Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to National Oceanic and Atmospheric Administration Office of Marine and Aviation Operations Research Vessel Relocation at Naval Station Newport, Rhode Island, 78072-78087 [2022-27727]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 87, Number 244 (Wednesday, December 21, 2022)]
[Notices]
[Pages 78072-78087]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-27727]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC528]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to National Oceanic and Atmospheric 
Administration Office of Marine and Aviation Operations Research Vessel 
Relocation at Naval Station Newport, Rhode Island

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
NOAA Office of Marine Aviation Operations (OMAO) to incidentally 
harass, by Level A and Level B harassment, marine mammals during 
construction activities associated with vessel relocation at Naval 
Station Newport (NAVSTA) in Newport, Rhode Island.

DATES: This authorization is effective from February 1, 2024 to January 
31, 2025.

FOR FURTHER INFORMATION CONTACT: Jessica Taylor, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed incidental harassment authorization is provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

Summary of Request

    On May 6, 2022, NMFS received a request from the U.S. Navy on 
behalf of OMAO for an IHA to take marine mammals incidental to 
construction activities associated with the relocation of NOAA research 
vessels to the Naval Station Newport in Rhode Island. NMFS reviewed the 
Navy's application and the Navy provided a revised application on July 
14, 2022. The application was deemed adequate and complete on October 
5, 2022. OMAO's request is for take of 7 species of marine mammals, by 
Level B harassment and, for a subset of these species, Level A 
harassment. Neither OMAO nor NMFS expect serious injury or mortality to 
result from this activity and, therefore, an IHA is appropriate. OMAO 
plans to commence in-water construction activities on February 1, 2024 
yet has requested the IHA in advance due to OMAO's NEPA requirements.

Description of Activity

    OMAO plans to establish adequate pier, shore side, and support 
facilities for four NOAA research vessels in Coddington Cove at Naval 
Station (NAVSTA) Newport in Newport, Rhode Island. As part of the 
activity, a new pier, trestle, small boat floating dock, and bulkhead 
will be constructed in Coddington Cove in order to meet NOAA docking/
berthing requirements for these four vessels. These construction 
activities will involve the use of impact and vibratory pile driving, 
vibratory pile extraction, rotary drilling, and down-the-hole (DTH) 
mono-hammer excavation events, which have the potential to take marine 
mammals, by Level A and Level B harassment. The project will also 
include shore side administrative, warehouse, and other support 
facilities.
    Construction activities will last for approximately one year from 
February 1, 2024 to January 31, 2025 of which in-water work will take 
place over 343 non-consecutive days. OMAO anticipates that all work 
will be limited to daylight hours. Specific construction activities may 
occur concurrently over a period of approximately 138 days. A detailed 
description of the planned construction project is provided in the 
Federal Register notice for the proposed IHA (87 FR 66133, November 2, 
2022). Since that time, no changes have been made to the planned 
activities. Therefore, a detailed description is not provided here. 
Please refer to that Federal Register notice for the description of the 
specific activity. Mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Mitigation and 
Monitoring and Reporting).

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to OMAO was published in 
the Federal Register on November 2, 2022 (87 FR 66133). That notice 
described, in detail, OMAO's activity, the marine mammal species that 
may be affected by the activity, and the anticipated effects on marine 
mammals. During the 30-day public comment period, no public comments 
were received.

Changes From the Proposed to Final IHA

    Two changes were made between publication of the proposed IHA and 
this final IHA. The Level B harassment

[[Page 78073]]

zone for the vibratory extraction of 12'' timber guide piles while 
demolishing the floating dock was changed from 3,500 m to 1,359 m. The 
original calculated distance of 3,500 m was an error. However, PSOs 
will monitor as far as they can see.
    In addition, the final IHA requires OMAO to wait 15 minutes before 
commencing pile driving activity after a shutdown, rather than 30 
minutes as stated in the proposed IHA. This change is consistent with 
monitoring methods for prior projects consisting of similar 
construction activities at NAVSTA Newport, RI (86 FR 71162, December 
15, 2021) and other locations (87 FR 7128, February 2, 2022; 87 FR 
19886, April 6, 2022).

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, referenced here, instead of reprinting the 
information. Additional information regarding population trends and 
threats may be found in NMFS' Stock Assessment Reports (SARs; 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS' 
website (https://www.fisheries.noaa.gov/find-species.)
    Table 1 lists all species or stocks for which take is authorized 
for these activities, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is defined by the MMPA as the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population (as described in NMFS' SARs). While no 
serious injury or mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species 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 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. 
Atlantic and Gulf of Mexico SARs (e.g., Hayes et al., 2022). All values 
presented in Table 1 are the most recent available at the time of 
publication (available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                     Table 1--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\
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                              Order Artiodactyla--Infraorder Cetacea--Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Atlantic white-sided dolphins...  Lagenorhynchus acutus..  Western North Atlantic.  -, -, N             93,233 (0.71, 54,443,         544         27
                                                                                                             2016).
    Common dolphins.................  Delphinus delphis......  Western North Atlantic.  -, -, N             172,974 (0.21,              1,452        390
                                                                                                             145,216, 2016).
Family Phocoenidae (porpoises):
    Harbor Porpoise.................  Phocoena phocoena......  Gulf of Maine/Bay of     -, -, N             95,543 (0.31, 74,034,         851        164
                                                                Fundy.                                       2016).
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                                                               Order Carnivora--Pinnipedia
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Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  Western North Atlantic.  -, -, N             61,336 (0.08, 57,637,       1,729        339
                                                                                                             2018).
    Gray Seal.......................  Halichoerus grypus.....  Western North Atlantic.  -, -, N             27,300 (0.22, 22,785,       1,389      4,453
                                                                                                             2016).
    Harp Seal.......................  Pagophilus               Western North Atlantic.  -, -, N             7.6 M (UNK, 7.1, 2019)    426,000    178,573
                                       groenlandicus.
    Hooded Seal.....................  Cystophora cristata....  Western North Atlantic.  -, -, N             593,500 (UNK, UNK,            UNK      1,680
                                                                                                             2005).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)).
\2\ Endangered Species Act (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 stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments/ assessments/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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.

    As indicated above, all seven species (with seven managed stocks) 
in Table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. While several species 
of whales have been documented seasonally in New England waters, the 
spatial occurrence of these species is such that take is not expected 
to occur, and they are not discussed further beyond the explanation 
provided here. The humpback (Megaptera novaeangliae), fin (Balaenoptera 
physalus), sei (Balaenoptera borealis), sperm (Physeter macrocephalus) 
and North Atlantic right whales (Eubaleana glacialis) occur seasonally 
in the Atlantic Ocean, offshore of Rhode Island. However, due to the 
depths of Narragansett Bay and near shore location of the project area, 
these marine mammals are unlikely to occur in the project area. 
Therefore,

[[Page 78074]]

OMAO did not request, and NMFS is not authorizing takes of these 
species.
    A detailed description of the species to be affected by OMAO's 
construction activities, including brief introductions to the species 
and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, were provided in the Federal Register notice for the 
proposed IHA (87 FR 66133, November 2, 2022); since that time, we are 
not aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
that Federal Register notice for these descriptions. Please also refer 
to the NMFS' website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

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.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
                                                    Generalized hearing
                  Hearing group                           range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen whales)....  7 Hz to 35 kHz.
Mid-frequency (MF) cetaceans (dolphins, toothed   150 Hz to 160 kHz.
 whales, beaked whales, bottlenose whales).
High-frequency (HF) cetaceans (true porpoises,    275 Hz to 160 kHz.
 Kogia, river dolphins, Cephalorhynchid,
 Lagenorhynchus cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals).  50 Hz to 86 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions    60 Hz to 39 kHz.
 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).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from OMAO's activities have the 
potential to result in Level A and Level B harassment of marine mammals 
in the action area. The notice of the proposed IHA (87 FR 66133, 
November 2, 2022) included a discussion of the effects of anthropogenic 
noise on marine mammals and the potential effects of underwater noise 
from OMAO's construction activities on marine mammals and their 
habitat. That information and analysis is referenced in this final IHA 
determination and is not repeated here; please refer to the notice of 
the proposed IHA (87 FR 66133, November 2, 2022).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through this IHA, which will inform both NMFS' consideration 
of ``small numbers'' and the negligible impact determinations.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes will primarily be by Level B harassment, as use of 
the acoustic sources (i.e., pile driving and removal, DTH, and rotary 
drilling) 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 high 
frequency species and phocids because predicted auditory injury zones 
are larger than for mid-frequency species. Auditory injury is unlikely 
to occur for mid-frequency species. The 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 
authorized for this activity. Below we describe how the authorized take 
numbers are estimated.
    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

[[Page 78075]]

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 authorized 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). Thresholds have also been developed identifying the 
received level of in-air sound above which exposed pinnipeds would 
likely be behaviorally harassed.
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources. Generally speaking, Level B harassment take 
estimates based on these behavioral harassment thresholds are expected 
to include any likely takes by TTS as, in most cases, the likelihood of 
TTS occurs at distances from the source less than those at which 
behavioral harassment is likely. TTS of a sufficient degree can 
manifest as behavioral harassment, as reduced hearing sensitivity and 
the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    OMAO's activities includes the use of continuous (vibratory hammer/
rotary drill/DTH mono-hammer) and impulsive (impact hammer/DTH mono-
hammer) 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) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). OMAO's 
activity includes the use of impulsive (impact hammer/DTH mono-hammer) 
and non-impulsive (vibratory hammer/rotary drill/DTH mono-hammer) 
sources.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                        PTS onset thresholds \*\ (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lp,0-pk,flat: 219   Cell 2: LE,p, LF,24h: 199 dB.
                                          dB; LE,p, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p, MF,24h: 198 dB.
                                          dB; LE,p, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lp,0-pk,flat: 202   Cell 6: LE,p, HF,24h: 173 dB.
                                          dB; LE,p, HF,24h: 155 dB.
Phocid Pinnipeds (PW)(Underwater)......  Cell 7: Lp,0-pk.flat: 218   Cell 8: LE,p, PW,24h: 201 dB.
                                          dB; LE,p, PW,24h: 185 dB.
Otariid Pinnipeds (OW)(Underwater).....  Cell 9: Lp,0-pk,flat: 232   Cell 10: LE,p, OW,24h: 219 dB.
                                          dB; LE,p, OW,24h: 203 dB..
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 sound pressure level thresholds
  associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,p) has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
  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 thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the project. Marine 
mammals are expected to be affected via sound generated by the primary 
components of the project (i.e., impact pile driving, vibratory pile 
driving, vibratory pile removal, rotary drilling, and DTH).
    The intensity of underwater sound is greatly influenced by factors, 
such as the size and type of piles, type of driver or drill, and the 
physical environment in which the activity takes place. In order to 
calculate distances to the Level A harassment and Level B harassment 
thresholds for the methods and piles being used in this project, NMFS 
used representative source levels (Table 4)

[[Page 78076]]

from acoustic monitoring at other locations.

                                                   Table 4--Source Levels for Construction Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     SEL (dB re 1
              Method                      Pile type             Pile diameter        Peak (dB re 1   RMS (dB re 1    [mu]Pa 2-sec         Reference
                                                                                        [mu]Pa)         [mu]Pa)          sec)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Extraction..............  Steel pipe \1\.......  12''...................             171             155             155  Caltrans 2020, Table
                                                                                                                                     1.2-1d.
                                    Timber...............  12''...................              NA             152              NA  NMFS 2021a, Table 4.
Vibratory Installation............  Steel pipe...........  18''...................              NA         \2\ 162             162  NAVFAC Mid-Atlantic
                                                                                                                                     2019, Table 6-4.
                                    Sheet pile...........  Z26-700 \3\............              NA             156              NA  Navy 2015.
                                    Steel pipe...........  30''...................              NA             167             167  Navy 2015, p.14.
                                    Casing/shaft for       36''...................              NA             175             175  NAVFAC Mid-Atlantic
                                     steel pipe.                                                                                     2019, Table 6-4.
DTH Mono-hammer...................  Steel pipe...........  18''...................             172             167             146  Egger, 2021; Guan
                                                                                                                                     and Miner 2020;
                                                                                                                                     Heyvaert and Reyff,
                                                                                                                                     2021.
                                    Casing/shaft for       36'' \4\...............             194             167             164  Reyff and Heyvaert
                                     steel pipe.                                                                                     2019; Reyff 2020;
                                                                                                                                     and Denes et al.
                                                                                                                                     2019.
Rotary Drilling...................  Steel pipe...........  18'' and 30''..........              NA             154              NA  Dazey et al. 2012.
Impact Install....................  Steel pipe \5\.......  18''...................             208             187             176  Caltrans 2020, Table
                                                                                                                                     1.2-1a.
                                    Steel pipe...........  30''...................             211             196             181  NAVFAC Southwest
                                                                                                                                     2020, p.A-4.
Vibratory Installation/Extraction.  Steel pipe...........  16''...................              NA             162             162  NAVFAC Mid-Atlantic
                                                                                                                                     2019, Table 6-4.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 13-inch steel pipe used as proxy because data were not available for vibratory install/extract of 12-inch steel pipe.
\2\ Although conservative, this 162 dB RMS is consistent with source level value used for 18-inch steel pipe in for Dry Dock 1 at Portsmouth Naval
  Shipyard (84 FR 13252, April 4, 2019).
\3\ 30-inch steel pipe pile used as the proxy source for vibratory driving of steel sheet piles because data were not available for Z26-700 (Navy 2015
  [p. 14]).
\4\ Guidance from NMFS states: For each metric, select the highest SL provided among these listed references (Reyff and Heyvaert, 2019); (Reyff J.,
  2020); (Denes et al., 2019).
\5\ Impact install of 20-inch steel pipe used as proxy because data were not available for 18-inch.
Notes: All SPLs are unattenuated; dB = decibels; NA = Not applicable/Not available; RMS = root mean square; SEL = sound exposure level; Caltrans =
  California Department of Transportation; NAVFAC = Naval Facilities Engineering Systems Command; dB re 1 [mu]Pa = dB referenced to a pressure of 1
  microPascal, measures underwater SPL. dB re 1 [mu]Pa2-sec = dB referenced to a pressure of 1 microPascal squared per second, measures underwater SEL.
  Single strike SEL are the proxy source levels presented for impact pile driving and were used to calculate distances to PTS. All data referenced at 10
  meters.

    NMFS recommends treating DTH systems as both impulsive and 
continuous, non-impulsive sound source types simultaneously. Thus, 
impulsive thresholds are used to evaluate Level A harassment, and 
continuous thresholds are used to evaluate Level B harassment. With 
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A 
harassment based on available data regarding DTH systems of similar 
sized piles and holes (Denes et al., 2019; Guan and Miner, 2020; Reyff 
and Heyvaert, 2019; Reyff, 2020; Heyvaert and Reyff, 2021) (Table 1 in 
the Federal Register notice for the proposed IHA (87 FR 66133, November 
2, 2022) includes number of piles and duration; Table 4 includes sound 
pressure levels for each pile type). At the time of the Navy's 
application submission, NMFS recommended a proxy RMS sound pressure 
level at 10 m of 167 dB when evaluating Level B harassment (Heyvaert 
and Reyff, 2021) for all DTH pile/hole sizes. However, since that time, 
NMFS has received additional clarifying information regarding DTH data 
presented in Reyff and Heyvaert (2019) and Reyff (2020) that allows 
NMFS to recommend different RMS sound pressure levels at 10 m for 
piles/holes of varying diameters. Therefore, NMFS proposes to use the 
following proxy RMS sound pressure levels at 10 m to evaluate Level B 
harassment from this sound source in this analysis (Table 5): 167 dB 
RMS for the 18 inch steel pipe piles (Heyvaert and Reyff, 2021) and 174 
dB RMS for the 36 inch steel shafts (Reyff and Heyvaert, 2019; Reyff, 
2020).

Level B Harassment Zones

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * 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.

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, known as practical spreading. As 
is common practice in coastal waters, here we assume practical 
spreading (4.5 dB reduction in sound level for each doubling of 
distance). Practical spreading was used to determine sound propagation 
for this project.
    The TL model described above was used to calculate the expected 
noise propagation from vibratory pile driving/extracting, impact pile 
driving, rotary drilling, and DTH mono-hammer excavation using 
representative source levels to estimate the harassment zones or area 
exceeding the noise criteria. Utilizing the described practical 
spreading model, NMFS calculated the Level B isopleths shown in Tables 
5 and 6. The largest calculated Level B isopleth, with the exception of 
concurrent activities, discussed below, is 46,416 m for the vibratory 
installation of the 36'' steel casing/shaft guide piles with rock 
socket to build the small boat floating dock; however, this distance is 
truncated by shoreline in all directions, so sound will not reach the 
full distance of the calculated Level B harassment isopleth. This 
activity will generate a maximum ensonified area of 3.31 km\2\ (Table 
6). The maximum ensonified area of 8.53 km\2\ is generated by the 
vibratory installation of the 16'' steel pipe pile, 18'' steel pipe 
pile, and 30'' steel pipe

[[Page 78077]]

pile as well as the vibratory installation/extraction of the 16'' steel 
pipe template piles. This area represents the maximum area after which 
distances are truncated.

Level A Harassment Zones

    The ensonified area associated with Level A harassment is 
technically more 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, this optional 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 are 
reported in Table 1 of the Federal Register notice announcing the 
proposed IHA (87 FR 66133, November 2, 2022) (number piles/day and 
duration to drive a single pile) and Table 4 (source levels/distance to 
source levels). The resulting estimated isopleths are reported below in 
Tables 5 and 6. The largest Level A isopleth will be generated by the 
impact driving of the 30'' steel pipe pile at the pier for high-
frequency cetaceans (3,500.3 m; Table 5). This activity will have a 
maximum ensonified area of 6.49 km\2\ (Table 5).

                         Table 5--Maximum Distances to Level A Harassment and Level B Harassment Thresholds for Impulsive Sound
                                                           [Impact hammer and DTH mono-hammer]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Level A (PTS onset) harassment                  Level B
                                                                                 ------------------------------------------------------    harassment
                                                                                       Maximum           Maximum           Maximum     -----------------
                                                                                  distance to  185  distance to  155  distance to  185       Maximum
                                                                                      dB SELcum         dB SELcum         dB SELcum     distance  160 dB
                                                                                    threshold(m)/     threshold(m)/     threshold(m)/   RMS SPL  (120 dB
             Structure                Pile size and type          Activity             area of           area of           area of       DTH)  threshold
                                                                                   harassment zone   harassment zone   harassment zone    (m)/ area of
                                                                                       (km\2\)           (km\2\)           (km\2\)       harassment zone
                                                                                 ------------------------------------------------------      (km\2\)
                                                                                                                                       -----------------
                                                                                     MF cetacean       HF cetacean         Phocid          All marine
                                                                                                                                             mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bulkhead construction (Combination  18'' steel pipe......  Impact Install.......       48.5/0.0037      1,624.7/0.66        729.9/0.21          631/0.16
 Pipe/Z-pile).                                             DTH Mono-Hammer......      4.6/0.000033       154.2/0.028       69.3/0.0075       13,594/3.31
Trestle (Bents 1-18)..............  18'' steel pipe......  Impact Install.......       25.2/0.0020        844.9/1.21        379.6/0.38          631/0.82
Trestle (Bent 19).................  30'' steel pipe......  Impact Install.......        65.8/0.014      2,205.0/3.72        990.7/1.47        2,512/4.44
Pier..............................  30'' steel pipe......  Impact Install.......       104.5/0.034      3,500.3/6.49      1,572.6/2.50        2,512/4.44
Gangway support piles (small boat   18'' steel pipe......  Impact Install.......      19.3/0.00058        644.8/0.17       289.7/0.049          631/0.16
 floating dock).
Small Boat Floating Dock..........  36'' Steel Casing/     Impact Install.......        35.5/0.002      1,189.5/0.45        534.4/0.12        3,415/2.14
                                     Shaft with Rock       DTH Mono-Hammer......         73/0.0084      2,444.5/1.21      1,098.2/0.42       13,594/3.31
                                     Socket (Guide Pile).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: dB = decibel; DTH = down-the-hole; dB RMS SPL = decibel root mean square sound pressure level; dB SELcum = cumulative sound exposure level; m =
  meter; PTS = Permanent Threshold Shift; km\2\ = square kilometer.


                            Table 6--Maximum Distances to Level A Harassment and Level B Harassment Thresholds for Continuous
                                                             [Vibratory hammer/rotary drill]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Level A (PTS onset) harassment                  Level B
                                                                                 ------------------------------------------------------    harassment
                                                                                       Maximum           Maximum           Maximum     -----------------
                                                                                  distance to  198  distance to  173  distance to  201       Maximum
                                                                                      dB SELcum         dB SELcum         dB SELcum     distance  120 dB
                                                                                    threshold(m)/     threshold(m)/     threshold(m)/        RMS SPL
             Structure                Pile size and type          Activity             area of           area of           area of        threshold(m)/
                                                                                   harassment zone   harassment zone   harassment zone       area of
                                                                                       (km\2\)           (km\2\)           (km\2\)       harassment zone
                                                                                 ------------------------------------------------------      (km\2\)
                                                                                                                                       -----------------
                                                                                     MF cetacean       HF cetacean         Phocid          All marine
                                                                                                                                             mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abandoned guide piles along         12'' steel pipe......  Vibratory Extract....             0.3/0      5.3/0.000044      2.2/0.000008        2,514/1.26
 bulkhead.
Floating dock demolition (Timber    12'' timber..........  Vibratory Extract....             0.2/0        4/0.000025      1.7/0.000005        1,359/0.53
 Guide Piles).
Bulkhead construction (Combination  18'' steel pipe......  Vibratory Install....      1.8/0.000005       29.7/0.0014      12.2/0.00023        6,310/3.31
 Pipe/Z-pile).                      Steel sheet Z26-700..  Vibratory Install....      0.7/0.000001      11.8/0.00022      4.9/0.000038        2,512/1.26
                                    16'' steel pipe        Vibratory Install/         1.1/0.000002      18.7/0.00055      7.7/0.000093        6,310/3.31
                                     template piles.        Extract.
Trestle (Bents 1-18)..............  18'' steel pipe......  Vibratory Install....      0.7/0.000002      11.8/0.00044      4.8/0.000072        6,310/8.53
                                    18'' steel pipe hole.  Rotary Drill.........             0.0/0      0.6/0.000001      0.4/0.000001        1,848/2.98
                                    16'' steel pipe        Vibratory Install/         1.1/0.000004       18.7/0.0011       7.7/0.00019        6,310/8.53
                                     template piles.        Extract.
Trestle (Bent 19).................  30'' steel pipe......  Vibratory Install....      2.0/0.000013       33.2/0.0034      13.7/0.00059       13,594/8.53

[[Page 78078]]

 
                                    16'' steel pipe        Vibratory Install/         1.1/0.000004       18.7/0.0011       7.7/0.00019        6,310/8.53
                                     template piles.        Extract.
Pier..............................  30'' steel pipe......  Vibratory Install....      3.2/0.000032       52.8/0.0087       21.7/0.0015       13,594/8.53
                                    30'' hole............  Rotary Drill.........             0.0/0      0.6/0.000001      0.4/0.000001        1,848/2.98
                                    16'' steel pipe        Vibratory Install/         1.1/0.000004       18.7/0.0011       7.7/0.00019        6,310/8.53
                                     template piles.        Extract.
Fender Piles......................  16'' steel pipe......  Vibratory Install....      0.9/0.000003      14.3/0.00064       5.9/0.00011        6,310/8.53
                                    16'' steel pipe        Vibratory Install/         1.1/0.000004       18.7/0.0011       7.7/0.00019        6,310/8.53
                                     template piles.        Extract.
Gangway support piles (small boat   18'' steel pipe......  Vibratory Install....      0.7/0.000001      11.8/0.00022      4.8/0.000036        6,310/3.31
 floating dock).
Small Boat Floating Dock..........  36'' Steel Casing/     Vibratory Install....      5.2/0.000042        86.6/0.012        35.6/0.002       46,416/3.31
                                     Shaft Guide Piles
                                     with Rock Socket.
                                    16'' steel pipe        Vibratory Install/         1.1/0.000002      18.7/0.00055      7.7/0.000093        6,310/3.31
                                     template piles.        Extract.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: dB = decibel; dB RMS SPL = decibel root mean square sound pressure level; dB SELcum = cumulative sound exposure level; m = meter; PTS = Permanent
  Threshold Shift; km\2\ = square kilometer.

Concurrent Activities

    Simultaneous use of two or three impact, vibratory, or DTH hammers, 
or rotary drills, could occur (potential combinations described in 
Table 1 of the Federal Register notice announcing the proposed IHA; 87 
FR 66133, November 2, 2022) and may result in increased sound source 
levels and harassment zone sizes, given the proximity of the structure 
sites and the rules of decibel addition (Table 7).
    NMFS (2018b) handles overlapping sound fields created by the use of 
more than one hammer differently for impulsive (impact hammer and Level 
A harassment zones for drilling with a DTH hammer) and continuous sound 
sources (vibratory hammer, rotary drill, and Level B harassment zones 
for drilling with a DTH hammer (Table 7) and differently for impulsive 
sources with rapid impulse rates of multiple strikes per second (DTH) 
and slow impulse rates (impact hammering) (NMFS, 2021c). It is unlikely 
that the two impact hammers will strike at the same instant, and 
therefore, the SPLs will not be adjusted regardless of the distance 
between impact hammers. In this case, each impact hammer will be 
considered to have its own independent Level A harassment and Level B 
harassment zones.
    When two DTH hammers operate simultaneously their continuous sound 
components overlap completely in time. When the Level B isopleth of one 
DTH sound source encompasses the isopleth of another DTH sound source, 
the sources are considered additive and combined using the rules for 
combining sound source levels generated during pile installation, 
described in Table 7.

               Table 7--Rules for Combining Sound Source Levels Generated During Pile Installation
----------------------------------------------------------------------------------------------------------------
            Hammer types                  Difference in SSL            Level A zones           Level B zones
----------------------------------------------------------------------------------------------------------------
Vibratory, Impact..................  Any........................  Use impact zones......  Use largest zone.
Impact, Impact.....................  Any........................  Use zones for each      Use zone for each pile
                                                                   pile size and number    size.
                                                                   of strikes.
Vibratory, Vibratory Rotary drill,   0 or 1 dB..................  Add 3 dB to the higher  Add 3 dB to the higher
 or DTH, DTH.                        2 or 3 dB..................   source level.           source level.
                                                                  Add 2 dB to the higher  Add 2 dB to the higher
                                                                   source level.           source level.
                                     4 to 9 dB..................  Add 1 dB to the higher  Add 1 dB to the higher
                                                                   source level.           source level.
                                     10 dB or more..............  Add 0 dB to the higher  Add 0 dB to the higher
                                                                   source level.           source level.
----------------------------------------------------------------------------------------------------------------
Note: The method is based on a method created by Washington State Department of Transportation (WSDOT 2020) and
  has been updated and modified by NMFS.

    When two continuous noise sources have overlapping sound fields, 
there is potential for higher sound levels than for non-overlapping 
sources. When two or more continuous noise sources are used 
simultaneously, and the isopleth of one sound source encompasses the 
isopleth of another sound source, the sources are considered additive 
and source levels are combined using the rules of decibel addition 
(Table 8; NMFS, 2021c).
    For simultaneous use of three or more continuous sound sources, 
NMFS first identifies the three overlapping sources with the highest 
sound source level. Then, using the rules for combining sound source 
levels generated during

[[Page 78079]]

pile installation (Table 8), NMFS determines the difference between the 
lower two source levels, and adds the appropriate number of decibels to 
the higher source level of the two. Then, NMFS calculates the 
difference between the newly calculated source level and the highest 
source level of the three identified in the first step, and again, adds 
the appropriate number of decibels to the highest source level of the 
three.
    For example, with overlapping isopleths from 24'', 36'', and 42'' 
diameter steel pipe piles with sound source levels of 161, 167, and 168 
dB RMS respectively, NMFS would first calculate the difference between 
the 24'' and 36'' source levels (167 dB - 161 dB = 6 dB). Then, given 
that the difference is 6 dB, as described in Table 8, NMFS would then 
add 1 dB to the highest of the two sound source levels (167 dB), for a 
combined noise level of 168 dB. Next, NMFS calculates the difference 
between the newly calculated 168 dB and the sound source level of the 
42'' steel pile (168 dB). Since 168 dB - 168 dB = 0 dB, 3 dB is added 
to the highest value (168 dB + 3 dB = 171 dB). Therefore, for the 
combination of 24'', 36'', and 42'' steel pipe piles, zones would be 
calculated using a combined sound source level of 171 dB.
    If an impact hammer and a vibratory hammer are used concurrently, 
the largest Level B harassment zone generated by either hammer would 
apply, and the Level A harassment zone generated by the impact hammer 
would apply. Simultaneous use of two or more impact hammers does not 
require source level additions as it is unlikely that two hammers would 
strike at the same exact instant. Thus, sound source levels are not 
adjusted regardless of distance, and the zones for each individual 
activity apply.
    For activity combinations that do require sound source level 
adjustment, Table 9 shows the revised proxy source levels for 
concurrent activities based upon the rules for combining sound source 
levels generated during pile installation, described in Table 7. 
Resulting Level A harassment and Level B harassment zones for 
concurrent activities are summarized in Table 9. The maximum Level A 
harassment isopleth will be 2,444.5 m for high-frequency cetaceans 
generated by concurrent use of two vibratory pile drivers and DTH mono-
hammer during installation of 36'' shafts for the small boat floating 
dock (Table 9). The maximum Level B harassment isopleth will be 54,117 
m for the concurrent use of DTH mono-hammer and two vibratory pile 
drivers for installation of 36'' shafts for the small boat floating 
dock (Table 9).

   Table 8--Proxy Values for Simultaneous Use of Non-Impulsive Sources
------------------------------------------------------------------------
          Structure              Activity and proxy        New proxy
------------------------------------------------------------------------
Bulkhead.....................  Vibratory Install 16-  165 dB RMS.
                                inch steel pipe
                                piles--162 dB RMS.
                               Vibratory Install 18-
                                inch steel pipe
                                piles--162 dB RMS.
                               Vibratory Install 18-  168 dB RMS.
                                inch steel pipe
                                piles--162 dB.
                               DTH Install 18-inch
                                steel pipe piles--
                                167 dB.
------------------------------------------------------------------------
Bulkhead and Trestle.........  Vibratory Install/     166 dB RMS.
                                extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Vibratory Install Z26-
                                700 sheet piles--156
                                dB RMS.
                               Vibratory Install 18-
                                inch steel pipe
                                piles--162 dB RMS.
                               Vibratory Install/     163 dB RMS.
                                extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Vibratory Install Z26-
                                700 sheet piles--156
                                dB RMS.
                               Rotary Drill 18-inch
                                steel pipe piles--
                                154 dB RMS.
------------------------------------------------------------------------
Pier.........................  Vibratory Install/     168 dB RMS.
                                extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Vibratory Install 30-
                                inch steel pipe
                                piles--167 dB RMS.
                               Vibratory Install/     163 dB RMS.
                                extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Rotary Drill 30-inch
                                steel pipe piles--
                                154 dB RMS.
------------------------------------------------------------------------
Pier Fender Piles and Small    Vibratory Install/     165 dB RMS.
 Boat Floating Dock.            extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Vibratory Install 18-
                                inch steel pipe
                                piles--162 dB RMS.
                               Vibratory Install/     175 dB RMs.
                                extract 16-inch
                                steel pipe piles--
                                162 dB RMS.
                               Vibratory Install 36-
                                inch steel pipe
                                piles--175 dB RMS.
                               Vibratory Install 36-  176 dB.
                                inch steel casing--
                                175 dB.
                               DTH Install 36-inch
                                steel casing--167 dB.
------------------------------------------------------------------------


                            Table 9--Maximum Distances to Level A and Level B Harassment Thresholds for Concurrent Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Level A (PTS onset) harassment                  Level B
                                                                                 --------------------------------------------------------   harassment
                                                                                   Maximum distance   Maximum distance  Maximum distance ---------------
                                                                                  to continuous 198  to continuous 173    to continuous
                                                                                    dB SELcum; DTH     dB SELcum; DTH    201 dB SELcum;       Maximum
                                                                                    185 dB SELcum      155 dB SELcum       DTH 185 dB      distance 120
                                  Pile sizes and                         Total     thresholds (m)/    thresholds (m)/        SELcum         dB RMS SPL
           Structure                   type             Activity      production       area of            area of        thresholds (m)/  threshold (m)/
                                                                         days      harassment zone    harassment zone        area of          area of
                                                                                       (km\2\)            (km\2\)        harassment zone    harassment
                                                                                                                             (km\2\)       zone (km\2\)
                                                                                 --------------------------------------                     (continuous
                                                                                                                       ------------------    and DTH)
                                                                                     MF cetacean        HF cetacean          Phocid
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bulkhead......................  Install of 16-     Install/Extract            15  3.7/0.000021.....  61.6/0.0060......  25.3/0.001......     10,000/3.31
                                 inch and 18-inch   using two
                                 steel pipe piles.  Vibratory Pile
                                                    Drivers.

[[Page 78080]]

 
                                Install of 18-     Install using two          12  Vibratory: 1.8/    Vibratory: 29.7/   Vibratory: 12.2/  15,848.93/3.31
                                 inch steel pile.   Vibratory Pile                 0.000005 DTH:      0.0014 DTH:        0.00023 DTH:
                                                    Drivers and DTH                4.6/0.000033.      154.2/0.028.       69.3/0.0075.
                                                    mono-hammer.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bulkhead and Trestle..........  Install of 16-     Install/Extract            15  4.1/0.000026.....  68.3/0.0073......  28.1/0.0012.....     10,000/3.31
                                 inch and 18-inch   using three               14  2.9/0.000013.....  47.8/0.0036......  19.7/0.00061....      7,356/3.31
                                 steel pipe and     Vibratory Pile
                                 Z26-700 steel      Drivers.
                                 sheet piles.      Install/Extract
                                                    using two
                                                    Vibratory Pile
                                                    Drivers and a
                                                    Rotary Drill.
Pier..........................  Install of 16-     Install/Extract            30  5.9/0.00011......  97.6/0.030.......  40.1/0.0050.....     15,849/8.53
                                 and 30-inch        using two
                                 steel pipe.        Vibratory Pile
                                                    Drivers.
                                                   Install/Extract            27  2.0/0.0031.......  33.1/0.0034......  13.6/0.00058....      7,356/8.53
                                                    using a
                                                    vibratory pile
                                                    driver and
                                                    rotary drill.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pier Fender Piles and Gangway   Install of 16-     Install/Extract            17  2.3/0.000017.....  38.8/0.0047......  16.0/0.0008.....     10,000/8.53
 Support for Small Boat          and 18-inch        using two                 20  9.6/0.00029......  159.5/0.080......  65.6/0.013......     46,416/8.53
 Floating Dock.                  steel pipe.        Vibratory Pile
                                                    Drivers.
                                                   Install using two
                                                    Vibratory Pile
                                                    Drivers.
                                Install of 16-
                                 inch steel pipe
                                 and 36-inch
                                 shafts.
                                Install of 36-     Install using two           2  Vibratory: 5.2/    Vibratory: 86.6/   Vibratory: 35.6/    DTH: 54,117/
                                 inch shafts.       Vibratory Pile                 0.000042 DTH: 73/  0.012 DTH:         0.002 DTH:                 8.53
                                                    Drivers and DTH                0.0084.            2,444.5/1.21.      1,098.2/0.42.
                                                    mono-hammer.
--------------------------------------------------------------------------------------------------------------------------------------------------------
dB RMS SPL = decibel root mean square sound pressure level; dB SELcum = cumulative sound exposure level; m = meter; PTS = Permanent Threshold Shift;
  km\2\ = square kilometer.

    The Level B harassment zones in Table 9 were calculated based upon 
the adjusted source levels for simultaneous construction activities 
(Table 8). OMAO has not planned any scenarios for concurrent work in 
which the Level A harassment isopleths would need to be adjusted from 
that calculated for single sources. Regarding implications for Level A 
harassment zones when multiple vibratory hammers, or vibratory hammers 
and rotary drills, are operating concurrently, given the small size of 
the estimated Level A harassment isopleths for all hearing groups 
during vibratory pile driving, the zones of any two hammers or hammer 
and drill are not expected to overlap. Therefore, compounding effects 
of multiple vibratory hammers operating concurrently are not 
anticipated, and NMFS has treated each source independently.
    Regarding implications for Level A harassment zones when vibratory 
hammers are operating concurrently with a DTH hammer, combining 
isopleths for these sources is difficult for a variety of reasons. 
First, vibratory pile driving relies upon non-impulsive PTS thresholds, 
while DTH hammers use impulsive thresholds. Second, vibratory pile 
driving accounts for the duration to drive a pile, while DTH account 
for strikes per pile. Thus, it is difficult to measure sound on the 
same scale and combine isopleths from these impulsive and non-
impulsive, continuous sources. Therefore, NMFS has treated each source 
independently at this time.
    Regarding implications for impact hammers used in combination with 
a vibratory hammer or DTH hammer, the likelihood of these multiple 
sources' isopleths completely overlapping in time is slim primarily 
because impact pile driving is intermittent. Furthermore, non-
impulsive, continuous sources rely upon non-impulsive TTS/PTS 
thresholds, while impact pile driving uses impulsive thresholds, making 
it difficult to calculate isopleths that may overlap from impact 
driving and the simultaneous action of a non-impulsive continuous 
source or one with multiple strikes per second. Thus, with such slim 
potential for multiple different sources' isopleths to overlap in space 
and time, specifications should be entered as ``normal'' into the User 
Spreadsheet for each individual source separately.

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
will inform the take calculations. Potential exposures to construction 
noise for each acoustic threshold were estimated using marine mammal 
density estimates (N) from the Navy Marine Species Density Database 
(NMSDD) (Navy, 2017a).

[[Page 78081]]

OMAO evaluated data reflecting monthly densities of each species to 
determine minimum, maximum, and average annual densities within 
Narragansett Bay. Table 10 summarizes the average annual densities of 
species that may be impacted by the construction activities, with the 
exception of harbor seals as the density value for this species in the 
table represents the maximum density value for seals.

    Table 10--Average Densities by Species Used in Exposure Analysis
------------------------------------------------------------------------
                                                        Average density
                                                        in project area
                       Species                            (species per
                                                             km\2\)
------------------------------------------------------------------------
Atlantic White-sided Dolphin.........................              0.003
Common Dolphin.......................................              0.011
Harbor Porpoise......................................              0.012
Harbor Seal..........................................              0.623
Gray Seal............................................              0.131
Harp Seal............................................               0.05
Hooded Seal..........................................              0.001
------------------------------------------------------------------------

    The NMSDD models reflect densities for seals as a guild due to 
difficulty in distinguishing these species at sea. Harbor seal is 
expected to be the most common pinniped in Narragansett Bay with year-
round occurrence (Kenney and Vigness-Raposa, 2010). Therefore, OMAO 
used the maximum density for the seal guild for harbor seal. Gray seals 
are the second most common seal to be observed in Rhode Island waters 
and, based on stranding records, are commonly observed during the 
spring to early summer and occasionally observed during other months of 
the year (Kenney, 2020). Therefore, the average density for the seal 
guild was used for gray seal occurrence in Narragansett Bay. Minimum 
densities for the seal guild were used for harp seal and hooded seals 
as they are considered occasional visitors in Narragansett Bay but are 
rare in comparison to harbor and gray seals (Kenney, 2015). NMFS has 
carefully reviewed and concurs with the use of these densities used by 
OMAO.

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and authorized.
    For each species, OMAO multiplied the average annual density by the 
largest ensonified area (Tables 5, 6, 9) and the maximum days of 
activity (Tables 5, 6, 9) (take estimate = N x ensonified area x days 
of pile driving) in order to calculate estimated take by Level A 
harassment and Level B harassment. OMAO used the pile type, size, and 
construction method that produce the largest isopleth to estimate 
exposure of marine mammals to noise impacts. The exposure estimate was 
rounded to the nearest whole number at the end of the calculation. 
Table 11 shows the total estimated number of takes for each species by 
Level A harassment and Level B harassment for individual and concurrent 
activities as well as estimated take as a percent of stock abundance. 
Estimated take by activity type for individual and concurrent equipment 
use for each species is shown in Tables 6-12 through 6-17 in the 
application. OMAO requested take by Level A harassment of four species 
(harbor porpoise, harbor seal, gray seal, and harp seal) incidental to 
construction activities using one equipment type. In addition, OMAO 
requested one take of harbor seals by Level A harassment during 
concurrent use of a DTH mono-hammer and two vibratory hammers for 
installation of 36'' shafts for the small boat floating dock.
    To account for group size, OMAO conservatively increased the 
estimated take by Level B harassment from 9 to 16 Atlantic white-sided 
dolphins, as the calculated take was less than the documented average 
group size (NUWC, 2017). NMFS agrees with this approach, and is 
authorizing 16 takes by Level B harassment of Atlantic white-sided 
dolphins. The species density for the hooded seal was too low to result 
in any calculated estimated takes. In order to be conservative, OMAO 
requested, and NMFS authorized, one take by Level B harassment of 
hooded seals for each month of construction activity when this species 
may occur in the project area. Hooded seals may occur in the project 
area from January through May, which is a total of 5 months. Therefore, 
OMAO requested, and NMFS authorized, five takes by Level B harassment 
of hooded seals for individual construction activities and five takes 
by Level B harassment of hooded seals for concurrent construction 
activities for a total of 10 takes by Level B harassment of hooded 
seals.

                  Table 11--Total Authorized Take by Level A Harassment and Level B Harassment for Individual and Concurrent Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Individual activities           Concurrent activities
                                                         ----------------------------------------------------------------      Total
                         Species                              Level A         Level B         Level A         Level B       authorized      % of stock
                                                            harassment      harassment      harassment      harassment         take
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic white-sided dolphin............................               0               6               0               3          \1\ 16             0.2
Short-beaked common dolphin.............................               0              26               0              13              39             0.2
Harbor Porpoise.........................................               2              27               0              13              42           0.044
Harbor Seal.............................................              55           1,478               1             589           2,123            3.46
Gray Seal...............................................              11             312               0             125             448            1.64
Harp Seal...............................................               4             117               0              47             168           0.002
Hooded Seal.............................................               0           \2\ 5               0           \2\ 5              10           0.002
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Authorized take has been increased to mean group size (NUWC, 2017). Mean group size was not used for those take estimates that exceeded the mean
  group size.
\2\ OMAO conservatively requested 1 take by Level B harassment of hooded seal per month of construction when this species may occur in the project area
  (January through May).

Mitigation

    In order to issue an IHA 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

[[Page 78082]]

conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks, and 
their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost and impact on 
operations.

Shutdown Zones

    OMAO will establish shutdown zones for all pile driving activities. 
The purpose of a shutdown zone is generally to define an area within 
which shutdown of the activity would occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area). 
Shutdown zones will be based upon the Level A harassment zone for each 
pile size/type and driving method, as shown in Table 12. If the Level A 
harassment zone is too large to monitor, the shutdown zone will be 
limited to a radial distance of 200 m from the acoustic source (86 FR 
71162, December 15, 2021; 87 FR 19886, April 6, 2022). For example, the 
largest Level A harassment zone for high-frequency cetaceans extends 
approximately 2,444.5 m from the source during DTH mono-hammer 
excavation while installing the 36 in steel shafts for the small boat 
floating dock (Table 5). OMAO plans to maintain maximum shutdown zone 
of 200 m for that activity, consistent with prior projects in the area 
(87 FR 11860, March 2, 2022).
    A minimum shutdown zone of 10 m will be applied for all in-water 
construction activities if the Level A harassment zone is less than 10 
m (i.e., vibratory pile driving, drilling). The 10 m shutdown zone will 
also serve to protect marine mammals from collisions with project 
vessels during pile driving and other construction activities, such as 
barge positioning or drilling. If an activity 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 indicated in Table 12 or 15 minutes 
have passed without re-detection of the animal. Construction activities 
must be halted upon observation of 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.
    If a marine mammal enters the Level B harassment zone, in-water 
work will proceed and PSOs will document the marine mammal's presence 
and behavior.

                        Table 12--Shutdown Zones and Level B Harassment Zones by Activity
----------------------------------------------------------------------------------------------------------------
                                                                  Shutdown zone (m)          Level B harassment
                                                          --------------------------------        zone (m)
          Pile type/size                Driving method                                    ----------------------
                                                              Cetaceans       Pinnipeds      All marine mammals
----------------------------------------------------------------------------------------------------------------
12'' steel pipe...................  Vibratory extraction.              10              10  2,600.
12'' timber.......................  Vibratory extraction.              15              10  1,359.
16'' steel pipe...................  Vibratory install/                 20              10  6,400.
                                     extract.
18'' steel pipe...................  Impact install.......         \1\ 200         \1\ 200  640.
                                    Vibratory install....              30              15  6,400.
                                    DTH Mono-hammer......         \1\ 200         \1\ 200  Maximum harassment
                                                                                            zone.\2\
                                    Rotary drilling 18''               10              10  1,900.
                                     holes.
Z26-700 steel sheets..............  Vibratory install....              15              10  2,600.
30'' steel pipe...................  Impact install.......         \1\ 200         \1\ 200  2,600.
                                    Vibratory install....              55              25  Maximum harassment
                                                                                            zone.\2\
30'' steel pipe...................  Rotary drilling......              10              10  1,900.
36'' steel pipe...................  Impact install.......         \1\ 200         \1\ 200  3,400.
                                    Vibratory install....              90              40  Maximum harassment
                                                                                            zone.\2\
36'' shafts.......................  DTH Mono-hammer......         \1\ 200         \1\ 200  Maximum harassment
                                                                                            zone.\2\
----------------------------------------------------------------------------------------------------------------
\1\ Distance to shutdown zone distances implemented for other similar projects in the region (NAVFAC, 2019).
\2\ Harassment zone will be truncated due to the presence of intersecting land masses and will encompass a
  maximum area of 3.31 km\2\.

Protected Species Observers

    The placement of protected species observers (PSOs) during all 
construction activities (described in the Monitoring and Reporting 
section) will ensure that the entire shutdown zone is visible. Should 
environmental conditions deteriorate such that the entire shutdown zone 
will not be visible (e.g., fog, heavy rain), pile driving will be 
delayed until the PSO is confident marine mammals within the shutdown 
zone could be detected.

Monitoring for Level A Harassment and Level B Harassment

    PSOs will monitor the full shutdown zones and the remaining Level A 
harassment and Level B harassment zones to the extent practicable. 
Monitoring zones provide utility for observing by establishing 
monitoring protocols for areas adjacent to the shutdown zones. 
Monitoring zones enable observers to be aware of and communicate the 
presence of marine mammals in the project areas outside the shutdown 
zones and thus prepare for a potential cessation of activity should the 
animal enter the shutdown zone.

Pre-Activity Monitoring

    Prior to the start of daily in-water construction activity, or 
whenever a break in pile driving of 30 minutes or longer occurs, PSOs 
will observe the

[[Page 78083]]

shutdown, Level A harassment, and Level B harassment for a period of 30 
minutes. Pile driving may commence following 30 minutes of observation 
when the determination is made that the shutdown zones are clear of 
marine mammals. If a marine mammal is observed within the shutdown 
zones listed in Table 13, construction activity will be delayed until 
the animal has voluntarily exited and been visually confirmed beyond 
the shutdown zone indicated in Table 13 or has not been observed for 15 
minutes. When a marine mammal for which Level B harassment take is 
authorized is present in the Level B harassment zone, activities will 
begin and Level B harassment take will be recorded. 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 are 
visible). If the shutdown zone is obscured by fog or poor lighting 
conditions, in-water construction activity will not be initiated until 
the entire shutdown zone is visible.

Soft-Start

    Soft-start procedures are used to provide additional protection to 
marine mammals by providing warning and/or giving marine mammals a 
chance to leave the area prior to the hammer operating at full 
capacity. For impact pile driving, contractors will be required 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. 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 OMAO's measures, NMFS has determined 
that the mitigation measures provide the means of effecting the least 
practicable impact on the affected species or stocks and their habitat, 
paying particular attention to rookeries, mating grounds, and areas of 
similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) 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 action; 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 in-water construction activities 
will be conducted by PSOs meeting NMFS' standards and in a manner 
consistent with the following:
     Independent PSOs (i.e., employees of the entity conducting 
construction activities may not serve as PSOs) who have no other 
assigned tasks during monitoring periods will be used;
     At least one PSO will 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 (degree in biological 
science or related field) or training for experience; and
     Where a team of three or more PSOs is required, a lead 
observer or monitoring coordinator will be designated. The lead 
observer will be required to have prior experience working as a marine 
mammal observer during construction.
    PSOs will 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, the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and 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.
    Visual monitoring will be conducted by a minimum of two trained 
PSOs positioned at suitable vantage points. Any activity for which the 
Level B harassment isopleth will exceed 1,900 meters will require a 
minimum of three PSOs to effectively monitor the entire Level B 
harassment zone. PSOs will likely be located on Gould Island South, 
Gould Island Pier, Coddington Point, Bishop Rock, Breakwater, or Taylor 
Point as shown in Figure 11-1 in the application. All PSOs will have 
access to high-quality binoculars, range finders to monitor distances, 
and a compass to record bearing to animals as well as radios or cells 
phones for maintaining contact with work crews.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after all in water construction activities. In addition, PSOs 
will record all incidents of marine mammal occurrence, regardless of 
distance from activity, and will document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
activities include the time to install or remove a single pile or 
series of piles, as long as the time elapsed between uses of the pile 
driving equipment is no more than 30 minutes.
    OMAO and the Navy shall conduct briefings between construction

[[Page 78084]]

supervisors and crews, PSOs, OMAO and Navy staff prior to the start of 
all pile driving activities and when new personnel join the work. These 
briefings will explain responsibilities, communication procedures, 
marine mammal monitoring protocol, and operational procedures.

Hydro-Acoustic Monitoring

    OMAO will implement in situ acoustic monitoring efforts to measure 
SPLs from in-water construction activities by collecting and evaluating 
acoustic sound recording levels during activities. Stationary 
hydrophones will be placed 33 ft (10 m) from the noise source, in 
accordance with NMFS' most recent guidance for the collection of source 
levels. If there is the potential for Level A harassment, a second 
monitoring location will be set up at an intermediate distance between 
cetacean/phocid shutdown zones and Level A harassment zones. 
Hydrophones will be deployed with a static line from a stationary 
vessel. Locations of hydro-acoustic recordings will be collected via 
GPS. A depth sounder and/or weighted tape measure will be used to 
determine the depth of the water. The hydrophone will be attached to a 
weighted nylon cord or chain to maintain a constant depth and distance 
from the pile area. The nylon cord or chain will be attached to a float 
or tied to a static line.
    Each hydrophone will be calibrated at the start of each action and 
will be checked frequently to the applicable standards of the 
hydrophone manufacturer. Environmental data will be collected, 
including but not limited to, the following: wind speed and direction, 
air temperature, humidity, surface water temperature, water depth, wave 
height, weather conditions, and other factors that could contribute to 
influencing the airborne and underwater sound levels (e.g., aircraft, 
boats, etc.). The chief inspector will supply the acoustics specialist 
with the substrate composition, hammer or drill model and size, hammer 
or drill energy settings and any changes to those settings during the 
piles being monitored, depth of the pile being driven or shaft 
excavated, and blows per foot for the piles monitored. For acoustically 
monitored piles and shafts, data from the monitoring locations will be 
post-processed to obtain the following sound measures:
     Maximum peak pressure level recorded for all the strikes 
associated with each pile or shaft, expressed in dB re 1 [mu]Pa. For 
pile driving and DTH mono-hammer excavation, this maximum value will 
originate from the phase of pile driving/drilling during which hammer/
drill energy was also at maximum (referred to as Level 4).
     From all the strikes associated with each pile occurring 
during the Level 4 phase these additional measures will be made:
    (1) mean, median, minimum, and maximum RMS pressure level in [dB re 
1 [mu]Pa];
    (2) mean duration of a pile strike (based on the 90 percent energy 
criterion);
    (3) number of hammer strikes;
    (4) mean, median, minimum, and maximum single strike SEL in [dB re 
[mu]Pa2 s];
     Cumulative SEL as defined by the mean single strike SEL + 
10*log10 (number of hammer strikes) in [dB re [mu]Pa2 s];
     Median integration time used to calculate SPL RMS;
     A frequency spectrum (pressure spectral density) in [dB re 
[mu]Pa2 per Hertz {Hz{time} ] based on the average of up to eight 
successive strikes with similar sound. Spectral resolution will be 1 
Hz, and the spectrum will cover nominal range from 7 Hz to 20 kHz;
     Finally, the cumulative SEL will be computed from all the 
strikes associated with each pile occurring during all phases, i.e., 
soft-start, Level 1 to Level 4. This measure is defined as the sum of 
all single strike SEL values. The sum is taken of the antilog, with 
log10 taken of result to express in [dB re [mu]Pa2 s].
    Hydro-acoustic monitoring will be conducted for at least 10 percent 
and up to 10 of each different pile type for each method of 
installation as shown in Table 13-1 in the application. All acoustic 
data will be analyzed after the project period for pile driving, rotary 
drilling, and DTH mono-hammer excavation events to confirm SPLs and 
rate of transmission loss for each construction activity.

Reporting

    OMAO will submit a draft marine mammal monitoring report to NMFS 
within 90 days after the completion of pile driving activities, or 60 
days prior to a requested date of issuance of any future IHAs for the 
project, or other projects at the same location, whichever comes first. 
The marine mammal monitoring report will include an overall description 
of work completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report will include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including:
    (1) The number and type of piles that were driven and the method 
(e.g., impact, vibratory, down-the-hole, etc.);
    (2) Total duration of time for each pile (vibratory driving) number 
of strikes for each pile (impact driving); and
    (3) For down-the-hole drilling, duration of operation for both 
impulsive and non-pulse components.
     PSO locations during marine mammal monitoring; and
     Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance.
    For each observation of a marine mammal, the following will be 
reported:
     Name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting;
     Time of sighting;
     Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
     Distance and location of each observed marine mammal 
relative to the pile being driven or hole being drilled for each 
sighting;
     Estimated number of animals (min/max/best estimate);
     Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
     Animal's closest point of approach and amount of time 
spent in harassment zone;
     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 implementation of any 
mitigation (e.g., shutdowns and delays), a description of specified 
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 
report will constitute the final report. If comments are received, a 
final report addressing NMFS' comments will be required to be submitted 
within 30 days after receipt of comments. All PSO

[[Page 78085]]

datasheets and/or raw sighting data will be submitted with the draft 
marine mammal report.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, OMAO will report the 
incident to the Office of Protected Resources (OPR) 
([email protected]), NMFS and to the Northeast Region 
(GARFO) regional stranding coordinator as soon as feasible. If the 
death or injury was clearly caused by the specified activity, OMAO will 
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 IHAs. OMAO will not resume their activities until notified by 
NMFS.
    The report will include the following information:
    1. Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    2. Species identification (if known) or description of the 
animal(s) involved;
    3. Condition of the animal(s) (including carcass condition if the 
animal is dead);
    4. Observed behaviors of the animal(s), if alive;
    5. If available, photographs or video footage of the animal(s); and
    6. General circumstances under which the animal was discovered.
    OMAO will also provide a hydro-acoustic monitoring report based 
upon hydro-acoustic monitoring conducted during construction 
activities. The hydro-acoustic monitoring report will include:
     Hydrophone equipment and methods: recording device, 
sampling rate, distance (meter) from the pile where recordings were 
made; depth of water and recording device(s);
     Type and size of pile being driven, substrate type, method 
of driving during recordings (e.g., hammer model and energy), and total 
pile driving duration;
     Whether a sound attenuation device is used and, if so, a 
detailed description of the device used and the duration of its use per 
pile;
     For impact pile driving and/or DTH mono-hammer excavation 
(per pile): Number of strikes and strike rate; depth of substrate to 
penetrate; pulse duration and mean, median, and maximum sound levels 
(dB re: 1 [mu]Pa): root mean square sound pressure level 
(SPLrms); cumulative sound exposure level 
(SELcum), peak sound pressure level (SPLpeak), 
and single-strike sound exposure level (SELs-s);
     For vibratory driving/removal and/or DTH mono-hammer 
excavation (per pile): Duration of driving per pile; mean, median, and 
maximum sound levels (dB re: 1 [mu]Pa): root mean square sound pressure 
level (SPLrms), cumulative sound exposure level 
(SELcum) (and timeframe over which the sound is averaged);
     One-third octave band spectrum and power spectral density 
plot; and
     General daily site conditions, including date and time of 
activities, water conditions (e.g., sea state, tidal state), and 
weather conditions (e.g., percent cover, visibility.

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 majority of our analysis applies to all 
the species listed in Table 1, given that many of the anticipated 
effects of this project on different marine mammal stocks are expected 
to be relatively similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, they are described independently in the analysis below.
    Pile driving activities associated with the OMAO vessel relocation 
project have the potential to disturb or displace marine mammals. 
Specifically, the project activities may result in take, in the form of 
Level B harassment, and for harbor porpoise, harbor seal, gray seal, 
and harp seal, Level A harassment, from underwater sounds generated 
from pile driving and removal, DTH, and rotary drilling. Potential 
takes could occur if individuals are present in zones ensonified above 
the thresholds for Level B harassment, identified above, when these 
activities are underway.
    No serious injury or mortality is expected, even in the absence of 
required mitigation measures, given the nature of the activities. 
Further, no take by Level A harassment is anticipated for Atlantic 
white-sided dolphins, short-beaked common dolphins, and harp seals due 
to the application of planned mitigation measures, such as shutdown 
zones that encompass the Level A harassment zones for these species. 
The potential for harassment will be minimized through the construction 
method and the implementation of the planned mitigation measures (see 
Mitigation section).
    Take by Level A harassment is authorized for four species (harbor 
porpoise, harbor seal, gray seal, and harp seal) as the Level A 
harassment zones exceed the size of the shutdown zones for specific 
construction scenarios. Therefore, there is the possibility that an 
animal could enter a Level A harassment zone without being detected, 
and remain within that zone for a duration long enough to incur PTS. 
Any take by Level A harassment is expected to arise from, at most, a 
small degree of PTS (i.e., minor degradation of hearing capabilities 
within regions of hearing that align most completely with the energy 
produced by impact pile driving such as the low-frequency region below 
2 kHz), not severe hearing impairment or impairment within the ranges 
of greatest hearing sensitivity. Animals would need to be exposed to 
higher levels and/or longer duration than are expected to occur here in 
order to incur any more than a small degree of PTS.
    Further, the amount of take authorized by Level A harassment is 
very low for all marine mammal stocks and species. For three species, 
Atlantic white-sided dolphin, short-beaked common dolphin, and harp 
seal, NMFS

[[Page 78086]]

neither anticipates nor authorized Level A harassment take over the 
duration of OMAO's planned activities; for the other four stocks, NMFS 
authorized no more than 56 takes by Level A harassment for any stock. 
If hearing impairment occurs, it is most likely that the affected 
animal would lose only a few decibels in its hearing sensitivity. Due 
to the small degree anticipated, any PTS potential incurred would not 
be expected to affect the reproductive success or survival of any 
individuals, much less result in adverse impacts on the species or 
stock.
    Additionally, some subset of the individuals that are behaviorally 
harassed could also simultaneously incur some small degree of TTS for a 
short duration of time. However, since the hearing sensitivity of 
individuals that incur TTS is expected to recover completely within 
minutes to hours, it is unlikely that the brief hearing impairment 
would affect the individual's long-term ability to forage and 
communicate with conspecifics, and will therefore not likely impact 
reproduction or survival of any individual marine mammal, let alone 
adversely affect rates of recruitment or survival of the species or 
stock.
    As described above, NMFS expects that marine mammals will likely 
move away from an aversive stimulus, especially at levels that would be 
expected to result in PTS, given sufficient notice through use of soft 
start. OMAO will also shut down pile driving activities if marine 
mammals enter the shutdown zones (see Table 12) further minimizing the 
likelihood and degree of PTS that would be incurred.
    Effects on individuals that are taken by Level B harassment in the 
form of behavioral disruption, on the basis of reports in the 
literature as well as monitoring from other similar activities, will 
likely be limited to reactions such as avoidance, increased swimming 
speeds, increased surfacing time, or decreased foraging (if such 
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely, 
individuals will simply move away from the sound source and temporarily 
avoid the area where pile driving is occurring. If sound produced by 
project activities is sufficiently disturbing, animals are likely to 
simply avoid the area while the activities are occurring. We expect 
that any avoidance of the project areas by marine mammals will be 
temporary in nature and that any marine mammals that avoid the project 
areas during construction will not be permanently displaced. Short-term 
avoidance of the project areas and energetic impacts of interrupted 
foraging or other important behaviors is unlikely to affect the 
reproduction or survival of individual marine mammals, and the effects 
of behavioral disturbance on individuals is not likely to accrue in a 
manner that will affect the rates of recruitment or survival of any 
affected stock.
    Since June 2022, an Unusual Mortality Event (UME) has been declared 
for Northeast pinnipeds in which elevated numbers of sick and dead 
harbor seals and gray seals have been documented along the southern and 
central coast of Maine (NOAA Fisheries, 2022). Currently, 25 gray seals 
and 258 harbor seals have stranded. However, we do not expect the takes 
authorized by this IHA to exacerbate or compound upon this ongoing UME. 
As noted previously, no non-auditory injury, serious injury, or 
mortality is expected or authorized, and takes of harbor seal and gray 
seal will be reduced to the level of least practicable adverse impact 
through the incorporation of the required mitigation measures. For the 
WNA stock of gray seal, the estimated U.S. stock abundance is 27,300 
animals (estimated 424,300 animals in the Canadian portion of the 
stock). Given that only 448 takes are authorized for this stock, we do 
not expect this authorization to exacerbate or compound upon the 
ongoing UME. For the WNA stock of harbor seals, the estimated abundance 
is 61,336 individuals. The estimated M/SI for this stock (339) is well 
below the PBR (1,729) (Hayes et al., 2020). As such, the authorized 
takes of harbor seal are not expected to exacerbate or compound upon 
the ongoing UME.
    The project is also not expected to have significant adverse 
effects on affected marine mammals' habitats. No ESA-designated 
critical habitat or biologically important areas (BIAs) are located 
within the project area. The project activities will not modify 
existing marine mammal habitat for a significant amount of time. The 
activities may cause a low level of turbidity in the water column and 
some fish may leave the area of disturbance, thus temporarily impacting 
marine mammals' foraging opportunities in a limited portion of the 
foraging range; but, because of the short duration of the activities 
and the relatively small area of the habitat that may be affected (with 
no known particular importance to marine mammals), the impacts to 
marine mammal habitat are not expected to cause significant or long-
term negative consequences. Seasonal nearshore marine mammal surveys 
were conducted at NAVSTA Newport from May 2016 to February 2017, and 
several harbor seal haul outs were identified in Narragansett Bay, but 
no pupping was observed.
    For all species and stocks, take will occur within a limited, 
relatively confined area (Coddington Cove) of the stock's range. Given 
the availability of suitable habitat nearby, any displacement of marine 
mammals from the project areas is not expected to affect marine 
mammals' fitness, survival, and reproduction due to the limited 
geographic area that will be affected in comparison to the much larger 
habitat for marine mammals within Narragansett Bay and outside the bay 
along the Rhode Island coasts. Level A harassment and Level B 
harassment will be reduced to the level of least practicable adverse 
impact to the marine mammal species or stocks and their habitat through 
use of mitigation measures described herein.
    Some individual marine mammals in the project area, such as harbor 
seals, may be present and be subject to repeated exposure to sound from 
pile driving activities on multiple days. However, pile driving and 
extraction is not expected to occur on every day, and these individuals 
will likely return to normal behavior during gaps in pile driving 
activity within each day of construction and in between workdays. As 
discussed above, there is similar transit and haul out habitat 
available for marine mammals within and outside of the Narragansett Bay 
along the Rhode Island coast, outside of the project area, where 
individuals could temporarily relocate during construction activities 
to reduce exposure to elevated sound levels from the project. 
Therefore, any behavioral effects of repeated or long duration 
exposures are not expected to negatively affect survival or 
reproductive success of any individuals. Thus, even repeated Level B 
harassment of some small subset of an overall stock is unlikely to 
result in any effects on rates of reproduction and survival of the 
stock.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     No Level A harassment of Atlantic white-sided dolphins, 
short-beaked common dolphins, or harp seals is authorized;
     The small Level A harassment takes of harbor porpoises, 
harbor seals, gray seals, and hooded seals authorized are expected to 
be of a small degree;

[[Page 78087]]

     The intensity of anticipated takes by Level B harassment 
is relatively low for all stocks. Level B harassment will be primarily 
in the form of behavioral disturbance, resulting in avoidance of the 
project areas around where impact or vibratory pile driving is 
occurring, with some low-level TTS that may limit the detection of 
acoustic cues for relatively brief amounts of time in relatively 
confined footprints of the activities;
     Nearby areas of similar habitat value (e.g., transit and 
haul out habitats) within and outside of Narragansett Bay are available 
for marine mammals that may temporarily vacate the project area during 
construction activities;
     The specified activity and associated ensonified areas do 
not include habitat areas known to be of special significance (BIAs or 
ESA-designated critical habitat);
     Effects on species that serve as prey for marine mammals 
from the activities are expected to be short-term and, therefore, any 
associated impacts on marine mammal feeding are not expected to result 
in significant or long-term consequences for individuals, or to accrue 
to adverse impacts on their populations;
     The ensonified areas are very small relative to the 
overall habitat ranges of all species and stocks, and will not 
adversely affect ESA-designated critical habitat for any species or any 
areas of known biological importance;
     The lack of anticipated significant or long-term negative 
effects to marine mammal habitat; and
     The efficacy of the mitigation measures in reducing the 
effects of the specified activities on all species and stocks.
    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 monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the planned 
activity will have a negligible impact on all affected marine mammal 
species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take 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 number of individuals taken 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 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.
    The instances of take NMFS proposes to authorize is below one-third 
of the estimated stock abundance for all impacted stocks (Table 12). 
(In fact, take of individuals is less than 4 percent of the abundance 
for all affected stocks.) The number of animals that we are authorizing 
to be taken is considered small relative to the relevant stocks or 
populations, even if each estimated take occurred to a new individual. 
Furthermore, these takes are likely to only occur within a small 
portion of the each stock's range and the likelihood that each take 
will occur to a new individual is low.
    Based on the analysis contained herein of the planned activity 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS finds that small numbers of marine mammals 
will 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 will not 
have an unmitigable adverse impact on the availability of such species 
or stocks for taking for subsistence purposes.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is authorized or expected 
to result from this activity. Therefore, NMFS has determined that 
formal consultation under section 7 of the ESA is not required for this 
action.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
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 NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for 
significant impacts on the quality of the human environment and for 
which we have not identified any extraordinary circumstances that would 
preclude this categorical exclusion. Accordingly, NMFS has determined 
that the issuance of the IHA qualifies to be categorically excluded 
from further NEPA review.

Authorization

    NMFS has issued an IHA to OMAO for the potential harassment of 
small numbers of seven marine mammal species incidental to construction 
activities at Naval Station Newport, in Newport, RI, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are followed.

    Dated: December 15, 2022.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2022-27727 Filed 12-20-22; 8:45 am]
BILLING CODE 3510-22-P