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Cosmos Hills Technical Review
and Assessment of Alternatives
October 2011
Prepared by WHPacific, Inc.
Cosmos Hills Technical Review and
Assessment of Alternatives
Prepared by WHPacific, Inc.
1. OVERVIEW
This technical memorandum presents the results of WHPacific, Inc.'s review and assessment of
alternatives in support of the proposed small-scale hydroelectric feasibility study in the Cosmos Hills
area. This technical review was conducted between July and September of 2011 and involved
representatives from Alaska Village Electric Cooperative (AVEC) and NANA Regional Corporation, with
technical assistance from WHPacific, Inc., NANA Worley Parsons, GW Scientific LLC, Golder Associates,
and DOWL HKM.
The Cosmos Hills hydroelectric project includes four creek drainage study alternatives: Kogoluktuk River,
Wesley Creek, Cosmos Creek, and Dahl Creek. The assessment included a review and assessment of
work done to date, including hydrology, hydroelectric modeling, environmental, conceptual engineering
considerations, and site prioritization. There were a variety of references and key informants consulted
in this technical memorandum. This technical memorandum includes the following:
• Hydroelectric and hydrology assessment
• Site prioritization
• Design considerations
• Preliminary geotechnical investigation and summary: Kogoluktuk River and Wesley Creek
hydropower sites
• Wetlands and fisheries summary Kogoluktuk River
• Sub-regional energy delivery overview
• Discussion and recommendations
2. HYDROELECTRIC & HYDROLOGY ASSESSMENT
Updated stream flow and topographic information gained through the Cosmos Hills Hydrology Network
was used to reassess the four project sites recommended for further study in WHPacific's 2010
reconnaissance report. These sites include Cosmos Creek, Wesley Creek, Dahl Creek, and the Kogoluktuk
River, as shown in the map below.
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Cosmos Hills Technical Review and Assessment of Alternatives
Hydroelectric Power
..L!"aeka VIllage Electric Cooperative
·r o aun.ey AIM • -·
• Powerllouse Penstodl
.Mot:zt.:I010 WHP -fi ~...;.u.:,~-:.,'= act c
Figure 1: Location of possible hydroelectric sites in the Shungnak-Kobuk area
The Cosmos Hills Hydrology Network was established in August 2010 with the objective of providing
climatic and stream flow conditions in the study area and the specific creeks of interest. Water level
gauges and temperature stations were established at the approximate locations of future intakes and
powerhouses, respectively . Figure 2 provides an example of the 15 minute water level record collected
to mid -August 2011 for Cosmos and Wesley Creeks.
2
Upper Cosmos Creek Gauging Station
102 l -Or a nWaler Elevation t e Calibration Dab
E • OAOC Data
~ 101
c
~ .8 100
<
1G .,
LL 99
..!:
ii _g> 98
Ice Affected -
Avalanche
Snow Dri ft
Flooding
Cosmos Hills Technical Review and Assessment of Alternatives
Upper Wesley Creek Gauging Statlon
93.0 r.=======:;,---.---r---,-r--r--.-, .l PT2 W ater !Jevafton !
92.8 e CaiiJmtlon Data
• OAOCDa la
~ 92.6 ------
8 92.4
~ 92.2
~ 92.0 .,
LL 91 .8
..!:
ii 91.6
_g>
~ 91.4
§ 91 2
'" C) 111 .0
..
I \...U-J.f.
:r ., J\~ "' 'TT :::1 ..
C) rv_~M...~ .... _J.J
96
l>ug Sep Oc:t No• Dec Jan Fell Mar ~ May Jun Jul AUQ 1>ug Sop Oct Nov Dec Jan Fob Mar ~ Mlly J"' Jul Aug
2010 2011 2010 2011
Figure 2: Water level records for Cosmos and Wesley creeks (August 2010-2011) (GW Scientific)
Ice influenced the water level gauging sites on the Cosmos, Dahl, and Kogoluktuk from mid-October to
mid-May and to a lesser extent on Wesley. Water temperature records suggest Wesley Creek may have
a larger groundwater component that delays or prohibits the formation of solid ice cover. Th is attribute
may prolong the potential generation season and reduce the potential for icing of an intake structure.
From the water level measurements (creek or river stage), a preliminary stage-dis charge relationship
was developed for each site to translate water level information to stream flow (discharge). Each of
Cosmos, Wesley, and Dahl creeks have had 10-11 stream f low measurements completed and referen ced
to a fixed survey datum. Due to the river size and ice issues experienced at the Kogoluktuk site, only four
Acoustic Doppler Current Profile (ADCP) measurements were ava i lable for the development of a stage-
discharge curve. Due to the low confidence in a stage -dis charge curve with so few points, the U.S.
Geological Survey (USGS) gauge on the Kobuk River near Kiana (15744500) was used as a proxy and unit
runoff values derived from drainage area were used to estimate monthly average flow values. Figu r e 3
shows the stage-discharge curve developed for Wesley Creek.
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Cosmos Hills Technical Review and Assessment of Alternatives
Wesley Creek Stage-Discharge Curve
92.00
91.90 -Calculated Data
• Measured Data
~ '91.80
E
:::1
.! 91.70 ---
Q= 4.2933{Stage-90.12jS-6407
• ~
~ 9Lro -------~~-------------------------------------..
.I:.
.!JI
~ 91.50 ----------------------------------------------------------:.
:::1
..; 91.40 ------/----------------------------------------------------,
= :;; 91.30 -/--------------------------------------------------------1
0 25 so 75
Flow(ds)
100 125
Figure 3: Wesley Creek Stage-discharge curve developed from August 2010-2011 data
150
Using the stage-discharge curve, the 15 minute water level data was converted to flow. These flow
values were used to determine the potential generation available from each site, along with the
elevation difference between the intake and powerhouse. As was previously noted, the gauging sites
were located in the approximate locations of the intakes and powerhouses. The elevation difference
between these gauging sites was calculated by subtracting the powerhouse gauge elevation from the
intake gauge elevation . To calculate the potential powerfrom a site the following equation is used:
P='l}gQH
Where :
P =Power in kW
1J =efficiency (65-90%, Note: smaller units tend to have lower efficiency ratings)
g =gravity (9.81 m/s2
)
Q =flow (m 3/s)
H = height(m
Using the updated flow and elevation data, the four sites were reassessed. Table 1 provides a summary
of the reassessment .
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Cosmos Hills Technical Review and Assessment of Alternatives
Table 1: Summary of potential hydroelectric sites in the Upper Kobuk region.
Hydroelectric Drainage Installed
site area, sq. capacity,
mi. kW
River
Summary Table Colour Legend
Est. net Est. hydraulic
head, ft. capacity, cfs
#of
units
Turbine type
Archimedes Sc
Based on the above information, Dahl Creek is not recommended for further consideration by AVEC due
to the lower-than-expected elevation difference between the intake and powerhouse locations. This has
the effect of reducing the potential generation from the Dahl Creek site to a value below the peak village
demand of Shungnak and Kobuk. Flows were also lower than expected within the Dahl Creek valley,
although it is noted that 2011 has been below 14 years of median flow values based on information
gathered from the USGS Dahl Creek gauging location (15743850}.
Due to the lower-than-expected flows observed in Cosmos Creek, the potential generation has been
reduced, even though the elevation difference was found to be greater than originally estimated. With
the reduction in capacity and consideration of the remoteness of the site, Cosmos Creek is not
recommended for further consideration by AVEC for village electrical generation . If infrastructure
improves (i.e., a transmission line is developed between Shungnak and Ambler}, Cosmos Creek may be
considered in the future should electrical demand support such an initiative.
With the least amount of change from the original estimated values, Wesley Creek is recommended for
further consideration by AVEC. Flows from Wesley Creek may also be available longer into the fall
season due to the warmer water temperatures noted earlier. This attribute should be reviewed in
greater detail and continue to be monitored.
Insufficient flow data exists for the Kogoluktuk River site to remove it from consideration. Additional
flow monitoring and modification of the existing water level data collection system is recommended to
gain a better understanding of flows in the Kogoluktuk River. While the flow dataset used for the
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Cosmos Hills Technical Review and Assessment of Alternatives
evaluation suggest reduced generation capacity, the generation potential remains above the peak
electrical demand of 660 kW for Ambler, Shungnak, and Kobuk.
A hydroelectric development on the Kogoluktuk River also has the greatest potential to provide
electricity for thermal heating by shaping generation to meet demand using a small dam. In the current
runoff regime, flows tend to be high when electrical demand is low {spring and summer). If the
Kogoluktuk site were to be developed with some water storage capacity, the generation season could be
prolonged, permitting electrical demand to be met and allowing any excess power to be used to serve
the thermal load through water or space heating. Because of this, the Kogoluktuk site is recommended
for continued consideration.
Table 2: Potential run-of-river hydropower sites in the Upper Kobuk region
Criteria, each Proximity to Appropriate Estimated Expected Reduction in Total
weighted 20%, and electric installed cost of length of Diesel fuel I score
ranked 1 (worst) to load/existing capacity, to installation hydropower capital cost
5 (best): power line service perkW generation
and road existing elec. season
access demand ·-
Wesley Creek 5 4 3 4 5
Dahl Creek 5 1 2 3 3 •..
Kogoluktuk River 2 2 5 4 1
(run-of-river)
Cosmos Creek 3 3 2 3 2
As shown in Table 2, Wesley Creek appears to be the most attractive economically and e.nvironmentally
to develop, and is recommended for further study. With an estimated capacity of 428 kW, this site is
most appropriately scaled for the summer energy needs (370 kW) of Shungnak, Kobuk, and Ambler, and
is located relatively close to existing road and power line infrastructure. Figure 4 shows the potential
generation from a hydroelectric development on Wesley Creek compared to the electrical demand from
Shungnak and Kobuk {S-K), as well as Ambler, Shungnak, and Kobuk {A-S-K).
6
4.2
2.8
2.8
2.6
Cosmos Hills Technical Review and Assessment of Alternatives
Resource Supply/Demand Comparison
700 -------------------------------------------------------------.
600 +---1 --------------------------------------------------------l
-S-IC Demand
t:tt-----------1-A-s-IC Demand 1---------------------..---------::--ll
-W~sll!!yC..n
0
1·Jan 31-Jan 2-Mar 1-Apr 1-May 31-May 30.Jun 30-Jul 29-Au& 2~5ep 2&0ct 27-Nov 27-oec
Date (dd/mmm)
Figure 4: Resource Supply/Demand Comparison
3. DESIGN CONSIDERATIONS
Site investigations were initiated following the 2010 reconnaissance study that identified four potential
hydroelectric sites for further study. The focus of these investigations were to confirm model values
used for flows and elevation difference in the field to determine if the sites identified were suitable for
further analysis and potential development. Preliminary environmental and geotechnical assessments
were also undertaken to provide further information on each site. When assessing multiple sites,
common data collection and field assessment techniques are required to complete the comparison to
reduce the potential for a site to be prematurely discarded . At this time, all four sites have had an
environmental and geotechnical reconnaissance field assessment.
The information below summarizes the data that has been collected and expands on the design
considerations outlined in WHPacific's 2010 reconnaissance report that recommended further study of
Wesley, Cosmo ,s and Dahl Creeks and the Kogoluktuk River . Based on the outcome ofthe hydroelectric
assessment presented previously, the focus of this section will be on Wesley Creek and the Kogoluktuk
River .
• Intake. The location for the Wesley Creek intake is heavily vegetated with large rock outcroppings.
The stream bed is comprised mainly of gravels, rocks, and large cobbles. In the upper reaches, the
stream is confined by weathered rock side slopes. There is a thin layer of overburden. The depth of
the weathered rock materials was not determined. The degree of degradation caused by the
weathering is unknown at this time and has the potential to increase costs if competent material
cannot be found close to the surface.
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Cosmos Hills Technical Review and Assessment of Alternatives
The geotechnical aspects of a site tend to remain the largest risk component until the site is fully
assessed by a drill program or constructed. Due to the high costs of a drill program that may be
inconclusive, designers and contractors often accept the risk and modify the design as conditions
are confirmed during construction. The geotechnical investigation hit refusal during their site visit,
but the testing was done early enough in the year that it may not have been permafrost but frozen
active layer. Permafrost is discontinuous in several areas along the creek and further mapping in the
area ofthe Wesley Creek intake is recommended.
Another aspect that requires further investigation is the potential for sediment transport. While the
intake can be designed with some self-cleaning features, the size and quantity of suspended
sediments are a key consideration for both intake design and turbine fabrication. Water samples
and stream bed samples should be collected and analyzed for material type/hardness and grain size.
• Penstock. The penstock route will follow the designated access route through low gradient areas
between the powerhouse and intake sites. Actual routing will depend on site conditions, but the
design intent is to minimize the length ofthe penstock to reduce materials costs and head losses. A
preliminary terrain assessment has been undertaken and has identified areas of discontinuous
permafrost along all streams. To address this, the penstock will be designed to be a combination of
buried and elevated sections depending on ground conditions encountered.
• Powerhouse-Civil. The area has limited seismic activity, magnitude 4 to 5. No visual faults were
observed while on the ground or flying over. The design of the structure will be developed using
acceleration values with a 10 percent probability in 50 years or better. The conceptual
tailrace/powerhouse location for Wesley Creek study area is located within the creek channel flood
plain with likely sand and gravel deposits that are expected to be unfrozen. If granular material is
present, a shallow depth reinforced concrete foundation system could be used. The concrete
foundation could be constructed on properly compacted structural fill over properly compacted
subgrade granular material. Any localized areas of deeper fine grained material deposits would
require a deeper excavation to prepare a properly compacted granular foundation base. Alternative
foundation options include driven piles and helical anchors 1
. Based on the outcome ofthe
hydroelectric assessment a detailed geotechnical investigation is recommended for Wesley Creek in
the vicinity of the powerhouse. If depth of the permafrost and/or the bedrock is determined, then
other foundation systems may be feasible and more cost effective.
• Powerhouse-Electrical Mechanical. To determine the best generation option for site conditions
turbine and generator manufacturers should be contacted. Once site characteristics are confirmed
the manufacturer can optimize a water to wire package that would address the turbine, generator,
switchgear and protection. Given the remoteness of the site a modular facility, designed and
constructed in a controlled environment and then transported to the proposed site should be
considered.
• Tail Race. The lower reaches of Wesley Creek open up into a larger floodplain/floodway with alluvial
sands and gravels. No noticeable beaver dams were observed. Fish were present, particularly in the
lower reach, and the discharge works will need to be designed to minimize impacts and where
possible enhance the habitat.
• Transmission line. The transmission routing for Wesley Creek would entail a short ~2 mile
transmission line that would connect to the Shungnak-Kobuk intertie. A small substation would be
required to facilitate the tie in. A transmission line to deliver electricity generated from a facility on
1 See page 16 of Golder Report
8
Cosmos Hills Technical Review and Assessment of Alternatives
the Kogoluktuk River could tie in directly in Kobuk. The routing of such a transmission line would
require further analysis.
• Access Roads. A detailed review and assessment of access roads to the two sites has not yet been
undertaken. However, there is a substantial amount of road and access work occurring in the sub-
region that could assist in accessing these two sites. Tribal entities in Ambler, Kobuk, and Shungnak
each receive between $100,000 and $200,000 annually from the Bureau of Indian Affairs to assist
with transportation, planning, design, construction and maintenance. Their transportation programs
could assist in the development of access planning to proposed hydro sites. Once a route
is identified, the Tribe(s) could elect to pursue additional funding for design and construction of the
route. A separate transportation planning effort is taking place to extend the Kobuk Bornite Road to
the Arctic deposit. This work should also be coordinated with hydro site access and depending on
location may assist in route development. Finally, the State of Alaska's Department of
Transportation has commissioned the Ambler Access study. This has potential to benefit access to
these sites through an improved and coordinated effort.
4. PREliMINARY GEOTECHNICAL INVESTIGATION: KOGOLUKTUK RIVER HYDROPOWER SITE.
A preliminary geotechnical investigation was conducted by WHPacific's senior geologist, Steve Buckley,
during the week of August 29, 2011 for the Kogoluktuk watershed and funded by NANA Regional
Corporation. The final report will be available by December 2011. Therefore, design considerations for
the Kogoluktuk are presented in a fairly succinct manner. A summary ofthis field work is provided
below.
Two reaches of the Kogoluktuk River were evaluated for geotechnical considerations. This included
bedrock geologic and structural mapping along with shallow soil probing and a review of stream and
slope stability. The results show a variety of landforms associated with two main bedrock-controlled
cascade reaches. Bedrock consists of very competent granitic gneiss with a shallow north dip in both
reaches. This bedrock controls upstream and downstream nickpoints and most of the stream reach is
underlain by exposed bedrock. The most important structural fabric is a shallow north-dipping foliation
(20-30 degrees).
Shallow soils are developed both directly on bedrock and on shallow glacial outwash and ice-marginal
deposits. These deposits range from well-sorted cobble and gravel alluvium to fine-grained sandy
outwash to silty loess. Organic-rich Histosols are developed directly on bedrock in some shallow
wetlands. No evidence of permafrost was encountered to the maximum depth of excavation
(approximately 2'). This may reflect the well-drained characteristics of the soils in the area.
There is no evidence of slope instability such as solifluction or slumping, or hydrologic or vegetative
evidence of slope instability on air photos. There are some shallow scarps developed along the
immediate cutbacks of the river especially on outside bends in alluvial reaches.
5. PRELIMINARY SUMMARY GEOTECHNICAL INVESTIGATION: WESLEY CREEK HYDROPOWER SITE
The Wesley Creek geotechnical considerations were previously documented in the 2010 report
completed by Golder Associates titled: "Geotechnical Reconnaissance Report: Alaska Village Electric
Cooperative-Cosmos Hills Hydroelectric Feasibility Study." A summary is provided below.
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Cosmos Hills Technical Review and Assessment of Alternatives
• Lower Reach. The vegetation within the flood plain at the lower reach of the study area and at the
tailrace/ powerhouse vicinity consisted of tall mature spruce with willow and other shrubs. The
vegetation outside of the flood channel at the lower reach is generally similar with decreased
density. The stream channel bottom generally consisted of cobble with smaller diameter granular
deposits at areas of lower velocity stream flow.
The shallow depth test pits within the flood plain at the lower reach generally showed a thin organic
vegetation mat up to several inches in thickness, overlying silty sand deposits with underlying sandy
gravel deposits with cobbles (STP 133, STP 134, and STP 135). The hand probes returned refusals on
gravel and cobble at depths ranging from 8 inches to 2 feet. The vegetation patterns in the aerial
photography suggest that localized areas of flatter topography could include wetlands and increased
depths of fine grained deposits of silt and sand. Frozen soils were not encountered within the
exploration limits of the hand tools, which extended to depths of 2 feet maximum within the
granular material.
The shallow depth subsurface conditions outside of the flood channel consisted of alluvial and
eolian deposits of finer grained silt and sand. Within the sparser vegetation areas, hand probes
showed refusal on frozen ground at depths ranging from 3 to 3.5 feet. However, frozen ground
refusal could have been remnants of seasonal frost. The area included a tall spruce canopy of
increased spacing with sparse shrubs. At lower elevations, below the study area, general signs of
permafrost consisting of polygonal patterned ground were subtly evident from the aerial view of the
plane ride to and from Kobuk. Discontinuous permafrost conditions outside of the flood channel
along the lower reaches of Wesley Creek should be expected in isolated areas.
• Middle and Upper Reaches. The middle and upper reaches of the Wesley Creek study area
transition into steeper valley side slopes, more specifically on the western border. The channel
becomes more constricted by the toe of the valley wall on the western border and the gentler slope
on the eastern border. Upstream of the intake location, localized areas of colluvium and weathered
and highly fractured rock and rock debris existed at areas on the valley slopes. The vegetation within
the flood channel at the middle and upper reaches of the study area consisted of densely spaced tall
willow and alder shrubs with mature spruce that decrease in size and density with increasing
elevation. The vegetation outside of the flood channel at the middle and upper reaches transitions
to sparse shrub and stunted spruce.
Above the conceptual intake location, the valley becomes broader with increased shrub density. The
shallow depth test pits within the flood channel at the middle and upper reaches generally consisted
of a thin organic vegetation mat up to several inches in thickness overlying alluvial silt and sand with
underlying gravel deposits with cobble. The depth to the surface of the coarser grained granular
alluvial deposits of gravel and cobbles ranged from 4 inches to 3.3 feet as observed in the test pits
and hand probes. The vegetation patterns and topography infer that localized areas of flatter
topography could include wetlands and increased depths of fine-grained deposits of silt and sand
overburden. The general subsurface conditions outside ofthe channel included thin vegetation
cover with organic silt overlying weathered colluvium and alluvial deposits of coarse material.
At a higher elevation on the valley slopes, colluvium, talus, and fractured and weathered bedrock
outcrops exist with thin vegetation cover and shrubs at localized areas. Generally, the hand tools
limited subsurface observations to the top 12 inches. The limited observations were not deep
enough to determine if permafrost soils were present. Generally, due to the granular nature of the
soils and larger void spaces associated with larger-diameter deposits, permafrost soils would include
a deeper active layer depth, if permafrost is present. Large-scale indications of slope instabilities
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Cosmos Hills Technical Review and Assessment of Alternatives
were not observed on the valley side slopes. Small localized areas of talus and colluvium exist at
steeper slope areas.
6. WETLANDS & FISHERIES SUMMARY-KOGOLUKTUK RIVER
A reconnaissance-level wetlands and fisheries investigation was conducted by WHPacific the week of
August 29, 2011 for the Kogoluktuk River. The study was funded by NANA Regional Corporation. Final
reports will be available during the winter of 2012. For wetlands and fisheries information on Wesley
Creek, refer to "Reconnaissance Fisheries Report: Cosmos Hills Hydroelectric Feasibility Study" and
"Reconnaissance Report: Wetlands and Other Waters of the United States Cosmos Hills, Kobuk River
Valley, Alaska." A summary of the field studies is found below.
The Kogoluktuk River study area was modified upon viewing the site from the helicopter on the first day
of fieldwork to include an additional cataract downstream, extending the study area by about 1.2 air
miles downstream. The study area was shortened at the upstream end by about 0.9 air mile, while still
including a stream reach for fisheries studies above the upper cataract. The purpose of the change was
to characterize fish presence and habitat below the lower cataract, which appeared to present a similar
opportunity for a hydropower site to the upper cataract. Extending downstream also allowed us to
assess potential anadromous fish habitat and barriers to fish passage (see below).
• Fisheries Studies: Kogoluktuk River: The Kogoluktuk River was sampled in three sections. The three
sampled reaches included a reach below the cataract/falls area at the downstream end of the study
area, a reach between the downstream cataract/falls and the upstream cataract, and a reach
upstream of the cataract near the upstream terminus of the study area. The downstream-most
cataract is a possible upstream migration barrier to fish passage. The upstream cataract is likely
passable, if the downstream cataract were passable. At each stream reach, the field team sampled
representative habitat that was accessible by wading. The downstream-most reach afforded the
most diverse habitat of the three reaches and included side channels, plunge pools, sheltered
margins, braided channels, limited woody debris, and large substrate. This stream reach also yielded
the largest diversity of species (6), including chum salmon. Chum salmon carcasses were common in
the reach and numerous active redds were observed just upstream of the sampling area.
The central stream reach was markedly less diverse in habitat availability and in species collected.
Only two species, slimy sculpin and grayling (juveniles), were collected in the reach. Salmon, alive or
dead, and redds were not noted in the reach. Habitat in the central reach is dominated by bedrock,
larger boulders, and deep runs. All fish were generally collected along the margins ofthe river. A
tributary enters on river right near the center of the middle reach and the upstream end of the
sampled area is bound by the bottom of the cataract.
The upstream reach is characterized by continuous riffles of moderate depth. Little habitat diversity
is present in the upstream reach. Two fish species, slimy sculpin, and Arctic grayling were collected
in the upstream reach, primarily along the river margins. There was no sign of salmon or salmon
spawning activity.
• Fisheries Study: Wesley Creek. As a follow up to last year's sampling effort, WHPacific completed a
spawning survey in Wesley Creek downstream of the most downstream reach sampled during the
previous year. The team observed approximately 1,000 feet of stream channel to document
potential salmon presence, carcasses, redds, and suitable spawning habitat. Despite the availability
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Cosmos Hills Technical Review and Assessment of Alternatives
suitable spawning substrate and habitat, but we did not observe salmon presence or use. In
addition, we did not observe grayling in the reach despite the presence of likely habitat.
• Wetland Studies. WHPacific performed a reconnaissance level survey of wetlands within the study
area using an on-foot survey that investigated over 30 representative areas of potential wetlands
and "waters" previously identified on the aerial photograph. We identified three broad classes of
wetlands: 1. floodplain areas adjacent to ordinary high water line on the Kogoluktuk River, 2.
localized depressions on the terrace above the river, and 3. broad hill slopes. We recorded the
position of each of these features using a hand-held GPS unit, made notes on vegetation and
hydrology, and took photographic records. Floodplain wetlands are typically narrow gravel bars or
low benches dominated by willow and other shrubs. Localized depressions capture down-slope
drainage and vary from open water ponds, palustrine emergent marshes, and open or closed-
canopy palustrine shrub-scrub or forested areas. Hill-slope wetlands are extensive in some places,
and are typically palustrine-emergent marsh or palustrine shrub-scrub, with sparse tree cover.
Typical plant species in the depressional and hill-slope wetlands include black or white spruce,
Labrador tea, dwarf birch, bog blueberry, willows, sedges, and cottongrass. Soils typically consist of
a surface layer of organic material over gravelly or sandy glacial materials. We also identified a
number of streams in addition to the Kogoluktuk River, including California Creek, Lynx Creek,
Glacier Creek, Radio Creek, and several smaller unnamed streams that drain from wetlands on the
terrace.
After "field-truthing" areas initially identified on the aerial photo as potential wetland, we found
that all wetlands could be readily identified by color and textural aerial photo "signatures." Wetland
features are fairly evenly distributed throughout the study area on both sides of the river, except in
areas of steep slopes. Several medium sized to small depressional wetland features are located on
the high plateau above and north of the upper cataract, which has been identified as the most likely
site for a hydroelectric project.
7. SUB-REGIONAL ENERGY DELIVERY OVERVIEW
While the primary intent of the scope of work is to assess and prioritize the hydroelectric power
potential of the four riversheds, the assessment team also reviewed sub-regional diesel power
infrastructure, bulk fuel infrastructure needs, and other local renewable energy options. The intent of
this section is to provide a discussion of how an integrated energy and power delivery system can be
achieved that can maximize the integration of a renewable energy resource and potentially minimize
the cost of additional infrastructure through the strategic design and construction of interties.
• Rural Power System Upgrades and Bulk Fuel. Currently, AVEC's power-plant in Shungnak provides
all electrical power to the community of Kobuk through an intertie between the two communities.
Although there are some needed upgrades to this intertie, it is assumed that Kobuk's power will be
provided by the Shungnak AVEC power-plant. Both the Shungnak and the Ambler diesel power
plants and bulk fuel facilities are in need of upgrades and modernization and are currently on the
AEA/Denali Commission prioritization list. A conceptual design for the RPSU/Bulk Fuel Upgrades was
completed by NANA Pacific in 2007. Furthermore, to maximize hydroelectric and other renewable
energy potential and to minimize the need to construct an additional power plant and
infrastructure, we recommend designing and constructing an intertie system between Shungnak
and Ambler. If this proposal is adopted, Shungnak could be the location of primary power
generation and bulk fuel facilities with back-up power/bulk fuel located in Ambler and Kobuk.
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Cosmos Hills Technical Review and Assessment of Alternatives
• Wind Energy Potential. In June 2008, a reconnaissance assessment was done to assess the potential
of wind energy in the Cosmos Hills area, undertaken by NANA Pacific and V3Energy. The results of
this reconnaissance trip identified several wind sites in relative close proximity to both Wesley Creek
and the Kogoluktuk Rivershed. The results of this reconnaissance trip have been plotted on the
figure below and labeled as "Potential Wind Site." We recommend further modeling of these wind
sites, identifying other alternative sites wind sites in closer proximity to Wesley and the Kogoluktuk,
and deploying met towers in several select locations, preferably at sites with an incrementally
higher elevation than the surrounding villages.
• Woody Biomass Potential. An Upper Kobuk Woody Biomass Study is underway that could work
synergistically with a conceptual hydroelectric generation facility for the benefit of the villages.
Phase 1 (pre-feasibility) of the Upper Kobuk Biomass Feasibility Study was completed in August 2008
by NANA Pacific. WHPacific completed Phase 2 in the Summer of 2011. Preliminary results prove the
concept to be biologically sustainable and economically feasible. The aim of the project is to study
the feasibility of implementing a wood-fired biomass system. The studies include a variety of system
scales, from the individual woodstove level up to a district heating system. Such a system would
potentially serve residential and commercial building heating needs, and peak months would be
during the winter months between October and May. A hydro-powered heating system would
compliment a biomass system by providing energy during the low-heat-demand summer months.
More detailed analysis is needed to assess the heating needs of the sub-region and how woody
biomass and hydroelectric power could synergistically address thermal heating needs for the sub-
region.
13
WBPailfi(
Cosmos Hills Technical Review and Assessment of Alternatives
Sub-Regional Power Delivery
System Conceptual
Hydroelechic, Diesel Power, Biomass, and \/VInd Energy
Alaska Village Electric Cooperati ve
.6. Intake -Existing Power line
0 SUrvey Area -Penstock
• Powemouse -Power line
• Potential \/VInd Site
Figure 5 Sub-Regional Power Delivery System Conceptual
14
Cosmos Hills Technical Review and Assessment of Alternatives
8. SUB-REGIONAL THERMAL HEATING NEEDS
As discussed in a previous section, the Kogoluktuk River has the potential to provide electricity for
thermal heating by shaping generation to meet demand for the communities of Ambler, Shungnak, and
Kobuk throughout the year. Thermal heating needs as delineated below can help frame the fuel
switching discussion and how the Kogoluktuk River could potentially address thermal heating needs.
• Ambler. Commercial energy systems capacity in Ambler totals 6,136 thousands of BTUs per hour
(MBH) or 6,136,000 BTUs per hour. In addition to the homes in Ambler, there are five medium-large
commercial facilities. The largest facility is the school. In addition to this, 10 residential homes are
included in the proposed system design. Ambler also has 75 occupied housing units that utilize an
estimated 60,000 gallons of fuel per year.
• Kobuk. Commercial energy systems capacity in Kobuk totals 1,096 MBH or 1,096,337 BTUs/hr. In
addition to the residences in Kobuk, there are four medium-large commercial facilities and the
largest facility is the school. Kobuk has 36 occupied homes that utilize approximately 29,000 gallons
of fuel per year.
• Shungnak. Commercial energy systems capacity in Shungnak total 3,118 MBH or 3,118,000 btu/hr.
In addition to the residences in Shungnak, there are four medium-large commercial facilities, with
the largest facility being the school. Shungnak has 62 occupied houses and utilizes approximately
50,000 gallons of diesel fuel per year.
9. RECOMMENDED NEXT STEPS
To advance AVEC's evaluation of hydroelectric potential in the Upper Kobuk Region, WHPacific and its
team members have the following recommendations:
• Complete hydrologic data collection and update hydro-electrical modeling using hourly data for
Wesley Creek and Kogoluktuk River.
• Decommission hydrologic monitoring stations on Cosmos and Dahl Creeks and re-use the equipment
to supplement data collection on Wesley Creek and the Kogoluktuk River through the canyon reach.
• Initiate a winter flow monitoring program on the Kogoluktuk River to define winter flow conditions
and discharge rates and further develop the stage-discharge curve.
• Complete environmental assessments (fisheries, wetlands, etc.) in support of the Wesley and
Kogoluktuk sites.
• Complete geologic studies and permafrost mapping in support of the Wesley and Kogoluktuk sites.
• Determine suitable compensation flow for the diversion reach of Wesley Creek.
• Assess the cost/benefits of a dam storage facility and required design and permitting information for
the Kogoluktuk River.
• Initiate contact with turbine and generator suppliers to further refine the cost estimate.
• Refine cost estimates for sites and reassess project economics through additional design and
associated cost estimates.
• Undertake a more detailed thermal heating analysis and determine how fuel switching from
"heating fuel" to electric energy derived from hydroelectric power could be undertaken.
• Undertake a wind & met tower feasibility study on the higher elevation sites in closer proximity to
Wesley Creek and the Kogoluktuk River.
• Review the results of this technical memorandum with project stakeholders.
15
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