[Federal Register Volume 85, Number 55 (Friday, March 20, 2020)]
[Notices]
[Pages 16061-16077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-05802]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XR035]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Parallel Thimble Shoal Tunnel
Project in Virginia Beach, Virginia
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA), as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the Chesapeake Tunnel Joint Venture (CTJV) to incidentally take, by
Level A harassment and Level B harassment, five species of marine
mammals during the Parallel Thimble Shoal Tunnel Project (PTST) in
Virginia Beach, Virginia.
DATES: This Authorization is effective from March 10, 2020 through
March 09, 2021.
FOR FURTHER INFORMATION CONTACT: Robert Pauline, Office of Protected
Resources, NMFS, (301) 427-8401. Electronic copies of the application
and supporting documents, as well as a list of the references cited in
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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
[[Page 16062]]
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are 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 in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of such takings are set forth.
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
Summary of Request
On May 24, 2019, NMFS received a request from the CTJV for an IHA
to take marine mammals incidental to pile driving and removal at the
Chesapeake Bay Bridge and Tunnel (CBBT) near Virginia Beach, Virginia.
The application was deemed adequate and complete on October 11, 2019.
The CTJV's request is for take of small numbers of harbor seal (Phoca
vitulina), gray seal (Halichoerus grypus), bottlenose dolphin (Tursiops
truncatus), harbor porpoise (Phocoena phocoena) and humpback whale
(Megaptera novaeangliae) by Level A and Level B harassment. Neither the
CTJV nor NMFS expects serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
Description of Activity
Overview
The CTJV requested authorization for take of marine mammals
incidental to in-water construction activities associated with the PTST
project. The project consists of the construction of a two-lane
parallel tunnel to the west of the existing Thimble Shoal Tunnel,
connecting Portal Island Nos. 1 and 2 of the CBBT facility which
extends across the mouth of the Chesapeake Bay near Virginia Beach,
Virginia. Upon completion, the new tunnel will carry two lanes of
southbound traffic and the existing tunnel will remain in operation and
carry two lanes of northbound traffic. The PTST project will address
existing constraints to regional mobility based on current traffic
volume along the facility. Construction will include the installation
and removal of 812 piles over 198 days as shown below in Table 1. Due
to minor construction design changes, the Federal Register notice
announcing the proposed IHA (84 FR 64847; November 25, 2019), had
originally estimated that there were would be 878 piles installed and
removed over 188 days.
In-water activities associated with the project include impact
driving, vibratory driving and drilling with down-the-hole (DTH)
hammers. Some piles will be removed via vibratory hammer. Work will
occur during standard daylight hours of approximately 8-12 hours per
day depending on the season. In-water work will occur every month with
the exception of February 2021. In-water construction associated with
this IHA will begin in winter of 2020.
The PTST project has been divided into four phases over 5 years.
Phase I commenced in June 2017 and consisted of upland pre-tunnel
excavation activities, while Phase IV is scheduled to be completed in
May of 2022. In-water activities are limited to Phase II and,
potentially, Phase IV (if substructure repair work is required at the
fishing pier and/or bridge trestles and abutments). Take of marine
mammals authorized under this IHA will occur for one year from the date
of issuance.
A detailed description of the planned activities is provided in the
Federal Register notice announcing the proposed IHA (84 FR 64847;
November 25, 2019). Since that time the CTJV has made minor revisions
to the project's construction schedule. The project is now planned to
occur over 11 months with no in-water activity in February 2021. The
project schedule contained in the proposed IHA was to occur over 10
months with no in-water work during September and October of 2020. The
in-water activities described in the proposed IHA Federal Register
notice generally remain the same. Any changes from the proposed IHA
Federal Register notice are identified in this notice. Therefore, a
detailed description is not provided here. Please refer to the proposed
IHA Federal Register notice for a detailed description of the activity.
Table 1--Pile Driving Activities Associated With the PTST Project
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Number of days
Bubble Number of Number of per activity Anticipated
Pile location Pile function Pile type Installation/ curtain piles days per (per hammer installation
removal method (yes/no) below MHW activity type) full date
(total) production
--------------------------------------------------------------------------------------------------------------------------------------------------------
Portal Island No. 1.......... Mooring dolphins 12-inch Timber Vibratory No 120 18 18 Days (7 Piles/ 1 May 2020
piles. (Install). No ......... ......... Day). through 20 June
Impact (if 14 Days (9 Piles/ 2020.
needed). Day)..
Portal Island No. 1.......... Temporary Dock.. 42-inch Diameter DTH (install)... No 58 20 20 Days (3 Piles/ 7 Feb 2019
Steel Pipe Vibratory No ......... ......... day). through 7 June
Casing *. (removal). 10 Days (6 Piles/ 2020.
day)..
36-inch Diameter Impact.......... Yes ......... 20 20 Days (3 Piles/
Steel Pipe Pile. day).
Portal Island No. 1.......... Omega Trestle... 36-inch Diameter DTH (Install)... No 18 9 9 Days (2 Piles/ 7 Feb 2020
Steel Pipe Impact.......... Yes ......... ......... Day). through 28
Piles. 6 Days (3 Piles/ April 2020.
Day)..
Portal Island No. 1.......... Berm Support of 36-inch Diameter DTH (install)... No 133 27 27 Days (5 Piles/ 7 Feb 2020
Excavation Steel Impact.......... Yes ......... ......... Day. through 1 June
Wall--West Side. Interlocked 13 Days (10 2020.
Pipe Piles. Piles/Day)..
Portal Island No. 1.......... Berm Support of 36-inch Diameter DTH (Install)... No 121 25 25 Days (5 Piles/ 7 Feb 2020
Excavation Steel Impact.......... Yes ......... ......... Day). through 1
Wall--East Side. Interlocked 12 Days (10 September 2020.
Pipe Piles. Piles/Day)..
Portal Island No. 1.......... Mooring Piles 36-inch Diameter Vibratory No 12 3 3 Days (5 Piles/ 7 Feb 2020
and Templates. Steel Pipe (Install & Day). through 31
Piles. Removal). October 2020.
Portal Island No. 2.......... Mooring Dolphins 12-inch Timber Vibratory No 60 9 9 Days (7 Piles/ 20 June 2020
Piles. (Install). No ......... ......... Day). through 1
Impact (if 7 Days (9 Piles/ August 2020.
needed). Day)..
Portal Island No. 2.......... Omega Trestle... 36-inch Diameter DTH (Install)... No 28 14 14 Days (2 Piles/ 1 June 2020
Steel Pipe Impact.......... Yes ......... ......... Day). through 30
Piles. 12 Days (3 Piles/ September 2020.
Day)..
Portal Island No. 2.......... Berm Support of 36-inch Diameter DTH (Install)... No 124 25 25 Days ( 5 1 July 2020
Excavation Steel Impact.......... Yes ......... ......... Piles/Day). through 6 Feb
Wall--West Side. Interlocked 13 Days (10 2021.
Pipe Piles. Piles/Day)..
[[Page 16063]]
Portal Island No. 2.......... Berm Support of 36-inch Diameter DTH (Install)... No 122 25 25 Days (5 Piles/ 10 September
Excavation Steel Impact.......... Yes ......... ......... Day). 2020 through 6
Wall--East Side. Interlocked 13 Days (10 Feb 2021.
Pipe Piles. Piles/Day)..
Portal Island No. 2.......... Mooring Piles 36-inch Diameter Vibratory No 16 3 3 Days (6 Piles/ 1 March 2020
and Templates. Steel Pipe (Install & Day). through 31
Piles. Removal). October 2020.
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Total..................................................................................... 812 Piles 198 Days
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Mitigation, monitoring, and reporting measures are described in
detail later in this document (please see Mitigation and Monitoring and
Reporting sections).
Comments and Responses
A notice of NMFS' proposal to issue an IHA to the CTJV was
published in the Federal Register on November 25, 2019 (84 FR 64847).
That notice described, in detail, the CTJV's planned activity, the
marine mammal species that may be affected by the activity, the
anticipated effects on marine mammals and their habitat, proposed
amount and manner of take, and proposed mitigation, monitoring and
reporting measures. During the 30-day public comment period NMFS
received a comment letter from the Marine Mammal Commission
(Commission). The Commission's recommendations and our responses are
provided here, and the comments have been posted online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.
Comment 1: The Commission recommends that NMFS refrain from
publishing for public comment proposed incidental harassment
authorizations which contain errors and inconsistencies in the basic
underlying information and instead return such applications to action
proponents as incomplete.
Response: NMFS thanks the Commission for its recommendation. NMFS
reviews the notices thoroughly prior to publication and, despite
certain errors noted by the Commission, publishes (in this case and
others) proposals that are based on the best scientific evidence
available and that are sufficient to facilitate public comment on our
proposed actions under the MMPA.
Comment 2: The Commission recommended that NMFS resolve differences
between Table 1 and Table 7 in the proposed IHA concerning the number
of piles driven per day
Response: The CTJV revised the project schedule and has arrived at
812 total piles driven and removed over 198 days of driving operations
as shown in Table 1 in this notice.
Comment 3: The Commission recommended that NMFS refrain from
reducing the number of piles to be installed/removed per day by 50
percent in order to calculate take by Level A harassment. If NMFS
intends to use a 50-percent reduction in the number of piles to be
installed/removed per day, the Commission recommended that NMFS
implement that reduction consistently for all pile sizes, types, and
installation/removal methods.
Response: For purposes of estimated take by Level A harassment,
NMFS assumed that the number of piles installed on a given day was 50
percent of the total planned number. Since the marine mammals proposed
for authorization are highly mobile, it is unlikely that an animal
would remain within an established Level A harassment zone during the
installation/removal of multiple piles throughout a given day. To
provide a more realistic estimate of take by Level A harassment, NMFS
assumed that an animal would occur within the injury zone for 50
percent of the driving time, which equates to 50 percent of the piles
planned for installation/removal. NMFS acknowledges the necessity of
implementing this reduction across all pile sizes, types, and
installation/removal methods and has done so as shown in Table 5.
Comment 4: In the absence of relevant recovery time data for marine
mammals, the Commission recommended that animat modeling be used to
inform the appropriate accumulation time to determine injury isopleths
and estimate takes by Level A harassment. The Commission also
recommended that NMFS continue to make this issue a priority to resolve
in the near future and consider incorporating animat modeling into its
user spreadsheet.
Response: NMFS appreciates the Commission's interest in this issue,
and considers the issue a priority.
Comment 5: The Commission recommends that NMFS consult with
acousticians regarding the appropriate source level reduction factor to
use to minimize near-field (<100 m) and far-field (>100 m) effects on
marine mammals or use the data NMFS has compiled regarding source level
reductions at 10 m for near-field effects and assume no source level
reduction for far-field effects for all relevant incidental take
authorizations.
Response: NMFS disagrees with the Commission regarding this issue,
and does not adopt the recommendation. The Commission has raised this
concern before and NMFS refers readers to our full response, which may
be found in a previous notice of issuance of an IHA (84 FR 64833,
November 25, 2019).
Comment 6: The Commission recommended that NMFS use the untruncated
seasonal densities for bottlenose dolphins from Engelhaupt et al.
(2016), consistent with the previous authorization and the July 2019
monitoring data, to estimate the numbers of Level B harassment takes.
Response: NMFS has accepted the Commission's recommendation and
will use untruncated data from Engelhaupt et al. (2016) to estimate
take of bottlenose dolphins as shown in Table 9 of this notice of
issuance.
Comment 7: The Commission reiterates programmatic recommendations
regarding NMFS' potential use of the renewal mechanism for one-year
IHAs.
Response: NMFS disagrees with the Commission's recommendations, as
stated in our previous comment responses relating to other actions,
which we incorporate here by reference (e.g., 84 FR 52464; October 2,
2019).
Changes From the Proposed IHA to the Final IHA
Stock abundance updates to Table 2 (Marine Mammal Species Likely To
Occur Near the Project Area) were made in this notice for North
Atlantic right whale, fin whale, the coastal southern migratory stock
of bottlenose dolphin, harbor porpoise, and humpback whale based on the
2019 draft Stock Assessment Report published on November 27, 2019 (84
FR 65353).
[[Page 16064]]
NMFS indicated in the Federal Register notice that the IHA would
cover in-water activities beginning in the fall 2019. However,
activities will not begin until the authorization is issued in winter
2019. NMFS also indicated in the proposed IHA Federal Register notice
that up to 888 piles would be driven and/or removed. The CTJV has since
clarified that 812 piles will be driven and/or removed over 198 days
during the effective period of the issued IHA. The construction
schedule has been revised and now includes in-water activity over 11
months, with none in February, instead of 10 months of activity, with
none in September or October as indicated in the proposed IHA Federal
Register notice. Additionally, there will be no vibratory removal of
12-in timber piles as described in the proposed IHA. Temporary 12-in
timber piles will either be cut off at the mudline or undergo vibratory
removal as part of future work for which a separate IHA may be
requested. While vibratory installation of timber piles will occur,
there are no references to vibratory removal of 12-in timber piles in
this Federal Register notice of issuance.
NMFS indicated in the proposed Federal Register notice that the
source level for impact driving of 12-in piles originated from the
Ballena project described in Caltrans (2015). However, that referenced
source level came from only a single pile. The correct source levels
according to Caltrans (2015) are 180 dB re 1 [mu]Pa peak, 170 dB re 1
[mu]Pa rms, and 160 dB re 1 [mu]Pa2-sec at 10 m. NMFS has included the
updated information in Table 4 and Table 5 of this notice and updated
the Level A and B harassment zones and numbers of takes accordingly.
NMFS incorrectly specified in Table 9 of the proposed IHA Federal
Register notice the Level B harassment zone for impact installation of
36-in piles as 1,555 m rather than 1,585 m and for vibratory
installation/removal of 12-in timber piles as 1,354 m rather than 1,359
m. NMFS has made the appropriate corrections to Table 7 of this notice
and revised numbers of takes accordingly.
NMFS has included in the issued IHA a requirement that at least two
protected species observers (PSOs) will be required to monitor before,
during, and after the proposed pile-driving and -removal activities.
NMFS has included language requiring extrapolation of the numbers
of Level A harassment takes in the issued IHA as well Level B
harassment takes based on the extents of the zones that could be
monitored. Finally, take numbers for all authorized species have been
revised and are described in the Estimated Take section and listed in
Table 10.
Description of Marine Mammals in the Area of Specified Activities
Table 2 lists all species with expected potential for occurrence
near the project area 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, we
follow Committee on Taxonomy (2019). 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's 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's 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's 2018 United States Atlantic and Gulf of Mexico Marine Mammal
Stock Assessments (Hayes et al. 2019) and draft 2019 United States
Atlantic and Gulf of Mexico Marine Mammal Stock Assessments published
in the Federal Register on November 27, 2019 (84 FR 65353). All values
presented in Table 2 are the most recent available at the time of
publication and are available in the 2018 SAR and draft 2019 SAR.
Table 2--Marine Mammal Species Likely To Occur Near 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 Mysticeti (baleen whales)
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Family Balaenidae:
North Atlantic right whale \5\...... Eubalaena glacialis.... Western North Atlantic E, D; Y 428 (0, 418; See SAR). 0.8 5.55
(WNA).
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Gulf of Maine.......... -,-; N 1,380 (0; 1,380, see 22 12.15
SAR).
Fin whale \5\................... Balaenoptera physalus.. WNA.................... E,D; Y 7,418 (0.25; 6,029; 12 2.35
See SAR).
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Bottlenose dolphin.............. Tursiops truncatus..... WNA Coastal, Northern -,-; Y 6,639 (0.41; 4,759; 48 6.1-13.2
Migratory. 2011).
....................... WNA Coastal, Southern -,-; Y 3,751 (0.06; 2,353; 23 0-14.3
Migratory. 2011).
....................... Northern North Carolina -,-; Y 823 (0.06; 782; See 7.8 0.8-18.2
Estuarine System. SAR).
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -, -; N 95,543 (0.31; 74,034; 851 217
Fundy. See SAR).
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[[Page 16065]]
Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... WNA.................... -; N 75,834 (0.1; 66,884, 2,006 350
2012).
Gray seal \4\................... Halichoerus grypus..... WNA.................... -; N 27,131 (0.19, 23,158, 1,359 5,410
See SAR).
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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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ The NMFS stock abundance estimate applies to U.S. population only, however the actual stock abundance is approximately 505,000.
\5\ Species are not expected to be taken or authorized for take.
A detailed description of the of the species likely to be affected
by the planned project, including brief introductions to the species
and relevant stocks as well as available information regarding
population trends and threats, and information regarding local
occurrence, were provided in the Federal Register notice for the
proposed IHA (84 FR 64847; November 25, 2019) for additional
information. Since that time the draft 2019 United States Atlantic and
Gulf of Mexico Marine Mammal Stock Assessments has been released (84 FR
65353; November 27, 2019). Updates from the draft SAR have been
incorporated for the North Atlantic right whale, fin whale, the coastal
southern migratory stock of bottlenose dolphin, harbor porpoise, and
humpback whale. We are not aware of any additional changes in the
status of these species and stocks; therefore, detailed descriptions
are not provided here. Please refer to that Federal Register notice for
these descriptions. Please also refer to NMFS' website (https://
www.fisheries.noaa.gov/find-species) for generalized species accounts.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
Underwater noise from impact pile driving, vibratory pile driving,
vibratory pile removal, and drilling with a DTH hammer associated with
the PTST project have the potential to result in harassment of marine
mammals in the vicinity of the action area. The Federal Register notice
for the proposed IHA (84 FR 64847; November 25, 2019) included a
discussion of the potential effects of such disturbances on marine
mammals and their habitat, therefore that information is not repeated
in detail here; please refer to the Federal Register notice (84 FR
64847; November 25, 2019) for that information.
Estimated Take
This section provides an estimate of the number of incidental takes
authorized through this IHA, which informs 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 will primarily be by Level B harassment, as use of
the acoustic sources (i.e., pile driving, DTH drilling) has the
potential to result in disruption of behavioral patterns for individual
marine mammals. There is also some potential for auditory injury (Level
A harassment) to result, for phocids (harbor seals, gray seals) mid-
frequency species (bottlenose dolphins) and high-frequency species
(harbor porpoises) due to the size of the predicted auditory injury
zones. The planned mitigation and monitoring measures (see Mitigation
and Monitoring and Reporting sections below) are expected to minimize
the severity of such taking to the extent practicable. As described
previously, no mortality is anticipated or authorized for this
activity. Below we describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
and the number of days of activities. We note 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, we describe the
factors considered here in more detail and present the take estimate.
Acoustic Thresholds
Using the best available science, NMFS has developed acoustic
thresholds that identify the received level of underwater sound above
which exposed marine mammals would be reasonably expected to be
behaviorally harassed (equated to Level B harassment) or to incur PTS
of some degree (equated to Level A harassment).
Level B Harassment 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
[[Page 16066]]
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 we consider Level B 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) and
above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g.,
seismic airguns) or intermittent (e.g., scientific sonar) sources. The
CTJV's planned activity includes the use of continuous (vibratory pile
driving) and impulsive (impact pile driving, DTH drilling) sources, and
therefore the 120 and 160 dB re 1 [mu]Pa (rms) thresholds are
applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The CTJV's planned activity includes the
use includes the use of continuous (vibratory pile driving) and
impulsive (impact pile driving, DTH drilling) sources.
These thresholds are provided in Table 3 below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS 2018 Technical Guidance, which may be accessed at
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 Cell 8: LE,PW,24h: 201 dB.
dB;LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak 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 (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the planned project. Pile
driving generates underwater noise that can potentially result in
disturbance to marine mammals in the project area. The maximum
(underwater) area ensonified is determined by the topography of the Bay
including shorelines to the west south and north as well as by hard
structures such as portal islands.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B * Log 10 (R 1/R 2),
Where:
TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement
This formula neglects loss due to scattering and absorption, which
is assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (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
the PTST project site where water generally increases with depth as the
receiver moves away from pile driving locations, resulting in an
expected propagation environment that would lie between spherical and
cylindrical spreading loss conditions. Practical spreading loss is
assumed here.
The intensity of pile driving sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. In order to calculate
distances to the Level A harassment and Level B harassment thresholds
for the 36-inch steel piles planned in this project, the CTJV used
acoustic monitoring data from other locations as described in Caltrans
2015 for impact and vibratory driving. The CTJV also conducted their
[[Page 16067]]
own sound source verification testing on 42-inch steel casings as
described below to determine source levels associated with DTH
drilling. NMFS used vibratory driving of 36-in steel pile source levels
for vibratory driving of 42-inch casings source levels. The CTJV plans
to employ bubble curtains during impact driving of 36-inch steel piles
and, therefore, reduced the source level by 7 dB (a conservative
estimate based on several studies including Austin et al. 2016).
Source levels for drilling with a DTH hammer were field verified at
the PTST project site by JASCO Applied Sciences in July 2019 (Denes,
2019). Underwater sound levels were measured during drilling with a DTH
hammer at five pile locations--three without bubble curtain attenuation
and two with bubble curtain attenuation. The average SPL value at 10 m
for the DTH location without a bubble curtain was 180 dB re 1[mu]Pa,
while the average SEL and PK levels were 164 dB re 1[mu]Pa2[middot]s
and 190 dB re 1[mu]Pa, respectively. These values were greater than DTH
testing done at a location in Alaska (Denes et al. 2016). The dominant
signal characteristic was also found to be impulsive rather than
continuous. Southall et al. (2007) suggested that impulsive sounds can
be distinguished from non-impulsive sounds by comparing the SPL of a
0.035 s window that includes the pulse and with a 1 s window that may
include multiple pulses. If the SPL of the 0.035 s window is 3 dB
greater than the 1 s window, then the signal should be considered
impulsive. Denes (2019) observed that at the PTST site, the SPL of the
0.035 s pulse is 5 dB higher than the SPL of the 1 s sample, so the DTH
source is classified here as impulsive. Source levels associated with
DTH drilling of 42-inch steel casings were assumed to be the same as
recorded for installation of 36-in steel pipe by DTH.
The CTJV utilized in-water measurements generated by the Greenbusch
Group (2018) from the WSDOT Seattle Pier 62 project (83 FR 39709) to
establish proxy sound source levels for vibratory installation of 12-
inch timber piles. NMFS reviewed the report by the Greenbusch Group
(2018) and determined that the findings were derived by pooling
together all steel pile and timber pile at various distance
measurements data together. The data was not normalized to the standard
10 m distance. NMFS analyzed source measurements at different distances
for all 63 individual timber piles that were removed and normalized the
values to 10 m. The results showed that the median is 152 dB SPLrms.
This value was used as the source level for vibratory installation of
12-inch timber piles. Source levels for impact driving of 12-in timber
piles were from the Ballena Bay Marina project in Alameda, CA as
described in Caltrans 2015 but have been revised in this document. The
lower values contained in the proposed IHA notice were from a single
pile at the Ballena Bay Marina and did not reflect the measurements
from all of the piles that were tested. Sound source levels used to
calculate take are shown in Table 4.
Table 4--The Sound Source Levels (dB Peak, dB RMS, and dB sSEL) by Hammer Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated
single
Estimated Estimated strike
Type of pile Hammer type peak noise pressure sound Relevant piles at the Pile function
level (dB level (dB exposure PTST project
peak) RMS) level (dB
sSEL)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch Steel Pipe................... Impact \a\.............. 210 193 183 Plumb.................. Omega Trestle,
Temporary Dock, Berm
Wall West, and Berm
Wall East.
Impact with Bubble 203 186 176 Plumb.................. Berm Wall West, Berm
Curtain \b\. Wall East, and
Temporary Dock.
DTH--Impulsive \d\...... 190 180 164 Plumb.................. Omega Trestle, Berm
Wall West, and Berm
Wall East.
Vibratory \a\........... NA 170 170 Pipe Piles............. Mooring Piles and
Templates.
12-inch Timber Pile.................. Vibratory \c\........... NA 152 152 Plumb.................. Mooring Dolphins.
Impact \a\.............. 180 170 160 Plumb.................. Mooring Dolphins.
42-inch Steel Casing................. DTH--Impulsive \d\...... 190 180 164 Steel Casing........... Temporary Dock.
Vibratory \a\........... NA 170 170 Pipe Piles............. Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: sSEL = Single Strike Exposure Level; dB = decibel; N/A = not applicable.
\a\ Caltrans 2015.
\b\ 7 dB reduction was assumed for use an encased bubble curtain (Austin et al. 2016).
\c\ Greenbusch Group 2018.
\d\ Denes et al. 2019.
The CTJV used NMFS' Optional User Spreadsheet, available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance, to input project-specific
parameters and calculate the isopleths for the Level A harassment zones
for impact and vibratory pile driving. When the NMFS Technical Guidance
(2016) was published, in recognition of the fact that ensonified area/
volume could be more technically challenging to predict because of the
duration component in the new thresholds, we 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. We note that because of some of the assumptions
included in the methods used for these tools, we anticipate 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 source pile driving, the NMFS User
Spreadsheet predicts the distance at which, if a marine mammal remained
at that distance the whole duration of the activity, it would incur
PTS.
Table 5 provides the sound source values and input employed in the
User Spreadsheet to calculate harassment isopleths for each source type
while
[[Page 16068]]
Table 6 shows distances to Level A harassment isopleths. Note that the
isopleths calculated using the planned number of piles driven per day
is conservative. PTS is based on accumulated exposure over time.
Therefore, an individual animal would have to be within the calculated
PTS zones when all of the piles of a single type and driving method are
being actively installed throughout an entire day. The marine mammals
authorized for take are highly mobile. It is unlikely that an animal
would remain within the PTS zone during the installation of, for
example, 10 piles over an 8-hour period. NMFS opted to reduce the
number of piles driven per day by 50 percent in order to derive more
realistic PTS isopleths. In cases where the number of planned piles per
day was an odd number, NMFS used the next largest whole number that was
greater than 50 percent. These are shown in Table 5 in the row with the
heading Number of piles/day. Table 6 contains calculated distances to
PTS isopleths and Table 7 depicts distances to Level B harassment
isopleths.
Table 5--User Spreadsheet Input Parameters Used for Calculating Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
12-in timber 36-in and 42-in steel
------------------------------------------------------------------------------------------------
Model parameter Impact--with DTH--
Vibratory Impact Vibratory Impact bubble DTH simultaneous
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab........................................ A.1 E.1 A.1 E.1 E.1 E.1 E.1
Weighting Factor (kHz)................................. 2.5 2 2.5 2.0 2.0 2.0 2.0
RMS (dB)............................................... 152 170 170 193 186 180 180
Peak/SEL (dB).......................................... na 180/160 na 210/183 203/176 190/164 190/164
Number of piles/day *.................................. 4 5 3 5 5 3 3
Duration to drive a pile (minutes)..................... 30 na 12.0 na na na na
Propagation............................................ 15 15 15 15 15 15 15
Distance from source (meters).......................... 10 10 10 10 10 10 10
Strikes per pile....................................... na 1000 na 1,000 1000 25,200 50,400
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Represents 50% of piles planned per day.
Table 6--Radial Distance to PTS Isopleths (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hammer type Low-frequency Mid-frequency High-frequency Phocid pinnipeds
----------------------------------------------------- cetaceans cetaceans cetaceans -------------------- Pile location in
------------------------------------------------------------ the PTST project
Pile type Island 1 Island 2 Island 1 Island 2 Island 1 Island 2 Island 1 Island 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact.......................... 12-in. Timber..... 86 86 3 3 102 102 46 46 Mooring Dolphins.
Impact with Bubble Curtain...... 36-in. Steel...... 2,920 2,920 104 104 3,478 3,478 1,563 1,563 Omega Trestle,
Temporary Dock,
Berm Wall West,
and Berm Wall
East.
Impact with Bubble Curtain...... 36-in. Steel...... 997 997 36 36 1,188 1,188 534 534 Berm Wall West,
Berm Wall East,
and Temporary
Dock.
DTH--Impulsive.................. 36 and 42-in. 966 966 34 34 1,151 1,151 517 517 Casing for
Steel. Temporary Dock.
DTH Simultaneous................ 1,534 1,534 55 55 1,827 1,827 821 821 Omega Trestle,
Temporary Dock,
Berm Wall West,
and Berm Wall
East.
DTH & Impact Hammer (Bubble 36-and 42-in. 1,963 1,963 70 70 2,399 2,399 1,051 1,051 Omega Trestle,
Curtain) Simultaneous. Steel. Temporary Dock,
Berm Wall West,
and Berm Wall
East.
12-in. Timber..... 3 3 0.2 0.2 4 4 2 2 Mooring Dolphins.
Continuous (Vibratory).......... 36-in. Steel...... 19 19 2 2 29 29 12 12 Mooring Piles and
Templates.
42-in. Steel...... 19 ........ 2 ........ 29 ........ 12 ........ Casing for
Temporary Dock.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 7--Radial Distance (meters) to Level B Harassment Monitoring Isopleths
----------------------------------------------------------------------------------------------------------------
Distance from
Driving method Pile type Island 1 & 2 Pile location
----------------------------------------------------------------------------------------------------------------
Impact................................ 12-in. Timber............ 22 Mooring Dolphins.
36-in. Steel............. 1,585 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
Impact with Bubble Curtain............ 36-in. Steel............. 541 Berm Wall West, Berm Wall
East, and Temporary Dock.
DTH--Impulsive........................ 42-in. Steel............. * 215 Casing for Temporary Dock.
36-in. Steel............. 215 Omega Trestle, Temporary
Dock, Berm Wall West, and
Berm Wall East.
Continuous (Vibratory)................ 12-in. mooring........... 1,359 Mooring Dolphins.
36-in. Steel............. 21,544 Mooring Piles and Templates.
42-in. Steel............. * 21,544 Casing for Temporary Dock.
----------------------------------------------------------------------------------------------------------------
* Activity will not occur on Portal Island 2.
[[Page 16069]]
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide the information about the presence,
density, or group dynamics of marine mammals and describe how it is
brought together with the information above to produce a quantitative
take estimate. When available, peer-reviewed scientific publications
were used to estimate marine mammal abundance in the project area. In
some cases population estimates, densities, and other quantitative
information are lacking. Local observational data and estimated group
size were utilized where applicable.
Humpback Whale
Humpback whales are relatively rare in the Chesapeake Bay and
density data for this species within the project vicinity were not
available nor able to be calculated. Populations in the mid-Atlantic
have been estimated for humpback whales off the coast of New Jersey
with a density of 0.000130 per square kilometer (Whitt et al. 2015).
Habitat-based density models produced by the Duke University Marine
Geospatial Ecology Laboratory (Roberts et al. 2016) represent the best
available information regarding marine mammal densities offshore near
the mouth of the Chesapeake Bay. At the closest point to the PTST
project area, humpback densities ranged from a high of 0.107/100 km\2\
in March to 0.00010/100 km\2\ in August. Furthermore, the CTJV
conducted marine mammal monitoring during SSV testing for 5 days in
July 2019. During that time there were no sightings or takes of
humpback whales.
Because humpback whale occurrence is low as demonstrated above, the
CTJV and NMFS estimated that there will be a single humpback sighting
every two months for the duration of in-water pile driving activities.
Only 10 months of in-water construction were anticipated when the
proposed IHA was published, resulting in the proposed take of 10
animals. A revised construction schedule has been developed by the CTJV
and includes 11 months of planned in-water pile driving activity. Using
an average group size of two animals, pile driving activities over an
11-month period would result in 12 takes (rounding up) of humpback
whale by Level B harassment. No takes by Level A harassment are
expected or authorized.
Bottlenose Dolphin
Expected bottlenose dolphin take was estimated using a 2016 report
on the occurrence, distribution, and density of marine mammals near
Naval Station Norfolk and Virginia Beach, Virginia (Engelhaupt et al.
2016). Three years of dolphin survey data were collected from either
in-shore or open ocean transects. In the proposed IHA, a subset of
survey data from Engelhaupt et al. (2016) was used to determine
seasonal dolphin densities in the Bay near the project area. A
spatially refined approach was employed by plotting dolphin sightings
within 12 km of the project location and then determining densities
following methodology outlined in Engelhaupt et al. (2016) and Miller
et al. (2019) using the package DISTANCE in R statistical software. The
Commission believes that use of this truncated data was inappropriate
since Engelhaupt et al. (2016) did not survey all of the area near the
project site, but only surveyed within approximately 4 km of the coast.
The Commission determined that this approach was flawed as it was not
based on distance sampling methods and did not assume equal survey
effort within the harassment zones, since the majority of the
identified harassment zones had no survey effort. In response, NMFS
indicated that it would use Engelhaupt et al. (2016) data to expand the
truncated area using from 12 km to 19 km. The Commission felt that this
was also inappropriate as monitoring data from the CTJV's site
indicated that the densities provided by Engelhaupt et al. (2016) were
closer to what was actually observed at the project area compared to
the truncated Engelhaupt et al. (2016) data. The CTJV's sightings data
from July 2019 recorded an average density of animals sighted of 4.37
dolphins/km\2\. That density is actually greater than the original,
untruncated Engelhaupt et al. (2016) density of 3.88 dolphins/km\2\ for
summer. The observed 4.37 dolphins/km\2\ is much greater than the
truncated estimate of 0.62 dolphins/km\2\ utilized in the notice of
proposed IHA which was initially used to estimate take numbers. Given
this information, it is likely that the number of takes estimated in
the proposed IHA is far less than what is expected to be observed.
Therefore, NMFS opted to use the original seasonal density values
documented by Engelhaupt et al. (2016). These values were broken out by
month as shown Table 9. The Level B harassment area for each pile and
driving type as shown in Table 8 was multiplied by the appropriate
seasonal density and the anticipated number of days of a specific
activity per month number to derive a total number of takes for each
construction project component as shown in Table 9 (i.e. mooring
cluster, temporary dock, omega trestle/west O-pile walls/mooring piles
& templates, and omega trestle/east O-pile walls).
Table 8--In-Water Area (km\2\) Used for Calculating Dolphin Takes per Construction Components per Hammer Type
----------------------------------------------------------------------------------------------------------------
Vibratory Impact + DTH DTH + DTH
Construction component Pile type Impact hammer hammer hammers hammers
----------------------------------------------------------------------------------------------------------------
Mooring Cluster............... 12-in Timber.... 0.003 4.16 NA NA
Temporary Dock................ 36-in and 42-in * 0.63 830 1.72 0.25
Steel.
Omega Trestle and West O-pile 36-in and 42-in .............. 830 1.72 0.49
wall. Steel
East O-pile Wall.............. 36-in and 42-in .............. NA 1.43 0.31
Steel
----------------------------------------------------------------------------------------------------------------
* Impact Hammer with Bubble Curtain.
Table 9--Estimated Takes of Bottlenose Dolphin by Level B Harassment by Month and Driving Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Month
----------------------------------------------------------------------------------------------------------------------
March April May June July August September October November December January February
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dolphin Density (n/km\2\)........................................ 1 1 1 3.55 3.55 3.55 3.88 3.88 3.88 0.63 0.63 0.63 .......
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Days/Month based on Pile Driving Activity
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 16070]]
Mooring Cluster
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory--Timber Piles.......................................... 0 0 1 1 0 0 0 0 0 0 0 0 .......
Impact--Timber Piles............................................. 0 0 2 7 6 5 5 0 0 0 0 0
Dolphin Takes.................................................... 0.0 0.0 4.2 14.8 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 19
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary Dock
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
DTH+ Impact--Steel Pile.......................................... 4 11 11 4 0 0 0 0 0 0 0 0 .......
Vibratory--Steel Pile............................................ 2 3 3 2 0 0 0 0 0 0 0 0
Two DTH--Steel Pile.............................................. 0 0 0 0 0 0 0 0 0 0 0 0
Dolphin Takes.................................................... 1,667 2,509 2,509 5,917 0 0 0 0 0 0 0 0 12,602
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Omega Trestle/West O-pile Walls/Mooring Piles & Templates
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory--Steel Pile............................................ 0 0 0 1 1 0 2 1 0 0 0 0 .......
Two DTH--Steel Pile.............................................. 1 2 2 2 2 2 2 5 0 0 0 0
DTH+ Impact--Steel Pile.......................................... 4 2 5 5 5 8 5 5 5 5 2 0
Dolphin Takes.................................................... 7 4 10 2,981 2,981 52.4 6,478.0 3,263.3 33.4 5.4 2.2 0.0 15,817
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Omega Trestle/East O-Pile Walls
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
DTH+ Impact--Steel Pile.......................................... 0 2 2 7 8 8 8 5 5 5 2 0 .......
Two DTH--Steel Pile.............................................. 0 0 0 0 2 0 1 1 1 0 0 0
Dolphin Takes.................................................... 0 3 3 36 43 41 46 29 29 5 2 0 235
Total No. of Pile Driving Days per Month......................... 11 20 26 29 24 23 23 17 11 10 4 0
------------------------------------------------------------------------------------------------------------------------------
Total Takes.................................................. ....... ...... ...... ...... ....... ....... .......... ........ .......... .......... ........ ......... 28,674
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The number of calculated takes for each of the four project
components identified in Table 9 resulted in a total of 28,674
authorized takes. The authorized takes were split out among the three
dolphin stocks as shown in Table 10. There is insufficient information
to apportion the takes precisely to the three stocks present in the
area. Given that most of the NNCES stock are found in the Pamlico Sound
estuarine system, NMFS will assume that no more than 200 of the
authorized takes will be from this stock. Since members of the northern
migratory coastal and southern migratory coastal stocks are thought to
occur in or near the Bay in greater numbers, we will conservatively
assume that no more than half of the remaining animals will accrue to
either of these stocks. Additionally, a subset of these takes would
likely be comprised of Chesapeake Bay resident dolphins, although size
of that population is unknown.
Since the largest Level A harassment isopleth is 104 m and there is
a shutdown zone of 100 m, NMFS will assume that 1 percent of each
designated stock will occur between 100 and 104 meters or will appear
in the PTS zone without first being observed by PSOs resulting in the
number of dolphin takes by Level A harassment shown in Table 10. NMFS
had not proposed take by Level A harassment in the notice of proposed
IHA. However, the Level A harassment isopleth for impact driving of 36-
in steel piles exceeds the 100-m shutdown zone and the number of
authorized takes has increased.
Harbor Porpoise
Given that harbor porpoises are uncommon in the project area, this
exposure analysis assumes that there is a porpoise sighting once during
every two months of operations which would equate to six sightings
(rounding up) over 11 months. Assuming an average group size of two
(Hansen et al. 2018; Elliser et al. 2018) over 11 months of in-water
work results in a total of 12 estimated takes of porpoises. (In the
proposed IHA, NMFS had assumed 10 months of driving resulting in 10
total takes.) Harbor porpoises are members of the high-frequency
hearing group which have Level A harassment isopleths as large as 3,478
m during impact installation of 10 36-in steel piles per day. Given the
relatively large Level A harassment zones during impact driving, NMFS
assumed in the previous IHA (83 FR 36522; July 30, 2018) that 40
percent of estimated porpoises takes would be by Level A harassment.
NMFS assumed the same ratio for the issued IHA resulting in five
authorized takes of porpoises by Level A harassment and seven takes by
Level B harassment. When the CTJV conducted marine mammal monitoring
during SSV testing at the project location for 5 days in July 2019,
there were no sightings of porpoises.
Harbor Seal
The number of harbor seals expected to be present in the PTST
project area was estimated using survey data for in-water and hauled
out seals collected by the United States Navy at the portal islands
from November 2014 through April 2018 (Rees et al., 2016; Jones et al.
2018). The survey data revealed a daily maximum of 45 animals during
this period which occurred in January, 2018. The maximum number of
animals observed per day (45) was multiplied by the total number of
planned driving days between November and May (72) since seals are not
present in the area from June through October. In the proposed IHA,
NMFS had assumed 173 days of driving during this same period. Based on
this revised calculation NMFS has authorized 3,240 incidental takes of
harbor seal for this IHA. Note that the CTJV monitoring report did not
record any seal observations over 5 days of SSV testing, but this would
be expected as seals are not present during July.
[[Page 16071]]
The largest Level A harassment isopleth for phocid species is
approximately 1,563 meters which would occur during impact driving of
36-inch steel piles. The smallest Level A harassment isopleths are 2 m
and would occur during impact and vibratory driving of 12-inch timber
piles. NMFS has prescribed a shutdown zone for harbor seals of 15
meters as a mitigation measure since seals are common in the project
area and are known to approach the shoreline. A larger shutdown zone
would likely result in multiple shutdowns and impede the project
schedule. From the previously issued IHA, NMFS assumed that 40 percent
of the exposed seals will occur within the Level A harassment zone
specified for a given scenario and the remaining affected seals would
result in Level B harassment takes. Therefore, NMFS has authorized
1,296 takes by Level A harassment and 2,124 takes by Level B
harassment.
Gray Seal
The number of gray seals expected to be present at the PTST project
area was estimated using survey data collected by the U.S. Navy at the
portal islands from 2014 through 2018 (Rees et al. 2016; Jones et al.
2018). One seal was observed in February of 2015 and one seal was
recorded in February of 2016 while no seals were observed at any time
during 2017 or 2018. As part of the proposed IHA, NMFS anticipated gray
seals would occur only during the 21 planned work days for February at
a rate of one animal per day. Due to revisions to the construction
schedule, no in-water pile driving is scheduled to occur in February
under the effective period for this IHA. However, there could be delays
to the construction schedule resulting in the need for in-water work in
February 2021. To reduce the possibility that non-authorized take of
gray seal could result in work stoppage, NMFS has conservatively
authorized take of four gray seals, one by Level A harassment and three
by Level B harassment.
Table 10 shows authorized take numbers for Level A and Level B
harassment.
Table 10--Authorized Take by Level A and Level B Harassment
----------------------------------------------------------------------------------------------------------------
Percentage of
Species Stock Level A takes Level B takes stock
----------------------------------------------------------------------------------------------------------------
Humpback whale........................ Gulf of Maine........... .............. 12 0.8
Harbor porpoise....................... Gulf of Maine/Bay of 5 7 <0.01
Fundy.
Bottlenose dolphin.................... WNA Coastal, Northern 142 14,095 \*\ <33
Migratory.
WNA Coastal, Southern 142 14,095 \*\ <33
Migratory.
NNCES................... 2 198 24
Harbor seal........................... Western North Atlantic.. 1,296 2,124 4.5
Gray seal............................. Western North Atlantic.. 1 3 <0.01
----------------------------------------------------------------------------------------------------------------
* Assumes multiple repeated takes of same individuals from small portion of each stock as well as repeated takes
of Chesapeake Bay resident population (size unknown).
Mitigation
In order to issue an IHA under Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to 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 (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting 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, we
carefully consider 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
CTJV will employ the following standard mitigation measures:
Conduct briefings between construction supervisors and
crews and the marine mammal monitoring team prior to the start of all
pile driving activity, and when new personnel join the work, to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures;
For in-water heavy machinery work other than pile driving
(e.g., standard barges, etc.), 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. This
type of work could include the following activities: (1) Movement of
the barge to the pile location; or (2) positioning of the pile on the
substrate via a crane (i.e., stabbing the pile);
Work may only occur during daylight hours, when visual
monitoring of marine mammals can be conducted;
For those marine mammals for which Level B harassment take
has not been requested, in-water pile driving will shut down
immediately if such species are observed within or entering the
monitoring zone (i.e., Level B harassment zone); and
If take reaches the authorized limit for an authorized
species, pile installation will be stopped as these species approach
the Level B harassment zone to avoid additional take.
The following measures will apply to the CTJV's mitigation
requirements:
Establishment of Shutdown Zone--For all pile driving and drilling
[[Page 16072]]
activities, the CTJV will establish a shutdown zone. The purpose of a
shutdown zone is generally to define an area within which shutdown of
activity will occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). These shutdown
zones will be used to reduce incidental Level A harassment from impact
pile driving for bottlenose dolphins and harbor porpoises. Shutdown
zones for species authorized for take are as follows:
100 meters for harbor porpoise and bottlenose dolphin.
15 meters for harbor seal and gray seal.
For humpback whale, shutdown distances are shown in Table
14 under low-frequency cetaceans and are dependent on activity type.
Establishment of Monitoring Zones for Level A and Level B
Harassment--The CTJV will establish monitoring zones based on
calculated Level A harassment isopleths associated with specific pile
driving activities and scenarios. These are areas beyond the
established shutdown zone in which animals could be exposed to sound
levels that could result in Level A harassment in the form of PTS. The
CTJV will also establish and monitor Level B harassment zones which are
areas where SPLs are equal to or exceed the 160 dB rms threshold for
impact driving and DTH drilling and 120 dB rms threshold during
vibratory driving. Monitoring zones provide utility for observing by
establishing monitoring protocols for areas adjacent to the shutdown
zones. The monitoring zones enable observers to be aware of and
communicate the presence of marine mammals in the project area outside
the shutdown zone and thus prepare for a potential cease of activity
should the animal enter the shutdown zone. The Level A and Level B
harassment monitoring zones are described in Table 11. Since some of
the Level A and Level B harassment monitoring zones cannot be
effectively observed in their entirety, exposures will be recorded and
extrapolated based upon the number of observed take and the percentage
of the Level A and Level B harassment zone that was not visible.
Table 11--Level A and Level B Harassment Monitoring Zones During Project Activities (meters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Scenario Level A harassment zones Level B
---------------------------------------------------------------------------------------------------------------------------------------- monitoring
Low-frequency Mid-frequency High-frequency Phocid zones
cetaceans cetaceans cetaceans pinnipeds ----------------
Driving type Pile type --------------------------------------------------------------------
Island 1 & 2 Island 1 & 2 Island 1 & 2 Island 1 & 2 Island 1 & 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact................................. 12-in. Timber............. 90 -- 105 -- 25.
36-in. Steel.............. 2,920 105 3,480 1,565 1,585.
Impact with Bubble Curtain............. 36-in. Steel.............. 1,000 -- 1,190 535 545.
DTH--Impulsive......................... 42-in. Steel.............. 970 -- 1,155 520 215.
DTH Simultaneous at same island........ 42-in. Steel.............. 1,535 -- 1,830 825 215.
DTH & Impact Hammer with bubble 36-and 42-in. Steel....... 1,970 -- 2,400 1,055 545.
curtain: Simultaneous at the same
island.
DTH at PI 1. And Impact with Bubble 36-and 42-in. Steel....... 970 -- 1,155 520 215 from PI 1.
Curtain Hammer at PI 2. 545 from PI 2.
Continuous (Vibratory)................. 12-in. Timber............. -- -- -- -- 1,360.
36-in. Steel.............. 20 -- -- -- 21,545.
42-in.** Steel............ 20 -- -- -- 21,545.
--------------------------------------------------------------------------------------------------------------------------------------------------------
-- indicates that shutdown zone is larger than calculated harassment zone.
** Activity only planned at Portal Island 1 as part of project pile driving plan.
Soft Start--The use of soft-start procedures are believed to
provide additional protection to marine mammals by providing warning
and/or giving marine mammals a chance to leave the area prior to the
hammer operating at full capacity. For impact pile driving, contractors
will be required to provide an initial set of strikes from the hammer
at reduced energy, with each strike followed by a 30-second waiting
period. This procedure will be conducted a total of three times before
impact pile driving begins. 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. Soft start
is not required during vibratory or DTH pile driving activities.
Use of Bubble Curtains--Use of air bubble curtain system will be
implemented by the CTJV during impact driving of 36-in steel piles
except in water less than 10 ft in depth. The use of this sound
attenuation device will reduce SPLs and the size of the zones of
influence for Level A harassment and Level B harassment. Bubble
curtains will meet the following requirements:
The bubble curtain must distribute air bubbles around 100
percent of the piling perimeter for the full depth of the water column.
The lowest bubble ring shall be in contact with the
mudline and/or rock bottom for the full circumference of the ring, and
the weights attached to the bottom ring shall ensure 100 percent
mudline and/or rock bottom contact. No parts of the ring or other
objects shall prevent full mudline and/or rock bottom contact.
The bubble curtain shall be operated such that there is
proper (equal) balancing of air flow to all bubblers.
The applicant shall require that construction contractors
train personnel in the proper balancing of air flow to the bubblers and
corrections to the attenuation device to meet the performance
standards. This shall occur prior to the initiation of pile driving
activities.
Pre-Activity Monitoring--Prior to the start of daily in-water
construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs will observe the shutdown and monitoring
zones for a period of 30 minutes. The shutdown zone will be cleared
when a marine mammal has not been observed within the zone for that 30-
minute period. If a marine mammal
[[Page 16073]]
is observed within the shutdown zone, a soft-start cannot proceed until
the animal has left the zone or has not been observed for 15 minutes.
If the Level B harassment zone has been observed for 30 minutes and
non-permitted species are not present within the zone, soft start
procedures can commence and work can continue even if visibility
becomes impaired within the Level B harassment monitoring zone. When a
marine mammal permitted for take by Level B harassment is present in
the Level B harassment zone, activities may begin and Level B
harassment take will be recorded. If work ceases for more than 30
minutes, the pre-activity monitoring of both the Level B harassment and
shutdown zone will commence again. Additionally, in-water construction
activity must be delayed or cease, if poor environmental conditions
restrict full visibility of the shut-down zone(s) until the entire
shut-down zone(s) is visible.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the required mitigation measures provide the means
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
planned 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:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
Marine Mammal Visual Monitoring
Monitoring shall be conducted by NMFS-approved observers. Trained
observers shall be placed from the best vantage point(s) practicable to
monitor for marine mammals and implement shutdown or delay procedures
when applicable through communication with the equipment operator.
Observer training must be provided prior to project start, and shall
include instruction on species identification (sufficient to
distinguish the species in the project area), description and
categorization of observed behaviors and interpretation of behaviors
that may be construed as being reactions to the specified activity,
proper completion of data forms, and other basic components of
biological monitoring, including tracking of observed animals or groups
of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
Monitoring will be conducted 30 minutes before, during, and 30
minutes after pile driving activities. In addition, observers shall
record all incidents of marine mammal occurrence, regardless of
distance from activity, and shall document any behavioral reactions in
concert with distance from piles being driven. Pile driving activities
include the time to install a single pile or series of piles, as long
as the time elapsed between uses of the pile driving equipment is no
more than 30 minutes. The CTJV will be required to station between two
and four PSOs at locations offering the best available views of the
monitoring zones. At least two PSOs will be required to monitor before,
during, and after the pile-driving and -removal activities. At least
one PSO must be located in close proximity to each pile driving rig
during active operation of single or multiple, concurrent driving
devices. At least one additional PSO is required at each active driving
rig or other location providing best possible view if the Level B
harassment zone and shutdown zones cannot reasonably be observed by one
PSO.
PSOs will scan the waters using binoculars, and/or spotting scopes,
and will use a handheld GPS or range-finder device to verify the
distance to each sighting from the project site. All PSOs will be
trained in marine mammal identification and behaviors and are required
to have no other project-related tasks while conducting monitoring. In
addition, monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. The CTJV will
adhere to the following PSO qualifications:
(i) Independent observers (i.e., not construction personnel) are
required.
(ii) At least one observer must have prior experience working as an
observer.
(iii) Other observers may substitute education (degree in
biological science or related field) or training for experience.
(iv) Where a team of three or more observers are required, one
observer shall be designated as lead observer or monitoring
coordinator. The lead observer must have prior experience working as an
observer.
(v) The CTJV shall submit observer CVs for approval by NMFS.
Additional standard observer qualifications include:
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals
[[Page 16074]]
observed within a defined shutdown zone; and marine mammal behavior;
and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Observers will be required to use approved data forms. Among other
pieces of information, The CTJV will record detailed information about
any implementation of shutdowns, including the distance of animals to
the pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, the CTJV will attempt to
distinguish between the number of individual animals taken and the
number of incidences of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity, and if possible, the correlation to SPLs;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Description of implementation of mitigation measures
(e.g., shutdown or delay);
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report will be submitted to NMFS within 90 days of the
completion of marine mammal monitoring, or 60 days prior to the
requested date of issuance of any future IHA for projects at the same
location, whichever comes first. The report will include marine mammal
observations pre-activity, during-activity, and post-activity during
pile driving days (and associated PSO data sheets), and will also
provide descriptions of any behavioral responses to construction
activities by marine mammals and a complete description of all
mitigation shutdowns and the results of those actions and an
extrapolated total take estimate based on the number of marine mammals
observed during the course of construction. A final report must be
submitted within 30 days following resolution of comments on the draft
report.
Reporting Injured or Dead Marine Mammals
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the CTJV shall report the
incident to the Office of Protected Resources (OPR), NMFS and to the
Greater Atlantic Region New England/Mid-Atlantic Regional Stranding
Coordinator as soon as feasible. The report must include the following
information:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any 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. We also assess the number, intensity, and context of
estimated takes by evaluating this information relative to population
status. Consistent with the 1989 preamble for NMFS's 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 activities associated with the planned PTST project,
as outlined previously, have the potential to disturb or displace
marine mammals. The specified activities may result in take, in the
form of Level B harassment (behavioral disturbance) or Level A
harassment (auditory injury), incidental to underwater sounds generated
from pile driving. Potential takes could occur if individuals are
present in the ensonified zone when pile driving occurs. Level A
harassment is anticipated for bottlenose dolphins, harbor porpoises,
harbor seals, and gray seals.
No serious injury or mortality is anticipated given the nature of
the activities and measures designed to minimize the possibility of
injury to marine mammals. The potential for these outcomes is minimized
through the construction method and the implementation of the planned
mitigation measures. Specifically, vibratory driving, impact driving,
and drilling with DTH hammers will be the primary methods of
installation and pile removal will occur with a vibratory hammer.
Impact pile driving produces short, sharp pulses with higher peak
levels and much sharper rise time to reach those peaks. When impact
pile driving is used, implementation of bubble curtains, soft start and
shutdown zones significantly reduces any possibility of injury. Given
sufficient notice through use of soft starts (for impact driving),
marine mammals are expected to move away from a sound source that is
annoying prior to it becoming potentially injurious.
The CTJV will use qualified PSOs stationed strategically to
increase detectability of marine mammals, enabling a high rate of
success in implementation of shutdowns to avoid injury for most
species. PSOs will be stationed on a specific Portal Island whenever
pile driving operations are underway at that location. Additional PSOs
will be stationed at the same Portal Island and in other locations in
order to provide a relatively clear views of the shutdown zone and
monitoring zones. These factors will limit exposure of animals to noise
levels that could result in injury.
The CTJV's planned pile driving activities are highly localized.
Only a relatively small portion of the Chesapeake Bay may be affected.
Localized noise exposures produced by project activities may cause
short-term
[[Page 16075]]
behavioral modifications in affected cetaceans and pinnipeds Moreover,
the required mitigation and monitoring measures are expected to further
reduce the likelihood of injury as well as reduce behavioral
disturbances.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff
2006). Individual animals, even if taken multiple times, will most
likely move away from the sound source and be temporarily displaced
from the areas of pile driving, although even this reaction has been
observed primarily only in association with impact pile driving. The
pile driving activities analyzed here are similar to, or less impactful
than, numerous other construction activities conducted along both
Atlantic and Pacific coasts, which have taken place with no known long-
term adverse consequences from behavioral harassment. Furthermore, many
projects similar to this one are also believed to result in multiple
takes of individual animals without any documented long-term adverse
effects. Level B harassment will be minimized through use of mitigation
measures described herein and, if sound produced by project activities
is sufficiently disturbing, animals are likely to simply avoid the area
while the activity is occurring.
In addition to the expected effects resulting from authorized Level
B harassment, we anticipate that small numbers of dolphins, harbor
porpoises, harbor seals and gray seals may sustain some limited Level A
harassment in the form of auditory injury. However, animals that
experience PTS would likely only receive slight PTS, i.e. minor
degradation of hearing capabilities within regions of hearing that
align most completely with the energy produced by pile driving (i.e.,
the low-frequency region below 2 kHz), not severe hearing impairment or
impairment in the regions of greatest hearing sensitivity. If hearing
impairment occurs, it is most likely that the affected animal's
threshold would increase by a few dBs, which is not likely to
meaningfully affect its ability to forage and communicate with
conspecifics. As described above, we expect that marine mammals would
be likely to move away from a sound source that represents an aversive
stimulus, especially at levels that would be expected to result in PTS,
given sufficient notice through use of soft start.
The project is not expected to have significant adverse effects on
marine mammal habitat. No important feeding and/or reproductive areas
for marine mammals are known to be near the project area. Project
activities would not permanently modify existing marine mammal habitat.
The activities may cause some fish to leave the area of disturbance,
thus temporarily impacting marine mammal foraging opportunities in a
limited portion of the foraging range. However, because of the
relatively small area of the habitat that may be affected, the impacts
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the species or stock
through effects on annual rates of recruitment or survival:
No mortality is anticipated or authorized;
Limited Level A harassment exposures (dolphins, harbor
porpoises, harbor seals, and gray seals) are anticipated to result only
in slight PTS, within the lower frequencies associated with pile
driving;
The anticipated incidents of Level B harassment consist
of, at worst, temporary modifications in behavior that would not result
in fitness impacts to individuals;
The specified activity and associated ensonifed areas are
very small relative to the overall habitat ranges of all species and
does not include habitat areas of special significance (BIAs or ESA-
designated critical habitat); and
The presumed efficacy of the required mitigation measures
in reducing the effects of the specified activity.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the planned
activity will have a negligible impact on all affected marine mammal
species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
Authorized take of marine mammal stocks comprises less than 5
percent of the Western North Atlantic harbor seal stock abundance, and
less than one percent of all other authorized stocks, with the
exception of bottlenose dolphins. There are three bottlenose dolphin
stocks that could occur in the project area. Therefore, the estimated
28,674 dolphin takes by Level A and Level B harassment would likely be
split among the western North Atlantic northern migratory coastal
stock, western North Atlantic southern migratory coastal stock, and
NNCES stock. Based on the stocks' respective occurrence in the area,
NMFS estimated that there would be no more than 200 takes from the
NNCES stock, representing 24 percent of that population, with the
remaining takes split evenly between the northern and southern
migratory coastal stocks. Based on consideration of various factors
described below, we have determined the numbers of individuals taken
would comprise less than one-third of the best available population
abundance estimate of either coastal migratory stock. Detailed
descriptions of the stocks' ranges have been provided in Description of
Marine Mammals in the Area of Specified Activities.
Both the northern migratory coastal and southern migratory coastal
stocks have expansive ranges and they are the only dolphin stocks
thought to make broad-scale, seasonal migrations in coastal waters of
the western North Atlantic. Given the large ranges associated with
these two stocks it is unlikely that large segments of either stock
would approach the project area and enter into the Bay. The majority of
both stocks are likely to be found widely dispersed across their
respective habitat ranges and unlikely to be concentrated in or near
the Chesapeake Bay.
Furthermore, the Chesapeake Bay and nearby offshore waters
represent the boundaries of the ranges of each of the two coastal
stocks during migration. The northern migratory coastal stock is found
during warm water months from coastal Virginia, including the
Chesapeake Bay and Long Island, New York. The stock migrates south in
late summer and fall. During cold water
[[Page 16076]]
months dolphins may be found in coastal waters from Cape Lookout, North
Carolina, to the North Carolina/Virginia. During January-March, the
southern migratory coastal stock appears to move as far south as
northern Florida. From April to June, the stock moves back north to
North Carolina. During the warm water months of July-August, the stock
is presumed to occupy coastal waters north of Cape Lookout, North
Carolina, to Assateague, Virginia, including the Chesapeake Bay. There
is likely some overlap between the northern and southern migratory
stocks during spring and fall migrations, but the extent of overlap is
unknown.
The Bay and waters offshore of the mouth are located on the
periphery of the migratory ranges of both coastal stocks (although
during different seasons). Additionally, each of the migratory coastal
stocks are likely to be located in the vicinity of the Bay for
relatively short timeframes. Given the limited number of animals from
each migratory coastal stock likely to be found at the seasonal
migratory boundaries of their respective ranges, in combination with
the short time periods (~two months) animals might remain at these
boundaries, it is reasonable to assume that takes are likely to occur
only within some small portion of either of the migratory coastal
stocks.
Both migratory coastal stocks likely overlap with the NNCES stock
at various times during their seasonal migrations. The NNCES stock is
defined as animals that primarily occupy waters of the Pamlico Sound
estuarine system (which also includes Core, Roanoke, and Albemarle
sounds, and the Neuse River) during warm water months (July-August).
Members of this stock also use coastal waters (<=1km from shore) of
North Carolina from Beaufort north to Virginia Beach, Virginia,
including the lower Chesapeake Bay. Comparison of dolphin photo-
identification data confirmed that limited numbers of individual
dolphins observed in Roanoke Sound have also been sighted in the
Chesapeake Bay (Young 2018). Like the migratory coastal dolphin stocks,
the NNCES stock covers a large range. The spatial extent of most small
and resident bottlenose dolphin populations is on the order of 500
km\2\, while the NNCES stock occupies over 8,000 km\2\ (LeBrecque et
al. 2015). Given this large range, it is again unlikely that a
preponderance of animals from the NNCES stock would depart the North
Carolina estuarine system and travel to the northern extent of the
stock's range and enter into the Bay. However, recent evidence suggests
that there is likely a small resident community of NNCES dolphins of
indeterminate size that inhabits the Chesapeake Bay year-round
(Patterson, Pers. Comm).
Many of the dolphin observations in the Bay are likely repeated
sightings of the same individuals. The Potomac-Chesapeake Dolphin
Project has observed over 1,200 unique animals since observations began
in 2015. Re-sightings of the same individual can be highly variable.
Some dolphins are observed once per year, while others are highly
regular with greater than 10 sightings per year (Mann, pers. comm.).
Similarly, using available photo-identification data, Engelhaupt et al.
(2016) determined that specific individuals were often observed in
close proximity to their original sighting locations and were observed
multiple times in the same season or same year. Ninety-one percent of
re-sighted individuals (100 of 110) in the study area were recorded
less than 30 km from the initial sighting location. Multiple sightings
of the same individual would considerably reduce the number of
individual animals that are taken by harassment. Furthermore, the
existence of a resident dolphin population in the Bay would increase
the percentage of dolphin takes that are actually re-sightings of the
same individuals.
In summary and as described above, the following factors primarily
support our preliminary determination regarding the incidental take of
small numbers of a species or stock:
The take of marine mammal stocks authorized for take
comprises less than 5 percent of any stock abundance (with the
exception of bottlenose dolphin stocks);
Potential bottlenose dolphin takes in the project area are
likely to be allocated among three distinct stocks;
Bottlenose dolphin stocks in the project area have
extensive ranges and it would be unlikely to find a high percentage of
any one stock concentrated in a relatively small area such as the
project area or the Bay;
The Bay represents the migratory boundary for each of the
specified dolphin stocks and it would be unlikely to find a high
percentage of any stock concentrated at such boundaries; and
Many of the takes would be repeats of the same animal and
it is likely that a number of individual animals could be taken 10 or
more times.
Based on the analysis contained herein of the planned activity
(including the required mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS finds that small numbers of
marine mammals 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.
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 action (i.e., the issuance of incidental
harassment authorizations) with respect to potential impacts on the
human environment. This action is consistent with categories of
activities identified in Categorical Exclusion B4 (incidental
harassment authorizations with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has determined
that the issuance of this IHA to the CTJV qualifies to be categorically
excluded from further NEPA review.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat.
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.
Authorization
NMFS has issued an IHA to the CTJV for the incidental take of
marine mammal due to pile driving activities as part of the PTST
project for a period of one year from the date of issuance, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated.
[[Page 16077]]
Dated: March 10, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-05802 Filed 3-19-20; 8:45 am]
BILLING CODE 3510-22-P