Rule2025-08231
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Lower Columbia River Dredged Material Management Plan, Oregon and Washington
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
May 12, 2025
Effective
November 1, 2027
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS, upon request from the U.S. Army Corps of Engineers (USACE), issues regulations to govern the unintentional taking of marine mammals incidental to implementation of the Lower Columbia River Dredged Material Management Plan in Oregon and Washington over 5 years (2027-2032). These regulations, which allow for the issuance of a Letter of Authorization (LOA) for the incidental take of marine mammals during the specified activities and timeframes, prescribe the permissible methods of taking and effecting the least practicable adverse impact on marine mammal species or stocks and their habitat, as well as monitoring and reporting requirements.
Full Text
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[Federal Register Volume 90, Number 90 (Monday, May 12, 2025)]
[Rules and Regulations]
[Pages 20110-20127]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-08231]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 250505-0077]
RIN 0648-BN12
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Lower Columbia River Dredged
Material Management Plan, Oregon and Washington
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Final rule.
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SUMMARY: NMFS, upon request from the U.S. Army Corps of Engineers
(USACE), issues regulations to govern the unintentional taking of
marine mammals incidental to implementation of the Lower Columbia River
Dredged Material Management Plan in Oregon and Washington over 5 years
(2027-2032). These regulations, which allow for the issuance of a
Letter of Authorization (LOA) for the incidental take of marine mammals
during the specified activities and timeframes, prescribe the
permissible methods of taking and effecting the least practicable
adverse impact on marine mammal species or stocks and their habitat, as
well as monitoring and reporting requirements.
DATES: This rule is effective from November 1, 2027 through February
29, 2032.
ADDRESSES: A copy of the USACE's application and any supporting
documents, as well as a list of the references cited in this document,
may be obtained online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-lower-columbia-river-dredged-material">https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-lower-columbia-river-dredged-material</a>.
In case of problems accessing these documents, please call the
contact listed below.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Purpose and Need for Regulatory Action
This rule establishes a framework under the authority of the Marine
Mammal Protection Act (MMPA) (16 U.S.C. 1361 et seq.) to allow for the
authorization of take of marine mammals incidental to the USACE's
construction activities related to the Lower Columbia River (LCR)
Dredged Materials Management Plan (DMMP).
We received an application from the USACE requesting 5-year
regulations and authorization to take multiple species of marine
mammals. Take is anticipated to occur incidental to impact and
vibratory pile driving, by Level A and Level B harassment only. Please
see Background below for definitions of harassment.
Legal Authority for the Action
Section 101(a)(5)(A)(i) of the MMPA (16 U.S.C. 1371(a)(5)(A)(i))
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
[[Page 20111]]
agency ``finds that the total of such taking during each . . . period
concerned will have a negligible impact on such species or stock and
will not have an unmitigable adverse impact on the availability of such
species or stock for taking for subsistence uses'' and issues
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 stock and their habitat''
as well as monitoring and reporting requirements. As such, this
provision of the MMPA and the implementing regulations at 50 CFR
216.105 and 216.106 provides the legal basis for issuing this rule
containing 5-year regulations and for any subsequent LOAs.
Summary of Major Provisions
The major provisions of this final rule include:
<bullet> Monitoring of the construction areas to detect the
presence of marine mammals before beginning construction activities;
<bullet> Shutdown of construction activities under certain
circumstances to avoid injury of marine mammals;
<bullet> 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; and
<bullet> Use of bubble curtains to attenuate sound levels when
impact pile driving.
Legal Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct 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 incidental take authorization (ITA) 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 mitigation,
monitoring and reporting of the takings are set forth (section
101(5)(A)(i)(II)(aa)).
Summary of Request
On October 18, 2023, NMFS received a request (Application) from the
USACE for authorization to take marine mammals incidental to
construction activities associated with the LCR DMMP in Oregon and
Washington. After the applicant responded to our questions and
redrafted the Application, we determined the Application was adequate
and complete on April 25, 2024. On May 14, 2024, we published a notice
of receipt of the USACE Application in the Federal Register, requesting
comments and information related to the request for 30 days (89 FR
41941). We received no public comments during the public comment
period.
On November 13, 2024, NMFS published a notice of proposed
rulemaking and request for public comments in the Federal Register (89
FR 89543). All comments were considered in development of this final
rule (see Comments and Responses). The USACE's request is for the take
of harbor seal (Phoca vitulina), Steller sea lion (Eumetopias jubatus),
and California sea lion (Zalophus californianus) by Level B harassment
and, for harbor seal only, by Level A harassment. The regulations are
valid for 5 years (2027-2032).
Description of the Activity
The USACE has developed a draft DMMP to support continued operation
and maintenance of the LCR Federal Navigation Channel (FNC) for the
next 20 years. The full draft DMMP includes planned dredging and
placement operations between river miles (RM) 3 (4.8 kilometers (km))
and 105.5 (169.8 km). However, the scope of this request for a LOA is
limited to potential pile driving that would be associated with any new
steel and timber piles installed between RM 23 and 36. Work on
additional reaches of the LCR will likely occur in subsequent years.
The USACE is anticipating up to 141 days of in-water work between
November 2027 and February 2032 and is planning to install 1,039 steel
piles and 1,029 timber piles by vibratory and impact driving over the
5-year LOA period for a total of 2,068 piles. No concurrent driving of
piles is planned.
A detailed description of the planned construction project is
provided in the Federal Register notice for the proposed rule (89 FR
89543). Since that time, no changes have been made to the planned
activities. Therefore, a detailed description is not provided here.
Comments and Responses
NMFS' notice of proposed rulemaking was published in the Federal
Register on November 13, 2024 (89 FR 89543). That proposed rule
described, in detail, the USACE's activities, the marine mammal species
that may be affected by the activities, and the anticipated effects on
marine mammals. In that proposed rule, we requested public input on the
request for authorization described therein, our analyses, the proposed
authorization, and any other aspect of the notice of proposed
rulemaking, and requested that interested persons submit relevant
information, suggestions, and comments.
During the 30-day public comment period, NMFS received four
substantive comment submissions from members of the public and from the
Center for Regulatory Freedom. NMFS' responses to the comments are
provided below, and all comments are available online at: <a href="https://www.regulations.gov/document/NOAA-NMFS-2024-0123-0001/comment">https://www.regulations.gov/document/NOAA-NMFS-2024-0123-0001/comment</a>.
Comment 1: One commenter inquired if plans for the dredging project
extend beyond the allotted 5-year LOA effective period of 2027-2032.
The commenter also asked if the USACE would reapply for authorized take
if work were undertaken beyond the end of the effective date of this
LOA (February 29, 2032).
Response: The USACE has stated that it plans additional
construction activities at other locations during the 2033/2034 and
2034/2035 work windows along the LCR that were not analyzed and are not
covered under this rulemaking and LOA. The USACE would need to submit
an application for an ITA in the form of an IHA or LOA for any work
that could result in incidental take of marine mammals occurring after
the end of the LOA's effective date (February 29, 2032). Additionally,
any activities planned to occur under this LOA that were not completed
would need to be included in subsequent incidental take authorizations
requested by the USACE.
Comment 2: A commenter asked how NMFS would respond in a situation
in which take of marine mammals is higher than predicted.
Response: In the event that the USACE exceeds the authorized or
predicted take levels, any further take
[[Page 20112]]
would be unauthorized and therefore, prohibited under the MMPA. The
USACE would require authorization for additional activities that could
result in incidental take. Providing such authorization would require
NMFS to reanalyze its small numbers and negligible impact
determinations. Under certain conditions, including monitoring data
showing rates of take in excess of expectations, the LOA could
potentially be modified to increase the number of authorized takes and/
or adjust mitigation measures. See Adaptive Management section and 50
CFR 217.77 (addressing LOA modification requests).
Comment 3: A member of the public asked if alternate locations are
available to install the specified infrastructure.
Response: The LCR DMMP is a coordinated, long-term plan for
managing dredged material generated by the continued operations and
maintenance (O&M) of the LCR Federal Navigation Channel (FNC) for a
minimum of 20 years to continue to provide a 43-foot-deep and 600-foot-
wide channel. Existing pile dike structures reduce dredging needs and
confine dredged material. The purpose of repairs or replacement is to
restore full function of a pile dike system in the context of existing
(present day) channel configuration, hydrologic, and environmental
river conditions. Functional pile dikes are critical for continued
navigation channel maintenance and have been placed in specific
locations to maximize operational conditions. Specifically, these
defined locations are the best solution for providing sufficient
dredged material placement capacity while also providing environmental,
economic, and social benefits by sustaining the Columbia River's
sediment budget and morphology, developing fish and wildlife habitat,
and providing opportunities for recreation and commercial uses to
include fishing, nourishment, aesthetics, and bird watching. Removal
and relocation of these pile dikes would likely negatively impact one
or more of the described benefits.
Comment 4: A member of the public asked to see alternate plans in
the case of undue harm to local wildlife populations at the proposed
pile-driving sites.
Response: NMFS did not develop alternatives as part of the analysis
of the Application because the agency determined the action fell within
Categorical Exclusion B4 of the Companion Manual for NAO 216-6A
(available at <a href="https://www.noaa.gov/sites/default/files/2021-10/NOAA-NAO-216-6A-Companion-Manual-03012018%20%281%29.pdf">https://www.noaa.gov/sites/default/files/2021-10/NOAA-NAO-216-6A-Companion-Manual-03012018%20%281%29.pdf</a>), and therefore a
National Environmental Policy Act (NEPA) analysis (which could include
an alternatives analysis) is unnecessary. Any undue harm would likely
be exceedance of authorized take numbers or take in excess of expected
levels. In such situations, the LOA could be modified to accommodate
the predicted increase in take and/or mitigation measures could be
revised if such modifications would have a reasonable likelihood of
reducing adverse effects to marine mammals and if the measures are
practicable. See Adaptive Management section and 50 CFR 217.77(c)
(addressing LOA modification requests).
Comment 5: One commenter inquired about the potential impacts to
affected animals when they are physically moved to areas away from the
project location.
Response: The USACE did not request and NMFS has not authorized the
intentional relocation of marine mammals away from the project area.
The USACE requested and NMFS has authorized the take of marine mammals
incidental to DMMP project activities. Take would occur by harassment
only (defined in Estimated Take of Marine Mammals section), incidental
to impact and vibratory pile driving. Relocation of marine mammals
would constitute an intentional act, i.e., not an incidental taking,
and, therefore, cannot be addressed through sections 101(a)(5)(A) or
(D) of the MMPA. Note that this action is not related to the Pinniped
Removal Program at Bonneville Dam (<a href="https://www.fisheries.noaa.gov/west-coast/marine-mammal-protection/marine-mammal-protection-act-section-120-pinniped-removal">https://www.fisheries.noaa.gov/west-coast/marine-mammal-protection/marine-mammal-protection-act-section-120-pinniped-removal</a>).
Comment 6: A member of the public who supported the issuance of the
LOA also strongly encouraged NMFS to implement comprehensive mitigation
measures designed to protect vulnerable species. Recommended measures
included abiding by season restrictions, utilizing real-time monitoring
systems, employing advanced noise reduction techniques, and applying
adaptive management strategies. They also stressed the importance of
transparency in monitoring and reporting efforts.
Response: All of the mitigation measures described by the commenter
have been included in the regulations and the LOA. See the Mitigation
section for information on noise reduction techniques (i.e., bubble
curtains, soft-start). Information on seasonal restrictions, real-time
monitoring (i.e., use of protected species observers (PSOs)) and
reporting may be found in the Monitoring and Reporting section.
Transparency is achieved by requiring monitoring during all activities
that could result in the harassment of marine mammals and posting
monitoring reports to our website for the public to view after they
have been submitted and then reviewed and approved by NMFS. (<a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>). Adaptive management options are also
included in the regulations with additional information located in the
Adaptive Management section.
Comment 7: The Center for Regulatory Freedom (CRF) indicated
support for the authorization of incidental take associated with the
dredging activities at issue. However, CRF recommended withdrawal of
the proposed rule and a ``fundamental reform of incidental takings
under the MMPA and ESA,'' stating that transparency, consistency, and
fairness in decision-making should be prioritized (and suggesting that
these are currently lacking). The CRF wrote that Federal agencies
tasked with enforcing the MMPA and ESA must establish clear, science-
based standards for evaluating environmental impacts.
Response: NMFS appreciates the support for the authorization of
incidental take of marine mammals associated with the project. The
comment does not provide analysis or information specific to the impact
of this project on marine mammals. The commenters' concerns about the
overall framework of the MMPA and ESA incidental take regulations are
outside the scope of this individual authorization and rulemaking.
Changes From the Proposed Rule to Final Rule
On May 3, 2024, NMFS published (89 FR 36762) and solicited public
comment on its draft updated Technical Guidance (<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>), which includes updated thresholds and
weighting functions to inform auditory injury estimates, and is
intended to replace the 2018 Technical Guidance (NMFS 2018). The 2024
Technical Guidance was finalized on October 24, 2024 (89 FR 84872). The
Federal Register notice for the proposed rule (89 FR 89543) for this
regulation included a basic comparative analysis of the 2018 and 2024
Technical Guidance document since at that time it was unclear when the
2024 Technical Guidance would be finalized. The revised guidance
results in changes to the Level A harassment and shutdown zones (see
Estimated Take and
[[Page 20113]]
Mitigation), which are discussed below. The updated analysis based on
the 2024 Technical Guidance did not change the take numbers authorized
through this rule.
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) (see <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website at: <a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>.
Table 1 lists all species or stocks for which take is expected and
authorized for this activity and summarizes information related to the
population or stock, including regulatory status under the MMPA and the
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 authorized here, PBR and annual serious
injury and mortality 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 1 are
the most recent available at the time of publication (including from
the 2023 SARs) and are available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 1--Marine Mammal Species \1\ Likely Impacted by the Specified Activities
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI\4\
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Order Carnivora--Pinnipedia
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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 \5\ (N/A, 2,178 93.2
36,308, 2022).
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... OR/WA Coastal.......... -, -, N 24,731 \6\ (1999)..... UND 10.6
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
at: <a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies</a>.
\2\ 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.
\3\ NMFS marine mammal SARs online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>.
CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\4\ These values, found in NMFS's 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. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only.
\6\ There is no current estimate of abundance available for this stock. Value presented is the most recent available and based on 1999 data.
A detailed description of the species likely to be affected by the
USACE's construction project, including brief introductions to the
species and relevant stocks as well as available information regarding
population trends and threats, and information regarding local
occurrence, were provided in the Federal Register notice for the
proposed rule (89 FR 89543, November 13, 2024); since that time, we are
not aware of any changes in the status of these species and stocks;
therefore, detailed descriptions are not provided here. Please refer to
that Federal Register notice for these descriptions. Please also refer
to NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) for
generalized species information.
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.). Subsequently, NMFS (2018, 2024)
described generalized hearing ranges for these marine mammal hearing
groups. Generalized hearing ranges were chosen based on the
approximately 65 decibel (dB) threshold from the normalized composite
audiograms, with the exception for lower limits for low-frequency
cetaceans where the lower bound was deemed to be biologically
implausible and the lower bound from Southall et al. (2007) retained.
[[Page 20114]]
As noted in Changes From the Proposed Rule to Final Rule, we
previously considered both the 2018 and 2024 Technical Guidance in our
effects and estimated take analysis. However for the final rule we are
only including information relevant to the 2024 Technical Guidance.
Marine mammal hearing groups and their associated hearing ranges
from NMFS (2024) are provided in table 2. In the Updated Technical
Guidance, mid-frequency cetaceans have been re-classified as high-
frequency cetaceans, and high-frequency cetaceans have been updated to
very-high-frequency (VHF) cetaceans. Additionally, the Updated
Technical Guidance includes in-air data for phocid (PA) and otariid
(OA) pinnipeds.
Table 2--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. 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.
Effects of Specified Activities on Marine Mammals and Their Habitat
The effects of underwater noise from the USACE's construction
activities have the potential to result in behavioral harassment of
marine mammals in the vicinity of the project area. The proposed rule
(89 FR 89543) included a discussion of the effects of anthropogenic
noise on marine mammals and the potential effects of underwater noise
from the USACE's construction on marine mammals and their habitat. That
information and analysis is referenced in this final rule and is not
repeated here.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
that may be authorized, which will inform both NMFS' consideration of
whether the activities will take ``small numbers'' of marine mammals
and the negligible impact determinations.
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) (16 U.S.C. 1362(18)(A)(i)-
(ii)).
For acoustic impacts, generally speaking, we estimate take by
considering (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment, (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 take estimates.
Authorized takes would primarily be by Level B harassment, as use
of the acoustic source (i.e., pile driving) has the potential to result
in disruption of behavioral patterns for individual marine mammals.
There is also some potential for auditory injury (Level A harassment)
to result, primarily for phocids because predicted auditory injury
zones are larger than for otariids. Auditory injury is unlikely to
occur for otariids. The required 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 authorized for this activity. We describe below how the
authorized take numbers have been estimated.
Acoustic Thresholds
NMFS uses acoustic thresholds to 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 permanent threshold shift (PTS), 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 levels'' (89 FR at 89550) (i.e.
hearing loss) of some degree (equated to Level A harassment).
Level B Harassment--Though significantly driven by received level
(the level of sound at a specified distance of interest (i.e., at the
animal or receiver)), 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
[[Page 20115]]
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 sources of noise (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.
Level B harassment could also take place due to temporary threshold
shift (TTS), ``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'' (89 FR
at 89552) (i.e., temporary hearing loss). Generally speaking, Level B
harassment take estimates based on behavioral harassment thresholds are
expected to include any likely takes by TTS as, in most cases, takes
from TTS are likely at shorter distances from the source 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 (e.g.,
conspecific communication, predators, prey) may result in changes in
behavior patterns that would not otherwise occur.
The USACE's planned activity includes the use of continuous
(vibratory pile driving) and impulsive (impact pile driving) sources,
and therefore NMFS will use the RMS SPL thresholds of 120 and 160 dB re
1 [mu]Pa to determine whether marine mammals are experiencing Level B
harassment.
Level A Harassment--NMFS' 2024 Updated Technical Guidance (NMFS,
2024) identifies dual criteria to assess auditory injury (Level A
harassment) to five different marine mammal groups (based on hearing
sensitivity) as a result of exposure to noise from two different types
of sources (impulsive or non-impulsive). These thresholds are provided
in table 3 below. The references, analysis, and methodology used in the
development of the thresholds are described in NMFS' 2018 Technical
Guidance and NMFS' 2024 Updated Technical Guidance, both of which may
be accessed at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
The USACE's planned activity includes the use of impulsive (impact
pile driving) and non-impulsive (vibratory driving) sources.
Table 3--NMFS' 2024 Thresholds Identifying the Onset of Auditory Injury
[AUD INJ]
----------------------------------------------------------------------------------------------------------------
AUD INJ acoustic thresholds * (received level)
Hearing group -------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
UNDERWATER:
Low-Frequency (LF) Cetaceans...... Cell 1: L0-pk,flat: 222 Cell 2: LE,LF,24h: 197 dB.
dB; LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans..... Cell 3: L0-pk,flat: 230 Cell 4: LE,p,HF,24h: 201 dB.
dB; LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cell 5: L0-pk,flat: 202 Cell 6: LE,VHF,24h: 181 dB.
Cetaceans. dB; LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater) Cell 7: L0-pk.flat: 223 Cell 8: LE,PW,24h: 195 dB.
dB; LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) Cell 9: L0-pk,flat: 230 Cell 10: LE,OW,24h: 199 dB.
(Underwater). dB; LE,OW,24h: 185 dB.
IN-AIR:
Phocid Pinnipeds (PA) (In-Air).... Cell 11: L0-pk.flat: 162 Cell 12: LE,PA,24h: 154 dB.
dB; LE,PA,24h: 140 dB.
Otariid Pinnipeds (OA) (In-Air)... Cell 13: L0-pk,flat: 177 Cell 14: LE,OA,24h: 177 dB.
dB; LE,OA,24h: 163 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for NMFS' 2018 Technical Guidance. Hence, the
subscript ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted
within the generalized hearing range. The subscript associated with cumulative sound exposure level thresholds
indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW
pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level
thresholds 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 acoustic
thresholds will be exceeded.
Ensonified Area
This section describes the operational and environmental parameters
of the activity that are used in estimating the area ensonified (or
sound field) above the acoustic thresholds, including source levels and
transmission loss (TL) coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the planned 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
LCR, including intersecting land masses that will reduce the overall
area of potential impact. Additionally, vessel traffic in the LCR
during construction may contribute to elevated background noise levels,
which may mask sounds produced by the project.
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 Log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),
where
TL = transmission loss in dB;
B = transmission loss coefficient; for practical spreading equals
15;
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile; and,
R<INF>2</INF> = 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
[[Page 20116]]
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 (20 x
log<INF>10</INF>[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 (10 x
log<INF>10</INF>[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 4). Generally, we choose source levels from similar pile types
from locations (e.g., geology, bathymetry) similar to the project.
Table 4--Proxy Sound Source Levels for Pile Sizes and Driving Methods
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Pile type Sound pressure level (single strike)
----------------------------------------------------------------------------------------------------------------
24-in Steel Pipe \1\ Vibratory ......................... 159 dBRMS................
(unattenuated).
24-in Steel Pipe \1\ \3\ Impact 198 dBPEAK............... 185 dBRMS................ 171 dBSEL.
(attenuated).
12-in Timber \2\ Vibratory ......................... 162 dBRMS................
(unattenuated).
12-in Timber \2\ \3\ Impact 175 dBPEAK............... 165 dBRMS................ 155 dBSEL.
(attenuated).
----------------------------------------------------------------------------------------------------------------
\1\ Reference levels based on the Sand Island Test Piles project in the Columbia River (Robert Miner Dynamic
Testing 2021). While the original study tested various pile tips for driving through existing enrockment, the
DMMP will not use pile tips so we referenced sound levels solely for piles excluding tips during vibratory
driving. For impact driving, all piles in the Sand Island study included tips so we used the average SPLs
across all piles as a conservative estimate.
\2\ All timber pile assumptions are based on Caltrans (2020).
\3\ We assume bubble curtains will be employed for all piles installed with an impact hammer under this LOA,
thus, SPLs in this table reflect reference noise estimates reduced by 5 dB.
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 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, the optional User
Spreadsheet tool offers the best way to estimate isopleth distances
when more sophisticated modeling methods are not available or
practical. For stationary sources such as 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 PTS. Inputs used in the optional User
Spreadsheet tool, and the resulting estimated isopleths, are reported
in table 5 below. The calculated Level A and Level B harassment
isopleths are shown in table 6.
Table 5--NMFS User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
Weighting
Spreadsheet tab factor Number of Duration to Number of
Pile size and type used adjustment piles per day drive a single strikes per
(kHz) pile (min) pile
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving and removal
----------------------------------------------------------------------------------------------------------------
24-in steel pile (Vibratory).. A.1) Vibratory 2.5 20 25 NA
pile driving.
12-in Timber (Vibratory)...... A.1) Vibratory 2.5 20 25 NA
pile driving.
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile (Impact E.1) Impact pile 2 20 NA 45
attenuated). driving.
12-in Timber (Impact E.1) Impact pile 2 20 NA 45
attenuated). driving.
----------------------------------------------------------------------------------------------------------------
Table 6--Calculated Distance of Level A (Based on NMFS' 2024 Updated Technical Guidance) and Level B Harassment
by Pile Type and Pile Driving Method
----------------------------------------------------------------------------------------------------------------
Level A harassment (m)
Pile size and type -------------------------------- Level B
Phocid Otariid harassment (m)
----------------------------------------------------------------------------------------------------------------
Vibratory pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile................................................ 35.9 12.1 3,981.1
[[Page 20117]]
12-in timber pile............................................... 56.9 19.1 6,309.6
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile................................................ 130.6 48.7 464.2
12-in timber pile............................................... 11.2 4.2 21.5
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density and/or other relevant information
which will inform the take calculations and describe how the
information provided is synthesized to produce a quantitative estimate
of the take that is reasonably likely to occur and may be authorized.
The USACE referenced data provided by the Oregon Department of Fish and
Wildlife (ODFW) and the Washington Department of Fish and Wildlife
(WDFW) to support assumptions regarding marine mammal occurrence in the
project area. The ODFW conducts periodic counts of pinnipeds at haul
out sites along the Oregon coast and in the LCR. The WDFW has collected
recent anecdotal evidence of pinniped abundance at haul out sites in
the LCR near the confluence of the Cowlitz River at RM 67.5 (108.6 km).
While the confluence of the two rivers is located approximately 31.5
river miles (50.7 km) upstream from the project area, it is the closest
site that features data on pinniped activity. The USACE used the
proximal count estimates from ODFW and WDFW to estimate the number of
harbor seals, Steller sea lions, and California sea lions that could
transit or occupy the project area during planned pile driving in
winter (i.e., November through February). For sea lions, the USACE
estimated the maximum number of animals likely to be encountered in a
single day based on the maximum number of animals detected at haul out
sites within 5 mi. (3.1 km) of planned pile driving, as well as the
closest haul out sites upstream or downstream. For harbor seals, the
USACE estimated the harbor seal density using the approximate span of
river where they have been observed at haul out sites.
Harbor Seal
The most recent harbor seal aerial surveys were conducted by ODFW
during the 2021 summer pupping season. The average, maximum daily count
of harbor seals counted across all haulout sites in the project
vicinity in May and June was 837 (pups and non-pups combined) (USACE,
2024). After applying the Huber et al. (2001) correction factor of
1.53, used to account for likely imperfect detection during surveys,
the adjusted number of harbor seals that may have been present during
the 2021 surveys was 1,281 individuals. However, that estimate is not
necessarily representative of the number of harbor seals that may be
present in winter.
Jeffries et al. (1984) synthesized survey data collected by the
state of Washington to document pinniped abundance and distribution in
the LCR between 1980 and 1983. Table 7 summarizes the harbor seal count
by month detected over that roughly 3-year study period (Jeffries et
al., 1984). The USACE used this data to calculate the average, maximum
total count observed across all haulout sites in the project vicinity
to estimate the proportion of animals present from November through
February relative to counts observed from May to June. The average
harbor seal count observed between November and February was
approximately 618 animals, whereas the average count for May and June
was roughly 464. The count of harbor seals in winter was 1.33 times the
number counted in May and June. To account for this seasonality, the
most recent estimate of 1,281 harbor seals in the project vicinity
during the pupping season, based on ODFW counts, could equate to a
maximum of 1,706 harbor seals in the project vicinity each day in
winter. While the USACE and NMFS acknowledge that the seasonal
correction factor is based on data that is over 40 years old, all
recent surveys have focused solely on the summer pupping season and
there is no winter data corresponding to those counts. Therefore, the
USACE, with NMFS' concurrence, relied on available data from a historic
study that included counts for multiple seasons in the same year.
The USACE assumed the maximum winter abundance of 1,706 individuals
and an even distribution of animals throughout the span of river
between the river mouth and the upstream end of Tenasillahe Island
shown in figure 6-21 in the Application. The hatched area in figure 6-
21 represents the project area and amounts to roughly 377 square
kilometers (km\2\), yielding an approximate daily harbor seal density
of five individuals per km\2\ in the project area.
Table 7--Maximum Monthly Counts of Harbor Seals Detected During Low-Tide Aerial Surveys at Haulout Locations in the Lower Columbia River Estuary Between
1980 and 1983
[Adapted from Jeffries et al., 1984]
--------------------------------------------------------------------------------------------------------------------------------------------------------
N of
Month South Baker Desdemona Taylor Grays Miller Green Woody Total
Jetty Bay Sands Sands Bay Sands Island Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
January..................................................... 0 0 566 444 1 381 0 72 1,464
February.................................................... 0 NS NS NS NS * 200 NS 55 255
March....................................................... 1 0 * 650 548 0 82 0 3 1,284
April....................................................... 0 * 20 884 260 * 20 137 0 18 1,339
May......................................................... 0 1 568 4 4 0 16 0 593
June........................................................ 1 0 273 22 11 1 * 26 * 0 334
[[Page 20118]]
July........................................................ 0 0 525 21 10 0 38 0 594
August...................................................... 3 7 378 0 0 32 35 0 455
September................................................... 4 11 563 7 12 0 26 0 623
October..................................................... 0 * 25 223 59 0 6 0 0 313
November.................................................... NS NS * 230 NS NS NS NS NS 230
December.................................................... 0 0 301 174 0 46 0 0 521
--------------------------------------------------------------------------------------------------------------------------------------------------------
NS = Not Surveyed.
* Count based on visual estimate from airplane, boat, or jetty.
For harbor seals only, take by Level A and Level B harassment was
calculated based on the following equations, which were performed for
Level A and Level B harassment and for steel and timber piles:
Harassment = Harbor seal density * ensonified area * pile driving
workdays
The estimated isopleth areas associated with the longest pile dike
at each site are presented in table 8. These inputs were used in the
equation above to estimate the number of harbor seals possible within
those isopleths each day (table 9) and then calculate the overall level
of take based on the number of workdays projected in each year (table
10). The number of takes requested by Level A and Level B harassment by
the USACE for Year 1 through Year 5 are shown in table 10. The
calculated take by Level A harassment is likely an overestimate because
the likelihood of a harbor seal coming within a specified Level A
harassment isopleth of the pile and remaining long enough to experience
PTS during the brief period of potential impact driving that could be
needed to reach the last ~5 ft (1.5 m) of embedment depth is fairly
low. In addition, the USACE utilized the Level A harassment isopleth
area of the longest pile dike at each site, when in actuality, some
sites have shorter structures, and a pile dike is composed of multiple
individual piles with much smaller noise isopleths. NMFS concurs with
this assessment and will authorize harbor seal take according to the
totals contained in table 10.
Table 8--Pile Dike Lengths (m) and Corresponding Level A and Level B Harassment Areas
[km2]
----------------------------------------------------------------------------------------------------------------
All marine All marine All marine
Phocids level mammals Level mammals Level mammals Level
Site Pile dike A (km\2\) 24- B (km2) 24-in B (km2) 24-in B (km2) 12-in
length (m) in steel steel impact steel timber
impact vibratory vibratory
----------------------------------------------------------------------------------------------------------------
O-23.5-BN-ADD1.................. 22.40 0.213 0.74 37.29 81.45
O-23.5-BN-ADD2.................. 25.00 0.180 0.58 18.06 30.79
O-27.3-BN....................... 27.86 0.162 0.68 13.52 22.97
O-31.4-BN....................... 31.46 0.293 1.05 17.97 26.33
O-35.6-IW-D..................... 35.41 0.135 0.63 10.70 16.51
----------------------------------------------------------------------------------------------------------------
Table 9--Estimated Harbor Seals in Level A and Level B Harassment Zones per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
HS * in level A HS in Level B HS in Level B HS in Level B
isopleth area isopleth area isopleth area isopleth area
Site Installation timeframe 24-in steel 24-in steel 24-in steel 12-in timber
impact impact vibratory vibratory
--------------------------------------------------------------------------------------------------------------------------------------------------------
O-23.5-BN-ADD1.................................. LOA YR-3.......................... 2 4 187 408
O-23.5-BN-ADD2.................................. LOA YR-1.......................... 1 3 91 154
O-27.3-BN....................................... LOA YR-4.......................... 1 4 68 115
O-31.4-BN....................................... LOA YR-5.......................... 2 6 90 132
O-35.6-IW-D..................................... LOA YR-2.......................... 1 4 54 83
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 10--Calculated Level A and Level B Harassment Take for Harbor Seals During Pile Driving Activities Each Year
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steel pile Timber pile
Site driving driving Level A (steel Level B (steel Level B (timber
workdays workdays piles) piles) piles)
--------------------------------------------------------------------------------------------------------------------------------------------------------
YR-1.................................... O-23.5-BN-ADD2............. 13 12 26 2,405 4,896
YR-2.................................... O-35.6-IW-D................ 1 0 1 90 0
YR-3.................................... O-23.5-BN-ADD1............. 17 17 17 1,139 1,955
[[Page 20119]]
YR-4.................................... O-27.3-BN.................. 15 15 30 1,320 1,980
YR-5.................................... O-31.4-BN.................. 26 25 26 1,378 2,075
--------------------------------------------------------------------------------------------------------------------------------------------------------
California and Steller Sea Lions
Take estimates for California and Steller sea lions were based on
assumed daily abundances in the project area rather than the estimated
densities. The ODFW counted sea lions during recent aerial surveys of
three key haulout locations in the LCR. All sea lions detected in
winter are non-pup males and average counts of both California and
Steller sea lions observed during surveys between 2019 and 2022 are
shown in table 11. The haulout at East Mooring Basin (EMB) is just
south of the project area and likely downstream of pile driving
harassment isopleths. The USACE used the average counts observed at EMB
(RM 15 (25 km) from there) as a proxy for sea lions that may be present
during pile driving and used the average across all winter months as a
proxy for the number of sea lions in the project area since that
haulout is closer to the project area (RM 23 (37 km) to RM 36 (57.9
km)) compared to the Rainer (RM 67 (107.8 km)) and Coffin Rock (RM 72
115.9 km)) locations. Based on counts of sea lions at the EMB site
(table 11), the USACE estimated 182 California sea lions and 3 Steller
sea lions by Level B harassment per day in the project vicinity. Level
A harassment is not likely since the Level A harassment zones for
otariids are smaller than the shutdown zone calculated (15-20 m) for
all pile driving scenarios as shown in table 9, and no such take is
authorized.
Table 11--Average Counts of California and Steller Sea Lions Detected at Haulout Locations Depicted in Figure 4-
2 During ODFW Winter Aerial Surveys, 2019-2022
[USACE, 2024]
----------------------------------------------------------------------------------------------------------------
Haulout site Month Average of CSL Average of SSL
----------------------------------------------------------------------------------------------------------------
East Mooring Basin (EMB).................. November.................... 128 0
December.................... 234 3
January..................... 166 4
February.................... 197 5
----------------------------------------------------------------------------------------------------------------
Take estimates for California and Steller sea lions were calculated
based on the equation below and number of workdays shown in table 12:
Level B exposure = N animals/day * total driving days
There could be 25 total days of noise exposure from pile driving
during year 1 (YR-1); 34 days in YR-3; 30 days in YR-4, and up to 51
days in YR-5.
Table 12--Authorized Take by Level B Harassment for California and Steller Sea Lions Likely To Be in the Project
Vicinity
----------------------------------------------------------------------------------------------------------------
Total pile driving
workdays Level B harassment CSL Level B harassment SSL
----------------------------------------------------------------------------------------------------------------
YR-1................................. 25 4,550 75
YR-2................................. 1 182 3
YR-3................................. 34 6,188 102
YR-4................................. 30 5,460 90
YR-5................................. 51 9,282 153
----------------------------------------------------------------------------------------------------------------
The annual and total number of takes of marine mammal species
requested by the USACE and authorized for take by NMFS are shown in
table 13.
Table 13--Authorized Takes by Level A Harassment and Level B Harassment Annually Over 5 Years
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Yr 1 Yr 2 Year 3 Yr 4 Yr 5 5-Yr total
Species Stock -----------------------------------------------------------------------------------------------------------------------
Level A Level B Level A Level B Level A Level B Level A Level B Level A Level B Level A Level B
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal............................... OR/WA Coastal............... 26 7,301 1 90 17 3,094 30 3,300 26 3,453 87 17,238
California sea lion....................... U.S......................... ........ 4,550 ........ 182 ........ 6,188 ........ 5,460 ........ 9,282 ........ 25,662
Steller sea lion.......................... Eastern..................... ........ 75 ........ 3 ........ 102 ........ 90 ........ 153 ........ 423
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 20120]]
To inform both the negligible impact analysis and the small numbers
determination, NMFS assesses the maximum number of takes of marine
mammals that could occur within any given year during the effective LOA
period. In this calculation, the maximum estimated number of Level A
harassment takes in any one year is summed with the maximum estimated
number of Level B harassment takes in any one year for each species to
yield the highest number of estimated take that could occur in any year
(table 14). Table 14 also depicts the number of takes that will be
authorized by NMFS relative to the abundance of each stock.
Table 14--Maximum Number of Authorized Takes (by Level A Harassment and Level B Harassment) That Could Occur in
Any One Year of the Project Relative to Stock Population Size
----------------------------------------------------------------------------------------------------------------
Total percent
stock taken
Species NMFS stock Maximum Level Maximum Level Maximum annual based on
abundance A harassment B harassment take \1\ maximum annual
take
----------------------------------------------------------------------------------------------------------------
Harbor seal.................... \2\ 24,732 30 7,301 7,331 29.6
California sea lion............ 257,606 .............. 9,282 9,282 3.6
Steller sea lion............... 36,308 .............. 153 153 <0.01
----------------------------------------------------------------------------------------------------------------
\1\ Calculations of the maximum annual take are based on the maximum requested Level A harassment take in any
one year + the total requested Level B harassment take in any one year.
\2\ The Oregon/Washington Coastal Stock was most recently estimated at 24,732 harbor seals in 1999 and more
recent abundance data is not available (Carretta et al., 2022).
Mitigation
Under section 101(a)(5)(D)(ii) of the MMPA, NMFS must set forth (1)
``the permissible methods of taking pursuant to the activity'' and (2)
``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.'' 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 2 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 (e.g., likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented (i.e.,
probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (i.e., probability
of being 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 measures described in the following sections would
apply to the USACE in-water construction activities.
Shutdown, Harassment, and Monitoring Zones
USACE will employ shutdown, harassment, and monitoring zones in
order to mitigate harm to marine mammals. Shutdown zones are areas in
which pile driving will stop if any marine mammal enters and are
pictured/identified in table 15. In most impact and pile driving
scenarios, the shutdown zones exceed the calculated Level A isopleths,
meaning that no marine mammal is expected to enter a shutdown zone
except during impact pile driving of 24-in steel piles for phocids
(e.g. harbor seals) when the calculated Level A harassment isopleth
(130.6 m) exceeds the 50-m shutdown zone. There was concern that the
potential for seals to enter into a shutdown zone of 130 m would result
in frequent delays and could impede the project's schedule. The
shutdown zone will be established at 50 m for phocid pinnipeds during
impact driving of 24-in steel piles to provide adequate protection
without unnecessary delay, thereby meeting the statutory
``practicable'' standard.
Table 15--Shutdown Zones and Level B Monitoring Zones by Activity
----------------------------------------------------------------------------------------------------------------
Shutdown zone (m)
Pile size and type -------------------------------- Level B
Phocid Otariid harassment (m)
----------------------------------------------------------------------------------------------------------------
Vibratory Pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile................................................ 50 15 3,981.1
12-in timber pile............................................... 60 20 6,309.6
----------------------------------------------------------------------------------------------------------------
Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile................................................ 50 50 464.2
12-in timber pile............................................... 15 15 21.5
----------------------------------------------------------------------------------------------------------------
[[Page 20121]]
Prior to pile driving, PSOs will survey the shutdown zones shown in
table 15 and surrounding areas for at least 30 minutes before pile
driving activities start. If marine mammals are found within the
shutdown zone, pile driving will be delayed until the animal has moved
out of the shutdown zone, either verified by a PSO or by waiting until
15 minutes has elapsed without a sighting. If a marine mammal
approaches or enters the shutdown zone during pile driving, the
activity will be halted. Pile driving may resume after the animal has
moved out of the shutdown zone or after at least 15 minutes has passed
since the last observation of the animal.
All marine mammals will be monitored in the Level B harassment zone
to the extent of visibility for the on-duty PSOs. If a marine mammal
for which take is authorized enters the Level B harassment zone, in-
water activities will continue and PSOs would document the animal's
presence within the estimated harassment zone.
If a species for which authorization has not been granted, or for
which the authorized takes are met, is observed approaching or within
the Level B harassment zone, pile driving activities will be shut down
immediately. Activities would not resume until the animal has been
confirmed to have left the area or 15 minutes has elapsed with no
sighting of the animal. If a Shutdown Zone is obscured by fog or other
weather/sea conditions that restrict the observers' ability to observe,
pile driving will not be initiated or would cease until the entire
Shutdown Zone is visible so that monitoring may resume.
PSOs
The placement of PSOs during all pile driving and removal
activities (described in detail in the Monitoring and Reporting section
and Marine Mammal Monitoring Plan) will ensure that the project area is
monitored to the maximum extent possible based on the required number
of PSOs, required monitoring locations, and environmental conditions.
Pre- and Post-Activity Monitoring
Monitoring must take place from 30 minutes prior to initiation of
pile driving activities (i.e., pre-clearance monitoring) through 30
minutes post-completion of pile driving. Prior to the start of daily
in-water construction activity, or whenever a break in pile driving of
30 minutes or longer occurs, PSOs will observe the shutdown and
monitoring zones for a period of 30 minutes. The shutdown zone will be
considered cleared when a marine mammal has not been observed within
the zone for a 30-minute period. If a marine mammal is observed within
the shutdown zones, pile driving activity will be delayed or halted. If
work ceases for more than 30 minutes, the pre-activity monitoring of
the shutdown zones will commence. A determination that the shutdown
zone is clear must be made during a period of good visibility (i.e.,
the entire shutdown zone and surrounding waters must be visible to the
naked eye).
Bubble Curtain
A bubble curtain must be employed during all impact pile driving
activities. The bubble curtain must distribute air bubbles around 100
percent of the piling circumference for the full depth of the water
column. The lowest bubble ring must be in contact with the mudline for
the full circumference of the ring. The weights attached to the bottom
ring must ensure 100 percent substrate contact. No parts of the ring or
other objects may prevent full substrate contact. Air flow to the
bubblers must be balanced around the circumference of the pile.
Soft Start
Soft-start procedures are believed to provide additional protection
to marine mammals by providing warning and/or giving marine mammals a
chance to leave the area prior to the impact hammer operating at full
capacity. For impact driving, an initial set of three strikes will be
made by the hammer at reduced energy, followed by a 30-second waiting
period, then 2 subsequent 3-strike sets before initiating continuous
driving. Soft start will 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.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the required 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.
Monitoring and Reporting
In order to issue an LOA 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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> 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);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either long-
term fitness and survival of individual marine mammals or populations,
species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Marine mammal monitoring during pile driving and removal associated
with this project must be conducted by NMFS-approved PSOs as follows:
<bullet> PSOs must be independent of the contractor employed by
USACE to conduct the project (e.g., employed by a subcontractor) and
have no other assigned tasks during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> Other PSOs may substitute education (i.e., degree in
biological science or related field) or training for
[[Page 20122]]
prior experience performing the duties of a PSO during construction
activity pursuant to a NMFS-issued incidental take authorization;
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator must be designated. The lead
observer must have prior experience performing the duties of a PSO
during construction activity pursuant to a NMFS-issued incidental take
authorization;
<bullet> PSOs must record all observations of marine mammals as
described in the Marine Mammal Monitoring Plan, regardless of distance
from the pile being driven. PSOs shall document any behavioral
reactions in concert with distance from piles being driven or removed.
PSOs must have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> 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
<bullet> 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.
The USACE must employ a minimum of two PSOs. PSO locations will
provide an unobstructed view of all water within the shutdown zone(s)
and as much of the Level A harassment and Level B harassment zones as
possible. PSOs will be stationed along the shore of the LCR. One will
be located on the closest shoreline or construction barge adjacent to
planned pile driving and another observer could be stationed on a
publicly accessible shoreline with a different vantage point of the
disturbance area or be boat-based.
The USACE will ensure that construction supervisors and crews, the
monitoring team, and relevant USACE staff are trained prior to the
start of activities subject to the LOA, so that responsibilities,
communication procedures, monitoring protocols, and operational
procedures are clearly understood. New personnel joining during the
project will be trained prior to commencing work. Monitoring will occur
for all in-water pile driving activities during the pile installation
work window (November 1 to February 28 (or February 29 in a leap year).
Data Collection
PSOs will use approved data forms to record the following
information:
<bullet> Dates and times (beginning and end) of all marine mammal
monitoring;
<bullet> PSO locations during marine mammal monitoring;
<bullet> Construction activities occurring during each daily
observation period, including how many and what type of piles were
driven or removed and by what method (i.e., vibratory, impact);
<bullet> Weather parameters and water conditions;
<bullet> The number of marine mammals observed, by species,
relative to the pile location and if pile driving or removal was
occurring at time of sighting;
<bullet> Distance and bearings of each marine mammal observed to
the pile being driven or removed;
<bullet> Description of marine mammal behavior patterns, including
direction of travel;
<bullet> Age and sex class, if possible, of all marine mammals
observed; and
<bullet> Detailed information about implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting behavior of the animal if
any.
Reporting
The USACE must submit a draft monitoring report to NMFS within 90
calendar days of the completion of each construction year. A draft
comprehensive 5-year summary report must also be submitted to NMFS
within 90 days of the end of the effective period of the LOA. The
reports must detail the monitoring protocol and summarize the data
recorded during monitoring. Final annual reports and the final
comprehensive report must be prepared and submitted within 30 days
following resolution of any NMFS comments on the draft report. If no
comments are received from NMFS within 30 days of receipt of the draft
report, the report must be considered final. If comments are received,
a final report addressing NMFS comments must be submitted within 30
days after receipt of comments. The marine mammal report would include
an overall description of work completed, a narrative regarding marine
mammal sightings, and associated PSO data sheets. Specifically, the
report must include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including the number and type of piles driven or
removed and by what method (i.e., vibratory driving) and the total
equipment duration for cutting for each pile;
<bullet> PSO locations during marine mammal monitoring;
<bullet> 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;
<bullet> Upon observation of a marine mammal, the following
information: (1) name of PSO who sighted the animal(s) and PSO location
and activity at time of sighting; (2) time of sighting; (3)
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; (4)
distance and bearing of each marine mammal observed relative to the
pile being driven for each sighting (if pile driving was occurring at
time of sighting); (5) estimated number of animals (min/max/best
estimate); (6) estimated number of animals by cohort (e.g., adults,
juveniles, neonates, group composition, etc.); (7) animal's closest
point of approach and estimated time spent within the harassment zone;
and (8) 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);
<bullet> Number of marine mammals detected within the harassment
zones, by species; and
<bullet> Detailed information about any implementation of any
mitigation triggered (e.g., shutdowns and delays), a description of
specific actions that ensued, and resulting changes in behavior of the
animal(s), if any.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the USACE will report the
incident to the Office of Protected Resources (OPR),
[[Page 20123]]
NMFS, and to the West Coast regional stranding network as soon as
feasible. If the death or injury was clearly caused by the specified
activity, the USACE must 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 terms of the LOA. The USACE must not resume their
activities until notified by NMFS. The report must include the
following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> 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).
The analysis that follows applies to California sea lions, Steller
sea lions, and harbor seals, given that the anticipated effects of this
activity on these different marine mammal stocks are expected to be
similar since they have comparable behavioral sensitivities and,
therefore, no meaningful differences in terms of likely impacts. 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 as regards the
different species.
Vibratory and impact pile driving activities have the potential to
disturb or displace marine mammals. Specifically, the project
activities may result in take, in the form of Level A harassment and
Level B harassment from underwater sounds generated from pile driving
and removal. Potential takes could occur if individuals are present in
the ensonified zone when these activities are underway.
The takes from Level B harassment would be due to potential
behavioral disturbance and TTS. Level A harassment takes would be due
to auditory injury. No mortality or serious injury is anticipated given
the nature of the activity, even in the absence of the required
mitigation. The potential for harassment is minimized through the
construction method and the implementation of the required mitigation
measures (see Mitigation section).
Take would occur within a limited, confined area (the LCR) of the
stocks' ranges. The duration and intensity of authorized harassment
events would be minimized through use of mitigation measures described
herein. Further, the amount of take authorized is small when compared
to stock abundance, and the project is not anticipated to impact any
known important habitat areas for any marine mammal species.
Take by Level A harassment is authorized for a single species
(harbor seal) to account for the potential that an animal could enter
and remain within the area between a Level A harassment zone and the
shutdown zone for a duration long enough to experience a take via Level
A harassment. Limited take by Level A harassment is expected to arise
from, at most, a small degree of auditory injury during impact driving,
which will only be used briefly to achieve the final 5-ft (1.5 m) of
embedment depth for a given pile. Animals would need to be exposed to
higher levels and/or longer duration in order to incur any more than a
small degree of auditory injury. 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 auditory
injury or TTS potentially incurred here would not be expected to
adversely impact individual fitness, let alone annual rates of
recruitment or survival.
Marine mammal behavioral responses to pile driving, if any, are
expected to be mild and temporary. Marine mammals found within the
Level B harassment zone may not show any visual cues they are disturbed
by activities or they could become alert, avoid the area, leave the
area, or display other mild responses that are not observable such as
changes in vocalization patterns. Given the limited number of piles to
be installed per day and that pile driving would occur across a range
of 1 to 51 days between November 1 and February 28 or February 29 in a
leap year over the 5-year effective period of the LOA, the effects of
any harassment would be temporary.
Impacts on marine mammal prey that would occur during the USACE's
planned activity would 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. Indirect effects on marine mammal prey
during the construction are expected to be minor, and these effects are
unlikely to cause substantial effects on marine mammals at the
individual level, with no expected effect on annual rates of
recruitment or survival.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the stocks' annual
rates of recruitment or survival. In combination, we believe that these
factors, as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities will have only minor, short-term effects on individuals. The
specified activities are not expected to impact rates of recruitment or
survival and will therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our determination that the impacts resulting from this activity
are not expected to adversely affect any of the species or stocks
through effects on annual rates of recruitment or survival:
[[Page 20124]]
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> The intensity of anticipated takes by Level B harassment
is relatively low for all stocks and would not be of a duration or
intensity expected to result in impacts on reproduction or survival;
<bullet> No important habitat areas have been identified within the
project area;
<bullet> For species authorized for take, the project area is a
very small and peripheral part of their range and anticipated habitat
impacts are minor;
<bullet> The USACE would implement mitigation measures, such as
bubble curtains and soft-starts for impact pile driving; and
<bullet> Monitoring and shutdowns would minimize the numbers of
marine mammals exposed to injurious levels of sound to ensure that take
by Level A harassment would result, at most, in a small degree of
auditory injury.
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 required monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the planned 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 sections 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. See 86 FR 5322, 5439 (Jan. 19,
2021). Additionally, other qualitative factors may be considered in the
analysis, such as the temporal or spatial scale of the activities.
Table 14 demonstrates the maximum number of Level A and Level B
harassment events per year. Our analysis shows that no more than 29.6
percent of harbor seals, 3.6 percent of California sea lions and less
than 0.01 percent of Steller sea lions could be taken by Level A and
Level B harassment. The numbers of animals authorized to be taken for
these stocks would be considered small relative to the relevant stock's
abundances, even if each estimated taking occurred to a new
individual--an extremely unlikely scenario.
Based on the analysis contained herein of the planned activity
(including the required mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS 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.
Adaptive Management
The regulations governing the take of marine mammals incidental to
the USACE's construction activities contains an adaptive management
component. The reporting requirements associated with this rule are
designed to provide NMFS with monitoring data from completed projects
to allow consideration of whether any changes are appropriate. The use
of adaptive management allows NMFS to consider new information from
different sources to determine (with input from the USACE regarding
practicability) on an annual or biennial basis if mitigation or
monitoring measures should be modified (including additions or
deletions). Mitigation measures could be modified if new data suggests
that such modifications would have a reasonable likelihood of reducing
adverse effects to marine mammals and if the measures are practicable.
The following are some of the possible sources of applicable data
could be considered through the adaptive management process: (1)
results from monitoring reports, as required by MMPA authorizations;
(2) results from general marine mammal and sound research; and (3) any
information which reveals that marine mammals may have been taken in a
manner, extent, or number not authorized by these regulations or LOAs
issues pursuant to these regulations. See Sec. 217.77(c) below.
National Environmental Policy Act
To comply with NEPA (42 U.S.C. 4321 et seq.) and NOAA
Administrative Order (NAO) 216-6A, NMFS must review our action (i.e.,
promulgation of regulations and subsequent issuance of a 5-year LOA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs 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 determined that the action
qualifies to be categorically excluded from further review under NEPA.
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 incidental take
authorizations, NMFS consults internally whenever NMFS authorizes take
for endangered or threatened species.
No incidental take of ESA-listed species is authorized 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.
Classification
The Office of Management and Budget has determined that this rule
is not significant for purposes of Executive Order 12866.
Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA),
the Chief Counsel for Regulation of the Department of Commerce
certified to the Chief Counsel for Advocacy of the Small Business
Administration at the proposed rule stage that this action will not
have a significant economic impact on a substantial number of small
entities. No comments were received regarding this certification or on
the economic impacts of the rule more generally. As a result, a
regulatory flexibility analysis is not required and none has been
prepared.
This rule does not contain a collection-of-information requirement
[[Page 20125]]
subject to the provisions of the Paperwork Reduction Act because the
applicant is a Federal agency.
List of Subjects in 50 CFR 217
Acoustics, Administrative practice and procedure, Construction,
Endangered and threatened species, Marine mammals, Mitigation and
Monitoring requirements, Reporting requirements, and Wildlife.
Dated: May 5, 2025.
Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
For the reasons set forth in the preamble, NMFS amends 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 H to read as follows:
Subpart H--Taking Marine Mammals Incidental to the Lower Columbia
River Dredged Material Management Plan, Oregon and Washington
Sec.
217.70 Specified activity and geographical region.
217.71 Effective dates.
217.72 Permissible methods of taking.
217.73 Prohibitions.
217.74 Mitigation requirements.
217.75 Requirements for monitoring and reporting.
217.76 Letters of Authorization.
217.77 Renewals and modifications of Letters of Authorization.
217.78-217.279 [Reserved]
Sec. 217.70 Specified activity and geographical region.
(a) Regulations in this subpart apply only to the United States
Army Corps of Engineers (USACE) and those persons it authorizes or
funds to conduct construction activities, including maintenance and
replacement of piles, as designated in the Lower Columbia River Dredged
Material Management Plan, Oregon and Washington on its behalf that
result in the incidental taking of marine mammals that occur in the
areas outlined in paragraph (b) of this section. Requirements imposed
on the USACE pursuant to this subpart must be implemented by those
persons it authorizes or funds to conduct activities on its behalf.
(b) The taking of marine mammals by the USACE may be authorized in
a Letter of Authorization (LOA) only if it occurs near the Mouth of the
Columbia River in Oregon and Washington.
Sec. 217.71 Effective dates.
Regulations in this subpart are effective from November 1, 2027,
through February 29, 2032.
Sec. 217.72 Permissible methods of taking.
Under an LOA issued pursuant to Sec. 216.106 of this chapter and
Sec. 217.76, the Holder of the LOA (hereinafter ``USACE'') may
incidentally, but not intentionally, take marine mammals within the
area described in Sec. 217.70 (b) by harassment associated with
construction activities, provided the activity is in compliance with
all terms, conditions, and requirements of the regulations in this
subpart and the applicable LOA.
Sec. 217.73 Prohibitions.
(a) It is unlawful for any person to do any of the following in
connection with the activities described in Sec. 217.70:
(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. 217.74 Mitigation requirements.
(a) When conducting the activities identified in Sec. 217.70(a),
the mitigation measures contained in any LOA issued under this subpart
must be implemented. These mitigation measures include but are not
limited to:
(1) A copy of the LOA must be in the possession of the USACE,
supervisory construction personnel, lead protected species observers
(PSOs), and any other relevant designees of the USACE operating under
the authority of the LOA at all times that activities subject to the
LOA are being conducted.
(2) The USACE shall conduct training for supervisors and crews, the
PSO team, and relevant USACE staff prior to the start of construction
activity subject to this rule, so that responsibilities, communication
procedures, monitoring protocols, and operational procedures are
clearly understood. New personnel joining during the project must be
trained in the aforementioned matters prior to commencing work.
(3) The USACE must employ PSOs and establish monitoring locations
as described in the Marine Mammal Monitoring Plan. The USACE must
monitor the harassment zones to the maximum extent possible based on
the required number of PSOs, required monitoring locations, and
environmental conditions.
(4) 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.
(5) 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. Pile driving may commence
following 30 minutes of diligent observation after which it is
determined that the shutdown zones are clear of marine mammals.
(6) For all pile driving activity, the USACE must implement
shutdown zones with radial distances as identified in a LOA issued
under this subpart.
(7) If a marine mammal is observed entering or within the shutdown
zones, pile driving activity must be delayed or halted. Pile driving
must be commenced or resumed as described in Sec. 217.74(a)(8).
(8) 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 to be beyond
the shutdown zone or 15 minutes have passed without re-detection of the
animal within the shutdown zone.
(9) The USACE must avoid direct physical interaction with marine
mammals during construction activity. If a marine mammal comes within
15 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.
(10) The USACE must use soft start techniques when impact pile
driving. Soft start requires contractors to provide an initial set of
three strikes from the hammer at reduced energy, followed by a 30-
second waiting period. Then two subsequent reduced-energy strike sets
would occur. A soft start must be implemented at the start of each
day's
[[Page 20126]]
impact pile driving and at any time following cessation of impact pile
driving for a period of 30 minutes or longer.
(11) The USACE must employ bubble curtain systems during all impact
driving except where the water depth is less than 0.67 m (2 ft) in
depth. Bubble curtains must meet the following requirements:
(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) The bubble curtain must be operated such that there is equal
balancing of air flow to all bubblers.
(12) 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.
(13) Pile driving activity must be halted upon observation of a
species for which either incidental take is not authorized or the
authorized number of takes has been met entering or within the
harassment zone.
(b) [Reserved]
Sec. 217.75 Requirements for monitoring and reporting.
(a) The USACE must submit a Marine Mammal Monitoring Plan
(Monitoring Plan) to NMFS for approval at least 90 days in advance of
construction. Marine mammal monitoring must be conducted in accordance
with the conditions in this section and the approved Monitoring Plan.
(b) Monitoring must be conducted by qualified, NMFS-approved PSOs,
in accordance with the following conditions:
(1) PSOs must be independent of the activity contractor (for
example, employed by a subcontractor) and have no other assigned tasks
during monitoring periods.
(2) At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization.
(3) Other PSOs may substitute other relevant experience, education
(i.e., 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.
(4) Where a team of three or more PSOs is required, a lead observer
or monitoring coordinator must be designated. The lead observer must
have prior experience performing the duties of a PSO during
construction activity pursuant to a NMFS-issued incidental take
authorization.
(5) PSOs must record all observations of marine mammals as
described in the Monitoring Plan, regardless of distance from the pile
being driven. PSOs shall document any behavioral reactions in concert
with distance from piles being driven or removed.
(c) The USACE must establish monitoring locations as described in
the Monitoring Plan. For all pile driving activities, a minimum of 1
PSO must be assigned to each active pile driving location to monitor
the shutdown zones.
(d) The USACE must submit a draft monitoring report to NMFS within
90 calendar days of the completion of each construction year. A draft
comprehensive 5-year summary report must also be submitted to NMFS
within 90 days of the end 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 reports, the reports must be considered final. If comments are
received, final annual reports and the final comprehensive report
addressing NMFS comments must be submitted within 30 days after receipt
of comments. The reports must contain the informational elements
described at minimum below including:
(1) Dates and times (beginning 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) PSO locations during marine mammal monitoring;
(4) 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 (if less
than the harassment zone distance);
(5) Upon observation of a marine mammal, the following information
should be collected:
(i) PSO who sighted the animal, PSO location, and construction
activity at time of sighting:
(ii) Time of sighting;
(iii) 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;
(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) Minimum, maximum, and best estimated number of animals;
(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., feeding or traveling), including an assessment of behavioral
responses to the construction activity (e.g., no response or changes in
behavioral state such as ceasing feeding, changing direction, flushing,
or breaching);
(ix) Number of marine mammals detected within the harassment zones
by species.
(x) 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
(xi) All PSO datasheets and/or raw sightings data.
(e) In the event that personnel involved in the construction
activities discover an injured or dead marine mammal, the USACE must
report the incident to NMFS Office of Protected Resources (OPR) and to
the West Coast Regional Stranding Coordinator as soon as feasible. If
the death or injury was caused by the specified activity, the USACE
must immediately cease the specified activities until NMFS OPR is able
to review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of this rule and the LOA issued under Sec. 216.106 and Sec. 217.76.
The USACE 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;
[[Page 20127]]
(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. 217.76 Letters of Authorization.
(a) To incidentally take marine mammals pursuant to these
regulations, the USACE 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 expiration date of these regulations.
(c) If an LOA expires prior to the expiration date of these
regulations, the USACE 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 USACE must
apply for and obtain a modification of the LOA as described in Sec.
217.77.
(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 these regulations.
(g) Notice of issuance or denial of an LOA must be published in the
Federal Register within 30 days of a determination.
Sec. 217.77 Renewals and modifications of Letters of Authorization.
(a) An LOA issued under Sec. 216.106 of this chapter and Sec.
217.76 for the activity identified in Sec. 217.70(a) may be renewed or
modified upon request by the applicant, 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 these regulations; and
(2) NMFS determines that the mitigation, monitoring, and reporting
measures required by the previous LOA under these regulations were
implemented.
(b) For LOA modification or renewal requests by the applicant that
include changes to the activity or the mitigation, monitoring, or
reporting that do not change the findings made as the basis of these
regulations 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) An LOA issued under Sec. 216.106 of this chapter and Sec.
217.76 for the activity identified in Sec. 217.70 (a) may be modified
by NMFS under the following circumstances:
(1) NMFS may modify (including augment) the existing mitigation,
monitoring, or reporting measures (after consulting with USACE
regarding the practicability of the modifications) if doing so creates
a reasonable likelihood of more effectively accomplishing the goals of
the mitigation and monitoring set forth in the preamble for these
regulations;
(i) Possible sources of data that could contribute to the decision
to modify the mitigation, monitoring, or reporting measures in an LOA:
(A) Results from USACE's monitoring from previous years;
(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 these regulations or
subsequent LOAs; and
(ii) If, through adaptive management, the modifications to the
mitigation, monitoring, or reporting measures are substantial, NMFS
must 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. 216.106 of this
chapter and Sec. 217.76, a LOA may be modified without prior notice or
opportunity for public comment. Notification would be published in the
Federal Register within 30 days of the action.
Sec. Sec. 217.78-217.79 [Reserved]
[FR Doc. 2025-08231 Filed 5-9-25; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on May 12, 2025.
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