[Federal Register Volume 90, Number 158 (Tuesday, August 19, 2025)]
[Proposed Rules]
[Pages 40492-40528]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-15775]
[[Page 40491]]
Vol. 90
Tuesday,
No. 158
August 19, 2025
Part III
Department of Commerce
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National Oceanic and Atmospheric Administration
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50 CFR Part 217
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to the Interstate Bridge Replacement Project
on Interstate 5 Between Portland, Oregon and Vancouver, WA; Proposed
Rule
Federal Register / Vol. 90, No. 158 / Tuesday, August 19, 2025 /
Proposed Rules
[[Page 40492]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 250814-0142]
RIN 0648-BN34
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Interstate Bridge Replacement
Project on Interstate 5 Between Portland, Oregon and Vancouver, WA
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
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SUMMARY: Interstate Bridge Replacement Program (IBRP) applied for
authorization to take small numbers of marine mammals incidental to the
Interstate Bridge Replacement Project (IBR) on Interstate 5 (I-5)
between Portland, Oregon, and Vancouver, Washington over the course of
5 years from the date of issuance. Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is proposing regulations setting forth
permissible methods of taking, other means of effecting the least
practicable adverse impact on such marine mammal stocks (i.e.,
mitigation measures), and requirements pertaining to monitoring and
reporting such takes and requests comments on the proposed regulations.
NMFS will consider public comments prior to making any final decision
on the promulgation of the requested MMPA regulations, and NMFS's
responses to public comments will be summarized in the final notice of
our decision.
DATES: Comments and information must be received no later than
September 18, 2025.
ADDRESSES: A plain language summary of this proposed rule is available
athttps://www.regulations.gov/docket/NOAA-NMFS-2025-0273. You may
submit comments on this document, identified by NOAA-NMFS-2025-0273, by
any of the following methods:
Electronic Submission: Submit all electronic public
comments via the Federal e-Rulemaking Portal. Go to https://www.regulations.gov and type NOAA-NMFS-2025-0273 in the Search box
(note: copying and pasting the FDMS Docket Number directly from this
document may not yield search results). Click on the ``Comment'' icon,
complete the required fields, and enter or attach your comments.
Mail: Submit written comments to: Permits and Conservation
Division, Office of Protected Resources, 1315 East-West Highway, F/PR1
Room 13805, Silver Spring, MD 20910.
Instructions: Comments sent by any other method, to any other
address or individual, or received after the end of the comment period,
may not be considered by NMFS. All comments received are a part of the
public record and will generally be posted for public viewing on
https://www.regulations.gov without change. All personal identifying
information (e.g., name, address, etc.), confidential business
information, or otherwise sensitive information submitted voluntarily
by the sender will be publicly accessible. NMFS will accept anonymous
comments (enter ``N/A'' in the required fields if you wish to remain
anonymous).
Electronic copies of the application and supporting documents, as
well as a list of the references cited in this document, may be
obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-interstate-bridge-replacement-programs-interstate-bridge. In case of problems accessing these documents, please call the
contact listed below.
FOR FURTHER INFORMATION CONTACT: Cara Hotchkin, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose of Regulatory Action
These proposed regulations, promulgated under the authority of the
MMPA (16 U.S.C. 1361 et seq.), would provide a framework for
authorizing the take of marine mammals incidental to construction
activities associated with the IBR project, including impact and
vibratory pile driving.
NMFS received an application from the IBRP requesting 5-year
regulations and a letter of authorization issued thereunder to take
individuals of three species, comprising three stocks of marine mammals
by Level A harassment and Level B harassment incidental to the IBRP's
activities. No serious injury or mortality is anticipated or proposed
for authorization. Please see Background below for definitions of
harassment.
The proposed regulations include mitigation, monitoring, and
reporting requirements. These requirements, which were proposed by
IBRP, are expected to minimize the number and/or intensity of incidents
of marine mammal take, as well as to provide information to better
understand the impacts of the action and document compliance. IBRP has
agreed that all of the mitigation measures are practicable. As required
by the MMPA, NMFS concurred that these measures are sufficient to
achieve the least practicable adverse impact on the affected marine
mammal species or stocks and their habitat.
Legal Authority for the Proposed Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs
the Secretary of Commerce to allow, upon request, the incidental, but
not intentional taking of small numbers of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region for up to 5 years if,
after notice and public comment, the agency makes certain findings and
promulgates regulations that set forth permissible methods of taking
pursuant to that activity and other means of effecting the ``least
practicable adverse impact'' on the affected species or stocks and
their habitat (see the discussion below in the Proposed Mitigation
section), as well as monitoring and reporting requirements. Section
101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR
part 216, subpart I provide the legal basis for issuing this proposed
rule containing 5-year regulations and for any subsequent letters of
authorization (LOAs).
Summary of Major Provisions Within the Proposed Rule
Following is a summary of the major provisions of this proposed
rule regarding the IBRP's activities. These measures include:
Prescribing permissible methods of taking of small numbers
of marine mammals by Level A harassment and/or Level B harassment
incidental to the IBR project;
Required monitoring of the construction areas to detect
the presence of marine mammals before beginning construction
activities;
Establishment of shutdown zones;
Bubble curtains required for impact driving of steel piles
except as necessary to verify bubble curtain effectiveness during
hydroacoustic monitoring;
Soft start for impact pile driving to allow marine mammals
the opportunity to leave the area prior to beginning impact pile
driving at full power;
Submittal of monitoring reports including a summary of
marine mammal species and behavioral observations, construction
shutdowns or delays, and construction work completed; and
[[Page 40493]]
Hydroacoustic monitoring to verify effectiveness of noise
attenuation devices and sound source level assumptions for modeling.
Through adaptive management, the proposed regulations would allow
NMFS Office of Protected Resources to modify (e.g., remove, revise, or
add to) the existing mitigation, monitoring, or reporting measures
summarized above and required by the LOA.
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et
seq.) directs the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of incidental
take regulations and an LOA) with respect to potential impacts on the
human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (ITAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has preliminarily determined
that the issuance of the proposed LOA qualifies to be categorically
excluded from further NEPA review.
Fixing America's Surface Transportation Act
This project is covered under Title 41 of the Fixing America's
Surface Transportation Act, or ``FAST-41.'' FAST-41 includes a suite of
provisions designed to expedite the environmental review for covered
infrastructure projects, including enhanced interagency coordination as
well as milestone tracking on the public-facing Permitting Dashboard.
FAST-41 also places a 2-year limitations period on any judicial claim
that challenges the validity of a Federal agency decision to issue or
deny an authorization for a FAST-41 covered project. 42 U.S.C. 4370m-
6(a)(1)(A).
Summary of Request
On July 18, 2024, NMFS received application from the IBRP
requesting authorization for take of marine mammals incidental to
construction activities related to the IBR project on I-5 between
Portland, OR and Vancouver, WA. After the IBRP responded to our
questions on October 12, 2024, and January 14, 2025, we determined the
application was adequate and complete on January 16, 2025. We published
a notice of receipt (NOR) in the Federal Register on March 13, 2025 (90
FR 11950, March 13, 2025) and received 38 comments. Of these, 37 were
opposed to the IBR project; most suggested an alternative project
design unrelated to IBRP's request for incidental take authorization.
Commenters additionally expressed concern about the cost of the project
and described potential issues with the IBRP's supplemental
environmental impact statement. One comment letter expressed support
for the IBR project and the potential associated increases in
employment and training opportunities for ironworkers. NMFS determined
that these comments did not provide information relevant to our
decision under the MMPA.
The requested regulations would be valid for 5 years, from
September 15, 2027, through September 14, 2032. The IBRP plans to
conduct necessary work, including pile driving (impact and vibratory)
and rotary drilling, to construct replacement bridges for the I-5
roadway over the Columbia River and North Portland Harbor. The proposed
action may incidentally expose marine mammals occurring in the vicinity
to elevated levels of underwater sound, thereby resulting in incidental
take by Level A and Level B harassment. Therefore, the IBRP requests
authorization to incidentally take harbor seals (Phoca vitulina),
California sea lions (Zalophus californianus), and Steller sea lions
(Eumetopias jubatus). Neither IBRP nor NMFS expect serious injury or
mortality to result from this activity.
These proposed incidental take regulations would cover 5 years of a
larger project for which IBRP intends to request take authorization for
subsequent facets of the project. The larger 9- to 15-year project
involves full construction of new bridges over both the Columbia River
and the North Portland Harbor, and the demolition and removal of the
existing bridges.
Description of Proposed Activity
Overview
The IBR project would improve I-5 corridor mobility by addressing
present and future travel demand and mobility needs in the project
area. The project consists of multiple components and interchanges,
extending from approximately Columbia Boulevard in the south to State
Route (SR) 500 in the north; one component of the project is to replace
the existing bridges over the Columbia River and North Portland Harbor
to accommodate increasing travel demand and congestion, improve safety
related to traffic accidents, and reduce vulnerability to seismic
events. The existing bridges do not meet current seismic standards, and
are vulnerable to failure in an earthquake. The IBR project is
anticipated to take approximately 9 to 15 years to complete, and would
require in-water work in up to 9 construction seasons. If promulgated,
the regulations would be effective for the first 5 construction years
(2027--2032). IBRP anticipates requesting additional, future incidental
take authorizations as necessary in association with subsequent years
of construction.
Exact project sequencing is still in development; however, it is
currently anticipated that work to be conducted during the first 5
years of the IBR project would include construction of the new Columbia
River Bridge and associated approaches, and the transit bridge crossing
the North Portland Harbor. In-water pile driving for the first 5
[[Page 40494]]
construction years would include both impact and vibratory driving of
temporary steel pipe (24-inch (in) (0.61 meters (m)) and 48-in (1.2 m)
diameter) and steel sheet piles. Permanent bridge foundations would be
constructed using 10-foot (ft) (3-m) diameter steel casings installed
with an oscillator, analogous to a rotary drill. Impact driving would
be conducted primarily with the use of a bubble curtain, with a minimal
amount of unattenuated driving to confirm bubble curtain effectiveness.
(Note that IBRP's plans to use bubble curtains are primarily related to
concerns regarding potential effects to fishes, but would also be
protective to marine mammals.) In-water pile driving associated with
the project would include installation and potential removal of
approximately 1,560 temporary steel pipe piles, and 1,500 linear ft
(457 m) of steel sheet piles over the 5-year period.
Dates and Duration
IBRP anticipates that in-water construction activities associated
with this project would begin on September 15, 2027, and extend through
September 14, 2032. In-water pile installation for the first 5 years of
the IBR project is expected to occur on approximately 1,725 non-
consecutive days. While the exact project design and sequence of
construction are not yet finalized, project elements and estimated
durations are shown in table 1. Construction timing, sequencing, and
duration are dependent on funding, design assumptions, contractor
schedules and equipment, and weather, among other factors. The duration
estimates shown are based on the best available information at the time
of publication.
Table 1--Project Elements, Locations and Estimated Durations for the IBR Project
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Project element Estimated duration Element location Notes
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Columbia River bridges......... 4 to 7 years............... In-water.................. Construction is likely
to begin with the
main river bridges.
General sequence will
include initial
preparation and
installation of
foundation piles,
shaft caps, pier
columns,
superstructure, and
deck.
North Portland Harbor bridges.. 4 to 10 years.............. In-water.................. Construction duration
for North Portland
Harbor bridges is
expected to be
similar to the
duration for Hayden
Island Interchange
construction. The
existing North
Portland Harbor
bridge will be
demolished in phases
to accommodate
traffic during
construction of the
new bridges.
Hayden Island interchange...... 4 to 10 years.............. Land-based................ Interchange
construction duration
will not necessarily
entail continuous
active construction.
Hayden Island work
could be broken into
several contracts,
which could spread
work over a longer
duration.
Marine Drive interchange....... 4 to 6 years............... Land-based................ Construction will need
to be coordinated
with construction of
the North Portland
Harbor bridges.
SR 14 interchange.............. 4 to 6 years............... Land-based................ Interchange will be
partially constructed
before any traffic
could be transferred
to the new Columbia
River bridges.
Demolition of the existing 1.5 to 3 years............. In-water.................. Demolition of the
Interstate Bridge. existing Interstate
Bridge could begin
only after traffic is
rerouted to the new
Columbia River
bridges.
Three interchanges north of SR 3 to 4 years for all three. Land-based................ Construction of these
14. interchanges could be
independent from each
other and from
construction of the
Program components to
the south.
Light-rail..................... 4 to 6 years............... Over-water................ The light-rail
crossing will be
built with the
Columbia River
bridges. This phase
includes all the
infrastructure
associated with LRT
(e.g., overhead
catenary system,
tracks, stations, and
park and rides).
----------------------------------------------------------------------------------------------------------------
Impact driving would be restricted to an in-water work window
between September 15 and April 15 of each year. This window was
determined via coordination with state (Oregon Department of Fish and
Wildlife [ODFW] and Washington Department of Fish and Wildlife [WDFW])
and Federal (U.S. Army Corps of Engineers [USACE], Federal Highway
Administration, Federal Transit Administration, and NMFS) agencies,
Tribal parties, and public input to reduce potential impacts to
Endangered Species Act (ESA)-listed fishes. Vibratory pile driving
would occur year-round.
Specific Geographic Region
The IBR project will replace the bridge spans across the Columbia
River and North Portland Harbor and the associated highway interchanges
on an approximately 5-mile (mi) (8 kilometer [km]) stretch of I-5
between Portland, OR and Vancouver, WA (figure 1). In-water work will
occur in the subset of the project area between the north bank of the
Columbia River in Washington and the south shore of the North Portland
Harbor in Oregon, between river miles 106 and 107. The widths of the
Columbia River and North Portland Harbor at this location are
approximately 0.5 mi (841 m) and 0.18 mi (295 m), respectively.
BILLING CODE 3510-22-P
[[Page 40495]]
[GRAPHIC] [TIFF OMITTED] TP19AU25.000
BILLING CODE 3510-22-C
Figure 1--Overview of IBR Project Location Along I-5 Between Portland,
OR and Vancouver, WA
Detailed Description of the Specified Activity
The IBRP proposes to replace the existing I-5 crossings of the
Columbia River and North Portland Harbor and associated interchanges to
improve safety and traffic flow, and to reduce seismic vulnerabilities.
A previous iteration of this project, called the Columbia River
Crossing (CRC) project, was considered between 2005 and 2013 (77 FR
23548, April 19, 2012) and discontinued in 2014. The IBRP is a bi-state
governmental committee formed in 2019 dedicated to improving the I-5
corridor between Washington and Oregon; it is made up of
representatives from both the Washington and Oregon Departments of
Transportation, in collaboration with representatives from eight
partner agencies. The IBRP utilized the results of the CRC analyses to
inform project planning, design, and preconstruction activities for
this project. The IBR project is expected to take approximately 9 to 15
years, with up to 9 in-water construction seasons.
The IBR project consists of the basic elements shown in table 1.
In-water work would include the construction of two new spans across
the Columbia River (northbound and southbound) and six new spans across
the North Portland Harbor (one for light rail, one for local
[[Page 40496]]
traffic and pedestrians, and four for I-5 vehicle traffic), and the
demolition of the existing bridge spans. Demolition would occur after
the new spans are operational. Land-based work would consist of six
redesigned interchanges (at Hayden Island, Marine Drive, SR-14, and
three locations north of SR-14). Of these components, only the in-water
work on the new and existing bridge spans would have the potential to
impact marine mammals.
Land-based work related to the IBR project includes roadway
improvements, light rail track work, and construction staging sites.
Roadway improvements include updates to seven interchanges along a 5-mi
(8-km) segment of I-5 between Victory Boulevard in Portland and SR 500
in Vancouver. These improvements also include some reconfiguration of
adjacent local streets to complement the new interchange designs, as
well as new facilities for bicyclists and pedestrians. Temporary
earthwork, drainage, surfacing, and paving activities would be
required, utilities may need to be relocated, drainage appurtenances
put in place, and access to and from the freeway rerouted to
accommodate the new roadway or interchange. Permanent work would
proceed once traffic has been relocated to temporary facilities, if
necessary.
Construction of the various components of the light rail system
generally would include mobilization and site reparation; grading and
excavation; installation of underground utilities and signal tie-ins;
construction of systems foundations; installation of overhead
catenaries; concrete surface work; and finish work and landscaping.
This work would also require construction of an overhead catenary
system over the guideway to provide electrical power to the trains.
Staging of construction materials and equipment arriving by truck
or rail would be either within the limits of the project site or in
approved off-site locations. IBRP anticipates that larger construction
materials will arrive at the site by barge (addressed in in-water work,
below). Materials and equipment delivered by barge may be offloaded to
upland staging areas or may be temporarily staged on barges. Two
potential major staging areas have been identified and are shown on
figure 1-2 of the IBRP's application. The first site is the vacant 5.6-
acre (0.023 km\2\) former Thunderbird Hotel site on Hayden Island. The
second is a former rest-area site east of I-5 north of McLoughlin
Boulevard that is currently used as auxiliary parking for the Clark
College Athletic Annex. Following construction, the staging sites could
be converted for other uses. Key considerations for staging sites
include: (1) size and capacity to provide for heavy machinery and
material storage; (2) waterfront access for barges (either a slip or a
dock capable of handling heavy equipment and material); and (3) roadway
or rail access for landside transportation of materials by truck or
train.
Further detail on land-based project elements is available in the
IBRP's LOA application. These project elements would occur on land and
would not have the potential to impact marine mammals; thus they are
not discussed further in this notice.
In-water work would occur during the construction and demolition of
new and existing bridge spans. While the final design and configuration
of the new bridge spans is not yet available, three configurations for
the new Columbia River bridge spans are under consideration: double-
deck truss bridges with fixed spans, single-level bridges with fixed
spans, and single-level bridges with movable spans over the primary
navigation channel. The fixed-span bridges would provide up to 116 ft
(35.4 m) of vertical navigation clearance, and the movable spans would
provide at least 178 ft (54.3 m) of vertical navigation clearance
depending on the movable-span type (such as lift or double leaf
bascule). Since the project design is not finalized, the descriptions
of construction means and methods are intended to be inclusive of all
of the proposed design options. Where specific quantities or impacts
differ between the various design options, the description reflects the
design option with the greatest impact, or the largest quantities.
Temporary Work Structures
The proposed action would require the installation of several
temporary in-water and overwater structures, both during new bridge
construction and existing bridge demolition, to facilitate equipment
access, materials delivery and debris removal. These structures would
likely include a variety of temporary work platforms, bridges and
piers, temporary isolation/confinement systems, barges, and temporary
piles associated with these structures. Temporary work structures would
be designed by the contractor after a contract is awarded, but prior to
construction. For this reason, the exact size, quantity, type, and
configuration of temporary work structures are unknown. The proposed
action is designed based on reasonable assumptions, and typical
construction practices, and is intended to represent a reasonable and
realistic scenario.
Columbia River Bridge Spans
Construction of the Columbia River and North Portland Harbor
bridges would require a combination of temporary work bridges,
platforms, and piers (see figures 1-3 and 1-4 of the IBRP's LOA
application for further details). For purposes of this discussion, work
bridges are structures that have a point of connection with, and that
can be accessed from, the adjacent land, whereas work platforms and
piers are stand-alone structures that are accessed via barges.
Temporary work bridges, platforms, and piers would be supported by a
combination of 24-in (0.61 m) and 48-in (1.2 m) diameter hollow, steel
pipe piles. All temporary structures would be fully removed prior to
project completion. Bridge decking would be removed using appropriate
containment measures, and temporary piles would be removed with a
vibratory hammer or via direct pulling.
Table 2 shows the estimated number of temporary structures and
pilings anticipated for the 9 in-water construction seasons; table 3
shows the temporary structures and pilings anticipated for the first 5
years which would be covered under these proposed regulations. Work is
anticipated to begin first on the Columbia River bridge spans. In
total, IBRP estimates that the temporary work bridges, platforms, and
piers for construction of the Columbia River bridge would require up to
764, 24-in diameter piles, and approximately 447, 48-in diameter piles.
These structures would temporarily displace approximately 8,017 square
feet (sq ft) (744.8 square meters (m\2\)) of benthic habitat and would
temporarily shade approximately 184,187 sq ft (17,111.5 m\2\) of water
surface within the Columbia River. However, not all of these temporary
structures would be in place at the same time, as construction would
progress in a sequenced fashion and temporary work structures would be
removed prior to project completion. IBRP estimates that a given
temporary bridge, platform, or pier could be in place for up to
approximately 500 days each.
A temporary suspended shaft cap isolation system would be
constructed on top of permanent drilled shafts to avoid the need for
cofferdams and permanent concrete seals on the bottom of the riverbed.
The suspended shaft cap isolation system would be in place at each of
the four piers (three through six) for up to approximately 120 days.
This system would not involve temporary piles and is therefore not
discussed further in this analysis.
[[Page 40497]]
Table 2--Temporary In-Water and Overwater Components for Columbia and
North Portland Harbor Bridge Spans for the 9 Years of the IBR Project
------------------------------------------------------------------------
Approximate quantity
Temporary in-water and -------------------------------------------
overwater work elements North Portland
Columbia River Harbor
------------------------------------------------------------------------
Work Platforms/Bridges/Piers 2 work bridges; 4 8 work bridges; 912
and Associated Piles. work platforms; 2 (24-inch) piles;
piers; 764 (24- 208 (48-inch)
inch) piles; 447 piles.
(48-inch) piles.
Other Temporary Piles....... 100 (24-inch) piles. 100 (24-inch) piles.
Suspended Shaft Cap 4...................
Isolation System.
Sheet Pile Cofferdams 2...................
(Construction).
Sheet Pile Cofferdams 9...................
(Demolition).
Drilled Shaft Isolation .................... 52.
Casings.
Barges and Barge Mooring 12 barges; 160 (24- 6 barges; 216 (24-
Piles (Construction). inch) mooring piles. inch) mooring
piles.
Barges and Barge Mooring 6 barges; 304 (24- 6 barges; 100 (24-
Piles (Demolition). inch) mooring piles. inch) mooring
piles.
-------------------------------------------
Total................... 1,328 (24-inch) 447 1,328 (24-inch) 208
(48-inch). (48-inch).
------------------------------------------------------------------------
Table 3--Temporary Piles Anticipated for the First 5 Years of the IBR Project
----------------------------------------------------------------------------------------------------------------
Approximate quantities
-------------------------------------------------------------------------
Project elements Steel sheet
Number of structures 24-inch piles 48-inch piles piles (lineal
ft)
----------------------------------------------------------------------------------------------------------------
Work Platforms/Bridges/Piers and 4 work bridges; 4 work 840 460 ..............
Associated Piles. platforms; 2 piers;.
Other Temporary Piles................. N/A..................... 100 .............. ..............
Sheet Pile Cofferdams (Construction).. 2 cofferdams............ .............. .............. 1,500
Barges and Barge Mooring Piles 12 barges............... 160 .............. ..............
(Construction).
-------------------------------------------------------------------------
Total Temporary................... ........................ 1,100 460 1,500
----------------------------------------------------------------------------------------------------------------
In the Columbia River, temporary piles would also be installed as
part of sheet pile cofferdams, barge moorings, and other temporary
supports. Sheet pile cofferdams would be used to isolate certain in-
water work areas from active flow during construction. It is assumed
that two cofferdams would be required for the construction of nearshore
piers two and seven in the Columbia River. The shallow water depth at
these piers renders other methodologies less feasible. Sheet pile
cofferdams may also be required during demolition of the nine existing
bridge piers, but demolition is not anticipated to occur during the
first five construction seasons.
The two cofferdams used would be constructed of steel sheet piles
and would temporarily affect a combined area of approximately 25,095 sq
ft (2,331 m\2\) of benthic habitat. Piles would be installed and
removed with a vibratory hammer, which would be operated from temporary
work bridges or barges. Installation is expected to take approximately
10 to 15 days. Once sheet piles are installed, a permanent concrete
seal would be installed at the base of each cofferdam, and they would
be dewatered. Once construction of the pier is complete, sheet piles
would be removed with a vibratory hammer, but the concrete seals would
remain. Each cofferdam would be in place for a maximum of 500 calendar
days. It is anticipated that these cofferdams would not be installed at
the same time. However, the specific sequencing of installation and
removal will be dependent upon contractor means and methods, and other
scheduling factors.
Piles would also be installed to support stationary barges that
would be used as platforms to conduct work activities within the
Columbia River. Although multiple barges would be in use over the
course of construction, there would likely be a maximum of up to 12
stationary barges operating in the Columbia River at one time. Because
of wind, current, and wave action, temporary mooring piles will likely
be installed for some of these barges to anchor in place. For purposes
of this analysis, IBRP estimates that up to 160 temporary mooring piles
(18- to 24-in diameter steel pipe piles) would be installed within the
Columbia River, and that a given barge will be present in a given
location for up to approximately 120 days each, on average.
Additional temporary piles would likely be necessary throughout
construction for a variety of purposes, including supporting falsework
and formwork, pile templates, reaction piles, and other non-load-
bearing purposes. These piles would be 24-in diameter, open-ended steel
pipes and would be installed and removed solely with a vibratory pile
driver. These temporary piles would be fully removed prior to project
completion. IBRP estimates that approximately 100 such piles may be
required over the duration of construction in the Columbia River. These
piles will temporarily displace approximately 628 sq ft (58.3 m\2\) of
benthic habitat and will be in place for up to approximately 150 days
each.
North Portland Harbor Bridge Spans
If the final project sequencing changes, it is possible that work
could begin with the North Portland Harbor bridges. In total, IBRP
estimates that approximately 912, 24-in diameter piles, and
approximately 208, 48-in diameter piles would be required for the
temporary work bridges in North Portland Harbor. These structures would
temporarily displace approximately 5,479 sq ft (509 m\2\) of benthic
habitat, and temporarily shade approximately 208,000 sq ft (19,323
m\2\) of water surface within North Portland Harbor. Typically, only
two of these temporary work bridges would be in place at any one time,
though a
[[Page 40498]]
contractor could potentially install a greater number of work bridges.
No more than approximately 100,000 sq ft (9,290.3 m\2\) of temporary
work bridge would be installed at any given time. Each temporary bridge
in North Portland Harbor could be in place for up to approximately 850
days each.
In the North Portland Harbor, temporary piles would also be
installed to support barge moorings and other temporary supports. In
addition, temporary 19-ft diameter hollow steel casings will be
installed to isolate in-water work areas in which the permanent drilled
shafts for the bridge foundations can be constructed. These casings are
required in North Portland Harbor only due to the specific design
requirements of these drilled shafts and the way they attach to the
columns.
Construction within North Portland Harbor would most likely occur
from temporary work bridges, and barges are not expected to be used
extensively during construction or demolition within North Portland
Harbor. However, a contractor may elect to use barges, and barges would
also likely be used for delivery of materials. It is anticipated that
up to six barges may be present at a given time within North Portland
Harbor during construction and demolition. Construction barges may
require up to 216 temporary mooring piles (18- to 24-in diameter steel
pipe piles), and barges used during demolition may require up to 100
such temporary mooring piles. These barges would be in place for up to
approximately 50 days each.
Construction in the North Portland Harbor may also require
additional temporary piles as described for the Columbia River. These
piles would be 24-in diameter, open-ended steel pipes and would be
installed and removed solely with a vibratory pile driver. These
temporary piles would be fully removed prior to project completion.
IBRP estimates that approximately 100 such piles may be required over
the duration of construction in the North Portland Harbor. These piles
will temporarily displace approximately 628 sq ft (58.3 m\2\) of
benthic habitat and will be in place for up to approximately 150 days
each.
Permanent Bridge Structures
As described previously, the first five years of construction would
likely include construction of the Columbia River Bridge spans.
However, if construction schedules shift, it is possible that work
could begin in the North Portland Harbor as well. Thus, both project
components are described below.
Columbia River Bridge Spans
The proposed replacement bridges over the Columbia River would
consist of a steel or concrete superstructure constructed on top of a
series of pier complexes, supported on foundations consisting of 10-
foot-diameter drilled shafts with concrete shaft caps. Six of these
pier complexes would be located below the Ordinary High-Water Mark
(OHWM) of the Columbia River. In the double-decked bridge configuration
that is proposed under IBRP's ``Modified Locally Preferred
Alternative'' (LPA), each pier set would require approximately 12
drilled shafts with a single shaft cap measuring approximately 50 by
170 ft (15 by 52 m) at the water line.
The single-level bridge configurations would require the same
number of piers as the Modified LPA (six in-water piers per bridge and
two upland piers per bridge); however, each pier would require more
drilled shafts (16 drilled shafts per in-water pier, and 96 total in-
water drilled shafts), and longer shaft caps (approximately 230 ft (70
m) in length) compared to the Modified LPA configuration.
The single-level bridges with movable-span configuration would
require the largest foundations of the three options. The foundations
for piers two, three, four, and seven would be the same as the single-
level fixed-span configuration. The foundations for piers 5 and 6,
which would support the towers for the lift span, would require 22
drilled shafts each, and a continuous shaft cap measuring approximately
50 by 312 ft (15 by 95 m) at the water line.
Accounting for all potential design options under consideration,
IBRP's proposed action may require up to 108 drilled shafts to support
the in-water foundations for the Columbia River bridges (table 4) to
accommodate the single-level bridge with a movable-span-design option.
The foundations for nearshore piers two and seven would be constructed
within dewatered sheet pile cofferdams. The concrete seals that would
be placed to allow the cofferdam to be dewatered and isolated would
remain when the cofferdams are removed, and represent a permanent
benthic impact. In total, the foundations for the Columbia River
bridges would permanently displace approximately 33,577 sq ft (3,119
m\2\) of benthic habitat. Approximately 13,804 sq ft (1,282 m\2\) of
this permanent impact will occur in shallow water habitat (less than 20
ft (6.1 m) deep). All other pier foundations associated with the
Columbia River bridges would be located in deep-water areas.
Table 4--Permanent In-Water and Overwater Components for the Columbia River Bridge Spans for the 9 Years of the
IBR Project
----------------------------------------------------------------------------------------------------------------
Permanent in-water and Benthic impact
Existing/ proposed over-water work elements Approximate quantity (sf)
----------------------------------------------------------------------------------------------------------------
Proposed Bridges....................... Drilled Shafts (10-foot 108...................... 8,482
diameter) \a\.
Cofferdam Concrete Seals 2........................ 25,095
\a\.
Shaft Caps \a\............ 6........................ 0
Replacement Bridges 2 spans.................. 0
Overwater Deck (total)
\b\.
Existing Bridges (To be removed)....... Existing Bridge 9 foundations; 2,664 -33,289
Foundations. timber piles.
Existing Bridge Deck 2 existing spans......... 0
(total).
------------------------------------------------------------------------
Net Change......................... .......................... ......................... +288
----------------------------------------------------------------------------------------------------------------
\a\ Single-level bridge with movable-span configuration.
\b\ Single-level bridge with two-auxiliary-lane design option.
Key: sf = square feet.
The specific means and methods of construction, including
sequencing, will be developed by the contractors that are awarded the
contract for construction. A contractor may sequence the construction
in a way that may not
[[Page 40499]]
conform exactly to the conceptual sequence. However, all work will be
conducted consistent with the avoidance and minimization measures
described in section 11 of IBRP's application, and consistent with the
permits that are ultimately issued for IBRP's proposed action.
Depending upon which pier is being constructed, in-water and over-
water construction will likely occur according to the following general
sequence.
Mobilization, staging, and installation of Best Management
Practices (BMPs).
Install and dewater temporary cofferdam (piers two and
seven only).
Install temporary piles for barge mooring.
Install temporary work bridges, platforms, and/or piers
(including associated piles).
Install drilled shafts for each pier.
Install shaft cap isolation system (piers three through
six only)
Install shaft caps at the water level.
Remove cofferdam (piers two and seven only), or shaft cap
isolation system (piers three through six).
Construct columns on the shaft caps.
Construct bridge superstructure.
Connect superstructure spans with mid-span closures.
Remove all temporary work platforms, bridges, piers and
associated piles.
One or more of the activities identified above may be occurring at
more than one pier complex at a time, as the construction sequence
progresses.
The piers supporting the Columbia River bridge would be supported
on foundations of 10-foot (3.33-m) diameter drilled shafts.
Construction of these drilled shaft foundations requires installing a
permanent 10-foot diameter steel casing to a specified depth to the top
of the competent geological layer known as the Troutdale Formation. The
top layer of river substrate is composed of loose to very dense
alluvium (primarily sand and some fines), beneath which is
approximately 20 ft (6.1 m) of dense gravel, underlain by the Troutdale
Formation.
Installation of drilled shafts would be conducted by first placing
steel casing on the bottom of the river channel with a crane. The top
of the casing would be above the waterline to provide containment
during construction. The drilled shaft casing would be installed with
an oscillator which would be operated from a work bridge or platform.
As the shaft casing is being advanced, sand and substrate would be
removed from inside the casing using an auger and clamshell. Drilled
shaft casings would be advanced through primarily sandy substrates, and
not socketed into solid rock. If occasional obstructions such as large
boulders are encountered, these may be broken up with a drop chisel or
similar equipment, but no activities that would constitute down-the-
hole (DTH) drilling would be conducted. Equipment may be operated from
a work bridge or platform, or may also be operated from a barge.
Excavated soils would be temporarily placed onto a barge with
appropriate containment, and ultimately taken to an approved upland
site for disposal. No contaminated sediments have been documented at
the project site, but if contaminated sediments are encountered, they
would be managed and disposed of at a facility permitted for handling
such materials.
Once the interior of a given drilled shaft casing has been
excavated to the design depth (design depth would depend on design and
would vary for each shaft), a steel reinforcement cage would be
installed within the casing, and the shaft would be filled with
concrete. Concrete would most likely be transported to the site via
trucks, and pump trucks would be operated from the decks of temporary
bridges, platforms, or from barges. Concrete would be installed via a
tremie method. The interior of the casing would either be dewatered
prior to concrete installation, or the rising water would be collected
off the surface of the concrete as the pour elevation increases. Water
collected in this manner would be pumped into tanks, treated to meet
state water quality standards, and disposed of at an approved location.
Water levels within the temporary casing would be maintained at a lower
elevation than the surrounding river surface elevation to maintain
negative pressure. Once the concrete is installed, it would be left to
cure. Once cured, the casing would be permanent and left in place to
support the shaft cap isolation system.
Once the drilled shafts are installed, a concrete shaft cap would
be constructed atop the shafts at the waterline, and the concrete pier
and superstructure would be installed atop the pile cap. The means and
methods for the construction of the shaft caps would vary depending
upon the pier being constructed.
Construction of the shaft caps for piers two and seven would occur
within dewatered work areas within sheet pile cofferdams described
above. Construction of these shaft caps would occur primarily from the
temporary work bridges but would likely be supported by one or more
work barges and material barges. Construction of the shaft caps for
piers three through six would occur within a suspended shaft cap
isolation system, as described previously. Construction of these shaft
caps would occur primarily from temporary work platforms and would
likely be supported by one or more work barges and material barges.
Once the foundations and shaft caps have been installed, the
superstructure of the bridge will be constructed and installed. The
superstructure will consist of both precast and cast-in-place concrete
segments. Additional finish work will also be conducted, including
surfacing, paving, and installation of other finish features, such as
striping and signage.
Work on the superstructure may be conducted from the bridge deck,
from the deck of temporary work platforms and bridges, and/or from
barges. Construction of the superstructure would require cranes, work
barges, and material barges in the river year-round. Construction of
the superstructure, including cast-in-place concrete work, would occur
either above the OHWM elevation or within isolated work areas below the
OHWM (within sealed forms, cofferdams, or drilled shaft casings);
therefore, this work would be fully isolated from the river.
North Portland Harbor Bridge Spans
As with the Columbia River bridges, the general sequence of
construction of the North Portland Harbor bridges is expected to
proceed in a manner comparable to that which was developed for the CRC
project (75 FR78228, December 15, 2010). However, the specific means
and methods of construction, including sequencing, would be developed
by the contractors that are awarded the contract for construction. At
each pier, construction would likely occur according to the following
general sequence.
Mobilization, staging, and installation of BMPs.
Conduct debris removal as necessary to install temporary
piles, isolation casings, or drilled shafts.
Install temporary piles for barge mooring.
Install temporary work bridges and associated piles.
Install and dewater temporary isolation casing.
Install drilled shaft.
Construct columns on the drilled shafts.
Remove temporary isolation casing.
Construct a cap or crossbeam on top of the columns at pier
location.
Erect bridge girders on the caps or crossbeams.
[[Page 40500]]
Place the bridge deck on the girders.
Remove all temporary work bridges, isolation casings, and
barge mooring piles.
One or more of the activities identified above may be occurring at
more than one pier at a time, as the construction sequence progresses.
Table 5--Permanent In-Water and Overwater Components for the North Portland Harbor Bridge Spans for the 9 Years
of the IBR Project
----------------------------------------------------------------------------------------------------------------
Permanent in-water and Benthic impact
Existing/ proposed over-water work elements Approximate quantity (sf)
----------------------------------------------------------------------------------------------------------------
Proposed Bridges....................... Drilled Shafts (10-foot 52....................... 4,804
diameter).
Isolation Casing Seal (19- 52....................... 10,659
ft diameter).
Shaft Caps................ 0........................ 0
Replacement Bridges 6 Structures............. 0
Overwater Deck (total).
Existing Bridges (To be removed)....... Existing Bridge 18....................... -12,204
Foundations.
Existing Bridge Deck 1 Existing Structure..... 0
(total).
------------------------------------------------------------------------
Net Change......................... .......................... ......................... 2,539
----------------------------------------------------------------------------------------------------------------
Key: sf = square feet.
Table 5 shows the permanent elements to be installed over the
duration of the IBR project in the North Portland Harbor. Installation
of drilled shafts for the North Portland Harbor bridges would be
conducted in a manner similar to that described for the Columbia River
bridges, with two exceptions. In North Portland Harbor, drilled shafts
would be installed within a temporary drilled shaft isolation casing
approximately 19-ft (6.33-m) in diameter. Temporary isolation casings
would be placed on the river bottom and then either pushed into the
substrate approximately 5 to 10 ft (1.5 to 3 m) with weighted
equipment, or with a vibratory hammer. Once installed, a permanent
concrete seal would be cast-in-place at the base, which would allow
them to be dewatered. The top of the seal would be established at a
depth 3 ft (1 m) below the mudline.
Once a given temporary isolation casing has been installed, sealed,
and dewatered, a single 10-ft diameter permanent drilled shaft casing
would then be installed with an oscillator through the concrete seal.
Once the permanent casing has been installed to design depth, steel
reinforcement would be installed within the casing, and the shaft would
be filled with concrete in a manner similar to that described for the
Columbia River bridges. Once this process is complete, the temporary
isolation casing would be removed, but the permanent concrete seal
would remain.
The other difference in the construction of the foundations for the
North Portland Harbor bridges is that no shaft caps would be
constructed on the piers for the North Portland Harbor bridges. Once a
given drilled shaft has been completed and structurally approved, cast-
in-place columns would be installed directly on top of each drilled
shaft.
Pile Installation Methods
Table 6 shows estimated number of piles, duration, and installation
methods for the first 5 years of the IBR project. Installation of
temporary pipe and sheet piles would be conducted with a vibratory
hammer to the extent practicable. Removal of temporary piles may be via
direct pull or vibratory hammer. Vibratory pile driving and removal
activities are proposed to occur year-round with the possibility of up
to two hammers operating simultaneously. Because temporary piles would
be installed and removed throughout the duration of construction, IBRP
estimates that vibratory installation and extraction of 24- and 48-in
pipe piles could be conducted on up to approximately 250 days in each
year, which translates to approximately 1,250 days during the initial
5-year period that would be covered under the proposed Incidental Take
Regulations, and approximately 2,250 (nonconsecutive) days over the
course of the anticipated 9-years of in-water construction.
Piles for non-load-bearing structures (e.g. falsework, battered
piles, pile templates, barge mooring piles) would be installed and
removed solely with a vibratory hammer. These piles would be vibrated
into the sediment until refusal or specified elevation. Load-bearing
temporary piles (such as those that would be used on the temporary work
bridges and platforms) would also be installed to the extent
practicable with a vibratory hammer before being finished and/or
proofed, as necessary, with an impact hammer. Up to two vibratory pile-
driving rigs could be in operation on a given day. The contractor may
elect to have both a vibratory and impact pile-driving rig in operation
simultaneously. At this rate of production, with two vibratory pile-
driving rigs in operation, it is anticipated that up to approximately
20 temporary, hollow steel pipe piles could be installed and/or removed
on a given day. However, on an average day, there would likely be fewer
piles driven.
Steel sheet piles for temporary cofferdams would be installed and
removed solely with a vibratory hammer. Sheet piles for cofferdams
would generally be vibrated approximately 50 ft (15.2 m) into the
sediment. With two vibratory pile-driving rigs in operation, it is
anticipated that up to approximately 50 linear ft (15.2 m) of sheet
pile (or approximately twenty-five 2 ft-wide (0.6 m) sheet pile
sections) could be installed and/or removed on a given day. IBRP
estimates that vibratory installation or removal of sheet piles could
be conducted on up to approximately 200 (nonconsecutive) days.
Temporary drilled shaft isolation casings would be placed on the
river bottom with a crane, and then either pushed into the substrate
approximately 5 to 10 ft (1.5 to 3 m) deep with weighted equipment or
vibrated to this depth with a vibratory hammer. Installation and
removal of these temporary casings is estimated to take between 30 and
60 minutes per casing. At this rate of production, it is anticipated
that up to approximately four casings could be installed and/or removed
on a given day. For purposes of this consultation, it is conservatively
estimated that installation or removal of
[[Page 40501]]
these temporary isolation casings could be conducted on up to
approximately 50 (nonconsecutive) days.
An impact pile driver would be required to complete the
installation of load-bearing temporary piles and, and/or to proof these
piles to verify load-bearing capacity. Impact pile driving would be
limited to the in-water work window between September 15 and April 15
of each year. During construction up to two impact pile drivers may
operate simultaneously in close proximity to one another. IBRP
estimates that some amount of impact pile driving in the Columbia River
or North Portland Harbor would occur on approximately 445 days during
the initial 5-year period, and on approximately 735 days over the
course of the approximately nine seasons of in-water work to construct
the new bridges and demolish the existing bridges.
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TP19AU25.001
BILLING CODE 3510-22-C
An impact pile driver would be required to complete the
installation of load-bearing temporary piles and, and/or to proof these
piles to verify load-bearing capacity. IBRP estimates that a total of
approximately 3,311 temporary piles would be installed and removed
during the 9-year construction of the Columbia River and North Portland
Harbor bridges. These piles would be staged throughout the in-water
construction and demolition periods, and it is assumed that between 100
and 400 temporary piles may be in the water at any given time. An
average of six temporary, load-bearing piles could be installed per day
using up to two impact drivers at the same time.
Rotary Drilling for Shafts
The 10-foot-diameter, hollow steel casings for the permanent
drilled shafts would be installed with an oscillator, which would be
operated from a temporary work bridge or platform. A total of 160 such
casings would be required (108 for the Columbia River bridge, and 52
for the North Portland Harbor bridges). The amount of time that an
oscillator would be operated to install a given permanent shaft casing
would vary depending on the design depth of each shaft, its location,
and other factors. IBRP estimates that it would take up to 5 days to
completely install a typical 10-ft diameter casing. Some casings may be
able to be installed more quickly, and others may proceed more slowly.
Oscillation of permanent drilled shaft casings could be conducted on up
to approximately 800 (nonconsecutive) days. Rotary drilling is not
expected to produce sound that is likely to result in incidental take
of marine mammals due to the relatively
[[Page 40502]]
low source levels, position of the sound source in the sediment layers
and associated higher transmission loss, and the industrial nature of
the project location. Drilling is not addressed further in this
proposed rule.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' stock assessment reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 7 lists all species or stocks for which take is expected and
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality (M/
SI) from anthropogenic sources are included here as gross indicators of
the status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Pacific and Alaska SARs. All values presented in table 7 are
the most recent available at the time of publication, including from
the draft 2024 SARs, and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
Table 7--Species With Estimated Take From the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance Nbest,
ESA/ MMPA status; (CV, Nmin, most recent Annual M/
Common name Scientific name MMPA stock strategic (Y/N) abundance survey) \2\ PBR SI \3\
\1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and sea lions):
California sea lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >321
2014).
Steller sea lion................ Eumetopias jubatus..... Eastern................ -, -, N 36,308 (N/A, 36,308, 2,178 93.2
2022).\4\
Family Phocidae (earless seals):
Harbor seal......................... Phoca vitulina......... OR/WA Coastal.......... -, -, N 22,549 (UND, 19,561, \6\UND 10.6
2022).\5\
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: endangered (E), threatened (T)/MMPA status: depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal SARs online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. CV is
coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N/A).
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the United
States only.
\5\ Most recent SAR does not include an abundance estimate for this stock. These data are for the Washington coast and thus underestimate the size of
the OR/WA Coastal stock; estimates are from Pearson et al. 2024.
\6\ UND means undetermined.
As indicated above, all 3 species in table 7 temporally and
spatially co-occur with the activity to the degree that take is
reasonably likely to occur. In addition to what is included in sections
3 and 4 of the IBRP's application (https://www.fisheries.noaa.gov/action/incidental-take-authorization-interstate-bridge-replacement-programs-interstate-bridge), the SARs (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and
NMFS' website, we provide further detail below informing the baseline
for species likely to be found in the project area (e.g., information
regarding current UMEs and known important habitat areas, such as
biologically important areas (BIAs; https://oceannoise.noaa.gov/biologically-important-areas) (Calambokidis et al., 2024)).
California Sea Lion
California sea lions are the most frequently sighted sea lion found
in Washington coastal waters and use haulout sites along the outer
coast, the Strait of Juan de Fuca, and in the Puget Sound. California
sea lions have been observed in increasing numbers farther up the
Columbia River since the 1980s, first to the Astoria area, and then to
the Cowlitz River and Bonneville Dam (WDFW, 2020). However, the number
of California sea lions observed at Bonneville Dam has been in decline,
ranging from 149 individuals in 2016 to 24 individuals in 2021,
including no observations of California sea lions during fall and
winter of 2019 to 2020 (van der Leeuw and Tidwell, 2022). No California
sea lions were observed at Bonneville Dam during fall 2023 monitoring
efforts between July 25 and December 31. During spring 2024, this
species was sighted beginning on March 2 and were last seen on May 31.
Peak California sea lion abundance at the dam was 40 individuals on
March 13, 2024; average abundance was approximately 4 individuals
during this counting period (Clark et al., 2024).
[[Page 40503]]
Steller Sea Lion
Steller sea lions that occur in the Lower Columbia River, including
the project vicinity, are members of the eastern distinct population
segment (DPS), ranging from Southeast Alaska to central California,
including Washington (Jeffries et al., 2000; Scordino, 2006; NMFS,
2013). In Washington, Steller sea lions occur mainly along the outer
coast from the Columbia River to Cape Flattery (Jeffries et al., 2000).
Smaller numbers use the Strait of Juan de Fuca, San Juan Islands, and
Puget Sound south to about the Nisqually River mouth in Thurston and
Pierce counties (Wiles, 2015). The eastern DPS of Steller sea lions has
historically bred on rookeries located in Southeast Alaska, British
Columbia, Oregon, and California. However, within the last several
years, a new rookery has become established on the outer Washington
coast at the Carroll Island and Sea Lion Rock complex (Muto et al.,
2019).
Similar to California sea lions, Steller sea lions have also been
observed at the base of Bonneville Dam in recent years, feeding on
white sturgeon (Acipenser transmontanus) and salmonids (WDFW, 2020).
However, Steller sea lions were not observed entering the Columbia
River in significant numbers until the 1980s and they were not observed
at the dam until after 2003. In 2023, Steller sea lions were observed
beginning on July 25 and were seen through December 31; average
abundance was approximately 5 sea lions per day, and the peak abundance
was 21 individuals on August 29, 2023. In the spring of 2024, Steller
sea lions were sighted from January 3 through May 21, with an average
abundance of approximately 7 individuals per day. Peak abundance for
this species during this count period was 38 animals on May 1, 2024
(Clark et al., 2024).
Harbor Seal
Harbor seals are the most common, widely distributed marine mammal
found in Washington marine waters and are frequently observed in the
nearshore marine environment. The Oregon/Washington Coastal Stock was
most recently estimated at 24,732 harbor seals in 1999. More recent
abundance data is not available and there is no current estimate of
abundance for this stock (Carretta et al., 2022). Harbor seals use
hundreds of sites to rest or haul out along coastal and inland waters,
including intertidal sand bars and mudflats in estuaries; intertidal
rocks and reefs; sandy, cobble, and rocky beaches; islands; and log
booms, docks, and floats in all marine areas of the state (Jeffries et
al., 2003).
Harbor seals in this population are typically non-migratory and
reside year-round in the Columbia River, and generally remain in the
same area throughout the year for breeding and feeding. Pupping seasons
in coastal estuaries vary geographically; in the Columbia River,
Willapa Bay, and Grays Harbor, pups are born from mid-April through
June (Jeffries et al., 2003). Harbor seals in the Columbia River do
exhibit some seasonal movement upriver, including into or through the
project area of ensonification, to follow winter and spring runs of
Pacific eulachon (Thaleichthys pacificus) and outmigrating juvenile
salmon (Oncorhynchus spp.), and they are observed regularly in portions
of the Columbia River including the action area. Within the lower
Columbia River, they tend to congregate to feed at the mouths of
tributary rivers, including the Cowlitz and Kalama rivers (River Miles
68 and 73, respectively). WDFW's atlas of seal and sea lion haulout
sites (Jeffries et al., 2000) identifies shoals near the confluence of
the Cowlitz and Columbia Rivers located approximately 38 mi (61 km)
upstream of the project site as a documented haulout for harbor seals.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Generalized hearing ranges were
chosen based on the approximately 65 decibel (dB) threshold from
composite audiograms, previous analyses in NMFS (2018), and/or data
from Southall et al. (2007) and Southall et al. (2019). We note that
the names of two hearing groups and the generalized hearing ranges of
all marine mammal hearing groups have been recently updated (NMFS 2024)
as reflected below in Table 8. Of the species potentially present in
the action area, California and Steller sea lions are otariid
pinnipeds, and harbor seals are phocid pinnipeds.
Table 8--Marine Mammal Hearing Groups (NMFS, 2024)
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very high-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al., 2007;
Southall et al., 2019. Additionally, animals are able to detect very
loud sounds above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken
[[Page 40504]]
by this activity. The Negligible Impact Analysis and Determination
section considers the content of this section, the Estimated Take of
Marine Mammals section, and the Proposed Mitigation section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and whether those
impacts are reasonably expected to, or reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.
Acoustic effects on marine mammals during the specified activity
are expected to potentially occur from impact and vibratory pile
installation and removal. The effects of underwater noise from IBRP's
proposed activities have the potential to result in Level B harassment
of marine mammals in the action area and, for some individuals as a
result of certain activities, Level A harassment.
The proposed activities would result in the construction of new
bridge spans across the Columbia River and North Portland Harbor. There
are a variety of types and degrees of effects to marine mammals, prey
species, and habitat that could occur as a result of the IBR project.
Below we provide a brief description of the types of sound sources that
would be generated by the project, the general impacts from these types
of activities, and an analysis of the anticipated impacts on marine
mammals from the project, with consideration of the proposed mitigation
measures.
The project location is within the Columbia River and North
Portland Harbor, adjacent to existing bridges, marinas, and vessel
transit channels. While there are limited existing data on the current
sound levels, the site is a high-use area with regular vessel traffic,
industrial waterfronts, and vehicle noise. Marine mammals passing
through the area would potentially be exposed to the existing
background conditions at any time, and to pile driving sounds when
construction activities are ongoing.
Description of Sound Sources for the Specified Activities
Activities associated with the project that have the potential to
incidentally take marine mammals though exposure to sound would include
attenuated and unattenuated impact pile driving, vibratory pile
installation, and vibratory pile extraction.
Impact hammers typically operate by repeatedly dropping and/or
pushing a heavy piston onto a pile to drive the pile into the
substrate. Sound generated by impact hammers is impulsive,
characterized by rapid rise times and high peak levels, a potentially
injurious combination (Hastings and Popper, 2005). Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the substrate. Vibratory hammers typically produce
less sound (i.e., lower levels) than impact hammers. Peak sound
pressure levels (SPLs) may be 180 dB or greater, but are generally 10
to 20 dB lower than SPLs generated during impact pile driving of the
same-sized pile (Oestman et al., 2009; California Department of
Transportation (CALTRANS), 2015, 2020). Sounds produced by vibratory
hammers are non-impulsive; compared to sounds produced by impact
hammers, the rise time is slower, reducing the probability and severity
of injury, and the sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
The likely or possible impacts of the IBRP's proposed activities on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of the equipment and personnel; however, given there are no
known pinniped haul-out sites in the vicinity of the project site,
visual and other non-acoustic stressors would be limited, and any
impacts to marine mammals are expected to primarily be acoustic in
nature.
Potential Effects of Underwater Sound on Marine Mammals
The introduction of anthropogenic noise into the aquatic
environment from impact and vibratory pile driving is the primary means
by which marine mammals may be harassed from the IBRP's specified
activity. Anthropogenic sounds cover a broad range of frequencies and
sound levels and can have a range of highly variable impacts on marine
life from none or minor to potentially severe responses depending on
received levels, duration of exposure, behavioral context, and various
other factors. Broadly, underwater sound from active acoustic sources,
such as those in the Project, can potentially result in one or more of
the following: temporary or permanent hearing impairment, non-auditory
physical or physiological effects, behavioral disturbance, stress, and
masking (Richardson et al., 1995; Gordon et al., 2003; Nowacek et al.,
2007; Southall et al., 2007; G[ouml]tz et al., 2009).
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly as we do not expect that
use of pile driving hammers (impact and vibratory) are reasonably
likely to result in such effects (see below for further discussion).
Potential effects from impulsive sound sources can range in severity
from effects such as behavioral disturbance or tactile perception to
physical discomfort, slight injury of the internal organs and the
auditory system, or mortality (Yelverton et al., 1973). Non-auditory
physiological effects or injuries that theoretically might occur in
marine mammals exposed to high level underwater sound or as a secondary
effect of extreme behavioral reactions (e.g., change in dive profile as
a result of an avoidance reaction) caused by exposure to sound include
neurological effects, bubble formation, resonance effects, and other
types of organ or tissue damage (Cox et al., 2006; Southall et al.,
2007; Zimmer and Tyack, 2007; Tal et al., 2015). The project activities
considered here do not involve the use of devices such as explosives or
mid-frequency tactical sonar that are associated with these types of
effects.
In general, animals exposed to natural or anthropogenic sound may
experience physical and psychological effects, ranging in magnitude
from none to severe (Southall et al., 2007, 2019). Exposure to
anthropogenic noise has the potential to result in auditory threshold
shifts and behavioral reactions (e.g., avoidance, temporary cessation
of foraging and vocalizing, changes in dive behavior). It can also lead
to non-observable physiological responses, such an increase in stress
hormones. Additional noise in a marine mammal's habitat can mask
acoustic cues used by marine mammals to carry out daily functions, such
as communication and predator and prey detection.
The degree of effect of an acoustic exposure on marine mammals is
dependent on several factors, including, but not limited to, sound type
(e.g., impulsive vs. non-impulsive), signal characteristics, the
species, age and sex class (e.g., adult male vs. mom with calf),
duration of exposure, the distance between the noise source and the
animal, received levels, behavioral state at time of exposure, and
previous history with exposure (Wartzok et al., 2004; Southall et al.,
2007). In general, sudden, high-intensity sounds can cause hearing loss
as can longer exposures to lower-intensity sounds. Moreover, any
temporary or permanent loss of hearing, if it occurs at all, will occur
almost exclusively for noise within an animal's hearing range. We
describe below the specific manifestations of acoustic effects that may
occur based on the activities proposed by IBRP.
[[Page 40505]]
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First (at the greatest distance) is the area within which the
acoustic signal would be audible (potentially perceived) to the animal
but not strong enough to elicit any overt behavioral or physiological
response. The next zone (closer to the receiving animal) corresponds
with the area where the signal is audible to the animal and of
sufficient intensity to elicit behavioral or physiological
responsiveness. The third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
Below, we provide additional detail regarding potential impacts on
marine mammals and their habitat from noise in general, starting with
hearing impairment, as well as from the specific activities IBRP plans
to conduct, to the degree it is available.
Hearing Threshold Shifts. NMFS defines a noise-induced threshold
shift (TS) as a change, usually an increase, in the threshold of
audibility at a specified frequency or portion of an individual's
hearing range above a previously established reference level (NMFS,
2018, 2024). The amount of threshold shift is customarily expressed in
dB. A TS can be permanent or temporary. As described in NMFS (2018,
2024) there are numerous factors to consider when examining the
consequence of TS, including, but not limited to, the signal temporal
pattern (e.g., impulsive or non-impulsive), likelihood an individual
would be exposed for a long enough duration or to a high enough level
to induce a TS, the magnitude of the TS, time to recovery (seconds to
minutes or hours to days), the frequency range of the exposure (i.e.,
spectral content), the hearing frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal; e.g., Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Auditory Injury (AUD INJ). NMFS (2024) defines AUD INJ as damage to
the inner ear that can result in destruction of tissue, such as the
loss of cochlear neuron synapses or auditory neuropathy (Houser 2021;
Finneran 2024). AUD INJ may or may not result in a permanent threshold
shift (PTS). PTS is subsequently defined as a permanent, irreversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2024). PTS does not generally affect more than a
limited frequency range, and an animal that has incurred PTS has some
level of hearing loss at the relevant frequencies; typically animals
with PTS or other AUD INJ are not functionally deaf (Au and Hastings,
2008; Finneran, 2016). Available data from humans and other terrestrial
mammals indicate that a 40-dB threshold shift approximates AUD INJ
onset (see Ward et al., 1958, 1959; Ward, 1960; Kryter et al., 1966;
Miller, 1974; Ahroon et al., 1996; Henderson et al., 2008). AUD INJ
levels for marine mammals are estimates, as with the exception of a
single study unintentionally inducing PTS in a harbor seal (Phoca
vitulina) (Kastak et al., 2008), there are no empirical data measuring
AUD INJ in marine mammals largely due to the fact that, for various
ethical reasons, experiments involving anthropogenic noise exposure at
levels inducing AUD INJ are not typically pursued or authorized (NMFS,
2024).
Temporary Threshold Shift (TTS). TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2024), and is not considered an AUD INJ. Based
on data from marine mammal TTS measurements (see Southall et al., 2007,
2019), a TTS of 6 dB is considered the minimum threshold shift clearly
larger than any day-to-day or session-to-session variation in a
subject's normal hearing ability (Finneran et al., 2000, 2002; Schlundt
et al., 2000). As described in Finneran (2015), marine mammal studies
have shown the amount of TTS increases with the 24-hour cumulative
sound exposure level (SEL24) in an accelerating fashion: at
low exposures with lower SEL24, the amount of TTS is
typically small and the growth curves have shallow slopes. At exposures
with higher SEL24, the growth curves become steeper and
approach linear relationships with the sound exposure level (SEL).
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to more impactful (similar to those discussed in
auditory masking, below). For example, a marine mammal may be able to
readily compensate for a brief, relatively small amount of TTS in a
non-critical frequency range that takes place during a time when the
animal is traveling through the open ocean, where ambient noise is
lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during time when communication is critical for successful mother/calf
interactions could have more severe impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS) (Finneran 2015). In many cases,
hearing sensitivity recovers rapidly after exposure to the sound ends.
For pinnipeds in water, measurements of TTS are limited to harbor
seals, elephant seals (Mirounga angustirostris), bearded seals
(Erignathus barbatus) and California sea lions (Kastak et al., 1999,
2007; Kastelein et al., 2019b, 2019c, 2021, 2022a, 2022b; Reichmuth et
al., 2019; Sills et al., 2020). TTS was not observed in spotted (Phoca
largha) and ringed (Pusa hispida) seals exposed to single airgun
impulse sounds at levels matching previous predictions of TTS onset
(Reichmuth et al., 2016). These studies examine hearing thresholds
measured in marine mammals before and after exposure to intense or
long-duration sound exposures. The difference between the pre-exposure
and post-exposure thresholds can be used to determine the amount of
threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds below the region of best sensitivity for a species or hearing
group are less hazardous than those near the region of best sensitivity
(Finneran and Schlundt, 2013). At low frequencies,
[[Page 40506]]
onset-TTS exposure levels are higher compared to those in the region of
best sensitivity (i.e., a low frequency noise would need to be louder
to cause TTS onset when TTS exposure level is higher), as shown for
harbor porpoises and harbor seals (Kastelein et al., 2019a, 2019c).
Note that in general, harbor seals and harbor porpoises have a lower
TTS onset than other measured pinniped or cetacean species (Finneran,
2015). In addition, TTS can accumulate across multiple exposures, but
the resulting TTS will be less than the TTS from a single, continuous
exposure with the same SEL (Mooney et al., 2009; Finneran et al., 2010;
Kastelein et al., 2014, 2015). This means that TTS predictions based on
the total, SEL24 will overestimate the amount of TTS from
intermittent exposures, such as sonars and impulsive sources.
Relationships between TTS and AUD INJ thresholds have not been
studied in marine mammals, and there are no measured PTS data for
cetaceans, but such relationships are assumed to be similar to those in
humans and other terrestrial mammals. AUD INJ typically occurs at
exposure levels at least several dB above that inducing mild TTS (e.g.,
a 40-dB threshold shift approximates AUD INJ onset (Kryter et al.,
1966; Miller, 1974), while a 6-dB threshold shift approximates TTS
onset (Southall et al., 2007, 2019). Based on data from terrestrial
mammals, a precautionary assumption is that the AUD INJ thresholds for
impulsive sounds (such as impact pile driving pulses as received close
to the source) are at least 6 dB higher than the TTS threshold on a
peak-pressure basis and AUD INJ cumulative sound exposure level
thresholds are 15 to 20 dB higher than TTS cumulative sound exposure
level thresholds (Southall et al., 2007, 2019). Given the higher level
of sound or longer exposure duration necessary to cause AUD INJ as
compared with TTS, it is considerably less likely that AUD INJ could
occur.
Behavioral Effects. Exposure to noise also has the potential to
behaviorally disturb marine mammals to a level that rises to the
definition of harassment under the MMPA. Generally speaking, NMFS
considers a behavioral disturbance that rises to the level of
harassment under the MMPA a non-minor response--in other words, not
every response qualifies as behavioral disturbance, and for responses
that do, those of a higher level, or accrued across a longer duration,
have the potential to affect foraging, reproduction, or survival.
Behavioral disturbance may include a variety of effects, including
subtle changes in behavior (e.g., minor or brief avoidance of an area
or changes in vocalizations), more conspicuous changes in similar
behavioral activities, and more sustained and/or potentially severe
reactions, such as displacement from or abandonment of high-quality
habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); and avoidance of areas where sound sources are located.
In addition, pinnipeds may increase their haul out time, possibly to
avoid in-water disturbance (Thorson and Reyff, 2006).
Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic
factors (e.g., species, state of maturity, experience, current
activity, reproductive state, auditory sensitivity, time of day), as
well as the interplay between factors (e.g., Richardson et al., 1995;
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007;
Archer et al., 2010). Behavioral reactions can vary not only among
individuals but also within an individual, depending on previous
experience with a sound source, context, and numerous other factors
(Ellison et al., 2012), and can vary depending on characteristics
associated with the sound source (e.g., whether it is moving or
stationary, number of sources, distance from the source). In general,
pinnipeds seem more tolerant of, or at least habituate more quickly to,
potentially disturbing underwater sound than do cetaceans, and
generally seem to be less responsive to exposure to industrial sound
than most cetaceans. Please see appendices B and C of Southall et al.
(2007) and Gomez et al. (2016) for reviews of studies involving marine
mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National Research Council (NRC), 2005).
Controlled experiments with captive marine mammals have shown
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources (e.g.,
seismic airguns) have been varied but often consist of avoidance
behavior or other behavioral changes (Richardson et al., 1995; Morton
and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal (e.g., Erbe et al., 2019). If a marine mammal does react
briefly to an underwater sound by changing its behavior or moving a
small distance, the impacts of the change are unlikely to be
significant to the individual, let alone the stock or population. If a
sound source displaces marine mammals from an important feeding or
breeding area for a prolonged period, impacts on individuals and
populations could be significant (e.g., Lusseau and Bejder, 2007;
Weilgart, 2007; NRC, 2005). However, there are broad categories of
potential response, which we describe in greater detail here, that
include alteration of dive behavior, alteration of foraging behavior,
effects to breathing, interference with or alteration of vocalization,
avoidance, and flight.
Avoidance and displacement--Changes in dive behavior can vary
widely and may consist of increased or decreased dive times and surface
intervals as well as changes in the rates of ascent and descent during
a dive (e.g., Frankel and Clark, 2000; Costa et al., 2003; Ng and
Leung, 2003; Nowacek et al., 2004; Goldbogen et al., 2013a, 2013b,
Blair et al., 2016). Variations in dive behavior may reflect
interruptions in biologically significant activities (e.g., foraging)
or they may be of little biological significance. The impact of an
alteration to dive behavior resulting from an acoustic exposure depends
on what the animal is doing at the time of the exposure and the type
and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic
[[Page 40507]]
sound exposure, so it is usually inferred by observed displacement from
known foraging areas, the appearance of secondary indicators (e.g.,
bubble nets or sediment plumes), or changes in dive behavior. Acoustic
and movement bio-logging tools also have been used in some cases to
infer responses to anthropogenic noise. For example, Blair et al.
(2015) reported significant effects on humpback whale (Megaptera
novaeangliae) foraging behavior in Stellwagen Bank in response to ship
noise including slower descent rates, and fewer side-rolling events per
dive with increasing ship nose. In addition, Wisniewska et al. (2018)
reported that tagged harbor porpoises demonstrated fewer prey capture
attempts when encountering occasional high-noise levels resulting from
vessel noise as well as more vigorous fluking, interrupted foraging,
and cessation of echolocation signals observed in response to some
high-noise vessel passes. As for other types of behavioral response,
the frequency, duration, and temporal pattern of signal presentation,
as well as differences in species sensitivity, are likely contributing
factors to differences in response in any given circumstance (e.g.,
Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko
et al., 2007). A determination of whether foraging disruptions incur
fitness consequences would require information on or estimates of the
energetic requirements of the affected individuals and the relationship
between prey availability, foraging effort and success, and the life
history stage of the animal.
Respiration rates vary naturally with different behaviors and
alterations to breathing rate as a function of acoustic exposure can be
expected to co-occur with other behavioral reactions, such as a flight
response or an alteration in diving. However, respiration rates in and
of themselves may be representative of annoyance or an acute stress
response. Various studies have shown that respiration rates may either
be unaffected or could increase, depending on the species and signal
characteristics, again highlighting the importance in understanding
species differences in the tolerance of underwater noise when
determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001; 2005; 2006; Gailey et
al., 2007). For example, harbor porpoise respiration rates increased in
response to pile driving sounds at and above a received broadband SPL
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike
(SELss): 127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
(Eschrictius robustus) are known to change direction--deflecting from
customary migratory paths--in order to avoid noise from seismic surveys
(Malme et al., 1984). Harbor porpoises, Atlantic white-sided dolphins
(Lagenorhynchus actusus), and minke whales have demonstrated avoidance
in response to vessels during line transect surveys (Palka and Hammond,
2001). In addition, beluga whales (Delphinapterus leucas) in the St.
Lawrence Estuary in Canada have been reported to increase levels of
avoidance with increased boat presence by way of increased dive
durations and swim speeds, decreased surfacing intervals, and by
bunching together into groups (Blane and Jaakson, 1994). Avoidance may
be short-term, with animals returning to the area once the noise has
ceased (e.g., Bowles et al., 1994; Goold, 1996; Stone et al., 2000;
Morton and Symonds, 2002; Gailey et al., 2007). Longer-term
displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann et
al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (England et al., 2001). However, it should be noted
that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Physiological stress responses. An animal's perception of a threat
may be sufficient to trigger stress responses consisting of some
combination of behavioral responses, autonomic nervous system
responses, neuroendocrine responses, or immune responses (e.g., Selye,
1950; Moberg, 2000). In many cases, an animal's first and sometimes
most economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a
[[Page 40508]]
significant long-term effect on an animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005; Ayres et al., 2012; Yang
et al., 2022). Stress responses due to exposure to anthropogenic sounds
or other stressors and their effects on marine mammals have also been
reviewed (Fair and Becker, 2000; Romano et al., 2002b) and, more
rarely, studied in wild populations (e.g., Romano et al., 2002a). For
example, Rolland et al. (2012) found that noise reduction from reduced
ship traffic in the Bay of Fundy was associated with decreased stress
in North Atlantic right whales. In addition, Lemos et al. (2022)
observed a correlation between higher levels of fecal glucocorticoid
metabolite concentrations (indicative of a stress response) and vessel
traffic in gray whales. Yang et al. (2022) studied behavioral and
physiological responses in captive bottlenose dolphins exposed to
playbacks of ``pile-driving-like'' impulsive sounds, finding
significant changes in cortisol and other physiological indicators but
only minor behavioral changes. These and other studies lead to a
reasonable expectation that some marine mammals will experience
physiological stress responses upon exposure to acoustic stressors and
that it is possible that some of these would be classified as
``distress.'' In addition, any animal experiencing TTS would likely
also experience stress responses (NRC, 2005), however distress is an
unlikely result of this project based on observations of marine mammals
during previous, similar construction projects.
Vocalizations and Auditory Masking. Since many marine mammals rely
on sound to find prey, moderate social interactions, and facilitate
mating (Tyack, 2008), noise from anthropogenic sound sources can
interfere with these functions, but only if the noise spectrum overlaps
with the hearing sensitivity of the receiving marine mammal (Southall
et al., 2007; Clark et al., 2009; Hatch et al., 2012). Chronic exposure
to excessive, though not high-intensity, noise could cause masking at
particular frequencies for marine mammals that utilize sound for vital
biological functions (Clark et al., 2009). Acoustic masking is when
other noises such as from human sources interfere with an animal's
ability to detect, recognize, or discriminate between acoustic signals
of interest (e.g., those used for intraspecific communication and
social interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environment
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. The ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions (Hotchkin and
Parks, 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales (Orcinus
orca) have been observed to increase the length of their songs (Miller
et al., 2000; Fristrup et al., 2003) or vocalizations (Foote et al.,
2004), respectively, while North Atlantic right whales (Eubalaena
glacialis) have been observed to shift the frequency content of their
calls upward while reducing the rate of calling in areas of increased
anthropogenic noise (Parks et al., 2007). Fin whales (Balaenoptera
physalus) have also been documented lowering the bandwidth, peak
frequency, and center frequency of their vocalizations under increased
levels of background noise from large vessels (Castellote et al. 2012).
Other alterations to communication signals have also been observed. For
example, gray whales, in response to playback experiments exposing them
to vessel noise, have been observed increasing their vocalization rate
and producing louder signals at times of increased outboard engine
noise (Dahlheim and Castellote, 2016). Alternatively, in some cases,
animals may cease sound production during production of aversive
signals (Bowles et al., 1994, Wisniewska et al., 2018).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other
[[Page 40509]]
costs as animals change their vocalization behavior (e.g., Miller et
al., 2000; Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark,
2010; Holt et al., 2009). Masking can be reduced in situations where
the signal and noise come from different directions (Richardson et al.,
1995), through amplitude modulation of the signal, or through other
compensatory behaviors, including modifications of the acoustic
properties of the signal or the signaling behavior (Hotchkin and Parks,
2013). Masking can be tested directly in captive species (e.g., Erbe,
2008), but in wild populations it must be either modeled or inferred
from evidence of masking compensation. There are few studies addressing
real-world masking sounds likely to be experienced by marine mammals in
the wild (e.g., Branstetter et al., 2013).
Masking occurs in the frequency band that the animals utilize, and
is more likely to occur in the presence of broadband, relatively
continuous noise sources such as vibratory pile driving. The energy
distribution of vibratory pile driving sound covers a broad frequency
spectrum, and is anticipated to be within the audible range of marine
mammals present in the proposed action area. Since noises generated
from the proposed construction activities are mostly concentrated at
low frequencies (<2 kHz), these activities likely have less effect on
mid-frequency sounds produced by marine mammals. However, lower
frequency noises are more likely to affect detection of communication
calls and other potentially important natural sounds such as surf and
prey noise. Low-frequency noise may also affect communication signals
when they occur near the frequency band for noise and thus reduce the
communication space of animals (e.g., Clark et al., 2009) and cause
increased stress levels (e.g., Holt et al., 2009). Unlike TS, masking,
which can occur over large temporal and spatial scales, can potentially
affect the species at population, community, or even ecosystem levels,
in addition to individual levels. Masking affects both senders and
receivers of the signals, and at higher levels for longer durations,
could have long-term chronic effects on marine mammal species and
populations. However, the noise generated by the IBRP's proposed
activities will only occur intermittently in a relatively small area
focused around the proposed construction site. While the project
duration is expected to be long-term, marine mammal presence at the
project site is transitory, as individuals move up and down the river
following migratory prey. Individuals are not known or expected to
spend more than a few days per year at the project site. Thus, while
the IBRP's proposed activities may mask some acoustic signals that are
relevant to the daily behavior of marine mammals, the short-term
duration and limited areas affected make it very unlikely that the
fitness of individual marine mammals would be impacted.
While in some cases marine mammals have exhibited little to no
obviously detectable response to certain common or routine
industrialized activities (Cornick et al., 2011; Horley and Larson,
2023), it is possible some animals may at times be exposed to received
levels of sound above the AUD INJ and Level B harassment thresholds
during the proposed project. This potential exposure in combination
with the nature of planned activity (e.g., vibratory pile driving,
impact pile driving) means it is possible that take by Level A and
Level B harassment could occur over the total estimated period of
activities; therefore, NMFS in response to the IBRP's IHA application
proposes to authorize take by Level A and Level B harassment from the
IBRP's proposed construction activities.
Airborne Acoustic Effects. Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with construction
activities that have the potential to cause behavioral harassment,
depending on their distance from these activities. Airborne noise would
primarily be an issue for pinnipeds that are swimming or hauled out
near the project site within the range of noise levels elevated above
airborne acoustic harassment criteria. Although pinnipeds are known to
haul-out regularly on man-made objects, we believe that incidents of
take resulting solely from airborne sound are unlikely due to the
proximity between the proposed project area and the known haulout sites
(e.g., Powerline Islands, approximately 13 mi (21 km) upriver).
We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled-
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to flush from haulouts,
temporarily abandon the area, and or move further from the source.
However, these animals would previously have been `taken' because of
exposure to underwater sound above the behavioral harassment
thresholds, which are in all cases larger than those associated with
airborne sound. Thus, the behavioral harassment of these animals is
already accounted for in these estimates of potential take.
Additionally, there are no known pinniped haulouts in the IBR project
vicinity, and all animals are expected to be in the water for the
duration of their passage and potential exposures. Therefore, we do not
believe that authorization of incidental take resulting from airborne
sound for pinnipeds is warranted, and airborne sound is not discussed
further here.
Potential Effects on Marine Mammal Habitat
The IBRP's proposed activities could have localized impacts on
marine mammal habitat, including prey, by increasing in-water SPLs.
Increased noise levels may affect acoustic habitat and adversely affect
marine mammal prey in the vicinity of the project areas (see discussion
below). Elevated levels of underwater noise would ensonify the project
areas where both fishes and mammals occur and could affect foraging
success. Additionally, marine mammals may avoid the area during the
proposed construction activities; however, seals and sea lions in the
area are typically transiting from the Pacific Ocean to haulouts and
foraging areas upstream, and are not expected to spend more than a few
days per year in the project area. Displacement due to noise is,
therefore, expected to be temporary and is not expected to result in
long-term effects to the individuals or populations.
The total area likely impacted by the IBRP's activities is
relatively small compared to the available habitat in the Columbia
River and nearby waterways. Avoidance by potential prey (i.e., fish) of
the immediate area due to increased noise is possible. The duration of
fish and marine mammal avoidance of this area after construction stops
is unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated. Any behavioral avoidance by fish or marine
mammals of the disturbed area would still leave significantly large
areas of fish and marine mammal foraging habitat in the nearby
vicinity.
The proposed project will occur in a relatively small portion of
the Columbia River and North Portland Harbor adjacent to existing
infrastructure. The habitat where the proposed project will occur is an
area of high vessel traffic and no known consistent prey aggregations
or haulouts, making it
[[Page 40510]]
relatively low quality habitat, which is typically used as a transit
corridor between the Pacific Ocean and upstream haulouts and foraging
sites. Temporary, intermittent, and short-term habitat alteration may
result from increased noise levels during the proposed construction
activities. Effects on marine mammals will be limited to temporary
displacement from pile installation and removal noise, and effects on
prey species will be similarly limited in time and space.
Water quality--Temporary and localized reduction in water quality
will occur as a result of in-water construction activities. Most of
this effect would occur during the installation and removal of piles
when bottom sediments are disturbed. The installation and removal of
piles would disturb bottom sediments and may cause a temporary increase
in suspended sediment in the project area. During pile extraction,
sediment attached to the pile moves vertically through the water column
until gravitational forces cause it to slough off under its own weight.
The small resulting sediment plume is expected to settle out of the
water column within a few hours. Studies of the effects of turbid water
on fish (marine mammal prey) suggest that concentrations of suspended
sediment can reach thousands of milligrams per liter before an acute
toxic reaction is expected (Burton, 1993).
Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Since the currents are so strong in the
area, following the completion of sediment-disturbing activities,
suspended sediments in the water column should dissipate and quickly
return to background levels in all construction scenarios. Turbidity
within the water column has the potential to reduce the level of oxygen
in the water and irritate the gills of prey fish species in the
proposed project area. However, turbidity plumes associated with the
project would be temporary and localized, and fish in the proposed
project area would be able to move away from and avoid the areas where
plumes may occur. Therefore, it is expected that the impacts on prey
fish species from turbidity, and therefore on marine mammals, would be
minimal and temporary. In general, the area likely impacted by the
proposed construction activities is relatively small compared to the
available marine mammal habitat in the Columbia River and associated
waterways.
Potential Effects on Prey. Sound may affect marine mammals through
impacts on the abundance, behavior, or distribution of prey species
(e.g., crustaceans, cephalopods, fishes, zooplankton). Marine mammal
prey varies by species, season, and location and, for some, is not well
documented. Studies regarding the effects of noise on known marine
mammal prey are described here.
Fishes utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. (Hastings and Popper, 2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fishes (e.g., Scholik and Yan, 2001, 2002; Popper and
Hastings, 2009). Several studies have demonstrated that impulse sounds
might affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g.,
Pe[ntilde]a et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman,
2009; Cott et al., 2012). More commonly, though, the impacts of noise
on fishes are temporary.
SPLs of sufficient strength have been known to cause injury to
fishes and fish mortality (summarized in Popper et al., 2014). However,
in most fish species, hair cells in the ear continuously regenerate and
loss of auditory function likely is restored when damaged cells are
replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of
4 to 6 dB was recoverable within 24 hours for one species. Impacts
would be most severe when the individual fish is close to the source
and when the duration of exposure is long. Injury caused by barotrauma
can range from slight to severe and can cause death, and is most likely
for fish with swim bladders. Barotrauma injuries have been documented
during controlled exposure to impact pile driving (Halvorsen et al.,
2012a; Casper et al., 2013, 2017).
Fish populations in the proposed project area that serve as marine
mammal prey could be temporarily affected by noise from pile
installation and removal. The frequency range in which fishes generally
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution
may change, especially with strong and/or intermittent sounds that
could harm fishes. High underwater SPLs have been documented to alter
behavior, cause hearing loss, and injure or kill individual fish by
causing serious internal injury (Hastings and Popper, 2005).
The greatest potential impact to marine mammal prey during
construction would occur during impact pile driving. However, the
duration of impact pile driving would be limited to the final stage of
installation (``proofing'') after the pile has been driven as close as
practicable to the design depth with a vibratory driver. Impact pile
driving would only occur during the in-water work window (September 15
through April 15 yearly), avoiding work during times when fishes would
be most vulnerable to effects of noise. Additionally, most impact
driving would be accomplished using a noise-attenuation system (bubble
curtain) designed to reduce the potentially injurious effects of
impulsive noise on fishes. Vibratory pile driving could elicit
behavioral reactions from fishes such as temporary avoidance of the
area but is unlikely to cause injuries to fishes or have persistent
effects on local fish populations. Construction also would have minimal
permanent and temporary impacts on benthic invertebrate species, a
marine mammal prey source. In addition, it should be noted that the
area in question is low-quality habitat since it is already highly
developed and experiences a high level of anthropogenic noise from
normal operations and other vessel traffic.
[[Page 40511]]
Potential Effects on Foraging Habitat
The IBR project is not expected to result in any habitat related
effects that could cause significant or long-term negative consequences
for individual marine mammals or their populations, since installation
and removal of in-water piles would be temporary and intermittent. The
total area affected by pile installation and removal is a very small
area compared to the foraging area available to marine mammals outside
this project area. The Columbia River and North Portland Harbor
waterways are not typical prey aggregation areas, are heavily used by
humans, and have no valuable haulout areas for pinnipeds. Seals and sea
lions in the area are typically transiting from the Pacific Ocean to
haulouts and foraging areas upstream. The area impacted by the project
is relatively small compared to the available habitat just outside the
project area, and there are no areas of particular importance that
would be impacted by this project. Any behavioral avoidance by fish of
the disturbed area would still leave significantly large areas of fish
and marine mammal foraging habitat in the nearby vicinity. As described
in the preceding, the potential for the IBRP's construction to affect
the availability of prey to marine mammals or to meaningfully impact
the quality of physical or acoustic habitat is considered to be
insignificant. Therefore, impacts of the project are not likely to have
adverse effects on marine mammal foraging habitat in the proposed
project area.
In summary, given the relatively small areas being affected, as
well as the temporary and mostly transitory nature of the proposed
construction activities, any adverse effects from the IBRP's activities
on prey habitat or prey populations are expected to be minor and
temporary. The most likely impact to fishes at the project site would
be temporary avoidance of the area. Any behavioral avoidance by fish of
the disturbed area would still leave significantly large areas of fish
and marine mammal foraging habitat in the nearby vicinity. Thus, we
preliminarily conclude that impacts of the specified activities are not
likely to have more than short-term adverse effects on any prey habitat
or populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant or long-term
consequences for individual marine mammals, or to contribute to adverse
impacts on their populations.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization under the regulations, which will inform
NMFS' consideration of ``small numbers,'' the negligible impact
determinations, and impacts on subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., impact and vibratory pile driving) has
the potential to result in disruption of behavioral patterns for
individual marine mammals. There is also some potential for auditory
injury (AUD INJ) (Level A harassment) to result, primarily for phocids
because predicted AUD INJ zones are larger than for otariids. The
proposed mitigation and monitoring measures are expected to minimize
the severity of the taking to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes the best
available science indicates marine mammals will likely be behaviorally
harassed or incur some degree of AUD INJ; (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the proposed
take estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS 2024)
as reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g.,
scientific sonar) sources. Generally speaking, Level B harassment take
estimates based on these behavioral harassment thresholds are expected
to include any likely takes by TTS as, in most cases, the likelihood of
TTS occurs at distances from the source less than those at which
behavioral harassment is likely. TTS of a sufficient degree can
manifest as behavioral harassment, as reduced hearing sensitivity and
the potential reduced opportunities to detect important signals
(conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
[[Page 40512]]
IBRP's proposed activity includes the use of continuous (vibratory)
and impulsive (impact) sources, and therefore the RMS SPL thresholds of
120 and 160 dB re 1 [mu]Pa are applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive),
shown in table 9. IBRP's proposed activity includes the use of
impulsive (impact) and non-impulsive (vibratory) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in the table below. The references, analysis,
and methodology used in the development of the criteria are described
in NMFS' 2024 Updated Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools.
Table 9--Thresholds Identifying the Onset of Auditory Injury
----------------------------------------------------------------------------------------------------------------
AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [micro]Pa\2\s. In this Table, criteria are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017; ISO 2020). The
subscript ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within
the generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated
with cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting
function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is
24 hours. The weighted cumulative sound exposure level criteria could be exceeded in a multitude of ways
(i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents
to indicate the conditions under which these criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Pile driving generates underwater noise that can potentially result in
disturbance to marine mammals in the project area. The maximum
(underwater) area ensonified is determined by the topography of the
Columbia River and North Portland Harbor, including intersecting land
masses that will reduce the overall area of potential impact.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B x Log10 (R1/R2),
Where
TL = transmission loss in dB;
B = transmission loss coefficient; for practical spreading equals
15;
R1 = the distance of the modeled SPL from the driven
pile; and,
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6-dB reduction in sound level for each doubling of
distance from the source (20xlog10[range]). Cylindrical
spreading occurs in an environment in which sound propagation is
bounded by the water surface and sea bottom, resulting in a reduction
of 3 dB in sound level for each doubling of distance from the source
(10xlog10[range]). A practical spreading value of 15 is
often used under conditions, such as the project site, where water
increases with depth as the receiver moves away from the shoreline,
resulting in an expected propagation environment that would lie between
spherical and cylindrical spreading loss conditions. Practical
spreading loss is assumed here.
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. In order to calculate
the distances to the Level A harassment and the Level B harassment
sound thresholds for the methods and piles being used in this project,
NMFS used acoustic monitoring data from other locations to develop
proxy source levels for the various pile types, sizes and methods
(table 10). Generally, we choose source levels from similar pile types
from locations (e.g., geology, bathymetry) similar to the project.
[[Page 40513]]
Table 10--Proxy Sound Source Levels and References
--------------------------------------------------------------------------------------------------------------------------------------------------------
Attenuated or Peak SPL (re 1 RMS SPL (re 1 SEL (re 1 Reference for proxy
Pile type and size unattenuated \1\ Single or concurrent [mu]Pa) [mu]Pa) [mu]Pa \2\-s ) source value
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel pipe.................. Unattenuated......... Single............... 205 190 175 DEA (2011).
Attenuated........... Single............... 198 183 168
Concurrent \2\ \3\... 198 186 168
48-in steel pipe.................. Unattenuated......... Single............... 214 201 184
Attenuated........... Single............... 207 194 177
Concurrent \2\ \3\... 207 197 177
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel pipe.................. Unattenuated......... Single............... .............. 175 .............. CALTRANS (2020).
Concurrent \3\....... .............. 178
48-in steel pipe.................. Unattenuated......... Single............... .............. 175
Concurrent \3\....... .............. 178
Steel sheet....................... Unattenuated......... Single............... .............. 175
Concurrent \3\....... .............. 178
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Bubble curtain effectiveness of 7 dB was assumed based on previous monitoring results from the Columbia River Crossing project.
\2\ Concurrent impact driving of one 48-in and one 24-in steel pipe pile was conservatively analyzed as if two 48-in piles were driven concurrently.
\3\ Proxy values for single piles were added according to the rules of decibel addition to develop proxy levels for concurrent driving.
\4\ The proxy source level used for vibratory driving in this analysis is conservative; most source measurements for vibratory pile driving are at or
below 170 dB RMS.
For this project, two hammers, including any combination of
vibratory and impact hammers, may operate simultaneously. The
calculated proxy source levels for the different potential concurrent
pile driving scenarios are shown in table 10.
Two Impact Hammers
For simultaneous impact driving of two 48-in steel pipe piles (the
most conservative scenario), the number of strikes per pile was doubled
to estimate total sound exposure during simultaneous installation.
While the likelihood of impact pile driving strikes completely
overlapping in time is rare due to the intermittent nature and short
duration of strikes, NMFS conservatively estimates that up to 20
percent of strikes may overlap completely in time. Therefore, to
calculate Level B harassment isopleths for simultaneous impact pile
driving, dB addition (if the difference between the two sound source
levels is between 0 and 1 dB, 3 dB are added to the higher sound source
level) was used to calculate the combined sound source level of 197 dB
RMS.
One Impact Hammer, One Vibratory Hammer
To calculate Level B harassment isopleths for one impact and one
vibratory hammer operating simultaneously, sources were treated as
though they were non-overlapping and the isopleth associated with the
individual source which results in the largest Level B harassment
isopleth was conservatively used for both sources to account for
periods of overlapping activities.
Two Vibratory Hammers
To calculate Level B harassment isopleths for two simultaneous
vibratory hammers, the NMFS User Spreadsheet tool was used with
modified inputs to account for accumulation, weighting, and source
overlap in space and time. Using the rules of dB addition (if the
difference between the two sound source levels is between 0 and 1 dB, 3
dB are added to the higher sound source level), the combined sound
source level for the simultaneous vibratory installation of any two
piles is 178 dB RMS.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional user
spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources like pile driving, the optional user spreadsheet
tool predicts the distance at which, if a marine mammal remained at
that distance for the duration of the activity, it would be expected to
incur AUD INJ. Inputs used in the optional user spreadsheet tool, and
the resulting estimated isopleths, are reported below.
To calculate Level A harassment isopleths for two impact hammers
operating simultaneously, the NMFS User Spreadsheet calculator was used
with modified inputs to account for the total estimated number of
strikes for all piles. For concurrent impact driving of two identical
steel pipe piles (the most conservative scenario), the number of
strikes per pile was doubled while holding the number of piles per day
constant at one. The source level for two simultaneous impact hammers
was not adjusted because for identical sources the accumulation of
energy depends only on the total number of strikes, whether or not they
overlap fully in time. Therefore, the source level used for two
simultaneous impact hammers was 177 dB SELss for 48-in
piles, and 168 dB SELss for two 24-in piles.
To calculate Level A harassment isopleths of one impact hammer and
one vibratory hammer operating simultaneously, sources were treated as
though they were non-overlapping and the isopleth associated with the
individual source which resulted in the
[[Page 40514]]
largest Level A harassment isopleth was conservatively used for both
sources to account for periods of overlapping activities.
To calculate Level A harassment isopleths of two vibratory hammers
operating simultaneously, the NMFS acoustic threshold calculator was
used with modified inputs to account for accumulation, weighting, and
source overlap in space and time. Using the rules of dB addition (NMFS,
2024; if the difference between the two sound source levels is between
0 and 1 dB, 3 dB are added to the higher sound source level), the
combined sound source level for the simultaneous vibratory installation
of two piles is 178 dB RMS.
Table 11--NMFS User Spreadsheet Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Weighting
factor Number of Daily duration Number of Maximum
Pile size and type Spreadsheet tab used adjustment piles per day (minutes) strikes per strikes per
(kHz) pile day
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel pipe (Unattenuated, single)... E.1. Impact pile driving.... 2.0 1 10 75 75
24-in steel pipe (Attenuated, single)..... 3 .............. 300 900
24-in and 24-in steel pipes (Attenuated, 6 .............. 300 1,800
concurrent).
48-in steel pipe (Unattenuated, single)... 1 10 75 75
48-in steel pipe (Attenuated, single)..... 3 .............. 300 900
48-in and 24-in or 48-in steel pipes 6 .............. 300 1,800
(Attenuated, concurrent).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Pile Installation and Extraction
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel pipe (Unattenuated, single)... A.1. Vibratory pile driving. 2.5 .............. 600 .............. ..............
48-in steel pipe (Unattenuated, single)... .............. 600 .............. ..............
Steel sheet (Unattenuated, single)........ .............. 600 .............. ..............
24-in and or 48-in and or sheet .............. 600 .............. ..............
(Unattenuated, concurrent).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 12--Calculated Level A and B Harassment Isopleths in the Columbia
River
------------------------------------------------------------------------
Level A
harassment zone
(m/km \2\) Level B
Pile size and type ------------------- harassment zone
Phocids & (m/km \2\)
Otariids \a\
------------------------------------------------------------------------
Impact Pile Installation--unattenuated
------------------------------------------------------------------------
24-in steel pipe (Unattenuated, 46 1,000
single).......................... >0.01 1.59
48-in steel pipe (Unattenuated, 183.3 5,412
single).......................... 0.11 9.29
------------------------------------------------------------------------
Impact Pile Installation--attenuated
------------------------------------------------------------------------
24-in steel pipe (Attenuated, 82.4 341
single).......................... 0.02 0.37
24-in and 24-in steel pipes 130.8 541
(Attenuated, concurrent)......... 0.11 0.86
48-in steel pipe (Attenuated, 328 1,848
single).......................... 0.34 3.12
48-in and 24-in or 48-in steel 520.7 2,929
pipes (Attenuated, concurrent)... 0.83 4.82
------------------------------------------------------------------------
Vibratory Pile Installation and Extraction
------------------------------------------------------------------------
24-in steel pipe (Unattenuated, 236.3 46,414
single).......................... 0.18 \b\ 17.63
48-in steel pipe (Unattenuated, ................. .................
single)..........................
Steel sheet (Unattenuated, single) ................. .................
24-in and or 48-in and or sheet 374.5 73,564
(Unattenuated, concurrent)....... 0.58 \b\ 17.63
------------------------------------------------------------------------
\a\ Level A harassment zones for phocids have been conservatively
applied to both phocids and otariids in this analysis.
\b\ Level B harassment ensonified areas are limited by the river
curvature and geography.
[[Page 40515]]
Table 13--Calculated Level A and B Harassment Isopleths in the North
Portland Harbor
------------------------------------------------------------------------
Level A
harassment zone
(m/km\2\) Level B
Pile size and type ------------------- harassment zone
Phocids & (m/km\2\)
Otariids \a\
------------------------------------------------------------------------
Impact Pile Installation--unattenuated
------------------------------------------------------------------------
24-in steel pipe (Unattenuated, 46 1,000
single).......................... >0.01 0.6
48-in steel pipe (Unattenuated, 183.3 5,412
single).......................... 0.09 2.26
------------------------------------------------------------------------
Impact Pile Installation--attenuated
------------------------------------------------------------------------
24-in steel pipe (Attenuated, 82.4 341
single).......................... 0.02 0.19
24-in and 24-in steel pipes 130.8 541
(Attenuated, concurrent)......... 0.07 0.34
48-in steel pipe (Attenuated, 328 1,848
single).......................... 0.18 1.1
48-in and 24-in or 48-in steel 520.7 2,929
pipes (Attenuated, concurrent)... 0.33 1.69
------------------------------------------------------------------------
Vibratory Pile Installation and Extraction
------------------------------------------------------------------------
24-in steel pipe (Unattenuated, 236.3 46,414
single).......................... 0.12 \b\ 2.25
48-in steel pipe (Unattenuated, ................. .................
single)..........................
Steel sheet (Unattenuated, single) ................. .................
24-in and or 48-in and or sheet 374.5 73,564
(Unattenuated, concurrent)....... 0.22 \b\ 2.25
------------------------------------------------------------------------
\a\ Level A harassment zones for phocids have been conservatively
applied to both phocids and otariids in this analysis.
\b\ Level B ensonified areas are limited by the harbor geography.
Marine Mammal Occurrence
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. To ensure use of the best and most
current marine mammal data, NMFS inquired about current sightings data
from the ODFW and the WDFW in October 2024. These agencies provided
information about the relative use of haulout areas and seasonality of
pinniped presence in the Columbia and Willamette Rivers. Specifically,
they listed major haulouts at the mouth of the Cowlitz River and the
city of Rainier docks (38 mi; 62 km from the project site), and
Bonneville Dam (37.5 mi; 60 km), with semi-regular haulouts at Coffin
Rock (33 mi; 53 km), Powerline Islands (13 mi; 22 km), and Phoca Rock
(25.5 mi; 41 km) (see figure 2). The peak seasonal presence noted was
February through May, though sea lions are often present at Bonneville
Dam in other months.
[[Page 40516]]
[GRAPHIC] [TIFF OMITTED] TP19AU25.002
Figure 2--Pinniped Haulout Locations Along the Columbia River Between
the Cowlitz/Kalama Rivers and Bonneville Dam
One of the best sources of current abundance data for California
sea lions and Steller sea lions within the Columbia River is the most
recent USACE report on pinniped presence and salmonid predation at
Bonneville Dam, which reports data from pinniped monitoring conducted
in 2022 (Tidwell et al., 2023). These data provide the best estimate of
the number of sea lions that transit the project site in a given year,
as each sea lion that transits that project site is likely traveling to
or from Bonneville Dam and, therefore, captured in the annual counts.
Each animal counted at the dam would transit the project site twice in
a given season. However, the USACE Bonneville Dam monitoring data
likely underestimates the density of harbor seals that transit or are
present at the project site. Harbor seals are relatively more common in
the lower reaches of the river but are only occasionally observed as
far upriver as Bonneville Dam.
In November 2024, NMFS received unpublished 2021-2024 pinniped
abundance monitoring data for the Lower Columbia and Willamette Rivers
from ODFW in collaboration with the Columbia River Inter-Tribal Fish
Commission (CRITFC), and 2021-2024 Bonneville Dam pinniped counts from
the USACE. CRIFTC data were taken via boat-based or aerial surveys of
known pinniped haulouts along the Columbia and Willamette Rivers, and
presented data on pinnipeds as a guild, not separated by species.
NMFS compiled these various datasets and analyzed sightings between
the Bonneville Dam upriver of the project site, and Longview, WA, 46 mi
(74 km) downriver. These data represent the anticipated average maximum
number of daily pinniped transits within the portion of the Columbia
River at the bridge location for each month of the year. Table 14 shows
average estimated monthly occurrence of pinnipeds in three regions:
downstream (Longview, WA to the Willamette river); the project area
(Willamette River/Portland area); and upstream (Portland to Bonneville
Dam). Downstream sites had significantly more pinniped sightings than
upstream sites. From these data, NMFS conservatively used the maximum
of the project area and upstream estimates as a proxy for monthly
pinniped occurrence (table 14). Data were further condensed to evaluate
pinniped presence for the two key periods of interest (fall and spring
migrations as defined at Bonneville Dam) for the purpose of estimating
incidental take (September through April, and May through August).
Table 14--Daily Occurrence Estimates by Month for the Columbia River between Longview, WA and the Bonneville
Dam, and Maximum Occurrences Used in Take Estimations
----------------------------------------------------------------------------------------------------------------
Upstream (RM Maximum Seasonal
Downstream (RM Project area 115 to 146) occurrence occurrence
66 to 110) (RM 110 to (Bonneville (pinnipeds per (pinnipeds per
115) Dam) day) day)
----------------------------------------------------------------------------------------------------------------
September....................... - 1 15 15 15.2
October......................... - 3.3 10 10
November........................ - 1.6 16.5 16.5
[[Page 40517]]
December........................ 3 5.9 11.85 11.9
January......................... 81.4 4.4 2.15 4.4
February........................ 86.7 10.7 1.5 10.7
March........................... 207.5 3.4 9.65 9.7
April........................... 18.6 5.5 43.3 43.3
May............................. 4.3 4.8 14.7 14.7 6.7
June............................ - 1 0 1
July............................ - - 1 1
August.......................... 56 - 10 10
----------------------------------------------------------------------------------------------------------------
Note: ``-'' means no sightings data were available for this region and month; RM means river mile.
Take Estimation
Here we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and proposed for authorization. The majority of the
recent data obtained from ODFW and WDFW did not separate pinniped
sightings by species. Thus, NMFS calculated occurrence rates for all
three expected pinniped species as a guild (table 14).
Not all animals passing through the IBR project area are expected
to be exposed to noise levels equated with take by Level A or Level B
harassment. IBRP proposed and NMFS concurs with the exposure estimates
shown in table 15. Animals in the project area are typically transiting
through on their way to or from upriver haulouts and or foraging areas.
While most of the activities will ensonify the full width of the river
and or harbor, some animals will pass by the project site when no
active pile driving is occurring, thus reducing the expected exposure
percentages.
Table 15--Exposure Estimates by Activity for Transiting Pinnipeds
----------------------------------------------------------------------------------------------------------------
Level A harassment Level B harassment
-------------------------------------------------------------------------------
Percentage (%) Rationale Percentage (%) Rationale
----------------------------------------------------------------------------------------------------------------
Unattenuated impact pile 5................. Very few 50................ Very few
installation. days of activity days of activity
per year. per year.
Very Very
short duration short duration
activity. activity.
Attenuated impact pile 10................ 50................
installation. Relatively short Relatively short
duration activity. duration
activity.
Ensonified area
can be avoided by Ensonified area
transiting cannot be avoided
pinnipeds in most during activity.
pile driving
scenarios.
Vibratory pile installation and 0................. Extended 75................
extraction. (~24 hours) Ensonified area
exposure would be cannot be avoided
required to reach during activity.
Level A
harassment
threshold;
unlikely for
transiting
pinnipeds.
----------------------------------------------------------------------------------------------------------------
The formula used for calculating estimated takes by both Level A
and Level B harassment for each relevant activity is:
Incidental take estimate = number of days of Activity 1 x estimated
number of animals per day x exposure percentage (Level A or Level B)
for activity 1.
Estimated take by Level A and Level B harassment proposed to be
authorized for each year of the IBR project is shown in table 16.
Because occurrence estimates are only available at the guild level,
take estimates are not calculated to the species level, and it is
assumed that all takes could come from any of the three stocks. This
results in an overestimate of the percentage of each stock taken.
[[Page 40518]]
Table 16--Proposed Take by Level A and Level B Harassment for All Pinnipeds Over the Course of the 5-year LOA
----------------------------------------------------------------------------------------------------------------
Activity Year Level A Level B Total
----------------------------------------------------------------------------------------------------------------
Impact--Unattenuated.................. 1....................... 8 76 84
2....................... 4 38 42
3....................... 4 38 42
4....................... 4 38 42
5....................... 4 38 42
5-Year Estimate......... 24 228 252
Impact--Attenuated.................... 1....................... 182 912 1,094
2....................... 152 760 912
3....................... 114 570 684
4....................... 114 570 684
5....................... 114 570 684
5-Year Estimate......... 676 3,382 4,058
Vibratory............................. 1....................... 0 2,713 2,713
2....................... 0 2,713 2,713
3....................... 0 2,713 2,713
4....................... 0 2,713 2,713
5....................... 0 2,713 2,713
5-Year Total............ 0 13,365 13,365
----------------------------------------------------------------------------------------------------------------
All Activities Totals
----------------------------------------------------------------------------------------------------------------
Maximum Annual.......... 190 3,701 3,891
5-Year Total............ 700 17,175 17,875
----------------------------------------------------------------------------------------------------------------
Table 17--Proposed Take Estimates and Percentage of Stocks Taken in the Year of Maximum Annual Take
----------------------------------------------------------------------------------------------------------------
Maximum annual estimated take
Species ------------------------------------------------ Percent of
Level A Level B Total stock \a\ (%)
----------------------------------------------------------------------------------------------------------------
Harbor seal \b\................................. 190 3,701 3,891 17.3
California sea lion. 1.5
Steller sea lion. 10.7
----------------------------------------------------------------------------------------------------------------
\a\ NMFS conservatively assumes that all proposed estimated takes could come from a single stock due to the
inability to distinguish between species detected during surveys. In reality, takes will occur to all three
stocks and the percentages shown are thus overestimates.
\b\ The SAR lists the abundance for this stock as unknown; Pearson et al., 2024 report an estimate of 22,549,
which we used in this analysis.
Proposed Mitigation
In order to promulgate a rulemaking under section 101(a)(5)(A) of
the MMPA, NMFS must set forth the permissible methods of taking
pursuant to the activity, and other means of effecting the least
practicable impact on the species or stock and its habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stock for
taking for certain subsistence uses (latter not applicable for this
action). NMFS regulations require applicants for incidental take
authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned); and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost and impact on
operations.
The mitigation requirements described in the following were
proposed by IBRP, which has agreed that all of the mitigation measures
are practicable. As required by the MMPA, NMFS concurred that these
measures are sufficient to achieve the least practicable adverse impact
on the affected marine mammal species or stocks and their habitat. NMFS
describes these below as proposed mitigation requirements, and has
included them in the proposed regulations.
In addition to the measures described later in this section, the
IBRP would follow these general mitigation measures:
Authorized take, by Level A and Level B harassment only,
would be limited to the species and numbers listed in Table 16.
Construction activities must be halted upon observation of either a
species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met, entering or is within the harassment zone.
The taking by serious injury or death of any of the
species listed in table 18 or any taking of any other species of marine
mammal would be
[[Page 40519]]
prohibited and would result in the modification, suspension, or
revocation of the ITR and associated LOA, if issued. Any taking
exceeding the authorized amounts listed in table 16 would be prohibited
and would result in the modification, suspension, or revocation of the
ITR and associated LOA, if issued.
Ensure that construction supervisors and crews, the marine
mammal monitoring team, and relevant IBRP staff are trained prior to
the start of all construction activities, so that responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures are clearly understood. New personnel joining
during the project must be trained prior to commencing work;
The IBRP, construction supervisors and crews, Protected
Species Observers (PSOs), and relevant IBRP staff must avoid direct
physical interaction with marine mammals during construction activity.
If a marine mammal comes within 10 m of such activity, operations must
cease and vessels must reduce speed to the minimum level required to
maintain steerage and safe working conditions, as necessary to avoid
direct physical interaction.
Employ PSOs and establish monitoring locations as
described in section 5 of the IHA and the IBRP's Marine Mammal
Monitoring and Mitigation Plan (see appendix A of the IBRP's
application). The IBRP must monitor the project area to the maximum
extent possible based on the required number of PSOs, required
monitoring locations, and environmental conditions;
Additionally, the following mitigation measures apply to the IBRP's
in-water construction activities:
Establishment of Shutdown Zones--The IBRP would establish shutdown
zones with radial distances as identified in table 18 for all
construction activities. If a marine mammal is observed entering or
within the shutdown zones indicated in table 18, pile driving activity
must be delayed or halted. If pile driving is delayed or halted due to
the presence of a marine mammal, the activity may not commence or
resume until either the animal has voluntarily exited and been visually
confirmed beyond the shutdown zones or 15 minutes have passed without
re-detection of the animal.
Table 18--Proposed Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
Monitoring zones (m)
Activity Pile type/size Shutdown zone --------------------------------------
(m) Level A Level B
----------------------------------------------------------------------------------------------------------------
Impact--Unattenuated (Single 24-in................ 10 46 1,000
Hammer). 48-in................ 184 5,412
Impact--Attenuated (Single Hammer) 24-in................ 10 83 341
48-in................ 328 1,848
Impact--Attenuated (Two Hammers).. 24-in................ 10 131 541
48-in................ 521 2,929
Vibratory (Single Hammer)......... 24-in, 48-in, and 10 (\a\) 18,593 (upstream).\b\
Vibratory (Two Hammers)........... sheet. 8,230
24-in, 48-in, and (downstream).\b\
sheet.
----------------------------------------------------------------------------------------------------------------
Notes: cm = centimeter(s), m = meter(s).
\a\ While the results of the underwater noise modeling indicate Level A harassment isopleths exist for
cumulative exposure to underwater noise during vibratory pile driving, take by Level A harassment is not
anticipated, and no Level A harassment Monitoring Zone is proposed for vibratory pile driving.
\b\ PSOs will monitor the Level B harassment zone to the extent possible based on positioning and environmental
conditions.
Pre- and Post-Activity Monitoring--Monitoring would take place from
30 minutes prior to initiation of pile driving activity (i.e., pre-
start clearance monitoring) through 30 minutes post-completion of pile
driving activity. In addition, monitoring for 30 minutes would take
place whenever a break in the specified activity (i.e., impact pile
driving, vibratory pile driving) of 30 minutes or longer occurs. Pre-
start clearance monitoring would be conducted during periods of
visibility sufficient for the lead PSO to determine that the shutdown
zones indicated in table 18 are clear of marine mammals. Pile driving
may commence following 30 minutes of observation when the determination
is made that the shutdown zones are clear of marine mammals.
Soft Start--The IBRP would use soft start techniques when impact
pile driving. Soft start requires contractors to provide an initial set
of three strikes at reduced energy, followed by a 30-second waiting
period, then two subsequent reduced-energy strike sets. A soft start
would be implemented at the start of each day's impact pile driving and
at any time following cessation of impact pile driving for a period of
30 minutes or longer. Soft start procedures are used to provide
additional protection to marine mammals by providing warning and/or
giving marine mammals a chance to leave the area prior to the hammer
operating at full capacity.
Noise Attenuation System
The IBRP would use a bubble curtain during impact pile driving in
water depths greater than 0.67 m. The bubble curtain would be operated
as necessary to achieve optimal performance. At a minimum, the bubble
curtain would distribute air bubbles around 100 percent of the piling
circumference for the full depth of the water column, the lowest bubble
ring would be in contact with the substrate for the full circumference
of the ring, and the weights attached to the bottom ring would ensure
100 percent substrate contact. No parts of the ring or other objects
would prevent full substrate contact. In addition, air flow to the
bubblers would be balanced around the circumference of the pile.
A hydroacoustic monitoring plan would be implemented during impact
pile driving to confirm the attenuation device is installed and
functioning as designed. This monitoring program would require some
unattenuated pile strikes to confirm the amount of attenuation provided
by the system. Some amount of unattenuated pile strikes are also
factored in to account for periods when the bubble curtain may not be
providing sufficient attenuation. IBRP estimates that up to 75
unattenuated strikes may be required for a period of approximately 10
minutes approximately 1 day per week. Testing would occur on up to
approximately 30 days during the five year period covered under this
LOA, and on approximately
[[Page 40520]]
40 days total over the course of the in-water construction period.
Hydroacoustic Monitoring--The IBRP would conduct hydroacoustic
monitoring to verify the predicted sound source levels and the
effectiveness of the bubble curtain. An acoustic monitoring plan would
be submitted to NMFS no later than 60 days prior to the beginning of
impact pile driving for approval.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to promulgate a rulemaking for an activity, section
101(a)(5)(A) of the MMPA states that NMFS must set forth requirements
pertaining to the monitoring and reporting of such taking. The MMPA
implementing regulations at 50 CFR 216.104(a)(13) indicate that
requests for authorizations must include the suggested means of
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species and of the level of taking or
impacts on populations of marine mammals that are expected to be
present while conducting the activities. Effective reporting is
critical both to compliance as well as ensuring that the most value is
obtained from the required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
Mitigation and monitoring effectiveness.
The monitoring and reporting requirements described in the
following were proposed by IBRP, which has agreed that all of the
requirements are practicable. NMFS describes these below as proposed
requirements, and has included them in the proposed regulations.
The IBRP would abide by all monitoring and reporting measures
contained within the IHA, if issued, and their Marine Mammal Monitoring
and Mitigation Plan (see appendix A of the IBRP's application). A
summary of those measures and additional requirements proposed by NMFS
is provided below.
Visual Monitoring--A minimum of two NMFS-approved PSOs must be
stationed at monitoring locations as established in the marine mammal
monitoring plan (see appendix A of the IBRP's LOA application) for the
entirety of active pile driving operations. PSOs would be independent
of the activity contractor (for example, employed by a subcontractor)
and have no other assigned tasks during monitoring periods. At least
one PSO would have prior experience performing the duties of a PSO
during an activity pursuant to a NMFS-issued incidental take
authorization (ITA) or letter of concurrence (LOC). Other PSOs may
substitute other relevant experience, education (degree in biological
science or related field), or training for prior experience performing
the duties of a PSO during construction activity pursuant to a NMFS-
issued incidental take authorization.
One of the PSOs would be responsible for monitoring the shutdown
zone and will be stationed in a location with clear line of sight views
of the entire shutdown zone. The second PSO will be responsible for
monitoring the Level A and B monitoring zones. This PSO will be
stationed in a location with clear line of sight views of the entire
Level A monitoring zone. This PSO need not be able to observe the
entire Level B monitoring zone, but they need to be able to observe the
full width of the river and be able to spot and identify marine mammals
passing through the Level B monitoring zone.
Where a team of three or more PSOs is required, a lead observer or
monitoring coordinator would be designated. The lead observer must have
prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued ITA or LOC.
PSOs should also have the following additional qualifications:
The ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to: (1) the number and species
of marine mammals observed; (2) dates and times when in-water
construction activities were conducted; (3) dates, times, and reason
for implementation of mitigation (or why mitigation was not implemented
when required); and (4) marine mammal behavior; and
The ability to communicate orally, by radio or in person,
with project personnel to provide real-time information on marine
mammals observed in the area as necessary.
Acoustic Monitoring
The IBRP must establish acoustic monitoring procedures as described
in an acoustic monitoring plan, to be submitted to NMFS for approval no
less than 60 days prior to the commencement of impact pile driving. At
minimum, the hydroacoustic monitoring plan would include:
A close range hydrophone placed at a horizontal distance
of 10 m from the pile. Additional hydrophones may be placed at (1) a
horizontal distance no less than three times the water depth and (2) in
the far field, well away from the source. Hydrophones would be placed
at a depth of half the water depth at each measurement location. Exact
positioning of the hydrophone(s) would ensure a direct, unobstructed
path between the sound source and the hydrophone(s);
Measurement systems would be deployed using configurations
which minimize self or platform noise and ensure stable positioning
throughout the recordings;
The recordings would be continuous throughout each
acoustic event for which monitoring is required;
[[Page 40521]]
The SSV measurement systems would have a sensitivity
appropriate for the expected SPLs. The frequency range of SSV
measurement systems would cover the range of at least 20 Hz to 20 kHz.
The dynamic range of the measurement system would be sufficient such
that at each location, the signals would avoid poor signal-to-noise
ratios for low amplitude signals, and would avoid clipping,
nonlinearity, and saturation for high amplitude signals;
All hydrophones used in SSV measurements systems would be
required to have undergone a full system laboratory calibration
conforming to a recognized standard procedure, from a factory or
accredited source to ensure the hydrophone(s) receives accurate SPLs,
at a date not to exceed 2 years before deployment. Additional in-situ
calibration checks using a pistonphone would be required to be
performed before and after each hydrophone deployment. If the
measurement system employs filters via hardware or software (e.g.,
high-pass, low-pass, etc.), which are not already accounted for by the
calibration, the filter performance (i.e., the filter's frequency
response) would be reported, and the data corrected before analysis;
Environmental data would be collected, including but not
limited to, the following: wind speed and direction, air temperature,
humidity, surface water temperature, water depth, wave height, weather
conditions, and other factors that could contribute to influencing the
airborne and underwater SPLs (e.g., aircraft, boats, etc.); and
The project engineer would supply the acoustics specialist
with the substrate composition, hammer model and size, hammer energy
settings, and any changes to those settings during the monitoring.
For acoustically monitored construction activities, data from the
continuous monitoring locations would be post-processed to obtain the
following sound measures:
Maximum peak sound pressure level recorded for all
activities, expressed in dB re 1 [mu]Pa. This maximum value will
originate from the phase of hammering during which hammer energy was
also at maximum.
From all activities occurring during the time that the
hammer was at maximum energy, these additional measures will be made,
as appropriate:
[cir] Mean, median, minimum, and maximum RMS SPL (dB re 1 [mu]Pa);
[cir] Mean duration of a pile strike (based on the 90 percent
energy criterion);
[cir] Number of hammer strikes;
[cir] Mean, median, minimum, and maximum SELss (dB re
[mu]Pa\2\ sec);
[cir] Median integration time used to calculate RMS SPL (for
vibratory monitoring, the time period selected is 1-second intervals.
For impulsive monitoring, the time period is 90 percent of the energy
pulse duration);
[cir] A frequency spectrum (power spectral density) (dB re
[mu]Pa\2\ per Hz) based on all strikes with similar sound. Spectral
resolution would be 1 Hz, and the spectrum would cover nominal range
from 20 Hz to 20 kHz;
[cir] Finally, the SEL24 would be computed from all the
strikes associated with each pile occurring during all phases, i.e.,
soft start. This measure is defined as the sum of all SELss
values. The sum is taken of the antilog, with log10 taken of
result to express (dB re [mu]Pa\2\ sec).
Reporting--The IBRP would be required to submit an annual draft
summary report on all construction activities and marine mammal
monitoring results to NMFS within 90 days following the end of each
construction year. Additionally, a draft comprehensive 5-year summary
report must be submitted to NMFS within 90 days of the end of the
project. The annual reports would include an overall description of
construction work completed, a narrative regarding marine mammal
sightings, and associated raw PSO data sheets (in a queryable
electronic format). Specifically, the reports must include:
Dates and times (begin and end) of all marine mammal
monitoring;
Construction activities occurring during each daily
observation period, including: (a) how many and what type of piles were
driven or removed and the method (i.e., impact or vibratory); and (b)
the total duration of time for each pile (vibratory driving) or number
of strikes for each pile (impact driving);
PSO locations during marine mammal monitoring; and
Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance.
Upon observation of a marine mammal the following information must
be reported:
Name of PSO who sighted the animal(s) and PSO location and
activity at the time of the sighting;
Time of the sighting;
Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
Distance and bearing of each observed marine mammal
relative to the pile being driven or removed for each sighting;
Estimated number of animals (min/max/best estimate);
Estimated number of animals by cohort (e.g., adults,
juveniles, neonates, group composition, etc.);
Animal's closest point of approach and estimated time
spent within the estimated harassment zone(s);
Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
Number of marine mammals detected within the estimated
harassment zones, by species; and
Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specified
actions that ensured, and resulting changes in behavior of the
animal(s), if any.
Acoustic monitoring report(s) must be submitted on the same
schedule as visual monitoring reports (i.e., within 90 days following
the completion of construction). The acoustic monitoring report must
contain the informational elements described in the acoustic monitoring
plan and, at minimum, must include:
Hydrophone equipment and methods: (1) recording device,
sampling rate, calibration details, distance (m) from the pile where
recordings were made; and (2) the depth of water and recording
device(s);
Location, identifier, orientation (e.g., vertical,
battered), material, and geometry (shape, diameter, thickness, length)
of pile being driven, substrate type, method of driving during
recordings (e.g., hammer model and energy), and total pile driving
duration;
Whether a sound attenuation device is used and, if so, a
detailed description of the device used, its distance from the pile and
hydrophone, and the duration of its use per pile;
For impact pile driving: (1) number of strikes per day and
per pile and strike rate; (2) depth of substrate to penetrate; (3)
decidecade (one-third octave) band spectra in tabular and figure
formats computed on a per-pulse basis, including the arithmetic mean or
median for all computed spectra; (4) pulse duration and median, mean,
maximum, minimum, and number of
[[Page 40522]]
samples (where relevant) of the following sound level metrics: (5) RMS
SPL; (6) SEL24, peak (PK) SPL, and SELss; and
For any monitored vibratory pile driving: (1) duration of
driving for each pile; (2) depth of substrate to penetrate; (3)
decidecade (one-third octave) band spectra in tabular and figure
formats, including the arithmetic mean or median for all computed
spectra; (4) duration and median, mean, maximum, minimum, and number of
samples (where relevant) of the following level metrics: RMS SPL;
SEL24; peak (PK) SPL; and SELss.
If no comments are received from NMFS within 30 days after the
submission of the draft summary report, the draft report would
constitute the final report. If the IBRP received comments from NMFS, a
final summary report addressing NMFS' comments would be submitted
within 30 days after receipt of comments. The estimated harassment and
shutdown zones (table 18) may be modified with NMFS' approval following
NMFS' acceptance of an acoustic monitoring report.
Reporting Injured or Dead Marine Mammals--In the event that
personnel involved in the IBRP's activities discover an injured or dead
marine mammal, the IBRP would report the incident to the NMFS Office of
Protected Resources (OPR) ([email protected],
[email protected]) and to the West Coast Regional Stranding
Coordinator as soon as feasible. If the death or injury was clearly
caused by the specified activity, the IBRP would immediately cease the
specified activities until NMFS is able to review the circumstances of
the incident and determine what, if any, additional measures are
appropriate to ensure compliance with the IHA. The IBRP would not
resume their activities until notified by NMFS. The report would
include the following information:
Description of the incident;
Environmental conditions (e.g., Beaufort sea state,
visibility);
Description of all marine mammal observations in the 24
hours preceding the incident;
Photographs or video footage of the animal(s) (if
equipment is available).
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive; and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to
harbor seal, California sea lion, and Steller sea lion, given that the
anticipated effects of this activity on these different marine mammal
stocks are expected to be similar. There is little information about
the nature or severity of the impacts, or the size, status, or
structure of any of these species or stocks that would lead to a
different analysis for this activity.
NMFS has identified key factors which may be employed to assess the
level of analysis necessary to conclude whether potential impacts
associated with a specified activity should be considered negligible.
These include, but are not limited to, the type and magnitude of
taking, the amount and importance of the available habitat for the
species or stock that is affected, the duration of the anticipated
effect to the species or stock, and the status of the species or stock.
The potential effects of the specified activities on California sea
lions, Steller sea lions, and harbor seals are discussed below.
Pile driving associated with the IBR project, as outlined
previously, has the potential to disturb or displace marine mammals.
Specifically, the specified activities may result in take, in the form
of Level B harassment and, for some individuals, Level A harassment,
from underwater sounds generated by pile driving. Potential takes could
occur if marine mammals are present in zones ensonified above the
thresholds for Level B harassment or Level A harassment, identified
above, while activities are underway.
The IBRP's proposed activities and associated impacts would occur
within a limited, confined area of the stocks' range. The work would
occur in the vicinity of the IBR project site, and sound from the
specified activities would be blocked by the shorelines of the river
and North Portland Harbor and the curvature of the Columbia River. The
intensity and duration of take by Level A and Level B harassment would
be minimized through use of mitigation measures described herein.
Further, the presence of pinnipeds in the area is limited and typically
transitory as animals migrate up or downriver in pursuit of prey or to
and from haulout locations, thereby reducing the potential for
prolonged exposure or behavioral disturbance. In addition, NMFS does
not anticipate that serious injury or mortality will occur as a result
of the IBRP's planned activity given the nature of the activity, even
in the absence of required mitigation.
Exposures to elevated sound levels produced during pile driving may
cause the behavioral disturbance of some individuals. Behavioral
responses of marine mammals to pile driving at the IBR project site are
expected to be mild, short term, and temporary. Effects on individuals
that are taken by Level B harassment, as enumerated in the Estimated
Take section, on the basis of reports in the literature as well as
monitoring from other similar activities at the IBRP and elsewhere,
will likely be limited to reactions such as increased swimming speeds,
increased surfacing time, or decreased foraging if such activity were
occurring (e.g., Ridgway et al., 1997; Nowacek et al., 2007; Thorson
and Reyff, 2006; Kendall and Cornick, 2015; Goldbogen et al., 2013b;
Blair et al., 2016; Wisniewska et al., 2018; Piwetz et al., 2021).
Marine mammals within the Level B harassment zones may not show any
visual cues that they
[[Page 40523]]
are disturbed by activities, or they could become alert, avoid the
area, leave the area, or display other mild responses that are not
visually observable such as exhibiting increased stress levels (e.g.,
Rolland et al., 2012; Lusseau, 2005; Bejder et al., 2006; Rako et al.,
2013; Pirotta et al., 2015; P[eacute]rez-Jorge et al., 2016). They may
also exhibit increased vocalization rates, louder vocalizations,
alterations in the spectral features of vocalizations, or a cessation
of communication signals (Hotchkin and Parks 2013).
All three marine mammal species present in the region will only be
present temporarily based on seasonal patterns or during transit
between other habitats. Thus, individuals present will be exposed to
only transient periods of noise-generating activity as they move up- or
down-river past the project site. Most likely, individual animals will
either be temporarily deterred from swimming past the construction
activities and will pass by when no pile driving is occurring, or will
swim through the area more quickly. Takes may also occur during
important foraging seasons, when anadromous fishes are migrating past
the project area and marine mammals follow. However, the IBR project
area represents a small portion of available foraging habitat and
impacts on marine mammal feeding for all species are expected to be
minimal. No marine mammal species or individuals are known or expected
to be resident in the project area, and impacts are unlikely to be more
than temporary and low-intensity.
The activities analyzed here are similar to numerous other coastal
construction activities conducted in the Columbia River (e.g., 84 FR
53689, October 8, 2019; 89 FR 64420, August 7, 2024) which have taken
place with no known long-term adverse consequences from behavioral
harassment. Any potential reactions and behavioral changes are expected
to subside quickly when the exposures cease, and therefore, no long-
term adverse consequences are expected (e.g., Graham et al., 2017).
While there are no long-term peer-reviewed studies of marine mammal
habitat use in the Columbia River, studies from other areas indicate
that most marine mammals would be expected to have responses on the
order of hours to days. The intensity of Level B harassment events will
be minimized through use of mitigation measures described herein, which
were not quantitatively factored into the take estimates. The IBRP will
use PSOs stationed strategically to increase detectability of marine
mammals during in-water construction activities, enabling a high rate
of success in implementation of shutdowns to minimize injury for most
species. Further, given the absence of any major rookeries and haulouts
within the estimated harassment zones, we assume that potential takes
by Level B harassment will have an inconsequential short-term effect on
individuals and will not result in population-level impacts.
As stated in the Mitigation section, the IBRP will implement
shutdown zones (table 18). Take by Level A harassment may be authorized
for all three marine mammal species to account for the potential that
an animal could enter and remain unobserved within the estimated Level
A harassment zone for a duration long enough to incur AUD INJ. Any take
by Level A harassment is expected to arise from, at most, a small
degree of AUD INJ because animals would need to be exposed to higher
levels and/or longer duration than are expected to occur here in order
to incur any more than a small degree of AUD INJ.
Due to the levels and durations of likely exposure, animals that
experience AUD INJ will likely only receive slight injury (i.e., minor
degradation of hearing capabilities within regions of hearing that
align most completely with the frequency range of the energy produced
by IBRP's in-water construction activities (i.e., the low-frequency
region below 2 kHz)), not severe hearing impairment or impairment in
the ranges of greatest hearing sensitivity. If hearing impairment does
occur, it is most likely that the affected animal will lose a few dBs
in its hearing sensitivity, which, in most cases, is not likely to
meaningfully affect its ability to forage and communicate with
conspecifics. There are no data to suggest that a single instance in
which an animal incurs AUD INJ (or TTS) would result in impacts to
reproduction or survival. If AUD INJ were to occur, it would be minor
and unlikely to affect more than a few individuals. Additionally, and
as noted previously, some subset of the individuals that are
behaviorally harassed could also simultaneously incur some small degree
of TTS for a short duration of time. Because of the small degree
anticipated, though, any AUD INJ or TTS potentially incurred here is
not expected to adversely impact individual fitness, let alone annual
rates of recruitment or survival for the affected species or stocks.
Repeated, sequential exposure to pile driving noise over a long
duration could result in more severe impacts to individuals that could
affect a population (via sustained or repeated disruption of important
behaviors such as feeding, resting, traveling, and socializing;
Southall et al., 2007). Alternatively, marine mammals exposed to
repetitious construction sounds may become habituated, desensitized, or
tolerant after initial exposure to these sounds (reviewed by Richardson
et al., 1995; Southall et al., 2007). However, given the relatively low
abundance and generally transitory nature of marine mammals in the
Columbia River near the project location compared to the stock sizes
(table 19), population-level impacts are not anticipated. The absence
of any pinniped haulouts or other known home-ranges in the action area
further decreases the likelihood of population-level impacts.
The IBR project is also not expected to have significant adverse
effects on any marine mammal habitats. The long-term impact on marine
mammals associated with IBR project would be a small permanent decrease
in low-quality potential habitat because of the expanded footprint of
the bridges. Installation and removal of in-water piles would be
temporary and intermittent, and the increased footprint of the
facilities would destroy only a small amount of low-quality habitat,
which currently experiences high levels of anthropogenic activity.
Impacts to the immediate substrate are anticipated, but these would be
limited to minor, temporary suspension of sediments, which could impact
water quality and visibility for a short amount of time but which would
not be expected to have any effects on individual marine mammals.
Further, there are no known biologically important areas (BIAs) near
the IBR project zone that will be impacted by the IBRP's proposed
activities.
Impacts to marine mammal prey species are also expected to be minor
and temporary and to have, at most, short-term effects on foraging of
individual marine mammals and likely no effect on the populations of
marine mammals as a whole. Overall, the area impacted by the IBR
project is very small compared to the available surrounding habitat and
does not include habitat of particular importance. The river serves as
spawning habitat for anadromous salmonids, but there are no documented
spawning sites in the vicinity of the I-5 bridges. The most likely
impact to prey would be temporary behavioral avoidance of the immediate
area. During construction activities, it is expected that some fish and
marine mammals would temporarily leave the area of disturbance, thus
impacting marine
[[Page 40524]]
mammals' foraging opportunities in a limited portion of their foraging
range. But, because of the relatively small area of the habitat that
may be affected and lack of any habitat of particular importance, the
impacts to marine mammal habitat are not expected to cause significant
or long-term negative consequences.
In summary and as described above, the following factors primarily
support our preliminary negligible impact determinations for the
affected stocks of California sea lions, Steller sea lions, and harbor
seals:
No takes by mortality or serious injury are anticipated or
authorized;
Any acoustic impacts to marine mammal habitat from pile
driving are expected to be temporary and minimal;
Take will not occur in places and/or times where take
would be more likely to accrue to impacts on reproduction or survival,
such as within habitats critical to recruitment or survival (e.g.,
rookery);
The IBR project area represents a very small portion of
the available foraging area for all potentially impacted marine mammal
species and does not contain any habitat of particular importance;
Take will only occur within the Columbia River and North
Portland Harbor, which is a limited, confined area of any given stock's
home range;
Monitoring reports from similar work have documented
little to no observable effect on individuals of the same species
impacted by the specified activities;
The required mitigation measures (i.e., soft starts, pre-
clearance monitoring, shutdown zones, bubble curtains) are expected to
be effective in reducing the effects of the specified activity by
minimizing the numbers of marine mammals exposed to injurious levels of
sound and by ensuring that any take by Level A harassment is, at most,
a small degree of AUD INJ and of a lower degree that would not impact
the fitness of any animals; and
The intensity of anticipated takes by Level B harassment
is low for all stocks consisting of, at worst, temporary modifications
in behavior, and would not be of a duration or intensity expected to
result in impacts on reproduction or survival.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under section 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the maximum number of individuals
taken in any year to the most appropriate estimation of abundance of
the relevant species or stock in our determination of whether an
authorization is limited to small numbers of marine mammals. When the
predicted maximum annual number of individuals to be taken is fewer
than one-third of the species or stock abundance, the take is
considered to be of small numbers. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
For all stocks, the number of takes proposed for authorization is
less than one-third of the best available population abundance estimate
(i.e., approximately 17.3 percent for harbor seals; approximately 10.7
percent for Steller sea lions; and approximately 1.5 percent for
California sea lions; see table 17). The maximum annual number of
animals that may be authorized to be taken from these stocks would be
considered small relative to the relevant stock's abundances even if
each estimated take occurred to a new individual. Due to the inability
to discriminate between pinniped species in the most recent available
survey data from ODOT, the number of takes proposed for authorization
likely represents smaller numbers of all three species. For all
species, PSOs will count individuals as separate unless they can be
individually identified.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency insure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of IHAs, NMFS consults
internally whenever we propose to authorize take for endangered or
threatened species.
No incidental take of ESA-listed species is proposed for
authorization or expected to result from this activity. Therefore, NMFS
has determined that formal consultation under section 7 of the ESA is
not required for this action.
Proposed Promulgation
As a result of these preliminary determinations, NMFS proposes to
promulgate regulations that allow for the authorization of take, by
Level A harassment and Level B harassment, incidental to construction
activities associated with the IBR project for a 5-year period from
September 15, 2027, through September 14, 2032, provided the previously
mentioned mitigation, monitoring, and reporting requirements are
incorporated.
Request for Information
NMFS requests interested persons to submit comments, information,
and suggestions concerning the IBRP's request and the proposed
regulations (see ADDRESSES). All comments will be reviewed and
evaluated as we prepare a final rule and make final determinations on
whether to issue the requested authorization. This proposed rule and
referenced documents provide all environmental information relating to
our proposed action for public review.
Classification
The Office of Management and Budget has determined that this
proposed rule is not significant for purposes of Executive Order 12866.
This proposed rule is not an Executive Order 14192 regulatory action
because this proposed rule is not significant under Executive Order
12866.
Pursuant to section 605(b) of the Regulatory Flexibility Act (5
U.S.C. 601 et seq.), the Chief Counsel for Regulation of the Department
of Commerce has certified to the Chief Counsel for Advocacy of the
Small Business Administration that this proposed rule, if adopted,
would not
[[Page 40525]]
have a significant economic impact on a substantial number of small
entities. The IBRP is a bi-state governmental program focused on
improving the transit corridor between Washington and Oregon. The IBRP
is the sole entity that would be subject to the requirements in the
proposed rule, and the IBRP is not a small governmental jurisdiction,
small organization, or small business, as defined by the RFA, because
it is a department of the two state governments. Because of this
certification, a regulatory flexibility analysis is not required and
none has been prepared.
This proposed rule contains a collection-of-information requirement
subject to the provisions of the Paperwork Reduction Act (PRA).
Notwithstanding any other provision of law, no person is required to
respond to nor shall a person be subject to a penalty for failure to
comply with a collection of information subject to the requirements of
the PRA unless that collection of information displays a currently
valid Office of Management and Budget (OMB) control number. These
requirements have been approved by OMB under control number 0648-0151
and include applications for regulations, subsequent LOAs, and reports.
List of Subjects
Acoustics, Administrative practice and procedure, Construction,
Marine mammals, Mitigation and monitoring requirements, Reporting
requirements, Wildlife.
Dated: August 14, 2025.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
For reasons set forth in the preamble, NMFS proposes to revise 50
CFR part 217 as follows:
PART 217--REGULATIONS GOVERNING THE TAKE OF MARINE MAMMALS
INCIDENTAL TO SPECIFIED ACTIVITIES
0
1. The authority citation for part 217 continues to read as follows:
Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.
0
2. Add Subpart O, consisting of Sec. Sec. 217.141 through 217.149, to
read as follows:
Subpart O--Taking Marine Mammals Incidental to the Interstate Bridge
Replacement Project on Interstate 5 Between Portland, Oregon and
Vancouver, WA
Sec.
217.141 Specified activity and specified geographical region.
217.142 Effective dates.
217.143 Permissible methods of taking.
217.144 Prohibitions.
217.145 Mitigation requirements.
217.146 Requirements for monitoring and reporting.
217.147 Letters of Authorization.
217.148 Modifications of Letters of Authorization.
217.149 [Reserved]
Subpart O--Taking Marine Mammals Incidental to the Interstate
Bridge Replacement Project on Interstate 5 Between Portland, Oregon
and Vancouver, WA
Sec. 217.141 Specified activity and specified geographical region.
(a) The incidental taking of marine mammals by the Interstate
Bridge Replacement Program (IBRP) may be authorized in a letter of
authorization (LOA) only if it occurs at or around the Interstate 5
bridges over the Columbia River and North Portland Harbor between
Portland, OR and Vancouver, WA incidental to the specified activities
outlined in paragraph (b) of this section. Requirements imposed on the
IBRP in this subpart must be implemented by those persons it authorizes
or funds to conduct activities on its behalf.
(b) The specified activities are construction and demolition
activities associated with the Interstate Bridge Replacement Project
between Portland, OR and Vancouver, WA.
Sec. 217.142 Effective dates.
Regulations in this subpart are effective from September 15, 2027,
until September 14, 2032.
Sec. 217.143 Permissible methods of taking.
Under a LOA issued pursuant to Sec. Sec. 216.106 of this chapter
and this subpart, the IBRP and those persons it authorizes or funds to
conduct activities on its behalf may incidentally, but not
intentionally, take marine mammals within the specified geographical
region by harassment associated with the specified activities provided
they are in compliance with all terms, conditions, and requirements of
the regulations in this subpart and the applicable LOA.
Sec. 217.144 Prohibitions.
(a) Except for the takings permitted in Sec. 217.143 and
authorized by a LOA issued under Sec. Sec. 216.106 of this chapter and
this subpart, it is unlawful for any person to do any of the following
in connection with the specified activities:
(1) Violate or fail to comply with the terms, conditions, and
requirements of this subpart or a LOA issued under this subpart;
(2) Take any marine mammal not specified in such LOA;
(3) Take any marine mammal specified in such LOA in any manner
other than as specified;
(4) Take a marine mammal specified in such LOA after NMFS
determines such taking results in more than a negligible impact on the
species or stocks of such marine mammal; or
(5) Take a marine mammal specified in such LOA after NMFS
determines such taking results in an unmitigable adverse impact on the
species or stock of such marine mammal for taking for subsistence uses.
(b) [Reserved]
Sec. 217.145 Mitigation requirements.
(a) When conducting the specified activities identified in Sec.
217.141(b), IBRP must implement the mitigation measures contained in
this section and any LOA issued under Sec. Sec. 216.106 of this
chapter and this subpart. These mitigation measures include, but are
not limited to:
(1) A copy of any issued LOA must be in the possession of the IBRP,
its designees, and work crew personnel operating under the authority of
the issued LOA;
(2) The IBRP must ensure that construction supervisors and crews,
the monitoring team and relevant IBRP staff are trained prior to the
start of all pile driving so that responsibilities, communication
procedures, monitoring protocols, and operational procedures are
clearly understood. New personnel joining during the project must be
trained prior to commencing work; and
(3) The IBRP, construction supervisors and crews, Protected Species
Observers (PSOs), and relevant IBRP staff must avoid direct physical
interaction with marine mammals during construction activity. If a
marine mammal comes within 10 m of such activity, operations must cease
and vessels must reduce speed to the minimum level required to maintain
steerage and safe working conditions, as necessary to avoid direct
physical interaction;
(4) The IBRP must employ PSOs and establish monitoring locations
pursuant to Sec. 217.146 and as described in a NMFS-approved Marine
Mammal Monitoring and Mitigation Plan;
(i) For all pile driving activities, land-based PSOs must be
stationed at the best vantage points practicable to monitor for marine
mammals and implement shutdown/delay procedures. A minimum of two
locations must be used to monitor the harassment zones specified in any
LOA issued under Sec. Sec. 216.106 of this chapter and this
[[Page 40526]]
subpart to the maximum extent possible based on positioning and daily
visibility conditions. PSOs must be able to implement shutdown or delay
procedures when applicable through communication with the equipment
operator;
(ii) If during pile driving activities, PSOs can no longer
effectively monitor the entirety of the shutdown zone (see Sec.
217.146 (a) (6), below) due to environmental conditions (e.g., fog,
rain, wind), pile driving may continue only until the current segment
of the pile is driven; no additional sections of pile or additional
piles may be driven until conditions improve such that the shutdown
zone can be effectively monitored. If the shutdown zone cannot be
monitored for more than 15 minutes, the entire zone must be cleared
again for 30 minutes prior to reinitiating pile driving;
(5) Pre-start clearance monitoring must take place from 30 minutes
prior to initiation of pile driving activity (i.e., pre-start clearance
monitoring) through 30 minutes post-completion of pile driving
activity;
(i) Pre-start clearance monitoring must be conducted during periods
of visibility sufficient for the lead PSO to determine that the
shutdown zones are clear of marine mammals;
(ii) Pile driving may only commence if, following 30 minutes of
observation, it is determined by the lead PSO that the shutdown zones
are clear of marine mammals;
(6) For all pile driving activity, the IBRP must implement shutdown
zones with radial distances as identified in a LOA issued under
Sec. Sec. 216.106 of this chapter and this subpart;
(i) If a marine mammal is observed entering or within the shutdown
zone, all pile driving activities, including soft starts, at that
location must be halted. If pile driving is halted or delayed due to
the presence of a marine mammal, the activity may not commence or
resume until either the animal has voluntarily left and has been
visually confirmed beyond the shutdown zone or 15 minutes have passed
without re-detection of the animal;
(ii) In the event of a delay or shutdown of activity resulting from
marine mammals in the shutdown zone, animal behavior must be monitored
and documented;
(iii) If work ceases for more than 30 minutes, the shutdown zones
must be cleared again for 30 minutes prior to reinitiating pile
driving. A determination that the shutdown zone is clear must be made
by the lead PSO during a period of good visibility;
(v) For in-water construction activities other than pile driving
(e.g., drilling; barge positioning; use of barge-mounted excavators;
dredging), if a marine mammal comes within 10 m, IBRP must cease
operations and reduce vessel speed to the minimum level required to
maintain steerage and safe working conditions.
(7) The IBRP must use soft start techniques when impact pile
driving. Soft start requires the IBRP to conduct three sets of strikes
(three strikes per set) at reduced hammer energy with a 30-second
waiting period between each set. A soft start must be implemented at
the start of each day's impact pile driving and at any time following
cessation of impact pile driving for a period of 30 minutes or longer;
(8) The IBRP must use bubble curtains for impact pile driving in
waters deeper than 0.67 m, except when necessary for testing of bubble
curtain effectiveness during hydroacoustic monitoring. The bubble
curtain must be operated to achieve optimal performance. At a minimum,
the bubble curtain must comply with the following:
(i) The bubble curtain must distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column;
(ii) The lowest bubble ring must be in contact with the mudline
and/or rock bottom for the full circumference of the ring, and the
weights attached to the bottom ring shall ensure 100 percent mudline
and/or rock bottom contact. No parts of the ring or other objects shall
prevent full mudline and/or rock bottom contact;
(iii) Air flow to the bubblers must be balanced around the
circumference of the pile;
(9) Pile driving activity must be halted upon observation of a
species entering or within the harassment zone for either a species for
which incidental take is not authorized or a species for which
incidental take has been authorized but the authorized number of takes
has been met;
(b) [Reserved]
Sec. 217.146 Requirements for monitoring and reporting.
(a) The IBRP must submit a marine mammal monitoring plan to NMFS
for approval at least 90 days before the start of construction and
abide by the plan, if approved.
(b) The IBRP must submit a hydroacoustic monitoring plan to NMFS
for approval at least 60 days before the start of impact pile driving,
and abide by the plan, if approved.
(c) Monitoring must be conducted by qualified, NMFS-approved PSOs,
in accordance with the following conditions:
(1) PSOs must be independent of the activity contractor (e.g.,
employed by a subcontractor) and have no other assigned tasks during
monitoring duties;
(2) PSOs must be approved by NMFS prior to beginning work on the
specified activities;
(3) PSOs must be trained in marine mammal identification and
behavior;
(i) A designated project lead PSO must be on site when more than
two PSOs are on duty. The project lead PSO must have prior experience
performing the duties of a PSO during in-water construction activities
pursuant to a NMFS-issued ITA or letter of concurrence;
(ii) Other PSOs may substitute other relevant experience, education
(degree in biological science or related field), or training for prior
experience performing the duties of a PSO during construction activity
pursuant to a NMFS-issued incidental take authorization;
(d) The IBRP must submit a draft annual summary monitoring report
on all marine mammal monitoring conducted during each construction
season which includes final electronic data sheets in a searchable
format within 90 calendar days after the completion of each
construction season or 60 days prior to a requested date of issuance of
any future incidental take authorization for projects at the same
location, whichever comes first. A draft comprehensive 5-year summary
report must also be submitted to NMFS within 90 days of the end of year
5 of the project. The reports must detail the monitoring protocol and
summarize the data recorded during monitoring. If no comments are
received from NMFS within 30 days of receipt of the draft report, the
report may be considered final. If comments are received, a final
report addressing NMFS comments must be submitted within 30 days after
receipt. At a minimum, the reports must contain:
(1) Dates and times (begin and end) of all marine mammal
monitoring;
(2) Construction activities occurring during each daily observation
period, including how many and what type of piles were driven or
removed, by what method (i.e., impact or vibratory), the total duration
of driving time for each pile (vibratory driving), and number of
strikes for each pile (impact driving);
(3) Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), Beaufort sea state, and any other relevant weather
conditions including cloud cover, fog, sun glare, and overall
[[Page 40527]]
visibility to the horizon, and estimated observable distance (if less
than the harassment zone distance);
(4) Upon observation of a marine mammal, the following information
must be collected:
(i) Name of the PSO who sighted the animal, observer location, and
activity at time of sighting;
(ii) Time of sighting;
(iii) Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
(iv) Distances and bearings of each marine mammal observed in
relation to the pile being driven for each sighting (if pile driving
was occurring at time of sighting);
(v) Estimated number of animals (min/max/best);
(vi) Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
(vii) Animal's closest point of approach and estimated time spent
within the harassment zone;
(viii) Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses to the activity (e.g., no response
or changes in behavioral state such as ceasing feeding, changing
direction, flushing, or breaching);
(ix) Detailed information about any implementation of any
mitigation (e.g., shutdowns and delays), a description of specific
actions that ensued, and resulting changes in the behavior of the
animal, if any; and
(x) All PSO data in an electronic format that can be queried such
as a spreadsheet or database (i.e., digital images of data sheets are
not sufficient).
(e) Acoustic monitoring report(s) must be submitted on the same
schedule as visual monitoring reports (i.e., within 90 days following
the completion of construction). The acoustic monitoring report must
contain the informational elements described in the acoustic monitoring
plan and, at minimum, must include:
(i) Hydrophone equipment and methods: (1) recording device,
sampling rate, calibration details, distance (m) from the pile where
recordings were made; and (2) the depth of water and recording
device(s);
(ii) Location, identifier, orientation (e.g., vertical, battered),
material, and geometry (shape, diameter, thickness, length) of pile
being driven, substrate type, method of driving during recordings
(e.g., hammer model and energy), and total pile driving duration;
(iii) Whether a sound attenuation device is used and, if so, a
detailed description of the device used, its distance from the pile and
hydrophone, and the duration of its use per pile;
(iv) For impact pile driving: (1) number of strikes per day and per
pile and strike rate; (2) depth of substrate to penetrate; (3)
decidecade (one-third octave) band spectra in tabular and figure
formats computed on a per-pulse basis, including the arithmetic mean or
median for all computed spectra; (4) pulse duration and median, mean,
maximum, minimum, and number of samples (where relevant) of the
following sound level metrics: RMS SPL; SEL24; peak (PK)
SPL; and SELss; and
(v) For any monitored vibratory pile driving: (1) duration of
driving for each pile; (2) depth of substrate to penetrate; (3)
decidecade (one-third octave) band spectra in tabular and figure
formats, including the arithmetic mean or median for all computed
spectra; (4) duration and median, mean, maximum, minimum, and number of
samples (where relevant) of the following level metrics: RMS SPL;
SEL24; peak (PK) SPL; and SELss.
(f) In the event that personnel involved in the construction
activities discover an injured or dead marine mammal, the IBRP must
report the incident to NMFS Office of Protected Resources (OPR) and to
the West Coast Regional Stranding Coordinator no later than 24 hours
after the initial observation. If the death or injury was caused by the
specified activity, the IBRP must immediately cease the specified
activities described in Sec. 217.141(b) until NMFS OPR is able to
review the circumstances of the incident. The IBRP must not resume
their activities until notified by NMFS. The report must include the
following information:
(1) Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
(2) Species identification (if known) or description of the
animal(s) involved;
(3) Condition of the animal(s) (including carcass condition if the
animal is dead);
(4) Observed behaviors of the animal(s), if alive;
(5) If available, photographs or video footage of the animal(s);
and
(6) General circumstances under which the animal was discovered.
Sec. 217.147 Letters of Authorization.
(a) To incidentally take marine mammals pursuant to these
regulations, the IBRP must apply for and obtain an LOA.
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the effective dates of this subpart.
(c) If an LOA expires prior to the end of the effective dates of
this subpart, the IBRP may apply for and obtain a renewal of the LOA.
(d) In the event of projected changes to the activity or to
mitigation and monitoring measures required by an LOA, the IBRP must
apply for and obtain a modification of the LOA as described in Sec.
217.148.
(e) The LOA must set forth the following information:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, its habitat, and on the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
(f) Issuance of the LOA must be based on a determination that the
level of taking will be consistent with the findings made for the total
taking allowable under this subpart.
(g) Notice of issuance or denial of an LOA must be published in the
Federal Register within 30 days of a determination.
Sec. 217.148 Modifications of Letters of Authorization.
(a) A LOA issued under Sec. Sec. 216.106 of this chapter and
217.147 for the specified activities may be modified upon request by
the IBRP, provided that:
(1) The specified activity and mitigation, monitoring, and
reporting measures, as well as the anticipated impacts, are the same as
those described and analyzed for this subpart; and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOA were implemented.
(b) For LOA modification by the IBRP that includes changes to the
specified activity or the mitigation, monitoring, or reporting measures
that do not change the findings made for the regulations in this
subpart or result in no more than a minor change in the total estimated
number of takes (or distribution by species or years), NMFS may publish
a notice of proposed LOA in the Federal Register, including the
associated analysis of the change and solicit public comment before
issuing the LOA.
(c) A LOA issued under Sec. Sec. 216.106 of this chapter and
217.147 for the specified activity may be modified by
[[Page 40528]]
NMFS under the following circumstances:
(1) NMFS may modify the existing mitigation, monitoring, or
reporting measures, after consulting with the IBRP regarding the
practicability of the modifications, if doing so creates a reasonable
likelihood of more effectively accomplishing the goals of the
mitigation and monitoring measures;
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in an LOA
include, but are not limited to:
(A) Results from the IBRP's monitoring;
(B) Results from other marine mammal and/or sound research or
studies; and
(C) Any information that reveals marine mammals may have been taken
in a manner, extent or number not authorized by this subpart or
subsequent LOAs; and
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
shall publish a notice of proposed LOA in the Federal Register and
solicit public comment;
(2) If NMFS determines that an emergency exists that poses a
significant risk to the well-being of the species or stocks of marine
mammals specified in a LOA issued pursuant to Sec. Sec. 216.106 of
this chapter and 217.147, a LOA may be modified without prior notice or
opportunity for public comment. Notification will be published in the
Federal Register within 30 days of the action.
Sec. 217.149 [Reserved]
[FR Doc. 2025-15775 Filed 8-18-25; 8:45 am]
BILLING CODE 3510-22-P