HomeMy WebLinkAboutNuyakuk River Hydro Study Plan - Aug 2022 - REF Grant 7013001Solutions for the Future
Solutions for the Future
REVISED STUDY PLAN
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
August 2022
TABLE OF CONTENTS
Appendices
LIST OF FIGURES
LIST OF TABLES
ACRONYMS AND ABBREVIATIONS
1.0 INTRODUCTION
Table 1-1. Nuyakuk Project Aquatics Resources Work Group (ARWG) meeting dates and general
topics discussed.
Date Meeting Description
1.1 Revised Study Plan Overview
1.2 Comments on the Revised Study Plan
1.3 Proposed Study Plan Meetings
1.4 Public Meetings
1.5 FERC Process Plan and Schedule
Table 1-2. Integrated Licensing Process (ILP) milestones for the Nuyakuk River Hydroelectric
Project (FERC 2022).
Pre-Filing Milestone Responsible
Party
Date and Location (if applicable)
[Required FERC ILP Timeframe]
Pre-Filing Milestone Responsible
Party
Date and Location (if applicable)
[Required FERC ILP Timeframe]
2.0 PROJECT LOCATION AND DESCRIPTION
2.1 Project Location
2.2 Project Lands
Table 2-1. Land ownership within the proposed Project boundary.
Owner/Agency Acreage
Total proposed Project lands 2,860.60
Figure 2-1. Proposed Project location.
Figure 2-2. Proposed Project boundary.
Figure 2-3. Project conceptual plan.
2.3 Project Facilities
Figure 2-4. Nuyakuk Falls, looking upriver toward Tikchik Lake. The proposed Project location is
on the peninsula on the left side of the photograph.
Figure 2-5. Nuyakuk Falls, looking across the Nuyakuk River to the proposed Project location.
2.3.1 Summary of Project Features
Table 2-2. Summary of proposed Project features.
SUMMARY OF PROJECT FEATURES
Number of Generating Units
Turbine Type
Rated Generator Output
Maximum Rated Turbine Discharge
Diversion Forebay Water Surface Elevation
Turbine Centerline Elevation (Preliminary)
Normal Tailwater Elevation
Average Annual Energy
Gross Head
Net Head at Maximum Rated Discharge
Watershed Characteristics
Nuyakuk River Diversion
Water Conveyance
Powerhouse
Tailrace
Transmission Line
Access Roads
2.3.2 Nuyakuk Falls Diversion & Intake
2.3.3 Conveyance Tunnels to Powerhouse
2.3.4 Bifurcation to Turbine Units
2.3.5 Powerhouse
2.3.6 Tailrace
2.3.7 Switchyard / Transmission Line/Switchyard
2.3.8 Proposed Construction and Development Schedule
2.4 Project Operation
2.4.1 Proposed Project Operations
Figure 2-6. Mean daily discharge at USGS Gage No. 1530200 from October 1, 1986 – September 30,
2019.
Figure 2-7. Estimated average monthly power generation for the proposed Project.
2.4.2 Project Capacity and Production
3.0 STUDY REQUESTS RECEIVED AND RESPONSES
Table 3-1. Study requests received and corresponding study plans.
4.0 PROPOSED STUDIES
4.1 Aquatics/Fisheries Resources
Figure 4-1. Simple salmon life cycle and potential Project impacts. A similar conceptual approach
may be applicable to resident species. Time and periodicity are implicit.
4.1.1 Characterization of the Fish Community and Behavior Near the Project Area
4.1.1.1 General Description of Proposed Study
4.1.1.2 Geographic Scope
Figure 4-2. Proposed characterization of the fish community and behavior near the Project area study Zones 1-3, Nuyakuk River, Alaska (FERC No. 14873).
4.1.1.3 Study Goals and Objectives
4.1.1.4 Relevant Resource Management Goals
4.1.1.5 Existing Information and Need for Additional Information
4.1.1.6 Project Nexus
4.1.1.7 Methodology
Literature Review
Table 4-1. Preliminary life-stage periodicity for a sample of the fish species utilizing the Nuyakuk
River, Alaska. Subject to revision.
Species1 Life Stage Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Candidate Fish Sampling Methods
1. Fish Community
Figure 4-3. Candidate sampling locations within zones 1 and 3 for characterizing fish community and behavior near the Project area.
2. Upstream Adult Salmon Migration
3. Downstream Juvenile Salmon Migration
4. Timing, distribution and relative abundance of Piscivores
4.1.1.8 Proposed Deliverables and Schedule
4.1.1.9 Level of Effort and Cost
4.1.2 Nuyakuk Falls
2 Fish Passage Study
4.1.2.1 General Description of Proposed Study
Figure 4-4. Daily hydrograph of the Nuyakuk River with (regulated) and without (unregulated)
preliminary proposed Project operations, with percent flow diverted for power generation.
The regulated hydrograph includes a minimum bypass flow of 1,000 cfs.
Figure 4-5. Schematic of Nuyakuk Falls Reach showing possible adult upstream migration
pathways, adult holding areas, and potential stranding and trapping areas. Photo taken on
June 22, 2017; flows approximately 7,200 cfs.
4.1.2.2 Geographic Scope
Figure 4-6. Approximate Fish Passage Assessment Study Area of the Nuyakuk River.
4.1.2.3 Study Goals and Objectives, and Questions to be Addressed
Figure 4-7. Conceptual representation of potential major effects of Nuyakuk Hydroelectric Project
operations on upstream and downstream fish passage through Nuyakuk Falls, Alaska.
4.1.2.4 Relevant Resource Management Goals
4.1.2.5 Existing Information and Need for Additional Information
Figure 4-8. Area of LiDAR coverage and extent of the Fish Passage Study Area in the Nuyakuk
River, Alaska.
4.1.2.6 Project Nexus
4.1.2.7 Methodology
3.
Define Species Migration Periodicity
Figure 4-9. Estimated monthly periodicities of adult upstream and juvenile downstream migrations
of salmon and estimated average monthly flows of the Nuyakuk River, under unregulated
and regulated conditions, with percent flow diverted for generation.
Establish Species Swimming and Leaping Criteria
Table 4-2. Leaping and Jumping Capabilities of Adult Salmonids, and Preliminary Migration
Periodicity for Nuyakuk River, Alaska (Table modified from Reiser et al. (2006)).
Steelhead Coho Chinook Sockeye Pink Chum
Figure 4-10. Schematics of chute-type (left) and falls-type (right) potential barriers (adapted from
Powers and Orsborn 1985, as presented in Reiser et al. 2006). Variables are defined as
follows: Z is the vertical distance from the bottom of the barrier to the crest of the barrier,
H is the vertical distance from the downstream pool water surface to the water surface at
the crest, dc is the water depth at the crest, dpp is the flow depth of the downstream pool,
LS is the chute length, Sp is the angle of the chute, Se is the angle of the bed upstream of
a falls, FH is the vertical distance from the downstream water surface elevation to the
barrier crest, h0 is the initial leaping angle, and Xsw is the distance from the location of
the impact of the falling water to the standing wave.
Conduct Bathymetric Mapping of Reach
Table 4-3. Topo-bathymetry survey methodology comparisons considered for the Nuyakuk River. MethodSafe or UnsafeQuantitative or Qualitative InterpretationArea-Based or Transect-BasedSingle or Multiple Flow InterpretationLimited or Not Limited by Riparian CoverLimited or Not Limited by Air Entrainment
Develop 2D Hydraulic Model
Conduct Modeling and Evaluate Potential Effects of Project Operations.
Figure 4-11. Schematic of three hypothetical upstream migration routes (Routes 1,2 and 3) each
containing different combinations of Groups/Zones (as defined above) based on hydraulic
parameter limits (e.g., depth, velocity, width, length) that could allow passage of adult
salmonids. More than 3 routes will likely exist within the Falls Reach and these could
overlap/cross, under varying flow levels; e.g., Route 1 may intersect with and become part
of Route 2, Route 3 may intersect with 2 and 1, etc. Some pathways may actually lead to
dead-ends forcing fish to move back downstream and attempt another route. A time
series analysis covering distinct upstream migration periods will be completed using
different water year types to allow a comparative assessment of Upstream Passage
Probabilities under different flow conditions.
Figure 4-12. Schematic of three hypothetical downstream migration routes defined via 2D
modeling. A time series analysis covering distinct downstream migration periods will be
completed using different water year types will allow a comparative assessment of
Downstream Passage Probabilities under different flow conditions.
Figure 4-13. Depiction of potential changes in upstream migration probability as a function of
changes in physical and hydraulic conditions within the Falls Reach, and potential delay at
the tailrace (R) and passage probabilities both with operations and without (current).
Similar analysis would be applied under a Climate Change scenario as a function of flow
changes, not temperature.
Figure 4-14. Depiction of potential changes in downstream migration probability as a function of
changes in passage probabilities due to delay, stranding/trapping or entrainment and
passage probabilities both with operations and without (current). Similar analysis would
be applied under a Climate Change scenario as a function of flow changes, not
temperature.
Figure 4-15. Example passage analysis denoting the ranges of flows that afford suitable passage
conditions for different species. The dashed vertical lines represent the flow window that
is suitable for all species. The PHABSIM and Tennant flows represent flows recommended
via habitat and hydrologic analysis. (Adopted from Reiser et al. 2006). A similar type of
analysis could be applied in the Nuyakuk Falls Reach.
Table 4-4. Downramping rates proposed by Hunter (1992) to minimize stranding and trapping
impacts on salmonids (From Reiser et al. 2007)
Season Daylight Rates1 Night Rates
1 Defined as one hour before sunrise to one hour after sunset
4.1.2.8 Proposed Deliverables and Schedule
4.1.2.9 Level of Effort and Cost
4.1.3 Fish Entrainment and Impingement Study
4.1.3.1 General Description of Proposed Study
4.1.3.2 Geographic Scope
Figure 4-16. Fish Entrainment and Impingement Study Area.
4.1.3.3 Study Goals and Objectives
4.1.3.4 Relevant Resource Management Goals
4.1.3.5 Existing Information and Need for Additional Information
4.1.3.6 Project Nexus
4.1.3.7 Methodology
Use Existing Information to Inform Preliminary Design
Hydrology, Flow Routing, and Hydraulic Modeling
Entrainment
Table 4-5. Relevant fish entrainment study reports for FERC projects compiled by Nushagak
Cooperative.
FERC Project Study Report Citation
Impingement
Mortality
4.1.3.8 Proposed Deliverables and Schedule
4.1.3.9 Level of Effort and Cost
4.1.4 Assessment of False Attraction at the Tailrace Fish Barrier
4.1.4.1 General Description of Proposed Study
4.1.4.2 Geographic Scope
Figure 4-17. Assessment of False Attraction at the Tailrace Fish Barrier Study Area.
4.1.4.3 Study Goals and Objectives
4.1.4.4 Relevant Resource Management Goals
4.1.4.5 Existing Information and Need for Additional Information
4.1.4.6 Project Nexus
4.1.4.7 Methodology
Review Existing Information to Inform Preliminary Design
Feasibility evaluation
Preliminary design of tailrace exclusion refinements
4.1.4.8 Proposed Deliverables and Schedule
4.1.4.9 Level of Effort and Cost
4.1.5 Chinook and Sockeye Salmon Life Cycle Modeling
4.1.5.1 General Description of Proposed Study
4.1.5.2 Geographic Scope
4.1.5.3 Study Goals and Objectives
4.1.5.4 Relevant Resource Management Goals
4.1.5.5 Existing Information and Need for Additional Information
4.1.5.6 Project Nexus
4.1.5.7 Methodology
Justification for an LCM
Components of the LCM
Tasks
Task 1: Model Development
Task 2: Data Acquisition
o
o
o
Task 3: Calibrate Baseline Model
Task 4: Develop Baseline Model and Calculate Model Sensitivity
Task 5: Develop Expected Project Effects
Task 6: Incorporate Future Climate and Water Flow Scenarios
Task 7: Evaluate Project Effects
4.1.5.8 Proposed Deliverables and Schedule
Task 1
Task 2
Task 3
Task 4
Task 5
Task 6
Task 7
Schedule
Figure 4-18. Nuyakuk Falls Fish Life Cycle Modeling Study Schedule. 2023 and 2024 are projected
to be Year 1 and Year 2, respectively.
4.1.5.9 Level of Effort and Cost
4.1.6 Integrated Risk Assessment of Fish Populations
4.1.6.1 General Description of Proposed Study
4.1.6.2 Geographic Scope
4.1.6.3 Study Goals and Objectives
4.1.6.4 Relevant Resource Management Goals
4.1.6.5 Existing Information and Need for Additional Information
4.1.6.6 Project Nexus
4.1.6.7 Methodology
Approach for a Qualitative Integrated Risk Analysis
Table 4-6. Hypothetical risk assessment summary with example risk values for Chinook Salmon and potential risk sources. Values are imported from Table 4-8. Management Objective (e.g., sustainable population)Sockeye SalmonChinook SalmonCoho SalmonPink SalmonChum SalmonArctic CharNorthern PikeBurbot Whitefish Sculpin Total?Risk SourcesChange to Flow regime during upstream migrationChange to flow during downstream migrationFalse attraction at tailraceRates of flow change (stranding/trapping)Entrainment…. Change to flow regime during rearingTotal?
Table 4-7. Hypothetical risk assessment table for one risk source impacting one specific management objective element. This example is concerned with expected reductions in downstream passage success for Chinook salmon from modifications to the flow regime. The values in the table are possible outcomes calculated by multiplying the ranking of likelihood by the ranking of consequence. Each consequence level is evaluated for a likelihood. Highlighted cells provide example selections for an individual risk source and element pair, including uncertainty. The lowest highlighted value (-4) is used in Table 4-8 to represent the consequence-likelihood of maximum risk (in this case, a minor negative impact that is likely) for this risk source / element pair.Risk Source:Flow regimeElement: Downstream passage success Likelihood of occurrenceNo Possibility Remote Unlikely Possible LikelyMagnitude of impactRank Value 0 1 2 3 4 Consequence Level Major negative -2Minor negative -1No consequence 0Minor positive 1Major positive 2
Table 4-8. Hypothetical risk assessment table for one management objective and species (population sustainability of Chinook), by risksource and ranked elements. The values for each element column are derived from an individual risk analysis table (e.g., highlighted consequence and likelihood value of -4 from Table 4-7. All other values for demonstration only). The values of this table will be used in Table 4-6 respective of management objective, risk source and species.Chinook Elements of the management objectiveMaximum RiskNexus: 1,2 1,2 1,2,3 1,2,3 1,4 2,3PredationStress/ EnergeticsSpawning Habitat AreaRearing Habitat AreaUpstream passage successDownstream passage successRisk SourceChange to flow regime during upstream migrationChange to flow regime during downstream migrationFalse attraction at tailraceRates of flow change (stranding/trapping)EntrainmentChange to flow regime during rearing
4.1.6.8 Deliverables and Schedule
4.1.6.9 Level of Effort and Cost
4.1.7 Future River Flows and Water Temperatures Study
4.1.7.1 Overview
4.1.7.2 General Description of Proposed Study
Trends in the Region
Nuyakuk Watershed Hydrology
Figure 4-19. This analysis of the Nuyakuk Gage at Tikchik Lake Outlet (USGS #15302000) indicates
the onset of spring runoff begins 20 days earlier now. November and December flow were
higher the last two decades then in any time from 1954 - 2000.
Relevant Climate Studies
Figure 4-20. Observed and projected changes (compared to the 1925–1960 average) in near surface
air temperature for Alaska as a whole. Observed data are for 1925–2020, while model
simulations of the historical period are shown for 1901–2005. Projected changes for 2006–
2100 are from global climate models for two possible futures: one in which greenhouse gas
emissions continue toincrease (RCP8.5, higher emissions) and anotherin which greenhouse
gas emissions increase at a slower rate (RCP 4.5, lower emissions). Temperatures in Alaska
(orange line) have increased by about 3.5°F since 1925 but with large multidecadal
variations. Shading indicates the range of annual temperatures from the set of models.
Observed temperatures are generally within the envelope of the modeled historical
simulations (gray shading). Historically unprecedented warming is projected during this
century. Less warming is expected under a lower emissions future (the coldest end-of-
century projections being about 2°F warmer than the historical average; green shading) and
more warming under a higher emissions future (the hottest years being about 15°F warmer
than the hottest year in the historical record; red shading). Sources: CISESS and NOAA
NCEI, Figure 1 in Stewart et al2022.
Figure 4-21. Monthly changes in future temperature and precipitation projected for five GCMs
(Figure 3 in Wobus et al. 2018).
Figure 4-22. Average daily flow for each May at USGS gage record at Tikchik Lake outlet. The 69
years exhibit an upward trend due to earlier snowmelt, with current flows almost double
those of the early 1950s (~3,500 vs ~6,500 cfs). Flows were consistently between 2,000 and
6,000 cfs from 1954 to 1975. From 1975 to 1995 average May flows above 6,000 cfs occur in
33 percent of the years. After 2002, average May flows are more likely to be above 10,000 cfs
than below 4,000 cfs - the average those first 30 years. Average May flows have not been
below 4,000 cfs in eightyears.
Figure 4-23. Average daily flow for each November at USGS gage record at Tikchik Lake outlet.
The trend over the past 69 years is for about 50% more flow in the present. Note the
interannual variability of the flows (e.g. 2019, 2020, and 2021, or 1979, 1980 and 1981). Note
that there are some missing years of data in the late 1990s.
4.1.7.3 Geographic Scope
4.1.7.4 Study Goals and Objectives
4.1.7.5 Relevant Resource Management Goals and Public Interest Considerations
4.1.7.6 Existing Information and Need for Additional Information
4.1.7.7 Project Nexus
4.1.7.8 Methodology
7 Ibid.
4.1.7.9 Level of Effort and Cost
4.2 Water Resources
4.2.1 Water Quality Assessment – Dissolved Oxygen and Water Temperatures
4.2.1.1 General Description of Proposed Study
4.2.1.2 Geographic Scope
4.2.1.3 Study Goals and Objectives
4.2.1.4 Relevant Resource Management Goals
4.2.1.5 Existing Information and Need for Additional Information
4.2.1.6 Project Nexus
4.2.1.7 Methodology
4.2.1.8 Proposed Deliverables and Schedule
4.2.1.9 Level of Effort and Cost
4.2.2 Flow Duration Curve Change Assessment
4.2.2.1 General Description of Proposed Study
4.2.2.2 Geographic Scope
4.2.2.3 Study Goals and Objectives
4.2.2.4 Relevant Resource Management Goals and Public Interest Considerations
4.2.2.5 Existing Information and Need for Additional Information
4.2.2.6 Project Nexus
4.2.2.7 Methodology
4.2.2.8 Proposed Deliverables and Schedule
4.2.2.9 Level of Effort and Cost
4.2.3 Ice Processes Assessment
4.2.3.1 General Description of Proposed Study
4.2.3.2 Geographic Scope
4.2.3.3 Study Goals and Objectives
4.2.3.4 Relevant Resource Management Goals
4.2.3.5 Existing Information and Need for Additional Information
4.2.3.6 Project Nexus
4.2.3.7 Methodology
4.2.3.8 Proposed Deliverables and Schedule
4.2.3.9 Level of Effort and Cost
4.3 Terrestrial Resources
4.3.1 Botanical and Wetlands Survey
4.3.1.1 General Description of Proposed Study
4.3.1.2 Geographic Scope
4.3.1.3 Study Goals and Objectives
4.3.1.4 Relevant Resource Management Goals
4.3.1.5 Existing Information and Need for Additional Information
4.3.1.6 Project Nexus
4.3.1.7 Methodology
Study Component #1 – General Vegetation Type/Wetland Mapping
Study Component #2 – Field Vegetation Surveys/Wetland Delineation
4.3.1.8 Proposed Deliverables and Schedule
Study Component #1 – General Vegetation Type/Wetland Mapping
Study Component #2 – Field Vegetation Surveys/Wetland Delineation
4.3.1.9 Level of Effort and Cost
4.3.2 Caribou Population Evaluation
4.3.2.1 General Description of Proposed Study
4.3.2.2 Geographic Scope
Figure 4-24. Range of the Mulchatna caribou herd (MCH) and permitted hunt area specific to this
herd (RC503) in Southwest Alaska (Barten and Watine 2020).
4.3.2.3 Study Goals and Objectives
4.3.2.4 Relevant Resource Management Goals
4.3.2.5 Existing Information and Need for Additional Information
4.3.2.6 Project Nexus
4.3.2.7 Methodology
4.3.2.8 Proposed Deliverables and Schedule
4.3.2.9 Level of Effort and Cost
4.4 Cultural Resources
4.4.1 Subsistence Study
4.4.1.1 General Description of Proposed Study
4.4.1.2 Geographic Scope
4.4.1.3 Study Goals and Objectives
4.4.1.4 Relevant Resource Management Goals
4.4.1.5 Existing Information and Need for Additional Information
4.4.1.6 Project Nexus
4.4.1.7 Methodology
4.4.1.8 Proposed Deliverables and Schedule
4.4.1.9 Level of Effort and Cost
4.4.2 Section 106 Evaluation
4.4.2.1 General Description of Proposed Study
4.4.2.2 Geographic Scope
4.4.2.3 Study Goals and Objectives
4.4.2.4 Relevant Resource Management Goals
4.4.2.5 Existing Information and Need for Additional Information
4.4.2.6 Project Nexus
4.4.2.7 Methodology
4.4.2.8 Proposed Deliverables and Schedule
4.4.2.9 Level of Effort and Cost
4.5 Recreation and Aesthetic Resources
4.5.1 Noise Study
4.5.1.1 General Description of Proposed Study
4.5.1.2 Geographic Scope
4.5.1.3 Study Goals and Objectives
4.5.1.4 Relevant Resource Management Goals
Figure 4-25. Proposed Noise Study Area.
4.5.1.5 Existing Information and Need for Additional Information
4.5.1.6 Project Nexus
4.5.1.7 Methodology
4.5.1.8 Proposed Deliverables and Schedule
4.5.1.9 Level of Effort and Cost
4.5.2 Recreation Inventory by Season
4.5.2.1 General Description of Proposed Study
4.5.2.2 Geographic Scope
4.5.2.3 Study Goals and Objectives
4.5.2.4 Relevant Resource Management Goals
4.5.2.5 Existing Information and Need for Additional Information
Figure 4-26. Recreation Study Area
4.5.2.6 Project Nexus
4.5.2.7 Methodology
o
o
o
o
o
o
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o
o
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o
o
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4.5.2.8 Proposed Deliverables and Schedule
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4.5.2.9 Level of Effort and Cost
4.6
4.6.1
Environmental Justice
General Description of Proposed Study
4.6.2 Geographic Scope
4.6.3 Study Goals and Objectives
4.6.4 Relevant Resource Management Goals
Figure 4-27. Geographic scope of Environmental Justice study.
4.6.5 Existing Information and Need for Additional Information
4.6.6 Project Nexus
4.6.7 Methodology
Table 4-9. Environmental Justice Data Table Example.
RACE AND ETHNICITY DATA
LOW-
INCOME
DATA
Geography Total
Population
(count)
White
Alone
Not
Hispanic
(count)
African
American
(count)
Native
American/
Alaska
Native
(count)
Asian
(count)
Native
Hawaiian
& Other
Pacific
Islander
(count)
Some
Other
Race
(count)
Two or
More
Races
(count)
Hispanic
or
Latino
(count)
Total
Minority
(%)
Below
Poverty
Level (%)
State
Native
Regional
Corporation
County or
Borough
Census
Tract X,
Block Group
X
4.6.8 Proposed Deliverables and Schedule
4.6.9 Level of Effort and Cost
4.7 Supplemental Study – Economic Decision Support Tool
4.7.1 General Description of Proposed Study
4.7.2 Geographic Scope
4.7.3 Existing Information and Need for Additional Information
4.7.4 Methodology
Figure 4-27. Example GUI output.
5.0 STUDY SCHEDULE AND PROCESS
6.0 REFERENCES
Sotiropoulos
APPENDIX A:
PAD Comment Responses
Table 1. Comments received on the Pre-Application Document (PAD) for the Nuyakuk River Hydroelectric Project (P-14873) and Nushagak Cooperative's responses.
APPENDIX B:
PAD Comments and Study Requests Filed with FERC
REFERENCES
333 Raspberry Road
Anchorage, Alaska 99518-1565
Main: 907.267.2294
Fax: 907.267.2422
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APPENDIX C:
Nexus Between the Project and Fish Populations, by Proposed Fish Study
1. Appendix C – Nexus Between the Project and Fish Populations, by Proposed Fish Study The potential for the Project to impact the fish community and aquatic habitats in the Project vicinity will be evaluated with the six studies proposed in Section 4. This appendix provides the foundation that was used for study development. The first section, Project Nexus Statements characterize the connections from Project-related changes to potential impacts and identifies the questions that the studies will address, as well as likely monitoring and adaptive management that may be required once the Project is operating. The second section is a list of specific hypotheses that will be addressed through implementation of the empirical and modeling studies. These will be synthesized with the Integrated Risk Assessment to provide a comprehensive assessment of potential Project impacts of the fish community and aquatic habitats in the vicinity of the Project. 2. C1. Project Nexus Statements Primary Nexus: Project operations will divert river water through the powerhouse and return it to the river below the Falls Reach via a tailrace, so fish habitat will be affected via decreased flow through the Falls. Regional climate will determine the flow and temperature of water entering the Project Area and may affect operations (due to flow changes) or have effects on fish (due to flow and water temperature changes). Secondary Nexus: Physical Project components (e.g., groin, intake, tailrace) will replace existing fish habitat with flow control structures upstream and downstream of the Falls thereby altering habitat characteristics at those locations. Note: Each Nexus statement (1a through 4a) below is written with the preface of “Project structure and/or operations may have a potential effect on, e.g., 1a Upstream passage behavior and survival of fish through the Falls Reach”, etc.
Table 1. NuyakukRiver Hydroelectric Project Nexus with Aquatic Habitats and Functions: Potential Impacts on the Timing, Distribution, and Overall Success of Fish Moving Upstream and Downstream Through the Falls Reach (defined as the river reach from the point of proposedintake to the downstream end of the pool adjacent to the proposed tailrace). This Nexus relates to downstream passage via powerhouse entrainment or the Falls Reachin Nexus #2a, and stranding/trapping in Nexus #3a.Project Nexus #1aUpstream passage, behavior and survival of fish through the Falls ReachStructural/Operational Source of ImpactRiver flow will be diverted above the Falls proper and through the powerhouse at a variable rate. Some river habitat will be replaced with water conveyance structures.Conditions/Habitats Affected Upstream passage conditions and habitats within the Falls Reach of the Nuyakuk River. Potential changes in conditions/habitats Will reduce the quantity of river flow and distribution of flow through the Falls Reachand alter the depth/velocity distributions and the quantity and composition of habitats suitable for upstream passage. Potential effects on fish 3.Changes in depth, velocity and habitat composition may impair or improve upstream fish passageconditions (variable by species and size) compared to baseline and affect their behavior. Reduction inpathways or passage opportunities may affect the timing and distribution of migrating fish and/orreduce numbers of fish upstream of the Project. An increase in pathways or passage opportunities mayalso affect temporal distribution of migrating fish and increased numbers of fish upstream of the Project.4. Reduced total aquatic habitat available for upstream passage may increase fish density and respectivedensity dependent ecological effects (e.g., predation, injury, stress).5. There may be interactive effects between future climate change and flow conditions, including reducedor increased flow overall and during specific seasons. Must consider potential interactive effectsbetween increased temperatures and passage metrics.Metrics and criteria to evaluate the change to habitat and fish passage 1.Metric-Depth and velocity output from 2D modeling under different flow conditions, With and Without-Project.Criteria - Established depth, swimming speed and jumping criteria will be linked to outputs from 2Dmodeling to spatially determine areas of suitable/unsuitable passage under different flow conditions.
Will generate probability distributions of migration pathways (scale TBD; e.g., ranked according to highly likely, likely, possible, unlikely). 2. Metric - Passage success and pathways under different flows, With and Without-Project.Criteria - Comparisons between 2D model predictions and empirical data (measures of passage successand identification of pathways).Comparison between 2D model predictions for attraction and empirical staging times and locations toevaluate potential delay due to conditions in the Falls Reach.Potential ancillary information on fallback/dropback rate, size frequency distribution of run, temporaldistribution, incidence of injury/mortality, and others (Related to Nexus 4a).3. Metric - 2D model predictions linked with Habitat Suitability Criteria (HSC) (e.g., adult holding; adultjumping/plunge pool area), With and Without-Project.Criteria – Comparison of suitable upstream passage related habitat quantities under different flowconditions.4. Metric – Fish density in pathways, With and Without-Project.Criteria – Comparison of modeled fish density in pathways under different flow conditions.5. Metric – Survival to spawning for fish successfully passing the Falls Reach, With and Without-Project.Criteria – Compare probability distributions of latent/pre-spawn mortality.Comparison Basis: - With and Without-Project hydrologic conditions as predicted from 2-D model. Potential for flow fieldchanges to affect behavior of fishes depending on the proportion of flow through the Falls Reach.- Probability distributions of suitable passage metrics and habitat conditions. If probabilities are similar orhigher between With and Without-Project operations, then likely no effect.- Comparison of likelihood estimates of successful passage based on simulations.- For Sockeye and Chinook salmon, probabilities can be linked to the appropriate Life Cycle model todetermine upstream related Project effects on individuals and population.
Operational ConsiderationsTiming and quantity of flow through the Project may be adjusted to minimize risk of negative effects. Engineered manipulations of passage routes could alter flow patterns and direct flows to improve passage conditions within pathways.Monitoring and Adaptive Management Flow based assessments and observations. With-Project evaluation of flow pathways. Assessment of fish passage by observation or trapping in the Falls Reach (movement, jumping, aggregations, predation, pre-spawn mortalities, injuries). Assessment of habitat composition and connectiveness, incidence of fish-unfriendly conditions. Project Nexus #1b Downstream passage and behavior of fish through the Falls Reach Structural/Operational Source of Impact River flow will be diverted above the Falls proper and through the powerhouse at a variable rate. Some river habitat will be replaced with water conveyance structures. Conditions/Habitats Affected Downstream passage conditions and habitats within the Falls Reach of the Nuyakuk River. A new downstream passage route will be available through the Project. A proposed groin upstream of the intake and a tailrace downstream of the powerhouse would change flow fields along the left bank of the river (facing downstream) Potential changes in conditions/habitats Will reduce the quantity of river flow and distribution of flow through the Falls Reachand alter the depth/velocity distributions within pathways used for downstream passage, and the quantity and composition of habitats suitable for downstream passage. Proposed groin adjacent to the intake and a tailrace downstream of the powerhouse could create eddy conditions or change other flow field characteristics. Potential effects on fish1.Changes in depth, velocity and habitat composition may impair or improve downstream fish passageconditions. Migration pathways may change and affect passage run timing (seasonally and diurnally) anddistribution.2. Reduced total aquatic habitat available for downstream passage may increase fish density and respectivedensity dependent ecological effects (e.g., predation, injury, stress).3. Changed hydraulic conditions (e.g., eddy) could delay small fish (e.g., salmon fry or parr) or modify theirdiurnal timing of passage.
4.There may be interactive effects between future climate change and flow conditions, including reducedor increased flow overall and during specific seasons. Consider interactive effect between increasedtemperatures and passage metrics.Metrics and criteria to evaluate the change to habitat and fish passage 1.Metric–Depth, velocity habitat output from 2D modeling under different flow, With and Without-Project.Criteria – Comparison of particle travel times under different flow conditions, Without and With-Project –(assumes passive downstream migration) and compare potential injury risk areas;Assess depth/velocity matrices and drop features within the Falls Reach to identify and compare potentialinjury risk areas (With and Without-Project).2. Metric - Estimates of downstream passage timing through the Falls Reach.Criteria – Compare peak number per day and trends past a location above and below the Project;3. Metric - Vertical and horizontal distribution of downstream migrating fishes in the vicinity of the intake.Criteria – Comparison of relative distribution, Without and With-Project. Modeled flow fieldcharacterization may provide inferences to fish distribution.4. Metric – Fish density in pathways, With and Without-Project.Criteria – Comparison of modeled fish density in pathways under different flow distribution.Comparison Basis: - With and Without-Project hydrologic conditions as predicted from 2-D model. Potential for flow fieldchanges to affect behavior of fishes depending on the proportion flow through the Falls Reach.- Probability distribution of suitable downstream passage metrics and habitat conditions. If theprobabilities are similar or higher between baseline and operations, then likely no effect.- Comparison of likelihood estimates of successful passage based on simulations.- For Sockeye and Chinook salmon, probabilities can be linked to Life Cycle model to determinedownstream related Project effects on individuals and population.Operational ConsiderationsTiming and amounts of flow through the Project may be adjusted to minimize risk of negative effects. Engineered manipulations of passage routes could alter flow patterns and direct flows to improve passage conditions within pathways. Selection of fish friendly turbines will affect passage success through the Project.
Monitoring and Adaptive ManagementFlow based assessments and observations. With-Project evaluation of flow conditions and pathways. Assessment of fish passage by observation or trapping in the Falls Reach (movement, aggregations, predation, injuries). Assessment of habitat composition and connectiveness, incidence of fish-unfriendly conditions. Monitoring of route-specific and overall timing and passage survival. Monitoring for fish delay associated with groin eddy or tailrace. Predator (fish, avian, mammalian) distribution and abundance.Project Nexus #1cRearing habitat in the Falls ReachStructural/Operational Source of ImpactRiver flow will be diverted above the Falls proper and through the powerhouse at a variable rate. Some river habitat will be replaced with water conveyance structures.Conditions/Habitats AffectedRearing habitat (areas for refuge, feeding, holding, moving) for fish within the Falls Reachof the Nuyakuk River.Potential changes in conditions/habitatsWill reduce the quantity of river flow and distribution of flow through the Falls Reachand alter the depth/velocity distributions within rearing habitats, and the quantity and composition of habitats suitable for rearing. Channel configuration, substrate composition, and the composition and configuration of rearing habitat below the Falls proper could be modified. Anticipate seasonal changes associated with operations. Potential effects on fish1.Changes in depth/velocity may reduce or increase the total quantity of rearing habitat (as defined bydepth/velocity suitability indices) in the Falls Reach. Reduced total aquatic habitat may increase fishdensity and respective density dependent ecological effects (e.g., feeding opportunity, predation, injury,stress).2. Changes in habitat below the Falls proper may affect a prime feeding area for resident fish.3. There may be interactive effects between future climate change and flow conditions, including reducedor increased flow overall and during specific seasons. Consider interactive effect between increasedtemperatures and respective metrics.Metrics and criteria to evaluate the change to habitat and fish passage1.Metric-Depth and velocity output from 2D modeling under different flow conditions, With and Without-Project.
Criteria–Comparison of the quantity, composition, and distribution of rearing habitat (e.g., # pools, tail outs) for fish using Habitat Suitability Criteria (HSC) values derived from the 2D model to define the area of habitat under different flow conditions, by different species. Probability distribution of available rearing habitats, With and Without-Project. If the probabilities are similar or higher between baseline and operations, then likely no effect. For Sockeye and Chinook salmon, probabilities could be linked to Life Cycle model to determine the effect of rearing habitat changes in the Falls Reach on individuals and the population as related to Project operations. Metric – Distribution and relative abundance of resident fish below the Falls proper. Criteria – Seasonal distribution and relative abundance changes, With and Without-Project. Comparison Basis: - With and Without-Project hydrologic conditions as predicted from 2-D model. Potential for flow field changes to effect behavior of fishes depending on the proportion flow through the Falls Reach. - Probability distribution of suitable habitat rearing conditions. If the probabilities are similar or higher between baseline and operations, then likely no effect. - For Sockeye and Chinook salmon, probabilities can be linked to Life Cycle model to determine downstream related Project effects on individuals and population.Operational Considerations Timing and quantities of flow through the Project may be adjusted to minimize risk of negative effects to habitat in the Falls Reach. Monitoring and Adaptive ManagementFlow based assessments and observations. With-Project evaluation of flow conditions and pathways. Assessment of habitat use by observation or trapping in the Falls Reach (refuge, feeding, holding, moving, aggregations, predation). Assessment of habitat composition and connectiveness, incidence of fish-unfriendly conditions (e.g., trapping or stranding areas; development of predator (fish, avian, mammalian) stations).
Table 2. NuyakukRiver Hydroelectric Project Nexus with Aquatic Habitats and Functions: Potential Direct and/or Indirect Mortality of downstream moving Fish Due to passing via the powerhouse (entrainment) or the Falls Reach.Relates to stranding/trapping in Nexus 3a.Project Nexus 2a Downstream passage and survival. Fish may pass downstream through the powerhouse (entrainment) or through the Falls Reach. Structural/Operational Source of ImpactRiver flow will be diverted above the Falls proper and through the powerhouse at a variable rate. Some river habitat will be replaced with water conveyance structures.Conditions/Habitats Affected Downstream passage conditions and habitats within the Falls Reach of the Nuyakuk River. A new downstream passage route will be available. Potential changes in conditions/habitats Will reduce the quantity of river flow and distribution through the Falls Reach and alter the depth/velocity distributions within pathways used for downstream passage, and the quantity and composition of habitats suitable for downstream passage in the Falls Reach. Potential effects on fish 1.Changes in depth, velocity and habitat composition may impair or improve downstream fish passage conditions through the Falls Reach compared to baseline. For example, slower velocities and shallower depths may improve survival rates through the reach (less turbulence and potential abrasion, injury). In contrast, lower velocities and depths may predispose fish to lower survival due to predation. Also, an increase of rearing habitats (pools) within the Falls Reach could increase predation risk for downstream migrating salmon. 2. Migration pathways may change and total aquatic habitat available may decrease in the Falls to affect passage survival and respective density dependent ecological effects (e.g., predation, injury, stress). 3. Passage through the Project will offer novel conditions that may result in differential survival and injury as compared to the Falls Reach. Fish survival and physical condition could be affected by abrasion from concrete infrastructure, impingement on gates and screens, strikes with turbines, and predation in or adjacent to the tailrace structure. Differential injury or stress on fish between the routes may potentially cause a higher, latent mortality for route-specific fish after leaving the Project Area. 4. There may be interactive effects between future climate change and flow conditions, including reduced or increased flow overall and during specific seasons. Increased temperature from climate change and
expansion of predator (fish, avian, mammalian)habitat could increase predation rates of small fishes/lifestages. Consider interactive effect between increased temperatures and passage metrics.Metrics and criteria to evaluate the change to habitat and fish passage 1. Metric – Depth, velocity and habitat output from 2D modeling under different flow conditions, With andWithout-Project.Criteria – Proportions of flow through the Project and the Falls Reach, pathways and areas ofsuitable/unsuitable passage, particle travel times;2. Metric – Literature derived estimates of powerhouse passage survival effected by impingement, fish-friendly turbines, and predation in the tailrace.Criteria – Comparison with empirically derived estimates of survival;3. Metric - Estimates of empirically derived downstream survival through the Falls Reach.Criteria – Comparison of rates of downstream passage survival between powerhouse and Falls Reach fish,Without and With-Project.4. Metric – Proportional rate of injury for fish passing the Falls, With and Without-Project, and incidence ofinjury through the powerhouse.Criteria – Compare estimates of injury rate of fish passing through the powerhouse and Falls.Comparison Basis: - Probability distributions of suitable passage metrics and habitat conditions. If probabilities are similar orhigher between With and Without-Project operations, then likely no effect. Comparative analysis ofpredicted injury and mortality between Falls, With and Without-Project, and through Project routes.- Probabilities can be linked to Life Cycle model to determine upstream related Project effects onindividuals and population.Operational ConsiderationsTurbine type, flow distribution across routes and timing, engineering design (gates, screens, tailrace) for higher passage survival in the Falls Reach
Monitoring and Adaptive ManagementFlow based assessments and observations. With-Project evaluation of flow conditions and pathways. Observation of habitat use by fish in the Falls Reach (moving, aggregations). Assessment of habitat composition and connectiveness, incidence of fish-unfriendly conditions. Predator (fish, avian, mammalian) distribution and abundance.
Table 3. Nuyakuk River Hydroelectric Project Nexus with Aquatic Habitats and Functions: Potential Stranding or Trapping of Fishing the Falls proper, and potential dewatering or scouring of spawning habitat below the Falls and tailrace. Due to Rapid Flow Reductions (Down-ramping). Relates to migration pathways and total habitat in Nexus 1b, suitable conditions for rearing in Nexus 1c, and direct/indirect mortality in Nexus 2a. Project Nexus 3aPathways for movement. Potential stranding or trapping of fishes in the Falls Reach Structural/Operational Source of ImpactRiver flow will be diverted above the Falls proper and through the powerhouse at a variable rate. Some river habitat will be replaced with water conveyance structures. Conditions/Habitats AffectedRearing habitats and passage corridors within the Falls Reachof the Nuyakuk River. Potential changes in conditions/habitatsRapid changes in flow operations may result in rapid decreases or increases in flow through the Falls Reach. Some fringe habitats/corridors may become dewatered stranding fish, or as water recedes fish may be trapped in small, isolated pools. Potentialeffects on fish1.Rapid flow changes may render fringe habitats/corridors dewatered or partially dewatered resulting in potential stranding and/or trapping of small fish such as (e.g., salmon fry). Metrics and criteria to evaluate the change to habitat and fish passage 1.Metric-Review of bathymetry and depth and velocity output from 2D modeling to identify areas with a high likelihood for getting disconnected from flow (e.g., perched depressions; gently sloping lateral margins; complex lateral habitats with widely variable topography). Criteria - Evaluate and compare stranding and trapping potential by running different operational ramping rate scenarios and seeing how identified risk areas respond in terms of the timing to disconnection, trapping and stranding, and the total areas affected. Quantify and characterize identified areas as high or low likelihood. High concern area is characterized as areas that are perched
and highly sensitive to flow changes; low concern areas have depressions that only become disconnected under extremely low flow conditions. 2. Metric – modeled rate of mortality for fish stranded/trapped.Criteria - use life cycle model and a distribution of mortality rate for sensitivity analysis ofstranding/trapping under flow scenarios.Comparison Basis: - Comparison of (a) total trapping/stranding area (m2) under With and Without-Project operations, and(b) modeled mortality estimates With and Without-Project based on different down-ramping rates.- Results linked to life cycle model as source of influence on juvenile/smolt/fry survival rates through theFalls Reach.Operational ConsiderationsRate of change in flow directed through the turbines. Sequence and timing of turbine start up and shut down.Monitoring and Adaptive Management With-Project monitoring of topography of the Falls proper to identify specific locations for fish stranding and or trapping low flow condition. Monitor program during downstream fish migration during; conduct post – flow change monitoring of areas at risk to see if any trapping or stranding has occurred. Project Nexus #3b Spawning habitat below Falls and tailrace. Potential for dewatering or scouring. Structural/Operational Source of ImpactOperational changes in flow rate and distribution through the powerhouse and the Falls Reach. Conditions/Habitats AffectedPotential spawning habitats downstream of the Falls and tailrace. Potential changes in conditions/habitatsChanges in operations may result in decreases or increases in flow through the Falls Reach. Decreases may result in some fringe habitats used for spawning (if present) to become dewatered. Rapid increases may result in some scouring of these areas. Water flow, water elevation, river channel configuration, and distribution of substrate composition may create suitable spawning habitat in new locations.
Potential effects on fish1.Flow reductions may render fringe spawning habitats dewatered or partially dewatered resulting in potential egg desiccation or reduced embryo survival (reduced intragravel velocities).2. Rapid flow increases may scour redds and dislodge eggs/embryos.3. Suitable habitat for spawning may be created by new hydraulic conditions of the Project. 4. There may be interactive effects between future climate change and flow conditions, including reduced or increased flow overall and during specific seasons. Consider interactive effect between increased temperatures and passage metrics. Metrics and criteria to evaluate the change to habitat and fish passage 1.Metric–Evaluate2D model flow field and water elevations below the Falls and tailrace over several operational scenarios including different ramping rates, to determine whether and extent to which potential spawning areas might be affected (dewatered, scoured etc.). Criteria – Identify flow field and elevation changes may result in potentially erosive or dewatering conditions, or the development of new suitable spawning locations. 2. Metric - Observations and demarcation of spawning gravel distributions downstream of the Falls proper, including within and downstream of the proposed tailrace. If possible, collect substrate samples to verify size classes present. Criteria - If spawning observed, review output form 2D model to define areas where potential changes in operational flows could dewater or scour redds. Relate potential impact area to potential for fish incubation effects based on estimates of redds/square meter and embryo per redd estimates obtained from the literature. Comparison Basis: - Comparison of (a) area of spawning/incubation habitat under With and Without-Project operations, and (b) potential effects to embryo mortality under With and Without-Project operations. - Results linked to life cycle model as source of influence on juvenile/smolt/fry survival rates through the Falls Reach. Operational ConsiderationsTiming and sequence of turbine start up and shut off. Rate of change of intake flow through the powerhouse.
Monitoring and Adaptive ManagementWith-Project observational monitoring for redds for the area downstream of the Falls proper to downstream of the tailrace. The area of interest may modify depending on shifts in channel in substrate because of Project operations.
Table 4. Nuyakuk River Hydroelectric Project Nexus with Aquatic Habitats and Functions: Potential migration delay and injury may result in the delayed passage timing and/or latent mortality of fish moving upstream due to false attraction to the tailrace or changes in habitat below the Falls proper. Relates to upstream moving fish in Nexus 1a.Project Nexus #4a Timing, behavior, and passage routes of upstream moving fish entering the Falls proper.Structural/Operational Source of Impact Operational changes in flow rate and distribution through the powerhouse/tailrace and the Falls Reach. Some river habitat will be replaced with water conveyance structures. Conditions/Habitats Affected Flow field and the proportion of flow coming through the Falls Reachand tailrace. Channel configuration and habitats below the Falls proper could be modified. Potential changes in conditions/habitatsProject operations will result in a higher proportion of flow in the tailrace compared to the FallsReachtailout and may change the flow field, channel configuration, and water depths/velocity below the Falls proper. The composition, configuration, connectivity, and suitability of holding/staging/migration/ascension habitats downstream of the Falls proper and tailrace may change. Potential effects on fish1.Changes in holding/staging/migration/ascension habitats below the Falls proper may become lesssuitable or connected and result in delayed passage through the Falls or higher rates of injury.Anadromous migrants may have higher rate of latent mortality prior to spawning. Resident migrantsmay arrive later or not at all to destinations associated with their life history.2. Upstream migrating fish may be attracted to the predominant flow of the impassible route of thetailrace and thereby be delayed in finding the migration pathway into the Falls proper or subject tohigher rates of injury.3. Adult salmon attracted to turbine discharge into the tailrace could be injured jumping at draft tubes orother structures.4. Fish may expend additional energy related to 1) the alteration of holding /staging/migration/ascensionhabitat immediately below the Falls proper or 2) time and effort being falsely attracted to the tailraceand result in premature mortality.
Metrics and criteria to evaluate the change to habitat. 1.Metric -Depth and velocity output from 2D modeling under different flow conditions (With andWithout-Project).Criteria - Identification and assessment of potential changes to holding/staging/migration/ascensionhabitats (quantity, composition and flow characteristics) and the effect on migration into the Falls proper.2. Metric – Assessment of the mixing of flow fields from the tailrace and Falls Reach. May provide anindication of potential for and severity of false attraction to the tailrace.Criteria - Depth and velocity vector values can be compared to standards developed by NMFS for fishpassage at hydropower facilities.3. Metric - Observations or telemetric data of numbers and timing of fish holding/milling/searchingimmediately downstream of the Falls proper and tailrace compared to numbers successfully passing theFalls Reach (i.e., above the Project).Criteria – A relative increase in the number of fish below the Falls proper compared to the numberpassing the Falls proper may indicate a delay in passage timing. Fish holding/milling for extended time atlocations further downstream With-Project.4. Metric - Ratio of number migrants upstream versus downstream of the Falls Reach, With and Without-Project.Criteria – A decrease in ratio would indicate fewer migrants are successfully passing the Falls Reach.5. Metric – Observed rate of injury or mortality of fish below the Falls proper and tailrace. Observation ofmigration jumping at unpassable structures.Criteria – Observed higher incidence of injury or mortality With-Project may indicate unsuitable habitatconditions. Information gleaned from analysis can be parameterized into Life cycle model as a mortalityfactor.6. Metric – use life cycle model analyses to address the potential energy expenditure effect (#4).Criteria – Assess the potential quantity of delay time that would cause latent pre-spawn mortality inmigrating salmon due the additional energy used during the delay.Comparison Basis: -Rates of injury, delay, milling compared to expected values.
Operational ConsiderationsEngineered modifications to tailrace outflow, rerouting of flow from turbines, physical methods to prevent fish from entering the tailrace Monitoring and Adaptive Management Monitoring of fish behavior at tailrace and in the holding pool downstream of the Falls. Estimates of injury and mortality in the tailrace. Monitoring of passage success.
3. C2. Hypothesis StatementsNull Hypothesis Alternative Hypothesis Example Values Example MetricComparative metrics for pre-and With-Project conditions, given natural variability.The metrics for Hypotheses 2,3,4,5,7 are intended for sensitivity analysis with the Life Cycle Model to ascertain the magnitude to which these relations may be important in the risk analysis. However, this does not exclude the potential need for validation of the relationships that are demonstrated to be sensitive to change and form the basis of collecting the necessary empirical data for the Nuyakuk (e.g., tower counts of adults and hydroacoustic counts of juveniles for salmon). Blue shade indicates a sequence which potentially leads to reduced long term production and sustainability of the population. DIRECT Effect -H1N. The probability of upstream passage success through the Falls will be similar. Life Cycle Transition 1. Metric(s) 1a2 H1A1. The probability of upstream passage success through the Falls will be significantly lower under With-Project conditions relative to Without-Project.Without-Project = 0.90With-Project = 0.80 Probability of upstream passage success through the Falls (from a calibrated fish passage model). A lower probability can result in a decreased population. H1A2. The probability of upstream passage success through the Falls will be significantly higher under With-Project conditions relative to Without-Project. Without-Project = 0.90With-Project = 1.0 DIRECT Effect - H2N. The ratio of upstream-Project to downstream-Project adult migrants will be similar. Life Cycle Transition 1. Metric(s) 4a4 H2A1. The ratio of upstream-Project to downstream-Project adult migrants will be significantly lower (i.e., relative decrease in spawners upstream the Project) under With-Project conditions relative to Without-Project.Without-Project = 0.90 (9:10)With-Project = 0.80 (8:10) Number of adult migrants upstream-Project and downstream-Project. A lower ratio can indicate a lower passage success and can result in a decreased population. H2A2. The ratio of upstream-Projectto downstream-Project adult migrants will be significantly higher (i.e., relative increase in spawners upstream the Project) under With-Project conditions relative to Without-Project. Without-Project = 0.90 (9:10)With-Project = 1.0 (10:10)
INDIRECT Effect -H3N. The ratio of upstream-Project juvenile migrants to upstream-Project adult migrants will be similar. Life Cycle Transition 2. Metric(s) 1b2, 4a4 H3A1. The ratio of upstream-Project juvenile migrants to upstream-Project adult migrants will be significantly lower (i.e., relative increase in adult delayed mortality through the Project) under With-Project conditions relative to Without-Project.Without-Project = 100.0 (100:1)With-Project = 50.0 (50:1) Number of juvenile migrants upstream-Project and number of adult migrants upstream-Project. A lower ratio can indicate fewer successful spawners and result in a decreased population. H3A2. The ratio of upstream-Project juvenile migrants to upstream-Project adult migrants will be significantly higher (i.e., relative decrease in adult delayed mortality through the Project) under With-Project conditions relative to Without-Project. Without-Project = 100.0 (100:1) With-Project = 150.0 (150:1) DIRECT Effect -H4N. The ratio of downstream-Project juvenile migrants to upstream-Project juvenile migrants will be similar. Life Cycle Transition 3. Metric(s) 1b2 H4A1. Ratio of downstream-Project juvenile migrants to upstream-Project juvenile migrants will be significantly lower (i.e., relative decrease in juvenile outmigrants downstream the Project). Without-Project = 0.90 (9:10) With-Project = 0.80 (8:10) Number of juvenile migrants downstream-Project and upstream-Project. A lower ratio indicates lower survival and can result in a decreased population. H4A2. Ratio of downstream-Project juvenile migrants to upstream-Project juvenile migrants will be significantly higher (i.e., relative increase in juvenile outmigrants downstream the Project). Without-Project = 0.90 (9:10)With-Project = 1.0 (10:10)
INDIRECT Effect -H5N. The ratio of downstream-Project juvenile migrants by brood year to downstream-Project returning adult migrants by brood year, compared to ratios observed in other systems, will be similar. Life Cycle Transition 4. Metric(s) 1b2, 4a4 H5A1. The ratio of downstream-Project returning adult migrants by brood year to downstream-Project juvenile migrants by brood year, compared to ratios observed in other systems, will be significantly higher (relative increase of juvenile delayed mortality passing through the Project).Without-Project = 0.10 (1:10)With-Project = 0.05 (1:20) Number of adult migrants downstream-Project and juvenile migrants downstream-Project and (brood analysis). Higher ratio indicates fewer adult returns per juvenile and may result in a decreased population. H5A2. The ratio of downstream-Project returning adult migrants by brood year to downstream-Project juvenile migrants by brood year, compared to ratios observed in other systems, will be significantly lower (i.e., relative decrease of juvenile delayed mortality passing through the Project). Without-Project = 0.10 (1:10) With-Project = 0.15 (1:7) Direct Effect -H6N. The quantity of suitable rearing habitat in the Falls Reach will be similar. Life Cycle Transition 3. Metric(s) 1c1 H6A1. The quantity of suitable rearing habitat in the Falls Reach will be significantly lower under With-Project conditions relative to Without-Project.Without-Project = 1 haWith-Project = 0.5 ha Quantity (hectare) of suitable rearing habitat in the Falls Reach as defined by depth and velocity as index of effect on survival. A lower survival can result in a decreased population. H6A2. The quantity of suitable rearing habitat in the Falls Reach will be significantly higher under With-Project conditions relative to Without-Project. Without-Project = 1 haWith-Project = 1.5 ha
Direct Effect -H7N. The survival of downstream migrants through the Falls Reach and the powerhouse will be similar. Life Cycle Transition 3. Metric(s) 2a2, 2a3, 2a4 H7A1. Survival of downstream migrants through the powerhouse (literature) will be significantly lower than Without-Project through the Falls Reach (empirical).Falls Reach= 95%powerhouse = 85% Proportion of downstream migrants surviving through the powerhouse and Falls Reach. A lower survival can result in a decreased population. With-Project survival through the powerhouse may be empirical. H7A2. Survival of downstream migrants through the powerhouse (literature) will be significantly higher than Without-Project conditions through the Falls Reach (empirical). Falls Reach= 95%powerhouse = 99% Direct Effect - H8N. The survival of downstream migrants through the Falls Reach and tail out will be similar. Life Cycle Transition 3. Metric(s) 2a3, 2a4 H8A1. Survival of downstream migrants through the Falls Reach and tail out under With-Project conditions will be significantly lower than Without-Project. Without-Project = 95% With-Project = 85% Empirical proportion of downstream migrants surviving through the Falls Reach and tail out. A lower survival can result in a decreased population. This comparison is conducted if the Project is built. H8A2. Survival of downstream migrants through the Falls Reach and tail out under With-Project conditions will be significantly higher than Without-Project. Without-Project = 95% With-Project = 99%
Direct Effect -H9N. The risk of stranding/trapping of small fish in the Falls Reach will be similar Pre-vs - Post Project. Life Cycle Transition 3. Metric(s) 3a1, 3a2 H9A1. The risk of stranding/trapping of small fish With-Project will be significantly higher than Without-Project.Without-Project = 0.5With-Project = >0.6 Estimated risk will be determined by channel bathymetry/topography in relation to flow reduction associated With-Project operations. Will then look at range of typical flow changes over different time periods Pre- and Post- Project operations to see to what extent stranding/trapping may occur within those areas. H9A2. The risk of stranding/trapping of small fish With-Project will be significantly lower than Without-Project.Without-Project = 0.5With-Project = <0.4 Direct Effect - H10N. The modeled total area of potential dewatering or erosion of spawning habitat in the powerhouse tailrace and Falls Reach tail out will be similar. Life Cycle Transition 3. Metric(s) 3b1, 3b2 H10A1. The total area of potential dewatering or erosion of spawning habitat will be significantly higher With- versus Without-Project conditions. Without-Project = 1 ha With-Project = 1.5 ha Modeled area of potential dewatering or erosion of spawning habitat (defined by suitability criteria) as an index of effect on juvenile production in the powerhouse tailrace and Falls Reach tail out. Decreased spawning habitat can result in decreased production and population.H10A2. The total area of potential dewatering or erosion of spawning habitat will be significantly lower With- versus Without-Project conditions. Without-Project = 1 haWith-Project = 0.5 ha
Direct and Indirect Effect -H11N. The modeled flow field (velocity vectors and depth) in the Falls Reach tail out will provide similar upstream migration attraction cues to current conditions in the Falls Reach. Life Cycle Transition 1. Metric(s) 4a1, 4a2, 4a5 H11A1. With-Project water velocity vectors and depth in the Falls Reach tail out will be significantly different and result in poor upstream migration attraction cues into the Falls Reach relative to Without-Project conditions. Without-Project = within criteriaWith-Project = out of criteria Modeled water velocity vectors and depth in the Falls Reach tail out as an indicator of passage attraction flow. Pre- and With-Project suitability of water velocity and depth in ascension pathways based on physical ability and NMFS attraction flow criteria compared to tailrace flows. Delayed migration can result in increased injury, pre-spawn mortality, and a decreased population.H11A2. With-Project water velocity vectors and depth in the Falls Reach tail out will be significantly different and will result in better upstream migration attraction cues into the Falls Reach relative to Without-Project conditions. Without-Project = within criteriaWith-Project = out of criteria
Direct and Indirect Effect -H12N. Residence times (empirical) of upstream migrants below the Falls Reach will be similar. Life Cycle Transition 1. Metric(s) 4a3, 4a5 H12A1. Residence times of upstream migrants below the Falls Reach will be significantly higher under Without-versus With-Project conditions.Without-Project = TWith-Project = 2T Residence times (empirical) below the Falls Reach as an indicator of false attraction. Delayed migration can result in increased injury and pre-spawn mortality, and a decreased population. Baseline residence times to be compared with With-Project times during monitoring period. This comparison is conducted if the Project is built.H12A2. Residence times of upstream migrants below the Falls Reach With-Project will be similar to Without-Project. Without-Project = TWith-Project = 0.5T
APPENDIX D:
Proposed Study Plan Comment Responses (7/23/2021 Aquatics Resources Work
Group Technical Subcommittee Distribution)
Table 1. Comments received on the Proposed Study Plan (PSP) for the Nuyakuk River Hydroelectric Project (P-14873) distributed to the Aquatics Resources Technical Workgroup (ARWG) on July 23, 2021 and Nushagak Cooperative's responses.
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APPENDIX E:
Proposed Study Plan Comment Responses (9/24/2021 Project Contact List
Distribution)
Table 1. Comments received on the Proposed Study Plan (PSP) for the Nuyakuk River Hydroelectric Project (P-14873) distributed to the Project Contact List on September 24, 2021 and Nushagak Cooperative's responses.
APPENDIX F:
Proposed Study Plan Comments
333 Raspberry Road
Anchorage, Alaska 99518-1565
Main: 907.267.2294
Fax: 907.267.2422
1. Alaska Federation of Natives. 2013. “Alaska Federation of Natives Guidelines for Research.” Alaska Native Knowledge
Network. Accessed June 6, 2020. http://www.ankn.uaf.edu/IKS/afnguide.html
2. National Science Foundation Interagency Social Science Task Force. 2018. “Principles for the Conduct of Research in
the Arctic.” Accessed June 6, 2020. https://www.nsf.gov/geo/opp/arctic/conduct.jsp
3.ADF&G CSIS: http://www.adfg.alaska.gov/sb/CSIS/.
18620 Seward Hwy.
Anchorage, Alaska 99516
Main: 907.345.5014
ANDY WINK, ANCHORAGE, AK.
The Bristol Bay Regional Seafood Development Association (BBRSDA) represents all commercial salmon
driftnet fishermen who operate fishing businesses in the Bristol Bay salmon fishery. Bristol Bay is home
to the world’s most valuable wild salmon fishery and is the region’s economic cornerstone. BBRSDA has
participated in the Aquatic Resources Working Group (ARWG) since 2021 to protect the interests of
commercial fishermen and ensure the project does not jeopardize Bristol Bay’s epic, natural salmon
runs.
BBRSDA fully recognizes the need for affordable power generation in Bristol Bay and we commend the
Nushagak Telephone & Electric Cooperative (NETC) for its proactive efforts to address this need.
However, in the interest of maintaining a robust commercial salmon fishery, we have several comments
about the Proposed Study Plan (PSP) pertaining to the following topics:
1. Defining the “Fish First” directive and ensuring data collection will provide adequate measures to
follow such a policy prior to project construction, as well as monitoring conditions during project
execution.
What is “Fish First?” In November 2017, the NETC Board of Directors adopted a “Fish First” directive
when evaluating any resource utilization. However, this resolution does not define how fishery
resources are to be protected or what an acceptable loss of fish populations may be. Although the Fish
First directive is a noble and reasonable filter for potential resource utilization projects, it is imperative
that it be more specifically defined so that data collection methods can provide useful tools for the
decision-making and public education process. Different people likely have varying definitions of what
they believe the “Fish First” directive means.
Further, it is concerning that the Proposed Study Plan (PSP) does not appear to have a clear and/or
adequate set of data collection methodologies for counting the volume of fish migrating through the
Nuyakuk Falls area. The PSP lays out a goal of developing a Life Cycle Model and Integrated Risk
Assessment tool; however, even the most sophisticated models are useless unless the input data is
sound. BBRSDA is concerned by the PSP document’s lack of a clearly articulated study plan directed at
enumerating fish passage in the project area and the lack of consensus by subject matter experts on the
ARWG regarding how to measure fish passage volume. In the opinion of BBRSDA, the PSP is too
ambiguous about how critical fish data will be collected in a reliable and consistent manner to inform
the LCM, IRA, and “Fish First” specifications – both for the purposes of baseline data and post-
construction monitoring.
Finally on this point, the PSP needs to put forth a specific data collection plan that will allow for reliable
projections about impacts on fish across varying levels of water flow. As this project will redirect river
water during periods of upriver migration, the declining flow through the Nuyakuk Falls could have a
substantial impact on the ability of adult salmon to migrate upriver to spawning beds/
2. Project assumptions regarding long-term demand patterns for electric power generation.
The proposed Nuyakuk Hydroelectic project assumes that for many decades to come, the demand for
electricity will follow the current pattern where load increases substantially during the late spring and
summer months coinciding with the salmon season. Shoreside processing plants consume large
amounts of power to process and freeze salmon. However, it is possible that in the future salmon
processing will shift offshore. In 2019, Northline Seafoods operated such a business in Bristol Bay where
the company froze whole-round salmon on a barge without ever needing to deliver the fish to a
shoreside facility. A storm destroyed that barge when a mooring buoy failed late in 2019, but Northline
founders are looking at options to restart similar operations. BBRSDA has investigated the Northline
whole-round approach and found it to have numerous compelling attributes over the current processing
model used in Bristol Bay.
While it is impossible to predict whether the offshore, whole-round approach will become the new
normal in Bristol Bay in decades to come, we believe it is prudent to point out that there is a reasonable
chance that the current processing model dominated by shoreside facilities may not survive for the next
50-100 years. Therefore, it is important to provide stakeholders with a clear sense of how a potential
shift in processing activity away from shoreside plants may impact the economics of the proposed
project. To what extent does this change the predicted cost per kilowatt? What effect would this shift
have on the project’s cost burden for other NETC customers?
Thank you for the opportunity to comment on this project. Sincerely,
Andy Wink
BBRSDA Executive Director
Field Code Changed
INTERIOR REGION 11 •Alaska
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APPENDIX G:
Proposed Study Plan Comment Responses