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JACK RIVER
HYDROELECTRIC RECONNAISSANCE STUDY
FINAL REPORT
MARCH 2013
Prepared For
NATIVE VILLAGE OF CANTWELL
PO BOX 94
CANTWELL, ALASKA 99729
Prepared by
polarconsult alaska, inc.
1503 WEST 33RD AVENUE, SUITE 310
ANCHORAGE, ALASKA 99503
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report i
EXECUTIVE SUMMARY
In July 2011, the Alaska Energy Authority (AEA) awarded the Native Village of Cantwell (NVC)
grant funds for a hydropower reconnaissance study of Jack River. The funds were awarded
under the state’s Renewable Energy Grant Program, which is administered by the AEA. In
October 2011, the NVC hired Polarconsult Alaska, Inc. (Polarconsult) to conduct a hydroelectric
reconnaissance study of Jack River. This report presents the findings and recommendations of
the hydroelectric reconnaissance study completed for the NVC.
The reach of Jack River considered in this study for hydroelectric development is river mile (RM)
10 to RM 20, which drains an approximately 145‐square mile subbasin in the northern
Talkeetna Mountains. Analysis of 2011‐12 stream gauging data at Jack River collected for this
study indicates the average annual flow in the study reach of Jack River is approximately 150
cubic feet per second (cfs), with minimum annual flow in early May of approximately 30 cfs.
Summer flows
typically range from
300 to 600 cfs, and
flood events exceed
1,000 cfs.
There are three
potential dam sites
along the study
reach of Jack River.
Reconnaissance‐
level investigations
indicate that
technically viable
hydroelectric project
configurations are
possible at all three
dam sites, ranging in
installed capacity
from approximately
1.7 to 7.3
megawatts (MW).
All project
configurations considered for Jack River are storage projects. The 1.4 MW project would only
have sufficient storage capacity to supply Cantwell and surrounding areas during a week‐long
intertie outage, whereas the 7.3 MW project would have sufficient storage capacity to fully
regulate Jack River flow on an annual basis.
Estimated technical and economic attributes of selected project configurations at Jack River are
listed in Table ES‐1.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report ii
Table ES‐1: Summary of Selected Jack River Hydro Project Configurations
PROJECT CONFIGURATIONS DAM SITE #1
(RM 15.13)
DAM SITE #2
(RM 12.42)
DAM SITE #3
(RM 11.69)
ESTIMATED PROJECT
PARAMETERS
A: Maximum Dam
Height,
Powerhouse
Downstream
C: Shorter Dam,
Powerhouse
Downstream
A: Maximum
Dam Height,
Powerhouse
Downstream
C: Shorter Dam,
Powerhouse
Downstream
Design Flow (cfs) 250 cfs 250 cfs 250 cfs 250 cfs
Dam Height (feet) 250 feet 150 feet 135 feet 40 feet
Active Band of Reservoir 2,600 to 2,675 ft.2,500 to 2,575 ft.2,360 to 2,425 ft. 2,270 to 2,300 ft.
Initial Active Reservoir Volume
Final Active Reservoir Volume 1
50,700 acre‐feet
30,500 acre‐feet
12,200 acre‐feet
10,100 acre‐feet
25,500 acre‐feet
12,900 acre‐feet
2,100 acre‐feet
1,200 acre‐feet
Gross Head (feet) 475 feet 185 feet 230 feet 110 feet
Penstock Length (feet)
and Diameter (inches)
16,000 feet /
2 x 60”
2,400 feet /
1 x 60”
11,000 feet /
2 x 60”
6,700 feet /
2 x 60”
Net Head at Full Flow (feet) 452 feet 172 feet 214 feet 100 feet
Installed Capacity (kW) 7.3 MW 3.0 MW 3.6 MW 1.7 MW
Avg. Ann. Net Energy Output
(MWh) 37,300 MWh 12,800 MWh 17,400 MWh 7,500 MWh
Plant Capacity Factor 58%49%55% 51%
ESTIMATED TOTAL INSTALLED
COST RANGE (2012 $,
MILLIONS)
$147.0 ‐ $235.7 $31.5 ‐ $50.3 $69.5 ‐ $111.9 $26.6 ‐ $42.5
ESTIMATED RANGE OF FINANCIAL PARAMETERS (2012 $, MILLIONS)
Financed Capital Cost $139.0 ‐ $235.7 $23.5 ‐ $50.3 $61.5 ‐ $111.9 $18.6 ‐ $42.5
Annual Debt Servicing $5.4 ‐ $17.1 $0.9 ‐ $3.7 $2.4 ‐ $8.1 $0.7 ‐ $3.1
Annual OMR & R $0.6 ‐ $0.9 $0.2 ‐ $0.3 $0.3 ‐ $0.4 $0.1 ‐ $0.2
Operating Margins $0.6 ‐ $1.8 $0.1 ‐ $0.4 $0.3 ‐ $0.9 $0.1 ‐ $0.3
Total Annual Revenue
Requirement $6.6 ‐ $19.8 $1.2 ‐ $4.4 $3.0 ‐ $9.4 $0.9 ‐ $3.6
Estimated Range of Sales Rate
for Energy
($ per kWh)
$0.18 ‐ $0.53 $0.095 ‐ $0.34 $0.17 ‐ $0.54 $0.12 ‐ $0.48
Estimated Range of
Benefit‐Cost Ratio 0.50 – 1.88 0.78 – 3.00 0.49 – 1.85 0.56 – 2.06
1. Final active reservoir volume reflects the estimated available volume once the reservoir has reached
equilibrium sedimentation. Estimates are developed in Appendix D, Section D.3.
The most accessible market for the electric output of a hydro project at Jack River is wholesale
purchase of the full electrical output of the project by Golden Valley Electric Association, Inc.
(GVEA), the local electric utility. Under existing market conditions and estimated site
conditions, the project configurations considered in this study are not economic with wholesale
purchase at GVEA’s current system average avoided energy cost. Under more favorable
financing, site, and/or market conditions, several of the project configurations evaluated in this
study appear to be economically viable with wholesale purchase of the electricity by GVEA.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report iii
Project configurations that may warrant further study have estimated benefit‐cost ratios of
between 0.50 and 3.00. This wide range incorporates a +/‐ 30% range on total installed cost, as
well as a range of operating costs and financing terms.
Initial analysis of environmental impacts associated with the project configurations considered
indicates they would affect resident fish that are likely present in Jack River by impeding fish
passage through the project reach and by changing water quantity and quality downstream of
the project. Alaska’s Fishway Act (AS 16.05.841 to 851) would require that a project at Jack
River either provide for fish passage, provide for hatchery operations to replace the value of
the impacted fisheries, or provide a lump‐sum cash payment as mitigation for fish passage
impacts. In practice, ADF&G prefers to maintain existing habitat, and only rarely accepts
hatchery funding or cash payments in‐lieu of on‐site mitigation.
The project configurations considered in this study are not expected to significantly impact
anadromous fish habitat downstream of the project.
Reservoirs under some project configurations would inundate up to several hundred acres of
wetland and upland habitat for game along Jack River.
Based on the findings of this study, further investigation of hydroelectric development on Jack
River should focus on the following information in order to determine if a hydroelectric project
at Jack River is feasible:
● Collect additional hydrology data to better characterize resource hydrology.
● Market analysis to determine a preferred project configuration.
● Perform geotechnical investigations to assess technical suitability of dam sites and
define design parameters for dams.
● Conduct baseline fisheries survey to determine what resident species are present in the
study reach of Jack River, and the preferred fish passage or impact mitigation strategy.
● Hold scoping meetings with regulatory agencies to outline the scope of environmental
studies, define likely mitigation requirements for aquatic, wetland, and upland impacts,
and determine likely operational constraints on the project.
● Generate refined estimates of electrical output and project costs to determine
economic feasibility.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report iv
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Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report v
REPORT PURPOSE AND LIMITATIONS
Purpose of this Report
A reconnaissance study is the first stage of screening for a potential hydroelectric project, and
represents a limited‐effort, comprehensive review of relevant factors that pertain to the
technical, economic, environmental, and political viability of developing a hydroelectric project
at a given site or for a given power need. Depending on the available budget and the quality of
existing information, the reconnaissance study may include some field data collection for key
information, or may be limited solely to ‘desk‐top’ review of existing information.
This reconnaissance study provides the Native Village of Cantwell (NVC) an initial assessment of
the overall viability of a hydroelectric project at Jack River, and provides information on the
advantages and disadvantages associated with various project sites and configurations. This
information is intended for use by NVC to decide whether to continue with investigation of a
project, and to decide which project site(s) and configuration(s) warrant further investigation.
Limitations
In conducting our analysis and forming the opinions and recommendations summarized in this
report, Polarconsult has relied on information provided by others, and has assumed this
information is complete and correct. Also, Polarconsult has made certain assumptions with
regard to future events, conditions, and circumstances. Polarconsult does not guarantee the
accuracy of the information, data, or opinions contained herein. The methodologies employed
to perform the analysis and arrive at the conclusions in this report follow generally accepted
industry practice for this level of study. We believe that the assumptions and methodologies
used are reasonable and appropriate for meeting the objectives of this study. Future events
and information may result in outcomes materially different from those projected in this study.
Such events and information include, but are not limited to, future energy demand, supply, and
cost along the railbelt; actual site conditions such as ownership, topography, hydrology, and
geology; future trends in local construction, material, and labor costs; and national, state, or
local policies that may affect aspects of the project.
The contents and findings of this report are limited to potential development of a hydroelectric
project at Jack River by NVC, and are suitable only for this intended purpose. Any use of this
report and the information contained therein constitutes agreement that (1) Polarconsult
makes no warranty, express or implied, relating to this report and its contents, (2) the user
accepts sole risk of any such use, and (3) the user waives any claim for damages of any kind
against Polarconsult. The benefit of such waivers, releases, and limitations of liability extend to
Polarconsult, its subcontractors, owners, employees, and agents.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report vi
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Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report vii
TABLE OF CONTENTS
ACRONYMS AND TERMINOLOGY.......................................................................................................................VI
1.0 INTRODUCTION.................................................................................................................................... 1
1.1 PROJECT AUTHORIZATION..........................................................................................................................1
1.2 SUMMARY OF FINDINGS.............................................................................................................................1
1.3 PROJECT EVALUATION PROCESS.................................................................................................................2
1.4 CURRENT AND PREVIOUS STUDIES.............................................................................................................3
2.0 COMMUNITY PROFILE........................................................................................................................... 5
2.1 COMMUNITY OVERVIEW............................................................................................................................5
2.2 EXISTING ENERGY SYSTEM..........................................................................................................................5
3.0 HYDROPOWER DEVELOPMENT OPTIONS .............................................................................................11
3.1 RESOURCE DESCRIPTION..........................................................................................................................11
3.2 OVERVIEW OF PROJECT CONFIGURATIONS CONSIDERED........................................................................15
3.3 RECOMMENDED PROJECT CONFIGURATIONS..........................................................................................16
3.4 ESTIMATED ENERGY GENERATION...........................................................................................................18
3.5 DESCRIPTION OF PROJECT FEATURES.......................................................................................................19
4.0 MARKET ANALYSIS AND OPPORTUNITIES.............................................................................................22
4.1 POTENTIAL BUSINESS MODELS.................................................................................................................22
4.2 POTENTIAL MARKETS................................................................................................................................26
5.0 CONCLUSIONS AND RECOMMENDATIONS ...........................................................................................30
5.1 DEVELOPMENT PLAN AND SCHEDULE......................................................................................................31
6.0 REFERENCES ........................................................................................................................................32
APPENDICES
APPENDIX A – MAPS
APPENDIX B – PHOTOGRAPHS
APPENDIX C – HYDROLOGY DATA
C.1 Methodology
C.2 Gauging Station Information
C.3 Comparable Basins
C.4 Jack River Hydrology Model
APPENDIX D – RESOURCE DATA AND ANALYSIS
D.1 Land Status in Project Area
D.2 Maximum Probable Flood
D.3 Estimated Reservoir Life and Sedimentation
D.4 Outage Rates in Cantwell
APPENDIX E – ENVIRONMENTAL CONSIDERATIONS
APPENDIX F – PERMITTING INFORMATION
APPENDIX G – ECONOMIC ANALYSIS ASSUMPTIONS
APPENDIX H – TABULAR HYDROLOGY DATA
APPENDIX I – DRAFT REPORT REVIEW COMMENTS AND RESPONSES
APPENDIX J – DRAFT REPORT REVIEW COMMENTS AND RESPONSES
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report viii
LIST OF FIGURES
Figure 2‐1: Recent Monthly Peak and Average Power Generation............................................... 9
Figure 3‐1: Estimated Typical Energy Generation for Configurations 1A and 3C........................18
Figure 5‐1: Project Development Schedule.................................................................................31
Figure A‐1: Project Overview and Location Map........................................................................A ‐1
Figure A‐2: General Land Ownership in Project Vicinity.............................................................A‐2
Figure A‐3: Map of Hydrology Basins and Sub‐Basins................................................................A‐3
Figure A‐4: Hydro Project Configuration 1A at Dam Site 1.........................................................A‐4
Figure A‐5: Hydro Project Configuration 2A at Dam Site 2.........................................................A‐5
Figure A‐6: Hydro Project Configuration 3A at Dam Site 3.........................................................A‐6
Photograph B‐1: Stream Gauging Station Installation, November 2011....................................B‐1
Photograph B‐2: Bank Erosion at Stream Gauging Station, May 2012.......................................B‐1
Photograph B‐3: View Downstream Towards Cantwell from Gauging Station..........................B‐2
Photograph B‐4: View Upstream Towards Dam Site 3 from Vicinity of Gauging Station ..........B‐2
Photograph B‐5: View of Jack River Canyon Near Dam Site 1....................................................B‐3
Photograph B‐6: Panoramic View of Jack River Canyon From Wolf Point, Looking SW ............B‐4
Photograph B‐7: Panoramic View of Jack River at Stream Gauging Site, Looking Upriver ........B‐4
Photograph B‐8: Panoramic View of Dam Site 2, Looking Southwest........................................B‐5
Photograph B‐9: Panoramic View of Dam Site 1, Looking Northwest........................................B‐5
Figure C‐1: Winter Flow Measurements at Jack River and Susitna River...................................C‐6
Figure C‐2: Jack River Hydrology Model .....................................................................................C ‐7
Figure C‐3: Flow Duration Curve for Jack River ...........................................................................C ‐8
Figure C‐4: Stage‐Discharge Data for Jack River Gauging Station ..............................................C‐8
Figure C‐5: 2011 – 2012 Jack River Stage Data...........................................................................C ‐9
Figure C‐6: 2011 – 2012 Jack River Gauging Station Air and Water Temperature Data............C‐9
Figure D‐1: Estimated Ultimate Reservoir Sedimentation Profile..............................................D‐5
LIST OF TABLES
Table ES‐1: Summary of Selected Jack River Hydro Project Configurations...................................ii
Table 2‐1: GVEA’s Major Energy Sources for Electricity Generation............................................. 7
Table 2‐2: Recent Electric System Statistics................................................................................... 8
Table 2‐3: Historic Population Data............................................................................................... 8
Table 3‐1: Estimated Attributes of Jack River Dam Sites.............................................................14
Table 3‐2: Range of Project Configurations Considered in this Study.........................................15
Table 3‐3: Cost Estimates and Financial Analysis for Jack River Project Configurations.............17
Table 4‐1: Proposed Alternative Energy Supplies for GVEA........................................................27
Table 4‐2: Selected Railbelt Grid Wheeling Costs........................................................................28
Table C‐1: Jack River Flow Measurements .................................................................................C ‐3
Table C‐2: Summary of Jack River Hydrology Data.....................................................................C ‐5
Table D‐1: Maximum Probable Floods at Jack River Hydro Project Site ....................................D‐2
Table D‐2: Estimated Reservoir Sedimentation Rates and Useful Reservoir Life.......................D‐4
Table D‐3: Estimated Impact of Reservoir Sedimentation on Annual Energy Output ...............D‐6
Table D‐4: 2012 Cantwell Outage Data and Recent GVEA Outage Data....................................D‐7
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report vi
ACRONYMS AND TERMINOLOGY
F degrees Fahrenheit
ac‐ft acre‐foot, acre‐feet. A measure of water volume equal to one acre covered in
water to a depth of one foot.
ADCCED Alaska Department of Commerce, Community, and Economic Development
ADEC Alaska Department of Environmental Conservation
ADF&G Alaska Department of Fish and Game
ADNR Alaska Department of Natural Resources
AEA Alaska Energy Authority
AEP Alaska Environmental Power, LLC
AGS above ground surface
AIS Alaska Intertie System
ANCSA Alaska Native Claims Settlement Act
APA Alaska Power Authority (predecessor to the AEA)
ATV all‐terrain vehicle
Aurora Aurora Energy, LLC
AS Alaska Statute
BGS below ground surface
BHC Brailey Hydrological Consultants
BLM Bureau of Land Management
btu British thermal unit
C.E. Civil Engineer
CEA Chugach Electric Association, Inc.
cfs cubic feet per second
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report vii
DCRA Division of Community and Regional Affairs (organized under ADCCED)
CPCN Certificate of Public Convenience and Necessity
discharge A synonym for stream flow. Flow and discharge are used interchangeably in this
report.
EA environmental attributes. The term “environmental attributes” is used by the
utility industry to describe the desirable aspects of electricity that are generated
from environmentally benign and/or renewable sources. Environmental
attributes are tracked, marketed, bought, and sold separately from the physical
energy. Separating the environmental attributes from the physical energy allows
customers or ratepayers to elect to buy sustainable or “green” energy even if it is
physically unavailable from their electric utility.
FERC Federal Energy Regulatory Commission
FIW Fire Island Wind, LLC
ft foot, feet
FY fiscal year
gal gallon(s)
GVEA Golden Valley Electric Association, Inc.
HDPE high‐density polyethylene
in. inch, inches
IPP independent power producer
ISER Institute of Social and Economic Research (University of Alaska Anchorage)
ISFR in‐stream flow reservation. A minimum amount of flow that must be left in a
river or stream during all or certain times of the year.
kV kilovolt, or 1,000 volts
kVA kilovolt‐ampere
kW kilowatt, or 1,000 watts. One kW is the power consumed by ten 100‐watt
incandescent light bulbs.
kWh kilowatt‐hour. The quantity of energy equal to one kilowatt (kW) expended for
one hour.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report viii
LIDAR Light Detection and Ranging
LLC limited liability company
MEA Matanuska Electric Association, Inc.
MHW mean high water
mi mile, miles
ML&P Municipal Light and Power
MP mile post
MW megawatt
MVA megavolt‐ampere
MWh megawatt‐hour
NAD North American Datum
O&M operations and maintenance
OMR&R operating, maintenance, repair, and replacement
PCE Power Cost Equalization (program)
P.E. Professional Engineer
Polarconsult Polarconsult Alaska, Inc.
prime power, energy, electricity, load, demand
A use of electricity that utility customers expect to be supplied at their
convenience, as in turning on a light or television. The utility is responsible for
taking all reasonable measures to supply sufficient energy into the utility grid to
meet all instantaneous prime demand of its customers. Prime electricity can be
contrasted with excess or interruptible electricity, which is generated by the
utility only when conditions are favorable, and can be interrupted by the utility
without notice.
PTT pressure and temperature transducer
PVC polyvinyl chloride
PZF point of zero flow
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report ix
RCA Regulatory Commission of Alaska
RCC roller‐compacted concrete
RM river mile
rpm revolutions per minute
SDR standard dimension ratio
SFH South Fork Hydro, LLC
SNAP Sustainable Natural Alternative Power
sq.mi. Square mile
USACE U.S. Army Corps of Engineers
USGS U.S. Geological Survey
V volt
WSR wild and scenic river
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 1
1.0 INTRODUCTION
1.1 PROJECT AUTHORIZATION
In July 2011, the Alaska Energy Authority (AEA) awarded the Native Village of Cantwell (NVC)
grant funds for a hydropower reconnaissance study of Jack River. The funds were awarded
under the state’s Renewable Energy Grant Program, which is administered by the AEA.
In October 2011, the NVC hired Polarconsult Alaska, Inc. (Polarconsult) to conduct a
hydroelectric reconnaissance study of Jack River. This report presents the findings and
recommendations of the hydroelectric reconnaissance study completed for the NVC.
1.2 SUMMARY OF FINDINGS
Reconnaissance‐level investigations of Jack River conclude that several hydroelectric project
configurations appear to be technically viable at Jack River, ranging in installed capacity from
approximately 1.7 to 7.3 megawatts (MW). All project configurations considered for Jack River
are storage projects. The 1.7 MW project would only have sufficient storage capacity to supply
Cantwell and surrounding areas during a week‐long intertie outage, whereas the 7.3 MW
project would have sufficient storage capacity to fully regulate Jack River flow on an annual
basis.
The most accessible market for the electric output of a hydro project at Jack River is wholesale
purchase of the full electrical output of the project by Golden Valley Electric Association, Inc.
(GVEA), the local electric utility. Under existing market conditions and estimated site
conditions, the project configurations considered in this study are not economic with wholesale
purchase at GVEA’s current system average avoided energy cost. Under more favorable
financing, site, and/or market conditions, several of the project configurations evaluated in this
study appear to be economically viable with wholesale purchase of the electricity by GVEA.
Project configurations that appear to warrant further study have estimated benefit‐cost ratios
of between 0.50 and 3.00. This range incorporates a +/‐ 30% range on total installed cost, and a
similarly broad range for operating costs and financing terms. Detailed economic assumptions
are presented in Appendix G.
Initial analysis of environmental impacts associated with the project configurations considered
indicates they would affect resident fish that are likely present in Jack River by impeding fish
passage through the project reach and by changing water quantity and quality downstream of
the project. Alaska’s Fishway Act (AS 16.05.841 to 851) would require that a project at Jack
River either provide for fish passage, provide for hatchery operations to replace the value of
the impacted fisheries, or provide a lump‐sum cash payment as mitigation for fish passage
impacts. In practice, ADF&G prefers to maintain existing habitat, and only rarely accepts
hatchery funding or cash payments in‐lieu of on‐site mitigation.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 2
The project configurations are not expected to significantly impact anadromous fish habitat.
The nearest anadromous habitat is more than 50 miles downstream in the Nenana River near
Healy, and the project could reduce flow at the upper limit of anadromous habitat by up to
approximately 7%. Peak project operation in late winter could increase flow at the upper limit
of anadromous habitat by approximately 50% from natural flow conditions. Proper discharge
ramping rates and thermal management of water releases would likely avoid any impacts to
anadromous habitat.
Reservoirs under some project configurations would inundate up to several hundred acres of
wetland and upland habitat for game along Jack River.
Based on the findings of this study, further investigation of hydroelectric developments at Jack
River should focus on the following information in order to determine if a hydroelectric project
at Jack River is feasible:
● Collect additional hydrology data to better characterize resource hydrology.
● Market analysis to determine a preferred project configuration.
● Perform geotechnical investigations to assess technical suitability of dam sites and
define design parameters for dams.
● Conduct baseline fisheries survey to determine what resident species are present in the
study reach of Jack River.
● Hold scoping meetings with regulatory agencies to outline the scope of environmental
studies, define likely mitigation requirements for aquatic, wetland, and upland impacts,
and determine likely operational constraints on the project.
● Generate refined estimates of electrical output and project costs to determine
economic feasibility.
1.3 PROJECT EVALUATION PROCESS
Several hydroelectric development configurations at Jack River were evaluated to define the
range of expected project output and development cost. Relevant resource data for Jack River
were collected and analyzed to develop the project configurations. The resource data included
stream hydrology, site topography, and related information. Environmental and regulatory
factors were also considered in developing candidate project configurations. Economic
evaluations focused on wholesale purchase of the project’s net electrical output by GVEA.
The estimated electrical output for each project configuration was integrated with economic
data comprised of fuel costs, construction costs, operating and maintenance (O&M) costs, and
financing options to develop an estimated benefit‐cost ratio. Under the full range of costs and
financing terms considered in this study, project configurations have an estimated benefit cost
ratio of 0.23 to 3.00, and configurations that appear to warrant closer investigation have
estimated benefit‐cost ratios of 0.50 to 3.00.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 3
1.4 CURRENT AND PREVIOUS STUDIES
1.4.1 Previous Studies
Review of available records indicates that Jack River was identified as a hydropower resource in
two statewide hydropower inventory studies prepared in the late 1970s: 1
1) The Alaska Regional Energy Resources Planning Project, Phase I, Volume II lists a 7
MW project at Jack River. 2
2) The Alaska Regional Energy Resources Planning Project, Phase II, Volume II lists a 13
MW project at Jack River. 3
Both studies were compilations of various prior resource inventories, and neither provided any
information regarding proposed hydroelectric developments at Jack River beyond the proposed
capacity. Given the lack of detail in these inventory studies, their reference sources were not
investigated as part of the current study.
1.4.2 Current Reconnaissance Study
Polarconsult conducted the following field investigations to collect site‐specific information
about Jack River for this reconnaissance study:
● Installed a stream gauge in Jack River and conducted a series of flow measurements to
characterize the hydrology of the river and basin. Field data was analyzed in
conjunction with existing hydrology data for other regional rivers and streams to
generate an initial estimate of Jack River’s hydrological characteristics.
● Performed topographic surveys to characterize two prospective dam sites in the lower
Jack River canyon and a nearby saddle that constrains maximum reservoir elevations for
these dam sites. These topographic surveys were supplemented with new topographic
data collected under the Statewide Digital Mapping Initiative Project in 2011.4
● Performed additional reconnaissance surveys of a third dam site in the Jack River
canyon for initial development concepts at this site.
1 Records reviewed include the AEA energy database and library, the Alaska Resource Library and Information
Service and University of Alaska Anchorage / Alaska Pacific University Consortium Library collections, the
Anchorage Municipal Library collections, and Polarconsult’s archives.
2 Alaska Regional Energy Resources Planning Project, Phase I, Volume II: Inventory of Oil, Gas, Coal,
Hydroelectric, and Uranium Resources, Final Report. State of Alaska, Department of Commerce and Economic
Development, Division of Energy and Power Development. October 1977.
3 Alaska Regional Energy Resources Planning Project, Phase II: Coal, Hydroelectric, and Energy Alternatives
Volume II: Hydroelectric Development. State of Alaska, Department of Commerce and Economic
Development, Division of Energy and Power Development. 1980.
4 Infrared Synthetic Aperture Radar (IFSAR) topographic data collected for the Statewide Digital Mapping
Initiative project in 2011.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 4
Three field visits were completed in support of the above‐listed activities.
● November 2‐3, 2011: Stream gauging station installation and initial stream flow
measurements.
● March 27, 2012: Additional flow measurements and gauging station maintenance.
● July 22‐24, 2012: Additional flow measurements, field reconnaissance, and topographic
surveys.
Field data collected from these trips have been used to complete a reconnaissance study of
Jack River using the methodology described in Section 1.3. This report summarizes the findings
and recommendations of the reconnaissance study.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 5
2.0 COMMUNITY PROFILE
2.1 COMMUNITY OVERVIEW
The community of Cantwell is located at the junction of the Parks Highway and the Denali
Highway, mile post (MP) 209.5 of the Parks Highway. It is located in Broad Pass in the Alaska
Range, at an elevation of approximately 2,100 feet. The community is located approximately
150 air‐miles north‐northeast of Anchorage and 110 air‐miles south‐southwest of Fairbanks at
approximately 63.39° north latitude and 148.95° west longitude (Township 17 South, Range 7
West, Fairbanks Meridian and within U.S. Geological Survey [USGS] quadrangle map Healy B‐4).
Nearby communities are located along the Parks Highway, and include Carlo Creek,
approximately 14 miles to the north, McKinley Village, approximately 21 miles to the north,
Healy, approximately 39 miles to the north, and Trapper Creek, approximately 95 miles to the
south. The Denali National Park entrance and associated developments are approximately 28
miles north of Cantwell along the Parks Highway.
Cantwell has a continental climate with relatively warm summers and long cold winters. Normal
summer temperatures are in the 50s to 70s °F, and normal winter temperatures range from 20
°F below to 10 °F above. The highest recorded temperature is 89 °F, and the lowest recorded
temperature is minus 54 °F. Total precipitation averages 15 inches a year, with an average
snowfall of 78 inches.
Cantwell is not an incorporated city. The NVC is a federally recognized Native village. The
community is located in the Nenana Recording District, the Denali Borough, and the Denali
Borough School District.5
2.2 EXISTING ENERGY SYSTEM
2.2.1 Community Energy Overview
Cantwell is connected to the communities of Carlo Creek and McKinley Village by a three phase
distribution line. Electric service in these communities is provided by GVEA. Electricity is
provided via the Cantwell Substation on the AEA‐owned Alaska Intertie System (AIS) between
the Cook Inlet area and Healy.
2.2.2 Electric Utility Organization
GVEA was incorporated in 1946 under the U.S. Department of Agriculture’s Rural Electrification
Administration (Now Rural Utility Service) regulations. GVEA is a certificated electric utility,
holding Certificate of Convenience and Public Necessity No. 13, originally issued by the Alaska
Public Utilities Commission (predecessor to the Regulatory Commission of Alaska (RCA)) in
1964.
5 This community overview is compiled from data on the Alaska Department of Community and Economic
Development (ADCED) website.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 6
Cantwell, Carlo Creek, and McKinley Village are all located within GVEA’s certificated service
area (Figure A‐2). These communities are not eligible to participate in the state’s Power Cost
Equalization Program (PCE Program).
2.2.3 Generation System
The community of Cantwell and surrounding areas rely on the Cantwell Substation of the AIS
for 100% of their electricity. The Native Village of Cantwell has two 2.4 kilowatt (kW) Skystream
3.7 wind turbines installed near the tribal building. These turbines feed energy into the electric
grid under GVEA’s Sustainable Natural Alternative Power (SNAP) program. There is no other
local utility generation infrastructure. When the AIS experiences an outage, Cantwell and
surrounding areas are blacked out until intertie operation is restored. Past blackouts have been
caused by avalanches, lightning strikes, and similar events. Reversal of power flow on the AIS
also requires a brief outage in Cantwell. Some private businesses and homeowners maintain
backup generators, but these are not configured or suitable to energize the local distribution
system. Outage frequency in Cantwell is four to eight times higher than for GVEA customers
at‐large. Outage frequency in Cantwell is discussed in Appendix D, Section D.4.
GVEA generates electricity from a diverse portfolio of energy sources. Major energy supplies
include coal, fuel oil/naptha, natural gas and hydro. GVEA is currently finishing construction of
an approximately 25 MW wind farm at Eva Creek near Healy that will introduce wind as a
significant energy source for the utility. GVEA expects Eva Creek to supply approximately
76,700 megawatt‐hours (MWh) annually, placing it on par with the Bradley Lake Hydro Project
as an energy source for the utility.6 Table 2‐1 summarizes GVEA’s annual major energy supplies
and costs.
6 Data from GVEA website August 1, 2012: http://www.gvea.com/energy/evacreek
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 7
Table 2‐1: GVEA’s Major Energy Sources for Electricity Generation
Generation Source / Supply Fuel Source Typical Annual Energy
Generation (MWh) (1)
Percent of Total
GVEA Supply
Approximate Price
of Fuel Source (2)
GVEA North Pole Plants,
Zehnder Plant, Delta Plant Diesel/Naptha 507,700 37% $189.18 per MWh
GVEA Healy Plant and Aurora
Energy, LLC Coal 392,900 28% $50.95 per MWh
Wholesale Purchases from
Cook Inlet Utilities Natural Gas 398,800 31% $90.74 per MWh
Bradley Lake Hydro 65,400 4% $57.82 per MWh
Small Member‐Owned (3) Wind/Solar Not available < 1% Not available
1,364,800 100% $105.53 per MWh
(1) Typical annual MWh data is compiled from GVEA quarterly tariff revisions TA231‐13, TA230‐13, TA224‐13, TA222‐13 filed
with the Regulatory Commission of Alaska and covering projected generation data for the period September 2011 through
August 2012.
(2) Price data consolidated from TA220‐13, covering projected costs for the 4th quarter of 2011. Price per kWh obtained by
dividing by 1,000, so $105.53 per MWh is equal to 10.553 cents per kWh.
(3) Small member‐owned generation includes several kW‐scale wind and solar installations, including the two wind turbines in
Cantwell, that participate in GVEA’s Sustainable Natural Alternative Power (SNAP) program, as well as the 1,000 kW Delta
Wind Project which sells energy to GVEA under GVEA’s Experimental Renewable Resource Purchase (ERRP) program.
2.2.4 Electrical Distribution System
The distribution system in Cantwell consists of a 5 megavolt‐ampere (MVA) step‐down
transformer at the AIS Cantwell Substation and a three phase 7.2/12.47 kilovolt (kV)
distribution system. Three phase distribution extends along the Denali Highway for
approximately 1.75 miles east and 1.5 miles west of the Parks Highway Junction, and from this
junction north along the Parks Highway corridor for approximately 21 miles to the communities
of Carlo Creek and McKinley Village, ending at the boundary of Denali National Park and the
Nenana River crossing at MP 231.3. Single phase lines extend into local subdivisions and
neighborhoods. All distribution lines are overhead construction.
2.2.5 Planned Upgrades
No upgrades to Cantwell’s electrical infrastructure are planned.
2.2.6 Existing Load Profile
Cantwell’s electrical demand varies seasonally. Total power throughput at the Cantwell
substation, which includes all demand in Cantwell, Carlo Creek, and McKinley Village, is
approximately 450 to 950 kW during the summer months (generally May 15 through
September 15) and 250 to 600 kW during the winter months (generally September 15 through
May 15). This does not include load at the Denali National Park entrance and associated
developments, which are served from Healy. Recent load patterns in Cantwell for 2010‐2012
are shown in Figure 2‐1 and presented in Table 2‐2. 7
7 Load data for Cantwell Substation provided by GVEA.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 8
Table 2‐2: Recent Electric System Statistics
Parameter 2007 (1) 2008 2009 2010 2011 2012 (2)
WINTER SEASON DEMAND (January 1 through May 31 and October 1 through December 31)
Average Demand (kW) 636 467 498 397 363 302
Hourly Peak Demand (kW) (3) ‐ ‐ ‐ 1,073 963 776
Total Season Energy Demand (MWh) 1,044 2,732 2,952 2,293 2,156 1,377
SUMMER SEASON DEMAND (June 1 through September 30)
Average Demand (kW) 703 708 627 618 723 615
Hourly Peak Demand (kW) (3) ‐ ‐ ‐ 871 1,116 1,793
Total Season Energy Demand (MWh) 506 2,072 1,835 1,808 2,116 1,358
ANNUAL DEMAND (January 1 through December 31)
Total Annual Energy Demand (MWh) 1,550 4,804 4,787 4,101 4,272 2,735
Data provided by GVEA.
(1) 2007 data available from September 1st through December 31st.
(2) 2012 data available from January 1st through August 31st.
(3) Peak hourly demand data is available from July 2, 2010 through August 2, 2012.
2.2.6.1 Population
Historic population data for Cantwell is summarized in Table 2‐3. Prior to the completion of the
Parks Highway in 1971, Cantwell was accessible via air, the Alaska Railroad, and the unpaved
Denali Highway. In these years, Cantwell’s population fluctuated between approximately 17
and 85 people. After the completion of the Parks Highway, Cantwell’s population began
increasing, reaching 147 by 1990 and 222 by 2000. Since 2000, population has decreased by
approximately 10% to 202 in 2011.8
Table 2‐3: Historic Population Data
Year Population
1940 17
1950 0
1960 85
1970 62
1980 89
1990 147
2000 222
2010 219
2011 202
Historic population data from ADCED.
8 Population data from Alaska Department of Community and Economic Development (ADCED) website.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 9
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
Jan 2007 Jan 2008 Jan 2009 Jan 2010 Jan 2011 Jan 2012Monthly Average and Peak kW at Cantwell SubstationPeak Hourly kW
Average Monthly kW
Average Monthly kW
Figure 2‐1: Recent Monthly Peak and Average Power Generation
2.2.7 Projected Future Load Profile
Community electrical demand is a function of population, electricity cost, and available income.
Commercial, industrial, and transient loads can also be major factors in total electrical demand.
A hydro project at Jack River can be used to meet local demand during outages on the AIS.
Because Cantwell is connected to the railbelt energy grid, a Jack River project can generate
more energy than Cantwell needs and export the excess to other railbelt markets. These
market opportunities are discussed in greater detail in Section 4.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 10
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Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 11
3.0 HYDROPOWER DEVELOPMENT OPTIONS
3.1 RESOURCE DESCRIPTION
Jack River’s headwaters are in the northern Talkeetna Mountains, draining in a generally
northerly direction towards the northeastern end of Broad Pass. Jack River collects tributaries
draining the northern Talkeetna Mountains, the northerly portion of Broad Pass, and portions
of the southern Alaska Range before discharging into the Nenana River at an elevation of
approximately 2,020 feet. Major tributaries include Cantwell Creek and Windy Creek (see
Figure A‐3).
In total Jack River drains approximately 390 square miles. Its basin is comprised of subalpine
and alpine valleys and mountainous terrain rising to a maximum elevation of 7,258 feet in the
headwaters of Cantwell Creek in the Alaska Range. Glaciers cover less than 1% of the total
drainage basin. Approximately 20% of the total drainage basin is occupied by sub‐alpine and
alpine valleys. These are generally vegetated by taiga meadows and forests. The balance of the
basin is alpine, either barren rock or tundra.
The reach of Jack River under consideration in this study for hydroelectric development is river
mile (RM) 10 to RM 20, which drains an approximately 145‐square mile subbasin in the
northern Talkeetna Mountains. In the downstream reach, from the Nenana River up to RM 10,
Jack River traverses a low‐gradient alluvial bed as an actively meandering river, with little‐to‐no
practical hydroelectric potential. The reach upstream of RM 20 may have hydroelectric
potential, but review of 1:63,360 scale USGS maps indicates similar gradients as the study
reach, and an apparent lack of promising dam sites. Also, the upstream reach is likely too far
from existing markets and transportation and transmission infrastructure for hydroelectric
developments to be economically viable. Viable micro‐hydro sites suitable for off‐grid
applications may exist in minor tributaries, but these are outside the scope of the current study.
The subbasin above the study reach is predominantly alpine, with approximately 10% of the
basin comprised of subalpine valley floors. There are no significant glaciers in the subbasin.
There are several lakes in the alpine headwaters, but their combined surface area is less than
1% of the total subbasin area.
From RM 20 to RM 16, Jack River meanders through an alpine valley at a grade of
approximately 1%.9 This reach would be wholly or partially inundated by reservoirs under some
project configurations considered in this study. From RM 16 to RM 14.4, Jack River traverses a
steeply incised canyon located approximately four miles southeast of the community of
Cantwell, maintaining a grade of 1 to 1.5% through the canyon. This canyon is one of three
9 Grades in the study reach are calculated using twenty‐five foot and smaller contours, and are measured using
the general topography of the riverbed, not the more serpentine active channel meanders. The grade of the
active river channel will be slightly lower than the listed grades. Short cascades and falls that are not shown by
25‐foot contours likely occur in some parts of the Jack River canyon.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 12
potential dam sites (dam site #1) considered in this study. The floor of this canyon is a
combination of alluvial deposits, talus debris, and in a few locations, bedrock.
Below the canyon, Jack River flows towards the west‐northwest for approximately 2.9 miles
(RM 14.4 to RM 11.5) through a steep‐walled valley. The valley walls are steep rock cliffs and
bluffs typically 50 to 200 feet tall. Most of the valley floor is covered in alluvial deposits, with
talus and rubble cones typically present along the sides of the valley. The valley floor is devoid
of bedrock outcrops, and approximately 400 to 1,000 feet wide. There are two narrow points
in this valley that are potential dam sites, both of which are considered in this study (dam site
#2 and #3). At RM 11.5, Jack River leaves this valley and emerges onto a broad alluvial flood
plain that covers much of the floor of Broad Pass. Jack River actively meanders across the floor
of Broad Pass for the remaining 11.5 miles to its mouth on the Nenana River. Jack River’s active
channel and floodplain is generally 200 to 1,000 feet wide. Revegetated relict channels are
apparent in a corridor that is 2,500 to 5,000 feet wide along this 11.5 mile reach of Jack River.
Developments, including the community of Cantwell, Parks Highway, Denali Highway, and
Alaska Railroad, are protected from flood and erosion hazards by several dikes and similar flood
control structures.
Analysis of 2011‐12 stream gauging data at Jack River indicates the average annual flow in Jack
River near dam site #3 (RM 11.4) is approximately 150 cubic feet per second (cfs), with
minimum annual flow in early May of approximately 30 cfs, summer flows typically in the range
of 300 to 600 cfs, and flood events exceeding 1,000 cfs. Annual precipitation in the Jack River
basin is estimated at 30 inches. Hydrology analysis of Jack River is presented in Appendix C.
The three dam sites in the study reach of Jack River are described below. Technical attributes
of the three dam sites are summarized in Table 3‐1, and the dam sites are shown on Figure A‐1.
Dam Site #1, in the Jack River canyon at approximately RM 15.13. This canyon presents a
potential dam site for a dam of up to approximately 250 feet in height, creating a
approximately 865‐acre reservoir at an elevation of approximately 2,675 feet. The canyon
topography could support a taller dam to approximately 400 feet, but a saddle
approximately ½ mile to the east would require a supplemental gravity dam to increase the
reservoir elevation above approximately 2,690 feet.
Dam Site #2, in the river valley at approximately RM 12.42. At this point, the valley narrows to
a width of 430 feet at the floor (elevation 2,290 feet) and 1,050 feet at the valley rim
(elevation 2,470 feet). A significant prominence extends from the northeast valley wall to
the midpoint of the valley and a height of 2,400+ feet. This location presents a potential
dam site for a 135‐foot tall dam, creating an approximately 450‐acre reservoir at an
elevation of 2,425 feet. This reservoir elevation would require an approximately 45‐foot tall
supplemental dam to block a saddle at 2,385‐foot elevation located approximately ¾‐mile
east of the dam site. This supplemental dam would have a 1,500 foot long crest.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 13
Dam Site #3, in the river valley at approximately RM 11.69. At this point, the valley narrows to
a width of 550 feet at the floor (elevation 2,260 feet) and 740 feet at the valley rim
(elevation 2,370 feet). This location presents a potential dam site for a 100‐foot tall dam,
creating an approximately 350‐acre reservoir at an elevation of 2,360 feet. This reservoir
elevation would require an approximately 20‐foot tall by 850 foot long wing wall along the
northeast rim of the valley.
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report 14 Table 3‐1: Estimated Attributes of Jack River Dam Sites ESTIMATED ATTRIBUTES OF JACK RIVER DAM SITES ATTRIBUTE DAM SITE #1 DAM SITE #2 DAM SITE #3 Location along Jack River RM 15.13 RM 12.42 RM 11.69 Conceptual Site Plans Figure A‐4 Figure A‐5 Figure A‐6 Photographs (Appendix B) Photographs B‐5, B‐9 Photograph B‐8 Photographs B‐7, B‐9 Maximum Dam Height 250 feet 135 feet 100 feet DAM SITE FLOOR Floor Elevation 2,425 feet 2,290 feet 2,260 feet Floor Width 150 feet 430 feet 550 feet Floor Composition Combination of alluvial deposits from Jack River and talus / rubble deposits from mass wasting events along canyon walls. Exposed bedrock likely at a few locations. Alluvial deposits to unknown depth. A significant rock outcrop extends into the canyon from the right wall, rising to 2,430 ft. at the dam site. Alluvial deposits to unknown depth. No bedrock is visible at surface. DAM SITE LEFT WALL (SOUTHWESTERLY SIDE OF JACK RIVER) Description Exposed rock faces, very sparsely vegetated at upper elevations. Talus and rubble cones at lower elevations. Exposed rock outcrop. Significantly weathered and decomposed, sparsely vegetated. Decomposing rock face generally at angle of repose, mostly vegetated. Slope 1:1 slope and steeper. 1:1 slope, decomposed. rock face. More gradual at toe except where scoured by river. 1:1.5 uniform slope, with some steeper rock faces. More gradual at toe except where scoured by river. Comments None. None. None. DAM SITE RIGHT WALL (NORTHEASTERLY SIDE OF JACK RIVER) Description Mostly vegetated talus and rubble deposits, some rock outcrops at higher elevations. Decomposed rock at angle of repose, mostly vegetated. Exposed rock outcrop. Significantly weathered and decomposed. Slope 1:1 slope, variable. 2:1 vegetated slope 1:1 to 1:4 sloped rock wall, some vertical faces. Comments None. Bedrock likely within 5 ft. of surface in most areas. None. ESTIMATED MAXIMUM DAM CREST Length 750 feet 950 feet 740 feet Crest Elevation 2,675 feet 2,425 feet 2,380 feet Spillway Structure Over dam crest. Over dam crest. Over dam crest or via ¼‐mile spillway through right bank terrain. Limiting Feature(s) A 2,685 foot elevation saddle 3,400 feet south of RM 16.0. A 2,385 foot elevation saddle above the right bank at RM 13.5 and a second saddle above the right bank at RM 14.5 with elevation 2,435 feet. Rim elevation above right bank for 3,400 feet upstream from dam site and a saddle at 2,385‐foot elevation on the right bank at RM 13.5. Comments Dam crest could be raised by adding a saddle dam. Stated dam height provides sufficient reservoir storage for full annual regulation of Jack River. The maximum crest elevation requires an approximately 45 foot tall by 1,500 foot long saddle dam located approximately 4,300 feet east of main dam. The maximum crest elevation requires an approximately 25 foot tall by 850 foot long wing wall along the right‐side rim of the valley. ESTIMATED MAXIMUM RESERVOIR CHARACTERISTICS Active Band of Reservoir 2,600 to 2,675 feet 2,360 to 2,425 feet 2,325 to 2,360 feet Active Storage Capacity 44,500 acre‐feet 25,500 acre‐feet 9,300 acre‐feet Inactive Storage Capacity 52,000 acre‐feet 7,800 acre‐feet 6,000 acre‐feet Maximum Reservoir Area 865 acres at 2,675 feet 450 acres at 2,425 feet 350 acres at 2,360 feet Upstream Limit of Reservoir RM 20.0 RM 15.0 RM 14.0 Design Flow for Constant Annual Output 150 cfs (full annual regulation of Jack River) 110 cfs 100 cfs RM: river mile. Left and right are looking downstream.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 15
3.2 OVERVIEW OF PROJECT CONFIGURATIONS CONSIDERED
There are three potential dam sites along the study reach of Jack River. At each dam site, up to
three potential project configurations were evaluated:
A. Tall dams that fully develop the reservoir capacities of the three dam sites. These projects
include penstocks and downstream powerhouses to maximize total head on the project.
B. Tall dams that fully develop the reservoir capacities of the three dam sites. Powerhouses
are located at the base of the dam.
C. Shorter dams with penstocks and downstream powerhouses. These projects have
decreased reservoir capacity and less total head, but they also are less costly yet still
provide significant generating capacity and reservoir storage.
These configurations are listed in Table 3‐2. All project configurations have a design flow of 250
cubic feet per second (cfs).
This report refers to different development options at Jack River by the dam site (1 through 3)
and the project configuration (A through C). Thus, configuration “2B” refers to a project with a
maximum height dam at dam site #2 and with the powerhouse located at the base of the dam.
Table 3‐2: Range of Project Configurations Considered in this Study
Project Configuration Dam Site #1
(RM 15.13)
Dam Site #2
(RM 12.42)
Dam Site #3
(RM 11.69)
A. Maximum dam height, powerhouse
downstream Configuration 1A Configuration 2A Configuration 3A
B. Maximum dam height, powerhouse
near base of dam Configuration 1B Configuration 2B Configuration 3B
C. Shorter dam, powerhouse
downstream Configuration 1C
Not Considered
(Substantially
similar to
Configuration 3C)
Configuration 3C
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 16
3.3 RECOMMENDED PROJECT CONFIGURATIONS
The project configurations listed in Table 3‐2 were analyzed for estimated cost, energy
generation, and economics. The results of this analysis are presented in Table 3‐3.
Assumptions used in the analysis are explained in Appendix G. Table 3‐3 does not consider any
operating restrictions that may be imposed on reservoir management or flow releases for
environmental reasons.
The most favorable project configuration at Jack River will be defined by the needs of the
market that the project is built to serve. Because Cantwell is connected to the railbelt energy
grid, it is likely that the most favorable project configuration will be that with the lowest cost of
energy. Other factors that may influence project selection include storage capacity for winter
generation and meeting peak demand, backup generation capability for Cantwell and
surrounding areas, flood control capabilities, and environmental impacts.
Project configurations 1A, 1C, 2A, and 3C each have the potential to provide energy at a lower
cost than GVEA’s existing incremental energy cost, if project capital costs and financing terms
are favorable. Configuration 1A provides the most reservoir storage, generating capacity, and
electrical output, and is capable of fully regulating flow in Jack River throughout the year.
Configurations 1C and 2A provide an intermediate amount of reservoir storage, and are capable
of delivering peak power for sustained periods during the winter months and providing backup
generation in Cantwell during outages. Configuration 3C is essentially a run‐of‐river project,
providing sufficient storage only to provide back up generation for Cantwell and surrounding
areas during an outage. All configurations can generate full power throughout the summer
season.
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report 17 Table 3‐3: Cost Estimates and Financial Analysis for Jack River Project Configurations PROJECT CONFIGURATIONS DAM SITE #1 (RM 15.13) DAM SITE #2 (RM 12.42) DAM SITE #3 (RM 11.69) ESTIMATED PROJECT PARAMETERS A: Maximum Dam Height, Powerhouse Downstream B: Maximum Dam Height, Powerhouse at Dam C: Shorter Dam, Powerhouse Downstream A: Maximum Dam Height, Powerhouse Downstream B: Maximum Dam Height, Powerhouse at Dam A: Maximum Dam Height, Powerhouse Downstream B: Maximum Dam Height, Powerhouse at Dam C: Shorter Dam, Powerhouse Downstream Design Flow (cfs) 250 cfs 250 cfs 250 cfs250 cfs 250 cfs 250 cfs 250 cfs 250 cfs Dam Height (feet) 250 feet 250 feet 150 feet135 feet 135 feet 100 feet 100 feet 40 feet Spillway Elevation (feet) 2,675 feet 2,675 feet 2,575 feet2,425 feet 2,425 feet 2,360 feet 2,360 feet 2,300 feet Tailwater Elevation (feet) 2,225 feet 2,425 feet 2,385 feet2,195 feet 2,290 feet 2,190 feet 2,260 feet 2,190 feet Gross Head (feet) 475 feet 250 feet 185 feet230 feet 135 feet 170 feet 100 feet 110 feet Access Roads and Trails (feet) 28,000 feet 28,000 feet 28,000 feet20,000 feet 20,000 feet 15,000 feet 15,000 feet 15,000 feet Power and Communication Line Extensions (feet) 8,000 feet 16,000 feet 13,000 feet800 feet 11,000 feet 800 feet 7,500 feet 800 feet Penstock Length (feet) and Diameter (inches) 16,000 feet /2 x 60” 300 feet / 2 x 48” 2,400 feet / 1 x 60”11,000 feet / 2 x 60” 500 feet / 1 x 60” 6,700 feet / 2 x 60” 500 feet / 1 x 60” 6,700 feet / 2x60” Net Head at Full Flow (feet) 452 feet 248 feet 172 feet214 feet 132 feet 160 feet 97 feet 100 feet Reservoir Area (Acres) 865 acres 865 acres 330 acres450 acres 450 acres 350 acres 350 acres 115 acres Active Band of Reservoir 2,600 to 2,675 feet 2,600 to 2,675 feet 2,500 to 2,575 feet2,360 to 2,425 feet 2,360 to 2,425 feet 2,325 to 2,360 feet 2,325 to 2,360 feet 2,270 to 2,300 ft. Initial Active Reservoir Volume (acre‐feet) 1 50,700 acre‐feet 50,700 acre‐feet 12,200 acre‐feet25,500 acre‐feet 25,500 acre‐feet 9,300 acre‐feet 9,300 acre‐feet 2,100 acre‐feet Initial Inactive Reservoir Volume (acre‐feet) 1 28,900 acre‐feet 28,900 acre‐feet 3,500 acre‐feet7,800 acre‐feet 7,800 acre‐feet 5,900 acre‐feet 5,900 acre‐feet 200 acre‐feet Installed Capacity (kW) 7.3 MW 4.2 MW 3.0 MW3.6 MW 2.2 MW 2.7 MW 1.6 MW 1.7 MW Avg. Ann. Net Energy Output (MWh) 37,300 MWh 23,400 MWh 12,800 MWh17,400 MWh 9,300 MWh 12,500 MWh 7,100 MWh 7,500 MWh Plant Capacity Factor 58% 64% 49%55% 47% 53% 49% 51% ESTIMATED TOTAL INSTALLED COST RANGE (2012 $, MILLIONS) Pre‐construction (studies, permitting, design, site control, etc.) $2.3 ‐ $3.8 $2.3 ‐ $3.8 $2.3 ‐ $3.8$1.2 ‐ $2.1 $1.2 ‐ $2.0 $0.6 ‐ $1.0 $0.6 ‐ $1.0 $0.4 ‐ $0.7 Power and Communication Lines $0.6 ‐ $0.9 $0.5 ‐ $0.9 $0.6 ‐ $1.0$0.2 ‐ $0.3 $0.4 ‐ $0.7 $0.1 ‐ $0.2 $0.3 ‐ $0.5 $0.1 ‐ $0.1 Access Roads and Flood Protection $1.6 ‐ $2.6 $1.6 ‐ $2.6 $1.4 ‐ $2.3$1.0 ‐ $1.7 $1.0 ‐ $1.7 $0.8 ‐ $1.4 $0.8 ‐ $1.4 $1.0 ‐ $1.6 Dam and Reservoir $70.8 ‐ $117.9 $70.8 ‐ $117.9 $8.6 ‐ $14.3$23.9 ‐ $39.9 $23.9 ‐ $39.9 $32.8 ‐ $54.6 $32.8 ‐ $54.6 $8.1 ‐ $13.5 Saddle Dam $0.0 ‐ $0.0 $0.0 ‐ $0.0 $0.0 ‐ $0.0$3.8 ‐ $6.3 $3.8 ‐ $6.3 $0.0 ‐ $0.0 $0.0 ‐ $0.0 $0.0 ‐ $0.0 Penstock $11.0 ‐ $18.4 $0.3 ‐ $0.5 $1.0 ‐ $1.7$8.2 ‐ $13.7 $0.3 ‐ $0.5 $5.3 ‐ $8.9 $0.3 ‐ $0.5 $5.3 ‐ $8.9 Powerhouse $5.4 ‐ $9.1 $3.5 ‐ $5.8 $3.0 ‐ $5.0$3.3 ‐ $5.5 $2.7 ‐ $4.5 $2.8 ‐ $4.7 $2.5 ‐ $4.1 $2.2 ‐ $3.6 Construction Equipment $7.9 ‐ $13.1 $4.6 ‐ $7.7 $4.8 ‐ $8.0$5.8 ‐ $9.7 $4.6 ‐ $7.7 $4.6 ‐ $7.7 $3.9 ‐ $6.5 $1.0 ‐ $1.7 Construction Engineering and Inspections $4.4 ‐ $7.4 $4.3 ‐ $7.2 $0.6 ‐ $1.0$1.8 ‐ $3.1 $1.8 ‐ $3.0 $2.1 ‐ $3.6 $2.1 ‐ $3.5 $0.7 ‐ $1.1 Construction Management / Administration $4.9 ‐ $8.1 $4.1 ‐ $6.8 $1.0 ‐ $1.6$2.3 ‐ $3.8 $1.8 ‐ $3.1 $2.3 ‐ $3.9 $2.0 ‐ $3.4 $0.9 ‐ $1.5 Contingency $38.1 ‐ $54.4 $32.2 ‐ $46.0 $8.2 ‐ $11.6$18.0 ‐ $25.8 $14.5 ‐ $20.8 $18.0 ‐ $25.8 $15.9 ‐ $22.7 $6.9 ‐ $9.8 ESTIMATED TOTAL INSTALLED COST RANGE (2012 $, MILLIONS) $147.0 ‐ $235.7 $124.2 ‐ $199.2$31.5 ‐ $50.3$69.5 ‐ $111.9$56.0 ‐ $90.2 $69.4 ‐ $111.8 $61.2 ‐ $98.2$26.6 ‐ $42.5ESTIMATED RANGE OF FINANCIAL PARAMETERS 2 Capital Cost Paid by Grants $30,000 ‐ $8M $30,000 ‐ $8M $30,000 ‐ $8M$30,000 ‐ $8M $30,000 ‐ $8M $30,000 ‐ $8M $30,000 ‐ $8M $30,000 ‐ $8M Financed Capital Cost (Million $) $139.0 ‐ $235.7 $116.2 ‐ $199.2 $23.5 ‐ $50.3$61.5 ‐ $111.9 $48.0 ‐ $90.2 $61.4 ‐ $111.8 $53.2 ‐ $98.2 $18.6 ‐ $42.5 Annual Debt Servicing Cost (Million $) $5.4 ‐ $17.1 $4.5 ‐ $14.5 $0.9 ‐ $3.7$2.4 ‐ $8.1 $1.9 ‐ $6.6 $2.4 ‐ $8.1 $2.1 ‐ $7.1 $0.7 ‐ $3.1 Annual OMR & R Costs (Million $) $0.6 ‐ $0.9 $0.4 ‐ $0.6 $0.2 ‐ $0.3$0.3 ‐ $0.4 $0.1 ‐ $0.2 $0.2 ‐ $0.3 $0.1 ‐ $0.2 $0.1 ‐ $0.2 Operating Margins (Million $) $0.6 ‐ $1.8 $0.5 ‐ $1.5 $0.1 ‐ $0.4$0.3 ‐ $0.9 $0.2 ‐ $0.7 $0.3 ‐ $0.8 $0.2 ‐ $0.7 $0.1 ‐ $0.3 Total Annual Revenue Requirement (Million $) $6.6 ‐ $19.8 $5.4 ‐ $16.6 $1.2 ‐ $4.4$3.0 ‐ $9.4 $2.2 ‐ $7.5 $2.9 ‐ $9.2 $2.4 ‐ $8.0 $0.9 ‐ $3.6 Estimated Range of Sales Rate for Energy ($ per kWh) $0.18 ‐ $0.53 $0.23 ‐ $0.71$0.095 ‐ $0.34$0.17 ‐ $0.54$0.23 ‐ $0.80 $0.23 ‐ $0.74 $0.34 ‐ $1.13$0.12 ‐ $0.48Estimated Range of Benefit‐Cost Ratio 0.50 – 1.88 0.37 – 1.390.78 – 3.000.49 – 1.850.33 – 1.23 0.36 – 1.33 0.23 – 0.860.56 – 2.061. See Appendix D, Section D.3 for analysis of reservoir sedimentation rate, estimated reservoir life, and estimated effect on project economics. 2. See Appendix G for economic analysis assumptions.
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March 2013 – Final Report 18
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000OctoberNovemberDecemberJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptember
Daily Power Generation (kW)Configuration 1A (Peak Output)
Configuration 1A (Constant Output)
Configuration 3C
3.4 ESTIMATED ENERGY GENERATION
Figure 3‐1 presents estimated typical annual energy generation for project configurations 1A
and 3C, which represent the largest and smallest project configurations, respectively.
Estimated annual energy generation for all project configurations considered in this study are
listed in Table 3‐3.
Figure 3‐1 shows two annual power curves for Configuration 1A. The bold red line reflects the
power generation if the plant is operated at full capacity continuously until the reservoir is
drawn down. In practice, this peak output can be shifted to any time of day or year when it has
the greatest value. The light red line represents power generation if the plant is operated at a
steady flow year‐round. The slight variation in this line is due to fluctuations in reservoir level,
which affect project head and thus power generation. Configuration 3C lacks this operational
flexibility due to its smaller reservoir volume. In Figure 3‐1, the Configuration 3C reservoir is
drawn down between late September and early November, and then the project operates as a
run‐of‐river project until the reservoir refills in June. In practice, it would be preferable to
reduce generation in September in order to maintain a full reservoir so the project can be used
to provide backup generation for Cantwell through the winter months.
Figure 3‐1: Estimated Typical Energy Generation for Configurations 1A and 3C
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3.5 DESCRIPTION OF PROJECT FEATURES
Key features of project configuration 1A are described in the following sections. As
appropriate, the narratives also apply to other project configurations as well.
3.5.1 Access and Staging
Access to the project would require construction of new roads from the Denali Highway to the
project dam site and powerhouse site. Construction material and equipment would be trucked
into the dam and powerhouse sites over these roads. If possible, a quarry would be sited and
developed near the dam site to provide a local source for aggregate for the dam. Cement, clay,
pipe, and other materials could be brought to Cantwell via the Parks Highway or Alaska Railroad
and then hauled by truck to the project site. One or more staging yards would be required for
the project. Suitable terrain exists in reasonable proximity to the project work sites for staging
yards.
3.5.2 Construction Schedule
Configuration 1A is estimated to take two or three years to construct. The first year of
construction would include constructing access roads, extending power to the dam site, scaling
the canyon walls at the dam site, developing an on‐site quarry, diverting Jack River, and
excavating the canyon floor to rock. The base of the dam would be built, including the
permanent bypass structure to route Jack River through the dam structure.
The second year would include completion of the dam, clearing of the reservoir, installation of
the penstocks, construction of the powerhouse, tailrace, and power lines, installation of the
turbines and generators, and commissioning.
If a third year were required, it would focus on work at the dam site, with most other year 2
work deferred to year 3.
Configuration 3C, and possibly other configurations at dam sites 2 and 3, could be constructed
in a single year.
3.5.3 Transmission Line
The electrical output of the project would be brought to market via a three‐phase overhead
distribution line. For projects under approximately 5 MW, the distribution line would be similar
to the existing 7.2 / 12.47 kV distribution line along the Denali Highway near Cantwell. For
larger projects, a higher voltage line may be required. A larger project may also require
upgrade of the existing 1.9 miles of three phase line along the Denali Highway to a higher
voltage. Also, a larger (or second parallel) step‐up transformer at the Cantwell Substation
would be required to feed project output onto the AIS for transmission to railbelt markets.
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3.5.4 Controls and System Integration
The project would include dedicated communications circuits between the intake at the dam
and the powerhouse to operate the project. A dedicated communications circuit would also be
installed between the powerhouse and the Cantwell Substation to integrate the project with
GVEA’s control systems. These circuits would allow for remote operation, monitoring, and
diagnosis of the project.
The control regime used to manage project operations would depend on the market for the
electricity. If the electricity was sold to GVEA on a wholesale basis, the project could be
configured to be dispatchable by GVEA to minimize GVEA’s fuel and purchased power costs,
thereby maximizing the project’s value. Configuration 1A’s significant storage capacity would
allow GVEA to dispatch the Jack River project in order to reduce use of its highest‐cost peaking
plants.
3.5.5 Dam / Intake
Dam site 1 appears suitable for a roller‐compacted concrete (RCC) gravity dam. The dam is
assumed to be founded on bedrock beneath Jack River, and constructed with a vertical
upstream face and 1:1 slope on the downstream face. The center portion of the downstream
face would serve as the reservoir spillway. The intake structure would be integral to the dam,
or sited on existing terrain on the right bank at the dam site.
Dam sites 2 and 3 appear suitable for impervious core rock fill gravity dams. These dams are
assumed to be founded on bedrock or suitable material beneath Jack River. The upstream face
is assumed to have a 2:1 slope, and the downstream face is assumed to have a 2.5:1 slope. A
concrete spillway would be constructed on the downstream face of the dam.
Detailed geological assessments of the dam sites would be required to determine their
geotechnical suitability for the reservoir impoundments considered in this study and the
technical design criteria for the dams, spillways, and associated project features.
3.5.6 Penstock
Configuration B projects would include penstocks that are integral to the dam structure.
Configuration A and C projects would include buried penstocks to convey water from the intake
structure to the off‐site powerhouse. This study assumed the use of one or two 60‐inch
penstocks depending on penstock length and head losses. Penstock materials could include
high‐density polyethylene (HDPE) or PVC in the lower pressure sections, and steel or ductile
iron in the higher pressure sections.
Reconnaissance‐level analysis of penstock options indicates that the installed cost of multiple
60‐inch penstocks may be lower than the installed cost for a single larger‐diameter penstock.
The cost saving arises principally from the lower cost of shipping 60‐inch pipe to Cantwell. Two
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sections of 60‐inch pipe can be shipped per truck, whereas larger diameter pipe is typically
limited to one section per truck. This approximately doubles the per‐foot shipping cost for the
pipe. Also, providing a separate penstock for each turbine‐generator unit provides greater
operational redundancy and reliability, which may be desirable for the larger project
configurations considered. Penstock design and configuration would be addressed in the
design stage of the selected project configuration.
3.5.7 Powerhouse
For configuration 1A, the powerhouse would be a metal or concrete building sited north of the
Denali Highway. It would house the turbines, generators, controls, and appurtenances. A
series of Francis turbines would likely be used for Configuration 1A, 1B, 1C, and 2A. Project
configurations with net head less than approximately 110 feet (configurations 2B, 3B, and 3C)
could also use a series of Kaplan turbines.
3.5.8 Tailrace
The tailrace for project configuration 1A would discharge to a series of ponds and wetlands
located north of the Denali Highway. These ponds drain to a minor tributary that discharges to
Jack River at approximately RM 9.8 The tailrace would consist of a series of channels and
control structures excavated between these ponds to establish a pathway capable of handling
the project flow without significantly changing the normal water levels in these ponds.
The viability of this tailrace configuration would depend on the specific configuration and
associated impacts on water quality and biology of the affected ponds and wetland areas. If
this configuration were selected for further study, detailed analysis of these matters would
occur during the feasibility, permitting, and design phases of the project.
The tailrace for project configuration 1C would discharge back to Jack River at approximately
RM 14. The tailrace would be an excavated channel extending from the powerhouse to the
active channel of Jack River.
The tailrace for project configurations 2A, 3A, and 3C would discharge back to Jack River at
approximately RM 10.2. The tailrace would be an excavated channel extending from the
powerhouse to the active channel of Jack River.
Tailraces for project configurations 1B, 2B and 3B would be located at the downstream toe of
the dams, discharging into the natural channel of Jack River immediately downstream of the
dam site.
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4.0 MARKET ANALYSIS AND OPPORTUNITIES
The market for electricity from Jack River is first serving the Cantwell / Carlo Creek / McKinley
Village distribution service area, and second exporting electricity to the railbelt over the AIS.
Based on current information and market conditions, the most accessible market for electricity
from a hydro project at Jack River would be wholesale purchase by GVEA at its avoided energy
cost or a negotiated price. Under this business arrangement, NVC would be operating as an
Independent Power Producer (IPP). GVEA is aware of and supportive of this study. Detailed
discussions with GVEA regarding power sales are premature at this stage of study. This and
other potential business models and markets are discussed in this section, as follows:
● Section 4.1 discusses potential business models for a Jack River Hydro Project
● Section 4.2 discusses potential market for electricity from a Jack River Hydro Project.
4.1 POTENTIAL BUSINESS MODELS
There are three business models that NVC could adopt as the owner of a hydro project at Jack
River.
● Independent Power Producer,
● Electric Utility, or
● Non‐Utility Entity with Directed Sales.
4.1.1 Independent Power Producer
NVC could become an Independent Power Producer (IPP). IPPs are non‐utility energy
producers that output commercial quantities of electricity to the electric grid on a wholesale
basis. They are generally distinguished from ‘traditional’ utilities by the fact that they do not
provide retail sales of electricity to end users, and do not own and maintain transmission or
distribution systems beyond what is necessary to deliver their electricity to the local grid.
IPPs are a well‐established market presence in the Lower 48, but their role in Alaska’s (and the
railbelt’s) electric industry is still relatively new and evolving. IPPs have been operating on the
railbelt grid for over 20 years, but until very recently their role has not been fully recognized by
most Alaska utility planning efforts or in the State’s regulatory framework.10 This situation has
started to change in the past few years, with increased recognition of the cost savings, risk
management benefits, and other benefits IPPs provide to electric utilities and their
ratepayers.11
10 One of the earliest private‐sector IPPs on the railbelt grid was Enerdyne, LLC, operator of a 100‐kW run‐of‐river
hydro project near Palmer that has sold wholesale energy to MEA since 1991. Enerdyne is owned by principals
of Polarconsult. Another early IPP is Aurora Energy, LLC, which started selling electricity to GVEA from its coal‐
fired plant in Fairbanks in 1995.
11 There are at least five commercial‐scale IPPs now operating on the railbelt, with several others in pre‐
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Under Alaska’s existing regulations, many IPPs still fall under the definition of a utility, and may
face varying levels of regulatory oversight or exemption by the RCA. Representative examples
of regulatory oversight exercised over IPPs operating on the railbelt include:
● Aurora Energy, LLC (Aurora) Aurora, an affiliate of Usibelli Coal Mine, Inc., operates a coal‐
fired power plant in Fairbanks and sells wholesale power to GVEA. Aurora is an
economically regulated certificated public utility operating under CPCN No. 520.12
● Fire Island Wind, LLC (FIW) FIW, a wholly owned subsidiary of Cook Inlet Region, Inc., is
currently building a 17 MW wind farm on Fire Island that will sell 100% of its output to
Chugach Electric Association, Inc. (CEA) at a fixed net price of $97 per MWh over a 25‐year
term. FIW was exempted from RCA regulation by Alaska Statute (AS) 42.05.711(r), and does
not have a CPCN.13
● South Fork Hydro, LLC (SFH) SFH is a privately‐owned company currently developing a 1.2
MW run‐of‐river hydro project on the south fork of Eagle River near Anchorage. SFH will
sell 100% of its output to Matanuska Electric Association, Inc. (MEA) at a fixed net price of
$70 per MWh over a 30‐year term.14 SFH was granted exemption from RCA regulation
under AS 42.05.711(d), and does not have a CPCN.15
● Alaska Environmental Power, LLC (AEP) AEP is a privately‐owned company that operates a
wind farm with an installed capacity of approximately 1,000 kW in Delta Junction, Alaska.
AEP sells 100% of its output to GVEA for a variable price equal to GVEA’s system average
avoided energy cost reported in its tariff on a quarterly basis. AEP is a Qualified Facility
under Federal regulations, which exempts it from state utility regulation. However, because
of conditions associated with a construction grant received from the AEA, AEP is required to
operate as a certificated public utility under CPCN No. 742.16
4.1.2 Independent Electric Utility
Cantwell and surrounding areas could withdraw from GVEA service territory and form an
independent electric utility. The resulting utility would resemble the City of Seward’s Electric
Department, which is an independent utility serving Seward and the surrounding area. Forming
an independent utility would allow Cantwell to establish its own electric rates independent of
commercial stages of project development. The Railbelt Integrated Resource Plan acknowledged the positive
role IPPs can play in the railbelt energy market (AEA, 2010).
12 See Order No. 2 in RCA Docket U‐97‐139.
13 See Order No. 5 in RCA Docket U‐11‐100. AS 42.05.711(r) is a very narrowly defined exemption criteria that will
not apply to NVC.
14 See AEA / AIDEA Board Resolution 2012‐02. One of the members of SFH is a principal at Polarconsult.
15 See Order No. 2 in RCA Docket U‐08‐102.
16 See Order No. 2 in RCA Docket U‐11‐111.
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GVEA’s rates. This would expose Cantwell to the costs or savings associated with a hydro
project at Jack River.
While this course is an option, it would be an ambitious endeavor for NVC and the community
of Cantwell with significant cost, risk, and responsibility. Even if the cost of energy from Jack
River was lower than the cost of energy from GVEA, the reduced economies of scale for such a
small utility could still result in higher retail electric rates than GVEA.17 Based on available
information and analysis in this study, it is likely that formation of an independent Cantwell
electric utility would result in higher rates for local utility customers.
In order to form a separate utility, Cantwell would need to:
● Demonstrate to the RCA that it is fit, willing, and able to operate as an electric utility
serving Cantwell.
● Purchase the existing distribution infrastructure from GVEA. The cost basis or fair
market value of this infrastructure is unknown, but could easily be in the millions of
dollars. Some of the infrastructure was likely built using government grants or loans.
● Assume responsibility for all electric utility operations, including maintenance and repair
of the distribution system, billing, metering, and customer service, and operation and
maintenance of local generation plants.
● Provide for backup energy generation to supplement the hydro when it is out of service.
This could be achieved with local diesel generators or possibly through power purchase
agreements via the AIS.
● Become a party to the Alaska Intertie Agreement that governs access to and use of the
AIS. This agreement was updated in 2011, and now allows for the entrance of non‐
utility parties, although it is questionable if a stand‐alone Cantwell utility could qualify as
a party to the agreement. 18
● Successfully demonstrate to the RCA that the secession of Cantwell from GVEA is in the
public interest. It is unknown how easy this would be to achieve. There is a general
movement towards increased integration of the railbelt utilities, and forming a separate
Cantwell utility would be counter to this trend. 19
4.1.3 Non‐Utility Entity
If NVC identified a non‐utility market for electricity from a project at Jack River, it may be able
to directly sell energy to that market. Under state regulations, there are two general options
for such an arrangement:
17 Non‐fuel expenses for Tok‐Tanacross, which has a similar electric load as the Cantwell area, were $0.121 per
kWh in FY 2011, compared with $0.023 per kWh for GVEA (PCE Program Statistical Report, FY 2011, AEA).
18 See Article 4 of the ‘Amended and Restated Alaska Intertie Agreement’, November 18, 2011.
19 Five of the six railbelt utilities formed the Alaska Railbelt Cooperative Transmission and Electric Company
(ARCTEC) in 2011 to focus on centralized planning and ownership of railbelt generation and transmission
projects.
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1. Sale to less than 10 independent end users that are not within an existing certificated
utility service area is not regulated by the RCA. Figure A‐2 shows the extent of GVEA’s
existing certificated service territory around Cantwell.20 To reach such markets, NVC
would need to arrange for wheeling over power lines owned by GVEA, AEA, and possibly
other utilities, or build dedicated power lines to serve these customers.
Potential examples of the market include mines, lodges, resorts, or similar businesses
operating in the vicinity of Cantwell. This business model would need to consider the
market demand for electricity and the supply capability of the selected hydro project.
Mismatches between demand and supply could potentially be met by sale or purchase
of energy from GVEA. This business model would require detailed analysis to verify a
specific project business plan complied with existing statutes and regulations.
2. Sale to affiliated interests of the hydro project owner. Under this structure, NVC (or its
subsidiary owning the hydro project) could sell electricity to affiliated interests located
within an existing utility service territory in certain limited situations. A specific business
plan would require detailed analysis to determine if it complied with RCA regulations.
3. Direct sale of electricity to un‐affiliated entities within an existing utility service area is
not allowed under RCA regulations. Some electricity markets in the Lower 48 have been
deregulated to allow such direct sales, but Alaska remains a regulated market where
such activities are not allowed.
20 The RCA approved a modification to GVEA’s service territory boundaries in the Cantwell vicinity in September
2012. See RCA Docket U11‐127. Figure A‐2 reflects the new service territory boundaries in the project area.
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4.2 POTENTIAL MARKETS
4.2.1 Local Market – Cantwell and Surrounding Areas
Existing local demand in Cantwell and surrounding areas could be served year‐round by a
hydroelectric project with generating capacity of 2+ MW and sufficient storage to generate
3,000 MWh through the winter season. All project configurations at Dam Site #1 and #2 meet
these criteria, and configuration 3A at Dam Site #3 meets this criteria. Most project
configurations at Dam Site #2 and #3 would require careful reservoir management in order to
supply all of the area’s energy needs through the winter season.
Alternately, because Cantwell is connected to the railbelt grid, the storage requirement can be
reduced to 450 MWh, which is the approximate amount needed to serve Cantwell and
surrounding areas through a week‐long outage at any time of year. The balance of Cantwell’s
energy demand during the winter months would be imported via the AIS as is current practice.
All project configurations except for 3C meet this criteria. Configuration 3C could meet local
demand for approximately two days during the summer months, and for approximately ten
days in the winter months. The project would need to be routinely operated with a full
reservoir in order to supply local energy demands during an intertie outage.
4.2.2 Railbelt Market
The railbelt is the largest single electric market in Alaska, and is capable of receiving the full
output of a Jack River hydro project. The railbelt presents a wide variety of interesting market
opportunities and challenges for the NVC’s consideration. The feasibility of the railbelt utilities
purchasing electricity from Jack River depends on the price of the electricity and the particular
utility’s energy cost structure.
While the railbelt is interconnected, it is not an integrated market. Different sections of the
railbelt transmission system are owned by different entities, and there are several technical and
contractual bottlenecks that restrict flow of power within the railbelt. Many of the utilities are
subject to all‐requirements or some‐requirements power supply contracts that limit the ability
of an IPP to sell electricity on a wholesale basis. The result is a very complicated technical and
legal ‘patchwork’. The railbelt electric utilities are currently in a cycle of capital reinvestment
and structural reform, which may simplify this patchwork over the next 5 to 10 years.
4.2.2.1 GVEA
Because Cantwell is located within GVEA’s service territory, GVEA is the most logical purchaser
of electricity from Jack River. Also, GVEA currently has the highest avoided energy cost of the
six railbelt electric utilities, so it could afford to pay more than other railbelt utilities for Jack
River’s electrical output.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 27
There are several energy projects in various stages of development that could lower GVEA’s
energy costs, adversely affecting this market for a Jack River project. Some of these projects
are listed in Table 4‐1.
Table 4‐1: Proposed Alternative Energy Supplies for GVEA
Resource / Project
Proposed
Operational
Date
Proposed
Energy Price
(2012 $)
Probable Impact on GVEA Avoided Cost Structure
Eva Creek Wind Farm (1) Fall 2012 $0.086 per
kWh
Projected output is approximately 4% of total GVEA
supply. Will result in modest decrease in energy
costs if performance forecasts are achieved.
New Natural Gas Finds
in Cook Inlet 2014 – 2016 NA
Neutral. Extends the status quo of GVEA purchasing
economy energy from ML&P and CEA. If these finds
do not result in significant new natural gas reserves,
GVEA’s avoided cost of energy will increase as low‐
cost energy purchases from Cook Inlet‐area utilities
decrease.
Start Up of Healy Clean
Coal Plant (2) 2014 $0.11 per
kWh
Assuming 75% of plant output displaces diesel and
naptha consumption, would reduce system average
avoided cost approximately 12%
Trucking LNG from
North Slope 2015 $12.2 per
kWh (3)
Assumed to eliminate all diesel and naptha
consumption, which would reduce incremental
avoided cost approximately 35%, and system
average avoided cost approximately 20%.
Alaska Stand‐Alone Gas
Pipeline (ASAP) 2018 / 2019 $0.094 per
kWh (4)
Assumed to eliminate all diesel and naptha
consumption, which would reduce incremental
avoided cost approximately 50%, and system
average avoided cost approximately 25%.
Susitna‐Watana
Hydroelectric Project 2024 $0.17 per
kWh (5)
Assumed to eliminate all diesel and naptha
consumption, reducing incremental avoided cost
approximately 10% and system average avoided cost
approximately 5%.
Trans‐Canada Gas
Pipeline Unknown Unknown Too many unknowns to speculate. Likely similar to
other gas supply projects listed in this table.
(1) Based on Eva Creek Project information on GVEA website: www.gvea.com/energy/evacreek
(2) Based on an October 3, 2012 article in the Fairbanks Daily News‐Miner.
(3) Based on low‐end of range of delivered cost for LNG in Fairbanks ($13.60 per MCF) as forecast in January 10,
2013 presentation to AIDEA Board of Directors. Converted to price per kWh using assumed net heat rate of
9,000 btu/kWh.
(4) Based on an assumed net heat rate of 9,000 btu/kWh and delivered natural gas cost in Fairbanks of
$10.45/MCF. (ASAP Project Plan, Alaska Gasline Development Corporation, July 2011).
(5) Based on information in January 10, 2013 presentation to AIDEA Board of Directors.
All of these projects have some degree of risk and uncertainty. With the exceptions of the Eva
Creek wind farm, which is nearly completed and partially operational, and possibly the Healy
Clean Coal Plant, which is built but has been shut down for over a decade, it is unknown if or
when any of these projects will be built, or whether the estimated budgets will be met and
reduced energy costs for GVEA will be realized.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 28
4.2.2.2 Other Railbelt Utilities
Electricity from Jack River could be sold to one or more of the other five railbelt utilities. These
are:
● Matanuska Electric Association, Inc. (Eagle River and Matanuska‐Susitna Valleys)
● Chugach Electric Association, Inc. (Southern Anchorage and northern Kenai Peninsula)
● Anchorage Municipal Light and Power (Northern Anchorage)
● Seward Electric System (City of Seward)
● Homer Electric Association (Southern Kenai Peninsula)
All of these utilities currently have lower energy costs than GVEA, so they would not be
expected to pay as much as GVEA for Jack River’s output. Additionally, delivering energy to
these utilities would incur wheeling costs over the AIS, and potentially MEA, ML&P, or CEA
transmission systems, decreasing the net revenues from the project.
Table 4‐2 provides some examples of existing transmission wheeling rates on the railbelt grid.
Table 4‐2: Selected Railbelt Grid Wheeling Costs
Energy
Customer
Transmission
Line Owner Transmission Description and Location Transmission
Line Length Wheeling Cost
GVEA AEA Wheeling Bradley Lake Energy over the AIS
(MEA’s Douglas Substation to Healy) 170 miles $0.0257
per MWh‐mile
GVEA MEA Wheeling Bradley Lake Energy over MEA System
MEA’s Teeland Substation to Douglas Substation) 19 miles $0.0242
per MWh‐mile
GVEA CEA
Wheeling Bradley Lake Energy over CEA system
from Kenai Peninsula to Anchorage (Dave’s Creek
Substation to Rutherford Substation in Anchorage)
98 miles $0.0316
per MWh‐mile
Wheeling costs derived from GVEA filings in RCA Docket TA230‐13.
4.2.2.3 Individual Customers
Sale to individual customers is possible if the total number of customers is less than ten and
they are located outside of an existing utility’s certificated service area (the limits of GVEA’s
service area in the project vicinity are shown on Figure A‐2). If the customers are located within
the utility’s certificated service area, direct sale is generally not allowed, as it would violate the
terms of the certificate of public convenience and necessity granted to the utility by the RCA.
GVEA’s existing certificated service territory includes the Parks Highway corridor from Cantwell
north to Fairbanks.
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5.0 CONCLUSIONS AND RECOMMENDATIONS
Reconnaissance‐level investigations of Jack River conclude that several hydroelectric project
configurations appear to be technically viable at Jack River, ranging in installed capacity from
approximately 1.7 to 7.3 MW. All project configurations considered for Jack River are storage
projects. The 1.7 MW project would only have sufficient storage capacity to supply Cantwell
and surrounding areas during a week‐long intertie outage, whereas the 7.3 MW project would
have sufficient storage capacity to fully regulate Jack River flow on an annual basis.
The most accessible market for the electric output of a hydro project at Jack River is wholesale
purchase of the full electrical output of the project by Golden Valley Electric Association, Inc.
(GVEA), the local electric utility. Under existing market conditions and estimated site
conditions, the project configurations considered in this study are not economic with wholesale
purchase at GVEA’s current system average avoided energy cost. Under more favorable
financing, site, and/or market conditions, several of the project configurations evaluated in this
study appear to be economically viable with wholesale purchase of the electricity by GVEA.
Project configurations that appear to warrant further study have estimated benefit‐cost ratios
of between 0.50 and 3.00. This wide range incorporates a +/‐ 30% range on total installed cost,
and a range of operating costs and financing terms.
Initial analysis of environmental impacts associated with the project configurations considered
indicates they would affect resident fish that are likely present in Jack River by impeding fish
passage through the project reach and by changing water quantity and quality downstream of
the project. Alaska’s Fishway Act (AS 16.05.841 to 851) would require that a project at Jack
River either provide for fish passage, provide for hatchery operations to replace the value of
the impacted fisheries, or provide a lump‐sum cash payment as mitigation for fish passage
impacts. In practice, ADF&G prefers to maintain existing habitat, and only rarely accepts
hatchery funding or cash payments in‐lieu of on‐site mitigation.
The project configurations are not expected to significantly impact anadromous fish habitat.
The nearest anadromous habitat is more than 50 miles downstream in the Nenana River near
Healy, and the project could reduce flow at the upper limit of anadromous habitat by up to
approximately 7%. Peak project operation in late winter could increase flow at the upper limit
of anadromous habitat by approximately 50% from natural flow conditions. Proper discharge
ramping rates and thermal management of water releases would likely avoid any impacts to
anadromous habitat.
Reservoirs under some project configurations would inundate up to several hundred acres of
wetland and upland habitat for game along Jack River.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 31
2011 2012 2013 2014 2015 2016 2017 2018
ACTIVITY 12341234123412341234123412341234
Reconnaissance Study
Feasibility Study
Conceptual Design
Permitting
Project Design
Construction Plan
Financing Plan
Construction
Project Commissioning
Construction Phase Close‐out
Based on the findings of this study, further investigation of hydroelectric development on Jack
River should focus on the following information in order to determine if a hydroelectric project
at Jack River is feasible:
● Collect additional hydrology data to better characterize resource hydrology.
● Market analysis to determine a preferred project configuration.
● Perform geotechnical investigations to assess technical suitability of dam sites and
define design parameters for dams.
● Conduct baseline fisheries survey to determine what resident species are present in the
study reach of Jack River.
● Hold scoping meetings with regulatory agencies to outline the scope of environmental
studies, define likely mitigation requirements for aquatic, wetland, and upland impacts,
and determine likely operational constraints on the project.
● Generate refined estimates of electrical output and project costs to determine
economic feasibility.
5.1 DEVELOPMENT PLAN AND SCHEDULE
The next step in the development of a hydro project at Jack River is to perform a feasibility
study to validate and build on the reconnaissance‐level findings in this study. The feasibility
study would focus on collecting more field data to better define the hydroelectric resource and
potential environmental and regulatory constraints that may be imposed on the project’s
operations. Once these parameters are better defined, a new economic analysis can be
performed to evaluate the project’s economic feasibility.
The proposed development schedule for the project is presented in Figure 5‐1. Figure 5‐1
assumes that the preferred project configuration identified in the feasibility study does not fall
under Federal Energy Regulatory Commission (FERC) jurisdiction, and can be built in two
construction seasons. If the project requires a FERC license, or requires three construction
seasons, the overall project development schedule will be longer.
Figure 5‐1: Project Development Schedule
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March 2013 – Final Report 32
6.0 REFERENCES
Alaska Department of Commerce, Community, and Economic Development (ADCCED). 2012.
Cantwell. Web site: http://www.commerce.state.ak.us /dca/commdb/CIS.cfm?
Comm_Boro_name=Cantwell
ADCCED, Division of Energy and Power Development, October 1977. Alaska Regional Energy
Resources Planning Project, Phase I, Volume II: Inventory of Oil, Gas, Coal, Hydroelectric,
and Uranium Resources, Final Report.
ADCCED, Division of Energy and Power Development, 1980. Alaska Regional Energy Resources
Planning Project, Phase II: Coal, Hydroelectric, and Energy Alternatives Volume II:
Hydroelectric Development.
ADCCED, Statewide Digital Mapping Initiative. 2012. Web site:
http://www.alaskamapped.org/sdmi
Alaska Energy Authority (AEA). 2010. Railbelt Integrated Resource Plan. Prepared by Black &
Veatch, Inc.
AEA. 2011. November 18, 2011. Amended and Restated Alaska Intertie Agreement.
AEA. 2012a. Renewable Energy Fund Round 6. Web site:
http://www.akenergyauthority.org/RE_Fund‐6.html. July.
AEA. 2012b. Susitna‐Watana Hydroelectric Project Website: http://www.susitna‐
watanaydro.org
AEA. 2012c. Board Resolution 2012‐02.
AEA. 2012d. PCE Program Statistical Report for Fiscal Year 2011.
AEA. 2013a. Presentation to the AIDEA Board of Directors on the Susitna‐Watana
Hydroelectric Project. January 10, 2013.
AEA. 2013b. Presentation to the AIDEA Board of Directors on the North Slope LNG to
Fairbanks Project. January 10, 2013.
Alaska Gasline Development Corporation. 2011. Alaska Stand Alone Gas Pipeline / ASAP:
Project Plan. July 1, 2011.
U.S. Department of the Interior, Bureau of Land Management. June 2006. East Alaska
Proposed Resource Management Plan and Environmental Impact Statement.
Fairbanks Daily News‐Miner, October 2, 2012 Edition. “Deal reached to restart Healy Clean Coal
Plant”
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report 33
Golden Valley Electric Association, Inc. 2012a. Eva Creek Wind Farm Project Web site:
http://www./gvea.com/energy/evacreek
Institute of Social and Economic Research (ISER), University of Alaska Anchorage. 2012b.
Alaska Fuel Price Projections 2012‐2035. ISER Working Paper 2012.1 and Microsoft
Excel Spreadsheet Price Model. July.
Regulatory Commission of Alaska (RCA). 1997a. Docket U‐97‐139, Order No. 2.
RCA. 2008. Docket U‐08‐102. Order No. 2.
RCA. 2011a. Docket U11‐100. Order No. 5.
RCA. 2011b. Docket U11‐111. Order No. 2.
RCA. 2011c. Docket U11‐127.
RCA. 2012. Docket TA230‐13.
U.S. Geological Survey (USGS). 2003. Estimating the Magnitude and Frequency of Peak
Streamflows for Ungaged Sites on Streams in Alaska and Conterminous Basins in
Canada: Water‐Resources Investigations Report 2003‐4188. By Curran, Janet H.; Meyer,
David F.; and Tasker, Gary D.
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APPENDIX A – MAPS AND FIGURES
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Figure A‐1: Project Overview and Location Map
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Figure A‐2: General Land Ownership in Project Vicinity
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Figure A‐3: Map of Hydrology Basins and Sub‐Basins
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March 2013 – Final Report A‐4
Figure A‐4: Hydro Project Configuration 1A at Dam Site 1
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Figure A‐5: Hydro Project Configuration 2A at Dam Site 2
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Figure A‐6: Hydro Project Configuration 3A at Dam Site 3
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APPENDIX B – PHOTOGRAPHS
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Photograph B‐1: Stream Gauging
Station Installation, November 2011
Photograph B‐2: Bank Erosion at
Stream Gauging Station, May 2012
View looking upstream at stream
gauging station installed November 2,
2011.
Brailey Hydrological Consultants,
November 2, 2011
View looking upstream at stream gauging
station during spring runoff installed
November 2, 2011. Note bank erosion
since installation (Photo B‐1)
Photo Courtesy of Calvin Carlson,
June 6, 2012.
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report B‐2 Photograph B‐3: View Downstream Towards Cantwell from Gauging Station Photograph B‐4: View Upstream Towards Dam Site 3 from Vicinity of Gauging Station View looking upriver towards dam site #3 from rock outcrop on left bank of Jack River overlooking gauging station. Brailey Hydrological Consultants, November 3, 2011 GAUGING STATIONView looking downriver from rock outcrop on left bank of Jack River. Brailey Hydrological Consultants, November 3, 2011 DAM SITE 3
Native Village of Cantwell
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Photograph B‐5: View of Jack River Canyon Near Dam Site 1
View of Jack River canyon from Wolf Point. Proposed Dam Site 1 is located just
downstream of the tributary visible in the photograph. Jack River is running from left to
right in this photograph.
Polarconsult, July 22, 2012
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report B‐4 Polarconsult, July 23, 2012 Polarconsult, July 22, 2012 Photograph B‐6: Panoramic View of Jack River Canyon From Wolf Point, Looking SW Photograph B‐7: Panoramic View of Jack River at Stream Gauging Site, Looking Upriver
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report B‐5 Photograph B‐8: Panoramic View of Dam Site 2, Looking Southwest Photograph B‐9: Panoramic View of Dam Site 1, Looking Northwest View of dam site 2 from the right rim of the Jack River valley. The brown line traces the approximate alignment of the proposed dam site. Jack River is flowing from left to right in this photograph.Polarconsult, July 23, 2012View looking downstream at dam site 1. The brown line traces the approximate alignment of the proposed dam site. The community of Cantwell is located in the distance.Polarconsult, July 23, 2012
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
APPENDIX C – HYDROLOGY DATA
C.1: Introduction and Methodology pages C‐1
C.2: Stream Gauge Station Information pages C‐2 to C‐4
C.3: Comparable Basins page C‐5
C.4: Jack River Hydrology Model page C‐6 to C‐9
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C.1 INTRODUCTION AND METHODOLOGY
Jack River hydrology information is used to identify the appropriate installed capacity of the
hydroelectric project, evaluate the expected electrical generation potential of the project,
evaluate storage configurations for the project, and determine the magnitude of flood flows on
Jack River. Moreover, this hydrology information can help assess the effect the project may
have on the natural environment.
Hydrology information for Jack River is based on (1) a stream gauging station installed just
below the exit of the canyon at RM 11.34 and (2) comparison of data from this gauging station
to data for nearby comparable basins with existing or historical hydrology records. By analyzing
Jack River data in conjunction with data from nearby rivers with longer periods of record, a
better estimate of the long‐term hydrology of Jack River can be developed. This allows for
better estimates of the project’s long‐term performance.
Approximately 11 months of hydrology data have been collected at Jack River and analyzed for
this project. The gauging station below the river valley remains in service and is described in
Section C.2. This Appendix summarizes the hydrology data and analysis used for this study.
Appendix I provides the daily stage and calculated flow data in tabular form.
C.2 STATION INFORMATION
C.2.1 STATION SETTING
The location of the gauging station is shown on Figure A‐3 and Photographs B‐1, B‐2, B‐4 and B‐
7. Stream morphology at the gauging station is a continuous riffle running at the grade of the
alluvial plain, which is approximately 0.6% to 0.8%. There are a series of overflow channels on
the left bank (inside bend) and at a higher elevation on the right bank (outside bend).
Approximately 100 feet upstream of the gauging station, the fan is confined to a width of 400
to 1,200 feet by the river valley’s walls, which are a mix of weathered bedrock and glacial till
with some unconsolidated overburden (see Photographs B‐7 and B‐9). Immediately
downstream of the gauging station, the valley walls open up and transition to bluffs with
occasional bedrock outcrops. Approximately ¼ mile downstream of the gauging station, the fan
opens up to the valley between the Nenana River and Broad Pass, and is effectively laterally
unconfined. Proximity to the river valley and visual assessment of site geology suggests that
surface flow at the gauging station is representative of surface flows within the canyon.
Significant infiltration to groundwater is possible downstream of the gauging station.
Significant groundwater flow may also occur through the unconsolidated sediments that cover
the valley floor at and above the gauging station.
C.2.2 STATION INSTALLATION
On November 2, 2011, Polarconsult subcontractor Brailey Hydrological Consultants (BHC)
supervised installation of a new gauging station near the outlet of the Jack River valley. The
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March 2013 – Final Report C‐2
gauging station is a 6‐inch steel well casing installed in the active plain of Jack River where it
emerges from its valley and onto the floor of Broad Pass. At the time of installation in
November 2011, the well was located approximately five feet from the top of the right bank of
the main channel of Jack River along an outside bend. The well casing was set approximately
7.5 feet above ground surface (AGS), and extends approximately 20 feet below ground surface
(BGS). The bottom of the well casing is open ended, and the casing is perforated from the
casing bottom up to approximately seven feet BGS. The top of the casing is fitted with a bolt‐
on steel plate.
A Keller Acculevel series vented pressure and temperature transducer (PTT) is deployed down
the well to record water stage and temperature. The PTT is fitted to a Keller GSM‐2 cellular
enabled data logger that is mounted in the top of the well casing. The data logger records
water stage and temperature data at 15‐minute intervals and emails this data to Polarconsult
once daily.
C.2.3 STATION HISTORY
The gauging station operated continuously from November 2, 2011 through February 17, 2012.
On February 17, 2012, the frost line reached the PTT in the well, approximately 9.5 feet BGS.
Calvin and Gordon Carlson of Cantwell made several attempts to thaw the well and recover the
sensor, but were unsuccessful. The pressure increase associated with the freezing action
exceeded the mechanical limits of the PTT on February 24, 2012, destroying the PTT.
BHC fitted the data logger with a replacement Acculevel PTT on March 27, 2012. The PTT was
not deployed down the well due to continued freezing conditions. Calvin Carlson deployed the
sensor on May 20, 2012 after the well thawed. Calvin Carlson visited the gauging station on
June 6th, and reported that Jack River was actively eroding the right bank, and the gauging well
was now located in mid‐channel.
Polarconsult engineer Joel Groves visited the site July 22 to 24, 2012. At that time, the channels
at the gauging station were quasi‐stable, with a new 55‐foot wide channel to the right of the
gauging well, and a 35‐foot wide channel to the left of the gauging well. There was a brush pile
upstream of the well that was helping to form a shallow cobble bar downstream of the well.
Additional channel shifting likely occurred during the flood events of September 20 to 23, 2012,
based on review of the stage data from the gauging station. Continued channel shifting at the
gauging station is likely during future high flow conditions.
It appears that the main channel of Jack River will eventually cross the well as Jack River
continues to meander. The bottom of the main channel appeared to be approximately 84 to 86
feet in the station datum during the July site visit, suggesting that the well will retain
approximately 11 to 13 feet of casing embedment in the stream bed as the main channel
meanders across the station location.
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C.2.4 FLOW MEASUREMENTS AND STATION CALIBRATION
Flow measurements at the Jack River gauging station are summarized in Table C‐1.
Table C‐1: Jack River Flow Measurements
Date/Time Party Flow
(cfs)
Stage
(ft) Method / Equipment
11/3/2011 11:30 Brailey 0 83.7 Estimated (1)
11/3/2011 11:30 Brailey 63.5 87.73 Current velocity (2)
3/27/2012 14:00 Brailey 29.6 86.00 Sudden dose salt (3)
7/23/2012 11:30 Groves 0 85.6 Estimated (1)
7/23/2012 11:30 Groves 600 90.60 Current velocity and
visual estimates (4)
(1) November 2011 point of zero flow (PZF) estimated from measured stream bed profile, stream gradient, and
distance between gauge and measurement section. July 2012 PZF estimated from measured stream bed
profile, stream gradient, distance between gauge and measurement section, and visual estimate of depth of
main channel at thalweg.
(2) Current‐velocity stream flow method with March McBirney FlowMate 2000 current velocity meter.
(3) Sudden dose salt integration stream flow method with Hanna HI 9828 conductivity meter.
(4) Stream depths and velocities were unsafe to perform a complete measurement with available equipment.
One of two main channels at the gauging station were measured using the current‐velocity method, and the
depths and velocities in the 2nd channel were visually estimated. The width of the 2nd channel was surveyed
using a reflectorless total station. Minor flow over the outwash fan and in a channel that bifurcates from the
main channels approximately 200 yards upstream of the gauge were also visually estimated.
To calibrate the gauging station, two flow measurements were taken on November 2, 2011 and
March 27, 2012. The point of zero flow was also measured on November 2nd. These three data
points are sufficient to develop a rating curve for the gauging station that is valid from
November 2, 2011 through approximately June 1, 2012 (Figure C‐4).
Review of stage data indicates that Jack River started shifting its channel with the on‐set of
peak spring melt flows between May 24th and June 1st. Peak flows had subsided by July 1st. The
changed channel invalidated the stage discharge curve developed during the winter of 2011‐12.
A new stage‐discharge curve was started with the July 23, 2012 flow measurement and
estimated point of zero flow (PZF).
The flood events of September 21 to 23, 2012 likely resulted in additional channel shifting at
the gauging station, based on review of the stage record. No flow measurements have been
taken to establish an initial rating curve for the station after September 23rd, and this stage data
is not used for the reconnaissance study analysis.
The flow measurements taken for this study are adequate to develop stage‐discharge curves for
the gauging station suitable for reconnaissance‐level analysis. On‐going river meanders at the
gauging station will require continued frequent flow measurements to maintain a valid rating
curve for the gauging station.
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March 2013 – Final Report C‐4
C.2.5 FUTURE GAUGING EFFORTS AT JACK RIVER
Three prospective gauging station locations were considered along Jack River for this study.
These sites, the rationale for selection of the RM 11.34 site, and recommendations for future
gauging efforts at Jack River are discussed below.
Location 1. In the canyon in the vicinity of RM 15. There are exposed rock outcrops and
well‐confined stream channels in this reach that are likely to be more stable than the
selected gauging station at RM 11.34. This would be a relatively remote installation that
would be very difficult to access for installation, flow measurements, or station
maintenance. This site would most likely not have cellular or satellite coverage due to
the steep canyon terrain, requiring on‐site data storage and introducing the risk of data
loss in the event the station hardware was destroyed in a flood or landslide.
Consideration of these factors in concert with the limited funds available for this study
precluded use of this site.
Location 2. The selected gauging station. The site at RM 11.34 is immediately downstream
of the canyon outlet, and is believed to accurately characterize surface flow in Jack River
at the prospective dam sites. The site is readily accessible, and has cellular coverage for
a telemetered installation. Active meandering of Jack River was a known risk with this
site (hence the decision to house the installation in a steel well casing), and turned out
to be worse than anticipated for the 2011‐12 gauging campaign.
Location 3. Gauging stations at either the Parks Highway Bridge (RM 9.51) or the Denali
Highway Bridge (RM 7.21) over Jack River. Both sites would be readily accessible and
would have cellular coverage. The primary limitation of these sites is that Jack River
traverses two to four miles of alluvial plain between RM 11.5 (Dam Site #3) and these
sites. A significant fraction of the surface flow at RM 11.5 may percolate into the alluvial
substrate upstream of RM 9.51 and 7.21, resulting in a potentially significant
underestimate of the flow available for hydropower generation. This concern led to
exclusion of these sites for this study.
Based on experience from the 2011‐12 stream gauging campaign, future stream gauging efforts
should either (1) continue the use of the RM 11.34 site, but budget for frequent flow
measurements through the summer season to recharacterize the site after channel shifting
events, or (2) install a new gauging station at one of the two downstream bridge sites, and
conduct a series of concurrent flow measurements to quantify differential flow between the
downstream gauging station and the prospective dam site(s). The hardware at the RM 11.34
gauging station remains in working order and can be moved to a new station location.
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C.3. COMPARABLE BASINS
Generally, 5 to 10 years of site‐specific hydrology data is needed to make well‐informed
decisions for hydroelectric development. However, if a gauge with a long‐term record
correlates well with the shorter record at Jack River, the longer record can be used to extend
the shorter record through a regression analysis.
Existing available hydrology data in the vicinity of Jack River is summarized in Table C‐2. Of the
seven rivers and streams listed in Table C‐2, only the Susitna River at Gold Creek gauging station
(USGS gauge No. 15292000) is currently operational. Because of the reasonable proximity,
concurrent record, and long period of record for this station, it is used to create an extended
record for Jack River.
Table C‐2: Summary of Jack River Hydrology Data
Location USGS
Gauge ID
Basin
Size
(sq.mi.)
Site
Elevation
(ft) (1)
Latitude(1) Longitude(1) Begin
Date
End
Date
Number
of Daily
Records(2)
Jack River
below canyon N/A 145 2,480 6320’N 14846’W 11/2/11 Current 212
Seattle
Creek 15515800 36.0 2,250 6319’N 14815’W 10/1/65 9/30/75 3,651
Susitna at
Gold Creek 15292000 6,160 676 6246’N 14941’W 8/1/49 Current 23,059
Nenana R nr
Windy 15516000 710 2100 6327’N 14848’W 6/16/50 9/30/73 8,513
Nenana R nr
Healy 15518000 1,910 1,270 6351’N 14857’W 10/1/50 9/30/79 10,598
Nenana R at
Healy 15518040 2,100 1,350 6315’N 14857’W 4/24/90 9/30/07 6,372
Lignite C ab
Mouth nr
Healy
15518080 48.1 1,300 6354’N 14859’W 5/30/85 9/30/04 7,068
Teklanika R
nr Lignite 15518350 490 1550 6355’N 14930’W 10/1/64 9/30/74 3,654
(1) Coordinates for USGS gauges are in North American Datum of 1927 (NAD 27). All other coordinates are in NAD
83. Elevations for USGS gauges are from the USGS, elevations for other sites are interpreted from USGS quad
maps. Elevation for the Jack River station is an orthometric height in NAVD88, computed using GEOID12.
(2) The record count for current gauging stations reflects data through August 31, 2011.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report C‐6
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Nov 1Nov 29 Dec 27 Jan 24 Feb 21 Mar 20 Apr 17Normalized Flow (cfs/sqmi)1949‐2012 Winter Flow Measurements, Susitna River at Gold Creek
1975‐2012 Winter Flow Measurements, Susitna River at Gold Creek
2011‐2012 Winter Flow Measurements, Susitna River at Gold Creek
Measured Flow, Jack River Gauge
Calculated Flow, Jack River Gauge
C.4 JACK RIVER HYDROLOGY MODEL
A model was developed based on available data to approximate the hydrology of Jack River.
● Summer flows (June 1 through August 15) are based on data from USGS Gauge #15292000,
Susitna River at Gold Creek. The relatively good correlation between available data for Jack
River (June 4, 2012 to August 1, 2012) and this station (coefficient of determination (R2) =
0.78) suggests that this is a good model for summer‐time flows in Jack River.21 Equation C‐1
provides the summer model.
Equation C‐1: Q Jack = 0.000882 x Q Susitna + 326.7
Q Jack = Jack River flow; Q Susitna = Susitna River flow at Gold Creek.
● Winter flows (November 1 through April 30) are based on gauged Jack River flows for the
2011‐12 winter. To evaluate whether flow during the winter of 2011‐12 was average, 2011‐
12 winter flow measurements on the Susitna River at Gold Creek were reviewed. Figure C‐1
shows winter flow measurements on the Susitna River from 1949‐2012. Susitna
measurements since 1975 and for the 2011‐12 winter are highlighted. The two
measurements for the winter of 2011‐12 appear generally representative of winter flows
for the 37‐period of record 1975‐2012, so no adjustments to the Jack River record appear
warranted. Equation C‐2 provides the winter model.
Equation C‐2: Q Jack = 0.01995 x Q Susitna
Figure C‐1: Winter Flow Measurements at Jack River and Susitna River
21 Because of the scarcity of hydrology data in Alaska, a correlation coefficient of 0.78 between these basins is
considered good. In other regions of the United States, this coefficient may be considered marginal. Also, the
short period of common record limits the confidence of this finding.
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report C‐7
0
1
2
3
4
5
6
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecCFS per Square Mile of BasinSeattle C nr Cantwell (15515800)
Nenana R nr Windy (15516000)
Nenana R nr Healy (15518000)
Nenana R at Healy (15518040)
Teklanika R nr Lignite (15518350)
Susitna at Gold Creek (15292000)
Jack River Model
● Spring Flows (April 30 through June 1) are calculated by a linear weighted average of the
summer and winter models. The winter model receives 100% weighting on April 30,
decreasing linearly to 0% on June 1. The summer model increases in a similar fashion.
● Fall flows (August 15 through November 1) are calculated by a linear weighted average of
the summer and winter models. The summer model receives 100% weighting on August 15,
decreasing linearly to 0% on November 1. The winter model increases in a similar fashion.
The resulting Jack River hydrograph for an average water year is shown in Figure C‐2 along with
average hydrographs for several other basins in the vicinity of Jack River.
Figure C‐2: Jack River Hydrology Model
This hydrology model is based on limited hydrology data, and should be reevaluated when
more data is available from the Jack River stream gauging station. This model is sufficient for a
reconnaissance‐level analysis of Jack River. Figure C‐3 presents the flow duration curve for Jack
River (based on the hydrology model) and for the Susitna River at Gold Creek.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report C‐8
0
1
2
3
4
5
6
7
8
9
10
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percentage of Time Flow is Equalled or ExceededNormalized Flow (cfs per square mile)Susitna at Gold Creek
Jack River Model
85.0
86.0
87.0
88.0
89.0
90.0
91.0
92.0
0 100 200 300 400 500 600 700
Jack River Discharge at Gauging Station (cubic feet per second)Stage (Top of Well Casing = 100 feet)Winter 2011‐12 Stage‐Discharge Measurements
Summer 2012 Stage‐Discharge Measurements
Poly. (Winter 2011‐12 Stage‐Discharge Measurements)
Figure C‐3: Flow Duration Curve for Jack River
Figure C‐4: Stage‐Discharge Data for Jack River Gauging Station
Native Village of Cantwell Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc. March 2013 – Final Report C‐9 ‐40‐2002040608010011/1/11 12/6/11 1/10/12 2/14/12 3/20/12 4/24/12 5/29/12 7/3/12 8/7/12 9/11/12 10/16/12 11/20/12 12/25/12 1/29/13 3/5/13Temperature (F)Station Water Temperature (F)Station Air Temperature (F) Figure C‐5: 2011 – 2012 Jack River Stage Data Figure C‐6: 2011 – 2012 Jack River Gauging Station Air and Water Temperature Data Figure C‐5: 2011‐2012 Jack River Stage DataFigure C‐6: 2011‐2012 Jack River Gauging Station Air and Water Temperature Data83.5084.5085.5086.5087.5088.5089.5090.5091.5092.5093.5011/1/11 12/6/11 1/10/12 2/14/12 3/20/12 4/24/12 5/29/12 7/3/12 8/7/12 9/11/12 10/16/12 11/20/12 12/25/12 1/29/13 3/5/13River Stage at Gauging Station(Top of Casing = 100.00 feet) Water Stage, Logger Reading (ft)Water Stage, Manual Reading (ft)
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
APPENDIX D – RESOURCE DATA AND ANALYSIS
D.1: Land Status page D‐1
D.2: Maximum Probable Flood pages D‐1 to D‐2
D.3: Reservoir Life pages D‐3 to D‐6
D.4: Cantwell Outage Rate page D‐7
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report D‐1
D.1 LAND STATUS
General land status of the project area is shown in Figure A‐2. In summary, most of the land
where development would occur for the hydro project (site access roads, power line,
powerhouse, dam, tunnels, penstocks, and intake structure) have been either patented to,
interim conveyed to, or selected by Ahtna, Inc. With the exception of project configuration 3C,
portions of the proposed reservoirs would be located on land either patented to or tentative
approved for patent to the State of Alaska. Reservoirs above dam site 1 with maximum
elevations greater than approximately 2,615 feet would extend onto federal land (sections 3
and 10 of T19S, R6W, Fairbanks Meridian).
Ahtna, Inc. is aware of and supportive of this project. It is assumed that Ahtna, Inc. would
authorize access and use of the project lands under easements, long term leases, and/or sale to
the native Village of Cantwell. Detailed discussions with Ahtna, Inc. on this matter were not
held for this study.
D.2 MAXIMUM PROBABLE FLOOD
Determining the maximum probable flood for Jack River is important for (1) designing the dam,
spillway, and associated project works so they can withstand flood flows, and (2) evaluating the
potential flood hazard mitigation capabilities of a storage project on Jack River. USGS statistical
models for regional Alaska streams were used to develop initial estimates of the 100‐year and
500‐year flood flows for Jack River. These data are compared against annual peak flows
measured at Jack River by the USGS.
The USGS has developed statistical models to estimate the maximum probable floods for
streams in Alaska. These models are developed based on stream gauging data throughout the
state, and specific parameters for the drainage basin of the stream of interest.22 USGS model
input parameters and estimated flood flows are summarized in Table D‐1.
USGS models for both interior Alaska (Region 6) and southcentral Alaska (Region 4) were
evaluated. Jack River is located in Region 6 close to the border to Region 4. The good
correlation between Jack River and the upper Susitna River (located in Region 4) suggest that
the Region 4 model may provide a better estimate of Jack River’s peak flows.
The USGS recorded a maximum annual flow at Jack River of approximately 4,900 cfs at USGS
Gauge 15516050 over 9 years of peak flow gauging from 1973 to 1982. This gauge is
downstream of the proposed project, and drains 325 square miles. Scaling this peak flow to the
project basin area yields an estimated peak flow of 2,095 cfs over this nine‐year period. This
peak flow is 20 to 40% lower than the estimated 10‐year floods.
The Region 6 model provides higher estimated peak flows, and these are used for the
preliminary designs in this study.
22 See USGS Water Resources Investigation Report 2003‐4188.
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report D‐2
Table D‐1: Maximum Probable Floods at Jack River Hydro Project Site
Parameter Jack River
Basin Area (square miles) 139.1
Mean Annual Precipitation (inches) (1) 30
Percentage of Basin as Storage (lakes, ponds) 0.5%
Percentage of forested area (2) 10%
USGS WRIR 2003‐4188 Estimated Peak Flows Region 4
(Interior)
Region 6
(Southcentral)
(Used for this Study)
Estimated 500‐year flood (Initial Estimate of Design Flood) 5,828 cfs 7,445 cfs
Estimated 100‐year flood 4,461 cfs 5,745 cfs
Estimated 10‐year flood 2,705 cfs 3,487 cfs
Estimated 5‐year flood 2,185 cfs 2,829 cfs
Jack River Maximum Recorded Flow (1973‐1982) (3) 2,095 cfs
(1) Annual precipitation in Cantwell is reported as 15 inches. Source maps specified in the USGS publication indicate
precipitation in the Jack River basin is approximately 30 inches annually.
(2) Estimated from aerial imagery and USGS maps.
(3) Reported at USGS Gauge 15516050 on Jack River near its mouth. Adjusted to project area by ratio of basin areas (0.427 =
139/325 square miles).
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report D‐3
D.3 ESTIMATED RESERVOIR LIFE
All of the hydroelectric project configurations considered in this study are storage projects,
featuring dams that create reservoirs of various capacities in the Jack River canyon. As these
reservoirs accumulate sediment over time, their ability to store water for power generation will
decrease. Eventually, the amount of sediment carried into the reservoir and flushed out of the
reservoir will reach equilibrium. The amount of the active reservoir volume that fills with
sediment can have a significant impact on project operations and total energy output. How
quickly equilibrium sedimentation is reached, and what that equilibrium volume of
sedimentation is, depends on many factors, including:
The rate sediment is carried into the reservoir by Jack River;
The geography of the reservoir, which influences where sediment is deposited and how
much can be scoured out of the reservoir by flushing operations;
The operational regime for the reservoir – how and when it is filled to capacity, drawn
down, minimum drawdown levels, etc.; and
The configuration of the dam and regulatory allowances for reservoir draw down and
sediment flushing operations. Some sediment flushing is normally desirable for recruitment
of sediment in the downstream reach of the river, but flushing schedules and protocols
depend on resource‐specific considerations that are beyond the scope of this study and are
not defined at this time.
The initial, order‐of‐magnitude analysis of reservoir sedimentation indicates that the various
reservoir configurations considered in this study would reach an equilibrium sediment volume
in 10 to 460 years, and the final active volume of the reservoirs would be between 50 and 76%
of the initial active volume. Actual site conditions and final operational protocols for specific
projects may result in actual sedimentation rates that significantly differ from these initial
estimates.
D.3.1 Estimated Sediment Transport Rate
No studies of sediment transport in Jack River are known to exist. To form an initial order‐of‐
magnitude estimate of sediment transport rate, data from studies on the Susitna River basin
were adapted to Jack River.23 Sediment transport rates on the Susitna, Talkeetna, and Chulitna
Rivers were measured ranging from 800 to 1,400 tons per year per basin square mile. These
rates applied to Jack River yield an estimated sediment transport rate of 110,000 to 200,000
tons per year. Assuming a reservoir sediment trap efficiency of 100% and an in‐place density of
75 pounds per cubic foot, this sediment would fill between 70 and 120 acre‐feet of reservoir
annually.
23 Sediment transport data for Susitna River and major tributaries as summarized in Susitna Hydroelectric Project,
Reservoir and River Sedimentation Final Report, FERC No. 7114. Harza‐Ebasco Susitna Joint Venture, April 1984.
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report D‐4
D.3.2 Estimated Reservoir Sedimentation Rate and Location
The fate of the sediment entering the reservoir depends on reservoir geometry and operational
patterns. Also, the impact of the sediment on useful reservoir volume depends on where in the
reservoir the sediment ultimately accumulates. Initial order‐of‐magnitude estimates for these
phenomenon are based on the assumption that the reservoirs would be managed to enter the
winter full, would be drawn down through the winter months, would use peak spring flows to
sluice sediment accumulated in delta deposits at the reservoir inlet deeper into the reservoir
and/or through the dam, and would refill the reservoir with summer and fall flows. Under
these operational assumptions, sediment profile in the reservoirs would take the general form
shown on Figure D‐1 for dam sites 1, 2, and 3. The delta formations shown in Figure D‐1 are
based on a topset slope of 0.3% starting from the reservoir inlet a foreset slope of 2% from the
invert of the dam bypass up to the pivot point of the delta formation.24
Table D‐2 summarizes initial order of magnitude estimates of initial active, inactive, and total
reservoir volume; reservoir sedimentation rates; final active, inactive, and total reservoir
volume once sedimentation reaches a steady state; and the approximate number of years it will
take for the reservoir to reach steady‐state sedimentation conditions.
Table D‐2: Estimated Reservoir Sedimentation Rates and Useful Reservoir Life
Reservoir Configuration Estimated Parameter 1A, 1B 1C 2A, 2B 3A, 3B 3C
Initial Active Reservoir Volume (ac‐ft) 50,700 15,700 25,500 9,300 2,100
Initial Inactive Reservoir Volume (ac‐ft) 28,900 3,500 7,800 5,900 200
Initial Total Reservoir Volume (ac‐ft) 79,600 19,200 33,300 15,200 2,300
Reservoir Volume as Percentage of Total
Annual Flow Volume 1 73% 18% 31% 14% 2%
Annual Sedimentation Rate (ac‐ft) 70 to 120 70 to 120 70 to 120 70 to 120 70 to 120
Reservoir Sediment Trap Efficiency 2 80 to 95% 75 to 90% 80 to 95% 75 to 90% 55 to 65%
Trap Efficiency Used 100% 100% 100% 100% 65%
Final Active Reservoir Volume (ac‐ft)
Final as Percentage of Initial
30,500
60%
10,100
64%
12,900
50%
7,100
76%
1,200
57%
Final Inactive Reservoir Volume (ac‐ft) 17,000 1,300 3,400 2,600 100
Final Total Reservoir Volume (ac‐ft) 47,500 11,400 16,300 9,700 1,300
Reservoir Life (years) 270 to 460 65 to 110 140 to 240 45 to 80 10 to 20
1. Total annual flow volume is 108,595 acre‐feet, based on an average annual flow of 150 cfs.
2. Efficiency range is calculated using the Churchill and Brune methods for lower and upper estimates,
respectively.24
24 Estimated delta parameters are based on methods described in Section 2.6 of the Erosion and Sedimentation
Manual. U.S. Bureau of Reclamation, November, 2006.
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report D‐5
75 pcf
2200
2250
2300
2350
2400
2450
2500
2550
2600
11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00 15.50
River MileElevation (feet)Natural River Grade
Maximum Pool Elevation
Estimated Equilibrium Level of Sediment in Reservoir
Minimum Normal Pool Elevation
2400
2450
2500
2550
2600
2650
2700
2750
2800
12.50 13.50 14.50 15.50 16.50 17.50 18.50 19.50 20.50
River MileElevation (feet)Natural River Grade
Maximum Pool Elevation
Estimated Equilibrium Level of Sediment in Reservoir
Minimum Normal Pool Elevation
2200
2250
2300
2350
2400
2450
2500
2550
2600
11.00 11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00
River MileElevation (feet)Natural River Grade
Maximum Pool Elevation
Estimated Equilibrium Level of Sediment in Reservoir
Minimum Normal Pool Elevation
DAM SITE 3
DAM SITE 2
DAM SITE 1
Figure D‐1: Estimated Ultimate Reservoir Sedimentation Profile
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March 2013 – Final Report D‐6
D.3.3. Sediment Loading from Reservoir Bank Erosion
Bank erosion along the perimeter of the reservoirs will also contribute to reservoir
sedimentation. The magnitude of this sedimentation depends on how susceptible the banks
are to erosion, and where the eroded bank material settles within the reservoir. Initial
estimates are that bank erosion will not contribute significantly to overall reservoir
sedimentation rates.
Initial assessment of site conditions for the dam site 1 reservoir suggest that bank erosion will
not contribute significantly to the overall reservoir sedimentation rate. Eroded material along
most of the reservoir perimeter is likely to deposit below the active band of the reservoir. In
the upper approximately 1‐½ miles of the reservoir eroded material is likely to settle in the
active band of the reservoir. However, the bank slopes in this area are generally 1:10 or less,
and therefore less susceptible to erosion than steeper banks elsewhere along the reservoir
perimeter.
Initial assessment of site conditions for the reservoirs above dam sites 2 and 3 suggest that
bank erosion will not contribute significantly to the overall reservoir sedimentation rate. Most
of the reservoir shoreline is exposed weathered rock at slopes of approximately 1:1. Rapid
erosion of this rock is not expected, and eroded material is expected to migrate down these
slopes to the valley floor, which is generally below the active band of the reservoir.
D.3.4 Significance of Reservoir Sedimentation on Project Economics
Table D‐3 summarizes the estimated initial and final annual energy generation of project
configurations considered in this study. Reservoir sedimentation has the greatest relative
impact on configurations 1A and 1B, decreasing annual generation to 88% once equilibrium
sediment levels are reached. Because the estimated time to reach this level of sedimentation
(270 to 460 years) is significantly longer that the timeframe for economic analysis, reservoir
sedimentation is not expected to be a significant factor in project economics.
For all other project configurations, reservoir sedimentation is estimated to reduce annual
energy output to between 94% to 98% of initial output. Because of the modest impact of
sedimentation and the expected time before equilibrium sedimentation is reached, reservoir
sedimentation is not expected to be a significant factor in project economics.
Table D‐3: Estimated Impact of Reservoir Sedimentation on Annual Energy Output
Project Configuration Estimated Parameter 1A 1B 1C 2A 2B 3A 3B 3C
Initial Annual Energy Output (MWh) 37,300 23,400 12,800 17,400 9,300 12,500 7,100 7,500
Final Annual Energy Output (MWh) 32,800 20,600 12,500 16,400 9,100 12,300 7,000 7,400
Final as Percentage of Initial 88% 88% 98% 94% 98% 98% 98% 98%
Estimated Time to Reach Equilibrium
Reservoir Sedimentation (years)
270 to
460
270 to
460
65 to
110
140 to
240
140 to
240
45 to
80
45 to
80
10 to
20
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D.4 ANALYSIS OF POWER OUTAGE RATES
GVEA provided outage data for the Cantwell Substation for 2012. Analysis of this data that the
entire Cantwell service area (Cantwell, McKinley Village, and Carlo Creek) experienced a total of
17 outages with a combined total duration of 8.85 hours in 2012. This does not include outages
to portions of the Cantwell service area due to local distribution interruptions, so total outage
rates in Cantwell and associated communities is somewhat higher than indicated by the data in
Table D‐4. By comparison, the aggregate outage rate over the entire GVEA system has varied
from 1 to 2 hours per customer annually for the past several years. Table D‐4 summarizes 2012
Cantwell outage data and recent GVEA outage data. Based on this information, the outage rate
in Cantwell is approximately 5.3 times higher than for GVEA customers in general.
Table D‐4: 2012 Cantwell Outage Data and Recent GVEA Outage Data
Start and End Times for Outages at Cantwell Substation
(2012)
Outage Duration
(minutes) 1
2/14/12 11:11 2/14/12 11:23 12
2/14/12 11:26 2/14/12 11:41 15
2/14/12 13:00 2/14/12 13:27 27
3/2/12 10:10 3/2/12 10:19 9
3/13/12 19:28 3/13/12 20:13 45
3/13/12 21:54 3/13/12 22:03 9
9/13/12 13:51 9/13/12 16:16 145
9/13/12 20:47 9/13/12 21:22 35
10/18/12 10:26 10/18/12 10:38 12
10/18/12 10:39 10/18/12 11:09 30
10/18/12 13:10 10/18/12 14:58 108
10/18/12 17:41 10/18/12 18:06 25
12/13/12 9:38 12/13/12 9:54 16
12/13/12 11:16 12/13/12 11:34 18
12/13/12 16:44 12/13/12 16:52 8
12/13/12 23:33 12/13/12 23:39 6
12/18/12 15:00 12/18/12 15:11 11
TOTAL 17 events 531 minutes
(8.85 hours)
Year Aggregate GVEA Outage
Time (Hours) 2
2010 1
2011 2
2012 2
2010 – 2012 Average 1.67 hours
CANTWELL OUTAGE RATE AS PERCENTAGE OF GVEA OUTAGE RATE 8.85 / 1.67 = 530%
(1). Data for Cantwell Substation for calendar year 2012. Provided by GVEA.
(2). Data compiled from GVEA Annual Reports for respective years.
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March 2013 – Final Report D‐8
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APPENDIX E – ENVIRONMENTAL CONSIDERATIONS
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E.1 THREATENED AND ENDANGERED SPECIES
The U.S. Fish and Wildlife service and National Marine Fisheries Service were consulted
regarding the proposed project configurations. The project areas do not include any designated
or proposed critical habitat areas for threatened or endangered species.
E.2 FISHERIES AND WILDLIFE
The reservoir associated with a hydro project at Jack River would inundate a significant area
(10s to 100s of acres depending on the specific project configuration). This would have some
impact on wildlife in the project area. Specific impacts would depend on the specific project
configuration and are beyond the scope of this reconnaissance study.
Jack River is not listed as anadromous habitat in the Atlas and Catalog of Waters Important to
the Rearing, Spawning, and Migration of Anadromous Fishes. Resident fish such as sculpin,
white fish, grayling, and likely Dolly Varden occur in the study reach of Jack River. Specific
impacts on resident fish passage would depend on the specific project configuration. The
project would need to mitigate impacts to resident fish. General requirements are described in
Appendix F, Section F.2.2.1.
None of the project configurations are expected to significantly impact anadromous fish
habitat, which starts more than 50 miles downstream of the study area in the Nenana River
near Healy. By regulating flow in Jack River, the project could reduce flow at the upper limit of
anadromous habitat by up to approximately 7%. Peak project operation in late winter could
increase flow at the upper limit of anadromous habitat by approximately 50% from natural flow
conditions. Proper discharge ramping rates and thermal management of water releases would
likely avoid any impacts to anadromous habitat.
E.3 WILD AND SCENIC RIVERS STATUS
Jack River is not a designated Wild and Scenic River (WSR), WSR corridor, or included on the
Nationwide Rivers Inventory.25 Jack River has not been designated for study for future
designation as a WSR or WSR corridor by the U.S. Congress (5(a) study) or by eligible federal
agencies (5(d)(1) study).26 The 2006 East Alaska Proposed Resource Management Plan, which
covers the project area, did not find Jack River eligible for WSR designation. 27
E.4 WATER AND AIR QUALITY
The project would tend to improve air quality by reducing the amount of fossil fuel fired
electricity generation in the railbelt. The type and location of avoided power plant emissions
25 Nationwide Rivers Inventory status checked July 11, 2012. http://www.nps.gov/ncrc/programs/rtca/nri/
26 Personal communications with Cassie Thomas, NPS; Zachary Babb, NPS; and Heath Evans, BLM, July 12, 2012.
27 East Alaska Proposed Resource Management Plan and Environmental Impact Statement, U.S. Department of
Interior, Bureau of Land Management. June 2006.
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March 2013 – Final Report E‐2
would depend on the specific power plants that were offset by Jack River. Based on GVEA’s
fuel costs, the most likely avoided emissions would be from oil‐fired power plants in Fairbanks
and/or North Pole. These avoided emissions would have an incremental beneficial impact on
air quality in the Fairbanks region. In recent years, winter‐time air quality has become very
poor in Fairbanks, frequently violating Federal Clean Air Act standards for PM 2.5 particulates.
EPA fines or sanctions could be imposed starting in 2014 if conditions continue.28 Quantifying
the magnitude of improved air quality in Fairbanks from a Jack River hydro project is beyond
the scope of this study.
Impacts on water quality in Jack River would depend on the specific hydro project
configuration, design, and operational protocols. The reservoir could change oxygen
saturation, suspended sediment levels, sediment transport and deposition characteristics,
temperature, and other water quality parameters in Jack River below the project. Many of
these changes could be controlled through proper design and/or project operational
constraints to avoid or minimize any adverse impacts. Such design or operational constraints
could have a negative impact on the project’s economic feasibility as increased costs or
decreased electrical generation potential.
E.5 WETLAND AND PROTECTED AREAS
A significant fraction of the land to the northeast of Jack River in the project area is a complex
mosaic of wetland and upland areas. Depending on project configuration, some of these
wetlands areas could be crossed by penstocks, access roads, or other project infrastructure.
These impacts can be avoided or minimized by proper routing of these features.
There are also significant wetlands areas located along the bottom of the Jack River valley and
canyon that would be permanently inundated by a project reservoir. These impacts do not
have a practical avoidance or minimization option, and would likely require offsite mitigation. 29
E.6 ARCHAEOLOGICAL AND HISTORICAL RESOURCES
None are known in the project area. Detailed consultations with SHPO or other entities were
not completed as part of this study.
E.7 LAND DEVELOPMENT CONSIDERATIONS
Extension of roads and power lines into the project area could support development of land in
the vicinity of the project.
28 EPA Warns of Consequences of Fairbanks Fails to meet Air Quality Deadline, Fairbanks Daily News‐Miner,
September 28, 2012.
29 Preliminary estimated acreage of wetlands that would be inundated are 65 acres for dam site 3, 110 acres for
dam site 2, and 220 acres for dam site 1.
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report E‐3
The Jack River valley and canyon is an existing snow machine corridor from Cantwell into the
Talkeetna Mountains. Development of dams and reservoirs in the valley would require
alternate routes for snow machine traffic through the project area. Upland areas adjacent to
the reservoir footprints would likely be suitable as alternate snow machine corridors.
Consideration of specific snow machine corridors would depend on the specific hydro project
under consideration.
Depending on the specific project configuration, the project reservoir could be a significant
recreational asset for Cantwell and surrounding areas. The reservoir could be suitable for
motorized or non‐motorized water sports, or stocked for recreational fishing.
Depending on the specific project configuration, a storage hydro project at Jack River could
reduce downstream flood hazards along Jack River, making portions of the existing Jack River
floodplain suitable for development. This would depend on the findings of dam break analyses
risk assessments, and similar studies that would need to be completed for a specific project
configuration.
E.8 TELECOMMUNICATIONS AND AVIATION CONSIDERATIONS
The project will not affect telecommunications or aviation.
E.9 VISUAL AND AESTHETIC RESOURCES
None of the proposed project features would be prominently visible from readily accessible
vantage points such as the Parks Highway, Denali Highway, or Alaska Railroad. All of the
proposed project features would generally be visible from remote alpine vantage points in the
Cantwell area or from the air.
E.10 MITIGATION MEASURES
Wetlands impacts would likely require mitigation. Specific mitigation options have not been
developed at this stage of study.
Depending on the specific development concept, mitigation will likely be required to address
impacts to resident fish passage, and possibly downstream anadromous fish habitat.
Mitigation may also be required for impacts to game habitat inundated by the reservoir.
Native Village of Cantwell
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March 2013 – Final Report E‐4
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
APPENDIX F – PERMITTING INFORMATION
F.1: Federal Permits pages F‐1 to F‐2
F.2: State Permits pages F‐2
F.3: Local Permits pages F‐3
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March 2013 – Final Report
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Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report F‐1
F.1 FEDERAL PERMITS
F.1.1 Federal Energy Regulatory Commission
The Federal Energy Regulatory Commission (FERC) has jurisdiction over hydroelectric projects
that meet certain criteria. Generally, these criteria include:
(1) The project is located on navigable waters,
(2) The project is located on federal land,
(3) The project affects interstate commerce, or
(4) The project is part of an interstate electrical grid.
Projects at dam site 1 with maximum reservoir elevations of approximately 2,615 feet would
partially inundate federal lands (Sections 3 and 10 in T19S R6W, Fairbanks Meridian). This
would trigger FERC jurisdiction by being partially located on Federal land.
Review of land records in the project area indicate there was litigation involving the navigability
of Jack River and other area rivers that was resolved in approximately 2003.30 This litigation
appears to have been related to determining the eligibility of submerged lands for Native
Corporation selection under the Alaska Native Claims Settlement Act (ANCSA). If this litigation
concluded that Jack River is navigable, then any project on Jack River will likely fall under FERC
jurisdiction. Documentation for this litigation was not reviewed as part of this reconnaissance
study, and the navigability status of Jack River, if any was made, is unknown.
The outcome of this litigation would need to be researched and a Declaration of Intention filed
with the FERC in the permitting phase of the project to verify the jurisdictional status of the
project.
If the project enters the permitting phase before project lands are conveyed out of federal
ownership, then the project will fall under FERC jurisdiction per criteria (2) above.
F.1.3 U.S. Army Corps of Engineers (USACE) Permits
The diversion structures, tailraces and other features of the recommended project will be
located within wetlands, therefore a wetlands permit from the USACE will be required.
Depending on the selected project configuration, the project may be eligible for a Nation Wide
Permit #17 for hydro projects. Otherwise, the project will obtain an individual permit.
Additional USACE permits will be required if the study reach of Jack River is considered
navigable.
30 Bureau of Land Management (BLM) Alaska State Office Internal Memorandum 9630 (AK‐925), pertaining to
ANSCA selection F‐14844‐A, dated November 19, 2003.
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Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report F‐2
F.1.4 U.S. Environmental Protection Agency
A stormwater pollution prevention plan will be required for construction of the project.
F.1.5 Federal Aviation Administration
The recommended project will not have any features likely to present a hazard to aviation.
F.2 STATE OF ALASKA PERMITS
F.2.1 Alaska Department of Natural Resources (ADNR) Permits
F.2.1.1 Coastal Zone Consistency Review
The State of Alaska does not currently have a Coastal Zone Management Program. The
previous program, which was terminated June 30, 2011, generally applied to land below 1,000
feet in elevation. The project site is over 2,000 feet in elevation, so was not located within the
state’s coastal zone as defined under the old program.
F.2.1.2 Land Authorizations
Portions of the reservoirs for all project configurations but 3C would submerge some state land.
This would likely require an easement or similar authorization from ADNR.
F.2.1.3 Tidelands Permits
No tidelands permits are needed for the project.
F.2.1.4 Material Sale Agreement
The project would require a significant volume of material for construction of the dam(s).
Material could be sourced from state or native‐owned lands located in the project vicinity.
F.2.1.5 Water Use Permit / Water Rights
The project will need to obtain water rights from the ADNR.
F.2.2 Alaska Department of Fish and Game Permits
F.2.2.1 Fish Habitat Permit
Initial consultations with ADF&G indicate the project reach is likely habitat for resident fish such
as sculpin, grayling, white fish, and possibly resident Dolly Varden. Fisheries surveys would
need to be conducted to determine the presence, abundance, and life stages of fish in Jack
River. This information would guide development of mitigation requirements for the project.
Generally, mitigation would need to comply with the Alaska Fishway Act (AS 16.05.841 to 851),
which requires that the project maintain fish passage around the dam. The Fishway act also
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report F‐3
provides for payment for operation of hatcheries, or a lump sum payment to the ADF&G in lieu
of on‐site mitigation. In practice, the ADF&G prefers to maintain the biological integrity of the
river, and only rarely allows cash payments as mitigation. Specific requirements would depend
on the specific project configuration proposed for development.
F.2.3 Alaska Department of Transportation Permits
Not applicable.
F.2.4 Alaska Department of Environmental Conservation (ADEC) Permits
F.2.4.1 ADEC Wastewater or Potable Water Permits
Not applicable.
F.2.4.2 Solid Waste Disposal Permit
Not applicable.
F.2.4.3 Air Quality Permit & Bulk Fuel Permit
Not applicable.
F.3 LOCAL PERMITS
F.3.1 Borough Permits
All project configurations are located within the Denali Borough. The southern portion of
reservoirs above dam site 1 would be located in the Matanuska‐Susitna Borough (See Figure A‐
3). Both boroughs have local permitting processes that the project would need to follow.
F.3.2 Local City Permits
The community of Cantwell is unincorporated, so no local government permits are required for
the project.
Native Village of Cantwell
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March 2013 – Final Report F‐4
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March 2013 – Final Report
APPENDIX G – ECONOMIC ANALYSIS ASSUMPTIONS
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ECONOMIC ANALYSIS ASSUMPTIONS
The economic analysis of the project configurations considered in this study used a range of
estimated capital costs and related financial parameters to develop a range of estimated energy
costs for each configuration and a range of estimated benefit cost ratios for each configuration.
This appendix explains the ranges used for each parameter.
G.1 ESTIMATED INSTALLED COST
Reconnaissance level cost estimates were developed for each project configuration by
estimating unit quantities and volumes of project components and applying estimated unit
costs to each component line item. The resulting estimated cost was multiplied by a range of
+/‐ 30% to develop a range of probable cost. An approximate 30% contingency was then
applied to the result.
G.2 ESTIMATED ANNUAL PROJECT COSTS
G.2.1 General, Administrative, Operation, Maintenance, Repair, and Replacement Expenses
All operating costs of the projects are assumed to cost between $0.015 and $0.025 per kWh.
This term includes general, administrative, operation, maintenance, repair, and replacement
expenses associated with the project.
G.3 FINANCING
G.3.1 Low‐Cost Debt Financing
Capital project costs are assumed to be financed with $8 million in grants and the balance is
assumed to be a low‐interest loan with a 1.05% interest rate and 30‐year term. A 3% surcharge
is added to the financed amount to cover loan origination fees, underwriting, and guarantee
fees. These loan terms are based on the loan terms for GVEA’s Eva Creek Wind Project, except
the term has been increased from 20 years to 30 years because hydro projects typically have a
longer design life than wind projects.
G.3.2 High‐Cost Debt Financing
The entire project capital cost is assumed to be financed at a 30‐year term at 6% interest. Loan
origination costs of 3% are assumed for items such as application fees, loan guarantee fees, and
other origination fees.
G.3.3 Grants
The ability of the project to obtain grant funds will depend on what state and federal grant
programs exist, whether the project meets specific program eligibility criteria, and whether the
project successfully competes for grant funds.
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March 2013 – Final Report G‐2
The Renewable Energy Fund (REF) Grant Program, used in part to fund this reconnaissance
study, is one of several potential sources of grant funds for this project. Under current program
rules, this project would be eligible for a maximum of $4 million in construction grant funds
from the REF. As an IPP, the NVC would have to agree to certain regulatory and economic
conditions if it accepted construction grant funds under the REF program. These conditions
include a requirement to obtain a CPCN from the RCA, and to be economically regulated by
either the RCA or AEA, limiting the power sales rate for the project to cost‐based rates.
Different conditions may apply depending on the program rules in effect when grant funds are
awarded. Based on available information, these cost‐based rates appear compatible with the
estimated range of power sales rates presented in this study.
G.4 OPERATING MARGINS
Operating margins of 10% of gross revenue and 20% of gross revenue are assumed.
G.5 ESTIMATED POWER SALES RATE
Annualized estimated costs as described above are summed and divided by the estimated total
energy output of the project to calculate an estimated power sales rate for energy from the
project. High and low range estimated annual costs are divided by the same estimated total
energy output.
G.6 ESTIMATED BENEFIT‐COST RATIO
The low‐end of the estimated benefit‐cost ratio range is calculated using the high‐end capital
cost estimate, high end operating costs, high‐end financing scenario, and high‐end operating
margins. Future cash flows are converted to present‐value using a 50‐year life, 30‐year debt
term, zero salvage value at year 50, and 3% discount rate. Project benefits were calculated
using the economic model developed for the Alaska Energy Authority (AEA)’s Renewable Energy
Grant Program Round 6 by the Institute of Social and Economic Research (ISER) at the
University of Alaska Anchorage.
The high‐end of the estimated benefit‐cost ratio range is calculated using the AEA/ISER
economic model. Low‐end capital and operating costs were input to the model.
G.7 ENVIRONMENTAL ATTRIBUTES
No revenue from sale of the project’s environmental attributes is considered in the
reconnaissance study.
G.8 INDIRECT AND NON‐MONETARY BENEFITS
The recommended hydroelectric project offers significant indirect and non‐monetary benefits
in addition to direct economic benefits. These other benefits include:
● Reduced air pollution (NOx, SOx, particulates, and hydrocarbons) due to decreased
operation of the diesel power plants in Fairbanks.
Native Village of Cantwell
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● More stable energy prices. Jack River would incrementally help to stabilize GVEA’s
energy rates.
● The project reservoir may offer new recreational opportunities for the Cantwell area,
including fishing and motorized or non‐motorized water sports.
Native Village of Cantwell
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March 2013 – Final Report G‐4
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March 2013 – Final Report
APPENDIX H – TABULAR HYDROLOGY DATA
Native Village of Cantwell
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October 2011 – Final Report H‐6
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Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
11/2/11 13 87.75 88.20 87.91 87.91 32.97 Gauging Station Installed
11/3/11 48 87.70 88.08 87.77 87.77 32.97 63.5 Flow mmt. by D. Brailey
11/4/11 48 87.86 87.97 87.91 87.76 87.76 32.97 start ice affect
11/5/11 48 87.74 87.93 87.82 87.74 87.74 32.97
11/6/11 48 87.82 88.47 87.92 87.72 87.72 32.96
11/7/11 48 87.68 87.88 87.82 87.71 87.71 32.96
11/8/11 48 87.50 87.72 87.64 87.69 87.69 32.97
11/9/11 48 87.49 88.22 87.90 87.68 87.68 32.96
11/10/11 48 87.75 88.27 88.00 87.66 87.66 32.96
11/11/11 48 87.61 87.75 87.68 87.65 87.65 32.97
11/12/11 48 86.62 87.86 87.59 87.63 87.63 32.98
11/13/11 48 86.77 86.83 86.80 87.61 87.61 33.03
11/14/11 48 86.71 86.84 86.74 87.60 87.60 33.00
11/15/11 48 86.84 87.84 87.29 87.58 87.58 32.95
11/16/11 48 87.84 88.33 88.11 87.57 87.57 32.94
11/17/11 48 88.33 88.65 88.51 87.55 87.55 32.94
11/18/11 48 88.09 88.50 88.31 87.54 87.54 32.95
11/19/11 48 87.80 88.09 87.96 87.52 87.52 32.95
11/20/11 48 87.47 87.80 87.61 87.51 87.51 32.95
11/21/11 48 87.44 87.61 87.50 87.49 87.49 32.96
11/22/11 48 87.42 87.50 87.45 87.47 87.47 32.96 end ice affect
11/23/11 48 87.42 87.48 87.46 87.46 32.95
11/24/11 48 87.47 87.60 87.52 87.52 32.96
11/25/11 48 87.51 87.60 87.55 87.55 32.98
11/26/11 48 87.47 87.54 87.49 87.49 32.94
11/27/11 48 87.46 87.50 87.48 87.48 32.94
11/28/11 48 87.38 87.47 87.43 87.43 32.97
11/29/11 48 87.27 87.38 87.32 87.32 32.97
11/30/11 48 87.27 87.34 87.30 87.30 32.96
12/1/11 48 87.18 87.30 87.23 87.23 32.97
12/2/11 48 87.07 87.18 87.11 87.11 32.98
12/3/11 48 87.02 87.10 87.06 87.06 32.96
12/4/11 48 86.94 87.14 87.04 87.04 32.99
12/5/11 48 87.12 87.27 87.24 87.24 32.95
12/6/11 48 87.17 87.26 87.21 87.21 32.95
12/7/11 48 87.06 87.19 87.13 87.13 32.97
12/8/11 48 86.95 87.06 87.01 87.01 32.97
12/9/11 48 86.87 86.95 86.91 86.91 32.96
12/10/11 48 86.81 86.89 86.87 86.87 32.94
12/11/11 48 86.85 87.04 86.93 86.88 86.88 32.96 start ice affect
12/12/11 48 86.97 87.20 87.12 86.89 86.89 32.94
12/13/11 48 87.20 88.40 87.73 86.90 86.90 32.92
12/14/11 48 88.40 88.71 88.61 86.90 86.90 32.90
12/15/11 48 88.07 88.69 88.52 86.91 86.91 32.91
12/16/11 48 87.33 88.07 87.57 86.92 86.92 32.94
12/17/11 48 87.12 87.33 87.24 86.93 86.93 32.94
12/18/11 48 87.04 87.17 87.09 86.94 86.94 32.94
12/19/11 48 86.98 87.06 87.03 86.94 86.94 32.95
12/20/11 48 86.90 86.99 86.94 86.95 86.95 32.96
12/21/11 48 86.85 86.93 86.89 86.96 86.96 32.94 end ice affect
12/22/11 48 86.87 87.03 86.97 86.97 32.94
12/23/11 48 87.01 87.46 87.14 86.95 86.95 32.93 start ice affect
12/24/11 48 87.46 88.99 88.21 86.94 86.94 32.90
12/25/11 48 88.89 89.17 89.06 86.92 86.92 32.89
March 2013 ‐ Final Report Appendix H ‐ Page H‐1
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
12/26/11 48 89.17 89.44 89.35 86.91 86.91 32.89
12/27/11 48 89.23 89.41 89.29 86.89 86.89 32.89
12/28/11 48 89.07 89.23 89.15 86.88 86.88 32.90
12/29/11 19 89.04 89.09 89.07 86.86 86.86 32.87
12/30/11 5 88.01 89.04 88.74 86.85 86.85 32.90
12/31/11 4 87.97 88.98 88.64 86.83 86.83 32.88
1/1/12 3 87.95 88.90 88.38 86.82 86.82 32.93
1/2/12 2 87.90 88.32 88.05 86.80 86.80 32.95
1/3/12 1 87.67 87.90 87.78 86.79 86.79 32.92
1/4/12 45 87.38 87.67 87.53 86.77 86.77 32.92
1/5/12 48 87.17 87.38 87.27 86.76 86.76 32.93
1/6/12 48 87.04 87.17 87.11 86.74 86.74 32.92
1/7/12 48 86.95 87.04 87.00 86.73 86.73 32.93
1/8/12 48 86.85 86.96 86.90 86.71 86.71 32.92
1/9/12 48 86.78 86.87 86.85 86.70 86.70 32.91
1/10/12 48 86.75 86.85 86.80 86.68 86.68 32.92
1/11/12 48 86.74 86.78 86.76 86.67 86.67 32.92
1/12/12 48 86.72 86.79 86.75 86.65 86.65 32.93
1/13/12 48 86.71 86.74 86.72 86.64 86.64 32.94
1/14/12 48 86.68 86.73 86.71 86.62 86.62 32.92
1/15/12 48 86.63 86.69 86.66 86.60 86.60 32.92
1/16/12 48 86.60 86.63 86.61 86.59 86.59 32.93
1/17/12 48 86.56 86.60 86.58 86.57 86.57 32.94
1/18/12 48 86.54 86.56 86.55 86.56 86.56 32.94
1/19/12 48 86.52 86.54 86.53 86.54 86.54 32.95
1/20/12 48 86.49 86.52 86.51 86.53 86.53 32.93
1/21/12 48 86.50 86.53 86.52 86.51 86.51 32.93 end ice affect
1/22/12 48 86.49 86.51 86.50 86.50 32.92
1/23/12 48 86.48 86.50 86.49 86.49 32.90
1/24/12 3 86.47 86.49 86.48 86.48 32.92
1/25/12 45 86.46 86.47 86.46 86.46 32.92
1/26/12 48 86.45 86.46 86.45 86.45 32.91
1/27/12 48 86.44 86.45 86.44 86.44 32.92
1/28/12 48 86.43 86.44 86.44 86.44 32.92
1/29/12 48 86.43 86.44 86.44 86.44 32.92
1/30/12 48 86.43 86.45 86.44 86.44 32.93
1/31/12 48 86.44 86.45 86.44 86.44 32.92
2/1/12 48 86.42 86.45 86.44 86.44 32.92
2/2/12 48 86.42 86.43 86.43 86.43 32.93
2/3/12 48 86.42 86.44 86.43 86.43 32.92
2/4/12 48 86.41 86.42 86.41 86.41 32.92
2/5/12 48 86.39 86.42 86.41 86.41 32.91
2/6/12 48 86.39 86.42 86.40 86.40 32.92
2/7/12 48 86.39 86.42 86.40 86.40 32.91
2/8/12 48 86.34 86.40 86.38 86.38 32.93
2/9/12 48 86.35 86.39 86.38 86.38 32.93
2/10/12 48 86.36 86.37 86.37 86.37 32.92
2/11/12 48 86.34 86.36 86.35 86.35 32.92
2/12/12 48 86.33 86.36 86.34 86.34 32.94
2/13/12 48 86.32 86.34 86.33 86.33 32.94
2/14/12 48 86.32 86.35 86.34 86.34 32.93
2/15/12 48 86.29 86.34 86.32 86.32 32.91
2/16/12 48 86.29 86.34 86.31 86.31 32.89
2/17/12 48 86.26 86.41 86.31 86.31 32.89
March 2013 ‐ Final Report Appendix H ‐ Page H‐2
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
2/18/12 48 86.41 87.01 86.65 86.31 86.31 32.90 start sensor freeze anomaly
2/19/12 48 87.01 87.95 87.45 86.30 86.30 32.87
2/20/12 48 87.71 89.74 88.61 86.29 86.29 32.83
2/21/12 48 89.34 93.18 91.35 86.29 86.29 32.77
2/22/12 48 93.18 97.65 95.64 86.28 86.28 32.71
2/23/12 48 97.20 99.07 98.24 86.27 86.27 32.68
2/24/12 48 98.11 99.34 98.78 86.27 86.27 32.65
2/25/12 48 96.13 98.11 97.33 86.26 86.26 32.65
2/26/12 48 94.48 96.13 95.17 86.25 86.25 32.63
2/27/12 48 93.52 94.48 94.03 86.25 86.25 32.62
2/28/12 48 92.75 93.60 93.07 86.24 86.24 32.61
2/29/12 48 91.77 92.75 92.25 86.23 86.23 32.59
3/1/12 48 90.89 91.77 91.34 86.23 86.23 32.58
3/2/12 48 90.13 90.89 90.52 86.22 86.22 32.56
3/3/12 48 89.77 92.46 91.18 86.21 86.21 32.54
3/4/12 48 92.19 92.60 92.46 86.21 86.21 32.48
3/5/12 48 91.64 92.19 91.88 86.20 86.20 32.47
3/6/12 48 91.17 91.64 91.39 86.19 86.19 32.45
3/7/12 48 90.72 91.17 90.92 86.19 86.19 32.43
3/8/12 48 90.49 90.72 90.58 86.18 86.18 32.42
3/9/12 48 88.24 90.50 89.80 86.17 86.17 32.40
3/10/12 48 84.70 88.24 86.40 86.17 86.17 32.42
3/11/12 48 82.05 84.70 83.35 86.16 86.16 32.48
3/12/12 48 79.90 82.05 80.90 86.15 86.15 32.54
3/13/12 48 78.10 79.90 78.99 86.15 86.15 32.58
3/14/12 48 77.33 84.05 81.07 86.14 86.14 32.77
PTT failure due to freeze
damage.
3/15/12 48 84.05 84.05 84.05 86.13 86.13 33.20
3/16/12 48 84.05 84.05 84.05 86.13 86.13 33.63
3/17/12 48 84.05 84.05 84.05 86.12 86.12 34.02
3/18/12 48 84.05 84.05 84.05 86.11 86.11 34.44
3/19/12 32 84.05 84.05 84.05 86.11 86.11 34.77
3/20/12 21 84.08 84.09 84.08 86.10 86.10 52.00
3/21/12 48 84.06 84.09 84.09 86.09 86.09 34.07
Air temperature sensor
enabled. New PTT in air.
3/22/12 48 84.06 84.10 84.09 86.09 86.09 36.31
3/23/12 48 84.08 84.09 84.09 86.08 86.08 43.17
3/24/12 48 84.08 84.09 84.09 86.07 86.07 45.88
3/25/12 48 84.08 84.09 84.09 86.07 86.07 45.85
3/26/12 48 84.05 84.22 84.09 86.06 86.06 43.51
3/27/12 48 84.06 87.49 84.77 86.05 86.05 51.43 29.6 Flow mmt. by D. Brailey
3/28/12 48 84.06 84.09 84.07 86.05 86.05 39.78
3/29/12 48 84.06 84.09 84.08 86.04 86.04 31.75
3/30/12 48 84.05 84.12 84.08 86.03 86.03 36.77
3/31/12 48 84.07 84.09 84.08 86.03 86.03 34.94
4/1/12 48 84.06 84.10 84.08 86.02 86.02 41.47
4/2/12 48 84.06 84.09 84.08 86.01 86.01 25.27
4/3/12 48 84.07 84.10 84.08 86.01 86.01 26.78
4/4/12 48 84.06 84.09 84.08 86.00 86.00 26.77
4/5/12 48 84.06 84.09 84.08 85.99 85.99 38.19
4/6/12 48 84.04 84.09 84.08 85.99 85.99 41.29
4/7/12 48 84.05 84.09 84.08 85.98 85.98 38.39
4/8/12 48 84.06 84.09 84.08 85.97 85.97 36.58
4/9/12 48 84.06 84.09 84.08 85.97 85.97 34.37
March 2013 ‐ Final Report Appendix H ‐ Page H‐3
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
4/10/12 48 84.06 84.09 84.08 85.96 85.96 32.94
4/11/12 48 84.06 84.09 84.08 85.95 85.95 37.21
4/12/12 48 84.06 84.09 84.08 85.95 85.95 41.85
4/13/12 48 84.05 84.09 84.08 85.94 85.94 50.59
4/14/12 48 84.06 84.09 84.08 85.93 85.93 46.48
4/15/12 48 84.06 84.10 84.08 85.93 85.93 49.76
4/16/12 48 84.06 84.09 84.08 85.92 85.92 50.35
4/17/12 48 84.06 84.09 84.08 85.91 85.91 47.96
4/18/12 48 84.06 84.09 84.08 85.91 85.91 45.27
4/19/12 48 84.06 84.09 84.08 85.90 85.90 51.90
4/20/12 48 84.05 84.09 84.08 85.89 85.89 49.96
4/21/12 48 84.05 84.09 84.08 85.89 85.89 45.44
4/22/12 48 84.05 84.10 84.08 85.88 85.88 49.00
4/23/12 48 84.06 84.09 84.08 85.87 85.87 46.77
4/24/12 48 84.05 84.09 84.08 85.87 85.87 45.93
4/25/12 48 84.06 84.09 84.08 85.86 85.86 48.72
4/26/12 48 84.06 84.09 84.08 85.85 85.85 48.64
4/27/12 48 84.06 84.09 84.08 85.85 85.85 48.18
4/28/12 48 84.07 84.68 84.27 85.84 85.84 44.17
4/29/12 48 84.07 84.41 84.24 85.83 85.83 49.48
4/30/12 48 84.08 84.24 84.10 85.83 85.83 41.85
5/1/12 48 84.09 84.10 84.09 85.82 85.82 29.49
5/2/12 48 84.08 84.10 84.09 85.81 85.81 34.45
5/3/12 48 84.07 84.10 84.08 85.81 85.81 33.61
5/4/12 48 84.07 84.10 84.09 85.80 85.80 42.33
5/5/12 48 84.08 84.11 84.09 85.79 85.79 44.70
5/6/12 48 84.08 84.10 84.09 85.79 85.79 44.29
5/7/12 48 84.07 84.10 84.09 85.78 85.78 47.96
5/8/12 48 84.08 84.10 84.09 85.77 85.77 45.72
5/9/12 48 84.08 84.10 84.09 85.77 85.77 43.02
5/10/12 48 84.08 84.10 84.09 85.76 85.76 44.04
5/11/12 48 84.07 84.11 84.09 85.75 85.75 43.65
5/12/12 48 84.08 84.10 84.09 85.75 85.75 37.83
5/13/12 48 84.08 84.10 84.09 86.05 86.05 46.21 assumed start of melt
5/14/12 48 84.08 84.11 84.09 86.35 86.35 48.18
5/15/12 48 84.08 84.10 84.09 86.65 86.65 46.17
5/16/12 48 84.08 84.10 84.09 86.95 86.95 50.05
5/17/12 48 84.08 84.10 84.09 87.26 87.26 52.57
5/18/12 48 84.08 84.12 84.09 87.56 87.56 54.64
5/19/12 48 84.08 84.11 84.09 87.86 87.86 53.62
5/20/12 48 84.06 88.19 86.06 88.16 88.16 52.62 end sensor freeze gap
5/21/12 48 88.09 88.32 88.16 88.16 55.87 37.64 PTT deployed into well.
5/22/12 48 88.21 88.40 88.28 88.28 53.91 38.28
5/23/12 48 88.33 88.65 88.42 88.42 55.61 38.31
5/24/12 48 88.62 89.00 88.77 88.77 55.20 38.15
5/25/12 48 88.97 89.60 89.21 89.21 51.45 36.97
5/26/12 48 89.42 89.61 89.51 89.51 50.72 36.74
5/27/12 48 89.54 89.96 89.78 89.78 46.58 36.48
5/28/12 48 89.78 90.00 89.88 89.88 51.48 37.32
5/29/12 48 89.72 90.00 89.84 89.84 49.89 37.40
5/30/12 48 89.53 89.75 89.60 89.60 54.77 38.49
5/31/12 48 89.47 89.63 89.54 89.54 51.31 38.59
6/1/12 48 89.46 89.57 89.52 89.52 45.29 37.74 end rating curve 1
6/2/12 48 89.50 90.24 89.82 89.82 54.26 38.38 est calc flow
March 2013 ‐ Final Report Appendix H ‐ Page H‐4
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
6/3/12 48 90.18 90.37 90.26 90.26 51.71 37.81 est calc flow
6/4/12 48 90.28 90.75 90.40 90.40 54.19 38.72 start rating curve 2
6/5/12 48 90.64 91.39 91.03 91.03 60.89 38.83
6/6/12 48 91.08 91.41 91.22 91.22 50.98 37.76
6/7/12 48 91.05 91.29 91.17 91.17 57.61 38.79
6/8/12 48 91.21 91.60 91.30 91.30 55.31 38.98
6/9/12 48 91.07 91.78 91.46 91.46 50.73 37.58
6/10/12 48 90.81 91.09 90.92 90.92 58.06 37.76
6/11/12 48 90.95 91.14 91.04 91.04 49.38 38.34
6/12/12 48 90.94 91.38 91.17 91.17 43.58 37.84
6/13/12 48 90.80 91.36 91.13 91.13 53.96 37.55
6/14/12 48 90.57 90.94 90.71 90.71 57.05 39.15
6/15/12 48 90.69 90.93 90.79 90.79 54.62 39.77
6/16/12 48 90.62 91.00 90.79 90.79 54.85 39.16
6/17/12 48 90.61 90.93 90.69 90.69 58.78 39.85
6/18/12 48 90.71 91.00 90.86 90.86 58.82 39.88
6/19/12 48 90.84 91.05 90.94 90.94 61.20 40.56
6/20/12 48 90.87 91.12 90.98 90.98 65.25 40.90
6/21/12 48 90.88 91.12 91.00 91.00 63.78 41.61
6/22/12 48 90.85 91.08 90.96 90.96 64.68 41.99
6/23/12 48 90.87 91.02 90.95 90.95 71.04 42.01
6/24/12 48 90.81 91.01 90.90 90.90 66.61 43.03
6/25/12 48 90.70 90.87 90.78 90.78 55.82 42.51
6/26/12 48 90.66 90.77 90.72 90.72 54.49 41.37
6/27/12 48 90.56 90.74 90.64 90.64 52.79 40.42
6/28/12 48 90.50 90.58 90.55 90.55 51.43 40.72
6/29/12 48 90.44 90.53 90.49 90.49 59.55 41.36
6/30/12 48 90.42 90.55 90.48 90.48 57.39 42.81
7/1/12 48 90.42 90.50 90.45 90.45 56.26 43.34
7/2/12 48 90.38 90.48 90.43 90.43 60.47 43.68
7/3/12 48 90.39 90.51 90.46 90.46 51.74 43.99
7/4/12 48 90.30 90.41 90.36 90.36 51.49 42.09
7/5/12 48 90.23 90.32 90.27 90.27 58.03 42.25
7/6/12 48 90.17 90.25 90.21 90.21 62.17 42.85
7/7/12 48 90.18 90.25 90.23 90.23 53.70 44.29
7/8/12 48 90.24 90.35 90.30 90.30 50.55 42.93
7/9/12 48 90.18 90.27 90.22 90.22 55.48 41.59
7/10/12 48 90.14 90.19 90.16 90.16 46.44 42.01
7/11/12 48 90.09 90.17 90.13 90.13 54.98 41.68
7/12/12 48 90.06 90.11 90.09 90.09 50.58 42.65
7/13/12 48 90.04 90.08 90.06 90.06 52.45 42.16
7/14/12 48 90.01 90.05 90.04 90.04 53.02 42.56
7/15/12 48 89.99 90.02 90.01 90.01 50.73 42.65
7/16/12 48 89.97 90.01 89.99 89.99 53.67 42.74
7/17/12 48 89.95 89.99 89.97 89.97 59.84 43.61
7/18/12 48 89.93 89.97 89.95 89.95 59.80 44.11
7/19/12 48 89.92 89.95 89.93 89.93 63.24 45.21
7/20/12 48 89.93 90.13 90.06 90.06 57.67 45.91
7/21/12 48 90.04 90.18 90.10 90.10 52.84 44.56
7/22/12 48 90.17 90.38 90.30 90.30 56.35 44.23
7/23/12 48 90.38 90.61 90.53 90.53 52.37 43.86 600
Partial flow mmt, partial
estimate by J. Groves
7/24/12 48 90.33 90.50 90.41 90.41 56.74 42.62
7/25/12 48 90.24 90.35 90.29 90.29 62.20 43.34
March 2013 ‐ Final Report Appendix H ‐ Page H‐5
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
7/26/12 48 90.17 90.26 90.21 90.21 65.44 44.73
7/27/12 48 90.11 90.19 90.15 90.15 66.61 45.47
7/28/12 48 90.07 90.13 90.10 90.10 63.49 46.04
7/29/12 48 90.05 90.09 90.07 90.07 57.21 46.89
7/30/12 48 90.01 90.06 90.03 90.03 53.31 44.94
7/31/12 48 89.97 90.01 89.99 89.99 58.05 43.91
8/1/12 48 89.95 89.98 89.96 89.96 49.58 44.54
8/2/12 48 89.94 90.02 89.97 89.97 47.94 43.47
8/3/12 48 89.97 90.03 90.00 90.00 48.17 42.63
8/4/12 48 89.96 90.00 89.97 89.97 47.67 42.99
8/5/12 48 89.96 90.01 89.99 89.99 54.95 42.64
8/6/12 48 89.94 89.98 89.96 89.96 56.45 43.06
8/7/12 48 89.90 89.94 89.93 89.93 57.74 43.95
8/8/12 48 89.89 89.92 89.91 89.91 55.66 43.94
8/9/12 48 89.87 89.91 89.89 89.89 62.63 44.11
8/10/12 48 89.89 89.94 89.91 89.91 58.97 45.56
8/11/12 48 89.89 89.92 89.90 89.90 60.04 45.29
8/12/12 48 89.87 89.90 89.88 89.88 65.37 45.73
8/13/12 48 89.85 89.87 89.87 89.87 60.75 45.83
8/14/12 48 89.84 89.87 89.85 89.85 64.15 46.06
8/15/12 48 89.82 89.85 89.84 89.84 58.82 46.30
8/16/12 48 89.82 89.84 89.83 89.83 56.64 46.08
8/17/12 48 89.80 89.83 89.82 89.82 51.82 44.49
8/18/12 48 89.80 89.82 89.81 89.81 50.40 44.29
8/19/12 48 89.81 89.83 89.82 89.82 49.15 43.59
8/20/12 48 89.82 89.94 89.86 89.86 48.01 43.62
8/21/12 48 89.92 89.98 89.95 89.95 57.90 43.42
8/22/12 48 89.88 89.92 89.90 89.90 55.99 42.54
8/23/12 48 89.87 89.89 89.88 89.88 47.18 43.50
8/24/12 48 89.85 89.88 89.87 89.87 47.51 42.80
8/25/12 48 89.85 89.87 89.86 89.86 52.66 42.65
8/26/12 48 89.85 89.96 89.88 89.88 46.36 43.40
8/27/12 48 89.96 90.18 90.11 90.11 48.74 42.37
8/28/12 48 90.04 90.13 90.09 90.09 49.31 41.11
8/29/12 48 90.00 90.05 90.02 90.02 47.98 40.76
8/30/12 48 89.97 90.01 89.99 89.99 51.92 42.00
8/31/12 48 89.98 90.04 90.02 90.02 45.83 42.49
9/1/12 48 90.03 90.07 90.05 90.05 45.15 41.85
9/2/12 48 90.07 90.14 90.11 90.11 45.96 41.65
9/3/12 48 90.13 90.20 90.15 90.15 45.09 41.29
9/4/12 48 90.20 90.32 90.26 90.26 43.78 40.98
9/5/12 48 90.32 90.39 90.36 90.36 40.02 40.07
9/6/12 48 90.35 90.41 90.38 90.38 41.59 39.58
9/7/12 48 90.29 90.37 90.33 90.33 40.60 39.06
9/8/12 48 90.24 90.32 90.28 90.28 41.22 38.59
9/9/12 48 90.18 90.24 90.21 90.21 41.79 38.23
9/10/12 48 90.12 90.20 90.15 90.15 42.53 37.93
9/11/12 48 90.07 90.13 90.10 90.10 41.13 37.39
9/12/12 48 90.03 90.08 90.05 90.05 46.26 37.80
9/13/12 48 89.98 90.04 90.01 90.01 43.72 38.97
9/14/12 48 89.95 89.99 89.97 89.97 40.15 38.66
9/15/12 48 89.95 90.03 89.98 89.98 40.13 38.52
9/16/12 48 90.03 90.41 90.18 90.18 40.27 38.86
9/17/12 48 90.35 90.43 90.39 90.39 39.32 38.24
March 2013 ‐ Final Report Appendix H ‐ Page H‐6
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
9/18/12 48 90.30 90.36 90.33 90.33 37.22 37.39
9/19/12 48 90.28 90.74 90.38 90.38 38.06 37.42
9/20/12 48 90.74 91.75 91.25 91.25 43.28 37.61 End rating curve 2.
9/21/12 48 91.13 92.44 91.80 91.80 51.88 37.67 No rating curve.
9/22/12 48 91.07 91.29 91.18 91.18 57.45 37.93
9/23/12 48 90.77 91.25 90.97 90.97 47.51 37.97
9/24/12 48 90.18 90.77 90.47 90.47 39.87 38.36
9/25/12 48 89.76 90.18 89.96 89.96 47.57 38.58
9/26/12 48 89.48 89.76 89.60 89.60 46.74 38.30
9/27/12 48 89.27 89.48 89.37 89.37 44.50 38.06
9/28/12 48 89.14 89.27 89.20 89.20 40.46 37.87
9/29/12 48 88.99 89.14 89.06 89.06 33.98 37.69
9/30/12 48 88.89 88.99 88.92 88.92 34.29 37.47
10/1/12 48 88.77 89.00 88.89 88.89 29.47 36.81
10/2/12 48 88.74 88.90 88.81 88.81 33.86 35.75
10/3/12 48 88.67 88.79 88.71 88.71 37.55 34.82
10/4/12 48 88.70 88.80 88.75 88.75 40.90 34.74
10/5/12 48 88.67 88.85 88.72 88.72 41.64 35.25
10/6/12 48 88.67 88.74 88.71 88.71 37.84 36.11
10/7/12 48 88.58 88.69 88.61 88.61 37.91 36.74
10/8/12 48 88.55 88.58 88.57 88.57 38.52 36.88
10/9/12 48 88.49 88.55 88.52 88.52 37.73 36.90
10/10/12 48 88.43 88.49 88.46 88.46 31.79 36.88
10/11/12 48 88.43 88.61 88.54 88.54 26.72 36.43
10/12/12 48 88.41 88.54 88.46 88.46 22.72 35.25
10/13/12 48 88.30 88.45 88.36 88.36 20.37 33.86
10/14/12 48 88.33 88.64 88.42 88.42 26.15 32.83
10/15/12 48 88.32 88.58 88.43 88.43 21.50 32.31
10/16/12 48 88.30 88.48 88.41 88.41 19.11 32.11
10/17/12 48 88.24 88.48 88.35 88.35 21.68 31.92
10/18/12 48 88.14 88.37 88.23 88.23 19.89 31.78
10/19/12 48 88.13 88.34 88.20 88.20 22.20 31.67
10/20/12 48 88.10 88.23 88.16 88.16 20.53 31.61
10/21/12 48 88.09 88.30 88.19 88.19 9.06 31.59
10/22/12 48 88.18 88.29 88.22 88.22 8.95 31.58 Start suspected ice affect.
10/23/12 48 88.22 88.50 88.37 88.37 2.98 31.56
10/24/12 48 88.47 88.87 88.67 88.67 4.82 31.54
10/25/12 48 88.67 88.96 88.83 88.83 11.76 31.50
10/26/12 48 88.54 88.76 88.65 88.65 15.60 31.50
10/27/12 48 88.38 88.59 88.45 88.45 13.56 31.56
10/28/12 48 88.34 88.45 88.41 88.41 19.36 31.57
10/29/12 48 88.24 88.37 88.31 88.31 18.41 31.54 End suspected ice affect.
10/30/12 48 88.08 88.29 88.16 88.16 15.96 31.55
Subsequent records not
reviewed for suspected ice
affect.
10/31/12 48 88.27 88.91 88.69 88.69 11.80 31.52
11/1/12 48 88.90 89.51 89.23 89.23 0.82 31.46
11/2/12 48 89.51 89.83 89.72 89.72 6.09 31.41
11/3/12 48 89.40 89.62 89.49 89.49 10.35 31.40
11/4/12 48 89.58 89.92 89.71 89.71 8.03 31.38
11/5/12 48 89.92 90.46 90.17 90.17 5.09 31.37
11/6/12 48 90.34 90.72 90.54 90.54 -1.69 31.36
11/7/12 48 90.72 90.99 90.84 90.84 -3.05 31.35
11/8/12 48 90.93 91.30 91.15 91.15 3.67 31.33
March 2013 ‐ Final Report Appendix H ‐ Page H‐7
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
11/9/12 48 91.15 91.32 91.27 91.27 17.85 31.32
11/10/12 48 90.93 91.15 91.03 91.03 25.89 31.33
11/11/12 48 90.71 90.96 90.81 90.81 20.23 31.33
11/12/12 48 90.67 90.80 90.73 90.73 1.47 31.34
11/13/12 48 90.44 90.70 90.58 90.58 3.87 31.34
11/14/12 48 90.59 90.86 90.73 90.73 17.30 31.32
11/15/12 48 90.43 90.79 90.61 90.61 11.22 31.32
11/16/12 48 90.06 90.43 90.27 90.27 4.81 31.32
11/17/12 48 90.03 90.13 90.08 90.08 -11.35 31.33
11/18/12 48 90.01 90.13 90.07 90.07 -11.52 31.31
11/19/12 48 90.01 90.03 90.02 90.02 -16.51 31.28
11/20/12 48 89.90 90.02 89.97 89.97 -15.79 31.29
11/21/12 48 89.64 89.95 89.80 89.80 -17.64 31.28
11/22/12 48 89.23 89.64 89.43 89.43 -11.46 31.29
11/23/12 48 89.07 89.23 89.14 89.14 -10.39 31.29
11/24/12 48 88.88 89.10 89.05 89.05 -8.37 31.30
11/25/12 48 88.94 89.16 89.04 89.04 -7.76 31.28
11/26/12 48 88.76 88.94 88.86 88.86 -5.01 31.29
11/27/12 48 88.51 88.76 88.65 88.65 -6.67 31.29
11/28/12 48 88.43 88.54 88.51 88.51 -13.67 31.29
11/29/12 48 88.17 88.48 88.34 88.34 -1.40 31.31
11/30/12 48 88.04 88.18 88.11 88.11 -12.77 31.31
12/1/12 48 87.91 88.04 87.96 87.96 -15.99 31.32
12/2/12 48 87.78 87.92 87.85 87.85 0.81 31.33
12/3/12 48 87.68 87.90 87.77 87.77 -9.07 31.33
12/4/12 48 87.64 87.79 87.71 87.71 -26.14 31.32
12/5/12 48 87.43 87.64 87.54 87.54 -19.58 31.34
12/6/12 48 87.36 87.43 87.38 87.38 -16.97 31.35
12/7/12 48 87.38 87.42 87.40 87.40 -13.74 31.35
12/8/12 48 87.23 87.38 87.30 87.30 -3.22 31.35
12/9/12 48 87.22 87.24 87.23 87.23 13.56 31.34
12/10/12 48 87.21 87.22 87.22 87.22 18.42 31.34
12/11/12 48 87.22 87.24 87.23 87.23 15.95 31.34
12/12/12 48 87.24 87.24 87.24 87.24 18.62 31.33
12/13/12 48 87.23 87.27 87.25 87.25 16.89 31.33
12/14/12 48 87.21 87.26 87.24 87.24 -0.05 31.33
12/15/12 48 87.10 87.22 87.16 87.16 -6.21 31.34
12/16/12 48 87.07 87.11 87.08 87.08 -0.01 31.31
12/17/12 48 87.01 87.07 87.04 87.04 -18.57 31.31
12/18/12 48 86.98 87.03 87.00 87.00 -12.42 31.32
12/19/12 48 86.94 86.98 86.96 86.96 -3.37 31.32
12/20/12 48 86.91 86.97 86.93 86.93 -1.55 31.34
12/21/12 48 86.88 86.91 86.89 86.89 -22.51 31.29
12/22/12 48 86.83 86.88 86.86 86.86 -18.65 31.30
12/23/12 48 86.81 86.84 86.83 86.83 -15.10 31.31
12/24/12 48 86.81 86.85 86.83 86.83 -5.01 31.31
12/25/12 48 86.79 86.82 86.81 86.81 19.01 31.31
12/26/12 48 86.80 86.81 86.81 86.81 20.91 31.29
12/27/12 48 86.77 86.80 86.79 86.79 21.06 31.30
12/28/12 48 86.73 86.77 86.75 86.75 18.05 31.31
12/29/12 48 86.73 87.11 86.90 86.90 29.81 31.31
12/30/12 48 86.78 86.93 86.84 86.84 37.06 31.30
12/31/12 48 86.70 86.78 86.74 86.74 27.68 31.32
1/1/13 48 86.67 86.70 86.69 86.69 33.51 31.30
March 2013 ‐ Final Report Appendix H ‐ Page H‐8
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
1/2/13 48 86.63 86.70 86.66 86.66 23.76 31.30
1/3/13 48 86.57 86.63 86.60 86.60 26.61 31.31
1/4/13 48 86.55 86.58 86.56 86.56 19.20 31.32
1/5/13 48 86.53 86.55 86.54 86.54 22.85 31.32
1/6/13 48 86.51 86.53 86.52 86.52 23.75 31.33
1/7/13 48 86.47 86.51 86.49 86.49 16.23 31.33
1/8/13 48 86.43 86.47 86.44 86.44 -0.32 31.29
1/9/13 48 86.40 86.43 86.41 86.41 2.28 31.31
1/10/13 48 86.42 86.51 86.45 86.45 14.31 31.31
1/11/13 48 86.46 86.51 86.48 86.48 18.39 31.32
1/12/13 48 86.43 86.47 86.44 86.44 25.16 31.29
1/13/13 48 86.42 86.44 86.43 86.43 31.94 31.30
1/14/13 48 86.41 86.45 86.43 86.43 32.75 31.30
1/15/13 48 86.41 86.46 86.44 86.44 14.92 31.30
1/16/13 48 86.38 86.55 86.44 86.44 8.72 31.31
1/17/13 48 86.33 86.55 86.43 86.43 5.66 31.31
1/18/13 48 86.33 86.62 86.47 86.47 -3.40 31.31
1/19/13 48 86.44 86.73 86.57 86.57 9.78 31.32
1/20/13 48 86.56 86.73 86.65 86.65 17.88 31.31
1/21/13 48 86.42 86.56 86.47 86.47 13.88 31.31
1/22/13 48 86.38 86.53 86.43 86.43 12.51 31.32
1/23/13 48 86.37 86.47 86.42 86.42 10.57 31.31
1/24/13 48 86.35 86.44 86.38 86.38 7.36 31.33
1/25/13 48 86.24 86.37 86.28 86.28 -6.67 31.32
1/26/13 48 86.27 86.40 86.33 86.33 -13.12 31.34
1/27/13 48 86.34 86.45 86.39 86.39 -14.70 31.32
1/28/13 48 86.27 86.34 86.29 86.29 -21.87 31.35
1/29/13 48 86.22 86.31 86.28 86.28 -2.90 31.34
1/30/13 48 86.25 86.30 86.27 86.27 11.00 31.33
1/31/13 48 86.21 86.25 86.23 86.23 25.63 31.32
2/1/13 48 86.16 86.21 86.19 86.19 19.68 31.32
2/2/13 48 86.15 86.31 86.22 86.22 24.80 31.33
2/3/13 48 86.19 86.40 86.25 86.25 29.04 31.32
2/4/13 48 86.24 86.34 86.29 86.29 26.34 31.34
2/5/13 48 86.22 86.34 86.26 86.26 23.51 31.32
2/6/13 48 86.18 86.30 86.22 86.22 10.05 31.31
2/7/13 48 86.16 86.23 86.20 86.20 11.57 31.31
2/8/13 48 86.12 86.44 86.22 86.22 22.14 31.31
2/9/13 48 86.30 86.42 86.35 86.35 27.42 31.32
2/10/13 48 86.22 86.34 86.28 86.28 29.47 31.30
2/11/13 48 86.15 86.22 86.19 86.19 22.63 31.30
2/12/13 48 86.11 86.16 86.14 86.14 15.37 31.31
2/13/13 48 86.08 86.14 86.10 86.10 22.27 31.32
2/14/13 48 86.07 86.12 86.09 86.09 26.06 31.33
2/15/13 48 86.03 86.08 86.07 86.07 18.62 31.32
2/16/13 48 86.00 86.13 86.05 86.05 5.76 31.29
2/17/13 48 86.00 86.19 86.08 86.08 8.08 31.29
2/18/13 48 85.95 86.08 86.00 86.00 -0.59 31.31
2/19/13 48 86.07 86.26 86.15 86.15 -9.20 31.31
2/20/13 48 86.21 86.28 86.25 86.25 4.35 31.28
2/21/13 48 86.10 86.21 86.14 86.14 5.26 31.31
2/22/13 48 86.03 86.10 86.06 86.06 9.68 31.29
2/23/13 48 85.98 86.03 86.00 86.00 16.57 31.30
2/24/13 48 85.95 85.98 85.97 85.97 21.01 31.31
March 2013 ‐ Final Report Appendix H ‐ Page H‐9
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study
Polarconsult Alaska, Inc.
Recorded Stage, (ft, station datum) Temperature Data
Date Record
Count
Daily
Min.
Daily
Max.
Daily
Mean
Corrections
to Daily
Mean
Corrected
Daily Mean
Air, Mean
Daily (F)
Water,
Mean
Daily (F)
Measured
Flow Notes
2/25/13 48 85.90 85.96 85.94 85.94 21.48 31.32
2/26/13 48 85.90 85.93 85.92 85.92 13.60 31.32
2/27/13 48 85.87 85.91 85.89 85.89 17.28 31.33
2/28/13 48 85.87 85.90 85.88 85.88 22.95 31.33
3/1/13 48 85.85 85.90 85.87 85.87 24.47 31.34
3/2/13 48 85.85 85.88 85.87 85.87 23.01 31.33
3/3/13 48 85.82 85.92 85.86 85.86 17.20 31.31
3/4/13 48 85.84 85.89 85.86 85.86 19.48 31.31
3/5/13 48 85.82 85.85 85.83 85.83 19.42 31.29
3/6/13 48 85.78 85.84 85.81 85.81 20.39 31.30
3/7/13 46 85.80 86.13 85.99 85.99 26.92 31.32
download for final recon.
study report. Station still in
working order.
March 2013 ‐ Final Report Appendix H ‐ Page H‐10
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
APPENDIX I – DRAFT REPORT REVIEW COMMENTS AND RESPONSES
Native Village of Cantwell
Jack River Hydroelectric Reconnaissance Study Polarconsult Alaska, Inc.
March 2013 – Final Report
This page intentionally blank.
polarconsult alaska, inc.
1503 West 33rd Avenue, Suite 310
Anchorage, Alaska 99503-3638
Phone: (907) 258-2420
FAX: (907) 258-2419
M EMORANDUM
130311-JACKRREPORT_AEACOMMENTS.DOC
DATE: March 11, 2013
TO: Gordon Carlson, Project Manager, Native Village of Cantwell
FROM: Joel Groves, Project Manager, Polarconsult
SUBJECT: Response to AEA Review Comments on Jack River Hydroelectric Study and
Summary of Other Major Revisions to Final Report
CC: Final Report Appendix I
The Client Review Draft of the Jack River Hydroelectric Reconnaissance Study Final Report was
provided to the Alaska Energy Authority (AEA) on November 28, 2012. The AEA provided
comments on January 7, 2013.
AEA comments and Polarconsult responses are summarized below. As appropriate, AEA’s
comments have been incorporated into the final release of the Jack River Hydroelectric
Reconnaissance Study Final Report, dated March 2013.
AEA Comments Received (Polarconsult responses in BLUE)
1. Page iii: All the schemes considered in the recon study are for storage projects which will
impact resident fish movement through the construction of dams ranging from 40 to 250 feet in
height. The consultant needs to have a general conversation with ADF&G to assess whether
such a project (100‐200 feet high dam) could be permitted by ADF&G without an upstream fish
passage system implemented.
Polarconsult contacted Bill Morris of the Fairbanks ADF&G field office to generally discuss
ADF&G mitigation requirements for the project configurations considered. ADF&G would
first require baseline fisheries surveys to characterize the existing resident fish populations in
the affected reach of Jack River. Mitigation measures would then depend on the results of
the surveys. Generally, AS 16.05.841 ‐ 51 requires that the project either provide for fish
passage or provide monetary mitigation by funding hatchery operations or lump sum
payment to ADF&G. In practice, ADF&G attempts to maintain the biological function of the
river and only rarely resorts to payments in‐lieu of on‐site mitigation. The report narratives
have been revised to include a more detailed discussion of this matter.
2. The proposed hydro sites are in major snow machine corridors of travel and would have
impacts to that use during winter drawdown.
Continued snow machine access to areas upstream of the project can be accommodated by
routing traffic along corridors that are outside of the reservoir inundation zone. Specific
routes would depend on the hydro project configuration that is selected for development.
Section E.7 in Appendix E has been revised to include a discussion of this topic.
P OLARCONSULT M EMORANDUM
March 11, 2013 Page 2 of 7
3. Provide all field data collected from Jack River flows in appendix of the report, including
river stage data from the data logger located in the Jack River well casing installed for this
study.
Jack River flow measurements are documented in Appendix C of the Draft Report, and stage
data from the well casing data logger at RM 11.34 are documented in Appendix I of the Draft
Report. These sections are also provided in the Final Report, with data from November 2012
to March 2013 appended to the tables and figures as appropriate.
4. Given the high degree of active stream channel moving around in the wide flood channel of
Jack River, the amount of erodible and weathered material lying on the banks/cliffs of the
proposed reservoirs for the three proposed dam sites and the associated potential for
significant debris load movement during high flow events, it would appear any impoundment
being considered would be at risk for a short life due to infill from sediment transport and
capture. Please comment on this and attempt a high level analysis of the issue.
Reservoir sedimentation is estimated to reduce annual energy output of project
configurations 1A and 1B by 88% once equilibrium sedimentation is reached in 270 to 460
years. The reservoirs of other project configurations are estimated to reach equilibrium
sedimentation more quickly (10 to 240 years), but sedimentation is estimated to decrease
annual energy output by only 94 to 98% for these configurations. Reservoir sedimentation is
not expected to effect the economics of any project configurations as presented in this study.
A narrative discussing reservoir sedimentation and providing initial estimates of probable
reservoir life has been added to Appendix D, section D.3. and referenced in the main
narrative of the report.
5. 3.1: Says to see Figure A‐3 to find Windy Creek and Cantwell Creek tributaries. Could not
make these out on Figure A‐3. If possible, Figure A‐3 can be fixed to be made more clear.
Text labels for Windy Creek and Cantwell Creek have been added to Figure A‐3.
6. The basis for a Jack River project is to provide backup should the AIS experience an outage.
Section 3.2.3 mentions past blackouts being caused by avalanches, lightning strikes. On average
how long do these blackouts last? And how often?
Reducing the outage rate in Cantwell is one benefit of the project, but is not the project’s sole
basis. Other potential benefits are discussed in paragraph two of Section 3.3 of the report,
and include providing long‐term rate relief from GVEA’s increasing electric rates, possible
flood protection by using the project reservoir for flood control, and a potential revenue
source for the Native Village of Cantwell.
GVEA outage data at the Cantwell Substation for 2012 indicates that outage rates in the
Cantwell service area are about 5.3 times higher than for the GVEA system at‐large. This does
not include outages due to problems on the local distribution system, so actual outage rates
in Cantwell and nearby communities are somewhat higher. A discussion of outages and
P OLARCONSULT M EMORANDUM
March 11, 2013 Page 3 of 7
outage data has been added to Appendix D, section D.4, and referenced in the main narrative
of the report.
7. Figure A‐3: Difficult to see what arrows are pointing at, especially with outlines of basins all
the same color. Perhaps different colors or line types with a legend would be more clear.
Figure A‐3 has been revised to enhance clarity of the information presented.
8. Page 20 and Page G‐1: All the economic analyses performed for the various options for Jack
River include an $8 M grant, (presumably from AEA’s REF Grant program). Accepting a REF
grant for construction funding requires the grant recipient to become a CPCN regulated by the
RCA. Adjust your narrative so it is consistent with your table information.
The source of grant funding for this project is not limited to the Renewable Energy Fund (REF)
Grant Program. The ability of the project to obtain grant funds will depend on what state and
federal grant programs exist, whether the project meets specific program eligibility criteria,
and whether the project successfully competes for those grant funds, if and when the project
is ready to pursue construction funding. If the Native Village of Cantwell diligently advances
the project, this would not occur until 2016 or 2017.
The narrative in Appendix G, Section G.3 has been expanded to clarify the regulatory and
contractual conditions associated with construction grants to IPPs from the REF Grant
Program. Also, the narrative has been revised to clarify that renewable energy projects
located on the railbelt are only eligible for $4 million in construction grant funding under
current REF program rules.
9. Page 22: Section 4.1.2 – If NVC were to form an independent electric utility, they would also
be responsible to maintain all distribution, metering, billing and other non‐generation related
services of a bonafide utility. This needs to be highlighted in your narrative discussion since it
may not be readily discernible to the lay reader.
The narrative in Section 4.1.2 has been revised to emphasize these and other responsibilities
of a full‐service electric utility.
10. Page 25: Table 4‐1. The Susitna Watana hydro project is expected to come on line in 2024
(not 2022).
Table 4‐1 has been revised to reflect information on the Susitna‐Watana Hydro Project as
presented to the AEA Board of Directors on January 10, 2013.
11. There are two Table 4‐1s.
Table numbering has been corrected.
12. Figure A‐2: There are several portions of unconnected red lines indicating GVEA service
territory boundaries on this map. Verify the boundaries and edit the map as needed.
P OLARCONSULT M EMORANDUM
March 11, 2013 Page 4 of 7
The GVEA service area in the project vicinity includes Township 18 South, Range 7 West.
Areas south and east of this are outside the GVEA service area. The lighter red lines on Figure
A‐2 were associated with land status boundaries. Figure A‐2 has been revised to correct this
ambiguity.
13. Report states projects ranging in installed capacity from 1.4‐7.3 MW appear technically
viable – which arrangement is the 1.4 MW project? (Table 3‐3 does not show a 1.4 project)
References to a 1.4 MW project are typographic errors and are meant to read 1.7 MW. Also,
the installed capacities shown in Table 3‐3 for project configurations 3A, 3B, 3C were
incorrect. All other information on Table 3‐3 was reviewed and these were the only errors.
All instances of “1.4 MW” in the report tables and narrative were corrected to “1.7 MW”.
The narrative and related tables were also reviewed for related errors and none were found.
14. Tailrace with 150 cfs of flow will greatly affect and alter the pond habitat for Option 1A.
Don’t know if this is a viable option.
This is a valid question for this particular project configuration that is beyond the scope of a
reconnaissance study. The narrative at Section 3.5.8 has been revised to discuss this matter
in more detail.
15. B‐2: Caption for Photo B‐4 may be incorrect.
The caption for Photograph B‐4 has been corrected.
16. Appears the channel where the stream gage is located is continually shifting causing
discharge curves to be questionable at best for unknown periods of time until measurements
are taken again. Usually gages are placed in portions of streams that are fairly stable, please
comment on the rationale for placing the stream gage at that location and if it is the best
location should the project be advanced.
Three general gauging station sites appropriate for this study were considered along Jack
River. These sites, and the reason the RM 11.34 site was selected, are discussed below.
1. In the canyon in the vicinity of RM 15. There are exposed rock outcrops and well‐confined
stream corridors that are likely to be more stable than the selected gauging station at RM
11.34. This would be a relatively remote installation that would be very difficult to access
for installation, flow measurements, or station maintenance. This site would most likely
not have cellular or satellite coverage due to the steep canyon terrain, requiring on‐site
data storage and introducing the risk of data loss in the event the station hardware was
destroyed in a flood or landslide. Consideration of these factors in concert with the
limited funds available for this study precluded use of this site.
2. The selected gauging station. The site at RM 11.34 is immediately downstream of the
canyon outlet, and is believed to accurately characterize surface flow in Jack River at the
prospective dam sites. The site is readily accessible, and has cellular coverage for a
telemetered installation. Active meandering of Jack River was a known risk with this site
P OLARCONSULT M EMORANDUM
March 11, 2013 Page 5 of 7
(hence the decision to house the installation in a steel well casing), and proved to be
worse than anticipated for the 2011‐12 gauging campaign.
3. Gauging stations at either the Parks Highway Bridge (RM 9.51) or the Denali Highway
Bridge (RM 7.21). Both sites would be readily accessible and would have cellular
coverage. The primary limitation of these sites is that Jack River traverses two to four
miles of alluvial plain between RM 11.5 (Dam Site #3) and these sites. A significant
fraction of the surface flow at RM 11.5 may percolate into the alluvial substrate upstream
of RM 9.51 and 7.21, resulting in a potentially significant underestimate of the flow
available for hydropower generation. This concern led to exclusion of these sites for this
study.
Based on experience from the 2011‐12 stream gauging campaign, future stream gauging
efforts should continue the use of the RM 11.34 site, but budget for frequent flow
measurements through the summer season to recharacterize the site after channel shifting
events. An alternate approach would be to install a new gauging station at one of the two
downstream bridge sites, and conduct a series of concurrent flow measurements to quantify
differential flow between the downstream gauging station and the prospective dam site(s).
The hardware at the RM 11.34 gauging station remains in working order and can be moved to
a new station location.
A narrative discussing the issues with the existing gauging station and recommended
strategies for future gauging efforts at Jack River has been added to Appendix C as Section
C.2.5.
17. Appendix E: There are two subsections listed as E.3.
Section numbering in Appendix E has been corrected.
18. Some project schemes call for two 60‐inch penstocks. Wouldn’t it be less costly to use a
single, larger penstock?
The reconnaissance‐level analysis of penstock costs indicated that the installed cost of
multiple 60‐inch penstocks may be less than that of a hydraulically‐equivalent larger‐
diameter penstock. This is principally due to increased cost of shipping. Two sections of 60‐
inch pipe generally fit on a single flat‐bed trailer, compared with only one section typically
permitted for larger diameter pipe. This approximately doubles the per‐foot shipping cost for
larger diameter pipe. Also, providing a separate penstock for each turbine‐generator unit
provides greater operational redundancy and reliability, which may be desirable for the
larger project configurations considered. This issue would be addressed in the design stage of
the selected project configuration. This point has been clarified in the report narrative at
Section 3.5.6.
19. B/C ratios for the various projects range between 0.5‐3.0. B/C ratio of 0.5 for a hydro
project is rather low and normally would not be recommended however we understand the
ranges stem from reconnaissance‐level work.
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March 11, 2013 Page 6 of 7
The wide range of B/C ratios are a direct result of the quality of data available to perform the
reconnaissance‐level analyses for this study. Site geology is not well characterized, and
would significantly affect the cost and feasibility of various dam configurations. Potential
environmental constraints on the project operating regime, the cost and nature of
environmental mitigation requirements, and the resource hydrology are additional factors
that contribute to the to range of B/C ratios.
20. Wholesale purchase of electrical output from a Jack River project by GVEA appears to be
the most accessible market. Based on other alternative energy projects GVEA purchases from
(Delta Wind Farm) GVEA would only purchase power at the average avoided energy cost, which
may be in the range of $0.11‐ $0.13/kWh. Based on this and the estimated cost for the
alternative projects, only if the recommended projects can be built within the “low‐end”
estimates would a Jack River project be feasible.
This is correct. None of the project configurations considered in this study are economic at
GVEA’s current system average avoided energy costs using the ‘average’ cost estimates.
Other assumptions for costs and purchase rates do indicate that some of the project
configurations at Jack River are economically viable. This point has been clarified in the
report narratives.
P OLARCONSULT M EMORANDUM
March 11, 2013 Page 7 of 7
OTHER SIGNIFICANT REVISIONS FROM DRAFT REPORT
1. The executive summary, Section 1.1, and Section 5.0 narratives were revised to more clearly
explain the high‐level objectives of a reconnaissance study, and the inherent limitations of the
findings described in the reconnaissance study report.
2. Table 3‐3 was revised to add a row with the estimated inactive reservoir volume for each
project configuration.
3. Table 4‐1 was updated to reflect new estimates on delivered energy costs for LNG trucked
from the North Slope to Fairbanks and for the Susitna‐Watana Hydroelectric Project.
4. The narrative in Section F.1.1 was amended to clarify that until project lands selected by
Ahtna, Inc. or the Native Village of Cantwell are patented out of Federal ownership, a hydro
project occupying these lands may fall under FERC jurisdiction, regardless of other jurisdictional
criteria.