HomeMy WebLinkAboutAPA3061.-
:.J RECbIVED
JAN231986
ALASlCA DEF..Of fj.:>H &GA,Mf
Sua",'River IMtreamFlo\l(
ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
Federal Energy Regulatory Commission
Project No.7114
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HA~ZA-EIASC'SUSITNA J'INT VENTU~E
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Alaska Resources
Library &Informanon SefVlQe$
Anchorage,Alaska
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I.INTRODUCTION III •••••••••••••
~-
....,
-
II.
TABLE OF CONTENTS
Project Setting and Description ••••••••••••••••••.•••••••••••••••
Project Influence on Salient Physical Processes •••••••.•.••••••••
Flow ' .
Total Suspended Solids .
Turbi di ty -.
Temperatu re .
Fish Resources in the Middle Susitna River •••••••••.•••..••••••••
Scope of the IFR Studies •••••.••••••••••••••••••••••••••.I11 ••••••~
RESPONSE~JUVENILE CHINOOK HABITAT TO MAINSTEM DISCHARGE •••••••
Chinook Salmon Biology in the Middle Susitna River ••••••••••••••.
Distribution and Abundance •.•.••••••••••••••.•.••••..•••.•••
Growth of J uven il e Ch i nook ••.••.••.••.••••••••••.•••••••••••
Modeling of Juvenile Chinook Habitat ••••.•••••••••••••.••••••••••
Su i tab i 1i ty Cri te ri a .....e •••••III •••0 ~•••••Cl ••••••••••••G ••••
Velocity ~0 ••••••••••••••G •••
Wa ter Depth 0 •••••••••••••••••
Cover ..•...."'~*••••••••••III ••••••••••••III •••ell ••••III ••••III ••
Ii
Extrapolation of Modeled to Non-Modeled Sites ••••••••••..•••
Non-Modeled Habitat Factors .
Temperature .
Food Ava i 1ab;1i ty.,~III ••••••••••••••••••••
Pre dat ion ~-..~~~.
Space Requirements e •••••
Overwintering Survival e •••••••••••••••••••••••••••••
WUA Response Curves for Representative Groups I-IX .••••.•.•••••••
Interpretation of Response Curves ••••••••••••••••••••••••••••••••
Correlation with Juvenile Chinook Distribution Data .••••••••
Aggregation of Curves for System-Wide Response ••.•••••••••••
Fall Transition Modifications •••••..•••••••••••••••••••••..•
Applicability of Existing WUA ~~qp~for
Overwintering Assessme~~JL~•••••••••••••••••••••
Alaska Resources
Lih,.a~'v <tfonnatlon ServIces
~\nchorage.Alaska
Page
1-1
1-1
1-4
1-5
1-5
1-7
1-10
1-12
1-14
II-I -/--
II-I
II-I
11-5
11-5
11-10
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11-10
11-13
11-13
11-20
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11-22
11-24
11-24
11-25
11-27
11-30
11-31
11-41
11-44
11-44
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,-
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III.
IV.
Application of WUA Curves .•.......••.•..••.•.•G.c.o ••••••••••••••
CHUM SALMON ••••••••••••••••••••••••••••II _e ••II •II 0 ••G'•e _••II _0 •••••
OTHER SPECIES •••••
Introduction .•..••
Sockeye Salmon ••••
Adul ts .
Habitat Utilization •••••
Habitat Requirements ••
Habitat Availability •.
II-46
III-l
IV-l
IV-l
IV-2
IV-2
IV-4
IV-6
IV-lO
Pink Salmon ••
Habitat Utilization.
Habitat Requirements •••
Habitat Availability ••••~•••••••••••••••
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-
-
-
Juven·iles ....•.••••.•••.••.
Habitat Utilization ••
Habitat Requirements ••
Habitat Availability ••
Coho Salmon •••••
Adults .....a.a •••••••••••••
Habitat Utilization ••
Habitat Requirements.
Habitat Availability ••
Juveniles .
Adul ts .
Habitat Utilization ••
Habitat Requirements ••••
Habitat Availability.
Juveniles •••••••.•.•.•.•.•.
Habitat Utilization •••
Habitat Requirements ••
Habitat Availability ••
Rainbow Trout.
....................-.
..
IV-l3
IV-13
IV-l5
IV-l8
IV-20
IV-20
IV-20
IV-22
IV-22
IV-25
IV-25
IV-28
IV-3l
IV-33
IV-33
IV-33
IV-34
IV-34
IV-34
IV-39
IV-39
IV-39
IV-40
-
Adu 1ts •••••••••••••••••••••••
Habitat Utilization •••••
Habitat Requirements •••••••.
Habitat Availability •.•.•...
ii
IV-40
IV-40
IV-44
IV-47
'~~~~----------------,
Arctic Grayling ••
-Juveniles ..••.••.•••••••••
Habitat Utilization ••
Habitat Requirements.
Habitat Availability.
................................................
IV-47
IV-47
IV-48
IV-48
IV-49
Adul ts e-•••••
Habitat Utilization •••
Habitat Requirements ••••
Habitat Availability ••
.....................................
IV-49
IV-49
IV-50
IV-50
Burbot •••••••
-
-
-
Juveniles •....•.................
Habitat Utilization ••••••••
Habitat Requirements ••••••••••••••
Habitat Availability •••••••••••••••••
....................................................
Adul ts .
Habitat Utilization •••
Habitat Requirements.
Habitat Availability.
Juveniles .••.•••...•.o •••••••
Habitat Utilization •••.•
Habitat Requirements ••
Habitat Availability .
IV-52
IV-52
IV-52
IV-53
IV-54
IV-54
IV-54
IV-54
IV-55
IV-55
IV-55
IV-55
IV-55
Dolly Varden •••••ill •••••••••••••••••••••••••••••••••••••••••••••IV-56
-
V.
VI.
Adults ••
Habitat Utilization ••••
Habitat Requirements ••
Habitat Availability.
Juveniles .
Habitat-Util ization ••
Habitat Requirements.
Habitat Availability •••••
SUMMARY •••••••••••0 •••••••••••••••••••••••••ill ••••••••••••••••••••
LITERATURE CITED ••••••••••••••••••••.••••••••••.e-••••••••••••••••
iii
IV-56
IV-56
IV-56
IV-57
IV-57
IV-57
IV-57
IV-58
V-I
VI-l
Extent and time of ice cover on the middle
Susitna River under natural and with-
project conditions -......................1-13
-
-.
-
-
-
Figure I-I.
Figure 1-2.
Figure 1-3.
Figure 1-4.
Figure 1-5.
Figur-e 1-6.
LIST OF FIGURES
Susitna River drainage basin and fish
species by study zone (from University of
A1ask a 1985)e-•••••
Estimated wi th-proj ect mean monthly flows
at Gold Creek compared to natural flows
(data from APA 1985)•••••••••••••.••.••.••••••••...•.
Estimated with project mean monthly sus-
pended sediment concentr,ati ons in the
middle Susitna River compared with natural
values (from Harza-Ebasco Susitna Joint
Venture 1985)..................................•.....
Estimated with-project mean monthly tur-
bidity val ues at Gold Creek compared to
natural values (with-project values from
APA 1985,natural values from ADF&G 1983g)..•.••.....
Est'imated with-project temperatures at two
river miles (RM)at three stages of develop-
ment compared with natural temperatures
(modified from APA 1985)..•••..•..••..•..•.•.•••••••.
1-2
1-6
1-8
1-9
1-11
......
-
Fi gure II-1.
Fi gure II-2.
Density distribution of juvenile chinook
salmon by macrohabitat type on the Susitna
River between Chulitna River confluence and
Devil Canyon,May through November 1983 •
Percentages are based on mean catch per
cell (from Dugan,Sterritt and Stratton
1984)-.---.----..----.--._.-I-I -4 -
Chinook salmon (age 0+)mean length and
range of lengths by sampl ing period for
fish collected in the lower and middle
reach of the Susitna River,1984 (from Roth
and Stratton 1985)...................................11-6
Figuy'e II-3.Linear regression of the weight/length
relationship for juvenile chinook salmon
collected at the Talkeetna stationary
outmigrant traps,1984 (from Roth and
Stratton 1983).•.....................................
iv
II-9
-
-
-
Fi gure II -4.
Figure II-5.
Figure II-6.
Figure II-7.
Figure II-8.
Figure II-9.
Figure II-lO.
FigureII-ll.
Figure II-12.
Fi gure 11-13.
Fi gure II-14.
Figure II-15.
Figure IV-I.
Velocity suitability criteria used to model
juvenile chinook habitat (WUA)under clear
and turbid water conditions in the middle
Susitna River (from Steward 1985)....................11-11
Depth suitability criteria used to model
juvenile chinook habitat (WUA)under clear
and turbid water conditions in the middle
Susitna River (from Steward 1985)....................11-12
Cover suitability criteria used to model
juvenile chinook habitat (WUA)in the
middle Susitna River.Separate criteria
are presented for cl ear and turbid water
conditions (from Steward 1985).......................11-15
Aggregate response of WUA for juvenile
chinook to mainstem discharge for Repre-
sentative Groups I-IX (from Steward et al.
1985)•.•.•..e .•••••.••••••••••e ••••••••-••••••••eo.....11-18
Factors that potentially influence rearing
juvenile chinook ....•.......•....•.•.•..•.•..•.•.•.e.11-21
Sampling design for PHABISM modeling sites
(from Steward et al.1985)...........................11-28
WUA responses of Representative Groups I -
IX for RM 98.5 to 114.0..............................II-29
WUA responses of Representative Groups I -
IX for RM 114.0 to 131.0.............................11-38
WUA responses of Representative Groups I -
IX for RM 131.0 to 147.0.............................11-39
Aggregate WUA response curve of Representa-
tive Groups I -IX for the middle Susitna
River e......11-40
Conceptual flow diagram of incorporation of
temperatures into the model..........................11-45
Comparison of habitat factors by time
period under natural and with-project stage
II conditions ....•.•.•........eo......................11-47
Comparison of revised passage criteria
thresholds for successful and unsuccessful
passage of chum sa 1mon with Criteri a
Curve I..............................................IV-7
v
-Figure IV-2.Depth and velocity habitat requirements for
spawning sockeye in the middle Susitna
River e •••••••·.ec •••••IV-B
Fi gurle IV-3.
-Fi gurle IV-4.
Figure IV-S.
Figure IV-6..-
Figurl~IV-7.
Figure IV-B.
.-
F'i gure IV-9.
Figure IV-lO.
Figure IV-H.
-F'igure IV-12.
F'igurE~IV-13.
F'igure IV-14.
F'igure IV-IS.
F"igure IV-16.
,.....
Substrate util ization by spawning sockeye
salmon .in the middle Susitna River •.•••.••••••••••••.
Comparison of habitat requirements for
sockeye and chum salmon ••••••••••••••••••.••••••..•••
Habitat utilization by juvenile sockeye
salmon ...........................................••..
Depth and velocity habitat requ i rements for
juvenile sockeye in the Susitna River ••••••••••.•••..
Cover suitabilities for juvenile sockeye
salmon in the Susitna River ••••••••.••••••...•••••.••
Habitat availability for juvenile sockeye
salmon based on surface area response of
important habitat types •••.••.•.•••••..•••••.••••••.•
Depth and velocity habitat requirements for
spawning coho salmon in the middle Susitna
River C1 ••oU
Substrate uti 1ization by spawning coho
salmon in the middle Susitna River •••••••••.•.•••••••
Habitat availability for spawning coho
salmon based on area response of important
habitat types e _••••ill _•••••••••••••
Habitat utilization by juvenile sockeye
salmon in the middle Susitna River •••.••..•••.••••••.
Depth and velocity requirements for juve-
nile sockeye salmon in the Susitna River •••••••••.•.•
Cover suitabi 1i ties for juvenil e sockeye
salmon in the Susitna River .•..•••••••..••••••••••••.
Habitat availability for juvenile coho
sa lmon based on surface area response of
important habitat types •••••.••.•••••..•.•••...••••.•
Depth and velocity habitat requirements for
spawning coho in the middle Susitna River •••••••...••
vi
IV-9
IV-ll
IV-14
IV-I6
IV-I7
IV-19
IV-23
IV-24
IV-26
IV-27
IV-29
IV-3D
IV-32
IV-36
""'",
-
-
-
-
,.-
-
-
Figure IV-I?
Figure IV-lB.
Fi gu re IV-19.
Figurle IV-20.
Figure IV-21.
Figure IV-22.
Figure IV-23.
Substrate utilization by spawning pink
salmon in the middle Susitna River •••..•..•••••••••••
Habitat availability for spawning pink
salmon based on area response of important
habitat types .
Boat electrofishing catch of rainbow trout,
Arctic grayling,and burbot in major
habitat types in the middle Susitna River,
1983 e_•••••••••••••••••••••
Frequency distribution of radio-tagged
rainbow trout locations in the Susitna
River during 1984 .•..•.•.•.•.•.••.....••...•....•....
Depth,velocity,and cover habitat require-
ments for rainbow trout captured by electro-
fishing in the middle Susitna River ••••••••••••••••••
Depth,velocity,and cover habitat require-
ments for rainbow trout captured by hook
and line in the middle Susitna River •••••••••••••••••
Depth,velocity,and cover habitat require-
ments for Arctic grayling captured by
electrofishing in the middle Susitna River •••••••••••
vii
IV-3?
IV-39
IV-4l
IV-42
IV-45
IV-46
IV-51
,,_li'iRP',__o,o ,,_
-
-
-
Table II-I.
Table II-2.
Tab 1e II -4 .
T,able II-5.
LIST DF TABLES
Chinook salmon fry population estimates by
site for sloughs and side channels surveyed
in the Susitna River above the Chul itna
River confluence,1984 (from Roth &
Stratton 1985).
Number of fi sh,mean 1ength and range of
lengths for age 0+chinook salmon by
sampling periods on the Susitna River
between Talkeetna and Devil Canyon 1984
(from Roth and Stratton 1985)••••••••••••••••••••••••
Number of fi sh,mean 1ength and range of
lengths for age 0+chinook salmon by
sampling period for the lower Susitna
River,Deshka River and Talkeetna River,
1984 (from Roth and Stratton 1985)••••••.•••.••••••.•
Cover suitabil ity criteria recommended for
use in modeling juvenile chinook habitat
under clear and turbid water conditions
(from Suchanek et al.1984,Steward 1985)••.•••••••••
Primary hydrologic,hydraulic and morpho-
logic characteristics of representative
groups identified for the middle Susitna
II-3
II-7
II-8
II-14
-
T.ab 1e II -6 •
T,able II-7.
Tiab 1elI -8.
Table II-9.
Table II-1D.
Derivation of relative abundance factors
from CPUE and numbers per specific area
informati on .
Relative Abundance Factors for specific
areas in Groups I and II for June to
October Co.
Relative Abundance Factors for specific
areas in Groups III and IV for June to
October e •••••••••••eo ••
Comparison of Relative Abundance Factors
and WUA forecasts for Groups I,II,III and
IV for June to October •••••••.•••.••••••••••••.~••••.
Comparison of Relative Abundance Factors
and WUA forecasts for Groups I,II,III and
IV combined during August and September for
different sections of the river •••••...•••.•..••••••.
viii
11-33
II-34
II-35
11-36
11-43
-
-
-
--
-
F
!
.....
-
-
Table IV-I.
Table IV-2.
Table IV-3.
Table IV-4.
Table IV-5.
(will be provided later)
Average salmon escapements in the middle
Susitna River,by species and location •••••••••.••.•••
Second-run sockeye salmon total slough
escapement in the middle Susitna River,
1981-1984 II •••e
Coho salmon peak index counts in the middle
Susitna River,1981-1984 •••.•••.••••••••••.••••.••••.
Pink salmon peak index counts in the middle
Susitna River,1981-1984 •••••••••••••••••••••••.•••••
ix
IV-3
IV-5
IV-21
IV-35
-
-
I.INT~'.UCTI'N
This document comprises Volume II of the Instream Flow Relationships Report
(IFRR), a two-volume series on instream flow processes in the middle Susitna
River'.The report is the result of work funded by the Aliski Power Authority
as part of its informational needs for the proposed Susitna Hydroelectric
ProjE~ct.The objectives of the IFRR are twofold:1)to identify the relative
importances of salient physical processes to fish resources,and 2)to evalu-
ate and,where possible,quantify the influences of incremental changes in
'impoll'tant physical variables on fish habitat.Volume I addressed the first
objective.It also introduced concepts which are the basis for the more
lrefined analytical techniques described here in Volume II.Volume II presents
the basic framework of an analytical methodology designed to describe the
magnitudes of change in fish habitat associated with alterations in instream
flow processes.
This volume is presented in five sections.The remainder of the introduction
briefly descr"ibes the project and its setting,the project1s influence on
salil::mt physical processes,fish resources in the middle Susitna River,and
the scope of the IFRR studies.This is followed by a three-part analysis of
the influence of important physical parameters on fish resources.Section II
quantitatively describes the response of juvenile chinook salmon habitat to
mainstem discharge using velocity,depth,and cover criteria.Other variables
l,01hi ch may infl uence fi sh habitat,but whi ch were not model ed quantitatively,
.are discussed.The relative importance of each and how they might be incor-
porated into the response curves are discussed.Section III is an analysis of
chum salmon spawning and incubation habitat presented in the same format as
Section II,and Section IV focuses on other fish species in the middle Susitna
!River.Finally,a summary section will present conclusions and discuss the
lapproach needed to ascertai n magnitudes of response for an effective negoti-
,a ted settlement.
Project Setting and Description
The Susitna River is an unregulated glacial river in southcentral Alaska with
a dl"a"inage area of 19,600 square miles (Fig.1-1).It flows 320 miles
1-1
J J 1 1 )J J 1 »J J )J j 1 )}
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N
II SUSiTNA RiVER DRAi"A~E BASiN II ~_I ~A II
P11111ptc1H "'--..(~
lo_......,l2GI Arcllc ...ylItlt.A,"1tO .."'......-.0'-_.0llIII0IlIl
UIo""".CIIu'"••1_.CO/Io ••,.......Do'"v.rd....•....II0II,
ftUlllp!>ICk wtlI..na/\,10k.1_.lDfttnoIo ....k .../lOll"""""'.
,....II'''''''...mbo.t_._-"h.llah•••""lIClulp....·...h,...,,,,....Ih'H.,IA.Illck......k.'Ad ",•••,1 ••
arltklablC'.
"lIMIo ,,""'..Ct"A..lle ,"'clio 1a1lllftY.buot>ol.............a.,,,,...._
..~_.Doll,V._.""_Ie.""n.'1II\,Ioka
IIDUl•....,110..lUCk ...llIAk 10''''''''.....__•_
*.11.11,•••11""••ulplo ....keye ••_••nd Ih,...pl •••".k_'"
'"-"'<1......1I..,.:411 Arcllc ...,.,..Nbol.Doftor VInlttI,_......k ""n.n....'.k.
1_.IDfttnoII .uct..._-"••Ila/\,••""_"'....and
cNll6<*..........
Figure 1-1.Susitna River drainage basin and fish species by study zone
(from University of Alaska 1985).
-I
"'""
-
southwest into Cook Inlet from its headwaters in the Alaska Range.It is
bordered on the north and west by the Alaska Range and on the south and east
by the Talkeetna Mountains.
The river exhibits wide variations in flow in response to changes in weather
patterns and climatic conditions.Seasonal fluctuation is most pronounced
with typical summer flows rang"ing from 16,000 to 30,000 cubic feet per second
(cfs)and winter flows averaging between 1,000 and 2,000 cfs.Climatic
conditions and weather patterns influence flow regimes in the Susitna River
through surface runoff and glacial melt,which are mediated by precipitation
and temperatures.Concomitantly,glacier melt contributes large inputs of
suspended solids to the system.Consequently,high concentration of total
suspended solids (TSS)and turbidities are characteristic of the Susitna at
those times of the year,particularly during the surrmer when glacier melt,
along with snow melt and other surface runoff,is also contributing to high
flows.Thus,·changes in temperature,streamflow,TSS,and turbidity are
correlated.Furthermore,as discussed in Volume I,these are the physical
variables that most influence fish habitat in the Susitna River.
The Susitna Hydroelectric Project,as proposed,will consist of two dams
constructed on the Susitna River to serve energy demands in the Railbelt
r'egion.Construction would occur in three stages:1)Stage I will create an
electrical generating capacity of 440 MW by the construction of Watana Dam,a
700-foot-high rockfill structure.The projected completion date is 1999.
2)Stage II will be completed in 2005 by the construction of a concrete-arch
dam a.t Devil Canyon.Electrical generating capacity at the Devil Canyon site
\Ojlill be 680 MW.3)Stage III would complete construction of the Watana Dam by
r'aising its height to 885 feet with a concomitant increase in electrical
gener'ating capacity to 1110 MW.At the completion of Stage III in 2012,the
total capacity of the project would be 1709 MW.
As originally conceived,the project was to be built in only two stages.The
Alaska Power Authority submitted a license application to the Federal Energy
Regulatory Commission (FERC)in February,1983 to construct and operate the
proje'ct.Subsequent cost-benefit analysis,however,resulted in the formu-
lation of the three-stage proposal as the preferred alternative.
1-3
___,-0 _
-
--
The three-stage project presents no net change in final design and capacity
from that envisioned under the original two-stage plan.However,the modi-
fication in scheduling does require the preparation of an amendment to the
license application.Thus,an amendment will be filed with the FERC in early
1986.A draft of this amendment (APA 1985)has been prepared and is presently
circulating for public comment.Descriptions of all aspects of the project
are available in that document,and the reader is referred to it for
discussions that are most detailed than those presented here.
The major tributaries to the Susitna are the Chulitna,Talkeetna,and Yentna
River's.The Chulitna,a glacial river which originates in the Alaska Range,
joins the Susitna at-river mile (RM)99.The Talkeetna River,which drains
from the Talkeetna Mountains,enters the Susitna at RM 97.The Chulitna and
Talke~etna Rivers,then,join the Susitna at about the same place and,to-
gethe~r,contribute about 59%of the total flow at the Parks Highway Bridge.
For this reason and because of geomorphologic considerations,the confluence
of tlhese three rivers (the three rivers confl uence)serves as a boundary
betw€:en the lower and middle segments of the Susitna River.The lower segment
extends from the confluence to Cook Inlet.The Yentna River enters the lower
segmemt at RM 28.The mi ddl e Sus itna Ri ver extends upstream about 50 mi 1es
from the three rivers confluence to Devil Canyon (RM 150).The upper Susitna
River'exists above Devil Canyon.
Project-related impacts will be dampened in the lower Susitna River because of
the relatively large influences of the Chulitna and Ta"lkeetna rivers,and,
further downstream,the Yentna River.Downstream impacts will be most pro-
nounc:ed in the middle Susitna River and,thus,this segment is the focus of
the majority of environmental assessment work and is the subject of this
l~epor·t.
Project Influence on Salient Physical Processes
As discussed previously,the important riverine physical variables,relative
to the project,are flow,TSS,turbidity and temperature.Each varies under
natural conditions,with predictable trends occurring seasonally.These
natul~al variations will be altered in the middle Susitna River by operation of
the project.The changes which occur wi 11 depend upon the stage of the
1-4
'---'~~~"'!4Ii!!6i!"'.Jjl#.4&4ii...._;;;:h_------
....
-i
""'"i
-
""'"
project and the operational flow regime chosen for that stage.It is impor-
tant to understand the physi ca 1 processes that occur naturally and the poten-
tial changes that are likely toreslJlt from the project before assessments on
fi she~ri es can be made.Therefore,each of the aforementi oned physi cal
varia,bles are described along with anticipated alterations which will result
from project operations.
Flow
Typic:al summer flows "in the middle Susitna River range from 16,000 to 30,000
c:fs \</hile winter flows are much less,ranging from around 1,000 to 3,000 cfs.
In addition to seasonal trends,shorter-term variation occurs in response to
precipitation and temperature.Figure 1-2 shows mean monthly flows at Gold
Creek averaged over the years 1951 to 1983.The peak mean monthly flow
occurred in June at 28,000 cfs,while the minimum flow was slightly higher
than 1,000 cfs in March.Anticipated with-project flows are also shown in
Figure 1-2.The project will dampen the seasonal fluctuations in flow.The
magnitude of seasonal oscillation will be increasingly reduced as development
()f the project proceeds until,by the completion of Stage III,minimum and
maximum flows are about 8,000 cfs and 11,000 cfs,respectively.Mean annual
flows will be about 10,000 cfs.
It millst be understood that the anticipated flows in Figure 1-2 are based on
only one of the flow cases (E-VI)descr"ibed in the application amendment.
This case is the alternative preferred by the applicant because it is thought
to satisfy operational flow requirements while,at the same time,providing an
oppolrtunity to meet fi sheri es objectives.However,adjustments are possi bl e
and may be warranted after the completion of environmental analyses.The
following discussions of TSS,turbidity,and temperature include descriptions
of plredicted differences between natural conditions and the E-VI flow case.
Total Suspended Solids
Tota']suspended solids in the middle Susitna River are generally positively
correlated with flow.That is,concentrations of TSS increase as flow
i ncrleases in response to gl aci er melt and surface runoff.By far the most
1-5
-----------------_._----_....,...,--------...-------------
P"-
i
30
.-10
• •
0----0
..------{I
IJ.••6
...
NATURAL
STAGE I
STAGE II
LATE STAGE
III
-
o
J F M A M J J
MONTH
A 5 o N 0'
-
Figure 1-2.Estimated with-project mean monthly flows at Gold Creek
compared to natural flows (data from APA 1985).
I-6
-
-
-
--
-
,....,
-
--
important contribution to TSS is glacier flour,released during periods of
elevated temperature.Thus,the seasonal pattern of TSS closely follows that
of flow,namely,high in the warmer summer months and low during the winter.
Fi gure 1-3 illustrates the differences between concentrati ons in TSS under
natural conditions and those antic"ipated during the three stages of the
project.Seasonal variations in TSS are expected to decline when the project
becomes operational because the impoundment will release relatively constant
concentrations of TSS throughout the year.However,even though TSS concen-
trations will remain relatively constant at approximately 100-150 mg/l,they
will be higher than natural conditions during the fall and winter,and lower
during the spring and summer.
Turbidity
Turbidity is a measure of the scattering of light in water from suspended
sediment.Thus,TSS and turbi di ty are positively correl ated,although the
exact relationship is situation-specific and difficult to quantify.Part of
the problem in relating turbidity to TSS is because of differences in particle
size.Generally,turbidity is imparted to a body of water by particles less
than three microns in size,whereas TSS can consist of a much wider range of
particle sizes.The larger of these are apt to quickly settle from suspension
in quiescent water.Although these larger particles contribute very little to
turbidity readings while they are in suspension,they do add considerable mass
to concentration values of TSS.Thus,the relationship between turbidity and
TSS can be very different between lotic and lentic systems.Another source of
inaccuracy in establ ishing a relationship between TSS and turbidity is that
significant differences in turbidity readings can exist between samples with
similar concentrations of TSS because of differences in particle geometry.
Never'theless,with-project turbidity estimates were established by applying
a conversion factor to predicted TSS values.Although the use of this
conversion factor is somewhat questionable and more work is probably required
to elucidate a valid relationship between the two variables,the general
seasonal trends in TSS and turbidity should theoretically be similar.Figure
1-4 shows natural turbidity values in the middle Susitna River and predicted
with··project values calculated using a turbidity to TSS conversion ratio of 2
1-7
~.')-1 -}C-'.'1 1 1 1 1 1 1 )}.'}1 ]
!
1260 1
STAOE I
o----o·8TAOE n
STAGE ill110000001
\4 MEAN NATURAL
260
200
160
100
60
0
0 N 0 J F M A M J J A •
600
760
1000
TSS
(mgl J)
.....
I
00
Figure 1-3.Estimated with project mean monthly suspended sediment
concentrations in the middle Susitna River compared with
natural values (from Harza-Ebasco Susitna Joint Venture
1985).
lit""f1v)'>~1J:'TlN
lifO Alr,,-
S(.o,III/Ft.",Jv-"(j J...t'tl A,....}I 5-t f f.1 Dd-/POv/o~C/
J'/111'\{J J VI.\7 I Av~I $L I J 0 urJ ~Dv J Dt-v .
Dc;\.
350 .
/00
/,0
2 00
____+-~()0
STAGE I I
STAGE II I
LATE STAGE III
o--~
0--------0
J
300 .,4·--4...----4J.-.l!~~rAb_+-----_H:___---
250
\
\-\
\200 -l--------+----fl-.'--------lr---~--_;kJ.q_----
50 -1f--------.l~......-A:-+____:~--~----t_--___jr_-----,0
-.~
1-.
Z
I
~:'
~:150 Jil----------t----~/i_I_t_"i-f'---.OF=-=4
o I "~~I :
~~,,....',I
100 ~~-',~~~:___--_+_---;.t.::.-.-G-~~-~r__~~_r_--~-
.-
.....
-
.....
.-
-Figure 1-4.Estimated with-project mean monthly turbidity values at Gold
Creek compared to natural values (with-project values from
APA 1985,natural values from ADF&G 1983g).
1-9
-
-
-
-
.....
-
-
(Har2:a-Ebasco 1985).As in the case of TSS,turbidity is positively cor-
related with flow and is seasonally variable.Turbidities will not fluctuate
over the course of the year during operation of the project as much as under
natural conditions.On the other hand,with-project turbidities,like TSS
concentrations,will be higher than those under natural conditions during the
fall and winter but lower during the spring and summer.
TempE!rature is interrelated with flow,TSS,and turbidity.Actually,changes
in the latter three are largely dependent upon climatic temperature which,in
turn 11 is the main variable affecting water temperature.Thus,it is logical
that all four variables exhibit the same seasonal trends.Temperatures in the
middlle Susitna River range from DoC during winter to 12-13°C in the summer.
The project,however,will store large volumes of water and then release it at
relatively constant discharge rates resulting in increased temperatures during
the ~tinter and lowered temperatures during the summer.The effect will become
more pronounced as subsequent stages are completed.However,changes in
tempE~rature profiles unlike those of flow,TSS and turbidity,will not occur
alonu the whole length of the river below the site location.The further
downstream water travels the more it will be influenced by ambient air temper-
atures until project-related influences are negligible.Figure 1-5 shows the
impacts of the project on temperature regimes.Greater differences between
natural and with-project temperatures occur in the upper and middle reaches
(RM1:30)than at the lower end (RM 100)of the middle Susitna River.Further-
more,the later stages of the project cause greater deviations from natural
watel"temperatures because of the greater vol urnes of water stored.
The discussion to this point has centered on mainstem temperatures.However,
tempE!ratures in peripheral fish habitats,such as sloughs and side channels,
can differ from those in the mainstem depending upon the amount and tempera-
tures of upwelling,climatic conditions,and the volume and temperatures of
rnai nstern water enteri ng these habitats when berms are overtopped.Tributary
temperatures,on the other hand,wi 11 not be affected by the project.
Generally,temperatures of sloughs and side channels that are not overtopped
will be lower in summer than mainstem temperatures (APA 1985).This is a
1-10
LEGEND
--NATURAL
------.STAGE I
---STAGE II
---LATE STAGE III
J A S
RMJ30
M J J A S
1981
12
10
8
u 6
(J)
ww 40::
0
Wa 2
0 RMIOO
M J
12
10
8
u 6-(I)
1LI 41LIa::
C)aua
2
0-
-
.......
r-
!
-i
Figure 1-5.Estimated with-project temperatures at two river miles (RM)
at three stages of development compared with natural tempera-
tures (modified from APA 1985).
1-11
-
result of upwelling in these habitats and tributary input,the temperatures of
which are usually colder than mainstem temperatures.On the other hand,
higher than normal flows in winter caused by the project may contribute to the
freezing of some leads that are normally open as a result of relatively warm
winter upwelling.
-
..-
-
-
As discussed in Vol ume I,ice processes may contribute to other impacts on
peripheral habitat.Thus,ice processes are important influences on fish
habi tat in the Sus itna Ri ver.Because of the effects of the proj ect on
temperature regimes,ice cover will change both spatially and temporally as
illustrated in Figure 1-6.Whereas ice forms naturally over the entire middle
river'in winter,the release of relatively wann water from the project will
result in open water below the dam site all year long.The distance down-
stream that open water will exist,however,will vary according to the stage
of de!ve10pment.At the completion of Stage I,the middle Susitna River will
be ic:e free from the Watana Dam downstream to RM 139.On the other hand,the
section of ice-free river will extend from the Devil Canyon Dam (RM 150)to RM
114 ~,;th the completion of Stage III.Furthermore,the length of time that
ice E~xists on the middle river will be altered by the project.Figure 1-6
shows that ice normally begins forming at Talkeetna (RM 100)in mid-November •
Melt-off is complete toward the end of May.However,the period that ice
exists on the middle river will be m'arked1y shortened until the completion of
Stage:III when ice cover will exist only from early January to the middle of
March.
Fish Resources in the Middle Susitna River
Existing fish resources are described in detail in numerous reports (see,for
-.example,APA 1985).Volume I of the IFRR summarizes these resources and
describes important physical variables that influence them.We briefly
reite~rate here what those resources are.The approach taken in developing a
methcldo10gy which establishes the relationships between these resources and
instream flow processes is described in the next section.
Approximately 20 species of fish inhabit the Susitna River at one time or
another during their life histories (see Fig.I-I).These species include
1-12
1 1 1 J 1 I t i 1
(A)
'-"
Duration of Ice -Covered Period on MI~dl.Susitna River
I Nov I Dec I Jan I Feb I Mar I Apr I May I
t-'4 Natural ~I
~Staie I ~
"StOie 11 >t
Stag,m >tt..
®
......
I
I--'
W
Maximum Upstream Extent of Ice Cover on Middle Susitno River
River Mile River Mile
~OO '1 4 1;3 I r9 I~O
Natural
I ~
Stage I 139
I ~
Stage II 133
~~
Stage m 114
I w
Figure 1-6.Extent and time of ice cover on the middle Susftna River
under natural and with-project conditions.
....
-
-
-
-
-!
commercial,sport,subsistence and non-game fish.The most important in terms
of recreational and commercial interests are five species of Pacific salmon,
rainbow trout,Dolly Varden,Arctic grayling,and burbot.
The goal of the Alaska Power Authority in identifying environmentally accept-
able flow reg"imes for the proposed project is to maintain eXisting fish
resources and levels of production.It is possible that this can be accom-
plished by the selection of appropriate operational flow and/or temperature
regimes.To do this,it is necessary to quantify the response of fish in the
Susitna River to incremental changes in mainstem discharge,temperature,and
wa ter'qual i ty.
Scope of the IFR Studies
The IFR studies were undertaken to establish the relationsh"ips between physi-
cal variables,fluvial processes and fish resources in the middle Susitna
River.This represents an extremely complex problem because of the number of
environmental variables involved and the number of species of fish which
inhabit the middle Susitna River.It is necessary,therefore,to reduce the
scope!of work by focusing only on the most important physical variables,and
by cCilrefully identifying the important fish resources whi ch are most sensitive
to project-related changes in those variables.
WherE!aS physical parameters can be quantified relatively easily,quantifying
the r"esponse of fish to changes in these parameters requires the selection of
an appropriate response variable(s).To avoid many of the uncertainties
associated with correlating fish populations with environmental parameters,
habitat is often used as a response variable (Stalnaker and Arnette 1976,
Olsen 1979,Trihey 1979).Accordingly,habitat analysis is used in the IFR
stud1ies as an indicator of how fish populations respond to changes in fluvial
procE~sses.When using fish habitat as the response variable,the direction
and magnitude of change in habitat availability or habitat quality is used to
indicate the response of the population.Although the relationship between
habitat and population is not necessarily linear,it has been found to be
positively correlated (Binns and Eiserman 1979,Wesche 1980,Loar 1985).
1-14
-
-
-.
Six habitat types were identified within the middle Susitna River (ADF&G
1983b,Klinger and Trihey 1984).These are:1)mainstem,2)side channels,
3)side sloughs,4)upland sloughs,5)tributaries,and 6)tributary mouths.
Furthermore,depending upon mainstem stage,some of these habitats may be
transformed from one type to another (Kl inger and Trihey 1984).The impor-
tance of each habitat type varies with species and life stage.This neces-
sitated the selection of evaluation species/life stages,based on their
importance and sensitivity.In this way,the.species and habitats analyzed
were reduced to a manageable number.Each evaluation species/life stage was
carefully sel ected so that if concerns for each were addressed,then concerns
for other species would be "implicitly incorporated into the analysis.There-
fore,the analysis was simplified but,at the same time,remained compre-
hensive.
Evaluation species/stages were selected by determining the species that are
most sensitive or important to cormllercial,subsistence,and recreational
inter'ests,and by determining the life stages that are most vulnerable to
predicted environmental perturbations associated with the project.This
sensitiVity analysis proceeded according to the species/life stages likely to
be pr'esent in affected habitats.Of the six habitat types,only three will be
signi.ficantly affected by alterations in physical variables.These are
mainstem,side channels,and side sloughs.These habitats are used mostly by
anadr'omous species;resident species are present in relatively low densities.
There!fore,modeling the use of mainstem,side channels,and side sloughs by
salmon was considered to be of primary importance.
On ly two speci es of salmon,chi nook salmon and chum salmon,were used as
evaluation species.The rationale for this decision was that the three
habitat types most susceptable to project-induced effects are used by salmon
for migration,spawning/incubation,and rearing/overwintering.Of these three
life stages,only migrating adults are not critically sensitive to the kinds
of physical changes that will likely be associated with the project.On the
other'hand,chinook salmon rearing/overwintering is one of the most important
uses of side channel and side slough ·habitats.Thus,chinook rearing/over-
wintE~ring was included as an evaluation species/stage.These same two habi-
tats are also used intensively by chum and sockeye spawning/incubation,but
1-15
i~
-
-
,~
....
,....,
I
~
,
-
because chum salmon are far more abundant "in the middle Susitna River than
sockeye salmon,chum spawn"ing/incubation was chosen as another evaluation
speci1es/stage.
Other species are important in the middle river but their use of and sensi-
tivi~y in the habitats affected by the project do not warrant detailed analyt-
ical analyses.If habitats used by chum and chinook salmon are incorporated
into the quantitative methodologies,then concerns about other species can be
addressed subjectively.Consequently,this report is presented in sections
that quantitatively analyze,where possible,chinook rearing/overwintering and
chum spawning/incubation,and subjectively address concerns for other species.
7
The analytical methodology use for chinook and chum salmon is based on the
premise that available habi t can be quantified and then standardized to an
equivalent amount of optimal habitat known as weighted usable area (WUA).
This technique allows aifferences in habitat quality by incorporating
habitat suitabi 1ity criteria "i nto the ana lysi s.The analysis is performed
usingl the "instream flow incremental methodologies (IFIM)as discussed by
Milhous et aT.(1984).Because instream flow is a driving variable which
eithe:r di rectly or indi rectly affects water temperature and water qual i ty,the
response of WUA to incremental changes in ma i nstem di scha rge is the focal
point of the quantitative relationships analysis.
Volume I of the IFRR identified the physical parameters,habitat types,and
evaluation species/life stages discussed above.It also presented rankings of
the I~elative importances of each,introduced the methodology for quantifying
available habitat (WUA)as it responds to changes in mainstem discharge,and
discLlssed other variables which,although not quantifiable at that time,
never·theless may be important criteria in determining the response of fish
populations in the middle Susitna River to fluvial processes.
Vo 1 ume II provi des a 1ogi ca 1 sequel to Volume 1.It provi des a refi ned
analjfsis of that which was presented in Volume I.Whereas Volume I identified
key processes and establ i shed the approach for quantifyi ng the response of
fish habitat to changes in streamflow,Volume II provides the basic framework
of a useable methodology for application in the middle Susitna River.
1-16
-
One important procedure used in Volume II is the extrapolation of model output
to the entire middle river.To extrapolate results obtained at individual
sites to a system-wide response,the concept of representative groups of study
sites was introduced in Volume I.The entire middle river was divided into
172 specific areas,each of which was characterized structurally and hydrau-
lically.These areas were then categorized into 10 representative groups,
based on morphologic,hydraulic,and hydrologic similarities.Thus,the
entire length of the middle river has been divided into representative groups
of study sites.This replaces the longitudinal,representative reach approach
commonly used in homogeneous,single-channel systems,a change from tradition-
al mlethodology necessitated by the existence of split-and multi-thread
channels in the middle Susitna River.Included in the analysis was the
phenomenon of habitat types transforming from one type to another according to
breaching flows.Within each representative·group there exists both modeled
and non-modeled sites.Modeled sites are those that have been extensively
surveyed.In Volume II results of habitat response analyses are extrapolated
from modeled sites to their respective representative groups using areal
proportionality.System-wide responses are then estimated by integrating the
individual responses of all 10 representative groups.
Volume II also defines limits and boundaries for the model and describes how
other'non-modeled parameters could be incorporated.The main objective of
Volwne II is the refinement of principles elucidated in Volume I into an
integlrated procedure for use during the settlement process.It is hoped that
the IFRR will be useful in arriving at a negotiated settlement which incorpo-
rates a comprehensive understanding of the effects of various project design
and operation scenarios on fish habitat.
1-17
r
-!
....
II.RESPONSE OF JUVENILE CHINOOK HABITAT
TO MAINSTEM DISCHARGE
This section evaluates the weighted usable area (WUA)group curves for
portions of the river,descr'ibed by Steward et al.(1985),and discusses how
the.Y may be used to estimate the system-wide response of juvenile chinook
habitat in the middle Susitna River to variations in mainstem discharge.This
procedure requires an interpretation of the information obtained by the
modeling techniques and of the suitability criteria on which the curves are
based.The significance of other factors not included in the model is
examined and suggestions on how they may be incorporated are presented.
Juvenile chinook abundance and distribution data are evaluated to ascertain if
they suitably reflect the WUA forecasts for portions of the river.
Chinook Salmon Biology in the Middle Susitna River
Distribution and Abundance
APA (1985)and Jennings (1985)summarized the species biology and habitat
utilization of salmonids in the Susitna River drainage.However,a brief
outline of the biology of chinook salmon in the middle Susitna River is given
to highlight life stages and periods during the year that chinook may be
influenced by altered with-project flow,temperature and water quality re-
gimes.
Chiinook spawning in the middle Susitna River generally accounts for less than
5 percent of the total Susitna River basin escapement and occurs entirely in
clE!arwater tributaries.Of those fish that do migrate into the middle Susitna
River,more than 90 percent spawn in Indian River (RM 138.5)and Portage Creek
(RM 140)(Barrett et al.1984).Spawn"ing generally peaks between the last
weE!k of July and the first week of August.However,the passage of spawning
ch"inook into these two principal tributaries is not likely to be impeded at
lm~mainstem discharges (Trihey 1983).Consequently,chinook spawning and egg
incubation is not critically sensitive to alteration in mainstem discharge and
is not included in the analysis.
II-I
-
-
-
.-
Chinook fry emerge from the tributary spawning gravels in late March to
midi-April and remain near their natal "areas for one to two months.Possibly
as a result of territorial behavior and limited carrying capacity of the natal
areas,some juveni 1es then initiate a downstream movement and population
densities begin to increase in mainstem-associated habitats in late July.
Some 0+juveniles move downstream and leave the middle Susitna River entirely,
realring in the lower river or entering Cook Inlet.Large numbers of 0+
chinook appear to outmigrate from the middle Susitna River during high
mainstem discharges (Hale 1985).In the lower Susitna River the highest
densities of 0+juveniles were collected in the deep,low velocity,clearwater
of tributary mouths (Suchanek et al.1985).It is unclear whether those 0+
outmigrants that do enter Cook Inlet survive.However,age 0+outmigrants may
fonn a transition check or other similar tightening of the circuli on their
scales which may be interpreted as a freshwater annulus thereby underestimat-
inU the importance of this age class (Roth and Stratton 1985).Richards
(1979)showed that 72%of the adul t scales analyzed from the Deshka Ri ver
dur"ing 1978 were 0+ocean outmigrants,whereas creel census scale samples had
c1i:lssed them primarily as 1+.
Of the habitats associated with the mainstem of the middle Susitna River,0+
chinook densities are highest in the side channels,particularly during July
and August.Side sloughs and upland sloughs become more important in Septem-
bel"through November as juvenile chinook seek out suitable overwintering
habitats.Population estimates for chinook fry at sloughs and side channels
dUll';ng 1984 are given in Tabl e II-I.From May through November approximately
60 percent of the juvenil~chinook in the middle Susitna River utilize the
tr'ibutary habitats and 40 percent use the mainstem-associated habitats (Figure
II··1).
Thl:!majority of juvenile chinook in the Susitna River go to sea after spending
f'~l:!winter in freshwater.This is typical of juvenile chinook in other
~Alaskan rivers (Burger et al.1983,Kissner 1976,Meehan and Snift 1~62,Waite
19:79).Age 1+juveni les outmi grate from the middl e Susitna River from early
-II-2
-
,~
Table 11-1.Chinook salmon fry,population estimates by site for sloughs and side channels
surveyed in the Susitna River above the Chulitna River confluence,1984 (from Roth
and Stratton 1985).
Sampling Branding Recapture Estimate Population
Site Dates Dates Method Estimate
Upper Side Channel 11 7/19 -8/1 7/30 -8/2 Schaefer 3,420
Side Channel 10 7/16 -7/19 7/17 -7120 Schaefer 7,630
Moose Slough 8/8 -8/11 8/9 -8/12 Schaefer 4,990
Slough 22 9/8 -9/13 10/8 Petersen 47,050
Slough 19 8/28 9/26 Petersen 4,500
Side Channel 21 9/24 -9/26 CPUE Index 3,700
Slough 20 10/8 -10/12 CPUE Index 13,800
II-3
-,c 1 -J )1 j .~J )-~1 J ))1 }
SlouQh 9
SIDE
CHANNELS
/
6.7~UPLANO SLOUGHS
Sid,Chonn.'10
SIDE SLOUGHS
Fly.T,lbulo,l.."""
Combln.d 10.4Y."'".
Whisk,,.C,uk
SlouOh
----I----------~~.olbow 9n.I Mol~'I'''!1 II O.bow On.SlouOh 22 I 10.7 ~Id'Chonn.1
9.3 Y.8.2%\~~10'17.9%
\ //~Tw.lv.SII ..Elohl .S"'~O·~~/'\I Co",bln.dComb,••d.•SlouOh 22
..........
I.po
COMBINED MACROHABITAT
TYPES
Fl gure II-1.Density d1strlbution of juvenile chinook salmon by macro-
habitat type on the Susitna River between Chul itna River
confluence and Devil Canyon,May through November 1983.
Percentages are based on mean catch per cell (from Dugan,
Sterritt and Stratton 1984).
-
-
-I
May to mid-July.Outmigration from the lower river peaks in mid-June and is
completed by early August (Suchanek et a1.1985).
Growth of Juvenile Chinook
In the middle Susitna River,chinook fry emerge from the gravel in their natal
tributaries at about 37 mm long.By the beginning of June they have grown to
44 mm and by early October have a mean length of 64 mm.Chinook fry collected
in the lower Susitna River are on average from 2 to 10 mm 1arger duri ng the
same time period (Figure II-2).Growth in the tributaries was greater than
growth in the side channel and side sloughs during 1984 (Table II-2).Growth
of 0+chinook in the Deshka and Talkeetna Rivers during the same time period
was significantly higher than the middle Susitna River (Table 11-3).
DUI"ing the winter of 1984-85,juvenile chinook in the middle Susitna River
exhibited negligible growth,averaging only a 6 mm increase in length from
64 mm in early October to 70 mm by mid-May (Stratton 1985).However,there
was then a surge of growth in the spring.Smo1ts collected at the Talkeetna
outmigrant trap in 1985 were averaging 89 mm by the end of June.Ninety mm
was the average length of outmigrating 1+chinook in previous years (ADF&G
1983a).Figure 11-3 gives the length/weight relationship for both 0+and 1+
ch'inook salmon collected at the Talkeetna outmigrant trap during 1984.
Modeling of Juvenile Chinook Habitat
To assess the influence of changes in fluvial processes on rearing juvenile
chinook in the middle Susitna River,a mechanism is necessary to quantify
changes in habitat availability.As outlined in the Introduction,one of the
principal effects of the project will be the alteration of the flow regime in
the river.Because of the direct relationship between flow and habitat
av<ai1abi1ity,the Instream Flow Incremental Methodology (IFIM)was used to
estimate weighted usable area (WUA)for juvenile chinook rearing.Rearing
habitat was modeled using three variables:velocity,depth and cover.Field
data were collected by ADF&G at a number of sites to develop habitat suitabi1-
i~y criteria for these variables.
II-5
.H!li!!!Il!J!...Ill_....,
-
CHINOOK 0+1984
-
.....
-
-
-
-
80
75
70-~65:::i-:t:
t-o 60zw
-l
Z 5S~w
:i
50
4S
40 +---,.....--.....,....---,...----....-----r------r---.....-----I
L MAY .E JUN L JUN E JUL L JUL E AUG L AUG E SEA..SEP-E OCT
SAMPU NG PERIOD
.~
Figure 11':'2 •Chinook salmon (age 0+)mean length and range of lengths by
sampl in9 period for fish collected in the lower and middle
reach of the Susitna River,1984 (from Roth and Stratton
1985)•
II-6
J ~._j 1 -}]1 1 )]J 1 J ))
Table 11-2.Number of fish,mean l~ngth,and range of lengths for age 0+chinook salmon by sampling period on the Susitna River between
Talkeetna and Devil Canyon,1984 (from Roth and Stratton 1985).
Talkeetna Station Mainstem middle Susitna Rivera Indian River
Sampling
Period n Mean Range n Mean Range n Mean Range
May 2 55.5 53-58 60 40.8 35~45 *
June 1-15 54 48.6 36~66 *--*
June 16-30 475 53.0 37-70 *--*
July 1-15 538 56.2 38-75 100 47.8 38-67 50 48.9 42-64
Juiy 16-31 1131 55.5 37-80 50 52.2 42-69 50 54.9 47-67
August 1-15 748 57.9 40-90 50 52.4 40-77 100 58.8 47-90
August 16-31 612 59.5 39-95 100 56.1 43-72 100 61.1 49-80
......September 1-15 119 62.7 45-91 100 57.6 47-88 100 63.8 47-90
......
I September 16 -October 15 13 60.8 51-90 200 61.0 45-90 300 65.5 50-89'""..Not sampied •
b Includes all mainstem,slough and side channel sites sampled during the JAHS study in the Susitna River between Cook Inlet and the
Chulitna River confluence.'
}))J i 1 ))1 )1 1 J ))I
Table 11-3.Mean length and range of lengths for age 0+chinook salmon by sampling period in the lower reach of the Susitna River,
1984.
Talkeetna River Deshka River Mainstem Lower Susitna River a
Sampling
Period n Mean Range n Mean Range n Mean Range
May *--77 42.7 36-49 *
June 1-15 0 - -
21 42.4 40-46 74 48.5 34-63
June 16-30 26 52.2 43-64 56 55.7 46-69 63 52.0 36-70
July 1-15 159 56.0 44-70 236 66.8 52-83 84 54.5 39-74
July 16-31 155 56.1 40-74 201 69.7 52-93 171 58.1 39-80
August 1-15 257 60.7 44-84 53 74.4 60-91 330 58.9 40-82
August 16-31 114 65.2 51-84 65 71.7 55-89 238 61,5 42-94
September 1-15 0 --15 77.9 69-88 52 66.8 52-95
I-i....
I September 16 -October 15 *- -
102 76.0 68-85 53 73.2 51-92co
..Not sampled.
b Includes all mainstem,slough and side channel sites sampled during the JAHS study in the Susitna River between Cook Inlet and the
Chulitna River confluence.
....LINEAR REGRESSION C:HINOOK SALMON
-6...,.------------------------------,
o c
c Actual Dota
Regression Line
a
o8
in y =-12.71 +3.2.In X
5
1
-
907050
o +--....;-.---r----~---__r-----_r_---~---___l
30-Total length in millimeters
--
Figure II-3.Linear regression of the weight/length relationship for
juvenile chinook salmon collected at the Talkeetna stationary
outmigrant traps,1984 (from Roth and Stratton 1983).
-
-
II-9
-------_......-------------....--.....,..--"'....P----------------
.....
.-
Suitability Criteria
Velocity.Velocity is a function of flow regime and is an important factor
influencing the availability of juvenile chinook habitat in the middle Susitna
River.The relationship between velocity and juvenile fish distribution
depends on fish size because as they become lclrger,they are able to.move into
faster,deeper water.
Suchanek et al.(1984)report that in the middle Susitna River juvenile
chinook prefer lower velocities and shallower depths in turbid water than in
clear water.Suitability criteria indicate that opt"imul11 velocities occur
between 0.05 and 0.35 feet per second (fps)lin water with turbidities greater
than 30 nephelometric turbidity units (NTU),and between 0.35 and 0.65 fps in
water of less than 30 NTU.Literature values typically indicate that optimal
velocities in clear water are less than 0.5 fps (Everest and Chapman 1972,
Stuehrenberg 1975,Burger et ale 1982,Bechtel 1983).Although the chinook
velocity criteria from the literature were developed from data collected in
clear water,they are more similar to the middle Susitna River criteria for
turbid water.This is because of differences in field methods employed by
ADF&G and other investigators (EWT&A and Entrix 1985).However,it should not
be assumed that velocities less than 0.35 fps in the middle Susitna River are
unfavorab 1e to juvenil e chi nook in cl ear Welter.Consequently,the optimum
velocity range of the clear water suitabili~y criteria have been extended to
include velocities between 0.05 and 0.65 fps (Fig.11-4).The reasons for the
preference of juvenile chinook for lower velocities in areas of higher
turbidity may be twofold:1)at faster currents there is a lack of visual
cues to maintain position;and 2)at higher velocities it is more difficult to
detect drifting prey items.
Water Depth.Water depth is determined by streamflow,channel form and
streambed materials.Rearing juvenile chinook salmon in the middle Susitna
River use a wide range of water depths (ADF&G 1984)as indicated by the open-
ended suitabil ity curve in Figure II-5.Provided that other microhabitat
conditions are suitable,juveniles tend to prefer depths exceeding 0.15 feet
to an equal degree.These observations have been corroborated by other
habitat utilization studies of juvenile chinook salmon (Burger et ale 1983)•
II-10
-
VELOCITY SUITABILITY CRITERIA FOR JUVENILE CHrNOOK SALMON
3.02.5
U1f01d
0.42
1.00
1.00
1.00
0.80
0.60
0.38
0.25
0.15
O.CIT
0.02
0.01
0.00
2.01.5
~EGENO
-_.-Tumid
----aear
Clear _telr less than 5 NTU
Turtlld _t4!f'SO to 200 NTU
5UITABlUTY (5,,)
vetoctty Clear
0.00 0.42
0.05 1.00
0.20 1.00
0.35 1.00
G.5O 1.00
0.65 1.00
0.80 0.68
1.10 0.44
1.40 0.25
1.70 0.18
2.00 0.12
2.30 0Jl6
2.60 0.00
1.00.5
0.8
1.0
0.6
0.2
OA
0.0 +-----....----r-----r--.---,-......;;;;;;::..===-r-----,
o
.-
-
VELOCITY (ftIsec]1
-
-Figure II-4.Velocity suitabil ity criteria used to model juvenile chinook
habitat (WUA)under clear and turbid water conditions in the
middle Susitna River (from Ste\l'/ard 1985).
II-ll
1 ]))J )1 j 1 l J
DEPTH SUITABILITY CRITERIA FOR JUVENILE CHINOOK SALMON
3.0
DEPTH SUITABILITY (Sel>-
0.00 0.00
0.14 0.00
nil:1.00v.,,,,,
10.00 1.00
2.01.0
r Ii'i~iii •10.0
1.0
.9
.8
.7
~.8
~
~.5
iii
~
~5 .4
I--'f VI
I.......
N .3
.2
.1
0 .
0
DEPTH (h)
Figure II-5.Depth suitability criteria used to model juvenile chinook
habitat (WUA)under clear and turbid water conditions in the
middle Susitna River (from Steward 1985).
"""'
-
,~
-
Cover.Cover is extremely important to rearing anadromous sa1monids to avoid
predation by other fish,birds,and terrestrial animals and to avoid unsuit-
able velocities.Predation can cause significant mortalities among rearing
juveniles,particularly after emergence from the gravel (Allen 1969).Cover
requirements vary diurnally,seasonally or by species and fish size (Re~ser
and Bjornn 1979).In the middle Susitna River,a well-developed riparian zone
does not exist along the edges of most side c:hanne1s and side sloughs because
of ice processes and flow variations.In the absence of vegetation,banks are
unstable and,hence,do not become undercut.Large organic debris is rare in
side channels and only small amounts are present in side sloughs.Hence,
riparian vegetation,undercut banks and large!organic debris are not forms of
cover typically available for juvenile chinook in these habitats.These types
of cover are more prevalent in upland sloughs.
Cover for juvenile chinook in the middle Susitna River is more typically
provided by suitably sized substrate and turbid water.Field observations and
catch data from ADF&G indicate that juvenile chinook salmon abundance differs
between turbid water and clear water.Catch rates at turbidities greater than
30 NTU were significantly higher (p =<0.001)than at turbidities less than
30 NTU in cells without any type of object cover.Thus,in the absence of
object cover,turbid water is used for cover by rearing chinook salmon
(Suchanek et al.1984)•.The utilization of turbidity as cover appears to be
most prevalent during July and August,following redistribution from the
tributaries.When a turbid side channel becomes non-breached and transforms
to a clearwater slough,the number of juvE!nile chinook per cell typically
decreases (Suchanek et aT.1984).When the water clears,some juvenile
chinook in turbid pool habitat will school and move up to riffles near the
upstream end of the site where they seek out object cover.These different
preferences for the same type and percent of obj ect cover under clea rand
turbid water are reflected by the derivation of two sets of suitabil ity
criteria for cover (Table 11-4,Fig.11-6).
Extrapolation of Modeled to Non-modeled Site~
The modeling techniques used and the extrapolation of the results to provide a
response for the entire middle Susitna River were outlined by Steward et al.
(1985).WUA functions were derived which define the relationship between
II-13
)-J ]-J -1 )~~c-l ))~~-)1 1 ]
Table 11-4.Cover suitability criteria recommended for use in modeling juvenile chinook habitat under clear and turbid water
conditions.Sources:Suchanek et ale 1984;Steward 1985.
Percent No Emergent Aquatic Large Rubble Cobble or Debris &Overhanging Undercut
Cover Cover Vegetation Vegetation Gravel 3"-5"Boulders >5"Deadfall Riparian Banks
Clear Water (Suchanek et al.-1984)
0-5%0.01 0.01 0.07 0.07 0.09 0.09 0.11 0.06 0.10
6-25%0.01 0.04 0.22 0.21 0.27 0.29 0.33 0.20 0.32
26-50%0.01 0.07 0.39 0.35 0.45 0.49 0.56 0.34 0.54
51-75%0.01 0.09 0.53 0.49 0.63 0.69 0.78 0.47 0.75
76-100%0.01 0.12 0.68 0.63 0.81 0.89 1.00 0.61 0.97
Turbid Water (EWT&A and WCC 1985)1
..........0-5%0.31 0.31 0.31 0.31 0.39 0.39 0.46 0.26 0.44
I......
..j:>oo 6-25%0.31 0.31 0.39 0.37 0.47 0.51 0.58 0.35 0.56
26-50%0.31 0.31 0.46 0.42 0.54 0.59 0.67 0.41 0.65
51-75%0.31 0.31 0.52 0.48 0.62 0.68 0.77 0.46 0.74
76-100%0.31 0.31 0.58 0.54 0.69 0.76 0.85 0.52 0.82
1 Multiplication factors:0-5%-4.38;6-2%-1.75;26-50%-1.20;51-75%-0.98;76-100%-0.85
J )1 --1 1 }>1 -}-~-J J -J J 1 j
2 3
No Cover Emerc~.nt Aquatic
VeQ.totion V.~etation
0.5
9
Uncltrcut
Banke
O.~0.1
8
Overhanging
Riparian
0.15 0.1
7
Debrie a
Deadfall
0.&0.1
6
Cobble or
Bouider ..
over a
0.00.1
~
Rubb\,
3·5
0.50.1
4
Lorge
Grovel
0.50.1O.~0.10.50.10.1
o •0 tt'tifblt"nWttitiftlfltr···
1.0
I i
CLEAR
TURBID
0.6 -I I
Percent Cover
0.1 0-5
X O'6~0.2 6 -25
W 0.3 26 ·50
0 0.4 51 ·75Z-0.5 76 ·100
>-
I-
..J-0.4......lD......«I l-t-'
(}1 ::::>
iii
0.2
PERCENT COVER BY COVER TYPE
Fi gure II -6.Cover suitabil ity criteria used to model juvenile chinook
habitat (WUA)in the middle Susitna River.Separate criteria
are presented for clear and turbid water conditions (from
Steward 1985).
r-
I
I
mainstem discharge and chinook rearing habitat potential at 20 side slough and
side channel modeling sites in the middle Susitna River.The mainstem is not
used by juvenile chinook for rearing.Mainstem margins and tributary mouths
will be relatively unaffected by project-induc:ed changes.
Conventional methods of extrapolating WUA in single channel rivers based on
the concept of continuous homogeneous subsegrments represented by i ndi vi dua 1
modeling sites are not applicable to braided rivers like the Susitna River due
to large spatial variations in hydraulic and morphologic character (Aaserude
et al.1985).This prompted the development of an extrapolation methodology,
outlined by Steward and Trihey (1984),which weights WUA values developed for
each modeling site according to the proportion of the middle reach possessing
similar hydrologic,hydraul ic and water clar'ity attributes.The results of
the habitat modeling analyses are WUA forecasts for sites which frequently
transform from one habitat type to another (i,.e.side slough to side channel).
The static quality implicit in the habitat type concept of Klinger and Trihey
(1984)made it inappropriate as a method of stratifying the river for
extrapolation purposes.
The concept of representative groups as a further set of distinct areas of the
middle Susitna River and the criteria used by Aaserude et al.(1985)to define
them ensures that habitat transformations are~addressed in the stratification
process.Aaserude et al.(1985)delineated 172 specific areas of the middle
Susitna River which were divided among ten representative groups.They are
listed with location of their associated modeling sites in Table 11-5.The
extrapolation of modeling results to non-modeled specific areas and their
combination into WUA response function for each representative group has been
described in detail by Steward et al.(1985).
However,proper interpretation of the WUA curves requires a review of the WUA
modeling process,as well as the method uSE~d to extrapolate the models to
non-modeled sites.The Representative Group WUA curves are the sums of the
WUA curves for the specific areas,some modE~led and some non-modeled within
the groups.The WUA curve of a modeled site is the sum of the WUA curves of
the cells comprising the site.A typical cell is shown in Figure 11-7.It is
at this Ilcellular"level that WUA is actually modeled.
11-16
Table 1I-5 Primary hydrologic,hydraulic and morpl"ologic
~h~racterisitcs of representative groups ident-
lfled for the middle Susitna River.
-REPRESENTATIVE NUMBER OF
GROUP SPECIFIC AREAS OESCR I PTl ON
HA8ITAT
I'IlOELING
SITES
-
11
III
IV
v
Vl
VII
VII[
IX
X
19
28
18
21
9
13
1
24.
21
13
Predominantly upland sloughs.The specific Ilreas comprising this group are
highly stable due to the persistence of nCln-breached conditions (1.e ••
possess high breaching flows).Specific aru hydrauli cs are characterized
by pooled clear water with velocities frequt!ntly near 0.0 fps and depths
greater than 1.0 ft.Pools are commonly connected by short riffles where
velocities are less than 1.0 fps and depths lire less than 0.5 ft.
This group includes specific areas COlllllOn111 N!ferN!d to as side sloughs.
These sites are characterized by re1a·tive1y high breaching flows
(19.500 cfs).clear water caused by upwe'lling groundwater.and large
channel length to width ratios (15:11.
Intermediate breaching flows and relatively broad channel sections typify
the specific areas within this Representatfvl~Group.These sites are side
channels which transform into side sloughs Ilt mainstem discharges ranging
from 8.200 to 16,000 cfs.Lo-er breachinl~flows and smaller length to
width ratios distinguish these sites from those in Group II.Upwelling
groundwater is present.
Specific areas in this group are side chanl~e1s that are breached at low
discharges and possess intermediate mean reach velocities (2.0-5.0 fps)at
a mainstem discharge of approximately 10,000 cfs.
This group includes mainstem and side channel shoal areas which transform
to clear water side sloughs as mainstem flows recede.Transformations
generally occur at moderate to high breaching di~charges.
This group is similar to the preceding one in that the habitat character of
the specific areas is dominated by channel morphology.These sites are
primarily overflow channels that parallel tbe adjacent mainstem.usually
separated by a'sparsely vegetated gravel bar'.Upwelling groundwater mayor
may not be present.Habitat u'ansformations within this
group are variable both in type and timing ~If occurrence.
These specific areas are typically side channels which breach at variable
yet fairly low mainstem discharges and exhibit a characteristic riffle/pool
sequence.Pools are frequently large backwater areas near the mouth of the
sites.
The specific areas in this group tend ttl dewater at relatively high
mainstem discharges.The direction of fla-,at the head of these channels
tends to deviate sharply (30 degrees)from the adjacent mainstem.
Modeling sites from Groups II and III pClssessing representative post-
breaching hydrau1 ic characteristics are used to model these specific areas.
This group consists of secondary malnstem channels which are similar to
primary mainstem channels in habitat character,but distinguished as being
smaller,and conveying a lesser proportion of the total discharge.Speci-
fic areas in this group have low breaching discharges and are frequently
similar in size to large side channels.but have characterfstic mainstem
features.such as relatively swift velocitillS ( 5 fpsl and visibly coarser
substrate •
Large mainstem shoals and the margins of malnstem channels which show signs
of upwelling are Included in this representative group.
11-17
107.6L,llZ.SL
101.4L,11J.1R,
126.0R.144 .4L
101.ZR,128.8R,
l32.6L,141.4R
112.6L,137.7L
134.9R.136.0l
141.6R
133.8L,136.3R
119.2R
13Z.6L,144.4l
IOl.SL.147.IL
10S.Bll,l19.lll,
138.7IL.l39.41L,
133.BIR
-
Vi =velocity (ftlsec)for ilh cell
di =depth (ft)for ith cell
wi =width (ft)for ith cell
Ii =length (ft)for ith cell
-
,~
.....4
PHAEJSIM
5 6
FLOW
Figure II-7.Sampling design for PHABISM modeling sites (from Steward et
a 1.1985).
II-IS
-
-
-
-
-
-
-
We need to examine the process by which the WUA response of a cell is cal-
culated at a particular flow.Hydraulic models,or field observations,
provi de the surface area,representative water depth,and velocity for the
cell.Generally,the area of the cell dOlesn't change with flow,and is
considered a constant.Therefore,the hydraulic module of the model reduces
to two variables,water depth and velocity.The habitat module adds one more
cell variable,cover,which contains information concerning the type and size
of instream objects present within the cell.Resident and juvenile fish
studies generated suitability criteria functions for these three variables,
which describe their degree of suitability as juvenile.chinook habitat.The
suitability of the cell is simply the product of the probability of use
relative to depth,the probability of use relative to velocity,and the
probability of use relative to cover.Since each of these probability factors
ranges from zero (no use)to one (highest use),their product ranges from zero
to one.The WUA of the cell is simply the surface area of the cell times the
cell's suitability and can range from zero to the full value of the cell area.
Therefore,the cell's WUA is the output of a model incorporating three vari-
ables,their respective probability functions,and area.As was mentioned
previously,the WUA response to mainstem discharge for a modeled site is
obtained by repeating the above process for each cell in the site over a range
of flows.
The primary reason for the stratification of specific areas into representa-
tive groups and subgroups was to provide the similarity information necessary
for extrapolation.Implementation of the extrapolation methodology produced·
WUA curves for 172 specific areas,of which 20 were modeled using RJHAB and
PHABSIM.RJHAB is the Resident Juvenile Habitat model developed by ADF&G and
PHABISM is the Physical Habitat Simulation System developed by U.S.Fish and
Wildlife Service1s Instream Flow and Aquatic Systems Group.The summation of
the WUA curves within each representative group yielded the Representative
Group WUA curve.
At this point,it is reasonable to ask what ~/e have on a systemwide level.We
have 172 individual pieces of the middle Susitna River which covers over 95
percent of the wetted surface area outside the mainstem.For each site,we
have a quantified response of three variables to mainstem discharge,modified
11-19
I~
-
I'I..
by fish preference factors from sUitability c:riteria.Cell WUA curves within
a site were summed as they are contiguous.Because we assume the juveniles
have little difficulty moving from one cell to another it is logical to think
of the site as a whole and site WUA curves are appropriate.The ten represen-
tative groups give us a categorization scheme which used hydraulic similarity
as a key.Summing site WUA curves within representative groups is an attempt
to achieve a higher level of integration,that is,~system WUA response to
mainstem discharge.However,before discussing the results of the WUA
model i ng process we must fi rst identify other factors whi ch,although they
were not modeled,may also affect the abundance and distribution of salmon in
the middle Susitna River.
Non-Modeled Habitat Factors
Figure 11-8 illustrates other factors,not modeled in the WUA representative
group functions,that may influence the rearing of juvenile chinook salmon in
the middl e Susitna River.Each wi 11 be outl ined in turn.
Temperature
Water temperature affects juvenile fish metabolism,growth,food capture,
swimming performance and di sease resi stance (AEIDC 1984).Below 4°C juvenile
fish tend to be less active and rest in sec:luded,covered habitats (Chapman
and Bjornn 1969).Brett (1952)reported that the preferred temperature range
for juvenile chinook is 7.3 to 14.6°C and noted that chinook under yearlings
displayed increasing percentage weight gains as temperature increased from
10.0°to 15.rC.
As outlined in the introduction,mainstem water temperatures normally range
from O°C duri ng the peri od November to Apri 1 up to 11 or 12°C from 1ate June
to mid-July.Maximum recorded temperatures at Gold Creek is 15°C.On the
other hand,clear water habitats such as unbreached side sloughs and tribu-
taries may be colder in the summer than the turbid water habitats of mainstem
and side channels.The colder unbreached tr'ibutaries and side sloughs may be
below JOC during the surruner,the lower end of the optimum range for chinook
II-20
1 -~-l j j -J ))1 1 J j ]1 j J )J
FLOW REGIME
PREDATION
*Variables modeled in WUA curvn
SPACE
REQUIREMENTS
INTERSPECIFIC.
INTRASPECIFIC
COMPETITION
VELOCITY *
REARING
,JUVENILE CHINOOK
SALMON
DRIFT
FOOD
AVAILABILITY
COVER *
WATER DEPTH*
............
I
N
I-'
Figure II-B.Factors that potentially influence rearing juvenile chinook.
-
,....
-
.-
-
-
(Brett 1952).In addition,slough temperatures show a marked diurnal varia-
tion.During the summer of 1981,diurnal temperature fluctuations in Slough
21 ranged from 4.5 to 8.5°C.However,juvenile chinook of Susitna stock may
be better adapted genetically to sustained growth at lower temperatures than
fi sh from ri vers in Oregon and Washi ngton where much of the temperature
preference information originates.Although Dugan et al.(1984)conclude that
water temperature is not a significant factor in affecting chinook dis-
tribution during the open water season,more juvenile chinook are found in the
.turbid waters of the side channels during July and August than in clear water
habitats.It is possible that they are more attracted to the warmer
temperatures of side channels than they are!to clearwater habitats.Water
temperature does appear to be a factor in the fall redistribution of some
chinook "into sloughs (see section on overwintering).
Water temperature may stimulate smolt outmi~lration (Sano 1966).and juvenile
chinook have been observed to cease outmigrating when temperatures fall below
7°C (Cederholm and Scarlet 1982,Bustard and Narver 1975).Outmigration of
chinook smolts begins in early May from the middle Susitna River when tempera-
tures can range from just above freezing to 7°C (University of Alaska 1984).
Food Availability
Fish food production and availability is probably the most important of the
biotic factors affecting juvenile chinook rearing and distribution in the
middle Susitna River.Becker (1970),Loftus and Lennon (1977),Gray and Page
(1980)and Burger et al.(1981)report that juvenile chinook feed predomi-
nantly on chironomids,available principally through the drift.During~August
and September,1982,ADF&G i nvesti gated food habits of juvenil e chi nook at
five side slough and two clear-water tributaries of the middle Susitna River
(ADF&G 1983a).At all sites,chironomids were numerically most important with
a variable ratio of larvae to adults.A food availability study was under-
taken duri ng June to September of 1984 by ADF&G at four study si tes -Slough
9,Side Channel 10,Upper Side Channel 11,and Side Slough 21.Chironomids
were again shown to be the principal food organism followed by ephemeropterans
and plecopterans.Drift at study sites increased significantly when the sites
breached.Chi ronomids formed over 50 percent of the drifti ng invertebrates.
11-22
-
-
.....
-
-
However,the study did not identify the source of the drift in the mainstem
enteri ng these side channels and side sloughs.Terrestrial insects usually
enter the drift by falling or being blown off riparian vegetation or washed in
from side channel areas inundated by rapid flow fluctuations (Mundie 1969;
Fisher and LaVoy 1972).However,terrestrial insects numerically averaged
less than 15 percent of the total stomach contents in the 1982 study (ADF&G
1983a).The relatively low importance of terrestrial insects in the diet of
juvenile chinook in the middle Susitna River is probably related to low
numbers in the drift,as the mainstem,side channels and side sloughs,in most
instances,lack a close border or riparian vegetation.Finally,juvenile
chinook have been observed entering the clearwater sloughs in the fall to feed
on salmon eggs and salmon carcasses.
However,an important factor in the abundance and distribution of aquatic
insects is the availability of invertebrate food items (Cummins 1975,Egg1shaw
1969,Hynes 1970).Van Nieuhenhyse (1985)demonstrated the association of
chironomid larvae with filamentous algae in a side channel of the middle
Susitna River and hypothesized that fish food production is based primarily on
benthic algae production.Although the filiimentous algae may not be a food
source directly,the microfauna and flora they support are.Algal filaments
are also important to chironomids in provid"ing support and protection from the
current and abrasive sediments.-Milner (198:3)reported a similar association
of filamentous algae and chironomids in turbid glacial meltwater streams of
southeast Alaska.Consequently,factors that affect primary production;
notably,bed 10a.d transport rate and the degree of 1ight penetration;exert an
influence on fish food production.Sediment deposition on the streambed may
bury sites suitable for algal colonization and reduce the ability of fila-
mentous forms to obtain firm attachment.A,n analysis of the photosyntheti-
cally available light under different dischCllrge and turbidity regimes in the
middle Susitna River has been presented by Re!ub et a1.(1985).
On the one hand,increased production of b,enthic insects will result in an
increase in drift.On the other hand,drift at a particular site is also
greatly enhanced when the site is breached by mainstem flow.Juvenile chinook
typically locate drifting food items by sight (Mundie 1974).The ability of
fish to detect food items is reduced in the turbid water of the side channels
11-23
-
-
....
-
and breached side sloughs and may explain the preference that juvenile chinook
have for shallower depths and lower velocities in these waters,as reflected
by the suitability criteria.This preference would enhance feeding on the
drift at these sites.
Predation
Predation can cause significant mortalities cimong rearing juveniles,particu-
larly after emergence from the gravel (Allen 1969).Cover is extremely
important for the ability of rearing fish to avoid predation.Fish predators
of juvenile chinook in the middle Susitna River include rainbow trout,rearing
coho,resident dolly varden,burbot and sculpins.Mortality from fish pre-
dation is probably reduced for juvenile chinook that migrate to the side
channels and obtain cover from the turbid walter.In clearwater habitats the
juvenile fish may also be taken by piscivorous birds,notably kingfishes,
dippers and mergansers.Stratton (1985)reports on predation during the
winter and concludes that although ice and snow replace turbidity as a source
of cover from birds,juvenile chinook are still vulnerable to these predators
through open leads.Dippers were observed c:apturing juvenile fish at almost
all open water areas of the middle Susitna River.Stratton also believes that
scul pi n predati on coul d be an important factor i nfl uenci ng winter survival
rates of juvenile salmon.'Overall,the amount of predation on juvenile
chinook in the middle Susitna River is not well-defined.
Space Requirements
Territorial behavior and intra-and interspecies competition for food influ-
ence the space requirements of fish,which valry according to the size and life
stage of the fish and the time of year.Studies in California by Burns (l971)
showed significant correlations between living space requirements and resul-
tant salmonid biomass.In the natal tributaries Indian River and Portage
Creek,territorial behavior and competition with other chinook and emergent
coho may account for the downstream migration of significant numbers of
juvenile chinook from the tributaries.Juvenile chinook densities in the side
channels and side sloughs do not appear high enough for space requirements to
be an influential factor in the determination of habitat quality.
II-24
Overwintering Survival
Overwintering survival is a significant factor in the production of juvenile
rearing sa1monids and is certainly an important factor influencing juvenile
chinook in the middle Susitna River.The overwintering period,as defined by
the IFRR Vol.1 (EWT&A and Entrix 1985),is from September 15 to May 20 and
includes the fall transition period beforE!ice formation.The juvenile
chinook which remain within the middle Susitna River overwinter predominantly
in tributary,tributary mouth and slough type habitats (APA 1985).Stratton
(1985)identifies two groups:
(a)
~
(b)
~
Fish which remain an entire year within their natal tributaries before
beginning their smo1ting migration
Fish which leave their natal tributaries and overwinter in slough,and to
a lesser extent side channel,habitats in the middle Susitna River.
.....
-
Little overwintering takes place in the mainstem Susitna (ADF&G 1983a, 1983c,
Stratton 1985).
Juvenil e chi nook are attracted to the side sloughs duri ng September and
October by the warmer temperatures resu1tin~~from groundwater upwell ing and
possibly by the.presence of salmon eggs laic!by spawning fish (Dugan et a1.
1984).In these habitats juvenile chinook no longer obtain cover from turbid
water and,hence,object cover probably becomes more si gnifi cant.Burger et
a1.(1983)observed that below Goe juvenile chinook in the Kenai River moved
closer to substrate cover.Bjornn (1971)also considers substrate to be
essential for winter cover.Ice and snow may act as a source of cover but the
warmer water associated with upwelling frequently creates open leads during
the winter.
Although there appeared to be a significant number of benthic aquatic insects
at the sites examined by Stratton (1985),drift of food organisms is reduced
at the lower winter flows (Richards and Milner 1985)and feeding activity is
probably low.Stratton found that juvenil e chi nook stomachs occasi ona lly
examined throughout the winter always contained aquatic insects but chinook
II-25
,.....
J
I
-
growth is minimal,as discussed earlier.Juvenile chinook become less active
at low water temperatures and feeding is probably related to maintenance of
body functions.Therefore,food availability is probably not a relatively
significant factor during the winter months.
Stratton (1985)found that predati on,part i c:ul arly from scul pi ns duri ng the
winter played a significant role in overwintering mortality.Predation by
dippers in open leads was also observed.
Ice processes dominate the hydrological and biological characteristics of the
middle Susitna River from November to Aplril and significantly influence
overwintering survival.The formation and characteristics of the ice are
summarized by R&M (1985)and EWT&A and Entrix (1985).The leading edge of the
ice cover usually arrives at the confluence of the Susitnaand Chulitna Rivers
during November or early December and reaches Gold Creek by late December or
early January.A potential problem for over'Wintering fish in sloughs occurs
because of staging,a result of anchor ice formation,ice damming or snow
loading.The relatively wann water in the sloughs is replaced by large
volumes of DOC water and slush ice.If the condition persists the wanning
influence of the upwelling is diminished and the fish are probably displaced
and move downstream (Stratton 1985).Anchor ice may encase the substrate,
making it useless as cover tq:;fi'$h.Side channels and side sloughs without
significant upwell ing may deJ;t:~r;;;:alt~,Jreeze compl etely kill ing any rearing
fi sh unable to escape....".","".."
Another potential problem to overwintering juvenile chinook caused by ice
processes occurs duri ng spri ng break-up.Break-up ice jams commonly cause
rapid,local increases in stage that flood side channels and side sloughs,or
that divert ice into them eroding away sections of the streambank.The final
destruction of the ice cover occurs in early to mid-May when a series of ice
jams break in succession,adding their mass and momentum to the next jam
downstream.This continues until the rive!"is swept clear of ice.Algal
growth,benthic macroinvertebrates and 1+chinook may become displaced during
these events.However Stratton (1985)concl uded from the ADF&G wi nter study
that there is a downstream movement of a significant number of chinook from
the tributaries and side sloughs of the uppE~r sections of the middle Susitna
River before break-up occurs.
II-26
-
i~
-
"""
I"'"
i
I
-,
WUA Response Curves for Represl~ntative Groups I-IX
The juvenile chinook WUA responses to mainstem discharge at Gold Creek for
representative groups I-IX are represented in Figures 11-9 and 11-10.
Representative Group X has been omitted because the specific areas modeled in
this group do not represent the entire population of specific areas in Group X
and because the composite WUA curve is relatively insensitive to changes in
mainstem discharge (Steward et al.1985).
The response of wetted surface area (WSA)to mainstem discharge and the
combined (aggregate)response of WUA for alll 172 specific areas is shown in
Figure 9.Although the change in WSA,is quite pronounced (ca.1150 acres)
over the range of mainstem discharges indic:ated,a response in WUA is not
apparent.In part,this is attributable to the scale at which the response
function is plotted.However,it is also attributable to the interaction
between streamflow and the rather compl ex c:hannel morphology of the middl e
Susitna River.Because of the irregularity of streambeds and streambanks in
peripheral habitats,approximately the same amount of low velocity rearing
habitat exists over a broad range of streamflows.As streamflow varies,the
location rather than the amount of rearing habitat responds.Similar
observations have been reported by other investigators evaluating rearing
conditions within a river system (see,for example,Wilson et al.1981).
The response of rearing habitat by location can be inferred from the WUA
response functions provided in Figure 11-10.Although the aggregate response
function shows little change to receding str"eamflows,WUA response functions
for individual representative groups indicate some habitat types undergo
substantial change.Most notable are the response functions for
Representative Groups II,III,IV and VI,each of which shows maximum WUA
values at different mainstem discharges.A second point is that at 25,000
cfs,each of these representative groups posSiess approximately the same amount
of WUA.However,at 10,000 cfs Group IV dominates.Thus,as streamflows
decrease so does habitat diversity,even though approximately the same amount
of habitat exists in the middle Susitna River.
-A
100
-90
~~NSA"-80
I'""'0-
Ul 70
....-
0 60
Ul 50c
0
.~......40......-.~
E 30
20 ~t\'~,,,.)-,~,....<t:
lLJa:10«HUA
~0
0 -tOOO 8000 12000 16000 20000 2401)0 28000 32000 36000 40000
MAINSTEM DISCHARGE (c fs)
-
-
Figure II-9 Comparison of total wetted surface area (WSA)and weighted usable
area (WUA)in the middle Susitna River as functions of mainstem
discharge.
II~28
B
7.00
~~,~
6.30
~5.60 ~TDTAL"4-
cr 4.90en
"4-4.20......a
(I)3.50c IVa-.....-.-1 2.80r--i
'""r--i
•.-1 2.10 '-E --r-1.40
<:
~.703:
""'"0.00
0 4000 BOOO 12000 16000 20000 j~4000 28000 32000 36000 40000
~'
MAINSTEM DISCHARGE (efs)
Figure II-IO.
+
Aggregate and individual group responses of ~UA for juvenile chinook
to mains tern di scharge for Reproesentative Groups I-IX (form Steward
et a1.1985).
II-29
-
-
The significance of this change is not defined.Assuming temperature,food
avail abil ity,predation and other factors welre simil ar in all representative
groups,a decrease in streamflow would have little consequence on the overall
amount and quality of WUA,even though significant changes could occur in any
one representati ve group.If,on.the othl2r hand,food avail abil ity and
biologic factors were better in Group IV,then substantial improvement in
rearing conditions not reflected in the aggregate WUA curve would result at
lower streamflows.If stream temperaturl~s or food availability were
unsuitable in representative group IV,then a·negative effect not reflected in
the aggregate WUA curve would result.
Individually,Group IV possesses the largest WUA values,particularly at lower
flows.This is because Group rv includes specific areas which are side
channels that breach at low discharges.At these discharges relatively large
amounts of wetted surface area exist in comparison to specific areas from
other representative groups.Generally,the WUA response curves indicate that
the amount of rearing habitat available at a particular specific area is
strongly influenced by the mainstem discharge at which its upstream berm is
overtopped.Under non-breached conditions,juvenile chinook habitat typically
is relatively small.When a site breaches,the availability of rearing
habitat increases significantly because of the influx of turbid water and the
increase in wetted surface area.For example,the peak amounts of WUA in
Groups II and III at high and intermediate flows,respectively,are a result
of breaching.The other groups,which all have very high breaching flows,
have relatively low amounts of WUA and are relatively unresponsive to normal
changes in mainstem discharge.The responses of WUA for each specific area in
the representative groups has been discuSSl2d at length by Steward et al.
(1985)•
Interpretation of Response Curves
The question arises:Do the weighted usable area forecasts for juvenile
chinook in each representative group,based on depth,velocity and cover
criteria,accurately represent the system-w"ide response of juvenile chinook
habitat to varying discharges in the middle Susitna River?One method for
answering this question is to ascertain if the abundance and distribution of
II-30
-
.-
.....
-I
!
juvenile chinook is reflected by the weightE!d usable area forecasts for the
representative groups.If this ts shown to be the case then other potentially
significant factors which were not modeled are adequately incorporated in the
forecasts either through them having a relatively small effect or they are
correlated with the factors selected for suitiabil ity criteria development.If
there is a disparity between the relative distribution and abundance of
juvenile chinook in representative groups and the weighted usable area fore-
casts for those groups then the aggregation of the response curves will not
provide.an accurate forecast for the entire middle Susitna River system.
Modification may then be required at one of two levels •
(1)The site model level -to inCOrpl)rate the additional significant
variables •
(2)The representative group level -use factors to weight curves to
reflect abundance and distribution information.
The modification of weighted usable area curves based on fish utilization
patterns has been employed.in other IFIM studies (Crumley &Stober 1984,
Wilson et al.1981)~
Correlation with Juvenile Chinook Distribution Data
A fi rst step in the approach was to ascertain if the abundance and di s-
tribution data collected for juvenile chinook during the ADF&G·resident and
juvenile anadromous fish studies program werle adequate to provide comparative
information between representative groups.An ADF&G report summarizing salmon
fishery data for selected middle Susitna River sites (Hoffman 1985)were used
as the principal source of information.The data was examined to see if the
following patterns could be ascertained on a representative group basis.
(a)Seasonal variations -both on a month'!y and a yearly basis from 1981
through 1984.
11-31
~-
-
-
-
(b)Geograp~ical variations -to determine if a greater abundance of juvenile
chinook occurs in certain sections of the middle Susitna River (e.g.
closer to the chinook natal tributaries).
After examination it was apparent that there was insufficient information to
examine variations on a yearly basis.Therefore,the years 1981 through 1984
were pooled.Of the 172 specific areas,52 had abundance data for at least
one month over the four years,yet only 20 of these areas had more than 3
separate months from June to October.Winter abundance information was
availa~le for 20 specific areas.Another problem with the abundance data is
that different sampling methods were used to collect fish depending on the
site or information source,namely electroshocking,beach seine or minnow
traps.The counts were either presented as catch per unit effort (CPUE)
defined as number of fish per 300 square foot cell (6 1 x 50')at a specific
area or as counts per sampl ing station at a specific area.Unfortunately.
neither set of data was sufficient to provide an adequate comparison between
representative groups either seasonally or geographically.
Consequently,to approximate comparative abundance trends of juvenile chinook
between representative groups,a relative abundance factor was introduced in
an attempt to combine the CPUE and count data.This factor,using a scale of
o to 10 is outlined in Table II-6.Each specific area with data for a
particular month was scored with the relative abundance factor and then the
factors were averaged on a representative group basis.This was possible for
four representative groups -Groups I.II.III and IV which are the most
important in terms of WUA.
The relative abundance factors are summarized in Tables II-7 and 11-8 for the
months June through October.Unfortunately:.there are insufficient data to
produce relative abundance factors for June"July or August in Group IV.To
ascertain if the WUA forecast reflects the distribution of juvenile chinook
for these particular months.the WUA values for the typical average flow at
Gold Creek for that month were determined fr"om Figure 11-7 and are presented
in Table 11-9.
11-32
.....
-CPUE
TABLE 11-6
RELATIVE
ABUNDANCE
FACTOR NUMBER
No fish 0 No fi sh
0.5 1 7
0.5 -1.0 2 8 -14
~1.0 -1.5 3 15 -22)
1.5 -2.0 4 23 -30
~2.0 -2.5 5 31 -38
2.5 -3.0 6 39 -46
3.0 -3.5 7 47 -54
~3.5 -4.0 8 55 -62
4.0 -4.5 9 63 -70
4.5 10 70
-
11-33
4I!ilj.
Table II-7.Relative Abundance Factors for specific areas in Groups I and
II for June to October.
-
TABLE 1
i"""GROUP I JUNE JULY AUWST SEPTEMBER OCTOBER
Specific Area$<:p UE NOS.CPUE NOS.CPUE NOS.CPUE NOS.CPUE NOS.
107.6L 0 2 4.5 4.5
135.6R 0.,025 0 0.86 1.13
112.5L 0.30 35 0.56 21 0.08 14 1.94 10
I"""
IOS.2R P
121.9R P
139.9R 0 0.3 0.9
133.9L Q 0.25 6.6
136.9R 3.2
''oN'''''''·
t "_••..-,,,...."·,ON"·'·-··,---,····,,~:;~-;~-~~~~O ~,·,·_"_·<".c,~~<.__._~'......·~,."._~........_;a-...~\
"Mean 11.5 0.41 9.25 2.64 6.12
/,.-..•."...."
Relative Abundance ...f·/
factor (RAf)1.40 1.16 1.40 3.44
J:-.-
CROUP II JUNE JULY AUGUST SEPTEMBER OCTOBER
Sped fi c Area$Cf'UE NOS.CPUE NOS.CPUE NOS.CPUE NOS.CPUE HOS.
tv "'\101.4L Y-o.sf 6 0.2 0.47 1.4
S\(115.6R 0.3
Q ~.143.4L
\~I'('"\\5/~'~113.7R 0 0 0 0.25 0.95 8.S 0.42 36_.
\122.SR
(\\.
;..123.6R (-0.1'j
140.2R ()0 7 0.15 33.5 0.77 4.0
126.OR /'0.08-0.10 1.0 0.60 0.40
144.4L 5 75 60 40
"7.9L
137.SL .05 0 0.05 0
142.1 R a 27 32 32:~>
133.9R P-Mean 0.14 )l<S 0.14 18 0.49 39 1.08 34
"Q""
Relative Abundance --/~~
/factor (RAf)(0.67 1.7 2.9 3.S
11-34
Table 11-8.Relative Abundance Factors for specific areas in Groups III
and IV for June to October.
CROUP III JUNE JULY AUCUST S£PTEt16ER OCTOBER
Specific Area.CPUE NOS.CPUE NOS.(f'UE NOS.CPUE NOS.CPUE NOS.
101.2R 8 2
101.6l 19
110.4l 23 30.5 27 7
115.OR 0 22 0.05 10 0.15 21.5 0.45 21
119.3l P
nO.2R p
128.8R 0.25 2 0.025 51 1.05 44 0.15 36
133.7R
~132.6l 0\2 260 30
l00.o\R 0
137.2R 0
..-
10\1.4R 20 0
128.5R 10 5 P 3
.~
Mean 31.5 73 0.3 14.2
Relatiye Abundance
Factor (RAF)3.3 3.8 2.0 1.20
--1 1 }J 1 1 J )))1 1 j 1 1
Table II-g.C.rnJliri sen .f ~e htive Aluniince Ficttrs ind WUA forecasts
for Groups I,II,III and IV for June to October.
WUA
50673
239041
60333
3152001
5,000
OCTOBER
1.20
//'---"'~\
,r<50~i
(3.0)
(3.5)
Relative
Abundance
Factor
i
I
\
\
'-
I
wu4
i
692io
I
3689f6
111787~3
19433~9
\
13,300
SEPTEt1BER
Relative
Abundance
Factor
r~'
WUA
72042 3.0
695729 3.5
1164413 2.0
1319442 .
AUCUST
22)000
Relative
Abundance
FactorWUA
JULY
24)300
;>
Relative,
Abundance
FactorWUA
JUNE
27)500
1
1.25 68733 I 7028'1.22
'::::::I c~~;~\:::
11 53321 I \.1 246-5 70~-"'"
____~___'~""".__1.~~\.-1.'
MONTH
IV
II
III
Average
flow (cfs)
Repre-
sentative
Croup
...........
I
W
0"1
-
.-
-
-
.-
To examine geographical (longitudinal)variations,relative abundance factors
were determined for Groups I,II,III and IV combined for the following
sections of the middle Susitna River during the months of August and
September.
1.Chu 1i tna/Sus i tna confl uence (RM 98.!»to Lane Creek (RM 114.0).
2.Lane Creek (RM 114.0)to 4th of July (RM 131.0).
3.4th of July (RM 131.0)to Fat Canoe Island (RM 147.0)
The comparative WUA forecasts for these sec:ti ons for Representative Groups
I-IX are given in Figure 11-11 through 11-13.
The least amount of WUA occurs downstream from RM 114 (Fig.11-11).The WUA
in this subreach is concentrated in Representative Groups III,VI,and IX.
WUA is relatively constant in all representative groups until streamflow drops
below 12,500 cfs.At mainstem discharges below 12,500 cfs nearly all rearing
habitat within this subreach is found in lar~le side channels.The importance
of this habitat,as represented by WUA,incy'eases markedly in Representative
Group IV but declines "in all other groups at low streamflows.
The greatest'amount of WUA occurs in the multiple channel subreach from RM 114
to 131 (Fig.11-12).WUA is well distributed among all representative groups
and a relatively high habitat diversity occurs around 20,000 cfs.Diversity
gradually decl ines as mainstem di scharge decreases.Below 12,500 cfs nearly
all WUA is associated with Representative Group IV.
Above RM 131 the same trends in habitat diversity exist (Fig.II-13)as in the
middle subreach.However,high diversity persists over a broader range of
flows.Representative group IV contributes to the majority of WUA at flows
below 12,500.
The principal conclusion from this analysis is that the WUA forecasts for
Representative groups I through IV seem to adequately predict juvenile chinook
habitat for the months June,July and August.It is reasonable to assume that
II-37
0
~
C>I.t)0
C>.
0 CO...m
::E:
~
C>
C>~ato 0,..,
l+-
X.......-......-0
0
1
~to>-.-
(II'
~
0 ~0
0 0liS~
~-~en->0 ~or-
8 ~....toN~
UJ r:::
t!)~er II',.&<I:~/::c ~...U...~,N en ~.I ......~Cl.::E I+-
0 UJ 0
~0 I-0~en V)z:~......II'
<I:r:::
:::E 0
8 ~...V)
N ~-~o
<v=>-
C>3-
0:i:
0
0
0..............
I
t-+,-.....
0 Q)
s...
:::;)
0 g 0 0 2 0 0 0 ...~0 en
0 ~"":~'"!~"":0
N ..;..;0 u..
(°U °bs to SUOHnW )'tOM
-
II-38
--------------~,----------.,.--
1 J OJ ]J 1 1 ]1 1 1
I I I I I .I __~_~o I
8000 12000 16000 20000 24000 28000 32000 40000
I.
36000
---...--......2
/-----.1
t
/J \\
\
\
"'-\
'\
"'-'"'"---
/
I'--~~
J'•..--.--.-./.........-/../'.,.....-"0......._ _'.--........._J-......._---~·3____/./-.8
r-'"7r -,-,0::.:'-'_.__'--',-'---1-~.~__'-'-'/.'-'~_.-9,--~.....-..,/__-I _:::---,......."-.5~-_.."---_.~__-..1,II
2.00
1.80 -
1.60 -
.1.40 -
4J-.cr
ttl 1.20 -1-0
lfl 1.00 -1c:
0
'M......rl
......rl .80 -I 'M
W e
1.0
«.60 -i
•40 -
.20 -
0.00 1 I
0 4000
MAINSTEM DISCHARGE (efs)
F;gure II -12 .WUA.responses of Representative Groups I -IX for RM 114.0 to
131.0.
])l j J 1 1 -~i J )j J 1 )J )-,
2.00
1.80
1.60
-•1."0
+J.....
l I
..........
i
~o
.
t7
II)1.20 ~
"-
C
~LOO -I
c:l
•.-4
r-t
;,:::.80e
«.60:::;)
X
.~O
.20
0.00
I
0 ,(000 BOOO 12000 16000 20000 24000 28000
6
32000 36000 ,(0000
Figure 11-13.
MAINSTEM DISCHARGE (efs)
WUA responses of Representative Groups I -IX for RM 131.0 to
147.0
representative groups are also adequate for these months.There-
do not require modification before aggregation into a system-wide
the other
fore,they
response.
"i,
II
i'
lif(
I
fj
\
\
\
iI However,the implications of the trends evident in Figures II-II through 11-13
l\are~not yet well understood.,large.!:~~~~r:?_~.oL-.J,lPl.e,nile..",c,htn92~,,_.~,~~~:_,._~,::.n__.
\SjlPtUJ:e~L,~J~.Q~~~,~~"13.~.,~~,~,~.J~,€!IQw""w'Very'"'few""OOfJ<tur,.e,s ",have,-,(}G,Gu.~~ecLJt~L9w _~.
'"..114l •.,,..~h ~ssuggests ",t~~:.~h~.aggre~at~resgQDse"."cur,:,v,es.~~.",.ar,e.",~_J:e,as'Quab.1e.fndfc'at~'~'s""~:f""'~~Tl'i~~~i o'n 6y"j uve'n 11 e"f'fsh':and'-~f,..,t h,!L,,,teJ.a,t~v.e.~,_imp.Q.r.t91)£~_.ot,_
i ncrj~V]Jj~Y~ir'-s'~b;~'~·~~~~,:",toc.,,,,pea,r;:,;i~'~"~~'~H'owev'er';'''''tfi'e'-'~~n s eq uen ce s of s hi ft ing a
j!J','Il""··'~;~"''''''~·".4'\':!'II!~,~'''~'.;!!):ii!(tlS'''''~''·>
relatively even distribution of WUA between five or six representative groups
under natural flows to one dominated by Group IV at streamflows below 12,500
cfs may depend upon the importance of non-modeled factors.It is logical to
assume that habitat diversity,as modeled,is high,a greater range of
non-modeled habitat qualities is available.This may not be true as diversity
decreases and proportionately more WUA is found at only one or a few sites •
For example:,food availability,a non-modeled factor,may be extremely
important in the summer months.Under with-project conditions,when
stt"eamflows are reduced and Representative Group IV is contributing
proportionatlely larger amounts of WUA to the total available,it may be that
system-wide habitat availability and quality is either reduced or enhanced
depending upon the availability of food at sites within Group IV.
,-
-
-
......
-
-
Aggregation of Curves for System-Wide Response
,....
-
ThE~composite WUA for Groups I through IX was given in Figure 11-10.The use
of the repre~sentative group curves without modification implies that factors
such as temp1erature and food availability are not significant when compared to
the cri teri ill used.However,these may be otherwi se accounted for in the
modeling process because the cover criteria for juvenile chinook,which
weights turbid water as being more suitable habitat,implicitly includes a
food availability or temperature preference component.The rationale is that
the introduction of turbid water into a clearwater channel increases the
amount of drifting food organisms and the turbid mainstem water is warmer than
thl:!clearwater.The aggregate response for June,July and August can probably
~~~.~~..~~tfPJ C-t/'Vlt ~~4 c;J,.~#,"~,
"\ I -4~~wi:IfI....~.',.~..,--~~~.I~
I~
.....
r .
~
be extended to apply to the open water season of May 15 to September 15
identified in the IFRR Volume I.
However t the aggregate WUA response curve for May 15 to September 15 is not
applicable to the fall transition period from the middle of September to the
end of October as indicted by the juvenile chinook abundance and distribution
information given in Table II-10.The relative abundance factors for Rep
Groups I and II during this time period were significantly higher than Rep
Groups III and IV.However the WUA forecasts are higher for Group III an IV
in September'and Group IV in October.In addition t the geographical dis-
tr-ibution of the'fish during this time period is not addressed by the WUA
forecasts.A significantly greater number of juvenile chlnook are found at
sites above 4th of July Creek than below it.The middle section of the river
from Lane Cr'eek (RM 114.0)to 4th of July Creek (RM 131.0)has a high WUA of
1 t 972 t OOO ft 2 in September and a relative abundance factor of 1.50 t but above
4tlh of July Creek the factor increases to 4.73 while the WUA forecast is only
1t 058 t OOO ft 2 •
ClearlYtonEl or more factors that significantly influence juvenile chinook
habitat during this time period are not included in the suitability criteria.
Thi s trans i ti on peri od is when juvenil e ch i nook not overwi nteri ng "j n
tributaries seek out suitable overwintering sites in mainstem associated
habitats.Some chinook leave the tributaries at this time and thus t suitable
areas in close proximi ty to Portage Creek and Indi an River are favored to a
greater extent.The movement of juvenile chinook from turbid water areas into
sloughs (Representative Groups I and II)during this period is probably
related to the warmer water temperatures that are associated with groundwater
upwelling in the sloughs (Dugan et al.1984).Upwelling in side sloughs may
result in open leads throughout the winter thereby contributing to more
favorable overwintering habitat.The areas with the highest degree of
upwelling,as indicated by the chum spawning analyses t occur above 4th of July
Creek.Unlike the summer months t the turbid water in September and October is
not warmer than the clearwater and thus a temperature preference at this time
is not accoLlnted for by the cover criteria of turbid water.Juvenile chinook
may also be attracted to upwelling areas in side sloughs to feed on chum
salmon eggs and carcasses.
II-42
Tab 1e II-IO.Comparison of Relative Abundance Factors and WUA forecasts
for Groups L II,I II and IV combi ned duri n9 August and
September for different sections of the river.
,....
-
-
MONTH AUGUST SEPTEMBER
Average flow (cfs)22.000 13.300
Relative Relative
Croups J,II,I I I •
Abundance Abundance
and IV cOlllbined Factor WUA Factor WUA
RH 98.5 to filM 114.0 1.78 429466 1.90 522890
RH 114.0 to ~~131.0 3.72 1869149 1.50 1972252
RH 131.0 tOI 147.0 3.0 943181 4.73 1057891
II-43
-Consequently,to obtain an aggregate system response of WUA for juveni 1e
chinook that is applicable to the fall transition period the representative-group curves require inclusion of temperature and possibly food preference
factors at this time..
Fall Transition Modifications
-
-
-
-
-
-
.....
It is suggested that the open-water curves be modified so that they are
applicable to the fall transition period by first weighting them geographi-
cally,thereby giving greater emphasis to WUA above 4th of July Creek (RM
131.0).The curves would then be adjusted to incorporate temperature prefer-
ence.A flow diagram for this approach is given in Figure II-14.
Applicability of Existing WUA Forecast for Overwintering Assessments
Two fundamental problems make the application of the open water or fall
transition WUA response curves inappropriate for use under winter conditions
to predict juvenile chinook habitat availability.
First,one assumption in the modeling is that instream hydraulic conditions,
to a large degree,influence habitat conditions for rearing fish.Open
channel hydraulic theories are applied to define relationships between
discharge,r'jver channel geometry,flow velocity and water surface elevations.
The presence of river ice,however,negates the hydraulic models calibrated
for summer flow conditions and makes them inappropriate for predicting
reliable depths and velocities associated with winter flow conditions.
The second problem is related to the significant difference between the
behavior of the juvenile chinook according to the time of the year.During
the summer,as the juvenile fish are actively feeding and moving about in the
water column,flow velocity has a significant influence on habitat suit-
ability.As discussed earlier,in the winter feeding by fish becomes reduced
at the lower temperatures (particularly below 4°C)and the juvenile fish move
closer to the substrate.Consequently,the velocity suitability criteria
developed for open water conditions are not applicable.Therefore,existing
WUA forecasts for Representative Groups I through IX are not consi dered
applicable when water temperatures are less than 4°C .
11-44
1 )J ,J 1 ]}-)
I-l
I-l
I.::::-
c.n
Seatonal BreachingCoverTemperature
Variations Flow
I ~1 RepreMntatlvt WUA System r"poflltStreamflow-Temperature conditioned ~Gr:a;by of juvenile chinookA.temperature hab/1at.
IEuphotiCfoodQualitative
Availability ~-----------Model assessment
t
PAR
Turbidity
,Figure II-14.Conceptual flow diagram of incorporation of temperatures intothemodel.
.....
-
-
Application of WUA Curves
The app1 ication of aggregate juveni 1e chinook habitat response curves to
mainstem discharge,as outlined,involves the assumption that conditions under
which they \l/ere modeled remain the same.If,however,factors not incorpo-
rated in thle model become significant under altered discharges in a with-
project condition then their application may not be appropriate.Although the
major project effect is to alter the flow regime,significant changes will
occur in temperature and ice processes and,also,in the period of the year in
whi ch they b,ecome important.
A method of ascertaining the applicability of a response curve for various
time periods is to construct preliminary subjective flow diagrams as
illustrated in Figure 11-15 which,in this example,compares natural
conditions \'jlith Case E-VI Stage II.As discussed earlier,the formation of
ice in the 1river precludes the use of the WUA response curves in the winter
from the middle of November to the middle of May.However,the period of time
over which ice will be a significant factor under Stage II conditions will be
reduced and,thus,use of the fall transition period curve may be extended.
As outlined in the introduction mainstem water temperatures will be colder in
the summer under Stage II conditions and may fall below those in the sloughs.
These temper'atures may be lower than the optimum range for chi nook and affect
growth as discussed by AEIDC (University of Alaska 1984).Consequently,
temperature may be a factor during the summer and,if desired,could be
incorporated in the open water model using the same technique as that employed
for the fan transition period response curve.However,the mainstem water
temperatures will be warmer during the fall transition period.Thus,the
difference in temperature that now occurs during September between side
sloughs with upwelling and mainstem-inf1uenced habitat and which causes
juvenile ch'inook to select side sloughs for overwintering will be delayed.
Therefore,iit may be more appropriate to extend the application of the open
water response curve before app 1yi ng that for the fall trans iti on peri od.By
considering the significant factors in this manner,the application of the WUA
response curves is more appropriate.After defining the use of the
appropriate response curves,habitat time series and habitat duration curves
can be constructed.
11-46
I "",__~'~.,~:,.,'..,-,.~.~"""'''U'-__~·''''".''''''·'';''';'''''''''~·'~,_.",."",",~~.,..,.,\".•.·"\'"',"'~,.'~'O"'~'·~·M''~'·~·,·.·_---,'-'''.•••~.-.~,,_.
J ]1 I J J ,)1 1 ,J
September --..May I June I July f Aug I Sept I Oct,Nov.Dec t Jqn •Feb I Mar.Apr I Mo~I
.....~...-------_...._------------..
~jiP ....---_.........•...
VELOCITY
--------------------------------~.~
~-----------
."------------
~.
TEMPERATURE
DEPTH
COVER
~~
~-
Chinook eggs and
emergent fry In natal
trlbutarles-not
~
Influenced by alterations ...•
in moinstem discho rge.
........-----------------...........I~
1
.......--.Important Concern
Possi bly Important
Not of Concer n
..II ..------••-...--...~......
........
....
:4 ..
FOOD
AVAILABILITY
SPACE
PREDATION
Natural
StaQ8 II with project
Variables model by suitability criteria.
......ICE
Fi gu re II -15.Comparison of habitat factors by time period under natural
and with-project stage II conditions.
....
,~
-
-
i~'
-
"""'
.'~s._._~.
Will be provided later.
III.RESPONSE OF CHUM SALMON
111-1
-
-
-
..-
IV OTHER SPECIES
Introduction
(will be provided later)
Table IV-l
(will be provided later)
IV-l
.....
....
I.....
....
,...
-
-
Sockeye Salmon
Adults
Susitna River sockeye salmon make a substantial contribution to the upper Cook
Inlet commerciial fishery.The average annual catch of Susitna River sockeye
in the fi sheJ'y (between 134,000 to 402,000 fi sh)over the past 31 years
(1954-1984)is;surpassed by only the pink salmon catch during even years and
the annual chum salmon catch (Barrett et al.1984,Jennings 1985).
There are two distinct runs of sockeye salmon in the Susitna River.The first
run does not spawn in the middle Susitna River but the second run usually
enters the middle Susitna River near the first of.August.Their migration
continues through late August (Barrett et al.1984,1985).The timing of the
sockeye mi grat i on appears to be re 1 at i ve 1y cons i stent from year to year.
Spawning activity usually occurs from mid August through mid September
(Barrett et al.1985).
The average annual sockeye salmon escapement to the mi ddl e Sus itna River was
estimated to be 6,300 fish at Talkeetna Station (RM 103)and 2,400 fish at
Curry Station (RM 120)(Table IV-2).These estimates were based on tagging
studies conducted in 1981-1984 (Barrett et al.1984,1985).Spawning ground
surveys conducted subsequently indicate that these escapements overestimate
the number of fish spawning in the middle Susitna River.ADF&G field studies
have indicated that a substantial portion of the escapement passing Talkeetna
Station later returns downstream to spawn in habitats other than those in the
middle Susitna River.
In 1981 to 1984,an estimated 52 to 83 percent of the sockeye escapement
passing Tal keE~tna Stat ion coul d not be accounted for on the spawning grounds
and may have returned downstream.The number of milling sockeye passing Curry
Station was less than at Talkeetna Station,as only 35 percent of the
escapement apparently left the middle Susitna River.The milling components
of the escapements are approximations as they were developed by comparing the
escapements at Talkeetna and Curry Stations with the estimated total slough
escapement of sockeye in the middle Susitna River.Since almost all sockeye
IV-2
----------~--------"-----------------------..,--
-J 1 i }1 -J J 1 1 )1 J 1 )
Table IV-2.Average salmon escapements in the Susitna River by species and location.
Location/
River Mile sockeyel Chum 2 Coho 2 Pink3 Chinook4 Total
Yentna station 126,750 21,200 19,600 odd 48,4,00 odd 215,950---RM 28,TRM 04 even 408,300 even 575',850
Sunshine Station 121,650 431,000 43,900 odd 45,000 88,200 odd 729,750
RM 80 even 730,100 even 1,414,850
Talkeetna station 6,300 54,600 5,700 odd 5,900 16,700 odd 89,200
RM 103 even 125,500 even 208,800
1-1 Curry station 2,400 28,200 1,600 odd 3,300 13,000 odd 48,500
<RM 120 even 87,900 even 133,100
Iw
M~nimu~Susitna 248,400 452,200 63,400 odd 93,400 odd 857,500
even 1,138,400 ---R1ver even 1,902,500
-~~~-'--_.-----_..-
1 Second-run sockeye escapements.Four-year average of 1981,1982,1983 and 1984
escapements.
2 Four-year average of 1981, 1982,1983 and 1984 escapements.
3 Odd is average of 1981 and 1983 escapements.Even is average of 1982 and 1984
escapements.
4 Three-year average of 1982,1983 and 1984 escapements.
5 Summation of Yentna station and Sunshine station average escapements.Does not include
escapement to the Susitna River and its tributaries below RM 80 (excluding the Yentna
River)•
Source:Barrett et ala 1984,1985
.......
-
-
-
-
-
-
spawn in slouglhs in the middle Susitna River,the total slough escapement is
an estimate of the spawning population of sockeye within the middle Susitna
River.The difference between the total slough escapement and the escapement
at a fishwheel station has been attributed to fish that move into the middle
Susitna River and 1ater return downstream to spawn el sewhere (i.e.mi 11 ing
fish).The milling component also includes any sampling error introduced from
escapement surveys or popul at i on est i mates at the fi shwhee 1 stations and
within the sloughs.
Escapement of sockeye salmon to the middle Susitna River was estimated using
the total slough escapement since almost all sockeye salmon spawn in slough
habitats.For 1981 through 1984,the total slough escapement of sockeye
salmon in the middle Susitna River ranged from 1,100 to 2,200 fish (Barr"ett et
al.1985).Thus,the middle Susitna River conta1''1S less than one percent of
the sockeye spawning within the Susitna River basin.
Habitat Utilization.Although sockeye salmon spawn almost exclusively in
slough habitats in the middle Susitna River,a limited amount of spawning
occurs in mainstem,side-channel and tributary habitats.Approximately 95
percent of the sockeye salmon spawned in side sloughs and upland sloughs,
while the remaining percent used side channel,mainstem,and tributary
habitats.Spclwning occurred in sloughs during the last week of August and the
first week of September.Chum salmon spawned in all areas where sockeye were
reported (Barrett et al.1984,1985).
Three out of 23 sloughs contri buted about 90 percent of the peak count of
spawning sockeye in the middle Susitna River (Table IV-3).These three
sloughs 11,8A,and 21 (Barrett et al.1984,1985)are also important chum
salmon spawning areas and contained 60 percent peak count of slough spawning
'chum sal mon.
Spawning sites other than sloughs were located in the following areas.Three
mainstem spawning sites were located between RM 138.6 and 138.9,at RM 139.0,
and at RM 141.6 (Barrett et al.1985).Seven side-channel spawning sites were
used by sockeye between RM 131 and 142 with Side Channel 11 at RM 134.6,and
Side Channel 21 at RM 141.0 containing the most fish.Only 33 sockeye were
IV-4
Table IV-3.Second-run sockeye salmon total slough escapement in the middle
Susitna River,1981-1984.
-Slough River Mil e 1981 1982 1983 1984
Four-Year
Average
-1 99.6 0 0 0 26 7
2 100.2 0 0 0 18 5
3B 101.4 0 0 10 36 12
~3A 101.9 13 0 0 29 11
5 107.6 0 0 0 3 1
8 113.7 0 ·0 0 5 1
,~8e 121.9 0 5 0 0 1
88 122.2 0 13 0 0 3
Moose 123.5 0 20 31 0 13
8A 125.1 195 131 130 532 247
~8 126.3 0 20 10 23 13
9 128.3 18 13 0 16 12
98 129.2 212 0 0 18 58-9A 133.8 4 o .0 0 1
11 135.3 1,620 1,199 564 1,280 1,166
15 137.2 0 0 0 3 1
~~17 138.9 11 0 11 26 12
19 139.7 42 0 10 29 20
21 141.1 63 87 294 154 150
22 144.5 0 0 0 5 1-
Total 2,178 1,488 1,060 2,203 1,732(1)
Source:Barrett et ale 1984,1985
(1)Four-year average of totals
-
-
IV-5
-
-
-
observed spawnling in mainstem and side channels (Barrett et ale 1985,Jennings
1985).UnlikE~chum salmon,spawning sockeye made little use of tributaries.
Spawning activity was recorded only in Portage Creek and then only one pair of
fish (Barrett et ale 1985).
Habitat Requir'ements.Adult sockeye salmon have specific habitat requirements
for spawning iind the selection of redd sites.Since most of the spawning in
the middle Susitnariver occurs in side-slough habitats,passage into these
habitats is an important consideration.For fish passage,hydraulic condi-
t ions appear to be the cantrall i ng factors;a speci fi c water depth must be
exceeded and ,~ater velocities must be within the swimming capabilities of the
fish {Bell 1973,Thompson 1972}.Tolerance limits associated with depth and
velocity depend on size and swimming capabilites.Generally,smaller fish
tolerate shallower depths and require lower velocities.
In general,depths less than 0.5 ft have been associated with passage
difficulty f01r adult salmon (Thompson 1972,Blakely et ale 1985).However,
shallower depths can be negotiated over short distances.Studies conducted in
side sloughs of the middle Susitna River indicate that adult chum salmon can
pass through passage reaches with thalweg depths of 0.3 ft for a distance of
80 feet (Figure IV-I)(Blakely et ale 1985,ADF&G 1985).Sockeye salmon are
smaller than chum salmon and have better swimming performance (Barrett 1984,
1985;Bell 1973).Thus,sockeye salmon can successfully negotiate shallower
depths than chum salmon,and the analyses of chum salmon passage can be used
to provide a conservative passage evaluation for sockeye salmon.
Habitat 'requirements for spawning salmon in Susitna River habitats were
defined using four variables:depth,velocity,substrate and upwelling.
Habitat SUitability criteria were developed for spawning sockeye salmon in
side-sl~ugh habitats are presented in Figures IV-2 and IV-3 (Vincent-Lant et
ale 1984b).Compared with sockeye salmon in other river systems,
slough-spawning sockeye salmon used a relatively narrow range of depth and
velocities,but a wider range of substrates.Mean depth and velocity
associated with sockeye spawning in slough habitats were 0.8 ft and 0.2 fps
respectively (n=81).In other drainages,usable depths ranged from 0.5 to
6.0 ft and optimal water velocities from 0.5 to 2.5 fps (Hoopes 1961;Chambers
IV-6
1 1 -)l 1 1 ])1 1 )1 t )
0.9 -
0.8 -
SALMON PASSAGE CRITERIA THRESHOLDS
I
---CRITERIA CURVE I
(1982 -83 DATA)t-I.2
--PASSAGE CRITERIA THRESHOLDS
(1984 DATA)I-1.1
'-1.0
Source:Blakely et al.1985.
o
0.1 ~
~O.2
j ~~I
0.0 I I I I I I I I I I I I I I I I I I i 0.0
20 40 60 80 100 120 140 1 60 180 200
PASSAGE REACH LENGTH (FEET)
LINE A LINE 8
;:-0.7 _COORDINATES·COORDINATES·
LaJ -X--L ...x....:L t-0 9 i=
lIJ 0 0.32 0 020 •LaJ
.u..0.6 _200 0.37 200 025 Wu.._~0.8-
~~f:i 0.5 -"'0.7 Ii:
o SUCCESSFUL PASSAGE ~O 6 ~
H Wo ....._.C)
<:C)UJ
J ~~A _-----O.!S ~
en --------.0.3-,----------------------------::.~__,(II#SUCCESSFUL PASSAGE WITH DIFFICULTY AND EXPOSURE _-_.~O.4~
B --------------~0.2 "1-0.3
---'UNSUCCESSFUL PASSAGE
Figure IV·I.Comparison of revised passage criteria thresholds for
successful and unsuccessful passage of chum salmon with
Criteria Curve I.
SOCKEYE SALMON
SUITABILITY CRITERIA CURVE
DEPTH
1.0
••
••SUITABILITY CRITERIA
.7 SUITABILITY
i RteIIl.INDEX
••0.00 0.0
0.20 0.0
pt~i .:1 0.30 0.2
0.&0 0.'.
.4 0.75 1.0
'.00 1,0
.3
.2
.1
7.03.0 4.0 :1.0 6.0
OEPTH (F'T)
2.01.0
o .LL__----<__._-_-__-__-_--_-.....
'.0
.-
VELOCITY
1.0T"---~
.S!
.8
SUITABILITY CRITERIA
.7
i .6
i ::
.3
VELOCITY
0.0
1.0
2.0
3.0
•.5
SUITABILITY
INDEX
1.0
1.0
0.5
0.1
0.0
.2
.,
-1.0 2.0 3.0 4.0
VELOCITY (FT/SEC)
5.0 .
Figure IV-2.Depth and velocity habitat requirements for spawning sockeye in
the middle Susitna River.
Source:Vincent-Lang et ale 1984b.
IV-8
.....
-
.....
-
.....
1.0
•iii
.8
.7
~
0 .6ir:
5 .s
~.4~
.3
.2
.1
0
Figure IV-3 ..
SOCKEYE SALMON
SUITABILITY CRITERIA CURVE
SUBSTRATE
IUISTIIATI ~IlIlTlCLl SUIT••lun
COOl ......!!!!-.IIIOU
I II II'-T 0.00
2 0.00
,SA SAIIO 0.00
..0.10
S SG VI.I"0.&0
•0 .•&
,LI 1-'"1.00
:IlU ,••":::
:~co &-10"g:;~
:1 10 >10"::~:
2 3 4 S 8 7 8 9 10 11 12 13
SUBSTRATE
Substrate utilization by spawning sockeye salmon in the middle
Susitna River.
.....
-
.-
Source:Vincent-Lang et al.1984b •
IV-9
""",
!
.....
....
1954,1955,Dehl i sl e and Cl ay 1961,Baldrige and Tri hey 1982).The narrow
range of velocities and depths utilized by sockeye salmon in the middle
Susitna River appear to be related to available conditions rather than
distinct preferences for lower values.Water depths in slough habitats during
spawning usually ranged from 0.1 to 2.5 ft with a mean depths of approximately
0.6 ft.Ve 1oc:it i es present duri ng spawn i ng ranged from 0.0 to 1.5 fps wi th a
mean of approximately 0.3 fps.
A wide range of substrate sizes were used by spawning sockeye salmon in the
middle Susitn;a River.Redds were excavated in silt-covered gravels and in
large gravel-cobble mixtures.Usable substrate for spawning was limited by
the fishes'ability to excavate the redd.A review of other studies indicates
that sockeye clppear to prefer substrate sizes between 1 and 5 in.in diameter
(Hoopes 1962,Baldrige and Trihey 1982,Jennings 1985).
Upwelling is eln important component of sockeye spawning habitat in the middle
Susitna River (Vincent-Lang et al.1984b).In sloughs and side channels,
sockeye salmon spawn in areas associated with upwell ing.The presence of
upwelling allows fish to use smaller size substrate particles for spawning
conditions that have been found to be detrimental to embryo development in
other systems (Silver et al.1963,Shumway et al.1964,Koski 1966).Upwelling
water prevents the disruption of intragavel flow and inhibition of oxygen and
metabolic waste transport usually associated with silty substrates.
The habitat re!quirements of spawning sockeye in the Susitna River drainage are
similar to those associated with chum salmon,a primary evaluation species.
---Ftgure IV-4--pY'es-ents a comparison of habitat suitability criteria developed in
slough and side channel habitats for spawning chum and sockeye salmon
(Vincent-Lang et al.1984b).The depth and velocity habitat sUitability
curves for the two species are almost overlapping;sockeye salmon use slightly
lower depths clnd velocity.Sockeye utilization of smaller substrate particles
is less than c:hum.However,these differences are sl ight.
Habitat Availability.Since the habitat utilization patterns and requirements
of sockeye salmon are similar to those for chum salmon,the detailed habitat
modelling presented for chum salmon can be applied to sockeye salmon.Habitat
IV-I0
_.
CHUM AND SOCKEYE SALMON
SUITABILITY CRITERIA CURVE
VELOCITY
LEGEND
_CHUM
__SOCKEYE
SUITABILITY CRITERIA
SUITABILITY INDEX
Velocjty ~Sockeye
1.00
1.00
0.75
0.50
0.30
0.10
0.00
1.00
1.00
0.89
0.63
0.36
0.18
0.00
o
1.0
1.5
2.0
2.5
3.0
4.5
1.0
.9
.8
.7
~
0 .83;
5 .5
!.4:::)en
.3
.2
.1
0
"""
-
0.5 1 .0 1.5 2.0 2.5 3.0 3.5.4.0 4.5
VELOCIlY (FTjSEC)
DEPTH
-
1.0
.9 (
.8 II
.7 I
~.8 I
3;I5.5 I~.4 Ii
.3 I
.2 I
.1 I
0
1.0
LEGEND
_CHUM
__SOCKEYE
SUITABILITY CRITERIA
SUITABILITY INDEX
tbwD Sockeye
o 0.00 0.00
0.2 0.00 0.00
·-0.3 0.01 -.0.20
0.5 0.20 0.90
0.75 0.87 1.00
0.8 1.00 1.00
8.0 1.00 1.00
2.0 3.0 4.0 5.0 8.0 7.0 8.0
DEPTH eFT)
Source:Vincent-Lang et al.1984b.
Figure IV·4.Comparison of habitat requirements for sockeye and chum salmon.
IV-ll
-CHUM AND SOCKEYE SALMON
SUITABILITY CRITERIA CURVE
SUBSTRATE
2 3 4 5 6 7 8 9 10 11 12 13
SUBSTRATE
1.0 LEGEND
.9 ~CHU'"
.8 •SOCKEYE
.7
WITMllIn CII1IUAi'::i .-nATt PMTICl.I SlIITMILln I"c .6 -'IIIL-JUL QIIII .IlUQl~
5 I 51 SILT O.GO O.W
.S I 1.00 I.W
1 SA ~O.ta O.W
~4 O.OS 0.11
J 51 1/0·1"_.1.11 0••
A ,I .•I ••=>,lC I...S-1.GO I.WlI)0 1.GO 1."
.3 ,lilt 1-5"I.GO I ••
1.I ••I ••
11 CO I-II"I.~...
11 '.11 0 ••
.2 11 ...11"I.W ...
.1
0
,.....
-
-
Source:Vincent-lang et a1.1984a.
-
Figure IV-4.Continued.
sockeYE!and chum salmon.
Comparison of habitat requirements for
-
IV-12
-
-
-
simulations completed for chum salmon in side-slough and side-channel habitats
would describe almost all (98%)sockeye spawning activity in the middle
Susitna River.
ADD SECTION BASED ON CHUM SALMON RESULTS.
Juveniles
Middle Susitna River juvenile sockeye can be separated into three groups based
on different 1i fe hi stori es.The fi rst pattern is for juveni 1e sockeye to
spend their entire freshwater period rearing in the middle river,then
outmigrating to the ocean during the spring of their second year.The second
pattern is for'fish to spend 3 to 4 months of their first summer in the middle
river,move t,O areas below the Chul itna River confluence to overwinter,and
then outmigrate to Cook Inlet during the spring of their second year.The
third pattern is for juvenile sockeye to spend u~to six months in the middle
Susitna River before beginning a downstream migration,entering the ocean in
the summer or fall as 0+fish.Those fish that go directly to sea as age 0+
have a low survival rate (ADF&G 1982a,Barrett et al.1984,1985).Most of
.the returning adult sockeye had spent 1 year in freshwater.
The population size of age 0+sockeye was estimated in the middle Susitna
River.In 1983 and 1984,the population size was estimated to be 575,000 and
299,000 respectively,using Schaeffer's estimate (Schmidt et al.1984,1985).
Most juvenile sockeye leave the middle Susitna River at age 0+and move into
the Susitna Riiver below Talkeetna.In 1983 and 1984,ADF&G reported that age
1+fish accounted for less than 1 percent of outmigrants sampled in the middle
Susitna River ..
Peak.outmigration generally occurs from late June to early July,although
outmigration from the middle Susitna River continues from mid June through mid
October (ADF&G 1983b,and Schmidt et al.1984).
Habitat Utilization.In the middle Susitna River,juvenile sockeye salmon use
upland sloughs and side sloughs (Figure IV-5)(Schmidt et al.1984,1985).In
1982 and 1983,90 percent were found in upland and side sloughs and 10 percent
IV-13
))}
Nin.SlouGh'
Combin.d
]J )}
\A
j
or"-f"
"
l '),»
Seven Malnatem
S it.a Com bi ned
-'--Maln',t.m II
-SiouQh 20
l )
UPLAND SLOUGHS
SlouOh 19
8.4%
SlouOh 5-----
MAINSTEM 81 DE
CHANNELS
SIDE SLOUGHS
TRIBUTARI ES
H<:
I.....
~
CO~BINE.P·MACROHABITAT
.",'TYPES
Figure IV-5.Habitat.ut"il1zation by juvenile sockeye salmon.
Source:Schmidt et al.1984.
-,
.....
-.
in tributary mouths and side channel s (ADF&G 1983b,Schmidt et al.1984).
Utilization of rearing areas by sockeye juveniles appears to be related to
proximity of spawning areas and many juvenil e sockeye are found in natal
sloughs like Slough 11.Upland Slough 6A,however,is an exception as the
nearest spawning areas are 10 to 12 mil es upstream.The most important of
these rearing areas were Upland Slough 6A and Side Slough 11 which account for
34 and 33 percent,respectively,of juveniles in middle Susitna River {Schmidt
et al.1984,1985}.
Some overwintl~ring of juvenile sockeye in the middle Susitna River has been
documented in sloughs 9 and 11 {ADF&G 1983c,Schmidt et al.1984,1985}.
However,catches have been low,indicating that the middle reach is not used
extensively fClr overwintering by juvenile sockeye.
Habitat Requirements.Habitat suitability criteria was developed in side and
upland sloughs to descri be juvenil e habi tat preferences (Fi gures IV-6 and
IV-7).Depths utilized by juvenile sockeye salmon range from 0.1 to 4.S ft
and within this range,depths greater than 1.6 ft were preferred.Velocities
util ized ranged from 0.0 to 1.3 fps and preferred velocities from 0.0 to
0.3 fps.Juvenile sockeye appear to prefer emergent and aquatic vegetation
and undercut banks.Habitat utilization data for cover suggest that sockeye
salmon juveniles are less dependent on cover than other salmon.Sockeye use
schooling behavior as a defense against predation rather than refuge habitat
associated with cover (Suchanek et al.1985).Sockeye juveniles also appear
to avoid turbid water (Dugan et al.1984).
Habitat requirements of juvenile sockeye in the Susitna River are similar to
those reported for the Kenai River by Burger et al.{1983}.Burger et al.
found juvenill~sockeye occupying areas with velocities from 0.0 to 0.3 fps,
and often in clssociation with aquatic vegetation that was used as cover.They
found sockeye juvenil es usi ng shallower depths than noted for the Susitna
River but this may be related to low water conditions occurring during the
sampling .
Sockeye juveniles appear to respond most to wat~r velocities and cover is of
secondary importance.Depth,after it exceeds a threshold val ue,does not
IV-IS
"'"
-
It STANDARD ERROR
N -NUMBER OF CELLS SAMPLED
N-151 --1983
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 4.5
DEPTH (ft)
~0.30 ~I!'.STANDARD ERRORN•~z
,~~ffi 0.2!S N - NUMBER OF CELLS SAMPLED.JU)--1983 1.0"''''US:0.20 --.1984 (REVISED)X
'"...-IL.0.8 00",Z
z>--...0'"o.le ~1ft >--~2 0.6 ...
""""~U -~o ...J
~en 0.10 -
0.4 en
0%«
""""
~......
Q.i 0.05 ::>0.2 en
r-0.00 0.0
!
0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 4.8
VELOCITY (ft/sec)Source:Suchanek et al.-
Figure IV-5.Depth and velocity habitat requirements for juvenile sockeye in
the Susitna River.
IV-16
--~~~J }))-1 }I .}1 J r l 1
0.00 I I I I I I I I I I I I 0.0
N-03'N-233 N-'Ol N-41 N-22
(0-5%)(6-25"')(26-50"')(51-15%.(16-100"')
PERCENT COVER CATEGORIES
1.0
)(w0.8 0
~
0.6 )-...
::::i
0.4 m
c(
t-
0.2 5
CQ
I!STANDARD ERROR
N-NUMBER OF CELLS SAMPLED
--1983
---1984
0.30
0.30...
(l)Z
...Jw 5...J U)0.2ww
00::
LL.Q.0.20
01iJ
z>-
52 ~0.10"'00::00el)
Q.0.100::3:
0::...c:L_
~0.05
c:J SOCKEYE.1983
IZ1J SOCKEYE.1984
N -NUMBER OF CELLS
SAMPLED
1.00,
0.00
~I-X:.....11:..,uz ..,~elZ I-::r:II:i ::)z ILl..,....-0 eI..,zC ZO ..,uC ...10 CD 1--«~iijii:..,-~CD CI-eI~..,acID CD.J CD ::)C c«z~a ..,CD::)::)01--'eI «I-u000g;Cw C_"''''Z UCD ~«:::Eel 0
::)eI W..,ZWW>>>
0
COVER TYPE
0.T5
)(
W
Q
Z-0.50i~~G 11 ~11 ~~on
~..0-~HI-li:"<:-........lI:I~
.....G
-.JC...:;•
0.25
Figure IV·7.Cover suitabilities for juvenile sockeye salmon in the Susitna
River.
Source:Suchanek et al.1985
....
-
,~
-
appear to be an important factor in determining habitat utilization.Velocity
habitat suitability curves for Kenai River sockeye juveniles had optimum at
0.0 fps,with little use at velocities greater than 0.6 fps (Burger et al.
1983).
Food habits of juvenil e sockeye were examined in July and August of 1982.In
sloughs 8A and 11,chironomid larvae,pupae,and adults were found to be the
numeri cally dominant food item sel ected.Juveni 1e sockeye preferred
chironomid larvae.Other food items consumed included cladocerans and
copepods in Slough 11,and a variety of aquatic and terrestrial insects from
both sloughs.
Growth rates of juvenile sockeye were estimated.Growth ceased at a critical
"size around 50-55 mm.Schmidt et al.(1984)suggested that juveniles migrated
downstream during July and August in search of better rearing habitat
(plankton-rich areas).Growth was measured after August in less than 2
percent of the outmigrating age 0+fish from the middle Susitna River.Growth
was also measured on age 1+fish indicating that both age 0+and age 1+fry
were growing through the winter and early spring prior to outmigration from
the middle Susitna River.
Habitat Availability.Habitat requirements for r~aring sockeye salmon differ
from those of chinook salmon,the primary evaluation species with respect to
both macro-and mi crohabi tat ut il i zati on.Therefore the deta i"l ed habi tat
simulations presented for chinook salmon juveniles would not be applicable to
juvenile sockl!ye salmon.Habitat availability for sockeye salmon juveniles
can be evaluated using gross surface area (Figure IV-8).Rearing habitat for
juvenile sockE~ye in the middle Susitna River appears to be scarce.Deeper,
lower velocity,and clear water are uncommon in middle Susitna River (Hale
1984,Schmidt et al.1984).Slough 11 was favorable for rearing as it
breaches only at high discharges (42,000 cfs)therefore maintaining more
lake-like rearing conditions.Slough 6A,the most important slough,also has
low velocity a.nd clear water (Schmidt et al.1984",:.
IV-18
-----<-------~"'------------------..,....-
1 1 l ~J ~.....)l'1 )1 j J '})
25
24
23
22
..-
UlW
0::::21~'-'"
L5~20
WU<
H ~19
<:
I ::J
I-"
Ul
1.0
18
17
UPLAND SLOUGH
16
15 'I I I I I I I I I
5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5
MAINSTEM DISCHARGE x 1000 (FPS)
Figure IV-S.Habitat availability for juvenile sockeye salmon based on
surface area response of important habitat types.
-
r
-
-
-.
-
-
Coho Salmon
Adults
Susitna River coho salmon rank third in commercial value to sockeye and chum
salmon.The average annual catch of Susitna River coho in the fishery for the
past 31 years is 264,000 fish (Jennings 1985).Coho salmon enter the middle
Susitna River during the last week of July and are numerous until the first
week of September (Barrett et al.1984,1985).The timing of the migration
appears to be relatively consistent from year to year with peak migration
occurring between August 1 and August 16 (Barrett et al.1984,1985).
Spawning activity begins in late August and continues through early October
(AOF&G 1981a,1982a~Barrett et al.1984,1985).
Most of the coho salmon entering the Susitna River spawn in tributaries
downstream of RM 80 (Barrett et al.1985)and rel atively few spawn in the
middle SusitmL River.An average of 5,700 adult coho passed the Talkeetna
Station (RM 103)annually,while 1,600 coho passed the Curry Station (RM 120)
(Table IV-2).
Spawning ground surveys indicate these escapements overestimate the number of
fish spawning in the middle Susitna River.In 1984,an estimated 75 percent
.of the adult coho escapement to Talkeetna Station could not be accounted for
on the spawni ng grounds and may have returned downri ver to spawn.Based on
this estimate of milling,2,950 coho spawned in the middle Susitna River in
.1984 which represents less than 2 percent of the 1984 coho escapement to the
Susitna River (Barrett et al.1985).
Habitat Utilization.In the middle Susitna River,coho salmon spawn
principally in tributaries.Twelve tributaries in the middle river supported
spawning (Tablle IV-4).Tributary spawning occurs during the third week of
September to the 2nd week of October.The most important tributaries for coho
spawning are Gash Creek (RM 111.6),Indian River (RM 138.6),Whiskers Creek
(RM 101.4),and Chase Creek (RM 106.9)(Barrett et al.1984,1985).
IV-20
Table IV-4.Coho salmon peak index counts in streams upstream of RM 98.6,
-,1981-1984.
River Four-Year
Stream Mile 1981 .1982 1983 1984 Average
.Whi skers Creek 101.4 70 176 115 301 166
Chase Creek 106.9 80 36 12 239 92
Slash Creek 111.2 0 6 2 5 3
Gash Creek 111.6 141 74 19 234 117
Lane Creek 113.6 3 5 2 24 9
Lower McKenzie Creek 116.2 56 133 18 24 58
Little Portage Creek 117.7 0 8 0 0 2
Fourth of July Creek 131.1 1 4 3 8 4
Gold Creek 136.7 0 1 0 0 0
Indian River 138.6 85 101 53 465 176
Jack Long Creek 144.5 0 1 1 6 2
Portage Creek 148.9 22 88 15 128 63
-Total 458 633 240 1,434
~Source:ADF&G 1981a,1982a;Barrett et ale 1984,1985
1 Four-year average of totals
IV-21
-
-
-
~'
-
,p.-,
Only 15 coho :salmon spawned in habitats other than tributaries.The mainstem
spawning sites included sites at RM ,117.6,two sites between RM 114-148.2,and
'one site at Rt1131.1 (Meyer et al.1984;ADF&G 1982a).Coho spawned in Slough
8A in 1983 (V'incent-Lang et al.1984a).Only one site RM 131.1 near Fourth of
July Creek was used consi stently.All others were used in one out of four
years.
Habitat Requirements.Habitat sUitability criteria were developed for
spawning coho salmon in the middle Susitna River from previously published
info-rmation (Figures IV-9 and IV-10)..SUitability criteria developed on other
Al askan streams served as the basi S for Susitna River coho criteri a (Wil son et
al.1981).Criteria developed for two rivers on Kodiak were modified by
biologists familiar with coho salmon in the Susitna River (Vincent-Lang et al.
1984a).Habitat requirements for spawning coho in the Susitna River included
depths rangi nl9 from 0.3 to 5 ft wi th optima1 values between 0.7 and 5.0 ft.
Water velocitJ'ranged from 0.1 fps to 4.0 fps with optimal values between 1.5
and 2.5 fps.Spawning substrates ranged in slze from sand to rubble with
small and 1 arge gravel provide optimal conditions (Vincent-Lang et al.1984a).
Susitna River fish used a broader range of depth than Kodiak fish but similar
velocities.They also used smaller substrates than Kodiak fish.Information
"_reported on habitat characteristics of coho spawning areas in the Pacific
Northwest are similar to Susitna values (Chambers et al.1954,1955,Smith
1973,Reiser and Bjornn 1979).These studies generally reported tolerance
ranges narrOWE!r than those developed for Susitna River salmon.
Habitat Avail abil ity.Since habitat util ization patterns and habitat
requirements differ between spawning coho and chum salmon,analyses conducted
for habitat availability for spawning chum salmon are not applicable to coho
salmon.The infl uence of mai nstem flow on habitat avail abil ity is addressed
us i ng the response of surface areas of habi tat types important to spawn i ng
coho.
Most coho salmon spawn in tributary habitat that are not directly influenced
by mainstem discharge.Some spawning occurs in tributary mouths and habitat
conditions in tributary mouths can be affected by mainstem discharge.
IV-22
COHO SAl.MON .-SUITABILITY CRITERIA CURV£
DEPTH
Tlrr.,1..11.CrU.,I.00--0 (wnl.If ••.11111
0 o 1..11t1l.Cr Iterl.
1.0 ~0
\••r \
I \
••f \
\
)(I \SUITABILITY CRITERIAIII.f r \
TERROR LAKE SUSITMA.0 I \"""!~CRITERIA CRIT£RIA••J \
)-I \0.3 0.00
t:.!I ~0.1 0.00
..J I \O.T 1.00 1.00,-iii ...I \1.0 1.00~I \1.0 .0.10
.5 r \1.1 0.10:;)I \...0 0.10 1.00(I)
.2 I ),.1.0 0.00
I ,
.1 I '0..I "
0 ,.......-i
0 2 3 ..5
DEPTH (FTl
--VELOCITY
1.00
0.50
0.00
SUSITNA
CRITERIA
0.00
0.10
0.50
'.00
TERROR LAKE
CRITERI~
0.00
0.10
0.50
0.90
1.00
1.00
0.50
0.10
0.00
o 0 Terr.Lolle Crileria
(Wiltoll .t c;L 1981)
~- --0 SutitllO Crileria
SUITABILITY CRITERIA
VELOCITY
0.01
0.10
0.50
1.00
1.10
2.50
1.00
1.50
4.00
•
\
\
\
\
\
\
\
\
tt ,,
2
o-t6---..---__--,.-.-~~-.....,--_,o
.1
.2
1.0
.9..
)(
~.7
Z-..
>-t:.5
..J:......
:;.3
(I)
-
-
VELOCITY (FTISEC)
Figure IV-9.Depth and velocity habitat requirements for spawning coho
salmon in the middle Susitna River.
-
Source:Vincent-lang et al.1984a.
IV-23
-,
COHO
...5 6 7 8 9 10 11 12 13
SUBSTRATE CODE
-
-
-
I
I
I
.-\
\
\
J \
I \
I \
\
\
\
\
\
\
\
\
\
~SUSITNA
__TERROR LAKE
SUITAlILIn CllI1lUA
SWSTllAn 'MTICL£TElIAOIl LW SUSITIIA
-'llIIL--m.L....wIWL WtWl
,I II SILT a.oo a.oora.oo o.aaISASNIIa.oo a.50•0.00 1.005saIII.I'0.50 1.00t1.00 1.007LII •J'1.00 0.75•0.50 O.lO,IN J ..5~0.00 0.00100.00 0.00IICO5•10·0.00 0.00It0.00 0.00II10)01011 0.00 0.00
....
Figure IV··IO.
Source:Vincent-lang et al.1984a,
Substrate utilization by spawning coho salmon in the middle
Sus itna River.
IV-24
-
-
Mainstem flow can affect water depth,water velocity,and areal extent of
tributary mouths.Since adult coho must pass through tributary mouths to gain
access to upstream spawning areas,passage may indirectly affect tributary
spawning.In Susitna River habitats,passage conditions into tributaries is
mainly controlled by tributary flow rather than mainstem stage.
An estimate of the response of tributary mouth habitats to mainstem flow was
developed from the surface area response of tributary mouth habitats (Figure
IV-ll).At lower mainstem discharges (5000 to 7500),tributary mouth area
remains constant.Between 7500 and 12,500 tributary mouth area increases,
with the most gains between 10,600 and 1~!,500.At flows above 12,500
tributary mouth area gradually declines with higher flows.
Juveniles
Most juvenile coho spend two years or more in freshwater before outmigrating
'to the ocean (ADF&G 1981b, 1983b,Schmidt et a'l.1984).Sampl ing conducted by
ADF&G indicate that many age 0+fish leave the middle river in August to rear
in downstream habitats.However,outmigration of Age 1+in May and June
indicate that a substantial number of juvenile coho overwinter in middle river
habitats and leave the following summer (Schmidt et ale 1984).
Juvenile coho salmon are second in abundance to juvneile chinook salmon in
middle Susitna River habitats (Stratton 1985).The majority of fish are and
0+.Capture data indicate that age 0+fish comprise approximately 90 per cent
of the summer populations.The remaining 10 percent is comprised mostly of
age 1+fi sh wi th a few age 2+fish~{l ess than 1 percent).
Habitat Utilization.Most juvenile coho were found in tributaries,and Upland
Slough 51 and 35 percent respectively (Figure IV-12).The proximity of
spawning areas may influence the utilization Clf rearing areas.The important
tributaries showing the higest densities of juvenile fish were those recieving
the largest escapements:Chase Creek,Whiskers Creek,and Indian River.The
only slough habitats used were downstream of tributary spawning areas:
Whiskers Creek Slough and Slough 8.Important upland sloughs were sloughs 6A
and 5.Neither is near spawning areas,howevelr,both are in the lower portion
IV-25
,t&ii4JIlIW4 !4 4:Z;:W1U$IIJ1l1$"lit "lW aAi.Mi~---------------"""""'--
J 1 )
30
1 j 1 1 1 l -1 1 1 ,)
25
'Ii)
I.I.Ja:::
~-...
~a:::20
4:
W
1-1
~
<:
La...:.
I
a:::
IV ~
0'1
15
TRIBUTARY MOUTH
I10 I I I I I I
I I I
5.0 7.5 10.0 12.5 15.0 17.5 20.0 ·22.5
MAINSTEM DISCHARGE x 1 000 (FPS)
Figure IV-II.Habitat availability for spawning coho salmon based on area
response of important habitat types.
)j J )}1 ).~-11 )1 .-1 ]
Wh i,kers Cre.k
SlouOh ,
./Eleven SlouGhs
~'-.""Combined
1.2 0/0
Whlske,.
Cr.ek \
SlouGh
Mainltem No.2
9.8 OJo
-I Fourt.en Mainlte..Side
Channe.1 Combined
0.5%
UPLAND SLOUGHS
MAINSTEM SID E
CHANNEL
9..8 %
51.0 0/.
SIDE SLOUGHS
Four Tributaries
Comb Ined 3.2 %
Chas.
Creele .~
TRIBUTARIES~
H
'f I ndian River
~6.9 %
Whiske,.
Creek
COMBINED MACROHABITAT
TYPES
Figure IV-12.Habitat utilization by juvenile sockey salmon in the middle
Susitna River.
Source:S~hmirlt At ~1 1~OA
-
-
·of the middle Susitna River.Fish are emigrating in these areas due to
presence of suitable rearing conditions.Juvenile cohos were rarely found in
side channels.Side channels appear to be used more as a corridor for
redistribution rather t~an as a rearing area (Dugan et al.1984).
The habitat util ization changes season'ally for juvenile coho as they leave
natal streams and seek rearing areas in other habitats.Juvenile coho
densities were usually low and fish were widely distributed during July and
August when densities peaked.Upland sloughs had higher densities of juvenile
coho from late July through late September,whereas tributaries had higher
densities during late June.Side slough densities of juvenile coho were
higher during July and August.Overall,tributaries had the highest densities
of rearing juveniles.
Many juvenile coho overwinter in middle Susitni!River habitats.During winter
juvenile coho were most abundant in Whiskers Creek Side Slough,and Upland
Slough 6A during 1981 to 1983.In the winter of 1984-85,juvenile coho were
most abundant in the Indian River and Slough 10.A few juveniles were also
captured in sloughs 9A and 22.
There appears to be a relationship between juvenile coho outmigration and
mainstem discharge (Roth and Stratton 1984).The outmigration rate of age 0+
cohos was higher in May through early July in 1984 than for the same period in
1983.This difference may have been caused by higher tributary streamflows in
1984 accelerating outmigration from tributar'y habitats (Roth and Stratton
1984).
Habitat Requirements.The habitat requirements for three physical variables
were evaluated for j uven il e coho sal man.Depth ,vel oc ity ,and cover were
analyzed to develop habitat suitability criteria (Figures IV-13 and IV-14).
°In the Susitna River,coho salmon used water depths ranging from 0.1 to 4.5 ft
with depths greater than 1.6 ft being the most preferred depth.Water depths
used by juvenil e coho were simi 1ar to other ri vers.On the Terror and
Kizhuyak rivers,depths ranged from 0.5-5.0 ft with most fish found at depths
between 0.5 and 2.2 ft.Bovee (1978)states that coho juveniles prefer
IV-28
f'-'
0 2.5 I±STANOARD ERROR
:z:N II NUMBER OF CELLS SAMPLED0
U 2.0 H-I51 --1983•
~.J N-2e.J )(
LIJ I.S 1.0 ~U.....0.8 ~:z:N·e4
u 1.0 >-...0.6 ...,~-.J0.4 -z 0.8 £II
««
LaJ 0.2 ~-2 0.0 :)
~0.0 (/)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 4.5
DEPTH (ft)
N=33
ItSTANOARD ERROR3.0
0 N-NUMBER OF CELLS SAMPLED-:I:2..5 N=67
0 --1983
(.)
1.0
'.J 2.0
.J )(
laJ 0.8 LIJ
(.)Q
.....1.5
N"I47 1
N=9 z
:I:0.6(.)'.=14 >......«1.0 -(.)0.4 .J
Z £II««0.5 ...LIJ 0.2 -~:)
(/)
0.0 0.0
0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.2
..-VELOCITY (ftlsee)Source:Suchanek et a1.1985
Figure IV-13.Depth and velocity requirements for juvenile sockeye salmon in
the Susitna River.
IV-29
I ----]j 1 J ...J J ]J J 1 1 J J
t
/.o
0.8 i
0.6
>-...
0.4 =
CD
~
0.2 :;
(I)
I±STANDARD ERROR
N.NUMBER OF CELLS SAMPLED
--1983
---1984
3.5
0.0 'I."l'I I "I &0.0
N-13T N-81 N-66 N-40 N-22
(0·5%)(6·25%)(26·50%)(51·75%)(76·100-..)
PERCENT COVER CATEGORIES
o 3.0
:J:o
o 2.5
...J
...J 2.01&1
U.....
:J:1.5
U
~
U 1.0
Z
c(
~0.5
CJ COHO.1983
G?Zd COHO.1984
N -NUMBER OF CELLS SAMPLED
••z1.00
0
0 10-N
Z Z
0.00
fI)....x:.....CI:A&'<JZ IU..J ~z ....z Q:
i ;:)z ~IU ..J -0 (l)IU zcr zO A&'<Jer ID ....-0:>t;Q;IU->CD ID O ~!i (l)!i....Cl:lD ID..J ID erer zer 0....0:):)0 ......JO:0:....<J00<Jo 0::erw (l)ero.lUlUz::r-0CD(!)o::tI:::Ii(l):;:)IU W lUlU Z
>>>
0
COVER TYPE
0.75
)(
III
0
~
)0-
!:0.50
H ~II ~I ~II 10
<:lit •
I C z
w ...
o :;
II ~t F0.l I l-en ~I ~n!•z
0.25-11 f011 f0j I m_
Figure IV-14.Cover suitabilities for juvenile sockeye salmon in the Susitna
River.
Source:Suchanek et al.1985
-
-
-
simil ar water depths rangi ng from 1.0 to 5.0 ft with the preferred depth at
2.0 ft.
Suitabilities assigned to water velocities werl~also similar to those in other
rivers.In the middle Susitna River,suitab11e water velocities ranged from
0.1 to 3.0 fps with optimal velocities 0.1 and 0.3 fps.In the Terror and
Kizhuyak rivers,water velocities utilized by coho salmon ranged from 0.0 to
3.5 fps with most fish found between 0.0 and 0.5 fps (Wi1 son et a1.1981).
Suitable velocities presented by Bovee (1978)ranged from 0.0 to 2.5 fps with
0.5 fps most preferred.
Coho utilized cover types ranging from debris to various sizes of substrate to
vegetation,with the highest preference for debris,undercut banks,and cobble
(Schmidt et a1.1985).
Winter habitat characteristics are described for several overwintering sites.
In general,these were characteri zed by a range in depth from 0.3 to 5.0 ft
and range in water velocity from 0.0 to 0.6 fps.Cover and percent were
variable.
The food habits of rearing juveniles were examined in 1978 and 1982.The
dominant and most preferred food item was chironomids.Other food items eaten
were other dipterans,and mayfly and stonef1y nymphs.In 1978,stomach
analyses showed that aquatic insect larvae were common in the spring,whereas
adu1 t insects were more common duri ng the summer and fall.Coho have also
been reported to feed on pi nk,chum,and sockeye juvenil es when abundant
(Scott and Crossman 1983).
Habitat Avail abi 1itv.A1though juvenil e coho salmon generally have habitat
requirements similar to chinook in clear water,coho salmon depend on
different habitat types.Juvenile coho salmon "re associated predominantly
with tributary,tributary mouth and upland .;lough habitats.Of these
habitats,mainstem discharge influences conditions in tributary mouths and to
a lesser extent,upland sloughs.Habitat availability as a function of
mainstem discharge was evaluated using surface area response for the habitat
types (Figure IV-IS).
IV-31
}j }
30
1 )}1 )
UPLAND SLOUGH
j ~J
25
..........
(Il
W
0::
U-<...-
~9t 20
w
H
U
<~
I
a::
w =>
IV
(Il
15
r-,-\
/\/
/
/
l'
/
/
/
/
/
/
\,
\
\
\
\
\
\
\
\
\
\,
__TRIBUTARY MOUTH
10 I I I I I I I I I I
5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5
MAINSTEM DISCHARGE x '000 (FPS)
Figure IV-IS.Habitat availability for juvenile coho salmon based on surface
area response of important habitat types.
r-
I
i
Pink Salmon
Adults
Susitna River pink salmon rank last in commercial value compared to the other
salmon in the River.The average annual odd-year harvest in the past 31 years
is 120,416 fish and the even-year harvest is 1,,576,646.Pink salmon move into
the middle river and spawn in the tributaries during the first three weeks of
August.The timing of the migration is relatively consistent from year to
year with the peak migration occurring between the last week of July and the
second week of August.
In the Susitna River,the dominant year class for pink salmon is the even-year
run (Table IV-2).The minimum even-year run averaged 1,138,400 fish annually
during 1982 and 1984,whereas the minimum odd-year escapement averaged 93,400
fish annually (Barrett et ale 1984,1985).Most of the pink salmon entering
the Susitna River spawn in the lower river,downstream of the Chul itna River
confl uence (Barrett et al.1984,1985).Based on 1984 resul ts,the pi nk
salmon that spawned in habitats associated 'wit"the middle Susitna River
comprised less than one percent of the total Susitna Basin escapement
(Jennings 1985).
The pink salmon escapement to Talkeetna Station averaged 5,900 fish annually
duri ng odd-years (1981 ,1983).Even-year escapements to Tal keetna Station
were 177,900 fish in 1982 and 10,950 fish in 1984 (Barrett et al.1984,1985).
The pink salmon escapement to Curry Station aver-aged 3,300 fish during odd
year~and 87,000 during even years (Barrett et ale 1984,1985).
Similar to the sockeye and coho escapements,a portion of the pink salmon
escapement to Tal keetna and Curry stations is co;npri sed of mi 11 i ng fi sh that
return downstream to spawn ..In 1984,about 85 percent of the pink salmon
escapement to Tal keetna Station was unaccounted for on the spawning grounds
and may have returned downstream to spawn (Barret"s et ale 1985).
Habitat Utilization.In the middle Susitna River,most pink salmon spawn in
tri butari es.The most important spawni ng streams are Indi an River,Portage
IV-33
~
i,
--
,~
Creek,Fourth of July Creek and Lane Creek for beth even and odd runs (Table
IV-5).Most of the spawning activity in tributaries occurs in the second week
of August and continues through the first week of September (Barrett et al.
1984,1985).
Although the majority of pink salmon spawn in tributaries,sloughs are also
used for spawning.Even-year pink salmon spawn in sloughs more than odd-year
pink salmon.The three most important sloughs were 8A,11,and 20.Sloughs
that supported fewer spawning fish,were3A,3B,5,8,Bushrod,8A,Moose,9,
9B,and 21.The spawning areas within sloughs 8A,9,11,20,and 21 had
tributary-like characteristics such as shanow riffles and gravel/rubble/
cobble substrates.Most of the spawning activity in the sloughs occurred
during the month of August and the 'first week of September (ADF&G 1981, 1982,
Barrett et al.1984,1985).
Habitat Requirements.Habitat requirements for spawning pink salmon in the
mi ddl e Sus i tna River.Su i tabil i ty criteri a developed from the Terror and
Kizhuyak rivers (Wilson et al.1981)were modified by biologists familiar with
pink salmon in the Susitna River (Figures IV-lEi and IV-17).The most preferred
water depths were 1.0 to 2.3 ft.The preferred water velocities ranged from 1
.to 2 fps,and preferred substrates ranged fr'om 1 to 3 inches in di ameter.
These preferred depths,water velocities,and substrates are well within the
ranges noted for pi nk sal man from other pclrts of Alaska and Wash i ngton
(Collings 1974,Graybill et al.1979,Wilson et al.1981,Estes and Kepler
1981).
--Habitat Availability.(Will be prOVided later)(fl~u.re 1\1·,18 will ba rnvldJ lto~)
·Juvenil es
The 1 ife history pattern for pink salmon fry is to outmigrate to the ocean
soon after emergence.Outmigration usually occurs during spring break-up (end
of May and early June)accompanied by ice and hi'gh discharge levels.
There has been no estimation of the s,ize of the fry population in the middle
Susitna River.Outmigrant traps collected six ~ry in 1982,245 fry in 1983
IV-34
Table IV-5.Pink salmon peak index counts in th~middle Susitna River,
1981-1984.
IV-35
,~
PINI<SALMONI
SUITABILITY CRITEFUA CURVE
DEPTH
0-- -'0 T."a,LCI~'erlt.,l,
(Wlltoll .,,•.I.,U
o 0 ,...11110 t,lttti.
1.0
\
.9 l \,
.8 I \,\SUITABILITY CRITERIA)(
l&I .,,\
TERRON LAKE SUSITNA0I\DEPTH CRlIE"'A CRITERIA:!:\.6 I \0.'0.00)-,~0.3 0.00.....~I 1.0 1.00 1.00:J
ii ,,
2.5 1.00.4 \3.0 0.50:!,
\,4.0 0.10 1.00j.,\
5.0 0.00fI),
\
.2 ,
\,
\
.1 ,
b..........,
.....
0
0 2 3 4 ~
DEPTH (FT)
VELOCITY
-
t.O
.9
.8
X
l&J .7
0
Z
.6
>-.....5:J
CD .4c:(....
3 .3
fI)
.2
.1
4
VELOCITY (FT/SEC)
6
e>---o T.rra,Lake Criteria
(Wil.o".t at.19811
C>--~Su.itnG C,it.,ia
SUITABILITY CRITERIA
TERROR LAKE SUSITNA
VELOCITY CRITERIA CRITERIA
0.08 0.00
0.10 0.'0 0.00
0.40 0.40 0.40
1.00 1.00 1.00
2.00 1.00 1.00
2.50 0.50
5.00 O.~O
3.50 0.10
4.00 0.10
5.00 0.00 0.00
.-
~, ,.
Figure IV-16.Depth and velocity habitat rl:!quirements for spawning coho in
the middle Susitna River .
Source:Vincent-Lang et aT.1984a.
IV-36
-
PINK SALMON
SUITABILITY CRITERIA CURVE
SUBSTRATE
c>--00 Terror Lake Crlt.rla
(WIIIOII .,at 1981)
1.0
.9 SUITABILITY CRITERIA
.8 SUBSTRATE PARTICLE TERROR LAKE SUSITNA
CODE SIZE CRITERIA CRITERIAX.~
1IJ .7 I 51 SILT 0.00020.00Z
3 SA SAND 0.00 0.00.6
~4 0.10 0.10~.5 5 SG 1/8 -,"0.7'0.7'
..J 6 1.00 1.00m.4 7 LG 1-3"1.00~8 1.00 1.00
J .3 9 I~U 3_5"0.50 0.50
(/)10 0.2'
.2 II (:0 5-10"0.00 0.00
12 0.00
.1 13 80 >10·0.00,
0 r-
I 2 3 4 5 6 7 8 9 10 1\12 13
SI SA 56 LG RU CO BIO
SUBSTRATE COOE
,-,
!
Figure IV-I7.Substrate utilization by spawning pink salmon in the middle
Susitna River.
Source:Vincent-Lang et al.1984a.
r
I IV 37
-
.-
_.
(will be provided later)
Figure IV-18.Habitat availability for spawning pink salmon based on area
response of important habitat types.
IV-38
,....
-
-
--
and 68 fry in 1984 (ADF&G 1983,Schmidt et al.1984,1985).The number of
even-year pink adults is thought to be about 10 times greater than the
odd-year escapement based on the spawning escapement.Therefore,the
outmi grat i on of fry is 1arger duri ng odd years ..
Habitat Utilization.(will be provided later)
Habitat Requirements.-Pink salmon fry outmigrate to the ocean soon after
emergence and little,if any,freshwater rearing occurs.Discharge is thought
to influence outmigration.Higher catches of pink fry have been directly
correlated with higher discharges (Schmidt et al.1984).The peak of the
outmigration of pink salmon fry occurred during June in 1983 and 1984 (Schmidt
et al.1984,1985).
ADD REQUIREMENTS RELATED TO OUTMIGRATION
Habitat Availabil ity.The outmigration of pink salmon fry almost immediately
__-after emergence results in little habitat utilization.Thus,surface area
response curves are not applicable to the evaluation of the pink salmon fry.
IV-3~
"""
"""
-
,....,
-
"...
-
-
Rainbow Trout
Adults
The size of the adult population of rainbow trout in the middle Susitna River
was approximated as 4,000 fish using 1981-1983 data (Schmidt et al.1984).
(Sundet and Wenger 1984).Wi th in th is reach of ri ver,recaptures of tagged
fish have been sufficient to estimate the population size of rainbow trout in
only one tri butary,.Fourth of July Creek where Sundet and Wenger (1984)
reported a population of approximately 100 rainbow trout.In 1983,
approximately 10 rainbow trout were estimated to reside in Fourth of July
Creek (between TRM 0.0 and 0.8,below the falls).The size of the population
in the middle Susitna River is relatively sman.The main reason for the low
population is probably due to the lack of spawning areas (Schmidt et al.
1984).Also,survival rates are relatively low especially in the wintertime
due to a lack of suitable overwintering habitat.The sport fishing pressure
at tributary mouths in the fall also contributes to the low population of
rainbow trout (ADF&G 1983c,Schmidt et al.1984).
Habitat Utilization.The distribution-ofaclult rainbow trout were grouped
into major categories according to season and life history activity.These
categories were spawning,rearing,transition,and overwintering (Sundet and
Pecheck 1985).The distribution of rainbow trout in 1983 and 1984 was very
similar (Schmidt et al.1984,1985).Rainbow trout occupy either the
tributaries or mainstem during May through October 1983 (Figure IV-19).
Spawning occurs primarily in tributaries during-May and -June--(Flgure IV-20).
Spawning sites occur in Whiskers Creek,lane Creek,and Fourth of July Creek.
The highest catches were -j n Fourth of July Creek (Sundet and Wenger 1984).
less important spawning si tes,in terms of a.bundance,incl uded Jndi an River
and Portage Creek.
Rainbow trout spawning in the middle Susitna River apparently occurs primarily
in tributaries with connecting lakes.These tributary lake systems are within
the Portage Creek drainage at TRM 2.3 and 5.21 and in the Fourth of July Creek
drainage at TRM 0.7.There is little evidence of spawning in Indian River
IV-40
I ~~,.--~01 )))01 )1 )j i })
2
..........,~---,........I_I.,:Iie 1_'., _ ,1-'.....a.,.-..
..·.·.·.·,·,·.
J\f ~
/V 'x~f\\
\{;"\~.~,,
I '/~I \[~r-,/."I ~"\/.':'"I"\.."..•"'\.o ;"ft •.¥,•.. .
;,
7
~
8
10
!8
15 5
Gl~...:z.....'\
.:1 1 ~\...'./'
,
I
_".:'/'0 ~_.-~_/'"
........tUN .tUN .,MJL JUL AUG AUO MP UP'ocrr1.-H 1_'.,.-~I-I.,a-MI'1-1.''-_,-'.,a-.'-I.
200..,,,,180···,·180···,
,~140···:·~120···u··§,·~100···15··!~80
,~..:z
60
.40
20 I -'.-
."..-
-....
."..-'\.
."..-,•I 0
,
".,,., ,,,,,.,,,,.,,,,.,.,,,
,,,,,,",",,\
~.~
__I.A ....INSTEI.A
•••••TRIBUT....RY
__SI.OUGH
.',
II·"
••••••III~...
'\.
'\.
.........
"-.
YAV ......~oIUL..NL ~AU4I ...~00f,.-M t_t.,.-aD t_t,,e-ao 1_1.,..._1_'.,.-ao ,-t.
20
11S
16
14
~~12
H @5
<D<Z~10I15ollo
~Iii IS
~z
8
4
2
0
Source:Suchanek et .1.1985
Figure IV-19.Boat electrof1sh1ng catch of rainbow trout,Arctic,grayling,
and burbot in major habitat types in the middle Sus1tna River,
1983.
"....
-
-
.....
TRANSITION PERIOD BETWEEN FALL AND WINTER
(OCTOBER-NOVEMBER)n-61
LOCATIONS IN
TRIBUTARIES
OR SLOUGHS
Source:Sundet and Pechek 1985 •.
Figure IV-20.Frequency distribution of radio-tagged rainbow trout locations
in the Susitna River during 1984 .
IV-42
-
-
,.,..,
.-
....,
-
although several lakes occur within Indian River drainage.It was suggested
that few fish spawn in Indian River because its location borders the northern
1imits of the rainbow trout range and fi sh passage to 1akes in the drainage
may be too difficult (Sundet and Pechek,1985).The timing of spawning in
.both portage Creek and Fourth of July Creek was in early to mid June (Sundet
and Pechek 1985).
Adult ra"inbow trout rearing occurs July throu!gh September primarily in natal
~ributaries or sloughs (Figure IV-20)(Sundet and Pechek 1985).The highest
catches of rainbow trout were in late July with relatively high catches also
occurring during early and late September.
Different movement patterns were noted within the rearing areas.In Fourth of
July Creek,most of the fish stayed between TR~1 0.4 and 1.8,while the rest of
the adults moved to the mouth,nearby sloughs,or into Indian River.In
Portage Creek,rainbow trout moved upstream after spawning.Many of the
rainbow trout that moved"into tributaries to spawn,remained in the same
tributary throughout the summer.Rainbow trout were found rearing in sloughs
9,8A,A,and Moose Slough during July and September (Sundet and Pecheck
1985).Lakes in the Portage Creek and Fourth of July Creek drainages are
thought to be important rearing areas for adults (Schmidt et al.1985).
The transition period of rainbow trout movements from rearing to overwintering
occurs from October to November (Figure IV-I0).Rainbow trout left the mouths
of tributaries and moved to the mainstem habitats.Documented mainstem sites
during the transition period included RM 137.3,138.3,147.1, 148.0,and
150.1.Monitoring of rainbow trout movement showed that all the rainbow trout
had outmigrated by October 6 and then moved slightly downstream (0.1 to 4.0
miles)before holding in overwintering areas (ADF&G 1983c,1983f,Sundet and
Wenger 1984).Thus,by December most rainbow trout had moved to overwintering
areas (Sundet and Wegner 1984).
Overwintering rainbow trout were found primarily In the mainstem Susitna River
from December through April (Figure IV-20).'Documented mainstem areas
included RM 100.7, 101.1,111.4,114.5, 114.8, 116.5, 131.1, 137.3, 138.3,
147.0-148.0 and 150.1.It is not known why rainbow trout utilize the mainstem
IV-43
-
during winter.During the winter of 1981-1982,several tagged rainbow trout
were found holding near the tributaries Portage Creek and Fourth of July Creek
where they were tagged (Schmidt et al.1984).
Habitat Requirements.Spawning habitat measurements were taken in Portage
Creek,east bank of Portage Creek,Fourth of July Creek,and a tri butary of
Fourth of July Creek (TRM 0.7)(Schmidt et al.1985).Habitat characteristics
included depths ranging from 1.4 to 4.5 ft,velocities ranging from 0.2 to
2.5 fps,and substrate sizes ranging primarily from small gravel to large
cobble.
Temperature probably influences the migration of rainbow trout to spawning
areas.The movement of adult fish into the trib~taries in late May occurred
at water temperatures of 6.lOC to 8.SoC.It is suspected that spawni ng
probably occurs in lake outlets where water temperatures are warmer.Water
,temperatures of the outl ets of several 1akes within the Fourth of July Creek
and Portage Creek drainages were 12 0 C in June (Sundet and Pechek 1985) .
.Rainbow trout suitability criteria for rearing adults were developed using
depth,velocity,cover type,and percent cover (Figures IV-21 and IV-22).
Typical habitats included the following characteristics (Suchanek et ale
1984).Fish caught by electrofishing preferred water depths of 4.5 to 6.5 ft
and water velocities less than 1.5 fps.Preferred cover types were rocks with
diameters greater than 3 inches followed by debris and overhanging riparian
vegetation.Rainbow trout caught with hook and line were found in depths
greater than 2 ft and in velocities less than 0.5 fps.Rainbow trout used
debri s,banks,and vegetation more for cover than the 1arger substrates.
Adult rainbow trout were also found to avoid turbid water (Suchanek et ale
1984).
Rainbow trout suitability indices (for depth,velocity,and substrate)in the
middle Susitna River were similar to sUitability indices described by Raleigh
et ale (1984).Water depths ranged from 0 to 10 ft with preferred depths
between 0.8 and 1.6 ft.Water vel oci ties ranged from 0.0 to 3.00 fps wi th
preferred velocities at 0.00 fps.Substrate types ranged from detritus to
boulders with preferred substrates 2.5 to 9.8 inches in diameter.
IV-44
J i 1 1 ))1 1 1 j -)]1 ))]
1.25-.N~2'
N=IO 1.00~1 RAINBOW TROUT
·.£Il)1 .,..BOAT ELECTROFISHINGI:!:S'ClndCl,d E,rlll'
,
:J 0.75 1.00•N-16N~4 ~'it;,,..;0-7lJN=I04 0.50 -LN-40 0.50
0.25~~_I -..,~~,','"'.0.25-~~,~•.\&''.~ii y •".'..I''..'nk;;iIs::.L:::....~;1 "'0.25.,-:>..,~.,.','.'.,....,.-'b
0
0
o '
,-"4;_~____',.1,'~.,_·,~·,.~,t~JW;,:;;1f1 o I'i 51"i r i i ~.wf[f·'¥'1f;\'!;~o'?-;!<.."H P ,""-, 0 en0I I 4-i'Ii·c:
a:1.0 2.0 3.0 4.0 aD 6.0 0.5 1.0 I.a 2.0 2.0 3.0 5.0 4.0 4.5 =i
bI DEPTH (ftl VELOCITY <ft/••c)•L CD
:I:C
U -t
H tc -<<:N-'O IIU
1 z
~Z 1.00 1.00 0
VI C N~54 rr'I
bI N=46
T
)(
2 0.75 T 0.75 N=28-~1.00".
0.50-1 I I I T I:t;I elitl 0.50....-a.....I'!~I 1-0.7lJ
i;~~~~,::I 1-0.!l0
025-1 "~AA I·{'".'.:H 1/I 1%1 1:t1~1 0.2501 T I~I Ij~i1i,;;wl'":~lJI "'0.25
*.t
o 'r ,r "'P-"1"-"1 rp~'··ar'l o I I '",,r ....,I'l'o.
j I ,r I ' 0j
0""S%6"'28%26-00%51·%NO EMEIl DEBRIS (IR.RU ..CO"
COVER OR OR 1-3 3-5 ..5
AQUATIC RIPARIAN
VEG.VEG.
PERCENT COVER COVER TYPE
Source:Suchanek et al.1985
Figure IV-ZI.Depth,velocity,and cover habitat requirements for rainbow
trout captured by electrofishing in the middle Susitna River.
}).~J )...)-1 .---1 -1 1 J -J 1 J )J
Figure IV-22.Depth,velocity,and cover habitat requirements for rainbow
trout captured by hook and line in the middle Susitna River.
Wi nter habitat measurements were scarce due to the di fficul ty of sampl i ng.
Habitat characteristics associated with the mainstem overwintering sites
included:depths ranging from 1.0 to 10.0 ft,velocities of 0.0 to 2.5 fps,
and substrate composed predominantly of rubble and cobble (3 to 10 inches in
diameter).Water temperatures ranged from 0 to O.l oC.The rainbow trout were
probably associated with groundwater upwelling as conductivity ranged from 212
to 256 umhos/cm.Most of these mainstem areas:had open water 1eads (Schmidt
et al.1985,AFD&G 1983c).
Rainbow trout movements were strongly influenced by the timing and location of
a particular food source.Salmon eggs,when available,are a major food
source for rainbow trout.In July,rainbow trout moved to areas of chinook
spawning in Indian River and Portage Creek.Later in August they moved to
areas of pink and chum spawning (Barrett et al.1984,Sundet and Wegner 1984).
The rainbow trout were found in shallower water when feeding on salmon eggs
and deeper water when feeding on insects (Suchanek et al.1984).
~Habitat Availability.(will be provided later)
Juveniles
Catches of juvenile rainbow trout from 1981 to 1983 have been low.Sundet and
Wegner (1984)suggested that either reproduction was limiting or survival was
low (ADF&G 1981,1983a).However,during 1984,336 juvenile rainbow trout
were captured in 1akes connected to Fourth of July Creek and Portage Creek,
indicating that reproduction and survival appears to be higher in tributary
1ake systems.
Habitat Utilization.Juvenile rainbow trout iikely rear mainly in lakes
connected to the tri butari es or in the upper reaches of Portage Creek and
Fourth of July Creek (Sundet and Pecheck 1985<).One of the few tri butaries
that was found to support a juvenile rainbow trout population was Fourth of
July Creek.As mentioned above,Fourth of JUlY Creek appears to providerbetterrainbowtrouthabitatbecauseoflakeswithinthedrainage(Sundet and
Wenger 1984).There is also a limited amount of rearing in mainstem and
slough habitats of the Susitna River (ADF&G 1983a,Schmidt et al.1984).
IV-47
.....,.........,~I""""""--_-----------.......'!""~--------------r-'--
-
Habitat Requirements.Suitability indices for juvenile rainbow trout in the
middle Susitna River have not been developed.However,suitability indices
have been developed by Raliegh et al.(1984).Results of the analyses
performed by Raliegh et-al.indicate the juvenile rainbow trout utilize water
depths of 0.2 to 10 ft with preferred depths between 2.0 and 10.0 ft.Water
velocities ranged from 1.0 to 3.0 fps with preferred velocities from 0.00 to
0.49,and substrate types ranged from detritus to boulders with preferred
substrates around 9 inches in diameter.
(Habitat Availability.(will be provided later)
L;;?>··
IV-48
r
I
!
Arctic Grayling
Adults
The abundance of Arctic grayling in the midd1e Susitna Riv~r was simliar in
1982 and 1983 (Sundet and Pechek 1985).The Arctic grayling is estimated to
-be the third most abundant resident fish in the middle river (not counting
sticklebacks or sculpins).Only longnose sucker and round whitefish are more
abundant.In 1982,the population was estimated to be between 4,783 and
28,192 fish and in 1983,the population was estimated to be between 4,070 and
15,152 fish.Population estimates in 1981 and 1984 were not made (Sundet and
Pecheck 1985).
Habitat Utilization.Grayling exhibit strong seasonal migration patterns.
Grayling moved from the mainstem of the middle Susitna River into the
tributaries to spawn.This migration occurred during May and early June,
,,~before and immediately after the breakup of river ice (ADF&G 1983a,1981,
Sundet and Wenger 1984).The tri butari es used for spawni ng duri ng 1981 to
1984 include Indian River,Portage Creek,Whiskers Creek,Lane Creek and
Fourth of July Creek.After spawning fish may remain in spawning areas or
migrate further up the tributary to summer feedling areas.
The timing of spawning varies in different parts of the middle river.
Grayling in tributaries below RM 125 spawned about 7-10 days earlier in May
than fish above RM 125.This may have been due to warmer water temperatures
in tributaries below RM 125 (Sundet and Pechek 1985).
During summer,grayling are abundant in tributaries.Tributaries of
importance include those listed for spawning in 1981 to 1984.In addition,
Jack Long Creek has been utilized by grayling,but not extensively (Sundet and
Wenger 1984,Sundet and Pechek 1985).Gray11ing have been captured at the
following mainstem areas:RM 137.3 to 138.3,RM 147 to 148 and RM 150.1.The
mainstem at RM 150.1 has had the most abundant mainstem catches.
In August and September,fish move out of the tributaries and into therrnainstemforoverwinteringduringOctobertoApr;1.A1most a11 grayl i ng move
'I
IV-49
....,,,j -
......
,.-
i
out of the tributaries into the mainstem by the end of September in 1983
(Sundet and Wenger 1984).
There is little known about the winter distribution of grayling in the
mainstem.Besides mainstem overwintering,Portage Creek is thought to provide
winter habitat.Portage Creek is characterized by many deep (20 ft)pools to
harbor fish.Recent recapture data showed that overwintering may occur in the
mainstem between RM 146.0 and RM 148.0,at RM X50.1,and downriver from summer
tributaries (Sundet and Pechek 1985).
Habitat Requirements.There is little specific information on grayling
spawning habitat in the middle Susitna River.In Krueger's (1981)summary of
spawning habitat,fish spawned in areas with water depths varying-from 0.18 to
3 ft,surface current velocities of 0.8 to 3.9 fps,and in unimbedded small
gravels.
·".In general adults were found mainly in t.ributaries or mainstem areas
.throughout the year (Suchanek et ale 1984).Grayl ing util ized water depths
-~.ranging from 0.0 to 6.5 ft water velocities ranging from 0 to 4.3 fps,and
substrate'sizes ranging from 3 to 5 in.in diameter (Figure IV-Z3).Turbid
areas were avoided (Suchanek et ale 1984).
.Wi nter habi tat requi rements of Arctic gray};ng in the mi ddl e Sus itna Ri ver
have not been measured.However,winter hab'itat measurements taken near a
radio-tagged grayling in the lower river included a water depth of 2.3 ft,a
water velocity of 0.3 fps and a substrate size of 1 to 5 inches in diameter.
Habitat preferences for grayl ing in the Susitna River are silllil ar to other
studies.Hunter (1973 )found grayling utilized water depths greater than
0.4 ft and substrate sizes between 0.1 to 6.0 inches in diameter.DenBeste
and McCart (1984)found grayl i ng preferred water depths of 1.9 ft,water
velocities of 0.0 fps,and substrates less than 0.1 inches in diameter.
Habitat Availability.(will be provided later)
IV-50
'---',1 }~---,--t J 1 })
...,..-24 J,ARCTIC GRAYLING
1 I
"-110 i~~~~~:C:'~~FISHING
1.0 a.ouul ~N-40
2.0
I I I
1.00
i •'.""1""'."1 )~..~..~..."ff.·.···.··.I··.•···.".'..,.•......'\11".'.i~~····'.$·I.·J·::.';'.·.;.J\Lo.n
1.0 ' ,~.'.'10 ..'",.~\)\'"
...;.L "•~08 •.':.:'.~~_\.~0.80.---~...__.',..
::0.'_.-0.25
§0 0 00
-10 20 10 4.0 8,0 6.0 0.6 1.0 US 2.0 2.0 3.0 3.0 4.0 4.0 ~
~DEPTH (tt)VELOCITY Ctt I ••c))0
~!
H ~
<fi ~
I ~i -eU1iC
.....U "I 2.a ZzM40~•..1 NT"'l.G Tic
:II 1 ....'.'1 N-Ie 1.00
0.15
1.0-1 II....I '....I I I I 1.0
0.00
,..-32 '..ii,>..,~-L I,I -L.,I 0.'N~'~0.2'
N-87 N-ta
0',~""'1 I r 'i"0',7 1 ,',,1 iii:",,''0
0-15"110 s-U"IIo 28-eo'Ye 51+"110 NO EMER.DEBRIS GR.RU..cg,
COVER OR OR 1-S 3-15 ·15
AQUATIC RIPARIAN
YEG.VEG.
PERCENT COVER COVER TYPE Source:Suchanek et a1.1985
Figure IV-23.Depth,velocity,and cover habitat requirements for Arctic
grayling captured by electrofishing in the middle Susitna
River.
Juveniles
-Few juvenile Arctic grayling have been captured in the middle Susitna River.
In 1983,21 juveniles were captured,20 Wl9re captured in mainstem side
channels and one was captured in a tributary (Suchanek et al.1984).
Habitat Utilization.Juvenile Arctic grayling exhibit a migration patt~rn
similar to adult Arctic grayling.In the summer juveniles remained in
tributaries or moved to tributary mouths until September.Juveniles (age
class 2 to 4)were also captured in the mainstem during the summer.These
fish may have been displaced by older,larger'fish defending more favorable
tributary habitat.Juveniles have also been found in the mixing zones of
sloughs,tributaries or mainstem waters (ADF&G 1983a).
Begi nni ng in September,the juveni 1es moved into the mai nstem of the middle
river to overwinter (ADF&G 1983a,Schmidt et al.1984).Juvenile rainbow
trout either move from the spawning area with the adult rainbow trout or
shortly thereafter.Decreased water temperatures,di scharge,and food avai l-
ability probably influence the timing of migration (Krueger 1981).Specific
overwintering areas for juvenile Arctic grayling have not been identified.
Habitat Requirements.Juvenile Arctic grayling showed habitat preferences for
depths of 1.9 ft,water velocities of 0.0 fps and substrates less than 0.08
inches in diameter (Krueger 1981).Juvenile arctic grayl ing «200 mm)may
have microhabitat preferences similar to chinook salmon fry (Suchanek et al.
1984).In the upper Chena River,near Fairbanks,Alaska,juvenile Arctic
grayling habitat preferences were similar to Susitna River juveniles.Arctic
grayling juveniles were most abundant in water depths of 1.0 to 1.5 ft,in
water velocities of 0.0 fps,and in silty substrate areas (Lee 1985).
Juvenile grayling are opportunistic feeders.,Younger juveniles feed on
smaller food items such as zooplankton and the older juveniles feed on
immature insects (Krueger 1981).The juveniles probably hold in areas of1lowercurrentvelocitiesthenmovetofasteranddeeperareasforincreased
food availability and cover.
IV-52
-
T
I
A suitability index was developed for Arctic grayling using turbidity.Arctic
grayling tended to avoid turbid water (Suchanek et ale 1984).Turbidity
becomes more important when juvenile Arctic grayling are displaced to mainstem
areas by the older Arctic grayling.In the mainstem,turbidity substitutes as
,cover for Arctic grayling (Suchanek et ale 1984).
Habitat Availability.(will be provided later)
IV-53
.,--
-
-
-i
I
...<,
i
I,
Burbot
Adults
Burbot are found in the middle Susitna River,but are not abundant (Suchanek
et al.1984,Sundet and Wegner 1984,Sundet and Pechek 1985).In 198~
burbot were captured in the middle river.A population estimate of 15 burbot
(confidence interval 13 to 24)was made for the site at RM 138.9-140.0 in 1983
(Schmidt et al.1984).The small number of burbot in the middle Susitna River
have been attributed to several factors including the scarcity of food and
rearing habitat.
Habi tat Uti 1i zat ion.The burbot 1i ves a sedentary 1 ife,except for movement
to and from the spawning areas (Morrow 1980).Most movement is thought to
take place in December,when the burbot migrate to the spawning grounds and in
March when the burbot leave the grounds (Morrow 1980).The spawning locations
of burbot spawning areas in the middle river are believed to be located in
.mouths of sloughs and tributaries,and in deep backwater areas influenced by
groundwater upwell ing (Sundet and Wenger 1984,ADF&G 1983e).Ouri ng 1983,
burbot were found in mai nstem,sloughs,and tri butary mouths from May to
October (Suchanek et al.1984).During 1984,78 percent of the burbot were
captured in mainstem Susitna sites at RM 102.5,and 147.0-148.0,and at a side
channel site at RM 139.6.
Habitat Requirements.Burbot spawn in the winter from November to February
(ADF&G 1981b,-1983a).-Burbot -spawning occurs under the ice,in water
temperatures between 0.6 to 1.70 C,in water depths of 1 to 4 ft,and on
substrates of sand or gravel (Morrow 1980).The water temperatures observed
at the Susitna River mainstem spawning areas below RM 98.6 were between 0 and
0.70 C (Meyer et al.1984).
Some habitat preferences of burbot in the middle Susitna River have been
observed.Burbot occupy the turbid waters of the mainstem most of the year.
Burbot usually avoid clearwater (Sundet and Wenger 1984,Mecum 1984).Catch
data (1981-1983)showed burbot preferring low velocity waters of less than
IV-54
-
-I
-
1.5 fps,shallow water depths around 2.5 ft,and a rubble or cobble substrate
(ADF&G 1981b,ADF&G 1983a,ADF&G 1983e,Suchanek et ale 1984).In the Tanana
River,burbot were seldom caught in water depths less than 1.5 ft (Mecum
1984).Habitat measurements were taken in the middle Susitna River during
December 1983 near a radio-tagged burbot located at RM 131.1.The site had a
depth of 4 ft,a velocity of 1 to 2 fps,and a water temperature of 0.2oe.
The food preferences of Sus itna bUY;'bot have not been determi ned (Sundet and
Wenger 1984).There have been a few burbot captured near sal man spawn i ng
sites that ingested salmon eggs.However,ingE!stion of eggs was thought to be
low.Morrow (1980)states that burbot have a strong preference for fi sh
rather than eggs or insects.
Habitat Availability.The amount of available habitat for spawning may be a
limiting factor to the middle Susitna River burbot population (Sundet and
Pechek 1985).
.....Juvenil es
There have been few juvenile burbot captured .in the middle Susitna River.In
1983,only 18 juvenile burbot were captured at the juvenile anadromous habitat
sites in the middle Susitna River.And in 1982,only 22 juvenile burbot were
captured in the mainstem of the middle Susitna River.
'Habitat Utilization.It is suspected that juveniles rear in the mainstem,
tributary mouths,slough mouths and clear water sloughs (ADF&G 1981,1983a)
and seek areas of upwell i ng (ADF&G 1983b).Burbot juven i1es we-re captured
near Slough 9 in 1982 (ADF&G 1983a).
Habitat Requirements.(will be provided later)-Habitat Availability.(will be provided later)
-
IV-55
-
r
i
Doll y Varden
Adults
Dolly Varden catches throughout the Susitna River have been low (Schmidt et
al.1984,Sundet and Pecheck 1985).In 1983,89 percent of the 47 Dolly
Varden caught in the Susitna River were upstream of Talkeetna.
Habitat Utilization.There is a Dolly Varden migration pattern similar to
Arctic grayling.Dolly Varden migrate from summer rearing and spawning areas
in tributaries to overwintering areas in the mainstem.Catch data suggested
that most Dolly Varden moved into the tributaries before 1 ate June (ADF&G
1983a,Schmidt et al.1984).The highest catches in the middle Susitna River
have occurred in lane Creek,Indian River,and Portage Creek (Schmidt et al.
1984,1985).The fish were then thought to remain in the tributaries until
mid-September to October (Sundet and Wenger 1984,Sundet and Pecheck 1985).
In the fall after spawning,there was a migration back to the mainstem.
There was a popul at i on of dwarf Dolly Varden found in the upper reaches of
several tributaries.These fish are thought to remain throughout the year in
tributaries such as Indian River and Portage Creek (ADF&G 1983).
Habitat Requirements.Habitat requirements for Dolly Varden in the middle
Susitna River have not been quantified.However,habitat requirements are
avail abl e for Dolly Varden from other studies done in Al aska (81 ackett and
"Armstrong 1965,Wilson et al.1981).Dolly Varden in southeast Alaska spawned
in depths from 0.1 to 3.8 ft;and in ri ffl e/run and pool reaches in water
velocities of 1.0 to 3.8 fps.The gravel was usually small at 0.02 to
2.00 in.in diameter (Blackett and Armstron~J 1965).Habitat SUitability
curves done for spawni ng Dolly Varden in the Terror Lake drai nage on Kodi ak
Island showed similar preferences with water depths between 0.8 to 4.2 ft,
water velocities of 0.9 to 2.5 fps,and substrate sizes ranging from 0.08 to
2.5 in.in diameter (Wilson et al.1981).
IV-56
-
Distribution of adult Dolly Varden has been dilrect1y linked with food sources.
Thus,Dolly Varden are found near salmon spawning areas when salmon eggs and
fry are available (Blackett and Armstrong 1965).Dolly Varden are also known
to feed on invertebrates such as Chaeoborus,ch i ronomi ds,and Daphn ia (Hume
and Northcote 1985).
Habitat Availability.(will be provided later)
Juveniles
There have been so few juvenile Dolly Varden captured in the middle Susitna
River that estimation of relative abundance has not been possible.
Habitat Utilization.Habitat utilization of juvenile Dolly Varden in the
middle Susitna River are unknown.It is thought that the juveniles rear in
the upper reaches of tributaries during the summer and then migrate to the
mainstem in the fall to overwinter (Schmidt et al.1984).
Habitat Requirements.General descriptions of juvenile Dolly Varden habitat
on Kodiak Island and southeast Alaska are available.After emergence,
juveniles occupied shallow areas in tributaries with low water velocities and
varying sizes of substrates (Blackett 1968,Armstrong and Elliot 1972).These
slower velocity areas were utilized until the fish grew large enough to move
into faster currents to feed on drifting invertebrates.Juvenile Dolly Varden
in Kodiak al so seemed to prefer the slower velocity waters and the warmer
waters of eddies,pools,side channels,and sloughs (Wilson et al.1981).
Suitability criteria in the Terror Lake drainage showed that juveniles
-preferred depths of 0.1 to 1.0 ft,and water velocities of 0.0-0.2 fps.No
preference for substrate sizes was observed.
Temperature is thought to i nf1 uence m;grat i on (Krueger 1981).Mi grat i on to
overwintering areas occurred at temperatures between 7 and 40 C.Winter water
temperatures are usually around 10 C (Elliot and Reed 1974,1975).When water
temperatures rose above 2°C,Dolly Varden fry came out of the gravel and swam
about the stream.Cover such as debris,large substrates,and a stable winter
flow are probably important to winter survival (Ell iot and Reed 1974,Ell iot
IV-57
-
-
.....
-
....
-
1975).Migration from the overwintering sites to summer rearing occurred when
temperatures rose from l oC to 4 or SoC.
Food preferences of juveni 1es vari ed wi th the season.From Apri 1 to June
immature insects were preferred,while from July until November salmon eggs
and small salmon were preferred (Krueger 1981).
Habitat Availability.(will be provided later)
IV-58
-
....
Will be provided later.
V.SUMMARY
V-I
-
-
VI.LITERATURE CITED
Aaserude,R.G.,J.Thiele,and D.Trudgen.1985.Characterization of aquatic
habitats in the Talkeetna-to-Devil Canyon segment of the Susitna River,
Alaska.Prel im"inary draft report •.E.Woody Trihey and Associates and
Arctic Environmental Information and Data Center,University of Alaska,
Fairbanks.Alaska Power Authority.Susitna Hydroelectric Project.
1 vol.
Alaska Department of Fish and Game,Susitna Hydro Aquatic Studies.1981a.
Phase I Final Draft Report.Adult anadromous fisheries project.Pre-
pared for Acres American,Inc.Buffalo,NY.
___•1981b.Phase I Final Draft Report.Juvenile anadromous fish study
on the lower Susitna River.Prepared for Acres American,Inc.Buffalo,
NY.
-,
""'"i
___1981c.Phase I final draft report.
investigation on the lower Susitna River.
Game.Anchorage,Alaska.
Subtask 7.10.Resident fish
Alaska Department of Fish and
,....1982.Phase II Final Data Report:Volume 2.Adult anadromous fish
studies.Anchorage,Alaska.
1983a.Phase II Basic Data Report.Volume 3:
anadromous fish studies below Devil Canyon,1982.
Resident and juvenile
Anchorage,Alaska.
1983b.Phase II Basic Data Report:Summarization of Volumes 2,3,
4;Parts I and II,and 5 -Su Hydro Basic Data Reports,1982.Anchorage,
Alaska.
1983c.Phase II Data Report:Winter aquatic studies (October,1982
-May 1983).Anchorage,Alaska.
1983d.Use of major habitat types by juveni 1e salmon and resi dent
species.Appendix G in Susitna Hydro Aquatic Studies Phase II Report,
VI-1
-
.-
synopsis of the 1982 aquatic studies and analysis of fish and habitat
relationships (2 parts).Alaska Department of Fish and Game.Anchorage,
Alaska.
___1983e.Phase II Data Report.Winter aquatic studies (Oct.1982 -
May 1983).Alaska Department of Fish and Game •.Anchorage,Alaska.
___1983f.Aquatic studies procedures manual (1982-1983).Phase II.
Subtask 7.10.Alaska Department of Fish and Game.Anchorage,Alaska •
_____1983g.Aquatic habitat and instream flow investigations (May-October
1983).Chapter 4:Water Quality Investigations.Report No.3 Alaska
Department of Fish and Game.Anchorage,Alaska.
1983h.Phase II basic data report.Vol.4:Aquatic habitat and
instream flow studies,1982.Parts I and II..Anchorage,Alaska.
1984.Susitna Hydro Aquatic Studies,Report No.
juvenile anadromous fish investigations,May -October
Alaska Power Authority,Anchorage,AK.395 pp.
2:
1983.
Resi dent and
Report for
1985.Resident and juvenile
October 1984.Report No.7.
Anchorage,Alaska.
anadromous fish investigations:May-
Alaska Department of Fish and Game,
Alaska Power Authority.1985.Amendment to the application for license for
major project,Susitna Hydroelectric Project,before the Federal Energy
Regulatory Commission.Draft.Exhibit E,Chaps.2 and 3.Alaska Power
--Il\uthority.Susitna Hydroelectric Project.Vols.6,7,8 and 9.
Alderdice,D.F.,and F.P.J.Velsen.1978.Relation between temperature and
incubation time for eggs of chinook salmon (Oncorhynchus tshawytscha).
J.Fish.Res.Bd.Can.36:69-75.
-VI-2
-
-
"...
[
i
,W.P.Wickett,and J.R.Brett.1958.Some effects of temporary----
exposure to low dissolved oxygen levels on Pacific salmon eggs.J.Fish.
Res.Bd.Can.15:229-250.
Arctiic Environmental Information and Data Center.1984.Assessment of the
effects of the proposed Susitna hydroelectric project on instream temper-
ature and fish resources in the Watana to Talkeetna reach.Alaska Power
Authority.
Armstrong,R.and S.Elliott.1972.A study of Dolly Varden in Alaska.
Alaska Department of Fish and Game.Federal Aid in Fish Restoration,
Annual Progress Report,1971-1972.Project F-9-4-13:1-14.
Armstrong,R.H.1982.Arctic grayling studies in Alaska.Alaska Cooperative
Fishery Research Unit,University of Alaska,Fairbanks,Alaska.
Barre~tt,B.M.,F.M.Thompson, and S.N.Wick.1984.Susitna Aquatic Studies
Program Report No.6.Adult anadromous fish investigations.May-
October 1984.Alaska Department of Fish and Game.Anchorage,Alaska.
Barrett,B.M.,F.M.Thompson,and S.N.Wick.1985.Susitna Aquatic Studies
Program.Report No.6.Adult salmon investigations.May -October
1984.Alaska Dept.of Fish and Game.Anchorage,Alaska.
Baldrige,J.E.and E.W.Trihey.1982.Potential effects of two alternative
hydroelectric developments on the fishery resources of the lower Tazimina
River,Alaska.Alaska Environmental Information and Data Center,
Anchorage,Alaska.
Barns,R.A.1967.A review of the literature on the effects of changes in
temperature regime on developing sockeye salmon eggs and alevins.J.
Fish.Res.Bd.Can.,M.S.949:14-22.
Bailey,J.E.,and D.R.Evans.1971.
salmon eggs in relation to
Fisheries Bulletin 69:587-593.
The low-temperature threshold for pink
a proposed hydroelectric installatinn.
VI-3
-
-
-
-
Beck.~r,C.D.1970.Feeding bionomics of juvenile chinook salmon in the
central Columbia River.Northwest Science.44(2):75-81.
Becker,C.D.,O.A.Neitzel and D.H.Fickeisen.·1982.Effects of dewatering
on chinook salmon redds:tolerance of four developmental phases to daily
dewaterings.Trans.Am.Fish.Soc.111:624-637.
Bell,M.C.1973.Fisheries handbook of engineering requirements and biologi-
cal criteria.Useful factors in life history of most common species.
U.S.Army Corp.Fish-Engineering.North Pac.Div.,Portland,Oregon.
Binns,N.A.,and F.M.Eiserman.1979.Quantification of fluvial trout
habitat in Wyoming.Trans.Am.Fish Soc.108:215-228.
Bjornn,T.C.1971.Trout and salmon movements in two Idaho streams as
related to temperature,food,stream flow,cover,and population density.
Trans.Amer.Fish.Soc.100(3).
Blackett,R.and R.Armstrong.1965.Investigations of anadromous Dolly
Varden populations in the Lake Eva-Hanus Bay drainages,southeastern
Alaska.Alaska Department of Fish and Game.Federal Aid in Fish Resto-
ration,Annual Progress Report,1964-1965.Project K-5-R-6:23-56.
Blackett,R.1968.Spawning behavior,fecundity,and early life history of
anadromous Dolly Varden,Salvelinus malma (Walbaum)in southeastern
Alaska.Alaska Department of Fish and Game,Research Report 6:1-85.
Blakely,J.S.,J.S.Sautner,L.A.Rundquist,N.E.Bradley.1985.Addendum to
Alaska Dept.of Fish and Game.Report No.3,Chapter 6:Salmon Passage
Validation Studies.August -October 1984.
Bovee,K.D.1978.Probability-of-use criteria for the family Salmonidae.
Instream Flow Information Paper.No.4.u.S.Fish and Wildlife Service.
FWS/635-82/26.
VI-4
Brannon,E.l.1965.The influence of physical factors on the development and
weight of sockeye salmon embryos and alevins.Intern~tional Pacific
"'-
Salmon Fisheries Commission,New Westminster,Canada.
Brett,J.R.1952.Temperature tolerance in young Pacific salmon,genus
Oncorhynchus species.J.Fish.Res.Bd.Can.9:265-323.
Burger,C.V.,D.B.Wangaard,R.L.Wilmot,and A.Palmisano.
Investigations in the Kenai River,Alaska.1979-198l.
Wildlife Service;Anchorage,Alaska.
1983.Salmon
u.S.Fish and
.....
-
Burns,J.W.1971.The carrying capacity for juvenile salmonids in some
northern California streams.California Fish and Game.57(1):24-57.
Bustard,D.R.,and D.W.Narver.1975.Preferences of juvenile coho salmon
(Oncorhynchus kisutch)and cutthroat trout (Salmo clarki)relative to
simulated alteration of winter habitat.J.Fish.Res.Bd.Can.
32:681-687.
Cede,"holdm,C.J.,L.M.lewis and E.O.Salo.1981.Cumulative effects of
logging road sediment on salmonid populations in the Clearwater River,
Jefferson County,Washington.Pages 38-74 l!!.State of Washington Water
Research Center,editor.Salmon-spawning gravel:a renewable resource
in the Pacific Northwest?Report 39,State of Washington Water Research
Center,Washington State University,Pullman,Washington,USA.
_____,and W.J.Scarlett.1982.Seasonal immigrations of juvenile salmonids
into four small tributaries of the Clearwater River,Washington
1977-1981.Pages 98-100 in E.l.Brannon and E.O.Salo,eds.Proceedings
of the Salmon and Trout Migratory Behavior Symposium.School of
Fisheries,University of Washington,Seattle,WA.
Chambers,J.Se,G.H.Allen,R.T.Pressey.
of spawning grounds in natural areas.
of Fisheries.
VI-5
1955.Research relating to study
Olympia,Washington.State Dept.
-___R.I.Pressey,J.R.Donaldson,and W.R.McKinley.1954.Research
relating to study of spawning grounds in natural areas.Olympia,
~
Washington,State Dept.of Fisheries.
Chapman,D.W.,and I.C.Bjornn.1969.Distribution of salmonids in streams
with special reference to food and feeding.Pages 153-176 in T.G.
Northcote:.ed.Symposium on salmon and trout in streams.H.R.MacMillan
Lectures in Fisheries,University of British Columbia,Vancouver,Canada.
Clay,C.H.1961.Design of fishways and other fish facilities.Can.Dept.
Fish.Ottawa,Canada.
Collings,M.R.1974.Generalization of spawning and rearing discharges for-several Pacific salmon species in western Washington.U.S.Geol.Surv.
open file report.
"""
Combs,B.D.1965.Effects of temperature on the development of salmon eggs.
Progressive Fish-Culturist 27:134-137.
-
Crumley,S.C.imd O.J.Stober.1984.Skagit River Intern Agreement Studies.
Volume 1.Instream flow fish habitat analysis.Final Report.Fisheries
Research Institute,University of Washington,Seattle,Washington.
Report No.FRI-VW-8406.
Cummins,K.W.1975.Macroinvertebrates.Pages 170-198 in B.Whitton,ed.
River ecology.Blackwell Scientific Publications,England.
Cunyak,R.A.,and J.M.Green.1983.Habitat utilization by brook char
(Salvelinus foninalis)and rainbow trout (S.gairdneri)in Newfoundland
streams.Can.J.Zool.61:1214-1219.
Daubll~,D.O.,R.H.
;zooplankton in
'1 n the central
Gray,and T.L.Page.1980.Importance of insects and
the diet of 0 age chinook salmon Oncorhynchus tshawytscha
Columbia River.Northwest Science.54(4):253-258.
VI-6
Dong:,J.N.
embryos.
-
-
-
-
Delisle,G.E.1962.Water velocities tolerated by spawning kokanee salmon.
Calif.Fish and Game.48:77-78.
DenBeste,J.,and P.McCart.1984.Results of studies of long-term effects
of the Trans Alaska Pipeline system on fish and aquatic habitats.
Volume II.Prepared for Alyeska Pipeline Service Company by Aquatic
Environments Incorporated.
1981.Thermal tolerance and rate of development of coho salmon
Master's Thesis.Univ.of Wash.Seattle,Washington.
Dugan,L.J.,D.A.Sterritt,and M.E.Stratton.1984.The distribution and
relative abundance of juvenile salmon in the Susitna River drainage above
the Chul itna River confluence.Report 2.Part 2.In:Resident and
juvenile anadromous fish investigations (May-October 1983).D.C.
Schmidt,S.S.Hale,D.L.Crawford,and P.M.Suchanek,eds.Susitna Hydro
Aquatic Studies.Alaska Department of Fish and Game,Anchorage,AK.
Egglishaw,H.J.1969.The distribution of benthic invertebrates on substrate
~in fast flowing streams.J.Anim.Ecol.38:19-33.
Elliott,S.1975.Ecology of rearing fish.Alaska Department of Fish and
Game.Federal Aid in Fish Restoration,Annual Progress Report,
1973-1974.Project 5-9-6 (D-I-B):9-43.
.A,
..-
Elliott,S.and R.Reed .
of Fi sh and Game.
Report,1973-1974 •
1974.Ecology of rearing fish.Alaska Department
Federal Aid in Fish Restoration,Annual Progress
Project 5-9-6 (D-I-B):9-43.
Estes,C.and K.Hepler.1981.Willow and Deception Creeks instream flow
demonstration study.Vol.1.Alaska Dept.of Fish and Game for USDA
Soil Cons.Service Basin Study Agreement #580436816.-Eo Woody Trihey and Associates and Entrix.
report.Volume 1.Working draft.
Hydroelectric Project.1 vol.
VI-7
1985.Instream flow relationships
Alaska Power Authority.Susitna
.-
Graybill t J.P q R.L.Burgner t J.C.Gislason t P.E.Huffman,K.H.Wyman t R.G.
Gibbons t K.W.Kurko,Q.J.Stober,T.W.Fagnan,A.P.Stayman t and D.M.
Eggers.1979.Assessment of the reservoir-related effects on the Skagit
Project on downstream fishery resources of the Skagit River t Washington.
Univ.of Wash.
Hale,.S.S.1984.Time series analysis of discharge t turbidity,and juvenile
salmon outmigration in the Susitna River t Alaska...!.!l:Resident and
juvenile anadromous fish investigations (May-October 1984).D.C.
Schmidt,S.S.Hale,D.L.Crawford t eds.Susitna River Aquatic Stud·ies
Program.Alaska Department of Fish and Game.Anchorage t Alaska.
Harza-Ebasco Susitna Joint Venture.1985.Instream flow relationships
report.A limnological perspective of potential water quality changes.
Draft report.Technical Report No.3.Alaska Power Authority.Susitna
Hydroelectric Project.
Hoffman t A.B.1985.Report No.9.Summary of salmon fishery data for
selected middle Susitna River sites.Susitna Hydro Aquatic Studies t
Alaska Dept.of Fish and Game.Report for Alaska Power Authority,
Anchorage,AK.1 vol •
Hoopes,D.1962.Ecological Distribution of spawning sockeye salmon in three
lateral strearns t Brooks Lake,Alaska.Ph.D.thesis.Iowa State Univ.of
Science &Technology.Ames,Iowa.USA.
Hunter t J.W.1973.A discussion of
related to water requirements.
Univ.Olympia,Wash.
game fish in the State of Washington as
Rep.by Fi sh Manage.Div.Wash.State
.-Hynes t H.B.N.1968 •
mountain stream.
Further studies on the invertebrate fauna of a Wel sh
Arch.Hydrobiol.65:360-379.
-
Jennings,T.R.1985.Susitna Hydroelectric Project Instrearn Flow Relation-
ships Report Series.Technical Report No.1.Fish Resources and Habi-
tats in the Middle Susitna River.Final Report.Entrix.Anchorage,
Alaska.
VI-8
-
--
-
.-
-
Kissner,P.O.1976.A study of chinook salmon in Southeast Alaska.Sport
Fish Div.,Alaska Dept.of Fish and Game,Juneau,AK AFS 41-4.17.
Klin~~er,S.,,and LW.Trihey.1984.Response of aquatic habitat surface
areas to mainstem discharge in the Talkeetna-to-Devil Canyon reach of the
Susitna River.E.Woody Trihey and Associates.Report for Alaska Power
Authority.Susitna Hydroelectric Project.Document 1693.1 vol.
Koski,K.1984.Interview,May 4,1984.Auke Bay Laboratory,U.S.National
Marine Fisheries Service,Auke Bay,Alaska.
Kruegrer,S.W.1981b.Freshwater habitat rel ationships Dolly Varden char
(Salvelinus malma (Walbaum».Habitat Division,Alaska Department of
Fish and Game.Anchorage,Alaska.
Krueger,S.W.
(Thyma 11 us_
Alaska.
1981a.Freshwater habitat relationships:Arctic grayling
arcticus).Alaska Department of Fish and Game.Anchorage,
-
Lee,K.M.1985.Resource partitioning and behavioral
young-of-the-year salmonids,Chena River,Alaska.
Univ.of Alaska,Fairbanks,Alaska.USA.
interactions among
Master's thesis.
-
-
Loar,J.M.,ed.1985.Application of habitat evaluation models in Southern
Appalacian trout streams.Environmental Sciences Div.,Oak Ridge Nation-
al Laboratory,Oak Ridge,TN.Publication 2383.310 pp.
Loftus,W.F.,and H.L.Lenon.1977.Pages 235-239 in Food habitats of salmon
smo lts Oncorhynchus tshawytshcha and Oncorhynchus keta from the Salcha
River,Alaska.Dept.of Biology,Central Michigan University,Mt.
Pl easant,MI.
Marcuson,P.1985.Larson Lake project progress report.Cook Inlet
Aquaculturl~Association,Anchorage,AK.
VI-9
McMahon,I.E.1983.Habitat Suitability Index Models:Coho Salmon.U.S.
Dept.Int.Fish Wildl.Serv.,FWS/OBS-82/10.49.
McNe"il,W.J.1969.Survival of pink and chum salmon eggs and alevins.Pages
101-117 .i.!!.T.G.Northcote,editor.Symposium of salmon and trout in
streams.University of British Columbia,Vancouver,Canada.
McNeil,W.J.,and W.H.Ahnell.1964.Success of pink salmon spawning rela-
tive to size of spawning bed materials.United States Fish and Wildlife
Service Special Scientific Report Fisheries 469:1-15.
McNeil,W.J.,R.L.Lantz,E.W.Claire,and J.R.Moring.1975.Some effects
of gravel mixtures on emergence of coho salmon and steel head trout fry.
Transactions of the American Fisheries Society.104:461-466.
McNeil,W.J.and J.E.Bailey.1975.Salmon rancher's manual.
Marine Fisheries Service,Auke Bay Alaska Fisheries Laboratory.
Oceanic and Atmospheric Administration.
National
National
Mecum,R.D.1984.Habitat util ization by fishes in the Tanana River near
Fairbanks,Alaska.Master's thesis,Univ.of Alaska,Fairbanks,Alaska •
.-
Meehan,W.R.,and 0.8.Sniff.1962.A study of the downstream migrations of
<anadromous fishes in the Taku River,Alaska.Trans.Amer.Fish.Soc.
91:399-407.
-
Meyer,P.R.,M.D.Kelly,K.A.Voos,ancfW.J.Wils-on.-19a-4.-Assessment of the
effects of the proposed Susitna Hydroelectric Project on instream temper-
ature and fishery resources in the Watana to Talkeetna Reach.Volume 1.
Alaska Environmental Information and Data Center.Anchorage,Alaska.
Milhous,R.I.,D.L.Wegner,and T.Waddle.1984.Users guide to the physical
habitat simulation system.U.S.Fish and Wildlife Service.Instream
t"-
Flow Information Paper 11.FWS/OBS-81/43 Revised.475pp.
-VI-lO
Milner,A.M.1983.The ecology of post-glacial streams in Glacier Bay
National Park,southeastern Alaska,Ph.D.Thesis.University of London.
239pp.
-.
-
-
.-
-
Mundie,J.H.1969.Ecological implications of the
streams.Pages 135-152 in 1.G.Northcote,ed.
trout in streams.H.R.MacMillan Lectures in
British Columbia,Vancouver,Canada.
diet of juvenile coho in
Symposium on salmon and
Fi sheri es,University of
-
-I
Neitzel,D.A.,and C.D.Becker.1983.Effects of dewatering on chinook
salmon redds:tolerance of four developmental phases to temperature
changes and reduced humidity.Battelle,Pacific Northwest Laboratory,
Richland,Washington,USA.
Neitzel,D.A.,C.D.Becker,C.S.Abernathy,D.W.Carlile,and E.W.Lusty.
1984.Laboratory simul ations of chi nook salmon redd dewatering:an
assessment of potential impacts at Vernita Bar.Battelle,Pacific
Northwest Laboratories.Prepared for the Public Utility District of
Grant County,Washington.Richland,Washington,USA.
Olsen,R.W.1979.Methodologies for use in project-related studies.Pages
157-169 in:Proceedings from Hydropower:a National Energy Resource.
March 11-16,1979,Engi neeri ng Foundation Conference.In cooperation
with U.S.Army Corps of Engineers.Easton,MD.
Raleigh,R.F.,Terry Hickman,R.Charles Solomon,Patrick C.Nelson.1984.
Habitat suitability information:Rainbow trout,U.S.Fish Wildl.Servo
IFWSjOBS-82j 10.60.
Reiser,D.W.and T.C.Bjorn.1979.Influence of forest and range land
management on anadromous fish habitat in the western United States and
Canada.Habitat requi rements of anadromous sa lmoni ds.USDA Forest
Service Gen.Tech.Rept.PNW-96.
Reiser,D.W.,alnd R.G.White.1981.Influence of streamflow reductions on
salmonid embryo development and fry qual ity.Idaho Water and Energy
VI-11
1985.Invertebrate drift at selected sites
Preliminary results.Trihey and Associ-
"""'I
-
r
i
.....
-
,..."
-
Resources Research Institute,University of Idaho.Research Technical
Completion Report,Project A-058-IDA,Moscow,Idaho,USA.
Reub 9 G.,R.Elder and R.C.Wilkinson.1985.(will provide later)
Richards,J.C.and A.M.Milner.
in the middle Susitna River:
ates.Technical Memorandum.
Richards,K.1979.Aspects of the juvenile life history of spring chinook
salmon (Oncorhynchus tshawytscha)in Deshka River,Alaska determined from
adult scale analysis and migrant trapping.M.S.Thesis.Oregon State
University,Corvallis,Oregon •
R&M Consultants.1985.(will provide later)
Roth,K.J.and M.E.Stratton.1985.The migration and growth of juvenile
salmon in the Susitna River.Report No.7,Part 1.In: Resident and
Juvenile anadromous fish investigations (May-October 1984).D.C.
Schmidt,S.S.Hale,andD.L.Crawford,eds.Susitna River Aquatics
Studies.Alaska Department of Fish and Game.Anchorage,Alaska.
,D.C.Gray,and D.C.Schmidt.1984.The outmigration of juvenile
salmon from the Susitna River above the Chulitna River confluence.
Report 2.Part 1.~:Resident and juvenile anadromous fish investiga-
tions (May-October 1983).D.C.Schmidt,S.S.Hale,D.L.Crawford,and
P.M.Suchanek eds.Susitna Hydro Aquatic Studies.Alaska Dept.of Fish
and Game.Anchorage,Alaska.
Sautner,J.S.,L.J.Vining and L.A.Rundquist.1984.Chapter 6:An eval-
uation of passage conditions for adult salmon in sloughs and side chan-
nels of the middle Susitna River.In:Report No.3:Aquatic Habitat
and instream flow investigations (May-October 1983).C.Estes and D.
Vincent-Lang,eds.Susitna Hydro Aquatic Studies.Alaska Dept.of Fish
and Game,Anchorage,Alaska.
VI-12
Schmidt,D.C.,S.S.Hale,D.L.Crawford,and P.M.Suchanek.1984.Report 2.
Resident and juvenile anadromous fish investigations (May-October 1983).
Susitna Hydro Aquatic Studies.Alaska Dept.of Fish and Game,Anchorage,
Alaska.
Schmidt;D.C.,S.S.Hale,D.Crawford.1985.Report No.7.
juven"ile fish investigations (May-October 1984).Susitna
Studies.Alaska Dept.of Fish and Game,Anchorage,Alaska.
Resident and
River Aquati c
Scott,W.B.and E.J.Crossman.1973.Freshwater Fishes of Canada.Volume
19.Fisheries Research Board of Canada.Ottawa,Canada.
Shumway,D.L.,C.L Warren,and P.Doudoroff.1964.Influence of oxygen
concentration and water movement on the growth of steel head trout and
Icoho sa 1mon embryos.Trans.Am.Fi.sh.Soc.93:342-356.
Silver,S.J.1960.The influence of water
the development of salmonid embryos.
College,Corvallis,Oregon,USA.
velocity and dissolved oxygen on
Master's thesis.Oregon State
Smith,A.K.1973.Development and application of spawning velocity and depth
criteria for Oregon salmonids.Trans.Am.Fish.Soc.102:312-316.
Stalnaker,C.B.,and J.L.Arnette,
mi nati on clf stream resource
State University,Logan,UT.
199 pp.
eds.1976.Methodologies for the deter-
flow requirements:an assessment.Utah
Report for U.S.Fish and Wildlife Service.
.-
-
Stewar'd,C.R.and E.W.Trihey.1984.Fish habitat a.nd instream flow rela-
tionships in the middle reach of the Susitna River:An extrapolation
methodology.Unpublished manuscript.
___..'R.C.Wil kinson,and A.Mi 1nero 1985.Response of juvenil e chinook
habitat to mainstem discharge in the Talkeetna-to-Devil Canyon segment of
VI-13
-
-.
-
-
-
-
.....
-
the Susitna River,Alaska.E.Woody Trihey &Associates.Draft report
for Alaska Power Authority,Anchorage,Alaska.
Stratton,M.E.1985.Winter studies of juvenile chinook and coho salmon in
the middle Susitna River 1984-85 part 1 in Report No.11.Winter studies
of resident and juvenile anadromous fish (October 1984 :..May 1985).
Susitna ~~dro Aquatic Studies Alaska Department of Fish and Game.
Anchorage,Alaska.
Suchanek,P.M.Kuntz,K.J.and J.P.McDonell.1985.The relative abundance,
distribution,and instream flow relationships of juvenile salmon in the
lower Susitna River.Part 2 in Crawford,D.L.et al.eds.Report No.7.
Resident and juvenile anadromous fish investigations (May -October
1984).Susitna Hydro Aquatic Studies Alaska Department of Fish and Game,
Anchorage,Alaska.
,R.P.Marshall,S.S.Hale,and D.C.Schmidt.1984.Juvenile rearing
suitability criteria.Report 2,Part 3.In:Resident and juvenile
anadromous fish investigations (May-October 1983).D.C.Schmidt,S.S.
Hale,D.L.Crawford,and P.M.Suchanek,eds.Susitna Hydro Aquatic
Studies.Alaska Department of Fish and Game,Anchorage,Alaska.
Sundet,R.L.1985.Winter resident fish distribution and habitat studies
conducted in the Susitna River below Devil Canyon,1984-1985.Report No.
11.Winter Studies of Resident and Juvenile Anadromous Fish (May-October
1984)Parts 1 and 2.
Sundet,R.L.,and M.N.Wenger.1984.Resident fish distribution and popu-
'lation dynamics in the Susitna River below Devil Canyon.Report No.2,
Part 5.In:Resident and juvenile anadromous fish investigations (May -
October 1983).D.C.Schmidt,S.S.Hale,D.Crawford,P.Suchanek,eds.
Susitna Hydro Aquatic Studies.Alaska Department of Fish and Game,
Anchorage,Alaska.
Sundet,R.L.,and S.D.Pechek.1985.Resident fish distribution and life
history in the Susitna River below Devil Canyon.In:Report 7,Part 3.
VI-14
,....
I
Resident and juvenile anadromous fish investigations (May -October
1984).D.C.Schmidt,S.S.Hale,and D.l.Crawford,eds.Susitna River
Aquatic Studies Program.Alaska Department of Fish and Game,Anchorage,
Alaska.
Thompson,K.1972.Determining streamflows for fish life.pp.31-45.In:
Proceedings of the Instream Flow Requirements Workshop.March 15-16,
Portland,Oregon.
Trihey,E.W.1979.The IFG incremental methodology.Pages 24-44 in:G.L.
Smith,ed.Workshop in Instream Flow Habitat Criteria and Modeling.
Colorado Water Resources Research,Colorado State University,Fort
Collins,CO.Information Series No.40.
1982.Prel iminary assessment
slough habitat above Talkeetna.
Buffalo,NY.
of access by spawning salmon to side
Prepared for Acres American,Inc.
1983.Preliminary assessment of access by spawning salmon into
!Portage Creek and Indian River.Report for Alaska Power Authority,
Anchorage,AK.31pp.
Univeirsity of Alaska,Arctic Environmental Information and Data Center.1985.
)~ssessment of the effects of the proposed Susitna hydroelectric project
on i nstream temperature and fi shery resources in the Watana to Talkeetna
l"each.F"jnal Report Volume 1.Report for Alaska Power Authority,
Anchorage,AK.130 pp.
f"""U.S.Fish and W'ildlife Service (USFWS).Unpublished draft:Habitat suitabil-
i~y index models:Sockeye salmon,USFWS.Anchorage,Alaska.
-
Van Nienhenhyce,E.1985.Summary of Preliminary Results:Task 31 Primary
production monitoring effort.University of Alaska Arctic Environmental
Information and Data Center.Technical Memorandum.13 p.
VI-IS
Velsem,F.P.J.1980.Embryonic development in
(Oncorhynchus nerka).Canadi an Journal of
Sciences,Special Publication Number 49.
eggs of sockeye salmon
Fisheries and Aquatic
,."..
I
--
Vince,nt-Lang,D.,A.Hoffman,A.Bingham,and C.Estes.1984a·.Chapter 9:
Habitat suitability criteria for chinook,coho,and pink salmon spawning
in tributaries of the middle Susitna River.In:Report No.3.Aquatic
habitat and instream flow investigations (May -October 1983).C.Estes
and D.Vincent-Lang,eds.Susitna Hydro Aquatic Studies.Alaska Depart-
ment of Fish and Game.Anchorage,Alaska.
Vincent-Lang,D.and A.Hoffman,A.Bingham,C.Estes,D.Hilliard,C.
Steward,E.Trihey,and S.Crumley.1984b.Chapter 7:An evaluation of
chum and sockeye spawning habitat in sloughs and side channels of the
middle Susitna River.In:Report No.3:Aquatic habitat and instream
flow investigations (May -October 1983),C.Estes and D.Vincent-Lang,
eds.Susitna Hydro Aquatic Studies,Alaska Department of Fish and Game,
Anchorage,Alaska.
Vining,L.J.,J.S.Blakely,and G.M.Freeman.1985.An evaluation of the
incubation life phase of chum salmon in the middle Susitna River,Alaska.
l/Jinter Aquatic Investigation:Sept.1983 -May 1984.Report No.5,
Vol.1.Alaska Department of Fish and Game,Susitna Hydro Aquatic
Studies.Anchorage,Alaska.
Waite,D.C.1979.Chinook enhancement on the Kenai Peninsula.F.R.E.D.
Div.,Alaska Dept.of Fish and Game.Juneau,AK AFS 4601.51 pp.
Wangaard,D.and C.
regimes on the
sockeye salmon.
Research Center.
Burger.1983.Effects of various water temperature
egg and alevin incubation of Susitna River chum and
U.S.Fish and Wildlife Service,National Fishery
Anchorage,Alaska.
WeSChE!,LA.1980.The WRRI trout cover rating method.Development and
application.Water Resources Research Institute,Water Resources Series
-.~
No.78,University of Wyoming,Laramie,WY.
-VI-16
Wickett,W.P.1958.Review of certain environmental factors affecting the
-production of pink and chum salmon.J.Fish.Res.Bde Can.15:1103-1126.
Wilson,W.J.,E.W.Trihey,J.E.Baldrige,C.D.Evan,J.G.Thiele,and D.E.
Tr·udgen.1981.An assessment of environmental effects of construction
and operation of the proposed Terror Lake hydroelectric facility,Kodiak,
Alaska,Instream flow studies final report.Arctic Environmental
Information and Data Center.University of Alaska,Anchorage,Alaska .
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