[Federal Register Volume 75, Number 54 (Monday, March 22, 2010)]
[Notices]
[Pages 13502-13514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-6248]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XU03
Takes of Marine Mammals Incidental to Specified Activities;
Manette Bridge Replacement in Bremerton, Washington
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
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SUMMARY: NMFS has received an application from the Washington State
Department of Transportation (WSDOT) for an Incidental Harassment
Authorization (IHA) to take marine mammals, by harassment, incidental
to construction and demolition activities related to the replacement of
the Manette Bridge in Bremerton, Washington. Pursuant to the Marine
Mammal Protection Act (MMPA), NMFS is requesting comments on its
proposal to issue an IHA to WSDOT to incidentally harass, by Level B
Harassment only, three species of marine mammals during the specified
activity.
DATES: Comments and information must be received no later than April
21, 2010.
ADDRESSES: Comments on the application should be addressed to Michael
Payne, Chief, Permits, Conservation and Education Division, Office of
Protected Resources, National Marine Fisheries Service, 1315 East-West
Highway, Silver Spring, MD 20910-3225. The mailbox address for
providing email comments is [email protected]. NMFS is not responsible
for e-mail comments sent to addresses other than the one provided here.
Comments sent via e-mail, including all attachments, must not exceed a
10-megabyte file size.
Instructions: All comments received are a part of the public record
and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information
(for example, name, address, etc.) voluntarily submitted by the
commenter may be publicly accessible. Do not submit Confidential
Business Information or otherwise sensitive or protected information.
A copy of the application containing a list of the references used
in this document may be obtained by writing to the address specified
above, telephoning the contact listed below (see FOR FURTHER
INFORMATION CONTACT), or visiting the internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this
notice may also be viewed, by appointment, during regular business
hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected
Resources, NMFS, (301) 713-2289, ext 137.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103
as ''...an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the United States can apply for an authorization
to incidentally take small numbers of marine mammals by harassment.
Section 101(a)(5)(D) establishes a 45-
[[Page 13503]]
day time limit for NMFS review of an application followed by a 30-day
public notice and comment period on any proposed authorizations for the
incidental harassment of marine mammals. Within 45 days of the close of
the comment period, NMFS must either issue or deny the authorization.
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as:
any act of pursuit, torment, or annoyance which (i) has the
potential to injure a marine mammal or marine mammal stock in the
wild [Level A harassment]; or (ii) has the potential to disturb a
marine mammal or marine mammal stock in the wild by causing
disruption of behavioral patterns, including, but not limited to,
migration, breathing, nursing, breeding, feeding, or sheltering
[Level B harassment].
Summary of Request
NMFS received an application on December 24, 2009, from WSDOT for
the taking, by harassment, of marine mammals incidental to construction
and demolition work related to the Manette Bridge replacement in
Bremerton, Washington, starting in early June 2010.
The Manette Bridge is located within the Puget Sound of Washington
State, at the outlet to the Port Washington Narrows. The Port
Washington Narrows provides the only outlet from Dyes Inlet to Sinclair
Inlet, and connection to the greater Puget Sound. The Manette Bridge is
determined to be a functionally obsolete and structurally deficient
bridge that requires replacement, and the WSDOT is planning to have it
replaced. The proposed bridge replacement work includes the following
activities:
Construction of temporary work trestles, which involves
steel pile installation using both vibratory and impact driving
methods;
Construction of new bridge piers, which involves
excavation of benthic material;
Barge anchoring and usage;
Removal of existing bridge; and
Removal of temporary work platforms.
Since marine mammal species and stocks in the proposed action area
could be affected by the proposed bridge replacement activities, the
WSDOT is seeking an IHA that would allow the incidental, but not
intentional, take of marine mammals by Level B behavioral harassment
during the construction of the new Manette Bridge and removal of the
existing bridge. The WSDOT states that small numbers of three species
of marine mammals could potentially be taken by pile driving or other
construction activities associated with the bridge replacement work.
However, with the proposed mitigation and monitoring measures, the
numbers and levels of marine mammal takes would be reduced to the least
amount practicable.
Description of the Specific Activity
The Manette Bridge was originally built in 1930. The bridge was
constructed with five steel truss main spans on six concrete piers,
elements which are still part of today's bridge. A 1949 contract
replaced the original wooden deck and timber trusses in the outer spans
with concrete and steel. The primary areas of structural deficiencies
are in the concrete piers and the structural steel trusses, which are
nearing 80 years old. The concrete in the foundations is in varying
states of deterioration. Testing and analysis of concrete taken from
the main piers by WSDOT from 1976 through 2003 determined that
deterioration in the concrete has resulted from a process called Alkali
Silica Reaction (ASR).
ASR causes deterioration of mortars and concretes due to the
swelling of gel formed by the reaction of alkali in cement-based
materials with reactive silica in aggregates in the presence of water.
The swelling of the gel generates tensile stresses in the specimen
resulting in expansion and cracks. There is no known way to mitigate
and fully address the ASR problem in the concrete foundations of the
six piers supporting the steel truss spans.
Overall, the WSDOT determined that the substructure components of
the existing Manette Bridge are in poor condition at the main piers
(built in 1930) and in satisfactory condition at the approach piers
(built in 1949). Columns and pier walls at the main spans exhibit
leaching cracks, rust stains, delaminations, soft concrete, and
formwork holes. Exposed rebar is visible above and below the tidal
zone, however mass marine growth prevents an exact detailing of this
exposure.
The foundation is exposed at all piers in varying degrees. Main
Piers 2 and 3 are in the worst condition with the original footing and
seals now indeterminate from each other. At the corners, corroded
remnants of rebar are visible where the footings have been rounded to
an approximate 4-ft (1.22-m) radius. Several cofferdams have been
constructed around the different piers to shore up soft concrete. Some
undermining is occurring at these piers due to local scour conditions.
Contract repairs to the main concrete piers were completed in 1949
(Piers 4 and 6) and 1991 (Pier 5) and 1996 (Piers 4 and 6). These
repairs attempted to encase the deteriorating concrete in the concrete
foundations but were not effective since the core concrete with ASR
continues to deteriorate.
In 1993, the WSDOT Bridge Engineer identified that the bridge
superstructure (trusses and deck) could be rehabilitated to provide 20
or more years of additional service life. The cost to totally
rehabilitate this bridge by: encasing and repairing all the concrete
main piers; replacing corroded steel including rivets and connections;
repainting the entire bridge and replacing the bridge deck could exceed
50-75% of the replacement costs. However, there are no practical means
to restore or prevent further deterioration in the column and footing
concrete. The condition of the reinforcing steel in the highly
fractured substructure concrete is an added unknown. As a result of
this assessment, the WSDOT determined that replacement of the bridge is
warranted and necessary.
The proposed bridge replacement project would replace the
structurally deficient and functionally obsolete Manette Bridge in the
City of Bremerton with a new concrete bridge. The new Manette Bridge
would be built parallel to, and immediately south of, the existing
bridge with roadway connections to existing city street intersections
on each end of the bridge. Construction of the project is proposed to
begin in 2010 and continue for approximately 3 years.
The project would occur in three main phases. Construction sequence
plan sheets are included in Appendix A of the WSDOT IHA application.
First, the new bridge piers and central portion of the new bridge will
be constructed. Second, the outermost spans of the existing bridge will
be removed and the new bridge's outermost spans and abutments will be
built. This work includes the completion of stormwater facilities for
the new bridge. Finally, the remaining portions of the existing bridge
will be demolished and removed. The construction elements associated
with these phases are summarized below.
The construction of the new bridge would require the construction
of new piers and demolition of existing piers, all of which include
work below the mean lower low water (MLLW) mark. An estimated 3,900
cubic yards of concrete would be placed below the MLLW mark for the new
bridge piers. Temporary work trestles would be built in Port Washington
Narrows as part of this project to support both the construction of the
new bridge and demolition of the existing bridge. This
[[Page 13504]]
also would include work below the MLLW mark. Barges would be used to
transport and stage equipment and materials. They would be tethered
with mooring lines and temporarily anchored buoys.
The footprint of the proposed approaches and abutments is primarily
located within the existing bridge footprint. However, an additional
0.75 acre of land would be temporarily disturbed during construction
and 0.15 acre of land would be permanently converted to roadway.
Work trestle construction would include pile driving and falsework
bents. Conceptual work/demolition trestle plan sheets are included in
Appendix B and D of the WSDOT IHA application.
The proposed project would construct 1.789 acre of new impervious
surface (bridge and approaches) and would remove 1.133 acres of
existing impervious surface, with a net increase of 0.656 acre. Runoff
from the proposed project would be treated via the City of Bremerton
stormwater facilities. In addition to treating the runoff from the new
bridge, the stormwater system would treat runoff from an additional
0.81 acre of existing impervious surface, the stormwater from which is
currently discharged untreated into Sinclair Inlet.
The following is a description of the sequence of anticipated work
activities associated with the Manette Bridge replacement project.
1. Construction of Work Trestles and Falsework Towers
Separate work trestles would be constructed for the new bridge
construction and existing bridge removal processes. The south trestles
for access to the new bridge site would be constructed prior to the
installation of the north trestles for bridge removal. The work
trestles and associated falsework towers would be supported on steel
pilings with diameters of 24 to 36 in. (0.61 to 0.91 m). The
construction of the work trestles is estimated to take up to 9 months.
The work trestles and falsework towers would be in place throughout the
project duration, approximately 3 years.
The trestles would be located a few feet above the high water mark,
with the exact height determined by the contractor and work site
conditions. The trestles would be supported by steel girders attached
to the piles and the deck would be composed of timbers. The new bridge
construction work trestle would be supported by up to 360 piles and
could cover an area of up to 40,000 ft\2\ (3,716 m\2\). The bridge
removal work trestle will be supported by up to 170 piles and could
cover an area of up to 15,900 ft\2\ (1,477 m\2\). Up to 12 additional
piles may be used for project related moorage.
All piles would be installed using a vibratory hammer unless an
impact hammer is needed to drive a pile through consolidated material
or meet bearing. Currently, pile driving is scheduled to occur July 1
to August 20, 2010, and October 6, 2010, to January 31, 2011, with an
estimated 45 minutes per pile and 410 total hours of pile driving using
a vibratory hammer. Pile driving activities would occur daily two hours
after sunrise to two hours before sunset between April 1 and September
15, 2010. No pile driving will occur during nighttime hours.
Pile driving activities generate intense sound underwater, which
could potentially impact marine mammal species in the project vicinity.
For pile driving using an impact hammer, the driver consists of a heavy
hydraulic hammer that falls by gravity to drive down the piling.
Intense impulsive sounds with rapid rise time are generated with each
hammer strike. Although each impulse is short (lasts for dozens of
milliseconds), the sound pressure levels (SPLs) are extremely high and
could exceed 200 dB re 1 microPa (peak) at 1 m. The source SPLs of
impact pile driving depend on the size of the hammer, diameter of the
piles to be driven, and substrate. For the impact hammer that would be
used in the Manette Bridge replacement activities, the WSDOT used the
data from the recent Washington State Ferries impact pile driving
projects and showed that the source SPLs could be as high as 214 dB re
1 microPa (peak) at 1 m. Noises generated from impact pile driving are
broadband (contains a wide spectrum of frequency) but major energy is
concentrated between 200 1,000 Hz with less energy at higher
frequencies.
Unlike pile driving using impact hammers, vibratory pile driving is
achieved by means of a variable eccentric vibrator attached to the head
of the pile. The installation process begins by placing a choker around
the pile and lifting it into vertical position with the crane. The pile
would then be lowered into position and set in place at the mudline.
The pile would be held steady while the vibratory hammer installs the
pile to the required tip elevation. Measured noise levels for similar
projects conducted by the California Department of Transportation
(CALTRANS) and WSDOT show that source levels are around 180-195 dB re 1
microPa (peak) at 1 m. Since underwater SPLs are expressed in terms of
decibel in reference to acoustic pressure of 1 microPa, the 19 dB
difference between the source levels from impact pile driving (214 dB
re 1 microPa) and vibratory pile driving (195 dB re 1 microPa)
translates into more than three times the difference in acoustic
pressure. Therefore, vibratory pile driving is much ``quieter'' than
impact pile driving. However, because the transient sound produced by
vibratory pile driving has a longer duration than impact pile driving
pulses, it is arguable that a single batch of vibratory pile driving
noise could contain more acoustic energy than a single impact hammer
pulse in terms of sound exposure levels (SEL).
2. Barge Anchoring and Usage
Barges would be used extensively throughout the project duration to
provide access to work areas, support machinery, deliver and stage
materials, and as a collection surface for spoils, construction debris,
and materials from demolition. The actual number and dimensions of
barges to be used would be determined by the contractor and work site
conditions. However, it is estimated that up to 6 barges would be used
at one time. A typical barge dimension is approximately 290 ft (88.4 m)
in length and 50 ft (15.2 m) in width. Typical barge draft is 4 to 8 ft
(1.22 to 2.44 m) and typical freeboard is 3 to 6 ft (0.91 to 1.83 m).
Barges would be used throughout the construction period, approximately
3 years.
During working hours, barges would be attached to mooring lines,
the work trestles, or to other portions of the project area, depending
on the construction and access needs. Up to 6 temporary buoys may be
installed to moor barges during non-working hours. These buoys would be
attached to one or more anchors, which may need to be driven, or
excavated, due to hard ground and strong currents in the project area.
If the contractor chooses to deploy a dynamic barge positioning system,
it is expected that the hours the system is in use would coincide
closely with pile driving activities.
Noise produced from a moored barge is not likely to be significant
enough to affect marine mammals. However, if a dynamic positioning (DP)
system is applied to stabilize the barge, sound generated by the DP
system could be strong enough to adversely affect marine mammals in the
vicinity. The intensity of the DP system would depend on the size of
the vessel and the system output, nevertheless, its loudness is not
likely to surpass that from vibratory pile driving at the same
distances.
[[Page 13505]]
3. Construction of New Piers
Eight piers would support the new bridge, six in-water and two
upland. The existing bridge has 13 piers, nine in-water and three
upland. The total footprint of the piers would be 1,416 ft\2\ (131.6
m\2\). The footprint of the nine in-water piers supporting the existing
bridge is 8,726 ft\2\ (810.7 m\2\).
Piers 1 and 8 are the bridge abutments and are located well above
the mean high water line (MHW). Piers 2 through 7 are located below the
MLLW line. The construction of the in-water piers (2 through 7) would
take up to 18 months. The construction of the abutment piers (1 and 8)
would occur during the bridge closure period (targeted duration of 3
months). The construction of each would include excavation of up to 3
shafts to support each pier, concrete pouring of each shaft, and
construction of piers on top of new shafts.
Shaft casings would be installed and the shafts will be excavated
using equipment positioned on the work trestles or barges.
To create a drilled shaft, a steel casing approximately 6 to 10 ft
(1.8 to 3 m) in diameter is driven into the substrate using a vibratory
hammer, and the material inside the casing is excavated using an auger
or a clamshell dredge. During excavation a premixed bentonite or
synthetic polymer slurry is sometimes added to stabilize the walls of
the shaft. Spoils from shaft excavation would be placed in a large
steel containment box located on a barge or on the work trestle for
offsite transport. During the drilling, polymer slurry is typically
placed into the hole to keep side walls of the shaft from caving.
After completion of the excavation, a steel reinforcing cage is
placed into the hole to specified elevations. Concrete is then pumped
into the hole using a tremie tube placed at the bottom of the
excavation. As concrete is placed the tremie tube is raised but is
maintained within the concrete. As the concrete is pumped into the
hole, the slurry is displaced upward and removed from the top concrete
using a vacuum hose. The slurry is pumped from the hole into large
tanks located on the work trestle or on a barge, which is either
recycled for use in the next shaft or transported off site. This
procedure would be used on all shafts at each pier.
After shafts are completed, pre-cast concrete, stay-in-place forms
would be stacked on top of the shafts up to the crossbeam elevation. A
steel reinforcing cage would be placed inside the concrete forms and
the columns would be filled with concrete. A pre-cast concrete
crossbeam or a cast-in-place crossbeam, or some combination of both
would be constructed on top of the columns. Girders would be fabricated
off site and would be shipped to the site on barges. The girders would
then be placed on the piers and falsework towers between piers 2 and 7.
After completion of the girder placement and casting of diaphragms
connecting the girders, post-tensioning strands would be placed into
ducts cast in the girders. The post-tensioning strands will then be
stressed. The roadway deck would then be formed and cast between piers
2 and 7.
Noise levels and characteristics generated by coastal construction
work related to excavation and drilling are not well studied. Studies
on construction of offshore oil industry facilities in the Arctic
provide some insights on the noise levels and characteristics from
marine dredging. Dredging and drilling noises are broadband with most
of their energy concentrated in the lower range of the frequency
spectrum, between 20 1,000 Hz. Nevertheless, these noises are expected
to be much lower than those from vibratory pile driving at source
locations.
4. Installation of Girders and Decking
Girders and decking would be installed using the work trestles,
falsework towers, and cranes deployed on work barges. The roadway deck
would be made of concrete and would be poured in place. This work is
expected to take 3 to 4 months. Noises from this session of work are
similar to those mentioned above.
5. Reconfiguration of Abutments and Roadway Approaches
The existing bridge abutments would be removed, along with the
associated retaining walls. New retaining walls and abutments would be
constructed. These activities, and associated construction access would
require the temporary disturbance of 0.75 acre of land, of which 0.15
acre are vegetated and permanent removal of 0.15 acre of vegetation.
This work, all in upland areas, includes 2000 cubic yards of fill. Once
the abutments are complete, the new bridge approach roadways will be
constructed. Disturbed areas on the east shore of the Port Washington
Narrows would be restored with a mix of native trees and shrubs
including marine riparian vegetation and shoreline enhancement. Noises
from this session of work are similar to those mentioned above
associated with pier construction.
6. Demolition of Existing Bridge
The demolition of the existing bridge would occur in phases over a
period of 18 months. After the central portion of the new bridge is
constructed, the outermost spans and abutments of the existing bridge
would be demolished. Once the new abutments and outer spans are
constructed, the demolition of the remainder of the existing bridge
will proceed. Conceptual demolition plan sheets are included in
Appendix D of the WSDOT IHA application.
The bridge structure above the water line would be cut into
manageable sections, using conventional concrete and metal cutting
tools, or a wire saw, and placed on barges for transport to approved
waste or recycling sites. The portions of the piers below the water
line would be cut into pieces using a wire saw. All slurry from wire
cutting operations above the water line would be contained and removed.
All slurry from wire cutting operations below the water line would be
dispersed by the current. Piers would be cut off at the ground level
except for one, Pier 4. Pier 4 was built up to encapsulate original
creosote treated timbers. Complete removal of the pier is not feasible
and if it is cut at the ground level, many creosote treated timbers may
be exposed. To minimize the risk of contamination, Pier 4 would be cut
two feet above ground level.
No information is available regarding noises generated from bridge
structure cutting. However, since the cutting for bridge structures
would be done above the water line, noise transmitted into the water
via the structure is not expected to be significant.
7. Removal of Falsework Towers and Work Trestles
Once the demolition of the existing bridge is complete, the
falsework towers and work trestles would be removed. Decking and
girders would be placed on barges for transportation off-site. Piles
would be removed using vibratory hammers, based on barges. The removal
of the falsework towers and work trestles is expected to occur over 4
to 6 months.
Vibratory extraction is a common method for removing steel piling.
The pile is unseated from the sediments by engaging the hammer and
slowly lifting up on the hammer with the aid of the crane. Once
unseated, the crane would continue to raise the hammer and pull the
pile from the sediment. When the pile is released from the sediment,
the vibratory hammer is disengaged and the pile is pulled from the
water and placed on a barge for transfer upland.
[[Page 13506]]
Noise levels and characteristics from pile extraction using a
vibratory hammer are not well studied, however, the intensity of the
noise is expected to be higher than the intensity of noise from pile
installation using the same vibratory hammer.
The Manette Bridge Replacement project is scheduled to begin in
June 2010 and continue for up to three years. No in-water activities
will be planned between March 1 and June 14 in water bellow the
ordinary high water line.
Description of Marine Mammals in the Area of the Specified Activity
Six marine mammal species/stocks occur in the area where the
proposed Manette Bridge replacement work is planned. These six species/
stocks are: Pacific harbor seal (Phoca vitulina richardsi), California
sea lion (Zalophus californianus), Steller sea lion (Eumetopias
ubatus), transient and Southern Resident killer whales (Orcinus orca),
and gray whale (Eschrichtius robustus). All these marine mammals have
been observed in southern Puget Sound during certain periods of the
year and may occur in Sinclair Inlet, Port Washington Narrows and Dyes
Inlet, although direct observation in the vicinity of the Manette
Bridge may not be documented. General information on these marine
mammal species can be found in Caretta et al. (2007), which is
available at the following URL: http://www.nmfs.noaa.gov/pr/pdfs/sars/po2008.pdf. Refer to that document for information on these species.
To further gather information on the occurrence of these marine
mammal species in the vicinity of the proposed project area, the WSDOT
contracted ten surveys between the months of July 2006 and January
2007. This time period was chosen for sampling because it represents
the time period when most in-water work activities would occur. Two
pinniped species and zero cetaceans were observed. Thirty four harbor
seals, one California sea lion and one unidentified pinniped, likely a
California sea lion, were observed over the six month period. In
general, cetacean observations are infrequent in the Puget Sound
(Calambokidis and Baird 1994, Jefferies 2007). During ten surveys for
marine mammals in Sinclair Inlet and Port Washington Narrows between
July 2006 and January 2007, no cetaceans were observed. No marine
mammals were observed during two of the ten surveys. Detailed results
of the surveys are provided in a final report, which is included in
Appendix E of the WSDOT IHA application.
Additional information on these species, particularly in relation
to their occurrence in the proposed project area, is provided below.
1. Harbor Seal
Three distinct harbor seal stocks occur along the west coast of the
continental U.S., the Washington inland waters stock, Oregon/Washington
coastal stock, and California stock (Caretta et al. 2009). The
Washington inland waters stock of the Pacific harbor seal is
distributed in inland waters including Hood Canal, Puget Sound, and the
Strait of Juan de Fuca out to Cape Flattery (Caretta et al. 2007), and
is expected to occur in the proposed project area.
Harbor seal is the most common pinniped and the only marine mammal
species that breeds in the inland marine waters of Washington
(Calambokidis and Baird 1994). Pupping and molting typically occurs
between April and August.
Individual harbor seals are frequently observed in the Port
Washington Narrows, Sinclair Inlet and Dyes Inlet. Harbor seals were
observed during eight of ten surveys between July 2006 and January
2007. No more than six individuals were observed during any one survey
period. There are no documented harbor seal haul-out areas within 3
miles (4.8 km) of the Manette Bridge. One harbor seal haul-out
estimated at less than 100 animals is documented in Dyes Inlet west of
the Manette Bridge. These animals must pass through the Port Washington
Narrows to gain access to Sinclair Inlet and the greater Puget Sound
basin.
In 1999, Jefferies et al. (2003) recorded a mean count of 9,550
harbor seals in Washington's inland marine waters. The estimated
population for this stock is approximately 14,612 harbor seals with a
correction factor to account for animals in the water which were missed
during the aerial surveys (Calambokidis and Baird 1994; Carretta et al.
2009). From 1991 to 1996, counts of harbor seals in Washington State
have increased at an annual rate of 10% (Jefferies et al. 1997). Harbor
seals are not considered to be ``depleted'' under the MMPA or listed as
``threatened'' or ``endangered'' under the Endangered Species Act
(ESA).
2. California Sea Lion
California sea lions occur throughout the Pacific Rim and are
separated into three subspecies, of which only one occurs in western
North America (Caretta et al. 2009). The subspecies is further
separated into three stocks, the United States (US) stock, the Western
Baja California stock and the Gulf of California stock (Caretta et al.
2009).
The U.S. stock of California sea lion is expected to occur in the
vicinity of the proposed project area. They breed in California and
southern Oregon between May and July, but not in Washington. Pupping
occurs on the breeding ground, typically one month prior to mating. Sea
lions are typically observed in Washington between August and April,
after they have dispersed from breeding colonies.
There are no documented California sea lion haul outs within 3
miles (4.8 km) of the Manette Bridge. Two California sea lion haul-outs
estimated at less than 10 animals are documented on bouys in Rich
Passage approximately 4 miles (6.4 km) to the east. Individuals are
infrequently observed in the Port Washington Narrows, Sinclair Inlet
and Dyes Inlet. One California sea lion was observed during one of ten
surveys between July 2006 and January 2007. An unidentified pinniped
was also recorded during one survey and is believed to be a California
sea lion, although positive identification was not possible.
Population estimates are calculated by conducting pup counts.
Because California sea lions do not breed in Washington, accurate
estimates of the non-breeding population in Washington do not exist.
Estimates from the 1980s suggest the population size was just under
3,000 by the mid-1980s (Bigg 1985; Gearin et al. 1986). In the 1990s,
the number of sea lions in Washington appears to have either stabilized
or decreased (Gearin et al. 1988; Calambokidis and Baird 1994). The
entire population of the US stock of California sea lion is estimated
to be approximately 238,000 (Carretta et al. 2009). The California sea
lions are not considered to be ``depleted'' under the MMPA or listed as
``threatened'' or ``endangered'' under the ESA.
3. Steller Sea Lion
Steller sea lion occur along the north Pacific Rim with the
population center in the Gulf of Alaska and the Aleutian Island chain.
This species is separated into two stocks, the eastern and western
stocks. The Eastern stock ranges from southeast Alaska south to
California (Loughlin et al. 1984). The Eastern stock breeds in Alaska,
British Columbia, Oregon and California, but does not have breeding
rookeries in Washington. Breeding typically occurs from May to July.
Pupping occurs within days of returning to the breeding colony.
Individuals, especially adult males and juveniles, disperse widely
and travel great distances outside of the
[[Page 13507]]
breeding season, including waters off and within Washington State.
Individual Steller sea lions typically return to breeding grounds in
May, although in 2007 and 2008 two to six individual Steller sea lions
remained all summer near Nisqually (southern Puget Sound near Olympia)
on the Toliva Shoals and Nisqually buoys. There was also one Steller
sea lion observed at Point Defiance (near Tacoma, Washington) in July
2008. Furthermore, reports of Steller sea lions on the North Vashon,
Manchester and Bainbridge Island bouys increased in winter 2007 - 2008
and spring 2008 although there are no estimates of individual numbers
for these reports (WSDOT, 2009). According to Jefferies (2008) there
are also records from the 1990's of 200 - 300 Steller sea lions using
Navy floats at the Fox Island Acoustic Range. The majority of Steller
sea lions are observed in the north Puget Sound and Strait of Juan de
Fuca, although Steller sea lions are regularly observed at three
haulout sites in central and southern Puget Sound. The nearest site,
Shilshole Bay, is on the east side of the Puget Sound, adjacent to the
city of Seattle approximately 12 miles (19.3 km) from the Manette
Bridge.
Population estimates are calculated by conducting pup counts.
Because Steller sea lions do not breed in Washington, accurate
estimates of the non-breeding population in Washington do not exist.
Using the most recent 2005 pup counts from aerial surveys across the
range of the eastern stock, the total population of the eastern stock
of Steller sea lion is estimated to be between 46,000 and 58,000
(Pitcher et al. 2007; Angliss and Allen 2009). The eastern stock of
Steller sea lion is listed as ``threatened'' under the ESA, and is
designated as a ``depleted'' stock under the MMPA.
4. Gray Whale
The North Pacific gray whale stock is divided into two distinct
stocks: the eastern North Pacific and western North Pacific stocks
(Rice et al. 1984; Angliss and Allen 2009). The eastern North Pacific
stock ranges from Alaska, where they summer, to Baja California, where
they migrate to calve in the winter.
Gray whales occur frequently off the coast of Washington during
their southerly migration in November and December, and northern
migration from March through May (Rugh et al. 2001, Rice et al. 1984).
Gray whales are observed in Washington inland waters regularly between
the months of January and September, with peaks between March and May.
The average tenure within Washington inland waters is 47 days and the
longest stay was 112 days (Cascadia Research Collective, unpub.
report). Gray whales are reported in Sinclair Inlet, Port Washington
Narrows or Dyes Inlet during migration. Between 2001 and 2007, gray
whale sightings were reported during three of the years (Orca Network
2007). Reports occurred in April 2002, February, March and May 2005,
and March and April 2007. The May 2005 observation was a stranding
mortality at the Kitsap Naval Base in Bremerton (Orca Network 2007).
Systematic counts of the eastern North Pacific gray whales have
been conducted by shore-based observers during their southbound
migration along the central California coast. The most recent abundance
estimate is based on counts made during the 2001-02 seasons. Based on
the data, the abundance estimate for this stock of gray whale is 18,178
individuals (Angliss and Allen 2009). The eastern North Pacific gray
whale was removed from the ESA-list in 1994, due to steady increases in
population abundance. Therefore, it is not considered ``endangered'' or
``threatened'' under the ESA.
5. Killer Whale
Two distinct forms, or ecotypes, of killer whales ``residents'' and
``transients'' are found in the greater Puget Sound. These two ecotypes
are different populations of killer whales that vary in morphology,
ecology, behavior, and genetics. Both ecotypes of killer whales are not
known to intermix with one another.
Resident Killer Whales are noticeably different from both transient
and offshore forms. The dorsal fin is rounded at the tip and falcate
(curved and tapering). Resident whales have a variety of saddle patch
pigmentations with five different patterns recognized. They've been
sighted from California to Alaska. Resident whales primarily eat fish.
The ``resident'' population that could occur in the proposed
project area is the Southern Resident killer whale (SRKW). This
population contains three pods (or stable family-related groups) J pod,
K pod, and L pod and is considered a stock under the MMPA. Their range
during the spring, summer, and fall includes the inland waterways of
Puget Sound, Strait of Juan de Fuca, and Southern Georgia Strait. Their
occurrence in the coastal waters off Oregon, Washington, Vancouver
Island, and more recently off the coast of central California in the
south and off the Queen Charlotte Islands to the north has been
documented. Little is known about the winter movements and range of the
Southern Resident stock. Resident killer whales feed exclusively on
fish such as salmon (Calambokidis and Baird 1994).
Southern resident killer whale presence is possible but unlikely in
the proposed project area. They were last seen in the vicinity of the
proposed project area in 1997. Nineteen members of L pod (subpod L-25)
arrived on October 21, 1997 and stayed in Dyes Inlet for 30 days (WSDOT
2009). A fall chum run has been suggested as the reason for the
extended stay. The only access to Sinclair Inlet is to the north (Agate
Passage) or south (Rich Passage) of Bainbridge Island.
The Southern Resident killer whale population is currently
estimated at about 86 whales (Carretta et al. 2009), a decline from its
estimated historical level of about 200 during the mid- to late 1800s.
Beginning in about 1967, the live-capture fishery for oceanarium
display removed an estimated 47 whales and caused an immediate decline
in SRKW numbers. The population fell an estimated 30% to about 67
whales by 1971. By 2003, the population increased to 83 whales. Due to
its small population size, NMFS listed this segment of the population
as endangered under the Endangered Species Act (ESA). This population
is also listed as depleted under the MMPA.
Transient killer whales occur throughout the eastern North Pacific,
primarily in coastal waters. Individual transient killer whales have
been documented as traveling great distances, reflecting a large home
range. The dorsal fin of transient whales tends to be more erect
(straighter at the tip) than those of resident whales. Saddle patch
pigmentation of transient killer whales is restricted to two patterns.
Pod structure is small (e.g., fewer than 10 whales) and dynamic in
nature. Transient killer whales feed exclusively on other marine
mammals such as dolphins, sea lions, and seals.
The transient killer whale population that could occur in the
proposed project area is the West Coast transient stock. It is a trans-
boundary stock, which includes killer whales from British Columbia. The
presence of this killer whale population in the south Puget Sound is
considered rare. In 2008, there were only two reports of transient orca
whales in the south Puget Sound. One of these reports occurred in
January just east of Maury Island and the other report of transients
occurred in August in the Tacoma narrows (WSDOT 2009).
Preliminary analysis of photographic data results in a minimum of
314 killer whales belonging to the West Coast transient stock (Angliss
and Allen
[[Page 13508]]
2009). This number is also considered the minimum population estimate
of the population since no correction factor is available to provide a
best estimate of the population. At present, reliable data on trends in
population abundance for the West Coast transient stock of killer
whales are unavailable (Angliss and Allen 2009). This stock of killer
whale is not designated as ``depleted'' under the MMPA nor is it listed
under the ESA.
Potential Effects on Marine Mammals and Their Habitat
Anticipated impacts resulting from the Manette Bridge Replacement
project include disturbance from increased human presence and marine
traffic if marine mammals are in the vicinity of the proposed project
area, Level B harassment by noises generated from the construction work
such as pile driving and dredging activities, and the effect of the new
bridge and stormwater system on water quality.
1. Impacts from Anthropogenic Noise
Marine mammals exposed to high intensity sound repeatedly or for
prolonged periods can experience hearing threshold shift (TS), which is
the loss of hearing sensitivity at certain frequency ranges (Kastak et
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be
permanent (PTS), in which case the loss of hearing sensitivity is
unrecoverable, or temporary (TTS), in which case the animal's hearing
threshold will recover over time (Southall et al. 2007). Since marine
mammals depend on acoustic cues for vital biological functions, such as
orientation, communication, finding prey, and avoiding predators,
marine mammals that suffer from PTS or TTS will have reduced fitness in
survival and reproduction, either permanently or temporarily. Repeated
noise exposure that leads to TTS could cause PTS.
Measured source levels from impact pile driving can be as high as
214 dB re 1 microPa\2\ 1 m. Although no marine mammals have been shown
to experience TTS or PTS as a result of being exposed to pile driving
activities, experiments on a bottlenose dolphin (Tursiops truncates)
and beluga whale (Delphinapterus leucas) showed that exposure to a
single watergun impulse at a received level of 207 kPa (or 30 psi)
peak-to-peak (p-p), which is equivalent to 228 dB re 1 microPa (p-p),
resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz,
respectively. Thresholds returned to within 2 dB of the pre-exposure
level within 4 minutes of the exposure (Finneran et al. 2002). No TTS
was observed in the bottlenose dolphin. Although the source level of
pile driving from one hammer strike is expected to be much lower than
the single watergun impulse cited here, animals being exposed for a
prolonged period to repeated hammer strikes could received more noise
exposure in terms of SEL than from the single watergun impulse
(estimated at 188 dB re 1 microPa\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 noise
levels for prolonged period of time. Current NMFS standards for
preventing injury from PTS and TTS is to require shutdown or power-down
of noise sources when a cetacean species is detected within the
isopleths corresponding to SPL at received levels equal to or higher
than 180 dB re 1 microPa (rms), or a pinniped species at 190 dB re 1
microPa (rms). Based on the best scientific information available,
these SPLs are far below the threshold that could cause TTS or the
onset of PTS. Certain mitigation measures proposed by the WSDOT,
discussed below, can effectively prevent the onset of TS in marine
mammals, by either reducing the source levels (using an air bubble
curtain system) and by shut-down and power down procedures for pile
driving.
In addition, chronic exposure to excessive, though not high-
intensity, noise could cause masking at particular frequencies for
marine mammals that utilize sound for vital biological functions.
Masking can interfere with detection of acoustic signals such as
communication calls, echolocation sounds, and environmental sounds
important to marine mammals. Therefore, like TS, marine mammals whose
acoustical sensors or environment are being masked are also impaired
from maximizing their performance fitness in survival and reproduction.
Masking occurs at the frequency band which the animals utilize.
Therefore, since noise generated from the proposed bridge replacement
activities, such as pile driving, vessel traffic, and dredging, is
mostly concentrated at low frequency ranges, it may have less effect on
high frequency echolocation sounds by killer whales. However, lower
frequency man-made noises are more likely to affect detection of
communication calls and other potentially important natural sounds such
as surf and prey noise. It may also affect communication signals when
they occur near the noise band and thus reduce the communication space
of animals (e.g., Clark et al. 2009) and cause increased stress levels
(e.g., Foote et al. 2004; Holt et al. 2009).
Unlike TS, masking impacts the species at population, community, or
even ecosystem levels (instead of individual levels caused by TS).
Masking affects both senders and receivers of the signals and has long-
term chronic effects on marine mammal species and populations. Recent
science suggests that low frequency ambient sound levels have increased
by as much as 20 dB (more than 3 times in terms of SPL) in the world's
ocean from pre-industrial periods, and most of these increases are from
distant shipping (Hildebrand 2009). All anthropogenic noise sources,
such as those from vessels traffic, pile driving, and dredging
activities, contribute to the elevated ambient noise levels, thus
intensify masking.
Nevertheless, the sum of noise from the proposed bridge replacement
is confined in an area of inland waters that is bounded by landmass,
therefore, the noise generated is not expected to contribute to
increased ocean ambient noise.
Finally, exposure of marine mammals to certain sounds could lead to
behavioral disturbance (Richardson et al. 1995), such as: changing
durations of surfacing and dives, number of blows per surfacing, or
moving direction and/or speed; reduced/increased vocal activities,
changing/cessation of certain behavioral activities (such as
socializing or feeding); visible startle response or aggressive
behavior (such as tail/fluke slapping or jaw clapping), avoidance of
areas where noise sources are located, and/or flight responses (e.g.,
pinnipeds flushing into water from haulouts or rookeries).
The biological significance of many of these behavioral
disturbances is difficult to predict, especially if the detected
disturbances appear minor. However, the consequences of behavioral
modification could be expected to be biologically significant if the
change affects growth, survival, and reproduction. Some of these
significant behavioral modifications include:
Drastic change in diving/surfacing patterns (such as those
thought to be causing beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Habitat abandonment due to loss of desirable acoustic
environment; and
Cease feeding or social interaction.
For example, at the Guerreo Negro Lagoon in Baja California,
Mexico, which is one of the important breeding grounds for Pacific gray
whales, shipping and dredging associated with a salt works may have
induced gray
[[Page 13509]]
whales to abandon the area through most of the 1960s (Bryant et al.
1984). After these activities stopped, the lagoon was reoccupied, first
by single whales and later by cow-calf pairs.
The onset of behavioral disturbance from anthropogenic noise
depends on both external factors (characteristics of noise sources and
their paths) and the receiving animals (hearing, motivation,
experience, demography) and is also difficult to predict (Southall et
al. 2007).
The proposed project area is not believed to be a prime habitat for
marine mammals, nor is it considered an area frequented by marine
mammals. Therefore, behavioral disturbances that could result from
anthropogenic construction noise associated with bridge replacement are
expected to affect only a small number of marine mammals on an
infrequent basis.
Currently NMFS uses 160 dB re 1 microPa at received level for
impulse noises (such as impact pile driving) as the onset of marine
mammal behavioral harassment, and 120 dB re 1 microPa for continued
noises (vibratory pile driving and dredging).
As far as airborne noise is concerned, as mentioned before, the
nearest pinniped haulout (harbor seal) is in Dyes Inlet, which is
approximately 3 miles (4.8 km) west of the proposed project area. NMFS
does not expect that airborne noise from pile driving would reach
harassment levels at this distance.
2. Impacts from Presence of Human Activities
In addition to noise induced disturbances and harassment, the
increased human presence and vessel traffic associated with the bridge
replacement construction is also expected to have adverse impacts to
marine mammals in the vicinity of the proposed project.
Some of the expected impacts could result from work trestles and
barge anchoring. The construction and demolition work trestles would
cover up to 55,900 square feet (5,193 m\2\) of the Port Washington
Narrows throughout the construction period, a duration of approximately
three years, although neither trestle would be in place for that entire
period. The size of these trestles has been reduced to the greatest
extent practicable according to WSDOT. The demolition trestle would be
installed during the in-water work window immediately prior to
initiation of bridge demolition activities occurring from this trestle
and both trestles would be removed as soon as practicable following the
completion of construction and demolition activities. Barge anchoring
would occur adjacent to the construction and demolition work trestles
creating a passage the width of the shipping channel between the Port
Washington Narrows and Sinclair Inlet. Killer whales, if they happen to
be present in the vicinity of the area, could become confined by
psychological barriers such as nets or low walls that they can
physically cross, but for unknown reasons do not. Such was the case in
1994 in Barnes Lake near Ketchikan, Alaska, when 10 killer whales
entered following salmon but then refused to leave until human
intervention chased them out of the lake (Anonymous 1995; Bain 1995).
In 1997, 19 members of the L pod of the Southern Resident killer whales
entered Dyes Inlet near Bremerton, Washington, which is approximately 3
miles (4.8 km) west of the proposed project area and is surrounded by
urban and residential development, and stayed there for nearly 30 days
(Wiles 2004; NMFS 2008). The long length of residence of killer whales
in this area was highly unusual and the reason is unclear, but may have
been related to food abundance since it was coincidence to a strong run
of chum salmon into Chico Creek between late October and November, or a
reluctance by the whales to depart the inlet because of the physical
presence of a bridge crossing the Port Washington Narrows and
associated road noise (Wiles 2004; NMFS 2008). The work trestles and
barges may present a similar situation that would discourage or prevent
killer whales from exiting Dyes Inlet or Port Washington Narrows and
returning to more open water if the whales happen to enter the inlet.
However, as mentioned before, the occurrence of killer whales in the
vicinity of proposed project area is not frequent.
3. Impacts from Water Quality
Marine mammals are especially vulnerable to contaminants because
their apex trophic levels in the ecosystem promote bioaccumulation of
contaminants. Water quality conditions will generally improve as a
result of the construction of stormwater treatment facilities
associated with the project. Currently, stormwater from the existing
roadway and bridge is discharged, untreated, into the Port Washington
Narrows. The WSDOT states that post project, all stormwater leaving the
bridge would receive treatment by the city of Bremerton. Therefore, the
impact from water quality is expected to be reduced as the result of
the proposed bridge replacement project.
Proposed Mitigation Measures
In order to issue an incidental take authorization under Section
101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods
of taking pursuant to such activity, and other means of effecting the
least practicable adverse impact on such species or stock and its
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance, and on the availability of such species
or stock for taking for certain subsistence uses.
For the proposed Manette Bridge replacement project, the WSDOT
worked with NMFS and proposed the following mitigation measures to
minimize the potential impacts to marine mammals in the project
vicinity as a result of the construction activities.
1. Overall Construction Activities
The WSDOT states that all its construction is performed in
accordance with the current WSDOT Standard Specifications for Road,
Bridge, and Municipal Construction. Special Provisions contained in
contracts are used in conjunction with, and supersede, any conflicting
provisions of the Standard Specifications.
WSDOT activities are subject to state and local permit conditions.
WSDOT states that it uses the best guidance available (e.g., best
management practices and conservation measures) to accomplish the
necessary work while avoiding and minimizing environmental impacts to
the greatest extent possible.
The WSDOT contractor is expected to be responsible for the
preparation of a Spill Prevention, Control, and Countermeasures plan to
be used for the duration of the project. The plan would be submitted to
the WSDOT Project Engineer prior to the commencement of any
construction activities. A copy of the plan with any updates will be
maintained at the work site by the contractor. A detailed discussion of
the plan is provided in the WSDOT's IHA application.
2. Equipment Noise Standards
To mitigate noise levels and, therefore, impacts to marine mammals,
all the construction equipment would comply with applicable equipment
noise standards of the U.S. Environmental Protection Agency, and all
construction equipment will have noise control devices no less
effective than those provided on the original equipment.
3. Timing Windows
Timing restrictions are used to avoid construction activities that
generate relatively intense underwater noises
[[Page 13510]]
(i.e., pile driving, dredging, and dynamic positioning) when ESA-listed
species are most likely to be present. If an ESA-listed marine mammal
species is detected in the vicinity of the project area, pile driving
and dredging operations will be halted and stationing construction
vessels will turn off dynamic positioning systems. WSDOT states that it
will comply with all in-water timing restrictions as determined through
the MMPA take authorization. Pile driving activities would only be
conducted during daylight hours. If the safety zone (see below) is
obscured by fog or poor lighting conditions, impact pile driving will
not be initiated until the entire safety zone is visible. In addition,
no in-water work would be conducted between March 1 and June 14 in
water below the ordinary high water line.
4. Establishment of Zones of Safety and Influence
For impact pile driving, the safety zones are defined as the areas
where received SPLs from noise source exceed 180 dB re 1 microPa (rms)
for cetaceans or 190 dB re 1 microPa (rms) for pinnipeds. Repeated and
prolonged exposure to SPLs above these values may cause TTS to
cetaceans and pinnipeds, respectively. The radii of the safety zones
would be determined through empirical measurements of acoustic data.
Prior to acquiring acoustic data, the safety zones shall be established
based on the worst-case scenario measured from impact pile driving of
36-inch (0.91 m) steel pile conducted elsewhere, such as the Anacortes
or Mukiteo ferry terminals. Acoustic measurements indicate that source
levels are approximately 201 dB re 1 microPa (rms) at 10 m for both
pile driving activities for Anacortes and Mukiteo ferry terminal
constructions when the 36-inch (0.91 m) piles were hammered in
(Laughlin 2007; Sexton 2007). Approximation of the received levels of
180 and 190 dB re 1 microPa (rms) by using an acoustic propagation
spreading model between spherical and cylindrical propagation,
TL = 15log(RRL/RSL),
where TL is the transmission loss (in dB), RRL is the distance at
received levels (either 180 or 190 dB), and RSL is the
distance (10 m) at source level (201 dB). The results show that the
distances for received levels 180 and 190 dB re 1 microPa (rms) are
approximately 251 m and 54 m, respectively. NMFS expects that the
modeled safety zones are reasonably conservative as the propagation
model does not take into consideration other transmission loss factors
such as sound absorption in the water column.
Once impact pile driving begins, NMFS requires that the contractor
adjust the size of the safety zones based on actual measurements of
SPLs at various distances to determine the most conservative (the
largest) safety zones at which the received levels are 180 and 190 dB
re 1 microPa (rms).
Since the source levels for vibratory pile driving are expected to
be under 180 dB re 1 microPa (rms) at 10 m, no safety zones would be
established for vibratory pile driving.
In addition, WSDOT and its contractor shall establish zones of
influence (ZOIs) at received levels of 160 and 120 dB re 1 microPa
(rms) for impulse noise (noise from impact pile driving) and non-
impulse noise (such as noise from vibratory pile driving and dynamic
positioning system), respectively. These SPLs are expected to cause
Level B behavioral harassment to marine mammals. The model based
approximation for the distance at 160 dB received level is 5,412 m from
pile driving based on the most conservative measurements from the
Anacortes or Mukiteo ferry terminal construction (201 dB re 1 microPa
(rms) at 10 m; Laughlin 2007; Sexton 2007), using the same spreading
model discussed above. Once impact pile driving starts, the contractor
shall conduct empirical acoustic measurements to determine the most
conservative distance (the largest distance from the pile) where the
received levels begin to fall below 160 dB re 1 microPa (rms).
As far as non-pulse noises are concerned, for which the Level B
behavioral harassment is set at a received level of 120 dB re 1
microPa, no simple modeling is available to approximate the distance
(though direct calculation using the spreading model puts the 120 dB
received level at 100 km, this simple approximation no longer works at
this long distance due to range-dependent propagation involving complex
sound propagation behavior that cannot be ignored). NMFS uses the
empirical underwater acoustic measurements from vibratory pile driving
of 42 48-inch (1.06 1.22 m) diameter piles at the San Francisco-Oakland
Bay Bridge construction as a model and expects that the distance at a
received level of 120 dB is less than 1,900 m from the pile (CALTRANS
2009). Likewise, WSDOT and its contractor shall conduct empirical
acoustic measurements to determine the actual distance of 120 dB re 1
microPa (rms) from the pile.
All safety and influence zones shall be monitored for marine
mammals prior to and during construction activities. Please refer to
the Monitoring and Reporting Measures section for a detailed
description of monitoring measures.
5. Shutdown Measures
To prevent marine mammals from exposure to intense sounds that
could potentially lead to TTS (i.e., received levels above 180 dB and
190 dB re 1 microPa (rms) for cetaceans and pinnipeds, respectively),
no impact pile driving shall be initiated when marine mammals are
detected within these safety zones. In addition, during impact driving,
when a marine mammal is detected within the respective safety zones or
is about to enter the safety zones, impact pile driving shall be halted
and shall not be resumed until the animal is seen to leave the safety
zone on its own, or 30 minutes has elapsed until the animal is last
seen.
WSDOT also agrees that pile driving and dredging activities would
be suspended when ESA-listed marine mammals (Steller sea lion and
killer whale) are detected within the zone of behavioral harassment
(160 dB re 1 microPa for impulse sources and 120 dB re 1 microPa for
non-impulse sources) and that all vessels' dynamic positioning systems
would be turned off. Therefore, no take of ESA-listed marine mammal
species or stocks is expected.
6. ``Soft Start'' Impact Pile Driving or Ramp-up
Although marine mammals will be protected from Level A harassment
by establishment of an air-bubble curtain during impact pile driving
and marine mammal observers monitoring a safety zone, monitoring may
not be 100 percent effective at all times in locating marine mammals.
Therefore, WSDOT proposes to use a 'soft-start' technique at the
beginning of each day's in-water pile driving activities or if pile
driving has ceased for more than one hour to allow any marine mammal
that may be in the immediate area to leave before pile driving reaches
full energy.
For vibratory pile driving, the soft start requires contractors to
initiate noise from vibratory hammers for 15 seconds at reduced energy
followed by a one minute waiting period. The procedure will be repeated
two additional times. If an impact hammer is used on a pile greater
than 10 inches in diameter, contractors will be required to provide an
initial set of three strikes from the impact hammer at 40 percent
energy, followed by a one minute waiting period, then two subsequent 3-
strike sets. This should expose fewer animals to loud sounds both
underwater and above water noise. This would also ensure that, although
not expected, any
[[Page 13511]]
pinnipeds and cetaceans that are missed during safety zone monitoring
will not be injured.
7. Sound Attenuation Measures
Specific to pile driving, the following mitigation measures are
proposed by WSDOT to reduce impacts to marine mammals to the greatest
extent practicable.
All steel piles would be installed using a vibratory hammer until
an impact hammer is needed for bearing or if a pile encounters
consolidated material. If vibratory installation is not possible due to
the substrate, an impact pile driver would be used. An air bubble
curtain(s) will be employed during impact installation of all steel
piles. Detailed description and specification of the air bubble curtain
system is provided in Appendix C of the WSDOT's IHA application.
WSDOT will provide bubble curtain performance criteria to the
contractor, which include:
Piling shall be completely engulfed in bubbles over the
full depth of the water column at all times when an impact pile driver
is in use.
The lowest bubble ring shall be in contact with the mud
line for the full circumference of the ring. The weights attached to
the bottom ring shall ensure complete mud line contact. No parts of the
ring or other objects shall prevent the full mud line contact.
Bubblers shall be constructed of minimum 2-inch (5.1-cm)
inside diameter aluminum pipe with 1/16-inch (0.16-cm) diameter bubble
release holes in four rows with 3/4-inch (1.9-cm) spacing in the radial
and axial directions. Bubblers shall be durable enough to withstand
repeated deployment during pile driving and shall be constructed to
facilitate underwater setup, knockdown, and reuse on the next pile.
One or more compressors shall be provided to supply air in
sufficient volume and pressure to self-purge water from the bubblers
and maintain the required bubble flux for the duration of pile driving.
Compressors shall be of a type that prevents the introduction of oil or
fine oil mist by the compressed air into the water. If there is
presence of oil film or sheen on the water surface in the vicinity of
the operating bubbler, the contractor shall immediately stop work until
the source of oil film or sheen is identified and corrected.
The system shall provide a bubble flux of 3.0 cubic meters
(m3) per minute per linear meter of pipe in each layer (32.91 cubic
feet, or 0.93 m3, per minute per linear foot of pipe in each layer).
The total volume of air per layer is the product of the bubble flux and
the circumference of the ring:
Vt=3.0 m\3\/min/m x Circum of the aeration ring in meters.
or
Vt=32.91 ft\3\/min/ft x Circum of the aeration ring in meters.
The bubble ring manifold shall incorporate a shut off
valve, flow meter, and a throttling globe valve with a pressure gauge
for each bubble ring supply.
Prior to first use of the bubble curtain during pile
driving, the fully-assembled system shall be test-operated to
demonstrate proper function and to train personnel in the proper
balancing of the air flow to the bubblers. The test shall also confirm
the calculated pressures and flow rates at each manifold ring. The
Contractor shall submit an inspection/performance report to WSDOT
within 72 hours following the performance test.
The WSDOT Office of Air Quality and Noise has prepared a
noise monitoring plan for the Manette Bridge Replacement Project
(Appendix H). To comply with the provisions of the plan, the State will
conduct hydroacoustic monitoring during construction to evaluate in
water noise levels.
8. Ensure Regulation Compliance
Finally, WSDOT policy and construction administration practice is
to have a WSDOT inspector on site during construction. The role of the
inspector is to ensure contract compliance. The inspector and the
contractor each have a copy of the Contract Plans and Specifications on
site and are aware of all requirements. The inspector is also trained
in environmental provisions and compliance.
NMFS has carefully evaluated the applicant's proposed mitigation
measures and considered a range of other measures in the context of
ensuring that NMFS prescribes the means of effecting the least
practicable adverse impact on the affected marine mammal species and
stocks and their habitat. Our evaluation of potential measures included
consideration of the following factors in relation to one another:
the manner in which, and the degree to which, the
successful implementation of the measure is expected to minimize
adverse impacts to marine mammals
the proven or likely efficacy of the specific measure to
minimize adverse impacts as planned
the practicability of the measure for applicant
implementation, including consideration of personnel safety,
practicality of implementation.
Based on our evaluation of the applicant's proposed measures, as
well as other measures considered by NMFS or recommended by the public,
NMFS has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable adverse impacts on
marine mammals species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting Measures
In order to issue an ITA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth ``requirements pertaining to
the monitoring and reporting of such taking''. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for IHAs
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. The proposed monitoring and
reporting measures for the Manette Bridge replacement project are
provided below.
1. Marine Mammal Observers
WSDOT proposes that a minimum of two qualified and NMFS-approved
marine mammal observers (MMOs) would be present on site at all times
during steel pile driving. In order to be considered qualified, WSDOT
lists the following requirements for prospective MMOs:
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. MMOs shall use
binoculars to correctly identify the target.
Advanced education in biological science, wildlife
management, mammalogy or related fields (Bachelors degree or higher is
preferred).
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 (cetaceans and pinnipeds), including the identification
of behaviors.
Sufficient training, orientation or experience with the
construction operation to provide for personal safety during
observations.
[[Page 13512]]
Writing skills sufficient to prepare a report of
observations.
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. Marine Mammal Monitoring
WSDOT has developed a monitoring plan (Appendix G of the WSDOT IHA
application) in conjunction with NMFS that will collect sighting data
for each distinct marine mammal species observed during the proposed
Manette Bridge replacement construction activities that generate
intense underwater noise. These activities include, but are not limited
to, impact and vibratory pile driving, use of dynamic positioning
system by construction and supporting vessels, and sediment dredging.
Marine mammal behavior, overall numbers of individuals observed,
frequency of observation, and the time corresponding to the daily tidal
cycle will also be included. An example of a marine mammal sighting
form is included in Appendix I of the WSDOT's IHA application.
In addition, for impact pile driving, WSDOT proposes the following
Marine Mammal Monitoring Plan and shut down procedures:
At least two MMOs will be on site to monitor the safety
and influence zones by using a range finder or hand held global
positioning system (GPS) device. The zone will be monitored by driving
a boat along and within the radius while visually scanning the area,
and or monitoring from shore if there is a vantage point that will
allow full observation of the zone.
If the safety zone is obscured by fog or poor lighting
conditions, pile driving will not be initiated until the entire safety
zone is visible.
The safety zone will be monitored for the presence of
marine mammals for 30 minutes prior to impact pile driving, during pile
driving, and 20 minutes after pile driving activities.
No impact pile driving will be started if a marine mammal
is detected within the respective safety zones. Pile driving may begin
if a marine mammal is seen leaving the safety zone, or 30 minutes has
elapsed since the marine mammal is last seen inside the safety zone.
If marine mammals are observed, their location in relation
to the safety and influence zones, and their reaction (if any) to pile
driving activities will be documented.
Monitoring of the safety zone will continue for 20 minutes
following the completion of pile driving.
3. Reporting
WSDOT shall submit weekly marine mammal monitoring reports from the
time when in-water construction activities are commenced to NMFS Office
of Protected Resources (OPR). These weekly reports would include a
summary of the previous week's monitoring activities and an estimate of
the number of marine mammals that may have been disturbed as a result
of in-water construction activities.
In addition, if an IHA is issued to WSDOT for the incidental take
of marine mammals from the proposed Manette Bridge replacement project,
WSDOT shall provide NMFS OPR with a draft final report within 90 days
after the expiration of the IHA. This report should detail the
monitoring protocol, summarize the data recorded during monitoring, and
estimate the number of marine mammals that may have been harassed due
to the construction activities. If no comments are received from NMFS
OPR within 30 days, the draft final report will be considered the final
report. If comments are received, a final report must be submitted
within 30 days after receipt of comments.
Estimated Take by Incidental Harassment
As mentioned earlier in this document, the potential effects to
marine mammals from the proposed activities include disturbance from
increased human presence and marine traffic and from noises generated
from the construction work such as pile driving and dredging
activities. The proposed mitigation measures of using air bubble
curtain systems would prevent marine mammals from onset of TTS by
impact pile driving and reduce Level B behavioral harassment due to the
effective attenuation by the air bubble systems. Therefore, the
following analyses focus on potential noise impacts that could cause
Level B behavioral harassment, based on the WSDOT contracted surveys
for the entire proposed project area (WSDOT 2009).
1. Harbor Seal
There are no harbor seal haulouts within 3 miles (4.8 km) of the
project. The nearest haulout is in Dyes Inlet and animals must move
through the Port Washington Narrows to access Sinclair Inlet and the
greater Puget Sound. Individual harbor seals moving between Sinclair
and Dyes Inlets would be exposed to project activities.
A total of 34 harbor seals were detected during ten surveys
conducted during the same time of year pile driving will occur, between
July and January. The age, sex and reproductive condition of the
animals was not determined. For the proposed Manette Bridge replacement
activities, it is reasonable to assume that similar numbers of animals
would be encountered during an average 10-day period. WSDOT anticipates
that for every day of construction activities, between 3 and 4 harbor
seals may be encountered, although it is possible that some of these
animals will be the same individuals. If in-water construction
activities occur every day of the year (258 days between June 15 and
February 28), approximately 877 harbor seals (or about 6% of the
Washington inland waters stock of harbor seals) could be encountered in
the vicinity of the proposed bridge replacement work. However, it is
not likely that every harbor seal would be taken by Level B behavioral
harassment since not every animal would be exposed to received levels
above 160 dB re 1 microPa (rms) from an impulse source (such as impact
pile driving) or above 120 dB re 1 microPa (rms) from a non-impulse
source (such as vibratory pile driving or dredging). Likewise, not
every single harbor seal would respond to the sight of human or vessel
traffic in the vicinity of the project area. Therefore, the estimated
number of 877 represents the upper-limit of the number of harbor seals
that could be affected by Level B behavioral harassment as a result of
exposure to Manette Bridge replacement related construction activities.
2. California Sea Lion
There are no California sea lion haulouts within three miles of the
project. The nearest haulout is in Rich Passage, east of the Port
Washington Narrows in more open water. Individual California sea lions
moving between Sinclair and Dyes Inlets could be exposed to project
activities.
A total of one, possibly two California sea lions were detected
during ten surveys conducted during the same time of year pile driving
would occur, between July and January. The age, sex and reproductive
condition of the animals was not determined. For the proposed Manette
Bridge replacement activities, it is reasonable to assume that similar
numbers of animals would be encountered during an average 10-day
period. WSDOT anticipates that for every 10 days of construction
activities, between 1 and 2 California sea lions may be encountered,
although it is possible that some of these animals will
[[Page 13513]]
be the same individuals. If in-water construction activities occur
every day of the year (258 days between June 15 and February 28), up to
516 California sea lions (or about 0.2% of the US stock of California
sea lions) could be encountered in the vicinity of the proposed bridge
replacement work. However, it is not likely that every California sea
lion would be taken by Level B behavioral harassment since not every
animal would be exposed to received levels above 160 dB re 1 microPa
(rms) from an impulse source (such as impact pile driving) or above 120
dB re 1 microPa (rms) from a non-impulse source (such as vibratory pile
driving or dredging). Likewise, not every single California sea lion
would respond to the sight of human or vessel traffic in the vicinity
of the project area. Therefore, the estimated number of 516 represents
the upper-limit of the number of harbor seals that could be affected by
Level B behavioral harassment as a result of exposure to Manette Bridge
replacement related construction activities.
3. Steller Sea Lion
As stated earlier, the nearest Steller sea lion haulout is
approximately 12 miles (19.3 km) northeast of the proposed project area
in Shilshole Bay on the east side of the Puget Sound, adjacent to the
city of Seattle. No Steller sea lions were sighted during the ten
surveys contracted by WSDOT, and NMFS considers it is very unlikely
that a Steller sea lion would occur in the vicinity of the proposed
project area. The implementation of the aforementioned mitigation
measures, including halting all pile driving and dredging activities
and turning off construction vessels' dynamic positioning systems when
a Steller sea lion is detected about to enter the zone of influence
(received levels at or above 160 dB re 1 microPa (rms) for impulse
noise or 120 dB re 1 microPa (rms) for non-impulse noise). Therefore,
NMFS does not believe Steller sea lion would be affected.
4. Killer Whale
Killer whales (southern resident) have been documented in the
project vicinity once in the last ten years (WSDOT 2009). No killer
whales were sighted during the ten surveys contracted by WSDOT, and
NMFS considers it rare that a killer whale would occur in the vicinity
of the proposed project area. The implementation of the aforementioned
mitigation measures, including halting all pile driving and dredging
activities and turning off construction vessels' dynamic positioning
systems when a killer whale is detected about to enter the zone of
influence (received levels at or above 160 dB re 1 microPa (rms) for
impulse noise or 120 dB re 1 microPa (rms) for non-impulse noise).
Therefore, NMFS does not believe killer whale would be affected.
5. Gray Whale
Individual gray whales have been observed near the project area in
four of the last eight years (WSDOT 2009). No gray whales were sighted
during the ten surveys contracted by WSDOT, and NMFS considers it rare
that a gray whale would occur in the vicinity of the proposed project
area. Most grays whales spend winters in their breeding/calving grounds
around Baja California and summers in feeding grounds around Bering Sea
and the Arctic. The few gray whales that occur in the vicinity of the
proposed project area are likely the ones visiting the area on their
north-south migration route. Based on past occurrence of gray whales in
the area and using conservative probability estimate, NMFS considers
that no more than 2 individuals of gray whales (0.01% of the Eastern
North Pacific gray whale population) would be exposed to underwater
construction noise SPL that could cause Level B behavioral harassment
annually as a result of the proposed Manette Bridge replacement
project.
Negligible Impact and Small Numbers Analysis and Determination
Pursuant to NMFS' regulations implementing the MMPA, an applicant
is required to estimate the number of animals that will be ``taken'' by
the specified activities (i.e., takes by harassment only, or takes by
harassment, injury, and/or death). This estimate informs the analysis
that NMFS must perform to determine whether the activity will have a
``negligible impact'' on the species or stock. Level B (behavioral)
harassment occurs at the level of the individual(s) and does not assume
any resulting population-level consequences, though there are known
avenues through which behavioral disturbance of individuals can result
in population-level effects. A negligible impact finding is based on
the lack of likely adverse effects on annual rates of recruitment or
survival (i.e., population-level effects). An estimate of the number of
Level B harassment takes alone is not enough information on which to
base an impact determination.
In addition to considering estimates of the number of marine
mammals that might be ``taken'' through behavioral harassment, NMFS
considers other factors, such as the likely nature of any responses
(their intensity, duration, etc.), the context of any responses
(critical reproductive time or location, migration, etc.), as well as
the number and nature of estimated Level A takes, the number of
estimated mortalities, and effects on habitat.
The WSDOT's specified activities have been described based on best
estimates of the planned Manette Bridge replacement project within the
proposed project area. Some of the noises that would be generated as a
result of the proposed bridge replacement project, such as impact pile
driving, are high intensity. However, WSDOT plans to use vibratory pile
driving and to avoid using impact pile driving as much as possible,
therefore eliminating the intense impulses that could cause TTS to
marine mammals when repeatedly exposed in close proximity. In addition,
WSDOT indicates that if impact pile driving is to be conducted, an air
bubble curtain system would be used to attenuate the noise level.
Furthermore, shutdown of pile driving would be implemented when a
marine mammal is spotted within the 180 dB and 190 dB re 1 microPa
(rms) safety zones for cetaceans and pinnipeds, respectively.
Therefore, NMFS does not expect that any animals would receive Level A
(including injury) harassment or Level B TTS from being exposed to
intense construction noise.
Animals exposed to construction noise associated with the proposed
bridge replacement work would be limited to Level B behavioral
harassment only, i.e., the exposure of received levels for impulse
noise between 160 and 180 dB re 1 microPa (rms) (from impact pile
driving) and for non-impulse noise between 120 and 180 dB re 1 microPa
(rms) (from vibratory pile driving, dredging, and dynamic positioning
of construction vessels). In addition, the potential behavioral
responses from exposed animals are expected to be localized and short
in duration. The modeled 160 dB isopleths from impact pile driving is
5,412 m from the pile, and the estimated 120 dB isopleths from
vibratory pile driving is approximately 1,900 m from the pile. However,
the actual zone of influence from impact pile driving is expected to be
much smaller due to other sound attenuation factors not considered in
the spreading model. Furthermore, although in-water construction
activities are expected to be conducted everyday during daylight hours
between June 15 and February 28, the total duration for pile driving is
expected to be approximately 410 hours, or 41 working days based on 10
hours of daylight for
[[Page 13514]]
each working day. WSDOT also plans to use barge anchoring instead of
dynamic positioning systems for construction vessels, thus further
reducing noise input into the water column. Therefore, the underwater
noise impacts from the proposed Manette Bridge replacement construction
is expected to have a low level of noise intensity, and be of short
duration and localized. These low intensity, localized, and short-term
noise exposures, when received at distances of Level B behavioral
harassment (i.e., 160 dB re 1 microPa (rms) from impulse sources and
120 dB re 1 microPa (rms) from non-impulse sources), are expected to
cause brief startle reactions or short-term behavioral modification by
the animals. These brief reactions and behavioral changes are expected
to disappear when the exposures cease. Therefore, these levels of
received underwater construction noise from the proposed Manette Bridge
replacement project are not expected to affect marine mammal annual
rates of recruitment or survival.
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 mitigation and
monitoring measures, NMFS preliminarily finds that the Manette Bridge
replacement project will result in the incidental take of small numbers
of Pacific harbor seals, California sea lions, and gray whales by Level
B harassment only, and that the total taking from harassment will have
a negligible impact on 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.
Endangered Species Act (ESA)
There are two marine mammal species and two fish species that are
listed as endangered or threatened under the ESA with confirmed or
possible occurrence in the study area: Eastern North Pacific Southern
Resident killer whale, Eastern U.S. Steller sea lion, Chinook salmon,
and steelhead trout. Under section 7 of the ESA, the Federal Highway
Administration (FHWA) and WSDOT have consulted with NMFS Northwest
Regional Office (NWRO) on the proposed Manette Bridge replacement
project. In a memo issued with its August 3, 2009, Biological Opinions,
NMFS NWRO stated that the proposed bridge replacement may effect, but
is not likely to adversely affect the listed marine mammal species and
stocks.
The proposed issuance of an IHA to WSDOT constitutes an agency
action that authorizes an activity that may affect ESA-listed species
and, therefore, is subject to section 7 of the ESA. Moreover, as the
effects of the activities on listed marine mammals and salmonids were
analyzed during a formal consultation between the FHWA and NMFS, and as
the underlying action has not changed from that considered in the
consultation, the discussion of effects that are contained in the
Biological Opinion and accompanying memo issued to the FHWA on August
3, 2009, pertains also to this action. In conclusion, NMFS has
determined that issuance of an IHA for this activity would not lead to
any effects to listed species apart from those that were considered in
the consultation on FHWA's action.
National Environmental Policy Act (NEPA)
NMFS is in the process of preparing an Environmental Assessment
(EA) for the take of marine mammals incidental to the Manette Bridge
replacement construction activities, and will make a final NEPA
determination before issuing a final IHA.
Dated: March 16, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2010-6248 Filed 3-19-10; 8:45 am]
BILLING CODE 3510-22-S