Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Lower Columbia River Dredged Material Management Plan, Oregon and Washington, 89543-89568 [2024-26069]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 89, Number 219 (Wednesday, November 13, 2024)]
[Proposed Rules]
[Pages 89543-89568]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-26069]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 241104-0288]
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: Proposed rule, request for comments.

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SUMMARY: NMFS has received a request from the U.S. Army Corps of 
Engineers, for Incidental Take Regulations (ITR) and Letter of 
Authorization (LOA) pursuant to the Marine Mammal Protection Act. The 
requested regulations would govern the authorization of take of small 
numbers of marine mammals over 5 years (2027-2032) incidental to the 
Lower Columbia River Dredged Material Management Plan in Oregon and 
Washington. NMFS requests public comments and will consider them prior 
to making any final decision on the requested ITR and issuance of the 
LOA; agency responses to comments will be summarized in the final rule, 
if issued.

DATES: Comments and information must be received no later than December 
13, 2024.

ADDRESSES: A plain language summary of this proposed rule is available 
at: https://www.regulations.gov/docket/NOAA-NMFS-2024-0123.
     Electronic Submissions: Submit all electronic public 
comments via the Federal e-Rulemaking Portal. Go to https://www.regulations.gov and enter NOAA-NMFS-2024-0123 in the Search box 
(note: copying and pasting the FDMS Docket Number directly from this 
document may not yield search results). Click on the ``Comment'' icon, 
complete the required fields, and enter or attach your comments.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by the National Marine Fisheries Service (NMFS). 
All comments received are a part of the public record and will 
generally be posted for public viewing at: https://www.regulations.gov 
without change. All personal identifying information (e.g., name, 
address, etc.), confidential business information, or otherwise 
sensitive information submitted voluntarily by the sender will be 
publicly accessible. NMFS will accept anonymous comments (enter ``N/A'' 
in the required fields if you wish to remain anonymous).

FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: A copy of the U.S. Army Corps of Engineers' 
(USACE) application any supporting documents, as well as a list of the 
references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-us-army-corps-engineers-lower-columbia-river-dredged-material. In case of 
problems accessing these documents, please call the contact listed 
above (see FOR FURTHER INFORMATION CONTACT).

Purpose and Need for Regulatory Action

    This proposed rule, if adopted, would establish a framework under 
the authority of the Marine Mammal Protection Act (MMPA) (16 U.S.C. 
1361 et seq.) to authorize, for a 5-year period (2027-2032), take of 
marine mammals incidental to the USACE's construction activities 
associated with the Lower Columbia River (LCR) Dredged Materials 
Management Plan (DMMP). NMFS received an application (the Application) 
from the USACE requesting 5-year regulations and an LOA to take 3 
species of marine mammals. Take would occur by harassment only, 
incidental to impact and vibratory pile driving. 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

[[Page 89544]]

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). No mortality or serious injury is 
anticipated or proposed for authorization.

Legal Authority for the Proposed Action

    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, regulations are 
promulgated, and public notice and an opportunity for public comment 
are provided.
    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 as ``mitigation''); 
and requirements pertaining to the mitigation, monitoring and reporting 
of the takings are set forth. The definitions of all applicable MMPA 
statutory terms cited above are included below.
    Section 101(a)(5)(A) of the MMPA and the implementing regulations 
at 50 CFR part 216, subpart I, provide the legal basis for proposing 
and, if appropriate, issuing 5-year regulations and an associated LOA. 
This proposed rule also establishes required mitigation, monitoring, 
and reporting requirements for the USACE's activities.

Summary of Major Provisions Within the Proposed Rule

    The following is a summary of the major provisions of this proposed 
rule regarding USACE construction activities. These provisions include 
measures requiring:
     Monitoring of the construction areas to detect the 
presence of marine mammals before beginning construction activities;
     Shutdown of construction activities under certain 
circumstances to avoid injury of marine mammals;
     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
     Use of bubble curtains to attenuate sound levels when 
impact driving.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA) 
(42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must evaluate the proposed action (i.e., promulgation of 
regulations and subsequent issuance of a 5-year LOA) and alternatives 
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 preliminarily determined 
that issuance of the proposed rule qualifies to be categorically 
excluded from further NEPA review.
    Information in the USACE Application and this document collectively 
provide the environmental information related to proposed issuance of 
these regulations and subsequent incidental take authorization for 
public review and comment. We will review all comments submitted in 
response to this notice of proposed rulemaking prior to concluding our 
NEPA process and prior to making a final decision on the request for 
incidental take authorization.

Summary of USACE Request

    On October 18, 2023, NMFS received an Application from the USACE 
requesting authorization for take of 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.
    The USACE requests authorization to take 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 proposed regulations would be 
valid for 5 years (2027-2032).

Description of Proposed Activity

Overview

    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 DMMP includes proposed dredging and placement 
operations between river miles (mi) (RM) 3 and 105.5. However, the 
scope of this request for an 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 proposing 
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 proposed.

Dates and Duration

    The proposed regulations would be valid for a period of 5 years 
from November 1, 2027, through February 29, 2032. Pile driving is 
expected to occur during the in-water work window of the LCR of 
November 1 through February 28. An estimated 141 in-water workdays 
would occur during this period, with a minimum of 1 day occurring in 
LOA year 2 (November 2028-February 2029) and a maximum of 51 days in 
LOA year 5 (November 2031-February 2032). The USACE estimated the 
number of in-water workdays based on the assumption that an average of 
15 piles would be installed in a given day. However, contractors could 
install up to 20 piles in a day under favorable conditions, and thus 
the final total number of workdays may be less than anticipated.

Specific Geographic Region

    The LCR flows 146 miles from Bonneville Dam to the Pacific Ocean. 
This reach of the river features fish and wildlife in the transition 
from fresh water to salt water, passing through major cities and towns, 
flowing through wildlife refuges, supporting ports and a

[[Page 89545]]

shipping channel, and providing valued recreation opportunities. The 
LCR features a meandering geometry composed of gradual bends with flows 
splitting around in-river islands. Several of these in-river islands 
were expanded or created entirely from dredged material that was placed 
to help maintain the dimensions of the FNC. Work will take place from 
RM 23 to RM 36 as shown in figure 1. The project area encompasses this 
section of the river, which features widely dispersed housing 
structures separated by stretches of undeveloped land to the north on 
the right bank and uninhabited islands and sand flats south of the 
navigation channel (hereinafter, the Project Area). Traveling from west 
to east these are Rice Island, Miller Sands, Snag Island, Pillar Rock 
Island, Jim Crowe Sands, Woody Island, Grassy Island, Fitzpatrick 
Island, and Welch Island, which are all part of the Lewis and Clark 
National Wildlife Refuge. Tenasillaha Island, which is part of the 
Julia Hanson Butler National Wildlife Refuge, is the easternmost island 
in the Project Area. The main navigation channel from RM 3 to RM 105.5 
must be maintained at 48 feet (ft) deep and, generally, 600 ft wide.

Figure 1--Locations of Proposed Installation Sites on the Lower 
Columbia River
[GRAPHIC] [TIFF OMITTED] TP13NO24.014

Detailed Description of the Specified Activity

    There are a number of channel maintenance practices utilized by the 
USACE as part of the LCR DMMP. Channel deepening and widening requires 
regular maintenance dredging to remove shoals that form in the 
navigation channel. The standard of maintenance dredging has been to 
dredge material from areas in which navigation is affected, and to 
dispose of the dredged material in upland or shoreline placement sites 
or areas of the navigation channel where the channel is deeper, 
referred to as ``flow lane placement.'' Dredged materials have 
historically been placed between or adjacent to pile dike structures to 
supplement natural accretion of sediment. Hopper dredging, clamshell 
dredging, and pipeline dredging are all employed for channel deepening 
and widening and are employed as part of the DMMP. These operations are 
described in greater detail in the USACE Application. NMFS, however, 
has determined that dredging is not likely to result in harassment 
under the MMPA.
    The USACE employs a number of river control structures to help 
maintain the dimensions of the FNC. For example, placing dredged 
material along the shallow water banks of an existing island serves to 
redirect flow back into the main navigation channel and narrow the 
width of the river, which mimics a natural scouring process of the 
riverbed. Dredged material has been used to build or expand channel 
training landforms such as in-river islands that reduce the river's 
cross-section and control channel alignment to aid in maintaining the 
navigation channel's dimensions. The purpose of reducing the river's 
cross-section is to increase and redirect flow velocities in localized 
areas back into the navigation channel to create natural scouring 
action. Piles are the most common channel training structure in the LCR 
and may or may not be associated with in-river islands. Such piles can 
be used along a shoreline, or as part of an island and are often 
installed perpendicular to the direction of river flow. The pile dike 
slows the velocity of the river along the shoreline which reduces 
erosion and redirects the flow such that the velocity of the river 
accelerates towards the navigation channel, allowing the river to 
naturally scour the bed and provide stable areas for placement of 
dredged material. Existing pile dikes are semi-permeable groins 
consisting of two rows (riverine) or three rows (estuary) of untreated 
timber pilings driven on 2.5 foot centers. These timber piles are 
alternately placed on each side of horizontal spreader piles, which are 
bolted in place. Pile dikes in the FNC average about 400 ft with 
hundreds of pilings. Pile dike systems consist of a series of timber 
pile dikes, spaced about 1,200 to 1,500 ft apart for optimum functional 
efficiency. The outer dolphin, known as a king pile, is a taller bundle 
of piles marking the end of the pile dike for better visibility for 
users of the channel. The USACE has not built any new pile dikes since 
the construction of the 40-ft channel (approximately 1969), though some 
existing dikes have been repaired or rebuilt. Many pile dikes are 
presently in varying degrees of deterioration.
    Each pile structure will be composed of one or more piles. Proposed 
structures are slightly different from those typically found throughout 
the LCR. One main difference is that pile spacing within structures at 
confined aquatic placement sites needs to be smaller to slow river 
currents and prevent newly placed material from washing away. Because 
any pile structures would be buried to some degree by placed material, 
they include

[[Page 89546]]

only one row of piles that are not connected by a horizontal spreader.
    The design of each pile structure is tailored to the site 
conditions. For current planning purposes, the pile spacing is assumed 
to increase as you move from the shore toward the FNC over four 
segments:

 Shore to \1/3\ point of structure
 \1/3\ point to \1/2\ point of structure
 \1/2\ point to \3/4\ point of structure
 \3/4\ point to end of structure (enrockment only, no piles)

Steel marker pile at riverward end of structure.
    The pile spacing within the first three segments depends on whether 
piles are timber or steel. For planning purposes (subject to change 
during the design phase), all timber piles are assumed to be 12 inches 
(in) in diameter and all steel piles are assumed to be 24 in in 
diameter. These assumptions represent maximum pile widths, though 
smaller piles could ultimately be selected should more in-depth site 
assessments deem smaller pile widths acceptable. The permissible 
spacing for steel piles is twice the spacing of timber piles because 
the diameter of the steel piles is twice that of the timber piles. Both 
configurations would result in the same porosity.
    The decision on what type of piles should be used will be made on a 
site-by-site basis depending on the site conditions (e.g., water depth, 
currents, wave conditions, foundation conditions, etc.) along with the 
availability and cost of materials at the time of design and 
construction. Timber piles will most likely be installed in areas of 
shallow water with loose/soft to medium dense foundation. Steel piles 
will most likely be installed in deep water or in dense/hard 
foundations. The USACE has assumed that one-third of the piles will be 
timber and two-thirds will be steel. This conservative assumption 
ensures that sufficient numbers of steel piles and associated effects 
are accounted for should hard foundations be more prevalent. In the 
Application, the USACE noted that contractors expressed difficulties 
securing timber piles over the last 3-5 years. Therefore, this 
assumption also accounts for potential supply chain issues affecting 
the availability of timber pilings.
    Table 1 summarizes the spacing assumptions for potential pile 
structures used at confined aquatic placement sites. For the first \3/
4\ of each structure (from the shore), the bottom width of the 
enrockment is assumed to be 50 ft (based on a water depth of 30 ft). 
For the outer (riverward) \1/4\ of each structure, the bottom width of 
the enrockment increases to about 100 ft. The average width is about 65 
ft. However, for site W-35.6-IW-D, the two structures will be primarily 
rock with steel marker piles; the average bottom width is assumed to be 
100 ft.

    Table 1--Pile Spacing Assumptions for Timber and Steel Pipe Piles
------------------------------------------------------------------------
                                                       Pile spacing for
        Pile dike segment          Pile spacing for    24-in steel pipe
                                  12-in timber  (ft)         (ft)
------------------------------------------------------------------------
Shore to \1/3\ point of                          1.5                   3
 structure......................
\1/3\ point to \1/2\ point of                    2.5                   5
 structure......................
\1/2\ point to \3/4\ point of                      4                   8
 structure......................
------------------------------------------------------------------------

    For planning purposes and the calculations included in this LOA, it 
is assumed that one-third of the piles will be timber and two-thirds 
will be steel. Timber piles will most likely be installed in areas of 
shallow water with loose/soft to medium dense foundation. Steel piles 
will most likely be installed in deep water or in dense/hard 
foundations. This is a conservative assumption to ensure sufficient 
numbers of steel piles and associated effects are accounted for should 
hard foundations be more prevalent. Prior contractors have also 
expressed difficulties securing timber piles over the last 3-5 years. 
Thus, this assumption also accounts for potential supply chain issues 
affecting the availability of timber pilings. For a structure with a 
total length of L, the formulas for computing the number of piles are 
as follows:

 Timber piles number of piles = 0.351 x L
 Steel piles number of piles = 0.176 x L

    The total length of proposed structures is approximately 13,050 ft. 
However, excluding W-35.6-IW-D (only marker piles) and the 2 sites 
beyond the scope of this LOA (W-24.9-IW-S and O-26.7-IW-S) the total 
length for estimating the number of piles is 8,796 ft (table 2). Pile 
driving at the 2 out-of-scope locations is tentatively planned for 
2032/2033 and 2033/2034, beyond the effective period of these proposed 
regulations. The assumed length of timber pile structures to be 
installed under this LOA is 2,932 ft (i.e., one-third of the total 
length) and the assumed length of steel pile structures is 5,864 ft 
(i.e., two-thirds of the total length). Using the equations above, the 
anticipated total number of timber piles will be 1,029 and the total 
number of steel piles will be 1,032 plus 6 additional marker piles for 
site W-35.6-IW-D. These total numbers of piles are for the 5 placement 
sites that will require pile driving under this LOA (see table 2).

                            Table 2--Location and Properties of Proposed Pile Structures at Confined Aquatic Placement Sites
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                                                              Length of       Width of
               System name                 Structures  in     structure       structure              Material               Anticipated  LOA year(s)
                                               system           (ft)            (ft)
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O-23.5-BN-ADD2...........................               4           1,544          50-100  Piles and enrockment.......  Year 1.
W-35.6-IW-D..............................               2           1,555             100  Enrockment and 6 marker      Year 2.
                                                                                            piles.
O-23.5-BN-ADD1...........................               5           2,119          50-100  Piles and enrockment.......  Year 3.
O-27.3-BN................................               3           1,906          50-100  Piles and enrockment.......  Year 4.
O-31.4-BN................................               3           3,227          50-100  Piles and enrockment.......  Year 5.
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 89547]]

    Note that the lower parts of the piles will be surrounded by 
enrockment (also referred to as stone or riprap). The thickness of the 
enrockment will be about one-third of the water depth in terms of low 
water. The volume of enrockment will depend on the elevation profile of 
the riverbed along the structure alignment. NMFS, however, has 
determined that enrockment installation is not likely to result in 
harassment under the MMPA.
    Table 3 shows the locations, number and types of piles, as well as 
pile driving workdays anticipated to be required for the DMMP project 
spanning roughly 13 RM. These structures will support new confined 
aquatic placement sites in the LCR.

                       Table 3--In-Water Work, Pile Installation, and Workday Assumptions
----------------------------------------------------------------------------------------------------------------
                                                                                                    Anticipated
           In-water work location \1\              Timber  piles    Steel pipe     Total  piles    pile driving
                                                                       piles                       workdays \2\
----------------------------------------------------------------------------------------------------------------
                                         LOA YR-1 (Nov. 2027-Feb. 2028)
----------------------------------------------------------------------------------------------------------------
Enrockment placement and pile installation to                181             181             362              25
 construct 4 structures at Site O-23.5-BN-ADD2..
----------------------------------------------------------------------------------------------------------------
                                         LOA YR-2 (Nov. 2028-Feb. 2029)
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Construction of 2 new structures at Site W-35.6-              NA               6               6               1
   IW-D using enrockment and marker piles only
----------------------------------------------------------------------------------------------------------------
                                         LOA YR-3 (Nov. 2029-Feb. 2030)
----------------------------------------------------------------------------------------------------------------
Enrockment placement and pile installation to                248             249             497              34
 construct 5 structures at Site O-23.5-BN-ADD1..
----------------------------------------------------------------------------------------------------------------
                                         LOA YR-4 (Nov. 2030-Feb. 2031)
----------------------------------------------------------------------------------------------------------------
Enrockment placement and pile installation to                223             224             447              30
 construct 3 structures at Site O-27.3-BN.......
----------------------------------------------------------------------------------------------------------------
                                         LOA YR-5 (Nov. 2031-Feb. 2032)
----------------------------------------------------------------------------------------------------------------
Enrockment placement and pile installation to                377             379             756              51
 construct 3 structures at Site O-31.4-BN.......
----------------------------------------------------------------------------------------------------------------
    Total.......................................           1,029           1,038           2,068             141
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\1\ Reference system name that denotes the side of the channel (i.e., O for Oregon; W for Washington), river
  mile, type of placement (i.e., BN for beach nourishment; IW-S for in-water shallow; IW-D for in-water deeper
  than 20 ft).
\2\ Though up to 20 piles will be installed in a day, we estimate the total number of workdays based on an
  average of 15 piles being installed per day to account for potential delays due to equipment, weather, and
  other unforeseen circumstances.

    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (see Proposed Mitigation and 
Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the Application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs) (see https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS' 
website at: https://www.fisheries.noaa.gov/find-species.
    Table 4 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and the Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality 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 4 are 
the most recent available at the time of publication (including from 
the draft 2023 SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

[[Page 89548]]



                                    Table 4 -- Marine Mammal Species \1\ Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         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\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California Sea Lion.............  Zalophus californianus.  U.S....................  -,-, N              257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Steller Sea Lion................  Eumetopias jubatus.....  Eastern................  -, -, N             36,308 \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
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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: https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies.
\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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region.
  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.

    As indicated above, all 3 species (with 3 managed stocks) in table 
4 temporally and spatially co-occur with the activity to the degree 
that take is reasonably likely to occur.

California Sea Lion

    California sea lions are the most frequently sighted sea lion found 
in Washington waters and use haulout sites along the outer coast, the 
Strait of Juan de Fuca, and in the Puget Sound. The U.S. stock of 
California sea lions breeds on islands off the southern California 
coast. They are commonly found in Oregon haul-out sites from September 
to May and during this period, adult and subadult males have been 
observed in bays, estuaries, and offshore rocks along the Oregon coast. 
In fact, a few males have reported in Oregon waters throughout the year 
(Mate 1973). The population breeds in the California Channel Islands 
and most females and young pups remain in that region year-around 
(Mate, 1973; Oregon Department of Fish and Wildlife (ODFW), 2023). 
California sea lions may occur in the project vicinity and often use 
that same haulout sites as Steller sea lions (ODFW, 2023, see figure 4-
2 in the Application).

Steller Sea Lion

    Steller sea lions that occur in the LCR, including the project 
vicinity, are members of the eastern Distinct Population Segment (DPS), 
ranging from Southeast Alaska to central California, including 
Washington (Jeffries et al., 2000; Scordino, 2006; NMFS, 2013). Steller 
sea lions have been detected in the LCR and may occur in the vicinity 
of the project. All sea lions detected in the LCR are male and the 
nearest sea lion haulout sites are in Astoria and upriver near Rainier, 
Washington (USACE, 2024, see figure 4-2 in the Application). However, 
Steller sea lions will likely transit the Project Area during winter, 
depending on the timing of the eulachon spawning run which can attract 
large numbers of sea lions.

Harbor Seal

    Harbor seals are the most common widely-distributed marine mammal 
found in Washington marine waters and are frequently observed in the 
nearshore marine environment. They can commonly be found on offshore 
rocks and islands, along shores, and on exposed flats in the estuary 
(Harvey, 1987). Note that the Oregon/Washington Coastal Stock was most 
recently estimated at 24,732 harbor seals in 1999 and more recent 
abundance data is not available. There is no current estimate of 
abundance for this stock (Carretta et al., 2022).
    Harbor seals in this population are typically non-migratory and 
reside year-round in the LCR, and generally remain in the same area 
throughout the year for breeding and feeding. Harbor seals in the LCR 
do exhibit some seasonal movement upriver, including into or through 
the Project Area of ensonification, to follow winter and spring runs of 
Pacific eulachon (Thaleichthys pacificus) and out-migrating juvenile 
salmon (Oncorhynchus spp.), and they are observed regularly in portions 
of the LCR including the Project Area. Within the LCR, they tend to 
congregate to feed at the mouths of tributary rivers, including the 
Cowlitz and Kalama rivers (RMs 68 and 73, respectively). There are 
several known haul-out sites within 5 of the stretch of river (i.e., RM 
23 to RM 36) proposed for new pile driving (see figure 4-1 in the 
Application) and highest utilization of these lower river sights has 
typically been observed in May/June (Wright and Riemer, 2023).

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

[[Page 89549]]

lower bound from Southall et al. (2007) retained.
    On May 3, 2024, NMFS published and solicited public comment on its 
draft Updated Technical Guidance (89 FR 36762), which includes updated 
hearing ranges and names for the marine mammal hearing groups and is 
intended to replace the 2018 Technical Guidance once finalized. The 
public comment period ended on June 17th, 2024. Because NMFS may 
finalize the Guidance prior to taking a final agency action on this 
proposed rulemaking, we considered both the 2018 and 2024 Technical 
Guidance in our effects and estimated take analysis below. Marine 
mammal hearing groups and their associated hearing ranges from NMFS 
(2018) and NMFS (2024) are provided in tables 5 and 6. In the draft 
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 draft Updated Technical Guidance includes in-air data for phocid 
(PA) and otariid (OA) pinnipeds.

                  Table 5--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true   275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)    50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)   60 Hz to 39 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 are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).


                  Table 6--Marine Mammal Hearing Groups
                              [NMFS, 2024]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 36 kHz.
 whales).
High-frequency (HF) cetaceans         150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
Very High-frequency (VHF) cetaceans   200 Hz to 165 kHz.
 (true porpoises, Kogia, river
 dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L.
 australis).
Phocid pinnipeds (PW) (underwater)    40 Hz to 90 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)   60 Hz to 68 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges may not be as broad. Generalized hearing range
  chosen based on ~65 dB threshold from composite audiogram, previous
  analysis in NMFS 2018, and/or data from Southall et al. (2007);
  Southall et al. (2019). Additionally, animals are able to detect very
  loud sounds above and below that ``generalized'' hearing range.

    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018, 2024) for a review of available 
information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take of Marine Mammals section, and the Proposed Mitigation 
section, to draw conclusions regarding the likely impacts of these 
activities on the reproductive success or survivorship of individuals 
and whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far. The sound level of an area is defined by the 
total acoustical energy being generated by known and unknown sources. 
These sources may include physical (e.g., waves, wind, precipitation, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic sound 
(e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10 to 20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.

[[Page 89550]]

    In-water construction activities associated with the project would 
include vibratory pile removal, and impact and vibratory pile driving. 
The sounds produced by these activities fall into 1 of 2 general sound 
types: impulsive and non-impulsive. Impulsive sounds (e.g., explosions, 
gunshots, sonic booms, impact pile driving) are typically transient, 
brief (less than 1 second), broadband, and consist of high peak sound 
pressure with rapid rise time and rapid decay (American National 
Standards Institute (ANSI), 1986; National Institute for Occupational 
Safety and Health (NIOSH), 1998; ANSI, 2005; NMFS, 2018). Non-impulsive 
sounds (e.g., aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems) can be 
broadband, narrowband or tonal, brief or prolonged (continuous or 
intermittent), and typically do not have the high peak sound pressure 
with raid rise/decay time that impulsive sounds do (ANSI, 1995; NIOSH, 
1998; NMFS, 2018). The distinction between these two sound types is 
important because they have differing potential to cause physical 
effects, particularly with regard to hearing (e.g., Ward, 1997 in 
Southall et al., 2007).
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005). 
Vibratory hammers install piles by vibrating them and allowing the 
weight of the hammer to push them into the sediment. The vibrations 
produced also cause liquefaction of the substrate surrounding the pile, 
enabling the pile to be extracted or driven into the ground more 
easily. Vibratory hammers produce significantly less sound than impact 
hammers. Peak sound pressure levels (SPLs) may be 180 dB or greater but 
are generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards, 2002; Carlson et al., 2005).
    The likely or possible impacts of the USACE's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to be primarily acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving is the primary means by which marine 
mammals may be harassed from the proposed activity. In general, animals 
exposed to natural or anthropogenic sound may experience physical and 
psychological effects, ranging in magnitude from none to severe 
(Southall et al., 2007). In general, exposure to pile driving noise has 
the potential to result in an auditory threshold shift (TS) and 
behavioral reactions (e.g., avoidance, temporary cessation of foraging 
and vocalizing, changes in dive behavior). Exposure to anthropogenic 
noise can also lead to non-observable physiological responses, such as 
an increase in stress hormones. Additional noise in a marine mammal's 
habitat can mask acoustic cues used by marine mammals to carry out 
daily functions such as communication and predator and prey detection. 
The effects of pile driving noise on marine mammals are dependent on 
several factors, including, but not limited to, sound type (e.g., 
impulsive vs. non-impulsive), the species, age and sex class (e.g., 
adult male vs. mom with calf), duration of exposure, the distance 
between the pile and the animal, received levels, behavior at time of 
exposure, and previous history with exposure (Wartzok et al., 2004; 
Southall et al., 2007). Here we discuss physical auditory effects (TS) 
followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced TS as a change, usually an increase, 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018, 2024). The amount of TS is customarily expressed in 
dB. A TS can be permanent or temporary. As described in NMFS (2018, 
2024), there are numerous factors to consider when examining the 
consequence of TS, including, but not limited to, the signal temporal 
pattern (e.g., impulsive or non-impulsive), likelihood an individual 
would be exposed for a long enough duration or to a high enough level 
to induce a TS, the magnitude of the TS, time to recovery (seconds to 
minutes or hours to days), the frequency range of the exposure (i.e., 
spectral content), the hearing frequency range of the exposed species 
relative to the signal's frequency spectrum (i.e., how an animal uses 
sound within the frequency band of the signal; e.g., Kastelein et al., 
2014), and the overlap between the animal and the source (e.g., 
spatial, temporal, and spectral).
    Auditory Injury and Permanent Threshold Shift (PTS)--NMFS defines 
auditory injury as ``damage to the inner ear that can result in 
destruction of tissue . . . which may or may not result in PTS'' (NMFS, 
2024). NMFS defines PTS as a permanent, irreversible increase in the 
threshold of audibility at a specified frequency or portion of an 
individual's hearing range above a previously established reference 
level (NMFS, 2024). PTS does not generally affect more than a limited 
frequency range, and an animal that has incurred PTS has incurred some 
level of hearing loss at the relevant frequencies; typically, animals 
with PTS are not functionally deaf (Au and Hastings, 2008; Finneran, 
2016). Available data from humans and other terrestrial mammals 
indicate that a 40-dB threshold shift approximates PTS onset (see Ward 
et al., 1958, 1959, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et 
al., 1996; Henderson et al., 2008). PTS levels for marine mammals are 
estimates, as with the exception of a single study unintentionally 
inducing PTS in a harbor seal (Kastak et al., 2008), there are no 
empirical data measuring PTS in marine mammals largely due to the fact 
that, for various ethical reasons, experiments involving anthropogenic 
noise exposure at levels inducing PTS are not typically pursued or 
authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS)--TTS is a temporary, reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level (NMFS, 2018). Based on data from cetacean TTS 
measurements (Southall et al., 2007, 2019), a TTS of 6 dB is considered 
the minimum TS clearly larger than any day-to-day or session-to-session 
variation in a subject's normal hearing ability (Schlundt et al., 2000; 
Finneran et al., 2000, 2002). As described in Finneran (2015), marine 
mammal studies have shown the amount of TTS increases with cumulative 
sound exposure level (SELcum) in an accelerating fashion: At 
low exposures with lower SELcum, the amount of TTS is 
typically small and the growth curves have shallow slopes. At exposures 
with higher SELcum, the growth curves become steeper and 
approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and

[[Page 89551]]

the context in which it is experienced, TTS can have effects on marine 
mammals ranging from discountable to serious (similar to those 
discussed in auditory masking, below). For example, a marine mammal may 
be able to readily compensate for a brief, relatively small amount of 
TTS in a non-critical frequency range that takes place during a time 
when the animal is traveling through the open ocean, where ambient 
noise is lower and there are not as many competing sounds present. 
Alternatively, a larger amount and longer duration of TTS sustained 
during a time when communication is critical for successful mother/calf 
interactions could have more serious impacts. We note that reduced 
hearing sensitivity as a simple function of aging has been observed in 
marine mammals, as well as humans and other taxa (Southall et al., 
2007), so we can infer that strategies exist for coping with this 
condition to some degree, though likely not without cost.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. For 
pinnipeds in water, measurements of TTS are limited to harbor seals, 
elephant seals (Mirounga angustirostris), bearded seals (Erignathus 
barbatus) and California sea lions (Kastak et al., 1999, 2007; 
Kastelein et al., 2019b, 2019c, 2021, 2022a, 2022b; Reichmuth et al., 
2019; Sills et al., 2020). These studies examined hearing thresholds 
measured in marine mammals before and after exposure to intense or 
long-duration sound exposures. The difference between the pre-exposure 
and post-exposure thresholds can be used to determine the amount of TS 
at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor 
seals have a lower TTS onset than other measured pinniped species 
(Finneran, 2015). In addition, TTS can accumulate across multiple 
exposures, but the resulting TTS will be less than the TTS from a 
single, continuous exposure with the same SEL (Mooney et al., 2009; 
Finneran et al., 2010; Kastelein et al., 2014, 2015). This means that 
TTS predictions based on the total, SELcum will overestimate 
the amount of TTS from intermittent exposures, such as sonars and 
impulsive sources. Nachtigall et al. (2018) describes measurements of 
hearing sensitivity of multiple odontocete species (i.e., bottlenose 
dolphin, harbor porpoise, beluga, and false killer whale (Pseudorca 
crassidens)) when a relatively loud sound was preceded by a warning 
sound. These captive animals were shown to reduce hearing sensitivity 
when warned of an impending intense sound. Based on these experimental 
observations of captive animals, the authors suggest that wild animals 
may dampen their hearing during prolonged exposures or if conditioned 
to anticipate intense sounds. Additionally, the existing marine mammal 
TTS data come from a limited number of individuals within these 
species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but such relationships are assumed to be similar to 
those in humans and other terrestrial mammals. PTS typically occurs at 
exposure levels at least several dBs above that inducing mild TTS 
(e.g., a 40-dB TS approximates PTS onset (Kryter et al., 1966; Miller, 
1974), while a 6-dB TS approximates TTS onset (Southall et al., 2007, 
2019). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulsive sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS SELcum thresholds are 15 to 20 dB higher than TTS 
SELcum thresholds (Southall et al., 2007, 2019). Given the 
higher level of sound or longer exposure duration necessary to cause 
PTS as compared with TTS, it is considerably less likely that PTS could 
occur.
    Installing piles for this project requires either impact pile 
driving or vibratory pile driving. For this project, these activities 
would not occur at the same time, and there would be pauses in 
activities producing the sound during each day. Given these pauses, and 
that many marine mammals are likely moving through the ensonified area 
and not remaining for extended periods of time, the potential for TS 
declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
Available studies show wide variation in response to underwater sound; 
therefore, it is difficult to predict specifically how any given sound 
in a particular instance might affect marine mammals perceiving the 
signal. If a marine mammal does react briefly to an underwater sound by 
changing its behavior or moving a small distance, the impacts of the 
change are unlikely to be significant to the individual, let alone the 
stock or population. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on individuals and populations could be significant 
(e.g., Lusseau and Bejder, 2007; Weilgart, 2007; National Research 
Council (NRC), 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (e.g., socializing or feeding); visible startle 
response or aggressive behavior (e.g., tail/fluke slapping or jaw 
clapping); or avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006).
    Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic 
factors (e.g., species, state of maturity, experience, current 
activity, reproductive state, auditory sensitivity, time of day), as 
well as the interplay between factors (e.g., Richardson et al., 1995; 
Wartzok et al., 2003; Southall et al., 2007; Weilgart, 2007; Archer et 
al., 2010). Behavioral reactions can vary not only among individuals 
but also within an individual, depending on previous experience with a 
sound source, context, and numerous other factors (Ellison et al., 
2012), and can vary depending on characteristics associated with the 
sound source (e.g., whether it is moving or stationary, number of 
sources, distance from the source). In general, pinnipeds seem more 
tolerant of, or at least habituate more quickly to, potentially 
disturbing underwater sound than do cetaceans, and generally seem to be 
less responsive to exposure to

[[Page 89552]]

industrial sound than most cetaceans. Please see appendices B-C of 
Southall et al. (2007) and Gomez et al. (2016) for a review of studies 
involving marine mammal behavioral responses to sound.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity and may occur 
whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g., on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked.
    Airborne Acoustic Effects--Although pinnipeds are known to haul out 
regularly on manmade objects, we believe that incidents of take 
resulting solely from airborne sound are unlikely because there are no 
known haulouts within the immediate project vicinity on the LCR. There 
is a possibility that an animal could surface in-water, but with head 
out, within the area in which airborne sound exceeds relevant 
thresholds and thereby be exposed to levels of airborne sound that we 
associate with harassment, but any such occurrence would likely be 
accounted for in our estimation of incidental take from underwater 
sound. Therefore, authorization of incidental take resulting from 
airborne sound for pinnipeds is not warranted, and airborne sound is 
not discussed further here.

Marine Mammal Habitat Effects

    The USACE's construction activities could have localized, temporary 
impacts on marine mammal habitat by increasing in-water SPLs and 
slightly decreasing water quality. No net habitat loss is expected, as 
the dock will be reconstructed within its original footprint. 
Construction activities are localized and would likely have temporary 
impacts on marine mammal habitat through increases in underwater 
sounds. Increased noise levels may affect acoustic habitat (see masking 
discussion above) and adversely affect marine mammal prey in the 
vicinity of the Project Area (see discussion below). During pile 
driving activities, elevated levels of underwater noise would ensonify 
the Project Area where both fishes and marine mammals may occur and 
could affect foraging success. Additionally, marine mammals may avoid 
the area during construction; however, displacement due to noise is 
expected to be temporary and is not

[[Page 89553]]

expected to result in long-term effects to the individuals or 
populations.
    Temporary and localized reduction in water quality would occur 
because of in-water construction activities as well. Most of this 
effect would occur during the installation and removal of piles when 
bottom sediments are disturbed. The installation of piles would disturb 
bottom sediments and may cause a temporary increase in suspended 
sediment in the Project Area. In general, turbidity associated with 
pile installation is localized to about 25-ft (7.6-m) radius around the 
pile (Everitt et al., 1980). Pinnipeds are not expected to be close 
enough to the pile driving areas to experience effects of turbidity and 
could avoid localized areas of turbidity. Therefore, we expect the 
impact from increased turbidity levels to be discountable to marine 
mammals and do not discuss it further.

In-Water Construction Effects on Potential Foraging Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals. The total riverbed area 
affected by pile installation and removal is a very small area compared 
to the vast foraging area available to marine mammals in the LCR and 
Washington's outer coast and contains no habitat areas of particular 
importance. Pile installation may have impacts on benthic invertebrate 
species primarily associated with disturbance of sediments that may 
cover or displace some invertebrates. The impacts would be temporary 
and highly localized, and no habitat would be permanently displaced by 
construction. Therefore, it is not expected to have impacts on foraging 
opportunities for marine mammals.
    It is possible that avoidance by potential prey (i.e., fish) in the 
immediate area may occur due to temporary loss of this foraging 
habitat. The duration of fish avoidance of this area after pile driving 
stops is unknown, but we anticipate a rapid return to normal 
recruitment, distribution and behavior. Any behavioral avoidance by 
fish of the disturbed area would still leave large areas of fish and 
marine mammal foraging habitat in the nearby vicinity in the in the 
Project Area and LCR.

Effects on Potential Prey

    Sound may affect marine mammals through impacts on the abundance, 
behavior, or distribution of prey species (i.e., fish). Marine mammal 
prey varies by species, season, and location. Here, we describe studies 
regarding the effects of noise on known marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fish hear sounds using pressure and particle 
motion sensitivity capabilities and detect the motion of surrounding 
water (Fay et al., 2008). The potential effects of noise on fish 
depends on the overlapping frequency range, distance from the sound 
source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fish may include 
behavioral responses, hearing damage, barotrauma (i.e., pressure-
related injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses, such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009). Several studies have demonstrated that impulse sounds might 
affect the distribution and behavior of some fishes, potentially 
impacting foraging opportunities or increasing energetic costs (e.g., 
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al., 
1992; Santulli et al., 1999; Paxton et al., 2017). However, some 
studies have shown no or slight reaction to impulse sounds (e.g., Pena 
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott 
et al., 2012).
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality (summarized in Popper et al., 2014). However, in 
most fish species, hair cells in the ear continuously regenerate and 
loss of auditory function likely is restored when damaged cells are 
replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of 
4 to 6 dB was recoverable within 24 hours for one species. Impacts 
would be most severe when the individual fish is close to the source 
and when the duration of exposure is long. Injury caused by barotrauma 
can range from slight to severe and can cause death and is most likely 
for fish with swim bladders. Barotrauma injuries have been documented 
during controlled exposure to impact pile driving (Halvorsen et al., 
2012a; Casper et al., 2013, 2017).
    Fish populations in the proposed Project Area that serve as marine 
mammal prey could be temporarily affected by noise from pile 
installation and removal. The frequency range in which fishes generally 
perceive underwater sounds is 50 to 2,000 Hertz (Hz), with peak 
sensitivities below 800 Hz (Popper and Hastings, 2009). Fish behavior 
or distribution may change, especially with strong and/or intermittent 
sounds that could harm fishes. High underwater SPLs have been 
documented to alter behavior, cause hearing loss, and injure or kill 
individual fish by causing serious internal injury (Hastings and 
Popper, 2005).
    The greatest potential impact to fishes during construction would 
occur during impact pile driving. However, the duration of impact pile 
driving would be limited to the final stage of installation 
(``proofing'') after the pile has been driven as close as practicable 
to the design depth with a vibratory driver. In-water construction 
activities would only occur during daylight hours, allowing fish to 
forage and transit the Project Area in the evening. Vibratory pile 
driving could elicit behavioral reactions from fishes such as temporary 
avoidance of the area but is unlikely to cause injuries to fishes or 
have persistent effects on local fish populations. Additionally, all 
pile installation would occur only during the USACE's and United States 
Fish and Wildlife Service designated in-water work window to minimize 
potential exposure of ESA-listed fish species migrating through the 
project site to noise from impact pile driving. Construction also would 
have minimal permanent and temporary impacts on benthic invertebrate 
species, a marine mammal prey source.
    The area impacted by the project is relatively small compared to 
the available habitat in the remainder of the LCR, and there are no 
areas of particular importance that would be impacted by this project. 
Any behavioral avoidance by fish of the disturbed area would still 
leave significantly large areas of fish and marine mammal foraging 
habitat in the nearby vicinity. As described in the preceding, the 
potential for the USACE's construction to affect the availability of

[[Page 89554]]

prey to marine mammals or to meaningfully impact the quality of 
physical or acoustic habitat is considered to be insignificant.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this proposed rule, which will 
inform NMFS' consideration of ``small numbers,'' the negligible impact 
determinations, and impacts on subsistence uses.
    Harassment, defined previously in the Purpose and Need for 
Regulatory Action section, is the only type of take expected to result 
from these activities.
    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 proposed mitigation and monitoring measures are 
expected to minimize the severity of the taking to the extent 
practicable.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. We describe 
how the proposed take numbers are estimated below.
    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 proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile 
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals (e.g., 
conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    The USACE's proposed activity includes the use of continuous 
(vibratory pile driving) and impulsive (impact pile driving) sources, 
and therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are 
applicable.
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; 
NMFS, 2018) and the draft Updated Technical Guidance (NMFS, 2024) 
identify 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). This proposed rule estimates Level A 
harassment using the existing Technical Guidance (NMFS, 2018) as well 
as the draft Updated Technical Guidance (NMFS, 2024) because at the 
time of the final agency decision on this request for incidental take, 
it's possible NMFS may have made a final agency decision on the draft 
Guidance.
    These thresholds are provided in tables 7 and 8 below. The 
references, analysis, and methodology used in the development of the 
thresholds are described in NMFS' 2018 Technical Guidance and NMFS' 
2024 draft Updated Technical Guidance, both of which may be accessed 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    The USACE's proposed activity includes the use of impulsive (impact 
pile driving) and non-impulsive (vibratory driving) sources.

             Table 7--NMFS' 2018 Thresholds Identifying the Onset of Permanent Threshold Shift (PTS)
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                 Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;  Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;  Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;  Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;  Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.

[[Page 89555]]

 
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;  Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak SPL 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 SELcum 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 SELcum 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 SELcum 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.


                Table 8--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, HF,24h: 201 dB.
                                          dB; LE,p, HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans....  Cell 5: L0-pk,flat: 202    Cell 6: LE, VHF,24h: 181 dB.
                                          dB; LE,p,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: L0-pk.flat: 223    Cell 8: LE,PW,24h: 195 dB.
                                          dB; LE,p,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: L0-pk,flat: 230    Cell 10: LE,OW,24h: 199 dB.
                                          dB; LE,p,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,p,PA,24h: 140 dB.
Otariid Pinnipeds (OA) (In-Air)........  Cell 13: L0-pk,flat: 177   Cell 14: LE,OA,24h: 177 dB.
                                          dB; LE,p,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 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 proposed project. 
Pile driving generates underwater noise that can potentially result in 
disturbance to marine mammals in the Project Area. The maximum 
(underwater) area ensonified is determined by the topography of the 
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 Log10 (R1/R2)

Where:
TL = transmission loss in dB;
B = transmission loss coefficient; for practical spreading equals 
15;
R1 = the distance of the modeled SPL from the driven 
pile; and,
R2 = the distance from the driven pile of the initial 
measurement.
    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6-dB reduction in sound level for each doubling of 
distance from the source (20xlog10[range]). Cylindrical 
spreading occurs in an environment in which sound propagation is 
bounded by the water surface and sea bottom, resulting in a reduction 
of 3 dB in sound level for each doubling of distance from the source 
(10xlog10[range]). A practical spreading value of 15 is 
often used

[[Page 89556]]

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 9). Generally, we choose source levels from similar pile types 
from locations (e.g., geology, bathymetry) similar to the project.

                      Table 9--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 10 below. The calculated Level A and Level B harassment 
isopleths are shown in table 11 and table 12.

                                     Table 10--NMFS User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
                                                              Weighting                 Duration to
                                                               factor      Number of      drive a     Number of
         Pile size and type           Spreadsheet tab used   adjustment    piles per    single pile  strikes per
                                                                (kHz)         day          (min)         pile
----------------------------------------------------------------------------------------------------------------
                                       Vibratory pile driving and removal
----------------------------------------------------------------------------------------------------------------
24-in steel pile (Vibratory).......  A.1) Vibratory pile             2.5           20            25           NA
                                      driving.
12-in Timber (Vibratory)...........  A.1) Vibratory pile             2.5           20            25           NA
                                      driving.
----------------------------------------------------------------------------------------------------------------
                                               Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile (Impact             E.1) Impact pile                  2           20            NA           45
 attenuated).                         driving.
12-in Timber (Impact attenuated)...  E.1) Impact pile                  2           20            NA           45
                                      driving.
----------------------------------------------------------------------------------------------------------------


Table 11--Calculated Distance of Level A (Based on NMFS' 2018 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................................................           12.63             0.9         3,981.1
12-in timber pile...............................................            19.9             1.4         6,309.6
----------------------------------------------------------------------------------------------------------------
                                               Impact pile driving
----------------------------------------------------------------------------------------------------------------
24-in steel pile................................................            79.0             5.7           464.2
12-in timber pile...............................................             6.8             0.5            21.5
----------------------------------------------------------------------------------------------------------------


[[Page 89557]]


  Table 12--Calculated Distance of Level A (Based on NMFS' Proposed 2024 Update to the 2018 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
----------------------------------------------------------------------------------------------------------------
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 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 proposed for authorization. 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. While the 
confluence of the two rivers is located approximately 31.5 river miles 
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 proposed 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- of 
proposed 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 13 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 
(figure 6-21 in the Application). The hatched area in the figure is 
roughly 377 square kilometers (km\2\) which yielded an approximate 
daily harbor seal density of 5 individuals per km\2\ in the Project 
Area. 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 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.

[[Page 89558]]



    Table 13--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]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                 South                 Desdemona    Taylor                  Miller       Green    N of Woody
                    Month                        Jetty     Baker Bay     Sands       Sands     Grays Bay     Sands      Island      Island       Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
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
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 14. These inputs were used in the 
equation above to estimate the number of harbor seals possible within 
those isopleths each day (table 15) and then calculate the overall 
level of take based on the number of workdays projected in each year 
(table 16). 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 
16. NMFS concurs with this assessment and is proposing to authorize 
harbor seal take according to the totals contained in table 16.

                             Table 14--Pile Dike Lengths (m) and Corresponding Level A and Level B Harassment Areas (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            All Marine
                                                                                     Phocids level A      All Marine       All Marine    Mammals level B
                    Site                              Pile dike length (m)            (km\2\) 24-in    Mammals level B  Mammals level B   (km\2\) 12-in
                                                                                       Steel Impact     (km\2\) 24-in    (km\2\) 24-in        timber
                                                                                                         steel impact   steel 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 15--Estimated Harbor Seals in Level A and Level B Harassment Zones per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        HS in Level B    HS in Level B    HS in Level B
                                                                                     HS * in Level A    isopleth area    isopleth area    isopleth area
                    Site                             Installation timeframe         isopleth area 24-    24-in steel      24-in steel      12-in timber
                                                                                     in steel 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 16--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
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
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 89559]]

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 17. 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 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 to RM 36) compared to the Rainer (RM 
67) and Coffin Rock (RM 72) locations. Based on counts of sea lions at 
the EMB site (table 17), 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 proposed (15-20 
m) for all pile driving scenarios as shown in table 12, and no such 
take is proposed for authorization.

Table 17--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 18:

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 18--Proposed Take by Level B Harassment for California and Steller Sea Lions Likely To Be in the Project
                                                    Vicinity
----------------------------------------------------------------------------------------------------------------
                                                 Total pile driving    Level B harassment    Level B harassment
                                                      Workdays                 CSL                   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 proposed for authorization by NMFS are shown 
in table 19.

[[Page 89560]]



                                                   Table 19--Proposed Takes by Level A Harassment and Level B Harassment Annually Over 5 Years
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Yr 1                  Yr 2                  Yr 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 89561]]

    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 1 year for each species to 
yield the highest number of estimated take that could occur in any year 
(table 20). Table 20 also depicts the number of takes proposed relative 
to the abundance of each stock.

  Table 20--Maximum Number of Proposed 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).

Proposed Mitigation

    Under section 101(a)(5)(D) of the MMPA, NMFS must set forth the 
permissible methods of taking pursuant to the activity, and other means 
of effecting the least practicable impact on the species or stock and 
its habitat, paying particular attention to rookeries, mating grounds, 
and areas of similar significance, and on the availability of the 
species or stock for taking for certain subsistence uses (latter not 
applicable for this action). NMFS regulations require applicants for 
incidental take authorizations to include information about the 
availability and feasibility (economic and technological) of equipment, 
methods, and manner of conducting the activity or other means of 
effecting the least practicable adverse impact upon the affected 
species or stocks, and their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers 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 
implemented as planned); and
    2. The practicability of the measures for applicant implementation, 
which may consider such things as cost, impact on operations.
    The mitigation measures described in the following sections would 
apply to the USACE in-water construction activities.

Proposed Shutdown and Monitoring Zones

    In most impact and pile driving scenarios, the proposed shutdown 
zones exceed the calculated Level A isopleths; an exception occurs 
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 proposed shutdown zone of 50 m. 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. Therefore, 
the shutdown zone will be established at 50 m for phocid pinnipeds 
during impact driving of 24-in steel piles.

                    Table 21--Proposed Shutdown Zone 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
----------------------------------------------------------------------------------------------------------------

    Prior to pile driving, protected species observers (PSOs) would 
survey the shutdown zones shown in table 21 and surrounding areas for 
at least 30 minutes before pile driving activities start. If marine 
mammals are found

[[Page 89562]]

within the shutdown zone, pile driving would 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 would 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 would 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 would 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 would 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 would 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 Proposed 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 would observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone would 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 would be delayed or halted. 
If work ceases for more than 30 minutes, the pre-activity monitoring of 
the shutdown zones would 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 proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to 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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving, or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring during pile driving and removal must be 
conducted by NMFS-approved PSOs in a manner consistent with the 
following:
     PSOs must be independent of the activity contractor (e.g., 
employed by a subcontractor) and have no other assigned tasks during 
monitoring periods;
     At least 1 PSO must have prior experience performing the 
duties of a PSO during construction activity pursuant to a NMFS-issued 
incidental take authorization;
     Other PSOs may substitute 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.

[[Page 89563]]

     Where a team of 3 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.
     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 should have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to: (1) the number and species 
of marine mammals observed; (2) dates and times when in-water 
construction activities were conducted; (3) dates, times, and reason 
for implementation of mitigation (or why mitigation was not implemented 
when required); and (4) marine mammal behavior; and
     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 2 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 would be stationed along the shore of the LCR. One would 
be located on the closest shoreline or construction barge adjacent to 
proposed 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 would ensure that construction supervisors and crews, the 
monitoring team, and relevant USACE staff are trained prior to the 
start of activities subject to the proposed LOA, so that 
responsibilities, communication procedures, monitoring protocols, and 
operational procedures are clearly understood. New personnel joining 
during the project would be trained prior to commencing work. 
Monitoring would occur for all in-water pile driving activities during 
the pile installation work window (November 1 to February 15).

Data Collection

    PSOs would use approved data forms to record the following 
information:
     Dates and times (beginning and end) of all marine mammal 
monitoring;
     PSO locations during marine mammal monitoring;
     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);
     Weather parameters and water conditions;
     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;
     Distance and bearings of each marine mammal observed to 
the pile being driven or removed;
     Description of marine mammal behavior patterns, including 
direction of travel;
     Age and sex class, if possible, of all marine mammals 
observed; and
     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:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     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;
     PSO locations during marine mammal monitoring;
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
     Upon observation of a marine mammal, the following 
information: (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);
     Number of marine mammals detected within the harassment 
zones, by species; and
     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.
    If no comments are received from NMFS within 30 days, the draft 
final report would constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover

[[Page 89564]]

an injured or dead marine mammal, the USACE shall report the incident 
to the Office of Protected Resources (OPR), 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:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to 
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.
    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 proposed mitigation 
measures (see Proposed 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 proposed to be 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 proposed 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 be taken by Level A 
harassment. Limited take by Level A harassment is expected to arise 
from, at most, a small degree of auditory injury (AUD INJ) during 
impact driving, which will only be used briefly to achieve the final 5-
ft 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 AUD INJ. Additionally, and as noted 
previously, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. Because of the small degree anticipated, 
though, any AUD INJ or TTS potentially incurred here 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 15 each 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 
proposed 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 preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of

[[Page 89565]]

the species or stocks through effects on annual rates of recruitment or 
survival:
     No serious injury or mortality is anticipated or 
authorized;
     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;
     No important habitat areas have been identified within the 
Project Area;
     For species proposed for authorization, the Project Area 
is a very small and peripheral part of their range and anticipated 
habitat impacts are minor;
     The USACE would implement mitigation measures, such as 
bubble curtains and soft-starts for impact pile driving; and
     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 AUD 
INJ.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under 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. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    Table 20 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 proposed 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 proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Adaptive Management

    The regulations governing the take of marine mammals incidental to 
the USACE's construction activities would contain an adaptive 
management component. The reporting requirements associated with this 
proposed 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 
to 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.

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 proposed rules, NMFS consults 
internally whenever we propose to authorize take for endangered or 
threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Request for Information

    NMFS requests interested persons to submit comments, information, 
and suggestions concerning the USACE's request and the proposed 
regulations (see ADDRESSES). All comments germane to this rulemaking 
will be reviewed and evaluated as we prepare a final rule and make 
final determinations on whether to issue the requested authorization. 
This proposed rule and referenced documents provide all environmental 
information relating to our proposed action for public review.

Classification

    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.
    Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA), 
the Chief Counsel for Regulation of the Department of Commerce has 
certified to the Chief Counsel for Advocacy of the Small Business 
Administration that this proposed rule, if adopted, would not have a 
significant economic impact on a substantial number of small entities. 
The USACE is the sole entity that would be subject to the requirements 
in these proposed regulations, and the USACE is not a small 
governmental jurisdiction, small organization, or small business, as 
defined by the RFA. Therefore, a regulatory flexibility analysis is not 
required and none has been prepared.
    This proposed rule does not contain a collection-of-information 
requirement subject to the provisions of the Paperwork Reduction Act 
(PRA) because the applicant is a Federal agency.

List of Subjects in 50 CFR Part 217

    Administrative practice and procedure, Exports, Fish, Imports,

[[Page 89566]]

Marine mammals, Penalties, Reporting and recordkeeping requirements, 
Transportation, Wildlife.

    Dated: November 4, 2024.
Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.

    For the reasons set forth in the preamble, NMFS proposes to amend 
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 activities on its behalf for the taking of marine 
mammals that occur in the areas outlined in paragraph (b) of this 
section and that occur incidental to construction activities, including 
maintenance and replacement of piles, as designated in the Lower 
Columbia River Dredged Material Management Plan, Oregon and Washington. 
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.

    Except for the takings contemplated in Sec.  217.72 and authorized 
by an LOA issued under this subpart, 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 an LOA issued under this subpart;
    (2) Take of 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 if 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.


Sec.  217.74   Mitigation requirements.

    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 between supervisors and crews, 
the PSO team, and relevant USACE staff are trained prior to the start 
of construction activity subject to this subpart, 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 (see Sec.  217.75). 
The USACE must monitor the project area 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 observation when 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 an 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 paragraph (a)(9) of this 
section.
    (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 beyond the 
shutdown zone or 15 minutes have passed without re-detection of the 
animal.
    (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 impact pile driving and at any time following cessation of impact 
pile driving for a period of 30 minutes or longer.

[[Page 89567]]

    (11) The USACE must deploy PSOs as indicated in an NMFS-approved 
Marine Mammal Monitoring Plan.
    (12) The USACE must employ bubble curtain systems during all impact 
driving except under conditions 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.
    (13) 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.
    (14) Pile driving activity must be halted upon observation of 
either a species for which incidental take is not authorized or a 
species for which incidental take has been authorized but the 
authorized number of takes has been met, entering or within the 
harassment zone.


Sec.  217.75   Requirements for monitoring and reporting.

    (a) The USACE must submit a Marine Mammal 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 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.
    (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. 
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 reports must contain the informational elements described 
in paragraphs (d)(1) through (5) of this section at minimum:
    (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), 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); and
    (5) Upon observation of a marine mammal, the following information 
should be collected:
    (i) PSO who sighted the animal, observer location, and activity at 
time of sighting:
    (ii) Time of sighting;
    (iii) Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
    (iv) Distances and bearings of each marine mammal observed in 
relation to the pile being driven for each sighting (if pile driving 
was occurring at time of sighting);
    (v) Estimated number of animals (min/max/best);
    (vi) Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
    (vii) Animal's closest point of approach and estimated time spent 
within the harassment zone;
    (viii) Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses to the activity (e.g., no response 
or changes in behavioral state such as ceasing feeding, changing 
direction, flushing, or breaching);
    (ix) 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 subpart and the LOA issued under Sec.  216.106 of this chapter 
and Sec. 217.76. The USACE must not resume their activities until 
notified by NMFS. The report must include the following information:

[[Page 89568]]

    (1) Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    (2) Species identification (if known) or description of the 
animal(s) involved;
    (3) Condition of the animal(s) (including carcass condition if the 
animal is dead);
    (4) Observed behaviors of the animal(s), if alive;
    (5) If available, photographs or video footage of the animal(s); 
and
    (6) General circumstances under which the animal was discovered.


Sec.  217.76   Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to this subpart, 
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 February 29, 2032.
    (c) If an LOA expires prior to February 29, 2032, 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 this subpart.
    (g) Notice of issuance or denial of an LOA must be published in the 
Federal Register within 30 days of a determination.


Sec.  217.77   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 proposed specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for this subpart; and
    (2) NMFS determines that the mitigation, monitoring, and reporting 
measures required by the previous LOA under this subpart 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 for this subpart or 
result in no more than a minor change in the total estimated number of 
takes (or distribution by species or years), NMFS may publish a notice 
of proposed LOA in the Federal Register, including the associated 
analysis of the change, and solicit public comment before issuing the 
LOA.
    (c) 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 this subpart;
    (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 this subpart 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; and
    (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 an LOA issued pursuant to Sec.  216.106 of this 
chapter and Sec.  217.76, an 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. 2024-26069 Filed 11-12-24; 8:45 am]
BILLING CODE 3510-22-P