali Reserve,an
area now closed to hunting.This reserve extends east and west
for 80 miles and is situated on the north side of the Denali Highway.
Several moose are harvested each year from within and adjacent to
the open section of the project area.Without project development,
hunting pressure for moose in the open areas will increase.Should
recurrent suggestions to open the Denali Reserve and/or an either-
sex moose season be adopted by the Alaska Department of Fish and
Game ,additional increases in the moose harvest will follow.
60.That se ction of the project area lying south of the Denali
Highway is part of a region which receives rather intensive hunting
for caribou during the first part of the season .The harvest ,which
varies from year to year depending on the distribution and move-
ment of the caribou,would probably not be increased either by fur-
ther liberalization of the present limit (3 caribou)or extension of
the season.Hunting pressure,however,is expected to increase
without project development.Should the Denali Reserve be opened
to big game hunting,hunting pressure for caribou could be exp ected
in the northern half of the impoundment area.
61.The area supports both black and grizzly bear;their
harvest is mainly incidental to other big game hunting.
62 .Spruce grouse,ptarmigan,and snowshoe hare,whose
numbers fluctuate periodically,are present throughout the area but
have not been abundant in recent years.Hunting for these species
has been light and generally incidental to big game hunting.Hunting
pressure may be expected to increase somewhat with an increase
in human population ,but harvest will still be large ly dependent upon
bird numbers.
63 .Wolves,red fox,wolverine,beaver,muskrat,and land
otter are present in the area.Other fur bearers possibly present
include mink ,marten and coyote.The present annual fur harvest
probably does not e xceed 20 beaver taken by one or two year-round
residents near the Denali Highway crossing of the Susitna River.
The potential fur yield is far greater than this and ,with increased
settlement,trapping would probably increase substantially.
2.1
64.The impoundment area furnishes nesting and rearing
habitat for waterfowl.Species nesting in the area include the
trumpeter and whistling swan;Canada goose,scaup,baldpate,
green-winged teal,mallard,pintail,bufflehead,goldeneye,old
squaw,harlequin,shoveller,canvasback,white-winged scoter,
and American merganser.Migrant waterfowl use the area for
feeding and resting during both spring and fall flights.
65.Waterfowl hunting at present is negligible.Without
project development,the area would continue to furnish ne sting,
rearing,and resting habitat.Hunting pressure may increase with
an increase in human population.
With the Project -Devil Canyon
66.Limited amounts of moose,caribou,bear,spruce
grouse,and fur animal habitat will be inundated and destroyed.
Fluctuating water levels and the precipitous topography of the
area will preclude creation of new game habitat.Access to the
area will be improved by a road from the Alaska Railroad section
at Gold Creek to the damsite and by creation of the 29-mile long
reservoir,which will furnish a surface for boat and plane opera-
tion.This improved access will undoubtedly attract some hunters
and,perhaps,trappers,and result in an increased yield of the
presently lightly harvested game of the surrounding area.
With the Project -Denali
67.About 61,000 acres of land will be inundated.Most of
this is moose habitat,the use of which varies according to the
season.Since it is unlikely that the surrounding area can support
the displaced animals,the moose population of the impoundment
area will be lost.With project development,a new road will be
constructed around the lower half of the reservoir.This road,as
well as the lake itself,which will afford boat and plane operation,
will add to the accessibility and harvest of moose from the range
surrounding the project area.
68.About 33,000 acres of good caribou winter range,which
receives intermittent winter use by the Nelchina caribou herd,
will be destroyed by inundation.An additional 28,000 acres of
less valuable range,which receives intermittent use throughout
the year,will also be inundated.Although substantial numbers of
22
caribou occasionally use this overall area.the range that will be
destroyed is apparently not of major importance when compared
with other segments of the Nelchina range.No main caribou.travel
routes will be inundated.Improved accessibility as a result of
project development will probably increase the caribou harvest in
the surrounding area.
69.Spruce grouse.ptarmigan and snowshoe hare habitat
will be inundated and lost by project development.
70.A minor hazard to game animals may be created if a
series of ice shelves is formed around the perimeter of the reser-
voir as water is drawn down during the winter.
71.Inundation will destroy fur bearer habitat and areas used
by waterfowl for nesting and rearing.A fluctuating waterline will
preclude creation of alternate habitat around the reservoir shore-
line to replace these los s e s ,The impoundment will furnish in-
creased resting areas for waterfowl,particularly during the fall•migra tion.With a lake for boat and float-plane operations.the
area will probably become increasingly important for waterfowl
hunting as the population of Alaska increases.
23
DISCUSSION
72.The Devil Canyon Project,if constructed,will result in
relatively insignificant losses to the fishery resources of the Su,-
sitna River Basin.
73.Reservoirs fo r med as a result of the Devil Canyon and
Denali Dams will inundate about 54 miles of the main stem Susitna
River,a minimum of 15 miles of clear-water tributaries,and some
lake habitat.Fluctuating water levels in both reservoirs win limit
maximum development of impoundments for fish habitat.A further
restriction to optimum fishery habitat development will be the
turbid waters caused by glacial silt runoff.The degree of this
turbidity cannot be predicted on the basis of available data;how-
ever,fishery production will decrease in proportion to turbidity.
Although access will be improved by project development,only
limited increases in sport fishing are anticipated where the clear-
water tributaries enter the impoundments.It is anticipated that
the paucity of clear streams,the fluctuating water levels,and the
presence of better fishing in adjacent areas will preclude high
usage of the impoundments by anglers.
74.If water released from Devil Canyon Dam for power gen-
eration is different in temperature from that of the natural river,
the attraction and migration of salmon and other fish to the tribu-
taries between the confluence of the Su s i.tria ,Chulitna,and
Talkeetna Rivers and the dam may be altered.Limited spawning
and other fish usage of this area would be reduced by the introduc-
tion of cooler water,while warmer waters would result in
increased fish food production and fish utilization in this area.For
these reasons,water releases should be made,if feasible,from
a reservoir level that corresponds as nearly as possible to normal
or warmer than normal .river temperatures.
75.The releases indicated in the Bureau of Reclamation
Operating Plan for the Devil Canyon Dam will be adequate to sus-
tain fish habitat in the Susitna River downstream from the project.
However,during dam construction,reservoir filling,and through-
out the life of the project,flows of not less than 2,000 c.f.s ,
should be maintained.If the initial reservoir filling occurs during
the period October through April,inclusive,the minimum flow
requirement would be 1,000 c.f.s ..Sudden changes in water dis-
charge should be avoided to prevent scouring of the channeL
24
76. Stream ecology and fish life will be modified in the 85
miles of the Susitna River between the Devil Canyon Reservoir and
the Denali Dam. The plan of operation calls for water above
Denali Dam to be impounded during the spring and summer and to
be released during the fall and winter. Changes will be most pro
found in the 11 miles of the Susitna River from the Denali Darn to
the Maclaren River. However. during the summer months when
such flows will be stored, this section of stream apparently re
ceives little usage by fish; therefore. this summer dewatering may
be of little consequence. Below the Maclaren River, it is most
likely that summer fish usage increases. Water records indicate
that incremental flows from the various tributaries in this section
are normally greater than the flow of the Susitna River at Denali
Dam. Even without flow in the Susitna River from Denali Reser
voir. the amount of water from the tributaries is believed adequate
to sustain fish habitat and fish life.
77. During the fall and winter months. flows between Denali
Darn and Devil Canyon Reservoir will exceed normal flows without
the project. Such increases will probably be of benefit to wintering
fish populations in the Susitna River. particularly if the flow from
Denali Darn is relatively clear. However. if this water is glacially
turbid, it may be of less value than the normally clear water which
currently occurs.
78. Although minimum year-round releases from the Denali
Dam would probably reduce the changes in the stream habitat, such
alteration of habitat without minimum flows will not be particularly
adverse .to the fishery resources. Therefore, minimum flows are
not required during spring and summer months when the project is
in operation. In order that fish habitat may be preserved durlng
the construction and initial filling period and project operation.
flows of not less than 150 c. f. s. should be maintained from October
through March. When the project is fully operational, flows released
from the dam for power generation downstream at Denali will be
adequate to maintain the winter fish habitat.
79. Although there have been two reports of fish above the
Devil Canyon Dam that could have been salmon, no verified report
exists of salmon above this site. A strong probability exists that
a hydraulic block (comprised of swift water for several miles) pre
vents the movement of anadromous fish to the Susi tna River drain
age above the Devil Canyon damsite. It may be that, with some
25
._--_ .._-_.----------_..__ ._---_.---------------
special water condition which might exist periodically,an occa-
sional salmon is able to traverse the area.There are no indica-
tions,however,that any significant numbers of salmon or other
anadromous fish will be blocked by construction of the Devil
Canyon Dam;therefore,no fish ladder or other fish facility is
recommended for inclusion in the plans for the Devil Canyon Dam
at this time,
80.Above the Devil Canyon d arn s i te ,there are many ql ea r «
water tributaries and lake systems that may be utilized by salmon
for spawning and rearing purposes.Elimination of the hydraulic
block by inundation togethe r with some type of fish-handling
device might make it possible to bring the middle and upper Su-
sitna drainage area into salmon and steelhead trout production.
Detailed studies will be conducted to determine the feasibility and
opportunities for enhancement features to utilize these potential
spawning areas.
81.Limited amounts of wildlife habitat will be destroyed by
inundation with attendant losses to the wildlife species dependent
on these habitats.Because of generally low populations and poor
accessibility,these losses are considered to be of a minor nature.
The topography of the reservoir perimeters as well as the season,
duration,and severity of fluctuating water levels in the two reser-
voirs make mitigation of such limited losses by development of
replacement habitat improbable,It is possible that,as a result
of project construction and operation,access to currently remote
areas will improve with increased utilization of,the game and fur
species by hunters and trappers.
26
C.L.ANDERSON,COMMISSIONER
l.fay 6, 1960
STATE OF ALASKA
DEPARTMENT OF"F"ISH AND GAME
BOARO OF FISH AND GAME
RICHARD .JANSON,.JR.,CORDOVA
CHAI RMAN
ARNOLO BROWER,POINT BARROW
OSCAR DYSON,KODIAK
ARTHUR M.HAYR,F'A1RBANKS
R08ERT I.MARTIN,NAKNEK
ROY S.SELFRIDGE,KETCHIKAN
ERLING STRAND,PETERSBURG
229 ALASKA OFFICE BUILDING .JUNEAU,ALASKA
STATE OF ALASKA
WILLIAM A.EGAN
ClDVERNDR
Mr.John T.Gharrett,Regional Director
Bureau of Commercial Fisheries
and
Mr.Urban C.Nelson,Regional Director
Bureau of Sport Fisheries and Wildlife
U.S.Fish and Wildlife Service
Box 2481,Juneau,Alaska
Gentlemen:
The Department has reviewed the report of the U.S.Fish
and Wildlife Service dated }~4,1960 concerning the Bureau of Reclama-
tion's planned.Devil Canyon Project on the Susitna River Basin.We agree
with your findings as to the effect of the project on fish and game,and
concur in the recommendations for the protection of these resources as
outlined in this report.
Sincerely,
AlASKA.DEPARTMENT OF FISH &GANE
(j)a.U»v 1f~
1.fal ter Kiz-kneas.,
Acting Commissioner
WK:kp