Taking of Marine Mammals Incidental to Specified Activities; San Francisco-Oakland Bay Bridge Pier E3 Demolition via Controlled Implosion, 44060-44076 [2015-18178]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 80, Number 142 (Friday, July 24, 2015)]
[Notices]
[Pages 44060-44076]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-18178]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XE030


Taking of Marine Mammals Incidental to Specified Activities; San 
Francisco-Oakland Bay Bridge Pier E3 Demolition via Controlled 
Implosion

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments and information.

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SUMMARY: NMFS has received a request from the California Department of 
Transportation (CALTRANS) for an authorization to take small numbers of 
four species of marine mammals, by Level B harassment, incidental to 
proposed San Francisco-Oakland Bay Bridge (SFOBB) Pier E3 demolition 
via controlled implosion in San Francisco Bay (SFB or Bay). Pursuant to 
the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on 
its proposal to issue an authorization to CALTRANS to incidentally 
take, by harassment, small numbers of marine mammals for its proposed 
controlled implosion.

DATES: Comments and information must be received no later than August 
24, 2015.

ADDRESSES: Comments on the application should be addressed to Jolie 
Harrison, Chief, Permits and Conservation Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910. The mailbox address for providing email 
comments is itp.guan@noaa.gov. NMFS is not responsible for email 
comments sent to addresses other than the one provided here. Comments 
sent via email, including all attachments, must not exceed a 25-
megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information 
(for example, name, address, etc.) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    A copy of the application may be obtained by writing to the address 
specified above or visiting the internet

[[Page 44061]]

at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited 
in this notice may also be viewed, by appointment, during regular 
business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected 
Resources, NMFS, (301) 427-8401.

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, 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.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the U.S. can apply for a one-year authorization to 
incidentally take small numbers of marine mammals by harassment, 
provided that there is no potential for serious injury or mortality to 
result from the activity. 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 marine mammals. Within 45 days of the close of 
the comment period, NMFS must either issue or deny the authorization.

Summary of Request

    On March 3, 2015, CALTRANS submitted a request to NMFS for the 
potential harassment of a small number of marine mammals incidental to 
the dismantling of Pier E3 of the East Span of the original SFOBB in 
SFB, California, in fall 2015. CALTRANS is proposing to remove the Pier 
E3 via highly controlled implosion with detonations. On April 16, 2015, 
CALTRANS submitted a revision of its request with an inclusion of a 
test implosion before the bridge demolition. NMFS determined that the 
IHA application was complete on May 1, 2015. NMFS is proposing to 
authorize the Level B harassment of Pacific harbor seal, California sea 
lion, northern elephant seal, and harbor porpoise.

Description of the Specified Activity

Overview

    CALTRANS proposes removal of Pier E3 of the original SFOBB by use 
of controlled charges to implode the pier into its open cellular 
chambers below mudline. A Blast Attenuation System (BAS) will be used 
to minimize impacts to biological resources in the Bay. Given the 
complexity of removing the deep water caissons, CALTRANS is proposing 
the Demonstration Project to evaluate in-water controlled implosion 
techniques for the removal of marine foundations. CALTRANS' goal is to 
achieve a safe and efficient method for removing submerged foundations 
while avoiding and minimizing impacts to the Bay and natural 
communities and species within the project area.
    The Demonstration Project expects to reduce environmental impacts 
as compared to currently permitted conventional dismantling methods 
which would employ large cofferdams with extensive amounts of 
associated pile driving and dewatering. The use of controlled charges 
is expected to greatly reduce in-water work periods and shorten the 
overall duration of marine foundation removal.

Dates and Duration

    The controlled implosion and the pre-demolition test implosion are 
expected to occur in November 2015. Both pre-demolition implosion and 
the Pier E3 demolition via controlled implosion would last for about 5 
seconds each. The IHA is proposed to be valid between October 1 and 
December 30, 2015, per discussion between CALTRANS and NMFS.

Specified Geographic Region

    The location of the Pier E3 controlled implosion would occur within 
the Bay in the area around the east span of the SFOBB between Yerba 
Buena Island (YBI) and Oakland (Figure 16 of CALTRANS IHA application).

Detailed Description of CALTRANS Pier E3 Controlled Implosion

    CALTRANS proposes to remove Pier E3 of the original SFOBB by 
implosion using highly controlled charges. The mean of using controlled 
implosion is proposed as an alternate method to the original permitted 
mechanical methods for dismantling Pier E3, as it is expected to result 
in fewer in-water work days, have fewer effects on aquatic resources of 
the Bay, and require a shorter time frame for completion.
    In addition, to ensure that the Blast Attenuation System (BAS) for 
mitigation and the passive acoustic monitoring (PAM) for monitoring 
work properly during the implosion, CALTRANS is proposing a pre-
implosion test charge using a small detonation three or four days 
before the actual SFOBB implosion. Detailed descriptions of CALTRANS' 
implosion activities are provided below.

Drilling Boreholes

    Once the pier has been dismantled to the mechanical dismantling 
elevation, access platforms will be installed to support the drilling 
equipment while exposing the top of the interior cells and outside 
walls. Boreholes will be drilled on the inner cell walls and exterior 
walls of the pier for charge placement. An overhanging template system 
will be installed to guide the drill below the waterline. Divers will 
be required to cut notches to guide the drilling of underwater 
boreholes. No marine mammal is expected to be affected from borehole 
drilling activities.

Blast Attenuation System Installation and Deployment

    To minimize the potential impacts from shockwave generated from the 
bridge implosion, a Blast Attenuation System (BAS). The BAS to be used 
at Pier E3 is a modular system of pipe manifold frames that will be fed 
by 1,400-1,600 cubic feet per minute (cfm) air compressors to create a 
curtain of air bubbles around the entire pier during the controlled 
implosion. Proposed BAS design details and specifications are provided 
in Appendix B of CALTRANS' IHA application. Each BAS frame will be 
lowered to the bottom of the Bay by a barge mounted crane and 
positioned into place. Divers will be used to assist frame placement 
and to connect air hoses to the frames.
    Based on location around the pier, the BAS frame elements will be 
situated from approximately 25 ft (7.6 m) to 40 ft (12 m) from the 
outside edge of Pier E3. The frames will be situated to contiguously 
surround the pier; frame

[[Page 44062]]

ends will overlap to ensure no break in the BAS when operational. Each 
frame will be weighted to negative buoyancy for activation. Each BAS 
frame will be fed by an individual compressor mounted on a barge. This 
will require 14 compressors on approximately 14 flexi-float barges 
situated around the pier. Each barge will be temporarily anchored to 
maintain their position around the pier. Compressors will be turned on 
and each section of the BAS will be tested for uniform air flow prior 
to the controlled implosion. Once the controlled implosion event has 
been completed, the contractor will demobilize the BAS and all 
associated equipment. Compressors will provide enough pressure to 
achieve a minimal air volume fraction of 3-4%, consistent with the 
successful use of BAS systems in past controlled blasting activities 
(Kiewit-Mass, pers. comm. in: CALTRANS 2015).
    System performance is anticipated to provide approximately 80% 
attenuation, or better, based on past experience with similar systems 
during controlled blasting. Previous implosions using similar BAS 
systems in Ontario, Canada showed 85%-95% attenuation, in Vancouver, 
Canada showed 84%-88% attenuation, and in Manitoba, Canada showed 90-
98% attenuation (Kiewit-Mason, pers. comm. in: CALTRANS 2015).
    The installation of the BAS is not expected to effects marine 
mammals in the project vicinity.

Pre-Implosion Test Charge

    Acoustically capturing the implosion is critical for the 
determination of whether or not this technique can be used for future 
piers. A key factor in accurately capturing hydroacoustic information 
is to ensure triggering of the data acquisition/recording instrument 
used for high speed recording during near-field and far-field 
monitoring of the implosion. To this end, the pressure-time signature 
of a blast cannot be duplicated except with another blast. As such, 
release of a small test charge before the actual implosion is required 
to validate that all equipment is functional and to set the triggering 
parameters accurately for the implosion.
    Release of the test charge will occur at least three to four days 
prior to the actual implosion and after the BAS is in place and 
functional. The BAS will be in operation during the test. The test will 
use a charge weight of 18 grain (0.0025 lbs) or less. The charge will 
be placed along one of the longer faces of the Pier and inside the BAS 
while it is operating. The charge will be positioned near the center of 
the wider face of the pier to shield the areas on the opposite side as 
much as possible from sound. The charge will be placed approximately 
halfway between the face of the pier and the BAS. Note, the BAS may be 
located anywhere from 25 to 45 ft from the face of the Pier. Monitoring 
inside the BAS will be done at a distance of 20 to 30 feet from the 
blast. Outside the BAS, monitoring will occur at a distance of 100 feet 
from the charge.
    Due to the small amount of charges to be used the test, no marine 
mammal is expected to be effected.

Controlled Implosion Dismantling of Remaining Pier

    The controlled implosion event is scheduled to take place in 
November of 2015. Prior to the event, the bore holes in Pier E3 will be 
loaded with charges, as described in the Blast Plan (Appendix A of 
CALTRANS IHA application).
    Individual cartridge charges, versus pump-able liquid blasting 
agents, have been chosen to provide greater accuracy in estimating the 
individual and total charge weights. Charges will be transported by 
boat to Pier E3. Security will be required for transporting, handling 
and processing of the charges.
    Boreholes vary in diameter and depth and have been optimized for 
charge efficiency. Individual and total charge weight loads are 
provided in the Blast Plan. Charges are arranged in different levels 
(decks) separated in the boreholes by stemming. Stemming is the 
insertion of inert materials, like sand or gravel, to insulate and 
retain charges in an enclosed space. Stemming allows for more efficient 
transfer of energy into the structural concrete for fracture, and 
further reduces the release of potential energy into the adjacent water 
column.
    The blast event will consist of a total of 588 individual delays of 
varying charge weight; the largest is 35 pounds/delay and the smallest 
is 21 pounds/delay. The blasting sequence is rather complex. On the 
full height walls, 30 pound weights will be used for the portion below 
mud line, 35 pound weights will be used in the lower structure 
immediately above mud line, 29.6 pounds in the midstructure, and 21 
pounds in the upper structure. Blasts will start in several interior 
webs of the southern portion of the structure followed by the outer 
walls of the south side. The blasts in the inner walls will occur just 
prior to the adjacent outer walls. The interior first, exterior second 
blast sequence will continue across the structure moving from south to 
north. The time for the 588 detonations is 5.3 seconds with a minimum 
delay time of 9 milliseconds (ms) between detonations. As the blasting 
progresses, locations to east, north, and west of the pier will be 
shielded from the blasting on the interior of the structure from the 
still-standing exterior walls of the pier. However, towards the 
conclusion of the blast, each direction will experience blasts from the 
outer walls that are not shielded.

Description of Marine Mammals in the Area of the Specified Activity

    The marine mammal species under NMFS jurisdiction most likely to 
occur in the proposed construction area include Pacific harbor seal 
(Phoca vitulina richardsi), northern elephant seal (Mirounga 
angustirostris), California sea lion (Zalophus californianus), and 
harbor porpoise (Phocoena phocoena).

                    Table 1--Marine Mammal Species Potentially Present in Region of Activity
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              Species                      ESA status              MMPA status                Occurrence
----------------------------------------------------------------------------------------------------------------
Harbor Seal........................  Not listed............  Non-depleted..........  Frequent.
California Sea Lion................  Not listed............  Non-depleted..........  Occasional.
Northern Elephant Seal.............  Not listed............  Non-depleted..........  Occasional.
Harbor Porpoise....................  Not listed............  Non-depleted..........  Rare.
----------------------------------------------------------------------------------------------------------------

    General information on the marine mammal species found in the San 
Francisco Bay can be found in Caretta et al. (2014), which is available 
at the following URL: https://www.nmfs.noaa.gov/pr/sars/pdf/po2013.pdf. 
Refer to that document for information on these species. A list of 
marine mammals in the vicinity of the action and their status are 
provided in Table 1. Specific information concerning these species in 
the vicinity

[[Page 44063]]

of the proposed action area is provided in detail in the CALTRANS's IHA 
application.

Potential Effects of the Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that the 
types of stressors associated with the specified activity (e.g., pile 
removal and pile driving) have been observed to impact marine mammals. 
This discussion may also include reactions that we consider to rise to 
the level of a take and those that we do not consider to rise to the 
level of a take (for example, with acoustics, we may include a 
discussion of studies that showed animals not reacting at all to sound 
or exhibiting barely measurable avoidance). This section is intended as 
a background of potential effects and does not consider either the 
specific manner in which this activity will be carried out or the 
mitigation that will be implemented, and how either of those will shape 
the anticipated impacts from this specific activity. The ``Estimated 
Take by Incidental Harassment'' section later in this document will 
include a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The ``Analysis and Preliminary 
Determinations'' section will include the analysis of how this specific 
activity will impact marine mammals and will consider the content of 
this section, the ``Estimated Take by Incidental Harassment'' section, 
the ``Proposed Mitigation'' section, and the ``Anticipated Effects on 
Marine Mammal Habitat'' section to draw conclusions regarding the 
likely impacts of this activity on the reproductive success or 
survivorship of individuals and from that on the affected marine mammal 
populations or stocks.
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Based 
on available behavioral data, audiograms have been derived using 
auditory evoked potentials, anatomical modeling, and other data, 
Southall et al. (2007) designate ``functional hearing groups'' for 
marine mammals and estimate the lower and upper frequencies of 
functional hearing of the groups. The functional groups and the 
associated frequencies are indicated below (though animals are less 
sensitive to sounds at the outer edge of their functional range and 
most sensitive to sounds of frequencies within a smaller range 
somewhere in the middle of their functional hearing range):
     Low frequency cetaceans (13 species of mysticetes): 
Functional hearing is estimated to occur between approximately 7 Hz and 
25 kHz;
     Mid-frequency cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
     High frequency cetaceans (eight species of true porpoises, 
six species of river dolphins, Kogia, the franciscana, and four species 
of cephalorhynchids): Functional hearing is estimated to occur between 
approximately 200 Hz and 180 kHz;
     Phocid pinnipeds in Water: Functional hearing is estimated 
to occur between approximately 75 Hz and 100 kHz; and
     Otariid pinnipeds in Water: Functional hearing is 
estimated to occur between approximately 100 Hz and 40 kHz.
    As mentioned previously in this document, four marine mammal 
species (one cetacean and three pinniped species) are likely to occur 
in the proposed Pier E3 controlled implosion area. The only one 
cetacean species (harbor porpoise) in the area is classified as high-
frequency cetaceans, 2 species of pinniped are phocid (Pacific harbor 
seal and norther elephant seal), and 1 species of pinniped is otariid 
(California sea lion). A species' functional hearing group is a 
consideration when we analyze the effects of exposure to sound on 
marine mammals.
    We expect that an intense impulse from the proposed Pier E3 
controlled implosion would have the potential to impact marine mammals 
in the vicinity. The majority of impacts would be startle behavioral 
and temporary behavioral modification from marine mammals. However, a 
few individuals of animals could be exposed to sound levels that would 
cause temporal hearing threshold shift (TTS).

Impacts From Underwater Detonations in Free Field Environment at Close 
Range

    The underwater explosion would send a shock wave and blast noise 
through the water, release gaseous by-products, create an oscillating 
bubble, and cause a plume of water to shoot up from the water surface. 
The shock wave and blast noise are of most concern to marine animals. 
The effects of an underwater explosion on a marine mammal depends on 
many factors, including the size, type, and depth of both the animal 
and the explosive charge; the depth of the water column; and the 
standoff distance between the charge and the animal, as well as the 
sound propagation properties of the environment. Potential impacts can 
range from brief effects (such as behavioral disturbance), tactile 
perception, physical discomfort, slight injury of the internal organs 
and the auditory system, to death of the animal (Yelverton et al. 1973; 
DoN, 2001). Non-lethal injury includes slight injury to internal organs 
and the auditory system; however, delayed lethality can be a result of 
individual or cumulative sublethal injuries (DoN, 2001). Immediate 
lethal injury would be a result of massive combined trauma to internal 
organs as a direct result of proximity to the point of detonation (DoN, 
2001). Generally, the higher the level of impulse and pressure level 
exposure, the more severe the impact to an individual.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different density. Different velocities are imparted 
to tissues of different densities, and this can lead to their physical 
disruption. Blast effects are greatest at the gas-liquid interface 
(Landsberg 2000). Gas-containing organs, particularly the lungs and 
gastrointestinal tract, are especially susceptible (Goertner 1982; Hill 
1978; Yelverton et al. 1973). In addition, gas-containing organs 
including the nasal sacs, larynx, pharynx, trachea, and lungs may be 
damaged by compression/expansion caused by the oscillations of the 
blast gas bubble. Intestinal walls can bruise or rupture, with 
subsequent hemorrhage and escape of gut contents into the body cavity. 
Less severe gastrointestinal tract injuries include contusions, 
petechiae (small red or purple spots caused by bleeding in the skin), 
and slight hemorrhaging (Yelverton et al. 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten 2000). Sound-related damage 
associated with blast noise can be theoretically distinct from injury 
from the shock wave, particularly farther from the explosion. If an 
animal is able to hear a noise, at some level it can damage its hearing 
by causing decreased sensitivity (Ketten 1995). Sound-related trauma 
can be lethal or sublethal. Lethal impacts are those that result in 
immediate death or serious debilitation in or near an intense source 
and are not, technically, pure acoustic trauma (Ketten 1995). Sublethal 
impacts include hearing loss, which is caused by exposures to 
perceptible sounds. Severe damage (from the shock wave) to the ears 
includes tympanic

[[Page 44064]]

membrane rupture, fracture of the ossicles, damage to the cochlea, 
hemorrhage, and cerebrospinal fluid leakage into the middle ear. 
Moderate injury implies partial hearing loss due to tympanic membrane 
rupture and blood in the middle ear. Permanent hearing loss also can 
occur when the hair cells are damaged by one very loud event, as well 
as by prolonged exposure to a loud noise or chronic exposure to noise. 
The level of impact from blasts depends on both an animal's location 
and, at outer zones, on its sensitivity to the residual noise (Ketten, 
1995).

Confined Detonation and Associated Level B Harassment

    However, the above discussion concerning underwater explosion only 
pertains to open water detonation in a free field. CALTRANS' Pier E3 
demolition project using controlled implosion uses a confined 
detonation method, meaning that the charges would be placed within the 
structure. Therefore, most energy from the explosive shock wave would 
be absorbed through the destruction of the structure itself, and would 
not propagate through the open water. Measurements and modeling from 
confined underwater detonation for structure removal showed that energy 
from shock waves and noise impulses were greatly reduced in the water 
column (Hempen et al. 2007). Therefore, with monitoring and mitigation 
measures discussed above, CALTRANS Pier E3 controlled implosion is not 
likely to have the injury or mortality effects on marine mammals in the 
project vicinity. Instead, NMFS considers that CALTRANS' proposed Pier 
E3 controlled implosion in the San Francisco Bay is most like to cause 
Level B behavioral harassment and maybe TTS in a few individual of 
marine mammals, as discussed below.
    Changes in marine mammal behavior are expected to result from an 
acute stress response. This expectation is based on the idea that some 
sort of physiological trigger must exist to change any behavior that is 
already being performed. The exception to this rule is the case of 
auditory masking, which is not likely since the CALTRANS' controlled 
implosion is only one short of sequential detonations that last for 
approximately 5 seconds.
    Numerous behavioral changes can occur as a result of stress 
response. For each potential behavioral change, the magnitude in the 
change and the severity of the response needs to be estimated. Certain 
conditions, such as stampeding (i.e., flight response) or a response to 
a predator, might have a probability of resulting in injury. For 
example, a flight response, if significant enough, could produce a 
stranding event. Each disruption to a natural behavioral pattern (e.g., 
breeding or nursing) may need to be classified as Level B harassment. 
All behavioral disruptions have the potential to contribute to the 
allostatic load. This secondary potential is signified by the feedback 
from the collective behaviors to allostatic loading.
    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 will have reduced fitness in 
survival and reproduction, either permanently or temporarily. Repeated 
noise exposure that leads to TTS could cause PTS.
    Experiments on a bottlenose dolphin and beluga whale 
(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 re 1 [mu]Pa (p-p), 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 in the aforementioned 
experiment (Finneran et al. 2002).

Potential Effects on Marine Mammal Habitat

    The proposed Pier E3 demolition using controlled implosion will not 
result in any permanent impact on habitats used by marine mammals, and 
potentially short-term to minimum impact to the food sources such as 
forage fish. There are no known haul-out sites, foraging hotspots, or 
other ocean bottom structures of significant biological importance to 
harbor seals, northern elephant seals, California sea lions, or harbor 
porpoises within San Francisco Bay. Therefore, the main impact 
associated with the activity will be the removal of an existing bridge 
structure.
    Fish that are located in the water column, in close proximity to 
the source of the controlled implosion could be injured, killed, or 
disturbed by the impulsive sound and could leave the area temporarily. 
Continental Shelf Associates, Inc. (2002) summarized a few studies 
conducted to determine effects associated with removal of offshore 
structures (e.g., oil rigs) in the Gulf of Mexico. Their findings 
revealed that at very close range, underwater explosions are lethal to 
most fish species regardless of size, shape, or internal anatomy. In 
most situations, cause of death in fish has been massive organ and 
tissue damage and internal bleeding. At longer range, species with gas-
filled swimbladders (e.g., snapper, cod, and striped bass) are more 
susceptible than those without swimbladders (e.g., flounders, eels).
    Studies also suggest that larger fish are generally less 
susceptible to death or injury than small fish. Moreover, elongated 
forms that are round in cross section are less at risk than deep-bodied 
forms. Orientation of fish relative to the shock wave may also affect 
the extent of injury. Open water pelagic fish (e.g., mackerel) seem to 
be less affected than reef fishes. The results of most studies are 
dependent upon specific biological, environmental, explosive, and data 
recording factors.
    The huge variation in fish populations, including numbers, species, 
sizes, and orientation and range from the detonation point, makes it 
very difficult to accurately predict mortalities at any specific site 
of detonation. Most fish species experience a large number of natural 
mortalities, especially during early life-stages, and any small level 
of mortality caused by the CALTRANS' one time controlled implosion will 
likely be insignificant to the population as a whole.

Proposed Mitigation Measures

    In order to issue an incidental take authorization 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 adverse 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.

[[Page 44065]]

    For CALTRANS's proposed Pier E3 controlled implosion, CALTRANS 
worked with NMFS and proposed the following mitigation measures to 
minimize the potential impacts to marine mammals in the project 
vicinity. The primary purposes of these mitigation measures are to 
minimize sound levels from the activities, to monitor marine mammals 
within designated exclusion zones and zones of influence (ZOI). 
Specific proposed mitigation measures are described below.

Time Restriction

    Implosion of Pier E3 would only be conducted during daylight hours 
and with enough time for pre and post implosion monitoring, and with 
good visibility when the largest exclusion zone can be visually 
monitored.

Installation of Blast Attenuation System (BAS)

    Prior to the Pier E3 demolition, CALTRANS should install a Blast 
Attenuation System (BAS) as described above to reduce the shockwave 
from the implosion.

Establishment of Level A Exclusion Zone

    Due to the different hearing sensitivities among different taxa of 
marine mammals, NMFS has established a series of take thresholds from 
underwater explosions for marine mammals belonging to different 
functional hearing groups (Table 2). Under these criteria, marine 
mammals from different taxa will have different impact zones (exclusion 
zones and zones of influence).
    CALTRANS will establish an exclusion zone for both the mortality 
and Level A harassment zone (permanent hearing threshold shift or PTS, 
GI track injury, and slight lung injury) using the largest radius 
estimated harbor and northern elephant seals. Estimates are that the 
isopleth for PTS would extend out to a radius of 1,160 ft (354 m) for 
harbor and northern elephant seals to 5,800 ft (1,768 m) for harbor 
porpoise; covering the entire areas for both Level A harassment and 
mortality. As harbor porpoises are unlikely to be in the area in 
November, the exclusion zone boundaries would be set around the 
calculated distance to Level A harassment for harbor and northern 
elephant seals. However, real-time acoustic monitoring (i.e., active 
listening for vocalizations with hydrophones) also will be utilized to 
provide an additional level of confidence that harbor porpoises are not 
in the affected area.

                   Table 2--NMFS Acoustic Criteria for Marine Mammals in the SFOBB Pier E3 Demolition Area from Underwater Implosions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Level B harassment               Level A               Serious injury
                                                ------------------------------------    harassment    ----------------------------------
            Group                   Species                                         ------------------     Gastro-                          Mortality
                                                    Behavioral            TTS                             intestinal          Lung
                                                                                            PTS             tract
--------------------------------------------------------------------------------------------------------------------------------------------------------
High-freq cetacean...........  Harbor porpoise.  141 dB SEL......  146 dB SEL or     161 dB SEL or     237 dB SPL or    39.1M[frac13]    91.4M[frac13]
                                                                    195 dB SPLpk.     201 dB SPLpk.     104 psi.         (1+[D/           (1+[D/
                                                                                                                         10.081])[frac1   10.081])[frac1
                                                                                                                         2].              2]
                                                                                                                        Pa-sec.........  Pa-sec
                                                                                                                        where: M = mass  where: M = mass
                                                                                                                         of the animals   of the animals
                                                                                                                         in kg.           in kg
                                                                                                                        D = depth of     D = depth of
                                                                                                                         animal in m.     animal in m
Phocidae.....................  Harbor seal &     172 dB SEL......  177 dB SEL or     192 dB SEL or
                                northern                            212 dB SPLpk.     218 dB SPLpk.
                                elephant seal.
Otariidae....................  California sea    195 dB SEL......  200 dB SEL or     215 dB SEL or
                                lion.                               212 dBpk.         218 dB SPLpk.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: All dB values are referenced to 1 [micro]Pa. SPLpk = Peak sound pressure level; psi = pounds per square inch.

    Adherence to calculated distances to Level A harassment for 
pinnipeds indicates that the radius of the exclusion zone would be 
1,160 ft (354 m). The exclusion zone will be monitored by protected 
species observers (PSOs) and if any marine mammals are observed inside 
the exclusion, the implosion will be delayed until the animal leaves 
the area or at least 30 minutes have passed since the last observation 
of the marine mammal. Hearing group specific exclusion zone ranges are 
provided in Table 3.

Establishment of Level B Temporary Hearing Threshold Shift (TTS) Zone 
of Infulence:

    As shown in Table 1, for harbor and northern elephant seals, this 
will cover the area out to 212 dB peak SPL or 177 dB SEL, whichever 
extends out the furthest. Hydroacoustic modeling indicates this 
isopleth would extend out to 5,700 ft (1,737 m) from Pier E3. For 
harbor porpoises, this will cover the area out to 195 dB peak SPL or 
146 dB SEL, whichever extends out the furthest. Hydroacoustic modeling 
indicates this isopleth would extend out to 26,500 ft (8,077 m) from 
Pier E3. As discussed previously, the presence of harbor porpoises in 
this area is unlikely but monitoring (including real-time acoustic 
monitoring) will be employed to confirm their absence. For California 
sea lions, the distance to the Level B TTS zone of influence will cover 
the area out to 212 dB peak SPL or 200 dB SEL. This distance was 
calculated at 470 ft (143 m) from Pier E3, well within the exclusion 
zone previously described. Hearing group specific Level B TTS zone of 
influence ranges are provided in Table 3.

Establishment of Level B Behavioral Zone of Influence

[[Page 44066]]

[GRAPHIC] [TIFF OMITTED] TN24JY15.000

    As shown in Table 1, for harbor seals and northern elephant seals, 
this will cover the area out to 172 dB SEL. Hydroacoustic modeling 
indicates this isopleth would extend out to 9,700 ft (2,957 m) from 
Pier E3. For harbor porpoises, this will cover the area out to 141 dB 
SEL. Hydroacoustic modeling indicates this isopleth would extend out to 
44,500 ft (13,564 m) from Pier E3. As discussed previously, the 
presence of harbor porpoises in this area is unlikely but monitoring 
(including real-time acoustic monitoring) will be employed to confirm 
their absence. For California sea lions, the distance to the Level B 
behavioral harassment ZOI will cover the area out to 195 dB SEL. This 
distance was calculated at 800 ft (244 m) from Pier E3, well within the 
exclusion zone previously described. Hearing group specific Level B TTS 
zone of influence ranges are provided in Table 3.

Communication

    All PSOs will be equipped with mobile phones and a VHF radio as a 
backup. One person will be designated as the Lead PSO and will be in 
constant contact with the Resident Engineer on site and the blasting 
crew. The Lead PSO will coordinate marine mammal sightings with the 
other PSOs and the real time acoustic monitor. PSOs will contact the 
other PSOs when a sighting is made within the exclusion zone or near 
the exclusion zone so that the PSOs within overlapping areas of 
responsibility can continue to track the animal and the Lead PSO is 
aware of the animal. If it is within 30 minutes of blasting and an 
animal has entered the exclusion zone or is near it, the Lead PSO will 
notify the Resident Engineer and blasting crew. The Lead PSO will keep 
them informed of the disposition of the animal.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned
     The practicability of the measure for applicant 
implementation.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal).
    (2) A reduction in the numbers of marine mammals (total number or 
number at biologically important time or location) exposed to received 
levels of pile driving and pile removal or other activities expected to 
result in the take of marine mammals (this goal may

[[Page 44067]]

contribute to 1, above, or to reducing harassment takes only).
    (3) A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of pile driving and pile removal, or other 
activities expected to result in the take of marine mammals (this goal 
may contribute to 1, above, or to reducing harassment takes only).
    (4) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to received 
levels of pile driving, or other activities expected to result in the 
take of marine mammals (this goal may contribute to a, above, or to 
reducing the severity of harassment takes only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying special attention to the food base, activities that 
block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
    (6) For monitoring directly related to mitigation--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammals 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 incidental take authorization (ITA) 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 ITAs 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. CALTRANS submitted a marine mammal 
monitoring plan as part of the IHA application. It can be found at 
https://www.nmfs.noaa.gov/pr/permits/incidental.htm. The plan may be 
modified or supplemented based on comments or new information received 
from the public during the public comment period.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    (1) An increase in the probability of detecting marine mammals, 
both within the mitigation zone (thus allowing for more effective 
implementation of the mitigation) and in general to generate more data 
to contribute to the analyses mentioned below;
    (2) An increase in our understanding of how many marine mammals are 
likely to be exposed to levels of pile driving that we associate with 
specific adverse effects, such as behavioral harassment, TTS, or PTS;
    (3) An increase in our understanding of how marine mammals respond 
to stimuli expected to result in take and how anticipated adverse 
effects on individuals (in different ways and to varying degrees) may 
impact the population, species, or stock (specifically through effects 
on annual rates of recruitment or survival) through any of the 
following methods:
    [ssquf] Behavioral observations in the presence of stimuli compared 
to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information);
    [ssquf] Physiological measurements in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information);
    [ssquf] Distribution and/or abundance comparisons in times or areas 
with concentrated stimuli versus times or areas without stimuli;
    (4) An increased knowledge of the affected species; and
    (5) An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.

Proposed Monitoring Measures

    Monitoring for implosion impacts to marine mammals will be based on 
the SFOBB pile driving monitoring protocol. Pile driving has been 
conducted for the SFOBB construction project since 2000 with 
development of several NMFS-approved marine mammal monitoring plans 
(CALTRANS 2004; 2013). Most elements of these marine mammal monitoring 
plans are similar to what would be required for underwater implosions. 
These monitoring plans would include monitoring an exclusion zone and 
ZOIs for TTS and behavioral harassment described above. In addition, 
CALTRANS shall implement passive acoustic monitoring. All monitoring 
would be conducted by NMFS-approved PSOs.

(1) Protected Species Observers

    A minimum of 8-10 PSOs would be required during the Pier E3 
controlled implosion so that the exclusion zone, Level B Harassment TTS 
and Behavioral ZOIs, and surrounding area can be monitored. One PSO 
would be designated as the Lead PSO and would receive updates from 
other PSOs on the presence or absence of marine mammals within the 
exclusion zone and would notify the Blasting Supervisor of a cleared 
exclusion zone to the implosion.

(2) Monitoring Protocol

    PSOs shall be positioned near the edge of each of the thredhold 
criteria zones and shall utilize boats, barges, bridge piers and 
roadway, and sites on Yerba Buena Island and Treasure Island, as 
described in Figure 3 of the CALTRANS Marine Mammal Monitoring Plan. 
The Lead PSO shall be located with the Department Engineer and the 
Blasting Supervisor (or person that will be in charge of detonating the 
charges) during the implosion.
    The Lead PSO will be in contact with other PSOs and the acoustic 
monitors. As the time for the implosion approaches, any marine mammal 
sightings would be discussed between the Lead PSO, the Resident 
Engineer, and the Blasting Supervisor. If any marine mammals enter the 
exclusion zone within 30 minutes of blasting, the Lead PSO will notify 
the Resident Engineer and Blasting Supervisor that the implosion may 
need to be delayed. The Lead PSO will keep them informed of the 
disposition of the animal. If the animal remains in the exclusion zone, 
blasting will be delayed until it has left the exclusion zone. If the 
animal dives and is not seen again, blasting will be delayed at least 
30 minutes. Once the implosion has occurred, the PSOs will continue to 
monitor the area for at least 60 minutes.

(3) Post-Implosion Survey

    Although any injury or mortality from the implosion of Pier E3 is 
very unlikely, boat or shore surveys will be conducted for the three 
days following the event to determine if there are any injured or 
stranded marine mammals in the area. If an injured or dead animal is 
discovered during these surveys or by other means, the NMFS-designated 
stranding team will be contacted to pick up the animal. Veterinarians 
will treat the animal or conduct a necropsy to

[[Page 44068]]

attempt to determine if it stranded was a result of the Pier E3 
implosion.

(4) Monitoring Data Collection

    Each PSO will record their observation position, start and end 
times of observations, and weather conditions (sunny/cloudy, wind 
speed, fog, visibility). For each marine mammal sighting, the following 
will be recorded, if possible:

 Species
 Number of animals (with or without pup/calf)
 Age class (pup/calf, juvenile, adult)
 Identifying marks or color (scars, red pelage, damaged dorsal 
fin, etc.)
 Position relative to Pier E3 (distance and direction)
 Movement (direction and relative speed)
 Behavior (logging [resting at the surface], swimming, 
spyhopping [raising above the water
 surface to view the area], foraging, etc.)
 Duration of sighting or times of multiple sightings of the 
same individual

(5) Real Time Acoustic Monitoring for Harbor Porpoises

    While harbor porpoises are not expected to be within the CALTRANS' 
Pier E3 implosion Level B TTS ZOI (within 26,500 ft [8,077 ms]) in 
November, real time acoustic monitoring to confirm species absence is 
proposed as an avoidance measure in addition to active monitoring by 
trained visual PSOs. Harbor porpoises vocalize frequently with other 
animals within their group, and use echolocation to navigate and to 
locate prey. Therefore, as an additional monitoring tool, a real time 
acoustic monitoring system will be used to detect the presence or 
absence of harbor porpoises as a supplement to visual monitoring.
    The system would involve two bio-acousticians monitoring the site 
in real time, likely near the north end of Treasure Island as most 
harbor porpoises appear to pass through the area north of Treasure 
Island before heading south toward the East Span of the SFOBB. A 
calibrated hydrophone or towed array would be suspended from a boat 
and/or several sonobuoys (acoustic information is sent via telemetry to 
the acoustic boat) or a hydrophone moored offshore with a cable leading 
to a shore based acoustic station will be deployed outside of the 
monitoring area of Pier E3. All equipment will be calibrated and tested 
prior to the implosion to ensure functionality. This system would not 
be able to give an accurate distance to the animal but would either 
determine that no cetaceans are in the area or would provide a relative 
distance and direction so that PSOs could search for the cetaceans and 
determine if those animals have entered or may enter the Pier E3 
implosion area. The bio-acousticians would be in communication with the 
Lead PSO and would alert the crew to the presence of any cetacean 
approaching the monitoring area. It would also provide further 
confirmation that there are no cetaceans around Pier E3 in addition to 
the visual observations documenting no observations.

(6) Hydroacoustic Monitoring for Underwater Implosion

    The purpose of hydroacoustic monitoring during the controlled 
implosion of Pier E3 is twofold: (1) To evaluate distances to marine 
mammal impact noise criteria; and (2) to improve the prediction of 
underwater noise for assessing the impact of the demolition of the 
remaining piers through future controlled implosions.
    Monitoring of the implosion is specific to two regions around Pier 
E3 with unique methods, approaches, and plans for each of these 
regions. These regions include the ``near field'' and the ``far 
field''. For Pier E3, the near field will comprise measurements taken 
within 500 ft of the pier while the far field will comprise 
measurements taken at 500 feet and all greater distances.
    Measurements inside the BAS will be made with near and far field 
systems using PCB 138A01 transducers. At the 100-ft distance, the near 
field system will use another PCB 138A01 transducer while the far field 
system will use both a PCB 138A01 transducer and a Reson TC4013 
hydrophone. Prior to activating the BAS, ambient noise levels will be 
measured. While the BAS is operating and before the test implosion, 
background noise measurements will also be made. After the test 
implosion, the results will be evaluated to determine if any final 
adjustments are needed in the measurement systems prior to the Pier E3 
controlled implosion. Pressure signals will be analyzed for peak 
pressure and SEL values prior to the scheduled time of the Pire E3 
controlled implosion.

Proposed Reporting Measures

    CALTRANS would be required to submit a draft monitoring report 
within 90 days after completion of the construction work or the 
expiration of the IHA (if issued), whichever comes earlier. This draft 
report would detail the monitoring protocol, summarize the data 
recorded during monitoring, and estimate the number of marine mammals 
that may have been harassed. NMFS would have an opportunity to provide 
comments on the draft report within 30 days, and if NMFS has comments, 
CALTRANS would address the comments and submit a final report to NMFS 
within 30 days. If no comments are provided by NMFS after 30 days 
receiving the report, the draft report is considered to be final.

Marine Mammal Stranding Plan

    In addition, a stranding plan will be prepared in cooperation with 
the local NMFS-designated marine mammal stranding, rescue, and 
rehabilitation center. Although mitigation measures would likely 
prevent any injuries, preparations will be made in the unlikely event 
that marine mammals are injured. Elements of that plan would include 
the following:
    1. The stranding crew would prepare treatment areas at the NMFS-
designated facility for cetaceans or pinnipeds that may be injured from 
the implosion. Preparation would include equipment to treat lung 
injuries, auditory testing equipment, dry and wet caged areas to hold 
animals, and operating rooms if surgical procedures are necessary. 
Equipment to conduct auditory brainstem response hearing testing would 
be available to determine if any inner ear threshold shifts (TTS or 
PTS) have occurred (Thorson et al. 1999).
    2. A stranding crew and a veterinarian would be on call near the 
Pier E3 site at the time of the implosion to quickly recover any 
injured marine mammals, provide emergency veterinary care, stabilize 
the animal's condition, and transport individuals to the NMFS-
designated facility. If an injured or dead animal is found, NMFS (both 
the regional office and headquarters) will be notified immediately even 
if the animal appears to be sick or injured from other than blasting.
    3. Post-implosion surveys would be conducted immediately after the 
event and over the following three days to determine if there are any 
injured or dead marine mammals in the area.
    4. Any veterinarian procedures, euthanasia, rehabilitation 
decisions and time of release or disposition of the animal will be at 
the discretion of the NMFS-designated facility staff and the 
veterinarians treating the animals. Any necropsies to determine if the 
injuries or death of an animal was the result of the blast or other 
anthropogenic or natural causes will be conducted at the NMFS-
designated facility by the stranding crew and veterinarians. The 
results will be communicated to both CALTRANS and

[[Page 44069]]

to NMFS as soon as possible with a written report within a month.

Estimated Take by Incidental 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].
    Numbers of marine mammals within the Bay may be incidentally taken 
during demolition using controlled charges (impulse sound) related to 
the demolition of the original East Span of the SFOBB were calculated 
based on acoustic propagation models for each functional hearing group 
and the estimated density of each species in the project vicinity. 
Specifically, the takes estimates are calculated by multiplying the 
ensonified areas that are specific to each functional hearing group by 
the density of the marine mammal species.

Marine Mammal Density Estimates

    There are no systematic line transect surveys of marine mammals 
within San Francisco Bay, therefore, the in water densities of harbor 
seals, California sea lions, and harbor porpoises were calculated from 
14 years of observations during monitoring for the SFOBB construction 
and demolition. During the 210 days of monitoring (including 15 days of 
baseline monitoring in 2003), 657 harbor seals, 69 California sea lions 
and three harbor porpoises were observed within the waters of the east 
span of the SFOBB. Density estimates for other species were made from 
stranding data provided by the MMC (Sausalito, CA; Northern elephant 
seal).

(1) Pacific Harbor Seal

    Most data on harbor seal populations are collected while the seals 
are hauled out. This is because it is much easier to count individuals 
when they are out of the water. In-water density estimates rely on 
haul-out counts, the percentage of seals not on shore based on radio 
telemetry studies, and the size of the foraging range of the 
population. Harbor seal density in the water can vary greatly depending 
on weather conditions or the availability of prey. For example, during 
Pacific herring runs further north in the Bay (near Richardson Bay, 
outside of the Pier E3 hydroacoustic zone) in February 2014, very few 
harbor seals were observed foraging near Yerba Buena Island (YBI) or 
transiting through the SFOBB area for approximately two weeks. 
Sightings went from a high of 16 harbor seal individuals foraging or in 
transit in one day to 0-2 seals per day in transit or foraging through 
the SFOBB area (CALTRANS 2014). Calculated harbor seal density is a per 
day estimate of harbor seals in a 1 km\2\ area within the fall/winter 
or spring/summer seasons.
    Harbor seal density for the proposed project was calculated from 
all observations during SFOBB Project monitoring from 2000 to 2014. 
These observations included data from baseline, pre, during and post 
pile driving and onshore implosion activities. During this time, the 
population of harbor seals within the Bay has remained stable (Manugian 
2013), therefore, we do not anticipate significant differences in 
numbers or behaviors of seals hauling out, foraging or in their 
movements over that 15 year period. All harbor seal observations within 
a km 2 area were used in the estimate. Distances were 
recorded using a laser range finder (Bushnell Yardage Pro Elite 1500; 
1.0 yards accuracy). Care was taken to eliminate multiple 
observations of the same animal although this was difficult when more 
than three seals were foraging in the same area.
    Density of harbor seals was highest near YBI and Treasure Island, 
probably due to the haul-out site and nearby foraging areas in the 
Coast Guard and Clipper coves. Therefore, density estimates were 
calculated for a higher density area within 3,936 ft (1,200 m) west of 
Pier E3, which includes these two foraging coves. A lower density 
estimate was calculated from the area east of Pier E3 and beyond 3,936 
ft (1,200 m) to the north and south of Pier E3.
    These density estimates were then extrapolated to the threshold 
criteria areas delineated by the hydroacoustic models to calculate the 
number of harbor seals likely to be exposed.

(2) California Sea Lion

    Most data on California sea lion populations are collected while 
the seals are hauled out as it is much easier to count individuals when 
they are out of the water. In-water density estimates rely on haul-out 
counts, the percentage of sea lions not on shore based on radio 
telemetry studies, and the size of the foraging range of the 
population. Sea lion density, like harbor seal densities, in the water 
can vary greatly depending on weather conditions, the availability of 
prey, and the season. For example, sea lion density increases during 
the summer and fall after the end of the breeding season at the 
Southern California rookeries.
    For the proposed project, California sea lion density was 
calculated from all observations during SFOBB monitoring from 2000 to 
2014. These observations included data from baseline, pre, during and 
post pile driving and onshore implosion activities. During this time, 
the population of sea lions within the Bay has remained stable as have 
the numbers observed near the SFOBB (Manugian 2013). As a result, we do 
not anticipate significant differences in the number of sea lion or 
their movements over that 15 year period. All sea lion observations 
within a km\2\ area were used in the estimate. Distances were recorded 
using a laser range finder (Bushnell Yardage Pro Elite 1500; 1.0 yards accuracy). Care was taken to eliminate multiple 
observations of the same animal, although most sea lion observations 
involve a single animal. Calculated California sea lion density is a 
per day estimate of sea lions in a one km\2\ area within the fall/
winter or spring/summer seasons.

(3) Northern Elephant Seal

    Northern elephant seal density around Pier E3 was calculated from 
the stranding records of the MMC from 2004 to 2014. These data included 
both injured or sick seals and healthy seals. Approximately 100 
elephant seals were reported within the Bay during this time, most of 
these hauled out and were likely sick or starving. The actual number of 
individuals within the Bay may be higher as not all individuals would 
necessarily have hauled out. Some individuals may have simply left the 
Bay soon after entering. Data from the MMC show several elephant seals 
stranding on Treasure Island and one healthy elephant seal was observed 
resting on the beach in Clipper Cove in 2012. Elephant seal pups or 
juveniles also may strand after weaning in the spring and when they 
return to California in the fall (September through November).

(4) Harbor Porpoise

    Harbor porpoise density was calculated from all observations during 
SFOBB monitoring from 2000 to 2014. These observations included data 
from baseline, pre, during and post pile driving and onshore implosion 
activities. Over this period, the number of harbor porpoises that were 
observed entering and using the Bay increased. During the fifteen years 
of observational data around the SFOBB Project, only

[[Page 44070]]

four harbor porpoises were observed and all occurred from 2006 to 2014 
(including two in 2014). All harbor porpoise observations within a 
km\2\ area were used in the estimate. Distances were recorded using a 
laser range finder (Bushnell Yardage Pro Elite 1500;  1.0 
yards accuracy).
    A summary of marine mammal density information is provided in Table 
4.
[GRAPHIC] [TIFF OMITTED] TN24JY15.001

Impact Zones Modeling

    Since the proposed Pier E3 controlled implosion would be carried as 
a confined explosion, certain elements were taken into the modeling 
process beyond a simple open-water blast model. Confinement is a 
concept in blasting that predicts the amount of blast energy that is 
expected to be absorbed by the surrounding structural material, 
resulting in the fracturing necessary for demolition. The energy beyond 
that absorbed by the material is the energy that produces the pressure 
wave propagating away from the source. NMFS has determined that 
modeling with confinement was appropriate for the proposed Pier E3 
blast by evaluating blast results from case study data for underwater 
implosions similar to the proposed SFOBB Pier E3 implosion. In 
addition, the NMFS worked with CALTRANS and compared case study results 
to published blast models that incorporate a degree of confinement.
    Data from 39 comparable underwater concrete blasts were used by 
CALTRANS to evaluate potential equations for modeling blast-induced 
peak pressures and subsequent effects to marine mammals (Kiewit-Mason, 
pers. Comm 2015 in CALTRANS 2015). All 39 blasts occurred in 
approximately 55 ft (16.8 m) of water, similar to the maximum water 
depth around Pier E3. In addition, all blasts had burdens (i.e., 
distance from the charge to the outside side of the material being 
fractured) of approximately 1.5 to 2 ft (0.5 to 0.6 m). Burdens for 
Pier E3 also are estimated to be in this range. Data provided included 
the charge weight, observed peak pressure, distance of peak pressure 
observation, and the modeled peak pressure using Cole's confined 
equation, Cole's unconfined equation, and Oriard's conservative 
concrete equation (Cole 1948; Oriard 2002).
    Using these data, appropriate equations for modeling the associated 
hydroacoustic impacts are established for the Pier E3 controlled 
implosion. Cole's unconfined equation greatly overestimated peak 
pressures for all blasts while Cole's confined equation appeared to 
most accurately predict observed peak pressures. Oriard's conservative 
concrete equation overestimated peak pressures, but not as dramatically 
as under Cole's unconfined equation. NMFS and CALTRANS have opted to 
use more conservative methods to ensure an additional level of safety 
when predicting the monitoring zone and potential impact areas to 
marine mammals from the proposed controlled implosion project.
    The applicable metrics discussed are the peak pressure 
(Ppk) expressed in dB, the accumulated sound exposure level 
(SEL) also expressed in dB, and the positive acoustic impulse (I) in 
Pa-sec. The criteria for marine mammals are grouped into behavioral 
response, slight injury, mortality, and the specific acoustic 
thresholds depend on group and species. These are summarized in Table 
1. The metrics for these are criteria defined as:

[[Page 44071]]

[GRAPHIC] [TIFF OMITTED] TN24JY15.002

General Assumptions

    The blast event will consist of a total of 588 individual delays of 
varying charge weight; the largest is 35 pounds/delay and the smallest 
is 21 pounds/delay. The blasting sequence is rather complex. On the 
full height walls, 30 pound weights will be used for the portion below 
mud line, 35 pound weights will be used in the lower structure 
immediately above mud line, 29.6 pounds in the midstructure, and 21 
pounds in the upper structure. Full details on the delay weights and 
locations can be found in the Blast Plan (CALTRANS 2015). Blasts will 
start in several interior webs of the southern portion of the structure 
followed by the outer walls of the south side. The blasts in the inner 
walls will occur just prior to the adjacent outer walls. The interior 
first, exterior second blast sequence will continue across the 
structure moving from south to north. The time for the 588 detonations 
is 5.3 seconds with a minimum delay time of 9 milliseconds (ms) between 
detonations. As the blasting progresses, locations to east, north, and 
west of the pier will be shielded from the blasting on the interior of 
the structure from the still-standing exterior walls of the pier. 
However, towards the conclusion of the blast, each direction will 
experience blasts from the outer walls that are not shielded.
    To estimate Ppk and P\2\(t), several assumptions were made. For 
simplification, it was assumed that there is only one blast distance 
and it is to the closest point on the pier from the receiver point. In 
actuality for almost all explosions, distances from the blast will be 
greater as the pier is approximately 135 ft (41 m) across and 80 ft (24 
m) wide. Based on these dimensions, the actual blast point could be up 
to 135 ft (41 m) further from the receptor point used for the 
calculation. As a result, the calculated peak level is the maximum 
expected for one 35 pound blast while the other levels would be lower 
depending on the distance from the actual blast location to the 
calculation point and weight of the charge. In other words, the 
pressure received at the calculation point would not be 588 signals of 
the same amplitude, but would be from one at the estimated level for a 
35 pound charge and 587 of varying lower amplitudes. Similarly, in the 
vertical direction, the location varies over a height of about 50 ft 
(15 m) and those blasts that are not at the same depth as the receiver 
would also be lower. This effect of variation in assumed blast to 
receiver distance will be most pronounced close to the pier, while at 
distances of about 1,000 ft (305 m) or greater, the effect would be 
less than 1 dB.
    In the calculations, it was also assumed that there would be no 
self-shielding of the pier as the explosions progress. From the above 
discussion of the blast sequence, some shielding of the blasts along 
the interior of the pier will occur. However, the blasts that occur in 
outer wall (towards the end of the implosion) will not be shielded for 
all blasts. A blast in the outer wall that has a direct line of sight 
to the receptor calculation point will not be shielded and will 
generate the highest peak

[[Page 44072]]

pressure relative to be compared to the Lpk criterion. The 
cumulative SEL and the root-mean-squared (RMS) levels; however, will be 
reduced to some degree by the outer walls until they are demolished as 
these metrics are defined by the pressure received throughout the 
entire 5.3 second event. However, due to the complexity of the blast 
sequence, this shielding effect was not considered in the calculated 
SEL and RMS levels.
    Based on the Blast Plan (CALTRANS 2015), the delays are to be 
placed in 2\3/4\ to 3 inch (7 to 7.6 cm) diameter holes drilled into 
the concrete pier structure. The outer walls of the pier are nominally 
3 ft-11\1/2\ inch (1.5 m) thick and inner walls are nominally 3 ft (0.9 
m) thick. Individual blasts should be not exposed to open water and 
some confinement of the blasts is expected. For confined blasts, the 
predicted pressures can be reduced by 65 to 95% (Nedwell and 
Thandavamoorthy 1992; Rickman 2000; Oriard 2002; Rivey 2011), 
corresponding to multiplication factors from 0.35 to 0.05, 
respectively. Based on a review of the available literature and recent 
data from similar explosive projects, CALTRANS and NMFS decided to use 
a conservative confinement factor of K=7500 which equates to a 65% 
reduction in pressure and by a multiplication factor of 0.3472 (Eq. 4).
    Another assumption was to consider only the direct wave from an 
individual blast. In shallow water, the signal at the receiver point 
could consist of the direct wave, surface-relief wave generated by the 
water/air interface, a reflected wave from the bottom, and a wave 
transmitted through the bottom material (USACE 1991). For estimating 
Ppk, only the direct wave is considered as it will have the highest 
magnitude and will arrive at the receiver location before any other 
wave component. However, P(t) after the arrival of the direct wave peak 
pressure will be effected. The surface-relief wave is negative so that 
when it arrives at the receiver location, it will reduce the positive 
pressure of the direct wave and can make the total pressure negative at 
times after the arrival of the initial positive peak pressure. Since 
the SEL is a pressure squared quantity, any negative pressure can also 
contribute to the SEL. However, the amplitude and arrival time of the 
surface-relief wave depends on the geometry of the propagation case, 
that is, depth of water, depth of blast, and distance and depth of the 
receiver point. The effect of this assumption is discussed further in 
the section on SEL.

Estimation of Peak Pressure

    Peak pressures were estimated by following the modified version of 
the Cole Equation for prediction of blasts in open, deep water (Cole 
1948). The peak pressure is determined by:
[GRAPHIC] [TIFF OMITTED] TN24JY15.003

where Ppk is peak pressure in pounds per square inch (psi), and 
[lambda] is the scaled range given by R/W\1/3\ in which R is the 
distance in feet and W is the weight of the explosive charge in pounds. 
A modified version of the Cole Equation has been documented in U.S. 
Army Corps of Engineer (USACE) Technical Letter No. 1110-8-11(FR) and 
is applicable to shallow water cases such as that of the Pier E3 
demolition (USACE 1991). The constant K factor multiplier in the USACE 
calculation is 21,600 for an open-water blast instead of the 22,550 
from the original Cole Expression. This factor is slightly less (~4%) 
than the original Cole. The decay factor (-1.13) used in the USACE 
modified equation remains the same as the original Cole Equation. To 
account for the confining effect of the concrete pier structure, a 
conservative K factor of 7,500 was used corresponding to multiplying 
USACE Ppk by a factor of 0.3472. With a minimum delay between of blast 
of 9 ms, the individual delays will be spaced sufficiently far in time 
to avoid addition of the peak pressures. In this case, the peak 
pressure is defined by that calculated for the largest charge weight of 
35 pounds/delay. A BAS is specified in the Blast Plan. Based on the 
literature and recent results from similar projects, reductions in the 
pressure peak of 85% to 90% or more are expected. For determining Ppk 
in this analysis, a conservative reduction of 80% has been used. Based 
on values of confinement, BAS performance, and the ``General 
Assumptions'' above, the calculated peak pressures are expected to be 
conservative.

Estimation of SEL Values

    Estimating the weighted SEL values for the different groups/species 
is a multiple step process. The first step is to estimate SEL values as 
a function of distance from the blast pressure versus time histories 
for each of the six charge weights as a function of distance. The open-
water equation used for this calculation was that modified by the USACE 
(1991) based on methods pioneered by Cole (1948). Pressure as a 
function of time is given by:
[GRAPHIC] [TIFF OMITTED] TN24JY15.004

    These calculations were then extended to distances out to 160,000 
ft (48.8 km).
    As discussed previously, there are other wave components that could 
be considered in the SEL estimation, including the surface relief wave, 
reflection from the bottom, and transmission through and re-radiation 
from the bottom. Little or no contribution is expected from the bottom 
based on its sedimentary nature and previous experiences from measuring 
noise from underwater pile driving in the area around Pier E3. The 
negative surface relief wave could be a factor in the SEL estimation. 
This wave could either increase or decrease the

[[Page 44073]]

SEL depending on its arrival time relative to the direct wave. For 
small differences in arrival time, the surface relief will decrease the 
total SEL as a portion of the positive direct wave is negated by the 
addition of the negative surface relief wave. For closer distances and 
when the receptor and blast locations are near the bottom, the total 
SEL can become greater than the direct wave SEL, but only by less than 
3 dB. However, whenever the source or receiver is near the surface, the 
direct wave SEL will be greater than the total SEL and can approach 
being 10 dB greater for distances beyond 1,000 ft (305 m). As a result, 
the surface relief wave is ignored in this analysis knowing that the 
surface relief wave would only tend to produce lower SEL values than 
the direct wave.
    For each of the marine mammal groupings included in Table 2, 
specific filter shapes apply to each functional hearing group. To apply 
this weighting, the Fast Fourier Transform (FFT) was calculated for the 
time histories at each analysis distance. Each FFT was then filtered 
using the frequency weighted specified for each group. Filter factors 
were then determined for each distance by subtracting the filtered 
result from the unfiltered FFT data and determining the overall noise 
reduction in decibels. These filter factors were applied to the 
accumulated SEL determined for the entire blast event for each distance 
from the Pier.
    The BAS of the Blast Plan will have an effect on the wave once a 
blast passes through it. In a research report by USACE in 1964, the 
performance of a BAS was examined in detail (USACE 1964). It has also 
been found that for an energy metric such as SEL, the reduction 
produced by the BAS was equal to or greater than the reduction of the 
peak pressure (USACE 1991; Rude 2002; Rude and Lee 2007; Rivey 2011). 
To estimate the reduction for SEL values due to the BAS proposed in the 
Blast Plan (CALTRANS 2015), SEL was reduced by 80%. Effectively, this 
was done by reducing the SEL by 20 Log (0.20), or 14 dB. Delays below 
the mudline, which will be located below the BAS, were also reduced by 
80% based on an assumption that the outside pier walls here (which will 
not be removed) and Bay mud sediments will provide a similar level of 
attenuation. These SEL values and those without the BAS were then 
compared to the appropriate criteria for each marine mammal group. 
Because the calculation of SEL is based on the peak pressure, these 
estimates for the direct wave component are expected to be conservative 
for the same reasons as described for the peak pressures.

Estimation of Positive Impulse

    To estimate positive impulse values, the expression originally 
developed by Cole for open water was used (Cole 1948). This expression 
includes only contributions from the direct wave neglecting any 
contribution from the surface relief, bottom reflected, and bottom 
transmitted consistent with the assumptions used to estimate SEL. In 
this case, impulse is given by:
[GRAPHIC] [TIFF OMITTED] TN24JY15.005

with the variables defined in Equation 4. The impulse can also 
equivalently be calculated from wave forms. Equation 5 produces impulse 
values in psi-msec which were converted to Pa-sec by multiplying by 6.9 
for comparison to the marine mammal criteria.
    Unlike Ppk and SEL, no reduction by the BAS is assumed 
for the impulse calculation. The area under the P(t) curve under goes 
little change after passing the BAS. The peak pressure is reduced as 
noted previously, however, since the P(t) expands in duration, the area 
change is minimal. This behavior is well documented in the literature 
(Cole 1948; USACE 1964; USACE 1991; Rickman 2000). As discussed above, 
this is not the case for SEL which is determined by the area under the 
P\2\(t) curve.

Estimated Takes of Marine Mammals

    The estimated distances (Table 5) to the marine mammal criteria for 
peak pressure, SEL, and impulse are based on established relationships 
between charge weight and distance from the literature. The estimated 
distances were determined assuming unconfined open water blasts from 
the original Cole equations or the Cole equations modified by USACE. 
The assumption of open water neglects several effects that could 
produce lower levels than estimated. These include no shielding by the 
pier structure prior a specific blast, confining of the individual 
delays in the holes drilled into the pier structure, and longer 
distances to individual blasts than assumed by closest distance between 
the pier and the receptor point. For SEL, the assumption of open water 
blasts neglects the surface relief wave which at longer distances from 
the pier, would tend to reduce the SEL due to interference with the 
direct wave. Although the estimated levels and distances may be 
conservative, there is sufficient uncertainty in the blast event and 
its propagation such that further, less conservative adjustments would 
not be appropriate.
    Estimated exposure numbers are subsequently calculated based on 
modeled ensonified areas and marine mammal density information. 
However, since many marine mammals are expected to occur in groups, the 
estimated exposure numbers are adjusted upward by a factor of 2 to 
provide estimated take numbers. In addition, although modeling shows 
that no California sea lion would be exposure to noise levels that 
would result a take, its presence in the vicinity of SFOBB has been 
documented. Therefore, a take of 2 of California sea lion is assessed. 
A summary of estimated takes and exposures of marine mammals that could 
result from CALTRANS' Pier E3 controlled implosion is provided in Table 
5.

[[Page 44074]]



     Table 5--Summary of the Estimated Takes and Exposures (in Parenthesis) of Marine Mammals to the Pire E3
                                                    Implosion
----------------------------------------------------------------------------------------------------------------
                                          Level B take
              Species              --------------------------   Level A     Mortality    Population     % take
                                     Behavioral      TTS          take                                population
----------------------------------------------------------------------------------------------------------------
Pacific harbor seal...............       12 (6)        6 (3)        0 (0)        0 (0)       30.196         0.06
California sea lion...............        2 (0)        0 (0)        0 (0)        0 (0)      296,750         0.00
Northern elephant seal............        2 (1)        0 (0)        0 (0)        0 (0)      124,000         0.00
Harbor porpoise...................        2 (1)        0 (0)        0 (0)        0 (0)        9,886         0.02
----------------------------------------------------------------------------------------------------------------

Analysis and Preliminary Determinations

Negligible Impact

    Negligible impact is ``an impact resulting from the specified 
activity that cannot be reasonably expected to, and is not reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival'' (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of 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 must consider 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 harassment takes, 
the number of estimated mortalities, and effects on habitat.
    To avoid repetition, this introductory discussion of our analyses 
applies to all the species listed in Table 5, given that the 
anticipated effects of CALTRANS' Pier E3 controlled implosion on marine 
mammals are expected to be relatively similar in nature. There is no 
information about the nature or severity of the impacts, or the size, 
status, or structure of any species or stock that would lead to a 
different analysis for this activity, else species-specific factors 
would be identified and analyzed.
    No injuries or mortalities are anticipated to occur as a result of 
CALTRANS' controlled implosion to demolish Pier E3, and none are 
proposed to be authorized. The relatively low marine mammal density and 
small Level A exclusion zones make injury takes of marine mammals 
unlikely, based on take calculation described above. In addition, the 
Level A exclusion zones would be thoroughly monitored before the 
proposed implosion, and detonation activity would be postponed if an 
marine mammal is sighted within the exclusion.
    The takes that are anticipated and authorized are expected to be 
limited to short-term Level B harassment (behavioral and TTS). Marine 
mammals (Pacific harbor seal, northern elephant seal, California sea 
lion, and harbor porpoise) present in the vicinity of the action area 
and taken by Level B harassment would most likely show overt brief 
disturbance (startle reaction) and avoidance of the area form the 
implosion noise. A few Pacific harbor seals could experience TTS if 
they occur within the Level B TTS ZOI. However, as discussed early in 
this document, TTS is a temporary loss of hearing sensitivity when 
exposed to loud sound, and the hearing threshold is expected to recover 
completely within minutes to hours. Therefore, it is not considered an 
injury. In addition, even if an animal receives a TTS, the TTS would 
just be a one-time event from a brief impulse noise (about 5 seconds), 
making it unlikely that the TTS would involve into PTS. Finally, there 
is no critical habitat and other biologically important areas in the 
vicinity of CALTRANS' proposed Pier E3 controlled implosion area (John 
Calambokidis et al. 2015).
    The project also is not expected to have significant adverse 
effects on affected marine mammals' habitat, as analyzed in detail in 
the ``Anticipated Effects on Marine Mammal Habitat'' section. The 
project activities would not modify existing marine mammal habitat. The 
activities may kill some fish and cause other fish to leave the area 
temporarily, thus impacting marine mammals' foraging opportunities in a 
limited portion of the foraging range; but, because of the short 
duration of the activities and the relatively small area of the habitat 
that may be affected, the impacts to marine mammal habitat are not 
expected to cause significant or long-term negative consequences.
    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 CALTRANS's Pier E3 demolition via controlled implosion 
will have a negligible impact on the affected marine mammal species or 
stocks.

Small Number

    The requested takes represent less than 0.06% of all populations or 
stocks potentially impacted (see Table 5 in this document). These take 
estimates represent the percentage of each species or stock that could 
be taken by Level B behavioral harassment and TTS (Level B harassment). 
The numbers of marine mammals estimated to be taken are small 
proportions of the total populations of the affected species or stocks. 
In addition, the mitigation and monitoring measures (described 
previously in this document) prescribed in the proposed IHA are 
expected to reduce even further any potential disturbance to marine 
mammals.
    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 mitigation and monitoring 
measures, NMFS preliminarily finds that small numbers of marine mammals 
will be taken relative to the populations of the affected species or 
stocks.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    There are no subsistence uses of marine mammals in the proposed 
project area; and, thus, no subsistence uses impacted by this action. 
Therefore, NMFS has determined that the total taking of affected 
species or stocks would not have an unmitigable adverse impact on the 
availability of such species or stocks for taking for subsistence 
purposes.

Endangered Species Act (ESA)

    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.

[[Page 44075]]

National Environmental Policy Act (NEPA)

    NMFS prepared an Environmental Assessment (EA) and a Supplemental 
Environmental Assessment (SEA) for the take of marine mammals 
incidental to construction of the East Span of the SF-OBB and made 
Findings of No Significant Impact (FONSIs) on November 4, 2003 and 
August 5, 2009. Due to the modification of part of the demolition of 
the original SFOBB using controlled implosion and the associated 
mitigation and monitoring measures, NMFS prepared a draft SEA and 
analyzed the potential impacts to marine mammals that would result from 
the modification. NMFS has released the draft SEA for public comment 
along with this proposed IHA.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to CALTRANS for conducting Pier E3 demolition via 
controlled implosion, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated. The proposed 
IHA language is provided next.
    1. This Authorization is valid from October 1 through December 30, 
2015.
    2. This Authorization is valid only for activities associated the 
original San Francisco-Oakland Bay Bridge Pier E3 demolition via 
controlled implosion and a pre-demolition test implosion in San 
Francisco Bay.
    3. (a) The species authorized for incidental harassment takings, 
Level B harassment only, are: Pacific harbor seal (Phoca vitulina 
richardsi), California sea lion (Zalophus californianus), northern 
elephant seals (Mirounga angustirostris), and harbor porpoise (Phocoena 
phocoena).
    (b) The authorization for taking by harassment is limited to the 
following acoustic sources and from the following activities:
     Pre-demolition test implosion;
     Pier E3 demolition via controlled implosion.
    (c) The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported within 24 hours of the taking to 
the West Coast Administrator (206-526-6150), National Marine Fisheries 
Service (NMFS) and the Chief of the Permits and Conservation Division, 
Office of Protected Resources, NMFS, at (301) 427-8401, or her designee 
(301-427-8418).
    4. The holder of this Authorization must notify the Chief of the 
Permits and Conservation Division, Office of Protected Resources, at 
least 48 hours prior to the start of activities identified in 3(b) 
(unless constrained by the date of issuance of this Authorization in 
which case notification shall be made as soon as possible).
5. Prohibitions
    (a) The taking, by incidental harassment only, is limited to the 
species listed under condition 3(a) above and by the numbers listed in 
Table 5. The taking by Level A harassment, injury or death of these 
species or the taking by harassment, injury or death of any other 
species of marine mammal is prohibited and may result in the 
modification, suspension, or revocation of this Authorization.
    (b) The taking of any marine mammal is prohibited whenever the 
required protected species observers (PSOs), required by condition 
7(a), are not present in conformance with condition 7(a) of this 
Authorization.
6. Mitigation
(a) Time Restriction
    Implosion of Pier E3 shall only be conducted during daylight hours 
and with enough time for pre and post implosion monitoring, and with 
good visibility when the largest exclusion zone can be visually 
monitored.
(b) Installation of Blast Attenuation System (BAS)
    Prior to the Pier E3 demolition, CALTRANS should install a Blast 
Attenuation System (BAS) to reduce the shockwave from the implosion.
(c) Establishment of Exclusion Zones and Zones of Influence
    Before CALTRANS begins Pier E3 demolition via controlled implosion 
and the pre-demolition test implosion, exclusion zones and zones of 
influence (ZOIs) that are appropriate to specific marine mammal 
functional hearing group shall be established. The modeled isopleth of 
these zones are provided in Table 3.
(d) Exclusion Zone Monitoring for Mitigation Measures
    (i) The exclusion zone shall be monitored by protected species 
observers (PSOs) for at least 30 minutes before the implosion.
    (ii) If any marine mammals are observed inside the exclusion, the 
implosion will be delayed until the animal leaves the area or at least 
30 minutes have passed since the last observation of the marine mammal.
(e) Communication
    The Lead PSO shall be in constant contact with the Resident 
Engineer on site and the blasting crew to ensure that no marine mammal 
is within the exclusion zone before the controlled implosion.
    7. Monitoring:
    (a) Protected Species Observers:
    (i) CALTRANS shall employ NMFS-approved PSOs to conduct marine 
mammal monitoring for its Pier E3 demolition via controlled implosion.
    (ii) A minimum of 8-10 PSOs shall be required during the Pier E3 
controlled implosion so that the exclusion zone, Level B Harassment TTS 
and Behavioral ZOIs, and surrounding area can be monitored.
    (b) Monitoring Protocol:
    (i) PSOs shall be positioned near the edge of each of the thredhold 
criteria zones and shall utilize boats, barges, bridge piers and 
roadway, and sites on Yerba Buena Island and Treasure Island, as 
described in Figure 3 of the CALTRANS Marine Mammal Monitoring Plan.
    (ii) The Lead PSO shall be located with the Department Engineer and 
the Blasting Supervisor (or person that will be in charge of detonating 
the charges) during the implosion.
    (iii) The Lead PSO will be in contact with other PSOs and the 
acoustic monitors. As the time for the implosion approaches, any marine 
mammal sightings would be discussed between the Lead PSO, the Resident 
Engineer, and the Blasting Supervisor.
    (iv) If any marine mammals enter the exclusion zone within 30 
minutes of blasting, the Lead PSO shall notify the Resident Engineer 
and Blasting Supervisor that the implosion may need to be delayed. The 
Lead PSO shall keep them informed of the disposition of the animal.
    (v) Once the implosion has occurred, the PSOs will continue to 
monitor the area for at least 60 minutes.
    (c) Post-implosion Survey:
    (i) Boat or shore surveys shall be conducted for the three days 
following the event to determine if there are any injured or stranded 
marine mammals in the area.
    (ii) If an injured or dead animal is discovered during these 
surveys or by other means, the NMFS-designated stranding team shall be 
contacted to pick up the animal. Veterinarians will treat the animal or 
conduct a necropsy to attempt to determine if it stranded was a result 
of the Pier E3 implosion.
    (d) Monitoring Data Collection:
    (i) Each PSO shall record their observation position, start and end

[[Page 44076]]

times of observations, and weather conditions (sunny/cloudy, wind 
speed, fog, visibility).
    (ii) For each marine mammal sighting, the following shall be 
recorded, if possible:

 Species
 Number of animals (with or without pup/calf)
 Age class (pup/calf, juvenile, adult)
 Identifying marks or color (scars, red pelage, damaged dorsal 
fin, etc.)
 Position relative to Pier E3 (distance and direction)
 Movement (direction and relative speed)
 Behavior (logging [resting at the surface], swimming, 
spyhopping [raising above the water
 surface to view the area], foraging, etc.)
 Duration of sighting or times of multiple sightings of the 
same individual

    (e) Real Time Acoustic Monitoring for Harbor Porpoises:
    (i) Real time acoustic monitoring (PAM) system shall be used to 
detect the presence or absence of harbor porpoises as a supplement to 
visual monitoring.
    (ii) Real time PAM shall involve two bio-acousticians monitoring 
the site near the north end of Treasure Island.
    (iii) Real time PAM shall use a hydrophone or towed array suspended 
from a boat and/or several sonobuoys, or a hydrophone moored offshore 
with a cable leading to a shore based acoustic station outside of the 
monitoring area of Pier E3.
    (iv) All equipment used for real time PAM shall be calibrated and 
tested prior to the implosion to ensure functionality.
    (v) The bio-acousticians shall be in communication with the Lead 
PSO and shall alert the crew to the presence of any cetacean 
approaching the monitoring area. The bio-acousticians shall also 
provide further confirmation that there are no cetaceans around Pier E3 
in addition to the visual observations documenting no observations.
    (f) Hydroacoustic Monitoring for Underwater Implosion:
    (i) Hydroacoustic monitoring of sound field from the controlled 
implosion shall be conducted in near field and far field regions around 
Pier E3
    (A) Near field measurements shall be taken within 500 ft of the 
Pier
    (B) Far field measurements shall be taken at 500 feet and all 
greater distances from the Pier.
    (ii) Near field and far field measurements protocols
    (A) Measurements inside the BAS shall be made with near and far 
field systems using PCB 138A01 transducers. At the 100-ft distance, the 
near field system will use another PCB 138A01 transducer.
    (B) Far field measurements shall be conducted using both a PCB 
138A01 transducer and a Reson TC4013 hydrophone.
    (iii) Ambient and background noise measurements
    (A) Prior to activating the BAS, ambient noise levels shall be 
measured.
    (B) While the BAS is operating and before the test implosion, 
background noise measurements shall also be made.
    (C) After the test implosion, the results shall be evaluated to 
determine if any final adjustments are needed in the measurement 
systems prior to the Pier E3 controlled implosion.
    (D) Pressure signals shall be analyzed for peak pressure and SEL 
values prior to the scheduled time of the Pier E3 controlled implosion.
    8. Reporting:
    (a) CALTRANS shall submit a draft monitoring report within 90 days 
after completion of the construction work or the expiration of the IHA 
(if issued), whichever comes earlier. This report would detail the 
monitoring protocol, summarize the data recorded during monitoring, and 
estimate the number of marine mammals that may have been harassed.
    (b) NMFS would have an opportunity to provide comments within 30 
days after receiving the draft report, and if NMFS has comments, 
CALTRANS shall address the comments and submit a final report to NMFS 
within 30 days.
    (c) If NMFS does not provide comments within 30 days after 
receiving the report, the draft report is considered to be final.
    9. Marine Mammal Stranding Plan:
    A marine mammal stranding plan shall be prepared in cooperation 
with the local NMFS-designated marine mammal stranding, rescue, and 
rehabilitation center. Elements of that plan would include the 
following:
    (a) The stranding crew shall prepare treatment areas at the NMFS-
designated facility for cetaceans or pinnipeds that may be injured from 
the implosion. Preparation shall include equipment to treat lung 
injuries, auditory testing equipment, dry and wet caged areas to hold 
animals, and operating rooms if surgical procedures are necessary. 
Equipment to conduct auditory brainstem response hearing testing would 
be available to determine if any inner ear threshold shifts (TTS or 
PTS) have occurred.
    (b) A stranding crew and a veterinarian shall be on call near the 
Pier E3 site at the time of the implosion to quickly recover any 
injured marine mammals, provide emergency veterinary care, stabilize 
the animal's condition, and transport individuals to the NMFS-
designated facility. If an injured or dead animal is found, NMFS (both 
the regional office and headquarters) shall be notified immediately 
even if the animal appears to be sick or injured from other than 
blasting.
    (c) Post-implosion surveys shall be conducted immediately after the 
event and over the following three days to determine if there are any 
injured or dead marine mammals in the area.
    (d) Any veterinarian procedures, euthanasia, rehabilitation 
decisions and time of release or disposition of the animal shall be at 
the discretion of the NMFS-designated facility staff and the 
veterinarians treating the animals. Any necropsies to determine if the 
injuries or death of an animal was the result of the blast or other 
anthropogenic or natural causes will be conducted at the NMFS-
designated facility by the stranding crew and veterinarians. The 
results shall be communicated to both CALTRANS and to NMFS as soon as 
possible with a written report within a month.
    10. 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, or if there is an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses.
    11. A copy of this Authorization must be in the possession of each 
contractor who performs the pre-demolition test implosion and Pier E3 
controlled implosion work.

    Dated: July 21, 2015.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2015-18178 Filed 7-23-15; 8:45 am]
 BILLING CODE 3510-22-P