Notice2021-11983
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Portsmouth Naval Shipyard Dry Dock 1 Modification and Expansion
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
June 8, 2021
Effective
June 2, 2021
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 IHA to the U.S. Navy (Navy) to incidentally harass, by Level B and Level A harassment, marine mammals incidental to Portsmouth Naval Shipyard (PNSY) Dry Dock 1 (DD1) modification and expansion in Kittery, Maine.
Full Text
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<title>Federal Register, Volume 86 Issue 108 (Tuesday, June 8, 2021)</title>
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[Federal Register Volume 86, Number 108 (Tuesday, June 8, 2021)]
[Notices]
[Pages 30418-30434]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-11983]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XB146]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Portsmouth Naval Shipyard Dry Dock
1 Modification and Expansion
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of 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 IHA to the U.S. Navy (Navy) to incidentally
harass, by Level B and Level A harassment, marine mammals incidental to
Portsmouth Naval Shipyard (PNSY) Dry Dock 1 (DD1) modification and
expansion in Kittery, Maine.
DATES: This authorization is effective from June 2, 2021 through June
1, 2022.
FOR FURTHER INFORMATION CONTACT: Carter Esch, Office of Protected
Resources, NMFS, (301) 427-8421. 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</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
[[Page 30419]]
issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be 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 such species or stocks for
taking for certain subsistence uses (referred to here as
``mitigation''). Monitoring and reporting of such takings are also
required. The meaning of key terms such as ``take,'' ``harassment,''
and ``negligible impact'' can be found in section 3 of the MMPA (16
U.S.C. 1362 and the agency's regulations at 50 CFR 216.103.
Summary of Request
On October 22, 2020, NMFS received a request from the Navy for an
IHA to take marine mammals incidental to modification and expansion of
DD1 at PNSY in Kittery, Maine. The Navy submitted revised versions of
the application on December 30, 2020, and January 19 and February 11,
2021. The application was deemed adequate and complete on February 19,
2021. The Navy's request is for take of a small number of harbor
porpoises, harbor seals, gray seals, harp seals, and hooded seals by
Level B harassment and Level A harassment for a subset of these
species. Neither the Navy nor NMFS expects serious injury or mortality
to result from this activity; therefore, an IHA is appropriate.
NMFS previously issued three IHAs to the Navy for waterfront
improvement work, in 2016 (81 FR 85525; November 28, 2016), 2018 (83 FR
3318; January 24, 2018), 2019 (84 FR 24476, May 28, 2019), and a
renewal of the 2019 IHA (86 FR 14598; March 17, 2021). As required, the
applicant provided monitoring reports (available 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>) which confirm that the
applicant has implemented the required mitigation and monitoring, and
which also shows that no impacts of a scale or nature not previously
analyzed or authorized have occurred as a result of the activities
conducted. This IHA covers the second year of a larger five-year
project, for which the Navy also intends to request take authorization
for subsequent dock modification and expansion at the PNSY.
Description of the Specified Activity
As part of its overall objective to modernize and maximize dry dock
capabilities for performing current and future missions efficiently and
with maximum flexibility, the Navy plans to modify and expand DD1 at
the PNSY by constructing two new dry docking positions capable of
servicing Virginia class submarines within the super flood basin of the
dry dock. The in-water portion of the dock modification and expansion,
which will occur within and at the boundaries of the super flood basin,
includes: Construction of the west closure wall, construction of
entrance structure closure walls, and bedrock excavation. Construction
activities include in-water impact pile driving, vibratory pile driving
and removal, rock drilling, and underwater blasting. Underwater sounds
produced by these activities may result in Level B harassment and Level
A harassment of marine mammal species.
In-water construction activities are expected to occur between June
2021 and June 2022, with an estimated total of 29 days for pile driving
and pile removal, 130 days for drilling of blast charge holes, and 130
days of blasting for bedrock excavation, for a total of 289
construction days. Some of these activities will occur on the same day,
resulting in 159 total construction days over 12 months. However, as a
conservative measure, construction days are accounted for as
consecutive rather than concurrent activities in take estimates (see
Estimated Take section). All in-water construction work will be limited
to daylight hours, with the exception of pre-dawn (beginning no earlier
than 3:00 a.m.) drilling of blast charge holes; drilling will not occur
from sunset to pre-dawn. The daily construction timeframe for blasting
will begin no sooner than 30 minutes after sunrise to allow for initial
marine mammal monitoring to take place and will end at least 60 minutes
before sunset to allow for post-activity monitoring.
A summary of in-water pile driving activity is provided in Table 1.
In addition, a total of 1,580, 4.5-inch blast charge holes will be
drilled at a rate of 12 holes per day over 130 days. The Navy
anticipates one to two blast events per day, with a maximum of 6 blast
events per week; a total of 150 blast events will occur over 130 days.
Table 1--Summary of In-Water Pile Driving Activities
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Pile size
Pile purpose Pile type (inch) Pile drive method Total piles Piles/day Work days
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West closure wall template........... Steel pipe.............. 30 Vibratory.............. 13 installed........... 3 5
13 removed............. 3 5
West closure wall construction....... Flat-webbed steel sheet. 18 Vibratory.............. 160.................... 12 13
Impact.................
Entrance structure temporary guide Steel pipe.............. 30 Vibratory.............. 12..................... 8 2
dolphin removal.
Entrance structure closure wall Steel sheet............. 28 Vibratory.............. 44..................... 12 4
construction.
Impact.................
------------- --------------------------------------------------
Total............................ ........................ ........... ....................... 242.................... ........... 29
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Construction activities will occur at the PNSY in Kittery, Maine.
Please see Figures 1-1 to 1-6 in the Navy's IHA application for
detailed maps of the project area and super flood basin. A detailed
description of the planned modification and expansion of DD1 is
provided in the Federal Register notice for the proposed IHA (86 FR
18244; April 8, 2021). Since that time, no changes have been made to
the planned activities. Therefore, a detailed
[[Page 30420]]
description is not provided here. Please refer to that Federal Register
notice and the original proposed IHA documents referenced therein for a
detailed description of the specified activity.
Comments and Responses
A notice of NMFS' proposal to issue an IHA to the Navy was
published in the Federal Register on April 8, 2021 (86 FR 18244). That
notice described, in detail, the Navy'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,
NMFS received comments from the Marine Mammal Commission (Commission).
For full details of the comments, please see the Commission's letter,
which is available online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities#active-authorizations">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities#active-authorizations</a>. A summary of the Commission's
recommendations as well as NMFS' responses is below.
Comment 1: As a result of its belief that NMFS did not provide the
public with an adequate basis for review of NMFS' proposed action, due
to what it asserts are errors in the notice of the proposed
authorization, the Commission recommends that NMFS either deny the
proposed incidental harassment authorization or publish a revised
Federal Register notice and draft authorization with another 30-day
comment period.
Response: NMFS does not agree with the Commission and does not
adopt the recommendation. Although the initial Federal Register notice
and proposed authorization contained certain errors and omissions,
which have been addressed in this notice and authorization according to
the Commission's recommendations, the description of the specified
activity and analysis of potential acoustic impacts on marine mammals
in the vicinity of the project area in the notice of the proposed
authorization (86 FR 18422; April 8, 2021) provided sufficient
information upon which to determine whether or not the activities would
have a negligible impact on the species or stocks for which take is
likely to occur, and on which the public had an opportunity to comment.
The information utilized in take estimation (i.e., source levels,
thresholds, densities, and number of construction days for each
specified activity) has largely been retained from the proposed to the
final authorization, with the exception of revised source levels for
impact pile driving of an 18-inch flat-webbed sheet pile (which reduced
the harassment zone sizes and take estimates for gray and harbor
seals). The Commission noted that the thresholds associated with slight
lung injury and mortality were incorrectly specified in the notice of
the proposed IHA. However, the distances to the isopleths for onset of
and 50 percent probability of gastrointestinal tract injury, and the
resulting estimate of zero take for harbor porpoises and phocids,
provided accurate information regarding the potential for this type of
non-auditory injury. The distances to thresholds associated with
gastrointestinal injury (harbor porpoises, 26 meters (m); phocids, 26
m), slight lung injury (harbor porpoises, 48 meters; phocids, 34 m) and
mortality (harbor porpoises, 21 m; phocids, 18 m) calculated for the
City of Juneau's Statter Harbor Project (see 84 FR 11066; March 25,
2019) are similar to each other in magnitude. The distances to slight
lung injury and mortality thresholds are not expected to be
substantially different for blasting at PNSY than those calculated for
Statter Harbor, and would likely be within tens of meters from those
estimated here for onset of and 50 percent probability of
gastrointestinal tract injury. All of these zones would be smaller than
the Level A harassment zones for harbor porpoises and phocids, and
would be encompassed by the large shutdown zone for blasting at DD1.
The mitigation requirements for blasting events, including the use of
stemmed charges, installation of a double bubble curtain across
openings to the super flood basin in which blasting will occur, and
implementation of shutdown procedures, are sufficiently protective to
minimize the potential for non-auditory injury such that the potential
for non-auditory injury is considered discountable. No mortality is
anticipated or authorized for these activities. Per the Commission's
recommendations, additional mitigation and monitoring requirements for
blasting have been incorporated into the issued authorization.
The majority of the Commission's comments pertained to errors or
inconsistencies that have been addressed in this notice and the final
authorization. NMFS' small numbers finding and negligible impact
determination were not affected by the changes from the proposed to the
final authorization; therefore, NMFS is not republishing a notice of
the proposed authorization.
Comment 2: The Commission recommends that NMFS return the IHA
application to the Navy as incomplete and refrain from processing
future authorization applications until the Commission's perceived
issues are resolved.
Response: NMFS appreciates the Commission's concern but will
consider any future requests for incidental take authorization from the
Navy according to the requirements of the MMPA.
Changes From the Proposed IHA to the Final IHA
The following corrections and additions have been incorporated into
this notice and/or the issued IHA:
<bullet> Corrected the reference for the 28-inch Z-shaped sheet
pile source level (NAVFAC 2020; Table 6);
<bullet> Revised source levels for impact pile driving of 18-inch
flat-webbed sheet piles, as well as all associated acoustic analyses
and take estimation;
<bullet> Included a description of transmission loss modeling, as
well as the coefficients used to estimate Level B harassment zones for
construction activities;
<bullet> Included the input parameters used to estimate Level A
harassment zones for pile driving and removal, and blast-charge hole
drilling (Table 8);
<bullet> Corrected distance to the Level B harassment isopleth for
removal of 30-inch steel pipe piles to 13.6 kilometers (km) from 46 km
(Table 8);
<bullet> Corrected typographical errors specifying ensonified zones
in Tables 8 and 9;
<bullet> Included ranges to peak SPL thresholds for PTS for
blasting events as a footnote of Table 9;
<bullet> Refined identification of the specific activities to which
take is attributed (Table 11);
<bullet> Corrected take estimate for harbor porpoises (reduced from
6 to 4) to align with the IHA application, and adjusted take estimates
for impact pile driving of 18-inch flat-webbed sheet piles based on
revised source levels (Table 11);
<bullet> Added additional mitigation requirements for blasting,
including (1) requiring stemmed charges, (2) restricting blasting to a
time period at least 30 minutes after sunrise and one hour before
sunset, (3) requiring monitoring to occur for at least one hour after
blasting activities cease, (4) requiring that the Navy notify NMFS and
the Greater Atlantic Regional Stranding Coordinator or local stranding
network at least 24 hours prior to commencing a blasting event and
within 24 hours after a blasting event ceases (if occurring on
consecutive days, the Navy can provide notice of how long blasting is
scheduled to last and when it has been completed), and (5) requiring
that the Navy immediately report any injured or dead marine mammal to
the
[[Page 30421]]
Greater Atlantic Regional Stranding Coordinator or local stranding
network and follow any instructions provided by the Stranding
Coordinator or stranding network;
<bullet> Clarified the number and potential locations of Protected
Species Observers (PSOs);
<bullet> Clarified that pile driving/removal must only occur during
daylight hours;
<bullet> Clarified in this notice that 10, 18-inch flat-webbed
piles will be acoustically monitored during vibratory and impact pile
driving, and 4, 30-inch steel piles will be monitored during vibratory
pile driving, as was included in the draft IHA;
<bullet> Added hydroacoustic monitoring plan, which can be accessed
at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities#active-authorizations">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities#active-authorizations</a>;
<bullet> Corrected contact information and requirements for
reporting a dead or injured marine mammal to provide consistency
between this notice and the IHA;
<bullet> Clarified that the IHA condition 4(e) applies to all
activities; and
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.
Additional information regarding population trends and threats may be
found in NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website: (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists the five marine mammal species, including one
cetacean and four pinnipeds, with the potential to occur in the area of
the specified activity and for which take is authorized for this
action, and summarizes information related to the population or stock,
including regulatory status under the MMPA and ESA and potential
biological removal (PBR), where known. For taxonomy, NMFS follows
Committee on Taxonomy (2020). 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 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 for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Atlantic Marine Mammal SARs. All values presented in Table 2
are the most recent available at the time of publication and are
available in the final 2019 SARs (Hayes et al., 2020) and draft 2020
SARs, 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 2--Marine Mammals With Potential Presence Within the Project Area
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales)
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Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -; N 95,543 (0.31; 74,034; 851 217
Fundy. 2016).
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Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Western North Atlantic. -; N 75,834 (0.15, 66,884; 2,006 350
2012).
Gray seal....................... Halichoerus grypus..... Western North Atlantic. -; N 27,131 \4\ (0.19; 1,389 4,729
23,158; 2016).
Harp seal....................... Pagophilus Western North Atlantic. -; N Unknown (NA, NA)...... unk 232,422
groenlandicus.
Hooded seal..................... Cystophora cristata.... Western North Atlantic. -; N Unknown (NA, NA)...... unk 1,680
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\1\ 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.
\2\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region#reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region#reports</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
with estimated mortality due to commercial fisheries is presented in some cases.
\4\ NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 451,431. The PBR value presented is in
relation to the U.S. population, whereas the annual M/SI value is for the entire stock.
Detailed descriptions of the species likely to be affected by the
Navy's 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 notice of the proposed IHA (86 FR 18244; April 8,
2021). Since that time, NMFS is not aware of any substantive new
information regarding these species or stocks; therefore, detailed
descriptions are not provided here. Please refer to that notice for
descriptions. Please also refer to NMFS' website
(<a href="http://www.fisheries.noaa.gov/find-species">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
[[Page 30422]]
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. Current data indicate that 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) recommended that marine mammals be
divided into functional hearing groups based on directly measured or
estimated hearing ranges on the basis of available behavioral response
data, audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. 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 3.
Table 3--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
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.
As mentioned previously, five marine mammal species (one cetacean and
four pinniped (all phocid) species) have the reasonable potential to
co-occur with the construction activities. Please refer to Table 2. The
only cetacean species that may be present, the harbor porpoise, is
classified as a high-frequency cetacean.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from impact pile driving, vibratory
pile driving and removal, drilling, and blasting activities for the
Navy's modification and expansion of DD1 have the potential to result
in Level B harassment (behavioral disturbance, TTS) for marine mammal
species authorized for take. Level A harassment (injury) in the form of
PTS may also occur in limited numbers of animals. No other forms of
Level A harassment would occur, nor would serious injury or mortality.
The project would not result in permanent impacts to habitats used
directly by marine mammals, such as haulout sites, but may have
potential short-term impacts to food sources such as forage fish and
impacts to the substrate during installation and removal of piles and
as a result of bedrock removal. The Federal Register notice of the
proposed IHA (86 FR 18244; April 8, 2021) included a discussion of the
potential effects to marine mammals and their associated habitat,
therefore, that information is not repeated here; please refer to the
notice of proposed IHA for more details.
Estimated Take
This section provides an estimate of the number of incidental takes
authorized by the IHA, which informed both NMFS' consideration of
``small numbers'' and the negligible impact determination.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be primarily by Level B behavioral
harassment, as noise generated from in-water pile driving (vibratory
and impact), drilling, and blasting has the potential to result in
disruption of behavioral patterns for individual marine mammals. The
use of the explosive source (i.e., blasting) for a very short period
each day has the potential to result in Temporary Threshold Shift
(TTS), which is another form of Level B harassment. There is also some
potential for auditory injury (Level A harassment) to result from
impact pile driving and blasting in the form of Permanent Threshold
Shift (PTS). The required mitigation and monitoring measures (see
Mitigation Requirements and Monitoring and Reporting Requirements
sections) are expected to minimize the severity of such taking to the
extent practicable.
The primary relevant mitigation measure to minimize Level A
harassment is delaying these activities, to the extent practicable,
when any marine mammal is observed in the Level A harassment zones for
PTS. While this requirement is expected to minimize take by Level A
harassment, NMFS is authorizing takes by Level A harassment (in the
form of PTS) to account for the possibility that marine mammals escape
observation in the PTS zone and because the shutdown zones (see
Mitigation Requirements section) are, in most cases, smaller than the
Level A harassment zones. The distances to thresholds associated with
the onset of and 50 percent probability of injury to the
gastrointestinal tract for harbor porpoises (5 meters (m)) and phocids
(9
[[Page 30423]]
m) are small enough that the mitigation and monitoring measures are
expected to avoid the potential for such taking. As mentioned
previously, distances to thresholds for slight lung injury and
mortality are not modeled here, but are expected to have a similar
small magnitude and range of values (tens of meters) as those reported
for the Statter Harbor project (84 FR 11066; March 25, 2019). In
conjunction with small zone sizes for onset of and 50 percent
probability of gastrointestinal tract injury and NMFS' expectation that
zone sizes for slight lung injury will be small, blasting will occur in
a confined area that allows for effective observation with only one
entrance to the basin that will be blocked by a bubble curtain during
blasting events, within a large shutdown zone equivalent to the Level A
harassment zone for harbor porpoises, all of which make it unlikely
that these types of non-auditory injuries will occur. Therefore, the
potential for non-auditory physical injury is considered discountable,
and any takes by Level A harassment are expected to occur due to PTS.
As described previously, no mortality is anticipated or authorized
for these activities. The method by which take is estimated is
described below.
Generally speaking, NMFS estimates take by considering: (1)
Acoustic thresholds above which NMFS believes 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) and the number of days
of activities. NMFS notes that while these basic factors can contribute
to a basic calculation to provide an initial prediction of takes,
additional information that can qualitatively inform take estimates is
also sometimes available (e.g., previous monitoring results or average
group size). Below, NMFS describes the factors considered here in more
detail and presents the authorized take.
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 or experience
TTS (equated to Level B harassment), or to incur PTS of some degree
(equated to Level A harassment). Thresholds have also been developed to
identify the pressure levels above which animals may incur different
types of tissue damage from exposure to pressure waves from explosive
detonations.
Level B Harassment for non-explosive sources--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 (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner NMFS considers Level B
behavioral harassment when exposed to underwater anthropogenic noise
above received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g.,
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms)
for impulsive and/or intermittent (e.g., impact pile driving) sources.
The Navy's Portsmouth Naval Shipyard modification and expansion
project includes the use of continuous, or non-impulsive, (i.e.,
vibratory pile driving and drilling) and impulsive (i.e., impact pile
driving) sources; therefore, the 120 and 160 dB re 1 [mu]Pa (rms)
thresholds are appropriate.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (NMFS, 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).
As noted above, the Navy's planned activity includes the use of
impulsive and non-impulsive sources.
These thresholds are provided in Table 4. 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="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (HF cetaceans and PW pinnipeds) and that the
recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be exceeded
in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is
valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Explosive sources--Based on the best available science, NMFS uses
the acoustic and pressure thresholds indicated in Table 5 to predict
the onset of behavioral harassment, PTS, and non-auditory impacts.
Because of the instantaneous nature of blasting, there is no
established Level B behavioral harassment threshold associated with
[[Page 30424]]
the activity. A single detonation is not likely to disrupt behavioral
patterns beyond a brief startle response, therefore, the 160 dB re 1
[mu]Pa (rms) threshold for behavioral harassment from impulsive
acoustic sources is not applicable. However, TTS, which (as mentioned
previously) is a form of Level B harassment take, may occur. The
behavioral threshold used in analyses for multiple explosive events is
determined relative to (5 dB less than) the TTS onset threshold (DoN
2017). The threshold associated with the onset of effect for non-
auditory injury to the gastrointestinal tract (237 dB re 1 [mu]Pa
(peak)) is used to determine the distances at which there is a one
percent likelihood of injury occurring, informing mitigation measures
rather than take estimates (DoN 2017). Take estimates are based on the
243 dB re 1 [mu]Pa (peak) threshold, the criterion used to predict the
distances at which there is a 50 percent probability of
gastrointestinal injury resulting from underwater explosions (DoN
2017). During the public comment period, the Marine Mammal Commission
noted that the thresholds for slight lung injury and mortality were
incorrectly specified in the notice of the proposed IHA. However, the
distances to isopleths associated with the onset of and 50 percent
probability of gastrointestinal injury were correctly modeled,
resulting in very small zone sizes, and the zone sizes for slight lung
injury and mortality (although not presented here) are expected to be
commensurate with those modeled for the City of Juneau's Statter Harbor
project (84 FR 11066; March 25, 2019), given that both projects (1)
analyze acoustic impacts of confined blasting in drill shafts in
underwater bedrock within a harbor/basin, (2) utilize the same sound
exposure level for blasting events, and (3) estimate transmission loss
by combining spherical spreading with frequency-specific absorption
loss to the environment. The size of the shutdown zone for blasting,
relative to these small zones, is sufficiently large to discount the
potential for this type of injury. The shutdown zone for blasting
equates to the Level A harassment zone for harbor porpoises, which is a
0.335 square kilometers (km\2\) arc-shaped area that encompasses the
super flood basin and extends into the Piscataqua River (show in Figure
6-5 of the IHA application). This shutdown zone fully encompasses the
Level A harassment zone for phocids (0.01978 km\2\), and onset of
(0.000254 km\2\) and 50 percent probability of (0.0008 km\2\)
gastrointestinal injury zone, Further, the Navy will not begin blasting
activities until one sheet pile face of the west closure wall is
installed, thus providing an additional barrier to sound propagating
into the environment beyond the super flood basin (reducing the maximum
ensonified zone from 0.418 km\2\ to 0.335 km\2\). In addition, the Navy
will install a double bubble curtain at the entrance to the super flood
basin during blasting and drilling activities within the basin, the
attenuation from which (although not incorporated into the acoustic
analyses presented here) will further reduce the impact of sound
produced during these activities. 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.nmfs.noaa.gov/pr/acoustics/guidelines.htm">http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm</a>.
Table 5--Explosive Acoustic and Pressure Thresholds for Marine Mammals
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B harassment Level A harassment Non-auditory
----------------------------------------------------------------------------------------------------------------------
Group Behavioral (multiple Gastro-intestinal tract Gastro-intestinal tract
detonations) TTS PTS (onset of effect) (injury)
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-Frequency (HF) Cetaceans.... 135 dB SEL............. 140 dB SEL or 196 155 dB SEL or 202 237 dB SPLpk............ 243 dB SPLpk
dB SPLpk. dB SPLpk.
Phocid Pinnipeds (PW) 165 dB SEL............. 170 dB SEL or 212 185 dB SEL or 218
(Underwater). dB SPLpk. dB SPLpk.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ensonified Area
The operational and environmental parameters of the activity that
fed into identifying the area ensonified above the acoustic thresholds,
which include source levels and transmission loss, are described below.
Source Levels
The project includes impact pile driving, vibratory pile driving
and pile removal, drilling, and blasting. Of these, only drilling and
vibratory pile driving will occur concurrently. When two continuous
noise sources have overlapping sound fields, there is a potential for
higher sound levels (and a larger associated ensonified zone) than for
non-overlapping sources. When drilling and vibratory pile driving co-
occur, the larger of the two shutdown zones will trigger mitigation
measures.
Source levels of pile driving activities are based on reviews of
measurements of the same or similar types and dimensions of piles
available in the literature. Source levels for impact pile driving of a
30-inch steel pipe pile are used as a proxy for impact driving of 28-
inch Z-shaped steel sheet piles (NAVFAC, 2020). Similarly, source
levels for impact pile driving of an 18-inch flat-webbed sheet pile
were unavailable, so proxy values for installation of a 24-inch Z-
shaped sheet pile are used. In the notice of the proposed IHA, the
proxy source levels were incorrectly specified. As a result of NMFS'
review of public comment, the approach to estimating the source levels
for this pile type was modified by taking the mean of the maximum
values for each type of sound level in Table 1.6-5 of CALTRANS (2015),
resulting in the decreased source levels shown in Table 6.
The source levels in Table 6 are assumed for pile driving and
drilling underwater noise produced by construction activities.
[[Page 30425]]
Table 6--Summary of In-Water Pile Driving Source Levels
[at 10 m from source]
----------------------------------------------------------------------------------------------------------------
Installation/ SPLrms, dB re
Pile type extraction Pile diameter SPLpk, dB re 1 [micro]Pa SEL, dB re 1
method (inch) 1 [micro]Pa [micro]Pa\2\-s
----------------------------------------------------------------------------------------------------------------
Z-shaped steel sheet \1\ \3\.. Vibratory \2\... 28 NA 167 167
Impact \3\...... 28 211 196 181
Flat-webbed steel sheet \1\ Vibratory....... 18 NA 163 163
\4\.
Impact.......... 18 201 183 172
Steel pipe \2\................ Vibratory....... 30 NA 167 167
Blast holes \5\............... Drilling........ 4.5 NA 166.2 166.2
----------------------------------------------------------------------------------------------------------------
Key: dB = decibels; NA = Not applicable; dB re 1 [mu]Pa = dB referenced to a pressure of 1 micropascal, measures
underwater SPL. dB re 1 [mu]Pa2-s = dB referenced to a pressure of 1 micropascal squared per second, measures
underwater SEL.
\1\ = A proxy value for 28-inch sheet piles could not be found for impact and vibratory driving so the proxy for
a 30-inch steel pipe pile has been used (NAVFAC SW 2020). A proxy value for 18-inch flat-webbed sheet piles
could not be found for impact and vibratory driving so the proxy for a 24-inch Z-shaped sheet pile has been
used (CALTRANS 2015).
Sources: DoN 2015 \2\; NAVFAC SW 2020 \3\ CALTRANS 2015 \4\; Denes et al., 2016.\5\
The proxy source level for drilling of blast-charge holes is
derived from Denes et al. (2016), which reports sound pressure levels
measured during rock socket drilling at Kodiak Ferry Terminal in
Alaska. The size of the blast-charge holes considered here (4.5-inch)
is much smaller than the size of the drilled holes (24-inch) in Denes
et al. (2016), making the use of 166.2 dB re 1[micro]Pa conservative.
There are no data on sound source levels from explosives used under
circumstances identical to the blasting activity described here (e.g.,
charge composition and weight, bathymetry, substrate composition, and
the dimensions of holes for stemmed charge placement). Therefore, the
Navy made approximations by reference to mathematical models that have
been empirically validated, under roughly comparable circumstances, to
estimate source levels both in terms of absolute peak sound pressure
level (SPL in units of dB re 1[micro]Pa) and sound exposure level (SEL
in units of dB re 1[micro]Pa\2\-s) (Table 7). The peak source level
calculation of a confined blast follows Cole's (1948) equation and a
regression curve from the Miami Harbor Deepening Project (Hempen et al.
2007), using a distance of 2.4 m and a weight of 120 pounds (lbs) for a
single charge. Based on this approach, the peak source level for the
project is estimated to be 257 dB re 1 [micro]Pa for a 120 lb charge.
Following Urick (1983), the Navy estimated the SEL for 30, 120 lb
charges at 1 m by first calculating the instantaneous pressure
following the onset of a shock wave, as a relationship between peak
pressure and time. Blasting operations will involve detonating 120 lb
up to 30 times in rapid succession, with a split second delay between
each detonation. Without specific information regarding the layout of
the charges, the modeling assumes a grid of 2.4 m by 2.4 m charges for
the majority of the super flood basin, and 1.5 m by 1.8 m for the rows
closest to Berth 11. Due to time and spatial separation of each single
charge by a distance of 2.4 m, the accumulation of acoustic energy is
added sequentially, assuming the transmission loss follows cylindrical
spreading within the matrix of charges. Using this approach for
multiple confined charges, the modeled source SEL for 30, 120 lb
charges at 1 m is estimated to be 227 dB re 1[micro]Pa\2\-s. Please see
the Navy's IHA application for more details regarding these
calculations.
Table 7--Blasting Source Levels
------------------------------------------------------------------------
SPLpk, (dB SEL (dB re 1
Explosive charge re 1 [micro]Pa\2\-
[micro]Pa) s)
------------------------------------------------------------------------
30 x 120 lb charge.......................... 257 227
------------------------------------------------------------------------
These source levels for pile driving, drilling, and blasting are
used to estimate the Level B harassment zones and calculate the Level A
harassment zones.
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:
(1) TL = B * log10(R1/R2)
Where,
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.
The degree to which underwater sound propagates away from a sound
source is dependent on a variety of factors, most notably the water
bathymetry and presence or absence of reflective or absorptive
conditions including in-water structures and sediments. Spherical
spreading occurs in a perfectly unobstructed (free-field) environment
not limited by depth or water surface, resulting in a 6 dB reduction in
sound level for each doubling of distance from the source
(20*log[range]). Cylindrical spreading occurs in an environment in
which sound propagation is bounded by the water surface and sea bottom,
resulting in a reduction of 3 dB in sound level for each doubling of
distance from the source (10*log[range]). A practical spreading value
of 15 is often used under conditions, such as at the Shipyard dock,
where water increases with depth as the receiver moves away from the
shoreline, resulting in an expected propagation environment that would
lie between spherical and cylindrical spreading loss conditions. The
Level B harassment distances for construction activities are calculated
using practical spreading (impact and vibratory pile driving, drilling)
and spherical spreading with absorption (blasting), which includes an
additional term in the equation that accounts for frequency-specific
transmission loss to the environment due to absorption, using the
source levels provided in Tables 6 and 7, respectively.
Ensonified areas (A) are calculated using the following equation.
(2) A = [pi]R\2\
Where,
R is the harassment distance.
However, the maximum distance from the source is capped due to
landmass interception in the surrounding area. For this reason, the
maximum area that could be ensonified by noise from pile driving and
drilling is an estimated 0.418 km\2\. Therefore, all harassment zones
that are larger than 0.418 km\2\ are corrected to this maximum value.
The
[[Page 30426]]
maximum ensonified area for blasting is smaller (0.335 km\2\) because,
prior to the removal of bedrock, a portion of the west closure wall
will be installed, providing an additional boundary between noise
produced within the super flood basin and the surrounding environment.
Level A Harassment Zones
When the original NMFS Technical Guidance (2016) was published, in
recognition of the fact that the ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, NMFS developed a User Spreadsheet that includes
tools to help predict a simple isopleth that can be used in conjunction
with marine mammal density or occurrence to help predict takes. NMFS
notes that because of some of the assumptions included in the methods
used for these tools, NMFS anticipates that isopleths produced are
typically going to be overestimates of some degree, which may result in
some degree of overestimate of Level A harassment take. However, these
tools offer the best way to predict appropriate isopleths when more
sophisticated 3D modeling methods are not available, and NMFS continues
to develop ways to quantitatively refine these tools, and will
qualitatively address the output where appropriate. For stationary
sources such as in-water vibratory and impact pile driving, NMFS User
Spreadsheet predicts the closest distance at which, if a marine mammal
remained at that distance the entire duration of the activity, it would
not incur PTS. Inputs used in the User Spreadsheet (i.e., pile driving
duration or number of strikes per pile, and the number of piles
installed or removed per day) used to calculate distances to the Level
A harassment isopleths for pile driving and drilling are shown in Table
8.
For blasting, the calculated distances to Level A harassment
thresholds are based on a single blast event per day. The Navy plans to
conduct 150 blast events over 130 days, so on the majority of
construction days (110) only one blast event will occur. NMFS
recognizes that if two blasts do occur on a single day, the cumulative
SEL for the 24-hour timeframe over which blasting occurs would be
higher than that analyzed here. However, the distances to the Level A
harassment thresholds in Table 9 do not reflect the attenuating
influence of the double bubble curtain that will be in place across any
openings between the super flood basin and the surrounding environment
during blasting events. If multiple blast events occur within a 24-hour
period, they will be separated by 4 to 5 hours. It is likely that if
marine mammals are present in the vicinity of the construction area
(outside of the shutdown zone) during the first blast event they will
avoid the area for at least the remainder of day.
Blasting will occur at multiple locations within the super flood
basin. The minimum and maximum distances from the blasting locations to
the center of the entrance to the super flood basin are 37.5 and 160 m,
respectively. Acoustic modeling is based on the location closest to the
entrance to the basin; the resulting distances to Level B harassment
and Level A harassment isopleths are, therefore, a conservative
estimate of the maximum extent of potential acoustic impact outside of
the basin. The distance to the Level A harassment isopleth for blasting
for harbor porpoises (1,007 m) is larger than that for phocids (110 m),
but the density of harbor porpoises near the construction area is very
low (see Marine Mammal Occurrence section). Harbor seals and gray seals
are more common, but the distance to the Level A harassment isopleth
for phocids is fully encompassed by the shutdown zone.
The Level A harassment zones are calculated using the same Equation
(2). For all pile driving/drilling activities, ensonified areas are
based on distances to the cumulative SEL Level A harassment thresholds
using the NMFS acoustic guidance (NMFS 2018) because they were larger
than the values calculated against the SPL<INF>peak</INF> criteria.
Following the approach used for estimating Level B harassment zones, if
the calculated value is larger than the maximum potential ensonified
zone, Level A harassment zones are corrected to 0.418 km\2\ for pile
driving activity and 0.335 km\2\ for blasting activity.
The calculated distances to Level A harassment and non-auditory
injury (to the gastrointestinal tract) isopleths, estimated distances
to Level B harassment isopleths, and associated ensonified areas for
the marine mammal species likely to be affected by the construction
activities are provided in Tables 8 and 9.
Table 8--Distances and Areas of Harassment Zones for Pile Driving and Drilling
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment Level B harassment
-------------------------------------------------------------------
Pile size, type, Number of strikes/ Number of HF cetacean Phocid
Activity and rate pile or duration days ---------------------------------------------- Area
Area Area Dist. (m) (km\2\)
Dist. (m) (km\2\) Dist. (m) (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impulsive
--------------------------------------------------------------------------------------------------------------------------------------------------------
Construct west closure wall..... 18-inch flat-webbed 300............... 13 516 0.258 232 0.068 341 0.126
sheet pile (12
pile/day).
Entrance structure closure walls 28-inch Z-shaped 300............... 4 2,056 0.418 923 0.395 2,512 0.418
sheet pile (12
pile/day).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Non-impulsive
--------------------------------------------------------------------------------------------------------------------------------------------------------
Construct west closure wall..... 18-inch flat-webbed 5 min/pile 60 min/ 13 13.7 0.000556 5.6 0.00098 7,356 0.418
sheet pile (12 day.
pile/day).
Install west closure wall 30-inch steel pipe 5 min/pile 15 min/ 5 10.1 0.000319 4.1 0.000053 13,594 0.418
template. pile (3 pile/day). day.
Remove west closure wall 30-inch steel pipe 5 min/pile 15 min/ 5 10.1 0.000319 4.1 0.000053 13,594 0.418
template. pile (3 pile/day). day.
Remove temporary dolphins....... 30-inch steel pipe 5 min/pile 40 min/ 2 19.4 0.01068 8.0 0.001996 13,594 0.418
pile (8 pile/day). day.
Entrance structure closure walls 28-inch Z-shaped 5 min/pile 60 min/ 4 25.4 0.00174675 10.4 0.000338 13,594 0.418
sheet pile (12 day.
pile/day).
[[Page 30427]]
Bedrock drilling for blast 4.5-inch (1,580 12 hr/day......... 130 7 0.000153 4.3 0.000058 12,023 0.418
charges. holes).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* 0.418 km\2\ is the maximum ensonified area in the project area for pile driving and drilling due to landmass interception of sound propagation.
Table 9--Distances and Areas of Harassment Zones for Blasting
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A (PTS onset) harassment \1\ Level B (behavioral) harassment Non-auditory injury
----------------------------------------------------------------------- (gastrointestinal tract)
---------------------------------
Phocid/harbor
Harbor porpoise Phocids distance Harbor porpoise Phocids porpoise Phocid/harbor
Blasting events and charge Blasting days distance to 155 to 185 dB SELcum distance to 135 distance to 165 distance to 237 porpoise
dB SELcum threshold/area dB SELcum dB SELcum dB peak distance to 243
threshold/area of ZOI threshold/area threshold/area pressure dB peak
of ZOI of ZOI of ZOI threshold/area pressure
of ZOI (onset threshold/area
of effect) of ZOI (injury)
--------------------------------------------------------------------------------------------------------------------------------------------------------
5-30 blasts per event, 120-lb 130 (1-2 events/ 1,007 m/0.335 110 m/0.01978 2,131 m/0.335 577 m/0.27636 9 m/0.000254 5 m/0.00008
charge per blast event, 150 day). km\2\. km\2\. km\2\. km\2\. km\2\. km\2\
blast events.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* 0.335 km\2\ is the maximum ensonified area for blasting in the project area due to landmass interception of sound propagation.
\1\ Distance to 202 dB SPLpeak threshold for harbor porpoises is 19 m, and to 218 dB SPLpeak threshold for phocids is 3 m.
Marine Mammal Occurrence
Marine mammal density estimates for the harbor porpoise, harbor
seal, and gray seal are based on marine mammal monitoring observations
during 2017 and 2018 (CIANBRO 2018a, b). Density values were calculated
from visual sightings of all marine mammals divided by the monitoring
days (total of 154 days) and the total ensonified area in which the
sightings occurred in the 2017 and 2018 activities (0.8401 km\2\).
Details used for calculations are provided in Table 10 and described
below.
Table 10--Marine Mammal Sightings and Resulting Density in the Vicinity of Portsmouth Naval Shipyard
----------------------------------------------------------------------------------------------------------------
2017 sighting 2018 sighting Density (animal/
Species (96 days) (58 days) Total sighting day/km\2\)
----------------------------------------------------------------------------------------------------------------
Harbor porpoise............................... 3 2 5 0.04
Harbor seal................................... 199 122 321 2.48
Gray seal..................................... 24 2 26 0.20
----------------------------------------------------------------------------------------------------------------
Hooded and harp seals are much rarer than harbor and gray seals in
the Piscataqua River, and no density information for these two species
is available. To date, marine mammal monitoring for the Berth 11
Waterfront Improvements Construction project has not recorded a
sighting of a hooded or harp seal in the project area (Cianbro 2018ab;
NAVFAC Mid-Atlantic 2018, 2019b; Navy 2019; Stantec 2020); however, two
harp seals were observed outside of the timeframe of dedicated marine
mammal monitoring of Berth 11 pile-driving activities, one on May 12,
2020 and one on May 14, 2020 (Stantec 2020). The Navy requested
authorization of take for these two species, given the potential for
occurrence, and NMFS is acting on that request.
Take Calculation and Estimation
The approach by which the information provided above is brought
together to produce a quantitative take estimate is described here.
For marine mammals with calculated density information (i.e.,
harbor porpoise, harbor seal, and gray seal), in general, estimated
Level B harassment and Level A harassment take numbers are calculated
using the following equation:
Estimated take = animal density x ensonified area x operating days (3)
However, in consideration of the prevalence of seals in the project
area and in accordance with the approach utilized in IHAs previously
issued to the Navy for expansion and modification of DD1, NMFS has
determined that it is appropriate to increase the number of harbor seal
and gray seal Level B behavioral harassment takes. Harbor seal Level B
behavioral harassment takes have been adjusted upwards by multiplying
the average number of harbor seals sighted per day from May through
December 2020 (721 sightings divided by 150 days of monitoring, or 5
harbor seals/day) by the number of actual construction days (159),
resulting in 795 Level B behavioral harassment takes. Gray seal Level B
harassment takes have been increased utilizing the same approach (47
sightings divided by 150 days of monitoring, or 0.31 gray seals/day),
resulting in 50 Level B behavioral harassment takes.
NMFS authorized one Level B harassment take per month for both
hooded seals and harp seals for the Berth 11 Waterfront Improvements
construction project in both 2018 and 2019. Following the same
approach, the Navy has requested, and NMFS has authorized, one Level B
harassment take each of hooded seals and harp seals per
[[Page 30428]]
month of construction from January through May, when these species may
occur in the vicinity of DD1 (total of 5 Level B harassment takes for
each species).
The total number of takes authorized is presented in Table 11. Non-
auditory take estimates were zero for all species and are, therefore,
not included in Table 11.
BILLING CODE 3510-22-P
[[Page 30429]]
[GRAPHIC] [TIFF OMITTED] TN08JN21.017
[[Page 30430]]
BILLING CODE 3510-22-C
Mitigation Requirements
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 such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting such 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
carefully 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, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In addition to the measures described later in this section, the
Navy will employ the following standard mitigation measures:
<bullet> The Navy must employ PSOs, establish monitoring locations,
and monitor the project area to the maximum extent possible based on
the required number of PSOs, required monitoring locations, and
environmental conditions;
<bullet> Monitoring must take place from 30 minutes prior to
initiation of construction activities through 30 minutes post-
completion of pile-driving and drilling, and 60 minutes post-completion
of blasting events;
<bullet> The Navy must conduct a briefing between construction
supervisors and crews and the marine mammal monitoring team prior to
the start of construction, and when new personnel join the work, to
explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures;
<bullet> For in-water and over-water heavy machinery work, if a
marine mammal comes within 10 m, operations shall cease and vessels
shall reduce speed to the minimum level required to maintain steerage
and safe working conditions;
<bullet> With the exception of pre-dawn drilling, work must only
occur during daylight hours, when visual monitoring of marine mammals
can be conducted;
<bullet> For those marine mammals for which take has not been
requested, pile driving and removal, drilling, and blasting will shut
down immediately when the animals are sighted approaching the Level B
harassment zone;
<bullet> If take reaches the authorized limit for an authorized
species, activity for which take is authorized will be stopped as these
species approach the Level B harassment zone to avoid additional take;
<bullet> Blasting will not begin until at least one sheet pile face
of the west closure wall has been installed;
<bullet> Blasting must only occur in good visibility conditions
between 30 minutes after sunrise and one hour before sunset;
<bullet> Stemming procedures must be used for blasting events; and
<bullet> A double bubble curtain will be installed across any
openings at the entrance of DD1 to mitigate underwater noise impacts
outside of the super flood basin during pre-dawn drilling of blast-
charge holes and blasting events.
The following measures will apply to the Navy's mitigation
requirements:
Monitoring Harassment Zones--Before the commencement of in-water
construction activities (i.e., impact pile driving, vibratory pile
driving and pile removal, drilling, and blasting), Level B harassment
and Level A harassment zones must be established for purposes of
monitoring. Monitoring zones enable observers to be aware of and
communicate the presence of marine mammals in the project area outside
of the shutdown zone (see below) and thus prepare for a potential cease
of activity should the animal enter the shutdown zone. All Level B
harassment monitoring zones for the construction activities are
equivalent to the maximum ensonified zone, adjusted for landmass
interception, or 0.418 km\2\. Similarly, harassment monitoring zones
must be established for the PTS isopleths associated with each
functional hearing group.
Shutdown Zones--The Navy will implement shutdown zones for all pile
driving and removal, drilling, and blasting activities. The purpose of
a shutdown is to prevent some undesirable outcome, such as auditory
injury or severe behavioral disturbance of sensitive species, by
halting the activity. If a marine mammal is observed entering or within
the respective shutdown zone (Table 12) after a construction activity
has begun, the PSO will request a temporary cessation of the
construction activity. On days when multiple activities are occurring
concurrently, the largest shutdown zone between/among the activities
will be implemented. The shutdown zone for blasting will be the entire
region of influence (ROI), equivalent to the maximum ensonified zone
adjusted for landmass interception (0.335 km\2\). If shutdown zones are
obscured by fog or poor lighting conditions, pile-driving and blasting
will not be initiated until the entire shutdown zones are visible.
Although drilling activities may occur during pre-dawn hours in
order to maintain the project schedule, the shutdown distance for
drilling is small (10 m) and will likely be entirely visible for
monitoring despite visibility limitations during this timeframe. As
mentioned previously, drilling will not occur between sunset and pre-
dawn hours.
Shutdown zones typically vary based on the activity type and marine
mammal hearing group. A summary of the shutdown zones is provided in
Table 12.
[[Page 30431]]
Table 12--Shutdown Zones Distances for Construction Activities and
Marine Mammal Hearing Groups
------------------------------------------------------------------------
Shutdown distance (m)
Pile type, size & driving ----------------------------------------
method HF cetacean Phocid
------------------------------------------------------------------------
Vibratory drive 30-inch steel 70................. 30
pipe piles.
Vibratory extraction 30-inch 70................. 30.
steel pipe piles.
Impact drive 28-inch steel 110................ 50.
sheet piles.
Vibratory drive 28-inch steel 25................. 10.
sheet piles.
Impact drive 18-inch sheet 110................ 50.
piles.
Vibratory drive 18-inch sheet 15................. 10.
piles.
Drilling 4.5-inch blast charge 10................. 10.
holes.
Blasting 120 lb charge......... Entire ROI \1\..... Entire ROI.
------------------------------------------------------------------------
\1\ Region of influence (ROI) for blasting is the maximum ensonified
area (0.335 km\2\).
Pre-start Clearance Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving/
removal or drilling of 30 minutes or longer occurs, PSOs will observe
the shutdown zones for a period of 30 minutes. The shutdown zone will
be considered cleared when a marine mammal has not been observed within
the zone for that 30-minute period. If a marine mammal is observed
within the shutdown zone, no construction activity, including soft-
start (see below), can proceed until the animal has voluntarily left
the zone 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 may begin. If the entire Level B
harassment zone is not visible at the start of construction, pile
driving activities can begin. If work ceases for more than 30 minutes,
the pre-activity monitoring of the shutdown zones will commence.
Soft Start--The use of a soft start procedure is believed to
provide additional protection to marine mammals by warning marine
mammals or providing them with a chance to leave the area prior to the
hammer operating at full capacity, and typically involves a requirement
to initiate sound from the hammer at reduced energy followed by a
waiting period. The Navy will provide an initial set of strikes from
the impact hammer at reduced energy, followed by a 30 second waiting
period, and then two subsequent sets. NMFS notes that it is difficult
to specify the reduction in energy for any given hammer because of
variation across drivers and, for impact hammers, the actual number of
strikes at reduced energy will vary because operating the hammer at
less than full power results in ``bouncing'' of the hammer as it
strikes the pile, resulting in multiple ``strikes''. Soft start will be
implemented at the start of each day's impact pile driving and at any
time following cessation of impact pile driving for a period of 30
minutes or longer.
Based on our evaluation of the required measures, NMFS has
determined that the prescribed mitigation measures provide the means
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.
Monitoring and Reporting Requirements
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 in the
action area. 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.
Monitoring Requirements
The Navy shall employ trained PSOs to conduct marine mammal
monitoring for its PNSY modification and expansion project. The
purposes of marine mammal monitoring are to implement mitigation
measures and learn more about impacts to marine mammals from the Navy's
construction activities.
Protected Species Observer Qualifications
NMFS-approved PSOs shall meet the following requirements:
1. Independent observers (i.e., not construction personnel) are
required;
2. At least one observer must have prior experience working as an
observer;
3. Other observers may substitute education (undergraduate degree
in biological science or related field) or training for experience;
4. Where a team of three or more observers are required, one
observer should be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer; and
5. NMFS will require submission and approval of observer curricula
vitae (CVs).
[[Page 30432]]
Marine Mammal Monitoring Protocols
The Navy will monitor all Level B harassment zones and Level A
harassment zones before, during, and after construction activities. The
Marine Mammal Monitoring Plan must include the following procedures:
<bullet> At least two (2) PSOs shall be posted to monitor marine
mammals during in-water pile driving and removal, drilling, and
blasting. Additional PSOs will be required in conditions of low
visibility (i.e., rain or light fog), for activities producing the
largest ensonified zones, and/or if marine mammal occurrence is higher
than expected in the project area;
<bullet> PSOs must be stationed at the best possible vantage
point(s) in order to properly see the entire shutdown zone(s) and zones
associated with behavioral impact thresholds, which may include the
following locations: Berth 2, Berth 12, Isle of Shoals Steamship
Company, Prescott Park, Four Tree Island, Peirce Island, and/or a boat
or barge within the project limits;
<bullet> PSOs must record all observations of marine mammals,
regardless of distance from the construction activity;
<bullet> During all observation periods, PSOs will use high-
magnification (25X), as well as standard handheld (7X) binoculars, and
the naked eye to search continuously for marine mammals;
<bullet> Monitoring distances will be measured with range finders.
Distances to animals will be based on the best estimate of the PSO,
relative to known distances to objects in the vicinity of the PSO;
<bullet> Pile driving and removal, drilling, and blasting will only
take place when the shutdown zones are visible and can be adequately
monitored. If conditions (e.g., fog) prevent the visual detection of
marine mammals, activities with the potential to result in Level A
harassment shall not be initiated. If such conditions arise after the
activity has begun, blasting and impact pile driving or removal will be
halted but drilling and vibratory pile driving or removal will be
allowed to continue;
Information Collection:
PSOs shall collect the following information during marine mammal
monitoring:
[cir] PSO locations during monitoring;
[cir] Date and time that monitored activity begins and ends for
each day conducted (monitoring period);
[cir] Construction activities occurring during each daily
observation period, including how many and what type of piles driven,
number of blast holes drilled, and number or blast events;
[cir] 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
estimated observable distance;
[cir] For each marine mammal sighting:
<bullet> Name of PSO who sighted the animal(s) and PSO location and
activity at time of sighting;
<bullet> Time of sighting;
<bullet> Species, numbers, and, if possible, sex and age class of
marine mammals;
<bullet> Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
construction activity;
<bullet> Location, distance, and bearing from pile driving,
drilling, and blasting activities to marine mammals and distance from
the marine mammals to the observation point;
<bullet> Animal's closet point of approach and estimated amount of
time that the animals remained in the Level B harassment and Level A
harassment zones; and
<bullet> Detailed information about implementation of any
mitigation (e.g., shutdowns or delays), a description of specific
actions that ensued, and resulting changes in behavior of the
animal(s), if any.
<bullet> Percentage of time that activities (i.e., drilling) occur
at night.
Hydroacoustic Monitoring
The Navy must conduct hydroacoustic monitoring of in-water
construction activities, including the installation of (10) 28-inch Z-
shaped sheet piles and (10) 18-inch flat-webbed sheet piles for both
impact and vibratory pile driving, (4) 30-inch steel piles for
vibratory pile driving, (10) 120 lbs blasting events, and (10) 4.5-inch
blast-charge hole drilling events. Near-field monitoring will occur at
10 m from the pile driving hammers and drilling location. During
blasting, near-field data will be collected using a pressure transducer
to estimate sounds levels based on received impulse. The far-field
hydrophone will be placed as far from the acoustic source as is
practicable, although the distance will limited by DD1's proximity to a
navigable channel outside of the entrance to the super flood basin.
Monitoring will only be conducted when concurrent activities are not
occurring, limiting interference in the recordings from other sources
of noise in the environment.
Reporting Requirements
The Navy is required to submit a draft monitoring report (including
all PSO data sheets and/or raw sighting data) within 90 days after
completion of the construction work or the expiration of the IHA,
whichever comes earlier. This report must detail the monitoring
protocol, summarize the data recorded during monitoring, and estimate
the number of marine mammals that may have been harassed. The draft
hydroacoustic monitoring report must be submitted within the same
timeframe and must contain the informational elements described in the
hydroacoustic monitoring plan for all acoustically monitored events,
including: A description of the hydrophones used, hydrophone locations
(both near- and far-field) and water depths, recording device(s),
distance from the acoustic source, and sediment type at the recording
location; type and size of pile being driven, method of pile-driving
during recording (hammer model and energy), and total driving/removal
or drilling duration. For impact pile driving, the Navy must also
report: Number of strikes and strike rate, depth of substrate
penetrated, pulse duration, and mean, median, and maximum sound levels
(db re 1 [micro] 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>)). For
vibratory pile driving or removal and drilling, the Navy must also
report: Median, minimum and maximum sound levels (db re 1 [micro] Pa)
(SPLrms, SELcum), and the timeframe over which the sound is averaged.
For blast events, the Navy must also report: Number of blast events per
day, time between blast events if two are conducted within a 24-hour
period, total number of charges/delays, maximum net explosive weight
(NEW) of a single charge and the total NEW of the event, timeframe
between delays and total timeframe of event, impulse in Pa-sec,
SPL<INF>peak</INF> for each event and SEL<INF>cum</INF> values for the
entire 24 hours over which blasting occurs. For all activities,
reported SPL<INF>rms</INF> values must be based on a time window that
consists of 90 percent of the acoustic energy. Power spectral density
plots and one-third octave band spectra must be provided for all
acoustically monitored construction activities. If, for any reason, the
total number of events included in the hydroacoustic monitoring plan
are not monitored within the overall construction timeframe, the Navy
must report the actual number of events monitored. NMFS will have an
opportunity to provide comments on the report and, if NMFS has
comments, the Navy will address the comments and submit a final report
to NMFS within 30 days.
[[Page 30433]]
The Navy is required to notify NMFS' Office of Protected Resources
(OPR) and NMFS' Greater Atlantic Regional Stranding Coordinator or
local stranding network at least 24 hours prior to commencing blasting
events as well as within 24 hours after blasting events cease. If
blasting events occur on consecutive days, the Navy must communicate
how long the blasting is scheduled to last as well as when it is
completed. In addition, in the event that personnel involved in the
construction activities discover an injured or dead marine mammal, the
Navy must immediately report the incident to NMFS OPR and the Stranding
Coordinator or local stranding network and follow any instructions
provided by the Stranding Coordinator or stranding network. If the
death or injury was clearly caused by the specific activity, the Navy
must immediately cease the specified activities until NMFS OPR is able
to review the circumstances of the incident and determine what, if any,
additional measures are appropriate to ensure compliance with the terms
of the IHA. The Navy must not resume their activities until notified by
NMFS OPR. The Navy shall provide NMFS OPR and the Stranding Coordinator
or local stranding network with the species or description of the
animal(s), the condition of the animal(s) (including carcass condition,
if the animal is dead), location, time of first discovery, observed
behaviors (if alive), and photo or video (if available).
In the event that the Navy finds an injured or dead marine mammal
that is not in the construction area, the Navy would report the same
information as listed above to the Stranding Coordinator or local
stranding network and NMFS OPR as soon as is operationally feasible.
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 responses (e.g., intensity, duration), the context
of any responses (e.g., critical reproductive time or location,
migration), as well as effects on habitat, and the likely effectiveness
of the mitigation. NMFS also assesses 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 environmental 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).
Pile driving and removal, drilling, and blasting activities
associated with the project, as described previously, have the
potential to disturb or temporarily displace marine mammals. The
specified activities may result in take, in the form of Level A
harassment (potential injury; from impact pile driving or blasting) or
Level B harassment (potential behavioral disturbance or TTS) from
underwater sounds generated from pile driving (impact and vibratory),
drilling and blasting. Potential takes could occur if individual marine
mammals are present in the ensonified zone when pile driving, drilling,
or blasting activities are occurring.
To avoid repetition, this introductory discussion of NMFS' analysis
applies to all of the species listed in Table 2, given that the
anticipated effects of the Navy's PNSY modification and expansion
construction project activities on marine mammals are expected to be
relatively similar in nature. There is no information about the nature
or severity of the impacts, or the size, status, or structure of any
species or stock that would lead to a different analysis by species for
this activity, or else species-specific factors would be identified and
analyzed.
Although some individual harbor porpoises and harbor and gray seals
are estimated to experience Level A harassment in the form of PTS if
they remain within the impact pile driving Level A harassment zone for
an entire day, or are present within the Level A harassment zone during
a blasting event, the degree of injury is expected to be mild and is
not likely to affect the reproduction or survival of the individual
animals. It is expected that, if hearing impairments occurs as a result
of impact pile driving or blasting, the affected animal would lose a
few dB in its hearing sensitivity, which in most cases is not likely to
affect its survival and recruitment. Hearing impairment that might
occur for these individual animals would be limited to the dominant
frequency of the noise sources, (i.e., in the low-frequency region
below 2 kHz). Nevertheless, as for all marine mammal species, it is
anticipated that, in general, these pinnipeds will avoid areas where
sound levels could cause hearing impairment. Therefore, it is not
likely that an animal would stay in an area with intense noise that
could cause severe levels of hearing damage.
Under the majority of the circumstances, anticipated takes are
expected to be limited to short-term Level B behavioral harassment or
TTS. Marine mammals present in the vicinity of the action area and
taken by Level B harassment would most likely show overt brief
disturbance (startle reaction) from blasting events and avoidance of
the area impacted by elevated noise levels during pile driving (and
removal) and drilling. Given the limited estimated number of predicted
incidents of Level B harassment and Level A harassment and the limited,
short-term nature of the responses by the individuals, the impacts of
the estimated take cannot be reasonably expected to, and are not
reasonably likely to, rise to the level that they would adversely
affect the species considered here at the population level, through
effects on annual rates of recruitment or survival. There are no known
important habitats, such as rookeries or haulouts, in the vicinity of
the Navy's PNSY DD1 modification and expansion construction project.
The project also is not expected to have significant adverse effects on
affected marine mammals' habitat, including prey, as analyzed in detail
in the Potential Effects of Specified Activities on Marine Mammals and
their Habitat section in the Federal Register notice for the proposed
IHA (86 FR 18244; April 8, 2021).
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 the species or stock through
effects on annual rates of recruitment or survival:
<bullet> No mortality is anticipated or authorized;
<bullet> Some individual marine mammals might experience a mild
level of PTS, but the degree of PTS is not expected to affect their
survival;
<bullet> Most adverse effects to marine mammals are likely to be
temporary behavioral harassment or TTS; and
[[Page 30434]]
<bullet> No biologically important area is present in or near the
construction area.
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
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 section 101(a)(5)(A) and (D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, 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 less 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.
NMFS authorizes incidental take of 5 marine mammal stocks. The
total amount of take authorized is three percent or less for all five
of these stocks (Table 11).
Based on the analysis contained herein of the activity (including
the prescribed 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 would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act (ESA)
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 (IHA 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 NMFS has 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
As a result of these determinations, NMFS has issued an IHA to the
Navy for the taking of marine mammals incidental to modification and
expansion of the Portsmouth Naval Shipyard Dry Dock 1 in Kittery,
Maine, effective for one year from the date of issuance, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. A copy of the final IHA can be found at <a href="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</a>.
Dated: June 3, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2021-11983 Filed 6-7-21; 8:45 am]
BILLING CODE 3510-22-P
</pre></body>
</html>Indexed from Federal Register on June 8, 2021.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.