Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Wharf Construction Project, 32827-32858 [2014-12906]
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Vol. 79
Friday,
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June 6, 2014
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine
Mammals Incidental to a Wharf Construction Project; Notice
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Federal Register / Vol. 79, No. 109 / Friday, June 6, 2014 / Notices
Ben
Laws, Office of Protected Resources,
NMFS, (301) 427–8401.
SUPPLEMENTARY INFORMATION:
FOR FURTHER INFORMATION CONTACT:
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
RIN 0648–XD282
Takes of Marine Mammals Incidental to
Specified Activities; Taking Marine
Mammals Incidental to a Wharf
Construction Project
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
AGENCY:
Notice; proposed incidental
harassment authorization; request for
comments.
ACTION:
NMFS has received a request
from the U.S. Navy (Navy) for
authorization to take marine mammals
incidental to construction activities as
part of a wharf construction project.
Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is
requesting comments on its proposal to
issue an incidental harassment
authorization (IHA) to the Navy to
incidentally take marine mammals, by
Level B Harassment only, during the
specified activity.
SUMMARY:
Comments and information must
be received no later than July 7, 2014.
DATES:
Comments on the
application should be addressed to Jolie
Harrison, Supervisor, Incidental Take
Program, Permits and Conservation
Division, Office of Protected Resources,
National Marine Fisheries Service.
Physical comments should be sent to
1315 East-West Highway, Silver Spring,
MD 20910 and electronic comments
should be sent to ITP.Laws@noaa.gov.
Instructions: NMFS is not responsible
for comments sent by any other method,
to any other address or individual, or
received after the end of the comment
period. Comments received
electronically, including all
attachments, must not exceed a 25megabyte file size. Attachments to
electronic comments will be accepted in
Microsoft Word or Excel or Adobe PDF
file formats only. All comments
received are a part of the public record
and will generally be posted to the
Internet at www.nmfs.noaa.gov/pr/
permits/incidental.htm without change.
All personal identifying information
(e.g., name, address) voluntarily
submitted by the commenter may be
publicly accessible. Do not submit
confidential business information or
otherwise sensitive or protected
information.
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ADDRESSES:
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Availability
An electronic copy of the Navy’s
application and supporting documents,
as well as a list of the references cited
in this document, may be obtained by
visiting the Internet at:
www.nmfs.noaa.gov/pr/permits/
incidental.htm. In case of problems
accessing these documents, please call
the contact listed above (see FOR
FURTHER INFORMATION CONTACT).
National Environmental Policy Act
(NEPA)
The Navy prepared an Environmental
Impact Statement (EIS) for this project.
We acted as a cooperating agency on
development of that analysis and
subsequently adopted the EIS and
issued our own Record of Decision
(ROD; 2012), prior to issuing the first
IHA for this project, in accordance with
NEPA and the regulations published by
the Council on Environmental Quality.
We reaffirmed the existing 2012 ROD
before issuing an IHA in 2013 for the
second year of project construction.
Information in the Navy’s application,
the Navy’s EIS (2012), and this notice
collectively provide the environmental
information related to proposed
issuance of this IHA for public review
and comment. All documents are
available at the aforementioned Web
site, with the exception of the Navy’s
EIS, which is publicly available at
www.nbkeis.com (accessed May 2,
2014). We will review all comments
submitted in response to this notice as
we complete the NEPA process,
including a decision of whether to
reaffirm the existing ROD, prior to a
final decision on the incidental take
authorization request.
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 by U.S. citizens who
engage in a specified activity (other than
commercial fishing) within a specified
area, the incidental, but not intentional,
taking of small numbers of marine
mammals, providing that certain
findings are made and the necessary
prescriptions are established.
The incidental taking of small
numbers of marine mammals may be
allowed only if NMFS (through
authority delegated by the Secretary)
finds that the total taking by the
specified activity during the specified
time period will (i) have a negligible
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impact on the species or stock(s) and (ii)
not have an unmitigable adverse impact
on the availability of the species or
stock(s) for subsistence uses (where
relevant). Further, the permissible
methods of taking and requirements
pertaining to the mitigation, monitoring
and reporting of such taking must be set
forth, either in specific regulations or in
an authorization.
The allowance of such incidental
taking under section 101(a)(5)(A), by
harassment, serious injury, death, or a
combination thereof, requires that
regulations be established.
Subsequently, a Letter of Authorization
may be issued pursuant to the
prescriptions established in such
regulations, providing that the level of
taking will be consistent with the
findings made for the total taking
allowable under the specific regulations.
Under section 101(a)(5)(D), NMFS may
authorize such incidental taking by
harassment only, for periods of not more
than one year, pursuant to requirements
and conditions contained within an
IHA. The establishment of prescriptions
through either specific regulations or an
authorization requires notice and
opportunity for public comment.
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.
Except with respect to certain activities
not pertinent here, section 3(18) of the
MMPA defines ‘‘harassment’’ as any act
of pursuit, torment, or annoyance which
has the potential to injure a marine
mammal or marine mammal stock in the
wild; or 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.
The former is termed Level A
harassment and the latter is termed
Level B harassment.
Summary of Request
On January 10, 2014, we received a
request from the Navy for authorization
to take marine mammals incidental to
pile driving associated with the
construction of an explosives handling
wharf (EHW–2) in the Hood Canal at
Naval Base Kitsap in Bangor, WA
(NBKB). The Navy submitted a revised
version of the request on April 11, 2014,
which we deemed adequate and
complete. The Navy proposes to
continue this multi-year project,
involving impact and vibratory pile
driving conducted within the approved
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in-water work window. This IHA would
cover only the third year (in-water work
window) of the project, from July 16,
2014, through February 15, 2015.
The use of both vibratory and impact
pile driving is expected to produce
underwater sound at levels that have the
potential to result in behavioral
harassment of marine mammals. Species
with the expected potential to be
present during all or a portion of the inwater work window include the Steller
sea lion (Eumetopias jubatus
monteriensis), California sea lion
(Zalophus californianus), harbor seal
(Phoca vitulina richardii), killer whale
(transient only; Orcinus orca), and
harbor porpoise (Phocoena phocoena
vomerina). These species may occur
year-round in the Hood Canal, with the
exception of the Steller sea lion, which
is present only from fall to late spring
(approximately late September to early
May), and the California sea lion, which
is only present from late summer to late
spring (approximately late August to
early June).
This would be the third such IHA, if
issued. The Navy received IHAs,
effective from July 16–February 15, in
2012–13 (77 FR 42279) and 2013–14 (78
FR 43148). Additional IHAs were issued
to the Navy in recent years for marine
construction projects on the NBKB
waterfront. These projects include the
Test Pile Project (TPP), conducted in
2011–12 in the proposed footprint of the
EHW–2 to collect geotechnical data and
test methodology in advance of EHW–2
(76 FR 38361); a two-year maintenance
project on the existing explosives
handling wharf (EHW–1) conducted in
2011–12 and 2012–13 (76 FR 30130 and
77 FR 43049); and a minor project to
install a new mooring for an existing
research barge, conducted in 2013–14
(78 FR 43165). In-water work associated
with all projects was conducted only
during the approved in-water work
window (July 16–February 15).
Monitoring reports for all of these
projects are available on the Internet at
www.nmfs.noaa.gov/pr/permits/
incidental.htm and provide
environmental information related to
proposed issuance of this IHA for public
review and comment.
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Description of the Specified Activity
Overview
NBKB provides berthing and support
services to Navy submarines and other
fleet assets. The Navy proposes to
continue construction of the EHW–2
facility at NBKB in order to support
future program requirements for
submarines berthed at NBKB. The Navy
has determined that construction of
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EHW–2 is necessary because the
existing EHW alone will not be able to
support future program requirements.
All piles would be driven with a
vibratory hammer for their initial
embedment depths, while select piles
may be finished with an impact hammer
for proofing, as necessary. A maximum
of three vibratory drivers and one
impact driver may be used
simultaneously. Proofing involves
striking a driven pile with an impact
hammer to verify that it provides the
required load-bearing capacity, as
indicated by the number of hammer
blows per foot of pile advancement.
Sound attenuation measures (i.e.,
bubble curtain) would be used during
all impact hammer operations.
Dates and Duration
The allowable season for in-water
work, including pile driving, at NBKB is
July 16 through February 15, a window
established by the Washington
Department of Fish and Wildlife in
coordination with NMFS and the U.S.
Fish and Wildlife Service (USFWS) to
protect juvenile salmon. Under the
proposed action—which includes only
the portion of the project that would be
completed under this proposed IHA—a
maximum of 195 pile driving days
would occur. Pile driving may occur on
any day during the in-water work
window.
Impact pile driving during the first
half of the in-water work window (July
16 to September 15) may only occur
between two hours after sunrise and two
hours before sunset to protect breeding
marbled murrelets (an Endangered
Species Act [ESA]-listed bird under the
jurisdiction of USFWS). Vibratory
driving during the first half of the
window, and all in-water work
conducted between September 16 and
February 15, may occur during daylight
hours (sunrise to sunset). Other
construction (not in-water) may occur
between 7:00 a.m. and 10:00 p.m., yearround. Therefore, in-water work is
restricted to daylight hours (at
minimum) and there is at least a ninehour break during the 24-hour cycle
from all construction activity.
Specific Geographic Region
NBKB is located on the Hood Canal
approximately 32 km west of Seattle,
Washington (see Figures 2–1 through 2–
4 in the Navy’s application). The Hood
Canal is a long, narrow fjord-like basin
of the western Puget Sound. Throughout
its 108-km length, the width of the canal
varies from 1.6–3.2 km and exhibits
strong depth/elevation gradients and
irregular seafloor topography in many
areas. Although no official boundaries
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exist along the waterway, the
northeastern section extending from the
mouth of the canal at Admiralty Inlet to
the southern tip of Toandos Peninsula is
referred to as northern Hood Canal.
NBKB is located within this region.
Please see Section 2 of the Navy’s
application for detailed information
about the specific geographic region,
including physical and oceanographic
characteristics.
Detailed Description of Activities
Development of necessary facilities
for handling of explosive materials is
part of the Navy’s sea-based strategic
deterrence mission. The EHW–2
consists of two components: (1) The
wharf proper (or Operations Area),
including the warping wharf; and (2)
two access trestles. Please see Figures 1–
1 and 1–2 of the Navy’s application for
conceptual and schematic
representations of the EHW–2.
The wharf proper will lie
approximately 183 m offshore at water
depths of 18–30 m, and will consist of
the main wharf, a warping wharf, and
lightning protection towers, all pilesupported. It will include a slip
(docking area) for submarines,
surrounded on three sides by
operational wharf area. The access
trestles will connect the wharf to the
shore. There will be an entrance trestle
and an exit trestle; these will be
combined over shallow water to reduce
overwater area. The trestles will be pilesupported on 24-in steel pipe piles
driven approximately 9 m into the
seafloor. Spacing between bents (rows of
piles) will be 8 m. Concrete pile caps
will be cast in place and will support
pre-cast concrete deck sections.
For the entire project, a total of up to
1,250 permanent piles ranging in size
between 24–48 inches in diameter will
be driven in-water to construct the
wharf. Construction also requires
temporary installation of up to 150
falsework piles used as an aid to guide
permanent piles to their proper
locations. Falsework piles, which are
removed upon installation of the
permanent piles, are usually steel pipe
piles and are driven and removed using
a vibratory driver. It has not been
determined exactly what parts or how
much of the project will be constructed
in any given year; however, a maximum
of 195 days of pile driving may occur
per in-water work window. The analysis
contained herein is based upon the
maximum of 195 pile driving days,
rather than any specific number of piles
driven. Table 1 summarizes the number
and nature of piles required for the
entire project, rather than what subset of
piles may be expected to be driven
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during the third year of construction
proposed for this IHA.
TABLE 1—SUMMARY OF PILES
REQUIRED FOR WHARF CONSTRUCTION
[in total]
Feature
Total number of permanent
in-water piles.
Size and number of main
wharf piles.
Size and number of warping wharf piles.
Size and number of lightning tower piles.
Size and number of trestle
piles.
Falsework piles ..................
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Maximum pile driving duration.
Quantity
Up to 1,250.
24-in: 140.
36-in: 157.
48-in: 263.
24-in: 80.
36-in: 190.
24-in: 40.
36-in: 90.
24-in: 57.
36-in: 233.
Up to 150, 18to 24-in.
195 days (under
one-year IHA).
Pile installation will utilize vibratory
pile drivers to the greatest extent
possible, and the Navy anticipates that
most piles will be able to be vibratory
driven to within several feet of the
required depth. Pile drivability is, to a
large degree, a function of soil
conditions and the type of pile hammer.
The soil conditions encountered during
geotechnical explorations at NBKB
indicate existing conditions generally
consist of fill or sediment of very dense
glacially overridden soils. Recent
experience at other construction
locations along the NBKB waterfront
indicates that most piles should be able
to be driven with a vibratory hammer to
proper embedment depth. However,
difficulties during pile driving may be
encountered as a result of obstructions,
such as rocks or boulders, which may
exist throughout the project area. If
difficult driving conditions occur,
increased usage of an impact hammer
will occur.
Unless difficult driving conditions are
encountered, an impact hammer will
only be used to proof the load-bearing
capacity of approximately every fourth
or fifth pile. The industry standard is to
proof every pile with an impact
hammer; however, in an effort to reduce
blow counts from the impact hammer,
the engineer of record has agreed to only
proof every fourth or fifth pile. A
maximum of 200 strikes would be
required to proof each pile. Pile
production rates are dependent upon
required embedment depths, the
potential for encountering difficult
driving conditions, and the ability to
drive multiple piles without a need to
relocate the driving rig. Under best-case
scenarios (i.e., shallow piles, driving in
optimal conditions, using multiple
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driving rigs), it may be possible to
install enough pilings with the vibratory
hammer that proofing may be required
for up to five piles in a day. Under this
scenario, with a single impact hammer
used to proof up to five piles per day at
200 strikes per pile, it is estimated that
up to a maximum of 1,000 strikes from
an impact hammer would be required
per day.
If difficult subsurface driving
conditions (e.g., cobble/boulder zones)
are encountered that cause refusal with
the vibratory equipment, it may be
necessary to use an impact hammer to
drive some piles for the remaining
portion of their required depth. The
worst-case scenario is that a pile would
be driven for its entire length using an
impact hammer. Given the uncertainty
regarding the types and quantities of
boulders or cobbles that may be
encountered, and the depth at which
they may be encountered, the number of
strikes necessary to drive a pile its
entire length could be approximately
1,000 to 2,000 strikes per pile. The Navy
estimates that a possible worst-case
daily scenario would require driving
three piles full length (at a worst-case of
2,000 strikes per pile) after the piles
have become hung on large boulders
early in the installation process, with
proofing of an additional two piles (at
200 strikes each) that were able to be
installed primarily via vibratory means.
This worst-case scenario would
therefore result in a maximum of 6,400
strikes per day. All piles driven or
struck with an impact hammer would be
surrounded by a bubble curtain over the
full water column to minimize in-water
sound. Up to three vibratory rigs and
one impact rig may be used at a time.
Pile production rate (number of piles
driven per day) is affected by many
factors: Size, type (vertical versus
angled), and location of piles; weather;
number of driver rigs operating;
equipment reliability; geotechnical
(subsurface) conditions; and work
stoppages for security or environmental
reasons (such as presence of marine
mammals).
Description of Work Accomplished—
During the first in-water work season,
the contractor completed installation of
184 piles to support the main segment
of the access trestle. Driven piles ranged
in size from 24- to 36-in at depths
ranging from 0 to 15 m. A maximum of
two vibratory pile drivers and one
impact hammer were operated
concurrently.
During the second season, installation
of 411 total piles was completed,
including all 315 of the wharf deck
plumb piles (non-fender) and 24 of the
34 total wharf deck Lead Rubber Bearing
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(LRB) dolphins (clusters of four piles
per dolphin). Installed piles ranged in
size from 36- to 48-in at depths ranging
from 12–29 m. As before, a maximum
two vibratory pile drivers and one
impact hammer were operated
concurrently.
During the third season, the Navy
expects to complete installation of the
wharf deck LRBs, piling support for the
warping wharf, lightning towers, and
trestle deck closure as well as all fender
piles. The Navy expects to complete the
project in January 2016. The amount of
progress made under this proposed IHA,
if issued, would determine necessity of
a fourth IHA for the 2015–16 in-water
work window.
Description of Marine Mammals in the
Area of the Specified Activity
There are eight marine mammal
species with recorded occurrence in the
Hood Canal during the past fifteen
years, including five cetaceans and three
pinnipeds. The harbor seal resides yearround in Hood Canal, while the Steller
sea lion and California sea lion inhabit
Hood Canal during portions of the year.
Harbor porpoises may transit through
the project area and occur regularly in
Hood Canal, while transient killer
whales could be present in the project
area but do not have regular occurrence
in the Hood Canal. The Dall’s porpoise
(Phocoenoides dalli dalli), humpback
whale (Megaptera novaeangliae), and
gray whale (Eschrichtius robustus) have
been observed in Hood Canal, but their
presence is sufficiently rare that we do
not believe there is a reasonable
likelihood of their occurrence in the
project area during the proposed period
of validity for this IHA. The latter three
species are not carried forward for
further analysis beyond this section.
We have reviewed the Navy’s detailed
species descriptions, including life
history information, for accuracy and
completeness and refer the reader to
Sections 3 and 4 of the Navy’s
application instead of reprinting the
information here. Please also refer to
NMFS’ Web site (www.nmfs.noaa.gov/
pr/species/mammals) for generalized
species accounts and to the Navy’s
Marine Resource Assessment for the
Pacific Northwest, which documents
and describes the marine resources that
occur in Navy operating areas of the
Pacific Northwest, including Puget
Sound (DoN, 2006). The document is
publicly available at
www.navfac.navy.mil/products_and_
services/ev/products_and_services/
marine_resources/marine_resource_
assessments.html (accessed May 2,
2014).
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Table 2 lists the marine mammal
species with expected potential for
occurrence in the vicinity of NBKB
during the project timeframe and
summarizes key information regarding
stock status and abundance.
Taxonomically, we follow Committee
on Taxonomy (2014). Please see NMFS’
Stock Assessment Reports (SAR),
available at www.nmfs.noaa.gov/pr/sars,
for more detailed accounts of these
stocks’ status and abundance. The
harbor seal, California sea lion and
harbor porpoise are addressed in the
Pacific SARs (e.g., Carretta et al., 2013a),
while the Steller sea lion and transient
killer whale are treated in the Alaska
SARs (e.g., Allen and Angliss, 2013a).
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In the species accounts provided here,
we offer a brief introduction to the
species and relevant stock as well as
available information regarding
population trends and threats, and
describe any information regarding local
occurrence.
TABLE 2—MARINE MAMMALS POTENTIALLY PRESENT IN THE VICINITY OF NBKB
Species
ESA/MMPA
status;
strategic
(Y/N) 1
Stock
Stock abundance (CV,
Nmin, most
recent
abundance
survey) 2
PBR 3
Annual
M/SI 4
Relative occurrence in Hood Canal;
season of occurrence
Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Delphinidae
Killer whale ..............
West coast transient.5 6
—;N ..............
243 (n/a;
2006).
2.4
—;N ..............
10,682
(0.38;
7,841;
2003).
296,750 (n/
a;
153,337;
2008).
63,160–
78,198 (n/
a; 57,966;
2008–
11) 9.
0
Rare; year-round (but last observed in
2005).
Family Phocoenidae (porpoises)
Harbor porpoise .......
Washington inland
waters.7
63
≥2.2
Possible regular presence; year-round.
9,200
≥431
Seasonal/common; Fall to late spring
(Aug to Jun).
10 1,552
65.1
Seasonal/occasional; Fall to late spring
(Sep to May).
771
13.4
Common; Year-round resident.
Order Carnivora—Superfamily Pinnipedia
Family Otariidae (eared seals and sea lions)
California sea lion ....
U.S. .........................
—; N .............
Steller sea lion .........
Eastern U.S.5 ..........
—; N 8 ..........
Family Phocidae (earless seals)
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Harbor seal ..............
Washington inland
waters.7
—; N .............
14,612
(0.15;
12,844;
1999).
1 ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (—) indicates that the species is not listed under the ESA
or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
2 CV is coefficient of variation; N
min is the minimum estimate of stock abundance. In some cases, CV is not applicable. For killer whales, the
abundance values represent direct counts of individually identifiable animals; therefore there is only a single abundance estimate with no associated CV. For certain stocks of pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some
correction factor derived from knowledge of the specie’s (or similar species’) life history to arrive at a best abundance estimate; therefore, there
is no associated CV. In these cases, the minimum abundance may represent actual counts of all animals ashore.
3 Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
4 These values, found in NMFS’ SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a
minimum value. All values presented here are from the draft 2013 SARs (www.nmfs.noaa.gov/pr/sars/draft.htm).
5 Abundance estimates (and resulting PBR values) for these stocks are new values presented in the draft 2013 SARs. This information was
made available for public comment and is currently under review and therefore may be revised prior to finalizing the 2013 SARs. However, we
consider this information to be the best available for use in this document.
6 The abundance estimate for this stock includes only animals from the ‘‘inner coast’’ population occurring in inside waters of southeastern
Alaska, British Columbia, and Washington—excluding animals from the ‘‘outer coast’’ subpopulation, including animals from California—and
therefore should be considered a minimum count. For comparison, the previous abundance estimate for this stock, including counts of animals
from California that are now considered outdated, was 354.
7 Abundance estimates for these stocks are greater than eight years old and are therefore not considered current. PBR is considered undetermined for these stocks, as there is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent
abundance estimates and PBR values, as these represent the best available information for use in this document.
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8 The eastern distinct population segment of the Steller sea lion, previously listed under the ESA as threatened, was delisted on December 4,
2013 (78 FR 66140; November 4, 2013). Because this stock is not below its OSP size and the level of direct human-caused mortality does not
exceed PBR, this delisting action implies that the stock is no longer designated as depleted or as a strategic stock under the MMPA.
9 Best abundance is calculated as the product of pup counts and a factor based on the birth rate, sex and age structure, and growth rate of the
population. A range is presented because the extrapolation factor varies depending on the vital rate parameter resulting in the growth rate (i.e.,
high fecundity or low juvenile mortality).
10 PBR is calculated for the U.S. portion of the stock only (excluding animals in British Columbia) and assumes that the stock is not within its
OSP. If we assume that the stock is within its OSP, PBR for the U.S. portion increases to 2,069.
Although present in Washington
inland waters in small numbers
(Falcone et al., 2005), primarily in the
Strait of Juan de Fuca and San Juan
Islands but also occasionally in Puget
Sound, the humpback whale is not
typically present in Hood Canal.
Archived sighting records show no
confirmed observations from 2001–11
(www.orcanetwork.org; accessed May 5,
2014), and no records are found in the
literature. In January–February 2012,
one individual was observed in Hood
Canal repeatedly over a period of
several weeks. No sightings have been
recorded since that time.
Gray whales generally migrate
southbound past Washington in late
December and January, and transit past
Washington on the northbound return
in March to May. Gray whales do not
generally make use of Washington
inland waters, but have been observed
in certain portions of those waters in all
months of the year, with most records
occurring from March through June
(Calambokidis et al., 2010;
www.orcanetwork.org) and associated
with regular feeding areas. Usually
fewer than twenty gray whales visit the
inner marine waters of Washington and
British Columbia beginning in about
January, and six to ten of these are
individual whales that return most years
to feeding sites in northern Puget
Sound. The remaining individuals
occurring in any given year generally
appear unfamiliar with feeding areas,
often arrive emaciated, and commonly
die of starvation (WDFW, 2012). Gray
whales have been sighted in Hood Canal
on six occasions since 1999 (including
a stranded whale), with the most recent
report in November 2010
(www.orcanetwork.org).
In Washington, Dall’s porpoises are
most abundant in offshore waters where
they are year-round residents, although
interannual distribution is highly
variable (Green et al., 1992). In inland
waters, Dall’s porpoises are most
frequently observed in the Strait of Juan
de Fuca and Haro Strait between San
Juan Island and Vancouver Island
(Nysewander et al., 2005), but are seen
occasionally in southern Puget Sound
and may also occasionally occur in
Hood Canal. Only a single Dall’s
porpoise has been observed at NBKB, in
deeper water during a 2008 summer
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survey conducted by the Navy
(Tannenbaum et al., 2009). On the basis
of this single observation, we previously
assumed it appropriate to authorize
incidental take of this species. However,
there have been no subsequent
observations of Dall’s porpoises in Hood
Canal during either dedicated vessel
line-transect surveys or project-specific
monitoring and we no longer believe
that the species may be reasonably
expected to be present in the action
area.
Steller Sea Lion
Steller sea lions are distributed
mainly around the coasts to the outer
continental shelf along the North Pacific
rim from northern Hokkaido, Japan
through the Kuril Islands and Okhotsk
Sea, Aleutian Islands and central Bering
Sea, southern coast of Alaska and south
to California (Loughlin et al., 1984).
Based on distribution, population
response, and phenotypic and genotypic
data, two separate stocks of Steller sea
lions are recognized within U.S. waters,
with the population divided into
western and eastern distinct population
segments (DPS) at 144°W (Cape
Suckling, Alaska) (Loughlin, 1997). The
eastern DPS extends from California to
Alaska, including the Gulf of Alaska,
and is the only stock that may occur in
the Hood Canal.
According to NMFS’ recent status
review (NMFS, 2013), the best available
information indicates that the overall
abundance of eastern DPS Steller sea
lions has increased for a sustained
period of at least three decades while
pup production has also increased
significantly, especially since the mid1990s. Johnson and Gelatt (2012)
provided an analysis of growth trends of
the entire eastern DPS from 1979–2010,
indicating that the stock increased
during this period at an annual rate of
4.2 percent (90% CI 3.7–4.6). Most of
the overall increase occurred in the
northern portion of the range (southeast
Alaska and British Columbia), but pup
counts in Oregon and California also
increased significantly (e.g., Merrick et
al., 1992; Sease et al., 2001; Olesiuk and
Trites, 2003; Fritz et al. 2008; Olesiuk,
2008; NMFS, 2008, 2013). In
Washington, Pitcher et al. (2007)
reported that Steller sea lions,
presumably immature animals and non-
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breeding adults, regularly used four
haul-outs, including two ‘‘major’’ haulouts (>50 animals). The same study
reported that the numbers of sea lions
counted between 1989 and 2002 on
Washington haul-outs increased
significantly (average annual rate of 9.2
percent) (Pitcher et al., 2007). Although
the stock size has increased, its status
relative to OSP size is unknown.
However, the consistent long-term
estimated annual rate of increase may
indicate that the stock is reaching OSP
size (Allen and Angliss, 2013a).
Data from 2005–10 show a total mean
annual mortality rate of 5.71 (CV = 0.23)
sea lions per year from observed
fisheries and 11.25 reported takes per
year that could not be assigned to
specific fisheries, for an approximate
total from all fisheries of 17 eastern
Steller sea lions (Allen and Angliss,
2013a). In addition, opportunistic
observations and stranding data indicate
that an additional 32 animals are killed
or seriously injured each year through
interaction with commercial and
recreational troll fisheries and by
entanglement (Allen and Angliss,
2013b). The annual average take for
subsistence harvest in Alaska was 11.9
individuals in 2004–08 (Allen and
Angliss, 2013a). Data on community
subsistence harvests is no longer being
collected, and this average is retained as
an estimate for current and future
subsistence harvest. Sea lion deaths are
also known to occur because of illegal
shooting, vessel strikes, or capture in
research gear and other traps, totaling
4.2 animals per year from 2007–11
(Allen and Angliss, 2013b). The total
annual human-caused mortality is a
minimum estimate because takes via
fisheries interactions and subsistence
harvest in Canada are poorly known,
although are believed to be small.
The eastern stock breeds in rookeries
located in southeast Alaska, British
Columbia, Oregon, and California. There
are no known breeding rookeries in
Washington (Allen and Angliss, 2013a)
but eastern stock Steller sea lions are
present year-round along the outer coast
of Washington, including immature
animals or non-breeding adults of both
sexes. In 2011, the minimum count for
Steller sea lions in Washington was
1,749 (Allen and Angliss, 2013b), up
from 516 in 2001 (Pitcher et al., 2007).
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In Washington, Steller sea lions
primarily occur at haul-out sites along
the outer coast from the Columbia River
to Cape Flattery and in inland waters
sites along the Vancouver Island
coastline of the Strait of Juan de Fuca
(Jeffries et al., 2000; Olesiuk and Trites,
2003; Olesiuk, 2008). Numbers vary
seasonally in Washington waters with
peak numbers present during the fall
and winter months (Jeffries et al., 2000).
Beginning in 2008, Steller sea lions have
been observed at NBKB hauled out on
submarines at Delta Pier (located
approximately 1.25 km south of the
project site) during fall through spring
months, with September 26 as the
earliest documented arrival. When
Steller sea lions are present, there are
typically one to four individuals, with a
maximum observed group size of
eleven.
Harbor Seal
Harbor seals inhabit coastal and
estuarine waters and shoreline areas of
the northern hemisphere from temperate
to polar regions. The eastern North
Pacific subspecies is found from Baja
California north to the Aleutian Islands
and into the Bering Sea. Multiple lines
of evidence support the existence of
geographic structure among harbor seal
populations from California to Alaska
(e.g., O’Corry-Crowe et al., 2003; Temte,
1986; Calambokidis et al., 1985; Kelly,
1981; Brown, 1988; Lamont, 1996; Burg,
1996). Harbor seals are generally nonmigratory, and analysis of genetic
information suggests that genetic
differences increase with geographic
distance (Westlake and O’Corry-Crowe,
2002). However, because stock
boundaries are difficult to meaningfully
draw from a biological perspective,
three separate harbor seal stocks are
recognized for management purposes
along the west coast of the continental
U.S.: (1) Inland waters of Washington
(including Hood Canal, Puget Sound,
and the Strait of Juan de Fuca out to
Cape Flattery), (2) outer coast of Oregon
and Washington, and (3) California
(Carretta et al., 2013a). Multiple stocks
are recognized in Alaska. Samples from
Washington, Oregon, and California
demonstrate a high level of genetic
diversity and indicate that the harbor
seals of Washington inland waters
possess unique haplotypes not found in
seals from the coasts of Washington,
Oregon, and California (Lamont et al.,
1996). Only the Washington inland
waters stock may be found in the project
area.
Recent genetic evidence suggests that
harbor seals of Washington inland
waters may have sufficient population
structure to warrant division into
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multiple distinct stocks (Huber et al.,
2010, 2012). Based on studies of
pupping phenology, mitochondrial
DNA, and microsatellite variation,
Carretta et al. (2013b) suggest division
of the Washington inland waters stock
into three new populations, and present
these as prospective stocks: (1) Southern
Puget Sound (south of the Tacoma
Narrows Bridge); (2) Washington
northern inland waters (including Puget
Sound north of the Tacoma Narrows
Bridge, the San Juan Islands, and the
Strait of Juan de Fuca); and (3) Hood
Canal. Until this stock structure is
accepted, we consider a single
Washington inland waters stock.
The best available abundance estimate
was derived from aerial surveys of
harbor seals in Washington conducted
during the pupping season in 1999,
during which time the total numbers of
hauled-out seals (including pups) were
counted (Jeffries et al., 2003). Radiotagging studies conducted at six
locations collected information on
harbor seal haul-out patterns in 1991–
92, resulting in a pooled correction
factor (across three coastal and three
inland sites) of 1.53 to account for
animals in the water which are missed
during the aerial surveys (Huber et al.,
2001), which, coupled with the aerial
survey counts, provides the abundance
estimate (see Table 2).
Harbor seal counts in Washington
State increased at an annual rate of six
percent from 1983–96, increasing to ten
percent for the period 1991–96 (Jeffries
et al., 1997). The population is thought
to be stable, and the Washington inland
waters stock is considered to be within
its OSP size (Jeffries et al., 2003).
Data from 2007–11 indicate that a
minimum of four harbor seals are killed
annually in Washington inland waters
commercial fisheries, while mean
annual mortality for recreational
fisheries is one seal (Carretta et al.,
2013b). Animals captured east of Cape
Flattery are assumed to belong to this
stock. The estimate is considered a
minimum because there are likely
additional animals killed in unobserved
fisheries and because not all animals
stranding as a result of fisheries
interactions are likely to be recorded.
Another 8.4 harbor seals per year are
estimated to be killed as a result of
various non-fisheries human
interactions (Carretta et al., 2013b).
Tribal subsistence takes of this stock
may occur, but no data on recent takes
are available.
Harbor seals are the most abundant
marine mammal in Hood Canal, where
they can occur anywhere year-round
and are considered resident, and are the
only pinniped that breeds in inland
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32833
Washington waters (Jeffries et al., 2003).
They are year-round, non-migratory
residents, pup (i.e., give birth) in Hood
Canal, and the population is considered
closed, meaning that they do not have
much movement outside of Hood Canal
(London, 2006). Surveys in the Hood
Canal from the mid-1970s to 2000 show
a fairly stable population between 600–
1,200 seals, and the abundance of
harbor seals in Hood Canal has likely
stabilized at its carrying capacity of
approximately 1,000 seals (Jeffries et al.,
2003). Harbor seals have been
consistently sighted during Navy
surveys, found in all marine habitats
including nearshore waters and deeper
water, and have been observed hauled
out on manmade objects such as buoys
(Agness and Tannenbaum, 2009;
Tannenbaum et al., 2009, 2011). Harbor
seals were commonly observed in the
water during monitoring conducted for
other projects at NBKB in 2011–13
(HDR, 2012a, 2012b; Hart Crowser,
2013).
There are no known pupping or
regular haul-out sites in the project area,
as harbor seals in Hood Canal prefer
river deltas and exposed tidal areas
(London, 2006). The closest haul-out to
the project area is approximately 16 km
southwest of NBKB at Dosewallips River
mouth, outside the potential area of
effect for this project (see Figure 4–1 of
the Navy’s application). During most of
the year, all age and sex classes (except
neonates) occur in the project area
throughout the period of construction
activity. Because there are no known
regular pupping sites in the vicinity of
the project area, harbor seal neonates
would not generally be expected to be
present during pile driving. However,
pupping has been observed on the
NBKB waterfront at Carderock Pier and
Service Pier (both locations over a mile
south of the project site), and a harbor
seal neonate was observed on a small
floating dock near the project site in
2013.
California Sea Lion
California sea lions range from the
Gulf of California north to the Gulf of
Alaska, with breeding areas located in
the Gulf of California, western Baja
California, and southern California. Five
genetically distinct geographic
populations have been identified: (1)
Pacific temperate, (2) Pacific
subtropical, and (3–5) southern, central,
and northern Gulf of California
(Schramm et al., 2009). Rookeries for
the Pacific temperate population are
found within U.S. waters and just south
of the U.S.-Mexico border, and animals
belonging to this population may be
found from the Gulf of Alaska to
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Mexican waters off Baja California. For
management purposes, a stock of
California sea lions comprising those
animals at rookeries within the U.S. is
defined (i.e., the U.S. stock of California
sea lions) (Carretta et al., 2013a). Pup
production at the Coronado Islands
rookery in Mexican waters is considered
an insignificant contribution to the
overall size of the Pacific temperate
population (Lowry and MaravillaChavez, 2005).
Trends in pup counts from 1975
through 2008 have been assessed for
four rookeries in southern California
and for haul-outs in central and
northern California. During this time
period counts of pups increased at an
annual rate of 5.4 percent, excluding six
El Nino years when pup production
declined dramatically before quickly
rebounding (Carretta et al., 2013a). The
maximum population growth rate was
9.2 percent when pup counts from the
˜
El Nino years were removed. There are
indications that the California sea lion
may have reached or is approaching
carrying capacity, although more data
are needed to confirm that leveling in
growth persists (Carretta et al., 2013a).
Data from 2003–09 indicate that a
minimum of 337 (CV = 0.56) California
sea lions are killed annually in
commercial fisheries. In addition, a
summary of stranding database records
for 2005–09 shows an annual average of
65 such events, which is likely a gross
underestimate because most carcasses
are not recovered. California sea lions
may also be removed because of
predation on endangered salmonids
(seventeen per year, 2008–10) or
incidentally captured during scientific
research (three per year, 2005–09)
(Carretta et al., 2013a). Sea lion
mortality has also been linked to the
algal-produced neurotoxin domoic acid
(Scholin et al., 2000). Future mortality
may be expected to occur, due to the
sporadic occurrence of such harmful
algal blooms. There is currently an
Unusual Mortality Event (UME)
declaration in effect for California sea
lions. Beginning in January 2013,
elevated strandings of California sea
lion pups have been observed in
southern California, with live sea lion
strandings nearly three times higher
than the historical average. Findings to
date indicate that a likely contributor to
the large number of stranded,
malnourished pups was a change in the
availability of sea lion prey for nursing
mothers, especially sardines. The causes
and mechanisms of this UME remain
under investigation
(www.nmfs.noaa.gov/pr/health/
mmume/californiasealions2013.htm;
accessed May 8, 2014).
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An estimated 3,000 to 5,000 California
sea lions migrate northward along the
coast to central and northern California,
Oregon, Washington, and Vancouver
Island during the non-breeding season
from September to May (Jeffries et al.,
2000) and return south the following
spring (Mate, 1975; Bonnell et al., 1983).
Peak numbers of up to 1,000 California
sea lions occur in Puget Sound
(including Hood Canal) during this time
period (Jeffries et al., 2000).
California sea lions are present in
Hood Canal during much of the year
with the exception of mid-June through
August, and occur regularly at NBKB, as
observed during Navy waterfront
surveys conducted from April 2008
through December 2013 (DoN, 2013).
They are known to utilize a diversity of
man-made structures for hauling out
(Riedman, 1990) and, although there are
no regular California sea lion haul-outs
known within the Hood Canal (Jeffries
et al., 2000), they are frequently
observed hauled out at several
opportune areas at NBKB (e.g.,
submarines, floating security fence,
barges). All documented instances of
California sea lions hauling out at NBKB
have been on submarines docked at
Delta Pier, where a maximum of 122
California sea lions have been observed
at any one time (DoN, 2013), and on
pontoons of the NBKB floating security
fence.
Killer Whale
Killer whales are one of the most
cosmopolitan marine mammals, found
in all oceans with no apparent
restrictions on temperature or depth,
although they do occur at higher
densities in colder, more productive
waters at high latitudes and are more
common in nearshore waters
(Leatherwood and Dahlheim, 1978;
Forney and Wade, 2006). Killer whales
are found throughout the North Pacific,
including the entire Alaska coast, in
British Columbia and Washington
inland waterways, and along the outer
coasts of Washington, Oregon, and
California. On the basis of differences in
morphology, ecology, genetics, and
behavior, populations of killer whales
have largely been classified as
‘‘resident’’, ‘‘transient’’, or ‘‘offshore’’
(e.g., Dahlheim et al., 2008). Several
studies have also provided evidence
that these ecotypes are genetically
distinct, and that further genetic
differentiation is present between
subpopulations of the resident and
transient ecotypes (e.g., Barrett-Lennard,
2000). The taxonomy of killer whales is
unresolved, with expert opinion
generally following one of two lines:
Killer whales are either (1) a single
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highly variable species, with locally
differentiated ecotypes representing
recently evolved and relatively
ephemeral forms not deserving species
status, or (2) multiple species,
supported by the congruence of several
lines of evidence for the distinctness of
sympatrically occurring forms (Krahn et
al., 2004). Resident and transient whales
are currently considered to be unnamed
subspecies (Committee on Taxonomy,
2014).
The resident and transient
populations have been divided further
into different subpopulations on the
basis of genetic analyses, distribution,
and other factors. Recognized stocks in
the North Pacific include Alaska
residents; northern residents; southern
residents; Gulf of Alaska, Aleutian
Islands, and Bering Sea transients; and
west coast transients, along with a
single offshore stock. See Allen and
Angliss (2013a) for more detail about
these stocks. West coast transient killer
whales, which occur from California
through southeastern Alaska, are the
only type expected to potentially occur
in the project area.
It is thought that the stock grew
rapidly from the mid-1970s to mid1990s as a result of a combination of
high birth rate, survival, as well as
greater immigration of animals into the
nearshore study area (DFO, 2009). The
rapid growth of the population during
this period coincided with a dramatic
increase in the abundance of the whales’
primary prey, harbor seals, in nearshore
waters. Population growth began
slowing in the mid-1990s and has
continued to slow in recent years (DFO,
2009). Population trends and status of
this stock relative to its OSP level are
currently unknown. Analyses in DFO
(2009) estimated a rate of increase of
about six percent per year from 1975 to
2006, but this included recruitment of
non-calf whales into the population.
Although certain commercial fisheries
are known to have potential for
interaction with killer whales and other
mortality, resulting from shooting, ship
strike, or entanglement, has been of
concern in the past, the estimated level
of human caused mortality and serious
injury is currently considered to be zero
for this stock (Allen and Angliss,
2013a). However, this could represent
an underestimate as regards total
fisheries-related mortality due to a lack
of data concerning marine mammal
interactions in Canadian commercial
fisheries known to have potential for
interaction with killer whales. Any such
interactions are thought to be few in
number (Allen and Angliss, 2013a). No
ship strikes have been reported for this
stock, and shooting of transients is
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thought to be minimal because their diet
is based on marine mammals rather than
fish. There are no reports of a
subsistence harvest of killer whales in
Alaska or Canada.
Transient occurrence in inland waters
appears to peak during August and
September, which is the peak time for
harbor seal pupping, weaning, and postweaning (Baird and Dill, 1995). The
number of transient killer whales in
Washington waters at any one time is
probably fewer than twenty individuals
(Wiles, 2004). In 2003 and 2005, small
groups of transient killer whales (eleven
and six individuals, respectively) were
present in Hood Canal for significant
periods of time (59 and 172 days,
respectively) between the months of
January and July. While present, the
whales preyed on harbor seals in the
subtidal zone of the nearshore marine
and inland marine deeper water habitats
(London, 2006).
Harbor Porpoise
Harbor porpoises are found primarily
in inshore and relatively shallow coastal
waters (<100 m) from Point Barrow
(Alaska) to Point Conception
(California). Various genetic analyses
and investigation of pollutant loads
indicate a low mixing rate for harbor
porpoises along the west coast of North
America and likely fine-scale
geographic structure along an almost
continuous distribution from California
to Alaska (e.g., Calambokidis and
Barlow, 1991; Osmek et al., 1994;
Chivers et al., 2002, 2007). However,
stock boundaries are difficult to draw
because any rigid line is generally
arbitrary from a biological perspective.
On the basis of genetic data and density
discontinuities identified from aerial
surveys, eight stocks have been
identified in the eastern North Pacific,
including northern Oregon/Washington
coastal and inland Washington stocks
(Carretta et al., 2013a). The Washington
inland waters stock includes
individuals found east of Cape Flattery
and is the only stock that may occur in
the project area.
Although long-term harbor porpoise
sightings in southern Puget Sound
declined from the 1940s through the
1990s, sightings and strandings have
increased in Puget Sound and northern
Hood Canal in recent years and harbor
porpoise are now considered to
regularly occur year-round in these
waters (Carretta et al., 2013a). Reasons
for the apparent decline, as well as the
apparent rebound, are unknown. Recent
observations may represent a return to
historical conditions, when harbor
porpoises were considered one of the
most common cetaceans in Puget Sound
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(Scheffer and Slipp, 1948). The status of
harbor porpoises in Washington inland
waters relative to OSP is not known
(Carretta et al., 2013a).
Data from 2005–09 indicate that a
minimum of 2.2 Washington inland
waters harbor porpoises are killed
annually in U.S. commercial fisheries
(Carretta et al., 2013a). Animals
captured in waters east of Cape Flattery
are assumed to belong to this stock. This
estimate is considered a minimum
because the Washington Puget Sound
Region salmon set/drift gillnet fishery
has not been observed since 1994, and
because of a lack of knowledge about
the extent to which harbor porpoise
from U.S. waters frequent the waters of
British Columbia and are, therefore,
subject to fishery-related mortality.
However, harbor porpoise takes in the
salmon drift gillnet fishery are unlikely
to have increased since the fishery was
last observed, when few interactions
were recorded, due to reductions in the
number of participating vessels and
available fishing time. Fishing effort and
catch have declined throughout all
salmon fisheries in the region due to
management efforts to recover ESAlisted salmonids (Carretta et al., 2013a).
In addition, an estimated 0.4 animals
per year are killed by non-fishery
human causes (e.g., ship strike,
entanglement). In 2006, a UME was
declared for harbor porpoises
throughout Oregon and Washington,
and a total of 114 strandings were
reported in 2006–07. The cause of the
UME has not been determined and
several factors, including contaminants,
genetics, and environmental conditions,
are still being investigated (Carretta et
al., 2013a).
Prior to recent construction projects
conducted by the Navy at NBKB, harbor
porpoises were considered to have only
occasional occurrence in the project
area. A single harbor porpoise had been
sighted in deeper water at NBKB during
2010 field observations (Tannenbaum et
al., 2011). However, while
implementing monitoring plans for
work conducted from July–October,
2011, the Navy recorded multiple
sightings of harbor porpoise in the
deeper waters of the project area (HDR,
2012). Following these sightings, the
Navy conducted dedicated line transect
surveys, recording multiple additional
sightings of harbor porpoises, and have
revised local density estimates
accordingly.
Potential Effects of the Specified
Activity on Marine Mammals
This section includes a summary and
discussion of the ways that components
of the specified activity may impact
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32835
marine mammals. This discussion also
includes 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 ‘‘Negligible Impact
Analysis’’ 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. In the following
discussion, we provide general
background information on sound and
marine mammal hearing before
considering potential effects to marine
mammals from sound produced by
vibratory and impact pile driving.
Description of Sound Sources
Sound travels in waves, the basic
components of which are frequency,
wavelength, velocity, and amplitude.
Frequency is the number of pressure
waves that pass by a reference point per
unit of time and is measured in hertz
(Hz) or cycles per second. Wavelength is
the distance between two peaks of a
sound wave; lower frequency sounds
have longer wavelengths than higher
frequency sounds and attenuate
(decrease) more rapidly in shallower
water. Amplitude is the height of the
sound pressure wave or the ‘loudness’
of a sound and is typically measured
using the decibel (dB) scale. A dB is the
ratio between a measured pressure (with
sound) and a reference pressure (sound
at a constant pressure, established by
scientific standards). It is a logarithmic
unit that accounts for large variations in
amplitude; therefore, relatively small
changes in dB ratings correspond to
large changes in sound pressure. When
referring to sound pressure levels (SPLs;
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the sound force per unit area), sound is
referenced in the context of underwater
sound pressure to 1 microPascal (mPa).
One pascal is the pressure resulting
from a force of one newton exerted over
an area of one square meter. The source
level (SL) represents the sound level at
a distance of 1 m from the source
(referenced to 1 mPa). The received level
is the sound level at the listener’s
position. Note that all underwater sound
levels in this document are referenced
to a pressure of 1 mPa and all airborne
sound levels in this document are
referenced to a pressure of 20 mPa.
Root mean square (rms) is the
quadratic mean sound pressure over the
duration of an impulse. Rms is
calculated by squaring all of the sound
amplitudes, averaging the squares, and
then taking the square root of the
average (Urick, 1983). Rms accounts for
both positive and negative values;
squaring the pressures makes all values
positive so that they may be accounted
for in the summation of pressure levels
(Hastings and Popper, 2005). This
measurement is often used in the
context of discussing behavioral effects,
in part because behavioral effects,
which often result from auditory cues,
may be better expressed through
averaged units than by peak pressures.
When underwater objects vibrate or
activity occurs, sound-pressure waves
are created. These waves alternately
compress and decompress the water as
the sound wave travels. Underwater
sound waves radiate in all directions
away from the source (similar to ripples
on the surface of a pond), except in
cases where the source is directional.
The compressions and decompressions
associated with sound waves are
detected as changes in pressure by
aquatic life and man-made sound
receptors such as hydrophones.
Even in the absence of sound from the
specified activity, the underwater
environment is typically loud due to
ambient sound. Ambient sound is
defined as environmental background
sound levels lacking a single source or
point (Richardson et al., 1995), and the
sound level of a region is defined by the
total acoustical energy being generated
by known and unknown sources. These
sources may include physical (e.g.,
waves, earthquakes, ice, atmospheric
sound), biological (e.g., sounds
produced by marine mammals, fish, and
invertebrates), and anthropogenic sound
(e.g., vessels, dredging, aircraft,
construction). A number of sources
contribute to ambient sound, including
the following (Richardson et al., 1995):
• Wind and waves: The complex
interactions between wind and water
surface, including processes such as
breaking waves and wave-induced
bubble oscillations and cavitation, are a
main source of naturally occurring
ambient noise for frequencies between
200 Hz and 50 kHz (Mitson, 1995). In
general, ambient sound levels tend to
increase with increasing wind speed
and wave height. Surf noise becomes
important near shore, with
measurements collected at a distance of
8.5 km from shore showing an increase
of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
• Precipitation: Sound from rain and
hail impacting the water surface can
become an important component of total
noise at frequencies above 500 Hz, and
possibly down to 100 Hz during quiet
times.
• Biological: Marine mammals can
contribute significantly to ambient noise
levels, as can some fish and shrimp. The
frequency band for biological
contributions is from approximately 12
Hz to over 100 kHz.
• Anthropogenic: Sources of ambient
noise related to human activity include
transportation (surface vessels and
aircraft), dredging and construction, oil
and gas drilling and production, seismic
surveys, sonar, explosions, and ocean
acoustic studies. Shipping noise
typically dominates the total ambient
noise for frequencies between 20 and
300 Hz. In general, the frequencies of
anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels
are created, they attenuate rapidly
(Richardson et al., 1995). Sound from
identifiable anthropogenic sources other
than the activity of interest (e.g., a
passing vessel) is sometimes termed
background sound, as opposed to
ambient sound.
The sum of the various natural and
anthropogenic sound sources at any
given location and time—which
comprise ‘‘ambient’’ or ‘‘background’’
sound—depends not only on the source
levels (as determined by current
weather conditions and levels of
biological and shipping activity) but
also on the ability of sound to propagate
through the environment. In turn, sound
propagation is dependent on the
spatially and temporally varying
properties of the water column and sea
floor, and is frequency-dependent. As a
result of the dependence on a large
number of varying factors, ambient
sound levels can be expected to vary
widely over both coarse and fine spatial
and temporal scales. Sound levels at a
given frequency and location can vary
by 10–20 dB from day to day
(Richardson et al., 1995). The result is
that, depending on the source type and
its intensity, sound from the specified
activity may be a negligible addition to
the local environment or could form a
distinctive signal that may affect marine
mammals.
Underwater ambient noise was
measured at approximately 113 dB rms
between 50 Hz and 20 kHz during the
recent TPP project, approximately 1.85
mi from the project area (Illingworth &
Rodkin, 2012). In 2009, the average
broadband ambient underwater noise
levels were measured at 114 dB between
100 Hz and 20 kHz (Slater, 2009). Peak
spectral noise from industrial activity
was noted below the 300 Hz frequency,
with maximum levels of 110 dB noted
in the 125 Hz band. In the 300 Hz to 5
kHz range, average levels ranged
between 83 and 99 dB. Wind-driven
wave noise dominated the background
noise environment at approximately 5
kHz and above, and ambient noise
levels flattened above 10 kHz. Known
sound levels and frequency ranges
associated with anthropogenic sources
similar to those that would be used for
this project are summarized in Table 3.
Details of the source types are described
in the following text.
TABLE 3—REPRESENTATIVE SOUND LEVELS OF ANTHROPOGENIC SOURCES
Frequency range
(Hz)
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Sound source
Small vessels .........................................
Tug docking gravel barge ......................
Vibratory driving of 72-in steel pipe pile
Impact driving of 36-in steel pipe pile ....
Impact driving of 66-in cast-in-steelshell (CISS) pile.
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250–1,000
200–1,000
10–1,500
10–1,500
10–1,500
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151
149
180
195
195
dB
dB
dB
dB
dB
rms
rms
rms
rms
rms
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at
at
at
at
at
1 m ................................
100 m ............................
10 m ..............................
10 m ..............................
10 m ..............................
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Reference
Richardson et al., 1995.
Blackwell and Greene, 2002.
Reyff, 2007.
Laughlin, 2007.
Reviewed in Hastings and Popper,
2005.
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In-water construction activities
associated with the project would
include impact pile driving and
vibratory pile driving. The sounds
produced by these activities fall into
one of two general sound types: Pulsed
and non-pulsed (defined in the
following). The distinction between
these two sound types is important
because they have differing potential to
cause physical effects, particularly with
regard to hearing (e.g., Ward, 1997 in
Southall et al., 2007). Please see
Southall et al., (2007) for an in-depth
discussion of these concepts.
Pulsed sound sources (e.g.,
explosions, gunshots, sonic booms,
impact pile driving) produce signals
that are brief (typically considered to be
less than one second), broadband, atonal
transients (ANSI, 1986; Harris, 1998;
NIOSH, 1998; ISO, 2003; ANSI, 2005)
and occur either as isolated events or
repeated in some succession. Pulsed
sounds are all characterized by a
relatively rapid rise from ambient
pressure to a maximal pressure value
followed by a rapid decay period that
may include a period of diminishing,
oscillating maximal and minimal
pressures, and generally have an
increased capacity to induce physical
injury as compared with sounds that
lack these features.
Non-pulsed sounds can be tonal,
narrowband, or broadband, brief or
prolonged, and may be either
continuous or non-continuous (ANSI,
1995; NIOSH, 1998). Some of these nonpulsed sounds can be transient signals
of short duration but without the
essential properties of pulses (e.g., rapid
rise time). Examples of non-pulsed
sounds include those produced by
vessels, aircraft, machinery operations
such as drilling or dredging, vibratory
pile driving, and active sonar systems
(such as those used by the U.S. Navy).
The duration of such sounds, as
received at a distance, can be greatly
extended in a highly reverberant
environment.
Impact hammers operate by
repeatedly dropping a heavy piston onto
a pile to drive the pile into the substrate.
Sound generated by impact hammers is
characterized by rapid rise times and
high peak levels, a potentially injurious
combination (Hastings and Popper,
2005). Vibratory hammers install piles
by vibrating them and allowing the
weight of the hammer to push them into
the sediment. Vibratory hammers
produce significantly less sound than
impact hammers. Peak SPLs may be 180
dB or greater, but are generally 10 to 20
dB lower than SPLs generated during
impact pile driving of the same-sized
pile (Oestman et al., 2009). Rise time is
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slower, reducing the probability and
severity of injury, and sound energy is
distributed over a greater amount of
time (Nedwell and Edwards, 2002;
Carlson et al., 2005).
Marine Mammal Hearing
Hearing is the most important sensory
modality for marine mammals, and
exposure to sound can have deleterious
effects. To appropriately assess these
potential effects, it is necessary to
understand the frequency ranges marine
mammals are able to hear. Current data
indicate that not all marine mammal
species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok
and Ketten, 1999; Au and Hastings,
2008). To reflect this, Southall et al.
(2007) recommended that marine
mammals be divided into functional
hearing groups based on measured or
estimated hearing ranges on the basis of
available behavioral data, audiograms
derived using auditory evoked potential
techniques, anatomical modeling, and
other data. The lower and/or upper
frequencies for some of these functional
hearing groups have been modified from
those designated by Southall et al.
(2007). The functional groups and the
associated frequencies are indicated
below (note that these frequency ranges
do not necessarily correspond to the
range of best hearing, which varies by
species):
• Low-frequency cetaceans
(mysticetes): Functional hearing is
estimated to occur between
approximately 7 Hz and 30 kHz
(extended from 22 kHz; Watkins, 1986;
Au et al., 2006; Lucifredi and Stein,
2007; Ketten and Mountain, 2009;
Tubelli et al., 2012);
• Mid-frequency cetaceans (larger
toothed whales, beaked whales, and
most delphinids): Functional hearing is
estimated to occur between
approximately 150 Hz and 160 kHz;
• High-frequency cetaceans
(porpoises, river dolphins, and members
of the genera Kogia and
Cephalorhynchus; now considered to
include two members of the genus
Lagenorhynchus on the basis of recent
echolocation data and genetic data
[May-Collado and Agnarsson, 2006;
Kyhn et al. 2009, 2010; Tougaard et al.
2010]): Functional hearing is estimated
to occur between approximately 200 Hz
and 180 kHz; and
• Pinnipeds in water: Functional
hearing is estimated to occur between
approximately 75 Hz to 100 kHz for
Phocidae (true seals) and between 100
Hz and 40 kHz for Otariidae (eared
seals), with the greatest sensitivity
between approximately 700 Hz and 20
kHz. The pinniped functional hearing
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32837
group was modified from Southall et al.
(2007) on the basis of data indicating
that phocid species have consistently
demonstrated an extended frequency
range of hearing compared to otariids,
especially in the higher frequency range
¨
(Hemila et al., 2006; Kastelein et al.,
2009; Reichmuth et al., 2013).
There are five marine mammal
species (two cetacean and three
pinniped [two otariid and one phocid]
species) with expected potential to cooccur with Navy construction activities.
Please refer to Table 2. Of the two
cetacean species that may be present,
the killer whale is classified as a midfrequency cetacean and the harbor
porpoise is classified as a highfrequency cetacean.
Acoustic Effects, Underwater
Potential Effects of Pile Driving
Sound—The effects of sounds from pile
driving might result in one or more of
the following: Temporary or permanent
hearing impairment, non-auditory
physical or physiological effects,
behavioral disturbance, and masking
(Richardson et al., 1995; Gordon et al.,
2004; Nowacek et al., 2007; Southall et
al., 2007). The effects of pile driving on
marine mammals are dependent on
several factors, including the size, type,
and depth of the animal; the depth,
intensity, and duration of the pile
driving sound; the depth of the water
column; the substrate of the habitat; the
standoff distance between the pile and
the animal; and the sound propagation
properties of the environment. Impacts
to marine mammals from pile driving
activities are expected to result
primarily from acoustic pathways. As
such, the degree of effect is intrinsically
related to the received level and
duration of the sound exposure, which
are in turn influenced by the distance
between the animal and the source. The
further away from the source, the less
intense the exposure should be. The
substrate and depth of the habitat affect
the sound propagation properties of the
environment. Shallow environments are
typically more structurally complex,
which leads to rapid sound attenuation.
In addition, substrates that are soft (e.g.,
sand) would absorb or attenuate the
sound more readily than hard substrates
(e.g., rock) which may reflect the
acoustic wave. Soft porous substrates
would also likely require less time to
drive the pile, and possibly less forceful
equipment, which would ultimately
decrease the intensity of the acoustic
source.
In the absence of mitigation, impacts
to marine species would be expected to
result from physiological and behavioral
responses to both the type and strength
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of the acoustic signature (Viada et al.,
2008). The type and severity of
behavioral impacts are more difficult to
define due to limited studies addressing
the behavioral effects of impulsive
sounds on marine mammals. Potential
effects from impulsive sound sources
can range in severity from effects such
as behavioral disturbance or tactile
perception to physical discomfort, slight
injury of the internal organs and the
auditory system, or mortality (Yelverton
et al., 1973).
Hearing Impairment and Other
Physical Effects—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 not recoverable,
or temporary (TTS), in which case the
animal’s hearing threshold would
recover over time (Southall et al., 2007).
Marine mammals depend on acoustic
cues for vital biological functions, (e.g.,
orientation, communication, finding
prey, avoiding predators); thus, TTS
may result in reduced fitness in survival
and reproduction. However, this
depends on the frequency and duration
of TTS, as well as the biological context
in which it occurs. TTS of limited
duration, occurring in a frequency range
that does not coincide with that used for
recognition of important acoustic cues,
would have little to no effect on an
animal’s fitness. Repeated sound
exposure that leads to TTS could cause
PTS. PTS constitutes injury, but TTS
does not (Southall et al., 2007). The
following subsections discuss in
somewhat more detail the possibilities
of TTS, PTS, and non-auditory physical
effects.
Temporary Threshold Shift—TTS is
the mildest form of hearing impairment
that can occur during exposure to a
strong sound (Kryter, 1985). While
experiencing TTS, the hearing threshold
rises, and a sound must be stronger in
order to be heard. In terrestrial
mammals, TTS can last from minutes or
hours to days (in cases of strong TTS).
For sound exposures at or somewhat
above the TTS threshold, hearing
sensitivity in both terrestrial and marine
mammals recovers rapidly after
exposure to the sound ends. Few data
on sound levels and durations necessary
to elicit mild TTS have been obtained
for marine mammals, and none of the
published data concern TTS elicited by
exposure to multiple pulses of sound.
Available data on TTS in marine
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mammals are summarized in Southall et
al. (2007).
Given the available data, the received
level of a single pulse (with no
frequency weighting) might need to be
approximately 186 dB re 1 mPa2-s (i.e.,
186 dB sound exposure level [SEL] or
approximately 221–226 dB p-p [peak])
in order to produce brief, mild TTS.
Exposure to several strong pulses that
each have received levels near 190 dB
rms (175–180 dB SEL) might result in
cumulative exposure of approximately
186 dB SEL and thus slight TTS in a
small odontocete, assuming the TTS
threshold is (to a first approximation) a
function of the total received pulse
energy.
The above TTS information for
odontocetes is derived from studies on
the bottlenose dolphin (Tursiops
truncatus) and beluga whale
(Delphinapterus leucas). There is no
published TTS information for other
species of cetaceans. However,
preliminary evidence from a harbor
porpoise exposed to pulsed sound
suggests that its TTS threshold may
have been lower (Lucke et al., 2009). As
summarized above, data that are now
available imply that TTS is unlikely to
occur unless odontocetes are exposed to
pile driving pulses stronger than 180 dB
re 1 mPa rms.
Permanent Threshold Shift—When
PTS occurs, there is physical damage to
the sound receptors in the ear. In severe
cases, there can be total or partial
deafness, while in other cases the
animal has an impaired ability to hear
sounds in specific frequency ranges
(Kryter, 1985). There is no specific
evidence that exposure to pulses of
sound can cause PTS in any marine
mammal. However, given the possibility
that mammals close to a sound source
might incur TTS, there has been further
speculation about the possibility that
some individuals might incur PTS.
Single or occasional occurrences of mild
TTS are not indicative of permanent
auditory damage, but repeated or (in
some cases) single exposures to a level
well above that causing TTS onset might
elicit PTS.
Relationships between TTS and PTS
thresholds have not been studied in
marine mammals but are assumed to be
similar to those in humans and other
terrestrial mammals. PTS might occur at
a received sound level at least several
decibels above that inducing mild TTS
if the animal were exposed to strong
sound pulses with rapid rise time.
Based on data from terrestrial mammals,
a precautionary assumption is that the
PTS threshold for impulse sounds (such
as pile driving pulses as received close
to the source) is at least 6 dB higher than
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the TTS threshold on a peak-pressure
basis and probably greater than 6 dB
(Southall et al., 2007). On an SEL basis,
Southall et al. (2007) estimated that
received levels would need to exceed
the TTS threshold by at least 15 dB for
there to be risk of PTS. Thus, for
cetaceans, Southall et al. (2007) estimate
that the PTS threshold might be an Mweighted SEL (for the sequence of
received pulses) of approximately 198
dB re 1 mPa2-s (15 dB higher than the
TTS threshold for an impulse). Given
the higher level of sound necessary to
cause PTS as compared with TTS, it is
considerably less likely that PTS could
occur.
Measured source levels from impact
pile driving can be as high as 214 dB
rms. Although no marine mammals
have been shown to experience TTS or
PTS as a result of being exposed to pile
driving activities, captive bottlenose
dolphins and beluga whales exhibited
changes in behavior when exposed to
strong pulsed sounds (Finneran et al.,
2000, 2002, 2005). The animals tolerated
high received levels of sound before
exhibiting aversive behaviors.
Experiments on a beluga whale showed
that exposure to a single watergun
impulse at a received level of 207 kPa
(30 psi) p-p, which is equivalent to 228
dB 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 four minutes of the exposure
(Finneran et al., 2002). 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 sound
exposure in terms of SEL than from the
single watergun impulse (estimated at
188 dB re 1 mPa2-s) in the
aforementioned experiment (Finneran et
al., 2002). However, in order for marine
mammals to experience TTS or PTS, the
animals have to be close enough to be
exposed to high intensity sound levels
for a prolonged period of time. Based on
the best scientific information available,
these SPLs are far below the thresholds
that could cause TTS or the onset of
PTS.
Non-auditory Physiological Effects—
Non-auditory physiological effects or
injuries that theoretically might occur in
marine mammals exposed to strong
underwater sound include stress,
neurological effects, bubble formation,
resonance effects, and other types of
organ or tissue damage (Cox et al., 2006;
Southall et al., 2007). Studies examining
such effects are limited. In general, little
is known about the potential for pile
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driving to cause auditory impairment or
other physical effects in marine
mammals. Available data suggest that
such effects, if they occur at all, would
presumably be limited to short distances
from the sound source and to activities
that extend over a prolonged period.
The available data do not allow
identification of a specific exposure
level above which non-auditory effects
can be expected (Southall et al., 2007)
or any meaningful quantitative
predictions of the numbers (if any) of
marine mammals that might be affected
in those ways. Marine mammals that
show behavioral avoidance of pile
driving, including some odontocetes
and some pinnipeds, are especially
unlikely to incur auditory impairment
or non-auditory physical effects.
Disturbance Reactions
Disturbance includes a variety of
effects, including subtle changes in
behavior, more conspicuous changes in
activities, and displacement. Behavioral
responses to sound are highly variable
and context-specific and reactions, if
any, depend on species, state of
maturity, experience, current activity,
reproductive state, auditory sensitivity,
time of day, and many other factors
(Richardson et al., 1995; Wartzok et al.,
2003; Southall et al., 2007).
Habituation can occur when an
animal’s response to a stimulus wanes
with repeated exposure, usually in the
absence of unpleasant associated events
(Wartzok et al., 2003). Animals are most
likely to habituate to sounds that are
predictable and unvarying. The opposite
process is sensitization, when an
unpleasant experience leads to
subsequent responses, often in the form
of avoidance, at a lower level of
exposure. Behavioral state may affect
the type of response as well. For
example, animals that are resting may
show greater behavioral change in
response to disturbing sound levels than
animals that are highly motivated to
remain in an area for feeding
(Richardson et al., 1995; NRC, 2003;
Wartzok et al., 2003).
Controlled experiments with captive
marine mammals showed pronounced
behavioral reactions, including
avoidance of loud sound sources
(Ridgway et al., 1997; Finneran et al.,
2003). Observed responses of wild
marine mammals to loud pulsed sound
sources (typically seismic guns or
acoustic harassment devices, but also
including pile driving) have been varied
but often consist of avoidance behavior
or other behavioral changes suggesting
discomfort (Morton and Symonds, 2002;
Thorson and Reyff, 2006; see also
Gordon et al., 2004; Wartzok et al.,
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2003; Nowacek et al., 2007). Responses
to continuous sound, such as vibratory
pile installation, have not been
documented as well as responses to
pulsed sounds.
With both types of pile driving, it is
likely that the onset of pile driving
could result in temporary, short term
changes in an animal’s typical behavior
and/or avoidance of the affected area.
These behavioral changes may include
(Richardson et al., 1995): Changing
durations of surfacing and dives,
number of blows per surfacing, or
moving direction and/or speed;
reduced/increased vocal activities;
changing/cessation of certain behavioral
activities (such as socializing or
feeding); visible startle response or
aggressive behavior (such as tail/fluke
slapping or jaw clapping); avoidance of
areas where sound sources are located;
and/or flight responses (e.g., pinnipeds
flushing into water from haul-outs or
rookeries). Pinnipeds may increase their
haul-out time, possibly to avoid inwater disturbance (Thorson and Reyff,
2006).
The biological significance of many of
these behavioral disturbances is difficult
to predict, especially if the detected
disturbances appear minor. However,
the consequences of behavioral
modification could be expected to be
biologically significant if the change
affects growth, survival, or
reproduction. Significant behavioral
modifications that could potentially
lead to effects on growth, survival, or
reproduction include:
• Drastic changes in diving/surfacing
patterns (such as those thought to cause
beaked whale stranding due to exposure
to military mid-frequency tactical
sonar);
• Habitat abandonment due to loss of
desirable acoustic environment; and
• Cessation of feeding or social
interaction.
The onset of behavioral disturbance
from anthropogenic sound depends on
both external factors (characteristics of
sound sources and their paths) and the
specific characteristics of the receiving
animals (hearing, motivation,
experience, demography) and is difficult
to predict (Southall et al., 2007).
Auditory Masking
Natural and artificial sounds can
disrupt behavior by masking, or
interfering with, a marine mammal’s
ability to hear other sounds. Masking
occurs when the receipt of a sound is
interfered with by another coincident
sound at similar frequencies and at
similar or higher levels. Chronic
exposure to excessive, though not highintensity, sound could cause masking at
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particular frequencies for marine
mammals that utilize sound for vital
biological functions. Masking can
interfere with detection of acoustic
signals such as communication calls,
echolocation sounds, and
environmental sounds important to
marine mammals. Therefore, under
certain circumstances, marine mammals
whose acoustical sensors or
environment are being severely masked
could also be impaired from maximizing
their performance fitness in survival
and reproduction. If the coincident
(masking) sound were man-made, it
could be potentially harassing if it
disrupted hearing-related behavior. It is
important to distinguish TTS and PTS,
which persist after the sound exposure,
from masking, which occurs during the
sound exposure. Because masking
(without resulting in TS) is not
associated with abnormal physiological
function, it is not considered a
physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially
masking sound is important in
determining any potential behavioral
impacts. Because sound generated from
in-water pile driving is mostly
concentrated at low frequency ranges, it
may have less effect on high frequency
echolocation sounds made by porpoises.
However, lower frequency man-made
sounds are more likely to affect
detection of communication calls and
other potentially important natural
sounds such as surf and prey sound. It
may also affect communication signals
when they occur near the sound band
and thus reduce the communication
space of animals (e.g., Clark et al., 2009)
and cause increased stress levels (e.g.,
Foote et al., 2004; Holt et al., 2009).
Masking has the potential to impact
species at the population or community
levels as well as at individual levels.
Masking affects both senders and
receivers of the signals and can
potentially have long-term chronic
effects on marine mammal species and
populations. Recent research suggests
that low frequency ambient sound levels
have increased by as much as 20 dB
(more than three times in terms of SPL)
in the world’s ocean from pre-industrial
periods, and that most of these increases
are from distant shipping (Hildebrand,
2009). All anthropogenic sound sources,
such as those from vessel traffic, pile
driving, and dredging activities,
contribute to the elevated ambient
sound levels, thus intensifying masking.
The most intense underwater sounds
in the proposed action are those
produced by impact pile driving. Given
that the energy distribution of pile
driving covers a broad frequency
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spectrum, sound from these sources
would likely be within the audible
range of marine mammals present in the
project area. Impact pile driving activity
is relatively short-term, with rapid
pulses occurring for approximately
fifteen minutes per pile. The probability
for impact pile driving resulting from
this proposed action masking acoustic
signals important to the behavior and
survival of marine mammal species is
likely to be negligible. Vibratory pile
driving is also relatively short-term,
with rapid oscillations occurring for
approximately one and a half hours per
pile. It is possible that vibratory pile
driving resulting from this proposed
action may mask acoustic signals
important to the behavior and survival
of marine mammal species, but the
short-term duration and limited affected
area would result in insignificant
impacts from masking. Any masking
event that could possibly rise to Level
B harassment under the MMPA would
occur concurrently within the zones of
behavioral harassment already
estimated for vibratory and impact pile
driving, and which have already been
taken into account in the exposure
analysis.
Acoustic Effects, Airborne
Marine mammals that occur in the
project area could be exposed to
airborne sounds associated with pile
driving that have the potential to cause
harassment, depending on their distance
from pile driving activities. Airborne
pile driving sound would have less
impact on cetaceans than pinnipeds
because sound from atmospheric
sources does not transmit well
underwater (Richardson et al., 1995);
thus, airborne sound would only be an
issue for pinnipeds either hauled-out or
looking with heads above water in the
project area. Most likely, airborne sound
would cause behavioral responses
similar to those discussed above in
relation to underwater sound. For
instance, anthropogenic sound could
cause hauled-out pinnipeds to exhibit
changes in their normal behavior, such
as reduction in vocalizations, or cause
them to temporarily abandon their
habitat and move further from the
source. Studies by Blackwell et al.
(2004) and Moulton et al. (2005)
indicate a tolerance or lack of response
to unweighted airborne sounds as high
as 112 dB peak and 96 dB rms.
Anticipated Effects on Habitat
The proposed activities at NBKB
would not result in permanent impacts
to habitats used directly by marine
mammals, such as haul-out sites, but
may have potential short-term impacts
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to food sources such as forage fish and
salmonids. There are no rookeries or
major haul-out sites within 16 km or
ocean bottom structure of significant
biological importance to marine
mammals that may be present in the
marine waters in the vicinity of the
project area. Therefore, the main impact
associated with the proposed activity
would be temporarily elevated sound
levels and the associated direct effects
on marine mammals, as discussed
previously in this document. The most
likely impact to marine mammal habitat
occurs from pile driving effects on likely
marine mammal prey (i.e., fish) near
NBKB and minor impacts to the
immediate substrate during installation
and removal of piles during the wharf
construction project.
Pile Driving Effects on Potential Prey
Construction activities would produce
both pulsed (i.e., impact pile driving)
and continuous (i.e., vibratory pile
driving) sounds. Fish react to sounds
which are especially strong and/or
intermittent low-frequency sounds.
Short duration, sharp sounds can cause
overt or subtle changes in fish behavior
and local distribution. Hastings and
Popper (2005) identified several studies
that suggest fish may relocate to avoid
certain areas of sound energy.
Additional studies have documented
effects of pile driving on fish, although
several are based on studies in support
of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001,
2002; Popper and Hastings, 2009).
Sound pulses at received levels of 160
dB may cause subtle changes in fish
behavior. SPLs of 180 dB may cause
noticeable changes in behavior (Pearson
et al., 1992; Skalski et al., 1992). SPLs
of sufficient strength have been known
to cause injury to fish and fish
mortality. The most likely impact to fish
from pile driving activities at the project
area would be temporary behavioral
avoidance of the area. The duration of
fish avoidance of this area after pile
driving stops is unknown, but a rapid
return to normal recruitment,
distribution and behavior is anticipated.
In general, impacts to marine mammal
prey species are expected to be minor
and temporary due to the short
timeframe for the wharf construction
project. However, adverse impacts may
occur to a few species of rockfish and
salmon which may still be present in
the project area despite operating in a
reduced work window in an attempt to
avoid important fish spawning time
periods. Impacts to these species could
result from potential impacts to their
eggs and larvae.
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Pile Driving Effects on Potential
Foraging Habitat
The area likely impacted by the
project is relatively small compared to
the available habitat in the Hood Canal.
Avoidance by potential prey (i.e., fish)
of the immediate area due to the
temporary loss of this foraging habitat is
also possible. The duration of fish
avoidance of this area after pile driving
stops is unknown, but a rapid return to
normal recruitment, distribution and
behavior is anticipated. Any behavioral
avoidance by fish of the disturbed area
would still leave significantly large
areas of fish and marine mammal
foraging habitat in the Hood Canal and
nearby vicinity.
In summary, given the short daily
duration of sound associated with
individual pile driving events and the
relatively small areas being affected,
pile driving activities associated with
the proposed action are not likely to
have a permanent, adverse effect on any
fish habitat, or populations of fish
species. Thus, any impacts to marine
mammal habitat are not expected to
cause significant or long-term
consequences for individual marine
mammals or their populations.
Proposed Mitigation
In order to issue an IHA under
Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible
methods of taking pursuant to such
activity, and other means of effecting
the least practicable impact on such
species or stock and its habitat, paying
particular attention to rookeries, mating
grounds, and areas of similar
significance, and on the availability of
such species or stock for taking for
certain subsistence uses.
Measurements from similar pile
driving events were coupled with
practical spreading loss to estimate
zones of influence (ZOI; see ‘‘Estimated
Take by Incidental Harassment’’). These
values were then refined based on in
situ measurements performed during
the TPP, for similar pile driving activity
and within the EHW–2 project footprint,
to develop mitigation measures for
EHW–2 pile driving activities. The ZOIs
effectively represent the mitigation zone
that would be established around each
pile to prevent Level A harassment to
marine mammals, while providing
estimates of the areas within which
Level B harassment might occur. While
the ZOIs vary between the different
diameter piles and types of installation
methods, the Navy is proposing to
establish mitigation zones for the
maximum ZOI for all pile driving
conducted in support of the wharf
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construction project. In addition to the
measures described later in this section,
the Navy would employ the following
standard mitigation measures:
(a) Conduct briefings between
construction supervisors and crews,
marine mammal monitoring team, and
Navy staff prior to the start of all pile
driving activity, and when new
personnel join the work, in order to
explain responsibilities, communication
procedures, marine mammal monitoring
protocol, and operational procedures.
(b) For in-water heavy machinery
work other than pile driving (using, e.g.,
standard barges, tug boats, bargemounted excavators, or clamshell
equipment used to place or remove
material), if a marine mammal comes
within 10 m, operations shall cease and
vessels shall reduce speed to the
minimum level required to maintain
steerage and safe working conditions.
This type of work could include the
following activities: (1) Movement of the
barge to the pile location; (2) positioning
of the pile on the substrate via a crane
(i.e., stabbing the pile); (3) removal of
the pile from the water column/
substrate via a crane (i.e., deadpull); or
(4) the placement of sound attenuation
devices around the piles. For these
activities, monitoring would take place
from 15 minutes prior to initiation until
the action is complete.
Monitoring and Shutdown for Pile
Driving
The following measures would apply
to the Navy’s mitigation through
shutdown and disturbance zones:
Shutdown Zone—For all pile driving
activities, the Navy will establish a
shutdown zone intended to contain the
area in which SPLs equal or exceed the
180/190 dB rms acoustic injury criteria.
The purpose of a shutdown zone is to
define an area within which shutdown
of activity would occur upon sighting of
a marine mammal (or in anticipation of
an animal entering the defined area),
thus preventing injury of marine
mammals. Modeled distances for
shutdown zones are shown in Table 8.
However, during impact pile driving,
the Navy would implement a minimum
shutdown zone of 85 m radius for
cetaceans and 20 m radius for pinnipeds
around all pile driving activity. The
modeled injury threshold distances are
approximately 22 m and 5 m,
respectively, but the distances are
increased based on in-situ recorded
sound pressure levels during the TPP.
During vibratory driving, the shutdown
zone would be 10 m distance from the
source for all animals. These
precautionary measures are intended to
further reduce any possibility of
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acoustic injury, as well as to account for
any undue reduction in the modeled
zones stemming from the assumption of
10 dB attenuation from use of a bubble
curtain (see discussion later in this
section).
Disturbance Zone—Disturbance zones
are the areas in which SPLs equal or
exceed 160 and 120 dB rms (for pulsed
and non-pulsed continuous sound,
respectively). Disturbance zones provide
utility for monitoring conducted for
mitigation purposes (i.e., shutdown
zone monitoring) by establishing
monitoring protocols for areas adjacent
to the shutdown zones. Monitoring of
disturbance zones enables observers to
be aware of and communicate the
presence of marine mammals in the
project area but outside the shutdown
zone and thus prepare for potential
shutdowns of activity. However, the
primary purpose of disturbance zone
monitoring is for documenting incidents
of Level B harassment; disturbance zone
monitoring is discussed in greater detail
later (see ‘‘Proposed Monitoring and
Reporting’’). Nominal radial distances
for disturbance zones are shown in
Table 8. Given the size of the
disturbance zone for vibratory pile
driving, it is impossible to guarantee
that all animals would be observed or to
make comprehensive observations of
fine-scale behavioral reactions to sound,
and only a portion of the zone (e.g.,
what may be reasonably observed by
visual observers stationed within the
water front restricted area [WRA]) will
be monitored.
In order to document observed
incidents of harassment, monitors
record all marine mammal observations,
regardless of location. The observer’s
location, as well as the location of the
pile being driven, is known from a GPS.
The location of the animal is estimated
as a distance from the observer, which
is then compared to the location from
the pile. The received level may be
estimated on the basis of past or
subsequent acoustic monitoring. It may
then be determined whether the animal
was exposed to sound levels
constituting incidental harassment in
post-processing of observational data,
and a precise accounting of observed
incidents of harassment created.
Therefore, although the predicted
distances to behavioral harassment
thresholds are useful for estimating
harassment for purposes of authorizing
levels of incidental take, actual take may
be determined in part through the use
of empirical data. That information may
then be used to extrapolate observed
takes to reach an approximate
understanding of actual total takes.
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Monitoring Protocols—Monitoring
would be conducted before, during, and
after pile driving activities. In addition,
observers shall record all incidents of
marine mammal occurrence, regardless
of distance from activity, and shall
document any behavioral reactions in
concert with distance from piles being
driven. Observations made outside the
shutdown zone will not result in
shutdown; that pile segment would be
completed without cessation, unless the
animal approaches or enters the
shutdown zone, at which point all pile
driving activities would be halted.
Monitoring will take place from fifteen
minutes prior to initiation through
thirty minutes post-completion of pile
driving activities. Pile driving activities
include the time to remove a single pile
or series of piles, as long as the time
elapsed between uses of the pile driving
equipment is no more than thirty
minutes. Please see the Marine Mammal
Monitoring Plan (available at
www.nmfs.noaa.gov/pr/permits/
incidental.htm), developed by the Navy
with our approval, for full details of the
monitoring protocols.
The following additional measures
apply to visual monitoring:
(1) Monitoring will be conducted by
qualified observers, who will be placed
at the best vantage point(s) practicable
to monitor for marine mammals and
implement shutdown/delay procedures
when applicable by calling for the
shutdown to the hammer operator.
Qualified observers are trained
biologists, with the following minimum
qualifications:
• Visual acuity in both eyes
(correction is permissible) sufficient for
discernment of moving targets at the
water’s surface with ability to estimate
target size and distance; use of
binoculars may be necessary to correctly
identify the target;
• Advanced education in biological
science or related field (undergraduate
degree or higher required);
• Experience and ability to conduct
field observations and collect data
according to assigned protocols (this
may include academic experience);
• Experience or training in the field
identification of marine mammals,
including the identification of
behaviors;
• Sufficient training, orientation, or
experience with the construction
operation to provide for personal safety
during observations;
• Writing skills sufficient to prepare a
report of observations including but not
limited to the number and species of
marine mammals observed; dates and
times when in-water construction
activities were conducted; dates and
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times when in-water construction
activities were suspended to avoid
potential incidental injury from
construction sound of marine mammals
observed within a defined shutdown
zone; and marine mammal behavior;
and
• Ability to communicate orally, by
radio or in person, with project
personnel to provide real-time
information on marine mammals
observed in the area as necessary.
(2) Prior to the start of pile driving
activity, the shutdown zone will be
monitored for fifteen minutes to ensure
that it is clear of marine mammals. Pile
driving will only commence once
observers have declared the shutdown
zone clear of marine mammals; animals
will be allowed to remain in the
shutdown zone (i.e., must leave of their
own volition) and their behavior will be
monitored and documented. The
shutdown zone may only be declared
clear, and pile driving started, when the
entire shutdown zone is visible (i.e.,
when not obscured by dark, rain, fog,
etc.). In addition, if such conditions
should arise during impact pile driving
that is already underway, the activity
would be halted.
(3) If a marine mammal approaches or
enters the shutdown zone during the
course of pile driving operations,
activity will be halted and delayed until
either the animal has voluntarily left
and been visually confirmed beyond the
shutdown zone or fifteen minutes have
passed without re-detection of the
animal. Monitoring will be conducted
throughout the time required to drive a
pile.
Sound Attenuation Devices
Sound levels can be greatly reduced
during impact pile driving using sound
attenuation devices. There are several
types of sound attenuation devices
including bubble curtains, cofferdams,
and isolation casings (also called
temporary noise attenuation piles
[TNAP]), and cushion blocks. The Navy
proposes to use bubble curtains, which
create a column of air bubbles rising
around a pile from the substrate to the
water surface. The air bubbles absorb
and scatter sound waves emanating
from the pile, thereby reducing the
sound energy. Bubble curtains may be
confined or unconfined. An unconfined
bubble curtain may consist of a ring
seated on the substrate and emitting air
bubbles from the bottom. An
unconfined bubble curtain may also
consist of a stacked system, that is, a
series of multiple rings placed at the
bottom and at various elevations around
the pile. Stacked systems may be more
effective than non-stacked systems in
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areas with high current and deep water
(Oestman et al., 2009).
A confined bubble curtain contains
the air bubbles within a flexible or rigid
sleeve made from plastic, cloth, or pipe.
Confined bubble curtains generally offer
higher attenuation levels than
unconfined curtains because they may
physically block sound waves and they
prevent air bubbles from migrating away
from the pile. For this reason, the
confined bubble curtain is commonly
used in areas with high current velocity
(Oestman et al., 2009).
Both environmental conditions and
the characteristics of the sound
attenuation device may influence the
effectiveness of the device. According to
Oestman et al. (2009):
• In general, confined bubble curtains
attain better sound attenuation levels in
areas of high current than unconfined
bubble curtains. If an unconfined device
is used, high current velocity may
sweep bubbles away from the pile,
resulting in reduced levels of sound
attenuation.
• Softer substrates may allow for a
better seal for the device, preventing
leakage of air bubbles and escape of
sound waves. This increases the
effectiveness of the device. Softer
substrates also provide additional
attenuation of sound traveling through
the substrate.
• Flat bottom topography provides a
better seal, enhancing effectiveness of
the sound attenuation device, whereas
sloped or undulating terrain reduces or
eliminates its effectiveness.
• Air bubbles must be close to the
pile; otherwise, sound may propagate
into the water, reducing the
effectiveness of the device.
• Harder substrates may transmit
ground-borne sound and propagate it
into the water column.
The literature presents a wide array of
observed attenuation results for bubble
curtains (e.g., Oestman et al., 2009;
Coleman, 2011; see Table 6–5 of the
Navy’s application). The variability in
attenuation levels is due to variation in
design, as well as differences in site
conditions and difficulty in properly
installing and operating in-water
attenuation devices. As a general rule,
reductions of greater than 10 dB cannot
be reliably predicted. The TPP reported
a range of measured values for realized
attenuation mostly within 6 to 12 dB
(Illingworth & Rodkin, 2012). For 36-in
piles the average peak and rms
reduction with use of the bubble curtain
was 8 dB, where the averages of all
bubble-on and bubble-off data were
compared. For 48-in piles, the average
SPL reduction with use of a bubble
curtain was 6 dB for average peak values
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and 5 dB for rms values. See Tables 6–
6 and 6–7 of the Navy’s application.
To avoid loss of attenuation from
design and implementation errors, the
Navy has required specific bubble
curtain design specifications, including
testing requirements for air pressure and
flow prior to initial impact hammer use,
and a requirement for placement on the
substrate. We considered TPP
measurements (approximately 7 dB
overall) and other monitored projects
(typically at least 8 dB realized
attenuation), and consider 8 dB as
potentially the best estimate of average
SPL (rms) reduction, assuming
appropriate deployment and no
problems with the equipment. In
looking at other monitored projects
prior to completion of the TPP, the Navy
determined with our concurrence that
an assumption of 10 dB realized
attenuation was realistic. Therefore, a 10
dB reduction was used in the Navy’s
analysis of pile driving noise in the
initial environmental analyses for the
EHW–2 project. The Navy’s analysis is
retained here. While acknowledging that
empirical evidence from the TPP
indicates that the 10 dB target has not
been consistently achieved, we did not
require the Navy to revisit their acoustic
modeling because (1) shutdown and
disturbance zones for the second and
third construction years are based on in
situ measurements rather than the
original modeling that assumed 10 dB
attenuation from a bubble curtain and
(2) take estimates are not affected
because they are based on a combined
modeled sound field (i.e., concurrent
operation of impact and vibratory
drivers) rather than there being separate
take estimates for impact and vibratory
pile driving.
Bubble curtains shall be used during
all impact pile driving. The device will
distribute air bubbles around 100
percent of the piling perimeter for the
full depth of the water column, and the
lowest bubble ring shall be in contact
with the mudline for the full
circumference of the ring. Testing of the
device by comparing attenuated and
unattenuated strikes is not possible
because of requirements in place to
protect marbled murrelets (an ESAlisted bird species under the jurisdiction
of the USFWS). However, in order to
avoid loss of attenuation from design
and implementation errors in the
absence of such testing, a performance
test of the device shall be conducted
prior to initial use. The performance test
shall confirm the calculated pressures
and flow rates at each manifold ring. In
addition, the contractor shall also train
personnel in the proper balancing of air
flow to the bubblers and shall submit an
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inspection/performance report to the
Navy within 72 hours following the
performance test.
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Timing Restrictions
In Hood Canal, designated timing
restrictions exist for pile driving
activities to avoid in-water work when
salmonids and other spawning forage
fish are likely to be present. The inwater work window is July 16–February
15. Until September 23, impact pile
driving will only occur starting two
hours after sunrise and ending two
hours before sunset due to marbled
murrelet nesting season. After
September 23, in-water construction
activities will occur during daylight
hours (sunrise to sunset).
Soft Start
The use of a soft-start procedure is
believed to provide additional
protection to marine mammals by
warning or providing a chance to leave
the area prior to the hammer operating
at full capacity, and typically involves
a requirement to initiate sound from
vibratory hammers for fifteen seconds at
reduced energy followed by a thirtysecond waiting period. This procedure
is repeated two additional times.
However, implementation of soft start
for vibratory pile driving during
previous pile driving work for the
EHW–2 project at NBKB has led to
equipment failure and serious human
safety concerns. Project staff have
reported that, during power down from
the soft start, the energy from the
hammer is transferred to the crane boom
and block via the load fall cables and
rigging resulting in unexpected damage
to both the crane block and crane boom.
This differs from what occurs when the
hammer is powered down after a pile is
driven to refusal in that the rigging and
load fall cables are able to be slacked
prior to powering down the hammer,
and the vibrations are transferred into
the substrate via the pile rather than
into the equipment via the rigging. One
dangerous incident of equipment failure
has already occurred, with a portion of
the equipment shearing from the crane
and falling to the deck. Subsequently,
the crane manufacturer has inspected
the crane booms and discovered
structural fatigue in the boom lacing and
main structural components, which will
ultimately result in a collapse of the
crane boom. All cranes were new at the
beginning of the job. In addition, the
vibratory hammer manufacturer has
attempted to install dampers to mitigate
the problem, without success.
It is the Navy’s contention that this
situation is unique to the EHW–2
project, in comparison with other
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common marine construction projects
requiring pile driving. The design
specifications of the wharf, which
require relatively large-diameter piles to
be driven to embedment in relatively
deep water through stiff glacial soil,
mean that relatively greater driving
energy, and therefore a larger hammer,
is required for successful embedment.
The Marine Mammal Commission
previously recommended that we
require the Navy to consult with the
Washington State Department of
Transportation and/or the California
Department of Transportation to
determine whether soft start procedures
can be used safely with the vibratory
hammers that the Navy plans to use. We
agreed with that recommendation and
are still working to facilitate such a
consultation in order to determine
whether the potentially significant
human safety issue is inherent to
implementation of the measure or is due
to operator error. However, our interest
in examining this issue is related to our
need to understand the conditions
under which vibratory soft start may be
advisable from an engineering
perspective for future projects.
For this proposed IHA and for the
remainder of the EHW–2 project, as a
result of this potential risk to human
safety, we have determined vibratory
soft start to not currently be practicable.
Therefore, the measure will not be
required. We have further determined
this measure unnecessary to providing
the means of effecting the least
practicable impact on marine mammals
and their habitat.
For impact driving, soft start will be
required, and contractors will provide
an initial set of strikes from the impact
hammer at reduced energy, followed by
a thirty-second waiting period, then two
subsequent reduced energy strike sets.
The reduced energy of an individual
hammer cannot be quantified because of
variation in individual drivers. The
actual number of strikes at reduced
energy will vary because operating the
hammer at less than full power results
in ‘‘bouncing’’ of the hammer as it
strikes the pile, resulting in multiple
‘‘strikes.’’ Soft start for impact driving
will be required at the beginning of each
day’s pile driving work and at any time
following a cessation of impact pile
driving of thirty minutes or longer.
We have carefully evaluated the
Navy’s proposed mitigation measures
and considered their effectiveness in
past implementation to preliminarily
determine whether they are likely to
effect the least practicable impact on the
affected marine mammal species and
stocks and their habitat. Our evaluation
of potential measures included
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consideration of the following factors in
relation to one another: (1) The manner
in which, and the degree to which, the
successful implementation of the
measure is expected to minimize
adverse impacts to marine mammals, (2)
the proven or likely efficacy of the
specific measure to minimize adverse
impacts as planned; and (3) the
practicability of the measure for
applicant implementation.
Any mitigation measure(s) we
prescribe 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 number (total
number or number at biologically
important time or location) of
individual marine mammals exposed to
stimuli expected to result in incidental
take (this goal may contribute to 1,
above, or to reducing takes by
behavioral harassment only).
(3) A reduction in the number (total
number or number at biologically
important time or location) of times any
individual marine mammal would be
exposed to stimuli expected to result in
incidental take (this goal may contribute
to 1, above, or to reducing takes by
behavioral harassment only).
(4) A reduction in the intensity of
exposure to stimuli expected to result in
incidental take (this goal may contribute
to 1, above, or to reducing the severity
of behavioral harassment only).
(5) Avoidance or minimization of
adverse effects to marine mammal
habitat, paying particular attention to
the prey base, blockage or limitation of
passage to or from biologically
important areas, permanent destruction
of habitat, or temporary 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 Navy’s
proposed measures, including
information from monitoring of the
Navy’s implementation of the mitigation
measures as prescribed under previous
IHAs for this and other projects in the
Hood Canal, we have preliminarily
determined that the proposed mitigation
measures provide the means of effecting
the least practicable impact on marine
mammal species or stocks and their
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habitat, paying particular attention to
rookeries, mating grounds, and areas of
similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an
activity, Section 101(a)(5)(D) of the
MMPA states that NMFS must set forth
‘‘requirements pertaining to the
monitoring and reporting of such
taking’’. The MMPA implementing
regulations at 50 CFR 216.104(a)(13)
indicate that requests for incidental take
authorizations must include the
suggested means of accomplishing the
necessary monitoring and reporting that
will result in increased knowledge of
the species and of the level of taking or
impacts on populations of marine
mammals that are expected to be
present in the proposed action area.
Any monitoring requirement we
prescribe should accomplish one or
more of the following general goals:
1. An increase in the probability of
detecting marine mammals, both within
defined zones of effect (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 stimuli that we
associate with specific adverse effects,
such as behavioral harassment or
hearing threshold shifts;
3. An increase in our understanding
of how marine mammals respond to
stimuli expected to result in incidental
take and how anticipated adverse effects
on individuals may impact the
population, stock, or species
(specifically through effects on annual
rates of recruitment or survival) through
any of the following methods:
• Behavioral observations in the
presence of stimuli compared to
observations in the absence of stimuli
(need to be able to accurately predict
pertinent information, e.g., received
level, distance from source);
• Physiological measurements in the
presence of stimuli compared to
observations in the absence of stimuli
(need to be able to accurately predict
pertinent information, e.g., received
level, distance from source);
• 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; or
5. An increase in our understanding
of the effectiveness of certain mitigation
and monitoring measures.
The Navy submitted a marine
mammal monitoring plan as part of the
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IHA application for year two of this
project. It will be applied to year three
of this project and can be found on the
Internet at www.nmfs.noaa.gov/pr/
permits/incidental.htm. The plan has
been successfully implemented by the
Navy under the previous IHA and may
be modified or supplemented based on
comments or new information received
from the public during the public
comment period.
Visual Marine Mammal Observations
The Navy will collect sighting data
and behavioral responses to
construction for marine mammal
species observed in the region of
activity during the period of activity. All
observers will be trained in marine
mammal identification and behaviors
and are required to have no other
construction-related tasks while
conducting monitoring. The Navy will
monitor the shutdown zone and
disturbance zone before, during, and
after pile driving, with observers located
at the best practicable vantage points.
Based on our requirements, the Marine
Mammal Monitoring Plan would
implement the following procedures for
pile driving:
• MMOs would be located at the best
vantage point(s) in order to properly see
the entire shutdown zone and as much
of the disturbance zone as possible.
• During all observation periods,
observers will use binoculars and the
naked eye to search continuously for
marine mammals.
• If the shutdown zones are obscured
by fog or poor lighting conditions, pile
driving at that location will not be
initiated until that zone is visible.
Should such conditions arise while
impact driving is underway, the activity
would be halted.
• The shutdown and disturbance
zones around the pile will be monitored
for the presence of marine mammals
before, during, and after any pile driving
or removal activity.
Individuals implementing the
monitoring protocol will assess its
effectiveness using an adaptive
approach. Monitoring biologists will use
their best professional judgment
throughout implementation and seek
improvements to these methods when
deemed appropriate. Any modifications
to protocol will be coordinated between
NMFS and the Navy.
Data Collection
We require that observers use
approved data forms. Among other
pieces of information, the Navy will
record detailed information about any
implementation of shutdowns,
including the distance of animals to the
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pile and description of specific actions
that ensued and resulting behavior of
the animal, if any. In addition, the Navy
will attempt to distinguish between the
number of individual animals taken and
the number of incidents of take. We
require that, at a minimum, the
following information be collected on
the sighting forms:
• Date and time that monitored
activity begins or ends;
• Construction activities occurring
during each observation period;
• Weather parameters (e.g., percent
cover, visibility);
• Water conditions (e.g., sea state,
tide state);
• Species, numbers, and, if possible,
sex and age class of marine mammals;
• Description of any observable
marine mammal behavior patterns,
including bearing and direction of travel
and distance from pile driving activity;
• Distance from pile driving activities
to marine mammals and distance from
the marine mammals to the observation
point;
• Locations of all marine mammal
observations; and
• Other human activity in the area.
Reporting
A draft report would be submitted
within ninety calendar days of the
completion of the in-water work
window. The report will include marine
mammal observations pre-activity,
during-activity, and post-activity during
pile driving days, and will also provide
descriptions of any problems
encountered in deploying sound
attenuating devices, any behavioral
responses to construction activities by
marine mammals and a complete
description of all mitigation shutdowns
and the results of those actions and an
extrapolated total take estimate based on
the number of marine mammals
observed during the course of
construction. A final report must be
submitted within thirty days following
resolution of comments on the draft
report.
Monitoring Results From Previously
Authorized Activities
The Navy complied with the
mitigation and monitoring required
under the previous authorizations for
this project. Marine mammal monitoring
occurred before, during, and after each
pile driving event. During the course of
these activities, the Navy did not exceed
the take levels authorized under the
IHAs.
In accordance with the 2012 IHA, the
Navy submitted a Year 1 Marine
Mammal Monitoring Report (2012–
2013), covering the period of July 16
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through February 15. Due to delays in
beginning the project the first day of
monitored pile driving activity occurred
on September 28, 2012, and a total of 78
days of pile driving occurred between
then and February 14, 2013. That total
included 56 days of vibratory driving
only, three days of only impact driving,
and 19 days where both vibratory and
impact driving occurred, with a
maximum concurrent deployment of
two vibratory drivers and one impact
driver.
Monitoring was conducted in two
areas: (1) Primary visual surveys within
the disturbance and shutdown zones in
the WRA (approximately 500-m radius),
(2) boat surveys outside the WRA but
within the disturbance zone. The latter
occurred only during acoustic
monitoring accomplished at the outset
of the work period, which required a
small vessel be deployed outside the
Table 3 summarizes monitoring
results from years one and two of the
EHW–2 project, including observations
from all monitoring effort (including
while pile driving was not actively
occurring) and records of unique
observations during active pile driving
(seen in the far right column). Primary
surveys refer to observations by
stationary and vessel-based monitors
within the WRA. Boat surveys refer to
vessel-based surveys conducted outside
the WRA (Year 1 only). No Steller sea
lions have been observed within defined
ZOIs during active pile driving, and no
killer whales have been observed during
any project monitoring at NBKB. For
more detail, including full monitoring
results and analysis, please see the
monitoring reports at
www.nmfs.noaa.gov/pr/permits/
incidental.htm.
WRA. Marine mammal observers were
placed on construction barges, the
construction pier, and vessels located in
near-field (within the WRA) and farfield (outside the WRA) locations, in
accordance with the Marine Mammal
Monitoring Plan.
Monitoring for the second year of
construction was conducted throughout
the 2013–14 work window (i.e., midJuly to mid-February). The monitoring
was conducted in the same manner as
the first year, but was limited to within
the WRA as no acoustic monitoring was
conducted during the second year. At
the time of this writing, the Navy has
provided a draft of the Year 2 Marine
Mammal Report and it is under review.
We have made the draft report available
for public review and comment prior to
any final decision regarding this
proposed authorization.
TABLE 3—SUMMARY MARINE MAMMAL MONITORING RESULTS, EHW–2 YEARS 1–2
Species
Primary surveys, Y1 .............
California sea lion .................
Harbor seal ...........................
California sea lion .................
Steller sea lion ......................
Harbor seal ...........................
Harbor porpoise ....................
California sea lion .................
Harbor seal ...........................
Boat surveys, Y1 ..................
Primary surveys, Y2 .............
Total number
individuals
observed
Total number
groups observed
Activity 1
30
939
21
3
73
10
77
3,046
Maximum group
size
30
984
126
3
76
57
83
3,229
Total individuals
observed
(active pile driving
and within disturbance zone only)
1
4
20
1
2
10
3
5
4
214
22
0
22
36
10
713
1 Total observation effort during active pile driving: Year 1—530 hours, 50 minutes on eighty construction days; Year 2—1,247 hours, 27 minutes on 162 construction days.
Acoustic Monitoring—During the first
year of construction for EHW–2, the
Navy conducted acoustic monitoring as
required under the IHA. During year
one, 24- to 36-in diameter piles were
primarily driven, by vibratory and
impact driving. Only one 48-in pile was
driven, so no data are provided for that
pile size. All piles were steel pipe piles.
Primary objectives for the acoustic
monitoring were to characterize
underwater and airborne source levels
for each pile size and hammer type and
to verify distances to relevant threshold
levels by characterizing site-specific
transmission loss. Measurements of
impact driving for 24-in piles showed a
high degree of variation (SD = 24.1)
because many of these piles were driven
either on land or in extremely shallow
water, while others were driven in
deeper water more characteristic of
typical driving conditions for EHW–2.
Select results are reproduced here
(Tables 4–5); the interested reader may
find the entire report posted at
www.nmfs.noaa.gov/pr/permits/
incidental.htm. Acoustic monitoring
was also conducted during the TPP and
during year one of the EHW–1 project.
Those reports may be found at the same
address. Acoustic measurements from
NBKB are discussed further below in
‘‘Estimated Take by Incidental
Harassment.’’
TABLE 4—ACOUSTIC MONITORING RESULTS FROM 2012–13 ACTIVITIES AT EHW–2 (YEAR 1)
Underwater
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Pile size
(in)
24
36
24
36
......................................
......................................
......................................
......................................
Hammer type 1
Airborne
n2
RL 3
Impact ...............................
Impact ...............................
Vibratory ...........................
Vibratory ...........................
41
26
71
113
SD 4
179
188
163
169
24.1
5.0
8.3
4.3
TL 5
18.6
14.9
15.3
16.8
RL 6
SD
103
102
95
103
1.0
2.2
3.7
3.2
1 All data for impact driving include use of bubble curtain; 2 n = sample size, or number of measured pile driving events; 3 Received level at 10
m, presented in dB rms; 4 Standard deviation; 5 Transmission loss (log10); 6 Received level at 15 m, presented in dB rms (Z-weighted Leq).
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given noise from wind and wave action,
in the far field (Table 5). Also, as
observed during previous monitoring
events at NBKB, measured levels in
shallower water at the far side of Hood
Canal are sometimes louder than
measurements made closer to the source
in the deeper open channel. These
events are unexplained. Estimated
For vibratory driving, measured
source levels were below the 180-dB
threshold. Calculation of average
distances to the 120-dB threshold was
complicated by variability in
propagation of sound at greater
distances, variability in measured
sounds from event to event, and the
difficulty of making measurements,
radial distances to the 120-dB threshold
were highly variable, but typically less
than the maximum distance as
constrained by land (i.e., 13,800 m;
Table 9). The topography of Hood Canal
realistically constrains distances to
7,000 m to the south of the project area.
TABLE 5—MEASURED VALUES FROM TPP AND EHW–2 ACOUSTIC MONITORING, INCLUDING DISTANCES TO RELEVANT
THRESHOLDS
Project
Source level
(dB rms)
Type
Measured distances to relevant thresholds
(rms)
Transmission
loss
120-dB 1
TPP ...........
TPP ...........
TPP ...........
EHW–2
(Y1).
EHW–2
(Y1).
Impact; 36-in ..............
Impact; 48-in ..............
Vibratory; 36- to 48-in
Impact; 36-in ..............
Vibratory; 36-in ..........
181 (avg)/183 (max) ..
187 (avg)/188 (max) ..
....................................
188 dB (avg)/191 dB
(max).
....................................
160-dB
180-dB
16.4
13.4
........................
14.9
n/a ..............................
n/a ..............................
1,200–8,000+ m .........
n/a ..............................
425 m ......
1,300 m ...
n/a ...........
670 m ......
35 m ........
60 m ........
n/a ...........
45 m ........
<10 m.
15 m.
n/a.
12 m.
........................
4,400 m (avg)/10,250
m (max).
n/a ...........
n/a ...........
n/a.
190-dB
1 Distances to 120-dB threshold are estimated from measured source level and transmission loss values. The distances themselves are not
measured.
Sound levels during soft starts were
typically lower than those levels at the
initiation and completion of continuous
vibratory driving. However, levels
during continuous driving varied
considerably and were at times lower
than those produced during the soft
starts. It is difficult to assign a level that
describes how much lower the soft start
sound levels were than continuous
levels. Similarly inconclusive results
were seen from monitoring associated
with the TPP.
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Estimated Take by Incidental
Harassment
Except with respect to certain
activities not pertinent here, section
3(18) of the MMPA defines
‘‘harassment’’ as any act of pursuit,
torment, or annoyance which has the
potential to injure a marine mammal or
marine mammal stock in the wild; or
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. The former is
termed Level A harassment and the
latter is termed Level B harassment.
All anticipated takes would be by
Level B harassment resulting from
vibratory and impact pile driving and
involving temporary changes in
behavior. The proposed mitigation and
monitoring measures are expected to
minimize the possibility of injurious or
lethal takes such that take by Level A
harassment, serious injury, or mortality
is considered discountable. However, it
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is unlikely that injurious or lethal takes
would occur even in the absence of the
planned mitigation and monitoring
measures.
If a marine mammal responds to a
stimulus by changing its behavior (e.g.,
through relatively minor changes in
locomotion direction/speed or
vocalization behavior), the response
may or may not constitute taking at the
individual level, and is unlikely to
affect the stock or the species as a
whole. However, if a sound source
displaces marine mammals from an
important feeding or breeding area for a
prolonged period, impacts on animals or
on the stock or species could potentially
be significant (e.g., Lusseau and Bejder,
2007; Weilgart, 2007). Given the many
uncertainties in predicting the quantity
and types of impacts of sound on
marine mammals, it is common practice
to estimate how many animals are likely
to be present within a particular
distance of a given activity, or exposed
to a particular level of sound.
This practice potentially
overestimates the numbers of marine
mammals taken. For example, during
the past fifteen years, killer whales have
been observed within the project area
twice. On the basis of that information,
an estimated amount of potential takes
for killer whales is presented here.
However, while a pod of killer whales
could potentially visit again during the
project timeframe, and thus be taken, it
is more likely that they will not.
Although incidental take of killer
whales and Dall’s porpoises was
authorized for 2011–12 and 2012–13
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activities at NBKB on the basis of past
observations of these species, no such
takes were recorded and no individuals
of these species were observed.
Similarly, estimated actual take levels
(observed takes extrapolated to the
remainder of unobserved but ensonified
area) were significantly less than
authorized levels of take for the
remaining species. In addition, it is
often difficult to distinguish between
the individuals harassed and incidences
of harassment. In particular, for
stationary activities, it is more likely
that some smaller number of individuals
may accrue a number of incidences of
harassment per individual than for each
incidence to accrue to a new individual,
especially if those individuals display
some degree of residency or site fidelity
and the impetus to use the site (e.g.,
because of foraging opportunities) is
stronger than the deterrence presented
by the harassing activity.
The project area is not believed to be
particularly important habitat for
marine mammals, nor is it considered
an area frequented by marine mammals,
although harbor seals are year-round
residents of Hood Canal and sea lions
are known to haul-out on submarines
and other man-made objects at the
NBKB waterfront (although typically at
a distance of a mile or greater from the
project site). Therefore, behavioral
disturbances that could result from
anthropogenic sound associated with
these activities are expected to affect
only a relatively small number of
individual marine mammals, although
those effects could be recurring over the
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life of the project if the same individuals
remain in the project vicinity.
The Navy has requested authorization
for the incidental taking of small
numbers of Steller sea lions, California
sea lions, harbor seals, transient killer
whales, and harbor porpoises in the
Hood Canal that may result from pile
driving during construction activities
associated with the wharf construction
project described previously in this
document. In order to estimate the
potential incidents of take that may
occur incidental to the specified
activity, we must first estimate the
extent of the sound field that may be
produced by the activity and then
consider in combination with
information about marine mammal
density or abundance in the project
area. We first provide information on
applicable sound thresholds for
determining effects to marine mammals
before describing the information used
in estimating the sound fields, the
available marine mammal density or
abundance information, and the method
of estimating potential incidences of
take.
Sound Thresholds
We use generic sound exposure
thresholds to determine when an
activity that produces sound might
result in impacts to a marine mammal
such that a take by harassment might
occur. To date, no studies have been
conducted that explicitly examine
impacts to marine mammals from pile
driving sounds or from which empirical
sound thresholds have been established.
These thresholds should be considered
guidelines for estimating when
harassment may occur (i.e., when an
animal is exposed to levels equal to or
exceeding the relevant criterion) in
specific contexts; however, useful
contextual information that may inform
our assessment of effects is typically
lacking and we consider these
thresholds as step functions. NMFS is
currently revising these acoustic
guidelines; for more information on that
process, please visit
www.nmfs.noaa.gov/pr/acoustics/
guidelines.htm. Vibratory pile driving
produces continuous noise and impact
pile driving produces impulsive noise.
TABLE 6—CURRENT ACOUSTIC EXPOSURE CRITERIA
Criterion
Definition
Threshold
Level A harassment (underwater) ......................
180 dB (cetaceans)/190 dB (pinnipeds) (rms).
Level B harassment (underwater) ......................
Injury (PTS—any level above that which is
known to cause TTS).
Behavioral disruption .......................................
Level B harassment (airborne)* .........................
Behavioral disruption .......................................
160 dB (impulsive source)/120 dB (continuous
source) (rms).
90 dB (harbor seals)/100 dB (other pinnipeds)
(unweighted).
* NMFS has not established any formal criteria for harassment resulting from exposure to airborne sound. However, these thresholds represent
the best available information regarding the effects of pinniped exposure to such sound and NMFS’ practice is to associate exposure at these
levels with Level B harassment.
Distance to Sound Thresholds
Underwater Sound Propagation
Formula—Pile driving generates
underwater noise that can potentially
result in disturbance to marine
mammals in the project area.
Transmission loss (TL) is the decrease
in acoustic intensity as an acoustic
pressure wave propagates out from a
source. TL parameters vary with
frequency, temperature, sea conditions,
current, source and receiver depth,
water depth, water chemistry, and
bottom composition and topography.
The general formula for underwater TL
is:
TL = B * log10(R1/R2),
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where
R1 = the distance of the modeled SPL from
the driven pile, and
R2 = the distance from the driven pile of the
initial measurement.
This formula neglects loss due to
scattering and absorption, which is
assumed to be zero here. The degree to
which underwater sound propagates
away from a sound source is dependent
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on a variety of factors, most notably the
water bathymetry and presence or
absence of reflective or absorptive
conditions including in-water structures
and sediments. Spherical spreading
occurs in a perfectly unobstructed (freefield) environment not limited by depth
or water surface, resulting in a 6 dB
reduction in sound level for each
doubling of distance from the source
(20*log[range]). Cylindrical spreading
occurs in an environment in which
sound propagation is bounded by the
water surface and sea bottom, resulting
in a reduction of 3 dB in sound level for
each doubling of distance from the
source (10*log[range]). A practical
spreading value of fifteen is often used
under conditions, such as Hood Canal,
where water increases with depth as the
receiver moves away from the shoreline,
resulting in an expected propagation
environment that would lie between
spherical and cylindrical spreading loss
conditions. Practical spreading loss (4.5
dB reduction in sound level for each
doubling of distance) is assumed here.
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Underwater Sound—The intensity of
pile driving sounds is greatly influenced
by factors such as the type of piles,
hammers, and the physical environment
in which the activity takes place. A
large quantity of literature regarding
SPLs recorded from pile driving projects
is available for consideration. In order to
determine reasonable SPLs and their
associated effects on marine mammals
that are likely to result from pile driving
at NBKB, studies with similar properties
to the specified activity were evaluated,
including measurements conducted for
driving of steel piles at NBKB as part of
the TPP (Illingworth & Rodkin, 2012).
During the TPP, SPLs from driving of
24-, 36-, and 48-in piles by impact and
vibratory hammers were measured.
Overall, studies which met the
following parameters were considered:
(1) Pile size and materials: Steel pipe
piles (30- to 72-in diameter); (2)
Hammer machinery: Vibratory and
impact hammer; and (3) Physical
environment: shallow depth (less than
30 m).
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TABLE 7—UNDERWATER SPLS FROM MONITORED CONSTRUCTION ACTIVITIES USING IMPACT HAMMERS
Project and location
Water depth
(m)
Pile size and type
Eagle Harbor Maintenance Facility, WA 1 ..........
Friday Harbor Ferry Terminal, WA 2 ..................
Humboldt Bay Bridges, CA 3 ..............................
Mukilteo Test Piles, WA 4 ...................................
Anacortes Ferry, WA 5 ........................................
Test Pile Program, NBKB 6 ................................
EHW–2, Year 1, NBKB 7 ....................................
Carderock Pier, NBKB 8 .....................................
Russian River, CA 3 ............................................
Test Pile Program, NBKB 6 ................................
California 3 ..........................................................
Richmond-San Rafael Bridge, CA 3 ...................
30-in
30-in
36-in
36-in
36-in
36-in
36-in
42-in
48-in
48-in
60-in
66-in
steel pipe ..................................................
steel pipe ..................................................
CISS pipe .................................................
steel pipe ..................................................
steel pipe ..................................................
steel pipe ..................................................
steel pipe ..................................................
steel pipe ..................................................
CISS pipe .................................................
steel pipe ..................................................
CISS pipe .................................................
cast-in-drilled-hole steel pipe ....................
10
10
10
7.3
12.8
13.7–26.8
13.7–26.8
14.6–21.3
2
26.2–28
10
4
Measured SPLs
192
196
193
195
199
196
194
195
195
194
195
195
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
(rms)
at
at
at
at
at
at
at
at
at
at
at
at
10
10
10
10
10
10
10
10
10
10
10
10
m.
m.
m.
m.
m.
m.
m.9
m.10
m.
m.
m.11
m.
Sources: 1 MacGillivray and Racca, 2005; 2 Laughlin, 2005; 3 Caltrans, 2012; 4 MacGillivray, 2007; 5 Sexton, 2007; 6 Illingworth & Rodkin, 2012;
& Rodkin, 2013; 8 DoN, 2009.
9 Bubble curtain in place for all measurements.
10 Source level at 10 m estimated based on measurements at distances of 48–387 m.
11 Specific location/project unknown. Summary value possibly comprising multiple events rather than a single event.
7 Illingworth
SPLs measured during pile installation
using a vibratory hammer. For impact
driving, a source value of 195 dB rms at
10 m was the average value reported
from the listed studies, and is consistent
with measurements from the TPP and
Carderock Pier pile driving projects at
NBKB, which had similar pile materials
(48- and 42-inch hollow steel piles,
respectively), water depth, and substrate
type as the EHW–2 project site. For
vibratory pile driving, the Navy selected
The tables presented here detail
representative pile driving SPLs that
have been recorded from similar
construction activities in recent years.
Due to the similarity of these actions
and the Navy’s proposed action, these
values represent reasonable SPLs which
could be anticipated, and which were
used in the acoustic modeling and
analysis. Table 7 displays SPLs
measured during pile installation using
an impact hammer and Table 8 displays
the most conservative value (72-in piles;
180 dB rms at 10 m) available when
initially assessing EHW–2 project
impacts, prior to the first year of the
project. Since then, data have become
available that indicate, on average, a
lower source level for vibratory pile
driving (e.g., 172 dB rms for 48-in steel
piles). However, for consistency we
have maintained the initial conservative
assumption regarding source level for
vibratory driving.
TABLE 8—UNDERWATER SPLS FROM MONITORED CONSTRUCTION ACTIVITIES USING VIBRATORY HAMMERS
Project and location
WA 1
Pile size and type
Vashon Terminal,
..................
Keystone Terminal, WA 2 ...............
Edmonds Ferry Terminal, WA 3 .....
Anacortes Ferry Terminal, WA 4 ....
California 5 ......................................
Test Pile Program, NBKB 6 ............
EHW–2, Year 1, NBKB 7 ................
Test Pile Program, NBKB 6 ............
California 3 ......................................
30-in
30-in
36-in
36-in
36-in
36-in
36-in
48-in
72-in
steel
steel
steel
steel
steel
steel
steel
steel
steel
pipe
pipe
pipe
pipe
pipe
pipe
pipe
pipe
pipe
Water depth
.............................
.............................
.............................
.............................
.............................
.............................
.............................
.............................
.............................
Measured SPLs
6 m ................................................
8 m ................................................
5.8 m .............................................
12.7 m ...........................................
5 m ................................................
13.7–26.8 m ..................................
Avg of mid- and deep-depth .........
13.7–26.8 m ..................................
5 m ................................................
165 dB (rms) at 11 m.
165 dB (rms) at 10 m.
162–163 dB (rms) at 10 m.
168–170 dB (rms) at 10 m.
170 dB/175 dB (rms) at 10 m.8
154–169 dB (rms) at 10 m.
169 dB (rms) at 10 m.
172 dB (rms) at 10 m.
170 dB/180 dB (rms) at 10 m.8
wreier-aviles on DSK5TPTVN1PROD with NOTICES2
Sources: 1 Laughlin, 2010a; 2 Laughlin, 2010b; 3 Loughlin, 2011; 4 Loughlin, 2012; 5 Caltrans, 2012; 6 Illingworth & Rodkin, 2012; 7 Illingworth &
Rodkin, 2013.
8 Specific location/project unknown. Summary value possibly comprising multiple events rather than a single event. Average and maximum values presented.
All calculated distances to and the
total area encompassed by the marine
mammal sound thresholds are provided
in Table 9. The Navy used source values
of 185 dB rms for impact driving (the
mean SPL of the values presented in
Table 7, less 10 dB of sound attenuation
from use of a bubble curtain) and 180
dB rms for vibratory driving (the worstcase value from Table 8). Under the
worst-case construction scenario, up to
three vibratory drivers would operate
simultaneously with one impact driver.
Although radial distance and area
associated with the zone ensonified to
160 dB (the behavioral harassment
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threshold for pulsed sounds, such as
those produced by impact driving) are
presented in Table 9, this zone would be
subsumed by the 120-dB zone produced
by vibratory driving. Thus, behavioral
harassment of marine mammals
associated with impact driving is not
considered further here. Since the 160dB threshold and the 120-dB threshold
both indicate behavioral harassment,
pile driving effects in the two zones are
equivalent. Although not considered as
a likely construction scenario, if only
the impact driver was operated on a
given day incidental take on that day
would likely be lower because the area
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ensonified to levels producing Level B
harassment would be smaller (although
actual take would be determined by the
numbers of marine mammals in the area
on that day). The use of multiple
vibratory rigs at the same time would
result in a small additive effect with
regard to produced SPLs; however,
because the sound field produced by
vibratory driving would be truncated by
land in the Hood Canal, no increase in
actual sound field produced would
occur. There would be no overlap in the
190/180-dB sound fields produced by
rigs operating simultaneously.
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TABLE 9—CALCULATED DISTANCE(S) TO AND AREA ENCOMPASSED BY UNDERWATER MARINE MAMMAL SOUND
THRESHOLDS DURING PILE INSTALLATION
Distance 1
(m)
Threshold
Impact driving, pinniped injury (190 dB) ..................................................................................................................
Impact driving, cetacean injury (180 dB) .................................................................................................................
Impact driving, disturbance (160 dB)2 .....................................................................................................................
Vibratory driving, pinniped injury (190 dB) ..............................................................................................................
Vibratory driving, cetacean injury (180 dB) .............................................................................................................
Vibratory driving, disturbance (120 dB)3 .................................................................................................................
4.9.
22.
724.
2.1.
10.
13,800.
Area
(km2)
0.0001
0.002
1.65
< 0.0001
0.0003
41.4
1 SPLs
used for calculations were: 185 dB for impact and 180 dB for vibratory driving.
of 160-dB zone presented for reference. Estimated incidental take calculated on basis of larger 120-dB zone.
3 Hood Canal average width at site is 2.4 km, and is fetch limited from N to S at 20.3 km. Calculated range (over 222 km) is greater than actual sound propagation through Hood Canal due to intervening land masses. The greatest line-of-sight distance from pile driving locations
unimpeded by land masses is 13.8 km (i.e., the maximum possible distance for propagation of sound).
2 Area
Hood Canal does not represent open
water, or free field, conditions.
Therefore, sounds would attenuate as
they encounter land masses or bends in
the canal. As a result, the calculated
distance and areas of impact for the 120dB threshold cannot actually be attained
at the project area. See Figure 6–1 of the
Navy’s application for a depiction of the
size of areas in which each underwater
sound threshold is predicted to occur at
the project area due to pile driving.
Airborne Sound—Pile driving can
generate airborne sound that could
potentially result in disturbance to
marine mammals (specifically,
pinnipeds) which are hauled out or at
the water’s surface. As a result, the Navy
analyzed the potential for pinnipeds
hauled out or swimming at the surface
near NBKB to be exposed to airborne
SPLs that could result in Level B
behavioral harassment. A spherical
spreading loss model (i.e., 6 dB
reduction in sound level for each
doubling of distance from the source), in
which there is a perfectly unobstructed
(free-field) environment not limited by
depth or water surface, is appropriate
for use with airborne sound and was
used to estimate the distance to the
airborne thresholds.
As was discussed for underwater
sound from pile driving, the intensity of
pile driving sounds is greatly influenced
by factors such as the type of piles,
hammers, and the physical environment
in which the activity takes place. In
order to determine reasonable airborne
SPLs and their associated effects on
marine mammals that are likely to result
from pile driving at NBKB, studies with
similar properties to the proposed
action, as described previously, were
evaluated. Table 10 details
representative pile driving activities that
have occurred in recent years. Due to
the similarity of these actions and the
Navy’s proposed action, they represent
reasonable SPLs which could be
anticipated. Measured values from the
TPP and EHW–2 (Year 1) are generally
lower than those assumed for Navy’s
initial analysis for impact driving and
generally equivalent to what was
assumed for vibratory driving (see
values for Northstar Island and
Keystone Ferry Terminal in Table 10;
note that these equate to approximately
118 dB and 96 dB when standardized to
15 m). However, these values were
retained for impact assessment because
they either result in a more conservative
distance to threshold (impact driving) or
are equivalent (vibratory driving). Please
see Illingworth & Rodkin (2012, 2013)
for details of the TPP and EHW–2
measurements.
TABLE 10—AIRBORNE SPLS FROM SIMILAR CONSTRUCTION ACTIVITIES
Project and location
Pile size and type
Northstar Island, AK 1 .....................
TPP, NBKB 2 ..................................
TPP, NBKB 2 ..................................
EHW–2, Year 1, NBKB 3 ................
EHW–2, Year 1, NBKB 3 ................
EHW–2, Year 1, NBKB 3 ................
Keystone Ferry Terminal, WA 4 ......
TPP, NBKB 2 ..................................
EHW–2, Year 1, NBKB 3 ................
TPP, NBKB 2 ..................................
42-in
36-in
48-in
24-in
36-in
24-in
30-in
36-in
36-in
48-in
steel
steel
steel
steel
steel
steel
steel
steel
steel
steel
pipe
pipe
pipe
pipe
pipe
pipe
pipe
pipe
pipe
pipe
Measured SPLs 5
Method
.............................
.............................
.............................
.............................
.............................
.............................
.............................
.............................
.............................
.............................
Impact ...........................................
Impact ...........................................
Impact ...........................................
Impact ...........................................
Impact ...........................................
Vibratory ........................................
Vibratory ........................................
Vibratory ........................................
Vibratory ........................................
Vibratory ........................................
97 dB rms at 160 m.
109 dB Lmax at 15 m.
107 dB at 15 m.
111 dB Lmax at 15 m.
111 dB at 15 m.
95 dB Leq at 15 m.
98 dB rms at 11 m.
93 dB Leq at 15 m.
103 Leq dB at 15 m.
94 dB Leq at 15 m.
wreier-aviles on DSK5TPTVN1PROD with NOTICES2
Sources: 1 Blackwell et al., 2004; 2 Illingworth & Rodkin, 2012; 3 Illingworth & Rodkin, 2013; 4 Laughlin, 2010b.
5 Lmax = maximum level; Leq = equivalent level.
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Based on these values and the
assumption of spherical spreading loss,
distances to relevant thresholds and
associated areas of ensonification under
the multi-rig scenario (i.e., combined
impact and vibratory driving) are
presented in Table 11. See Figure 6–2 of
the Navy’s application for a depiction of
the size of areas in which each airborne
sound threshold is predicted to occur at
the project area due to pile driving.
TABLE 11—DISTANCES TO RELEVANT
SOUND THRESHOLDS AND AREAS OF
ENSONIFICATION, AIRBORNE SOUND
Group
wreier-aviles on DSK5TPTVN1PROD with NOTICES2
Harbor
seals ......
Sea lions ...
Threshold
(dB)
Distance to
threshold (m) and
associated area of
ensonification
(km2); combined
rig scenario
(worst-case)
90 dB
100 dB
361, 0.07
114, 0.005
Marine Mammal Densities
The Navy has developed, with input
from regional marine mammal experts,
estimates of marine mammal densities
in Washington inland waters for the
Navy Marine Species Density Database
(NMSDD). A technical report (Hanser et
al., 2014) describes methodologies and
available information used to derive
these densities, which are generally
considered the best available
information for Washington inland
waters, except where specific local
abundance information is available.
Initial impact assessment for the EHW–
2 project relied on data available at the
time the application was submitted,
including survey efforts conducted in
the project area. Here, we rely on
NMSDD density information for the
harbor seal, killer whale, and harbor
porpoise and use local abundance data
for the California sea lion and Steller sea
lion. This approach is the same as that
taken for estimating take for Year 2 of
the EHW–2 project, which represented a
departure from the approach taken for
Year 1 of EHW–2 for certain species.
Please see Appendix A of the Navy’s
application for more information on the
NMSDD information.
For all species, the most appropriate
information available was used to
estimate the number of potential
incidences of take. For harbor seals, this
involved published literature describing
harbor seal research conducted in
Washington and Oregon, including
counts from Hood Canal (Huber et al.,
2001; Jeffries et al., 2003). Killer whales
are known from two periods of
occurrence (2003 and 2005) and are not
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known to preferentially use any specific
portion of the Hood Canal. Therefore,
density was calculated as the maximum
number of individuals expected to be
present at a given time (Houghton et al.,
in prep.), divided by the area of Hood
Canal. The best information available
for the remaining species in Hood Canal
came from surveys conducted by the
Navy at the NBKB waterfront or in the
vicinity of the project area.
Beginning in April 2008, Navy
personnel have recorded sightings of
marine mammals occurring at known
haul-outs along the NBKB waterfront,
including docked submarines or other
structures associated with NBKB docks
and piers and the nearshore pontoons of
the floating security fence. Sightings of
marine mammals within the waters
adjoining these locations were also
recorded. Sightings were attempted
whenever possible during a typical
work week (i.e., Monday through
Friday), but inclement weather,
holidays, or security constraints often
precluded surveys. These sightings took
place frequently, although without a
formal survey protocol. During the
surveys, staff visited each of the abovementioned locations and recorded
observations of marine mammals.
Surveys were conducted using
binoculars and the naked eye from
shoreline locations or the piers/wharves
themselves. Because these surveys
consist of opportunistic sighting data
from shore-based observers, largely of
hauled-out animals, there is no
associated survey area appropriate for
use in calculating a density from the
abundance data. Data were compiled for
the period from April 2008 through
December 2013 for analysis here, and
these data provide the basis for take
estimation for Steller and California sea
lions. Other information, including
sightings data from other Navy survey
efforts at NBKB, is available for these
two species, but these data provide the
most conservative (i.e., highest) local
abundance estimates (and thus the
highest estimates of potential take).
These data are also most appropriate for
these two species because they are
attracted to the NBKB waterfront due to
the availability of suitable haul-out
sites. The cetaceans and (to a lesser
extent) the harbor seal are not
specifically attracted to any attribute of
the project area and are assumed to
occur uniformly throughout the project
area.
In addition, vessel-based marine
wildlife surveys were conducted
according to established survey
protocols during July through
September 2008 and November through
May 2009–10 (Tannenbaum et al., 2009,
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2011). Eighteen complete surveys of the
nearshore area resulted in observations
of four marine mammal species (harbor
seal, California sea lion, harbor
porpoise, and Dall’s porpoise). These
surveys operated along pre-determined
transects parallel to the shoreline from
the nearshore out to approximately
550 m from shoreline, at a spacing of
100 yd, and covered the entire NBKB
waterfront (approximately 3.9 km2 per
survey) at a speed of 5 kn or less. Two
observers recorded sightings of marine
mammals both in the water and hauled
out, including date, time, species,
number of individuals, age (juvenile,
adult), behavior (swimming, diving,
hauled out, avoidance dive), and haulout location. Positions of marine
mammals were obtained by recording
distance and bearing to the animal with
a rangefinder and compass, noting the
concurrent location of the boat with
GPS, and, subsequently, analyzing these
data to produce coordinates of the
locations of all animals detected. These
surveys resulted in the only observation
of a Dall’s porpoise near NBKB, but
these surveys do not afford any
information used in take estimation
here.
The Navy also conducted vessel-based
line transect surveys in Hood Canal on
non-construction days during the 2011
TPP in order to collect additional data
for species present in Hood Canal.
These surveys detected three marine
mammal species (harbor seal, California
sea lion, and harbor porpoise), and
included surveys conducted in both the
main body of Hood Canal, near the
project area, and baseline surveys
conducted for comparison in Dabob
Bay, an area of Hood Canal that is not
affected by sound from Navy actions at
the NBKB waterfront. The surveys
operated along pre-determined transects
that followed a double saw-tooth pattern
to achieve uniform coverage of the
entire NBKB waterfront. The vessel
traveled at a speed of approximately 5
kn when transiting along the transect
lines. Two observers recorded sightings
of marine mammals both in the water
and hauled out, including the date,
time, species, number of individuals,
and behavior (swimming, diving, etc.).
Positions of marine mammals were
obtained by recording the distance and
bearing to the animal(s), noting the
concurrent location of the boat with
GPS, and subsequently analyzing these
data to produce coordinates of the
locations of all animals detected.
Sighting information for harbor
porpoises was corrected for detectability
(g(0) = 0.54; Barlow, 1988; Calambokidis
et al., 1993; Carretta et al., 2001).
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wreier-aviles on DSK5TPTVN1PROD with NOTICES2
Distance sampling methodologies were
used to estimate densities of animals for
the data. This information provides the
best information for harbor porpoises.
The cetaceans, as well as the harbor
seal, appear to range throughout Hood
Canal; therefore, this analysis assumes
that harbor seal, transient killer whale,
and harbor porpoise are uniformly
distributed in the project area. However,
it should be noted that there have been
no observations of cetaceans within the
floating security barriers at NBKB; these
barriers thus appear to effectively
prevent cetaceans from approaching the
shutdown zones. Although the Navy
will implement a precautionary
shutdown zone for cetaceans, anecdotal
evidence suggests that cetaceans are not
at risk of Level A harassment at NBKB
even from louder activities (e.g., impact
pile driving). The remaining species that
occur in the project area, Steller sea lion
and California sea lion, do not appear to
utilize most of Hood Canal. The sea
lions appear to be attracted to the manmade haul-out opportunities along the
NBKB waterfront while dispersing for
foraging opportunities elsewhere in
Hood Canal. California sea lions were
not reported during aerial surveys of
Hood Canal (Jeffries et al., 2000), and
Steller sea lions have been documented
almost solely at the NBKB waterfront.
Description of Take Calculation
The take calculations presented here
rely on the best data currently available
for marine mammal populations in the
Hood Canal. The formula was
developed for calculating take due to
pile driving activity and applied to each
group-specific sound impact threshold.
The formula is founded on the following
assumptions:
• All marine mammal individuals
potentially available are assumed to be
present within the relevant area, and
thus incidentally taken;
• An individual can only be taken
once during a 24-h period;
• There were will be 195 total days of
activity and the largest ZOI equals 41.4
km2;
• Exposure modeling assumes that
one impact pile driver and three
vibratory pile drivers are operating
concurrently; and,
• Exposures to sound levels above the
relevant thresholds equate to take, as
defined by the MMPA.
The calculation for marine mammal
takes is estimated by:
Exposure estimate = (n * ZOI) * days of
total activity
Where:
n = density estimate used for each species/
season
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ZOI = sound threshold ZOI area; the area
encompassed by all locations where the
SPLs equal or exceed the threshold being
evaluated
n * ZOI produces an estimate of the
abundance of animals that could be
present in the area for exposure, and is
rounded to the nearest whole number
before multiplying by days of total
activity.
The ZOI impact area is the estimated
range of impact to the sound criteria.
The relevant distances specified in
Table 9 were used to calculate ZOIs
around each pile. The ZOI impact area
took into consideration the possible
affected area of the Hood Canal from the
pile driving site furthest from shore
with attenuation due to land shadowing
from bends in the canal. Because of the
close proximity of some of the piles to
the shore, the narrowness of the canal
at the project area, and the maximum
fetch, the ZOIs for each threshold are
not necessarily spherical and may be
truncated.
While pile driving can occur any day
throughout the in-water work window,
and the analysis is conducted on a per
day basis, only a fraction of that time
(typically a matter of hours on any given
day) is actually spent pile driving.
Acoustic monitoring conducted as part
of the TPP and year one of EHW–2
demonstrated that Level B harassment
zones for vibratory pile driving are
likely to be smaller than the zones
estimated through modeling based on
measured source levels and practical
spreading loss. Also of note is the fact
that the effectiveness of mitigation
measures in reducing takes is typically
not quantified in the take estimation
process. In addition, equating exposure
with response (i.e., a behavioral
response meeting the definition of take
under the MMPA) is a simplistic and
conservative assumption. For these
reasons, these take estimates are likely
to be conservative. See Table 14 for total
estimated incidents of take.
Airborne Sound—No incidences of
incidental take resulting solely from
airborne sound are likely, as distances
to the harassment thresholds would not
reach areas where pinnipeds may haul
out. Harbor seals can haul out at a
variety of natural or manmade locations,
but the closest known harbor seal haulout is at the Dosewallips River mouth
(London, 2006) and Navy waterfront
surveys and boat surveys have found it
rare for harbor seals to haul out along
the NBKB waterfront (Agness and
Tannenbaum, 2009; Tannenbaum et al.,
2009, 2011; DoN, 2013). Individual seals
have occasionally been observed hauled
out on pontoons of the floating security
fence within the restricted areas of
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32851
NBKB, but this area is not within the
airborne disturbance ZOI. Nearby piers
are elevated well above the surface of
the water and are inaccessible to
pinnipeds, and seals have not been
observed hauled out on the adjacent
shoreline. Sea lions typically haul out
on submarines docked at Delta Pier,
approximately one mile from the project
site.
We recognize that pinnipeds in the
water could be exposed to airborne
sound that may result in behavioral
harassment when looking with heads
above water. However, these animals
would previously have been ‘taken’ as a
result of exposure to underwater sound
above the behavioral harassment
thresholds, which are in all cases larger
than those associated with airborne
sound. Thus, the behavioral harassment
of these animals is already accounted
for in these estimates of potential take.
Multiple incidents of exposure to sound
above NMFS’ thresholds for behavioral
harassment are not believed to result in
increased behavioral disturbance, in
either nature or intensity of disturbance
reaction. Therefore, we do not believe
that authorization of incidental take
resulting from airborne sound for
pinnipeds is warranted, and airborne
sound is not discussed further here.
California Sea Lion—California sea
lions occur regularly in the vicinity of
the project site, with the exception of
approximately mid-June through midAugust, as determined by Navy
waterfront surveys conducted from
April 2008 through December 2013
(Table 12). With regard to the range of
this species in Hood Canal and the
project area, we assume on the basis of
waterfront observations (Agness and
Tannenbaum, 2009; Tannenbaum et al.,
2009, 2011; HDR 2012a, 2012b; Hart
Crowser, 2013) that the opportunity to
haul out on submarines docked at Delta
Pier is a primary attractant for California
sea lions in Hood Canal, as they are not
typically observed elsewhere in Hood
Canal. Abundance is calculated as the
monthly average of the maximum
number observed in a given month, as
opposed to the overall average (Table
12). That is, the maximum number of
animals observed on any one day in a
given month was averaged for 2008–13,
providing a monthly average of the
maximum daily number observed. The
largest monthly average (71 animals)
was recorded in November, as was the
largest single daily count (122 animals).
The first California sea lion was
observed at NBKB in August 2009, and
their occurrence has been increasing
since that time (DoN, 2013).
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TABLE 12—CALIFORNIA SEA LION SIGHTING INFORMATION FROM NBKB, APRIL 2008–DECEMBER 2013
Number of
surveys with
animals
present
Number of
surveys
Month
Frequency of
presence 2
Abundance 3
January ........................................................................................................
February .......................................................................................................
March ...........................................................................................................
April ..............................................................................................................
May ..............................................................................................................
June .............................................................................................................
July ...............................................................................................................
August ..........................................................................................................
September ...................................................................................................
October ........................................................................................................
November ....................................................................................................
December ....................................................................................................
47
51
47
69
73
73
67
67
58
69
65
54
36
44
45
57
58
17
1
12
34
65
65
44
0.77
0.86
0.96
0.83
0.79
0.23
0.01
0.18
0.59
0.94
1
0.81
31.0
39.2
53.3
43.2
24.5
7.4
0.5
2.2
22.8
57.8
70.5
49.6
Total or average (in-water work season only) 1 ...................................
478
301
0.63
33.9
1 Totals
(number of surveys) and averages (frequency and abundance) presented for in-water work season (July–February) only. Information
from March–June presented for reference.
2 Frequency is the number of surveys with California sea lions present/number of surveys conducted.
3 Abundance is calculated as the monthly average of the maximum daily number observed in a given month.
California sea lion density for Hood
Canal was calculated to be 0.28 animals/
km2 for purposes of the NMSDD (Hanser
et al., 2014). Jeffries et al. (2003) split
the Washington inland waters area into
five regions, including Hood Canal as a
discrete region. To determine density,
the number of California sea lions
known to use haul-outs in the Hood
Canal was identified and then divided
by the area of the Hood Canal to give a
total density estimate. However, this
density was derived by averaging data
collected year-round. This project will
occur during the designated in-water
work window, so it is more appropriate
to use data collected at the NBKB
waterfront during those months (July–
February). The average of the monthly
averages for maximum daily numbers
observed (in a given month, during the
in-water work window) is 33.9 animals
(see Table 12). Exposures were
calculated assuming 34 individuals
could be present, and therefore exposed
to sound exceeding the behavioral
harassment threshold, on each day of
pile driving. This methodology is
conservative in that it assumes that all
individuals present potentially would
be taken on any given day of activity.
Steller Sea Lion
Steller sea lions were first
documented at the NBKB waterfront in
November 2008, while hauled out on
submarines at Delta Pier, and have been
periodically observed from October to
April since that time, as determined by
Navy waterfront surveys conducted
from April 2008 through December 2013
(Table 13). Steller sea lions are
occasionally observed in early May or
late September, but have never been
observed from approximately mid-May
through mid-September. We assume, on
the basis of waterfront observations
(Agness and Tannenbaum, 2009;
Tannenbaum et al., 2009, 2011; HDR
2012a, 2012b; Hart Crowser, 2013), that
Steller sea lions use available haul-outs
and foraging habitat similarly to
California sea lions. On occasions when
Steller sea lions are observed, they
typically occur in mixed groups with
California sea lions also present,
allowing observers to confirm their
identifications based on discrepancies
in size and other physical
characteristics. (DoN, 2013)
TABLE 13—STELLER SEA LION SIGHTING INFORMATION FROM NBKB, APRIL 2008–DECEMBER 2013
Number of
surveys
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Month
Number of
surveys with
animals
present
Frequency of
presence 2
Abundance 3
January ..........................................................................................................
February .........................................................................................................
March .............................................................................................................
April ................................................................................................................
May ................................................................................................................
June ...............................................................................................................
July .................................................................................................................
August ............................................................................................................
September .....................................................................................................
October ..........................................................................................................
November ......................................................................................................
December ......................................................................................................
47
51
47
69
73
73
67
67
58
69
65
54
12
7
12
21
6
0
0
0
2
30
37
18
0.26
0.14
0.26
0.30
0.08
0
0
0
0.03
0.43
0.57
0.33
1.5
1.4
1.8
2.3
1.5
0
0
0
0.8
3.7
5.7
2.6
Total or average (in-water work season only) 1 .....................................
478
106
0.22
2.0
1 Totals
(number of surveys) and averages (frequency and abundance) presented for in-water work season (July–February) only. Information
from March–June presented for reference.
2 Frequency is the number of surveys with Steller sea lions present/number of surveys conducted.
3 Abundance is calculated as the monthly average of the maximum daily number observed in a given month.
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Abundance is calculated in the same
manner described for California sea
lions (Table 13). That is, the maximum
number of animals observed on any one
day in a given month was averaged for
2008–13, providing a monthly average
of the maximum daily number observed.
The largest monthly average (six
animals) was recorded in November, as
was the largest single daily count
(eleven animals). NMSDD density for
Steller sea lions was also calculated in
a similar manner as that for California
sea lions (0.03 animals/km2; Hanser et
al., 2014) and, as for California sea lions,
local abundance data specific to the inwater work window is the most
appropriate information for use in
estimating take. The average of the
monthly averages for maximum daily
numbers observed (in a given month,
during the in-water work window) is
two animals (see Table 13). However, in
recognition that numbers of Steller sea
lions have been increasing every year
and reflecting a more typical group size
when Steller sea lions have been
observed, the Navy has requested a
precautionary assumption that three
individuals could be present, and
therefore exposed to sound exceeding
the behavioral harassment threshold, on
each day of pile driving.
Harbor Seal—The harbor seal density
used here is the same as that in the
NMSDD (Hanser et al., 2014). Jeffries et
al. (2003) conducted aerial surveys of
harbor seals in 1999 for the Washington
Department of Fish and Wildlife,
dividing the survey areas into seven
strata (including five in inland waters
and two in coastal waters). Survey effort
in the Hood Canal stratum yielded a
count of 711 harbor seals hauled out. To
account for animals in the water and not
observed during survey counts, a
correction factor of 1.53 was applied
(Huber et al., 2001) to derive a total
Hood Canal population of 1,088 seals.
The correction factor (1.53) was based
on the proportion of time seals spend on
land versus in the water over the course
of a day, and was derived by dividing
one by the percentage of time harbor
seals spent on land. These data came
from tags (VHF transmitters) applied to
harbor seals at six areas (Grays Harbor,
Tillamook Bay, Umpqua River, Gertrude
Island, Protection/Smith Islands, and
Boundary Bay, BC) within two different
harbor seal stocks (the coastal stock and
the Washington inland waters stock)
over four survey years. Although the
sampling areas included both coastal
and inland waters, with pooled
correction factors of 1.50 and 1.57,
respectively, Huber et al. (2001) found
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no significant difference in the
proportion of seals ashore among the six
sites and no interannual variation at one
site studied across years. Therefore, we
retain the total pooled correction factor
of 1.53 here. The Hood Canal
population is part of the inland waters
stock, and while not specifically
sampled, Jeffries et al. (2003) found the
VHF data to be broadly applicable to the
entire Washington harbor seal
population. Using this information and
the area of the Hood Canal stratum
yields a density estimate of 3.04
animals/km2.
However, to determine an
instantaneous in-water density estimate,
a secondary correction must be applied
to account for harbor seals that are
hauled out at any given moment. The
tagging research in 1991 and 1992
conducted by Huber et al. (2001) was
repeated for two sites by Jeffries et al.
(2003), using the same methods for the
1999 and 2000 survey years. These
surveys indicated that approximately 35
percent of harbor seals are in the water
versus hauled out on a daily basis
(Huber et al., 2001; Jeffries et al., 2003).
A corrected density was derived from
the number of harbor seals that are
present in the water at any one time (35
percent of 1,088, or approximately 381
individuals), divided by the area of the
Hood Canal, yielding an estimate of 1.06
animals/km2.
We recognize that over the course of
the day, while the proportion of animals
in the water may not vary significantly,
different individuals may enter and exit
the water (i.e., it is probable that greater
than 35 percent of seals will enter the
water at some point during the day).
Therefore, an instantaneous estimate of
animals in the water at a given time may
not produce an accurate assessment of
the number of individuals that enter the
water over the daily duration of the
activity. However, no data exist
regarding fine-scale harbor seal
movements within the project area on
time durations of less than a day, thus
precluding an assessment of ingress or
egress of different animals through the
action area. As such, it is impossible,
given available data, to determine
exactly what number of individuals
above 35 percent may potentially be
exposed to underwater sound.
Therefore, we are left to make a
decision, on the basis of limited
available information, regarding which
of these two scenarios (i.e., 100 percent
versus 35 percent of harbor seals are in
the water and exposed to sound)
produces a more accurate estimate of
the potential incidents of take.
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First, we understand that hauled-out
harbor seals are necessarily at haul-outs.
No significant harbor seal haul-outs are
located within or near the action area.
Harbor seals observed in the vicinity of
the NBKB shoreline are rarely hauledout (for example, in formal surveys
during 2007–08, approximately 86
percent of observed seals were
swimming), and when hauled-out, they
do so opportunistically (i.e., on floating
booms rather than established haulouts). Harbor seals are typically
unsuited for using manmade haul-outs
at NBKB, which are used by the larger
sea lions. Primary harbor seal haul-outs
in Hood Canal are generally located at
significant distance (20 km or more)
from the action area in Dabob Bay or
further south (see Figure 4–1 in the
Navy’s application), meaning that
animals casually entering the water
from haul-outs or flushing due to some
disturbance at those locations would not
be exposed to underwater sound from
the project; rather, only those animals
embarking on foraging trips and
entering the action area may be exposed.
Second, we know that harbor seals in
Hood Canal are not likely to have a
uniform distribution as is assumed
through use of a density estimate, but
are likely to be relatively concentrated
near areas of interest such as the haulouts found in Dabob Bay or foraging
areas. The majority of the action area
consists of the Level B harassment zone
in deeper waters of Hood Canal; past
observations from surveys and required
monitoring have confirmed that harbor
seals are less abundant in these waters.
Third, a typical pile driving day (in
terms of the actual time spent driving)
is somewhat shorter than may be
assumed (i.e., 8–15 hours) as a
representative pile driving day based on
daylight hours. Construction scheduling
and notional production rates in concert
with typical delays mean that hammers
are active for only some fraction of time
on pile driving ‘‘days’’. During the first
two years of construction for EHW–2,
pile driving occurred over
approximately 1,778 hours on 242 days,
for an approximate average of seven
hours per pile driving day.
What we know tells us that (1) the
turnover of harbor seals (in and out of
the water) is occurring primarily outside
the action area and would not be
expected to result in a greater number
of individuals entering the action area
within a given day and being harassed
than is assumed; (2) there are likely to
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be significantly fewer harbor seals in the
majority of the action area than would
be indicated by the uncorrected density;
and (3) pile driving actually occurs over
a limited timeframe on any given day
(i.e., less total time per day than would
be assumed based on daylight hours and
non-continuously), reducing the amount
of time over which new individuals
might enter the action area within a
given day. These factors lead us to
believe that the corrected density is
likely to more closely approximate the
number of seals that may be found in
the action area than does the
uncorrected density, and there are no
existing data that would indicate that
the proportion of individuals entering
the water within the predicted area of
effect during pile driving would be
dramatically larger than 35 percent.
Therefore, using 100 percent of the
population to estimate density would
likely result in a gross exaggeration of
potential take. Moreover, because the
Navy is typically unable to determine
from field observations whether the
same or different individuals are being
exposed, each observation is recorded as
a new take, although an individual
theoretically would only be considered
as taken once in a given day.
Finally, we note that during the
course of four previous IHAs over two
years (2011–12), the Navy was
authorized for 6,725 incidents of
incidental harassment (corrected for
actual number of pile driving days). The
total estimate of actual incidents of take
(observed takes and observations
extrapolated to unobserved area) was
868. This is almost certainly negatively
biased, but the huge disparity does
provide confirmation that we are not
significantly underestimating takes.
Killer Whales—Transient killer
whales are uncommon visitors to Hood
Canal, and may be present anytime
during the year. Transient pods (six to
eleven individuals per event) were
observed in Hood Canal for lengthy
periods of time (59–172 days) in 2003
(January–March) and 2005 (February–
June), feeding on harbor seals (London,
2006). These whales used the entire
expanse of Hood Canal for feeding. The
NMSDD used monthly unique sightings
data collected over the period 2004–
2010 and an average group size of 5.16
(Houghton et al., in prep.) to calculate
densities on a seasonal basis for each of
five geographic strata (Hanser et al.,
2014). Densities for the Hood Canal
stratum range from 0–0.0006 animals/
km2 across all seasons, which would
result in a prediction that zero animals
would be harassed by the project
activities.
However, while transient killer
whales are rare in the Hood Canal, it is
possible that a pod of animals could be
present. In the event that this occurred
in a similar manner to prior occurrences
(e.g., 59–172 days) and incidental take
were not authorized appropriately, there
could be significant project delays. In
estimating potential incidences of take
here, we make three assumptions: (1)
Transient killer whales have a
reasonable likelihood of occurrence in
the project area; (2) if whales were
present, they would occur in a pod of
six animals (the minimum pod size seen
in the 2003/2005 events but equivalent
to the average pod size reported by
Houghton et al. [in prep.]); and (3) the
pod would be present for thirty days.
This last assumption represents only
half of the minimum time killer whales
were present during the 2003/2005
events; however, we believe that it is
unlikely the whales would remain in
the area for a longer period in the
presence of a harassing stimulus (i.e.,
pile driving). In the absence of any
overriding contextual element (e.g.,
NBKB is not important as a breeding
area, and provides no unusual
concentration of prey), it is reasonable
to assume that whales would leave the
area if exposed to potentially harassing
levels of sound on each day that they
were present. In summary, we assume
here that, if killer whales occurred in
the project area, a pod of six whales
would be present—and could
potentially be harassed—for thirty days.
Harbor Porpoise—During vessel-based
line transect surveys on nonconstruction days during the TPP,
harbor porpoises were frequently
sighted within several kilometers of the
base, mostly to the north or south of the
project area, but occasionally directly
across from the NBKB waterfront on the
far side of Toandos Peninsula. Harbor
porpoise presence in the immediate
vicinity of the base (i.e., within one
kilometer) remained low. These data
were used to generate a density for
Hood Canal. Based on guidance from
other line transect surveys conducted
for harbor porpoises using similar
monitoring parameters (e.g., boat speed,
number of observers) (Barlow, 1988;
Calambokidis et al., 1993; Carretta et al.,
2001), the Navy determined the effective
strip width for the surveys to be one
kilometer, or a perpendicular distance
of 500 m from the transect to the left or
right of the vessel. The effective strip
width was set at the distance at which
the detection probability for harbor
porpoises was equivalent to one, which
assumes that all individuals on a
transect are detected. Only sightings
occurring within the effective strip
width were used in the density
calculation. By multiplying the trackline
length of the surveys by the effective
strip width, the total area surveyed
during the surveys was 471.2 km2.
Thirty-eight individual harbor porpoises
were sighted within this area, resulting
in a density of 0.0806 animals/km2. To
account for availability bias, or the
animals which are unavailable to be
detected because they are submerged,
the Navy utilized a g(0) value of 0.54,
derived from other similar line transect
surveys (Barlow, 1988; Calambokidis et
al., 1993; Carretta et al., 2001). This
resulted in a corrected density of 0.149
animals/km2.
TABLE 14—NUMBER OF POTENTIAL INCIDENTAL TAKES OF MARINE MAMMALS WITHIN VARIOUS ACOUSTIC THRESHOLD
ZONES
Underwater
Species
Density
Level B
120 dB) 1
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Level A
3 34
California sea lion ......................................................................................
Steller sea lion ...........................................................................................
Harbor seal ................................................................................................
Killer whale (transient) ...............................................................................
Harbor porpoise .........................................................................................
32
1.06
n/a
0.149
0
0
0
0
0
6,630
585
8,580
180
1,170
Total proposed
authorized takes 2
6,630
585
8,580
4 180
1,170
1 The 160-dB acoustic harassment zone associated with impact pile driving would always be subsumed by the 120-dB harassment zone produced by vibratory driving. Therefore, takes are not calculated separately for the two zones.
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32855
2 For species with associated density, density was multiplied by largest ZOI (i.e., 41.4 km). The resulting value was rounded to the nearest
whole number and multiplied by the 195 days of activity. For species with abundance only, that value was multiplied directly by the 195 days of
activity. We assume for reasons described earlier that no takes would result from airborne noise.
3 Figures presented are abundance numbers, not density, and are calculated as the average of average daily maximum numbers per month
(see Tables 12–13). Abundance numbers are rounded to the nearest whole number for take estimation. The Steller sea lion abundance was increased to three for take estimation purposes.
4 We assumed that a single pod of six killer whales could be present for as many as 30 days of the duration.
Analyses and Preliminary
Determinations
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Negligible Impact Analysis
NMFS has defined ‘‘negligible
impact’’ in 50 CFR 216.103 as an impact
resulting from the specified activity that
cannot be reasonably expected to, and is
not reasonably likely to, adversely affect
the species or stock through effects on
annual rates of recruitment or survival.
A negligible impact finding is based on
the lack of likely adverse effects on
annual rates of recruitment or survival
(i.e., population-level effects). An
estimate of the number of 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, we
consider other factors, such as the likely
nature of any responses (e.g., intensity,
duration), the context of any responses
(e.g., critical reproductive time or
location, migration), as well as the
number and nature of estimated Level A
harassment takes, the number of
estimated mortalities, and effects on
habitat.
Pile driving activities associated with
the wharf construction project, as
outlined previously, have the potential
to disturb or displace marine mammals.
Specifically, the specified activities may
result in take, in the form of Level B
harassment (behavioral disturbance)
only, from underwater sounds generated
from pile driving. Potential takes could
occur if individuals of these species are
present in the ensonified zone when
pile driving is happening, which is
likely to occur because (1) harbor seals,
which are frequently observed along the
NBKB waterfront, are present within the
WRA; (2) sea lions, which are less
frequently observed, transit the WRA en
route to haul-outs to the south at Delta
Pier; or (3) cetaceans or pinnipeds
transit the larger Level B harassment
zone outside of the WRA.
No injury, serious injury, or mortality
is anticipated given the methods of
installation and measures designed to
minimize the possibility of injury to
marine mammals. The potential for
these outcomes is minimized through
the construction method and the
implementation of the planned
mitigation measures. Specifically,
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vibratory hammers will be the primary
method of installation, and this activity
does not have significant potential to
cause injury to marine mammals due to
the relatively low source levels
produced (likely less than 180 dB rms)
and the lack of potentially injurious
source characteristics. Impact pile
driving produces short, sharp pulses
with higher peak levels and much
sharper rise time to reach those peaks.
When impact driving is necessary,
required measures (use of a sound
attenuation system, which reduces
overall source levels as well as
dampening the sharp, potentially
injurious peaks, and implementation of
shutdown zones) significantly reduce
any possibility of injury. Given
sufficient ‘‘notice’’ through use of soft
start (for impact driving), marine
mammals are expected to move away
from a sound source that is annoying
prior to its becoming potentially
injurious. The likelihood that marine
mammal detection ability by trained
observers is high under the
environmental conditions described for
Hood Canal further enables the
implementation of shutdowns to avoid
injury, serious injury, or mortality.
Effects on individuals that are taken
by Level B harassment, on the basis of
reports in the literature as well as
monitoring from past projects at NBKB,
will likely be limited to reactions such
as increased swimming speeds,
increased surfacing time, or decreased
foraging (if such activity were
occurring). Most likely, individuals will
simply move away from the sound
source and be temporarily displaced
from the areas of pile driving, although
even this reaction has been observed
primarily only in association with
impact pile driving. In response to
vibratory driving, harbor seals (which
may be somewhat habituated to human
activity along the NBKB waterfront)
have been observed to orient towards
and sometimes move towards the
sound. Repeated exposures of
individuals to levels of sound that may
cause Level B harassment are unlikely
to result in hearing impairment or to
significantly disrupt foraging behavior.
Thus, even repeated Level B harassment
of some small subset of the overall stock
is unlikely to result in any significant
realized decrease in fitness to those
individuals, and thus would not result
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in any adverse impact to the stock as a
whole. Level B harassment will be
reduced to the level of least practicable
impact through use of mitigation
measures described herein and, if sound
produced by project activities is
sufficiently disturbing, animals are
likely to simply avoid the project area
while the activity is occurring.
For pinnipeds, no rookeries are
present in the project area, there are no
haul-outs other than those provided
opportunistically by man-made objects,
and the project area is not known to
provide foraging habitat of any special
importance (other than is afforded by
the known migration of salmonids
generally along the Hood Canal
shoreline). No cetaceans are expected
within the WRA. The pile driving
activities analyzed here are similar to
other nearby construction activities
within the Hood Canal, including recent
projects conducted by the Navy at the
same location (TPP and EHW–1 pile
replacement project, Years 1–2 of EHW–
2; barge mooring project) as well as
work conducted in 2005 for the Hood
Canal Bridge (SR–104) by the
Washington State Department of
Transportation, which have taken place
with no reported injuries or mortality to
marine mammals, and no known longterm adverse consequences from
behavioral harassment.
In summary, this negligible impact
analysis is founded on the following
factors: (1) The possibility of injury,
serious injury, or mortality may
reasonably be considered discountable;
(2) the anticipated incidences of Level B
harassment consist of, at worst,
temporary modifications in behavior; (3)
the absence of any major rookeries and
only a few isolated and opportunistic
haul-out areas near or adjacent to the
project site; (4) the absence of cetaceans
within the WRA and generally sporadic
occurrence outside the WRA; (5) the
absence of any other known areas or
features of special significance for
foraging or reproduction within the
project area; and (6) the presumed
efficacy of the planned mitigation
measures in reducing the effects of the
specified activity to the level of least
practicable impact. In addition, none of
these stocks are listed under the ESA or
designated as depleted under the
MMPA. All of the stocks for which take
is authorized are thought to be
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increasing or to be within OSP size. In
combination, we believe that these
factors, as well as the available body of
evidence from other similar activities,
including those conducted at the same
time of year and in the same location,
demonstrate that the potential effects of
the specified activity will have only
short-term effects on individuals. The
specified activity is not expected to
impact rates of recruitment or survival
and will therefore not result in
population-level impacts. 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, we
preliminarily find that the total marine
mammal take from Navy’s wharf
construction activities will have a
negligible impact on the affected marine
mammal species or stocks.
Small Numbers Analysis
The numbers of animals authorized to
be taken for Steller and California sea
lions would be considered small relative
to the relevant stocks or populations
(less than one percent for Steller sea
lions and less than three percent for
California sea lions) even if each
estimated taking occurred to a new
individual—an extremely unlikely
scenario. For pinnipeds occurring at the
NBKB waterfront, there will almost
certainly be some overlap in individuals
present day-to-day. Further, for the
pinniped species, these takes could
potentially occur only within some
small portion of the overall regional
stock. For example, of the estimated
296,500 California sea lions, only
certain adult and subadult males—
believed to number approximately
3,000–5,000 by Jeffries et al. (2000)—
travel north during the non-breeding
season. That number has almost
certainly increased with the population
of California sea lions—the 2000 SAR
for California sea lions reported an
estimated population size of 204,000–
214,000 animals—but likely remains a
relatively small portion of the overall
population.
For harbor seals, animals found in
Hood Canal belong to a closed, resident
population estimated at approximately
1,000 animals by Jeffries et al. (2003),
and takes are likely to occur only within
some portion of that closed population,
rather than to animals from the
Washington inland waters stock as a
whole. The animals that are resident to
Hood Canal, to which any incidental
take would accrue, represent only seven
percent of the best estimate of regional
stock abundance. For transient killer
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whales, we estimate take based on an
assumption that a single pod of whales,
comprising six individuals, is present in
the vicinity of the project area for the
entire duration of the project. These six
individuals represent a small number of
transient killer whales, for which a
conservative minimum estimate of 243
animals is given in the draft 2013 SAR.
Little is known about harbor porpoise
use of Hood Canal, and prior to
monitoring associated with recent pile
driving projects at NBKB, it was
believed that harbor porpoises were
infrequent visitors to the area. It is
unclear from the limited information
available what relationship harbor
porpoise occurrence in Hood Canal may
hold to the regional stock or whether
similar usage of Hood Canal may be
expected to be recurring. It is unknown
how many unique individuals are
represented by sightings in Hood Canal,
although it is unlikely that these
animals represent a large proportion of
the overall stock. While we believe that
the authorized numbers of incidental
take would be likely to occur to a much
smaller number of individuals, the
number of incidents of take relative to
the stock abundance (approximately
eleven percent) remains within the
bounds of what we consider to be small
numbers.
As summarized here, the estimated
numbers of potential incidents of
harassment for these species are likely
much higher than will realistically
occur. This is because (1) we use the
maximum possible number of days
(195) in estimating take, despite the fact
that multiple delays and work stoppages
are likely to result in a lower number of
actual pile driving days; (2) sea lion
estimates rely on the averaged
maximum daily abundances per month,
rather than simply an overall average
which would provide a much lower
abundance figure; and (3) the estimates
for transient killer whales use sparse
information to attempt to account for
the potential presence of species that
have not been observed in Hood Canal
since 2005. In addition, potential
efficacy of mitigation measures in terms
of reduction in numbers and/or
intensity of incidents of take has not
been quantified. Therefore, these
estimated take numbers are likely to be
precautionary. 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, we preliminarily find that
small numbers of marine mammals will
be taken relative to the populations of
the affected species or stocks.
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Fmt 4701
Sfmt 4703
Impact on Availability of Affected
Species for Taking for Subsistence Uses
There are no relevant subsistence uses
of marine mammals implicated by this
action. Therefore, we have determined
that the total taking of affected species
or stocks would not have an unmitigable
adverse impact on the availability of
such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
No marine mammal species listed
under the ESA are expected to be
affected by these activities. Therefore,
we have determined that a section 7
consultation under the ESA is not
required.
National Environmental Policy Act
(NEPA)
In compliance with the NEPA of 1969
(42 U.S.C. 4321 et seq.), as implemented
by the regulations published by the
Council on Environmental Quality
(CEQ; 40 CFR parts 1500–1508), the
Navy prepared an Environmental
Impact Statement (EIS) and issued a
Record of Decision (ROD) for this
project. We acted as a cooperating
agency in the preparation of that
document, and reviewed the EIS and the
public comments received and
determined that preparation of
additional NEPA analysis was not
necessary. In compliance with NEPA,
the CEQ regulations, and NOAA
Administrative Order 216–6, we
subsequently adopted the Navy’s EIS
and issued our own ROD for the
issuance of the first IHA on July 6, 2012,
and reaffirmed the ROD before issuing
a second IHA in 2013.
We have reviewed the Navy’s
application for a renewed IHA for
ongoing construction activities for
2014–15 and the 2013–14 monitoring
report. Based on that review, we have
determined that the proposed action is
very similar to that considered in the
previous IHAs. In addition, no
significant new circumstances or
information relevant to environmental
concerns have been identified. Thus, we
have determined preliminarily that the
preparation of a new or supplemental
NEPA document is not necessary, and
will, after review of public comments
determine whether or not to reaffirm our
2012 ROD. The 2012 NEPA documents
are available for review at https://
www.nmfs.noaa.gov/pr/permits/
incidental.htm.
Proposed Authorization
As a result of these preliminary
determinations, we propose to issue an
IHA to the Navy for conducting the
described wharf construction activities
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in the Hood Canal, from July 16, 2014
through February 15, 2015, provided the
previously mentioned mitigation,
monitoring, and reporting requirements
are incorporated. The proposed IHA
language is provided next.
This section contains a draft of the
IHA itself. The wording contained in
this section is proposed for inclusion in
the IHA (if issued).
1. This Incidental Harassment
Authorization (IHA) is valid from July
16, 2014 through February 15, 2015.
2. This IHA is valid only for pile
driving and removal activities
associated with construction of
Explosive Handling Wharf #2 (EHW–2)
in the Hood Canal, Washington.
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3. General Conditions
(a) A copy of this IHA must be in the
possession of the Navy, its designees,
and work crew personnel operating
under the authority of this IHA.
(b) The species authorized for taking
are the harbor seal (Phoca vitulina),
California sea lion (Zalophus
californianus), killer whale (transient
only; Orcinus orca), Steller sea lion
(Eumetopias jubatus), and the harbor
porpoise (Phocoena phocoena).
(c) The taking, by Level B harassment
only, is limited to the species listed in
condition 3(b). See Table 1 (attached)
for numbers of take authorized.
(d) The taking by injury (Level A
harassment), serious injury, or death of
any of the species listed in condition
3(b) of the Authorization or any taking
of any other species of marine mammal
is prohibited and may result in the
modification, suspension, or revocation
of this IHA.
(e) The Navy shall conduct briefings
between construction supervisors and
crews, marine mammal monitoring
team, and Navy staff prior to the start of
all pile driving activity, and when new
personnel join the work, in order to
explain responsibilities, communication
procedures, marine mammal monitoring
protocol, and operational procedures.
4. Mitigation Measures
In order to ensure the least practicable
impact on the species listed in
condition 3(b), the holder of this
Authorization is required to implement
the following mitigation measures:
(a) During impact pile driving, the
Navy shall implement a minimum
shutdown zone of 20 m radius around
the pile, to be effective for all species of
pinniped, and a minimum shutdown
zone of 85 m radius around the pile, to
be effective for all species of cetacean.
If a marine mammal comes within the
relevant zone, such operations shall
cease. No marine mammal shall be
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exposed to sound pressure levels
equaling or exceeding 180/190 dB rms
(re 1 mPa) for cetaceans and pinnipeds,
respectively, in order to prevent
unauthorized Level A harassment.
(b) During vibratory pile driving and
removal, the Navy shall implement a
minimum shutdown zone of 10 m
radius around the pile for marine
mammals. If a marine mammal comes
within this zone, such operations shall
cease. No marine mammal shall be
exposed to sound pressure levels
equaling or exceeding 180/190 dB rms
(re 1 mPa) for cetaceans and pinnipeds,
respectively, in order to prevent
unauthorized Level A harassment.
(c) The Navy shall similarly avoid
direct interaction with marine mammals
during in-water heavy machinery work
other than pile driving that may occur
in association with the wharf
construction project. If a marine
mammal comes within 10 m of such
activity, operations shall cease and
vessels shall reduce speed to the
minimum level required to maintain
steerage and safe working conditions, as
appropriate.
(d) The Navy shall establish
monitoring locations as described in the
Marine Mammal Monitoring Plan
(Monitoring Plan; attached). For all pile
driving activities, a minimum of one
observer shall be assigned to each active
pile driving rig in order to monitor the
shutdown zones, while at least two
additional observers shall be positioned
for optimal monitoring of the
surrounding waters within the
Waterfront Restricted Area (WRA).
These observers shall record all
observations of marine mammals,
regardless of distance from the pile
being driven, as well as behavior and
potential behavioral reactions of the
animals.
(e) Monitoring shall take place from
15 minutes prior to initiation of pile
driving activity through 30 minutes
post-completion of pile driving activity.
Pre-activity monitoring shall be
conducted for 15 minutes to ensure that
the shutdown zone is clear of marine
mammals, and pile driving may
commence when observers have
declared the shutdown zone clear of
marine mammals. In the event of a delay
or shutdown of activity resulting from
marine mammals in the shutdown zone,
animals shall be allowed to remain in
the shutdown zone (i.e., must leave of
their own volition) and their behavior
shall be monitored and documented.
Monitoring shall occur throughout the
time required to drive a pile. The
shutdown zone must be determined to
be clear during periods of good visibility
(i.e., the entire shutdown zone and
PO 00000
Frm 00031
Fmt 4701
Sfmt 4703
32857
surrounding waters within the WRA
must be visible to the naked eye).
(f) If a marine mammal approaches or
enters the shutdown zone, all pile
driving activities at that location shall
be halted (i.e., implementation of
shutdown at one pile driving location
may not necessarily trigger shutdown at
other locations when pile driving is
occurring concurrently). If pile driving
is halted or delayed at a specific
location due to the presence of a marine
mammal, the activity may not
commence or resume until either the
animal has voluntarily left and been
visually confirmed beyond the
shutdown zone or 15 minutes have
passed without re-detection of the
animal.
(g) Monitoring shall be conducted by
qualified observers, as described in the
Monitoring Plan. Trained observers
shall be placed from the best vantage
point(s) practicable to monitor for
marine mammals and implement
shutdown or delay procedures when
applicable through communication with
the equipment operator.
(h) Approved sound attenuation
devices shall be used during impact pile
driving operations. The Navy shall
implement the necessary contractual
requirements to ensure that such
devices are capable of achieving optimal
performance, and that deployment of
the device is implemented properly
such that no reduction in performance
may be attributable to faulty
deployment.
(i) The Navy shall use soft start
techniques recommended by NMFS for
impact pile driving. The soft start
requires contractors to provide an initial
set of strikes from the impact hammer
at reduced energy, followed by a 30second waiting period, then two
subsequent reduced energy strike sets.
Soft start shall be implemented at the
start of each day’s impact pile driving
and at any time following cessation of
impact pile driving for a period of 30
minutes or longer.
(j) Pile driving shall only be
conducted during daylight hours.
5. Monitoring
The holder of this Authorization is
required to conduct marine mammal
monitoring during pile driving activity.
Marine mammal monitoring and
reporting shall be conducted in
accordance with the Monitoring Plan.
(a) The Navy shall collect sighting
data and behavioral responses to pile
driving for marine mammal species
observed in the region of activity during
the period of activity. All observers
shall be trained in marine mammal
identification and behaviors, and shall
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have no other construction related tasks
while conducting monitoring.
(b) For all marine mammal
monitoring, the information shall be
recorded as described in the Monitoring
Plan.
6. Reporting
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The holder of this Authorization is
required to:
(a) Submit a draft report on all marine
mammal monitoring conducted under
the IHA within 90 calendar days of the
end of the in-water work period. A final
report shall be prepared and submitted
within 30 days following resolution of
comments on the draft report from
NMFS. This report must contain the
informational elements described in the
Monitoring Plan, at minimum (see
attached).
(b) Reporting injured or dead marine
mammals:
i. In the unanticipated event that the
specified activity clearly causes the take
of a marine mammal in a manner
prohibited by this IHA, such as an
injury (Level A harassment), serious
injury, or mortality, Navy shall
immediately cease the specified
activities and report the incident to the
Office of Protected Resources (301–427–
8425), NMFS, and the West Coast
Regional Stranding Coordinator (206–
526–6550), NMFS. The report must
include the following information:
A. Time and date of the incident;
B. Description of the incident;
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14:01 Jun 05, 2014
Jkt 232001
C. Environmental conditions (e.g.,
wind speed and direction, Beaufort sea
state, cloud cover, and visibility);
D. Description of all marine mammal
observations in the 24 hours preceding
the incident;
E. Species identification or
description of the animal(s) involved;
F. Fate of the animal(s); and
G. Photographs or video footage of the
animal(s).
Activities shall not resume until
NMFS is able to review the
circumstances of the prohibited take.
NMFS will work with Navy to
determine what measures are necessary
to minimize the likelihood of further
prohibited take and ensure MMPA
compliance. Navy may not resume their
activities until notified by NMFS.
i. In the event that Navy discovers an
injured or dead marine mammal, and
the lead observer determines that the
cause of the injury or death is unknown
and the death is relatively recent (e.g.,
in less than a moderate state of
decomposition), Navy shall immediately
report the incident to the Office of
Protected Resources, NMFS, and the
West Coast Regional Stranding
Coordinator, NMFS.
The report must include the same
information identified in 6(b)(i) of this
IHA. Activities may continue while
NMFS reviews the circumstances of the
incident. NMFS will work with Navy to
determine whether additional
mitigation measures or modifications to
the activities are appropriate.
PO 00000
Frm 00032
Fmt 4701
Sfmt 9990
ii. In the event that Navy discovers an
injured or dead marine mammal, and
the lead observer determines that the
injury or death is not associated with or
related to the activities authorized in the
IHA (e.g., previously wounded animal,
carcass with moderate to advanced
decomposition, scavenger damage),
Navy shall report the incident to the
Office of Protected Resources, NMFS,
and the West Coast Regional Stranding
Coordinator, NMFS, within 24 hours of
the discovery. Navy shall provide
photographs or video footage or other
documentation of the stranded animal
sighting to NMFS.
7. This Authorization may be
modified, suspended or withdrawn if
the holder fails to abide by the
conditions prescribed herein, or if the
authorized taking is having more than a
negligible impact on the species or stock
of affected marine mammals.
Request for Public Comments
We request comment on our analysis,
the draft authorization, and any other
aspect of this Notice of Proposed IHA
for Navy’s wharf construction activities.
Please include with your comments any
supporting data or literature citations to
help inform our final decision on Navy’s
request for an MMPA authorization.
Dated: May 27, 2014.
Perry F. Gayaldo,
Deputy Director, Office of Protected
Resources, National Marine Fisheries Service.
[FR Doc. 2014–12906 Filed 6–5–14; 8:45 am]
BILLING CODE 3510–22–P
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Agencies
[Federal Register Volume 79, Number 109 (Friday, June 6, 2014)]
[Notices]
[Pages 32827-32858]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-12906]
[[Page 32827]]
Vol. 79
Friday,
No. 109
June 6, 2014
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to a Wharf Construction Project; Notice
Federal Register / Vol. 79 , No. 109 / Friday, June 6, 2014 /
Notices
[[Page 32828]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XD282
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Wharf Construction Project
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for
authorization to take marine mammals incidental to construction
activities as part of a wharf construction project. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an incidental harassment authorization (IHA) to the
Navy to incidentally take marine mammals, by Level B Harassment only,
during the specified activity.
DATES: Comments and information must be received no later than July 7,
2014.
ADDRESSES: Comments on the application should be addressed to Jolie
Harrison, Supervisor, Incidental Take Program, Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service. Physical comments should be sent to 1315 East-West Highway,
Silver Spring, MD 20910 and electronic comments should be sent to
ITP.Laws@noaa.gov.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted to the Internet at
www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All
personal identifying information (e.g., name, address) voluntarily
submitted by the commenter may be publicly accessible. Do not submit
confidential business information or otherwise sensitive or protected
information.
FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
An electronic copy of the Navy's application and supporting
documents, as well as a list of the references cited in this document,
may be obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental.htm. In case of problems accessing these documents,
please call the contact listed above (see FOR FURTHER INFORMATION
CONTACT).
National Environmental Policy Act (NEPA)
The Navy prepared an Environmental Impact Statement (EIS) for this
project. We acted as a cooperating agency on development of that
analysis and subsequently adopted the EIS and issued our own Record of
Decision (ROD; 2012), prior to issuing the first IHA for this project,
in accordance with NEPA and the regulations published by the Council on
Environmental Quality. We reaffirmed the existing 2012 ROD before
issuing an IHA in 2013 for the second year of project construction.
Information in the Navy's application, the Navy's EIS (2012), and this
notice collectively provide the environmental information related to
proposed issuance of this IHA for public review and comment. All
documents are available at the aforementioned Web site, with the
exception of the Navy's EIS, which is publicly available at
www.nbkeis.com (accessed May 2, 2014). We will review all comments
submitted in response to this notice as we complete the NEPA process,
including a decision of whether to reaffirm the existing ROD, prior to
a final decision on the incidental take authorization request.
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 by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified area, the incidental, but not intentional,
taking of small numbers of marine mammals, providing that certain
findings are made and the necessary prescriptions are established.
The incidental taking of small numbers of marine mammals may be
allowed only if NMFS (through authority delegated by the Secretary)
finds that the total taking by the specified activity during the
specified time period will (i) have a negligible impact on the species
or stock(s) and (ii) not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant). Further, the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such taking
must be set forth, either in specific regulations or in an
authorization.
The allowance of such incidental taking under section 101(a)(5)(A),
by harassment, serious injury, death, or a combination thereof,
requires that regulations be established. Subsequently, a Letter of
Authorization may be issued pursuant to the prescriptions established
in such regulations, providing that the level of taking will be
consistent with the findings made for the total taking allowable under
the specific regulations. Under section 101(a)(5)(D), NMFS may
authorize such incidental taking by harassment only, for periods of not
more than one year, pursuant to requirements and conditions contained
within an IHA. The establishment of prescriptions through either
specific regulations or an authorization requires notice and
opportunity for public comment.
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. Except with respect to certain activities not pertinent here,
section 3(18) of the MMPA defines ``harassment'' as any act of pursuit,
torment, or annoyance which has the potential to injure a marine mammal
or marine mammal stock in the wild; or 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. The former is
termed Level A harassment and the latter is termed Level B harassment.
Summary of Request
On January 10, 2014, we received a request from the Navy for
authorization to take marine mammals incidental to pile driving
associated with the construction of an explosives handling wharf (EHW-
2) in the Hood Canal at Naval Base Kitsap in Bangor, WA (NBKB). The
Navy submitted a revised version of the request on April 11, 2014,
which we deemed adequate and complete. The Navy proposes to continue
this multi-year project, involving impact and vibratory pile driving
conducted within the approved
[[Page 32829]]
in-water work window. This IHA would cover only the third year (in-
water work window) of the project, from July 16, 2014, through February
15, 2015.
The use of both vibratory and impact pile driving is expected to
produce underwater sound at levels that have the potential to result in
behavioral harassment of marine mammals. Species with the expected
potential to be present during all or a portion of the in-water work
window include the Steller sea lion (Eumetopias jubatus monteriensis),
California sea lion (Zalophus californianus), harbor seal (Phoca
vitulina richardii), killer whale (transient only; Orcinus orca), and
harbor porpoise (Phocoena phocoena vomerina). These species may occur
year-round in the Hood Canal, with the exception of the Steller sea
lion, which is present only from fall to late spring (approximately
late September to early May), and the California sea lion, which is
only present from late summer to late spring (approximately late August
to early June).
This would be the third such IHA, if issued. The Navy received
IHAs, effective from July 16-February 15, in 2012-13 (77 FR 42279) and
2013-14 (78 FR 43148). Additional IHAs were issued to the Navy in
recent years for marine construction projects on the NBKB waterfront.
These projects include the Test Pile Project (TPP), conducted in 2011-
12 in the proposed footprint of the EHW-2 to collect geotechnical data
and test methodology in advance of EHW-2 (76 FR 38361); a two-year
maintenance project on the existing explosives handling wharf (EHW-1)
conducted in 2011-12 and 2012-13 (76 FR 30130 and 77 FR 43049); and a
minor project to install a new mooring for an existing research barge,
conducted in 2013-14 (78 FR 43165). In-water work associated with all
projects was conducted only during the approved in-water work window
(July 16-February 15). Monitoring reports for all of these projects are
available on the Internet at www.nmfs.noaa.gov/pr/permits/incidental.htm and provide environmental information related to
proposed issuance of this IHA for public review and comment.
Description of the Specified Activity
Overview
NBKB provides berthing and support services to Navy submarines and
other fleet assets. The Navy proposes to continue construction of the
EHW-2 facility at NBKB in order to support future program requirements
for submarines berthed at NBKB. The Navy has determined that
construction of EHW-2 is necessary because the existing EHW alone will
not be able to support future program requirements. All piles would be
driven with a vibratory hammer for their initial embedment depths,
while select piles may be finished with an impact hammer for proofing,
as necessary. A maximum of three vibratory drivers and one impact
driver may be used simultaneously. Proofing involves striking a driven
pile with an impact hammer to verify that it provides the required
load-bearing capacity, as indicated by the number of hammer blows per
foot of pile advancement. Sound attenuation measures (i.e., bubble
curtain) would be used during all impact hammer operations.
Dates and Duration
The allowable season for in-water work, including pile driving, at
NBKB is July 16 through February 15, a window established by the
Washington Department of Fish and Wildlife in coordination with NMFS
and the U.S. Fish and Wildlife Service (USFWS) to protect juvenile
salmon. Under the proposed action--which includes only the portion of
the project that would be completed under this proposed IHA--a maximum
of 195 pile driving days would occur. Pile driving may occur on any day
during the in-water work window.
Impact pile driving during the first half of the in-water work
window (July 16 to September 15) may only occur between two hours after
sunrise and two hours before sunset to protect breeding marbled
murrelets (an Endangered Species Act [ESA]-listed bird under the
jurisdiction of USFWS). Vibratory driving during the first half of the
window, and all in-water work conducted between September 16 and
February 15, may occur during daylight hours (sunrise to sunset). Other
construction (not in-water) may occur between 7:00 a.m. and 10:00 p.m.,
year-round. Therefore, in-water work is restricted to daylight hours
(at minimum) and there is at least a nine-hour break during the 24-hour
cycle from all construction activity.
Specific Geographic Region
NBKB is located on the Hood Canal approximately 32 km west of
Seattle, Washington (see Figures 2-1 through 2-4 in the Navy's
application). The Hood Canal is a long, narrow fjord-like basin of the
western Puget Sound. Throughout its 108-km length, the width of the
canal varies from 1.6-3.2 km and exhibits strong depth/elevation
gradients and irregular seafloor topography in many areas. Although no
official boundaries exist along the waterway, the northeastern section
extending from the mouth of the canal at Admiralty Inlet to the
southern tip of Toandos Peninsula is referred to as northern Hood
Canal. NBKB is located within this region. Please see Section 2 of the
Navy's application for detailed information about the specific
geographic region, including physical and oceanographic
characteristics.
Detailed Description of Activities
Development of necessary facilities for handling of explosive
materials is part of the Navy's sea-based strategic deterrence mission.
The EHW-2 consists of two components: (1) The wharf proper (or
Operations Area), including the warping wharf; and (2) two access
trestles. Please see Figures 1-1 and 1-2 of the Navy's application for
conceptual and schematic representations of the EHW-2.
The wharf proper will lie approximately 183 m offshore at water
depths of 18-30 m, and will consist of the main wharf, a warping wharf,
and lightning protection towers, all pile-supported. It will include a
slip (docking area) for submarines, surrounded on three sides by
operational wharf area. The access trestles will connect the wharf to
the shore. There will be an entrance trestle and an exit trestle; these
will be combined over shallow water to reduce overwater area. The
trestles will be pile-supported on 24-in steel pipe piles driven
approximately 9 m into the seafloor. Spacing between bents (rows of
piles) will be 8 m. Concrete pile caps will be cast in place and will
support pre-cast concrete deck sections.
For the entire project, a total of up to 1,250 permanent piles
ranging in size between 24-48 inches in diameter will be driven in-
water to construct the wharf. Construction also requires temporary
installation of up to 150 falsework piles used as an aid to guide
permanent piles to their proper locations. Falsework piles, which are
removed upon installation of the permanent piles, are usually steel
pipe piles and are driven and removed using a vibratory driver. It has
not been determined exactly what parts or how much of the project will
be constructed in any given year; however, a maximum of 195 days of
pile driving may occur per in-water work window. The analysis contained
herein is based upon the maximum of 195 pile driving days, rather than
any specific number of piles driven. Table 1 summarizes the number and
nature of piles required for the entire project, rather than what
subset of piles may be expected to be driven
[[Page 32830]]
during the third year of construction proposed for this IHA.
Table 1--Summary of Piles Required for Wharf Construction
[in total]
------------------------------------------------------------------------
Feature Quantity
------------------------------------------------------------------------
Total number of permanent in-water Up to 1,250.
piles.
Size and number of main wharf piles.... 24-in: 140.
36-in: 157.
48-in: 263.
Size and number of warping wharf piles. 24-in: 80.
36-in: 190.
Size and number of lightning tower 24-in: 40.
piles. 36-in: 90.
Size and number of trestle piles....... 24-in: 57.
36-in: 233.
Falsework piles........................ Up to 150, 18- to 24-in.
Maximum pile driving duration.......... 195 days (under one-year IHA).
------------------------------------------------------------------------
Pile installation will utilize vibratory pile drivers to the
greatest extent possible, and the Navy anticipates that most piles will
be able to be vibratory driven to within several feet of the required
depth. Pile drivability is, to a large degree, a function of soil
conditions and the type of pile hammer. The soil conditions encountered
during geotechnical explorations at NBKB indicate existing conditions
generally consist of fill or sediment of very dense glacially
overridden soils. Recent experience at other construction locations
along the NBKB waterfront indicates that most piles should be able to
be driven with a vibratory hammer to proper embedment depth. However,
difficulties during pile driving may be encountered as a result of
obstructions, such as rocks or boulders, which may exist throughout the
project area. If difficult driving conditions occur, increased usage of
an impact hammer will occur.
Unless difficult driving conditions are encountered, an impact
hammer will only be used to proof the load-bearing capacity of
approximately every fourth or fifth pile. The industry standard is to
proof every pile with an impact hammer; however, in an effort to reduce
blow counts from the impact hammer, the engineer of record has agreed
to only proof every fourth or fifth pile. A maximum of 200 strikes
would be required to proof each pile. Pile production rates are
dependent upon required embedment depths, the potential for
encountering difficult driving conditions, and the ability to drive
multiple piles without a need to relocate the driving rig. Under best-
case scenarios (i.e., shallow piles, driving in optimal conditions,
using multiple driving rigs), it may be possible to install enough
pilings with the vibratory hammer that proofing may be required for up
to five piles in a day. Under this scenario, with a single impact
hammer used to proof up to five piles per day at 200 strikes per pile,
it is estimated that up to a maximum of 1,000 strikes from an impact
hammer would be required per day.
If difficult subsurface driving conditions (e.g., cobble/boulder
zones) are encountered that cause refusal with the vibratory equipment,
it may be necessary to use an impact hammer to drive some piles for the
remaining portion of their required depth. The worst-case scenario is
that a pile would be driven for its entire length using an impact
hammer. Given the uncertainty regarding the types and quantities of
boulders or cobbles that may be encountered, and the depth at which
they may be encountered, the number of strikes necessary to drive a
pile its entire length could be approximately 1,000 to 2,000 strikes
per pile. The Navy estimates that a possible worst-case daily scenario
would require driving three piles full length (at a worst-case of 2,000
strikes per pile) after the piles have become hung on large boulders
early in the installation process, with proofing of an additional two
piles (at 200 strikes each) that were able to be installed primarily
via vibratory means. This worst-case scenario would therefore result in
a maximum of 6,400 strikes per day. All piles driven or struck with an
impact hammer would be surrounded by a bubble curtain over the full
water column to minimize in-water sound. Up to three vibratory rigs and
one impact rig may be used at a time. Pile production rate (number of
piles driven per day) is affected by many factors: Size, type (vertical
versus angled), and location of piles; weather; number of driver rigs
operating; equipment reliability; geotechnical (subsurface) conditions;
and work stoppages for security or environmental reasons (such as
presence of marine mammals).
Description of Work Accomplished--During the first in-water work
season, the contractor completed installation of 184 piles to support
the main segment of the access trestle. Driven piles ranged in size
from 24- to 36-in at depths ranging from 0 to 15 m. A maximum of two
vibratory pile drivers and one impact hammer were operated
concurrently.
During the second season, installation of 411 total piles was
completed, including all 315 of the wharf deck plumb piles (non-fender)
and 24 of the 34 total wharf deck Lead Rubber Bearing (LRB) dolphins
(clusters of four piles per dolphin). Installed piles ranged in size
from 36- to 48-in at depths ranging from 12-29 m. As before, a maximum
two vibratory pile drivers and one impact hammer were operated
concurrently.
During the third season, the Navy expects to complete installation
of the wharf deck LRBs, piling support for the warping wharf, lightning
towers, and trestle deck closure as well as all fender piles. The Navy
expects to complete the project in January 2016. The amount of progress
made under this proposed IHA, if issued, would determine necessity of a
fourth IHA for the 2015-16 in-water work window.
Description of Marine Mammals in the Area of the Specified Activity
There are eight marine mammal species with recorded occurrence in
the Hood Canal during the past fifteen years, including five cetaceans
and three pinnipeds. The harbor seal resides year-round in Hood Canal,
while the Steller sea lion and California sea lion inhabit Hood Canal
during portions of the year. Harbor porpoises may transit through the
project area and occur regularly in Hood Canal, while transient killer
whales could be present in the project area but do not have regular
occurrence in the Hood Canal. The Dall's porpoise (Phocoenoides dalli
dalli), humpback whale (Megaptera novaeangliae), and gray whale
(Eschrichtius robustus) have been observed in Hood Canal, but their
presence is sufficiently rare that we do not believe there is a
reasonable likelihood of their occurrence in the project area during
the proposed period of validity for this IHA. The latter three species
are not carried forward for further analysis beyond this section.
We have reviewed the Navy's detailed species descriptions,
including life history information, for accuracy and completeness and
refer the reader to Sections 3 and 4 of the Navy's application instead
of reprinting the information here. Please also refer to NMFS' Web site
(www.nmfs.noaa.gov/pr/species/mammals) for generalized species accounts
and to the Navy's Marine Resource Assessment for the Pacific Northwest,
which documents and describes the marine resources that occur in Navy
operating areas of the Pacific Northwest, including Puget Sound (DoN,
2006). The document is publicly available at www.navfac.navy.mil/products_and_services/ev/products_and_services/marine_resources/marine_resource_assessments.html (accessed May 2, 2014).
[[Page 32831]]
Table 2 lists the marine mammal species with expected potential for
occurrence in the vicinity of NBKB during the project timeframe and
summarizes key information regarding stock status and abundance.
Taxonomically, we follow Committee on Taxonomy (2014). Please see NMFS'
Stock Assessment Reports (SAR), available at www.nmfs.noaa.gov/pr/sars,
for more detailed accounts of these stocks' status and abundance. The
harbor seal, California sea lion and harbor porpoise are addressed in
the Pacific SARs (e.g., Carretta et al., 2013a), while the Steller sea
lion and transient killer whale are treated in the Alaska SARs (e.g.,
Allen and Angliss, 2013a).
In the species accounts provided here, we offer a brief
introduction to the species and relevant stock as well as available
information regarding population trends and threats, and describe any
information regarding local occurrence.
Table 2--Marine Mammals Potentially Present in the Vicinity of NBKB
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance (CV,
ESA/MMPA status; Nmin, most recent Annual M/ Relative occurrence in
Species Stock strategic (Y/N) \1\ abundance survey) PBR \3\ SI \4\ Hood Canal; season of
\2\ occurrence
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale...................... West coast --;N................. 243 (n/a; 2006)..... 2.4 0 Rare; year-round (but
transient.\5\ \6\ last observed in 2005).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise................... Washington inland --;N................. 10,682 (0.38; 7,841; 63 >=2.2 Possible regular
waters.\7\ 2003). presence; year-round.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion............... U.S.................. --; N................ 296,750 (n/a; 9,200 >=431 Seasonal/common; Fall to
153,337; 2008). late spring (Aug to
Jun).
Steller sea lion.................. Eastern U.S.\5\...... --; N \8\............ 63,160-78,198 (n/a; \10\ 1,552 65.1 Seasonal/occasional; Fall
57,966; 2008-11) to late spring (Sep to
\9\. May).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal....................... Washington inland --; N................ 14,612 (0.15; 771 13.4 Common; Year-round
waters.\7\ 12,844; 1999). resident.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (--) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see
footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For killer whales, the
abundance values represent direct counts of individually identifiable animals; therefore there is only a single abundance estimate with no associated
CV. For certain stocks of pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction
factor derived from knowledge of the specie's (or similar species') life history to arrive at a best abundance estimate; therefore, there is no
associated CV. In these cases, the minimum abundance may represent actual counts of all animals ashore.
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value. All
values presented here are from the draft 2013 SARs (www.nmfs.noaa.gov/pr/sars/draft.htm).
\5\ Abundance estimates (and resulting PBR values) for these stocks are new values presented in the draft 2013 SARs. This information was made available
for public comment and is currently under review and therefore may be revised prior to finalizing the 2013 SARs. However, we consider this information
to be the best available for use in this document.
\6\ The abundance estimate for this stock includes only animals from the ``inner coast'' population occurring in inside waters of southeastern Alaska,
British Columbia, and Washington--excluding animals from the ``outer coast'' subpopulation, including animals from California--and therefore should be
considered a minimum count. For comparison, the previous abundance estimate for this stock, including counts of animals from California that are now
considered outdated, was 354.
\7\ Abundance estimates for these stocks are greater than eight years old and are therefore not considered current. PBR is considered undetermined for
these stocks, as there is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates
and PBR values, as these represent the best available information for use in this document.
[[Page 32832]]
\8\ The eastern distinct population segment of the Steller sea lion, previously listed under the ESA as threatened, was delisted on December 4, 2013 (78
FR 66140; November 4, 2013). Because this stock is not below its OSP size and the level of direct human-caused mortality does not exceed PBR, this
delisting action implies that the stock is no longer designated as depleted or as a strategic stock under the MMPA.
\9\ Best abundance is calculated as the product of pup counts and a factor based on the birth rate, sex and age structure, and growth rate of the
population. A range is presented because the extrapolation factor varies depending on the vital rate parameter resulting in the growth rate (i.e.,
high fecundity or low juvenile mortality).
\10\ PBR is calculated for the U.S. portion of the stock only (excluding animals in British Columbia) and assumes that the stock is not within its OSP.
If we assume that the stock is within its OSP, PBR for the U.S. portion increases to 2,069.
Although present in Washington inland waters in small numbers
(Falcone et al., 2005), primarily in the Strait of Juan de Fuca and San
Juan Islands but also occasionally in Puget Sound, the humpback whale
is not typically present in Hood Canal. Archived sighting records show
no confirmed observations from 2001-11 (www.orcanetwork.org; accessed
May 5, 2014), and no records are found in the literature. In January-
February 2012, one individual was observed in Hood Canal repeatedly
over a period of several weeks. No sightings have been recorded since
that time.
Gray whales generally migrate southbound past Washington in late
December and January, and transit past Washington on the northbound
return in March to May. Gray whales do not generally make use of
Washington inland waters, but have been observed in certain portions of
those waters in all months of the year, with most records occurring
from March through June (Calambokidis et al., 2010;
www.orcanetwork.org) and associated with regular feeding areas. Usually
fewer than twenty gray whales visit the inner marine waters of
Washington and British Columbia beginning in about January, and six to
ten of these are individual whales that return most years to feeding
sites in northern Puget Sound. The remaining individuals occurring in
any given year generally appear unfamiliar with feeding areas, often
arrive emaciated, and commonly die of starvation (WDFW, 2012). Gray
whales have been sighted in Hood Canal on six occasions since 1999
(including a stranded whale), with the most recent report in November
2010 (www.orcanetwork.org).
In Washington, Dall's porpoises are most abundant in offshore
waters where they are year-round residents, although interannual
distribution is highly variable (Green et al., 1992). In inland waters,
Dall's porpoises are most frequently observed in the Strait of Juan de
Fuca and Haro Strait between San Juan Island and Vancouver Island
(Nysewander et al., 2005), but are seen occasionally in southern Puget
Sound and may also occasionally occur in Hood Canal. Only a single
Dall's porpoise has been observed at NBKB, in deeper water during a
2008 summer survey conducted by the Navy (Tannenbaum et al., 2009). On
the basis of this single observation, we previously assumed it
appropriate to authorize incidental take of this species. However,
there have been no subsequent observations of Dall's porpoises in Hood
Canal during either dedicated vessel line-transect surveys or project-
specific monitoring and we no longer believe that the species may be
reasonably expected to be present in the action area.
Steller Sea Lion
Steller sea lions are distributed mainly around the coasts to the
outer continental shelf along the North Pacific rim from northern
Hokkaido, Japan through the Kuril Islands and Okhotsk Sea, Aleutian
Islands and central Bering Sea, southern coast of Alaska and south to
California (Loughlin et al., 1984). Based on distribution, population
response, and phenotypic and genotypic data, two separate stocks of
Steller sea lions are recognized within U.S. waters, with the
population divided into western and eastern distinct population
segments (DPS) at 144[deg]W (Cape Suckling, Alaska) (Loughlin, 1997).
The eastern DPS extends from California to Alaska, including the Gulf
of Alaska, and is the only stock that may occur in the Hood Canal.
According to NMFS' recent status review (NMFS, 2013), the best
available information indicates that the overall abundance of eastern
DPS Steller sea lions has increased for a sustained period of at least
three decades while pup production has also increased significantly,
especially since the mid-1990s. Johnson and Gelatt (2012) provided an
analysis of growth trends of the entire eastern DPS from 1979-2010,
indicating that the stock increased during this period at an annual
rate of 4.2 percent (90% CI 3.7-4.6). Most of the overall increase
occurred in the northern portion of the range (southeast Alaska and
British Columbia), but pup counts in Oregon and California also
increased significantly (e.g., Merrick et al., 1992; Sease et al.,
2001; Olesiuk and Trites, 2003; Fritz et al. 2008; Olesiuk, 2008; NMFS,
2008, 2013). In Washington, Pitcher et al. (2007) reported that Steller
sea lions, presumably immature animals and non-breeding adults,
regularly used four haul-outs, including two ``major'' haul-outs (>50
animals). The same study reported that the numbers of sea lions counted
between 1989 and 2002 on Washington haul-outs increased significantly
(average annual rate of 9.2 percent) (Pitcher et al., 2007). Although
the stock size has increased, its status relative to OSP size is
unknown. However, the consistent long-term estimated annual rate of
increase may indicate that the stock is reaching OSP size (Allen and
Angliss, 2013a).
Data from 2005-10 show a total mean annual mortality rate of 5.71
(CV = 0.23) sea lions per year from observed fisheries and 11.25
reported takes per year that could not be assigned to specific
fisheries, for an approximate total from all fisheries of 17 eastern
Steller sea lions (Allen and Angliss, 2013a). In addition,
opportunistic observations and stranding data indicate that an
additional 32 animals are killed or seriously injured each year through
interaction with commercial and recreational troll fisheries and by
entanglement (Allen and Angliss, 2013b). The annual average take for
subsistence harvest in Alaska was 11.9 individuals in 2004-08 (Allen
and Angliss, 2013a). Data on community subsistence harvests is no
longer being collected, and this average is retained as an estimate for
current and future subsistence harvest. Sea lion deaths are also known
to occur because of illegal shooting, vessel strikes, or capture in
research gear and other traps, totaling 4.2 animals per year from 2007-
11 (Allen and Angliss, 2013b). The total annual human-caused mortality
is a minimum estimate because takes via fisheries interactions and
subsistence harvest in Canada are poorly known, although are believed
to be small.
The eastern stock breeds in rookeries located in southeast Alaska,
British Columbia, Oregon, and California. There are no known breeding
rookeries in Washington (Allen and Angliss, 2013a) but eastern stock
Steller sea lions are present year-round along the outer coast of
Washington, including immature animals or non-breeding adults of both
sexes. In 2011, the minimum count for Steller sea lions in Washington
was 1,749 (Allen and Angliss, 2013b), up from 516 in 2001 (Pitcher et
al., 2007).
[[Page 32833]]
In Washington, Steller sea lions primarily occur at haul-out sites
along the outer coast from the Columbia River to Cape Flattery and in
inland waters sites along the Vancouver Island coastline of the Strait
of Juan de Fuca (Jeffries et al., 2000; Olesiuk and Trites, 2003;
Olesiuk, 2008). Numbers vary seasonally in Washington waters with peak
numbers present during the fall and winter months (Jeffries et al.,
2000). Beginning in 2008, Steller sea lions have been observed at NBKB
hauled out on submarines at Delta Pier (located approximately 1.25 km
south of the project site) during fall through spring months, with
September 26 as the earliest documented arrival. When Steller sea lions
are present, there are typically one to four individuals, with a
maximum observed group size of eleven.
Harbor Seal
Harbor seals inhabit coastal and estuarine waters and shoreline
areas of the northern hemisphere from temperate to polar regions. The
eastern North Pacific subspecies is found from Baja California north to
the Aleutian Islands and into the Bering Sea. Multiple lines of
evidence support the existence of geographic structure among harbor
seal populations from California to Alaska (e.g., O'Corry-Crowe et al.,
2003; Temte, 1986; Calambokidis et al., 1985; Kelly, 1981; Brown, 1988;
Lamont, 1996; Burg, 1996). Harbor seals are generally non-migratory,
and analysis of genetic information suggests that genetic differences
increase with geographic distance (Westlake and O'Corry-Crowe, 2002).
However, because stock boundaries are difficult to meaningfully draw
from a biological perspective, three separate harbor seal stocks are
recognized for management purposes along the west coast of the
continental U.S.: (1) Inland waters of Washington (including Hood
Canal, Puget Sound, and the Strait of Juan de Fuca out to Cape
Flattery), (2) outer coast of Oregon and Washington, and (3) California
(Carretta et al., 2013a). Multiple stocks are recognized in Alaska.
Samples from Washington, Oregon, and California demonstrate a high
level of genetic diversity and indicate that the harbor seals of
Washington inland waters possess unique haplotypes not found in seals
from the coasts of Washington, Oregon, and California (Lamont et al.,
1996). Only the Washington inland waters stock may be found in the
project area.
Recent genetic evidence suggests that harbor seals of Washington
inland waters may have sufficient population structure to warrant
division into multiple distinct stocks (Huber et al., 2010, 2012).
Based on studies of pupping phenology, mitochondrial DNA, and
microsatellite variation, Carretta et al. (2013b) suggest division of
the Washington inland waters stock into three new populations, and
present these as prospective stocks: (1) Southern Puget Sound (south of
the Tacoma Narrows Bridge); (2) Washington northern inland waters
(including Puget Sound north of the Tacoma Narrows Bridge, the San Juan
Islands, and the Strait of Juan de Fuca); and (3) Hood Canal. Until
this stock structure is accepted, we consider a single Washington
inland waters stock.
The best available abundance estimate was derived from aerial
surveys of harbor seals in Washington conducted during the pupping
season in 1999, during which time the total numbers of hauled-out seals
(including pups) were counted (Jeffries et al., 2003). Radio-tagging
studies conducted at six locations collected information on harbor seal
haul-out patterns in 1991-92, resulting in a pooled correction factor
(across three coastal and three inland sites) of 1.53 to account for
animals in the water which are missed during the aerial surveys (Huber
et al., 2001), which, coupled with the aerial survey counts, provides
the abundance estimate (see Table 2).
Harbor seal counts in Washington State increased at an annual rate
of six percent from 1983-96, increasing to ten percent for the period
1991-96 (Jeffries et al., 1997). The population is thought to be
stable, and the Washington inland waters stock is considered to be
within its OSP size (Jeffries et al., 2003).
Data from 2007-11 indicate that a minimum of four harbor seals are
killed annually in Washington inland waters commercial fisheries, while
mean annual mortality for recreational fisheries is one seal (Carretta
et al., 2013b). Animals captured east of Cape Flattery are assumed to
belong to this stock. The estimate is considered a minimum because
there are likely additional animals killed in unobserved fisheries and
because not all animals stranding as a result of fisheries interactions
are likely to be recorded. Another 8.4 harbor seals per year are
estimated to be killed as a result of various non-fisheries human
interactions (Carretta et al., 2013b). Tribal subsistence takes of this
stock may occur, but no data on recent takes are available.
Harbor seals are the most abundant marine mammal in Hood Canal,
where they can occur anywhere year-round and are considered resident,
and are the only pinniped that breeds in inland Washington waters
(Jeffries et al., 2003). They are year-round, non-migratory residents,
pup (i.e., give birth) in Hood Canal, and the population is considered
closed, meaning that they do not have much movement outside of Hood
Canal (London, 2006). Surveys in the Hood Canal from the mid-1970s to
2000 show a fairly stable population between 600-1,200 seals, and the
abundance of harbor seals in Hood Canal has likely stabilized at its
carrying capacity of approximately 1,000 seals (Jeffries et al., 2003).
Harbor seals have been consistently sighted during Navy surveys, found
in all marine habitats including nearshore waters and deeper water, and
have been observed hauled out on manmade objects such as buoys (Agness
and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011). Harbor seals were
commonly observed in the water during monitoring conducted for other
projects at NBKB in 2011-13 (HDR, 2012a, 2012b; Hart Crowser, 2013).
There are no known pupping or regular haul-out sites in the project
area, as harbor seals in Hood Canal prefer river deltas and exposed
tidal areas (London, 2006). The closest haul-out to the project area is
approximately 16 km southwest of NBKB at Dosewallips River mouth,
outside the potential area of effect for this project (see Figure 4-1
of the Navy's application). During most of the year, all age and sex
classes (except neonates) occur in the project area throughout the
period of construction activity. Because there are no known regular
pupping sites in the vicinity of the project area, harbor seal neonates
would not generally be expected to be present during pile driving.
However, pupping has been observed on the NBKB waterfront at Carderock
Pier and Service Pier (both locations over a mile south of the project
site), and a harbor seal neonate was observed on a small floating dock
near the project site in 2013.
California Sea Lion
California sea lions range from the Gulf of California north to the
Gulf of Alaska, with breeding areas located in the Gulf of California,
western Baja California, and southern California. Five genetically
distinct geographic populations have been identified: (1) Pacific
temperate, (2) Pacific subtropical, and (3-5) southern, central, and
northern Gulf of California (Schramm et al., 2009). Rookeries for the
Pacific temperate population are found within U.S. waters and just
south of the U.S.-Mexico border, and animals belonging to this
population may be found from the Gulf of Alaska to
[[Page 32834]]
Mexican waters off Baja California. For management purposes, a stock of
California sea lions comprising those animals at rookeries within the
U.S. is defined (i.e., the U.S. stock of California sea lions)
(Carretta et al., 2013a). Pup production at the Coronado Islands
rookery in Mexican waters is considered an insignificant contribution
to the overall size of the Pacific temperate population (Lowry and
Maravilla-Chavez, 2005).
Trends in pup counts from 1975 through 2008 have been assessed for
four rookeries in southern California and for haul-outs in central and
northern California. During this time period counts of pups increased
at an annual rate of 5.4 percent, excluding six El Nino years when pup
production declined dramatically before quickly rebounding (Carretta et
al., 2013a). The maximum population growth rate was 9.2 percent when
pup counts from the El Ni[ntilde]o years were removed. There are
indications that the California sea lion may have reached or is
approaching carrying capacity, although more data are needed to confirm
that leveling in growth persists (Carretta et al., 2013a).
Data from 2003-09 indicate that a minimum of 337 (CV = 0.56)
California sea lions are killed annually in commercial fisheries. In
addition, a summary of stranding database records for 2005-09 shows an
annual average of 65 such events, which is likely a gross underestimate
because most carcasses are not recovered. California sea lions may also
be removed because of predation on endangered salmonids (seventeen per
year, 2008-10) or incidentally captured during scientific research
(three per year, 2005-09) (Carretta et al., 2013a). Sea lion mortality
has also been linked to the algal-produced neurotoxin domoic acid
(Scholin et al., 2000). Future mortality may be expected to occur, due
to the sporadic occurrence of such harmful algal blooms. There is
currently an Unusual Mortality Event (UME) declaration in effect for
California sea lions. Beginning in January 2013, elevated strandings of
California sea lion pups have been observed in southern California,
with live sea lion strandings nearly three times higher than the
historical average. Findings to date indicate that a likely contributor
to the large number of stranded, malnourished pups was a change in the
availability of sea lion prey for nursing mothers, especially sardines.
The causes and mechanisms of this UME remain under investigation
(www.nmfs.noaa.gov/pr/health/mmume/californiasealions2013.htm; accessed
May 8, 2014).
An estimated 3,000 to 5,000 California sea lions migrate northward
along the coast to central and northern California, Oregon, Washington,
and Vancouver Island during the non-breeding season from September to
May (Jeffries et al., 2000) and return south the following spring
(Mate, 1975; Bonnell et al., 1983). Peak numbers of up to 1,000
California sea lions occur in Puget Sound (including Hood Canal) during
this time period (Jeffries et al., 2000).
California sea lions are present in Hood Canal during much of the
year with the exception of mid-June through August, and occur regularly
at NBKB, as observed during Navy waterfront surveys conducted from
April 2008 through December 2013 (DoN, 2013). They are known to utilize
a diversity of man-made structures for hauling out (Riedman, 1990) and,
although there are no regular California sea lion haul-outs known
within the Hood Canal (Jeffries et al., 2000), they are frequently
observed hauled out at several opportune areas at NBKB (e.g.,
submarines, floating security fence, barges). All documented instances
of California sea lions hauling out at NBKB have been on submarines
docked at Delta Pier, where a maximum of 122 California sea lions have
been observed at any one time (DoN, 2013), and on pontoons of the NBKB
floating security fence.
Killer Whale
Killer whales are one of the most cosmopolitan marine mammals,
found in all oceans with no apparent restrictions on temperature or
depth, although they do occur at higher densities in colder, more
productive waters at high latitudes and are more common in nearshore
waters (Leatherwood and Dahlheim, 1978; Forney and Wade, 2006). Killer
whales are found throughout the North Pacific, including the entire
Alaska coast, in British Columbia and Washington inland waterways, and
along the outer coasts of Washington, Oregon, and California. On the
basis of differences in morphology, ecology, genetics, and behavior,
populations of killer whales have largely been classified as
``resident'', ``transient'', or ``offshore'' (e.g., Dahlheim et al.,
2008). Several studies have also provided evidence that these ecotypes
are genetically distinct, and that further genetic differentiation is
present between subpopulations of the resident and transient ecotypes
(e.g., Barrett-Lennard, 2000). The taxonomy of killer whales is
unresolved, with expert opinion generally following one of two lines:
Killer whales are either (1) a single highly variable species, with
locally differentiated ecotypes representing recently evolved and
relatively ephemeral forms not deserving species status, or (2)
multiple species, supported by the congruence of several lines of
evidence for the distinctness of sympatrically occurring forms (Krahn
et al., 2004). Resident and transient whales are currently considered
to be unnamed subspecies (Committee on Taxonomy, 2014).
The resident and transient populations have been divided further
into different subpopulations on the basis of genetic analyses,
distribution, and other factors. Recognized stocks in the North Pacific
include Alaska residents; northern residents; southern residents; Gulf
of Alaska, Aleutian Islands, and Bering Sea transients; and west coast
transients, along with a single offshore stock. See Allen and Angliss
(2013a) for more detail about these stocks. West coast transient killer
whales, which occur from California through southeastern Alaska, are
the only type expected to potentially occur in the project area.
It is thought that the stock grew rapidly from the mid-1970s to
mid-1990s as a result of a combination of high birth rate, survival, as
well as greater immigration of animals into the nearshore study area
(DFO, 2009). The rapid growth of the population during this period
coincided with a dramatic increase in the abundance of the whales'
primary prey, harbor seals, in nearshore waters. Population growth
began slowing in the mid-1990s and has continued to slow in recent
years (DFO, 2009). Population trends and status of this stock relative
to its OSP level are currently unknown. Analyses in DFO (2009)
estimated a rate of increase of about six percent per year from 1975 to
2006, but this included recruitment of non-calf whales into the
population.
Although certain commercial fisheries are known to have potential
for interaction with killer whales and other mortality, resulting from
shooting, ship strike, or entanglement, has been of concern in the
past, the estimated level of human caused mortality and serious injury
is currently considered to be zero for this stock (Allen and Angliss,
2013a). However, this could represent an underestimate as regards total
fisheries-related mortality due to a lack of data concerning marine
mammal interactions in Canadian commercial fisheries known to have
potential for interaction with killer whales. Any such interactions are
thought to be few in number (Allen and Angliss, 2013a). No ship strikes
have been reported for this stock, and shooting of transients is
[[Page 32835]]
thought to be minimal because their diet is based on marine mammals
rather than fish. There are no reports of a subsistence harvest of
killer whales in Alaska or Canada.
Transient occurrence in inland waters appears to peak during August
and September, which is the peak time for harbor seal pupping, weaning,
and post-weaning (Baird and Dill, 1995). The number of transient killer
whales in Washington waters at any one time is probably fewer than
twenty individuals (Wiles, 2004). In 2003 and 2005, small groups of
transient killer whales (eleven and six individuals, respectively) were
present in Hood Canal for significant periods of time (59 and 172 days,
respectively) between the months of January and July. While present,
the whales preyed on harbor seals in the subtidal zone of the nearshore
marine and inland marine deeper water habitats (London, 2006).
Harbor Porpoise
Harbor porpoises are found primarily in inshore and relatively
shallow coastal waters (<100 m) from Point Barrow (Alaska) to Point
Conception (California). Various genetic analyses and investigation of
pollutant loads indicate a low mixing rate for harbor porpoises along
the west coast of North America and likely fine-scale geographic
structure along an almost continuous distribution from California to
Alaska (e.g., Calambokidis and Barlow, 1991; Osmek et al., 1994;
Chivers et al., 2002, 2007). However, stock boundaries are difficult to
draw because any rigid line is generally arbitrary from a biological
perspective. On the basis of genetic data and density discontinuities
identified from aerial surveys, eight stocks have been identified in
the eastern North Pacific, including northern Oregon/Washington coastal
and inland Washington stocks (Carretta et al., 2013a). The Washington
inland waters stock includes individuals found east of Cape Flattery
and is the only stock that may occur in the project area.
Although long-term harbor porpoise sightings in southern Puget
Sound declined from the 1940s through the 1990s, sightings and
strandings have increased in Puget Sound and northern Hood Canal in
recent years and harbor porpoise are now considered to regularly occur
year-round in these waters (Carretta et al., 2013a). Reasons for the
apparent decline, as well as the apparent rebound, are unknown. Recent
observations may represent a return to historical conditions, when
harbor porpoises were considered one of the most common cetaceans in
Puget Sound (Scheffer and Slipp, 1948). The status of harbor porpoises
in Washington inland waters relative to OSP is not known (Carretta et
al., 2013a).
Data from 2005-09 indicate that a minimum of 2.2 Washington inland
waters harbor porpoises are killed annually in U.S. commercial
fisheries (Carretta et al., 2013a). Animals captured in waters east of
Cape Flattery are assumed to belong to this stock. This estimate is
considered a minimum because the Washington Puget Sound Region salmon
set/drift gillnet fishery has not been observed since 1994, and because
of a lack of knowledge about the extent to which harbor porpoise from
U.S. waters frequent the waters of British Columbia and are, therefore,
subject to fishery-related mortality. However, harbor porpoise takes in
the salmon drift gillnet fishery are unlikely to have increased since
the fishery was last observed, when few interactions were recorded, due
to reductions in the number of participating vessels and available
fishing time. Fishing effort and catch have declined throughout all
salmon fisheries in the region due to management efforts to recover
ESA-listed salmonids (Carretta et al., 2013a). In addition, an
estimated 0.4 animals per year are killed by non-fishery human causes
(e.g., ship strike, entanglement). In 2006, a UME was declared for
harbor porpoises throughout Oregon and Washington, and a total of 114
strandings were reported in 2006-07. The cause of the UME has not been
determined and several factors, including contaminants, genetics, and
environmental conditions, are still being investigated (Carretta et
al., 2013a).
Prior to recent construction projects conducted by the Navy at
NBKB, harbor porpoises were considered to have only occasional
occurrence in the project area. A single harbor porpoise had been
sighted in deeper water at NBKB during 2010 field observations
(Tannenbaum et al., 2011). However, while implementing monitoring plans
for work conducted from July-October, 2011, the Navy recorded multiple
sightings of harbor porpoise in the deeper waters of the project area
(HDR, 2012). Following these sightings, the Navy conducted dedicated
line transect surveys, recording multiple additional sightings of
harbor porpoises, and have revised local density estimates accordingly.
Potential Effects of the Specified Activity on Marine Mammals
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals. This
discussion also includes 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 ``Negligible Impact Analysis'' 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. In the following
discussion, we provide general background information on sound and
marine mammal hearing before considering potential effects to marine
mammals from sound produced by vibratory and impact pile driving.
Description of Sound Sources
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks of a sound wave; lower frequency sounds have
longer wavelengths than higher frequency sounds and attenuate
(decrease) more rapidly in shallower water. Amplitude is the height of
the sound pressure wave or the `loudness' of a sound and is typically
measured using the decibel (dB) scale. A dB is the ratio between a
measured pressure (with sound) and a reference pressure (sound at a
constant pressure, established by scientific standards). It is a
logarithmic unit that accounts for large variations in amplitude;
therefore, relatively small changes in dB ratings correspond to large
changes in sound pressure. When referring to sound pressure levels
(SPLs;
[[Page 32836]]
the sound force per unit area), sound is referenced in the context of
underwater sound pressure to 1 microPascal ([mu]Pa). One pascal is the
pressure resulting from a force of one newton exerted over an area of
one square meter. The source level (SL) represents the sound level at a
distance of 1 m from the source (referenced to 1 [mu]Pa). The received
level is the sound level at the listener's position. Note that all
underwater sound levels in this document are referenced to a pressure
of 1 [mu]Pa and all airborne sound levels in this document are
referenced to a pressure of 20 [mu]Pa.
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Rms is calculated by squaring all of the
sound amplitudes, averaging the squares, and then taking the square
root of the average (Urick, 1983). Rms accounts for both positive and
negative values; squaring the pressures makes all values positive so
that they may be accounted for in the summation of pressure levels
(Hastings and Popper, 2005). This measurement is often used in the
context of discussing behavioral effects, in part because behavioral
effects, which often result from auditory cues, may be better expressed
through averaged units than by peak pressures.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in all
directions away from the source (similar to ripples on the surface of a
pond), except in cases where the source is directional. The
compressions and decompressions associated with sound waves are
detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown sources. These sources may include physical (e.g.,
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
sound (e.g., vessels, dredging, aircraft, construction). A number of
sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient noise for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf noise becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total noise at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient noise levels, as can some fish and shrimp. The frequency band
for biological contributions is from approximately 12 Hz to over 100
kHz.
Anthropogenic: Sources of ambient noise related to human
activity include transportation (surface vessels and aircraft),
dredging and construction, oil and gas drilling and production, seismic
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise
typically dominates the total ambient noise for frequencies between 20
and 300 Hz. In general, the frequencies of anthropogenic sounds are
below 1 kHz and, if higher frequency sound levels are created, they
attenuate rapidly (Richardson et al., 1995). Sound from identifiable
anthropogenic sources other than the activity of interest (e.g., a
passing vessel) is sometimes termed background sound, as opposed to
ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Underwater ambient noise was measured at approximately 113 dB rms
between 50 Hz and 20 kHz during the recent TPP project, approximately
1.85 mi from the project area (Illingworth & Rodkin, 2012). In 2009,
the average broadband ambient underwater noise levels were measured at
114 dB between 100 Hz and 20 kHz (Slater, 2009). Peak spectral noise
from industrial activity was noted below the 300 Hz frequency, with
maximum levels of 110 dB noted in the 125 Hz band. In the 300 Hz to 5
kHz range, average levels ranged between 83 and 99 dB. Wind-driven wave
noise dominated the background noise environment at approximately 5 kHz
and above, and ambient noise levels flattened above 10 kHz. Known sound
levels and frequency ranges associated with anthropogenic sources
similar to those that would be used for this project are summarized in
Table 3. Details of the source types are described in the following
text.
Table 3--Representative Sound Levels of Anthropogenic Sources
----------------------------------------------------------------------------------------------------------------
Frequency range
Sound source (Hz) Underwater sound level Reference
----------------------------------------------------------------------------------------------------------------
Small vessels.......................... 250-1,000 151 dB rms at 1 m........ Richardson et al., 1995.
Tug docking gravel barge............... 200-1,000 149 dB rms at 100 m...... Blackwell and Greene,
2002.
Vibratory driving of 72-in steel pipe 10-1,500 180 dB rms at 10 m....... Reyff, 2007.
pile.
Impact driving of 36-in steel pipe pile 10-1,500 195 dB rms at 10 m....... Laughlin, 2007.
Impact driving of 66-in cast-in-steel- 10-1,500 195 dB rms at 10 m....... Reviewed in Hastings and
shell (CISS) pile. Popper, 2005.
----------------------------------------------------------------------------------------------------------------
[[Page 32837]]
In-water construction activities associated with the project would
include impact pile driving and vibratory pile driving. The sounds
produced by these activities fall into one of two general sound types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al., (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and
occur either as isolated events or repeated in some succession. Pulsed
sounds are all characterized by a relatively rapid rise from ambient
pressure to a maximal pressure value followed by a rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Impact hammers operate by repeatedly dropping a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak SPLs may be
180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals,
and exposure to sound can have deleterious effects. To appropriately
assess these potential effects, it is necessary to understand the
frequency ranges marine mammals are able to hear. Current data indicate
that not all marine mammal species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008). To reflect this, Southall et al. (2007) recommended
that marine mammals be divided into functional hearing groups based on
measured or estimated hearing ranges on the basis of available
behavioral data, audiograms derived using auditory evoked potential
techniques, anatomical modeling, and other data. The lower and/or upper
frequencies for some of these functional hearing groups have been
modified from those designated by Southall et al. (2007). The
functional groups and the associated frequencies are indicated below
(note that these frequency ranges do not necessarily correspond to the
range of best hearing, which varies by species):
Low-frequency cetaceans (mysticetes): Functional hearing
is estimated to occur between approximately 7 Hz and 30 kHz (extended
from 22 kHz; Watkins, 1986; Au et al., 2006; Lucifredi and Stein, 2007;
Ketten and Mountain, 2009; Tubelli et al., 2012);
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Functional hearing is estimated to occur
between approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; now considered to
include two members of the genus Lagenorhynchus on the basis of recent
echolocation data and genetic data [May-Collado and Agnarsson, 2006;
Kyhn et al. 2009, 2010; Tougaard et al. 2010]): Functional hearing is
estimated to occur between approximately 200 Hz and 180 kHz; and
Pinnipeds in water: Functional hearing is estimated to
occur between approximately 75 Hz to 100 kHz for Phocidae (true seals)
and between 100 Hz and 40 kHz for Otariidae (eared seals), with the
greatest sensitivity between approximately 700 Hz and 20 kHz. The
pinniped functional hearing group was modified from Southall et al.
(2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013).
There are five marine mammal species (two cetacean and three
pinniped [two otariid and one phocid] species) with expected potential
to co-occur with Navy construction activities. Please refer to Table 2.
Of the two cetacean species that may be present, the killer whale is
classified as a mid-frequency cetacean and the harbor porpoise is
classified as a high-frequency cetacean.
Acoustic Effects, Underwater
Potential Effects of Pile Driving Sound--The effects of sounds from
pile driving might result in one or more of the following: Temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, and masking (Richardson et al., 1995;
Gordon et al., 2004; Nowacek et al., 2007; Southall et al., 2007). The
effects of pile driving on marine mammals are dependent on several
factors, including the size, type, and depth of the animal; the depth,
intensity, and duration of the pile driving sound; the depth of the
water column; the substrate of the habitat; the standoff distance
between the pile and the animal; and the sound propagation properties
of the environment. Impacts to marine mammals from pile driving
activities are expected to result primarily from acoustic pathways. As
such, the degree of effect is intrinsically related to the received
level and duration of the sound exposure, which are in turn influenced
by the distance between the animal and the source. The further away
from the source, the less intense the exposure should be. The substrate
and depth of the habitat affect the sound propagation properties of the
environment. Shallow environments are typically more structurally
complex, which leads to rapid sound attenuation. In addition,
substrates that are soft (e.g., sand) would absorb or attenuate the
sound more readily than hard substrates (e.g., rock) which may reflect
the acoustic wave. Soft porous substrates would also likely require
less time to drive the pile, and possibly less forceful equipment,
which would ultimately decrease the intensity of the acoustic source.
In the absence of mitigation, impacts to marine species would be
expected to result from physiological and behavioral responses to both
the type and strength
[[Page 32838]]
of the acoustic signature (Viada et al., 2008). The type and severity
of behavioral impacts are more difficult to define due to limited
studies addressing the behavioral effects of impulsive sounds on marine
mammals. Potential effects from impulsive sound sources can range in
severity from effects such as behavioral disturbance or tactile
perception to physical discomfort, slight injury of the internal organs
and the auditory system, or mortality (Yelverton et al., 1973).
Hearing Impairment and Other Physical Effects--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 not recoverable, or
temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Marine mammals depend on
acoustic cues for vital biological functions, (e.g., orientation,
communication, finding prey, avoiding predators); thus, TTS may result
in reduced fitness in survival and reproduction. However, this depends
on the frequency and duration of TTS, as well as the biological context
in which it occurs. TTS of limited duration, occurring in a frequency
range that does not coincide with that used for recognition of
important acoustic cues, would have little to no effect on an animal's
fitness. Repeated sound exposure that leads to TTS could cause PTS. PTS
constitutes injury, but TTS does not (Southall et al., 2007). The
following subsections discuss in somewhat more detail the possibilities
of TTS, PTS, and non-auditory physical effects.
Temporary Threshold Shift--TTS is the mildest form of hearing
impairment that can occur during exposure to a strong sound (Kryter,
1985). While experiencing TTS, the hearing threshold rises, and a sound
must be stronger in order to be heard. In terrestrial mammals, TTS can
last from minutes or hours to days (in cases of strong TTS). For sound
exposures at or somewhat above the TTS threshold, hearing sensitivity
in both terrestrial and marine mammals recovers rapidly after exposure
to the sound ends. Few data on sound levels and durations necessary to
elicit mild TTS have been obtained for marine mammals, and none of the
published data concern TTS elicited by exposure to multiple pulses of
sound. Available data on TTS in marine mammals are summarized in
Southall et al. (2007).
Given the available data, the received level of a single pulse
(with no frequency weighting) might need to be approximately 186 dB re
1 [mu]Pa\2\-s (i.e., 186 dB sound exposure level [SEL] or approximately
221-226 dB p-p [peak]) in order to produce brief, mild TTS. Exposure to
several strong pulses that each have received levels near 190 dB rms
(175-180 dB SEL) might result in cumulative exposure of approximately
186 dB SEL and thus slight TTS in a small odontocete, assuming the TTS
threshold is (to a first approximation) a function of the total
received pulse energy.
The above TTS information for odontocetes is derived from studies
on the bottlenose dolphin (Tursiops truncatus) and beluga whale
(Delphinapterus leucas). There is no published TTS information for
other species of cetaceans. However, preliminary evidence from a harbor
porpoise exposed to pulsed sound suggests that its TTS threshold may
have been lower (Lucke et al., 2009). As summarized above, data that
are now available imply that TTS is unlikely to occur unless
odontocetes are exposed to pile driving pulses stronger than 180 dB re
1 [mu]Pa rms.
Permanent Threshold Shift--When PTS occurs, there is physical
damage to the sound receptors in the ear. In severe cases, there can be
total or partial deafness, while in other cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985). There is no specific evidence that exposure to pulses of sound
can cause PTS in any marine mammal. However, given the possibility that
mammals close to a sound source might incur TTS, there has been further
speculation about the possibility that some individuals might incur
PTS. Single or occasional occurrences of mild TTS are not indicative of
permanent auditory damage, but repeated or (in some cases) single
exposures to a level well above that causing TTS onset might elicit
PTS.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals but are assumed to be similar to those in humans and
other terrestrial mammals. PTS might occur at a received sound level at
least several decibels above that inducing mild TTS if the animal were
exposed to strong sound pulses with rapid rise time. Based on data from
terrestrial mammals, a precautionary assumption is that the PTS
threshold for impulse sounds (such as pile driving pulses as received
close to the source) is at least 6 dB higher than the TTS threshold on
a peak-pressure basis and probably greater than 6 dB (Southall et al.,
2007). On an SEL basis, Southall et al. (2007) estimated that received
levels would need to exceed the TTS threshold by at least 15 dB for
there to be risk of PTS. Thus, for cetaceans, Southall et al. (2007)
estimate that the PTS threshold might be an M-weighted SEL (for the
sequence of received pulses) of approximately 198 dB re 1 [mu]Pa\2\-s
(15 dB higher than the TTS threshold for an impulse). Given the higher
level of sound necessary to cause PTS as compared with TTS, it is
considerably less likely that PTS could occur.
Measured source levels from impact pile driving can be as high as
214 dB rms. Although no marine mammals have been shown to experience
TTS or PTS as a result of being exposed to pile driving activities,
captive bottlenose dolphins and beluga whales exhibited changes in
behavior when exposed to strong pulsed sounds (Finneran et al., 2000,
2002, 2005). The animals tolerated high received levels of sound before
exhibiting aversive behaviors. Experiments on a beluga whale showed
that exposure to a single watergun impulse at a received level of 207
kPa (30 psi) p-p, which is equivalent to 228 dB 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
four minutes of the exposure (Finneran et al., 2002). 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 sound exposure in terms of SEL than from the single watergun
impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the aforementioned
experiment (Finneran et al., 2002). However, in order for marine
mammals to experience TTS or PTS, the animals have to be close enough
to be exposed to high intensity sound levels for a prolonged period of
time. Based on the best scientific information available, these SPLs
are far below the thresholds that could cause TTS or the onset of PTS.
Non-auditory Physiological Effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to strong underwater sound include stress, neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies
examining such effects are limited. In general, little is known about
the potential for pile
[[Page 32839]]
driving to cause auditory impairment or other physical effects in
marine mammals. Available data suggest that such effects, if they occur
at all, would presumably be limited to short distances from the sound
source and to activities that extend over a prolonged period. The
available data do not allow identification of a specific exposure level
above which non-auditory effects can be expected (Southall et al.,
2007) or any meaningful quantitative predictions of the numbers (if
any) of marine mammals that might be affected in those ways. Marine
mammals that show behavioral avoidance of pile driving, including some
odontocetes and some pinnipeds, are especially unlikely to incur
auditory impairment or non-auditory physical effects.
Disturbance Reactions
Disturbance includes a variety of effects, including subtle changes
in behavior, more conspicuous changes in activities, and displacement.
Behavioral responses to sound are highly variable and context-specific
and reactions, if any, depend on species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day, and many other factors (Richardson et al., 1995; Wartzok
et al., 2003; Southall et al., 2007).
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. Behavioral state may affect the type of response as well. For
example, animals that are resting may show greater behavioral change in
response to disturbing sound levels than animals that are highly
motivated to remain in an area for feeding (Richardson et al., 1995;
NRC, 2003; Wartzok et al., 2003).
Controlled experiments with captive marine mammals showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources
(typically seismic guns or acoustic harassment devices, but also
including pile driving) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; Thorson and Reyff, 2006; see also Gordon et al., 2004;
Wartzok et al., 2003; Nowacek et al., 2007). Responses to continuous
sound, such as vibratory pile installation, have not been documented as
well as responses to pulsed sounds.
With both types of pile driving, it is likely that the onset of
pile driving could result in temporary, short term changes in an
animal's typical behavior and/or avoidance of the affected area. These
behavioral changes may include (Richardson et al., 1995): Changing
durations of surfacing and dives, number of blows per surfacing, or
moving direction and/or speed; reduced/increased vocal activities;
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping); avoidance of
areas where sound sources are located; and/or flight responses (e.g.,
pinnipeds flushing into water from haul-outs or rookeries). Pinnipeds
may increase their haul-out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, or reproduction. Significant
behavioral modifications that could potentially lead to effects on
growth, survival, or reproduction include:
Drastic changes in diving/surfacing patterns (such as
those thought to cause beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al., 2007).
Auditory Masking
Natural and artificial sounds can disrupt behavior by masking, or
interfering with, a marine mammal's ability to hear other sounds.
Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher levels. Chronic exposure to excessive, though not high-
intensity, sound could cause masking at particular frequencies for
marine mammals that utilize sound for vital biological functions.
Masking can interfere with detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, under certain circumstances,
marine mammals whose acoustical sensors or environment are being
severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. If the coincident
(masking) sound were man-made, it could be potentially harassing if it
disrupted hearing-related behavior. It is important to distinguish TTS
and PTS, which persist after the sound exposure, from masking, which
occurs during the sound exposure. Because masking (without resulting in
TS) is not associated with abnormal physiological function, it is not
considered a physiological effect, but rather a potential behavioral
effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. Because sound
generated from in-water pile driving is mostly concentrated at low
frequency ranges, it may have less effect on high frequency
echolocation sounds made by porpoises. However, lower frequency man-
made sounds are more likely to affect detection of communication calls
and other potentially important natural sounds such as surf and prey
sound. It may also affect communication signals when they occur near
the sound band and thus reduce the communication space of animals
(e.g., Clark et al., 2009) and cause increased stress levels (e.g.,
Foote et al., 2004; Holt et al., 2009).
Masking has the potential to impact species at the population or
community levels as well as at individual levels. Masking affects both
senders and receivers of the signals and can potentially have long-term
chronic effects on marine mammal species and populations. Recent
research suggests that low frequency ambient sound levels have
increased by as much as 20 dB (more than three times in terms of SPL)
in the world's ocean from pre-industrial periods, and that most of
these increases are from distant shipping (Hildebrand, 2009). All
anthropogenic sound sources, such as those from vessel traffic, pile
driving, and dredging activities, contribute to the elevated ambient
sound levels, thus intensifying masking.
The most intense underwater sounds in the proposed action are those
produced by impact pile driving. Given that the energy distribution of
pile driving covers a broad frequency
[[Page 32840]]
spectrum, sound from these sources would likely be within the audible
range of marine mammals present in the project area. Impact pile
driving activity is relatively short-term, with rapid pulses occurring
for approximately fifteen minutes per pile. The probability for impact
pile driving resulting from this proposed action masking acoustic
signals important to the behavior and survival of marine mammal species
is likely to be negligible. Vibratory pile driving is also relatively
short-term, with rapid oscillations occurring for approximately one and
a half hours per pile. It is possible that vibratory pile driving
resulting from this proposed action may mask acoustic signals important
to the behavior and survival of marine mammal species, but the short-
term duration and limited affected area would result in insignificant
impacts from masking. Any masking event that could possibly rise to
Level B harassment under the MMPA would occur concurrently within the
zones of behavioral harassment already estimated for vibratory and
impact pile driving, and which have already been taken into account in
the exposure analysis.
Acoustic Effects, Airborne
Marine mammals that occur in the project area could be exposed to
airborne sounds associated with pile driving that have the potential to
cause harassment, depending on their distance from pile driving
activities. Airborne pile driving sound would have less impact on
cetaceans than pinnipeds because sound from atmospheric sources does
not transmit well underwater (Richardson et al., 1995); thus, airborne
sound would only be an issue for pinnipeds either hauled-out or looking
with heads above water in the project area. Most likely, airborne sound
would cause behavioral responses similar to those discussed above in
relation to underwater sound. For instance, anthropogenic sound could
cause hauled-out pinnipeds to exhibit changes in their normal behavior,
such as reduction in vocalizations, or cause them to temporarily
abandon their habitat and move further from the source. Studies by
Blackwell et al. (2004) and Moulton et al. (2005) indicate a tolerance
or lack of response to unweighted airborne sounds as high as 112 dB
peak and 96 dB rms.
Anticipated Effects on Habitat
The proposed activities at NBKB would not result in permanent
impacts to habitats used directly by marine mammals, such as haul-out
sites, but may have potential short-term impacts to food sources such
as forage fish and salmonids. There are no rookeries or major haul-out
sites within 16 km or ocean bottom structure of significant biological
importance to marine mammals that may be present in the marine waters
in the vicinity of the project area. Therefore, the main impact
associated with the proposed activity would be temporarily elevated
sound levels and the associated direct effects on marine mammals, as
discussed previously in this document. The most likely impact to marine
mammal habitat occurs from pile driving effects on likely marine mammal
prey (i.e., fish) near NBKB and minor impacts to the immediate
substrate during installation and removal of piles during the wharf
construction project.
Pile Driving Effects on Potential Prey
Construction activities would produce both pulsed (i.e., impact
pile driving) and continuous (i.e., vibratory pile driving) sounds.
Fish react to sounds which are especially strong and/or intermittent
low-frequency sounds. Short duration, sharp sounds can cause overt or
subtle changes in fish behavior and local distribution. Hastings and
Popper (2005) identified several studies that suggest fish may relocate
to avoid certain areas of sound energy. Additional studies have
documented effects of pile driving on fish, although several are based
on studies in support of large, multiyear bridge construction projects
(e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound
pulses at received levels of 160 dB may cause subtle changes in fish
behavior. SPLs of 180 dB may cause noticeable changes in behavior
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient
strength have been known to cause injury to fish and fish mortality.
The most likely impact to fish from pile driving activities at the
project area would be temporary behavioral avoidance of the area. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the short
timeframe for the wharf construction project. However, adverse impacts
may occur to a few species of rockfish and salmon which may still be
present in the project area despite operating in a reduced work window
in an attempt to avoid important fish spawning time periods. Impacts to
these species could result from potential impacts to their eggs and
larvae.
Pile Driving Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in the Hood Canal. Avoidance by
potential prey (i.e., fish) of the immediate area due to the temporary
loss of this foraging habitat is also possible. The duration of fish
avoidance of this area after pile driving stops is unknown, but a rapid
return to normal recruitment, distribution and behavior is anticipated.
Any behavioral avoidance by fish of the disturbed area would still
leave significantly large areas of fish and marine mammal foraging
habitat in the Hood Canal and nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Thus, any impacts to marine mammal
habitat are not expected to cause significant or long-term consequences
for individual marine mammals or their populations.
Proposed Mitigation
In order to issue an IHA under Section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to such
activity, and other means of effecting the least practicable impact on
such species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses.
Measurements from similar pile driving events were coupled with
practical spreading loss to estimate zones of influence (ZOI; see
``Estimated Take by Incidental Harassment''). These values were then
refined based on in situ measurements performed during the TPP, for
similar pile driving activity and within the EHW-2 project footprint,
to develop mitigation measures for EHW-2 pile driving activities. The
ZOIs effectively represent the mitigation zone that would be
established around each pile to prevent Level A harassment to marine
mammals, while providing estimates of the areas within which Level B
harassment might occur. While the ZOIs vary between the different
diameter piles and types of installation methods, the Navy is proposing
to establish mitigation zones for the maximum ZOI for all pile driving
conducted in support of the wharf
[[Page 32841]]
construction project. In addition to the measures described later in
this section, the Navy would employ the following standard mitigation
measures:
(a) Conduct briefings between construction supervisors and crews,
marine mammal monitoring team, and Navy staff prior to the start of all
pile driving activity, and when new personnel join the work, in order
to explain responsibilities, communication procedures, marine mammal
monitoring protocol, and operational procedures.
(b) For in-water heavy machinery work other than pile driving
(using, e.g., standard barges, tug boats, barge-mounted excavators, or
clamshell equipment used to place or remove material), if a marine
mammal comes within 10 m, operations shall cease and vessels shall
reduce speed to the minimum level required to maintain steerage and
safe working conditions. This type of work could include the following
activities: (1) Movement of the barge to the pile location; (2)
positioning of the pile on the substrate via a crane (i.e., stabbing
the pile); (3) removal of the pile from the water column/substrate via
a crane (i.e., deadpull); or (4) the placement of sound attenuation
devices around the piles. For these activities, monitoring would take
place from 15 minutes prior to initiation until the action is complete.
Monitoring and Shutdown for Pile Driving
The following measures would apply to the Navy's mitigation through
shutdown and disturbance zones:
Shutdown Zone--For all pile driving activities, the Navy will
establish a shutdown zone intended to contain the area in which SPLs
equal or exceed the 180/190 dB rms acoustic injury criteria. The
purpose of a shutdown zone is to define an area within which shutdown
of activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area), thus preventing
injury of marine mammals. Modeled distances for shutdown zones are
shown in Table 8. However, during impact pile driving, the Navy would
implement a minimum shutdown zone of 85 m radius for cetaceans and 20 m
radius for pinnipeds around all pile driving activity. The modeled
injury threshold distances are approximately 22 m and 5 m,
respectively, but the distances are increased based on in-situ recorded
sound pressure levels during the TPP. During vibratory driving, the
shutdown zone would be 10 m distance from the source for all animals.
These precautionary measures are intended to further reduce any
possibility of acoustic injury, as well as to account for any undue
reduction in the modeled zones stemming from the assumption of 10 dB
attenuation from use of a bubble curtain (see discussion later in this
section).
Disturbance Zone--Disturbance zones are the areas in which SPLs
equal or exceed 160 and 120 dB rms (for pulsed and non-pulsed
continuous sound, respectively). Disturbance zones provide utility for
monitoring conducted for mitigation purposes (i.e., shutdown zone
monitoring) by establishing monitoring protocols for areas adjacent to
the shutdown zones. Monitoring of disturbance zones enables observers
to be aware of and communicate the presence of marine mammals in the
project area but outside the shutdown zone and thus prepare for
potential shutdowns of activity. However, the primary purpose of
disturbance zone monitoring is for documenting incidents of Level B
harassment; disturbance zone monitoring is discussed in greater detail
later (see ``Proposed Monitoring and Reporting''). Nominal radial
distances for disturbance zones are shown in Table 8. Given the size of
the disturbance zone for vibratory pile driving, it is impossible to
guarantee that all animals would be observed or to make comprehensive
observations of fine-scale behavioral reactions to sound, and only a
portion of the zone (e.g., what may be reasonably observed by visual
observers stationed within the water front restricted area [WRA]) will
be monitored.
In order to document observed incidents of harassment, monitors
record all marine mammal observations, regardless of location. The
observer's location, as well as the location of the pile being driven,
is known from a GPS. The location of the animal is estimated as a
distance from the observer, which is then compared to the location from
the pile. The received level may be estimated on the basis of past or
subsequent acoustic monitoring. It may then be determined whether the
animal was exposed to sound levels constituting incidental harassment
in post-processing of observational data, and a precise accounting of
observed incidents of harassment created. Therefore, although the
predicted distances to behavioral harassment thresholds are useful for
estimating harassment for purposes of authorizing levels of incidental
take, actual take may be determined in part through the use of
empirical data. That information may then be used to extrapolate
observed takes to reach an approximate understanding of actual total
takes.
Monitoring Protocols--Monitoring would be conducted before, during,
and after pile driving activities. In addition, observers shall record
all incidents of marine mammal occurrence, regardless of distance from
activity, and shall document any behavioral reactions in concert with
distance from piles being driven. Observations made outside the
shutdown zone will not result in shutdown; that pile segment would be
completed without cessation, unless the animal approaches or enters the
shutdown zone, at which point all pile driving activities would be
halted. Monitoring will take place from fifteen minutes prior to
initiation through thirty minutes post-completion of pile driving
activities. Pile driving activities include the time to remove a single
pile or series of piles, as long as the time elapsed between uses of
the pile driving equipment is no more than thirty minutes. Please see
the Marine Mammal Monitoring Plan (available at www.nmfs.noaa.gov/pr/permits/incidental.htm), developed by the Navy with our approval, for
full details of the monitoring protocols.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Qualified observers
are trained biologists, with the following minimum qualifications:
Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
Advanced education in biological science or related field
(undergraduate degree or higher required);
Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and
[[Page 32842]]
times when in-water construction activities were suspended to avoid
potential incidental injury from construction sound of marine mammals
observed within a defined shutdown zone; and marine mammal behavior;
and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
(2) Prior to the start of pile driving activity, the shutdown zone
will be monitored for fifteen minutes to ensure that it is clear of
marine mammals. Pile driving will only commence once observers have
declared the shutdown zone clear of marine mammals; animals will be
allowed to remain in the shutdown zone (i.e., must leave of their own
volition) and their behavior will be monitored and documented. The
shutdown zone may only be declared clear, and pile driving started,
when the entire shutdown zone is visible (i.e., when not obscured by
dark, rain, fog, etc.). In addition, if such conditions should arise
during impact pile driving that is already underway, the activity would
be halted.
(3) If a marine mammal approaches or enters the shutdown zone
during the course of pile driving operations, activity will be halted
and delayed until either the animal has voluntarily left and been
visually confirmed beyond the shutdown zone or fifteen minutes have
passed without re-detection of the animal. Monitoring will be conducted
throughout the time required to drive a pile.
Sound Attenuation Devices
Sound levels can be greatly reduced during impact pile driving
using sound attenuation devices. There are several types of sound
attenuation devices including bubble curtains, cofferdams, and
isolation casings (also called temporary noise attenuation piles
[TNAP]), and cushion blocks. The Navy proposes to use bubble curtains,
which create a column of air bubbles rising around a pile from the
substrate to the water surface. The air bubbles absorb and scatter
sound waves emanating from the pile, thereby reducing the sound energy.
Bubble curtains may be confined or unconfined. An unconfined bubble
curtain may consist of a ring seated on the substrate and emitting air
bubbles from the bottom. An unconfined bubble curtain may also consist
of a stacked system, that is, a series of multiple rings placed at the
bottom and at various elevations around the pile. Stacked systems may
be more effective than non-stacked systems in areas with high current
and deep water (Oestman et al., 2009).
A confined bubble curtain contains the air bubbles within a
flexible or rigid sleeve made from plastic, cloth, or pipe. Confined
bubble curtains generally offer higher attenuation levels than
unconfined curtains because they may physically block sound waves and
they prevent air bubbles from migrating away from the pile. For this
reason, the confined bubble curtain is commonly used in areas with high
current velocity (Oestman et al., 2009).
Both environmental conditions and the characteristics of the sound
attenuation device may influence the effectiveness of the device.
According to Oestman et al. (2009):
In general, confined bubble curtains attain better sound
attenuation levels in areas of high current than unconfined bubble
curtains. If an unconfined device is used, high current velocity may
sweep bubbles away from the pile, resulting in reduced levels of sound
attenuation.
Softer substrates may allow for a better seal for the
device, preventing leakage of air bubbles and escape of sound waves.
This increases the effectiveness of the device. Softer substrates also
provide additional attenuation of sound traveling through the
substrate.
Flat bottom topography provides a better seal, enhancing
effectiveness of the sound attenuation device, whereas sloped or
undulating terrain reduces or eliminates its effectiveness.
Air bubbles must be close to the pile; otherwise, sound
may propagate into the water, reducing the effectiveness of the device.
Harder substrates may transmit ground-borne sound and
propagate it into the water column.
The literature presents a wide array of observed attenuation
results for bubble curtains (e.g., Oestman et al., 2009; Coleman, 2011;
see Table 6-5 of the Navy's application). The variability in
attenuation levels is due to variation in design, as well as
differences in site conditions and difficulty in properly installing
and operating in-water attenuation devices. As a general rule,
reductions of greater than 10 dB cannot be reliably predicted. The TPP
reported a range of measured values for realized attenuation mostly
within 6 to 12 dB (Illingworth & Rodkin, 2012). For 36-in piles the
average peak and rms reduction with use of the bubble curtain was 8 dB,
where the averages of all bubble-on and bubble-off data were compared.
For 48-in piles, the average SPL reduction with use of a bubble curtain
was 6 dB for average peak values and 5 dB for rms values. See Tables 6-
6 and 6-7 of the Navy's application.
To avoid loss of attenuation from design and implementation errors,
the Navy has required specific bubble curtain design specifications,
including testing requirements for air pressure and flow prior to
initial impact hammer use, and a requirement for placement on the
substrate. We considered TPP measurements (approximately 7 dB overall)
and other monitored projects (typically at least 8 dB realized
attenuation), and consider 8 dB as potentially the best estimate of
average SPL (rms) reduction, assuming appropriate deployment and no
problems with the equipment. In looking at other monitored projects
prior to completion of the TPP, the Navy determined with our
concurrence that an assumption of 10 dB realized attenuation was
realistic. Therefore, a 10 dB reduction was used in the Navy's analysis
of pile driving noise in the initial environmental analyses for the
EHW-2 project. The Navy's analysis is retained here. While
acknowledging that empirical evidence from the TPP indicates that the
10 dB target has not been consistently achieved, we did not require the
Navy to revisit their acoustic modeling because (1) shutdown and
disturbance zones for the second and third construction years are based
on in situ measurements rather than the original modeling that assumed
10 dB attenuation from a bubble curtain and (2) take estimates are not
affected because they are based on a combined modeled sound field
(i.e., concurrent operation of impact and vibratory drivers) rather
than there being separate take estimates for impact and vibratory pile
driving.
Bubble curtains shall be used during all impact pile driving. The
device will distribute air bubbles around 100 percent of the piling
perimeter for the full depth of the water column, and the lowest bubble
ring shall be in contact with the mudline for the full circumference of
the ring. Testing of the device by comparing attenuated and
unattenuated strikes is not possible because of requirements in place
to protect marbled murrelets (an ESA-listed bird species under the
jurisdiction of the USFWS). However, in order to avoid loss of
attenuation from design and implementation errors in the absence of
such testing, a performance test of the device shall be conducted prior
to initial use. The performance test shall confirm the calculated
pressures and flow rates at each manifold ring. In addition, the
contractor shall also train personnel in the proper balancing of air
flow to the bubblers and shall submit an
[[Page 32843]]
inspection/performance report to the Navy within 72 hours following the
performance test.
Timing Restrictions
In Hood Canal, designated timing restrictions exist for pile
driving activities to avoid in-water work when salmonids and other
spawning forage fish are likely to be present. The in-water work window
is July 16-February 15. Until September 23, impact pile driving will
only occur starting two hours after sunrise and ending two hours before
sunset due to marbled murrelet nesting season. After September 23, in-
water construction activities will occur during daylight hours (sunrise
to sunset).
Soft Start
The use of a soft-start procedure is believed to provide additional
protection to marine mammals by warning or providing a chance to leave
the area prior to the hammer operating at full capacity, and typically
involves a requirement to initiate sound from vibratory hammers for
fifteen seconds at reduced energy followed by a thirty-second waiting
period. This procedure is repeated two additional times.
However, implementation of soft start for vibratory pile driving
during previous pile driving work for the EHW-2 project at NBKB has led
to equipment failure and serious human safety concerns. Project staff
have reported that, during power down from the soft start, the energy
from the hammer is transferred to the crane boom and block via the load
fall cables and rigging resulting in unexpected damage to both the
crane block and crane boom. This differs from what occurs when the
hammer is powered down after a pile is driven to refusal in that the
rigging and load fall cables are able to be slacked prior to powering
down the hammer, and the vibrations are transferred into the substrate
via the pile rather than into the equipment via the rigging. One
dangerous incident of equipment failure has already occurred, with a
portion of the equipment shearing from the crane and falling to the
deck. Subsequently, the crane manufacturer has inspected the crane
booms and discovered structural fatigue in the boom lacing and main
structural components, which will ultimately result in a collapse of
the crane boom. All cranes were new at the beginning of the job. In
addition, the vibratory hammer manufacturer has attempted to install
dampers to mitigate the problem, without success.
It is the Navy's contention that this situation is unique to the
EHW-2 project, in comparison with other common marine construction
projects requiring pile driving. The design specifications of the
wharf, which require relatively large-diameter piles to be driven to
embedment in relatively deep water through stiff glacial soil, mean
that relatively greater driving energy, and therefore a larger hammer,
is required for successful embedment. The Marine Mammal Commission
previously recommended that we require the Navy to consult with the
Washington State Department of Transportation and/or the California
Department of Transportation to determine whether soft start procedures
can be used safely with the vibratory hammers that the Navy plans to
use. We agreed with that recommendation and are still working to
facilitate such a consultation in order to determine whether the
potentially significant human safety issue is inherent to
implementation of the measure or is due to operator error. However, our
interest in examining this issue is related to our need to understand
the conditions under which vibratory soft start may be advisable from
an engineering perspective for future projects.
For this proposed IHA and for the remainder of the EHW-2 project,
as a result of this potential risk to human safety, we have determined
vibratory soft start to not currently be practicable. Therefore, the
measure will not be required. We have further determined this measure
unnecessary to providing the means of effecting the least practicable
impact on marine mammals and their habitat.
For impact driving, soft start will be required, and contractors
will provide an initial set of strikes from the impact hammer at
reduced energy, followed by a thirty-second waiting period, then two
subsequent reduced energy strike sets. The reduced energy of an
individual hammer cannot be quantified because of variation in
individual drivers. The actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes.'' Soft start for impact driving will be required at
the beginning of each day's pile driving work and at any time following
a cessation of impact pile driving of thirty minutes or longer.
We have carefully evaluated the Navy's proposed mitigation measures
and considered their effectiveness in past implementation to
preliminarily determine whether they are likely to effect 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: (1)
The manner in which, and the degree to which, the successful
implementation of the measure is expected to minimize adverse impacts
to marine mammals, (2) the proven or likely efficacy of the specific
measure to minimize adverse impacts as planned; and (3) the
practicability of the measure for applicant implementation.
Any mitigation measure(s) we prescribe 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 number (total number or number at
biologically important time or location) of individual marine mammals
exposed to stimuli expected to result in incidental take (this goal may
contribute to 1, above, or to reducing takes by behavioral harassment
only).
(3) A reduction in the number (total number or number at
biologically important time or location) of times any individual marine
mammal would be exposed to stimuli expected to result in incidental
take (this goal may contribute to 1, above, or to reducing takes by
behavioral harassment only).
(4) A reduction in the intensity of exposure to stimuli expected to
result in incidental take (this goal may contribute to 1, above, or to
reducing the severity of behavioral harassment only).
(5) Avoidance or minimization of adverse effects to marine mammal
habitat, paying particular attention to the prey base, blockage or
limitation of passage to or from biologically important areas,
permanent destruction of habitat, or temporary 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 Navy's proposed measures, including
information from monitoring of the Navy's implementation of the
mitigation measures as prescribed under previous IHAs for this and
other projects in the Hood Canal, we have preliminarily determined that
the proposed mitigation measures provide the means of effecting the
least practicable impact on marine mammal species or stocks and their
[[Page 32844]]
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth ``requirements pertaining to
the monitoring and reporting of such taking''. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
incidental take authorizations must include the suggested means of
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species and of the level of taking or
impacts on populations of marine mammals that are expected to be
present in the proposed action area.
Any monitoring requirement we prescribe should accomplish one or
more of the following general goals:
1. An increase in the probability of detecting marine mammals, both
within defined zones of effect (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 stimuli that we associate with specific adverse
effects, such as behavioral harassment or hearing threshold shifts;
3. An increase in our understanding of how marine mammals respond
to stimuli expected to result in incidental take and how anticipated
adverse effects on individuals may impact the population, stock, or
species (specifically through effects on annual rates of recruitment or
survival) through any of the following methods:
Behavioral observations in the presence of stimuli
compared to observations in the absence of stimuli (need to be able to
accurately predict pertinent information, e.g., received level,
distance from source);
Physiological measurements in the presence of stimuli
compared to observations in the absence of stimuli (need to be able to
accurately predict pertinent information, e.g., received level,
distance from source);
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; or
5. An increase in our understanding of the effectiveness of certain
mitigation and monitoring measures.
The Navy submitted a marine mammal monitoring plan as part of the
IHA application for year two of this project. It will be applied to
year three of this project and can be found on the Internet at
www.nmfs.noaa.gov/pr/permits/incidental.htm. The plan has been
successfully implemented by the Navy under the previous IHA and may be
modified or supplemented based on comments or new information received
from the public during the public comment period.
Visual Marine Mammal Observations
The Navy will collect sighting data and behavioral responses to
construction for marine mammal species observed in the region of
activity during the period of activity. All observers will be trained
in marine mammal identification and behaviors and are required to have
no other construction-related tasks while conducting monitoring. The
Navy will monitor the shutdown zone and disturbance zone before,
during, and after pile driving, with observers located at the best
practicable vantage points. Based on our requirements, the Marine
Mammal Monitoring Plan would implement the following procedures for
pile driving:
MMOs would be located at the best vantage point(s) in
order to properly see the entire shutdown zone and as much of the
disturbance zone as possible.
During all observation periods, observers will use
binoculars and the naked eye to search continuously for marine mammals.
If the shutdown zones are obscured by fog or poor lighting
conditions, pile driving at that location will not be initiated until
that zone is visible. Should such conditions arise while impact driving
is underway, the activity would be halted.
The shutdown and disturbance zones around the pile will be
monitored for the presence of marine mammals before, during, and after
any pile driving or removal activity.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. Monitoring biologists will
use their best professional judgment throughout implementation and seek
improvements to these methods when deemed appropriate. Any
modifications to protocol will be coordinated between NMFS and the
Navy.
Data Collection
We require that observers use approved data forms. Among other
pieces of information, the Navy will record detailed information about
any implementation of shutdowns, including the distance of animals to
the pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, the Navy will attempt to
distinguish between the number of individual animals taken and the
number of incidents of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel and distance from
pile driving activity;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report would be submitted within ninety calendar days of
the completion of the in-water work window. The report will include
marine mammal observations pre-activity, during-activity, and post-
activity during pile driving days, and will also provide descriptions
of any problems encountered in deploying sound attenuating devices, any
behavioral responses to construction activities by marine mammals and a
complete description of all mitigation shutdowns and the results of
those actions and an extrapolated total take estimate based on the
number of marine mammals observed during the course of construction. A
final report must be submitted within thirty days following resolution
of comments on the draft report.
Monitoring Results From Previously Authorized Activities
The Navy complied with the mitigation and monitoring required under
the previous authorizations for this project. Marine mammal monitoring
occurred before, during, and after each pile driving event. During the
course of these activities, the Navy did not exceed the take levels
authorized under the IHAs.
In accordance with the 2012 IHA, the Navy submitted a Year 1 Marine
Mammal Monitoring Report (2012-2013), covering the period of July 16
[[Page 32845]]
through February 15. Due to delays in beginning the project the first
day of monitored pile driving activity occurred on September 28, 2012,
and a total of 78 days of pile driving occurred between then and
February 14, 2013. That total included 56 days of vibratory driving
only, three days of only impact driving, and 19 days where both
vibratory and impact driving occurred, with a maximum concurrent
deployment of two vibratory drivers and one impact driver.
Monitoring was conducted in two areas: (1) Primary visual surveys
within the disturbance and shutdown zones in the WRA (approximately
500-m radius), (2) boat surveys outside the WRA but within the
disturbance zone. The latter occurred only during acoustic monitoring
accomplished at the outset of the work period, which required a small
vessel be deployed outside the WRA. Marine mammal observers were placed
on construction barges, the construction pier, and vessels located in
near-field (within the WRA) and far-field (outside the WRA) locations,
in accordance with the Marine Mammal Monitoring Plan.
Monitoring for the second year of construction was conducted
throughout the 2013-14 work window (i.e., mid-July to mid-February).
The monitoring was conducted in the same manner as the first year, but
was limited to within the WRA as no acoustic monitoring was conducted
during the second year. At the time of this writing, the Navy has
provided a draft of the Year 2 Marine Mammal Report and it is under
review. We have made the draft report available for public review and
comment prior to any final decision regarding this proposed
authorization.
Table 3 summarizes monitoring results from years one and two of the
EHW-2 project, including observations from all monitoring effort
(including while pile driving was not actively occurring) and records
of unique observations during active pile driving (seen in the far
right column). Primary surveys refer to observations by stationary and
vessel-based monitors within the WRA. Boat surveys refer to vessel-
based surveys conducted outside the WRA (Year 1 only). No Steller sea
lions have been observed within defined ZOIs during active pile
driving, and no killer whales have been observed during any project
monitoring at NBKB. For more detail, including full monitoring results
and analysis, please see the monitoring reports at www.nmfs.noaa.gov/pr/permits/incidental.htm.
Table 3--Summary Marine Mammal Monitoring Results, EHW-2 Years 1-2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total individuals
observed (active
Total number Total number Maximum group pile driving and
Activity \1\ Species groups observed individuals size within
observed disturbance zone
only)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Primary surveys, Y1......................... California sea lion........... 30 30 1 4
Harbor seal................... 939 984 4 214
Boat surveys, Y1............................ California sea lion........... 21 126 20 22
Steller sea lion.............. 3 3 1 0
Harbor seal................... 73 76 2 22
Harbor porpoise............... 10 57 10 36
Primary surveys, Y2......................... California sea lion........... 77 83 3 10
Harbor seal................... 3,046 3,229 5 713
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Total observation effort during active pile driving: Year 1--530 hours, 50 minutes on eighty construction days; Year 2--1,247 hours, 27 minutes on
162 construction days.
Acoustic Monitoring--During the first year of construction for EHW-
2, the Navy conducted acoustic monitoring as required under the IHA.
During year one, 24- to 36-in diameter piles were primarily driven, by
vibratory and impact driving. Only one 48-in pile was driven, so no
data are provided for that pile size. All piles were steel pipe piles.
Primary objectives for the acoustic monitoring were to characterize
underwater and airborne source levels for each pile size and hammer
type and to verify distances to relevant threshold levels by
characterizing site-specific transmission loss. Measurements of impact
driving for 24-in piles showed a high degree of variation (SD = 24.1)
because many of these piles were driven either on land or in extremely
shallow water, while others were driven in deeper water more
characteristic of typical driving conditions for EHW-2. Select results
are reproduced here (Tables 4-5); the interested reader may find the
entire report posted at www.nmfs.noaa.gov/pr/permits/incidental.htm.
Acoustic monitoring was also conducted during the TPP and during year
one of the EHW-1 project. Those reports may be found at the same
address. Acoustic measurements from NBKB are discussed further below in
``Estimated Take by Incidental Harassment.''
Table 4--Acoustic Monitoring Results From 2012-13 Activities at EHW-2 (Year 1)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Underwater Airborne
Pile size (in) Hammer type \1\ n \2\ ----------------------------------------------------------------
RL \3\ SD \4\ TL \5\ RL \6\ SD
--------------------------------------------------------------------------------------------------------------------------------------------------------
24......................................... Impact....................... 41 179 24.1 18.6 103 1.0
36......................................... Impact....................... 26 188 5.0 14.9 102 2.2
24......................................... Vibratory.................... 71 163 8.3 15.3 95 3.7
36......................................... Vibratory.................... 113 169 4.3 16.8 103 3.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ All data for impact driving include use of bubble curtain; \2\ n = sample size, or number of measured pile driving events; \3\ Received level at 10
m, presented in dB rms; \4\ Standard deviation; \5\ Transmission loss (log10); \6\ Received level at 15 m, presented in dB rms (Z-weighted Leq).
[[Page 32846]]
For vibratory driving, measured source levels were below the 180-dB
threshold. Calculation of average distances to the 120-dB threshold was
complicated by variability in propagation of sound at greater
distances, variability in measured sounds from event to event, and the
difficulty of making measurements, given noise from wind and wave
action, in the far field (Table 5). Also, as observed during previous
monitoring events at NBKB, measured levels in shallower water at the
far side of Hood Canal are sometimes louder than measurements made
closer to the source in the deeper open channel. These events are
unexplained. Estimated radial distances to the 120-dB threshold were
highly variable, but typically less than the maximum distance as
constrained by land (i.e., 13,800 m; Table 9). The topography of Hood
Canal realistically constrains distances to 7,000 m to the south of the
project area.
Table 5--Measured Values From TPP and EHW-2 Acoustic Monitoring, Including Distances to Relevant Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Measured distances to relevant thresholds (rms)
Project Type Source level (dB Transmission -------------------------------------------------------------------
rms) loss 120-dB \1\ 160-dB 180-dB 190-dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
TPP........................... Impact; 36-in.... 181 (avg)/183 16.4 n/a.............. 425 m.......... 35 m.......... <10 m.
(max).
TPP........................... Impact; 48-in.... 187 (avg)/188 13.4 n/a.............. 1,300 m........ 60 m.......... 15 m.
(max).
TPP........................... Vibratory; 36- to ................. .............. 1,200-8,000+ m... n/a............ n/a........... n/a.
48-in.
EHW-2 (Y1).................... Impact; 36-in.... 188 dB (avg)/191 14.9 n/a.............. 670 m.......... 45 m.......... 12 m.
dB (max).
EHW-2 (Y1).................... Vibratory; 36-in. ................. .............. 4,400 m (avg)/ n/a............ n/a........... n/a.
10,250 m (max).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Distances to 120-dB threshold are estimated from measured source level and transmission loss values. The distances themselves are not measured.
Sound levels during soft starts were typically lower than those
levels at the initiation and completion of continuous vibratory
driving. However, levels during continuous driving varied considerably
and were at times lower than those produced during the soft starts. It
is difficult to assign a level that describes how much lower the soft
start sound levels were than continuous levels. Similarly inconclusive
results were seen from monitoring associated with the TPP.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here,
section 3(18) of the MMPA defines ``harassment'' as any act of pursuit,
torment, or annoyance which has the potential to injure a marine mammal
or marine mammal stock in the wild; or 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. The former is
termed Level A harassment and the latter is termed Level B harassment.
All anticipated takes would be by Level B harassment resulting from
vibratory and impact pile driving and involving temporary changes in
behavior. The proposed mitigation and monitoring measures are expected
to minimize the possibility of injurious or lethal takes such that take
by Level A harassment, serious injury, or mortality is considered
discountable. However, it is unlikely that injurious or lethal takes
would occur even in the absence of the planned mitigation and
monitoring measures.
If a marine mammal responds to a stimulus by changing its behavior
(e.g., through relatively minor changes in locomotion direction/speed
or vocalization behavior), the response may or may not constitute
taking at the individual level, and is unlikely to affect the stock or
the species as a whole. However, if a sound source displaces marine
mammals from an important feeding or breeding area for a prolonged
period, impacts on animals or on the stock or species could potentially
be significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007). Given
the many uncertainties in predicting the quantity and types of impacts
of sound on marine mammals, it is common practice to estimate how many
animals are likely to be present within a particular distance of a
given activity, or exposed to a particular level of sound.
This practice potentially overestimates the numbers of marine
mammals taken. For example, during the past fifteen years, killer
whales have been observed within the project area twice. On the basis
of that information, an estimated amount of potential takes for killer
whales is presented here. However, while a pod of killer whales could
potentially visit again during the project timeframe, and thus be
taken, it is more likely that they will not. Although incidental take
of killer whales and Dall's porpoises was authorized for 2011-12 and
2012-13 activities at NBKB on the basis of past observations of these
species, no such takes were recorded and no individuals of these
species were observed. Similarly, estimated actual take levels
(observed takes extrapolated to the remainder of unobserved but
ensonified area) were significantly less than authorized levels of take
for the remaining species. In addition, it is often difficult to
distinguish between the individuals harassed and incidences of
harassment. In particular, for stationary activities, it is more likely
that some smaller number of individuals may accrue a number of
incidences of harassment per individual than for each incidence to
accrue to a new individual, especially if those individuals display
some degree of residency or site fidelity and the impetus to use the
site (e.g., because of foraging opportunities) is stronger than the
deterrence presented by the harassing activity.
The project area is not believed to be particularly important
habitat for marine mammals, nor is it considered an area frequented by
marine mammals, although harbor seals are year-round residents of Hood
Canal and sea lions are known to haul-out on submarines and other man-
made objects at the NBKB waterfront (although typically at a distance
of a mile or greater from the project site). Therefore, behavioral
disturbances that could result from anthropogenic sound associated with
these activities are expected to affect only a relatively small number
of individual marine mammals, although those effects could be recurring
over the
[[Page 32847]]
life of the project if the same individuals remain in the project
vicinity.
The Navy has requested authorization for the incidental taking of
small numbers of Steller sea lions, California sea lions, harbor seals,
transient killer whales, and harbor porpoises in the Hood Canal that
may result from pile driving during construction activities associated
with the wharf construction project described previously in this
document. In order to estimate the potential incidents of take that may
occur incidental to the specified activity, we must first estimate the
extent of the sound field that may be produced by the activity and then
consider in combination with information about marine mammal density or
abundance in the project area. We first provide information on
applicable sound thresholds for determining effects to marine mammals
before describing the information used in estimating the sound fields,
the available marine mammal density or abundance information, and the
method of estimating potential incidences of take.
Sound Thresholds
We use generic sound exposure thresholds to determine when an
activity that produces sound might result in impacts to a marine mammal
such that a take by harassment might occur. To date, no studies have
been conducted that explicitly examine impacts to marine mammals from
pile driving sounds or from which empirical sound thresholds have been
established. These thresholds should be considered guidelines for
estimating when harassment may occur (i.e., when an animal is exposed
to levels equal to or exceeding the relevant criterion) in specific
contexts; however, useful contextual information that may inform our
assessment of effects is typically lacking and we consider these
thresholds as step functions. NMFS is currently revising these acoustic
guidelines; for more information on that process, please visit
www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. Vibratory pile driving
produces continuous noise and impact pile driving produces impulsive
noise.
Table 6--Current Acoustic Exposure Criteria
------------------------------------------------------------------------
Criterion Definition Threshold
------------------------------------------------------------------------
Level A harassment Injury (PTS--any 180 dB (cetaceans)/
(underwater). level above that 190 dB (pinnipeds)
which is known to (rms).
cause TTS).
Level B harassment Behavioral 160 dB (impulsive
(underwater). disruption. source)/120 dB
(continuous source)
(rms).
Level B harassment Behavioral 90 dB (harbor seals)/
(airborne)*. disruption. 100 dB (other
pinnipeds)
(unweighted).
------------------------------------------------------------------------
* NMFS has not established any formal criteria for harassment resulting
from exposure to airborne sound. However, these thresholds represent
the best available information regarding the effects of pinniped
exposure to such sound and NMFS' practice is to associate exposure at
these levels with Level B harassment.
Distance to Sound Thresholds
Underwater Sound Propagation Formula--Pile driving generates
underwater noise that can potentially result in disturbance to marine
mammals in the project area. Transmission loss (TL) is the decrease in
acoustic intensity as an acoustic pressure wave propagates out from a
source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and
bottom composition and topography. The general formula for underwater
TL is:
TL = B * log10(R1/R2),
where
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which is
assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of fifteen is often used under conditions,
such as Hood Canal, where water increases with depth as the receiver
moves away from the shoreline, resulting in an expected propagation
environment that would lie between spherical and cylindrical spreading
loss conditions. Practical spreading loss (4.5 dB reduction in sound
level for each doubling of distance) is assumed here.
Underwater Sound--The intensity of pile driving sounds is greatly
influenced by factors such as the type of piles, hammers, and the
physical environment in which the activity takes place. A large
quantity of literature regarding SPLs recorded from pile driving
projects is available for consideration. In order to determine
reasonable SPLs and their associated effects on marine mammals that are
likely to result from pile driving at NBKB, studies with similar
properties to the specified activity were evaluated, including
measurements conducted for driving of steel piles at NBKB as part of
the TPP (Illingworth & Rodkin, 2012). During the TPP, SPLs from driving
of 24-, 36-, and 48-in piles by impact and vibratory hammers were
measured. Overall, studies which met the following parameters were
considered: (1) Pile size and materials: Steel pipe piles (30- to 72-in
diameter); (2) Hammer machinery: Vibratory and impact hammer; and (3)
Physical environment: shallow depth (less than 30 m).
[[Page 32848]]
Table 7--Underwater SPLs From Monitored Construction Activities Using Impact Hammers
----------------------------------------------------------------------------------------------------------------
Water depth
Project and location Pile size and type (m) Measured SPLs
----------------------------------------------------------------------------------------------------------------
Eagle Harbor Maintenance Facility, 30-in steel pipe.... 10 192 dB (rms) at 10 m.
WA \1\.
Friday Harbor Ferry Terminal, WA 30-in steel pipe.... 10 196 dB (rms) at 10 m.
\2\.
Humboldt Bay Bridges, CA \3\...... 36-in CISS pipe..... 10 193 dB (rms) at 10 m.
Mukilteo Test Piles, WA \4\....... 36-in steel pipe.... 7.3 195 dB (rms) at 10 m.
Anacortes Ferry, WA \5\........... 36-in steel pipe.... 12.8 199 dB (rms) at 10 m.
Test Pile Program, NBKB \6\....... 36-in steel pipe.... 13.7-26.8 196 dB (rms) at 10 m.
EHW-2, Year 1, NBKB \7\........... 36-in steel pipe.... 13.7-26.8 194 dB (rms) at 10 m.\9\
Carderock Pier, NBKB \8\.......... 42-in steel pipe.... 14.6-21.3 195 dB (rms) at 10 m.\10\
Russian River, CA \3\............. 48-in CISS pipe..... 2 195 dB (rms) at 10 m.
Test Pile Program, NBKB \6\....... 48-in steel pipe.... 26.2-28 194 dB (rms) at 10 m.
California \3\.................... 60-in CISS pipe..... 10 195 dB (rms) at 10 m.\11\
Richmond-San Rafael Bridge, CA \3\ 66-in cast-in- 4 195 dB (rms) at 10 m.
drilled-hole steel
pipe.
----------------------------------------------------------------------------------------------------------------
Sources: \1\ MacGillivray and Racca, 2005; \2\ Laughlin, 2005; \3\ Caltrans, 2012; \4\ MacGillivray, 2007; \5\
Sexton, 2007; \6\ Illingworth & Rodkin, 2012; \7\ Illingworth & Rodkin, 2013; \8\ DoN, 2009.
\9\ Bubble curtain in place for all measurements.
\10\ Source level at 10 m estimated based on measurements at distances of 48-387 m.
\11\ Specific location/project unknown. Summary value possibly comprising multiple events rather than a single
event.
The tables presented here detail representative pile driving SPLs
that have been recorded from similar construction activities in recent
years. Due to the similarity of these actions and the Navy's proposed
action, these values represent reasonable SPLs which could be
anticipated, and which were used in the acoustic modeling and analysis.
Table 7 displays SPLs measured during pile installation using an impact
hammer and Table 8 displays SPLs measured during pile installation
using a vibratory hammer. For impact driving, a source value of 195 dB
rms at 10 m was the average value reported from the listed studies, and
is consistent with measurements from the TPP and Carderock Pier pile
driving projects at NBKB, which had similar pile materials (48- and 42-
inch hollow steel piles, respectively), water depth, and substrate type
as the EHW-2 project site. For vibratory pile driving, the Navy
selected the most conservative value (72-in piles; 180 dB rms at 10 m)
available when initially assessing EHW-2 project impacts, prior to the
first year of the project. Since then, data have become available that
indicate, on average, a lower source level for vibratory pile driving
(e.g., 172 dB rms for 48-in steel piles). However, for consistency we
have maintained the initial conservative assumption regarding source
level for vibratory driving.
Table 8--Underwater SPLs From Monitored Construction Activities Using Vibratory Hammers
----------------------------------------------------------------------------------------------------------------
Pile size and
Project and location type Water depth Measured SPLs
----------------------------------------------------------------------------------------------------------------
Vashon Terminal, WA \1\....... 30-in steel pipe. 6 m.............. 165 dB (rms) at 11 m.
Keystone Terminal, WA \2\..... 30-in steel pipe. 8 m.............. 165 dB (rms) at 10 m.
Edmonds Ferry Terminal, WA \3\ 36-in steel pipe. 5.8 m............ 162-163 dB (rms) at 10 m.
Anacortes Ferry Terminal, WA 36-in steel pipe. 12.7 m........... 168-170 dB (rms) at 10 m.
\4\.
California \5\................ 36-in steel pipe. 5 m.............. 170 dB/175 dB (rms) at 10 m.\8\
Test Pile Program, NBKB \6\... 36-in steel pipe. 13.7-26.8 m...... 154-169 dB (rms) at 10 m.
EHW-2, Year 1, NBKB \7\....... 36-in steel pipe. Avg of mid- and 169 dB (rms) at 10 m.
deep-depth.
Test Pile Program, NBKB \6\... 48-in steel pipe. 13.7-26.8 m...... 172 dB (rms) at 10 m.
California \3\................ 72-in steel pipe. 5 m.............. 170 dB/180 dB (rms) at 10 m.\8\
----------------------------------------------------------------------------------------------------------------
Sources: \1\ Laughlin, 2010a; \2\ Laughlin, 2010b; \3\ Loughlin, 2011; \4\ Loughlin, 2012; \5\ Caltrans, 2012;
\6\ Illingworth & Rodkin, 2012; \7\ Illingworth & Rodkin, 2013.
\8\ Specific location/project unknown. Summary value possibly comprising multiple events rather than a single
event. Average and maximum values presented.
All calculated distances to and the total area encompassed by the
marine mammal sound thresholds are provided in Table 9. The Navy used
source values of 185 dB rms for impact driving (the mean SPL of the
values presented in Table 7, less 10 dB of sound attenuation from use
of a bubble curtain) and 180 dB rms for vibratory driving (the worst-
case value from Table 8). Under the worst-case construction scenario,
up to three vibratory drivers would operate simultaneously with one
impact driver. Although radial distance and area associated with the
zone ensonified to 160 dB (the behavioral harassment threshold for
pulsed sounds, such as those produced by impact driving) are presented
in Table 9, this zone would be subsumed by the 120-dB zone produced by
vibratory driving. Thus, behavioral harassment of marine mammals
associated with impact driving is not considered further here. Since
the 160-dB threshold and the 120-dB threshold both indicate behavioral
harassment, pile driving effects in the two zones are equivalent.
Although not considered as a likely construction scenario, if only the
impact driver was operated on a given day incidental take on that day
would likely be lower because the area ensonified to levels producing
Level B harassment would be smaller (although actual take would be
determined by the numbers of marine mammals in the area on that day).
The use of multiple vibratory rigs at the same time would result in a
small additive effect with regard to produced SPLs; however, because
the sound field produced by vibratory driving would be truncated by
land in the Hood Canal, no increase in actual sound field produced
would occur. There would be no overlap in the 190/180-dB sound fields
produced by rigs operating simultaneously.
[[Page 32849]]
Table 9--Calculated Distance(s) to and Area Encompassed by Underwater
Marine Mammal Sound Thresholds During Pile Installation
------------------------------------------------------------------------
Distance \1\
Threshold (m) Area (km\2\)
------------------------------------------------------------------------
Impact driving, pinniped injury (190 dB) 4.9. 0.0001
Impact driving, cetacean injury (180 dB) 22. 0.002
Impact driving, disturbance (160 dB)\2\. 724. 1.65
Vibratory driving, pinniped injury (190 2.1. < 0.0001
dB)....................................
Vibratory driving, cetacean injury (180 10. 0.0003
dB)....................................
Vibratory driving, disturbance (120 13,800. 41.4
dB)\3\.................................
------------------------------------------------------------------------
\1\ SPLs used for calculations were: 185 dB for impact and 180 dB for
vibratory driving.
\2\ Area of 160-dB zone presented for reference. Estimated incidental
take calculated on basis of larger 120-dB zone.
\3\ Hood Canal average width at site is 2.4 km, and is fetch limited
from N to S at 20.3 km. Calculated range (over 222 km) is greater than
actual sound propagation through Hood Canal due to intervening land
masses. The greatest line-of-sight distance from pile driving
locations unimpeded by land masses is 13.8 km (i.e., the maximum
possible distance for propagation of sound).
Hood Canal does not represent open water, or free field,
conditions. Therefore, sounds would attenuate as they encounter land
masses or bends in the canal. As a result, the calculated distance and
areas of impact for the 120-dB threshold cannot actually be attained at
the project area. See Figure 6-1 of the Navy's application for a
depiction of the size of areas in which each underwater sound threshold
is predicted to occur at the project area due to pile driving.
Airborne Sound--Pile driving can generate airborne sound that could
potentially result in disturbance to marine mammals (specifically,
pinnipeds) which are hauled out or at the water's surface. As a result,
the Navy analyzed the potential for pinnipeds hauled out or swimming at
the surface near NBKB to be exposed to airborne SPLs that could result
in Level B behavioral harassment. A spherical spreading loss model
(i.e., 6 dB reduction in sound level for each doubling of distance from
the source), in which there is a perfectly unobstructed (free-field)
environment not limited by depth or water surface, is appropriate for
use with airborne sound and was used to estimate the distance to the
airborne thresholds.
As was discussed for underwater sound from pile driving, the
intensity of pile driving sounds is greatly influenced by factors such
as the type of piles, hammers, and the physical environment in which
the activity takes place. In order to determine reasonable airborne
SPLs and their associated effects on marine mammals that are likely to
result from pile driving at NBKB, studies with similar properties to
the proposed action, as described previously, were evaluated. Table 10
details representative pile driving activities that have occurred in
recent years. Due to the similarity of these actions and the Navy's
proposed action, they represent reasonable SPLs which could be
anticipated. Measured values from the TPP and EHW-2 (Year 1) are
generally lower than those assumed for Navy's initial analysis for
impact driving and generally equivalent to what was assumed for
vibratory driving (see values for Northstar Island and Keystone Ferry
Terminal in Table 10; note that these equate to approximately 118 dB
and 96 dB when standardized to 15 m). However, these values were
retained for impact assessment because they either result in a more
conservative distance to threshold (impact driving) or are equivalent
(vibratory driving). Please see Illingworth & Rodkin (2012, 2013) for
details of the TPP and EHW-2 measurements.
Table 10--Airborne SPLs From Similar Construction Activities
----------------------------------------------------------------------------------------------------------------
Pile size and
Project and location type Method Measured SPLs \5\
----------------------------------------------------------------------------------------------------------------
Northstar Island, AK \1\...... 42-in steel pipe. Impact........... 97 dB rms at 160 m.
TPP, NBKB \2\................. 36-in steel pipe. Impact........... 109 dB Lmax at 15 m.
TPP, NBKB \2\................. 48-in steel pipe. Impact........... 107 dB at 15 m.
EHW-2, Year 1, NBKB \3\....... 24-in steel pipe. Impact........... 111 dB Lmax at 15 m.
EHW-2, Year 1, NBKB \3\....... 36-in steel pipe. Impact........... 111 dB at 15 m.
EHW-2, Year 1, NBKB \3\....... 24-in steel pipe. Vibratory........ 95 dB Leq at 15 m.
Keystone Ferry Terminal, WA 30-in steel pipe. Vibratory........ 98 dB rms at 11 m.
\4\.
TPP, NBKB \2\................. 36-in steel pipe. Vibratory........ 93 dB Leq at 15 m.
EHW-2, Year 1, NBKB \3\....... 36-in steel pipe. Vibratory........ 103 Leq dB at 15 m.
TPP, NBKB \2\................. 48-in steel pipe. Vibratory........ 94 dB Leq at 15 m.
----------------------------------------------------------------------------------------------------------------
Sources: \1\ Blackwell et al., 2004; \2\ Illingworth & Rodkin, 2012; \3\ Illingworth & Rodkin, 2013; \4\
Laughlin, 2010b.
\5\ Lmax = maximum level; Leq = equivalent level.
[[Page 32850]]
Based on these values and the assumption of spherical spreading
loss, distances to relevant thresholds and associated areas of
ensonification under the multi-rig scenario (i.e., combined impact and
vibratory driving) are presented in Table 11. See Figure 6-2 of the
Navy's application for a depiction of the size of areas in which each
airborne sound threshold is predicted to occur at the project area due
to pile driving.
Table 11--Distances to Relevant Sound Thresholds and Areas of
Ensonification, Airborne Sound
------------------------------------------------------------------------
Distance to
threshold (m) and
associated area
Group Threshold of ensonification
(dB) (km\2\); combined
rig scenario
(worst-case)
------------------------------------------------------------------------
Harbor seals............................. 90 dB 361, 0.07
Sea lions................................ 100 dB 114, 0.005
------------------------------------------------------------------------
Marine Mammal Densities
The Navy has developed, with input from regional marine mammal
experts, estimates of marine mammal densities in Washington inland
waters for the Navy Marine Species Density Database (NMSDD). A
technical report (Hanser et al., 2014) describes methodologies and
available information used to derive these densities, which are
generally considered the best available information for Washington
inland waters, except where specific local abundance information is
available. Initial impact assessment for the EHW-2 project relied on
data available at the time the application was submitted, including
survey efforts conducted in the project area. Here, we rely on NMSDD
density information for the harbor seal, killer whale, and harbor
porpoise and use local abundance data for the California sea lion and
Steller sea lion. This approach is the same as that taken for
estimating take for Year 2 of the EHW-2 project, which represented a
departure from the approach taken for Year 1 of EHW-2 for certain
species. Please see Appendix A of the Navy's application for more
information on the NMSDD information.
For all species, the most appropriate information available was
used to estimate the number of potential incidences of take. For harbor
seals, this involved published literature describing harbor seal
research conducted in Washington and Oregon, including counts from Hood
Canal (Huber et al., 2001; Jeffries et al., 2003). Killer whales are
known from two periods of occurrence (2003 and 2005) and are not known
to preferentially use any specific portion of the Hood Canal.
Therefore, density was calculated as the maximum number of individuals
expected to be present at a given time (Houghton et al., in prep.),
divided by the area of Hood Canal. The best information available for
the remaining species in Hood Canal came from surveys conducted by the
Navy at the NBKB waterfront or in the vicinity of the project area.
Beginning in April 2008, Navy personnel have recorded sightings of
marine mammals occurring at known haul-outs along the NBKB waterfront,
including docked submarines or other structures associated with NBKB
docks and piers and the nearshore pontoons of the floating security
fence. Sightings of marine mammals within the waters adjoining these
locations were also recorded. Sightings were attempted whenever
possible during a typical work week (i.e., Monday through Friday), but
inclement weather, holidays, or security constraints often precluded
surveys. These sightings took place frequently, although without a
formal survey protocol. During the surveys, staff visited each of the
above-mentioned locations and recorded observations of marine mammals.
Surveys were conducted using binoculars and the naked eye from
shoreline locations or the piers/wharves themselves. Because these
surveys consist of opportunistic sighting data from shore-based
observers, largely of hauled-out animals, there is no associated survey
area appropriate for use in calculating a density from the abundance
data. Data were compiled for the period from April 2008 through
December 2013 for analysis here, and these data provide the basis for
take estimation for Steller and California sea lions. Other
information, including sightings data from other Navy survey efforts at
NBKB, is available for these two species, but these data provide the
most conservative (i.e., highest) local abundance estimates (and thus
the highest estimates of potential take). These data are also most
appropriate for these two species because they are attracted to the
NBKB waterfront due to the availability of suitable haul-out sites. The
cetaceans and (to a lesser extent) the harbor seal are not specifically
attracted to any attribute of the project area and are assumed to occur
uniformly throughout the project area.
In addition, vessel-based marine wildlife surveys were conducted
according to established survey protocols during July through September
2008 and November through May 2009-10 (Tannenbaum et al., 2009, 2011).
Eighteen complete surveys of the nearshore area resulted in
observations of four marine mammal species (harbor seal, California sea
lion, harbor porpoise, and Dall's porpoise). These surveys operated
along pre-determined transects parallel to the shoreline from the
nearshore out to approximately 550 m from shoreline, at a spacing of
100 yd, and covered the entire NBKB waterfront (approximately 3.9 km\2\
per survey) at a speed of 5 kn or less. Two observers recorded
sightings of marine mammals both in the water and hauled out, including
date, time, species, number of individuals, age (juvenile, adult),
behavior (swimming, diving, hauled out, avoidance dive), and haul-out
location. Positions of marine mammals were obtained by recording
distance and bearing to the animal with a rangefinder and compass,
noting the concurrent location of the boat with GPS, and, subsequently,
analyzing these data to produce coordinates of the locations of all
animals detected. These surveys resulted in the only observation of a
Dall's porpoise near NBKB, but these surveys do not afford any
information used in take estimation here.
The Navy also conducted vessel-based line transect surveys in Hood
Canal on non-construction days during the 2011 TPP in order to collect
additional data for species present in Hood Canal. These surveys
detected three marine mammal species (harbor seal, California sea lion,
and harbor porpoise), and included surveys conducted in both the main
body of Hood Canal, near the project area, and baseline surveys
conducted for comparison in Dabob Bay, an area of Hood Canal that is
not affected by sound from Navy actions at the NBKB waterfront. The
surveys operated along pre-determined transects that followed a double
saw-tooth pattern to achieve uniform coverage of the entire NBKB
waterfront. The vessel traveled at a speed of approximately 5 kn when
transiting along the transect lines. Two observers recorded sightings
of marine mammals both in the water and hauled out, including the date,
time, species, number of individuals, and behavior (swimming, diving,
etc.). Positions of marine mammals were obtained by recording the
distance and bearing to the animal(s), noting the concurrent location
of the boat with GPS, and subsequently analyzing these data to produce
coordinates of the locations of all animals detected. Sighting
information for harbor porpoises was corrected for detectability (g(0)
= 0.54; Barlow, 1988; Calambokidis et al., 1993; Carretta et al.,
2001).
[[Page 32851]]
Distance sampling methodologies were used to estimate densities of
animals for the data. This information provides the best information
for harbor porpoises.
The cetaceans, as well as the harbor seal, appear to range
throughout Hood Canal; therefore, this analysis assumes that harbor
seal, transient killer whale, and harbor porpoise are uniformly
distributed in the project area. However, it should be noted that there
have been no observations of cetaceans within the floating security
barriers at NBKB; these barriers thus appear to effectively prevent
cetaceans from approaching the shutdown zones. Although the Navy will
implement a precautionary shutdown zone for cetaceans, anecdotal
evidence suggests that cetaceans are not at risk of Level A harassment
at NBKB even from louder activities (e.g., impact pile driving). The
remaining species that occur in the project area, Steller sea lion and
California sea lion, do not appear to utilize most of Hood Canal. The
sea lions appear to be attracted to the man-made haul-out opportunities
along the NBKB waterfront while dispersing for foraging opportunities
elsewhere in Hood Canal. California sea lions were not reported during
aerial surveys of Hood Canal (Jeffries et al., 2000), and Steller sea
lions have been documented almost solely at the NBKB waterfront.
Description of Take Calculation
The take calculations presented here rely on the best data
currently available for marine mammal populations in the Hood Canal.
The formula was developed for calculating take due to pile driving
activity and applied to each group-specific sound impact threshold. The
formula is founded on the following assumptions:
All marine mammal individuals potentially available are
assumed to be present within the relevant area, and thus incidentally
taken;
An individual can only be taken once during a 24-h period;
There were will be 195 total days of activity and the
largest ZOI equals 41.4 km\2\;
Exposure modeling assumes that one impact pile driver and
three vibratory pile drivers are operating concurrently; and,
Exposures to sound levels above the relevant thresholds
equate to take, as defined by the MMPA.
The calculation for marine mammal takes is estimated by:
Exposure estimate = (n * ZOI) * days of total activity
Where:
n = density estimate used for each species/season
ZOI = sound threshold ZOI area; the area encompassed by all
locations where the SPLs equal or exceed the threshold being
evaluated
n * ZOI produces an estimate of the abundance of animals that could
be present in the area for exposure, and is rounded to the nearest
whole number before multiplying by days of total activity.
The ZOI impact area is the estimated range of impact to the sound
criteria. The relevant distances specified in Table 9 were used to
calculate ZOIs around each pile. The ZOI impact area took into
consideration the possible affected area of the Hood Canal from the
pile driving site furthest from shore with attenuation due to land
shadowing from bends in the canal. Because of the close proximity of
some of the piles to the shore, the narrowness of the canal at the
project area, and the maximum fetch, the ZOIs for each threshold are
not necessarily spherical and may be truncated.
While pile driving can occur any day throughout the in-water work
window, and the analysis is conducted on a per day basis, only a
fraction of that time (typically a matter of hours on any given day) is
actually spent pile driving. Acoustic monitoring conducted as part of
the TPP and year one of EHW-2 demonstrated that Level B harassment
zones for vibratory pile driving are likely to be smaller than the
zones estimated through modeling based on measured source levels and
practical spreading loss. Also of note is the fact that the
effectiveness of mitigation measures in reducing takes is typically not
quantified in the take estimation process. In addition, equating
exposure with response (i.e., a behavioral response meeting the
definition of take under the MMPA) is a simplistic and conservative
assumption. For these reasons, these take estimates are likely to be
conservative. See Table 14 for total estimated incidents of take.
Airborne Sound--No incidences of incidental take resulting solely
from airborne sound are likely, as distances to the harassment
thresholds would not reach areas where pinnipeds may haul out. Harbor
seals can haul out at a variety of natural or manmade locations, but
the closest known harbor seal haul-out is at the Dosewallips River
mouth (London, 2006) and Navy waterfront surveys and boat surveys have
found it rare for harbor seals to haul out along the NBKB waterfront
(Agness and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011; DoN,
2013). Individual seals have occasionally been observed hauled out on
pontoons of the floating security fence within the restricted areas of
NBKB, but this area is not within the airborne disturbance ZOI. Nearby
piers are elevated well above the surface of the water and are
inaccessible to pinnipeds, and seals have not been observed hauled out
on the adjacent shoreline. Sea lions typically haul out on submarines
docked at Delta Pier, approximately one mile from the project site.
We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with heads above water. However, these animals would previously have
been `taken' as a result of exposure to underwater sound above the
behavioral harassment thresholds, which are in all cases larger than
those associated with airborne sound. Thus, the behavioral harassment
of these animals is already accounted for in these estimates of
potential take. Multiple incidents of exposure to sound above NMFS'
thresholds for behavioral harassment are not believed to result in
increased behavioral disturbance, in either nature or intensity of
disturbance reaction. Therefore, we do not believe that authorization
of incidental take resulting from airborne sound for pinnipeds is
warranted, and airborne sound is not discussed further here.
California Sea Lion--California sea lions occur regularly in the
vicinity of the project site, with the exception of approximately mid-
June through mid-August, as determined by Navy waterfront surveys
conducted from April 2008 through December 2013 (Table 12). With regard
to the range of this species in Hood Canal and the project area, we
assume on the basis of waterfront observations (Agness and Tannenbaum,
2009; Tannenbaum et al., 2009, 2011; HDR 2012a, 2012b; Hart Crowser,
2013) that the opportunity to haul out on submarines docked at Delta
Pier is a primary attractant for California sea lions in Hood Canal, as
they are not typically observed elsewhere in Hood Canal. Abundance is
calculated as the monthly average of the maximum number observed in a
given month, as opposed to the overall average (Table 12). That is, the
maximum number of animals observed on any one day in a given month was
averaged for 2008-13, providing a monthly average of the maximum daily
number observed. The largest monthly average (71 animals) was recorded
in November, as was the largest single daily count (122 animals). The
first California sea lion was observed at NBKB in August 2009, and
their occurrence has been increasing since that time (DoN, 2013).
[[Page 32852]]
Table 12--California Sea Lion Sighting Information From NBKB, April 2008-December 2013
----------------------------------------------------------------------------------------------------------------
Number of
Number of surveys with Frequency of
Month surveys animals presence \2\ Abundance \3\
present
----------------------------------------------------------------------------------------------------------------
January....................................... 47 36 0.77 31.0
February...................................... 51 44 0.86 39.2
March......................................... 47 45 0.96 53.3
April......................................... 69 57 0.83 43.2
May........................................... 73 58 0.79 24.5
June.......................................... 73 17 0.23 7.4
July.......................................... 67 1 0.01 0.5
August........................................ 67 12 0.18 2.2
September..................................... 58 34 0.59 22.8
October....................................... 69 65 0.94 57.8
November...................................... 65 65 1 70.5
December...................................... 54 44 0.81 49.6
-----------------------------------------------------------------
Total or average (in-water work season 478 301 0.63 33.9
only) \1\................................
----------------------------------------------------------------------------------------------------------------
\1\ Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July-
February) only. Information from March-June presented for reference.
\2\ Frequency is the number of surveys with California sea lions present/number of surveys conducted.
\3\ Abundance is calculated as the monthly average of the maximum daily number observed in a given month.
California sea lion density for Hood Canal was calculated to be
0.28 animals/km\2\ for purposes of the NMSDD (Hanser et al., 2014).
Jeffries et al. (2003) split the Washington inland waters area into
five regions, including Hood Canal as a discrete region. To determine
density, the number of California sea lions known to use haul-outs in
the Hood Canal was identified and then divided by the area of the Hood
Canal to give a total density estimate. However, this density was
derived by averaging data collected year-round. This project will occur
during the designated in-water work window, so it is more appropriate
to use data collected at the NBKB waterfront during those months (July-
February). The average of the monthly averages for maximum daily
numbers observed (in a given month, during the in-water work window) is
33.9 animals (see Table 12). Exposures were calculated assuming 34
individuals could be present, and therefore exposed to sound exceeding
the behavioral harassment threshold, on each day of pile driving. This
methodology is conservative in that it assumes that all individuals
present potentially would be taken on any given day of activity.
Steller Sea Lion
Steller sea lions were first documented at the NBKB waterfront in
November 2008, while hauled out on submarines at Delta Pier, and have
been periodically observed from October to April since that time, as
determined by Navy waterfront surveys conducted from April 2008 through
December 2013 (Table 13). Steller sea lions are occasionally observed
in early May or late September, but have never been observed from
approximately mid-May through mid-September. We assume, on the basis of
waterfront observations (Agness and Tannenbaum, 2009; Tannenbaum et
al., 2009, 2011; HDR 2012a, 2012b; Hart Crowser, 2013), that Steller
sea lions use available haul-outs and foraging habitat similarly to
California sea lions. On occasions when Steller sea lions are observed,
they typically occur in mixed groups with California sea lions also
present, allowing observers to confirm their identifications based on
discrepancies in size and other physical characteristics. (DoN, 2013)
Table 13--Steller Sea Lion Sighting Information From NBKB, April 2008-December 2013
----------------------------------------------------------------------------------------------------------------
Number of
Number of surveys with Frequency of
Month surveys animals presence \2\ Abundance \3\
present
----------------------------------------------------------------------------------------------------------------
January......................................... 47 12 0.26 1.5
February........................................ 51 7 0.14 1.4
March........................................... 47 12 0.26 1.8
April........................................... 69 21 0.30 2.3
May............................................. 73 6 0.08 1.5
June............................................ 73 0 0 0
July............................................ 67 0 0 0
August.......................................... 67 0 0 0
September....................................... 58 2 0.03 0.8
October......................................... 69 30 0.43 3.7
November........................................ 65 37 0.57 5.7
December........................................ 54 18 0.33 2.6
---------------------------------------------------------------
Total or average (in-water work season only) 478 106 0.22 2.0
\1\........................................
----------------------------------------------------------------------------------------------------------------
\1\ Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July-
February) only. Information from March-June presented for reference.
\2\ Frequency is the number of surveys with Steller sea lions present/number of surveys conducted.
\3\ Abundance is calculated as the monthly average of the maximum daily number observed in a given month.
[[Page 32853]]
Abundance is calculated in the same manner described for California
sea lions (Table 13). That is, the maximum number of animals observed
on any one day in a given month was averaged for 2008-13, providing a
monthly average of the maximum daily number observed. The largest
monthly average (six animals) was recorded in November, as was the
largest single daily count (eleven animals). NMSDD density for Steller
sea lions was also calculated in a similar manner as that for
California sea lions (0.03 animals/km\2\; Hanser et al., 2014) and, as
for California sea lions, local abundance data specific to the in-water
work window is the most appropriate information for use in estimating
take. The average of the monthly averages for maximum daily numbers
observed (in a given month, during the in-water work window) is two
animals (see Table 13). However, in recognition that numbers of Steller
sea lions have been increasing every year and reflecting a more typical
group size when Steller sea lions have been observed, the Navy has
requested a precautionary assumption that three individuals could be
present, and therefore exposed to sound exceeding the behavioral
harassment threshold, on each day of pile driving.
Harbor Seal--The harbor seal density used here is the same as that
in the NMSDD (Hanser et al., 2014). Jeffries et al. (2003) conducted
aerial surveys of harbor seals in 1999 for the Washington Department of
Fish and Wildlife, dividing the survey areas into seven strata
(including five in inland waters and two in coastal waters). Survey
effort in the Hood Canal stratum yielded a count of 711 harbor seals
hauled out. To account for animals in the water and not observed during
survey counts, a correction factor of 1.53 was applied (Huber et al.,
2001) to derive a total Hood Canal population of 1,088 seals. The
correction factor (1.53) was based on the proportion of time seals
spend on land versus in the water over the course of a day, and was
derived by dividing one by the percentage of time harbor seals spent on
land. These data came from tags (VHF transmitters) applied to harbor
seals at six areas (Grays Harbor, Tillamook Bay, Umpqua River, Gertrude
Island, Protection/Smith Islands, and Boundary Bay, BC) within two
different harbor seal stocks (the coastal stock and the Washington
inland waters stock) over four survey years. Although the sampling
areas included both coastal and inland waters, with pooled correction
factors of 1.50 and 1.57, respectively, Huber et al. (2001) found no
significant difference in the proportion of seals ashore among the six
sites and no interannual variation at one site studied across years.
Therefore, we retain the total pooled correction factor of 1.53 here.
The Hood Canal population is part of the inland waters stock, and while
not specifically sampled, Jeffries et al. (2003) found the VHF data to
be broadly applicable to the entire Washington harbor seal population.
Using this information and the area of the Hood Canal stratum yields a
density estimate of 3.04 animals/km\2\.
However, to determine an instantaneous in-water density estimate, a
secondary correction must be applied to account for harbor seals that
are hauled out at any given moment. The tagging research in 1991 and
1992 conducted by Huber et al. (2001) was repeated for two sites by
Jeffries et al. (2003), using the same methods for the 1999 and 2000
survey years. These surveys indicated that approximately 35 percent of
harbor seals are in the water versus hauled out on a daily basis (Huber
et al., 2001; Jeffries et al., 2003). A corrected density was derived
from the number of harbor seals that are present in the water at any
one time (35 percent of 1,088, or approximately 381 individuals),
divided by the area of the Hood Canal, yielding an estimate of 1.06
animals/km\2\.
We recognize that over the course of the day, while the proportion
of animals in the water may not vary significantly, different
individuals may enter and exit the water (i.e., it is probable that
greater than 35 percent of seals will enter the water at some point
during the day). Therefore, an instantaneous estimate of animals in the
water at a given time may not produce an accurate assessment of the
number of individuals that enter the water over the daily duration of
the activity. However, no data exist regarding fine-scale harbor seal
movements within the project area on time durations of less than a day,
thus precluding an assessment of ingress or egress of different animals
through the action area. As such, it is impossible, given available
data, to determine exactly what number of individuals above 35 percent
may potentially be exposed to underwater sound. Therefore, we are left
to make a decision, on the basis of limited available information,
regarding which of these two scenarios (i.e., 100 percent versus 35
percent of harbor seals are in the water and exposed to sound) produces
a more accurate estimate of the potential incidents of take.
First, we understand that hauled-out harbor seals are necessarily
at haul-outs. No significant harbor seal haul-outs are located within
or near the action area. Harbor seals observed in the vicinity of the
NBKB shoreline are rarely hauled-out (for example, in formal surveys
during 2007-08, approximately 86 percent of observed seals were
swimming), and when hauled-out, they do so opportunistically (i.e., on
floating booms rather than established haul-outs). Harbor seals are
typically unsuited for using manmade haul-outs at NBKB, which are used
by the larger sea lions. Primary harbor seal haul-outs in Hood Canal
are generally located at significant distance (20 km or more) from the
action area in Dabob Bay or further south (see Figure 4-1 in the Navy's
application), meaning that animals casually entering the water from
haul-outs or flushing due to some disturbance at those locations would
not be exposed to underwater sound from the project; rather, only those
animals embarking on foraging trips and entering the action area may be
exposed.
Second, we know that harbor seals in Hood Canal are not likely to
have a uniform distribution as is assumed through use of a density
estimate, but are likely to be relatively concentrated near areas of
interest such as the haul-outs found in Dabob Bay or foraging areas.
The majority of the action area consists of the Level B harassment zone
in deeper waters of Hood Canal; past observations from surveys and
required monitoring have confirmed that harbor seals are less abundant
in these waters.
Third, a typical pile driving day (in terms of the actual time
spent driving) is somewhat shorter than may be assumed (i.e., 8-15
hours) as a representative pile driving day based on daylight hours.
Construction scheduling and notional production rates in concert with
typical delays mean that hammers are active for only some fraction of
time on pile driving ``days''. During the first two years of
construction for EHW-2, pile driving occurred over approximately 1,778
hours on 242 days, for an approximate average of seven hours per pile
driving day.
What we know tells us that (1) the turnover of harbor seals (in and
out of the water) is occurring primarily outside the action area and
would not be expected to result in a greater number of individuals
entering the action area within a given day and being harassed than is
assumed; (2) there are likely to
[[Page 32854]]
be significantly fewer harbor seals in the majority of the action area
than would be indicated by the uncorrected density; and (3) pile
driving actually occurs over a limited timeframe on any given day
(i.e., less total time per day than would be assumed based on daylight
hours and non-continuously), reducing the amount of time over which new
individuals might enter the action area within a given day. These
factors lead us to believe that the corrected density is likely to more
closely approximate the number of seals that may be found in the action
area than does the uncorrected density, and there are no existing data
that would indicate that the proportion of individuals entering the
water within the predicted area of effect during pile driving would be
dramatically larger than 35 percent. Therefore, using 100 percent of
the population to estimate density would likely result in a gross
exaggeration of potential take. Moreover, because the Navy is typically
unable to determine from field observations whether the same or
different individuals are being exposed, each observation is recorded
as a new take, although an individual theoretically would only be
considered as taken once in a given day.
Finally, we note that during the course of four previous IHAs over
two years (2011-12), the Navy was authorized for 6,725 incidents of
incidental harassment (corrected for actual number of pile driving
days). The total estimate of actual incidents of take (observed takes
and observations extrapolated to unobserved area) was 868. This is
almost certainly negatively biased, but the huge disparity does provide
confirmation that we are not significantly underestimating takes.
Killer Whales--Transient killer whales are uncommon visitors to
Hood Canal, and may be present anytime during the year. Transient pods
(six to eleven individuals per event) were observed in Hood Canal for
lengthy periods of time (59-172 days) in 2003 (January-March) and 2005
(February-June), feeding on harbor seals (London, 2006). These whales
used the entire expanse of Hood Canal for feeding. The NMSDD used
monthly unique sightings data collected over the period 2004-2010 and
an average group size of 5.16 (Houghton et al., in prep.) to calculate
densities on a seasonal basis for each of five geographic strata
(Hanser et al., 2014). Densities for the Hood Canal stratum range from
0-0.0006 animals/km\2\ across all seasons, which would result in a
prediction that zero animals would be harassed by the project
activities.
However, while transient killer whales are rare in the Hood Canal,
it is possible that a pod of animals could be present. In the event
that this occurred in a similar manner to prior occurrences (e.g., 59-
172 days) and incidental take were not authorized appropriately, there
could be significant project delays. In estimating potential incidences
of take here, we make three assumptions: (1) Transient killer whales
have a reasonable likelihood of occurrence in the project area; (2) if
whales were present, they would occur in a pod of six animals (the
minimum pod size seen in the 2003/2005 events but equivalent to the
average pod size reported by Houghton et al. [in prep.]); and (3) the
pod would be present for thirty days. This last assumption represents
only half of the minimum time killer whales were present during the
2003/2005 events; however, we believe that it is unlikely the whales
would remain in the area for a longer period in the presence of a
harassing stimulus (i.e., pile driving). In the absence of any
overriding contextual element (e.g., NBKB is not important as a
breeding area, and provides no unusual concentration of prey), it is
reasonable to assume that whales would leave the area if exposed to
potentially harassing levels of sound on each day that they were
present. In summary, we assume here that, if killer whales occurred in
the project area, a pod of six whales would be present--and could
potentially be harassed--for thirty days.
Harbor Porpoise--During vessel-based line transect surveys on non-
construction days during the TPP, harbor porpoises were frequently
sighted within several kilometers of the base, mostly to the north or
south of the project area, but occasionally directly across from the
NBKB waterfront on the far side of Toandos Peninsula. Harbor porpoise
presence in the immediate vicinity of the base (i.e., within one
kilometer) remained low. These data were used to generate a density for
Hood Canal. Based on guidance from other line transect surveys
conducted for harbor porpoises using similar monitoring parameters
(e.g., boat speed, number of observers) (Barlow, 1988; Calambokidis et
al., 1993; Carretta et al., 2001), the Navy determined the effective
strip width for the surveys to be one kilometer, or a perpendicular
distance of 500 m from the transect to the left or right of the vessel.
The effective strip width was set at the distance at which the
detection probability for harbor porpoises was equivalent to one, which
assumes that all individuals on a transect are detected. Only sightings
occurring within the effective strip width were used in the density
calculation. By multiplying the trackline length of the surveys by the
effective strip width, the total area surveyed during the surveys was
471.2 km\2\. Thirty-eight individual harbor porpoises were sighted
within this area, resulting in a density of 0.0806 animals/km\2\. To
account for availability bias, or the animals which are unavailable to
be detected because they are submerged, the Navy utilized a g(0) value
of 0.54, derived from other similar line transect surveys (Barlow,
1988; Calambokidis et al., 1993; Carretta et al., 2001). This resulted
in a corrected density of 0.149 animals/km\2\.
Table 14--Number of Potential Incidental Takes of Marine Mammals Within Various Acoustic Threshold Zones
----------------------------------------------------------------------------------------------------------------
Underwater
-------------------------------- Total proposed
Species Density Level B 120 authorized takes
Level A dB) \1\ \2\
----------------------------------------------------------------------------------------------------------------
California sea lion.......................... \3\ 34 0 6,630 6,630
Steller sea lion............................. \3\ 2 0 585 585
Harbor seal.................................. 1.06 0 8,580 8,580
Killer whale (transient)..................... n/a 0 180 \4\ 180
Harbor porpoise.............................. 0.149 0 1,170 1,170
----------------------------------------------------------------------------------------------------------------
\1\ The 160-dB acoustic harassment zone associated with impact pile driving would always be subsumed by the 120-
dB harassment zone produced by vibratory driving. Therefore, takes are not calculated separately for the two
zones.
[[Page 32855]]
\2\ For species with associated density, density was multiplied by largest ZOI (i.e., 41.4 km). The resulting
value was rounded to the nearest whole number and multiplied by the 195 days of activity. For species with
abundance only, that value was multiplied directly by the 195 days of activity. We assume for reasons
described earlier that no takes would result from airborne noise.
\3\ Figures presented are abundance numbers, not density, and are calculated as the average of average daily
maximum numbers per month (see Tables 12-13). Abundance numbers are rounded to the nearest whole number for
take estimation. The Steller sea lion abundance was increased to three for take estimation purposes.
\4\ We assumed that a single pod of six killer whales could be present for as many as 30 days of the duration.
Analyses and Preliminary Determinations
Negligible Impact Analysis
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as an
impact resulting from the specified activity that cannot be reasonably
expected to, and is not reasonably likely to, adversely affect the
species or stock through effects on annual rates of recruitment or
survival. A negligible impact finding is based on the lack of likely
adverse effects on annual rates of recruitment or survival (i.e.,
population-level effects). An estimate of the number of 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, we consider other factors, such as the likely nature of any
responses (e.g., intensity, duration), the context of any responses
(e.g., critical reproductive time or location, migration), as well as
the number and nature of estimated Level A harassment takes, the number
of estimated mortalities, and effects on habitat.
Pile driving activities associated with the wharf construction
project, as outlined previously, have the potential to disturb or
displace marine mammals. Specifically, the specified activities may
result in take, in the form of Level B harassment (behavioral
disturbance) only, from underwater sounds generated from pile driving.
Potential takes could occur if individuals of these species are present
in the ensonified zone when pile driving is happening, which is likely
to occur because (1) harbor seals, which are frequently observed along
the NBKB waterfront, are present within the WRA; (2) sea lions, which
are less frequently observed, transit the WRA en route to haul-outs to
the south at Delta Pier; or (3) cetaceans or pinnipeds transit the
larger Level B harassment zone outside of the WRA.
No injury, serious injury, or mortality is anticipated given the
methods of installation and measures designed to minimize the
possibility of injury to marine mammals. The potential for these
outcomes is minimized through the construction method and the
implementation of the planned mitigation measures. Specifically,
vibratory hammers will be the primary method of installation, and this
activity does not have significant potential to cause injury to marine
mammals due to the relatively low source levels produced (likely less
than 180 dB rms) and the lack of potentially injurious source
characteristics. Impact pile driving produces short, sharp pulses with
higher peak levels and much sharper rise time to reach those peaks.
When impact driving is necessary, required measures (use of a sound
attenuation system, which reduces overall source levels as well as
dampening the sharp, potentially injurious peaks, and implementation of
shutdown zones) significantly reduce any possibility of injury. Given
sufficient ``notice'' through use of soft start (for impact driving),
marine mammals are expected to move away from a sound source that is
annoying prior to its becoming potentially injurious. The likelihood
that marine mammal detection ability by trained observers is high under
the environmental conditions described for Hood Canal further enables
the implementation of shutdowns to avoid injury, serious injury, or
mortality.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from past
projects at NBKB, will likely be limited to reactions such as increased
swimming speeds, increased surfacing time, or decreased foraging (if
such activity were occurring). Most likely, individuals will simply
move away from the sound source and be temporarily displaced from the
areas of pile driving, although even this reaction has been observed
primarily only in association with impact pile driving. In response to
vibratory driving, harbor seals (which may be somewhat habituated to
human activity along the NBKB waterfront) have been observed to orient
towards and sometimes move towards the sound. Repeated exposures of
individuals to levels of sound that may cause Level B harassment are
unlikely to result in hearing impairment or to significantly disrupt
foraging behavior. Thus, even repeated Level B harassment of some small
subset of the overall stock is unlikely to result in any significant
realized decrease in fitness to those individuals, and thus would not
result in any adverse impact to the stock as a whole. Level B
harassment will be reduced to the level of least practicable impact
through use of mitigation measures described herein and, if sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the project area while the activity is
occurring.
For pinnipeds, no rookeries are present in the project area, there
are no haul-outs other than those provided opportunistically by man-
made objects, and the project area is not known to provide foraging
habitat of any special importance (other than is afforded by the known
migration of salmonids generally along the Hood Canal shoreline). No
cetaceans are expected within the WRA. The pile driving activities
analyzed here are similar to other nearby construction activities
within the Hood Canal, including recent projects conducted by the Navy
at the same location (TPP and EHW-1 pile replacement project, Years 1-2
of EHW-2; barge mooring project) as well as work conducted in 2005 for
the Hood Canal Bridge (SR-104) by the Washington State Department of
Transportation, which have taken place with no reported injuries or
mortality to marine mammals, and no known long-term adverse
consequences from behavioral harassment.
In summary, this negligible impact analysis is founded on the
following factors: (1) The possibility of injury, serious injury, or
mortality may reasonably be considered discountable; (2) the
anticipated incidences of Level B harassment consist of, at worst,
temporary modifications in behavior; (3) the absence of any major
rookeries and only a few isolated and opportunistic haul-out areas near
or adjacent to the project site; (4) the absence of cetaceans within
the WRA and generally sporadic occurrence outside the WRA; (5) the
absence of any other known areas or features of special significance
for foraging or reproduction within the project area; and (6) the
presumed efficacy of the planned mitigation measures in reducing the
effects of the specified activity to the level of least practicable
impact. In addition, none of these stocks are listed under the ESA or
designated as depleted under the MMPA. All of the stocks for which take
is authorized are thought to be
[[Page 32856]]
increasing or to be within OSP size. In combination, we believe that
these factors, as well as the available body of evidence from other
similar activities, including those conducted at the same time of year
and in the same location, demonstrate that the potential effects of the
specified activity will have only short-term effects on individuals.
The specified activity is not expected to impact rates of recruitment
or survival and will therefore not result in population-level impacts.
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, we preliminarily find that the total marine mammal
take from Navy's wharf construction activities will have a negligible
impact on the affected marine mammal species or stocks.
Small Numbers Analysis
The numbers of animals authorized to be taken for Steller and
California sea lions would be considered small relative to the relevant
stocks or populations (less than one percent for Steller sea lions and
less than three percent for California sea lions) even if each
estimated taking occurred to a new individual--an extremely unlikely
scenario. For pinnipeds occurring at the NBKB waterfront, there will
almost certainly be some overlap in individuals present day-to-day.
Further, for the pinniped species, these takes could potentially occur
only within some small portion of the overall regional stock. For
example, of the estimated 296,500 California sea lions, only certain
adult and subadult males--believed to number approximately 3,000-5,000
by Jeffries et al. (2000)--travel north during the non-breeding season.
That number has almost certainly increased with the population of
California sea lions--the 2000 SAR for California sea lions reported an
estimated population size of 204,000-214,000 animals--but likely
remains a relatively small portion of the overall population.
For harbor seals, animals found in Hood Canal belong to a closed,
resident population estimated at approximately 1,000 animals by
Jeffries et al. (2003), and takes are likely to occur only within some
portion of that closed population, rather than to animals from the
Washington inland waters stock as a whole. The animals that are
resident to Hood Canal, to which any incidental take would accrue,
represent only seven percent of the best estimate of regional stock
abundance. For transient killer whales, we estimate take based on an
assumption that a single pod of whales, comprising six individuals, is
present in the vicinity of the project area for the entire duration of
the project. These six individuals represent a small number of
transient killer whales, for which a conservative minimum estimate of
243 animals is given in the draft 2013 SAR.
Little is known about harbor porpoise use of Hood Canal, and prior
to monitoring associated with recent pile driving projects at NBKB, it
was believed that harbor porpoises were infrequent visitors to the
area. It is unclear from the limited information available what
relationship harbor porpoise occurrence in Hood Canal may hold to the
regional stock or whether similar usage of Hood Canal may be expected
to be recurring. It is unknown how many unique individuals are
represented by sightings in Hood Canal, although it is unlikely that
these animals represent a large proportion of the overall stock. While
we believe that the authorized numbers of incidental take would be
likely to occur to a much smaller number of individuals, the number of
incidents of take relative to the stock abundance (approximately eleven
percent) remains within the bounds of what we consider to be small
numbers.
As summarized here, the estimated numbers of potential incidents of
harassment for these species are likely much higher than will
realistically occur. This is because (1) we use the maximum possible
number of days (195) in estimating take, despite the fact that multiple
delays and work stoppages are likely to result in a lower number of
actual pile driving days; (2) sea lion estimates rely on the averaged
maximum daily abundances per month, rather than simply an overall
average which would provide a much lower abundance figure; and (3) the
estimates for transient killer whales use sparse information to attempt
to account for the potential presence of species that have not been
observed in Hood Canal since 2005. In addition, potential efficacy of
mitigation measures in terms of reduction in numbers and/or intensity
of incidents of take has not been quantified. Therefore, these
estimated take numbers are likely to be precautionary. 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, we preliminarily find 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 relevant subsistence uses of marine mammals implicated
by this action. Therefore, we have determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
No marine mammal species listed under the ESA are expected to be
affected by these activities. Therefore, we have determined that a
section 7 consultation under the ESA is not required.
National Environmental Policy Act (NEPA)
In compliance with the NEPA of 1969 (42 U.S.C. 4321 et seq.), as
implemented by the regulations published by the Council on
Environmental Quality (CEQ; 40 CFR parts 1500-1508), the Navy prepared
an Environmental Impact Statement (EIS) and issued a Record of Decision
(ROD) for this project. We acted as a cooperating agency in the
preparation of that document, and reviewed the EIS and the public
comments received and determined that preparation of additional NEPA
analysis was not necessary. In compliance with NEPA, the CEQ
regulations, and NOAA Administrative Order 216-6, we subsequently
adopted the Navy's EIS and issued our own ROD for the issuance of the
first IHA on July 6, 2012, and reaffirmed the ROD before issuing a
second IHA in 2013.
We have reviewed the Navy's application for a renewed IHA for
ongoing construction activities for 2014-15 and the 2013-14 monitoring
report. Based on that review, we have determined that the proposed
action is very similar to that considered in the previous IHAs. In
addition, no significant new circumstances or information relevant to
environmental concerns have been identified. Thus, we have determined
preliminarily that the preparation of a new or supplemental NEPA
document is not necessary, and will, after review of public comments
determine whether or not to reaffirm our 2012 ROD. The 2012 NEPA
documents are available for review at https://www.nmfs.noaa.gov/pr/permits/incidental.htm.
Proposed Authorization
As a result of these preliminary determinations, we propose to
issue an IHA to the Navy for conducting the described wharf
construction activities
[[Page 32857]]
in the Hood Canal, from July 16, 2014 through February 15, 2015,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. The proposed IHA language is provided
next.
This section contains a draft of the IHA itself. The wording
contained in this section is proposed for inclusion in the IHA (if
issued).
1. This Incidental Harassment Authorization (IHA) is valid from
July 16, 2014 through February 15, 2015.
2. This IHA is valid only for pile driving and removal activities
associated with construction of Explosive Handling Wharf 2
(EHW-2) in the Hood Canal, Washington.
3. General Conditions
(a) A copy of this IHA must be in the possession of the Navy, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species authorized for taking are the harbor seal (Phoca
vitulina), California sea lion (Zalophus californianus), killer whale
(transient only; Orcinus orca), Steller sea lion (Eumetopias jubatus),
and the harbor porpoise (Phocoena phocoena).
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b). See Table 1 (attached) for numbers of
take authorized.
(d) The taking by injury (Level A harassment), serious injury, or
death of any of the species listed in condition 3(b) of the
Authorization or any taking of any other species of marine mammal is
prohibited and may result in the modification, suspension, or
revocation of this IHA.
(e) The Navy shall conduct briefings between construction
supervisors and crews, marine mammal monitoring team, and Navy staff
prior to the start of all pile driving activity, and when new personnel
join the work, in order to explain responsibilities, communication
procedures, marine mammal monitoring protocol, and operational
procedures.
4. Mitigation Measures
In order to ensure the least practicable impact on the species
listed in condition 3(b), the holder of this Authorization is required
to implement the following mitigation measures:
(a) During impact pile driving, the Navy shall implement a minimum
shutdown zone of 20 m radius around the pile, to be effective for all
species of pinniped, and a minimum shutdown zone of 85 m radius around
the pile, to be effective for all species of cetacean. If a marine
mammal comes within the relevant zone, such operations shall cease. No
marine mammal shall be exposed to sound pressure levels equaling or
exceeding 180/190 dB rms (re 1 [mu]Pa) for cetaceans and pinnipeds,
respectively, in order to prevent unauthorized Level A harassment.
(b) During vibratory pile driving and removal, the Navy shall
implement a minimum shutdown zone of 10 m radius around the pile for
marine mammals. If a marine mammal comes within this zone, such
operations shall cease. No marine mammal shall be exposed to sound
pressure levels equaling or exceeding 180/190 dB rms (re 1 [mu]Pa) for
cetaceans and pinnipeds, respectively, in order to prevent unauthorized
Level A harassment.
(c) The Navy shall similarly avoid direct interaction with marine
mammals during in-water heavy machinery work other than pile driving
that may occur in association with the wharf construction project. If a
marine mammal comes within 10 m of such activity, operations shall
cease and vessels shall reduce speed to the minimum level required to
maintain steerage and safe working conditions, as appropriate.
(d) The Navy shall establish monitoring locations as described in
the Marine Mammal Monitoring Plan (Monitoring Plan; attached). For all
pile driving activities, a minimum of one observer shall be assigned to
each active pile driving rig in order to monitor the shutdown zones,
while at least two additional observers shall be positioned for optimal
monitoring of the surrounding waters within the Waterfront Restricted
Area (WRA). These observers shall record all observations of marine
mammals, regardless of distance from the pile being driven, as well as
behavior and potential behavioral reactions of the animals.
(e) Monitoring shall take place from 15 minutes prior to initiation
of pile driving activity through 30 minutes post-completion of pile
driving activity. Pre-activity monitoring shall be conducted for 15
minutes to ensure that the shutdown zone is clear of marine mammals,
and pile driving may commence when observers have declared the shutdown
zone clear of marine mammals. In the event of a delay or shutdown of
activity resulting from marine mammals in the shutdown zone, animals
shall be allowed to remain in the shutdown zone (i.e., must leave of
their own volition) and their behavior shall be monitored and
documented. Monitoring shall occur throughout the time required to
drive a pile. The shutdown zone must be determined to be clear during
periods of good visibility (i.e., the entire shutdown zone and
surrounding waters within the WRA must be visible to the naked eye).
(f) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted (i.e.,
implementation of shutdown at one pile driving location may not
necessarily trigger shutdown at other locations when pile driving is
occurring concurrently). If pile driving is halted or delayed at a
specific location due to the presence of a marine mammal, the activity
may not commence or resume until either the animal has voluntarily left
and been visually confirmed beyond the shutdown zone or 15 minutes have
passed without re-detection of the animal.
(g) Monitoring shall be conducted by qualified observers, as
described in the Monitoring Plan. Trained observers shall be placed
from the best vantage point(s) practicable to monitor for marine
mammals and implement shutdown or delay procedures when applicable
through communication with the equipment operator.
(h) Approved sound attenuation devices shall be used during impact
pile driving operations. The Navy shall implement the necessary
contractual requirements to ensure that such devices are capable of
achieving optimal performance, and that deployment of the device is
implemented properly such that no reduction in performance may be
attributable to faulty deployment.
(i) The Navy shall use soft start techniques recommended by NMFS
for impact pile driving. The soft start requires contractors to provide
an initial set of strikes from the impact hammer at reduced energy,
followed by a 30-second waiting period, then two subsequent reduced
energy strike sets. Soft start shall be implemented at the start of
each day's impact pile driving and at any time following cessation of
impact pile driving for a period of 30 minutes or longer.
(j) Pile driving shall only be conducted during daylight hours.
5. Monitoring
The holder of this Authorization is required to conduct marine
mammal monitoring during pile driving activity. Marine mammal
monitoring and reporting shall be conducted in accordance with the
Monitoring Plan.
(a) The Navy shall collect sighting data and behavioral responses
to pile driving for marine mammal species observed in the region of
activity during the period of activity. All observers shall be trained
in marine mammal identification and behaviors, and shall
[[Page 32858]]
have no other construction related tasks while conducting monitoring.
(b) For all marine mammal monitoring, the information shall be
recorded as described in the Monitoring Plan.
6. Reporting
The holder of this Authorization is required to:
(a) Submit a draft report on all marine mammal monitoring conducted
under the IHA within 90 calendar days of the end of the in-water work
period. A final report shall be prepared and submitted within 30 days
following resolution of comments on the draft report from NMFS. This
report must contain the informational elements described in the
Monitoring Plan, at minimum (see attached).
(b) Reporting injured or dead marine mammals:
i. In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this IHA,
such as an injury (Level A harassment), serious injury, or mortality,
Navy shall immediately cease the specified activities and report the
incident to the Office of Protected Resources (301-427-8425), NMFS, and
the West Coast Regional Stranding Coordinator (206-526-6550), NMFS. The
report must include the following information:
A. Time and date of the incident;
B. Description of the incident;
C. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
D. Description of all marine mammal observations in the 24 hours
preceding the incident;
E. Species identification or description of the animal(s) involved;
F. Fate of the animal(s); and
G. Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with Navy to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. Navy may not resume
their activities until notified by NMFS.
i. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), Navy shall immediately report
the incident to the Office of Protected Resources, NMFS, and the West
Coast Regional Stranding Coordinator, NMFS.
The report must include the same information identified in 6(b)(i)
of this IHA. Activities may continue while NMFS reviews the
circumstances of the incident. NMFS will work with Navy to determine
whether additional mitigation measures or modifications to the
activities are appropriate.
ii. In the event that Navy discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, scavenger damage), Navy shall report the incident to the
Office of Protected Resources, NMFS, and the West Coast Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. Navy
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
the authorized taking is having more than a negligible impact on the
species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analysis, the draft authorization, and
any other aspect of this Notice of Proposed IHA for Navy's wharf
construction activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on Navy's request for an MMPA authorization.
Dated: May 27, 2014.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2014-12906 Filed 6-5-14; 8:45 am]
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