HomeMy WebLinkAboutNuyakuk River Hydro Conceptual Design Initial Study Report - Dec 2023 - REF Grant 7013001Nushagak Cooperative, Inc.
Nuyakuk River Hydroelectric Project (P-14873) 1 December 2023
Solutions for the Future
Nushagak Electric & Telephone Cooperative, Inc.
557 Kenny Wren Road P.O. Box 350 Dillingham, AK 99576
Ph: 907-842-5251 Fx: 907-842-2799 www.nushtel.com
December 1, 2023
Secretary Kimberly D. Bose
Federal Energy Regulatory Commission
888 First Street, NE
Washington, DC 20426
- FILED ELECTRONICALLY -
Initial Study Report Filing for the Nuyakuk River Hydroelectric Project (P-14873)
Dear Secretary Bose:
On June 11, 2018 the Federal Energy Regulatory Commission (FERC) issued a Preliminary
Permit to the Nushagak Electric and Telephone Cooperative (Cooperative) for the proposed
Nuyakuk River Hydroelectric Project (Project). On October 7, 2019, the Cooperative filed its
Pre-Application Document (PAD) and Notice of Intent (NOI) and formally entered into the
Integrated Licensing Process (ILP). Upon the filing of the PAD, the Cooperative adhered to
all scheduling milestones and FERC approved modifications associated with the ILP, had
substantial consultation and collaboration with Project stakeholders (kick-off meeting, study
planning meetings, numerous phone calls, etc.) and developed a Proposed Study Plan (PSP)
which was filed with FERC on April 16, 2020.
As FERC is aware, the Project was put into abeyance due to a number of extenuating
circumstances on June 11, 2020. These circumstances included the COVID pandemic,
additional collaboration/agreement time necessary with local stakeholders, the upcoming
commercial fishing season and the potential for a better overall ILP schedule.
By early 2022, conditions were appropriate, and the necessary collaborative dialogue had been
had to lift the abeyance with the Cooperative filing a revised/updated PSP to formally re-
initiate the licensing process. Since that time, a collaboratively developed Revised Study Plan
(RSP) has been developed and filed (8/1/2022), all necessary study preparations and permit
acquisitions have taken place, and the bulk of 2023 was utilized to implement the 1st of two
comprehensive natural resource study seasons. By all accounts (safety, consistency with
methods and a robust dataset), the 2023 study season was a successful first year for the study
program and will assist greatly in assessing the feasibility of the proposed Nuyakuk River
Hydroelectric Project.
With this as context, we hereby file the Initial Study Report (ISR) with FERC. We would also
like to note that our study report meetings are planned for December 5, 2023. Two analogous
meetings will take place; one from 1pm to 4pm and another from 6pm to 9pm (both AK time).
Nushagak Cooperative, Inc.
Nuyakuk River Hydroelectric Project (P-14873) 2 December 2023
Solutions for the Future
Nushagak Electric & Telephone Cooperative, Inc.
557 Kenny Wren Road P.O. Box 350 Dillingham, AK 99576
Ph: 907-842-5251 Fx: 907-842-2799 www.nushtel.com
Both meetings will be held in the Nushagak Cooperative’s Board Room in Dillingham,
Alaska. As has been conveyed to the entire contact list for the Project via email, the
Cooperative’s website, Facebook, local media outlets and direct communications with parties,
there are both in-person and virtual mechanisms for participating in the meetings.
We continue to appreciate all of the genuine collaboration and interest in the potential Project.
We look forward to the upcoming study report meetings, sharing the results from the first
study year and continuing to answer any questions and genuinely collaborate with all
interested parties. Please feel free to contact me (907.842.5251 or wchaney@nushagak.coop)
with any questions regarding this filing.
Will Chaney
Electric Operations Manager/CEO
Nushagak Cooperative
INITIAL STUDY REPORT
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
LIST OF FIGURES .......................................................................................................................iii
LIST OF TABLES.........................................................................................................................iii
ACRONYMS AND ABBREVIATIONS ......................................................................................iv
1.0 INTRODUCTION.............................................................................................................. 1
1.1 Project Description.................................................................................................. 3
1.2 Study Plan Determination Overview...................................................................... 6
1.3 Initial Study Report Meeting .................................................................................. 7
2.0 CURRENT STATUS OF PROJECT LICENSING STUDIES .......................................... 9
2.1 Study Status ............................................................................................................ 9
2.2 Field Camp and Safety Program ........................................................................... 10
3.0 INITIAL STUDY REPORT COMPONENTS................................................................. 11
4.0 STUDY REPORT SUMMARIES.................................................................................... 13
4.1 Characterization of Fish Community Behavior Near the Project Intake
(Attachment A) ..................................................................................................... 13
4.2 Nuyakuk Falls Fish Passage Study (Attachment B) ............................................. 13
4.3 Fish Entrainment and Impingement Study (Attachment C) ................................. 14
4.4 Assessment of False Attraction to the Tailrace Fish Barrier (Attachment D)...... 14
4.5 Chinook and Sockeye Salmon Lifecyle Modeling (Attachment E)...................... 14
4.6 Integrated Risk Assessment of Fish Populations (Attachment F) ........................ 14
4.7 Future Flows Study (Attachment G) ..................................................................... 15
4.8 Water Quality Assessment (Attachment H).......................................................... 15
4.9 Flow Duration Curve Change Analysis Study (Attachment I)............................. 16
4.10 Ice Processes Assessment (Attachment J) ............................................................ 16
4.11 Botanical and Wetlands Survey (Attachment K) .................................................. 16
4.12 Caribou Population Evaluation (Attachment L) ................................................... 17
4.13 Subsistence Study (Attachment M) ...................................................................... 17
4.14 Section 106 Evaluation (Attachment N) ............................................................... 17
4.15 Noise Study (Attachment O)................................................................................. 18
4.16 Recreation Inventory by Season (Attachment P) .................................................. 18
4.17 Environmental Justice Communities (Attachment Q).......................................... 19
4.18 Decision Support Tool (Attachment R)................................................................ 19
4.19 Aesthetic Study (Attachment S)............................................................................ 20
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. ii December 2023
5.0 REFERENCES ................................................................................................................. 21
Attachments
Attachment A – Characterization of Fish Community Behavior Near the Project Intake Study
Report
Attachment B – Nuyakuk Falls Fish Passage Study Report
Attachment C – Fish Entrainment and Impingement Study Report
Attachment D – Assessment of False Attraction to the Tailrace Fish Barrier Study Report
Attachment E – Chinook and Sockeye Salmon Lifecyle Modeling Study Report
Attachment F – Integrated Risk Assessment of Fish Populations Study Report
Attachment G – Future Flows Study Report
Attachment H – Water Quality Assessment Study Report
Attachment I – Flow Duration Curve Change Analysis Study Report
Attachment J – Ice Processes Assessment Study Report
Attachment K – Botanical and Wetlands Survey Report
Attachment L – Caribou Population Evaluation Study Report
Attachment M – Subsistence Study Report
Attachment N – Section 106 Evaluation Report
Attachment O – Noise Study Report
Attachment P – Recreation Inventory by Season Study Report
Attachment Q – Environmental Justice Communities Study Report
Attachment R – Decision Support Tool Study Report
Attachment S – Aesthetic Study Report
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. iii December 2023
LIST OF FIGURES
Figure 1-1. Proposed Project Location............................................................................................4
Figure 1-2. Project conceptual plan.................................................................................................5
LIST OF TABLES
Table 1-1. Integrated Licensing Process (ILP) milestones for the Nuyakuk River
Hydroelectric Project (FERC 2022).........................................................................2
Table 1-2. Project Study List and Summary of Determinations by FERC (FERC 2022). ..............6
Table 2-1. Status of Project licensing studies. .................................................................................9
Table 3-1. Initial Study Report components, including study report attachment
designations and associated appendices, as applicable. .........................................12
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. iv December 2023
ACRONYMS AND ABBREVIATIONS
ADEC Alaska Department of Environmental Conservation
ADFG Alaska Department of Fish and Game
ADNR Alaska Department of Natural Resources
APE Area of Potential Effects
ARWG Aquatics Resources Working Group
BLM Bureau of Land Management
cfs cubic feet per second
Commission Federal Energy Regulatory Commission
Cooperative Nushagak Electric & Telephone Cooperative
DO dissolved oxygen
EA Environmental Assessment
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
GMU Game Management Unit
ILP Integrated Licensing Process
IRA Integrated Risk Assessment
IM Intensive Management
ISR Initial Study Report
LCM Life Cycle Model
MCH Mulchatna Caribou Herd
mg/l milligrams per liter
MW megawatt
NMFS National Marine Fisheries Service
NOI Notice of Intent
NETC Nushagak Electric & Telephone Cooperative, Inc.
PAD Pre-Application Document
PLP Preliminary Licensing Proposal
Project Nuyakuk River Hydroelectric Project (P-14873)
PSP Proposed Study Plan
RSP Revised Study Plan
S&I Survey and Inventory
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. v December 2023
SD Scoping Document
SHPO State Historic Preservation Office
SPD Study Plan Determination
TBD to be determined
USR Updated Study Report
WOTUS Waters of the United States
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 1 December 2023
1.0 INTRODUCTION
Nushagak Electric & Telephone Cooperative, Inc. (NETC or Cooperative) is filing with the
Federal Energy Regulatory Commission (FERC or Commission) an Initial Study Report (ISR)
describing the progress made during the first year of studies conducted for the Nuyakuk River
Hydroelectric Project (Project), FERC No. 14873, in accordance with 18 CFR §5.15(c)(1). The
Cooperative is seeking an original license for the proposed Project and has elected to use
FERC’s Integrated Licensing Process (ILP) as described in 18 CFR Part 5.
The Cooperative filed a Preliminary Permit Application on March 22, 2018. On June 11, 2018,
FERC issued a preliminary permit for the Project with an expiration date of June 1, 2021. The
Cooperative filed a Notice of Intent (NOI) and Pre-Application Document (PAD) on October 8,
2019, with the purpose of summarizing existing information on natural resources in the proposed
Project vicinity and describing preliminary and conceptual Project design and engineering.
FERC issued its Scoping Document 1 (SD1) to inform stakeholders about the scope of the
Environmental Assessment (EA) it intends to prepare as part of the licensing process and to seek
additional information pertinent to the analysis. The Cooperative held a Project kickoff meeting
in Anchorage, Alaska on November 18, 2019, to engage Project stakeholders and present
preliminary information about the Project. FERC held two Scoping Meetings for the Project in
Anchorage, Alaska on December 11, 2019, to discuss existing environmental conditions,
potential information needs, and resource issues.
The Cooperative filed a Proposed Study Plan (PSP) with FERC on March 20, 2020, and based on
further discussion with FERC, the Cooperative filed an updated PSP on April 16, 2020. The
Project was placed into abeyance from June 7, 2020 through March 10, 2022 due to the COVID-
19 pandemic, the need for additional public dialogue, and subsequent restrictions that prevented
requisite public meetings and site visits. On March 10, 2022, FERC issued an order accepting the
PSP and re-initiated the formal ILP. FERC’s order also provided the licensing process milestones
listed in Table 1-1.
The Cooperative filed a Revised Study Plan (RSP) on August 1, 2022, after extensive
collaboration with the Project’s Aquatics Resources Working Group (ARWG) beginning in
October 2020. Additionally, the Cooperative conducted a site visit for the ARWG and held two
public meetings in June 2022. FERC issued a Study Plan Determination (SPD) for the Project on
August 24, 2022. The SPD is discussed in Section 1.2. It is notable that some of the studies
incorporated into the RSP are the product of partnerships agreed to between the Cooperative and
some of the stakeholders.
Since the issuance of the SPD, the Cooperative has worked diligently to implement the studies as
described in the RSP. During this time, the Cooperative has continued to meet monthly with the
ARWG to provide updates regarding field study planning and implementation, preliminary study
results, and technical presentations. The Cooperative also periodically emails the Project contact
list, including over 100 stakeholders consisting of community members, Tribal governments or
corporations, and agency personnel with updates regarding the Project licensing process and
study implementation.
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 2 December 2023
This ISR documents the progress made on each of the studies required as part of the Project
licensing process. Because the ILP schedule provides two years to conduct Project studies, many
studies will require data collection and further analysis during the second study year (2024).
Thus, this ISR serves as a progress report, with additional study results and analysis to follow as
needed in the Updated Study Report (USR), to be filed with FERC no later than December 1,
2024.
Table 1-1. 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]
Comments due on Proposed
Study Plan
Licensing
Participants June 30, 2022 [90 days after PSP filed]
File Revised Proposed Study
Plan Cooperative July 30, 2022 [30 days after PSP comments filed]
Revised Proposed Study Plan
Comments Due
Licensing
Participants August 14, 2022 [15 days after Revised PSP filed]
Study Plan Determination
Issued FERC August 29, 2022 [30 days after Revised PSP filed]
Study Year 1 Cooperative May – October, 2023
File Initial Study Report 1 Cooperative December 1, 2023
Initial Study Report Meeting Cooperative December 16, 2023 [within 15 days of ISR filing]
Initial Study Report Meeting
Summary Cooperative December 31, 2023 [within 15 days of ISR meeting]
Study Year 2 Cooperative May – October, 2024
File Updated Study Report 2 Cooperative December 1, 2024
Updated Study Report Meeting Cooperative December 16, 2024 [within 15 days of ISR filing]
Updated Study Report Meeting
Summary Cooperative December 31, 2024 [within 15 days of ISR meeting]
File Preliminary Licensing
Proposal (PLP) Cooperative January 2025 [approximate; date TBD]
Comments due on PLP Licensing
Participants [90 days after PLP filed]
File License Application Cooperative December 2025 [approximate; date TBD]
1 On February 6, 2023, the Cooperative filed an extension of time request to modify the Initial Study Report (ISR) and Updated
Study Report (USR) filing deadlines to December 1, 2023 and December 1, 2024, respectively, to allow for the completion of
field study seasons prior to study reporting each year. FERC approved this request on February 15, 2023.
2 See footnote 1 above with respect to the December 1, 2024 USR filing extension.
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 3 December 2023
1.1 Project Description
The proposed Project would be located in southwest Alaska on the Nuyakuk River
approximately 60 miles north of Dillingham, AK (pop. 2,364) near Tikchik Lake in the
watershed that drains the eastern side of the Wood River Mountains (Figure 1-1). The Project
site is inside the current Wood-Tikchik State Park boundary by approximately 4 miles. From the
Project site, the Nuyakuk River runs approximately 40 miles before converging with the
Nushagak River, which continues to Bristol Bay.
The proposed Project would be a new 10-12 megawatt (MW) conventional hydropower project
consisting of an intake structure, power conduit, powerhouse forebay, powerhouse, and tailrace
channel approximately 4.5 miles downstream of the Tikchik Lake outlet above a natural Falls on
the Nuyakuk River (Figure 1-2). The Project’s river intake would divert water from the Nuyakuk
River, above Nuyakuk Falls to a powerhouse located near the base of Nuyakuk Falls. From the
Project site, the Nuyakuk River runs approximately 40 miles before confluencing with the
Nushagak River, which continues to Bristol Bay.
Power from the Project would be available to the customers of the Cooperative and potentially
other areas in the region. The renewable power provided by the Project would represent a
significant improvement in the current distribution system and minimize the reliance of local
communities on fossil fuels as their primary source of electricity. Currently, the population that
would be served by this Project relies wholly on diesel generation, which is barged upstream
through the Nushagak and Kvichak River drainages to requisite locations. The reduction of water
transport of fuels and storage quantity will reduce the potential for negative environmental
impacts due to spills. The primary industry in the Project service area is related to commercial
harvesting and processing of salmon. The long-term demand for more reliable, efficient, and
cost-effective power along with the likely limited resource impacts makes this Project a highly
viable opportunity.
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 4 December 2023
Figure 1-1. Proposed Project Location.
Nuyakuk River Hydroelectric ProjectFERC No. 14873 Initial Study Report Nushagak Cooperative, Inc. 5 December 2023Figure 1-2. Project conceptual plan
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 6 December 2023
1.2 Study Plan Determination Overview
In the Project’s SPD, FERC approved 14 of the 18 studies proposed by the Cooperative, 2 were
approved with staff recommended modifications, and 2 studies were deemed not required. In
addition, FERC required that the Cooperative conduct one additional study not included in the
RSP. Table 1-2 lists the studies according to the categories described above. The two studies not
required by FERC (Study 7 and Study 9) are still being executed per an agreement by the
Cooperative and the National Marine Fisheries Service (NMFS).
Table 1-2. Project Study List and Summary of Determinations by FERC (FERC 2022).
Study Proposed or
Requested By
Approved
by FERC
Approved by
FERC with
Modifications
Not
Required
1. Characterization of Fish
Community and Behavior near the
Project Intake
Cooperative X
2. Nuyakuk Falls Fish Passage
Study Cooperative X
3. Fish Entrainment and
Impingement Study Cooperative X
4. Assessment of False Attraction
to the Tailrace Barrier Cooperative X
5. Chinook and Salmon Lifecycle
Modeling Cooperative X
6. Integrated Risk Assessment of
Fish Populations Cooperative X
7. Future Flows Study
Cooperative;
NMFS X
8. Water Quality Assessment Cooperative X
9. Flow Duration Curve Change
Analysis Study
Cooperative;
NMFS X
10. Ice Processes Assessment Cooperative X
11. Botanical and Wetlands Survey Cooperative X
12. Caribou Population Evaluation Cooperative X
13. Subsistence Study Cooperative X
14. Section 106 Evaluation Cooperative X
15. Noise Study Cooperative X
16. Recreation Inventory by
Season Cooperative X
17. Environmental Justice
Communities Cooperative X
18. Decision Support Tool Cooperative X
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 7 December 2023
Study Proposed or
Requested By
Approved
by FERC
Approved by
FERC with
Modifications
Not
Required
19. Aesthetic Study FERC X
1.3 Initial Study Report Meeting
In accordance with 18 CFR §5.15(c)(2), the Cooperative will hold two ISR meetings in
Dillingham, Alaska on Tuesday, December 5, 2023, from 1-4pm and 6-9pm Alaska Time. The
Cooperative is holding one meeting during typical business hours and a second meeting in the
evening to accommodate attendee’s schedules and maximize attendance. Both meetings will be
held in person, with the option to join virtually for anyone that is unable to or prefers not to meet
in person. The purpose of the ISR meetings will be to present the results of the first study season,
discuss the status of ongoing studies, and answer any questions regarding the studies or reports
prior to stakeholder and public review. In accordance with the requirements of 18 CFR
§5.15(c)(3), the Cooperative will file a summary of the ISR meetings with FERC within 15 days
following the meetings. If any participants or FERC staff wish to modify ongoing studies,
propose new studies, or have disagreements with the Cooperative’s meeting summary, those
must be filed with FERC within 30 days following the meeting summary filing in accordance
with 18 CFR §5.15(c)(4).
Both meetings will be held at:
Nushagak Cooperative Boardroom
557 Kenny Wren Rd
Dillingham, AK 99576
The meetings can be attended virtually using the information below:
Daytime Meeting: December 5, 2023, 1-4pm Alaska Standard Time
Click here to join the meeting
Meeting ID: 243 836 312 759
Passcode: nWAgt6
Or call in (audio only)
+1 929-346-7316,,526876035# United States
Phone Conference ID: 526 876 035#
Evening Meeting: December 5, 2023, 6-9pm Alaska Standard Time
Click here to join the meeting
Meeting ID: 291 897 674 935
Passcode: 3yXhTQ
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 8 December 2023
Or call in (audio only)
+1 929-346-7316,,217783922# United States
Phone Conference ID: 217 783 922#
Meeting information will also be posted in public locations in Dillingham, Koliganek, New
Stuyahok, Ekwok, and Levelock, emailed to the Project stakeholder contact list, and posted on
the Cooperative’s Project website (www.nuyakukhydro.com).
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 9 December 2023
2.0 CURRENT STATUS OF PROJECT LICENSING STUDIES
2.1 Study Status
The Cooperative initiated the majority of the study program in 2023. Three studies were
completed in 2023, including the Botanical and Wetlands Survey, Caribou Population
Evaluation, and Noise Study. Eleven studies were initiated in 2023 and will be completed in
2024, and the remaining Five studies will be conducted during the 2024 study season. Additional
details about each of the studies listed in Table 2-1 are provided in Section 4.0 (Study Report
Summaries) and in Attachments A through S of this ISR, which contain detailed study reports.
Table 2-1. Status of Project licensing studies.
Study Study Completed
in 2023
Study Underway (to
be Completed in 2024)
Study to be
Conducted in 2024
1. Characterization of Fish Community
and Behavior near the Project Intake X
2. Nuyakuk Falls Fish Passage Study X
3. Fish Entrainment and Impingement
Study X
4. Assessment of False Attraction to
the Tailrace Barrier X
5. Chinook and Salmon Lifecycle
Modeling X
6. Integrated Risk Assessment of Fish
Populations X
7. Future Flows Study X
8. Water Quality Assessment X
9. Flow Duration Curve Change
Analysis Study X
10. Ice Processes Assessment X
11. Botanical and Wetlands Survey X
12. Caribou Population Evaluation X
13. Subsistence Study X
14. Section 106 Evaluation X
15. Noise Study X
16. Recreation Inventory by Season X
17. Environmental Justice Communities X
18. Decision Support Tool X
19. Aesthetic Study X
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 10 December 2023
2.2 Field Camp and Safety Program
The remote location of the Project site necessitated a significant amount of planning, preparation,
and logistical considerations. The Cooperative obtained the requisite Special Use Permit from
the Alaska Department of Natural Resources (ADNR) to establish a field camp at the Project
site, which is located in Wood Tikchik State Park. The field camp consisted of several small,
easily removable cabin structures, an incinerator toilet, and boats stationed both above and below
Nuyakuk Falls. Due to the potential danger of working in such a remote site and from wildlife, a
Camp Manager was stationed at the field camp during the entire field season to assist study
teams and provide protection from bears, as needed. In addition to satellite phones and inReach
capabilities, the Cooperative established StarLink (satellite) internet access at the site for safety
and to facilitate work and personal communication for field workers. The Cooperative
implemented a detailed safety plan that involved nightly communication check-ins between the
Camp Manager and offsite Project staff that have resources to initiate search and rescue or other
safety support measures, as needed. The 2023 field season was successful both in terms of data
collection and with respect to the establishment of safe and comfortable working conditions for
field team members. No safety incidents occurred during 2023, and the Cooperative plans to
implement consistent logistics and safety protocols during the 2024 field season.
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 11 December 2023
3.0 INITIAL STUDY REPORT COMPONENTS
This ISR contains progress reports for each of the Project licensing studies included in FERC’s
SPD. Table 3-1 lists all study reports provided as attachments to this ISR. For consistency and to
ensure compliance with FERC’s regulations in 18 CFR §5.15(c)(1), each study report attachment
includes the follow sections, with study-specific information:
1.0 Study Plan Introduction: a summary of the study plan that was approved by FERC.
2.0 Study Goals and Objectives: a summary of the study goals and objectives based on
study plan that was approved by FERC.
3.0 Study Area: a description of the geographic extent of the study area and specific sites
utilized within the study area, if applicable.
4.0 Methodology: a description of the methods used to conduct the study.
5.0 Results: a description of the results and/or data collected during study plan
implementation.
6.0 Discussion and Findings: discussion of study results and any conclusions or findings
based on study results.
7.0 Study Variances and Modifications: a description of any modifications or variances
from the study plan approved by FERC, with a rationale for any deviances from the study
plan.
8.0 Study Status and Schedule: the status of the study at the time of the ISR filing, and
the schedule for study completion, if not already completed.
9.0 Study-Specific Consultation: a description of any consultation that was conducted
specific to the study during study plan implementation.
10.0 References: a list of references cited in the study report.
In the event that a study was not initiated during 2023 (Table 2-1), a study report is still provided
with information regarding plans for study implementation in 2024 and the schedule for study
completion.
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 12 December 2023
Table 3-1. Initial Study Report components, including study report attachment designations and
associated appendices, as applicable.
Attachment Study Report Study Report Appendices (if applicable)
A Characterization of Fish Community
and Behavior near the Project Intake
Appendix A-1: Preliminary Nuyakuk River
Radio Telemetry Array Deployment and
Performance Information
Appendix A-2: Preliminary Nuyakuk River
Sonar Analysis of Smolt Outmigration
B Nuyakuk Falls Fish Passage Study
Appendix B-1: 2023 Topobathymetric Lidar
Technical Data Report
C Fish Entrainment and Impingement
Study n/a
D Assessment of False Attraction to the
Tailrace Barrier n/a
E Chinook and Salmon Lifecycle Modeling n/a
F Integrated Risk Assessment of Fish
Populations n/a
G Future Flows Study n/a
H Water Quality Assessment n/a
I Flow Duration Curve Change Analysis
Study n/a
J Ice Processes Assessment n/a
K Botanical and Wetlands Survey
Appendix K-1: Botanical and Wetland Survey
Maps
Appendix K-2: Preliminary Wetland
Delineation Report
L Caribou Population Evaluation n/a
M Subsistence Study n/a
N Section 106 Evaluation [Note: Complete
Study Report filed as PRIVILEGED] n/a
O Noise Study Appendix O-1: Sound Level Measurement
Result Graphs
P Recreation Inventory by Season
Appendix P-1: Recreation Study Commercial
Operator Data Form
Appendix P-2: Recreation Field Study
Observations
Appendix P-3: Project Site Recreation Field
Survey
Q Environmental Justice Communities n/a
R Decision Support Tool n/a
S Aesthetic Study n/a
Nuyakuk River Hydroelectric Project
FERC No. 14873 Initial Study Report
Nushagak Cooperative, Inc. 13 December 2023
4.0 STUDY REPORT SUMMARIES
Sections 4.1 through 4.19 provide a high-level summary of each study report (Attachments A
through S to this ISR).
4.1 Characterization of Fish Community Behavior Near the Project Intake
(Attachment A)
The primary goal of this study is to determine the seasonal timing, species composition, relative
abundance, habitat use, and migratory patterns of fishes within the Project Area that represents a
baseline of conditions. To address this goal in Year 1 (2023), fish sampling was completed using
various netting, trapping, and observational methods to develop a species-and-life-history stage-
specific periodicity table of fish use in the Project Area. Fish sampling occurred throughout the
ice-free period beginning with sampling of out-migration salmon smolts in May and continuing
through summer sampling of juvenile and adult resident fishes and migrating anadromous
salmon. The Year 1 field component of this study will finish in the winter of 2024 with tracking
of radio-tagged Arctic Grayling upstream and downstream of the Falls.
This study will continue with another year of sampling and further analysis of field data in 2024
to provide additional data on the periodicity of species and habitat use in the Project Area. This
ISR provides a description of fish species and life stages encountered during Year 1 in Study
Area zones above, within, and below, the Falls Reach. Species encountered in 2023 including
salmon (Chinook, Sockeye, Coho, Pink, and chum), trout (Rainbow Trout, Lake Trout), Arctic
Grayling, Northern Pike, Whitefish (humpback, pygmy), Arctic Lamprey, Burbot, sticklebacks
(3-spine, 9-spine), and various sculpins.
Two additional efforts were completed in Year 1 including the implementation of a
hydroacoustic array to monitor downstream migrating juveniles and radio telemetry studies to
evaluate passage behavior and success of upstream migrating adult salmon as well as
documenting Arctic Grayling habitat use in the Project Area. All three studies were successfully
implemented during Year 1, and data analysis for both studies is currently in progress and will
inform not only the periodicity chart but also the modeling efforts described in Attachment B.
4.2 Nuyakuk Falls Fish Passage Study (Attachment B)
The primary goal of this study is to evaluate how potential Project-related flow changes may
impact fish habitat and passage conditions in the Falls Reach. While this study has various
components, the focus of Year 1 work included field collection of bathymetric data and water
surface elevation data, initial development and calibration of a two-dimensional (2D) hydraulic
model for the Project Area, and development of an Agent-Based Model (ABM) that will be used
to predict fish passage behavior under varying flow conditions. Year 1 also included
coordination with the Aquatic Resources Working Group (ARWG) and across study teams for
model integration.
Many aspects of this study are ongoing through the fall and winter of 2023, as necessary inputs
to both the 2D and ABM models require the fully analyzed fisheries field data (i.e., periodicity,
upstream migration, downstream migration) and post-processed imagery data (i.e., Light
Detection and Ranging). At this time, both models are under development with input and
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corroboration from the ARWG. The schedule for future reporting on model results is described
in Attachment B.
4.3 Fish Entrainment and Impingement Study (Attachment C)
The primary goal of this study is to understand the potential for the Project to entrain fishes that
are in the vicinity of the intake and to minimize the level of potential injury and mortality that
might be associated with entrainment or passage through the Falls Reach. In Year 1, literature
review and data collection to inform this study occurred under Fish Community and Fish Passage
studies. For example, results from hydroacoustic monitoring of the downstream timing and
distribution of migrating salmon smolts (Attachment A) will inform the periodicity of potential
entrainment risk to juvenile fishes. Additional supporting data is forthcoming during winter 2023
and study implementation is scheduled for Year 2.
4.4 Assessment of False Attraction to the Tailrace Fish Barrier (Attachment D)
The primary goal of this study is to inform tailrace design and Project outflow options to
minimize potential impacts to upstream migrating fishes. In Year 1, literature review and data
collection to inform this study occurred under Fish Community and Fish Passage studies. For
example, results from the radio telemetry study monitoring the passage behavior and timing of
adult salmon transiting the Falls Reach (Attachment A) will inform the assessment of the
potential risk of false attraction of adult salmonids staging in the Project Area during their
upstream migration. Additional supporting data is forthcoming during winter 2023 and study
implementation is scheduled for Year 2.
4.5 Chinook and Sockeye Salmon Lifecyle Modeling (Attachment E)
The primary goal of this study is to develop a Life Cycle Model (LCM) for Sockeye and
Chinook salmon on the Nuyakuk River that includes important life stages and is capable of
reflecting both direct and indirect Project effects. In Year 1, literature review, study data from
other areas and prior studies were utilized to build a straw man LCM for Sockeye Salmon. Data
collection from 2023 and 2024 associated with the Fish Community and Fish Passage studies
will also be utilized to inform LCM development.
4.6 Integrated Risk Assessment of Fish Populations (Attachment F)
The overarching goal of this study is to provide a framework for quantifying and/or qualifying
the relative risk of Project-related impacts to the fish communities over the course of its lifecycle
and over the life of the Project. This study will address target fish species including Sockeye,
Chinook, and other Pacific salmon along with selected native migratory and resident fish species
that use habitats within the Project Area.
The Integrated Risk Assessment (IRA) will integrate potential population responses to a range of
environmental and Project conditions or scenarios, such that we can evaluate the likelihood of
certain benefits and costs associated with the Project. This assessment will allow the
Cooperative, agencies, and stakeholders to decide what impacts (positive and negative) to the
populations can be expected and which are acceptable. The study will rely on site-specific data
collected during the Project study program along with knowledge from available experts and
local empirical sources. The development of the IRA tool was initiated in Year 1 with a proof-
of-concept assessment for Sockeye Salmon. Initial steps that are ongoing include site-specific
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data collection, identifying management objectives, researching and selecting appropriate risk
sources and risk elements that are relevant to the Nuyakuk River fish populations, and species-
specific management objectives. An IRA meeting to define Sockeye Salmon management
objectives with the ARWG occurred on November 8, 2023. The Cooperative has scheduled a
workshop for the ARWG to review and refine a straw-man assessment on December 6, 2023.
4.7 Future Flows Study (Attachment G)
To realize the combined potential benefits of the Project it is necessary to understand the
consistent, projected changes in the nature, amount, and timing of precipitation and how that will
affect flow in the Nuyakuk River. Under this study, existing peer-reviewed climate model
predictions will be used to model future discharges for the Nuyakuk River, in accordance with
peer-reviewed published methods and generally accepted practice as described below. This
information will inform the development of license articles guiding operation and maintenance,
including mitigation measures, as well as the development of a climate-resilient Project design.
In Year 1, a MIKESHE/MIKE Hydro model was developed for the upper Nuyakuk River
watershed using climate projections from 5 different climate models and one climate ensemble
mean. Changes in snow and rain precipitation events resulted mean monthly projections for both
a mid- and late-century climate scenario. Overall, the hydrograph is projected to flatten, with
higher winter flows, lower spring and early summer peak flows and similar late summer flows as
compared to existing conditions. This pattern is projected to be more extreme for the late-century
scenario.
The results of the future flow model completed in 2023 will inform Year 2 tasks for this and
other studies. In 2024, efforts will be focused on understanding how the flow changes may
affect: water temperatures, the potential future timing of salmon runs, fish passage through the
Falls, ice processes, fish entrainment and impingement as well as project design and operation
including turbine sizing and energy production.
4.8 Water Quality Assessment (Attachment H)
The primary goal of this study was to determine how water temperatures and dissolved oxygen
(DO) concentrations compare to Alaska Department of Environmental Conservation (ADEC)
standards for fish and wildlife (designated use criteria [C]). In addition, DO was qualitatively
assessed to determine if Nuyakuk Falls serves as a critical location for DO recharge. Continuous
monitoring from two periods (July 24, 2018 - January 4, 2021; and June 7, 2022 -September 12,
2022) reveal that maximum daily temperatures briefly exceed ADEC’s 20°C criteria in July of
2019 at the Project site. Supplemental temperature criteria for spawning/egg & fry incubation
(13°C) and migration routes/rearing areas (15°C) can be exceeded from early-June through mid-
September. DO concentrations met ADEC’s 7 milligrams per liter (mg/l) criteria above and
below the Falls with values ranging from 8.9 mg/l to 13.0 mg/l. Although diurnal DO patterns
were observed upstream of the Falls in comparison to the downstream station, daily average DO
concentrations at the two locations agree within 0.5 mg/l. These similarities indicate adequate
DO levels above the Falls with limited to no increases in DO below the Falls. Year 2 field
studies (2024) for DO will focus on monitoring during Sockeye staging at the base of the Falls to
assess DO depletion. Additional water quality data from Year 2will include water temperature
monitoring results through September of 2024.
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4.9 Flow Duration Curve Change Analysis Study (Attachment I)
The primary goal of this study is to evaluate changes in the flow duration curve for the Nuyakuk
River that have happened during the United States Geological Survey (USGS) 15302000 gage
record that spans 70 years (1953- 2023). Although the flow duration curve assessment is
primarily a desktop exercise, a Project site stream gage was installed in June of 2022 to
accurately calculate flow volumes at the proposed Project site. During Year 1 of the study
program, a rating equation was developed (n=5) and validated (n=2) by a total of 7 discharge
measurements collected from May 12, 2023-August 24, 2023. The Project stream gage provided
an excellent correlation to USGS gaging station 15302000 during periods of ice-free operation
(R2 of 0.9969). The record from the Project gage also showed flow increases (i.e., accretion)
ranging from 97.1 cubic feet per second (cfs) to 1650 cfs with an average of 509 cfs over the
June 2022-August 2023 monitoring period. In Year 2 of the study program, stream gage
operation will continue through September of 2024 with particular emphasis on gaging data over
the winter of 2023-2024. Statistical assessment to determine the stationary of flow duration
curves will also take place in Year 2 of the study program and will be summarized as part of the
USR in December of 2024.
4.10 Ice Processes Assessment (Attachment J)
The primary goal of this study is to utilize satellite imagery, data supplemented by site-specific
photos and/or video, and information from other hydro projects to gain a better understanding of
both existing ice formation processes and the potential for localized modifications to these
processes as a result of Project operations. Imagery at the Project site was unsuccessful in Year
1 of the study program due to equipment issues. An alternative method to collect site-specific
imagery will be discussed at upcoming Aquatics Resources Working Group (ARWG) meetings
and finalized at the Initial Study Report (ISR) meeting in mid-December of 2023. In Year 2
(2024), alternative measures will be employed based on imagery results from remote cameras
scheduled to be downloaded in December of 2023. Year 2 will also include ongoing desktop
efforts to review satellite imagery and gather information from nearby hydroelectric facilities
(e.g.Tazimina Falls Project; P-11316). These Year 2 findings will be synthesized and
summarized as part of the USR in December of 2024.
4.11 Botanical and Wetlands Survey (Attachment K)
The study gathered baseline botanical and wetland data, including surveying vegetation types,
wetlands, Bureau of Land Management (BLM) Special Status plant species, and non-native plant
species in the proposed Project boundary. The study consisted of desktop vegetation and wetland
analysis of the Project boundary and field-based data collection in the Project facility study area.
Vegetation and wetland habitat were classified and mapped to support further Project planning,
applications for appropriate authorizations, and avoidance or mitigation of potential negative
Project impacts.
Project impacts would result from the construction of Project facility and transmission lines. The
Project facility study area is predominantly uplands (92.72 acres) with 4.87 acres of wetlands.
Layout of the Project facilities would be placed to avoid impacts to wetlands and Waters of the
United States (WOTUS) to the greatest extent practicable, but some unavoidable impacts could
be anticipated at either end of the Project facility’s intake tunnel. The proposed transmission line
infrastructure would include towers or poles spaced at around 200 to 800 feet along the
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transmission line route, for a total of approximately 1,780 towers or poles. Each tower or pole
would have a relatively small footprint (~0.4 acre) in relation to the total Project area of 1,227
acres. Project area vegetation, with the exception of limited rare plant sightings, is typical for the
region and likely provides no special habitat. No invasive species were found within the Project
facility study area.
4.12 Caribou Population Evaluation (Attachment L)
. The study objectives were to evaluate the impacts from the proposed Project on the Mulchatna
Caribou Herd (MCH) within Game Management Units (GMUs) 17B, 17C and 9B. The impacts
analysis incorporated a literature review, data extracted from Alaska Department of Fish and
Game (ADFG) Survey & Inventory (S&I) reports, and data provided by ADFG illustrating
historical and seasonal distribution (2020-2022) of the MCH.
State management objectives are to maintain a population of 30,000 – 80,000 individuals with a
bull-to-cow ratio of 35:100 and a calf-to-cow ratio of 30:100 (Barten and Watine 2020; ADFG
2023). Currently, the MCH does not meet the population management objective of 30,000-
80,000 individuals. In 2022, the calf-to-cow ratios were 26:100 and 31:100 for the west and east
segments, respectively (ADFG 2023). The bull-to-cow ratios were 32:100 and 44:100 for the
west and east segments, respectively (ADFG 2023).
Potential impacts on the MCH associated with the proposed transmission line may include: 1)
impacts on habitat, 2) behavioral and physiological responses, 3) increased predation, and 4)
increased anthropogenic activity. Direct habitat loss from the proposed Project footprint would
not likely have a substantial impact on the MCH because the Project footprint area is relatively
small compared to the overall range of the MCH. Short-term increases in anthropogenic activity
is anticipated during construction and may increase over the long-term depending on
accessibility of the transmission line corridor. In either scenario, short or long-term increases in
anthropogenic activity may result in caribou avoidance of the area.
4.13 Subsistence Study (Attachment M)
Based upon overall study planning and study-specific contractor availability, the Subsistence
Study, as specified in the RSP, will be implemented in 2024. The data will be analyzed and
reported on in the USR, along with an assessment of potential impacts associated with Project
development and operations.
4.14 Section 106 Evaluation (Attachment N)
Cultural Resource Consultants LLC (CRC) conducted an archaeological survey of the proposed
Nuyakuk Hydroelectric Project facilities area to identify any historic properties that could be
eligible for the National Register of Historic Places (National Register) and to assess the
potential effects of the Project on any such properties. Using topography, aerial imagery,
previously reported sites, and ethnographic and historic data, areas of higher probability for
cultural resources were identified. Archaeological investigations included pedestrian survey and
shovel testing within the roughly 90-acre proposed Area of Potential Effects (APE) that included
an intake structure, powerhouse facility, airstrip, access road, cabins, and other structures.
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CRC’s survey and testing of the proposed Project facilities area in July of 2023 identified a
portage trail (DIL-00272), a subsurface archaeological site bisected by the trail (DIL-00271), and
two sites with surface features that may be cache pits (DIL-00270 and DIL-00273). DIL-00270
and DIL-00273 were not recommended as eligible for the National Register of Historic Places,
while the Nuyakuk Falls Portage Trail (DIL-00272) and archaeological site DIL-00271 are likely
significant enough to be eligible.
The archaeological study of the Project’s intake structure and associated facilities at Nuyakuk
Falls is complete. Constructing the Project facilities as currently proposed would not constitute
an adverse effect on either the portage trail (DIL-00272) or the associated archaeological site
(DIL-00271). Consultation meetings with Tribal governments, Native organizations, the State
Historic Preservation Office (SHPO), and other interested parties will occur during the winter of
2023/2024 to discuss field findings and to expand the scope of existing information to include
intangible cultural resources such as traditional cultural properties and cultural landscapes.
4.15 Noise Study (Attachment O)
A noise study was performed to assess the existing sound levels in the Project area and predict
future sound level impacts that would occur during short-term construction and long-term
operations at areas of interest surrounding the proposed Project location. The noise study
consisted of ambient sound level measurements at four locations surrounding the proposed
Project location, including the closest occupied structure, the Royal Coachman Lodge. The noise
study also included noise modeling to predict sound levels during general construction,
construction blasting, general operations, and aircraft operations associated with the proposed
Project.
The sound level impacts of the Project activities are not expected to be significant. The
predicted sound levels from construction and operations are significantly lower than the FERC
guidelines for each activity. General temporary construction sounds are expected to be
imperceptible at about one mile from the site. Guidelines and criteria are provided in the study
for the potential of construction blasting activities to ensure that they do not cause a significant
impact at nearby sensitive receptors. Sound levels during Project operation will not be
perceptible at the Royal Coachman Lodge and are expected to be barely perceptible at about
2,500 feet from the Powerhouse. Sound from aircraft activity associated with operation of the
proposed Project at the Royal Coachman Lodge will be much quieter than current aircraft
activities at that location and are expected to be compatible with recreational land uses and the
existing acoustical environment.
4.16 Recreation Inventory by Season (Attachment P)
The purpose of the recreation study is to inventory and quantify the type and volume of
recreational use occurring during each season in the vicinity surrounding the proposed Project
facilities on the Nuyakuk River, from approximately ½ mile upstream of the proposed Project
intake to 1 mile downstream of the proposed Project tailrace. Study efforts in 2023 focused on
documenting summer use of the area. Two staff conducted six days of onsite field observations
from July 14-19, 2023. Intercept surveys were distributed to recreating visitors to document their
recreation activities and experiences.
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Observed visitation consisted exclusively of guided, private fly-fishing visits operated by
Tikchik Narrows Lodge and Royal Coachman Lodge. All recreation activity was concentrated to
the river shorelines just below the lower Falls. Access was by plane then motorboat below the
Falls, or by motorboat and portage trail above the Falls. Fishing groups were observed five of six
days and are believed to be a nearly-daily occurrence during the lodges’ open seasons. A total of
38 visits to the area were observed (average of 6 persons per day) with 27 assumed to be unique
visitor clients. Eight visitors responded to intercept surveys. More study efforts are planned and
necessary to ascertain local use, winter use, and gather data from park staff and commercial
operators to expand on summer field observations. Key impacts to consider will include visual
resources, access to the portage trail, and shoreline layout that could affect fishing spot access on
the south shore.
4.17 Environmental Justice Communities (Attachment Q)
In accordance with the issuance of FERC’s Equity Action Plan (FERC 2022), the Cooperative
proposed to conduct an Environmental Justice (EJ) Study to determine if development of the
proposed Project would affect populations that identify as environmental justice communities.
Project construction, operation, and maintenance has the potential to affect human health or the
living conditions in environmental justice communities. Examples of resource impacts may
include, but are not necessarily limited to, project-related effects on: groundwater or other
drinking water sources; subsistence fishing, hunting, or plant gathering; access for recreation;
housing or industries of importance to environmental justice communities; and construction-or
operation-related air quality, noise, and traffic.
Initial datasets from the American Community Survey have been obtained from publicly
available sources but have not yet been compiled and analyzed. Additional data collection,
including identification of non-English speaking groups and sensitive receptor locations has not
yet been initiated. The study will be implemented as described in FERC’s SPD with results being
reported in the Project’s USR in December 2024.
4.18 Decision Support Tool (Attachment R)
The Cooperative elected to develop an economic analysis tool that will assist in evaluating the
potential economic impact of the Project (positive and negative) over the duration of its
operations. The economic analysis tool, hereafter referred to as the economic Decision Support
Tool or eDST, considers both: 1) economic impact of developing the run-of-river hydropower
project as well as the impact on the Sockeye and Chinook fisheries, and 2) an electricity-based
rate model to explore cost differentials between current diesel generation and with the run-of-
river with diesel backup approach. The eDST will accept information from the river flow/climate
model in terms of the impact over the 50-year life of the run-of-river hydro generation system,
the powerhouse model, and the aquatic fisheries lifecycle model to capture the economic impact
from changes in sport and commercial fishing.
At the time of the ISR filing, no results from the eDST are available as no new input values have
been provided for use in the eDST. Continued integration with the other relevant models will
take place during the remainder of 2023 and the 2024 study seasons. Results and analysis will be
reported on in the USR.
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4.19 Aesthetic Study (Attachment S)
Based upon overall study planning and study-specific contractor availability, the Aesthetic
Study, as requested by FERC in their Study Plan Determination, will be implemented in 2024.
The data and renderings will be analyzed and reported in the USR, along with an assessment of
potential impacts associated with Project development and operations.
Nuyakuk River Hydroelectric Project
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5.0 REFERENCES
Alaska Department of Fish and Game (ADFG). 2023. Annual Report to the Alaska Board of
Game on Intensive Management of Caribous with Wolf Predation Control in Game
Management Units 9B. 17B&C, and 19A&C, the Mulchatna Caribou Herd. Division of
Wildlife Conservation. February 2023. ADFG. 2023c. Annual Report to the Alaska
Board of Game on Intensive Management of Caribous with Wolf Predation Control in
Game Management Units 9B. 17B&C, and 19A&C, the Mulchatna Caribou Herd.
Division of Wildlife Conservation. February 2023.
<https://www.adfg.alaska.gov/static/applications/web/nocache/research/programs/intensi
vemanagement/pdfs/2023_mulchatna_intensive_management_annual_report.pdfC35CF7
61C6A6807EAAD78B8167B662D2/2023_mulchatna_intensive_management_annual_re
port.pdf>. Accessed August 25, 2023.Accessed August 25, 2023.
Barten, N. L., and Watine, L. N. 2020. Caribou Management Report and Plan, Game
Management Units 9A, 9B, 9C, 17A, 17B, 17C, 18, 19A, 19B: Mulchatna Caribou Herd.
Alaska Department of Fish and Game, Division of Wildlife Conservation.
ADF&G/DWC/SMR&P-2020-2.
Federal Energy Regulatory Commission (FERC). 2022. Study Plan Determination for the
Nuyakuk River Hydroelectric Project (P-14873). Issued August 24, 2022.
Fletcher, W.R.J. 2015. Review and refinement of an existing qualitative risk assessment method
for application within an ecosystem-based management framework. ICES Journal of
Marine Science, 72(3), 1043-1056.
INITIAL STUDY REPORT
ATTACHMENT A: CHARACTERIZATION OF FISH COMMUNITY BEHAVIOR NEAR
THE PROJECT INTAKE
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 INTRODUCTION.............................................................................................................. 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 3
4.1 Literature Review.................................................................................................... 3
4.2 Fish Sampling Methods........................................................................................... 5
4.2.1 Seining........................................................................................................ 5
4.2.2 Minnow Trapping ....................................................................................... 5
4.2.3 Gill/Trammel Netting .................................................................................. 5
4.2.4 Visual Observations .................................................................................... 6
4.2.5 Angling ....................................................................................................... 7
4.3 Fish Community...................................................................................................... 7
4.4 Downstream Salmonid Smolt Migration ................................................................ 8
4.4.1 Equipment Deployment .............................................................................. 8
4.4.2 Sonar Operations....................................................................................... 10
4.4.3 Data Analysis ............................................................................................ 11
4.5 Upstream Adult Salmon Migration/Radio Telemetry........................................... 12
4.6 Timing, Distribution and Relative Abundance of Piscivores................................. 14
5.0 RESULTS ......................................................................................................................... 16
5.1 Fish Community.................................................................................................... 16
5.2 Downstream Smolt Migration/Hydro-acoustics..................................................... 18
5.2.1 Hydroacoustic Data Analysis.................................................................... 19
5.3 Upstream Adult Salmon Migration/Radio Telemetry Study ................................ 23
5.3.1 Radio Telemetry Study ............................................................................. 23
5.3.2 Visual Observation.................................................................................... 25
5.3.3 Movement Patterns of Piscivores.............................................................. 26
6.0 DISCUSSION AND FINDINGS...................................................................................... 27
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 27
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 27
8.1 Fish Community.................................................................................................... 27
8.2 Downstream Smolt Migration Behavior............................................................... 27
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8.3 Piscivores.............................................................................................................. 28
9.0 STUDY-SPECIFIC CONSULTATION........................................................................... 28
9.1 Consultation Summary.......................................................................................... 28
9.2 Report Delivery Schedule..................................................................................... 29
10.0 REFERENCES ................................................................................................................. 29
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LIST OF FIGURES
Figure 3-1. Fish Community Study Area showing Zone 1 (Downstream of Falls), Zone 2
(Falls Reach), and Zone 3 (Upstream of Falls)........................................................3
Figure 4-1. Preliminary lifestage periodicity for a sample of the fish species utilizing the
Nuyakuk River, Alaska. Subject to revision. ...........................................................4
Figure 4-2. Hydroacoustic array configuration showing up-looking 6-degree beam sonar
transducers (T1-T8) and the side-looking 2-degree beam.......................................9
Figure 4-3. Hydroacoustic components prior to installation on May 12, 2023. Bright green
data-cable was mated to stainless cables. Sonar heads were bolted into
custom made aluminum sleds weighted with recycled free weights.....................10
Figure 4-4. Radio telemetry array deployment locations. Each passage array includes one
antenna while the Zone 2 Route Selection Array includes eight antennas
deployed on both banks of the river. Inset shows detail of Route Selection
Array (Zone 2) placement. .....................................................................................13
Figure 4-5. Tagging detail for adult Sockeye. ...............................................................................14
Figure 4-6. Detail showing closed incision with interrupted sutures and trailing radio
transmitter antenna on an Arctic Grayling captured at the outfall of the Falls
Reach in July 2023. ................................................................................................15
Figure 5-1. Fish community data collection period over the Year 1, 2023 season........................17
Figure 5-2. 2023 Downstream smolt outmigration monitoring hydroacoustic sonar
installation including up-looking (green dots) and side scan (green triangle)
sonar and control tent. ............................................................................................19
Figure 5-3. Screening results May 25-June 21, 2023. Each cell represents the area
backscattering coefficient from up-looking transducer T4 (1 column per
hour, 1 row per 0.2 m depth increment, top to bottom). Color ramp maps
backscatter values from low (blue) to high (red). May 29-June 3, 2023 and
June 20, 2023 are good examples of backscatter patterns indicative of smolt
passage events: several contiguous hours of high backscatter values mostly
in the top third of the water column, gradually ramping up and down. .................21
Figure 5-4. Side-looking echogram interpretation. Concept illustration of smolt school
movement over time showing scale of schools and school movement. Here,
a 5-minute-long echogram excerpt has been draped over an approximate
longitudinal distance of 300 m, the distance smolts would cover at a speed
of 1 meter per second.............................................................................................22
Figure 5-5. Fork length distribution of adult Sockeye Salmon tagged during radio telemetry
study to address upstream migration timing, success, and behavior at the
Nuyakuk River Falls. .............................................................................................23
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Figure 5-6. Example results of radio telemetry array range and detection efficiency testing.
The receiver (indicated in red) successfully detected sample tags with ID 14
(black squares) and 411 (white squares). ...............................................................24
Figure 5-7. Example visual observation of an adult Sockeye Salmon passage attempt at the
far left bank of the Falls Reach (left panel), and the location where the
passage attempt took place (right panel). ...............................................................25
Figure 5-8. Drone footage showing where adult Sockeye were staging immediately below
the right-bank Falls chute at the downstream Nuyakuk Falls boat landing.
July 2023. Photo M. Nobles. ..................................................................................26
Figure 5-9. Size distribution (total fork length. mm) for Arctic Grayling tagged during the
Piscivore Behavior Monitoring Study of 2023. .....................................................26
LIST OF TABLES
Table 4-1. Array deployment locations for Zone 1, Zone 2, and Zone 3. .....................................13
Table 5-1. 2023 Encounter history for species, lifestages, fish community zones, and
observation periods by encounter method (sampling method) from May-
September of 2023. This table will be updated to populate the full species-
specific periodicity table shown in Figure 4-1. ......................................................17
APPENDICES
Appendix A-1 – Preliminary Nuyakuk River Radio Telemetry Array Deployment and
Performance Information
Appendix A-2 – Preliminary Acoustic Smolt Data Analysis
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
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Nushagak Cooperative, Inc. v December 2023
ACRONYMS AND ABBREVIATIONS
2D two-dimensional
ADFG Alaska Department of Fish and Game
ARWG Aquatic Resources Working Group
dB decibel
BBSRI Bristol Bay Science and Research Institute
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
m meter
MHz megahertz
mm millimeter
Project Nuyakuk River Hydroelectric Project (P-14873)
PSP Proposed Study Plan
RSP Revised Study Plan
s second
microsecond
USR Updated Study Report
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 1 December 2023
1.0 INTRODUCTION
The focus of the Fish Community and Behavior Study Plan is understanding the seasonal
presence and distribution of anadromous and resident salmonids as well as seasonal habitat use
by fishes in the Nuyakuk Falls Reach. This information will be essential for evaluating the
potential impacts (positive and negative) associated with Project development and operation.
Further, results of this study in Year 1 (2023) are important inputs to models including the Life
Cycle Model, Agent Based Model, and Integrated Risk Assessment.
The Federal Energy Regulatory Commission (FERC) approved Revised Study Plan for Year 1
included the following components: 1) implementation of several candidate sampling methods
suitable for the three zones of the Project study reach to sample fish, 2) a radio telemetry study to
assess adult salmon upstream migration behavior and predator movement patterns, and 3) a
hydroacoustic study to assess the timing and in-river distribution of downstream migrating
salmon smolts.
The methodology for Year 1 included a suite of fish collection methods in the three Project Area
zones including:
minnow trapping,
seine netting,
gill/trammel netting, and
visual observations.
The intent behind the synergy of these methods is to refine the draft species/lifestage periodicity
chart that was developed during study planning based on available literature and Aquatic
Resources Working Group (ARWG) input.
The radio telemetry study included deployment of passage arrays at the downstream and
upstream extents of the Study Area and a behavior/passage route array in the Falls Reach. In
addition, upcoming mobile telemetry tracking in the winter of 2023/2024 will focus on resident
fish use of habitats immediately downstream.
An 8-head hydroacoustic array (upward and side-looking split-beam echosounder) was deployed
above the Falls Reach to characterize the horizontal and vertical distribution of downstream
migrating salmon (smolts, fry) as they approach the Falls and proposed Project. Data collected
from the sonar array in 2023 and 2024 will also be used to support the Entrainment Study, which
will be implemented in 2024.
2.0 STUDY GOALS AND OBJECTIVES
The primary goal of this two-year study is as follows:
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Determine the seasonal timing, species composition, relative abundance, habitat use, and
migratory patterns (distribution) of fishes within the Project Area.
Specific questions that will be addressed by this study:
1. What fish species use the aquatic habitats in the Project Area across seasons?
a. Focus on piscivores at intake, potential groin area, in the Falls, powerhouse
tailrace, and Falls tail out.
b. Seasonal movements and habitat use by Arctic Grayling.
2. What is the relative abundance of fishes in the Project Area seasonally?
3. What are the baseline migratory patterns and behaviors (such as timing, holding, number
of attempts) evident for Sockeye and Chinook salmon passing upstream through the
Project Area?
4. What is the proportion of adult salmon that successfully pass through the Falls Reach
under baseline conditions?
5. What is the baseline condition of injury/mortality in adult salmon observed downstream
of the Falls proper?
6. What is the baseline migration pattern and distribution across the channel for Sockeye
and Chinook salmon passing downstream through the Project Area?
7. What is the proportion of juvenile salmon that successfully pass through the Falls Reach
under baseline conditions?
8. What is the baseline condition of injury/mortality in juvenile salmon passing the Falls
proper?
9. Is there visual evidence of avian or mammalian predation of salmon smolts in the Project
Area across seasons?
3.0 STUDY AREA
The Fish Community Study Area includes three zones that comprise the ~500 m reach below the
Falls (Zone 1), the Falls Reach itself (Zone 2), and the 500 meters (m) above the Falls (Figure
3-1). In most cases, methodologies applied to survey and assess the fish community and species
distribution were conducted by zone and by transect within each zone.
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Figure 3-1. Fish Community Study Area showing Zone 1 (Downstream of Falls), Zone 2 (Falls
Reach), and Zone 3 (Upstream of Falls).
The width of the Nuyakuk River within the Project Area is approximately 150-210 meters wide
at the Project Area. Directed fish collection techniques focused on the margins of the stream
banks due to the potentially hazardous conditions across the rest of the channel.
4.0 METHODOLOGY
There are numerous methods that can be used for sampling fish in riverine systems, but the
effectiveness of each is highly dependent on prevailing sampling conditions (water velocity,
depth, turbidity, water temperature, etc.), target fish species, fish lifestages, fish behavioral
characteristics, and the timing of sampling. Based on available information, the Cooperative and
ARWG collaboration on the Preliminary Study Plan (PSP) included several candidate sampling
methods deemed initially suitable for the three zones of the Project study reach. In 2022, a field
methods feasibility study was completed that evaluated potential utility of various methods at the
Project site. The results of this effort were used to select the methods more likely suited for
successful data collection at the Project site and incorporate into the Revised Study Plan (RSP).
The RSP methods for the Fish Community Study included an initial compilation and review of
literature. This review and each of the methods implemented in Year 1(2023) are described
below.
4.1 Literature Review
Understanding the species and lifestage periodicities of fish in the Nuyakuk River was important
for determining appropriate sampling times for certain fish species likely to be present,
especially during migrations. The initial periodicities were based in part on a general
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understanding of the local populations as described in the published literature and refined during
Year 1 study implementation.
Based on this review and discussions with stakeholders, a preliminary species/lifestage
periodicity chart was developed for use in the Aquatics and Fish Resources studies (Figure 4-1).
This figure will be revised and updated following completion of the Year 1 and Year 2 studies as
more site-specific data on fish periodicity is obtained and corroborated between study years.
Figure 4-1. Preliminary lifestage periodicity for a sample of the fish species utilizing the Nuyakuk
River, Alaska. Subject to revision.
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4.2 Fish Sampling Methods
The RSP identified five fish sampling methods that may be applicable in the Project Area to
characterize: 1) Fish Community, 2) Upstream Adult Salmon Migration, 3) Downstream
Juvenile Salmon Migration, and 4) Timing, Distribution, and Relative Abundance of Piscivores.
During Year 1, the Nuyakuk River experienced late break-up and rapid snowmelt from an
unusually high snowpack and late thaw. There was a limited period when flows were conducive
to working in the river and the fish team prioritized installation of acoustic telemetry equipment.
Unfortunately, flows rose very rapidly in the spring and transect sampling was not possible.
Flows remained at peak levels through July. During late July, flows had receded and transect
sampling was conducted at six transects upstream and four transects downstream of the Falls.
Methods that were used during Year 1 studies including, seining, minnow trapping, gill/trammel
netting, visual observations, and angling, as described below. While electrofishing and trammel
nets were not implemented in Year 1, all candidate methodologies will be reconsidered for
implementation in Year 2 based on knowledge gained during Year 1 studies and prevailing
environmental conditions.
4.2.1 Seining
Hand-held or boat-assisted shoreline seines (10 m long, 1.5 m deep, comprised of 3-6
millimeters [mm] mesh) were used to target juvenile salmon and small-bodied resident fish
species. Hand seines were deployed in shallow areas along the shoreline with one end anchored
to the shore and the other end extended toward the thalweg and then looped to encircle the fish as
the ends were pulled in. Larger seines (50 m long, 3 m deep, comprised of 13-25 mm square
mesh) were used to target adult resident fish species. Multiple seine pulls (2-4) were required to
successfully sample study reaches.
4.2.2 Minnow Trapping
Minnow traps are an effective method for passive capture of juvenile salmonids and other
juvenile resident fish species in slow moving water (Bryant 2000). Wire traps were baited with
commercially sterilized salmon roe and soaked overnight for 16-24 hrs. Approximately 5-10
minnow traps were deployed at each study transect/stream bank where appropriate depth and
flow conditions allowed. Minnow traps were placed on the stream bottom, parallel to the current
in areas of cover. Each trap was anchored by a line and identified with flagging, the name and
contact information of the Cooperative’s study lead, and the applicable Alaska Department of
Fish and Game (ADFG) fish collection permit number. Though it was anticipated that minnow
trap deployments would be stratified across sample quadrants, slow water habitats with suitable
depth were not always available.
4.2.3 Gill/Trammel Netting
Gill nets can be an effective technique to survey the presence and relative abundance of fish
populations for a wide range of anadromous and resident species (Crawford 2007). Gill nets
provide an alternative technique for sampling deeper, non-wadable, mid-channel waters. One
limiting factor of gill nets is that they are designed to intentionally entangle fish so mortality can
be high. Trammel nets differ from gill nets in that instead of a single wall of netting, trammel
nets consist of three layers of netting tied together on a common float line and lead line During
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the 2023 sampling season, no mortalities were incurred so gill netting was implemented
throughout the fish community sampling effort rather than trammel netting.
At sites with current, gill nets were deployed as drift nets and allowed to drift through the sample
area. In slow water habitats, gill nets were deployed as set (fixed) nets for a pre-determined
amount of time while field crews maintained constant watch and collected the nets at the first
indication of a fish capture. Ideally, nets would cover the entire depth of the stream channel
where set, but some areas of the Nuyakuk thalweg were more than 20 feet deep which was
greater than the depth of the gill nets. A range of gill net sizes was used from 50 to 125 feet in
length and 6 to 8 feet in depth. Variable monofilament mesh sizes ranging from 0.5 to 5.0 inches
were used to target a range of fish species and sizes. Multiple passes (typically 2 to 4) were
necessary to adequately sample the channel width.
4.2.4 Visual Observations
Fish abundance and distribution surveys in Year 1 also employed visual identification and
videography of migratory fish behavior occurring in the study area. This included milling
behavior, passage attempts, and leaping at various sections of the Falls reach. Underwater video
and snorkeling were used to observe fish presence and behavior in places where net sampling
was not effective or possible. An AquaView color fish-eye underwater camera was mounted to a
10-foot pole and deployed from the bow of the research boat. Field staff observed the output
screen as the boat was drifted down the designated sampling transects and all fish species
observed were recorded. The underwater camera was also used to observe the milling/schooling
group of adult salmonids at the base of the Falls. The magnitude of the Sockeye school at the
base of the Falls made net sampling for other adult fish in that area impossible. A series of 10-
minute video exposures were used in different areas to determine whether there were adult
Chinook, Dolly Varden, Arctic Grayling, or other fish species present within the massive school
of Sockeye.
Downstream of Nuyakuk Falls, snorkeling was also used to supplement net sampling and
videography to identify whether any additional species were present and how many observed
fish were using the deep pools and other complex habitat along four transects running parallel to
the three primary chutes of the lower Falls Reach. Two snorkelers completed each transect while
a third field staff member recorded data and stood by to deploy a throw rope if necessary. Drone
footage of Sockeye staging below the lower Falls was also captured to document milling,
staging, and passage route queuing behavior.
Drone footage will be further reviewed over the coming months to characterize Sockeye Salmon
migratory behavior. Attempts to document fish holding or resting in pools as well as passage
routes within Zone 2 will also be conducted. Drone surveys along with visual observations may
also provide information on whether any spawning occurs within the proposed reach, specifically
near proposed Project elements (e.g., tailrace, intake, or groin locations), and will allow for
documentation of the nearest redd locations to the Project.
Visual observations were also made on the presence of potential spawning gravel and active
spawning activity within the study area, the presence of predators (i.e., arctic terns, otters, bears,
mergansers, loons), the presence of carcasses, and also the behavior of adult Sockeye and other
fishes. Instances of adult salmon holding, milling, searching, or jumping at passage obstacles
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were noted and will be incorporated into modeling efforts under the Fish Passage Study
(Attachment B). Any gravel patches observed during visual surveys were documented, sampled
to determine size classes, and measured for total area. Where spawning was observed, output
from two-dimensional (2D) models will be reviewed to define areas where potential changes in
operational flows could dewater or scour observed redds.
Environmental conditions (weather, water clarity/turbidity, discharge/depth, sun angle, glare,
etc.), flight path, areas of fish concentrations, and fish behavior were recorded during each
sampling survey.
4.2.5 Angling
Angling was included in the ADFG permit to sample piscivores for radio telemetry tagging and
was discussed during the ARWG workshop on Year 1 study methods. Since net deployment in
the lower Falls Reach was not possible during the late June through early August Sockeye run,
angling was an effective method not only for collecting Arctic Grayling for the radio telemetry
study, but also to sample other adult resident fish and piscivores in the Study Area. Angling
included use of both spinning rod/reel with single barbless spinning lures, and with fly fishing
gear and dry flies, streamers, and floating mouse/grasshopper patterns.
4.3 Fish Community
The application of sampling methods differed between zones due to varying sampling conditions
that included areas in Zone 2 which would have been hazardous to sample due to swift water
conditions and lack of safe egress. As a result, the surveys conducted in Zone 2 were limited due
to both the effectiveness of the methodology and constraints in sampling imposed by these
unsafe conditions. Strict safety protocols were developed and employed during all fish sampling
activities.
In Zones 1 and 3, sampling targeted juvenile Pacific salmon and resident fish species. Transects
were established at 200-meter intervals in Zones 1 and 3 and each transect was surveyed during
summer and fall sampling events. The presence of edge ice, deep snow, and site access issues in
April and early May prohibited the originally planned early spring sampling period. Therefore,
the first seasonal sampling event for fish community metrics occurred in late June.
Based on the average annual hydrograph, sampling events were proposed during low flows in
April to May (during lower spring discharge conditions), June to July (during high flow
conditions), and again in August to September (under decreased flow conditions); however, the
access issues noted above resulted in sampling events that included a high-flow period (June to
July), low flow period (August), and two sampling sessions focused on edge habitat surveys for
emergent juveniles and smolts, and predators in mid-May and late September. This fish
collection period during the ice-free conditions allowed for surveys to cover most of the time that
fish would likely be migrating through or residing in the Project Area.
In addition, winter sampling will focus on resident fish use of habitats immediately downstream
and upstream of the Falls and will be conducted during the upcoming winter of 2023/2024. This
sampling will include the use of underwater imagery in holding habitats, as well as monitoring
tagged Arctic Grayling within the Project Area. Two winter sampling events are planned, one for
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late November or early December 2023 when fish have likely moved to overwintering areas and
one for late winter just prior to the anticipated downstream migration of Sockeye Salmon
juveniles in late April or mid-May of 2024.
In some cases during 2023 sampling, attempts to operate trammel nets, gill nets, and seines in
mid-channel habitats was not successful due to depth and velocity conditions. Fish collection
surveys occurred over a 50-m-long reach located on both stream banks beginning at the
downstream end of each transect or where bank structure and current velocities allowed
deployment of sampling gear. At least three sampling methods within each transect area were
utilized to maximize the potential for capturing different species and lifestages that may occupy
different habitats.
As noted above, fish sampling in Zone 2 occurred on an opportunistic basis at locations that were
determined safe to sample based on depth and velocity, and typically included the deployment of
minnow traps and visual observations via underwater videography. Instream margins and
accessible slow-water habitats were the focus in Zone 2 to identify juvenile rearing opportunities
within the Falls section.
4.4 Downstream Salmonid Smolt Migration
4.4.1 Equipment Deployment
In coordination with the upcoming Year 2 Entrainment Study, hydroacoustics (upward and side-
looking split-beam imaging sonar) were used to characterize the horizontal and temporal
distribution of downstream migrating salmon (smolts) as they approach the Falls and proposed
Project. Hydroacoustic sampling was combined with fish collection methods targeting migrating
smolts to validate species detections in Year 1.
The 2023 hydroacoustic array consisted of eight up-looking sonar pods (6-degree beam angle)
deployed at 15 m intervals across the thalweg of the Nuyakuk River. The sonar pods were
deployed immediately upstream of the Falls near the proposed intake structure. In addition, a 2-
degree side-looking sonar was deployed on the right bank to cover approximately 60-90 m of the
near-surface water column. Figure 4-2 presents a schematic of the deployed hydroacoustic array.
The location for the sonar installation was selected based on extensive substrate monitoring via
underwater video of 13 potential transects identified during feasibility testing in 2022. A
comprehensive methodology of the sonar deployment, operational configuration, and calibration
will be presented in an upcoming Technical Memorandum as Appendix A-2 of this report
(Mueller et al. 2023, in progress).
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Figure 4-2. Hydroacoustic array configuration showing up-looking 6-degree beam sonar
transducers (T1-T8) and the side-looking 2-degree beam.
The up-looking hydroacoustic sonar heads were bolted to weighted aluminum sled-shaped
mounts and connected in a daisy-chain with waterproof abrasion-resistant data cables mated to
3/8" aircraft-grade stainless steel cable (Figure 4-3). Aluminum sleds were designed to be stable
in swift currents and to avoid tumbling or tipping during installation. The cable-sonar assembly
was pulled across the river using a Warn power winch.
The data cables for the up-looking and side-looking array were connected to the control module,
a 500-amp hour 24-volt marine deep cycle AGM battery bank, with a control computer running
the system. Data were backed up daily to external 2 terabyte hard drives to avoid any data loss.
The control system and power source were housed in a large tent staked to the ground above the
ordinary high-water mark.
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Figure 4-3. Hydroacoustic components prior to installation on May 12, 2023. Bright green data-cable
was mated to stainless cables. Sonar heads were bolted into custom made aluminum sleds
weighted with recycled free weights.
4.4.2 Sonar Operations
After the initial setup, data collection parameters were further refined to the following starting on
May 27, 2023.
Side-looking sonar:
source level: 224 decibel (dB)
power setting: -10 dB
pulse duration: 200 s)
maximum range: 100 m
ping rate: actual 4 pings per second (s) (= less than speed of sound limit of 7 pings
per second; limiting factor: data write time for high volume split-beam information,
i.e., including phase information)
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beam mode: split-beam
Up-looking sonar:
source level: 200 dB
pulse duration: T2, T3, T4, T5, T6: 33 s; T1, T7, T8: 130 s
maximum range: 5 m or less (depending on water depth at transducer location)
ping rate: actual 19 pings per s
beam type: single-beam
The BioSonics DTX Sonar System has the option to run the side-looking sonar in single-beam
mode. On June 12, 2023, the side-looking beam mode was changed to single-beam, allowing for
a significantly faster ping rate of 6.7 pings per s, which is close to the ping rate limit imposed by
the speed of sound (NOTE: sufficient time must be allowed for sound to travel to the maximum
range and back before next ping can be transmitted). The higher ping rate is beneficial because it
improves data characterization, in particular the distinction between smolt schools and clouds of
entrained air that need to be excluded from the analysis.
4.4.3 Data Analysis
The up-looking sonar transducers were used to inform analysis of temporal distribution while the
side scan transducer data was used to analyze distribution across the river. Real world cross-
referencing of transducer locations and side-looking aim was based on an overhead drone image
taken on June 20, 2023, which was georeferenced in ESRI ArcGIS Pro against the georeferenced
high-resolution imagery provided by McMillen. Reference points included identifiable features
along the shoreline (distinct trees and other shoreline features) and large distinct rocks in the
river that were visible on both images.
All acoustic data processing was done with Echoview Version 13.1., in part automated with
COM automation developed in Visual Studio 2022. For additional details on the Echoview
analysis, see below. Finally, Microsoft Excel was used for higher level summarization, data
examination for quality assurance and control, and final preparation of charts and tables.
4.4.3.1 Echoview Data Screening
For high-level identification of possible smolt passage events, we processed data collected with
up-looking transducer T4. We chose T4 because, from our preliminary review, we had
determined that it had the best echogram covering one of the highest smolt passage rates. Data
from T4 was auto-processed for organizing data files into day folders, creating one Echoview EV
file per day and loading all corresponding T4 data files into the EV file. This step was followed
by a fast manual review and manual adjustments of the surface exclusion line that was needed to
remove surface echoes from the analysis. After this manual interactive step, the data was sent
back through the automation for echo integration over 1 hour by 0.2 m depth increments.
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4.4.3.2 Echoview Process for Smolt Density Estimates
All acoustic data were processed with a volume back scattering strength (Sv) threshold that
produced the best contrast between smolts and background: side-looking data at -44 dB; up-
looking data at -36 dB. Side-looking data showed a background of bottom and surface
interference. Beyond 70 m, the interference was dynamic and so severe that we could not
separate it from smolt signals; therefore, we limited the analysis to a maximum range of 70 m.
For up-looking data the process was simpler because here, the data did not contain static
background noise that we could have removed. As a result, there were only two simple steps that
had to be done interactively: adjusting the surface exclusion line (which had to be shifted up as
the water level increased over the study period) and masking periods of noise (wind, rain, boat
noise).
In this study, the physical size of the smolts was unknown; therefore, we scaled the analysis to an
arbitrarily chosen total physical length of 11 cm (here referred to as “standard smolt”), which
bs) of 3.6E-05), based on an empirical equation that relates physical
fish size to dorsal aspect acoustic size (Love, 1971). Given the cylindrical shape of the smolt
swim bladder (main reflector of sound at this frequency), one can expect the acoustic size of
smolts in dorsal aspect to be similar to that in ventral aspect.
4.4.3.3 Conversion from Smolt Density to Smolt Passage Rates
The smolt density derived from the echo integration is an estimate of the mean smolt density per
area (smolt per square meter) in the circular cross-section (i.e., perpendicular to the acoustic
axis) over the integration interval. For the up-looking sonar, the reference plane of the area
density is horizontal, i.e., in the plane where the smolt distribution is random (at least over the
scale sampled) and can thus be expected to result in a cumulatively uniform distribution over the
integration interval of 1 hour (at least on average). For the side-looking sonar, the circular beam
cross-section is vertical; thus, the plane containing smolt distribution is not uniform. This makes
the conversion from the (hourly) measured density to passage rate slightly more involved
because the density is measured within the circular beam cross-section, which is different from
the density in an area of equal height (height same as circle diameter).
4.5 Upstream Adult Salmon Migration/Radio Telemetry
Methods for characterizing upstream migratory behavior of adult Sockeye and Chinook salmon
included visual survey methods and active radio telemetry. Field testing in 2022 informed the
potential effectiveness of active telemetry, and radio telemetry was selected as the most effective
tool to monitor upstream behavior and timing of adult Sockeye and Chinook arrival. Results of
the field testing and recommendations to implement a radio telemetry study were presented to
the ARWG in September of 2022, and approved for implementation in Year 1.
Upstream adult salmon migrations for adult Sockeye were studied using a two-part approach to a
radio telemetry behavior assessment. A 12-antenna radio telemetry array was installed and
included four receivers that monitored the passage timing and migration success of tagged fish
from a release point downstream of Zone 1 through Zones 2 and 3. In addition. seven antennas
that were deployed to monitor passage route selection of tagged Sockeye through the Falls Reach
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in Zone 2 (Figure 4-4). The location of the deployed arrays is presented in Table 4-1, and further
described in Appendix A-1.
Figure 4-4. Radio telemetry array deployment locations. Each passage array includes one antenna
while the Zone 2 Route Selection Array includes eight antennas deployed on both banks of the
river. Inset shows detail of Route Selection Array (Zone 2) placement.
Table 4-1. Array deployment locations for Zone 1, Zone 2, and Zone 3.
Site ID Site Description Bank Receiver Type Location Antenna
Type
Antenna
Gain Northing Westing
001 Fallback/Zone 1 Right Lotek SRX 600 59.91418 -158.08621 4-element 50
002 Study State/Zone 1 Right Lotek SRX 800 59.90629 -158.11027 4-element 50
003 Upstream/Zone 3 Left Lotek SRX 600 59.90823 -158.12818 4-element 80
004 Exit/Zone 3 Left Lotek SRX 800 59.90486 -158.15834 4-element 90
010 Lower Falls/Zone 2 Left Sigma 8 Orion 59.90973 -158.11397 3-element -80
011 Lower Falls/Zone 2 Mid Lotek SRX 600 59.90912 -158.11593 3-element -45
012 Lower Falls/Zone 2 Right Sigma 8 Orion 59.90934 -158.11663 3-element -80
013 Mid Falls/Zone 2 Right Sigma 8 Orion 59.91124 -158.11935 3-element -100
014 Mid Falls/Zone 2 Left Sigma 8 Orion 59.91206 -158.11642 3-element -80
015 Upper Falls/Zone 2 Left Sigma 8 Orion 59.91210 -158.12020 3-element -100
016 Upper Falls/Zone 2 Right Sigma 8 Orion 59.91098 -158.12108 3-element -100
Adult Sockeye were collected at the release point using dip nets. Due to the extreme number of
fish present, more invasive netting techniques (i.e., seining, gill netting) were not required for
most of the collection effort. Sockeye were externally tagged with Lotek MCFT2-3EM Radio
telemetry transmitters with a burst rate of 10 seconds and frequency of 150.300-150.380
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megahertz (MHz). Three-hundred-pound (lb) monofilament and size F aluminum crimp sleeves
were used to affix the tags. These tags weigh 10.0 g in air and 4.6 g in water, and have a tag life
of approximately 532 days.
Sterilized PIT-tag needles were used to punch two holes through the dorsal muscle below the
dorsal fin to allow a passthrough of the monofilament tethers. Once both monofilament tails
were passed through the muscle, an aluminum crimp sleeve was crimped to secure the tag in
place with the antenna trailing (Figure 4-5). Tag number, sex, fork length, total height, and
caudal height were measured and recorded for each fish. Release times were recorded, and all
tagged Sockeye were observed to verify unaffected swimming behavior.
Figure 4-5. Tagging detail for adult Sockeye.
Details of radio telemetry equipment deployment, configuration, and methods for array testing,
calibration, and performance will be presented in the (Updated Study Report (USR) to be
completed in 2024.
4.6 Timing, Distribution and Relative Abundance of Piscivores
ADFG has expressed concern that the Falls habitat may be an important feeding area for resident
fishes. To help improve an understanding of resident fish use in the Project Area, radio telemetry
in combination with underwater camera observations were used to evaluate Arctic Grayling and
Rainbow Trout. Details of radio telemetry equipment deployment, configuration, and methods
for array testing, calibration, and performance will be presented in an upcoming Technical
Memorandum (Thompson et al. 2024, in progress) pending the completion of Year 1 telemetry
studies and winter predator monitoring.
Arctic Grayling and Rainbow Trout were captured primarily using hook and line techniques with
single dry flies, nymphs, and single-hook spinning lures. All captured fish were held in 20-gallon
containers with fresh river water. Fish surgeries were performed by a veteran fish surgeon with
over 2,000 surgical procedures completed on a wide variety of species. All surgeries, including
protocol for anesthesia of salmonid fishes using MS-222, were performed per the Standard
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Operating Procedure for the Surgical Implantation of Transmitters in Salmonids published by the
U.S. Geological Survey (USGS) (Liedtke et al. 2012). The types and sizes of tags were
determined based on 2022 field methods testing.
Fish were tagged with Lotek NTF-5-2 nano tags weighing 1.5 g in air and measuring 15x8.2
mm. We used 4-0 Vicryl monofilament sutures and applied two interrupted sutures to the
incision, and an 18 gauge catheter was used to place the transmitter antenna through the body
cavity wall (Figure 4-6). All fish were kept on a light dose of tube-fed MS-222 solution until the
first suture was in place and switched to cold freshwater for the remaining suture. The surgically
implanted nanotags ping at 10 second intervals on 150.300 and 150.388 MHz and have an
estimated tag life of 357 days from activation. All fish were completely recovered in clean river
water prior to release. Fish species, length, tag ID, and pinging frequency as well as release time
were recorded.
Figure 4-6. Detail showing closed incision with interrupted sutures and trailing radio transmitter
antenna on an Arctic Grayling captured at the outfall of the Falls Reach in July 2023.
Tagging occurred in the early spring, summer, and fall at locations immediately downstream of
the Falls, but also in limited and safely accessible areas within the Falls Reach. This analysis,
currently ongoing, will allow the evaluation of Arctic Grayling behavior during salmon
outmigration as well as the overwintering period. Assuming proximal collection locations to the
Falls, 30 tags were proposed to be allocated for each tagging group in the spring and fall for a
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Nushagak Cooperative, Inc. 16 December 2023
total of 60 tags deployed. Successful capture rates resulted in a total of 73 Arctic Grayling and
two (2) Rainbow Trout (442 mm and 752 mm) being tagged in 2023. Additional effort is planned
to augment the number of tagged Rainbow Trout during fall sampling in 2023 to assess
movement patterns and winter holding trends. The telemetry array established for adult salmon
behavior was refined to also support movement detections and/or residency of tagged Arctic
Grayling and Rainbow Trout within the three sampling zones.
Monitoring of tagged piscivore movements will continue through the fall and winter of 2023
using mobile radio telemetry receivers. Mobile tracking transects in the fall will run the entire
length of Zone 2 on both banks via foot surveys. Zone 1 and Zone 3 will be surveyed via boat.
During winter surveys when ice and snow are present, all surveys will be conducted from the
bank on foot. Global Positioning System (GPS) positions of all mobile detections will be
recorded to determine where tagged fish have moved from the time of tagging during the 2023
summer to winter 2023/2024. As noted above, the detailed methodologies for mobile tracking
efforts will be presented in the upcoming telemetry-focused Technical Memorandum (Thompson
et al. 2024, in progress) and in the USR to be completed in December of 2024.
5.0 RESULTS
5.1 Fish Community
Actions completed in pursuit of the fish community objectives included: collections of fish
abundance and distribution data; presence and timing of out-migrating smolts via net and trap
sampling; sonar and radio telemetry monitoring for adult Sockeye and piscivores. The activities
completed under this phase of the Nuyakuk Hydroelectric Project are outlined in Figure 5-1,
including hydrologic data from the USGS Nuyakuk Stream discharge gage located near the
outlet of Tikchik Lake (Station No. 15302000).
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 17 December 2023
Figure 5-1. Fish community data collection period over the Year 1, 2023 season.
The analysis of fish community distribution and relative abundance is forthcoming following
completion of the Year 1 studies in 2023 and will be included in the USR. Table 5-1 presents the
initial fish species list encountered during Year 1 studies, the project zone where fish species and
life history stages were encountered, and the periodicity of those observations. Data on fish
community including relative abundance, seasonality, and other metrics will be presented
following the completion of 2023 studies in October of 2023.
Table 5-1. 2023 Encounter history for species, lifestages, fish community zones, and observation
periods by encounter method (sampling method) from May-September of 2023.
This table will be updated to populate the full species-specific periodicity table
shown in Figure 4-1.
Common Name Species Name Lifestage
Project
Zone
Encounter
Method1
Observation
Period2
Chinook Salmon Oncorhynchus
tshawytscha
fry 1 SE, VO June 15-July 16
smolt 1, 2, 3 SE, VO June 15-Aug 15
adult 2 VO July 2
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 18 December 2023
Common Name Species Name Lifestage
Project
Zone
Encounter
Method1
Observation
Period2
Sockeye
Salmon Oncorhynchus nerka
fry 1, 2, 3 SE, VO, MT May 15-Sept 30
smolt 1, 2, 3 SE, VO, MT May 15-Sept 30
adult 1, 2, 3 GN, AN, VO June 15-Aug 30
Grayling Thymallus thymallus
adult 1, 2, 3 AN, VO June 15-Aug 30
juvenile 1, 3 VO Aug 28-Sept 1
smolt 1 SE Aug 26
Pink Salmon Oncorhynchus gorbuscha fry 1, 3 SE, VO June 15-July 15
Coho Salmon Oncorhynchus kisutch fry 1, 3 MT, SE June 24
smolt 1, 3 SE June 25-Aug 15
Arctic Lamprey Lampetra camtschatica smolt 1 MT June 24
Chum Salmon Oncorhynchus keta adult 1 VO July 4
Pike Esox lucius adult 3 VO June 15-Sept 30
juvenile 1 SE Aug 26
Humpback
Whitefish Coregonus pidschian juvenile 1 SE June 25
Pygmy
Whitefish Prosopium coulterii juvenile 1, 3 SE June 30-Sept 30
Burbot Lota lota 3 MT Aug 23
Sculpin3 Cottoidea juvenile 1, 3 SE June 25
adult 1, 3 MT June 30-Sept 30
Lake Trout Salvelinus namaycush adult 2 AN Aug 25
Rainbow Trout Oncorhynchus mykiss adult 1, 2, 3 AN May 15-Sept 30
3 Spined
Stickleback Gasterosteus aculeatus adult 1, 2, 3 SE May 15-Sept 30
9 Spined
Stickleback Pungitius pungitius adult 1, 2, 3 SE May 15-Sept 30
Notes:
1. Encounter Methods include: seine (SE), Visual/Video Observation (VO), Minnow Trap (MT), Angling (AN), Drift Gill Net (GN).
2. A range is provided when observations occurred over a period of time. Single observations (Chinook adult, lake trout) are
noted on a single date.
3. Sculpin were not identified to species during Year 1.
5.2 Downstream Smolt Migration/Hydro-acoustics
The hydroacoustic array, including eight up-looking sonar transducers and one side scan sonar
transducer, was successfully installed across the thalweg of the Nuyakuk River approximately
500 feet above the crest of the Falls (Figure 5-2). The sonar operated from May 16-July 13, 2023
which coincided with visual observations of smolts during other fish community sampling
efforts. Data analysis is ongoing. A Technical Memorandum has been attached to this report as
Appendix A-2 to provide detailed analytical methods and results for assessment of downstream
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FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 19 December 2023
migration behavior and spatial distribution of smolts during the outmigration period of 2023
(Mueller et al. 2023, in progress).
Figure 5-2. 2023 Downstream smolt outmigration monitoring hydroacoustic sonar installation
including up-looking (green dots) and side scan (green triangle) sonar and control tent.
5.2.1 Hydroacoustic Data Analysis
Up-looking transducers T2, T3, T4, T5 and, with the longer pulse duration, T7 and T8 produced
good echograms for smolt analysis. The T6 unit was somewhat compromised by its poor aim
(30° tilt downstream), which was difficult to rectify. Given the uncertainty of how useful T6 data
will be, analysis of these data has been limited to one day for the initial analysis (June 20, 2023;
see below). For this day, its estimate is consistent with the general cross-river distribution
pattern.
A highly automated echo integration procedure was used with interactive supervision limited to
manual adjustments to exclude surface echoes from the analysis. The results of this screening
provides a good synopsis of the data (example Figure 5-3) that indicated a period of high-
resolution data indicating a likelihood of 2023 smolt passage events from May 29-June 3, 2023.
Additional days of high-resolution data include June 20-23 and July 1, 2, and 4, 2023.
The second part of the analysis strategy was to approach it in a tiered fashion, starting with a
detailed assessment of a first subset (Tier 1) before deciding on how to proceed. For this first
subset screening, results for 6 days with the cleanest, most conclusive looking data were
selected: May 29-June 3 and June 20, 2023. For this interim report, Tier 1 analysis has been
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 20 December 2023
completed, with the exception of up-looking transducer T6 (tilted transducer), for which we have
analyzed only on June 20, 2023.
Side-looking data showed backgrounds of bottom and surface interference. Beyond 70 m, the
interference was dynamic (shifting in range from ping to ping) and so severe that we could not
separate it from smolt signals; therefore, analysis was limited to a maximum range of 70 m.
Analysis was also limited to a minimum range of 20 m because at ranges < 20 m, the side-
looking 2° beam is too narrow to cover the top meter of the water column. An example of how
side scan sonar data is interpreted to evaluate smolt movement patterns is presented in Figure
5-4.
The full results for the Juvenile Salmon Downstream Migration will be presented in an upcoming
Technical Memorandum (Mueller et al. 2023, in progress) that will be completed in the late fall
of 2023. Final results will also be included in the USR to be completed in late 2024. Appendix
A-2 of this report provides initial analytical results.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 23 December 2023
5.3 Upstream Adult Salmon Migration/Radio Telemetry Study
5.3.1 Radio Telemetry Study
A total of 120 adult Sockeye Salmon were tagged with radio transmitters between June 28 and
July 11, 2023 with fork lengths ranging from 468-698 mm (Figure 5-5). The sex of radio tagged
fish was nearly equal with 51% male and 49% female fish tagged.
Figure 5-5. Fork length distribution of adult Sockeye Salmon tagged during radio telemetry study to
address upstream migration timing, success, and behavior at the Nuyakuk River Falls.
Initial results of the assessment of the performance of the radio telemetry array suggest that both
the detection efficiency (> 95%) and range (> 500 feet) were sufficient to satisfy the analytical
assumption that a fish passing a detection array would be successfully detected. This is an
essential factor in assessing passage success. An example of the results of detection range and
efficiency testing is presented in Figure 5-6 showing the GPS-tagged detections of two test tags
(ID 14 and 411) as they were detected by Receiver 4 which is located at the upstream end of
Zone 3 and represents the “Exit Array,” signifying that a tagged-Sockeye has successfully passed
the Falls and exited the study area.
The analyses of 2023 radio telemetry data including evaluation of the timing and periodicity of
passage events and passage success are on-going; however, preliminary results indicate that
96% of Sockeye tagged in Zone 1 successfully passed through the Falls Reach in Zone 2 and
exited the study area past receivers located in Zone 3.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 25 December 2023
5.3.2 Visual Observation
Visual surveys completed in combination with the radio telemetry study were used to estimate the
timing and spatial distribution of adult Sockeye Salmon as they migrated and staged within the
study area. Observations of Sockeye attempting to pass upstream of the biggest flow/velocity
barrier also informed other Year 1 studies including the Agent-Based Model described in the
Fish Passage ISR (Attachment B). For example, Sockeye were observed attempting to swim up
very shallow rock slopes (Figure 5-7) which represented an unexpected passage attempt.
Additionally, observations included many failed attempts of Sockeye leaping or jumping past the
significant whitewater obstacles that formed during high flows at each of the three chutes at the
base of the Falls (Figure 5-7 right). Observations of failed passage attempts diminished at lower
flows when the whitewater obstacles were less extreme. Drone imagery of staging adult Sockeye
documented the spatial and temporal distribution of salmon (Figure 5-8).
Figure 5-7. Example visual observation of an adult Sockeye Salmon passage attempt at the far left
bank of the Falls Reach (left panel), and the location where the passage attempt took place (right
panel).
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 26 December 2023
Figure 5-8. Drone footage showing where adult Sockeye were staging immediately below the right-
bank Falls chute at the downstream Nuyakuk Falls boat landing. July 2023. Photo M. Nobles.
5.3.3 Movement Patterns of Piscivores
A total of 68 Arctic Grayling were captured and surgically tagged with radio transmitters
between early July and September of 2023. Arctic Grayling ranged in size from 250 mm to 458
mm in fork length (Figure 5-9). Many fish were successfully detected at radio telemetry
receivers throughout the period of tagging from July to September of 2023. Continued
monitoring of movement patterns and results of these monitoring efforts are forthcoming as the
study continues into the winter of 2023 and 2024. These data will be comprehensively analyzed
in the USR.
Figure 5-9. Size distribution (total fork length. mm) for Arctic Grayling tagged during the Piscivore
Behavior Monitoring Study of 2023.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 27 December 2023
6.0 DISCUSSION AND FINDINGS
A comprehensive discussion of all study results will be provided in the USR pending the
completion of Year 1 and Year 2 study data collection and analysis.
The Cooperative worked extensively with members of the ARWG to identify study questions
and potential methods appropriate to address those questions. The Cooperative will continue
working with the ARWG to refine study methods in Year 2 based on Year 1 results to ensure
effective documentation of existing conditions, provide information to support both study design
and impact analysis, and ensure safe study conditions for all field staff.
7.0 STUDY VARIANCES AND MODIFICATIONS
1. The RSP indicated that Upstream Adult Salmon Migration Behavior should include
tagging of 100 adult Sockeye and 100 adult Chinook salmon. During 2023 sampling,
only one adult Chinook was observed via underwater videography at the falls, and low
numbers were observed at the BBSRI counting tower downstream. No adult Chinook
were captured and therefore, no adult Chinook were tagged for the 2023 telemetry
assessment of upstream migration patterns. As a result, 20 additional adult Sockeye were
tagged to increase the sample size.
2. The Fish Community portion of the RSP indicated that sampling would occur over three
sampling periods including early spring (April-May), summer (June-July), and fall
(August-September). Due to access issues to this remote site, and the heavy snow and
river ice still in place through April, it was not possible to begin Fish Community
sampling this early in the year. In May, extended high flows impeded fish community
sampling. Due to snow and ice in the river channel, limited beach seining and edge
sampling work was completed during mid- May to provide early-season corroboration to
the initial phases of the Downstream Smolt Migration Behavior Study. While a full suite
of Fish Community sampling was not conducted in April-May, three comprehensive
sampling efforts were completed in mid-June, mid-July, and late August/September to
meet the goals of the Year 1 study plan. If conditions and site access allow, we hope to
complete spring sampling during the original April/May timeline in 2024.
8.0 STUDY STATUS AND SCHEDULE
8.1 Fish Community
The Year 1 study is ongoing, with field efforts continuing through September and October of
2023. Following completion of Year 1 and Year 2 field sampling in 2024, all data will be quality
controlled, analyzed, and summarized in the USR.
8.2 Downstream Smolt Migration Behavior
The Year 1 portion of this study is complete, and all data have been quality controlled.
Behavioral analysis using hydro-acoustic data will be completed in October of 2023. Study
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 28 December 2023
details and results from Year 2 monitoring will be provided in the USR in 2024. Upstream
Migration of Adult Salmon
This Year 1 portion of the study is complete and data analysis is currently underway including
quality control of detection data, removal of false positive or erroneous data, and analysis of the
resulting detection history for each fish. Study details and results from Year 2 monitoring will be
provided in the USR in 2024.
8.3 Piscivores
This study is ongoing with field efforts and remote monitoring continuing into the winter of
2023. This will allow the evaluation of tagged predator (Arctic Grayling and Rainbow Trout)
movements between the summer and fall and fall to winter holding periods. Monitoring of
tagged predator behavior will continue into 2024 with a complete analysis of predator movement
over the two-year study period presented in the USR.
9.0 STUDY-SPECIFIC CONSULTATION
9.1 Consultation Summary
October 12, 2022: Nuyakuk Fish Study Methods Updates presentation to the ARWG.
Audrey Thompson presented the results of methods feasibility testing completed in
August of 2022 and provided suggestions for minor RSP revisions including: 1)
justifying the selection of radio telemetry techniques for upstream adult salmon migration
study; 2) site selection for the hydroacoustic study; and 3) siting recommendation for
videography transects during Year 1 (2023) sampling. The PowerPoint presentation is
available by request.
July 7, 2023: Email correspondence between study lead Audrey Thompson and Bryan Nass of
Bristol Bay Science and Research Institute (BBSRI).
BBSRI completed concurrent sampling at a location in the lower Nuyakuk River near the
confluence with the Nushagak River. Audrey Thompson provided details of the
methodology for external tagging of Sockeye and Chinook salmon, and coordinated on
delivery of radio tags provided by the vendor for use on the Nuyakuk in 2023.
August 9, 2023: Nuyakuk Fish Community and Radio Telemetry Study Update presentation to
the ARWG.
Audrey Thompson presented study updates, including the position of installed radio
telemetry receivers, a simple description of the tagging methodology for adult Sockeye,
select photographs of tagged fish, and preliminary information about the total number of
tagged fish that had (at that time) successfully ascended the Falls. The PowerPoint
presentation is available by request.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Attachment A
Nushagak Cooperative, Inc. 29 December 2023
9.2 Report Delivery Schedule
Year 1 Initial Study Report: To be provided to FERC and the Nuyakuk Hydroelectric Project
ARWG on December 1, 2023.
10.0 REFERENCES
Bryant, Mason D. "Estimating fish populations by removal methods with minnow traps in
Southeast Alaska streams." North American Journal of Fisheries Management 20, no. 4
(2000): 923-930.
Crawford, B. 2007. Variable Mesh Gillnets (in Lakes). In Salmonid Field Protocols Handbook:
Techniques for Assessing Status and Trends in Salmon and Trout Populations. State of
the Salmon. Portland, Oregon. pp 425-433.
Liedtke, T.L., J.W. Beeman, and L.P. Gee. 2012. A standard operating procedure for the surgical
implantation of transmitters in juvenile salmonids: U.S. Geological Survey Open-File
Report 2012-1267, 50 p.
Love, R. H. 1971. Dorsal-aspect target strength of an individual fish. The Journal of the
Acoustical Society of America 49(3): 816-823.
Mueller, A.M., A. Thompson, and M.L. Keefe. 2023. Technical Memorandum: Nuyakuk River
Smolt Downstream Behavior Analysis using Hydroacoustic Telemetry. Prepared for
Nushagak Cooperative. In progress.
Thompson, A.M., M.R. Nobles, K. Nebiolo, and M.L. Keefe. 2023. Technical Memorandum:
Nuyakuk River Adult Salmon Upstream Behavior Through the Falls Reach using Radio
Telemetry. Prepared for Nushagak Cooperative. In Progress.
Thompson, A.M., M.R. Nobles, K. Nebiolo, and M.L. Keefe. 2024. Technical Memorandum:
Nuyakuk River Seasonal Piscivore Movement Patterns in the Falls Reach using Radio
Telemetry. Prepared for Nushagak Cooperative. In Progress.
APPENDIX A-1:
Preliminary Nuyakuk River Radio Telemetry Array
Deployment and Performance Information
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 2 December 2023
This document describes the details of the deployment of radio telemetry equipment at the
Nuyakuk Hydroelectric Project Site, 2023.
Supported Studies:
Adult Sockeye Upstream Migration
Piscivorous Fish Movements
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 1 December 2023
1.0 Radio Telemetry Receiver Deployment 2023
Individual receiver deployment information and performance assessment completed to date are
provided on the following pages. An overview of the deployed locations map is provided in
Figure A-1.
Table A-1 provides antenna deployment locations including the deployment zone, receiver data
objective (passage or Falls behavior assessment), antenna type, gain settings, and power source.
Nuyakuk River Hydroelectric Project Fish Community and Behavior StudyFERC No. 14873 Initial Study Report – Appendix A-1 Nushagak Cooperative, Inc. 2 December 2023Table A-1. Antenna Deployment Locations including the deployment zone, whether the receiver data is being used for passage or Falls behavior analyses, the antenna type and gain settings, and the power source.
Nuyakuk River Hydroelectric Project Fish Community and Behavior StudyFERC No. 14873 Initial Study Report – Appendix A-1 Nushagak Cooperative, Inc. 3 December 2023Figure A-1. Overview of receiver deployments for the radio telemetry portion of the Nuyakuk River Fish Community and Fish Passage Studies, 2023.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 4 December 2023
2.0 Passage Timing and Success Array
Four receivers (01, 02, 03, 04) were used to monitor the success and timing of tagged adult
Sockeye ascending the Falls Reach in June and July of 2023. A description of each receiver’s
role in this assessment as well as deployment and performance data follow.
2.1 Receiver 01: Fall Back Array
This receiver was designed to determine if any tagged fish fell back downstream following
tagging, which occurred between Receiver 01 and Receiver 02. Receiver 01 position and results
from the range and detection efficiency testing are provided in Figure A-2.
Figure A-2. Receiver 01: Fallback Array position and range testing for tag ID 14.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 5 December 2023
2.2 Receiver 02: Study Area Arrival Array
This receiver was deployed about 500 meters above the tagging location to provide the “starting
line” for tagged adult Sockeye entering the study area. Calculations for travel time through the
Falls include first and last detection time stamps at this receiver. Any tagged adult Sockeye that
failed to arrive at Receiver 02 were omitted from the passage success study. The position of
Receiver 02 and results from the detection range and efficiency testing are provided in Figure
A-3.
Figure A-3. Receiver 02: Study Area Arrival Array position and range testing for tag ID 14 (Sockeye
tag) and tag ID 411 (Piscivore tag).
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 6 December 2023
2.3 Receiver 03: Upstream Arrival Array
This receiver was deployed about 250 meters upstream of the crest of the Falls, far enough
upstream that fish could not be detected until they had fully exited the turbulent whitewater
portion of the upper Falls and entered a slack, flow refuge. Detection at this location indicates
that a fish has successfully ascended the Falls. Any tagged fish that failed to be detected at
Receiver 03 or Receiver 04 further upstream were considered to have failed to pass the Falls.
The position of Receiver 03 and results from the detection range and efficiency testing is
provided in Figure A-4.
Figure A-4. Receiver 03: Study Area Arrival Array position and range testing for tag ID 14 (Sockeye
tag).
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 7 December 2023
2.4 Receiver 04: Study Area Exit Array
This receiver was deployed about one kilometer upstream of the crest of the Falls to detect adult
Sockeye that were transiting upstream from the vicinity of the Falls Reach toward either Tikchik
Lake or other points upstream. Detection at this location indicates that a fish has successfully
ascended the Falls and continued their upstream spawning migration.. Any tagged fish that failed
to be detected at Receiver 03 or Receiver 04 further upstream were considered to have failed to
pass the Falls. The position of Receiver 04 and results from the detection range and efficiency
testing are provided in Figure A-5.
Figure A-5. Receiver 04: Study Area Arrival Array position and range testing for tag ID 14 (Sockeye
tag).
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 8 December 2023
3.0 Passage Route Selection and Passage Behavior Arrays
Beyond the four receivers deployed to monitor overall passage timing and success, an additional
seven receivers (10, 11, 12, 13, 14, 15, 16) were deployed to monitor passage route selection,
holding patterns, and other behavior metrics within the Falls Reach (Zone 2). It was not possible
to perform the same range and detection efficiency testing that was performed for Receivers 01,
02, 03, and 04 as boat operation within the Falls Reach was not safe. Therefore, the following
sections describe the location of the Falls Behavior Array by receiver.
3.1 Receiver 10: Left Bank Falls Entry
This receiver was placed facing upstream and with a limited gain to focus detection range on the
pool immediately upstream of the far-left bank whitewater flume to identify fish that
successfully leaped or otherwise ascended via this access route to the Falls (Figure A-6).
Figure A-6. Deployment location for Receiver 10 monitoring adult Sockeye passing to the far left
bank of the lower portion of the Falls Reach.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 9 December 2023
3.1.1 Receiver 11: Mid Falls Staging Area Receiver
This receiver was placed facing downstream and with a broader gain to increase detection range
on the two large, deep pools immediately downstream of the flow paths with most of the flow
and apparently lower gradient than the far left or far right passage routes. This receiver was used
to monitor the amount of time that fish spent milling or staging below the Falls and, if possible,
analysis of whether fish exhibited the following behaviors: 1) multiple passage attempts
upstream or downstream; 2) coming and going from the Falls staging area prior to either
successfully ascending; or 3) falling back to downstream receivers (Figure A-7).
Figure A-7. Receiver location and directionality for Receiver 11 covering the deep pools below the
Falls, monitoring staging and residence time in the lower falls for tagged adult Sockeye.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 10 December 2023
3.1.2 Receiver 12: Right Bank Lower Falls
This receiver was placed facing upstream with a narrow gain allowance to detect fish that passed
upstream through the lowest of the Falls chutes on the far river-right side of the Nuyakuk River.
The antenna was directed downward, and below the bulk of the hill on the island to prevent the
receiver from detecting fish that were still staging in the pool downstream of the far-right chute.
Tagged adult Sockeye detected on this receiver will have passed either through the far-right, or
middle-right chutes of the lower Falls (Figure A-8).
Figure A-8. Deployment location of Receiver 12 focused on detecting adult Sockeye passing
through the river-right side of the lower whitewater section (chutes) of the Falls Reach.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 11 December 2023
3.1.3 Receiver 13: Right Bank Mid Falls
This receiver was positioned to detect adult Sockeye transiting a narrow band of slack/ low flow
habitat at the apex of the inside Falls Reach bend. The antenna was pointed slightly upstream and
the gain was restricted in this area where the Falls Reach is at its narrowest to restrict detections
to the right bank. Tagged adult Sockeye detected on this receiver will be classified as having
passed along the right bank of the middle Falls Reach (Figure A-9).
Figure A-9. Receiver 13 location positioned at the apex of the Falls Reach inside bend, right bank.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 12 December 2023
3.1.4 Receiver 14: Left Bank Mid Falls
This receiver was positioned to detect adult Sockeye transiting a narrow band of slack/ low flow
habitat at the apex of the outside of the Falls Reach bend. The antenna was pointed slightly
upstream, and the gain was restricted in this area where the Falls Reach is at its narrowest to
restrict detections to the left bank. Tagged adult Sockeye detected on this receiver will be
classified as having passed along the left-bank of the middle Falls Reach (Figure A-10).
Figure A-10. Receiver 14 location on the outer left bank of the middle Falls Reach.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
Nushagak Cooperative, Inc. 13 December 2023
3.1.5 Receiver 15: Left Bank Upper Falls
This receiver was positioned to detect adult Sockeye transiting a narrow band of slack/ low flow
habitat in the upper 100 m of the Falls Reach on the left bank. The antenna was pointed
downstream and gain decreased to restrict the detection range to the left side of the river. Tagged
adult Sockeye detected at Receiver 15 will be considered to have selected a left-bank passage
route at the top portion and upstream exit of the Falls Reach (Figure A-11).
Figure A-11. Receiver 15 location at the Upper Left Bank of the Falls Reach.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-1
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3.1.6 Receiver 16: Right Bank Upper Falls Reach
This receiver was positioned to detect adult Sockeye transiting above the Falls crest on the right
bank as they emerge from the whitewater and enter the slack water immediately upstream. The
antenna was pointed downstream and gain decreased to restrict the detection range to the right
side of the river. Tagged adult Sockeye detected at Receiver 16 will be considered to have
selected a right-bank passage route at the top portion and upstream exit of the Falls Reach
(Figure A-12).
Figure A-12. Receiver 16 antenna location at the Upper Right Bank of the Falls Reach.
APPENDIX A-2:
Preliminary Nuyakuk River Sonar Analysis of Smolt Outmigration
This document describes the details of the sonar system deployment and analysis of data
collected at the Nuyakuk Hydroelectric Project Site in 2023.
Supported Studies:
Fish Community
Entrainment and Impingement
Prepared by:
Anna-Maria Mueller
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 1 December 2023
Methods
Acoustic System Description
Equipment description …pull from BioSonics description, include:
Side-looking: 1 transducer
Frequency: 200 kHz
Nominal beam width: 2.1°
Sonar type: split-beam, optional single-beam mode
Up-looking: 8 transducers
Frequency: 120 kHz
Nominal beam width: 7°
Sonar type: single-beam
System integration, automation etc: BioSonics description
Acoustic System Installation
Deployment of side-looking transducer:
Nearshore, aimed across river, center of transducer at 0.2 m (+/- 0.1 m) depth; pitch angle
-0.6° (+/- 0.1°) [precise aim important because of long range, especially pitch angle]
Deployment of up-looking transducers:
On river bottom, aimed up towards the water surface [precise aim somewhat less important
because of ultra short range]
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Data Collection
After the initial setup, data collection parameters were further refined. After these initial
adjustments, the following data collection parameters were used starting 2023-05-27:
Side-looking sonar:
source level: 224 dB
power setting: -10 dB
pulse duration: 200 us
maximum range: 100 m
ping rate: actual 4 pings per s (= less than speed of sound limit of 7 pings per s; limiting
factor: data write time for high volume split-beam information, i.e., including phase
information)
beam mode: split-beam
Up-looking sonar:
source level: 200 dB
pulse duration: T2, 3, 4, 5, 6: 33 us; T1, 7, 8: 130 us;
maximum range: 5 m or less (depending on water depth at transducer location)
ping rate: actual 19 pings per s
beam type: single-beam
After learning that the BioSonics DTX system had the option to run the side-looking sonar
in single-beam mode, we made one additional modification: On 2023-06-12 we changed the side-
looking beam mode to single-beam, which allowed us to achieve a significantly faster ping rate of
6.7 pings per s, which is close to the ping rate limit imposed by the speed of sound (need to allow
sufficient time for sound to travel to the maximum range and back before next ping can be
transmitted). The higher ping rate is beneficial because it improves data characterization, in
particular the distinction between smolt schools and clouds of entrained air that need to be
excluded from the analysis.
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Data Analysis
Real world cross-referencing of transducer locations and side-looking aim was based on
an overhead drone image taken on 2023-06-20, which was georeferenced in ESRI ArcGIS Pro
against the georeferenced high-resolution imagery provided by McMillen. Reference points
included identifiable features along the shoreline (distinctive trees and other shoreline features)
and large well-defined rocks in the river that were visible on both images. Spatial placement and
verification of transducers was done in ESRI ArcMap 10.2., with the help of construction lines that,
through their distinct geometry, provided confident cross-reference between the georeferenced
drone image and additional imagery taken during low water. The echogram image warp and
overlay for the concept illustration was done with the Mesh Warp tool in Corel PaintShop Pro
2023.
All acoustic data processing was done with Echoview Version 13.1., in part automated with
COM automation developed in Visual Studio 2022. For additional details on the Echoview analysis
see below. In addition, Microsoft Excel was used for higher level summarization, data examination
for quality assurance and control, and final preparation of charts and tables.
Echoview data screening
For high-level identification of possible smolt passage events, we processed data collected
with up-looking transducer T4. We chose T4 because, from our preliminary review, we had
determined that it had the best echogram covering one of the highest smolt passage rates. T4 data
was auto-processed for organizing data files into day folders, creating one Echoview EV file per
day and loading all corresponding T4 data files into the EV file. This step was followed by a fast
manual review and manual adjustments of the surface exclusion line that is needed to exclude
surface echoes from the analysis. After this manual interactive step, the data was sent back through
the automation for echo integration over 1 h by 0.2 m depth increments. One of the metrics
provided by the echo integration is the area backscattering cross-section (ABC), which is
proportional to density of targets (targets/m2) in the horizontal cross-section of the beam. This
measure was tabulated in Excel, with conditional formatting (colored by ABC) providing a first
indication of when smolt passage events may have occurred.
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Echoview process for smolt density
All acoustic data were processed with a volume back scattering strength (Sv) threshold that
produced the best contrast between smolts and background: side-looking data at -44 dB; up-
looking data at -36 dB. Side-looking data showed a background of bottom and surface interference.
Beyond 70 m the interference was dynamic and so severe that we could not separate it from smolt
signals. We therefore limited the analysis to a maximum range of 70 m. For static background
noise (straight lines on the echogram), we used a set of advanced operators to subtract the average
Sv of manually selected areas on the echogram that were representative of static background and
smooth the data. Periods of noise (wind, rain, boat noise) were manually masked with bad data
regions that were subsequently excluded from the analysis. The result was run through Echoview’s
school detection algorithm in a semi-interactive process (school detection steered with manually
drawn boxes to areas where we visually detected smolts on the echogram; this minimizes the
amount of editing that needs to be done afterwards, i.e., removal of false school detections). Echo
integration was executed over the background subtracted smoothed echogram, masked by the
school detections (data outside of the school detections set to -999 dB, which translates into 0
smolts) with an echo integration cell size of 1 h by 5 m (across river).
For up-looking data the process was simpler because, here, the data did not contain static
background noise that we could have removed. So, there were only two simple steps that had to
be done interactively: adjusting the surface exclusion line (which had to be shifted up as the water
level increased over the study period) and masking periods of noise (wind, rain, boat noise). Up-
looking data were echo integrated with a cell size of 1 h by 0.3 m (depth strata starting at the water
surface). Note, the original intent was to stratify the echo integration by 0.2 m depth increments.
We revised the vertical extent to 0.3 m because it was relayed to us that the water velocity data
would be provided in 0.3 m increments. We do not expect this small difference in vertical
stratification to make a noticeable difference in the results.
Conversion from
As part of the echo integration process, Echoview calculates an area backscattering
coefficient (ABC) for each cell. The ABC is a linear measure of the energy returned from a given
volume of water that is equivalent to the total backscattering cross-section bs (m2) of all targets
(here: smolts) in the volume per cross-sectional area (m2). Divided by the mean backscattering
cross-section of individual smolts, it provides an estimate of the mean smolt density per area
(smolt/m2) within the echo integration cell:
= (1)
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In this study the physical size of the smolts was unknown. We therefore scaled the ABC to
an arbitrarily chosen total physical length of 11 cm (here referred to as “standard smolt”), which
converts to an acoustic size (bs) of 3.6E-05, based on an empirical equation that relates physical
fish size to dorsal aspect acoustic size (Love 1971). Given the cylindrical shape of the smolt swim
bladder (main reflector of sound at this frequency), one can expect the acoustic size of smolts in
dorsal aspect to be similar to that in ventral aspect. Dorsal aspect acoustic size is thus a suitable
scaling constant for echo integration of up-looking sonar data. For side-looking data, we do not
have sufficient information to derive an independent scaling constant. Several observers have
commented that they have seen smolts sail down the river, i.e., oriented broadside to the current.
So, the side-looking sonar may be seeing smolts in a variety of aspect angles, including broadside,
any degree of oblique angle, or even head-on or tail-on. Our solution to this issue was to simply
scale the side-looking estimates by a constant that produced a good overall match with (concurrent
collocated) data from the three up-looking transducers (T2, 3, 4) whose coverage fell within the
effective range of the side-looking beam.
Conversion from smolt density to smolt passage rates
The smolt density derived from the echo integration is an estimate of the mean smolt
density per area (smolt/m2) in the circular cross-section (i.e., perpendicular to the acoustic axis),
over the integration interval. When converting smolt density estimates to passage rates, the
geometry of this cross-section has to be considered in the context of the smolt density pattern. For
the up-looking sonar, the reference plane of the area density is horizontal, i.e., in the plane where
the smolt distribution is random (at least over the scale sampled) and can thus be expected to result
in a cumulatively uniform distribution over the integration interval of 1 hour (at least on average).
In this case, the density within a circle (beam cross-section) is the same as the density within a
rectangle, which means the area density (smolt/m2) can be simply multiplied by the distance
travelled (smolt speed; here water velocity used as a proxy) to obtain passage rates within a 1 m
wide section across the river (within the range, i.e., depth interval of the integration cell).
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For the side-looking sonar, the circular beam cross-section is vertical and thus in the plane
where the smolt distribution is not uniform. This makes the conversion from the (hourly) measured
density to passage rate more complicated because the density is measured within the circular beam
cross-section, which is different from the density in a rectangle of equal height. Compared to a
rectangle, the circular beam cross-section under samples the top and bottom layers (0.3 m depth
strata), while oversampling the center layers. To take this into account, we first converted smolt
density to the number of smolts in the circular cross-section at side-looking range bin i:
=× (4)
The second piece of the puzzle is to convert the estimated real-world vertical smolt
distribution obtained from the up-looking sonar dataset to the relative vertical distribution seen
within the circular cross-section of the beam. Since the acoustic beam spreads with range, its cross-
section increases with range, which in turn changes the relative vertical distribution of smolts
within the beam as a function of range (Figure 3). To convert the vertical smolt distribution to the
distribution seen within the circular beam cross-section, we had to determine the area of each circle
segment for each depth stratum and range bin. To do this efficiently we used ArcGIS 10.2 to draw
circles corresponding to the beam cross-section for an effective beam width of 2° for each 5 m
range bin, then used the split polygon function to perform an intersect operation between each
circle and the set of horizontal lines representing the 0.3 m depth strata. The result was a table with
area measurements for each circle segment.
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Figure 3 Vertical smolt distribution as a function of the shape, size, and position of the reference
area. The example shown is based on a 6°side-looking beam and 0.2 m depth layers. In our study,
the side-looking beam is 2°and vertical stratification is by 0.3 m depth increments. Nevertheless,
the same principle applies. The real-world smolt distribution is referenced to a vertical rectangle
(top left). The relative distribution seen within the side-looking beam changes as a function of
side-looking range. Two examples are shown: range 4 m (bottom left) and 8 m (bottom right).
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We now used the ratio of each circle segment’s area to that of a 1 m x 0.3 m rectangle to
derive a weighting factor with which to multiply the real-world vertical smolt distribution
expressed as a set of absolute numbers scaled to a total of 100 smolts (e.g., 44% = 44 smolts) to
obtain the distribution (expressed as absolute numbers) within the circular beam cross-section of
each range bin. Note, in this step, the distribution has to be expressed in absolute numbers, rather
than percentages, because we are switching between reference frames (from rectangular to
circular). Summing up the absolute numbers seen within each circle segment (intersection between
circular beam cross-section and depth layer) provides the basis for the relative distribution within
the circle, with:
= (5)
In the next step, we used this range specific distribution within the circular beam cross-
section to allocate Sa,i (mean number of smolts seen in the circular cross-section in side-looking
range bin i) to their depth strata:
= × (6)
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Now that the number of smolts derived from the side-looking echo integral have been
allocated to their depth bins, we can convert the number of smolts seen in the circular cross-section
to the number of smolts in a rectangle, normalized to a rectangle 1 m downriver, beam diameter in
height, which will then be easy to convert to a passage estimate.
= (× .) (7)
This normalized number of smolts Ni can now be multiplied by the distance smolt travel
downstream in 1 hour to provide an estimate of smolt passage, i.e., the number of smolts that
travelled through the side-looking range bin i in the given hour.
For additional details and illustrations see Mueller 2022.
For this study, water velocity was used as a proxy for smolt velocity. Water velocity
measurements were extracted from ADCP data collected on 2023-05-21. While the ADCP data
collected on 2023-06-21 would have been closer in time to some of our sonar data, we were not
able to match its river profile to our transducer locations. Given the resulting spatial uncertainty,
we chose to instead use 2023-05-21 water velocity for the entire Tier 1 analysis.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
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Nushagak Cooperative, Inc. 12 December 2023
Results and Discussion
In the initial setup, all up-looking transducers were run with the shortest possible pulse
duration (0.033 ms). In our review of the initial data collected, we noticed that the three
up-looking transducers located in shallow water (< 2 m depth), T1, T7 and T8, did not provide
effective coverage for smolt monitoring because excessively long ring-down signals (extending
well over > 1 m range) drowned out any echoes received from the shallow water column. To
remedy this problem, we changed the pulse duration for T1, T7 and T8 from 0.033 ms to
0.130 ms. This reduced the range extent of the ring-down of T7 and T8 to 0.8 m, which cleared
the top 0.5 m of the water column for T8, and the top 0.7 m of the second bounce window in the
T7 echograms, which we deemed sufficient to at least qualitatively determine whether or not
significant smolt passage occurs at the locations of these two transducers. T1 data, however, still
showed ring down signals extending over 1.3 m, despite the longer pulse duration, which rendered
T1 data unusable.
Up-looking transducers T2, T3, T4, T5 and, with the longer pulse duration, T7 and T8
produced good echograms for smolt analysis. T6 was somewhat compromised by its poor aim (30°
tilt downstream), which is very difficult to rectify once the up-looking transducer string is
deployed. Given the uncertainty how useful its data will be, we have so far only analyzed one day
of its data (2023-06-20; see below). For this day, its estimate is consistent with the general cross-
river distribution pattern.
Given the extremely large acoustic data volume acquired in this study (1 TB), it was critical
to develop an efficient data analysis strategy since brute force analysis of every byte recorded is
generally an inefficient use of resources and beyond the budget of this project. Efficiency often
hinges on a good screening method that can be used to quickly identify the most valuable portions
of the data. In the context of this study, valuable means providing meaningful information on the
spatial-temporal distribution of smolt passage through the site. For this purpose, we used a highly
automated echo integration procedure with interactive supervision limited to manual adjustments
of the surface line used to exclude surface echoes from the analysis. The results of this screening
provide a good synopsis of the data (Figure 4 and Figure 5) that indicated a stretch of very clean
data with a high likelihood of smolt passage events from May 29th – June 3rd. Additional days of
likely smolt passage events include June 20th – 23
rd, July 1st, 2nd and 4th. Several contiguous hours
of high backscatter values mostly in the top third of the water column, gradually ramping up and
down, are a good indication of a smolt passage event. Elevated backscatter values extending further
down in the water column creating more diffuse patterns are often wind or rain related noise; short
spikes in single hours are often noise events related to boat wakes. It is important to note that these
screening results were generated in a highly automated process that does not include noise editing.
So, there is a fair amount of ambiguity during periods of rain and wind. This does not mean that
noisy stretches may not also have periods that would lend themselves to smolt analysis, it just
means that they will require more labor-intensive analysis.
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Nushagak Cooperative, Inc. 15 December 2023
The second part of our strategy was to approach the analysis in a tiered fashion, starting
with a detailed analysis of a first subset (Tier 1) before deciding on how to proceed. For this first
subset we selected from the screening results 6 days with the cleanest, most conclusive looking
data: May 29th – June 3
rd and June 20th. For this interim report we have completed Tier 1 analysis,
with the exception of up-looking transducer T6 (tilted transducer), for which we have analyzed
only June 20th.
Side-looking data showed a background of bottom and surface interference. Beyond 70 m
the interference was dynamic (shifting in range from ping to ping) and so severe that we could not
separate it from smolt signals. We therefore limited the analysis to a maximum range of 70 m. We
also limited the analysis to a minimum range of 20 m because at ranges < 20 m, the side-looking
2° beam is too narrow to cover the top m of the water column (Figure 2). Within this 50 m range
window (20 – 70 m), we were pleased with the results of the background subtraction and school
detection algorithm (Figure 6), with the caveat that the background subtraction may introduce a
low bias in smolt estimates in the 65 – 70 m range bin, as indicated by the blank horizontal band
running through the large school in the right third of the echogram excerpt shown in Figure 6.
The side-looking echograms provided a fascinating picture of individual schools.
Conceptually, echograms of moving objects, collected with a stationary transducer, can be
translated into a 2D spatial picture, using the speed of the object as a conversion factor to convert
time (x-axis of a standard echogram) to space. Figure 7 shows an example of what this looks like.
The meanders that we introduced into the draped echogram are intended to only indicate that, in
the real world, smolt schools do not move in a straight line but shift to some degree from side to
side. Outside of the sonar coverage, we do not know the actual trajectories of the smolts shown or
how individual schools morphed over the amount of space shown. But, assuming the smolts were
travelling at approximately 1 m/s, the graphic is a good representation of the approximate spatial
extent of their schools and the spacing between schools. If the smolts had been travelling more
slowly, one would have to imagine the draped echogram contracted along the lines, which would
reduce their spatial extent and spacing along the river. Conversely, if smolts had been travelling at
a faster speed their spatial extent and spacing would be larger than shown. With an assumed smolt
speed of 1 m/s, the large schools seen on June 20th extended tens of meters downriver and about
10 m cross-river. Note, the cross-river extent is derived from the range measurement, which is very
precise and independent of the smolt travel speed.
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Nushagak Cooperative, Inc. 16 December 2023
Figure 6 Example of side-looking sonar data before (top) and after (bottom) cleaning. The
echograms plot the acoustic data as volume backscattering coefficient (Sv) in range (increasing
bottom to top) over time (progressing left to right). The excerpt shown covers a 50 m range
window from 20 – 70 m, over 1.5 minutes (2023-06-20 18:07:52). The original echogram shows
smolt schools of varying sizes superimposed on a pattern of straight lines created by echoes
from static background (mostly generated by sidelobes hitting the river bottom and/or surface).
On the clean echogram the background has been removed leaving only smolt echoes. The
cleaning effect was achieved through the sequential application of 1) static background
subtraction, 2) convolution filter and 3) Echoview’s school detection algorithm. The resulting
clean data were run through echo integration analysis to derive estimates of smolt density.
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FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 18 December 2023
Each of the two sonar configurations, side- and up-looking, provides valuable information
that the other one does not. Side-looking data covers a large continuous stretch across the river,
giving insights into the size, shape and spatial distribution of smolt schools. It can also inform us
about smolt passage between the small footprints of the up-looking transducers. However, one of
the downsides of the side-looking sonar is that it cannot provide good information on the vertical
distribution of smolts or vertical extent of their schools. Vertical information is best obtained with
up-looking sonar, where depth aligns with range and is thus highly resolved in the data. Figure 8 -
Figure 11 show examples of up-looking echograms of smolts that provide a high-resolution view
of their vertical distribution and dynamic schooling behavior.
For the quantitative results of the analysis, we are presenting the time series of smolt
estimates obtained with the three up-looking transducers (T2, T3 and T4) that were within the
effective range of the side-looking sonar and compare them to the estimates obtained from the
corresponding 5 m range bin of the side-looking data (Figure 12). The paired time series are in
reasonably good agreement considering the side-looking estimates are from 5 m bins (5 m across
the river), and the amount of smolt passage variation one could expect within this space. The three
locations also correlated. All three show passage rates on June 20th that were about 10 times as
high as on any of the other 6 days (May 28th – June 3
rd) in the Tier 1 dataset. The side-looking total
estimate for June 20th (5.2 million smolt passage proxy counts) is an order of magnitude higher
than the totals for May 29th – June 3rd combined (<0.5 million). The complete results, including
transducers not shown in the time series plot, will be delivered as an Excel xlsx workbook and
presented at the ISR meeting in December of 2023.
Up-looking estimates of smolt passage are referred to as standard smolt passage rates; and
side-looking estimates of smolt passage as smolt passage proxy counts. We draw this distinction
to recognize the fact that there is more uncertainty in the relationship between side-looking
estimates and absolute (true) smolt passage rates (actual smolts/h) than for up-looking sonar. For
up-looking data, there are only two pieces of information missing that separate these estimates
from estimates of absolute passage rates: physical smolt size and smolt speed. Smolt size
information is needed to scale the total amount of echo energy (echo integral) by the average
amount of energy reflected by an individual to estimate smolt density (precursor to smolt passage).
For sonar applications that see fish in dorsal or ventral aspect (i.e., from above or below), the
average amount of energy reflected by an individual can be derived from well-established
empirical relationships between physical fish size and acoustic size (Love 1971). Since we did not
have information on the actual size of the smolts that out-migrated over our study period, we
arbitrarily chose a total physical length of 11 cm for our “standard” smolt. This value falls well
within the range of sizes that have been reported over the years for the Kvichak River (Bures et al.
2018).
For side-looking data, there is the added complication that the acoustic size is even more
uncertain. Several observers have commented that they have seen smolts sail down the river, i.e.,
oriented broadside to the current (Hughes and Kelly 1996). The side-looking sonar may be seeing
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FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 19 December 2023
smolts broadside, at any degree of oblique angle, or even head-on or tail-on. Our solution to this
issue was to simply use the relationship between (concurrent and collocated) up- and side-looking
estimates in lieu of an acoustic size estimate, to derive a scaling constant. This constant came out
to 5E-06, i.e., one order of magnitude smaller than the dorsal aspect size. This is a plausible value
given that the cross-sectional area of a cylindrical swim bladder in head or tail aspect is much
smaller than its cross-section in dorsal or ventral aspect.
The second piece of information that introduces some amount of uncertainty is smolt speed.
We used water velocity as a proxy. This has been seen as generally acceptable throughout the
Bristol Bay Science Research Institute (BBSRI) smolt program, based on a 3-D video tracking
study (Hughes and Kelly 1996). More recent video work on the Chilko River, British Columbia,
supports the conclusion that water velocity is a reasonable approximation of smolt velocity
(Mueller 2022). As described previously, we used water velocity measurements extracted from
ADCP data collected on 2023-05-21. This applies equally to side- and up-looking estimates.
The potential bias associated with conventional echo integration of targets that are not
uniformly distributed in the circular beam cross-section was deemed negligible given the sampling
scenario (2° beam width, < 100 m maximum range, vertical smolt distribution) (Mueller et al.
2006).
The caveats described above do not significantly affect conclusions regarding the relative
distribution patterns over shorter periods of time. Given its much larger smolt sample size, we
focused on data from June 20th to highlight some of these patterns and further assess the
consistency between side- and up-looking sonar estimates. Figure 13 compares the cross-river
distribution of smolt passage estimates obtained with the series of up-looking sonars and those of
the spatially continuous data obtained from the side-looking sonar, partitioned into 5 m range bins.
Similar to the entire Tier 1 time series, up-looking transducers T2, 3 and 4 show good relative
agreement with the nearest side-looking range bin. It is worth noting, however, that the peak of the
side-looking estimates falls between 45 m and 55 m range, an area that is not covered by the up-
looking transducers. Transducers T5, 6, 7 and 8 are beyond the side-looking sonar’s effective
range. Their low smolt estimates continue the decrease in passage rates seen at the far end of the
side-looking sonar.
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Nushagak Cooperative, Inc. 24 December 2023
Overall, the pattern we see here is consistent with the sockeye smolt passage patterns that
we have seen over 20 years in various Bristol Bay rivers (Bures et al. 2018, Mueller 2021) and, in
more recent work in the Chilko River (Mueller 2022). The bulk of sockeye salmon smolt passage
tends to occur in the thalweg, the area of the fastest flow. (One exception to this rule is that in some
studies observed movement towards shore around sun rise can occur, but this movement pattern
typically took place towards the tail end of night passage events.)
Smolt cross-river distribution, parsed by hour, is shown in Figure 14, which also shows
water velocity information for comparison. Parsing the data by hour reveals that 30% of this high
passage day occurred over just two hours: 18:00 – 20:00. Figure 15 shows the same information
in a different format with the aerial image for a spatial, real-world reference. The up-looking data
shows a similar spatial temporal pattern: highest hourly passage 18:00 – 20:00, with lower passage
rates occurring from 07:00 – 15:00 (Figure 16).
The last two figures (Figure 17 and Figure 18) present the vertical cross-river distribution
parsed by time of day. While the vertical smolt distribution is always skewed towards the surface,
from midnight to 06:00, that skewness is more pronounced. During this timeframe 51% of smolts
are in the top 0.3 m, compared to 26% during daylight hours. This is also consistent with the
sockeye smolt patterns observed in other Bristol Bay river systems.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 26 December 2023
Figure 15 Cross-river distribution of smolt passage proxy counts by hour obtained from side-
looking sonar data (2023-06-20) with spatial real-world reference. Data series randomly colored by
hour. Side-looking sonar coverage is mapped as 2°cone (light red overlay over aerial image).
Placement of up-looking sonars indicated by green circles.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 30 December 2023
Suggestions for additional data analysis:
With the Tier 1 work presented here, we have completed the analysis of 7 data days (with
the exception of T1, which was not usable, and T6 which we processed only for June 20th).
Additional resources could be spent on 1) processing 6 more days of high resolution smolt data
(the work equivalent of 1 data day was diverted to the screening analysis), as intended earlier, or
2) developing a run time index (i.e., full review with noise masking T4 May 25th – July 11th) and
full analysis of approximately 4 more data days.
Recommendations for Year 2 field work:
Examine existing LIDAR bathymetry TIN for possibly better sonar locations in the
immediate vicinity of the 2023 location. We have the tools to pull profiles from TINs on
the fly and thus quickly examine how the river profile changes with small shifts up- or
downstream. A few meters up- or downstream can make a significant difference in the
shape of the water column that needs to be ensonified with minimum interference from
echoes reflected by boundaries. It is possible that a slightly different location would provide
a longer unimpeded view for the side-looking 2° beam, and possibly deeper water for the
right bank up-looking transducer T1.
If better coverage along the right bank is important (e.g., because this is the side where the
intake of the proposed hydroelectric facility would be), consider removing transducer T1
from the daisy chain of up-looking transducers and instead mount it in a side-looking
fashion on an independent mount to supplement the side-looking 2° data with better
nearshore coverage.
Take periodic low altitude drone images (aimed straight down) throughout the study period
for verification of transducer locations and aim.
Nuyakuk River Hydroelectric Project Fish Community and Behavior Study
FERC No. 14873 Initial Study Report – Appendix A-2
Nushagak Cooperative, Inc. 31 December 2023
References
Barange, M. 1994. Acoustic identification, classification and structure of biological patchiness
on the edge of the Agulhas Bank and its relation to frontal features. South African Journal of
Marine Science, 14: 333-347.
Bures, J. W., Priest, J. T., Burril, S. E., M. R. Link, Degan, D. J. 2018. Sockeye salmon smolt
abundance and inriver distribution: results from the Kvichak, Ugashik, and Egegik rivers in
Bristol Bay, Alaska, 2016. Report prepared by the Bristol Bay Science and Research
Institute, Dillingham, Alaska.
Hughes, N. F., and L. H. Kelly. 1996. New techniques for 3-D video tracking of smolt swimming
movements in still or flowing water. Canadian Journal of Fisheries and Aquatic Sciences
53:2473–2483.
Love, R. H. 1971. Dorsal-aspect target strength of an individual fish. The Journal of the
Acoustical Society of America 49(3): 816-823.
Mueller, A.M. 2021. Obtaining acoustic estimates of smolt passage — Discussion. Report
prepared by Aquacoustics LLC for the Bristol Bay Science and Research Institute,
Dillingham, AK.
Mueller, A. M. 2022. Estimating Chilko River sockeye smolt abundance with sonar – 2022.
Report prepared by Aquacoustics LLC for Fraser River Stock Assessment, Fisheries and
Oceans Canada.
Mueller, A. M., D. J. Degan, R. Kieser, and T. Mulligan. 2006. Estimating sockeye salmon smolt
flux and abundance with side-looking sonar. North American Journal of Fisheries
Management 26: 523-534.
INITIAL STUDY REPORT
ATTACHMENT B: NUYAKUK FALLS FISH PASSAGE STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, Alaska 99576
December 2023
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 3
4.0 METHODOLOGY ............................................................................................................. 4
4.1 Two-Dimensional HEC-RAS Model Development............................................... 4
4.1.1 Hydrologic Data.......................................................................................... 5
4.1.2 Define Species Migration Periodicity......................................................... 8
4.1.3 Conduct Modeling and Evaluate Potential Effects of Project Operations ... 8
4.1.4 Field Data Calibration................................................................................. 9
4.1.5 Stage-Discharge Curve ............................................................................. 12
4.1.6 Two-Dimensional Model Calibration ....................................................... 12
4.2 Agent-Based Model Development........................................................................ 12
4.2.1 Agent-Based Model Development Methods............................................. 12
5.0 RESULTS ......................................................................................................................... 16
5.1 Two-Dimensional Model Development Results................................................... 16
5.2 Agent-Based Model Development Results ........................................................... 16
6.0 DISCUSSION AND FINDINGS...................................................................................... 16
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 16
7.1 Two-Dimensional Model Variances ..................................................................... 16
7.2 Agent-Based Model Variances............................................................................. 17
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 17
8.1 Two-Dimensional (2D) HEC-RAS Model Development ..................................... 17
8.2 Agent Based Model Development ........................................................................ 17
9.0 STUDY-SPECIFIC CONSULTATION ........................................................................... 18
10.0 REFERENCES ................................................................................................................. 18
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. ii December 2023
LIST OF FIGURES
Figure 3-1. The 2D model study area. .............................................................................................4
Figure 4-1. Nuyakuk April 2023 LiDAR bare earth digital elevation model data relative to
the model boundary..................................................................................................7
Figure 4-2. Locations in the Falls Reach of the Nuyakuk River in which Solinst Level
Loggers and a Solinst Baro-logger were installed to monitor WSE and
barometric pressure................................................................................................10
LIST OF TABLES
Table 4-1. Transducer and baro-logger installation summary, Nuyakuk River, Alaska. ..............10
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. iii December 2023
ACRONYMS AND ABBREVIATIONS
2D Two-dimensional
ABM Agent-Based Model
DEM Digital Elevation Model
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ft foot
IRA Integrated Risk Assessment
ISR Initial Study Report
kCal kilocalorie
LCM Life Cycle Model
LiDAR Light Detection and Ranging
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
TM Technical Memorandum
USFWS U.S. Fish and Wildlife Service
USGS U.S. Geological Survey
USR Updated Study Report
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
Project development and associated water diversion operations may impact multiple life stages
and species of fish. The Cooperative has chosen a conceptual and analytical framework approach
that describes the likely relationships of those impacts on fish and their habitat. Conceptually,
this includes both adult and juvenile fish passing upstream and downstream through the Project
Area, and the potential interactions between those components. For salmon, although a
substantial portion of their life history takes place outside the Project Area, the health and vitality
of the life stages when they are within the Project Area can influence the overall population
viability. The framework includes the necessary analytical tools comprised of technical studies,
models, mathematical equations, metrics, and the underlying assumptions that will be applied to
quantitatively and/or qualitatively define potential Project effects.
One key tool in the overall assessment is the development of a two-dimensional (2D) hydraulic
model that extends from approximately 1,000 ft (0.19 mi) upstream of the powerhouse intake to
1,400 ft (0.27 mi) downstream of the powerhouse tailrace (4,310 ft or 0.82 mi total). The 2D
model will be used to assess hydraulic and fish habitat changes within the Nuyakuk Falls and in
proximity to the in-river Project structures. The model horizon extends over the anticipated life
of the Project and will be developed for the following flow conditions: 1) current, with Project;
2) current, without Project; and 3) future flows related to climate change.
A second primary tool in the assessment of potential Project effects is the development of an
Agent-Based Model (ABM) to evaluate the behavior of upstream migrating adult salmon relative
to the hydraulic conditions in the Falls Reach. The ABM combines input from both the 2D
hydraulic model, results of the radio telemetry assessment of in-river adult salmon migration
behavior, and extensive literature review and input from stakeholders to model fish passage at
the Falls under baseline and Project operations.
Development of baseline model scenarios occurred in Study Year 1 (2023). In Year 2 (2024), the
Cooperative will use the models to run operational and climate change flow scenarios. The
combined results of both flow and fish behavior will allow for the understanding of potential
changes in fish passage conditions and evaluate how changes in depth and velocity may translate
to changes in fish passage efficiency. In turn, this information will be used to evaluate potential
flow-related effects on fish populations as described in the Life Cycle Model (LCM) and
Integrated Risk Assessment (IRA) studies.
2.0 STUDY GOALS AND OBJECTIVES
The primary goal of this study is to evaluate how potential Project-related flow changes may
impact fish passage (positively and/or negatively) through the Falls Reach.
Five objectives are listed below that define the major focus of this study:
1. Identify primary upstream and downstream fish passage corridors and hydraulic
conditions within the cascade/Falls Reach of the study area (i.e., proposed bypass reach)
and their flow sensitivities under current conditions and proposed Project operations as it
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 2 December 2023
relates to potential for stranding, predation risk, migration delay, and passage conditions
(negative or positive) under different flow scenarios.
2. Estimate species-specific flow windows for successful upstream fish passage through the
Falls Reach that include upper and lower passage thresholds above and below which
passage may be improved, impaired, migration delayed, risk or predation increased, or
seasonal timing affected.
3. Identify potential areas that may be susceptible to fry and juvenile stranding and trapping
within the proposed bypass reach due to Project induced flow fluctuations (ramp-up and
ramp-down).
4. Evaluate potentially positive and negative effects of proposed Project operations and flow
releases on adult upstream and fry/juvenile/smolt downstream fish passage and potential
stranding and trapping of fish.
5. Identify potential alternative operations or refinements to operations that facilitate
upstream and downstream passage and minimize/eliminate the risk of stranding and
trapping.
These objectives revolve around the resolution of a series of questions associated with how
Project operations may affect fish passage conditions within the Falls Reach. Specific questions
to be addressed include:
1. Would flow-related changes in depth and velocity and habitat composition impair or
improve upstream fish passage conditions as compared to species-specific criteria?
2. Would flow-related changes in total available habitat for upstream passage result in
increased, decreased, or stable densities of fish in the Falls Reach to the point that
density-dependent effects are detectable?
3. Would flow-related changes in depth and velocity and habitat composition impair or
improve downstream fish passage conditions as compared to species-specific criteria?
4. Would flow-related changes in total available habitat for downstream passage result in
increased, decreased, or stable densities of fish in the Falls Reach to the point that
density-dependent effects are detectable?
5. Would hydraulic conditions be created that could improve or delay the upstream passage
of adult salmon?
6. Would hydraulic conditions be created that could improve or delay downstream passage
of juvenile salmon?
7. Would flow-related changes in the Falls Reach positively or negatively alter depth and
velocities in fish rearing habitats or change the quantity, composition, or configuration of
the rearing habitats?
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 3 December 2023
8. Would rapid changes in flow dewater fringe habitat/passage corridors resulting in
potential fish stranding or trapping zones?
9. Would operational flow changes have the potential to dewater or scour spawning habitats
immediately downstream of the Falls and tailrace?
Potential impacts would be centered around the Project footprint that encompasses Nuyakuk
Falls and would be associated with a flow reduction. These flow alterations would change the
prevailing hydraulic parameters and could lead to improved, negative or unchanged conditions in
migration pathways and resting/rearing habitats. Upstream and downstream passage success and
survival may be reduced due to unsuitable passage conditions, shortened passage windows,
delay, increased predation, etc., or improved if more suitable conditions and longer passage
windows are provided that decrease passage times and energy expenditures of fish. The flow
regulation may also alter habitats used by resident fishes.
This evaluation employs the use of two models: 1) the development and application of a
HEC-RAS 2D hydraulic model to define the reach hydraulics: and 2) linking the 2D model
outputs with an ABM to evaluate passage success under different flow scenarios.
3.0 STUDY AREA
The geographic focus of the fish passage evaluation will extend from approximately 2,640 ft (0.5
mi) upstream of the upper end of Nuyakuk Falls to approximately 1,400 ft (0.27 mi) below the
lower end of the Falls; total length of the study area is approximately one mile (Figure 3-1). The
distance upstream of the proposed intake location reflects a reasonable distance to characterize
the flow field as water approaches the Falls and proposed diversion location. Overall, the study
area for 2D hydraulic modeling encompasses the longitudinal distance for both the Fish
Entrainment and Impingement Study and the Assessment of False Attraction at the Proposed
Tailrace Study. The extent of the study area may be modified based on review of the light
detecting and ranging (LiDAR) data and preliminary results from the 2D model.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 4 December 2023
Figure 3-1. The 2D model study area.
4.0 METHODOLOGY
Study methods during Year 1 (2023) were consistent with those specified in the Revised Study
Plan (RSP) with the initial work focused on collecting water surface elevation (WSE) data and
model development. Model calibration is ongoing and model runs for different flow scenarios
will be completed during Year 2 study efforts.
4.1 Two-Dimensional HEC-RAS Model Development
A 2D HEC-RAS version 6.3.1 model was developed to evaluate the existing and future
conditions of the Falls Reach of the Nuyakuk River.
This model will provide fine scale detailed information such as depth and velocities (magnitude
and direction) within each of the migration pathways and will enable the computation of other
variables relevant to both fish passage and Habitat Suitability Criteria (HSC) above and below
the Falls Reach itself. The model will be calibrated using field data including various WSEs that
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 5 December 2023
were surveyed to provide ground truthing to the remote LiDAR imagery, discharge
measurements, and WSE measurements.
Level loggers recorded both water stage and temperature over the range of flows occurring
during the upstream and downstream migration periods of salmon. The level logger data was
useful in determining localized stage changes over a range of flows that can be used in refining
model predictions for those locations during ongoing model development. The calibrated model
will then be used to model passage conditions under different flows.
4.1.1 Hydrologic Data
To evaluate future hydropower potential and impacts on fish habitat, the Cooperative requires
projected flows for the Nuyakuk River reflecting the future climate conditions in the mid-century
and late century. The Cooperative’s hydrology for the present-day condition is based on the
flows from the United States Geological Survey (USGS) gage #15302000 (Nuyakuk River near
Dillingham, Alaska), located about 4.6 river miles west of the Project site. The gage currently
has daily flow records from 1953 to the present but has large data gaps where flow is not
reported, particularly in the 1990s. The Cooperative will evaluate model scenarios including
calibration flow conditions, existing average monthly flows, and future condition average
monthly flows.
4.1.1.1 Light Detection and Ranging (LiDAR)
2020 LiDAR data was collected on May 14, 2020, using a specialized flight plan with a target
point density of 6.0 points/m2. The LiDAR survey was accomplished using a Riegl VQ-880-
GII mounted in a Cessna Caravan. Additionally, aerial imagery was acquired on the same flight
using a PhaseOne iXU-RS1000 digital camera. Ground survey points were acquired to post-
process and calibrate the LiDAR data. The LiDAR survey results included the classified survey
points, as well as one-meter ESRI grids of the bare earth digital elevation model (DEM) and the
highest hit of the digital surface model (DSM). Additionally, a digital imagery mosaic was
created using the aerial photographs.
For additional information on field collection and Quality Assurance/Quality Control (QA/QC)
of the 2020 LiDAR, please refer to the Nuyakuk River Topobathymetric LiDAR Technical Data
Report (Quantum Spatial 2020).
4.1.1.2 Terrain and Data Sources
The terrain used in the 2D model was created from two sources of site-specific topo-bathymetric
LiDAR data. The first LiDAR dataset in 2020 was collected under high flow conditions thereby
limiting the ability to collect accurate bathymetric data in some of the high velocity/turbulent
portions of the Falls Reach channel. An additional LiDAR flight was conducted in April 2023
under lower flow conditions with the goal of filling in these topo bathymetric data gaps. Lastly, a
final LiDAR dataset was collected in late June 2023 to capture snow-free conditions in the
floodplain. The elevation data from the 2023 flights will be merged with the elevation data from
the 2020 flight to create a single terrain layer used as the basis for the 2D model described in this
section. The dataset merging will be completed using the best engineering judgment based on the
quality and availability of each dataset. Figure 4-1 shows the April 2023 LiDAR dataset
compared to the model boundary.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 6 December 2023
4.1.1.3 Two-Dimensional Areas
The model domain is roughly 3,100 meters long and extends roughly 1,200 meters upstream and
1,200 meters downstream of the Falls. The model has a default cell size of 10 meters with the
Falls portion of the model using 0.5-meter cells. In total, the modeling domain contains just over
1 million computational cells. Additionally, some initial model runs applied 1-meter cells in the
Falls portion to improve model run times before the calibration data were available for use. The
0.5-meter cells are expected to provide adequate information for the fish behavior ABM;
however, it is possible that larger cells may capture the same flow patterns. The final cell size
used in the model may be dependent on the calibration of the hydraulic model as will be further
described in the Updated Study Report (USR). Any required adjustment to the model cell size
will be discussed amongst the entire Nuyakuk modeling team before implementation.
4.1.1.4 Model Energy Loss and Computational Equation Type
The energy losses to flow within the model boundary are a function of channel roughness,
channel form loss, and turbulence/mixing within the Falls Reach. In order to accurately represent
the energy loss present in the Falls Reach, the Full Momentum or shallow water set of equations
will be used for the simulations. Manning’s n roughness values in the model are currently set to
the model default value of 0.06. Final Manning’s n roughness values will be decided after model
calibration. Assumed channel roughness is expected to range from 0.035 to 0.07 depending on
the observed/assumed channel substrate and channel form loss. Turbulence or mixing loss within
the model will be included by using the Non-Conservative turbulence model and default mixing
coefficients of 0.3 (Longitudinal) and 0.1 (Transverse).
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 8 December 2023
4.1.1.5 Boundary Conditions
The boundary conditions for the 2D model will be based on the site-specific rating curve being
developed for the project location and the measured energy grade slopes of the channel bed. The
upstream model boundary will use an unsteady flow hydrograph condition based on measured or
assumed flows and an energy grade slope of 0.00019. The downstream model boundary will use
a normal depth slope assumption. The downstream normal depth slope is currently set to 0.00019
but may be adjusted during model calibration.
4.1.2 Define Species Migration Periodicity
The migratory life histories of several fish species in the Nuyakuk River involve the upstream
migration of adults seeking suitable areas for spawning, and the downstream migration of fry,
juveniles, and smolts to the ocean. The timing and duration of these migrations vary by species
and life stage but in general, coincide with the hydrologic characteristics of a given watershed.
Thus, both upstream and downstream migrations tend to occur during periods of increasing or
relatively high flows and infrequently during low flow periods. Because proposed Project
operations will occur throughout the year, the extent to which the operations may affect upstream
and/or downstream migration success will depend on the timing of those migrations and
prevailing flows. Most of this information for the Nuyakuk River will be compiled as part of
Attachment A. – Characterization of the Fish Community and Behavior Near the Project Area.
That study also will rely on a variety of source materials from the published and unpublished
literature, as well as personal contacts with agency and stakeholder personnel with direct
experience with the fishery resources of the Nushagak River, and certain empirical data collected
on-site. For this study, the objective will be to define for each species, the periodicities of adult
upstream migration, and fry, juvenile/smolt downstream migration. This information will focus
the modeling and analysis on those periods most vulnerable to Project operational effects.
4.1.3 Conduct Modeling and Evaluate Potential Effects of Project Operations
Development of the 2D model to evaluate Project effects will begin with initial runs for flows
representative of the current baseline. The model will then be used to identify pathways suitable
for upstream and downstream migration. These areas will be longitudinally linked, thereby
depicting the most probable pathways of migration through the entire Falls Reach for unregulated
flow conditions.
The pathways identified from the 2D modeling will likely vary in physical characteristics, so
upstream passage through each will differ in the degree of difficulty. Therefore, model metrics
will be analyzed to identify and categorize pathways into groups based primarily on velocity
conditions and adult fish swimming speeds (sustained, prolonged, and burst). The model will
then be run for a series of flows that represent a range of conditions that may occur during the
migration period due to Project operations and evaluated in terms of changes in passage success
based on species-specific passage criteria.
Analysis of habitat for resident fish due to flow changes will be made based on a Physical
Habitat Simulation (PHABSIM) type analysis (Bovee 1982; Bovee et al. 1998) using
representative HSC for those species. These figures conceptually display the final endpoints of
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 9 December 2023
more detailed analyses that will be derived via 2D hydraulic modeling of migration pathways
and specific analyses of tailrace and intake characteristics.
Analysis will include the development of a suite of comparative matrices that lists the model-
generated values of each of the parameters for each of the flows (including regulated and
unregulated) and identifies probabilities of values being conducive to successful passage, and
whether they create suitable migration, rearing, holding, and spawning habitats. These types of
matrix tables will be used for identifying flow windows, which illustrate the range of flows and
their associated probabilities (likelihood estimates) under which successful upstream migration
would occur for each of the designated areas, and then for the entire reach.
The bathymetric mapping and modeling will also be used to identify potential areas of stranding
and trapping and the flows at which these areas may develop. The risk of stranding and trapping
most commonly occurs under conditions of pulse-type flows such as those associated with
hydroelectric peaking or load following. Under these types of operations, fish, in particular fry
that may be occupying relatively shallow pool areas, may suddenly become trapped within the
isolated pools. Likewise, fry occupying flat shallow water areas may suddenly become stranded.
4.1.4 Field Data Calibration
As part of the development of hydrodynamic and fish passage models for the Nuyakuk
Hydroelectric Project, 11 Solinst level logger pressure transducers (Model 3001) were installed
within the project reach of the Nuyakuk River (Figure 4-2). Data collected from these units will
be used to monitor WSE throughout the reach and detect a response in WSE to changes in river
flow. This report summarizes the installation procedures and data collection during the field
effort, as well as recommendations for recurring data downloads.
Installation occurred during the period of May 18-20, 2023 at flows ranging from 5,000-5,700
cubic feet per second as reported at USGS gage near the outlet of Nuyakuk Lake, Alaska
(#15302000). The location of each monitoring site was predetermined in consultation with
members of the 2D modeling team. Since the pressure transducers selected for use measure
absolute pressure (water pressure + atmospheric pressure), a single Solinst Baro-logger (Model
3001) was installed near the field base camp to detect variations in atmospheric pressure.
Prior to installation, all units (Level-loggers and Baro-logger) were launched and synchronized
to record data at one-hour intervals. Other datalogger information recorded included serial
number, sample mode, storage capacity, sample rate, pressure, and temperature settings.
For each monitoring site, pressure transducer installation followed a standardized procedure. A
summary of the pressure transducer installation for each site is provided in Table 4-1.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 10 December 2023
Figure 4-2. Locations in the Falls Reach of the Nuyakuk River in which Solinst Level Loggers and
a Solinst Baro-logger were installed to monitor WSE and barometric pressure.
Table 4-1. Transducer and baro-logger installation summary, Nuyakuk River, Alaska.
Site # Transducer
Serial # Transducer Type Installation
Date
Location Coordinates
Latitude Longitude
100 02033902 Water Level 05/18/2023 59.908841 -158.123246
101 02033874 Water Level 05/18/2023 59.910844 -158.120868
103 02036309 Water Level 05/19/2023 59.910904 -158.117448
104 02023471 Water Level 05/20/2023 59.912200 -158.119889
105 02036110 Water Level 05/20/2023 59.912201 -158.117276
106 02036317 Water Level 05/19/2023 59.911403 -158.119331
107 02023477 Water Level 05/20/2023 59.910588 -158.114937
108 02036083 Water Level 05/20/2023 59.910348 -158.114499
109 02033875 Water Level 05/18/2023 59.910100 -158.117544
110 02036116 Water Level 05/20/2023 59.909494 -158.113925
111 02023495 Water Level 05/18/2023 59.908052 -158.114636
Baro-logger 12034351 Barometric Pressure 05/17/2023 59.908252 -158.119962
Note: Site #102 was judged to be redundant and not installed.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 11 December 2023
Additionally, land survey professionals from Edge Survey and Design, LLC (Edge) established a
survey control point at each of the 11 WSE monitoring sites. The survey control points/bench
marks were then tied into the project datum allowing for seamless integration and use of the
water level monitoring data in the 2D hydraulic modeling.
4.1.4.1 Quality Assurance / Quality Control of Water Surface Elevation Data
Data from the loggers and surveys were compiled in a calculation spreadsheet for each site
which included pressure level, water temperature, compensated depth, barometric pressure, air
temperature, measured WSE, calculations of WSE at each time interval, data entry notes, review
charts, and QA/QC notes.
The relevant surveying information includes the local benchmark and WSE surveys collected
during installation, the mid-season download in August 2023 and transducer removal
(anticipated in September 2023), as well as the land surveyor control points collected by Edge.
The surveyor control points were collected in the project datum and allowed conversion of the
benchmarks and WSE collected in the local datum for each site into the project datum.
Pressure transducer data were recorded in feet of water and barometric pressure data were
recorded in kilopascals. Each was converted to inches of water and the compensated depth was
calculated. This depth was related to the WSE measured during the site visit and each subsequent
compensated depth value was used to estimate the WSE on a future timestep. Theoretically, the
calculated WSE should match the measured WSE during the next field effort; however, the
calculated and measured WSEs did not always match due to error (between the compensated
depth and measured WSE) or drift in the loggers. This error or drift was accounted for in the
calculations by incrementally applying it at each timestep between field visits such that the
calculated WSEs for the next field effort match those that were measured. The error, or logger
drift, was calculated as the difference between initial and final measurements of both
compensated depth and measured WSE.
Data analysis revealed that one pressure transducer at the lower left bank of the Falls at Site 110
was not functioning properly and did not record data. This transducer was replaced with a
different unit during the August 2023 field effort so will only have a portion of the record
available for calibration purposes.
Calculated WSEs and temperature values were reviewed in each spreadsheet to determine if the
units were out of water for any period of time or if they appeared to move during the time
deployed. QA/QC review information, recommendations, and changes were recorded in a tab in
each spreadsheet for documentation purposes. Once the final download and removal of units is
complete in September 2023, a final WSE record will be prepared for each site and used in
modeling calibration.
4.1.4.2 Planned Integration of Field Water Surface Elevation Data
The WSEs from each water level logger will be used in combination with the measured flows to
calibrate the 2D HEC-RAS Model. Additional information on calibration and validation will be
provided once the water level logger data is made available.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 12 December 2023
4.1.5 Stage-Discharge Curve
A stage-discharge curve was developed based on flow and WSE data collected at the Project site
during field surveys. This information is covered in greater detail in the Flow Duration Curve
Change Analysis Study Report (Attachment I)
4.1.6 Two-Dimensional Model Calibration
A 2D model using baseline flow conditions has been built and will be calibrated to measure
WSE data in various areas of the proposed model area. Model runs will be completed at various
flows to match the gaged WSEs at the specific locations. Manning’s n roughness values,
turbulence parameters, and 2D mesh parameters will be adjusted as needed to achieve defensible
calibration of the model. The calibrated model can then be used to finalize the 2D hydraulic
model, and the results may then be used for agent-based fish movement modeling as well as
other applications. Model calibration will be completed using calibration data expected at the end
of the 2023 field season.
4.2 Agent-Based Model Development
As noted above, the construction and operation of a hydroelectric project at Nuyakuk Falls has
the potential to impact anadromous fish populations by altering flows and related fish passage
conditions. However, without constructing a hydroelectric project and then observing changes in
fish passage efficiency, it is difficult to determine the direction or extent of potential impacts. To
assist in this evaluation, an ABM is being developed that incorporates known information on the
swimming ability, migratory behaviors, and perceptive abilities of fish species of interest to
provide objective insights into probable outcomes.
In an ABM, a collection of autonomous goal-directed software objects (agents) make decisions
to maximize their own well-being, interact with other agents, and react to a simulated
environment to produce emergent behaviors. Every agent in the model is an individual fish. Each
fish-agent’s emergent behaviors arise from simple rules that govern how it can react when
constrained by environmental conditions and interactions with other agents.
ABMs for fish passage have been used since 2006 to forecast movement patterns of fish in
response to flow (Goodwin et al. 2006) and navigating passage (Weber et al. 2006; Gilmanov et
al. 2019; Kopecki et al. 2022). Unlike earlier applications, this ABM emphasizes individual
interactions and schooling behavior to model density-dependent effects.
The Nuyakuk ABM will predict fish movement in 2D space and incorporates models and
parameter values from the literature. Year 1 studies have focused on the development of a proof-
of-concept ABM for Sockeye Salmon (Oncorhynchus nerka) and to design simulation
experiments for calibration and validation purposes.
4.2.1 Agent-Based Model Development Methods
The ABM simulates individual fish-agent movement over a 24-hour period within a 2 km stretch
of the Nushagak River at Nuyakuk Falls. Each fish agent is goal directed. At the start of the
simulation and every time step thereafter, the agent perceives their environment, reacts to
stimuli, and optimizes movement until they reach their goal or the simulation ends. Variables
include spatial location and internal energy states that are tracked every timestep. Each timestep
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 13 December 2023
is 1 second. Fish-agent behavior outputs from the model include estimated fish passage
efficiencies, passage rates, passage routes, and energy consumption as a function of flow.
4.2.1.1 Design Concepts
The fish agents in the Nuyakuk ABM react to the physical environment and the actions of other
fish agents. They are trying to optimize the distance traveled while maintaining enough energy
resources and avoiding collision with obstacles and other fish agents. The objective of each fish-
agent is simple, to cross the finish line, which is an arbitrary point in space that indicates a fish
has successfully passed Nuyakuk Falls. To avoid dead-ends and impassable sections, agents are
capable of remembering where they have been and avoiding these locations. Fish agents also
interact with other agents in schools, which makes it possible to understand density-dependent
effects on fish passage performance and/or identify the ability to collectively navigate as a school
over the Falls. The only stochastic processes in the model generate morphometric parameters and
starting locations at initialization. Everything else, including all emergent behavior, is
deterministic; therefore, the ABM represents a complex adaptive system. At every timestep, it
will be possible to observe what the agent perceives, their internal energy state and migratory
mode, heading arbitration, and the results of movement via jumping or swimming. With these
data, it will be possible to evaluate fish passage study objectives as well as to provide reasoning
for certain emergent behaviors. When the simulations run at different flows are compared, it will
be possible to predict how Sockeye Salmon may respond to a change in flow regime and hence
its passage success.
4.2.1.2 Details
When the model initializes, stochastic processes simulate morphometric parameters and starting
locations. All fish agents start in a school downstream of Nuyakuk Falls. The input data into the
ABM is the output from a depth-averaged, 0.5-meter resolution 2D hydraulic model. The fish
agents are modeled as a point in 2D space. Modeled motion and forces acting on agents are
surge, yaw, thrust, and drag. Submodules have been built into the ABM that sample
environmental parameters (X, Y, Z) as well as those that assess fatigue, heading arbitration,
movement, and energy consumption.
Sensing the Environment
For a real fish, navigation in space and time requires an individual fish to sense and respond to
the environment and the behavior of conspecifics as delimited by their sensory abilities (Cooke
et al. 2022). Therefore, at the start of every timestep, our fish agent senses its simulated
environment in much the same way a real fish senses its environment. The lateral line system of
a fish is capable of sensing changes in water velocity up to two body lengths away (Bleckmann
and Zelick 2009). Our fish agents simulate the lateral line by sampling from 2D flow velocity
surfaces (N and E) at that same buffer. Fish agents are also able to ‘see’ up to two body lengths
away and will identify the locations of other fish agents and obstacles/shallow areas at that same
two fish length buffer. Fish agents have ‘place’ responses and form a map-like memory of their
environment (Rodr guez et al. 2021) that is anchored and allows them to remember where they
have been, sampling from their own memory.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 14 December 2023
Assessing Fatigue and Recovery
Fish agents are allowed to fatigue, at which point they maintain a nominal tail beat and will fall
back if they cannot generate enough thrust to overcome drag. Castro-Santos (2005) provides time
to fatigue as a function of swimming speed and fish length. Time to fatigue is converted to a
battery state with the following logic; when fish start swimming anaerobically, their energy
reserves start to decrease. At the end of the first anaerobic timestep, energy reserves are reduced
proportionally to the length of the timestep compared to the time until fatigue.
When a fish reduces its swim speed below anaerobic levels, it starts to recover. Research on this
topic found that fish can perform at high levels within 45 minutes after depleting energy
reserves; thus this was an assumption for the ABM. The fish agent recovery process is the
fatigue process in reverse, except time-to-recovery is a function of the current battery state.
Heading Arbitration
The most important submodule is heading arbitration. Each fish agent is continuously receiving
information from its surroundings, including the speed and direction of other agents, the
locations of obstacles, and the water velocity in two directions. Fish agents are also responding
to their internal energy state. If they are nearing fatigue, they will respond to behavioral cues
differently than if they are fully recovered.
When fish are fatigued, they exhibit station-holding behavior. The fish only responds to
rheotactic cues and generates just enough thrust to match drag to maintain its position within the
water column. If it cannot generate enough thrust, the fish falls back. When fish are nearing a
fatigued state, they are using their lateral line to respond to rheotactic cues and search for a low-
energy refugia to recover. When a fish is fully recovered and in migratory mode, it is responding
to multiple behavioral cues. During migratory mode, fish agents respond to rheotactic cues
(Arnold 1974), spatial memory (Rodr guez et al. 2021), schooling and collision avoidance
(Reynolds 1987), and optimal depths to reduce wave drag (Hughes 2004). To arbitrate among
these cues and choose the optimal path strategy when in migratory mode, a fish agent uses
prioritized acceleration allocation (Reynolds 1987), which is based on a strict priority ordering of
behavioral cues. A fish is either attracted or repelled by each cue with a potential field. To
generate a heading vector when more than one behavioral cue is considered, the fish agent
simply sums vectors. The priority order is as follows:
1. If collision avoidance potential is greater than 0, the fish agent will abide by the collision
avoidance vectors.
2. If spatial memory potential is greater than 0, the fish agent will sum spatial memory and
rheotactic cues.
3. If the fish is in a school, it will respond to schooling and rheotactic cues.
4. Otherwise, the fish combines potentials from rheotaxis, low velocity, and wave drag
optimization to form a final heading.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 15 December 2023
Swimming and Jumping
After sensing their environment, assessing their level of fatigue, and arbitrating amongst the
many behavioral cues, fish agents now must decide whether they will jump or swim over the
next timestep. If the ratio to ideal speed over ground to water velocity is less than 0.05, the agent
is traveling against the flow, it has been more than 60 seconds since its last jump, and there is
more than 40% remaining in the internal battery state, a fish agent jumps. Jumping occurs in one
timestep. The fish agent is assumed to be able to accelerate to its critical swim speed as it exits
the water column, and once it exits the water column, the fish follows a ballistic trajectory. A
jump is successful if the fish can maintain enough swim speed where they land to maintain
position within the water column. If the fish cannot maintain its position, it will fall back.
When a fish agent is swimming, it first calculates drag using the formula from (Mirzaei 2017)
which accounts for the velocity of the fish agent and water velocity. With the amount of drag (N)
calculated, the fish agent now generates enough thrust to maintain its preferred speed-over-
ground. To apply movement when swimming, the fish agent calculates surge, then solves for
acceleration by rearranging Newton's 1st law of motion. Surge is basically thrust–drag. If thrust
is equal to drag, the fish maintains its current velocity; if thrust is greater than drag, the fish
accelerates; and if thrust is less than drag, the fish slows down.
Energy Consumption
The last fish agent submodule calculates the number of kCal burned during a timestep and
maintains a running sum. The intent of this method is to keep a running counter of the amount of
kCal consumed by converting the amount of oxygen respired into calories with standard
metabolic equations. Brett (1964) provides active metabolic (anerobic respiration) rates or
oxygen consumption (O2/kg/hr) as a function of water temperature and swimming speed (body
lengths/second), while Brett and Glass (1973) provide standard metabolic rate (aerobic
respiration) as a function of water temperature and weight. We used the approach of Hughes
(2004) to calculate the total metabolic rate (anaerobic and aerobic). The fish agent computes
each submodule every timestep.
Validation
Ngo and See (2012) developed a thorough, transparent, and objective method of validating
ABMs. A completely validated model must pass 1) face validation, 2) a sensitivity analysis, 3)
calibration, and 4) output validation. Once a model is validated, it can be used to assess passage
response at differing instream flow values.
Face validation is an initial visual and tabular assessment method that assesses animations for
realism, whether fish are behaving as expected, and whether the model outputs fall within an
acceptable range of real values. We will design simulation experiments to ‘gut-check’ speed over
ground, jumping locations, holding locations, passage routes, schooling behavior, and kCal
consumption. Face validation will be completed by the team of field biologists who were on-site
and regional experts with experience researching the species of interest. If the face validation of
any of these behaviors fails, adjustments will be made to the software, and it will be tested again.
Following face validation, we will perform a sensitivity analysis for critical assumptions used in
the model including fatigue response, heading arbitration, and jumping criteria. The migratory
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 16 December 2023
mode of a fish depends on its internal energy state. If the fish is nearing fatigue, it will not
behave the same way that a well-rested fish will. It is possible to adjust the point of transition
between behaviors and then assess the output. A fish agent needs to choose an optimal heading
strategy that is a function of its internal energy state. To choose the best heading, a fish uses
prioritized acceleration allocation. We will conduct a sensitivity analysis by adjusting the
weights and prioritization of each cue. The final sensitivity analysis surrounds the jump criteria,
which will adjust the ratio of speed over ground to water velocity and internal energy threshold
states.
Calibration and validation will use telemetry data collected in the summer of 2023. A portion of
the dataset will be used to calibrate speed over ground, while the other portion of the dataset will
be used to validate the output of the model with statistical comparisons. Output validation is
critical; if our model is able to reproduce passage success, rates, and routes at the discharge(s) we
observed, then our belief in the model output at other instream flows increases.
5.0 RESULTS
5.1 Two-Dimensional Model Development Results
As the calibration data is not available at this time, the results for the 2D hydraulic model are in
progress. The analysis is still underway and results will be provided in the USR. Results will
include velocity, depth, and inundation maps for the selected hydrology, which will be
determined based on additional flow data collected in the field.
5.2 Agent-Based Model Development Results
The primary programming, unit testing, and functional testing is complete. The code has been
released as open source under the MIT license and can be found at
https://github.com/knebiolo/emergent. Validation will occur throughout the fall of 2023, with
production runs occurring over Q1 and Q2 of 2024. The software produces an .mpg movie file, a
set of HDF databases for each agent, an HDF file for positional tracking, and georeferenced
mental map images that depict where an agent was in time. Summary functions will determine
passage success and passage rates, identify routes of passage, and track energy consumption over
time.
6.0 DISCUSSION AND FINDINGS
No discussion of findings is available until model calibration is complete. This will occur in the
spring of 2024 and be included as a part of the USR in December of 2024.
7.0 STUDY VARIANCES AND MODIFICATIONS
7.1 Two-Dimensional Model Variances
No variances are noted at this time from the RSP.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 17 December 2023
7.2 Agent-Based Model Variances
No variances are noted at this time from the RSP.
8.0 STUDY STATUS AND SCHEDULE
8.1 Two-Dimensional (2D) HEC-RAS Model Development
This Fish Passage Study is ongoing. During Year 1 studies, field data required to develop and
calibrate the models were collected including remote sensing imagery (LiDAR and aerial
photos), WSE data within the Falls Reach, and stage-discharge data. While the data collection is
nearly complete, data post-processing, analysis, and incorporation into the various model
elements will be completed based on the following schedule:
Final LiDAR imagery delivered by NV5 remote sensing October 2023
Finalized dataset of WSE field data following September field effort October 2023
2D model update presentation to ARWG October 2023
Final delivery of future flow results from CK Blueshift November 2023
Data integration/intermediate model runs and calibration December 2023
Final model development and runs February 2024
Model update presentation to ARWG April 2024
Completion report in support of the USR December 2024
8.2 Agent Based Model Development
The ABM aspect of the Fish Passage Study is ongoing. Development of the model depends on
data being generated based on completion of other studies, specifically the radio telemetry
portion of the Fish Community Study (Attachment A) which will provide behavior patterns of
adult Sockeye Salmon passing the Falls. These data are essential to the validation and calibration
of the ABM. The schedule and next steps in the ABM process is as follows:
ABM model update to the ARWG October 2023
Incorporation of radio telemetry study results November 2023
Intermediate model runs December 2023
Final model development and runs March 2024
Model update presentation to ARWG May 2024
Completion report in support of the USR December 2024
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 18 December 2023
9.0 STUDY-SPECIFIC CONSULTATION
The study plan for the Fish Passage Study, including selection of the modeling approach for both
the 2D model and the ABM, was completed with substantial input from the ARWG over the
initial period of study development from 2020-2022, and final revisions to the Federal Energy
Regulatory Commission (FERC)-filed RSP.
Since the ARWG and Cooperative decided on a modeling approach for the RSP, subsequent
meetings have occurred as models are developed to discuss inputs and assumptions with the
ARWG including:
May 10, 2023
Ben Cary provided a presentation to the ARWG on the development of the 2D HEC-
RAS model including a discussion of the terrain elevation dataset including the
LiDAR, bathymetry, and hand survey points, and channel and floodplain
characteristics. This presentation also outlined the planned flow, depth/velocity, and
flow direction outputs from the model.
Kevin Nebiolo provided a presentation to the ARWG on the application and
development of an Agent-Based Approach to modeling fish behavior in the Falls
Reach. Model framework, inputs of data from other studies, and a discussion of fish
passage behavior considerations was discussed with the ARWG.
June 14, 2023
Kevin Nebiolo provided an update on the development of the ABM and framework
for incorporating fish passage data. Discussion with the ARWG followed.
Model results and two model-specific Technical Memoranda (TM, in progress) will be
distributed to the ARWG in draft form in the Spring of 2024. The ARWG will have the
opportunity to review and provide comments and input prior to finalization of the TM.
10.0 REFERENCES
Arnold, GP 1974. “Rheotropism in fishes.” Biological reviews (Wiley Online Library) 49: 515–
576.
Bleckmann, Horst and Randy Zelick. 2009. “Lateral line system of fish.” Integrative zoology
(Wiley Online Library) 4: 13–25.
Bovee, K.D. 1982. A guide to stream habitat analysis using the Instream Flow Incremental
Methodology. Instream Flow Information Paper No. 12. USFWS Report FWS/OBS-82-
26.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 19 December 2023
Bovee, K., B. Lamb, J. Bartholow, C. Stalnaker, J. Taylor, and J. Henriksen. 1998. Stream
habitat analysis using the Instream Flow Incremental Methodology. Fort Collin, CO. U.S.
Geological Survey, Biological Resources Division. Information and Technical Report
USGS/BRD-1998-0004. 131 pp.
Brett, J.R. 1964. “The Respiratory Metabolism and Swimming Performance of Young Sockeye
Salmon.”Fisheries Research Board of Canada.
Brett, J.R. and N.R. Glass. 1973. “Metabolic rates and critical swimming speeds of sockeye
salmon (Oncorhynchus nerka) in relation to size and temperature.”Journal of the
Fisheries Board of Canada (NRC Research Press Ottawa, Canada) 30: 379–387.
Castro-Santos, Theodore. 2005. "Optimal swim speeds for traversing velocity barriers: an
analysis of volitional high-speed swimming behavior of migratory fishes." Journal of
Experimental Biology 208: 421-432. doi:10.1242/jeb.01380.
Cooke, Steven J., Jordanna N. Bergman, William M. Twardek, Morgan L. Piczak, Grace A.
Casselberry, Keegan Lutek, Lotte S. Dahlmo, et al. 2022. “The movement ecology of
fishes.” Journal of Fish Biology (Wiley Online Library) 101: 756–779.
Gilmanov, Anvar, Daniel Zielinski, Vaughan Voller, and Peter Sorensen. 2019. “The effect of
modifying a CFD-AB approach on fish passage through a model hydraulic dam.” Water
(MDPI) 11: 1776.
Goodwin, R. Andrew, John M. Nestler, James J. Anderson, Larry J. Weber, and Daniel P.
Loucks. 2006. “Forecasting 3-D fish movement behavior using a Eulerian–Lagrangian–
agent method (ELAM).” Ecological Modelling (Elsevier) 192: 197–223.
Hughes, Nicholas F. 2004. “The wave-drag hypothesis: an explanation for size-based lateral
segregation during the upstream migration of salmonids.” Canadian Journal of Fisheries
and Aquatic Sciences (NRC Research Press Ottawa, Canada) 61: 103–109.
Kopecki, Ianina, Matthias Schneider, and Tobias Hägele. 2022. “Novel Developments for
Sustainable Hydropower.” Chap. Attraction Flow and Migration Habitat Assessment
Using an Agent-Based Model in Novel Developments for Sustainable Hydropower83–90.
Springer.
Mirzaei, Parham A. 2017. “Development of a fish leaping framework for low-head barriers.”
Journal of Hydro-environment Research 14: 34-43.
doi:https://doi.org/10.1016/j.jher.2016.07.001.
Ngo, The An, and LInda See. 2012. “Agent-Based Models of Geographical Systems.” Chap.
Calibration and Validation of Agent-Based Models of Land Cover Change, edited by
Alison J. Happenstall, Andrew T. Crooks, Linda M. See and Michael Batty, 181-198.
New York: Springer.
Nuyakuk River Hydroelectric Project Nuyakuk Falls Fish Passage Study
FERC No. 14873 Initial Study Report – Attachment B
Nushagak Cooperative, Inc. 20 December 2023
Quantum Spatial. 2020. Nuyakuk River, Alaska Topobathymetric LiDAR Technical Data
Report. July 17, 2020.
Reynolds, Craig W. 1987. “Flocks, herds and schools: A distributed behavioral model.”
Proceedings of the 14th annual conference on Computer graphics and interactive
techniques. 25–34.
Rodr guez, Fernando, Blanca Quintero, Lucas Amores, David Madrid, Carmen Salas-Peña, and
Cosme Salas. 2021. “Spatial cognition in teleost fish: strategies and mechanisms.”
Animals (MDPI) 11: 2271.
Weber, Larry J., R. Andrew Goodwin, Songheng Li, John M. Nestler, and James J. Anderson.
2006. “Application of an Eulerian–Lagrangian–Agent method (ELAM) to rank
alternative designs of a juvenile fish passage facility.” Journal of Hydroinformatics (IWA
Publishing) 8: 271–295.
APPENDIX -:
www.nv5.com/geospatial
NuyakukRiver,Alaska
2023TopobathymetricLidar Technical DataReport
Prepared For:Prepared By:
McMillen Corp
CoryWarnock
5771ApplegroveLn.
Ferndale, WA 98248
PH: 360-384-2662
NV5 Geospatial Corvallis
2014MerrillFieldDrive
Anchorage, AK 99501
PH: 907-272-4495
October 16, 2023
Technical Data Report –Nuyakuk River Lidar Project
INTRODUCTION .................................................................................................................................................. 1
DeliverableProducts.................................................................................................................................. 2
ACQUISITION ..................................................................................................................................................... 4
Planning..................................................................................................................................................... 4
AirborneLidarSurvey................................................................................................................................ 5
DigitalImagery.....................................................................................................................................10
PROCESSING ...................................................................................................................................................11
TopobathymetricandUASNIRLidar Data...............................................................................................11
Bathymetric Refraction............................................................................................................................15
LidarDerivedProducts.............................................................................................................................15
Topobathymetric DEMs........................................................................................................................15
IntensityImages...................................................................................................................................15
DigitalImagery.........................................................................................................................................17
RESULTS &DISCUSSION ....................................................................................................................................18
Bathymetric Lidar.....................................................................................................................................18
MappedBathymetryandDepthPenetration.......................................................................................18
Lidar PointDensity...................................................................................................................................20
Snow-On Acquisition Density...............................................................................................................20
Snow-Off Acquisition Density...............................................................................................................23
Lidar AccuracyAssessments ....................................................................................................................26
LidarNon-VegetatedVerticalAccuracy................................................................................................26
Lidar RelativeVertical Accuracy...........................................................................................................26
LidarHorizontalAccuracy.....................................................................................................................28
DigitalImageryAccuracyAssessment......................................................................................................28
CERTIFICATIONS ...............................................................................................................................................29
GLOSSARY ......................................................................................................................................................30
APPENDIX A-ACCURACY CONTROLS ...................................................................................................................31
Cover Photo:A view over the falls on the Nuyakuk River.
TABLE OF CONTENTS
Technical Data Report –Nuyakuk River Lidar Project
Figure 1: LocationmapoftheNuyakukRiversite in Alaska.......................................................................... 3
Figure2:Snow-Ontopobathymetriclidaracquisitionflightlinesmap .......................................................... 7
Figure3:Snow-OffUASNIRlidaracquisitonflightlinesmap......................................................................... 9
Figure 4: A comparison of Intensity Images from Green and NIR first returns from the Snow-On
acquisition in the Nuyakuk River area ........................................................................................................16
Figure 5: Depth model of the Nuyakuk River generated from data collected during the Snow-On
acquisition...................................................................................................................................................19
Figure 6: Frequencydistributionoffirst returndensitiesper100 x 100 m cell, Snow-Onacquisition........21
Figure 7:Frequencydistributionofgroundandbathymetricbottomclassifiedreturndensitiesper
100 m x 100 m cell, Snow-On acquisition....................................................................................................21
Figure 8: Firstreturnandgroundand bathymetricbottom densitymapfortheNuyakuk Riversite
(100 x 100 m cells) during theSnow-On acquisition ...................................................................................22
Figure 9: Frequencydistributionoffirst returndensitiesper100 x 100 m cell,Snow-Offacquisition........23
Figure 10: Frequency distribution of ground classified return densities per 100 m x 100 m cell, Snow-Off
acquisition...................................................................................................................................................24
Figure 11: First return and ground density map for the Nuyakuk River site (100 m x 100 m cells) during
theSnow-Offacquisition.............................................................................................................................25
Figure 12: Frequencyplotforrelativevertical accuracybetweenflightlines, Snow-Onacquisition..........27
Figure 13: Frequencyplot forrelativevertical accuracybetweenflightlines, Snow-Offacquisition..........27
LIST OF FIGURES
Technical Data Report –Nuyakuk River Lidar Project
Table1: Acquisitiondates,acreage, anddata typescollectedontheNuyakukRiver site............................. 1
Table2:Deliverableproductcoordinatereferencesysteminformation....................................................... 2
Table3:Lidar andimageryproductsdeliveredfortheNuyakukRiver site................................................... 2
Table4: Lidar specificationsandaerialsurveysettings,Snow-Onacquisition.............................................. 6
Table5: Lidar specificationsandaerialsurveysettings, Snow-offacquisition.............................................. 8
Table6:Cameramanufacturer’s specificationsfor a ZenmuseP1 ..............................................................10
Table7:Project-specificorthophotospecifications.....................................................................................10
Table8: ASPRSLASclassificationstandardsappliedto the NuyakukRiver dataset....................................12
Table9:Snow-Ontopobathymetriclidarprocessingworkflow ..................................................................13
Table10:Snow-OffUASNIRlidar processingworkflow..............................................................................14
Table11:Orthophotoprocessingworkflow................................................................................................17
Table12: AverageLidar pointdensities, Snow-OnAcquisition...................................................................20
Table13: AverageLidar pointdensities, Snow-OffAcquisition...................................................................23
Table14: Relative accuracyresults..............................................................................................................26
Table15: Horizontal Accuracy.....................................................................................................................28
LIST OF TABLES
Technical Data Report –Nuyakuk River Lidar Project Page 1
In January 2023, NV5 Geospatial (NV5) was contracted by McMillen to collect topobathymetric Light
Detection and Ranging (lidar) data and digital imagery in the spring of 2023 during snow-on conditions
and NIR data and imagery in the summer of 2023 during snow-off conditions for the Nuyakuk River site
in Alaska. For the snow-on acquisition, traditional near-infrared (NIR) lidar was fully integrated with
green wavelength return data (bathymetric) lidar in order to provide a seamless topobathymetric lidar
dataset. This is a comprehensive project report detailing both the snow-on tobobathymetric and snow-
off NIR lidar acquisitions ofNuyukuk Falls in the Nuyukuk River area of interest. Data were collected as a
part of McMillen’s natural resource study program preceding the licensing of the proposed Nuyakuk
Falls Hydroelectric Project (P-14873) near Dillingham, Alaska.
This report accompanying the delivered topobathymetric lidar data, NIR lidar data, and imagery
documents contract specifications, data acquisition procedures, processingmethods, and analysisof the
final dataset including lidar accuracy, depth penetration, and density. Acquisition dates and acreage are
shown in Table 1, a complete list of contracted deliverables provided to McMillen is shown in Table 3
with the coordinate reference system information for these deliverables shown in Table 2, and the
project extent is shown in Figure 1.
Table1:Acquisitiondates,acreage,anddatatypescollectedontheNuyakukRiver site
Project Site ContractedAcres Buffered Acres Acquisition Dates Data Type
Nuyakuk River, Alaska 172 348 4/18/2023 Topobathymetric Lidar
Nuyakuk River, Alaska 172 348 7/2/2023 NIR Lidar
Nuyakuk River, Alaska 172 348 7/2/2023 3 band (RGB) Digital Imagery
This orthophoto, taken during the
Snow-Off acquisiton shows a view of
the NuyakukRiverinthe projectsitein
Alaska.
INTRODUCTION
Technical Data Report –Nuyakuk River Lidar Project Page 2
DeliverableProducts
Table2:Deliverableproductcoordinatereferencesysteminformation
Projection Horizontal Datum Vertical Datum Units
UTM Zone 4 NAD83 (2011)NAVD88 (GEOID12B)Meters
Table3:Lidarandimageryproducts deliveredfortheNuyakukRiversite
Product Type File Type Product Details
Points LAS v.1.4 (*.las)All Classified Returns
Rasters
1.0 meter Cloud
OptimizedGeoTiffs
Void-Interpolated TopobathymetricBareEarthDigital
Elevation Model (DEM)
Void-ClippedTopobathymetricBareEarthDigital
Elevation Model (DEM)
NIR Bare Earth Digital Elevation Model (DEM)
Highest Hit Digital Surface Model (DSM)
Rasters 0.5meterGeoTIFFs
(*.tif)
Green Sensor Intensity Images
NIR Sensor Intensity Images
Vectors Shapefiles (*.shp)
Buffered Boundary
Lidar Tile Index
Photo Tile Index
Hydro-Breaklines
Ground Survey Points
Bathymetric Coverage Shape
Digital
Imagery 3 cm GeoTiffs Tiled Imagery Mosaics
Digital
Imagery
3 cm MrSID
Compression AOI Imagery Mosaic
Metadata ExtensibleMarkup
Language (*.xml)Metadata
Reports AdobeAcrobat
(*.pdf)
2023 Lidar Technical Data Report
Supplemental 2020 Lidar Technical Data Report
Technical Data Report –Nuyakuk River Lidar Project Page 3
Technical Data Report –Nuyakuk River Lidar Project Page 4
Planning
In preparation for data collection, NV5 reviewed the project area and developed a specialized flight plan
to ensure complete coverage of the Nuyakuk River Lidar study area at the target combined point density
2 for the Snow-2 for the Snow-Off acquisition.
Acquisition parameters including orientation relative to terrain, flightaltitude, pulse rate, scan angle,
and ground speed were adapted to optimize flight paths and flight times while meeting all contract
specifications. Figure 2 and Figure 3 shows these optimized flight paths and dates.
The topobathymetric lidar acquisition was performedduring snow-onconditions in order to obtaindata
during low flow conditions of the Nuyakuk River. The topographic surface for the Snow-On
topobathymetric acquisition is therefore expected to have differences of up to four feet on non-
bathymetric surfaces compared to snow-off data. Additionally, the presence of snow renders a ground
survey ineffective as a means of control, and so no ground survey was utilized. See Table 10 and the
Lidar Accuracy Assessments section of this document for more information on the calibration of the
data represented in this report.
Other considerations made during the planning stage of this project include factors such as satellite
constellation availability and weather windows. Any weather hazards or conditions affecting the flight
were continuously monitoreddue to their potential impact on the daily success ofairborne operations,
and logistical considerations including private property access and potential air space restrictions were
duly made.
NV5 Geospatial’s Unmanned Aerial
System (UAS)
ACQUISITION
Technical Data Report –Nuyakuk River Lidar Project Page 5
Airborne Lidar Survey
The Snow-On topobathymetric lidar survey was accomplished using a Chiroptera 4X (CH4X) green laser
system mounted in a Cessna Grand Caravan. The CH4X sensor allows for a depth penetration of
K*Dmax=2.7. The CH4x performs well in dynamic wave action and automatically corrects for water
refraction, making it useful in collecting shallow coastal and shoreline data. It detects obstructions with
oblique lidar, such as vegetation and anthropogenic features. This means it can provide additional
information from multiplepositions that more closelyresembles the actual features and allows formore
analyses than traditional imagery. This system provides seamless integration between the NIR and
Green channels as well as between the onshore and shoreline data.
The CH4X laser system was dually mounted with an additional Leica 40kHZ deep bathymetric channel
known as a Leica HawkEye 4X (HE4X). The advanced design of the HE4X enables a higher density point
cloud with better resolution and depth penetration (up to 50 meters in optimal conditions) than the
CH4X shallow green laser at the same wavelength (515 nm). However, it is not designed for shallower
areas, which are acquired with the CH4X shallow green sensor. The bathymetric sub-systems of the
HawkEye 4X use a palmer scanner to produce an elliptical scan pattern of laser points with a degree of
incidence ranging from +/-14° (front and back) to +/-20° (sides), providing a 40° field of view. This has
the benefit of providing multiple look angles on a single pass and helps to eliminate shadowing effects.
This can be of particular use for bathymetric features(e.g., sides of narrow water channels; featureson
theseafloorsuchassmallerobjectsandwrecks).Thebathymetriclaseris adiode-pumpedclass4 laser.
Both the CH4x and HE4x systems acquire full waveform data for every pulse.The recorded waveform
enables range measurements for all discernible targets for a given pulse. The typical number of returns
digitized from a single pulse range from 1 to 7 in the Nuyakuk River project dataset. It is not uncommon
for some types of surfaces (e.g., dense vegetation or water) to return fewer pulses to the lidar sensor
thanthe laseroriginally emitted. The discrepancy between first return and overall delivered density will
vary depending on terrain, land cover, and the prevalence of water bodies. All discernible laser returns
were processed for the output dataset. Table 4 summarizes the settings used to yield an average pulse
density of 6 pulses/m2 over the Nuyakuk River project area. Figure 2 shows the flightlines acquired
using these lidar specifications.
All areas were surveyed with an opposing flight line side-lap of overlap) in order to reduce
laser shadowing and increase surface laser painting. To accurately solve for laser point position
(geographic coordinates x, y and z), the positional coordinates of the airborne sensor and the
orientation of the aircraft to the horizon (attitude) were recorded continuously throughout the lidar
data collection mission. Position of the aircraft was measured twice per second (2 Hz) by an onboard
differential GPS unit, and aircraft attitude wasmeasured 200 timesper second (200 Hz) as pitch, roll and
yaw (heading) from an onboard inertial measurement unit (IMU). To allow for post-processing
correction and calibration, aircraft and sensor position and attitude data are indexed by GPS time.
Technical Data Report –Nuyakuk River Lidar Project Page 6
Table4:Lidarspecificationsandaerialsurveysettings,Snow-Onacquisition
Parameter NIR Sensor Shallow Green Sensor Deep Green Sensor
Acquisition Dates 4/18/2023 4/18/2023 4/18/2023
Aircraft Used Cessna Grand Caravan Cessna Grand Caravan Cessna Grand Caravan
Sensor Leica Chiroptera 4x Leica Chiroptera 4x Leica HawkEye 4x
LaserChannel NIR Green (shallow)Green (deep)
MaximumReturns 9 4 4
Resolution/Density Average 6 pulses/m2 Average 6 pulses/m2 Average 6 pulses/m2
Nominal Pulse Spacing 0.41 m 0.41 m 0.41 m
Survey Altitude (AGL)400 m 400 m 400 m
Survey speed 145 knots 145 knots 145 knots
Field of View
Mirror Scan Rate 4200 RPM 3500 RPM 1880 RPM
Target Pulse Rate 250 kHz 35 kHz 11 kHz
PulseLength 2.5 ns 2.5 ns 2.5 ns
Laser Pulse Footprint
Diameter 10 cm 160 cm 288 cm
Central Wavelength 1064 nm 515 nm 515 nm
Pulse Mode ContinuousMultipulse ContinuousMultipulse ContinuousMultipulse
Beam Divergence 0.25 mrad 4 mrad 7.2 mrad
Swath Width 291 m 291 m 291 m
Swath Overlap
Intensity 16-bit 16-bit 16-bit
Technical Data Report –Nuyakuk River Lidar Project Page 7
The Snow-Off NIR lidar survey was accomplished using a Riegl VUX-1LR with Novatel IMU system
mountedon a DJI M600 Pro. Table 5 summarizes the settings used to yield an average pulse density of
50 pulses/m2 over the Nuyakuk River project area. The VUX-1LR laser system can record unlimited
range measurements (returns) per pulse, however a maximum of 15 returns can be stored due to LAS
v1.4 file limitations. The typical number of returns digitized from a single pulse range from 1 to 6 for the
Nuyakuk River project area. It is not uncommon for some types of surfaces (e.g., dense vegetation or
water) to return fewer pulses to the lidar sensor than the laser originally emitted. The discrepancy
between first return and overall delivered density will vary depending on terrain, land cover, and the
prevalence of water bodies. All discernible laser returns were processed for the output dataset. Figure 3
shows the flightlines acquired using these lidar specifications.
Table5:Lidarspecifications andaerialsurveysettings,Snow-offacquisition
RieglVUX-1LR
Technical Data Report –Nuyakuk River Lidar Project Page 8
Parameter NIR Laser
AcquisitionDates 6/20/2023
AircraftUsed DJI M600 Pro UAS
Sensor Riegl
LaserChannel VUX-1LR
Maximum Returns 7
Resolution/Density Average 50 pulses/m2
NominalPulseSpacing 0.125 m
SurveyAltitude(AGL)122 m
Surveyspeed 10 m/s
Fieldof View
MirrorScanRate 67 LinesPer Second
TargetPulseRate 600 kHz
PulseLength 3 ns
LaserPulseFootprintDiameter 6 cm
CentralWavelength 1064 nm
PulseMode MultipleTimesAround(MTA)
BeamDivergence 0.5 mrad
SwathWidth 240 m
Swath Overlap
Intensity 16-bit
VerticalAccuracy RMSEZ (Non-Vegetated) 6 cm
Technical Data Report –Nuyakuk River Lidar Project Page 9
Technical Data Report –Nuyakuk River Lidar Project Page 10
Digital Imagery
Aerial imagery was acquired using a Zenmuse P1 digital camera mounted to a DJI Matrice 300 RTK UAS
(Table 6). The Zenmuse is a small format aerial mapping camera which collects imagery in three spectral
bands (Red, Green, Blue).
Table6:Cameramanufacturer’sspecifications for a ZenmuseP1
Parameter ZenmuseP1 Specification
FocalLength 24 mm
Spectral Bands Red, Green, Blue
Pixel Size 4.39 m
Image Size 8,192 x 5,460 pixels
Frame Rate GPS triggered
FOV 74° x 53°
Date Format 8bit TIFF
For the Nuyakuk River site, 5,083 images were collected in three spectral bands (red, green, blue) with
designed to yield a native pixel resolutionof 0.05 m, however the native resolution supported0.03 m
orthophoto products. Orthophoto specifications particular to the Nuyakuk River project are in Table 7.
Table7:Project-specificorthophotospecifications
Parameter DigitalOrthophotography
Specification
GroundSampling Distance(GSD)0.2 ft pixel size
Along Track Overlap
Cross Track Overlap
Height Above Ground Level (AGL)160 meters
GPS PDOP
GPS Satellite Constellation
Technical Data Report –Nuyakuk River Lidar Project Page 11
Topobathymetric and UAS NIR Lidar Data
Upon completion of data acquisition, NV5 processing staff initiated a suite of automated and manual
techniques to process the data into the requested deliverables. Processing tasks included GPS control
computations, smoothedbestestimatetrajectory(SBET)calculations, kinematiccorrections, calculation
of laser point position, sensor and data calibration for optimal relative and absolute accuracy, and lidar
point classification (Table 8, Table 9, Table 10).
For the Snow-On topobathymetric lidar acquisition, Leica’s LSS software was used to facilitate
bathymetric return processing. Once bathymetric points were differentiated, they were spatially
corrected for refraction through the water column based on the angle of incidence of the laser. The
resulting point cloud data was classified using both manual and automated techniques. Processing
methodologieswere tailored for the landscape. Briefdescriptionsof these tasksare shown inTable 9.
This 2 meter lidar cross section showsa
view of the Nuyakuk River landscape,
colored by point classification.
PROCESSING
Technical Data Report –Nuyakuk River Lidar Project Page 12
Table8:ASPRSLASclassificationstandards appliedtotheNuyakukRiver dataset
Classification
Number ClassificationName ClassificationDescription Acquisition
1 Default/Unclassified
Laser returns that are not
included inthegroundclass,
composedofvegetationand
anthropogenic features
Snow-On
Snow-Off
2 Ground
Laser returns that are
determined to be ground using
automatedandmanualcleaning
algorithms
Snow-On
Snow-Off
40 Bathymetric Bottom
Refracted green laser returns
that fall within the water’s edge
breakline which characterize the
submerged topography.
Snow-On
41 Water Surface
Green laser returns that are
determinedtobewatersurface
points using automated and
manual cleaning algorithms.
Snow-On
42 SynthenticWater
Surface
Syntheticallygeneratedwater
surface Snow-On
45 Water Column
Refracted Riegl sensor returns
thataredeterminedtobewater
using automated and manual
cleaning algorithms.
Snow-On
Technical Data Report –Nuyakuk River Lidar Project Page 13
Table9:Snow-Ontopobathymetriclidarprocessingworkflow
Lidar Processing Step SoftwareUsed
Resolve kinematic corrections for aircraft position data using kinematic
aircraft GPS and staticground GPS data.Develop a smoothed best estimate
of trajectory (SBET) file that blends post-processed aircraft position with
sensor head position and attitude recorded throughout the survey.
Inertial Explorer v.8.9
MoveOutv.1.4(NV5Geospatial
Proprietary)
Calculate laser point position by associating SBETposition to each laser point
return time, scan angle, intensity, etc. Create raw laser point cloud data for
the entire survey in *.las (ASPRS v. 1.4) format. Convert data to orthometric
elevations by applying a geoid correction. Apply an initial calibration based
off recommended sensor settings from the manufacturer.
Lidar Survey Studio v.3.2.0
Las Projector 1.3 (NV5 Geospatial
proprietary)
Condition las files with channel, returnnumber and userbyte information.
Apply edge clip to data wider than 45 degrees from nadir to ensure most
accurate lidar data is being utilized.
LasMonkey2.6.7(NV5Geospatial
proprietary)
Classify ground points for individual flight lines
LasToolsLasGroundv.190507
TerraScan v.19.005
Using ground classified pointsper each flight line, test the relative accuracy.
Perform automated line-to-line calibrations for system attitude parameters
(pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate
calibrations on ground classified points from paired flight lines and apply
results to all points in a flight line. Use every flight line for relative accuracy
calibration. Use the 2020 VQ-880-GII grounded data as a calibration
reference for aligning with the previous dataset on hard surfaces.
StripAlign v.2.2.1
Import raw laser points into manageable blocks (less than 500 MB) to filter
erroneous points.TerraScanv.19.005
Apply refraction correction to all subsurfacereturns.Lidar Survey Studio v.3.2.0
Classify resultingdata to ground and other client designated ASPRS
classifications (Table 8).TerraScan v.19.005
TerraModelerv.19.003
Generatebare earth models as triangulated surfaces.Generate highest hit
models as a surface expression of all classified points. Export all surface
models as GeoTIFF (.tif) format at a 1 meter pixel resolution.
TerraScan v.19.005
TerraModelerv.19.003
LasProductCreator4.0(NV5
proprietary software)
Correct intensity values for variability and export intensityimages as cloud
optimized GeoTIFFs at a 0.5 meter pixel resolution.
LasMonkeyv.2.6.7(NV5
Geospatial proprietary)
TerraScan v.19.005
TerraModelerv.19.003
Technical Data Report –Nuyakuk River Lidar Project Page 14
Table10:Snow-OffUASNIRlidarprocessingworkflow
Lidar Processing Step SoftwareUsed
Resolve kinematic corrections for aircraft position data using kinematic
aircraft GPS and staticground GPS data.Develop a smoothed best estimate
of trajectory (SBET) file that blends post-processed aircraft position with
sensor head position and attitude recorded throughout the survey.
MoveOutv.1.4(NV5Geospatial
Proprietary)
Calculate laser point position by associating SBETposition to each laser point
return time, scan angle, intensity, etc. Create raw laser point cloud data for
the entire survey in *.las (ASPRS v. 1.4) format. Convert data to orthometric
elevations by applying a geoid correction. Apply an initial calibration based
off recommended sensor settings from the manufacturer.
Riegl RiProcess 1.9.3.5
Riegl RiUnite 1.0.5
Riegl RiPrecision 1.4.2
Condition las files with channel, returnnumber and userbyte information.
Apply edge clip to data wider than 45 degrees from nadir to ensure most
accurate lidar data is being utilized.
LasMonkey1.2.6.8(NV5
Geospatial proprietary)
Classify ground points for individual flight lines LasToolsLasGroundv.190507
Using ground classified pointsper each flight line, test the relative accuracy.
Perform automated line-to-line calibrations for system attitude parameters
(pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate
calibrations on ground classified points from paired flight lines and apply
results to all points in a flight line. Use every flight line for relative accuracy
calibration. Use the 2020 VQ-880-GII grounded data as a calibration
reference for aligning with the previous dataset on hard surfaces.
StripAlign v.2.2.1
Import raw laser points into manageable blocks (less than 500 MB) to filter
erroneous points.TerraScanv.19.005
Classify resultingdata to ground and other client designated ASPRS
classifications (Table 8).TerraScan v.19.005
TerraModelerv.19.003
Generatebare earth models as triangulated surfaces.Generate highest hit
models as a surface expression of all classified points. Export all surface
models as GeoTIFF (.tif) format at a 1 meter pixel resolution.
TerraScan v.19.005
TerraModelerv.19.003
LasProductCreator4.0(NV5
proprietary software)
Correct intensity values for variability and export intensityimages as cloud
optimized GeoTIFFs at a 0.5 meter pixel resolution.
LasMonkeyv.2.6.7(NV5
Geospatial proprietary)
TerraScan v.19
TerraModelerv.19
Technical Data Report –Nuyakuk River Lidar Project Page 15
BathymetricRefraction
Following final SBET creation for the Leica Chiroptera 4X, NV5 Geospatial used Leica Lidar Survey Studio
(LSS) to calculate laser point positioning by associating SBET positions to each laser point return time,
scan angle, and intensity. Leica LSS was used to derive a synthetic water surface to create a water
surface model. Light travels at different speeds in air versus water and its direction of travel or agle is
changed or refractedwhenenteringthe water column. The refraction tool corrects for this difference by
lidar data. LSS then outputs the Lidar point cloud as claswsified LAS 1.4 files.
Lidar Derived Products
Because hydrographic laser scanners penetrate the water surface to map submerged topography, this
affects how the data should be processed and presented in derived products from the lidar point cloud.
The following section discusses certain derived products that vary from the traditional (NIR)
specification and delivery format.
TopobathymetricDEMs
Bathymetric bottom returns can be limited by depth, water clarity, and bottom surface reflectivity.
Water clarity and turbidity affects the depth penetration capability of the green wavelength laser with
returninglaserenergydiminishing by scatteringthroughout the watercolumn. Additionally, the bottom
surface must be reflective enough to return remaining laser energy back to the sensor at a detectable
level. Although the predicted depth penetration range of the Chiroptera CH4X sensor is 1.5x Secchi
depths and the HE4x is 3x Secchi depths on brightly reflective surfaces, it is not unexpected to have no
bathymetric bottom returns in turbid or non-reflective areas. Since the HE4X is designed specifically for
deeper waters, it is expected to have fewer returns in shallower waters.
As a result, creating digital elevation models (DEMs) presents a challenge with respect to interpolation
of areas with no returns. Traditional DEMs are “unclipped”, meaning areas lacking ground returns are
interpolated from neighboring ground returns (or breaklines in the case of hydro-flattening), with the
assumption that the interpolation is close to reality. In bathymetric modeling, these assumptions are
prone to error because a lack of bathymetric returns can indicate a change in elevation that the laser
can no longer map due to increased depths. The resulting void areasmay suggest greater depths, rather
than similar elevations from neighboring bathymetric bottom returns. Therefore, NV5 created a water
polygon with bathymetric coverage to delineate areas with successfully mapped bathymetry. This
shapefile was used to control the extent of the delivered clipped topobathymetric model to avoid false
triangulation (interpolationfrom TIN’ing) acrossareas in the water without bathymetric bottom returns.
Intensity Images
The first returns of all valid point classes were used for both the green and NIR sensors in order to create
intensity images. With bathymetric lidar a more detailed and informative intensity image can be created
by using all or selected point classes, rather than relying on return number alone. If intensity
information of the bathymetry is the primary goal, water surface and water column points can be
excluded. However, water surface and water column points often contain potentially useful information
about turbidity and submerged but unclassified features such as vegetation. For the Nuyakuk River
project, NV5 created one set of intensity images from NIR laser first returns, as well as one set of
intensity images from green laser returns (Figure 4).
Technical Data Report –Nuyakuk River Lidar Project Page 16
Figure4: A comparison of Intensity Images from Green and NIR first returns from the Snow-On
acquisition in the Nuyakuk River area
Technical Data Report –Nuyakuk River Lidar Project Page 17
Digital Imagery
As with the lidar, the collected digital photographs went through multiple processing steps to create
final orthophoto products. Initially, imagery raw data was reviewed for completeness and compliance
with acquisition specifications.Within Agisoft’sMetashape software GPS data was applied to raw image
frames using the client specified coordinate reference system. Imagery was then aligned using
automatically generated tie points and camera calibration parameters. Using the 3D point cloud
generated during imagery alignment a mesh surface was derived to support image orthorectification.
Orthophotosweremosaicked usingautomatically generated seams and global color balancing ofthe
photo block.The processing workflow for orthophotos is summarized in Table 11.
Table11:Orthophotoprocessingworkflow
Orthophoto ProcessingStep SoftwareUsed
Reviewrawimagery data for AOI coverage and acquisition
specifications ArcMap v10.8
Apply GPS information to photos, and perform aerial
triangulation usingautomaticallygeneratedtiepointsand
ground control data.
Metashape v2.0
Generate 3D mesh surface for orthorectification Metashape v2.0
Mosaic orthorectified imagery blending automated seams
between photos and applying global color balancing to the
photo block.
Metashape v2.0
Technical Data Report –Nuyakuk River Lidar Project Page 18
Bathymetric Lidar
An underlying principle for collecting hydrographic lidar data is to survey near-shore areas that can be
difficult to collect with other methods, such as multi-beam sonar, particularly over large areas. The
capability and effectiveness ofthe bathymetric lidar isimpacted by several parameters includingdepth
penetrations below the water surface, bathymetric return density, and spatial accuracy.
Mapped Bathymetry and Depth Penetration
Under optimal conditions, the specified depth penetration range of the CH4x is about 1.5x Secchi depths
and the HE4x is 3x Secchi depths. Since the HE4X is designed specifically for deeper waters, there were
fewer returns from this sensor in shallower areas, which were acquired using the CH4X shallow green
sensor.To assist in evaluating performance results of the sensor, a polygon layer was created to
delineate areas where bathymetry was successfully mapped.
This shapefile was used to control the extent of the delivered clipped topo-bathymetricmodel and to
avoid false triangulation across areas in the water with no returns. Insufficiently mapped areas were
identified by triangulating bathymetric bottom points with an edge length maximum of 4.56 meters.
This ensured all areas of no returns (> 9 m2), were identified as data voids. Overall NV5 Geospatial
–
0.41 -1.15 m,had a calculateddepthof1.15 – 2.25 m,had a calculated depthof
This 2 meter lidar cross section shows a
viewofvegetation andbareground inthe
Nuyakuk River AOI, colored by point laser
echo.
RESULTS &DISCUSSION
Technical Data Report –Nuyakuk River Lidar Project Page 19
2.25 – 3.60 m,had a calculated depth of 3.60 – 4.71 m, and the remaining had acalculated
depth of 4.71 – 7.6 m (Figure 5). The maximum recorded depth for the Nuyakuk River topobathymetric
dataset was 7.57 m.
Figure5: Depth model of the Nuyakuk River generated from data collected during the Snow-On
acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 20
Lidar Point Density
The acquisition parameters were designed to acquire an average first-return density of 6 points/m
2. First
return density describes the density of pulsesemitted from the laser that return at least one echo to the
system. Multiple returns from a single pulse were not considered in first return density analysis. Some
types of surfaces (e.g., breaks in terrain, water and steep slopes) may have returned fewer pulses than
originally emitted by the laser.
First returns typically reflect off the highest feature on the landscape within the footprint of the pulse. In
forested or urban areas the highest feature could be a tree, building or power line, while in areas of
unobstructed ground, the first return will be the only echo and represents the bare earth surface.
The density of bathymetric bottom returns (Snow-On acquisition) and ground classified lidar returns
(Snow-On and Snow-Off acquisitions) were also analyzed for this project.Terraincharacter, landcover,
and ground surface reflectivity all influenced the density of ground surface returns. In vegetated areas,
fewer pulses may have penetrated the canopy, resulting in lower ground density.Similarly, the density
of bathymetric bottom returns was influenced by turbidity, depth, and bottom surface reflectivity. In
turbid areas, fewer pulses may have penetrated the water surface, resulting in lower bathymetric
density.
Snow-On Acquisition Density
The average first-return density of the Nuyakuk River Topobathymetric Lidar project Snow-On
acquisition was25.26 points/m
2 (Table 13). Thestatistical distributions of all first returndensities per
100 m x 100 m cell are portrayed in Figure 9.
The ground and bathymetric bottom classified density of lidar data for the Nuyakuk River project Snow-
On acquisition was 15.63 points/m2 (Table 13). Additionally, for the Nuyakuk River project Snow-On
Acquisition, density values of only bathymetric bottom returns were calculated for areas containing at
least one bathymetric bottom return. Areas lacking bathymetric returns (voids) were not considered in
calculatingan average density value. Within the successfully mapped area, a bathymetric bottom return
density of 5.19 points/m2 was achieved.
The statistical distributions per 100 m x 100 m cell of the ground and bathymetric bottom classified
return densities are portrayed in Figure 10.The spatial distributionof both first-return and ground and
bathymetric bottom classified densities is given in Figure 8.
Table12:AverageLidarpointdensities,Snow-OnAcquisition
Density Type Point Density
First Returns 25.26 points/m²
GroundandBathymetric
Bottom Classified Returns
15.63 points/m²
BathymetricBottom
ClassifiedReturns 5.19 points/m²
Technical Data Report –Nuyakuk River Lidar Project Page 21
Figure6:Frequency distributionoffirstreturndensities per100 x100 mcell, Snow-On acquisition
Figure7:Frequency distribution of groundand bathymetric bottomclassified return densities per
100 m x 100 m cell, Snow-On acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 22
Figure8: Firstreturn and ground and bathymetric bottom density map for the Nuyakuk River site
(100 x 100 m cells) during the Snow-On acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 23
Snow-Off Acquisition Density
The average first-returndensityofthe Nuyakuk RiverNIRLidarprojectfor Snow-Offacquisitionwas
118.36 points/m
2 (Table 13). The statistical distributionof all first return densitiesare portrayedin
Figure 9.
The groundclassifieddensityoflidar datafortheNuyakukRiverproject Snow-Offacquisitionwas
19.71 points/m
2 (Table 13).The statistical distributionof the ground classifiedreturn densities are
portrayed in Figure 10.
The spatial distribution of both first-return and groundandbathymetric bottom classified densitiesis
given in Figure 11.
Table13:AverageLidarpointdensities,Snow-OffAcquisition
Density Type Point Density
First Returns 118.36 points/m²
Ground Returns 19.71 points/m²
Figure9:Frequencydistributionoffirstreturndensities per100 x 100 m cell, Snow-Off acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 24
Figure10: Frequency distribution of ground classified return densities per 100 m x 100 m cell, Snow-
Off acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 25
Figure11: Firstreturn and ground density map for the Nuyakuk River site(100 m x 100 m cells) during
the Snow-Off acquisition
Technical Data Report –Nuyakuk River Lidar Project Page 26
Lidar Accuracy Assessments
The accuracy ofthe lidar data collection can be described in termsof absolute accuracy (the consistency
of the data with external data sources) and relative accuracy (the consistency of the dataset with itself).
See Appendix A for further information on sources of error and operational measures used to improve
relative accuracy.
Lidar Non-Vegetated Vertical Accuracy
Ground survey data was not available for an independent assessment of absolute vertical accuracy.This
dataset was calibrated to match an existing lidar dataset previously delivered in July 2020. Therefore,
this dataset was produced to meet a non-vegetated vertical accuracy (NVA) of 0.084 meters as
confidence interval1. For more information about the existing 2020 lidar survey, please review the
report titled Nuyakuk River, Alaska Topobathymetric Lidar Technical Data Report, dated July 17, 2020.
Lidar Relative Vertical Accuracy
Relative vertical accuracy refers to the internal consistency of the data set as a whole: the ability to
place an object in the same location given multiple flight lines, GPS conditions, and aircraft attitudes.
When the lidar system is well calibrated, the swath-to-swath vertical divergence is low (<0.10 meters).
The relative vertical accuracy was computed by comparing the ground surface model of each individual
flight line with its neighbors in overlapping regions.For the Snow-OnTopobathymetric Lidar acquisition,
the average (mean) line to line relative vertical accuracy for the Nuyakuk River Lidar project was
0.012 meters (Table 14, Figure 12). For the Snow-Off NIR Lidar acquisition, the average (mean) line to
line relative vertical accuracy for the Nuyakuk River Lidar project was 0.048 meters (Table 14, Figure 13).
Table14:Relativeaccuracyresults
Parameter Relative Accuracy
Snow-OnAcquisition
Relative Accuracy
Snow-OffAcquisition
Sample 22 surfaces 22 surfaces
Average 0.012 m 0.048 m
Median 0.013 m 0.050 m
RMSE 0.032 m 0.049 m
Standard Deviation 0.020 m 0.007 m
0.039 m 0.013 m
1 Federal Geographic Data Committee,ASPRS POSITIONAL ACCURACY STANDARDS FORDIGITAL GEOSPATIAL DATA
EDITION 1, Version 1.0, NOVEMBER 2014.
https://www.asprs.org/a/society/committees/standards/Positional_Accuracy_Standards.pdf.
Technical Data Report –Nuyakuk River Lidar Project Page 27
Figure12:Frequencyplotfor relativevertical accuracybetweenflightlines,Snow-Onacquisition
Figure13:Frequencyplotfor relativevertical accuracybetweenflightlines,Snow-Offacquisition
Technical Data Report –Nuyakuk River Lidar Project Page 28
Lidar Horizontal Accuracy
Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional
error, flying altitude, and inertial navigation system (INS) derived attitude error. The obtained RMSEr
value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National
Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within
the obtained radius 95 percent of the time. Based on a flying altitude of 400 meters, an IMU error of
0.001 decimal degrees, and a GNSS positional error of 0.005 meters, the Snow-On acquisition for this
project was produced tomeet 0.023 meters horizontal accuracy at the confidence level (Table15).
The information necessary to compute horizontal accuracy statistics was not available for the UAS
Snow-Off acquisition.
Table15:HorizontalAccuracy
Parameter
Horizontal Accuracy
Snow-On Acquisition
RMSEr 0.013 m
ACCr 0.023 m
Digital Imagery Accuracy Assessment
Ground control wasnotcollectedto support orthophoto processing or a spatial accuracy assessment.
Aerial triangulation was performed to refine GPS data from the airborne collection and the final
orthophoto products were tested for coregistration with the lidar dataset.
Technical Data Report –Nuyakuk River Lidar Project Page 29
Oct 25, 2023
NV5Geospatialprovidedlidar servicesforthe NuyakukRiverprojectasdescribedinthisreport.
I, Shauna Gutierrez, have reviewed the attached report for completeness and hereby state that it is a
complete and accurate report of this project.
Shauna Gutierrez Oct 25, 2023
Shauna Gutierrez (Oct 25, 2023 15:43 CDT)
Shauna Gutierrez
Project Manager
NV5 Geospatial
I, Evon P. Silvia, PLS, being duly registered as a Professional Land Surveyor in and by the state of Alaska,
hereby certify that the methodologies, static GNSS occupations used during airborne flights, and ground
survey point collection were performed to meet the project requirements and with the limitations
described in this report. Field work for the airborne survey for this report was conducted on April 18 and
June 20, 2023.
Accuracy statistics shown inthe Accuracy Sectionof this Report have been reviewed by me and found to
meet the “National Standard for Spatial Data Accuracy”.
Evon P. Silvia, PLS
NV5 Geospatial
Corvallis,OR97330
Oct 25, 2023
CERTIFICATIONS
Technical Data Report –Nuyakuk River Lidar Project Page 30
1-sigma Absolute Deviation: Value for which the data are within one standard deviation (approximately 68
th percentile) of
a normally distributed data set.
1.96 * RMSE Absolute Deviation: Value for which the data are within two standard deviations (approximately 95
th percentile)
of a normally distributed data set, based on the FGDC standards for Non-vegetated Vertical Accuracy (NVA) reporting.
Accuracy: The statistical comparison between known (surveyed) points and laser points. Typically measured as the standard
deviation (sigma ) and root mean square error (RMSE).
Absolute Accuracy:
divergence of lidar point coordinates from ground survey point coordinates. To provide a sense of the model predictive
power of the dataset, the root mean square error (RMSE) for vertical accuracy is also provided. These statistics assume
the error distributions for x, y and z are normally distributed, and thus we also consider the skew and kurtosis of
distributions when evaluating error statistics.
Relative Accuracy:Relative accuracy refers to the internal consistency of the data set; i.e., the ability to place a laser
point in the same location over multiple flight lines, GPS conditions and aircraft attitudes. Affected by system attitude
offsets, scale andGPS/IMU drift, internal consistency ismeasured as the divergence betweenpointsfrom different flight
lines within an overlapping area. Divergence is most apparent when flight lines are opposing. When the lidar system is
well calibrated, the line-to-line divergence is low (<10 cm).
Root Mean Square Error (RMSE): A statistic used to approximate the difference between real-world points and the lidar
points. It is calculated by squaring all the values, then taking the average of the squares and taking the square root of the
average.
Data Density: A common measure of lidar resolution, measured as points per square meter.
Digital Elevation Model (DEM): File or database made from surveyed points, containing elevation points over a contiguous
area. Digital terrain models (DTM) and digital surface models (DSM) are types of DEMs. DTMs consist solely of the bare earth
surface (ground points), while DSMs include information about all surfaces, including vegetation and man-made structures.
Intensity Values: The peak power ratio of the laser return to the emitted laser, calculated as a function of surface reflectivity.
Nadir: A single point or locus of points on the surface of the earth directly below a sensor as it progresses along its flight line.
Overlap: The area shared between flight lines, typically measured in percent.overlap is essential to ensure complete
coverage and reduce laser shadows.
Pulse Rate (PR): The rate at which laser pulses are emitted from the sensor; typically measured in thousands of pulses per
second (kHz).
Pulse Returns: For every laser pulse emitted, the number of wave forms (i.e., echoes) reflected back to the sensor. Portions of
the wave form that return first are the highest element in multi-tiered surfaces such as vegetation. Portions of the wave form
that return last are the lowest element in multi-tiered surfaces.
Real-Time Kinematic (RTK) Survey: A type of surveying conducted with a GPS base station deployed over a known monument
with a radio connection to a GPS rover. Both the base station and rover receive differential GPS data and the baseline
correction is solved between the two. This type of ground survey is accurate to 1.5 cm or less.
Post-Processed Kinematic (PPK) Survey: GPS surveying is conducted with a GPS rover collecting concurrently with a GPS base
station set up over a known monument. Differential corrections and precisions for the GNSS baselines are computed and
applied after the fact during processing. This type of ground survey is accurate to 1.5 cm or less.
Scan Angle: The angle from nadir to the edge of the scan, measured in degrees. Laser point accuracy typically decreases as
scan angles increase.
Native Lidar Density: The number of pulses emitted by the lidar system, commonly expressed as pulses per square meter.
GLOSSARY
Technical Data Report –Nuyakuk River Lidar Project Page 31
RelativeAccuracy Calibration Methodology:
Manual System Calibration: Calibration procedures for each mission require solving geometric relationships that relate
measuredswath-to-swathdeviations to misalignmentsof system attitude parameters. Corrected scale, pitch, roll and heading
offsets were calculated and applied to resolve misalignments. The raw divergence between lines was computed after the
manual calibration was completed and reported for each survey area.
Automated Attitude Calibration: All data was tested and calibrated using TerraMatch automated sampling routines. Ground
points were classified for each individual flight line and used for line-to-line testing. System misalignment offsets (pitch, roll and
heading) and scale were solved for each individual mission and applied to respective mission datasets. The data from each
mission were then blended when imported together to form the entire area of interest.
Automated Z Calibration: Ground points per line were used to calculate the vertical divergence between lines caused by vertical
GPS drift. Automated Z calibration was the final step employed for relative accuracy calibration.
Lidar accuracy error sources and solutions:
Source Type PostProcessing Solution
Long Base Lines GPS None
Poor Satellite Constellation GPS None
Poor Antenna Visibility GPS Reduce Visibility Mask
Poor System Calibration System Recalibrate IMU and sensor offsets/settings
Inaccurate System System None
Poor Laser Timing Laser Noise None
Poor Laser Reception Laser Noise None
Poor Laser Power Laser Noise None
Irregular Laser Shape Laser Noise None
Operational measures taken to improve relative accuracy:
Focus Laser Power at narrow beam footprint: A laser return must be received by the system above a power threshold to
accurately record a measurement. The strength of the laser return (i.e., intensity) is a function of laser emission power, laser
footprint, flight altitude and the reflectivity of the target. While surface reflectivity cannot be controlled, laser power can be
increased and low flight altitudes can be maintained.
Reduced Scan Angle: Edge-of-scan data can become inaccurate. The scan angle was reduced to a maximum of ±20o to ±21o
for the green and NIR lasers, respectively, from nadir, creating a narrow swath width and greatly reducing laser shadows from
trees and buildings.
Quality GPS: Flights took place during optimal GPS conditions (e.g., 6 or more satellites and PDOP [Position Dilution of
Precision] less than 3.0). Before each flight, the PDOP was determined for the survey day.
Ground Survey: Ground survey point accuracy (<1.5 cm RMSE) occurs during optimal PDOP ranges and targets a minimal
baseline distance of 4 miles between GPS rover and base. Robust statistics are, in part, a function of sample size (n) and
distribution. Ground survey points are distributed to the extent possible throughout multiple flight lines and across the survey
area.
-: Overlapping areas are optimized for relative accuracy testing. Laser shadowing is minimized to
-lap, the nadir portion of one flight line
coincides withthe swath edgeportionof overlapping flight lines. A minimum of side-lap with terrain-followed acquisition
prevents data gaps.
Opposing Flight Lines: All overlapping flight lines have opposing directions. Pitch, roll and heading errors are amplified by a
factor of two relative to the adjacent flight line(s), making misalignments easier to detect and resolve.
APPENDIX A-ACCURACY CONTROLS
Created:
By:
Status:
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EmilyHoard (emily.hoard@nv5.com)
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Nuyakuk_Combined_Aquisition_Lidar_Report_Fi
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INITIAL STUDY REPORT
ATTACHMENT C: FISH ENTRAINMENT AND IMPINGEMENT STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 3
5.0 RESULTS........................................................................................................................... 3
6.0 DISCUSSION AND FINDINGS........................................................................................ 4
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 4
8.0 STUDY STATUS AND SCHEDULE................................................................................ 4
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 4
LIST OF FIGURES
Figure 3-1. Fish entrainment and impingement study area..............................................................2
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. iii December 2023
ACRONYMS AND ABBREVIATIONS
2D two-dimensional
ADFG Alaska Department of Fish and Game
ARWG Aquatics Resources Working Group
Cooperative Nushagak Electric & Telephone Cooperative
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ISR Initial Study Report
NMFS National Marine Fisheries Service
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USR Updated Study Report
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
The intake for the proposed Nuyakuk River Hydroelectric Project (Project) has the potential to
impact fishes as they migrate, particularly juvenile fishes moving downstream past the Project. A
successful Project design will incorporate intake features that minimize potential impacts
associated with the entrainment, impingement, and mortality of fishes. The Nushagak Electric &
Telephone Cooperative (Cooperative), in collaboration with the Aquatic Resources Working
Group (ARWG), defined the methods and analytical tools to assess the potential for fish
entrainment and impingement at the proposed hydropower intake, and to provide clear design
thresholds to minimize harm to downstream migrating fish due to entrainment and/ or
impingement.
2.0 STUDY GOALS AND OBJECTIVES
The primary goal of this study is to understand the potential for the Project to entrain fishes that
are in the vicinity of the intake and to minimize the level of injury and mortality that might be
associated with entrainment or passage through the Falls Reach. Specific objectives follow.
1. Inform the preliminary intake design (e.g., infrastructure, orientation and trash rack
spacing) utilizing the hydraulic model developed under the Fish Passage Study and
through a compilation of information from similar projects that are subject to
analogous environmental conditions as well as potential guidance/deterrent structures.
2. Estimate flow fields and magnitude of approach velocities near the hydropower
intake over the range of operating flows to evaluate threshold conditions at the
proposed intake to minimize entrainment of juvenile salmonids and maximize
survival within the Project area; and measure behavior (including vertical and
horizontal distribution across the river) of downstream migrating juveniles in
proximity to the proposed intake site.
3. Utilize information collected under the Fish Abundance and Distribution Study to
identify fish species potentially impacted and their seasonal abundance and size
distribution--develop a list of target fish species.
4. Determine the swimming capacities and flow avoidance/attraction behavior of target
fish species from available literature.
5. Estimate potential for entrainment and impingement rates for target fish species based
on fish size, swimming ability and periodicity, local hydrology, Project technical
features (including trash rack design), and operating regime using available data from
entrainment studies involving the same species.
6. Estimate turbine mortality rates for target fish species and sizes by evaluating
mortality at other hydroelectric facilities with similar turbine specifications and
comparable physical features and operating conditions.
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. 2 December 2023
7. Estimate Project-related and overall mortality of target fish species on a seasonal and
annual basis using flow-based entrainment and mortality models.
Questions and hypotheses that will be addressed by this study are listed below.
1. What is the estimated potential for entrainment of juvenile salmonids through the
powerhouse?
2. What is the estimated potential for bypassing or entraining juvenile salmonids
through the Falls Reach?
3. What is the estimated direct and indirect mortality of juvenile salmonids that are
entrained into the powerhouse?
3.0 STUDY AREA
The geographic focus of the Fish Entrainment and Impingement Study will be the area extending
upstream of Nuyakuk Falls approximately 1,000 feet (Figure 3-1). In particular, the area near the
right bank of the river will be of interest due to its proximity to the proposed intake location. The
extent of the study area may be modified according to new information on hydraulics and flow
fields generated from 2D modeling.
Figure 3-1. Fish entrainment and impingement study area.
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. 3 December 2023
4.0 METHODOLOGY
When this study commences in Year 2, the Cooperative will follow the methods as presented in
the Revised Study Plan (RSP) including the following steps.
1. Conduct a literature review of hydroelectric projects with similar intake design, guidance
and/or deterrence systems to inform the risk of and ability to avoid injury and mortality
associated with impingement and entrainment through the powerhouse.
2. Use output from the 2D model to evaluate approach velocities at the intake and flowlines
resulting from potential groin alternatives.
3. Conduct an analysis of potential injury and mortality that may be associated with
entrainment or impingement at the Project or passage through the Falls under altered flow
conditions.
This study will also make use of Year 1 (2023) study results included in the Fish Passage Study
(Initial Study Report (ISR) Attachment B), the Fish Community Study (ISR Attachment A) with
site-specific data on the downstream migration distributions of juvenile salmon, and the overall
periodicity chart that is being developed. As this study relies on results from Year 1 field efforts,
no work has been initiated and there are no results to present at this time.
5.0 RESULTS
The Entrainment/ Impingement study is scheduled to begin in the spring of 2024 as Year 2
studies commence and following the final analysis of Year 1 studies that will contribute essential
input to the Entrainment/ Impingement analysis. These inputs include:
1. Fish Community Study:
Downstream migration timing, periodicity, and spatial distribution of downstream
migrating juvenile salmon in the vicinity of the proposed Project intake.
Periodicity data on the presence of both resident and migratory species at various life
stages that use habitat in the vicinity of the proposed Project intake.
2. Fish Passage Study:
Two-dimensional hydrologic flow model.
3. Flow Duration Curve Change Analysis Study
Stage-Discharge relationship that will work with results from the 2D model to
provide information on the range of flow conditions at the proposed Project intake.
Nuyakuk River Hydroelectric Project Fish Entrainment and Impingement Study
FERC No. 14873 Initial Study Report – Attachment C
Nushagak Cooperative, Inc. 4 December 2023
6.0 DISCUSSION AND FINDINGS
There will be further discussion of findings following the above-described methodologies to be
completed during Year 2 studies.
7.0 STUDY VARIANCES AND MODIFICATIONS
None identified at this time.
8.0 STUDY STATUS AND SCHEDULE
This study will be initiated in Year 2, 2024, and completed prior to the Year 2 Updated Study
Report (USR) in December of 2024.
9.0 STUDY-SPECIFIC CONSULTATION
The Federal Energy Regulatory Commission (FERC)-approved study plan was developed with
significant input from the ARWG, most notably the National Marine Fisheries Service (NMFS),
and the Alaska Department of Fish and Game (ADFG). As literature review and outreach to
project owners occur in 2024, the Cooperative’s team will continue to coordinate with the
ARWG during regularly scheduled meetings.
No consultations specific to this study have been completed in Year 1.
INITIAL STUDY REPORT
ATTACHMENT D: ASSESSMENT OF FALSE ATTRACTION TO THE TAILRACE
BARRIER
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
2.1 Study Goals and Objectives.................................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 2
5.0 RESULTS........................................................................................................................... 3
6.0 DISCUSSION AND FINDINGS........................................................................................ 3
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 3
8.0 STUDY STATUS AND SCHEDULE................................................................................ 3
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 4
LIST OF FIGURES
Figure 3-1. Assessment of False Attraction at the Tailrace Fish Barrier Study Area......................2
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. iii December 2023
ACRONYMS AND ABBREVIATIONS
2D two-dimensional
ADFG Alaska Department of Fish and Game
ARWG Aquatics Resources Working Group
Cooperative Nushagak Electric & Telephone Cooperative
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ISR Initial Study Report
NMFS National Marine Fisheries Service
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USGS U.S. Geological Survey
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
Hydropower project operations can result in false attraction to the proposed Nuyakuk River
Hydroelectric Project (Project) works, resulting in potential for migration delay. This study will
use information on passage timing at Nuyakuk Falls (Falls) as well as review of other tailrace
facilities to evaluate the potential for Project-related delay and will refine engineering design of
turbine outflow in the tailrace. As this study is dependent on results of Year 1 (2023) two-
dimensional (2D) model development and salmon telemetry data collection, it will be completed
during Year 2 of the study program (2024).
2.0 STUDY GOALS AND OBJECTIVES
2.1 Study Goals and Objectives
The overall goal of this study is to inform tailrace design and outflow options to minimize
potential impacts to upstream migrating fishes.
The primary objectives of this study are as follows:
1. Complete a review of tailrace designs that minimize false attraction by salmon to
determine any conceptual alternatives that would be suited to the Project and would
likely minimize false attraction.
2. Conduct a feasibility evaluation of the performance of tailrace location and design
concepts that might minimize false attraction under a variety of operating regimes.
3. Determine and provide preliminary level designs of any tailrace refinements to
minimize adult salmon injury and mortality associated with tailrace conditions, e.g.,
jumping at turbine draft tubes and the potential for blade strike.
4. In coordination with the fish community study, assess pre-Project across channel
distribution of upstream migrating salmon with respect to the proposed tailrace and
Falls tail outs.
5. In coordination with the fish passage study, evaluate potential changes post-Project in
staging and ascension habitat below the Falls proper for suitability and
connectiveness with respect to upstream migration routes and the potential for delay.
6. In coordination with the Life Cycle Model study, assess the potential risk that results
from incidental or latent mortality for fish that are falsely attracted to the tailrace.
Specific questions that will be addressed by this study follow.
1. Can the powerhouse discharge and tailrace design features minimize the potential to
attract fish to the tailrace at this location?
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. 2 December 2023
3.0 STUDY AREA
The geographic scope of the False Attraction Assessment will focus on the area surrounding the
proposed tailrace outfall below Nuyakuk Falls. The area of focus will extend from the three
distinct chutes or route options at the downstream end of the Nuyakuk Falls cascade that includes
the proposed tailrace outfall area, downstream approximately 1,500 ft along the right bank of the
river (looking downstream) (Figure 3-1). The extent of the study area may be modified according
to new information on hydraulics and flow fields generated from 2D modeling.
Figure 3-1. Assessment of False Attraction at the Tailrace Fish Barrier Study Area.
4.0 METHODOLOGY
The Nushagak Electric & Telephone Cooperative (Cooperative)will follow the methods as
described in the Revised Study Plan (RSP). Based on data from Year 1 studies these methods
may be refined and/or revised in collaboration with the Aquatics Resources Working Group
(ARWG) following the complete analysis and reporting on the Year 1 study. Study steps are
listed below.
1. Review available information on existing tailrace designs to minimize potential for false
attraction.
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. 3 December 2023
2. The Cooperative will conduct a brainstorming session with the ARWG. The session will
be focused on selecting 2 or 3 conceptual design alternatives. The 2D flow model will be
used to evaluate feasibility and compare alternatives.
3. If determined necessary after Step 2, conduct the preliminary design of tailrace exclusion
refinements.
5.0 RESULTS
The False Attraction Flow study is scheduled to begin in the spring of 2024 as Year 2 studies
commence and following the final analysis of Year 1 studies that will contribute essential input
to the False Attraction Flow analysis. These inputs include:
1. Fish Community Study:
Upstream migration timing, periodicity, and spatial distribution of upstream migrating adult
salmon in the vicinity of the proposed Project outflow, including staging and milling behavior of
adult salmon below the falls.
Periodicity data on the presence of both resident and migratory species at various life stages that
use habitat in the vicinity of the proposed Project outflow.
2. Fish Passage Study:
Two-dimensional hydrologic flow model
3. Flow Duration Curve Change Analysis Study
Stage-Discharge relationship that will work with results from the 2D model to provide
information on the range of flow conditions at the proposed Project outflow.
6.0 DISCUSSION AND FINDINGS
There will be further discussion of findings following the above-described methodologies to be
completed during Year 2 studies.
7.0 STUDY VARIANCES AND MODIFICATIONS
None identified at this time.
8.0 STUDY STATUS AND SCHEDULE
This study will be initiated in Year 2, 2024 and completed prior to the Year 2 Updated Study
Report (USR) in December of 2024.
Nuyakuk River Hydroelectric Project Tailrace False Attraction
FERC No. 14873 Initial Study Report – Attachment D
Nushagak Cooperative, Inc. 4 December 2023
9.0 STUDY-SPECIFIC CONSULTATION
The Federal Energy Regulatory Commission (FERC)-approved study plan was developed with
significant input from the ARWG, especially the National Marine Fisheries Service (NMFS) and
the Alaska Department of Fish and Game (ADFG). As literature review and outreach to project
owners take place in 2024, the Cooperative’s team will continue to coordinate with the ARWG
during regularly scheduled meetings.
No consultations specific to this study have been completed in Year 1.
INITIAL STUDY REPORT
ATTACHMENT E: SOCKEYE AND CHINOOK LIFE CYCLE MODELS
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
FERC No. 14873 Initial Study Report – Attachment E
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 4
4.1 Development of life cycle models .......................................................................... 4
4.1.1 Background of Sockeye life cycle model ................................................... 6
4.2 Data acquisition and analysis .................................................................................. 6
4.3 Linkage with a quantitative risk assessment from the LCM................................... 7
5.0 RESULTS ........................................................................................................................... 7
5.1.1 Sockeye life cycle model ............................................................................ 7
5.2 Data acquisition and analysis .................................................................................. 8
5.3 Development of a quantitative risk assessment .................................................... 11
6.0 DISCUSSION AND FINDINGS...................................................................................... 12
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 13
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 13
9.0 STUDY-SPECIFIC CONSULTATION ........................................................................... 14
10.0 REFERENCES ................................................................................................................. 14
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
FERC No. 14873 Initial Study Report – Attachment E
Nushagak Cooperative, Inc. ii December 2023
LIST OF FIGURES
Figure 3-1 Life cycle schematic for a baseline model including the life stages and their
location relative to the Nuyakuk falls......................................................................3
Figure 3-2. Life cycle schematic including life stage, their geographic location, and project
effects on those life stages.......................................................................................4
Figure 4-1. Sockeye life cycle model components and potential data available for
estimating transition equations. Shaded boxes indicate potential data that
can be collected from the Nuyakuk and other Sockeye populations in
tributaries to Bristol Bay, Alaska. Escapement can be estimated from tower
counts, harvest can be estimated from catch records, 1+ smolts and 2+
smolts can be estimated from juvenile surveys........................................................6
Figure 5-1. Sockeye straw life cycle model initial outputs include harvest (right) and age-4,
age-5, and age-6 escapement (left) over a 30-year time-period...............................8
Figure 5-2. Juvenile production of smolts in the Kvichak (top) and Afognak (bottom)
Sockeye populations. Points are the sum of age-1 and age-2 smolts
produced by the escapement in the appropriate brood year. ....................................9
Figure 5-3. Histogram of annual production of age-1 and age-2 smolts per adult in the
escapement in the Kvichak and Afognak populations. Small hash lines on
the x-axis indicate the observed production (smolt/escapement) in each
brood year. .............................................................................................................10
Figure 5-4. Test for Ricker type density dependence in the Kvichak (top) and Afognak
(bottom) Sockeye populations by plotting log(Smolts/Escapement) versus
Escapement. ...........................................................................................................11
Figure 6-1. Sockeye life cycle model components and potential data available for
estimating transition equations. Potential locations of density dependence
(DD) in the life cycle is shown as blue circles.......................................................13
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ACRONYMS AND ABBREVIATIONS
ARWG Aquatics Resources Working Group
Commission Federal Energy Regulatory Commission
Cooperative Nushagak Electric & Telephone Cooperative
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
IRA Integrated Risk Assessment
ISR Initial Study Report
LCM Life Cycle Model
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USR Updated Study Report
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
FERC No. 14873 Initial Study Report – Attachment E
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1.0 STUDY PLAN INTRODUCTION
A life cycle model (LCM) was proposed by the Aquatics Resources Working Group (ARWG) to
address potential Project impacts to fisheries resources at the population level. Each LCM
scenario will integrate population responses to a range of environmental and Project conditions,
such that we can evaluate the magnitude and likelihood of certain responses associated with the
Project. This study will construct stage-structured population dynamics models that will relate
Project and environmental information to stage transitions (describing movement, survival, and
reproduction) that drive population dynamics (Hendrix et al. 2014, Cunningham et. al 2015).
These models will be used to integrate changes to habitat over time and space to predict the
potential impact to the long-term status of the populations. This study will support the
Cooperative, agencies, and stakeholders in conducting a quantitative risk assessment to decide
what impacts to the populations are acceptable or not acceptable.
2.0 STUDY GOALS AND OBJECTIVES
The primary goal of this study is to:
Develop an LCM for Sockeye and Chinook on the Nuyakuk River that includes
important life stages and is capable of reflecting Project direct and indirect effects.
The primary objectives of this study are to:
Construct a life cycle model that includes the Nuyakuk Hydro Project reach and the life
cycle of these populations.
Develop a life cycle model that can calculate the management relevant metrics and the
magnitude and probability of exceeding management relevant thresholds.
Run the life cycle model for strategic scenarios including current conditions (without-
Project) and current conditions with-Project. Calculate the risk to the population and
fishery (magnitude and probability of exceeding the management thresholds) under these
two scenarios.
Run the life cycle model for strategic scenarios including a baseline future climate
condition (without-Project) and the future climate condition with-Project. Calculate the
risk to the population and fishery (magnitude and probability of exceeding the
management thresholds) under these two scenarios.
Specific questions that will be addressed by this study include:
1. How will Project operations, which affect different stages of the life cycle, be evaluated
for their overall effect on the populations? Project effect questions could include:
a. How will estimated changes to upstream passage, behavior and survival of salmon
through the Falls Reach impact population projections?
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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b. How will estimated changes to downstream passage and behavior of salmon through
the Falls Reach impact population projections?
c. How will estimated rearing habitat changes in the Falls Reach impact the
populations?
d. How will estimated changes to downstream survival impact the populations?
e. How will estimated stranding/trapping rates impact the populations?
f. How will estimated reductions in fringe spawning habitats impact the populations?
g. How will estimated migration delays and injuries due to false attraction to the tailrace
impact the populations?
2. What is the expected natural level of variability (without-Project) in population
dynamics?
3. What is the probability that Chinook and Sockeye salmon escapement will drop below
their escapement goals under the Project compared to without-Project?
4. How will the Nuyakuk River flow and temperature under future climate conditions affect
the population dynamics of Chinook and Sockeye salmon?
5. How will Project operations affect population dynamics and the magnitude and how do
these compare to the population dynamics without-Project under future climate
conditions?
3.0 STUDY AREA
The Sockeye and Chinook LCMs include the full life cycle. Because both species are
anadromous, the LCMs include freshwater and marine habitats. As a result, the Project study
area includes the habitats being used by the Nuyakuk River populations of Sockeye and Chinook
salmon that considers freshwater and ocean habitats used by these species (Figure 3-1).
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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Figure 3-1 Life cycle schematic for a baseline model including the life stages and their location
relative to the Nuyakuk falls.
Direct effects of the Project on fish populations may occur within its hydraulic zone of influence
which is approximately 0.5 miles upstream and downstream of the Nuyakuk Falls. In some
cases, effects in that zone have the potential to influence the abundance and productivity of fish
populations that migrate through or temporarily reside there. Potential impacts can therefore
indirectly influence those populations in time and space outside the Project Area through density
dependent processes that may buffer or amplify direct Project effects on fish population
dynamics. The marine habitats are less specific due to the broad geographic range that Sockeye
and Chinook may inhabit in the marine phase of their life cycle. The geographic area is thereby
described as the migration route over the life history of the population (Nuyakuk, to and through
the ocean, and return to the Nuyakuk) (Figure 3-2).
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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Figure 3-2. Life cycle schematic including life stage, their geographic location, and project effects
on those life stages.
4.0 METHODOLOGY
4.1 Development of life cycle models
Water diversion from the river and through the powerhouse is the fundamental action from
which potential impacts of the Project originate. Water diversion has the effects of reducing
flow through the Falls Reach, creating an additional downstream passage route for fish via the
powerhouse, and relocating bulk flow of the river below the Falls to a localized discharge point
from the tailrace on the right bank of the river. This action primarily affects a 0.34-mile section
of river that comprises the Nuyakuk Falls Reach. These hydraulic changes may also affect the
timing, distribution, passage and survival of resident and migratory fish populations (adults and
juveniles) and their long-term sustainability. Therefore, it is important to understand the impacts
to these populations because of reduced flows through the Falls Reach, entrainment,
stranding/trapping, and migration delays due to false attraction at the tailrace.
For Chinook and Sockeye, the fundamental questions related to this nexus are a) what effect does
the Project have on the number of successful spawners and the number of juvenile outmigrants,
and b) what magnitude and likelihood of this effect is necessary to jeopardize the sustainability
of the populations.
One tool that can be useful in that decision making process is an LCM that provides estimates of
what change in population dynamics are likely under different operational and environmental
conditions. To understand how the Project and its operations may affect the population, it is
prudent to use a model. There are multiple ways in which the Project could potentially impact
the existing populations of Sockeye and Chinook salmon on the Nuyakuk River, and the model
can integrate those processes. The LCMs can perform this integration by incorporating potential
Project effects at different life stages and geographic locations of the population. The LCM
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specifies life stages and tracks the relative abundance in each one of the stages (Hendrix et. al
2014). For example, a simple life cycle might be composed of an adult and a juvenile stage. The
LCM also defines how the abundance changes between stages (so called "transitions"). So, for
the simple model, there would be a transition equation that defines how juveniles survived to the
adult stage, and a second transition equation that defines how adults produced the juveniles.
When the stages are linked into a cycle, then the LCM is capable of modeling multiple cohorts of
animals by repeatedly calculating the abundances of a life stage at a given time via the transition
equations.
Transition equations can also be defined as a function of the abundance in the previous life stage.
For example, in the simple model, the transition that defines the abundance in the juvenile stage
can be affected by the abundance of adults. These density-dependent processes are important in
population dynamics because they can result in one life stage affecting the following life stage in
a non-linear fashion. Density dependence is common in salmonid population dynamics, and thus
a LCM of salmonids should be capable of incorporating density-dependence in the transition
equations.
If the transition equations are static, then the LCM will arrive at an equilibrium abundance for
each stage. On the other hand, if the transition equations are allowed to vary due to the influence
of environmental factors, then the stage abundances will vary through time reflecting the
influence of the environment on the population.
The transition equations can also be allowed to vary using the outputs of other models. These
process-based models may operate on a finer temporal or spatial scale than the LCM and focus
on reflecting the dynamics of a specific process, such as survival or movement. Often these
process-based models incorporate physical driver variables that affect the mechanisms by which
animals survive or move. For example, a model that calculates the time duration it takes an adult
salmon pass through a set of Falls under different flow conditions would be an example of a
process-based model that defines a movement rate. In this manner, the effect of the process-
based drivers can be integrated to understand the population level effects within the LCM.
The steps for developing an LCM that is capable of reflecting Project effects are:
1. Construct an initial baseline LCM that includes current conditions
2. Construct modules that reflect the Project-related effects to different stages of the
population using Project operations as inputs and population level effects on life stage
transition as outputs. For example, given a specific operational scenario a module would
calculate the juvenile survival rate through the Project area.
3. Evaluate the effects of the Project by running the LCM at baseline and running the LCM
with the modules reflecting Project effects for a given operational scenario. Compare the
baseline to the operational scenario.
We are currently in the stage of building the baseline Sockeye LCM. The modules reflecting
Project-related effects are being developed concurrently with the baseline Sockeye LCM, which
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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will allow us to integrate the Project effects over the full life cycle of Nuyakuk Sockeye in the
next year.
4.1.1 Background of Sockeye life cycle model
The Sockeye life cycle is composed of multiple freshwater stages and multiple ocean stages
(Figure 4-1). Sockeye juveniles above the Nuyakuk falls leave the freshwater after rearing for
one (1+ smolts) or two (2+ smolts) winters in the lakes above the Project area. Juveniles spend
between one and three years in the ocean before going through maturation and returning as four-,
five-, and six-year-old adults. When fish return to Bristol Bay, some are harvested in the Sockeye
fishery, whereas others escape the fishery (Escapement) and return up the Nuyakuk River, past
the Project area to the lakes to spawn.
Figure 4-1. Sockeye life cycle model components and potential data available for estimating
transition equations. Shaded boxes indicate potential data that can be collected from the Nuyakuk
and other Sockeye populations in tributaries to Bristol Bay, Alaska. Escapement can be
estimated from tower counts, harvest can be estimated from catch records, 1+ smolts and 2+
smolts can be estimated from juvenile surveys.
4.2 Data acquisition and analysis
The LCM assessment will rely on limited existing information from the Nushagak, other Bristol
Bay watersheds, the evaluation of direct effects and those derived from future flows and
temperature regimes (Wobus et. al 2015), and from the literature. Fish survival information and
escapement estimates do exist for areas upstream and downstream from the Falls that can be
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used as part of this study. New or existing information will be collected by or generated from
the other proposed fisheries studies and/or the broader Revised Study Plan (RSP) for the Project.
The data acquisition has focused primarily on data to relate the number of smolts produced per
spawner. To estimate this relationship, the data must include both the spawning abundance and
the subsequent smolt abundance that was produced. Because smolts outmigrate in multiple
years, the studies must have several important components: 1) a temporal overlap of spawner
sampling and juvenile sampling, 2) a sampling protocol to estimate the abundance of adults
(spawners), 3) a sampling protocol to estimate the abundance of smolts, and 4) a sampling
protocol to estimate the age of juveniles (smolts).
4.3 Linkage with a quantitative risk assessment from the LCM
Managers and stakeholders define the thresholds for abundance or process rates that are being
calculated in the LCM (e.g., survival threshold, productivity threshold, etc.) and the LCM
calculates whether the population exceeds those thresholds. Further, if the LCM includes
stochasticity, then it can be run multiple times under the same environmental and operational
conditions to calculate the magnitude and probability of exceeding those thresholds. In this way,
the LCM can be used to perform a quantitative Integrated Risk Assessment (IRA) when the
threshold values are associated with different levels of risk to the population.
This effort requires that managers and stakeholders define management questions, important
management thresholds, and metrics that are aligned with those thresholds. The following
impact thresholds will be defined in a stakeholder meeting: 1) Project level impacts, 2)
population level impacts, and 3) fishery resource level impacts.
5.0 RESULTS
5.1.1 Sockeye life cycle model
A straw model version of the Nuyakuk Sockeye LCM has been constructed. Outputs from the
model include the harvest of returning salmon and the escapement of adults returning as age-4,
age-5 and age-6 (Figure 5-1). The model is currently constructed to reflect a 30-year time series
with a 6-year initialization period; however the duration of the time series can be altered to
reflect longer time periods (e.g., 50 years). The straw model was constructed with baseline
parameter values that are placeholders for parameters that will be developed over the next year.
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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Figure 5-1. Sockeye straw life cycle model initial outputs include harvest (right) and age-4, age-5,
and age-6 escapement (left) over a 30-year time-period.
5.2 Data acquisition and analysis
Multiple sources have been used to obtain data that is applicable to the Nuyakuk Sockeye
population. To date, there are three populations that have met the five criteria (Section 4.2) for
evaluation of the juvenile production transition. Those populations are Chignik, Afognak, and
Kvichak. In the Chignik population, there are age-0 or young of year outmigrants, whereas in
the Afognak and Kvichak populations the outmigrants are composed of age-1 and age-2 smolts
only. Because the Nuyakuk population is composed primarily of age-1 and age-2 outmigrants,
we have focused our efforts on understanding the production in the Kvichak and Afognak
populations (Figure 5-2).
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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Figure 5-2. Juvenile production of smolts in the Kvichak (top) and Afognak (bottom) Sockeye
populations. Points are the sum of age-1 and age-2 smolts produced by the escapement in the
appropriate brood year.
While the escapement at in the two populations were substantially different, the production of
smolts per adult in the escapement were similar (Figure 5-3). The Kvichak population had a
mean of 13.0 smolts per adult (standard deviation of 6.0), whereas the Afognak population had a
mean of 13.0 smolts per adult (standard deviation 10.0).
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Figure 5-3. Histogram of annual production of age-1 and age-2 smolts per adult in the escapement
in the Kvichak and Afognak populations. Small hash lines on the x-axis indicate the observed
production (smolt/escapement) in each brood year.
Evaluation of density dependence in the juvenile production function can be evaluated by
plotting the log (smolts/escapement) versus the escapement. If there is a negative linear trend in
the plot, this may indicate that there is density dependence that is consistent with a Ricker type
density dependent stock recruitment relationship (Quinn & Deriso 1999). The plot of the
Kvichak population indicates a noisy but negative relationship between the
log(smolt/escapement) and escapement, with the exception of a single year with high escapement
(Figure 5-4). Similarly, the Afognak population indicates a negative relationship between
log(smolt/escapement) and escapement (Figure 5-4).
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Figure 5-4. Test for Ricker type density dependence in the Kvichak (top) and Afognak (bottom)
Sockeye populations by plotting log(Smolts/Escapement) versus Escapement.
5.3 Development of a quantitative risk assessment
The development of a quantitative risk assessment requires input from stakeholders and
managers at a workshop to illicit important thresholds of impacts. This workshop is scheduled
for autumn of 2023, and the results of that workshop to be incorporated into the quantitative risk
assessment framework in the upcoming year. Please see the detailed description of the IRA for
more information on this effort.
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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6.0 DISCUSSION AND FINDINGS
We have developed a straw Sockeye LCM for a baseline Sockeye population. The straw model
is capable of expressing the Sockeye life cycle (e.g, Figure 4-1) in computer code (R
programming language) to predict the harvest and escapement of age-4, age-5, and age-6 adults
(Figure 5-1). This straw model has been parameterized using expert knowledge of Sockeye
salmonid biology, which makes it a somewhat generic Sockeye model. To provide accurate
information the Nuyakuk River population and how it will be affected by the Project, the
baseline straw Sockeye LCM requires additional information.
The parameter values of the straw Sockeye LCM will be improved through several ongoing
efforts. We are actively searching for additional information on Sockeye population vital rates
such as juvenile production by adults, juvenile survival, ocean survival, and harvest rates in the
published and gray literature. Where data can be obtained on juvenile abundances and spawner
abundances (e.g., as described in the data acquisition subtask), these data can be analyzed
statistically to obtain parameter estimates for the transition functions in the LCM (Figure 4-1).
For example, the data obtained from the Kvichak and Afognak populations can be used to 1)
identify a production function (e.g., Ricker) and to estimate the parameters of the juvenile
production function for those two populations. Parameters estimated from those two populations
can be used to inform the production function on the Nuyakuk (e.g., the productivity of the
population in the absence of density dependence).
There is evidence of density dependence in the production of juveniles for populations of
Sockeye salmon (Figure 5-4). Density dependence may also be present in other life cycle
transitions (e.g., the transition of juveniles outmigrating to the ocean). It is important to evaluate
how the straw Sockeye model responds to density dependence in the life stage transitions besides
the juvenile production function, for example in the juvenile outmigration stages (Figure 6-1).
We will evaluate the sensitivity of the population outputs (escapement and harvest) to different
levels of density dependence in the coming year to better understand how the Nuyakuk
population may respond to the hydro Project effects on the juvenile and adult life stages (e.g.,
Figure 3-2).
Finally, the straw Nuyakuk Sockeye baseline model is deterministic due to the model using fixed
parameter values. The Sockeye LCM that will be used to evaluate the Project will include
uncertainty in the parameter estimates to reflect the uncertainty in current knowledge in the
transition functions. For example, a Ricker type production function can be defined for the
Nuyakuk sockeye population, but the parameters of that production function are then described
by probability distributions instead of a single value. These distributions will be defined over the
next year to appropriately quantify uncertainty in the transition equations (Figure 4-1).
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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Figure 6-1. Sockeye life cycle model components and potential data available for estimating
transition equations. Potential locations of density dependence (DD) in the life cycle is shown as
blue circles.
7.0 STUDY VARIANCES AND MODIFICATIONS
The life cycle model study was structured via a set of seven tasks described in the Revised Study
Plan (RSP). The only study variance was the addition of an LCM modeling task summarized
below.
Supplemental Life Cycle Modeling Task - Management metrics
Define management questions, important endpoints, and metrics that are aligned with those
endpoints. The management questions should include: Project level impacts, population level
impacts, and fishery resource level impacts. This task should include input from stakeholders and
decision makers.
8.0 STUDY STATUS AND SCHEDULE
There are multiple tasks for completing the life cycle models and the evaluation of the Project on
the Nuyakuk populations of Sockeye and Chinook that are still ongoing. All remaining tasks
will be completed in Year 2 of the study program and be included as a part of the Updated Study
Report (USR) in December of 2024.
Nuyakuk River Hydroelectric Project Sockeye and Chinook Life Cycle Models
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9.0 STUDY-SPECIFIC CONSULTATION
Model development began during Year 1 has included monthly technical consultation meetings.
Primary meeting members included: 1) Mary Louise Keefe of Klenschmidt Associates, 2) Noble
Hendrix from QEDA Consulting, and 3) Bryan Nass of Bristol Bay Science and Research
Institute (BBSRI). These meetings ceased following the completion of the baseline LCM for
Nuyakuk Sockeye.
10.0 REFERENCES
Cunningham, C., N. Hendrix, E. Dusek-Jennings, R. Lessard, and R. Hilborn. 2015. Delta
Chinook Final Report. DOI:10.13140/RG.2.1.4800.3282
Hendrix, N., A. Criss, E. Danner, C.M. Greene, H. Imaki, A. Pike, S.T. Lindley. 2014. Life
cycle modeling framework for Sacramento River winter-run Chinook salmon. NOAA-
TM-NMFS_SWFSC-530.
Quinn II, T. J. and R. B. Deriso. 1999. Quantitative Fish Dynamics. Oxford University Press.
Wobus, C., R. Prucha, D. Albert, C. Woll, M. Lionaz, R. Jones. 2015. Hydrologic alterations
from climate change inform assessment of ecological risk to pacific salmon in Bristol
Bay, Alaska. PLoS ONE 10(12): e0143905. doi:10.1371/journal.pone.0143905.
INITIAL STUDY REPORT
ATTACHMENT F: INTEGRATED RISK ASSESSMENT OF FISH POPULATIONS
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
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TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 2
5.0 RESULTS........................................................................................................................... 4
6.0 DISCUSSION AND FINDINGS........................................................................................ 4
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 4
8.0 STUDY STATUS AND SCHEDULE................................................................................ 5
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 5
10.0 REFERENCES ................................................................................................................... 5
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ACRONYMS AND ABBREVIATIONS
ABM Agent-Based Model
ARWG Aquatics Resources Working Group
BBSRI Bristol Bay Science and Research Institute
Commission Federal Energy Regulatory Commission
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
IRA Integrated Risk Assessment
LCM Life Cycle Model
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USR Updated Study Report
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1.0 STUDY PLAN INTRODUCTION
An Integrated Risk Assessment (IRA) was proposed by the Aquatics Resources Working Group
(ARWG) to evaluate potential Nuyakuk River Hydroelectric Project (Project) impacts to
fisheries resources at the population/ fish-community level. The IRA will integrate population
responses to a range of environmental and Project conditions or scenarios. This assessments will
allow the Cooperative, agencies, and stakeholders to decide what impacts to the populations are
acceptable or not.
The Federal Energy Regulatory Commission (FERC) approved the IRA study plan to develop a
semi-quantitative evaluation of risk that integrates the accumulated knowledge from available
expert, local, and empirical sources. This will range from professional judgement for target fish
species to the development of a quantitative Life Cycle Model (LCM) for Sockeye and Chinook
salmon. The ultimate outcome is to have a ranked risk assessment that highlights the most
substantive risk issues in need of further evaluation and mitigation. Year 1 execution of the
Revised Study Plan (RSP) included continued consultation with the ARWG to define
management objectives and priorities for development of the IRA.
2.0 STUDY GOALS AND OBJECTIVES
The intent of this study is to provide a framework for quantifying and/or qualifying the relative
risk of Project-related impacts to fish population dynamics over the course of the lifecycle of
fish, and over the life of the Project. This assessment will address target fish species including
Pacific Salmon, other migratory fishes and resident fish species that utilize the Project Area.
The primary goal of this study is to:
Develop integrated risk assessments for all aquatic species of management interest
that are potentially affected by the Nuyakuk Project. Quantify the risk (magnitude and
probability of surpassing management defined thresholds) of impact by the proposed
Nuyakuk Project and operations on Chinook and Sockeye population dynamics under
baseline and future climate conditions. Qualify the risk for all other target species of
management concern.
The primary objectives for this study are to:
Quantification of Risk
Develop a set of management relevant metrics that reflect: 1) the Nuyakuk population
level impacts on the Nushagak fishery, 2) population variability in the Nuyakuk.
Identify a set of management relevant thresholds for the metrics that constitute “risk”,
such that exceeding those thresholds could have a significant negative impact on the
population.
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Conduct a quantitative risk evaluation using LCM output relevant for Sockeye and
Chinook salmon by management objective, elements, and risk sources.
Qualification of Risk
Define the management objectives for the fish population/community, which could be
a single objective for each species, or could be multiple objectives for some species
(i.e., what is at risk? abundance, sustainability). The management objectives have
respective elements (e.g., habitat, predation, passage) that can influence achieving the
objectives, and indicators (metrics for survival, passage success, habitat suitability,
injury/stress) that measure change to the elements.
Define specific risk sources (Project structures or operations, climate change
variables).
Define risk ranking criteria (thresholds of consequence and likelihood).
Convene a workshop(s) with agencies and stakeholders (public) for input on
objectives and risk analysis. Refine risk analysis as needed.
Conduct a qualitative risk evaluation (e.g., low, moderate, high) for target species, by
management objective, elements, and risk sources. Analyses will rank the potential
impact of risk sources on the target species population. This approach to assessing
risk is particularly useful for species for which there are too few data to develop a
reasonable LCM.
3.0 STUDY AREA
Direct effects of the Project to fish populations may occur within its hydraulic zone of influence
which is approximately 0.5 miles upstream and downstream of the Nuyakuk Falls. Effects that
may occur within that zone also have the potential to influence the abundance and productivity
of fish populations that migrate through, or temporarily reside, there. Thus, this study will also
consider relevant impacts that have the potential to indirectly influence populations outside the
Project area. These density dependent processes may buffer or amplify direct Project effects on
fish.
4.0 METHODOLOGY
Within the integrated risk assessment framework for Nuyakuk River fish populations, the
question to be addressed is: What is the risk to achieving management objectives for fish species
present in the Project area, considering all activities involved with the Project and other risk
sources such as climate change?
To answer that question, several steps are required:
1. Define management objectives or questions for each target species;
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2. Identify the potential risk sources from the Project and environment (e.g., climate) to
achieving species management objectives;
3. Identify the elements that are measured as indicators of impact to a population;
4. Gather, collect, evaluate, and analyze available knowledge on the likelihood and
magnitude of impact from each potential risk to each management objective;
5. Developing and implementing an appropriate method for summarizing identified risks
into a semi-quantitative scale; and
6. Evaluate the potential risk of Project and environmental factors affecting fish populations.
In Year 1 (2023), the Cooperative was focused on the development of a proof-of-concept IRA
model for Sockeye Salmon. Steps 1 through 5 have been initiated and through the fall and winter
of 2023, the Cooperative will convene a series of meetings and workshops with the AWRG to
complete steps 1, 2, and 3. Under Step 1, clear management objectives or questions for each
population must first be established. For example, the management objectives for this Nuyakuk
River fisheries risk assessment might include a particular population abundance or escapement
number for each species present in the system, or it might be a more general objective of
sustainable populations.
In support of Steps 2 and 3, the Cooperative will develop drafts of the potential risk sources and
elements that are ecosystem-based and are appropriate for Nuyakuk Sockeye Salmon within the
Project area and will work with the ARWG for refinement. A risk source is an internal or
external situation that gives rise to a risk when combined with certain conditions or events. For
example, hydroelectric facility operation is a potential source of entrainment risk to salmon
migrating downstream past the Project. Climate change is also an example of a potential source
of risk that may have multiple elements or indicators for fish in the Project area. Following the
identification of risk sources, indicator elements will be selected to represent processes,
conditions, and Project effects. Risk elements are specific aspects or components associated with
a risk source that can contribute to the manifestation of risk, i.e., a change in flow regime due to
the operation of the Project.
The summer of 2023 saw the collection and gathering of data (literature and field-based) and 2D
flow model development as defined in the RSP. This included data on Sockeye Salmon smolt
outmigration and adult returns in other Alaska river systems as well as the collection of telemetry
data on Sockeye Salmon passage in the Project area. Under this IRA study, workshops with
stakeholders will augment these expert and empirical data sources with local knowledge and will
be used to inform our assessment of risk.
Developing an appropriate methodology for implementing an IRA with a common scale is a
major task of this study, and as such, was initiated by the Cooperative in Year 1. During this
time, we reviewed numerous fisheries risk assessments in the literature with which we have
refined a Qualitative Integrated Risk Analysis process (Bradford 2020; Fletcher 2015; Gaichas et
al. 2018). Management objectives and risk sources form the basis of a risk assessment summary.
Management objectives are clear, concise, and specific goals related to the management and
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mitigation of identified risks. During the end of Year 1 and the beginning of Year 2, we will
complete the development and implementation of the appropriate method for summarizing
identified risks into a semi-quantitative scale for the Sockeye Salmon proof-of-concept. We
anticipate development of a separate risk matrix for each management objective. This is where
we determine the magnitude of potential consequences to the objective and the likelihood that
those consequences will occur under planned operations for each objective-risk element pair.
Data from indicator metrics will support the evaluation. For this analysis, we will rely heavily on
outputs of the 2D flow model, the Sockeye Salmon ABM, and ultimately the Sockeye Salmon
LCM (Attachment E) as well as available data from other hydroelectric projects. The following
are important considerations that will be addressed while completing the risk analysis.
1. Consequences must be viewed as potential consequences to the overall stated
management objective. This step ensures a common currency amongst species and risk
sources. For example, an increase in mortality is not necessary concerning, if the level of
expected mortality would not constitute a major impact to the sustainability of a
population (if that is the decided objective).
2. It is important to assess the risk associated with an issue even when there is a perceived
lack of information. Otherwise, the current level of action or inaction is, by default, rated
as acceptable. The approach outlined here can incorporate clear uncertainties into the
justifications for the final scores that are selected. The justifications should include a
detailed narrative that refers to, and to the extent possible, is consistent with available
lines of evidence, including their levels of uncertainty.
5.0 RESULTS
Workshops to identify management objectives, risk sources and their elements have not yet
convened (scheduled for December 2023) and therefore, no draft or refined IRA results or the
documentation of interim steps are available at this time. A comprehensive report in support of
the development and results for the IRA will be incorporated into the Updated Study Report
(USR).
6.0 DISCUSSION AND FINDINGS
No discussion of IRA results or findings are available at this time. A comprehensive report in
support of the development and results for the IRA will be incorporated into the USR.
7.0 STUDY VARIANCES AND MODIFICATIONS
No variances have been noted during Year 1 of the study.
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8.0 STUDY STATUS AND SCHEDULE
Workshops to identify management objectives, risk sources and their elements will begin in
November and December of 2023. Risk analysis will be conducted in spring and summer of
2024, with an identification of risk elements for mitigation and monitoring summarized into the
USR in December of 2024.
9.0 STUDY-SPECIFIC CONSULTATION
The need for an IRA and framework for both model development, and how the results of other
component models of the Fish and Aquatics Program (i.e., 2D model [Attachment B], Agent
Based Model [Attachment B], the Sockeye and Chinook LCM [Attachment E]) will be integrated
into the IRA has been the topic of collaborative discussions amongst the Cooperative’s team and
the ARWG during development of the Proposed Study Plan and RSP.
Model development began during Year 1 studies, and to date has included two consultation
meetings that included a member of the ARWG and Bryan Nass at Bristol Bay Science and
Research Institute (BBSRI). These meetings occurred as follows. Meeting notes and presentation
materials are available via request of the Nushagak Cooperative.
Wednesday August 30, 2023 8-9 am (PST)
Kevin Nebiolo provided a presentation and draft framework for IRA risk assessment
categories, and the group began discussion how to establish a list of risk factors to consider for
inclusion in the IRA. The group also reviewed the objectives for the IRA introduced in the RSP.
Wednesday September 6, 2023 8-10 am (PST).
During this follow-up meeting from August 30, 2023, Kevin Nebiolo provided a
presentation and draft framework for IRA risk categories and the group discussed how to
establish a list of risk factors to consider for inclusion in the IRA. The group discussed how to
define terms for general understanding and to develop a plan for soliciting input from the broader
ARWG on management objectives that will further direct the development of a list of risk factors
to include in the IRA.
10.0 REFERENCES
Bradford, M.J. 2020. Assessment and management of effects of large hydropower projects on
aquatic ecosystems in British Columbia, Cananda. Hydrobiologia, 17.
Fletcher, W.J. 2015. Review and refinement of an existing qualitative risk assessment method for
application within an ecosystem-based management framework. ICES Journal of Marine
Science.
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Gaichas, S.K., G.S. DePiper, R.J. Seagraves, B.W. Muffley, M.G. Sabo, L.L. Colburn, and A.J.
Loftus. 2018. Implementing Ecosystem Approaches to Fishery Management: Risk
Assessment in the US Mid-Atlantic. Frontiers in Marine Science, 5, 25.
INITIAL STUDY REPORT
ATTACHMENT G: FUTURE FLOWS STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
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TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 2
2.1.1 Study Goals and Objectives........................................................................ 2
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 4
4.1 Downscaled GCM Outputs..................................................................................... 6
4.2 Hydrologic Modeling.............................................................................................. 7
4.3 Technical Report ..................................................................................................... 7
5.0 RESULTS ........................................................................................................................... 8
6.0 DISCUSSION AND FINDINGS........................................................................................ 8
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 8
8.0 STUDY STATUS AND SCHEDULE................................................................................ 8
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 8
10.0 REFERENCES ................................................................................................................... 8
LIST OF FIGURES
Figure 3-1. Nuyakuk River watershed. ............................................................................................3
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ACRONYMS AND ABBREVIATIONS
ASCE American Society of Civil Engineers
BOR Bureau of Reclamation
CMIP Climate Model Intercomparison Project
Commission Federal Energy Regulatory Commission
Falls Nuyakuk Falls
FEMA Federal Emergency Management Agency
FERC Federal Energy Regulatory Commission
GCM Global Climate Models
IPCC Intergovernmental Panel on Climate Change
NMFS National Marine Fisheries Service
NOAA National Oceanic and Atmospheric Administration
Project Nuyakuk River Hydroelectric Project (P-14873)
USACE U.S. Army Corps of Engineers
USDOE U.S. Department of Energy
USR Updated Study Report
WUCA Water Utility Climate Alliance
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1.0 STUDY PLAN INTRODUCTION
The Nuyakuk River Hydroelectric Project (Project) has the potential to be designed and operated
in a manner that maintains habitat quality and suitability for the fish and provides renewable
hydropower for six Alaskan communities currently dependent on diesel for power generation. To
realize the combined benefits, it is necessary to understand the consistent projection of increases
in precipitation and the changing timing of flows in the Nuyakuk watershed. Therefore, existing
peer reviewed climate model predictions will be used to model future discharges and water
temperatures for the Nuyakuk River, in accordance with peer- reviewed published methods and
generally accepted practice as described below. This information will inform the development of
license articles guiding operation and maintenance, including mitigation measures, as well as the
development of a climate resilient project design.
The best available science indicates temperature, precipitation, and stream flows will increase in
the Bristol Bay region, and much of south-central Alaska (IPCC 2018; Walsh et al. 2018;
USGCRP 2018; Chapin et al. 2018). Thus, higher stream flows are likely to occur within the
project area during the prospective license term. Some ongoing trends and anticipated climate
changes have implications for management of the hydropower facility and fish habitat. These
include a decrease in the proportion of precipitation falling as snow, with many sub-basins no
longer expected to be snow-dominated (Littell et al 2018), and as a consequence, an altered
hydrograph with earlier but perhaps lower spring/summer peak. January through April flows will
continue to increase as low elevation sub-basins partially melt out during freshets rather than
staying frozen for four continuous months. Peer-reviewed, publicly available downscaled climate
model projections have been developed for this region. These model projections will be analyzed
as part of this licensing process to support flow analysis for this project. There is a significant
body of literature on climate change in the Arctic and Alaska in particular (Stewart et al 2022,
Markon et al 2018). While these publications give a sense of what kinds of changes may be
observed in the Nushugak River, due to proximity, analysis of a region including this basin, and
other similarities, a study of the Nuyakuk basin itself is needed to understand the combined
changes of the proposed project and climate change on fish habitat.
Salmonids are affected by changes in flows because stages in their life history are timed to
coincide with periods of flow and appropriate water temperature. Future flows through the
Nuyakuk cascade will be altered by the Project’s water withdrawal and by changing climate
patterns. Many of the climate change effects described below have likely impacts on salmonids
(Leppi et al 2014; Wobus et al 2015) and are potentially compounded by the proposed Project’s
operations. Given that increased flows are projected by the five-member ensemble of global
climate models (GCM) best fitted for Western Alaska, these increases provide opportunities to
benefit both the hydropower generation and fish management and protection. Therefore, it is
critical to have estimates of future flows and stream temperatures to assess the combined effects
of the project and climate on these trust resources. This study is at the core of producing more
evenly distributed year-around hydropower generation, while at the same time protecting and
maintaining this salmon fishery. This is in line with recent literature that highlights opportunities
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to design and operate hydropower projects for sustainability of both power production and the
riverine environment (Brown et al. 2015; Poff et al. 2016). Thus, this study will identify forward-
looking, climate resilient outcomes for hydropower development and fisheries.
2.0 STUDY GOALS AND OBJECTIVES
2.1.1 Study Goals and Objectives
The goals of this study are to determine mean flows and water temperature during the assumed
50-year term of the license, at least at a monthly time scale, and weekly or daily if feasible.
Details of the study are provided in the § 5.9 (b) Generally Accepted Practices section below.
National Oceanic and Atmospheric Administration (NOAA) Fisheries and its NOAA climate
science partners are available and willing to discuss the details of the climate and flow studies to
ensure its value for all parties. We assume a 50-year license will be issued, and total project
development time of eight years, so we propose projecting the climate from 2030 to 2080. The
objectives of this study are:
1. Use existing downscaled climate projections preferably supplied by University of Alaska,
Fairbanks (Walsh et al 2018; Wobus et al 2015) to model and predict Nuyakuk River
flow and temperatures during the license term. These should be done at least at a monthly
time scale and weekly or daily if feasible.
2. Use this information to determine the future timing of returning adult salmon and when
water will be needed in the river to support fish passage both up and down the falls. This
information will inform the Nuyakuk Falls Fish Passage (Study 1.2); Assessment of False
Attraction (Study Request 1.4); Chinook and Sockeye Salmon Life Cycle Modeling
(Study 1.5) and the Economic Decision Support Tool.
3. Use this information to project timing of out-migrating smolt. This information will
inform the Ice Process (Study 2.3) and Fish Entrainment and Impingement (Study 1.3).
4. Use future flow information to inform turbine sizing and winter, spring and fall energy
production.
5. Use future flow information to inform project design and operation including tunnel
design, groin design, and any attempt to mesh winter hydropower with other electric
generation facilities to meet domestic winter power demands of the six communities.
3.0 STUDY AREA
The future river flows and water temperature study is a desktop exercise. The assessment will
encompass the Nuyakuk River watershed with an approximate drainage area of 1,571 square
miles (Figure 3-1).
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Figure 3-1. Nuyakuk River watershed.
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4.0 METHODOLOGY
It has become generally accepted practice to consider climate change in hydropower design
among planners and designers of hydropower and water supply facilities. The best available
science now includes the presently observed and projected future impacts of climate change on
water resources, as demonstrated by Congress directing the Secretary of Interior, via the Secure
Water Act, to coordinate with NOAA and its programs to ensure access to the best available
information on climate change [Secure Water Act (§) 9503 (c)]. The following are examples -
dating back more than fifteen years - from water projects such as Nuyakuk and others permitted
by the Federal Energy Regulatory Commission (FERC) - in which managers and planners
incorporate the risks of climate change in their project design of projects, as well as in long-
range operations planning:
The U.S. Bureau of Reclamation (BOR) and Army Corps of Engineers (USACE)
both use climate projections in their long-range operations planning and design,
including hydropower generation, flood control, and water supply. These agencies
jointly commissioned and released a report that identifies the needs of local, state, and
federal water management agencies for climate change information and tools to
support long-term planning (Brekke 2009). Beginning more than a decade ago,
USACE and BOR and a consortium of agencies funded downscaled hydrologic
projections for use in planning for reservoirs and hydropower operations (Bureau of
Reclamation 2009, Dalton et al 2010). The BOR-funded project was then
subsequently updated for the next generation of IPCC global climate models (CMIP5,
Brekke 2013, Pierce et al. 2015). These flow projections are currently being updated
using the CMIP6 GCMs.
The River Management Joint Operating Committee for Bonneville Power
Administration, USACE, and BOR commissioned climate scenarios for use (River
Management Joint Operating Committee, 2010, a-c). The plans for this were
published as a peer-reviewed article (Hamlet, et al 2013).
Non-Federal facilities are also being designed and managed with consideration of
climate risks. The Water Utility Climate Alliance (WUCA) includes twelve of the
Nation's largest water providers, many of which manage hydropower facilities. It was
formed to provide leadership and collaboration on climate change issues affecting the
country's water agencies. Among WUCA’s key messages is, “Warming is here and
now. Climate adaptation planning is not just about the future. Water utilities are
experiencing the effects of a changing climate on their water resources today.”1
WUCA and its member cities advocate the use of climate projections and planning
for a range of futures (Stratus Consulting and Denver Water 2015, Vogel et al. 2015).
1 www.wucaonline.org
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The American Society of Civil Engineers (ASCE) recommended the use of climate
change in design criteria. In a policy statement originally approved in 1990,
(PS360)2, ASCE highlighted the importance of climate change on the built
environment. This policy has been revised and adopted several times since then. In
2018 it indicated a growing need for engineers to incorporate future climate change
into project design criteria, and in 2021, support for “Revisions to engineering design
standards, codes, regulations and associated laws that strengthen the sustainability
and resiliency of infrastructure at high risk of being affected by climate change.”3
A growing body of U.S. policy requires and provides guidance on consideration of climate risks
and use of climate information by federal agencies. In addition to the Secure Water Act, this
includes Executive Orders dating back to 2009 have directed federal water and hydropower
agencies such as the BOR, USACE and Department of Energy (USDOE) to consider climate
change in their projects (Executive Order (EO) 13514, replaced by EO 13693, titled Planning for
Federal Sustainability in the Next Decade, March 19, 2015). On Dec 8, 2021, President Biden
signed EO 14057 4, which orders agencies to integrate climate-readiness across missions and
programs and bolster resilience of Federal assets, including hydropower facilities 5. Federal
agencies have increasingly considered the risks of climate change (e.g. NMFS 2016 and Udall
2013). The downscaled climate projections follow in this tradition, based on the same IPCC
global climate models. In particular, the University of Alaska Fairbanks’ Alaska Climate
Research Center (http://akclimate.org/) has produced the Scenarios Network for Alaska and
Arctic Planning (SNAP, https://www.snap.uaf.edu).
In FERC’s Order rejecting the request for rehearing by National Marine Fisheries Service
(NMFS) and the Center for Water Advocacy of the formal study dispute determination regarding
Susitna (July 18, 2014), FERC stated, “as climate change modeling continues to advance, it may
eventually yield data and knowledge that can and should be used to formulate license
requirements that respond to environmental effects caused by climate change.” That time has
come. Another generation of Intergovernmental Panel on Climate Change (IPCC) models (IPCC
2021) has consistent findings - albeit further refined - with previous IPCC (IPCC 2013 and IPCC
2007) and U.S. National Climate Assessment analysis, while also providing more detailed and
relevant information for natural resource planners. Climate modeling and especially downscaling
methodology has improved significantly in the last decade. Furthermore, in the last five years
climate change effects have been acknowledged across all departments of the State of Alaska
Government. Downscaled climate projections datasets developed for Alaska (Walsh 2018) and
2 https://www.asce.org/advocacy/policy-statements/ps360---climate-change
3 https://www.asce.org/advocacy/policy-statements/ps360---climate-change
4 https://www.whitehouse.gov/briefing-room/statements-releases/2021/12/08/fact-sheet-president-bidensigns-
executive-order-catalyzing-americas-clean-energy-economy-through-federalsustainability/#:~:
text=The%20executive%20order%20will%20reduce,%2C%20healthy%2C%20and%20resilient%2
0communities
5 https://www.whitehouse.gov/briefing-room/statements-releases/2021/10/07/fact-sheet-bidenadministration-
releases- agency-climate-adaptation-and-resilience-plans-from-across-federal-government/
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elsewhere are being used as generally accepted practice in the design and operational planning
for hydropower. This study takes into consideration the advances in science, the generally
accepted practice, and understanding both the risks of climate change and the potential
opportunities of the projected increases in temperature and precipitation and the effects on
managing flows both for hydropower and fish habitat.
The steps and data available to do these analyses are described below. New climate modeling is
not needed. Rather, analyses of existing, publicly available and peer-reviewed datasets will be
conducted based on existing Climate Model Intercomparison Project (CMIP) dataset, using peer-
reviewed and generally accepted practices, as described in those articles and cites therein.
The basic analysis that is needed is to move from downscaled GCM projections of temperature
and precipitation to projected flows and water temperatures from a integrated hydrologic model
for the Nuyakuk River specifically. The hydrologic modeling will then be analyzed and
presented in a technical report of the future flows available, and thus the hydropower and fish
habitat needs. Additionally, this report will include an analysis of the impacts of projections on
the project nexus, and hydropower facilities. The three major steps are summarized in Sections
4.1 to 4.3.
4.1 Downscaled GCM Outputs
Use of the dataset described by Walsh et al (2018), an existing, peer-reviewed and publicly
available monthly downscaled climate projection dataset, and related data. Scenarios Network
for Alaska and Arctic Planning (SNAP), along with related data is available for download at:
https://www.snap.uaf.edu. This dataset is based on the 5th IPCC generation of global climate
models (CMIP5). Walsh et al (2018) analyzed the over 35 GCMs to assess which five best
represent climates in Alaska as a whole. See (Lader 2017) or (Bieniek et al. 2015) for a more
detailed description of the downscaling model procedure and an evaluation against historical
temperature and precipitation data. Their product provides monthly values of projected future air
temperature and precipitation. Monthly values are the minimum needed for analyses of future
flows but may average out changes. Wobus et al (2015) generated daily values, and thus were
able to discern shorter time scale features in river flows. If technically feasible and available for
the Nuyakuk River, this daily scale is preferable because of the finer time scale changes that
daily analyses would detect.
Because 30 months have passed since this study was originally proposed (2/4/2020), new
downscaling efforts are underway and downscaled CMIP 6 climate products may become
available before this study is started. Furthermore, a dynamically downscaled product for all of
Alaska may be available soon. If by the time this study is executed, a sub-monthly or daily
downscaled product is available, that would be preferable. If a CMIP6-based appropriate
downscaled product becomes available, that product may be used instead of the Walsh et al 2018
dataset. However, it is not necessary to wait for CMIP6.
Predicted temperatures and precipitation will be analyzed for at least three periods of the license,
for example, early, the first third (e.g. 2030 – 2047); the middle third, (e.g. 2047-2064); and the
late or final third (e.g. 2064 to 2080) for the Nuyakuk watershed. This will allow consideration
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of flow trends that may evolve over the period, and potentially different operations as projected
conditions change.
4.2 Hydrologic Modeling
A published, vetted hydrologic model will be used to translate these downscaled climate outputs
(precipitation and temperature) into other hydroclimate variables (evaporation, soil percolation,
surface runoff) and ultimately the timing and volume of runoff into the Nuyakuk River, and
stream temperatures. Several watershed models that integrate atmospheric conditions with
surface water and groundwater could be applied to the Nuyakuk watershed; however, they would
require extensive development.
We will use the MIKE SHE system (Graham and Butts 2005), a fully distributed, parameter
integrated, hydrologic code that simulates the flow of water within and among surface water,
groundwater, and the unsaturated zone. Atmospheric conditions, including precipitation, air
temperature, and evapotranspiration drive continuous flows within the hydrologic system. A
modified degree-day snowmelt method, the code simulates snow accumulation if air
temperatures fall below a freezing threshold, and it also simulates snowmelt processes including
evaporation (sublimation and wet- snow evaporation), rain-on-snow, changes in wet and dry
snow storage, and refreezing of wet snow. The Wobus et al (2014) effort, also implemented a
heat balance algorithm to simulate stream temperatures (Loinaz et al. 2013). The hydrologic
models then projects monthly (or daily) water temperatures based on predicted air temperature
and the relative river contributions from surface water versus groundwater sources versus
snowfields sources.
Furthermore, the MIKE/SHE system is useful because Bristol Bay Regional Seafood
Development Association and Bristol Bay Native Corporation already funded the development
of an integrated watershed model for the Nushagak watershed using MIKE/SHE MIKE 11 code
developed by the Danish Hydrologic Institute (DHI). MIKE SHE has been used and verified
extensively worldwide and in the U.S. since the mid- 1970s, by multiple federal agencies
including USACE, Federal Emergency Management Agency (FEMA), USDOE, (United States
Department of Agriculture) USDA, academic researchers and others to support evaluation of
complex networks of hydraulic structures and operations, nature and extent of impacts on
hydrologic/ecologic systems, and optimization of mitigations. As a cost saving measure, we will
adapt the existing larger Nushagak model to the Nuyakuk watershed.
4.3 Technical Report
The potential climate change effects will be summarized in a Technical Report. This technical
report will include a description of the assumptions made, models used, and other background
information. The report will provide interpretation and guidance on the science knowledge
developed, in order to translate them into useable knowledge, through syntheses and translational
products developed to address the hydropower, water, and fisher habitat needs. Additionally, this
report will include an analysis of the impacts of projections on the project nexus, and
hydropower facilities. The report will include an electronic supplement that makes the data used
in this study available for the use of other studies.
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5.0 RESULTS
While future flows modeling efforts and synthesis with other biological modeling was initiated
in 2023, results from relevant natural and Project-related scenarios will be developed and
assessed during the remainder of 2023 and into 2024. Holistic results will be presented as part of
the Updated Study Report (USR) in December 2024.
6.0 DISCUSSION AND FINDINGS
While future flows modeling efforts and synthesis with other biological modeling was initiated
in 2023, results from relevant natural and Project-related scenarios will be developed and
assessed during the remainder of 2023 and into 2024. Holistic results and associated impact
discussion will be presented as part of the USR in December 2024.
7.0 STUDY VARIANCES AND MODIFICATIONS
While future flows modeling efforts and synthesis with other biological modeling was initiated
in 2023, results from relevant natural and Project-related scenarios will be developed and
assessed during the remainder of 2023 and into 2024. Holistic results and associated impact
discussion will be presented as part of the USR in December 2024. To date, no variances
associated with the Future Flows Study have been identified.
8.0 STUDY STATUS AND SCHEDULE
The Future Flows Study is currently on schedule to be completed in 2024 and reported on as part
of the USR.
9.0 STUDY-SPECIFIC CONSULTATION
A complete list of all relevant study-specific consultation related to the Future Flow Study will
be included in the USR.
10.0 REFERENCES
Bieniek, P.A., Bhatt, U.S., Walsh, J.E., Rupp, T.S., Zhang, J., Krieger, J.R., and Lader, R. 2015.
Dynamical Downscaling of ERA-Interim Temperature and Precipitation for Alaska.
Journal of Applied Meteorology and Climatology 55(3): 635-654. doi:10.1175/JAMC-D-
15-0153.1.
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Brekke, L. D., Maurer, E. P., Anderson, J. D., Dettinger, M. D., Townsley, E. S., Harrison, A., &
Pruitt, T. 2009. Assessing reservoir operations risk under climate change. Water
Resources Research, 45. doi:Artn W0441110.1029/2008wr006941
Bureau of Reclamation. 2009. West-Wide Climate Risk Assessments: Bias-Corrected and
Spatially Downscaled Spatially Downscaled Surface Water Projections. Department of
Interior, Denver, Colorado
Dalton, J. C., Brown, T. A., Pietrowsky, R. A., White, K. D., Olsen, J. R., Arnold, J. R., . . . Raff,
D. A. 2010. US Army Corps of Engineers Approach to Water Resources Climate Change
Adaptation. Climate: Global Change and Local Adaptation, 401-+. doi:10.1007/978-94-
007- 1770-1_21
Hamlet, A.F., Elsner, M.M., Mauger, G.S., Lee, S.-Y., Tohver, I., and Norheim, R.A. 2013. An
Overview of the Columbia Basin Climate Change Scenarios Project: Approach, Methods,
and Summary of Key Results. Atmosphere-Ocean 51(4): 392-415.
doi:10.1080/07055900.2013.819555.
IPCC (Intergovernmental Panel on Climate Change). 2021. Summary for Policymakers. In:
Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to
the Sixth Assessment Report of the Intergovernmental Panel on Climate Change
[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y.
Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews,
T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge
doi:10.1017/9781009157896.001.
IPCC. 2018. Summary for Policymakers. In: Global warming of 1.5°C. An IPCC Special Report
on the impacts of global warming of 1.5°C above pre-industrial levels and related global
greenhouse gas emission pathways, in the context of strengthening the global response to
the threat of climate change, sustainable development, and efforts to eradicate poverty
World Meteorological Organization: 32 pp.
IPCC. 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group
I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.
Cambridge University Press, Cambridge, UK and New York, NY. Available:
http://ipcc.ch/report/ar5/wg1/
IPCC. 2007. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of
Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change. Cambridge University
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Climate Extremes for Alaska via Dynamical Downscaling and Quantile Mapping. Journal
Nuyakuk River Hydroelectric Project Future Flows Study
FERC No. 14873 Initial Study Report – Attachment G
Nushagak Cooperative, Inc. December 2023
of Applied Meteorology and Climatology 56(9): 2393-2409. doi:10.1175/jamc-d-16-
0415.1.
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pr_climate_change_guidance_june_2016.pdf Accessed 6/28/2022
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INITIAL STUDY REPORT
ATTACHMENT H: WATER QUALITY ASSESSMENT
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 2
4.1 Water Temperature ................................................................................................. 2
4.2 Dissolved Oxygen................................................................................................... 2
5.0 RESULTS ........................................................................................................................... 4
5.1 Dissolved Oxygen................................................................................................... 4
5.2 Water Temperature ................................................................................................. 4
6.0 DISCUSSION AND FINDINGS........................................................................................ 6
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 7
8.0 STUDY STATUS AND SCHEDULE................................................................................ 7
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 8
10.0 REFERENCES ................................................................................................................... 8
LIST OF FIGURES
Figure 3-1. Water Quality Assessment Monitoring Locations. .......................................................3
Figure 5-1. Nuyakuk River Water Quality Data - Dissolved Oxygen.............................................4
Figure 5-2. Nuyakuk River Daily Maximum Water Temperatures (July 24, 2018 – January
4, 2021) - Project site and USGS 1530200. .............................................................5
Figure 5-3. Nuyakuk River Daily Maximum Water Temperatures (June 1 – September 30,
2022) – NETC Project site and USGS 1530200. .....................................................6
LIST OF TABLES
Table 1-1. ADEC criteria for water use category (C) ......................................................................1
Table 4-1. Summary of DO spot calibration checks vs, continuous loggers. ..................................2
Table 6-1. Daily average DO concentrations upstream and downstream of the proposed
Nuyakuk Falls Project site. ......................................................................................7
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. ii December 2023
ACRONYMS AND ABBREVIATIONS
ADEC Alaska Department of Environmental Conservation
ADFG Alaska Department of Fish and Game
Commission Federal Energy Regulatory Commission
DO dissolved oxygen
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ft foot
IRA Integrated Risk Assessment
IM Intensive Management
ISR Initial Study Report
mg/L milligrams per liter
NETC Nushagak Electric & Telephone Cooperative, Inc.
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USGS U.S. Geological Survey
USR Updated Study Report
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
The water resources study plan approved by FERC consists of three major study areas: 1) water
quality; 2) flow duration curves; and 3) ice processes. The water quality study involves the field
collection and monitoring of dissolved oxygen (DO) data during the 2023 study season with
water temperatures being monitored during the 2023 and 2024 study seasons. Details and
background information relevant to the water quality assessment are discussed below.
The Nuyakuk River is protected by designated use criteria (C) by the Alaska Department of
Environmental Conservation (ADEC). This water use should meet specific water quality
standards to ensure the “Growth and Propagation of Fish, Shellfish, Other Aquatic Life, and
Wildlife” (ADEC 2022). As a part of the Proposed Study Plan (PSP) and Revised Study Plan
(RSP) process, baseline water quality data for DO and water temperature were requested.
Specifically, a DO study was requested by a public stakeholder, Pat Vermillion, owner of the
Royal Coachman Lodge. Water temperature monitoring was added to the study program to
assess how water temperatures at the Project site compare to historical data from the nearby
United States Geologic Survey (USGS) gaging station 1530200. Water quality results from this
study would be compared to ADEC criteria summarized in Table1-1. In addition, DO data will
be qualitatively assessed to determine if Nuyakuk Falls serves as a location replenishing DO
levels along the river corridor.
Table 1-1. ADEC criteria for water use category (C)
Parameter Criteria
Dissolved Oxygen greater than 7 mg/l
Temperature
May not exceed 20°C at any time. The following maximum
temperatures may not be exceeded, where applicable:
Migration routes 15°C
Spawning areas 13°C
Rearing areas 15°C
Egg & fry incubation 13°C
2.0 STUDY GOALS AND OBJECTIVES
The primary goals of this study are the following:
1. Collect baseline continuous (DO) data during periods of peak water temperatures (July –
August) for a minimum of 72 hours.
2. Collect baseline continuous water temperature data for a minimum of a calendar year
(January – December).
3. Determine if DO concentrations are substantially different above and below Nuyakuk
Falls.
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 2 December 2023
4. Compare the study results to DO and water temperature criteria established by the Alaska
Department of Environmental Conservation (ADEC).
3.0 STUDY AREA
The continuous monitoring of DO and water temperature included two main study locations.
Study location 1 was upstream of Nuyakuk Falls in proximity to the proposed intake structure.
Study location 2 was downstream of the Falls in an area near the proposed Project tailrace
(Figure 3-1).
4.0 METHODOLOGY
4.1 Water Temperature
As a part of its feasibility assessment in June of 2018, the Nushagak Electric & Telephone
Cooperative, Inc. (NETC or Cooperative) deployed calibrated Onset Prov2 temperature loggers
at two locations, one upstream and one downstream of Nuyakuk Falls. Field procedures, as well
as pre-deployment instrument calibration, followed techniques detailed by Ward (2011). The
thermographs were set to record temperatures at 30-minute intervals and provided a temperature
record through January of 2021, until the loggers memory was full. The thermographs were
downloaded and re-launched in June of 2022 and were last downloaded in September of 2022.
An attempt to download the thermographs on August 30, 2023 was unsuccessful due to
instrument housings being rusted shut. Another attempt to download the loggers will be made in
late September of 2023 to add to the temperature record and be included as a part of the USR due
in December of 2024. NOTE: Given the logging interval as well as available instrument
memory, data collected between September 2022 and September 2023 are not lost. These data
were not downloaded in a timely manner to be included within the Initial Study Report (ISR).
4.2 Dissolved Oxygen
Calibrated Onset U26-001 DO loggers were deployed upstream and downstream of Nuyakuk
Falls July 27 – August 1, 2023 and collected data every 30 minutes. The summer sampling
period was selected to represent the time frame when DO concentrations are typically at their
lowest, in response to water temperatures being at their warmest (Allan, 1995). Per
manufacturer suggestions, a spot check of DO levels were measured with a calibrated water
quality meter at the conclusion of the monitoring period. These check measurements served as
confirmation of calibration integrity during the deployment period and are summarized in Table
4-1.
Table 4-1. Summary of DO spot calibration checks vs, continuous loggers.
Date
Upstream
DO (mg/l)
S/N
2118686
DO Spot
Check (mg/l)
S/N 2118685
Percent
Agreement
Downstream
DO (mg/l)
S/N 2118687
DO Spot
Check (mg/l)
S/N 2118685
Percent
Agreement
8/1/2022 10.9 10.8 100.9% 10.8 10.8 100.0%
Nuyakuk River Hydroelectric Project Water ResourcesFERC No. 14873 Initial Study Report – Attachment H Nushagak Cooperative, Inc. 3 December 2023Figure 3-1. Water Quality Assessment Monitoring Locations.
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 4 December 2023
5.0 RESULTS
5.1 Dissolved Oxygen
Figure 5-1 shows the time series of continuous DO data recorded upstream and downstream of
Nuyakuk River Falls. DO concentrations at the upstream location ranged from 8.9 mg/l to 13.0
mg/l and followed a daily diurnal pattern compared to the downstream station. At the
Downstream site, DO concentrations were relatively stable ranging from 10.8 mg/l to 11.8 mg/l
during the study period. Overall, DO in the Nuyakuk River never dropped below 8.9 mg/l,
meeting ADEC criteria during the entire monitoring period.
Figure 5-1. Nuyakuk River Water Quality Data - Dissolved Oxygen
5.2 Water Temperature
Figures 5-2 and 5-3 show the time series of maximum daily water temperatures recorded at the
Project site and USGS station 15302000. From 2018 through 2020, three summers of
monitoring reveal that maximum daily temperatures briefly exceed ADEC’s 20°C criteria at the
USGS station in July and August of 2019 as well as in late July of 2020. At the Project site, the
20°C exceedance occurs only once, in early July of 2019. In 2018 and 2022 both river stations
meet the 20°C standard. The two monitoring periods also show that the 15°C criteria for
0
2
4
6
8
10
12
14
7/27/2023 7/28/2023 7/29/2023 7/30/2023 7/31/2023 8/1/2023 8/2/2023
Date
Nuyakuk River Dissolved Oxygen
Nuyakuk R-Upstream of Falls Nuyakuk R-Downstream of Falls ADEC Criteria (7 mg/l)
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 5 December 2023
migration routes/rearing areas and 13°C criteria for spawning areas/egg & fry incubation can be
exceeded from early-June through mid-September. Over the winter, temperatures drop to < 4°C
by November 1 and remain near or below 4°C through May 1. Finally, the 2022 data
summarized in Figure 5-3 reveals some interesting patterns. Water temperatures upstream of the
Falls are consistently warmer than the USGS station through mid to late-July of 2022. From
August 1, 2022 the temperature station upstream of the Falls is cooler than USGS station
15302000 through mid-September of 2022. Downstream of the Falls, water temperatures are a
bit warmer than USGS station 15302000 through mid-June of 2022, but remain cooler or equal
to USGS temperatures for the remainder of the 2022 monitoring period. The June-September of
2022 monitoring period also reveals that water temperatures are detectably cooler downstream of
the Falls in comparison to the station upstream of the Falls.
Figure 5-2. Nuyakuk River Daily Maximum Water Temperatures (July 24, 2018 – January 4, 2021) -
Project site and USGS 1530200.
-4
0
4
8
12
16
20
24
Date
NETC Temperature (°C)
USGS Temperature (°C)
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 6 December 2023
Figure 5-3. Nuyakuk River Daily Maximum Water Temperatures (June 1 – September 30, 2022) –
NETC Project site and USGS 1530200.
6.0 DISCUSSION AND FINDINGS
The > 7mg/l ADEC criteria for DO was met for the 4-day monitoring period. The diurnal pattern
of the DO hydrographs indicates that the density of aquatic plants upstream of the Falls is
enough to affect DO concentrations. During daylights hours, aquatic plants are
photosynthetically producing enough oxygen to increase DO concentrations in the water column.
Conversely, aquatic plant respiration and the consumption of DO occurs after the sunset to
detectably decrease DO concentrations. Hydraulic conditions downstream of the fFalls appear to
limit the density of aquatic plants, creating a stable intra-daily DO pattern. In fact, the time-
series of DO concentrations below the Falls bisects the DO hydrograph upstream up of the Falls,
roughly summarizing the daily average DO concentration near the proposed intake structure. As
summarized in Table 6-1, average daily DO concentrations agree within 0.5 mg/l above and
below Nuyakuk Falls for days with a complete 24-hr data collection period (July 28-July 31,
2023). Two of the dates show higher daily average DO concentrations upstream of the Falls
(July 30-31, 2023), while July 28-29, 2023 shows slightly higher daily average DO levels
downstream of the Falls. Overall, these results indicate there is adequate DO in proximity to the
proposed Project site, and that any potential diversions of water bypassing Nuyakuk Falls is not
likely to adversely impact DO concentrations.
-4
0
4
8
12
16
20
6/1 7/1 8/1 9/1 10/1
Date
NETC-U/S Temperature (°C)
NETC-D/S Temperature (°C)
USGS Temperature (°C)
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 7 December 2023
Table 6-1. Daily average DO concentrations upstream and downstream of the proposed Nuyakuk
Falls Project site.
Date U/S of Falls D/S of Falls
Dissolved Oxygen (mg/L)
7/27/2023* 11.5 11.3
7/28/2023 11.2 11.6
7/29/2023 10.8 11.3
7/30/2023 11.0 10.9
7/31/2023 11.1 10.9
8/1/2023* 9.7 10.6
*partial day of continuous data collection
Water temperatures exceeded the ADEC maximum of 20°C for 6 days between July 5 - July 11,
2019 based on available data collected from 2018-2022. Supplemental water temperature
criteria of 13°C and 15°C were also exceeded from mid to late June through early to mid-
September in 2019 and 2020. Both the 2018 and 2022 monitoring seasons were cooler and met
the 20°C criteria. The partial summer monitoring season of 2018 did not exceed the 15°C
criteria and exceeded the 13°C criteria for a total of 12 days; 8 days in early August; and 4 days
mid-September of 2018. In 2022, the June 7- September 12, 2022 monitoring period reveals 56
days exceeding 13°C and 8 days exceeding 15°C. There does appear to be a slightly cooler daily
maximum water temperatures between the monitoring sites upstream and downstream of
Nuyakuk Falls. Given the width of the Nuyakuk River (>550 ft), as well as the non-turbulent
flow between Tikchik Lake and the upstream end of the Falls, it is not surprising that there are
warmer temperatures measured in the summer during the longest periods of daylight. Once the
waters pass over Nuyakuk Falls, they become fully mixed, incorporating potentially colder water
at depth and not reaching the magnitude of daily maximum temperatures upstream of the Falls or
at the USGS station 15302000 near the Tikchik Lake outlet. Overall, these concurrent data show
that the water temperature records from USGS station 15302000 since 2013 can be incorporated
into the future flows and water temperature models being developed as part of the Project’s
aquatic resources studies.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no variances to the water quality assessment study plan.
8.0 STUDY STATUS AND SCHEDULE
The water quality assessment studies have met their minimum monitoring objectives and should
be considered complete. However, at an ARWG meeting on October 25, 2023, Lee Borden
(ADFG) requested supplemental monitoring DO in Year 2 of the study program. Specifically,
ADFG would like to know if DO levels become substantially depleted when large numbers of
Sockeye are milling at the base of Nuyakuk Falls. The Cooperative will work with ADFG to
Nuyakuk River Hydroelectric Project Water Quality Assessment
FERC No. 14873 Initial Study Report – Attachment H
Nushagak Cooperative, Inc. 8 December 2023
ensure the timing and goals of the Year 2 DO study request are met. In addition, given the
accuracy of the deployed thermographs, these units will continue to collect data through the fall
of the 2024 study season. Updated DO and temperature conditions at the Project site will be
assessed and summarized as part of the USR in December of 2024.
9.0 STUDY-SPECIFIC CONSULTATION
Additional agency consultation was not necessary to execute the water quality assessment study
program during the 2023 study season. As described in Section 8.0, consultation with ADFG
will occur prior to the 2024 study season to ensure DO data collection efforts meet study
objectives.
10.0 REFERENCES
ADEC (Alaska Department of Environmental Conservation). 2022. 18 AAC 70 Water Quality
Standards. Amended as of November 13, 2022. Register 244, January 2023. Available
at: https://dec.alaska.gov/water/water-quality/standards/
Allan, J. David. 1995. Stream Ecology: Structure and Function of Running Waters. Chapman &
Hall, London.
Milly, P.C.D., Julio Betancourt, Malin, Falkenmark, Hirsch, Zbigniew W. Kundzewicz, DennisP.
Lettenmaier 2008. Stationarity Is Dead: Whither Water Management? Science
319(5863): 573-574. doi:10.1126/science.1151915.
Rantz, S.E., and others. 1982. Measurement and Computation of Streamflow, Volume 1:
Measurement of Stage and Discharge. U.S. Geological Survey Water Supply Paper 2175.
Ward, William J. Washington State Department of Ecology Environmental Assessment
Program, 2011. Standard Operating Procedures for Continuous Temperature Monitoring
of Fresh Water Rivers and Streams. Version 2.0. Author: William J. Ward, Reviewers:
Dan Sherratt and Dave Hallock. Approved 10/26/2011, Recertified: 3/25/2015.
INITIAL STUDY REPORT
ATTACHMENT I: FLOW DURATION CURVE CHANGE ANALYSIS
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 1
4.0 METHODOLOGY ............................................................................................................. 3
5.0 RESULTS........................................................................................................................... 4
6.0 DISCUSSION AND FINDINGS........................................................................................ 6
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 7
8.0 STUDY STATUS AND SCHEDULE................................................................................ 7
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 8
10.0 REFERENCES ................................................................................................................... 8
LIST OF FIGURES
Figure 3-1. Stream Gage Location at the Proposed Project Site......................................................2
Figure 4-1. Schematic and example of a typical data logger and staff gage installation. ................3
Figure 5-4. X-Y Scatter plot of stage-discharge relationship at the Nuyakuk River Project
site. ...........................................................................................................................5
Figure 5-5. Nuyakuk River daily mean discharge at the NETC Project Site and USGS
Station 1530200. ......................................................................................................5
Figure 5-6. Correlation of the discharges from the NETC Project site stream gage vs USGS
stream gage 15302000. ............................................................................................6
Figure 6-1. Accretion calculations between Project site and USGS gaging stations – June 7,
2022 to August 27, 2023. .........................................................................................7
LIST OF TABLES
Table 5-1. Discharge summary table at the Nuyakuk River Project site. ........................................4
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. ii December 2023
ACRONYMS AND ABBREVIATIONS
ADCP acoustic doppler current profiler
ADF&G Alaska Department of Fish and Game
ARWG Aquatics Resources Working Group
cfs cubic feet per second
Commission Federal Energy Regulatory Commission
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ft foot
NMFS National Marine Fisheries Service
Project Nuyakuk River Hydroelectric Project (P-14873)
PSP Proposed Study Plan
RSP Revised Study Plan
USGS U.S. Geological Survey
USR Updated Study Report
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
The water resources study plan approved by FERC consists of three major study areas: 1) water
quality; 2) flow duration curves; and 3) ice processes. Temporal changes to the flow duration
curve on the Nuyakuk River will be assessed by a combination of statistical analysis combined
with the establishment of site-specific stream gage installed at the Project site. Details and
background information relevant to the flow duration curve change analysis are discussed below.
On February 4, 2020, The National Marine Fisheries Service (NMFS) filed with FERC their
Comments on the Pre-Application Document and Study Requests for the Nuyakuk River
Hydroelectric Project (P-14873). Specifically, the filing included Attachment 2: National
Marine Fisheries Service’s Study Requests for the Nuyakuk Project (FERC No. P-14873) which
detailed seven study requests. The flow duration curve change analysis (Study 4) was included
as part of the PSP and RSP filings. Study plan details, results, progress, and schedules are
provided in Section 2.0 through 10.0 of this report.
2.0 STUDY GOALS AND OBJECTIVES
The goal of the study is to evaluate changes in the flow duration curve for the Nuyakuk River
that have happened during the United States Geological Survey (USGS) 15302000 gage record
which spans 70 years (1953- 2023). There are a small number of years during this period with
no data and many years where the winter flow record is estimated. This study does not analyze
climate projections or future flows. The objectives of this study are:
a. Determine if flow pattern observable for the USGS Nuyakuk River gage record
exhibit stationarity as hydrologist assumed for decades, or if there is a statistically
significant trend (Milly 2008) consistent with other gage records in Northern climates
where a change analysis has been completed.
b. Use the appropriate data to inform the development of climate resilient
license articles. This is a statistical study using peer reviewed existing USGS flow
data.
3.0 STUDY AREA
Although the flow duration curve assessment is primarily a desktop exercise, a Project site
stream gage was installed just downstream of the proposed Project intake structure near the top
of the Falls on the right bank, looking downstream (Figure 3-1). A streamflow record from the
Project site was requested by ADF&G so that the assessment of flow duration curves at the
proposed Project location would be based on accurate flow volumes correlated to USGS gaging
station 1530200.
Nuyakuk River Hydroelectric Project Flow Duration Curve Change AnalysisFERC No. 14873 Initial Study Report – Attachment I Nushagak Cooperative, Inc. 2 December 2023 Figure 3-1. Stream Gage Location at the Proposed Project Site.
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 3 December 2023
4.0 METHODOLOGY
Following USGS guidelines, the Nuyakuk River stream gage consists of a staff gage and Onset
U20-001-04 continuous water level loggers, each anchored individually to the stream bank and
near the shoreline to avoid debris and damage during high flow conditions. The data loggers are
a pressure transducer system with an accuracy of +/-0.02 feet or +/-0.15% full scale (0.0 to 13.0
feet). The data logger accurately records pressure, which is related to the water surface elevation
at the staff gage. Data loggers record the following parameters at 30-minute intervals:
Date and time
Temperature (°C)
Pressure/Water level (feet)
The staff gage is 6.6 feet long and mounted vertically in the stream channel to provide reference
water levels to the nearest hundredth of a foot for the full range of flow conditions. The data
loggers are housed in a shoreline enclosure consisting of 2-inch galvanized pipe located within
the wetted channel. Figure 4-1 provides a schematic and example of a typical data logger and
staff gage installation.
Figure 4-1. Schematic and example of a typical data logger and staff gage installation.
The stream gage was installed on June 7, 2022 with the development of the stage-discharge
relationship commencing in May of 2023. During each gage calibration and servicing effort,
discharge data are collected to develop and maintain a stage-discharge rating relationship at the
proposed Project site. Discharge measurements follow field procedures laid out in Rantz et al
(1982) and utilized an acoustic doppler current profiler (ADCP). At each maintenance and
discharge calibration event, the following occurs:
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 4 December 2023
Comparison of electronic stage levels to reference staff gage
ADCP Discharge measurement
Downloading of electronic stage record
During the low-flow winter period in 2022-2023, site inspections were not conducted due to
access limitations. Inspection of the winter stage data revealed the stream gage was dewatered
due to low flow conditions or intermittently frozen and did not provide an accurate stage record
from November 20, 2022 to May 15, 2023. For the winter of 2023-2024, stage recording
instrumentation will be lowered into the water column to increase the probability that stage data
can be accurately logged and compared to winter data from USGS gage 1530200.
5.0 RESULTS
The statistical assessment of stationarity and generation of updated flow duration curves has not
been completed. These results will be provided as part of the Updated Study Report (USR) in
December of 2024. However, as requested by ADF&G, data from the installation of a stream
gage at the Project site is provided below.
A total of seven discharge measurements were taken from May to August of 2023 to assess and
validate the stage-discharge relationship at Nuyakuk River Project site and provide 116 and 153
days of mean daily flow data in the 2022 and 2023 water years, respectively (Table 5-1, Figure
5-4, and Figure 5-5). These concurrent data have provided an excellent correlation to USGS
gaging station 15302000 during periods of ice-free operation (Figure 5-5). Over the winter of
2022-2023, the NETC stream gage was dewatered or frozen and did not provide accurate stage
data from November 20, 2022 through May 15, 2023. Therefore, Project site gaging results from
the winter timeframe cannot be assessed in this report. Overall, accretion (i.e., flow increases)
from the USGS station downstream to the Project ranged from 97.1 cfs to 1650 cfs between the
two gaging stations, with an average accretion of 509 cfs.
Table 5-1. Discharge summary table at the Nuyakuk River Project site.
Meas.
No. Date Stage (ft)
Measured
Discharge
(cfs)
Rated
Discharge
(cfs)
Percent Difference
1 5/12/2023 0.50 2893 2882 0.4%
2 5/16/2023 1.04 4921 4997 -1.5%
3 5/19/2023 1.40 6510 6480 0.5%
4 5/21/2023 1.62 7476 7410 0.9%
5 6/21/2023 3.98 18124 18160 -0.2%
6 7/3/2023 4.19 19041 19169 -0.7%
7 8/24/2023 1.65 7537 7538 0.0%
Rating 1: Flow = 3338.63*(Stage + 0.38)^1.1502 (based on meas. No. 1-5)
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 5 December 2023
Figure 5-1. X-Y Scatter plot of stage-discharge relationship at the Nuyakuk River Project site.
Figure 5-2. Nuyakuk River daily mean discharge at the NETC Project Site and USGS Station
1530200.
0.1
1.0
10.0
1000 10000 100000
Discharge (cfs)
Nuyakuk River Stage-Q
Rating Qs
Q Check Meas
0
5,000
10,000
15,000
20,000
25,000
Date
NETC Discharge(cfs)
USGS Discharge (cfs)
ice-affected data; NETC gage offline
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 6 December 2023
Figure 5-3. Correlation of the discharges from the NETC Project site stream gage vs USGS stream
gage 15302000.
6.0 DISCUSSION AND FINDINGS
The installation of a stream gage at the Project site in June of 2022 was successful, providing an
excellent correlation to the USGS gaging station 15302000 during periods of ice-free operation
(R2 of 0.9969). Accretion (i.e., flow increases) from the USGS station downstream to the
Project ranged from 97.1 cfs to 1650 cfs with an average of 509 cfs over the June 2022-August
2023 monitoring period (Figure 6-1). There does appear to be a trend of decreasing accretion
flows between the two gaging sites starting in late October and early November. However,
given that the NETC gage was near its operational limits during that October-November
timeframe, the accuracy of these calculations cannot be validated. As described in Section 4.2,
the stream gage depth was lowered on September 26, 2023 so that a winter record can be
developed in 2023-2024 as well as an assessment of accretion during the winter timeframe.
Overall, the NETC stream gage will serve to create a more accurate flow duration curve
assessment at the proposed point of diversion.
y = 1.8545x0.939
R² = 0.9969
0
5000
10000
15000
20000
25000
30000
0 5000 10000 15000 20000 25000 30000
USGS Daily Mean Discharge (cfs)
NETC-USGS Daily Mean Discharge Correlation
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 7 December 2023
Figure 6-1. Accretion calculations between Project site and USGS gaging stations – June 7, 2022
to August 27, 2023.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no variances to the flow duration curve assessment study plan. A stream gage at the
Project location will be utilized for site-specific hydrology data as opposed to a synthetic
hydrograph developed from watershed area proportioning. Prior to the 2023-2024 winter study
season, the stream gage instrumentation was adjusted so that accurate winter stage data has a
higher probability of being collected.
8.0 STUDY STATUS AND SCHEDULE
The overarching goal of developing site-specific hydrology at the Project by correlating
discharges with USGS gage 15302000 has been completed. However, efforts to collect stage
data over the winter of 2023-2024 will continue to determine if winter correlations to USGS
gage 1530200 differ from those developed during periods of ice-free operation. Updated
discharge and accretion conditions at the Project site will be assessed and summarized as part of
the USR in December of 2024.
-1000
-500
0
500
1000
1500
2000
6/1 7/1 8/1 9/1 10/1 11/1 12/1 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/1
Date
Project Site Accretion (cfs)
November 2022: blue shaded area represents accretion calculations based NETC gage near opertional limits
July-August 2023: blue shaded area represents accretion calculations based on preliminary and estimated USGS discharge data
Nuyakuk River Hydroelectric Project Flow Duration Curve Change Analysis
FERC No. 14873 Initial Study Report – Attachment I
Nushagak Cooperative, Inc. 8 December 2023
9.0 STUDY-SPECIFIC CONSULTATION
Additional agency consultation was not necessary to execute the site-specific hydrology phase of
the flow duration curve change assessment study program during the 2023 study season. Agency
consultation is likely to occur in 2024 to ensure the flow duration curve analysis is presented in
the time periods satisfactory to NMFS and other Aquatics Resources Working Group (ARWG)
members.
10.0 REFERENCES
Milly, P.C.D., Julio Betancourt, Malin, Falkenmark, Hirsch, Zbigniew W. Kundzewicz, DennisP.
Lettenmaier 2008. Stationarity Is Dead: Whither Water Management? Science
319(5863): 573-574. doi:10.1126/science.1151915.
Rantz, S.E., and others. 1982. Measurement and Computation of Streamflow, Volume 1:
Measurement of Stage and Discharge. U.S. Geological Survey Water Supply Paper 2175.
INITIAL STUDY REPORT
ATTACHMENT J: ICE PROCESSES ASSESSMENT
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 INTRODUCTION.............................................................................................................. 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 1
4.0 METHODOLOGY ............................................................................................................. 3
5.0 RESULTS........................................................................................................................... 3
6.0 DISCUSSION AND FINDINGS........................................................................................ 4
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 4
8.0 STUDY STATUS AND SCHEDULE................................................................................ 5
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 5
LIST OF FIGURES
Figure 3-1. Ice Processes Study Area. .............................................................................................2
Figure 5-1. Screen capture of satellite imagery of Nuyakuk River Falls on April 18, 2023. ..........4
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. iii December 2023
ACRONYMS AND ABBREVIATIONS
API Application Programming Interface
ARWG Aquatics Resources Working Group
Commission Federal Energy Regulatory Commission
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ISR Initial Study Report
NMFS National Marine Fisheries Service
Project Nuyakuk River Hydroelectric Project (P-14873)
PSP Proposed Study Plan
RSP Revised Study Plan
USR Updated Study Report
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
The water resources study plan approved by FERC consists of three major study areas: 1) water
quality; 2) flow duration curves; and 3) ice processes. Ice processes will be assessed with a
literature search as well as on-site and satellite images over the winter. Details and background
information relevant to the ice processes assessment are discussed below.
On February 4, 2020, The National Marine Fisheries Service (NMFS) filed with FERC their
Comments on the Pre-Application Document and Study Requests for the Nuyakuk River
Hydroelectric Project (P-14873). Specifically, the filing included Attachment 2: National
Marine Fisheries Service’s Study Requests for the Nuyakuk Project (FERC No. P-14873) which
detailed seven study requests. The ice processes assessment (Study 6) was included as part of
the Proposed Study Plan (PSP) and Revised Study Plan (RSP) filings. Study plan details, results,
progress, and schedules are provided in Section 2.0 through 9.0 of this report.
2.0 STUDY GOALS AND OBJECTIVES
The primary goal of this study is to utilize satellite imagery, data supplemented by site-specific
photos and/or video, and literature searches to gain a better understanding of both existing ice
formation processes and the potential for localized modifications to these processes as a result of
Project operations. Specifically, the objectives of this study are:
a. Obtain a clearer understanding of the amount of icing that has happened above
Nuyakuk Falls during the last 20 years from satellite or overflight images.
b. Complete a literature search of other facilities and determine which climatic
conditions (temperatures, relative humidity, wind) cause the most challenges.
Compare this to the Future Flows and Temperature study results to determine
how frequently icing problems are likely to develop.
c. Obtain imagery (videos or photos) from remote cameras during two winters
to better un understand frazil ice production processes and spring breakup.
Determine if lake ice during spring breakup eddies out in front of the
proposed intake.
3.0 STUDY AREA
The ice processes assessment study included one primary study location upstream of Nuyakuk
Falls. The study area is represented as Zone 1 in Figure 3-1, starting at the intake structure and
extending upstream approximately 1,500 feet.
Nuyakuk River Hydroelectric Project Ice Processes AssessmentFERC No. 14873 Initial Study Report – Attachment J Nushagak Cooperative, Inc. 2 December 2023 Figure 3-1. Ice Processes Study Area.
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. 3 December 2023
4.0 METHODOLOGY
Desktop exercises relating to the ice processes assessment are described in the RSP with results
and findings to be provided in the USR. In June of 2022 cameras were mounted at 2 locations to
view the intake area of the proposed Project location. Each camera was programmed to log
photos three times per day at 10 am, 12pm, and 3pm. The goal was to capture daily, site-specific
imagery over the winter of 2022-2023. The cameras were retrieved and downloaded at the
beginning of the study season in May of 2023. No images were saved on either camera. It is not
clear if the lack of site imagery was due to a programming error, failed memory cards, or
deploying cameras unable to operate in extremely cold conditions. An alternative method to
collect site-specific imagery will be discussed at upcoming Aquatics Resources Working Group
(ARWG) meetings and finalized at the Initial Study Report (ISR) meeting in mid-December of
2023. Alternative measures will be employed based on imagery provided by remote cameras
scheduled to be downloaded shortly after the December ISR meeting.
5.0 RESULTS
As summarized in Section 4.0, site specific imagery is not available for the winter 2022-2023
study season. An example of satellite imagery from the application programming interface (API)
suggested by NMFS (https://www.sentinel-hub.com/) is provided in Figure 5-1. This will allow
agencies the chance to review the resolution of available satellite imagery and define the scope
of its usage as a part of the ice processes assessment. As summarized in Section 4.0, alternative
methods to collect site-specific imagery will be employed during the winter of 2023/2024 based
on results of camera downloads in December of 2023.
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. 4 December 2023
Figure 5-1. Screen capture of satellite imagery of Nuyakuk River Falls on April 18, 2023.
6.0 DISCUSSION AND FINDINGS
Study results will be summarized and discussed in December of 2024 when the USR is due to be
filed with FERC following Year 2 of the Study Program. The status of the Ice Processes study
program will be presented and collaboratively discussed with stakeholders during the ISR
meeting in December of 2023.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no variances to the ice processes assessment study plan. However, given the failure
of the camera system in 2022-2023, alternatives for the collection of site-specific imagery will be
discussed at upcoming ARWG meetings in October and November of 2023. Implementation of
collaboratively agreed upon alternative methods will be implemented following the results of
camera downloads in early December of 2023.
Nuyakuk River Hydroelectric Project Ice Processes Assessment
FERC No. 14873 Initial Study Report – Attachment J
Nushagak Cooperative, Inc. 5 December 2023
8.0 STUDY STATUS AND SCHEDULE
Field data collection in the winter of 2022-2023 proved unsuccessful and needs to be continued
over the winter of 2023-2024. Desktop assessments of satellite imagery, literature searches and
discussions with operators of the Tazimina Falls Project (P-11316) will occur during the second
study season and be summarized in the USR.
9.0 STUDY-SPECIFIC CONSULTATION
Additional agency consultation did not occur for the ice processes assessment study program
during the 2023 study season. Given the lack of site-specific results in 2022-2023, ARWG
consultation, specifically with NMFS needs to occur so that the objectives of this study program
can be met over the 2023-2024 study season.
INITIAL STUDY REPORT
ATTACHMENT K: BOTANICAL AND WETLANDS SURVEY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
3.1 Project Facility Study Area..................................................................................... 2
3.2 Transmission Line Study Area................................................................................ 3
4.0 METHODOLOGY ............................................................................................................. 4
4.1 General Vegetation Type/Wetland Mapping.......................................................... 4
4.1.1 Available Data Analysis ............................................................................. 4
4.1.2 Field Work Comparison.............................................................................. 9
4.2 Field Vegetation Surveys/Wetland Delineation...................................................... 9
4.2.1 Vegetation Survey....................................................................................... 9
4.2.2 Wetland Delineation................................................................................... 9
5.0 RESULTS ......................................................................................................................... 10
5.1 General Vegetation Type/Wetland Mapping ........................................................ 10
5.1.1 Project Facility Study Area Mapping ....................................................... 10
5.1.2 Overall Mapping of Project Facility and Transmission Line.................... 13
5.2 Field Vegetation Surveys/Wetland Delineation.................................................... 17
5.2.1 Vegetation Classification .......................................................................... 17
5.2.2 Wetland Classification .............................................................................. 20
6.0 DISCUSSION AND FINDINGS...................................................................................... 27
6.1 General Vegetation Type/Wetland Mapping ........................................................ 27
6.2 Field Vegetation Surveys/Wetland Delineation.................................................... 27
6.2.1 Vegetation ................................................................................................. 27
6.2.2 Wetlands ................................................................................................... 28
6.3 Overview ............................................................................................................... 28
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 29
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 29
8.1 General Vegetation Type/Wetland Mapping ........................................................ 29
8.2 Rare Plants ............................................................................................................ 29
8.2.1 Schedule.................................................................................................... 29
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. iii December 2023
8.3 Wetland Functional Assessment ........................................................................... 29
9.0 STUDY-SPECIFIC CONSULTATION........................................................................... 30
10.0 REFERENCES ................................................................................................................. 31
LIST OF FIGURES
Figure 3-1. Proposed Project facility study area..............................................................................2
Figure 3-2. Schematic map of proposed transmission lines (red) and existing transmission
lines (orange). ..........................................................................................................3
Figure 4-1. Alaska Wetlands Map depicting eight wetland/deepwater classes and one
upland class (Flagstad et al. 2018). ..........................................................................5
Figure 4-2. Observed foliar cover compared to predicted foliar cover for Wetland Sedges
from the merged test partitions of 10-fold cross-validation, wherein each
observation was predicted exactly once (Nawrocki, et. al 2013). ...........................8
Figure 5-1. Contour mapping of the Project facility study area. ...................................................11
Figure 5-2. Predicted Wetland Sedge areas and hydrology data within the Project facility
study area. ..............................................................................................................12
Figure 5-3. Estimated hydric soils within the transmission line study area...................................15
Figure 5-4. Wetland Sedge foliar coverage and hydrology data within the transmission line
study area ...............................................................................................................16
Figure 5-5. Project facility site vegetation types (A) Closed Mixed Forest [IC1] and
adjacent Closed Low Shrub [IIC1] (B) Mixed Woodland [IC3]...........................17
Figure 5-6. Primula spp. (A) Close-up of the Primula spp. (B) Riverine plant community
where the Primula spp. was found during the vegetation study from August
8-15, 2023..............................................................................................................18
Figure 5-7. Map of Primula spp. found on the north side of the Project facility outfall. ..............19
Figure 5-8. Distribution of P. tschuktschorum (Nawrocki et al. 2013)..........................................19
Figure 5-9. Map of Project facility study area wetlands and related sample data points ..............22
Figure 5-10. PEM wetlands found southeast of the Project facility study area at sample
point PF-13.............................................................................................................24
Figure 5-11. Map of Project facility study area wetlands and the proposed Project facilities. .....26
LIST OF TABLES
Table 4-1. Widespread species used by Nawrocki et al. (2021) for mapping based on
prevalence in combined vegetation plot data for North American Beringia
(Nawrocki et al. 2021). ............................................................................................6
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. iv December 2023
Table 4-2. Accuracy of Wetland Sedges by region and subregion at the site scale
(Nawrocki et al. 2013). ............................................................................................8
Table 5-1. Rare plant survey results. The results indicate a Primula spp., potentially the
Primula tschuktschorum........................................................................................20
Table 5-2. Delineated wetland types and area. ..............................................................................23
Table 8-1. Rare plant identification schedule.1 ..............................................................................29
Table 9-1. Vegetation and wetland delineation agency consultation history. ...............................30
APPENDICES
Appendix K-1 Project Area Vegetation Mapping
Appendix K-2 Project Facility Preliminary Wetland Delineation Report
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. v December 2023
ACRONYMS AND ABBREVIATIONS
ACCS Alaska Center for Conservation Science
ADNR Alaska Department of Natural Resources
AKEPIC Alaska Exotic Plants Information Clearinghouse
AKNHP Alaska Natural Heritage Program
AKVEG Alaska Vegetation Plots Database
BLM Bureau of Land Management
Commission Federal Energy Regulatory Commission
DNA Deoxyribonucleic Acid
FAC facultative
FACW facultative wetland
OBL obligate
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
ft foot
GIS Geographic Information System
GPS Global Positioning System
IFSAR Interferometric Synthetic Aperture Radar
ISR Initial Study Report
kV kilovolt
LIDAR Light Detection and Ranging
NWI National Wetlands Inventory
PAD Pre-Application Document
PEM Palustrine Emergent
PEM1E Seasonally Flooded/Saturated Palustrine Emergent
PEM1B Saturated Persistent Palustrine Emergent
Project Nuyakuk River Hydroelectric Project (P-14873)
PCN Pre-Construction Notification
PSS Palustrine Scrub-Shrub
PSS1B Saturated and Intermittently Flooded
PSS1J Intermittently Flooded Broad-Leaved Deciduous Palustrine Scrub-
Shrub
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. vi December 2023
PUB Palustrine Unconsolidated Bottom
PUB2H Permanently Flooded Sand Palustrine Unconsolidated Bottom
RSP Revised Study Plan
ssp. Species
UAA University of Alaska Anchorage
USACE U.S. Army Corps of Engineers
USFWS U.S. Fish and Wildlife Service
USGS U.S. Geological Survey
USR Updated Study Report
WOTUS Waters of the United States
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
MLP & Associates (MLP&A) was contracted by McMillen for 2023-2024 Nushagak Electric
and Telephone Cooperative (Cooperative) Nuyakuk River Hydroelectric Project (Project)
Revised Study Plan (RSP) support. The Cooperative is currently evaluating the potential for
constructing a hydroelectric facility on the Nuyakuk River to supply nearby villages with
electricity. As part of the Federal Energy Regulatory Commission (FERC) licensing process, a
suite of terrestrial studies has been included in the overall feasibility assessment. MLP&A
assisted the Cooperative with the proposed terrestrial resource studies including the botanical and
wetland survey described in this report.
As part of the licensing process and potential impact assessment for the proposed Project, the
Cooperative committed to conducting a study to gather baseline botanical and wetland data,
including surveying vegetation types, wetlands, Bureau of Land Management (BLM) Special
Status plant species, and non-native plant species in the proposed Project facility. The study
consisted of both desktop and field-based data collection methods.
2.0 STUDY GOALS AND OBJECTIVES
As established in the RSP (Section 4.3.1), the overall goals of the study were to classify and
prepare maps of the existing botanical and wetland areas in the proposed Project boundary.
Specific goals of this study were to:
•Refine existing vegetation and wetland mapping available for the Project vicinity, both
through desktop analysis and field data collection, in order to be able to assess Project
impacts on these resources;
•Identify any BLM Alaska Special Status plant species that may occur in the area where
Project impacts to terrestrial resources may occur;
• Locate any populations of non-native vegetation species in the Project facilities vicinity,
so that appropriate management practices can be developed, if needed; and
• Identify and classify wetlands in the proposed Project boundary and other Waters of the
United States (WOTUS) in accordance with U.S. Army Corps of Engineers (USACE)
practices to define areas subject to federal regulation and policies.
Wetlands and WOTUS are subject to USACE regulations and policies, but some submerged
lands and uplands within Wood-Tikchik State Park are owned by the State of Alaska (ADNR
2002) and also subject to state land use authorization.
Classification and mapping of the vegetation and wetland habitat will support further Project
planning, applications for appropriate authorizations, and avoidance or mitigation of potential
negative Project impacts.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 2 December 2023
3.0 STUDY AREA
The proposed FERC Project boundary area includes 1) a Project facility area that would
encompass the power generation facility, onsite housing, Project runway, and other operational
components as well as 2) a transmission line route connecting from the operational facility to
several existing transmission lines and new village endpoints. The proposed Project boundary
includes land owned by the State of Alaska, Alaska Native villages or Tribal corporations, BLM,
and private or municipal entities.
Soils, vegetation, and hydrology within the study area are mostly natural and undisturbed. It is
situated within the Bristol Bay-Nushagak Lowlands, which is characterized as rolling lowlands
formed from morainal deposits (Gallant et al. 1995).
3.1 Project Facility Study Area
The Project facility study area is located approximately 60 miles northwest of Dillingham,
Alaska, adjacent to the Nuyakuk River. It comprises 97.59 acres surrounding those areas that
would be directly altered or disturbed (short and long-term) by development and operation of the
proposed Project operational facilities (Figure 3-1). The facilities would be entirely located on
land owned by the State of Alaska, within Wood-Tikchik State Park.
Figure 3-1. Proposed Project facility study area.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 3 December 2023
The Wood-Tikchik State Park Management Plan describes the coniferous and mixed coniferous-
deciduous forests, willow-alder thickets, tundra, and alpine meadows that characterize the
vegetation within the park. This vegetation provides wildlife habitat and is sometimes utilized for
firewood collection or subsistence harvesting.
3.2 Transmission Line Study Area
The proposed Project transmission line right-of-way comprises of approximately 1,227 acres,
which includes a 75-foot-wide swath along the full line corridor (Figure 3-2). The present design
concept consists of 135 miles of new transmission line utilizing 34.5 kilovolt (kV) insulated steel
tower and steel pole construction (or a combination of the two) distributed over the transmission
corridor. To avoid unnecessary impacts to wetlands and WOTUS, the transmission line will be
routed, where possible, along uplands, higher terrain, and ridgelines. Areas adjacent to the
proposed transmission line routes, vegetation and potential botanical areas and wetlands are
mapped.
Figure 3-2. Schematic map of proposed transmission lines (red) and existing transmission lines
(orange).
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 4 December 2023
4.0 METHODOLOGY
4.1 General Vegetation Type/Wetland Mapping
High-resolution, site-specific botanical and wetlands data currently do not exist for the proposed
Project location. General descriptions of types of terrestrial vegetation and wetlands were
provided in the Pre-Application Document (PAD) (Section 4.5.2). Detailed surveys of non-native
vegetation species or Special Status plant species have not been conducted in the proposed
Project location to date. Site-specific data are necessary in order to assess any potential impacts
to these resources.
A desktop analysis of the best available aerial imagery and existing wetland and vegetation
geographic information system (GIS) datasets from sources including federal, state, and local
entities was performed to prepare preliminary vegetation type and wetland mapping. The
mapping information was then used to guide field data collection efforts, including identifying
potential wetland locations and areas for sensitive and non-native plant surveys. A final series of
maps were produced which display vegetation type, specific Project components, and potential
impact areas.
Deliverables from this study component include GIS layers and maps of anticipated wetland
plants and hydric soils located in the proposed FERC Project boundary.
4.1.1 Available Data Analysis
The U.S. Fish & Wildlife Service (USFWS) National Wetland Inventory (NWI) does not include
mapped wetlands data for the Project boundary area. However, this dataset was consulted where
present in nearby areas to compare and verify assumptions made when utilizing other available
datasets in the Project area.
A recent study mapped the statewide distribution of wetland, deepwater, and upland habitats
(Flagstad et al. 2018). The result was a map of wetlands in accordance with the national wetland
classification system at medium-scale resolution for Alaska (Figure 4-1; Flagstad et al. 2018).
The data from the map were not recommended for use for this Project because the maps did not
provide enough detail for the Project area.1
As an alternative to the Flagstad et al. (2018) study, vegetation data from the Alaska Center for
Conservation Science (ACCS) (in consultation with and provided by Timm Nawrocki) were
recommended. A description of this consultation is provided in Section 4.1.1.1. These data are
provided as georeferenced single band raster images with a 10 x 10-meter resolution. The rasters
were color-coded using a gradient color ramp to signify the percent foliar cover.
To approximate hydrology, hydrography data were downloaded from USGS National
Hydrographic Dataset (USGS 2023).
1 Maria Lewis (MLPA) personal communication with Lindsey Flagstad (ACCS), 9/11/2023.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 5 December 2023
Contours using Light Detection and Ranging (LIDAR) and Interferometric Synthetic Aperture
Radar (IFSAR) were also mapped to better understand the terrain within the Project facility study
area (Figure 5-1). Contours showing sufficient detail can act as a guide to hydrology and likely
locations for wetlands. However, detailed contours were not available throughout the entire
Project boundary area.
Hydric soil data were then examined; however, they did not provide adequate detail to locate
potential wetlands (USDA, NRCS 2023).
Figure 4-1. Alaska Wetlands Map depicting eight wetland/deepwater classes and one upland class
(Flagstad et al. 2018).
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 6 December 2023
4.1.1.1 Consultation with Alaska Center for Conservation Science
Timm Nawrocki, M.S. (a terrestrial ecologist with ACCS who specializes in spatial analysis of
terrestrial vegetation, soils, and wildlife; remote sensing; and plant identification) recommended
mapping Wetland Sedges and Sphagnum (moss) as a way to estimate wetlands in the overall
Project area. This recommendation was based on the results of analyses included in “Continuous
Foliar Cover of Plant Species and Aggregates in North American Beringia Map User Guide and
Accuracy Assessment” (Nawrocki et al. 2021).
As part of the Nawrocki et al. (2021) analyses, quantitative continuous foliar cover maps were
developed for 15 plant species (Table 4-1) to improve representation of vegetation composition
patterns relevant to plant communities and wildlife habitats in North American Beringia. To map
patterns of foliar cover, observations of vegetation foliar cover were statistically associated with
environmental, multi-season spectral, and surface texture covariates using hierarchical statistical
learning models (Nawrocki et al. 2021).
Of the 15 species mapped, Wetland Sedges and Sphagnum mosses were selected for this study as
both have the potential to serve as wetland indicators 2. Nawrocki et al. (2021) found that
Wetland Sedges perform as a wetland indicator due to their response to soil-ice dynamics (e.g.,
troughs, low-centered polygons, drained thaw lakes) while Sphagnum mosses play a role in soil
thermal regulation. In western Alaska, these data have shown to provide 86 percent accuracy in
predicting Wetland Sedge foliar cover. (Nawrocki et al. 2013).
Table 4-1. Widespread species used by Nawrocki et al. (2021) for mapping based on prevalence in
combined vegetation plot data for North American Beringia (Nawrocki et al. 2021).
Species or
Aggregate1 Common Name Lifeform Rationale
Picea glauca – _×
lutzii Spruce species Coniferous Tree
forest structure, fuels for fire,
hydrography, wildlife physical
habitat
Picea mariana Black spruce Coniferous Tree forest structure, fuels for fire,
wildlife physical habitat
Betula Trees Birch species Deciduous Tree
forest structure, post-fire succession,
wildlife habitat and forage
Deciduous Trees Deciduous Tree forest structure, post-fire succession,
wildlife habitat and forage
Alnus Shrubs Alder species Low-tall Shrub shrub expansion, snow retention,
hydrography
Salix Low-tall
Shrubs Willow species Low-tall Shrub
shrub expansion, snow retention,
hydrography, wildlife habitat and
forage (e.g., for moose, caribou,
muskox, and snowshoe hare)
Betula Shrubs Birch species Low-tall Shrub shrub expansion, snow retention
2 Maria Lewis (MLPA) personal communication with Timm Nawrocki (ACCS), May 25, 2023.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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Species or
Aggregate1 Common Name Lifeform Rationale
Rhododendron
Shrubs
Labrador tea
species Low-tall Shrub
associational herbivore resistance,
ethnobotanical uses, post-fire
succession
Vaccinium
uliginosum Bog bilberry Low-Dwarf
Shrub
subsistence, wildlife habitat and
forage
Dryas Shrubs Aven species Dwarf Shrub alpine and Arctic plant communities
Vaccinium vitis-
idaea Lingonberry Dwarf Shrub
subsistence, wildlife habitat and
forage (e.g., for voles, lemmings,
sparrows, bears, and caribou in
winter)
Empetrum nigrum Crowberry Dwarf Shrub
subsistence, wildlife habitat and
forage, Alaska Peninsula and
Yukon-Kuskokwim Delta plant
communities
Eriophorum
vaginatum
Tussock
cottongrass Graminoid
tussock formation, soil ice dynamics
(e.g., high- and flat-centered
polygons)
Wetland Sedges Sedge species Graminoid
wetland indicator, soil-ice dynamics
(e.g., troughs, low-centered
polygons, drained thaw lakes),
wildlife habitat and forage
Sphagnum Moss species Bryophyte
wetland indicator, carbon
sequestration, soil thermal
regulation
1Some are aggregate species
To determine if the Wetland Sedges could be used to estimate wetlands within the Project area, it
was necessary to ascertain how accurate the predicted foliar cover was to observed cover.
According to an accuracy assessment (Table 4-2) the observed sedge foliar cover to predicted
cover is relatively high (Nawrocki et al. 2021). Accuracy of the observed sedge foliar cover to
predicted foliar cover is highest in Western Alaska at 86 percent.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 8 December 2023
Figure 4-2. Observed foliar cover compared to predicted foliar cover for Wetland Sedges from the
merged test partitions of 10-fold cross-validation, wherein each observation was predicted
exactly once (Nawrocki, et. al 2013).
Table 4-2. Accuracy of Wetland Sedges by region and subregion at the site scale (Nawrocki et al.
2013).
Subregion Continuous Foliar Cover Performance Cover
R2 MAE RMSE AUC % AA Mean Median
All 0.45 7.1 14.9 0.91 83 25.6 17.7
Northern 0.49 7.6 14.9 0.89 81 24.5 17.0
Western 0.39 6.7 15.3 0.92 86 29.1 20.0
Interior 0.4 6.3 14.0 0.89 83 22.6 14.7
4.1.1.2 GIS Analysis and Mapping
A series of maps were prepared using the data described above to assess impacts from proposed
Project elements and for use in planning final Project infrastructure placement. Those maps
include:
In the Project facility study area:
o A contour map (Figure 5-1);
o A map of Wetland Sedge data (UAA 2023) with hydrology data (USGS 2023)
(Figure 5-2);
o Delineated wetlands (Figure 5-9); and
o Delineated wetlands overlain with proposed Project facilities (Figure 5-11).
In the transmission line study area:
o A map showing likelihood of hydric soils in the region (Figure 5-3);
o Mapping of foliar coverage of white spruce, alders, Labrador tea, and crowberry
(Appendix K-1); and
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 9 December 2023
o Mapping of Wetland sedge foliar coverage and hydrology (overview Figure 5-4,
detailed maps Appendix K-1).
The vegetation data were then analyzed using GIS by using foliar cover of Wetland Sedge and
Sphagnum to predict wetland condition.
4.1.2 Field Work Comparison
Once field work was complete, adjustments were made to the maps to reflect data collection. For
example, Sphagnum was initially included as a predictor of wetland conditions in the Project
facility study area; however, Sphagnum was widely distributed throughout the entire Project
facility study area, including upland areas, proving not a good predictor of wetlands for this area.
4.2 Field Vegetation Surveys/Wetland Delineation
Field vegetation surveys and wetland delineation took place in the summer 2023, during the
season of peak flowering in Alaska. Deliverables from this study component include a written
report summarizing the results from the detailed field vegetation survey and wetland delineation
(Appendix K-2).
4.2.1 Vegetation Survey
The field vegetation survey included the following:
•Identification and mapping of any BLM Alaska Special Status plant species occurring in
the vicinity of the proposed Project facilities.
• Identification and mapping of any non-native plants appearing on the list maintained by
UAA/ACCS (UAA 2020).
A list of vegetation encountered in the Project facility study area is included in the Project’s
wetland delineation report. Classification of vegetation types based on the Alaska Vegetation
Classification system (Viereck et al. 1992) to the third classification level is described in Section
5.2.1. Further classification by species type was not attempted, as direct site investigation was
only performed at the Project facility study area. Additional mapping of dominant vegetation of
each of these classes provides guidance as to overall Project area distribution.
4.2.2 Wetland Delineation
The wetland delineation is described in detail in the wetland delineation report (Appendix K-2).
The report is noted as preliminary as a final approved determination has not been requested from
USACE and is not warranted at this time. The wetland delineation process included the
following:
•Collecting detailed information on soil conditions, hydrology, and plant community
composition in representative upland and wetland sites using guidelines from the
1987 wetland delineation manual (USACE 1987) and 2007 Alaska Regional
Supplement (USACE 2007).
•Collecting functional assessment data for each wetland.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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•Coordinates of wetland boundaries were collected by Global Positioning System (GPS)
in the field.
•Preparing a final wetland and WOTUS map for areas potentially disturbed by Project
activity using field delineation results. Maps included wetlands and other waters by
Cowardin classification (Cowardin et al. 1979, FGDC 2013), and field data collection
locations.
•Preparing a table of acres per Cowardin classification using data and maps.
•Preparing a wetland and WOTUS preliminary delineation report that included a detailed
map of areas potentially disturbed by Project activity, a general map of the entire study
area, methods and findings, a wetland functional assessment, and copies of the field data
forms.
Topography, site disturbance, vegetation, soils, and hydrologic indicators were observed and
documented. Wetland determinations were made at five sites and adjacent upland sites and
wetland boundaries were documented using a handheld GPS. Wetland boundary data from the
GPS were then mapped. Wetlands were classified according to the Cowardin Classification
system used by the U. S. Fish and Wildlife Service National Wetlands Inventory (Cowardin et al.
1979; FGDC 2013).
5.0 RESULTS
5.1 General Vegetation Type/Wetland Mapping
5.1.1 Project Facility Study Area Mapping
Estimated contours (Figure 5-1) and Wetland Sedge and Sphagnum moss cover with hydrology
(Figure 5-2) were mapped within the Project facility study area prior to field work. Once field
work was complete, maps were revised, and the Sphagnum data was removed because it was
found to be widely distributed throughout the Project facility study area.
Potential wetland areas were modeled within the Project facility study area using Wetland Sedge
data and hydrology data as potential predictors of wetlands and WOTUS. These predictions were
tested during the field study and subsequent mapping (Figure 5-2). A visible pond in the center
of the study area was confirmed during the delineation (Wetland Area 3, Figure 5-10) and two
emergent (marsh) areas (Wetland Areas 2 and 4, Figure 5-10) were identified using the sedge
data and were also verified during field work. However, the Wetland Sedge data did not predict a
scrub-shrub wetland area (Wetland Area 1, Figure 5-10) in the northeastern portion of the Project
facility study area, adjacent to the Nuyakuk River. This area may be within the Ordinary High
Water floodplain of the Nuyakuk River, but was included in the wetland study as a conservative
measure as both alternatives would likely be jurisdictional WOTUS.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 13 December 2023
5.1.2 Overall Mapping of Project Facility and Transmission Line
The Project facility and transmission line areas were initially mapped using Wetland Sedge
predicted foliar coverage data, Sphagnum data, and hydrology from the USGS National
Hydrographic Dataset (USGS 2023). However, maps were revised once field work was
completed to include Wetland Sedge data (at a level greater than 5 percent) and hydrology data.
Sphagnum data were excluded because Sphagnum was widely distributed throughout the entire
Project facility study area, including upland areas. Sphagnum data proved not to be a good
predictor of wetlands for this area. Additional maps of predicted foliar coverage of key species
observed in the Project facility area were also prepared, including white spruce (Picea glauca),
alders (Alnus spp.), Labrador tea (Rhododendron spp.), and crowberry (Empetrum nigrum).
Map sets (included in Appendix K-1) are as follows:
Predicted foliar coverage of Picea glauca (white spruce), Overview Sheet 1a and inset
Sheets 1b – 1g;
Predicted foliar coverage of Alnus spp. (alder shrubs), Overview Sheet 2a and inset
Sheets 2b – 2g;
Predicted foliar coverage of Rhododendron spp. (Labrador teas), Overview Sheet 3a and
inset Sheets 3b – 3g;
Predicted foliar coverage of Empetrum nigrum (crowberry), Overview Sheet 4a and inset
Sheets 4b – 4g;
Predicted foliar coverage of Wetland sedges and hydrology, Overview Sheet 5a and inset
Sheets 5b – 5g;
White spruce-dominated forests show the highest foliar coverage in areas that are not anticipated
to contain wetlands or wetland sedges (Sheets 1a – 1g). Dense alder shrub forests are most
common in higher elevations than the white spruce (Sheets 2a – 2g). Labrador tea (Sheets 3a –
3g) and crowberry (Sheets 4a – 4g) were mapped because of their potential correlation with
scrub-shrub wetlands, but their foliar coverage is so abundant as to make them a poor indicator.
Foliar coverage of Wetland sedges within the Project facility study area agreed well with the
wetland areas delineated during the field investigation, although not all of those wetlands were
found to be sedge dominant. Mapping in the transmission line study area shows significant
wetland sedge density immediately south of the Project facility study area for a section
continuing approximately 5 miles (Sheet 5b), an area covering approximately 3 miles along the
bend in the transmission line route to the west of Kemuk Mountain (Sheet 5b), an area covering
approximately 5 miles to the west of Koliganek (Sheet 5c), for an area covering 4 miles to the
southeast of Ekwok, for approximately 3 miles along the Muklung River west of the Muklung
Hills (Sheet 5f), and in several 0.5 – 1 mile segments of the proposed transmission route east of
Lakes Beverly and Lake Nerka (Sheet 6f).
Depending on the design of the Project facility, the route of the transmission line and the
placement of the towers/poles would determine the number of wetlands impacted by the Project.
Prevalence of hydric soil data were also mapped separately as another potential method of
estimating wetlands in the greater Project boundary area (Figure 5-3). The data provide a basic
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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Nushagak Cooperative, Inc. 14 December 2023
overview of the areas along the transmission lines that have a higher probability of hydric soils
with potential wetlands. The higher percentage of hydric soils shown likely equates to a higher
number of estimated wetlands in a particular polygon. An area directly south of the Project
facility indicates a higher probability of wetlands. Areas near Koliganek and Ekwok also show a
high probability of wetlands. However, the soils mapping was conducted at a regional scale and
is likely not a good indicator at a Project scale.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 17 December 2023
5.2 Field Vegetation Surveys/Wetland Delineation
5.2.1 Vegetation Classification
The majority of the Project facility study area is characterized by forest communities containing
trees and shrubs such as white spruce (Picea glauca), paper birch (Betula papyrifera), swamp
birch (B. nana), northern mountain-cranberry (Vaccinium vitis-idaea), and black crowberry
(Empetrum nigrum). Wetland vegetation is described in Section 5.2.2. A detailed list of the
vegetation observed in the Project facility study area is included in the Project Facility Wetland
Delineation Report (Appendix K-2).
Figure 5-5. Project facility site vegetation types (A) Closed Mixed Forest [IC1] and adjacent Closed
Low Shrub [IIC1] (B) Mixed Woodland [IC3].
Vegetation communities were classified by Viereck et al.’s Alaska Vegetation Classification
(1992) to the third classification level. Forests in the immediate vicinity of the camp facility were
typically Closed Mixed Forest [IC1] and areas of Closed Low Shrub [IIC1]. Further from camp,
often along ridges and high ground, Mixed woodland[IC3] with more abundant ericaceous heath
was common. Along the river, dense Closed Tall Shrub [IIB1] (not pictured) was common.
5.2.1.1 Rare Plants
The Alaska Natural Heritage Program (AKNHP) tracks the status of rare plant taxa in Alaska
and maintains a database with collection locality and habitat information for rare and/or endemic
vascular plants in the state. To determine which of these rare plant taxa have the potential to
occur in the Project facility study area, data were requested from AKNHP’s spatially explicit
database of rare species (AKNHP 2019b) in a broad region surrounding the proposed Project.
The query returned 32 occurrences of 13 species in the search area, and these species are listed in
Table 4-12 in the Project PAD.
A rare plant survey was conducted from August 8-15, 2023, within the Project facility study
area. One rare plant, the Primula tschuktschorum (Chukchi primrose), was potentially identified
(A)(B)
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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in the Project facility study area (Figure 5-6, Figure 5-7). The P. tschuktschorum has been found
on the Seward Peninsula, Bering Sea Islands, Ahklun Mountains, Lime Hills and the Alaska
Peninsula (Figure 5-8; Nawrocki et al. 2013). P. tschuktschorum is often mistaken for the
Primula pumila (also known as Primula eximia,Arctic primrose), which is widespread and
common in western Alaska (Carlson 2006, Nawrocki et al. 2013). The P. tschuktschorum and P.
pumila are closely related, occur in similar or the same habitat and can be difficult to
differentiate through observation only. There is also documentation of the P. tschuktschorum and
P. pumila hybridizing or cross breeding resulting in morphologically intermediate plants.3 The P.
tschuktschorum is so closely related to the P. pumila that the plants found were not accurately
identified.
A total of 12 Primula spp. plants were identified at two locations within the area (Table 5-1).
The Primula spp. is located on the north side of the Project facility outfall within a delineated
wetland (Figure 5-7).
Figure 5-6. Primula spp. (A) Close-up of the Primula spp. (B) Riverine plant community where the
Primula spp. was found during the vegetation study from August 8-15, 2023.
3 Lindsey Kendall (MLP&A) personal communication with Matthew Carlson (ACCS), August 18, 2023.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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Nushagak Cooperative, Inc. 19 December 2023
Figure 5-7. Map of Primula spp. found on the north side of the Project facility outfall.
Figure 5-8. Distribution of P. tschuktschorum (Nawrocki et al. 2013).
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
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Table 5-1. Rare plant survey results. The results indicate a Primula spp., potentially the Primula
tschuktschorum.
Common Name Scientific Name1
Number of
Occurrences in
Study Area
State
Rank2
Global
Rank3
Federal
Listings
Potential
Chukchi primrose
Potential
Primula tschuktschorum 12 S3 G2G3 BLM
Sensitive
1Identification of the Primula tschuktschorum is not confirmed.
2State Rank (Nawrocki et al 2013): S3, Rare within the state; at moderate risk of extirpation because of restricted range, narrow habitat
specificity, recent population decline, small population sizes, or a moderate number of occurrences.
3Global Rank (Nawrocki et al 2013): G2: Imperiled; at high risk of extirpation because of very restricted range, few occurrences, small
populations, steep declines, or other factors. G3: Vulnerable; at moderate risk of extinction because of restricted range, relatively few
occurrences, small populations, recent and widespread declines, or other factors. G#G#: Global status of species is best described as a range
between two ranks.
5.2.1.2 Non-Native Plants
AKEPIC (Alaska Exotic Plants Information Clearinghouse), maintained by AKNHP, provides
geospatial information for non-native plant occurrences in the State of Alaska. The database does
not contain any species occurrences near the Project facilities on the Nuyakuk River. Further
downstream, near the Nushagak River (approximately 84 miles from the Project facility site),
four occurrences of non-native plants are identified at a single location: splitlip hempnettle
(Galeopsis bifida), pineappleweed (Matricaria discoidea), common sheep sorrel (Rumex
acetosella), and common dandelion (Taraxacum officinale spp. officinale; AKNHP 2019a).
On August 8–10, 2023, a 2-person team conducted a non-native plant survey along the portage
trail and near the temporary biological research camp associated with the feasibility efforts for
the Project. The portage trail was a focus for non-native plant species because it experiences
heavy human traffic. Two observers walked the portage trail in both directions. Time was spent
investigating the areas around both trail termini and the research camp. Non-native, invasive, or
exotic plant occurrences listed in the PAD or other known non-native plants were not observed
during the survey.
During the vegetation survey and wetland delineation from August 8-15, 2023, the team also
visually assessed the presence of any non-native plants within the Project facility study area. No
non-native plants were found during either of these surveys in the Project facility study area.
5.2.2 Wetland Classification
NWI data is currently not available for the proposed Project area. To identify potential wetlands,
existing vegetation, hydrology, and hydric soil data were evaluated and potential wetland areas
were located based on vegetation mapping.
USACE Certified Wetland Delineators conducted field activities from August 8-13, 2023, using
the three-parameter approach in accordance with Part IV of the Corps of Engineers Wetlands
Delineation Manual (USACE, 1987) and the Regional Supplement to the Corps of Engineers
Wetland Delineation Manual: Alaska Region (Version 2.0; USACE, 2007).
The 97.59 acre Project facility study area was predominantly designated as uplands (92.72 acres)
with 4.87 acres of wetlands. The results of the detailed Project facility study area delineation are
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shown in Figure 5-9 and Figure 5-11. Details of how the study was performed are provided in the
Nuyakuk River Hydroelectric Project Facility Wetland Delineation Report (Appendix K-2).
Wetlands within the Project facility study area all classified as palustrine systems (Table 5-2).
Palustrine systems include all nontidal wetlands dominated by trees, shrubs, persistent emergent
plants, emergent mosses or lichens, and areas within tidal systems where ocean-derived salinities
are less than 0.05%. This system encompasses most wetlands referred to as marshes, swamps,
bogs, fens, and wet prairies under other classification systems. They are often found within or
adjacent to riverine and lacustrine systems (Cowardin, et. Al. 1979).
Three separate palustrine wetland classifications were identified, with delineated boundaries,
within the Project facility study area (Table 5-2). The identified palustrine wetlands include a
wetland delineated outside the Project facility study area, which was investigated due to
observations on aerial imagery. The location and boundaries of the wetlands are indicated in
Figure 5-11. The delineated wetland classifications and acreage are also shown in Figure 5-11.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
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Table 5-2. Delineated wetland types and area.
Type1 Classification Modifier Area (acres)
Area 2 PEM Seasonally Flooded/Saturated Persistent
Palustrine Emergent Wetland
PEM1E 0.63
Area 5 PEM Saturated Persistent Palustrine Emergent
Wetland
PEM1B 0.01
Area 4 PSS Saturated Broad-Leaved Deciduous Palustrine
Scrub-Shrub Wetland
PSS1B 0.45
Area 1 PSS Intermittently Flooded Broad-Leaved
Deciduous Palustrine Scrub-Shrub Wetland
PSS1J 0.31
Area 3 PUB Permanently Flooded Sand Palustrine
Unconsolidated Bottom Wetland
PUB2H 3.49
Total 4.89
1Wetlands are delineated by Cowardin classification including modifiers (Cowardin et al. 1979).
5.2.2.1 Palustrine Emergent Wetlands
Palustrine Emergent (PEM) wetlands in freshwater systems are dominated by persistent
emergent plants. Vegetation is usually dominated by perennial, emergent plants (i.e., erect,
rooted, herbaceous hydrophytes) are the tallest life form with at least 30 percent coverage. This
vegetation is present for most of the growing season in most years (FGDC 2013).
PEM wetland types in the Project area include Seasonally Flooded/Saturated (PEM1E) and
Saturated (PEM1B) Persistent Palustrine Emergent wetlands.
The Area 2 PEM1E wetlands were classified at sample points PF-02 and PF-04. They have a 70
to 75 percent cover of water sedge (Carex aquatilis), an obligate wetland plant. These wetlands
are located around the edge of the pond and are inundated for at least part of the growing season.
They cover approximately 0.63 acres, or 0.6% of the Project facility study area.
The PEM1B wetlands at sample points PF-07 and PF-13 are sedge complex wetland with 90 to
95 percent sedge cover. These areas are likely saturated for most or all of the growing season.
At Area 5 PF-07, the dominant plant is few-flower sedge (Carex pauciflora), an obligate wetland
plant. This area was a very small patch of sedge wetlands within a larger scrub-shrub wetland
(Area 4, described in Section 5.2.2.2); the area totaled no more than 0.01 acres.
At sample point PF-13, the dominant sedge is Bigelow’s sedge (C. bigelowii). These areas are
likely saturated for most or all of the growing season. No area was calculated for the wetland at
sample point PF-13, as only the border accessible from and adjacent to the Project area was
mapped.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 24 December 2023
Figure 5-10. PEM wetlands found southeast of the Project facility study area at sample point PF-
13.
5.2.2.2 Palustrine Scrub-Shrub Wetland
Palustrine Scrub-Shrub (PSS) wetlands include all freshwater wetlands dominated by woody
plants less than 20 ft tall. Shrubs includes true shrubs, young specimens of tree species that have
not yet reached 20 ft in height, and woody plants (including tree species) that are stunted because
of adverse environmental conditions (Flagstad et al. 2018). PSS wetlands are characterized by
greater than 30 percent aerial cover in the shrub layer (FGDC 2013).
PSS wetland types in the Project area include Saturated (PSS1B) and Intermittently Flooded
(PSS1J) Broad-Leaved Deciduous Palustrine Scrub-Shrub wetlands.
The Area 4 PSS1B wetlands were classified at sample point PF-08. They have a robust scrub-
shrub layer of cloudberries (Rubus chamaemorus) with 70 percent coverage, bog blueberry
(Vaccinium uliginosum) with 40 percent coverage, and rusty Labrador-tea (Rhododendron
groenlandicum) with 5 percent coverage and an herbaceous layer of mud sedge (Carex limosa).
Wetland vegetation is dominantly FAC, FACW, and OBL. These wetlands are located near the
edge of sparse forest canopy and covered 0.45 acres, or 0.5% of the Project facility study area.
The Area 1 PSS1J wetlands were classified at sample point PF-18. They have a scrub-shrub layer
of Richardson's willow (Salix richardsonii) with 60 percent coverage with a predominate
herbaceous layer of bluejoint grass (Calamagrostis canadensis). Wetland vegetation is
dominantly FAC and FACW. These wetlands are located adjacent to the Nuyakuk River and
cover 0.31 acres or 0.3% of the Project facility study area.
5.2.2.3 Palustrine Unconsolidated Bottom
Palustrine Unconsolidated Bottom (PUB) wetlands include small, shallow, permanent, or
intermittent freshwater bodies which occupy less than 20 acres. The Unconsolidated Bottom
class includes all wetlands with at least 25 percent cover of particles smaller than stones and a
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vegetative cover less than 30 percent. Substrates may be cobble-gravel, sand, mud, or organic
(FGDC 2013).
The Area 3 PUB2H wetland is a 3.49-acre freshwater pond in the center of the Project area as
identified adjacent to sample point PF-05, or 3.6 % of the Project facility study area.
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6.0 DISCUSSION AND FINDINGS
6.1 General Vegetation Type/Wetland Mapping
The goal of the ISR is to document study results and analysis from year 1 of the study program.
This report refines existing vegetation and wetland mapping through desktop analysis to assess
Project impacts on these resources. Sedge Wetlands, as an ecosystem, cover an extensive
geographic area of Western Alaska and subsequently this Project area (Boggs 2019). Further
analysis and study into impacts from this Project to the Sedge Wetlands ecosystem is
recommended.
As shown on the estimated wetlands on Sheet 5a in Appendix K-1, the current proposed
transmission lines would likely not avoid filling wetlands or WOTUS. However, impacts to these
wetlands would be minimal. The current conceptual design calls for impacts to wetlands to be
limited to just the areas filled by the transmission poles or towers. Clear cutting between poles is
not planned in the conceptual transmission design plan. For example, the proposed transmission
line leaving the Project facility would pass through a dense area of wetlands directly south of the
delineated Project facility study area. Transmission lines could be routed to avoid filling
wetlands in many locations within this dense area of wetlands.
Between Ekwok and Levelock the estimated wetland area is also very dense as shown on Sheet
5a, Appendix K-1. However, some sections of the transmission line may be routed to avoid most
wetlands between the first junction and Ekwok as well as the proposed transmission line between
the second junction and Koliganek Appendix K-1, Sheet 5a.
It is anticipated that much of the transmission line can be routed outside of wetland areas. In the
areas where there is a high probability of wetlands, as shown on the mapping described above,
impacts cannot be avoided. These impacts, however, would be limited to transmission pole
footprints. The aboveground electrical transmission wire span between the poles and would not
impact wetlands.
Field Vegetation Surveys/Wetland Delineation
6.2.1 Vegetation
General vegetation classes in the Project and along the transmission route are common
representatives of the habitat found in the region. With the exception of some limited rare plant
potential (discussed in Section 6.2.1.1), the vegetation within the Project study area is not unique
to the area.
6.2.1.1 Rare Plants
One rare plant, the P. tschuktschorum, was potentially identified during the 2023 field vegetation
survey on the north side of the proposed Project facility outfall within a delineated wetland
(Figure 5-7). The identification was not confirmed because the P. tschuktschorum is so closely
related to the P. pumila and the two plants exhibit subtle morphological differences that it can be
difficult to differentiate between the two species. The two plants can also co-exist in the same
habitat, increasing the difficulty in confirming the identification. Furthermore, the two plants can
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 28 December 2023
hybridize, adding to the complexity of identification. Samples were not collected in 2023
because of the small number of plants found in the area (n=12). After consultation with ACCS, it
was determined that portions of the plant could be sampled and submitted to ACCS for
identification in 2024.
6.2.1.2 Non-native Plants
Non-native, invasive, or exotic plants were not identified or observed during the survey.
Continued monitoring for non-natives before, during and after construction of the proposed
Project would help minimize impacts from non-native species. Additional mitigation measures,
such as removal of soils and trapped seeds from construction and camp facility equipment prior
to mobilization, should be implemented during construction and operation to prevent the
introduction of invasive species to these areas.
6.2.2 Wetlands
The 97.59 acres Project facility study area is predominantly uplands (92.72 acres) with 4.87
acres of wetlands. The wetlands include 0.93 acres of Palustrine Emergent Wetland (sedge
meadow), 0.44 acres Palustrine Scrub-Shrub Wetland (shrub meadow), and 3.49 acres of
Palustrine Unconsolidated Bottom Wetland (pond).
Where possible and as time allowed, investigation was extended beyond transects and outside the
assigned Project facility study area boundary. To the southeast of the facility study area, a large
sedge wetland was visited to facilitate comparison with sedge data throughout the transmission
line study area. This wetland area is clearly visible in aerial photography and the Wetland sedge
data, which was mapped, so this confirmed the utility of those data sets for identifying wetlands
in the larger Project area.
6.3 Overview
The overall findings from this study can be used to refine the placement of the Project facility
components and the transmission line. However, further vegetation and wetland analysis as well
as empirical evidence of the mapped areas is necessary to better understand the overall terrain of
the Project area.
Project impacts would result from the construction of Project facility components as well as
transmission line facilities. Project facility components would include an air strip, facility
housing and access roads, intake house, powerhouse, and tailrace (Figure 5-11). Layout of those
facilities would be placed so as to avoid impacts to wetlands and WOTUS to the extent
practicable, but some unavoidable impacts could be anticipated at either end of the Project’s
intake tunnel. The proposed transmission line infrastructure is expected to comprise support
poles spaced at 200 to 800 feet along the transmission route, for a total of roughly 1780 poles.
Each pole would have a relatively small footprint (~0.4 acre) in relation to total project area of
1,227 acres. The goal would be to route the transmission line, where possible, away from
wetlands and along higher terrain and ridgelines to limit project impacts.
Project area vegetation, with the exception of limited rare plant sightings, is typical for the region
and provides no special habitat. No invasive species are currently found within the Project
Facility study area. Impacts from invasive species during Project construction and operation can
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 29 December 2023
be mitigated through best management practices such as the cleaning of equipment and materials
prior to mobilization and utilization at the Project facility.
Project construction in WOTUS will require USACE permitting, and unavoidable impacts will
require mitigation. Impacts that cannot be avoided or mitigated will be offset using direct
compensatory mitigation. USACE aspires to no net loss of wetlands through their permitting
process, so the overall impacts to wetlands and WOTUS are expected to be negligible.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no variances to the FERC’s approved study plan and/or any modifications made
during study implementation.
8.0 STUDY STATUS AND SCHEDULE
8.1 General Vegetation Type/Wetland Mapping
General vegetation type and wetland mapping was completed per the study plan outlined in the
RSP.
8.2 Rare Plants
The rare plant, the P. tschuktschorum, was potentially observed during the vegetation survey. To
accurately identify whether the Primula spp. was a P. tschuktschorum or the P. pumila
(commonly mistaken for a P. tschuktschorum), samples of the Primula spp. would need to be
submitted to ACCS for plant identification. The following procedures would allow for accurate
identification of the plant:
Obtain necessary permits for plant collection.
Collect plant samples.
Submit plant samples to ACCS for plant identification.
8.2.1 Schedule
Table 8-1. Rare plant identification schedule.1
Task Year Duration Comment
Permit 2024 90 days Spring 2024
Field work/plant collection 2024 1 day 2024 summer field season
Submit sample for identification 2024 30 days
1The schedule is an approximation and may vary depending on plant identification processes.
8.3 Wetland Functional Assessment
The wetland functional assessment is still ongoing. It will be completed during the fall of 2023
and reported on in the Updated Study Report (USR).
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 30 December 2023
9.0 STUDY-SPECIFIC CONSULTATION
MLP&A consulted agencies and resources during the study via meetings and correspondence
(Table 9-1).
Table 9-1. Vegetation and wetland delineation agency consultation history.
Date Consultation Description
Vegetation Mapping / Wetland Delineation
02/17/2023 –
05/15/23023
Email – Maria Lewis and Erin Novakovich (MLP&A) and Timm
Nawrocki (UAA) to determine and implement the best land cover use
data/vegetation map data for Project area. Preliminary survey of plant
species list from AKVEG Database.
02/17/2023 –
03/01/2023
Email – Erin Novokovich (MLP&A) and Sydney Thielke (FWS)
regarding the availability of wetlands data in Wood Tikchick/ Bristol
Bay area. While there is mapping currently ongoing throughout the
region, there were no Projects encompassing the Project area at this
time.
03/31/2023 Email – Erin Novokovich (MLP&A) and Sydney Thielke (FWS)
regarding discussion about the NWI.
04/28/2023 –
05/01/2023
Email – Maria Lewis (MLP&A) and Ryan Winn (USACE) to verify a
PCN for wetland delineation activities was not required.
5/25/2023 Virtual Meeting – Maria Lewis and Erin Novakovich (MLP&A) and
Timm Nawrocki (UAA) to discuss vegetation data mapping.
05/24/2023 –
05//30/2023
Email – Maria Lewis and Erin Novakovich (MLP&A) and Timm
Nawrocki (UAA) Follow-up after zoom meeting RE vegetation
mapping.
09/11/2023 Virtual Meeting – Maria Lewis and Lindsey Kendall (MLP&A) to
discuss vegetation data mapping to predict wetland type.
Rare Plants
8/12/23 Email – MLP&A to ACCS – Rare plant identification
8/15/23 Email – ACCS to MLP&A – Primula spp. identification
8/16/23 Email – MLPA to ACCS – Discussion on P. tschuktschorum and the P.
pumila
8/18/23 Phone Correspondence – MLP&A and ACCS - P. tschuktschorum and
the P. pumila and options for identification.
8/18/23 Email – ACCS to MLP&A – DNA identification of Primula spp.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 31 December 2023
10.0 REFERENCES
ADNR. 2002. Wood-Tikchik State Park Management Plan. Division of Parks and Outdoor
Recreation. October 2002. Available at:
<http://dnr.alaska.gov/parks/plans/woodt/woodtpln.htm>.
AKNHP. 2019b. Alaska Rare Plants Occurrences database
<http://aknhp.uaa.alaska.edu/apps/rareplants>. Alaska Center for Conservation Science,
University of Alaska, Anchorage. Accessed January 15, 2019.
Alaska Center for Conservation Science (ACCS). Undated. Vegetation Ecology and Botany.
People. <https://accs.uaa.alaska.edu/vegetation/>. Accessed October 6, 2023.
Boggs, K., L. Flagstad, T. Boucher, M. Carlson, A. Steer, B. Bernard, M. Aisu, P. Lema, B.
Heitz, and T. Kuo. 2019. Alaska Ecosystems of Conservation Concern: Biophysical
Settings and Plant Associations. Report prepared by the Alaska Center for Conservation
Science, University of Alaska, Anchorage for the Alaska Department of Fish and Game.
Carlson, M. L. 2006. Natural Threats to the Rare Arctic Primrose, Primula Tschuktschorum:
Goose Grazing and Reproductive Interference with Its Sister Species. Alaska Natural
Heritage Program, Environment and Natural Resources Institute, University of Alaska.
January 2006.
Cowardin, L. M., V. Carter, F. C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Department of the Interior, Fish and
Wildlife Service, Office of Biological Services, Washington, D.C. FWS/OBS-79/31.
December, 1979, Reprinted 1992. https://www.fws.gov/wetlands/documents/
Classification-of-Wetlands-and-Deepwater-Habitats-of-the-United-States.pdf
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical
Report Y-87-1. U.S. Army Corps of Engineers, Waterways Experiment Station,
Vicksburg, Mississippi. January, 1987. https://el.erdc.dren.mil/elpubs/pdf/wlman87.pdf
Federal Geographic Data Committee. 2013. Classification of wetlands and deepwater habitats of
the United States. FGDC-STD-004-2013. 2nd Edition. Wetlands Subcommittee, Federal
Geographic Data Committee and USFWS, Washington, DC. August 2013.
https://www.fws.gov/wetlands/documents/Classification-of-Wetlands-and-Deepwater-
Habitats-of-the-United-States-2013.pdf
Flagstad, L., M. A. Steer, T. Boucher, M. Aisu, and P. Lema. 2018. Wetlands across Alaska:
Statewide wetland map and assessment of rare wetland ecosystems. Alaska Natural
Heritage Program, Alaska Center for Conservation Science, University of Alaska
Anchorage. 151 pages.
Flagstad, L., Cortes-Burns, H., and Greenstein, C. 2019. Identification of Non-native Plants in
Alaska. Alaska Natural Heritage Program, University of Alaska Anchorage.
Nuyakuk River Hydroelectric Project Botanical and Wetlands Survey
FERC No. 14873 Initial Study Report – Attachment K
Nushagak Cooperative, Inc. 32 December 2023
Gallant, A.L., E.F. Binnian, J.M. Omernik, and M.B. Shasby. 1995. Ecoregions of Alaska. USGS
Professional Paper 1567, Washington.
Munsell Color. 2009. Munsell Soil-Color Charts. Munsell Color. Grand Rapids, MI. Produced
2013.
Nawrocki, T., J. Fulkerson, and M. Carlson. 2013, Alaska Rare Plant Field Guide. Alaska
Natural Heritage Program, University of Alaska Anchorage. 2013.
Nawrocki, T.W., M.L. Carlson, A.F. Wells, M.J. Macander, E. Jamie Trammell, F.D.W. Witmer,
C.A. Roland, K. Baer, and D.K. Swanson. 2021. Continuous Foliar Cover of Plant
Species and Aggregates in North American Beringia. Map User Guide and Accuracy
Assessment. Version 1.0 (May 2021). Available: https://doi.org/10.5281/zenodo.3897482
UAA (University of Alaska Anchorage). 2020. Non-Native Plant Species List. Alaska Center for
Conservation Science. Available online at: https://accs.uaa.alaska.edu/invasive-
species/nonnative-plant-species-list/. Accessed March 4, 2020.USACE. 1987.
UAA. 2023. Continuous Foliar Cover of Plant Species and Aggregates in North American
Beringia Dataset. Online at: https://accscatalog.uaa.alaska.edu/dataset/continuous-foliar-
cover-plant-species-and-aggregates-north-american-beringia. Accessed May 2023.
USACE (U.S. Army Corps of Engineers). 1987. Corps of Engineers Wetlands Delineation
Manual. Wetlands Research Program Technical Report Y-87-1. January 1987.
USACE. 2007. Regional Supplement to the Corps of Engineers Wetland Delineation Manual:
Alaska Region (Version 2.0), ed. J. S. Wakeley, R. W. Lichvar, and C. V. Noble.
ERDC/EL TR-07-24. Vicksburg, MS: U.S. Army Engineer Research and Development
Center. September 2007.
USDA, NRCS. 2023 Web Soil Survey. Natural Resources Conservation Service, U.S.
Department of Agriculture. Accessed 2023. https://websoilsurvey.nrcs.usda.gov/app/
USGS (United States Geological Survey). 2023. USGS National Hydrographic Dataset. Online
at: https://www.usgs.gov/national-hydrography/access-national-hydrography-products.
Accessed August 2023.
Viereck, L. A., C. T. Dyrness, A. R. Batten, and K. J. Wenzlick. 1992. The Alaska Vegetation
Classification. PNW-GTR-286. Portland, OR: U.S. Department of Agriculture, Forest
Service, Pacific Northwest Research Station. Online at https://doi.org/10.2737/PNW-
GTR-286.
APPENDIX -:
APPENDIX -2:
Preliminary
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
606
0
190
Carex aquatilis
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
Yes
92
Calamagrostis canadensis
183
OBL
1 No
Equisetum sylvaticum
4 2
444
2
FACU
40Picea glauca 10 No FACU 160
Multiply by:
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 83.3%
Tree Stratum
Precipitation has been higher than average for this season.
PF-01
Sampling Date:
Sampling Point:
8/9/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
2
0
Total % Cover of:
15
20
20
20 Yes
80
FAC
YesBetula papyrifera
FACYes
data in Remarks or on a separate sheet)
FAC
15' RAD
2
4
Yes
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
7
Prevalence Index is 3.01
No
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes FAC
Prevalence Index = B/A =
148
3.19
No
Prevalence Index worksheet:
FACU species
37
=Total Cover
Herb Stratum
None Slope (%):
Betula nana
Empetrum nigrum
FAC species
FAC
FAC
Rhododendron groenlandicum
Vaccinium uliginosum
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11961259.906282 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
5
6
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in
diameter at breast height (DBH), regardless of
height.
Use scientific names of plants.PF-01
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants,
regardless of size.
Definitions of Vegetation Strata:
Spiraea stevenii 10 No FACU
=Total Cover
Sapling/Shrub Stratum
Vaccinium vitis-idaea 8 No FAC
183 =Total Cover
Herb Stratum
Remarks:
24
7 =Total Cover
92 37
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
15
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
7.5YR 2.5/2
7.5YR 2.5/2
Very Shallow Dark Surface (F22)
Redox Features
Sandy
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
4 - 4 1/2
14-17
12-14 7.5R 2.5/1
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
4 1/2 -12 Sandy
Peat
Sandy
5YR 3/3
PF-01SOIL
sandy loam
sandy loam
sandy loam
Remarks
1-4
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long:
Soil Map Unit Name:
N
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil Y , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
237
0
129
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
25
Iris setosa
50
4 No
Carex aquatilis
40 16
162
75
0 0
Multiply by:
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Tree Stratum
Precipitation has been higher than average for this season.
PF-02
Sampling Date:
Sampling Point:
8/9/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
75
0
Total % Cover of:
50 FACYes
data in Remarks or on a separate sheet)
FAC
5' X 10'
75
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
79
Prevalence Index is 3.01
No
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes OBL
Prevalence Index = B/A =
54
1.84
Prevalence Index worksheet:
FACU species
10
=Total Cover
Herb Stratum
Slope (%):
FAC species
Vaccinium uliginosum
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
158.119723°59.906220 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
2
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes X No
Primary Indicators (any one indicator is sufficient)
X
X
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
7.5YR 3/3
Very Shallow Dark Surface (F22)
Redox Features
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
7 1/2 - 10
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
10-12 Sandy
Peat
10YR 3/2
PF-02SOIL
Loamy Sand
Sandy Loam
Remarks
0 - 7 1/2
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
The sample points in the depression surrounding this pond have sandy soils that may represent recently formed soils, as there is low organic
content. The size of the pond and surrounding emergent wetlands appears to be expanding. These soils will be considered problematic hydric
soils, taken in conjunction with the presence of clear vegetation and hydrology indicators.
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
5
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
Slope (%):
Betula papyrifera
Spiraea stevenii
FAC species
FACU
FACU
Vaccinium vitis-idaea
Vaccinium uliginosum
<2%
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11969159.906339
Betula papyrifera
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
90
Yes FAC
Prevalence Index = B/A =
104
3.15
No
Prevalence Index worksheet:
FACU species
35
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
6
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
FAC
15' RAD
5
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
45
Total % Cover of:
10
45
20
25 No
60
FAC
YesRubus chamaemorus
FACYes
25 10
Tree Stratum
Precipitation has been higher than average for this season.
PF-03
Sampling Date:
Sampling Point:
8/9/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Terrace
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50
40
10
FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Yes
Sapling/Shrub Stratum
20% of total cover: 60.0%
Calamagrostis canadensis
173
1 No
Equisetum sylvaticum
3 2
312
0
FACW
80Empetrum nigrum 8 No FAC 320
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
722
0
229
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
87
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
25 10
87 35
Remarks:
23
6 =Total Cover
173 =Total Cover
Herb Stratum
No FAC
50 =Total Cover
Sapling/Shrub Stratum
Cornus suecica 5
Use scientific names of plants.PF-03
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants,
regardless of size.
Definitions of Vegetation Strata:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in
diameter at breast height (DBH), regardless of
height.
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-03SOIL
Sandy Loam
Remarks
0-4
Color (moist)
Depth
(inches)
Redox Features
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
4-16
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
Peat
Matrix
Color (moist)
Black Histic (A3)
7.5YR 4/2
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil Y , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
4
5
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
Slope (%):
Betula nana
FAC species
FAC
Spiraea stevenii
Vaccinium uliginosum
<2%
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.12078459.905723
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes OBL
Prevalence Index = B/A =
60
1.95
Prevalence Index worksheet:
FACU species
2
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
125
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
FAC
15' X 5'
15
70
Yes
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
70
0
Total % Cover of:1
2
2 Yes
2
FACU
NoVaccinium vitis-idaea
FACYes
Tree Stratum
Precipitation has been higher than average for this season.
PF-04
Sampling Date:
Sampling Point:
8/9/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 80.0%
Iris setosa
7
FAC
40 Yes
Carex aquatilis
63 25
180
70
FAC
2 8
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
258
0
132
Calamagrostis canadensis
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
No
4
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes No
Primary Indicators (any one indicator is sufficient)
X
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
The sample points in the depression surrounding this pond have sandy soils that may represent recently formed soils, as there is low organic
content. The size of the pond and surrounding emergent wetlands appears to be expanding. These soils will be considered problematic hydric
soils, taken in conjunction with the presence of clear vegetation and hydrology indicators.
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-04SOIL
Loamy Sand
Loamy Sand
Remarks
0-3
Color (moist)
Depth
(inches)
Redox Features
Peat
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
3-6
10-16 2.5Y 4/2
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
6-10 Sandy
Peat
10YR 4/3
Matrix
Color (moist)
Black Histic (A3)
7.5YR 4/2
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil Y , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
270
0
139
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
30
Calamagrostis canadensis
59
10 No
Carex aquatilis
40 16
186
70
FAC
0 0
Multiply by:
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Tree Stratum
Precipitation has been higher than average for this season.
PF-05
Sampling Date:
Sampling Point:
8/9/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
70
7
Total % Cover of:10
2
7 No
40
FACW
NoVaccinium uliginosum
FACYes
data in Remarks or on a separate sheet)
FAC
15' RAD
70
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
80
Prevalence Index is 3.01
No
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
14
Yes OBL
Prevalence Index = B/A =
62
1.94
Prevalence Index worksheet:
FACU species
12
=Total Cover
Herb Stratum
none Slope (%):
Vaccinium vitis-idaea
FAC species
FAC
Rubus chamaemorus
Betula nana
<2%
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11959459.904967 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
2
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes No
Primary Indicators (any one indicator is sufficient)
X
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
4
1
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
7.5YR 5/2
Very Shallow Dark Surface (F22)
Redox Features
Mucky Peat
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
6-13
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
13-18 Sandy
Peat
10YR 3/4
PF-05SOIL
Loamy Sand
Remarks
0-6
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Hole was so completely saturated with water that no other layers could be identified beyond 18 inches. Problematic soils present.
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s)
Local relief (concave, convex, none):
Subregion: Lat:Long
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
538
0
167
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
79
157
390
0
FAC
37Betula papyrifera 2 No FACU 148
Multiply by:
30
30 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 66.7%15 6
Tree Stratum
Precipitation has been higher than average for this season.
PF-06
Sampling Date:
Sampling Point:
8/10/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Hillside
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
5
40
20
30 No
60
FAC
YesEmpetrum nigrum
FACYes
data in Remarks or on a separate sheet)
15' RAD
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
Betula papyrifera
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Prevalence Index = B/A =
130
3.22
No
Prevalence Index worksheet:
FACU species
32
=Total Cover
Herb Stratum
none Slope (%):
Spiraea stevenii
Betula glauca
FAC speciesFACU
Vaccinium uliginosum
Rhododendron groenlandicum
<15%
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11934357.911240 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
None
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
10YR 4/4
10R 2.5/1
2.5YR 2.5/1
Very Shallow Dark Surface (F22)
19
Redox Features
Mucky Peat
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
4-7
11-13
8-11 2.5YR 2.5/1
Texture
Sandy
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
7-8
Peat
Sandy
7.5YR 6/2
PF-06SOIL
Ash layer
Remarks
0-4
Color (moist)
Depth
(inches)
13-19
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
Rocks
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
N
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4. X
5. N/A
6.
7. N/A
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
112
0
98
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
4
Drosera rotundifolia
7
1 No
Carex pauciflora
46 19
21
91
FAC
0 0
Multiply by:
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Tree Stratum
Precipitation has been higher than average for this season.
PF-07
Sampling Date:
Sampling Point:
8/10/23
BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Flat
Project/Site: NRHP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
91
0
Total % Cover of:2
1
2 Yes
2
FAC
YesVaccinium uliginosum
FACYes
data in Remarks or on a separate sheet)
OBL
10 x 10 ft
90
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
N/ATotal Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
91
Prevalence Index is 3.01
No
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes OBL
Prevalence Index = B/A =
7
1.14
Prevalence Index worksheet:
FACU species
2
=Total Cover
Herb Stratum
Concave Slope (%):
Betula nana
FAC species
FAC
Rhododendron groenlandicum
Empetrium nigrum
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11651959.904839 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
4
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes X No
Primary Indicators (any one indicator is sufficient)
X
X
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
2
10
0
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
10YR 3/6
Very Shallow Dark Surface (F22)
Redox Features
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
18-20
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
Peat
PF-07SOIL
Sandy Loam
Remarks
0-18
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
none Slope (%):
Empetrum nigrum
Rhododendron groenlandicum
FAC species
FAC
FAC
Vaccinium uliginosum
Betula nana
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11645659.904793
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
140
Yes OBL
Prevalence Index = B/A =
137
2.55
No
Prevalence Index worksheet:
FACU species
42
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
25
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
15' R
25
Yes
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
25
70
Total % Cover of:
20
70
55
40 No
20
FAC
YesRubus chamaemorus
FACNo
5 2
Tree Stratum
Precipitation has been higher than average for this season.
PF-08
Sampling Date:
Sampling Point:
8/10/2023
MAL, LSK
Dillingham CensusBorough/City:
Nushagak Electric Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
10
10 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 75.0%
207
Carex limosa
13 5
411
25
FACW
10Vaccinium vitis-idaea 2 No FAC 40
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
616
0
242
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
104
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes X No
Primary Indicators (any one indicator is sufficient)
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-08SOIL
Buttery
Remarks
0-4
Color (moist)
Depth
(inches)
Redox Features
Mucky Peat
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
4-8
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
8-18 Muck
Peat
Matrix
Color (moist)
Black Histic (A3)
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
10
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes No X
Yes No X Yes X
Yes No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
503
0
161
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
68
135
Equisetum sylvaticum
1 1
303
0
FACW
40Cornus suecica 5 No FAC 160
Multiply by:
25
25 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 50.0%13 5
Tree Stratum
Precipitation has been higher than average for this season.
PF-09
Sampling Date:
Sampling Point:
8/10/2023
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): Plain
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
20
Total % Cover of:
5
20
10
15 No
80
FACU
NoRubus chamaemorus
FACYes
data in Remarks or on a separate sheet)
15' R
1
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
1
Prevalence Index is 3.01
No
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
40
No FAC
Prevalence Index = B/A =
101
3.12
No
Prevalence Index worksheet:
FACU species
27
=Total Cover
Herb Stratum
none Slope (%):
Vaccinium vitis-idaea
Vaccinium uliginosum
FAC species
FAC
FAC
Spirea steventii
Betula nana
<1
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11627359.904773 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
1
2
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
85 15 C M
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
N
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
18
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
10YR 3/4
Black Histic (A3)
Very Shallow Dark Surface (F22)
Redox Features
Mucky Peat
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
4-11
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
11-18 Loamy/Clayey
Peat
2.5Y 4/3
PF-09SOIL
Silt/Loam
Remarks
0-4
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
None Slope (%):
Spirea stevenii
FAC species
FACU
Vaccinium vitis-idaea
Vaccinium uliginosum
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11686259.904991
Betula nana
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Prevalence Index = B/A =
197
3.02
Prevalence Index worksheet:
FACU species
38
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
12x20 ft
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
0
Total % Cover of:90
1
7 No
90
FAC
YesEmpetrum nigrum
FACYes
6 3
Tree Stratum
Precipitation has been higher than average for this season.
PF-10
Sampling Date:
Sampling Point:
8/10/2023
BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): Hummock
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
12
10
2
FAC Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
No
Sapling/Shrub Stratum
20% of total cover: 100.0%
188
591
0
FAC
3 12
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
603
0
200
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
94
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-10SOIL
Sandy Loam
Clay Loam
Remarks
0-3
Color (moist)
Depth
(inches)
Redox Features
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
3-5
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
5-20 Loamy/Clayey
Peat
2.5Y 4/3
Matrix
Color (moist)
Black Histic (A3)
7.5YR 2.5/2
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
359
0
109
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
41
81
Athyrium filix-femina
4 2
231
0
FAC
32Vaccinium uliginosum 10 No FAC 128
Multiply by:
20
20 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 71.4%10 4
Tree Stratum
Precipitation has been higher than average for this season.
PF-11
Sampling Date:
Sampling Point:
8/11/2023
BLH, BK, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): None
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
3
15
12
12 Yes
17
FACU
YesEmpetrum nigrum
FACYes
data in Remarks or on a separate sheet)
20x20 ft
8
Yes
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
8
Prevalence Index is 3.01
No
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes FAC
Prevalence Index = B/A =
77
3.29
No
Prevalence Index worksheet:
FACU species
17
=Total Cover
Herb Stratum
None Slope (%):
Alnus incana
Rubus pedatus
FAC species
FAC
FAC
Spirea stevenii
Vaccinium vitis-idaea
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.12099059.903069 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
5
7
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
Use scientific names of plants.PF-11
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
20 =Total Cover
Sapling/Shrub Stratum
Vaccinium ovalifolium 12 Yes FAC
81 =Total Cover
Herb Stratum
Remarks:
24
8 =Total Cover
10 4
41 17
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
7.5YR 3/2
Very Shallow Dark Surface (F22)
Redox Features
Loamy/Clayey
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
2-5
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
5-20 Loamy/Clayey
Peat
10YR 4/4
PF-11SOIL
Loamy Sand
Loamy Sand
Remarks
0-2
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
862
0
283
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
139
278
810
0
FAC
13 52
Multiply by:
5
5 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 66.7%3 1
Tree Stratum
Precipitation has been higher than average for this season.
PF-12
Sampling Date:
Sampling Point:
8/11/2023
BLH, BK, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): Hillside
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
8
75
55
55 No
85
FAC
YesVaccinium vitis-idaea
FACYes
data in Remarks or on a separate sheet)
20x20 ft
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Prevalence Index = B/A =
270
3.05
No
Prevalence Index worksheet:
FACU species
56
=Total Cover
Herb Stratum
none Slope (%):
Spiraea stevenii
Rhododendron groenlandicum
FAC species
FAC
FACU
Vaccinium uliginosum
Empetrum nigrum
2
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.12184159.903354 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
90 10 CS M
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
5YR 2.5/2
Black Histic (A3)
5YR 2.5/2
Very Shallow Dark Surface (F22)
Redox Features
Loamy/Clayey
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
3-5
14-20 2.5Y 5/3
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
5-14 Loamy/Clayey
Peat
7.5YR 4/4
PF-12SOIL
Veg mat
Loamy Sand
Loamy Sand, distinct patches
Slight loam, mostly sand
Remarks
0-3
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
None Slope (%):
Betula nana
FAC species
FAC
Rubus chamaemorus
Empetrum nigrum
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11616759.901487
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
10
Yes FAC
Prevalence Index = B/A =
132
2.89
Prevalence Index worksheet:
FACU species
9
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
100
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
OBL
10x10 ft
95
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
5
5
Total % Cover of:15
2
5 No
20
FACW
YesRhododendron groenlandicum
FACYes
Tree Stratum
Precipitation has been higher than average for this season.
PF-13
Sampling Date:
Sampling Point:
8/11/2023
LSK, BK, BLH
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): None
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Drosera rotundifolia
42
5 No
Carex bigelowii
50 20
396
5
FAC
0 0
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
411
0
142
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
21
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes X No
Primary Indicators (any one indicator is sufficient)
X
N
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-13SOIL
Remarks
0-20
Color (moist)
Depth
(inches)
Redox Features
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
Peat
Matrix
Color (moist)
Black Histic (A3)
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
16
0
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
4
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
concave Slope (%):
FAC species
Betula nana
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11680259.901172
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
10
Yes FAC
Prevalence Index = B/A =
135
2.53
Prevalence Index worksheet:
FACU species
8
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
140
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
OBL
20 x 20 ft
5
95
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
40
5
Total % Cover of:20
20
YesSalix alaxensis
FACYes
Tree Stratum
Precipitation has been higher than average for this season.
PF-14
Sampling Date:
Sampling Point:
8/11/2023
BLH, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): bottom of hill
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
Number of Dominant Species That
Are OBL, FACW, or FAC:
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Comarum palustre
40
FACW
40 Yes
Calamagrostis canadensis
70 28
405
40
FAC
0 0
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
455
0
180
Equisetum pratense
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
No
20
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
X
X
X
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes X No
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-14SOIL
silt
silty loam
Remarks
0-7
Color (moist)
Depth
(inches)
Redox Features
Loamy/Clayey
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
7-12
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
12-18 Loamy/Clayey
Peat
7.5YR 2.5/2
Matrix
Color (moist)
Black Histic (A3)
10YR 4/4
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
12
0
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
No
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
5
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
concave Slope (%):
Rubus chamaemorus
Rubus pedatus
FAC species
FAC
FACW
Spiraea stevenii
Vaccinium uliginosum
1
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11786259.908396
Alnus incana
FACU
Picea glauca
Betula papyrifera
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
4
Prevalence Index = B/A =
95
3.30
No
Prevalence Index worksheet:
FACU species
23
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
15 ft R
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
2
Total % Cover of:
2
20
15
20 Yes
35
FACU
YesBetula nana
FACYes
15 6
Tree Stratum
Precipitation has been higher than average for this season.
PF-15
Sampling Date:
Sampling Point:
8/12/23
MAL, BLH, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): none
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
30
15
10
5
FAC Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Yes
Sapling/Shrub Stratum
20% of total cover: 60.0%
112
285
0
FAC
45Betula papyrifera 5 No FACU 180
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
469
0
142
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
56
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
15 6
56 23
Remarks:
=Total Cover
112 =Total Cover
Herb Stratum
No FACU
Vaccinium vitis-idaea 5 No FAC
Ribes bracteosum 5
30 =Total Cover
Sapling/Shrub Stratum
Spinulum annotinum 5
No FAC
Use scientific names of plants.PF-15
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-15SOIL
Clay Loam
Ash
Sandy Loam
Loamy Sand
Remarks
0-1
Color (moist)
Depth
(inches)
Redox Features
Loamy/Clayey
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
1-4
9-20
5-9 5YR 2.5/2
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
4-5 Sandy
Peat
Sandy
5YR 4/2
Matrix
Color (moist)
Black Histic (A3)
7.5YR 4/6
5YR 2.5/2
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
none Slope (%):
Spiraea stevenii
Vaccinium uliginosum
FAC species
FAC
FACU
Rhododendron groenlandicum
Empetrum nigrum
5
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11371459.907171
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
6
Prevalence Index = B/A =
220
3.07
No
Prevalence Index worksheet:
FACU species
47
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
15 ft R
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
3
Total % Cover of:
10
60
30
50 Yes
75
FAC
YesBetula nana
FACYes
5 2
Tree Stratum
Precipitation has been higher than average for this season.
PF-16
Sampling Date:
Sampling Point:
8/12/2023
BLH, BK, MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): gentle hill
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
10
10 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 75.0%
233
660
0
FAC
20Vaccinium vitis-idaea 5 No FAC 80
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
746
0
243
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
117
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
5 2
117 47
Remarks:
=Total Cover
233 =Total Cover
Herb Stratum
No FACW
10 =Total Cover
Sapling/Shrub Stratum
Rubus chamaemorus 3
Use scientific names of plants.PF-16
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Y
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
Rock
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-16SOIL
Loamy Sand
Sandy Loam
Sandy Loam
Loamy Sand
Remarks
0-6
Color (moist)
Depth
(inches)
16-17
Redox Features
Mucky Peat
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
6-9
13-16
10-13 7.5YR 2.5/2
Texture
Loamy/Clayey
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
9-10 Loamy/Clayey
Peat
Sandy
10YR 7/3
Matrix
Color (moist)
Black Histic (A3)
2.5Y 3/3
10YR 3/6
Very Shallow Dark Surface (F22)
17
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
710
0
231
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
113
226
624
0
FAC
20Empetrum nigrum 8 No FAC 80
Multiply by:
5
5 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 66.7%3 1
Tree Stratum
Precipitation has been higher than average for this season.
PF-17
Sampling Date:
Sampling Point:
8/12/2023
MAL, LSK, BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Hydroelectric
Landform (hillside, terrace, hummocks, etc.): Hummocks
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
3
Total % Cover of:
15
50
30
45 No
75
FAC
YesBetula nana
FACYes
data in Remarks or on a separate sheet)
15 ft R
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
6
Prevalence Index = B/A =
208
3.07
No
Prevalence Index worksheet:
FACU species
46
=Total Cover
Herb Stratum
none Slope (%):
Spiraea stevenii
Vaccinium vitis-idaea
FAC species
FAC
FACU
Vaccinium uliginosum
Rhododendron groenlandicum
2
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11143659.906530 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
Use scientific names of plants.PF-17
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
5 =Total Cover
Sapling/Shrub Stratum
Rubus chamaemorus 3 No FACW
226 =Total Cover
Herb Stratum
Remarks:
=Total Cover
3 1
113 46
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Y
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
2.5YR 2.5/2
Very Shallow Dark Surface (F22)
20
Redox Features
Sandy
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
7-13
17-20 10YR 4/3
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
13-17 Sandy
Peat
2.5YR 3/3
PF-17SOIL
Sandy Loam
Loamy Sand
Sandy Clay
Remarks
0-7
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
Rock
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes Y No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes X No Yes X
Yes X No
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4. X
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
3
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
Concave Slope (%):
FAC species
Salix richardsonii
1
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11526359.908115
Salix alaxensis
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
150
Yes FAC
Prevalence Index = B/A =
90
2.46
Prevalence Index worksheet:
FACU species
12
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
117
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)5
OBL
20 ft R
5 No
10
NoPolemonium boreale
85
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
10
75
Total % Cover of:
60 FACWYes
3 1
Tree Stratum
Precipitation has been higher than average for this season.
PF-18
Sampling Date:
Sampling Point:
8/12/2023
MAL, LSK, BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Hydroelectric
Landform (hillside, terrace, hummocks, etc.): Shoreside
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
5
5 FAC Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 100.0%
Carex aquatilis
60
No
FACW
10 No
Calamagrostis canadensis
59 24
FACW
270
10
0 0
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
430
0
175
Viola epipsila
Sanguisorba canadensis
Equisetum pratense
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
2
No
30
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
2Location: PL=Pore Lining, M=Matrix.
X
Type:
Depth (inches):Hydric Soil Present? Yes X No
Primary Indicators (any one indicator is sufficient)
X
X
Surface Water Present? Yes
Water Table Present? Yes
Saturation Present? Yes Wetland Hydrology Present? Yes X No
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Soil is sandy and recently deposited in floodplain. It is likely covered by the river for part of the year.
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-18SOIL
Remarks
0-1
Color (moist)
Depth
(inches)
Redox Features
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
1-20
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
Peat
Matrix
Color (moist)
Black Histic (A3)
2.5Y 4/1
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Shoreline area with signs of flooding at higher river levels
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes No X
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
929
0
292
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
141
282
705
0
FAC
55Rubus pedatus 10 No FAC 220
Multiply by:
10
5
5
FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Yes
Sapling/Shrub Stratum
20% of total cover: 50.0%5 2
Tree Stratum
Precipitation has been higher than average for this season.
PF19
Sampling Date:
Sampling Point:
8/13/23
MAL, LSK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): Terrace
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
2
Total % Cover of:
30
60
45
45 No
85
FAC
YesBetula nana
FACYes
data in Remarks or on a separate sheet)
20 x 20 ft
No
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
Picea glauca
Betula papyrifera
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
4
Prevalence Index = B/A =
235
3.18
No
Prevalence Index worksheet:
FACU species
57
=Total Cover
Herb Stratum
none Slope (%):
Empetrum nigrum
Spiraea stevenii
FAC species
FACU
FAC
Rhododendron groenlandicum
Vaccinium uliginosum
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11902059.908388 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
Use scientific names of plants.PF19
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
Rhododendron tomentosum 2 No FACW
10 =Total Cover
Sapling/Shrub Stratum
Vaccinium vitis-idaea 5 No FAC
282 =Total Cover
Herb Stratum
Remarks:
=Total Cover
5 2
141 57
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Y
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
10YR 5/2
Very Shallow Dark Surface (F22)
16
Redox Features
Sandy
Loamy/Clayey
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
5-7
10-16 5YR 3/3
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
7-10 Loamy/Clayey
Peat
5YR 2.5/1
PF19SOIL
Ash
Loam
Loam
Remarks
0-5
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
Rock
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
527
0
159
Equisetum sylvaticum
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
No
10
Calamagrostis canadensis
20
FAC
2 No
Athyrium filix-femina
45 18
327
0
50 200
Multiply by:
50
45
5
FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
No
Sapling/Shrub Stratum
20% of total cover: 66.7%25 10
Tree Stratum
Precipitation has been higher than average for this season.
PF20
Sampling Date:
Sampling Point:
8/13/2023
BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): Hilltop
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
20 FACYes
data in Remarks or on a separate sheet)
FAC
20 x 20 ft
7
80
OBL species
UPL species
FACW species
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
89
Prevalence Index is 3.01
No
Betula papyrifera
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Yes FAC
Prevalence Index = B/A =
109
3.31
Prevalence Index worksheet:
FACU species
4
=Total Cover
Herb Stratum
none Slope (%):
FAC species
Alnus incana
0
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.12410959.907342 Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
Matrix
Color (moist)
Black Histic (A3)
10YR 4/3
5YR 3/2
Very Shallow Dark Surface (F22)
Redox Features
Loamy/Clayey
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
12-22
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
Sandy
PF20SOIL
Sandy loam with rocks
Loam
Remarks
0-12
Color (moist)
Depth
(inches)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes X No
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3. X
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
3
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
gentle slope Slope (%):
Vaccinium vitis-idaea
Empetrum nigrum
FAC species
FAC
FAC
Rhododendron groenlandicum
Vaccinium uliginosum
1
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.12463859.904813
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
Prevalence Index = B/A =
220
3.05
No
Prevalence Index worksheet:
FACU species
46
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
20 x 20 ft
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
15
65
30
35 No
75
FAC
YesBetula nana
FACYes
3 1
Tree Stratum
Precipitation has been higher than average for this season.
PF-21
Sampling Date:
Sampling Point:
8/13/2023
BLH, BK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): none
Project/Site: NHRP Project Site
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
5
5 FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Sapling/Shrub Stratum
20% of total cover: 66.7%
227
660
0
FAC
12Spiraea stevenii 7 No FACU 48
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
708
0
232
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
114
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-21SOIL
Loamy Sand w/ash
Loamy Sand
Loamy Sand (w/pebbles and rocks)
Remarks
0-2
Color (moist)
Depth
(inches)
Redox Features
Sandy
Sandy
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
2-5
11-20
8-11 10YR 5/8
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
5-8 Sandy
Peat
Sandy
5YR 2.5/1
Matrix
Color (moist)
Black Histic (A3)
10YR 5/4
10YR 5/3
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Applicant/Owner:
Investigator(s):
Local relief (concave, convex, none):
Subregion: Lat: Long:
Soil Map Unit Name:
X
Are Vegetation N , Soil N , or Hydrology N Are Normal Circumstances present? Yes X No
Are Vegetation N , Soil N , or Hydrology N
SUMMARY OF FINDINGS Attach site map showing sampling point locations, transects, important features, etc.
Yes No X
Yes No X Yes X
Yes No X
1.
2. (A)
3.
4. (B)
(A/B)
1.
2.
3. x 1 =
4. x 2 =
5. x 3 =
6. x 4 =
x 5 =
Column Totals: (A) (B)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Plot Size (radius, or length x width)
% Cover of Wetland Bryophytes
Yes X
Datum:
Hydric Soil Present?
(If needed, explain any answers in Remarks.)
Yes
WGS84
N/A
naturally problematic?
NWI classification:
Dominant
Species?
LRR X2, MLRA 236 (Bristol Bay-Northern Alaska Peninsula Lowlands)
Remarks:
Indicator
Status
2
4
VEGETATION Use scientific names of plants.
(If no, explain in Remarks.)
none Slope (%):
Spiraea stevenii
Betula nana
FAC species
FAC
FACU
Vaccinium uliginosum
Rhododendron groenlandicum
10
NoAre climatic / hydrologic conditions on the site typical for this time of year?
No
Western - Mosquitopoint - Typic Haplocryods
-158.11912359.907516
Betula papyrifera
Picea glauca
=Total Cover
Morphological Adaptations1(Provide supporting
Dominance Test is >50%
0
No FACU
Prevalence Index = B/A =
191
3.19
No
Prevalence Index worksheet:
FACU species
41
=Total Cover
Herb Stratum
N/A
Remarks:
(Where applicable)
% Bare Ground
Total Cover of Bryophytes
Hydrophytic
Vegetation
Present?
0
Problematic Hydrophytic Vegetation1 (Explain)
2
Prevalence Index is 3.01
No
data in Remarks or on a separate sheet)
30x30ft
2
No
OBL species
UPL species
FACW species
50% of total cover: 20% of total cover:
0
0
Total % Cover of:
10
65
20
30 No
70
FAC
YesEmpetrum nigrum
FACYes
16 7
Tree Stratum
Precipitation has been higher than average for this season.
PF-22
Sampling Date:
Sampling Point:
8/13/2023
MAL, LSK, BK
Dillingham Census AreaBorough/City:
Nushagak Cooperative
Landform (hillside, terrace, hummocks, etc.): hillside
Project/Site: NHRP Project Facility
50% of total cover:
Hydrophytic Vegetation Present?
significantly disturbed?
Is the Sampled Area
within a Wetland?
Wetland Hydrology Present?
32
25
7
FACU Number of Dominant Species That
Are OBL, FACW, or FAC:
Yes
=Total Cover
FACU
Percent of Dominant Species That
Are OBL, FACW, or FAC:
Total Number of Dominant Species
Across All Strata:
Dominance Test worksheet:
Absolute
% Cover
Yes
Sapling/Shrub Stratum
20% of total cover: 50.0%
201
Spinulum annotinum
1 1
573
0
FAC
44Rubus pedatus 5 No FAC 176
Multiply by:
U.S. Army Corps of Engineers
WETLAND DETERMINATION DATA SHEET Alaska Region
See ERDC/EL TR-07-24; the proponent agency is CECW-CO-R
OMB Control #: 0710-xxxx, Exp: Pending
Requirement Control Symbol EXEMPT:
(Authority: AR 335-15, paragraph 5-2a)
20% of total cover:50% of total cover:
0
749
0
235
1Indicators of hydric soil and wetland hydrology must
be present, unless disturbed or problematic.
Hydrophytic Vegetation Indicators:
101
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
VEGETATION Continued Sampling Point:
5.
6.
7.
8.
9.
10.
11.
12.
50% of total cover: 20% of total cover:
7.
8.
9.
10.
11.
12.
13.
14.
50% of total cover: 20% of total cover:
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
50% of total cover: 20% of total cover:
16 7
101 41
Remarks:
11
2 =Total Cover
201 =Total Cover
Herb Stratum
No FAC
32 =Total Cover
Sapling/Shrub Stratum
Cornus suecica 1
Use scientific names of plants.PF-22
Tree Stratum
Absolute
% Cover
Dominant
Species?
Indicator
Status
Herb All herbaceous (non-woody) plants, regardless
of size.
Definitions of Vegetation Strata:
Sapling/Shrub Woody plants less than 3 in. DBH,
regardless of height.
Tree Woody plants 3 in. (7.6 cm) or more in diameter
at breast height (DBH), regardless of height.
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
Sampling Point:
% %
Type1 Loc2
100
100
100
100
2Location: PL=Pore Lining, M=Matrix.
Type:
Depth (inches):Hydric Soil Present? Yes No X
Primary Indicators (any one indicator is sufficient)
N
Surface Water Present? Yes X
Water Table Present? Yes X
Saturation Present? Yes X Wetland Hydrology Present? Yes No X
Redox Depressions (F8)
Dry-Season Water Table (C2)
Other (Explain in Remarks)
Wetland Hydrology Indicators:
Water-Stained Leaves (B9)
Drainage Patterns (B10)
Restrictive Layer (if observed):
N/A
HYDROLOGY
Secondary Indicators (2 or more required)
Remarks:
Iron Deposits (B5)
Surface Soil Cracks (B6)
Shallow Aquitard (D3)
Microtopographic Relief (D4)
FAC-Neutral Test (D5)
Algal Mat or Crust (B4)
Hydric Soil Indicators: Indicators for Problematic Hydric Soils
3:
Histosol or Histel (A1)
Histic Epipedon (A2)
Depleted Below Dark Surface (A11)
Depleted Matrix (F3)
Redox Dark Surface (F6)
Alaska Color Change (TA4)4
Alaska Alpine Swales (TA5)
Alaska Redox With 2.5Y Hue
Alaska Gleyed Without Hue 5Y or Redder
Underlying Layer
Other (Explain in Remarks)
Depleted Dark Surface (F7)
Red Parent Material (F21)
4Give details of color change in Remarks.
and an appropriate landscape position must be present unless disturbed or problematic.
3One indicator of hydrophytic vegetation, one primary indicator of wetland hydrology,
Hydrogen Sulfide (A4)
Alaska Gleyed (A13)
Thick Dark Surface (A12)
Alaska Redox (A14)
Oxidized Rhizospheres along Living Roots (C3)
Presence of Reduced Iron (C4)
Salt Deposits (C5)
Stunted or Stressed Plants (D1)
Geomorphic Position (D2)
Surface Water (A1)
High Water Table (A2)
Saturation (A3)
Water Marks (B1)
Sediment Deposits (B2)
Drift Deposits (B3)
Inundation Visible on Aerial Imagery (B7)
Sparsely Vegetated Concave Surface (B8)
Marl Deposits (B15)
Hydrogen Sulfide Odor (C1)
PF-22SOIL
Loamy sand W/ash
Burnt peat
Loamy sand
Loamy sand
Remarks
0-3
Color (moist)
Depth
(inches)
Redox Features
Sandy
Loamy/Clayey
Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.)
3-6
13-20
11-13 5YR 3/3
Texture
1Type: C=Concentration, D=Depletion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains.
6-11 Sandy
Peat
Loamy/Clayey
2.5YR 2.5/2
Matrix
Color (moist)
Black Histic (A3)
10YR 3/4
2.5Y 5/2
Very Shallow Dark Surface (F22)
Alaska Gleyed Pores (A15)
Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available:
Remarks:
Field Observations:
(includes capillary fringe)
No
No
No
Depth (inches):
Depth (inches):
Depth (inches):
ENG FORM 6116-SG, JUL 2018 Alaska Version 2.0
INITIAL STUDY REPORT
ATTACHMENT L: CARIBOU POPULATION EVALUATION
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Caribou Population Evaluation
FERC No. 14873 Initial Study Report – Attachment L
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
1.1 Transmission Line ................................................................................................... 1
1.2 Study Plan............................................................................................................... 2
1.3 Mulchatna Caribou Herd......................................................................................... 3
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 4
3.0 STUDY AREA................................................................................................................... 5
4.0 METHODOLOGY ............................................................................................................. 6
5.0 RESULTS ........................................................................................................................... 6
5.1 Abundance Trends .................................................................................................. 6
5.2 Distribution ............................................................................................................. 9
5.3 Reproduction and Growth ..................................................................................... 11
5.4 Foraging Behavior ................................................................................................ 12
5.5 Population Demographics..................................................................................... 12
5.6 Potential Impacts from the Proposed Project ........................................................ 15
5.6.1 Impacts on Habitat.................................................................................... 15
5.6.2 Behavioral and Physiological Responses.................................................. 19
5.6.3 Predation ................................................................................................... 21
5.6.4 Increased Anthropogenic Activities.......................................................... 22
6.0 DISCUSSION AND FINDINGS...................................................................................... 22
6.1 Recommendations ................................................................................................. 23
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 24
7.1 Variance................................................................................................................ 24
7.2 Modifications........................................................................................................ 24
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 24
9.0 STUDY-SPECIFIC CONSULTATION ........................................................................... 24
10.0 REFERENCES ................................................................................................................. 26
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LIST OF FIGURES
Figure 1-1. Alaska Caribou Herds. Number 17 represents the Mulchatna Caribou Herd
(ADFG 2023a).........................................................................................................4
Figure 3-1. The Nuyakuk River Hydroelectric Project area within Game Management
Units (GMUs) 17B, 17C and 9B. The Project facility is within GMU 17B
and the transmission line extends into 17C and 9B. ................................................5
Figure 5-1. Population estimates for the Mulchatna Caribou Herd from 1974-2022
(Woolington 2011; Barten and Watine 2020; ADFG 2023b)..................................7
Figure 5-2. Bull-to-cow ratios of east segment (square), the west segment (diamond) and
the combined two segments (solid triangle) for the Mulchatna Caribou Herd
from the October composition surveys for 2012-2020 (ADFG 2023b). .................8
Figure 5-3. The Mulchatna Caribou Herd fall composition survey data of calf-to-cow ratio
for the east segment (square), the west segment (diamond) and the
combined two segments (solid triangle) from 2012-2020 (ADFG 2023b)..............9
Figure 5-4. Historical range (dark gray line) of the Mulchatna Caribou Herd (ADFG
2023b). Historical data provided by ADFG Division of Wildlife
Conservation. .........................................................................................................10
Figure 5-5. The Mulchatna Caribou Herd range from 2021-2022 (Demma and Sattler 2022;
ADFG 2023b). Seasonal data provided by ADFG Division of Wildlife. ..............11
Figure 5-6. Mulchatna Caribou Herd calf mortality (< 2 weeks old) from 2012 to 2021 for
the east calving ground (ADFG 2023b). ................................................................13
Figure 5-7. Mulchatna Caribou Herd calf mortality (< 2 weeks old) from 2012 to 2021 for
the west calving ground (ADFG 2023b). ...............................................................14
Figure 5-8. Mulchatna Caribou Herd population estimates compared to known MCH
harvests from 1974-2016 (Van Lanen et al. 2018). ...............................................15
Figure 5-9. The proposed transmission line transects the MCH east segment’s summer and
winter ranges. .........................................................................................................17
Figure 5-10. The proposed transmission line (red) with a 2.5 km (magenta dash line) and 4
km (magenta line) buffer. A 2.5 km (turquoise dashed line) and 4 km
(turquoise line) buffer was also placed around the existing transmission
lines. .......................................................................................................................19
LIST OF TABLES
Table 1-1. Approximate length and area of the proposed transmission line. ..................................2
Table 1-2. Approximate number and area of poles or towers of the proposed transmission
line............................................................................................................................2
Table 9-1. Summary of consultation with agencies (date and meeting description). ....................24
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ACRONYMS AND ABBREVIATIONS
ac acre
ADFG Alaska Department of Fish and Game
ATV all-terrain vehicles
Commission Federal Energy Regulatory Commission
Cooperative Nushagak Electric and Telephone Cooperative
FERC Federal Energy Regulatory Commission
ft foot
GIS Geographic Information System
GMU Game Management Unit
IM Intensive Management
km kilometer
km2 square kilometer
kV kilovolt
MCH Mulchatna Caribou Herd
mi mile
mi2 square mile
MLP&A MLP & Associates
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
S&I Survey and Inventory
USFWS U.S. Fish and Wildlife Service
USR Updated Study Report
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1.0 STUDY PLAN INTRODUCTION
1.1 Transmission Line
The transmission line design, routing, and alignment for the proposed Nuyakuk River
Hydroelectric Project (Project) is preliminary and in the conceptual design phased of the Project.
Information gathered from baseline studies (e.g., cultural, environmental, and biological surveys)
will be used to refine the design of the transmission line. For the purposes of the conceptual
design, the following describes the supplementary design criteria and construction methodology.
The present transmission intertie concept consists of 135 miles (mi) of new transmission line,
utilizing 34.5 kilovolts (kV) insulated steel tower and steel pole construction or a combination of
the two distributed over the transmission corridor. The proposed transmission line routing right-
of-way consists of roughly 1,227 acres (ac), which includes a 75 foot (ft) wide swath along the
full line corridor (Table 1-1). No substations or intermediate switching stations are expected
along the route at this time.
Spans between towers or poles along the corridor may range from 200 ft to 800 ft in length.
Using an average of 400 ft spans, this requires roughly 1,780 towers or poles in total (Table 1-2).
The actual construction details, tower or pole quantities, and routing will be determined in part
on the topography along the route, as well as requirements from cultural, environmental, and
biological surveys. The goal is to route the transmission line, where possible, away from
wetlands and along higher terrain and ridgelines.
The height of the poles will be dependent on the span and size of the conductor but will likely
range from 100-150 ft above the ground and span above the maximum canopy height if passing
over forested areas.
The typical right-of-way for the line configuration anticipated will require an average 75 ft width
along and under the transmission corridors. The planned design and routing will work to
eliminate any need for right-of-way clearing for both construction and ongoing maintenance.
This means land disturbance between towers/poles will likely not be necessary. It is anticipated
that construction and maintenance of the line will utilize aerial support (e.g., helicopters and
planes) and not require road access. Construction at each tower or pole will be self-contained at
that site using helicopter delivery of material, equipment, and personnel. It is anticipated a radius
of 75 ft around the tower or pole will be needed for construction activity, or approximately 0.4 ac
per pole. It is expected that ongoing maintenance will only require space for aerial dropping-off
or picking-up line personnel on an annual or longer periodic basis for inspection and potential
repairs.
The two types of site construction anticipated will be for a steel tower structure and for steel
poles. The decision on when and where a tower versus a pole will be used depends on the routing
and terrain. Steel towers require construction of a concrete anchorage system secured preferably
to bedrock or with deep anchors or pile foundations. Installation of steel poles will require
auguring holes and constructing a concrete pillar type foundation. The use of steel towers and
poles should eliminate the need for guy wiring extending past or outside the right-of-way
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corridor. Of concern will be upheaval of towers and pole in areas under permafrost conditions.
Extra care in design and construction will be required to prevent upheaval in locations where
frozen ground conditions exist along the proposed alignment.
Simple design features, such as conductor size and type of connectors used, will be employed to
minimize corona along the transmission line and at the tower or pole locations. Corona occurs on
all types of transmission lines but becomes more noticeable at higher voltages (i.e., 230 kV and
higher). However, in this application, corona will not be of concern given the relatively low
transmission operating voltage.
Construction duration will be dependent on a number of factors including the number of crews
working on the Project, weather impacts, and length of the construction season. Based on an
assumed construction window of 6 months per year, it is anticipated that the proposed
transmission corridor will take 3 to 4 years to construct.
Table 1-1. Approximate length and area of the proposed transmission line.
Length
(mi; kilometer [km])
Acres
(ac)
Square Kilometer
(km2)
Square Mile
(mi2)
Proposed
Transmission Line 135 (~217) 1,227 ~5 ~2
10.4 ac per Pole or Tower
Table 1-2. Approximate number and area of poles or towers of the proposed transmission line.
Number Acres (ac) per
Pole or Tower
Total Acre
(ac)
Total Square
Kilometers (km2)
Total Square
Miles (mi2)
Poles or Towers ~1,780 0.4 ~712 ~2.88 ~1.11
1.2 Study Plan
MLP & Associates (MLP&A) was contracted by McMillen for 2023-2024 Nushagak Electric
and Telephone Cooperative (Cooperative) Project Revised Study Plan (RSP) support. The
Cooperative is currently evaluating the potential for constructing a hydroelectric facility on the
Nuyakuk River to supply nearby villages with electricity. As part of the Federal Energy
Regulatory Commission (FERC) licensing process, a suite of terrestrial studies have been
included in the overall feasibility assessment. MLP&A assisted the Cooperative with the
proposed terrestrial resource studies including the caribou population evaluation described in this
report.
The Cooperative proposed to conduct a study to evaluate caribou data from the Alaska
Department of Fish and Game’s (ADFG) Division of Wildlife Conservation ongoing Mulchatna
Caribou Herd (MCH) Survey and Inventory (S&I) program (Barten and Watine 2020). The
Cooperative initiated preliminary discussion with ADFG to establish collaboration and
mechanisms for data sharing. ADFG manages an expansive caribou S&I program for the MCH
and collects data on an annual basis to document migration, productivity, health, population size
and composition, and calf survival. ADFG expressed a willingness to share the data from their
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ongoing study with the Cooperative for the purposes of conducting an impact assessment related
to Project development and operations. The Cooperative proposed to analyze ADFG’s dataset to
evaluate potential impacts to caribou as a result of the proposed Project.
In addition to working with ADFG, MLP&A investigated and evaluated impacts on caribou from
human-made linear features (e.g., transmission lines previously constructed) through a literature
review. Studies evaluating impacts and documenting the effects on caribou from similar projects
were examined and incorporated into this study to improve the understanding of the potential
impacts on the MCH from the proposed Project.
1.3 Mulchatna Caribou Herd
Caribou are a circumpolar species found in the Arctic and subarctic regions of the world.
Caribou are known as reindeer in Europe; however, in Alaska and Canada, only semi-
domesticated caribou are considered reindeer. Caribou and reindeer are classified as the same
species and include seven subspecies: barren ground (Randifer tarandus granti), Svalbard (R. t.
platyrhynchus), European (R. t. tarandus), Finnish forest reindeer (R. t. fennicus), Greenland
(R.t. groenlandicus), woodland (R. t. caribou), and Peary (R. t. pearyi). Barren ground caribou
make up the 31 caribou populations or herds in Alaska (Figure 1-1), with one exception, the
woodland Chisana herd that migrates between Canada and Southcentral Alaska. Traditionally, a
group of caribou using distinct calving areas separate from other caribou are considered a herd
(Skoog 1968; Hinkes et al. 2005; ADFG 2023a). However, there is an ongoing discussion that
metapopulation, smaller herds joining the larger herd, is a better long-term description for
caribou ecology (Hinkes et al. 2005). For this study, groups of caribou will be referred to as
herds. The MCH (barren ground) is found in the Project area.
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Figure 1-1. Alaska Caribou Herds. Number 17 represents the Mulchatna Caribou Herd (ADFG
2023a).
2.0 STUDY GOALS AND OBJECTIVES
As established in the RSP (Section 4.3.2), the overall goals of the study are to evaluate any
potential impacts of Project development to the MCH within the study area (Section 3.0). ADFG
has divided the State into geographical regions called Game Management Units or GMUs as a
wildlife management tool. Potential impacts were evaluated within GMU 17B, 17C and 9B as a
result of the proposed Project. GMU 9B was included in the study area because the proposed
transmission line extends into GMU 9B where it connects with the village of Levelock. Study
objectives include:
Evaluate the MCH population status and trends, including population size, population
composition, and breeding trends within GMU 17B, 17C and 9B.
Evaluate caribou health within GMU 17B, 17C and 9B, including body condition, calf
survival, and mortality rates.
Evaluate caribou habitat assessment within GMU 17B, 17 C and 9B, and by monitoring
the condition and productivity of captured female caribou.
Evaluate MCH land use within GMU 17B, 17C and 9B, including migration corridors,
calving areas, and foraging patterns.
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3.0 STUDY AREA
The study area encompassed the entire proposed FERC Project boundary and surrounding area
within GMUs 17B, 17C and 9B and includes approximately 63,500 square kilometers (km2;
~24,500 square miles [mi
2]; Figure 3-1). The proposed Project boundary falls within GMUs 17B,
17C and 9B. The proposed Project facilities are located within GMU 17B, and proposed
transmission lines extend into GMU 17C and 9B.
Figure 3-1. The Nuyakuk River Hydroelectric Project area within Game Management Units
(GMUs) 17B, 17C and 9B. The Project facility is within GMU 17B and the transmission line
extends into 17C and 9B.
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4.0 METHODOLOGY
To evaluate potential impacts on the MCH from the proposed Project, a literature review was
conducted. The literature review was based on peer-reviewed and gray literature found through
Google Scholar, Researchgate and agency websites. Keywords searched included linear feature,
power line, or transmission line; caribou, reindeer, or Rangifer; and Mulchatna caribou herd.
Literature was then scanned for relevant references not found in the search. Once itemized, the
literature sources were reviewed and incorporated into the impacts analysis for the study.
Correspondence with agencies was also incorporated into the analysis.
ADFG reports on the MCH were reviewed. Data within the reports were extracted and then
incorporated into the impacts analysis via graphs, tables, and maps. ADFG provided geographic
information systems (GIS) shapefiles from the S&I data set on the historical and seasonal
distribution (2020-2022) of the MCH. The shapefiles were then uploaded into Esri’s ArcGIS
software. The facility location, transmission line alignments, and potential areas of indirect
impact were plotted to aid in impacts analysis. Maps were then created and exported into JPEG
format.
5.0 RESULTS
5.1 Abundance Trends
Caribou populations naturally fluctuate over long (i.e., decades) and short time scales (i.e.,
annually) depending on environmental factors such as foraging resources, competition for
resources, winter severity, predation, disease, emigration as well as human factors such as
hunting (Skoog 1968; Hinkes et al. 2005; Van Lanen et al. 2018). Before 1900, caribou were
likely the most abundant large terrestrial mammal in southwest Alaska (Van Lanen et al. 2018).
Russians documented the presence of caribou in the area during the early 1800s, noticing a peak
in the caribou population in the 1860s and then a decline in the population in the 1870s, which
continued until the mid-1900s (Skoog 1968; Barten and Watine 2020). In 1970, the MCH was
estimated at around 5,000 individuals. The population increased to 37,000 individuals by 1985,
peaking at approximately 200,000 individuals in the mid-1990s before declining (Figure 5-1;
Woolington 2011; Barten and Watine 2020; Van Lanen et al. 2018; ADFG 2023). The most
recently published 5-year regulatory period, 2012-2016, estimated the MCH population at 27,242
individuals in 2016 (Barten and Watine 2020). In 2019 and 2022, the MCH was estimated at
13,448 and 12,112, respectively (ADFG 2020; ADFG 2023b). The 2022 estimate was
subdivided further based on a divergence in calving ground and habitat fidelity between two
segments of the MCH. The 2022 estimates were 6,242 for the east segment, which calve in the
upper Mulchatna River area, and 5,870 for the west segment, which calve north of Nuyakuk and
Tikchik lakes (see Section 5.2 Distribution for discussion of the east and west segments; ADFG
2023b).
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Figure 5-1. Population estimates for the Mulchatna Caribou Herd from 1974-2022 (Woolington
2011; Barten and Watine 2020; ADFG 2023b).
State management objectives are to maintain a population of 30,000 – 80,000 individuals with a
bull-to-cow ratio of 35:100 and a calf-to-cow ratio of 30:100 (Barten and Watine 2020; ADFG
2023c). Currently, the MCH does not meet the population management objective of 30,000-
80,000 individuals. The trends in bull-to-cow and the calf-to-cow ratios are variable from year to
year (ADFG 2023c). Figure 5-2 and Figure 5-3 show the bull-to-cow and calf-to-cow ratios from
2012-2020, respectively, for the west segment, east segment and the combination of the two
(ADFG 2023b). In 2022, the calf-to-cow ratios were 26:100 and 31:100 for the west and east
segments, respectively (ADFG 2023c). The bull-to-cow ratios were 32:100 and 44:100 for the
west and east segments, respectively (ADFG 2023c).
0
50,000
100,000
150,000
200,000
250,000
No. CaribouYear
Abundance Estimate
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Figure 5-2. Bull-to-cow ratios of east segment (square), the west segment (diamond) and the
combined two segments (solid triangle) for the Mulchatna Caribou Herd from the October
composition surveys for 2012-2020 (ADFG 2023b).
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Figure 5-3. The Mulchatna Caribou Herd fall composition survey data of calf-to-cow ratio for
the east segment (square), the west segment (diamond) and the combined two segments (solid
triangle) from 2012-2020 (ADFG 2023b).
5.2 Distribution
The range, movement and seasonal distribution of the MCH substantially changed with an
increase in population (Hinkes et al. 2005). The MCH range expanded when the population
peaked in the 1990s, extending to approximately 70,000 km2 (~27,000 square miles [mi2; Hinkes
et al. 2005). The MCH range extended west into GMU 18, north into 19A&B, south to 17A&C
and east into 9A&B (Figure 5-4). However, the range contracted with the decline in population
in the 1990s (Hinkes et al. 2005; Van Lanen et al. 2018; Barten and Watine 2020; ADFG 2023b).
With the decline in population and a contraction of range, the herd separated into two segments,
the west and east segments (ADFG 2023b). The west segment, or Unit 18 population, spends fall
and winter in Unit 18, between the Kilbuck and Eek Mountain ranges and the Kuskokwim River,
then migrates late winter early spring into the western Unit 17B&C, north of Nuyakuk and
Tikchik lakes, to calve, then returns to Unit 18 mid-summer (Figure 5-4; Figure 5-5). The east
segment, or Unit 17 population, spends fall and winter in eastern Unit 9B, 17B&C, and 19A&B,
in the Nushagak, Mulchatna, Kvichak, and upper South Fork of Hololitna river drainages. The
east segment typically remains in those units during spring, calving in the upper Mulchatna River
area (Figure 5-4; Figure 5-5; Demma and Sattler 2022; ADFG 2023b). In general, there is
seasonal spatial segregation between the two segments; however, the seasonal ranges do overlap
occasionally in some areas, such as the upper Tikchik River basin (north of the project area) in
the western Unit 17B (Figure 5-4; Figure 5-5). Additionally, some individuals have been
observed switching between segments (ADFG 2023b). This study, however, focuses on MCH
within GMUs 17B, 17C and 9B, where the proposed Project would occur.
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Figure 5-4. Historical range (dark gray line) of the Mulchatna Caribou Herd (ADFG 2023b).
Historical data provided by ADFG Division of Wildlife Conservation.
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Figure 5-5. The Mulchatna Caribou Herd range from 2021-2022 (Demma and Sattler 2022;
ADFG 2023b). Seasonal data provided by ADFG Division of Wildlife.
5.3 Reproduction and Growth
The rutting season for caribou in Alaska is from September-October. Male caribou control and
defend an area around them and the females within that area, which is different from other
species within the deer family that defend a harem of females. Females become reproductive
around 2 years of age and birth one calf seasonally. The gestation period is approximately 230
days. Most female caribou in a herd will give birth within a short period of time during late May
to June. After calving, caribou gather in large post-calving aggregations to avoid predation and
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insects. Females wean their young by September. Once insect numbers decline in August, they
scatter to forage, until rutting begins (Skoog 1968; ADFG 2023a).
5.4 Foraging Behavior
Caribou eat a variety of food resources and their diet is based on seasonal changes in vegetation
(Skoog 1968). In the summer (May-September) they forage on willow leaves, sedges, flowering
tundra plants and mushrooms. They switch to lichens, dried sedges and small shrubs in
September for the winter (ADFG 2023a). The ability to forage on large quantities of lichen is a
unique adaptation for this species of ungulate. Their migration patterns are highly linked to
forage availability (Skoog 1968).
5.5 Population Demographics
Environmental factors such as foraging resources, competition for resources, winter severity,
predation, disease, emigration as well as human factors such as hunting contribute to the
fluctuation in the MCH population size (Skoog 1968; Hinkes et al. 2005; Van Lanen et al. 2018).
The large growth in population until the 1990s is likely attributed to a series of mild winters, low
predation rates, and the ability of the MCH to expand into large amounts of available, unutilized
habitat (Woolington 2011). Additionally, from the 1970s until the 1990s, annual harvest rates
were less than 5% of the population (Woolington 2011). As the population increased, their need
for additional food resources increased, likely resulting in an expansion in range (Hinkes et al.
2005; Van Lanen et al. 2018). Over time, as the population continued to grow, overgrazing may
have occurred potentially resulting in a lack of important food resources (Van Lanen et al. 2018).
Important food resources, such as lichen, can take up to 50 years to recover (Mallory and Boyce
2018) affecting the ability of the herd to maintain peak population levels.
Lacking important food resources can lead to nutritional limitations (Demma and Sattler 2022;
ADFG 2023c). Nutritional limitations can affect overall body condition, reproduction and
susceptibility to disease. From 2020 to 2022, MCH lactating females were described as thin and
had significantly less body fat than non-lactating females showing moderate nutritional
limitations (Demma and Sattler 2022). Moderate nutritional limitations can result in depressed
pregnancy rates, slow juvenile growth and increased winter mortality (Cook et al. 2004; Gunn
and Nixon 2008; Cook et al. 2021a; Cook et al. 2021b).
Nutritional limitations can also increase susceptibility to disease. Diseases, such as hoofrot and
brucellosis, have been detected in the MCH as early as the 1990s (Van Lanen et al. 2018; ADFG
2023d; ADFG 2023e). Hoofrot affects the area directly above the hoof, creating abscesses that
can cause lameness in caribou (ADFG 2023d). Brucellosis has recently been observed in the
MCH (Van Lanen et al. 2018; Demma and Sattler 2022; ADFG 2023e). Brucellosis causes joint
inflammation and lameness, late term abortions, retained placentas, weak calves and reduced
adult survival (Demma and Sattler 2022). The disease was observed in both the east and west
segments of the MCH; however, it was more prevalent in the west segment (Demma and Sattler
2022).
Changing vegetation communities across alpine tundra is taking place likely due to climate
change (Mekonnen et al. 2021), affecting food availability for caribou (Demma and Sattler 2022)
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and interspecific competition for habitat 1. The change in vegetation includes the expansion of
shrubs, or shrubification, which likely out-compete non-vascular vegetation such as lichen
(Mekonnen et al. 2021), an important food resource for caribou. A reduction in important food
resources can then affect the overall body condition and survival rates of caribou (Demma and
Sattler 2022). Shrubification also yields increased moose (Alces alces) habitat and moose
moving into habitat not traditionally used by the species 2. Caribou have been observed
separating themselves from moose as a predator avoidance strategy (Metsaranta et al. 2001),
potentially displacing caribou from foraging habitat.
Predation on caribou fluctuates with the caribou herd’s change in population abundance. Caribou
became an abundant and reliable food source for bears and wolves as the MCH population
increased (Griffith et al. 2002; Woolington 2011; Van Lanen et al. 2018). As overcrowding may
have occurred, and habitat quality and caribou health declined, the MCH became more
susceptible to predation (Griffith et al. 2002; Woolington 2011; Van Lanen et al. 2018).
Predation is likely the prominent cause in calf mortality for the MCH affecting the calves within
first two weeks of life (Figure 5-6; Figure 5-7). Demma and Sattler (2022) observed
approximately 88% of calf mortality during the survey period was due to predation.
Figure 5-6. Mulchatna Caribou Herd calf mortality (< 2 weeks old) from 2012 to 2021 for the
east calving ground (ADFG 2023b).
1 Lindsey Kendall (MLP&A) personal communication with Andy Aderman (USFWS), April 10, 2023.
2 Lindsey Kendall (MLP&A) personal communication with Andy Aderman (USFWS), April 10, 2023.
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Figure 5-7. Mulchatna Caribou Herd calf mortality (< 2 weeks old) from 2012 to 2021 for the
west calving ground (ADFG 2023b).
Hunting may have also contributed to the decline in the MCH population. MCH population
estimates compared to known MCH harvests from 1974-2016 using permit return data show that
harvest levels and hunter reporting activity correspond to the MCH population trends (Figure
5-8; Van Lanen et al. 2018). Van Lanen et al. (2018) discussed overhunting by non-locals as a
cause in decline. Currently, local residents mostly harvest caribou from the MCH (i.e., people
that live within the herd’s range, mostly from Unit 18) and restrictions on the number of animals
harvested have been placed (ADFG 2023c). Illegal harvest is another potential factor in the
decline in population; however, it is unknown how many caribou have been illegally taken
(ADFG 2023c).
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Figure 5-8. Mulchatna Caribou Herd population estimates compared to known MCH harvests
from 1974-2016 (Van Lanen et al. 2018).
A combination of factors such as nutritional limitations, disease, predation and human-related
causes of mortality likely limit the recovery of the MCH (ADFG 2023b). Long-term studies need
to occur to better understand the dynamics of the MCH growth and decline (Hinkes et al. 2005).
5.6 Potential Impacts from the Proposed Project
The transmission line for the proposed Project will likely have the most impact on the MCH.
Impacts on the MCH from the proposed transmission line are ecologically complex and not well
understood 3; however, impacts to the MCH can be evaluated based on other human-made linear
features including transmission lines constructed within caribou and reindeer habitat in different
locations throughout the northern hemisphere. Potential impacts on the MCH associated with the
proposed transmission line may include 1) impacts on habitat (e.g., direct loss in habitat and
barrier effects), 2) behavioral (e.g., avoidance, displacement, or abandonment from important
habitat) and physiological responses (e.g., increased stress hormones), 3) increased predation,
and 4) increased anthropogenic activity.
5.6.1 Impacts on Habitat
5.6.1.1 Direct Habitat Loss
The direct loss of habitat for the MCH may result from the Project footprint of the proposed
Project, including the Project facility and transmission line, and would occur with the installation
of the proposed Project. Direct habitat loss could mean a potential loss of important habitat, such
as calving, foraging, winter and summer habitat. Direct habitat loss from the proposed Project
footprint would not likely have a substantial impact on the MCH because the Project footprint
area (10.4 km2 [~ 4 mi2]) is relatively small, less than 1 %, compared to the overall range of the
3 Lindsey Kendall (MLP&A) personal communication with Manny Eichholz (ADFG), August 30, 2023.
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MCH (~70,000 km2 [~27,000 mi
2]; Johnson et al. 2020). Therefore, the direct loss of habitat
from the proposed Project footprint would likely have a low impact on the MCH.
Although the proposed Project footprint may not result in the direct loss of substantial amounts
of habitat for the MCH, the proposed Project footprint may directly affect the MCH distribution
and movement by transecting important habitat. The proposed Project footprint does not overlap
with the MCH west segment’s current range; however, the proposed Project footprint does
overlap with the MCH east segment’s range (Figure 5-9). Both the east and west segments’
calving areas are not within the Project area (Figure 5-9). The transmission line footprint
transects portions of the east segment’s summer and winter ranges, and likely transects the east
segment’s migratory routes (Pritcher 1987). The transmission line footprint also transects the
MCH historical range (Figure 5-4). By transecting the MCH range, caribou may be forced to
change their movement patterns resulting in a change in distribution. However, distribution and
movement patterns of caribou are variable and depend on environmental factors, including
available foraging habitat, weather conditions, and terrain (Skoog 1968; Bergerud et al. 1984);
therefore, the amount and arrangement of the MCH range transected by the transmission lines
may change over time.
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Figure 5-9. The proposed transmission line transects the MCH east segment’s summer and
winter ranges.
5.6.1.2 Barrier and Avoidance Effect
There is ongoing discourse within the scientific literature as to whether or not, and to what
degree, transmission lines in operation present a barrier to movement or otherwise disturb
caribou or reindeer (Reimers et al. 2020). Numerous variables seem to influence whether a
specific study on the matter finds conclusive evidence supporting or denying barrier effects from
transmission lines: population demographics, terrain, habitat quality, habitat type, range size,
existing infrastructure, accompanying development, herd domestication history, study scale,
cumulative effects, line voltage, tower/pole type and more.
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Recent studies are in modest agreement that transmission lines on their own are not a substantial
barrier to wild reindeer movements or use of an area (Reimers et al. 2020), especially over
timeframes exceeding 5-10 years. Because there is a lack of available data about the MCH
response to infrastructure, including the transmission lines constructed between Ekwok and New
Stuyahok in 2017, this discussion considers barrier effects at two levels: (1) strong barrier effects
and (2) limited barrier effects.
1. Strong barrier effects would occur when caribou avoid transmission lines within
approximately 2.5 km to 4 km during operation, and therefore, the transmission line
impedes caribou movement across the corridors. This level of effect was observed by
Vistnes and Nellemann (2001, via Bartzke et al., 2014), Nellemann et al. (2001),
Mahoney and Schaefer (2002) and Nellemann et al. (2003).
2. In the limited barrier effects case, caribou would behave as if the transmission lines are
not there, or with minimal change in behavior in the long term (>5-10 years), which is
supported by Reimers et al. (2020).
If strong barrier effects are assumed, based on the avoidance distances of 2.5 km to 4 km, an
effective loss of approximately 300 km
2 to 450 km2 (~115 mi2 to 175 mi2), respectively, would
occur in the MCH east segment summer habitat and approximately 500 km2 to 780 km2 (~190
mi2 to 300 mi
2), respectively, in the MCH east segment winter habitat (Figure 5-10). Movements
across the transmission line corridors would be limited, effectively cutting the MCH east
segment caribou off from summer range in the Wood Tikchik Mountains and south of Kemuk
Mountain. The same would be true for existing winter range south of Kemuk Mountain to
Ekwok, and south and west of Levelock. Traditional migration routes throughout the lower
Nushagak River Basin would be disrupted long-term.
If barrier effects are limited, these impacts would be considered negligible over the long-term,
and potentially in the short-term as well. It is likely that any temporary disruption of movements
and avoidance of the proposed transmission lines would be overcome by a short-term shift in
seasonal distribution, followed by eventual reoccupation of the Project area.
As discussed above, recent discourse on how strong of a barrier transmission lines present when
not associated with roads or large increases in anthropogenic activity has moved away from the
strong barrier effect described by earlier research. Reimers et al. (2020) argued that there are a
few reasons to discount those findings: recent research utilized before-after-impact control
studies, whereas earlier research did not; a pre-supposition based on public opinion that
transmission lines were a barrier to caribou may have influenced earlier study design and
interpretation of results; and the evidence and rationale for the mechanism of disturbance (e.g.,
visual, auditory, olfactory) is not particularly compelling.
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Figure 5-10. The proposed transmission line (red) with a 2.5 km (magenta dash line) and 4 km
(magenta line) buffer. A 2.5 km (turquoise dashed line) and 4 km (turquoise line) buffer was also
placed around the existing transmission lines.
5.6.2 Behavioral and Physiological Responses
5.6.2.1 Behavioral Response
The MCH behavioral responses to the proposed transmission line may include avoidance,
displacement or abandonment of habitat. Behavioral responses may lead to temporary or
permanent loss of important habitat such as calving, winter and summer areas as well as
physiological responses (Section 5.6.2.2). Although the direct loss of habitat from the proposed
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project (Section 5.6.1.1) would likely be small, these indirect effects would likely have a larger
impact on caribou (Johnson et al. 2020).
Construction of the transmission line will likely increase human activity and noise in otherwise
undisturbed areas and may cause short-term avoidance of the area by caribou (Pritcher 1987;
Colmann 2015). Colmann et al. (2015) documented reindeer reducing the use of an area up to 6
km during the construction of a power line in Norway (Colmann et al. 2015); however, once
construction ceased, reindeer use of the area close to the power line increased. Construction of
the proposed transmission line would be temporary and occur in phases, potentially reducing
disruption on a short-term level (e.g., seasonally). Conversely, several phases of construction
over a longer period of time (e.g., years) could result in long-term effects such as avoidance,
displacement and even abandonment of the area.
Specific groups of caribou or reindeer (e.g., cows and calves) and seasonal timing may affect the
presence of caribou near transmission lines. (Wolfe et al. 2001). Cows and calves during calving
season are more disturbed in the presence of human activity (Wolfe et al. 2000; Nellemann et al.
2001) and may be more likely to avoid the transmission line than bulls and caribou during insect
harassment (Wolfe et al. 2000). Avoidance of the proposed transmission line may be temporary
if the MCH become habituated to the presence of power lines or population dynamics encourage
reoccupation of abandoned habitat (Reimers et al. 2020).
Caribou or wild reindeer may avoid powerlines because of the corona effect or corona discharge.
The corona effect or corona discharge occurs when an induced current around a conductor
exceeds the amount needed to ionize air, emitting violet-to-ultraviolet light and a crackling or
humming noise. The onset voltage for corona discharge is variable and depends on
environmental factors (Stracqualursi et al. 2021). Wild reindeer are thought to be sensitive to
ultraviolet light (Tyler et al., 2014) and can likely hear noise from coronal discharge (300-420
kV) up to 79 meters away (Flydal et al. 2003). Because of the relatively low voltage of the
proposed transmission lines (i.e., 34.5 kV), it is not expected that the corona effect would be
audible (Flydal et al. 2001 in Flydal et al. 2003) or emit enough visible or ultraviolet light to be
detected by caribou; however, to minimize impacts to the MCH from the corona effect, corona
discharge could be reduced through the engineering and design of the transmission lines.
Caribou may delay crossing or even fail to cross portions of the transmission line (Wolfe et al.
2000); however, caribou use of the “least energetic resistance response” in the natural
environment could be applied to understanding caribou responses to human-made linear features
(Skoog 1968; Bergerud et al. 1984). Caribou may travel “parallel” or “deflect” natural linear
features (e.g., lakes and rivers) in response to paths of “least energetic resistance.” Paralleling
occurs when caribou follow contours prior to crossing them to find easiest route (Skoog 1968).
Deflection occurs when caribou travel around obstructions (Bergerud et al. 1984). For instance,
caribou will seek narrow sections of rivers and lakes to cross, will travel single-file in deep snow
then spread out in unimpeded terrain, and travel along wind-blown ridgetops when valleys are
inundated with snow even though the topography its steeper (Bergerud 1984). Similar behavior
may be applied to caribou traveling parallel or deflecting human-made linear features such as the
proposed transmission line (Bergerud 1984). The placement of poles or towers may affect where
caribou cross. Longer spans between poles or towers, especially in high-quality habitat and
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migration corridors may minimize impacts by allowing caribou easier crossings; however, other
factors relating to the transmission line (e.g., the corona effect) can also inhibit caribou crossing.
Separating the effects of human development from natural variation in caribou habitat and
demography can be difficult and hard to assess (Wolfe et al. 2001).
5.6.2.2 Physiological Response
Caribou may be disturbed by the presence of transmission lines without exhibiting behavioral
responses, but instead a physiological response. Increased levels of stress hormones in response
to human activity has been documented in multiple wildlife species, including ungulates
(Arlettaz et al., 2007; Creel et al., 2002; Wasser et al., 1997). Increased heart rates in response to
human disturbance with no change in behavior have been documented in bighorn sheep
(MacArthur et al. 1979, 1982 via Bartzke et al. 2014). Chronic stress can result in a variety of
adverse physiological impacts in wildlife without any apparent changes to behavior, including
muscle loss, slowed growth, inhibited reproduction, neuron degeneration, and immune
suppression (Ashley et al. 2011). Additionally, avoiding the transmission line may increase
caribou energy expenditure (Wolfe et al. 2001), which may affect their overall body condition. It
is not clear if caribou would exhibit a stress response to transmission lines in the absence of
increased anthropogenic activity. Non-invasive monitoring methods could be implemented to
determine if the proposed infrastructure induces chronic stress in MCH caribou, and to what
extent.
5.6.3 Predation
Studies on the impacts of linear features on large mammalian predator movements and prey
interactions have generally focused on forested habitats where vegetation is clearcut, creating an
easily navigable corridor utilized by predators and avoided by prey species. Predator speed has
been shown to increase along this type of linear feature which is presumed to increase foraging
success rate (Dickie et al. 2016; Dabros et al. 2018; Dickie et al. 2020). Of particular concern
would be the creation of a corridor that would allow predators to quickly move between caribou
habitats, which could be the case for this project if clearcutting occurs. Project impacts from
vegetation removal would be avoided where possible. Clearcutting would be limited to small
pads at towers/poles and would only be necessary in portions of the alignment within forested
areas. Selective vegetation management (i.e., trimming or selective removal of tall trees) could
be implemented beneath overhead lines to prevent creating a high-speed predator corridor.
Golden eagles (Aquila chrysaetos) are the only known avian predator of the MCH, contributing
to calf mortality in most years (Barten and Watine 2020). Transmission line towers/poles are
often used by golden eagles as perches or as communal roosts, particularly in winter when
resources are scarce (Hixson et al. 2022). Although golden eagles do not winter in Alaska, some
use of towers/poles by eagles can be expected when they are present. The tundra southwest of
Koliganek is a historical calving ground for MCH (ADFG 2015; Van Lanen et al. 2018). Caribou
select calving grounds in part to minimize interactions with predators (Bergerud et al. 1984;
Gunn and Miller 1986). An increase in golden eagle occurrence due to the installation of
transmission line towers/poles could preclude use of this area by caribou for calving over the life
of the project.
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The occurrence of other raptors may also increase with the presence of towers/poles. This would
shift predator-prey dynamics in the area and has the potential to cause broad ecological effects
that are difficult to predict. For example, increased predation of small herbivores could increase
available forage for caribou, but ecosystem services provided by small herbivores, such as soil
aeration by burrowing, would likely be reduced and could have a long-term detrimental impact
on forage availability. Perch deterrents could be used to discourage eagle and other raptor use of
the transmission infrastructure.
5.6.4 Increased Anthropogenic Activities
Increased anthropogenic activities would occur during construction of the proposed transmission
line and potentially after construction. During the construction of the proposed transmission line,
the use of construction equipment, vehicles, and aircraft (e.g., fixed-winged and helicopters)
would occur in undisturbed areas. Construction activities would likely increase noise in the area
which may disturb or harass caribou adjacent to the Project area (Pritcher 1987). It is notable
that this activity would be short-term during construction of the proposed Project.
The installation of the transmission line could create a corridor between villages and increase
human access to areas previously unused (Pritcher 1987). People could access these areas using
all-terrain vehicles (ATV) and snowmachines. Increased access may result in increased hunting
(Bergerud 1984), including illegal hunting, in remotes areas (Pritcher 1987). Although the
transmission line may create a corridor, access to the corridor would likely be variable,
depending on the terrain and whether ATVs or snow machines could be maneuvered in the area.
Clearcutting is not planned for this project, which would complicate overland navigation along
corridors that pass through densely forested areas. Additionally, in winter, commuting from one
village to another on snowmachines may be more accessible and direct along the river or existing
winter trails.
6.0 DISCUSSION AND FINDINGS
Since the 1970s, the MCH has experienced fluctuations in population size and range due to
environmental factors including availability of foraging resources, competition for resources,
climate, predation, disease, as well as human factors such as hunting. The transmission line for
the proposed Project will likely have the most impact on the MCH because it would transect
portions of the MCH historical range, transect portions of the east segment’s winter and summer
ranges and would likely affect migration routes. Potential impacts on the MCH associated with
the proposed transmission line may include 1) impacts on habitat (e.g., direct loss in habitat and
barrier effects), 2) behavioral (e.g., avoidance, displacement, or abandonment from important
habitat) and physiological responses (e.g., increased stress hormones), 3) increased predation,
and 4) increased anthropogenic activity.
Direct habitat loss from the proposed Project footprint would not likely have a substantial impact
on the MCH because the Project footprint area is relatively small compared to the overall range
of the MCH; however, the transmission line could potentially create a barrier impeding caribou
crossing, which could result in the indirect loss of habitat. Conversely, caribou are known for
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navigating around natural obstructions and may apply similar tactics when navigating human-
made structures. Increased predation could occur with clearcutting the transmission line right-
of-way, creating an easily navigable corridor for predators, but clearcutting is not anticipated for
the proposed Project because of the terrain within the Project area. Anthropogenic activity is
anticipated to increase short-term during construction of the proposed Project and may increase
long-term depending on accessibility of the transmission line corridor, which may result in
caribou avoidance of the area. Determining the impacts on the MCH from the proposed Project is
complex and difficult to assess due to numerous confounding factors. Therefore, continued
investigation of the impacts on the MCH from the proposed transmission line as the Project
evolves would help to better understand the overall effects of the proposed Project.
6.1 Recommendations
Determining the impacts on the MCH from the proposed Project is challenging to evaluate. It is
anticipated that ADFG will continue to monitor the herd and it would be recommended that the
Cooperative consult and potentially collaborate with ADFG to conduct site-specific monitoring
before, during and after construction to help mitigate impacts and contribute to the understanding
of the potential effects. The following is a list of recommendations to help understand the
potential impacts on the MCH from the proposed Project. Other recommendations may be
identified through consultation with the stakeholders.
Before Construction
1. Form a working group
2. Transmission line design
a. Design a low-impact transmission line and consider high quality caribou habitat
when placing poles/towers.
b. Avoid building in calving areas.
c. Reduce the corona affect.
3. Establish a MCH Monitoring Program to be implemented during construction and
periodically during operations.
a. Develop and implement a long-term caribou monitoring study plan documenting
and evaluating the effects of the proposed Project on the MCH. The plan could
include:
i. consultation with agencies during the development and implementation of
the plan;
ii. monitoring during and after construction;
iii. incorporate ADFG S&I data (e.g., telemetry data) with field observations;
and
iv. analyze movement and distribution around transmission line.
Construction of the proposed Project
1. To mitigate the impacts of human activity on caribou during construction, implement the
following:
a. the MCH monitoring plan; and
b. timing windows depending on where the caribou are and what activity the caribou
are participating in (e.g., calving areas, seasonal migration).
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After Construction
1. Continue to periodically monitor the MCH adjacent to the proposed Project.
7.0 STUDY VARIANCES AND MODIFICATIONS
7.1 Variance
MLP&A discussed data sharing on numerous occasions with ADFG (Section 9.0). To access
ADFG’s data, an individual data sharing agreement between MLP&A and ADFG would need to
occur. No such agreement was obtained.
7.2 Modifications
GMU 9B was included in the impact analysis because the transmission line extends into 9B
when it connects to the village of Levelock. GMU 9B is within the range of the MCH.
MLP&A was able to analyze and incorporate ADFG S&I data from ADFG, Division of Wildlife
Conservation publicly available reports on the MCH. S&I data were extracted from these reports
and incorporated into the impact analysis. At this time, those reports are the best available data
for use.
MLP&A conducted a literature review to improve the understanding of potential impacts on the
MCH from the proposed Project. Studies evaluating and documenting impacts on caribou from
similar projects were examined and incorporated into the impact analysis.
8.0 STUDY STATUS AND SCHEDULE
MLP&A proposes to continue to modify the Caribou Population Evaluation report with updated
ADFG S&I data, ADFG reports and literature. The MCH is dynamic and changing on a short-
term (i.e., annually) and long-term (i.e., decades) bases; therefore, impacts to the MCH from the
proposed Project may change as the herd changes and the proposed Project evolves. If made
available, this additional data will be incorporated into the USR.
9.0 STUDY-SPECIFIC CONSULTATION
MLP&A consulted agencies during the study via meetings and correspondence (Table 1).
Table 9-1. Summary of consultation with agencies (date and meeting description).
Date Meeting Description
02/21/2023 –
02/27/2023
Email – Lindsey Kendall (MLP&A); Todd Rinaldi and John Landsiedel
(ADFG) – Request for information and schedule meeting to discuss the
Mulchatna Caribou Herd.
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02/28/2023
Zoom Meeting – Lindsey Kendall and Maria Lewis (MLP&A); Todd Rinaldi,
Manny Eichholz, John Landsiedel, Evelyn Lichwa and Renae Sattler
(ADFG) – Introductory meeting to discuss project, available caribou data
and proposed cooperation on sharing data.
03/02/2023 Email – Lindsey Kendall (MLP&A) and Renae Sattler (ADFG) Follow up to
caribou data meeting. Set up following meeting regarding potential data.
03/13/2023 Email – Lindsey Kendall (MLP&A) and Renae Sattler (ADFG) – Zoom
meeting logistics
03/13/2023 Phone/Zoom meeting – Lindsey Kendall (MLP&A) and Renae Sattler
(ADFG) – Meeting to discuss possible file formats of caribou data.
04/10/2023
Phone meeting – Lindsey Kendall (MLP&A) and Andy Aderman (USFWS)
Informational meeting. Topics included USFWS statistics and monitoring of
the MCH, observations of how caribou herds have historically responded
to similar development projects, and factors that he felt may be impacting
MCH population decline. Also discussed moose.
05/15/2023
Email – Lindsey Kendall (MLP&A); Todd Rinaldi, Manny Eichholz, John
Landsiedel, Andy Aderman, Evelyn Lichwa and Renae Sattler (ADFG)
Lindsey provided ADFG contacts with transmission line project description.
07/20/2023 –
07/25/2023
Email – Lindsey Kendall (MLP&A) and Manny Eichholz (ADFG) – setting
up meeting.
07/26/2023 Phone Meeting – Lindsey Kendall (MLP&A) and Manny Eichholz (ADFG).
Follow up meeting on the status of obtaining data on the MCH from ADFG.
07/28/2023 –
08/01/2023
Email – Lindsey Kendall (MLP&A) and Manny Eichholz (ADFG).
Coordinating on best available literature and contact information for
shapefiles.
08/28/2023
Phone meeting – Lindsey Kendall (MLP&A) and Renae Sattler (WEST Inc.,
formerly ADFG) Discussion of MCH, updated information on herd and
update on the results of her data analysis.
08/30/2023
Email – Lindsey Kendall (MLP&A) Manny Eichholz (ADFG). ADFG
comments on project and possible impacts from the project on caribou
herd as well as possible mitigation measures.
08/30/2023 Email – Lindsey Kendall (MLP&A) and Todd Rinaldi. Setting up meeting.
08/30/2023
Zoom meeting – Lindsey Kendall and Maria Lewis (MLP&A) and Todd
Rinaldi and Manny Eichholz (ADFG). MLP&A updated ADFG on study,
requested shapfiles with season and historic range data to overlay on
project area, as well as migration patterns through areas with existing
transmission lines. Todd discussed another ADFG point of contact.
09/06/2023 –
09/08/2023
Email – Lindsey Kendall (MLP&A) and Manny Eichholz (ADFG). Email
requesting and receiving shapefiles.
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10.0 REFERENCES
ADFG. 2015. Caribou Management Report of Survey-Inventory Activities, 1 July 2012-30 June
2014. Alaska Department of Fish and Game, Division of Wildlife Conservation.
ADF&G/DWC/SMR-2015-4.
ADFG. 2020. Annual Report to the Alaska Board of Game on Intensive Management of
Caribous with Wolf Predation Control in Game Management Units 9B. 17B&C, and
19A&C, the Mulchatna Caribou Herd. Division of Wildlife Conservation. February 2020.
<https://www.adfg.alaska.gov/static/applications/web/nocache/research/programs/intensi
vemanagement/pdfs/2020_mulchatna_intensive_management_annual_report.pdf3408BE
876B35553434F8C635EED23A58/2020_mulchatna_intensive_management_annual_rep
ort.pdf>. Accessed August 25, 2023.
ADFG. 2023a. Caribou species (Rangifer tarandus granti) profile. Alaska Department of Fish
and Game. <https://www.adfg.alaska.gov/index.cfm?adfg=caribou.main>. Accessed
August 18, 2023.
ADFG. 2023b. Operational Plan for Intensive Management of Caribou (Rangifer tarandus) in
Game Units 9B, 17, 18, 19A & 19B during Regulatory Years 2022-2028. Division of
Wildlife. Version 2.1, February 2023.
ADFG. 2023c. Annual Report to the Alaska Board of Game on Intensive Management of
Caribous with Wolf Predation Control in Game Management Units 9B. 17B&C, and
19A&C, the Mulchatna Caribou Herd. Division of Wildlife Conservation. February 2023.
<https://www.adfg.alaska.gov/static/applications/web/nocache/research/programs/intensi
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61C6A6807EAAD78B8167B662D2/2023_mulchatna_intensive_management_annual_re
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ADFG 2023d. Parasite and Disease. Hoofrot. Alaska Department of Fish and Game.
<https://www.adfg.alaska.gov/index.cfm?adfg=disease.general5>. Accessed September
11, 2023.
ADFG 2023e. Parasite and Disease. Brucellosis. Alaska Department of Fish and Game.
<https://www.adfg.alaska.gov/index.cfm?adfg=disease.general3>. September 11, 2023.
Arlettaz, R., P. Patthey, M. Baltic, T. Leu, M. Schaub, R. Palme and S. Jenni-Eiermann. 2007.
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Ashley, N.T., P.S. Barboza, B.J. Macbeth, D.M. Janz, M.R.L. Cattet, R.K. Booth, and S.K.
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Barten, N. L. 2015. Mulchatna herd caribou, Units 9B, 17, 18 south, 19A, and 19B. Chapter 3,
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report of survey-inventory activities 1 July 2012–30 June 2014. Alaska Department of
Fish and Game, Species Management Report ADF&G/DWC/SMR-2015-4, Juneau.
Barten, N. L., and Watine, L. N. 2020. Caribou Management Report and Plan, Game
Management Units 9A, 9B, 9C, 17A, 17B, 17C, 18, 19A, 19B: Mulchatna Caribou Herd.
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Bartzke, G. S., R. May, K. Bevanger, S. Stokke and E. RøSkaft. 2014. The effects of power lines
on ungulates and implication for power line routing and rights-of-way management.
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Bergerud, A. T., Jakimchuk, R. D., and Carruthers, D. R. 1984. The Buffalo of the North:
Caribou (Rangifer tarandus) and Human Developments. Arctic 37(1): 7-22.
Colmann, J.E., T. Bergmo, D. Tsegaye, K. Flydal, S. Eftestøl, M.S. Lilleeng and S.R. Moe.
2016. Wildlife response to infrastructure: the problem with confounding factors. Polar
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Cook, J., B.K. Johnson, R.C. Cook, R.A. Riggs, T. Delcurto, L.D. Bryant and L.L. Irwin. 2004.
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elk. Wildlife Monographs 1-61.
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Nushagak Cooperative, Inc. 30 December 2023
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INITIAL STUDY REPORT
ATTACHMENT M: SUBSISTENCE STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Subsistence Study
FERC No. 14873 Initial Study Report – Attachment M
Nushagak Cooperative, Inc. December 2023
SUBSISTENCE STUDY UPDATE
he Subsistence Study will be implemented in 2024 as specified in the Project’s
Revised Study Plan (RSP). Data gathered for the Subsistence Study will be analyzed and
reported on in the Updated Study Report (USR), along with an assessment of potential impacts
associated with Project development and operations. The USR will be filed with the Federal
Energy Regulatory Commission (FERC) no later than December 1, 2024.
INITIAL STUDY REPORT
ATTACHMENT N:
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Cultural Resource Survey
FERC No. 14873 Initial Study Report – Attachment N
Nushagak Cooperative, Inc. i December 2023
STATEMENT OF CONFIDENTIALITY
To protect fragile, vulnerable, or threatened cultural sites from disturbance, access to site-
specific information from the Alaska Heritage Resources Survey is restricted or confidential.
Distribution of portions of this report that identify the location of cultural sites is to be limited to
those with a legitimate need to know, such as appropriate personnel from Cultural Resource
Consultants LLC, Nushagak Electric & Telephone Cooperative, Inc., McMillen, Inc., and the
Office of History and Archaeology. Restricted or confidential information is withheld from
public records disclosure under state law (AS 40.25.110) and under the federal Freedom of
Information Act (PL 89-554). Information about site inventory may be restricted pursuant to AS
40.25.120(a)(4), Alaska State Parks Policy and Procedure No. 50200, the National Historic
Preservation Act (PL 89-665, 16 U.S.C. 470), and the Archaeological Resources Protection Act
(PL 96-95).
INITIAL STUDY REPORT
ATTACHMENT O: NOISE STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY AREA................................................................................................................... 1
3.0 METHODOLOGY ............................................................................................................. 3
3.1 Criteria.................................................................................................................... 3
3.1.1 Metrics ........................................................................................................ 3
3.1.2 General Construction Noise........................................................................ 3
3.1.3 Construction Blasting.................................................................................. 4
3.1.4 Operations Noise......................................................................................... 4
3.2 Human Perception / Comparison............................................................................ 4
3.3 Survey Methodology ............................................................................................... 5
3.4 Measurement Equipment ........................................................................................ 8
3.5 Weather Conditions ................................................................................................ 8
3.6 Modeling Methodology .......................................................................................... 8
3.7 Model Data and Assumptions ................................................................................. 9
3.7.1 General Construction .................................................................................. 9
3.7.2 Blasting ..................................................................................................... 10
3.7.3 Operations ................................................................................................. 10
3.7.4 Air Traffic................................................................................................. 10
4.0 MEASUREMENT RESULTS .......................................................................................... 11
4.1 Sound Level Measurements.................................................................................. 11
4.2 Results................................................................................................................... 11
4.3 Ambient Level Discussion.................................................................................... 12
5.0 NOISE IMPACT ASSESSMENT.................................................................................... 13
5.1 Ambient Model..................................................................................................... 13
5.2 Construction Noise – Typical Equipment............................................................. 13
5.3 Construction Noise – Blasting .............................................................................. 15
5.4 Normal Operation................................................................................................. 15
5.5 Aircraft Operations ............................................................................................... 17
6.0 DISCUSSION AND FINDINGS...................................................................................... 17
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 18
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 18
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9.0 STUDY-SPECIFIC CONSULTATION ........................................................................... 18
10.0 REFERENCES ................................................................................................................. 18
LIST OF FIGURES
Figure 2-1. Noise Study Area. .........................................................................................................2
Figure 3-1. Ambient Survey Sound Level Measurement Locations................................................6
Figure 3-2. Ambient Survey Location Photos .................................................................................7
Figure 5-1. Change in Sound Level due to Construction Activities over Study Area,
Daytime ..................................................................................................................14
Figure 5-2. Change in Sound Level due to Operations over Study Area, Nighttime ....................16
LIST OF TABLES
Table 3-1. Regulatory Limits for Coal Mining Blasting..................................................................4
Table 3-2. Loudness Perception as a Function of A-weighted Sound Level ...................................4
Table 3-3. Ambient Survey Sound Level Measurement Details. ....................................................7
Table 3-4. Summary of Weather Conditions...................................................................................8
Table 3-5. Construction Equipment Included in Assessment - Intake and Powerhouse .................9
Table 3-6. Sound Power Levels (Lw) for Proposed Project Equipment.........................................10
Table 4-1. Summary of Measurement Field Observations............................................................11
Table 4-2. Summary of Sound Level Measurement Results .........................................................11
Table 4-3. Summary of Sound Level Measurement Results – Baseline Levels ............................12
Table 5-1. Predicted Construction Sound Levels ..........................................................................13
Table 5-2. Summary of Noise Model Results – Normal Operation ..............................................15
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ACRONYMS AND ABBREVIATIONS
Commission Federal Energy Regulatory Commission
dB Decibel
dBA A-Weighted Decibel
EPA Environmental Protection Agency
FAA Federal Aviation Administration
FERC Federal Energy Regulatory Commission
ft foot
HUD U.S. Department of Housing and Urban Development
ISEE International Society of Explosive Engineers
ISR Initial Study Report
Ldn 24-Hour Day-Night Sound Level
Leq Equivalent Continuous Sound Level
NSA Noise Sensitive Area
NSR Noise Sensitive Receptor
Project Nuyakuk River Hydroelectric Project (P-14873)
USGS U.S. Geological Survey
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
The purpose of the noise study was to assess the existing sound levels in the Project area and
predict future sound level impacts that would occur during short-term construction and long-term
operations at areas of interest surrounding the Project location. This included collecting ambient
sound level measurements and developing several computer noise models to predict sound level
impacts during various stages of the Project.
The ambient survey plan consisted of overnight sound level measurements at four baseline
locations at Noise Sensitive Receptors (NSRs) surrounding the proposed Project area.
A computer noise model was developed using Cadna/A, a standards-based computer modeling
software package from DataKustik GmbH. Four variants were created to calculate predicted
sound level impacts during each potential phase of the Project. These phases included general
construction, construction blasting, operations, and air traffic noise analyses.
2.0 STUDY AREA
The study was conducted in the vicinity surrounding the proposed Project facilities (as currently
conceptually designed). The study area also included the area near the Royal Coachman Lodge,
which is located upriver towards Tikchik Lake (Figure 2-1).
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3.0 METHODOLOGY
3.1 Criteria
3.1.1 Metrics
There are many ways to measure and quantify sound levels. There are certain metrics that are
more appropriate for specific types of sounds depending on the duration and amplitude of the
sound.
The equivalent sound level (Leq) is a sound level having the same sound energy as the time
varying sounds over a given time period. It is essentially the average sound level over the
period. The L90 is a statistical metric that represents the sound level exceeded 90% of a given
time period. It is often used to exclude the effect of short-term transient sound levels and can be
used as the background or ambient sound level during a period.
For long-term environmental noise and land-use compatibility evaluations, many federal
agencies, including the EPA, HUD, FAA, and FERC, use the 24-hour day-night average sound
level (Ldn). The Ldn is essentially a 24-hour average sound level with a penalty of 10 decibels for
sounds during nighttime hours due to increased sensitivity to noise at night. The daytime
equivalent continuous level (Ld) is the average sound level between 7:00 AM and 10:00 PM,
while the nighttime equivalent continuous level (Ln) is the average sound level between 10:00
PM and 7:00 AM.
The short-term impulsive sound pressure wave due to blasting is typically referred to as
“overpressure” or “airblast”. For extremely short-duration impulsive sounds, such as the
overpressure wave from blasting, the Federal government uses two different metrics – the
unweighted peak sound level (LPk) and the C-weighted slow maximum sound level (LCSmax).
The LPk sound level is the highest sound level recorded by the sound level meter and doesn’t
include any time averaging or frequency weighting. The LCSmax sound level is the highest
measured one-second moving average sound level over a given time-period with C-weighting
applied. The one-second moving average (referred to in acoustics as the slow time constant) will
smooth out the measured sound levels for impulsive events by averaging the short-duration peak
with other, lower, sound levels before and after the peak. C-weighting is a frequency weighting
which discounts extremely low and high frequency sounds and mimics the response of the
human ear to very high amplitude (loud) sounds. It is commonly used while evaluating low-
frequency sound levels.
3.1.2 General Construction Noise
The Federal Energy Regulatory Commission (FERC) does not have specific noise requirements
for daytime construction activities (FERC 2017). For construction activities that occur at night,
the FERC typically limits construction noise to 48.6 dBA or an equivalent 55 dBA Ldn at any
nearby Noise Sensitive Areas (NSAs).
Nuyakuk River Hydroelectric Project Noise Study
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Nushagak Cooperative, Inc. 4 December 2023
NSAs are typically residences, houses of worship, hotels, and hospitals. NSAs can also be
locations that are “valued specifically for solitude and tranquility”. For the Intake and
Powerhouse area of the Project, the closest NSA is the Royal Coachman Lodge.
3.1.3 Construction Blasting
There are no specific regulatory limits that apply to Project blasting. For sound levels due to
blasting related to coal mining activities, the Office of Surface Mining (CFR 2017) has
maximum limits for airblast/overpressure at the location of any dwelling, public building, school,
church, etc. in order to limit potential damage to structures. These limits are summarized in
Table 3-1.
Table 3-1. Regulatory Limits for Coal Mining Blasting
Lower frequency limit of measuring system, in
Hz
(±3 dB)
Maximum level, in
dB
Corresponding Sound
Level Metric
0.1 Hz or lower - flat response 134 peak.
LPk, dB 2 Hz or lower - flat response 133 peak.
6 Hz or lower - flat response 129 peak.
C-weighted - slow response 105 peak dBC. LCSmax, dBC
Guideline levels aimed at minimizing annoyance to people exposed to repeated blast events are
provided in the Australian and New Zealand Environment Conservation Council’s (ANZECC)
Technical Basis for Guidelines to Minimize Annoyance due to Blasting Overpressure and
Ground Vibration (1990). This guideline recommends an airblast criterion of 115 dB peak for
people, but permits this level to be exceeded by 5 dB for up to 5% of all blasts in a year (i.e., a
not to be exceeded limit of 120 dB peak).
3.1.4 Operations Noise
For operational sound from regulated facilities, FERC generally prescribes a sound level limit of
55 dBA Ldn at all NSAs. FERC generally limits the allowable increase in the ambient Ldn to less
than 10 decibels.
3.2 Human Perception / Comparison
The subjective human perception of the quality of sound is typically called “loudness”. Most
people consider a change of 3-dB to be a perceptible change in loudness, a 5-dB change to be
clearly noticeable, and a 10-dB change to sound twice or half as loud (BBN 1973). Table 3-2
shows the relative loudness as a function of changes in the A-weighted sound level.
Table 3-2. Loudness Perception as a Function of A-weighted Sound Level
Description of Sound
Sound
Level,
dB(A)
Relative
Loudness
Compared to 60
dBA
Subjective Loudness for
Most People, Compared to
a Sound Level of 60 dBA
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 5 December 2023
Threshold of pain 140 256
256 times louder
Jet taking off (200-foot distance)130 128
128 times louder
Operating heavy equipment 120 64
64 times louder
Night club with music 110 32
32 times louder
Construction site 100 16
16 times louder
Boiler room 90 8 Eight times louder
Freight train (100-foot distance)80 4 Four times louder
Classroom chatter 70 2 Twice as loud
Conversation (3-foot distance)60 1 Same (Baseline condition)
Urban residence 50 1/2
Half as loud
Soft whisper (5-foot distance)40 1/4
One-quarter as loud
North rim of Grand Canyon 30 1/8 One-eight as loud
Silent study room 20 1/16 One-sixteenth as loud
Threshold of hearing (1,000 hertz) 0 1/64 One sixty-fourth as loud
Adapted from USDOL 2016
dBA = decibels on the A-weighted scale
The potential impact of the project has been evaluated by comparing the predicted future sound
levels for the proposed Project phases with the existing ambient sound levels. The ambient
sound levels are expected to vary across the Project area, due to the localized influence of noise
from the falls, water flow from the Nuyakuk River, and the variations in other natural sounds.
3.3 Survey Methodology
The intent of the sound level survey was to quantify existing ambient sound levels across the
Project area. Four locations were chosen for ambient sound level measurements. Location 1 was
located near the proposed intake and powerhouse locations, capturing the sound of the falls and
other natural sounds. This was used to represent the existing ambient sound level for areas within
one-half mile of the intake and powerhouse. Location 2 was chosen to represent ambient sound
levels in areas remote from the falls and typical of natural ambient sound levels in the general
noise study area distant from the falls. Locations 3 and 4 were located close to the Royal
Coachman Lodge and were used to quantify sounds from typical lodge activities including
HVAC, power generation equipment, and air traffic. Table 3-3 shows the site-specific details for
each measurement location. Figure 3-1 shows an aerial photograph of the Project area with the
measurement locations marked.
The ambient sound study was performed from June 13th to 14th, 2023 by Cory Schmidt of SLR.
Measurements were approximately 24-hours in duration at the four locations. Sound levels were
measured using the slow meter response and A-weighting. Data were collected in 1/3-octave
bands and recorded in 10-second and 15-minute sampling periods.
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Table 3-3. Ambient Survey Sound Level Measurement Details.
Measurement Location GPS Coordinates
Approx. Distance from
Center of Proposed Project
Powerhouse, (Feet)
Direction
Location 1 59.91066°N
-158.12027°W 850 Northwest
Location 2 59.90760°N
-158.17971°W 11,300 West
Location 3 59.92540°N
-158.18454°W 13,600 WNW
Location 4 59.92547°N
-158.18187°W 13,300 WNW
Location 1
Location 2
Location 3
Location 4
Figure 3-2. Ambient Survey Location Photos
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 8 December 2023
3.4 Measurement Equipment
Sound level equipment used during the ambient sound study included the following instruments:
Larson Davis 824 SLMs; Type 1; s/n A0424, A0976, A0197, A0355
Larson Davis CAL200 Calibrator; s/n 15533
A windscreen was used on the measurement microphones. The sound level meters were field-
calibrated before and after measurement intervals. All instruments have current laboratory
certification that can be provided upon request. Measurements were conducted five feet above
the ground.
3.5 Weather Conditions
Weather conditions were appropriate for a sound level study. A summary of the weather
conditions is shown in Table 3-4.
Table 3-4. Summary of Weather Conditions
Date June 13th – 14th, 2023
Temperature Range 35°F – 54°F
Relative Humidity 57% - 99%
Wind Speed (Average) 5.5 mph
Wind From Variable
Sky Condition Cloudy
Ground Condition Damp
Complete weather data from the measurement survey were obtained from a nearby weather station
using www.wunderground.com.
3.6 Modeling Methodology
A three-dimensional computer noise model was developed to analyze the noise contributions
from the various phases of the Project. The model was developed using CadnaA, version 2023
build 197.5343, a commercial noise modeling package developed by DataKustik GmbH. The
software considers spreading losses, ground and atmospheric effects, shielding from barriers and
buildings, reflections from surfaces and other sound propagation properties. The software is
based on published engineering standards. The ISO 9613-2 standard was used for air absorption
and other noise propagation calculations.
To be conservative, the noise reduction effects of foliage were not included in the noise model.
The predicted sound levels show the predicted sound levels without any reduction due to the
heavy foliage in the Project area. With this assumption, the noise model will tend to overstate
the potential sound levels from the Project phases.
The terrain was modeled based on USGS topographical data at a resolution of 5 by 5 meters. A
temperature of 20 degrees Celsius and 70 percent relative humidity were used for the
Nuyakuk River Hydroelectric Project Noise Study
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atmospheric absorption calculations. The ground was modeled as mixed, with a G = 0.5
absorption coefficient. The number of reflections was set to 2 for the model.
Standard meteorological conditions as per ISO 9613-2 were used to conservatively calculate
sound level contributions at the receptors. These assume a stable atmosphere consistent with
early morning and evening twilight conditions along with a light, downwind condition from the
Project to the receptor.
3.7 Model Data and Assumptions
3.7.1 General Construction
Noise from general construction activities will cause a temporary noise impact for areas close to
the site of the intake and powerhouse. In order to quantify the full extent of this impact, a noise
model of the proposed construction equipment was developed. Construction is planned for
daytime hours only.
Sound power levels for the Project equipment and construction activities were based on similar
equipment from previous SLR projects and the Roadway Construction Noise Model (FHWA
2020). A list of potential construction equipment was provided by the Project team and was used
to calculate the utilization factors and sound power levels for construction equipment.
Table 3-5 shows the construction equipment included in the noise assessment for the intake and
powerhouse area of the Project. The usage factor and quantity of each piece of equipment was
used in conjunction with the rated sound level at 50 feet to calculate the usage and quantity
adjusted sound level for each equipment item. The total calculated construction sound power
level of 120 dBA was calculated from the individual sound pressure levels. The spectrum and
overall sound power level for the construction activities are shown in Table 3-6.
Table 3-5. Construction Equipment Included in Assessment - Intake and Powerhouse
Client Equipment List RCNM
Equivalent QuantityUsage
Factor
Sound
Pressure
Leq at
50', dBA
Usage
Adj.
Sound
Pressure
Leq at 50',
dBA
Usage and
Quantity
Adjusted
Sound
Pressure
Level @ 50'
CAT D6 Dozer Dozer 1 0.4 81.7 77.7 77.7
CAT 301 Sized Mini
Excavator Excavator 1 0.4 80.7 76.7 76.7
CAT 336 Sized Excavator Excavator 1 0.4 80.7 76.7 76.7
CAT 349 Sized Excavator Excavator 1 0.4 80.7 76.7 76.7
Long Reach Excavator Excavator 1 0.4 80.7 76.7 76.7
All Terrain Forklift (10K) Tractor 1 0.4 80.0 76.0 76.0
CAT 966 Sized Loader Front End Loader 1 0.4 79.1 75.1 75.1
CAT 272 Sized Skid Loader Front End Loader 1 0.4 79.1 75.1 75.1
Blast Hole Drill Rig Drill Rig Truck 1 0.2 79.1 72.1 72.1
5kW Light Plant Light Plant 1 1.0 57.0 57.0 57.0
F350 Sized Pickup Pickup Truck 1 0.4 75.0 71.0 71.0
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 10 December 2023
Client Equipment List RCNM
Equivalent
QuantityUsage
Factor
Sound
Pressure
Leq at
50', dBA
Usage
Adj.
Sound
Pressure
Leq at 50',
dBA
Usage and
Quantity
Adjusted
Sound
Pressure
Level @ 50'
F550 Sized Pickup Pickup Truck 1 0.4 75.0 71.0 71.0
Vibrating Roller – 48” Sized
Drum Roller 1 0.2 80.0 73.0 73.0
Water Truck – 2000 Gals
Vacuum
Excavator (Vac-
truck)
1 0.4 85.3 81.3 81.3
Diesel Pile Hammer
Mounted Impact
Hammer (hoe
ram)
1 0.2 90.3 83.3 83.3
Diesel Generator Generator 1 0.5 80.6 77.6 77.6
Hydraulic Power Unit
All Other
Equipment > 5
HP
1 0.5 82.0 79.0 79.0
Crawler Crane – 150Ton Crane 1 0.2 80.6 72.6 72.6
Air Compressor Compressor (air) 1 0.4 77.7 73.7 73.7
3.7.2 Blasting
Calculations were conducted for the potential blasting noise based on standard blasting
methodologies from the International Society of Explosive Engineers (ISEE). The criteria levels
were used to calculate the maximum allowable charge weight per delay that would result in peak
sound levels at the receptor locations that would just meet the criteria levels. In other words,
calculations were performed to determine how many pounds of explosive would result in levels
of 115 to 134 dB peak at receptor locations.
3.7.3 Operations
Four roof-mounted exhaust fans were assumed for the powerhouse during normal operating
conditions. Based on the current design, there are no other significant operational noise sources
expected for the project. The sound power level used for each of the powerhouse fans is shown
in Table 3-6. As long as the exhaust fans specified for the Project have sound power levels
similar to or lower than these sound power levels, the impact assessment will be conservative.
3.7.4 Air Traffic
A report from the U.S. Department of Transportation (USDOT 2012) was used for floatplane
sound power level calculations. The report references two types of fixed wing aircraft: Cessna
182S Skylane and De Havilland Canada DHC-2 Beaver. There is no definite proposed schedule
for aircraft traffic during normal operations, but the expectation is that there will be one aircraft a
week or less. The aircraft sound power level used in the noise model is shown in Table 3-6.
Table 3-6. Sound Power Levels (Lw) for Proposed Project Equipment
Source Linear Lw at Octave Center Frequency, Hz Total
31.5 63 125 250 500 1k 2k 4k 8k dBA
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 11 December 2023
Construction Noise, Lw 113 118 118 123 118 113 108 103 98 120
Powerhouse Roof Exhaust Fan
per Fan, Lw
106 106 103 99 98 95 91 88 87 100
Aircraft Noise, Lw 123 136 149 142 143 140 137 128 114 145
4.0 MEASUREMENT RESULTS
4.1 Sound Level Measurements
Measurement durations and field observations of the audible sound sources at each measurement
location are summarized in Table 4-1.
Table 4-1. Summary of Measurement Field Observations
Measurement
Location
Measurement
Duration
HH:MM
Source Observations During Measurements
Location 1 24:29 Audible sound sources at this location included birds, wind, and
water noise from the falls.
Location 2 24:18 Audible sound sources at this location included birds, wind, and
rain. Occasional distant aircraft noise was audible.
Location 3 24:06
Audible sound sources at this location included birds, wind,
water noise, and a generator at the Royal Coachman facility.
Occasional aircraft activity noise was very loud.
Location 4 24:14
Audible sound sources at this location included birds, wind,
water noise, and a generator at the Royal Coachman facility.
Occasional aircraft activity noise was very loud.
4.2 Results
The sound level measurement results are summarized in Table 4-2. All measurement results are
inclusive of all environmental sounds, such as birds, wind, aircraft activity, and water noise.
Table 4-2. Summary of Sound Level Measurement Results
Measurement
Location
Approx. Distance from
Center of Proposed
Powerhouse, Feet
Direction Daytime
Ld, dBA
Nighttime
Ln, dBA
Day-Night
Ldn, dBA
Location 1 850 Northwest 53.0 53.3 59.6
Location 2 11,300 West 49.2 43.3 51.3
Location 3 13,600 WNW 68.2 41.5 66.2
Location 4 13,300 WNW 67.4 43.4 65.5
Level vs. Time graphs from each measurement location are included in Appendix O-1. Each
graph displays measurements at a single location. The top section of each graph shows the 10-
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 12 December 2023
second Leq represented by a solid blue line, the 15-minute Leq represented by a stepped red line,
and the 15-minute L90, represented as a stepped green line.
The bottom section of the graphs shows the frequency-based data. Sound frequency is plotted on
the vertical axis and time on the horizontal axis. The color indicates the A-weighted sound
pressure level at each frequency. The frequency data is useful for determining the presence of
any tonal frequencies and helps to characterize the presence of specific noise emissions. For
example, the presence of bird noise is clearly visible at Location 2 as scattered high-frequency
sounds starting at about 3:00 AM on June 14th.
4.3 Ambient Level Discussion
Sound levels at Location 1 were controlled by noise from the nearby falls. Other sounds in the
area included birds and insect noises but these had no effect on the measured sound levels as
these levels were controlled by sounds from the falls.
Sound levels at Location 2 were the lowest of the four measurement locations. Sound levels
included very quiet sound levels from the distant falls, leaf rustle due to wind, and significant
bird and insect activity. Nighttime sound levels at this location dropped to 15-minute average
levels of less than 25 dBA and 15-minute L90 levels of around 20 dBA. Sound levels this low are
typically found only in remote rural areas.
24-hour sound levels at Locations 3 and 4 were controlled by water flow from the Nuyakuk
River and noise from the falls on the Nuyakuk River close to Tikchik Lake. Power generation
equipment at the Royal Coachman lodge was clearly audible at both measurement locations, but
the overall A-weighted sound levels didn’t change significantly when this equipment was
shutdown during nighttime hours, starting at about 11:00 pm and then started again at 5:00 am.
This indicates that the broadband noise from the river and falls was the controlling source in the
area.
There were a few short-term loud events that were significant for the overall average sound
levels at Locations 3 and 4. These were events related to outboard motors for watercraft on the
Nuyakuk River and to aircraft operations associated with the Royal Coachman Lodge. Sound
levels without these activities were controlled by water flow noise and were typically 40 to 43
dBA during periods without the nearby generator in operation.
Table 4-3 shows the lowest 15-minute daytime and nighttime sound levels at each measurement
location. These levels are representative of the lowest expected sound levels under typical
circumstances. These levels were used to develop the ambient sound model of the area and were
used to derive the impact assessment for long-term continuous sounds such as operations noise
and general construction activities.
Table 4-3. Summary of Sound Level Measurement Results – Baseline Levels
Measurement
Location
Approx.
Distance
from Center
of Proposed
Direction
Lowest
Daytime
L(15-min),
dBA
Lowest
Nighttime
L(15 min),
dBA
Resulting
Day-
Night
Ldn, dBA
Filtering Applied
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 13 December 2023
Powerhouse,
Feet
Location 1 850 Northwest 52.2 52.7 59.0
Lowest 15-minute
Sample, Daytime
and Nighttime Leq
Location 2 11,300 West 30.0 22.5 31.1
Location 3 13,600 WNW 41.1 39.9 46.5
Location 4 13,300 WNW 42.7 42.7 49.1
5.0 NOISE IMPACT ASSESSMENT
5.1 Ambient Model
Noise impact is assessed by comparing the predicted sound levels from the Project phases with
the ambient sound levels. Typically, this analysis is performed at specific receptors. In this case,
because there is concern about noise impact across the entire noise study area, an ambient sound
level model was developed. The ambient model includes the two separate falls as well as an
overall baseline ambient level, due to birds, leaf rustle and other ambient sounds, of about 20
dBA. The results of each Project phase noise model were compared to the ambient sound levels
to determine the potential change in sound level at the given location due to the Project.
5.2 Construction Noise – Typical Equipment
Predicted sound levels due to daytime construction activity are shown in Table 5-1.
Table 5-1. Predicted Construction Sound Levels
Location
Predicted
Sound Level
due to
Construction
Activities
Meas.
Sound
Level
Baseline
Sound
Level
Predicted Sound
Levels during
Construction
Potential Short
Term Increase
during
Construction
Overall Baseline Overall Baseline
Location 1 - Edge of
Project Area 57.0 53.0 52.2 58.5 58.2 5.5 6.0
Location 2 - 11,151 ft.
West of Project 24.5 49.2 30.0 49.2 31.1 0.0 1.1
Location 3 - Royal
Coachman Lodge 22.9 67.4 41.1 67.4 41.2 0.0 0.1
All levels shown are A-weighted decibels, daytime (7:00 AM to 10:00 PM)
Figure 5-1 shows the predicted change in sound level over daytime baseline ambient sound
levels due to construction activities. The predicted change in sound level is shown as lines of
equal levels of increase.
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 15 December 2023
5.3 Construction Noise – Blasting
Blasting will likely be used during the construction of the flow tunnel from the intake area to the
powerhouse. This will be a relatively small area of construction blasting and the total explosive
necessary per blast is likely to be quite small. Blasting will be timed to take place during non-
peak periods for recreational uses, to avoid the fishing season at the Royal Coachman Lodge.
Depending on the frequency of blasting proposed for the Project, which is as yet undetermined, a
blasting criteria of 115 to 134 dB peak was used (see Section 4.1.3). Calculations of the
expected overpressure from blasting were calculated using the standard construction blasting
curve (ISEE 2011). With this prediction curve and assuming only moderately confined blasting,
as might occur during the first few blasts, the charge weight per delay that would result in a
sound level of 115 dB at the Royal Coachman Lodge was calculated as 100 pounds of explosive.
A charge weight per delay of 650 pounds would result in a sound pressure level of 133 dB at the
Royal Coachman Lodge.
5.4 Normal Operation
Once the Project is constructed, the noise associated with normal operations will consist of noise
from powerhouse ventilation fans. This is assumed to consist of four roof-mounted exhaust fans
with the sound power level specified in Table 3-6. There is no expected increase of noise at the
water intake or discharge, and no expected sound to be audible from the generators/turbines
located in the basement of the powerhouse.
Noise model results for normal operation are presented in Table 5-2. Operations sound levels
have been compared to the measured nighttime ambient levels, as operations will be 24-hour per
day and lower nighttime sound levels and will show the largest potential impact of operations
noise.
Table 5-2. Summary of Noise Model Results – Normal Operation
Location
Predicted
Sound
Level due
to
Operations
Meas.
Sound
Level
Baseline
Sound
Level
Predicted Sound
Levels during
Operations
Potential Increase
during Operations
Overall Baseline Overall Baseline
Location 1 - Edge of
Project Area 36.9 53.3 52.7 53.4 52.8 0.1 0.1
Location 2 - 11,151 ft.
West of Project 10.8 43.3 22.5 43.4 22.8 0.0 0.3
Location 3 - Royal
Coachman Lodge 9.6 41.5 39.9 41.5 39.9 0.0 0.0
All levels shown are A-weighted decibels, nighttime (10:00 PM to 7:00 AM)
Figure 5-2 shows the predicted increase in nighttime sound levels due to operations. The
predicted change in sound level is shown as lines of equal increase in level.
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 17 December 2023
5.5 Aircraft Operations
Aircraft traffic is a common occurrence Project area. Floatplanes are the most common mode of
transportation for guests of the Royal Coachman Lodge, and flights are common for supply
deliveries. There will be additional aircraft traffic in the area once the Project is operating for
staff changes and resupply. The Project team estimates that approximately one flight a week
may be typical for standard operations, but that the number of flights could decrease over the life
of the Project.
Long-term average sound levels will not be affected by the small number of flights predicted for
the Project. Flights will be made with typical aircraft for the area: Cessnas, DeHavilland
Beavers, and similar aircraft. The sound levels at the Royal Coachman from these aircraft
overflights will be lower than for current flight operations, because Project flight operations will
be significantly farther away.
Measured sound levels due to aircraft operations at Locations 3 and 4, close to the Royal
Coachman Lodge, ranged up to between 95 and 100 dBA (10-second Leq) and resulted in 15-
minute average sound levels of 65 to 80 dBA.
Predicted sound levels for similar aircraft operating at the proposed Project runway and river
landing areas close to the Project are 15-minute average sound levels of 36 dBA at the Royal
Coachman Lodge. These will be significantly quieter than the 65 to 80 dBA 15-minute averages
for aircraft operations in the ambient survey results for Locations 3 and 4. While these aircraft
operations will likely be audible at the Royal Coachman Lodge, the levels are low enough to be
compatible with existing recreational use.
6.0 DISCUSSION AND FINDINGS
Generally, the predicted sound level impacts of the proposed Project activities are not significant.
The overall noise impact is expected to be limited to the area surrounding the intake and
powerhouse area.
During the short-term construction period, the noise model indicates that predicted sound levels
at the Royal Coachman Lodge from construction activities are 22.9 dBA, which is considerably
lower than the existing overall and baseline ambient daytime sound levels. This level is
significantly lower than the FERC construction noise limit of 48.6 dBA. The predicted change
in sound level of 0.1 dBA would be completely imperceptible.
Construction sound levels will be occasionally perceptible at about 6,500 feet from the Project
during general construction activities, causing an increase of about three decibels to the quietest
daytime 15-minute period. Construction activities will be clearly audible during the quietest
daytime 15-minute period at about 4,000 feet from the site. Significant sound impacts,
represented as a temporary daytime increase of 10 decibels, will occur at a distance of about
2,000 feet from the site.
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 18 December 2023
Given that the current investigation is intended to assess overall Project feasibility, a blasting
plan has not been developed for the construction activities at the site. Based on standard blasting
criteria and the construction blasting prediction curve, a charge weight per delay of 100 pounds
will result in a sound pressure level of 115 dB Peak at the Royal Coachman Lodge. This sound
level is generally considered acceptable even for multiple repeated blast exposures for people,
and it would be considered compatible with daytime recreational land use.
Due to the limited equipment involved in the operation of the Project, noise impacts are
insignificant. The operating facility equipment may be barely perceptible (with an increase of
three decibels) during the quietest 15-minute daytime period at distances of about 2,500 feet
from the powerhouse. Sound levels from the Project operations are expected to be less than 10
dBA at the Royal Coachman Lodge and should be completely inaudible at that distance.
Similarly, the potential increase in sound levels due to the limited aircraft traffic proposed for the
construction and operations of the Project are expected to be compatible with recreational land
uses and the existing acoustical environment.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no significant variations from the study plan for the noise study. The ambient sound
level survey locations were field-selected based on accessibility and safety concerns and are
slightly different than the proposed locations suggested in the study plan. However, the intent of
the survey was satisfied, and the existing sound levels were well defined.
8.0 STUDY STATUS AND SCHEDULE
The noise study scope is complete. This ISR has been issued for review and comment. No
additional noise study work is planned at this time.
9.0 STUDY-SPECIFIC CONSULTATION
As is standard in the Integrated Licensing Process, the Proposed and Revised Study Plans were
provided to all interested Project participants (via FERC filing and the Project website) on March
20, 2020 and August 1, 2022 respectively for review. Based both on that feedback and proactive
collaborative dialogue, this study was developed. This report, along with the entirety of the
Initial Study Report and all studies documented therein will be distributed to the stakeholder
group for review in parallel with its filing with FERC.
10.0 REFERENCES
BBN (Bolt Beranek and Newman, Inc.). 1973. “Fundamentals and Abatement of Highway
Traffic Noise” Report No. PB-222-703, Prepared for the Federal Highway
Administration, June 1973.
Nuyakuk River Hydroelectric Project Noise Study
FERC No. 14873 Initial Study Report – Attachment O
Nushagak Cooperative, Inc. 19 December 2023
CFR (Code of Federal Regulations). 2017. 30 CFR 816.67 “Use of explosives: Control of
adverse effects”. Code of the Federal Register, Chapter VII, Subchapter K, Part 816.
FHWA (Federal Highway Administration). 2020. Roadway Construction Noise Model, Version
2.0. Obtained online at
https://www.fhwa.dot.gov/environment/noise/construction_noise/rcnm2/ Accessed
August 2023.
FERC (Federal Energy Regulatory Commission). 2017. Office of Energy Projects “Guidance
Manual for Resource Report Preparation” Volume I.
ISEE (International Society of Explosives Engineers). 2011. “ISEE Blasters Handbook”, 18th
Edition. ISEE, Cleveland, Ohio.
USDOL (U.S. Department of Labor). 2016. “Occupational Health and Safety Administration
Technical Manual” Obtained online at
https://www.osha.gov/dts/osta/otm/new_noise/index.html. Accessed August 2023.
USDOT (U.S. Department of Transportation). 2012. “Floatplane Source Noise Measurements –
Summary of Measurements, Data and Analyses for the Cessna 182S and De Havilland
DHC-2 Beaver” DOT-VNTSC-FAA-11-11.
APPENDIX :
INITIAL STUDY REPORT
ATTACHMENT P: RECREATION INVENTORY BY SEASON
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 2
4.0 METHODOLOGY ............................................................................................................. 4
4.1 Methodology for Work conducted in 2023:............................................................ 4
4.1.1 On Site Field Observation and Intercept Surveys at Nuyakuk River Falls
(July 14-19, 2023). ...................................................................................... 4
4.1.2 Initial outreach to Commercial Use Permit Holders and Recreational
Business Operators...................................................................................... 5
4.1.3 Initial outreach to Village Representative for a public meeting and
engagement with residents to conduct use surveys..................................... 5
4.2 Methodology for Work to be conducted in 2024: ................................................... 5
4.2.1 Resident Surveys (Community Visits): ...................................................... 5
4.2.2 Resident Survey Results (Community Visits):........................................... 6
4.2.3 Recreational Business Operator Data Collection and Analysis: ................. 6
5.0 RESULTS ........................................................................................................................... 6
5.1 Field Observations, July 2023: ............................................................................... 6
5.1.1 The Falls and their Recreational Opportunities .......................................... 6
5.1.2 Observed Recreation & Visitation Pattern Overview ................................. 8
5.2 Intercept Survey Results ....................................................................................... 10
5.2.1 Primary Activity: ...................................................................................... 11
5.2.2 Who is Visiting:........................................................................................ 11
5.2.3 Desired Experiences and Lasting Benefits: .............................................. 11
6.0 DISCUSSION AND FINDINGS...................................................................................... 12
6.1 Summer visitation pattern ..................................................................................... 12
6.2 Additional study in 2024:...................................................................................... 12
6.3 Potential impacts to recreation for consideration: ................................................ 12
6.3.1 Changes that could affect fishing access along the south shoreline ......... 12
6.3.2 Increased evidence of human development: Visual and experiential
impacts...................................................................................................... 13
6.3.3 Potential increase in access opportunities ................................................. 13
7.0 STUDY VARIANCES AND MODIFICATIONS........................................................... 15
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. iii December 2023
7.1 Resident Surveys and Site Visits.......................................................................... 15
7.2 Field Observations and Intercept Surveys ............................................................ 16
8.0 STUDY STATUS AND SCHEDULE.............................................................................. 16
9.0 STUDY-SPECIFIC CONSULTATION ........................................................................... 16
LIST OF FIGURES
Figure 3-1. Nuyakuk Falls viewed from the air, looking southeast, downstream. ..........................2
Figure 3-2: Recreation study area ....................................................................................................3
Figure 4-1: Features and landmarks of the Nuyakuk Falls area. .....................................................4
Figure 5-1: Lower Falls detail showing approximate wadable fishing area (green polygons)
along each shoreline based on river levels at the time of field observation. ...........8
Figure 5-2: Relative locations of nearby commercial guiding operations.......................................9
APPENDICES
Appendix P-1 Commercial Operator Data Collection Form
Appendix P-2 Field Study Notes
Appendix P-3 Recreation Intercept Survey
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. iv December 2023
ACRONYMS AND ABBREVIATIONS
ADNR Alaska Department of Natural Resources
Cooperative Nushagak Electric & Telephone Cooperative
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
Project Nuyakuk River Hydroelectric Project (P-14873)
USR Updated Study Report
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
A comprehensive recreational survey will be employed in Dillingham and proposed Project-
serving villages four times (seasonally) using an online portal. The portal will be developed and
advertised in advance of the first set of surveys and contacts on the existing Project licensing
contact list as well as the public will be invited to submit survey responses. Supplemental
methods to the online portal were anticipated to reach a robust enough data set to make
conclusive determinations related to potential recreational impacts associated with Project
development. Supplemental survey distribution methods will include:
Seasonal village site visits to conduct surveys
Mailing of surveys to public individuals with instructions on mailing back
Phone calls to conduct surveys
Distribution of a survey package at local meeting places with instructions on mailing
back
Surveys conducted in the villages will be supplemented by on-site opportunistic recreation
observations by natural resource study personnel, regardless of disciple. All individuals
conducting studies near the proposed Project location at Nuyakuk Falls (Falls) will be briefed
prior to departing on recreational data to collect and will record any activities observed while on-
site.
Alterations to this study plan were made and carried out in 2023. See Section 7 Study Variances
and Modifications for details.
2.0 STUDY GOALS AND OBJECTIVES
The goal of the study is to inventory and quantify the type and volume of recreational use
occurring during each season in the vicinity surrounding the proposed Project facilities on the
Nuyakuk River.
The proposed Project is located within Wood-Tikchik State Park, managed by the Alaska
Department of Natural Resources (ADNR). Therefore, understanding any potential Project
impacts (positive or negative) to recreation within Wood-Tikchik State Park near proposed
Project infrastructure is essential for ensuring ADNR is able to manage and protect resources
within the park. While existing recreational use in Wood-Tikchik State Park includes skiing, off-
road vehicle use, boating, sightseeing, hiking, hunting, and fishing among other uses, the specific
activities and volume of recreational use in the immediate Project vicinity that may be impacted
by Project development is unknown but anticipated to be limited, especially due to its remote
location.
The objectives of the Recreation Study include documenting and developing an understanding of
personal recreational activities as well as commercial recreational activities within the Project
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 2 December 2023
Area during each season. Construction and operation of the proposed Project may impact
recreational use of the area surround the Project facilities. Site-specific recreational use
information may be used to develop mitigation measures for Project construction and operation,
if necessary.
3.0 STUDY AREA
The recreation inventory is focused on use in the area immediately around the proposed Project
river infrastructure (intake, tunnel, powerhouse, etc.). The geographic scope of the recreation
study area spans from approximately ½ mile upstream of the proposed Project intake to 1 mile
downstream of the proposed Project tailrace.
Data collection is extended to residents of communities and villages on the proposed Project
transmission corridor; Dillingham, Koliganek, New Stuyahok, Ekwok, Levelock, and Aleknagik.
Figure 3-1. Nuyakuk Falls viewed from the air, looking southeast, downstream.
Nuyakuk River Hydroelectric Project Recreation Inventory by SeasonFERC No. 14873 Initial Study Report – Attachment P Nushagak Cooperative, Inc. 3 December 2023Figure 3-2: Recreation study area
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 4 December 2023
4.0 METHODOLOGY
4.1 Methodology for Work conducted in 2023:
4.1.1 On Site Field Observation and Intercept Surveys at Nuyakuk River Falls (July
14-19, 2023).
Two staff conducted observations of land, water, and air reasonably accessible or observable
along the Nuyakuk River within the study area. Activity was recorded generally from 8:00 AM
to 5:00 PM with additional notes taken, as observed while on site for six days (July 14-19, 2023).
Observations occurred primarily from the Portage Trail (Figure 4-1) or by boat on the Nuyakuk
River, above and below the Falls. Additional air observation occurred from the Cooperative field
camp.
Figure 4-1: Features and landmarks of the Nuyakuk Falls area.
Intercept surveys were conducted with recreators when practical, with participant and guide
consent. Staff introduced the project and purpose of their surveys and either read the questions to
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 5 December 2023
participants or had participants fill out the paper surveys themselves. Responses were compiled
and analyzed.
The Royal Coachman Lodge was alerted of the upcoming field work via email on June 7th. The
Royal Coachman Lodge and Tikchik Narrows Lodge were contacted via email on July 15th after
Recreation Study staff arrival and set up at the field camp, alerting them to staff’s presence and
desire to conduct intercept surveys with their clients while recreating near the Falls. See Figure
5-2 for lodge locations.
4.1.2 Initial outreach to Commercial Use Permit Holders and Recreational Business
Operators.
Staff developed a Data Collection Form for commercial operators to determine activity types,
quantify frequency and volume of trips and number of customers, as well as understand the
importance or significance of the Nuyakuk Falls area for their operations. The list of 2022 State
Park CUP holders was acquired and reviewed, and staff will request ‘23-24 list during the 2024
study year. Data Collection Forms will be sent out via email and phone calls will be made to
follow up with nonrespondents. Paper forms will be available by request.
4.1.3 Initial outreach to Village Representative for a public meeting and engagement
with residents to conduct use surveys.
Working with and through the Cooperative, initial coordination with village leaders to identify
an appropriate date, time, and location for meetings to present a Project update and for Rec Study
staff to conduct surveys in person began in late August and early September. Some village
representatives expressed support for distributing paper surveys in their community following
the meetings. Unfortunately, no compatible result was identified to visit all the villages within
consecutive days during September or October. See section 4.2 Methodology for Work to be
conducted in 2024 for continuing coordination efforts.
4.2 Methodology for Work to be conducted in 2024:
4.2.1 Resident Surveys (Community Visits):
Paper and online versions of the survey will be developed, distributed, and advertised to
residents within the identified communities near the time of the in-person meetings with the
Cooperative at gathering places in each community. The meeting will introduce the recreation
study and its purpose, allow staff to engage in meaningful conversations with residents,
administer the surveys in person, and assist those with limited written ability in answering survey
questions.
Paper surveys will be distributed after the meeting and placed in a central location with prepaid
return envelopes for those unable to attend the meeting. Flyers, informational notices, and other
advertisements will be distributed using methods recommended by community leaders to
maximize effectiveness.
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 6 December 2023
4.2.2 Resident Survey Results (Community Visits):
Recreation Study staff will return to the communities to present the results of the recreation
resident survey thus far, along with other study area results as practical, and ask for additional
information to ensure an accurate understanding of recreational use of the Nuyakuk Falls areas
from their perspective has been documented.
4.2.3 Recreational Business Operator Data Collection and Analysis:
Email, phone calls, and in-person conversations, as time permits, during community visits will
be used to engage with Wood Tikchik State Park Commercial Use Permit holders and other
recreational businesses operating within the identified communities to collect use data around
Nuyakuk Falls.
The fillable data collection form developed in the 2023 study year will be sent to all with clear
instructions on how to complete the form and submit back to Rec Study Staff (see Appendix P-1
Commercial Operator Data Collection Form). Contact will be made in the winter/spring of 2024
to collect 2018-2023 data as it is available, again in early May 2024 to remind operators that we
will be requesting this data for their 2024 season in hopes that they document it, and a final time
in September/October 2024 to collect 2024 data for analysis. Inquiry will also be made to Wood
Tikchik State Park staff for any reporting submitted to them by commercial use permit holders
regarding recreational visitation and use patterns in the Project vicinity.
5.0 RESULTS
5.1 Field Observations, July 2023:
Observations are summarized in the following sections. See Recreation Study Appendix P-2:
Field Study Notes for complete observations.
5.1.1 The Falls and their Recreational Opportunities
The Nuyakuk Falls are located on the Nuyakuk River five miles downstream from the outlet of
Tikchik Lake. The Falls are within Wood-Tikchik State Park managed by Alaska Department of
Natural Resources Division of Parks and Outdoor Recreation. The primary observed recreation
activity opportunities in the immediate area of the Falls include but are not limited to sport
fishing/angling, wildlife viewing, scenic viewing, paddling, motorized boating, and photography,
all in a remote setting with wilderness characteristics. See Figure 3-2: Recreation study area and
Figure 4-1: Features and landmarks of the Nuyakuk Falls area.
The Falls exist along a bend in the river less than 1/2 mile long with an elevation loss of
approximately 26 feet. This section of river presents several drops and large, continuous rapids.
Steep and cliff banks surround the whitewater. The size of the rapids, their continuous nature and
length, and few locations set safety qualify this section as Class IV and Class V whitewater at
observed water levels. Paddling trips down the Nuyakuk benefit from a well-defined portage trail
to allow safe navigation around the whitewater and Falls. The rapids are easily seen and heard
from upstream, providing paddlers ample time to move to shore and portage. The portage trail
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 7 December 2023
features a steep and sustained incline at both ends. To transport a heavy, motorized boat up and
over the trail would require considerable effort, manpower and tools, and thus appears unlikely
for a casual recreational visitor. The nearest year-round population reachable by boat is the
village of Koliganek, approximately 50 miles downstream from the Falls, followed by New
Stuyahok (80 miles) and Ekwok (90 miles) villages. Dillingham, the regional population center,
is located at the mouth of the Nushagak River, to which the Nuyakuk River is a tributary,
approximately 110 miles downstream of the Nuyakuk Falls. Trips by motorized boat from any of
these communities require an investment in time and gasoline, as well as familiarity with the
Nuyakuk River and navigational skill as the swift and rock strew nature of the river can make
travel difficult or risky.
The Falls form a natural bottleneck below which salmon congregate on their journey upriver to
spawn. Thousands of fish, mostly sockeye salmon, wait in the eddies below the rapids before
their attempt to swim up the Falls and continue upstream, or resting between failed attempts. The
presence of salmon also attracts other wildlife species. Observed during the field study were
many species of birds, other sport fish, and grizzly bears (a sow with cubs were seen on video
footage captured on trail cameras on the Portage Trail; no bears were observed in person from
land or water). The waterfalls seen from downstream are scenic and photogenic. The
combination of salmon and other sportfish, whitewater falls, and other wildlife make the lower
Falls a good location for recreational angling, wildlife viewing, and photography.
The area below the Falls offers two good fly-fishing spots to accommodate groups of anglers.
The location on the right side of the river (when facing downstream), at the eastern terminus of
the portage trail, is referred to as the South Eddy. The location on river left is referred to as
Grayling Beach. At most observed river levels, both shores offer shallower depths and slower
currents, making them generally wadable. The South Eddy has thick vegetation up to the river’s
edge such that fly fishing was only possible from within the river and required low enough river
levels to wade (this eddy may not be wadable at peak flows). Grayling Beach appeared to be the
preferred angling spot as it offered a small space of gravel shoreline free of vegetation, allowing
more space for casting at shallower depths, bigger groups, space to sit and break for meals, and
even room for a small campfire.
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 8 December 2023
Figure 5-1: Lower Falls detail showing approximate wadable fishing area (green polygons) along each
shoreline based on river levels at the time of field observation.
5.1.2 Observed Recreation & Visitation Pattern Overview
Observed recreational activity was limited to fly fishing immediately downstream of the Falls
and along the shorelines on each side of the river at Grayling Beach and the South Eddy. Visits
were exclusively made by two nearby lodges bringing clients on guided fishing trips, Tikchik
Narrows Lodge and Royal Coachmen Lodge. The only observed traffic upriver or downriver of
the Falls was motorboat or airplane taxiing to facilitate fly fishing experiences for guests of these
private lodges. Observations during the recreation field study period were consistent with the
anecdotal accounts throughout the summer from other researchers and the field camp host/bear
guard.
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 9 December 2023
5.1.2.1 Visitation volume and frequency:
A total of 38 visits (not counting pilots taxiing visitors to the area) were observed in the vicinity
of the Falls during the onsite study period. All visits were part of a guided fly-fishing experience.
Of the 38 visits, 27 were believed to be clients and unique visitors. Guided fly-fishing groups
visited the lower Falls site five out of the six days of observations: Tikchik Narrows Lodge
clients visited five different days and Royal Coachman Lodge clients visited two different days.
Total visitors to the area at any time ranged from three to ten people, including guides. Visitors
appeared to mostly be male and middle-to-advanced age.
5.1.2.2 Typical Access and Visitation Schedule:
Tikchik Narrows Lodge flew clients in a DeHavilland Beaver small airplane to the Nuyakuk
Falls. Tikchik’s Lodge is located on Tikchik Lake above the Nuyakuk Falls and the Tikchik
outlet rapids. Travel downstream by boat is not ideal. Tikchik flew clients to the area on all but
one day. The plane would land approximately one mile downstream. Here, clients were loaded
into boats and taken upstream to fish at Grayling Beach while the plane flew back to the lodge.
Tikchik’s planes typically landed between 8:00am and 11:00am to drop off clients. One or two
guides assisted between two and six clients each day. Clients fished with their guides for
between two and five hours, including sometimes a break for a meal and campfire. In the
Figure 5-2: Relative locations of nearby commercial guiding operations.
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 10 December 2023
afternoon the guides would finish cleaning the site and run the clients back to the landing area
where they would depart by plane, usually by 2:00pm or as late as 4:30pm.
Royal Coachman Lodge brought clients two of the six observation days. Other researchers noted
that they visit more frequently when the weather is not ideal for flying. The recreation field
observation period featured fair weather and mostly clear skies during an otherwise wet summer,
validating this assumption. Royal Coachman Lodge is located on the Nuyakuk River,
approximately four miles upstream from the Nuyakuk Falls, and immediately downstream of the
Tikchik Lake outlet rapids at the headwaters of the river. Royal Coachman brought their clients
downstream from the lodge by motorboat to the potage trail above the Falls. Guides and clients
hike eastward up and over the Portage trail to its terminus just below the Falls. Guides and
clients fished the South Eddy where Royal Coachman had another boat stationed. Royal
Coachman’s group sizes were smaller, with two clients each day observed and one or two
guides. Based on other accounts, group sizes could be as large as five or six, but these groups
were not observed by the recreation team during the field study. Royal Coachman groups arrived
around 8:00am-9:00am and fished for about two-three hours, leaving by noon.
5.1.2.3 Other observations:
Airplane traffic noise occurred daily, mostly by the two fishing lodges. Occasional plane traffic
was heard or seen in the area from other parties, including one small passenger jet that was seen
flying adjacent to the Falls. The study team only observed one instance of potential flight-seeing
by anyone other than the two lodges, when an unrecognized plane circled over the Falls.
No other recreational activity was observed during the field study period. There were no other
trails identifiable from our observation methods, and no clear camping areas.
There was one report of observed recreational activity provided by personnel of another study
discipline. While out on the river in early August, four people were observed camping near the
Lower Falls off the Portage Trail with their raft in the south eddy tied to shore. They had floated
the Upper River and portaged to the Lower Falls on the Portage Trail. Only one night of camping
was observed before they continued floating the Nuyakuk downriver.
5.2 Intercept Survey Results
Of the 38 total visits, and 27 unique client-visitors, the recreation study team recorded eight
intercept surveys (see Appendix P-3: Recreation Intercept Survey). All clients who were offered
surveys agreed to take them and completed them. Intercept survey samples were predictably low
due to a few factors, primarily the area’s extreme remote location and access limitations which
result in generally low overall visitation numbers. Secondly, reaching participants proved
challenging. Intercepting Tikchik Lodge visitors at Grayling Beach (the most-frequented fishing
spot) required landing a boat across the river in very limited space; a significant intrusion that
would undoubtedly disturb what was understood to be a rare and costly fishing experience.
Wanting to respect their experience, we did not approach fishermen on Grayling Beach. Our
other option, to intercept clients at their airplane pick-up and drop-off location, required precise
and fortunate timing: researchers needed to intercept the boat, talk with client participants and
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 11 December 2023
distribute surveys, retrieve completed surveys and be out of the way of the plane’s landing area
when they approached for landing. That timing rarely occurred, as the guide’s boat often landed
right before the plane came in. We anticipated more visits from Royal Coachmen Lodge guests,
who would come by boat from upriver, traverse the Portage Trail, and thus be easier to intercept.
Unfortunately, their visits were relatively infrequent during the recreation study. This was
presumed to be due to the fair weather (a rarity in an otherwise wet summer) that may have
allowed them to travel farther by plane to other productive rivers and rely less on visits to the
nearby Falls.
5.2.1 Primary Activity:
All respondents (100%) indicated that their visit was for recreational purposes and that “fishing”
or “angling” was their primary recreation activity. All were observed fly-fishing specifically. Six
respondents indicated they were targeting fish species during their trip, all of whom wrote a list
of multiple fish species. Six (75%) respondents also considered motorized boating and flight-
seeing as recreational activities in which they participated during their trip. Some respondents
also indicated they participated in watching wildlife (n=5; 62.5%), photography (n=2; 25%), and
family or social gatherings (n=2; 25%).
5.2.2 Who is Visiting:
All respondents identified as male, white, not Hispanic, and were over 55 years of age (75%
were 65 or older). No respondents were Alaska residents. All respondents were visiting the Falls
as part of a guided fishing experience with one of two private fishing lodges in the area. Of their
total trip durations (ranging 9-14 days long), all respondents expected to visit the Falls only once
during their current trip. Of eight, only one respondent indicated having visited the Falls before
(six times before), while all others were visiting for their first time. Most (62.5%) respondents
considered the Nuyakuk Falls important or very important among other trip considerations when
planning their route or trip.
5.2.3 Desired Experiences and Lasting Benefits:
To understand motivations for visits to this area, respondents were asked to rate the importance
they placed on achieving thirteen different experiences commonly associated with different
recreational outings. Ratings were on a 5-point Likert scale of level of importance, with 1
indicating “not at all important,” 3 indicating “somewhat important” and 5 indicating “extremely
important.” Mean respondent scores rank the following experiences as important or very
important: Experiencing new and different things (4.57); enjoying the sights and smells of nature
(4.25); being with friends (4.125); getting away from the usual demands of life (4.125); and
being away from crowds of people (4.125). Testing one’s abilities (3.25) and experiencing
solitude (3.125) were “somewhat important” on average. Bringing family closer together was
very important to some (three) and not important to the rest.
Respondents were also asked about the lasting benefits they hoped to gain from their visit to this
area of the Nuyakuk River. Respondents indicated on a 5-point Likert scale how desirable each
of a list of ten potential lasting benefits were as outcomes of their trip. According to respondents,
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 12 December 2023
the most desirable lasting benefits sought from the visit were: resting one’s mind from stress,
tension, or anxiety (3.875); a closer relationship with the natural world (3.625); and strengthened
ties with family and friends (3.5). Improving or maintaining one’s health was “somewhat
important” (3) on average.
6.0 DISCUSSION AND FINDINGS
Field observations provided a critical understanding of the area with respect to its layout and
recreational opportunities, remoteness, and the daily pattern of visitation in the summer months.
Overall findings point toward: a pattern of regular, sometimes daily, visitation for guided fishing
trips in the summer during favorable weather and fishing conditions (e.g. presence of salmon);
the need for further study of local and winter use of the area; the need to consider potential
impacts to common fishing spots and visual resources and viewsheds; and the need to consider
how potential increased access will be managed.
6.1 Summer visitation pattern
Based on field observations and initial conversations with stakeholders, guided fly fishing is the
primary activity in the summer when salmon are present. Visits by guided fishing groups are
regular, almost daily. The six-day field observation period confirmed what had been described
by other researchers. The proportion of overall park visitation represented by fishing at the Falls
is unknown and should be investigated in consultation with park staff. Data from commercial
operators may allow extrapolation to estimate the overall volume of visits to this area during
summer.
6.2 Additional study in 2024:
Summer field observation data can be supplemented and possibly extrapolated upon with
information from commercial operators and State Parks staff. Local and winter visitation patterns
still need to be understood, however. For instance, all intercept survey respondents were from
out-of-state. Local visitation habits still need to be understood; the study team will reach out to
village communities on and near the Nuyakuk River to understand local use and the importance
of the Falls and its features (see Section 4.2). This study does not assert that volume of local
visitation (or lack thereof) is necessarily indicative of the level of local or cultural importance of
the Project area.
6.3 Potential impacts to recreation for consideration:
6.3.1 Changes that could affect fishing access along the south shoreline
Based on July 2023 field observations, the fishing experience at the Falls is made possible and
enjoyable in a large part due to a limited amount of wadable space and vegetation-free shoreline.
In the event of development, careful consideration should be taken when choosing the location of
features like a tailrace outlet that might affect currents, depths, or shoreline topography near the
South Eddy, and could thus impact sport fishing access. Field observations did not suggest that
current use had maximized the number of anglers that can fish the area in view of the Falls, but
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 13 December 2023
space is limited. Because fly casting requires a large and flexible footprint with freedom to adjust
position, and given the desire of visitors to escape crowds, encroaching on these spots could have
a negative impact on those participating in the observed guided fishing experience. Shoreline
development could also positively impact fishing access, for example by selectively removing
vegetation, or changing grades such that more wadable area is accessible for fly casting.
6.3.2 Increased evidence of human development: Visual and experiential impacts
Getting away from crowds, experiencing nature and becoming closer with the natural world were
important experiences and desirable benefits for survey respondents. It is understandable why the
Nuyakuk Falls—a unique, inspiring, and beautiful natural feature—are likely an important draw
for the two lodges. Care should be taken in any development not to limit access to the scenic,
inspirational, and educational values offered by these Falls and the fish that migrate up them to
complete their lifecycle.
Worth noting is that the Falls represent only a single stop during a 9-14 day trip where clients
look for multiple fish species and experiences, flying to many locations and water bodies in the
region.
A sense of remoteness and natural setting may be highly important to current visitors and should
be protected. It is worth noting that, despite its remoteness and wilderness location, there is
regular evidence of human presence while visiting the area. While there is little physical impact
on the land (mostly confined just to the Portage Trail and the current Nushagak Cooperative
(Cooperative) research camp), visitors can expect daily airplane noise from the nearby lodges
and a very high probability of seeing at least one other party fishing most days.
Visual impacts will be important to consider in the event of development. Field observations
helped identify the main corridors used by humans and the primary vantage points from which to
evaluate visual impacts. Those include approaching the Falls by river from upstream, flying over
the Falls, approaching the Falls from downstream by boat, use of the portage trail, and vantages
from the prime fishing spots in view of the Falls at the South Eddy and Grayling Beach.
6.3.3 Potential increase in access opportunities
Site development could bring a few features that, if accessible to the public, could increase
visitation and activity in the area. A landing strip, if made public, could increase the type and
number of small aircraft that can access the area. This could increase activity, pressure, and
impacts (see 6.3.2) on the Falls area and beyond and facilitate more varied recreation use of the
area, though the magnitude is unknown.
Vegetation clearing may make a more hospitable location to camp. Currently there are few
clearings along the Portage trail to make a nice camp, especially for large groups. The
Cooperative currently occupies perhaps the best camp location, though it is intended to be
restored with vegetation after research concludes.
Managing increased access must be approached carefully. The remote, wilderness character of
the State Park and associated experiences rely on reducing crowds. If this location becomes more
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 14 December 2023
publicly accessible or an area where human activity concentrates, park management will want to
consider how to encourage dispersal around the Falls site or away from it to reduce human
impacts and crowding.
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 15 December 2023
7.0 STUDY VARIANCES AND MODIFICATIONS
Ahead of the 2023 Study Year 1 field season, Recreation Study staff held coordination meetings
with staff from ADF&G on their proposed subsistence study efforts, the Cooperative, and
Cultural and Terrestrial Study staff on FERC approved implementation methods to identify
opportunities for collaborative data collection, prevent redundant efforts, and on how to engage
effectively with residents of potentially impacted communities and Villages. Those
conversations yielded strong suggestions to modify the FERC approved study plan methods for
conducting resident survey and the reliance on other resource study area staff to observe,
document and report recreational activities observed while in the field.
7.1 Resident Surveys and Site Visits
A modification from traveling to each village four times in the calendar year (once per season) to
conduct resident surveys on recreation to only going once or twice within a year was
recommended by Recreation Study staff and confirmed and supported by those in the initial
coordination meetings. This modification was encouraged due to assumption that residents
would be able to sufficient recall any recreational activities they participated in at and around
Nuyakuk Falls during any season, that returning to ask the same questions each season was
unlikely to be well received by Village residents, and that making seasonal trips to their Villages
may be perceived as invasive. Additionally, village elders or representatives the Cooperative
have solid contacts with will have specific requests and recommendations for the appropriate and
best ways to distribute surveys within their communities.
Study methods for conducting resident surveys were modified from one trip per season in Study
Year 1 to two trips over a two-year study period; the first to introduce the study and conduct the
surveys and the second to present draft results to residents, ask for verification of information
collected, and to collect additional data as needed. Additionally, per recommendations and the
limited access to reliable internet, an online portal to conduct the resident surveys is no longer
the primary method of survey distribution, but secondary to in-person paper survey
administration and paper surveys with prepaid mailed envelopes for sending completed surveys
back to Recreation Study Staff. The recreation survey will be introduced in person to village
elders, community leaders, and residents at a public meeting in their preferred gathering place
ahead of dispersing the survey.
Study Year 1 Village Resident Recreation Surveys were attempted to be scheduled in early
October, after the main subsistence and sport fishing, hunting, and gathering seasons had
concluded. However, communications and logistics proved difficult between Nushagak,
Recreation Study staff, and consecutive availability of elders and leaders in the six communities.
Relying on and maintaining established positive relationships between the Cooperative and
contacts in all the proposed survey villages is a high priority and direct coordination with those
individuals to select the appropriate times and locations for the site visits will occur in late
2023/early 2024 and culminate in these visits taking place in 2024. Results from these surveys
will be incorporated into the Updated Study Report (USR).
Nuyakuk River Hydroelectric Project Recreation Inventory by Season
FERC No. 14873 Initial Study Report – Attachment P
Nushagak Cooperative, Inc. 16 December 2023
7.2 Field Observations and Intercept Surveys
Field Observations and Intercept Surveys were added to the FERC approved Study Plan. No in-
person observations of the study area were included in the initial study plan, leaving a critical
gap in opportunity for data collection. Under the initial Study Plan, observations were to be had,
documented, and reported by other resource study staff whenever they were in the field. This
additional effort would have required significant additional staff time and energy from staff
conducting specialized work in areas both within and beyond the recreation study area. The other
resource study staff would have varying schedules and locational needs to conduct their work
and therefore consistent observation of the study area would not have been feasible.
Additionally, no intercept surveys with recreators would have occurred.
Two staff went out to the field camp and observed recreational activities for 6 consecutive days
in mid-July, during an anticipated peak in salmon run. They recorded observations for their
entire time on site and engaged with area recreators when practicable.
8.0 STUDY STATUS AND SCHEDULE
The Recreation Study is ongoing, with survey work and commercial operator data being
collected during the remaining months of Study Year 1 (2023) through Study Year 2 (2024).
Activities in the Year 1 Study (2023) period for the Recreation Study included:
-Field Observations in July for 6 consecutive days with intercept surveys
-Initial coordination with community and village representatives for site visits
-Outreach to commercial use permit holders in Wood-Tikchik State Park for operator data
Activities in Study Year 2 (2024) will include:
-Two rounds of site visits in communities and villages to conduct the resident recreational
use survey and present preliminary results, anticipated for Early Spring 2024 and late
September to October 2024
-Commercial use permit holder data collection for 2018-2023 and 2024 seasons
9.0 STUDY-SPECIFIC CONSULTATION
Recreation Study efforts did not require significant formal consultations in the 2023 study year.
Full study effort consultations will be documented and summarized in the USR to be filed in
December 2024.
APPENDIX -:
Nuyakuk River Hydroelectric Concept, Recreation Study
Commercial Operator Data | DRAFT
Nushagak Cooperative is studying the feasibility of a hydroelectric project (Project) on the Nuyakuk River
which includes consideration of potential impacts to outdoor recreation. A recreation study is being
conducted to inventory and quantify the type and volume of recreational use occurring during each
season in the vicinity surrounding the proposed Project facilities. The proposed Project is on the Nuyakuk
River at the Nuyakuk Falls, roughly 4 ½ miles downstream from the outlet at Tikchik Lake. The recreation
study area of interest is from approximately ½ mile upstream of the proposed Project intake to 1 mile
downstream of the proposed Project tailrace (outlined in blue in the image below).
For more information on the proposed Project, please see www.nuyakukhydro.com.
(Online version will feature an interactive map of the study area)
As a Wood-Tikchik State Park Commercial User Permit holder or someone who operates a recreation
related business, you can help us gain a comprehensive understanding of recreational activities
occurring in the Project area.
Please provide the following information to the best of your ability to help us quantify recreation in the
Nuyakuk River Falls area. You are encouraged to share any additional information and expand upon the
data you provide.
Have questions or want to provide your information via phone or virtual meeting?
Please contact Taryn Oleson-Yelle at toleson@rmconsult.com or 907-646-9645.
Nuyakuk River Hydroelectric Concept, Recreation Study
Commercial Operator Data | DRAFT
Company/Organization: ________________________________________________________________
Your Name: ___________________________ Role: ________________________________________
Email: ________________________________ Phone: ______________________________________
1. What types of services does your business provide in Wood-Tikchik State Park?
Please include services offered any time between 2018 and 2024.
2. Do you provide any of your services in or near the vicinity of the proposed Project at Nuyakuk
River Falls? Services offered by air, land, and water are all of interest to the study.
Yes – if so, please continue.
No – if so, please skip to the last question (#12)
3. What recreational activities do your services support or provide?
Select all that apply.
a. Hiking
b. Fishing
c. Rafting
d. ATV or snowmachine riding
e. Motorized Boating
f. Canoeing or Kayaking
g. Camping
h. Photography
i. Flying and Sightseeing
j. Backpacking
k. Hunting Big Game
l. Hunting Small Game
m. Foraging or Harvesting
(mushrooms, berries, etc.)
n. Wildlife Watching
o. Other
4. What months of the year do you provide recreational services at this location?
Nuyakuk River Hydroelectric Concept, Recreation Study
Commercial Operator Data | DRAFT
5. How do you access the Nuyakuk Falls area?
Select all that apply.
Plane, float or ski
Motorized boat from above falls
Motorized boat from below falls
Raft, kayak or canoe from above falls
Raft, kayak or canoe from below falls
On foot or skis
Dog team
Snowmachine or ATV
Other: ______________________________________
6. How frequently do you operate in the Nuyakuk Falls area during the months indicated above?
a. Daily or almost daily
b. A few times per week
c. Once a week
d. A few times per month
e. Monthly
f. A few times per year
g. Once a year
h. Once every few years
7. On average, how many clients do you have on a single day of operation in the Nuyakuk Falls
area? (e.g., how many people per guided trip, how many groups or trips per day, etc.)
8. For the 2023 operating season, how many total clients did you provide recreational services to
in the Nuyakuk Falls area?
Nuyakuk River Hydroelectric Concept, Recreation Study
Commercial Operator Data | DRAFT
9. How does the 2023 season compare to previous years?
If you are able to provide previous full-year data, 2018 to current would be appreciated. Please
email toleson@rmconsult.com. (Online version may allow attachments within the question)
a. Fewer clients to Nuyakuk Falls area than previous years
b. About the same number of clients to Nuyakuk Falls area
c. More clients to Nuyakuk Falls than previous years
10. Approximately how many of your customers are Alaska residents vs. out-of-state visitors?
a. ____ % AK Residents
b. ____ % Out-of-State
11. How many employees contribute to providing recreational services on-site in the Nuyakuk
Falls area?
12. Do you provide support services or information about the Nuyakuk Falls area to your clients?
If so, please summarize or provide the information you share with clients.
Thank you for time and sharing your organization’s recreation related information. Responses will
be summarized and included in the Recreation Study inventory and factored into the feasibility
assessment of the proposed hydroelectric project.
APPENDIX -:
Nuyakuk River Hydroelectric Project | Nushagak Cooperative
RECREATION STUDY FIELD OBSERVATIONS
SUMMARY OF ACTIVITIES
R&M staff members Taryn Oleson-Yelle and Bryant Wright arrived at the field camp the afternoon of Thursday July 13th and began observations
the following morning. Accompanied by the camp host/bear guard, Shawn, Taryn and Bryant observed the area primarily by boat on the
Nuyakuk River or from the shoreline. The Portage Trail was observed when they were traveling on it as well as through the trail camera footage
collected by the camp host. Observations generally started between 9:00 AM and 10:00 AM depending on when boat or airplane traffic was
heard or seen. When opportunities arose, Taryn and Bryant approached recreators and requested their participation in surveys. Knowing clients
of the two lodges in the area, the Royal Coachman and Tikchik Narrows Lodge, paid for a particular wilderness experience and would be
accompanied by guides, Taryn and Bryant contacted the two lodges via email prior to and during their time on site alerting them of their
presence and purpose.
The areas considered for study observations included the land, water, and air reasonably observable or accessible along the Nuyakuk River
generally half a mile upstream of the falls and one mile downstream of the falls. Additional up-river observations beyond the study area were
conducted twice during the study period, after recreators at the lower falls departed for the evening, to see if additional recreators were present
on the river or riverbanks traveling downstream towards the falls ().
OBSERVATION LOG
OBSERVATION DAY 1
Date: Friday, July 14th, 2023
Start Time: River observations began @ 10:30 AM
Weather: Overcast, calm winds, warm
Location: Downriver of Nuyakuk Falls in boat, traveled approximately half mile downriver and observed from approximately 100 yards
downriver from the boat launch at the Portage Trail from 10:30 AM to 3:00 PM. Upriver of falls via boat from approximately 3:00 PM to 5:00
PM.
Lodges Present: Tikchik Narrows
Total Visitors Observed: 9 (assumed 7 clients, 2 guides)
A boat was tied up/parked near the lower falls Portage Trailhead – Shawn (bear guard) said it was a Royal Coachman boat they use
to get across the river to Grayling Beach after they boat in from their location upriver of the fall and hike the Portage Trail to the
lower falls.
Tikchik Lodge Beaver plane on floats inbound east to west at 10:35 AM, took off from river west to east at 10:45 AM
While traveling downriver, one boat passed traveling upriver with group of people and two recreators observed on south riverbank
11:00 AM boat returns after dropping off passengers at Grayling Beach (north riverbank just below the falls), picks up the two
recreators and shore to take to Grayling Beach
Group of 7 – two guides included- set up at Grayling Beach on north bank of the
lower river. One boat supported them and was tied to the alders. Group was
primarily fishing with rest and leisure all from the beach
People observed appeared to be all male, white and generally assumed to be above
55 years old
Fire was started on the beach
12:20 PM a white/light colored Beaver float plane flew south of river traveling east
206 Tikchik Lodge plan flew east to west over and around the falls @ 12:40 PM,
made a second pass in the same direction of travel to observe the falls and/or other
Tikchik recreators on Grayling Beach approximately 2 minutes later
Tikchik Lodge plan flew overhead west to east @ 1:25 PM
Tikchik boat with four people left Grayling Beach heading downriver @ 1:28/1:30
PM anticipated shift/location change for Lodge clients. Boat returned to the beach
get the remaining 3 people @ 1:39 PM and left at 1:48 PM
Tikchk plane left and returned to lower river to pick up clients between 1:40 PM and
2:15 PM
No other recreators were observed in the lower falls study area
No recreators were observed on the upper falls study area
OBSERVATION DAY 2
Date: Saturday, July 15th, 2023
Start Time: River observations began @ 10:00 AM
Weather: Heavy rain overnight and in the AM, partly cloudy and partly sunning in the afternoon to evening
Location: Downriver of Nuyakuk Falls on Grayling Beach
Total Visitors Observed: None.
No recreation observed: no people, no plane or boat activity within in or near the study area
Royal Coachman’s boat was not tied up and was not seen within the downriver study area.
OBSERVATION DAY 3
Date: Sunday, July 16th, 2023
Start Time: On-River observations @ 11:00 AM (intentionally give recreators unimpeded choice of set up location)
Weather: Overcast, calm winds, not raining, occasional drizzle/light rain in the afternoon
Location: Downriver of Nuyakuk Falls approximately 100 yards from boat launch
Lodges Present: Tikchik Narrows
Total Visitors Observed: 7 (assumed 5 clients, 2 guides)
Tikchik plane observed from camp flying west to east over falls/camp @ 8:57 AM and departing east to west over camp at 9:15 AM
Second Tikchik plan observed flying west to east south of camp @ (;43 AM and departing east to west at 10:17 AM
Tikchik Lodge had a group of 7 people fishing @ Grayling Beach
Two guides, possibly 1 female, and one female client (?)
Clients were more active and mobile than those observed on Friday, possibly younger in age
Fire was going on the shoreline
Tikchik Beaver plan flew west to east @11:46 AM, starting possible flight seeing and photography effort for a passenger in the plane
but cannot determine if that was the purpose (hazing us as we observed was discussed with our bear guard)
Looped back and flew over falls east to west within two minutes
Came over again east to west @ 11:58 AM low in elevation right over us in the boat
Looped again @ 12:01 PM, lower than previous pass
Looped again @ 12:09 PM but more south of river than previous passes
And again farther south of us and the river @ 12:16 PM
Bear guard/camp host said this isn’t an activity pattern he has seen during his time out here and they usually just do drop off and
pick ups of their clients/guides, not big sight seeing efforts
@ 12:30 PM the group at Grayling Beach begin a lunch break, ceased fishing and sat around the fire. Lunch finished around @2:00
PM and began fishing again
Boat with 4 clients and 1 guide left downriver @ 3:32 PM, 1 guide and 1 guest stayed on Grayling beach packing up gear.
Tikchik Beaver flying west to east south of the falls to pickup guests @ 4:04 PM, departs same flight path east to west @ 4:24 PM,
boat returns to get other client and guide
Tikchik Lodge guide driving the boat, named Will, came over to us in his boat and seemed happy to talk to us. He said he would pass
along the message about our desire to conduct surveys and checking email for the one we sent yesterday morning.
Boat picked up remaining people on Grayling beach and departed @4:36 PM
Tikchik plan returned @ 4:50 PM west to east, departing east to west @ 5:03 PM
In the evening, a plane was heard @ 10:30 PM (sunny skies) from inside the tent at camp – it did not sound close like other plans
heard/observed recreating at the falls so is assumed to be outside the study area.
OBSERVATION DAY 4
Date: Monday, July 17th, 2023
Start Time: On-River observations @ 9:40 AM
Weather: partly cloudy/partly sunny, calm winds, warm temps
Location: East terminus of Portage Trail and Downriver of Nuyakuk Falls approximately 100 yards from boat launch
Lodges Present: Royal Coachman, Tikchik Narrows
Total Visitors Observed: 9 (assumed 7 clients, 2 guides)
Tikchik Beaver plan observed flying west to east over camp to drop recreators off @ 8:03 AM, same plane departed east to west over
camp @ 8:17 AM
Upon arrival at the lower falls terminus of the Portage Trail, 3 fishermen observed in south eddy (“East Portage Pool”) actively
fishing in the water
o Royal Coachman – 1 guide, 2 clients both male above the age of 55
Tikchik fisherman observed @ Gayling Beach – 6 seen upon arrival, assumed to be 5 clients and 1 guide
Tikchik guests look to be all male over 55 years of age
Royal Coachman fishermen stopped fishing and existed the water @ 11:15 AM
We intercepted them and had the two clints take surveys
They walked west on the Portage Trail to their boat on the upper falls
Tikchik had a fire going when we moved from the shoreline at the Portage Trail out to our on water viewpoint approximately 100
yards south of the trail @ 11:33 PM
Tikchik group broke for lunch around noon and started packing up camp @ 1:15 PM
Tikchik boat took first trip of clients from Grayling Beach to their downriver pickup location @ 1:33 PM
We left our observation location and intercepted them at their boat launch where the clients agreed to take our survey
In conversation with the guide, he said “as long as you don’t build a dam, I’m happy” – his overall demeaner of our approach was
not positive
Beaver plan arrived for pickup @ 2:02 PM and took off at 2:12 PM and a second pickup and departure happened approximately 20
min later
Tikchik beaver flying west of the falls generally south to north/northwest @ 2:50 PM
Tikchik Plan observed from camp flying west to east south of the river and camp, farther than before in the day @ 4:00 PM
Plane activity heard in the distance from camp but not seen @ 4:45 PM
OBSERVATION DAY 5
Date: Tuesday, July 18th, 2023
Start Time: On-River observations @ 9:45 AM
Weather: Sunny, moderate winds, warm/hot temp in the 70s
Location: Downriver of Nuyakuk Falls approximately 100 yards from boat launch
Lodges Present: Tikchik Narrows
Total Visitors Observed: 3 (assumed 2 clients, 1 guide)
Tikchik beaver plane flew west to east just south of camp, dropping off people to fish lower falls @ 8:03 AM, returned east to west
over camp @ 8:19 AM
Coachman beaver plane flew west of camp @ 8:57 AM outside of study area traveling northwest
Tikchik lodge had 2 clients and 1 guide fishing @ Grayling beach when we moved to our on-water location
Clients appeared to be one male and one female above the age of 55 years old
They did not take a break for lunch and no fire was observed
Tikchik beaver plane flew over camp, south of the falls west to east, low @ 1:30 PM, anticipated a landing but did a loop, came in
south of river, landing @ 1:34 PM
Guide started passively packing up around 1:15 PM and was actively packing up after the plane’s first loop (it was the same guide as
the day before)
Fishermen left Grayling beach @ 1:40 PM, after the plane had landed, preventing us from intercepting them
Tikchik plane departed south of falls @ 1:54 PM, flew south of falls and camp
Left the lower river @ 2:00 PM, walking Portage Trail to upper river and boated the upper river looking for recreators till 4:00 PM
– no recreators were observed
Royal Coachman plane flew over camp, south of falls, east to west @ 5:25 PM
OBSERVATION DAY 6
Date: Wednesday, July 19th, 2023
Start Time: 9:50 AM
Weather: Sunny, no clouds, warm/hot with temps in the 70s
Location: East terminus of Portage Trail and Downriver of Nuyakuk Falls approximately 100 yards from boat launch
Lodges Present: Royal Coachman, Tikchik Narrows
Total Visitors Observed: 10 (assumed 6 clients, 4 guides)
Tikchik beaver plane flew over camp (south of the falls) @ 8:19 AM west to east, departed and flew over camp @ 8:37 AM
Royal Coachman plane observed flying east to west outside of study area, not over the falls or camp
Plane flying northeast to southeast came over the falls @ 9:30 AM (not directly over but in the vicinity of the falls), could not tell if it
was a Royal Coachman plane or not but it was not Tikchik
Royal Coachman has 2 clients and 2 guides actively fishing in the water in the south eddy (“East Portage Pool”)
o Guide said they arrived approximately 9:20 AM
o Turnover of clients is on Sundays
o They bring clients down to the lower falls almost every day this year as the weather hasn’t been good enough to fly, so this
week while the sun has been out they have been flying to other locations more
o They bring people down here to look at the falls, enjoy the scenery, take photos. It’s something they features as part of the
experience
o When the salmon aren’t running here, they will use the Portage Trail to get to their boats and run downriver to fish for
other species. They have moved their second boat to Arrow Creek (Shawn said this area has amazing hunting)
Tikchik Lodge group was fishing from Grayling Beach, possibly 4 guests and 2 guides
A small private jet flew south/over the falls at low elevation for assumed sight seeking @ 11:07 AM
Both Royal Coachman clients talked with us and took surveys
o One client said he doesn’t want to see this place changed
Royal Coachman existed and headed up the Portage Trail to go up river @ 12:15-12:30 PM
Tikchik broke for lunch about the same time that Coachman exited
Tikchik boat’s first trip with 2 clients departed Grayling Beach @ 1:42 PM , returned to get other clients and equipment @ 1:51 PM
Tikchik beaver plane arrived west to east for pickup @ 1:53 PM and second and final departure of clients from beach @ 1:56 PM
APPENDIX -:
Nushagak Cooperative Nuyakuk River Hydroelectric Project Recreation Study
Project Site Recreation Field Survey
About the Project
Welcome to the Nuyakuk River Falls (also known as Tikchik Falls). This survey is part of an ongoing study
of nearby natural, cultural, and recreational resources in support of Nushagak Electric and Telephone
Cooperative’s intent to construct and operate a proposed hydroelectric project and pursuant to study
requirements as determined by the Federal Energy Regulatory Commission (FERC). We would like to
hear about your visit to the Nuyakuk Falls, including your recreation activities and goals. Participation is
voluntary and all responses will be kept anonymous. A study report will be prepared by R&M
Consultants and made available to McMillen Corporation, Nushagak Cooperative, and FERC. If you have
any question about this survey, please contact Bryant Wright, 907-458-4307; bwright@rmconsult.com.
Trip Characteristics
1. Including yourself, how many people are you traveling with for your visit to the Nuyakuk River?
_______________ people
2. For how many days are you visiting this part of the Nuyakuk River? ________________ days
3. How many days is your trip to in total (from departing and returning home)? _____________ days
4. If staying multiple days near the Falls (within 2 miles), where are you staying overnight?
Check all that apply.
Campsite
Private lodging (personal, friend or family)
Private lodging (paid accommodation)
Other: ________________________________
5. Including this trip, how many times have you been to visit the Nuyakuk Falls? ___________ times
6. Is your visit part of a guided trip led by a hired, private guide or outfit? Yes No
If “Yes,” please provide the name of the company you hired:
____________________________________________ (Name of guide company, if applicable)
7. What was your primary method of accessing this area of the Nuyakuk River? Select one.
a. Bush Plane
b. Motorized boat
c. Paddling
d. OHV/ATV
e. Other _________________________________
8. Are you using or do you plan to use the Portage Trail? Yes No
9. If so, how are you using the portage trail around the falls? Please describe:
_______________________________________________________________________________
Nushagak Cooperative Nuyakuk River Hydroelectric Project Recreation Study
Project Site Recreation Field Survey
10. During your trip to the area, which of the following areas have you or do you plan do access?
Check all that apply.
Nuyakuk Falls: on the Nuyakuk River or adjacent land immediately surrounding the Falls
Lower Nuyakuk River (approximately ½ mile below or downstream of the Falls)
Upper Nuyakuk River (approximately ½ mile above or upstream of the Falls)
Tikchik Lake
Other _________________________________
Primary Activities
11. Please check each activity that you plan to participate in while visiting this area of Nuyakuk River:
Family social gatherings
Motorized Boating
Flying and Sightseeing
& Angling
(s): _________________________________________________________________________
12. From the activities marked above, which one would you select as your primary activity?
___________________________________________________
13. If hunting and/or fishing, what are species are you targeting? List all.
______________________________________________________________________________
______________________________________________________________________________
14. If hunting or fishing, which statement most strongly characterizes the purpose of your trip?
Select one.
a. I am hunting or fishing for sport or recreation.
b. I am hunting or fishing to feed myself and family and/or for income.
c. I am hunting or fishing equally for recreation and subsistence purposes.
15. On a scale of 1 to 5, (1 = not at all important and 5 = extremely important) how important were
the Nuyakuk Falls among other considerations when choosing your trip route or destination?
Level of Importance
Not at all -------------------- Somewhat --------------------- Extremely
1 2 3 4 5
Nushagak Cooperative Nuyakuk River Hydroelectric Project Recreation Study
Project Site Recreation Field Survey
Experiences &Benefits
16. When planning your trip, rate the importance you placed on achieving the following experiences.
Level of Importance
Not at all ------ Somewhat ------- Extremely
Enjoying the sights and smells of nature 1 2 3 4 5
Bringing your family close together 1 2 3 4 5
Experiencing new and different things 1 2 3 4 5
Testing your abilities 1 2 3 4 5
Being with friends 1 2 3 4 5
Growing and developing spiritually 1 2 3 4 5
Experiencing solitude 1 2 3 4 5
Teaching your outdoor skills to others 1 2 3 4 5
Taking a chance on dangerous situations 1 2 3 4 5
Getting away from the usual demands of life 1 2 3 4 5
Doing something creative such as sketching,
painting or taking photos
1 2 3 4 5
Getting exercise 1 2 3 4 5
Being free to make your own choices 1 2 3 4 5
Being away from crowds of people 1 2 3 4 5
17. We would like to know about the lasting benefits you hope to receive from your trip to this area of
the Nuyakuk River. Please indicate how desirable each of the following benefits were to you as an
outcome of this trip.
Personal benefits
Desirability to you
Not
at all
Low Moderate High
Very
high
Resting my mind from stress/tension/anxiety 1 2 3 4 5
Improving physical fitness 1 2 3 4 5
Improving/maintaining health 1 2 3 4 5
Improving outdoor knowledge 1 2 3 4 5
Developing self-reliance 1 2 3 4 5
Improving self-confidence 1 2 3 4 5
Living a more outdoor-oriented lifestyle 1 2 3 4 5
Strengthen ties with my family or friends 1 2 3 4 5
Closer relationship with natural world 1 2 3 4 5
Enhanced sense of personal freedom 1 2 3 4 5
Nushagak Cooperative Nuyakuk River Hydroelectric Project Recreation Study
Project Site Recreation Field Survey
Demographics
18. Are you currently an Alaska resident? Yes No
19. If yes, what is your community/town/village of residence?
______________________________________________________________________
20. What is your age in years? Select one.
a. Under 18
b. 18-24 years
c. 25-34 years
d. 35-44 years
e. 45-54 years
f. 55-64 years
g. 65 or older
21. To which gender to you most identify? Select one.
a. Female
b. Male
c. Transgender Male
d. Transgender Female
e. Gender Variant/Non-conforming
f. Other
g. Prefer not to disclose
22. Are you of Hispanic, Latino or Spanish origin? Yes No
23. How would you best describe your race? Select one.
a. Alaska Native or American Indian
b. Asian
c. Black or African American
d. Native Hawaiian or Other Pacific Islander
e. White
f. Prefer not to disclose
INITIAL STUDY REPORT
ATTACHMENT Q: ENVIRONMENTAL JUSTICE COMMUNITIES
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. i December 2023
TABLE OF CONTENTS
1.0 INTRODUCTION.............................................................................................................. 3
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 3
3.0 STUDY AREA................................................................................................................... 3
4.0 METHODOLOGY ............................................................................................................. 5
5.0 RESULTS........................................................................................................................... 7
6.0 DISCUSSION AND FINDINGS........................................................................................ 8
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 8
8.0 STUDY STATUS AND SCHEDULE................................................................................ 8
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 8
10.0 REFERENCES ................................................................................................................... 8
LIST OF FIGURES
Figure 3-1. Environmental Justice Communities Study Area .........................................................4
LIST OF TABLES
Table 4-1. Environmental Justice Data Table Example...................................................................5
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. ii December 2023
ACRONYMS AND ABBREVIATIONS
Commission Federal Energy Regulatory Commission
EJ Environmental Justice
EPA United States Environmental Protection Agency
FERC Federal Energy Regulatory Commission
NEPA National Environmental Policy Act
Project Nuyakuk River Hydroelectric Project (P-14873)
RSP Revised Study Plan
USR Updated Study Report
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 3 December 2023
1.0 STUDY PLAN INTRODUCTION
In accordance with the issuance of FERC’s Equity Action Plan (FERC, 2022), the Cooperative
proposed to conduct an Environmental Justice (EJ) Study to determine if development of the
proposed Project would affect communities that identify as environmental justice communities.
Depending on the location, design and operational specifications of certain projects, they may
affect human health or diminish the quality of life in environmental justice communities.
Examples of resource impacts may include, but are not necessarily limited to, project-related
effects on: subsistence fishing, hunting, or plant gathering; access for recreation; industries of
importance to environmental justice communities; and construction-or operation-related air
quality, noise, and traffic.
2.0 STUDY GOALS AND OBJECTIVES
The EJ Study has five objectives:
1) to identify presence of environmental justice communities that may be affected by
the licensing of the Project, including the construction of the Project, and identify
outreach strategies to engage the identified environmental justice communities in
the licensing process, if present;
2) to identify the presence of non-English speaking populations that may be affected
by the Project and identify outreach strategies to engage non-English speaking
populations in the licensing process, if present;
3) to discuss effects of licensing the Project on any identified environmental justice
communities and recognize any effects that are disproportionately high and
adverse;
4) to identify mitigation measures and avoid or minimize project effects on
environmental-justice communities; and
5) to identify sensitive receptor locations within the Project area and identify
potential effects as well as measures taken to avoid or minimize these effects (if
present).
3.0 STUDY AREA
The Cooperative proposed to study potential Project impacts on environmental justice
communities within 5 miles of the proposed Project boundary, including any potential impacts
associated with transmission upgrades (Figure 3-1).
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 4 December 2023
Figure 3-1. Environmental Justice Communities Study Area
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 5 December 2023
4.0 METHODOLOGY
The Cooperative will use the methodology that FERC recommends for collecting environmental
justice data for hydroelectric projects. This methodology has been successfully employed on a
number of projects in the licensing process and is consistent with guidance from the
Environmental Protection Agency’s Promising Practices for EJ Methodologies in NEPA
Reviews (EPA 2016). The Cooperative will provide the following:
a) A table of racial, ethnic, and poverty statistics for each state, borough, native regional
corporation, and census blockgroup (may only exist for census tract)within thegeographic
scope of analysis. For the Project, the geographic scope of analysis is all areas within 5
miles of the proposed Project boundary. The table will include the following information
from the U.S. Census Bureau’s most recently available American Community Survey 5-
Year Estimates for each state, native regional corporation, borough, and block group
(wholly or partially) within the geographic scope of analysis:
a. Total population;
b. Total population of each racial and ethnic group (i.e., White Alone Not Hispanic,
Black or African American, American Indian and Alaska Native, Asian, Native
Hawaiian and Other Pacific Islander, some other race, two or more races, Hispanic
or Latino origin [of any race]) (count for each group);
c. Minority population including individuals of Hispanic or Latino origin as a
percentage of total population;1 and
d. Total population below poverty level as a percentage.
2
The data will be collected from the most recent American Community Survey files available, using
table #B03002 for race and ethnicity data and table #B17017 for low- income households. An
example table is provided below (Table 4-1).
Table 4-1. Environmental Justice Data Table Example.
1 To calculate the percent total minority population, subtract the percentage of “White Alone Not Hispanic”
from 100 percent for any given area.
2 To calculate percentage of total population below poverty level, divide the total households below the
poverty level by the total number of households and multiply by 100.
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 6 December 2023
b) Identification of environmental justice populations by block group, using the data obtained
in response to part a above, by applying the following methods included in EPA’s
Promising Practices for EJ Methodologies in NEPA Reviews (2016).
i. To identify environmental justice communities based on the presence of
minority populations, the Cooperative will use the “50-percent” and the
“meaningfully greater” analysis methods. To use the “50-percent” analysis
method, the Cooperative will determine whether the total percent minority
population of any block group in the affected area exceeds 50-percent. To use
the “meaningfully greater” analysis, the Cooperative will determine whether
any affected block group affected is 10-percent greater than the minority
population percent in the native regional corporation using the following
process:
1. Calculate the percent minority in the reference population (native
regional corporation);
2. To the reference population’s percent minority, add 10-percent (i.e.,
multiply the percent minority in the reference population by 1.1); and
3. This new percentage is the threshold that a block group’s percent
minority would need to exceed to qualify as an environmental justice
community under the meaningfully greater analysis method.
ii. To identify environmental justice communities based on the presence of low-
income populations, use the “low-income threshold criteria” method. To use
the “low-income threshold criteria,” the percent of the population below the
poverty level in the identified block group must be equal to or greater than
that of the reference population (native regional corporation).
c) A map showing the Project boundary and location(s) of any proposed Project- related
construction in relation to any identified environmental justice communities within the
geographic scope. Denote on the map if the block group is identified as an environmental
justice community based on the presence of minority population, low-income population,
or both.
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 7 December 2023
d) A discussion of anticipated Project-related effects on any environmental justice
communities for all resources where there is a potential nexus between the effect and the
environmental justice community. For any identified effects, the Cooperative will also
describe whether or not any of the effects would be disproportionately high and adverse.
e) If environmental justice communities are present, the Cooperative will provide a
description of public outreach efforts regarding the Project, including:
i. a summary of any outreach to environmental justice communities conducted
prior to filing the application (include the date, time, and location of any
public meetings beyond those required by the regulations);
ii. a summary of comments received from members of environmental justice
communities or organizations representing the communities;
iii. a description of information provided to environmental justice communities;
and
iii. planned future outreach activities and methods specific to working with the
identified communities.
f) A description of any mitigation measures proposed to avoid and/or minimize Project
effects on environmental justice communities.
g) Identification of any non-English speaking groups, within the geographic scope of
analysis, that would be affected by the Project (regardless of whether the group is part of
an identified environmental justice community). The Cooperative will describe previous
and planned efforts to identify and communicate with these non-English speaking groups
and identify and describe any measures that proposed to avoid and minimize any Project-
related effects non-English speaking groups.
h) Because new construction is proposed, identification of sensitive receptor locations (e.g.,
schools, day care centers, hospitals, etc.) will be included within the geographic scope of
analysis. The Cooperative will show these locations on the map generated in step c. In the
study report, the Cooperative will provide a table that includes their distances from
Project facilities and any Project-related effects on these locations, including measures
taken to avoid or minimize Project-related effects.
5.0 RESULTS
Data collection and analysis for this study has not been completed. Initial datasets from the
American Community Survey have been obtained from publicly available sources but have not
yet been compiled and analyzed. Additional data collection, including identification of non-
English speaking groups and sensitive receptor locations have not been initiated. The
Nuyakuk River Hydroelectric Project Environmental Justice Communities
FERC No. 14873 Initial Study Report – Attachment Q
Nushagak Cooperative, Inc. 8 December 2023
methodology described in Section 4.0 will be utilized in 2024 and results will be reported in the
Project’s Updated Study Report (USR) in December 2024.
6.0 DISCUSSION AND FINDINGS
Study results will be summarized and discussed in December of 2024 when the USR is due to be
filed with FERC following Year 2 of the Study Program. The status of EJ Communities study
will be presented and collaboratively discussed with stakeholders during the ISR meeting in
December of 2023.
7.0 STUDY VARIANCES AND MODIFICATIONS
There were no variances or modifications to the EJ Communities study plan.
8.0 STUDY STATUS AND SCHEDULE
The majority of the EJ Communities study will occur in 2024. Study results will be reported in
the Project’s USR in December 2024.
9.0 STUDY-SPECIFIC CONSULTATION
Additional agency consultation was not necessary to initiate data collection from public sources.
Consultation with regional entities and Tribes will occur in 2024 in association with recreational
surveys. These supplemental outreach efforts will identify sensitive receptor locations within the
study area.
10.0 REFERENCES
Environmental Protection Agency (EPA). 2016. Promising Practices for EJ Methodologies in
NEPA Reviews. March 2016. Available online at:
https://www.epa.gov/sites/default/files/2016-
08/documents/nepa_promising_practices_document_2016.pdf.
INITIAL STUDY REPORT
ATTACHMENT R: DECISION SUPPORT TOOL
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. ii December 2023
TABLE OF CONTENTS
1.0 STUDY PLAN INTRODUCTION..................................................................................... 1
2.0 STUDY GOALS AND OBJECTIVES............................................................................... 1
3.0 STUDY AREA................................................................................................................... 1
4.0 METHODOLOGY ............................................................................................................. 1
4.1 eDST Methodology................................................................................................. 2
4.1.1 Assumptions Worksheet ............................................................................. 2
4.1.2 Rate Based Model ....................................................................................... 3
5.0 RESULTS ........................................................................................................................... 5
6.0 DISCUSSION AND FINDINGS........................................................................................ 6
7.0 STUDY VARIANCES AND MODIFICATIONS............................................................. 6
8.0 STUDY STATUS AND SCHEDULE................................................................................ 6
9.0 STUDY-SPECIFIC CONSULTATION ............................................................................. 6
10.0 REFERENCES ................................................................................................................... 6
LIST OF FIGURES
Figure 4-1. Example GUI output. ....................................................................................................5
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. iii December 2023
ACRONYMS AND ABBREVIATIONS
ARWG Aquatics Resources Working Group
Cooperative Nushagak Electric & Telephone Cooperative
eDST economic Decision Support Tool
Falls Nuyakuk Falls
FERC Federal Energy Regulatory Commission
GUI Graphical Unit Interface
ISR Initial Study Report
kWh kilowatt hours
Project Nuyakuk River Hydroelectric Project (P-14873)
USR Updated Study Report
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 1 December 2023
1.0 STUDY PLAN INTRODUCTION
Because of the Cooperative’s desire to evaluate the feasibility of this Project from all
perspectives, the Cooperative elected to develop an economic analysis tool that will assist in
informing the potential economic impact of the project (positive and negative) over the duration
of its operations. To date, an abundance of collaboration with the Aquatics Resources Working
Group (ARWG) and its associated work on the Life Cycle Model will allow for the two to
inform each other and create a comprehensive tool through which, a variety of operational and
natural resource scenarios can be run.
2.0 STUDY GOALS AND OBJECTIVES
The economic analysis tool, hereafter referred to as the economic Decision Support Tool or
eDST, considers both: 1) economic impact of developing the run-of-river hydropower project
and the impact on the Sockeye and Chinook fisheries, and 2) an electricity base rate model
allows the Cooperative to explore different cost differentials between current diesel generation
and with the run-of-river with diesel backup approach. The eDST will accept information from
the river flow/climate model in terms of the impact over the 50-year life of the run-of-river hydro
generation system, the powerhouse model and the aquatic fisheries lifecycle model to capture the
economic impact from changes in sport fishing and commercial fishing. Subsistence fishing and
escapement are constrained to be unaffected by the run of the river hydropower project.
3.0 STUDY AREA
The Project will be on the Nuyakuk river, a tributary to the Nushagak River. From the Project
site, the Nuyakuk River runs approximately 40 miles before converging with the Nushagak
River, which continues to Bristol Bay. Therefore, the economic analysis focuses on economic
values specific to the Nuyakuk. Specifically, the eDST focuses on the Chinook and Sockeye
species to be consistent with the life cycle model analyses for this area. The model also includes
the geographic scope of the transmission lines to move the power to the load centers.
4.0 METHODOLOGY
The eDST spreadsheet tool (i.e., engine) contains a number of spreadsheets. The most important
sheets are the Read Me, Assumptions, Annual Diesel and Hydro Costs, Diesel and Hydro
Monthly, Fisheries – Annual, and River flow Worksheets. There are also several background
sheets with information that drive the data within the model, and include data provided by the
Cooperative such as Diesel Generator Costs, Diesel Other Production Costs, Diesel Loan
Amortization, Diesel Depreciation, Overhaul Cost Comparisons, Demand Assumptions, Hydro
Assumptions, River flow, and Administration. Most of the vital information has been moved to
the Assumptions worksheet.
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 2 December 2023
4.1 eDST Methodology
4.1.1 Assumptions Worksheet
The Assumption worksheet drives the economic impact and the electricity rate making analyses.
The worksheet contains input cells (in yellow) that drive consumption by community and the
start date for each community. There is a section for assumptions about diesel generation costs
along with various options and opportunities to adjust assumptions especially fuel cost values
used in the analyses. The worksheet also has assumptions to drive the river flow calculations
which are driven by the sliders in the user interface, such as the diversion limits per month, the
baseline river flow values by month in cubic feet per second, and the flow rate of change
associated with climate change. There is a section with assumptions for the powerhouse
construction costs along with the additional transmission costs associated with the Project and
the Project spend plan. Another section provides assumptions for Project operations including
operations interest rates, internal powerhouse consumption, and repairs. A section on other costs
includes Operating Margin and G&A as well as the BCA period and Economic Impact
Multipliers. There is a section for the assumption about baseline fisheries for Sockeye and
Chinook. The following subsection provides more detail on the assumptions section.
4.1.1.1 Assumptions Sections
There are various inputs into the eDST, including diesel and hydropower costs, retail electricity
consumption, river flow, and fish numbers. Hydropower generation, river flow and fish numbers
will all be provided to the eDST output from other the river flow, life-cycle and power
generation models. The model currently has worksheets for those model outputs to be provided
as inputs to the eDST.
Economic Costs:
Diesel generation costs were provided by the Cooperative. Related breakdowns for labor,
maintenance, and administrative are captured in the calculations. Inputs related to powerhouse
consumption, line losses, etc. that contribute to total required generation calculations are also
captured. Project costs include construction spend plan (e.g., equipment, labor, and permitting)
and operational period estimates (e.g., insurance rates, taxes, and repairs). Other inputs within
the eDST capture estimated grant numbers and general overhead.
Electricity Demand:
Community electricity consumption values (in kWh) are included in the eDST. Values for
Dillingham and Aleknagik provided by the Cooperative are incorporated into the eDST, and
placeholders for other community consumption data (e.g., Koliganek, Ekwok/New Stuyahok,
and Levelock) can be used/updated as needed. The growth rate for the communities can be
adjusted in the User Interface.
River Flow Values:
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 3 December 2023
Currently, monthly river flow values for the Nuyakuk River above the Project are available from
1953 to present. Summary values based on this historical record are used as inputs in the eDST.
Annual changes to river flow currently use climate change projections from Wobus et al. (2015)
to reflect future changes expected in the area. These values will be changed based on insights
from the hydro/climate model.
Fish Values:
Escapement values for the Nuyakuk were recorded using tower data from 2003 through 2006.
More recent values will be estimated by back-calculating proportions based on Nushagak
escapement values. Other key input in the eDST are the relative proportion of Sockeye and
Chinook from the Nuyakak that contribute to commercial, sport, subsistence, and escapement
activities. Currently, placeholder values are used in the eDST, but require review and update.
4.1.2 Rate Based Model
The Diesel and Hydro monthly worksheet contains the baseline diesel model and the run-of-river
Project model. The diesel baseline is driven primarily by the electricity consumption of
Dillingham and the five villages. Generation is calculated by adding back distribution losses and
diesel powerhouse consumption costs. Costs are driven by diesel fuel, labor, and repairs. Costs
that are not driven by monthly operations are only included in Annual Diesel and Hydro Costs
worksheet. The monthly model feeds an annual summary worksheet which feeds the output of
the economic model.
The Project calculates electricity production based on the river flow assumed by month and
allowed diversion. If hydro generation doesn’t meet consumption needs, the diesel generators
feed the rest of consumption. (NETC has the region’s most efficient diesel plant to feed all of the
connected communities even if the Coop reverts to diesel.) Run-of-river electricity generation
removes the consumption of the powerhouse before determining if the diesel generators need to
be turned on. Diesel generation, if needed, requires remaining consumption be met and adds on
distribution losses and diesel powerhouse consumption to determine total generation. Costs for
diesel generation are based on fuel costs, repairs, amortization of new diesel generator loans, and
other production costs which are primarily based on labor. The hydro model is primarily based
on amortization of the loans on the powerhouse and transmission lines along with fixed and
variable operation and maintenance and other production costs.
The Annual Diesel and Hydro Costs worksheet summarizes the annual costs in the monthly
worksheet and adds costs like G&A and Operating Margin. The Annual Diesel and Hydro Costs
are summarized into two different types: Cash and Net Operating Costs. The cash outlays
indicate the costs the Cooperative are incurring during a year while the Net Operating Costs
smooths out the Cash Costs with depreciation of the powerhouse and amortization of major
overhauls for both the Diesel and Hydro. Major hydro repairs are amortized over 13 years, Major
Diesel Overhauls occurs over three years and minor diesel overhauls occur over 18 months. The
Net Operating Margin would be basis for rate making for the Cooperative.
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 4 December 2023
The River Flow worksheet provides a space for inputs from the Hydrology Model. Currently, it
is based on the average river flow in each month and the change in river flow by month based on
a climate change model. The idea is the output of the future river flow model can be put into this
sheet and the output of the sheet can be put into the monthly hydro and diesel worksheet.
The Fisheries worksheet provides an annual breakdown for both Sockeye and Chinook based on
assumptions about the initial fish entering the Nuyakuk. For each species, the worksheet
indicates how much of the annual fishery is taken by commercial and sport fishing. The
assumption is that subsistence fishing and escapement will be largely unaffected. There is a
separate section for the baseline and one for the impact of implementing the Project. The eDST
assumes that subsistence fishing will not be impacted because the escapement from the Project
will be designed to ensure adequate flow that protect these needs.
eDST Graphical User Interface:
To facilitate exploration of these scenarios, a front-end graphical user interface (GUI) will be
developed. Specifically, the GUI will enable the users to select between different climate
conditions, economic costs, and diversion limits. These inputs would then be read into the eDST
engine and the associated outputs from the latter would then be visualized within the GUI (see
mock-up image below; Figure 4-1). We anticipate building the GUI using the RShiny applet
capabilities within R, an open-source software.
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 5 December 2023
Figure 4-1. Example GUI output.
During the construction of the eDST, sensitivity analyses can also be run through the eDST to
ensure that the economic outputs function across expected ranges (of fish, river flows, etc.).
More importantly, the GUI would allow stakeholders to evaluate the impact of different
assumptions that will change outputs. Final selection of relevant outputs to visualize will be done
in collaboration with the stakeholders. The RShiny code can be easily updated to reflect
stakeholder priorities. The input sheets for the Hydrology Model, the Power Model and the Life
Cycle Model feed the Rate Based Model which feeds economic worksheet which provides a
Benefit Cost Analysis of each scenario evaluated.
5.0 RESULTS
At the time of this writing there are no results from the eDST as no new input values have been
provided to the eDST. Continued integration with the other relevant models will take place
during the remainder of 2023 and the 2024 study seasons. Results and analysis will be reported
on in the Updated Study Report (USR).
Nuyakuk River Hydroelectric Project Decision Support Tool
FERC No. 14873 Initial Study Report – Attachment R
Nushagak Cooperative, Inc. 6 December 2023
6.0 DISCUSSION AND FINDINGS
Continued integration with the other relevant models will take place during the remainder of
2023 and the 2024 study seasons. Results and analysis will be reported on in the USR.
7.0 STUDY VARIANCES AND MODIFICATIONS
No study variances have been identified at this time. Continued integration with the other
relevant models will take place during the remainder of 2023 and the 2024 study seasons.
Results and analysis will be reported on in the USR.
8.0 STUDY STATUS AND SCHEDULE
Continued integration with the other relevant models will take place during the remainder of
2023 and the 2024 study seasons. Results and analysis will be reported on in the USR.
9.0 STUDY-SPECIFIC CONSULTATION
Consultation specifically associated with the eDST and the ARWG has taken place on a bi-
monthly basis and as needed over the course of the past 18 months. It is anticipated that
continued ARWG dialogue will occur throughout the remainder of 2023 and the 2024 study
seasons.
10.0 REFERENCES
Wobus, C., R. Prucha, D. Albert, C. Woll, M. Lionaz, R. Jones. 2015. Hydrologic alterations
from climate change inform assessment of ecological risk to pacific salmon in Bristol
Bay, Alaska. PLoS ONE 10(12): e0143905. doi:10.1371/journal.pone.0143905.
INITIAL STUDY REPORT
ATTACHMENT S: AESTHETIC STUDY
NUYAKUK RIVER HYDROELECTRIC PROJECT
FERC NO. 14873
Submitted by:
Nushagak Electric & Telephone Cooperative, Inc.
P.O. Box 350
Dillingham, AK 99576
December 2023
Nuyakuk River Hydroelectric Project Aesthetic Study
FERC No. 14873 Initial Study Report – Attachment S
Nushagak Cooperative, Inc. December 2023
AESTHETIC STUDY UPDATE
The Aesthetic Study will be implemented in 2024 as described in the Federal Energy Regulatory
Commission’s (FERC’s) Study Plan Determination. Data gathered and renderings created for the
Aesthetic Study will be analyzed and reported on in the Updated Study Report (USR), along with
an assessment of potential impacts associated with Project development and operations. The
USR will be filed with FERC no later than December 1, 2024.