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APPENDIX A
EVALUATION OF TAILRACE ATTRACTION
FOR THE PROPOSED
BRADLEY LAKE HYDROELECTRIC PROJECT
WOODWARD-CLYDE CONSULTANTS
JANUARY 1985
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APPENDIX A
EVALUATION OF TAILRACE ATTRACTION
FOR THE PROPOSED
BRADLEY LAKE HYDROELECTRIC PROJECT
WOODWARD-CLYDE CONSULTANTS
JANUARY 1985
TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Objective 1
1.3 Report Organization 2
2.0 PHYSICAL FEATURES OF THE PROJECT AREA 2
2.1 Bradley Lake 2
2.2 Bradley River 3
2.3 Kachemalt Bay 3
3.0 PROJECT DESCRIPTION 4
3.1 Project Facilities 4
3.2 Project Operation 5
4.0 FISH RESOURCES OF THE BRADLEY RIVER 5
4.1 Species Occurrence 5
4.2 Salmon Spawning Habitat Utilization 5
4.3 Salmon Production 7
5.0 PINK SALMON BIOLOGY 8
5.1 Life History Summary 8
5.2 Salmonid Homing Behavior and Imprinting 10
5.3 Pink Salmon Straying 12
6.0 PHYSICAL CHARACTERISTICS OF TAILRACE 14
6.1 Discharge 15
6.2 Salinity 15
6.3 Substrate and Sedimentation 17
6.4 Water Temperatures 18
7.0 ANTICIPATED IMPACTS 18
7.1 Attraction 18
7.2 Spawning Delays 20
7.3 Spawning and Incubation Conditions 21
8.0 MITIGATION OPTIONS 24
8.1 Approach 24
8.2 Selection of Evaluation Species 26
8.3 Avoidance and/or Minimization Measures 26
8.4 Rectification 31
8.5 Compensation 32
9.0 AGENCY CONSULTATION 33
10.0 LITERATURE CITED 34
i
LIST OF FIGURES
Figure 1. Project Location
Figure 2. Physical Features of Project Area
Figure 3. Project Facilities
Figure 4. Phenology Chart for Salmonids Known to Inhabit
Bradley River.
Figure 5. Salinity Duration Curves for 10 and 25 ppt Bay
Salinity.
Figure 6. Layout of Seton Cree~ Hydroelectric Project.
Figure 7. Comparison of Tailrace Cross Section with
Riffle Reach Cross Section.
Figure 8. Mitigation Option Analysis.
iii
1.0 INTRODUCTION
1.1 Background
The proposed Bradley Lake Hydroelectric Power Facility is to be
located on the Kenai Peninsula at the head of Kachemak Bay, about 105
miles south of Anchorage, Alaska (Figure 1). Water is to be withdrawn
from Bradley Lake and conveyed via tunnel to a powerhouse at
tidewater. This diversion would alter the natural flows of the
Bradley River.
The Bradley River receives at least limited use by five species of
Pacific salmon. Relatively small numbers of pink salmon (Oncorhynchus
gorbuscha) and a few coho (fh. ltisutch) and chum salmon (fh. keta) spawn
in the Bradley River drainage. Indication of use by other salmon
species is restricted to observ~tion of several spawning pairs (USFWS
1982 and Alaska Power Authority 1983). In comparison to other
Kachemak Bay drainages, it is not considered to be highly productive.
In part, this is likely caused by large natural variations in flows
between spawning and incubation periods in the Bradley River. Under
Project operation, the stabilization of flow regimes in the lower
Bradley River should improve fish production in the system. The
Bradley River Instream Flow Studies (Alaska Power Authority 1983)
predict a significant increase in effective spawning habitat, since it
is estimated that under project conditions almost all spawning habitat
will remain wetted by winter flows.
There is concern, however, that during Project operation, returning
adult salmon will be attracted to the tailrace where successful
spawning is unlikely. This report addresses that topic and is based
on a review of avialable literature and an evaluation of the fishery
resources and physical conditions in the Project area.
1.2 Objective
The purpose of this report is to provide an evaluation of the
potential impacts resulting from tailrace operation and to identify
1
2.2 Bradley River
he Bradley River ffows from the lake through a steep, narrow canyon
for much of its 10-mile length before reaching Kachemalc. Bay. The
lower reach of the river, which carries a high suspended sediment
load, emerges from the canyon through a series of rapids and falls
(RM 5.9), flattens in gradient, and crosses extensive tidal flats to
enter Kachemak Bay. The Bradley River below RM 4. 3 is heavily
influenced by tidal action and experiences frequent seawater
intrusion, backwater effects, and sediment deposition (Alaska Power
Authority 1983).
Approximately 90 percent of the annual discharge in the Bradley River
occurs during the period of May through October. The highest flows
usually occur during the late summer when glacial melt is most rapid
and precipitation rates are high. The mean annual discharge at the
river mouth has been estimated to be 598 cfs, with mean monthly
discharges ranging from 80 cfs in March to 1,541 cfs in July (R&M
Consultants 1983). The Bradley River contributes about 25 percent of
the annual surface freshwater inflow to Kachemalc. Bay.
2.3 Kachemak Bay
Kachemak Bay is a narrow, tapered, northeasterly extension of Lower
Cook Inlet that extends about 30 miles into the southwest coast of the
Kenai Peninsula. The head of the bay consists of extensive mud flats
that are alternately covered and exposed by high and low tides. Tides
are a major influence in the bay, having a maximum range exceeding
2 7 f t and a daily range of at least 11 f t, as measured at Seldovia
near the mouth of the bay. Five major contributors (the Bradley, Fox
and Martin rivers, Sheep Creek and Battle Creek) provide substantial
summer input of freshwater at the head of Kachemalc. Bay, however this
influence is much reduced during winter (Colonell 1980). Tidal
activity affects the rapid mixing of fresh and oceanic water in the
upper bay. At low tide fresh riverine water, partially of Bradley
River origin, accumulates along the southern shore. However, flood
3
3.2 Project Operation
Under Project operation, flow in the Bradley River will be regulated
throughout the year in accordance with the instream flow requirements.
Regulation of the river flow will result in significant flow
reductions, particularly during the summer months, and stabilized
flows during winter. During the salmon spawning period
(June-October), flows in the Bradley River would be reduced by 83 to
93 percent (Table 1).
Discharge from the powerhouse tailrace will range from 439 to 1, 250
cfs and will average 497 cfs, which will be four to five times that of
the river. The reduction in Bradley River flows and the establishment
of a substantial tailrace outflow may divert returning salmon to the
tailrace.
4.0 FISH RESOURCES OF THE BRADLEY RIVER
4.1 Species Occurrence
Fifteen species of fish, including five species of Pacific salmon, are
known to occur in the Bradley River drainage (Table 2) • These fish
are confined to the lower portion of the river because a waterfall at
RM 5.9 precludes further migration upstream.
Relatively small numbers of pink salmon, and a few coho and chum
salmon spawn in the Bradley River system. Although a limited number
of adults of both sockeye and chinook salmon and a few juvenile
chinook salmon have been observed in the Bradley River, there is no
evidence of significant reproducing populations for either species
(USFWS 1982 and Alaska Power Authority 1983). The phenology of
salmonids known to inhabit the Bradley River is shown in Figure 4.
4.2 Salmon Spawning Habitat Utilization
The availability of suitable pink salmon spawning habitat in the
Bradley River mainstem is restricted to a small portion of the
5
Chinook salmon generally spawn near riffles of large rivers or large
tributaries. They tend to use deeper water and larger gravels than
other salmon species (Scott and Crossman 1973). Chinook salmon enter
and spawn in the Bradley River in apparently low numbers during July
and August (USF'WS 1982). Six adult chinook salmon, in spawning and
spent condition, were encountered in Bear Island Slough (RM 5.1)
during early August 1983 (Alaska Power Authority 1983).
Depending upon habitat availability, sockeye salmon spawning locations
include lake shores, tributaries, or spring-fed side channels along
streams (McPhail and Lindsey 1970, Bechtel 1983, ADF&G 1983a).
Although sockeye salmon have been found in the Bradley River, no
spawning has been documented. Even though an appreciable number of
fish enter the system, it is likely that those fish have strayed from
their natal streams and are merely holding in the Bradley River for a
temporary period (USFWS 1982). Tag and recapture efforts suggest that
the fish eventually enter other streams to spawn (T. Schroeder, ADF&G,
pers. comm., 1983).
4.3 Salmon Production
The following discussion is focused on pink salmon because of the
insignificant contributions of the other four salmon species.
However, any program or mitigation measures directed towards pink
salmon are likely to be effective for other species using mainstem
habitats.
Relative to other Kachemak Bay drainages, the Bradley River system is
not considered to be highly productive. This is well illustrated by
comparison to pink salmon escapements in several index waterbodies in
the southern district of the ADF&G Lower Cook Inlet Management Area
(Table 3). The average pink salmon escapement (1951-1982) of Humpy
Creek, a smaller stream system some ten miles southwest of the Bradley
River, is approximately 50,000 fish or roughly 50 times that of the
estimated Bradley River pink salmon escapement in 1983. An even
7
depending largely upon location. The eggs are deposited in gravel
redds generally in the lower sections of coastal streams; however,
some fish may move as much as 300 miles upstream in larger rivers.
Both tidally and non-tidally influenced stream reaches may be used for
spawning (Scott and Crossman 1973). Intertidal spawning is typical of
pink salmon populations within Prince William Sound and southeast
Alaska (Helle, Williamson and Bailey 1964).
A female pink salmon may carry 800 to 2000 eggs, depending upon the
size of the fish, location, and year; may construct several redds; and
may spawn with different males. Both sexes die soon after spawning.
The eggs usually hatch between December and February, depending upon
water temperature, with warmer water accelerating development (Bailey
and Evans 1971). The alevins (newly hatched fish with an attached
yolk-sac) remain in the redd gravels for several weeks before emerging
in the spring (usually in April or May), when development is complete
(Scott and Crossman 1973). Upon emergence the fry (young-of-the-year)
immediately begin downstream migrations to the sea (Neave 1966). Upon
leaving their natal streams, pink salmon fry probably remain inshore
throughout their first summer, but then migrate to the open sea.
During their oceanic life Alaskan pink salmon may be found in most of
the Northeast Pacific, the Bering Strait southwest to the Aleutians,
and southeasterly to the California coast (Hart 1973). After spending
some 15 to 18 months in the sea, the adults return to their natal
streams to spawn. Returning pink salmon are generally 17 to 19 inches
in length and most are 2 to 7 pounds in weight.
The two-year life cycle of the pink salmon results in two genetically
distinct populations because each year class is temporally (and
therefore reproductively) separated from the next. The two
populations are referred to as odd-year or even-year runs, based on
the year the fish spawn. Fish abundance varies between odd and even
years. One run is typically smaller than the other and may even be
non-existent in some locations.
9
,...
Homing behavior in salmon is connected, at least in part, to a period
of rapid, irreversible learning that takes place at the natal site or
smolting site during the fishes 1 early life history prior to its
seaward migration. Hasler and Wisby (1951) and other investigators
(Brett and Groot 1963; Harden-Jones 1968 and Mayr 1974) have termed
this behavior "imprinting". It is theorized that during the
imprinting period, salmon learn the cues that enable them to identify
their home stream. Later, as adults during the spawning migration,
they remember those cues to locate the home stream once again.
Experiments in which young salmon are transplanted to other waters to
develop have helped define the imprinting period (i.e., prior to
smoltification) and have shown that although there is a genetic
component to homing behavior, memory of the home stream is not
directly inherited. When presmolt salmon are transplanted to other
waters, as adults they return to the site of release--not to the
parent stream (Donaldson and Allen 1957; Carlin 1968; Jensen and
Duncan 1971; Vreeland et al. 1975; and Bams 1976).
Extensive studies involving artificial imprinting (i.e., young fish
are subjected to a synthetic odor and later, as migrating adults, they
are decoyed to a simulated home-stream scented with this odor) have
been conducted to further elucidate homing mechanisms (Hasler and
Scholz 1983). In the most elaborate of these studies, hatchery stocks
of coho salmon were artificially imprinted with either morpholene
(C 4H9NO) or phenethyl alcohol (PEA) (C 8H10 o) at smoltification,
marked, and released into Lake Michigan along with a control group of
fish that was marked but not exposed to either chemical. During the
spawning period 18 months later, two home-streams were simulated by
metering morpholine or PEA into the water and were then surveyed for
marked fish. Additionally, 17 other stream locations were surveyed to
determine whether a significant proportion of experimental fish were
entering non-scented streams. The artificial imprinting was conducted
twice: in 1973 with 5,000 fish in each group, and again in 1974 with
10,000 fish per group. Spawning migrations were in 1974 and 1975,
respectively. Total fish recoveries from both experiments included
681 morpholine-imprinted fish (recovery rate =-4. 5 percent), 362
11
6.1 Discharge
Tailrace flows are projected to be between 450 to 500 cfs on an
average basis ranging from minimum values of 440 cfs to maximum values
of 1250 cfs during operation. Table 4 presents projected average
monthly tailrace flows. Flow interruptions will take place as part of
normal Project operations, and possibly for periods exceeding 24 hours
during annual maintenance and shutdowns.
Velocities in the tailrace were calculated based on average cross-
section and shape. The cross-sectional slope was assumed to be
trapezoidal with 2:1 side slopes and a 70 ft bottom width. Average
cross-sectional velocities in the lined portion of the tailrace are
expected to range from 3.0 to 4.5 fps for the range of tailrace flows
expected under operation. At discharges of 450 cfs average
cross-section velocity is 3.0 fps. Depths are expected to range from
2 ft at 450 cfs to 3.5 ft at 1250 cfs.
Depth and velocity cannot be computed for the unlined portion of the
channel as channel cross-sectional shape is unknown. Tailrace
discharge is expected to excavate a channel through the silt deposits
of the tidal flats. This channel will probably be wider and shallower
than the lined portion of the tailrace. Thus velocities would be
lower than those forecast for the lined portion.
6.2 Salinity
The salinity in the Bradley Lake tailrace was estimated based on the
proposed tailrace channel dimensions and flow releases of 450 cfs.
The salinity of Kachemak Bay in the vicinity of the tailrace varies
significantly by location and season; thus several different values
were used to calculate estimated salinities.
Normal depth of flow in the tailrace will be about 2 ft for a
discharge of 450 cfs. Based on a trapezoidal tailrace cross section
with 2:1 side slopes and a 70 ft bottom width, the volume of fresh
water (Vf) at normal depth is 148 ft 3 /ft of channel.
15
salinity patterns in upper Ka.chemak Bay (APA 1984). At flows of
approximately 1200 cfs in the Bradley River (average summer flows)
salinities measured near Sheep Point ranged from 1. 5 ppt to 7 ppt
(Alaska Power Authority 1983 and Colonell 1980). Thus tailrace
salinities of 0 to 8.6 ppt computed at bay salinities of 5 ppt may be
considered representative of summer conditions (Table 5).
Because freshwater inflow from the Sheep and Fox rivers would be
greatly reduced, even with the Project, the winter salinities in
Kachemak Bay are forecast to be higher. Salinities in upper Kachemak
Bay are expected to be approximately 25 ppt. Salinities measured near
Sheep Point in March ranged from 23.5 to 27.3 ppt (Colonell 1980) •
Winter tailrace salinities are forecast to range from 0 to 21.9 ppt
(Table 5).
6.3 Substrate and Sedimentation
Substrate in the unlined portion of the tailrace is expected to
consist of sands grading to silts. and sands similar to substrates
associated with other intertidal channels in upper Kachemak Bay.
Entrapment of silts and sands in the small gravel results from tidal
interactions.
Sedimentation of tailrace substrate is expected to occur as a result
of tidal inundation. Upper Kachemak Bay receives significant inflow
from glacial rivers and consequently contains a large amount of
suspended glacial sediment. Substrates in tidally influenced channels
in upper Kachemak Bay are composed of fine silts and sands. The
sediment regime is related to two processes associated with tidal
action. The incoming tide carries sediments from the bay upstream
into the stream channels and deposits them at slack tide. In
addition, the stream or river is carrying sediments downstream and
these sediments are deposited when the tidal backwater is encountered.
In the tailrace, tidal borne sediments are expected to be deposited
over the spawning gravels. Although the streamflow in the tailrace
during low tide may be sufficient to remove some of the silts and fine
17
tailrace have been estimated to range from 3.0 to 4.5 cfs under low
tide conditions. During high tide cycles the incoming tidal waters
will essentially dam the tailrace and velocities will approach zero.
Thus, on the average it is likely that tailrace discharges may be of
sufficient velocities to attract returning fish roughly 50 percent of
the time. Similar problems have been encountered elsewhere at other
hydroelectric power facilities.
The Puntledge River Hydroelectric Facility on Vancouver Island, B.C.,
is in the upper reaches of the river, some 15 miles above Comox Bay.
Flows of 1000 cfs are diverted from the river and discharged some four
miles downstream. Residual flow in the river is 100-200 cfs.
Discharge of the diverted flow back into the river resulted in the
attraction and accumulation of salmon in the powerhouse tailrace
(Andrew and Geen 1960).
In a similar situation, pink salmon were attracted to the tailrace of
the Seton Creek Hydroelectric facility at Lillooet, B.C. This
facility, as depicted in Figure 6, is located well upstream (200 mi)
on the Fraser River. Returning pink salmon bound for Seton Creek must
pass the powerhouse tailrace which discharges directly into the Fraser
River, approximately one mile downstream from the confluence of Seton
Creek. Powerhouse flow is diverted out of Seton Lake. Flow in Seton
Creek is from Seton Lake releases and Cayoosh Creek. Tailrace flows
(4000 cfs) are approximately 10 times greater than the residual flows
in Seton Creek. Pink salmon were attracted to and entered the
tailrace where they remained an average of one day, although some were
there longer. Maximum counts in the tailrace suggest that about 4500
fish (or about 7.5 percent of the population) occurred in the tailrace
during the peak of the run.
Spawning migrations into Segon Creek typically showed a daily morning
peak in abundance. During days of continuous powerhouse operation
such a peak was not evident and the number of fish entering the stream
was markedly reduced (Andrew and Geen 1958). Scheduled plant
shutdowns were conducted to mitigate the impacts resulting from
19
.-
extended periods and the ability of those fish to reach Seton Creel<
and spawn effectively was likely impaired. The overall magnitude of
this impact was not assessed (Andrew and Geen 1960).
Although flow conditions in the Bradley Lake tailrace may temporarily
attract returning salmon, the conditions there are not ammenable to
spawning (i.e. lack of suitable substrate and increased salinities).
The opportunistic nature of the species would likely cause them to
seek other areas in which to spawn. The short distance to the
spawning grounds (5 miles) and relatively flat gradient of the Bradley
River would not present a formidable migratory route. Thus, it is
anticipated that even if temporarily delayed, significant reductions
in pink salmon production would not occur.
7.3 Spawning and Incubation Conditions
Poor water quality conditions in the tailrace would probably preclude
incubation if spawning activity occurred there. The elevation of the
proposed tailrace is approximately equal to sea level which would
subject any developing embryos in the tailrace area to saline
conditions 50 percent of the time. In general, the literature
indicate that survival of embryos is satisfactory in the upper third
of the intertidal zone and poor to non-existent in the lower levels.
Estimations of salinities and inundation times in the tailrace area,
which occurs in the middle of .the Kachemak Bay intertidal zone would
most likely result in marginal incubation conditions. Other factors
such as sedimentation may result in additional, if not complete,
mortality to embryos.
For comparative purposes, a cross section from Riffle Reach, the
lowest location of successful spawning in the Bradley River, and the
tailrace cross section are plotted in Figure 7. The tailrace water
level is substantially lower in elevation, implying that the
conditions responsible for the lack of spawning below Riffle Reach
most likely also prevail in the tailrace area.
21
to cause extensive delays in migration or loss of reproductive success
for pink salmon. However, if a significant attraction problem should
result, mitigation activities will be undertaken. The Alaska Power
Authority will provide monit.oring activities at the tailrace to
determine the extent and duration of the attraction.
Various mitigation options have been instituted at other water
development projects with attractant flows and several of these
options have been suggested for use in the Bradley River. This
section presents an evaluation of the feasibility and applicability of
several of the available options to the Bradley Lake Hydroelectric
Project tailrace. If mitigation is required, this analysis will
assist in selection of appropriate mitigation measures. These options
are presented in a fashion consistent with the hierarchical approach
presented in Alaska Power Authority mitigation Fish and Wildlife
Mitigation Policy established by the Alaska Power Authority and
coordinating agencies (~A 1982) as well as mitigation policies of
U.S. Fish and Wildlife Service (1981) and ADF&G (1982). The
hierarchical scheme is shown in Figure 8.
Mitigation options proposed are grouped into two broad categories
based on different approaches:
Modifications to design, construction, or operation of the
project
Resource management strategies
The first approach is project specific and emphasizes measures that
avoid or minimize adverse impacts according to policies established by
the resource agencies (ADF&G 1982, USFWS 1981). These measures
involve adjusting or adding project features during design and
planning so that mitigation becomes a built-in component of project
actions.
25
temporary shutdowns allow the fish an opportunity to leave the
tailrace and find their natal streams.
Flow interruption has been used to successfully pass pink salmon at
Seton Creek Hydroelectric Facility on the Fraser River system in
Canada (Andrew and Geen 1958). Pink salmon were attracted to and
entered the tailrace. Complete plant shut-downs for 3 hours a day on
Sundays, Tuesdays and Thursdays resulted in most fish leaving the
tailrace and resuming their upstream migration.
Plant shut-down resulted in peak migration counts 2 hours later at the
stream. Other partial shut-downs did not cause fish to leave the
tailrace.
Should a significant number of returning adult salmon accumulate at
the Bradley Lake tailrace, it is anticipated that temporary plant
shut-downs may alleviate potential impacts to the fish by allowing
them to continue their upstream migrations. Four hour shutdowns timed
to occur with the last two hours of the ebbing tide and the first two
hours of the incoming tide should initiate movement of the fish into
the estuary. There, they would encounter the outflow from the Bradley
River, Fox River and Sheep Creek (under Project conditions this
combined flow would range between 3,065 and 3,842 cfs during
June-September) and would likely move upstream past the tailrace.
8.3.2 Chemical Attractants
Artificial imprinting with chemicals such as morpholine has been used
to investigate the homing response of salmonids. Experimental
evidence indicates that it is possible, at least in part, to direct
the final stages of the spawning migration in some species (Scholz et
al. 1975). However, almost all work to date has been done with
hatchery stocks under relatively controlled imprinting conditions
(Section 5. 3). Hassler and Kukas (1982) reported on the successful
recovery of a small number of artificially imprinted coho and chinook
salmon at the ~lad River hatchery in California. That facility is
27
Section 5.3, the time of imprinting in pink salmon is not known. It
may occur while the fish is developing in the redd, while it is
migrating downstream, or even while it is residing in the estuary,
prior to moving offshore. In lieu of information to the contrary,
morpholine would have to be applied almost throughout the entire
incubation phase (i.e., December-April) to ensure that young were
exposed to the chemical at the proper time. Furthermore, delivery of
adequate concentrations of morpholine throughout the mainstem is
likely to present considerable design and logistic difficulties. To
attract the returning adults, morpholine would have to be added to
mainstem waters from June through September. Thus at a minimum,
morpholine would have to be applied nine months of the year to effect
imprinting and/or return.
It is doubtful that such a program could be effectively implemented
without significant increased knowledge of · the imprinting process in
pink salmon. Thus, it is unlikely that this is a viable mitigation
option for the Bradley Lake Project, particularly when it has failed
with pink salmon experimentally (W. Heard, NMFS, pers. comm. 1984).
8.3.3 Chemical Repellents
Brett and McKinnon (1952) found that Pacific salmon halted upstream
migratory movements when exposed to water in which human hands had
been rinsed. Subsequent work (Idler et al. 1956, 1961) identified the
amino acid, L-serine, as the component in hand rinse which had
repellent qualities. Migrating salmon exhibited an immediate alarm
reaction and fled downstream when exposed to dilute concentrations of
L-serine. Pink salmon can detect amino acid solutions at
-5 concentrations of 10 M and exhibit avoidance responses to L-serine,
as well as alanine and valine (Shparkovskiy et al. 1981). A single
introduction of L-serine may cause avoidance up to 20 minutes (Bell
1980).
Accounts are lacking as to the general applicability of the use of
repellants under continuous field conditions. It may be possible to
29
fish passage (Bell 1980). For them to operate effectively on adult
salmon they must be established in flows of at least 3 fps and need to
be configured to provide sufficient depth of field (i.e., voltage
gradient of 0.3 to 0. 7 volts/inch) so as to allow the fish to sense
the current without becoming totally immobilized (Burrows 1957).
Owing to the tidal flux and salinities in the estuary it is unlikely
that an electrical weir would function at the Bradley Lake tailrace
except during periods of low tide. Only at that time would flows
(i.e., Q _3 fps) and salinity (i.e. 0/00) be ammenable to the use of
an electrical weir in the channel. However, since the weir cannot be
operated continuously, fish entering during high tides would be
trapped above the weir with no way to escape. Furthermore, placement
of a weir in the tailrace channel would only block access to the upper
portion of the tailrace and would not deter fish from gathering just
downstream. This option therefore is not considered feasible for the
Bradley Lake Project.
8.3.6 Discharge Pipe and Diffuser System
Use of a discharge pipe and diffuser system at tailrace outfalls can
dissipate the effects of flow. At the Bradley Lake Project, however,
incorporation of such a design would require the proposed turbine-type
powerhouse and tailrace arrangement to be drastically changed. Some
of the available pressure head would be used to pass the necessary
flows (1270 cfs) through the discharge pipe and diffuser system
extending below low tide. The low tide line is about 9000 ft away
from the powerhouse. Therefore, there are high construction costs,
plus costs associated with lost energy due to lost pressure head. The
costs of this option are prohibitive.
8.4 Rectification
8.4.1 Transport of Fish
It is possible to provide trapping facilities for trapping adult
salmon from the powerhouse tailrace; however, it does not appear to be
31
9.0 AGENCY CONSULTATION
J. Bailey, 1984. Telephone conversation regarding pink salmon straying
and effect of barriers. National Marine Fisheries Service, Auke
Bay Fisheries Laboratory. P.O. Box 210155, Auke Bay, Alaska 94821.
R. Blackett~ 1984. Pink salmon straying. Alaska Dept. of Fish and
Game, Fisheries Rehabilitation Enhancement and Development, P. 0.
Box 686, Kodiak, Alaska 99615.
E. Brandon, 1984. Use of morpholene on coho and chinook salmon,
possible mitigation through plant operation. University of
Washington, School of Fisheries WH-O, Seattle, Washington 98195.
N. Dudiak, 1984. Morphiline use on king salmon in Homer, and pink
salmon straying in Halibut Cove and Tutka Lagoon. Alaska Dept.
of Fish and Game, Fisheries Rehabilitation and Enhancement
Division, P.O. Box 234, Homer, Alaska 99603.
T. Hassler, 1984. The use of morpholene on coho and chinook salmon at
the Mad River Hatchery. Humboldt State University. California
Cooperative Fishery Research Unit, Humboldt State University, Arcata,
California 95521.
B. Hauser, 1984. Morphiline use on king salmon. Alaska Dept. of Fish
and Game, Fisheries Rehabilitation Enhancement and Development,
333 Raspberry Road, Anchorage, Alaska 99502.
w. Heard, 1984. An unpublished report on pink salmon life history and
studies. Included straying, barriers and imprinting. National
Marine Fisheries Service, Auke Bay Fisheries Laboratory, P.O. Box
210155, Auke Bay, Alaska 94821.
M. Kelly, 1984. Returns of chum and pink salmon to Tyee Creek and
tailrace. AEIDC, 707 A Street, Anchorage, Alaska 99501.
J. Larin, 1984. The use of morpho lene on coho salmon. Effects of
barriers on pink salmon behavior. Oregon State University.
College of Agricultural Science, Fisheries and Wildlife,
Corvalis, Oregon 97330.
A. Lil, 1984. Effect of M.cSeaton Lake tailrace on sockeye salmon.
Fisheries and Oceans, West Pender Street, Vancouver B.C., V6E 2Pl.
T. McDaniel,, 1984. Straying and the effect of barriers on pink
salmon. Alaska Dept. of Fish and Game, Fisheries Rehabilitation
Enhancement and Development, Cordova, Alaska, 99574.
A. Palmaisano, 1984. Electric weir parameters and usage.
and Wildlife Service. Marrowstone Field Station,
Fishery Research Center, Nordland, Washington 98358.
U.S. Fish
National
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33
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35
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39
APPENDIX A
TABLES
Minimum Expected
Project Project Existing Percent
Month Flow (cfs) Flow (cfs) Flow (cfs) Change
June 100 174 1043 -83
July 100 102 1322 -92
August 100 100 1379 -93
September 75a 75 8 1081 -93
~nimum project flow of 75 cfs represents average of 100 cfs from
September 1-15 and 50 cfs from September 16-30.
EXISTING AND POST-PROJECT AVERAGE FLOWS IN THE LOWER
BRADLEY RIVER DURING THE SALMON SPAWNING PERIOD
(JUNE-SEPTEMBER)
'---------------------TABLE 1 _ __,
Scientific Name
Salmonidae
Coregonus laurettae
Oncorhynchus gorbuscha
Oncorhynchus keta
Oncorhynchus kisutch
Oncorhynchus nerka
Oncorhynchus tshawytscha
Salvelinus malma
Osmeridae
Thaleichthys pacificus
Spirinchus thaleichthys
Gasterosteidae
Gasterosteus aculeatus
Pungitus pungitus
Cottidae
Cottus cognatus
Leptocottus armatus
Clinocottus acuticeps
Pleuronectidae
Platichthys stellatus
Common Name
Bering Cisco
Pink Salmon
Chum Salmon
Coho Salmon
Sockeye Salmon
Chinook Salmon
Dolly Varden
Eulachon
Longfin Smelt
Threespine Stickleback
Ninespine Stickleback
Slimy Sculpin
Pacific Staghorn Sculpin
Sharpnose Sculpin
Starry Flounder
SCIENTIFIC AND COMMON NAMES OF FISH SPECIES
RECORDED FROM THE BRADLEY RIVER DRAINAGE
'--------------------TABLE 2---
Southern District Escapement Goal
Humpy Creek 25,000-50,000
Tutka Lagoon 6,000-10,000
Seldovia Creek 25,000-35,000
Port Graham River 20,000-40,000
China Poot Bay 5,000
Barbara Creek 18,000-24,000
Total 99,000-164,000
Average 1 Escapement
50,000
12,000
40,000
15,000
9,000
5,000
131,000
1983 2
Escapement
104,800
12,900
27,900
4,600
14,100
14,800
179,100
1 Average escapement figures are based on weir counts, ground and
2
aerial surveys conducted between 1951 and 1982. For many streams
only several years data exist (ADF&G 1983b)
Preliminary Data. (Source ADF&G, Anchorage)
LOWER COOK INLET ESCAPEMENT GOALS, AVERAGE
OBSERVED, AND 1983 ESCAPEMENTS OF PINK SALMON
L--------------------TABLE 3---
Turbine Flow (cfs)
Month Minimum Maximum Average
October 438.6 1250.0 522.7
November 438.6 577.0 447.6
December 439.6 456.7 444.0
January 441.8 459.9 446.4
February 444.3 463.7 449.1
March 446.6 468.7 452.1
April 448.1 474.8 455.5
May 447.3 479.3 458.0
June 44.4. 3 473.7 456.7
July 444.4 1074.9 517.7
August 444.1 1250.0 621.2
September 440.2 1250.0 696.4
POWERHOUSE TAILRACE FLOWS FOR THE BRADLEY LAKE
HYDROELECTRIC FACILITY
Note:
Minimum turbine flows represent plant operation with one
unit generation at approximately 38 MW. Actual turbine
flows will be zero when the plant is not generating or
would be less than the minimum turbine flows when the
power demand is less than 38 MW.
~------------------------------------TABLE 4----~
Tide Summer (10 Eft) Winter (25 EEt)
Tide (ft. Exceed-a v (ft5 / S a S a s
proj. datum) ance (%) f~ chan.) S/S
0
0 (ppt) (ppt) 0 (ppt)
a
b
-4 50 0 0 0 0 0
-2 40 156 .51 2 1 5
0 28 328 .69 4 2.8 10
2 18 516 .78 6 4.7 15
4 8 720 .83 8 6.6 20
6 3 940 .86 10 8.6 25
s values assumed to be the maximum salinity at the head of Kachemak
0 Bay
Exceedance is on an hourly basis for 19 years of record of
heights at Seldovia, AK (1963-81)
ESTIMATED TAILRACE SALINITIES FOR SUMMER
AND WINTER CONDITIONS
tidal
s
(ppt)
0
2.5
6.9
11.7
16.6
21.5
L--------------------TABLE 5 -~
Mortality (percentage)
Hours of Exposure (twice daily)
Salinity
(ppt)
28
10-15
3.74
10.5
*
* high incidence of deformity
9.33 6.67
100 50
<4 hrs
0
0
EFFECT OF SALINITY ON MORTALITY OF PINK SALMON EMBRYOS
~------------------------------------TABLE 6
Percent Survival by Tidal Exposure
Percent Tidal Exposure 1
Year 80% 35% 10%
Percent Survival 2 Weeks After Spawning
1960 48 83 90
1961 23 39 40
Percent Survival In Subsequent March
1961 0 20 54
1 Percentages represent percentage of time the intertidal area is
inundated.
Helle et al. (1964)
PERCENT SURVIVAL BY TIDAL EXPOSURE
~-----------------------------------TABLE 7
Reservoir Tailrace Bradley River (RM 5.1)
Month Intake °C oc oc
October 3.4 4.0 4
November 2. 1 2.7 1
December 0 2.7 0
December 1.5 2. 1 0
January 1.5 2. 1 0
February 1.8 2.4 0
March 2.5 3.1 0
April 3.4 4.0 1
May 4.5 5. 1 2
June 5.6 6.2 3
July 6.6 7.2 6
August 6.9 7.5 7
September 5.7 6.5 7
ESTIMATED ANNUAL THERMAL REGIME OF THE LOWER BRADLEY
RIVER AND THE PROPOSED TAILRACE
TABLE 8--
APPENDIX A
FIGURES
'i'P § t? '? '? ~
PROJECT LOCATION
FIGURE 1
PHYSICAL FEATURES OF PROJECT AREA
FIGURE 2 -----'
PROJECT FACILITIES
~----------------------------------------------------------FIGURE 3-----
Life Stage
Spawning
Incubation
Fry
Emergence
Rearing
Outmlgratlon
Jan Feb Mar Apr
PI --Cl --II
lei
dv
--PI
Cl --r-
PI = pink 1al mon
c1 = chum 1almon
11 = coho 1almon
-----
-·
--
PI
Cl
May Jun
--
r---
--.,__
--
-..
!"' -
kl
!'" dv -
Cl --
·!'""
II r--
kl
dv
Ju I Aug Sep Oot Nov Dec
PI
Cl --
1----II
kl -dv -
----------- -
~
1--II
kl
dv
:---
~ -
kl = chinook 1almon
dv = Dolly Varden
- = Abundant
-
PI
Cl
II
kl
dv
--= Pre1ent but not Abundant
PHENOLOGY CHART FOR SALMONIDS KNOWN TO INHABIT BRADLEY RIVER
. FIGURE 4---
20
115
-1-
:: 10 -
6
0
048 1 2 24
...
AVERAGE NUMBER OF HOURS PER OAY WITH TAILRACE SALINITIES
GREATER THAN OR EQUAL TO VALUE INDICATED
4.8 7.2 8.8 12 14.4 18.8 19.2 218 22 8 . 23 6
'\.
' ~
'\ 2SPPT
I ...
1'\.
\ ...
-\ ......... ~ 10 PPT ' ' ~
~ ~ \.
[';~
2 10 20 30 40 60 80 70 80 90 96 88 99
PERCENT OF TIME THAT TAILRACE SALINITY 18 EQUALLED OR EXCEEDED
-SUMMER CONDITIONS
ASIUIIIPTION: NO FRESHWATER
CONTRIBUTIONS AT HIGE TIDE.
SALINITY DURATION CURVES FOR 10 AND 25 PPT BAY SALINITY
...._---------------------.-----------FIGURE 5---
SETON OAM
CAYOOSII OAM
0 2 km
SCALE
LAYOUT OF SETON CREEK HYDROELECTRIC PROJECT
.._-----------------------------FIGURE 6 ---
•
•
-MHHW
4 IIHW
~ 2
~ .. c > "' ....
"' 0 ~ .. c
Q .. u a ·2
II: ..
..
\
' \
I
I
I
I
I
I
I
I -~-, ' ~~ ' ~------------..,.~ --~-~-------------,~---~~~-
,--
1
I
I
I
I APPROX. LEVEL
I OF TIDE FLATS
~RIFFLE REACH
r CROSS SECTION
I 2+11 (LOWER
/ LIMIT OF SPAWNING)
I
..J--APPAOX. WATER
I LEVEL AT LOW
v , TIDE FOR 50cfa
TYPICAL
TAILRACE
CROSS SECTIOH
APPROX. WATER
LEVEL AT LOW
TIDE FOR 450cfa
.. ~--------~--------~-------~------~-------~---~----r----------,
0 20 • 100 120
COMPARISON OF TAILRACE CROSS SECTION
WITH RIFFLE REACH CROSS SECTION
L-------------------FIGURE 7--~
PARTIAL
~
AVOIDANCE '
PARTIAL
RECTIFICATION .,_ __ ---1
PARTIAL
COMPENSATION
IMPACT llENTIFICA nON
I
MmGAnON REQUIRED
~
AVOIDANCE
I
NO AVOIDANCE
+
MINIMIZATION
NO MINIMIZATION
.J,
RECTIFICATION
NO RECTIFICATION +
REDUCTION
NO REDUCTION
~
COMPENSATION
NO COMPENSATION
~
UNMITIGATED/LOSS
RESIDUAL IMPACT
MITIGATION OPTION ANALYSIS
) NO MmGAnON
REQUIRED
TOTAL
~AVOIDANCE
SOME
MINIMIZA Tl ON
SOME
REDUCTION
TOTAL
COMPENSATION
'------------------. FIGURE 8 __ ___.