[Federal Register Volume 78, Number 8 (Friday, January 11, 2013)]
[Notices]
[Pages 2371-2377]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-00381]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XA933
Taking of Marine Mammals Incidental to Specified Activities;
Construction of the East Span of the San Francisco-Oakland Bay Bridge
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of issuance of an incidental harassment authorization.
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SUMMARY: In accordance with provisions of the Marine Mammal Protection
Act (MMPA) as amended, notification is hereby given that an Incidental
Harassment Authorization (IHA) has been issued to the California
Department of Transportation (CALTRANS) to take small numbers of
California sea lions, Pacific harbor seals, harbor porpoises, and gray
whales, by harassment, incidental to construction of a replacement
bridge for the East Span of the San Francisco-Oakland Bay Bridge (SF-
OBB) in California.
DATES: This authorization is effective from January 8, 2013, until
January 7, 2014.
ADDRESSES: A copy of the application, IHA, and/or a list of references
used in this document may be obtained by writing to P. Michael Payne,
Chief, Permits, Conservation and Education Division, Office of
Protected Resources, National Marine Fisheries Service, 1315 East-West
Highway, Silver Spring, MD 20910.
FOR FURTHER INFORMATION CONTACT: Shane Guan, NMFS, (301) 427-8418, ext
137, or Monica DeAngelis, NMFS, (562) 980-3232.
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 to allow, upon request, the
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, the taking is
limited to harassment, notice of a proposed authorization is provided
to the public for review.
Permission shall be granted if NMFS finds that the taking will have
a negligible impact on the species or
[[Page 2372]]
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for certain subsistence uses
and if the permissible methods of taking and requirements pertaining to
the mitigation, monitoring, and reporting of such taking 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.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the United States can apply for an authorization
to incidentally take small numbers of marine mammals by harassment.
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].''
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS
review of an application followed by a 30-day public notice and comment
period on any proposed authorizations for the incidental harassment of
small numbers of marine mammals. Within 45 days of the close of the
comment period, NMFS must either issue or deny issuance of the
authorization.
Summary of Request
On October 19, 2011, CALTRANS submitted a request to NOAA
requesting an IHA for the possible harassment of small numbers of
California sea lions (Zalophus californianus), Pacific harbor seals
(Phoca vitulina richardsii), harbor porpoises (Phocoena phocoena), and
gray whales (Eschrichtius robustus) incidental to construction
associated with a replacement bridge for the East Span of the SF-OBB,
in San Francisco Bay (SFB), California. The proposed construction
activities would last for approximately three years, starting 2013.
After receiving NMFS comments on the IHA application regarding proposed
monitoring measures, CALTRANS submitted a revised IHA application on
April 23, 2012. The action discussed in this document is based on
CALTRANS April 23, 2012, IHA application and NMFS Federal Register
notice for the proposed IHA (77 FR 50473; August 21, 2012).
An IHA was previously issued to CALTRANS for this activity on
February 7, 2011 and it expired on February 6, 2012 (76 FR 7156,
February 9, 2011). No in-water construction activity was conducted
during the period covered by that IHA. CALTRANS' renewal application
indicates that the next stage of the construction activities will
involve dismantling of the existing bridge, which is expected to start
in fall 2013. However, some preparatory construction activities related
to the dismantling may take place before the planned schedule. A
detailed description of the proposed SF-OBB East Span project is
provided in the CALTRANS' IHA application and in the Federal Register
for the proposed IHA (77 FR 50473, August 21, 2012), and there is no
change to the description of the activities. Therefore, the detailed
description of the proposed construction activities is not repeated
here, except for certain information that was missing in the earlier
documents.
Supplemental Information Regarding CALTRANS Construction Activities
As stated in the IHA application and the Federal Register notice
for the proposed IHA (77 FR 50473; August 21, 2012), work at the Yerba
Buena Island (YBI) access would involve the construction of a small
(approximately 650 m\2\, or 7,000 ft\2\) H-pile supported trestle. The
size of the H-pile was not identified in the proposed IHA. Discussion
with CALTRANS indicated that it is unclear the size of the H-piles
would be used. However, it is known that the contractor would most
likely use HP H-piles, which with dimensions between 9.70 x 10.075 in.
and 14.21 x 14.885 in., with length between 25 and 100 feet.
CALTRANS also stated that it's very unlikely that multiple pile
driving would occur simultaneously. If in the case that more than one
contractor would be employed to conduct the construction activity,
maximum of two pile work could occur and most likely it would be one
pile driving and one pile removal.
In addition, NMFS also worked with CALTRANS to revise the size of
the exclusion zones and Level B harassment zones due to the lack of on-
site data to establish specific zones for driving of 24- and 36-in
piles, H-piles, and sheet piles. CALTRANS agreed that it will use the
data of 48-in piles to establish the temporary exclusion zones and
Level B harassment zones based on in-situ measurements conducted in
2009 (CALTRANS 2009) before revised zones are established based on on-
site measurements during the test pile driving. Likewise, for vibratory
pile driving, if hydroacoustic monitoring indicates that sound levels
have the potential to exceed the 180 or 190 dB SPL, corresponding
exclusion zones will be established. The temporary exclusion zones and
Level B zones for various pile driving and dismantling activities are
listed in Table 1.
Table 1--Temporary Exclusion and Level B Harassment Zones for Various Pile Driving and Dismantling Activities
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Distance to 120 dB re Distance to 160 dB re Distance to 180 dB re Distance to 190 dB re
Pile driving/dismantling activities Pile size (m) 1 [micro]Pa (rms) (m) 1 [micro]Pa (rms) (m) 1 [micro]Pa (rms) (m) 1 [micro]Pa (rms) (m)
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Vibratory Driving.................. 24.................... 2,000................. NA................... NA................... NA
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36.................... 2,000................. NA................... NA................... NA
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Sheet pile............ 2,000................. NA................... NA................... NA
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Attenuated Impact Driving.......... 24.................... NA.................... 1,000................ 235.................. 95
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36.................... NA.................... 1,000................ 235.................. 95
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Unattenuated Proofing.............. 24.................... NA.................... 1,000................ 235.................. 95
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[[Page 2373]]
36.................... NA.................... 1,000................ 235.................. 95
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Unattenuated Impact Driving........ H-pile................ NA.................... 1,000................ 235.................. 95
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Dismantling........................ ...................... 2,000................. NA................... 100.................. 100
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Comments and Responses
A notice of receipt and request for public comment on the
application and proposed authorization was published on August 21, 2012
(77 FR 50473). During the 30-day public comment period, the Marine
Mammal Commission (Commission) provided the only comment.
Comment 1: The Commission recommends that NMFS promulgate
regulations and condition them to require further public review if
CALTRANS or the contractor proposes any substantial changes to the
project plan.
Response: In the Federal Register notice for the proposed IHA (77
FR 50473; August 21, 2012), NMFS noted that CALTRANS' dismantling of
the existing east span SF-OBB may take up to five years to complete,
therefore, a five-year letter of authorization (LOA) under a rulemaking
may seem to be preferable. However, subsequent discussion with CALTRANS
indicated that activities involving the existing bridge dismantling are
likely to differ from year to year, and the agency may not be able to
predict annual construction activities in advance. Further, the
proposed dismantling activities could be completed in two to three
years. Therefore, at this stage, NMFS concludes that the current best
course of action for CALTRANS is to pursue annual IHAs.
Comment 2: The Commission requests NMFS require CALTRANS to
implement full-time monitoring of Level A and B harassment zones during
all in-water sound-producing activities (i.e., pile-driving and removal
and bridge dismantlement activities).
Response: NMFS discussed with CALTRANS on marine mammal monitoring
during its proposed in-water construction activities. As described in
the Federal Register notice for the proposed IHA (77 FR 50473; August
21, 2012) and in CALTRANS IHA application, CALTRANS' planned
construction includes an average annual installation of up to 635
temporary falsework piles, 1,925 steel sheet piles, and various
mechanical dismantling activities. The extent of the work made it
infeasible and costly to implement marine mammal monitoring for Level A
and B harassment zones at all times, particularly since some of the
Level B harassment zone for vibratory pile driving extends to a radius
of 2 km. CALTRANS agrees to monitor the 180 and 190 dB exclusion zones
and 160 dB behavioral harassment zone for all unattenuated impact pile
driving of H-piles, and the 180 and 190 dB exclusion zones for
attenuated impact pile driving and mechanical dismantling. CALTRANS
will also monitor the 160 dB behavioral harassment zone for 20% of the
attenuated impact pile driving, and 120 dB behavioral harassment zone
for 20% of vibratory pile driving and mechanic dismantling. However,
CALTRANS will not monitor the unattenuated impact pile proofing, which
only lasts for less than one minute. Proposed proofing of piles will be
limited to a maximum of two piles per day, and for less than 1 minute
per pile, administering a maximum of twenty blows per pile. CALTRANS
states, and NMFS agrees, that the logistics of scheduling and
mobilizing a monitoring team for activities that will last less than
one minute is not practical.
Description of Marine Mammals in the Area of the Specified Activity
General information on the marine mammal species found in
California waters can be found in Caretta et al. (2011), which is
available at the following URL: http://www.nmfs.noaa.gov/pr/pdfs/sars/po2010.pdf. Refer to that document for information on these species.
The marine mammals most likely to be found in the SF-OBB area are
the California sea lion, Pacific harbor seal, and harbor porpoise. From
December through May gray whales may also be present in the SF-OBB
area. Information on California sea lion, harbor seal, and gray whale
was provided in the November 14, 2003 (68 FR 64595), Federal Register
notice; information on harbor porpoise was provided in the January 26,
2006 (71 FR 4352), Federal Register notice.
Potential Effects on Marine Mammals and Their Habitat
CALTRANS and NMFS have determined that open-water pile driving and
pile removal, as well as dredging and dismantling of concrete
foundation of existing bridge by saw cutting, flame cutting, mechanical
splitting, drilling, pulverizing and/or hydro-cutting, as outlined in
the project description, has the potential to result in behavioral
harassment of California sea lions, Pacific harbor seals, harbor
porpoises, and gray whales that may be swimming, foraging, or resting
in the project vicinity while pile driving is being conducted. Pile
driving and removal could potentially harass those few pinnipeds that
are in the water close to the project site, whether their heads are
above or below the surface.
Marine mammals exposed to high intensity sound repeatedly or for
prolonged periods can experience hearing threshold shift (TS), which is
the loss of hearing sensitivity at certain frequency ranges (Kastak et
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be
permanent (PTS), in which case the loss of hearing sensitivity is
unrecoverable, or temporary (TTS), in which case the animal's hearing
threshold will recover over time (Southall et al. 2007). Since marine
mammals depend on acoustic cues for vital biological functions, such as
orientation, communication, finding prey, and avoiding predators,
marine mammals that suffer from PTS or TTS could have reduced fitness
in survival and reproduction, either permanently or temporarily.
Repeated noise exposure that leads to TTS could cause PTS.
Measured source levels from impact pile driving can be as high as
214 dB re 1 [mu]Pa @ 1 m. Although no marine mammals have been shown to
experience TTS or PTS as a result of being exposed to pile driving
activities, experiments on a bottlenose dolphin (Tursiops truncates)
and beluga whale
[[Page 2374]]
(Delphinapterus leucas) showed that exposure to a single watergun
impulse at a received level of 207 kPa (or 30 psi) peak-to-peak (p-p),
which is equivalent to 228 dB (p-p) re 1 [mu]Pa, resulted in a 7 and 6
dB TTS in the beluga whale at 0.4 and 30 kHz, respectively. Thresholds
returned to within 2 dB of the pre-exposure level within 4 minutes of
the exposure (Finneran et al. 2002). No TTS was observed in the
bottlenose dolphin. Although the source level of pile driving from one
hammer strike is expected to be much lower than the single watergun
impulse cited here, animals being exposed for a prolonged period to
repeated hammer strikes could receive more noise exposure in terms of
SEL than from the single watergun impulse (estimated at 188 dB re 1
[mu]Pa\2\-s) in the aforementioned experiment (Finneran et al. 2002).
Noises from dismantling of marine foundations by mechanical means
include, but are not limited to, saw cutting, mechanical splitting,
drilling and pulverizing. Saw cutting and drilling constitute non-pulse
noise, whereas mechanical splitting and pulverizing constitute impulse
noise. Although the characteristics of these noises are not well
studied, noises from saw cutting and drilling are expected to be
similar to vibratory pile driving, and noises from mechanical splitting
and pulverizing are expected to be similar to impact pile driving, but
at lower intensity, due to the similar mechanisms in sound generating
but at a lower power outputs. CALTRANS states that drilling and saw
cutting are anticipated to produce underwater sound pressure levels
(SPLs) in excess of 120 dB RMS, but are not anticipated to exceed the
180 dB re 1 [mu]Pa (RMS). The mechanical splitting and pulverizing of
concrete with equipment such as a hammer hoe has the potential to
generate high sound pressure levels in excess of 190 dB re 1 [mu]Pa
(RMS) at 1 m.
However, in order for marine mammals to experience TTS or PTS, the
animals have to be close enough to be exposed to high intensity noise
levels for prolonged period of time. Based on the best scientific
information available, these sound levels are far below the threshold
that could cause TTS or the onset of PTS.
In addition, chronic exposure to excessive, though not high-
intensity, noise could cause masking at particular frequencies for
marine mammals that utilize sound for vital biological functions.
Masking can interfere with detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, under certain circumstances,
marine mammals whose acoustical sensors or environment are being
severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction.
Masking occurs at the frequency band which the animals utilize.
Therefore, since noise generated from in-water pile driving during the
SF-OBB construction activities is mostly concentrated at low frequency
ranges, it may have less effect on high frequency echolocation sounds
by harbor porpoises. However, lower frequency man-made noises are more
likely to affect detection of communication calls and other potentially
important natural sounds such as surf and prey noise. It may also
affect communication signals when they occur near the noise band and
thus reduce the communication space of animals (e.g., Clark et al.
2009) and cause increased stress levels (e.g., Foote et al. 2004; Holt
et al. 2009).
Unlike TS, masking can potentially impact the species at
population, community, or even ecosystem levels, as well as individual
levels. Masking affects both senders and receivers of the signals and
could have long-term chronic effects on marine mammal species and
populations. Recent science suggests that low frequency ambient sound
levels have increased by as much as 20 dB (more than 3 times in terms
of SPL) in the world's ocean from pre-industrial periods, and most of
these increases are from distant shipping (Hildebrand 2009). All
anthropogenic noise sources, such as those from vessels traffic, pile
driving, dredging, and dismantling existing bridge by mechanic means,
contribute to the elevated ambient noise levels, thus intensify
masking.
Nevertheless, the sum of noise from the proposed SF-OBB
construction activities is confined in an area of inland waters (San
Francisco Bay) that is bounded by landmass, therefore, the noise
generated is not expected to contribute to increased ocean ambient
noise. Due to shallow water depth near the Oakland shore, dredging
activities are mainly used to create a barge access channel to
dismantle the existing bridge. Therefore, underwater sound propagation
from dredging is expected to be poor due to the extreme shallowness of
the area to be dredged.
Finally, exposure of marine mammals to certain sounds could lead to
behavioral disturbance (Richardson et al. 1995), such as: Changing
durations of surfacing and dives, number of blows per surfacing, or
moving direction and/or speed; reduced/increased vocal activities,
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping), avoidance of
areas where noise sources are located, and/or flight responses (e.g.,
pinnipeds flushing into water from haulouts or rookeries).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, and reproduction. Some of these
significant behavioral modifications include:
Drastic change in diving/surfacing patterns (such as those
thought to be causing beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cessation of feeding or social interaction.
For example, at the Guerreo Negro Lagoon in Baja California,
Mexico, which is one of the important breeding grounds for Pacific gray
whales, shipping and dredging associated with a salt works may have
induced gray whales to abandon the area through most of the 1960s
(Bryant et al. 1984). After these activities stopped, the lagoon was
reoccupied, first by single whales and later by cow-calf pairs.
The onset of behavioral disturbance from anthropogenic noise
depends on both external factors (characteristics of noise sources and
their paths) and the receiving animals (hearing, motivation,
experience, demography) and is also difficult to predict (Southall et
al. 2007).
The proposed project area is not believed to be a prime habitat for
marine mammals, nor is it considered an area frequented by marine
mammals. Therefore, behavioral disturbances that could result from
anthropogenic noise associated with SF-OBB construction activities are
expected to affect only a small number of marine mammals on an
infrequent basis.
Currently NMFS uses 160 dB re 1 [mu]Pa (RMS) at received level for
impulse noises (such as impact pile driving, mechanic splitting and
pulverizing) as the onset of marine mammal behavioral harassment, and
120 dB re 1 [mu]Pa (RMS) for non-impulse noises (vibratory pile
driving, saw cutting, drilling, and dredging).
As far as airborne noise is concerned, based on airborne noise
levels measured and on-site monitoring conducted during 2004 under a
previous IHA,
[[Page 2375]]
noise levels from the East Span project did not result in the
harassment of harbor seals hauled out on Yerba Buena Island (YBI).
Also, noise levels from the East Span project are not expected to
result in harassment of the sea lions hauled out at Pier 39 as airborne
and waterborne sound pressure levels (SPLs) would attenuate to levels
below where harassment would be expected by the time they reach that
haul-out site, 5.7 km (3.5 miles) from the project site. Therefore, no
pinniped hauled out would be affected as a result of the proposed pile-
driving. A detailed description of the acoustic measurements is
provided in the 2004 CALTRANS marine mammal and acoustic monitoring
report for the same activity (CALTRANS' 2005).
Short-term impacts to habitat may include minimal disturbance of
the sediment where individual bridge piers are constructed. Long-term
impacts to marine mammal habitat will be limited to the footprint of
the piles and the obstruction they will create following installation.
However, this impact is not considered significant as the marine
mammals can easily swim around the piles of the new bridge, as they
currently swim around the existing bridge piers.
Impact on Availability of Affected Species for Taking for Subsistence
Uses
There are no relevant subsistence uses of marine mammals implicated
by this action.
Mitigation Measures
For the issuance of the IHA for the planned 2012-2013 SF-OBB
construction activities to reduce adverse impacts to marine mammals to
the lowest extent practicable, NMFS requires the following mitigation
measures to be implemented.
Use of Noise Attenuation Devices
To reduce impact on marine mammals, CALTRANS shall use marine pile
driving energy attenuator (i.e., air bubble curtain system), or other
equally effective sound attenuation method (e.g., dewatered cofferdam)
for all impact pile driving, with the exception of pile proofing.
Establishment of Exclusion and Level B Harassment Zones
Before the commencement of in-water construction activities, which
include impact pile driving, vibratory pile driving, and mechanical
dismantling of existing bridge, CALTRANS shall establish exclusion
zones where received underwater sound pressure levels (SPLs) are higher
than 180 dB (rms) and 190 dB (rms) re 1 [micro]Pa for cetaceans and
pinnipeds, respectively, and Level B behavioral harassment zones where
received underwater sound pressure levels (SPLs) are higher than 160 dB
(rms) and 120 dB (rms) re 1 [micro]Pa for impulse noise sources (impact
pile driving) and non-impulses noise sources (vibratory pile driving
and mechanic dismantling), respectively. Before the sizes of actual
zones are determined based on hydroacoustic measurements, CALTRANS
shall establish these zones based on prior measurements conducted
during SF-OBB constructions, as described in Table 1 of this document.
Once the underwater acoustic measurements are conducted during
initial test pile driving, CALTRANS shall adjust the size of the
exclusion zones and Level B behavioral harassment zones, and monitor
these zones accordingly.
NMFS-approved protected species observers (PSOs) shall conduct
initial survey of the safety zone to ensure that no marine mammals are
seen within the zones before impact pile driving of a pile segment
begins. If marine mammals are found within the safety zone, impact pile
driving of the segment would be delayed until they move out of the
area. If a marine mammal is seen above water and then dives below, the
contractor would wait 15 minutes for pinnipeds and harbor porpoise and
30 minutes for gray whales. If no marine mammals are seen by the
observer in that time it would be assumed that the animal has moved
beyond the safety zone. This 15-minute criterion is based on scientific
evidence that harbor seals in San Francisco Bay dive for a mean time of
0.50 minutes to 3.33 minutes (Harvey and Torok, 1994), and the mean
diving duration for harbor porpoises ranges from 44 to 103 seconds
(Westgate et al., 1995).
Once the pile driving of a segment begins it cannot be stopped
until that segment has reached its predetermined depth due to the
nature of the sediments underlying the Bay. If pile driving stops and
then resumes, it would potentially have to occur for a longer time and
at increased energy levels. In sum, this would simply amplify impacts
to marine mammals, as they would endure potentially higher SPLs for
longer periods of time. Pile segment lengths and wall thickness have
been specially designed so that when work is stopped between segments
(but not during a single segment), the pile tip is never resting in
highly resistant sediment layers. Therefore, because of this
operational situation, if seals, sea lions, or harbor porpoises enter
the safety zone after pile driving of a segment has begun, pile driving
will continue and marine mammal observers will monitor and record
marine mammal numbers and behavior. However, if pile driving of a
segment ceases for 30 minutes or more and a marine mammal is sighted
within the designated safety zone prior to commencement of pile
driving, the observer(s) must notify the Resident Engineer (or other
authorized individual) immediately and follow the mitigation
requirements as outlined previously in this document.
Soft Start
It should be recognized that although marine mammals will be
protected from Level A harassment (i.e., injury) through marine mammal
observers monitoring a 190-dB exclusion zone for pinnipeds and 180-dB
exclusion zone for cetaceans, mitigation may not be 100 percent
effective at all times in locating marine mammals. Therefore, in order
to provide additional protection to marine mammals near the project
area by allowing marine mammals to vacate the area prior to receiving a
potential injury, CALTRANS and its contractor will also ``soft start''
the hammer prior to operating at full capacity. This should expose
fewer animals to loud sounds both underwater and above water. This
would also ensure that, although not expected, any pinnipeds and
cetaceans that are missed during the initial exclusion zone monitoring
will not be injured.
Power Down and Shut-Down
As mentioned previously, although power down and shut-down measures
will not be required for pile driving activities, these measures are
required for mechanical dismantling of the existing bridge. The
contractor perform mechanical dismantling work will stop in-water noise
generating machinery when marine mammals are sighted within the
designated exclusion zones.
Monitoring Measures
The following monitoring measures are required for the proposed SF-
OBB construction activities.
Visual Monitoring
Besides using mitigation measures as a mean of implementing power
down and shut-down measures for mechanical bridge dismantling, marine
mammal monitoring will also be conducted to assess potential impacts
from CALTRANS construction activities. CALTRANS will implement onsite
marine mammal monitoring for 100% of all unattenuated impact pile
driving of H-piles for 180- and 190-dB re 1 [micro]Pa exclusion zones
and 160-dB re 1 [micro]Pa
[[Page 2376]]
Level B harassment zone, attenuated impact pile driving (except pile
proofing) and mechanical dismantling for 180- and 190-dB re 1 [micro]Pa
exclusion zones. CALTRANS will also monitor 20% of the attenuated
impact pile driving for the 160-dB re 1 [micro]Pa Level B harassment
zone, and 20% of vibratory pile driving and mechanic dismantling for
the 120-dB re 1 [micro]Pa Level B harassment zone.
Monitoring of the pinniped and cetacean exclusion zones shall be
conducted by a minimum of three qualified NMFS-approved protected
species observers (PSOs). Observations will be made using high-quality
binoculars (e.g., Zeiss, 10 x 42 power). PSOs will be equipped with
radios or cell phones for maintaining contact with other observers and
CALTRANS engineers, and range finders to determine distance to marine
mammals, boats, buoys, and construction equipment.
Data on all observations will be recorded and will include the
following information:
(1) Location of sighting;
(2) Species;
(3) Number of individuals;
(4) Number of calves present;
(5) Duration of sighting;
(6) Behavior of marine animals sighted;
(7) Direction of travel;
(8) When in relation to construction activities did the sighting
occur (e.g., before, ``soft-start'', during, or after the pile driving
or removal).
The reactions of marine mammals will be recorded based on the
following classifications that are consistent with the Richmond Bridge
Harbor Seal survey methodology (for information on the Richmond Bridge
authorization, see 68 FR 66076, November 25, 2003): (1) No response,
(2) head alert (looks toward the source of disturbance), (3) approach
water (but not leave), and (4) flush (leaves haul-out site). The number
of marine mammals under each disturbance reaction will be recorded, as
well as the time when seals re-haul after a flush.
Hydroacoustic Monitoring
The purpose of the underwater sound monitoring during dismantling
of concrete foundations via mechanical means is to establish the
exclusion zones of 180 dB re 1 [micro]Pa (rms) for cetaceans and 190 dB
re 1 [micro]Pa (rms) for pinnipeds. Monitoring will occur during the
initial use of concrete dismantling equipment with the potential to
generate sound pressure levels in excess of 180 dB re 1 [micro]Pa
(rms). Monitoring will likely be conducted from construction barges
and/or boats. Measurements will be taken at various distances as needed
to determine the distance to the 180 and 190 dB re 1 [micro]Pa (rms)
contours.
The purpose of underwater sound monitoring during impact pile
driving will be to verify sound level estimates and confirm that sound
levels do not equal or exceed 180 dB re 1 [micro]Pa (rms).
Reporting
CALTRANS will notify NMFS prior to the initiation of the pile
driving and dismantling activities for the removal of the existing east
span. NMFS will be informed of the initial sound pressure level
measurements for both pile driving and foundation dismantling
activities, including the final exclusion zone and Level B harassment
zone radii established for impact and vibratory pile driving and marine
foundation dismantling activities.
Monitoring reports will be posted on the SFOBB Project's biological
mitigation Web site (www.biomitigation.org) on a weekly basis if in-
water construction activities are conducted. Marine mammal monitoring
reports will include species and numbers of marine mammals observed,
time and location of observation and behavior of the animal. In
addition, the reports will include an estimate of the number and
species of marine mammals that may have been harassed as a result of
activities.
In addition, CALTRANS will provide NMFS with a draft final report
within 90 days after the expiration of the IHA. This report should
detail the monitoring protocol, summarize the data recorded during
monitoring, and estimate the number of marine mammals that may have
been harassed due to pile driving. If no comments are received from
NMFS within 30 days, the draft final report will constitute the final
report. If comments are received, a final report must be submitted
within 30 days after receipt of comments.
Marine Mammal Monitoring Report From Previous IHA
As mentioned above, marine mammal monitoring during CALTRANS' pile
driving activities and weekly marine mammal observation memorandums
(CALTRANS 2007; 2010) indicate that only a small number of harbor seals
(a total of 16 individuals since 2006) and 1 California sea lion (a
total of 1 individual in 2009) were observed within ZOIs that could
result in behavioral harassment. However, the reports state that none
of the animals were observed as been startled by the exposure, which
could be an indication that these animals were habituated to human
activities in San Francisco Bay. In addition, no harbor porpoise or
gray whales were observed during pile driving activities associated to
CALTRANS' SF-OBB construction work.
Estimated Take by Incidental Harassment
Marine mammal take estimates are based on marine mammal monitoring
reports and marine mammal observations made during pile driving
activities associated with the SF-OBB construction work authorized
under prior IHAs. For pile driving activities conducted in 2006, 5
harbor seals and no other marine mammals were detected within the
isopleths of 160 dB (rms) re 1 [micro]Pa during impact pile driving
where air bubble curtains were deployed for mitigation measures (radius
of zone of influence (ZOI) at 500 m) (CALTRANS 2007). For pile driving
activities conducted in the 2008 and 2009 seasons, CALTRANS monitored a
much larger ZOI of 120 dB (rms) re 1 [micro]Pa as a result of vibratory
pile driving. A total of 11 harbor seals and 1 California sea lion were
observed entering the 120 dB (rms) re 1 [micro]Pa ZOI (CALTRANS).
However, despite the ZOI being monitored extended to 1,900 m for the
120 dB isopleths, CALTRANS did not specify which pile driving
activities conducted in 2008 and 2009 used an impact hammer and which
ones used a vibratory hammer. Therefore, at least some of these animals
were not exposed to received level above 160 dB (rms) re [micro]Pa, and
thus should not be considered as ``taken'' under the MMPA. No harbor
porpoise or gray whales were observed during pile driving activities
associated to CALTRANS' SF-OBB construction work (CALTRANS 2007; 2010).
Based on these results, and accounting for a certain level of
uncertainty regarding the next phase of construction (which will
include dismantling of the existing bridge by mechanical means), NMFS
concludes that at maximum 50 harbor seals, 10 California sea lions, 10
harbor porpoises, and 5 gray whales could be exposed to noise levels
that could cause Level B harassment as a result of the CALTRAN' SF-OBB
construction activities.
Negligible Impact and Small Numbers Analyses and Determinations
Pursuant to NMFS' regulations implementing the MMPA, an applicant
is required to estimate the number of animals that will be ``taken'' by
the specified activities (i.e., takes by
[[Page 2377]]
harassment only, or takes by harassment, injury, and/or death). This
estimate informs the analysis that NMFS must perform to determine
whether the activity will have a ``negligible impact'' on the species
or stock. Level B (behavioral) harassment occurs at the level of the
individual(s) and does not assume any resulting population-level
consequences, though there are known avenues through which behavioral
disturbance of individuals can result in population-level effects. 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 Level B harassment 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 behavioral harassment, NMFS
considers other factors, such as the likely nature of any responses
(their intensity, duration, etc.), the context of any responses
(critical reproductive time or location, migration, etc.), as well as
the number and nature of estimated Level A takes, the number of
estimated mortalities, and effects on habitat.
The CALTRANS' specified activities have been described based on
best estimates of the planned SF-OBB construction project within the
proposed project area. Some of the noises that would be generated as a
result of the proposed bridge construction and dismantling project,
such as impact pile driving, are high intensity. However, the in-water
pile driving for the piles would use small hammers and/or vibratory
pile driving methods, coupled with noise attenuation mechanism such as
air bubble curtains for impact pile driving, therefore the resulting
exclusion zones for potential TS are expected to be extremely small (<
35 m) from the hammer. In addition, the source levels from vibratory
pile driving are expected to be below the TS onset threshold.
Therefore, NMFS does not expect that any animals would receive Level A
(including injury) harassment or Level B harassment in the form of TTS
from being exposed to in-water pile driving associated with SF-OBB
construction project.
Based on marine mammal monitoring reports under previous IHAs, only
16 harbor seals and 1 California sea lion were observed within the 120
dB (in 2008 and 2009) or 160 dB (in 2006) ZOIs during in-water pile
driving since 2006. NMFS estimates that up to 50 harbor seals, 10
California sea lions, 10 harbor porpoises, and 5 gray whales could be
exposed to received levels above 120 dB (rms) during vibratory pile
driving or 160 dB (rms) during impact pile driving for the next season
of construction activities due to the large numbers of piles to be
driven and the extended zones of influence from vibratory pile driving.
These are small numbers, representing 0.15% of the California stock of
harbor seal population (estimated at 34,233; Carretta et al. 2010),
0.00% of the U.S. stock of California sea lion population (estimated at
238,000; Carretta et al. 2010), 0.10% of the San Francisco-Russian
River stock of harbor porpoise population (estimated at 9,181; Carretta
et al. 2010), and 0.05% of the Eastern North Pacific stock of gray
whale population (Allen and Angliss 2010).
Animals exposed to construction noise associated with the SF-OBB
construction work would be limited to Level B behavioral harassment
only, i.e., the exposure of received levels for impulse noise between
160 and 180 dB (rms) re 1 [mu]Pa (from impact pile driving) and for
non-impulse noise between 120 and 180 dB (rms) re 1 [mu]Pa (from
vibratory pile driving). In addition, the potential behavioral
responses from exposed animals are expected to be localized and short
in duration.
These low intensity, localized, and short-term noise exposures
(i.e., 160 dB re 1 [mu]Pa (rms) from impulse sources and 120 dB re 1
[mu]Pa (rms) from non-impulse sources), are expected to cause brief
startle reactions or short-term behavioral modification by the animals.
These brief reactions and behavioral changes are expected to disappear
when the exposures cease. Therefore, these levels of received
underwater construction noise from the proposed SF-OBB construction
project are not expected to affect marine mammal annual rates of
recruitment or survival. The maximum estimated 160 dB isopleths from
impact pile driving is 500 m from the pile, and the estimated 120 dB
maximum isopleths from vibratory pile driving is approximately 2,000 m
from the pile. There is no pinniped haul-out area in the vicinity of
the pile driving sites.
For the reasons discussed in this document, NMFS has determined
that the impact of in-water pile driving associated with construction
of the SF-OBB would result, at worst, in the Level B harassment of
small numbers of California sea lions, Pacific harbor seals, harbor
porpoises, and potentially gray whales that inhabit or visit SFB in
general and the vicinity of the SF-OBB in particular. While behavioral
modifications, including temporarily vacating the area around the
construction site, may be made by these species to avoid the resultant
visual and acoustic disturbance, the availability of alternate areas
within SFB and haul-out sites (including pupping sites) and feeding
areas within the Bay has led NMFS to determine that this action will
have a negligible impact on California sea lion, Pacific harbor seal,
harbor porpoise, and gray whale populations along the California coast.
In addition, no take by Level A harassment (injury) or death is
anticipated and harassment takes should be at the lowest level
practicable due to incorporation of the mitigation measures mentioned
previously in this document.
National Environmental Policy Act (NEPA)
NMFS prepared an Environmental Assessment (EA) for the take of
marine mammals incidental to construction of the East Span of the SF-
OBB and made a Finding of No Significant Impact (FONSI) on November 4,
2003. Due to the modification of part of the construction project and
the mitigation measures, NMFS reviewed additional information from
CALTRANS regarding empirical measurements of pile driving noises for
the smaller temporary piles without an air bubble curtain system and
the use of vibratory pile driving. NMFS prepared a Supplemental
Environmental Assessment (SEA) and analyzed the potential impacts to
marine mammals that would result from the modification of the action. A
Finding of No Significant Impact (FONSI) was signed on August 5, 2009.
A copy of the SEA and FONSI is available upon request (see ADDRESSES).
Endangered Species Act (ESA)
NMFS has determined that issuance of the IHA will have no effect on
listed marine mammals, as none are known to occur in the action area.
Authorization
NMFS has issued an IHA to CALTRANS for the potential harassment of
small numbers of harbor seals, California sea lions, harbor porpoises,
and gray whales incidental to construction of a replacement bridge for
the East Span of the San Francisco-Oakland Bay Bridge in California,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated.
Dated: January 7, 2013.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2013-00381 Filed 1-10-13; 8:45 am]
BILLING CODE 3510-22-P