[Federal Register Volume 82, Number 149 (Friday, August 4, 2017)]
[Notices]
[Pages 36360-36384]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-16453]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XF541
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Pier Replacement Project in San
Diego, CA
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for
authorization to take marine mammals incidental to construction and
demolition activities as part of a pier replacement project. Pursuant
to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments
on its proposal to issue an incidental harassment authorization (IHA)
to the Navy to incidentally take marine mammals, by Level B Harassment
only, during the specified activity. NMFS will consider public comments
prior to making any final decision on the issuance of the requested
MMPA authorizations and agency responses will be summarized in the
final notice of our decision.
DATES: Comments and information must be received no later than
September 5, 2017.
ADDRESSES: Comments on the application should be addressed to Jolie
Harrison, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service. Physical comments should
be sent to 1315 East-West Highway, Silver Spring, MD 20910 and
electronic comments should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted to the Internet at
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without
change. All personal identifying information (e.g., name, address)
voluntarily submitted by the commenter may be publicly accessible. Do
not submit confidential business information or otherwise sensitive or
protected information.
FOR FURTHER INFORMATION CONTACT: Laura McCue, 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: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
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
[[Page 36361]]
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
The MMPA states that the term ``take'' means to harass, hunt,
capture, kill or attempt to harass, hunt, capture, or kill any marine
mammal.
Except with respect to certain activities not pertinent here, 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).
National Environmental Policy Act (NEPA)
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in CE B4 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
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On June 19, 2017, we received a request from the Navy for an IHA to
take marine mammals incidental to pile installation and demolition
associated with a pier replacement project in San Diego Bay at Naval
Base Point Loma in San Diego, CA (NBPL), including a separate
monitoring plan. The Navy also submitted a draft monitoring report on
June 13, 2017, pursuant to requirements of the previous IHA. These
final application and monitoring plan were deemed adequate and complete
on July 20, 2017. The pier replacement project is planned to occur over
multiple years; this proposed IHA would cover only the fifth year of
work and would be valid for a period of one year from the date of
issuance. Hereafter, use of the generic term ``pile driving'' may refer
to both pile installation and removal unless otherwise noted. The
Navy's request is for take of nine species of marine mammals by Level B
harassment. Neither the Navy nor NMFS expect mortality to result from
this activity and, therefore, an IHA is appropriate.
Monitoring reports are available online at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm and provide environmental
information related to proposed issuance of this IHA for public review
and comment.
This proposed IHA would cover one year of a larger project for
which the Navy obtained prior IHAs and this request for take
authorization is for the fifth year of the project, following the IHAs
issued effective from October 8, 2016, through October 7, 2017 (81 FR
66628), September 1, 2013, through August 31, 2014 (78 FR 44539), from
October 8, 2014, through October 7, 2015 (79 FR 65378), and from
October 8, 2015, through October 7, 2016 (80 FR 62032). The Navy
complied with all the requirements (e.g., mitigation, monitoring, and
reporting) of the previous IHA. Monitoring reports are available online
at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm and provide
environmental information related to proposed issuance of this IHA for
public review and comment.
Description of the Specified Activity
Overview
NBPL provides berthing and support services for Navy submarines and
other fleet assets. The existing fuel pier serves as a fuel depot for
loading and unloading tankers and Navy underway replenishment vessels
that refuel ships at sea (``oilers''), as well as transferring fuel to
local replenishment vessels and other small craft operating in San
Diego Bay, and is the only active Navy fueling facility in southern
California. Portions of the pier are over one hundred years old, while
the newer segment was constructed in 1942. The pier as a whole is
significantly past its design service life and does not meet current
construction standards.
The Navy plans to demolish and remove the existing pier and
associated pipelines and appurtenances while simultaneously replacing
it with a generally similar structure that meets relevant standards for
seismic strength and is designed to better accommodate modern Navy
ships. Demolition and construction are planned to occur in two phases
to maintain the fueling capabilities of the existing pier while the new
pier is being constructed. During the fifth year of construction (the
specified activity considered under this proposed IHA), the Navy
anticipates construction at two locations: The fuel pier area and at
the Naval Mine and Anti-Submarine Warfare Command (NMAWC), where the
Navy's Marine Mammal Program (MMP) was temporarily moved during fuel
pier construction (see Figure 1-1 in the Navy's application). At the
fuel pier, the Navy anticipates finishing all the demolition, including
removal of 180 square precast (PC) concrete and poly-concrete piles of
varying sizes up to 24-in using a hydraulic pile cutter; cutting 30 66-
in and 5 84-in concrete-filled steel caissons with a diamond wire saw;
and removing 12 30-in steel piles by cutting with a plasma torch. Only
the hydraulic pile cutting and diamond saw cutting of caissons reach
Level B acoustic thresholds.
At the NMAWC, twenty-three 16-in diameter PC concrete guide piles
would be driven (by vibratory and/or impact hammer) to restore gangway
access to the recreational marina. Sixty-four 16-in diameter round PC
concrete guide piles will be removed at NMAWC by jetting followed by
dry-pulling; dry pulling does not reach the Level B acoustic
thresholds. Table 1 summarizes the construction activities during the
fifth year of the Navy's project.
[[Page 36362]]
Table 1--Construction Proposed To Be Complete During Fifth Year of NBPL
Project
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Location and pile type or structure Number
------------------------------------------------------------------------
Removal/Demolition
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Pier 180 (Fuel Pier):
Poly-concrete and PC concrete piles up to 24-in 180
square.............................................
66'' concrete filled steel caissons................. 30
84'' concrete filled steel caissons................. 5
30'' steel at temporary south dolphin............... 12
Total--Pier 180 (Fuel Pier)..................... 227
NMAWC:
Extract 16'' PC round concrete...................... 64
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Total--NMAWC.................................... 64
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Total Piles Removed......................... 291
------------------------------------------------------------------------
Installation
------------------------------------------------------------------------
NMAWC:
16'' PC concrete guide piles........................ 23
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Total Piles Removed......................... 23
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Notes: PC = precast.
The proposed actions with the potential to incidentally harass
marine mammals within the waters adjacent to NBPL are vibratory and
impact pile installation and certain demolition (i.e., pile removal)
techniques. Concurrent use of multiple pile driving rigs is not
planned.
Dates and Duration
The proposed activities that would be authorized by this IHA,
during the fifth year of work associated with the fuel pier project,
would occur for one year from the date of issuance of this proposed
IHA. Under the terms of a memorandum of understanding (MOU) between the
Navy and the U.S. Fish and Wildlife Service (FWS), all noise- and
turbidity-producing in-water activities in designated least tern
foraging habitat are to be avoided during the period when least terns
are present and engaged in nesting and foraging (a window from
approximately May 1 through September 15). However, it is possible that
in-water work not expected to result in production of significant noise
or turbidity (e.g., demolition activities) could occur at any time
during the period of validity of this proposed IHA. The conduct of any
such work would be subject to approval from FWS under the terms of the
MOU. We expect that in-water construction work would primarily occur
from October through April. Pile driving would occur during normal
working hours (approximately 7 a.m. to 6 p.m.), and would not occur
earlier than 45 minutes after sunrise or later than 45 minutes before
sunset.
Specific Geographic Region
NBPL is located on the peninsula of Point Loma near the mouth and
along the northern edge of San Diego Bay (see Figures 1-1 and 1-2 in
the Navy's application). San Diego Bay is a narrow, crescent-shaped
natural embayment oriented northwest-southeast with an approximate
length of 24 kilometers (km) and a total area of roughly 4,500 hectares
(ha). The width of the bay ranges from 0.3 to 5.8 km, and depths range
from 23 meters (m) mean lower low water (MLLW) near the tip of Ballast
Point to less than 2 m at the southern end (see Figure 2-1 of the
Navy's application). San Diego Bay is a heavily urbanized area with a
mix of industrial, military, and recreational uses. The northern and
central portions of the bay have been shaped by historic dredging to
support large ship navigation. Dredging occurs as necessary to maintain
constant depth within the navigation channel. Outside the navigation
channel, the bay floor consists of platforms at depths that vary
slightly. Sediments in northern San Diego Bay are relatively sandy as
tidal currents tend to keep the finer silt and clay fractions in
suspension, except in harbors and elsewhere in the lee of structures
where water movement is diminished. Much of the shoreline consists of
riprap and manmade structures. San Diego Bay is heavily used by
commercial, recreational, and military vessels, with an average of over
80,000 vessel movements (in or out of the bay) per year (not including
recreational boating within the Bay) (see Table 2-2 of the Navy's
application). For more information about the specific geographic
region, please see section 2.3 of the Navy's application.
Detailed Description of Activities
In order to provide context, we described the entire project in our
Federal Register notice of proposed authorization associated with the
first-year IHA (78 FR 30873; May 23, 2013). Please see that document
for an overview of the entire fuel pier replacement project, or see the
Navy's Environmental Assessment (2013) for more detail. Here, we
provide an overview of relevant construction methods before describing
only the specific project portions scheduled for completion during the
fifth work window. Please see Section 1 of the Navy's application for
full detail of construction scheduling for this period. For the fifth
year of work, approximately 23 concrete piles would be installed at
NMAWC. The Navy does not anticipate needing future IHAs related to
completion of construction at NBPL, but would apply for a sixth IHA if
construction is not completed under this IHA.
Methods, Pile Installation--Vibratory hammers, which can be used to
either install or extract a pile, contain a system of counter-rotating
eccentric weights powered by hydraulic motors and are designed in such
a way that horizontal vibrations cancel out, while vertical vibrations
are transmitted into the pile. The pile driving machine is lifted and
positioned over the pile by means of an excavator or crane, and is
fastened to the pile by a clamp and/or bolts. The vibrations produced
cause liquefaction
[[Page 36363]]
of the substrate surrounding the pile, enabling the pile to be
extracted or driven into the ground using the weight of the pile plus
the hammer. Impact hammers use a rising and falling piston to
repeatedly strike a pile and drive it into the ground.
Non-steel piles are typically impact-driven for their entire
embedment depth, in part because non-steel piles are often displacement
piles (as opposed to pipe piles) and require some impact to allow
substrate penetration. However, jetting may be used to advance
displacement piles to a certain embedment depth. Pile jetting utilizes
a directed flow of pressurized water to assist in pile placement. The
jetting technique liquefies the soils at the pile tip during pile
placement, reducing the friction between adjacent sub-grade soil
particles around the water jet. This greatly decreases the bearing
capacity of the soils below the pile tip, causing the pile to descend
toward its final tip elevation with much less soil resistance, largely
under its own weight.
Methods, Pile Removal--There are multiple methods for pile removal.
During previous demolition, piles were generally removed by cutting at
the mudline, which can be accomplished in various ways. Piles are
expected to be removed during this fifth-year IHA primarily using a
pile cutter, which is a bladed hydraulic device that shears the pile
off. The preferred method of removing the caisson elements is to cut
them at the mudline and then into two sections using a diamond wire
cutting saw. Existing caisson elements would be removed with a
clamshell, which is a dredging bucket consisting of two similar halves
that open/close at the bottom and are hinged at the top. The clamshell
would be used to grasp and lift large components.
Piles may also be removed by simply dry pulling, or pulling after
the pile has been loosened using a vibratory hammer or a pneumatic
chipper. Jetting may be another option to loosen piles that could not
be removed through the previous procedures. Pile removal is not
generally expected to require the use of vibratory extraction or
pneumatic chipping, and these methods are considered as contingency in
the event other methods of extraction are not successful.
Construction--Construction work during the proposed fifth year of
activity would include driving of concrete piles to restore dock access
at NMAWC following Navy Marine Mammal Program (MMP) removal from NMAWC.
This work is expected to require a total of 25 days.
Demolition--Demolition of the old pier will be completed now that
the new pier is operational. Much of the demolition work will be above-
water, involving removal of the pier, pilings, plastic camels and
fenders, but in-water structure removal will also occur, as described
above under Methods, Pile Removal. The in-water portion of demolition
work planned during the period of this proposed IHA is expected to
require 156 days in total.
NMAWC--As described above, the Navy also plans to return the MMP to
its permanent location near the fuel pier, requiring extraction and
installation of concrete piles to return the NMAWC site to its original
condition. This work is expected to require 15 days.
Description of Work Accomplished
During the first in-water work season (2013-14), two primary
activities were conducted: Relocation of the MMP and the Indicator Pile
Program (IPP). During the second in-water work season (2014-15), the
IPP was concluded and simultaneous construction of the new pier and
demolition of the old pier begun. Production pile driving continued
during the third in-water work season (2015-16). During the fourth in-
water work season (2016-17) pile driving of fender piles and structural
piles for the mooring dolphins for the new fuel pier was conducted,
including two IPP piles, demolition of the old fuel pier, and pile
driving and extraction at NMAWC.
The Navy MMP, administered by Space and Naval Warfare Systems
(SPAWAR) Command Systems Center (SSC), was moved approximately three
kilometers to the NMAWC (see Figures 1-1 and 1-2 of the Navy's Year 1
monitoring report). Although not subject to the MMPA, SSC's working
animals were temporarily relocated so that they will not be affected by
the project. Over the course of 25 in-water construction days from
January 28 to March 13, 2014, the Navy removed thirty and installed 81
concrete piles (12- and 16-in). See Table 3-2 of the Navy's Year 1
monitoring report for details. Installation was accomplished via a D19-
42 American Pile Driving Equipment, Inc. (APE) diesel hammer with
energy capacity of 23,566-42,800 ft-lbs and fitted with a hydraulic
tripping cylinder with four adjustable power settings that could be
reset while driving. Pile removal was accomplished by jetting and dead
pull.
The IPP was designed to validate the length of pile required and
the method of installation (vibratory and impact) as well as to
validate acoustic sound pressure levels of the various sizes and
locations (i.e., shallow versus deeper water) of installed piles. Nine
steel pipe test piles were vibratory- and impact-driven over ten work
days from April 28 to May 15, 2014, including two 30-in and seven 36-in
piles. All piles were initially installed using an APE Variable Moment
250 VM Vibratory Hammer Extractor powered by a model 765 hydraulic
power source creating a maximum driving force of 2,389 kilonewtons (269
tons). Impact pile driving equipment consisted of a single acting
diesel impact hammer model D62-22 DELMAG with energy capacity of
76,899-153,799 ft-lbs and fitted with a hydraulic tripping cylinder
with four adjustable power settings that could be reset while driving.
One additional 36-in pile was installed in Spring 2015, under the Year
2 IHA, to conclude the IPP.
Production pile driving associated with construction of the new
pier was begun in Fall 2014 and continued into Spring 2015. Both
vibratory and impact driving was used, as described above, to install
238 steel pipe piles (four 18-in, 31 30-in, and 203 36-in diameter).
Hammers used were the same as those described above. Demolition
activity began in Spring 2015, and included the removal of four
caissons, eighteen concrete fender piles, and a portion of concrete
decking from the existing fuel pier. In total, this work consisted of
100 days of activity from October 16, 2014, through April 29, 2015. Of
these 100 days of in-water work, 18 days involved only impact driving,
15 days included only vibratory driving, and 65 days where both types
of driving occurred. The remaining two days involved only demolition
activities. Please see the Year 2 monitoring report for more
information.
Production pile driving continued in early 2016 during three
distinct construction periods from January 11 through April 30, 2016,
with 161 piles installed over the course of 50 days. Because most
structural steel pipe piles were installed under the Year 2 IHA, this
work primarily involved placement of non-structural concrete fender
piles. Both vibratory and impact driving was used, as described above,
to install 132 16-in polycarbonate coated concrete fender piles and 23
24 x 30-in concrete fender piles. In addition, six 30-in steel pipe
piles were installed as structural elements to support a mooring
dolphin. Hammers used for the steel piles were the same as those
described above. The 16-in concrete piles were driven using an APE
single action diesel impact hammer model D25-32, with energy capacity
of 29,484-58,245 ft-lbs and
[[Page 36364]]
fitted with a manual power level modulator and shut off trip. The 24 x
30-in concrete piles were driven using an APE single action diesel
impact hammer model D80-42, with energy capacity of 127,008-198,450 ft-
lbs and fitted with a manual power level modulator and shut off trip.
No demolition occurred during this period. Of the 50 days of in-water
work, 45 days involved only impact driving, two days included only
vibratory driving, and three days where both types of driving occurred.
Please see the Year 3 monitoring report for more information.
Production pile driving during Year 4 construction, from October 8,
2016 to April 30, 2017, included 68 piles of three types of piles
driven with two different methods over 34 days: 30-in steel piles were
driven with both vibratory and impact hammers, and the 24 x 30-in
concrete and 16-in poly-concrete piles were installed with impact
hammers. High pressure water jetting were used to ``pre-drill'' holes
for the 24 x 30 in piles. In addition, Structural piles were installed
for two dolphins to the south of the new fuel pier, fender piles were
installed on the east and west sides of the new fuel pier as well as on
one of the dolphins, and a single 16-inch poly-concrete pile (concrete
pile lined with a polycarbonate outer sheath) was driven on the west
side of the pier.
Demolition during Year 4 included removal of the caissons from the
north side of the old fuel pier, as well as removal of structural and
fender piles sizes under, and adjacent to, the south and north sections
of the old pier. Eighteen 84-in caissons were cut using a wire saw. A
total of 278 piles were clipped, including 14-in, 18-in, and 24-in
fender piles and 13-in polycarbonate and poly-concrete piles. Of the 69
days of in-water work, 42 days involved pile clipping and 27 days
involved pile cutting. Please see the Year 4 monitoring report for more
information.
Additional work may be conducted under the existing IHA between
September 15 and October 7, 2017, in which case the submitted
monitoring report would be amended as necessary.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of the Specified Activity
Species with the expected potential to be present during all or a
portion of the in-water work window include the California sea lion
(Zalophus californianus), harbor seal (Phoca vitulina richardii),
northern elephant seal (Mirounga angustirostris), gray whale
(Eschrichtius robustus), bottlenose dolphin (Tursiops truncatus
truncatus), Pacific white-sided dolphin (Lagenorhynchus obliquidens),
Risso's dolphin (Grampus griseus), and either short-beaked or long-
beaked common dolphins (Delphinus spp.). California sea lions are
present year-round and are very common in the project area, while
bottlenose dolphins and harbor seals are common and likely to be
present year-round but with more variable occurrence in San Diego Bay.
Gray whales may be observed in San Diego Bay sporadically during
migration periods. The remaining species are known to occur in
nearshore waters outside San Diego Bay, but are generally only rarely
observed near or in the bay. However, recent observations indicate that
these species may occur in the project area and therefore could
potentially be subject to incidental harassment from the aforementioned
activities.
There are four marine mammal species which are either resident or
have known seasonal occurrence in the vicinity of San Diego Bay,
including the California sea lion, harbor seal, bottlenose dolphin, and
gray whale (see Figures 3-1 through 3-4 and 4-1 in the Navy's
application). In addition, common dolphins (see Figure 3-4 in the
Navy's application), the Pacific white-sided dolphin, Risso's dolphin,
and northern elephant seals are known to occur in deeper waters in the
vicinity of San Diego Bay and/or have been observed within the bay
during the course of this project's monitoring. Although the latter
three species of cetacean would not generally be expected to occur
within the project area, the potential for changes in occurrence
patterns in conjunction with recent observations leads us to believe
that authorization of incidental take is warranted. Common dolphins
have been documented regularly at the Navy's nearby Silver Strand
Training Complex, and were observed in the project area during previous
years of project activity. The Pacific white-sided dolphin has been
sighted along a previously used transect on the opposite side of the
Point Loma peninsula (Merkel and Associates, 2008) and there were
several observations of Pacific white-sided dolphins during Year 2
monitoring. Risso's dolphin is fairly common in southern California
coastal waters (e.g., Campbell et al., 2010), and could occur in the
bay. Northern elephant seals are included based on their continuing
increase in numbers along the Pacific coast (Carretta et al., 2016) and
the likelihood that animals that reproduce on the islands offshore of
Baja California and mainland Mexico--where the population is also
increasing--could move through the project area during migration, as
well as the observation of a juvenile seal near the fuel pier in April
2015.
Note that common dolphins could be either short-beaked (Delphinus
delphis delphis) or long-beaked (D. delphis bairdii) subspecies. While
it is likely that common dolphins observed in the project area would be
long-beaked, as it is the most frequently stranded species in the area
from San Diego Bay to the U.S.-Mexico border (Danil and St. Leger
2011), the species distributions overlap and it is unlikely that
observers would be able to differentiate them in the field. Therefore,
we consider that any common dolphins observed--and any incidental take
of common dolphins--could be either long- or short-beaked common
dolphins.
In addition, other species that occur in the Southern California
Bight may have the potential for isolated occurrence within San Diego
Bay or just offshore. In particular, a short-finned pilot whale
(Globicephala macrorhynchus) was observed off Ballast Point, and a
Steller sea lion (Eumetopias jubatus monteriensis) was seen in the
project area during Year 2. These species are not typically observed
near the project area and, unlike the previously mentioned species, we
do not believe it likely that they will occur in the future. Given the
unlikelihood of their exposure to sound generated from the project,
these species are not considered further.
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS's Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical
and behavioral descriptions) may be found on NMFS's Web site
(www.nmfs.noaa.gov/pr/species/mammals/).
Table 2 lists all marine mammal species with expected potential for
occurrence in the vicinity of NBPL during the project timeframe and
summarizes key information, including regulatory status under the MMPA
and ESA and potential biological removal (PBR), where known. See also
Figures 3-1 through 3-5 of the Navy's application for observed
occurrence of
[[Page 36365]]
marine mammals in the project area. For taxonomy, we follow Committee
on Taxonomy (2016). 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 U.S. 2016 stock assessment report (SARs) (e.g., NMFS 2016). All
values presented in Table 2 are the most recent available at the time
of publication and are available in the 2016 SAR (available online at
www.nmfs.noaa.gov/pr/sars).
Table 2--Marine Mammals Potentially Present in the Vicinity of NBPL
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Stock abundance (CV, Relative occurrence in
Species Stock ESA/MMPA status; Nmin, most recent PBR \3\ Annual M/ San Diego Bay; season
strategic (Y/N) \1\ abundance survey) \2\ SI \4\ of occurrence
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae
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Gray whale......................... Eastern North Pacific. -; N 20,990 (0.05; 20,125; 624 132 Occasional migratory
2011). visitor; winter.
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin................. California coastal.... -; N 453 (0.06; 346; 2011). 2.7 >=2.0 Common; year-round.
Short-beaked common dolphin........ California/Oregon/ -; N 969,861 (0.17; 8,393 >=40 Occasional; year-round
Washington. 839,325; 2014). (but more common in
warm season).
Long-beaked common dolphin......... California............ -; N 101,305 (0.49; 68,432; 657 >=35.4 Occasional; year-round
2014). (but more common in
warm season).
Pacific white-sided dolphin........ California/Oregon/ -; N 26,814 (0.28; 21,195; 191 7.5 Uncommon; year-round.
Washington. 2014).
Risso's dolphin.................... California/Oregon/ -; N 6,336 (0.32; 4,817; 46 >=3.7 Rare; year-round (but
Washington. 2014). more common in cool
season).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion................ U.S................... -; N 296,750 (n/a; 153,337; 9,200 389 Abundant; year-round.
2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal........................ California............ -; N 30,968 (n/a; 27,348; 1,641 43 Common; year-round.
2012).
Northern elephant seal............. California breeding... -; N 179,000 (n/a; 81,368; 4,882 8.8 Rare; year-round.
2010).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 (see footnote 3) 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\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks of
pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction factor derived from knowledge
of the species (or similar species) life history to arrive at a best abundance estimate; therefore, there is no associated CV. In these cases, the
minimum abundance may represent actual counts of all animals ashore.
\3\ Potential biological removal, 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 size (OSP).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value.
All species that could potentially occur in the proposed survey
areas are included in Table 2. As described below, all eight species
(with nine managed stocks) temporally and spatially co-occur with the
activity to the degree that take is reasonably likely to occur, and we
have proposed authorizing it.
[[Page 36366]]
Gray Whale
Two populations of gray whales are recognized, Eastern and Western
North Pacific (ENP and WNP). The two populations have historically been
considered geographically isolated from each other; however, recent
data from satellite-tracked whales indicates that there is some overlap
between the stocks. Two WNP whales were tracked from Russian foraging
areas along the Pacific rim to Baja California (Mate et al., 2011),
and, in one case where the satellite tag remained attached to the whale
for a longer period, a WNP whale was tracked from Russia to Mexico and
back again (IWC, 2012). Between 22-24 WNP whales are known to have
occurred in the eastern Pacific through comparisons of ENP and WNP
photo-identification catalogs (IWC 2012; Weller et al., 2011; Burdin et
al., 2011), and WNP animals comprised 8.1 percent of gray whales
identified during a recent field season off of Vancouver Island (Weller
et al., 2012). In addition, two genetic matches of WNP whales have been
recorded off of Santa Barbara, CA (Lang et al., 2011). More recently,
Urban et al. (2013) compared catalogs of photo-identified individuals
from Mexico with photographs of whales off Russia and reported a total
of 21 matches. Therefore, a portion of the WNP population is assumed to
migrate, at least in some years, to the eastern Pacific during the
winter breeding season.
However, only ENP whales are expected to occur in the project area.
The likelihood of any gray whale being exposed to project sound to the
degree considered in this document is already low, as it would require
a migrating whale to linger for an extended period of time, or for
multiple migrating whales to linger for shorter periods of time. While
such an occurrence is not unknown, it is uncommon. Further, of the
approximately 20,000 gray whales migrating through the Southern
California Bight, it is extremely unlikely that one found in San Diego
Bay would be one of the approximately twenty WNP whales that have been
documented in the eastern Pacific (less than one percent probability).
The likelihood that a WNP whale would be exposed to elevated levels of
sound from the specified activities is insignificant and discountable
and WNP whales are not considered further in this document.
Gray whale transitory occurrence inside San Diego Bay is sporadic
and unpredictable. A mean group size of 2.9 gray whales was reported
for both coastal (16 groups) and non-coastal (15 groups) areas around
Southern California Bight. The largest group reported was nine animals.
The largest group reported by U.S. Navy (in 1998) was 27 animals
(Carretta et al., 2000). Gray whales are not expected in the project
area except during the northward migration, when they are closest to
the coast (Rice et al., 1981).
Bottlenose Dolphin
The California coastal stock of bottlenose dolphin is distinct from
the offshore population and is resident in the immediate (within 1 km
of shore) coastal waters, occurring primarily between Point Conception,
California, and San Quintin, Mexico. Occasionally, during warm-water
incursions such as during the 1982-1983 El Ni[ntilde]o events, their
range extends as far north as San Francisco Bay (Carretta et al.,
2017). They are commonly found in groups of 2 to 15 individuals and in
larger groups offshore.
Coastal bottlenose dolphins have occurred sporadically and in
highly variable numbers and locations in San Diego Bay. Navy surveys
showed that bottlenose dolphins were most commonly sighted in April,
and there were more dolphins observed during El Ni[ntilde]o years.
Pacific White-Sided Dolphin
Pacific white-sided dolphins are endemic to temperate waters of the
North Pacific Ocean, and are common both on the high seas and along the
continental margins (Carretta et al., 2014). Off the U.S. west coast,
Pacific white-sided dolphins occur primarily in shelf and slope waters.
Sighting patterns from aerial and shipboard surveys conducted in
California, Oregon and Washington suggest seasonal north-south
movements, with animals found primarily off California during the
colder water months and shifting northward into Oregon and Washington
as water temperatures increase in late spring and summer (Carretta et
al., 2014).
Pacific white-sided dolphins are uncommon in San Diego Bay, but
observations of this species increased during El Ni[ntilde]o years.
Monitoring during the Year 2 IHA documented 7 sightings of Pacific
white-sided dolphins, comprising 27 individuals, with a mean group size
of 3.85 individuals per sighting and an average of 0.28 individuals
sighted per day of monitoring.
Common Dolphin
Short-beaked common dolphins are the most abundant cetacean off
California and are widely distributed between the coast and at least
300 nmi offshore. In contrast, long-beaked common dolphins generally
occur within 50 nmi of shore. Both species of common dolphin appear to
shift their distributions seasonally and annually in response to
oceanographic conditions and prey availability (Carretta et al., 2016).
The long-beaked species apparently prefers shallower, warmer water than
the short-beaked common dolphin (Perrin 2009). Both tend to be more
abundant in coastal waters during warm-water months (Bearzi 2005).
The occurrence of common dolphins inside San Diego Bay is uncommon
(NAVFAC SW and POSD 2013). Small groups were observed briefly on
several occasions in the northern part of the bay by Navy monitors
during the IPP (May 2014). The animals were moving swiftly and could
not be distinguished as to species, but the weight of evidence based on
distributions of the two species and previous sightings of the long-
beaked species near San Diego is that they were probably long-beaked
common dolphins.
California Sea Lion
The entire population of California sea lions cannot be counted
because all age and sex classes are never ashore at the same time. In
lieu of counting all sea lions, pups are counted when all are ashore,
in July during the breeding season, and the number of births is
estimated from pup counts (Carretta et al., 2016). The size of the
population is then estimated from the number of births and the
proportion of pups in the population. Based on these censuses, the U.S.
stock has generally increased from the early 1900s, to a current
estimate of 296,750 (Carretta et al., 2016). There are indications that
the California sea lion may have reached or is approaching carrying
capacity, although more data are needed to confirm that leveling in
growth persists (Carretta et al., 2016).
The California sea lion is by far the most commonly-sighted
pinniped species at sea or on land in the vicinity of NBPL and northern
San Diego Bay. The Navy has conducted numerous marine mammal surveys
overlapping the north San Diego Bay project area and the potential ZOI
for impact and vibratory pile driving operations. California sea lions
regularly occur on rocks, buoys and other structures, and especially on
bait barges, although numbers vary greatly.
Harbor Seal
Harbor seals are considered abundant throughout most of their range
from Baja California to the eastern Aleutian
[[Page 36367]]
Islands. Peak numbers of harbor seals haul-out on land during late May
to early June, which coincides with the peak of their molt. Harbor
seals do not make extensive pelagic migrations, but do travel hundreds
of km on occasion to find food or suitable breeding areas (Carretta et
al., 2016). Based on likely foraging strategies, Grigg et al. (2009)
reported seasonal shifts in harbor seal movements based on prey
availability. In relationship to the entire California stock, harbor
seals do not have a significant mainland California distribution south
of Point Mugu.
Harbor seals are relatively uncommon within San Diego Bay.
Sightings in the Navy transect surveys of northern San Diego Bay
through March 2012, and were limited to individuals outside of the ZOI,
on the south side of Ballast Point (TDI 2012b; Jenkins 2012). However,
Navy marine mammal monitoring for another project conducted
intermittently at Pier 122 from 2010-2014 documented from zero to 4
harbor seals near Pier 122 (within the ZOI) at various times, with the
greatest number of sightings during April and May (Jenkins 2012; Bowman
2014). An individual harbor seal was also frequently sighted near NMAWC
during 2014 (McConchie 2014).
Northern Elephant Seal
A complete population count of elephant seals is not possible
because all age classes are not ashore simultaneously. The population
is estimated to have grown at 3.8% annually since 1988 (Lowry et al.,
2014). Northern elephant seals breed and give birth in California
(U.S.) and Baja California (Mexico), primarily on offshore islands.
Populations of northern elephant seals in the U.S. and Mexico have
recovered after being reduced to near extinction by hunting, undergoing
a severe population bottleneck and loss of genetic diversity with the
population reduced to only an estimated 10-30 individuals.
Northern elephant seals occur in the southern California bight, and
have the potential to occur in San Diego Bay (NAVFAC SW and POSD 2013),
but the only recent documentation of occurrence was of a single
distressed juvenile observed on the beach south and inshore of the Fuel
Pier during the second year IHA. Given the continuing, long-term
increase in the population of northern elephant seals (Lowry et al.,
2014), there is an increasing possibility of occurrence in the project
area.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Current data indicate that not all marine
mammal species have equal hearing capabilities (e.g., Richardson et
al., 1995; Wartzok and Ketten 1999; Au and Hastings 2008). To reflect
this, Southall et al. (2007) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. Note that no direct measurements
of hearing ability have been successfully completed for mysticetes
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65
decibel (dB) threshold from the normalized composite audiograms, with
the exception for lower limits for low-frequency cetaceans where the
lower bound was deemed to be biologically implausible and the lower
bound from Southall et al. (2007) retained. The functional groups and
the associated frequencies are indicated below (note that these
frequency ranges correspond to the range for the composite group, with
the entire range not necessarily reflecting the capabilities of every
species within that group):
Low-frequency cetaceans (mysticetes): Generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz, with best
hearing estimated to be from 100 Hz to 8 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz, with best hearing from 10 to
less than 100 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): Generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz.
Pinnipeds in water; Phocidae (true seals): Generalized
hearing is estimated to occur between approximately 50 hertz (Hz) to 86
kilohertz (kHz), with best hearing between 1-50 kHz;
Pinnipeds in water; Otariidae (eared seals): Generalized
hearing is estimated to occur between 60 Hz and 39 kHz, with best
hearing between 2-48 kHz.
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2016) for a review of available information.
Nine marine mammal species (six cetacean and three pinniped (1 otariid
and 2 phocid species)) have the reasonable potential to co-occur with
the proposed survey activities. Please refer to Table 2. Of the
cetacean species that may be present, one is classified as low-
frequency cetaceans (i.e., all mysticete species), and five are
classified as mid-frequency cetaceans (i.e., all delphinid and ziphiid
species and the sperm whale).
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The Estimated Take by Incidental Harassment section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
Negligible Impact Analysis and Determination section considers the
content of this section, the Estimated Take by Incidental Harassment
section, and the Proposed Mitigation section, to draw conclusions
regarding the likely impacts of these activities on the reproductive
success or survivorship of individuals and how those impacts on
individuals are likely to impact marine mammal species or stocks.
We provided discussion of the potential effects of the specified
activity on marine mammals and their habitat in our Federal Register
notices of proposed authorization associated with the first- and
second-year IHAs (78 FR 30873; May 23, 2013 and 79 FR 53026; September
5, 2014). The specified activity associated with this proposed IHA is
substantially similar to those considered for the first- and second-
year IHAs and the potential effects of the specified activity are the
same as those identified in those documents. Therefore, we do not
reprint the
[[Page 36368]]
information here but refer the reader to those documents.
In the aforementioned Federal Register notices, we also provided
general background information on sound and marine mammal hearing and a
description of sound sources and ambient sound and refer the reader to
those documents. However, because certain terms are used frequently in
this document, we provide brief definitions of relevant acoustic
terminology below:
Sound pressure level (SPL): Sound pressure is the force
per unit area, usually expressed in microPascals ([mu]Pa), where one
Pascal equals one Newton exerted over an area of one square meter. The
SPL is expressed in dB as twenty times the logarithm to the base ten of
the ratio between the pressure exerted by the sound to a referenced
sound pressure. SPL is the quantity that is directly measured by a
sound level meter. For underwater sound, SPL in dB is referenced to one
microPascal (re 1 [mu]Pa), unless otherwise stated. For airborne sound,
SPL in dB is referenced to 20 microPascals (re 20 [mu]Pa), unless
otherwise stated.
Frequency: Frequency is expressed in terms of
oscillations, or cycles, per second. Cycles per second are commonly
referred to as Hz. Typical human hearing ranges from 20 Hz to 20 kHz.
Peak sound pressure: The instantaneous maximum of the
absolute positive or negative pressure over the frequency range from 20
Hz to 20 kHz and presented in dB.
Root mean square (rms) SPL: For impact pile driving,
overall dB rms levels are characterized by integrating sound for each
waveform across ninety percent of the acoustic energy in each wave and
averaging all waves in the pile driving event. This value is referred
to as the rms 90 percent. With this method, the time averaging per
pulse varies.
Sound Exposure Level (SEL): A measure of energy,
specifically the dB level of the time integral of the squared-
instantaneous sound pressure, normalized to a one second period. It is
a useful metric for assessing cumulative exposure because it enables
sounds of differing duration, to be compared in terms of total energy.
The accumulated SEL (SELcum) is used to describe the SEL
from multiple events (e.g., many pile strikes). This can be calculated
directly as a logarithmic sum of the individual single-strike SELs for
the pile strikes that were used to install the pile.
Level Z weighted (unweighted), equivalent (LZeq):
LZeq is a value recorded by the SLM that represents SEL SPL
over a specified time period or interval. The LZeq is most typically
referred to in one-second intervals or over an entire event.
Level Z weighted (unweighted), fast (LZFmax):
LZFmax is a value recorded by the SLM that represents the
maximum rms value recorded for any 125 millisecond time frame during
each individual recording.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of whether the number of takes is ``small'' and the
negligible impact determination. Harassment is the only type of take
expected to result from these activities. Except with respect to
certain activities not pertinent here, section 3(18) of the MMPA
defines ``harassment'' as: Any act of pursuit, torment, or annoyance
which (i) has the potential to injure a marine mammal or marine mammal
stock in the wild (Level A harassment); or (ii) has the potential to
disturb a marine mammal or marine mammal stock in the wild by causing
disruption of behavioral patterns, including, but not limited to,
migration, breathing, nursing, breeding, feeding, or sheltering (Level
B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns for individual marine mammals
resulting from exposure to acoustic sources. Based on the nature of the
activity and the anticipated effectiveness of the mitigation measures
(i.e., shutdown, soft start, etc.--discussed in detail below in
Proposed Mitigation section), Level A harassment is neither anticipated
nor proposed to be authorized.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Described in the most basic way, 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. Below, we describe these
components in more detail and present the proposed 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 can be difficult to predict (Southall et al., 2007). 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, drilling) and above 160 dB
re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., impact pile
driving) or intermittent (e.g., scientific sonar) sources.
The Navy's proposed activity includes the use of continuous
(vibratory pile driving, demolition) and impulsive (impact pile
driving) sources, and therefore the 120 and 160 dB re 1 [mu]Pa (rms)
are applicable.
Level A harassment for non-explosive sources--NMFS's Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (NOAA 2016) 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 Navy's
construction project includes the use of impulsive (impact pile
driving) and non-impulsive (vibratory pile driving) sources.
These thresholds were developed by compiling and synthesizing the
best available science and soliciting input multiple times from both
the public and peer reviewers to inform the final product, and are
provided in the table below. The references, analysis, and methodology
used in the development of the thresholds are described in NMFS 2016
Technical Guidance, which may be accessed at: http://
[[Page 36369]]
www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
------------------------------------------------------------------------
PTS onset acoustic thresholds *
(received level)
Hearing Group -----------------------------------------
Impulsive Non-impulsive
------------------------------------------------------------------------
Low-frequency cetaceans....... Cell 1: Lpk,flat: 219 Cell 2:
dB; LE,LF,24h: 183 dB. LE,LF,24h: 199
dB.
Mid-frequency cetaceans....... Cell 3: Lpk,flat: 230 Cell 4:
dB; LE,MF,24h: 185 dB. LE,MF,24h: 198
dB.
High-frequency cetaceans...... Cell 5: Lpk,flat: 202 Cell 6:
dB; LE,HF,24h: 155 dB. LE,HF,24h: 173
dB.
Phocid Pinnipeds (underwaters) Cell 7: Lpk,flat: 218 Cell 8:
dB; LE,PW,24h: 185 dB. LE,PW,24h: 201
dB.
Otariid Pinnipeds (underwater) Cell 9: Lpk,flat: 232 Cell 10:
dB; LE,OW,24h: 203 dB. LE,OW,24h: 219
dB.
------------------------------------------------------------------------
NMFS 2016.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds.
The intensity of pile driving or sounds is greatly influenced by
factors such as the type of piles, hammers, and the physical
environment in which the activity takes place. For the installation of
30-in steel piles and pile cutting activities, acoustic monitoring
during the first and second IHA periods (NAVFAC 2015) resulted in
empirical data that are directly applicable to the fifth IHA period in
terms of the activities and the location, depth, sizes and types of
piles.
Table 4 identifies the sound source levels that are used in
evaluating impact and vibratory pile driving and extraction in the
current IHA application. Sound levels for the hydraulic pile cutter,
diamond saw caisson cutting, and pile jetting were measured during the
fourth IHA period (NAVFAC SW 2017). No acoustic data are available from
the vibratory driving of 16-in concrete piles, so the data for
vibratory installation of 30-in steel piles from the second IHA period
are used as a conservative proxy (NAVFAC SW 2015). Finally, SPLs were
measured for the impact driving of 16-in poly-concrete piles during the
third IHA monitoring period (NAVFAC SW 2016a), and are used in this
application for the same activities.
Table 4--Underwater Sound Pressure Levels From Similar In Situ Monitored Construction Activities From Previous
Years
----------------------------------------------------------------------------------------------------------------
Measured sound pressure
levels (rms) at 10 m
Project and location Pile size and type Method Water depth (dB re 1 [mu]Pa)
-------------------------
Mean \1\ Max \2\
----------------------------------------------------------------------------------------------------------------
NBPL Fuel Pier, San Diego, CA... 13 to 24-in Hydraulic pile 9 m (30 ft) 145 165.3
concrete. cutting.
NBPL Fuel Pier, San Diego, CA... 66- and 84-in steel Diamond saw 9 m (30 ft) 149 155.6
caisson. cutting.
NBPL Fuel Pier, San Diego, CA... 24-in concrete..... Jetting........... 9 m (30 ft) 155 159.9
NBPL Fuel Pier, San Diego, CA... 30-in Steel Pipe... Vibratory......... 9 m (30 ft) 162.5 \3\ 162.5
NBPL Fuel Pier, San Diego, CA... 16-in Poly-Concrete Impact............ 9 m (30 ft) 188.9 \4\ 195
----------------------------------------------------------------------------------------------------------------
\1\ Mean source levels used from data from previous monitoring reports (NAVFAC SW 2015, 2016a, 2017). Mean
source levels were used to calculate Level B ZOIs.
\2\ Maximum source levels used from data from previous monitoring reports (NAVFAC SW 2015, 2016a, 2017). Max
source levels were used to calculate Level A ZOIs. Maximum source levels used were proposed by the Navy.
\3\ Mean source levels for 30-in steel pipe piles were used as a proxy to calculate ZOIs for vibratory driving
of 16-in concrete guide piles (NAVFAC SW 2015).
\4\ The maximum source level is included for reference only. The distance to the Level B ZOI is based on in situ
data collected for 16-in poly-concrete piles and was documented in NAVFAC SW (2016a).
Scarce data exists on airborne and underwater noise levels
associated with vibratory hammer extraction. However, it can reasonably
be assumed that vibratory extraction emits SPLs that are no higher than
SPLs caused by vibratory hammering of the same materials, and results
in lower SPLs than caused by impact hammering comparable piles. For
this application, the same value (162.5 dB re 1[mu]Pa) that was
obtained for vibratory hammering of the 30-in steel piles at the Fuel
Pier (NAVFAC SW 2015) is used for the vibratory hammering of 16-in
round concrete piles at NMAWC. None of the peak SPLs for the various
sound sources reach the injury thresholds identified in the new NMFS
(2016) Technical Guidance; therefore, injury from peak sound levels is
not considered further.
Table 6 provides the calculated areas of Level A and Level B ZOIs
associated with the impulsive and continuous sounds that are
anticipated during the fifth-year IHA period. Table 5 provides the data
that were used to calculate the distances to the Level A and B ZOIs
presented in Table 6. It should be noted that the ZOI for Level A
harassment would be closely monitored and subject to shutdowns if a
marine mammal enters the area. The ZOI areas and maximum distances for
the activities at the fuel pier and NMAWC are shown in Figures 6-1 and
6-2, respectively of the Navy's application. The figures reflect the
conventional assumption that the natural or manmade shoreline acts as a
barrier to underwater sound. It is generally accepted practice to model
underwater sound propagation from pile driving as continuing in a
straight line past a shoreline projection such as Ballast Point (Dahl
2012). Similarly, it is reasonable to assume that project sound would
not propagate east of Zuniga Jetty (Dahl 2012).
[[Page 36370]]
All of the ZOIs for potential Level A acoustic harassment (Table 6)
would be buffered and encompassed by a larger shutdown zone. For
example, the ZOIs for potential Level A acoustic harassment to
pinnipeds from impact pile driving (Table 6) would be contained within
a 60 m (196 ft) shutdown zone. For impact pile driving at NMAWC, two
methods identified in NMFS (2016) were evaluated to determine the most
conservative distances to the Level A ZOIs using: (1) rms SPL source
levels; and (2) single strike equivalent SEL. The calculations showed
that the first method was the most conservative and this method was
subsequently used to determine the distances to the Level A ZOIs (Table
5). In all Level A ZOI calculations, the default values for the
weighting factor adjustment and practical spreading for propagation
loss were used (see Appendix A of the Navy's application).
Table 5--Data Used To Calculate Distances to Level B ZOIs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Activity Impact pile driving Vibratory pile driving Pile jetting Caisson cutting Pile clipping
--------------------------------------------------------------------------------------------------------------------------------------------------------
References for Source Level and Year 3 report #1 Year 2 report (NAVFAC Year 4 report (NAVFAC Year 3 report #1 Year 4 report (NAVFAC
Duration. (NAVFAC SW 2016a). SW 2015). SW 2017). (NAVFAC SW 2016a). SW 2017).
Size & Type of Piles used for 16-in poly-concrete 30-in steel piles..... 24x30-in concrete 84-in caissons....... 24-in concrete piles.
Source Data. piles. piles.
Source Level (rms SPL)............. 188.9................. 162.5................. 159.9................ 155.6................ 165.3.
Distance to Level B ZOI (m)........ 270................... 1,848................. 1,165................ 631.................. 2,511.
--------------------------------------------------------------------------------------------------------------------------------------------------------
The Level B ZOIs and distances are based on the validated SPLs
directly measured during the IHA monitoring (NAVFAC SW 2014-2017), as
available. For example, the distance to the Level B ZOI for impact
driving of 16-in poly-concrete piles was 270 m (886 ft) during Year 3
monitoring (NAVFAC SW 2016a). In cases where monitoring data are not
available to empirically measure the extent of the Level B ZOI
(activities at NMAWC), ``practical spreading loss'' from the source at
10 m has been assumed (15 log[distance/10]) and used to calculate the
maximum extent of the ZOI based on the applicable threshold. Computed
distances to the threshold for acoustic disturbance from non-impulsive
sources are based on the distances at which the project sound source
declines to ambient. Because the mean ambient sound levels in San Diego
Bay range from approximately 128 to 130 dB rms (NAVFAC SW 2015), the
120 dB acoustic threshold for the Level B ZOIs are based on an
approximate value between 128 and 129 dB. The distances for all
activities producing sound at NMAWC will be verified via hydrophone
during project activities.
Table 6--Calculated Maximum Areas of ZOIs and Distances to Relevant Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Measured/calculated distances to thresholds (m) and areas of ZOIs (m\2\ or km\2\)
--------------------------------------------------------------------------------------------------------------------------
Underwater Airborne
Activity --------------------------------------------------------------------------------------------------------------------------
Level A \1\ \2\ \3\ Level B \4\ Level B
--------------------------------------------------------------------------------------------------------------------------
LF MF PW OW 160 dB 120 dB \5\ 100 dB \6\ 90 dB \6\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Old Fuel Pier and Temporary Mooring Dolphin Demolition
--------------------------------------------------------------------------------------------------------------------------------------------------------
66-inch and 84-inch caissons 3.6 m 0.3 m 2.2 m 0.2m N/A 631 m N/A
(Diamond saw cutting). 41 m\2\ <1 m\2\ 15 m\2\ <1 m\2\ 0.7157 km\2\
Concrete piles (Pile 1.2 m 0.1 m 0.7 m 0.0 m N/A 2,511 m
clipping). 4 m\2\ <1 m\2\ < 1 m\2\ 0 m\2\ 4.4512 km\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMAWC Construction and Demolition
--------------------------------------------------------------------------------------------------------------------------------------------------------
16-inch concrete piles 8.3 m 0.7 m 5.1 m 0.4 m N/A 1,848 m 42 m 149 m
(Vibratory extraction/ 216 m\2\ <1 m\2\ 82 m\2\ <1 m\2\ 2.4473 km\2\ 5,503 m\2\ 69,646 m\2\
driving) \8\.
16-inch concrete piles 63.4 m 2.3 m 33.9 m 2.5 m 270 m N/A
(Impact driving) \9\. 0.0126 km\2\ 17 m\2\ 3,610 m\2\ 20 m\2\ 0.1408 km\2\
-----------------------------
16-inch concrete piles 3.9 m 0.3 m 2.4 m 0.2 m N/A 1,165m N/A
(Jetting pile extraction). 47.8 m\2\ <1 m\2\ 18 m\2\ <1 m\2\ 1.4268 km\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ If measured value thresholds are less than 10 m (33 ft), a minimum monitoring distance of 10 m (33 ft) would be implemented.
\2\ Based on measured mean source levels. The relevant data have been included in Appendix A of the Navy's application, which provides information from
previous years' data collected as part of the Fuel Pier Project (NAVFAC SW 2015, 2016a, 2017).
\3\ LF = Low-frequency cetaceans; MF = Mid-frequency cetaceans; PW = Phocid pinnipeds; OW = Otariid pinnipeds. The high-frequency cetacean hearing group
(HF) is omitted, because no species in the hearing group occur in, or around, the Project area.
\4\ Based on measured maximum source levels, unless otherwise stated. The relevant data have been included in Appendix A, which provides information
from previous years' data collected as part of the Fuel Pier Project (NAVFAC SW 2015, 2016a, 2017).
\5\ Average ambient sound levels in San Diego Bay are approximately 128 to 130 dB rms (NAVFAC SW 2015), and all 120 dB Level B ZOIs are based on an
approximate value between 128 and 129, which represents ambient levels in the Bay.
\6\ Airborne ZOIs based on conservative representative data (collected during 30-inch vibratory pile driving from IHA #4). Airborne noise levels did not
exceed thresholds during IHA #4 monitoring of demolition activities.
\7\ Plasma torch noise levels are not expected to exceed underwater or airborne regulatory thresholds.
\8\ Based on conservative representative source levels of 162.5 dB rms (30-inch steel vibratory pile driving, NAVFAC SW 2015).
[[Page 36371]]
Airborne Sound
Although sea lions are known to haul-out regularly on man-made
objects in the vicinity of the project site (see Figure 4-1 of the
Navy's application), and harbor seals are occasionally observed hauled
out on rocks along the shoreline in the vicinity of the project site,
none of these are within the ZOIs for airborne sound, and we believe
that incidents of take resulting solely from airborne sound are
unlikely. The zones for sea lions are within the minimum shutdown zone
defined for underwater sound and, although the zones for harbor seals
are larger, they have not been observed to haul out as readily on man-
made structure in the immediate vicinity of the project site. There is
a possibility that an animal could surface in-water, but with head out,
within one of the defined zones and thereby be exposed to levels of
airborne sound that we associate with harassment, but any such
occurrence would likely be accounted for in our estimation of
incidental take from underwater sound.
We generally recognize that pinnipeds occurring within an estimated
airborne harassment zone, whether in the water or hauled out, could be
exposed to airborne sound that may result in behavioral harassment.
However, any animal exposed to airborne sound above the behavioral
harassment threshold is likely to also be exposed to underwater sound
above relevant thresholds (which are typically in all cases larger
zones than those associated with airborne sound). Thus, the behavioral
harassment of these animals is already accounted for in these estimates
of potential take. Multiple incidents of exposure to sound above NMFS'
thresholds for behavioral harassment are not believed to result in
increased behavioral disturbance, in either nature or intensity of
disturbance reaction. Therefore, we do not believe that authorization
of incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further here. Distances
associated with airborne sound and shown in Table 5 are for reference
only.
When 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 will result in some degree of
overestimate of Level A take. However, these tools offer the best way
to predict appropriate isopleths when more sophisticated 3D modeling
methods are not available, and NMFS continues to develop ways to
quantitatively refine these tools, and will qualitatively address the
output where appropriate. For stationary sources such as vibratory pile
driving, NMFS User Spreadsheet predicts the closest distance at which,
if a marine mammal remained at that distance the whole duration of the
activity, it would not incur PTS. Inputs used in the User Spreadsheet,
and the resulting isopleths are reported below.
Table 7--Level A User Spreadsheet Input
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact pile driving Vibratory pile driving Caisson cutting Pile clipping Pile jetting
--------------------------------------------------------------------------------------------------------------------------------------------------------
References for Source Level and Year 3 report #1 Year 2 report (NAVFAC Year 3 report #1 Year 4 report (NAVFAC Year 4 report (NAVFAC
Duration. (NAVFAC SW 2016a). SW 2015). (NAVFAC SW 2016a). SW 2017). SW 2017).
Spreadsheet Tab Used............... (E.1) Impact pile (A.) Non-Impulse Stat- (A.) Non-Impulse Stat- (A.) Non-Impulse Stat- (A.) Non-Impulse Stat-
driving. Cont. Cont. Cont. Cont.
Source Level (Single Strike/shot 188.9................. 162.5................. 149.................. 145.................. 155.
SEL).
Weighting Factor Adjustment (kHz).. 2..................... 2.5................... 2.5.................. 2.5.................. 2.5.
(a) Activity Duration (h) within 24- 0.71.................. 0.95.................. 6.................... 2.82................. 1.74.
h period.
Propagation (xLogR)................ 15.................... 15.................... 15................... 15................... 15.
Distance of source level 10.................... 10.................... 10................... 10................... 10.
measurement (m).
Pulse duration (sec) \1\........... 0.03.................. n/a................... n/a.................. n/a.................. n/a.
Number of strikes in 1 h........... 193................... n/a................... n/a.................. n/a.................. n/a.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Pulse duration was measured in previous construction years and the average pulse duration was 0.03 at 10 m (NAVFAC SW 2016a).
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
For all species, the best scientific information available was
considered for use in the marine mammal take assessment calculations.
Although various regional offshore surveys for marine mammals have been
conducted, it is unlikely that these data would be representative of
the species or numbers that may be encountered in San Diego Bay.
However, the Navy has conducted a large number of ongoing site-specific
marine mammal surveys during appropriate seasons (e.g., Merkel and
Associates 2008; Johnson 2010, 2011; Lerma 2012, 2014). Whereas
analyses for the first-year IHA relied on surveys conducted from 2007-
12, continuing surveys by the Navy have generally indicated increasing
abundance of all species and the second-year IHA relied on 2012-14
survey data. In addition, the Navy has developed estimates of marine
mammal densities in waters associated with training and testing areas
(including Hawaii-Southern California) for the Navy Marine Species
Density Database (NMSDD). A technical report (Hanser et al., 2015)
describes methodologies and available information used to derive these
densities, which are based upon the best available information, except
where specific local abundance information is available and applicable
to a specific action area. The document is publicly available online
at: nwtteis.com/DocumentsandReferences/NWTTDocuments/SupportingTechnicalDocuments.aspx (accessed July 13, 2017).
Year 2 project monitoring showed even greater abundance of certain
species, and we consider all of these data in order to provide the most
up-to-date estimates for marine mammal abundances during the period of
this proposed IHA. Although Years 3 and 4 project monitoring showed
declines in marine mammal abundance in the vicinity of the project, we
retain prior density estimates as a conservative measure for estimating
exposure.
[[Page 36372]]
Density information is shown in Table 9. These data are from dedicated
line-transect surveys, required project marine mammal monitoring,
opportunistic observations for more rarely observed species (see
Figures 3-1 through 3-5 of the Navy's application), or the NMSDD.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate.
The following assumptions are made when estimating potential
incidences of take:
All marine mammal individuals potentially available are
assumed to be present within the relevant area, and thus incidentally
taken;
An individual can only be taken once during a 24-h period;
The assumed ZOIs and days of activity are as shown in
Table 5; and,
Exposures to sound levels at or above the relevant
thresholds equate to take, as defined by the MMPA.
In this case, the estimation of marine mammal takes uses the
following calculation:
Exposure estimate = n * ZOI * days of total activity
Where:
n = density estimate used for each species/season.
ZOI = sound threshold ZOI area; the area encompassed by all
locations where the SPLs equal or exceed the threshold being
evaluated.
The ZOI impact area is estimated using the relevant distances in
Table 5, assuming that sound radiates from a central point in the water
column slightly offshore of the existing pier and taking into
consideration the possible affected area due to topographical
constraints of the action area (i.e., radial distances to thresholds
are not always reached).
Table 8--Areas of Acoustic Influence and Days of Activity
------------------------------------------------------------------------
Activity Number of days ZOI (km\2\)
------------------------------------------------------------------------
66-inch and 84-inch caissons (Diamond 50 0.7157
saw cutting)...........................
Concrete piles (Pile clipping).......... 100 4.4512
16-inch concrete piles (Vibratory 25 2.4473
extraction/driving) \1\................
16-inch concrete piles (Jetting pile 15 1.4268
extraction)............................
------------------------------------------------------------------------
\1\ We assume that impact driving of 16-in concrete piles would always
occur on the same day as vibratory driving of the same piles.
Therefore, the impact driving ZOI (0.1408 km\2\) would always be
subsumed by the vibratory driving ZOI.
There are a number of reasons why estimates of potential incidents
of take may be conservative, assuming that available density and
estimated ZOI areas are accurate. We assume, in the absence of
information supporting a more refined conclusion, that the output of
the calculation represents the number of individuals that may be taken
by the specified activity. In fact, in the context of stationary
activities such as pile driving and in areas where resident animals may
be present, this number more realistically represents the number of
incidents of take that may accrue to a smaller number of individuals.
While pile driving can occur any day throughout the period of validity,
and the analysis is conducted on a per day basis, only a fraction of
that time (typically a matter of hours on any given day) is actually
spent pile driving. The potential effectiveness of mitigation measures
in reducing the number of takes is typically not quantified in the take
estimation process. For these reasons, these take estimates may be
conservative. See Table 9 for total estimated incidents of take.
California Sea Lion
During the second IHA period, an average of 90.35 California sea
lions were seen per day within the maximum ZOI for pile driving, an
area of 5.6752 km\2\ extending 3,000 m from the Fuel Pier. This equates
to a density of 15.9201/km\2\. This density is used to estimate numbers
of takes within the different ZOIs. NMFS estimates 8,971 Level B takes
for this species. The maximum extents of the potential acoustic Level A
ZOIs for cumulative exposure from all of the activities are much less
than 10 m from the source, and therefore the 60-m shutdown zone will
reduce the chance for Level A take. As a result, no Level A take of
California sea lions is anticipated nor proposed to be authorized.
Harbor Seal
Sightings of harbor seals averaged 2.83 individuals per day during
the period of the second IHA (NAVFAC SW 2015), a density of 0.4987/
km\2\ within the maximum ZOI for pile driving. This density is used to
estimate numbers of takes within the different ZOIs. NMFS estimates 281
Level B takes for this species. The maximum extent of the potential
acoustic Level A ZOI for cumulative exposure from impact pile driving
extends 34 m from the source; for all other activities, the Level A
ZOIs are much less than 10 m from the source, therefore a 60-m shutdown
zone will be in place to avoid Level A takes to harbor seals. Level A
takes are not anticipated nor proposed for authorization.
Northern Elephant Seal
Only a single individual elephant seal was sighted during the
second IHA period (NAVFAC SW 2015), but with increasing numbers
(Carretta et al., 2016), they are considered a reasonable possibility
to occur more frequently during the fifth IHA period. The regional
density estimate of 0.0760/km\2\ (Navy 2017) is assumed for the project
area. This density is used to estimate numbers of takes within the
different ZOIs. NMFS estimates 43 Level B takes for this species.
Potential takes would likely involve single individuals that are on the
shoreline or structures at the identified location, or swimming in the
vicinity, most likely near the mouth of the bay. The maximum extent of
the potential acoustic Level A ZOI for cumulative exposure from impact
pile driving extends 34 m from the source; for all other activities,
the Level A ZOIs are much less than 10 m from the source, therefore a
shutdown will be in place to avoid Level A takes to harbor seals. Level
A takes are not anticipated nor proposed for authorization.
Bottlenose Dolphin
Coastal bottlenose dolphins can occur at any time of year in
northern San Diego Bay. Numbers sighted have been highly variable but
have increased in recent years (NAVFAC SW 2014, 2015). During the
second IHA period, an average of 7.09 individuals was seen per day, a
density of 1.2493/km\2\. This density is used to estimate numbers of
takes within the different ZOIs. NMFS estimates 704 Level B takes for
this species. The maximum extents of the potential acoustic Level A
ZOIs for cumulative exposure from all of the activities are much less
than 10 m from
[[Page 36373]]
the source, and therefore the minimum 10 m shutdown will reduce the
chance for Level A take. As a result, no Level A take of bottlenose
dolphins is anticipated nor proposed to be authorized.
Common Dolphin
An average of 8.67 common dolphins was seen per day, a density of
1.5277/km\2\ within the maximum ZOI, during the second IHA period
(NAVFAC SW 2015). This density is considerably higher than the regional
density estimate for long-beaked common dolphins--the species most
likely to occur (Navy 2017), but is reasonable for the project area
given the group sizes observed for these species. Barlow (2010)
reported average group sizes in southern California of 122 for short-
beaked common dolphins and 195 for long-beaked common dolphins, and
during the second IHA period, groups of approximately 170 and 300
individuals entered the project area on different occasions (NAVFAC SW
2015). Considering the possibility for one or more large groups of
common dolphins to enter San Diego Bay during in-water activities and
the fact that the Level B ZOIs will extend completely across the bay
during pile driving, the density estimate is considered appropriate. A
density of 1.5277/km\2\ is used to estimate numbers of takes within the
different ZOIs. NMFS estimates 861 Level B takes for this species. The
maximum extents of the potential acoustic Level A ZOIs for cumulative
exposure from all of the activities are much less than 10 m from the
source, and therefore the shutdown will reduce the chance for Level A
take. As a result, no Level A take of bottlenose dolphins is
anticipated nor proposed to be authorized.
Pacific White-Sided Dolphin
Pacific white-sided dolphins are more commonly seen offshore, but
were documented in the project area on several occasions during the
second IHA period. An average of 0.28 individuals per day was seen
during the second IHA period (NAVFAC SW 2015), a density of 0.0493/
km\2\ within the maximum ZOI. This density is used to estimate numbers
of takes within the different ZOIs. NMFS estimates 28 Level B takes for
this species. The maximum extents of the potential acoustic Level A
ZOIs for cumulative exposure from all of the activities are much less
than 10 m from the source, and therefore the shutdown will reduce the
chance for Level A take. As a result, no Level A take of bottlenose
dolphins is anticipated nor proposed to be authorized.
Risso's Dolphin
While there have been no sightings of Risso's dolphin within the
project area, the species is considered a reasonable possibility for
the fifth IHA period given recent El Ni[ntilde]o conditions (Shane
1995) and its abundance in Southern California coastal waters
(Jefferson et al. 2014). The upper limit of the regional density
estimate, 0.2029/km\2\ (Navy 2017), is used to estimate numbers of
takes within the different ZOIs. NMFS estimates 114 Level B takes for
this species. The maximum extents of the potential acoustic Level A
ZOIs for cumulative exposure from all of the activities are much less
than 10 m from the source, and therefore the shutdown will reduce the
chance for Level A take. As a result, no Level A take of bottlenose
dolphins is anticipated nor proposed to be authorized.
Gray Whale
Gray whale occurrence within northern San Diego Bay is sporadic and
would likely consist of one-few individuals that venture close to, or
enter the bay for a brief period, and then continue on their migration.
A density estimate based on the rare sightings of gray whales near the
mouth of the bay during the second IHA period (NAVFAC SW 2015), would
be less than 0.01/km\2\, which is slightly less than the regional
density estimate of 0.0179/km\2\ in southern California waters during
winter-spring (Navy 2017). The regional density estimate is applied
here as a reasonable estimate given the possibility of animals moving
closer to shore and entering the mouth of the bay during the fifth IHA
period. This density is used to estimate numbers of takes within the
different ZOIs. NMFS estimates 10 Level B takes for this species. The
maximum extent of the potential acoustic Level A ZOI for cumulative
exposure from impact pile driving extends 63 m from the source; for all
other activities, the Level A ZOIs are much less than 10 m from the
source. Gray whales are not expected to occur that close to the source;
however, the Navy has proposed a minimum of 10 m (100 m for impact
driving) shutdown will be in place to avoid Level A takes to gray
whales. Level A takes are not anticipated nor proposed for
authorization.
Table 9--Calculations for Incidental Take Estimation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory
Diamond saw extraction/ Jetting pile Total proposed
Species Density cutting of 66- Pile clipping driving of 16- extraction of Total Level B authorized
inch and 84- concrete piles inch concrete 16 in concrete takes * takes (% of
inch caissons piles piles total stock)
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion..................... 15.9201 570 7086 974 341 8,971 3.023
Harbor seal............................. 0.4987 18 222 31 11 281 0.907
Northern elephant seal.................. 0.076 3 34 5 2 43 0.024
Bottlenose dolphin...................... 1.2493 45 556 76 27 704 \2\ 155
Common dolphin.......................... 1.5277 55 680 93 33 861 \3\ 0.088; \4\
0.85
Pacific white-sided dolphin............. 0.0493 2 22 3 1 28 0.104
Risso's dolphin......................... 0.2027 7 90 12 4 114 1.799
Gray whale.............................. 0.0179 1 8 1 0 10 0.048
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Due to rounding of takes to the nearest whole number of animals, (which occurs at the very end, not per activity), totals may not always equal the sum
of the takes from individual activities.
\1\ We assume that impact driving of steel piles would occur on the same day as vibratory driving of the same piles and that the zone for vibratory
driving would always subsume the zone for impact driving. Therefore, separate estimates are not provided for impact driving of steel piles.
\2\ The proposed numbers of authorized take for bottlenose dolphins are higher relative to the total stock abundance estimate and would not represent
small numbers if a significant portion of the take was for a new individual. However, these numbers represent the estimated incidents of take, not the
number of individuals taken. That is, it is likely that a relatively small subset of California coastal bottlenose dolphins would be incidentally
harassed by project activities.
\3\ SB = short-beaked common dolphin.
\4\ LB = long-beaked common dolphin.
[[Page 36374]]
Proposed 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.
The mitigation strategies described below largely follow those
required and successfully implemented under the first four IHAs
associated with this project. For this proposed IHA, data from acoustic
monitoring conducted during the first four years of work was used to
estimate zones of influence (ZOIs; see Estimated Take by Incidental
Harassment); these values were used to develop mitigation measures for
pile driving activities at NBPL. The ZOIs effectively represent the
mitigation zone that would be established around each pile to minimize
Level A harassment to marine mammals, while providing estimates of the
areas within which Level B harassment might occur. In addition, the
Navy has defined buffers to the estimated Level A harassment zones to
further reduce the potential for Level A harassment. In addition to the
measures described later in this section, the Navy would conduct
briefings between construction supervisors and crews, marine mammal
monitoring team, acoustic monitoring team, and Navy staff prior to the
start of all pile driving activity, and when new personnel join the
work, in order to explain responsibilities, communication procedures,
marine mammal monitoring protocol, and operational procedures.
Monitoring and Shutdown for Pile Driving
The following measures would apply to the Navy's mitigation through
shutdown and disturbance zones:
Shutdown Zone--For all pile driving and removal activities, the
Navy will establish a shutdown zone intended to contain the area in
which SPLs equal or exceed the calculated Level A zones (refer to
table). The purpose of a shutdown zone is to define an area within
which shutdown of activity would occur upon sighting of a marine mammal
(or in anticipation of an animal entering the defined area), thus
preventing injury of marine mammals (serious injury or death are
unlikely outcomes even in the absence of mitigation measures).
Estimated radial distances to the relevant thresholds are shown in
Table 5. For certain activities, the shutdown zone would not exist
because source levels indicate that the radial distance to the
threshold would be less than 10 m. However, a minimum shutdown zone of
10 m will be established during all pile driving and removal
activities, regardless of the estimated zone. In addition the Navy
proposes to effect a buffered shutdown zone that is intended to
significantly reduce the potential for Level A harassment given that,
in particular, California sea lions are quite abundant in the project
area and bottlenose dolphins may surface unpredictably and move
erratically in an area with a large amount of construction equipment.
These buffers are approximately double the distance to the Level A ZOI.
These zones are also shown in Table 10. These precautionary measures
are intended to prevent the already unlikely possibility of physical
interaction with construction equipment and to establish a
precautionary minimum zone with regard to acoustic effects.
Table 10--Shutdown Zones for Level A ZOIs and Monitoring Zones for Level B Zones
----------------------------------------------------------------------------------------------------------------
Monitored distances to thresholds (meters [feet])
-----------------------------------------------------------------------------
Underwater
Activity -----------------------------------------------------------------------------
Level A (shutdown) Level B
-----------------------------------------------------------------------------
LF \1\ MF \1\ PW \1\ OW \1\ 160 dB 120 dB \2\
----------------------------------------------------------------------------------------------------------------
Old Fuel Pier and Temporary Mooring Dolphin Demolition
----------------------------------------------------------------------------------------------------------------
66-inch and 84-inch caissons N/A 631
(Diamond saw cutting)............ 10
----------------------------------------------------
Concrete piles (Pile clipping).... 10 N/A 2,511
----------------------------------------------------------------------------------------------------------------
NMAWC Construction and Demolition
----------------------------------------------------------------------------------------------------------------
16-inch concrete piles (Vibratory
extraction/driving).............. 20 \4\
10 N/A 1,848
----------------------------------------------------
16-inch concrete piles (Impact
driving)......................... 100 \5\
60 \6\ 857.7 N/A
----------------------------------------------------
16-inch concrete piles (Jetting N/A 1,165
pile extraction)................. 10
-----------------------------------------------------------------------------
[[Page 36375]]
16-inch concrete piles (Pile dead-
pull)............................ 10
N/A
----------------------------------------------------------------------------------------------------------------
\1\ LF = Low-frequency cetaceans; MF = Mid-frequency cetaceans; PW = Phocid pinnipeds; OW = Otariid pinnipeds.
The high-frequency cetacean hearing group (HF) is omitted, because no species in the hearing group occur in,
or around, Project area.
\2\ Mean ambient sound levels in San Diego Bay are approximately 128 dB rms (NAVFAC SW 2015), and all 120 dB
Level B ZOIs are based on the ambient value. The distances for all activities producing sound at NMAWC will be
verified via hydrophone during project activities.
\3\ Airborne noise levels did not exceed regulatory thresholds during previous IHAs. No airborne monitoring will
take place for diamond saw cutting of caissons, plasma torch cutting of temporary mooring dolphin 30-inch
steel piles, jetting or dead-pull extraction of concrete piles.
\4\ Includes buffer of calculated Level A threshold out to 20 m (65.6 ft).
\5\ Includes buffer of calculated Level A threshold out to 100 m (328 ft).
\6\ Includes buffer of calculated Level A threshold out to 60 m (328 ft).
Disturbance Zone--Disturbance zones are the areas in which SPLs
equal or exceed 160 and 120 dB rms (for impulse and continuous sound,
respectively). Disturbance zones provide utility for monitoring
conducted for mitigation purposes (i.e., shutdown zone monitoring) by
establishing monitoring protocols for areas adjacent to the shutdown
zones. Monitoring of disturbance zones enables observers to be aware of
and communicate the presence of marine mammals in the project area but
outside the shutdown zone and thus prepare for potential shutdowns of
activity. However, the primary purpose of disturbance zone monitoring
is for documenting incidents of Level B harassment; disturbance zone
monitoring is discussed in greater detail later (see Proposed
Monitoring and Reporting). Nominal radial distances for disturbance
zones are shown in Table 10.
In order to document observed incidents of harassment, monitors
record all marine mammal observations, regardless of location. The
observer's location, as well as the location of the pile being driven,
is known from a GPS. The location of the animal is estimated as a
distance from the observer, which is then compared to the location from
the pile. If acoustic monitoring is being conducted for that pile, a
received SPL may be estimated, or the received level may be estimated
on the basis of past or subsequent acoustic monitoring. It may then be
determined whether the animal was exposed to sound levels constituting
incidental harassment in post-processing of observational and acoustic
data, and a precise accounting of observed incidences of harassment
created. Therefore, although the predicted distances to behavioral
harassment thresholds are useful for estimating incidental harassment
for purposes of authorizing levels of incidental take, actual take may
be determined in part through the use of empirical data.
Acoustic measurements will continue during the fifth year of
project activity and zones would be adjusted as indicated by empirical
data. Please see the Navy's Acoustic and Marine Species Monitoring Plan
(Monitoring Plan; available at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm) for full details.
Monitoring Protocols--Monitoring would be conducted before, during,
and 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. Observations made outside the
shutdown zone will not result in shutdown; that pile segment would be
completed without cessation, unless the animal approaches or enters the
shutdown zone, at which point all pile driving activities would be
halted. Monitoring will take place from fifteen minutes prior to
initiation through thirty minutes post-completion of pile driving
activities. Pile driving activities include the time to remove a single
pile or series of piles, as long as the time elapsed between uses of
the pile driving equipment is no more than thirty minutes. Please see
the Monitoring Plan for full details of the monitoring protocols.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable (as defined in the
Monitoring Plan) to monitor for marine mammals and implement shutdown/
delay procedures when applicable by calling for the shutdown to the
hammer operator. Qualified observers are trained biologists, with the
following minimum qualifications:
(a) Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
(b) Ability to conduct field observations and collect data
according to assigned protocols;
(c) Experience or training in the field identification of marine
mammals, including the identification of behaviors;
(d) Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
(e) 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 observed within a defined shutdown zone; and marine
mammal behavior; and
(f) 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.
(2) Prior to the start of pile driving activity, the shutdown zone
will be monitored for fifteen minutes to ensure that it is clear of
marine mammals. Pile driving will only commence once observers have
declared the shutdown zone clear of marine mammals; animals will be
allowed to remain in the shutdown zone (i.e., must leave of their own
volition) and their behavior will be monitored and documented. The
shutdown zone may only be declared
[[Page 36376]]
clear, and pile driving started, when the entire shutdown zone is
visible (i.e., when not obscured by dark, rain, fog, etc.). In
addition, if such conditions should arise during impact pile driving
that is already underway, the activity would be halted.
(3) If a marine mammal approaches or enters the shutdown zone
during the course of pile driving operations, activity will be halted
and delayed until either the animal has voluntarily left and been
visually confirmed beyond the shutdown zone or fifteen minutes have
passed without re-detection of small cetaceans or pinnipeds and 30
minutes for gray whales. Monitoring will be conducted throughout the
time required to drive a pile and for thirty minutes following the
conclusion of pile driving.
Sound Attenuation Devices
The use of bubble curtains to reduce underwater sound from impact
pile driving was considered prior to the start of the project but was
determined to not be practicable. Use of a bubble curtain in a channel
with substantial current may not be effective, as unconfined bubbles
are likely to be swept away and confined curtain systems may be
difficult to deploy effectively in high currents. Data gathered during
monitoring of construction on the San Francisco-Oakland Bay Bridge
indicated that no reduction in the overall linear sound level resulted
from use of a bubble curtain in deep water with relatively strong
current (Illingworth & Rodkin 2001). During project monitoring for pile
driving associated with the Richmond-San Rafael Bridge, also in San
Francisco Bay, it was observed that performance in moderate current was
significantly reduced (Oestman et al., 2009). Lucke et al. (2011) also
note that the effectiveness of most currently used curtain designs may
be compromised in stronger currents and greater water depths. We
believe that conditions (relatively deep water and strong tidal
currents of up to 3 knots (kn)) at the project site would disperse the
bubbles and compromise the effectiveness of sound attenuation.
Timing Restrictions
In-order to avoid impacts to least tern populations when they are
most likely to be foraging and nesting, in-water work will be
concentrated from October 1-April 1 or, depending on circumstances, to
April 30. However, this limitation is in accordance with agreements
between the Navy and FWS, and is not a requirement of this proposed
IHA. All in-water construction activities would occur only from 45
minutes after sunrise to 45 minutes before sunset.
Soft Start
The use of a soft start procedure is believed to provide additional
protection to marine mammals by warning or providing a chance to leave
the area prior to the hammer operating at full capacity, and typically
involves a requirement to initiate sound from the hammer at reduced
energy followed by a waiting period. This procedure is repeated two
additional times. It is difficult to specify the reduction in energy
for any given hammer because of variation across drivers and, for
impact hammers, the actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes.'' The project will utilize soft start techniques
for impact pile driving. We require an initial set of three strikes
from the impact hammer at reduced energy, followed by a thirty-second
waiting period, then two subsequent three strike sets. Soft start will
be required at the beginning of each day's impact pile driving work and
at any time following a cessation of impact pile driving of thirty
minutes or longer; the requirement to implement soft start for impact
driving is independent of whether vibratory driving has occurred within
the prior thirty minutes.
Based on our evaluation of the Navy's proposed measures, as well as
any other potential measures that may be relevant to the specified
activity, we have preliminarily determined that the proposed mitigation
measures provide the means of effecting the least practicable impact on
marine mammal species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an 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
incidental take 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 proposed 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 impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of an individual; or (2) Population,
species, or stock.
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.
Please see the Monitoring Plan (available at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm) for full details of the
requirements for monitoring and reporting. Notional monitoring
locations (for biological and acoustic monitoring) are shown in Figures
3-1 and 3-2 of the Plan. The purpose of this Plan is to provide
protocols for acoustic and marine mammal monitoring implemented during
pile driving and removal activities. We have preliminarily determined
this monitoring plan, which is summarized here and which largely
follows the monitoring strategies required and successfully implemented
under the previous IHAs, to be sufficient to meet the MMPA's monitoring
and reporting requirements. The previous monitoring plan was modified
to integrate adaptive changes to the monitoring methodologies as well
as updates to the scheduled construction activities. Monitoring
objectives are as follows:
Monitor in-water construction activities, including the
implementation of in-situ acoustic monitoring efforts to
[[Page 36377]]
continue to measure SPLs from in-water construction and demolition
activities not previously monitored or validated during the previous
IHAs. This would include collection of acoustic data for activities and
pile types for which sufficient data has not previously been collected,
including for diamond saw cutting of caissons and pile clipping of the
concrete piles during fuel pier demolition. The Navy also plans to
collect acoustic data for vibratory extraction and/or driving, impact
driving, jetting pile extraction and pile dead-pull of the concrete
piles at NMAWC.
Monitor marine mammal occurrence and behavior during in-
water construction activities to minimize marine mammal impacts and
effectively document marine mammals occurring within ZOI boundaries.
Collection of ambient underwater sound measurements in the absence
of project activities has been concluded, as a rigorous baseline
dataset for the project area has been developed.
Acoustic Measurements
The primary purpose of acoustic monitoring is to empirically verify
modeled injury and behavioral disturbance zones (defined at radial
distances to NMFS-specified thresholds; see Estimated Take by
Incidental Harassment). For non-pulsed sound, distances will continue
to be evaluated for attenuation to the point at which sound becomes
indistinguishable from background levels. Empirical acoustic monitoring
data will be used to document transmission loss values determined from
past measurements and to examine site-specific differences in SPL and
affected ZOIs on an as needed basis.
Should monitoring results indicate it is appropriate to do so,
marine mammal mitigation zones may be revised as necessary to encompass
actual ZOIs. Acoustic monitoring will be conducted as specified in the
approved Monitoring Plan. Please see Table 2-2 of the Plan for a list
of equipment to be used during acoustic monitoring. Monitoring
locations will be determined based on results of previous acoustic
monitoring effort and the best professional judgment of acoustic
technicians.
For activities such as demolition of the old fuel pier and
temporary mooring dolphin, the Navy will continue to collect in situ
acoustic data to validate source levels and ZOIs. Environmental data
would be collected including but not limited to: Wind speed and
direction, air temperature, humidity, surface water temperature, water
depth, wave height, weather conditions and other factors that could
contribute to influencing the airborne and underwater sound levels
(e.g., aircraft, boats). Full details of acoustic monitoring
requirements may be found in section 4.2 of the Navy's Monitoring Plan.
Visual Marine Mammal Observations
The Navy will collect sighting data and behavioral responses to
construction for marine mammal species observed in the region of
activity during the period of activity. All observers will be trained
in marine mammal identification and behaviors and are required to have
no other construction-related tasks while conducting monitoring. The
Navy will monitor the shutdown zone and disturbance zone before,
during, and after pile driving as described under Proposed Mitigation
and in the Monitoring Plan, with observers located at the best
practicable vantage points. Notional monitoring locations are shown in
Figures 3-3 and 3-4 of the Navy's Plan. Please see that plan, available
at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm, for full
details of the required marine mammal monitoring. Section 3.2 of the
Plan and Section 13 of the Navy's application offer more detail
regarding monitoring protocols. Based on our requirements, the Navy
would implement the following procedures for pile driving:
MMOs would be located at the best vantage point(s) in
order to properly see the entire shutdown zone and as much of the
disturbance zone as possible.
During all observation periods, observers will use
binoculars and the naked eye to search continuously for marine mammals.
If the shutdown zones are obscured by fog or poor lighting
conditions, pile driving at that location will not be initiated until
that zone is visible. Should such conditions arise while impact driving
is underway, the activity would be halted.
The shutdown and disturbance zones around the pile will be
monitored for the presence of marine mammals before, during, and after
any pile driving or removal activity.
One MMO will be placed in the most effective position near the
active construction/demolition platform in order to observe the
respective shutdown zones for vibratory and impact pile driving or for
applicable demolition activities. Monitoring would be primarily
dedicated to observing the shutdown zone; however, MMOs would record
all marine mammal sightings beyond these distances provided it did not
interfere with their effectiveness at carrying out the shutdown
procedures. Additional land, pier, or vessel-based MMOs will be
positioned to monitor the shutdown zones and the buffer zones, as
notionally indicated in Figures 3-3 and 3-4 of the Navy's application.
For all pile driving and applicable demolition activities, a
minimum of one observer shall monitor the shutdown zones. However, any
action requiring the impact or vibratory hammer will necessitate two
MMOs. For impact and vibratory pile driving of 16-in concrete piles,
two observers shall be positioned for optimal monitoring of the
surrounding waters.
The MMOs will record all visible marine mammal sightings. Confirmed
takes will be registered once the sightings data has been overlaid with
the isopleths identified in Table 5 and visualized in Figures 6-2, 6-3,
and 6-4 of the Navy's application, or based on refined acoustic data,
if amendments to the ZOIs are needed. Acousticians on duty may be
noting SPLs in real-time, but, to avoid biasing the observations, will
not communicate that information directly to the MMOs. These platforms
may move closer to, or farther from, the source depending on whether
received SPLs are less than or greater than the regulatory threshold
values. All MMOs will be in radio communication with each other so that
the MMOs will know when to anticipate incoming marine mammal species
and when they are tracking the same animals observed elsewhere.
If any species for which take is not authorized is observed by a
MMO during applicable construction or demolition activities, all
construction will be stopped immediately. Pile driving will commence if
the animal has not been seen inside the Level B ZOI for at least one
hour of observation. If the animal is resighted again, pile driving
will be stopped and a boat-based MMO (if available) will follow the
animal until it has left the Level B ZOI. If the animal is resighted
again, pile driving will be stopped and a boat-based MMO (if available)
will follow the animal until it has left the Level B ZOI.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. Monitoring biologists will
use their best professional judgment throughout implementation and seek
improvements to these methods when deemed appropriate. Any
modifications to protocol will be coordinated between NMFS and the
Navy.
Data Collection
We require that observers use approved data forms. Among other
[[Page 36378]]
pieces of information, the Navy 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 Navy will attempt to
distinguish between the number of individual animals taken and the
number of incidents 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 measured
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.
In addition, photographs would be taken of any gray whales
observed. These photographs would be submitted to NMFS' West Coast
Regional Office for comparison with photo-identification catalogs to
determine whether the whale is a member of the WNP population.
Reporting
A draft report would be submitted to NMFS within 45 calendar days
of the completion of marine mammal monitoring, or 60 days prior to the
issuance of any subsequent IHA for this project, whichever comes first.
The report will include marine mammal observations pre-activity,
during-activity, and post-activity during pile driving days, 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. A final report
would be prepared and submitted within thirty days following resolution
of comments on the draft report. Required contents of the monitoring
reports are described in more detail in the Navy's Acoustic and Marine
Species Monitoring Plan.
Monitoring Results From Previously Authorized Activities
The Navy complied with the mitigation and monitoring required under
the previous authorizations for this project. Acoustic and marine
mammal monitoring was implemented as required, with marine mammal
monitoring occurring before, during, and after each pile driving event.
During the course of Year 4 activities, the Navy did not exceed the
take levels authorized under the IHA (please see the Navy's monitoring
report for more details and below for further discussion).
The general objectives of the monitoring plan were similar to those
described above for the Year 5 monitoring plan. For acoustic
monitoring, the primary goal was to continue to collect in situ data
towards validation of the acoustic ZOIs defined based on previous data
collection efforts and using the transmission loss modeling effort
conducted prior to the start of the project, and to continue collection
of data on background noise conditions in San Diego Bay.
Acoustic Monitoring Results--For a full description of acoustic
monitoring methodology, please see section 2.3 of the Navy's monitoring
report, including Figure 2-3 for representative monitoring locations.
Results from Years 1-4 are displayed in Table 11. Please see our
notices of proposed IHAs for the Years 2, 3, and 4 IHAs (79 FR 53026,
September 5, 2014; 80 FR 53115, September 2, 2015; and 81 FR 66628,
September 28, 2016) or the Navy's Year 1 and 2 monitoring reports for
more detailed description of monitoring accomplished during the first
two years of the project.
For acoustic monitoring associated with impact pile driving,
continuous hydroacoustic monitoring systems were positioned at source
(10 m from the pile) and opportunistically at predicted 160-dB Level B
ZOIs. The far-field data collections were conducted at multiple
locations during impact driving of 16-in concrete-filled poly piles and
24 x 30-in concrete fender piles, i.e., approximately 20 to 550 m from
source. Hydrophones were deployed from the dock, barge, or moored
vessel at half the water depth. The SPLs for driving of 30-in steel
pipe piles were measured intermittently and archived (but not reported)
because associated SPLs for the size, type, and location of the piles
were previously validated. Source SPLs were recorded and analyzed for a
minimum of five piles for each of the concrete pile types. Additional
measurements were archived.
SPLs of pile driving and demolition activities conducted during
Year 2 fell within expected levels but varied spatially relative to the
existing fuel pier structure and maximum source levels for individual
piles (Table 11). For both vibratory and impact pile driving methods,
results from the IPP (Year 1) and 2014/2015 production pile driving
(Year 2) showed that transmission loss for piles driven in shallow
water inside of the existing fuel pier was greater than piles driven in
deep water outside of the existing pier. Differences in depth, sediment
type, and existing in-water pier/wharf structures likely accounted for
variations in transmission loss and measured differences in SPLs
recorded at the shutdown and far-field locations for shallow versus
deep piles of the same type and size. SPLs documented during vibratory
and impact pile driving of shallow and deep steel pipe piles of the
same size displayed notable differences in SPLs at shutdown range and
to a lesser extent at source.
Measurements of impact driving of concrete piles conducted during
Year 3 produced greater than expected SPLs at source. Differences in
the subsurface conditions may account for the discrepancy, as a
hardened layer is found at approximately 20-40 m below the mudline.
SPLs documented during driving of 16-in piles generally displayed
relatively low sound source levels during initial driving then
appreciable increases observed once the piles interacted with this
layer. Measurements from driving of the square concrete piles showed
greatest sound source levels during initial impact pile driving, which
then decreased once the piles transitioned through the hardened layer.
While source SPLs were observed to be greater than expected for both
pile types, attenuation was also greater. Despite greater than expected
source levels, the measured isopleth distances were similar to modeled
predictions. Far-field impact pile driving results varied substantially
between piles and locations for the various pile sizes, types, and
locations. Both pile types were driven adjacent to the new fuel pier
and source SPLs were subject to a wide variety of boundary conditions
from recently driven piles and associated pier infrastructure. Further
detail and discussion is provided in the Navy's report.
During Year 4, measurements were conducted for pile clipping,
caisson cutting, pile jetting, and airborne vibratory and impact
driving. The average SPLs for pile clipping at source ranged from 138.0
to 144.6 dB rms, with maximum SPLs at source ranging from
[[Page 36379]]
156.1 to 165.3 dB rms (see Table 6-3 of the Navy's monitoring report).
Measurements were conducted on eight piles and took one to three
minutes to cut.
Caisson demolition was conducted on 18 84-in concrete-filled
caissons, with an average duration of approximately 6 hours per
caisson. Underwater acoustic data was collected for seven caissons
using the vibratory setting. For some of the recordings, there were two
caissons being cut simultaneously and the acousticians captured the
SPLs for comparison between a single cutter versus two cutters. If two
cutters were running, the distance measured was from the closest
caisson to the location. Average SPLs at source for a single cutter
were 136.1 and 141.4 dB rms. Maximum SPLs at source for a single cutter
were 140.9 and 146.5 dB rms. Average SPLs at source for two cutters
running simultaneously were 146.5 and 149.0 dB rms. Maximum SPLs at
source for two cutters running simultaneously were 149.0 and 155.6 dB
rms. On average, there was a 10 dB difference between a single cutter
and two at source. Far-field recordings for a single cutter were
collected at far-field locations ranging from 20 to 430 m (66 to 1,411
ft), with documented maximum SPL values from 136.6 to 145.5 dB rms.
Far-field recordings for two cutters were also collected at far-field
locations ranging from 85 to 810 m (279 to 2,657 ft), with documented
maximum SPL values from 133.2 to 146.8 dB rms.
SPLs of pile installation activities for the 24 x 30 concrete piles
had not been previously documented. The only jetting data collected
during the Project was at NMAWC during the removal of 12-inch and 16-
inch concrete piles. A total of sixteen 24 x 30 concrete non-structural
fender piles were driven using two techniques: (1) Method 1 (M1)
utilized a custom-made spud jet with four nozzles welded to the tip
that used a high-pressure water system (900 gallons per minute with a
maximum pounds per square inch [psi] of 300), to make the initial break
through the bay point formation sediment layer; and (2) Method 2 (M2)
used the 24 x 30 pile, outfitted with two pipes inside the full length
of the pile, which then used a high-pressure water system (maximum psi
of 300) to remove sediment and place the pile. Pile jetting averaged
24.5 minutes per pile and acoustic recordings were collected for the
entire duration. Collection of underwater acoustic data were completed
on six piles using the vibratory setting. For M1, the average sound
pressure levels (SPL) at source ranged from 152.6 dB rms to 155.1 dB
rms, and maximum SPLs at source ranged from 156.5 dB rms to 159.9 dB
rms. For M2, the average SPL at source ranged from 133.0 dB to 149.8 dB
and maximum SPLs at source ranged from 137.1 dB to 153.2 dB rms. A
vessel based drift method was used to obtain far-field recordings
during M1 and M2 jetting techniques; the vessel was initially
positioned at the closest feasible distance to source, and then the
allowed to drift on the natural tidal current until near ambient sound
pressure levels were obtained. The SPLs at far-field for the first
drift during jetting M1 reached near ambient at 165 m (541 ft) from
pile with an SPL of 128.0 dB. The SPLs at far-field for the first drift
during pile jetting M2 reached near ambient at 80 m (262 ft) from pile
with an SPL of 127.6 dB. Recordings during the vessel drifts showed
that jetting reached near ambient levels for both methods between 80 m
(262 ft) and 165 m (541 ft; M1 and M2, respectively).
Airborne sound levels were recorded during vibratory pile driving
on fourteen 30-inch steel piles. The maximum recorded airborne dB rms
values at source was 106.3 dB re 20 [mu]Pa, and average values ranged
from 96.0 to 102.7 dB re 20 [mu]Pa. Airborne sound levels were recorded
during impact pile driving on sixteen 30-inch steel piles. The maximum
recorded airborne dB values at source was 118.5 dB re 20 [mu]Pa, and
average values ranged from 105.8 to 112.5 dB re 20 [mu]Pa. Further
detail and discussion is provided in the Navy's report.
Table 11--Acoustic Monitoring Results for Year 4
----------------------------------------------------------------------------------------------------------------
Average
Number of underwater Average
Location Activity Pile type piles SPL at 10 m airborne SPL
measured (dB rms) (LZFmax) \1\
----------------------------------------------------------------------------------------------------------------
Fuel Pier (Year 4)........... Pile Clipping... 24-in square 4 141 ..............
concrete pile.
Caisson 84-in caisson.. 10 136 ..............
Demolition (1
cutter).
Caisson 84-in caisson.. 8 138 ..............
Demolition (2
cutters).
Vibratory....... 30-in steel (at 7 .............. 100
source).
Vibratory....... 30-in steel 7 .............. 86
(far field).
Impact.......... 30-in steel (at 9 .............. 110
source).
Impact.......... 30-in steel 7 .............. 88
(far field).
NMAWC (Year 4)............... Pile Jetting.... 24x30.......... 10 147 ..............
----------------------------------------------------------------------------------------------------------------
\1\ Measured from Source (15.2 m) and Far-field Distances for 30-inch Steel Piles.
Marine Mammal Monitoring Results--Marine mammal monitoring was
conducted as required under the IHA and as described in the Year 4
monitoring plan and in our Federal Register notice of proposed
authorization associated with the Year 4 IHA. For a full description of
monitoring methodology, please see section 2 of the Navy's monitoring
report, including Figure 2-1, 2-2, and 2-7 for representative
monitoring locations and Figures 2-2 through 2-5 for monitoring zones.
Monitoring protocols were managed adaptively during the course of the
fourth-year IHA. Multiple shutdowns were implemented due to marine
mammals being observed within buffered shutdown zones, but no animals
were observed within actual predicted Level A harassment zones while
pile driving was occurring (one harbor seal was seen within the Level A
ZOI after a shutdown of construction had been implemented).
Monitoring results are presented in Table 12. The Navy recorded all
observations of marine mammals, including pre- and post-construction
monitoring efforts. Animals observed during these periods or that were
determined to be outside relevant ZOIs were not considered to represent
incidents of take. Please see Figures 3-11, 3-12, 3-22, 3-23, 3-30, and
3-31 of the Navy's Monitoring Report for locations of observations and
incidents of take relative to the project sites. Take authorization for
the second-year authorization was informed by an assumption that 115
days of in-water construction would occur, whereas only
[[Page 36380]]
fifty total days actually occurred. However, the actual observed rates
per day were in all cases lower than what was assumed. Therefore, we
expect that the Navy would not have exceeded the take allowances even
if the full 115 days had been reached.
There were considerably fewer individuals and sightings during the
Year 3 IHA when compared to the same months during the Year 2 IHA, and
only three species were observed. This may be due to environmental
fluctuations as part of the on-going El Ni[ntilde]o event. Water
temperatures during Year 3 were warmer than during the same months
during Year 2. Although the temperatures were still higher than the
average water temperatures for the region prior to the current El
Ni[ntilde]o event, it shows that the event may have been dissipating.
In addition, California sea lion strandings decreased. No evidently
significant behavioral changes were reported.
Similar to Year 3, there were considerably fewer individuals and
sightings during the Year 4 IHA when compared to the same months during
the Year 2 IHA, and only four species were observed. This may be due to
environmental fluctuations as part of the on-going El Ni[ntilde]o
event. Water temperatures during Year 4 were slightly warmer than
during the same months during Year 2. Although the temperatures were
still higher than the average water temperatures for the region prior
to the current El Ni[ntilde]o event, it shows that the event may have
been dissipating. In addition, California sea lion strandings
decreased, but may be returning to numbers more commonly observed. No
evidently significant behavioral changes were reported.
Table 12--Marine Mammal Monitoring Results for Year 4
----------------------------------------------------------------------------------------------------------------
Extrapolated
Total Total Observed incidents of Total
Species sightings individuals incidents of Level B take estimated
Level B take \1\ Level B take
----------------------------------------------------------------------------------------------------------------
California sea lion............. 717 2,037 156 1,835 1,991
Harbor seal..................... 87 102 21 57 78
Bottlenose dolphin.............. 18 45 4 144 148
Gray whale...................... 1 1 0 13 13
----------------------------------------------------------------------------------------------------------------
\1\ Assumed density and unmonitored area of assumed Level B ZOI used with actual pile driving time to generate
assumed take for unmonitored areas.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact in 50 CFR 216.103 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. 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).
Construction and demolition activities associated with the pier
replacement project, as outlined previously, have the potential to
disturb or displace marine mammals. Specifically, the specified
activities may result in take, in the form of Level B harassment
(behavioral disturbance) only, from underwater sounds generated from
pile driving. Potential takes could occur if individuals of these
species are present in the ensonified zone when pile driving or removal
is happening.
No injury, serious injury, or mortality is anticipated given the
nature of the activity 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. Impact pile driving
produces short, sharp pulses with higher peak levels and much sharper
rise time to reach those peaks. When impact driving is necessary,
required measures (implementation of buffered shutdown zones)
significantly reduce any possibility of injury. Given sufficient
``notice'' through use of soft start (for impact driving), marine
mammals are expected to move away from a sound source that is annoying
prior to its becoming potentially injurious. The likelihood that marine
mammal detection ability by trained observers is high under the
environmental conditions described for San Diego Bay (approaching 100
percent detection rate, as described by trained biologists conducting
site-specific surveys) further enables the implementation of shutdowns
to avoid injury, serious injury, or mortality.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from past
years of this project and 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; HDR, 2012; Lerma, 2014). Most likely,
individuals will simply 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. In response to vibratory driving, pinnipeds (which
may become somewhat habituated to human activity in industrial or urban
waterways) have been observed to orient towards and sometimes move
towards the sound. The pile driving activities analyzed here are
similar to, or less impactful than, numerous other construction
activities conducted in San Francisco Bay and in the Puget Sound
region, which have taken place with no
[[Page 36381]]
reported injuries or mortality to marine mammals, and no known long-
term adverse consequences from behavioral harassment. Repeated
exposures of individuals to levels of sound that may cause Level B
harassment are unlikely to result in hearing impairment or to
significantly disrupt foraging behavior. Thus, even repeated Level B
harassment of some small subset of the overall stock is unlikely to
result in any significant realized decrease in fitness for the affected
individuals, and thus would not result in any adverse impact to the
stock as a whole. Level B harassment will be reduced to the level of
least practicable impact through use of mitigation measures described
herein and, if sound produced by project activities is sufficiently
disturbing, animals are likely to simply avoid the project area while
the activity is occurring.
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;
The anticipated incidents of Level B harassment consist
of, at worst, temporary modifications in behavior;
The absence of any significant habitat within the project
area, including rookeries, significant haul-outs, or known areas or
features of special significance for foraging or reproduction; and
The presumed efficacy of the proposed mitigation measures
in reducing the effects of the specified activity to the level of least
practicable impact.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(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.
The number of incidents of take proposed for authorization for
these stocks, with the exception of the coastal bottlenose dolphin (see
below), would be considered small relative to the relevant stocks or
populations (see Table 9) even if each estimated taking occurred to a
new individual. This is an extremely unlikely scenario as, for
pinnipeds occurring at the NBPL waterfront, there will almost certainly
be some overlap in individuals present day-to-day and in general, there
is likely to be some overlap in individuals present day-to-day for
animals in estuarine/inland waters.
The proposed numbers of authorized take for bottlenose dolphins are
higher relative to the total stock abundance estimate and would not
represent small numbers if a significant portion of the take was for a
new individual. However, these numbers represent the estimated
incidents of take, not the number of individuals taken. That is, it is
likely that a relatively small subset of California coastal bottlenose
dolphins would be incidentally harassed by project activities.
California coastal bottlenose dolphins range from San Francisco Bay to
San Diego (and south into Mexico) and the specified activity would be
stationary within an enclosed water body that is not recognized as an
area of any special significance for coastal bottlenose dolphins (and
is therefore not an area of dolphin aggregation, as evident in Navy
observational records). We therefore believe that the estimated numbers
of takes, were they to occur, likely represent repeated exposures of a
much smaller number of bottlenose dolphins and that, based on the
limited region of exposure in comparison with the known distribution of
the coastal bottlenose dolphin, these estimated incidents of take
represent small numbers of bottlenose dolphins.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species or stocks.
Impact on Availability of Affected Species for Taking for Subsistence
Uses
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
preliminarily determined that the total taking of affected species or
stocks would not have an unmitigable adverse impact on the availability
of such species or stocks for taking for subsistence purposes.
Endangered Species Act (ESA)
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally, in this case with the ESA Interagency
Cooperation Division, whenever we propose to authorize take for
endangered or threatened species.
The Navy initiated informal consultation under section 7 of the ESA
with NMFS Southwest Regional Office (now West Coast Regional Office) on
March 5, 2013. NMFS concluded on May 16, 2013, that the proposed action
may affect, but is not likely to adversely affect, WNP gray whales. The
Navy has not requested authorization of the incidental take of WNP gray
whales and no such authorization is proposed, and there are no other
ESA-listed marine mammals found in the action area. Therefore, no
consultation under the ESA is required.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the Navy for conducting the described pier replacement
activities in San Diego Bay, for a period of one year from the date of
issuance, provided the previously mentioned mitigation, monitoring, and
reporting requirements are incorporated. This section contains a draft
of the IHA itself. The wording contained in this section is proposed
for inclusion in the IHA (if issued).
1. This Incidental Harassment Authorization (IHA) is valid from
October 8, 2017, through October 7, 2018.
2. This IHA is valid only for pile driving and removal activities
associated with the Fuel Pier Replacement Project at the Naval Station
Point Loma in San Diego Bay, California.
[[Page 36382]]
3. General Conditions
(a) A copy of this IHA must be in the possession of the Navy, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species authorized for taking are the harbor seal (Phoca
vitulina richardii), California sea lion (Zalophus californianus),
bottlenose dolphin (Tursiops truncatus truncatus), common dolphin
(Delphinus delphis), northern elephant seal (Mirounga angustirostris),
Pacific white-sided dolphin (Lagenorhynchus obliquidens), Risso's
dolphin (Grampus griseus), and gray whale (Eschrichtius robustus).
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b). See Table 1 for numbers of take
authorized.
Table 1--Authorized Take Numbers, by Species
------------------------------------------------------------------------
Authorized
Species take
------------------------------------------------------------------------
California sea lion..................................... 8,971
Harbor seal............................................. 281
Northern elephant seal.................................. 43
California coastal bottlenose dolphin................... 704
Common dolphin.......................................... 861
Pacific white-sided dolphin............................. 28
Risso's dolphin......................................... 114
Gray whale.............................................. 10
------------------------------------------------------------------------
(d) The taking by injury (Level A harassment), serious injury, or
death of any of the species listed in condition 3(b) of the
Authorization or any taking of any other species of marine mammal is
prohibited and may result in the modification, suspension, or
revocation of this IHA.
(e) The Navy shall conduct briefings between construction
supervisors and crews, marine mammal monitoring team, acoustic
monitoring team, and Navy staff prior to the start of all pile driving
activity, and when new personnel join the work, in order to explain
responsibilities, communication procedures, marine mammal monitoring
protocol, and operational procedures.
4. Mitigation Measures
The holder of this Authorization is required to implement the
following mitigation measures:
(a) For all pile driving, the Navy shall implement a minimum
shutdown zone of 10 m radius around the pile. If a marine mammal comes
within or approaches the shutdown zone, such operations shall cease.
See Table 2 for minimum radial distances required for shutdown zones.
Table 2--Radial Distance to Shutdown and Disturbance Zones Associated With Relevant Thresholds, Including Buffers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Monitored distances to thresholds (meters)
---------------------------------------------------------------------------------------
Underwater Airborne
---------------------------------------------------------------------------------------
Activity Level A Level B Level B
---------------------------------------------------------------------------------------
120 dB
LF \1\ MF \1\ PW \1\ OW \1\ 160 dB \2\ 100 dB 90 dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
Old Fuel Pier and Temporary Mooring Dolphin Demolition
--------------------------------------------------------------------------------------------------------------------------------------------------------
66-inch and 84-inch caissons (Diamond saw cutting).............. 10 N/A 631 N/A \3\
--------------------------------------------
Concrete piles (Pile clipping).................................. 10 N/A 2,511
------------------------------------------------------------------
30-inch steel piles (Plasma torch cutting)...................... 10
N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMAWC Construction and Demolition
--------------------------------------------------------------------------------------------------------------------------------------------------------
16-inch concrete piles (Vibratory extraction/driving)........... 20 \4\
10 N/A 1,848 42 149
--------------------------------------------
16-inch concrete piles (Impact driving)......................... 100 \5\
60 \6\ 270 N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
16-inch concrete piles (Jetting pile extraction)................ 10 N/A 1,165 N/A \3\
------------------------------------------------------------------
16-inch concrete piles (Pile dead-pull)......................... 10
N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ LF = Low-frequency cetaceans; MF = Mid-frequency cetaceans; PW = Phocid pinnipeds; OW = Otariid pinnipeds. The high-frequency cetacean hearing group
(HF) is omitted, because no species in the hearing group occur in, or around, Project area.
\2\ Mean ambient sound levels in San Diego Bay are approximately 128 dB rms (NAVFAC SW 2015), and all 120 dB Level B ZOIs are based on the ambient
value.
\3\ Airborne noise levels did not exceed regulatory thresholds during previous IHAs. No airborne monitoring will take place for diamond saw cutting of
caissons, plasma torch cutting of temporary mooring dolphin 30-inch steel piles, jetting or dead-pull extraction of concrete piles.
\4\ Includes buffer of calculated Level A threshold out to 20 m (65.6 ft).
\5\ Includes buffer of calculated Level A threshold out to 100 m (328 ft).
\6\ Includes buffer of calculated Level A threshold out to 60 m (197 ft).
(b) The Navy shall shutdown activity as appropriate upon
observation of any species for which take is not authorized. Activity
shall not be resumed until those species have been observed to leave
the relevant zone or until one hour has elapsed.
(c) The Navy shall deploy marine mammal observers as described
below and as indicated in the Acoustic and Marine Species Monitoring
Plan (Monitoring Plan; attached).
i. For all pile driving and applicable demolition activities, a
minimum of one observer shall monitor the shutdown zones. However, any
action requiring the impact or vibratory hammer will necessitate two
MMOs.
ii. For impact and vibratory pile driving of 16-in concrete piles,
two observers shall be positioned for optimal monitoring of the
surrounding waters.
[[Page 36383]]
iii. These observers shall record all observations of marine
mammals, regardless of distance from the pile being driven, as well as
behavior and potential behavioral reactions of the animals.
iv. All observers shall be equipped for communication of marine
mammal observations amongst themselves and to other relevant personnel
(e.g., those necessary to effect activity delay or shutdown).
(d) Monitoring shall take place from fifteen minutes prior to
initiation of pile driving activity through thirty minutes post-
completion of pile driving activity. Pre-activity monitoring shall be
conducted for fifteen minutes to ensure that the shutdown zone is clear
of marine mammals, and pile driving may commence when observers have
declared the shutdown zone clear of marine mammals. In the event of a
delay or shutdown of activity resulting from marine mammals in the
shutdown zone, animals shall be allowed to remain in the shutdown zone
(i.e., must leave of their own volition) and their behavior shall be
monitored and documented. Monitoring shall occur throughout the time
required to drive a pile. The shutdown zone must be determined to be
clear during periods of good visibility (i.e., the entire shutdown zone
and surrounding waters must be visible to the naked eye).
(e) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted. If pile
driving is halted or delayed due to the presence of a marine mammal,
the activity may not commence or resume until either the animal has
voluntarily left and been visually confirmed beyond the shutdown zone
or 30 minutes have passed without re-detection of gray whales or 15
minutes for all other animals.
(f) Monitoring shall be conducted by qualified observers, as
described in the Monitoring Plan. 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.
(g) The Navy shall use soft start techniques recommended by NMFS
for impact pile driving. Soft start for impact drivers requires
contractors to provide an initial set of strikes at reduced energy,
followed by a thirty-second waiting period, then two subsequent reduced
energy strike sets. Soft start shall 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.
(h) Pile driving shall only be conducted during daylight hours.
5. Monitoring
The holder of this Authorization is required to conduct marine
mammal monitoring during pile driving activity. Marine mammal
monitoring and reporting shall be conducted in accordance with the
Monitoring Plan.
(a) The Navy shall collect sighting data and behavioral responses
to pile driving for marine mammal species observed in the region of
activity during the period of activity. All observers shall be trained
in marine mammal identification and behaviors, and shall have no other
construction-related tasks while conducting monitoring.
(b) For all marine mammal monitoring, the information shall be
recorded as described in the Monitoring Plan.
(c) The Navy shall conduct acoustic monitoring for representative
scenarios of pile driving activity, as described in the Monitoring
Plan.
6. Reporting
The holder of this Authorization is required to:
(a) Submit a draft report on all monitoring conducted under the IHA
within 45 calendar days of the completion of marine mammal and acoustic
monitoring, or 60 days prior to the issuance of any subsequent IHA for
this project, whichever comes first. A final report shall be prepared
and submitted within thirty days following resolution of comments on
the draft report from NMFS. This report must contain the informational
elements described in the Monitoring Plan, at minimum (see attached),
and shall also include:
i. 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.
ii. Description of attempts to distinguish between the number of
individual animals taken and the number of incidences of take, such as
ability to track groups or individuals.
iii. Results of acoustic monitoring, including the information
described in in the Monitoring Plan.
(b) Reporting injured or dead marine mammals:
i. In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this IHA,
such as an injury (Level A harassment), serious injury, or mortality,
Navy shall immediately cease the specified activities and report the
incident to the Office of Protected Resources, NMFS, and the West Coast
Regional Stranding Coordinator, NMFS. The report must include the
following information:
A. Time and date of the incident;
B. Description of the incident;
C. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
D. Description of all marine mammal observations in the 24 hours
preceding the incident;
E. Species identification or description of the animal(s) involved;
F. Fate of the animal(s); and
G. Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with Navy to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. Navy may not resume
their activities until notified by NMFS.
i. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), Navy shall immediately report
the incident to the Office of Protected Resources, NMFS, and the West
Coast Regional Stranding Coordinator, NMFS.
The report must include the same information identified in 6(b)(i)
of this IHA. Activities may continue while NMFS reviews the
circumstances of the incident. NMFS will work with Navy to determine
whether additional mitigation measures or modifications to the
activities are appropriate.
ii. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, scavenger damage), Navy shall report the incident to the
Office of Protected Resources, NMFS, and the West Coast Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. Navy
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
the authorized taking is having more than a negligible impact on the
species or stock of affected marine mammals.
[[Page 36384]]
Request for Public Comments
We request comment on our analysis, the draft authorization, and
any other aspect of this Notice of Proposed IHA for Navy's pier
replacement activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on Navy's request for an MMPA authorization.
Dated: August 1, 2017.
Catherine Marzin,
Acting Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2017-16453 Filed 8-3-17; 8:45 am]
BILLING CODE 3510-22-P