HomeMy WebLinkAbout150910-False-Pass-Hydro-Recon ReportaLiving Systems DesignFalse Pass Hydro Recon: 20150910
False Pass Hydroelectric Potential
2015 Reconnaissance Report
Prepared for the City of False Pass & APICDA
by: Bob Christensen
20150910
Cover 2. Newly installed stream gage at Unga Man Creek bridge
Cover 1. Unga Man Creek seen from north valley Wall
iLiving Systems DesignFalse Pass Hydro Recon: 20150910
List of Figures .......................................................................................................ii
Background ..........................................................................................................1
Introduction ......................................................................................................................................................1
False Pass, Alaska .............................................................................................................................................1
Current Electrical Generation ......................................................................................................................1
Previous Reports .............................................................................................................................................2
Field Reconnaisance Site Selection ...........................................................................................................2
Waterfall Creek ....................................................................................................3
Location & Land Status..................................................................................................................................3
Geology ..............................................................................................................................................................3
Hydrology ..........................................................................................................................................................3
Fish & Wildlife ...................................................................................................................................................3
Waterfall Creek Summary .............................................................................................................................4
Unga Man Creek...................................................................................................4
Location & Land Status..................................................................................................................................4
Geology ..............................................................................................................................................................4
Hydrology ..........................................................................................................................................................4
Fish & Wildlife ...................................................................................................................................................5
Unga Man Creek Summary ..........................................................................................................................6
Preliminary Design ..............................................................................................6
Overview ............................................................................................................................................................6
Access ..................................................................................................................................................................6
Intake Site and Penstock ...............................................................................................................................7
Powerhouse Site ..............................................................................................................................................7
Transmission .....................................................................................................................................................7
Cost Estimate ....................................................................................................................................................8
Economic Analysis ..........................................................................................................................................8
Conclusion ............................................................................................................8
Summary ............................................................................................................................................................8
Recommendations .........................................................................................................................................8
TABLE OF CONTENTS
iiLiving Systems DesignFalse Pass Hydro Recon: 20150910
Cover 1. Unga Man Creek seen from north valley Wall ......................................................................a
Cover 2. Newly installed stream gage at Unga Man Creek bridge .................................................a
Figure 1. The community of False Palse Global Location Map ........................................................1
Figure 2. Google Earth view of the False Pass Village .........................................................................1
Figure 3. General land status near False Pass, AK. ................................................................................2
Figure 4. False Pass area geology. ..............................................................................................................3
Figure 5. Waterfall Creek seen from Drone at 255’ ..............................................................................3
Figure 6. Small cascade and pool in Waterfall Creek ..........................................................................3
Figure 7. View of Unga Man Creek fromr Drone at 204’ ....................................................................4
Figure 8. View of Unga Man Creek relationship to APICDA fish processing plant ....................4
Figure 9. Stream gage installed near bridge over Unga Man Creek ..............................................5
Figure 10. Stream gage installation locations. .......................................................................................5
Figure 11. Minnow trapping just downstream of the bridge ...........................................................5
Figure 12. Panorama of Unga Man Creek ...............................................................................................6
Figure 13. Preliminary design ......................................................................................................................7
Figure 14. Cost estimate table from Polar Consult Memo .................................................................8
Figure 15. Training City of False Pass Staff ...............................................................................................8
LIST OF FIGURES
Page 1Living Systems DesignFalse Pass Hydro Recon: 20150910
BACKGROUND
INTRODUCTION
Living Systems Design was contracted by the City of False Pass and APICDA to install stream gages
and develop a reconnaisance report for hydro-power options near False Pass, Alaska. A field trip
that included City and APICDA staff was conducted August 24-28 to survey two potential hydro-
power sites and install stream gages in the locations that appeared most feasible for Hydro-power
development. This report summarizes information gathered during this field trip along with addi-
tional research conducted for baseline reconnaisance.
FALSE PASS, ALASKA
The community of False Pass is located at the east-
ern edge of the Aleutian island chain (54°49′40″N
163°23′57″W), just across Isanotski Strait from
the Alaskan Peninsula. It is an isolated coastal
village that is only accessible by boat and plane
(primarily through Cold Bay).
The landscape surrounding the community is
mountainous and spectacular in its beauty with
the Bering Sea to the North and the Gulf of Alaska
to the South. The climate is sub-polar maritime
with cool summers and relatively mild winters.
Annual precipitation averages around 30 inches
with 3-5 feet of snow in the winter. Wind and fog
are common. Sea ice has been known to extend
into the area in colder winters.
There are approximately 50 year round residents who live in False Pass. Most residents participate
in the commercial and subsistence fishing economies to some degree. These folks are joined in
the summer months by approximately 60 part-time residents who are employed at the APICDA
fish processing plant. Other employment opportunities include local government, the school and a
variety of services.
CURRENT ELECTRICAL GENERATION
Electricy is currently provided by diesel genera-
tors (65kW, 90 kW and 150 kW units available
depending on load). The village load averages
around 65kW. Bering Sea fish processing plant
produces their own power through diesel gen-
eration as well and their loads average 75kW.
Energy costs in the village are relatively high,
averaging 71 cents per kWh over the past 5
years. This extremely high rate is typical of ru-
ral Alaskan communities whose primary source
of electricity is diesel generation. The City has
opted to ease the impact of high electric rates on
its residents by providing an annual subsidy of
approximately $150,000 dollars to reduce the cost of diesel used by the power plant. This subsidy
reduces rates to arround 42 cents per kWh but limits the communities ability to invest these funds
in beneficial capital improvements and social services. Power Cost Equalization (PCE) subsidizes an
additional 13 cents per kWh for a final cost to residents of approximately 28 cents per kWh.
Figure 1. The community of False Palse is located on
Unimak island, the very first in the Aleutian chain.
Figure 2. Google Earth view of the False Pass Village.
Airport Village
Harbor
Fish
Plant
Roundtop Mt.
Unga Man
Valley
Ferry
Dock
Page 2Living Systems DesignFalse Pass Hydro Recon: 20150910
PREVIOUS REPORTS
The community of False Pass has been actively seeking alternative energy solutions to provide
greater energy security to the community and reduce the costs of energy to its residents and
businesses. Hydo-power has been noted in most of the reports as potentially feasible. Both wind
and tidal have also been looked at and have provided mixed results in terms of feasibility thus far.
Four reports were reviewed as part of this reconaissance effort:
• A report was written in 1982 that described hydroelectric generation opportunities near False
Pass as not economically feasible. This is not surprising given that the cost of diesel at that
time was a little over one dollar per gallon. (Reconnaissance Study of Energy Requirements
and Alternatives, 1982)
• A more in depth report from 2010 (Herinafter “The Baker report”) looked at a number of
communities in the area and summarized options for wind, tidal and hydro in False Pass.
Recommendations from this report were to prioritize wind and hydro first because these
technologies are more mature and straight forward in terms of operation and maintenance.
For hydro, two creeks were looked at: Unga Man Creek and Waterfall Creek. Both sites
were noted by the authors as worth further investigation with an emphasis on establishing
an annual record of flow to determine economic feasibility. (Renewable Energy Resource
Assessment for the Communities of Cold Bay, False Pass, and Nelson Lagoon, 2014)
• A memo to AEA dated February 17, 2015 was reviewed that looked at two design options in the
Unga Man Creek watershed. The author used gaging data from Russel Creek in nearby Cold
Bay to estimate energy availability for two Unga Man Creek options at capable of providing
140-150kW. It was recommended to develop a flow record and assess aquatic habitat for this
system as the next logical step in reconnaisance. (False Pass Hydro Review, February 2015).
• An initial study of wind energy was reported on in July of 2015. This report confirmed
observations in previous reconaissance work on wind power for False Pass and concluded
that the wind resource is difficult to exploit
because of local turbulence.(False Pass Wind
Energy Feasibility Report, 2015).
FIELD RECONNAISANCE SITE SELECTION
The reports noted above identified a number of lo-
cations for Hydro-power potential near False Pass.
Two of the sites mentioned are located within the
Aleutians Peninsula National Wildlife Refuge. Based
on desk mapping exerises, these sites did not ap-
pear to offer unique power potential and were con-
sidered lower priority options because of the dif-
ficulty expected in obtaining permits necessary for
construction and operation.
Two of the sites noted in previous reports exist on
False Pass Village Corporation land (Isanotski Cor-
poration): Waterfall Creek and Unga Man Creek.
The Isanotski Corporation has expressed interest
in developing power production resources in the
past. Neither of these streams are currently listed
as anadromous in the ADFG Anadromous Waters
Catalog (AWC).
Given these baseline conditions we chose to focus
our reconnaissance field surveys on Waterfall and
Unga Man Creeks.Figure 3. General land status near False Pass, AK.
Page 3Living Systems DesignFalse Pass Hydro Recon: 20150910
WATERFALL CREEK
LOCATION & LAND STATUS
Waterfall Creek cascades to saltwater just .66
miles south of the False Pass airport. The land is
owned by the Isanotski Corporation. The lower
sections of the creek are easily accessible via a
short walk down the beach (at low tide) from the
end of the False Pass airport.
GEOLOGY
Like most of the area surrounding False Pass,
Waterfall Creek basin is mapped as Qtv, Volca-
nics (see figure 4). Unlike most nearby basins,
the Waterfall Creek basin appears to be primarily
bedrock in composition. Small patches of gravel
were noted in a few pool tails in the mainly bed-
rock control channel type.
HYDROLOGY
Waterfall Creek has a basin area of approximate-
ly .26 square miles that draws from a peak el-
evation of 1,000 feet. A field investigation of Wa-
terfall Creek conducted in support of the Baker
report used the bucket method to record a dis-
charge in January 2010 of .67 cfs. Our field crew
also used the bucket method and recorded a flow
of approximately .29 cfs on 20150924. Based on
the the complete lack of snow pack available to
provide runoff during our field investigation it ap-
pears likely that Waterfall Creek is at least par-
tially spring-fed.
FISH & WILDLIFE
Waterfall Creek is not mapped as an anadromous
stream in the AWC. Our site survey confirmed a
barrier to fish passage (the falls) is a certainty at
the intertidal zone. It is possible that the stream
contains resident fish but we did not trap the
stream to make a determiniation. Our foot sur-
veys found spawning substrate and pool habitat
for potential resident fish to be extremely limited.
The area surrounding Waterfall Creek is covered
by Salmonberry thickets and alder shrubland
patches. A variety of birds and mammals like-
ly use the area as foraging and cover habitat.
Although impacts from construction and plant
operation would be associated with developing
Hydro-power at this site it is not believed that
they would be significant enough to require miti-
gatory action with proper environmental design.
Figure 4. False Pass area geology.
Figure 5. Waterfall Creek seen from drone at 255’ el-
evation above sea level.
Figure 6. Small cascade and pool in Waterfall Creek.
Page 4Living Systems DesignFalse Pass Hydro Recon: 20150910
WATERFALL CREEK SUMMARY
According to calculations provided in the Baker report, power potential for Waterfall Creek is likely
limited to approximately 2-10 kWh. Our investigations confirm this range. Given the limited power
potential and potential difficulty in developing access to an intake site through rugged bedrock
topography, we concluded that Watefall Creek would not be capable of having a signficant posi-
tive impact on energy security or costs for the community of False Pass. The site may be suitable
for a small, off-grid development of some kind (e.g. fishing lodge) as long as the system could be
designed without the necessity of road access to the intake structure.
UNGA MAN CREEK
LOCATION & LAND STATUS
Unga Man Creek flows to saltwater 1.2 miles
north of the community False Pass (54°52’23” N
163°24’54” W), just before the terminus of the
northern portion of the community road system.
The majority of the watershed is owned by the
Isanotski Corporation, with the uppermost por-
tions managed by the Aleutians Peninsula Na-
tional Wildlife Refuge. The lower reaches of the
creek are easily accessible via the road system,
including a bridge with provides access to the
community dump just north of the creek.
GEOLOGY
Like most of the area surrounding False Pass,
Unga Man Creek basin is mapped as Qtv, Volca-
nics. The watershed includes a number of highly
active alluvial fans, including the mainstem of
Unga Man Creek and the two primary tributar-
ies. Substrate between the lower extent of our
survey (beginnning at the bridge) and including
approximately 1 mile upstream included sand,
gravel, cobble and boulder with the surveyed
reaches dominated by gravel and cobble and the
upper reaches dominated by cobble and gravel.
No exposed bedrock was identifiied in or near the
channel for the entire survey length.
HYDROLOGY
Unga Man Creek has a basin area of approxi-
mately 3.9 square miles that draws from a peak
elevation of 2,700 feet. A field investigation of
Unga Man Creek conducted in support of the
Baker report used the Drogue method to record
a discharge in January 2010 of approximately 10
cfs. Our field crew used a Global Water Systems
“Flow Probe” to record four manual discharge measurements in Unga Man Creek over the course of
our field survey that ranged from 6.3 cfs to 8.7 cfs. Conversations with a number of local residents,
the historically low snow accumulations from the previous winter and the the lack of precipitation
preceding the timing of our field trip suggest that the the flows we recorded should indicate an ap-
proximate low flow for the watershed during the Summer months.
Figure 7. View of Unga Man Creek watershed taken
by drone at 204 feet above sea level.
Figure 8. View of Unga Man Creek relationship to
APICDA fish processing plant and North end of town.
Page 5Living Systems DesignFalse Pass Hydro Recon: 20150910
A memo assembled by Polar Consult in support of
this reconnaissance report calculated an estimat-
ed annual range of flow from 3 - 25 cfs for Unga
Man Creek based on the USGS record provided
at Russel Creek in nearby Cold Bay (see attach-
ment). It was emphasized in this report that the
flows at Russel Creek provide only a very rough
estimate of flows in the Unga Man watershed but
that these were the best data available for recon-
naissance.
The City and APICDA recognize the importance
of establishing an emperical record of flow for
Unga Man Creek as a critical step in determining
Hydro-power feasibility and upon their initiative
we installed two stream gages to begin that pro-
cess. The first site was located just downstream
of the bridge that crosses Unga Man Creek and
the second site was located approximately .2
miles upstream of the bridge site (see figure 10).
Site selection was fairly challenging because of
the lack of bedrock anywhere within the sur-
veyed channel length and the limited availability
of stable pool features. The size of the substrate
within the channel and the bankfull width of the
creek both indicate that annual flows are high at
times. Large Boulders were used for anchoring
both gages (See figure 9). Stainless Hobo Water
Loggers were installed in stilling wells along with
staff gages. Each station also includes its own
barometric correction logger. City of False Pass
staff were trained in using the Global Water Sys-
tems flow probe for manual discharge measure-
ments and they will be doing the field work nec-
essary to establish a rating curve for interpreting
the water logger data.
FISH & WILDLIFE
Unga Man Creek is not mapped as an anadromous
stream in the AWC, however, our site survey en-
countered approximately 1,500 pink salmon over
the course of the surveyed stream length. The
Pinks were noted as attempting to spawn but no
reds were identified. The size of the substrate in
the sureyed length may be prohibitive to much
success for Pink salmon spawning. It is worth
noting that 2015 was a very big Pink salmon year
with the third largest catch ever recorded.
Five minnow traps were set in pools encounted
along the survey length and were baited with
salmon eggs. The traps soaked for five hours and
no juvenile or resident fish were caught.
Figure 9. Stream gage installed near bridge over Unga
Man Creek. Aluminum angle was cut and bolted to a
large boulder and provided a mounting structure for
a stilling well and staff gage.
Figure 10. Stream gage installation locations.
Figure 11. Minnow trapping just downstream of the
bridge. Note spawned out Pink salmon in the back-
ground.
Page 6Living Systems DesignFalse Pass Hydro Recon: 20150910
The area surrounding Unga Creek is covered by Salmonberry thickets and alder shrubland patch-
es. A variety of birds and mammals likely use the area as foraging and cover habitat. Although
impacts from construction and plant operation would be associated with developing Hydro-power
at this site it is not believed that they would be significant enough to require mitigatory action with
proper environmental design.
UNGA MAN CREEK SUMMARY
According to calculations provided in the Baker report, power potential for Unga Man Creek may
average 69 kWh. Our investigations would suggest that the hydrology of this basin could exceed
this estimate. Much will depend on additional field work to determine the nature of Unga Man
Creek’s aquatic ecology, developing a local record of flow and determining the details of an even-
tual project design. That having been said, the results of previous studies and the field reconnais-
sance summarized here suggest that Unga Man Creek could meet the communities energy demand
for most of the year and provide one of the best options identified for community energy to date.
PRELIMINARY DESIGN
OVERVIEW
A run of the river design for Hydro-power appears to be worth further investigation at Unga Man
Creek. A relatively easy to access intake site was identified at 250 feet above sea level, just down-
stream of the confluence of the two major tributaries, that would provide a collection point for the
majority of the flow within the watershed. A powerhouse site could be easily located downslope of
the community dump at approximately 50 feet above sea level. This design would provide a gross
head of 200 feet (see figure 13).
ACCESS
Access to Unga Man Creek appears to be very straight forward. An existing road extends and
crosses the creek and has already been roughed in to the powerhouse site noted above. Access
to the intake site noted in this preliminary design could be constructed over what appears to be
relatively easy road building conditions with limted to no bedrock cutting necessary and a mild and
mostly consistent gradient over alluvial and colluvial deposits. One small wetalnd area would need
to be crossed and designed for as well as numerous steeper gradient ephemeral streams.
Figure 12. Panorama of Unga Man Creek taken from the North side of the valley looking South across the pre-
liminary desgin project area described below.
Page 7Living Systems DesignFalse Pass Hydro Recon: 20150910
INTAKE SITE AND PENSTOCK
The intake site identified for this preliminary design was selected at a natural channel narrowing
just downstram of the confluence of the two major tributaries to Unga Man Creek. This site would
provide an access point that would support a penstock route that would rapidly exit the active
floodplain and could be buried in the access road for the rest of its decent to the powerhouse. This
site would necessitate a design that could be anchored in alluvial sediments of cobble and boulder
and may require some channel stabilzation upstream to keep high flow events from moving the
channel around the intake site. This site would also need to be designed to withstand high flow
events and transport relatively large quanties and sizes of bedload. Of all of the infrastructure in-
cluded in this preliminary design, the intake structure looks to be the most challenging.
POWERHOUSE SITE
A powerhouse site could be located downslope of the community dump in a location that would
support easy construction of a tailrace return of the water approximately 20 feet in elevation above
where the creek meets saltwater.
TRANSMISSION
A transmission line from the powerhouse could be run back over the bridge and along the existing
road for approximately 3,000 feet to connect to the community grid.
Figure 13. Preliminary design for Unga Man Creek run of the river Hydro-power project.
Intake
Power-houseRoad & PenstockTransmission
Unga Man Watershed
Page 8Living Systems DesignFalse Pass Hydro Recon: 20150910
COST ESTIMATE
Polar Consult prepared a project performance and design cost estimate memo in support of this
reconnaissance report that included an estimated costs for feasibility, design, permitting, and
construction shown below.
ECONOMIC ANALYSIS
Using the estimated costs included in the table above, the AEA Economic Model worksheet was
used to develop an input to benefit ratio of 1.82.
CONCLUSION
SUMMARY
Based on the information provided in this rec-
onaissance effort, a run of the river Hydro-power
project looks to be a viable option for greatly en-
hancing community energy security and afford-
abilty. Working with Polar Consult, a preliminary
project design (see attachment) is estimated
to support a design capacity of 125 kW, which
would meet approximately 86% of the False Pass
Utility load.
RECOMMENDATIONS
In addition to establishing a record of flow using
the existing stations, we recommend the instal-
lation of an additional station closer to the pro-
spective intake site included in the preliminary
design. Given the alluvial nature of the Unga Man
Creek basin, including what appears to be a very
substantial hyporheic zone, it may be possible
to access more water than is indicated by the
stream gaging stations near the bridge.
It is also clear that addtional geotechnical surveys could provide important design criteria for the
intake site.
We also reccomend that additional minnow trapping and spring beach seining be performed to
better characterize the aquatic ecology of this stream, particularly whether the stream warrants
an AWC designation. When paired with mapping of potential spawning habitat should inform the
question of whether a water reservation would be necessary for maintaining fish habitat.
Figure 15. Training City of False Pass staff to conduct
manual flow measurements for establishing the rat-
ing curve for stream gages in Unga Man Creek.
Figure 14. Cost estimate table from Polar Consult Memo (see attached).