HomeMy WebLinkAboutSUS509PRELIMINARY DRAFT REPORT
Characterization of Aquatic
Habitats in the Talkeetna to Devil
Canyon Segment of the Susitna River. Alaska
Prepared by:
Robert G. Aaserude
E. Woody Trihey and Associates
and
Jim Thiele
David E. Trudgen
Arctic Environmental Information and Data Center
University of Alaska-Fairbanks
Submitted to:
Harza-Ebasco Susitna Joint Venture
711 "H" Street
Anchorage. Alaska 99501
Hay 30. 1985
ACKNOWLEDGEMENTS
This report was funded by the Alaska Power Authority as part of the licensing
studies for the proposed Susitna Hydroelectric Project. The authors
acknowledge the following Susitna Hydro Aquatic Study Team members for their
assistance in the preparation of this report: Shelley Williams, E. Woody
Trihey and Associates, for suggestions which improved the organization of the
report; Denise Cote, Arctic Environmental Information and Data Center, for
technical editing; Bill Wilson, Arctic Environmental Information and Data
Center, for review comments; Jean Baldridge, Entrix, and Greg Reub, E. Woody
Trihey and Associates, for field data collection; Dr. Alexander Milner and
Diane Hilliard, E. Woody Trihey and Associates, for technical assistance with
the statistical analyses; Paul Suchanek, Alaska Department of Fish and Game
(ADF&G), for explanation of ADF&G substrate and cover codes; Wanda Seamster,
Arctic Environmental Information and Data Center, for graphics expertise; and
Sally Healey and Cheryl Martinez, Arctic Environmental Information and Data
Center, for diligently typing the manuscript.
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TABLE OF CONTENTS
ACKNOWLEDGDfENTS •••••••••••••••••••••••••••••••••••••••••••••••••• i
LIST OF TABLES ••••••••••••••••••••••••••••••••••••••••••••• iv
LIST OF FIGURES........................................................... vi
1. INTRODUCTION ••••••••••••••••••••••••••••••••••••••••••••••••••••••••
2.
3.
4.
5.
INVESTIGATIVE FRAMEWORK •••••••••••••••••••••••••••••••••••••••••••••
2.1
2.2
2.3
HYDROLOGIC COMPONENT ••••••••••••••••••••••••• ~ •••••••••••••••••
2.1.1
2.1. 2
2.1. 3
2.1.4
2.1. 5
Habitat Transformation Tracking •••••••••••••••••••••••••
Breaching Flow ........................................... .
Cross Sectional Geometry of Side Channel Head Berms •••••
Cross Sectional Geometry of Mainstem ••••••••••••••••••••
Evaluation of Upwelling •••••••••••••••••••••••••••••••••
HYDRAULIC CO!iPONENT ••••••••••••••••••••••••••••••••••••••••••••
2.2.1 Mean Reach Velocity •••••••••••••••••••••••••••••••••••••
2.2.2 Substrate Size ••••••••••••••••••••••••••••••••••••••••••
2. 2. 3 Channe 1 (orphology ••••••••••••••••••••••••••••••••••••••
STRUCTURAL COl-:_ JNENT •••••••••••••••••••••••••••••••••••••••••••
FUNCTION OF ANALYSES IN EXTRAPOLATION •••••••••••••••••.•••••••••••••
3.1
3.2
CONCEPT OF REPRESENTATIV E GROUPS •••••••••••••••••••••••••••••••
CONCEPT OF STRUCTURAL HABITAT INDICES ••••••••••••••••••••••••••
RESULTS AND DISCUSSION ••••••••••••••••••••••••••••••••••.•••••••••••
4.1
4.2
4.3
4.4
HYDROLOGIC COMI>ON'ENT •••••••••••••••••••••••••••••••••••••••••••
4 .1.1
4.1. 2
4.1.3
4.1.4
4.1. 5
Habitat Transformation Tracking •••••••••••••••••••••••••
Breaching Flow ••••••••••••••••••••••••••••••••••••••••••
Cross Sectional Geometry of Side Channel Head Berms •••••
Cross Sectional Geometry of Mainstem ••••••••••••••••••••
Evaluation of Upwelling ••••••••••••••••••••••••••.••••••
HYDRAULIC COMPONEN'T ••••••••••••••••••••••••.•••••••••••••••••••
4.2.1
4.2.2
4.2.3
Mean Reach Velocity •••••••••••••••••••••••••••••••••••••
Substrate Size ••••••••••••••••••••••••••••••••••••••••••
Channel Morphology ••••••••••••••••••••••••••••••••••••••
STRUCTURAL COMPONENT •••••••••••••••.•••••••••••••••••••••••••••
DEVELOPMENT OF REPRESENTATIVE GROUPS •••••••••••••••••••••••••••
CONCL USIONS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••
4
6
10
13
13
14
14
15
15
17
18
18
20
21
23
27
27
27
32
34
38
40
42
42
45
46
49
51
63
LITERATU'RE CITED.................................................... 65
-ii -
TABLE OF CONTENTS
(coot' d)
A.?PENDICES.......................................................... 67
APPENDIX 1 -Specific Areas Delineated on 23000 cfs Aerial
Photography. . . • . • . • . . . • . • . • . • . • • . . . • . • • . . . . • . . . . . . 6 7
APPENDIX 2 -Methodology....................................... 77
APPENDIX 3 -Aquatic Habitat Transformations of Specific Areas
of the Middle Susitna River at Several Mainstem
Discharges Referenced to 23000 cfs •••••••••••••.•• 115
APPENDIX 4 -Approximate Breaching Flows of Specific Areas
of the Middle Susitna River ••••••••••••••••••••••• 120
APPENDIX 5-Fish Observations ••••••••••••••••••••••••••••••••• 123
-iii -
Table No.
1.
") ...
3.
4.
5.
LIST OF TABLES
Description of Habitat Transformation Categories ••••••••••.
Number of specific areas in each habitat transformation
category by evaluation mainstem flow, referenced to
23000 cfs ................................................. .
Curve slope classes of plots of wetted top width versus
discharge from measurements made at channel head berms
at 46 specific areas in the Talkeetna to Devil Canyon
segment of the Susitna River •••••••••••••••••••••••••••••••
Stag increase at selected cross sections in the Talkeetna
to u ~il Canyon segment of the Susitna River as mainstem
disc' targe increases from 9700 to 23400 cfs •••••••••••••••••
Summary of the specific areas that possess upwelling in the
Talkeetna to Devil Canyon segment of the Susitna River •••••
Page No.
12
29
38
39
41
6. Definition of subsegments within the Talkeetna to Devil
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Canyon segment of the Susitna River........................ 48
Major side channel complexes of the Talkeetna to Devil
Canyon segment of the Susitna River ••••••••••••••••••••••••
Representative Group I .••••••••••••••••••••••••••••••••••••
Representative Group !! •....•••••......••••................
Representative Group III •.........•.........•......••......
Representative Grou t> IV ....•..•...............••.••........
Representative Gr oup V ••.•.••.•.•..••.....••..•.•.•.•.•..••
Representative Group VI •.•••...•.••.•......•.••...•.•••••••
Representative Group VII ••••••.•••••••••••....•••••.•...••.
Representative Group VIII ••••••••••••••••••••••••••••••••••
Representative Group IX •.•••.••••••.••.•••••••.••• , •••••••.
Representative Group X ••••••••.•••••••.•••••••••..•••••••••
-iv -
48
53
54
55
56
57
58
59
60
61
62
LIST OF TABLES
(cont'd)
Table No. Page No.
18. Use of black and white aerial photography in characteriza-
19.
20.
21.
22.
23.
24.
tion of aquatic habitat.................................... 80
The relationship between the height (h) that water climbs
a staff when held perpendicular to the flow and mean
reach velocitY•••••••••••••••••••••••••••••••••••••••••••••
Cover suitability criteria recommended for use in modeling
juvenile chinook habitat under clear water conditions ••••••
Dominant cover/percent cover rating factors ••••••••••••••••
Channel morphology rating factors ••••••••••••••••••••••••••
Substrate size/embeddedness rating factors •••••••••••••••••
Strea~side vegetation rating factors •••••••••••••••••••••••
91
95
96
97
98
99
25. Structural habitat variables and their corresponding
weighting factors.......................................... 99
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LIST OF FIGURES
Figure No.
1. Flow chart for the extrapolation methodology •••••••••••••••
2. Schematic of aquatic habitat components and descriptive
variables ................................................. .
3. An indistinct side channel that becomes a distinct side
channel with decreasing mainstem discharge •••••••••••••••••
4. Examples of continuous and discontinuous subsegments •••••••
5. Flow chart for the stratification pathway of the extrapola-
t ion methodology ..........•.........••.......••............
6. Lateral shift of weighted usable area (WUA) curve of a
modeled specific area to synthesize the WUA curve of a
nonmodeled specific area that has a different breaching
Page No.
3
5
9
22
25
flow....................................................... 26
7.
8.
9.
10.
Adjustment of the weighted usable area (WUA) curve of a
modeled specific area being used to synthesize the WUA ·
curve of a nonmodeled specific area to account for dif-
ferences in structural habitat quality between the two
specific areas •••••••••••••••••••••••••••••••••••••••••••••
Flow chart for classifying the transformation of aquatic
habitat types between two flows (categories 0-10) ••••••••••
Number of specific areas in each habitat transformation
category at various mainstem flows •••••••••••••••••••••••••
General relationship between breaching flow and habitat
type in the Talkeetna to Devil Canyon segment of the
Susitna River ........•.........•.•....••...................
11. Representative vetted top width versus discharge plots for
26
28
30
33
each category of curve slope............................... 35
12. Cross sectional geometry at the head berm of two channels
having the same breaching flow. Note how differences in
cross sectional geometry affects the rate of wetted surface
area development for a comparable increase in mainstem
stage...................................................... 37
13.
14.
15.
The reiationship between height (h) and mean reach velocity
as depicted by the rise of the water column against a staff
held perpendicular to the flow •••••••••••••••••••••••••••••
Structural habitat index form ••••••••••••••••••••••••••••••
Habitat inventory form ••..••••••.••.•••••••••••.••••..•...•
-vi -
91
100
102
1. INTRODUCTION
The Alaska Power Authority has proposed the construction of two dams on the
Susitna River. Construction of the proposed hydroelectric project will alter
the flow regime downstream '-'f the dams which will result in corresponding
changes to the quality and quantity of fish habitat. The most pronounced
influences of the project are expected to occur in the Talkeetna to Devil
Canyon segment of the Susitna River (the Middle River). Two major
tributaries, the Talkeetna and Chulitna Rivers, will buffer the impacts of the
project downstream of Talkeetna.
To evaluate the effects of constructing the project on juvenile salmon
habitat, it is necessary to document natural conditions. Towards this
objective, the Alaska Department of Fish and Game (ADF&G) and E. Woody Trihey
and Associates (EWT&A), in a cooperative program, have applied fish habitat
modeling techniques at 35 sites in the Middle River. These models provide
insight to the response of aquatic habitat quality and quantity to discharge
at these sites.
The Middle River is a large, frequently braided or split channel river with
numerous sloughs, side channels, and tributaries providing the moat important
habitat for juvenile salmon (Schmidt et al. 1984). The areas of the Middle
River that have been modeled amount to only a fraction of the total habitat
available in the Middle River. It was impractical and coat prohibitive to
model the entire Middle River.
- 1 -
To determine the response of aquatic habitat quality an d quantity t o discharge
for the entire Middle River, it is necessary to extrapolate results from
modeled sites to nonmodeled areas of the river. Extrapolation entails
quantifying habitat, ~-ratifying (grouping) habitats that are homogeneous, and
forecasting habitat response to discharge through computer simulation. The
integration of these three extrapolation components will allow the evaluation
of the effects of with-project flows on aquatic habitats in the Middle River.
This evaluation will be considered in the negotiation of a flow regime for the
proposed Susitna Hydroelectric Project.
The focus of this report is on the stratification of aquatic habitats through
habitat inventory and aerial photo interpretation procedures into groups that
are hydrologically, hydraulically, and morphologically homogeneous. These
analyses and procedures represent one component of the extrapolation
methodology depicted in Figure 1.
- 2 -
Quantification
Quantify surface areas
by habitat type in the
Middle River for each
flow for which aerial
photography is avail-
able to determine the
surface area response
tc mainstem discharge.
Stratification
Use available morpho-
logic, hydraulic, and
hydrologic information
to stratify aquatic
habitats into homoge-
neous groups.
Integration
For each target species/
life stage:
Integrate the quantifi-
cation, stratification,
and simulation compo-
nents to determine the
aquatic habitat response
to discharge for the
entire Middle River.
Simulation
Simulate the response
of aquatic
quality to
with habitat
habitat
discharge
modeling
techniques at selected
areas of the Middle
River.
Figure 1. Flow chart for the extrapolation methodology.
-3 -
2 . INVESTIGATIVE FRAMEWORK
The investigative framework pursued in this paper is founded on the resolution
of aquatic habitat into three components: (l) water (hydrologic); (2) poten-
tial energy (hydraulic); and (3) channel structure (Figure 2). Aquatic
habitat was resolved in this manner to: (l) provide focus to the development
of analytical procedures; (2) organize the data base into a manageable format;
and (3) be consistent with the framework established in previous studies.
Primarily two data sources were used in the aquatic habitat characterization
process: a habitat reconnaissance data base (based on field studies); and
aerial photography. The investigators incorporated additional information
from the Alaska Department of Fish and Game's (ADF&G) habitat modeling
program, ADF&G fish utilization studies, and personal communications with
ADF&G field personnel into their analyses.
Black and white aerial photography was available at Middle River discharges of
5100, 7400, 9000, 10600, 12500, 16000, 18000, 23000, and 26900 cubic feet per
second (cfs), as measured at the U.S. Geological Survey (USGS) Gold Creek
gaging station. The 23000 cfs photography represents average summer
conditions and was used in this study as the "reference flow."
- 4 -
Water
Variables
• • Source
• Supply
Aquatic Habitat
Components ...
Potential Hydraulic
Energy
I
Variables
' • Slope
• Water Velocity
• Water Depth
• Substrate Size
• Channel Morphology
Variables
t
• Substrate Size
• Cover Type
• Percent C~ver
• Substrate Embeddedness
• Channel Cross Sectional
Geometry
• Streamside Vegetation
Figure 2. Schematic of aquatic habitat components and descriptive Vlrlables.
-5 -
All wetted surface area at the reference flow which was not part of t he main
channel of the Middle River, or mainstem, was separated into specific areas.
Side channels, side sloughs, and upland sloughs generally constituted a
specific area. Occasionally a large side channel or slough was subdivided
into two or more specific areas due to differences in habitat character. In
addit1~n to these nonmainstem habitats, some representative mainstem habitats
were delineated as specific areas. Each specific area was referenced to a
river mile (RM) and the side of the river it is on looking upstream: left (L),
right (R), or middle (M) if between two mainstem forks. A total of 172
specific areas were delineated and are shown in Appendix 1.
2.1 P.YDROLOGIC COMPONENT
The suitability of ~ given specific area of the Middle River as aquatic
habitat is largely dependent on the quantity and quality of water supplied to
the site. This hydrologic component of aquatic habitat was evaluated for each
specific area using up to five indices.
Klinger and Trihey (1984) delineated and quantified six habitat types in the
Middle River from black and white aerial photos taken when Middle River
discharges at Gold Creek were 9000, 12sno, 16000, and 23000 cfs. Water source
and morphology were the principal variables used to discriminate between
habitat types. Descriptions of each habitat type are as follows:
Mainstem habitats are those channels of the riv er that convey more than
approximately 10 percent of the total flow at a given site. During the
open water season these channels are characterized by turbidity from
glacial meltwater.
- 6 -
Side channel habitats are those channels of the river that convey l ess
than approximately 10 percent of the total flow. During t he open water
season these channels are characterized by turbidity from glac i al
meltwater.
Side slough habitats contain clear water. Local surface water runoff and
upwelling groundwater are the primary sources that supply these habitats.
Side sloughs have nonvegetated upper thalwegs that are overtopped during
periods of moderate to high mainstem discharge. Once overtopped, side
sloughs are considered side channels.
Upland sloughs are clearwater habitats that depend upon upwelling
groundwater and/or local runoff for their water scurces. Upland sloughs
have vegetated upper thalwegs that are seldom overtopped by mainstem
discharge.
Tributary mouths are clearwater habitats at the confluences of
tributaries. where clearwater mixes with turbid water. In the suDDDer
these habitats are readily apparent as clearwater plumes that extend into
the turbid glacial flow of the mainstem or a side channel. The size of
the plume is a function of tributary discharge and mainstem st a ge.
Tributary mouth habitats can also occur in the tributary channel as a
result of mainstem stage causing a backwater at the tributary mouth. If
a backwater occurs. tributary mouth habitat extends into the tributary
channel to the upstream extent of the backwater.
-7 -
Tributary habitats are clearwater reaches of tr i butary streams upstream
of the tributary mouth habitats .
Subhabitat types were required by this study to be consistent with t he
resolution provided by aerial photography and are as follows :
Indistinct mainstem habitats occur at the margins of some mainstem
channels. In the 23000 cfs photography they appear to be an integral
part of a mainstem habitat. In photographs taken at lower flows,
however, they are distinct channels separa ted from the mainstem by gravel
bars or are shallow expanses (shoals) at the margins of a mainstem
channel (Figure 3).
Indistinct side channel habitats occur at the margins of some mainstem
and side channels. In th~ 23000 cfs photography they appear to be an
integral part of a mainstem or side channel habitat. In photographs
taken at lower flows, however, they are distinct channels separated from
the mainstem or main side channel by gravel bars or are shallow expanses
(s hoals) at the margins of the mainstem or side channel.
- 8 -
Ir.distlnct specific area across from tributary mouth
(TM) habitat of Indian River at a mainstem discharge of
23000 cfs
Distinct specific area 138.8R across f ro~ tributary mouth (TM)
habitat of Indian River at a mainstem discharge of 23000 cfs
Figure 3. An indistinct side channel that becomes a distinct
side channel with decreasing mainstem discharge.
-9 -
2.1.1 HABITAT TRANSFORMATION TRACKING
Habitat type may change at an individual site as mainstem stage fluctuates.
The most c011111on habitat transformation occurs when a side channel becomes a
side slough as mainstem stage recedes to a level that prevents the flow of
turbid mainstem water through the side channel entrance. Another COllllllOn
transformation, with less obvious changes in habitat quality, occurs when
mainstem habitat becomes side channel habitat as a result of decreasing
mainstem stage. These habitat transformations are significant because they
demonstrate the direct relationship between habitat type and quality and
mainstem discharge. The development of a methodology to monitor habitat
transformations in reference to discharge is thus a prerequisite to the
assesgment of the response of aquatic habitat quality to mainstem flow.
Habitat transformations resulting from lowered mainstem flow are of particular
interest to this study since the proposed hydroelectric facility would result
in substantially decreased flows during the su111111er . It was assumed that the
distribution of aquatic habitat within the Middle River is constant for any
given mainstem discharge. This is a valid assumption since the river has
undergone very little change between 1949 and 1980 (AEIDC, 1984). Field
observations also support this assumption. Thus, examination of aerial
photographs in a decreasing order of mainstem discharge is indicative of how
aquatic habitat responds to a steady decrease in discharge.
Aerial photography of the Middle River for mainstem discharges of 5100, 7400,
9000, 10600, 12500, 16000, 18000, and 23000 cfs were used in the analysis.
Hab i tat transformations at each specific area were monitored between any two
flows through photo comparison.
-10 -
El ev•n habitat tunsfot"'llation categories define the types of habitat tran s-
formation that a specific area might undergo as mainstem dischar ge dec l i nes
(Table 1). These categories provide a use ful means to systematically evaluate
the hydrologic component of aquatic habitats as mainstem discharge decreases
from the reference flow of 23000 cfs through each evaluation flow down t o 5100
cfs. The total number of specific areas within each transformation category
at each evaluation flow reflects the general trend of the response of aquatic
habitat to mainstem flow.
Individual specific areas can be characterized by the sequence of habitat
transformations that occur as mainstem discharge decreases from 23000 cfs to
5100 cfs. The importance of the category sequence in describing and
classifying aquatic habitat is most pronounced for sites that are strongly
influenced by the hydrologic component. as compared to the hydraulic and
structural components. For e~ample. upland slough habitats are strongly
influenced by their relative isolation from a mainstem water supply (hence. by
their hydrologic component) and could likely be discriminated from other
habitat types by their category sequence alone (an unchanging Category I).
Procedures for sequentially monitoring hab i tat transformations between the
23000 cfs photography and the photography at lower discharges are discussed in
Appendix 2.
-11 -
Table 1. Description of Habitat Transformation Categorie3*
Category 0
Category 1
Category 2
Category 3
Category 4
Category 5
Category 6
Category 7
Category 8
Category 9
Category 10
Tributary mouth habitats that persist as tributary mouth
habitat at a lower flow.
Upland slough and side slough habitats that persist as the same
habitat type at a lower flow.
Side channel habitats that transform to side slough habitats at
a lower flow and possess upwelling which appears to persist
throughout winter.
Side channel habitats that transform to side slough habitats at
a lower flow but do not appear to possess upwelling that
persists throughout winter.
Side channel habitats that persist as side channel habitats at
a lower flow.
Indistinct mainstem or side channel areas that transform into
distinct side channels at a lower flow.
Indistinct mainstem or side channel habitats that persist as
indistinct areas at a lower flow.
Indistinct mainstem or side channel areas that transform to
side slough habitats at a lower flow and possess upwelling that
appears to persist througnout winter.
Indistinct mainsteu or side channel habitats that transform to
side slough habitats at a lower flow but do not appear to
possess upwelling which persists throughout winter.
Any water course that is wetted that dewaters or consists of
isolated pools without habitat value at a lower flow.
Mainstem habitats that persist as mainstem habitat at a lower
flow.
*Habitats were based on a reference flow of 23000 cfs.
-12 -
2. 1. 2 BREACHING FLOW
Breaching flow is defined as the mainstem discharge at which the water sur f a c e
elevation in the main channel is sufficiently high to overtop the head berm of
a peripheral channel and thus allow mainstem water to flow through the area.
The frequency of flow events in a specific area is cl product of the sites
breaching flow and the frequency of flows in the mainst em. Not all specific
areas have readily identifiable breaching flows, and some areas are breached
gradually over a range of mainstem flows. For example, the overtopping of
mainstem and side channel shoals is frequently a subtle process; water
laterally inundates these areas with increasing stage. Water seldom overtops
heads of upland sloughs because of their elevation relative to the mainstem.
Mainstem channels are always breached. The procedure used to determine
breaching flows is included in Appendix 2 .
2.1.3 CROSS SECTIONAL GEOMETRY OF SIDE CHANNEL HEAD BERMS
Just as breaching flow is a descriptor of flow frequency in a specific area,
the cross section al geometry of the channel at the head berm determines flow
magnitude at the site. Breachi ng flow and channel geometry might thus be
considered an index of what would normally be termed climatic and basin
characteristics in conventional basin nydrology. The analogue to a
responsive, so-called "flashy", drainage basin would be a side channel with a
broad, relatively gentle-sloped head bem. Such a channel would turn "on" and
"off" much more suddenly than a channel with a relatively narrow and inc ised
cross sectional geometry. This is due to the much greater increase in cross
sectional area at the entrance with the same increase in mainstem stage.
Increases in chann el flow are directly proportional to increases in cross
-lJ -
sectional area. The response of site flow to mainstem discharge is reflected
in the corresponding response of the top width of wetted surface area at the
channel entrance. Procedures for studying the cross-sectional geometry of
channel head berms using the aerial photography are described in Appendix 2.
2.1.4 CROSS SECTIONAL GEOMETRY OF MAINSTEM
A regional analysis of cross sectional geometry in the mainstem was performed
in conjunction with the site-specific analysis of channel geometry. The rate
of change in mainstem water surface elevation to an incremental increase in
discharge varies between subsegments. A subsegment of the mainstem that is
constricted will have a steeper stage/discharge relationship than a la!ss
confined subsegment. The effect on side channels adjacent to constricted
areas is an increased responsiveness of site flows to incremental changes in
mainstem discharge. The opposite is true for side channels associated with
subsegments where the mainstem stage/discharge relationship is flatter. A
description of this analysis appears in Appendix 2.
2.1.5 EVALUATION OF UPWELLING
The presence of an upwelling groundwater source that persists through winter
is the most important habitat variable influencing the selection of spawning
areas by chum salmon (Oncorhynchus keta) (Estes and Vincent-Lang 1984).
Upwelling also has a positive influence on the success of overwintering
juvenile chinook salmon (0. tshaw1tscha) and on egg-to-fry survival for chum
salmon (Vining et al. 1985). A description of the procedures used to identify
the presence of upwelling at a specific area appears in Appendix 2.
-14 -
2. 2 HYDRAULIC COMPONENT
The hydrologic component of an aquatic habitat may indi cate favorab l e
conditions for fish when in fact the site's suitability f~r fish is limited by
hydraulic conditions, such as high velocities. The energy-related
environmental variables that describe the hydraulic component were evaluated
primarily through field observations. Statistical analyses to correlate the
variables that make up the plan form, or physical layout of a site were also
performed. These analyses were limited to 70 of the 172 specific areas and
the results serve as supporting evidence to results obtained from field
observations.
In an open channel, gravity provides the energy to move water and sediments
downstream. Slope is the conventional index of the rate of this potential
energy expenditure. Because of the large n1.1mber of side cham.els, it was
impractical to determine the slope of each chann el by differential leveling;
therefore . three indices of hydraulic energy were used in characterizing
specific areas : (1) estimated and measured mean reach velocity; (2) dominant
bed material size; and (3) channel morphology.
2. 2. 1 MEAN REACH VELOCITY
Mean reach velocity offers the best estimate of channel slope and has the
additional advantage of being a significant index of habitat quality. The
weakness of mean reach velocities as an index of slope is their flow
dependence. A comparison of mean reach velocities of severa l individual
channels is meaningful only if the relationship between mean ·~each velocity,
site specific discharge, and mainstem discharge is understood. Generally it
is necessary to collect mean reach velocity data at several mainstem and site
-15 -
specific discharges to adequately describe t h is relationshi p. Howe v er, site
specific breaching flow defines the highest mainstem f low in which site
specific discharge and mean reach velocity have a magnitude of app r oximately
zero. Breaching flows can thus be used to normalize mean reach velocity
values with respect to mainstem disch.<lrge and provide a basis for comparing
velocities of specific aceas that have different breaching flows. This does
not account for all the variability in velocity between specific areas caused
by factors other than differences in channel bed slope, but it accounts for
the variability in velocity at a given mainstem discharge attributed to
differences in breaching flow between speci fic areas. Other variables, such
as differences in channel bed roughness (n, dimensionless) and hydraulic
radius (R, in feet), affect the relationship between velocity (V, in feet per
second (fps)) and channel bed slope (S, in feet per feet). Channel bed
roughness is an empirical energy loss coefficient and the hydraulic radius is
a function of stage and channel cross sectional geometry, although for ~ide
channels it is effectively dependent on depth of flow. Mannings' Equation
relates the variables as follows:
Although mean reach velocity alone is an unsatisfactory index of the hydrauli·:
energy potential at each individual channel, velocities used in conjunction
with corroborating evidence, such a s substrate size and channel morphology,
reveal much about channel hydraulics .
-16 -
2.2.2 SUBSTRATE SIZE
Substrate, or bed material size. is also related to channel slope as can be
deduced from tractive force theory (Chow 1959).
T • WRS
where T • tractive force, pounds per square foot (psf)
W • unit weight of water, pounds per cubic foot (pcf)
Tractive force is the force that water exerts on the channel bed. It can be
thought of as a scour force. The threshold size of bed material that can be
moved 1 s directly proportional to T. Bed material sizes larger than the
threshold size associated with a typical high flow event would theoretically
make up the substrate.
The elevation, configuration, and orientation of head berms strongly affect
the composition and size range of sediments delivered by mainstem flow into
side channel areas. Local geology and alluvial deposits also influence the
substrate composition of side channel beds. Smaller suspended sediments,
skimmed from the upper portion of the mainstem water column, tend to dominate
the sediment load entering side channels.
Despite these considerations, characteristic bed material size can be useful
in the assessment of available energy in individual Lhannels. It appears that
the sediment in large side channel and mainstem rearing habitats of the Middle
River is limited by available sediment and not by the capacity to transport
sediment (Williams 1985). Large substrate would therefore suggest a steep
channel gradient. Accumulation of fines in side channels and side sloughs is
indicative of a mild (or low energy) channel slope.
-17 -
2.2.3 CHANNEL MORPHOLOGY
Channel morphology is the least direct index of instream hydraulics that was
considered in the analysis. The rationale for its use is that the form of a
river is a function of river processes. River reaches •mdergoing similar
processes would thus be expected to :iisplay similar form. There is little
precedent in the literature concerning the relations between conventional
morphological indices of river form, such as sinuosity or radius of curvature,
and site-specific characteristics of individual side channels in a split
channel or braided river such as the Susitna. Nonetheless, careful inspection
of aerial photography reveals considerable evidence of r epetitive form
throughout the Middle River.
Specific areas may be grouped through statistical analyses that focus on
correlating the morphologic variables that make up the areas plan form (such
as channel length, channel width, and channel sinuosity). Statistics may also
be applied to ider.t ify the variable that most strongly defines each group.
Descriptions of the analyses and procedures for each of the a spects of the
hydraulic component are discussed in Appendix 2.
2.3 STRUCTURAL COMPONENT
In the extrapolation methodology , aquatic habitat quality indices will be
extrapolated from modeled specific areas to nonmodeled specific areas that
they represent (i.e., same homogeneo\.IS group). Site-specific hydrologic and
hydraulic indi ces are a rational approach to defining representativeness in
terms of instream hydraulics. However, this concept of representativeness
ignores the variation in aquatic habitat quality that results from differences
-18 -
in nonhydraulic attributes between specific areas. For this reason, it is
necessary to incorporate the structural component. This was accomplished through
structural habitat indices (SHI).
Six variables were used in the develop~ent of a structural habitat index for
each specific area: (1) dominant cover type; (2) percent cover; (3) dominant
substrate size; (4) substrate embeddedness; (5) chan ne~ cross sectional
geometry; and (6) streambank vegetation. These variables were characterized
for each specific area with data from the habitat reconnaissance surveys and
aerial photography, as detailed in Appendix 2. The formula for synthesizing
each of these variables into a single value (i.e., SHI) is also detailed in
Appendix 2.
-19 -
3. FUNCTION OF ANALYSES IN EXTRAPOLATION
In a cooperative program to study the relationship between mainstem discharge
and the quality and quantity of fish habitat, ADF&G and EWT&A selected
35 sites in the Middle River to represent a spectrum of aquatic habitats. An
extensive data collection program provided the basis for developing c omputer
models to describe habitat response to mainstem discharge at each of thl!se
1 sites. Three modeling techniques were used: (1) the Instream Flow Group's
(IFG) habitat model (Hilhous et al. 1984); (2) a habitat model (RJHAB)
developed by ADF&G (Schmidt et al. 1984); and (3) a direct ~nput variation of
the IFG habitat mod•l developed by EWT&A. Tributary habitats were not
evaluated because they would not be affected by an altered mainstem flow
regime. Tributary mouth habitats are more a function of hydraulic mixing
phenomena than open channel hydraulics, and the modeling techniques are not
well-suited to these habitats.
Inherent in each of the habitat models is a hydraulic model used to describe
site-specific depth and velocity distributions. There are approximately 150
unique side channel areas in the Middle River. The development of a hydraulic
model for each of these channels was impractical and the cost, prohibitive.
The investigators used less data-intensive indices of channel hydraulics to
characterize nonmodeled sites to provide a basis for discriminating
homogeneous river subsegments that could be represented with a modeled site
for extrapolation.
1 Now known as the Instream Flow and Aquatic Systems Group.
-20 -
In the application of the IFG's instream flow incremental methodology (IFIM)
to a sinale channel river, aquatic habitat response to discharge functions are
routinely extrapolated from representative reaches to river subsegaents that
have been discriminated on the basis of their hydrologic, hydraulic, and
morphologic homogeneity. The identification of homogeneous river subsegments
in a split channel or braided river as larae as the Susitna is considerably
more complex.
3.1 CONCEPT OF REPRESENTATIVE GROUPS
Anadromous salmonids are the principal study species in the Susitna River.
Their utilization of aquatic habitats is concentrated in side channels,
sloughs, tributary mouths, and tributaries (Schmidt et al. 1984). Homogeneous
subsegments should be differentiated to provide the resolution and focus
necessary to develop aquatic habitat descriptions that are consistent with the
utilization patterns of targeted study species.
Klinger and Trihey (1984), in their study of aquatic habitat response to
mainstem discharge in the Middle River, noted that the spatial distribution of
side channel and side slough habitats was strongly influenced by discharge.
The dependence of habitat types on discharge, coupled with their sporadic
location throughout the Middle River, effectively precludes the identification
of continuous homogeneous subsegments, as is the convention in the study of
single channel rive r systems. A homogeneous subsegment of the Middle River
will be, instead, a composite of discontinuous specific areas that were judged
to be hydrologically and hydraulically similar \iigure 4). In the context of
this report, such a composite subsegment is termed a representative Jroup.
-21 -
Figure 4 . Examples of continuous and discontinuous subsegments.
-22 -
The development of representative groups appears as the fifth step in the
stratification pathway of the extrapolation methodology flow chart depicted in
Figure 5.
3.2 CONC~PT OF STRUCTURAL HABITAT INDICES
The basic premises behind the concept of structural habitat indices are
simple. If two channels have comparable hydraulics and different habitat
values, then the difference in habitat va~ue must be attributed to differences
in channel structure. Outwardly, this is a simplistic conclusion which does
not address the possible effects of differences in water quality, nutrient
loading, site locatioL, and numerous other environmental variables. However,
when a judicious evaluation is made between sites within the same stream
subsegment, many of these variabl~s can be considered constant or of
secondary, perhaps minor, importance. This reasoning provides the
justification for many habitat improvement projects which utilize instream
structures. Structural habitat index values are used as relative indices of
structural habitat quality for specific at ~as within the same representative
group.
In the extrapolation methodology, weighted useable area (WUA) versus discharge
functions will be synthesized for nonmodeled specific areas using the WUA
function from a modeled specific area(s) within the same representative group.
The investigators will adjust the WUA curves for nonmodeled sites in two ways.
Laterally shit . ·~g the WUA curve either right or left will normalize the curve
on the basis of bre aching flow (Figure 6). To account for differences in
structural habitat quality, the ordinates of the WUA curve are multiplied by
-23 -
the ratio of non.modeled to modeled specific area SHis (Figure 7). I n th i s
manner, synthetic WUA versus discharge cur-ves can be devel o ped f or eac h
nonmodeled specific area within each representative group.
-24 -
Stratification Pathway of the
Extrapolation Methodology
Stretlflcetlon Pethwey
• Identify habitat types Important to study species.
• Delineate specific areas of homogeneous aquatic habitat type on
aerial photo plates.
• Conduct reconnaissance-level survey of aquatic habitat at each
specific area.
• Analyze aerial photography and habitat reconnaissance data base
to describe hydrologic, hydraulic, and structural components of
each specific area.
• Stratify specific areas Into Representative Groups using available
hydrologic and hydraulic information.
• Develop Structural Habitat Indices for each specific area Including
modeled sites using the habitat reconnaissance data base.
Quentlflcetlon +
Pethwey ~ lntegretlon
"""""' Slmuletlon
aPethwey
The following steps are completed for each target species/life
stage.
• Use the weighted usable area (WUA) versus discharge curves of a
modeled specific area to synthesize the WUA versus discharge
curve for a nonmodeled specific area within the same Represent·
atlve Group. Shift the curve laterally to compensate for differences
in breaching f low between a modeled and nonmodeled specific
area. Adjust the WUA curve vertically using the ratio of structural
habitat indices to account for dlf ~erences in structural habitat
quality between modeled and nonmodeled specific areas.
• Calculate the amount of habitat present within each specific area
using surface area and habitat quality Indices for each malnstem
evaluation flow.
• Sum the amount of habitat estimated for all specific areas within
each Representative Group for each mainstem evaluation flow .
• Sum the amount of habitat estimated for all Representative Groups
for each malnstem evaluation flow to forecast Middle River habitat
response to flow variations.
Figure 5. Flow chert for the atr1tlflc1tlon p1thw1y of the extr1pol1tlon
methodology
-25 -
-N -L.... ......,
Figure 6.
IIIEACHIIIC FLOW
SHIFT
~---~!>1
I I
I I
I
I
--~ -""' : \
\
\
\
" '
MA I NSTEM Q <CFS)
Lateral shift of weighted usable are~ (WUA) curve of a modeled
specific area to synthesize the truA curve of a nonmodeled specific
area that has a different breaching flow,
----MOOELED SPECifiC MEA
=-= ~ == 11011-t«))[L£0 SPECIFIC MEA ·-STRUCTURAL HAIITAT
QUAL I TY AO.IUS1li£NT
~-..... --'
----------
\
\
\
\
MAINSTEM Q <CFS)
Figure T.-· xAd-;:n-jo.uiist,-;m""e'"'nr.-ltrronr....,.t~hr'ller-t:'lw ... e""lgh~ usabl-e-area-(HUA) curve-ef a meddetl-~~,----
specific area being used to synthesize the WUA curve of a non-
modeled specific area to account for -differences in structural
habitat quality between the two specific areas,
-26 -
4. RESULTS AND DISCUSSION
Results and discussion pertaining to the characterization of each aquatic
habitat component will be presented in the order of their development :
hydrologic, hydraulic, and structural. The application of these habitat
characterizations in the development of representative groups and structural
habitat indices will follow.
4. 1 HYDROLOGIC COMPONENT
The hydrologic component of aquatic habitat is described by habitat
transformations, breaching flows, cross sectional geometry of the head berm,
cross sectional geometry of the mainstem, and upwelling. Of these
descriptors, habitat transformations, breaching flows, and upwelling were the
most useful for characterizing aquatic habitat. The usefulness of the cross
sectional geometry indices was limited by the lack of available information .
4.1.1 HABITAT TRANSFORMATION TRACKING
The methodology for tracking habitat transformations between 23000 cfs and
9000 cfs is depicted in the flow chart of Figure 8. It should be noted that
the criteria can be applied between any two mainstem flows. However, for
consistent evaluation, the 23000 cfs photography was used as the reference fo L
monitoring transformations apparent in lower flow aerial photography.
-27 -
WETIED AREA OF SIT E
@ 23 ,000 CFS
I
CLEAR WATER TU RBID WA TE R
@ 23,000 CFS @ 23,000 CF S
I I
I
Side Sloughs Dist inc t Channel Indist inct Chan nel (Shoals)
Trlbuliry Mout hs Upland Sloughs @ 23,000 CFS @ 23,000 CFS
I 0 l
N
00
I Oewatered
0 9.000 CFS
r ~ 9
Clear Wate r Turb id Water Tu rbid Water Clear Water
@ 9,000 CFS @ 9,000 CFS 0 9 ,000 CFS @ 9,000 CFS
I I
l I
With Apparent Without Appa rent Side Channel Mainstem Become Distinct Remai n Ind ist inct With Appa rent Without Appa ren t
Upwelling Upwelling (Less thin 10% Side Channels @ 9,000 Up wellin g Upwelling
ot flow ) • 9,000
2 3 4 10 . 4 6 7 8
Figu re 8. Flow cha r t f o r classifying the transformation of aquatic habitat types b etween two flo ws (Categories 0-10).
The results from the habitat transformation monitoring met hodology appear i n
Appendix 3 where habitat transformation categories for each specific area
between the reference flow of 23000 cfs and all lower flow aerial photography
are listed. From the resu l ts, the number of specific areas in each habitat
transformation category was determined for eac~ evaluation flow. Tab l e 2 and
Figure 9 illust"rate how the quality and quantity of riverine habitats in the
Middle River change significantly as mainstem discharge decreases. The number
of persistent clearwater habitats (Ca t egory 1) is relatively stable throughout
the flow range. There is a substantial increase in number of side channels
that transform to sloughs as mainstem discharge decreases (Category 2) and a
corresponding decrease in number of persistent side channels (Category 4). As
can be expected, the numbers of persistent indistinct areas (Category 6) and
persistent mainstem areas (Category 10) also decrease. The number of areas
that dewater (Category 9) showed the most dramatic change, with a fivefold
increase between the highest and lowest flows. The numbers of areas described
by the remaining categories (Categories 3, 5, 7, and 8) fluctuate somewhat
over the flow range considered, but collectively account for only 10 to
20 percent of the 172 specific areas evaluated.
Table 2. Number of specific areas in each habitat transformation category b y
evaluation mainstem flow, referenced to 23000 cfs.
Evaluation Hainstem Q(cfs)
18000 16000 12500 10600 9000 7400 5100
Catesor:z: Number of s2ecific Ar eas
1 33 32 31 31 31 30 :30
2 12 15 20 25 28 31 31
3 6 6 8 8 11 10 13
4 51 47 41 36 27 25 25
5 5 6 8 11 13 11 11
6 33 32 28 2 2 18 18 15
7 3 3 3 3 3 4 5
8 3 3 5 7 8 5 4
9 6 8 13 14 20 27 30
10 20 20 15 15 13 11 8
-29 -
CATECIJIY I SPEC IFIC AAEAS CATECIJIY 2 SPEC IFIC AREAS -·-· -~~--. ~--~·~~~~--~---------------------------------------, • r--~·~~~~--~----------------------------------------,
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
..
.-·rnn.....__,'"_
--
_ .......
--
-·--·-
-----
CATECIJIY J SPECIF IC AREAS
-
-·--
.. ---
CATECOIY S SPECIFIC AREAS --·----
,.
IIIDUTI.:t SIDI au.a.l tO DUTtJICT SIDI ~
--
-
•
•
•
•
•
-------
CATECIJIT • SPECIFIC AREAS -·-· • r--~~·~RWW~~-~----------------------------------------,
•
..
•
•
•
-----,. ---
CATECIIIY 6 SPECIFIC AREAS
I --·----~ ....... •
PIUISTIIIr UIDISTIKI Mmn.l -IIDI ~ A&LU
•
•
•
•
•
--- -
---
Figure 9. Number of specific areas in each habitat transformation category at various
mainstem flows.
-30 -
CATEWIY 7 SPEC IFIC AREAS -·-.. • ~--~-~~~-~--=:---------------------------------------,
•
•
•
•
•
-----•• ---
CA TEWIY 9 SPEC IF I C AREAS -·-· • ~--~!·!~~~--~--------------------------------------~
SPU:lflC .U.U tllo\t -1'1&
•
•
•
•
..
-----•• --
F i gure 9. (cont'd)
-31 -
CAfECIJIY 8 SPEC IFIC AREAS -·-.. • ;--=:·~~~-~--~---------------------------------------,
•
•
•
•
•
•
•
•
•
•
..
UIDISTtJICT SUII Cl.-u ro SlDl SUIUCIIS WlnDIT vurna
u.wau.urc:
-----•• --
CATEQJIY 10 SPECIFIC AREAS --·--· -·-·--
PIUlftlft MlJI&tlll c:aa.IU
----•• ----·
-
-
It is interesting to note that the number of dewatered specific areas remains
relatively stable between mainstem discharges of 12500 and 10600 cfs (13 and
14, respectively), but then almost doubles with a reduction in discharge to
7400 cfs (27). An accelerated change in overall riverine habitat character
appears to occur between 10600 and 7400 cfs.
Kling~r and Trihey (1984) observed similar trends. They used wetted surface
area as an index of habitat quantity and determined that as mainstem discharge
decreases from 23000 to 9000 cfs that there was an associated decrease in
mainstem habitat (from 3737 to 2399 acres) and side channel habitat (from 1241
to 762 acres) and an increase in side slough habitat (from 53 to 156 ~cres).
The wetted surface area of upland slough habitat was relatively stable within
this flow range.
The sequence of habitat transformation categories that occurs at a specific
area as mainstem stage decreases from 23000 to 5100 cfs is the dominant index
of site specific habitat response to mainstem discharge. This sequence
provides a concise reference of habitat type and process that is useful in the
evaluation of representative groups.
4.1.2 BREACHING FLOW
In addition to habitat transformation sequence, breaching flow is useful in
describing and classifying specific areas. It is the hydrologic focal point
of gross habitat transformations and also identifies the relative position of
specific area habitats in the hydrologic spectrum between mainstem and upland
slough (Figure 10).
-32 -
BREACHING FLOW
(CFS)
35000
25000
15000
5000
HABITAT TYPE
UPLAND SLOUGH
SIDE SLOUGH
SIDE CHANNEL
MAINSTEM
Figure 10 . General relationship between breaching flow and habitat type
in the Talkeetna to Devil Canyon segment of the Susitna River.
-33 -
Breaching flows were determined with considerable confidence within the f l ow
range for which aerial photography was available (5100 to 26900 cfs). Field
observations were used to verify and refine approximations that were based on
aerial photo interpretation. Above 26900 cfs, ADF&G field observations were
the primary source of breaching flow estimates. It was generally not possible
to refine breaching flow estimates for specific areas breached significa~tly
below 5100 cfs because of the lack of available information. Specific areas
that appeared to be "barely breached" in the 5100 cfs photography were
assigned a breaching flow just under 5100 cfs. Breaching flows for each
specific area are listed in Appendix 4.
4.1.3 CROSS SECTIONAL GEOMETRY OF SIDE CHANNEL HEAD BERMS
Plots of wetted top width at the head berm versus mainstem discharge were
developed for 46 specific area channels that had low breaching flows and
readily identifiable head berms. These were classified by curve &lope into
four categories: (1) steep; (2) moderate; (3) flat; and (4) irregular
(Figure 11).
follows:
The interpretation of each category of curve slope is as
(1) steep slopes are indicative of broad channel sections with
relatively gentle-sloped sides at the head berm;
(2) moderate slopes are indicative of channels with a cross-sectional
geometry at the head berm that is flat on one side and steep on the
other;
(3) flat slopes are indicative of channels with relatively narrow and
incised cross-sectional geometry at the head berm; and
-34 -
........ , •
•
•
•
•
......... •
•
•
•
•
Figure 11.
1n2 R 129.3 L .... ., .. •
•
•
•
•
--... -----
-
.. _ .... , .. ~ ......
STEEP MODERATE
127.0 M 128.5 R ........ •
•
•
•
•
---,.. --... ..... ~. .. c.-I CPI.I
FLAT IRREGULAR
Representative wetted top width versus discharge plats for each
category of curve slope .
-3:> -
-,..
-,..
(4) irregular or stepped curves are indicative of channels with
irregular cross-sectional geometry at the head berm.
The significance of the cross sectional geometry at the head berm of channels
in classifying aquatic habitat can be summarized best by examining the
hypothetical flow apportionment to two parallel channels with comparable
breaching flows, but different cross-sectional geometry (Figure 12). Note
that for the same increase in stage at the head berm, a channel that is broad
with gentle-sloping sides will receive more flow than a channel with a
relatively narrow cross sectional geometry. The wetted surface area of the
broad channel will likewise be greater than that for the narrow channel, and
will increase at a faster rate per incremental increase in stage. In short,
the broad channel will provide more, but less stable, aquatic habitat per unit
of mainstem stage than will the narrow channel. In a hydrologic sense , the
broad channel would be termed responsive or perhaps, "flashy." A listing of
the curve slope c lasses for the 46 specific areas evaluated in the Middle
River appears in Table 3.
The study of the cross sectional geometry at side channel head berms was of
lesser value for the characterization of the hydrologi c component of specific
area habitats than either habitat transformation c ategories or breaching
flows. Three factorR limited the value of head berm cross sectional geometry
to this study: (1) only specific areas that were distinct side channels could
be studied ; (2 ) only specific areas that had discernible he~d berms could be
studied; and (3) only specific areas with relatively low breaching flows could
be studied.
-36 -
VI z:
0
1-< > ... _. ....
FLAT
TOP WIDTH (FT o)
LEGEND
\.Jater surface
1-u ...
VI
VI
VI
0 a: u
TOP WIDTH (FT 0)
Figure 12. Cross sectional geometry at the head berm of two channels having the same br~aching flow. No t e
how differenc e s in cross sectional geometry affects the rate of wett ed surfac e area developme nt
for a comparabl e .lnc r ease in mainstem stage,
Table 3. Curve slope classes of plots of wetted top width versus discharge
from measurements made at channel head berms at 46 specific areas in
the Talkeetna to Devil Canyon segment of the Susitna River.
Specific
Area
100.6L
100. 7R
101.2R
101.5.1..
102.6L
105.7R
106.3R
108. 7L
108.9L
109.4H
110.8H
11l.OR
111. SR
112.6L
ll4.0R
115.0R
116.8R
117.7L
ll7. 8L
119. 2R
ll9. 6L
121.1L
121. 7R
Curve
Slope
Class
3
2
2
2
4
4
4
3
2
3
3
3
3
1
3
1
4
3
2
2
3
2
3
Specific
Area
123.0L
124.1L
125.2R
125.6L
127.0M
127.1H
127.4L
128.SR
129.3L
130. 2R
130.2L
131.7L
132.6L
134. 9R
13S.OL
136.0L
137.2R
138.0L
138.8R
139.4L
139.6L
l44.2L
l45.3R
Curve slope classes : 1 • steep, 2 • moderate, 3 • flat, 4 • irregular
4.1.4 CROSS SECTIONAL GEOMETRY Ol' HAINSTEH
Curve
Slope
Class
3
3
3
2
3
4
2
4
2
1
3
4
3
3
3
3
l
1
1
4
3
3
2
The increase in mainstem stage due to an increase in mainstem· discharge varies
between mainstem subsegments of the Middle River (Table 4). The
responsiveness of mainstem stage to discharge in a subsegment has a direct
influence on the hydrologic regimen of adjacent side channels. In subsegments
where mainstem stage is relatively responsive to changing discharge, the
volume of flow entering adjacent side channels will be relatively unstable.
The opposit~ is true in subsegments where mainstem stage resp onds less
-38 -
dynamically to changing discharge. From the information in Table 4 . it would
be expected that side channel habitats within the continuous subsegment from
river miles 131 to 137 would have less stable flow regimes than other c hannels
in the Middle River. The use of mainstem stage dynamics as an index to
characterize aquatic habitat is most useful when considered in conjunction
with site specific indices of flow frequency and magnitude (i.e •• breaching
flow and cross sectional geometry of the head berm). However. the limitations
of the data set describing cross sectional geometry of head berms precludes
the use of regional mainstem geometry as a good index of site character for
the specific areas delineated i n the Middle River.
Characteristic mainstem stage fluctuations may prove useful in subsequent
analyses; especially in the interpretation of weighted usable area curves.
For example. a steep and laterally compressed weighted usable area curve could
be explained by the relatively large response of mainstem stage to discharge
at a mainstem subsegment.
Table 4. Stage i ncrease at selected cross sections in the Ta l keetna to De v il
Canyon segment of the Susitna River as mainstem discharge i ncreases
from 9700 to 23400 cfs.
Cross Section River Stage Increase
No. Mile (Ft.)
7 101.5 1.9
11 106.7 2 .6
25 121.6 2.2
29 126.1 2.0
36 131.2 3.5
44 136.4 3.3
49 138.2 2.8
5 4 140.8 2 .7
55 141.5 2.4
Source: R&M Consultants 1982
-39 -
4.1 .5 EVALUATION OF UPWELLING
Table 5 lists the specific areas t.hat the investigators determined possess
upwelling. Of 59 specific a~eas that had open leads in the winter
photography, 40 (68%) were observed to have chum salmon spawning activity.
There was also a strong correlation between the presence of chum salmon
spawners and those specific areas where upwelling was observed in the field
but did not necessarily have open leads in the winter photography. Of these
85 sites, 48 (56%) were observed to have chum salmon spawning activity.
More indicative of the importance of upwelling to chum salmon spawners is the
percentage of specific areas where spawning activity was observed that also
had upwelling. Of the 53 specific areas where spawning activity was obse~ed,
48 (91%) were observed to have upwelling. ADF&G maps of chum salmon spawning
areas were thus used to corroborate upwelling. A summary of fish observations
appears as Appendix S.
Although there is considerable confidence that specific areas identified as
possessing winter upwelling actually do, it is also probable that other
riverine areas do as well. It is possible that the thermal quality of
upwelling that occurs in relatively deep or swift and turbulent currents will
become sufficiently diffused by mixing to preclude the formation of a thermal
lead in the winter ice cover.
-40 -
Table S. Suaaary of the specific areas that possess upwelling in the
Talkeetna to Devil Canyon segment of the Susitna River.
s2ecific Areas with U2wellin1
River Open Spawning* River Open Spawning*
Mile Leads Activiti Mile Leads Activiti
100.60R X X 129.40R X X
100.60L 130.20R X X
101. 20R X X 130. 20L X
101.40L X X 131. 30L X X
101.60L X X 131. 70L X
101.71L X l31.80L X
101.80L X X 132.60L
102.20L X X 132. 80R X X
107.60L 133.70R X X
l10.40L X 133.80L X
111.60R 133.90R X X
112. SOL X 133.90L X X
112.60L 134.00L X
113. 70R X X 134.90R X
11S.OOR X X 13S.10R
11S. 60R X X 13S. 30L
116.30R 13S. 60R X X
117 .SOL X 13S. 70R X
117. 90L X X 136.30R X X
118.00L 136. 90R X
118.60M l37.20R X X
118. 91L X X 137.SOR X
119.11L X X 137 .SOL
119. 30L X X 137.80L X
119.70L X l37.90L X
l20.00R X X 138. OOL X
121.10L X 138. 71L
122.40R X X l39.00L X X
l22.SOR X X 139.01L X
123.20R 139. SOR X
123.60R X X 139. 70R X
124.00M X 139.90R X X
12S.10R X l40.20R X X
12S.90R X X 140.60R X
126.00R X X 141.40R X X
126.30R X X 141. 60R X X
127.00L 142.10R X X
l2'1.20M X 143.00L X X
127.40L 143.40L X
128.SOR X l44.20L
128.70R X X 144.40L X X
128.80R X X 14S.60R
129.30L
*Spawning activity observed as indicated by the presence of redds or spawning
behavior.
-41 -
4.2 HYDRAULIC COMPONENT
Analysis of the hydraulic component of specific area habitats was focused on
estimated or measured mean reach velocity during breached conditions,
substrate size, and channel morphology. Of these three variables, mean reach
velocity was the best and most direct index of channel hydraulics for use in
the characterization of habitat.
4.2.1 MEAN REACH VELOCITY
The side channels of the Middle River constitute a complex flow delivery
system with individual side channels beginning to flow at various mainstem
discharges according to their breaching flows. A comparison of mean reach
velocities between side channels for any given mainstem stage would yield a
range of values depending on whether the channels were nonbre:l ched, barely
breached, or flowing vigorously. Mean reach velocity is thus a
stage-dependent variable whose use as a comparative index of side channel
hydraulics is complicated by a dependence on bre aching flow.
Mean reach v elocities were measured or estimated in this study at mainstem
discharges ranging from approximately 8000 to 11000 cfs. In a few cases.
estimate s were made at 18000 cfs. Because of the relatively low flows that
were coincident with the field trips, most channels where velocities were
measured had relatively low breaching flows. This reduced the need to
conside~ the variability of breaching flows between channels in the
interpretation of mean reach velocity data. Although it is possible to
normalize mean reach velocity measurements at different side channels on the
basis of breaching flow, it was not considered necessary in this study. Mean
reach velocities are presented in Tables 8-17.
-42 -
Two factors restricted the value of mean reach velocities for u se in the
comparative evaluation of specific area hydraulics: ( 1) an incomp l ete data
set; and (2) the stage dependence of velocity. It was not possible to obtain
mean reach velocities during breached conditions for each specific area
because channels were sometimes nonbreached coincident with the habitat
reconnaissance field work. Most channels contained insufficient flow during
nonbreached conditions to be useful in the characterization of channel
hydraulics. Mean reach velocities were obtained during breached conditions
for 61 of the 172 specific areas delineated in the Middle River.
The velocity data collected was useful in describing the hydraulic
characteristics of each habitat transformation category. The following
generalizations are provided to develop a qualitative appreciation of the
trends depicted in Figure 9.
Category 0 -Tributary mouth habitat. These habitats exist as clear water
plumes at the confluence of tributaries to the Middle River . This
category has not been directly addressed within the extrapolation
methodology because of the comparatively small amount of surface area
associated with this habitat type.
Category 1 -Upland slough and side slough habitats that do not transform
within the flow range of interest. These areas offer low velocities,
frequently near-zero, with the greatest hydraulic disparity being depth.
Category 2 -Side slough habitats that have transformed from side channel
habitats and which possess winter upwelling. These areas, nonbreached by
-43 ·-
definition, are typified as a series of clearwater pools connected by
short shallow riffles. Riffle velocities are frequently less than l fps
and 0.5 feet or less in depth. Pool velocities are near zero and depths
are generally less than 3 feet.
Category 3 -Side slough .habitats that have transformed f r om side channel
habitats. Distinguished from Category 2 areas only by the lack of an
upwe~g groundwater source that persists throughout winter. The
hydx·aulic characterization remains the same as for Category 2.
Categor~ 4 -Side channel habitat that persists as side channel habitat
through the flow range of interest. These areas, breached by definition,
display greater hydraulic diversity than the previous categories.
Velocities range from approximately 2-5 fps (10000 cfs mainstem) between
specific areas.
Category 5 Side channel habitat that has transformed from indistinct
channels (Category 6). Distinguished from Category 4 areas primarily by
the presence of one gravel-bar bank which becomes inundated at high
mainstem discharges causing the channel to appear less visible
(indistinct) in the aerial photography. These channels typically have
higher velocities, often greater than 5 fps (10000 cfs mainstem), than
Cat~gory 4 channels.
Category 6 -Indistinct areas that remain indistinct through the flow range of
interest. This category includes those riverine areas termed shoals. By
definition, they are breached, shallow water areas, typically marginal to
-44 -
a mainstem channel. Depths are generally under 4 feet and velocities
reduced compared to mean mainstem velocities as a result of c hannel edge
effects.
Category 7 -Side slough habitats that have transformed from turbid indistinct
channels and which possess winter upwelling. These areas are
distinguished from Category 2 areas primarily by their origin from
indistinct rather than distinct channels. The hydraulic characterization
remains the same as for Category 2.
Category 8 -Side slough habitats that have transformed from turbid indistinct
areas. These areas are distinguished from Category 3 areas primarily by
their origin from indistinct rather than distinct channels. The
hydraulic characterization remains the same as for Category 3.
Category 9 -Specific areas that become dewatered. This is a terminal
category that requires no hydraulic characterization. These areas may
contain isolated pools that, by definition, have no habitat value.
Category 10 -Mainstem habitats that do not transform within the flow range of
interest. These channels are typically deeper and s~tfter than any other
habitat category. Mean velocities are frequently 5 fps (10000 cfs
mainstem) or gr~ater.
4.2.2 SUBSTRATE SIZE
In the evaluation of substrate size, dominant substrate codes were used.
Frequently more than one code was selected because of the evenly balanced
-45 -
mixture of fine and coarse substrate size classes present at man y spec ific
areas. 'sands were distributed throughout the Middle River segment, and were
considered to be less indicative of specific area hydraulics. For this
reason, when more than one dominant substrate size code was selected, the
coarser size class was used as the index of channel hydraulics.
A shortcoming of using codes to characterize substrate size is the subjective
nature of the determination. The use of two-person crews in a consensus
arrangement likely eliminated much of the potential for individual bias.
Dominant substrate sizes are presented in Tables 8-17.
Substrate size was a less valuable index of channel hydraulics than mean reach
velocity. Although it was evident dur ing the habitat reconnaissance work that
mainstem channels had recognizably coarser substrate and swifter velocities
than other habitats, it was more difficult to generalize substrate size and
the hydraulic characteristics of side channels. Substrate size in side
channels is less directly correlated with channel slope and more strongly
influenced by factors relating to sediment supply. These factors are likely
channel head berm geometry, channel orientation to the mainstem, and
influences from localized sediment sources.
4.2.3 CHANNEL MORPHOLOGY
Channel morphology was the most indirect index of specific area hydraulics
used to characterize habitat. During the course of the habitat reconnaissance
field work, considerable evidence of repetitive form was observed throughout
the Hiddle River. Sometimes a distinct plan form was recognized from the air
in tnnsit to a specific area. Other times a distinctive riffle/pool pattern
-46 -
was recognized while on the g round. Similarities between specif i c a r eas were
recordet! on the habitat inventory data form for future considera tion in the
development of representative groups. Careful inspection o f aerial
photography also revealed similarities in plan form between individual side
channels.
R&M Consultants divided the Middle River into six discrete continuous
subsegments based on characteristic mainstem channel pattern (Table 6).
Dividing the mainstem in this manner provides the basis for evaluating long
term trends in main ch, mnel morphology. More applicable to the study of
juvenile salmon habitat, which is concentrated in the peripheral areas o f. the
river, is the identification of side ch.annel complexes. Complexes are systems
of adjacent, often interconnected, side c hannels which convey mainstem ~ater.
Major side channel complexes of the Middle River c.re listed in Table 7 and are
easily discernible in the aerial photography in Appendix 1.
Channels within a CCJmplex are sometimes hydraulically, hydrologically, and
morphologically similar since they are influenced by the same mainstem
conditions, such as slope, stage response to discharge, and sediment load.
However, more than one habitat type is generally represented in a complex.
Furthermore, each habitat type is sporadically represented in different side
channel complexes throughout the Middle River .
-47 -
Table 6. Definition of subsegments within the Talkeetna to Devil Canyon
segment of the Susitna River.
River Mile
RH 149 to 144
RH 144 to 139
RH 139 to 129.5
RH 129.5 to 119
RH 119 to 104
RH 104 to 95
Average
Slope
0.00195
0.00260
0.00210
0.00173
0.00153
0.00147
Source: R&H Consultants 1982.
Description
Single channel confined by valley
walls . Frequent bedrock control
points.
Split channel confined by valley walls
and terraces.
Split channel confined occasionally by
terraces and valley walls. Main
channels, side channels sloughs occupy
valley bottom.
Split channel with occasional tendency
to braid. Main channel frequently
flows against west valley wall.
Subchannels and sloughs occupy east
flood plain.
Single channel frequently incised and
occasional islands.
Transition from split channel to
braided. Occasionally bounded by
terraces. Braided through the
confluence with Chulitna and Talkeetna
Rivers.
Table 7. Major side channel complexes of the Talkeetna to Devil Canyon
segment of the Susitna River.
Reference Name
Whiskers Creek
Bushrod Slough
Oxbow II
Slough 8B
Skull Creek
Fourth of July
Slough 21
-48 -
Location (RH)
100-102
117-118
119-120
121-123
125-126
131-132
141-142
A statistical app r oach was taken to study the simHarities between side
channel areas in the Middle River based on plan form. Through a cluster
analysis of several side channel variables, including length, width, length to
width ratio, channel sinuosity, and the number of bends, six distinct cluster
groupings were identified. The findings corroborated subjective evaluations
of morphologic similarities between side channels.
A discriminant function multivariate analysis was performed using the six
cluster groupings to determine the relative importance of variables in
defining morphologic groups . The length to width ratio was the most important
variable, and channel width was second, followed by channel length. A
limitation of the multivariate analysis was that it could be applied only for
distinct side channels where it was possible to evaluatP. each of the
previously mentioned variables. This limited the analysis to 70 cases
(specific areas).
4.3 STRUCTURAL COMPONENT
Characterization of the structural component of aquatic habitats was focused
primarily on six variables: (1) dominant cover code; (2) percent cover;
(3) channel geometry; (4) dominant substrate size; (5) substrate embeddedness;
and (6) streambank vegetation. Although the field evaluation of each of these
variables relied on subjective judgements of field personnel, it is believed
that the consensus arrangement provided by two-person crews limited individual
bias. On-site photographs provided a vehicle for review and verification or
adjustment of field evaluations.
-49 -
The integration of the above six variables into a c omp o s i te index of
structural habitat quality is represented by 3 tructural habitat ind ices (SHI ).
In the formulation of structural habitat indices, it is necessary to rank and
weigh the relative importance of each variable to juvenile salmonid habitat
quality. There is little information in the literature pertaining to ranking
or weighting schemes of habitat variables. Hynes (1970) notes that it is
generally recognized that temperature, water quality, water depth and
velocity, cover or shelter, and streambed material are the most important
physical variables affecting the amount or quality of riverine fish habitat.
Two of these variables, cover and streambed material, were directly included
in t he formulation of structural habitat indices.
The identification of the appropriate variables for describing structural
habitat was considerably easier than the assignment of weighting factors of
relative importance. The criterion that was used in the establishment of
weighting facto~s was that resulting structural habitat indices must
corroborate subjective habitat quality evaluations recorded on habitat
inventory field forms. This was satisfied by the following weighting scheme
for the respective variable/variable combinations: (l) dominant cover/percent
cover (0.45); (2) channel morphology (0.30); (3) dominant substrate
size/substrate embeddedness (0.20); and (4) streamside vegetation (0 .05).
Structural habitat indices for each specific area appear in Tables 8-17.
In viewing the range of SHI values within representative groups. two
conclusions are apparent: (1) most specific areas have comparable SHI values;
and (2) some specific areas are rated two or three times as valuable to
-50 -
juvenile salmonids for rearing as others. Th e f i rst co nclu s i on is explai ned
as the result of similar river process es occu rring within each rep res e nt a t i v e
group. The second conclusion is reasonable and reflects t he imp o rtance of
structure to overall juvenile salmonid habitat quality . Projects that ut ilize
instream structures hav e demonstrated that cover f or f ish can mea n t he
difference between fish util izing an area or not (Claire 1978).
Although the basis for the SHis was lar gely found e d on subject i ve
determinations, it is believed that the conse nsus arrangement used in
subjective evaluations and the applicat i on of a common methodology
significantly curtails individual b ias and justifies their use as a relative
index of structural habitat quality.
4.4 DEVELOPMENT OF REPRESENTATIVE GROUPS
Representative groups are composed of specific areas that are hydrologically,
hydraulically, and morphologically similar . Variables that were considered in
the development of
transformation category
representative groups
sequence, breaching
are
flow,
as follows: habitat
mean reach velocity,
substrate size, and channel length to width ratio. Field notes provided core
groupings of specific areas that were observed to be similar. Field
experience coupled with professional judgement provided the balance of the
matrix needed to discern representative groups.
Although information pertaining to each of the components of aquatic habitat
character was considered in the development of representative groups,
frequently one or two components dominated the distinction of a group. Of the
ten representati ve groups developed, hydraulic and morphologic variables
-51 -
each provided the primary distinction in three groups, and hydrologic
variables provided the primary distinction in four.
representative group appear in Tables 8-17.
-52 -
Descriptions of each
Table 8. Representative Group I
Description: Habitat character is dominated by high breaching flow. This group
includes all upland sloughs and Slough 11 (RM 135. 6R). Specific area hy draulics art!
characterized by pooled clear water with velocities frequently near-zero 4nd depth i
greater than 1 ft. Pooled areas are commonly connected by short riffles wher~
velocities are less than l fps and depths are less than 0.5 ft.
Specific
Area
100.6R
102.2L
105.2R
107.6L
108.3L
112.5L
119.4L
l20.0R
121. 9R
123.1R
123.3R
127.2M
129.4R
133. 9R
133.9L
l34.0L
135.6R
136. 9R
137 .5L
139.0L
139.9R
Breaching
Flow
(cfs)
us
us
us
us
us
us
us
us
us
us
us
us
us
us
us
us
42000
us
us
us
us
Habitat
Transformation
Category
Sequence
1
1
l
l
1
1
1-9
1
1
1
1
1
1
1
1
1
1
1
l
1
1
1 Mean
Reach
Velocity
(fps)
0+
0+
1. 0
0+
1. 0
0
0
0+
<1.0
0+
0
0+
0+
<1,0
<0.5
0+
0+
0+
<0.5
0
0+
Dominant
Substrate
Code
9
l
l
2
1
l
1
1
9
1
2
2
l
7
9
1
6
2
1
2
1
1Mean reach velocities for nonbreached conditions
US • Upland Slough
MSS • Mainstem Shoal
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• Data Not Available
-53 -
Channel
Length
to Width
Ratio
Structural
Habitat
Index
0.6')
0.83
0.64
0.44
0.70
0.68
0.45
0.50
0.83
0.45
0.67
0.58
0.44
0.50
0.67
0.99
0.54
0.69
0.60
0.45
0.74
RJIAB
RJJ!AB
Table 9. Representative Group II
Description: Habitat character is dominated by relatively high breaching flows and
the presence of upwelling groundwater sources that persist throughout winter . This
group includes the spe c ific areas that are commonly called sloughs. These specific
areas typically have relatively large channel length to width ratios.
Breaching
Spec ific Flow
Area (cfs)
101.4L 22 000
101. 8L n ooo
113. 7R 24000
115. 6R 22000
117. 9L 19500
122.4R 25000
122.5R 20000
125.1R 20000
125.9R 26000
126. OR 33000
126.3R 26000
131.8L 26900
137.5R 22000
137.8L 20000
137.9L 21000
140.2R 26500
142. 1R 23000
14 4.4L 21000
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
2
2
1
4-2
2
1
2
2
1
1
4-2
1
2
2
2
1
1
2
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• Data Not Available
-54 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
10 38.4 0.54 RJHAB
10 77.8 0.60
6 100.0 0.51 RJHAB
9 21.2 0.54
9 29.3 0.62
1 23.1 0.29
8 104.5 0.51
3 25.5 0.48
12 74.7 0.56
9 71.8 0.51 IFG
9 39.6 0.59
8 0.45
12 0.44 DIM
11 15.0 0.64
11 76.0 0.50
11 73.3 0.50
11 0.65
13 91.5 0 .60 RJHAB
Table 10. Representative Group III
Description: Habitat character is dominated by intermediate breaching flows and
relatively broad channel sections. This group includes side channels which become
nonbreached at intermediate mainstem discharge levels and transform into slough
habitat at lower discharges. Breaching flows are typically lower than for Group II,
upwelling is present, and the length to width ratios of the channels are generally
less than ratios for Group II.
Breaching
Specific Flow
Area (cfs)
100.4R 12500
101. 2R 9200
101. 6L 14000
101. 7L 9600
110.4L 12000
115.0R 12000
119. 3L 16000
128.5R 10400
128.7R 15000
128.8R 16000
130.2R 12000
130.2L 8200
132.6L 10500
133.7R 11500
137.2R 10400
141.4R 11500
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
4-2
4-2
4-2
4-3
4-2
4-2
4-2
4-2
4-2
4-2
4-2
4-3
4-3
4-2 3.5
4-2 2.5
4-2
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• No Data Available
-55 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
8 22.5 0.51
8 8.1 0.56 IFG
10 14.8 0.61
10 10 .5 0.46
11 37.6 0.67
10 15.3 0.55 DIM
10 25.8 0.56
8 0.48
6 20.8 0.49
3 39.1 0.34 IFG
9 15.9 0.64 DIM
11 33.5 0.60
10 65.2 0.49 IFG/
RJHAB
10 71.4 0.44
12 8.6 0.49
12 0.56 IFG
Table 11. Representative Group IV
Description: Habitat character is dominated by low breaching flows and intermediate
mean reach velocities. This group includes the specific areas that are commonly
called side channels . These specific areas possess mean reach velocities ranging from
2-5 fps at a mainstem discharge of approximately 10000 cfs.
Breaching
Specific Flow
Area (cfs)
100.7R <5100
10l.5L <5100
108. 7L <5100
110.8H <5100
111. 5R <5100
112. 6L <5100
114.0R <5100
116.8R <5100
119. 5L 5000
119.6L <5100
121. 7R <5100
124.1L <5100
125.2R <5100
127.0L <5100
127.4L <5100
129.5R <5100
131. 7L 5000
134.9R <5100
136.0L <5100
139.4L <5100
139.6L <5100
140.4R <5100
144.0R <5100
145.3R <5100
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
10-4 3.8
10-4 3.0
10-4 3.0
4 3.5
10-4 2.5
4 3.0
4 3.0
10-4 4.5
4 2.5
4 3.0
10-4 4.0
10-4 3.5
4 4.5
4 2.5
10-4 4.0
6-5 3.0
4 2.6
4 4.0
4 2.0
4 2.0
10-4 3.2
6 3.0
10-4 >5.0
10-4 4.5
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• No Data Available
-56 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Hodel
8 14.5 0.49
12 12.7 0.45 IFG
11 6.9 0.53
6 5.9 0.48
9 13.8 0.48
10 10.0 0.60 IFG
9 0.43
9 10.6 0.48
8 20.9 0.54
10 54.6 0.53
8 24.7 0.48
11 17.0 0.46
10 37.8 0.61 DIM
7 10.1 0.65
9 36.4 0.46
8 13.5 0.56
10 48.6 0.47 IFG
8 22.3 0.56 IFG
5 24.0 0.55 IFG
8 3.6 0.61
13 14.9 0.51
10 7.7 0.48
11 15.1 0.53
12 11.8 0.53
Table 12. Representative Group V
Description: Habitat character is dominated by channel morphology. This group
includes shoal areas which transform to slough or clearwater habitats as mainstem
discharge decreases.
Breaching
Specific Flow
Area (cfs)
101. 71L MSS
113.1R 26000
117 .OM 15500
118. 91L MSS
121.8R 22000
123.2R 22000
124.0M 20000
132.8R 19500
139.01L MSS
139.7R 22000
141.6R 21000
143.0L 7000
146.6L 26500
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
7-9
1
6-7-9
6
3
8-9
7
7
6
2
7
6-7
1-9
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Mod~l
--• No Data Available
-57 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
9 0.48 DIM
6 0.43
3 0.31
9 0.48 DIM
2 20.9 0.27
3 0.26
6 0.51
8 36.0 0.57
6 0.37 DIM
3 0.51
3 0.56 IFG
5 0.31
12 0.48
Table 13. Representative Group VI
Description: Habitat character is dominated by channel morphology. This group
includes overflow channels that parallel the adjacent mainstem, usually separated by a
sparsely vegetated gravel bar. These specific areas may or may not possess an
upwelling groundwater source.
Breaching
Specific Flow
Area (cfs)
100.61 9200
102.61 6500
106.3R 4800
107.11 9600
117.81 8000
117. 9R 7300
118.01 22000
119. 7L 23000
123.6R 25500
133.81 17500
135.31 18500
135.7R 27500
136.3R 13000
138.01 8000
138.8R 6000
139.5R 8900
140.6R 12000
142.0R 10500
143.41 30000
US a Upland Slough
HSS • Hainstem Shoal
Habitat He an
Transformation Reach
Category Velocity
Sequence (fps)
4-3
4-3 2.0
4 2.5
4-3-9
4-2
4-3 2.0
3
2
1
4-2
3
1
4-2
4-2
6-5-9 3.0
6-5-7 2.5
6-5-8-9
5-8
1
IFG • Instream Flow Group Habitat Hodel
DIH • Direct Input Hodel developed by EWT&A
RJHAB • ADF&G Habitat Hodel
--• No Data Available
-58 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
11 12.0 0.42
12 14.2 0.69
11 17.4 0.53
12 0.69
9 19.2 0.48
12 24.7 0.49
9 12.8 0.39
9 0.51
2 0.43
9 24.0 0.49 IFG
12 19.1 0.30
3 26.0 O.J2
11 14.4 0.54 IFG
11 0.53
9 15.0 0.31
12 0.31
10 0.61
12 0.53
13 60.0 0.55
Table 14. Representative Group VII
Description: Habitat character is dominated by a characteristic riffle /pool sequence.
The Little Rock IFG modeling site (RM 119.2R) is typical with a riffle j ust downstream
of the side channel head that flows into a large backwater pool near the mouth.
Breaching
Specific Flow
Area (cfs)
114.1R <5100
119. 2R 10000
121.1L 7400
123.0L <5100
125.6L <5100
125.7R 22000
127.5M <5100
131.3L 8000
US • Upland Slough
M~S • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
5 2 .5
4-3 3.6
4-3 3.0
4 2.0
6-5 3.5
4
6-5 3.5
4-2
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• No Data Available
-59 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
8 22.8 0.31 DIM
10 15.1 0.41 IFG
6 41.2 0.43
7 17.4 0.39
12 9.5 0.52
9 10.7 0.62
6 24.2 0.31
7 18.2 0.31 DIM
Table 15. Representative Group VIII
Description : Habitat character is dominated by the tendency of the s e cha nne l s t o
dewater at a relatively high mainstem discharge. Channe l s in t h is group are
frequently oriented with a 30°+ angle to the mainstem flowline at their heads.
Breaching
Specific Flow
Area (cfs)
101. 3H 9200
102.0L 10000
104.3H 16500
109.5H 16000
112.4L 22000
117. 1H 15500
117. 2H 20000
118.6H 14000
119.8L 15500
120.0L 12500
12l.SR 19500
121.6R 15500
124.8R 19500
125.6R 22000
128.4R 9000
132.51 14500
13S.OR 21500
135.1R 20000
13S.SR 21000
144.0H 22000
145.6R 22000
US • Upland Slough
HSS • Hainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
4-9
4-9
4-3-9
4-9
9
4-3
3-9
5-8
4-9
4-3-9
3-9
4-3-9
8-9
9
6-5-9
4-9
9
3
9
9
9
IFG • Instream Flow Group Habitat Hodel
DIM • Direct Input Hodel developed by EWT&A
RJHAB • ADFIG Habitat Hodel
--• No Data Available
-60-
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
11 9.3 0.57
5 2.4 0 .43
9 4.3 0.48
9 8.7 0.49
11 18.4 0.27
3 16.0 0.32
3 9.8 0.32
3 0.26
9 7.8 0.51
10 20.3 0.32
6 0.32
9 0.60
2 3.9 0.46
8 12.7 0.54
8 0.56
11 10.0 0.57
6 11.2 0.44
6 18.9 0.44
1 0.32
12 9.0 0 .31
8 56.3 0.6 2
Table 16. Representative Group IX
Description: Habitat character is dominated by low breaching flows and relatively
swift velocities. This group includes specific areas that were categorized as
mains tem at 5100 cfs. as well as side channels (Category 5) and indistinct side
channels (Category 6) with mean reach velocities greater than 5 fps at 10000 cfs
mainstem.
Breaching
Specific Flow
Area (cfs)
104.0R <5100
105.7R <5100
108.9L <5100
109.4R <5100
11l.OR <5100
113. 8R <5100
117.7L <5100
127.1H <5100
128.3R <5100
129.3L <5100
129.8R <5100
131.2R <5100
135.0L <5100
139.2R <5100
141. 2R <5100
141.3R <5100
142.8R <5100
144.2L <5100
147.1L <5100
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
6 5.5
10 3.0
10 5.0
10 >4.0
10 3.5
6 6.0
6-5 5.5
6-5 5.0
6 >5.0
10-5 >6.0
10 >4.0
5 >5.0
10 4.5
6
6-5 >5.0
5 >5.0
6 >5.0
10 3.5
10 5.0
IFG • Instream Flow Group Habitat Hodel
DIM • Direct Input Hodel developed by ~WT&A
RJHAB • ADF&G Habitat Model
--• No Data Available
-61 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Hodel
8 9.4 0.48
11 8.6 0.53
11 9.0 0.58
12 18.2 0.45
6 12.3 0.35
12 7.2 0.53
8 8.5 0.41
10 13.9 0.53 --
12 0.63
12 12.2 0.62
12 9.7 0.56
8 13.6 0.59
12 6.1 0.48
10 10.7 0.61
13 0.69
12 0.69
12 0.56
12 21.0 0.53
12 10.8 0.57 IFG
Table 17. Representative Group X
Description: Habitat character is dominated by channel morphology. This group
includes large mainstem shoals, and mainstem margin areas that had open leads in the
March 1983 photography.
Breaching
Specific Flow
Area (cfs)
105.81L MSS
109.3M MSS
111.6R 11500
113.6R 10500
113. 9R 7000
119.11L MSS
121.1R MSS
133.81R MSS
138 . 71L MSS
139.3L MSS
139.41L MSS
142.8L MSS
148.2R MSS
US • Upland Slough
MSS • Mainstem Shoal
Habitat Mean
Transformation Reach
Category Velocity
Sequence (fps)
6
6-9
6-8-9
6-8
6
6 2.0
6-5 3.5
6 2 .0
6 3.0
6
6 3.5
6 1.5
6-9
IFG • Instream Flow Group Habitat Model
DIM • Direct Input Model developed by EWT&A
RJHAB • ADF&G Habitat Model
--• No Data Available
-62 -
Channel
Dominant Length Structural
Substrate to Width Habitat
Code Ratio Index Model
12 0.57 DIM
8 0.48
10 0.49
8 0.55
8 0.48
8 0.41 DIM
10 4.8 0.47
12 0.48 DIM
12 0.57 DIM
10 0.56
11 0.41 DIM
9 0.36
12 C.48
5. CONCLUSIONS
Aquatic habitat characterizations were developed for specific areas of the
Talkeetna to Devil Canyon segment of the Susitna River using aerial photo
interpretation and habitat inventory procedures. An accelerated change in
overall riverine habitat character occurs in the flow interval from 10600 to
7400 cfs (USGS Gold Creek) as indicated by the number of specific areas that
dewater in the aerial photography as mainstem discnarge decreases.
Discontinuous subsegments composed of specific areas of the Middle River that
are hydrologically, hydraulically, and morphologically similar were
discriminated for use ~.n the extrapolation of habitat quality and usability
indices from modeled areas to nonmodeled areas. Ten of these composite
subsegments, termed "representative groups," were developed (Tables 8-17).
Differences in habitat quality within representative groups may occur because
of differences in structural habitat quality between specific areas.
Structural habitat indices were formulated from six structural habitat
variables to a~count for these differences in the extrapolation methodology.
-63 -
LEAVE BLANK PAGE
-64 -
LITERATURE C I~ED
Arctic Environmental Information and Data Center. 1984. Ge umorph i c c hange in
the Devil Canyon to Talkeetna reach o f the Sus itna Riv e r since 1949 .
Arctic Environmental Information and Data Center , Univ ersity of Al aska ,
Fairbanks. Preliminary report for Alaska Power Au thority, Su s i tna
Hydroelectric Project, Anchorage, AK ~ 1 vol .
Chow, V.T. 1959. Open-channel hydraulics. New York , Mc Graw-Hill Book
Company, Inc.
Claire, E. 1978. Rock work. Pp. 2-3. In Proceedings of fis h ha bitat
improvement workshop. Ochoco Ranger Station . September 26-27, 197 8 .
Oregon Department of Fish and Wildlife. 17 pp .
E. Woody Trihey and Associates and Woodward-Clyde Consultants . 1985 .
Instream flow relationships report. Volume No. 1. Draft report f o r
Alaska Power Authority, Susitna Hydroelectric Project, Anchorage, AK .
Estes, C.C., and D.S. Vincent-Lang, eds. 1984. Report No. 3. Aquatic
habitat and instream flow investigations (May-October 1983). Chapter 7 :
An evaluation of chum and sockeye salmon spawning habitat in sloughs and
side channels of the middle Susitna River. Susitna Hydro Aq u atic
Studies, Alaska Dept. of Fish and Game. Report for Alaska Power
Authority, Anchorage, AK. Document 1936. 1 vol.
Hynes, H.B.N. 1970. The ecology of running waters. University of Toronto
Press. 555 pp.
Klecka, W.R. 1975. Discriminant analysis. Pp. 434-467 in Nie, N.H. et al.
S.P.S.S.: statistical package for the social sciences . McGraw Hill.
Klinger, S. and E.W. Trihey. 1984. Response of aquatic habitat surface areas
to mainstem disc!large in the Talkeetna to Devil Canyon reach o f the
Susitna River, Alaska. E. Woody Trihey and Associates. Report f or
Alaska Power Authority, Susitna Hydroelectric Project, Anchorage, AK .
Document 1693. 1 vol.
Milhous, R.T., D.L . Weyner, and T. Waddle. 1984. Users guide to the Ph y sical
Habitat Simulation System. Instream Flow I nformation Paper 11. U.S.
Fish Wildl. Serv. FWS/OBS -81/43 revised. 475 pp.
R&M Consultants,
Morphology.
Inc. 1982. Susitna Hydroelectric Project
Prepared for Alaska Power Authority, Anchorage, AK.
River
105 pp .
Schmidt, D.C. et al. 1984. Report No. 2. Resident and juvenile anadromous
fish investigations (May-October 1983). Susitna Hydro Aquatic Studies,
Alaska Dept . of Fish a n d Game. Report for Alaska Power Author i ty,
Anchorage, AK. Document 1784. 1 vol.
-65 -
Vining , L.J., J.S. Blakely, and G.M. Freeman. 1985. Report No. 5. Winter
Aquatic Investigations (September 1983-hay 1984). Vol. 1: An evaluation
of the incubation life-phase of chum salmon in the middle Susitna River,
Alaska. Susitna Hydro Aquatic Studies, Alaska Dept. of Fish and Game.
Report for Alaska P~er Authority, Anchorage, AK. Document 2658. 1 vol.
Williams, Shelley. 1985. The influence of project flows on hydraulic aspects
of mainstem and side channel rearing habitats in the Midale River for the
period May 20 to September 15. E. Woody Trihey and Associates.
Technical Memorandum for Alaska Power Authority, Susitna Hydroelectric
Project, Anchorage, AK. 43 pp.
Wishart, D. 1978. Clustan User Manual 3rd Edition. Program Library Unit,
Edinburgh University.
-66 -
APPENDIX 1
SPECIFIC AREAS DELINEATED ON THE 23000 CFS AERIAL PHOTOGRAPHY
-67 -
··~· ~ .·. . ·: ~ : .. ~:"r ··-
i~i. :~,~~~~~i.)\_.-\:Lz) · ~~~ .... ~?.?;:>~.:::: .... _. :~r.::;~~~~~~e
Specific areas from river
LEGEND:
L
R
u
Left
Right
Middle
RNR
Lt\R
il1S
Right Not Reconned
Left Not Reconned
Left Mainstem Spawning
Right Mainstem Spawning
Hiddle l1ainstem Spawning
T = Tributary
+ = River Mil e
-4-= F l o w Direc ti on
Speci:ic areas from river mile 104 to 110 at a mainstem discharge of 23000 cfs.
LEGEND:
L Left
R = Right
M Middle
RNR
LNR
LHS
Right Not Reconned
Left Not Reconned
Left Mainstem Spawning
RMS
t1MS
Right Mainstem Spawning
Middle Mainstem Spawning
T = Tributary
+ = Riv e r Hil e
.._ = Fl ow Direc t i o n
.... ,
0
Specific areas from river mile 110 to 115 at a mainstem discharge of 23000 cfs.
LEGEND:
L "' Left
K • Right
H = Middle
RNR Right Not Reconned
LNR : Left Not Reconned
L~S Left Mainstem Spawning
RHS • Right Hainstem Spawning
MHS • Middle Hainstem Spaw ~ing
T • Tributary
+ • River Mile
-.. = Flow Direction
Specific areas from river mile 115 to 121 at a mainstem discharge of 23000 cfs.
LPt;END :
L • Left
R -= Right
M • Middle
RNR ~ Right Not Reconned
LNR c Left Not Reconned
LMS • Left Mainstem Spawning
RHS • Right Hainstem Spawning
HHS "' Middle Mainstem Spawning
T = Tributary
+ "' River Mile
-.. .. Flow Direction
Specific areas fro• river mile 121 to 126 at a mainstem discharge of 23000 cfs.
LEGEHD:
L • Left
R • Right
~ • Middle
RNR c Right Not Reconned
LNR • Left Not Reconned
LHS • Left Hainstem Spawning
RHS a Right Hainstem Spawning
HMS • Middle Mainstem Spawning
T c Tributary
+ .. River Mile
-' = Flow Direction
Specific areas from river mile 126 to 132 at a mainstem discharge of 23000 cfs.
LEGEND:
L • Left
R • Right
M • Middle
RNR • Right Not Reconned
LNR • Left Not Reconned
LMS • Left Hainstem Spawning
RHS • Right Hainstem Spawning
HHS • Middle Mainstem Spawning
T • Tributary
+ • River Mile
~ = Flow Di r e ction
Specific areas from river mile 132 to 138 at a mainstem discharge of 23000 cfs.
LEGEND:
L • Left
R • Right
H • Middle
RNR • Right Not Reconned
LNR • Left Not Reconned
LMS • Left Hainstem Spawning
RMS • Right Hainstem Spawning
HHS • Middle Mainstem Spawning
T .. Tributary
+ .. River Mile
.._ • Flow Direction
Specific areas from river mile 138 to 144 at a mainstem discharge of 23000 cfs.
LEGEND:
L "' Left
R Right
M ,. Middle
RNR = Right Not Reconned
LNR • Left Not Reconned
LMS Left Mainstem Spawning
RMS • Right Mainstem Spawning
MMS • Middle Mainstem Spawning
T "' Tributary
+ River Mile
-' F!ow Direction
Specific areas from river mile 144 to 148 at a mainstem discharge of 23000 cfs.
U'.GEND:
L ... Letc:
R .. Right
M • Middle
RNR Right Not Reconned
LNR z Left Not Reconned
LMS z Left Hainstem Spawning
RHS Right Hainstem Spawning
HHS • Middle Mainstem Spawning
T .. Tributary
+ .. River Mile
~ Fl ow Direc tion
APPENDIX 2
METHODOLOGY
-77 -
TABLE OF CONTENTS
INTRODUCTION. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • .. • • • • • • • • • • • • • • • • 7 9
DELINEATION OF SPECIFIC AREAS............................................ 82
Distinctness/Indistinctness ••••••••••••••••••••••••••••••••••••••••• 82
Ground Truthing. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 83
HYDROLOGIC COMPONENT. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 8 4
Habitat Transformation Tracking ••••••••••••••••••••••••••••••••••••• 84
Breaching Flow Determination •••••••••••••••••••••••••••••••••••••••• 86
Cross Sectional Geometry oi Side Channel Head Berms ••••.•••••••••••• 87
Cross Sectional Geometry of Mainstem ••••••••••••••••••••••.••••••••• 88
Evaluation of Upwelling •••.••••••••••••••••••••••••••••••••••••••••• 88
HYDRAULIC COMPONENT. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 90
Mean Reach Velocity •••••••••••••••••••••••••••••••••••••••• ~ •••••••• 90
Sub s trate Size...................................................... 90
Channel Morphology.................................................. 92
STRUCTU'RAL COMPONENT. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 94
HABITAT INVENTORY TECHNIQUES............................................. 101
DESCRIPTION AND USE OF HABITAT INVENTORY FORM ••••••••••••••••••••••• 106
Pag£ One ••••••••••••••••••••••••••••••••••••••••••••••••••••••• 106
Page Two. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 112
Page Three •.••..•••••••••.•••••...•...••..•...••••••....••••••• 113
Page Four •••••••••••••••••••••••••••••••••••••••••••••••••••••• 114
-78 -
INTRODUCTION
The project team used two data sources to develop aquatic habitat
characterizations: (l) aerial photography; and (2) a habitat reconnaissance
data base. Additional Alaska Department of Fish & Game (ADF&G) information
was incorporated into the analyses from their habitat modeling program, their
fish utilization studies, and personal communications with their field
personnt:l.
Overlapping black and white aerial photography taken during the open water
season were available for nine Middle River discharges as measured at the USGS
Gold Creek gage (Table 18). These mainstem evaluation flows reflect probable
with-project flow characteristics. One set of winter aerial photography was
also available.
The investigators used aerial photography at several stages of the analysis:
(1) delineation of specific !!!!! including determination of the distinctness
or indistinctness of channel boundaries at each evaluation flow;
(2) determination of the breaching flow and wetted top width at the head berm
(hydrologic component); (3) the evaluation of plan form (hydraulic component);
and (4) structural component evaluation. The winter photography was useful in
detei"Clining whether upwelling occurred at individual specific areas. These
steps were required in order to track habitat transformation and stratify
specific areas into Representative Groups.
-79 -
Table 18. Use of black and white aerial photography in characterization of
aquatic habitat.
Specific Trilnsfor-
Hainstem Area Breaching mat ion Channel Upwelling
Discharg~(s) Date Taken Delineation Flows Tracking Geometry Ev aluation
2000-3000 March 1983 X
5100 10-14-84 X X X X
7400 10-04-84 X X
9000 10-08-83 X X X
10600 09-09-84 X X X
12500 09-11-83 X X X
16000 09-06-83 X X X
18000 08-2Q-80 X X
23000* 06-01-82 X X X
26900 08-27-84 X
*Reference flow for habitat transformation tracking.
Four field trips p r ovided the habitat reconnaissance data: a one-day trip on
August 21, 1984; a five-day trip September 3-7, 1984; a five-day trip
September 10-14; 1984, and a four-day trip September 29 to October 2, 1984.
The corresponding USGS Gold Creek gage discharges were approxiruately 18000,
11000, 10000, and 8000 cfs, respectively. The one-d,ty field trip was a trial
for the refinement of field procedures and the planning of future field work.
Observers completed a habitat inventory form for each of the 172 specific
areas over the course of the two five-day field trips. During the final field
trip the observers collected additional information to verify upwelling and
side channel breaching flows as well as mean reach velocities and habitat
transformation categorizations. A detailed list of equipment and procedures
used in the completion of the habitat inventory form appears in the Habitat
Inventory Techniques section.
-80 -
Following are detailed descriptions of the procedures and methods used i n the
hydrologic, hydraulic, and structural characterization of aquatic habitats of
the Talkeetna to Devil Canyon segment of the Susitna River (the Middle River).
-81 -
DELINEATION OF SPECIFIC AREAS
Aerial photography provided the basis for the delineation of portions of the
Middle River which are potentially important aquatic habitats. These proposed
study sites, termed specific~· were outlined on composite copies of black
and white photography at the mainstem evaluation flows of 23000, 16000, 12500,
and 9000 cfs. The specific areas consisted of representative mainstem areas
as well as nonmainstem areas such as side channels, upland sloughs, and side
sloughs. Of particular interest to this study were areas of the river that
exhibited different habitat characteristics at different flows, such as side
channels that became side sloughs at lower flows, mainstem areas that became
side channels, and wetted areas that dewatered. Determining areas of
upwelling was also important to this study. Specific areas were delineated
for study at areas of the Middle River where open leads were evident in the
winter photography in~icating the possible presence of upwelling.
DISTINCTNESS/INDISTINCTNESS
Locations that were not obvious channels at a particular mainstem eva~~~tion
flow sometimes transformed into obvious channels at a lower mainstem
evaluation flow. The distinctness of such physical features was an important
parameter in tracking habitat transformation.
An example of this is a margin of the mainstem which becomes a distinct side
channel separated from the mainstem by a gravel bar as the mainstem flow
recedes. The response of this "indistinct" mainstem habitat to receding flows
is different than that of the adjacent mainstem habitat, and they are
therefore separate specific areas.
-82 -
An indistinct boundary of a different nature occurs in areas that are turbid
~ainstem shoals at a high mainstem evaluation flow, but are clearwater shoals
at lower flows. This type of channel behavior is common in a number of the
mainstem chum salmon spawning areas.
GROUND TRUTHING
Aerial photographs served as guides in the first field surveys, facilitating
the location of each specific area from the air and on the ground. Generally,
the specific area delineated on the aerial photograph correctly defined the
bounds of a homogeneous aquatic habitat. In several instances shadows, dense
foliage, or incorrect interpretation of the nature of the water course had led
to a mistaken impression of the nature of a specific area. The outline of the
specific area was modified on the photographs to better reflect the actual
boundaries of the habitat type, or in several cases, a specific area was
divided into two specific areas of different habitat types. Several specific
areas were deleted from consideration after field observers determined that
they were tributaries rather than upland sloughs, or that they offered no
aquatic habitat value. As a result of these efforts, a total of 172 specific
areas were defined. These served as the foundation for further evaluation.
-83 -
HYDROLOGIC COMPONENT
HABITAT TRANSFORMATION TRACKING
Wetted surface area and site specific habitat type is a function of mainstem
discharge . Evaluation of the specific area habitat character istics apparent
in aerial photography wa s accomplished by the development of four binary
criteria. These flow dependent criteria included:
1. The presence of turbid or clear water. This is generally an
indicatio n of whether a specific area is breached (turbid) or
nonbreached (clear) at the subject mainstem evaluation flow.
2 . Visibly distinct or indiatinct channel boundaries. This criterion
distinguishes homogeneous habitats from adjacent habitats that
respond differently to mainstem flow.
3. Presence or absence of water. This distinguishes specific areas
that become dewatered. These specific areas may contain isolated
pools that, by definition, have no habitat value .
In addition, the imp o rtance of upwelling as a component of aquatic habitat was
acknowledged by the following criterion :
4. Presence or absence of upwelling which persists throughout the year.
This is evidenced by the presence or absence of open leads in the
March 1983 aerial photographs and the presence or absence of water
in the 5100 cfs aerial photography, or by field observations.
-84 -
The organization of these criteria into a flow chart for tracki ng h ab i tat
transformations between the mainstem evaluation flows of 23000 and 9000 cfs i s
depicted in Figure 8. It is important to note that the ~e criteria can be
applied be t ween any two mainstem evaluation f lows : however, for consistent
evaluation the 23000 cfs photography was used as t h e reference for monitoring
habitat tran~formation apparent in the lower flow aerial photography .
The determination of habitat transformation categories for each evaluation
flow at specific areas was not always c l ear-cut, relying frequently on the
discretion of the inve stigators.
required more deliberation than
Three of the branches of the flow chart
others. These decision nodes concerned
whether habitat was side channel or mainstem, a channel was. distinct or
indistinct. or whether a specific area was dewatered or not.
The distinction between side channel and mainstem habitat. as defined by
Klinger and Trihey (1984). is a good guideline for classifying habitat based
on aerial photo interpretation. Field experience gained during the habitat
inventory work. however. provided a more sensitive perspective of the
distinction between mainstem and side channel habitat than aerial photography.
At approximately 10000 cfs. mainstem channels were observed to
characteristically convey swifter velocities. have larger substrate. and be
oriented more directly downstream than side channels. Although discharge was
estimated for each channel during the field work, the observed character of
the habitat was weighted more than the percent of discharge conveyed in
discriminating between mainstem and side channel habitats.
-85 -
The transforaation of a channel from indistinct to distinct does not occur at
a discrete discharge. This process occurs over a range of flows as inundated
gravel-bars gradually dewater with decreasing mainstem stage, routing flow
through increasingly distinct channels. The precise discharge at which a
channel is judged to be distinct is not as important to the characterization
of these habitats as the process by which these channels emerge. It was
observed that indistinct channels typically have swifter flow velocities and
contain coarser substrate than perennial side channels.
The determination of whether a specific area was dewatered or not, although
sometimes apparent in the aerial photography, frequently relied on ground
verification. The definition of dewatered was expanded to include channels
that contained isolated pools that would imminently dewater or freeze s c lid,
thus voiding their value as fish habitat. These determinations always
required an on-site inspection.
BREACHING FLOW DETERMINATION
Two criteria of a specific area are fundamental to analysis of habitat type:
the presence or absence of water, and the turbidity or clarity of water.
Any nonmainstem specific area is defined as being breached if turbid mainstem
water is flowing through it. As mainstem flow decreases and the water surface
elevation of the mainstem drops below the head berm of the specific area, the
specific area transforms from breached to nonbreached. A nonbreached specific
area may be dry or contain clear water. If the latter, the water source is
upwelling groundwater or overland flow from a tributary.
-86 -
The determination of the mainstem flow at which a specific area becomes
breached or nonbreached is important in tt"acking habitat transformation. A
field survey would be the most direct and precise method of establishing
breaching flows, but such a survey would b~ very expens i ve. Field evaluation
would entail having an observer at each specific area, over the range of flows
under consideration, to record the mainstem flow at which the mainstem water
surface elevation overtops the head berm.
The series of black and white aerial photography from 5100 to 26900 cfs was
used as a visual reference frame for estimating breaching flows for specific
areas. Breaching flows were interpolated between photographed flows using
interpretive judgement and field obse rvations where applicable. It was not
possible to refine breaching flow estimates for specific areas that br~ached
significantly below 5100 cfs because of the lack of available information.
Some specific areas appeared "barely breached" in the 5100 cfs photography;
breaching flows were estimated at those sites. Bre a ching flow estimates above
26900 cfs relied exclusively on available ADF&G field information.
CROSS SECTIONAL GEOMETRY OF SIDE CHANNEL HEAD BERMS
The wetted top widths at the head berm of specific areas that persisted as a
d i sth 1ct side channel throughout most mainstem evaluation flows were used in
the analysis of channel geometry. The project team identified the head berm
for each channel using the lowest reference flow photography availaole
(5 100 cfs). Wetted top width across the head berm cross section was
determined at all mainstem evaluation flows with a divider. The distance
between the divider points was measured with a 40-division-per-inch scale.
-87 -
The investig<.tors plotted top width versus mainstem discharge for 46 specif ic
areas. The curves were then subjectively classified as steep, moderate, f lat ,
and irregular, based on their characteristic slope.
CROSS SECTIONAL GEOMETRY OF HAINSTEM
To better understand the influence of mainstem stage on side channel habitats,
the investigators performed a regional cross section analysis. They analyzed
mainstem cross sectional data from R&H Consultants (1982) over a stage
increase from 9700 to 23400 cfs at selected cross sections distributed
throughout the Middle River (Table 4). The difference between the high and
low flow water surface elevations at each section was scal ed and the resultant
stage increase was recorded in feet.
EVALUATION OF UPWELLING
Clearwater habitats occur in channels whose water source is local surface
water runoff and/or upwelling groundwater. The investigators used aerial
photography and field observations to determine upwelling areas.
The project team examined each specific area in the winter photography for the
presence or absence of open leads. While open leads can be caused by h i gh
velocities, it was relatively ea.sy to differentiate between velocity leads and
those caused by a temperature differential created by upwelling groundwater.
The presence of clearwater in the 5100 cfs photography suggested upwelling in
many areas.
-88 -
Field observers made an on site evaluation at every specific area. In
clearwater areas, upwelling was indicated ty the presence of small "volcanoes"
in the substrate caused by upwelling flow. The presence of upwelling was
impossible to determine in most breached areas unless the flow of turbid water
was minimal. Upwelling in these specific areas could be determined only by
evaluation of aerial photography.
-89 -
HYDRAULIC COMPONENT
MEAN REACH VELOCITY
Three methods were used to determine mean reach velocity. The first method
involved estimating the surface velocity by recording the time it took a
floating object to travel a known distance. The mean reach velocity was
estimated as 85 percent of this surface velocity. The second method involved
measuring the height (h) that water "climbed" a survey rod held perpendicular
to the flow (i.e •• conversion of kinetic energy to potential energy). The
relationship between h and mean reach velocity is depicted in Figure 13.
Tabulated valves of velocity corresponding with particular heights appear in
Table 19. On rare occasions. a Harsh HcBirney Type 201 portable ~urrent meter
with wading rod was used to measure velocity. Velocity was measured at a
point 0. 6 times the depth from the water surface elevation for depths less
than or equal to 2.5 ft. Velocity was determined as the average of
measurements made at 0. 2 and 0.8 times the depth from the water surface
elevation for depths greater than 2.5 ft. (Note: a Marsh HcBirney was used
primarily to check the accuracy of the two approximate methods of estimating
mean reach velocities).
SUBSTRATE SIZE
Field observers coded the characteristic size of the largest bed materials of
a specific area. Frequently. more than one code was selected because of the
evenly balanced mixture of fine and coarse substrate size classes at many
specific areas. The substrate type and corresponding code numbers are
presented in the Habitat Inventory Techniques section.
-90 -
v = J 2gh
g 2 32.2 ft /sec 2
h = height in feet (ft)
water level
-flow direction
Figure 13. The relationship between height (h) and mean reach velocity as
depicted by the rise of the iiater column against a staff held
perpendicular to the flow.
Table 19. The relationship between the height (h) that water climbs a staff
when held perpendicular to the flow and mean reach velocity .
Height (ft) Velocity (fps) Height (ft) Velocity (fps)
0.01 0.8 0.14 3.0
0.02 1.1 0.15 3.1
0.03 1.4 0.16 3.2
0.04 1.6 0.17 3.3
0.05 1. 8 0.18 3.4
0.06 2 .0 0.19 3.5
0.07 2.1 0.20 3.6
0.08 2.3 0.21 3.7
0.09 2.4 o. 22 3.8
0.10 2.5 0.24 3.9
0.11 2.6 0.26 4.1
0.12 2.8 0.28 4.2
0.13 2.9 0.30 4.4
-91 -
CHANNEL MORPHOLOGY
Plan form analysis of each specific area containing a distinct side channel
entailed measurement of selected physical parameters. such as angular
orientation to the mainstem, total length, straight line length from channel
head to mouth, and representative bank-full top width. Length and width were
measured using a Numonics Corporation Electronic Graphics Calculator and Model
2400 Digi Tablet from aerial photographs that had been enlarged to a scale of
1 inch•250 feet. Orientation angle was determined by drawing two lines. one
parallel to the mainstem flow, and one parallel to the flow of the side
channel near the head. The inside angle formed by these lines was measured
using a protractor .
Sinuosity was calculated for each specific area as the ratio of total channel
l'!ngth to straight-line length between channel head and mouth. A straight-
line channel has a 1 :1 ratio. This ratio increases with increased sinuosity.
Channel length to width ratios were also calculated for each specific area.
The following groups of variables were subject to cluster analysis using
Ward's Method, followed by a discriminant analysis using the direct entry
method: length, width, length to width ratio, sinuosity, and number of bends.
The number of cases (specific areas) utilized in the analysis was limited to
70. This was the total number of specific areas which contained a distinct
side channel.
Cluster analysis is undertaken to sort cases into groups such that the degree
of association is high between members of the same group and low between
members of different groups (Wishart 1978). Seven clustering methods are
-92 -
available from the SPSS-X package (Statistical Procedures for the Social
Sciences-Version X): Between groups average, Within groups average, Single,
Complete, Centroid, Median, and Ward. Of these seven methods, Wishart (1978)
considers Ward's method the best method for finding minimal variance spherical
clusters. Ward's method was used in this study to identify groups of specific
areas that are morphologically similar. Once well defined clusters are formed
from a cluster analysis, it is possible to determine which variables
contribute most to their separation. A suitable approach is to set up
discriminate functions using a multiple discriminant analysis. The relative
importance of the variables under consideration can be determined by reviewing
the coefficients in these discriminating functions. It forma a number of
linear functions of the environmental variables under consideration, usually
one less than the number of groups used in the analyais. The weighting
coefficients (standardized discriminant function coefficients) for each of the
variables identify those which contribute most to the separation of the groups
along each respective function (Klecka 1975). Numerical values give the
percentage variances that are accounted for by each function. Signs for the
coefficients indicate whether the variables are positively or negatively
correlated. Multiple discriminant function analysis was used in this study to
identify the most important variables for the discrimination of
morphologically zimilar groups.
-93 -
STRUCTURAL COMPONENT
The structural componen t was characterized by the following variables:
dominant cover; percent cover; substrate size; substrate embeddedness; channel
cross sectional geometry; and streambank vegetation.
Structural habitat indices (SHI) represent the synthesis of the six structural
habitat variables into a single val ·~e. The procedure to derive structural
habitat indices involves three s~eps: (1) rating the effect of each variable
on juvenile salmonid habitat quality for each specific area; (2) ranking the
relative importance of each variable to juvenile salmonid habitat quality; and
(3) combining ratL1g and weighting factors into a structural habitat index for
each specific ar .a. An explanation of each step follows.
The basis for rating each structural habitat variable was information obtained
from habitat inventory and aerial photo procedures. The precision of this
information permitted the rating of each variable into the following
categories: excellent, good, fair, poor, and nonexistent. These rating
categories were assigned numerical values of 1.0, 0.75, 0.50, 0.25, and 0.0,
respectively.
Dominant cover and percent cover were rated as a variable combination to allow
the use of ADF&G clearwater cover suitability criteria for juvenile chinook
salmon in the rating process (Table 20). Clearwater criteria were selected
rather than turbid water criteria because of their independence from the
influence of turbidity as a cover variable. The clearwater criteria were thus
-94 -
assumed to be more directly related to structural cover as described by
dominant cover and percent cover codes (see Habitat Inventory Techniques
section). Juvenile chinook salmon criteria were used because they are primary
evaluation species in Middle River instream flow studies (E. Woody Trihey &
Associates and Woodward-Clyde Consultants 1985).
table 20 . Cover suitability criteria recoauended for use in modeling juvenile chinook habitat
under clear water conditions (Schmidt et al . 1984).
COVER TYPE
Cobble or
Percent No Emergent Aquatic Large Rubble Boulders Debris & Overhanging Undercut
Cover Cover Veg. Ve~. Gravel 3"-5" 5" Deadfall Riparian Banks
Clear Water (ADF&G)
0-5% 0.01 0.01 0.07 0.07 0.09 0.09 0.11 0.06 0.10
6-25% 0 .01 0.04 0.22 0.21 0.27 0.29 0 .33 0.20 0.32
26-50\ 0.01 0 .07 0.38 0.35 0.45 0.49 0.56 0.34 0.54
51-75% 0.01 0.09 0.53 0.49 0.63 0.69 0.78 0.47 0.75
76-100\ 0.01 0 .12 0.68 0.63 0.81 0.89 1.00 0.61 0.97
The suitability criteria for cover were used in the rating process by dividing
the range of suitability index values into discrete intervals, each
corresponding to a rating factor, as follows: 0.0 (nonexistent), 0.01-0.10
(poor), 0.11-0.30 (fair), 0.31-0 •. 50 (good), and 0.51-1.0 (excellent). The
professional judgement of EWT&A and AEIDC staff biologists was used to
establish these intervals. The rating factory for dominant cover and percent
cover codes for each specific area was thus obtained by classifying the
corresponding suitability index into one of the above intervals. A matrix of
dominant cover and percent cover rating factors appears as Table 21.
-95 -
Table 21. Dominant cover/percent cover rating factors.
Dominant Cover Code
Percent
Cover Code 1 2 3 4 5 6 7 8 9
l 0 .00 0.00 0.25 0.25 0.25 0.25 0.50 0.25 0 .50
2 0.00 0.25 0.50 0.50 0.50 0.50 0.75 0.50 0.75
3 0.00 0.25 0 .50 0.75 o. 75 o. 75 1.00 0.75 1.00
4 0.00 0.25 1.00 0.75 1.00 1.00 1.00 0.75 1.00
5 0.00 0.50 1.00 1.00 1.00 1.00 1.00 1.00 1.00
6 0.00 0.50 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Channel morphology was evaluated as a structur~l habitat variable on the basis
of the approximate proportions that three general types of channel cross
sectional geometry were represented at each specific .uea. The three cross
sectional types are as follows: (1) broad cross sections with gentle-sloping
banks; (2) cross sections with one gentle-sloping bank and one steep bank; and
(3) cross sections that are incised with two steep banka. The first cross
sectional geometry type has a positive correlation with habitat availability
for juvenile salmonids by providing relatively large wetted surface area per
unit discharge anJ proportionately larger areas along channel margins where
edge effects retard velocities to suitable levels. Cross sectional geometry
with one gentle-sloping bank ... as rated half as valuabi.e as cross sectional
geometry with two gentle-slop ing banks. Incised cross sectional geometry with
steep banks received a zero rating factor. Streambank slope codes (see
Habitat Inventory Techniques section) and aerial photo interpretation were
used to evaluate the cross sectional geometry of each specific area. Table 22
lists channel morphology rating factors for various proportions of cross
sectional geometry types that could be represented at a specific area. These
-96 -
rating factors reflect the professional judgement of EWT&A and AEIDC staff
biologists.
Table 22 . Channel morphology rating factors.
Channel Cross
Sectional
Geometry Type
2 gentle-sloping
sides
1 gentle-sloping
side
2 steep sides
Rating Value
1.00 0.75 0.75
0.00 0.25 0.00
o.oo 0.0 0 0.25
=r-•a:aw
1.00 1.00 0.75
Percentage of Cross Sectional Geometry Type
0.50 0.50 0.25 0.00 0.50 0.25 0.25 0.00 0.25 o.oo 0 .00
0.50 0.25 0.75 1.00 0.00 0.50 0.25 0.75 0.00 0.25 0 .00
0.00 0.25 o.oo 0.00 0.50 0.25 0.50 0.25 0.75 0.75 1.00
C.75 0.75 0.75 0.50 0 .50 0.50 0.50 0.50 0.25 0.25 o.oo
The channel morphology rating factors assume that velocities prohibitive to
juvenile salmonids occur in the primary flow corridor of each specific area.
While this is true for the preponderance of side channel habitats during
breached conditions in the Middle River, it is not true for upland sloughs and
side channel habitats that are nonbreached. For this reason, upland slough
habitats, which seldom have velocities that are prohibitive to juvenile
salmonids, were all rated as excellent for channel morphology. This
effectively eliminated channel morphology as a discriminating factor of
structural habitat quality between .upland sloughs. Side channel habitats were
evaluated for breached conditions only, when it could be assumed that cross
sectional geometry was correlated with the availability of channel margin
habitats possessing suitable velocity for juvenile chinook salmon. The
nonbreached phase of side channel habitats (side slough habitat) is less
heavily utilized by juvenile chinook salmon (Schmidt et al. 1984).
-97 -
Dominant substrate size and substrate embeddedness were rated as a variable
c011bination according to the rating factor matrix that appears as Table 23.
Substrate size and embeddedness codes are explained in the Habitat Inventory
Techniques section. Table 23 reflects the professional judgement of EWT&A and
AEIDC staff biologists. In general, the larger and less embedded substrate
was rated as having the most positive effect on juvenile salmonid habitat
quality. Larger substrate provides more extensiv e protection from high flow
velocities. Less embedded substrate has more interstitial space available for
occupation by juvenile fish.
Table 23. Substrate size/embeddedness rating factors .
Substrate Size Code
Embedded ness
Code 1 2 3 5 6 7 8 9 10 11 12 13
1 0.00 0.00 o.oo 0 .00 0.00 0.25 0.25 0.25 0.50 0.50 0 .50 0.50 0 .50
2 0.00 0 .00 0.00 o.oo 0 .25 0 .25 0 .25 0 .50 0 .50 0. 75 0 .75 1.00 1.00
3 0.00 0.00 0 .00 0 .25 0.25 0.50 0.75 0.75 1.00 1.00 1.00 1.00 1.00
Streambank vegetation codes (see Habitat Inventory Techniques section) and
aerial photography were used to evaluate the extensiveness of streambank
vegetation for each specific area. Channel width was also considered in the
evaluation of ratin~ factors because the relative effect of streambank
vegetation on overall channel habitat quality is a function of width.
Streambank vegetation as a structural habitat variable affects shading,
terrestrial insect import, and bank stability. Vegetation as a cover
parameter is included in the dominant cover coding discussed earlier. The
rationale behind the assignment of r ating factors is r eflected in Table 24.
-98 -
Actual ratings of streambank vegetation were assessed for each specific area
based on professional judgement.
Table 24. Streamside vegetation rating factors.
Rating
Factor
Narrow Channel/Extensive Vegetation 1.00
Moderate Channel Width/Extensive Vegetation 0.75
Moderate Channel Width/Moderate Vegetation 0.50
Wide Channel/Extensive Vegetation 0.25
Wide Channel/Moderate Vegetation 0.00
Weighting factors were developed for each of the variable/variable
combinations based on the professional judgement of EWT&A and AEIDC staff
biologists. Several relative rankings were discussed. In the final analysis,
relative weighting factors were accepted because their application in the
calculation of SHis produced numerical results that corroborated subjective
evaluations of structural habitat quality recorded during habitat inventory
procedures. A summary of the weighting factors for each structural habitat
variable appear in Table 25.
Table 25. Structural habitat variables and their corresponding weighting
factors.
Habitat Variable/Order of Importance
Dominant/Percent Cover
Channel Cross Sectional Geometry
Substrate Size/Substrate Embeddedness
Streamside Vegetation
-99 -
Weighting
Factor
0 .45
0.30
0.20
0.05
Rating and weighting factors were combined in a matrix that provided a
convenient form for evaluating structural habitat indices (Figure 14). By
summing the produ~ts of the rating and weighting factors for each structural
habitat variable, a structural habitat index value is obtained for the subject
specific area. This process was repeated for all 172 specific areas
inventoried in the Middle River.
Figure 14. Structural habitat index form.
Habitat Variable Weighting Factor
Dominan .. Substrate Size/
Habitat Cover/Percent Channel Substrate Streamside
Quality Cover Geometry Embe · 1edness Vegetation
Rating Factor (0.4S) (0.30) (0.10) (O.OS)
Excellent ( 1. 00) .4S .30 • 20 .OS
Good (0.7S) .34 .22S .1S .037
Fair (O.SO) .23 .1S .10 .02S
Poor (0.2S) .11 .07S .OS • 012S
Non-Existent (0.0) .0 .0 .o .o
••••••••••••=•••••••••••••••••••=••••••••===•••••••=••••••••==z•••••••===•••••
Product of
rating and
weighting
factors
SHI •
?
-100 -
? ? ?
HABITAT INVENTORY TEClffiiQUES
The habitat reconnaissance work was based on the premise that the habitat
characteristics of each specific area could be averaged in order to develop a
reliable composite description of the entire area. The intent was to describe
the habitat in general terms (for example, mean reach velocity) and not to map
localized habitat features.
The development of the habitat inventory forms (Figure 15) provided a
framework for the field reconnaissance work. These forms were designed to
facilitate a cost-effective means of gathering reliable field observations
based on visual assessment and minimal field measurements.
Se,reral factors were considered while developing the habitat inventory form.
These included : (1) the total time frame allocated for the habitat inventory
task (approximately one month); (2) the large number of specific are~s to be
surveyed; (3) a limitation of approximately one hour per spec ~fic area;
(4) the use of minimal field gear for ease in transportation a t each s rectfic
area and during helicopter transport; (5) compatibility with ADF&G data; and
(6) ease in computer data management. The methods and field techniques for
completing the habitat inventory form are described below.
-101 -
Sheet 1 of _
Habitat Inventory
Crew: -------------------Date:
Time:
A.M.:
Location: ----------------
Mainstem Dis<;.harge:
Category: ____ _
Breached? Yes/No
Mean Reach Velocity:
Site Specific Discharge:
Estimated/Measured
Estimated/Measured
Does Upwelling Occur? Yes/No/Cannot Be Detected Visually
Do Tributaries Enter the Slough or Side Channel? Yes/No
If Yes, Description of Tributary (size, location):_----------
Head Gage: ______ _ W SEL: Remarks:
Mid-Reach Gage: WSF.L:
Mouth Gage: WSEL:
S ubstrate: 1 2 3 4 5 e 1 8 9 10 11 12 13
Substrate Embeddedness: 1 2 3
Dominant Cover Code: 1 2 3 4 5 6 7 8 9
Percent Cover: 1 2 3 4 5 6
Streambank Slope: LB 1 2 3 Stable/Unstable RB 1 2 3 Stable/Unstable
Streambank Vegetation: LB 1 2 3 4 R8 1 2 3 4
Representative Top W i dth: Bankfull Top Width:
Representative Depth: Bankfull Depth:
Water Clarity: Clear/Turbid _____ ft.
Length of Backwater: ------Estlmat~d/Measured
Were Fish Observed? Yes/No
Adult: Chinook ___ Coho __ Sockeye ___ Chum ___ Pink ___ _
Juvenile: Chinook _Coho ___ Sockeye __ c h um __ Pink __
ReMarks:
Figure 15 . Habitat inventory form.
Sheet 2 of
Habitat Inventory
Crew: ---------------------------------Date: ----------
Time:
R.M.:
Site Sketch & Habitat Mapping Flow Description & Remarks
Habitat Type Proportions: Pool ---Riffle ____ Run
Habitat Quality Proportions: 1 ___ 2 __ 3 __ 4 ____ 5 ___ _
Figure 15. (cont'd)
-103 -
EWTAA
Habitat Inventory
Crew: --------------------------------
PHOTOGRAPHS
No. Description
Figure 15. (cont 'd)
-104 -
Sheet 3
Date: ----------
Time: -----------
R.M.:
Film I.D. No.: ____ _
EWTAA
Habitat Inventory
Crew: ____________________________ ___
DETAIL: Sketch and Description
Figu-::-e 15. (cont 'd)
-lOS -
Sheet '-
Date: ____ _
Time: ----------
R.M.:
EWTAA
Both field crews were in the he licopter for initial morning flights . Upon
reaching a specific area, an overflight of the area was used to : {1) ensure
that the proper specific area was being visited; and (2) obtain a general
overview of the area to determine features such as flow patterns, whether the
specific area was breached or not, backwater influence, etc. Low altitude
aerial photos ere also taken at this time. The helicopter would then land
and drop off the first crew to complete the ground survey and fill in the
habitat inventory form. A separate form for each specific area was filled
out. The remaining crew would then proceed to the next specific area
downstream of the first team and complete that area. This "leap-frogging"
down the river was a fast and efficient way of covering many specific area ~
each day. On the average, 27 specific areas were visited per day.
DESCRIPTION AND USE OF THE HABITAT INVENTORY FORM
PAGE ONE
Crew: A minimum of two people were sent to evaluate each specific area. Two
people were important because of the subjectivity of the work. The ability to
discuss the habitat and work out perceived differences helped remove most of
the individual bias from the data. The names of the individuals were entered.
Date and Time: The date and time a specific area was visited was recorded.
R.H.: Each specific area was referenced to a river mile with respect to the
mainstem looking upriver: left (L), right (R), or middle (H) if between two
mainstem forks. The river mile was entered.
-106 ·-
Category: The perceived habitat transformation cat~gory of the specific area
was recorded.
Location: This was used if another designation was commonly used to reference
the specific area.
Mainstem Discharge: This data was obtained from USGS records at Gold Creek.
Breached: Whether the channel head berm was breached or not was recorded.
Mean Rea .:h Velocity: Three methods were used in estimating mean reach
velocities. These methods were discussed iu detail in the Hydraulic Component
section.
Site Specific Discharge: The discharge was estimated using the equation
Q•V(W)(d), where V is estimated m~an reach velocity (fps), W is the
representative top width (ft), and d is the mean depth of the portion of the
top width conveying most of the flow (ft).
Does Upwelling Occur: Visual detection was recorded as positive if actual
upwelling was observed as a volcano-like structure in fine sediments or as
gravel seepages seen primarily along and close to the banks. If an area was
breached, turbidity made it difficult to determine if upwelling occurred. A
response of "cannot be detected visually" was then appropriate. A negative
response was recorded only if a channel was dewatered or consisted of isolated
pools.
-107 -
Do Tributaries Enter the Slough or Side Channel?: If one or mo r e tributaries
entered the specific area, a brief description of each was recorded.
Information included where it entered the specific area, its estimated
discharge, and the effect this additiona l inflow has on fish habitat .
Head Gage, Mid-Reach Gage, Mouth Gage: One or more staff gages were
occasionally in plac e within the specific area. If so, the water surface
elevation and gage number was recorded, as well as any remarks about the
condition of the gage (bent or broken).
Substrate: The coding scheme and methods chosen for this habitat inventory
parameter corresponded directly with ADF&G survey methodology (Estes and
Vincent-Lang 1984). The preliminary field trip included ADF&G personnel to
explain the coding procedure. The substrate type and corresponding code
numbers follow:
Code .!I.£! Size (inches)
1 Silt
2 Silt and Sand
3 Sand
4 Sand and Small Gravel
5 Small Gravel 1/8 -1
6 Small and Large Gravel
7 Large Gravel 1 - 3
8 Large Gravel and Rubble
9 Rubble 3 -5
10 Rubble . and Cobble
11 Cobble 5 -10
12 Cobble and Boulder
13 Boulder 10+
-108 -
This was one of the more difficult parameters to average for a n en t ire
specific area. For this reason, several codes indicating substrate s ize were
often chosen and a map indicating substrate zones within the specific area was
drawn on page two of the habitat inventory form. The overall characteri stics
of the substrate in a specific area were quickly and easily recorded in this
manner.
Substrate Embeddedness: Substrate embeddedness descriptions and their code
numbers are as follows :
Code
1
2
3
Description
Embedded, consolidated, and cemented
Embedded but not cemented
Not embedded
Embeddedness implies a larger substrate material partially or fully buried in
smaller material. If a substrate constituent was not embedded in smaller
material it was coded number 3. Substrate that was partially embedded but not
consolidated was coded a number 2. The degree of consolidation was determined
mainly by trying to penetrate the upper substrate layer with a boot. If the
upper layer was difficult to break through, then the substrate was considered
cemented for a substrate embeddedness code of 1.
Dominant Cover Code : The codes used were developed by ADF&G (Schmidt et al.
1984) and are as follows:
-109 -
Code
1
2
3
4
5
6
7
8
9
No Cover
Emergent Vegetation
Aquatic Vegetation
Large Gravel
Rubble
Cobble/Boulder
Debris/Deadfall
Overhanging Riparian
Undercut Banks
One code was chosen only if the cover available in the specific area was
dominated by one type. More than one cover code was recorded if the available
cover in a specific area was a mixture of types.
Percent Cover: This number indicates the percentage surface area available as
cover to juvenile fish. These codes were developed by ADF&G (Schmidt et al.
1984) and are presented below :
Code Percent Cover
1 0-5
2 6-25
3 26-50
4 51-75
5 76-95
6 96-100
Streambank Slope: Streambank slope and stability for both the left and right
banks was recorded. The slope was determL1ed to be steep if the horizontal to
vertical ratio was greater than or equal to 1:1 (code number 1); moderate if
the ratio was between 1 :1 and 20:1 (code number 2); and flat if the ratio was
greater than 20:1 (code number 3). The streambank stability was determined by
observing the composition of each bank. Sandy banks and broad, flat gravel
-110 ..•
bars were generally considered the least stable while rocky o r heavily
vegetated banks were considered more stable .
Streambank Vegetation: The vegetation for each bank was recorded according to
the following codes:
Code
1
2
3
4
Description
Less than 50 percent of streambank vegetated
Dominant vegetation is grass
Dominant vegetation is of tree form
Dominant vegetation is shrub
Two or more codes were used if one code did not adequately describe the
vegetation. The areas of differi~g vegetation were then noted on page two of
the habitat inventory form.
Representative Top Width. Bankfull Top Width. Representat ive Depth. and
Bankfull Depth : Depth was measured using a yardstick or surveyor rod and
distances were determined usin~ either a Ranging 600 range finder or
fiberglass tape. Bankfull top widths and bankfull depths were sometimes
impossible to measure. A shoal is an excellent example; shoals areas have
only one bank. Some difficulty in determining the water line for bankfull
depths was encountered. This was overcome by observing indicators such as
debris lines. water stained or dirty rocks. damage to streambank vegetation.
or from the channel morphology.
Water Clarity: Water within each specific area was determined to be clear or
turbid. If it was turbid the depth. in feet. of how far one could see into
-111 -
the water was determined by reading the lowest visible 1~rk on a survey rod or
yardstick.
Length of Backwater: The intrusion of backwater was either measured or
estimated, in feet, from the point of t he confluence with th e mainstem.
Were Fish Observed?: Determination of fish presence was through visual
observation. Information recorded included the pre~ence or absence of fish,
whether the fish was an adult or juvenile. the species, the abundance, and the
activity (spawning adults for example). To ensure positive ider.t ification of
juvenile fish. attempts were made to capture a sample using either a beach
seine or a hand-held dip net. The beach seine. used primarily in turbid
water, proved to be too time consuming. The use of this form of capture was
discontinued after the first field trip.
PAGE TWO
Page two of the habitat inventory form again begins with the crew. date, time.
and specific area designation.
Site Sketch and Habitat Mapping: A sketch of each specific area was drawn.
Additionally. any notes or insights about the area were recorded here.
Information on plan form; habitat types; discharge; velocities; size of pools,
riffles, runs. and their relative · proportions; fish usage; general slope or
gradient of the streambed; substrate; vegetation; fish activities; and any
other information which would help expand on the descript~ons of page one to
further characterize the habitat of each specific area was recorded.
-112 -
Habitat Type Proportion~: After the first fie l d trip it became apparent t ha t
a description of the proportions of habitat would help more fully d es c ribe the
specific area, so this parameter was added. An estimate of the percentage of
pool and/or riffle and/or run for the entire specif ic area was recorded.
Habitat Quality Proportions: This was another parameter included after the
first field trip. The study team felt it was very important to be able to
record general impressions of the overall quality of the habitat at each
specific area. The habitat quality proportions are only for juvenile fish. A
percentage figure was recorded for each of the following codes :
Code Description
1 No habitat value
2 Habitat quality was poor
3 Habitat quality was fair
4 Habitat quality was good
5 Habitat quality was excellent
For example, a specific area could have been recorded as 20%, code 2, poor
habitat; 30%, code 3, fair habitat; and 50%, code 4, good habitat. Habitat
quality proportions were based on the study teams knowledge of fishery
habitats.
PAGE THREE
Page three of the habitat form was used to record photographs taken at each
site . The header information is the same on this page as previous pages with
the addition of film I.D. Number. The film roll number and initials of the
photographer were recorded. The number of individual photos and their
corresponding description make up the rest of the page . Photographs were
-113 -
taken to help describe the specific area in general, or a particular f ea t ure
of the area (such as substrate).
PAGE FOUR
Page four of the form was used for additional notes or detailed drawings which
would help further des cribe a specific area.
-114 -
APPENDIX 3
AQUATIC HABITAT TRANSFORMATIONS OF SPECIFIC AREAS
OF THE MIDDLE SUSITNA RIVER
AT SEVERAL MAINSTEM DISCHARGES REFERENCED TO 23000 CFS
-115 -
APPENDIX 3
Aquatic Habitat Transformations of S ~e cific Areas
of the Middle Susitna River
at Several Hainstem Discharges
Referenced to 23000 cfs
Mainstem Q(cfs)
River
Mile 23000 18000 16000 12500 10600 9000 7400 5100
100 .40 R sc 4 4 2 2 2 2 2
100.60 R ss 1 1 1 1 1 1 1
100.60 L sc 4 4 4 4 3 3 3
100.70 R MS 10 10 4 4 4 4 4
101.20 R sc 4 4 4 4 2 2 2
101.30 M sc 4 4 4 4 9 9 9
101.40 L sc 2 2 2 2 2 2 2
101 .50 L MS 10 10 10 10 4 4 4
101.60 L sc 4 4 2 2 2 2 2
101 .70 L sc 4 4 4 4 3 3 3
101.71 L t ~~C) 8 8 8 8 9 9 9
101.80 L sc 2 2 2 2 2 2 2
102.00 L sc 4 4 4 4 9 9 9
102.20 L us 1 1 1 1 1 1 1
102.60 L sc 4 4 4 4 4 4 3
104.00 R IMS 6 6 6 6 6 6 6
104.30 M sc 4 3 9 9 9 9 9
105.20 R us 1 1 1 1 1 1 1
105.70 R MS 10 10 10 10 10 10 10
105.81 L MSS 6 6 6 6 6 6 6
106.30 R sc 4 4 4 4 4 4 4
107.10 L sc 4 4 4 4 3 9 9
107.60 L us 1 1 1 1 1 1 1
108.30 L us 1 1 1 1 1 1 1
108.70 L MS 10 10 4 4 4 4 4
108.90 L MS 10 10 10 10 10 10 10
109.30 M MSS 6 6 6 6 9 9 9
109.40 R MS 10 10 10 10 10 10 10
109.50 M sc 4 4 9 9 9 9 9
110.40 L sc 4 4 4 2 2 2 2
110.80 M sc 4 4 4 4 4 4 4
111 .00 R MS 10 10 10 10 10 10 10
111.50 R MS 10 10 4 4 4 4 4
111.60 R MSS 6 6 6 8 8 9 9
112.40 L sc 9 9 9 9 9 9 9
112.50 L us 1 '· 1 1 1 1 1
112.60 L MS 4 4 4 4 4 4 4
Habitat Type at Reference Flow SC • Side Channel
IMS • Indistinct Mainstem SS • Side Slough
MSS • Mainstem Shoal US • Upland Slough
ISC • Indistinct Side Channel MS • Mainstem
-116 -
River
Mile 23000 18000 16000 12500 10600 9000 7400 5100
113.10 R ss 1 1 1 1 1 l 1
113.60 R IMS 6 6 6 6 8 8 8
113.70 R ss 1 1 1 1 1 l 1
113.80 R IHS 6 6 6 6 6 6 6
113.90 R IMS 6 6 6 6 6 6 8
114.00 R HS 4 4 4 4 4 4 4
114.10 R ISC 5 5 5 5 5 5 5
115.00 R sc 4 4 4 2 2 2 2
115.60 R sc 2 2 2 2 2 2 2
116.80 R HS 10 10 4 4 4 4 4
117.00 H ISC 6 6 8 8 8 9 9
117.10 H sc 4 4 3 3 3 3 3
117.20 H sc 3 9 9 9 9 9 9
117.70 L IMS 6 6 5 5 5 5 5
117.80 L sc 4 4 4 4 4 2 2
117.90 R sc 4 4 4 4 4 4 3
117.90 L sc 2 2 2 2 2 2 2
118.00 L sc 3 3 3 3 3 3 3
118.60 H ISC 5 5 8 8 8 8 8
118.91 L MSS 6 6 6 6 6 6 6
119.11 L HSS 6 6 6 6 6 6 6
119.20 R sc 4 4 4 4 3 3 3
119.30 L sc 4 4 2 2 2 2 2
119.40 L us 1 1 9 9 9 9 9
119.50 L sc 4 4 4 4 4 4 4
119.60 L sc 4 4 4 4 4 4 4
119.70 L sc 2 2 2 2 2 2 2
119.80 L sc 4 4 9 9 9 9 9
120.00 R us 1 1 1 1 1 1 1
120.00 L sc 4 4 3 3 3 9 9
121.10 R IMS 6 6 6 6 6 6 5
121.10 L sc 4 4 4 4 4 4 3
121.50 R sc 3 3 3 3 9 9 9
121.60 R sc 4 4 3 3 9 9 9
121.70 R HS 10 10 4 4 4 4 4
121.80 R sc 3 3 3 3 3 3 3
121.90 R us 1 1 1 1 1 1 1
122.40 R ss 1 1 1 1 1 1 1
122.50 R sc 2 2 2 2 2 2 2
123.00 L sc 4 4 4 4 4 4 4
123.10 R us 1 1 1 1 1 1 1
123.20 R ISC 8 8 8 8 8 8 9
123.30 R us 1 1 1 1 1 1 1
123.60 p, ss 1 1 1 1 1 1 1
Habitat Type at Reference Flow SC • Side Channel
IMS • Indistinct Mainstem SS • Side Slough
MSS • Mainstem Shoal US • Upland Slough
ISC • Indistinct Side Channel MS • Mainstea
-117 -
River
Mile 23000 18000 16000 12500 10600 9000 7400 5100
124.00 M ISC 7 7 7 7 7 7 7
124.10 L MS 10 10 10 10 10 10 4
124.80 R ISC 8 8 8 8 8 8 9
125.10 R sc 2 2 2 2 2 2 2
125.20 R MS 4 4 4 4 4 4 4
125.60 L MSS 6 6 6 6 5 5 5
125.60 R sc 9 9 9 9 9 9 9
125.70 R sc 4 4 4 4 4 4 4
125.90 R ss 1 1 1 1 1 1 1
126.00 R ss 1 1 1 1 1 1 1
126.30 R sc 4 2 2 2 2 2 2
127.00 M sc 4 4 4 4 4 4 4
127.10 M IMJ 6 6 6 5 5 5 5
127.20 M us 1 1 1 1 1 1 1
127.40 L MS 10 10 10 10 10 4 4
127.50 M ISC 6 6 6 6 5 5 5
128.30 R IMS 6 6 6 6 6 6 6
128.40 R MSS 6 6 6 5 5 9 9
128.50 R sc 4 4 4 4 2 2 2
128.70 R sc 4 4 2 2 2 2 2
128.80 R sc 4 2 2 2 2 2 2
129.30 L IMS 10 10 10 10 5 5 5
129.40 R us 1 1 1 1 1 1 1
129.50 R ISC 6 6 5 5 5 5 5
129.80 R MS 10 10 10 10 10 10 10
130.20 R sc 4 4 4 2 2 2 2
130.20 L sc 4 4 4 4 4 3 3
131.20 R IMS 5 5 5 5 5 5 5
131.30 L sc 4 4 4 4 4 2 2
131.70 L sc 4 4 4 4 4 4 4
131.80 L ss 1 1 1 1 1 1 1
132.50 L sc 4 4 9 9 9 9 9
132.60 L sc 4 4 4 4 3 3 3
132.80 R IMS 7 7 7 7 7 7 7
133.70 R sc 4 4 4 2 2 2 2
133.80 L sc 4 2 2 2 2 2 2
133.81 R MSS 6 6 6 6 6 6 6
133.90 R us 1 1 1 1 1 1 1
133.90 L us 1 1 1 1 1 1 1
134.00 L us 1 1 1 1 1 1 1
134.90 R sc 4 4 4 4 4 4 4
135.00 R sc 9 9 9 9 9 9 9
135.00 L MS 10 10 10 10 10 10 10
135.10 R sc 3 3 3 3 3 3 3
135.30 L sc 3 3 3 3 3 3 3
135.50 R sc 9 9 9 9 9 9 9
Habitat Type at Reference Flow SC • Side Channel
IMS • Indistinct Mainstem 55 • Side Slough
MSS • Mainstem Shoal US • Upland Slouah
ISC • Indistinct Side Channel MS • Mainstem
-118 -
River
Mile 23000 18000 16000 12500 10600 9000 7400 5100
135.60 R ss 1 1 1 1 1 1 1
135.70 R ss 1 1 1 1 1 1 1
136.00 L sc 4 4 4 4 4 4 4
136.30 R sc 4 4 2 2 2 2 2
136.90 R us 1 1 1 1 1 1 1
137.20 R sc 4 4 4 4 2 2 2
137.50 R sc 2 2 2 2 2 2 2
137.50 L us 1 1 1 1 1 1 1
137.80 L sc 2 2 2 2 2 2 2
137.90 L sc 2 2 2 2 2 2 2
138.00 L sc 4 4 4 4 4 2 2
138.71 L MSS 6 6 6 6 6 6 6
138.80 R IMS 6 5 5 5 5 5 9
139.00 L us 1 1 1 1 1 1 1
139.01 L MSS 6 6 6 6 6 6 6
139.20 'l IMS 6 6 6 6 6 6 6
139.30 L MSS 6 6 6 6 6 6 6
139.40 L sc 4 4 4 4 4 4 4
139.41 L MSS 6 6 6 6 6 6 6
139.50 R IMS 6 6 6 5 5 7 7
139.60 L MS 10 10 10 10 10 10 4
139.70 R sc 2 2 2 2 2 2 2
139.90 R us 1 1 1 1 1 1 1
140.20 R ss 1 1 1 1 1 1 1
140.40 R IMS 6 6 6 6 6 6 6
140.60 R ISC 6 6 5 8 8 9 9
141.20 R IMS 6 6 6 5 5 5 5
141.30 R IMS 5 5 5 5 5 5 5
141.40 R sc 4 4 4 2 2 2 2
141.60 R ISC 7 7 7 7 7 7 7
142.00 R ISC 5 5 5 5 8 8 8
142.10 R ss 1 1 1 1 1 1 1
142.80 R IMS 6 6 6 6 6 6 6
142.80 L MSS 6 6 6 6 6 6 6
143.00 L MSS 6 6 6 6 6 6 7
143.40 L ss 1 1 1 1 1 9 9
144.00 R MS 10 10 10 10 10 4 4
144.00 M sc 9 9 9 9 9 9 9
144.20 L MS 10 10 10 10 10 10 10
144.40 L sc 2 2 2 2 2 2 2
145.30 R MS 10 10 10 10 10 10 4
145.60 R sc 9 9 9 9 9 9 9
146.60 L ss 1 9 9 9 9 9 9
147.10 L MS 10 10 10 10 10 10 10
148.20 R MSS 6 6 6 9 9 9 9
Habitat Type at Reference Flow SC • Side Channel
IMS • Indistinct Mainstem SS • Sidt Slough
MSS • Mainstem Shoal US • Upland Slough
ISC • Indistinct Side Channel MS • Mainstem
-119 -
APPENDIX 4
APPROXIMATE BREACHING FLOWS
OF SPECIFIC AREAS OF THE MIDDLE SUSITNA RIVER
-120 -
APPENDIX 4
Approximate Breaching Flows of Specific Areas
of the Middle Susitna River
River Breaching Model River Breaching Model
Mile Flow T~2e Mile Flow rne
100.40 R 12500 113.80 R <5100
100.60 R us 113.90 R 7000
100.60 L 9200 114.00 R <5100
100.70 R <5100 114.10 R <5100 DIM
101.20 R 9200 IFG 115.00 R 12000 DIM
101.30 M 9200 115.60 R 22000
101.40 L 22000 RJHAB 116.80 R <5100
101.50 L <5100 IFG 117.00 M 15500
101.60 L 14000 117.10 M 15500
101.70 L 9600 117.20 M 20000
101.71 L MSS DIM 117.70 L <5100
101.80 L 22000 117.80 L 8000
102.00 L 10000 117.90 R 7300
102.20 L us 117.90 L 19500
102.60 L 6500 118.00 L 22000
104.00 R <5100 118.60 M 14000
104.30 M 16500 118.91 L MSS DIM
105.20 R us 119.11 L MSS DIM
105.70 R <5100 119.20 R 10000 IFG
105.81 L MSS DIM 119.30 L 16000
106.30 R 4800 119.40 L us
107.10 L 9600 119.50 L 5000
107.60 L us RJHAB 119.60 L <5100
108.30 L us 119.70L 23000
108.70 L <5100 119.80 L 15500
108.90 L <5100 120.00 R us
109.30 H HSS 120.00 L 12500
109.40 R <5100 121.10 R <5100
109.50 M 16000 121.10 L 7400
110.40 L 12000 121.50 R 19500
110.80 H <5100 121.60 R 15500
111.00 R <5100 121.70 R <5100
111.50 R <5100 121.80 R 22000
111.60 R 11500 121.90 R us
112.40 L 22000 122.40 R 25000
112.50 L us RJHAB 122.50 R 20000
112.60 L <5100 IFG 123.00 L <5100
113.10 R 26000 123.10 R us
J.13. 60 R 10500 123.20 R 22000
113.70 R 24000 RJHAB 123.30 R us
US • Upland Slough HSS • Hainstea Shoal
RJHAB • ADF&G Habitat Hodel DIM • EWT&A Direct Input Hodel
IFG • Instreaa Flow Group
-121 -
River Breaching Model River Breaching Model
Mile Flow Type Mile Flow Type
123.60 R 25500 135.50 R 21000
124.00 M 20000 135.60 R 42000
124.10 L <5100 135.70 R 27500
124.80 R 19500 136.00 L <5100 IFG
125.10 R 20000 136.30 R 13000 IFG
125.20 R <5100 DIM 136.90 R us
125.60 L <5100 137.20 R 104GO
125.60 R 22000 137.50 R 22000 DIM
125.70 R 22000 137.50 L us
125.90 R 26000 137.80 L 20000
126.00 R 33000 IFG 137.90 L 21000
126.30 R 26000 138.00 L 8000
127.00 M <5100 138.71 L MSS DIM
127.10 M <5100 138.80 R 6000
127 .20 M us 139.00 L us
127.40 L <5100 139.01 L MSS DIM
127.50 M <5100 139.20 R <5100
128.30 R <5100 139.30 L MSS
128.40 R 9000 139.40 L <5100
128.50 R 10400 139.41 L MSS IliM
128.70 R 15000 139.50 R 8900
128.80 R 16000 IFG 139.60 L <5100
129.30 L <5100 139.70 R 22000
129.40 R us 139.90 R us
129.50 R <5100 140.20 R 26500
129.80 R <5100 140.40 R <5100
130.20 R 12000 DIM 140.60 R 12000
130.20 L 8200 141.20 R <5100
131.20 R <5100 141.30 R <5100
131.30 L 8000 DIM 141.40 R 11500 IFG
131.70 L 5000 IFG 141.60 R 21000 IFG
131.80 L 26900 142.00 R 10500
132.50 L 14500 142.10 R 23000
132.60 L 10500 IFG, RJHAB 142.80 R <5100
132.80 R 19500 142.80 L <5100
133.70 R 11500 143.00 L 7000
133.80 L 17500 IFG 143.40 L 30000
133.81 R MSS DIM 144.00 R <5100
133.90 R us 144.00 M 22000
133.90 L us 144.20 L <5100
134.00 L us 144.40 L 21000 RJHAB
134.90 R ,5100 IFG 145.30 R <5100
E5.00 R 21500 145.60 R 22000
135.00 L <5100 146.60 L 26500
135.10 R 20000 147.10 L <5100 IFG
135.30 L 18500 148.20 R MSS
US • Upland Slough MSS • Mainstem Shoal
RJHAB • ADF&G Habitat Model DIM • EWT&A Direct Input Model
IFG • Instream Flow Group
-122 -
APPENDIX 5
FISH OBSERVATIONS
-123 -
APPENDIX 5
FISH OBSERVATIONS
All fish observations made during the field reconnaissance are presented
below. Most observations were made late in the spawning season.
Consequently, some of the specific areas may have had spawning activity before
the field investigations took place. There were no fish observed in 58 (34%)
of the 172 specific areas visited during the field work. Fish observations
included an estimate of numbers, species, and life stage (i.e., adult oc
juvenile). In addition, any spawning activity and the number of redds
observed were also recorded.
-124 -
ADULT AND JUVENILE SALMON OBSERVATIONS
HABITAT INVENTORY 8-21-84 THROVGH 10-2-84
RM • River Mile
L • Left Bank Looking Upstream
R • Right Bank Looking Upstream
M • Middle of River (usually island)
* • Spawning Activity Observed As Indicated by the Presence of Redds or
Spawning Behavior.
SPECIFIC
AREA (RM)
100.4R
100.4R
100.5R
100.6R*
100.6R*
100.61
101. 2R*
101.3L
101.41*
101.4L*
101.6L
101.6L*
101. 7L
101.8L*
101. 81*
102.01
102.21*
102.2L*
105.2R
107.1L
107.6L
109.3M
109.5M
110.4L
111.5R
111. 5R
111.6R
DATE
09-11-84
10-02-84
09-11-84
08-22-84
10-02-84
09-11-84
09-11-84
09-11-84
09-10-84
08-22-84
08-22-84
09-10-84
09-10-84
09-10-84
10-02-84
09-10-84
09-10-84
10-02-84
09-10-84
09-10-84
09-1Q-84
09-10-84
09-10-84
08-22-34
09-06-84
10-01-84
09-06-84
OBSERVATIONS
Lots of coho juveniles
One unidentified juvenile in pool (dry channel)
Chum salmon adults
Chum salmon adults, unidentified juveniles, redds
Unidentified juveniles, several redds. scattered
salmon eggs
Pink and chum adults, few unidentifie d juveniles
Twenty+ chum adults and several redds
Two dead chum, 1 dead pink
Coho juvenile (dead), juvenile chinooks
Chum, pink adults, several unidentified juveniles
About 10 chum adults
Spawning chum. adult sockeye, numerous unidentified
juveniles
One adult chum, 1 chum carcass
Hundreds of juvenile (coho), 3 adult sockeye, 3 adult
chum
Lots of unidentified juvenile salmonids
One unidentified juvenile salmonid, 2 unidentified
carcasses
Thousands of salmonid juveniles (identified 2 coho and
1 sockeye
Hun.dreds of unidentified salmonid juveniles, 15 redds,
1 sockeye adult, 2 chum adults, 1 dead pink
Few juveni les (chino, coho)
Chum and p i nk carcasses
One pink carcass. several juveniles (2 identified as
coho)
One chum carcass
One chum carcass
One chum adulr.. ! chum carcass
Several chum carcasses, couple of unidentified
juveniles
Several chum carcasses, lots of unidentified juveniles
Three chum carcasses
.. 125 -
SPECIFIC
AREA (RM}
112.5L
112. SL
112. SL
112. 6L
112.6L
113. 6R
113. 7R*
113. 7R*
113. 7R*
114.0R
114 .1R
115.0R*
115.0R*
115. OR*
115. 6R*
116.3R
117 .OM
117 .1M
117 .1M
117 .2M
117 .85L
117. 9R
117. 9L*
118.91L*
119.11L*
119. 2R
119. 3L*
119.4L
119.4L*
119.5L
119. 7L
120.0L
120.0R*
121.1L*
121.5R
121.6R
121.7R
121.8R*
121.8R*
121. 9R*
DATE
09-06-84
09-06-84
08-22-84
09-06-84
09-11-84
09-06-84
09-06-84
08-22-84
09-11-84
09-06-84
09-06-84
09-06-84
08-22-84
09-06-84
09-06-84
09-06-84
09-06-84
09-06-84
08-22-84
09-06-84
10-Q1-84
09-06-84
09-06-84
09-07-84
09-07-84
09-07-84
09-07-84
09-07-84
08-22-84
09-07-84
09-07-84
09-07-84
09-07-84
09-07-84
09-07-84
09-07-84
09-07-84
08-22-84
09-07-84
09-07-84
OBSERVATIONS
Several unidentified juveniles
Thousands of juveniles unidentified
Unidentified juveniles
Several juvenile chinook
Juvenile salmonids -unidentified
Chum and pink carcasses - 1 juvenile unidentified
About 40 adult chua. lots of juveniles (chinook and
coho)
About 50 adult chum
Greater than 20 adult chua. redds. juvenile chinook.
coho. sockeye
Chum carcasses. 1 adult chum. chinook juvenile (1)
One chua carcass
Fourteen+ adult chums. 1 sockeye adult. 1 unidentified
juvenile
Several adult chums
Several chinook juveniles. 1 rainbow juvenile
Sixty+ adult chum. several chinook juveniles. 1 rain-
bow juvenile
One chum carcass. several unidentified juveniles
Several chum carcasses
Chinook juveniles
Several unidentified juveniles
Scattered eggs
Chinook and coho juveniles
Adult coho (in tributary). chum carcass. unidentified
juveniles
Two coho juveniles
About 16 chum adults
About 6 chum adults. 3 redds
Several unidentified juveniles
Two chum adults. chinook and sockeye juveniles.
1 grayling
A few unidentified juveniles
Redds
Several chinook juveniles and unidentified
Coho juveniles
Unidentifi~d juveniles
One redd observed
One chum adult. 2 unidentified juveniles
Chinook juveniles
Chinook juveniles
Chum adults. chinook juveniles
Chum adults. unidentified juveniles
Greater than 40 chum adults
One chum carcass. chinook juvenile. obvious spawning
activity
-126 -
SPECIFIC
AREA (RM)
122.4R*
122.5R*
122.5R*
123.1R
123.1R
123.2R
l23.3R
123.6R*
123.6R*
124.0H
125.1R
l25.1R
125.2R
125.9R*
125.9R*
126.0R*
126.0R*
l26.3R*
127.0L
127.4L
127.5H
128.3R
128.5R
128.7R*
128.8R*
128.8R*
129.4R*
129.5R
129.5R
130.2R*
130.2L*
131. 3L*
131.7L*
131.8L*
132.6L
132.8R*
133.7R*
133.7R*
133.8R
133.8L
133.8L
133.9R*
133.9L*
DATE
09-07-84
09-07-84
Cb-21-84
09-07-84
09-30-84
09-07-84
09-30-84
08-21-84
09-07-84
09-07-84
09-05-84
09-05-84
09-05-84
08-21-84
09-05-84
09-05-84
08-21-84
08-05':"'84
09-05-84
09-05-84
09-05-84
09-05-84
09-05-84
09-05-84
08-21-84
09-05-84
09-05-84
09-05-84
09-30-84
09-05-84
09-05-84
09-05-84
09-04-84
C9-04-84
09-05-84
09-05-84
08-21-84
09-04-84
09-04-84
08-21-84
09-05-84
09-04-84
09-04-84
OBSERVATIONS
Several chum adults, several redds, coho juvenile
About 150 chum adults, unidentified juveniles, chinook
juvenile
Chum adults
Several unidentified juveniles
Many unidentified juveniles
Several chinook and coho juveniles, 1 grayling juvenile
One unidentified juvenile
Sockeye and chum adults
Chum adults, chinook and coho juveniles
Several chinook juveniles
Two chum carcasses
Several unidentified juveniles
One chum adult, few unidentified juveniles
Few sockeye adults, 75+ chum adults, school of
unidentified juveniles
Sockeye and chum adults
Sockeye and chum adults, several unidentified juveniles
Some sockeye adults, few pink adults, hundreds of chum
adults
Sockeye and chum adults
One chum carcass, several unidentified juveniles
Several unidentified juveniles
One chum carcass
One chum, chinook juveniles
Chinook juveniles
Chum adults
Several adult chums
Several unidentified juveniles
Several chum adults, unidentified juveniles
Chum adults
One coho carcass
Chum adults, chinook juveniles
One chum carcass, unidentified juveniles (1 chinook
identified)
Chum adults, redds
Lots of chum adults, few unidentified juveniles
About 20 chum adults, lots of redds, 1 unidentified
juvenile
Unidentified juveniles
Chum adults, 1 dead chinook juvenile
Some chum adults
Chum adults, few chinook juveniles
Chum adults, 1 unidentified juvenile
Chum adult
Chinook juveniles
Chinook juveniles
Chum adults, chinook juveniles
-127 -
SPECIFIC
AREA (RM) DATE
134.01 09-04-84
134.9R* 08-21-84
134.9R* 09-04-84
135.01* 09-04-84
135.1R 09-04-84
135.6R* 09-04-84
135.6R* 08-21-84
135.7R 08-21-84
136.01 09-04-84
136.3R* 09-04-84
137 .2R* 09-04-84
137 .5R 09-04-84
137.51 09-04-84
137.91 08-21-84
138. 7L 09-04-84
139.011* 09-04-84
139.01* 08-21-84
139.41 09-03-84
139.5R 09-03-84
139.61 09-03-84
139.9R* 09-03-84
140.2R* 08-21-84
140.2R* 09-03-84
140.6R* 09-03-84
141.4R* 09-03-84
141.6R* 08-21-84
142.0R 09-03-84
142.0R 09-29-84
142.1R* 09-03-84
142.81* 09-03-84
143.01* 09-03-84
143.41* 09-03-84
144.21 09-03-84
144.41* 08-21-84
145.6R 08-21-84
33RD4/016
OBSERVATIONS
One chum carcass, few unidentified juveniles
One chum adult , 1 chum carcass
Several chum adults, several unidentified juveniles
Chinook and unidentified juveniles
Several unidentified juveniles
Hundreds of sockeye adults, thousands of chum adults,
chinook juveniles
Sockeye, chum, pink adults greater than 400 fish
Some chum adults, 2 pink carcasses, several
unidentified juveniles (1 chinook)
Two chum carcasses, unidentified adults
Chum adults, chinook juveniles
Chum adults, 2 unidentified juveniles
Chum adults, 2 chum carcasses, chinook juveniles
Chum carcasses, chinook juveniles
Few unidentified juveniles
One chum carcass, 1 unidentified adult
About 30 chum adults
Some sockeye adults, 50+ chum adults, 1 pink carcass
Several chum carcasses, several unidentified juven iles
(1 chinook identified)
Sockeye and chum adults
Several chum carcasses, several unidentified juveniles
(1 chinook identified)
Sockeye and chum adults, chinook juveniles
Lots of chum adults, lots of unidentified juveniles
About 12 chum adults , lots of coho and chinook
juveniles
Several chum carcasses, redds, few unidentified adults
(1 chinook identified)
Hundreds to thousands of sockeye and c num adults,
chinook juveniles
Some sockeye adults, hundreds of chum adults,
1 unidentified juvenile
Chum adults, unidentified juveniles
Fifteen+ unidentified juvenile fish
Sockeye and chum adults, greater than 500 chinook
juveniles, several unidentified juveniles
Fifty+ chum adults
Twelve+ chum adults, unidentified juv eniles
Thirty-two+ chum adults, unidentified juven iles
(1 chinook identified)
Chum carcass. chinook juveniles
Fifty+ chum adults
One chinook juvenile
-128 -