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HomeMy WebLinkAboutKnutson Creek Hydroelectric Reevaluation Report - Jun 2016 - REF Grant 7060976polarconsult alaska, inc. 1503 West 33rd Avenue, Suite 310 Anchorage, Alaska 99503-3638 Phone: (907) 258-2420 FAX: (907) 258-2419 L E T T E R R E P O R T 160630M-PEDROBAYHYDROREEVALUATION.DOC DATE: June 30, 2016 TO: John Baalke, PBVC Administrator FROM: Joel Groves, PE Polarconsult Project Manager SUBJECT: Project Size Reevaluation for Knutson Creek Hydroelectric Project CC: David Lockard, AEA Project Manager 1.0 INTRODUCTION, PURPOSE, AND SUMMARY OF FINDINGS 1.1 Introduction and Purpose The Alaska Energy Authority (AEA) awarded a grant to the Pedro Bay Village Council (PBVC) for design and permitting of a run-of-river hydroelectric project (project) on Knutson Creek. PBVC hired Polarconsult Alaska, Inc. (Polarconsult) to complete design and permitting for the project. As a precursor to commencing full design and permitting of the project, the AEA requires that the PBVC reevaluate the project size and layout due to concerns about the village’s population and future energy demand. Polarconsult recommended that this reevaluation be deferred until key permit conditions were better-defined, as the permit conditions would also have a significant impact on the project. This letter report presents the project reevaluation based on consideration of the following: 1. Current Knutson Creek hydrology data, 2. Current electric utility load data, 3. Current village population data, 4. Better-defined permit conditions for the project, and 5. Analysis of project size based on technical and economic considerations. 1.2 Summary of Findings Pedro Bay population and electric utility load have both increased slightly since the feasibility study was completed in 2013. More recent hydrology data is consistent with the hydrology data used for the feasibility study analysis. Progress to date on key project permits supports the permit assumptions in the feasibility study. These data, presented in Section 2 of this letter report, support the data and assumptions used in the feasibility study to size the hydro project. A more detailed analysis of the project size was performed to complete the reevaluation. Technical and economic factors were reviewed and some of the assumptions in the feasibility study modified to determine the optimal project size. First, the minimum project size required to meet existing utility demand was defined, then incremental project costs and benefits were evaluated for incrementally larger projects to determine what project size was economically justified under existing and reasonable future utility load conditions. Based on the reevaluation analysis, presented in Section 3 of this letter report, the optimal project uses a 24-inch diameter penstock to generate approximately 150 to 200 kW of electricity. The final size will vary depending on final project design, and in particular on final penstock design and final efficiency of the turbine/ generator system. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to Pedro Bay Village Council Polarconsult Alaska, Inc. June 30, 2016 Page 2 of 12 The recommended project is estimated to displace 98.4 percent of the diesel fuel consumed by the electric utility annually, and also displace 14,600 gallons of heating fuel used in four community buildings (approximately 80 percent of their annual usage).1 1.3 Background Polarconsult previously completed reconnaissance and feasibility studies for the hydro project in 2009 and 2013, respectively.2 The general project configurations recommended by these studies and the current reevaluation are summarized in Table 1. Table 1: Previously and Currently Proposed Hydro Project Configurations Source Installed Capacity1 Total Annual Hydro Generation Estimated Installed Cost Percent of PBVC Load Met by Hydro 2010 Recon. Study 200 kW 1,668,000 kWh $2.5M (2009$) 100% 2013 Feas. Study 200 kW 1,503,700 kWh $4.5M (2013$) 95.6% Current Reevaluation 195 kW (150 - 200 kW) 1,514,900 kWh NA 98.4% 1. The reconnaissance study considered 125 and 200 kW projects. The feasibility study considered a range of project capacities from 100 to 250 kW, with 200 kW having the highest benefit-cost ratio. 2.0 CURRENT COMMUNITY AND PROJECT INFORMATION 2.1 Hydrology Two stream gauging stations are maintained on Knutson Creek approximately 1/2 mile downstream of the proposed diversion site. These gauging stations are described in Appendix C of the feasibility study. Polarconsult has reviewed additional hydrology data collected since 2013. Analysis of available hydrology data indicate flows in Knutson Creek are reasonably consistent with the hydrology model used for the feasibility study and development of an updated hydrology model is not warranted at this time. The reevaluation presented in this memo is based on the existing hydrology model. 2.2 ECUC System Electric Load at Generation As shown in Figure 1 and Table 2, annual PBVC load has been stable at approximately 188,000 kilowatt-hours (kWh) since 2013. From 2010 to 2013, PBVC load experienced a 10% year-over- year decrease for three straight years. This load decrease is attributed to closure of the school in fall 2011 and associated community impacts. Prior to 2010, annual load was stable at approximately 260,000 kWh. The significant load decrease experienced from 2010 to 2013 is understood to be a key factor in AEA’s requirement for this project review checkpoint when the design and permitting grant was awarded in 2014. Annual load since 2013 has increased slightly, with 2015 annual load of 1 The analysis also includes dispatch of electric heat to the school and diesel power plant, but both are already served by a waste heat loop from the diesel power plant, so this electric heat service is not included in the project benefits. 2 Polarconsult, 2009; Polarconsult, 2013. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to Pedro Bay Village Council Polarconsult Alaska, Inc. June 30, 2016 Page 3 of 12 0 10 20 30 40 50 60 70 80 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Peak Monthly Generation (kW) Average Monthly Generation (kW) 194,160 kWh 6.5% higher than in 2013. The feasibility study was based on an annual utility load of 182,200 kWh.3 Future load will fluctuate with the local economy as people and families move to and from Pedro Bay in accordance with their desire to live in and ability to make a living in the village. Figure 1 and Table 2 present historic utility load and related data from 2003 to 2016. Figure 1: Average Monthly PBVC Electric Utility Load 4 3 Feasibility Study Final Report, Table ES-2. Polarconsult, 2013. 4 2003 to 2013 data are from 2013 Feasibility Study. Polarconsult, 2013. 2013 to 2016 data are provided from the Power Cost Equalization program reports prepared by PBVC. AEA, 2016; PBVC, 2016. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 4 of 12 Table 2: Annual PBVC Electric Utility Information Data from 2003 to 2013 is from 2013 Feasibility Study. Polarconsult, 2013. Data from 2013 to 2016 is compiled from monthly Power Cost Equalization program records prepared by PBVC. AEA, 2016; PBVC, 2016. (1) Data for 2003 include July through December. (2) Data for 2016 include January through May. (3) Rates are for “average residential rate for 500 kWh/month consumption”, compiled from annual Statistical Report of the PCE Program, published by the AEA. Each report covers the state fiscal year (July 1 of the preceding year to June 30 of the calendar year). All other data in this table is based on calendar years. ‘–’ denotes data that are not available or not meaningful due to incomplete records. NA Not available. Parameter 2003 (1)2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 (2) kWh Generated 102,314 249,083 295,974 272,211 264,939 262,759 256,409 256,677 226,996 203,953 183,744 186,037 194,160 72,815 kWh for Station Service (% of total generation) 5,257 (5.1%) 10,411 (4.2%) 14,239 (4.8%) 14,474 (5.3%) 12,112 (4.6%) 12,217 (4.6%) 12,222 (4.8%) 12,299 (4.8%) 11,718 (5.2%) 10,793 (5.3%) 13,119 (7.1%) 14,694 (7.9%) 12,433 (6.4%) 4,844 (6.7%) kWh Sold 85,778 212,284 246,953 237,475 232,618 231,273 233,755 236,982 200,942 174,562 153,126 151,790 163,428 60,709 Fuel Price (annual average) $2.24 $2.57 $2.74 $3.04 $5.06 $6.14 $4.60 $4.56 $5.23 $5.78 $5.81 $5.18 $4.46 $3.84 Fuel Used (gallons) 10,403 23,349 22,552 19,454 20,325 23,458 21,018 21,673 19,514 20,583 18,284 17,098 18,783 6,779 Total Fuel Expense $23,321 $60,121 $61,798 $59,181 $102,886 $144,133 $96,669 $98,880 $102,132 $118,974 $106,247 $88,599 $83,770 $26,063 Total Non-Fuel Expense $18,870 $41,233 $47,015 $41,811 $38,664 $44,833 $44,696 $53,855 $52,248 $34,539 $35,428 $38,365 $43,771 $14,864 Total Utility Expense $42,190 $101,353 $108,814 $100,992 $141,550 $188,966 $141,365 $152,735 $154,380 $153,513 $141,675 $126,964 $127,540 $40,927 Power Cost per kWh $0.492 $0.477 $0.441 $0.425 $0.609 $0.817 $0.605 $0.645 $0.768 $0.879 $0.925 $0.836 $0.780 $0.674 Unsubsidized Electric Rate per kWh (3) $0.600 $0.600 $0.600 $0.600 $0.600 $0.600 $0.910 $0.910 $0.910 $0.910 $0.910 $0.910 $0.910 $0.910 Generation Efficiency (kWh/gal) 9.8 10.7 13.1 14.0 13.0 11.2 12.2 11.8 11.6 9.9 10.0 10.9 10.3 10.7 Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 5 of 12 2.3 Pedro Bay Population Trends Historic and current population of Pedro Bay is presented in Table 3. Population has been reasonably stable for the past 25 years at between 42 to 50 people. Current estimates indicate a population increase of approximately 12 percent since the feasibility study was completed from 42 to 47 people. Table 3: Historic Population Data Year Population 1 1950 44 1960 53 1970 65 1980 33 1990 42 2000 50 2010 42 2011 47 2 2012 42 2 2015 47 2 Future Projection 30 to 70 NOTES: (1) Population data for 1950 through 2010 is from the Feasibility Study (Polarconsult, 2013). (2) 2011 through 2016 population is from the Department of Community and Regional Affairs (DCRA) census. 2.4 Permit Terms and Conditions The feasibility study identified Federal Energy Regulatory Commission (FERC) jurisdiction over the project and Alaska Department of Fish and Game (ADFG) fish habitat permit conditions as key permitting factors that would influence project performance and/or economics.5 At the recommendation of Polarconsult and concurrence of PBVC and AEA, these two permits have been advanced to provide better information for this project reevaluation. 2.4.1 FERC Jurisdiction FERC jurisdiction over the project would result in a significant increase in both project development costs and long-term project operation and maintenance costs. To determine if FERC would assert jurisdiction over the project, a Declaration of Intention (DI) was filed with FERC in July 2014. Upon consideration of comments on the DI filed by PVDC and ADFG, FERC ruled that the project was not under FERC jurisdiction in September 2015.6 This is the outcome assumed in the feasibility study, and is a beneficial outcome for the project. 5 Polarconsult, 2013 at page iii. 6 FERC, 2015. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 6 of 12 2.4.2 ADFG Fish Habitat Permit Existing information and field surveys completed during the feasibility study indicate the presence of both anadromous and resident fish within the proposed bypass reach of Knutson Creek. Accordingly, a fish habitat permit is required for the project to address anadromous fish impact. In order to define the permit terms and conditions, Polarconsult initiated the permit process with ADFG. A pre-application meeting was held in February 2016, and a fish habitat permit application was filed with ADFG in March 2016. A follow-up meeting was held in May 2016. Based on these consultations, the main fish resource question is whether sockeye salmon successfully spawn in the bypass reach of the creek. Available spawning habitat occurs in gravel and cobble bars located on the lateral fringes of the stream. These bars may be dewatered during naturally-occurring winter low flows. Adult sockeye may lay redds in these bars, but there is a possibility that the redds dry out or freeze and die over the course of the winter. Polarconsult will conduct spawning surveys in August 2016 to identify the three best spawning sites in the bypass reach, and then characterize the stage-discharge curve at each site to ascertain whether the spawning sites are dewatered under typical winter hydrology. The findings of this study will guide the need for and amount of in-stream flow reservations in the bypass reach. While ADFG permit terms have not been finalized, discussions to date indicate that the 6.6 cfs In Stream Flow Reservation (ISFR) assumed in the feasibility study is still a reasonable estimate. This reevaluation uses the same assumed 6.6 cfs ISFR used in the feasibility study. 3.0 PROJECT REEVALUATION Project layout and installed capacity is reevaluated to determine the appropriate project configuration and size for the community. 3.1 Reevaluation of Project Layout Conceptual design drawings for the project were included in the feasibility study. These drawings were developed using an existing LiDAR survey of the project site augmented with limited topographic surveys and other field work completed during the feasibility study. 3.1.1 Diversion Location The diversion location is well-defined by topography, hydrology, and surficial geology. No alternate diversion locations were considered for this reevaluation. 3.1.2 Powerhouse Location The general powerhouse site is well-defined by topography, but there is some latitude for adjustment of the specific location. The existing drawings have the powerhouse sited near the upper end of Knutson Creek’s alluvial cone, with a finish floor elevation of 178 feet. Upon review, the powerhouse could be moved upstream approximately 350 feet or downstream as far as the mouth on Iliamna Lake. The grade of the terrain in the powerhouse vicinity is ~4%. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 7 of 12 Moving the powerhouse upstream 350 feet would reduce project head by approximately 15 feet and reduce the tailrace length from approximately 1,400 feet to 500 feet. Review of the incremental benefits and costs of this move indicates it is approximately neutral to project economics, with construction cost savings approximately equal to the present value of lost generating capacity.7 Moving the powerhouse downstream appears to have more negative than positive impacts, and was not reviewed in detail. Benefits include increased project head and generating capacity for a given design flow. Potential costs include increased penstock and tailrace length, increased impact to likely productive salmon habitat in the lower reaches of Knutson Creek, and increased exposure of the powerhouse site to long-term flood or erosion hazards from Knutson Creek’s meanders across its alluvial cone. Based on these considerations, the powerhouse location was not changed for this reevaluation. 3.1.3 Other Project Elements The locations of access roads, portions of the penstock, and the tailrace are not well-defined by technical criteria, and may be adjusted in final design based on non-technical criteria such as community and/or land owner preference, environmental factors, permit terms and conditions, and project cost. The range of probable alignments for these features is not expected to have a significant impact on project economics, so they are not considered in this reevaluation. 3.2 Reevaluation of Project Size Reevaluation of project size requires consideration of the turbine/generator capacity and directly dependent project attributes, including the intake works, penstock, transformer, and general powerhouse dimensions. Project elements that are largely independent of size (within the range of sized considered for this reevaluation) do not need to be considered. These include the diversion structure, access roads, tailrace, controls, switchgear, primary power line, communications, and plant integration. The methodology used to reevaluate project size follows. 1. Determine minimum project size to meet existing electric utility load. This is the base project against which larger projects are considered. 2. Estimate the incremental costs and benefits of larger projects relative to the base project to evaluate whether they are economically justified. The project design flow and size is largely determined by the size and hydraulic capacity of the penstock, so project sizes are constrained by commercially available pipe sizes. 3. Review project sizes under different load-growth scenarios to assess whether economically marginal project sizes may become economic with increases in utility load that are reasonably likely within the project’s 50-year design life. 7 This analysis only considered utilized energy under current community conditions (utility load and community building heating loads). It did not assign a value to unused but available generation capacity. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 8 of 12 4. The recommended project size is based on the largest project that is estimated to have beneficial incremental economics under reasonably likely future load growth. 3.2.1 Minimum Project Size The minimum project size is set at 75 kW. This is based on an 16-inch diameter penstock and 6.5 cubic feet per second (cfs) design flow. The minimum-sized project is determined as that which will meet existing peak utility load and also power an electric load bank governor for hydro generator voltage and frequency control in stand-alone operation. Peak load under existing load patterns is estimated at 50 kW, and the electric load bank is sized at 10 kW for a 60 kW minimum project size. The 75 kW project with an 16-inch penstock is the smallest penstock / project that meets the size criteria. A project using a 14-inch penstock would only generate approximately 45 kW, requiring frequent parallel operation of the diesel power plant to meet peak load. This would significantly reduce project benefits due to increased fuel usage for parallel diesel electric generation. 3.2.2 Estimated Incremental Costs and Benefits of Larger Projects Larger project sizes were developed based on evaluation of larger-diameter penstocks and corresponding design flow rates. Several larger projects were considered with generating capacities ranging from 90 to 345 kW. 3.2.2.1 Estimated Incremental Project Costs For each project size, incremental project costs included the following: o Installed penstock cost (considering material cost, shipping cost, and installation cost). o Installed cost of turbine-generator system. For all project sizes, the turbine-generator set is assumed to be a dual admittance cross-flow turbine driving a single-phase synchronous generator via a gear-drive speed increaser. This system is assumed to have a full-flow water-to-wire efficiency of 68% and operation under partial flow conditions down to 10% of design flow at an efficiency of 50%. o Relative incremental costs of the intake (screens and concrete), hydro powerhouse (general building dimensions), and step-up transformer (based on standard available kVA ratings). Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 9 of 12 3.2.2.2 Estimated Incremental Project Benefits To estimate incremental project benefits, each project size was run through the generation dispatch model developed for the feasibility study to estimate the incremental amount of utility load the hydro project would supply and the incremental amount of electricity that could be dispatched to interruptible electric heating systems to displace heating fuel.8 All project benefits are based on the cost savings of reduced diesel consumption at the diesel power plant and reduced heating oil consumption at public buildings fitted with interruptible electric heating systems. Benefits are converted to present worth using the current power plant fuel price in Pedro Bay of $3.84 per gallon, a 2.5% effective discount rate, and 50-year life. For this analysis, fuel costs are assumed to be fixed at the current nominal fuel price over the project life. The feasibility study concluded that all heated buildings in the village should be fitted with interruptible electric heating systems to utilize excess energy from the 200-kW project. Achieving this build-out of interruptible electric heating systems to private residences and businesses may be a challenge. For this reevaluation, the build-out was limited to five larger community buildings. This reduces project benefits, but would simplify the retrofit requirements and minimize potential issues with electric system control, utility rate structure, service line capacity, complexity of private heating systems, etc. 3.2.3 Estimated Incremental Costs and Benefits Under Load Growth Scenarios 3.2.3.1 Load Growth Scenarios Considered The analysis described in Section 3.2.2 was expanded to consider load growth scenarios that may occur over the project’s 50-year life. Three load growth scenarios were considered, and are summarized in Table 4. Results of the analysis are presented in Figure 2. Table 4: Load Growth Scenarios Considered for Economic Analysis Scenario Annual Utility Load at Generation (kWh) Discussion Base Case 182,000 Existing Load (2013 – 2016) 150% Growth 260,000 Prior Load (2004 – 2010). School reopens. 220% Growth 400,000 - 330% Growth 600,000 - The 150% load growth scenario represents a return to typical utility loads from 2004 through 2010. This load growth scenario is considered to have a very high likelihood of occurring within 8 The generation dispatch model is described in Appendix H of the feasibility study. Polarconsult, 2013. Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 10 of 12 the project’s 50-year life, especially if the hydro project lowers energy costs for the community and/or the school reopens. The 220% load growth scenario represents an increase in utility load beyond known historic trends. This level of growth would likely be associated with significantly decreased energy costs or new and expanded economic opportunities in the community. A population increase to levels last documented in the 1960s and 1970s (50 to 70 people) could also result in load growth of this magnitude. This load growth scenario is considered to have a moderate likelihood of occurring within the project’s 50-year life. The 330% load growth scenario is considered to have a low likelihood of occurring within the project’s 50-year life. Figure 2: Incremental Benefit-Cost Ratios for Project Sizes Under Load Growth Scenarios 3.2.3.2 Discussion and Findings This incremental economic analysis with load growth (Figure 3) indicates that under the 150% load growth scenario, the estimated incremental benefits of a 195-kW project using 24-inch PVC equal the estimated incremental costs, with an incremental benefit-cost ratio of 1.0. The incremental benefit-cost ratio of the 195-kW configuration improves further under higher- Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 11 of 12 0 50 100 150 200 250 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec2007 Excess Energy Available from Hydro Hydro Energy Dispatched to Community Building Heating Loads Diesel Energy Dispatched to Meet Utility System Demand Hydro Energy Dispatched to Meet Utility System Demand Current Utility System Demand Utility System Demand Met by Diesels Current Utility System Demand Hydro Energy Dispatched to Community Building Heating Loads Excess Hydro Energy Utility System Demand Met by Hydro growth scenarios, but these larger project sizes do not become economically justified (incremental benefit-cost ratio of 1 or greater) until the highest load growth scenario (+330%). Based on this analysis, the 195-kW project is the optimal size project for Pedro Bay under existing and reasonably likely future load conditions. Smaller projects would forfeit incremental net benefits under existing load conditions, and larger projects do not justify their incremental expense unless low-likelihood load growth occurs. 4.0 RECOMMENDED PROJECT CONFIGURATION The recommended project is a run-of-river hydroelectric project on Knutson Creek with an intake at RM 2.59 and a powerhouse near RM 1.25, returning water to Knutson Creek at RM 1.10 via an approximately 1,400-foot-long tailrace channel. The recommended project has a 6,620-foot-long, 24-inch-diameter buried penstock, developing total gross head of 222 feet and net head at full flow of 201 feet. The recommended design flow is 17 cfs for an installed generating capacity of 195 kW. Final generating capacity is expected to be 150 to 200 kW once final permit conditions are known and final design is completed. Utility demand and supply with the recommended project, based on 182,200 kWh annual utility demand, is presented in Figure 3 and Table 5. Generally, the diesel plant only needs to operate during late winter, when flow in Knutson Creek is insufficient to supply both the assumed ISFR of 6.6 cfs and the hydro plant. Figure 3: ECUC Demand and Supply with Recommended Hydro Project Knutson Creek Hydroelectric Project Project Size Reevaluation Letter Report to PBVC Polarconsult Alaska, Inc. June 30, 2016 Page 12 of 12 Table 5: Summary of Performance for Recommended Project (Existing Utility Load) PROJECT FEATURES VALUE ENERGY PERFORMANCE OF RECOMMENDED PROJECT Total Annual PBVC Prime Load Supplied by Diesel Plant 3,000 kWh (1.6%) Total Annual PBVC Prime Load Supplied by Hydro Plant 179,200 kWh (98.4%) Total Annual PBVC Prime Load (at generation) 182,200 kWh Total Hydro Energy Dispatched to Supply PBVC Prime Load 179,200 kWh (11.8%) Total Gross Excess Energy Dispatched to Interruptible Electric Heating Services 707,600 kWh (46.7%) Remaining Excess Hydro Energy 628,200 kWh (41.5%) Total Annual Hydro Generation 1,514,900 kWh ECONOMIC EVALUATION OF RECOMMENDED PROJECT Annual Reduction in Utility Fuel Purchases due to Hydro Project 17,100 gallons Annual Reduction in Heating Fuel Purchases due to Interruptible Electric Heating Services 14,400 gallons kWh kilowatt-hours 5.0 REFERENCES AEA, 2016. Alaska Energy Authority. May 2016. Export of monthly data for Pedro Bay Village Council Electric Utility from Power Cost Equalization Program database. FERC, 2015. September 9, 2015. Federal Energy Regulatory Commission. Order Ruling on Declaration of Intention and Finding License Not Required. Docket DI14-6-000. PBVC, 2016. May 2016. Pedro Bay Village Council. Power Cost Equalization Program Electric Utility Monthly Report for May 2016. Polarconsult, 2009. October 2009. Polarconsult Alaska, Inc. Hydroelectric Reconnaissance Study. Knutson Creek Drainage, Town Creek, and Dumbbell Lake. Pedro Bay, Alaska. Final Report. Polarconsult, 2013. November 2013. Polarconsult Alaska, Inc. Knutson Creek Hydroelectric Feasibility Study. Final Report.