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HomeMy WebLinkAboutCosmos Hills Hydroelectric Feasibility Preliminary Assessment & Technical Memorandum - Oct 2011 - REF Grant 2195413AYEC�� j October 24, 2011 Audrey Alstrom Alaska Energy Authority 813 Northern Lights Boulevard Anchorage Alaska 99503 Re: Cosmos Hills Hydropower Study Grant 2195413 Cosmos Hills Hydropower Study: Technical Assessment and Technical Memorandum Dear Audrey_ With funding received from the Alaska Energy Authority's Renewable Energy Fund (REF) program, Alaska Village Electric Cooperative (AVEC), and its consultants, has prepared the Cosmos Hills Hydropower Study: Technical Assessment and Technical Memorandum (attached). This report documents the rationale used to narrow down the Cosmos Hilts hydroelectric alternatives. As a preliminary study, this report summarizes best professional judgment of alternatives based on available hydrology data, design considerations, geotechnical conditions, wetlands and fisheries conditions, and regional energy delivery options. For this report four potential hydroelectric sites that could serve the communities of Kobuk, Shungnak, and Ambler were evaluated. These include Dahl Creek, Wesley Creek, Cosmos Creek, and the Kogoluktuk River. Based on hydrologic investigations and field observations of elevation, geology and natural hazards some of the assumptions have changed from earlier expectations. Based on the work, we determined that hydropower sites on Wesley Creek and the Kogoluktuk River appear to be technically and environmentally feasible and are recommended for further study. With estimated capacities ranging between 428 kW and 950 kW, these two projects are the most appropriately scaled for the energy needs of the communities and future development in the region and are located relatively close to existing communities and power line infrastructure. We appreciate the comments that we have received from you on the report. Please feel free to call or email me if you have any questions on the report. Sincerely, Brent Petr!e Manager, Community Development and Key Accounts Attachments: Cosmos Hills HYdropower Strcy: Technical Assessment anti Technical Memorandum 831 �.�t1LE ti`iF�LE`C _4 ANCfst�R.1C;)r, ALASItA PHON1 01D7) 561-1818 '° FAX i.9t17i 5C2 4086 e Ii Cosmos Hills Hydroelectric Feasibility Project Preliminary Assessment& Technical Memorandum Prepared for: Alaska Village Electric Cooperative 4831 Eagle Street Anchorage, Alaska 99503-7497 Prepared by: WHPacific, Inc. 300 W. 31st Ave Anchorage, AK 99503 www.whpacific.com Funded in part by: Alaska Energy Authority Renewable Energy Fund Grant #2195413 °C.,Le 12 This memo was jointly prepared by WHPacific and NANA Worley Parson in close consultation with AVEC and Solstice Consulting. Team members and contributors include; • Ross Klooster, PE, Project Manager/Electric Engineer, WHPacific; 4 Cella Rethamel, PE, Civil Engineer, WHPacific; Jay Hermanson, Program Manager/Energy Specialist, WHPacific; • Steve Buckley, Geologist/Hydrologist, WHPacific; Phil Quarterman, Environmental Scientist, WHPacific; • Stuart Parks, PE, Executive Sponsor, NANA Worley Parsons; • Matthew T. Schuett, MASc, Project Engineer/Hydroelectric Specialist, NANA Worley Parsons; Michael Lilly, Hydrologist & Stream Gauging Specialist, GWScientifc; • Dave Brailey, Hydrologist, Brailey Hydrologic; • Robin Reich, Solstice Alaska Consulting; • Brent Petrie, Community Development Manager, Alaska Village Electric Cooperative. Additional contributors include Steve Noble, PE with DOWL HKM, Sonny Adams, NANA Regional Corporation, Jeff Nelson with NANA Regional Corporation, Nicole McCulough with WHPacific, and Elia Sakeagak with WHPacific. NAW WorleyParsons W]INCIfic IFr. 13 1. OVERVIEW This technical memorandum presents the results of the WHPacific team's review and assessment of hydroelectric and sub -regional power alternatives in the Cosmos Hills. This technical review was conducted between July and September of 2011 and involved a multi -disciplined team. In the previous Cosmos Hills Hydroelectric Reconnaissance Report prepared for this project, hydroelectric alternatives in the Cosmos Hills area near Kobuk, Shungnak, and Ambler were investigated. Four alternatives were carried forward for further study including the Kogoluktuk River, Wesley Creek, Cosmos Creek and Dahl Creek. During the summer of 2010, field wetlands, fisheries, geotechnical studies and office -level cultural studies were conducted on creek alternatives. Aerial photography, LIDAR and hydrological field studies were conducted on the creek alternatives and on the Kogoluktuk River. The results of the work was documented in the Summer-F6112010/3pring 2011 Fieldwork Report. Hydrology work continued through the summer/fall of 2011. After collecting one year of hydrological data, AVEC concluded that adequate information was available in order to determine the best hydroelectric project alternatives to carry forward for a more detailed investigation. This report documents the rationale used to narrow down the Cosmos Hills hydroelectric alternatives. As a preliminary study, this report summarizes best professional judgment of alternatives. A final hydrology report, to be completed by December 2011, will provide more detailed information. In addition, this report provides preliminary information from studies conducted on the alternatives carried forward for more study, including design considerations, geotechnical conditions, wetlands and fisheries. The final geotechnical, wetlands and fisheries reports will be provided in December, 2011. Finally, this report includes information on regional energy delivery options. The analytical framework enabled the team to assess the Cosmos Hills alternatives during the summer months, enabling the opportunity to modify the field study methods before winter. 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 included Cosmos Creek, Wesley Creek, Dahl Creek and the Kogoluktuk River, as shown in the map below. NANA Wod&VPArsons 'Wil 1�C 4-_, 14 c—^�--c----r of .shun rtak Ripe {In Xog6luk�6k Ri era sm .0 aIf �©aihC @i - - 'APR � •. � .... _ .. .. C w - n ,�'s" 4 w�.-' � S �3 pit'ObUK r Hydroelectric Power taZ:Jint Step t" �'� Alaska village Electric cooperative I �I�gfll *tip ❑ Survey Area , intake " M1�-'W ■ Powerhouse Penstock I owil n-O„4,Zav 7N 'Y?tteDes V HPacific 0 ` 2. 4 ! �� 6 USGS figu'IaR 7:t0 UOO See 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 at 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. � WHPacc worieyPa.sons �5 102 4t 98 m =3 97 0 as Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug 2010 2011 Upper Cosmos Creek Gauging Station j — om" water Elevation • Carihralion Data QAOCDira Avalanche Snow Drift Flooding tee Affected i Upper Wesley Creek Gauging Station 93.0 _ Ebvali_ Pit Waror oa — 92.8 — +�— Calihraliotr Data 2' OAQC Data 9zs 92.4 922 920 C 91.8 t 91.6 • ° 91.4 m � 91.2- rb 91.0 , 90.8 Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug 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 and Dahl Creeks and on the Kogoluktuk River from mid -October to mid -May and to a lesser extent on the Wesley Creek. Water temperature records suggest Wesley Creek may have a larger groundwater component that delays or prohibits the formation of solid ice cover. This 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 -discharge 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 flow measurements completed and referenced to a fixed survey datum. Due to the suspended sediment concentrations and water velocities during breakup and winter ice issues experienced at the Kogoluktuk site, only four Acoustic Doppler Current Profile (ADCP) measurements were available for the development of a preliminary stage -discharge curve prepared for this report. Due to the low confidence in a stage -discharge 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 the drainage area were used to estimate monthly average flown values. Figure 3 shows the stage -discharge curve developed for Wesley Creek. w Wi�P dfi vtrorf•„�rean8 '_ €; 16 Wesley Creek Stage -Discharge Curve 92.00 ,__T __T 911.90 —Calculated Data _ Measured Data $ 91.80 E e 91.70 Y � I + at 9160 - t I N = 91.50 — 91.40 - Y N 92.30 — 91.20 j 91.10 I 91.00 0 Q= 4.2933 (Stage - 94.12)5-6907 I _— I I I 25 50 75 100 125 150 Flow (efs) Figure 3: Wesley Creek Stage -discharge curve developed from August 2010-2011 data 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 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 power from a site the following equation is used: P=)7gQH Where: P = Power in kW rl = efficiency (65 — 90%, Note: smaller units tend to have lower efficiency ratings) g = gravity (9.81 m/sZ) Q = flow (m3/s) H = height (m) Using the updated flow and elevation data, the four sites were reassessed. Table 1 provides a summary of the reassessment. wr• Nnraa NbrleyParsona W INC-ffi Table 1: Summary of potential hydroelectric sites in the Upper Kobuk region Hydroelectric site Drainage area, sq. mi. Installed capacity, kW Est. net head, ft. Est. hydraulic capacity, cfs # of units Turbine type Initial Estimate 2010 Dahl Creek 9 430 220 35 1 Crossflow Cosmos Creek 13 950 290 50 1 Vertical Pelton Wesley Creek 6 480 300 25 1 Pelton or Turgo Kogoluktuk River 290 3,200 57 800 2 Francis Updated Information 2011 9 13 I 6 290 _ 18_� #t?8 _ �_' 9 - 120 350 YM 41 25 ' : ' 21 425 Dahl Creek 1 Crossflow Cosmos Creek 1 Pelton or Turgo Wesley Creek 1 Pelton or Turgo Kogoluktuk River 2 Kaplan Summary Table Colour Legend Significant Reduction (>50%) Reduction (0-50%) Increase Dahl Creek has a lower -than -expected elevation difference between the intake and powerhouse locations, and therefore the site's potential generation is reduced to a value below the peak village demand of Shungnak and Kobuk. Based on the above information, AVEC is not recommending Dahl Creek for further consideration. Flows were also lower than expected within the Dahl Creek valley, although it is noted that 2011 has been below the previous 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 if electrical demand supports such an initiative. Wesley Creek is recommended for further consideration by AVEC, having the least amount of change from the original estimated values. 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. The station collects data on the Kogoluktuk River during winter months, and the Kogoluktuk River was shown to have flowing water under the ice all winter. However, sensors that were frozen into the river ice were w' WHPacc NAMA WodeyParsons ripped out during breakup. Changes in icing conditions on the river (cold and warm spells) created complex stage height records typical of ice -covered rivers. Additional flow monitoring and modification of the existing water level data collection system is recommended to gain a better understanding of both summer and winter flows in the Kogoluktuk River. While the flow dataset used for the 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 the 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 / score ranked 1 (worst) to load/existing capacity, to installation hydropower capital cost 5 (best): power line service per kW generation and road existing elec. season access demand Wesley Creek 5 4 3 4 5 4.2 Dahl Creek 5 1 2 3 3 2.8 Kogoluktuk River 2 2 5 4 1 2.8 (run -of -river) Cosmos Creek 1 3 3 1 2 3 2 2.6 As shown in Table 2, Wesley Creek appears to be the most attractive economically and environmentally 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. Figures 4, 5 and 6 show the potential generation from a hydroelectric development on the respective creeks/rivers compared to the electrical demand from Shungnak and Kobuk (S-K), as well as Ambler, Shungnak and Kobuk (A-S-K). This is for current electrical (power -generation) demand only. \01111/ Mff ffi WorleyParaons 19 Wesley Creek Resource Supply/Demand Comparison 700 .500 3 9on x F� M u w 200 100 1-Jan 31 Jan 2-Mar 1-Apr 1-May U-May 30-Jun 39-Jul 29-Aig 1Vep 28.0c: 27-Nov 2;-Dec ? Date (ddimmm) Figure 4: Wesley Creek Resource Supply/Demand Comparisons Dahl Creek Resource Supply/Demand Comparison 700 "A 9 500 s_ _T Q Q N 400 C� C d 0 300 'u 100 1-Jan 114an 141ar I - Apr I -May 31-Mav JOJun 504ul 29-Aug A -Sep 18-v4t il-Noi 11-Dec Date (ddimm ml Figure S. Dahl Creek Resource SupplyjDemand Comparison YYodeyParsons 'WHN .C-I 110 Cosmos Creek ResourceSupply/Demand Comparison 600 v W I00 1J:n i1J:n 2aNa• 1-A3r 1May 31AUV 304un 30Ju1 29-Aug A -Sep 23=Oct 27-Nov 17-Dac Date (ddimmm) Figure 6: Cosmos Creek Resource%Supply Comparison 3. DESIGN CONSIDERATIONS Site investigations were initiated following the 2010 reconnaissance study identifying the four potential hydroelectric sites for further evaluation. The focus of these investigations was to determine if the sites identified were suitable for further analysis and potential development. The evaluations were done by confirming model values used for flows and elevation difference in the field. 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. All four sites have had an environmental and geotechnical reconnaissance field assessment done. The information below summarizes the data that has been collected and expands on the design considerations outlined in WHPacific's 2010 reconnaissance report, which recommended further study of the Wesley, Cosmos and Dahl Creeks and the Kogoluktuk River. Based on the outcome of the hydroelectric assessment presented previously, the focus of this section is on the 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 has not been determined. The degree of degradation caused by the weathering is unknown at this time a nd therefore has the potential to increase costs if competent material cannot be found close to the surface. W Miles"On. Wff adf1C ,'aL e , 11 Until the site is fully assessed by a drill program or is constructed, the geotechnical aspects of a site tend to remain the largest risk component in a design. Due to the high costs of utilizing a drill program, which 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 the refusal may not have been caused by permafrost but a frozen active layer. Permafrost is discontinuous in several areas along the creek and further mapping in the area of the 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 of the penstock to reduce material 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 the ground conditions encountered. Powerhouse- Civil. The area has limited seismic activity, magnitude 4 to S. 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 for the 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'. Based on the outcome of the hydroelectric assessment, a detailed geotechnical investigation is recommended for Wesley Creek in the vicinity of the powerhouse. If the depth of the permafrost and/or the bedrock can be determined, then other foundation systems may be more feasible or more cost effective. • Powerhouse- Electrical/Mechanical. Turbine and generator manufacturers should be contacted to determine the best generation option according to the specific site conditions at Wesley Creek. 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 flood pla i n/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 ' See page 15 of Golder Report wbrl®yrPareans Fad; 12 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 a study to provide access to Ambler (Ambler Access study). This study has the potential to benefit acoess to these sites through an improved and coordinated effort. 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. A summary of this field work is provided below; a more in-depth design consideration section will be developed once the geotechnical report has been completed for the Kogoluktuk River. 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. 4. 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. NANA Worlevftrsons Wfiil if c i��P, 113 • 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 eoiian 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 ohannel along the lower reaches of Wesley Creek should be expected in isolated areas. 4 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 of the 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. Typically, due to the granular nature of the soils and larger void spaces associated with larger -diameter deposits, permafrost soils would include \011/ MIPd(M WorleyParsons a deeper active layer depth, if permafrost is present. large-scale indications of slope instabilities were not observed on the valley side slopes. Small localized areas of talus and colluvium exist at steeper slope areas. S. 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. This report, which was funded by NANA Regional Corporation, 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 Kogoluktuk 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. It now includes an additional cataract downstream, extending the study area by about 1.2 air miles. The study area was shortened at the upstream end by about 0.9 air miles, 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 the study to assess potential anadromous fish habitat and barriers to fish passage. • 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. If the downstream cataract were passable, then the upstream cataract is likely passable as well. 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), of which includes 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. Fish were generally collected along the margins of the river. A tributary enters on the river near the center of the middle reach. The upstream end of the sampled area was 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 carried out 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 NW NAN/% WorleyParsons WHPaC1fiC Pa ,4 115 potential salmon presence, carcasses, redds and suitable spawning habitat. Despite the availability of suitable spawning substrate and habitat, salmon presence or use was not observed. In addition, grayling in the reach was not observed either despite the presence of a 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. Three broad classes of wetlands were identified: floodplain areas adjacent to ordinary high water line on the Kogoluktuk River, localized depressions on the terrace above the river and broad hill slopes. The position of each of these features was recorded using a hand-held GPS unit, with photographic records and notes made on vegetation and hydrology. 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. A number of streams were identified in addition to the Kogoluktuk River, including the 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 wetlands, the assessment team concluded 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. 6. 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 utilized to maximize the integration of hydroelectric power 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, the AVEC power plant in Shungnak provides all of the electrical power to the community of Kobuk through an intertie. Although there are some needed upgrades to this intertie, it is assumed that Kobuk will continue to be powered 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. A conceptual design for the RPSU/Bulk Fuel Upgrade Project 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, design and construction on an intertie between Shungnak and Ambler is recommended. If this proposal is adopted, Shungnak could be the location of the primary power generation and bulk fuel facilities, with standby power modules located in Ambler and Kobuk. W IWIR. CI�C atIAN!' WorfeyParsons 16 Wind Energy Potential. In June 2008, a reconnaissance assessment was done to evaluate 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 "Potential Wind Site." Further modeling of these wind sites, identifying other alternative sites wind sites in closer proximity to the Wesley Creek and the Kogoluktuk River is recommended. It is also suggested to deploy 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 i (pre -feasibility) of the Upper Kobuk Biomass Feasibility Study was completed in August 2008 by NANA Pacific. WHPacific prepared 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, with peak power requirements occurring 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 cf the sub- region and how woody biomass and hydroelectric power could synergistically address thermal heating requirements. NAO�l___ NANA Worleyftrsons WHPWC fft co 0. T # Li ! Q% d R m /�1 +fit i Y F 7 t 3 V vyi o. c 3 0 o x d o 1' 1. a 1 m1 O U LLI Q a _ E ts lee -''�{,` F 04 O +4+ �° 9 d i� O N G / m ! t waD AL X 44. ..i - � t15�+ • 'i, :.v, � F.W' 'I ter,% � }, .. di m / 3 a r �' sLL H r ooII0.7 N m aa' y 0 0 0 IL a- i b ' z -14. ..-_.f.. tE e1 1$ 7. 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. 4 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, the largest 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, the largest is the school. Shungnak has 62 occupied houses and utilizes approximately 50,000 gallons of diesel fuel per year. H. RECOMMENDED NEXT STEPS To advance AVEC's evaluation of hydroelectric potential in the Upper Kobuk Region, WHPacific proposes 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. • Perform 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. • Complete a more detailed thermal heating analysis and determine how fuel switching from "heating fuel" to electric energy derived from hydroelectric power could be undertaken. • Perform 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. � WHFacific rle„Parson$ WHPac�fic 300 W 31st Ave Anchorage, AK 99503 907-339.6500