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ALASKA DEPARTMENT OF FISH AND GAME
SUSITNA HYDRO AQUATIC STUDIES REPORT SERIES
Document No.2846
Susitna File No.4.3.1.6
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ALASKA DEPARTMENT OF FISH AND GAME
SUSITNA HYDRO AQUATIC STUDIES
REPORT NO.8
Availability of Invertebrate Food Sources
for Rearing Juvenile Chinook Salmon
in Turbid Susitna River Habitats
Prepared for:
ALASKA POWER AUTHORITY
334 W.FIFTH AVE •
ANCHORAGE.ALASKA 99501
June 1985
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NOTICE
ANY QUESTIONS OR COMMENTS CONCERNING
THIS REPORT SHOULD BE DIRECTED TO
THE ALASKA POWER AUTHORITY
SUSITNA PROJECT OFFICE
PREFACE
This report is one of a series of reports prepared for the Alaska Power
Authority (APA)by the Alaska Department of Fish and Game (ADF&G)to
provide information to be used in evaluating the feasibility of the
proposed Susitna Hydroelectric Project.The ADF&G Susitna Hydro Aquatic
Studies program was initiated in November 1980.Reports prepared by the
ADF&G Susitna Hydro Aquatic Studies program prior to 1983 are available
from the APA.Reports prepared after 1983 are sequentially numbered as
part of the Alaska Department of Fish and Game Susitna Hydro Aquatic
Studies-Report Series.Titles in this report series are:
This report,Report Number 8,summarizes the results and findings of the
juvenile chinook salmon food availability study conducted during the
1984 open water (May -October)field season.
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Report
Number
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2
3
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Title
Adult Anadromous Fish Investigations:
May-October 1983
Resident and Juvenile Anadromous Fish
Investigations:May -October 1983
Aquatic Habitat and Instream Flow
Investigations:May -October 1983
Access and Transmission Corridor Aquatic
Investigations:May -October 1983
Water Aquatic Investigations:
September 1983 -May 1984
Adult Anadromous Fish Investigations:
May -October 1984
Resident and Juv-enil e Anadromous Fish
Investigations:May -October 1984
Availability of Invertebrate Food Sources
for Rearing Juvenile Chinook Salmon
in Turbid Susitna River Habitats
Summary of Salmon Fishery Data for
Selected Middle Susitna River Sites
Publication
Date
April 1984
July 1984
September 1984
September 1984
March 1985
1985
1985
1985
1985
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AVAILABILITY OF INVERTEBRATE FOOD SOURCES
FOR REARING JUVENILE CHINOOK SALMON
IN'TURBID SUSITNA RIVER HABITATS
1985 Report Number 8
by
Tim F.Hansen and J.Craig Richards
Alaska Department of Fish and Game
Susitna Hydro Aquatic Studies
Third Floor,Michael Building
620 East Tenth Avenue
Anchorage,Alaska 99501
ABSTRACT
Benthic and drifting invertebrates were sampled from May through October
1984 to evaluate available fish food resources and the gain and loss of
benthic invertebrate habitat resulting from changes in flow.Four side
channel and side slough sites were sampled at head and mid-section
locations using drift nets and modified Hess type samplers.Juvenile
chinook salmon were also sampled using electro-fishing techniques to
correlate the available food sources with that being utilized.
A total of 52 invertebrate taxa were identified in drift and benthic
samples,with Chironomidae being the dominant taxa.The proportions of
numbers of invertebrates found in the stomachs of juveni 1e chinook
salmon were closely correlated with the proportions of invertebrates
available in the drift.Drift samples collected under breached con-
di ti ons i ndi cated that invertebrates were bei ng transported from the
mainstem into the side channel s and side sloughs.The quantity of
drifting invertebrates in side channels and side sloughs under
unbreached conditions was negligible compared to the drift under
breached conditions when total drift was considered.
Habitat suitability criteria were developed and weighted usable area was
estimated for invertebrates which were common to drift,benthos,and the
diet of juvenile chinook salmon by behavioral type (i .e.burrower,
swimmer,clinger,and sprawler).The densities of each of the
behavioral types generally correlated with water velocity and substrate
type.Depth of water did not appear to be an important factor influ-
encing the density of organisms.Water velocities less than 0.4 ft/sec
and substrates compri sed of s11 ts and sands genera 11y supported the
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highest mean densities of burrowers which were made up primarily
of Chironomidae.Rubble substrates with components of large gravel or
cobble and water velocities between 1.6 ft/sec and 2.6 ft/sec generally
supported the highest mean densities of swimmers and clingers.
Sprawlers did not appear to preferentially utilize any particular
substrate or water velocity.
Projected weighted usable area for each of the behavioral types was
clearly a function of mainstem discharge.The minimum controlling
mainstem discharge for each of the study sites generally produced the
greatest amount of burrower habitat weighted usable area.The maximum
amount of weighted usable .area for swimmer,clinger,and .sprawler
habitat at all study sites was reached at a mainstem discharge above
25,000 cfs.
In conclusion,naturally fluctuating mainstem flows which occasionally
inundated sampling sites appeared to maintain a diverse benthic fauna
and appeared to provide drifting food organisms within sampling sites
thereby contributing to the overall rearing potential of these sites for
juvenile chinook salmon.
ii
TABLE OF CONTENTS
ABSTRACT...........................................................;
TABLE (IF CONTENTS ••••••••••••••••••••••••••••••••••••••••••••••••••iii
LIST OF FIGURES....................................................vi
LI·ST OF APPENDIX FIGURES .ix
LIST OF TABLES •••••••••••••••••••••••••••••••••••".................x
LIST OF APPENDIX TABLES ••••••••••••••••••••••••••••••••••••••••••••xii
1.0
2.0
INTRODUCT ION ••••••••••••••••••••••'••••••.••••••••••••••••••••e·.
METHODS ••••••••-•••••••••••••••-•••••••••••••••••-•••••••••••••••
1
5
2.1 Field Sa-mpl ing ........•....••'.....•.........................5
2.1.1
2.1.2
2.1.3
2.1.4
2.1.5
Study Site -Selectio-n.,.
Invertebrate Drift ' .
Benthic Invertebrates •••••••••••••••••••••••••••••••••••
Juvenile Chinook Salmon •••••••••••••••••••••••••••••••••
Turbidity ....'!'••••.••••••••••••••••••••••••••••••••••••••
5
5
12
12
14
2.2 Laboratory An,alysis .14
2.2.1
2.2.2
Sample Handling and Storage •••••••••••••••••••••••••••••
Invertebrate Identification and Enumeration •••••••••••••
14
14
2.3 Data Analysis ...............•...............................15
2.3.1
2.3.2
Invertebrate Drift .
Benthic Invertebrates •••••••••••••••••••••••••••••••••••
15
16
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2.3.2.1
2.3.2.2
2.3.2.3
Standing Crop Estimation ••••••••••••••••••••••••••••
Suitability Criteria Development ••••••••••••••••••••
Wei'ghted Usable Area .
16
17
21
2.3.3
2.3.4
Invertebrate Larval Development •••••••••••••••••••••••••
Juvenile Chinook Salmon •••••••••••••••••••••••••••••••••
22
22
3.0 RESUL TS •••••••••••••••••••••••••••••••••••••••••••••••••••••••23
3.1
3.1
Invertebrate Drift .
Benthic Inertebrates .
23
28
3.2.1 Benthic Habitat Suitability Criteria ••••••••••••••••••••
iii
30
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TABLE OF CONTENTS (Continued)
3.2.1.1 Depth ••••••,~.......................................30
3.2.1.2 Velocity............................................45
3.2.1.3 Substrate...........................................46
3.2.2 Benthic Weighted Usable Area Projections................47
3.3 Invertebrate Larval Development.............................52
3.4 Juvenile Chinook Salmon Diet................................52
3.5 Turbidity at Study Sites and Mainstem
Susitna River ••••••••••••••••••••.••••••••••••••.•••••••••.••52
4.0 DISCUSSION....................................................57
4.1 Available Food Sources for Juvenile Chinook
Salmon in Side Channels and Side Sloughs....................57
4.2 Effects of Flow on the Distribution and
Abundance of Benthic Invertebrates in Side
Channels and Side Sloughs...................................59
4.2.1 Habitat Suitability.....................................59
4.2.2 Weighted Usable Area....................................60
4.3 Utilization of Available Food by Juvenile
Chinook Salmon in Side Channels and Side
Sloughs ••••••••••••••••••••••••••••••••••~............••••••62
4.4 Conclusions and Future Research.............................63
5.0 CONTRIBUTORS..................................................66
6.0 ACKNOWLEDGEMENTS...............................................67
7.0 LITERATURE CITED..............................................68
8.0 APPENDICES....................................................73
Appendix A Study Site Hydrographs,Rating Curves,
and Discharge Data ••••••••.••••••••••••••••••••••A-I
Appendix B Benthic and Drift Invertebrate Data ••••••••••••••B-1
Appendix C Results of the Multiple Regression
Analysis of Drift Data •••••••••••••••••••••••••••C-l
tv
TABLE OF CONTENTS (Continued)
-Appendix D Formula for·Calculating the Shannon-
Weaver Diversity Index and Eveness
Index .D-1
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Appendix E Juvenile Chinook Salmon Stomach
Content Data •••••••••••••••••••••••••••••••••••••E-1
Appendix F Weighted Usable Area Projection
Data.............................................F-1
Appendix G Water Turbidity Data •••••••••••••••••••••••••••••G-1
v
LIST OF FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Map of the middle Susitna River showing the
four 'Food Availability Study sampling sites,
1984.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Map of Slough 9 showing invertebrate and
juvenile chinook salmon sampling locations,
June through September,1984...........................6
Map of Side Channel 10 showing invertebrate
and juvenile chinook salmon sampling loca-
tions,June through September,1984....................7
Map of Upper Side Channel 11 showing
invertebrate and juvenile chinook salmon
sampling locations,June through August,
1984.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Map of upper Side Channel 21 and Slough 21
showing invertebrate and juvenile chinook
salmon sampling locations,June through
September,1984 ,.............................9
Invertebrate samp1 ing gear used in the Food
Availability Study,1984.Adapted from
Merritt and Cummins·(l978)•••••••••••.•••••••••••••••••10
Scatter plots jJf standardized drift densities
(no/lOaD feet of water)of eight inverte-
brate groups,head numbers vs.IFG-4 numbers.
Densities are transformed log (x+1)••••••.•.••••••••••26..e .
Scatter plots jJf standardized drift densities
(no/lOaD feet of water)of eight inverte-
brate groups,head numbers vs.IFG-4 numbers.
Densities are transformed loge (x+1)••••.••••••••••.•••27
Average density of benthic fish food orga-
nisms (no./yd 2 )by behavioral type in riffle,
run,and pool habitats in side chalJnels and
si de sloughs,from June 24 to July 10 and
August 23 to September 7,middle Susitna
River,Alaska,1984.Behavioral groups with
fewer than five individuals per square yard
are not shown..........................................31
Figure 10 Average number of burrower invertebrates per
benthic sample for each depth increment,with
hand fitted suitability curve,middle Susitna
River,A'a~ka,1984 ..•..........••..........•..........32
vi
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LIST QF FIGURES (Continued)
Figure 11 Average number of swimmer invertebrates per
benthic sample for each depth increment,with
hand fitted suitability curve,middle Susitna
River,Alaska,1984 ...•......•..........................33
Figure 12 Average number of clinger invertebrates per
benthic sample for each depth increment,with
hand fitted suitability curve,middle Susitna
River,Alaska,1984 ......................•.•...........34
Figure 13 Average number of sprawler invertebrates per
benthic sample for each depth increment,with
hand fitted suitability curve,middle Susitna
River,Alaska,.1984 .......•..........,35
Figure 14 Average number of burrower invertebrates per
benthic sample for each velocity increment,
wi th hand fi tted su i tabi 1i ty curve,mi ddl e
Susitna River,Alaska,1984 ••••••••••••••••••••••••••••36
Figure 15 Average number of swimmer invertebrates per
benthic sample for each velocity increment,
with hand fitted suitability curve,middle
Susitna River,Alaska,1984 ••~.........................37
Figure 16 Average number of cl inger invertebrates per
benthic sample for each velocity increment,
with hand fitted suitabil ity curve,mi ddle
Susitna River,Alaska,1984............................38
Figure 17 Average number of sprawler invertebrates per
benthic sample for each velocity increment
with hand fitted suitability curve,middle
Susitna River,Alaska,1984 •••••••••••••••••••••••.••••39
Figure 18 Average number of burrower invertebrates per
benthic sample for each substrate increment,
with hand fitted suitability curve,middle
Susitna River,Alaska,1984 .•••••••••••••••••••••••••••40
Figure 19 Average number of swimmer invertebrates per
benthi c sampl e for each substrate "j ncrement,
with hand fi tted suitabil ity curve,mi ddl e
Susitna River,Alaska,1984 •••••••••••••••••.••••••••••41
Figure 20 Average number of cl il1ger invertebrates per
benthic sample for each substrate increment,
wi th hand fi tted suitabil i ty curve,mi ddl e
Susitna River,Alaska,1984 •••••••••••••••••••.••.•••••42
vii
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LIST OF FIGURES (Continued)
Figure 21 Average number of sprawler invertebrates per
benthic sample for ea'ch substrate increment,
with hand fitted suitability curve,middle
Susitna River,Alaska,1984 ••••••.•.••••••••.••••••.•.•43
Figure 22 Projections of gross surface area and WUA of
burrower,swimmer,cl inger,and sprawler
invertebrate habitat as a function of site
flow and mainstem discharge for the Slough 9
mode 11 ;n9 s1te.•••. •••••••••••. . •. ••••••••••. ••••••••••48
Figure 23 Projections of gross surface area and WUA of
burrower,swimmer,clinger,and sprawler
invertebrate habitat as a function of site
flow and mainstem discharge for the Side
Channel 10 modelling site ••••.••••••.•••.••••••••••••••49
Figure 24 Projections of gross surface area and WUA of
burrower,swimmer,clinger,and sprawler
invertebrate habitat as a function of site
flow and mainstem discharge for the Upper
Side Channel 11 modelling site ••••••••.•••.••••••.••••.50
Figure 25 Projections of gross surface area and WUA of
burrower,swimmer,clinger,and sprawler
invertebrate habitat as a function of site
flow and mai nstem di scharge for the Si de
Channel 21 mode"i ng si te •.•••.~•••••••••••••.••••••• ••51
Figure 26 Percent composition of invertebrates in
benthic,drift,and juvenile chinook stomach
content samples taken at FAS sites,middle
Susitna River,Alaska,1984 ••••••.•••.•••••..••••••.•••54
Figure 27 Percent composition of aquatic insect
behaviroal groups in benthic drift,and
juvenile chinook stomach content samples
taken at FAS sites,middle Susitna River,
Al aska,1984...........................................55
Figure 28.Percent of total numbers of aquatic and
terrestrial insect groups in juvenile chinook
salmon stomachs from FAS sites,June through
September 1984,middle"Susitna River,Alaska •.•.•••..••64
viii
Figure A-I
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LIST OF APPENDIX FIGURES
APPENDIX A
Hydrograph (discharge versus time)for June -
September 1984 for the Susitna River at Gold
.Creek (RM 136.5),Slough 9 (RM 128.3),and
Side Channel 10 (RM 133.8)•.•.•.•.•••.••..••.••••••••••A-3
Figure A-2 Hydrograph (discharge versus time)for June -
September 1984 for the Susitna River at Gold
Creek (RM 136.5),Upper Side Channel 11 (RM
163.0),and Side Channel 21 above over flow
channel A5 (RM 141.8)••••••••••••••••••••••.•••••••••••A-4
Figure A-3 Rating curve for predicting flow at Slough 9
at mainstem discharges at Gold Creek between
19,000 cfs and 35,000 cfs ••••••••••••••••••••••••••••.•A-5
Figure A-4 Rating curve for predicting flow at Side
Channel 10 at mainstem discharges at Gold
Creek between 19,000 cfs and 35,000 cfs ••••••••••••••••A-6
Figure A-5 Rating curve for predicting flow at upper
Side Channel 11 at mainstem discharges at
Gold Creek between 13,000'cfs and 35,000
cfs •••••.•••••.••••••••••.••••••••••••••••••••••••••••••A-7
Figure A-6 Rating curve for predicting flow at Side
Channel 21 above Channel A5 at mainstem
discharges at Gold Creek between 20,000 cfs
and 35,000 cfs ••••:••••••••••••••••••••••••••••••••••••A-8
ix
-LIST OF TABLES
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Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Table 10
Food ava i 1abi 1i ty study sampling dates,
middle Susitna River,Alaska,1984 •••••••••••••••••••••11
Substrate classification scheme utilized to
evaluate substrate composition at each
benthi c sampl i ng poi nt (Vi ncent-Lang et a1.
1984). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Invertebrate taxa grouped by behavioral type
(Merritt and Cummins,1978)............................18
Depth and velocity increments used for suita-
bility criteria development ••••••••••••••••••••••••••••20
Substrate class groupings used for suita-
bility criteria development ••••••••••••••••••••••••.•••20
Relative density of invertebrate drift per
cubic yard of water by site and drift net
location,June through August 1984,middle
Susitna River,Alaska.R=Rare (0.001-0.009/
yd 3 ),S=Sparse (0.010-0.099/yd 3 ),C=Corrnnon
(0.100-0.999/yd 3 ),A=Abundant (1.000-9.999/
yd 3 )••••••_•••••••••••••••••••••••••••••••••••.••••••••••24
Relative density of benthic invertebrates per
square yard by site,June through September,
1984 middle Susitna River,Alaska.R=Rare
(0.1-0.9/yd 2 ),S=Sparse (1.0-9.9/yd 2 ),
C=Common (10.0-99.9/yd 2 ),A=Abundant (100.0-
999.9/yd2 )•••••••••••••••••••••••••••••••••••••••••••••29
Suitability criteria values for invertebrate
behavioral groups for depth,velocity,and
substrate type,middle Susitna River,Alaska,
1984.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Percentage of early,middle,and late instar
larval aquatic insects and the total number
of individua.ls examined (),middle SlJsitna
River,Alaska,1984.Individuals examined
from April,May,September,and October
samples are from synoptic surveys ••••••••••••••••••••••53
Standardized densities (no/1000 feet 3 )of
drifting invertebrates (Invert.)and adult
aquatic insects (Adult)at head and IFG-4
sites,middle Susitna River,Alaska,1984 ••••••••••••••58
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LIST OF TABLES (Continued)
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Table 11 Diversity ±S.E.,eveness (Poole 1974),
density,and number of taxa of benthic inver-
tebrate communities from riffle,run,and
pool habitats in side channels and side
sloughs of the middle Susitna River,Alaska,
1984.Density and number of taxa are
reported as the average number per square
yard ±98%confidence interval.•••••••.•••••••••••••••••61
xi
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LIST OF APPENDIX TABLES
APPENDIX A
Table A-I Side slough and side channel water surface
elevation and flow measurements,and the
corresponding mean daily Susitna River
discharges at Gold Creek (USGS 15292000)used
to construct rating curves for the four FAS
sites.................................................A-9
APPENDIX B
Table B-1 Occurrence of invertebrates by life stage
(i=immature,p=pupa,a=adult)and sample type
(B=Benthos,D=Drift,F=Fi sh Stomach)at four
sample sites,middle Susitna River,Alaska,
1984 ••••••••••••••••••••••.••••••••••••••••••••••.••••B-3
Table B-2 Total numbers of invertebrate larvae and
adults ( )in drift samples collected at
Slough 9,middle Susitna River,Alaska,1984.
Terrestrial insect groups and non-insect
groups are not differentiated by larvae or
adult •••••••••.••.••.••••••.••.••~.••.•.•••.•.•.•.....B-6
Table B-3 .Total numbers of invertebrate larvae and
adults ( )in drift samples.'collected at
Side Channel 10,middle Susitna River,
Alaska,1984.Terrestrial insect groups and
non-insect groups are not differentiated by
larvae or adult.......................................8-8
Table B-4 Total numbers of invertebrate larvae and
adults ( )in drift samples collected at
Upper Side Channel 11,middle Susitna River,
Alaska,1984.Terrestrial insect groups and
non-insect groups are not differentiated by
larvae or adult ••..•.••.•••.•••••.••..•••••••.•.•••..•B-10
Table B-5 Total numbers of invertebrate larvae and
adults ( )in drift samples collected at
Upper Side Channel 21,middle Susitna River,
Alaska,1984.Terrestrial insect groups and
non-insect groups are not differentiated by
1arvae ·or.adul t ..·8-12
Table 8-6 Densities (no./yd 3 of water)and rates (no.1
min.)of invertebrate drift during June,
July,and August at slough and side channel
head and IFG sites,middle Susitna River,
Alaska,1984 .•.••..•.••..•••...••.••.••..••..••.•..••.8-14
xii
Table 8-7 Tota 1 numbers of benthi c invertebrates and
the number of samples ( )in which each taxa
was found at Slough 9,middle Susitna River,
Alaska,1984 ..•.......................................8-16
p!IUIIII"
,...,
Table 8-8 Total numbers of benthic invertebrates and
the number of samples ( )in which each taxa
was found at Side Channel 10,middle Susitna
River,Alaska,1984 •••••••••••••••:•••••••••••••••••••8-17
Table 8-9 Total numbers of benthic invertebrates and
the number of samples ( )in which each taxa
was found at Upper Side Channel 11,middle
Susttna River,Alaska,1984 •••••••••••••••••••••••••••8-18
Table 8-10 Total numbers of benthic invertebrates and
the number of samples ( )in which each taxa
was found at Side Channel 21,middle Susitna
River,Alaska s 1984 ............•......•...•....•...•..8-19
APPENDIX C
Table C-1 Analysis of Variance •••••••••••••••••••••••••••.••••••C-3
Table C-2 Results of Student's t-test •••••••••••••••••••••••••.•C-3
Table C-3 Analysis of variance for new hypothesis •••••••••••••••C-4
Table C-4 Results of Student's t-test for new hypothesis ••••••••C-4
APPENDIX E
Table £-1 Number and kind of invertebrate larvae and
adul ts ( )from the stomachs of juveni 1e
chinook salmon caught by electrofishing and
drift nets at invertebrate sampling sites,
middle Susitna River,Alaska,1984 ••••••••••••••••••••E-2
APPENDIX F
Table F-1
Table F-2
Projections of gross area and WUA
(ft sq/1000 ft)of benthic invertebrate
habitat at Slough 9•.•.•........••..•..•..............F-3
Projections of gross area and WUA
(ft sq/1000 ft)of benthic invertebrate
habitat at Side Channel 10 ••••••••••••••••••••••••••••F-5
Table F-3 Projections of gross area and WUA
(ft sq/1000 ft)of benthic invertebrate
habitat at Upper Side Channel 11 •••••••••••••••••••..•F-6
Table F-4 Projections of gross area and WUA
(ft sq/1000 ft)of benthic invertebrate
habitat at Side Channel 21 ••••••••••••••••~•••.•••••••F-8
xiii
I'*':'"
!
I
APPENDIX G
Table G-l Turbidity values·in nephelometric turbidity
units (NTU)from five locations,middle
Susitna River,Alaska,1984 •••••••••••••••••••••••••••G-2
xiv
1.0 INTRODUCTION
Habitat variables such as cover,riparian vegetation,water depth and
velocity,and food supply have all been determined to be important
variables influencing the overall suitability of instream habitats for
rearing juvenile salmon.Although there is no definite evidence that
any of these variables is the ultimate factor limiting the carrying
capacity of a particular habitat for rearing by juvenile salmonids,it
is cl ear that the availabi 1ity of suitabl e food is of·consi derabl e
importance.
Food sources utilized by juvenile salmon have generally been found to
consist of aquatic invertebrates which inhabit the various niches of the
instream environment.Many researchers have examined the instream
variables which influence the distribution and abundance of these
invertebrate food organisms and have concluded that water depth,water
velocity,and substrate type are three of the most important controlling
factors (Kimble and Wesche 1975;Cummins 1975).There is some contro-
versy,however,as to which of these factors exerts the greatest
control.It is likely,however,that invertebrate species select their
habitats on the basis of combinations of the above factors rather than
on the basis of the factors individually (Ulfstrand 1967).Ulfstrand
based this conclusion on the ability of different combinations of depth,
velocity,and substrate to entrap debris which could be used as food by
invertebrates.
Additional studies have suggested that optimum invertebrate habitat
could be identified according to combinations of available depth,
velocity,and substrate type.Pearson et ale (1970)suggested that
optimum habitat conditions for invertebrate organisms were reached when
streamflows resulted in the greatest amount of riffle-like habitat
having water velocities of approximately 2.0 feet per second (ft/sec).
Banks et al.(1974)made optimum streamflow recommendations for inverte-
brate habitat by assuming that the most preferred streamflow would be
that which would provide the maximum surface acreage with water
velocities of 1.5-3.49 ft/sec and depths of 0.50-2.99 feet.The
California Department of Fish and Game (1975)based streamflow recommen-
dations for invertebrate habitat on habitat curves with streamflow as
the independent variable generated from weighted depth,velocity,and
substrate measurements collected along transects.Newell (1976)used
linear regression analysis with streamflow as the independent variable
to predict macroinvertebrate densities at different flows in the Yellow-
stone River,Montana.
One of the most recent predictive modelling procedures for describing
benthic invertebrate habitat has been developed by the U.S.Fish and
Wildlife Service (USFWS)Instream Flow Group (IFG)(Judy and.Gore 1979).
The IFG used many of the same modell i ng techniques whi ch were developed
for evaluating instream fish habitat for the assessment of the instream
flow requirements of benthic invertebrate habitat (Bovee and Cochnauer
1977,Bovee and Milhous 1978,Bovee et ale 1979 and Bovee 1979).These
modelling techniques utilize water depth,velocity,and substrate type
as the dominant hydraulic variables to quantify the responses of benthic
invertebrate habitat to changes in streamflow.
1
Information concerning the density and the number of different kinds of
invertebrate foods available to rearing juvenile salmon and the habitat
requirements of these invertebrate organisms is not well known for the
Susitna River as only limited studies of invertebrate organisms have
been conducted to date (ADF&G 1977,1978 and 1983a).The studies
conducted to date have been limited to describing the diet of juvenile
chinook,coho,and sockeye salmon and the kinds of invertebrate foods
available to them.No habitat modelling evaluations have been conducted
describing the density and flow requirements of invertebrates in habi-
tats utilized by juvenile salmon.
This report presents the results of the 1984 Alaska Department of Fish
and Game Susitna Aquatic Studies Program Food Availability Study (FAS).
The study was designed to quantify invertebrate habitat and the inverte-
brate food organisms available to juvenile chinook salmon in selected
side channel and side slough habitats of the middle Susitna River at
di·fferent mainstem flows.Side channel and side slough habitats of the
middle Susitna River were selected as evaluation habitats as these
habitat types are located along the lateral margins of the river flood
pl ain and are subject to dewatering if naturally occurri ng summer
discharges are significantly reduced by the proposed hydroelectric
facility.Juvenile chinook salmon were selected as evaluation species
as they have been shown to utilize these habitats for summer rearing
(ADF&G 1983b,Schmidt et ale 1984).
The FAS was divided into three parts:1)an evaluation of invertebrate
drift;2)an analysis of the flow requirements of macrobenthos;and,3)
a confirmatory study of juvenile chinook feeding habits.The specific
objectives of the three part study were to:
1.Evaluate the available food sources in selected mainstem
affected side channel and side slough habitats and verify
their relative importance to juvenile chinook salmon;
2.Evaluate the relative importance of the contribution of
ma1nstem invertebrate drift in selected mainstem affected side
channel and side slough habitats;
3.Estimate the response of selected groups of invertebrates from
selected mainstem affected side channel and side slough
habitats to various water depths,velocities,and substrate
types;and,
4.Quantify the area of habitat usable to selected invertebrate
groups at different mainstem discharges in selected mainstem
affected side channel and side slough.
Three side channels and one side slough were selected for study between
River Mile (RM)129 and RM 142 (Figure 1).These study sites were
selected to utilize previously established IFG modelling transects
located in areas found to contain significant numbers of juvenile
chinook salmon.Data collected within the study sites included:
2
.....
Alaska
Bridge
:r-1r:...-Slough 9
,.Side Channel 21
Gold Creek
USGS Recorder 15292000
pper Side Channel II
o FAS STUDY SITES
•RIVER MILE
a
!
mile
(Approx.Scale)
Fi gure 1.Map of the mi ddl e Susti na Ri ver show;ng the four Food
Availability Study sampling sites,1984.
3
....
benthic and drift.invertebrate samples and point specific water depth,
mean column water velocity,and substrate composition.These data were
combined with existing hydraulic simulation model data to estimate the
response of invertebrate habitat to changes in discharge.In addition,
juvenile chinook salmon were collected for stomach content analyses to
verify food habitats.
Because of the 1imited number of invertebrates per unit area at each
sampling site,a somewhat different approach to grouping invertebrates
was utilized in the study over that suggested by Judy and Gore (1979).
Whereas Judy and Gore constructed preference curves for species of
benthi c invertebrates representi ng di fferent functi ona 1 groups,curves
in this study were constructed for groups of invertebrates representing
behavioral types which reflect basic habitat preference (e.g.,burrowing
organisms might prefer smaller substrate size classes).
The findings of this study should provide resource managers with the
information necessary for a better understanding of the mainstem dis-
charges require<f for the maintenance of adequate production of fish food
organisms in juvenile chinook salmon rear'ing areas •
4
....
-
.....
2.0 METHODS
2.1 Field Sampling
2.1.1 Study Site Selection
Juvenile salmon distribution and abundance studies in the middle Susitna
River have shown that juvenile chinook salmon utilize mainstem affected
side channel and side slough habitats for summer rearing (ADF&G 1983b,
Schmidt et al.1984).For this reason,four sites (Figure 1)repre-
senting a cross section of the side channel and side slough habitats
available to rearing juvenile chinook salmon in the middle Susitna River
were chosen for study.The sites selected for study were:Side Slough
9 (RM 128),Side Channel 10 (RM 134),Upper Side Channel 11 (RM 136),
and Side Slough 21 (RM 142).For purposes of this report,the Side
Slough 21 site will be referred to as the Upper Side Channel 21 Site
(i.e.,the area is located at the mouth of Slough 21 in the Upper Side
Channel 21 study site upstream of overflow channel AS).
Each of these sites are affected by mainstem discharge to varying
degrees and contain existing hydraulic simulation model (IFG-4)tran-
sects which can be used for invertebrate habitat analysis.In previous
studies,significant numbers of juvenile chinook salmon have been
captured at each location (ADF&G 1983b,Schmidt et al.1984).A com-
pletephysical description of each study site can be found in Quane et
ale (l984b).Available hydrographs,rating curves,and discharge data
for each of the study sites are presented in Appendix A.
2.1.2 Invertebrate Drift
To evaluate differences between the number of invertebrates entering
mainstem affected habitats and the number of invertebrates within
ll1ainstem affected habitats,invertebrate drift was sampled at two
locations each of the -four study sites.One pair of drift nets were
located at the head of each study site where the mainstem breaches into
the side slough or side channel,and another pair of nets were located
within the IFG modelling study area (Figures 2 through 5).
Drift nets were constructed of 500 micron Nitex netting and measured 12
x 18 x 39 inches (Figure 6).The downstream end of each drift net
consisted of a detachable collection bucket constructed of a 15 inch
section of plastic pipe with 500 micron Nitex net windows and base.
While in the water,each net was supported by two one inch diameter
steel rods that were pounded into the substrate.Four three inch chrome
rings,attached to the corners of each net frame,allowed easy setting
and removal of nets from the steel rods.
To ensure the greatest catch size,drift was sampled during the evening,
which is generally considered to be a period of increased activity for
many aquatic invertebrate taxa (Hynes 1970,Waters 1972).Each site was
sampled three times during the sampling season (Table 1).Nets were set
approximately two hours before sunset for two consecutive days at each
site.The sampling duration for each net pair was dependent on river
stage and debris load and ranged from 0.12 hours to 1.20 hours.If the
5
i 1 -"-I ~J --I e-l ,-1 1 1 1
'.~:
,e.t..
'J.
.'
':
••&.-:--;J"'.,...;.,,--t>••-;.....::.,~.-•••.....:~-;;.'~..."".-:-/.."~....
SLOUGH 9*Drift Sample Sites
~Juvenile Chinook
~SamplinQ Areel
I Benthic Sampling
Transects
o 1000
I I
FEET
(Appro.,Scol,)
B
:.1
I';''.~~
'i;.'.'~..~.,
.;
:.~,
..,
El)RM 129--RiVER
~
,W;I~.\••.
_",,_.->_:0':."';'"''-':~;....'
;;;:..,.~..
':":~''''.>//:Dry Chann.1
',-.;/....:,,;..-;;./.,.-..u "7 ...,..::)/;'"~,.)/,:;.:,.
•.0-'"
_Slough 9----.
0\
Figure 2.Map of Slough 9 showing invertebrate and juvenile chinook salmon sampling locations,June through
September,1984.
1 )1 -1 1 1 1 i i 1 I )
,,;:~
.)
;..*
~.~:'
".••~l
'.-..
NIV~N __
:.n."t.";:.;-:;;.;l:r:~..,.;I.i.-.:......"~::"'••
SIDE CHANNEL 10
*Drift Sample Site's
PA Juvenile Chinook
~Sampling Area
I Benthic Sampling
Transects
o 500
I I
FEET
(Appro •.Scale)
'-J
Figure 3.Map of Side Channel 10 showing invertebrate and juvenile chinook salmon sampling locations,
June through September,1984.
--1 j 1 1 1 I -1 1 1 i 1 1 I 1
ex>
UPPER SIDE CHANNEL II*Drift Sampling Site
f?/JJt.Juvenile Chinook
~Sampling Area
I Benthic Sampling
Transects
o 300, I
FEET
(Appro Il.Scale)
~
tt-0
~
tt-'"
..'If'.p
~
Figure 4.Map of Upper Side Channel 11 showing invertebrate and juvenile chinook salmon sampling locations,
June through August,1984.
~I l ----1 J )'--1 t'1 i 1>1 ]
SLOUGH 21*Drift Sample Sites
ITTh.Juvenile Chinook
V/JII Sampling Area...r Benthic Sampling
Transects
a 1000
I I
FEET
(Approx.Scal,)
EB RM 142
~~_""";,",$"7,._;,.;_<if"';:'',l1Z:li"""·""",,,;,,...-.--.
RiVER ---
",'_..!:~.~",.~.'11.'":.;.~.O!"'.,
..--Slough 2/-
ttfh.;.'hl"'~...__....y ._.-_"=":...•~.,!,.~"'·.~.'-t:.;··::":•.:~..",
.~~'!•••
sus/rNA
,l..·'··:··..•..•·•••..:.,:•••_.:•.~...~,.'-~
••-:~:.~,:••;.:.c-.:!-:j..,
5 7
..----
AS
\0
Figure 5.Map of upper Side Channel 21 and Slough 21 showing invertebrate and juvenile chinook salmon
sampling locations,June through September,1984.
Benthic Sampler
1----14 11-----t
'Til1
.....----15 ..·----t
~:...,.
loJI------30 "--1
/500 Micron Nilex
~~~r::=:::L.._
~,
Drift Sampler
Tr
Nitex
............-..,:::::.:.:::...,
...----1 11 Steel Post
Figure 6.Invertebrate sampling gear used in the Food Availability
Study,1984.Adapted from Merritt and Cummins (1978).
10
l 1 't l'}~1 "I -1 1 J I
Table I,Food availability study sampling dates,middle Susltna River,Alaska,1964.
June July August September
Sampling Type 7 6 9 10 11 12 13 14 24 25 26 27 26 6 7 6 9 10 11 12 13 14 9 10 11 12 13 14 15 16 23 24 6 9 10
SLOUGH 9
Benthic X X
Drift X X X X X X
Juvenile Chinook X X X
Temperature X X X X X X X X
Turbidi ty X X X X X X X X
SIDE CHANNEL 10
Benthic X X
Drift X X X X X X
Juvenile Chinook X X X
Temperature X X X X X X X X
Turbl dl ty X X X X X X X X
I-'UPPER SIDE CHANNEL 11
I-'
Benthic X X
Drl ft X X X X X X
Juvenile Chinook X X X
Temperature X X X X X X X X
Turbidity X X X X X X X X
SlOE CHANNEL 21
Benthic X X
Drift X X X X X X
Juvenile Chinook X X X X
Temperature X X X X X X X X
Turbl dl ty X X X X X X X X
-
-
side slough or side channel being sampled was not breached,only the
IFG-4 drift sampling location was sampled.
Water velocity·and depth were measured in the center of each net opening
at the beginning and end of each sampling period using a Marsh/McBirney
electrical current meter and wading rod using procedures described in
ADF&G (1984).The two depth and velocity measurements for each net were
averaged and used to calculate the total volume (ft3 )of water filtered •.
2.1.3 Benthic Invertebrates
Benthic samples were collected along existing IFG-4 modelling transects
at each sampling site twice during the open water season to determine
invertebrate habitat preferences (Table 1).The number placement of
samples taken at each study site during a sampling date was determined
by the variety of microhabitat conditions available (i.e.,the variety
of depth,velocity,and substrate combinations present).
Benthic samples were taken with a 25 inch high 1.08 ft 2 cylindrical
benthic sampler constructed of aluminum and covered with 500 micron
Nitex netting (Figure 6).The same detachable collection bucket used on
the drift nets was used on the benthic sampler.
Benthic samples were taken by forcing the sampler into the substrate to
a depth of four inches and agitating the enclosed substrate by hand
until all suspended materials were washed downstream into the collection
bucket.When samplingl~rge substrates such as boulders,the sampler
was placed on the boulder surface and the substrate was scraped by hand
to remove any invertebrates present.Similarly,the uppermost layer of
medium sized substrates (ego rubble,or cobble)were dislodged and all
surfaces were scraped to remove invertebrates.
Point measurements of water depth and mean column water velocity were
recorded prior to taking a benthic sample using a Marsh/McBirney elec-
trical current meter and wading rod using methods described in ADF&G
(1984).In addition,substrate type was visually determined while
taking each sample using a thirteen class ranking system (Table 2).The
location of each sample was determined by reading a fiberglass measuring
tape stretched between the headpins of the IFG-4 modelling transect
being sampled.
Additional benthic samples were collected in April,May,September,and
October for determining invertebrate development using a kick screen
similar to that described in ADF&G 1983a.These samples,however,were
not used in the development of invertebrate suitability criteria.
2.1.4 Juvenile Chinook Salmon
To compare the diet of juvenile chinook salmon with the composition of
invertebrates in drift and benthic samples,juvenile chinook salmon were
captured for stomach content analysis at each side channel and side
slough study site.This infonlation was used to supplement previously
collected data on juvenile chinook salmon diet in the middle Susitna
River (ADF&G 1978,ADF&G 1983b).
12
--
......
Table 2.Substrate classification
substrate composition at
(Vincent-Lang et a1.1984)•
scheme utilized to evaluate
each benthic samp1 i ng point
IFG Code Substrate Category Size (inches)
""'"1.0 si1 t less than 1/32I
2.0 silt -sand
3.0 sand 1/32 -1/8
4.0 sand -small gravel
5.0 sma 11 gravel 1/8 - 1
6.0 small gravel -large gravel
7.0 .large gravel 1 - 3
8.0 large gravel -rubble
9.0 rubble 3 - 5
10.0 rubble -cobble
11.0 cobble 5 -10
12.0 cobble -boulder
13.0 boulder greater than 10
..-
I
....13 .
-I
-
-
Study sites were electrofished three times during the field season using
a Coffelt (model no.BPIC)backpack electroshocker (Table 1).From each
catch,four to seven juveniles were collected for future stomach content
analysis.A small incision penetrating the body cavity was made
superior to the pelvic girdle on the fish's left side to ensure adequate
preservation of its stomach contents.The fish were then stored intact
in 70%ethyl alcohol (ETOH).
2.1.5 Turbidity
Water samples for turbidity measurement were taken during both drift and
benthic sampling at each study site.All samples were stored in 125
milliliter (ml)Nalgene bottles,kept cool in a darkened storage con-
tainer,and analyzed within 72 hours of collection.Turbidity was
measured in Nephalometric Turbidity Units (NTU)with an H.F.Instruments
ORT -15B Portable Turbidimeter foll owing proc.edures outl ined in AOF&G
(1984).
2.2 Laboratory Analysis
2.2.1 Sample Storage and Handling
All invertebrate samples were placed in polyethylene bags and preserved
with 70%ETOH.Rose Bengal dye was added to the alcohol to dye inverte-
brates for easy sorting.Invertebrates were hand sorted from debris and
stored in glass vials containing 70%ETOH for later identification and
enumeration.
Juvenile chinook salmon preserved for stomach content analysis were
measured for total length and their stomachs removed by making cuts at
the anterior esophagus and pyloric sphincter.After removal,stomachs
were stored in glass vials containing 70%ETOH for later invertebrate
identification and enumeration.
2.2.2 Invertebrate Identification and Enumeration
Invertebrates from benthic,drift,and juvenile chinook stomach samples
were identified to the family taxonomic level and counted.If identi-
fication to the family level was not possible,invertebrates were
identified to order.
Invertebrates from juvenile chinook stomachs were counted using whole
individuals when possible or body parts if items were partially digested
or dismembered.Head capsules were used to count chironomid larvae
(midges),whereas the head and thorax regions were used to count dismem-
bered plecopterans (stoneflies)and ephemeropterans (mayflies).Other
dismembered invertebrates were counted by piecing together identifiable
body parts to estimate the ki nd and number of i ndivi dua 1s present.
Unidentifiable parts were not counted.Keys used to identify organisms
include:Johansen and Thomsen (1934),Usinger (1956),Edmunds et ale
(1976),Bauman et al.(1977),Wiggins (1977),Merrit and Cummins (1978),
Pennak (1978),and Borror et al.(1981).
14
where:
-
-
2.3 Data Analysis
2.3.1 Invertebrate Drift
In this study,density (i.e.,number of individuals per unit volume of
water),reported in English units (e.g.,cubic feet and cubic yards),
was used to describe the abundance of drifting invertebrates in samples.
Densities were standardized by dividing the number of individuals in a
taxa or group by the volume of water filtered.The relative density of
an organism or group at a particular sample site was determined by
placing the standardized mean density of that organism or group into one
of four classes representing different orders of magnitude.The classes
used were:Rare (O.001-0.009/yd 3 ),Sparse (O.010-0.099/yd 3 ),Common
(0.100-0.999/yd 3 ),and Abundant (1.000-9.999/yd 3 ).
The differences in drift density at head and IFG-4 sampling locations
within study sites was evaluated by placing sorted and identified
invertebrates into eight taxanomic groups.The groups were:Collembola
(spri ngta i1 s),Ephemeroptera.(mayfl i es),P1 ecoptera (stonefl i es),
Trichoptera (caddisf1ies),Diptera larva (flies),Diptera adults,Other
Insects,and Other Invertebrates.Multiple regression analysis was then
used to determine the relationship that the quantity of invertebrate
drift present at head sites has to that present at IFG-4 sites.The
dependent variable in this analysis was drift numbers at the IFG-4 site
and the independent variables were drift numbers at the head sites,
volume of water filtered through nets at head sites,and volume of water
filtered through nets at IFG-4 sites.
The original data were transformed using a logarithmic transformation
(log)to reduce variance and skewness (i.e.,log [x+1]where x equals
numb!r of individuals)following procedures deScribed in Steel and
Torrie (1960).The general linear model tested was:
y =60 +61x1 +~x2 +63 x3 +£
6 =intercept term;6~=regression coefficients (1,2,3);
x'=transformed (log [x+1])numbers of grouped
1 drift invertebrat~s collected at the head site;
x2 =transformed (loge [x])volume of water filtered
for drift sample collected·at the head site;
x3 =transformed (log [x])volume of water filtered
for drift sampleecollected at the IFG-4 site;
y =transformed (loge [x+1])numbers of grouped
drift invertebra~es collected at the IFG-4
site;and
£=Error term
The null hypothesis in this evaluation was:Numbers of drifting indi-
viduals in invertebrate groups at IFG-4 sites was not dependent on
(related to)the numbers of drifting individuals in invertebrate groups
at head sites,volume of water filtered at head sites,or volume of
water filtered at IFG-4 sites.
15
To determine if the observed variations in the drift numbers at IFG-4
sites were due to any of the independent variables and not due to chance
alone,an analysis of variance (ANOVA)was performed.The hypothesis
tested was:
H :S =S =6 =0H~:si F 6~F 6~F 0
The F test criterion was defined as:
F =mean square error due to regression
residual mean square error
To determine if the partial regression coefficients had true values
greater than zero,the Student 1 s t test was app 1;ed (Steel and Torri e
1960)•The hypotheses tested in th i.s case were:
Ho:)1 =0,62 =0,S =0
HA: 61 F 0,62 F 0,S~F 0
The test criteria are defined as:
The probability level used in both the F test and the Student's t test
was a=0.05.
To depict the'relationship between drift density 'at IFG-4 sites and
drift density at head sites,the drift data (counts)were plotted on a
two dimensional cartesian plane.The counts were plotted in three ways:
1)head counts versus IFG-4 counts for all samples collected,2)head
counts versus IFG-4 counts for each sampling month,and 3)head counts
versus I FG-4 counts for each samp 1i ng 1ocati on.For these plots,the
number of invertebrates in each group was standardized and multiplied by
1,000 to estimate the number of organisms caught per 1,000 cubic feet of
water filtered through each net..Standardized data were transformed
using the natural logarithm transformation (loge [x+1]).
2.3.2 Benthic Invertebrate
A
6.,
-
=t =-:---SA
Si
estimate of the partial regression coefficients
standard error of the estimate of the partial
regression coefficient
2.3.2.1 Standing Crop Estimation
Benthic samples were used to estimate the standing crop of benthic
invertebrates present at each of the four study sites.Mean densities
(i.e.,average number of individuals per unit area)reported in English
units (e.g.,square feet and square yards),were used to describe the
abundance of individuals.Benthic invertebrates were first identified
and counted for each sampl e.These counts represented the number of
16
,....,
organisms or groups occurring in an area 1.08 foot square (ft2 ).The
average number of organisms or groups per unit area was calculated by
dividing the total number of an organism or group in all samples by the
number of samples.The relative density o~an organism or group at a
particular study site was then determined by placing the calculated mean
density of that organism or group into one of four classes representing
different orders of magnitude.The classes used were:Rare (0.1 -
0.9/yd 2 ),Sparse (1.0 -9.9/yd2 ),Common (10.0 -99.9/7d 2 ),and Abundant
(100.0 -999.9/yd 2 ).
The diversity (HI)of the benthic invertebrate community in riffle,run,
and pool habitats in the side channels and side sloughs was calculated
using the Shannon-Weaver diversity index (Poole 1974).The evenness
(JI)of the benthic community was also calculated using an index which
incorporates the value of HI.Both insect taxa and non-insect taxa were
used in the calculation of the indices.The formulae for the
Shannon-Weaver.diversity index and the eveness index are shown in
Appendix D.
2.3.2.2 Suitability Criteria Development
Weighted habitat criteria representing a particular species/l ife phase
preference for a particular habitat variable were developed for benthic
food organisms for input into a habitat simulation model used to calcu-
late usable benthic invertebrate habitat area.Due to the small numbers
of many of the benthic food taxa sampled and problems associated with
interpreting numerous weighted habitat criteria-for each taxa,weighted
habitat criteria were only developed for .four behavioral types of
benthic food organisms:burrowers,sprawlers,swimmers,and clingers.
The placement of a particular invertebrate taxa (i.e.,family)into one
of these behavioral types was based on information compiled by Merritt
and Cummins (l978)who give a general description of.the locomotive
behavior of invertebrates at the family and sub-family level.In this
study,the sub-family level of classification was referred to only when
large families of invertebrates were being categorized.This was
necessary because of the possibility of the presence of family members
being of a different behavioral type than that described for the family
as a whole.For example,when assigning Chironomidae to burrowers,the
sub-families Deamesinae and Orthododinae were considered since these are
the principle sub-families present in Susitna River samples (Milner
pers.COI11l1.1984).These two sub-famil ies were comprised primarily of
burrower behavioral types.Table 3 lists each behavioral group,its
general description,and the invertebrate taxa belonging to each
category.
Weighted habitat criteria are typically expressed in the form of habitat
curves which describe the relative usability of different levels of a
particular habitat variable for a parti,cular species/life phase,with
the peak indicating greatest usability and the tails tapering towards
less usable values.Curves are typically developed for each habitat
variable considered to influence the selection of habitat for the
speci es/l ife phase of interest.Three types of habitat curves are
typically constructed:utilization,preference,and/or suitability.A
detailed description of each curve type and its usage in habitat simu-
lation models is presented in Vincent-Lang et al.(1984).
17
Table 3.Invertebrate taxa grouped by behavioral type (Merritt and Cummins~1978).
-I
-
Behavioral Type
Burrowers
Clingers
Sprawlers
Swimmers
Description
.Inhabiting the fine sediments of streams (pools).
Some construct discrete burrows which may have sand
grain tubes extending above the surface of the
substrate or the individuals may ingest their way
through the sediments (examples:Diptera~most
Chironominae~Chironomini-"blood worm lt midges).
Representatives have behavioral (e.g.~fixed
retreat construction)and morphological (e.g.~
long~curved tarsal claws,dorso-ventral flattening
and ventral gi 11 s arranged as a sucker)adaptations
for attachment to surfaces in stream riffles
(examples:Ephemeroptera,Heptageniidae;
Trichoptera,Hydropsychidae).
Inhabiting the surface of floating leaves of
vascular hydrophytes or fine sediments,usually
with modifications for staying on top of the
substrate and maintaining the respiratory surfaces
free of silt (examples:Ephemeroptera~Caenidae).
Adapted for Itfishlikelt swillllling in lotic or lentic
habitats.Individuals usually cling to submerged
objects,such a~rocks (lotic riffles)or vascular
plants (lentic),between short bursts of swillllling
(examples:Ephemeroptera in the families
Siphlonuridae,Leptophlebiidae).
18
Invertebrate Taxa
Tipulidae
Chironomidae
Psychodidae
Chloroperlidae
Ephemerellidae
He ptagen ii dae
Hydropsychidae
Perl odi dae
Rhyacophilidae
Simuli idae
Taeniopterygidae
Capniidae
Limnephi 1idae
Nemouridae
Baetidae
Sfphlonuridae
-
In this report,utilization curves were modified using pertinent litera-
ture and professional judgement to define weighted habitat suitability
criteria for selected behavioral groupings of benthic invertebrates.
Weighted habitat suitability criteria were developed for the three
habitat variables considered of greatest importance to benthic inverte-
brates:depth,velocity,and substrate.Due to the limited data base
that coul d be used for the development of wei ghted habitat suitabi lity
criteria,benthic invertebrate data were pooled from all sites and both
benthic sampling periods.
The first step in the development of weighted habitat suitability
criteria involved the construction of utilization curves for depth,
velocity,and substrate.Because depth and velocity were measured in
the field to the nearest 0.1 ft and 0.1 ft/sec,respectively,the
initial utilization plots were constructed using intervals having these
values.However,since sample numbers were low within each of the
measurement velocity and depth intervals and variances were high,
intervals were grouped (Table 4).Grouping of intervals was done by
best visual fit of the data by considering the relative number of
samples representing each interval,the number of irregular fluctuations
present among intervals,and the accuracy of the depth and velocity data
collected.
Substrate was determined in the fiel d according to numbered di screte
substrate classes (e.g.,silt,sand,gravel,etc.)defined in Table 2.
Since sample numbers were low within these substrate classes and vari-
ances were high,substrate classes were grouped for the construction of
the .initial utilization plots (Table 5).As for depth and velocity,
grouping of classes was done by best visual fit of the data by con-
si dering the rel ative number of sampl es representing each cl ass,the
number of irregular fluctuations present among the different classes,
and the accuracy of the substrate data collected.
Relative utilization for each of these habitat variables was then
derived by taking the total number of individuals within each new inter-
val range of depth,velocity,or substrate cl ass and dividing by the
total number of samples having that same depth,velocity,or substrate
range value.The resulting means (mean number of type individuals/-
sample)were plotted against their corresponding depth,velocity,and
substrate range to provide iJtil ization curves of the three habitat
variables for all four behavioral types.To calculate a utilization
index of 0.0 to 1.0 for the ranges "in each histogram,each mean was
divided by the largest mean determined on that histogram.In addition,
a 95%confidence interval for the means was calculated for each range in
the histograms.
Weighted habitat suitability criteria were then developed for each
habitat variable for each of the four behavioral types based on the
developed utilization curves,as modified using pertinent literature and
professional judgement.In general,for ranges where utilization data
were present,the utilization curve was used to define weighted habitat
suitability criteria.For ranges which there was no utilization data,
pertinent literature,professional judgement,and the general trends in
the utilization data were used to define weighted habitat suitability
19
Table 4.Depth and velocity increments used for suitability criteria
development
Increment Number
Depth
(ft)
Increment Range
Velocity
(ft/sec)
Increment Number ,Increment Range
....
i
....
1
2
3
4
5
0.0 -0.4
0.4 -0.8
0.8 -1.2
1.2 -1.6
1.6 -2.0
1
2
3
4
5
6
7
8
9
10
11
0.0
0.0 -0.2
0.2 -0.4
0.4 -0.6
0.6 -0.8
0.8 -1.0
1.0 -1.2
1.2 -1.4
1.4 -1.6
1.6 -2.0
2.0 -2.6 '
Table 5.Substrate class groupings used for suitability criteria
development.
'-,Class Number Class Range Description
1 1.0 -4.0 Silt -Sand/Small Gravel
2 5.0 -7.0 Small Gravel -Large Gravel
3 8.0 -10.0 Large Gravel/Rubble -Rubble/Cobble
4 11.0 -13.0 Cobble -Boulder,-
-
20
--
-
criteria.Literature used to help in determining weighted habitat
suitability criteria included:Kennedy 1976,Newell 1976,Bjornn et al.
1977,Gore 1978,Harris and Lawrence 1978,Hubbard and Peters 1978,
Surdick and Gaufin 1978,Judy and Gore 1979,White et ale 1981,and
Anderson 1982.
Mean water column velocities were measured in this study as opposed to
point velocities at the substrate surface so as to validate the use of
the resultant weighted habitat suitability criteria in the HABTAT model
which uses mean water column velocities to project usable habitat area.
Use of mean water velocities is consistent with that of other
researchers involved with habitat simulation modelling for benthic
invertebrates (Judy and Gore 1979).
2.3.2.3 Weighted Usable Area
The HABTAT habitat simulation model of the IFG (Milhous et al.1981)was
used to project wei ghted usabl e area (WUA)of benthic invertebrate
habitat at each site.To calculate WUA,weighted habitat suitability
criteria for depth,velocity,and substrate for each behavioral group
were inputed using the standard calculation technique to calculate a
joint preference factor (Judy and Gore 1979)along with the IFG-4
hydraulic simulation modelling details from 1983 for each study site
(Vincent-Lang et al.1984)into the HABTAT habitat simulation model.
Use of the physical simulation models developed during the 1983 open
water.field season (Vincent-Lang et al.1984)was considered valid in
this analysis although specific changes in channel geometry and
morphology may have occurred at a parti cul ar study site as such changes
probably reflect a dynamic,but generally stable equilibrium.There-
fore,such changes are believed to exert only a limited influence on the
long-term habitat availability at a study site,validating the use of
the models i-n-this analysis.A detailed explanation of the steps
involved in calculating WUA is provided in Vincent-Lang et al.(1984).
Gross surface area at each study site and WUA for each behavioral group
at each study site were projected over the range of site flows from
5.0-600.0 cfs at Slough 9,5.0-100.0 cfs at Side Channel 10,5.0-250.0
cfs at Upper Side Channel U,and 5.0-400.0 cfs at upper Side Channel
21.Resul tant WUA projecti ons were then plotted as a function of site
flow to graphically show the relationship between site flow and WUA for
each behavioral group.In addition,gross surface area was plotted on
each respective figure.
The relationships between WUA and gross surface area to mainstem dis-
charge were also plotted for periods when the site flow was directly
controlled by mainstem discharge.Additional plots using -an expanded
WUA scale were constructed for each site to better depict and compare
trends of WUA as a function of mainstem discharge at and between study
sites.The x-coordinate values on these plots were derived using
site-specific flow/mainstem discharge rating curves presented in
Appendix A.
21
.....
-
-
2.3.3 Invertebrate Larval Development
The amount of growth or development of the larva of hemimetabolous
insects was determined by visual inspection of the amount of wing
development within the wing pads.Three categories of larvae were
determined:early instar (i.e.,the insect shortly after hatching from
the egg),middle instar,and late instar (the insect shortly before
emergence as adult).If no wing pads were discernible or if no wing
development was discernible within the wing pads,the insects were
considered to be in the early instar stage.Middle instars were con-
sidered to be individuals having wing pads in which the developing wings
had the appearance of venation.If wing pads contained flight wings
which appeared near full development,the insects were considered to be
in the late instar stage.Wing pads in this last stage of development
appeared dark as a result of the tight folding of the flight wing inside
the pads.
2.3.4 Juvenile Chinook Salmon
The stomach content data from juvenile chinook salmon were pooled for
all sites and sampling dates and grouped into the eight taxonomic
categories listed in Section 2.3.1.Percent composition of each cate-
gory was determined and displayed as pie diagrams.In addition to the
taxonomic groupings,the benthic aquatic insects found in the juvenile
chinook stomachs were grouped by behavioral type as shown in Table 3.
The percent composition of each behavioral group was determined and also
represented as pie diagrams.In addition to the pie diagrams,juvenile
chinook salmon stomach content data were presented in the form of bar
diagrams.For these diagrams,all sites were pooled for comparison of
the relative contribution of the different taxonomic groups on the four
sampling dates.
Benthic invertebrate and invertebrate drift data were also presented in
pie diagrams for comparison with the juvenile chinook stomach content
data.Pie diagrams of the benthic and drift data were made with the
same eight taxonomic groupings and the four aquatic insect behavioral
types.
22
-
.-
,....
3.0 RESULTS
3.1 Invertebrate Drift'
Six orders,representing 30 families of aquatic and semi-aquatic in-
sects,and eight orders not identified to the family level were collect-
ed within the four study sites during the 1984 open water study period.
In addition,eleven non-insect aquatic and non-aquatic groups were also
collected (Appendix Table 8-1)..
The most frequently occurring invertebrate groups in drift samples were
di pteran fl i es and ephemeropterans (mayfl i es)wi th Pl ecopterans
(stonefl ies)being the third most frequently encountered insect group
(Appendix Table B-2 through 8-5).Chironomid flies and baetid mayflies
made up the majority of individuals in Diptera and Ephemeroptera,
respectively,whereas no family was dominant in Plecoptera.Chironomids
were relatively abundant throughout the entire sampling period while
ephemeropterans were relatively common only in early June.Plecopterans
were more common in early August than in early June.The relative
density of these three insect groups was generally greater at head
sampling sites than at IFG-4 sampling sites (Table 6).
Scatter plots,showing the linear relationship between drifting inver-
tebrates grouped as Collembola,Ephemeroptera,Plecoptera,Trichoptera,
Diptera larvae,Diptera adults,Other Insects,,and Other Invertebrates
are shown in Figures 7 and 8.These two figures show the relationships
of drifting invertebrates under breached conditions.The plots reveal in
all cases that the numbers of individuals at IFG-4 sites increase as the
number of individuals at head sites increase.The slope of the
regression equation for all plots,however,suggest that proportionately
fewer invertebrates were found in the drift at IFG-4 sampling sites than
at head sampling sites.Coefficient of determination values (r2 )for
the plots ranged from 0.14 to 0.89 with the upper Side Channel 21 data
having the lowest .value.This sampling location was frequently un-
breached or at initial breaching during sampling periods resulting in
few drift samples being taken at this location.
The results of the multiple regression F test indicated that the varia-
tion in drift numbers at the IFG-4 sites (y)could be "expla"ined"by the
variation in drift numbers at the head sites (x ),volume of water
filtered at head sites (x 2 ),and volume of water ffltered at the IFG-4
sites (x ).However,the resul ts of the Student 1 s t tests indicated
that the3 regression coefficient (S2)for x,was not si gnificantly
different from zero.Accordingly,a new g~neral linear model was
evaluated which did not utilize x2•The new model was:
y =BO +Sl xl +B3x3 +€
where the symbols are the same as defined in section 2.3.1.The F test
for this model indicated that the variation in drift numbers at the
IFG-4 sites (y)could be "explained"by the variation in drift numbers
at the head sites (xl)and the volume of watered filtered from samples
at the IFG-4 si tes (x ).The Student 1 s t test resul ts for thi s model
indicated that 61 and l3 were significantly different from zero (at a =
23
~Table 6.Relative density of invertebrate drift per cubIc yard of water by site and drift net
location,June through August 1984,Middle 5usitna River,Alaska.R=Rare
(0.001-0.009/yd 3 ),S=5parse (0.010-0.099/yd 3 ),C=Conunon (0.100-0.999/yd 3 ),A=Ab~ndant
(1.000-9.999/yd 3 ).
Upper
Slough 9 Side Channel 10 Side Channel 11 Slough 21
Site Head IFC-4 Head I FC-4 Head IFC-4 Head IFC-4
INSECTA
Protura -R
Collembola R
Isotomfdae 5 5 5 5 C 5 5 R-POdurfdae R R R 5 R
5minthuridae R R R R R 5 R
TOTAL Collembola 5 5 5 5 C S C R
~t(i!f!!I:IfS,
Ephemeroptera R
Baetidae 5 S C 5 A C R
Ephemerellidae 5 5 5 S 5 R 5 R
Heptageniidae 5 5 5 5 5 5 5 R
5i phlohurf dae 5 5 5 R 5
TOTAL Ephemeroptera 5 5 C 5 A C 5 R
r-
Plecoptera 5 5 5 5 R
Capniidae R R R R R R
Chloroperlidae R R 5 R 5 5
Nemouridae R 5 R 5 5 R
Perlodidae 5 R 5 R 5 R 5 R
Pteronarcidae R
Taeniopterygfdae 5 5 R R
TOTAL Plecoptera 5 5 5 5 5 5 5 5
Psocoptera R R R R R
.....Thysanoptera 5 5 R 5 5 5
Hemiptera R 5 5 R R R R R
Homoptera 5 R 5 R 5 5 5
Neuroptera R 5
Coleoptera 5 5 R 5 5 5 5 R
Dytiscfdae R R
Hydrophilidae R
TOTAL Coleoptera.5 5 5 5 5 5 5 R
Trichoptera 5 5
R R 5
Clossosomatidae R R
Hydropsychidae 5 R 5 5
R R
Li mnephi 1i dae S 5 R R R R
Rhyacophilidae .5 R
TOTAL Trichoptera 5 5 5 5 5 5 R-Lepidoptera R R R R 5 5 R
24'
r-
Table 6 (Continued).
Upper
Slough 9 Side Channel 10 Side Channel 11 Slough 21
Site Head IFC-4 Head fFC-4 Head IFG-4 Head IFG-4
l"·'"Diptera S R S S S S R
Ceratopogonidae R R R S S R S S
Chironomidae A C A C A A C A
Culcidae R
Dixidae R R
Empididae R S S S S S C R
Muscldae R R R
Psychodidae R R R R
Simuliidae C S C C C S S R
Stratiomyidae R
Syrphidae R R
,""Tipulidae R R S R S S S R
TOTAL Diptera A C A A A A A A
Hymenoptera S S S S S S C C
HYDROZOA R
NEMATODA S R R R
OLI GOCHAETA S S C S S S S
CRUSTACEA
Cladocera S S R R
Podocopa R R S R R
Eucopepoda S S S S R S
~,Amphipoda R R
TOTAL CRUSTACEA S S S S S S R
ARACHNIDA
Araneae R R R R S R R
Acari S S S S S S S
TOTAL ARACHN IDA S S S S S S S.-
CHILOPODA R
CASTROPODA R R
-
25
)1 --1 1 1 1 1 -~
I ~1 J 1 ])
HEAD VERSUS IFG DRIFT SAMPLES
IoIATCHED BY TAXA-SL II $AMPLES IoIATCHED BY TA)(A-SC 10 $AMPLES
5 '1
4 ":::::1 •
'+0 '+•..
1:0 ~
0 qpD .....
~"a:;,
DO
~0 ~"§0 §
:::.~"'a ~~
~D ~
,~/'0
Z
"0 '1 .0.7411 .0.17 !:'1 ·0.8111-0.17!!:••00 D ,2·0.73 III a ,2.0.89
n ·48 "EI n •24BElD
0""-
0 0
0 2 •II 0 2 ••
HEAD NOS./IOOO eu It [In(..+I)]HEAD NOS'/1000 eu It [In(..+I)]
N
m
,..ATCHED BY TAXA-USC II $AMPLES "'ATCHED BY TAXA-SC 21 SAUPLES
5 I I 5 I
'1 -0.05 ••0.39
,2 •O.14
0 .J n •16
~
4 0 :::::1
0 '+•·o 00 ..r !
;:"no 0 a:"~o 0 ~
""§0 §D D 0
"-~G z 2 1 0
vi D .~0 0 D D DZ
"00'111 Y -0.86.-0.09 ~!!:•I ..0
0 0 0 ,2.0.89
o.tKe i
0 n -48 I 01 0
0
0
i I i i •i •I II •i i
0 2 4 II 0 2 4 II
HEAD NOS./IOOO eu It [In(.+1)]HEAD NOS./IOOO eu It [In(.+')]
Figure 7.Scatter plots of standardized drift densities (no/1000 feet 3 of water)of eight inver-
tebrate groups,head numbers vs.IFG-4 numbers.Densities are transformed.loge (x+l).
))]J J J 1 J J E 1 1 1 -1 -1
HEAD VERSUS IFG DRIFT SAMPLES
IoAATCHED BY TAXA-ALL SAMPLES
......TCHED BY TAXA-JULY SAMPLES
IoAATCHED BY TAXA-JUNE SAMPLES
:I ,.1------,-------
y 00.45 ••0.26
r 2 ·0.59
~4.J n·48 D
+i I DOD
';J 1 p D
a
§
~2
i
l:.~..D pD D
DID P D DaD
0,II..i
o Z 4 •
HEAD Nos./IOOO (;u II [In(H I)]
lol...TCHED BY T...XA-...UGUST SAlolPLES
•
a
D
a
D
lJ
y -0.59 ••0.40
r 2 .O.65
n 0136
"
lJ
a
Z 4
HEAD Nos./IOOO cu II [In(o+l))
a
a
"
""
a '!P"
a a
a
Dg
o8 a 1i ...
a 000 qf'tJ "
B&9 lJ QJ
"
"
:I
......4..
i
::)
~
U
§
~2
~
~
0
0
N......
Z 4
HEAD NDS./l000 cu II [In(.+1)]
a llJ
lJ
D
•
a
lJ
y 00.65 ••0.24
r 2 -0.84
n -32
lJ
a
lJ
DlJa
D
lJDD
D
D,r
lJ lJ
lJ
:I :I
D
~4 ~4
~..a +••!c.::.
::J DD ::J
~D ~u
§
Po
§
.:::.2 lJ ~Z
g "I)~
Z Z
~""8 •O.75 ••0.30 g1ay
r 2 -O.72
of n -56 I ora a.,.•I i I i
0 Z 4 •0
H~NOS./I OO~cu It [In(.+In
Figure 8.Scatter plots of standardized drift densities (no/lOOO
invertebrate groups,head numbers vs.IFG-4 numbers.
1age (x+l).
feet 3 of water)of eight
Dens ities are transformed
.:;'
F"
i
0.05).Accordingly.at mainstem discharge levels which exceed con-
trolling breaching values.there does appear to be a relationship
between composition and abundance of the drift at the IFG-4 sites versus
that at the head sites.The specific details of the general linear
models summarized above are presented in Appendix C.
On 14 occasions.an invertebrate group was found only at the IFG-4 or
the head sampling site during sampling periods.·This phenomenon oc-
curred among the groups Collembola.Ephemeroptera.Plecoptera.
Trichoptera.Diptera Larvae.and Other Invertebrates at least once at
each of the four sampling reaches.
The density and rate of drift among the eight invertebrate groups is
shown in Appendix Table B-6.This table includes densities of drifting
invertebrate groups and rates of dri ft under breached and unbreached
conditions.In general.the densities of drifting organisms and rates
of drift were higher at head sampling sites than at IFG-4 sampling sites
during periods of breaching.However.the rate of drift at the head or
IFG-4 site was~in some instances.lower or higher than expected for the
corresponding density for drifting organisms in the water columns.For
example.in the Total Invertebrates category at the head sampl ing site
in Slough 9 during the June 7-14 sampling period there were 1.49 orga-
nisms per cubic yard of water and a corresponding rate of drift of 11.98
organisms per minute.In comparison.during the August 9-16 sampling
period the density of drifting organisms in a cubic yard of water was
3.03 organisms but with a lower corresponding drift rate of 8.91 orga-
nisms per minute (Appendix Table B-6).In another instance;while the
density and rate of drift of invertebrates in the Total ·Invertebrates
category at the head site of Side Channel 10 were both higher than that
at the IFG-4 site during the June 7-14 sampling period.only the density
measure was higher during the July 7-14 sampling period (Appendix Table
B-6).The reason for this i·s that.though two equal volumes of wa~er
may have the same number of organisms.the rate at,which the organisms
contained within those volumes of water that pass a point will be
different if the velocities of the water are different.
3.2 Benthic Invertebrates
Benthos at the four study sites was dominated by aquatic insects (73%)
and oligochaete worms (24%).The remaining 3%of benthos was made up
primarily of fl atwonns (Turbell aria).nematodes.crustaceans.and mites
(Acari).with gastropods (snails)and pelecypods (clams)being inci-
dental.In all ~six orders of aquatic and semi aquatic insects and
seven classes of non-insects were identified (Appendix Table B-1).
The relative abundance of benthic invertebrates at study sites is shown
in Table 7.The seasonal variation in numbers of invertebrates is
indicated in Appendix Tables B-7 through B-I0.II)general.higher
numbers of benthic invertebrates were present in study sites during late
August and early September (late summer)than during late June and early
July (early summer).Ephemeropterans and dipterans were the most common
benthic invertebrates in early summers whereas plecopterans and
dipterans were the most common groups in late summer.Fewer dipterans
were present in benthic samples in early summer than in late summer.
28
Table 7.Relative density of benthic invertebrates per square yard by site~June through
September 1984~middle Susitna River Alaska.R=Rare (O.1-0.9/yd2)~S=Sparse
(1.0-9.9/yd2)~C=Common (10.0-99.9/yd2)~A=Abundant (100.0-999.9/yd2 ).
"...
Slough 9 Side Channel 10 Upper Side Upper Side
RM 128.3 RM 133.8 Channel 11 Channel 21
i~RM 136.0 RM 141.8
INSECTA
Collembola
Isotomidae R R R
Ephemeroptera
Baetidae S S S S-Ephemerellidae S R S R
Heptageniidae S S S S
Siphlonaridae R R R
TOTAL Ephemeroptera S S C C
Plecoptera
Capniidae S C S R
Chloroperlidae S S S S
Nemouridae R R S S
Perlodidae S S S S
Taeniopterygidae S R R
.JlSlolml
TOTAL Plecoptera C C C C
Coleoptera
Dytiscidae R
I"'"Trichoptera
Hydropsychidae R
Hydroptilidae R
Limnephilidae S S R C-Rhyacophilidae R S
TOTAL Trichoptera S S S C
~
Diptera-
Ceratopogonidae R R
Chironomidae C C C A
Empididae R S R S
Muscidae R
Psychodidae R R
Simuliidae R R R R
Tipulidae R S R S
TOTAL Oiptera C C C A
TURBELLARIA S S
,.-
NEMATODA R R R R
OLICOCHAETA C S C A
CRUSTACEA
Cladocera R
Eucopepoda R R R
Podocopa R
TOTAL CRUSTACEA R R R R
ARACHNIDA
Acari R R R S
GASTROPODA R
PElECYPODA R
29
Upper Side Channel 11 and upper Side Channel 21 typically had the
hi ghes~numbers of benthi c invertebrates present in the benthos.The
most common benthic groups at these sites were dipterans and oligo-
chaetes (Appendix Table B-8 and B-10).
Chironomid midges,oligochaetes,capniid stonef1ies,and baetidand
heptageniid mayflies were the most common benthic invertebrate families
at the four study sites.High numbers of baetids and heptageniids were
present in ea r1y summer,whereas capn;ids were most abundant in 1ate
summer.The highest numbers of chironomids occurred in late summer
(Appendix Tables B-7 through B-I0).
The mean density of benthic invertebrates commonly preyed on by juvenile
salmonids are presented by behavioral type,according to macrohabitat
(i .e.,slough or side channel)and microhabitat type (i .e.,pool,
riffle,or run)in Figure 9.In general,the data showed that side
slough macrohabitats had higher densities of benthic invertebrates than
side channel macrohabitats.The data also showed that riffles were the
only microhabitat type in which all four behavioral types were present
in densities over five individuals per square yard.Pools had the least
number of behavioral typ~s.Burrowers,comprised primarily of chirono-
mid midges,were typical in each of the microhabitat types but were most
common in pools.Burrowers in riffle and run habi.tatswere probably
represented by a different assemblege of chironomid species than that in
pool habitats.These reophi10us chironomids would probably fall under a
different behavioral type,such as sprawlers,if a taxonomic level other·
than family were used to categorize invertebrates.Clingers which
inc 1ude such fami 1 i es as Heptageni i dae (Ephemeroptera),Hydropsychi dae
(Trichoptera),and Simuliidae (Oiptera),and swimmers and sprawlers
which include Baetidae (Ephemeroptera:swimmer),Nemouridae (Plecoptera:
spraw1er),and Limnephilidae (Trichoptera:sprawler)occurred in both
riffle and run microhabitats but were more comnon in riffle microhabitat
types.
3.2.1 Benthic Habitat Suitability Criteria
Utilization histograms for the habitat variables of depth,velocity,and
substrate were constructed for the four benthic invertebrate behavioral
types:burrowers,swinmers,clingers,and sprawlers (Figures 10-21).
These utilization curves were then modified using pertinent literature
and professional judgement to derive weighted habitat suitability
criteria (Table 8)for input in the HABTAT habitat simulation model.
The derivation of the wei ghted habitat suitabi lity criteri a for each
habitat variable and each behavioral grouping is presented below.
3.2.1.1 Depth
Based on frequency analysis and professional judgement,the depth
utilization histograms for the four behavioral types (Figure 10-13)did
not appear to show that a cl ear re 1ationshi p exi sted between the den-
sities of benthic organisms present and the ranges of depth utilized.
Because of this,a suitability index value of 0.00 was assigned to a
depth of 0.0 ft.and a suitability index value of 1.00 was assigned to
30
~BURROWER
~SWIMMER
~SPRAWLER
~CLINGER
SC SIDE CHANNEL
SS SIDE SLOUGH
n NUMBER OF
SAMPLES
n=9
280
260
240
220
200
180
160
140
120,
100
80
60
40
20
O...&ollOo'l-"l-~f-&---r-~~"""""""-r----r---e.-¥-oI.o.I.oj~"--oor---L.oI~,"",,",f-'"----,-"""""r"""-'""T-
r
SC 55 SC 55
RIFFLE RUN
JUNE 24 -JULY 10
SC SS SC SS SC 55
POOL RIFFLE RUN
AUGUST 23 -SEPTEMBER 7
i""
i
I,
Figure 9.Average density of benthic fish food organisms (no./yd 2 )by
behavioral type in riffle,run,and pool habitats in side
channels and side sloughs,from June 24 to July 10 and August 23
to September 7,middle Susitna River,Alaska,1984.Behavioral
groups with fewer than five individuals per square yard are not
shown.
31
J ]I I -1 1 _....)J j 1 --1 1 1
BURROWER
1.0
X
lLI
Q
Z
>-
I--..J-0.4 m~-;:)
U)
0.2
0.6
0.0.,",1.8 2.0 10.0
n=II
~
1.61.4
n=32
1.21.0
n=44
n=60
0.2 0.4 0.6 0.8
n=51
Depth Suitability Curve
I 95%Confidence Interval
•Mean
a Suitability Criteria Point.
O 0
J~~i.Jf';.k ~IIJI ~;')lffiil;:~~·IJ..iii iii
0.0
35'°1
0::
lLIm
:E
::l 5.0:z
Z«
lLI
::E
....o
IN
~....
COo.
::::15.0
(J)
0::
lLI
~o
0::
0::::l .mIO.O~
W
N
DEPTH (ft)
Figure 10.Average number of burrower invertebrates per benthic sample for each depth
increment.with hand fitted suitability curve.middle Susitna River.Alaska.
1984.
SWIMMER
1 1 J 1 I J )J ~J I J 1 J
n=1I
n=32
~
n=44oSuitabilityCriteriaPoint
1.2
Depth Suitability Curve
2.41 1 95 %Confidence Interval
/•Mean
-....
1.0
0.6 >-...-...J-m
~-~
en
0.2
0.8 X
IJJo
Z
0.4
n=60n=57
1.0
0.4
0.6
0.2
0.0{9 1 1 I ,• I .,I.·Il.lrl I I·1H'f-f-0.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 10.0
0.8
Q)
o.-........
C/)
0::
W
~
::iE-~en....o
0::
IJJm
::iE
::::>z
z«w
::iE
w
w
DEPTH (tt)
Figure 11.Average number of swimmer invertebrates per benthic sample for each depth
increment.with hand fitted suitability curve.middle Susitna River.Alaska.1984.
)j 1 1 1 l c~-l 1 I 1 i i J .I
CLINGER
Depth4.01 I 95%Confidence Interval3.01 •Mean
o Suitability Criteria Point
Suitability Curve
n=32
J3"
n:44
.......
~2.0
lLJ
(!)
Z-...Jo 1.5
X
lLJo
Z
)-
~-.-I-m
~-::)
en
0.2
0.4
0.6
0.8
n=1I
1.6
","",...,=...,.,.,=,.,.:T",.)----------t,11frt.1 .0
1.4
~II hj;~i;,'fl\lf'~iililt,.f"'-0 0iiiiII,-.
1.8 2.0 10.0
n=57
1.0
0.5
2.5
n=60
'5
0:::
Wen
~
::l
Z
Z«
lLJ
:E
.-
N..
'to-
coo
w
-1:0
DEPTH (ft)
figure 12.Average number of clinger invertebrates per benthic sample for each depth
increment,with hand fitted suitability curve,middle Susitna River,Alaska,
1984.
])J I ~1 .]1 ~I j J J 'I
SPRAWLER
Depth Suitability Curve
1.0
0.8
)(
·woz-
>-
t--...J-0.4 m«I--:::>en
0.6
0.2
n=1I
n=32
.I 95 °/0 Confidence Interval
•Mean
o Suitability Criteria Point
n=60
I
n=57
1.0
6.01
$.,I I ,~0.0;",I I ,.I "'.."",,':.:':.,,"""""..,.'",...'~'r ~0.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 10.0
.-
.....o
a::2.0w
m
~
~
Z
z«w
:E
......4.0J)::~:':
CJ)
0:
IJJ
..J
~
:3.0
Q.
CJ)
(\j...
~
COo
w
U1
DEPTH (ft)
Figure 13.Average number of sprawler invertebrates per benthic sample for each depth
increment,with hand fitted suitability curve,middle Susitna River,Alaska,1984.
i·i I I I .J -i I 1 J I ~«)1 I 1
BURROWER
Velocity SUita~ility Curve
>-..--.J-,m«..-
:J
(/)
1.0
0.2
0.4
0.8
n=12 I )(
w
0
0.6 Z
n=17
I 95 °/0 Confidence Interval
•MeanoSuitability Criteria Point
•Samples with Velocity of
0.0 ft/sec
z 5.0«w
:!:
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 2.4 2.6 2.8 3.0
VELOCITY (ft/8eC)
Figure 14.Average number of burrower invertebrates per benthic sample for each velocity
increment.with hand fitted suitability curve.middle Susitna River.Alaska.
1984.
n=25*
"'-35.0 If~j1
eno.-......
(/)25.0
0::
lLJ
~
~20.0
0:::::>m
b 15,0
0::w
01~10.0
:::>z
W
0\
,"">:<')'I"';:><':""':'''i>1 .4th 0 0• . ..1 I I 1 I~'
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 4.3
VELOCITY (1t/88c)
Average number of swimmer invertebrates per benthic sample for each velocity
increment,with hand fitted suitability curve,middle Susitna River,Alaska,
1984.
0.0 IJ'X I "'.'I':<"""1""":'1 :".1:":1""""'"I"
0.0
Figure 15.
1 1 --.")1 J J 1 I ".1 I ";
SWIMMER
Velocity Suitability Curve
7.21I 95 0
10 Confidence Interval n =12
I(\J •Mean......o Suitability Criteria Pointa>4
0
3.71
•Samples with Velocity of..0.0 ft/sec i",.""""."Q,,'.,.,.\.""""""",:.,.,.,.,'.'",J r-1.0"(J)n=8
0:
W
:i:e 0.8-2.8 )(3=
(J)ILl
w 0..........Z0n=17 0.6
0::>-w 1.8 n=14 I-
eD -T ...J:E 0.4 -:::>m
z «I--z 0.91
---
._l~IiI:::lilii!lll![iil:lll!ililjli!i!ili!!li!i!II:III:lili:!!iii!!!i:!lili:::~!!!ijiilli!!:!li!!I:il:ijli:;I~liilllli!!'I!:!::!!!!!!!i:::1 \LO.2
::>
<t T n=24
U)
W --
~
CLINGER
1 )-1 i 1.j I I J 1 J 1 ]J j I
Velocity Suitability Curve
0.0 ~0.0
0.0 0.2 0.4 0.6 o.e 1.0 1.2 1.4 1.6 i.e 2.0 2.2 2.4 2.6 2.8 3.0 4.0
V ELOCITY (It/sec)
Figure 16.Average number of clinger invertebrates per benthic sample for each velocity
increment,with hand fitted suitabiltiy curve,middle Sus1tna River,Alaska,
1984.
n=128.01 I 95 010 Confidence Interval n=17 I(\J ~...•Mean...
5.ofCD o Suitability Criteria Point
0 .*Samples with Velocity of f;:k:'::,:.:·,::::~···1 I r 1.0-......0.0 ft Isecen
0::
w
(!)4.0 0.8z )(-...J n=8 n=12 W
0 0
w Z
00 ...3.0 0.60
n=14 >-a:::
I
I-w n=24 -m --I
T -~2.0 0.4 m
:::><t
Z n=25*I--
~/":II~8 ~:.~,:••i!lr'l\\\'))I\;I\;:I}l~,'r~',.··:·.'·1'\/.••.•·.•····:···.···.'···:·::···:·>••\i:\/CI \~0.2
:::>z en«1.0 Tw
:i
-..}I J J J J I I I 1 I J )-1 1 J i J
7.0)::
l'
6.0
I ,,"~8N5.0-~
CDq-....
U)
4.0ffi
..J•c
Ifen 3.0
~
0w
Q:
ID
W
CD
:=E 2.0;:)
Z
Z
C
~1.0
"=18
~
,,"26
SPRAWLER
Velocity Suitability Curve
I 95-1_Confidence Interval
•Mean
o Suitability Criteria Point
•Samples with Velocity of
0.0 ft/sec
,,=11
".,
1.0
0.8
""12 ,I )(
W
Q
Z
0.6
)-....
..J
0.4 iii
CI:
I-
;:)
U)
0.2
o.a "', ,I '"I "1"1'1"f ;1<;I ;i I~a.a
0.0 0.2 0,4 0.6 0.8 1.0 1.2 1,4 1.6 1.8 2.0 2.2 2,4 2.6 2.8 3.0 4.0
VELOCITY (ltl'ec)
Figure 17.Average number of sprawler invertebrates per benthic sample
for each velocity increment with hand fitted suitabiltiy
curve.middle Susitna River.Alaska.1984.
1 1 1 .J -I I J J -.1 I -J J E 1
BURROWER
Substrate Suitability Curve
1.0
I 95 010 Confidence Interval
•Mean
o Suitability Criteria Point
I
n=43
0.8
1 X
l&J15.0-1
0
0.6 Z
n=86 I >-~-r--10.0-1 r
n=53 ..J
0.4 -m
<I
t--";r··,I ,4J ::;:)1 ·1 .......I U)5.0-1
0.2
20.0
30.01
N......
CO
.q-......
U)a::
L&J
~
0a::a::
::;:)m.a::.
~0
a::
L&Jm
::IE
::;:)
z
z«
L&J
:E
4 5 6 7 . 8 9 10 II
8m.Grovel Lg.Gravel Rubble Cobble
3
Sand
2I
Silt
I 1-0 .0IiI I I I /2 13O.O..L-j i ,I Bo"Ido,
SUBSTRATE CLASS
Figure 18.Average number of burrower invertebrates per benthic sample for each substrate
increment,with hand fitted suitability curve,middle Susitna River,Alaska,
1984.
)-1 -1 -I J J )J 1 I 1 1 I
SWIMMER
Substrate Suitability Curve
0.6
0.2
0.8
1.0
X
l&Jo
Z-
>-...-...J_.
0.4 m
<l...-:l
(J)
I 95%C'onfidence Interval
•Mean
o Suitability Criteria Point
10 II
Cobble
•'1 I I +0.0
t 2 t 3
Boulder
1"
n=86
9
Rubble
n=22
I
4 5 6 1 8
Sm.Grave.LQ.GrQve~-
3
Sand
2I
Slit
0.0 '@ I.I mi",.'1 I
....o
~0.6
m
:E
::>z
z 0.3
<!
l&J
2
C\I-....
CD
~1.2-.....
(J)
a:
IJJ
2
2 0.9-~
(J)
.r-
~
SUBSTRATE CLASS
Figure 19.Average number of swimmer invertebrates per benthic sample for each substrate
increment.with hand fitted suitability curve,middle Susitna River,Alaska,
1984.
~~J )1 J J J 1 1 I )]
CLINGER
Substrate Suitability Curve
)(
lIJ
C
Z-
>-I--..J
m
<t....-::>rn
1.0
0.8
0.2
0.6
0.4
.n-86
I
··..········"1 r"'",."'(.,"I I'i I 0.0
12 13
Boulder
4 5 6 7 8 9 10 II
Sm.Grave'Lg.Gravel Rubbl.Cobble
3
Sand
2
I 95%Confidence'Interval
..Mean
o Suitability Criteria Point
n-22
I
Silt
.7
1.4
0.0 -L..S;'(i:"""'}::;I J i};
3.7J
......
rn
0::
lIJ
(!)2.rz-..Jo...o
a::
lIJm
~::>z
z«w
2
N
~...
co 2.8q
~
N
SUBSTRATE CLASS
Figure 20.Average number of clinger invertebrates per benthic sample for each substrate
increment.with hand fitted suitability curve.middle Susitna River.Alaska.
1984.
1 I I I 1 I 1 i j
SPRAWLER
Substrate Suitability Curve
)(
LaJo
Z
0.6
0.2
1.0
0.8
)l-
i--.J-0.4 mct...-:l
UJ
I 95 %Confidence Interval
•Mean
o Suitability Criteria Point:I
n;:86
n-22
""'·""'f·"""·""''''''''·'·1 I'I·."".,1 I I-0.0
12 13
Boulder
I
4 5 6 7 8 9 10 II
Sm.Gravel LQ.Gravel Rubble Cobble
3
Sand
2I
Silt
1.50
0.00 l..Jui??ii?>ihl
·0.75
~3.00......
UJ
0:
W
.J
~2.25
0:
CL
(/J
z«w
:I!
....o
0:
W
m
2:
::J
Z
"'::4,
75 1
co ';,'o
~w
SUBSTRATE CLASS
Figure 21.Average number of sprawler invertebrates per benthic sample for each
substrate increment,with hand fitted suitability curve,middle Susitna
River,Alaska.1984.
J 1 1 J !1 1 -.
Table 8.Suitabil ity criteria values for invertebrate behavioral groups for depth,velocity,and substrate type,middle Susitna
River,1984.
Burrower Swimmer Clinger Sprawler
feet suitability feet suitability feet suitability feet suitability
Depth 0.0
0.1
10.0
0.00
1.00
1.00
0.0
0.1
10.0
0.00
1.00
1.00
0.0
0.1
10.0
0.00
1.00
1.00
0.0
0.1
10.0
0.00
1.00
1.00
-4:=0
-4:=0
Burrower Swimmer Clinger Sprawler
ft/sec suitability ft/s8C suitability ft/sec suitability ft/s8C suitability
Velocity 0.0 1.00 0.0 0.02 0.0 0.03 0.0 1.00
0.5 0.19 0.9 0.16 0.9 0.23 3.0 1.0p
2.3 0.19 •1.8 0.54 1.5 0.49 4.0 0.00
3.0 0.00 2.2 1.00 1.8 1.00
3.0 0.54 2.3 0.90
4.3 0.00 3.0 0.10
4.0 0.00
Burrower Swimmer CHnger Sprawler
code suitability code suitability code suitability code suitability
Substrate 1.0 1.00 1.0 0.00 1.0 0.03 1.0 0.24
5.0 0.26 4.0 0.00 3.0 0.03 3.0 0.24
13.0 0.26 6.0 0.83 6.0 0.52 6.0 0.83
9.0 1.00 9.0 1.00 9.0 1.00
12.0 0.25 12.0 0.42 12.0 0.43
13.0 0.42 13.0 0.43
all depths greater than 0.0 ft.In this way,any wetted area could be
considered usable habitat to the four behavioral types.
3.2.1.2 Velocity
The velocity histograms (Figure 14-17)for each of the behavioral types,
with the exception of sprawlers,revealed that a clear relationship
existed between the densities of organisms present and incremental
changes in water velocity.The derivation of the velocity suitability
criteria for each behavioral type is presented below.
The relationship between sprawler densities and water velocity was not
clearly defined by the utilization curve (Figure 17).Early instar
sprawlers were dominant at low velocity (0.0 to 0.6 ft/sec)whereas
middle and late instar sprawlers were dominant at high water velocities
(1.6-2.6 ft/sec).This coupled with the overall total small catch of
sprawlers did not lead to a clear velocity utilization pattern for
sprawlers.However,because sprawlers appeared to be distributed over
the entire range of velocities observed and no pattern in the distri-
bution was apparent,a suitability index of 1.00 was assigned to the
overall range of water velocities from 0.0 to 3.0 ft/sec.In the way,
any moving water could be considered usable habitat.Four feet per
second was used as an endpoint as this velocity was considered that
which becomes uninhabitable by sprawler type organisms (Harris and
Lawrence 1978,Surdick and Gaufin 1978).
The velocity utilization histogram for burrowers (Figure 14)showed
greatest densities at a water velocity of 0.0 ft/sec.As a result,this
velocity was assigned a suitability index of 1.00.This is supported by
findings of other researchers who have shown similar results for benthic
invertebrates belonging to the burrower behavioral type (White et al.
1981,Anderson 1982).A suitability index of 0.19 was assigned to the
range of water velocities from 0.5 ftlsec to 2.3 ft/sec based on the
util ization data.The util ization of these water velocities by inverte-
brates categorized as burrowers is probably due to the presence of
chironomid species which would have been categorized under a different
behavioral type,such as sprawlers,if a taxonomic level lower than
family were used to classify individuals.For this reason,all the
invertebrates utilizing the range of velocities from 0.5 ft./sec.to 2.3
ft./sec.are probably not true burrower types even though categorized as
such.However,such a system of categorization (e.g.,all chironomids
categorized as burrowers)was used because it simplified the analysis of
data yet grouped the majority of individual belonging to a family under
one behavioral type.A suitability of 0.0 was assigned to 3.0 ft/sec as
Anderson {1982}showed that Chironom1dae,a common burrow type organism,
had the lowest mean number of individuals at this velocity.
The assignment of velocity suitability indices for swimmers generally
followed the utilization histogram for this behavioral grouping.
Outside the range of utilization data available,suitability indices
were assigned based on literature.A water velocity of 3.0 ft/sec was
assigned a suitability index of 0.54 based on findings by Judy and Gore
(1979)and Anderson (1982).A suitability index of 0.0 was assigned to
45
i"'
,..,.
a velocity of 4.3 ft/sec as this is considered the limit of water
velocities inhabitable by swimmer type organisms (Judy and Gore 1979).
The observed utilization patterns for clingers in this s~udy (Figure 6)
generally compared well with work done by Newell (1976),Anderson
(1982),Judy and Gore (1979)•.Therefore,corresponding suitability
values were assigned based on the utilization histogram for this behav-
ioral group.Newell's ·(1976)and Andersen 1 s (1982)findings were used
to describe suitability beyond the range of the utilization data.Based
on their findings,a velocity of 3.0 ft/sec was assigned a suitability
index of 0.10 and 4.0 ft/sec was assigned a suitability index of 0.00.
3.2.1.3 Substrate
All benthic invertebrate behavioral groups showed relationships between
densities of benthic organisms and substrate size.Based on the utili-
zation histogram,burrowers had their highest densities in silt to
sand/small gravel substrates (Figure 18).This coupled with findings by
Kennedy (l967)and Bjornn et al.(1977),which support burrower type
benthic invertebrates'utilization of fine substrates,lead to the
assignment ofa suitability index of 1.0 to silt substrates.Because
utilization of small gravel through boulder substrates was fairly
uniform,a sUitability index of 0.26 was assigned to this range of
substrate sizes.The uniform utilization is likely due to the presence
of more than one species of chironomids.
The assignment of substrate suitability indices for swimmers generally
followed the utilization histogram for this behavioral grouping (Figure
19).Because the highest densities of swimmers were on large gravel/-
rubble to rubble/cobble substrates,this substrate class was assigned a
suitability index of 1.00.Assignments of suitability indices for other
substrate classes generally followed the utilization histogram for this
behavioral grouping.These substrate util ization trends compare well
with results obtained by Bjornn et aT.(1977)and Judy and Gore (1979)
for swimmer type benthic invertebrates.
Substrate utilization results for clingers were also similar to results
obtained by Bjornn et al.(1977).As with swimmers,large gravel/rubble
through rubble/cobble substrate had the highest densities of clingers
(Figure 20).Assignments of suitabil ity indices for other substrate
classes generally followed the utilization histogram for this behavioral
grouping.
Sprawler densities were also highest on large gravel/rubble through
rubble/cobble substrate (Figure 21).As a result,this substrate class
was assigned a suitability index of 1.00.Assignment of SUitability
indices on the tails of the sprawler utilization histogram generally
followed the utilization data.These results agree well with findings
by Merritt and Cummins (1975)and Anderson (1982)for sprawler type
benthic invertebrates.
46
....
.....
3.3.2 Benthic Weighted Usable Area Projections
Projections of the gross surface area and WUA of burrower,swimmer,
clinger,and sprawler invertebrate habitat as a function of site flow in
Slough 9,Side Channel 10,Upper Side Channel 11,and Upper Side Channel
21 are shown in Figures 22-25 and Appendix F.For the range of site
flows at each study site that are directly controlled bymainstem
discharge,the gross surface area and WUA projections as a function of
mainstem discharge are also presented.
Typically,projections of gross surface area at each of the study sites
increase over the range of site flows and mainstem discharges modelled.
"rhe most rapid increases in gross surface area generally occur at the
lower site flows prior to each site becoming breached and subsequently
controlled by mainstem discharge.Subsequent to the site flows becoming
controlled by mainstem discharge,the increases in gross surface area
begin to level off.
The projections of WUAof swimmer,clinger,and sprawler habitat at each
study site generally followed similar trends as the projections ofgros's
surface area with the exception that WUA projections peaked or leveled
off at some site flow/mainstem discharge.In contrast,the projections
of burrower WUA typically decreased over the range of site flows/-
mainstem discharges modelled.Typically,the projection of WUA of each
of these behavioral groups were less than 30%of the projected gross
surface area.
The WUA for swilllT1er,clinger,and sprawler habitat in Slough 9 peaked at
a mainstem discharge between 28,000 and 30,000 cfs (Figure 22).The
maximum WUA for sprawler habitat,however,was approximately double the
maximum WUA of either swimmer or clinger habitat.In contrast,WUA of
burrower habitat decreased over the entire range of mainstem discharges
modelled.The initial and controlling breaching discharges for Slough 9
are 16,000 and 19,000 cfs,respectively.
The WUA of swimmer,cl inger,and sprawler habitat did not peak at any of
the mainstem discharges modelled in either Side Channel 10 or Upper Side
Channel 11 (Figures 23 and 24).The WUA for these behavioral groups
increased with increasing mainstem discharge.In contrast,burrower WUA
remained rel atively constant in Side Channel 10 and decl ined in Upper
Side Channel 11.The controlling mainstem breaching discharge at Gold
Creek for Side Channel 10 and Upper Side Channel 11 are 19,000 cfs and
16,000 cfs,respectively.
The amount of WUA of swimmer,cl inger,and sprawler habitat in Upper
.Side Channel 21 peaked at an approximate mainstem discharge of 31,800
cfs.The maximum amount of WUA for sprawler habitat,however,was
approximately triple the amount of WUA of2 either clinger or sprawler
habitat.Burrower WUA peaked at 21,000 ft at an approximate mainstem
discharge of 24,000 cfs.The controlling mainstem breaching discharge
at Upper Side Channel 21 is 24,000 cfs.
47
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X GROSS SURFACE AREA o BURROWER WUA +SWIMMER WUA o CLINGER WUA c:.SPRAWLER WUA
Figure 22.Projections of gross surface area and WUA of burrower.swimmer.clinger.and
sprawler invertebrate habitat as a function of site flow and mainstem discharge
for the Slough 9 modelling site.
I
".
J -1
SIDE CHANNEL 10
INVEftTEB/llATE HABITAT
ae202224
(Thouaanda)
WAI"'STOoi DISCHAft~E (cl.)
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X OROSS SURfACE AREA a BURROWER WUA +SWIMMER WUA o CLINGER WUA 6 SPRAWLER WUA
Figure 23.Projections of gross surface area and WUA of burrower,swimmer,clinger,and
sprawler invertebrate habitat as a function of site flow and mainstem
discharge for the Side Channel 10 modelling site.
:i.,
I I I ·--1 ----i
UPPER SIDE CHANNEL 1 1
INVERn:IIMTE HAIIITAT
120 120
110 1 I - -CONTROLLING IIIAINSTU.110 ~I DISCHARGE
100 100
10 10
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r81'auaandat
SITE FLOW (cre).......NS DISCHAR E (de)
)(GROSS SURFACE AREA a BURROWER WUA +SWIMMER WUA o CL.INGER WUA .c SPRAWL.ER WUA
Figure 24.Projections of gross surface area and WUA of burrower,swimmer,clinger,and
sprawler invertebrate habitat as a function of site flow and mainstem
discharge for the Upper Side Channel 11 modelling site.
--~J
UPPER SIDE CHANNEL 21
INIII:ItTIBAATE twllTAT
34322112830l1'hou.Gnd.l
IiWHstnI DISCHMnE (cr.)
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X GROSS SURFACE AREA o BURROWER WUA +SWI ....ER WUA o CLINGER WUA 6 SPRAWLER WUA
Figure 25.Projections of gross surface area and WUA of burrower,swimmer,clinger,and
sprawler invertebrate habitat as a function of site flow and mainstem
discharge for the Side Channel 21 modelling site.
""I"'
I
I
"'F"
I
I
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'i
!
3.3 Invertebrate Larval Development
The results of·the examination of wing pads from individuals from five
families of Plecoptera and four families of Ephemeroptera are shown in
Table 9.These data reveal that high proportions of Capniidae and
Taeniopterygidae were in late instar larval stages in late April and mid
May.Nemouridae was probably in the adult and egg stages during this
time period.Proportionately high numbers of early and middle instar"
i ndi vi dua 1sof these stonefly families were present during June through
ea rly October.
During late April and middle May,Chloroperlidae and Perlodidae had a
proportionately high number of middle instar individuals present.All
three i nstar groups were present among the Chl oroperli dae from June
through early September.Over half the individuals in Perlodidae were
middle and late instar individuals in June through mid July.In August
and early September,all the individuals in Perlodidae were early
instar.
High proportions of middle instar individuals were present among the
Ephemeroptera in late April and mid May.There were no late instar
individuals identified among the four families of Ephemeroptera for
these two time periods.From June through mid July,high proportions of
middle instar Baetidae and early instar Heptageniidae and Ephemerellidae
were recorded.Through August and early September Ephemeropteran fam-
ilies had individuals whi~h were mostly early instars.
3.4 Juvenile Chinook Salmon Diet
Seventy two juvenile chinook salmon ranging in total length from 38 mm
to 85 mm (1.49 in.-3.35 in.)with a mean total length of 53 mm (2.09
in.)were collected for stomach content analysis.The fish were cap-
tured under both turbid and non-turbid water conditions over all sub-
strate types.Mean water velocities and water depths under these
conditions ranged from approximately 0.0 ft/sec to 1.5 ft/sec and 0.2 ft
to 2.0 feet,respectively.The majority of fish were captured at the
head of pools or runs adjacent to faster water velocities •.
The juvenile chinook salmon stomachs examined contained twelve orders of
invertebrates consisting of eleven insect orders and one non-insect
order (Appendix Table E-1).The eleven insect orders were identified to
fifteen families.The majority of juvenile chinook salmon stomachs
examined contained food items.Only two of the stomachs examined were
empty.Figure 26 shows the percent contribution of the total numbers of
seven different invertebrate taxonomical groups.Figure 27 shows the
percent contribution of sixteen benthic invertebrate famil ies grouped
into the four behavioral types used in WUA calculations.Figures 26 and
27 also show the percent contributions for invertebrates in benthos and
drift samples.
3.5 Turbidity at Study Sites and Mainstem Susitna River
Water samples were collected for measurement of turbidity at Slough 9,
Side Channel 10,Upper Side Channel 11,and upper Side Channel 21 from
52
~,
Table 9.Percentage of early.middle.and late instar larval aquatic insects and the total
number of individuals examined ().middle Susitna River,Alask~,1984.Indi vi dua 15
examined from April.May,September.and October samples are from synoptic surveys.
Family/Date June 7 -August 9 -
April 25-26 May 15 July 14 September 9 October 10-11
Nemouridae (1)(0)(22)(27)(0)
Early 100 95 74
Middle 26
Late 5
"""Capniidae (41)(3)(5)(237)(31)
Early 60 99 58
Middle 5 1 42
Late 95 100 40
Taeniopterygidae (14~)(5)(2)(111)(831)
Early 100 100 99
Middle 81 20 1
f':""Late 19 80
Chloroper1idae (9)(1 )(71 )(35)(0)
.-Early 11 41 74
I Middle 78 100 49 9
Late 11 10 17
Perlodfdae (30)(0)(74)(24)(3)
Early 30 49 100 33
Middle 70 46 67
Late 5
r:-
Baetidae (123)(1 )(399)(19)(4)
Early 13 21 63 100
Middle 87 100 71 32
Late 8 5
Heptageniidae (10)(0)(168 )(63)(8)
Early 74 51 50
Middle 100 16 40 38
Late 10 9 12
Ephemerellidae (22)to)(89)(31 )(1 )
Early 96 84 100
Middle 100 4 16
.....Late
Sfphlonuridae (2)(226)(17 )(3 )(0)
Early 13 41 100
Middle 100 87 59
Late ~-
-
53
10%
Invertebrates 27%
Ephemeroptera 7%
Collembola 0%
Benthic Invertebrate S~niples
Trichoptera 4%
Larval Diptera 52%
Other Insects 0%
Invertebrate Drift Samples-
-
Larval Diptera 24%
Other Invertebrates 6%
Trichoptera 3%
.Plecoptera 4%
Ephemeroptera 7%
Collembola 3%
Other Insects 8%
Adult Diptera 45%
Ephemeroptera 4%
Collembolo 1%
Other Insects 5%
Adult Diptera 29%
Juvenile Chinook Stomach Contents
Trichoptero 1%
Plecoptera 14%
Larval Diptera 46%
Other Invertebrates 0%
-Figure 26.Percent composition of invertebrates in benthic,drift,.
and juvenil e chinook stomach content sampl es taken at
FAS sites,middle Susitna River,Alaska,1984.
C:J1
I......
I
Benthic Invertebrote Samples
Burrowers 69
Swimmers 5%
Clingers 12%
Sprawlers 14%
Invertebrate Drift Samples
Burrowers 52%
--
Swimmers 29%
Clingers 16%
Sprawlers 3%
Juvenile Chinook Stomach Contents
.....
I
Burrowers 87%
Clingers 6%
Sprawlers 1%
Swimmers 6%
Figure 27.Percent composition of aquatic insect behavioral groups
in benthic drift,and juvenile chinook stomach content
samples taken at FAS sites,middle Susitna River,
Alaska,1984.
"""',
June 7 to September 9,1984.Turbidity measurements of water from the
main channel of the Susitna River were taken monthly at Gold Creek by
the U.S.Geological Survey,Water Resources Section from May 31 to
September 28,1984.Appendix F-1 shows the turbidity values obtained
for each of these locations during the invertebrate sampling period.
Turbidity values ranged from one to 344 NTU (Nephelometric Turbidity
Units)at IFG-4 sites and from 28 NTU to 320 NTU at head sites.Side
channel and side slough head sites generally had higher turbidity values
than IFG-4 sites.The IFG-4 sampling site in Lipper Side Channel 11 had
the highest turbidity values.Turbidity values at the IFG-4 transect
site in Upper Side Channel 21 were relatively low by comparison.
The breached or unbreached condition of Slough 9,Side Channel 10,Upper
Side Channel 11,and Upper Side Channel 21 at the time of water samples
were collected for turbidity measurement is also shown in Appendix F-l.
Slough 9 and Upper Side Channel 11 were almost always breached during
water sampling.Side Channel 10 and Upper Side Channel 21 were fre-
quently unbreached.
56
-
~
I
-
-
4.0 DISCUSSION
4.1 Available Food Sources for Juvenile Chinook Salmon in
Side Channels and Side Sloughs
The scatter plots of log transformed invertebrate drift data (Figures '7
and 8)indicate that,under breached conditions in side channels and
side sloughs,drjfting invertebrates'(e.g.,invertebrates drifting in
response to changes in light conditions)at IFG-4 sites were similar to
those at head sites and that the density of drifting invertebrates at
IFG-4 sites was only sl ightly less than that at head sites.The data
also reveal that at or near breaching discharges,fewer drifting orga-
nisms were observed at the IFG-4 sites than at head sites,whereas
during unbreached conditions,IFG-4 sites had more than the few or no
drifting invertebrates expected (Table 10).Based on this,it is
concluded that the invertebrate drift measured at IFG-4 sites located in
middl~Susitna River side channels and side sloughs is usually governed
by the breaching flows of the mainstem.These flows presumably trans-
port drifting invertebrates from the mainstem into the side channels and
side sloughs where they become available as potential food for juvenile
salmonids.Whether these invertebrates originate in the mainstem could
not be determined by this study.
In terms of availability,these drifting invertebrates may be of greater
importance to the feeding juvenile salmonids when their rate of drift
(i.e.,the number of drifting invertebrates passing a point per u~it of
time)is increased.This generally occurred when sample sites were
breached or at breaching and was generally the resul t of increased water
velocity from either large volumes of water inundating sample sites or
from small volumes flowing rapidly over the the various study site
substrates.This increased drift rate,which results during mainstem
flows that just breach side channels or side sloughs.,may be more
beneficial to feeding fish than the drift which occurs at other times,
since water in the study sites under these conditions is less turbid
enabling fish to more easily see their prey.
The standardized drift data al so showed that Ephemeroptera,especially
of the family Baetidae,and Plecoptera were numerically important drift
components during mid June and mid August,respectively.Chironomid
midges were the most consistently numerous family of invertebrates
present in the drift from June through August.There is some evidence
that this pattern in the drift,especially for Ephemeroptera,is related
to the presence of proportionately large numbers of near emerging
adults.Perry and Huston (1983)found that the drift rates of inverte-
brates below Libby Dam in the Kootenai River,Montana were higher during
months when common species were near emergence.Hynes (1970),after
reviewing the literature,stated that distinct downstream movement of
some species of Simuliidae,Ephemeroptera,and Plecoptera shortly before
emergence as adults was a widespread phenomenon.Examination of wing
pad deve 1opment among famil i es of Ephemeroptera in th is study showed
that this group had proportionately more middle and late instar indi-
viduals present during June and early July than during August.
Ephemeropterans reached their highest densities in the drift and benthos
within this same period.
57
1 j -~I 1 1 -1 I •.._~I 1 1
Table 10.Standardi2ed densities (no/l000 feet S )of drifting invertebrates (Invert)a and adult aquatic insects (Adult)b at head and IfC-4 sites,middle Susitna River,1984.
Upper Side Channel 11 Side Channel 21 Slough 9 Side Channel 10
HEAD .I FC-4 HEAD IfC-4 HEAD IfC-4 HEAD IfC-4
(late lnvert a--·-A-dultb Inverta Adult b Invert a Adult b Invert a Adultb Inverta Adultb Inverta Adult b Inverta Adult b Inverta Adult b
June 7-8 143 23 47 22
June 9-10c ---.185 315 1 3
June 11-12 -.---- --32 23 13 8
June 13-14 d ---- -
-------153 20 110 18
Jul y 7-8 42 26 30 44
July 9-JOc .---16 39 6 3
July 11-12 .----- --41 9 52 23
(Jl July 13-14 C -- -
--------.22 6 7 4
OJ
August 9-10 65 83 43 46
August 11-12 ---.-e -e 53 204
August 13-14 ----.---53 60 65 31
August 15-16 -,---.-.-.--- -
e -e 13 26
-
a includes non insect adults and larva,terrestrial insects,and aquatic insect larvaebIncludesadultaquaticinsectsonlyc
d at breaching point
lampl ed one day at head si teenOsample,unbreached condition
.....
-
,.-
r
i
I
i'"
i
I
,
F"'"
I
The relatively high densities of Plecoptera in the drift in early-August
may be a result of the higher numbers of early instar individuals in the
benthos.Early instar Plecoptera were cOl1l11on in the drift during this
time.Waters (1972)"in reviewing the literature,found that some
species of insects have been observed to have their greatest drift rate
during 'early life cycle stages.
Besides behavioral drift from the mainstem,there is another possible
kind of drift that could occur in side channels and side sloughs which
would make invertebrates available as food.This drift is termed
catastrophic drift (Waters 1972).Catastrophic drift can occur under
two circumstances:1)when there is physical disturbance of the bottom
fauna,usually by a flood event (Anderson and Lehmkuhl 1968,Scullion
and Sinton 1983);or 2)under conditions of receding water as a result
of reductions in flow (Minshall and Winger 1968,White et a1.1981).
Though both circumstances could initiate catastrophic drift in any of
the four study sites,there is the possibility that conditions are ideal
for drift of this nature to occur as a result of the first circumstance
in Upper Side Channel 21.In Slough 9,Side Channel 10,and Upper Side
Channel 11 catastrophic drift could possibly occur as a result of the
second circumstance.An increase in the amount of potential fish food
organisms made available through catastrophic drift of the first circum-
stance,however,is probably not of significance in the four study sites
under current conditions.However,any catastrophic drift which does
occur within the four study sites is probably masked by the volume of
behaviorally drifting invertebrates immigrating from the mainstem.In
Slough 9,Side Channel 10,and Upper Side Channel 11 it is likely that
catastrophic drift occurs but probably is limited to a few occurrences
during the entire open water season and then possibly only in August or
September during receding flows.
4.2 Effects of Flow on the Distribution and Abundance of Benthic
Invertebrates in Side Channels and Side Sloughs
Categorizing important fish food organisms into behavioral groups proved
to be a valuable tool in projecting the habitat preferences and weighted
usable habitat area when the mean density of these organisms was less
than 500 individuals per square yard.By grouping organisms on a
behavioral basi s,it was possibl e to eval uate group preferences for
specific velocities and substrate types which otherwise would be unde-
tectable if organisms were treated on a taxonomic basis.
4.2.1 Habitat Suitability
Four behavioral groups of benthic invertebrates were identified which
reflected basic habitat preferences:burrower,swimmer,cl inger,and
sprawler.In general,burrowers were reflective of slower deeper
waters,such as pool s,and swimmers,cl ingers,and sprawlers were
reflective of faster shallower waters,such as riffles and runs.
Pool-like habitats are typical of the backwater zones at the mouths of
side channels and side sloughs whereas,riffle and run habitats are more
typical of the head and middle portions.
59
-
"""'
r-
I
-,
The relationship between behavioral type and habitat type are likely the
result of morphological and physiological adaptations'of benthic orga-
nisms to their environment.For example,swimmers and clingers (which
include baetid and heptageniid mayflies),are fusiform and dorso-
ventrally flattened respectively and usually have higher oxygen require-
ments than other insects (e.g.Chironomidae)and therefore would more
likely be found in faster flowing water (Hynes 1970).Burrowers on the
other hand are cylindrical in shape and are adapted for digging in fine
mineral or organic sub~trates (e.g.silt and sand).This group would
more likely be found in slower moving waters such as pools.
The numerical productivity andconununity structure of invertebrates in
riffle,run,and .pool habitats of side channels and side sloughs of the
middle Susitna River in presented in Table 11.In general,riffle and
run habitats had a more diverse and evenly distributed assemblages of
taxa than pool s.Numerically,pool habitats appeared to be the more
productive habitat during late summer.Production based on this
measure,however,is not conclusive and riffles and runs are probably
more important on a biomass scale.Hynes (1970)states that in general
riffles are more productive than pools,in part because of the diverse
number of microhabitats which could be occupied by organisms of various
sizes.The partial diversity (i .e.,the diversity based on gross
taxonomic identifications),evenness,and mean number of taxa calculated
for riffles appears to substantiate Hynes'conclusion.The diversity,
eveness,and number of taxa in riffles and runs were consistently higher
than in pools,probably because of the limited number of microniches
available to invertebrates in this habitat type.
4.2.2 Weighted Usable Area
Projections of weighted usable area (WUA)for the four behavioral groups
are a measure of the amount of riffle-like and pool-like habitat made
available to colonizing organisms at various site flows and mainstem
discharges.At all four study locations,burrower WUA generally
decreased with increasing site flows and mainstem discharge.Upper Side
Channel 11 and Upper Side Channel 21 were the only two locations which
had an increase in the amount of burrower WUA between initial and
controlling discharges.These changes in WUA are probably the result of
changes in the area of backwater zone at each study site.Apparently,
the hydraulic conditions of these zones begin to simulate those of a
deep run at mainstem discharges above those which initiate controlling
flow through side channels and side sloughs.
The amount of WUA for swimmer,clinger,and sprawler behavioral groups
peaked at a mainstem discharge between 28,000 cfs and 31,200 cfs in
Slough 9 and Upper Side Channel 21.The high amount of sprawler habitat
at these two sites and at Side Channel 10 and Upper Side Channel 11 is
probably a reflection of this behavioral groups use of a wide range of
velocities and substrates during the course of its life history.
Sprawlers were comprised primarily of stoneflies from the families
Capniidae and Nemouridae.
The habitats used by swimmer and cl inger behavioral groups were less
varied than those utilized by sprawlers which used a wide range of
velocities.The suitability indices for swirmners and clingers showed a
60
J ]I J 1 'I
Table 11.Diversity ±S.E.,evenness (Poole 1974),density,and number of taxa of benthic invertebrate communities from riffle,run,
and pool habitats in side channels and side sloughs of the middle Susitna River,Alaska,1984.Density and number of taxa
are reported as the average number per square yard %98\confidence interval.
0'\......
Side SloughS b
Rff~lec
Run
poole
5i de Channe 15 f
Rff~lec
Run
poole
Side Sloughs b
Rff~lec
Run
poole
Si de Channe ll,t
Rif~lec
Run
poole
Diversity (H's S.E.)
2.43 :l:0.06
2.60 :l:0.09
2.91 ±0.09
2.64 :l:0.13
1.90 ±0.10
1.64 ±0.06
0.72%0.15
2.55 %0.09
1.70 :l:0.09
0.69 :l:0.11
Evenness (J')
0.59
0.64
0.72
0.72
0.48
0.39
0.25
0.62
0.40
0.22
Density (no./yd2 )
Ear1y-Hid Sumrner a
434.3 :l:393.1
151.2 %90.7
95.8 :l:44.5
46.2 ~24.4
late Summer g
317.5 :l:331.0
163.0:l:76.4
195.7 :l:383.0
165.5:1:79.8
153.7 ±87.4
286.4 :I:270.5
No.Taxa
5.9 ±2.5
4.1 ±1.8
4.0 ±1.3
2.7 ±0.8
4.0 :l:2.4
2.7 :l:0.5
2.7 :l:"3.3
4.6 ±1.4
3.0 :I:1.0
3.0 :I:2.1
No.Samples
15
23
24
26
9
44
6
19
31
7
a Samples taken 6/24/84 through 7/10/84.
b Samples taken at Slough 9 and Side Channel 21 transects.
c Samples taken at transects having an average depth~0.33 feet and an average current velocity~0.33 feet per second.
d Samples taken at transects having an average depth between 0.34 feet"and 0.99 feet and an average currente(0.33 feet per second.
e Samples taken at transects having an average depth »'.00 feet and an average current velocity<:0.33 feet per second.
f Samples taken at Side Channel 10 and Upper Side Channel 11 transects.
9 Samples taken 8/23/84 through 9/7/84.
r-
!
marked preference for velocities between 1.8 ft/sec and 2.2 ft/sec and
substrates comprised primarily of rubble.This preference resulted in a
distinct increase in WUA for mainstem discharges up to 28,000 cfs and
31,200 cfs at Slough 9 and Upper Side Channel 21,respectively,at which
point WUA began to decline.
Projections of WUA for swinuners and cl ingers di d not show a peak for
Side Channel 10 and Upper Side Channel 11. This was probably the result
of the limitations of the hydraulic model for these two study locations
which do not permit predictions of WUA at mainstem discharges beyond
25,300 cfs and side channel flows beyond 100 cfs in Side Channel 10 and
250 cfs in Upper Side Channel 11.The mainstem discharge at which WUA
for swimmers and clingers reaches a maximum in these two side channels
is not known.However,the greatest amount of WUA projected was at a
mainstem discharge between 25,200 cfs and 25,500 cfs.
4.3 Utilization of Available Foods by Juvenile Chinook Salmon in Side
Channels and Side Sloughs
The 1984 FAS and previous Susitna River studies (ADF&G 1978,ADF&G
1983a)have shown that juvenile chinook salmon rearing in the sloughs
.and side channels of the middle Susitna River feed on a wide variety of
aquatic and terrestrial invertebrates (Appendix Table Bl).Of the
invertebrates utilized,chironomid adults and larvae (burrowers)were
numerically dominant in all previous Susitna River diet studies of
juvenile chinook salmon.Loftus and Lenon (1977)determined that
chironomidae were the most important family of food organisms for
chinook salmon smo1ts in the Salcha River,Alaska.Similar results have
been obtained by other researchers (Becker 1973,Daubl e et a1.1980,
Burger et al.1982).
Although th~family Chironomidae was found in this study to be the most
numerically dominant taxa in the diet of Susitna River juvenile chinook
salmon,numerical abundance alone does not necessarily correspond
directly to relative importance (Lag1er 1956).The majority of
chironomids fed on by juvenile chinook salmon in this study were rela-
tively small (1-5 mm in length)and would probably displace a volume of
water measuring at least one order of magnitude less than that displaced
by mi ddl e i nsta r ephemeropterans and p1ecopterans (swimmers,c1i ngers,
and sprawlers).Based on this,it is felt that other aquatic insect
taxa,primarily plecopterans and ephemeropterans,are more numerous in
the diet of juvenile chinook salmon than numerical abundance indicates.
Plecopterans and ephemeropterans were the most numerous invertebrates in
the diet of juvenile chinook salmon next to chironomids in this and the
previous ADF&G (1983)Susitna River diet studies and in Loftus and
Lenon's (1977)Salcha River Study.
Everest and Chapman (1972),Becker (1973),and Loftus and Lenon (1977)
have determined juvenile chinook salmon feed primarily on aquatic
invertebrate drift and floating adult insects.Their findings corre-
spond well with the results of this study which show a closer rela-
tionship between drift catch (includes floating insects)and juvenile
chinook stomach contents than between stomach contents and benthic catch
(Figure 26,Appendix Table A-I).For example,invertebrates from the
62
-
,....
F'"
I
adult Diptera category (primarily chironomids)and Other Insects
category (primarily homopterans)made up 29%and 5%respectively of the
juvenile chinook salmon diet and were available only as drift.In
contrast,organi sms occurri ng in the benthos but not selected as food
included the Oligochaeta.Though this group comprised 27%of the Other
Invertebrates category which in turn made up 27%of the benthic catch,
none of these organisms were found in juvenile chinook salmon diet.
This compares with the previous ADF&G (1983)diet study which reported
few 01 igochaetes in the stomachs of juvenile chinook salmon.Finally,
benthic invertebrates that were not readily found in the drift,did"not
appear to a significant extent in the juvenile chinook salmon diet.The
major invertebrate groups (e.g.,Chi ronomidae,Ephemeroptera,and
P1ecoptera)which have been reported as being good drifters (Hynes
1970)which were present in samples in this study were,however,
consumed by juvenile chinook salmon.
The availability of different aquatic insect groups during the growing
season of juvenile chinook salmon may be an important factor in the
rearing capacity of Susitna River slough and side channel habitats.As
discussed in Section 4.1,middle and late instar ephemeropterans
(swimmers "and clingers)and p1ecopterans (clingers and sprawlers)are
available in significant numbers as drift in June.Large numbers of
early instar plecopterans show up in the drift in August.Adult and
larval chironomids are available as drift from June through August,with
the proportion of adult chironomids increasing as the summer progressed.
Juvenile chinook salmon food utilization generally followed these
trends.Middle and 1ate i nsta r pl ecopterans and ephemeropterans were
consumed primarily in June,early instar plecopterans were important in
August,and chironomid adults and larvae were consumed during the entire
open water season.Larvae from Chironimidae were consumed in early
summer while higher proportions of adults were consumed during the
latter part of summer (Figure 28).
4.4 Conclusions and Future Research
Four major conclusions can be drawn from the results of this study.
First,the diet composition of juvenile chinook salmon is closely
correlated with invertebrate drift composition and,to a lesser extent,
to benthos composition,with midges from the family Chironomidae
(Diptera)being the chief food organism of juvenile chinook salmon.
Secondly,invertebrate drift under breached conditions in study side
channels and side sloughs of the middle Susitna River appeared to be
governed by mainstem flows which transport drifting invertebrates into
the side channels and side sloughs.Under breached conditions,the
drift occurring in the study side channels and side sloughs could be
considered negligible when compared to the drift occurring under
unbreached conditions when total drift is considered.The drift in both
cases was dominated by midges from the family Chironomidae (Diptera),
mayflies (Ephemeroptera)from the family Baetidae,and stoneflies
(Pl ecoptera).
Thirdly,it was determined that categorizing invertebrate taxa by
behavioral type (i.e.by burrower,swimmers,clingers and sprawlers)was
63
I 1 ]J 1 J .---])--,-J
*n=6
SEPAUG
n =18
*Side Channel 21 Fish Only
~EPHEMEROPTER A
~PLECOPTERA
~LARVAL DIPTERA
II ADULT DIPTERA
IIID OTHER INSECTS
n=23
JUL
n=20
20
o '>y<t=
80
JUN
60
LLo 40.-zw
U
0::
Wa..
-.J
<t.-o.-
0\
,J;:o
1984 JUVENILE CHINOOK SALMON DIET
Figure 28.Percent of total numbers of aquatic and terrestrial insect groups 1n juvenile chinook
salmon stomachs from FAS sites,June through September 1984,middle Susitna River,
Alaska.
r
....
a valuable means for projecting benthic invertebrate WUA when the
density of a majority of species averages less than ten individuals per
1.08 ft 2 •It was found that water depth did not appear to be an impor-
tant factor governing the overall .distribution of any of the behavior~l
groups,but that water vel oci ty and substrate type appeared to affect
the distribution of most behavioral groups.Water velocities less than
0.4 ft/sec and substrate types comprised mostly of silt and sand (less
than one eighth inch diameter)correlated well 'with high numbers of
burrowers whereas rubble (three inches to five inches in diameter)
substrates with components of large gravel (one inch to three inches
diameter)or cobble (five inches to ten inches diameter)correlated with
high numbers of swimmers,clingers,and sprawlers.Water velocities
between 1.6 ft/sec and 2.6ft/sec correlated well with high numbers of
swimmers and clingers.Sprawlers did not appear to utilize any par-
ticular velocity over another.
Lastly,it can be concluded that WUA at each of the study sites for each
of the behavioral groups clearly was a function of site flows and
mainstem discharge.The minimum controlling mainstem discharge for a
side channel or side slough generally produced the highest WUA for
burrowers.A controlling mainstem discharge of 25,000 cfs generally
produced the maximum WUA for swinmers,clingers,and sprawlers in Side
Channel 10 and Upper Si de Channel 11.The maximum WUA for swimmers,
clingers,and sprawlers in Slough 9 and Upper Side Channel 21 was
produced at a controlling mainstem discharge of 29,000 cfs and 31,000
cfs,respectively.
In light of the above conclusions,naturally fluctuating.flows of the
mainstem Susitna River appear to increase total drift in side channels
and side sloughs and subsequently the drift food supply for juvenil e
chinook salmon living in these turbid water mainstem affected habitats.
Such periodic fluctuations .also maintain drift for the continuous
recolonization of mainstem affected habitats by invertebrates..
From the above discussion,the natural question arises:how are the
invertebrates which are transported into side channel and side sloughs,
influenced bymainstem discharge fluctuations when domiciled in the
mainstem Susitna River itself?Answers to this and other questions can
only come with further study of the density responses of invertebrates
domiciled along mainstem shorelines to varying frequencies of watering
and dewatering as a result of naturally fluctuating discharges.
65
-I
,
~
I
5.0 CONTRIBUTORS
Project Leader
Aquatic Habitat and instream Flow
Project Leader
Principal Investigators
Editors
Statistical and Data Analysis
Graphics
Typing
66
Douglas Vincent-Lang
Tim F.Hansen
J.Craig Richards
Douglas Vincent-Lang
Joseph Sautner
Allen Bingham
Paul Suchanek
Andrew Hoffman
Tim Quane
Tommy Wi throw
Teri Keklak
Alice Freeman
Katrin Zosel
Carol Hepler
Roxann Peterson
Skeers Word Processing
Anneliese Kohut
Bobbie Sue Greene
-
6.0 ACKNOWLEDGEMENTS
Financial support for this study was provided by the Alaska Power
Author:ity.Harza-Ebasco Susitna Joint Venture supported and hel ped
draft the final study proposal.The authors al so wish to express their
gratitude to Dana Schmidt and Christopher Estes for their insight in
initially proposing this study and to Sandy Sonnichsen for her help in
reviewing the initial proposal.
Diane Hilliard provided the technical expertise in recalibration and use
of the IFG-4 hydraulic models employed in this study.We also
appreciate the cooperation of E.Woody Trihey and Associates during the
data collection,data analysis,and review of the report drafts.
67
....
I
....
7.0 LITERATURE CITED
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Department of Fish and Game Susitna Hydro Aquatic Studies.
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•1983b.Susitna Hydro aquati c studies phase II basi c data
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-
Baumann,R.W.,A.R.Gaufi n,and R.F.Surdi ck.
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American Entomological
208p.
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Becker,C.D.1973.Food and growth parameters of juvenile chinook
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Fish.Bull.71~):387-40 .
68
1981.An introduction
College Publishing,t-
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identifying influential data and sources of coll inearity.John
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Bovee,K.D.and R.Mi1hous.1978.Hydraulic simulation in instream
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Field Station..Anchorage,Alaska.181pp.
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Daub1e,D.O.,R.H.Gray,and F.S.Page.1980.Importance of insects
and zooplankton in the diet of O-age chinook salmon Oncorh~nchus
tshawytscha in the central Columbia River.Northwest SClence.
54(4):253-258.
Draper,N.R.and H.SMith.1981.Applied regression analysis.Second
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.North and Central American.University of Minnesota Press,
Minneapolis.330p.
Everest,F.H.and D.W.Chapman.1972.Habitat selection and spatial
interaction by juvenile chinook salmon and steel head trout in two'
Idaho streams.J.Fish.Res.Bd.Canada 29:91-100.
Giger,R.D.1973.Streamflow requirements for salmonids.Oregon
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Gore,J.A.1978.A technique for predicting instream flow requirements
of benthic macroinvertebrates.Freshwater Biology 8:141-151.
69
1981.User's guide to the
Instream Flow Information
USFWS Instream Flow Service
.-
II"""
I
.....
-
-
-
Harris,T.L.and T.M.Lawrence.1978.Environmental requirements and
pollution tolerance of Trichoptera.U.S.Environmental Protection
Agency,Cincinnati,Ohio.EPA-600/4-78-063.310p.
Hoaglin,D.C.,F.Mosteller,and J.W.Tulkey.1983.Understanding
robust and exploratory data analysis..John Wiley and Sons,New
York..
Hubbard,M.D.and W.L.Peters.1978.Environmental requirements and
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Hynes,H.B.1970.The Ecology of Running Waters.University of
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Johansen,O.A.and L.C.Thomsen.1934.Aquatic Oiptera.Entomological
Reprint Specialists,Los Angeles.425p •
Judy,R.D.and J.A.Gore.1979.A predictive model of benthic inverte-
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Kennedy,H.D.1967.Seasonal abundance of aquatic invertebrates and
their utilization by hatchery-reared rainbow trout.Technical
Paper 12.U.S.Bureau of Sports Fisheries and Wildlife,
Washington,D.C.41 p.
Kimble,L.A.and T.A.Wesche.1975.Relationships between selected
physical parameters and benthic cOl11llunity structure in a small
mountain stream.Water Resources Series No.55,University of
Wyoming,Laramie.64pp.
Lagler,K.F.1956.Freshwater Fishery Biology,2nd ed.Wm.C.Brown
Co.Publishers,Dubuque.421pp.
Loftus,W.F.and H.L.Lenon.1977.Food habi ts of the salmon smo 1ts ,
Oncorhynchus tshawytscha and O.keta,from the Salcha River,
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Merritt,R.W.and K.W.Cummins (editors)1978.An introduction to the
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Associates.Anchorage,Alaska.
70
_.
I
--
,J!!lIl!l$I
Newell,R.L.1976.Yellowstone River Study -Final Report.Montana
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,1.Queral,T.Keklak,and D.Seagren.1984b.Channel geometry
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72
r-
8.0 APPENDICES
Page
.....Appendix A Study Site Hydrographs,Rating Curves
and Discharge Data A-1
I"""Appendix B Benthic and Drift Invertebrate Data 8-1
Appendix C Results of the Multiple Regression,...,Analysis for drift data C-l
Appendix 0 Formulae for Calculating the Shannon-
Weaver Diversity Index and Eveness Index 0-1
Appendix E Juvenile Chinook Feeding Data E-l
f"""Appendix F Weighted Usable Area Projection
Data F-l
Appendix G Water Turbidity G-l
-
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-
-
....
73
-
r
-'.....,
APPENDIX A
Study Site Hydrographs,Rating Curves
and Discharge Data
A-I
I~
J~
APPENDIX A
Appendix A contains a hydrograph for each of the FAS sampling sites and
the mainstem Susitna River at Gold Creek for the 1984 open water season
(Appendix Figures A-I and A-2).Also included are the rating curves
(Appendix Figures A-3 through A-6)and the discharge data (Appendix
Table A-I)used to generate the hydrographs.A narrative of the step-
wise procedure used to develop the hydrographs is also presented.
Hydrograph Development
Discharge was measured twice at Slough 9 and once each at Side Channel
la,Upper Side Channel 11,and upper Side Channel 21 according to
procedures outl ined in ADF&G (l984).These di scharges were taken at
study sites to combine with 1982 and 1983 ADF&G discharge data for
developing rating curves for describing the relationship between
mainstem discharge and side channel or side slough flow.
Rating curves were developed for defining the relationship between
mainstem discharge and side channel or side slough flow at all four
study sites according to procedures described in ADF&G (1984).These
rati ng curves were used to construct hydrographs for side channel or
side slough flows for the period of June 1 through September 30,1984.
Flows above the reconmended predictive range of a site respective rating
curve were estimated using the rating curve equation.The highest flow
measured below controlling breaching mainstem discharge was used to
state the upper limit of base flow in a side channel or side slough.
These flows are published in Quane et al.(1984)and R&M Consultants
(1984).
A-2
1 1 1 1 J 1 )
IdID
___..UN 041LY 0ISCII411G£
lusGs UGI IUUOOOI
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IRE4CIIlIIG 01$CH4RGI
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.FIIO ..UTlIIl;CUIIVI
--- -UTlII4no $1 TI:01$I;H411G£
AlOVI 'II£lIICTlVI 114I1G[
OF 114l1NG CUIIVI
•••••IITI lUI FLOW 1<1,101
1
II
II
II
II
II
II
"I'
SIDE CHANNEL 10
~;WD
I
t~!
lIIIIIO
J ....../U ~C'D I \t illllU ~
7'-,,.'"\.a
IIIllIl
•
-
i4 21 21
SEP
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IUSGS GUI 152120001
--..4INnl..CONTIIOLLING
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IIt,OOO .1,1
_UTUIAnD SIU·01$CH4RGI
FlIo.."'TlNG CUllyl
----UTI..UU lin OIICII,IIGI
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I
(.oj
Appendix Figure A-I.Hydrograph (discharge time)for June •September 1984 for the Susitna River at Gold
Creek (RM 136.5).Slough 9 (RM 128.3).and Side Channel 10 (RM 133.8).
-).J J 1 1 "J J i J
I
*-1 II I •
I !II ,II
~""Ju\,ut--~~..,'IIY"..,...JI'\J.,......,.....I.....:~••,(...,....,....,....\'..
I I ..'tc;-"'-~r I I")20 21 S 10 "24 ,.,14 21 II
JUN JUL AUG SEP
unit
~'.!1:1.'I}
In
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'j
OJ".·1.....,";..t:...
-41011'\
1I
II
19
_IIIUN OAILY DISCHARGE
. 1USGS GAGE Illnooo,
--.IIAINSlllI CONTROLLING
IIlE ACHING DISCHARGE
1'14,000 .hl
_UTlIIATED SITE DISCHARGE
fAOII RATING CURVE
----ESTIIIATED SITE DISCHARGE
ABOVE PREDICTIVE RANGE
OF RATING CUIlVE
•••••SITE IAIt:FLOW 1<'0 d.,
SIDE CHANNEL 21
'N :Qro
1*
0
I:!IlICllI
iii
.111m
.1U11 ~
M··_"i
~'
tl
'ilIDlI ~
:'1
1.'1
,
"''''n;
--...IIUN DAILY DIICHAROI
IUSU GAGE Iinloool
--IIAINUEII CONTROLLIIlG
IRUCHING OIICHAIlQl
lUl,OOO .hl
UPPER SIDE CHANNEL II
~UI1I
1100
o
,
I
1
I :-ESTIIIATEO lITE DISCHARGE
: I FROII RATING CURVE
I :---.ElTIIIATED liTE OIlCHARGE
I 1 AIDVl PREDICTIVE RANliE
I I t Of.RATING CURVE
I I
,~"•••••IITl BAit:FLOW 1 <10 .11 I
.J:!'-1 I I ,I~'1 I'A-.'J\-'j-'--'l~",\n..,.'·'1'"'I"·"·..,....,.
I •'I 22 2t •IS 10 If:S 10 "24 Sl ,14 II II
JUN JUL AUG SEP
)::a.
•~
Appendix Figure A-2.Hydrograph (discharge versus time)for June -September 1984 for the Susitna River
at Gold Creek (RM 136.5),Upper Side Channel 11 (RM 163.0),Upper Side Channel 21
above over flow channel A5 (RM 141.8).
I~§SLQUl)of 9
RI"I 129.3
GRiC l28.3'S 1
,~
Q '"10-31.7032 n 7.6855
51 ~5
r Z '"0.81
l~---""-"'-""""'''''--~la~----------_......Jr1'UH5!~n DlsOtftRGe:trr GOLD CftfZl<:(l0007'1 100
Appendix Figure A-3.Rating curve for predicting flow at Slough 9 at Mainstem
di scharges at Gol d Creek between 19,000 cfs and 35,000
cfs.
A...5
....§.Sloe a.At.t£L 10
1M 133.8
GR;£133.853
.....
"
~-
Q •10.38.5237 Q 9.2113sems
..2 •0.93
11+-------------10.....---------......."'"""101
r1'IIN5r~1'!OISCM"R~At SOLO CI!EEIC 1100OCl"~t
Appendix Figure A-4.Rating curve for predicting flow at Side Channel 10 at
~Mainstem discharges at Gold Creek between 19~000 cfs and
35,000 cfs •
.....
-,
A-6
-LPPtlf SHE C,....N(L.11
.RM 136.2
SRit 136.251
.....
Q •10.22.2234 n 5.5901se~.
r 2 ,.0.96
~
..J
~...
Q
!oJ
S
111cr
~..
--~l+-......-"""""'---_-_._-..,...__-_--l
:-'ft(teICM CI~Ct1mtSC .l,fcGOLD c«a;1(IIOOOO"~'lOll
.....
Appendix Figure A-5.Rating curve for predicting flow at upper Side Channel
11 at mainstem discharges at Gold Creek between 13~OOO
i"""cfs and 35~OOO cfs •
.A-·Z
~5IOE:0tAN'£L21
Rrl·110.6
GRit 110.651
I•
....
Q •10••9.1215 n 11.4362
sc "lftS
r Z •0.86
J
o
Cl
101
Appendix Figure A-6.Rating curve for predicting flow at Side Channel 21
above Channel ,AS at mainstem discharges at Gold Creek
between 20,000 cfs and 35,000 cfs.
A-a
Appendix Table A-I.Side slough and side channel water surface elevation and
flow measurements,and the corresponding mean daily
Susi-tna River discharges at Gold Creek (USGS 15292000)
used to construct rating curves for the four FAS sites.
Stream Mainstem
WSEL Flow Discharge
!"""Date Time (ft)(cfs)(cfs)
Side Slough 9 830730 0930 593.37 7.8 19,100
(Gage 128.351)840812 1455 a 593.84 44.4 19,000
820720 .._--593.92 28.0 22,900
830607 1225 593.96 89.0 23,000
830630 1030 594.00 77.4 24,700
820920 1520 a 594.15 148.0 24,000
820715 ----594.10 108.0 25,600
820623 a 594.27 182.0 27,000--..-
820918 1305 594.42 232.0 26,800
830809 1547 595.25 501.5 29,900
840825 1300 595.87 800.0 29,800
Side Channel 10 840812 1645 654.64 4.7 19,000
"!""(Gage 133.8S3)830726 1530 654.72 8.0 19,400
830803 1745 655.15 31.6 21,600
830724 1620 655.57 80.0 22,700
!"""830629 1630 655.84 93.9 26,800
I,830808 1235 656.30 266.6 26,000
830810 1120 658.26 781.3 31,900
830826 1605 657.97 803.0 31,700
Upper Side 840814 1130 681.01 12.3 16,100
Channel 11 830712 1145 681.35 54.0 19,700
(Gage 136.251)830720 0945 681.34 56.6 18,600
830727 1130 681.38 59.6 18,500
830608 1550 681.63 110.0 22,000
830629 1255 682.13 335.0 26,800
830808 1400 682.24 403.0 26,000
830810 1346 682.87 735.6 31,900
830826 1745 682.93 777.5 31,700
Side Channel 21 820919 1220 744.59 10.0 24,100
(Gage 140.657)830630 1130 744.73 10.9 24,700
·830605 1500 745.33 74.0 30,000
820917 1540 745.80 157.0 32,000
840826 1015 746.13 240.0 31,700
830809 1315 746.08 332.0 29,900
a No data
A-Q
,......
I
APPENDIX B
Benthic and Drift Invertebrate Data
B-1
APPENDIX 8
Benthic and Drift Invertebrate Data
Appendix 8 contains the invertebrate catch data for benthic and drift
samples at the four FAS sites.Appendix Table 8-1 lists the occurrence
of invertebrate taxa in the three types of samples:benthic,drift,and
juvenile'chinook salmon stomach content.Appendix Tables 8-2 through
B-5 contain drift catch data for each site.Appendix Table B...6 lists
drift densities and rates for eight invertebrate groups.Appendix
Tables B-7 through 8-10 list benthic catch data for each site.
B-2
....
Appendix Table B-1.Occurrence of invertebrates by life stage (i =i nmature ,p=pupa,a=adult)and
sample type (B=8enthos,D=Drift,F=Fish Stomach)at four sample sites,middle
Susitna River,Alaska,1984.
Upper
Slough 9 Side Channel 10 Side Channel 11 Side Channel
RM 128.3 RH 133.8 RM 136.0 RM 141.8
INSECTA
.....Protura 0
,
Collembolaa F F 0 F
Isotomidae B 0 0 B 0 B 0
Poduridae 0 0 0
Sminthuridae 0 0 0 0
f"""TOTAL Collembola B 0 F 0 F B 0 F B 0
Ephemeroptera a i a i
F 0 F
i fa i i fa i i fa i i a i
Baetidae B 0 F B 0 F B 0 F B 0 F
i i i i fa i i i i i a i
Ephemerel1idae B 0 F B 0 f B 0 F B 0 F
i i i i fa i i ia i i a i
Heptageniidae B 0 F B 0 F B 0 F B 0 F
i i i i i i i i
Siphlonuridae B B 0 B 0 F 0 F
i fa i ;ia ;i ia i i fa ;
TOTAL Ephemeroptera B 0 F 8 0 F B 0 F B 0 F
Plecopteraa i i i i i i i
0 F F 0 F B F
i i i i i ia a i a
Capnfidae 8 0 B 0 B 0 F B 0
i i i i i i i i i i
Chloroperlidae B 0 B 0 F B 0 F B F
i i i i i i ia i
Nemouridae B 0 B 0 F B 0 B....i i i f i i i i fa ;a i
Perlodidae B 0 F B 0 F B 0 F B 0 F
Pteronarcidae 0
i i i i i-Taeniopterygidae B 0 B 0 B
i i i i i i i fa ia i fa i
TOTAL Plecoptera 8 0 F B 0 F B 0 F 8 0 F
I""'"
a a a
Psocoptera 0 0 F
Thysanoptera 0 F 0 F 0 F 0 F
Hemiptera 0 0 0 F 0
Homoptera 0 F 0 F 0 F 0 F
B-3
I"""
Appendix Table 8-1 (Continued).
Upper
SLough 9 Side Channel 10 Side Channel 11 Side Channel
RM 128.3 RM 133.8 RM 136.0 RM 141.8
Neuroptera 0 0
fa a a fa a a
Coleopteraa 0 F 0 0 F D
ia f
Dytfscidae D B-i
Hypdrophflidae 0
fa a a ia a i a
TOTAL Coleoptera D F 0 0 F B 0
fa f f ipa fa i i
Trichopteraa 0 F 8 0 F 8 0
p fa-Glossosomatidae 0 0
i i i i i i
Hydropsychidae 0 F 0 0 F B
i f i f i i f ip fp i fp
Limnephil f dae B 0 F B 0 F B 0 B 0 F
f
Hydroptilidae B
f i
Rhyacophflfdae B 0
i fa f f ip i i fpa ia ip f ip
TOTAL Trfchoptera 8 0 F B 0 F B 0 F B 0 F
!"""
a a ia i a i
Lepidotera 0 0 0 F 0 F
ip a fa a a i fpa ia fp a a
Diptera a B 0 F 0 F B 0 F·B 0 F
i a ia i a a
Ceratopogonidae B 0 0 B 0 0
ip fpa fpa ip ipa ipa.fp fpa ia ip ipa ipaFoIM;Chi ronomfdae B 0 F B 0 F B 0 F B 0 F
a
Culfcidae 0
i....Dixidae 0
ip fa fp f fpa 18 i fa pa i a a
Empfdfdae B 0 F B 0 F B 0 F B 0 F
f i i i
Muscidae 0 B 0 F
i i pa ip pa i
Psychodfdae 0 F 0 8 0 B
f fpa i i ipa a f fpa i pa
Simulf i dae B 0 F B D F B 0 B 0
i
Stratiomyidae 0
i
Syrphfdae 0
ip fpa fp fp f ipa ip pa
Tfpulfdae B 0 B 0 B 0 B 0
.-ipa ipa ip fpa ipa ip ipa ipaipfpaipaip
TOTAL Diptera B 0 F B 0 F B 0 F B 0 F
a a a a a a a a
Hymenoptera 0 F 0 F 0 F 0 F
8-4
Appendix Table 8-1 (Conti nued)•
~Upper
Slough 9 Side Channel 10 Side Channel 11 Side Channel
RM 128.3 RM 133.8 RM 136.0 RM 141.8
TURBElLAR IA B B
NEMATODA B B D B D B
"""OL IGOCiAETA B D B D B D B D
.....CRUSTACEA
Amphipoda D
Cladocera B D F D
Eucopepoda B D D B D B
Podocopa 0 B D B D D
TOTAL CRUSTACEA B D F 8 D B D B D
ARACHNIDA
Acari B D 8 D B D B D
Araneae D F D F D F D F
TOTAL ARACHNIDA B D F B 0 F B 0 F B 0 F
"""OillOPODA D
GASTROPODA B 0
.-
PElECYPODA B
HYDROZOA D
a IdentHied to Order only.
B--5
Appendix Table B-2.Total numbers of invertebrate larvae and adults ( )in drift samples
collected at Slough 9.middle Susitna River,Alaska,1984.Terrestrial
insect groups and non-insect groups are not di fferentiated by larvae or
adult •
.....Head I FC-4
June iUbb August June iU~5 August
Water Fi 1tered (ft3 )13.064 •2,697 13.321 •2;805
INSECTA
Collembola
Isotomidae 5 2 6 2
Poduridae 4 1 1
Sminthuridae 4 1
TOTAL Collembola 9 2 10 4 1
-Ephemeroptera
Baetidae 19 (5)4 (1)5 (1 )4
Ephemerellidae 1 9 2 '1 2
Heptageniidae 3 7 4 4 4
TOTAL Ephemeroptera 23 (5)20 (1 )6 9 15 (1 )6
F""Plecopteraa 9 31
Capniidae 1 (1 )3
Ch 1oroper 1i dae 1 2 1
Nemouridae 1
Perl odi dae 4 6 1 1 1~Taeniopterygidae 30 38
TOTAL Pelcoptera 7 17 31 2 31 (1)42
Psocoptera 3 1
Thysanoptera 18 5 13 1 1
Hemiptera 2 2 7 2
Homoptera 2 13 1 2 2
Coleoptera 8 15 3 1
Trichopteraa 1 22 24....Hydropsychidae 7 1
Limnephi 1i dae 20 1 1 44
TOTAL Trichoptera 1 22 27 1 25 45
Lepidoptera 1 1 1
Diptera 8 (4)(3)(2)(1)
Ceratopogonidae (1 )1 (1)1 (2)
Chi ronomidae 212(268)61 (32)5(157)81 (105)37 (55)6 (86)
Empididae (1 )1 (2)(5)(1 )
Psychodidae 2
.-Simuliidae 92 (17)10 (1)4 (1 )4 (3).(1)(1)
,Tipulidae 3 (1)1 1
i
TOTAL Diptera 307(291)73 (35)9(161}87(112}38 (64)8 (88)
8-6
Appendfx Table B-2 (Contfnued).
Head I FC-4
AugustJuneiubiaAu~st June lu~5WaterFiltered(ft3 )13,064 ,i,97 13,321 ,2,805
Hymenoptera 21 30 20 12 12
OLICOCHAETA 8 5 1 2 1 4....CRUSTACEA
CTadecera 1 5 5 6 S4
Eucopepoda 11 11 8 3 8 1
Podocopa 2 1 2
~
TOTAL CRUSTACEA 12 18 14 3 16 55
ARACHNIDA
Acari 4 5 1 1 2 4
Araneae 2 1 1 1 1
TOTAL ARACHNIDA 6 6 2 2 3 4
FISH
Alevfn 1 1 1
F a Identified to Order only.
--
B-7
.....
I B-8
8-9..
Appendix Table 8-4.Total numbers of invertebrate larvae and adults ()in drift samples
collected at Upper Side Channel 11,middle Susitna River,Alaska,1984.
Terrestrial insect groups and non-insect groups a re not di fferenti ated by
~larvae or adult.
.....Head IFe-4
June tua§August June ~uJ~6 August
Water Filtered (ft3 )21,$30 •4,096 23,211 •,5.490
INSECTA
Protura a 2
Collembola 1
Isotomidae 204 2 2 76 4
Poduridae 11 3 1 2
Sminthuridae 3 5
TOTAL Collembola 220 2 2 84 5 3
Ephemeropter-a a (1 )
Baetidae 1,226 29 (1 )2 154 17 (1 )3
Ephemere 11 i dae 6 7 5 3
Heptageniidae 79 12 17 11 12 (1 )10
"...Siphlonuridae 43 3
TOTAL Ephemeroptera 1,348 47 (1)26 168 34 (3)16
Plecopteraa 1 48 3 45
Capniidae 1 (1 )1 2 (2)
Chloroperlidae 64 7 6 12 2 1
Nemouridae 64 (11)2 26 (2)1 2
Perlodidae 6 7 8 3
Pteronarcidae 2
TOTAL Plecoptera 137 (12)15 64 42 (2)8 (2).48
Psocoptera 5 2
f"""Thysanoptera 18 6 1 10 4
Hemiptera 3 2 4
Homopter-a 8 5 14 7 3 15-
Neuroptera 1
Coleopteraa 24 2 9 4
Dytiscidae 2 1 2
Hydrophilidae
TOTAL Coleoptera 26 3 11 5
Trichopteraa (1)5 3
Clossosomatidae (1)
Hydropsychidae 5 1
Li mnephi 1i dae 3 2
Rhyacophilidae 12 6
TOTAL Trfchoptera 15 (1 )12 8 1 (1)3
Lepidoptera 21 14
B-10·
Appendix Table 8-4 (Continued).
Head IFC-4
June iul§§Auaust June tUH6 August
Water Filtered (ft3 )21.530 •4;096 23.211 •5.490
~Dfpteraa 21 (20)(4)(3)13 (10)1 (6)(4 )
Ceratopogonidae 17 1 (1)(4)
011 ronomidae 883(322)73(110)113(239)572(444)68(237)131(249)
Culicidae (1)
Empididae 17 (3 )4 (7)20 (1 )(11 )1
Psychodidae 10 2 (1 )
Simulfida 90(128)14 6 24 (59)21 (5)5
Tipulfdae 63 (3 )26 (2)1 (4)
Dixidae 3 2
Muscidae 1 1
Strati omyi dae 1
Syrphidae 2 2
TOTAL Diptera 1.108(476)91(121}119(342)663(518)91(268)137(253)
Hymenoptera 29 10 8 14 9 5
NEMATODA 1 1 2 1 1
OLICOOfAETA 82 7 27 5 1
CRUSTACEA
Cladocera 4 5 5
Eucopepoda 4 3 7 5 2
Amphipoda 1 1
TOTAL CRUSTACEA ,8 8 8 10 2
ARACHNIDA
Acari 23 6 1 18 5 2
Araneae 19 1 10 1
TOTAL ARACHNIDA 42 7 1 28 6 2
CHILOPODA 3
f"'"GASTROPODA 2 1 1 1
FISH
Alevin 2 1.....Juvenile salmon 1
a Identified to Order only
.....
8-11
Appendix Table B-5.Total numbers of invertebrate larvae and adults ()in drift samples
collected at upper Si de Channel 21,mi ddl e Sus i tna River,Alaska,1984.
Terrestrial insect groups and non-i nsect groups are not differentiated by .
larvae or adult.
Head I FC-4
June Jell August June jUkba AUgust
Water filtered (ft3 )$4 9,693 S,190•
INSECTA
~Collembola
I Isotomidae 1 2 1
Poduridae 1 4
Sminthuridae 1 1
TOTAL Collembola 2 3 4 2
Ephemeroptera
Baetidae (2)
.Ephemere 11 i dae (1)3
Heptageniidae (1 )2
SiphloAuri dae 1
TOTAL Ephemeroptera 1 (2)5 (2 )
.-Plecopteraa 5
Capniidae (1)
Nemouridae 1 (1 )
Perlodidae (1 )
TOTAL Plecoptera (1 )(1)6 (1)
Psocoptera 5
.....
Thysanoptera 1 7
Hemiptera 1 1
Homoptera 1 9
Neuroptera 1
Coleoptera 2 1 1 2
Trichoptera 18
Limnephilidae 1
Lepidoptera 4
Oiptera a (1 )(1 )(2)(4)
Ceratopogonidae (1 )(3)11
O1ironOlllidae 2 (5)(8)2 (23 )4 (10)42(1047)
Empididae (19)(1 )(3).-Simuliidae 1 (11 )(1 )(3)
Tipulidae 1 (2)
TOTAL O{ptera 4 (17)(31 )2 (24)4 (16)53(1057)
r-
--
B-12
Appendix Table 8-5 (Continued).
Water Filtered (ft3 )
Hymenoptera·
HYDROZOA
Oll COCHAETA
CRUSTACEA
Podocopa
ARACHNIDA
Acari
Araneae
TOTAL ARACHNIDA
June
54
1 8
Augun
IFC-4
June ;ul~8 A5~1989,693 •
2 8 85
2
1 36
1
15 37
2 2
T7 39
-
....
a Identified to Order only.
6-13
B....J.4
-
(8-15
Appendix Table B-7.Total numbers of benthic invertebrates and the number of samples ()in
which each taxa was found at Slough '9,middle Susitna River,Alaska,1984 •
.....
7/6/84 9/9/84
18 samples 24 samples-INSECTA
Collembola
Isotomidae 1 (1)
Ephemeroptera
Baetidae 9 (5)1 (1 )
Ephemerellidae 27 (8)1 (1 )
Heptageniidae 11 (5)-Siph10nuridae -1 (1)
Total Ephemeroptera 47 (8)3 (3)
I""""
P1ecoptera
Capniidae 50 (8)
011 oroper1i dae 4 (2)3 (3)
Nemouridae -2 (1 )
Perl odi dae 11 (6)-.-Taeniopterygidae -12 (3 )
Total P1ecoptera 15 (7)67 (9)
Trichoptera
Li mneph i 1i dae 11 (4)
Rhyacophi1idae 2 (2)
Total Tr;choptera 13 (5)
Diptera 2 (2)
/'0"Ceratopogonidae 1 (1 )
O1ironomidae 60 (13)415 (19)
Empididae 4 (1 )
Simu1iidae 1 (1 )
Tipulidae -4 (3)
Total Diptera 68 (13)419 (20)
NEMATODA 1 (1 )1 (1 )
,"-OL ICOOfAETA 76 (9)15 (7)
CRUSTACEA
Cladocera 1 (1 )
Eucopepoda 3 (3)
Total CRUSTACEA 4 (3)
ARACHNIDA,-Acari (1)
!
.....
--
-B-16
Appendh Table B-8.Total numbers of benthic invertebrates and the number of samples ( )in
which each taxa was found at Side Channel 10,Middle Susitna River,Alaska,
1984.
6/26/84 9/8/84
.-32 samples 21 samples
INSECTA
Ephemeroptera
Baetidae 23 (9)7 (3)
Ephemerellidae 1 (1 )-
Heptageniidae 24 (13)1 (1 )
Siphlonuridae -3 (2)
Total Ephemeroptera 48 (15)11 (3)
Plecoptera
Capniidae 145 (15)
O1loroperlidae 8 (6)7 (6)
Nemouridae -1 (1 )
Perlodidae 7 (6)-Taeniopterygidae -3 (2)
Total Plecoptera 15 (9)156 (11)-Trichoptera
Limnephi li dae 10 (7)
Diptera 1 (1)
Chfronomidae 43 (16)157 (18)
Empididae -9 (6)
Simuliidae 4 (4)
Tipulidae -7 (5)
Total Diptera 48 (16)173 (21 )
NEMATODA 1 (1 )3 (3)-Oll GOCHAETA 6 (3)18 (9);
CRUSTACEA
Podocopa 1 (1)-ARACHNIDA
Acari ,(n
-B-17
-
-
8-18
-
B-19:
r-
I
i
r-
I
i
r-
i .
l
r-;
r-,
APPENDIX C
Results ·ofthe Multiple Regression Analysis
for Drift Data
C-l
r
-
~
I
1
r-
I
APPENDIX C
Results of the Multiple Regression Analysis
for Drift Data
Appendix C presents the results of the analysis of variance for
calculating the F values in the two multiple regression analyses.Also
shown are the results of the two sets of t tests run on the regression
coefficients.A statement of the hypothesis being tested is also
presented.
C-2
r
r-
!
Hypothesis:The numbers of drifting invertebrate at IFG-4 sites was not
dependent (rel ated)upon the numbers of drifting invertebrates at head
sites,the volume of water filtered at head sites,or the volume of
water filtered at IFG-4 sites.
1)HO:61 =62 =63 =0
HA:01;62 ;63 ;0
Table C-1.Analysis of Variance.
The critical value of F at 3 and 132 d.f.and a =0.05 is ~2.68.
Since the calculated F is 170.741 we reject the null hypothesis (H O)and
accept the alternate hypothesis (H A).
2)HO:61 =0,62 :0,63 =0
HA:61 t Me B2 ;0,B3 ;0
Table C-2.Results of Student's t-test.
r
'I
i
r
I"-
!
1
Variable Coefficient estimate
81 =0.808
8 =0.0952
83 =-0.345
Standard error
of estimate
0.093
0.058
0.085
t value
18.90
1.65
-4.05
r
I
The critical value of t at 132 d.f and a =0.05 is ~1.98.
Since the calculated t value for )?does not exceed the 'critical value
(ignore signs)we fail to reject the null hypothesis (H)of no
difference from zero for the relationship with volume of wate~filtered
C-3
.r-
I
at the head site.Accordingly,a new model was evaluated which did not
utilize x2 •The new.model was:
y =Bo +Sl x 1 +B3x3 +E
where the symbols are as defined in Section 2.3.1.
The new hypotheses tested:
1)
Table C-3.Analysis of Variance for new hypothesis.
r--
Mean sum
Source of Variation d.f.Sum of squa res ·of squares F value
r-
Regression 2 221.017 110.508 251.464
Error 133 58.448 0.439
Total 135 279.465
r-
I
I
The critical value of F at 2 and 133 d.f.and a =0.05 is s 3.07.Since
the calculated F is 251.464 we reject the null hypothesis (H O)and
accept the alternate hypothesis (H A).
2)HO:61 =0,J 3 =0
HA:61 1 0,B3 1 0
Table C-4.Results of Student's t-test for new hypothesis _
The critical value of t at 133 d.f.and «=0.05 is s 1.98.Since the
calculated t values for the two regression coefficients exceeds the
criti ca 1 value (i gnore si gns)we reject the null hypotheses (H O)of no
C-4
r-
I
,....
r
I
.r
-I
-!
difference from zero.The final linear model with estimates of
coefficients fs:
y =2.684 +O.841x 1 -O.310x 3 +E
Note,that extensive residual analysis as outl ined by Draper and Smith
(1981)and Hoaglin et ale (1983)was completed on this final model.
This analysis indicated that residuals were approximately normally
distributed,residuals were not related to either estimated values of y
or original values of x or x ;and that no one point or groups of
points unduly affected th~relat~onship (i.e.,had outstanding values of
leverage Belsley et al.[1980]).Accordingly,the model described above
is deemed "valid".
C-5
-
-
-
-I
-I
,....
I
I
-I
1
APPENDIX 0
Fonnula for Calculating the Shannon-Weaver
Diversity Index and Evenness Index
0 ..1
....
r-
I,
APPENDIX D
Formula for Calculating the Shannon-Weaver
Diversity Index and Evenness Index
Appendix D contains the formula for calculating the Shannon-Weaver
diversity 'index and evenness index (Poole 1974)used'to describe the
benthic invertebrate cOR111unities in riffl es,run,and pool habitats in
side channels and side sloughs •
0-2
1)Shannon-Weaver index (HI)
S
HI =-XP.log P.
i=1 1 2.1
.-.
!
2)
where s =number of taxa
Pi =proportion of the total number of individuals
consisting of "the ith taxa (i.e.,Family,Order)
variance of Shannon-Weaver index (var (HI»
s sXP.log2 P.-(X P.log P.)2.
i=1 1 2.1 i=1 1 2.1
.var (HI)=------------
N
r
I
--r.
r
....
where N =total number of individuals
3)standard error of HI
S.E.=J var (Ai)
4)evenness (JI)
J I·HI=10g25
0-3
-i
i
r'"I
i
i'I
r
r
APPENDIX E
Juvenile Chinook Salmon Stomach Content Data
E-1
E-2
-I
APPENDIX F
Weighted Usable Area Projection Data
F-l
F"
I
r-
I
I
r-
I
i
r
r
APPENDIX F
Weighted Usable Area (WUA)Projection Data
..
Appendix F presents invertebrate behavioral group WUA and gross area
projections for each of the study sites at various side channel and side
slough site flows.Corresponding mainstem discharges for site flows at
or above controlling breaching are also listed.
F-2
--,1 1 ]-,I 1 1 )1 I J 1
Appendix Table F·1.Projections of gross area and WUA (ft sq/1.000 ft)of benthic invertebrate habitat at Slough 9.
Site Flow Mainstem Gross Burrower Swilllller Clinger Sprawler
(cfs)Discharge Area WUA WUA WUA WUA
5 --64481 27126 1127 1403 28194
10 --70947 26912 1507 1889 33032
15 --74170 24867 1805 2265 34925
20 19695 78065 23022 2095 2625 36439
25 20275 80268 21529 2407 3006 37827
30 20762 83525 20171 2719 3394 39365
35 21182 85352 18881 3036 3779 40691
40 21554 87186 17700 3341 4157 41952
45 21886 88402 16842 3606 4501 42684
.....50 22189 89986 16020 3877 4852 43418~'
60 22721 92398 15008 4423 5570 45042
70 23182 96544 14404 5012 6313 47020
80 23588 98312 14041 5592 7019 48908
90 23952 100229 13866 6181 7761 50412
100 24283 101929 13739 6769 8497 51382
125 23998 105280 13639 8385 10539 53577
150 25598 108189 13284 10124 12790 55257
175 26117 110150 13038 12010 15086 56568
200 26575 111734 12871 14063 17471t 57715
250 27357 114982 12944 18379 21915 60254
300 28014 118473 13020 22240 24465 61942
350 28582 120769 13079 24923 24097 63457
J ])1 ]1 ..~J 1
."
I
.J:o
Appendfx Table F-1.Contfnued.
Sfte Flow Mafnstem Cross Burrower Swflllller Clfnger Sprawler
(cfs)Dfscharge Area WUA WUA WUA WUA
400 29083 122670 12492 25531 22388 64068
450 29532 124344 11711 24881 19899 63869
500 29939 128544 11339 23786 17653 62585
550 30313 129888 11505 22251 15407 60368
600 30658 131216 11486 20439 13517 57721
--sfte flow not controlled by mafnstem dfscharge
.~1 1 -J -J 1 J 1 1 1 J )1 J
Appendix Table F-2.Projections of gross area and WUA (ft sq/l.000 ft)of benthic invertebrate habitat at Side Channel 10.
Side Channel Mainstem Gross Burrower Swinmer Clinger Sprawler
(cts)Discharge Area WUA WUA WUA WUA,
5 --44519 6369 3436 4987 31787
10 19534 51396 6291 4988 6963 37662
15 20413 57069 6142 6356 8713 41667
20 21060 60975 6029 7587 10805 45103
25 21577 63253 5916 8649 13136 46919
30 22008 64655 5877 9782 15041 48343
35 22379 66581 5893 11117 16254 49622
"40 22706 67914 5951 12436 17411 50355
I
01 50 23263 70782 6182 14165 19124 52987
60 23728 73925 6233 15107 19549'55189
70 24128 78243 6783 15995 20081 58485
90 24796 85177 7400 17485 20689 63452
100 25081 88501 7851 18322 21224 65736
--site flow'not controlled by mainstem discharge
1 )1 1 I 1 )1 --1 J 1 I
Appendix Table F-3.Projections of gross area and WUA (ft sq/1.000 ft)of benthic invertebrate habitat at Upper Side Channel 11.
Site Flow HainsUm Cross Burrower Swimmer Clinger Sprawler
(cfs)Discharge Area WUA WUA WUA WUA
5 .-55198 12730 1156 1985 26663
10 --64423 13509 1711 2944 30773
15 .-70364 14171 2208 3783 34486
20 16152 71t134 14277 2741 4616 37427
25 16810 78120 13884 3239 5358 39117
30 17367 81321 13691 3776 6156 41398
35 17853 85287 13583 4335 6993 43662
40 18284 86115 13556 4803 7686 45033
45 18674 86902 13412 5222 8340 45731
"T1 50 19029 87618 13238 5610 9043 46177I
0\
60 19660 91321 13042 6391 10682 47485
70 20210 94446 13102 7273 12270 49498
80 20698 96357 13201 8263 13641 51103
90 21139 99027 13226 9327 14808 52643
100 21541 100245 13239 10323 15822 54112
110 21912 103388 13255 11261 16694 55394
1 1 1 1 1 J )
Appendix Table F-3.Continued.
Site Flow Mainstem Grollll Burrower Swll1111er Clinger Sprawler
(cts)Discharge Area WUA \VllA WUA \VllA
120 22255 104770 13296 12126 17677 56839
130 22576 106149 13277 12913 18742 57885
140 22877 107433 13285 13615 19806 59120
150 23162 108614 13245 14349 20737 59949
175 23809 111336 1~145 16113 22617 61692
200 24385 113641 12936 17314 24329 62983
225 24904 115707 12747 18263 25737 64044
250 25378 117635 12614 19315 26556 64781
."--site flow not controlled by mainstem dischargeI
.......
1 ~]J J J 11 I )1
Appendix Table F~4.Projections of gross area and WUA (ft sq/l,OOO ft)of b~nthic invertebrate habitat at Side Channel 21.
Line Site Mainstem Gross Burrower Swimmer Clinger Sprawler
No.Discharge Discharge Area WUA WUA WUA WUA
5 ~-48143 19202 692 1084 19395
10 24138 54765 21041 1133 .1552 21946
15 25009 57589 20105 1450 1952 23266
20 25647 58996 18263 1803 2481 24545
25 26152 60280 16945 2040 2777 24913
30 26572 60942 15719 2288 3061 25241
35 26933 62571 1It633 2536 3341 25516
40 27249 65457 14226 2720 3579 26066
45 27531 67779 13998 2948 3839 26710
."50 27786 70378 14194 3175 4071 27309,
CX)
60 28232 71364 13713 3615 4546 27936
70 28616 73227 13094 4025 5058 23276
80 .28952 75853 13149 4413 5577 28839
90 29251 77232 12923 4832 6078 .29503
100 29522 78424 12485 5258 6600 30284.
200 31367 86757 11417 8064 8988 35549
300 32499 89749 10853 7425 8535 35660
400 33327 92325 9897 6684 8057 34884
-~site flow not controlled by mainstem discharge
-
-
-I
!-
r-
I
APPENDIX G
Water Turbidity Data
6-1
J J 1 1 J 1 J I 1
Appendix Table G-1.Turbidity values in nephelometric turbidity units (NTU)from five locations.middle Susitna River.Alaska.1984.
Mainatem
IFG-4 Head Mainstem Discharge (cts)Breached
Location Date Time (NTU)(NTU)(NTU)at Gold Creek (Ves/No)
Slough 9 840611 2100 27 38 --8 21500 V
(River Mile 128.3)840612 2200 22 ~~a
__8
21300 V
840706 1530 124 --a 22300 V
840711 2130 152 160
__a
23100 V
840712 2130 130 156 --a 21900 V
840813 2030 100 152
__a
17600 V
840814 2000 70 l~~a --a 16100 V
840909 1150 1 --a 10600 N
Side 840613 2130 24 ~'~a --a 25900 V
Channel 840614 2100 120 --a 31500 V
10 840626 1520 136 --a __a
26600 V
(River Mile 133.8)840713 2100 138 138
__a
21200 V
840714 2130 77 ~~a
__a
21200 V
840815 2000 2 --a 15100 N
840816 2000 1 --a --a 14500 N
840908 1110 1 --a --a 10900 N
Upper 840607 2235 46 --a --a 19300 Ven,Side ,840608 2200 44 48
__a
20300 VNChannel8407072100138140--a 21900 V
11 840708 2100 142 1~~a
__a
21500 V
(River Mile 136.0)840709 1122 140 --a 21400 V
840809 2030 344 320 --a 24500 V
840810 2015 248 3~~a --a 24000 V
840823 1202 108
__a
17900 Y
Upper 840609 2100 1 --a --a 21100 NbSide84061021302~~a --a 21900 Y
Channel 840624 1140 152 --a 30000 .y
21 840709 2100 2 --a --a 21400 Nb(River Mile 141.8)840710 2130 8 l~~a --a 21200 V
840811 2000 15 --a 22500 N
840812 2000 2 --a --a 19000 N
840824 1215 66 --a --a 22700 Y
Mainstem 840531 0840 --a --a 10c 12600 a--at 840627 1300 --a --a 110c 28700 a--Gold Creek 840725 1230 --a --a 70c 22800 a--(River Mile 136.6)840823 1345 --a --a 130c 17900 a--
840928 1300 --a --a 8c 7320 a--
a No data
b At point of breaching.
c U.S.C.S (1985)Provisional Water Resources Data.Alaska.Water Year 1984 (in press).