Notice2022-27727
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
Primary source
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Published
December 21, 2022
Effective
February 1, 2024
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 87 Issue 244 (Wednesday, December 21, 2022)</title>
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[Federal Register Volume 87, Number 244 (Wednesday, December 21, 2022)]
[Notices]
[Pages 78072-78087]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. 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;
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>.)
Table 1 lists all species or stocks for which take is 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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>).
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
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; 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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments/">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments/</a> 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 (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) 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:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
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 * log<INF>10</INF> (R<INF>1</INF>/R<INF>2</INF>),
Where
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement.
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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Marine mammal monitoring during in-water construction activities
will be conducted by PSOs meeting NMFS' standards and in a manner
consistent with the following:
<bullet> 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;
<bullet> 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;
<bullet> Other PSOs may substitute education (degree in biological
science or related field) or training for experience; and
<bullet> 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:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including, but not limited to, 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
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
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:
<bullet> 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).
<bullet> 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];
<bullet> Cumulative SEL as defined by the mean single strike SEL +
10*log10 (number of hammer strikes) in [dB re [mu]Pa2 s];
<bullet> Median integration time used to calculate SPL RMS;
<bullet> 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;
<bullet> 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:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> 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.
<bullet> PSO locations during marine mammal monitoring; and
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance.
For each observation of a marine mammal, the following will be
reported:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting;
<bullet> Time of sighting;
<bullet> 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;
<bullet> Distance and location of each observed marine mammal
relative to the pile being driven or hole being drilled for each
sighting;
<bullet> Estimated number of animals (min/max/best estimate);
<bullet> Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
<bullet> Animal's closest point of approach and amount of time
spent in harassment zone;
<bullet> Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching);
<bullet> Number of marine mammals detected within the harassment
zones, by species; and
<bullet> Detailed information about 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)
(<a href="/cdn-cgi/l/email-protection#e8b8bac6a1bcb8c6a58786819c879a81868fba8d98879a9c9ba886878989c68f879e"><span class="__cf_email__" data-cfemail="9ececcb0d7caceb0d3f1f0f7eaf1ecf7f0f9ccfbeef1eceaeddef0f1ffffb0f9f1e8">[email protected]</span></a>), 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:
<bullet> Hydrophone equipment and methods: recording device,
sampling rate, distance (meter) from the pile where recordings were
made; depth of water and recording device(s);
<bullet> 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;
<bullet> 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;
<bullet> 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
(SPL<INF>rms</INF>); cumulative sound exposure level
(SEL<INF>cum</INF>), peak sound pressure level (SPL<INF>peak</INF>),
and single-strike sound exposure level (SEL<INF>s-s</INF>);
<bullet> 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 (SPL<INF>rms</INF>), cumulative sound exposure level
(SEL<INF>cum</INF>) (and timeframe over which the sound is averaged);
<bullet> One-third octave band spectrum and power spectral density
plot; and
<bullet> 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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> No Level A harassment of Atlantic white-sided dolphins,
short-beaked common dolphins, or harp seals is authorized;
<bullet> 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]]
<bullet> 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;
<bullet> 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;
<bullet> The specified activity and associated ensonified areas do
not include habitat areas known to be of special significance (BIAs or
ESA-designated critical habitat);
<bullet> 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;
<bullet> 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;
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and
<bullet> 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
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